The aim of the present study was to evaluate histologically the pulp response of anionic lyophilized collagen matrix with or without hydroxyapatite as a biomaterial pulp-capping agent in pulpotomy of dogs' teeth. Sixty pre-molar roots from three dogs were used. After pulpotomy, the remaining pulp tissue was capped with one of the following materials: Group I (20 roots): anionic lyophilized collagen matrix; Group II (20 roots): anionic lyophilized collagen matrix associated with hydroxyapatite; Group III (10 roots): calcium hydroxide (p.a.) paste in saline; Group IV (10 roots): zinc oxide eugenol cement. After 90 days the animals were killed by anesthetic overdose and the teeth were removed and submitted to histological processing. According to the histopathological results, we concluded that the zinc oxide eugenol cement and anionic lyophilized collagen matrix with or without hydroxyapatite did not present satisfactory pulp response and that calcium hydroxide is the suitable material for pulpotomy.

O objetivo deste estudo foi avaliar, por meio de cultura bacteriológica, a prevalência de microorganismos em 31 canais radiculares de dentes decíduos humanos com necrose pulpar e lesão periapical. O material, colhido dos canais radiculares após a realização da cirurgia de acesso, foi submetido ao processamento microbiológico para a determinação das unidades formadoras de colônia de microorganismos. Os resultados mostram que os microorganismos anaeróbios foram quantificados em 96,7% dos casos, os bacilos pigmentados de negro (BPB) em 35,5%, os aeróbios em 93,5%, os estreptococos em 96,7% e os S. mutans em 48,4%. Assim, pôde-se concluir que a infecção em canais radiculares de dentes decíduos humanos portadores de necrose pulpar e lesão periapical é polimicrobiana, com grande quantidade de microorganismos e maior prevalência de estreptococos e microorganismos anaeróbios.

The objective of this study was to evaluate bacterial prevalence in 31 root canals of human deciduous teeth with necrotic pulp and periapical lesions using bacterial culture. After crown access, the material was collected using absorbent paper points for microbiological evaluation and determination of colony forming units (CFU). Anaerobic microorganisms were found in 96.7% of the samples, black-pigmented bacilli in 35.5%, aerobic microorganisms in 93.5%, streptococci in 96.7%, and S. mutans in 48.4%. We concluded that in human deciduous teeth root canals with necrotic pulp and periapical lesions the infection is polymicrobial, with a large number of microorganisms and a predominance of streptococci and anaerobic microorganisms.