ISSN 00450421

Volume 62 Number 4 December 2017

SPECIALRESEARCH

SUPPLEMENTAustralian Dental Research Foundation

Australian Dental

JournalThe offi cial journal of the

Australian Dental Association

IntroductionAs Chair of the Australian Dental Research Foundation (ADRF), I am excited about the publication of theresearch work presented in this Special Research Supplement of the Australian Dental Journal for 2017. Theseabstracts come from a range of senior, early career and postgraduate researchers. For many undergraduates, it willbe their first published paper, the first step on the pathway to becoming a dental and oral health researcher and toensure the continuation of research.The core function of ADRF is to support research and in reading the articles you may recall your own student

days. Reflecting where you were then and where you are now. Think about the advances in the way you practicedentistry in 2017. All the improvements are down to researchers, whether they be in universities or industry.ADRF grants are assisting to build the knowledge base and striving to improve better outcomes for patients – winsfor the profession and the community. I hope you benefit from reading this year’s abstracts.From my personal involvement with ADRF and understanding the transparency and rigor applied to selecting

the successful grant applicants we have established a ‘Friends of the ADRF Bequest Club’.There are three levels of membership:

• Gold $100,000 plus

• Silver $50,000 plus

• Bronze $25,000 plus

I’m hoping that some of you will join me in leaving a bequest in your will for the ADRF – I am proud to be aGold Member. Details of how you can become a ‘Friend’ can be obtained by email: adrf@dentalresearch.org.auor look on our webpage www.ada.org.au/ADRFThis should help secure the future of ADRF and of course we need funding now to continue the work of ADRF.

We also accept donations or supporter contributions and $2 or more are tax deductible.I would like to thank our regular donors and supporters, the Australian Dental Association (ADA) and the Aus-

tralian Dental Industry Association (ADIA) and the volunteer Board of Directors and Committee members whosupport the ADRF with time and money. A special thanks to Jane Levey, ADRF Services Officer, who handles theadministration tasks so smoothly.ADRF really appreciates the opportunity to present these abstracts to you and are indebted to the Australian

Dental Journal Editor and Editorial Advisory Board for their continuing support in publishing this special annualsupplement.

Pam Clark AO

ChairAustralian Dental Research Foundation

Australian Dental JournalThe official journal of the Australian Dental Association

CONTENTS

ADRF Special Research SupplementVolume 62 No 4 December 2017

ADRF Research Grant Abstracts S5 Development of a modular index of children’s dental anxiety and fear

JM Armfi eld, S Chrisopoulos, DL Chi

S5 The role of carbamylated proteins in the pathology of periodontal diseaseR Bright, PM Bartold

S6 The effect of two sodium hypochlorite gels on the structural and chemical properties of dentine, tissue dissolution, and their antimicrobial effi cacy in vitroS Cochrane, M Burrow, P Parashos

S7 Role of autophagy and apoptosis in the pathogenesis of bone erosion in chronic periodontitisAASSK Dharmapatni, PM Bartold, TN Crotti, DR Haynes

S7 Infl uence of access cavity designs, root canal enlargement and short-term calcium hydroxide intracanal medicament on fracture susceptibility of root-fi lled teethR Haddadin, PV Abbott, T Sercombe, N Boyd

S8 Effect of probiotics treatment in an experimental model of periodontitisSM Gatej, PM Bartold, N Gully

S9 The role of foetal hyperglycaemia in the formation of cleft lip and maxillary hypoplasia A Howe, HE Ritchie, DJ Oakes

S9 Change in oral health status as a predictor of change in general health and food consumption in community-dwelling adults aged 75 years or olderS Islam, D Brennan, K Roberts-Thomson

S10 Genomic alterations of young patients with oral cancer M Jessri, A Dalley, CS Farah

S11 Progression from dysplasia to cancer M Jessri, A Dalley, CS Farah

S11 Detection of tooth-coloured restorative materials based on their optical propertiesR Kiran, J Chapman, M Tennant, A Forrest, LJ Walsh

S12 Fluorescence properties of tooth-coloured restorative materials assessed using a fl uorescence DSLR cameraR Kiran, J Chapman, M Tennant, A Forrest, LJ Walsh

S13 The effect of immune genetic variants on chemotherapy-induced gastrointestinal toxicity (CIGT) risk in patients receiving 5-fl uorouracilSK Korver, IA Ball, RJ Gibson, RM Logan, CS Karapetis, DM Keefe, JM Bowen, JK Coller

S14 Maternal and perinatal factors associated with early childhood cariesKG Peres

S14 Assessment of mandibular canal clarity using two-dimensional (2D) and three-dimensional (3D) radiographic imagesK Shah, E Ports, R Yong, S Mihailidis, A Brook, P Anderson, G Townsend, S Ranjitkar

S15 Effect of local delivery of VEGF-Hydrogel on BRONJ lesion and local gene expression in rat model – an in vivo and in vitro studyD Sharma, S Hamlet, EB Petcu, S Ivanovski

S16 Cytokine profi les in serum and placenta of pregnant mice following experimentally induced periodontitisK Tian, M Macowan, TR Fitzsimmons, CT Roberts, PS Zilm

S17 How do Australian community pharmacists and pharmacy assistants manage non-healing mouth ulcer presentations and do they refer?BJ van Rensburg, CR Freeman, PJ Ford, MW Taing

S17 Comparison of different guided bone regeneration membranes in healthy and osteoporotic sheepC Vaquette, M Tavazoei, DW Hutmacher, S Ivanovski

Contents continued

S18 The infl uence of slime/capsule on biofi lm formation in response to tetracycline and sodium hypochlorite by clinical isolates of Enterococcus faecalisA Yoo, G Rossi-Fedele, SP Kidd, AH Rogers, PS Zilm

ADRF Dental Student Research Grant Abstracts S19 Effect of matriptase on lymph node mast cell accumulation after UV exposure

S Basha, NMM Hassan (Supervisor)

S20 Extensive phenotyping of the orofacial and dental complex in Crouzon syndromeA Khominsky, R Yong, S Ranjitkar, GC Townsend, PJ Anderson (Supervisors)

S20 Investigation of the extra-oral migration of Fusobacterium nucleatum subspnucleatum and its role in adverse pregnancy outcomesK Tian, R Wilson, C Roberts, S Kidd, P Zilm (Supervisor)

Colin Cormie Grant S21 The effect of incident beam angle and horizontal distance of the light-curing unit on the degree of polymerisation

in photo-initiated composite resin dental restorative materialsCY Yang, MJ Liddell, EA Jennings, P Buttner, N Meredith

ADRF Research Grant Abstracts

Development of a modular index of children’s dental anxiety and fearJM Armfield,* S Chrisopoulos,* DL Chi†

Measures of dental anxiety are central to studies ofchild dental fear in that they necessarily define theconcept being explored. Therefore, it is crucial thatthey are valid, reliable and are based on explicit theo-retical foundations. The Children’s Index of DentalAnxiety and Fear (CIDAF-4C+) was designed toaddress the theoretical shortcomings of existing chil-dren’s dental fear scales by measuring the emotional,behavioural, physiological, and cognitive componentsof dental anxiety. The CIDAF-4C+ comprises a modu-lar design with three sections assessing the four com-ponents of dental anxiety and fear (CIDAF-4C),dental phobia (CIDAF-P) and anxiety-invoking stimuli(CIDAF-S). The aim of the study was to assess relia-bility and validity information on the CIDAF-4C+ in asample of Australian children.Eighty-three parents and children from Western

Australia completed a questionnaire distributedthrough public school dental service clinics. Itemselection for the final scale was determined by exami-nation of item response distributions, intercorrela-tions, and test-retest correlations, as well asexploratory factor analysis (EFA). Validation of theCIDAF-4C was undertaken by testing correlations

with the Smiley Faces Paper Scale (SFPS), cognitivevulnerability-related perceptions and dental visitinghistory.An eight-item scale was created from a pool of 16

positively and negatively worded items. The scaleassesses positive and negative valence (four itemseach) related to dental visiting. The CIDAF-4Cshowed good internal consistency (a = 0.90; singlemeasures intraclass correlation = 0.52) and acceptabletest-retest reliability at two weeks (r = 0.72). TheIDAF-4C was significantly correlated with the SFPS(r = 0.73). In comparison to the SFPS, the CIDAF-4Cbetter predicted the child having had a previousunpleasant experience at the dentist and the parent’sbelief that their child actively avoids going to the den-tist or else endures with intense fear and anxiety.The CIDAF-4C+ is a theoretically derived and use-

ful measure of dental anxiety and fear, but requiresfurther validity and reliability evidence.This abstract is based on research that was funded

entirely by the Australian Dental Research Founda-tion. The authors wish to thank the management andstaff of Dental Health Services Western Australia forsupporting the study and organising distribution ofquestionnaires.

The findings of this research were presented as a Pos-ter at the 95th General Session and Exhibition of theInternational Association for Dental Research (IADR)held in San Francisco, California, USA, March 2017.

The role of carbamylated proteins in the pathology of periodontal diseaseR Bright, PM Bartold

Extra-articular citrullination and production of anti-citrullinated protein antibodies (ACPA), as a primingimmunological experience, is well documented inmany tissues including the inflamed gingival tissuesassociated with periodontal disease. More recently,carbamylation of proteins has also been implicated inthe pathogenesis of rheumatoid arthritis in a mannersimilar to citrullination. Carbamylation is a posttranslational modification of proteins by an enzyme-independent reaction of lysine residues against whichautoantibodies are subsequently induced. We hypothe-sized that inflammation caused by bacteria associatedperiodontal disease is an extra-synovial source of car-bamylation and the formation of autoantibodies seen

in rheumatoid arthritis. Initially, we want to identifycarbamylated proteins in gingival tissue and gingivalcrevicular fluid from health and periodontal disease(PD) subjects.Samples selected for immunohistochemistry (in situ

detection of carbamylated proteins in formalin fixedparaffin embedded gingival tissue) represented a rangeof PD severity. To identify carbamylated proteins inthe gingival cervical fluid a proteomic approach wasundertaken. Proteins from gingival crevicular fluidwere eluted from filter strips using 100 mM ammo-nium bicarbonate buffer and dehydrated in 100% ace-tonitrile. Samples were transported to the AdelaideProteomic Centre, digested by trypsinisation then run

*Australian Research Centre for Population Oral Health, AdelaideDental School, University of Adelaide, Adelaide, South Australia,Australia.†Department of Oral Health Sciences, University of Washington,Seattle, Washington, USA.Email: jason.armfield@adelaide.edu.au

© 2017 Australian Dental Association S5

on the Nano LC-ESI-MS/MS Orbitrap. The MS spec-tra obtained were analyzed using flexAnalysis soft-ware (version 3.3, Bruker Daltonics) employingsmoothing, background subtraction and peak detec-tion algorithms.Gingival tissue from patients with PD were positive

for carbamylated proteins when compared to healthysubjects. Increased positive staining for carbamylatedproteins was observed with increasing severity of dis-ease. Six samples were analyzed by mass spectrometrycorresponding to the samples used in the immunohis-tochemical study. Spectral analysis identified numer-ous carbamylated proteins.

We have confirmed the presence of carbamylatedproteins in gingival tissue and gingival crevicular fluid.It was also evident that increasing amounts of proteincarbamylation were associated with increasing severityof disease. These results may lead to new biomarkersof periodontal disease and rheumatoid arthritis. Asimple non-invasive test using gingival crevicular fluidcould be used to detect early disease allowing inter-vention prior to disease onset.However, the methodology from collection of gingi-

val crevicular fluid to the spectral analysis will needto be optimised and a larger cohort studied. Further-more, it would also be of interest to analyze salivasamples for the presence of carbamylated proteins.

The support of the Australian Dental Research Foun-dation is gratefully acknowledged.

The effect of two sodium hypochlorite gels on the structural and chemicalproperties of dentine, tissue dissolution, and their antimicrobial efficacyin vitroS Cochrane,* M Burrow,* P Parashos*

To evaluate the effect of 0.5% and 1% NaOCl gels,calcium hydroxide, Odontopaste�, and 1% and 4%NaOCl solutions on the mechanical properties ofhuman and bovine root dentine.This laboratory-based study used standardized

human and bovine dentine bars allocated to one salinecontrol group (n = 15) and six experimental groups(n = 15): calcium hydroxide; Odontopaste�; 0.5%NaOCl gel; 1% NaOCl gel; 1% NaOCl solution; and4% NaOCl solution. The bars were exposed to themedicaments for seven days and then immediatelysubjected to a three-point bend test followed by Vick-ers microhardness test. Data were analyzed usinganalysis of variance with Fisher’s pairwise comparisonto compare the medicaments and substrates.When the control and experimental groups were com-

bined, human dentine displayed a significantly highermodulus of elasticity and microhardness and lower flex-ural strength compared with bovine dentine. Exposureto calcium hydroxide and Odontopaste� did not resultin a significant change in the mechanical properties ofhuman dentine. However, calcium hydroxide did resultin a significantly lower flexural strength of bovine den-tine (P < 0.05). Exposure to the 0.5% NaOCl gel didnot result in a significant reduction in the elastic modu-lus of human dentine, but there was a significant

decrease in flexural strength and microhardness. The0.5% NaOCl gel resulted in a significant reduction inthe elastic modulus, flexural strength and microhard-ness of bovine dentine compared with the control. Indecreasing order of the modulus of elasticity, flexuralstrength and microhardness values, exposure to the 1%NaOCl gel, 1% NaOCl solution and 4% NaOCl solu-tion resulted in significant reductions in both humanand bovine dentine compared with the control (saline).Whilst there were significant differences in the

mechanical properties of human and bovine dentine,similar trends were seen in the experimental groups.Therefore, bovine dentine appears to be a suitablesubstrate in laboratory-based studies assessing theeffect of medicaments on the mechanical properties ofdentine. However, the actual values will be different.Therefore, the results from bovine dentine cannot bedirectly extrapolated to human dentine. The 0.5%and 1% NaOCl gels resulted in a significant detrimen-tal effect on the mechanical properties of human andbovine dentine when compared with the control,calcium hydroxide and Odontopaste�. Therefore,within the limitations of this study, the use of a 0.5%or 1% NaOCl gel as an intracanal medicament shouldbe used with caution until further laboratory-basedstudies are undertaken.

This abstract is based on research that was funded bythe Australian Dental Research Foundation, Mel-bourne Dental School, and the Australian Society ofEndodontology.

University of Adelaide, Adelaide, South Australia, Australia.Email: richard.bright@adelaide.edu.au

*The Melbourne Dental School, Faculty of Medicine, Dentistry andHealth Sciences, The University of Melbourne, Melbourne, Victoria,Australia.Email: parashos@unimelb.edu.au

S6 © 2017 Australian Dental Association

Abstracts

Role of autophagy and apoptosis in the pathogenesis of bone erosion inchronic periodontitisAASSK Dharmapatni,* PM Bartold,† TN Crotti,* DR Haynes*

Chronic periodontitis (CP), is a destructive inflamma-tory disease of periodontium, which leads to alveolarbone loss. Bone loss is associated with an increase information and activity of osteoclasts. Interplaybetween autophagy (a cell survival mechanism) andapoptosis (a cell death mechanism) may be involvedin the pathogenesis of inflammation and bone loss inCP. Anti-inflammatory effects of Azithromycin havebeen associated with autophagy and apoptosis in vari-ous cell types. However, its effects on human osteo-clasts remains elusive. Therefore, the aim of this studywas to identify the effect of autophagy modulators(Hydroxychloroquine/HCQ and Rapamycin) andapoptosis modulator (Embelin) compared to Azithro-mycin on human peripheral blood monocytes(PBMC)-derived osteoclasts in vitro. We hypothesizethat autophagy and apoptosis modulators affect osteo-clast formation and activity.PBMCs from four healthy donors were cultured

over 17 days and stimulated with RANKL andM-CSF to generate osteoclasts. Cells were pretreatedwith TNF-a (5 ng/mL) for 24 h, followed by eitherAzithromycin (20 lg/mL), autophagy inhibitor HCQ(50 lg/mL), autophagy inducer Rapamycin (100 lM)or Embelin (15 lmol/L) for 6 h and 24 h. Sampleswere collected to identify osteoclast formation usingTRAP staining, as well as osteoclast activity using adentine resorption assay. Live cell imaging was used

to investigate real time changes in cellular morphol-ogy. Real time PCR was used to investigate geneexpression for osteoclasts (CTR, NFATc1, OSCAR),autophagy (LC3, p62, beclin-1) and apoptosis(caspase-3, caspase-9). Immunofluorescent stainingand TUNEL were used to detect the expression ofautophagy proteins and apoptosis respectively.There was a significant decrease in TRAP-positive

cells between 6 h and 24 h of Azithromycin andHCQ-treated cells over time (P < 0.05). Over time,HCQ and Embelin, but not Azithromycin, signifi-cantly reduced cell size. HCQ and Embelin, but notAzithromycin, significantly reduced osteoclast dentineresorption (P < 0.05). There was no change in geneexpression for osteoclasts, autophagy or apoptosis inany of the treatments, but protein expression andTUNEL positive cells were detectable.The results suggest that Azithromycin reduces

osteoclast formation, but not resorption activity orgene expression levels. However, autophagy proteinsand apoptosis were observed, which suggests possibleinvolvement of protein translational modificationswith Azithromycin treatment. Autophagy or apoptosismodulators reduced osteoclast formation and activity,hence supporting our initial hypothesis.The researchers thank the Australian Dental

Research Foundation (Grant Number:49-2015) andvisitors involved in the EU “Refined Step Project”:Benedikt Regner, James Pegg and Sidrah Chaudaryfor their involvement in this work.

The results of this research were presented at theAdelaide Dental School Research Day, University ofAdelaide, South Australia, Australia, July 2017.

Influence of access cavity designs, root canal enlargement and short-termcalcium hydroxide intracanal medicament on fracture susceptibility ofroot-filled teethR Haddadin,* PV Abbott,* T Sercombe,*† N Boyd*

Fracture of root-filled teeth is a common problem thatleads to extraction. Parameters that increase the sus-ceptibility of these teeth to fracture are of interest.The aim was to study the effect of simulated chewing,access cavity design/size, canal preparation size and

calcium hydroxide on the susceptibility of root-filledand restored teeth to fracture.An in vitro controlled trial was conducted using

human mandibular molars without previous restora-tion. All samples had standardized endodontic

*Discipline of Anatomy and Pathology, School of Medicine, TheUniversity of Adelaide, Adelaide, South Australia, Australia.†Colgate Australian Clinical Dental Research Centre, School ofDentistry, The University of Adelaide, Adelaide, South Australia,Australia.Email: a.dharmapatni@adelaide.edu.au

© 2017 Australian Dental Association S7

Abstracts

treatment (except the variable being tested) and anamalgam restoration. Two access cavity designs: con-servative (CONS) and straight-line (SLA) were tested.Root canal preparations using Hedstr€om files (HF),ProTaper Ni-Ti rotary files (PT), or ProTaper plusSystemGT Ni-Ti rotary files (GT) were compared. Inone group, intra-canal Ca(OH)2 paste was placed forfour weeks prior to root canal filling and restoration.Teeth were mounted in acrylic with a simulated peri-odontal ligament. The forces required to fracture theteeth were determined with an Instron Universal TestMachine.The effect of simulated chewing was insignificant in

the experimental model. Differences were insignificantbetween the mean forces required to fracture teeththat had conservative, straight-line access cavity orremained intact; with or without simulated chewing,and those that had various root canal preparations.

The mean force for fracture teeth with short-term cal-cium hydroxide treatment was not significantly differ-ent from controls.Simulated chewing, extent of access cavity prepara-

tions, the degree of root canal enlargement and short-term use of calcium hydroxide medicament had noeffect on the force required to fracture mandibularmolars with intact marginal ridges and amalgamrestorations in the access cavity. Overall, root canaltreatment per se did not affect fracture susceptibilityof teeth with intact marginal ridges.This research was funded by an Australian Dental

Research FoundationResearch Grant, an InternationalFederation of Endodontic Associations ResearchAward, and an Australian Society of EndodontologyInc. Postgraduate Endodontic Research Grant.

The findings of this research were presented at the 9thWorld Endodontic Congress (30th IFEA meeting andthe 34th IKAE) in Tokyo, Japan, May 2013 as OralResearch Presentation OP.25 Titled – Effects of Simu-lated Chewing and Access Cavity Design on Strengthof Teeth.

Effect of probiotics treatment in an experimental model of periodontitisSM Gatej, PM Bartold, N Gully

Previous studies have shown that probiotics may playa role in the management of periodontitis. The aim ofthis study was to investigate the role of probioticswith anti-microbial and anti-inflammatory propertiesin the prevention of bone loss in an established mousemodel of experimentally induced periodontitis.Periodontitis was induced by gavage with Porphy-

romonas gingivalis (P. gingivalis) and Fusobacteriumnucleatum (F. nucleatum). One of the most studiedprobiotics with over 800 published papers, Lacto-bacillus rhamnosus GG (LGG) was chosen for thisexperiment as it has been shown to exhibit anti-inflammatory properties in vivo and it does not fer-ment sucrose. It was administered via two differentmethods - oral inoculation and oral gavage in miceprior and during the induction of periodontitis. Thetreated groups were compared with animals with peri-odontitis alone and with controls. Alveolar bone andgingival tissue changes were assessed using live animalmicro-computed tomography scans and histologicalanalysis. Weights of the animals were recorded weeklyfor the duration of the study. Serum levels of C-reactiveprotein were used to monitor inflammation.

The results showed a statistically significantincrease in the cemento-enamel junction to the alve-olar bone crest (CEJ-ABC) length for the periodonti-tis group reflective of increased bone loss. However,control mice or mice with experimental periodontitispreviously treated with probiotics (either via oralinoculation or oral gavage) showed no statisticallysignificant bone loss. Serum levels of mouse CRPwere not statistically significantly different betweengroups. By the end of the experiment all animalsput on weight except the groups administered probi-otic orally.The results of this study indicate that the use of

LGG prior to inducing experimental periodontitis leadto insignificant bone loss for all probiotic treatedgroups when compared with controls. Statisticallythere was no difference between the two deliverymethods used (oral gavage or oral inoculation). In thefuture, LGG may offer a low-risk, easy to use adjunctoption for the management of periodontitis.The support of the Australian Dental Research

Foundation is gratefully acknowledged.

The findings from this research were presented at theUniversity of Adelaide School of Dentistry ResearchDay 2017.

The University of Adelaide, Adelaide, South Australia, Australia.Email: mark.bartold@adelaide.edu.au

*School of Dentistry, University of Western Australia, Perth,Western Australia, Australia.†School of Mechanical and Chemical Engineering, University ofWestern Australia, Perth, Western Australia, Australia.Email: paul.v.abbott@uwa.edu.au

S8 © 2017 Australian Dental Association

Abstracts

The role of foetal hyperglycaemia in the formation of cleft lip and maxillaryhypoplasiaA Howe,* HE Ritchie,† DJ Oakes†

Many women need to take phenytoin to control epi-lepsy and must remain on the drug during pregnancy.Yet it is the most common drug-induced cause of cleftlip and maxillary hypoplasia. The cause of the malfor-mations is unknown but both hypoxia and hypergly-caemia are possible candidates. Using an animal modeldeveloped by the authors, we explored the effect ofphenytoin on the expression of embryonic genes likelyto be involved in responses to these interlinked stresses.Pregnant rats were given a teratogenic dose of

phenytoin during the critical period of craniofacialdevelopment (GD11) and embryos collected 2, 8 or24 h later. Embryos were collected from four animalsat each time point. Embryos from each litter were dis-sected free of surrounding tissues, pooled, placed in‘RNAlater’ solution and stored at �20°C prior toribonucleic acid (RNA) extraction. Real time quanti-tative polymerase chain reaction (PCR) was per-formed using RNA extracts to determine expressionof the following genes of: hypoxia pathway (HIF1a,VEGF), antioxidant pathways (SOD1), glucose trans-porter (GLUT1) and cell death (Tnfa1).Phenytoin-treated rats showed a spike in blood glu-

cose 2–8 h after dosing. This coincided with an

increased expression of the glucose transporter geneand VEGF (1.4 and 1.4 fold increase respectively) inphenytoin-exposed embryos compared to controls. Ateight hours, HIF1a and SOD1 transiently decreased inthe treated embryos. Surprisingly, there was no signifi-cant difference in expression patterns of Tnfa1 thatmight have been anticipated.Phenytoin is associated with increased maternal

blood glucose for a prolonged period of time. In thegenes selected for assessment, small increases inexpression of the glucose transport gene as well asVEGF were observed. Surprisingly, genes associatedwith hypoxia and antioxidant pathways (HIF1 andSOD1) were downregulated compared to controlembryos. It has been suggested that sustained hyper-glycaemia leads to localised increased oxygen con-sumption and resultant tissue hypoxia. Under normalcircumstances, hypoxia promotes cell survival strate-gies that are initiated by increased expression ofHIF1a but this system is not adequately activated indiabetic models. Our results support the hypothesisthat hyperglycaemia is associated with a downregula-tion of HIF1a. Thus, the mechanism of action ofphenytoin in causing malformations may be a resultof localised tissue hypoxia explaining the ameliorativeeffect of concomitant hyperoxia and/or insulintreatment.

The authors are grateful to the Australian DentalResearch Foundation for their support.

Change in oral health status as a predictor of change in general health andfood consumption in community-dwelling adults aged 75 years or olderS Islam, D Brennan, K Roberts-Thomson

To investigate change in general health and food intakein relation to oral health transitions in older age.This study involved a community-based sample of

older people attending their general medical practicein three Medicare Local (now Primary Health Net-works) areas in South Australia. All people aged 75years or older were invited for a health assessment,followed by a mailed questionnaire, and a food fre-quency questionnaire. After one year, a mailed ques-tionnaire and a food frequency questionnaire weresent again for follow-up.Baseline data were collected in 2014–2015 and

follow-up data in 2015–2016. Descriptive statistics

were followed by multivariate regression to assessrelations between variables. Self-reported global den-tal health transition was the explanatory variable andself-reported global general health and change in foodintake (sweet-snacks, fruits, vegetables, dairy andmeat-fish-eggs) were the outcome variables. Sex, edu-cation, diabetes, brushing habits, living status, socialsupport, satisfaction with financial situation, numberof dental visits and bleeding gums were the controlvariables. Data analysis was performed using SPSSstatistical software.At baseline, the response rate was 89.7% (n = 164),

with 58% for the food frequency questionnaire for

*Discipline of Anatomy and Histology, University of Sydney,Sydney, New South Wales, Australia.†Discipline of Biomedical Science, School of Medical Science,Faculty of Medicine, University of Sydney, Sydney, New SouthWales, Australia.Email: andrew@anatomy.usyd.edu.au

© 2017 Australian Dental Association S9

Abstracts

the first-year follow-up (n = 95). From descriptivestatistics, we found that 75% of participants reportedthat oral health stayed the same or improved and35.9% of participants reported worsened generalhealth. All the participants with worsened oral healthreported no improvement in general health. Also83.3% of participants with improved or the samedental health reported no improvement for generalhealth. Over one year, participants decreased theirconsumption of sweet-snacks, vegetables and meat-fish-eggs but increased consumption of fruits anddairy (mean (SE) change in consumption for sweet-snacks = �5.45 g (5.84); fruits = 103.44 g (18.97);vegetables = �14.98 g (6.66); dairy = 20.51 g (17.83);and meat-fish-eggs = �4.60 g (12.45).Multivariate linear regression showed that those

whose oral health stayed the same or improved com-pared to worsened reported that their general health

deteriorated (b = �0.597; P = 0.046).Worsened oralhealth had a significant association with consumption ofsweet-snacks (b = 47.17; P < 0.001) and borderline sig-nificance with vegetables (b = 31.76; P = 0.05) but noeffect on fruits (b = 38.53; P = 0.43), dairy (b = 5.36;P = 0.91) and meat-fish-eggs (b = 18.68; P = 0.49).In this group of older adults, while their oral health

improved or stayed the same, their general health dete-riorated. People who reported a worsening in their oralhealth had increased consumption of sweet-snacks.

The research reported in this paper was a study of theAustralian Primary Health Care Research Institute(APHCRI), which was supported under the AustralianGovernment’s Primary Health Care Research, Evalua-tion and Development Strategy. The information andopinions contained in it do not necessarily reflect theviews or policy of the Australian Primary Health CareResearch Institute or the Department of Health. Theauthors also gratefully acknowledge support from theInternational College of Dentists, Australasian Sec-tion, Community Oral Health Award and the Aus-tralian Dental Research Foundation (6-2015).

Genomic alterations of young patients with oral cancerM Jessri,*†‡ A Dalley,‡ CS Farah*‡

To compare the number and biological nature ofmutations in early-onset oral squamous cell cancer(OSCC) patients with those in older patients with sim-ilarly graded tumours via exome sequencing.Genomic DNA was extracted from formalin-fixed,

paraffin-embedded (FFPE) tissue from 11 early-onsetpatients (<40 years of age) with OSCC and 12matched older patients (≥60 years of age) using Geno-mic DNA Isolation Kit (Agencourt� DNAdvanceTM,Beckman Coulter, Inc., CA, USA). Barcoded sequenc-ing libraries were prepared using the Ion AmpliSeqExome Library Preparation Kit (Life Technologies)and enriched then sequenced using Ion PI Sequencing200 Kit v3 on an Ion Proton System (Life Technolo-gies). Barcoded reads corresponding to each of thelibraries were extracted from the sequencing files andthe paired-end sequence reads mapped to the referencehg19 human genome reference using the Shrimp2mapping software. The resulting SAM _le were con-verted into a coherent BAM _le using the PICARD

toolbox and SNPs and INDELs corrected using toolsfrom the GATK software to ensure that the SNPsmapped to the genome were coherent and optimal.OSCC samples from younger patients showed a

higher number of variants in DNA damage repairgenes. The main difference between the two age groupswas in the number of non-synonymous and nonsensevariants. In early onset patients, the BRCA1 gene, partof the DNA damage repair system, was the most fre-quently mutated, with a total of 57 variants. In olderpatients, the most frequently mutated gene was thetumour suppressor TP53, with a total of 28 variants.Early-onset OSCC patients are more likely to exhi-

bit mutations of genes in the DNA damage repairpathway in comparison to late-onset patients.This work was supported by the Australian Dental

Research Foundation, The Queensland GovernmentSmart Futures Investment Fund, Life Technologiesand Agilent Technologies.

The findings of this research were presented at theAustralasian Division of the International Academy ofPathology (APIAP) held in Brisbane, Qld, Australiain June 2015; the 5th World Congress of the Interna-tional Academy of Oral Oncology (IAOO) held inSao Paulo, Brazil in July 2015; and the IADR ANZDivision 55th Annual Scientific Meeting held in Dune-din, New Zealand in August 2015.

Australian Research Centre for Population Oral Health (ARCPOH),School of Dentistry, University of Adelaide, Adelaide, SouthAustralia, Australia.Email: saima.islam@adelaide.edu.au

*Australian Centre for Oral Oncology Research and Education,School of Dentistry, University of Western Australia, Nedlands,Western Australia, Australia.†Harvard School of Dental Medicine, Brigham and Women’sHospital, Boston, Massachusetts, USA.‡ UQ Centre for Clinical Research, The University of Queensland,Brisbane, Queensland, Australia.Email: camile.farah@uwa.edu.au

S10 © 2017 Australian Dental Association

Abstracts

Progression from dysplasia to cancerM Jessri,*†‡ A Dalley,‡ CS Farah*‡

To compare exomic variants in progressive and non-progressive oral potentially malignant lesions(OPMLs) and identify a molecular signature for pro-gressive lesions.Genomic DNA was isolated from 42 formalin fixed

paraffin embedded (FFPE) samples from 13 patients,five of which had progressed to oral squamous cell car-cinoma (OSCC; P1-P5) and the remaining eight non-progressive (NP1-8, followed at least seven years).Exome libraries were prepared using Ion AmpliSeqExome Library Preparation Kit and sequencing per-formed using Ion PI Sequencing 200 Kit v3 on an IonProton System (Life Technologies). The barcodedreads were extracted, the paired-end sequence readsmapped to the reference hg19 human genome usingShrimp2 mapping software. The PICARD toolbox andGATK software were used to convert the mapped datato BAM files and correct SNPs and INDELs to gener-ate coherent SNPs.Dysplastic lesions from progressive and non-

progressive patients separated using sPLS-DA (sparsePartial Least Squares Discriminant Analysis). Dysplas-tic lesions were also separated using sPLS-DA basedon lesion severity. Progressive oral epithelial dysplasia(OED) samples separated from OSCC on the first

component compared to normal oral mucosa, whilenon-progressive OED samples separated from normaltissues. DNA damage repair pathways were reportedamongst the top 10 most significantly enriched path-ways in all progressive, but not non-progressivepatients. The number of non-synonymous, nonsenseand frameshift variants in the key components of thedouble strand break (DSB) pathway and mismatchrepair (MMR) pathways were compared and progres-sive patients displayed a greater number of variantsper gene than non-progressive patients and were morelikely to display variants in these pathways.Exomic variants can be used to separate progressive

and non-progressive dysplastic lesions and to segre-gate lesions based on disease severity. Dysplasticlesions that progress to OSCC are enriched in DNAdamage repair pathways in comparison to non-progressive lesions. Mutations in the DNA damagerepair pathway have the potential to be used as amolecular signature for progressive lesions.This work was supported by the Australian Dental

Research Foundation, The Queensland GovernmentSmart Futures Investment Fund, Life Technologiesand Agilent Technologies.

The findings of this research were presented at theAustralasian Division of the International Academy ofPathology (APIAP) held in Brisbane, Qld, Australiain June 2015; the 5th World Congress of the Interna-tional Academy of Oral Oncology (IAOO) held inSao Paulo, Brazil in July 2015; and the IADR ANZDivision 55th Annual Scientific Meeting held in Dune-din, New Zealand in August 2015.

Detection of tooth-coloured restorative materials based on their opticalpropertiesR Kiran,* J Chapman,* M Tennant,† A Forrest,‡ LJ Walsh§

The availability of aesthetic restorative materials andnovel techniques such as layering and the use of tintsand opaque stains has led to restorations which raisesthe challenge of detecting them reliably. This in vitrostudy compared the diagnostic reliability and validityof digital imaging fibre-optic transillumination(DiFOTI – using DIAGNOcam), and fluorescenceaided identification of restorations (FAIR), with rou-tine visual and tactile examination for identifying

tooth-coloured restorations. For FAIR the approachused was illumination with 405 nm wavelength violetlight, accompanied by viewing the sample through along pass filter with a cutoff of 520 nm.Extracted human permanent teeth were mounted in

anatomical order in typodonts. Three sets of modelswere made for both maxillary and mandibular arches.Cavity preparations were done in selected teeth andthen restored with tooth-coloured resin composites,

*Australian Centre for Oral Oncology Research and Education,School of Dentistry, University of Western Australia, Nedlands,Western Australia, Australia.†Harvard School of Dental Medicine, Brigham and Women’sHospital, Boston, Massachusetts, USA.‡UQ Centre for Clinical Research, The University of Queensland,Brisbane, Queensland, Australia.Email: camile.farah@uwa.edu.au

© 2017 Australian Dental Association S11

Abstracts

ceramics and hybrid restorative materials such asormocers, Vita EnamicTM (resin reinforced ceramics)and resin reinforced glass-ionomer types of cement.The models were then mounted in a phantom headdental mannequin. Four examiners identified andcharted tooth-coloured restorations in three sets oftypodonts on the bench using conventional visual andtactile examination, DiFOTI and FAIR. All examina-tions were repeated after four weeks. Sensitivity andspecificity were calculated, as well as analyses forintra- and inter-examiner variations.

Both the sensitivity (95%) and specificity (97%) ofthe FAIR method were significantly higher than thosefor DiFOTI (82% and 82%) and conventional inspec-tion (71% and 82%). Likewise, the positive and nega-tive likelihood ratios for the FAIR method (32.66 and0.08) were superior to DiFOTI (4.84 and 0.2) andconventional inspection (4.81 and 0.41).When compared to conventional examination and

DiFOTI using near infrared light, the FAIR methodperformed better and was more reliable for identifyingtooth-coloured restorations. This method is simple toperform and time-efficient, making it well suited touse in both clinical and forensic situations.This study was supported by Grant 83-2015 from

the Australian Dental Research Foundation. The useof extracted teeth for this study was approved bythe Institutional Human Research Ethics Committee(approval number H15/03-035).

The finding of this research was presented at theInternational Association for Dental Research (IADR)ANZ meeting in Adelaide, Australia, September 2017.

Fluorescence properties of tooth-coloured restorative materials assessedusing a fluorescence DSLR cameraR Kiran,* J Chapman,* M Tennant,† A Forrest,‡ LJ Walsh§

Conventional methods of detecting tooth-colouredrestorations such as direct vision and radiographicexamination pose certain challenges in identifying therestorations that mimic the optical properties of toothstructure. Light in the ultraviolet and visible violetrange has been found useful for detection of resinrestorations based on the difference in the fluorescenceproperties of tooth-coloured restorative materials andnatural tooth structure. In the past, high-intensity flu-orescent light sources and lasers have been used foreliciting such fluorescence. However, due to size andhigh cost, their use was limited. This study comparedthe fluorescence properties of dry and wet samples ofcontemporary tooth-coloured restorative materialsusing a fluorescence based digital single-lens reflex(DSLR) camera and a variety of LEDs emitting differ-ent wavelengths of visible light as excitation sources.Sample discs of 2 mm thick and 10 mm in diameter

were prepared from 27 selected tooth-coloured restora-tive materials, including resin composites; ceramics andhybrid restorative materials such as ormocers, VitaEnamic™ and resin reinforced glass-ionomer cements.The prepared samples (both in the dry and wet states)were photographed in a standardized manner with aDSLR camera fitted with a 60 mm macro lens in a darkenvironment illuminated by the various LEDs

(405–670 nm), in combination with clear, orange andyellow filters. The levels of fluorescence for each sampleunder different combinations of incident light wave-lengths and filters was analyzed by using histogramdata for colour channels from Adobe Photoshop soft-ware. The statistical analysis for a given material com-pared the influence of moisture (dry versus wetsamples), the choice of wavelengths of light used forexcitation, and the effects of filters.Fluorescence patterns were influenced by water

sorption of the materials. UV-A/Violet light (405 nm)produced the greatest range of luminosity values(10–204) amongst the tooth-coloured restorative mate-rials, and showed the greatest differences betweenrestorations and tooth structure. The best filter combi-nations with violet light were orange or yellow filters.Under ultraviolet excitation, Fuji VIII A2 exhibited aunique bright pink fluorescence emission, while VITAEnamic™, ormocer and glass-ionomer cements emittedbluish-pink fluorescence emissions.In conclusion, the results of this study suggest that

fluorescence based photography may be a usefuladjunct for recognizing types of tooth-colouredrestorations restorative materials. A fluorescence tech-nique could be employed in routine dental examina-tion as well as for forensic identification purposes.

*School of Medical and Applied Sciences, Central QueenslandUniversity, Bruce Highway, Rockhampton, Queensland, Australia.†International Research Collaborative, Oral Health and Equity,School of Anatomy, Physiology and Human Biology, The Universityof Western Australia, Crawley, Western Australia, Australia.‡School of Natural Sciences, Nathan Campus, Griffith University,Nathan, Queensland, Australia.§School of Dentistry, The University of Queensland, Oral HealthCentre, Herston, Queensland, Australia.Email: r.kiran@cqu.edu.au

S12 © 2017 Australian Dental Association

Abstracts

Certain restorative materials such as VITA Enamic™,ormocers and glass-ionomer cements exhibit uniqueemission patterns, which makes their presence readilyapparent.This study was supported by Grant 83-2015 from the

Australian Dental Research Foundation. The authors

thank 3M ESPE, Voco, One Dental and Herculite forproviding some of the dental materials used in thestudy. The use of extracted teeth for this study wasapproved by the Institutional Human Research EthicsCommittee (approval number H15/03-035).The findings of this research was presented at the

International Association for Dental Research (IADR)ANZ Meeting, Adelaide, SA, Australia, September2017.

Publication: Kiran R, Chapman J, Forrest A, TennantM, Walsh LJ. Forensic applications: Fluorescenceproperties of tooth-coloured restorative materialsusing a fluorescence DSLR camera. Forensic Sci Int.2017; 273: 20–8.

The effect of immune genetic variants on chemotherapy-inducedgastrointestinal toxicity (CIGT) risk in patients receiving 5-fluorouracilSK Korver,* IA Ball,* RJ Gibson,*† RM Logan,‡ CS Karapetis,§ DM Keefe,¶ JM Bowen,*

JK Coller*

Oral complications of cancer therapy are expensive andimpede optimal delivery of therapy leading to pooreroutcomes. Importantly, the presence of any grade oforal mucositis, the most common dose-limiting oralcomplication, is associated with a decrease in quality oflife scores and can impair speaking, swallowing andalimentation. Fluoropyrimidines, 5-fluorouracil (5-FU)and capecitabine, are highly mucotoxic, with up to18% of patients at risk of severe oral mucositis. Theunderpinning mechanism of this response is an increasein pro-inflammatory cytokine expression, includinginterleukin-1 beta (IL-1b) via the toll-like receptor 2/4(TLR2/4) signalling pathway. Our pilot study showedthat genetic variability in TLR2 and TNFA can predictthe risk of severe toxicity. However, there are nomatching diagnostic phenotypic markers to predict tox-icity risk in patients. This study aimed to determine ifthe pro-inflammatory secretory response (IL-1b andTNF-a) from isolated peripheral mononuclear bloodcells (PBMCs) can act as a diagnostic phenotypicmarker to predict the incidence of severe toxicity inparticipants following 5-FU or capecitabine treatment;and if IL-1B, TNFA, TLR4 and TLR2 genotypes are

associated with IL-1b and TNF-a secretory responses,respectively.Seventeen participants (seven with severe toxicity)

were recruited, with their toxicity data (based on NCICTCAE version 4), demographics and treatmentparameters collected from case note review andgenetic variability in IL-1B, TNFA, TLR4 and TLR2determined by custom genotyping. Ex vivo quantifica-tion of TLR2 and TLR4 agonist-induced stimulationof IL-1b and TNF-a secretion by PBMCs was deter-mined by enzyme-linked immunosorbent assays(ELISAs). Delta and fold changes in secretion weredetermined, with these parameters compared betweenthe two participant groups, severe toxicity and no/mild toxicity, using t-tests. In addition, the associationbetween IL-1B, TNFA, TLR4 and TLR2 genotypesand IL-1b and TNF-a secretion was also examinedusing t-tests.There were no differences in TNF-a and IL-1b secre-

tion between the two participant groups. There was anincreased expression of TLR4-stimulated IL-1b secre-tion in participants with the IL-1B rs1143634 (+3954C > T) genotype (P = 0.048). No other impact ofgenetic variability on cytokine secretion was observed.This study is ongoing. Further participants are

being recruited to expand the study cohort to 46,allowing a two-fold change between TNF-a and IL-1bto be adequately detected.

This abstract is based on research funded by an Aus-tralian Dental Research Foundation Project Grant.

*School of Medical and Applied Sciences, Central QueenslandUniversity, Bruce Highway, Rockhampton, Queensland, Australia.†International Research Collaborative, Oral Health and Equity,School of Anatomy, Physiology and Human Biology, The Universityof Western Australia, Crawley, Western Australia, Australia.‡School of Natural Sciences, Nathan Campus, Griffith University,Nathan, Queensland, Australia.§School of Dentistry, The University of Queensland, Oral HealthCentre, Herston, Queensland, Australia.Email: r.kiran@cqu.edu.au, j.chapman@cqu.edu.au

*Adelaide Medical School, University of Adelaide, Adelaide, SouthAustralia, Australia.†Division of Health Sciences, University of South Australia,Adelaide, South Australia, Australia.‡Adelaide Dental School, University of Adelaide, Adelaide, SouthAustralia, Australia.§Flinders Medical Centre, Bedford Park, South Australia, Australia.¶Royal Adelaide Hospital, Adelaide, South Australia, Australia.Email: richard.logan@adelaide.edu.au

© 2017 Australian Dental Association S13

Abstracts

Maternal and perinatal factors associated with early childhood cariesKG Peres

Although many biological, behavioural and social riskindicators for early childhood caries (ECC) have beenstudied, more effort is needed to identify other con-tributing factors or causal mechanisms related to thiscommon disease.To investigate if maternal characteristics and peri-

natal factors are associated with ECC.A case-control study (n = 1720) was carried out with

cases and controls selected from the South AustralianDental Service (SADS) database including patients agedtwo to four years who attended SADS from February toJune 2016. All (n = 860) cases (dmfs >0) from onemonth were included and one control (dmfs = 0) percase was randomly selected from the same month. Aquestionnaire for parents or caregivers included preg-nancy, perinatal and socioeconomic information. Mul-tivariable regression analysis was performed to identifyrisk factors for ECC.

The response rate was 27.5% (n = 473). The chanceof having ECC was 50% greater among children whowere born from a caesarean delivery (OR = 1.5 [95%CI 1.0; 2.3]), 90% greater among those whose motherdid not receive any prenatal or perinatal care(OR = 1.9 [95% CI 1.0; 3.5]) and 3.3 times higher inchildren whose mothers suffered from gestational dia-betes (OR = 3.3 [95% CI 1.3; 8.5]). These resultswere found after adjustment for socioeconomicvariables.Findings from this study may subsidise dental ser-

vices working together with general health profession-als in order to strategically plan health policies takinginto account the common risk approach for oral andgeneral diseases.

Our thanks to the International College of Dentists –Australasian Section for the ICD Award, and to theSouth Australian Dental Service. The author gratefullyacknowledges the support of the Australian DentalResearch Foundation.

Assessment of mandibular canal clarity using two-dimensional (2D) andthree-dimensional (3D) radiographic imagesK Shah,* E Ports,* R Yong,* S Mihailidis,* A Brook,*† P Anderson,‡§ G Townsend,*

S Ranjitkar*

Precise location of the mandibular canal is importantto avoid neurovascular injury and its complications,including paraesthesia, hypoesthesia, or dysesthesiaduring surgical procedures such as implant placement,orthognathic surgery and tooth extraction. Localiza-tion of the mandibular canal is usually based on iden-tification of radiopaque lines in radiographic images.The latest multi-detector computed tomography(MDCT) technology has the advantage of producingclearer images of the mandibular canal than cone-beam computed tomography (CBCT). Therefore, theaims of this study were to compare the clarity of themandibular canal in 2D periapical images with 3DMDCT images at resolutions of 300 and 100 lm andto correlate cadaver dissections to radiographic fea-tures.A total of 15 cadaver heads were subjected to 2D

periapical radiography at 50 lm (Planmeca Intra Unit,Helsinki, Finland) and 3D MDCT scanning at 300and 100 lm resolution (Philips Ingenuity 128

Scanner, Andover, USA). The mandibular canals inboth 2D and 3D images were categorized into ante-rior, middle and posterior thirds between the mentaland mandibular foramina. Mandibular canal claritywas scored as clear, semi-clear and unclear. The cada-ver specimens were decalcified in 5% nitric acid solu-tion and dissected to expose the mandibular canal.There was an overall significant effect of location

(P < 0.001) and also imaging modality on mandibularcanal clarity (P < 0.001) based on Friedman tests.Post-hoc Wilcoxon sign rank sum tests adjusted formultiple comparisons showed significantly greatercanal clarity in the posterior mandibular third com-pared to the anterior and middle thirds (P < 0.01) aswell as significantly greater canal clarity in 3D100 lm images (P < 0.01) when compared to 2Dimages. Trifid canals found in cadaver dissectionswere not observed radiographically and simple neuralbranching was observed as short radiopaque linesfrom the mandibular canal in 2D and 3D

The University of Adelaide, Adelaide, South Australia, Australia.Email: karen.peres@adelaide.edu.au

S14 © 2017 Australian Dental Association

Abstracts

radiographic images. An unclear canal in 2D radio-graphs was associated with continuity of cancellousbone around the mandibular canal in the cadaverspecimens.Mandibular canals were clearer in the posterior

third compared to the anterior and middle thirds inboth 2D and 3D images. MDCT imaging at 100 lmresolution showed greater mandibular canal claritywhen compared with 2D radiographs. However, thepresence of a large proportion of unclear mandibularcanals, even at the 100 lm resolution, emphasises theneed for further technological advancements inlocating the mandibular canal for craniofacial applica-tions.

This project was supported by the Australian Den-tal Research Foundation Undergraduate ResearchScholarship. The authors would like to acknowledgeDrs Bill Loftus and Ben Wigmore from Sound Radiol-ogy, Glenside for assistance with CT imaging, MrGrant Gully from Flinders University for assistancewith MIMICS software, Messrs Michael Hodges andCory Lloyd from the Ray Last Anatomy Laboratoriesfor providing access to cadaver specimens, and DrKojiro Takazawa for assistance with dissection.

The findings of this research were presented at theAustralia New Zealand (ANZ) Colgate Poster Com-petition, 94th General Session and Exhibition of theInternational Association for Dental Research(IADR), Seoul, Republic of Korea, June 2016; theColgate Research Day, Adelaide Dental School, SA,Australia, July 2016; the Beacon Conference forUndergraduate Research, University of Adelaide, SA,Australia, August 2016.

Effect of local delivery of VEGF-Hydrogel on BRONJ lesion and local geneexpression in rat model – an in vivo and in vitro studyD Sharma,* S Hamlet,† E Bogdan Petcu,‡ S Ivanovski†

BRONJ was considered to be due to direct suppres-sion of bone remodelling and cytotoxic effects of zole-dronic acid (ZA) on bone and oral mucosal cells.However, recent literature suggests that suppressedangiogenesis contributes significantly to the pathogen-esis of this condition. This in vitro and in vivo studyexamined the effect of locally delivered VEGF-hydro-gel and local gene expression in rat BRONJ model.In vitro release study with 200 ng of rat VEGF-165

(Biovision) loaded into 500 lL hydrogel (Hystem-HP)prior to cross-linking and incubated in release mediathat was sampled and quantified using ELISA, over 28-days. In vivo, a BRONJ model using Sprague-Dawleyrats was established by weekly intraperitoneal injectionof ZA (three weeks), followed by extraction of maxil-lary first two molars and creation of a 5 mm defectwhich received either VEGF-containing hydrogel, HAgel alone or no gel. ZA was continued for four weekspost-surgery, prior to sacrifice. Gross examination,micro-CT evaluation and histological assessment wasconducted to evaluate the effect of VEGF local delivery.Histological assessment involved quantification ofosteonecrotic areas, total vascularity (von WillebrandFactor, vWF immunostaining) and specifically, themicrovessel density (CD105 immunostaining). Further-more, to assess molecular level changes during bone

and soft tissue healing, gene expression analysis wasconducted on the bone and gingival tissue samples fromdefect area.Gross and micro-CT evaluation of the lesion

showed significantly reduced osteonecrosis in the pres-ence of VEGF. Histomorphometric assessment ofosteonecrosis showed significantly higher areas ofnecrotic bone (empty lacunae) in no gel animals com-pared to the VEGF treated group (71648 � 6785 lm2

vs 11919 � 2920 lm2, P < 0.0001). Also, total vas-cularity (vWF immunostaining) was significantlyhigher in the VEGF gel group (577.026 � 60.25 lm2)compared to the no gel group (139.87 � 23.22 lm2,P < 0.0001) suggesting a positive role of VEGF gel ontotal vascularity. Furthermore, neovascularization(CD105 immunostaining) was significantly improved(393.4 � 36.52 lm2), in comparison to gel alone(102.68 � 10.97 lm2; P < 0.0001) and control group(68.68 � 17.06 lm2; P < 0.0001). Gene expression ofvascular (vWF, VEGF-R1, VEGF- R2 and CD105),inflammatory (IL-1b and TNF-a) and bone specificmarkers (OCN, TRAP and ALP) in the defect areawas also significantly skewed towards enhanced heal-ing, in the presence of locally-delivered VEGF sup-porting the positive effect of VEGF, within a healingextraction socket.

*School of Dentistry, The University of Adelaide, Adelaide, SouthAustralia, Australia.†Dental Institute, Queen Mary University of London, London, UK.‡Women’s and Children’s Hospital, Adelaide, South Australia,Australia.§Australian Craniofacial Unit, Adelaide, South Australia, Australia.Email: kshah.1593@gmail.com

© 2017 Australian Dental Association S15

Abstracts

Anti-resorptive agents, specifically ZA affect localangiogenesis by its inhibitory effect on vasculature,including neoangiogenesis. Based on the above results,

sustained-local delivery of VEGF can be employed asa valuable preventive modality in susceptible patientsrequiring dental manipulation, while on anti-resorptivemedications.This abstract is based on research funded entirely

by the Australian Dental Research Foundation Grant(No. 77-2015).

The findings of this research was presented at Interna-tional Dental Research Foundation (IDRF) GeneralSession at Seoul, Republic of Korea in June 2016.

Cytokine profiles in serum and placenta of pregnant mice followingexperimentally induced periodontitisK Tian,* M Macowan,† TR Fitzsimmons,* CT Roberts,‡ PS Zilm*

Numerous studies have been conducted to define thepotential association between maternal periodontitisand adverse pregnancy outcomes. Normal pregnancyis a physiologically stressful state with increasedinflammatory activity which may be enhanced by peri-odontitis.This may be associated with elevated blood pressure,

increased perfusion of the placenta and enhanced foetalgrowth. We hypothesize that mice with alveolar boneloss have elevated blood glucose concentrations whichenhance foetal growth possibly due to sub-clinical sys-temic inflammation associated with periodontitis. Theobjective was to measure cytokine profiles includinginflammatory mediators such as C-reactive proteinfrom the serum of control and experimental mice withinduced periodontitis and assess pregnancy outcomes.Ethics approval was obtained from the University

of Adelaide Animal Ethics Committee. The intra-venous injection and the murine periodontitis modelswere adapted from our published protocols. Periodon-titis was induced in pregnant mice using an inoculumof Fusobacterium nucleatum and Porphyromonas gin-givalis. In parallel, another group was injected withF. nucleatum intravenously into the circulatory sys-tem. At day 18 of gestation, pregnancy outcomes wererecorded and inflammatory mediators assessed. Alveo-lar bone loss was assessed using micro-CT. Serum col-lected at day 18 of pregnancy was analyzed for KC,IL-1b, IL-6, IL-33, TNF-a, RANKL, IL-10 and LIXusing a Magnetic Luminex� screening according tothe manufacturer’s protocol. Mouse C-Reactive

Protein was measured in serum using a commerciallyavailable enzyme linked immunosorbent assay.Periodontitis was confirmed by an increased distance

between the cemento-enamel junction and alveolarbone crest. However, there was no significant increasein circulating CRP levels in the injected group.We successfully induced alveolar bone loss in our

induced murine periodontitis model. A significantincrease in foetal and placental weights were observedin mice with periodontitis. No other significantadverse outcomes were observed.There was no significant difference in IL1b and LIX

concentrations amongst the comparison groups. CRPlevels were not significantly different between preg-nant mice with experimentally induced periodontitisand controls. Despite inducing alveolar bone loss, weobserved no significant difference in RANKL concen-trations between our periodontitis/pregnant and con-trol pregnant/groups. RANKL concentration wassignificantly lower in pregnant groups irrespective ofperiodontitis status. IL-33 concentration was signifi-cantly lower in the periodontitis/pregnant comparedto the pregnant controls.This study found significant changes in pregnancy

outcomes after the induction of periodontal diseaseand this was not associated with significant changesin the serum concentration of KC, IL-1b, IL-6, IL-33,TNF-a, RANKL, IL-10 and LIX. IL-33 has an impor-tant role in the induction and modulation of immuneresponses suggesting a potential association of IL-33in response to periodontal pathogens.We acknowledge funding for this project from the

Australian Dental Research Foundation and a studentresearch scholarship for Ms Tian.

This research was presented at a talk at the AustralianHealth and Medical Research Institute on 20 October2016.

*Department of Periodontics, College of Medicine and Dentistry,James Cook University, Cairns, Queensland, Australia.†Menzies Health Institute Queensland, School of Dentistry andOral Health, Griffith University, Gold Coast Campus, Queensland,Australia.‡Menzies Health Institute Queensland, School of Medicine, GriffithUniversity, Gold Coast Campus, Queensland, Australia.Email: dileep.sharma@griffithuni.edu.au, s.ivanovski@griffith.edu.au

*Adelaide Dental School, The University of Adelaide, Adelaide,South Australia,Australia.†School of Biological Science, The University of Adelaide, Adelaide,South Australia,Australia.‡Research Centre for Reproductive Health, The University ofAdelaide, Adelaide, South Australia, Australia.Email: peter.zilm@adelaide.edu.au

S16 © 2017 Australian Dental Association

Abstracts

How do Australian community pharmacists and pharmacy assistantsmanage non-healing mouth ulcer presentations and do they refer?BJ van Rensburg,* CR Freeman,* PJ Ford,† MW Taing*

Diagnostic delay in patients with oral cancer can leadto poorer prognosis. Oral cancer may present as apersistent lump, soreness in the oral cavity or non-healing ulcer. Community pharmacy staff play animportant role in the early detection and preventionof potentially neoplastic oral lesions given patientsregularly visit pharmacies with enquiries relating tooral lesions and ulcers. Professional practice guidelinesrecommend ulcers persisting longer than 2–3 weeksrequire specialist input into their management. There-fore, referral without delay to a general or dentalpractitioner is required. This project evaluated thecurrent management and referral of non-healingmouth ulcer presentations in Australian communitypharmacies in the Greater Brisbane region.Approval for the study was obtained by Bellberry

Human Research Ethics Committee in March 2016(approval no. 2016-01-029). Trained standardizedmystery shoppers visited 220 randomly selected com-munity pharmacies within the Greater Brisbane regionbetween March and May 2016. The mystery shoppersenacted two standardized over-the-counter (OTC)non-healing (>1 month) mouth ulcer scenarios: Adirect product request (DPR) (n = 110) and a symp-tom based request (SBR) (n = 110). After each inter-action, results were documented and evaluated againstAustralian national pharmacy professional practicestandards. Referral rates for pharmacy staff (pharma-

cist, pharmacy assistant or mixed – pharmacist andassistant) handling the interactions were also assessedand results analyzed using SPSS software.Australian pharmacy practice standards recommend

pharmacy staff ask six key questions during SBR andDPR consultations to enable informed decision mak-ing regarding appropriate treatment/advice. Questionsrelating to identifying the patient (76.4%; 168/220)and their symptoms (68.6%; 151/220) were asked bypharmacy staff in the majority of interactions. Theremaining four questions relating to other medica-tions, treatments tried, other medical conditions andsymptom duration were asked in 52.7% (116/220),32.3% (71/220), 30.5% (67/220) and 27.3% (60/220)of interactions respectively. Mystery shoppers werereferred to the doctor/dentist in 11.8% (26/220) of allinteractions.Generally, community pharmacy staff management

of non-healing mouth ulcer consultations in this studydid not comply with national professional standards. Inparticular, infrequent questioning about the duration ofthe non-healing mouth ulcer is likely to have resulted inlow referral rates by staff. This study identifies the needfor increased oral cancer education and awareness forcommunity pharmacy staff, in addition to practisingaccording to professional standards to effectively screenfor potentially neoplastic mouth lesions.

This research was funded by an Australian DentalResearch Foundation Research Grant. Additionally,we would like to thank the mystery shoppers onwhom the study relied; and the School of Pharmacy,The University of Queensland for the provision ofresources supporting this project.

Comparison of different guided bone regeneration membranes in healthyand osteoporotic sheepC Vaquette,* M Tavazoei,† DW Hutmacher,* S Ivanovski†

The objectives of this study were to assess new occlu-sive membranes made of medical grade polycaprolac-tone (mPCL) electrospun fibres for application inguided bone regeneration (GBR) and to compare themto the gold standard Biogide.Three different GBR membranes were assessed: (i)

electrospun mPCL; (ii) Polystyrene sodium sulfonate

grafted electrospun mPCL (NaSS-PCL, a bioactivepolymer known to promote osteogenesis); and (iii)Biogide. The electrospun membranes were fabricatedby solution electrospinning using an in-house builtspinner. The electrospinning process was performedonto a flat collector surface, which resulted in the for-mation of randomly orientated fibres. The PCL

*School of Pharmacy, University of Queensland, Brisbane,Queensland, Australia.†School of Dentistry, University of Queensland, Brisbane,Queensland, Australia.Email: m.taing@uq.edu.au

© 2017 Australian Dental Association S17

Abstracts

electrospun membranes are highly flexible and resili-ent when folded. This membrane was shown to havea fibre diameter of 3 lm, a small pore size from 5 to10 lm and therefore is partially occlusive. The regen-erative potential of these membranes at four weeksand six weeks were assessed in an ovine mandibledefect in healthy and osteoporotic animals (n = 3 foreach group at each time point). The osteoporotic ani-mals underwent a hypothalamo-pituitary axis discon-nection for triggering osteoporosis and were housedfor an additional 15 months in order to establish thecondition. Thereafter, the animals were placed undergeneral anesthesia and surgical access was initiated byperforming a midline incision in the platysma muscle.Blunt dissection of the tissues was performed until theinferior border of the mandibular bone was exposed.Periosteum was incised and elevated in order to accessinferior third of lateral aspect of each hemi-mandiblefor the creation of proposed surgical defects. Undercontinuous coolant sterile saline irrigation, a trephineburr with 8 mm external diameter was used at800 rpm to create the osseous defects limited in the

thickness of the cortical bone. The regenerative out-come towards bone formation was assessed by micro-computed tomography and histomorphometry usingtoluidine stained slides.Histology revealed bone formation as early as four

weeks post-implantation; the newly formed bone waslocated mostly in the direct vicinity of the defect wallsregardless of the membrane used for GBR or the ani-mal condition (healthy or osteoporotic). At six weekspost-implantation, more bone was observed in thedefects for the three different groups, in some cases,with full bridging for the three different groups.Quantification of bone formation using two differenttechniques (histomorphometry and lCT) revealedthere were no fundamental differences in the healingpattern between the three membranes, indicating thatthey performed equally. In addition, there was no sta-tistical difference between healthy and osteoporoticanimals despite a higher percentage of bone fill asseen per histomorphometry in the control groups.This work demonstrates that the utilization of

mPCl, NaSS-PCL and the gold standard Biogide mem-brane did not differ significantly for bone formationin healthy and osteoporotic sheep. Hence the syntheticmPCL, NaSS-PCL membrane is a potential alternativeto the utilization of xenogenic collagen membrane.

This abstract is based on the work funded by theAustralian Dental Research Foundation.

The influence of slime/capsule on biofilm formation in response totetracycline and sodium hypochlorite by clinical isolates of EnterococcusfaecalisA Yoo,* G Rossi-Fedele,* SP Kidd,† AH Rogers,* PS Zilm*

Root canal treatment (RCT) relies on antimicrobials(bleach) to kill bacteria that infect the tooth. We haveshown that bleach can induce biofilms in Enterococ-cus faecalis, bacteria often found to resist RCT. Bio-films make bacteria more difficult to kill and isassociated with the production of an extracellular coat(ECM). We aimed to determine if biofilms and ECMproduction was increased in the presence of bleach.Results showed that some E. faecalis strains increasedECM and biofilm growth in low levels of bleach. Weconclude that this may aid the organism’s survivalduring RCT.Frequently, E. faecalis is identified from previously

root-filled teeth. An extracellular material (ECM)layer surrounding E. faecalis may play a role inincreasing the organism’s resistance to stresses

experienced during root canal treatment and mayexplain the varying treatment success rates. Therefore,the aim was to determine whether ECM is up ordown-regulated by E. faecalis in response to sub-minimal inhibitory concentrations (sub-MIC) ofsodium hypochlorite (NaOCl) and determine itsimpact on biofilm development.A crystal violet biofilm assay protocol optimised for

E. faecalis was performed on 37 strains to screen fortheir ability to produce biofilms and strains wereranked as strong (OD570 nm ≥ 0.55) or poor(OD570 nm ≤ 0.16). An unpaired, two tailed, t testwas used to determine statistical significance(P < 0.05) and 15 strains were selected: 10 strong andfive poor biofilm producers. Biofilm assays were per-formed on all strains when subjected to a sub-MIC of

*Queensland University of Technology, Brisbane, Queensland,Australia.†Griffith Health Institute, School of Dentistry and Oral Health,Griffith Health Institute, Griffith University, Southport, Queensland,Australia.Email: cedryck.vaquette@qut.edu.au

S18 © 2017 Australian Dental Association

Abstracts

NaOCl. All strains were screened for ECM by grow-ing on Congo red agar (72 hours at 37°C) under aero-bic conditions (controls) and with sub-MIC levels ofNaOCl. ECM production was confirmed using a scan-ning electron microscope (SEM). Single blinded assess-ments by independent assessors were used to scorechanges in ECM production.In optimal growth conditions, ECM was expressed

in all strains.In the presence of sub-MIC of NaOCl, of the 10

strong biofilm producers, SEM analysis indicated thatfive isolates increased their ECM production but onlythree of these showed increased biofilm growth. Two

strains decreased ECM production and showeddecreased biofilm growth. Three isolates demonstratedno observable changes in ECM production or biofilmgrowth.All non-biofilm producers demonstrated no observ-

able changes in ECM production although one strainincreased biofilm growth.Clonal diversity amongst strains of E. faecalis sug-

gests that some strong biofilm producers can up-regu-late ECM production and increase biofilm growth inresponse to sub-MIC concentrations of NaOCl. Thismay aid the organism’s survival during root canaltreatment.The researchers acknowledge funding from the Aus-

tralian Dental Research Foundation for this project.

The findings from this research were presented at the94th General Session and Exhibition of the Interna-tional Association for Dental Research Seoul, TheRepublic of Korea, June 2016.

Effect of matriptase on lymph node mast cell accumulation after UVexposureS Basha, NMM Hassan

Matriptase is a membrane bound serine proteaseexpressed in most epithelial tissues under physiologicconditions, and whose expression has been linked tooral cancer progression. Mast cells are best known fortheir immune functions, however there is evidence thatmast cell aggregation in skin and draining lymph nodesmay play a crucial role in immune suppression follow-ing UV irradiation, a key event in squamous cellcarcinogenesis. Mast cell activation is also triggered byPAR-2, a putative substrate of matriptase. The aim ofthis study is to determine whether lack of matriptasehas an effect on lymph node mast cell accumulationafter chronic exposure to UV radiation in mice.We exposed matriptase hypomorphic and wild type

C57BL/6 female mice to a bank of UVA and UVBemitting fluorescent tubes (250 mJ/cm2 and accompa-nying UVA to mimic solar UV) for 25 weeks. Concur-

rently, a control group of matriptase hypomorphicand wild type C57BL/6 female mice were raised for25 weeks in the absence of UV treatment. Sections ofdorsal trunk lymph nodes were stained in an H&Eand toluidine blue staining protocol to allow for identi-fication of mast cells. Intergroup comparisons in mastcell density were analyzed using one-way ANOVAwith multiple comparisons with Bonferroni’s correction(Prism 7; GraphPad Software Inc, San Diego, USA).A four-fold reduction in lymph node mast cell den-

sity (MCD) was observed between irradiated hypo-morphic and wild type mice. A five-fold reduction inlymph node MCD was observed between hypomor-phic irradiated and non-irradiated mice.Lack of matriptase appears to inhibit mast cell

accumulation in lymph nodes.

Funding for this study was provided by the AustralianDental Research Foundation Student Grant.

*Adelaide Dental School, The University of Adelaide, Adelaide,South Australia, Australia.†Research Centre for Infectious Diseases, School of BiologicalSciences, University of Adelaide, Adelaide, South Australia,Australia.Email: peter.zilm@adelaide.edu.au

Charles Sturt University, Orange, New South Wales, Australia.Email: simonbasha@gmail.com, nhassan@csu.edu.au

© 2017 Australian Dental Association S19

Abstracts

Extensive phenotyping of the orofacial and dental complex in CrouzonsyndromeA Khominsky,* R Yong,* S Ranjitkar,* GC Townsend,* PJ Anderson*†

Fibroblast growth factor receptor 2 (FGFR2)C342Y/+

mutation is a known cause of Crouzon syndrome,that is characterized by craniosynostosis (the prema-ture fusion of one or more cranial sutures) and a shortmidface, leading to neural, respiratory and psychoso-cial disorders. Despite orthognathic and orthodontictreatment being part of management of Crouzon syn-drome, there is limited literature as to the effects ofthe mutation on dental structures. The aim was toconduct extensive phenotyping caused by the Crouzon(FGFR2C342Y/+) mutation on maxillary, mandibularand dental morphology.Morphometric data were obtained from 40 mouse

skulls, representing two genotypes (Crouzon and wild-type) and two sexes (males and females) (n = 10 ineach group). Dental analysis further categorized thefirst molars into the two jaws (maxillary andmandibular) (n = 20 in each group). Maxillary,mandibular and dental morphology was compared byanalyzing 36 different landmark-based linear dimen-sions in three-dimensional micro-computed tomo-graphy reconstructions.Compared with wild-type, Crouzon maxillae were

significantly shorter in maximum vertical height(P < 0.05), anterior and posterior lengths (P < 0.001)and middle width (P < 0.001), but significantly largerin posterior width (P < 0.001). In the Crouzon mand-ible, the ascending and descending heights, effective

and mandibular lengths, and intercoronoid and inter-condylar widths were significantly shorter, whereasintergonial width was significantly larger (P < 0.01for intercondylar width; P < 0.001 for other compa-risons). Crouzon teeth were significantly smallermesiodistally, but larger in crown height (P < 0.001for each comparison). All Crouzon mice presentedwith bifid mandibular condyles compared to one inwild-type. Twenty-five per cent of the Crouzon sam-ple presented with expansive bone lesions in themandibular incisor alveolus compared to none inwild-type.Hypoplasia in all three planes in Crouzon maxillae

and mandibles, together with the presence of bifidmandibular condyles and expansive bone lesions, maybe relevant to maxillofacial surgery and orthodontics,and highlights that the FGFR2C342Y/+ mutation ismore complex than simply downstream effects ofsutural fusion. Beyond skeletal effects, theFGFR2C342Y/+ mutation is now implicated in affectingtooth development. This study’s skeletal phenomicsdata provides useful baseline data against which theeffect of various treatments can now be assessed.The author acknowledges the assistance of Adelaide

Microscopy with micro-CT analysis and the Women’sand Children’s Hospital (Adelaide) for housing theanimal colony. This study was supported by the Aus-tralian Dental Research Foundation and AustralianCranio-Maxillo Facial Foundation.

The findings of this research were presented at the57th Annual Scientific Meeting of the IADR ANZDivision to be held in Adelaide, South Australia, Aus-tralia, 25–27 September 2017.

Investigation of the extra-oral migration of Fusobacterium nucleatumsubspnucleatum and its role in adverse pregnancy outcomesK Tian,* R Wilson,† C Roberts,† S Kidd,‡ P Zilm*

There is increasing, nevertheless, equivocal evidencelinking gum disease to diseases elsewhere in the bodysuch as heart disease, diabetes, colorectal cancer andadverse pregnancy outcomes. Our study uses two par-allel animal models to investigate the association of a

key oral bacterium responsible for the development ofgum diseases and its ability to induce adverse preg-nancy outcomes in mice.Infection or challenge to the feto-placental unit by

oral pathogens is an important biological pathway

*Adelaide Dental School, The University of Adelaide, Adelaide,South Australia, Australia.†Australian Craniofacial Unit, Women’s and Children’s Hospital,Adelaide, South Australia, Australia.Email: alexander.khominsky@gmail.com

S20 © 2017 Australian Dental Association

Abstracts

that may result in adverse pregnancy outcomes. Ourrecently published study demonstrated that IV injec-tion of Fusobacterium nucleatum, an important bac-terium involved in periodontal disease, is able toinduce adverse pregnancy outcomes such as foetaldeath, pre-term birth and low birth weight in mice.F. nucleatum subspecies nucleatum (FNN) was theonly subspecies capable of migrating haematogenouslyto the placenta in pregnant mice.The main investigation aims were:

• Repeat results from the preliminary study usingFNN and a greater number of mice.

• Measure alveolar bone loss, an indicator of peri-odontitis, using micro-CT technology and assessadverse pregnancy outcomes.

Periodontitis was induced in pregnant mice using aninoculum of FNN and Porphyromonas gingivalis. Inparallel, FNN was injected intravenously into the cir-culatory system. At day 18 of gestation, the placenta,liver, spleen and blood were harvested and foetus size,number of viable foetuses and resorptions, maternal,foetal and placenta weights were recorded. The pres-ence of FNN and P. gingivalis was assessed by poly-

merase chain reaction, inflammatory mediators wereassessed by multiplex analysis, and fasting blood glu-cose levels were measured. For the induced periodon-titis experiment, alveolar bone loss was assessed withusing micro-CT technology.In mice who received IV injection of FNN, a signifi-

cant decrease in foetal weight (P = 0.000) and foetalplacental weight ratio (P = 0.000) was observed. Wenoted a significant increase in maternal liver, spleen,and heart weights in our experimental group(P = 0.001, P = 0.000 and P = 0.024, respectively).The increased spleen and liver weights may suggest anunderlying systemic infection. However, there was nosignificant increase in circulating CRP levels(P = 0.280) in the injected group. In parallel, we suc-cessfully induced alveolar bone loss in our inducedmurine periodontitis model. In the pregnant micechallenged with FNN and P. gingivalis, we observed asignificant increase in foetal weight (P = 0.049) and asignificant increase in placental weight (P = 0.002).No other significant adverse pregnancy outcomes wereobserved. Polymerase chain reaction analysis ofmaternal organs and placentas did not identify FNNin any extracted tissues.Periodontitis in mice elevated foetal and placental

weight. Based on the induced periodontitis model, thepresent study does not directly support the causal roleof FNN in the association between periodontitis andadverse pregnancy outcomes.

The researchers acknowledge partial funding for thisproject by the Australian Dental Research Founda-tion.

The effect of incident beam angle and horizontal distance of the light-curing unit on the degree of polymerisation in photo-initiated compositeresin dental restorative materialsCY Yang,* MJ Liddell,† EA Jennings,‡ P Buttner,§ N Meredith‡

Despite extensive studies on factors influencing thequality of composite resin formed through photo-polymerization, there remains inadequate informa-tion regarding the effect of varying incident beamangle and horizontal distance of the light curingunit tip from the resin surface. The aim ofthe study was to evaluate the influence of these fac-tors on the degree of conversion in compositeresins.

The degree of conversion of three different types ofcomposite resin (nanohybrid, bulk-fill, flowable) wasevaluated at seven incident beam angles (0, 15, 20,30, 40, 45, 60°) and five horizontal curing distances(0, 2, 4, 6, 8 mm). The degree of conversion wasdirectly measured by the Fourier Transform Infra-Redspectroscopy.The degree of conversion of each resin decreased as

the incident angle increased from 0 to 60° with

*School of Dentistry, University of Adelaide, Adelaide,South Australia, Australia.†School of Medicine & Robinson Research Institute, University ofAdelaide, Adelaide, South Australia, Australia.‡Research Centre for Infectious Diseases, School of BiologicalSciences, University of Adelaide, Adelaide, South Australia,Australia.Email: peter.zilm@adelaide.edu.au

© 2017 Australian Dental Association S21

Abstracts

optimum curing below 30°. The degree of conversionof each resin decreased as the horizontal distanceincreased from 0 to 8 mm with optimum curingbelow 2 mm.

For optimum photo-initiated curing of compositeresins, the light curing unit curing coordinate triangle is:

• Tip <30° from vertical orientation to resin surface

• Tip <2 mm horizontally from the centre of resinsurface

• Tip <6 mm vertically from resin surface

The authors would like to acknowledge the generoussupport of Kerr Australia Pty Ltd, Robert Ennis-Thomas for assistance in the experimental set-up andJames Cook University and the Australian DentalResearch Foundation for financial assistance.

*James Cook University, Cairns, Queensland, Australia.†Discipline of Chemistry, Australia and College of Science andEngineering, Division of Tropical Environments and Societies,James Cook University, Cairns, Queensland, Australia.‡College of Medicine and Dentistry, Division of Tropical Healthand Medicine, James Cook University, Cairns, Queensland,Australia.§Biostatistics and Epidemiology, Centre for Chronic DiseasePrevention, James Cook University, Cairns, Queensland, Australia.Email: michael.liddell@jcu.edu.au

S22 © 2017 Australian Dental Association

Abstracts