Rogério Margonar

Purpose: This in vitro study evaluated the adaptation and fracture resistance of screw- and cement-retained implant-supported restorations using lithium disilicate crowns cemented onto titanium bases and universal abutments of different heights.Methods: Thirty crowns were designed, milled, and divided into three groups: TBA (titanium base abutment - 4.7-mm-height and 4.65-mm-diameter), UA-4 (universal abutment - 4.0-mm-height and 4.5-mm-diameter), and UA-6 (universal abutment - 6.0-mm-height and 4.5-mm-diameter) (n=10). The abutments were placed in a mandibular first premolar model, torqued to 20 Ncm, and scanned using a digital intraoral scanner. The crowns were designed and fabricated using computer-aided design/computer-aided manufacturing technology. Adaptation was assessed using a stereomicroscope before and after ceramic sintering and after cementation with RelyX Ultimate resin cement. Fracture resistance was evaluated using a universal testing machine, and the failure modes were analyzed. The collected data were subjected to statistical analysis using one-way ANOVA and the Tukey least significant difference test (α=0.05).Results: The abutment type influenced restoration adaptation and fracture resistance. No differences in adaptation were found before or after luting (P > 0.05). However, after sintering, the TBA group exhibited smaller marginal gaps than the UA-4 (P = 0.0339) and UA-6 (P = 0.0006) groups. TBA showed a higher fracture resistance than UA-4 (P = 0.0093); no differences were observed between TBA and UA-6 or between UA-4 and UA-6 (P > 0.05). The UA-4 and UA-6 groups showed higher ceramic fracture rates, whereas the TBA group showed increased abutment deformation and ceramic fractures.Conclusions: The type and height of abutments influenced the fracture of screw-and-cement-retained implant-supported restorations.

This split-mouth randomized controlled trial aimed to evaluate the primary and secondary stability of hybrid implants with different thread configurations and hydrophilic surfaces. Twenty patients with a partially edentulous maxilla were selected. These patients received two types of implants with the same hydrophilic surface: CTP group: Cylindrical-Tapered implant with perforating threads; CTH: Cylindrical-Tapered implant with hybrid threads configuration (perforating and condensing threads). The primary and secondary stability parameters were measured by insertion torque and resonance frequency analysis at the time of implant placement and 7, 28, 56, and 90 days after the surgical procedure. The paired t-test was used to compare the data on the implant's stability between the groups. The statistical analysis was performed with a confidence level set at 95%. It was found that the implants in the CTH group presented higher primary stability values at the time of implant placement, due to the higher ISQ (63.61 ± 9.44 vs. 40.59 ±7.46) and insertion torque (36.92 ± 16.50 Ncm vs. 28.00 ± 14.40 Ncm), than the implants in the CTP group. The CTH group presented higher ISQ values in all follow-up periods: 7 days (68.67 ± 7.60 vs. 41.55 ± 9.07), 28 days (68.61 ± 5.98 vs. 47.90 ±13.10), 56 days (74.09 ± 3.96 vs. 55.85 ± 13.18), and 90 days (75.45 ± 4.02 vs. 63.47 ± 6.92) after implant placement. Hybrid implants with perforating and condensing threads demonstrated greater stability than hybrid implants with only perforating threads.

Objetivo: Comparar a estabilidade e perda óssea de implantes instalados no seio maxilar após elevação do seio maxilar utilizando Bio-ossä Small e Large, antes da carga funcional (T1) e após a mesma (T2). Métodos: Dez pacientes receberam enxerto ósseo no seio maxilar em duas granulações diferentes: Bio-ossä Small e Large, com uma granulação por seio. Após 8 meses, os implantes foram instalados. A confecção e instalação da prótese ocorreu após seis meses. De 10 pacientes, seis (13 implantes) foram selecionados, com média de idade de 53,4 anos. A estabilidade foi mensurada por meio da frequência de ressonância e todos os implantes instalados apresentaram valores elevados em ambos grupos. Resultados: A comparação entre os tempos mostrou diferença estatística com as partículas Bio-ossä Large, em que T1 (64,21±7,41) foi menor que T2 (69,96±4,95; P=0,003). No entanto, a comparação entre as diferentes dimensões de partículas no mesmo período não mostrou diferença estatística. Em relação à perda óssea marginal, não houve diferença estatística entre as dimensões das partículas. Não houve correlação entre estabilidade e perda óssea marginal e entre as diferentes dimensões das partículas do biomaterial. Conclusão: Os implantes instalados no seio maxilar enxertado com ambas as dimensões de partículas de Bio-Ossä apresentaram comportamento semelhante, permitindo estabilidade do implante e carga funcional.

Objective The study aimed to assess the angular and linear deviations of implants installed in mannequins aided by surgical guides produced with the techniques of dual tomography (DT), model-based tomography (MT), and nonprototyped guide. Materials and Methods Implants were installed in mannequins of a partially edentulous maxilla and divided into three groups: Group C (n = 20), implants installed using the conventional technique with flap opening and conventional guide; Group DT (n = 20), implants installed using guided surgery with the dual tomography technique; and Group MT (n = 20), implants installed using the model-based tomography technique. After implant installation, the mannequin was subjected to a computed tomography (CT) to measure the linear and angular deviations of implant positioning relative to the initial planning on both sides. Results There was a higher mean angular deviation in group C (4.61 ± 1.21, p ≤ 0.001) than in groups DT (2.13 ± 0.62) and MT (1.87 ± 0.94), which were statistically similar between each other. Similarly, the linear deviations showed group C with the greatest discrepancy in relation to the other groups in the crown (2.17 ± 0.82, p = 0.007), central (2.2 ± 0.77, p = 0.004), and apical (2.34 ± 0.8, p = 0.001) regions. Conclusion The techniques of DT and MT presented smaller angular and linear deviations than the conventional technique with the nonprototyped guide. There was no difference between the two-guided surgery techniques.

Este avaliou a influência da força ortodôntica em implantes submetidos a carga imediata. Para isso foram selecionados pacientes com ausência de dente posterior mandibular, que estão em tratamento ortodôntico cujo planejamento se faz necessário ancoragem esquelética. Os pacientes foram submetidos a cirurgia de instalação de implantes com conexão protética Cone Morse e torque de 45 N.cm. Em seguida, foi realizada a moldagem, confecção e instalação dos provisórios em infraoclusão. Em seguida, foram feitas as fixações ortodônticas de tubo duplo inferior de Edgewise / Ricketts e, em seguida, iniciada a mecânica dos arcos de acompanhamento para a verticalização dos molares, sustentados pelo implante com variação entre 50-150 g, por 6 meses. Foram realizadas análises perda óssea marginal e de frequência de ressonância (RFA) nos períodos T0 (imediatamente após a instalação do provisório) e T1 (180 dias). Foram selecionados 9 pacientes totalizando 10 implantes mandibulares. Porém apenas 5 implantes apresentaram estabilidade primária superior à 45N.cm. Na análise da perda óssea marginal, notou-se perda óssea de 1,21 ± 1,66 mm, sendo que não houve diferença estatisticamente significativa entre a região mesial (1,09 ± 1,6mm) e distal (1,34 ± 1,9mm) (P = 0.690). Já na análise RFA, houve diferença estatisticamente significativa entre os períodos T0 (67,3 ± 11,7) e T1 (76,8 ± 4,95) com valor de P=0,008. A força ortodôntica não interfere na estabilidade de implantes de carga imediata. Novos estudos com maiores períodos de acompanhamento e avaliação são necessários para se obter resultados mais consistentes.

O tratamento com implantes dentários tem evoluído significativamente desde a década de 70 até os dias atuais, tanto na questão de planejamento quanto na bioengenharia e tratamento da superfície desses implantes, com o objetivo de tornar o tratamento mais eficaz. Atualmente o uso de implantes imediatos tem sido cada vez mais estudado pelos pesquisadores e utilizado para a reabilitação oral dos pacientes. A literatura nos mostra que a inserção imediata de implantes dentários pós-extração é um tipo de tratamento com altas taxas de sucesso, possibilitando ao paciente ser submetido a apenas uma cirurgia, retorno à função mastigatória e estética mais rápidas. Para isso são necessários planejamento correto e seleção adequada do paciente para o sucesso do tratamento, levando em consideração a condição óssea e periodontal. O objetivo deste estudo é discorrer sobre o planejamento da reabilitação oral de uma paciente que foi submetida da extração dentária total dos dentes inferiores, instalação de 4 implantes dentários imediatos e confecção de uma prótese total com carga imediata do tipo protocolo.

The aim of this study was to evaluate the linear and angular deviations of the implants installed by the computerized tomography (CT)–guided surgery technique. Eighteen patients who underwent implant insertion by means of CT-guided surgery participated in this study. Ten of these patients had a fully edentulous maxilla, and 8 had a fully edentulous mandible. The patients received a total of 115 implants, of which 81 implants were installed in the maxilla and 34 installed in the mandible. Tomographic guides were made for tomographic examination in both the upper and lower jaws. After the image acquisition, the virtual planning of the positioning of the implants was performed in relation to the previously made prosthesis. The measurement of the linear and angular deviations between the virtual planning and the final position of the implants was performed with the overlap of the planning and postoperative tomography. There were no differences in the linear and angular deviations of the implants installed in the maxilla and mandible. Compared with the coronal region, there was a trend of greater linear deviations in the apical regions of the implants and a greater tendency toward deviations in the posterior regions than in the anterior regions of both arches. The CT-guided surgery promoted the installation of implants with high accuracy and allowed the installation of straight pillars in all cases evaluated. The linear deviations were not different in the different regions of the mouth or in the different portions of the implants.

The aim of this study was to investigate the effect of cyclosporine A (CsA) therapy on bone healing around osseointegrated implants in the rabbit by means of descriptive histologic and histomorphometric analyses. Eighteen rabbits received one implant each in the right tibia proximal metaphysis. After the bone-healing period of 3 months, 6 randomly selected animals were sacrificed (Group CTL-12) before the immunosuppression therapy initiation to obtain a standard of implant integration. Another six randomly selected animals were submitted to a daily subcutaneous (sc) injection of 10 mg/kg CsA (Group CsA) whereas the six remaining animals received daily sc injections of saline solution (Group CTL-24). Groups CTL-24 and CsA were sacrificed after another 12 weeks. Bone-to-implant contact (BIC), and bone area fraction occupancy (BAFO) within the implant threads were measured. Bone density (BD) and descriptive histological analyses were also accomplished. Rabbits under CsA therapy presented statistically lower percentage of BIC (33.28 ± 6.19) compared to the animals of CLT-24 (55.6 ± 17.73). No differences were found between CsA and CTL-12 (38.7 ± 7.87). Significant decreased percentage of BAFO between the implant threads in the CsA (48.43 ± 9.48) group compared to the CTL-24 (72.26 ± 11.72) was observed. No differences were found between CsA and CTL-12 (61.99 ± 13.94) groups. BD analysis showed significant lower BD in the CsA (48.56 ± 9.32) group compared to the CTL-12 (68.74 ± 10.89) and CTL-24 (77.96 ± 4.96) groups. Collectively, our findings demonstrated that CsA therapy negatively affect the bone healing around osseointegrated implants due to the significant lower values for BIC, BAFO, and BD.

Planejamento virtual em cirurgia guiada – uma realidade na Implantodontia - editoraplena.com.br