1

IMPACT OF MARGINAL CONTACT OF REMOVABLE

ACRYLIC PARTIAL DENTURES ON PERIODONTAL

PARAMETERS

Rasika Manori Jayasingha*

Aruni Tilakaratne**

Najith Amarasena***

Florian Mack****

Thillaiampalam Anandamoorthy**

*Teaching Hospital, Kurunegala

**Faculty of Dental Sciences

University of Peradeniya

Peradeniya, Sri Lanka

***School of Dentistry, University of Adelaide, Adelaide, Australia

**** School of Dentistry and Oral Health

Griffith University, South Port, Australia

Correspondence

Dr. R.M.Jayasingha, Consultant in Restorative Dentistry, Teaching Hospital, Kurunegala

Sri Lanka

Tel: 0094777806314 E mail: manoripathiraja@yahoo.com

ABSTRACT

2

AIM

to assess the periodontal parameters, plaque score, bleeding on probing, probing pocket depth, gingival

recession and loss of attachment of teeth in contact with removable partial dentures and to compare

them with teeth in the contra lateral side of the same arch not in contact with the acrylic resin base.

METHODS

Sample consisted of 46 partially edentulous patients. Maxillary acrylic partial dentures which were

designed as the gingival margin of two teeth on one side of the arch was in contact with the acrylic

resin base (control side). The same teeth on contra lateral side of the arch were kept relieved from the

denture base. Initial periodontal assessment with plaque score (PLS), bleeding on probing (BOP),

probing pocket depth (PPD), gingival recession (GR) and loss of attachment (LOA) was carried out.

All patients were periodontally assessed after denture insertions.

RESULTS

Measurements for periodontal parameters were increased significantly at 3 and 6 months of denture

wearing in the control side. The changes of all parameters in the test side were not significant.

CONCLUSIONS

Acrylic partial dentures tend to adversely affect periodontal parameters when teeth are in contact with

resin base. This effect is increased with longer duration of RPD wear.

KEY WORDS: bleeding on probing, periodontal parameters, plaque score, probing pocket depth,

removable partial dentures

3

INTRODUCTION

Removable partial dentures (RPDs) are

considered a widely accepted means of

replacing missing natural teeth thereby

restoring function and aesthetics in partially

edentulous patients.1 Although other options

are available, such as fixed prosthesis and

implant-retained-overdentures, RPDs still play

a major role in prosthetic rehabilitation owing

to financial issues, patient compliance and

residual height of edentulous ridges.2,3. In

South East Asian countries such as Sri Lanka,

RPDs are still considered the main treatment

modality for replacement of missing teeth.

Since RPDs are at least partially

supported/retained by remaining natural teeth,

various studies have been carried out in order

to assess their effects on periodontal health,

especially plaque accumulation, gingival

inflammation, mobility, pocket depth and bone

loss.4,5 Carlsson et al in their 4-year

longitudinal study investigated abutment teeth

associated with partial dentures, found an

increased incidence of gingival inflammation,

deepened gingival pockets, mobile abutment

teeth, alveolar bone loss and dental caries

compared to the base line.6 Yeung et al in their

study of cobalt-chromium RPDs, reported a

significant increase in the prevalence of plaque

bacteria, gingivitis and gingival recession in

and around the RPD abutment teeth, especially

in areas within 3mm of the RPDs. 7 However,

in other studies, patients with RPDs have

reported only marginal inflammation.8,9

It has been established that a critical feature

of removable prostheses is the relationship of

acrylic resin denture bases to the gingival

margins of RPD abutment teeth. 10 One study

concluded that gingival areas covered by

RPDs, without relief, show the most adverse

periodontal reactions clinically and

histologically, uncovered the least affected.11

Another study included assessment of

periodontal parameters, plaque index, gingival

index, probing pocket depth, gingival recession

and mobility in relation to teeth in direct

contact with the acrylic base of prosthesis.12

Although there are many studies available in

the literature regarding the detrimental effects

of RPDs on periodontal health and parameters,

6,8,12-14 one included the teeth in the same arch

as the test and controls10. Therefore, the

purpose of this study was to assess the

periodontal parameters, plaque score, bleeding

on probing, probing pocket depth, gingival

recession and loss of attachment of teeth in

4

contact with denture base of RPDs and to

compare them with teeth in the opposite side of

the same arch not in contact with the denture

base. The null hypothesis for this study is that

there will be no significant differences between

teeth in the same arch with contact or no

contact with RPD base, subjected equally to

factors contributing to retention of plaque,

bleeding on probing and loss of attachment.

Side of the maxillary arch in contact with the

denture base was considered as the

experimental variable.

METHODS

The initial group of the study consisted of 46

patients at the Department of Prosthetic

Dentistry, University of Peradeniya, Sri Lanka

during the year of 2009. The sample size,

determined with a power of 80%, was doubled

initially to allow for patients lost to follow-up

at the end of 6 months. The group at the end of

6 months consisted of 10 males and 12 females

between the ages of 21 and 43 years. The mean

age of the study sample was 28.3 years.

Patients were educated and informed about the

difference between both sides of the denture

base and requested to report any experience of

discomfort. Written consent was obtained prior

to clinical procedures.

Parameters were defined for the actual sample

in order to minimize confounding factors that

could otherwise significantly affect the data

and results. Patients were selected for inclusion

in the study if they met the following criteria:

1. Absence of significant medical history, i.e.

neither diagnosed with any medical condition

nor taking any medication on a regular basis;

2. Non-smokers;

3. Fewer than four maxillary teeth missing;

4. Complete mandibular dentitions

Prior to prosthetic treatment, all necessary

dental treatment and restorations were

completed. These included oral hygiene

instructions, full mouth scaling and polishing

and root surface debridement of teeth with

probing pocket depth of 4-7 mm under local

anaesthesia, and surgical root surface

debridement of teeth with probing pocket

depths greater than 7 mm with open flap

procedures under local anaesthesia. Restorative

treatment including correction of overhanging

restorative margins, endodontic treatment and

restorations were also carried out.

The prosthetic treatments associated with

acrylic resin partial dentures were carried out

by the principal investigator to avoid inter-

5

examiner variability. Maxillary partial dentures

were designed in such a way that the gingival

margins of two teeth on one side of the arch

were in contact with the acrylic resin denture

bases (control side). The contra lateral teeth

had no contact with the acrylic resin denture

bases (test side) (6 x 10mm in bucco-lingual

and mesial/distal dimensions. Therefore the

peripheral margins of one side (right/left) of

the denture bases did not contact the gingival

margins of the teeth (e.g.: right side of the

denture base in the premolar region in fig.1).

The denture base on the contra lateral side was

designed to contact the gingival margins of the

teeth (e.g.: left side of the denture base in fig.1

contact with premolars). Assignment of arch to

test/control group was randomized prior to

patient examination.

All patients were educated and advised on

denture maintenance procedures with

demonstrations. They were advised to brush

the dentures and to keep them out of mouth (in

water of room temperature) every night after

cleaning. Dentures were routinely evaluated in

every visit for plaque, stains and deposits and

were cleaned accordingly. The importance of

denture hygiene was reinforced on each visit.

Initial periodontal assessments were

accomplished prior to fabrication of the partial

dentures. All patients were recalled at 2 week,

3 month and 6 month intervals after denture

insertions. Similar readings were obtained at

each visit. Periodontal assessments at each

visit were accomplished by the principal

investigator to avoid inter-examiner variability.

Intra-examiner variability was ascertained by

re-examining 10% of the measurements on a

particular session. During the follow up period,

all patients were given standard maintenance

care with advice on plaque control according

to the criteria for maintenance care adhered to

by the Division of Periodontology, Faculty of

Dental Sciences.

Plaque (PLS) and bleeding scores (BOP)

were calculated by measuring distopalatal,

midpalatal and mesiopalatal aspects of test and

control teeth. The average value was

considered as a percentage of total number of

teeth surfaces. The readings for pocket depths

(PPD) and gingival recession (GR) were

recorded on the palatal aspects of test and

control teeth. Three readings were made for

each tooth i.e., mesio-palatal, mid-palatal and

disto-palatal, the mean pocket depths were

considered to be the score. Probing pocket

depths were measured to the nearest millimetre

from the gingival margin to the base of the

pocket using a periodontal probe (University

6

of Michigan “O” with William marking

diameter tip 0.5mm) placed parallel to the long

axis of the tooth. PPD of each site was

categorized into less than or equal to 3mm

(≤3mm) and more than 3mm (>3mm). A

similar procedure was carried out for gingival

recession (GR), except that the measurements

were recorded from the gingival margins to the

cemento-enamel junctions. The mean values

obtained for PPD and GR of a corresponding

tooth were totalled to obtain the mean value for

attachment loss (LOA) of a given tooth. GR

was considered as less than or equal to 1mm

and more than 1mm (≤1mm and >1mm). LOA

was noted to be less than or equal to 3mm

(≤3mm) and more than 3mm (>3mm).

All study related procedures were approved

by the Ethics Review Committee at the Faculty

of Dental Sciences, University of Peradeniya.

(Approval number:

FDS-RERC/2009/02/MJAYAS 1)

Statistics

Paired t test was used to compare data related

to plaque scores in pre op test and control.

Two-way repeated Measures Analysis of

Variance Test was used for comparison data

related to plaque scores and bleeding scores in

pre op, 2 weeks, 3 months and 6 months in

test/control groups.

Multiple comparisons for plaque scores and

bleeding scores were carried out.

All Pair wise Multiple Comparison

Procedures were used to compare data between

baseline, 2 weeks, 3 months and 6 months

within the same group (e.g.: to compare data

between baseline, 2weeks, 3 months and 6

months in plaque score test group)

Chi-square was used to compare data related

to probing pocket depths, loss of attachment

and gingival recession in test and control sides

of pre treatment. McNemar test was used to

compare PPD, LOA and GR between baseline,

2weeks, 3 months and 6 months on test and

control sides. The level of significance was

p<0.05. The differences between initial values

of the test and control sides (PT-t vs. PT-c)

were compared.

RESULTS

Although 46 patients received the prosthetic

treatment, only 22 patients returned for follow

up 6 months post RPD placement. Thus, 48%

of the patients who received RPD returned for

follow-up. Baseline measures (PT) for the

initial group and follow up group were

compared; no significant difference was noted.

7

The difference between PT values of test and

control sides for all parameters was not

statistically significant.

Table 1 shows the distribution of plaque

scores for the test and control sides at each

visit (pre-prosthetic treatment, 2 weeks, 3

months and 6 months post RPD insertion

respectively). A general trend regarding an

increase in PLS for the control sides was noted

as the duration of RPD wear increased.

The changes associated with PLS for 2 weeks

post RPD placement were not significant. A

statistically significant difference was found on

control side between baseline values and at 3

months and 6 months post RPD insertion.

[53.5% (p>0.05) and 66.64% (p<0.001) at 3

months and 56% (p>0.05) 78.77% (p<0.001) at

6 months respectively].

The frequency of distribution of BOP, test

versus controls, at each visit is shown in Table

2. The difference at 2 weeks’ recall was not

significant. However, data for 3 months and 6

months recall were 29.77% and 32.65% for the

test sides and 40.18% and 44.15% for the

control sides, demonstrated a statistically

significant difference in the latter side.

Table 3 shows the frequency distribution of

PPD in relation to the test and control sides.

The percentages of sites with PPD ≤ 3mm and

≥ 3mm were clearly defined. It was 0%, 0%,

2% and 4% for the PPD >3mm for the test

sides for pre prosthetic treatment, 2weeks, 3

months and 6 months recall visits, whereas

3%, 3%, 21% and 46% for the control sides

respectively during similar visits. Although 2

weeks recall data does not show a significant

difference in PPD more than 3mm between test

and control sides, data for 3 months and 6

months show a highly significant difference in

the control side with p<0.001.

Table 4 contains data in relation to LOA

considering percentage of sites with less than

or equal to 3mm and more than 3mm. They

were 0%, 0%, 2% and 6% of LOA more than

3mm for the test side and 1%, 6%, 24% and

79% for the control side during pre prosthetic

treatment, and at the 2 week, 3 month and 6

month recall visits respectively. The 3 and 6

months recall data show a significant

difference in LOA more than 3 mm in the

control side (p<0.001) whereas no such

significant difference was observed in the test

side.

8

The values for GR are shown in Table 5. The

values in the test side were 25%, 23%, 27%

and 32% for GR => 1mm for the test side and

the relevant values for the control side were

46%, 55%, 66% and 82% respectively. Data

for the 3 month and 6 month recall shows a

significant increase in the percentage of sites

with GR =>1mm in control side.

DISCUSSION

Although there are numerous studies in the

literature 4-9 regarding the relationship between

RPDs and periodontal health, no papers have

been published specifically regarding the Sri

Lankan population. Sri Lanka differs from its

neighbouring South Asian countries due to its

medium-level socioeconomic status,

availability of government based free heath

care and educational facilities. Therefore, such

a study would also facilitate one aspect of the

cost effectiveness of education and oral health

care provided mostly free of charge by the

government.

Out of the sample of 46 patients, only 48%

remained for follow up at the end of 6 months.

Other studies have also experienced similar

difficulties regarding long term follow up of

prosthetic patients.9, 12. The selection criteria

used in this study attempted to reduce

confounding factors associated with systemic

and environmental considerations such as

smoking and the use of other prostheses. Use

of the same patient as test and control

minimized the individual differences.

Categorization of teeth in contact and not in

contact with RPDs is considered to be an

established method to study possible effects of

denture wearing on oral health.15 Various

studies have investigated the factors that might

be related to occurrence of plaque, calculus

accumulation and gingival inflammation,

changes in PPD, tooth mobility and GR on

abutment and non abutment teeth in patients

wearing RPDs.4, 16

Studies by Bergman, Bates & Addy,

McHenry& Johannsen et al, and Brill & Tryde

et al have shown that partial dentures in the

mouth increase plaque formation4, 17, 18, 19

particularly, as shown by Ghamrawy, on tooth

surfaces in contact with the partial dentures.20

The results of this study also confirmed this by

demonstrating significant increases in plaque

score on teeth in contact with denture bases 3

months and 6 months post denture wearing.

Bissada et al (1974) concluded that gingival

areas covered by parts of RPDs without relief

9

demonstrated the most adverse periodontal

reactions both clinically and histologically,

whereas the uncovered areas were the least

affected.11 The most severe gingival changes

were seen in areas where an acrylic resin

denture base covered the gingival margins.

Based on the data in the present study, the

authors propose that a distance of 5 to 6 mm be

maintained from the gingival margins for all

RPD components. Findings from the present

study support those from a 1994 study by

Yusof and Isa, who reported a significant

increase in plaque index, gingival index and

LOA of teeth in contact with acrylic resin

denture base of RPDs when compared with

other teeth in the opposing arch not related to

any prosthesis.12

Bissada, Ibrahim et al, Brill, Tryde et al and

Stipho, Murphy et al have shown that coverage

of marginal gingival tissues with RPDs

enhances gingival inflammation around

abutment teeth.11,19,21 This finding is confirmed

by the present study as it demonstrated an

increase in BOP on the side of RPD in contact

with teeth at 3 and 6 months of denture

wearing.

In a 10 year retrospective study Kern &

Wagner reported an increase in probing depth

and tooth mobility in RPD wearers.22 Yeung et

al in a clinical study with cobalt-chromium

RPDs found that there were significant

(p<0.001) increases in probing depths around

teeth in contact with RPDs.7 Tawse-Smith,

Rivillas et al compared the short term clinical

effects of an experimental acrylic removable

appliance. Their study revealed that the side of

the arch in contact with acrylic resin base

showed significantly higher gingival index

scores and probing depth measurements during

the 21 days of the study when contrasted with

the side of the arch relieved from the acrylic

resin bases.10 After the test prosthesis was

discontinued, the PPD measurements returned

to baseline levels or better on both sides. The

authors concluded that there were potential

irritant effects of various denture base designs

on gingival tissues.

The results of this study are compatible with

the above studies that reported increased

findings regarding PPD, GR and LOA in teeth

in contact with RPDs. Multiple authors have

suggested simpler designs, less tissue coverage

and frequent recalls for all patients. A number

of clinical studies have concluded that proper

plaque control in RPD wearers depend on strict

recall and optimal personal oral hygiene.23, 24, 25

It is suggested that a denture base kept well

10

relieved from the gingival margin with regular

denture and periodontal maintenance will

improve periodontal health in RPD wearers.

CONCLUSION

Removable acrylic resin partial dentures tend

to adversely affect periodontal parameters

when teeth are in contact with resin base. This

effect is increased with longer duration of RPD

wear. Therefore, it is recommended to keep the

dentures well relieved (at least 6x10mm) from

the gingival margin wherever possible.

REFERENCES

1. Wostmann, B., E. Budtz-Jorgensen, et

al. Indications for removable partial

dentures: a literature review. Int J

Prosthodont 2005;18(2): 139-45.

2. Kapur, K. K. Veterans Administration

Cooperative Dental Implant Study--

comparisons between fixed partial

dentures supported by blade-vent

implants and removable partial

dentures. Part III: Comparisons of

masticatory scores between two

treatment modalities. J Prosthet Dent

1991; 65(2): 272-83.

3. Kapur, K. K. Veterans Administration

Cooperative Dental Implant Study--

comparisons between fixed partial

dentures supported by blade-vent

implants and removable partial

dentures. Part IV: Comparisons of

patient satisfaction between two

treatment modalities. J Prosthet Dent

1991; 66(4): 517-30.

4. Bergman, B. Periodontal reactions

related to removable partial dentures:

a literature review. J Prosthet Dent

1987; 58(4): 454-8.

5. Drake, C. W. and J. D. Beck. The oral

status of elderly removable partial

denture wearers. J Oral Rehabil

1993; 20(1): 53-60.

6. Carlsson, G. E., B. Hedegard, et al.

Studies in partial dental prosthesis.

IV. Final results of a 4-year

longitudinal investigation of

dentogingivally supported partial

dentures. Acta Odontol Scand 1965;

23(5): 443-72.

7. Yeung, A. L., E. C. Lo, et al. Oral

health status of patients 5-6 years

after placement of cobalt-chromium

removable partial dentures. J Oral

Rehabil 2000; 27(3): 183-9.

11

8. Schwalm, C. A., D. E. Smith, et al. A

clinical study of patients 1 to 2 years

after placement of removable partial

dentures. J Prosthet Dent 1977; 38(4):

380-91.

9. Gomes, B. C., R. P. Renner, et al.

Periodontal considerations in

removable partial dentures. J Am

Dent Assoc 1980; 101(3): 496-8.

10. Tawse-Smith, A., C. C. Rivillas, et al.

Clinical effects of removable acrylic

appliance design on gingival tissues: a

short-term study. J Int Acad

Periodontol 2001; 3(1): 22-7

11. Bissada, N. F., S. I. Ibrahim, et al.

Gingival response to various types of

removable partial dentures. J

Periodontol 1974; 45(9): 651-9.

12. Yusof, Z. and Z. Isa. Periodontal

status of teeth in contact with denture

in removable partial denture wearers.

J Oral Rehabil 1994; 21(1): 77-86.

13. Miyaura, K., M. Morita, et al.

Rehabilitation of biting abilities in

patients with different types of dental

prostheses. J Oral Rehabil 2000;

27(12): 1073-6.

14. Dolan, T. A. and K. A. Atchison.

Implications of access, utilization and

need for oral health care by the non-

institutionalized and institutionalized

elderly on the dental delivery system.

J Dent Educ 1993; 57(12): 876-87.

15. Chandler, J. A. and Brudvik, J.S.

Clinical evaluation of patients eight to

nine years after placement of

removable partial dentures. J Prosthet

Dent 1984; 51(6): 736-43.

16. Zlataric, D. K., A. Celebic, et al. The

effect of removable partial dentures

on periodontal health of abutment and

non-abutment teeth. J Periodontol

2002; 73(2): 137-44.

17. Bates, J. F. and M. Addy. Partial

dentures and plaque accumulation. J

Dent 1978; 6(4): 285-93.

18. McHenry, K. R., O. E. Johansson, et

al. The effect of removable partial

denture framework design on gingival

inflammation: a clinical model. J

Prosthet Dent 1992; 68(5): 799-803.

19. Brill, N., G. Tryde, et al. Ecologic

changes in the oral cavity caused by

removable partial dentures. J Prosthet

Dent 1977; 38(2): 138-48.

20. Ghamrawy, E. E. Quantitative

changes in dental plaque formation

related to removable partial dentures.

J Oral Rehabil 1976; 3(2): 115-20.

12

21. Stipho, H. D., W. M. Murphy, et al.

Effect of oral prostheses on plaque

accumulation. Br Dent J 1978;

145(2): 47-50.

22. Kern, M. and B. Wagner. Periodontal

findings in patients 10 years after

insertion of removable partial

dentures. J Oral Rehabil 2001; 28(11):

991-7.

23. Bergman, B., A. Hugoson, et al. A 25

year longitudinal study of patients

treated with removable partial

dentures. J Oral Rehabil 1995; 22(8):

595-9.

24. Bassi, F., G. Mantecchini, et al. Oral

conditions and aptitude to receive

implants in patients with removable

partial dentures: a cross-sectional

study. part I. oral conditions. J Oral

Rehabil 1996; 23(1): 50-4.

25. Mojon, P., A. Rentsch, et al.

Relationship between prosthodontic

status, caries, and periodontal disease

in a geriatric population. Int J

Prosthodont 1995; 8(6): 564-71.

13

Table 1-The frequency distribution of PLS in test and control sides of denture-percentage of sites with comparison between each recall appointment –significance is tested to baseline or within

baseline

PT (Baseline) 2 Weeks 3Months 6 Months

Test (t) side 53.77% 48.50% 53.05% 56%

*Group p

value(test

side)

P>0.05 P>0.05 P>0.05

Control (c) side 51.50% 54.50% 66.64% 78.77%

*Group p

value(contro

l side)

P>0.05 P<0.001 P<0.001

#Initial p

value

P>0.05

PT=Pre treatment

*comparing the differences in percentages between baseline and relevant follow up appointment

#comparing the difference between test and control sides at baseline

14

Table 2-The frequency distribution of BOP in test and control sides of denture- percentage of sites with comparison between each recall appointment

PT (Base line) 2 Weeks 3 Months 6 Months

Test (t) side 24.27% 26.50% 29.77% 32.65%

*Group p

value(test side)

P>0.05 P>0.05 P>0.05

Control(c)side 23.27% 30.91% 40.18% 44.15%

*Group p

value(control

side)

P>0.05 P<0.001 P<0.001

#Initial p value P>0.05

PT=Pre treatment

*comparing the differences in percentages between baseline and relevant follow up appointment

#comparing the difference between test and control sides at baseline

15

Table 3-The frequency distribution of PPD in test and control sides –percentage of sites with comparison between each recall appointment

PT (Base line) 2 Weeks 3 Months 6 Months

Test (t) side <=3mm

100%

>3mm

0

<=3mm

100%

>3mm

0

<=3mm

98%

>3mm

2%

<=3mm

96%

>3mm

4%

*Group p

value(test side)

p>0.05 P>0.05 P>0.05

Control (c) side <=3mm

97%

>3mm

3%

<=3mm

97%

>3mm

3%

<=3mm

79%

>3mm

21%

<=3mm

54%

>3mm

46%

*Group p

value(control

side)

P>0.05 P<0.05 P<0.001

#Initial p

value

P>0.05

PT=Pre treatment

*comparing the differences in PPD between baseline and relevant follow up appointment

#comparing the difference between test and control sides at baseline

16

Table 4-The frequency of distribution of LOA in test and control sides –percentage of sites with comparison between each recall appointment

PT (Base line) 2 Weeks 3 Months 6 Months

Test (t) side <=3mm

100%

>3mm

0

<=3mm

100%

>3mm

0

<=3mm

98%

>3mm

2%

<=3mm

94%

>3mm

6%

*Group p

value(test

side)

p>0.05 p>0.05 p>0.05

Control (c)

side

<=3mm

99%

>3mm

1%

<=3mm

94%

>3mm

6%

<=3mm

76%

>3mm

24%

<=3mm

21%

>3mm

79%

*Group p

value(contro

l side)

p>0.05 P<0.001 P<0.001

#Initial p

value

P>0.05

PT=Pre treatment *comparing the differences in LOA between baseline and relevant follow up appointment

#comparing the difference between test and control sides at baseline

17

Table 5- The frequency of distribution of GR in test and control sides –percentage of sites with comparison between each recall appointment

PT (Base line) 2 Weeks 3 Months 6 Months

Test (t) side 0 mm

75%

=>1mm

25%

0 mm

77%

=>1mm

23%

0 mm

73%

=>1mm

27%

0 mm

68%

=>1mm

32%

*Group p

value(test

side)

p>0.05 p>0.05 p>0.05

Control (c) side 0 mm

54%

=>1mm

46%

0 mm

45%

=>1mm

55%

0 mm

34%

=>1mm

66%

0 mm

18%

=>1mm

82%

*Group p

value(control

side)

p>0.05 P<0.05 P<0.001

#Initial p value P>0.05

PT=Pre treatment *comparing the differences in GR between baseline and relevant follow up appointment

#comparing the difference between test and control sides at baseline

18