15-Year Retrospective Study on the Success Rate of Maxillary Sinus Augmentation and Implants: Influence of Bone Substitute Type, Presurgical Bone Height, and Membrane Perforation during Sinus Lift.

Objectives: To evaluate the success rate of bone grafts and implants carried out at the Latin American Institute for Research and Dental Education (ILAPEO), considering the following: (i) the different pure bone substitutes (autogenous, xenogeneic, and alloplastic), (ii) the presurgical bone height, and (iii) how the treatment is compromised when membrane perforation occurs during sinus lift in maxillary sinus surgeries. Material and Methods. The initial sample comprised 1040 records of maxillary sinus lifting surgeries. After evaluation, the final sample retained 472 grafts performed using the lateral window technique with a total of 757 implants. The grafts were divided into 3 groups: (i) autogenous bone (n = 197), (ii) xenogenous bovine bone (n = 182), and (iii) alloplastic material (n = 93). One calibrated examiner classified the sample into two groups based on the residual bone height (<4 mm and ≥4 mm) of the area of interest measured on parasagittal sections of tomographic images. Data on membrane perforation occurrences in each group were collected; qualitative variables were described using frequency, expressed as percentages. The Chi-square test was used to analyze the success of the graft types and the survival rate of the implants as a function of the grafted material and the residual bone height. The Kaplan-Meier survival analysis was used to calculate the survival rate of bone grafts and implants according to the classifications adopted in this retrospective study. Results: The success rate of grafts and implants was 98.3% and 97.2%, respectively. There was no statistically significant difference in the success rate among the different bone substitutes (p = 0.140). Only 8 grafts (1.7%) and 21 implants (2.8%) failed. There was a greater success rate for both grafts (96.5%) and implants (97.4%) when the bone height was ≥4 mm. The success rate in the 49 sinuses in which the membrane was perforated was 97.96% for the grafts and 96.2% for the implants. The follow-up periods after rehabilitation ranged from 3 months to 13 years. Conclusions: Within the limitations of the data analyzed in this retrospective study, maxillary sinus lift was a viable surgical technique that enabled implant placement with a predictable long-term success rate, regardless of the type of material used. The presence of membrane perforation did not interfere with the success rate obtained for grafts and implants.

Retrospective Multivariate Clinical Analysis of 2707 Dental Implants with Hydrophilic and Hydrophobic Surfaces: Survival Rates after Up to 5 Years.

The aim of this retrospective study was to evaluate the long-term predictability of treatment using implants with hydrophobic and hydrophilic surfaces, according to clinical parameters and survival rates. Records from all patients who received dental implants between January 2013 and December 2014 at ILAPEO College were fully evaluated by two graduate dentists. Records with incomplete or unclear data were excluded from the study. The variables evaluated were demographic data, design of implants and prosthetic components, type of loading, data related to the patients' general health, and survival of implants and prostheses. The final retrospective sample comprised 776 patients with 2707 implants, with up to 5 years of follow-up. Survival rates of implants and prostheses were 97.93% and 98.77%, respectively. Implants with hydrophobic (97.87%) and hydrophilic (98.34%) surfaces exhibited similar survival rates. Considering the different types of loading, there was no statistically significant difference between loading protocols regarding implant survival rates. Unsuitable healing capacity, uncooperative and not motivated patient, loss of prosthesis, and peri-implant bone loss were confirmed statistically to be factors that may contribute to implant loss, according to hazard ratio and odds ratio. The present study showed similar and high overall survival rates for implant with both types of surfaces, in the long term. The surface treatment, implant model and loading protocol had no significant influence on implant loss. Therefore, the evaluated implant systems were able to offer a high predictability for both hydrophobic and hydrophilic implants.

Avaliação histológica e tomográfica do enxerto xenógeno em bloco para o preenchimento do seio maxilar / Histological and tomographic evaluation of the xenograft block for filling the maxillary sinus

O objetivo desse estudo foi avaliar, por meio de exame tomográfico e histológico, o comportamento do enxerto de osso bovino desproteinizado em cirurgias de elevação de soalho de seio maxilar. A amostra foi constituída por 7 pacientes do gênero feminino que necessitavam de instalação de implantes osseointegrados para reabilitação do rebordo posterior edêntulo total ou parcial da maxila e apresentavam pneumatização do seio maxilar com necessidade de aumento vertical através de técnicas de enxertia. Os pacientes foram submetidos à cirurgia de elevação de soalho de seio maxilar, sendo que a cavidade sinusal foi preenchida com enxerto bovino desproteinizado em forma de bloco que foi mantido fixo dentro do seio maxilar por meio de um parafuso de fixação do enxerto. Após 6 meses do procedimento cirúrgico, foi executada uma avaliação tomográfica para verificação do aumento da disponibilidade de tecido ósseo e análise histométrica das biópsias para avaliação da composição do tecido reparado. Verificou-se que houve aumento da altura do rebordo alveolar. Antes do procedimento cirúrgico era de 4,10 ± 2,03 mm e no momento da instalação dos implantes era de 19,04 ± 2,45 mm. Em termos de composição do tecido enxertado, foi verificado que houve a presença de 15,66% de tecido ósseo, 28,83% de biomaterial e 55,49% de tecido mole. Dessa forma, concluiu-se que a utilização de blocos de osso bovino desproteinizado em cirurgias de elevação de seio maxilar foi eficiente no aumento da disponibilidade óssea, o que permitiu a instalação de implantes (AU).

The aim of this study was to evaluate, by means of tomographic and histological examination, the behavior of deproteinized bovine bone graft blocks in maxillary sinus floor elevation surgeries. The sample consisted of 7 female patients who requires the installation of osseointegrated implants for rehabilitation of the posterior or total edentulous maxilla, that presented pneumatization of the maxillary sinus with the need for vertical increase through grafting techniques. Patients underwent maxillary sinus floor elevation surgery and the sinus cavity was filled with a deproteinized bovine graft in the form of ablock that was kept fixed inside the maxillary sinus by means of a graft ixation screw. After 6 months of the surgical procedure, a tomographic evaluation was performed to evaluate the increase of the availability of bone tissue and histometric analysis of the biopsies to evaluate the composition of the repaired tissue. It was verified that there was an increase in the height of the alveolar ridge. Before the surgical procedure was 4.10 ± 2.03 mm and at the moment of the installation of the implants was 19.04 ± 2.45 mm. In terms of the composition of the grafted tissue, it was verified that 15.66% of bone tissue was present, 28.83% of biomaterial, and 55.49% of soft tissue. Thus, it can be concluded that the use of deproteinized bovine bone blocks in maxillary sinus surgeries was efficient in increasing the bone availability that allowed the implantation of implants (AU).

Manejo de complicações protéticas de implantes zigomáticos ­ relato de caso com 1 ano de acompanhamento / Management of prosthetic complications of zygomatic implants - 1-year followup case report

A ancoragem de implantes em osso zigomático tem sido reconhecida como uma abordagem terapêutica menos invasiva quando comparada às grandes reconstruções para a reabilitação de maxilas severamente atróficas. Apesar de alcançar sucesso clínico elevado do ponto de vista cirúrgico e protético, melhorando a qualidade de vida e satisfação dos pacientes, problemas relacionados ao conforto da prótese são algumas vezes relacionados. Este caso clínico apresenta a resolução de 2 problemas: i) implantes zigomáticos do tipo cone morse em nível gengival, o que deixava a região côncava dos intermediários exposta ao meio oral e ii) hipersensibilidade na região de fossa nasal pela presença de implantes na região. A sensibilidade e trauma na língua, em decorrência dos implantes posteriores, foram solucionados pela personalização de um componente protético, enquanto a sensação de pressão na região anterior da maxila foi eliminada após a remoção de 2 implantes convencionais sem prejuízo à biomecânica da prótese implantossuportada (AU).

The anchorage of implants in the zygomatic bone has been recognized as a less invasive approach when compared to large reconstructions of severely atrophic maxilla. Although high rates of surgical and prosthetic success have been reached improving the patient life quality and satisfaction, problems in terms of prosthesis comfort are sometimes reported. This case report presents the resolution of 2 problems: i) morse taper zygomatic implants at the gingival level, resulting in the exposure of the concave area of the abutments and ii) hypersensitivity at the nasal cavity region, due to implants nearby this site. Sensitivity and tongue trauma, as a result of posterior implants, were solved by prosthetic component customization , while the pressure in the maxilla anterior area was eliminated after removing 2 conventional implants with no damage to the biomechanics of the implant supported prosthesis (AU).

Occlusal concepts application in resolving implant prosthetic failure: case report.

The prosthetic management of a poor implant treatment is presented in this case report. The recommended occlusion concepts for implant-supported prostheses were applied for the resolution of the case. The rehabilitation of the posterior segments provided a mutually protected occlusion with adequate distribution of the axial and lateral bite forces with stable posterior occlusion. The clinical exam indicated the need for modification in the vertical dimension of occlusion. Sufficient interocclusal rest space was present to test the alteration in the vertical dimension. The aim was to achieve an occlusion scheme that followed four specific criteria: (1) centric contacts and centric relation of the jaw-to-jaw position; (2) anterior guidance only; (3) shallow anterior angle of tooth contact; and (4) vertical dimension of occlusion with acceptable tooth form and guidance. The success of an oral rehabilitation relies in following the aforementioned criteria, appropriate interaction between the dental laboratory technician and the clinician, careful elaboration of the provisional rehabilitation with all the desired details to be reproduced in the final prosthetic restoration and sufficient follow-up time of the provisional prostheses before placing the final restoration.

Assessment of preload in carbon coated prosthetic screws

Introduction : The mechanical aspects of tightening screws over implants are important to ensure a successful prosthetic rehabilitation. Screw loosening is a common problem that can be avoided with passive adaptation of the components and an increased tensile force developed in the screw, a preload. Objective: This in vitro study evaluated the effect on preload of a carbon lubricant deposited on the surface of titanium alloy prosthetic screws: conventional Ti6Al4V and surface enhanced. Material and methods: Conventional titanium alloy prosthetic (n = 7) and carbon coating surface enhanced screws (n = 7) were compared. Each prosthetic screw supporting a metallic UCLA over an implant was tightened with the manufacturer’s recommended torque of 32 N.cm. The removal torque values, recorded for ten consecutive cycles of tightening and removal, were used to estimate the preload. Implant blocks were then sectioned and the interfaces were observed by light microscopy.Results: The lowest removal torque, and consequently the highest preload values, was achieved for the lubricated group in most cycles. The contacts between threads were located at the coronal aspect of all observed screw mating threads.Conclusion: Data indicate that the lower coefficient of friction of a carbon lubricant can generate higher preload. The machining precision observed produced the adaptation and regular contact interfaces.