Hugo Ramalho Sarmento

Elements of Implant-Supported Rehabilitation Planning in Patients With Bruxism

Abstract The rehabilitation of partial or completely edentulous patients with implant-supported prostheses has been widely used, achieving high success rates. However, many studies consider the presence of bruxism as a contraindication for this treatment modality. The purpose of this study was to revise the literature and identify risk factors in implant-supported rehabilitation planning in subjects with bruxism. Available literature was searched through Medline, with no time limit, including only studies in English. Topics discussed were etiology of bruxism and its implications on dental implants, biomechanical considerations regarding the overload on dental implants, and methods to prevent the occurrence of overloads in implant-supported prostheses. The rehabilitation of bruxers using implant-supported prostheses, using implants with adequate length and diameter, as well as proper positioning seems to be a reliable treatment, with reduced risks of failure. Bruxism control through the use of a nightguard by rigid occlusal stabilization appliance relieved in the region of implants is highly indicated. Although it is clear that implant-supported rehabilitation of patients with bruxism requires adequate planning and follow-up, well-designed randomized controlled trials are needed to provide reliable evidence on the long-term success of this treatment modality.

Novel experimental cements for use on the dentin-pulp complex

This aim of this study was to evaluate the physicochemical and biological properties of novel experimental cements (Hybrid, Paste and Resin) based on synergistic combinations of existing materials, including pH, diametral tensile strength (DTS) and cytotoxicity comparing them with mineral trioxide aggregate (MTA - Angelus®) and a glass ionomer cement (GIC) developed at our laboratory. For the physicochemical and biological tests, specimens with standard dimensions were produced. pH measurements were performed with digital pH meter at the following time intervals: 3, 24, 48 and 72 h. For the DTS test, cylindrical specimens were subjected to compressive load until fracture. The MTT assay was performed for cytotoxicity evaluation. Data were analyzed by ANOVA and Tukeys test (α=0.05). Paste group showed pH values similar to MTA, and Hybrid group presented pH values similar to GIC (p>0.05). The tested materials showed pH values ranging from alkaline to near neutrality at the evaluated times. MTA and GIC showed similar DTS values. The lowest and highest DTS values were seen in the Paste and Resin groups, respectively (p<0.05). Cell viability for MTA and experimental Hybrid, Paste and Resin groups was 49%, 93%, 90% and 86%, respectively, when compared with the control group. The photo-cured experimental resin cement showed similar or superior performance compared with the current commercial or other tested experimental materials.

Radiopacity of restorative composites by conventional radiograph and digital images with different resolutions

Purpose This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digital images with different resolutions. Materials and Methods Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using #4 sized intraoral film and digital images were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographic images. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukeys test (p<0.05), considering the material factor and then the radiographic method factor, individually. Results The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites. Conclusion The high speed mode of digital imaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

Erosion and abrasion on dental structures undergoing at-home bleaching

This review investigates erosion and abrasion in dental structures undergoing at- home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled.

Resin bond to root dentin: Influence of adhesive systems and solvent drying time

Background: Endodontically treated teeth with damaged coronal tooth structure need an additional retention to provide a durable restoration. We evaluate different adhesive systems and solvent drying time on the push-out bond strength of fiber posts luted to root dentin. Materials and Methods: For this in vitro study, the canals of 90 bovine teeth (16 mm in length) were prepared, the roots were embedded (14 mm) in acrylic resin and allocated into nine groups ( n = 10), according to the adhesive system (Multi-bottle etch-and-rinse self-curing adhesive system-MBSC/ Scotchbond Multi-Purpose; Simplified etch-and-rinse dual-curing adhesive-SLC/One-Step; Simplified etch-and-rinse light-curing adhesive-SDC/Excite DSC) and solvent drying time (control, 50 s and 110 s). The fiber posts were luted using resin cement and composite cores were made. Each set of root/post/core was submitted to mechanical cycling (10.000.000 cycles, 84 N, 4 Hz). Each root was cut into four disk-samples (1.8 mm in thickness) and submitted to push-out testing. The data (MPa) were analyzed using analysis of variance (ANOVA) (two-way) and Tukeys test (5%). Results: The factor adhesive system ( P = 0.0081) influenced the bond strength significantly (ANOVA). The MBSC groups (6.0 ± 2.2 MPa) promoted higher bond strength than SLC groups (3.7 ± 2.1 MPa) b and was similar to SDC groups (4.4 ± 3.4 MPa) a, b (Tukey). Conclusion: The solvent drying time did not affect the bond strength of fiber postluted to root dentin, regardless the adhesive solution used.

Influência de Diferentes Sistemas Adesivos na Resistência de União de Pinos de Fibra à Dentina Intrarradicular

Objetivo: Avaliar a influencia de tres sistemas adesivos na resistencia de uniao ao push-out de pinos de fibra cimentados adesivamente a dentina radicular. A hipotese foi de que a resistencia de uniao varia em funcao do tipo de sistema adesivo. Metodo: Os canais de 30 dentes bovinos unirradiculares (16mm de comprimento) foram preparados com brocas especificas (FGM) ate 12mm. 14 mm de cada raiz foi incluida em resina acrilica e divididas em 3 grupos (n=10), de acordo com o fator oadesivoo (3 niveis): Gr1-Scotchbond Multipurpose Plus (3M ESPE), Gr2- One Step (Bisco) and Gr3- Excite DSC (Ivoclar). Os sistemas adesivos foram aplicados com um microbrush, seguindo as recomendacoes do fabricante. Os pinos de fibra (White Post DC, FGM) foram cimentados com cimento resinoso dual (All-Cem, FGM). Apos, os nucleos de resina composta (Llis, FGM) foram confeccionados e cada conjunto raiz/pino/nucleo foi submetido a ciclagem mecânica (Erios, Brazil) (106ciclos, 84N, 4 Hz, inclinacao de 45o, 37oC, sob refrigeracao constante). Cada especime foi seccionado em quatro fatias (1.8mm), as quais foram submetidas ao teste push-out em maquina de ensaio universal (ServoPulser u Shimadzu) (50Kgf, 1mm/min). Os dados (MPa) foram analisados utilizando ANOVA (1-way) e Tukey test (5%). Resultados: O fator oadesivoo (p= 0,0352) influenciou significantemente a forca de uniao (ANOVA). O Gr1 (6,8±3,8 MPa)aapresentou valores de resistencia de uniao superior ao Gr2 (3,1±1,5 MPa)be semelhantes ao Gr3 (4,4±3,3)a,b. Alem disso, Gr3 e Gr2 foram semelhantes entre si (Tukey). A hipotese foi aceita. Conclusao: Baseado nos resultados concluiu-se que os sistemas adesivos com polimerizacao quimica e dual devem ser os selecionados para procedimentos de cimentacao adesiva de pinos de fibra Objective: To evaluate the influence of three adhesive systems on the bond strength of fiber post luted to root dentine. The hypothesis was that the bond strength is influenced by the adhesive system. Method: The canals of thirty single-root bovine roots (16mm in length) were prepared using the preparation drill (FGM) until 12mm. 14 mm of each root was embedded with acrylic resin and the specimens were allocated into three groups (n=10), considering the factor oadhesiveo (3 levels): Gr1- Scotchbond Multipurpose Plus (3M ESPE), Gr2- One Step (Bisco) and Gr3- Excite DSC (Ivoclar Vivadent). The adhesive systems were applied using a microbrush, according to the manufactureAEs recommendations. The fiber posts (White Post DC, FGM) were luted with dual resin cement (All-Cem,FGM). After, the cores with composite resin (Llis, FGM) were made and each set of root/post/core was submitted to the mechanical cycling (Erios, Brazil) (106cycles, 84N, 4 Hz, inclination of 45o, 37oC, water). Each specimen was cut in 4 samples (1.8mm in thickness), which were submitted to the push-out test in a universal testing machine (ServoPulser u Shimadzu) (50Kgf, 1mm/min). The data (MPa) were analyzed using ANOVA (1-way) and Tukey test (5%). Results: The factor oadhesiveo (P=0.00352) influenced the bond strength significantly (ANOVA). Gr1 (6.8±3.8 MPa)apresented higher bond strength values than Gr2 (3.1±1.5 MPa)band similar to Gr3 (4.4±3.3)a,b. Moreover, Gr3 and Gr2 were similar between them (Tukey). The hypothesis was accepted. Conclusion: Based on the results it was concluded that chemical and dual polymerization adhesive system should be used for the adhesive luting fiber post procedures

Influência de Protocolos de Jateamento na Rugosidade da Superfície de uma Cerâmica de Zircônia Tetragonal Parcialmente Estabilizada por Ítria

Objetivo: Avaliar a influencia de diferentes protocolos de jateamento na rugosidade superficial de uma cerâmica policristalina de zirconia tetragonal estabilizada com itria(Y-TZP), assim como a topografia superficial da cerâmica apos o tratamento.Metodo: A partir de dois blocos cerâmicos (LAVA, 3M ESPE), obtiveramse 54 especimes (7,5x4x7,5mm), sendo estes regularizados com lixas dAEagua em granulacao fina e sinterizados em forno especifico do sistema cerâmico. Em seguida, os corpos de prova foram incluidos em resina acrilica e as superficies a serem tratadas foram lixadas em politriz com lixas dAEagua em granulacao decrescente (600 a 1.200), associadas a pastas de polimento de 10µm, 3µm e silica coloidal em disco de feltro, sendo distribuidas aleatoriamente em 9 grupos, de acordo com os fatores oparticulao e opressaoo(n=6): Gr1- controle; Gr2-Al2O3(50µm)/2,5bar; Gr3- Al2O3(110µm)/2,5 bar; Gr4-SiO2(30µm)/2,5bar; Gr5- SiO2(30µm)/2,5bar; Gr6- Al2O3(50µm)/3,5bar; Gr7- Al2O3(110µm)/3,5bar; Gr8- SiO2(30µm)/3,5bar; Gr9-SiO2(30µm)/3,5bar. Apos os tratamentos, a rugosidade das superficies foi analisada por meio de um perfilometro optico digital e a morfologia, por meio de Microscopia Eletronica de Varredura (MEV). Os dados (µm) obtidos foram submetidos a analise estatistica por meio do teste de Dunnett (5%), ANOVA (2 fatores) e teste de Tukey (5%).Resultados: O tipo de particula (p=0,0001) e a pressao (p=0,0001) utilizada no jateamento influenciaram os valores de rugosidade entre os grupos experimentais (ANOVA). Os valores medios de rugosidade (µm) obtidos para os grupos experimentais (Gr2 a Gr9) foram, respectivamente: 0,37D; 0,56BC; 0,46BC; 0,48CD; 0,59BC; 0,82A; 0,53BCD; 0,67AB. A analise em MEV revelou que o Al2O3, independente do tamanho das particulas e da pressao utilizada, danificou a superficie dos especimes, uma vez que foram observados danos superficiais na cerâmica, na forma de ranhuras e de lascamentos.Conclusao: O jateamento com Al2O3(110µm)/3,5bar foi o tratamento que promoveu a maior rugosidade nas superficies cerâmicas, embora nao signifique que este protocolo promova melhor uniao cerâmicacimento em relacao aos demais tipos de jateamento (AU) Objective: To evaluate the influence of different air abrasion protocols on the surface roughness of an yttria-stabilized polycrystalline tetragonal zirconia) (Y-TZP) ceramic, as well as the surface topography of the ceramic after the treatment. Method: Fifty-four specimens (7.5x4x7.5mm) obtained from two ceramic blocks (LAVA, 3M ESPE) were flattened with fine-grit sandpaper and subjected to sintering in the ceramic systemAEs specific firing oven. Next, the specimens were embedded in acrylic resin and the surfaces to be treated were polished in a polishing machine using sandpapers of decreasing abrasion (600- to 1,200-grit) followed by felt discs with 10µm and 3µm polishing pastes and colloidal silica. The specimens were then randomly assigned to 9 groups, according to factors oparticleo and opressureo(n=6): Gr1- control; Gr2-Al2O3(50µm)/2.5 bar; Gr3- Al2O3(110µm)/2.5 bar; Gr4- SiO2(30µm)/2.5 bar; Gr5- SiO2(30µm)/2.5 bar; Gr6- Al2O3(50µm)/3.5 bar; Gr7-Al2O3(110µm)/3.5 bar; Gr8- SiO2(30µm)/3.5 bar; Gr9- SiO2(30µm)/3.5 bar. After treatments, surface roughness was analyzed by a digital optical profilometer and the morphology was examined by scanning electron microscopy (SEM). Data (µm) were subjected to statistical analysis by DunnettAEs test (5%), two-way ANOVA and TukeyAEs test (5%).Results: The type of particle (p=0.0001) and the pressure (p=0.0001) used in the air abrasion protocols influenced the surface roughness values among the experimental groups (ANOVA). The mean surface roughness values (µm) obtained for the experimental groups (Gr2 to Gr9) were, respectively: 0.37D; 0.56BC; 0.46BC; 0.48CD; 0.59BC; 0.82A; 0.53BCD; 0.67AB. The SEM analysis revealed that Al2O3, regardless of the particle size and pressure used, caused damage to the surface of the specimens, as it produced superficial damages on the ceramic, in the form of grooves and cracks. Conclusion: Al2O3 (110 µm/3.5 bar) air abrasion promoted the highest surface roughness on the ceramics, but it does not mean that this protocol promotes better ceramic-cement union compared to the other air abrasion protocols (AU)