Shear bond strength of ceramic laminate veneers to finishing surfaces with different percentages of preserved enamel under a digital guided method

Background

The purpose of this in vitro study was to evaluate the effect of the percentages of preserved enamel on ceramic laminate veneers’ (CLVs) shear bond strength (SBS).

Methods

Seventy extracted human maxillary central incisors were scanned and reconstructed into three-dimensional models. The extracted teeth were then embedded and randomly divided into seven groups (n = 10 per group). Based on digital analyses of the three-dimensional models, guided tooth preparation and bonding procedures were performed individually to form seven different percentages (100%, 80%, 60% 50%, 40%, 20% and 0%) of remaining enamel thickness on the bonding surface. Finally, the SBS test was performed, and the data were statistically analysed by one-way ANOVA with LSD post hoc test (α = 0.05).

Results

The complete enamel surface exhibited the highest SBS (19.93 ± 4.55 MPa), followed by 80% enamel (19.03 ± 3.66 MPa), 60% enamel (18.44 ± 3.65 MPa), 50% enamel (18.18 ± 3.41 MPa), 40% enamel (17.83 ± 3.01 MPa) and 20% enamel (11.32 ± 3.42 MPa) group. The lowest SBS (9.63 ± 3.46 MPa) was detected in 0% enamel group. No significant difference was observed among the 40–100% enamel groups, while the 20% or 0% enamel group demonstrated a significantly lower mean SBS than the 40% enamel group (p < 0.05).

Conclusion

The SBS value of CLVs bonded to 100% enamel on the finishing surfaces (nearly 20 MPa) was twice that which bonded to 0% enamel (nearly 10 MPa). Bonding to 100% enamel is the most reliable treatment. When dentin exposure is inevitable, enamel should be preserved as much as possible to maintain good bonding. In addition, 40% of preserved enamel on the bonding surface was the minimal acceptable value to fulfil the requirements of good bonding strength.

Bond strength of conventional versus modified methods for Class IV restorations in primary incisors: An in vitro study

Background. Aesthetic restorations of severely decayed anterior primary teeth are challenging due to the small size of the teeth and the large pulp chambers. Therefore, this study evaluated and compared the tensile and shear bond strengths of conventional versus modified methods (slot technique) of Cl IV restorations in primary incisors. Methods. A total of 120 extracted intact maxillary primary central and lateral incisors were divided into two groups. In group A, conventional Cl IV cavities were prepared. In group B, after conventional cavity preparation, four and three incisal slots were prepared on the incisal edges of the central and lateral incisors, respectively. All the teeth were restored using composite resin, and then the tensile and shear bond strengths were evaluated. Results. A statistically significant increase in the tensile bond strength of restorations was recorded in the modified technique compared to the conventional method (P=0.001). Although an increase in the shear bond strengths was found in the modified method, the value did not reach a statistically significant level (P=0.158). The most frequent fracture type was adhesive in the conventional group and cohesive in the modified group, considering the tensile and shear bond strength tests. In both groups, the highest average tensile bond strength was recorded in teeth with the cohesive fracture in dentin, and the lowest average was seen in the adhesive type. Conclusions. Incisal slots could increase the tensile bond strengths of Cl IV composite resin restorations in primary teeth.

Shear bond strength after using sealant before bonding: a systematic review and meta-analysis of in vitro studies

OBJECTIVES

Decalcification during orthodontic treatment is significantly increased. To prevent this negative impact, new treatments with sealants before bonding brackets are commonly been used. This systematic review discusses current knowledge on shear bond strength when using sealant before bonding.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed to identify studies that address shear bond strength after using a sealant before bonding brackets. The search was carried out using common electronic databases in addition to individual searches. Both screening and study eligibility analysis were performed according to PRISMA and Cochrane Guidelines for systematic reviews. Several terms describing shear bond strength after using a sealant before bonding brackets were searched. Particular attention was paid to bond failure and bracket loss. For the statistical outcome, all results were shown in a forest plot based on standardized mean differences (SMD) with a random-effects model to respect heterogeneity of these studies. To assess the heterogeneity of the different trials, I2-value and the Q-Test were performed.

RESULTS

The initial search identified 416 studies. After a thorough selection process, a total of 15 articles met the inclusion criteria. All 15 articles reported results of in vitro studies. Papers were divided into four subgroups according to their used product: ProSeal, Transbond bonding, the combination of Transbond bonding and ProSeal and Clearfil Protect Bond. The results of this review demonstrate a high heterogeneity of the studies. The SMD of the examined 15 articles show nearly no difference between the control and the intervention groups in shear bond strength (p < 0.0001; OR - 0.12; Cl - 0.47-0.23). Forest plots for comparison of the subgroups depict no difference in shear bond strength as well.

CONCLUSIONS

This meta-analysis concludes that there is no additive benefit for shear bond strength when using sealant before bonding. However, additional randomized controlled studies should be performed to analyze impact of sealants on bonding strength and bracket loss in more detail.

CLINICAL RELEVANCE

Using sealants before orthodontic bonding does not reduce shear bond strength.

Evaluation the properties of orthodontic adhesive incorporated with nano-hydroxyapatite particles

Objective

This research was designed to study the effects of calcium hydroxyapatite nanoparticle incorporation on polymerization as well as the shear bond strength for Heliosit adhesive.

Materials and methods

Calcium hydroxyapatite nanoparticles were prepared from natural products using the sol-gel method, and were inspected using a transmission electron microscope. The nanoparticles were added to the conventional orthodontic adhesive at 2% wt and 4% wt concentrations. The degree of conversion for each test group was measured using a Fourier transform infrared spectroscopy device. Each adhesive group was used for bonding metal brackets to the premolar buccal enamel surface. The shear bond strength of all samples was measured.

Results

A significant difference was found among all the study groups (p ≤ 0.05) in terms of the degree of conversion and shear bond strength. The 2% wt nanoparticle group showed the highest values for both variables. The lowest value was recorded within the 4% wt nanoparticle group in comparison to the control group.

Conclusions

Calcium hydroxyapatite nanoparticle incorporation with a conventional Heliosit adhesive resin to a limited concentration has improved the mechanical properties of orthodontic adhesive.

Effect of Saliva Contamination on Shear Bond Strength of Self-etch Adhesive System to Dentin: An In Vitro Study

Aim and objective

This study aimed to evaluate the outcome of saliva contamination on shear bond strength (SBS) of a self-etch adhesive system to dentin.

Materials and methods

A total of 60 premolars were selected. Occlusal surfaces of the teeth were severed off. Three groups of 20 teeth in each were formed after the samples were randomly divided. Group I: Not subjected to any contamination (control group). Group II: Contamination with saliva occurred before coating the teeth with a self-etch adhesive system. Group III: Contamination with saliva occurred after coating the teeth with a self-etch adhesive system. After the contamination, the composite was placed with the help of a Teflon tube. Under the universal testing machine, the SBS of these samples was then tested.

Results

The data obtained after testing were analyzed using SPSS software. Statistical difference was seen between all the three groups. Group II projected the least SBS.

Conclusion

Contamination with saliva has a deleterious effect on the SBS. Contamination that occurs before the application of adhesive systems has shown considerably reduced SBS.

Clinical significance

This study successfully established that saliva contamination acts as a major factor in reducing the SBS of the bonding agent. Hence, in clinical situations, it is necessary to ensure sufficient steps are taken to eliminate or reduce the chances of contamination with saliva to aid in the success of the restoration.

How to cite this article

Chaudhari RR, Srivastava HR, Raisingani D, et al. Effect of Saliva Contamination on Shear Bond Strength of Self-etch Adhesive System to Dentin: An In Vitro Study. Int J Clin Pediatr Dent 2021;14(4):443–446.

Orthodontic bonding to silicate ceramics: impact of different pretreatment methods on shear bond strength between ceramic restorations and ceramic brackets

Objective

The study aims to investigate the shear bond strength (SBS) between silicate ceramic restorations and ceramic brackets after different pretreatments and aging methods.

Material and methods

Leucite (LEU) and lithium disilicate (LiSi) specimens were pretreated with (i) 4% hydrofluoric acid + silane (HF), (ii) Monobond Etch&Prime (MEP), (iii) silicatization + silane (CoJet), and (iv) SiC grinder + silane (SiC). Molars etched (phosphoric acid) and conditioned acted as comparison group. SBS was measured after 24 h (distilled water, 37 °C), 500 × thermocycling (5/55 °C), and 90 days (distilled water, 37 °C). Data was analyzed using Shapiro–Wilk, Kruskal–Wallis with Dunn’s post hoc test and Bonferroni correction, Mann–Whitney U, and Chi² test (p < 0.05). The adhesive remnant index (ARI) was determined.

Results

LEU pretreated with MEP showed lower SBS than pretreated with HF, CoJet, or SiC. LiSi pretreated with MEP resulted in lower initial SBS than pretreated with HF or SiC. After thermocycling, pretreatment using MEP led to lower SBS than with CoJet. Within LiSi group, after 90 days, the pretreatment using SiC resulted in lowest SBS values. After HF and MEP pretreatment, LEU showed lower initial SBS than LiSi. After 90 days of water storage, within specimens pretreated using CoJet or SiC showed LEU higher SBS than LiSi. Enamel presented higher or comparable SBS values to LEU and LiSi. With exception of MEP pretreatment, ARI 3 was predominantly observed, regardless the substrate, pretreatment, and aging level.

Conclusions

MEP pretreatment presented the lowest SBS values, regardless the silicate ceramic and aging level. Further research is necessary.

Clinical relevance

There is no need for intraoral application of HF for orthodontic treatment.

Comparative evaluation of mechanical and physical properties of a new bulk-fill alkasite with conventional restorative materials

PURPOSE

The physical and mechanical performance of a newly commercialized dental restorative material (alkasite) was compared with glass ionomer cement (GIC) and nano-hybrid composite.

METHODOLOGY

Human extracted premolars were used to investigate the shear bond strength. Restorative materials were placed on the dentine surface and were aged in deionized water for 14 days. The 3-D surface roughness was evaluated before and after chewing simulation cycles (50,000). The samples were fatigued mechanically using a chewing simulator and investigated with a scanning electron microscope (SEM).

RESULTS

For shear bond strength, alkasite showed significantly high values than GIC, whereas non-significant difference was observed between alkasite and nano-hybrid composite. After the chewing simulation (50,000 cycles), non-significant difference was found between GIC and nano-hybrid composite, where surface roughness values were highest for GIC and lowest for alkasite.

CONCLUSION

The newly developed restorative material (alkasite) has shown better results than existing restorative materials.

Effect of Direct versus Indirect Bonding Technique on the Failure Rate of Mandibular Fixed Retainer-A Systematic Review and Meta-Analysis

INTRODUCTION

Fixed retainer failure is a common cause of relapse and may require additional orthodontic treatment. The two main methods for bonding the mandibular fixed retainer include direct and indirect techniques. This topic has not been explored previously in a systematic review. Therefore, the objective of this systematic review was to evaluate the effect of direct versus indirect bonding technique on the failure rate of mandibular fixed retainer.

METHODS

Online databases (PubMed, Dental and Oral Science, CINAHL, and Cochrane Central Register of Controlled Trials, Scopus) were systematically searched electronically for articles up until April 2021. Google Scholar and clinicaltrials.gov databases were utilized for hand searching. Randomized, non-randomized clinical trials and cohort studies on human subjects were considered regardless of language or year of publication. Orthodontic patients in their retention phase (mandibular 3×3 fixed retainer), in which the retainer was bonded using direct bonding technique as control and indirect as intervention were included. The outcome assessed was retainer failure rate. Two authors independently examined and extracted the data from the studies that satisfied the inclusion criteria. Risk of bias in clinical trials was assessed using the Cochrane Collaboration's tool, whereas risk of bias in cohort studies was assessed using the Newcastle-Ottawa Scale. The meta-analysis was conducted using the RevMan software V.5.3.5.22. The outcome was estimated using weighted average difference and 95% confidence intervals (CIs). The studies' heterogeneity was assessed using Cochrane's heterogeneity test (I2 Test).

RESULTS

Four articles fulfilling the inclusion criteria were included in qualitative and quantitative synthesis. Retainer failure rates were analysed in a total number of 266 patients bonded with mandibular 3×3 retainers after orthodontic therapy. Direct bonding technique of fixed retainer on 131 patients was compared with indirect technique on 135 patients. There was no statistically significant difference in the rate of retainer failure between the two methods (95% CI, 0.67, 1.40).

CONCLUSIONS

Within the limitations of insufficient evidence this systematic review and meta-analysis concluded that there is no difference in the failure rate of mandibular fixed retainers between direct and indirect bonding techniques. Due to the scarcity of available data, further studies are needed to establish definitively one's clinical benefit over the other.

Comparison of feldspathic veneer surface treatments on ceramic bracket SBS, ARI and surface roughness after different debonding/polishing methods: An in vitro study

OBJECTIVES

To analyse, in vitro, surface properties and the shear bond strength after debonding and polishing procedures of ceramic brackets directly bonded to 0.3-0.5-mm thick feldspathic veneers.

MATERIALS AND METHODS

Fifty six feldspathic ceramic veneers samples (0.3 to 0.5-mm thick) were allocated into groups according to veneers surface treatment procedures: (S) glaze layer was retained; (SHF) hydrofluoric (HF) acid etch; (SOXA) Al2O3 sandblasting; and (SB) diamond burs roughening. Specimens were treated with silane Monobond N® and ceramic brackets bonded with Transbond XT^®. Shear bonding strength (SBS) was assessed with a universal testing machine and ARI evaluated under a stereomicroscopic coupled to a digital camera. Remaining bonding composite was removed using a porcelain polishing kit and surface roughness assessed with a stylus profilometer.

RESULTS

No statistically significant differences were identified for SBS among the study groups (S, SHF, SOXA and SB) (P>0.05). The majority of the specimens presented ARI scores 3 and 2 (P>0.05). All of the study groups presented increased surface roughness after debonding and polishing procedures (P<0.05), with significant greater values observed in SB group (RaF: 1.27±0.41; RzF: 6.23±1.82), (P<0.05).

CONCLUSIONS

Surface treatment with hydrofluoric acid etch, Al₂O₃ sandblasting and diamond bur did not enhance SBS of orthodontic brackets bonded to ceramic veneers. Ceramic surfaces treated with diamond burs presented significantly increased roughness after adhesive removal.

Effect of surface treatments and flash-free adhesive on the shear bond strength of ceramic orthodontic brackets to CAD/CAM provisional materials

OBJECTIVES

To evaluate the effect of surface treatments and flash-free adhesive on the shear bond strength of ceramic orthodontic brackets bonded to materials used for the fabrication of CAD/CAM provisional crowns.

MATERIALS AND METHODS

Specimens (n = 160) from each provisional material (CAD-Temp and C-Temp) were categorized into four groups according to the surface treatment methods: C (no surface treatment), HP (37% H₃PO₄), DB (mechanical roughening by diamond bur), and SB (mechanical roughening by blasting). Maxillary central incisor ceramic brackets (Clarity™ Advanced ceramic brackets, 3 M Unitek) were bonded to the conditioned provisional materials according to the used adhesive system (n = 20), APC PLUS or APC flash-free. All specimens were evaluated for shear bond strength testing (SBS) and the adhesive remnant index (ARI). Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests.

RESULTS

C-Temp significantly recorded higher SBS than CAD-Temp (24.0 and 16.0 MPa, respectively) (p < 0.001). DB and SB groups utilizing flash-free adhesive significantly recorded higher SBS (18.2 and 24.0 MPa, respectively) (P < 0.05) compared to other groups in the tested materials. Higher ARI scores were recorded in CAD-Temp and flash-free adhesive.

CONCLUSIONS

Mechanical surface treatments and flash-free adhesive would enhance SBS of ceramic orthodontic brackets to CAD/CAM provisional materials. The higher ARI scores reported with CAD-Temp and flash-free adhesive reduce chair time for excess removal.

CLINICAL RELEVANCE

Bonding of orthodontic brackets to provisional restorations is a challenge for orthodontists in adult comprehensive cases that could be improved by an appropriate provisional material, surface treatments, and adhesive system.

Effect of using different component combinations for orthodontic bracket bonding with self-etch primers

PURPOSE

To evaluate bonding quality for orthodontic bracket bonding with different component combinations of self-etch primers in vitro.

METHODS

Metallic brackets were bonded to bovine lower incisors and assigned to groups. Group 1: comparison of self-etch (Transbond™ Plus, 3M™ Unitek, Neuss, Germany, n = 30; BrackFix® primer SE, VOCO®, Cuxhaven, Germany, n = 20) and etch-and-rinse bonding systems (Transbond™ XT, n = 20; BrackFix®, n = 20); group 2: comparison of different self-etch primer (Transbond™ Plus; BrackFix® primer SE) and adhesive (Transbond™ XT, n = 20; BrackFix®, n = 20) product combinations; group 3: testing cyclic fatigue bond strength of self-etch bonding systems (Transbond™ Plus, n = 20; BrackFix® primer SE, n = 20). All teeth were tested for shear bond strength according to the DIN-13990 standard, the adhesive remnant index (ARI) and enamel fractures were determined microscopically (10 × magnification).

RESULTS

The mean shear bond strength of the self-etch (Transbond™ Plus: 16.38 ± 3.68 MPa; BrackFix® primer SE: 16.24 ± 1.73 MPa) and etch-and-rinse bonding systems (Transbond™ XT: 18.45 ± 2.56 MPa; BrackFix®: 17 ± 5.2 MPa) were of a clinically adequate order of magnitude (≥ 6-10 MPa) and were not statistically different. The component combination BrackFix® primer SE/Transbond™ XT adhesive led to a significantly lower shear bond strength (11.99 ± 3.68 MPa). There were no significant differences between static and fatigue shear bond strengths of self-etch bonding systems. Mean ARI scores mostly ranged between 4 and 5. The combination of the self-etch primer Transbond™ Plus with the BrackFix® adhesive led to a significantly increased enamel fracture rate.

CONCLUSIONS

Based on the present findings bond strength of self-etch primers was equal to etch-and-rinse primers for bracket bonding. Combining different self-etch bonding systems might alter the clinical performance.

Bonding ability of resin cements to different types of CAD/CAM composite blocks

This study investigated the bonding performance of two different types of resin cements to computer-aided design/computer-aided manufacturing (CAD/CAM) composite blocks based on the shear bond strength (SBS) test. A silane-containing self-adhesive resin cement (Panavia SA Cement Universal) and resin luting cement (Block HC Cem) with a primer, were used. Specimens were fabricated from three different types of CAD/CAM composite blocks, and their surfaces were blasted with alumina. Resin cements were bonded to the specimens, and their SBSs were measured after 15 min, 24 h, and after being subjected to thermal cycling for 10,000 and 30,000 cycles. Three-way ANOVA for bond strength revealed that CAD/CAM composite block, resin cement and storage time significantly influenced the SBS values, and the three-way interactions between the evaluated factors, and all the interactions were significant. It was concluded that the bonding performance of resin cements to CAD/CAM composite blocks were material and storage period dependent.

Effect of adhesive application method on repair bond strength of composite

Objectives

This study aimed to evaluate the effect of the application method of universal adhesives on the shear bond strength (SBS) of repaired composites, applied with different thicknesses.

Materials and Methods

The 84 specimens (Filtek Z350 XT) were prepared, stored in distilled water for a week and thermocycled (5,000 cycles, 5°C to 55°C). They were roughened using 400-grit sandpapers and etched with phosphoric acid. Then, specimens were equally divided into 2 groups; Single Bond Universal (SU) and Prime&Bond Universal (PB). Each group was subdivided into 3 subgroups according to application methods (n = 14); UC: 1 coat + uncuring, 1C: 1 coat + curing, 3C: 3 coats + curing. After storage of the repaired composite for 24 hours, specimens were subjected to the SBS test and the data were statistically analyzed by 2-way analysis of variance and independent t-tests. Specimens were examined with a stereomicroscope to analyze fracture mode and a scanning electron microscope to observe the interface.

Results

Adhesive material was a significant factor (p = 0.001). Bond strengths with SU were higher than PB. The highest strength was obtained from the 1C group with SU. Bonding in multiple layers increased adhesive thicknesses, but there was no significant difference in SBS values (p = 0.255). Failure mode was predominantly cohesive in old composites.

Conclusions

The application of an adequate bonding system plays an important role in repairing composite resin. SU showed higher SBS than PB and the additional layers increased the adhesive thickness without affecting SBS.

Photodynamic therapy and other pretreatment methods on epoxy-based glass fiber post on the push-out bond strength to radicular dentin

AIM

To assess the push-out bond strength (PBS) of glass fiber post (GFP) conditioned using different surface treatment regimens bonded to radicular dentin MATERIAL AND METHODS: Sixty central incisors and canine were collected and disinfected. Decoronation following working length was determined using K-file. Rotary file system was used for cleaning and shaping. Canals of all samples were dried with paper points and obturated with gutta percha. Canal space was prepared with peso reamers. Now samples were randomly allocated into six groups based on pretreatment of GFP. Post in group 1 treated with 9% HFA+ Silane, post in group 2 surface treated with silane only, Post in group 3 surface treated with airborne particle (50 µm), group 4 post conditioned with photodynamic therapy (PDT), group 5 post pretreatment was performed with MBP and in group 6 GFP was not treated. Conditioned and non-conditioned posts were positioned in canal space and cemented. Tooth were sectioned coronally, middle and apically. Sections were positioned in universal testing machine (UTM) and debonded surfaces were evaluated for failure modes. The means and standard deviations of PBS were examined using one-way analysis of variance (ANOVA).

RESULTS

Coronal third of group 3 in which posts were sandblasted using airborne Al₂O₃ particle presented the highest PBS (11.21±0.64 MPa). Whereas, an apical section of group 4 in which posts were treated with PDT exhibited the lowest bond integrity.

CONCLUSION

Sandblasting using airborne particles (50 µm) and hydrogen peroxide (H₃PO₄) conditioned with GFP exhibited significantly higher bond strength as compared to the control. However, PDT decreases the PBS of fiber post with the root dentin.

Influence of methylthioninium chloride, curcumin and Er, Cr: YSGG on caries affected dentin bonded to bioactive and conventional bulk fill dental restorative material

AIM

The study aimed to determine the influence of Er, Cr: YSGG (ECL), methylene blue photosensitizer (MBP), and curcumin photosensitizer (CP) disinfection on CAD and its bond strength and microleakage to bioactive (BA) and multicore (MC) bulk-fill composite.

MATERIALS AND METHODS

Sixty carious mandibular molars were collected based on the criteria of ICDAS Code 6 (International Caries Detection and Assessment system). Specimens were embedded in polyvinyl pipes up to CEJ and subjected to preparation of standard class II cavity leaving CAD in situ for bonding. All samples were randomly assigned to eight groups based on disinfection regimes and type of bulk-fill material. Samples in group 5 and 6 didn't undergo any disinfection; group 1: ECL + BA, group 2: ECL+ MC; group 3 MBP + BA, group 4: MBP + MC; group 5: Conventional Etch and Rinse + BA (Control), group 6 Conventional Etch and Rinse + MC (Control); group 7: CP +BA and group 8 CP+MC. Specimens were tested for SBS using a universal testing machine and the debonded surfaces were evaluated under a stereomicroscope to determine modes of failure. A dye penetration test was performed for microleakage assessment. For intergroup comparison test analysis of variance (ANOVA) was performed using means and standard deviation from each group. Tukey HSD was used for multiple group comparison tests. The level of significance was established at p < 0.05.

RESULTS

The maximum mean bond strength was shown by group 6 (18.96 ± 0.31 MPa) conventional etch and rinse+ MC (control). Whereas, the minimum SBS was recorded in specimens of group 7 CP +BA (13.04 ± 0.81 MPa). SBS values among group 3 (14.05 ± 0.10 MPa- MBP+BA), group 4 (13.66 ± 0.39- MBP+MC) group 7 (13.04 ± 0.81 MPa- CP +BA and group 8 (14.21 ± 0.59 MPa- CP+MC) were found to be comparable (p>0.05). There was no statistically significant difference among the study groups concerning microleakage (p >0.05).

CONCLUSION

CAD treated with ECL for the adhesive bonding of BA and conventional bulk-fill composite MC has shown potential to be used clinically. Moreover, MBP and CP for conditioning of CAD need further investigation.

Bond assessment of enamel conditioned with Er, Cr: YSGG laser and methylene blue photosensitizer activated by photodynamic therapy to orthodontic metallic brackets

AIM

To assess bond integrity and failure mode after enamel pretreated with conventional and contemporary conditioning methods were bonded to metallic brackets (MB).

MATERIAL AND METHODS

Forty maxillary central incisors were selected and disinfected. All specimens were mounted up to the cement-o-enamel junction and divided into four experimental groups randomly based on the enamel conditioning technique. Photodynamic therapy (PDT) was used to condition enamel in group 1, Total-etch and rinse (TER) was used to treat samples in group 2, Specimens in group 3 were conditioned with ECL, and samples in group 4 surface pretreated with SEP. Bonding of MB was performed on the surfaces of all the specimens with a Transbond XT. Specimens from all investigated groups were positioned on a universal testing machine maintaining buccal surfaces similar to the direction of the force. After bracket debonding bond failure was assessed using ARI. The bond integrity of all four groups was compared using analysis of variance (ANOVA). Post hoc Tukey test was used for pairwise comparison among different groups.

RESULTS

Group 2, TER+MB (15.38±0.14 MPa) displayed the highest bond value whereas the lowest values of SBS were exhibited by group 1, PDT+MB (10.11±0.17 MPa). The inter-group comparison revealed that specimens of group 2 and group 3, ECL+MB (14.61±0.55 MPa) demonstrated comparable bond strength (p>0.05).

CONCLUSION

Enamel conditioned with TER and ECL demonstrated comparable SBS. However, bond integrity after PDT and SEP (self-etch primer) surface treatment of enamel bonded with MB significantly lowered bond values.

Evaluation of Shear Peel Bond Strength of Different Adhesive Cements Used for Fixed Space Maintainer Cementation: An In Vitro Study

Aim and objective

This study aims to compare the retentive strength of different adhesive cements used for band cementation of fixed space maintainer by comparing the shear peel bond strength and mode of failure for each adhesive material using three different adhesive cements.

Materials and methods

Eighty intact extracted teeth were used to assess the shear peel bond strength. Preformed bands were adapted to each tooth. Three cements compared in this in vitro study are glass ionomer cement [Ketac Cem radiopaque (3M ESPE)], resin-modified glass ionomer cement [RelyX luting 2(3M ESPE)], and self-adhesive resin cement [RelyX U200 (3M ESPE)]. The teeth were randomly divided to four groups of 20 samples each. All samples were stored at 37°C for 24 hours before testing. All specimens were tested in a tensile mode using a universal testing machine to determine shear peel bond. After debonding procedure, each specimen was visually assessed at the site of cement.

Results

The results of our study showed that the greatest resistance to decementation was shown by self-adhesive resin cement (256.85 N) followed by resin-modified GIC (165.40 N) and GIC (127.40 N) (p < 0.001). Self-adhesive resin cement has the greatest shear peel bond strength (2.36 MPa) followed by resin-modified GIC (1.53 MPa), conventional GIC (1.22 MPa), and bands without cementation (0.29 MPa) (p < 0.001). In terms of adhesive remnant index (ARI) scores, it was seen that the decementation of bands of both conventional GIC and self-adhesive resin cements occurred at the band/enamel interface. However, resin-modified GIC showed varied results in the ARI scores.

Conclusion

The findings of our study suggest that self-adhesive resin cements can be used for cementation of bands of fixed space maintainers. However, further research with short-term and long-term data is required to evaluate the ability of these cements for its application in vivo.

How to cite this article

Kaur J, Singh A, Sadana G, et al. Evaluation of Shear Peel Bond Strength of Different Adhesive Cements Used for Fixed Space Maintainer Cementation: An In Vitro Study. Int J Clin Pediatr Dent 2021;14(2):175-179.

No-primer adhesive vs. self-adhesive resin: bonding strength following LED curing

PURPOSE

The goal of this study was to compare the shear bond strength (SBS) and failure modes of three different adhesive resins following the use of two different dental curing light units.

METHODS

A total of 160 human premolars were randomly divided into four groups (N = 40 for each): group 1, Transbond™ XT (3M Unitek, Monrovia, CA, USA) adhesive paste; group 2, Heliosit Orthodontic paste with no primer; group 3, Maxcem Elite (Kerr, Orange, CA, USA) self-adhesive resin with prior etching; group 4, Maxcem Elite self-adhesive resin with no etching. Each group was further divided into 2 subgroups: half (named "a") were cured with VALO LED (Ultradent Products, South Jordan, UT, USA), and the other half (named "b") with the Elipar LED unit (3M Unitek LED, Monrovia, CA, USA). The brackets were submitted to SBS testing 24 h after bonding. Adhesive Remnant Index (ARI) scores and bonding time were also measured. Two-way analysis of variance (ANOVA) and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

No significant differences in SBS were observed when comparing the two different LED devices within the same bonding material. The mean SBS of group 1 was significantly higher compared to groups 2, 3, and 4 (p < 0.001). Mean SBS values of groups 2 and 3 were significantly higher than that of group 4 (p < 0.001). ARI scores were significantly different in groups 4a and 4b compared to the other groups (p < 0.05). Group 4a showed significantly lower bonding time/tooth compared to the other groups except to groups 3a and 4b (p < 0.001).

CONCLUSIONS

Decreasing curing time using high-power LED device did not significantly affect SBS. However, the composite type did affect SBS.

Using self-etch adhesive agents with pit and fissure sealants. In vitro analysis of shear bond strength, adhesive remnant index and enamel etching patterns

Purpose

The aim of this study was to evaluate in vitro, the shear bond strength (SBS) and adhesive remnant index (ARI) of pit and fissure sealants (PFS) after enamel conditioning with different new-generation self-etching (SE) agents; additionally, enamel etching patterns were assessed.

Methods

Healthy unerupted third molars surgically removed for therapeutic reasons (n = 25p/g), were randomly assigned to six groups. Conventional etching (CE) or SE was applied prior to pit and fissure sealants bonding. Enamel conditioned surfaces were evaluated by SEM at × 500, × 1000, and × 2000 magnification to determine etching patterns. Subsequently, 25 PFS blocks (3 × 2 × 1.5 mm) p/g were bonded to enamel surface.

Samples were stored in water at 37 °C for 24 h, previous to SBS and ARI test. One-way ANOVA and Tamhane statistic tests were used for SBS; while Mann–Whitney U and Kruskal–Wallis were employed for ARI (p ≤ 0.05).

Results

For SBS test, CE_PFS_3M and SE1_PFS_Shofu groups showed the lowest values (8.74 ± 4.02 and 8.75 ± 3.90, respectively). The highest scores were observed in SE_PFS_Kuraray group (13.46 ± 5.83). Significant differences in SBS and ARI assessments were found. All experimental groups showed type 1 etching pattern.

Conclusion

The etching pattern was less pronounced in self-etching groups, which showed an equal or superior in vitro performance compared to conventional etching agents. The clinical use of self-etching agents could be recommended before pit and fissure sealants application in new dental protocols. The best in vitro performance was observed when both applied materials, self-etching agent and pit and fissure sealant have 10-methacryloyloxydecyl dihydrogen phosphate in their chemical composition.

The effect of diabetes mellitus on the shear bond strength of composite resin to dentin and enamel

Diabetes mellitus might be linked to the deterioration of certain physical properties of dentin and enamel. This study aimed to determine the effect of two types of diabetes on the shear bond strength of enamel and dentin, by using the single bond universal bonding system. Sixty specimens [from 15 teeth; 5 from each group-non-diabetic (ND), Diabetic type I (D1), and Diabetic type II (D2)], were prepared with equal amounts of dentin (n = 5) and enamel (n = 5). Enamel specimens (E20) were etched with 37% phosphoric acid, for 20 s, and dentin specimens (D15) were etched for 15 s. A standard shear bond strength test was performed on all specimens. Their failure modes were also studied under a scanning electron microscope, and the data were analyzed by using ANOVA and Post Hoc Tukey's test (a = 0.050). For the enamel groups, significant differences were only noticed between the ND and D1 (P < 0.050) groups, and between the ND and D2 (P < 0.050) groups. In the dentin groups, there was a significant difference only between the ND and D1 (P < 0.050) groups. The micrographs showed that the ND group had the highest number of specimens with cohesive failure and D1 had the highest number of specimens with adhesive failure. It can be concluded that both types of diabetes reduce the shear bond strength of composite resin on dentin and enamel. However, it seems that the negative effect of diabetes on shear bond strength of dental composite resin is more drastic in individuals with type I diabetes as compared with type II.

Effects of customized resin base on bonding strength of spherical self-ligating brackets

PURPOSE

Fabricating resin bases has become an easy and economical method to achieve the customization of brackets. This study aimed to assess the effect of the resin base on bonding strength of spherical self-ligating brackets.

METHODS

A defined amount of adhesive was bonded to the bracket base and constituted the new resin base. The thickness of the adhesive was measured and controlled at 0.5, 1.0, 1.5 and 2.0 mm, and a group without a resin base was used as a control. Sixty extracted human premolars were randomly divided into five groups. The brackets in each group were bonded to the specimen, and debonding tests were conducted. The shear bond strength (SBS) was calculated according to the measured debonding force in relation to the base area. The adhesive remnant index (ARI) score and the residual location of the fractured resin base were recorded. Enamel damage was also analyzed by scanning electron microscopy. After assessing for data normality and homogeneity, statistical comparisons between the groups and correlations among parameters were determined. P < 0.05 was regarded as significant.

RESULTS

The correlation analysis revealed an inverse correlation between the resin base thickness and the SBS (Coeff = -0.719, P < 0.01). The highest SBS was 9.33 MPa, in the control group, which was significantly greater than the lowest SBS (6.03 MPa), in the 2.0-mm group (P < 0.05). Multiple comparisons analysis revealed no differences in SBS between the 1.0-, 1.5- and 2.0-mm groups. Nonparametric analysis found that only the ARI score in the 0.5-mm group (2.92) was significantly different (P < 0.05) from that in the control group (1.25). As the thickness of the resin base increased, the fractured resin base tended to remain at the bracket base, and the risk of enamel damage decreased.

CONCLUSIONS

As the thickness of the resin base increased, the bonding strength of the spherical bracket decreased. However, the required clinical bonding strength was still satisfied when the thickness was less than 2.0 mm. The existence of a resin base could protect the enamel surface from damage caused by debonding. The customization of spherical brackets by tailoring a resin base can be applied in clinical practice because of the clinically acceptable bonding strength.

Physical and chemical mechanisms involved in adhesion of orthodontic bonding composites: in vitro evaluations

Background

Bond strength of orthodontic composite is strongly influenced by molecular and structural mechanisms. Aim of this in vitro study was to compare bond strength of light-cure orthodontic composites by measuring debonding forces and evaluating locations of bond failure. Investigations on chemical compositions clarified adhesive behaviors and abilities, exploring effects of ageing processes in this junction materials.

Methods

Twelve enamel discs, from human premolars, were randomly coupled to one orthodontic adhesive system (Transbond XT™ 3 M UNITEK, USA, Light-Cure Orthodontic Paste, LEONE, Italy and Bisco Ortho Bracket Paste LC, BISCO, Illinois) and underwent to Shear Bond Strength test. Metallic brackets were bonded to twenty-seven human premolar, with one of the adhesive systems, to quantify, at FE-SEM magnifications, after debonding, the residual material on enamel and bracket base surfaces. Raman Spectroscopy analysis was performed on eight discs of each composites to investigate on chemical compositions, before and after accelerated aging procedures in human saliva and sugary drink.

Results

Orthodontic adhesive systems showed similar strength of adhesion to enamel. The breakage of adhesive-adherent bond occurs in TXT at enamel-adhesive interface while in Bisco and Leone at adhesive-bracket interface. Accelerated in vitro aging demonstrated good physical–chemical stability for all composites, Bisco only, was weakly contaminated with respect to the other materials.

Conclusion

A similar, clinically adequate and acceptable bond strength to enamel for debonding maneuvers was recorded in all orthodontic adhesive systems under examination. No significant chemical alterations are recorded, even in highly critical situations, not altering the initial mechanical properties of materials.

Effect of sandblasting and/or priming treatment on the shear bond strength of self-adhesive resin cement to CAD/CAM blocks

The aim of this study was to investigate the effect of two different priming agents and/or sandblasting on the shear bond strength of self-adhesive resin cement to the resin composite for core build-up to CAD/CAM blocks. A CAD/CAM ceramic block (GN I CERAMIC BLOCK, GC) and a CAD/CAM resin composite block (CERASMART 270, GC), a self-adhesive resin cement (G-CEM ONE, GC) and two different primers, i.e., a multipurpose primer (MP; G-Multi Primer, GC) and a ceramic primer (CP; Ceramic Primer II, GC), were examined. Five different surface treatments with priming and/or sandblasting and no surface treatment (control) were performed on the block. Disk specimens (6 mm in diameter and 4 mm in thickness) made from core composites were cemented to the blocks after the surface treatments. Then, the 24-h shear bond strength of the resin cement between the block and the resin composite core was determined (n = 15). Sandblasted specimens had greater bond strength than controls for both blocks (p < 0.05). Priming to both blocks significantly increased the bond strength of resin cement compared to that of controls (p < 0.05). Although Weibull moduli were not significantly changed among all surface treatments for both blocks, the strengths with 5% and 95% failure probability of sandblasted and/or primed blocks were estimated to be greater than those of controls. The combination of priming and sandblasting to the CAD/CAM composite and ceramic surface was effective in increasing the bond strength of the resin cement.

Shear Bond Strength of Different MDP-Containing Adhesive Systems on Enamel and Dentin from Primary Teeth

OBJECTIVE

To compare the shear bond strength (SBS) after thermocycling of four universal adhesives applied in self-etch mode on dentin and etch-and-rinse mode on enamel.

STUDY DESIGN

Flat 144 buccal or lingual dentin and enamel surfaces from 72 non-carious primary molars were prepared. Samples were segregated into 12 groups (n=12): Adper Single Bond 2 etch-and-rinse (SB_T) and Clearfil SE Bond self-etch (SE_S) applied to enamel and dentin served as controls. Scotch Bond Universal Adhesive (SBU), Clearfil S3 Bond Universal Adhesive (SEU), Tetric N-Bond Universal Adhesive (TEN), and All Bond Universal (BIS) were applied in etch-and-rinse mode to enamel and in self-etch mode to dentin. They were thermocycled for 5000 cycles. SBS testing and the evaluation of fracture mode were performed.

RESULTS

SB_T showed statistically higher SBS than other adhesive groups using etch-and-rinse mode on enamel. SE_S and BIS had statistically higher SBS than other adhesive groups using self-etch mode on dentin. Mixed failure was the most common failure mode in each group.

CONCLUSION

The universal adhesives did not show higher SBS than SB_T when using etch-and-rinse on enamel. All universal adhesives showed higher SBS than SB_T and had SBS similar to SE_S, except SBU when using self-etch mode on dentin.

Effect of Bonding Agent on Retention of Different Sealants: An in Vitro Study

OBJECTIVES

To investigate the effect of Co-curing versus Staged-curing and No-bonding on retention of different resin-based sealants (RBS).

STUDY DESIGN

For shear bond strength (SBS) and microleakage tests, 90 extracted premolars were divided equally into 3 groups (I, II, III). Each group was further subdivided equally into 3 subgroups (a, b, c). No-bonding subgroups did not receive a bonding agent, Staged-curing subgroups received a bonding agent that was cured before sealant application, while Co-curing subgroups received a bonding agent that was cured after sealant application. Seal-it was applied for group I, Helioseal-F for group II and Clinpro for group III. SBS buttons were tested using Instron machine, while microleakage specimens were examined using micro-CT.

RESULTS

Clinpro showed the highest SBS values in Staged-curing and No-bonding groups (8.72±2.39, 12.51±3.16) respectively. Staged-curing was significantly greater in SBS values than those for other groups (P<0.05). There was a significant difference in microleakage values of Staged-curing among different RBS (P = 0.003), while there was no significant difference in values of No-bonding and Co-curing among different RBS (P = 0.541, P = 0.521).

CONCLUSIONS

The use of a bonding agent as Staged-curing was more effective in improving sealant retention than No-bonding and Co-curing.