António Mata

Effects of diabetes mellitus on salivary secretion and its composition in the human

This study investigated the effects of diabetes mellitus (types I and II) on human salivary gland function compared to healthy age-matched controls. The results have shown that both type I and type II diabetic patients secrete significantly (p < 0.05) less resting and stimulated saliva compared to healthy age-matched controls (AMC). It was also found that the diabetic patients have an increased resting and stimulated salivary protein concentration compared to healthy participants. However, the secretory capacity (stimulated minus resting values) was markedly reduced compared to controls. The level of calcium (Ca2+) in the saliva of diabetic patients was significantly (p < 0.05) elevated compared to the AMC. In contrast, the levels of magnesium (Mg2+), zinc (Zn2+) and potassium (K+) in the saliva of diabetic patients were significantly (p < 0.05) reduced compared to the values obtained in AMC. These results indicate that diabetes mellitus can lead to marked dysfunction of the secretory capacity of the salivary glands. In these patients a modified fluid, organic and inorganic salivary secretion may be responsible for the increased susceptibility to oral infections and impaired wound healing described by others in the literature. (Mol Cell Biochem 261: 137–142, 2004)

Clinical efficacy of electronic apex locators: systematic review.

INTRODUCTION Apical constriction has been proposed as the most appropriate apical limit for the endodontic working length. Despite being the most used, some limitations are attributed to the radiographic method of working length determination. It lacks precision because it is based on the average position of the apical constriction. The electronic apex locators have been presented as an alternative to the odontometry performed by radiography. These devices detect the transition of the pulp to the periodontal tissue, which is anatomically very close to the apical constriction and may perform with improved accuracy. METHODS A systematic review was performed to compare the radiographic and electronic methods. Clinical studies that compared both methods were searched for on 7 electronic databases, a manual search was performed on the bibliography of articles collected on the electronic databases, and the authors were contacted to ask for references of more research not detected on the electronic and manual search. RESULTS Twenty-one articles were selected. The majority were comparative or evaluation studies, and very few clinical studies comparing both methods are available. Several methodological limitations are present on the collected articles and debated in this review. CONCLUSIONS Although the available scientific evidence base is short and at considerable risk of bias, it is still possible to conclude that the apical locator reduces the patient radiation exposure and also that the electronic method may perform better on the working length determination. At least one radiographic control should be performed to detect possible errors of the electronic devices.

Effects of gustatory stimulants of salivary secretion on salivary pH and flow in patients with Sjögren's syndrome: a randomized controlled trial.

OBJECTIVES To compare salivary pH changes and stimulation efficacy of two different gustatory stimulants of salivary secretion (GSSS) in patients with primary Sjögren syndrome. SETTING Portuguese Institute for Rheumatological Diseases. DESIGN Double-blind randomized controlled trial. SUBJECTS Eighty patients were randomized to two intervention groups. Sample size was calculated using an alpha error of 0.05 and a beta of 0.20. MATERIALS AND METHODS Participants were randomly assigned to receive a new GSSS containing a weaker malic acid, fluoride and xylitol or a traditionally citric acid-based one. Saliva collection was obtained by established methods at different times. The salivary pH of the samples was determined with a pH meter and a microelectrode. MAIN OUTCOME MEASURES Salivary pH variations and counts of subjects with pH below 4.5 for over 1 min and stimulated salivary flow were the main outcome measures. RESULTS Both GSSS significantly stimulated salivary output without significant differences between the two groups. The new gustatory stimulant of salivary secretion presented an absolute risk reduction of 52.78% [33.42-72.13 (95% CI)] when compared with the traditional one. CONCLUSIONS In Xerostomic Primary Sjögren syndrome patients, gustatory stimulants of salivary secretion based on acid mail only with fluoride and xylitol present similar salivary stimulation capacity when compared to citric acid-based ones, besides significantly reducing the number of salivary pH drops below 4.5. This could be related to a diminished risk for dental erosion and should be confirmed with further studies.

Hydrogen peroxide release kinetics into saliva from different whitening products: a double-blind, randomized clinical trial

The objective of this study is to compare salivary hydrogen peroxide (HP) release kinetics and potential toxicity of systemic exposure of four different whitening products. A double-blind, randomized controlled trial was conducted in a Portuguese dental faculty clinic. Two hundred forty volunteers were randomized to eight intervention groups. Participants were randomly assigned to receive active or placebo applications of one of four different products: Opalescence 10% PF™ (OPL), Vivastyle® 10%™ (VS10%), Vivadent Paint On Plus™ (PO+), and Trés White Supreme™ (TWS). Saliva collection was obtained by established methods at different times. The HP salivary content was determined by a photometric method. Salivary HP variations, total amount of salivary HP, and counts of subjects above the safe daily HP dose were the main outcome measures. All whitening systems significantly released HP to the saliva when compared to placebo, and all showed different release kinetics. The adaptable tray system (TWS) presented a risk increase of 37% [20–54%, 95% confidence interval] when compared to the other systems. The use of an adaptable tray whitening system with higher concentration of HP increases the toxicity potential.

Prevalence of C-shaped mandibular molars in the Portuguese population evaluated by cone-beam computed tomography.

Objective: The purpose of this study was to evaluate the prevalence of first and second C-shaped mandibular molars in a Western European population of Portuguese Caucasians. Materials and Methods: Patients having both routine panoramic radiograph and presurgical cone-beam computed tomography (CBCT) exams were selected. The CBCT examination was performed at five different axial levels and the mandibular molars were classified as C-shape according to the Fan criteria. Differences between genders, age groups, left and right side, type of tooth, and root concavity side were determined. The molars were classified as nonfused roots (NFRI–II), FRI–III, or single root with single canal (SS) groups, using the panoramic radiograph. The prevalence of C-shaped anatomy was calculated to each group. Results: A total of 1783 teeth (695 first molars and 1088 second molars) from 792 patients were included in the study. The prevalence of C-shaped configurations was 0.6% and 8.5% to mandibular first and second molars, respectively. The differences between gender, teeth, and root concavity direction were considered statistically significant (P < 0.05). The FR had a significantly higher rate of C-shapes when compared to NFR (P < 0.05). Intrarater reliability was 93.6%. Conclusions: The FR radiographic appearance may be considered a predictor of this anatomy. Second mandibular molars and females had a higher incidence ratio. Apparently, the mandibular C-shaped anatomy is more common in the population of this study than that has been previously reported for the European population.

Medicina Dentária Baseada na Evidência: Novas Opções para Velhas Práticas.

Resumo: A Medicina Dentaria Baseada na Evidencia (MDBE) consiste num algoritmo analitico interventivo cujo objectivo e permitir ao clinico responder a questoes com a certeza de ter seleccionado a melhor evidencia cientifica, de a integrar com a sua expertise e com os melhores interesses dos pacientes. E uma nova forma de pratica clinica com aplicabilidade na etiologia, diagnostico, terapeutica, prognostico e qualidade de vida que deve interessar a todos os agentes com capacidades e responsabilidades decisoras em saude. Apesar da pratica da MDBE necessitar de treino especifico pretendemos neste artigo de opiniao e divulgacao introduzir aos leitores os principais passos da pratica da MBDE, nomeadamente no que respeita a formulacao de questoes clinicas, a forma de procura e seleccao da evidencia em diversos tipos de bases de dados, da avaliacao da evidencia existente e da sua aplicacao na pratica diaria. Palavras-Chave: Medicina Dentaria Baseada na Evidencia; Educacao Medica

Ceramic-Veneered Zirconia Frameworks in Full-Arch Implant Rehabilitations: A 6-Month to 5-Year Retrospective Cohort Study.

PURPOSE This was a retrospective cohort study designed to evaluate the clinical performance of ceramic-veneered zirconia frameworks. MATERIALS AND METHODS Patients were recruited according to defined inclusion criteria. All patients were checked every 4 months from the time of definitive rehabilitation. At the end of 2013, all patients were rescheduled and rechecked for study purposes. The restorative procedures assessment was performed by previously established methods. The primary outcomes were the survival and success rates of the prosthesis. Descriptive statistics were used for the patients demographics, implant distribution, and occurrence of complications. To study the survival and success of the prostheses, a Cox Regression analysis was used with a model constructed in a forward conditional stepwise mode. Predictive variables were included in the model, and adjusted survival curves were obtained for each outcome. RESULTS From 2008 to 2013, 75 patients were rehabilitated with 92 implant-supported, screw-retained, full-arch ceramic-veneered zirconia framework rehabilitations. The range of follow-up was between 6 months and 5 years. From the 92 full implant-supported screw-retained full-arch rehabilitations, Cox regression analysis indicated that within a 5-year time frame, the probability of framework fracture, major chipping, minor chipping, or any of the former combined to occur was 17.6%, 46.5%, 69.2%, and 90.5%, respectively. CONCLUSION Results suggest zirconia as a suitable material for framework structure in implant-supported, full-arch rehabilitations. However, it experiences a high incidence of technical complications, mainly due to ceramic chipping. Further clinical studies should aim to ascertain the effects of clinical features and manufacturing procedures on the survival rates of these prostheses.

Revisões sistemáticas: O que São e para que Servem

Resumo As revisoes sistematicas constituem instrumentos valiosos para o clinico permitindo uma abordagem critica integrada do conhecimento cientifico orientada para a resposta a uma questao clinica relevante baseada na melhor evidencia cientifica disponivel. Em situacoes especificas, a informacao recolhida e seleccionada numa revisao sistematica pode ainda ser tratada estatisticamente visando a obtencao de uma estimativa de efeito comum inter-estudos, atraves de uma metaanalise. A elaboracao de uma revisao sistematica obedece a um protocolo rigoroso e padronizado, cujos aspectos serao discutidos neste artigo. Serao tambem abordadas a aplicabilidade real dos resultados de uma revisao sistematica num contexto clinico bem como os parâmetros a considerar na sua avaliacao qualitativa.

Bioactivity of novel functionally structured titanium-ceramic composites in contact with human osteoblasts: Bioactivity of functionally structured titanium-ceramic composites

The aim of this study was to analyze the osteogenic cell behavior on the surface of novel functionally graded titanium-based composites containing bioactive ceramics. Titanium grade V discs (8 × 3 mm) embedding gradual content of hydroxyapatite (TiAlV-HA) or beta-tricalcium phosphate (TiAlV-βTCP) were produced by hot-pressing technique. Titanium-ceramic composite discs and Ti grade V (control group) were placed in contact with human osteoblast culture assays. The morphology and adhesion of osteoblasts were inspected by field emission guns scanning electron microscopy (FEGSEM) while cell viability was assessed by fluorometric method. Alkaline phosphatase (ALP) activity and fluorescent microscopic analyses were used to evaluate mineralization on the test and control discs. FEGSEM images showed cells adhered to Ti6Al4V-ceramic and Ti6Al4V surfaces over a period of 24 h, and therefore, an intense proliferation of osteoblasts and spreading cells was noticed for 7 days. Cell viability increased with time on all the surfaces although TiAlV-βTCP revealed significant higher percentage of cell viability than that recorded for TiAlV-HA (p < 0.01). TiAlV-βTCP also showed the highest hydrophilic character. ALP levels increased on the Ti6Al4V-ceramic surfaces when compared to the control group. Also, a qualitative analysis of mineralization evidenced an increase in mineral content on TiAlV-HA or TiAlV-βTCP groups. Novel functionally graded composites based on Ti grade V and hydroxyapatite or βTCP showed a higher bioactivity in presence of osteoblasts than that recorded on Ti grade V. Also, such functionally graded materials can prevent risks of failures by detachment of bioactive ceramic materials during implant placement.

# 8. Nanoinfiltração no esmalte por ação do branqueamento dentário – Estudo in vitro

Objetivos: Avaliar a correlação entre a qualidade de vida oral (QVO) e sistémica (QVS) numa amostra da população portuguesa com Síndrome de Sjögren Primária (SSP). Materiais e métodos: Amostra constituída por 50 pacientes com SSP e selecionados de acordo com critérios de inclusão pré-estabelecidos. Para todos os pacientes foram obtidos, previamente, os valores de fluxos salivares, em repouso e estimulado mecanicamente (ml/min.), e índice de CPO. Foram realizadas 2 administrações de um questionário de QVO, o OHIP-14 (em que o maior resultado implica pior QVO), e de um de QVS, o SF-12 (em que o maior resultado implica melhor QVS). Foi analisada a fiabilidade com o coeficiente de correlação intraclasse (ICC), a consistência interna com o coeficiente Cronbach’s alpha e eventuais correlações entre as diferentes variáveis através da correlação de Pearson. Os resultados foram apresentados como média e 95% intervalo de confiança, com nível de significância de 0,05. Resultados: Foram obtidos bons resultados de consistência interna e de fiabilidade (Cronbach’s alpha OHIP-14 = 0,91; SF12 = 0,90; ICC OHIP-14 = [0,57:0,88]; SF-12 = [0,49:0,96]). O score do OHIP-14 correlacionou negativa e significativamente com os scores do SF-12 e fluxo salivar em repouso. Adicionalmente, o score do OHIP-14 correlacionou positivamente com o número de dentes cariados, sendo que o número de dentes perdidos obteve correlação negativa com o score físico do SF-12. Conclusões: Existe uma correlação positiva entre a QVO e QVS, em pacientes com SSP. No entanto, a realização de mais estudos é necessária.