Effect of Four Methods of Surface Treatment on Shear Bond Strength of Orthodontic Brackets to Zirconium.

OBJECTIVES: Providing reliable attachment between bracket base and zirconia surface is a prerequisite for exertion of orthodontic force. The purpose of the present study was to evaluate the effect of four zirconium surface treatment methods on shear bond strength (SBS) of orthodontic brackets. MATERIALS AND METHODS: One block of zirconium was trimmed into four zirconium surfaces, which served as our four study groups and each had 18 metal brackets bonded to them. Once the glazed layer was removed, the first group was etched with 9.6% hydrofluoric acid (HF), and the remaining three groups were prepared by means of sandblasting and 1W, and 2W Er: YAG laser, respectively. After application of silane, central incisor brackets were bonded to the zirconium surfaces. The SBS values were measured by a Dartec testing machine with a crosshead speed of 1 mm/min. Data were analyzed using one-way ANOVA and Tukey's HSD for multiple comparisons. RESULTS: The highest SBS was achieved in the sandblasted group (7.81±1.02 MPa) followed in a descending order by 2W laser group (6.95±0.87 MPa), 1W laser group (6.87±0.92 MPa) and HF acid etched group (5.84±0.78 MPa). The differences between the study groups were statistically significant except between the laser groups (P<0.05). CONCLUSION: In terms of higher bond strength and safety, sandblasting and Er: YAG laser irradiation with power output of 1W and 2W can be considered more appropriate alternatives to HF acid etching for zirconium surface treatment prior to bracket bonding.

Orthodontic Wire Ingestion during Treatment: Reporting a Case and Review the Management of Foreign Body Ingestion or Aspiration (Emergencies).

Today orthodontic treatment is in growing demand and is not limited to a specific age or social group. The nature of orthodontic treatment is such that the orthodontic wires and appliances, which are used to apply force and move the teeth, are exposed to the oral cavity. Shaping and replacing these wires in oral cavity are the major assignments of orthodontist on appointments. Therefore, we can say that orthodontic treatment requires working with dangerous tools in a sensitive place like oral cavity which is the entrance of respiratory and digestive systems. In this paper, a case of ingesting a broken orthodontic wire during eating is reported, and also necessary remedial measures at the time of encountering foreign body ingestion or aspiration are provided.