Biologic Behavior of Pressed Lithium Disilicate Ceramic and Zirconia on Human Gingival Fibroblasts: An In Vitro Study.

This study evaluated in vitro the biologic profile of manually polished surfaces of pressed lithium disilicate (LD) ceramic compared to zirconia (Zir) in human gingival fibroblasts. Samples with a 10-mm diameter and 3-mm thickness were used. After manual polishing, the average roughness (Ra) of the samples was measured. The cell proliferation and viability of gingival fibroblasts on the surfaces were assessed at 24, 48, and 96 hours. Additionally, the morphology, cell adhesion, and type III collagen (COLIII) and vimentin (VIM) expression by fibroblasts plated onto these surfaces was analyzed. Polystyrene (Pol) was used as control for all assays. The mean Ra was 0.261 ± 0.053 µm for Zir and 0.345 ± 0.130 µm for LD. Both surfaces presented similar cell proliferation and viability (P > .05). The cell morphology demonstrated that, for both surfaces, the cells were occasionally spindle-shaped, parallel to the direction of the grooves. Compared to Pol, an upregulation of COLIII and VIM gene expression was observed by fibroblasts cultured on Zir and LD at all time points (P < .05). The characteristics presented by LD and Zir surfaces after manual polishing protocol were similar and had biologically favorable performances, thus suggesting LD as a suitable alternative to Zir in the peri-implant region for esthetic purposes.

Remodeling of calvarial graft in increased atrophic maxillary thickness. A prospective clinical study.

PURPOSE: This study evaluated the autogenous graft resorption rate in a calvarial block graft in the anterior region of an atrophic maxilla and compared it with the thickness of the remaining ridge. MATERIALS AND METHODS: Twelve patients were included in the study. They were submitted to cranial calotte graft surgery, and there were 40 blocks in total. The thicknesses of the ridges in the crest, middle and apical regions of the blocks were evaluated by computed tomography scan at the times: preoperative (T0), 48 hours (T1) and 6 months (T2) after the reconstructions. RESULTS: The resorption of the blocks from T1 to T2 was 13.4%. The greatest remodeling occurred in the alveolar bone crest (20.07%), followed by the middle portion (12.28%), and the apical region (9.5%), but the three regions did not significantly differ between times T1 and T2 (crest P = .07, middle P = .124, apical P = .131). Recipient site with the lowest thickness had the greatest resorption rates (up to 2 mm = 17.6%; from 2 to 4 mm = 17.52%) while than those with a thickness greater than 4 mm had a mean resorption of 8.81%. CONCLUSIONS: The resorption of the grafts in this study was 13.4%. Higher resorption rates were observed in the alveolar crest areas, where the ridges were less thick.

Preservation of Dental Sockets Filled with Composite Bovine Bone. A Single-Blind Randomized Clinical Trial.

The purpose of this study was to evaluate the preservation of alveolar dimensions in human fresh extraction sockets filled with a composite bovine bone graft by means of design of single-blind randomized clinical trial. Forty participants had monoradicular teeth extracted (one teeth in each participant), and after were randomly divided into 2 groups: individuals whose fresh sockets were filled with the composite heterologous bone graft (Biomaterial Group), or with blood clot (Control Group). After extraction, the fresh sockets were measured at their greatest mesiodistal (MD) and bucco-lingual/palatal (BL/P) distance. Primary closure of the soft tissue was performed with a fibro-mucosal plug. After 120 post-operative days, the re-entry procedure was performed and the largest MD and BL/P measurements were again obtained to calculate the remodeling of the alveolar bone measured in percentage. In the biomaterial group, a percentage reduction of 1.62% and 3.29% in the MD and BL/P dimensions was observed 120 days after the extractions, whereas a reduction of 4.97% and 7.18% in the MD and BL/P dimensions occurred in the control group. There was a statistically significant difference (p<0.05) between the two groups for the bucco-palatal and mesiodistal measurements in the maxilla. In view of the results obtained, it can be concluded that composite bovine bone graft limited but did not impede alveolar bone remodeling.

Preservation of dental sockets filled with composite bovine bone. A single-blind randomized clinical trial

Abstract The purpose of this study was to evaluate the preservation of alveolar dimensions in human fresh extraction sockets filled with a composite bovine bone graft by means of design of single-blind randomized clinical trial. Forty participants had monoradicular teeth extracted (one teeth in each participant), and after were randomly divided into 2 groups: individuals whose fresh sockets were filled with the composite heterologous bone graft (Biomaterial Group), or with blood clot (Control Group). After extraction, the fresh sockets were measured at their greatest mesiodistal (MD) and bucco-lingual/palatal (BL/P) distance. Primary closure of the soft tissue was performed with a fibro-mucosal plug. After 120 post-operative days, the re-entry procedure was performed and the largest MD and BL/P measurements were again obtained to calculate the remodeling of the alveolar bone measured in percentage. In the biomaterial group, a percentage reduction of 1.62% and 3.29% in the MD and BL/P dimensions was observed 120 days after the extractions, whereas a reduction of 4.97% and 7.18% in the MD and BL/P dimensions occurred in the control group. There was a statistically significant difference (p<0.05) between the two groups for the bucco-palatal and mesiodistal measurements in the maxilla. In view of the results obtained, it can be concluded that composite bovine bone graft limited but did not impede alveolar bone remodeling.

Resumo O objetivo deste estudo foi avaliar em humanos a manutenção do volume em alvéolos frescos preenchidos por osso integral de origem bovina por meio de um estudo clínico randomizado com monocegamento. Quarenta dentes uni radiculares foram extraídos em 40 pacientes (um dente em cada participante), e apos estes pacientes foram divididos aleatoriamente em 2 grupos: indivíduos que tiveram o alvéolo fresco preenchido por osso integral de origem bovina (Grupo Biomaterial) ou por coagulo sanguíneo (Grupo Controle). Apos a exodontia os alvéolos foram medidos em suas maiores distancias mesio-distal (MD) e vestíbulo lingual/palatina (VL/P) por meio de compasso de ponta seca. O fechamento primário dos alvéolos foi realizado com um tampão fibromucoso. Apos 120 dias pós-operatórios durante o procedimento de reabertura foram obtidas novamente as maiores medidas MD e VL/P para calcular em porcentagem o nível de remodelação do osso alveolar. No grupo biomaterial observou-se uma redução em porcentagem de 1,62% e 3,29% nas medidas MD e VL/P 120 dias apos as extrações, enquanto no grupo controle houve uma redução de 4,97% e 7,18% nas medidas MD e VL/P no mesmo período. Houve diferença estatisticamente significante (p<0,05) entre os dois grupos para as medidas vestíbulo/palatina e mesiodistal na maxila. Diante dos resultados obtidos conclui-se que o osso integral de origem bovina limitou, mas não impediu a remodelação óssea alveolar.

Novo componente de transferência para implantes. Estudo in vitro / New transfer component for dental implants. In vitro study

Os autores avaliaram, em um microscópio eletrônico de varredura (MEV), a precisão da moldagem de transferência de implantes de hexágono externo por meio de um novo modelo de transferente, comparando-o com a técnica do transferente quadrado. Foram realizadas 40 moldagens, 20 com componente de transferência quadrado (grupo-controle) e 20 com o componente de transferência implant smart transfer ­ IST (grupo-teste), a partir de um modelo acrílico padronizado com três réplicas de implantes de hexágono externo posicionados na região posterior, simulando uma condição clínica em mandíbula. Uma estrutura metálica padrão em liga de titânio foi parafusada sobre os análogos dos modelos obtidos sob torque de 10 Ncm. Foram realizadas leituras na face vestibular e na face lingual do conjunto análogo/estrutura padrão, tendo a posição central como ponto de eleição. Os resultados foram analisados estatisticamente (p-valor=0,05) e, embora tenham havido diferenças médias entre os grupos, as mesmas não foram estatisticamente significantes. Foi possível concluir que não existe diferença na precisão das moldagens de implantes realizadas com componente de transferência quadrado e o modelo implant smart transfer para prótese parcial fixa.

The authors evaluated by scanning electron microscopy (SEM), precision impression transfer of external hex implants through a new transfer model by comparing it with the technical square transfer. Fourty impressions were made; 20 with square transfer component (control) and 20 with the IST transfer component (test) from a standard acrylic model with three external hexagon implant replicas positioned in the posterior region simulating a clinical jaw condition. A titanium framework was screwed onto the implant analogs with a 10 Ncm torque. Three measurements were performed on the buccal aspect and three on the lingual surface, with the middle position as election point. The results were analyzed statistically (p=0.05), although there have been average differences between the groups, they were not statistically significant. It was concluded there was no difference in the accuracy of impression made with square transfer component and implant smart transfer model for fixed partial dentures.

Aumento ósseo vertical com instalação simultânea de implante dentário pela técnica Bone Ring ­ acompanhamento clínico de dois anos / Vertical bone augmentation with simultaneous placement of dental implant using the bone ring technique ­ a 2-year clinical follow-up

Os procedimentos de enxertia óssea para ganho vertical ainda são temerários na Implantodontia. Não há um consenso na literatura sobre as técnicas para aumento em altura da crista óssea alveolar para futura colocação de implantes. Além disso, o tempo de tratamento é demasiadamente prolongado quando são realizadas as técnicas de enxerto ósseo com implantação tardia. Sendo assim, o objetivo deste trabalho foi descrever uma técnica para aumento ósseo vertical simultâneo à instalação de implante denominado bone ring. Paciente apresentando severo defeito ósseo em altura e largura na região do dente 14 foi reabilitada a partir da reconstrução óssea tridimensional com anel ósseo removido da área mentual e implantação imediata à fixação do enxerto. Após seis meses, foram realizados a reabertura e procedimentos protéticos de personalização de perfil de emergência, com posterior instalação de coroa metalocerâmica. Decorridos dois anos de acompanhamento, notou-se estabilidade tecidual peri-implantar sem remodelações severas do tecido ósseo peri-implantar. Pôde-se concluir que a técnica de reconstrução óssea tridimensional simultânea à instalação de implante ­ bone ring ­ é uma alternativa viável, mediante rigoroso planejamento e curva de aprendizado indicada para defeitos ósseos severos.

Bone grafting procedures for vertical bone augmentation are still an issue on implant dentistry. There is no literature consensus regarding techniques for alveolar ridge height increase for further implant placement. Besides, treatment times are extended in case of delayed implant placement. The aim of this paper was to describe a technique for vertical bone augmentation at the same time of implant installation (bone ring). A patient having a several bone defect in height and width at the region of tooth 14 received a 3D reconstruction with a bone ring removed from the chin area. Six months later, implant exposure was performed with procedures for soft tissue conditioning and delivery of a metalloceramic restoration. Tissue stability and no significant bone remodeling were observed after two years. The proposed technique for three-dimensional reconstruction ­ bone ring ­ is a viable alternative provided that judicious treatment planning and considerable learning curve are observed to manage severe bone defects.

In vitro analysis of the microbiological sealing of tapered implants after mechanical cycling.

OBJECTIVE: The aim of this in vitro study was to evaluate the mechanical behavior and bacterial microleakage at the implant/abutment-tapered interface following mechanical cycling. MATERIALS AND METHODS: Two groups of screwless (Morse taper) implants (G1 and G2) and two groups of prosthetic screwed implants (G3 and G4) were tested. One group from each model (G2 and G4) were submitted to mechanical cycling, 500,000 cycles per sample, at a load of 120 N at 2 Hz prior to analysis. Microbiological analysis was performed via immersion of all samples in an Escherichia coli-containing suspension, incubated at 37 °C. After 14 days, the abutments were removed from their respective implants, registering the removal force (G1 and G2) or reverse torque (G3 and G4), and the presence of bacterial leakage was evaluated. Scanning electron microscopy (SEM) was performed to analyze the tapered surfaces of the selected samples. The Student t, binomial, and G tests were used for statistical analysis at a 5 % significance level. RESULTS: The results showed no significant difference between removal force, reverse torque, and contamination values when comparing implants of the same type. However, when the four groups were compared, contamination differed significantly (p = 0.044), with G1 having the least number of contaminated samples (8.3 %). SEM analysis showed superficial defects and damage. CONCLUSIONS: The abutment removal force or torque was not affected by mechanical cycling. Bacterial sealing of the implant/abutment tapered interface was not effective for any condition analyzed. Imprecise machining of implant parts does not allow a sufficient contact area between surfaces to provide effective sealing and prevent bacterial leakage. CLINICAL RELEVANCE: The microscopic gap caused by unsatisfactory implant/abutment adaptation, surface irregularities, and plastic deformation of all parts enabled bacterial contamination of the oral implants.

Implantação e carregamento imediato unitário na região posterior ­ relatos de casos clínicos com acompanhamento de um a quatro anos / Immediate placement and loading of single-tooth implants in the posterior region ­ case reports with 1-4 years of follow-up

O objetivo deste trabalho foi apresentar três casos clínicos de implantação imediata com provisionalização imediata, empregando a filosofia one abutment at one time. Nos três casos clínicos, após a realização das imagens tomográficas e prescrição medicamentosa, os implantes foram posicionados nas raízes mesiais (molares inferiores) e distovestibulares (molares superiores), sendo o espaço remanescente preenchido com biomaterial para preservação alveolar. Após a colocação dos pilares defi nitivos, coroas provisórias permaneceram por 90 dias até a cimentação das coroas metalocerâmicas definitivas. Os implantes são colocados abaixo do nível da crista óssea e o pilar utilizado constitui um exemplo de platform switching, que cria um espaço biológico e uma zona de selamento. Os controles destes casos vão de um a quatro anos demonstrando excelente estabilidade dimensional. Os resultados clínicos sugerem que a osseointegração de implantes unitários imediatamente carregados na região posterior pode ser alcançada. O uso de uma restauração provisória com a anatomia ideal de um dente molar pode facilitar a formação de contornos naturais da mucosa peri-implantar. É importante que o paciente não apresente bruxismo, possua osso suficiente para o posicionamento do implante e que pratique uma boa higiene oral.

The aim of this paper was to present three clinical cases with immediate implant insertion and provisionalization using the one abutment one time philosophy. On these, after CBCT and medicament prescription, the implants were positioned at the mesial (mandibular molars) and at the alveolar center (maxillary molars) aspects, being the gaps and the alveoli filled with a biomaterial for alveolar preservation. After the definitive abutments being placed, the provisional crowns remained in position for 90 days until cementation of the definitive metalloceramic crowns. The implants are placed below the bone crest level and the prosthetic abutment forms a platform-switching which creates a biologic space and a sealing zone. The follow-ups range from 1 to 4 years demonstrating excellent dimensional stability. The clinical results suggest that the osseointegration of immediate, single-tooth implants at the posterior region can be achieved. The use of a provisional restoration with ideal characteristics of a molar tooth facilitates the peri-implant mucosa contouring. It is important to select symptom-free bruxism patient, with sufficient bone for implant placement, and having good oral hygiene levels.

Effect of mechanical cycling on screw torque in external hexagon implants with and without platform switching.

This in vitro study evaluated the effect of mechanical cycling on the torque of retaining screw in external hexagon implants with platform switching (PS), regular platform (RP) and wide platform (WP). A total of 30 specimens were equally divided into 3 groups: PS, PR and WP. Each specimen was prepared with implants: 3.75 x 10 mm for RP group and 5.0x10 mm for PS and WP groups and its respective abutment with 32 Ncm torque. All groups were subjected to 106 cycles with 100 N (corresponding to about 40 months of chewing). The results were obtained with the reverse torque of each specimen and data were evaluated using ANOVA and Tukey test (p<0.05). The PS group showed statistically significant difference in screw removal torque (30.06±5.42) compared with RP (23.75±2.76) and WP (21.32±3.53) (p<0.05) groups; the RP and WP groups showed no statistically significant difference between them. It was concluded that the PS group showed higher reverse torque value, suggesting lower susceptibility of the abutment screw loosening.

Effect of Mechanical Cycling on Screw Torque in External Hexagon Implants with and without Platform Switching

This in vitro study evaluated the effect of mechanical cycling on the torque of retaining screw in external hexagon implants with platform switching (PS), regular platform (RP) and wide platform (WP). A total of 30 specimens were equally divided into 3 groups: PS, PR and WP. Each specimen was prepared with implants: 3.75 x 10 mm for RP group and 5.0x10 mm for PS and WP groups and its respective abutment with 32 Ncm torque. All groups were subjected to 106 cycles with 100 N (corresponding to about 40 months of chewing). The results were obtained with the reverse torque of each specimen and data were evaluated using ANOVA and Tukey test (p<0.05). The PS group showed statistically significant difference in screw removal torque (30.06±5.42) compared with RP (23.75±2.76) and WP (21.32±3.53) (p<0.05) groups; the RP and WP groups showed no statistically significant difference between them. It was concluded that the PS group showed higher reverse torque value, suggesting lower susceptibility of the abutment screw loosening.

Este estudo in vitro avaliou o efeito da ciclagem mecânica no torque dos parafusos de retenção em implantes de hexágono externo com plataforma switching (PS), plataforma regular (RP) e plataforma larga (WP). Foram utilizados 30 corpos de prova divididos em 3 grupos equitativamente: PS, RP e WP. Cada corpo de prova foi preparado com implantes: 3,75x10 mm para o grupo RP e 5,0x10 mm para os grupos PS e WP, e seu respectivo abutment com o torque de 32 Ncm. Todos os grupos foram submetidos a 106 ciclos com 100 N de força (o que corresponde a aproximadamente 40 meses de mastigação). Os resultados foram obtidos com o torque reverso de cada espécime e os dados foram avaliados com ANOVA comparado com o teste de Tukey (p<0,05). O grupo PS apresentou diferença estatisticamente significante no torque de remoção do parafuso (30,06±5,42) comparado com os grupos RP (23,75±2,76) e WP (21,32±3,53) (p<0,05); os grupos RP e WP não apresentaram diferença estatisticamente significante entre si. Concluiu-se que o grupo PS apresentou maior valor de torque reverso sugerindo menor susceptibilidade de afrouxamento do parafuso de fixação do abutment.

Reconstrução de rebordo alveolar com enxerto de tecido conjuntivo subepitelial pediculado para obtenção de um correto perfil de emergência peri-implantar. Acompanhamento de cinco anos / Alveolar ridge augmentation with subepithelial connective tissue graft pedicle to achieve a correct peri-implant emergence profi le. A five year follow-up

As reabilitações assistidas sobre implantes necessitam do planejamento não só da fixação do implante no interior do tecido ósseo, mas também do planejamento da futura margem gengival. Tendo em vista a presença comum de defeitos anatômicos em pacientes edêntulos, este caso clínico teve como objetivo demonstrar a aplicação de uma técnica de correção de deficiências teciduais em zona estética, por meio de enxerto de tecido conjuntivo subeptelial rotacionado do palato. Um paciente de 39 anos de idade, com ausências nas regiões 11 e 21, foi submetido à fixação de dois implantes de hexágono externo pela técnica mediata. Na reabertura, foi planejado o enxerto de tecido conjuntivo pediculado (técnica do rolo modificada) para melhoria do suporte tecidual vestibular e favorecimento do perfil de emergência das coroas protéticas. Após cinco anos de acompanhamento, o enxerto de tecido conjuntivo subepitelial pediculado mostrou boa estabilidade na manutenção da espessura vestibular e margem peri-implantar. Este acompanhamento clínico de cinco anos permitiu concluir que o enxerto de tecido conjuntivo subepitelial pediculado pode promover e manter a melhoria do contorno tecidual em zona peri-implantar a longo prazo.

Implant-assisted oral rehabilitations require not only the planning of implant fixation within the bone tissue as well as planning for future soft tissue margin. Given the common presence of anatomical defects in edentulous patients, this clinical case aimed to demonstrate the application of a technique for correction of tissue defects in the esthetic zone, through the use of a subepithelial connective tissue graft rotated from the palate. A 39 years-old patient presented with partial edentulism at regions 11 and 21 was treated with two external hex dental implants. The second-stage surgery was planned and a pedicle tissue graft (modified roll technique) to improve the buccal tissue support and to enhance the emergence profile of prosthetic crowns was performed. After 5 years of follow-up, the graft still shows good stability maintaining labial thickness and the peri-implant margins. It can be concluded that the subepithelial connective tissue graft can promote and maintain tissue contours at the peri-implant zone over the long-term.

Avaliação da preservação de membrana sinusal após técnica de abordagem lateral do seio maxilar com trefina / Preservation of maxillary sinus membrane using a lateral approaching trephine technique

O objetivo deste trabalho foi relatar 12 casos clínicos, realizados com a técnica de abordagem lateral para acesso ao seio maxilar utilizando as trefinas do kit SLA (sinus lateral approach), Neobiotech (Seul, Coreia). Foram selecionados 12 pacientes, com indicação para cirurgia de elevação de seio maxilar para instalação de implantes, na qual a osteotomia da parede lateral do seio foi executada com as trefinas C-Reamer e LS-Reamer acopladas ao contra-ângulo cirúrgico. O desenho das arestas de corte das trefinas foi desenvolvido para reduzir o risco de fenestração da membrana sinusal, complicação mais frequente neste tipo de cirurgia. Esta técnica proporcionou uma osteotomia facilitada e precisa um acesso conservador e uma fresagem segura, sem rompimento da membrana sinusal nos 12 casos operados. As cirurgias foram executadas por operadores com diferentes níveis de experiência, com resultados semelhantes ao final do procedimento.

The aim of this study is to report twelve cases were performed using the lateral approach technique for access to the maxillary sinus with trephines – SLA (sinus lateral approach) kit Neobiotech (Seoul, Korea). We selected twelve patients indicated for surgical elevation of the maxillary sinus for implant placement, which osteotomy of the lateral wall of the sinus was performed with the trephine C-Reamer and LS-Reamer coupled to the surgical hand-piece. The design of the cutting edges of the trephine was developed to reduce the risk of fenestration of the sinus membrane, the most common complication in this kind of surgery. This technique provided an easier osteotomy and accurate access to a conservative and safe milling, without disruption of the sinus membrane in all twelve cases operated. The surgeries were performed by different experience levels operators with similar results after the procedure.

Avaliação microscópica da propriedade biológica e da biocompatibilidade do osso composto e do osso integral de origem bovina / Microscopic evaluation of biological properties and biocompatibility of bovine, non-demineralized lyophilized and composite bovine bones

Este trabalho teve como objetivo avaliar a propriedade biológica e a biocompatibilidade do osso composto e do osso integral de origem bovina, implantados em cavidades ósseas de tíbias e no plano subcutâneo de ratos. Foram utilizados 24 ratos sacrificados após 15 e 45 dias. Os resultados do exame microscópico das peças obtidas do subcutâneo mostraram aos 15 dias uma reação inflamatória ao redor das partículas do material com presença de células gigantes e, aos 45 dias, observou-se diminuição da reação inflamatória e presença de tecido conjuntivo fibroso ao redor das partículas com a presença de células gigantes. Não houve indícios de formação óssea ectópica nas peças histológicas obtidas da tíbia; foi possível observar maior atividade de neoformação óssea no grupo controle aos 15 dias com 42,8% da cortical externa sendo neoformada em comparação aos 22,6% do grupo Orthogen e 25% do grupo GenMix. Aos 45 dias havia 62,5% de neoformação óssea no grupo controle, 26% no grupo Orthogen e 35% no grupo GenMix. Pôde-se concluir que o osso composto e o osso integral de origem bovina são materiais biocompatíveis, possibilitam a neoformação óssea por suas qualidades osseocondutivas e não induzem à formação de osso ectópico...

The aim of this study was to evaluate the biological properties and biocompatibility of bovine non-demineralized lyophilized and composite bones implanted in tibiae bone cavities and at the subcutaneous level. Twenty-four rats were used and sacrificed 15 and 45 days later. At the subcutaneous level, after 15 days an inflammatory reaction was seen around biomaterial particles with the presence of giant cells and at 45 days fibrous connective tissue had also developed. No signs of ectopic bone formation were observed at tibiae regions; more bone neoformation was observed at the control group (15 days) with 42.8% of the outer cortex layer against 22.6% at Orthogen and 25% at GenMix groups. At 45 days, correspondent values for bone neoformation were 62.5% at control, 26% at Orthogen, and 35% at GenMix groups, respectively. It can be concluded that both materials tested were biocompatible aiming to bone neoformation by their osteoconductive properties with no ectopic formation sites observed...

Utilização de stopper de fresas em Implantodontia: avaliação por meio de questionário / The use of stopper drills for dental implant surgery

A fresagem óssea para instalação de implante é um procedimento de alta precisão, onde o planejamento adequado e a atenção aos detalhes são fundamentais para o sucesso do procedimento cirúrgico, principalmente quando executada próxima a áreas nobres, como o nervo alveolar inferior. Esta situação tornou-se mais frequente, devido à utilização dos implantes curtos. Durante a cirurgia, a mistura de soro, saliva e sangue, associados à localização do implante a ser instalado e à velocidade de rotação da fresa pode, mesmo com as melhores condições de iluminação, pode ser difícil saber quando uma determinada profundidade foi atingida. O objetivo neste trabalho foi avaliar o uso do stopper pelos dentistas, por meio de questionário, analisando sua necessidade, dificuldades, praticidade, rapidez e segurança de seu uso, considerando as motivações para o uso ou não deste dispositivo. Foi elaborado um questionário com dez questões e aplicado a 128 profissionais que executam cirurgia para instalação de implantes sem prévia orientação sobre o assunto. Os dados foram submetidos à análise descritiva com resultados em números absolutos e porcentagens. Nos resultados, 20,3% dos profissionais relataram que já tiveram histórico de parestesia do nervo alveolar inferior devido à fresagem, 58,5% nunca usaram nenhum tipo de dispositivo limitador de profundidade e 17,5% dos profissionais relataram desconhecer o dispositivo. Pôde-se concluir que, embora os profissionais tenham a percepção de que o stopper de fresas é um acessório importante durante a cirurgia, a sua utilização é pouco difundida, o que pode estar associado aos altos índices de complicações relatados neste estudo.

Bone drilling for installation of implant is a procedure of high accuracy in which the proper planning and attention to details are key to the success of the surgical procedure, especially when drilling is done next to noble structures as the inferior alveolar nerve. This situation is becoming increasingly frequent due the increased use of short implants. During the surgery, the mixture of saline solution, saliva and blood, associated with the location of the implant to be installed and cutter rotational speed, can even under the best lighting conditions make it difficult to know exactly when a given depth. The objective of this study was to evaluate the use of stopper by dentists through the questionnaire, analyzing your needs, difficulties, convenience, speed and safety of its use, considering what the motivations for use of this device or not. A questionnaire was developed consisting of ten questions and applied to 128 practitioners who perform surgery to implant placement without prior guidance on the subject. The data were submitted to descriptive analysis of absolute numbers and percentages. In the results reported that surgeons had 20.3% cases of inferior alveolar nerve paresthesia due to milling, 58.5% never used any kind of depth limiting device and 17.5% of professionals reported that do not know the device. It can be concluded that although professionals have the perception that the stopper is a drill accessory important during surgery, their use is not very wide spread, which may be associated with high complication rates reported in this study.

Evaluation of stress patterns produced by implant-retained overdentures and implant-retained fixed partial denture.

The purposes of this study were to photoelastically measure the biomechanical behavior of 4 implants retaining different cantilevered bar mandibular overdenture designs and to compare a fixed partial denture (FPD). A photoelastic model of a human edentulous mandible was fabricated, which contained 4 screw-type implants (3.75 × 10 mm) embedded in the parasymphyseal area. An FPD and 3 overdenture designs with the following attachments were evaluated: 3 plastic Hader clips, 1 Hader clip with 2 posterior resilient cap attachments, and 3 ball/O-ring attachments. Vertical occlusal forces of 100 N were applied between the central incisor and unilaterally to the right and left second premolars and second molars. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. The results showed that the anterior loading, the overdenture with 3 plastic Hader clips, displayed the largest stress concentration at the medium implant. With premolar loading, the FPD and overdenture with 3 plastic Hader clips displayed the highest stresses to the ipsilateral terminal implant. With molar loading, the overdenture with 3 ball/O-ring attachments displayed the most uniform stress distribution in the posterior edentulous ridge, with less overloading in the terminal implant. It was concluded that vertical forces applied to the bar-clip overdenture and FPD created immediate stress patterns of greater magnitude and concentration on the ipsilateral implants, whereas the ball/O-ring attachments transferred minimal stress to the implants. The increased cantilever in the FPD caused the highest stresses to the terminal implant.

Influence of different base thicknesses on maxillary complete denture processing: linear and angular graphic analysis on the movement of artificial teeth.

OBJECTIVE: The purpose of this study was to compare the dental movement that occurs during the processing of maxillary complete dentures with 3 different base thicknesses, using 2 investment methods, and microwave polymerization. METHODS: A sample of 42 denture models was randomly divided into 6 groups (n = 7), with base thicknesses of 1.25, 2.50, and 3.75 mm and gypsum or silicone flask investment. Points were demarcated on the distal surface of the second molars and on the back of the gypsum cast at the alveolar ridge level to allow linear and angular measurement using AutoCAD software. The data were subjected to analysis of variance with double factor, Tukey test and Fisher (post hoc). RESULTS: Angular analysis of the varying methods and their interactions generated a statistical difference (P = 0.023) when the magnitudes of molar inclination were compared. Tooth movement was greater for thin-based prostheses, 1.25 mm (-0.234), versus thick 3.75 mm (0.2395), with antagonistic behavior. Prosthesis investment with silicone (0.053) showed greater vertical change compared with the gypsum investment (0.032). There was a difference between the point of analysis, demonstrating that the changes were not symmetric. CONCLUSIONS: All groups evaluated showed change in the position of artificial teeth after processing. The complete denture with a thin base (1.25 mm) and silicone investment showed the worst results, whereas intermediate thickness (2.50 mm) was demonstrated to be ideal for the denture base.

Mobility, aesthetic, implants, and satisfaction of the ocular prostheses wearers.

During the process of facial rehabilitation, the mobility of ocular prostheses must be considered. Whereas some factors depend exclusively on the dentist, such as molding techniques and selection of material for denture construction, regarding ocular rehabilitation, factors, such as type of surgery, whether to adopt implants, and the use of lubricants, deserve special attention owing to their integration and their association with other factors pertaining exclusively to the patient. To establish harmony, and with the intention of aiding the dentist, after a discerning evaluation, the authors of this study report the factors that provide greater or less mobility to ocular prostheses and conceal the prosthesis in a more natural way, thereby contributing toward achieving a favorable aesthetic result in rehabilitations.

Effect of different repair techniques on the accuracy of repositioning the fractured denture base.

OBJECTIVE: This study investigated the efficacy of different techniques for the union of fragments of a denture before repair and on the accuracy of the reposition. MATERIALS AND METHODS: For this study, 20 maxillary dentures made with Lucitone 550 heat-cured resin were used. Points were determined with a scanner on the cusp of the teeth, as a measurement of the segments. After digitisation, each model was exported to the AUTOCAD R 14 program and two-dimensional measurements of the distances between the marked points were made. After the initial analysis, the dentures were fractured into two segments using an impact test machine. For the repair, maxillary dentures were divided into two groups; in the first, the repair was carried out using Kerr's sticky wax and in the second group, Super Bonder was used to join the fragments, with subsequent inclusion of DENTSPLY Repair Material resin. After the repair, the points of the maxillary dentures were measured again. The numerical values obtained were tabulated to compare the measurements before fracture and after the repair. For statistical analysis, analysis of variance was employed, using a single factor and double factor, followed by the Tukey test with a reliability of 95%. RESULTS: The results demonstrated a statistically significant difference between the materials used to join the dentures for repair, where the dentures were joined with sticky wax presented a larger variation in the distances between the points. CONCLUSION: The variation in distances between the points is influenced by the agent of repair.

A modified method of immediate occlusal loading using a reinforced framework denture: a case report.

The technique presented in this article presents a protocol for treatment that reduces the time required for the fabrication and placement of an implant supported prosthesis. It also offers improved patient comfort at a lower cost when compared to conventional technology.

Effect of flasking and polymerization techniques on tooth movement in complete denture processing.

PURPOSE: The purpose of this study was to compare the artificial tooth positional changes following the flasking and polymerization of complete dentures by a combination of two flasking methods and two polymerization techniques using computer graphic measurements. MATERIALS AND METHODS: Four groups of waxed complete dentures (n = 10) were invested and polymerized using the following techniques: (1) adding a second investment layer of gypsum and conventional water bath polymerization (Control), (2) adding a second investment layer of gypsum and polymerization with microwave energy (Gypmicro), (3) adding a second investment layer of silicone (Zetalabor) and conventional polymerization (Silwater), and (4) adding a second investment layer of silicone and polymerization with microwave energy (Silmicro). For each specimen, six segments of interdental distances (A to F) were measured to determine the artificial tooth positions in the waxed and polymerized stages using software program AutoCad R14. The mean values of the changes were statistically compared by univariate ANOVA with Tukey post-hoc test at 5% significance. RESULTS: There were no significant differences among the four groups, except for segment D of the Silmicro group (-0.004 +/- 0.032 cm) in relation to the Gypwater group (0.044 +/- 0.031 cm) (p < 0.05), which presented, respectively, expansion and shrinkage after polymerization. CONCLUSIONS: Within the limitations of this study, it was concluded that although the differences were not statistically significant, the use of a silicone investment layer when flasking complete dentures resulted in the least positional changes of the artificial teeth regardless of the polymerization technique.