The effect of desensitizing treatments on the bond strength of resin composite to dentin mediated by a self-etching primer

Clinical Efficacy of Two Different Desensitizers in Reducing Postoperative Sensitivity Following Composite Restorations

Objective: The objective is to evaluate the efficacy of different desensitizing agents in the reduction of postoperative sensitivity after composite restoration.

Materials and methods: Class I cavities were prepared in 39 patients by the same operator. The patients included in the study were between 20 and 45 years with vital pulp and a remaining dentin thickness of 1mm. Previously restored, nonvital and tooth with periodical changes were excluded. Patients were randomly assigned into three groups of 13 each - Group I (Control); Group II (Gluma desensitizer) and Group III (shield active desensitizer [SAD]). After the surface treatment, the teeth were restored with composite. The patients were assessed for postoperative sensitivity at 24 hours and one week with a visual analog scale (VAS).

Statistical Analysis: Data were analyzed using SPSS v23 software. Data were analyzed using one-way ANOVA and post-hoc Tukey test.

Results: Gluma and SAD on comparison with control group i.e. composite group showed statistical significance difference at day 1 (P-value 0.003), but on comparing the sensitivity after one week, there is no significant difference in sensitivity score between all three groups (P-value 0.073). There was no statistically significant difference between day 1 and one week when comparing Gluma desensitizer and SAD.

Conclusion: The application of the desensitizer led to a statistically significant reduction in postoperative sensitivity on day 1 and a clinically significant reduction was observed at one week.

Influence of Diode Laser for the Treatment of Dentin Hypersensitivity on Microleakage of Cervical Restorations

Noncarious cervical lesions (NCCLs) are a common clinical finding often linked with dentin hypersensitivity (DH). Aim. The aim of the study was to evaluate the influence of diode laser for the treatment of DH on microleakage of subsequent NCCL restorations. Materials and Methods. Forty-eight extracted human premolars were collected. All teeth received standardized cervical preparation on both the buccal and palatal surfaces and were randomly divided into three groups (n = 16) according to the restorative material used: nanohybrid composite resin (CR), resin-modified glass ionomer (RMGI), and conventional glass ionomer (GIC). The prepared cavities on the palatal surfaces were treated by diode laser using SIROlaser Blue (Sirona Dental Systems, Bensheim, Germany) prior to restoration, while preparations on the buccal surfaces were directly restored. After thermocycling, the teeth were immersed in methylene blue dye for microleakage evaluation under 40x magnification at both occlusal and cervical margins. The Kruskal-Wallis test followed by the Bonferroni tests was conducted to determine inter- and intragroup differences (P < 0.05). Results. All restorative materials tested showed some degree of microleakage with no statistically significantly different scores with or without the use of laser desensitization prior to restorative treatment. Group CR showed the least microleakage, followed by group RMGI, while group GIC showed the highest. Cervical margins showed greater microleakage than the occlusal margins where the difference was statistically significant in the RMGI group without laser pretreatment (P = 0.006) and in both groups CR (P = 0.02) and RMGI (P = 0.006) with the laser pretreatment. Conclusion. Application of diode laser for the treatment of DH prior to the restoration of teeth with NCCL did not affect the microleakage of all the restorative materials tested. All the materials showed some degree of microleakage, which was higher in gingival margins compared to occlusal margins. The resin composite shows the least microleakage among all the tested materials.

Influences of desensitizing agents on bond strength of etch-and-rinse and self-etch adhesive system to dentin

Background:

Cervical lesions requiring adhesive restoration may present with dentin hypersensitivity, but the effect of desensitizer treatment on microtensile bond strength (MBS) is inconclusive.

Aim:

The aim of the present study was to assess the influence of two types of dentin desensitizing treatment on bond strength to dentin.

Materials and Methods:

Thirty-six extracted human mandibular first premolars were used to obtain superficial buccal cervical dentin. The samples were assigned to two groups (18/group): etch-and-rinse (ERS) (Optibond^® Solo) and self-etch (Palfique) adhesive systems. Eighteen teeth in each group were randomly assigned to three desensitizer treatments (6/treatment); control (no desensitization), Gluma™ desensitizerand Novamin-containing toothpaste (Sensodyne repair and protect™). Bonded dentin-composite specimens were stored in artificial saliva for 2 weeks prior to scanning electron microscope (SEM) evaluation and MBS testing. Univariate analysis of variance and Tukey tests were performed (α = 0.05) for the data analysis.

Results:

The mean MBS with self-etch system (SES) was significantly higher than ERS system, irrespective of the dentin desensitizer regimen. SEM showed no hybrid layer or resin tag formation in the SES group. Tubular occlusion was observed in all specimens treated with desensitizer.

Conclusion:

Mild self-etch adhesive can be used on dentin treated with Gluma or bioglass-containing desensitizer without compromising the bond strength.

Clinical Relevance:

Dentin desensitizer such as in-office Gluma or at-home Novamin-containing toothpaste could be used without compromising the bond strength of mild self-etch adhesive systems.

Influence of desensitizing agents in management of noncarious cervical lesion and bonded restorations: A preliminary 12-week report

OBJECTIVES

The primary objective of this study was to investigate the effectiveness in reducing dentin hypersensitivity in noncarious cervical lesions (NCCLs) by home-based desensitizing toothpaste (TP), in-office Gluma desensitizer application, and resin-modified glass-ionomer cement (RMGIC) restoration. The secondary objective was to evaluate the long-term outcome of the glass-ionomer cement restoration following the application of bioactive glass-containing desensitizer TP.

MATERIALS AND METHODS

A total of 73 patients or 151 teeth were included in the study and randomly allotted to one of the four different treatment groups. Pre- and postoperative symptom and air-blast/tactile sensitivity scores were recorded for statistical analysis. Postoperative sensitivity was analyzed at 1, 4, and 12 weeks after treatment. Nonparametric statistical tests were employed.

RESULTS

Kruskal-Wallis test noted a significant reduction in postoperative sensitivity at all time periods with the RMGIC group compared to other treatment options. Significantly higher patient dropout was observed in desensitizing TP regimen.

CONCLUSIONS

This interim 12-week report on dentin hypersensitivity management of NCCLs concludes that resin-modified glass-ionomer restoration was able to achieve a significant instant reduction in sensitivity and patient satisfaction compared to other noninvasive at-home and in-office procedures.

CLINICAL RELEVANCE

This interim 12-week report on dentin hypersensitivity management of noncarious cervical lesions concludes that resin-modified glass-ionomer restoration was able to achieve a significant reduction in sensitivity, and patient satisfaction was higher compared to other noninvasive at-home and in-office procedures.

Effect of desensitizing agents on the microtensile bond strength of two-step etch-and-rinse adhesives to dentin

Desensitizers can be used to control postoperative sensitivity in adhesive restorations. The aim of this study was to evaluate the effect of desensitizing agents on the bond strength of two-step etch-and-rinse adhesive systems to dentin. Forty-two human molars were sectioned to obtain 3-mm-thick dentin discs. The discs were divided into three groups (n = 14 in each) - no-treatment control group (CT), and oxalic acid [BisBlock (BB)] and calcium phosphate [Desensibilize Nano-P (NP)] desensitizers - before the application of two adhesive systems [Adper Single Bond Plus (SB) and One-Step Plus (OSP)]. A nanoparticle composite resin was used to create a 3-mm-thick build-up. The specimens were stored in distilled water for 24 h before a microtensile bond-strength test was performed. The failure modes were determined using a stereomicroscope at 100 × magnification. Specimens were sectioned perpendicular to the interface for scanning electron microscopy analyses. The CT-SB group exhibited the highest bond strength, differing significantly from BB-SB and BB-OSP groups. Mixed failures were prevalent for all groups. Scanning electron microscopy revealed a continuous hybrid layer and resin tags in all groups. Dentin bond strength of etch-and-rinse adhesive systems was reduced by an oxalic acid desensitizer but was not affected by a calcium phosphate-containing desensitizer.

Toothpaste prevents debonded brackets on erosive enamel

This study evaluated the effect of high fluoride dentifrice on the bond strength of brackets after erosive challenge. Eighty-four enamel specimens were divided into seven groups (n = 12): WN (distilled water/no acid challenge), W3C (distilled water/3 cycles of acid challenge), and W6C (distilled water/6 cycles of acid challenge) were not submitted to dentifrice treatment. Groups RF3C (regular fluoride dentifrice/3 cycles of acid challenge) and RF6C (regular fluoride dentifrice/6 cycles of acid challenge) were treated with dentifrices containing 1450 μg F⁻/g and HF3C (high fluoride dentifrice/3 cycles of acid challenge) and HF6C (high fluoride dentifrice/6 cycles of acid challenge) were with 5000 μg F⁻/g. Acid challenges were performed for seven days. After bond strength test, there was no significant difference among groups submitted to 3 cycles of acid challenge (P > 0.05). Statistically significant difference was found between the regular and high fluoride dentifrices after 6 cycles of acid challenge (<0.05). Similar areas of adhesive remaining were found among control groups and among groups W6C, RF3C, RF6C, HF3C, and HF6C. The high fluoride dentifrice was able to prevent the reduction of bond strength values of brackets submitted to acid challenge. Clinical relevance: the high fluoride toothpaste prevents debonded brackets on erosive enamel.

The effect of dentin desensitizers and Nd:YAG laser pre-treatment on microtensile bond strength of self-adhesive resin cement to dentin

PURPOSE

The purpose of this study is to evaluate if pre-treatment with desensitizers have a negative effect on microtensile bond strength before cementing a restoration using recently introduced self-adhesive resin cement to dentin.

MATERIALS AND METHODS

Thirty-five human molars' occlusal surfaces were ground to expose dentin; and were randomly grouped as (n=5); 1) Gluma-(Glutaraldehyde/HEMA) 2) Aqua-Prep F-(Fluoride), 3) Bisblock-(Oxalate), 4) Cervitec Plus-(Clorhexidine), 5) Smart protect-(Triclosan), 6) Nd:YAG laser, 7) No treatment (control). After applying the selected agent, RelyX U200 self-adhesive resin cement was used to bond composite resin blocks to dentin. All groups were subjected to thermocycling for 1000 cycles between 5-55℃. Each bonded specimen was sectioned to microbars (6 mm × 1 mm × 1 mm) (n=20). Specimens were submitted to microtensile bond strength test at a crosshead speed of 0.5 mm/min. Kolmogorov-Smirnov, Levene's test, Kruskal-Wallis One-way Analysis of Variance, and Conover's nonparametric statistical analysis were used (P<.05).

RESULTS

Gluma, Smart Protect and Nd:YAG laser treatments showed comparable microtensile bond strengths compared with the control group (P>.05). The microtensile bond strengths of Aqua-Prep F, and Cervitec Plus were similar to each other but significantly lower than the control group (P<.05). Bisblock showed the lowest microtensile bond strength among all groups (P<.001). Most groups showed adhesive failure.

CONCLUSION

Within the limitation of this study, it is not recommended to use Aqua-prep F, Cervitec Plus and Bisblock on dentin when used with a self-adhesive resin cement due to the decrease they cause in bond strength. Beside, pre-treatment of dentin with Gluma, Smart protect, and Nd:YAG laser do not have a negative effect.