The aim of this in vitro study was to evaluate the tensile bond strength of a self-etching adhesive system to three different dentinal substrates. Primary molar teeth that had been recently exfoliated (RE), with unknown time of exfoliation (UT), and extracted due to prolonged retention (PR) were used for this investigation. Ten primary molar teeth of each group were cut in the middle following the mesio-distal direction, creating a total of twenty specimens per group. The specimens were included in acrylic resin and had a flat dentin surface exposed. The self-etching adhesive system was applied to this surface and a 3-millimeter high cone with diameter of 2 mm in the adhesion area was constructed using composite resin. The specimens were stored in distilled water at 37ºC for 24 hours. Fifteen specimens of each substrate were used for the tensile bond test (n = 15) and 5 had the interface analyzed by scanning electron microscopy (SEM). The data was examined by one-way ANOVA and presented no significant differences between groups (p = 0.5787). The mean values obtained for RE, UT and PR were 18.39 ± 9.70, 19.41 ± 7.80, and 23.30 ± 9.37 MPa, respectively. Any dentinal substrates of primary teeth studied are safe for tensile bond strength tests with adhesive systems.

DIAGNOdent é um aparelho de fluorescência a laser usado para o diagnóstico de lesões de cárie dentária em superfícies oclusais e lisas. Apesar dos resultados preliminares promissores, as moléculas envolvidas no aumento da fluorescência em lesões de cárie permanecem sem explicação. O objetivo deste estudo foi comparar as leituras com o aparelho de fluorescência a laser antes e depois de alterações no conteúdo orgânico de lesões de cárie oclusal em dentes decíduos. Vinte e quatro molares decíduos armazenados em soro fisiológico com pelo menos um sítio com lesão de cárie oclusal foram divididos em dois grupos. O grupo controle foi composto de 17 sítios com cárie, e o grupo experimental, 16 sítios. As lesões de cárie foram medidas com o aparelho de fluorescência a laser. As amostras do grupo experimental foram então removidas da solução de armazenamento e imersas em uma solução de hipoclorito de sódio a 2% por 24 horas. Depois da lavagem com água, os dentes foram medidos novamente com o aparelho de fluorescência a laser. Os dentes do grupo controle foram submetidos aos mesmos procedimentos, mas soro fisiológico foi usado em vez de hipoclorito de sódio. Uma redução estatisticamente significante na média das leituras depois da imersão nas duas soluções testadas comparadas às primeiras leituras de ambos os grupos foi observada, mas a porcentagem de redução foi estatisticamente maior no grupo experimental (p < 0,0001). Neste estudo, os dados indicam que alterações na fluorescência de lesões de cárie medidas pelo aparelho de fluorescência a laser ocorrem principalmente devido a alterações no conteúdo orgânico ao invés da perda mineral.

DIAGNOdent is a laser fluorescence device used for dental caries diagnosis in occlusal and smooth surfaces. Despite the promising preliminary results, the molecules involved in the increase of fluorescence in carious lesions remain unclear. The aim of this study was to compare the laser fluorescence readings before and after changes in the organic material of occlusal carious lesions in primary teeth. Twenty-four primary molars stored in saline solution with at least one site with occlusal caries were divided into two groups. The control group had 17 sites with caries and the experimental one had 16 sites. The carious lesions were measured with laser fluorescence. The experimental samples were then removed from the storage solution and immersed in a 2% sodium hypochlorite solution for 24 hours. After washing with water, the teeth were measured again with the laser fluorescence device. The teeth of the control group were submitted to the same procedures, but saline solution was used instead of the sodium hypochlorite solution. A statistically significant reduction in the mean of the readings after immersion in the two tested solutions compared with the initial readings was observed in both groups, but the decrease was statistically higher in the experimental group (p < 0.0001). In this study, the data indicate that changes in the fluorescence of carious lesions measured by the laser fluorescence are mainly due to the organic content alterations rather than to the mineral loss.