RESUMEN
PURPOSE: Factors affecting the retention of fixed prostheses to natural abutments are well understood. In contrast, little is known concerning the factors influencing the retention of fixed prostheses cemented to implant abutments. The purpose of this study was to investigate the effect that extending a casting into the screw access channel of an implant abutment has on the retention when cemented using Temp Bond. MATERIALS AND METHODS: Replace Select Straight abutments received set modifications (buccal wall removal at 15 degrees , 22 degrees , and 30 degrees ) using a milling machine; controls were unmodified. Two castings were fabricated for each of the modified abutments, one with and one without an extension into the screw access channel. Following cementation with Temp Bond under standardized conditions, the castings were removed from the abutments using an Instron machine, and the peak removal force was recorded. RESULTS: Extending the casting into the screw access channel significantly (p < 0.001) increased the peak load of removal. Significant differences (p < 0.05) were found between no modification and 30 degrees modification, 15 degrees and 30 degrees modification, and 22 degrees and 30 degrees modification in the groups when the casting extended into the abutment. In the group where the casting did not extend into the abutment, all groups were significantly different (p < 0.001) with the exception of 22 degrees and 30 degrees modification. CONCLUSIONS: The increased load required to remove a casting that extends into the screw access channel of an implant abutment may compensate for loss in retention, which occurs through unfavorable modification of the abutment.
Asunto(s)
Cementación/métodos , Pilares Dentales , Implantes Dentales , Diseño de Prótesis Dental , Retención de Prótesis Dentales , Revestimiento para Colado Dental/química , Técnica de Colado Dental , Restauración Dental Provisional , Análisis del Estrés Dental/instrumentación , Eugenol/química , Aleaciones de Oro/química , Humanos , Ensayo de Materiales , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción , Óxido de Zinc/química , Cemento de Óxido de Zinc-Eugenol/químicaRESUMEN
Hydrogen peroxide in the form of carbamide peroxide is widely used in professionally and self-administered products for tooth whitening. Hydrogen peroxide is a highly reactive substance that can damage oral soft and hard tissues when present in high concentrations and with exposures of prolonged duration. This review examines the issue of oral mucosal damage and possible carcinogenicity relating to the use of hydrogen peroxide in the mouth for tooth whitening, with an emphasis on safety with prolonged exposure to low concentrations of peroxide products.