Repair or replacement of restorations: do we accept built in obsolescence or do we improve the evidence?

Risk of failure of repaired versus replaced defective direct restorations in permanent teeth: a systematic review and meta-analysis

OBJECTIVE

This study aimed to systematically review the literature to compare the risk of failure of repaired and replaced defective direct resin composite and amalgam restorations performed in permanent teeth.

MATERIALS AND METHODS

The PubMed/MEDLINE, Scopus, Lilacs, BBO, Web of Science, SciELO, Cochrane Central Register of Controlled Trials (CENTRAL) databases, and gray literature were searched to identify longitudinal clinical studies related to the research question. No publication year or language restriction was considered. Two authors independently selected the studies, extracted the data, and assessed the risk of bias and certainty of evidence. A meta-analysis was performed using a fixed effects model at a 5% significance level.

RESULTS

From 1224 potentially eligible studies, thirteen were selected for full-text analysis, and three were included in the systematic review and meta-analysis. There was no difference in the risk of failure of repaired and replaced defective direct restorations (RR: 1.21, 95% CI: 0.51-2.83), either for resin composite (p = 0.97) or amalgam (p = 0.51) restorations. The risk of bias was high and the certainty of evidence was very low.

CONCLUSION

Based on the very low certainty of evidence, the repair of direct restorations does not present a significant difference in the risk of failure when compared to replacements in permanent teeth.

CLINICAL RELEVANCE

Restoration repair is a procedure that is included in the minimal intervention principle for improvement of tooth longevity in that the risk of failure of repaired partially defective restorations in permanent teeth seems similar to that of replacement. Further studies are required before definitive conclusions can be drawn.

Fatigue behavior and damage modes of high performance poly-ether-ketone-ketone PEKK bilayered crowns

OBJECTIVES

To evaluate and compare the fatigue behavior (fatigue limit and fatigue life) and damage modes of high-performance poly-ether-ketone-ketone (PEKK), zirconia and alloy bilayered crowns.

MATERIALS AND METHODS

A total of 110 crowns (n = 50 for fatigue limit and n = 60 for fatigue life) were fabricated and used in this study. Pekkton® ivory discs, yttrium stabilized zirconia blanks and NiCr casting alloy were used to produce the respective PEKK, zirconia and alloy copings for crown fabrication. The prepared crowns were veneered with composite resin and subjected to fatigue tests. The fatigue limit was evaluated using the staircase method and the fatigue life of the samples was evaluated by subjecting the crowns to a load lower than the fatigue limit of that particular group, and also with an intermediate load of 522 N. A graphical plot was generated from the shape parameter (β) and life parameter (α) values obtained through the Weibull analysis method. Kruskal-Wallis and Mann-Whitney tests were applied to determine the significance differences in the recorded fracture mode between the study groups. The damage modes of the samples were assessed using Burke's classification.

RESULTS

The recorded fatigue limits of the groups were 442.8 ± 42.1 N, 608.7 ± 7.6 N, and 790.4 ± 29.2 N for zirconia, NiCr and PEKK, respectively. A significant difference in the fatigue limit of the groups was observed (p < 0.05). PEKK samples demonstrated the highest survival cycles of 1,170,000 and the lowest survival cycles was observed with zirconia samples at 100,000 under 522 N loading. The fracture modes in PEKK samples were largely distributed between code 1 and 2 whereas the fracture modes in NiCr group was distributed between code 1 and 4 and YZ crowns exhibited more of code 5 fractures. The difference in fracture modes among the groups was statistically significant (p < 0.05).

CONCLUSION

The PEKK group demonstrated better results compared to zirconia and NiCr based crowns. The PEKK group demonstrated high fatigue limit and survived the highest fatigue life cycles among the tested groups.

Does use of silane-containing universal adhesive eliminate the need for silane application in direct composite repair?

This in vitro study aimed to evaluate the effect of a silane-containing universal adhesive used with or without a silane agent on the repair bond strength between aged and new composites. Forty nanohybrid composite resin blocks were stored in distilled water for 14 d and thermo-cycled. Sandpaper ground, etched, and rinsed speciments were randomly assigned into four experimental groups: silane + two-step etch-and-rinse adhesive system, two-step etch-and-rinse adhesive system, silane + silane-containing universal adhesive system, and silane-containing universal adhesive system. Blocks were repaired using the same composite. After 24 h of water storage, the blocks were sectioned and bonded sticks were submitted to microtensile testing. Ten unaged, non-repaired composite blocks were used as a reference group to evaluate the cohesive strength of the composite. Two-way ANOVA and Tukey's tests were used to analyze average µTBS. One-way ANOVA and Dunnet post-hoc tests were used to compare the cohesive strength values and bond strength obtained in the repaired groups (α = 0.05). The µTBS values were higher for the silane-containing universal adhesive compared to the two-step etch-and-rinse adhesive system (p = 0.002). Silane application improved the repair bond strength (p = 0.03). The repair bond strength ranged from 39.3 to 65.8% of the cohesive strength of the reference group. Using universal silane-containing adhesive improved the repair bond strength of composite resin compared to two-step etch-and-rinse adhesive. However, it still required prior application of a silane agent for best direct composite resin repair outcomes.

Same, same, but different? A systematic review of protocols for restoration repair

OBJECTIVES

While repairs are increasingly recommended to manage partially defective restorations, performing the repair (including bonding to different substrates) can be challenging, and dentists should adhere to established repair protocols. We aimed to systematically assess the consistency and quality of repair protocols.

DATA

808 records were initially identified and 71 repair protocols based on 84 sources included. The number of published sources over time increased exponentially (p < 0.001). Recommended treatment steps varied widely. Some treatment steps were only recommended by a minority of protocols, while others were consistently recommended (e.g. surface roughening, hydrofluoric acid etching of silicate ceramics, application of an adhesive/bonding agent). The overall quality of included sources was moderate (mean ± SD 3.7 ± 0.9 out of 7 points).

SOURCES

Electronic databases (Medline via PubMed, Embase) were searched, hand searches using Google and Google Scholar conducted, and the reference lists of included full texts screened and cross-referenced.

STUDY SELECTION

(Non-)systematic reviews, working instructions, and textbooks with protocols on direct composite repair restorations for partially defective (1) composite, (2) amalgam, (3) porcelain-fused-to-metal (PFMs) with exposed metal base, (4) ceramic/PFMs without exposed metal base, and (5) full metal restorations were included. Data synthesis was performed by tabulation of recommended treatment steps and descriptive statistics. The quality of included sources was assessed based on a checklist for guideline appraisal (MiChe).

CONCLUSIONS

The main treatment steps were consistently reported across repair protocols.

CLINICAL SIGNIFICANCE

Dentists may want to adopt widely recommended treatment steps when performing repairs of different restoration materials in their daily practice.

Repair increases the survival of failed primary teeth restorations in high-caries risk children: a university-based retrospective study

OBJECTIVES

We investigated factors associated with failure of adhesive restorations in primary teeth and whether repair may increase the survival of failed restorations placed in high-caries risk children.

MATERIALS AND METHODS

The sample comprised children who attended a university dental service to perform restorative treatment in primary teeth. Data were collected retrospectively from clinical records to assess the longevity of restorations. The outcomes were calculated in two levels: "Success" (Level 1)-when any re-intervention was considered as failure; "Survival" (Level 2)-when repaired restorations were considered clinically acceptable. The Kaplan-Meier survival test was used to analyze the longevity of restorations. Multivariate Cox regression with shared frailty was used to assess factors associated with failures (p < 0.05).

RESULTS

A total of 584 primary teeth restorations (178 patients) were included in the analysis. The longevity of restorations up to 36 months (Level 1) was 34.8% (AFR 29.6%). Multi-surface restorations showed significantly more failures than single-surface ones (HR 1.69; 95% CI 1.18, 2.41), and endodontically treated teeth presented more failures compared to vital teeth (HR 2.22; 95% CI 1.35, 3.65). There was an increase in restoration survival when repair was not considered as failure (p < 0.001). The survival of repaired restorations (Level 2) reached 43.7% (AFR 24.1%).

CONCLUSIONS

Adhesive restorations placed in primary teeth of high-caries risk children showed restricted longevity; however, the repair of failed restorations has increased its survival over time.

CLINICAL RELEVANCE

Repair is a more conservative and technically simple procedure that increases the survival of failed restorations in primary teeth.

Medical Model in Caries Management

The current mode of dental caries management mainly operates through irreversible and symptomatic treatment by means of drilling and filling, while caries prevention is largely overlooked or omitted. Focus should be redirected through a medical model towards elimination of the disease through tackling its causes and risk factors to address current and future caries initiation. Caries is the demineralisation of dental hard tissues by bacterial acids when periodically exposed to fermentable carbohydrates. The medical model of caries management is a philosophy that steers sustainable caries management through controlling bacterial infection, a reduction of risk levels, remineralisation of teeth and long-term follow-up. Its goal is to prevent new and recurrent caries, arrest ongoing caries processes by alteration of the cariogenic environment, and support the healing of remineralisable enamel and dentine. The mechanism involves dietary counselling and plaque control, placement of dental sealants, administration of fluoride agents and chemotherapeutic medications and use of chewing gum. This paradigm shift from a surgical to a medical model aims to pursue the ultimate intention of maintaining a caries-free dentition and is anticipated to promote true oral health-related quality of life. The objective of this paper is to discuss the medical model of caries management.

Dento-legal considerations about an MI approach

Over the years there have been many conceptual changes in how dental disease is prevented and managed. What is now the norm and standard practice was at some earlier time considered to be at best pioneering, and at its worst, heresy or negligent. When we look, for example at how we conservatively manage periodontal disease when less than a generation ago we were wielding surgical knives far more frequently than we do now, we can see how research and evidence-based dentistry has influenced our thinking. We are very much at that tipping point now with minimum intervention (MI) dentistry. This article will discuss the impact of MI dentistry from a legal viewpoint, covering such aspects as consent and record-keeping.

Seal, replacement or monitoring amalgam restorations with occlusal marginal defects? Results of a 10-year clinical trial

The aim of this prospective and blind clinical trial was to assess the effectiveness of sealing localized marginal defects of amalgam restoration that were initially scheduled to be replaced. A cohort of twenty six patients with 60 amalgam restorations (n=44Class I and n=16Class II), that presented marginal defects deviating from ideal (Bravo) according to USPHS criteria, were assigned to either sealing or replacement groups: A: sealing n=20, Replacement n=20, and no treatment (n=20). Two blind examiners evaluated the restorations at baseline (K=0.74) and after ten years (K=0.84) according with USPHS criteria, in four parameters: marginal adaptation (MA), secondary caries (SC), marginal staining (MS) and teeth sensitivity (TS). Multiple comparison of restorations degradation/upgrade was analyzed by Friedman test and the comparisons within groups were performed by Wilcoxon test. After 10 years, 44 restorations were assessed (73.3%), Group A: n=14 and Group B: n=16; and Group C: n=14 sealing and replacement amalgam restorations presented similar level of quality in MA (p=0.76), SC (p=0.25) and TS (p=0.52), while in MS (p=0.007) presented better performance in replacement group after 10-years. Most of the occlusal amalgam restorations with marginal gaps showed similar long term outcomes than the restorations were sealed, replaced, or not treated over a 10-year period. Most of the restorations of the three groups were clinically acceptable, under the studied parameters. All restorations had the tendency to present downgrade/deterioration over time.

Xylitol-containing products for preventing dental caries in children and adults

BACKGROUND

Dental caries is a highly prevalent chronic disease which affects the majority of people. It has been postulated that the consumption of xylitol could help to prevent caries. The evidence on the effects of xylitol products is not clear and therefore it is important to summarise the available evidence to determine its effectiveness and safety.

OBJECTIVES

To assess the effects of different xylitol-containing products for the prevention of dental caries in children and adults.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group Trials Register (to 14 August 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2014, Issue 7), MEDLINE via OVID (1946 to 14 August 2014), EMBASE via OVID (1980 to 14 August 2014), CINAHL via EBSCO (1980 to 14 August 2014), Web of Science Conference Proceedings (1990 to 14 August 2014), Proquest Dissertations and Theses (1861 to 14 August 2014). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of xylitol products on dental caries in children and adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies. We attempted to contact study authors for missing data or clarification where feasible. For continuous outcomes, we used means and standard deviations to obtain the mean difference and 95% confidence interval (CI). We used the continuous data to calculate prevented fractions (PF) and 95% CIs to summarise the percentage reduction in caries. For dichotomous outcomes, we reported risk ratios (RR) and 95% CIs. As there were less than four studies included in the meta-analysis, we used a fixed-effect model. We planned to use a random-effects model in the event that there were four or more studies in a meta-analysis.

MAIN RESULTS

We included 10 studies that analysed a total of 5903 participants. One study was assessed as being at low risk of bias, two were assessed as being at unclear risk of bias, with the remaining seven being at high risk of bias.The main finding of the review was that, over 2.5 to 3 years of use, a fluoride toothpaste containing 10% xylitol may reduce caries by 13% when compared to a fluoride-only toothpaste (PF -0.13, 95% CI -0.18 to -0.08, 4216 children analysed, low-quality evidence).The remaining evidence on children, from small single studies with risk of bias issues and great uncertainty associated with the effect estimates, was insufficient to determine a benefit from xylitol products. One study reported that xylitol syrup (8 g per day) reduced caries by 58% (95% CI 33% to 83%, 94 infants analysed, low quality evidence) when compared to a low-dose xylitol syrup (2.67 g per day) consumed for 1 year.The following results had 95% CIs that were compatible with both a reduction and an increase in caries associated with xylitol: xylitol lozenges versus no treatment in children (very low quality body of evidence); xylitol sucking tablets versus no treatment in infants (very low quality body of evidence); xylitol tablets versus control (sorbitol) tablets in infants (very low quality body of evidence); xylitol wipes versus control wipes in infants (low quality body of evidence).There was only one study investigating the effects of xylitol lozenges, when compared to control lozenges, in adults (low quality body of evidence). The effect estimate had a 95% CI that was compatible with both a reduction and an increase in caries associated with xylitol.Four studies reported that there were no adverse effects from any of the interventions. Two studies reported similar rates of adverse effects between study arms. The remaining studies either mentioned adverse effects but did not report any usable data, or did not mention them at all. Adverse effects include sores in the mouth, cramps, bloating, constipation, flatulence, and loose stool or diarrhoea.

AUTHORS' CONCLUSIONS

We found some low quality evidence to suggest that fluoride toothpaste containing xylitol may be more effective than fluoride-only toothpaste for preventing caries in the permanent teeth of children, and that there are no associated adverse-effects from such toothpastes. The effect estimate should be interpreted with caution due to high risk of bias and the fact that it results from two studies that were carried out by the same authors in the same population. The remaining evidence we found is of low to very low quality and is insufficient to determine whether any other xylitol-containing products can prevent caries in infants, older children, or adults.

Dentists' restorative decision-making and implications for an 'amalgamless' profession. Part 1: a review

The Minamata Convention has agreed to a worldwide reduction and ultimate elimination in the production and use of mercury containing products. This will have implications for the practice of dentistry. Australian organizations' pronouncements on the issue are limited and research examining the Australian context dated. The restoration of teeth with direct materials has changed significantly since the 1980s. Up to this time amalgam was the material of choice for direct posterior restorations. Its properties and guidelines for placement were, and remain, well established. Resin composite has replaced amalgam as the material of choice in many clinical situations. Despite inherent clinical disadvantages compared to amalgam, there continues to be a shift toward greater use of resin composite. There is consensus worldwide that the restoration of posterior teeth using resin composite now exceeds that of amalgam. The reasons for this are reviewed in this article along with current evidence and commentary relating to direct restorative and evidence-based decision-making, minimally invasive approaches, and approaches to education. The implications for these in an 'amalgamless' profession are identified.

The reparability of contemporary composite resins

Objective:

The objective was to investigate the way that various surface treatments could influence the bond strength of the repair of methacrylate (MC) and silorane (SIL) composites.

Materials and Methods:

A total of 160 MC and SIL cylindrical specimens were polymerized and aged in artificial saliva solution for 7 days. Depending on the following surface treatment (diamond bur or air abrasion), and the conditioning procedure (orthophosphoric acid or sodium hypochlorite), 16 groups were formed and repaired either with MC, either with SIL composite. Repaired specimens were subjected to an additional aging procedure in artificial saliva for 7 days, followed by thermo-cycling and then stressed in shear at a rate of 0.5 mm/min until failure. Failure patterns were analyzed using stereomicroscope and scanning electron microscopy.

Results:

MC composite showed statistically significant higher bond strength both as a base or repair material than SIL (P < 0.001). Statistically significant differences were not observed, when grinding and conditioning procedures was compared. Pretest failures were observed when aged MC-based composite was repaired with SIL-based.

Conclusions:

Type of composite seems to be the main factor influencing the bond strength of the repair. MC-based composite showed better repairability than SIL composite. Optimum repair conditions should include knowledge of the composite's composition.

Translating research into everyday clinical practice: lessons learned from a USA dental practice-based research network

OBJECTIVES

This paper discusses practice-based research (PBR) as a means to speed up the translation of research findings to clinical practice. It also reviews repair versus replacement of defective restorations as one example of the delay in the application of research findings to clinical practice.

METHODS

Despite the existence of clinical studies, a significant delay exists between the generation of new knowledge and its application into the medical/dental community and their patients. One example is the repair of defective dental restorations. About 75% of practitioners in general dental practices do not consider the repair of dental restorations as a viable alternative to the replacement of defective restorations. Engaging and partnering with health practitioners in the field on studies addressing everyday clinical research questions may offer a solution to speed up the translation of the research findings.

RESULTS

Practice-based research (PBR) offers a unique opportunity for practitioners to be involved in the research process, formulating clinical research questions. Additionally, PBR generates evidence-based knowledge with a broader spectrum that can be more readily generalized to the public. With PBR, clinicians are involved in the entire research process from its inception to its dissemination.

SIGNIFICANCE

Early practitioner interaction in the research process may result in ideas being more readily incorporated into practice. Clinical studies are of paramount importance for testing and translation of the research findings to the community.

The influence of long term water immersion on shear bond strength of amalgam repaired by resin composite and mediated by adhesives or resin modified glass ionomers

OBJECTIVE

To assess the shear bond strength between amalgam and resin composite mediated by either multipurpose adhesive systems or RMGI when subjected to long term immersion in saline.

METHODS

Part I: Cylindrical specimens (6 mm × 6 mm) composed of equal parts of sandblasted set amalgam (Oralloy) and composite (Z-100), with a thin layer of either Scotchbond Multipurpose, All Bond 2, Amalgam Bond Plus, High Q Bond Plus or Vitrebond in between were fabricated (n = 100 × 5). Each group was divided into 3 subgroups, immersed in saline at 37 °C for either 48 h, 3 or 6 months, followed by thermocycling (5000; 5/55 °C) and shear bond strength testing (SBS). Part II: Identical specimens were fabricated with intermediary of either Ketac Cem, Fuji Lining LC, Rely X Luting, Fuji Plus or Meron Plus (n = 100 × 5). Immersion periods, followed by thermocycling and SBS testing as in Part I. Two representative specimens from each subgroup were sectioned and inspected under SEM.

RESULTS

The two classes of intermediary agents yielded SBS which differed mainly in the 6 months incubation period. While multipurpose adhesives provided SBS values of ~9-10 MPa RMGI provided higher SBS of ~16 MPa. All Bond 2 and Amalgam Bond Plus exhibited deterioration of SBS during the 6 month period as well as Rely X Luting. Gap sizes between 0.5 and 3 μm exist between all intermediaries and the amalgam; on the other hand all intermediaries exhibit gap-free interfaces between the adhesives/RMGI and the composite.

CONCLUSIONS

Vitrebond in particular and RMGIs in general can serve as an excellent coupler of resin composite to amalgam, providing a durable bond.

Caries and the older patient

Ageing of the population, together with prolonged retention of teeth, has brought new challenges to dentistry. Whereas in the past oral care for the elderly was restricted to provision of dentures, older patients are now presenting with dental caries and failed restorations. These problems may have an impact on their general health and quality of life. Poor oral hygiene, xerostomia and diet are among the risk factors for caries in older patients and need to be addressed in order to achieve control of the disease. Carious lesions can be treated conservatively in many cases or may need surgical management.

CLINICAL RELEVANCE

Caries is an oral health issue among older patients and can result in tooth loss. Oral health has a great impact on general health and quality of life of elderly people.