Effects of Ozone and Prophylactic Antimicrobial Applications on Shear Bond Strength of Orthodontic Brackets.

OBJECTIVE: The present study aimed to evaluate the effects of ozone and prophylactic antimicrobial applications on the shear bond strengths and bond failure interfaces of orthodontic brackets. METHODS: Sixty human canine teeth were randomly divided into three groups (n=20), receiving the following treatments: Group I-pumice prophylaxis (Isler Dental, Ankara, Turkey)+37% orthophosphoric acid (Dentsply, Rio de Janeiro, Brazil)+Transbond XT primer and adhesive (3M Unitek, Monrovia, USA); Group II-prophylaxis paste (Topex, NJ, USA)+37% orthophosphoric acid (Dentsply, Rio de Janeiro, Brazil)+ Transbond XT primer and adhesive paste (3M Unitek, Monrovia, USA); and Group III-ozone application (Biozonix GmbH, Munich, Germany)+37% orthophosphoric acid (Dentsply, Rio de Janeiro, Brazil)+Transbond XT primer and adhesive (3M Unitek, Monrovia, USA). All specimens were stored at 37°C water for 24 h. Shear bond strength was assessed using a universal testing device (Autograph AGS-X; Shimadzu, Japan). Adhesive remnant index (ARI) scores were obtained through examination of teeth under stereomicroscope at 10× magnification after debonding. RESULTS: Shear bond strengths of orthodontic brackets were 16.10, 18.01, and 19.23 MPa for Groups I, II, and III, respectively. No statistically significant difference in shear bond strength of orthodontic brackets was found among the groups (p=0.273), based on Kruskal-Wallis analysis. Additionally, no significant difference was found in the ARI scores of each group using chi-square analysis (p=0.992). CONCLUSION: Shear bond strength of orthodontic brackets and ARI scores was not found to be negatively impacted by ozone application.

Micro-shear bond strength of adhesive resins to enamel at different relative humidity conditions.

This study tested whether exhaled humid conditions would affect the adhesion of etch-and-rinse, two-step and one-step self-etch adhesive resins to enamel. Enamel surfaces of human maxillary anterior teeth (N=240, n=20) were exposed to four humid conditions (H1: 63-68%, H2: 73-78%, H3: 93-98%, H4: 36-45% RH) during bonding with Adper Single Bond 2 (SB2), Clearfil SE Bond (CSE) and Adper Easy Bond (AEB). Specimens were stored in distilled water at 37 ºC for 24 h and tested to failure using micro-shear bond strength (µSBS) test. Data were analyzed using two-way ANOVA and Tukey's test (p<0.05). The µSBS to enamel with SB2, CSE and AEB was not significantly affected by humidity parameters. AEB resulted in significantly lower µSBS in all conditions. The frequency of adhesive failures was the highest at H2, H3 for SB2, H3 for CSE and H1-4 for AEB indicating that humidity conditions may decrease adhesion quality to enamel.

Influence of powdered dentin on the shear bond strength of dentin bonding systems.

This study evaluated the effect of different amounts of dentin powder (DP) mixed in Clearfil SE Bond (CSB) or Single Bond (SB) on adhesion to dentin. Human third molars (n=96) were sectioned to expose the mid-coronal dentin and divided into eight experimental groups (n=12 per group), namely, Group 1: CSB, Group 2: CSB+1.5 mg DP, Group 3: CSB+3 mg DP, Group 4: CSB+4.5 mg DP, Group 5: SB, Group 6: SB+1.5 mg DP, Group 7: SB+3 mg DP, and Group 8: SB+4.5 mg DP. Filtek Z250 composite was bonded onto dentin, and all specimens were subjected to shear bond strength test at a crosshead speed of 1 mm/min. Highest bond strength was obtained in Groups 1, 2, and 3 (15.1, 13.5, and 16.4 MPa respectively; p>0.05) and the lowest in Groups 6, 7, and 8 (5.5, 5.6, 4 MPa; p>0.05). DP addition, regardless of amount, adversely affected the bond strength of SB. Bond strength of CSB was not affected when 1.5 or 3 mg of DP was added.

An alternative adhesive strategy to optimize bonding to root dentin.

INTRODUCTION: This study examined the hypothesis that the shear-bond strengths of AH Plus (AH) and Hybrid Root Seal (HRS) to root dentin might be optimized by using a powdered dentin-reinforced bonding procedure. METHODS: The surfaces of root halves obtained from extracted human premolars were ground (800-grit silicon carbide paper), treated (5.25% NaOCl 17% EDTA for 5 minutes followed by distilled water) and randomly allocated into two groups according to the sealer and then into three subgroups according to bonding procedure. Dentin particles with a maximum size of 25 µm were incorporated into the adhesive of Clearfil Liner Bond 2V, and groups were created as follows: no adhesive, adhesive alone, and with powdered dentin reinforced adhesive; 3 × 3 mm high buildups were created using sealer and allowed to set (37 °C, 100% humidity, 72 hours). Shear tests were performed (1 mm/min). Data were calculated as MPa and analyzed (two-way analysis of variance, Tukey test). RESULTS: A significant difference was found between the groups (P = .000). Adhesive or reinforced adhesive had a negative effect on the shear-bond strength of AH, but they significantly increased the shear-bond strength of HRS (P = .000). HRS showed a similar bond strength with either adhesive alone or adhesive reinforced with powdered dentin. AH group was characterized by mixed failure, whereas the predominant failure type of the HRS group was cohesive failure within the sealer. CONCLUSIONS: Reinforcing adhesive resin with powdered dentin may be considered an alternative for optimizing the bonding of methacrylate-based sealers to root dentin and might affect the shear bond strength.

The effect of loading on microTBS of four all-in-one adhesives on bonding to dentin.

This in vitro study analyzed the effect of mechanical loading on microtensile bond strength (microTBS) to dentin of four all-in-one adhesives and compared with a total-etch adhesive system. The tested adhesives were Danville Experimental (an unfilled single-component adhesive containing a proprietary organophosphate and hydrophobic monomers; Danville Materials), G Bond (GC), Clearfil S(3) Bond (Kuraray), AdheSE One (Vivadent), and Prelude Total-Etch (Danville Materials). Dentin surfaces were exposed and composite resin (AP-X, Kuraray) build-ups were created. The samples were divided into two subgroups and the first subgroups were subjected to mechanical fatigue loading (5 x 10(4); 50 Nat 0.2 Hz). Testing was performed after 1 week using a "nontrimming" microTBS test at a cross head speed of 1 mm/min. The data was calculated as MPa and statistically analyzed using Multivariate Analysis of Variance. Multiple comparisons were done using t-test. Mechanical loading significantly decreased microTBS of the tested materials (p = 0.000). Prelude Total-etch showed the highest bond strength values when compared to the tested all-in-one adhesives (p < 0.01). G Bond and Clearfil S(3) Bond showed significantly higher bond strength values than Danville Experimental and AdheSE One (p < 0.01).