Evaluation of periodontal indices in young adults submitted to chlorhexidine 0. 12% mouthwash: a randomized clinical trial / Avalização dos índices periodontais em adultos jovens submetidos a enxaguatório bucal a 0, 12% de clorexidina: um ensaio clínico randomizado

Introduction Gingivitis is a gingival inflammation which can often be treated with oral hygiene such as brushing, flossing, and an antiseptic mouthwash. Objective The aim of this randomized clinical trial was to clinically evaluate the effectiveness of 0.12% chlorhexidine (CHX) solution as an anti-inflammatory agent and for reducing the presence of plaque and inflammation in young adults. Material and method Thirty patients with gingivitis aged 18 to 30 years with a probing depth ≤ 3 mm and a minimum of 20 teeth in the whole mouth were selected and evaluated at baseline and 30 days after treatment. Periodontal clinical parameters were verified: plaque index (PI), gingival index (GI), Simplified Oral Hygiene Index (OHI-S), Simplified Debris Index (DI-S), and Simplified Calculus Index (CI-S) Patients were then randomly allocated into two groups: CHX Group, received chlorhexidine 0.12% labeled as solution 1, and Placebo Group, received saline solution labeled as solution 2. Both groups were included in a hygiene program and received mouthwash. Result Statistically significant differences between CHX and Placebo groups were observed for the variables PI, GI, DI-S, CI-S, and OHI-S (p<0.05 - Paired T Test) after 30 days. The CHX group presented improved GI compared to Placebo at 30 days. Chlorhexidine 0.12% was efficient in the control of periodontium inflammation. Conclusion It can be concluded that chlorhexidine as a mouthwash is efficient in improving periodontal indices in young adults, but it is still controversial whether age can influence GI and OHI-S.

Introdução A gengivite é uma inflamação gengival que geralmente pode ser tratada com higiene oral, como escovação, uso do fio dental e um anti-séptico bucal. Objetivo O objetivo deste ensaio clínico randomizado foi avaliar clinicamente a eficácia da solução de clorexidina 0,12% (CHX) como um agente antiinflamatório e na redução da presença de placa e inflamação em adultos jovens. Material e método Trinta pacientes com gengivite com idade entre 18 e 30 anos com profundidade de sondagem ≤ 3 mm com mínimo de 20 dentes em toda a boca foram selecionados e avaliados no início do estudo e 30 dias após o tratamento. Foram verificados os parâmetros clínicos periodontais: índice de placa (IP), índice gengival (GI), Índice de Higiene Oral Simplificado (IHO-S), Índice de Debris Simplificado (DI-S) e Índice de Cálculo Simplificado (IC-S). A seguir, os pacientes foram alocados aleatoriamente em dois grupos: Grupo CHX, recebeu clorexidina 0,12% previamente identificada como solução 1 e grupo placebo, recebeu solução salina identificada como solução 2. Ambos os grupos foram incluídos em programa de higiene e receberam enxaguatório bucal. Resultado Diferença estatisticamente significante entre os grupos CHX e Placebo foi observada para as variáveis ​​PI, GI, DI-S, CI-S e OHI-S (p <0,05 - Teste T Pareado) após 30 dias. O grupo CHX melhorou a resposta ao GI em comparação ao placebo em 30 dias. Clorexidina 0,12% foi eficiente no controle da inflamação do periodonto. Conclusão Pode-se concluir que a eficácia da clorexidina como enxaguatório bucal na melhora dos índices periodontais foi confirmada em adultos jovens, mas ainda é controverso que a idade pode influenciar o IG e IHO-S.

Silver nanoparticles in dental biomaterials.

Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time.

Dental enamel irradiated with a low-intensity infrared laser and photoabsorbing cream: a study of microhardness, surface, and pulp temperature.

OBJECTIVE: The aim of this study was to assess the effect of low-intensity infrared laser light (λ=810 nm, 100 mW/cm(2), 90 sec, 4.47 J/cm(2), 9 J) with or without indocyanine green cream fluorinated or not fluorinated, using Knoop surface microhardness analysis. BACKGROUND DATA: Lasers can be used as tools for the prevention of tooth enamel demineralization. METHODS: The surface and pulp temperatures of the human deciduous tooth enamel were measured. For the analysis of surface hardness, a total of 48 specimens were prepared and randomly assigned into six groups (n=8/group): C (+), which received laser light; C(-), which received no treatment; cream (IV); cream and fluoride (IVF); cream and light (IVL); and cream and fluoride and light (IVFL). The specimens were subjected to treatment before demineralizing challenge by pH cycling. To analyze the surface and pulp temperatures, the samples were divided into the following groups (n=10): C(+), IVL, and IVFL. RESULTS: The hardness analysis indicated that the groups that received irradiation had less hardness reduction following the demineralizing challenge (p<0.001), with IVFL and IVL presenting the lowest percentages of surface microhardness loss at 3.98% and 9.3%, respectively. Surface temperature analysis indicated a maximum increase of 74°C and a mean of 45.25°C and 45.95°C for the IVL and IVFL groups, respectively. Pulp temperature analysis indicated a higher mean increase of 2.40°C±0.65 in the IVL group. CONCLUSIONS: These results suggest that the combination of cream and laser light possibly promoted protein denaturation of the tooth enamel organic matrix, which possibly decreased the loss of hardness without causing pulp damage.

Influence of restorative techniques on marginal adaptation and dye penetration around Class V restorations.

The aim of this study was to observe the influence of restorative techniques on marginal adaptation and dye penetration around Class V restorations simulating abfraction lesions. Sixty mandibular premolars were divided into six groups (n = 10) using different restorative materials. Cavity preparation presented the gingival wall localized in dentin and the incisal wall in enamel. Replicas of abfraction lesions were obtained and viewed under a stereomicroscope for adaptation assessment. All teeth were subjected to thermocycling and mechanical load cycling and immersed in 0.5% methylene blue dye (pH 7.2) for four hours. The results were tabulated and submitted to Kruskal-Wallis tests, which were significant for the dentin margin with lower microleakage values for primer/Vitremer, followed by Clearfil SE Bond/Durafill VS and Clearfil SE Bond/Z100 in qualitative and quantitative methods (P < 0.05). The enamel margin had no significant difference for microleakage values for all groups. There was no statistically significant difference among the substrates for marginal adaptation. The Spearman coefficient illustrated a direct relation between enamel and dentin for microleakage evaluation (P < 0.0001). The data demonstrated no difference for marginal fit by chi-square test. It can be concluded that all groups had microleakage in different degrees, with the lowest values for resin-modified glass ionomer.

Stress distribution in the cervical region of an upper central incisor in a 3D finite element model.

The aim of this study was to evaluate the stress distribution in the cervical region of a sound upper central incisor in two clinical situations, standard and maximum masticatory forces, by means of a 3D model with the highest possible level of fidelity to the anatomic dimensions. Two models with 331,887 linear tetrahedral elements that represent a sound upper central incisor with periodontal ligament, cortical and trabecular bones were loaded at 45 masculine in relation to the tooth's long axis. All structures were considered to be homogeneous and isotropic, with the exception of the enamel (anisotropic). A standard masticatory force (100 N) was simulated on one of the models, while on the other one a maximum masticatory force was simulated (235.9 N). The software used were: PATRAN for pre- and post-processing and Nastran for processing. In the cementoenamel junction area, tensile forces reached 14.7 MPa in the 100 N model, and 40.2 MPa in the 235.9 N model, exceeding the enamel's tensile strength (16.7 MPa). The fact that the stress concentration in the amelodentinal junction exceeded the enamel's tensile strength under simulated conditions of maximum masticatory force suggests the possibility of the occurrence of non-carious cervical lesions such as abfractions.

Análise biomecânica de dentes restaurados com retentor intrarradicular fundido, com ou sem férula / Biomechanical analysis of teeth restored with cast intra-radicular retainer, with or without ferrule

Objetivo: Avaliar a influência de variações no formato da férula dada por núcleo estojado sobre as tensões desenvolvidas na raiz. Métodos: Seis modelos 3D de um segundo pré-molar superior foram confeccionados a partir das dimensões médias obtidas na literatura. Simulou-se uma carga mastigatória (291,36N) com resultante paralela ao longo eixo do dente. Em quatro modelos, variou-se o tamanho do espelho (E): 1/3 da espessura da parede radicular (E1) ou 2/3 (E2). A altura (A) do bisel foi equivalente a E1 (A1) ou a E2 (A2), ou seja: férula E1A1 e E2A2 com inclinação de 45º. Um modelo representou o dente hígido, outro modelo simulou núcleo apenas, com espelho, sem férula (E2A0). Todos os casos mantiveram a mesma restauração coronária. Todas as estruturas foram consideradas homogêneas, isotrópicas e lineares elásticas. O aumento da altura do estojo (de E2A1 para E2A2 ou de E1A1 para E1A2) provocou mudança das tensões compressivas para trativas na dentina radicular sobre o estojo. Resultados: Os melhores resultados foram obtidos pelo modelo E1A2, que minimizou as tensões trativas na dentina radicular cervical e na dentina radicular próxima ao ligamento periodontal, seguido do modelo E1A1, E2A1 e E2A2. Conclusão: Para distribuir, de melhor modo possível, a tensão na dentina radicular sobre o espelho é imprescindível que exista férula. A férula protege a dentina radicular sob o espelho (quanto mais alta, melhor) e a inclinação de 45º resulta em efeito protetor mais eficiente para a dentina sobre o espelho.

Objective: To evaluate the influence of variations in ferrule shape given by the core placed, on stresses developed in the root. Methods: Six 3D models of a maxillary second premolar were made according to the mean dimensions obtained in the literature. A masticatory load (291.36N) was simulated with result parallel to the long axis of the tooth. In four models, the size of the plate (E) was varied: 1/3 of the root wall thickness (E1) or 2/3 (E2). The height (A) of the bevel was equivalent to E1 (A1) or E2 (A2), that is: ferrule E1A1 and E2A2 with an inclination of 45º. One model represented a healthy tooth, another model simulated the core only, with plate, without ferrule (E2A0). All the cases had the same coronal restoration. All the structures were considered homogenous, isotropic and linear elastic. The increase in the height of the recess (from E2A1 to E2A2 or from E1A1 to E1A2) caused changes in the compressive sheer stresses in the root dentin over the recess. Results: The best results were obtained by model E1A2, which minimized the sheer/ stresses in the cervical root dentin and in the root dentin close to the periodontal ligament, followed by models E1A1, E2A1 and E2A2. Conclusion: To distribute the stress on the root dentin on the plate in the best possible manner, it is imperative to have the ferrule. The ferrule protects the root dentin under the plate (the higher the better) and the inclination of 45º results in a more efficient protective effect for the dentin over plate.

Stress distribution in the cervical region of an upper central incisor in a 3D finite element model

The aim of this study was to evaluate the stress distribution in the cervical region of a sound upper central incisor in two clinical situations, standard and maximum masticatory forces, by means of a 3D model with the highest possible level of fidelity to the anatomic dimensions. Two models with 331,887 linear tetrahedral elements that represent a sound upper central incisor with periodontal ligament, cortical and trabecular bones were loaded at 45º in relation to the tooth's long axis. All structures were considered to be homogeneous and isotropic, with the exception of the enamel (anisotropic). A standard masticatory force (100 N) was simulated on one of the models, while on the other one a maximum masticatory force was simulated (235.9 N). The software used were: PATRAN for pre- and post-processing and Nastran for processing. In the cementoenamel junction area, tensile forces reached 14.7 MPa in the 100 N model, and 40.2 MPa in the 235.9 N model, exceeding the enamel's tensile strength (16.7 MPa). The fact that the stress concentration in the amelodentinal junction exceeded the enamel's tensile strength under simulated conditions of maximum masticatory force suggests the possibility of the occurrence of non-carious cervical lesions such as abfractions.

Análise biomecânica de dentes restaurados com retentor intra-radicular fundido, com e sem férula / Biomechanics analysis of restored teeth with cast intra-radicular retainer, with and without ferrule

O objetivo foi avaliar a influência de variações no formato da férula dada por núcleo estojado sobre as tensões desenvolvidas na raiz em um modelo tridimensional de um segundo pré-molar superior submetido a quatro consições de carregamentos: cunha, alavanca vestibular, alavanca proximal e torção. Seis modelos foram confeccionados a partir das dimensões médias obtidas na literatura. Um deles representou o dente hígido, e outros cinco dentes restaurados com coroa e retentor intra-radicular...

The aim was to evaluate the influence of variations in the radicular ferrule format given by the casing core on stress developed in the root in a three-dimensional model of one upper second premolar submitted to four load conditions: wedge, vestibular lever, proximal lever and torsion...

Influência do material restaurador e da estrutura dental remanescente na distribuição de tensões em restaurações indiretas / The restorative material and remaining tooth influence on the strain distribution into indirect restorations

O presente estudo teve como objetivo analisar, por meio do método de elemetos finitos, a influência do preparo cavitário e do material restaurador na distribuição de tensões em restaurações do tipo inlay. Sete modelos matemáticos bidimensionais foram criados a partir de uma imagem digitalizada de um primeiro molar inferior. A análise foi feita no programa Abaqus (HKS), utilizando-se uma carga estátística de 300N distribuídas em três regiões das superfícies oclusais dos modelos. Os resultados mostraram que o compósito laboratorial (cerômero) foi o que apresentou a melhor distribuição de tensões, gerando um padrão homogêneo das mesmas.

Influência da esplintagem de restaurações protéticas fixas sobre implantes na distribuição de tensões em mandíbula edentada posterior / Influence of the splinting of implant-supported fixed restorations on stress distribution in posterior edentulous mandible

Este estudo teve como finalidade analisar a influência da esplintagem de restaurações protéticas fixas na distribuição das tensões de von Mises em dois modelos matemáticos bidimensionais obtidos pelo método de elementos finitos. O limite de proporcionalidade dos materiais e estruturas analisadas não foi alcançado nos dois modelos, de modo que nenhuma das configurações estudadas foi contra-indicada. Entretanto, os resultados sugeriram que o planejamento do tratamento deve ser adequado a condições anatômicas oclusais e biomecânicas específicas.

Análise quantitativa in vitro da obturação de canais laterais / Quantitative in vitro analysis of the filling of lateral canals

O objetivo deste trabalho foi analisar a capacidade de penetração de guta-percha e cimento nos canais laterais simulados em blocos de resina acrílica realizados com o auxílio de uma microbiota cilíndrica de 0,2 mm de diâmetro. Os canais foram obturados utilizando duas técnicas de obturação: técnica de compactação vertical de Schilder modificada utilizando o Sistema Obtura II e técnica híbrida de Tagger. A técnica utilizando o Sistema Obtura II promoveu maior preechimento de guta-percha nos três terços, enquanto que a técnica híbrida de Tagger promoveu maior preenchimento de cimento nos canais laterais cervicais e mediais

Restaurações em dentes tratados endodonticamente / Endodontically treated teeth restorations

O objetivo deste trabalho é apresentado de maneira didática, os principais conceitos envolvidos em restaurações de dentes tratados endodonticamente, retentores intra-radiculares diretos e indiretos. Novos aspectos técnico-científicos e materiais foram apresentados e discutidos, priorizando a observação e o suporte de fundamentos biomecânicos, onde características como a rigidez e o comprimento do pino podem representar destacada influência na integridade da estrutura dental remanescente