Avaliação in vitro da influência de cimentos endodônticos na resistência de união sobre estrutura dentinária da câmara pulpar de dentes restaurados imediatamente e mediatamente após obturação / In vitro evaluation of the influence of endodontic cements on bond strength on the dentin structure of the pulp chamber of teeth restored immediately and immediately after filling

Este estudo teve por finalidade avaliar a influência dos cimentos endodônticos com um protocolo de irrigação na resistência de união sobre a estrutura dentinária das paredes da câmara pulpar de dentes bovinos restaurados imediatamente e após 7 dias do tratamento endodôntico. Foram avaliados os cimentos endodônticos: Cimento à base de resina epoxy (AH Plus ­ Dentsply, DeTrey, Konstanz- Alemanha) e Cimento de óxido de zinco e eugenol (Endofill ­ Dentsply Ind.com. LTDA ­ Brasil). Para a realização das restaurações foi utilizado o sistema adesivo Single Bond 2® (3M/ESPE) e a resina composta Z 350TM (3M/ESPE). 60 faces vestibulares da câmara pulpar de dentes bovinos foram distribuídos aleatoriamente em 4 grupos experimentais (G1-AHPlus Imediato; G2-AHPlus Mediato; G3-OZE Imediato; G4-OZE Mediato) e 2 controles (G5- NaOCl + EDTA Imediato e G6-NaOCl + EDTA Mediato). O protocolo de irrigação endodôntica deu-se através da imersão dos espécimes em solução de hipoclorito de sódio a 2.5% por 30 minutos e em EDTA 17% por 3 minutos. Os cimentos testados estiveram em contato com a parede dentinária pelo tempo de presa inicial, seguido de limpeza com algodão embebido em álcool 70% por 1 minuto. Os grupos experimentais de restauração mediata foram mantidos em estufa a 37ºC por 7 dias. Após o corte e a obtenção dos palitos de +/-1,0 mm² foi aplicado o teste de microtração na Máquina de Ensaios Universal e, em seguida, observados em microscópio óptico para classificação da fratura. Os valores da resistência de união foram submetidos ao teste não-paramétrico Wilcoxon-Mann-Whitney comparando dois a dois grupos a um nível de significância de 5%. Os resultados mostraram que o grupo G5 obteve menor valor de resistência de união, com diferença estatisticamente significativa (p<0,05) para os demais. O padrão de fratura mais observado nos grupos foi a coesiva em camada híbrida. Conclui-se que a associação NaOCl + EDTA diminui a resistência de união nas restaurações imediatas e que os cimentos endodônticos não alteraram a resistência de união nos períodos testados (AU).

This study aimed to evaluate the influence of endodontic sealer with an irrigation protocol on the bond strength on the dentinal structure of the pulp chamber walls of bovine teeth restored immediately and after 7 days of endodontic treatment. Endodontic sealer were evaluated: epoxy resin-based sealer (AH Plus - Dentsply, DeTrey, Konstanz- Germany) and zinc oxide and eugenol sealer (Endofill - Dentsply Ind.com. LTDA - Brazil). To perform the restorations, the Single Bond 2® adhesive system (3M / ESPE) and the composite resin Z 350TM (3M / ESPE) were used. 60 vestibular faces of the pulp chamber of bovine teeth were randomly assigned to 4 experimental groups (G1-AHPlus Immediate; G2-AHPlus Mediato; G3-OZE Immediate; G4-OZE Mediato) and 2 controls (G5- NaOCl + EDTA Immediate and G6- NaOCl + EDTA Mediato). The endodontic irrigation protocol was carried out by immersing the specimens in 2.5% sodium hypochlorite solution for 30 minutes and in 17% EDTA for 3 minutes. The tested sealers were in contact with the dentin wall for the initial setting time, followed by cleaning with cotton soaked in 70% alcohol for 1 minute. The experimental groups of mediated restoration were kept in an oven at 37ºC for 7 days. After cutting and obtaining the +/- 1.0 mm² toothpicks, the microtensile test was applied to the Universal Testing Machine and then observed under an optical microscope to classify the fracture. The bond strength values were subjected to the non-parametric Wilcoxon-Mann-Whitney test comparing two to two groups at a significance level of 5%. The results showed that the G5 group had a lower bond strength value, with a statistically significant difference (p <0.05) for the others. The most observed fracture pattern in the groups was cohesive in a hybrid layer. It is concluded that the association NaOCl + EDTA decreases the bond strength in immediate restorations and that endodontic sealer did not change the bond strength in the tested periods (AU).

Reliability of the agar based method to assess the production of degradative enzymes in clinical isolates of Candida albicans.

The aim of this study was to establish a reproducible protocol using the methodology of hyaline zones around the colonies on specific agar plates for phospholipase and proteinase production. This was an in vitro double-blind experiment, in which the dependent variables were the enzymatic activity measurements (Pz) for the production of phospholipase (Pz-ph) and the production of secreted aspartyl proteinases (Pz-sap). Three independent variables give rise to different measurement protocols. All measurements were carried out at two different moments by four examiners (E1, E2, E3, and E4). The minimum sample size was 30 Candida albicans clinical isolates. Specific agar plates for phospholipase and SAPs production were prepared according the literature. The intra-and inter-examiner reproducibility for each protocol was estimated using the Intraclass Correlation Coefficient (ICC) and its confidence interval (95% CI). Based on the results obtained for both phospholipase and SAPs, there appears to be no consensus on the protocol chosen for each particular examiner. Measuring the colonies in triplicate may be the main factor associated with the increase in measurement accuracy and should therefore take precedence over measuring only one colony. When only one examiner is responsible for taking measurements, a standard protocol should be put in place and the statistical calibration of this researcher should be done prior to data collection. However, if two or more researchers are involved in the assessment of agar plates, our results suggest that the protocols using software to undertake plate reading is preferred.

Influence of simulated pulpal pressure on efficacy of bleaching gels.

AIM: The aim of this study was to investigate the Influence of simulated pulpal pressure on efficacy of bleaching gels. MATERIALS AND METHODS: Cylindrical enamel-dentin specimens from bovine teeth (3 mm diameter, enamel and dentin layer each 1 mm thick) were divided into 4 groups, according to the bleaching treatment: negative control (non-bleached), bleached with 10% carbamide peroxide (CP), bleached with 7.5% hydrogen peroxide (HP) and bleached with 35% hydrogen peroxide. Ten percent CP gel was applied for 8 h/day and 7.5% HP for 1 h/day, during 14 days. For 35% HP treatment, two sessions of 45 minutes each were employed. In intermediate periods specimens were stored in artificial saliva. Experimental groups (n = 19) were subdivided according to the simulation of pulpal pressure (25 mm Hg) during bleaching treatment. Initial color measurement and after bleaching treatment were assessed by spectrophotometry, using CIE L*a*b* system. The data were statistically analyzed by ANOVA and Dunnett's post-hoc tests (p < 0.05). RESULTS: There was significant difference of ΔE for all experimental groups compared to negative control group, according to Dunnett's test (p < 0.0001). There were no significant difference for total color variation (ΔE) among experimental groups (p > 0.05). CONCLUSION: It was concluded that all bleaching gels showed bleaching efficacy compared to non-bleached group and that the simulated pulpal pressure did not Influence the bleaching outcomes of the tested gels. CLINICAL SIGNIFICANCE: Although numerous in vitro studies investigating the efficacy of bleaching agents have been performed, they do not properly simulate the pulpal pressure. In order to make these studies closer to clinical conditions, it is important to reproduce these conditions in laboratory, so the results can be more reliable. This in vitro study was performed under simulated pulpal pressure, aiming to investigate its Influence on dental bleaching outcomes.

Effect of chemical activation of 10% carbamide peroxide gel in tooth bleaching.

This study aimed to evaluate the efficacy of chemical agents to increase the bleaching effectiveness of 10% carbamide peroxide. Two hundred and ninety enamel-dentin discs were prepared from bovine incisors. The color measurement was performed by a spectrophotometer using the CIE L*a*b*system. The groups were divided according to the bleaching treatment: negative control group (NC): without bleaching; positive control group (PC): bleached with 10% carbamide peroxide gel without any chemical activator; Manganese gluconate (MG); Manganese chloride (MC); Ferrous gluconate (FG); Ferric chloride (FC); and Ferrous sulphate (FS). Three different concentrations (MG, MC, FG, FC: 0.01, 0.02 and 0.03% w/w; FS: 0.001, 0.002 and 0.003% w/w) for each agent were tested. The bleaching gel was applied on the specimens for 8 h, after which they were immersed in artificial saliva for 16 h, during 14 days. Color assessments were made after 7 and 14 days. The data were analyzed by repeated measures analysis of variance and Tukey's test (5%). Generally, the test groups were unable to increase the bleaching effect (ΔE) significantly compared to the PC group. Only for ΔL, significant higher values compared to the PC group could be seen after 7 days in groups MG (0.02%), and FS (0.002 and 0.003%). The NC group showed significantly lower values than all tested groups. It was concluded that for home bleaching procedures, the addition of chemical activators did not produce a bleaching result significantly higher than the use of 10% carbamide peroxide without activation, and that the concentration of chemical activators used did not significantly influence the effectiveness of treatment.

Cisto odontogênico ortoqueratinizado x tumor odontogênico queratocístico: a importância da diferenciação histopatológica no tratamento / Orthokeratinized Odontogenic Cyst x Keratocystic Odontogenic Tumour: The Importance of Differential Histopathogenesis in the Treatment

O cisto odontogênico ortoqueratinizado (COO) e o tumor odontogênico queratocístico (TOQ) são lesões distintas, com comportamento clínico e características radiográficas semelhantes. Enquanto o COO é classificado como cisto odontogênico, o TOQ, com base na última classificação da OMS em 2005, passou a ser classificado como neoplasia odontogênica. Essa alteração realizada na classificação do TOQ baseou-se em evidências científicas que constataram uma taxa de proliferação celular dessas lesões não compatível com as lesões císticas, fato esse comprovado mediante os dos elevados índices de recidiva encontrados no TOQ. Em função das semelhanças clínicas e radiográficas, a diferenciação histológica dessas lesões torna-se preponderante para o delineamento de um plano de tratamento conservador ou agressivo. Neste trabalho, relata-se um caso de paciente com 28 anos, gênero masculino, leucoderma, com aumento de volume assintomático em mandíbula, na região dos dentes 33, 34 e 35, todos com vitalidade. Os exames de imagem revelaram lesão radiolúcida em parasínfise e corpo mandibular esquerdo. O paciente foi submetido à punção aspirativa, com resultado negativo, e à biópsia incisional. O material coletado foi enviado a um laboratório de anatomopatologia cujo laudo revelou tumor odontogênico queratocístico. Assim sendo, o paciente foi submetido à cirurgia de enucleação com curetagem marginal, evoluindo sem intercorrências no pós-operatório. O material coletado durante a enucleação foi encaminhado ao laboratório de Patologia Bucal da Faculdade de Odontologia de São José dos Campos - UNESP cujo laudo mostrou lesão cística revestida por epitélio ortoqueratinizado compatível com cisto odontogênico ortoqueratinizado, contradizendo o resultado obtido na biópsia incisional. Atualmente, o paciente encontra-se em proservação há 72 meses, sem indícios de recorrência lesional.

The orthokeratinized odontogenic cyst (OOC) and keratocystic odontogenic tumour (KCOT) are distinct lesions with similar clinical behavior and radiological features. According to the latest edition of the WHO classification, the KCOT is now classified as an odontogenic neoplasm and the OOC continuesto be classified as an odontogenic cyst. This change made in the classification of KCOT was based on scientific evidence that demonstrated that the proliferation rate of these lesions is not compatible with cystic lesions, a fact demonstrated by the high rate of recurrence found in KCOT. Due to their clinical and radiological similarities, the histological differentiation of these lesions is crucial when choosing whether to adopt a conservative or invasive plan of treatment. In this paper, we describe a 28-year-old male patient, caucasian, with asymptomatic increased volume in the mandible in the region of teeth 33, 34 and 35, all with vitality. The imaging studies revealed a radiolucent lesion in the left mandibular body and parasymphysis. The patient underwent aspiration with negative results and incisional biopsy. The material collected was sent to an anatomic pathology laboratory, and the report revealed a keratocystic odontogenic tumour. The patient therefore underwent a surgical enucleation with marginal curettage, with an unremarkable postoperative course. The material collected during the enucleation was sent to the Oral Pathology Department at the School of Dentistry, São José dos Campos - UNESP, whose report revealed a cystic lesion lined by orthokeratinizing epithelium compatible with an orthokeratinized odontogenic cyst, which was at odds with the result obtained in the incisional biopsy. The patient has been followed up for 72 months with no evidence of recurrence of the lesion.