Oral microbiota in human health and disease: A perspective.

The evolution of medical knowledge about oral microbiota has increased awareness of its important role for the entire human body health. A wide range of microbial species colonizing the oral cavity interact both with each other and with their host through complex pathways. Usually, these interactions lead to a harmonious coexistence (i.e. eubiosis). However, several factors - including diet, poor oral hygiene, tobacco smoking, and certain medications, among others - can disrupt this weak homeostatic balance (i.e. dysbiosis) with potential implications on both oral (i.e. development of caries and periodontal disease) and systemic health. This article is thus aimed at providing an overview on the importance of oral microbiota in mediating several physiological and pathological conditions affecting human health. In this context, strategies based on oral hygiene and diet as well as the role of probiotics supplementation are discussed.

Influence of an Innovative Anti-Corrosive Solution on Resistance of Endodontic NiTi Rotary Instruments: A Preliminary Study.

OBJECTIVE: To evaluate the effects of deionised water, blood, phosphate-buffered saline (PBS) and a new anti-corrosive solution based on methoxy propyl amine (MOPA) on the cyclic fatigue resistance of endodontic NiTi rotary instruments under in vitro conditions. METHODS: Forty ProTaper F1 files were provided and divided to four groups (n=10). Samples were first autoclaved and then stored in deionised water, blood, PBS or MOPA for 24 hours. Cyclic fatigue was tested with a custom-made stainless-steel block including artificial canals (curvature angle=30 degree, radius of curvature=5 mm). After immersion in test solutions, samples were rotated 300 rpm until fracture occurred. The number of cycles to failure (NCF) was calculated using recorded fracture time. RESULTS: Data were analysed by the Kolmogorov-Smirnov, Levene, ANOVA and Scheffe statistical tests. Samples in blood group showed the lowest and samples in MOPA group showed the highest NCF values. Significant difference was observed between groups (P=0.001). NCF value of PBS group was significantly more than the NCF values of samples in blood and deionised water groups (P<0.05). CONCLUSION: The tested novel anti-corrosive solution significantly increased the fracture resistance of the endodontic NiTi rotary instruments by reducing the cyclic fatigue. In contrast, blood and deionised water caused more corrosion and resulted in earlier file fracture.

The effect of pH on solubility of nano-modified endodontic cements.

AIMS: To evaluate the effect of storage pH on solubility of white mineral trioxide aggregate (WMTA), bioaggregate (BA), and nano WMTA cements. MATERIALS AND METHODS: Forty-eight moulds randomly allocated into three groups of pH 4.4 (group A), 7.4 (group B), and 10.4 (group C); and one empty as control in each group. Each group was further divided into three subgroups according to the material studied; WMTA, BA, and nano WMTA. The specimens in subgroup A were soaked in butyric acid buffered with synthetic tissue fluid (STF) (pH 4.4), while the samples in subgroups B (pH 7.4) and C (pH 10.4) buffered in potassium hydroxide for 24 h and then the loss of cement was determined. A two-way analysis of variance (ANOVA) and Tukey post-hoc statistical tests were used to detect any statistically significant differences among the groups/subgroups. RESULTS: Statistical analysis has showed the highest solubility in acidic pH for all tested materials. Nano WMTA samples in pH = 10.4 had the lowest and BA samples in pH = 4.4 showed the highest cement loss. CONCLUSION: The solubility of all tested cements can be jeopardized in acidic environment which might affect on their sealing characteristic in clinical scenario. However, nano WMTA cement due to its small size particles and different additives was capable of producing lower porosity in set material, which resulted in showing more resistance in acidic environment.

A comparison of three resin bonding agents to primary tooth dentin / Uma comparação de tres agentes resinosos em dentina de dentição primária

This study determined the shear bond strength of resin composites to primary dentin using three dentin adhesives and the presence or absence of a hybrid zone. The buccal and lingual surfaces of 40 recently extracted noncarious primary teeth were ground flat with SiC paper ending with the 600 grit. The teeth were divided at randomly into eight groups of five teeth (10 surfaces) each: 1) Unetched dentin, dry dentin, All-Bond 2/Bis-Fil P; 2) Unetched dentin, moist dentin, All-Bond 2/Bis-Fil P; 3) Dentin etched for 15 sec with 10 per cent phosphoric acid, dry dentin, All-Bond 2/Bis-Fil P; 4) Dentin etched for 15 sec with 10 per cent phosphoric acid moist dentin, All-Bond 2/Bis-Fil P; 5) Dentin etched with 10 per cent maleic acid for 15 sec, dry dentin, Scotchbond Multi-Purpose/Z100; 6) Dentin etched with 10 per cent maleic acid for 15 sec, moist dentin, Scotchbond Multi-Purpose/Z100; 7) Dentin etched with 10 citric acid/ 3 per cent ferric chloride, dry dentin, Amalgambond Plus/Z100; 8) Dentin etched with 10 citric acid/3 per cent ferric chloride, moist dentin, Amalgambond Plus/Z100...

Amálgama dentário, mercúrio e sua toxidade / Dental amalgam, mercury and its toxicity

A liberaçäo do mercúrio pela restauraçäo de amálgama é menor do que as quantidades ingeridas na dieta. Níveis de mercúrio nos dentistas säo mais altos do que na populaçäo em geral, mas dentistas säo saudáveis e näo tem doenças raras ou mortes prematuras. Amálgamas säo anti-estéticos e seräo trocados por restauraçöes estéticas, mas näo vamos trocar amálgama prematuramente e por razöes erradas