Physical and mechanical properties of four 3D-printed resins at two different thick layers: An in vitro comparative study.

OBJECTIVES: This in vitro comparative study aimed to evaluate the physical and mechanical properties of four 3D-printed resins with two different thickness layers. METHODS: Four printed resins (VarseoSmile Crown Plus, VSC; NexDent C&B MFH, MFH; Nanolab 3D, NNL; and Resilab 3D Temp, RSL) were printed with 50 µm and 100 µm layer thickness, resulting in 80 bars measuring 25 × 2×2 mm. The specimens underwent a Raman spectroscopy for degree of conversion, confocal laser scanning microscopy for surface roughness (Sa), three-point bending test for flexural strength and elastic modulus, and a Vickers hardness test (VHN). Data was tested for normality using the Shapiro-Wilk, two-way ANOVA, and Tukey test (α = 0.05) for statistical analysis. RESULTS: The layer thickness affected all performed tests, but the elastic modulus (p < 0.001). Specimens with 100 µm showed, in general, worse results outcomes than those with 50 µm (p < 0.001). However, within the limitations of this comparative in vitro study, it could be concluded that the tested resins and layer thicknesses directly influenced physical and mechanical properties. SIGNIFICANCE: The physical and mechanical properties of three-dimensional printed restorations can be affected by the layer thickness, which can interfere with the choice of the 3D printing resin for a desired clinical outcome.

Influence of scanner, powder application, and adjustments on CAD-CAM crown misfit.

STATEMENT OF PROBLEM: The manufacturers of computer-aided design and computer-aided manufacturing (CAD-CAM) systems emphasize that new technologies can improve the marginal fit of dental crowns. However, data supporting this claim are limited. PURPOSE: The purpose of this in vitro study was to investigate the differences among the following fabrication methods on the marginal discrepancy of dental crowns: intraoral optical scanners, powder application, and adjustments of intaglio surface. MATERIAL AND METHODS: A single human premolar was fixed on a typodont and prepared to receive crowns prepared by the CEREC CAD-CAM system. Three fabrication techniques were used: digital scans using the CEREC Bluecam scanner with titanium dioxide powder (TDP), digital scans using the CEREC Omnicam scanner without TDP, and digital scans using the Omnicam scanner with TDP. Five experimental groups (n=10) were designated: Bluecam (group B), Bluecam with adjustments (group BA), Omnicam (group O), Omnicam with adjustments (group OA), and Omnicam with TDP (group OP). The specimens were scanned using microcomputed tomography to measure the vertical, horizontal, and internal fit and volumetric 3-dimensional (3D) internal fit values of each luting space. The paired t test was used to evaluate mean marginal fit change after adjustments within the same group. One-way analysis of variance and post hoc tests were used to compare groups B, O, and OP (α=.05). RESULTS: Mean vertical fit values ±standard deviations of group B=29.5 ±13.2 µm; BA=26.9 ±7.7 µm; O=149.4 ±64.4 µm; OA=49.4 ±12.7 µm; and OP=33.0 ±8.3 µm. Adjustments in the intaglio surface and TDP application statistically influenced the vertical fit of group O (P<.001). The percentage of vertical fit values <75 µm in group B=89.3%, BA=92.7%, O=31.0%, OA=73.5%, and OP=92.0%. Mean horizontal fit values for group B=56.2 ±21.5 µm; 85.8 ±44.4 µm for group BA; 77.5 ±11.8 µm for group O; 102.5 ±16.2 µm for group OA; and 91.4 ±19.4 µm for group OP. Results from group B were significantly different from those of the other test groups (P<.05). The percentages of horizontal misfit were 61.2% in group B; 73.5% in group BA; 88.1% in group O; 92.4% in group OA; and 85.0% in group OP. Volumetric 3D internal fit values in group B were 9.4 ±1.3 mm3; 10.7 ±1.0 mm3 in group BA; 11.8 ±2.1 mm3 in group O; 11.0 ±1.3 mm3 in group OA; and 9.6 ±0.9 mm3 in group OP. The overall results from groups B and OP were better than those of group O, with regard to vertical misfit and volumetric 3D internal fit. CONCLUSIONS: Different intraoral optical scanners, powder application, and internal adjustments influenced the marginal discrepancy of crowns. Crowns fabricated using the Omnicam system had significantly higher vertical discrepancy and volumetric 3D internal fit than those fabricated using the Bluecam scanner with TDP. Adjustments of the intaglio surface improved the vertical fit of crowns made using the Omnicam scanner; however, TDP application before Omnicam scanning improved the vertical fit as well as the volumetric 3D internal fit value of the luting space of crowns.

Precision Fit of Screw-Retained Implant-Supported Fixed Dental Prostheses Fabricated by CAD/CAM, Copy-Milling, and Conventional Methods.

PURPOSE: The aim of this study was to evaluate the effectiveness of fabrication methods (computer-aided design/computer-aided manufacture [CAD/CAM], copy-milling, and conventional casting) in the fit accuracy of three-unit, screw-retained fixed dental prostheses. MATERIALS AND METHODS: Sixteen three-unit implant-supported screw-retained frameworks were fabricated to fit an in vitro model. Eight frameworks were fabricated using the CAD/CAM system, four in zirconia and four in cobalt-chromium. Four zirconia frameworks were fabricated using the copy-milled system, and four were cast in cobalt-chromium using conventional casting with premachined abutments. The vertical and horizontal misfit at the implant-framework interface was measured using scanning electron microscopy at ×250. The results for vertical misfit were analyzed using Kruskal-Wallis and Mann-Whitney tests. The horizontal misfits were categorized as underextended, equally extended, or overextended. Statistical analysis established differences between groups according to the chi-square test (α = .05). RESULTS: The mean vertical misfit was 5.9 ± 3.6 µm for CAD/CAM-fabricated zirconia, 1.2 ± 2.2 µm for CAD/CAM-fabricated cobalt-chromium frameworks, 7.6 ± 9.2 µm for copy-milling-fabricated zirconia frameworks, and 11.8 (9.8) µm for conventionally fabricated frameworks. The Mann-Whitney test revealed significant differences between all but the zirconia-fabricated frameworks. A significant association was observed between the horizontal misfits and the fabrication method. The percentage of horizontal misfits that were underextended and overextended was higher in milled zirconia (83.3%), CAD/CAM cobaltchromium (66.7%), cast cobalt-chromium (58.3%), and CAD/CAM zirconia (33.3%) frameworks. CONCLUSION: CAD/CAM-fabricated frameworks exhibit better vertical misfit and low variability compared with copy-milled and conventionally fabricated frameworks. The percentage of interfaces equally extended was higher when CAD/CAM and zirconia were used.

Bone Remodeling Around Implants with External Hexagon and Morse-Taper Connections: A Randomized, Controlled, Split-Mouth, Clinical Trial.

OBJECTIVES: To evaluate clinical, radiographic, microbiologic, and biomechanical parameters related to bone remodeling around implants with external hexagon (EH) and Morse-taper (MT) connections. MATERIALS AND METHODS: Twelve totally edentulous patients received four custom-made implants in the interforaminal region of the mandible. Two of those implants had the same macroscopic design, but different prosthetic connections. All patients received an immediate implant-supported prosthesis. Clinical parameters (periimplant probing pocket depth (PPD), modified gingival index (mGI), and mucosal thickness (MTh)) were evaluated at 12 months follow-up. The distance between the top of the implant and the first bone-to-implant contact (IT-FBIC) was evaluated on standardized digital peri-apical radiographs acquired at 1, 3, 6, and 12 months follow-up. Samples of the subgingival microbiota were collected 1, 3, and 6 months after implant loading and used for the quantification of Tanerella forsythia, Porphyromonas gingivalis, Aggragatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum. Further, 36 computerized-tomography based finite element (FE) models were accomplished, simulating each patient under three loading conditions. RESULTS: The evaluated clinical parameters were equal for EH and MT implants. Mean IT-FBIC was significantly different between the tested connections (1.17 ± 0.44 mm for EH, and 0.17 ± 0.54 mm for MT, considering all evaluated time periods). No significant microbiological differences could be observed between tested connections. FE analysis showed a significantly higher peak of equivalent (EQV) strain (p = 0.005) for EH (mean 3,438.65 µÎµ) compared to MT (mean 840.98 µÎµ) connection. CONCLUSIONS: Radiographic periimplant bone loss depends on the implant connection type. MT connections showed less periimplant bone loss, compared to EH connections.

Effects of new implant-retained overdentures on masticatory function, satisfaction and quality of life.

The aim of this study is to evaluate the effects of replacing poorly fitting dentures on patient's masticatory function, satisfaction and oral health-related quality of life. Fourteen patients with conventional maxillary complete dentures and mandibular overdentures retained by two implants bar clip system had their dentures replaced. The laboratory tests for the analysis of masticatory performance were conducted using an "Optocal" food simulator test. Questionnaires were used to evaluate patient satisfaction with dentures and impact of oral health on quality of life. Tests were conducted and questionnaires were administered before and 1, 3 and 6 months after the patient had adapted to the new dentures. Masticatory performance data and satisfaction with dentures (Visual Analogic Scale) were statistically analyzed by ANOVA and Tukey b test, satisfaction with dentures (SATs P) and impact of oral health on quality of life were evaluated using the Wilcoxon and Friedman tests (a=.05). There was no statistically significant improvement in masticatory function after denture replacement, although better outcomes were observed. Satisfaction with dentures and total score obtained using the OHIPedent showed significant improvement. It can be suggested that the potential for grinding food, patient satisfaction and aspects of quality of life improved immediately after denture replacement.

Avaliar os efeitos da substituição de próteses mal adaptadas na função mastigatória, satisfação e qualidade de vida relacionada à saúde bucal do paciente. Quatorze pacientes com próteses totais convencionais maxilarese overdentures retidas por dois implantes mandibularessistem abarra clip etiveram suas prótes essubstituídas .Os testes laboratoriais para análise da performance mastigatória foram realizados utilizando um simulador de alimento "Optocal". Foram utili za dos questionários para avaliar a satisfação com a prótese eo impacto da saúde bucal na qualidade de vida. Os testes foram realizados e os questionários foram aplicados antes, 1, 3 e 6 mes esapós o paciente ter adaptado às novas próteses. Os dados da performance mastigatória e satisfação com a prótese (EscalaAnalógica Visual) foram analisados estatistica mente por análise de variância e teste de Tukey b, a satisfação com próteses (SATs P) e o impacto da saúde bucal na qualidade de vida foram avaliados pormeio dos testes de Wilcoxon e Friedman (a = 0,05). Não houvem elhora estatisticamente significativa na função mastigatória após a troca daspróteses, em boram elhores resultados foram observados após a substituição. Satisfação com a prótese e a somatória total obtida utilizando o OHIPEdent mostraram melhora signi ficativa. Podese sugerir que o potencial de trituração dos alimentos, a satisfação do paciente com as nova spróteses e aspectos da qualidade de vida melhorar amimediatamente após a substituição da prótese.

Effects of new implant-retained overdentures on masticatory function, satisfaction and quality of life

The aim of this study is to evaluate the effects of replacing poorly fitting dentures on patient’s masticatory function, satisfaction and oral healthrelated quality of life. Fourteen patients with conventional maxillary complete dentures and mandibular overdentures retained by two implants bar clip system had their dentures replaced. The laboratory tests for the analysis of masticatory performance were conducted using an “Optocal” food simulator test. Questionnaires were used to evaluate patient satisfaction with dentures and impact of oral health on quality of life. Tests were conducted and questionnaires were administered before and 1, 3 and 6 months after the patient had adapted to the new dentures. Masticatory performance data and satisfaction with dentures (Visual Analogic Scale) were statistically analyzed by ANOVA and Tukey b test, satisfaction with dentures (SATs P) and impact of oral health on quality of life were evaluated using the Wilcoxon and Friedman tests (a=.05). There was no statistically significant improvement in masticatory function after denture replacement, although better outcomes were observed. Satisfaction with dentures and total score obtained using the OHIPedent showed significant improvement. It can be suggested that the potential for grinding food, patient satisfaction and aspects of quality of life improved immediately after denture replacement.

Avaliar os efeitos da substituição de próteses mal adaptadas na função mastigatória, satisfação e qualidade de vida relacionada à saúde bucal do paciente. Quatorze pacientes com próteses totais convencionais maxilares e overdentures retidas por dois implantes mandibulares sistema barra clip e tiveram suas próteses substituídas .Os testes laboratoriais para análise da performance mastigatória foram realizados utilizando um simulador de alimento “Optocal”. Foram utili za dos questionários para avaliar a satisfação com a prótese eo impacto da saúde bucal na qualidade de vida. Os testes foram realizados e os questionários foram aplicados antes, 1, 3 e 6 meses após o paciente ter adaptado às novas próteses. Os dados da performance mastigatória e satisfação com a prótese (EscalaAnalógica Visual) foram analisados estatistica mente por análise de variância e teste de Tukey b, a satisfação com próteses (SATs P) e o impacto da saúde bucal na qualidade de vida foram avaliados pormeio dos testes de Wilcoxon e Friedman (a = 0,05). Não houve melhora estatisticamente significativa na função mastigatória após a troca das próteses, embora melhores resultados foram observados após a substituição. Satisfação com a prótese e a somatória total obtida utilizando o OHIPEdent mostraram melhora significativa. Pode se sugerir que o potencial de trituração dos alimentos, a satisfação do paciente com as novas próteses e aspectos da qualidade de vida melhoraram imediatamente após a substituição da prótese.

Placement of a distal implant to convert a mandibular removable Kennedy class I to an implant-supported partial removable Class III dental prosthesis: A systematic review.

STATEMENT OF PROBLEM: A number of authors have reported the placement of a distal implant associated with a partial removable dental prosthesis (PRDP) to make this rehabilitation more stable. This strategy may represent an option for resolving the problem of the intrusive movements of the PRDP and for reducing treatment costs. PURPOSE: The purpose of this systematic review was to evaluate the current evidence about the placement of a distal implant associated with a mandibular PRDP to improve patient satisfaction and the clinical performance of the abutment tooth and distal implant. MATERIAL AND METHODS: Two independent prosthetic specialist reviewers conducted this systematic review. The search was performed using selected clinical studies with PRDP associated with distal implants published in English up to May 2014 from the PubMed and Cochrane Library databases. A data extraction form was developed to collect general information: authors, title, year of publication, aim of study, level of evidence, number of participants, number of implants used, implant system, implant length and diameter, abutment type, masticatory performance, patient satisfaction, implant mean bone loss, abutment tooth mean bone loss, prosthetic complications, follow-up period, and implant survival rate. The quality of the selected studies and the risk of bias were also reported. RESULTS: The initial electronic search identified 231 studies, and the manual process identified 15 studies (total of 246 studies). After the title and abstract reading and the removal of duplicates, the full texts of 43 studies were obtained. The articles that did not meet the inclusion criteria were excluded (28 studies), and the data from 15 studies were extracted. Seven were retrospective studies, 1 a crossover pilot study, 2 case series, 2 paired clinical studies, and 3 case reports, demonstrating that a high number of the selected studies were of low methodological quality. Nevertheless, the high survival rates for PRDP associated with dental implants have been described. CONCLUSIONS: The use of a PRDP associated with dental implants to convert a Kennedy class I to class III dental prosthesis benefits patients by improving their satisfaction and masticatory abilities without decreasing implant survival rates. Considering the abutment tooth survival rate, clinical studies with comparable methodology are still lacking to define protocols regarding the use of distal implants associated with PRDP. Long-term, prospective clinical trials are still needed to understand which implant abutments increase abutment tooth survival rate.

Influence of CAD/CAM on the fit accuracy of implant-supported zirconia and cobalt-chromium fixed dental prostheses.

STATEMENT OF PROBLEM: Relatively little information is available on the accuracy of the abutment-implant interface in computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated zirconia and cobalt-chromium frameworks. PURPOSE: The purpose of this study was to compare the fit accuracy of CAD/CAM-fabricated zirconia and cobalt-chromium frameworks and conventionally fabricated cobalt-chromium frameworks. MATERIAL AND METHODS: Four groups of 3-unit, implant-supported, screw-retained frameworks were fabricated to fit an in vitro model with 3 implants. Eight frameworks were fabricated with the CAD/CAM system: 4 in zirconia and 4 in cobalt-chromium. Another 8 were cast in cobalt-chromium with conventional casting, including 4 with premachined abutments and 4 with castable abutments. The vertical misfit at the implant-framework interface was measured with scanning electron microscopy when only 1 screw was tightened and when all screws were tightened. Data were analyzed with the Kruskal-Wallis and Mann-Whitney tests (α=.05). RESULTS: The mean vertical misfit values when all screws were tightened was 5.9 ±3.6 µm for CAD/CAM-fabricated zirconia, 1.2 ±2.2 µm for CAD/CAM-fabricated cobalt-chromium frameworks, 11.8 ±9.8 µm for conventionally fabricated cobalt-chromium frameworks with premachined abutments, and 12.9 ±11.0 µm for the conventionally fabricated frameworks with castable abutments; the Mann-Whitney test found significant differences (P<.05) among all frameworks, except between the conventionally fabricated frameworks (P=.619). No significant differences were found among the groups for passive fit gap measurements (P>.05). CONCLUSIONS: When all of the screws were tightened, the CAD/CAM frameworks exhibited better fit accuracy compared with the conventionally fabricated frameworks. High levels of passive fit were achieved for the evaluated techniques.

Remodelação óssea de implantes com conexão hexágono externo e elementos de retenção no módulo da crista sob carregamento imediato – estudo clínico prospectivo longitudinal de um ano / Bone remodeling of implants with external hexagon connection and retention elements at the crestal module under immediate loading – a 1-year longitudinal prospective clinical trial

Objetivo: avaliar a remodelação óssea radiográfica ao redor de implantes hexágono externo (EH) que possuem roscas no módulo da crista. Material e métodos: doze pacientes desdentados totais receberam quatro implantes (Ø 3,8 mm x 13 mm) customizados na região interforaminal. Doze desses implantes foram hexágono externo com roscas no módulo da crista. Todos os pacientes receberam uma prótese implantossuportada imediata. A distância entre o topo do implante e o primeiro contato osso/implante (IT-FBIC) foi avaliada em radiografias periapicais digitais padronizadas adquiridas em um, três, seis e 12 meses de acompanhamento. A comparação entre vários períodos de observação foi realizada utilizando análise de variância (Anova) para medidas repetidas, seguida pelo teste post-hoc de Tukey. Resultados: a variação radiográfica da perda óssea peri-implantar foi significativamente diferente entre os períodos de acompanhamento (p < 0,001). A média de IT-FBIC foi de 1,17 ± 0,44 mm, depois de 12 meses de carregamento funcional. Conclusão: a remodelação óssea peri-implantar ocorrerá para implantes com hexágono externo, independentemente da presença de elementos de retenção no módulo da crista do implante

Objective: to evaluate the radiographic bone remodeling around implants using external hexagon (EH) with a threaded implant crestal module. Material and methods: twelve patients with totally edentulous mandibles received four custom-made (Ø 3.8 x 13 mm) implants in the interforaminal region. Twelve of the implants were external hexagon with a threaded implant crestal module. All patients received an immediate implant-supported prosthesis. The distance between the top of the implant and the first bone-to-implant contact (IT-FBIC) was evaluated on standardized digital periapical radiographs acquired at one, three, six, and 12 months of follow-up. Comparison among multiple observation periods was performed using repeated-measures analysis of variance (Anova), followed by a Tukey post-hoc test. Results: the radiographic periimplant bone loss was significantly different among the follow-up periods (p < 0.001). Mean IT-FBIC was 1.17 mm ± 0.44 mm, at 12 months follow-up period. Conclusions: radiographic periimplant bone remodeling will occur for implants using external hexagon, regardless of the presence of retention elements at the implant crestal module.

Micro-computed tomography evaluation of marginal fit of lithium disilicate crowns fabricated by using chairside CAD/CAM systems or the heat-pressing technique.

STATEMENT OF PROBLEM: No consensus exists concerning the acceptable ranges of marginal fit for lithium disilicate crowns fabricated with either heat-pressing techniques or computer-aided design and computer-aided manufacturing (CAD/CAM) systems. PURPOSE: The purpose of the study was to evaluate with micro-computed tomography the marginal fit of lithium disilicate crowns fabricated with different chairside CAD/CAM systems (Cerec or E4D) or the heat-pressing technique. MATERIAL AND METHODS: Lithium disilicate crowns were fabricated to fit an in vitro cast of a single human premolar. Three fabrication techniques were used: digital impressions with Cerec 3D Bluecam scanner with titanium dioxide powder, followed by milling from IPS e.max CAD for Cerec; digital impressions with E4D Laser scanner without powder, followed by milling from IPS e.max CAD for E4D; and fabrication from IPS e.max Press by using the lost-wax and heat-pressing techniques. Each crown was fixed to the cast and scanned with micro-computed tomography to obtain 52 images for measuring the vertical and horizontal fit. Data were statistically analyzed by 1-way ANOVA, followed by the Tukey honestly significant difference test (α=.05). RESULTS: The mean values of vertical misfit were 36.8 ±13.9 µm for the heat-pressing group and 39.2 ±8.7 µm for the Cerec group, which were significantly smaller values than for the E4D group at 66.9 ±31.9 µm (P=.046). The percentage of crowns with a vertical misfit <75 µm was 83.8% for Cerec and heat-pressing, whereas this value was 65% for E4D. Both types of horizontal misfit (underextended and overextended) were 49.2% for heat-pressing, 50.8% for Cerec, and 58.8% for E4D. CONCLUSIONS: Lithium disilicate crowns fabricated by using the Cerec 3D Bluecam scanner CAD/CAM system or the heat-pressing technique exhibited a significantly smaller vertical misfit than crowns fabricated by using an E4D Laser scanner CAD/CAM system.

Effects of abutment taper on the uniaxial retention force of cement retained implant restorations / Effects of abutment taper on the uniaxial retention force of cement retained implant restorations / Efeito da conicidade do pilar na resistência de união de coroas cimentadas sobre implantes

Aim: The purpose of this study was to evaluate the bond strength of metallic crowns cemented to straight and angled customizable abutments with zinc phosphate. Material and Method: Thirty-nine external hex nalogs and abutments were divided in group S: customizable straight abutment (n = 10), group A17 with 17° angled abutment (n = 10) and group A30 with 30° angled abutment (n = 10) all cemented with zinc phosphate. The metal copings were cemented onto their corresponding metal dies according manufacture guidelines. Data from the all groups were compared with a 1-way ANOVA (?=.05) and Tukey's test. SEM evaluation were performed (n = 3) aiming to investigate microscopic features of the abutment-cement-crown interfaces. Results: The mean force (SD) required to dislodge the crowns in the S, A17 and A30 groups was 357.26 (62.21) N; 251.50 (20.13) N and 276.70 (17.96) N respectively. The Tukey test (p <0.05) revealed a significant statistically differences between the groups (p =.002) and the 17° angled abutment and 30° angled abutment group were statistically similar to each other and different from the group of straight abutments. Zinc phosphate showed an inhomogeneous cement line in SEM analysis. Conclusions: Within the limitations of this study, it can be conclude that the available surface area and convergence of the abutments axial walls of the straight abutments positively influenced bond strength in metallic crowns cemented with zinc phosphate.

Avaliação da eficiência mastigatória por dois métodos: colorimetria e tamises / Mastigatory function avaluation by two methods: colorimetry and sifters

Objetivo: Correlacionar dois métodos para verificação da performance mastigatória. Método: Foram selecionados 13 pacientes que portavam Prótese total superior e prótese parcial fixa classe I de Kennedy inferior para realizar dois testes que medem a performance mastigatória. O primeiro teste, chamado de método das tamises, utiliza-se do Optocal como alimento-teste, dividido em 3 porções com 17 g que o paciente deve mastigar realizando 20 ou 40 ciclos mastigatórios. Após isso, é feita a análise do DGM. Em seguida, o paciente realizava a mastigação de uma cápsula, contendo grânulos de fuccina, seguindo os mesmos ciclos mastigatórios descritos no outro método. Após isso, as cápsulas foram enviadas a laboratório específico para análise da coloração. Resultado: Não houve correlação entre os métodos testados, após análise estatística utilizando o método de correlação de Pearson, com ?=0.05. Conclusão: O método da colorimetria, embora mais simples e de fácil execução do que o método das tamises, não se mostrou correlato a este. Deve-se, portanto, realizar ajustes na cápsula, a fim de torná-la mais macia, ou no método de análise do corante.

Purpose: Correlating two methods of verification of masticatory performance. Method: Thirteen patients were selected with was reabilitated with maxillar total denture and mandibular removible partial Kennedy Class I denture to perform two tests witch measure masticatory performance. The first test, called the method of sieves, uses the Optocal as test-food, divided into three portions with 17 g that the patient should chew doing 20 or 40 masticatory cycles. After that, we perform the DGM? analysis. Then the patient should chew a capsule containing fuchsin beads, following the same chewing cycles described in the other method. Thereafter, the capsules were sent to a specific laboratory for analysis. Results: There was no correlation between the tested methods, after statistical analysis using the Pearson correlation method, with ? = 0.05. Conclusions: Even colorimetric method, was a simple and easy to perform method, it was not correlated to the sifters method. Adjustments are necessary, in the capsule in order to make it softer or in the analisys? method.

Avaliação da microinfltração bacteriológica em implantes hexágono externo com diferentes superfícies de parafuso / Bacterial microleakage in hexagonal implants with different screw surface

OBJETIVO: Avaliar a microinfltração bacteriana na interface entre implantes hexágono externo (HE) e pilares com diferentes tipos de parafusos. MATERIAIS E MÉTODOS: Foram selecionados 20 implantes HE e respectivo pilar, divididos em 2 grupos em função do tipo de parafuso do pilar (n=10). PT: Parafuso de Titânio e PDLC: Parafuso de Diamond Like Carbon (DLC). Uma suspensão bacteriana de Escherichia coli ATCC 35218 foi preparada a uma densidade padrão de 0,5 McFarland para inoculação de 0,5 µL de suspensão no interior dos implantes. Todos os pilares foram apertados com torque de 32 N seguindo recomendações do fabricante. A microinfltração foi avaliada pela análise da claridade da suspensão a cada 24 horas durante 14 dias. Ao final deste período a viabilidade da bactéria foi verifcada. RESULTADOS: Durante o período de acompanhamento nenhuma das amostras apresentou microinfltração bacteriana. Após 14 dias a viabilidade bacteriana foi comprovada. CON-CLUSÃO: Considerando as limitações deste estudo, pode-se concluir que não foi observada a microinfltração bacteriana na interface pilar/ implante nos grupos avaliados e não foi possível estabelecer a infuência de parafusos com diferentes superfícies nesta microinfltração.

The aim of this study was to evaluate the bacterial microleakage at the interface between external hexagon implant (HE) and abutments with diferent types of screws. 20 implants and respective abutments had been selected, divided into 2 groups, depending on the abutment screw (n=10): Titanium screw (PT) and "Diamond Like Carbon" DLC Screw (PDLC). Escherichia coli bacterial suspension ATCC 35218 was prepared at a density 0,5 McFarland standard for suspension inoculation of 0.5 mL in the inner of the implants. All abutments were tightened with 32 N following the manufacturer's recommendations. Microleaka-ge was assessed the clarity of the suspension every 24 hours for 14 days. To the end of this period the viability of the bacterium was verifed. At the time of accompaniment none of the samples presented bacterial microleakage. Microleakage was assessed the clarity of the suspension every 24 hours for 14 days. There-after the viability of bacteria was found. During the monitoring period none of the samples showed bacterial microleakage. After 14 days the bacterial viability was confrmed. Considering the limitations of this study, it can conclude that the Bacterial leakage was not observed in the abutment/implant interface in the evaluated groups and was unable to establish the infuence of screws with diferent surfaces in this microleakage.

Avaliação comparativa da microinfiltração bacteriológica na interface pilar/implante em implantes hexágono externo com 10 e 20Ncm de torque / Comparative evaluation of the bacteriological microleakage in the implant/abutment interface in external hexagon implants with 10 and 20Ncm torque

O objetivo deste estudo foi avaliar a infltração na interface entre implantes hexágono externo (HE) e pilar cônico inseridos com diferentes torques. Uma suspensão bacteriana de Escherichia coli ATCC 35218 foi preparada em caldo nutritivo de Brain Heart Infusion a uma densidade padrão de 0,5 McFarland para inoculação dos implantes. Na primeira fase do experimento foram utilizados nove implantes (HE) e respectivo parafuso e pilar Cônico, divididos aleatoriamente em 3 grupos com diferentes volumes de inoculação da suspensão bacteriana (n=3). V0,5: 0,5 µL; V1,0: 1,0 µL e V1,5: 1,5 µL. Todos os implantes foram apertados com torque recomendado pelo fabricante. Na segunda fase do experimento foram utilizados 18 implantes e componentes semelhantes à fase 1. Estes foram inoculados com 0,5 µL de suspensão bacteriana e divididos em grupos apertados com diferentes torques (n=9). T10: 10 Ncm e T20: 20 Ncm. Os conjuntos foram avaliados pela análise da claridade da solução a cada 24 horas por 14 dias. Ao fnal deste período a viabilidade da bactéria foi verifcada. O teste de Kruskal-Wallis foi realizado para comparação entre os grupos (p<0,05). Na primeira fase V1,0 e V1,5 apresentaram indicativo de contaminação bacteriana em todas as amostras após 24 hs. Na segunda fase duas amostras do T10 e uma do T20 apresentaram resultado positivo para contaminação bacteriana. Os resultados mostraram que a intensidade do torque não infuenciou estaticamente na microinfiltração bacteriana em implantes HE. Após 14 dias a viabilidade bacteriana foi confirmada.

The aim of this study was to evaluate the infiltration at the interface between implant external hexagon (HE) and conical pillar inserted with different torques. A bacterial suspension of Escherichia coli ATCC 35 218 was prepared in nutrient broth of Brain Heart Infusion at a density of 0.5 McFarland standard for inoculation in the implants. In the first phase of the experiment, nine implants (HE) and its tapered abutment screw were randomly divided into three groups with diferent volumes of inoculation of bacterial suspension (n = 3). V0, 5: 0.5 mL, V1, 0: 1.0 mL and V1, 5: 1.5 mL. All implants were tightened with a recommended torque by the manufacturer. In the second phase of the experiment 18 implants and components were used similar to Phase 1. These were inoculated with 0.5 mL of bacterial suspension and divided into groups with diferent torques tight (n = 9). T10: 10 Ncm and T20: 20 Ncm. The sets were evaluated by the clarity of the solution every 24 hours for 14 days. Thereafter the viability of bacteria was found. The Kruskal-Wallis test was performed for comparison between groups (p < 0.05). In the first stage V1, and V 1, 5 presented indications of bacterial contamination in all samples after 24 hours. In the second phase of the two samples of T10 and T20 were positive for bacterial contamination. The results showed that the intensity of torque did not influence the microleakage statically bacterial HE implants. After 14 days the bacterial viability was confirmed.