The repair of direct composite restorations: an international survey of the teaching of operative techniques and materials

Repair versus replacement of defective direct dental restorations: A multinational cross-sectional study with meta-analysis

OBJECTIVES

When dental practitioners encounter a defective restoration, they are faced with a crucial decision whether to repair or replace it. This study aims to explore international preferences for repair procedures and the clinical steps taken during the repair process.

METHOD

An 11-question survey was distributed to dentists across 21 countries via different platforms. The survey comprised two sections: the first included five questions aimed at gathering demographic information, while the second consisted of six questions focusing on participants' practices related to the repair of composite or amalgam restorations A meta-analysis was employed to ascertain the pooled odds ratio of repairing versus replacement. The statistical analysis was carried out using the RevMan 5.3 program and forest plots were generated using the same program to visualize the results.

RESULTS

The survey was completed by 3680 dental practitioners. The results indicated a strong tendency to repair defective composite restorations (OR: 14.23; 95 % CI: 7.40, 27.35, p < 0.001). In terms of amalgam, there was a significant tendency to replace the restorations (OR: 0.19; 95 % CI: 0.12, 0.30, p < 0.001). When repairing restorations, the most common protocols were etching with orthophosphoric acid and creating an enamel bevel, regardless of the restorative material used.

CONCLUSION

The findings of this study indicate that there exists a knowledge gap among dental practitioners regarding restoration repair. It is imperative that dental practitioners receive proper education and training on restoration repair, to ensure the usage of adequate protocols and restoration survival.

CLINICAL SIGNIFICANCE

A significant portion of dental practitioners lack the necessary knowledge and education required for the repair of restorations. Therefore, it is imperative to establish guidelines aimed at enhancing the management of defective restorations, along with protocols for clinical interventions. This includes the incorporation of proper courses in undergraduate, graduate, and continuing education programs.

Teaching of composite restoration repair in Brazilian dental schools

OBJECTIVES

The aim was to investigate aspects of the teaching of restoration repair as a minimally invasive alternative to replacing defective direct composite restorations in undergraduate curricula teaching programs in Brazilian dental schools.

METHODS

A 14-item validated survey questionnaire was mailed to directors/coordinators of operative/restorative dentistry teachers of Brazilian Dental Schools. Data were collected on demographic characteristics of the teachers and institutions, together with questions on the teaching of the repair of defective resin-based composite restorations as part of the school curriculum; the rationale behind the teaching; the nature of the teaching (preclinical and/or clinical); how techniques were taught, indications for repair, operative techniques, materials used, patient acceptability and expected longevity of completed repairs.

RESULTS

Two hundred and twenty-two (94%) directors/ coordinators of dental curricula in Brazil were contacted. One hundred and thirty-one directors/coordinators (59%) replied, providing the e-mail address from the teacher responsible for the operative/restorative dentistry program in their school. Of these, 104 responded to the questionnaire (79% response rate). Ninety-three (89%) of the participating schools reported teaching composite repairs as an alternative to replacing restorations. Of the theoretical content, 43% was taught at preclinical and clinical levels, whereas most practical experience (53%) was acquired at clinical levels. Eighty-eight schools (95%) reported tooth substance preservation being the main reason for teaching repair techniques. All schools that taught repairs reported high patient acceptability.

CONCLUSIONS

The teaching of composite restoration repair as an alternative to restoration replacement is established in undergraduate programs in most of the Brazilian dental schools surveyed.

CLINICAL SIGNIFICANCE

The reasons for teaching restoration repair in Brazil were found to be quite unanimous among teachers, especially regarding the preservation of tooth structure. Variations were found in the clinical indications for repair, suggesting the need for further investigations. Monitoring repaired restorations should be encouraged and could contribute to future studies.

Effect of Argon Plasma Surface Treatment on Repair of Resin Composite Aged Two Years

OBJECTIVES

To evaluate the effect of argon plasma treatment (PLA) when combined with sandblasting (SAN), silanization (SIL), and hydrophobic bonding resin (HBR) on the shear bond strength (SBS) of a two-year water-aged resin composite bonded to a newly placed composite after 24 hours and one year of water-storage.

METHODS AND MATERIALS

Thirty-six light-cured composite plates (20mm x 20mm x 4mm thick) were obtained and stored at 37°C in distilled water for 2 years. These aged plates were distributed into 6 groups (n=6) according to the surface treatment: no treatment (Negative Control); SAN+SIL+HBR (Positive Control); SAN+PLA+SIL+HBR; PLA+ SIL+HBR; PLA+SIL; PLA+HBR. Fresh resin composite cylinders were built up using silicone molds (hole: 1.5 mm high x 1.5 mm diameter) positioned over the aged plates. Half of the SBS samples were stored in distilled water for 24 hours and loaded until failure, while the other half were stored for 1 year before being tested. Data were submitted to two-way analysis of variance and post-hoc Tukey Test (preset alpha of 0.05).

RESULTS

Positive Control, SAN+PLA+SIL+HBR and PLA+SIL+HBR groups presented higher SBS means at the 24 hour evaluation. After 1 year of water storage, all groups demonstrated significant SBS reduction, with the SAN+PLA+SIL+HBR group presenting the highest SBS.

CONCLUSIONS

Resin plasma treatment in combination with other surface treatments can improve the SBS of composite repairs after one year of water storage. The SBS of the composite repair was not stable over time regardless of the surface treatment.

Teaching of the repair of defective composite restorations in Middle Eastern and North African Dental Schools

OBJECTIVES

To evaluate the status of teaching of repair of defective resin-based composite restorations in dental schools in the Middle Eastern and North African (MENA) countries.

METHODS

A validated 14-item questionnaire was mailed to the directors of the operative/restorative dentistry department in 40 MENA dental schools. Data were collected on teaching, including whether the repair of resin-based composite restorations was part of the dental school curriculum; the rationale behind the teaching; how techniques were taught, indications for repair, operative techniques, materials used, patient acceptability and expected longevity of the repair procedure.

RESULTS

Thirty-two schools responded to the survey (response rate of 80%). Twenty-two (69%) schools reported the teaching of resin-based composite repairs as an alternative to the replacement of restorations. Of the schools not teaching repairs, 80% indicated that they plan to include this topic in the curriculum within the next five years. Most schools taught theoretical and practical aspects of repair at a clinical level only. Two-thirds of schools reported tooth substance preservation being the main reason for teaching repair techniques. The main indications for repair treatment were marginal defects (59%), followed by partial loss of restoration (56%). Most schools that performed repairs reported high patient acceptability. Considerable variation was noted in relation to expected longevity of resin- based composite repairs.

CONCLUSIONS

The repair of defective resin-based composite restorations is actively taught within most of the surveyed schools. Advantages of repair, compared to replacement include minimum intervention, preservation of tooth structure, and savings of time and cost.

CLINICAL SIGNIFICANCE

The decision between replacing or repairing a defective resin-based composite restoration in the MENA region tends to be based on clinicians' subjective experience and judgement. However, to further enhance the teaching of resin-based composite repair standardised guidelines need to be developed based on existing evidence.

Repair potential of a bulk-fill resin composite: Effect of different surface-treatment protocols

This study evaluated the effect of different surface-treatment protocols on the repair bond strength of a bulk-fill resin composite. One-hundred and forty specimens (Filtek Bulk-fill) were created (5 mm diameter, 4 mm depth) and allocated to one of 14 groups according to surface treatment (no treatment, tribochemical silica coating, sandblasting with aluminum oxide), adhesive application (no adhesive, total-etch, self-etch), and type of repair resin (bulk-fill, universal resin) (n = 10 per group). Twenty specimens were selected for measuring the cohesive strengths of non-aged resin composites and used as reference. Other specimens were thermocycled. Shear bond-strength testing was performed. Data were analyzed using linear regression of bond strength as a function of the surface treatment, type of adhesive and whether or not adhesive was applied, and type of repair resin. The failure modes were analyzed using logistic regression of failure mode (cohesive failure vs. other types, or adhesive failure vs. other types) on the type of surface treatment, adhesive application, and repair resin used. Surface treatment, regardless of whether this was tribochemical silica coating (mean difference = 5.44 MPa; 95% CI = 4.77-6.11) or sandblasting with aluminum oxide (mean difference = 4.22 MPa; 95% CI = 3.55-4.88), resulted in higher shear bond strength than no treatment. Application of adhesive resulted in a substantial and statistically significant decrease of shear bond strength (by 8.77 MPa, for self-etch and by 7.26 MPa for total-etch) relative to no adhesive. Conversely, the type of repair resin did not influence the shear bond strength to any appreciable extent.

Effect of argon plasma on repair bond strength using nanofilled and microhybrid composites

OBJECTIVES

To evaluate the effect of atmospheric pressure plasma (PLA), sandblasting (SAN), silanization (SIL) and hydrophobic bonding resin (HBR) on the micro-shear bond strength (MSBS) of fresh nanofilled (NF) or microhybrid (MH) composites to water-aged nanofilled composite.

MATERIALS AND METHODS

NF plates were fabricated and stored in distilled water for 4 months. The aged plates were assigned to the groups (n = 6): 1- untreated; 2- SAN + SIL + HBR; 3- HBR; 4- PLA + HBR; 5- SAN + HBR; 6- SAN + PLA + HBR; and 7- PLA. Two fresh composite cylinders were constructed on each plate with NF or MH composites and tested after 24 h or 1 year of water-storage, using the MSBS testing. Data were analyzed by three-way ANOVA and Tukey test (α = 0.05).

RESULTS

NF yielded better outcomes than MH at 24 h, which was not observed at 1 year. HBR showed the highest MSBS results, while untreated and PLA groups yielded the lowest one. MSBS reduced for all groups after 1 year.

CONCLUSIONS

Only HBR can obtain good MSBS results, while PLA alone was not beneficial. After 1 year, a reduction in repair MSBS was observed and the type of composite did not influence the results.

CLINICAL RELEVANCE

The repair technique can be simplified with the use of only an adhesive and macromechanical retentions in the old composite, regardless the type of fresh composite.

A randomised controlled study on the effects of different surface treatments and adhesive self-etch functional monomers on the immediate repair bond strength and integrity of the repaired resin composite interface

OBJECTIVES

To evaluate the effects of different surface conditioning methods on the immediate repair bond strength and integrity of the repaired composite interface.

METHODS

One hundred and five resin composite blocks made of a nanohybrid resin composite were randomly assigned to one of the following surface conditioning groups (n = 15/group): Group 1: Gluma Self Etch™ adhesive system, Group 2: Tokuyama Bond Force II™ adhesive system, Group 3: non-roughened and non-conditioned surfaces, Group 4: sandblasting and Gluma Self Etch™, Group 5: sandblasting and Tokuyama Bond Force II™, Group 6: sandblasting only. A positive control group was also used. Resin composite identical to the substrate was applied and the repaired specimens were subjected to shear bond strength (SBS) testing. Representative samples from all groups were subjected to scanning electron microscopy and surface profilometry to determine their mode of failure. The data were analysed statistically using Analysis of Variance (ANOVA) and two independent sample t-test (α = 0.05).

RESULTS

The mean SBS of all test groups ranged between 1.92 and 5.40 MPa and varied with the degree of composite surface roughness and the type of adhesive system employed. Significantly highest SBS values (5.40 ± 0.36 MPa) were obtained in Group 5 (p = 0.017) which were comparable to the coherent strength of the resin composite in the positive control group (p > 0.05).

CONCLUSIONS

Under the tested conditions, significantly greater SBS of repaired resin composite was achieved when the substrate surface was conditioned by sandblasting followed by the application of the Tokuyama Bond Force II™ adhesive system.

CLINICAL SIGNIFICANCE

Effecting a repair of a nanohybrid composite restoration with sandblasting and the application of TBF II would seem to enhance the interfacial bond strength and integrity of the repaired resin composite interface. Clinical trials are necessary to determine the usefulness of this technique.

Restoration Repair as a Contemporary Approach to Tooth Preservation: Criteria for Decision Making and Clinical Recommendations

Despite the growing body of evidence-based knowledge, evidence-based restoration repair is not always applied in the clinical setting. This article is intended to give an evidence-based insight into the indications, importance, benefits and long-term success of resin composite restoration repair, together with details of relevant operative techniques aimed at conserving as much sound tooth structure as possible.

Reparative Dentistry: Possibilities and Limitations

Purpose of Review

Defective dental restorations are amongst the most common encounters in general dental practice. Replacement of defective restorations is often costly and commonly results in the sacrifice of sound tooth structure, thereby compromising the vitality of the dental pulp, potentially resulting in the acceleration of the restoration cycle and premature loss of the restored tooth. With advances in adhesive dentistry, ‘reparative dentistry’ is becoming an important area of minimally invasive dentistry. This article highlights the detrimental biological effects of restoration replacement and provides an overview of current knowledge and understanding of restoration repair as a safe and effective alternative approach to replacement.

Recent Findings

The literature reviewed showed that a growing body of evidence from clinical studies indicates that repaired restorations have similar survival outcomes in patients with low and medium caries risk compared to replaced restorations and are clinically acceptable over a 12-year follow-up of clinical service. Teeth with repaired restorations are less likely to require aggressive interventions such as endodontic treatment or extraction compared to those with replaced restorations.

Summary

Repair options should be carried out wherever possible as minimally interventional procedures in order to increase the longevity of the remaining part of the restoration and the restored tooth unit. Restoration replacement should be considered as the last resort when there are no other viable alternatives.

Understanding the management and teaching of dental restoration repair: Systematic review and meta-analysis of surveys

OBJECTIVES

Repair instead of complete replacement is recommended to manage partially defective restorations. It is unclear if and why such treatment is taught at dental schools or practiced by dentists. We aimed to identify barriers and facilitators for repairs using a systematic review and meta- and qualitative analysis.

SOURCES

Electronic databases (PubMed, CENTRAL, Embase, PsycINFO) were searched.

STUDY SELECTION

Quantitative studies reporting on the proportion of (1) dentists stating to perform repairs, (2) dental schools teaching repairs, (3) failed restorations having been repaired were included. We also included qualitative studies on barriers/facilitators for repairs. Random-effects meta-analyses, meta-regression and a thematic analysis using the theoretical domains framework were conducted.

DATA

401 articles were assessed and 29, mainly quantitative, studies included. 7228 dentists and 276 dental schools had been surveyed, and treatment data of 30,172 restorations evaluated. The mean (95% CI) proportion of dentists stating to perform repairs was 71.5% (49.7-86.4%). 83.3% (73.6-90.0%) of dental schools taught repairs. 31.3% (26.3-36.7%) of failed restorations had been repaired. More recent studies reported significantly more dentists to repair restorations (p=0.004). Employment in public health practices and being the dentist who placed the original restoration were facilitators for repairs. Amalgam restorations were repaired less often, and financial aspects and regulations came as barriers.

CONCLUSIONS

While most dentists state to perform repairs and the vast majority of dental schools teach repairs, the proportion of truly repaired restorations was low. A number of interventions to implement repair in dental practice can be deduced from our findings.

CLINICAL SIGNIFICANCE

Partially defective restorations are common in dental practice. While repairs are taught and dentists are aware of the recommendation towards repairs, the actually performed proportion of repairs seems low.

Attitudes of Greek dentists towards repair of conservative restorations. An online survey

OBJECTIVES

Repair versus replacement of a defective direct restoration is one important step for conserving tooth structure. This study was designed to collect information on the attitudes of Greek dentists towards repairing direct restorations.

METHODS

An electronic questionnaire with 16 multiple-choice and rank-ordering questions was created online and its URL address was randomly emailed to 800 dentists in the area of Athens, Greece. The questionnaire remained open for 3 months, and after two reminder emails the data collected were analysed statistically to identify differences between clinician's sex or years of practicing dentistry, using the chi-square and Kruskal-Wallis tests at α = 0.05.

RESULTS

Three-hundred and twenty dentists completed and submitted the questionnaire (response rate = 40%). A high proportion (86.8%) of the respondents reported that they routinely repair defective restorations, ranking the order of their frequency as 2.47 for amalgam and 2.41 for resin restorations. The reasons, with the highest ranks, for repairing amalgams were the restoration of bulk fractures (4.10) and restoration of marginal fractures (3.69). For repair of resin restorations, the reasons with the highest ranks were improving their colour (4.04) and removing marginal discoloration (3.99). Moreover, 94.1% of the respondents stated that they were enough, much and very much satisfied with the repair, 1 year after it was performed.

CONCLUSIONS

A high percentage of Greek dentists are repairing defective direct restorations. There are discrepancies in the indications, techniques and materials used for repairs, such as bulk fractures and marginal restorations. Further studies on the efficacy of repairs, the criteria and procedure protocols are needed. Further, additional clinical education should be offered at the undergraduate or continuing education levels.

Shear bond strength of different surface treatments in bulk fill, microhybrid, and nanoparticle repair resins

Objectives

The purpose of this study was to evaluate the influence of surface treatment and different types of composite resin on the microshear bond strength of repairs.

Materials and methods

Seventy-two specimens (n=72) were prepared using a nanoparticle resin and stored in artificial saliva at 37 ± 1°C for 24 h. After this period, the specimens (n=24) were restored with microhybrid resin P60 (3M ESPE), nanoparticle resin Filtek Z350 (3M ESPE), and Bulk Fill Surefil SDR Flow (Dentsply) composite resins. Previously, the surfaces of the samples were treated, forming the following subgroups (n=12): (A) conditioned with 37% phosphoric acid for 30 s, and (B) abrasioned with a diamond tip for 3 s and conditioned with 37% phosphoric acid. In all groups, before insertion of the composite resin, the adhesive system Adper Single Bond 2 was actively applied and photopolymerized for 20 s.

Results

The microshear test was executed to assess bond strength. Kruskal–Wallis (p<0.05) and Mann–Whitney statistical tests showed significant statistical difference considering that the bulk-fill resin turned out to have a lower bond strength than the conventional nanoparticle and microhybrid composites. With regard to the technique, the roughening with diamond bur followed by the application of phosphoric acid exhibited values higher than the exclusive use of acid.

Conclusion

The microshear bond strength of the composite resin repairs varies in accordance with the type of composite resin utilized, and roughening the surface increased the bond strength of these materials.

Repair Strength in Simulated Restorations of Methacrylate- or Silorane-Based Composite Resins

The study verified the bond strength in simulated dental restorations of silorane- or methacrylate-based composites repaired with methacrylate-based composite. Methacrylate- (P60) or silorane-based (P90) composites were used associated with adhesive (Adper Single Bond 2). Twenty-four hemi-hourglass-shaped samples were repaired with each composite (n=12). Samples were divided according to groups: G1= P60 + Adper Single Bond 2+ P60; G2= P60 + Adper Single Bond 2 + P60 + thermocycling; G3= P90 + Adper Single Bond 2 + P60; and G4= P90 + Adper Single Bond 2 + P60 + thermocycling. G1 and G3 were submitted to tensile test 24 h after repair procedure, and G2 and G4 after submitted to 5,000 thermocycles at 5 and 55 ?#61616;C for 30 s in each bath. Tensile bond strength test was accomplished in an universal testing machine at crosshead speed of 0.5 mm/min. Data (MPa) were analyzed by two-way ANOVA and Tukey's test (5%). Sample failure pattern (adhesive, cohesive in resin or mixed) was evaluated by stereomicroscope at 30?#61655; and images were obtained in SEM. Bond strength values of methacrylate-based composite samples repaired with methacrylate-based composite (G1 and G2) were greater than for silorane-based samples (G3 and G4). Thermocycling decreased the bond strength values for both composites. All groups showed predominance of adhesive failures and no cohesive failure in composite resin was observed. In conclusion, higher bond strength values were observed in methacrylate-based resin samples and greater percentage of adhesive failures in silorane-based resin samples, both composites repaired with methacrylate-based resin.

Effect of curing and silanizing on composite repair bond strength using an improved micro-tensile test method

Objectives: To evaluate the micro-tensile repair bond strength between aged and new composite, using silane and adhesives that were cured or left uncured when new composite was placed.

Methods: Eighty Filtek Supreme XLT composite blocks and four control blocks were stored in water for two weeks and thermo-cycled. Sandpaper ground, etched and rinsed specimens were divided into two experimental groups: A, no further treatment and B, the surface was coated with bis-silane. Each group was divided into subgroups: (1) Adper Scotchbond Multi-Purpose, (2) Adper Scotchbond Multi-Purpose adhesive, (3) Adper Scotchbond Universal, (4) Clearfil SE Bond and (5) One Step Plus. For each adhesive group, the adhesive was (a) cured according to manufacturer’s instructions or (b) not cured before repair. The substrate blocks were repaired with Filtek Supreme XLT. After aging, they were serially sectioned, producing 1.1 × 1.1 mm square test rods. The rods were prepared for tensile testing and tensile strength calculated at fracture. Type of fracture was examined under microscope.

Results: Leaving the adhesive uncured prior to composite repair placement increased the mean tensile values statistically significant for all adhesives tested, with or without silane pretreatment. Silane surface treatment improved significantly (p < 0.001) tensile strength values for all adhesives, both for the cured and uncured groups. The mean strength of the control composite was higher than the strongest repair strength (p < 0.001).

Conclusions: Application of freshly made silane and a thin bonding layer, rendered higher tensile bond strength. Not curing the adhesive before composite placement increased the tensile bond strength.

Factors influencing repair of dental restorations with resin composite

The presentation of patients with dental restorations that exhibit minor defects is one of the commonest clinical situations in the practice of general dentistry. The repair of such restorations, rather than replacement, is increasingly considered to be a viable alternative to replacement of the defective restoration. This paper considers factors influencing the repair of direct restorations, including indications and details of relevant techniques, based on the best available knowledge and understanding of this important aspect of minimal intervention dentistry. Practitioners who do not consider repair before deciding to replace restorations that present with limited defects are encouraged to consider including repair in the treatment options in such situations. The effective repair of direct restorations can greatly influence the rate of descent down the “restorative death spiral”.

Effect of Mechanical Surface Treatment on the Repair Bond Strength of the Silorane-based Composite Resin

Background and aims. A proper bond must be created between the existing composite resin and the new one for successful repair. The aim of this study was to compare the effect of three mechanical surface treatments, using diamond bur, air abrasion, and Er,Cr:YSGG laser, on the repair bond strength of the silorane-based composite resin. Materials and methods. Sixty cylindrical composite resin specimens (Filtek Silorane) were fabricated and randomly divided into four groups according to surface treatment: group 1 (control group) without any mechanical surface treatment, groups 24 were treated with air abrasion, Er,Cr:YSGG laser, and diamond bur, respectively. In addition, a positive control group was assigned in order to measure the cohesive strength. Silorane bonding agent was used in groups 14 before adding the new composite resin. Then, the specimens were subjected to a shear bond strength test and data was analyzed using one-way ANOVA and post hoc Tukey tests at a significance level of P &0.05. The topographical effects of surface treatments were characterized under a scanning electron microscope. Results. There were statistically significant differences in the repair bond strength values between groups 1 and 2 and groups 3 and 4 (P &0.001). There were no significant differences between groups 1 and 2 (P = 0.98) and groups 3 and 4 (P= 0.97). Conclusion. Surface treatment using Er,Cr:YSGG laser and diamond bur were effective in silorane-based composite resin repair.

Durability of composite repair using different surface treatments

OBJECTIVE

To evaluate the surface treatment and hydrophilicity of the bonding agent on the composite repair strength (RS), silver nitrate uptake (SNU), surface roughness (SR) and estimation of surface area (SA).

METHODS

Fifty resin blocks (Opallis, FGM) were polished and divided in 5 groups: no treatment (NT); roughening with a fine (FDB); medium (MDB); coarse-grit (CDB) and 50-μm aluminium oxide sandblasting (AO). A hydrophobic (Adhesive, Scotchbond Multi-Purpose Plus, 3M ESPE) or hydrophilic (Adper Single Bond 2, 3M ESPE) adhesive was applied, followed by composite placement (Opallis, FGM). Composite-composite bonded sticks (0.9 mm2) were tested in tension (1.0mm/min) immediately [IM] or after 6 months [6M] of water storage. Two sticks from each tooth, at each time, were immersed in a 50% silver nitrate solution and evaluated by SEM. A profilometer was used to measure SR. SEM images were used to estimate the SA using the Image J software. Data were analysed by ANOVA and Tukey's tests.

RESULTS

The AO showed the highest CR strength for both adhesives, whilst the NT group showed the lowest, irrespective of the storage period. The diamond burs had intermediate performance. Silver nitrate deposits were seen after 6M for the hydrophilic adhesive. The ranking of SR values (Ra) from the lowest to the highest was: NT<FDB<MDB<AO≤CDB. A higher SA was produced by AO treatment.

CONCLUSIONS

The AO treatment provides the highest CR strength likely due to the high SA produced. The bonding agent did not seem to affect the CR strength after 6M, although early signs of degradation were detected for the hydrophilic system.

CLINICAL SIGNIFICANCE

Polished composite should be preferred roughened with aluminium oxide followed by the application of a hydrophobic intermediate agent before composite repair.

Teaching of direct composite restoration repair in undergraduate dental schools in the United Kingdom and Ireland

AIM

To investigate aspects of the teaching of restoration repair as a minimally invasive alternative to the replacement of defective direct composite restorations in teaching programmes in undergraduate curricula in dental schools in the United Kingdom and Ireland.

METHODS

An online questionnaire which sought information in relation to the current teaching of composite restoration repair was developed and distributed to the 17 established UK and Irish dental schools with undergraduate teaching programmes in Spring 2010.

RESULTS

Completed responses were received from all 17 schools (response rate= 100%). Fifteen schools reported that they included teaching of repair techniques for defective direct composite restorations in their programme. Of the two remaining schools, one indicated that it would introduce teaching of repair techniques during the next five years. The most common indication for a composite repair was that of 'tooth substance preservation' (15 schools). The defects in restorations considered appropriate for repair rather than replacement by the largest number of schools included partial loss of restoration (13 schools) and marginal defects (12 schools). The most commonly taught surface treatment when performing a repair was mechanical roughening of the existing composite with removal of the surface layer (14 schools). Thirteen schools taught etching and the application of an adhesive bonding agent to the prepared surfaces, while the most commonly taught material for completing the repair was a hybrid composite resin (12 schools). Popular finishing implements included diamond finishing instruments (13 schools) and finishing discs (11 schools).

CONCLUSION

Not withstanding reluctance amongst general dental practitioners, the teaching of repair of a defective composite restoration, rather than total restoration replacement, is firmly established within UK and Irish dental school programmes. Repair techniques have clear advantages for patients, not least including a minimally invasive approach to treatment and avoidance of unnecessary loss of tooth tissue and pulpal damage. Dental practitioners should look more to repair techniques when managing defective composite restorations and clinical dental teachers should continue to research and refine composite repair techniques.

The Opinions of Manufacturers of Resin-Based Composite Materials towards the Repair of Failing Composite Restorations

Aim

To investigate the opinions of manufacturers of resin-based composite (RBC) towards the repair of their materials.

Methods

Representatives of 20 manufacturers of RBC were electronically mailed a questionnaire seeking information on aspects of the repair of direct composite restorations.

Results

The response rate was 100%. The findings indicated that although the majority of respondents regarded repair as a viable option for managing failing direct RBC restorations, marked variations were found to exist regarding recommendations for and contra-indications to performing repairs of RBC restorations.

Conclusions

Within the limitations of the current study, the following conclusions can be drawn: (1) the majority of manufacturers of RBC materials are aware and in favour of repair as opposed to replacement of defective composite restorations; (2) there is a need for manufacturers to produce guidelines for repair of their materials; and (3) there is a need for robust randomised controlled dental practice-based clinical studies in the field of repair of composite restorations.

Composite veneering of complex amalgam restorations

In large posterior cavities, indirect restorations could provide improved performance when compared to direct restorations, but with higher cost and removal of sound tooth structure. Improved mechanical properties have resulted in good clinical performance for amalgam in large cavities but without an esthetic appearance. Resin composites have become popular for posterior restorations, mainly because of good esthetic results. A restorative technique is presented that combines the esthetic properties of directly bonded resin composite and the wide range of indications for amalgam in stress-bearing areas.

Recommendations for conducting controlled clinical studies of dental restorative materials

About 35 years ago, Ryge provided a practical approach to evaluation of clinical performance of restorative materials. This systematic approach was soon universally accepted. While that methodology has served us well, a large number of scientific methodologies and more detailed questions have arisen that require more rigor. Current restorative materials have vastly improved clinical performance and any changes over time are not easily detected by the limited sensitivity of the Ryge criteria in short term clinical investigations. However, the clinical evaluation of restorations not only involves the restorative material per se but also different operative techniques. For instance, a composite resin may show good longevity data when applied in conventional cavities but not in modified operative approaches. Insensitivity, combined with the continually evolving and non-standard investigator modifications of the categories, scales, and reporting methods, has created a body of literature that is extremely difficult to meaningfully interpret. In many cases, the insensitivity of the original Ryge methods is misinterpreted as good clinical performance. While there are many good features of the original system, it is now time to move to a more contemporary one. The current review approaches this challenge in two ways: (1) a proposal for a modern clinical testing protocol for controlled clinical trials, and (2) an in-depth discussion of relevant clinical evaluation parameters, providing 84 references that are primarily related to issues or problems for clinical research trials. Together, these two parts offer a standard for the clinical testing of restorative materials/procedures and provide significant guidance for research teams in the design and conduct of contemporary clinical trials. Part 1 of the review considers the recruitment of subjects, restorations per subject, clinical events, validity versus bias, legal and regulatory aspects, rationales for clinical trial designs, guidelines for design, randomization, number of subjects, characteristics of participants, clinical assessment, standards and calibration, categories for assessment, criteria for evaluation, and supplemental documentation. Part 2 of the review considers categories of assessment for esthetic evaluation, functional assessment, biological responses to restorative materials, and statistical analysis of results. The overall review represents a considerable effort to include a range of clinical research interests over the past years. As part of the recognition of the importance of these suggestions, the review is being published simultaneously in identical form in both the "Journal of Adhesive Dentistry" and the "Clinical Oral Investigations." Additionally an extended abstract will be published in the "International Dental Journal" giving a link to the web full version. This should help to introduce these considerations more quickly to the scientific community.

Effect of oxygen inhibition on composite repair strength over time

The study was aimed at examining whether an oxygen inhibition layer is required for bonding a repairing to a pre-existing composite, and to determine the time required for free radicals within a composite substrate to decay to the extent that the composite repair strength drops significantly. Ten slabs of Gradia Direct Anterior (GC Corp.) were divided into (1) control group: an interfacial oxygen inhibition layer was created by applying and light-curing two layers of bonding resin (D/E Resin, Bisco) to the slabs surface in atmospheric air; (2) experimental group: the absence of an interfacial oxygen inhibition layer was obtained by light-curing the second bonding resin layer in a nitrogen atmosphere. After 1 and 2 h, 1, 14, and 30 days of air storage, a composite repair was layered over the bonding resin. Microtensile bond strengths were measured and statistically analyzed. The curing atmosphere was not a significant factor for bond strength (p = 0.82), and time and curing atmosphere-time interaction were significant (p < 0.001). The 30 day-strengths were the lowest (p < 0.05). An oxygen-inhibited layer is not initially required for bonding to resin composite, and it takes more than 14 days before the bond strength between a pre-existing and a fresh composite drops.

Clinical diagnosis of recurrent caries

BACKGROUND

The clinical diagnosis of recurrent caries is the most common reason for replacement of all types of restorations in general dental practice. Marked variations in the diagnosis of the lesions have been reported. The prevention of recurrent lesions by the use of fluoride-releasing restorative materials has not been successful.

TYPES OF STUDIES REVIEWED

The author focused on practice-based studies in the literature. These studies are not scientifically rigorous, but they reflect "real-life" dental practice. Few experimental studies on recurrent carious lesions in vivo have been reported, but bacteriological studies indicate that the etiology is similar to that of primary caries.

RESULTS

Recurrent carious lesions are most often located on the gingival margins of Class II through V restorations. Recurrent caries is rarely diagnosed on Class I restorations. The diagnosis is difficult, and it is important to differentiate recurrent carious lesions from stained margins on resin-based composite restorations. Over-hangs, even minute in size, are predisposed to plaque accumulation and the development of recurrent caries. The development of recurrent lesions is unrelated to microleakage.

CLINICAL IMPLICATIONS

As recurrent carious lesions are localized and limited, alternative treatments to restoration replacement are suggested. Polishing may be sufficient. If not, exploratory preparations into the restorative material adjacent to the localized defect can reveal the extent of the lesion. Such explorations invariably show that the lesion does not progress along the tooth-restoration interface. The defect, therefore, may be repaired in lieu of being completely replaced. Repair and refurbishing of restorations save tooth structure. These simple procedures also increase the life span of the restoration.

A cohort investigation of the changes in vocational dental practitioners' views on repairing defective direct composite restorations

OBJECTIVE

To investigate changes in vocational dental practitioners (VDPs) views on repairing direct composite restorations (DCRs) during the vocational training (VT) year 2002-2003.

DESIGN

A questionnaire-based cohort study.

METHOD

Data on the repair of DCRs, including indications and details of operative techniques were collected by a questionnaire sent at the beginning of the VT year (September 2002) to all 12 Postgraduate Dental Deans in England. A follow-up questionnaire was sent to the Deans near the end of the VT year (May 2003). They were asked, on both occasions, to distribute the questionnaires among their VDPs and to return the completed questionnaires.

RESULTS

Ten deaneries participated in the study. The September 2002 and May 2003 findings (306 respondents [66%] and 313 respondents [67%] respectively) were analysed using Chi-square statistic and t-test to identify any significant differences (P<0.05). Significant changes in the attitudes of the VDPs during the VT year included a shift to viewing reduction in treatment time (30% to 48%), cost to patient (12% to 20%) and the management of the partial loss of a restoration (57% to 70%) as indications for repairs. In contrast, there was a significant change in viewing secondary caries as an indication for repair (46% to 29%). In addition, there was a significant, worrisome shift in relation to the use of bonding systems and finishing instruments, together with a reduction in the anticipated longevity of composite repairs.

CONCLUSION

Aspects of VDPs' attitudes to the repair of DCRs were found to change significantly during the VT year. Not all aspects of the changes observed were considered to be positive. Knowledge and understanding of repairs to DCRs need to be strengthened.

Can a single composite resin serve all purposes?

The consensus view less than a decade ago was that direct posterior composites should be restricted to small restorations, preferably in premolar teeth with little, if any, occlusal function. Major advances in adhesive systems, materials and restorative techniques have combined to allow us to question this view and our increased clinical evidence base makes it appropriate to reconsider this viewpoint.

Cariology in Japanese dental schools

AIM

The aim of this study was to evaluate the teaching of cariology in Japanese dental schools.

DESIGN

Postal questionnaires were sent to all Japanese dental schools.

PARTICIPANTS

Twenty-five of the 29 Japanese dental schools (response rate: 86%).

RESULTS

The results were in many areas similar to those reported from North America. The non-surgical approach to the management of primary caries predominated, but no schools used bacteriological tests in caries diagnosis and only one school recommended antibacterial treatment. Four of the 25 responding schools advocated the treatment of primary enamel lesions by surgical intervention while three awaited operative intervention until the lesions had reached the middle third of the dentine. Recommendation of fluoride treatment was less common than in North America. The use of electronic devices to diagnose occlusal caries lesions was more common than in North America, but 'explorer catch' was the most frequently used method to diagnose primary and secondary caries in dental schools in both regions.

CONCLUSION

Research in cariology over the years has led to altered views on how and when to treat caries lesions. The interpretation of research findings and the transfer of knowledge by teachers in dental schools have an impact on the practice of operative dentistry, but the diversity in the teaching of cariology indicates that the interpretation and implementation of modern principles in the treatment of caries differ quite markedly in Japanese dental schools.

Curricular issues changing from amalgam to tooth-coloured materials

OBJECTIVE

To provide an overview of curriculum issues in changing from amalgam to tooth-coloured materials.

KEY POINTS

Changing from amalgam to tooth-coloured materials in teaching the restoration of posterior teeth may be found to have a considerable enriching effect on the dental curriculum. Subject to meeting a number of prerequisites, the change from amalgam to tooth-coloured materials may cause relatively little curriculum disruption, with the added bonus of a consequential shift from reparative to preservative, minimal invasive dentistry.

CONCLUSION

Changing from amalgam to tooth-coloured materials may enrich the typical dental curriculum.

Teaching students the repair of resin-based composite restorations: a survey of North American dental schools

BACKGROUND

The purpose of this study was to evaluate whether North American dental schools teach students to repair resin-based composite, or RBC, restorations and to compare the findings with those from similar European surveys.

MATERIALS AND METHODS

The authors mailed a 15-item questionnaire to 64 dental schools in the United States, Canada and Puerto Rico. The survey asked whether the school taught repair of RBC restorations and inquired about the respondent's experience with such procedures. Questions also elicited reasons why schools taught or did not teach repair, information in regard to relevant decision-making processes, criteria for deciding whether to perform repairs and the nature of the instruction (theoretical, practical, preclinical or clinical).

RESULTS

Fifty-two (81 percent) of 64 schools participated in the survey. Thirty-seven (71 percent) of the respondents reported that they taught undergraduate students repair techniques as an alternative to replacing failing RBC restorations. Twenty-seven (73 percent) of these 37 schools reported that such teaching was at the clinical level, while only three schools (8 percent) reported that it was included in formal lectures as part of preclinical courses. The major reasons given for teaching students how to repair RBC restorations were tooth structure preservation and reduction of potentially harmful effects on the pulp. Indications included the correction of marginal defect and marginal discoloration.

CONCLUSIONS

More than one-half of the respondents reported that they taught repair of RBC restorations and that patients were willing to accept such treatment. Most schools considered the repair of RBC restorations to be a definitive measure and reported that, on average, expected a repaired RBC restoration to have a longevity of four years.