Evaluation of dentinogenesis inducer biomaterials: an in vivo study

Abstract When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of 99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

Biological response of pulps submitted to different capping materials / Resposta biológica de polpas submetidas a diferentes materiais capeadores

Pulp capping is a procedure that comprises adequate protection of the pulp tissue exposed to the oral environment, aiming at the preservation of its vitality and functions. This study evaluated the response of the dental pulps of dog teeth to capping with mineral trioxide aggregate (MTA) or calcium hydroxide P.A. For that purpose, 37 teeth were divided into two groups, according to the capping material employed. Two dogs were anesthetized and, after placement of a rubber dam, their pulps were exposed in a standardized manner and protected with the experimental capping materials. The cavities were then sealed with resin-modified glass ionomer cement and restored with composite resin. After sixty days, the animals were killed and the specimens were processed in order to be analyzed with optic microscopy. It was observed that MTA presented a higher success rate compared to calcium hydroxide, presenting a lower occurrence of infection and pulp necrosis.

O capeamento pulpar é um procedimento que consiste na adequada proteção do tecido pulpar exposto ao meio oral, objetivando a preservação de sua vitalidade e suas funções. O objetivo deste trabalho foi observar a resposta da polpa dental de cães ao capeamento com o agregado de trióxido mineral (MTA) ou hidróxido de cálcio P.A. Para tanto, 37 dentes foram divididos em dois grupos, de acordo com o material capeador utilizado. Dois cães foram anestesiados e após o isolamento absoluto do campo operatório, realizou-se exposição padronizada da polpa, proteção com os materiais capeadores testados e selamento das cavidades com cimento modificado de ionômero de vidro. Os dentes foram então restaurados com resina composta. Após sessenta dias, os animais foram sacrificados e as peças foram processadas para a análise microscópica dos dentes. Observou-se que o MTA apresentou maior índice de sucesso em relação ao hidróxido de cálcio, evidenciando menor ocorrência de infecção e necrose pulpar.