Background/Aim The use of custom‐fitted mouthguards can effectively prevent dentoalveolar trauma during sports practice. The aims of this study were to (1) Evaluate the elastic modulus of different EVA commercial brands used for custom‐fitted mouthguards, and (2) Evaluate whether the different EVA brands can influence the stress and strain generated during an impact simulated by three‐dimensional finite element analysis. Methods The elastic modulus of five EVA commercial brands (Essence®, Bio‐Art®, Proform®, PolyShok®, and Erkodent®) were calculated through uniaxial tensile tests. The obtained values were evaluated statistically by Kruskal–Wallis and Dunn's test. A three‐dimensional model of the anterior maxilla was created using the Rhinoceros 5.0. A 3 mm custom‐fitted mouthguard was simulated. The three‐dimensional volumetric mesh was generated using the Patran software (MSC.Software) with isoparametrics, 4‐noded tetrahedral elements, and exported to Marc/Mentat (MSC.Software) as element number 134. A non‐linear dynamic impact analysis was performed in which a rigid object struck the central incisor at a speed of 5 m/s. The stresses were evaluated by the modified von Mises criteria, and the strains were also recorded. Results Statistically significant differences were observed for elastic modulus values (p < .001). Median values and the results of the Dunn's test were Essence® (38.1 A), Bio‐Art® (34.9 AB), Proform® (20.8 BC), PolyShok® (17.4 CD), and Erkodent® (15.0 D) (different capital letters mean statistical differences among the groups). Stresses and strains generated in the model with mouthguards were significantly lower than the model without a mouthguard regardless of the commercial brand. There was no significant difference in the stress and strain on the enamel and dentin with the different EVA brands. The shock absorption ability was high for all the brands (more than 80%). Conclusion The custom‐fitted mouthguards, independently of the commercial brand, reduced stresses and strains during the impact.

Background/Aim Maxillary canines have a high incidence of impaction which may be associated with unexpected damage during maxillofacial trauma. The aim of this study was to evaluate how an impacted canine could influence the stress distribution in the dentoalveolar complex during a simulated impact before and after surgical removal plus the protective effect offered by a mouthguard. Materials and Methods Cross‐sectional finite element models of the central incisor and support structures of a patient with an impacted canine in a transverse position were made using ImageJ and Marc/Mentat software. The following impact conditions were simulated: (a) incisor with impacted canine; (b) incisor with surgical socket after impacted canine extraction; and (c) incisor after bone healing. The impacts were also simulated with a 3 mm custom‐fitted ethylene vinyl acetate mouthguard. A non‐linear dynamic impact finite element analysis was performed in which a rigid object hit the model at 1 m/s. Maximum and minimum principal stresses as well as von Mises stresses were analyzed. Results Higher values of compressive and tensile stresses occurred on the cortical bone in the models after impacted canine extraction. The highest stress concentrations in the enamel and dentin structures were observed after bone healing. The mouthguard reduced the stress in the alveolar bone and dental structures. Conclusions Use of mouthguards during impact reduced the compressive and tensile stresses in the alveolar bone, mainly in the fragile regions of the impacted canine or surgical socket.

Background/Aim Dentoalveolar trauma has a high incidence in different age groups, including the extremes, children, and older people. Mouth aging leads to some changes, one of them being the pulp volume reduction. The aim of this study was to evaluate the influence of different pulp cavity volumes and the impact direction on the stress and strain distribution of a maxillary central incisor. Material and Methods Twenty cone beam computed tomography sets of images were selected and the pulp cavity volume was measured by ITK‐SNAP software. The mean pulp cavity volume for age group of 10‐ to 12‐year‐olds was calculated to obtain the largest one. Subsequent reductions (25%, 50%, 75% and 100%) in the pulp volume values were made to simulate the aging process. The maxilla anterior segment was modeled in the Rhinoceros 5.0 software. The three‐dimensional volumetric mesh was generated using the Patran software (MSC. Software), with isoparametrics, 4‐noded tetrahedral elements, and exported to Marc/Mentat (MSC. Software) as element number 134. A non‐linear dynamic impact analysis was performed in which a steel ball reached the central incisor at a speed of 5 m/s in the horizontal or vertical direction. The stresses were evaluated by modified von Mises stresses. The strains and the total displacement were also recorded. Results The pulp volume mean value for the age group of 10‐ to 12‐year‐olds was 65.05 mm3. Stress concentrations were slightly different for the different pulp volumes. Impact directions resulted in different stress distribution. Higher stress values were present with the horizontal impact (range between 25.18 MPa and 24.08 MPa for enamel and 38.89 MPa and 37.03 for dentin) when compared to vertical impact (range between 15.30 MPa and 14.58 for enamel and 24.77 to 22.03 MPa for dentin). Total displacement was different for the two impact directions and higher for the horizontal impact. Conclusion Pulp volume did not significantly affect the stress, strain, and total displacement during the impact but the impact direction did affect the evaluated parameters during impact.

The aim of the study was to evaluate the stress distribution in the ceramic veneers in a full prosthetic crown with different framework after the sintering and cooling cycle through the thermal analysis by three-dimensional finite element analysis. Using images from a computerized microtomography of a central incisor, an anterior crown was constructed. The models were composed of 2mm thickness ceramics (feldspathic ceramics) and 0.4mm thickness frameworks (zirconia, alumina, lithium-disilicate, or metal). Ansys Workbench finite element software was used for analysis and mesh generation through a 5% convergence. The thermal loading was performed in 2 stages simulating the heating and cooling of the ceramic veneer sintering cycle: stage 1 -403 to 750 degrees C; stage 2 -from 750 to 25 degrees C. The von Mises equivalent strain(σvM) was used for the quantitative and qualitative evaluation of the framework. The maximum (σmax) and minimum (σmin) stresses were used to evaluate the ceramic veneer and zirconia, alumina, and lithium-disilicate frameworks. The highest values of compressive stress (294,58 MPa) were found in the ceramic veneer in the models with alumina framework, followed by models with zirconia (253,65 MPa), palladium silver (239,74 MPa), and lithium disilicate (205,43MPa). The tensile stresses followed the same behavior presenting the highest values in the alumina prostheses (Al: 93,977

This study evaluated the optical method for measuring free total shrinkage using a Digital Single Lens Reflex (DSLR) camera. Eight composites were evaluated, conventional, bulk fill and low-shrinkage: Z100 (3M Oral Care), Gradia Direct Anterior (GC corporation), Spectra Smart (Dentsply), Filtek Z350 XT (3M Oral Care), Aura Bulk Fill (SDI), Vittra APS (FGM), Opus Bulk Fill APS (FGM), and Beautifil II LS (Shofu Inc.). The samples (6 mm diameter and 1.5 mm thick, n = 10) were placed on a polyvinylsiloxane impression material. An image of the uncured sample was captured using a DSLR camera with 105 mm macro lens and a ring flash. Samples were light cured with a 700 mW/cm 2 LED light-cure unit for 40s. Post-polymerization images were captured at 2, 10 and 60 min. Projected circumferential areas of the specimens were drawn using the ImageJ software. Volumetric total shrinkage was calculated from the ratio of the areas obtained from pre-and post-curing. Results were analyzed using One-way ANOVA (α = 0.05) and Tukey test. Volumetric total shrinkage values were significantly different among the composite materials (p < .001). The volumetric shrinkage (%) mean and results of Tukey test at 60 min were: Z100: 3.45±0.30 (A);

The aim of this study was to evaluate dentin morphology after ozone gas and sodium ascorbate application by the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) images. Material and methods: Seven freshly extracted human third molars were sectioned perpendicularly to the tooth long axis, 3mm above the cementoenamel junction and other section above the first. Dentin slices were obtained, 2 mm thickness, then the slices were sectioned vertically and horizontally into four equal parts, resulting in 28 samples. These were divided in 4 groups (n=7): (G1) phosphoric acid – control; (G2) ozone + phosphoric acid; (G3) phosphoric acid + ozone; and (G4) ozone + sodium ascorbate + phosphoric acid. Dentin morphology of six samples of each groupwas evaluated by SEM and one by AFM. Results: In Groups 2 and 4 there was a change in the effectiveness of acid etching in terms of removing the smear layer. In Group 3 there was a change in the dentin microstructure, which can be a harmful factor regarding the bond strength of adhesive agents. Conclusion: After the qualitative analysis, the application sequences of ozone, phosphoric acid etching and sodium ascorbate application generated differences in the dentinmorphology by SEM and AFM. Sodium ascorbate decreased the ozone effect before the acid etching but did not eliminate it.

Objetivo: Analisar e discutir, por meio de uma revisão crítica da literatura, o comportamento clínico dos sistemas adesivos odontológicos “universal” ou “multimodo”. Métodos: A pesquisa bibliográfica foi restrita às bases de dados eletrônicas: MEDLINE e SciELO, utilizando os seguintes filtros: data de publicação [2014-2019], língua [portuguesa e/ou inglesa], descritores e suas combinações: “Universal adhesive”; “Multimode adhesive”; “Adesivos e Universal”; “Adesivos dentinários e Universal”; “Adesivos dentários e Universal”. Os seguintes critérios de inclusão foram adotados: estudos clínicos, dentição permanente, modos de aplicação, restaurações diretas e resinas compostas. Resultados: Dos 317 artigos identificados, 18 destes foram incluídos na análise sendo que o período de acompanhamento clínico variou entre 6 semanas e 36 meses. Conclusão: Considerando os estudos analisados de curto período de acompanhamento clínico, pode-se afirmar que os sistemas adesivos universais: (1) podem ser utilizados em dentes permanentes, a serem restaurados utilizando resina composta; (2) não devem ser aplicados sobre exposições pulpares diretas; (3) devem ser aplicados preferencialmente nos casos clínicos de procedimentos restauradores de Lesões Cervicais não Cariosas no modo Condicionamento Ácido Total ou Condicionamento Seletivo em Esmalte e no modo Condicionamento Seletivo em Esmalte nos casos de lesões cariosas.

Objetivo: Realizar, durante siete años ininterrumpidos, un control y seguimiento de las fuentes de luz disponibles en las clínicas odontológicas de pre graado de una Institución de Enseñanza Superior Pública Brasileña. Material y métodos: Durante el período comprendido entre 2011-2017 se evaluó el control de calidad de las fuentes de luz de la Facultad de Odontología de la Universidad Federal de Goiás a través del análisis de su estado de conservación y de su densidad de potencia (mW/cm2). Los datos obtenidos se sometieron a un análisis estadístico descritpivo y a las pruebas de Levene, Shapiro-Wilk, Kruskal-Wallis, Dunn y Chi-cuadrado (P<0,05). Resultados: No se observaron diferencias estadísticas significativas del estado de conservación de las fuentes de luz entre los años 2012, 2016 y 2017 (p>0,05). Sí se observaron diferencias estadísticas significativas entre los valores de densidad de potência entre dichos años (p<0,0001). En las comparaciones por pares, los valores de densidad de potencia para los años 2011 (p<0,01) y 2012 (p<0,05) fueron estadísticamente diferentes de los años 2015, 2016 y 2017. Conclusiones: Comparativamente se observó una mejora sustancial del estado de conservación de las fuentes de luz en los cuatro años iniciales de evaluaciones, con una disminución en el quinto año y una estabilización en los dos últimos años. Durante los siete años de estudio de la densidad de potencia de las fuentes de luz se observó en un aumento gradual de la misma con una estabilización de los resultados a partir del quinto año de control de calidad.