Update on Enamel Bonding Strategies

Optimal strategies for the application of an adhesive differ between enamel and dentin because of the differences in their composition. The development of adhesive systems has mainly focused on the bonding of dentin, rather than on the enamel, by etching with phosphoric acid (PA). Dental adhesive technologies continue to rapidly advance, and various adhesive systems have been developed since the study of Buonocore in 1955. He introduced the enamel acid-etch technique. Then, the etch-and-rinse (ER) system was developed, and subsequently, the self-etch (SE) system. Universal adhesives are a new generation of one-bottle SE adhesives that can be applied with either ER mode or SE mode, or a combined system involving selective enamel etching mode. Since the combination of PA etching and the SE system differs from conventional ER systems, the enamel bonding strategy should be carefully considered. This concise review of the literature on reliable enamel bonding strategies should prove helpful to clinicians to choose an appropriate adhesive system to achieve optimal clinical outcomes.

Adhesive strategies in cervical lesions: systematic review and a network meta-analysis of randomized controlled trials

OBJECTIVES

A network meta-analysis (NMA) was performed to assess which adhesive strategy is most clinically effective in treating non-carious cervical lesions (NCCLs).

MATERIAL AND METHODS

Studies were identified by a systematic search of electronic databases including MEDLINE via PubMed, Brazilian Library in Dentistry (BBO), Cochrane Library, EMBASE, Latin American and Caribbean Health Sciences Literature database (LILACS), Scopus, and Web of Science without restrictions on publication year or language. The grey literature was also consulted. Only randomized clinical trials that compared different adhesive strategies in NCCLs in adult patients were included. The risk of bias was evaluated by using the Cochrane Collaboration tool. A random-effects Bayesian mixed treatment comparison model was used to compare adhesive strategies (3ER, 2ER, 2SE, and 1SE) at different follow-up times. The surface under cumulative ranking curve (SUCRA) was estimated for each strategy. Heterogeneity was assessed by using the Cochran Q test and I² statistics. The quality of evidence was evaluated using the GRADE approach.

RESULTS

A total of 5058 studies were identified, 66 of which met the eligibility criteria and of these 5 were judged "low" risk of bias and 57 were meta-analyzed. We did not observe significant differences in the NMA analysis for any two pairs of adhesives, except for the shortest follow-up for 2ER vs 3ER. The material 2SE ranked highest, although it differed only slightly from the other bonding strategies.

CONCLUSIONS

No bonding strategy is better than the others.

CLINICAL RELEVANCE

Adhesive efficacy cannot be characterized by its bonding strategy.

Clinical Efficiency of Self-etching One-Step and Two-Step Adhesives in NCCL: A Systematic Review and Meta-analysis

CLINICAL RELEVANCE

One-step self-etch adhesive systems provide a clinical time gain, decreasing the number of clinical steps. When a clinician is able to follow a simpler process of adhesion there is less chance of adhesive failure.

SUMMARY

Objective: A systematic review and meta-analyses were performed to evaluate whether one-step self-etching (1SSE) adhesive systems are as effective as two-step self-etching (2SSE) adhesives in noncarious cervical lesion (NCCL) restorations.Methods: This systematic review was conducted according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and recorded in the PROSPERO (CRD42018096747). Electronic systematic searches were conducted in the following databases: PubMed/MEDLINE, Scopus, and Cochrane Library for published articles. Only randomized clinical trials that compared 1SSE with 2SSE adhesives systems were selected. The outcomes were retention, postoperative sensitivity, secondary caries, color match, marginal discoloration, marginal adaptation, and anatomical form.Results: The searches resulted in 476 studies. After applying the eligibility criteria, five randomized controlled trials were selected in which 822 restorations in NCCLs were distributed in 237 patients. The results showed no statistical difference between 1SSE and 2SSE in relation to retention (p=0.23; relative risk [RR]=1.55; 95% confidence interval [CI]=0.76, 3.19), postoperative sensitivity ( p=0.50; RR=3.00; 95% CI=0.13, 70.64), Secondary caries (p=0.63; RR=0.68; 95% CI=0.14, 3.31), color match (p=0.41; RR=0.64; 95% CI=0.23, 1.83), marginal discoloration (p=0.93; RR=1.02; 95% CI=0.65, 1.61), and anatomical form (p=0.56; RR=1.38; 95% CI=0.46, 4.13). However there was statistical difference in relation to marginal adaptation ( p=0.01; RR=1.95; 95% CI=1.14, 3.34).Conclusion: This systematic review with meta-analysis revealed that both 1SSE and 2SSE adhesive systems have comparable clinical effectiveness in a follow-up period of 12 to 24 months, except in relation to marginal adaptation.

Effects of Zn-Doped Mesoporous Bioactive Glass Nanoparticles in Etch-and-Rinse Adhesive on the Microtensile Bond Strength

The purpose of this study was to assess the effects in the dentin bond strength of dental adhesives (DAs) and biological effects using zinc (Zn)-doped mesoporous bioactive glass nanoparticles (MBN-Zn). Synthesized MBN and MBN-Zn were characterized by scanning electron microscopy (SEM), X-ray diffraction and the Brunauer, Emmett and Teller (BET) method. The matrix metalloproteinases (MMP) inhibition effects of DA-MBN and DA-MBN-Zn were analyzed. The microtensile bond strength (MTBS) test was conducted before and after thermocycling to investigate the effects of MBN and MBN-Zn on the MTBS of DAs. The biological properties of DA-MBN and DA-MBN-Zn were analyzed with human dental pulp stem cells (hDPSCs). Compared with the DA, only the DA-1.0% MBN and DA-1.0% MBN-Zn exhibited a statistically significant decrease in MMP activity. The MTBS values after thermocycling were significantly increased in DA-1.0% MBN and DA-1.0% MBN-Zn compared with the DA (p < 0.05). It was confirmed via the MTT assay that there was no cytotoxicity for hDPSCs at 50% extract. In addition, significant increases in the alkaline phosphatase activity and Alizarin Red S staining were observed only in DA-1.0%MBN-Zn. These data suggest the 1.0% MBN and 1.0% MBN-Zn enhance the remineralization capability of DAs and stabilize the long-term MTBS of DAs by inhibiting MMPs.

Pure Ormocer vs Methacrylate Composites on Posterior Teeth: A Double-blinded Randomized Clinical Trial

CLINICAL RELEVANCE

The clinical behavior of pure ormocer composite is reliable when used in class II restorations after 24 months of evaluation.

SUMMARY

Two-year performance of CAD/CAM fabricated resin composite inlay restorations: A randomized controlled clinical trial

OBJECTIVE

The aim of this study was to evaluate the 2-year clinical performance of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite inlay restorations in comparison with direct resin composite restorations.

MATERIALS AND METHODS

In 44 patients, 120 class II (mesio-occlusal/disto-occlusal) cavities were randomly assigned into two groups; CAD/CAM resin composite inlay group (Lava Ultimate), direct resin composite group (Clearfil Majesty Posterior). Clinical evaluations were performed after 1 week, 6 months, 1 year, and 2 years according to the FDI criteria. The data were analyzed using Friedman's ANOVA and Mann-Whitney U tests (α = .05).

RESULTS

In 41 patients, 114 restorations were evaluated at the second year (recall rate 93.2%). All restorations were ideal or clinically acceptable. At the first year, considering all criteria, there were no statistically significant differences between the groups. However, there was a significant difference in terms of surface luster at second year, in favor of inlay restorations (P = .015). The marginal staining of resin composites increased after 2 years (P = .046), but there was no significant difference between the groups.

CONCLUSIONS

Except the surface luster, 2-year clinical performance of CAD/CAM resin composite inlay restorations was found similar to direct resin composite restorations according to FDI criteria CLINICAL SIGNIFICANCE: The clinical performance of CAD/CAM resin composite inlays was acceptable in class II cavities subsequent to 2-year evaluation.

Influence of adhesive strategy on clinical parameters in cervical restorations: A systematic review and meta-analysis

OBJECTIVES

We aimed to answer the following PICO question: "Is the risk of postoperative sensitivity (POS), retention rates and marginal discoloration of composite restorations [CR] bonded with self-etch (SE) in non-carious cervical lesions (NCCLs) of adults equals to etch-and-rinse (ER) adhesives?".

METHODS

A comprehensive search was performed in May 2016 in the MEDLINE, Scopus, Web of Science, LILACS, BBO and Cochrane Library and SIGLE, abstracts of IADR, unpublished and ongoing trials registries, dissertations and theses without restrictions. Only randomized clinical trials that compared composite resin restorations placed with self-etch and etch-and-rinse in NCCLs were included. After removal of duplicates and non-eligible articles, 50 articles from 42 studies (follow-ups of the same study were merged) remained for synthesis of the risk of bias (Cochrane Risk of bias tool).

RESULTS

Thirteen studies were at "high" risk of bias, yielding 29 studies for meta-analysis. No difference on the POS after restoration placement (risk ratio [RR] 1.04; 95% CI 0.81 to 1.34) as well as in the retention rates for all follow-up periods was observed. The etch-and-rinse approach produced less marginal discoloration at 18 months to 2 years (RR 1.51; 95% CI 1.21 to 1.90) and at 4 to 5 years (RR 1.81; 95% CI 1.28 to 2.55) (p<0.0007).

CONCLUSIONS

The adhesive strategy did not influence the POS and the retention rates of composite resin in NCCLs in any of the follow-up periods; but less marginal discoloration was found in etch-and-rinse adhesives.

CLINICAL SIGNIFICANCE

Composite resin restorations placed with self-etch and etch-and-rinse adhesives produce restoration with the similar clinical service and POS, however using etch-and-rinse adhesives one can reduce marginal discoloration. PROSPERO registration number: CRD42015019533.

Five-year clinical performance of the dentine deproteinization technique in non-carious cervical lesions

OBJECTIVE

The aim of this study was to evaluate the 5-year clinical performance of composite restorations of non-carious cervical lesions (NCCL) using a total-etch adhesive system with or without collagen removal with 10% sodium hypochlorite (NaOCl).

METHODS

In this study randomized controlled split-mouth clinical trial, one-hundred and thirty-eight NCCL were restored into 30 patients. Each patient received at least one pair of composite restorations (Filtek A110/3M ESPE), bonded either with 2 techniques: Conventional Technique--acid etching with 37% phosphoric acid+Prime & Bond NT (Denstply DeTrey); Deproteinization Technique--acid etching with 37% phosphoric acid+10% NaOCl for 1min+Prime & Bond NT. The two techniques were evaluated using the United States Public Health Service (USPHS) criteria at baseline, 18 months, 3 and 5 years. After five years, one-hundred and six restorations were evaluated in 24 patients. Data were analyzed using the Chi-Square test (p<0.05).

RESULTS

There were no statistically significant differences between the two techniques regarding the evaluated parameters (p>0.05).

CONCLUSION

After 5 years, the application of 10% NaOCl deproteinization on etched dentine did not affect the clinical performance of composite restorations placed in NCCL when compared to the conventional total-etch technique.

CLINICAL SIGNIFICANCE

Clinical studies evaluating the performance of the Deproteinization Technique are scarce. In this study, this technique showed similar clinical performance at the end of 5 years when compared to a conventional total-etch technique.

Five-year clinical performance of a HEMA-free one-step self-etch adhesive in noncarious cervical lesions

OBJECTIVES

The objective of this randomized controlled trial was to evaluate the clinical performance of a 2-hydroxyethyl methacrylate (HEMA)-free one-step adhesive.

MATERIALS AND METHODS

Two hundred sixty-seven cervical lesions in 52 patients were restored with the composite Gradia Direct (GC), bonded with either the one-step self-etch adhesive G-Bond (GC) or the three-step etch-and-rinse adhesive Optibond FL (Kerr) in a random order. The restorations were evaluated for retention, marginal integrity, marginal discoloration, and caries occurrence after 5 years. Specific statistics were used to account for the clustered data (multiple restorations per patient).

RESULTS

The clinical success rate for G-Bond (87.4 %) was not significantly different from that of Optibond FL (90.9 %). Both adhesives showed progressive marginal deterioration, but G-Bond exhibited more small enamel defects and marginal discoloration, and unlike previous recalls, several restorations failed because of deep microleakage. Large sclerotic lesions were a significant risk factor for retention loss with G-Bond. Irrespective of the adhesive, almost all restorations with retention loss were located in the lower jaw.

CONCLUSION

After 5 years of clinical service, restorations bonded with the HEMA-free one-step adhesive did not need repair or replacement more often than those with the three-step etch-and-rinse adhesive, and both adhesives had a high retention rate (>90 %). There were indications that G-Bond did not (self-)etch enough in some clinical situations, as G-Bond exhibited more incisal defects and marginal discolorations, and sclerotic lesions were at higher risk of retention loss.

CLINICAL RELEVANCE

The clinical performance of the HEMA-free one-step adhesive was clinically acceptable after 5 years.