Abstract The present study aimed to investigate the use of platelet-rich plasma (PRP) on tooth extraction sites in rats treated with bisphosphonates. Thirty Albinus Wistar male rats were administered 0.035 mg/kg zoledronic acid intravenously for 8 weeks, divided into four administrations with a 2-week interval between each application, after which their upper right central incisors were extracted to induce the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). The samples were divided into the following two groups: Group 1 (G1) underwent marginal resection of BRONJ followed by the use of PRP, while Group 2 (G2) underwent resection of BRONJ but without the use of PRP. The treatment groups were evaluated after 14, 28, and 42 days. Clinical, microtomographic, microscopic, and immunohistochemical (IHC) evaluations were performed. Microtomography results revealed no significant difference between the groups (p <0.05) in any time period. Histomorphometric analysis showed increased bone formation over time for both groups (p < 0.001). G1 demonstrated a greater amount of new bone formation than G2 at 28 and 42 days (p < 0.001), with G1 presenting greater vascularization and a slightly higher VEGF expression. For both groups, RANKL/OPG expression levels were sufficient as a parameter for indicating the rate of bone remodeling in a previously treated area of osteonecrosis groups. Taken together, our findings indicated that the use of PRP improves the resolution process of BRONJ.

Abstract It is largely known that some oral diseases can be diagnosed based upon their clinical manifestation combined with the patient's medical history and generally not depending on examination. This is the case of some bone diseases such as osteoradionecrosis of the jaw (ORNJ), osteomyelitis of the jaw (OMJ), and medication-related osteonecrosis of the jaw (MRONJ). The present study aimed to analyze the histopathological features of these specific bone diseases in order to evaluate similarities and differences. Forty-four bone specimens resected from each bone disease (22 cases of ORNJ, 6 cases of OMJ, and 16 cases of MRONJ) were analyzed by two experienced oral pathologists without prior knowledge of the diagnosis, considering bone tissue condition, inflammation, vascularization, and the presence of microorganisms. In addition, the examiners formulated a diagnostic hypothesis for each specimen. Many histopathological similarities were found among the diseases, especially considering the presence of necrotic bone, inflammation, and microorganisms. Statistically significant differences were detected in empty bone lacunae, which was decreased in ORN (p = 0.042), and considering neutrophil count, which was low in the MRONJ group (p ≤ 0.001). The Kappa coefficient was calculated and agreement was detected based on the histopathological parameters, but not for diagnostic suggestion (p=0.23). In conclusion, histopathological aspects of ORNJ, OMJ, and MRONJ do not permit a conclusive diagnosis, emphasizing the necessity of a detailed clinical report.

Resumo Introdução Durante o reparo de enxertos ósseos, diferentes taxas de reabsorção são mediadas pelos osteoclastos e podem ser afetadas pelos bisfosfonatos, que são drogas que agem como inibidores da reabsorção óssea. Objetivo Avaliar a taxa de reabsorção dos enxertos ósseos de calota craniana de coelhos, com e sem o uso alendronato de sódio. Material e método Trinta e dois coelhos Nova Zelândia foram divididos igualmente em 2 grupos (grupo controle e grupo alendronato de sódio) e subdivididos em 4 períodos (7, 14, 30 e 60 dias). O grupo controle não recebeu alendronato, enquanto os animais do grupo experimental receberam 4 mg de alendronato de sódio por semana, em dose única, após a cirurgia. Um bloco de osso de diâmetro de 8 mm foi retirado o osso parietal e fixado com parafuso no osso parietal contralateral. Após cirurgia, nos períodos de 7, 14, 30 e 60 dias, os animais foram eutanasiados e as peças removidas para análise. Análises morfológica e histomorfométrica foram utilizados para comparar a espessura do enxerto e para avaliar a interface de osso recém formado entre o enxerto ósseo e o sítio receptor. Os testes de Wilcoxon e Mann-Whitney foram utilizados para as análises estatísticas. Resultado Todos os enxertos repararam e integraram sem intercorrências; não foram detectadas diferenças estatisticamente significativas nas taxas de reabsorção ou deposição óssea, após a incorporação final do enxerto em ambos os grupos. Conclusão Alendronato de sódio parece não diminuir a taxa de reabsorção, porém houve uma tendência de resultados melhores no grupo controle tanto na reabsorção quanto na neoformação óssea em enxertos ósseos autógenos de calota craniana de coelhos.

Abstract Introduction Different rates of resorption are mediated by osteoclasts that may be affected by bisphosphonates during bone graft repair. Bisphosphonates are drugs that act as inhibitors of bone resorption. Objective The aim of the present study was to evaluate the rate of resorption of skullcap grafts in rabbits with and without the use of alendronate sodium. Material and method Thirty two New Zealand rabbits were divided into two groups (control group and alendronate group) and divided again into four periods (7, 14, 30 and 60 days). The control group did not receive alendronate, while animals of the experimental group received 4 mg of alendronate sodium weekly after the surgery. An 8 mm diameter bone block was removed from the parietal bone and fixed by screws to the contralateral parietal bone. During the periods of 7, 14, 30 and 60 days, the animals had undergone euthanasia and samples were removed for further analysis. Morphological and histomorphometric tests were used to compare graft thicknesses and to evaluate the newly formed bone at the interface between the graft and receptor site. The Wilcoxon and Mann-Whitney tests were used for statistical analyses. Result All grafts healed and integrated uneventfully and no statistically significant differences in resorption rates or bone deposition were detected after the final incorporation of the graft in both groups. Conclusion Alendronate Sodium did not decrease the bone graft resorption rates, but there was a tendency for better results in the control group regarding the resorption and neoformation in autogenous calvarial bone grafts in rabbits.

ABSTRACT PURPOSE : To evaluate a modified experimental model for medication-related osteonecrosis of the jaw (MRONJ) through the upper right central incisor extraction followed by intravenous bisphosphonate administration. METHODS: Forty five rats underwent the upper right central incisor tooth extraction were divided in 2 groups: Group I - experimental group, 30 rats received an intravenous administration protocol of zoledronic acid 35μg/kg into the tail vein every two weeks, totalizing four administrations, during eight weeks of administration, previously the extraction, and Group II - control group, 15 rats didn't received any medication before extraction. The groups were subdivided in postoperative periods: 14/28/42 days. Clinical analysis and microtomography were performed to verify the presence of osteonecrosis. In addition, descritive histological analysis of hematoxylin-eosin stained sections was performed to evaluate the presence of osteonecrosis or necrotic foci. RESULTS: Twelve (40%) rats, from experimental group, showed clinical signs of MRONJ (p=0.005), however, all samples showed imaginologic findings like osteolysis and loss of integrity of the cellular walls (p≤0.001). Microscopic evaluation revealed osteonecrosis areas with microbial colonies and inflammatory infiltrate (p≤0.001). In the control group, all animals presented the chronology of a normal wound healing. CONCLUSIONS: The presence of medication-related osteonecrosis of the jaw after maxillary central incisor extraction in rats. This new experimental model may be considered an option for the study of MRONJ.

OBJETIVO: Apresentar as características clínicas, tratamento cirúrgico e achado histológico de um caso de lipoidoproteinose. DESCRIÇÃO DO CASO: Criança do sexo masculino, cinco anos de idade, branco, que procurou atendimento odontológico na Universidade. A mãe da criança relatou presença de intensa halitose e dificuldade na alimentação e higienização bucal, decorrentes de crescimento gengival generalizado nos arcos dentários superior e inferior. No exame clínico, verificaram-se comprometimento funcional e estético generalizado (rouquidão, artralgia bilateral no joelho e tornozelo, lesões tumorais nas orelhas, entre outros), além de extensa hiperplasia gengival em ambos os arcos dentários. Optou-se pelo tratamento cirúrgico, com remoção do tecido hiperplásico e exodontia de todos os dentes decíduos e de dois permanentes. O exame histopatológico da peça cirúrgica confirmou o diagnóstico de lipoidoproteinose. COMENTÁRIOS: A lipoidoproteinose é uma doença rara caracterizada pela deposição da substância hialina na pele, membranas mucosas e nos órgãos internos. Os sinais que podem surgir após o nascimento, são: rouquidão; lesões pápulo-nodulares na cabeça, pescoço e membros; lesões papulares amareladas nas margens das pálpebras. O curso desta doença é benigno e crônico.

OBJECTIVE: Report clinical characteristics, histological findings and treatment of a patient with lipoid proteinosis. CASE DESCRIPTION: Five year-old male patient was assisted in the university clinic for dental treatment. The mother reported the presence of intense halitosis and difficulties for feeding and oral hygiene due to extensive gingival hyperplasia on the maxillary and mandibular arches. Clinical examination revealed generalized functional and esthetic involvement, including hoarseness; bilateral knee and ankle arthralgia; tumoral lesions on the ears and gingival hyperplasia throughout the extent of both dental arches. The surgical treatment removed the hyperplastic tissue and all deciduous teeth, as well as two permanents teeth. Histopathological examination of the specimen confirmed the diagnosis of lipoid proteinosis. COMMENTS: Lipoid proteinosis is a rare disorder characterized by progressive deposition of hyaline material in the skin, mucous membranes and organs. Clinical signs appear after birth and are characterized by hoarseness, papulonodular lesions on the head, neck and limbs and yellowish papules on the eyelid margins, among others. The disease has a benign and chronic evolution.

A ostectomia é uma manobra cirúrgica fundamental que pode afetar a reparação tecidual de modo a aumentar a morbidade do procedimento. O tipo de equipamento e/ou instrumental utilizado para a ostectomia pode influenciar diretamente no reparo ósseo. O objetivo deste trabalho foi analisar o processo de reparação óssea em defeitos realizados em mandíbula de coelho com três diferentes equipamentos. Quinze coelhos foram aleatoriamente divididos em 3 grupos (n=5) de acordo com o equipamento usado para preparacão de 3 cavidades ósseas com brocas padronizadas: I) motor de baixa rotação pneumático, II) motor de alta rotação pneumático e III) motor de baixa rotação elétrico, todos com refrigeração constante. Após os períodos experimentais de 2, 7e 30 dias, as peças anatômicas foram removidas e submetidas a análises microscópica e histomorfométrica. Não houve diferença estatisticamente significante (p>0,05) entre os grupos nos 3 períodos experimentais, considerando-se a área total de matriz óssea mineralizada, embora a análise microscópica tenha revelado uma tendência a um processo de reparação óssea um pouco mais adiantado no grupo III, quando comparado aos demais grupos. Os resultados deste estudo sugerem que o tipo de equipamento rotatório utilizado em cirurgia bucomaxilofacial não interfere no reparo ósseo.

In oral surgery, the quality of bone repair may be influenced by several factors that can increase the morbidity of the procedure. The type of equipment used for ostectomy can directly affect bone healing. The aim of this study was to evaluate bone repair of mandible bone defects prepared in rabbits using three different rotary devices. Fifteen New Zealand rabbits were randomly assigned to 3 groups (n=5) according to type of rotary device used to create bone defects: I - pneumatic low-speed rotation engine, II - pneumatic high-speed rotation engine, and III - electric low-speed rotation engine. The anatomic pieces were surgically obtained after 2, 7 and 30 days and submitted to histological and morphometric analysis. The morphometric results were expressed as the total area of bone remodeling matrix using an image analysis system. Increases in the bone remodeling matrix were noticed with time along the course of the experiment. No statistically significant differences (p>0.05) were observed among the groups at the three sacrificing time points considering the total area of bone mineralized matrix, although the histological analysis showed a slightly advanced bone repair in group III compared to the other two groups. The findings of the present study suggest that the type of rotary device used in oral and maxillofacial surgery does not interfere with the bone repair process.

Recentemente, o agregado de trióxido mineral (MTA) regular e branco estão sendo utilizados na Odontologia como materiais para obturação retrógrada de canais radiculares. Testes de genotoxicidade e citotoxicidade formam uma importante parte da pesquisa do câncer e da avaliação de risco de carcinógenos potenciais. Assim, o objetivo deste estudo foi examinar a genotoxicidade e citotoxicidade do MTA branco e regular in vitro pelo teste do cometa e teste de exclusão pelo azul de tripan, respectivamente. Células do linfoma murino foram expostas às duas formas de apresentação do MTA nas concentrações finais de 1 a 1.000 µg/mL por 3 horas a 37°C. Os resultados mostraram que ambos os compostos testados não produziram efeito genotóxico em todas as concentrações testadas. Da mesma forma, nenhuma diferença estatisticamente significativa (p > 0,05) foi observada na citotoxicidade. Em suma, nossos resultados sugerem que o MTA regular e branco não são genotoxinas e não são capazes de interferir na viabilidade celular conforme avaliado pelo teste do cometa e ensaio do azul de tripan, respectivamente.

Recently, regular and white mineral trioxide aggregate (MTA) are being used in Dentistry as retrofilling materials. Genotoxicity and cytotoxicity tests form an important part of cancer research and risk assessment of potential carcinogens. Thus, the goal of this study was to examine the genotoxicity and cytotoxicity of regular and white MTA in vitro by the single cell gel (comet) assay and trypan blue exclusion test, respectively. Mouse lymphoma cells were exposed to two presentation forms of MTA at final concentrations ranging from 1 to 1,000 µg/mL for 3 h at 37°C. The results showed that both compounds tested did not produce genotoxic effects at all concentrations evaluated. Likewise, no statistically significant differences (p > 0.05) were observed in cytotoxicity. Taken together, our results suggest that regular and white MTA are not genotoxins and are not able to interfere in cellular viability as assessed by single cell gel (comet) assay and trypan blue assay, respectively.

Os autores avaliaram a resposta tecidual, em região subcutânea de ratos, frente a fios de sutura: poliglecaprone 25, poliglactina 910 e politetrafluoretileno. Para tanto foram utilizados 20 ratos Wistar albinus, onde praticou-se três pontos de sutura em planos profundos na região dorsal, com os diferentes materiais em estudo. Após períodos de 2, 7, 14 e 21 dias, grupos de cinco animais foram sacrificados para obtenção de espécimes que foram processados e corados pela hematoxilina e eosina. Na análise microscópica adotou-se como parâmetros o grau de fibrosamento, o índice de proliferação angioblástica, fibroblástica e a severidade do infiltrado inflamatório presente. Através desta análise pôde-se constatar que o fio de poliglecaprone 25 induziu reação inflamatória menos intensa, seguido pelos fios de poliglactina 910 e politetrafluoretileno, respectivamente. Tais resultados de comportamento biológico devem ser considerados quando da escolha do fio de sutura a ser empregado em cirurgias bucais.

The authors evaluated the biocompatibility of three suture materials, polyglecaprone 25, polyglactin 910 and polytetrafluorethylene, implanted into subcutaneous tissue in the dorsal region of 20 Wistar albinus rats. After periods of 2, 7, 14 and 21 days, the rats were sacrificed and the specimens were processed for routine histotechnical analysis and stained with hematoxylin and eosin. The rate of fibrosis, angioblastic and fibroblastic proliferation, and also the intensity of inflammation were observed with the optic microscope. The results showed that polyglecaprone 25 suture material induced a mild inflammatory reaction, followed by polyglactin 910 and polytetrafluorethylene, respectively. Such biological behavior must be considered during the selection of the suture material to be used in oral surgery.