Viability of using enamel and dentin from bovine origin as a substitute for human counterparts in an intraoral erosion model

This study ascertained whether under dental erosion models that closely mimics the real-life situation enamel and root dentin from bovine origin would be reliable substitutes for human counterparts. Through a 2x2 crossover design, in a first trial, 14 volunteers wore a palatal device containing slabs of bovine and human enamel. Half of the participants ingested (4x daily, for 10 days) orange juice first, crossing over to mineral water, while the remainder received the reverse sequence. In a second trial, volunteers wore devices with slabs of bovine and human root dentin. Except for the duration of each intraoral phase, which lasted 2 rather 10 days, the experiment with root dentin run exactly as for enamel. Dental substrates were analyzed for surface microhardness. Two-way ANOVAs (α=0.05) indicated no difference between the microhardness values recorded for human and bovine enamel (p=0.1350), but bovine root dentin had lower microhardness compared to its human counterpart (p=0.0432). While bovine enamel can reliably substitute its human counterpart in in situ dental erosion models, bovine root dentin does not seem to be a viable alternative to the corresponding human tissue.

Este estudo visou avaliar, sob um modelo de erosão dental que se aproxima da realidade clínica, se o esmalte e a dentina radicular bovinos seriam substitutos viáveis aos correspondentes substratos de origem humana. De acordo com um delineamento crossover 2x2, 14 voluntários utilizaram dispositivos palatinos contendo fragmentos de esmalte humano e bovino. Metade dos participantes ingeriu suco de laranja (4x/dia, por 10 dias) e, a seguir, alternou para a ingestão de água mineral, enquanto os demais voluntários receberam a seqüência reversa. Em um segundo experimento, os sujeitos da pesquisa fizeram uso do dispositivo palatino contendo fragmentos de dentina radicular bovina e humana. Exceto pela duração de cada uma das duas fases experimentais (2 ao invés de 10 dias), utilizou-se o mesmo protocolo empregado no estudo em que se comparou o esmalte. Os substratos dentais foram avaliados quanto a sua microdureza superficial. ANOVAs a dois critérios (α=0,05) não indicaram diferença entre os valores de microdureza observados para o esmalte humano e bovino (p=0,1350), porém a dentina radicular apresentou microdureza inferior à humana (p=0,0432). Enquanto o esmalte bovino é um substituto fidedigno do substrato humano em modelos in situ de erosão dental, a dentina radicular bovina não parece ser uma alternativa viável ao tecido humano correspondente.

The authors are especially grateful for the valuable participation and cooperation of the volunteers. Thanks are also due to Patricia Marchi, for her technical assistance, and to the Ethylene Oxide Sterilization Center of the Clinical Hospital of the School of Medicine of Ribeirão Preto (USP), for sterilizing the dental slabs. The State of São Paulo Research Foundation (FAPESP, grant #05/01515-8) is acknowledged for providing financial assistance in the form of a scholarship to the first author. This research was partially funded by a grant from the First Projects Program (MCT/CNPq-FAPESP, grant #06/60356-0).