Gingival inflammation and hematological parameters in children with visceral leishmaniasis: A cross-sectional study.

AIMS: This cross-sectional study aimed to assess gingival inflammation in 67 children aged 1-8 years (mean age 3.07) with visceral leishmaniasis (VL) at the time of hospitalization (D1) and 7 days after the first interview (D7) and compare the main hematological changes between the two time points. METHODS AND RESULTS: The biofilm index was verified at D1 and D7 using the Simplified Oral Hygiene Index (OHI-S) and the gingival inflammation index based on the gingival index (GI), along with hematological parameters. The mean OHI-S was 2.35 ± 0.93 at D1 and 1.47 ± 0.75 at D7. The mean GI was 0.56 ± 0.59 at D1 and 0.11 ± 0.32 at D7. The variable OHI-S at D1 could predict GI at D1, as an increase in the OHI-S value by one unit was associated with an increase in the GI D1 value by 0.36 units (p < .05). Multivariate linear regression analysis showed that none of the hematological variables were predictive of gingival inflammation at D1 and D7. CONCLUSION: Children with VL had poor oral hygiene on the first day of hospitalization. Clinically, the oral hygiene status progressed from poor at D1 to regular at D7. After 7 days the gingival bleeding scores also reduces.

Microbial Adhesion and Biofilm Formation on Bioactive Surfaces of Ti-35Nb-7Zr-5Ta Alloy Created by Anodization.

This study evaluated the microbial colonization (adhesion and biofilm) on modified surfaces of a titanium alloy, Ti-35Nb-7Zr-5Ta, anodized with Ca and P or F ions, with and without silver deposition. The chemical composition, surface topography, roughness (Ra), and surface free energy were evaluated before and after the surface modifications (anodizing). Adhesion and biofilm formation on saliva-coated discs by primary colonizing species (Streptococcus sanguinis, Streptococcus gordonii, Actinomyces naeslundii) and a periodontal pathogen (Porphyromonasgingivalis) were assessed. The surfaces of titanium alloys were modified after anodizing with volcano-shaped micropores with Ca and P or nanosized with F, both with further silver deposition. There was an increase in the Ra values after micropores formation; CaP surfaces became more hydrophilic than other surfaces, showing the highest polar component. For adhesion, no difference was detected for S. gordonii on all surfaces, and some differences were observed for the other three species. No differences were found for biofilm formation per species on all surfaces. However, S. gordonii biofilm counts on distinct surfaces were lower than S. sanguinis, A. naeslundii, and P. gingivalis on some surfaces. Therefore, anodized Ti-35Nb-7Zr-5Ta affected microbial adhesion and subsequent biofilm, but silver deposition did not hinder the colonization of these microorganisms.

Photoelasticity in Dentistry: a literature review

Introduction and Objective: Photoelasticity consists of an experimental technique of stress analysis. This technique is very used in most different areas including Dentistry. This literature review presents the several applications of photoelastic technique in Dentistry as well as its advantages and disadvantages. Literature review: Based on this method of analysis, it is possible the verification of the stress distribution and deformation in structures with complex geometry as maxilla and mandible. It can be used to evaluate the distribution of stress on several types of prosthesis as removable partial denture systems with different retention systems, conventional implant prosthesis, overdentures and Brånemark protocols. Moreover, photoelasticity can be used to assess the stress generated by various orthodontic movements, different orthodontic systems and different materials (orthodontic wires). In addition, it is used to analyze different defects of maxillectomy, splint types on traumatized tooth and post-core restoration methods. This technique can also be used to assess dental instruments such as evaluation of different designs of periodontal probe. Conclusion: The photoelastic analysis has been a technique of great importance in health area studies, more specifically in Dentistry. Based on this method of analysis, it is possible to measure the stress distribution and deformation in structures with complex geometry as maxilla and mandible.

Are new TiNbZr alloys potential substitutes of the Ti6Al4V alloy for dental applications? An electrochemical corrosion study.

The main aim of this work was to assess the electrochemical behavior of new Ti35Nb5Zr and Ti35Nb10Zr alloys in artificial saliva at 37 °C to verify if they are indicated to be used as biomaterials in dentistry as alternatives to Ti6Al4V alloys in terms of corrosion protection efficiency of the material. Electrochemical impedance spectroscopy (EIS) experiments were carried out for different periods of time (0.5-216 h) in a three-electrode cell, where the working electrode (Ti alloys) was exposed to artificial saliva at 37 °C. The near-surface region of the alloys was investigated using x-ray photoelectron spectroscopy (XPS). All alloys exhibited an increase in corrosion potential with the immersion time, indicating the growth and stabilization of the passive film. Ti35Nb5Zr and Ti6Al4V alloys had their EIS results interpreted by a double-layer circuit, while the Ti35Nb10Zr alloy was modeled by a one-layer circuit. In general, the new TiNbZr alloys showed similar behavior to that observed for the Ti6Al4V. XPS results suggest, in the case of the TiNbZr alloys, the presence of a thicker passive layer containing a lower fraction of TiO2 phase than that of Ti6Al4V. After long-term immersion, all alloys develop a calcium phosphate phase on the surface. The new TiNbZr alloys appear as potential candidates to be used as a substitute to Ti6Al4V in the manufacturing of dental implant-abutment sets.

Mechanical, physical, and chemical characterization of Ti-35Nb-5Zr and Ti-35Nb-10Zr casting alloys.

Titanium is used due its excellent properties in medical and dentistry areas. With the objective of exploiting better mechanical properties, not altering its biocompatibility, it was intended to add niobium and zirconium to the titanium, being formulated two alloys Ti-35%Nb-5%Zr (alloy 1) and Ti-35%Nb-10%Zr (alloy 2) wt% produced by an arc melting method. The chemical analysis of the samples was accomplished by X-ray fluorescence, and the microstrutural evaluation by scanning electron microscopy and X-ray diffraction. The mechanical tests were: Vickers hardness, tensile strength, mechanical cycling, and fracture analysis. The results allowed characterizing the alloy 1 as alpha + beta type and the alloy 2 as beta type. It is found that the alloy 1 presented larger hardness and smaller tensile strength than the alloy 2. The fractures, after the tensile test, were of the ductile type and, after the mechanical cycling, they were of the mixed type for both alloys.

Dureza e caracterização do Ti c.p. quando submetido a tratamento térmicos e à ação de fluoreto de sódio / Hardness and characterization of the c.p. Ti when submitted to heat treatment and to the action of sodium fluoride solution

O objetivo deste trabalho foi analisar a dureza e a caracterização metalográfica doTi c.p. quando submetido a tratamentos térmicos e à corrosão por solução de fluoretos de sódioa 1%. As amostras foram submetidas a dois tipos de tratamento térmico, têmpera e recozimento.Em seguida, foram submersas em solução de fluoreto de sódio por 30 dias e depois por mais30 dias. Entre cada etapa, foi feita a caracterização por meio de teste de dureza e microscopia óptica.No ensaio de dureza Vickers, verificou-se diferenças estatísticas entre os grupos estudados e queos tratamentos térmicos realizados elevaram a dureza do Ti c.p. por aliviar a tensão do material etorná-lo uma estrutura cristalina, fato este que deve melhorar as propriedades do material. Alémdisso, verificou-se que os grupos estudados, ao serem submetidos à ação de íons fluoreto apósos tratamentos térmicos, tiveram seus valores de dureza aumentados devido, provavelmente, aoprocesso de friabilidade. Na análise metalográfica, foram observadas diferenças entre as amostrasquando submetidas à ação dos íons fluoreto, e essa exposição à solução fluoretada danificou asuperfície desse biomaterial.

The purpose of this study was to measure the c.p. Ti hardness and to analyze thestructure of the c.p. Ti surface using an optical microscopy, when submitted to heat treatmentsand to corrosion by 1% sodium fluoride solution. The samples were submitted to two types ofheat treatment, tempering and annealing, after been submitted to sodium fluoride solution by30 days and then by more 30 days, and the characterization was made through tests of hardnessand optical microscopy technique. Statistical differences amongst the studied groups were verifiedby the Vickers hardness test, which resulted higher hardness c.p. Ti when used the heat treatments,that could be explained by relieving the mechanical stress of the material and making the crystallinestructures more defined, and this fact should improve the material properties. Besides that, it wasverified that the groups submitted to ions fluoride action, after the heat treatments, had their valuesof hardness increased, due, probably, to the heat process that increases the material friability. Inthe optical metalograph analysis, differences amongst the samples were observed when they weresubmitted to ions fluoride action, probably because the exposure of the titanium to fluoride solutionresulted damages to the surface of this important biomaterial.