Effect of Postoperative Bleaching on Clinical Performance

of Three Contemporary Composite Resins Restoration

Dr. Ameer Hamdi ALAmeedeeAssist. Prof. Dr. Operative and Esthetic Dentistry

Lect. Dr. Ghada Ali Abdol- HussianBSc, MsC, Pharmacology.

Vital tooth bleaching is considered the most conservative treatment for discolored teeth and has been shown to be efficient when used with careful case selection, diagnosis and treatment planning. However, some clinicians express concern about the effect of these agents on dental restorative materials present in the esthetic zone,

previous studies that indicated potential changes in the physical properties of composite resin restorations after bleaching, could not demonstrate the clinical relevance of these changes and recommended further clinical research. Thus, it was found to be necessary to in vivo evaluate the effect of in-office bleaching on three types of restorative material

Materials

Beautifil II, nano-hybrid composite (Giomer)

Materials used for the in vivo study

Ceram.x.mono, nano ceramic micro-hybrid composite resin (Ormocer)

IPS Empress Direct, nano-hybrid composite resin (Ceromer)

In-office Zoom bleaching material kit

The objective of this study was to evaluate the effect of in-office bleaching on the clinical performance of three contemporary hybrid composite resins.

Methodology

The measurement performed before bleaching , two days, three months, six months and one year after bleaching(T0,T1,T2,T3, and T4) follow up time periods.

Schematic drawing of the in vivo study pathway

30 restorations (12 patients)

Modified Ryge CriteriaThe (A) and (B) scores were considered clinically acceptable.

The (C) and (D) scores were considered clinically unacceptable

In this study, from 15 subject only 12 subject (tooth shade A3), 18-38 years old with CL IV (30 toothwith CL IV restorations). Divided 3 groups according to type of restorative materials. Each group (n=10tooth with Cl IV restorations shade A1) subdivided to 4 groups according to four follow up timeperiods.

Inclusion criteria Exclusion criteria

1-Motivated 18-years or older 2-Good oral health 3-Having one or more vital anterior defective class IV that require restoration or class III with labial extension4-Having baseline shade A35-Teeth are free of visible cracks, no signs of preoperative sensitivity

1-Systemic diseases or taking medication that cause discoloration2-Severe bruxism, tooth clenching, or unstable occlusion 3-History of hydrogen-peroxide product sensitivity 4-Users of bleaching products in the past three years. 5-Cavities with sub-gingival wall extensions

Table 1 , Inclusion and exclusion criteria

Table Clinical evaluation according to Clinical criteria according to Modified Ryge criteria of the restorationRyge Criteria scoreTest procedureClinical Criteria

A: No loss of restorative materialVisual inspection with

explorer and mirror if neededRetention

C: loss of restorative material

A: the restoration matches the adjacent tooth structure in color and

translucencyVisual inspection with

mirror at 18 inchesColor match

B: light mismatch in color and translucency between the restoration

and the adjacent tooth structure

C: mismatch in color and translucency is outside the acceptable

range of tooth color and translucency

A: no discoloration anywhere along the margin between the

restoration and adjacent toothVisual inspection with

mirror at 18 inchesMarginal

discoloration B: slight discoloration along the margin between the restoration and

adjacent tooth can be polished away

C: discoloration penetrated along the margin between the restoration

material in a pulpal direction can’t be polished away

A: no evidence of cariesVisual inspection with

explorer and mirror if neededSecondary

caries

B: secondary caries at restoration

margin

A: the restoration is continuous with existing anatomical formVisual inspection with

explorer and mirror if neededAnatomical

form

B: the restoration is discontinuous with existing anatomical form.

But the material is not sufficient to expose the dentine or base

C: sufficient material lost to expose the dentine or base

A: no visual evidence of a crevice along the marginVisual inspection with

explorer and mirror if neededMarginal

Integrity

B: visual evidence of a crevice along the margin into which the

explorer will penetrate

C: the dentin or base exposed

D: restoration is fractured, mobile, or missing

A: the restoration surface is as smooth as surrounding enamelVisual inspection with

explorer and mirror if neededSurface texture

B: the restoration surface is slightly rough or pitted than

surrounding enamel

C: the restoration surface is rougher than surrounding enamel

D: the restoration surface is deeply pitted, irregular grooves than

surrounding enamel

Data were collected and analyzed using SPSS version 20 software. Chi-square (X2) was used for the qualitative data test to investigate the criteria. A least significant differences (LSD) test for repeated measures and an analysis of variance was performed to compare the three restoration types.

Results:

From total of 15 subjects (36-restorations), three subjects were dropped out as they skipped attwo-days recall visit. 12 subjects having a total of 30-restorations were available at all recall visits.

Groups T0 T1 T2 T3 T4

Bea 12 10 10 10 10

IPS 12 10 10 10 10

Cer 12 10 10 10 10

Bea: Beautifil II group, IPS: IPS Empress Direct group, Cer: Ceram.x.mono group

T0: Before bleaching, T1: Two-days after bleaching, T2: Three-months after bleaching,

T3: Six-months after bleaching, T4: One-year after bleaching

Number of restorations evaluated at each recall examination

When teeth are bleached, the internal stains are oxidized and teeth appear more bright with increased opacity. Therefore, the color obtained from translucent enamel and opaque dentin shade could not simulate the final bleached shade of the teeth in 60% of the restoration after bleaching, yet it was clinically acceptable and rated as B.At one-year period, 10% of IPS-Empress Direct group, showed colormismatch which was clinically unacceptable (C rating)and required replacement. This mismatch could be attributed to the translucent enamel shade which decreased the value and to color relapse of the teeth.

Previous studies reported significant influence of bleaching on the physical properties of composite resin as well as dissolution and leaking of ions such as Barium, Silicon, and Strontium could be referred to the larger the filler particles (Arikawa et al, 2007; Ameri et al, 2010).

Also, the high oxidation and degradation of the resinous matrix in the composite resins and the higher susceptibility to water sorption may cause potential change conditions (Mourouzis et al, 2013).

In contrast, the results of our study did not show any significant difference among the three materials with respect to surface texture and anatomical form over one-year period. Composite resins used in this study are nano-hybrids with more amount of nanofillers and less amount of micro-fillers. This could explain the stability of these materials under bleaching

In accordance to our results, Ayad et al (2009),who conducted a study using an Ormocer (Admira) subjected to different types of bleaching agents for different durations and concluded that this material showed resistance to bleaching.Furthermore, Bryant et al 2015, indicated that the size and morphology of filler particles influence the mechanical and physical properties while nanoparticles and clusters in the nanofilled materials improved it.

The clinical durability of composite restorations depends on successful bonding of the composite resin to the tooth surface.

Change in marginal integrity may indicate change in the chemical behaviorof the material as a result of bleaching and/or aging.

The present study did not show any significant change among the three restoratives with respect to retention, marginal integrity and secondary caries.

This may highlight that in-office bleaching has no harmful effect on bonding or the bonded interface.

However, only 10% of IPS group showed marginal discoloration at 6-months and one-year period. Cavity preparation and the bonding procedures were standardized for all specimens using the same bonding material and technique, which exclude the possibility of bond failure due to bleaching. Therefore, one reasonable explanation could be related to individual patient oral environmental factors as salivary pH or mastication habits.

Clinical Evaluation of the Restorative Materials:

1- The survival rate (retention) at one-year was 100% for all restorations. Moreover, therewas no statistically significant difference as regard to retention, recurrent caries, anatomicform, surface texture, marginal integrity and marginal discoloration at all time periods.

2- There was a statistically significant difference among the three composite resinrestoration types in color match at all time periods after bleaching.

3- Regarding to marginal discoloration, it was found that at one-year recall, 10% of IPS-

Empress Direct group restorations were considered clinically unacceptable and requiredreplacement. However, all restorations were considered clinically acceptable.

4- Our study did not show any statistically significant difference among the three materialswith respect to surface texture and anatomical form over one-year period.

5- The clinical durability of composite restorations depends on successful bonding of the composite resin to the tooth surface.

6- The present study did not show any significant change among the three restoratives with respect to retention, marginal integrity and secondary caries.

In contrast, the results of our study did not show any significant difference among the three materials with respect to surface texture and anatomical form over one-year period.

Composite resins used in this study are nano-hybrids with more amount of nanofillersand less amount of micro-fillers. This could explain the stability of these materials under bleaching

Conclusion

Within the limitations of this in vivo study, the following conclusions were assumed:

1-The difference in the composition of the composite resins used contributed to thedifference in their reaction to bleaching as well as to aging.

2-Color of Ceram.x.mono (Ormocer) and IPS Empress Direct (Ceromer) compositeresin restorations were found to be more stable under bleaching conditions thanBeautiful II (Giomer) clinically.

3-The color of Fluoride releasing restorative materials appeared to be more alteredby bleaching.

4-Color alteration as a result of bleaching was found to be clinically unnoticeable.

5-The selection of a lighter composite resin shade prior to bleaching may berecommended.

Conclusion

6- The marginal discrepancy at the tooth restoration interface is considered clinically acceptable and the effect bleaching may be considered minor and clinically not significant.

7- The one-year clinical evaluation of all tested restorations considered clinically acceptable.

8- Ceram.x.mono nano-hybrid composite (an ormocer) showed better clinical performance at one-year recall compared to the other two restorations.

9-Under the clinical situation, composite resin restorative materials used required no replacement after bleaching. Surface refurbishment may be recommended for certain types of composite resin restorations.