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

Tissue response to direct pulp capping with calcium hydroxide preceded by corticosteroid or corticosteroid/antibiotic dressing: a histological study in rats / Resposta do tecido pulpar à aplicação da pasta à base de hidróxido de cálcio precedida do emprego do curativo de corticosteróide ou corticosteróide/antibiótico: estudo histológico em ratos

Purpose: This study histologically evaluated the reaction of tooth pulp to treatment with calcium hydroxide in distilled water preceded by a corticosteroid (Decadron) or corticosteroid/antibiotic (Otosporin) dressing. Methods: Calcium hydroxide solution was applied to exposed tooth pulp for 5 min or for 72 h, using a sample of 120 molars of rats; histological examination was performed 7, 14, 30 and 60 days after treatment. Results: A mild inflammatory reaction was observed at 7 and 14 days whether the dressings were used for 5 min or for 72 h. When the corticosteroid/antibiotic dressing was used for 5 min, the tissue reaction and the mineralized barrier formed at 30 and 60 days were similar to those of animals in the control group. Use of the corticosteroid dressing for 5 min or 72 h or the corticosteroid/antibiotic dressing for 72 h delayed healing of the pulp tissue. Conclusion: Temporary dressings resulted in a milder inflammatory reaction during the early postoperative period. The tissue reaction and the quality of the barrier formed when the Otosporin temporary dressing was applied for 5 min were similar in the experimental and the control groups at longer postoperative periods. Temporary dressings of Decadron applied for 5 min or 72 h or Otosporin applied for 72 h caused a slight retardation of the healing process of the tissue that was apparent 30 days after the intervention.

Objetivo: Avaliar a reação pulpar à pasta de hidróxido de cálcio em água destilada, precedida de curativo de corticosteróide (Decadron) ou corticosteróide/antibiótico (Otosporin) por 5 min ou 72 h. Metodologia: Em 120 polpas de dentes de ratos expostas, a análise histológica foi realizada após 7, 14, 30 e 60 dias de cada tratamento. Resultados: Nos períodos iniciais observou-se leve reação inflamatória quando os curativos foram aplicados por 5 min ou 72 h. A reação tecidual e a barreira formada sob ação do hidróxido de cálcio após o curativo de Otosporin por 5 min foram semelhantes àquelas do grupo controle aos 30 e 60 dias. Os curativos de demora com Decadron por 5 min e 72 h e Otosporin por 72 h promoveram retardo no processo de reparação. Conclusão: Os curativos de demora promoveram reação inflamatória mais suave nos períodos iniciais de análise. A reação tecidual e a qualidade da barreira formada sob a ação do Otosporin por 5 min foram semelhantes àquelas do grupo controle nos períodos pós-operatórios mais longos. Os curativos de demora com Decadron por 5 min e 72 h e Otosporin por 72 h promoveram ligeiro retardo no processo de reparação tecidual a partir de 30 dias.

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.

El hidróxido de calcio y su empleo en odontología / The use of calcium hydroxide in dentistry

La odontología moderna y actual no solamente se preocupa de diagnosticar y tratar las afecciones bucodentales, eliminando las causas que provocan desequilibrio orgánico, sino que también actúa protegiendo las estructuras y tejidos remanentes con un sinfín de medicamentos, sustancias y materiales. Estos elementos tienen la particularidad de poseer doble función: protectora y aislante, a la vez de promover la recuperación y consiguiente reparación de los tejidos dentarios sobre los cuales actúa. Este es precisamente el caso del hidróxido de calcio, un material cuya singular característica, la biocompatibilidad y sus otras propiedades benéficas para las piezas dentarias, fueron analizadas y comprobadas a través de los años y de las experiencias que le dan un lugar indiscutible dentro de los materiales de uso odontológico