Shear Bond Strength of Adhesives Placed following Selective Removal of Red-Fluorescing Carious Dentine in vitro.

Red-fluorescing dentine indicates bacterial contamination [Caries Res 2002; 36: 315-319]. We investigated effect of removal of red fluorescent dentine caries on shear bond strength and fracture mode of 4 adhesive approaches. Sixty-five carious teeth and 50 noncarious controls were distributed into 4 groups: Clearfil™ self-etch (CSE), OptiBond™ FL total etch (OTE), Scotchbond™ Universal total etch (STE) and self-etch (SSE). Samples were excited at 405 nm and viewed through 530 nm filter. Carious samples were ground flat exposing strongly red-fluorescing (StrongRF) dentine, on which a composite cylinder was placed, using one of 4 adhesives. After 22 h in water, shear bond strength and fracture mode were analysed. StrongRF was removed; composite cylinders were placed on weakly red-fluorescing (WeakRF) dentine and tested as described above. Finally, red-fluorescing dentine was removed, and composite cylinders were placed on non-fluorescing (NonRF) dentine and tested. Composites were placed at 3 corresponding heights in controls. After 22 h in water, shear bond strength testing and fracture mode analysis were performed. Differences were tested using Mann-Whitney or Wilcoxon tests (p ≤0.05). Median (Q1, Q3) shear bond strength on StrongRF was SSE 14.4 (9.2, 18.2) MPa >CSE 10.2 (6.4, 17.3) MPa >STE 9.1 (6.9, 11.2) MPa >OTE 6.8 (4.0, 10.8) MPa. Shear bond strength increased statistically significantly for all adhesives on WeakRF: SSE 19.8 (13.6, 24.3) MPa >STE 19.5 (12.7, 23.1) MPa >CSE 17.5 (12.0, 22.5) MPa >OTE 15.8 (11.9, 20.9) MPa. Only STE 25.6 (22.4, 29.1) MPa and CSE 22.1 (17.6, 24.6) MPa were significantly different on NonRF compared to WeakRF. For controls tested at corresponding depths, superficial shear bond strength was OTE 18.7 (16.0, 22.1) MPa >STE 18.4 (12.0, 25.9) MPa >CSE 18.1 (12.7, 20.7) MPa >SSE 13.0 (9.6, 17.8) MPa. This was significantly higher compared to StrongRF except for SSE. Central shear bond strength was not significantly different to WeakRF, deep shear bond strength was significantly lower for SSE and CSE but higher for OTE compared to carious. Conclusion: StrongRF dentine should be removed for higher shear bond strength, but WeakRF dentine can often be preserved without compromising adhesive bond strength.

A 2-Year Randomized Clinical Trial of Three Bonding Techniques in Non-Carious Cervical Lesions.

Background and objective: The aim of this randomized split-mouth study-controlled clinical trial was to compare the 2-year clinical performance of resin composite restorations placed at non-caries cervical lesions (NCCL) with one-step self-etch, total-etch, and selective enamel etch and self-etch adhesive techniques. Materials and methods: Thirty-two patients received three resin composite restorations each at NCCLs (Tetric EvoCeram/Ivoclar/Vivadent), bonded with a total-etch adhesive agent (ExciTE F/Ivoclar/Vivadent) and a self-etch (AdheSE One F/Ivoclar/Vivadent) without and with selective enamel etching. All restorations were evaluated by two examiners at baseline, 6-, 12-, 18-, and 24-months with FDI clinical criteria (post-operation regarding retention, caries occurrence, marginal adaptation, and marginal staining). A logistic regression analysis, a Cohen's kappa statistic, a multifactorial analysis, and X2 were performed with generalized estimating equations. Results: After 2 years, the retention rate was 86.8% for total etch, 92.26% for self-etch, and 93.63% for selective enamel etching and self-etch. No caries was detected on the restorations. Concerning marginal adaptation, the clinically perfect restorations were 26.9% for the total-etch technique, 16% for self-etch, and 25.9% for selective enamel etch and self-etch. The logistic regression model revealed that only time reduced the probability of perfect marginal adaptation. Conclusions: All three adhesive strategies provided restorations with no significant differences in the retention rate or marginal adaptation, whereas the total etch yielded better performance for marginal staining. All restorations were assessed as clinically acceptable after 2 years.

Comparative evaluation of effect of chlorhexidine application on dentin bond strength with two different adhesives after ER, CR: YSGG phototherapy: an in vitro study.

This study aimed to assess the efficacy of phototherapy with an Er, Cr:YSGG laser on the bond strength of dentin using two different adhesive systems after chlorhexidine (CHX) application. Twenty-four non-carious human molar teeth were separated into three main groups: negative control Group A (Group A), CHX and phototherapy with an Er, Cr:YSGG laser (Group PC), and CHX with conventional diamond bur (no phototherapy) (Group C). These groups were divided into two subgroups based on adhesives: Clearfil Universal Quick Bond and Clearfil SE Bond. To evaluate the microtensile bond strength, the occlusal enamel surfaces of the teeth were removed with a low-speed, water-cooled diamond bur to expose hard dentin tissue. The teeth within Group PC were treated with Er, Cr:YSGG phototherapy. The surfaces were then disinfected with 0.2% chlorhexidine gluconate. Subgroups were applied according to the manufacturer's instructions using the adhesive systems mentioned above. Following adhesive application, the teeth were restored with composite resin. A microtensile bond strength test was performed on the test sticks obtained from the teeth using a universal test device. Data were analyzed using variance analysis (ANOVA) at a significance level of p < 0.05. Among all groups, the highest bond strength was achieved with Clearfil SE Bond with CHX + phototherapy (45.6 ± 4.2), while the lowest was achieved with Clearfil Universal Quick Bond without phototherapy (control group) (27.0 ± 6.7) (p < 0.05). Phototherapy with Er, Cr: YSGG following chlorhexidine application enhanced the bond strength of both the bond systems (p < 0.05).

Development of a remineralizing calcium phosphate nanoparticle-containing self-etching system for orthodontic bonding.

OBJECTIVES: This study aimed to incorporate hydroxyapatite nanoparticles (nHA) or amorphous calcium phosphate nanoparticles (nACP) into a self-etch primer (SEP) to develop a simplified orthodontic bonding system with remineralizing and enamel preserving properties. MATERIALS AND METHODS: nHA and nACP were incorporated into a commercial SEP (Transbond™ plus) in 7% weight ratio and compared with the plain SEP as a control. Shear bond strengths (SBS), enamel damage, and adhesive remnant index (ARI) scores were evaluated at 24 h and post 5000 thermocycling. Field-emission scanning electron microscope (FESEM) was used to inspect the distribution of the nanoparticles in the experimental SEPs and evaluate the enamel surface integrity both before bracket bonding and post bracket debonding. Phase determination and remineralizing capability of the modified SEP were characterized by X-ray diffraction and Raman spectroscopy, respectively. RESULTS: The addition of nHA or nACP to the SEP significantly reduced the SBS, ARI, and enamel damage (p < 0.05) as compared to the control SEP; however, only nHA-SEP survived the thermocycling protocol and yielded acceptable SBS (13.38 MPa). Enamel remineralizing ability of the developed nHA-SEP was confirmed by both FESEM images and Raman phosphate map. CONCLUSIONS: Incorporating nHA into SEP resulted in clinically acceptable bond strengths with remineralizing ability. CLINICAL RELEVANCE: The newly developed nHA-SEP has unprecedented ability to simultaneously etch, prime, and remineralize the enamel in a single step leaving immaculate enamel surface with the potential of saving cost and time at the post-debonding step.

Effect of different adhesive systems on dental defects and sensitivity to teeth in composite resin restoration: a systematic review and meta-analysis.

OBJECTIVES: This meta-analysis aimed to elucidate the effects of various acid etching patterns on the sensitivity of teeth and their clinical effectiveness following composite resin repair. MATERIALS AND METHODS: PubMed, Cochrane Library, Web of Science, and Embase databases were searched for relevant studies on the postoperative sensitivity (POS) of composite resin restorations after using different bonding systems. The retrieval was from the inception of the databases to August 13, 2022, with no filter of written language. Literature screening was conducted by two independent researchers. The Cochrane risk-of-bias assessment tool was adopted for quality evaluation, and Stata 15.0 for analysis. RESULTS: Twenty-five randomized controlled trials were included in the present study. Following resin composite restoration, 1309 restorations were bonded by self-etching (SE) adhesives, whereas 1271 restorations were bonded by total-etching (TE) adhesives. The meta-analyses showed that there is no evidence to prove the SE and TE will affect POS at present when measured using the modified United States Public Health Service (USPHS) criteria [RR = 1.00 (95% CI: 0.96, 1.04)], the World Dental Federation (FDI) [RR = 1.06 (95% CI: 0.98, 1.15)], or the visual analog scale (VAS) [SMD = 0.02 (95% CI: -0.15, 0.20)] scales. At a certain follow-up time, TE adhesives provide better outcomes in terms of color match, marginal staining, and marginal adaptation. In other words, TE adhesives have better esthetic results. CONCLUSIONS: The type of bonding technique (ER and SE) does not affect the risk and degree of POS in class I/II and class V restorations. Further research is required to verify whether these findings apply to different forms of composite resin restorations. CLINICAL RELEVANCE: Besides the fact that TE barely increase postoperative sensitivity, it also yields superior cosmetic results.

The effect of dentin surface pretreatment using dimethyl sulfoxide on the bond strength of a universal bonding agent to dentin.

BACKGROUND: This study aimed to evaluate the effect of dentin pretreatment by Dimethyl Sulfoxide (DMSO) on the bond strength and microleakage of a universal bonding agent to dentin. METHODS: Fifty-six dentinal discs (thickness = 2 mm) were obtained from the crowns of the human third molars. The disks were assigned into 4 groups and treated as follows; self-etch-control group: G-Premio universal adhesive was used in self-etch mode, total-etch-control: G-Premio universal adhesive was used in total-etch mode, self-etch-DMSO: Water-based DMSO (50% volume) was applied on the samples for 60 s followed by application of G-Premio universal adhesive in self-etch mode, and Total-etch-DMSO: The samples were etched, and then, water-based DMSO was applied on them for 60 s followed by the application of G-Premio universal adhesive in total-etch mode. Afterward, resin composite was placed on all samples and light-cured. The samples were kept in distilled water and subjected to 5000 thermal cycles. Microshear bond strength was measured using the universal testing machine and failure modes were analyzed using a stereomicroscope. Forty-eight human third molars were used for microleakage evaluation and a standardized class five cavity was prepared on the buccal surface of each tooth. The teeth were assigned into 4 groups and received aforementioned surface treatment and the cavities were filled with resin composite. After storing in water for 24 h, the samples were subjected to 5000 cycles of thermocycling and the microleakage level of the samples was evaluated using silver nitrate uptake at the bonded interface. Two-way ANOVA test was used to analyze the effect of bonding technique (self-etch/ total-etch) and DMSO pretreatment on the microshear bond strength and microleakage of G-Premio adhesive to dentin. RESULTS: Bonding technique had no effect on the bond strength values (p = 0.17) while DMSO pretreatment significantly decreased the microshear bond strength of the samples (p = 0.001). DMSO application increased microleakage significantly in total-etch (P-value = 0.02) while it had no effect in self-etch mode (P-value = 0.44). CONCLUSIONS: Pretreatment of dentin using 50% DMSO significantly reduced the bond strength of G-Premio Bond in both self-etch and total-etch modes. DMSO effect on microleakage depended on the etching technique; DMSO increased the microleakage level when the adhesive was used in total-etch mode while did not affect the microleakage in self-etch mode.

Short-Term Comparison of Clinical Performance of Universal Adhesives with Self-Etch Mode in NCCL Restorations.

OBJECTIVES: To evaluate the clinical performance of universal adhesives with self-etch mode regarding their functional monomer and HEMA contents. METHODS: The study involved 27 patients (108 restorations) aged between 34 and 69 (mean age: 53.8). Each restoration contained one of four different universal adhesives applied in self-etch mode: G-Premio Bond (HEMA-free, MDP and 4-MET containing), Xeno Select (HEMA and MDP-free), Tetric-n-Bond Universal (HEMA and MDP-containing) and Clearfil Universal Bond Quick (HEMA, MDP and amide monomers containing). The restorations were evaluated according to the FDI criteria at baseline, 6, and 12 months. The data were statistically analyzed using Friedman's and Kruskal-Wallis tests for significance in each pair (p⟨0.05). RESULTS: After 12 months, one restoration was lost in each of the G-Premio Bond and Clearfil Bond Quick groups. The success rate was 96.3% for both adhesives and 100% for Xeno Select and Tetric-n-Bond adhesives. There was no statistically significant difference between the four dentin adhesive groups among all the evaluation periods regarding any evaluation criteria. However, four universal adhesives showed clinically acceptable marginal discoloration and marginal deterioration in a few restorations. CONCLUSION: Monomer contents of universal adhesives with self-etch mode had no significant effect on the success of restorations.

Effect of different types of adhesive systems on the bond strength and marginal integrity of composite restorations in cavities prepared with the erbium laser-a systematic review.

There are inconclusive results regarding etching and bonding protocol to achieve optimal bond strength and marginal integrity of adhesive composite resin restorations in erbium laser prepared cavities. This systematic review aimed to consider which adhesive system protocol may be optimal in achieving the bond strength and marginal integrity in erbium laser-prepared cavities, comparable to that obtained with conventional method of cavity preparation. This review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with literature search based on all publications during the period January1, 2000-October 10, 2020, in three databases: MEDLINE, Google Scholar and ScienceDirect. The necessary information was extracted by two independent authors. The search resulted in 139 articles from all databases, and a total of thirty-one articles met the inclusion criteria. The results indicated that the selection of adhesives depending on their pH and composition and the laser pulse duration and pulse energy used plays an important role in predicting the adhesion and marginal integrity. The 10-MDP containing moderate self-etch adhesives has demonstrated predictable outcomes. Longer pulse durations used for cavity preparations may indicate the use of etch-and-rinse (EnR) or moderate self-etch adhesives (SEA) to allow better resin infiltration in deep craters formed due to laser irradiation. However, further studies with more standardizations in relation to adhesives and laser parameters are needed.

Delayed light activation of resin composite affects the bond strength of adhesives under dynamic simulated pulpal pressure.

OBJECTIVE: To evaluate the effect of a time delay before the light activation of resin composite on the microtensile bond strength (µTBS) of self-etch adhesives under dynamic simulated pulpal pressure. MATERIALS AND METHODS: One hundred twenty crown segments were prepared from human third molars. Dentin surfaces were prepared with coarse diamond burs and connected to a dynamic pulpal pressure device. The self-etch adhesives used were Clearfil SE Bond (CSE), G2-Bond Universal (G2B), Clearfil Universal Bond Quick (CBQ), and G-Premio Bond (GPB). Each adhesive was divided into 3 subgroups: immediate light activation of resin composite (T0), delayed light activation for 150 s (T1), and 300 s (T2). The µTBS data were obtained after 24-h water storage. Scanning electron microscopy was used to evaluate the nanoleakage at the resin-dentin surface. The µTBS data were analyzed using two-way ANOVA and Duncan's multiple comparisons. RESULTS: All adhesives demonstrated a significant reduction in µTBS at T2, except for CBQ where the bond strength was not affected by the delayed light activation times. The two-step self-etch adhesives (CSE and G2B) demonstrated higher bond strength than the one-step adhesives at all conditions. Nanoleakage was observed in all adhesives at T2; however, nanoleakage was detected only in CBQ and GPB at T1. CONCLUSIONS: Delayed light activation of resin composite adversely affected the dentin bond strength of self-etch adhesives. Two-step self-etch adhesives had better bonding performance than one-step self-etch adhesives. CLINICAL RELEVANCE: After adhesive application, resin composite should be adapted and cured as soon as possible.

Eight-year clinical evaluation of two types of resin composite in non-carious cervical lesions.

OBJECTIVES: In this clinical study, the 8-year clinical performances of a flowable resin composite was compared with that of a conventional resin composite. MATERIALS AND METHODS: Ninety non-carious cervical lesions (NCCLs) in 19 participants were involved in this trial. NCCLs were restored with a flowable composite (Clearfil Flow FX: FX, Kuraray Noritake, Japan) or a conventional resin composite (Clearfil AP-X: AP) in conjunction with a one-step self-etch adhesive (Clearfil S3 Bond). Each participant had both types of resin composite restorations that were randomly allocated. The restorations were evaluated at baseline and annually up to 8 years using modified USPHS criteria. The data were statistically analyzed using the Fisher's exact test, Kaplan-Meier method, and a multivariate Cox-regression with frailty models (p < 0.05). RESULTS: The 8-year participant recall rate was 95%. One hundred percent retention was recorded for AP, whereas four out of 46 restorations were lost for FX during the 8 years. The incidence of marginal staining increased over time regardless of the type of resin composite, showing 48% for AP and 57% for FX after 8 years. Wear of the resin composite occurred only for the flowable material and there was a significant difference between the types of resin composite (p = 0.024). Overall survival rates at 8 years for AP and FX were 98% and 82% respectively (p = 0.110). CONCLUSIONS: The flowable resin composite presented lower wear resistance and showed a lower survival rate compared with the conventional composite after eight years of clinical service. CLINICAL RELEVANCE: Flowable resin composites may show greater wear after long-term clinical service. TRIAL REGISTRATION NUMBER: UMIN000028745, Date of registration: August 19, 2017.