Bacterial infiltration and detorque at the implant abutment morse taper interface after masticatory simulation.

This study evaluated the bacterial infiltration and the detorque of indexed and non-indexed abutments of Morse taper implants (MTI) after mechanical cycling (MC). 40 MTI were distributed into four groups: IIA (indexed implant abutments); NIIA (non-indexed implant abutments); IIAMC (indexed implant abutments submitted to MC); NIIAMC (non-indexed implant abutments submitted to MC), which were carried out under one million 5 Hz frequency and 3 Bar pressure. After mechanical cycling, all groups were immersed in a bacterial solution in Brain Heart Infusion Agar. After detorque, the bacteria infiltration was evaluated by counting the colony-forming units. For the bacterial infiltration, analysis was applied to the Kruskal-Wallis test (p = 0.0176) followed by Dunn's test. For the detorque analysis, the two-way repeated-measures ANOVA was applied, followed by the Tukey's test (p < 0.0001). Bacteria infiltration was highly observed in NIIA (p = 0.0027) and were absent in IIAMC and NIIAMC. The detorque values for IIA (19.96Ncm ± 0.19Ncm), NIIA (19.90Ncm ± 0.83Ncm), and NIIAMC (19.51Ncm ± 0,69Ncm) were similar and remained close to the initial value, while IIAMC (55.2Ncm ± 2.36Ncm) showed an extremely significant torque value increase (p < 0.0001). The mechanical cycling resulted in mechanical sealing of the implant-abutment interface, preventing bacterial infiltration in the indexed and non-indexed specimens, and increasing the detorque strength in the group of indexed abutments.

Evaluation of the Accuracy of Conventional and Digital Impression Techniques for Implant Restorations.

PURPOSE: The increased use of CAD systems can generate doubt about the accuracy of digital impressions for angulated implants. The aim of this study was to evaluate the accuracy of different impression techniques, two conventional and one digital, for implants with and without angulation. MATERIALS AND METHODS: We used a polyurethane cast that simulates the human maxilla according to ASTM F1839, and 6 tapered implants were installed with external hexagonal connections to simulate tooth positions 17, 15, 12, 23, 25, and 27. Implants 17 and 23 were placed with 15° of mesial angulation and distal angulation, respectively. Mini cone abutments were installed on these implants with a metal strap 1 mm in height. Conventional and digital impression procedures were performed on the maxillary master cast, and the implants were separated into 6 groups based on the technique used and measurement type: G1 - control, G2 - digital impression, G3 - conventional impression with an open tray, G4 - conventional impression with a closed tray, G5 - conventional impression with an open tray and a digital impression, and G6 - conventional impression with a closed tray and a digital impression. A statistical analysis was performed using two-way repeated measures ANOVA to compare the groups, and a Kruskal-Wallis test was conducted to analyze the accuracy of the techniques. RESULTS: No significant difference in the accuracy of the techniques was observed between the groups. Therefore, no differences were found among the conventional impression and the combination of conventional and digital impressions, and the angulation of the implants did not affect the accuracy of the techniques. CONCLUSIONS: All of the techniques exhibited trueness and had acceptable precision. The variation of the angle of the implants did not affect the accuracy of the techniques.

Strain Gauge Evaluation of Transfer Impression Techniques of Multiple Implant-Supported Prosthesis.

PURPOSE: This in vitro study assessed the accuracy of multiple implant-level impression techniques (open tray and closed tray) for the fabrication of 3-unit implant prostheses with strain gauge (SG) analysis. MATERIALS AND METHODS: A polyurethane master model was designed to simulate a clinical situation. Two rigid custom trays were fabricated for the model. The impression material used was polysulfide. Transfer implant impressions were made using 2 techniques; ten tapered copings not splinted (custom closed tray) and ten square copings splinted with acrylic-resin (custom open tray). The improved stone models were allowed to set for 1 hour before being separated from the impression. The superstructures were sprued, invested, and cast with a cobalt-chromium alloy. Four SGs were bonded on the surface of each polyurethane block. RESULTS: A statistically significant difference was found between the 2 impression techniques tested (P = 0.000). This study found a significant average difference of 144.68 ± 5.53 µÎµ for open custom tray and 253.3 ± 16.7 µÎµ for closed custom tray. CONCLUSION: The custom open tray technique was the most accurate impression for multiple implants compared with closed custom tray.

Removable Partial Denture with dual path of insertion: clinical case report / PPR com dupla trajetória de inserção: relato de caso clínico

Removable Partial Dentures (RPD) with dual path of insertion are designed to overcome conventional RPD esthetic limitations, through the use of proximal undercuts for rigid direct retainers. Therefore, dual path RPD is considered a variation of conventional RPD. This paper reports a clinical case where proper function as well as excellent esthetics were obtained with this type of RPD. (AU)

Próteses parciais removíveis (PPR) com dupla trajetória de inserção são próteses projetadas para superar limitações estéticas das próteses convencionais, utilizando-se retentores diretos rígidos nas áreas retentivas proximais dos dentes suportes. Desta forma, a PPR com dupla trajetória da inserção é considerada uma variação da PPR tradicional. O objetivo deste artigo é relatar um caso clínico onde se obteve uma resolução funcional e altamente estética através deste tipo de PPR..(AU)

Zirconia Rehabilitation Focused on the Emergence Profile: A Case Report.

The first choice for anterior rehabilitation has been metal-free materials due to their successful aesthetic results. However, the definitive clinical work accuracy may be affected by the lack of clinicians' expertise and familiarization with the latest techniques, as well as recurrent laboratory procedures. This manuscript presents a clinical experience with zirconia ceramic for anterior crowns and zirconia CAD/CAM abutments, including both clinical and laboratory steps after the implant installation. The 'emergence profile' and the 'double scanning' techniques obtained by the waxing technique appear to be a very promising procedure for aesthetic improvement of the single-implant zirconia restoration in anterior teeth.

Effect of Jig Design and Assessment of Stress Distribution in Testing Metal-Ceramic Adhesion.

PURPOSE: In testing adhesion using shear bond test, a combination of shear and tensile forces occur at the interface, resulting in complex stresses. The jig designs used for this kind of test show variations in published studies, complicating direct comparison between studies. This study evaluated the effect of different jig designs on metal-ceramic bond strength and assessed the stress distribution at the interface using finite element analysis (FEA). MATERIALS AND METHODS: Metal-ceramic (Metal: Ni-Cr, Wiron 99, Bego; Ceramic: Vita Omega 900, Vita) specimens (N = 36) (diameter: 4 mm, veneer thickness: 4 mm; base diameter: 5 mm, thickness: 1 mm) were fabricated and randomly divided into three groups (n = 12 per group) to be tested using one of the following jig designs: (a) chisel (CH) (ISO 11405), (b) steel strip (SS), (c) piston (PI). Metal-ceramic interfaces were loaded under shear until debonding in a universal testing machine (0.5 mm/min). Failure types were evaluated using scanning electron microscopy (SEM). FEA was used to study the stress distribution using different jigs. Metal-ceramic bond strength data (MPa) were analyzed using ANOVA and Tukey's tests (α = 0.05). RESULTS: The jig type significantly affected the bond results (p = 0.0001). PI type of jig presented the highest results (MPa) (p < 0.05) (58.2 ± 14.8), followed by CH (38.7 ± 7.6) and SS jig type (23.3 ± 4.2) (p < 0.05). Failure types were exclusively a combination of cohesive failure in the opaque ceramic and adhesive interface failure. FEA analysis indicated that the SS jig presented slightly more stress formation than with the CH jig. The PI jig presented small stress concentration with more homogeneous force distribution compared to the CH jig where the stress concentrated in the area where the force was applied. CONCLUSION: Metal-ceramic bond strength was affected by the jig design. Accordingly, the results of in vitro studies on metal-ceramic adhesion should be evaluated with caution. CLINICAL SIGNIFICANCE: When adhesion of ceramic materials to metals is evaluated in in vitro studies, it should be noted that the loading jig type affects the results. Clinical observations should report on the location and type of ceramic fractures in metal-ceramic reconstructions so that the most relevant test method can be identified.

Axial loads on implant-supported partial fixed prostheses for external and internal hex connections and machined and plastic copings: strain gauge analysis.

The aim of this in vitro study was to use strain gauge (SG) analysis to compare the effects of the implant-abutment joint, the coping, and the location of load on strain distribution in the bone around implants supporting 3-unit fixed partial prostheses. Three external hexagon (EH) implants and 3 internal hexagon (IH) implants were inserted into 2 polyurethane blocks. Microunit abutments were screwed onto their respective implant groups. Machined cobalt-chromium copings and plastic copings were screwed onto the abutments, which received standard wax patterns. The wax patterns were cast in a cobalt-chromium alloy (n = 5): group 1 = EH/machined. group 2 = EH/plastic, group 3 = IH/machined, and group 4 = IH/plastic. Four SGs were bonded onto the surface of the block tangentially to the implants. Each metallic structure was screwed onto the abutments and an axial load of 30 kg was applied at 5 predetermined points. The magnitude of microstrain on each SG was recorded in units of microstrain (µÎµ). The data were analyzed using 3-factor repeated measures analysis of variance and a Tukey test (α = 0.05). The results showed statistically significant differences for the type of implant-abutment joint, loading point, and interaction at the implant-abutment joint/loading point. The IH connection showed higher microstrain values than the EH connection. It was concluded that the type of coping did not interfere in the magnitude of microstrain, but the implant/abutment joint and axial loading location influenced this magnitude.

Sistema CAD/CAM: uma alternativa para infraestruturas metálicas fundidas para próteses totais fixas implantossuportadas / The CAD/CAM system: an alternative to cast metal frameworks for complete fixed dental implant-supported prosthesis

Este trabalho relata um caso clínico do uso do sistema CAD/CAM para confecção da infraestrutura metálica. Um paciente de 57 anos de idade apresentava-se com uma prótese total metalocerâmica superior de longa data e próteses mandibulares bilaterais sobre dois implantes cada, afetados pela peri-implantite. O planejamento incluiu a remoção dos implantes afetados e a colocação de quarto novos implantes entre os forâmenes mentonianos, mas sem carregamento imediato em função da atividade parafuncional do paciente. A infraestrutura metálica foi fresada a partir de uma bolacha de CoCr em dez minutos. Cada cantiléver apresentou extensão de 20 mm. A adaptação passiva da prótese mandibular definitiva confirmou as possibilidades e benefícios da tecnologia CAD/CAM para próteses totais fixas implantossuportadas.

This paper reports a clinical case where a CAD/CAM system was used to fabricate a metallic framework. A 57 years-old patient presented with an old tooth-supported fused-to-metal prosthesis in the maxilla and bilateral mandibular implant-supported prostheses (two implants each) affected by peri-implantitis. The treatment planning included removal of infected implants and placement of four new dental implants between mental foramina, but with no immediate loading due to the patient´s parafunctional activities. The metallic infra-structure was milled from a CoCr disk in ten minutes. Each cantilever had a 20 mm-length. The passive fit of the definitive mandibular prosthesis was deemed excellent and confirmed the possibilities and benefi ts of the CAD/CAM technology for complete fixed implant-supported prostheses.

A microstrain comparison of passively fitting screw-retained and cemented titanium frameworks.

STATEMENT OF PROBLEM: An imprecise fit between frameworks and supporting dental implants in loaded protocols increases the strain transferred to the periimplant bone, which may impair healing or generate microgaps. PURPOSE: The purpose of this study was to investigate the microstrain between premachined 1-piece screw-retained frameworks (group STF) and screw-retained frameworks fabricated by cementing titanium cylinders to the prefabricated framework (group CTF). This procedure was developed to correct the misfit between frameworks and loaded implants. MATERIAL AND METHODS: Four internal hexagon cylindrical implants were placed 10 mm apart in a polyurethane block by using the surgical guides of the corresponding implant system. Previously fabricated titanium frameworks (n=10) were divided into 2 groups. In group STF, prefabricated machined frameworks were used (n=5), and, in group CTF, the frameworks were fabricated by using a passive fit procedure, which was developed to correct the misfit between the cast titanium frameworks and supporting dental implants (n=5). Both groups were screw-retained under torque control (10 Ncm). Six strain gauges were placed on the upper surface of the polyurethane block, and 3 strain measurements were recorded for each framework. Data were analyzed with the Student t test (α=.05). RESULTS: The mean microstrain values between the framework and the implants were significantly higher for group STF (2517 mε) than for group CTF (844 mε) (P<.05). CONCLUSIONS: Complete-arch implant frameworks designed for load application and fabricated by using the passive fit procedure decreased the strain between the frameworks and implants more than 1 piece prefabricated machined frameworks.

Evaluation of crosshead speed influence on shear bond strength test / Avaliação da influência da velocidade no ensaio de resistência ao cisalhamento

The objective of this study was to evaluate the influence of different speeds using the piston device in the shear bond strength. 48 cylinders of composed resin had been confectioned (Solidex),and were divided randomly in four groups (n=12). The specimens were adapted to the device for the shear bond strenth test and were taken to an universal testing machine with a load cell of 1000 Kg. The test were carried through with four different speeds: group A: 0.5; group B: 1.0; group C: 1.5 and group D: 2.0 mm/min. The mean and standard deviations, in Kgf, were: A - 66,31 (10,24); B - 64,53 (20,40); C - 75,23 (11,84) and D - 66,62 (13,81). The data were submitted to ANOVA (p = 0.13). The results indicated that it did not have statistical significant difference between the groups A, B, C and D concluding that the speed in this type of test, with this device, can be varied without modify results

O objetivo do presente estudo foi avaliar a influência de diferentes velocidades usando o dispositivo pistão para o ensaio de cisalhamento. Foram confeccionados 48 cilindros em resina composta microhíbrida (Solidex), divididos aleatoriamente em quatro grupos (n = 12). As amostras foram adaptadas ao dispositivo para o ensaio de cisalhamento e levadas a uma máquina de ensaios universal com uma célula de carga de 1000 Kg. Os ensaios foram realizados com quatro velocidades diferentes: grupo A: 0,5 mm/min; grupo B 1,0 mm/ min; grupo C: 1,5 mm/min e grupo D 2,0 mm/min. Os valores médios e desvios padrão obtidos, em Kgf, foram: grupo A: 66,31 ± 10,24; grupo B: 64,53 ± 20,40; grupo C: 75,23 ± 11,84 e grupo D: 66,62 ± 13,81. Os dados foram submetidos ao teste ANOVA (p = 0,13). Os resultados indicaram que não houve diferença estatisticamente significante entre os grupos A, B, C e D concluindo que se pode variar a velocidade neste tipo de ensaio, utilizando o dispositivo pistão, sem que os resultados fossem alterados

Avaliação por extensometria da deformação superficial do osso, gerada por próteses sobre implantes com diferentes pilares protéticos em função do cantilever: estudo in vitro / Strain gauge analysis of coronal bone deformation according different prosthetic implant abutment and cantilever length types: an in vitro study

O objetivo deste estudo foi avaliar a transmissão da carga mastigatória ao osso de suporte em próteses implantossuportadas em função do cantiléver, variando o tipo de pilar (Micro-Unite Ucla). A partir de dois modelos de poliuretano (norma ASTM F –1839), foram inseridos três implantes em cada, a uma distância de 8 mm, que conformaram os grupos: 1) implantes de hexágono externo e pilares Micro-Unit; 2) implantes de hexágono externo e pilares Ucla. Foram confeccionadas estruturas protéticas em resina acrílica ativada quimicamente sob cilindros com base de Co-Cr, que foram fundidas pela técnica convencional à brasagem. Foram fixados extensômetros no poliuretano entre os implantes e um na distal do implante mais próximo ao cantiléver. Em uma máquina de ensaio universal (2000RK – Kratos, São Paulo, Brasil), foi realizada a aplicação da carga de 150 N. A carga foi aplicada entre os implantes e no cantiléver nos intervalos de 5, 10, 15, 20 e 25 mm. Os dados obtidos foram analisados estatisticamente para cada extensômetro e levando em consideração a extensão do cantiléver. Quanto maior a extensão do cantiléver, maior a deformação superficial do osso ao redor do implante mais distal. A utilização do componente tipo Micro-Unit apresentou valores de deformação inferiores em relação ao Ucla.

Objectives: to evaluate transmission of masticatory loads according to different prosthetic implant abutment and cantilever lengths. Material and methods: two polyurethane models (ASTM F-1839) received 3 external hex dental implants 8 mm each apart divided into two groups: 1) Micro-Unit and, 2) Ucla. Metallic frameworks were prepared using acrylic resin and cast over CoCr prosthetic cylinders. Strain gauges were attached at the polyurethane-abutment interface and at the distal part of the implant near the cantilever. After, a 150 N load (2000 RK, Kratos, São Paulo, Brazil) was applied at 15, 20, and 25 mm from the most distal implant. Statistical analysis considered abutment type and cantilever lengths. Results: longer cantilevers generate more deformation in the distal implant. Deformation values at Micro-Unit were lower than at Ucla abutment type.

Microstrain around dental implants supporting fixed partial prostheses under axial and non-axial loading conditions, in vitro strain gauge analysis.

The current study used strain gauge analysis to perform an in vitro evaluation of the effect of axial and non-axial loading on implant-supported fixed partial prostheses, varying the implant placement configurations and the loading points. Three internal hexagon implants were embedded in the center of each polyurethane block with in-line and offset placements. Microunit abutments were connected to the implants using a torque of 20 N · cm, and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n = 10). Four strain gauges (SGs) were bonded onto the surfaces of the blocks, tangentially to the implants: SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments using a 10-N·cm torque, and axial and non-axial loads of 30 kg were applied at 5 predetermined points. The data obtained from the strain gauge analyses were analyzed statistically through the repeated measures analysis of variance and the Tukey test, with a conventional level of significance of P < 0.05. The results showed a statistically significant difference for the loading point (P = 0.0001), with point E (nonaxial) generating the highest microstrain (327.67 µ[Latin Small Letter Open E]) and point A (axial) generating the smallest microstrain (208.93 µ[Latin Small Letter Open E]). No statistically significant difference was found for implant placement configuration (P = 0.856). It was concluded that the offset implant placement did not reduce the magnitude of microstrain around the implants under axial and non-axial loading conditions, although loading location did influence this magnitude.

Precisão da instalação de implantes com guias cirúrgicos obtidos por estereolitografia / On the accuracy of stereolithographic-guided dental implant placement: a clinical study

O presente estudo in vivo propôs avaliar a precisão de instalação de 23 implantes sem retalhos empregando guias cirúrgicos obtidos por estereolitografia em quatro pacientes com maxilas totalmente desdentadas. Após duplo escaneamento com tomografia computadorizada tipo cone-beam, o planejamento pré-cirúrgico foi realizado com o programa Procera. Depois da cirurgia, realizou-se a comparação entre as posições dos implantes planejados e executados através de tomografia computadorizada pós-operatória. Para comparação da posição e dos longos eixos das imagens dos implantes foram eleitos três pontos em cada implante planejado e executado: no centro do limite coronário (D1), no centro da porção central (D2), no centro do limite apical (D3). Assim, as distâncias e o ângulo (A1) formado entre os longos eixos dos implantes planejados e executados foram numericamente calculados. De acordo com a análise tomográfica, os implantes executados em relação aos implantes planejados apresentaram desvios médios de 0,72 mm para a posição D1; 0,98 mm para a posição D2; 1,45 mm para a posição D3; 1,92 graus para o ângulo A1. Concluiu-se que houve desempenho adequado para a utilização de protocolos de cirurgia guiada baseados no método empregado em associação com guias cirúrgicos produzidos pelo processo de estereolitografia. A transferência do planejamento protético-cirúrgico para o campo operatório foi considerada satisfatória, visto que viabilizou a instalação de implantes dentários nas situações propostas...

The aim of this in vivo study was to evaluate the placement accuracy of 23 dental implants with fl apless surgery using stereolithographic guides in four completely edentulous maxillary patients. After double scanning with cone beam computerized tomography (CBCT), the presurgical planning was performed using appropriate software (Procera). After surgery, executed and planned implant positions were compared using CBCT superimposing. Measurements were made at the center of three pre-selected points: coronal (D1), central (D2), and apical (D3) portions. Thus, the distances among points and the angle (A1) formed between the long axes of the planned/executed implants were calculated. Mean deviations were as the following: 0.72 mm at D1, 0.98 mm at D2, and 1.45 mm at D3 positions. The mean angular deviaton (A1) was 1.92 degrees. It was concluded that there was adequate performance with surgical guides produced by stereolithographic process. The transfer of prosthetic-surgical planning for the surgical area was considered satisfactory, since it allowed for implant placement in proposed situations...

Avaliação por extensometria de implantes de sextavado externo posicionados na configuração linear e compensada / Evaluation of external hex implants placed in linear and offset configuration using strain gauge analysis

O objetivo neste trabalho foi avaliar, por meio da extensometria, a distribuição de tensões ao redor de implantes em função dos diferentes locais para carregamento e configuração (linear e compensada). Para tanto, em um bloco de poliuretano, foram posicionados paralelos entre si e com uma configuração linear, implantes autorrosqueáveis de hexágono externo, com dimensões de 3,75 mm x 13 mm, a uma distância de 7 mm, de centro a centro. Em outro bloco, a fixação do meio foi deslocada em 2 mm para gerar uma configuração compensada (offset). Pilares protéticos Micro-unit, com 3 mm de cinta, foram instalados sobre as fixações. Com duas matrizes em aço inoxidável foram confeccionados dez enceramentos para cada bloco (n = 10). A seguir, esses padrões foram fundidos com uma liga de Co-Cr. Quatro extensômetros (strain gauges) foram colados na superfície superior de cada bloco, tangenciando a plataforma de cada fixação. Um carregamento de 30 kg durante dez segundos foi feito em cinco posições (A, B, C, D, E), sendo repetido três vezes para aquisição dos dados (em µɛ) pelo aparelho condicionador de sinais. Os dados obtidos foram submetidos a análise de variância (RM Anova) e teste de Tukey (p < 0,05). Como conclusão da análise dos resultados obtidos, pudemos observar que não houve diferença entre as configurações linear e compensada; havendo diferença estatisticamente significante para os locais de carregamento.

The aim of this study was to evaluate through strain gauge methods the load distribution around dental implants regarding different sites and configurations (linear and offset). Three cylindrical implants with external hexagon (3.75 mm x 13mm) connection were fixed parallel in a polyurethane model with 7 mm between their centers in a linear configuration. In another block, the middle implant was positioned 2 mm offset. After, micro-unit abutments (3 mm of metallic collar height) were tightened. Ten wax patterns were created for each block (n = 10) and cast in Cobalt-Chromium alloy. Four strain gauges were positioned on the upper surface of each polyurethane model around the implants. A 30 kg axial load was applied for 10 seconds in five positions (A, B, C, D, and E), with three repeated measurements for data aquisition (in µɛ) by the multichannel bridge machine. Data were submitted to Anova and Tukey´s test (p < 0.05). It was concluded that: 1) no difference was seen between the linear and offset configurations and 2) there was statistical significance for different loading sites

Resistência de união entre uma resina composta e uma liga metálica com diferentes tipos de tratamento superficial / Bond strength between composite resin and metal alloy with different surface treatments

Este estudo comparou a resistência de união da interface metal/resina compostacom diferentes tratamentos de superfície metálica. Material e Método: Trinta e trêspadrões de acrílico foram fundidos em CoCrMo com 25 X 3 X 0,5mm (ISO 9693).As amostras foram divididas em três grupos de acordo com os tratamentos de superfície:Grupo A – microesferas retentivas (150μm) + jateamento com partículasde 110μm de óxido de alumínio + primer para metal + três camadas de opaco pararesina composta; Grupo B (controle) – jateamento com partículas de 110μm de óxidode alumínio + primer para metal + três camadas de opaco para resina compostae o Grupo C – jateamento com partículas de 110μm de óxido de alumínio + duascamadas de opaco para porcelana + condicionamento ácido (10% ácido hidrofluorídrico)+ silano + agente de união, e após, usando uma matriz, uma camada deresina composta (8 x 3 x 1mm) foi aplicada. O ensaio de flexão de três pontos foiusado a uma velocidade constante de 0,5mm/min. Os dados foram submetidos àanálise estatística one way ANOVA e o teste Tukey (a = 5%). Resultados: A análisedescritiva dos dados estatísticos (kgf) para os Grupos A, B e C foram (3.167±0.483),(0.858±0.157) e (1.602±0.262) respectivamente. Os resultados mostraram que osvalores de resistência à flexão para todos os grupos diferiram estatisticamente(p<0.001) entre eles. Conclusão: Os resultados mostraram que os maiores valores deresistência de união foram obtidos com o tratamento de superfície usado no Grupo A.

The present study compared the bond strength of the composite resin-metal interfacewith different treatments on the metal. Material and Method: Thirty three acrylicpatterns were casted in CoCrMo with 25 X 3 X 0,5mm (ISO 9693). All metallicspecimens were divided in three groups according to the surfaces treatments: GroupA – retentive microballs (150μm) + sandblasting with aluminum oxide particles110μm (Al2O3) + metal primer + one layer of opaque resin; Group B (control)- sandblasting with aluminum oxide particles 110μm (Al2O3) + metal primer +three layers of opaque resin and Group C – sandblasting with aluminum oxide particles110μm (Al2O3) + two layers of opaque porcelain + acid conditioning (10%hydrofluoric acid gel for 4min) + silane + bonding agent. After, using a matrix,one layer of composite resin (8 x 3 x 1mm) was applied. The three-point flexuraltest was used at a cross-head speed of 0,5mm/min. These data were submitted toone way ANOVA and Tukey´s test (a = 5%). Results: Descriptive statistics data(kgf) for groups A, B and C were (3.167±0.483), (0.858±0.157) and (1.602±0.262)respectively. The results showed that mean flexural strength values for all groupsdiffer statistically (p <0.001) among them. The values of group A were significantlyhigher than the group B and C. Conclusion: The results showed highestvalues of bond strength were obtained with surface treatment used in A group.

Screw spreading: technical considerations and case report.

The spreading system is an alternative technique to the Summers osteotome. The crest expansion technique is a less invasive procedure in which the facial wall expands after the medullary bone is compressed against the cortical wall. It improves the density of the maxillary bone, which allows for greater initial stability of implants. A specific screw instrument, the "spreader," achieved a controlled and standardized dilation of the bone horizontally. The use of spreaders to enhance the dental implant site is a highly predictable procedure.

Avaliação de dois métodos de registro da relação central em desdentados totais / Evaluation of two methods for registering the centric relation in total edentulous

Objetivo: Comparar, no plano horizontal, as posições mandibulares determinadas por dois métodos de registro para determinação da posição de relação central (RC): inclinação da cabeça para trás (IC) os métodos guiado não forçado (GNF), em pacientes edêntulos. A hipótese nula é de que não haverá diferença entre os dois métodos. Material e Método: 20 pacientes desdentados totais foram selecionados para este estudo (n=20). Todos pacientes foram manipulados para posição de RC utilizando os métodos IC e GNF. A mensuração da posição de RC determinada por cada método foi registrada em um dispositivo extra-oral, cujas componentes foram fixados nos planos de orientação maxilar e mandibular. Para cada paciente, as duas posições de RC foram registradas no mesmo dispositivo extra-oral. Para mensurar as variações ânteroposteriores e laterais entre os pontos registrados por cada técnica, foi utilizado um projetor de perfil (Modelo 6C, Nikon/ USA). Os dados (mm) foram analisados estatisticamente utilizando o teste T (p<0.05) e o teste de correlação de Pearson. Resultados: A diferença entre a posição de RC obtida pelos métodos na posição ântero-posterior diferiu estatisticamente de zero (p=0.001) e que não houve diferença significante (p=0,479) quando comparada as posições de RC em relação à linha média: UHM (0,56±0,35mm) e IHB (0,65±0,52mm). Não foi observada correlação linear de Pearson entre as medidas lineares antero-posteriores e laterais dos métodos estudados (r=0,26; p=0,268>0,05). Conclusão: Pode-se concluir que método GNF gerou uma retrusão mandibular maior que o método IC.

Objective: To compare, in the horizontal plane, the mandibular positions determined by two methods for registering the centric relation (CR): inclination of the head backward (IHB) and unstrained hinging movement (UHM), in edentulous patients. The null hypothesis was that there is not difference between the two methods. Material and Methods: Twenty edentulous subjects were selected for this study (n=20). All patients were manipulated to CR position using the methods IHB and UHM. The CR measure of each method was registered in one extraoral device, which was fixed at the maxillary and mandibular record bases. For each patient, the two CR positions were registered in the same extraoral device. To measure the anteroposterior and lateral linear variations between the points registered for each technique, it was used a profile projector (Model 6C, Nikon/USA). The data (μm) were statistically analyzed using the Tukey test (p<0.05) and Pearson correlation test. Results: The difference between CR position obtained by the methods in anteroposterior position differed statically from zero (p=0.001) and that there was no significant difference (p=0.479) when compared the CR positions with the medium line: UHM (0.56±0.35ìm) and IHB (0.65±0.52ìm). It wasn’t observed Pearson linear correlation between the anteroposterior and lateral linear measures of the methods (r = 0.26; p = 0.268>0.05). Conclusion: It can be conclude that the method UHM presented a higher mandibular retrusion than the method IHB.

Penetration of 35% hydrogen peroxide into the pulp chamber in bovine teeth after LED or Nd:YAG laser activation.

This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (light-emitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution. The optical density of this solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. The results were analysed using ANOVA and Tukey's test (5%). It was verified that the effect of activation was significant, as groups activated by LED or laser presented greater hydrogen peroxide penetration into the pulp chamber (0.499 +/- 0.622 microg) compared with groups that were not (0.198 +/- 0.218 microg). There was no statistically significant difference in the penetration of hydrogen peroxide into the pulp chamber between the two types of activation (LED or laser). The results suggest that activation by laser or LED caused an increase in hydrogen peroxide penetration into the pulp chamber.

Estudo comparativo entre dois métodos de aplicação de torque aos pilares protéticos em implantes de conexão externa / Comparative study between two methods of torque application on external hexagon implants abutments

O propósito do presente estudo foi avaliar o efeito do retorque na pré-carga de pilares protéticos fixados a implantes de conexão externa após diferentes tempos de espera. Trinta implantes de conexão externa (ScrewMaster®, Conexão) foram incluídos em resina acrílica. Sobre cada implante foi instalado um pilar protético(Ceraone®, Conexão) e, sobre estes, aparafusados os parafusos de fixação (30 Ncm), com o auxílio de um torquímetro digital. Os conjuntos implantes/pilares foram divididos em seis grupos, de acordo com os fatores "retorque" e "tempo de espera para coleta dos dados" (2, 5 e 10 min) (n = 5): aplicação de torque + coletade dados de destorque após 2 min (GA1), 5 min (GA2)e 10 min (GA3); aplicação de torque + retorque após10 min + coleta de dados de destorque após 2 min (GB1), 5 min (GB2) e 10 min (GB3). Os dados obtidos foram analisados estatisticamente pelos testes Anova (dois fatores) e Tukey (5%). As médias ± desvios-padrão dos valores de destorque (Ncm) observados para as condições experimentais foram: GA1: 25,39 ± 1,59; GA2: 22,91 ± 1,74; GA3: 21,95 ± 1,07; GB1: 28,16 ± 2,92; GB2: 21,97 ± 1,44; GB3: 21,21 ± 2,91. Verificou-se que os métodos de aplicação de torque (retorque) não influenciaram na perda de pré-carga para os grupos estudados (p = 0,6427 > 0,05) e que o tempo de espera para coleta dos dados do retorque afetou de maneira significativa os valores de pré-carga, sendo os maiores após 2 min da aplicação do torque (p = 0,0001 < 0,05). Conclui-se que houve perda significativa da pré-carga após 5 min da aplicação do torque.

The purpose of this study was to evaluate the effect of the retorquing on the preload of Ceraone abutment fixed to implants of external connection after different elapsed times for data collection. Thirty external hexagon implants (ConexãoTM, Brazil) were embedded in acrylic resin. After, the CeraoneTM abutments were fixed on each implant and the torque was applied (30Ncm). The sets of implant/abutment/screw were divided among six groups according to the factors “retorquing”and “elapsed times for data collection” (2, 5 and 10min) (n = 5): torque application + detorque data collection after 2min (GA1), 5min (GA2) and 10min (GA3) and torque application + new torque application (retorquing) after 10min + detorque data collection after 2min (GB1), 5min (GB2) and 10min (GB3). The data obtained were statistically analyzed by using the ANOVAtwo-way and Tukey test (5%). The means (± DP) of the detorque values (Ncm) observed for the experimental conditions were: GA1: 25.39 ± 1.59; GA2: 22.91± 1.74; GA3: 21.95 ± 1.07; GB1: 28.16 ± 2.92; GB2:21.97 ± 1.44; GB3: 21.21 ± 2.91. It was observed that the methods for torque application (retorquing) did not influence the lost of preload for the groups studied (p =0.6427 > 0.05) and that the elapsed time for retorquing data collection significantly affected the preload values,where the higher values were obtained after 2 min (p =0.0001 < 0.05) torque application. We concluded that regardless the methods used for torque application, there was a significant loss of preload after 5min torque application.

Efeito do tratamento de superfície do titânio comercialmente puro na resistência de união ao cisalhamento / Effect of the surface treatment of commercially pure titanium on the shear bond strength

Objetivo: Avaliar a resistência de união ao cisalhamento entre um material de revestimento estético e um metal submetido a três tratamentos de superfície. Método: Foram confeccionados trinta cilindros metálicos, com 5 mm de comprimento e 4mm de diâmetro cada, obtidos por meio de usinagem de barras de titânio comercialmente puro (Ticp). Os cilindros foram divididos em três grupos conforme o tratamento superficial (n=10): Grupo 1 - jateamento com óxido de alumínio (150 micrometros); Grupo 2 - Sistema Rocatec (3M/ESPE): jateamento com óxido de alumínio (Al2O3) 110 micrometros (Rocatec-pre powder) e com sílica (Rocatec-plus powder) + silano (Rocatec-Sil) e Grupo 3 - Sistema CoJet (3M/ESPE): jateamento com partículas de sílica 30 micrometros + Silano (ESPE Sil). Para confecção dos espécimes, foi aplicado sobre cada base metálica o sistema opaco (Sinfony Opaco, 3M ESPE/EUA) e posteriormente a resina composta para restauração indireta (Sinfony, 3M ESPE/EUA). Os espécimes foram armazenados em água destilada (37 graus Celsius / 24 horas) e submetidos ao ensaio de cisalhamento em máquina de ensaio universal (EMIC, modelo DL- 1000), com célula de carga de 500 Kgf, a uma velocidade constante de 0,5mm/min. Os dados obtidos (MPa) foram submetidos ao teste ANOVA (1 fator) e teste de Tukey (5%). Resultados: Observou-se que o grupo 1 (20,01 - 3,12) diferiu estatisticamente do grupo 2 (27,83 - 3,02) e do grupo 3 (26,91 - 3,65) que, entre si, não diferiram estatisticamente. Conclusão: O tratamento da superfície do Ticp com Rocatec ou CoJet gera maior resistência de união entre o Ticp e a resina Sinfony.

Objective: To assess the shear bond strength of an esthetic coatingmaterial and a metal subjected to three surface treatments. Methods: Thirty metallic cylinders (5 mm high x 4 mm diameter) were fabricated from machining of commercially pure titanium (CPTi) bars. The cylinders were assigned to three groups (n=10), according to the surface treatment: Group 1: 150- micrometrics aluminum oxide particle air abrasion; Group 2 - Rocatec system (3M/ESPE):110- micrometrics aluminum oxide particle air abrasion (Rocatec-pre powder) and silica air abrasion (Rocatec-plus powder) + silane (Rocatec- Sil); and Group 3 - CoJet system (3M/ESPE): 30- micrometrics silica particle air abrasion + silane (ESPE Sil). The specimens were fabricated by applying the opaque system (Sinfony Opaco, 3M/ESPE) followed by indirect composite resin (Sinfony, 3M ESPE/USA). After storage in distilled water at 37 degrees celsius for 24 hours, the specimens were tested in shear strength in a universal testing machine (EMIC, model DL- 1000) with a 500 kgf charge cell at 0.5 mm/min crosshead speed. The obtained data (MPa) were subjected to one-way ANOVA and Tukey's test at 5% significance level. Results: Group 1 (20.01 - 3.12) was statistically different from Group 2 (27.83 -3.02) and Group 3 (26.91 - 3.65). Groups 2 and 3 did not differ significantly from each other. Conclusion: The surface treatment of CPTi with Rocatec or CoJet produced greater bond strength between CPTi and Sinfony composite resin.