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

Dental caries and bacterial load in saliva and dental biofilm of type 1 diabetics on continuous subcutaneous insulin infusion

Abstract Objectives Since most of the studies evaluates diabetics on multiple daily injections therapy and continuous subcutaneous insulin infusion may help gain better metabolic control and prevent complications, the objective of this study was to evaluate the prevalence of dental caries, the unstimulated salivary flow rate and the total bacteria load, Streptococcus spp. levels and Lactobacillus spp. levels in saliva and supragingival dental biofilm of type 1 diabetics on insulin pump. Material and Methods Sixty patients with type 1 diabetes on insulin pump and 60 nondiabetic individuals were included. The dental caries evaluation was performed using ICDAS and the oral hygiene was assessed according to Greene and Vermillion Simplified Oral Hygiene Index. Unstimulated saliva and supragingival dental biofilm were collected. Total bacteria, Streptococcus spp. and Lactobacillus spp. was quantified by qPCR. Results Patients with type 1 diabetes had a higher prevalence of dental caries and filled and missing teeth when compared with the control group. These patients were associated with more risk factors for the development of dental caries, namely a lower unstimulated salivary flow rate and a higher bacterial load in saliva and dental biofilm. Conclusion Some risk factors related to dental caries were associated with type 1 diabetics. An early diagnosis combined with the evaluation of the risk profile of the diabetic patient is imperative, allowing the dental caries to be analyzed through a perspective of prevention and the patient to be integrated into an individualized oral health program.

Effects on gastric mucosa induced by dental bleaching – an experimental study with 6% hydrogen peroxide in rats

The value of aesthetic dentistry has precipitated several developments in the investigation of dental materials related to this field. The free marketing of these products is a problem and it is subject to various interpretations regarding its legality. There are several techniques for tooth whitening, the most used one being the external bleaching. It is the later version of such technique that poses the greatest danger of ingesting the product. The present study analysed the systemic effect of these products when they are swallowed.Objective This experimental study aimed to observe the effects of a tooth whitening product, whose active agent is 6% hydrogen peroxide, on the gastric mucosa of healthy and non-tumour gastric pathology animals.Material and Methods Fifty Wistar-Han rats were used and then distributed into 5 groups, one for control and four test groups in which the bleaching product was administered in animals with and without non-tumour gastric pathology (induced by the administration of 1 sample of 50% ethanol and 5% of drinking water during 6 days) at different times of study by gavage. There was a decrease in body weight in animals of groups handled during the study period, which was most pronounced in IV and VA groups. Changes in spleen weight relative to body weight revealed no statistically significant changes. An analysis of the frequency was performed on the results of macroscopic observation of the gastric mucosa.Results The gastric mucosa revealed lesions in all manipulated groups, being more frequent in groups III and IV. It appears that there is a synergism when using hydrogen peroxide and 50% ethanol in the same group.Conclusion Therefore, it seems that there are some signs of toxicity 3 to 4 days after administration of 6% hydrogen peroxide. The prescription of these therapies must be controlled by the clinician and the risks must be minimized.

The effect of Emdogain gel on periodontal regeneration in autogenous transplanted dog's teeth.

Aim: The aim of this study was to assess the enamel matrix derivative (EMD) as biomaterial used in autogenous tooth transplantation. Material and Methods: The study consisted of 3 beagle dogs, 5 months old, in which six incisors and six premolars were transplanted to mechanically prepared recipient alveolar sockets. One group of teeth was transplanted to a recipient bed, with EMD in the root surface. The second groups of teeth were transplanted using saline solution in the root surface. Every week, clinical examinations were done. Nine weeks later, the animals were killed and the specimens decalcified and prepared for histological and imunohistochemical analysis. Periodontal healing was evaluated by undertaking histomorphometric investigation and analyzed using the Mann- Whitney test (P = 0.05). Results: In both groups, all the transplanted teeth survived. Between the experimental groups, there was statistically significant difference in the complete healing (P = 0.004). There was statistically significant difference between the treatment group in the occurrence of inflammatory root resorption (P = 0.015) and the occurrence of replacement root resorption (P = 0.041). Conclusions: Emdogain gel used on the surface of transplanted teeth improves the occurrence of complete healing and reduces root resorption.

Effect of calcium hydroxide as intracanal medication on the apical sealing ability of mineral trioxide aggregate (MTA): an in vitro apexification model / Efeito da medicação intracanal de hidróxido de cálcio na capacidade seladora do mineral trióxido agregado (MTA): um modelo de apicificação in vitro

Objective - To evaluate the effect of calcium hydroxide premedication on the apical seal of White MTA, placed as an apical barrier in permanent teeth with simulated immature apices. Furthermore, we intended to compare potential changes, under the influence of calcium hydroxide, in the apical seal of MTA over time. Methods - Thirty-four single-rooted extracted teeth were prepared in order to simulate a divergent open apex. Two experimental groups of 10 teeth were created: group 1 (G1) and group 2 (G2) with and without calcium hydroxide intracanal medication previous to the placement of MTA apical plug. Two control groups, positive and negative, each with 7 teeth were created. On the 7th and on the 28th day after placement of the MTA apical plug, the apices of the teeth were submersed in a solution of sodium pertechnetate (99mTcO4Na) for 3 hours. The radioactivity was measured using a gamma camera. Results - Results revealed statistically significant differences between the 2 control groups and the 2 experimental groups with respect to the microleakage. Within the experimental groups no statistically significant differences were found; nor between the two observed periods. Conclusion - Based on the results obtained in this study, it was concluded that intracanal medication with calcium hydroxide did not affect the sealing ability of WMTA, placed as an apical plug, neither on the 7th, nor on the 28th day.

Objetivo - Avaliar o efeito do hidróxido de cálcio como medicação intracanal, no selamento apical do MTA branco, colocado como uma barreira apical em dentes permanentes com ápices imaturos simulados. Métodos - Trinta e quatro dentes unirradiculares extraídos foram preparados para simular um ápice aberto divergente. Foram separados em dois grupos experimentais (n=10): G1 e G2 com e sem medicação intracanal de hidróxido de cálcio antes da colocação do tampão apical com o MTA e dois grupos controle, positivos e negativos (n=7 em cada). Em 7 e 28 dias após a colocação do tampão apical de MTA, os ápices dos espécimes foram submersos em uma solução de pertecnetato de sódio (99mTcO4Na) por 3 horas. A radioatividade foi medida usando uma câmara gama. Resultados - Os resultados revelaram diferenças estatisticamente significativas entre os grupos controle e os grupos experimentais com relação a microinfiltração. Não houve diferença entre os grupos experimentais nos dois períodos. Conclusão - Com base nos resultados obtidos neste estudo, concluiu-se que a medicação intracanal com hidróxido de cálcio não influenciou na capacidade seladora do MTA.

Limas endodônticas: esterilizar ou descartar

Objetivo: o objetivo desse trabalho foi comparar, qualitativa e quantitativamente, a presença de matéria orgânica em limas endodônticas depois de utilizadas, descontaminadas e esterilizadas. Métodos: foram usadas 30 limas tipo K #30, das quais 5 serviram como grupo controle positivo e 5 como negativo. Instrumentaram-se 10 molares suínos pela técnica Crown-Down, inserindo uma lima por canal num total de 25 limas. As limas do grupo 1 (n=10) foram esterilizadas em autoclave. As limas do grupo 2 (n=10) foram colocadas em banho de ultrassom com solução enzimática e posteriormente esterilizadas em autoclave. As do grupo 3 (n=5) foram utilizadas, mas não foram esterilizadas; e as do grupo 4(n=5) não foram utilizadas nem esterilizadas. As limas experimentais e de controle foram posteriormente coradas com solução de Van Gieson, observadas ao microscópio óptico e atribuído um valor representativo da quantidade de matéria orgânica ainda existente na lima, de acordo com uma escala previamente estabelecida. Essa quantificação foi realizada nos terços apical, médio e cervical da parte ativa de cada lima, e foram elaboradas tabelas comparativas entre os diferentes grupos. Resultados:os resultados demonstraram que ambos os grupos experimentais apresentaram resultados significativamente inferiores aos das limas do grupo controle positivo.Conclusão: comparando-se os grupos experimentais,as limas imersas em banho de ultrassom com solução enzimática apresentaram valores inferiores aos daquelas que não foram submetidas a esse procedimento.