Histological evaluation of swine dental pulp after their capping either with mineral trioxide aggregate or calcium hydroxide

O presente trabalho teve como objetivos avaliar o uso de su??nos da esp??cie Sus scrofa domesticus para experimentos em polpa dental e analisar a resposta histol??gica pulpar mediante a aplica????o direta de agregado tri??xido mineral (MTA Angelus??) e cimento contendo Hidr??xido de C??lcio (Dycal??). Cavidades classes V foram preparadas em dentes incisivos e pr??-molares dec??duos inferiores de su??nos oriundos do cruzamento de ra??as Landrace e Large White com idade aproximada de 105 dias (??10 dias). Exposi????es pulpares foram obtidas e ap??s hemostasia com soro fisiol??gico, foi realizado capeamento pulpar com a aplica????o direta de MTA ou Dycal. Os animais foram abatidos ap??s o per??odo de 7 ou 70 dias de acordo com a ISO 7405:1997. Quatro grupos foram criados a partir da combina????o de tempos e materiais (HC_7d, HC_70d, MTA_7d e MTA_70d). Os dentes foram extra??dos e processados pela t??cnica histol??gica de HE, com cortes aleatorizados sendo examinados ao microsc??pio ??ptico em 100x de aumento por dois examinadores. Os crit??rios avaliados foram: resposta inflamat??ria, organiza????o tecidual, dentina reacional e reparativa, classificados de acordo com os crit??rios da ISO 7405:1997. Foi utilizado o teste estat??stico de Mann-Whitney para realizar as compara????es entre dois grupos (?=5%). O MTA demonstrou uma tend??ncia em acelerar o processo de regenera????o pulpar, iniciando a deposi????o de dentina reparativa ainda nas primeiras fases do reparo. Ambos materiais apresentaram caracter??sticas de reparo pulpar similar ap??s 70 dias. Apesar de maiores n??veis significantes deinflama????o inicial, especialmente associado ao Hidr??xido de C??lcio (p< 0,05), houve uma marcante forma????o de dentina terci??ria ao final de 70 dias, demonstrando a capacidade da polpa dental de su??nos em responder aos est??mulos provocados pelos materiais utilizados. O tipo de animal empregado parece fornecer um modelo economicamente vi??vel para estudos de resposta pulpar.The main objectives of this study were to evaluate the use of the Sus scrofa domesticus swine in dental pulp experiments and analyze the histological pulp reaction to the direct application of mineral trioxide aggregate (MTA Angelus) and cement containing calcium hydroxide (Dycal). Class V cavities were prepared on incisors and pre-molar deciduous teeth of swine originated from crossbreed between Landrace and Large White of about 105 (??10 days) days old. Pulp exposures were obtained and after their homeostasis with saline, pulp capping was done with direct application of either MTA or Dycal. The animals were slaughtered after a period ranging within 7 and 70 days according to ISO 7405:1997. Four groups were created combining times and materials (HC_7d, HC_70d, MTA_7d and MTA_70d). The teeth were extracted and processed by HE histological technique; randomized cuts were examined under optical microscope with 100X enlargement by two different examiners. The criteria evaluated were: inflammatory response, tissue organization, reactive and reparative dentin being them all classified according to ISO 7405:1997 criteria. The Mann-Whitney Statistical test was used to compare both groups (&#945;=5%). The MTA showed a tendency to accelerate the pulp healing process, being reparative dentin apposition initiated in the early stages of the healing process. Both materials showed similar pulp healing characteristics after 70 days. Despite higher levels of initial inflammation, specially related to Calcium Hydroxide (p