In situ evaluation of enamel-dentin erosion by beverage and recovery by saliva

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe erosive effect of soft drinks on enamel-dentine and the saliva capacity in repairing the alterations was evaluated considering the model adequacy and the absence of research in relation to dentine. Nine volunteers, wearing intra-oral palatal appliances containing 4 enamel and 4 radicular dentine blocks from bovine incisors, participated in this study of 5 phases, in which Coca-Cola (Coke) was consumed from 1 to 8 times/day. Superficial microhardness (SMH) determinations were performed with loads of 50.0 and 15.0 g, respectively for enamel and dentine. The analyses were made: a) 2 h after saliva action; b) after the last intake of coke; c) 24 h after saliva action. The results showed that in function of frequency of coke ingestion, the percentage of microhardness change (% SMHC) ranged from 18.7 to 27.9 for enamel and from 24.6 to 32.6 for dentine. These reduction were statistically significant at 5% (paired t test). The percentage of microhardness recovery (% SMHR) by saliva action was significant (p < 0.05) and ranged from 43.6 to 35.6 for enamel and from 40.5 to 34.6 for dentine. However, statistical analysis showed that total recovery was not significant (p > 0.05). There was also a significant correlation between frequency of Coca-Cola ingestion and % SMHC, being 0.97 for enamel and 0.72 for dentine. On the other side, in relation to % SMHR the correlation was negative, -0.70 for enamel and -0.74 for dentine. It was concluded that in function of frequency of Coca-Cola ingestion there are proportional and irreversible losses of superficial structure either in the enamel or in the dentineO objetivo do presente trabalho foi uma avaliação intra-oral do efeito erosivo de refrigerante no esmalte-dentina e a capacidade da saliva em reverter as alterações, considerando a adequação do modelo e a inexistência de pesquisas em relação à dentina. Para tanto, foram utilizados dentes bovinos, a partir dos quais prepararam-se blocos de esmalte e dentina radicular adequados para determinação de microdureza superficial. Nove voluntários, utilizando dispositivos intra-orais palatinos contendo 4 blocos de esmalte e 4 de dentina, participaram deste estudo de 4 etapas, nas quais Coca-Cola foi ingerida de 1 a 8 vezes ao dia. Foram feitas determinações de microdureza superficial utilizando-se o aparelho SHIMADZU HMV 2000, e cargas de 50,0 e 15,0 g, respectivamente para esmalte e dentina, durante 5,0 segundos. Os resultados mostraram que, em função da freqüência de ingestão de Coca-Cola, a porcentagem de perda de dureza foi de 18,7 a 27,9 para o esmalte e de 24,6 a 32,6 para a dentina. Estas reduções foram estatisticamente significativas a 5% (teste t pareado). A porcentagem de recuperação de dureza pela ação da saliva foi parcial, porém significativa (p < 0,05), variando de 43,6 a 35,6 para o esmalte e de 40,5 a 34,6 para a dentina. Houve também uma correlação significativa entre freqüência de ingestão de Coca-Cola e % de perda de dureza, sendo de 0,97 para o esmalte e de 0,72 para a dentina. Por outro lado, em termos de recuperação de dureza, a correlação foi negativa, -0,70 para o esmalte e -0,74 para a dentina. Conclui-se que em função da freqüência de ingestão de Coca-Cola há perdas proporcionais e irreversíveis da estrutura superficial tanto do esmalte como da dentina132127134FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informaçãoThe erosive effect of soft drinks on enamel-dentine and the saliva capacity in repairing the alterations was evaluated considering the model adequacy and the absence of research in relation to dentine. Nine volunteers, wearing intra-oral palatal appliances containing 4 enamel and 4 radicular dentine blocks from bovine incisors, participated in this study of 5 phases, in which Coca-Cola (Coke) was consumed from 1 to 8 times/day. Superficial microhardness (SMH) determinations were performed with loads of 50.0 and 15.0 g, respectively for enamel and dentine. The analyses were made: a) 2 h after saliva action; b) after the last intake of coke; c) 24 h after saliva action. The results showed that in function of frequency of coke ingestion, the percentage of microhardness change (% SMHC) ranged from 18.7 to 27.9 for enamel and from 24.6 to 32.6 for dentine. These reduction were statistically significant at 5% (paired t test). The percentage of microhardness recovery (% SMHR) by saliva action was significant (p < 0.05) and ranged from 43.6 to 35.6 for enamel and from 40.5 to 34.6 for dentine. However, statistical analysis showed that total recovery was not significant (p > 0.05). There was also a significant correlation between frequency of Coca-Cola ingestion and % SMHC, being 0.97 for enamel and 0.72 for dentine. On the other side, in relation to % SMHR the correlation was negative, -0.70 for enamel and -0.74 for dentine. It was concluded that in function of frequency of Coca-Cola ingestion there are proportional and irreversible losses of superficial structure either in the enamel or in the dentin