Influence of dental exposure to oral environment on smear layer removal and collagen exhibition after using different conditioning agents

Abstract

Although in vitro studies have shown encouraging results for root surface conditioning with demineralizing agents, in vivo studies have failed to show its benefits in periodontal healing. This can be attributed to several factors, among which, the hypermineralization of dental surface. Therefore, this in vitro study compared, using scanning electron microscopy (SEM), the effect of root surface conditioning with different conditioners (1% and 25% citric acid, 24% EDTA and 50 mg/mL tetracycline hydrochloride) in impacted teeth and in teeth that had their roots exposed to the oral environment. One trained examiner assessed the SEM micrographs using a root surface modification index. There was a tendency of more root surface modification in the group of impacted teeth, suggesting that the degree of root mineralization influences its chemical demineralization.

In vitro evaluation of gingival fibroblasts proliferation and smear layer formation in pre-conditioned root surfaces

“…Many studies have shown that co-treatment with citric acid for two minutes results in exposure of the dentin tubules, leading to intertubular dentin surface porosity, which corresponds to exposed collagen fibers and proteoglycans 7,16,10 . In the present study citric acid at 10% was used demonstrating a capacity to expose root surface collagen, similarly to Blomlof and coworkers study 5 On the other hand Fontanari et al 22 used a 1% citric acid solution for 1 minute and were not able to demonstrate effective demineralization when applying it to the root surface. However, in this study, the group in which 10% citric acid was used for three minutes presented a greater dentin tubule exposure when compared to the control group, despite an incomplete removal of the smear layer.…”

“…In the present study, one may observe that when compared to the other groups, the application of 24% EDTA for three minutes achieved an increased dentinal tubule exposure, with a larger diameter, due to a significant, though not complete, removal of the smear layer. Similarly, other studies have demonstrated a demineralized root surface when using 24% EDTA for three minutes 22 with removal of the smear layer and exposure of the dentin matrix 16 . Many studies have shown that co-treatment with citric acid for two minutes results in exposure of the dentin tubules, leading to intertubular dentin surface porosity, which corresponds to exposed collagen fibers and proteoglycans 7,16,10 .…”

“…Over the years, scaling and root planning has been proposed to promote a biocompatible root surface for the adjacent periodontal tissues 10,[21][22] . However, this conventional approach produces a fine smear layer over the root surface, which may compromise tissue healing 5,8,10 .…”

Efeitos do condicionamento ácido na descontaminação da superfície radicular e no recobrimento radicular: análise em MEV e estudo clínico randomizado

“…Assim, o grau de mineralização das superfícies dentinárias influencia a desmineralização química (FONTANARI et al, 2011), o que poderia explicar a existência de resultados variáveis, especialmente em estudos clínicos envolvendo pacientes periodontalmente comprometidos.…”

Efeito da desmineralização óssea sobre parâmetros de superfície e sobre o comportamento de pré-osteoblastos em cultura: estudo em microscopia eletrônica de varredura e confocal

“…Como muitas superfícies desmineralizadas com o ácido a 50 % apresentavam uma camada de reprecipitação, foi especulado que esse seria um fator negativo a sugerir que, em concentrações mais altas da solução ácida usada na desmineralização, podem ocorrer alterações nas superfícies radiculares que não são compatíveis com a inserção e diferenciação celular (FONTANARI et al, 2011;LAN et al, 1999, ROMPEN;GOFFINET;NUSGENS, 1999). A mesma camada de reprecipitação já havia antes sido observada por Amaral et al (2011) sobre superfícies de dentina condicionadas com ácido fosfórico a 37 % durante 3 minutos, a qual foi atribuída a uma provável precipitação de sais de fosfato de cálcio decorrente da saturação gradativa do ácido durante esse longo tempo de desmineralização.…”