Assessment of Bond Strength between Metal Brackets and Non-Glazed Ceramic in Different Surface Treatment Methods

Objective: The aim of this study was to evaluate the bond strength between metal brackets and non-glazed ceramic with three different surface treatment methods.Materials and Methods: Forty-two non-glazed ceramic disks were assigned into three groups. Group I and II specimens were etched with 9.5% hydrofluoric acid. Subsequently in group I, silane and adhesive were applied and in group II, bonding agent was used only.In group III, specimens were treated with 35% phosphoric acid and then silane and adhesive were applied. Brackets were bonded with light-cured composites. The specimens were stored in water in room temperature for 24 hours and then thermocycled 500 times between 5°C and 55°C.Results: The difference of tensile bond strength between groups I and III was not significant(P=0.999). However, the tensile bond strength of group II was significantly lower than groups I, and III (P<0.001). The adhesive remnant index scores between the threegroups had statistically significant differences (P<0.001).Conclusion: With the application of scotch bond multi-purpose plus adhesive, we can use phosphoric acid instead of hydrofluoric acid for bonding brackets to non-glazed ceramic restorations

Treatment of a Rare Bilateral Sever Ectopic Eruption of the Maxillary First Permanent Molar: A Case Report

A 7.5 year-old girl was seeking orthodontic treatment because of severe ectopic eruption of maxillary first permanent molars. It was a rare case that represented approximately horizontal view in panoramic radiograph. The severity of problem was high, but since thepatient had maxillary deficiency, it was important to perform the treatment without extraction.Treatment began with extraction of upper deciduous second molars and continued with a modified Nance appliance. The period of treatment was 16 months and the resultwas excellent. This satisfactory outcome of treatment justifies clinicians to evaluate and diagnose this group of problems and start treatment as soon as possible to achieve acceptable results

Tensile Bond Strength of Metal Bracket Bonding to Glazed Ceramic Surfaces With Different Surface Conditionings

Objective: The objective of this study was to compare the tensile bond strength of metal brackets bonding to glazed ceramic surfaces using three various surface treatments.Materials and Methods: Forty two glazed ceramic disks were assigned to three groups. In the first and second groups the specimens were etched with 9.5% hydrofluoric acid (HFA). Subsequently in first group, ceramic primer and adhesive were applied, but in second group a bonding agent alone was used. In third group, specimens were treated with 35% phosphoric acid followed by ceramic primerand adhesive application. Brackets were bonded with light cure composites. The specimens were stored in distilled water in the room temperature for 24 hours and thermocycled 500 times between 5°C and 55°C. The universal testing machine was used to test the tensile bond strength and the adhesive remenant index scores between three groups was evaluated. The data were subjected to one-way ANOVA, Tukey and Kruskal-Wallis tests respectively.Results: The tensile bond strength was 3.69±0.52 MPa forfirst group, 2.69±0.91 MPa for second group and 3.60±0.41 MPa for third group. Group II specimens showed tensile strength values significantly different from other groups (P<0.01).Conclusion: In spite of limitations in laboratory studies it may be concluded that in application of Scotch bond multipurpose plus adhesive, phosphoric acid can be used instead of HFA for bonding brackets to the glazed ceramic restorations with enough tensile bond strength