Effects of Crest Whitestrips bleaching on surface morphology and XXXX susceptibility of teeth in vitro.

@entity1 @entity174 @entity2625 @entity273 @entity12946
OBJECTIVE: This study examined the effects of @entity2625 tooth bleaching, including Crest Whitestrips @entity273 treatments, on the @entity174 susceptibility and surface morphology of @entity1 tooth enamel in vitro. METHODOLOGY: Extracted @entity1 molars were ground and polished to prepare a uniform substrate for bleaching treatments. A cycling treatment methodology was employed which alternated ex vivo @entity1 salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching treatments included commercial Crest Whitestrips bleaching gels, which utilize @entity273 as the in situ bleaching source, and several commercial @entity12946 bleaching gels. Control treatments included placebo gels and an untreated group. Crest Whitestrips bleaching included treatment exposures simulating recommended clinical exposures (14 hours of bleaching), along with excess bleaching simulating exposure to five times the suggested Crest Whitestrips use. At the conclusion of treatments, surface color measurements were taken to ensure tooth bleaching. Surface microhardness measures and surface morphological assessments with SEM were conducted to assess the effects of bleaching exposure on the surface morphology and mineral integrity of the teeth. These latter measures were then complemented with assessments of @entity174 susceptibility utilizing detailed analyses of crack propagation resulting from post-treatment microhardness indentations. RESULTS: Surface microhardness and SEM measures revealed no deleterious effects on the enamel surfaces from any of the bleaching products assessed. This included conditions of excess bleaching exposure or "overbleaching." The analysis of @entity174 susceptibility similarly revealed no significant effects from tooth bleaching, regardless of the @entity2625 source. CONCLUSIONS: These results confirm that tooth bleaching from the selected commercial @entity273 or @entity12946 bleaching systems do not produce changes in surface morphology, microhardness or @entity174 susceptibility of @entity1 tooth enamel under in vitro cycling conditions of treatment matching clinical bleaching exposures. These results support the clinical safety of the selected commercial bleaching systems to vital dentition, matching results obtained from the long-term use of these ingredients applied in dental offices and available in commercial formulations.
