Type 1 diabetes mellitus effects on dental enamel formation revealed by microscopy and microanalysis.

BACKGROUND: Type 1 diabetes mellitus (T1DM) largely affects children, occurring therefore at the same period of deciduous and permanent teeth development. The aim of this work was to investigate birefringence and morphology of the secretory stage enamel organic extracellular matrix (EOECM), and structural and mechanical features of mature enamel from T1DM rats. METHODS: Adult Wistar rats were maintained alive for a period of 56 days after the induction of experimental T1DM with a single dose of streptozotocin (60 mg/kg). After proper euthanasia of the animals, fixed upper incisors were accurately processed, and secretory stage EOECM and mature enamel were analyzed by transmitted polarizing and bright field light microscopies (TPLM and BFLM), energy-dispersive x-ray (EDX) analysis, scanning electron microscopy (SEM), and microhardness testing. RESULTS: Bright field light microscopies and transmitted polarizing light microscopies showed slight morphological changes in the secretory stage EOECM from diabetic rats, which also did not exhibit statistically significant alterations in birefringence brightness when compared to control animals (P > .05). EDX analysis showed that T1DM induced statistically significant little increases in the amount of calcium and phosphorus in outer mature enamel (P < .01) with preservation of calcium/phosphorus ratio in that structure (P > .05). T1DM also caused important ultrastructural alterations in mature enamel as revealed by SEM and induced a statistically significant reduction of about 13.67% in its microhardness at 80 µm from dentin-enamel junction (P < .01). CONCLUSIONS: This study shows that T1DM may disturb enamel development, leading to alterations in mature enamel ultrastructure and in its mechanical features.

Bisphosphonates: Pharmacokinetics, bioavailability, mechanisms of action, clinical applications in children, and effects on tooth development.

Bisphosphonates (BPs) avidly bind to calcium crystals and inhibit osteoclastic bone resorption, making them useful for treatment of skeletal disorders such as osteoporosis, Paget's disease, osteogenesis imperfecta and metastatic bone diseases. BPs therapeutically act by causing toxic effects on osteoclasts or interfering with specific intracellular pathways in those cells. BPs that possess nitrogen in their composition are called nitrogen-containing BPs (NBPs) and include alendronate, pamidronate, risedronate, ibandronate, and zoledronate. Simple BPs or non-NBPs do not have nitrogen in their composition, include etiodronate and clodronate, and were the first to be tested in animals and clinically used. Because BPs may be administered to pregnant women or children during deciduous and permanent teeth development, it is expected that they might disturb tooth eruption and development. A review of current literature on pharmacokinetics, bioavailability, mechanisms of action, and clinical applications of BPs in children, and their effects on tooth eruption and development is presented.

Aspectos anatomohistológicos da sutura na língua com poliglecaprone 25, náilon e categute simples em ratas / Anatomohistologics aspects of the suture in the language with poliglecaprone 25, nylon and simple categute in rats

O presente estudo analisou a reação aos fios de náilon, categute simples e poliglecaprone 25 na sutura da língua das ratas. Foram utilizadas oito ratas Wistar fêmeas em cada grupo. Realizou-se, no animal sob anestesia, uma incisão (glossotomia) de 01 cm. na linha mediana da língua. No grupo do náilon 4-0, categute simples 4-0 e poliglecaprone 25 4-0, foi feita a glossorrafia com pontos separados. A reoperação seguiu o cronograma de 3, 6, 12 e 24 dias, sob a mesma técnica operatória, para fazer a glossectomia, com encaminhamento para a análise histológica. O procedimento cirúrgico foi avaliado quanto a deiscência, exsudato e edema. Os três grupos apresentaram reações semelhantes. No 3° DPO, encontrou-se o fio sem granuloma; no 6° DPO, constatou-se a existência de resto de úlcera e crosta em todos os grupos; o 12° DPO mostrou cicatriz completa no GN e incompleta nos GSC e PGP; e no 24° DPO, a cicatrização foi completa em todos os grupos. Conclui-se que todos os fios utilizados apresentaram reação inflamatória com ulcerações, sem granulomas. Aconselha-se o uso do categute simples, pois, no 6° DPO, o fio foi absorvido.