Effects of different universal adhesives and surface treatments on repair bond strength between resin composites

OBJECTIVE

This study aimed to evaluate the effects of different universal adhesives and surface treatments on the repair bond strength between resin composites.

MATERIALS AND METHODS

A total of 220 composite samples were divided into three groups according to the adhesive resin to be applied: 1) Scotchbond Universal, 2) G-Premio Bond, and 3) Peak Universal Bond. They were then divided into seven subgroups according to surface treatments (n = 10): A) air abrasion, B) air abrasion+silane, C) hydrofluoric acid, D) hydrofluoric acid+silane, E) air abrasion+hydrofluoric acid+silane, F) silane, and G) no surface treatment (negative control). After surface treatment, a repair composite was applied. Samples aged in the thermocycle were subjected to micro-tensile bond strength testing. Cohesive strength values of 10 non-aged composite blocks were used as a positive control. Kruskal-Wallis and one-way ANOVA tests were used for statistical evaluation. Fractured surfaces were evaluated using a scanning electron microscope.

RESULTS

In Scotchbond Universal and G-Premio Bond, the mean micro-tensile bond strength value of the no surface treatment subgroup was significantly lower than that of the positive control. All subgroups of Peak Universal Bond showed similar values to the positive control.

CONCLUSION

While Scotchbond Universal and G-Premio Bond required mechanical roughening before adhesive application, Peak Universal Bond did not require any surface treatment.

CLINICAL SIGNIFICANCE

Different universal adhesives may show different repair bonding strengths with different surface treatments. Since achieving a standard in this regard can be associated with many independent factors, clinicians should determine how to apply the adhesive they use most effectively with the most appropriate surface treatment based on their own clinical experience.

Effect of Aging on Surface Roughness and Color Stability of a Novel Alkasite in Comparison with Current Direct Restorative Materials

AIM

To compare the surface roughness and color stability of a novel alkasite with current direct restorative materials with and without an aging step.

METHODS AND MATERIALS

Twenty-six specimens of each of the following materials were prepared: alkasite, ormocer, giomer, high-viscosity glass ionomer, glass carbomer, and nanohybrid composite (control). Half of the specimens in each group were stained, the other half of the specimens were aged and then stained. Color and surface roughness evaluations were conducted at baseline, after aging and after staining, using a dental spectrophotometer, and a three-dimentional (3D) noncontact optical profilometer, respectively. Statistical analyses were completed using one-way analysis of variance, post hoc Tukey test, and paired samples t-test.

RESULTS

At baseline and after aging, the surface of alkasite was found to be rougher than nanohybrid composite and ormocer surfaces (p<0.05). However, in terms of roughness increase caused by aging, ormocer, nanohybrid composite, and alkasite were affected in a similar way (p>0.05). In terms of color stability, alkasite was more colored than nanohybrid composite and ormocer (p<0.05), and performed similar to giomer (p>0.05).

CONCLUSIONS

The surface roughness and color stability characteristics of alkasite material was between composite resins and glass ionomer-based materials after aging.

Effect of different dry-polishing regimens on the intrapulpal temperature assessed with pulpal blood microcirculation model

OBJECTIVE

The aim of the study was to evaluate the effect of different dry-polishing regimens on the intrapulpal temperature assessed using a pulpal blood microcirculation model.

MATERIALS AND METHODS

Eighty extracted human mandibular premolar teeth were used. Standardized class V cavity preparations were performed and were then restored. Teeth were divided into four main groups (n = 20): Fine polishing disc (SSF; 3M Sof-Lex, 3M ESPE, Minnesota); Super-fine polishing disc (SSS; 3M Sof-Lex); Spiral finishing wheel (SSW; 3M Sof-Lex); Enhance PoGo-One step diamond micro-polisher cup (EPO; Dentsply Sirona, Inc, Delaware). The main groups were divided: the low-load pressure (0.4N) and the high-load pressure (0.8N). The average change in intrachamber temperatures (Δt), from initial to highest, were measured.

RESULTS

The highest temperature increase was recorded in SSF08 (9.55°C). The lowest value was recorded in EPO04 (1.9°C). SSS08, SSW08, and EPO08 demonstrated significantly higher Δt values than the low-load mode in SSS04, SSW04, and EPO04, respectively (P < .0001).

CONCLUSIONS

Temperature was the least affected by the diamond cup in both pressure modes, and it was also less affected by the spiral finishing wheel in the low-load mode than in the high-load mode. Fine and super-fine discs had the greatest effect on intrachamber temperatures.

CLINICAL SIGNIFICANCE

The present study suggests intrachamber temperature can rise among different dry-polishing regimes. Dental practitioners should pay attention to dry-polishing regimens and pressures for reducing heat-related dental problems.

Effect of resin infiltration and microabrasion on the microhardness, surface roughness and morphology of incipient carious lesions

OBJECTIVE

The effects of resin infiltration and microabrasion on incipient carious lesions by surface microhardness, roughness and morphological assessments, and resistance to further acid attack of treated lesions were evaluated.

MATERIAL AND METHODS

Eighty artificially-induced incipient lesions were randomly divided into five groups (n = 16): resin infiltration with an adhesive resin (Excite F, Ivoclar Vivadent, Schaan, Liechtenstein), resin infiltration with a resin infiltrant (Icon, DMG, Hamburg, Germany), microabrasion without polishing (Opalustre, Ultradent, South Jordan, UT, USA), microabrasion with polishing (Opalustre, Ultradent, Diamond Excel, FGM, Joinville, SC, Brazil), and distilled water (control group). All specimens were exposed to demineralization for another 10 d. Microhardness, roughness and morphological assessments were done at baseline, following initial demineralization, treatment and further demineralization. Data were analysed by the Kruskal-Wallis, Friedman's and Bonferroni tests (p < .05).

RESULTS

Enamel lesions treated with resin infiltrant and microabrasion demonstrated similar hardness values, with a nonsignificant difference compared with sound enamel. Resin infiltration demonstrated lower roughness values than those of microabrasion, and the values did not reach the values of sound enamel. Further demineralization for 10 d did not affect the hardness but increased the roughness of infiltrated and microabraded enamel surfaces. Polishing did not influence the roughness of microabraded enamel surfaces. After resin infiltration, porosities on enamel were sealed completely. The surface structure was similar to that of the enamel conditioning pattern for microabraded enamel lesions.

CONCLUSIONS

Within the limitations of this study, the icon infiltration and microabrasion technique appeared to be effective for improving microhardness. Icon appeared to provide reduced roughness, although not equal to sound enamel. Further research is needed to elucidate their clinical relevance.

Effect of tooth discolouration severity on the efficacy and colour stability of two different trayless at-home bleaching systems

Background. The use of trayless at-home bleaching agents in darker teeth is raising some concerns due to their unknown efficacy. The purpose of this in vitro study was to evaluate the effect of tooth discolouration severity on the efficacy and colour stability of two different trayless at-home bleaching systems.

Methods. Ninety enamel-dentin samples were divided into two groups: lighter tand darker teeth. The teeth in each group were further divided into three groups (n=15): (1) tray-based system with 10% carbamide peroxide (Opalescence Oh) (control group); (2) a tray applied whitening membrane with 10% hydrogen peroxide (Treswhite Supreme); and (3) a whitening pen with 22% carbamide peroxide (Hollywood Smiles). After bleaching, the teeth were stained for 9 days using red wine. Colour readings before bleaching treatment were determined using a dental spectrophotometer and were repeated 24 h after bleaching treatment and 24 h after staining process. Analysis of variance, Bonferroni and Dunnett C tests were used at 5% significance level.

Results. No differences were observed between the bleaching efficacy of Treswhite Supreme and Opalescence Oh in the lighter teeth, while Opalescence Oh had the best bleaching efficacy in the darker teeth (p<0.05). Hollywood Smiles had the worst bleaching efficay but the best color stability in both lighter and darker teeth (p<0.05). No differences were observed between the color stability values of Treswhite Supreme and Opalescence Oh.

Conclusion. This study suggested that both the tooth discolouration severity and the type of trayless system used affected the bleaching efficacy, whereas only the type of trayless system affected the color stability.

Clinical performance of a combined approach for the esthetic management of fluorosed teeth: Three-year results

OBJECTIVE

The long-term clinical performance of combined therapy including enamel microabrasion and vital bleaching is debatable due to the abrasion of outer enamel surface. The aim of this longitudinal cohort study was to evaluate the 3-year clinical performance of enamel microabrasion in combination with vital tooth bleaching for the esthetic management of fluorosed teeth.

MATERIALS AND METHODS

Fifteen patients with 176 fluorosed incisors and canines were included in this study. All the teeth were treated with enamel microabrasion (Opalustre, Ultradent), and at-home bleaching technique (10% Opalescence PF, Ultradent). Fluorosed teeth were evaluated at baseline, after microabrasion, after combined therapy, and at 3-year follow-up in terms of esthetic criteria (esthetic appearance, brown stains, and opaque white areas), side effects, and patient satisfaction using visual analog scales. The data were statistically analyzed (α = 0.05).

RESULTS

Fluorosed teeth revealed significantly better esthetic appearance after microabrasion and combined therapy and at 3-year follow-up compared to those at baseline (P P Conclusions: The combined therapy was effective in the esthetic management of fluorosed teeth. However, a significant relapse was observed in the esthetic appearance and brown stains of these patients after 3 years, which also reduced patient satisfaction.

Comparison of enamel microabrasion with a combined approach to the esthetic management of fluorosed teeth

OBJECTIVE

To compare in vivo the efficacy of enamel microabrasion alone or in combination with vital tooth bleaching for the management of tooth discoloration caused by fluorosis.

METHODS

A total of 118 maxillary and mandibular fluorosed incisors and canines in 10 patients, scored from 1 to 7 according to the Tooth Surface Index of Fluorosis, were included in this study. All of the teeth were initially treated with enamel microabrasion (Opalustre, Ultradent Products Inc, South Jordan, UT, USA), and after 24 hours, an in-office bleaching technique (Opalescence Boost, Ultradent) was utilized (n=118). Standardized images of the teeth were taken using a digital camera prior to treatment and 24 hours after the enamel microabrasion and after the in-office bleaching therapy. The study groups were assigned according to evaluation time: a) after enamel microabrasion (Group 1) and b) after the combined approach (enamel microabrasion and in-office bleaching) (Group 2). Two calibrated and blinded examiners scored Group 1 and Group 2 images by comparing each with baseline images for "improvement in appearance," "changes in brown stains," and "changes in white opaque areas" using the visual analogue scales (VAS) that range from 1 to 7. "Patient satisfaction," "tooth sensitivity," and "gingival problems" were also recorded. The data were analyzed using two sample paired Wilcoxon signed-rank, Kruskal-Wallis, and Mann-Whitney U-tests (α=0.05).

RESULTS

The combined therapy revealed significantly higher scores than the enamel microabrasion procedure in terms of all of the evaluated criteria (p<0.001). Enamel microabrasion provoked less tooth sensitivity but led to lower patient satisfaction scores than the combined therapy (p<0.001); however, in terms of gingival problems, no differences were found between both groups.

CONCLUSION

The combined therapy, including enamel microabrasion and in-office bleaching, was more effective than enamel microabrasion alone in the esthetic management of fluorosed teeth.