Comparative analysis of biomechanical response between zygomatic implant and Facco technique through the three-dimensional finite element method.

Background: The placement of zygomatic implants is an alternative used for rehabilitation of edentulous patients with atrophic maxilla. However, the complexity of the various techniques suggested in the literature requires high skill from surgeons. Aim: The objective of this research was to compare the biomechanical performance of traditional technique of zygomatic implant placement in relation to a new proposal, the Facco technique, through finite element analysis. Material and Methods: A three-dimensional geometric model of the maxilla was input into computer-aided design software (Rhinoceros version 4.0 SR8). STL file of the geometric models of implants and components supplied by the company Implacil De Bortoli was converted to volumetric solids through reverse engineering by RhinoResurf software (Rhinoceros version 4.0 SR8). Three groups were modeled: traditional technique, Facco technique without frictional contact and Facco technique with frictional contact, following the recommended position in each technique for implant placement. All models received a maxillary bar. Groups were exported to the computer-aided engineering software ANYSYS 19.2, in step format. Mechanical static structural analysis was requested with occlusal load of 120N. All elements were considered isotropic, homogeneous, and linearly elastic. Contacts were considered ideal and system fixation was considered at the bone tissue base. Results: There is similarity between the techniques. Microdeformation values capable of generating undesirable bone resorption were not observed in both techniques. Highest values in the posterior region of Facco technique were computed at the angle of part B close to the posterior implant. Conclusions: Biomechanical behaviors of the two evaluated zygomatic implant techniques are similar. Prosthetic abutment (pilar Z) modifies the distribution of stresses over the zygomatic implant body. Highest stress peak was found in the pilar Z, but it is within acceptable physiological limits. Key words:Atrophic maxilla, zygomatic implants, surgical techniques, pilar Z, dental implants.

A Modified Technique for Induced Gingival Growth Around Compromised Teeth Prior to Implant Placement: A Report of Two Cases.

Regenerative and reconstructive periodontal plastic surgery are important options for treating marginal tissue recession and can be indicated for root coverage or periodontal procedures prior to implant placement. Among the available procedures, periodontal flaps with subepithelial connective tissue graft (CTG) is the most common treatment option to achieve proper tissue manipulation. The present study proposes a modification of a previous technique for inducing spontaneous gingival growth around teeth that will be extracted prior to implant placement, through successive reduction of the buccal root surface. This successive reduction of root surfaces is performed with diamond burs, and such reductions create space for the gingival tissue to grow coronally by reducing root convexity and, consequently, stimulating the healing process with the formation of granulation tissue that will then differentiate into keratinized tissue. The presented technique is suggested to improve the esthetic outcomes for cases involving tooth extraction, implant placement in the extraction socket, and immediate loading with interim restoration and CTG.

Analysis of stress distribution in ceramic and titanium implants in alveolar sockets of the anterior region of the maxilla.

BACKGROUND: In the routine of dentistry, knowing the biomechanical properties of implant systems and their inherent stress distribution under force loading is an essential step to predict structural damage and biological responses. This study aimed to investigate stress distribution in zirconia and titanium implants and their biomechanical response in alveolar sockets of the anterior region of the maxilla through tridimensional finite element analysis. MATERIAL AND METHODS: From computed tomography scans of a reference patient, three models of the maxillary dental arch were designed with Rhinoceros 5.0 software (McNeel Europe™, Barcelona, Spain). In each model, a dental implant replaced the maxillary left central incisor. The implants consisted of M1) Zirconia Pure Ceramic Implant Monotype; M2) Zirconia Pure Ceramic ZLA; and M3) Titanium Bone Level - Roxolid SLA. Ceramic crowns were installed in all the implants. Implants and prostheses were loaded with 50N oblique and axial forces. Von-Mises and Mohr Coulomb criteria were used to assess stress distribution in the implant systems and perimplantar bone, respectively. RESULTS: Traction was detected in the cervical region of the palatal bone surface of all the models. Oppositely, compression was found in the cervical region of the vestibular bone surfaces. CONCLUSIONS: Zirconia Pure Ceramic Implant Monotype had the best response under oblique force loading. Ceramic implants may be an alternative to replace titanium implants in fresh alveolar sockets in the anterior region of the maxilla. Key words:Finite elements, implants, stress, ceramic, titanium.

Análise comparativa pelo método dos elementos finitos da distribuição de tensões em pilares de próteses fixas implantossuportadas por implantes distais retos e inclinados / Comparative finite element analysis of stress distribution on abutments of fixed dentures supported by vertical and tilted posterior implants

Introdução: o conceito all-on-four preconiza a inclinação dos implantes distais com o objetivo de reduzir o cantiléver distal. Objetivo: avaliar a biomecânica através da análise com elementos finitos tridimensionais, a inclinação dos implantes distais e a utilização de componentes protéticos angulados e retos no tratamento de mandíbulas edêntulas. Métodos: quatro modelos tridimensionais de mandíbula foram criados simulando tecido ósseo cortical e medular. Foram instalados nos modelos quatro implantes paralelos com componentes protéticos retos, dois implantes retos com os dois implantes distais inclinados em 17 ou 30° com componentes protéticos retos ou angulados. Todos os modelos foram carregados axialmente ou obliquamente bilateral, ou unilateralmente em toda a extensão da prótese. Resultados: o uso de implantes retos e os componentes angulados apresentaram maiores concentrações de tensões. A inclinação distal dos implantes favoreceu a distribuição de tensões. Conclusão: o conceito all-on-four com o uso de componentes protéticos retos favorece a biomecânica de reabilitações totais implantossuportadas.

Avaliação da qualidade de vida de portador de displasia ectodérmica reabilitado com implantes osseointegrados: acompanhamento clínico e radiográfico de 5 anos / Assessment of life quality of a patient with ectodermal dysplasia rehabilitated with osseointegrated implants: five years clinical and radiographic follow-up

A displasia ectodérmica é uma desordem genética associada a anormalidades dentárias que resultam em severos problemas funcionais, estéticos e de qualidade de vida. Pacientes com displasia ectodérmica comumente sofrem com a ausência total ou parcial dos dentes, que ocasiona uma alteração nos padrões normais de desenvolvimento dos maxilares. Para reabilitação desses pacientes, os implantes dentários têm sido cada vez mais utilizados devido à severidade da doença limitar outras opções de tratamento reabilitador. Esse artigo traz um relato de caso com avaliação pré e pós-operatória da qualidade de vida de uma paciente com 55 anos de idade afetada por displasia ectodérmica que exibiu oligodontia e atrofia severa dos maxilares. Ela foi tratada com implantes osseointegrados, seguindo a filosofia de função imediata, baseada na filosofia do sistema Novum® em mandíbula e com a técnica All-on-4® híbrida em maxila, sendo 3 implantes zigomáticos e 1 convencional, apresentando follow-up de 5 anos.

Ectodermal dysplasia is a genetic disorder associated with dental anomalies that severely affect function, aesthetics and quality of life. Patients with ectodermal dysplasia often have complete or partial anodontia, which affects normal jaw development. Dental implants have increasingly been used for the rehabilitation of these patients because their disease severity reduces treatment options. This report describes the pre- andpostoperative quality of life of a 55-year old woman with ectodermal dysplasia that presented with hypodontia and severe atrophy of the jaws. She was treated with dental implants for immediate functional loadingusing the Novum® protocol for the mandible and the All-on-4® hybrid technique in the maxilla, together with zygomatic implants and 3 conventional implants. The patient was followed up for 5 years.