Feasibility of iterative closest point algorithm for accuracy between virtual surgical planning and orthognathic surgery outcomes.

PURPOSE: To evaluate the feasibility of iterative closest point (ICP) algorithm for assessing the accuracy between virtual surgical planning (VSP) and outcomes in orthognathic surgery. MATERIALS AND METHODS: VSP and results of surface mesh (SM0 and SM1) from CBCT scans of 25 patients who had been undergone bi-maxillary orthognathic surgery were converted into STL-format files and then imported to Geomagic software for semi-automatic alignment. ICP algorithm was used to calculate mean deviations (MD) and root mean square (3D error) at different calibrations of ±2 mm (T1), ±5 mm (T2) and ±10 mm (T3), with workflow being performed by two evaluators. Colour maps were generated to assess the 3D congruence qualitatively. Linear regression analysis was used to estimate whether SM0 or SM1 could condition the ICP and t-tests were used to assess whether MD and 3D error values were ≤-2 mm and ≥2 mm. Descriptive statistics was used to assess the method's feasibility by comparing T2 to T1 and T3. RESULTS: High intra- and inter-rater correlations supported the workflow reproducibility with the software. SM0 conditioned the ICP algorithm regarding both evaluators, and t-tests demonstrated that MD and 3D error were >-2 mm and <2 mm. MD and 3D error at T3 were 30% higher than those at T1. CONCLUSIONS: ICP algorithm provided a reproducible method, but its feasibility was limited due to underestimation or overestimation of the results as they affect the validity of the actual deviations.

Accuracy between virtual surgical planning and actual outcomes in orthognathic surgery by iterative closest point algorithm and color maps: A retrospective cohort study

Background: To evaluate the accuracy between actual outcomes and virtual surgical planning (VSP) in orthognathic surgery regarding the use of three-dimensional (3D) surface models for registration using iterative closest point (ICP) algorithm and generated color maps. Material and Methods: Construction of planning and postoperative 3D models in STL files format (M0 and M1, respectively) from CBCT of 25 subjects who had been submitted to bimaxillary orthognathic surgery was performed. M0 and M1 were sent to Geomagic software in semi-automatic alignment surface mesh order of M0 and M1 for registration using ICP algorithm to calculate mean deviation (MD, MD+, MD-, SD) and root mean square (RMS - 3D Error). Color maps were generated to assess qualitative congruence between M0 and M1. From deviation analysis, 3D Error was defined as accuracy measurement. To assess the reproducibility, the workflow was performed by two evaluators multiple times. t-tests were used to assess whether all means of MD, MD+, MD-, SD and 3D Error values would be ≤ - 2 mm and ≥ 2 mm. Results: High intra and inter evaluators correlation were found, supporting the reproducibility of the workflow. t-tests proved that all MDs and 3D Error values were > - 2 mm and < 2 mm. Conclusions: 3D error mean was within the standards of clinical success lower than 2 mm. ICP algorithm provided a reproducible method of alignment between 3D models and generated color maps to evaluate 3D congruence but did not answer all methodological parameters regarding the assessment of accuracy in orthognathic surgery

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Alteration of Occlusal Plane in Orthognathic Surgery: Clinical Features to Help Treatment Planning on Class III Patients.

Dentofacial deformities (DFD) presenting mainly as Class III malocclusions that require orthognathic surgery as a part of definitive treatment. Class III patients can have obvious signs such as increasing the chin projection and chin throat length, nasolabial folds, reverse overjet, and lack of upper lip support. However, Class III patients can present different facial patterns depending on the angulation of occlusal plane (OP), and only bite correction does not always lead to the improvement of the facial esthetic. We described two Class III patients with different clinical features and inclination of OP and had undergone different treatment planning based on 6 clinical features: (I) facial type; (II) upper incisor display at rest; (III) dental and gingival display on smile; (IV) soft tissue support; (V) chin projection; and (VI) lower lip projection. These patients were submitted to orthognathic surgery with different treatment plannings: a clockwise rotation and counterclockwise rotation of OP according to their facial features. The clinical features and OP inclination helped to define treatment planning by clockwise and counterclockwise rotations of the maxillomandibular complex, and two patients undergone to bimaxillary orthognathic surgery showed harmonic outcomes and stables after 2 years of follow-up.

Influência da cirurgia ortognática na harmonia facial: série de casos / Influence of orthognathic surgery on facial harmony: case series

A cirurgia ortognática é uma opção terapêutica viável no tratamento daqueles pacientes que apresentam deformidades dento-esqueléticas. De acordo com a literatura, esse procedimento cirúrgico possibilita aos pacientes resultados funcionais e estéticos, proporcionando mudanças significativas na vida destes. Sendo assim, este trabalho teve por objetivo relatar uma série de casos de pacientes submetidos à cirurgia ortognática, cujos resultados pós-operatórios demonstram uma importante melhora na harmonia facial destes, o que vem a confirmar que esse procedimento é um importante instrumento de mudança na vida dos pacientes, possibilitando uma convivência normal destes em sociedade... (AU)

The orthognathic surgery is a viable therapeutic option in the treatment of those patients who have dental-skeletal deformities. According to the literature, this surgical procedure allows the functional and aesthetic results patients, providing significant changes in their lives. Thus, this study aimed to report a case series of patients undergoing orthognathic surgery whose postoperative results show a significant improvement in facial harmony of the same, which confirms that this procedure is an important tool change in the lives of patients, allowing a normal coexistence of these patients in society... (AU)

Desafios na reconstrução mandibular devido a lesões extensas ou traumatismos / Challenges in mandibular reconstruction due to extensive injuries or trauma

A perda de grande parte do osso mandibular, seja devido à necessidade de ressecção óssea ou por outros fatores como a ocorrência de traumatismos, afeta diretamente a vida dos pacientes. Mesmo com a melhoria contínua dos materiais, surgimento de novas tecnologias e técnicas cirúrgicas, o tratamento dessas grandes lesões e perdas ósseas permanece como grande desafio ao cirurgião. Nesse sentido, o objetivo do presente trabalho foi relatar dois casos clínicos de pacientes, sendo um de fibroma ossificante central de mandíbula que foi submetido à ressecção mandibular e tratado através da colocação de uma placa de reconstrução do sistema 2.4 mm. O segundo caso envolveu perda de substancia devido a paciente ter sido vitima de ferimento por arma de fogo (FAF), evoluindo com fratura do sistema de fixação colocado na primeira cirurgia. Em segundo momento cirúrgico a paciente foi submetida à reconstrução óssea do defeito, associado à colocação de nova fixação. Deste modo, podemos afirmar que os procedimentos reconstrutivos são importantes instrumentos para tratamento dos pacientes.

The loss of much of the mandibular bone, is due to the need for bone resection or by other factors such as the occurrence of injuries, directly affects the lives of patients. Even with the continuous improvement of materials, development of new technologies and surgical techniques, treatment of these large lesions and bone loss is still a major challenge for the surgeon. In this sense, the objective of this study was to report two clinical cases of patients, a central ossifying fibroma of the mandible who underwent mandibular resection and treated by placement of a reconstruction plate system 2.4mm. The second case involved loss of substance because the patient has been the victim of injury by firearms (FAF), evolving with fracture fixation system placed in the first surgery. In the second surgical time the patient underwent bone reconstruction of the defect associated with the placement of new fixation. Thus, we can say that reconstructive procedures are important tools for treatment of patients.

Descompressão cirúrgica no tratamento de lesões císticas da cavidade oral / Surgical decompression in the treatment of cystic lesions of the oral cavity

Os cistos são lesões formadas por uma cavidade revestida de tecido epitelial, as quais contêm, em seu interior, material líquido ou semisólido, podendo ser classificados em cistos odontogênicos e não odontogênicos. Apesar de existirem diversas modalidades de tratamentos descritas na literatura para tratamentos dos cistos da cavidade oral, até o presente momento, não se observa um consenso em relação à qual técnica que oferece os melhores resultados. Sendo assim, procurou-se relatar um caso clínico com a utilização da técnica de descompressão, procurando evidenciar suas indicações, vantagens, desvantagens e demais peculiaridades... (AU)

Cysts are lesions formed by a cavity lined with epithelial tissue, which contains in its interior material liquid or semisolid, and may be classified into odontogenic cysts and non-odontogenic. Although there are several treatment modalities described in the literature for treatment of cysts of the oral cavity, to date not seen a consensus as to which technique offers the best results. Therefore, we sought to a case report using the technique of decompression, seeking to highlight their indications, advantages, disadvantages and other peculiarities... (AU)

Malignant lymphoma of the oral cavity and the maxillofacial region: Overall survival prognostic factors

Objective: To identify the overall survival and prognostic factors of malignant lymphoma of the oral cavity and the maxillofacial region. Study Design: Clinical records data were obtained in order to determine overall survival at 2 and 5 years, the individual survival percentage of each possible prognostic factor with the actuarial technique, and the survival regarding the possible prognostic factors with the actuarial technique and the Log-rank and Cox's regression tests. Results: Of 151 subjects, an overall survival was 60% at 2 years, and 45% at 5 years. The multivariate analysis demonstrated statistically significant differences for clinical stage (p=0.002), extranodal involvement (p=0.030), presence of human immunodeficiency virus (p=0.032), and presence of Epstein-Barr virus (p=0.010). Conclusion: The advanced clinical stage and the larger number of involved extranodular sites are related to a lower overall survival, as well as, the presence of previous infections such as the human immunodeficiency and the Epstein-Barr virus (AU)

Malignant lymphoma of the oral cavity and the maxillofacial region: overall survival prognostic factors.

OBJECTIVE: To identify the overall survival and prognostic factors of malignant lymphoma of the oral cavity and the maxillofacial region. STUDY DESIGN: Clinical records data were obtained in order to determine overall survival at 2 and 5 years, the individual survival percentage of each possible prognostic factor with the actuarial technique, and the survival regarding the possible prognostic factors with the actuarial technique and the Log-rank and Cox's regression tests. RESULTS: Of 151 subjects, an overall survival was 60% at 2 years, and 45% at 5 years. The multivariate analysis demonstrated statistically significant differences for clinical stage (p=0.002), extranodal involvement (p=0.030), presence of human immunodeficiency virus (p=0.032), and presence of Epstein-Barr virus (p=0.010). CONCLUSION: The advanced clinical stage and the larger number of involved extranodular sites are related to a lower overall survival, as well as, the presence of previous infections such as the human immunodeficiency and the Epstein-Barr virus.

Influencia del diámetro y longitud de implantes en la pérdida tardía de implantes dentales / Influence of diameter and length of implant on late dental implant failure

El objetivo de esta investigación fue describir la influencia del diámetro y largo de los implantes en la pérdida tardía del implante. Se diseñó un estudio retrospectivo para estudiar 375 pacientes que habían sido sometidos a rehabilitación oral sobre implantes durante un periodo de 11 años; se incluyeron en el estudio todos aquellos documentos debidamente completados y con estudios radiográficos preoperatorios, posterior a la instalación del implante y posterior a la instalación de la prótesis. Los implantes fueron clasificados de acuerdo al diámetro como estrecho, regular y ancho y de acuerdo al largo como corto, medio y largo; el análisis de datos fue realizado con la prueba Chi Cuadrado con valor de p<0,05. Del total de 939 implantes y se identificó la pérdida de 55 implantes posterior a la etapa protésica (5,8 por ciento). En base a la pérdida, no se logró establecer ninguna relación estadísticamente significativa con el diámetro del dispositivo (p=0,475) y tampoco con el largo del implante (p=0,064). Podemos concluir que el largo y el diámetro de implantes dentales no influyen en la pérdida tardía del mismo.

The aim of this research was to describe the influence of diameter and length of dental implant related to late implant faliure. In a retrospective study was evaluated 375 patients in a 11 year period; were inclued the complet medical record with image study in the preoperative period, posteriorly to implant installation and to prosthesis installation. The implant was classified according to diameter in narrow, regular and wide, and according to length as short, regular and long. The statistical analysis was realized with Chi-Squaare test with p value <0.05. We studied 939 implants and observed 55 implant failure posteriorly to prosthesis phases (5.8 percent). No statistical relation with diameter (p=0.475) or lenght (p=0.064) was observed. We conclude that the length and diameter of dental implant is not an influence for late failure of the implant.

Early osseous tissue formation associated to submerged and non-submerged dental implants: a histomorphometric animal study / Formación temprana de tejido óseo asociado a implantes dentales sumergidos y no sumergidos. Un estudio histomorfométrico animal

The purpose of this research was to compare the bone formation around submerged and non-submerged implants installed in a mandible of dog. Seven beagle dogs were used in this protocol; initially, was performed extraction of posterior teeth of mandible and after 3 month healing were installed two dental implants with surface treatment (subtraction of titanium via acidification) in each hemimandible. A transmucosal healing screw of 7 mm without oclusal contact was installed at the anterior implant as a model of non-submerged implant; in the posterior implant were installed a cover screw, using the submerged technique. After six weeks of healing, histomorphometric analysis of osseous tissue between the threads was performed. Was analyzed the implant unit as well as the cervical, meddle and apical region of implant. Student t test with 5 percent significance was used. The non-submerged implant model showed more bone formation than submerged implant without statistically significance (p=0.106); for regional analyses, cervical area shows more osseous formation than middle and apical areas. The regional analyses did not present statistical difference between areas for comparative analysis of submerged and non-submerged implant model. Non-submerged implant model it's not an obstacle for osseous formation.

El objetivo de esta investigación fue comparar la formación ósea alrededor de implantes dentales sumergidos y no sumergidos instalados en mandíbula de perro. Siete perros Beagle fueron utilizados en este protocolo; inicialmente fueron realizadas las exodoncias de dientes posteriores de mandíbula y luego de 3 meses de recuperación fueron instalados dos implantes dentales con tratamiento de superficie en cada hemimandíbula (substracción de titanio vía acidificación). En el implante anterior fue instalado también un conector transmucoso de 7 mm sin contacto oclusal y en el implante posterior fue instalado el tornillo de cierre. Luego de 6 semanas de recuperación, se realizó un análisis histomorfométrico del tejido óseo presente entre las roscas. Se analizó el implante como unidad así como también sus sectores cervical, medio y apical. Se utilizó la prueba estadística t de student con 5 por ciento de significancia estadística. El implante no sumergido presentó mayor formación ósea sin diferencias estadísticamente significativa (p=0.106); en los análisis regionales, el área cervical presentó mayor formación ósea que las áreas medianas y apicales. El análisis regional no presentó diferencias estadísticamente significativas entre ambos tipos de implante. El modelo de implante no sumergido no es un obstáculo para la formación ósea.

Retrospective four year analysis in 199 bone grafts of the alveolar ridge / Análise retrospectiva de quatro anos em 199 enxertos autógenos do rebordo alveolar

Objective: To evaluate the factors that lead to complications in autogenous bone grafting. Methods: Review of clinical records of the patients that were candidates for rehabilitation, between May 2004 and December 2008. With regard to the donor area, of the 199 reconstructions, 175 were autogenous bone graft procedures and 210 donor areas were acted upon.Results: A total of 48 procedures (24.12%) were grafts using particulate bone while sinus lift grafts were performed on 28 patients (14.07%).Osteogenesis distraction and inferior alveolar nerve lateralization were performed in five (2.51%) and three (1.51%) procedures respectively.Eleven autogenous bone grafts were lost, of which 90.9% were onlay block. Conclusion: The use of autogenous bone grafting in atrophic alveolar ridge reconstruction is a highly successful treatment, and the sinus lift procedure is the most predictable form of treatment.

Objetivo: Avaliar os fatores que levam às complicações em enxertia óssea autógena. Métodos: A amostra foi composta pela revisão de prontuários clínicos de pacientes candidatos à reabilitação no período entre maio de 2004 e dezembro de 2008. Em relação à área doadora, das 199 reconstruções, 175 foram procedimentos de enxerto de osso autógeno, sendo abordadas 210 áreas doadoras. Resultados: Os enxertos com osso particulado totalizaram 48 procedimentos (24,12%). O levantamento de seio maxilar foi realizado em 28 pacientes (14,07%). Já a distração osteogênica e lateralização do nervo alveolar inferior foi realizada em cinco (2,51%) e três (1,51%) procedimentos respectivamente. Foi registrada a falha de 11 enxertos com osso autógeno. Dos enxertos perdidos, 90,9% deles foram os de bloco tipo onlay. Conclusão: A utilização de enxertos ósseos autógenos nas reconstruções de rebordos alveolares que apresentam atrofia é um tratamento com alto índice de sucesso, destacando-se a cirurgia de levantamento de soalho de seio maxilar como a modalidade mais previsível de reconstrução óssea.

Otimização em reconstrução total de maxila através da modificação estrutural do enxerto e diminuição do intervalo cirúrgico / Optimizing total maxillary reconstruction through structural graft modification and surgical timing decrease: a case report

Quando o tema refere-se a enxertos e reconstruções ósseas em grandes proporções, sabe-se que o osso autógeno ainda é o biomaterial de escolha do profissional, sendo a região de crista ilíaca a mais utilizada como área doadora. Porém, dentre as desvantagens da sua utilização destaca-se o alto potencial de reabsorção deste enxerto, que em alguns casos pode ser observado no momento da colocação do implante, inviabilizando a sua inserção. O presente trabalho teve como objetivo apresentar um relato de caso clínico de reconstrução óssea de maxila severamente reabsorvida com a utilização de enxerto ósseo autógeno de crista ilíaca, apresentando considerações clínicas que otimizaram esta modalidade de tratamento. A prévia compressão da porção medular do enxerto em bloco, o preenchimento com osso particulado autógeno dos espaços entre os blocos inseridos, bem como a redução do tempo entre a enxertia e a inserção dos implantes foram determinantes na ausência de reabsorção do osso autógeno observada no momento do segundo tempo cirúrgico, adotando-os como protocolo cirúrgico para este tipo de reabilitação.

This study aimed to present a case report on the reconstruction of a severely resorbed maxilla using the autogenous iliac crest bone graft, highlighting clinical considerations to optimize this treatment modality. Previous compression of the marrow portion added to the filling with particulate autogenous bone between block grafts, as well as less time between grafting and implant placement were instrumental in the absence of bone resorption at the second-stage moment, adopting this protocol for this procedure.

Reposicionamento cirúrgico de implante osseointegrado através de osteotomia segmentar: relato de caso / Surgical repositioning of osseointegrated dental implant through segmental osteotomy: Case report

Para se obter previsibilidade no tratamento com implantes osseointegrados, sabe-se que o planejamento reverso é considerado um requisito fundamental. Porém, determinados fatores, que vão desde a habilidade do profissional a intercorrências transoperatórias, podem resultar no mal posicionamento do implante, que muitas vezes é observado no momento da reabilitação protética. Para a resolução desse problema, a técnica da osteotomia segmentar com enxerto interposicional pode ser realizada, com o objetivo de possibilitar a posterior reabilitação protética desses implantes dentro dos padrões funcionais e estéticos satisfatórios. O objetivo do presente estudo é demonstrar a aplicabilidade dessa técnica por meio do relato de um caso de implante, na região do elemento 11, que foi inserido insatisfatoriamente no sentido vertical, acarretando em insatisfação estética por parte do paciente. Ao término do tratamento, observou-se que a resolução estética do caso foi possível sem a necessidade de remoção do implante e, consequentemente, cirurgias adicionais. Assim, conclui-se que essa técnica está indicada para o reposicionamento de implantes osseointegrados.

Seeking for predictability in osseointegrated implant treatment, the reverse planning is essential. However, factors such as the ability of the professional and surgical complications result in improper placement of dental implants that go unnoticed until the time of prosthetic rehabilitation. To resolve these complications, the segmental sandwich osteotomy combined with an interpositional autograft can be performed to allow for the placement of implants within the satisfactory functional and esthetic results. The objective of this study is to report the case of a vertically misplaced implant which caused esthetic complaints of the patient. Esthetic resolution of the case was observed at the end of treatment, without the need for implant removal and additional surgery, concluding that this technique is indicated for the repositioning of osseointegrated implants.

Acidentes durante a realização da osteotomia sagital do ramo mandibular: relato de caso / Accidents during the course of the sagittal split osteotomy of the mandibular ramus: Literature review and case report

A osteotomia sagital do ramo mandibular é um procedimento amplamente utilizado para a correção de deformidades dentofaciais, tanto para aquelas que necessitam de avanços ou recuos mandibulares. Diversos autores realizaram estudos e sugeriram modificações procurando aperfeiçoar esta técnica, sendo que na atualidade este pode ser considerado um procedimento corriqueiro, versátil e previsível. Mas, como toda técnica cirúrgica, ela não esta livre da ocorrência de acidentes e complicações. Sendo assim, o objetivo do presente trabalho é relatar o caso clínico de uma paciente submetida à realização de OSRM para tratamento de retrognatismo mandibular, onde durante o procedimento cirúrgico houve uma fratura indesejada no segmento proximal, bem como a descrever forma de tratamento realizada.

The sagittal split osteotomy of the mandibular ramus is a widely used procedure for the correction of dentofacial deformities, both for those who require mandibular advances or retreats. Several authors have conducted studies and suggested changes trying to perfect this technique, and at present this procedure can be considered predictable and versatile. But, like any surgical technique, it is not free of accidents and complications. Therefore, the objective of this study is to report the case of a patient submitted to a sagittal split osteotomy of the mandibular ramus for treatment of mandibular retrognathia, where during the surgical procedure was an unwanted fracture in the proximal segment, as well as to describe a form of treatment performed.

Mineralized tissue formation associated with 2 different dental implant designs: histomorphometric analyses performed in dogs.

The clinical success of dental implants might be associated with such factors as installation technique, implant shape, size, material, and screw threads. Therefore, the aim of this study is to analyze mineralized tissue formation on the screw threads of conical and cylindrical dental implants. This study includes 7 beagle dogs that had the lower premolars extracted. Three months after bone and soft tissue repair, 2 different designs of dental implants (1 conical and 1 cylindrical) were installed in each hemimandible using a nonsubmerged technique. Both implants when installed had different shape and thread, as revealed by scanning electron microscopy. Six weeks after implant installation, animals were killed and submitted to histomorphometric analysis. Cervical, middle, and apical areas were analyzed. Statistical analysis was carried out using Student t test at a significance level of P < .05. Statistically significant differences were not found between the conical and cylindrical implants. The conical implants presented fewer threads, a smaller area, and more bone formation when compared with the cylindrical ones, without significant differences (P  =  .1226). The highest values concerning bone formation were observed for the cervical area (P  =  .4005), and the lowest for the apical area (P  =  .1899); however, no statistically significant difference was observed. In conclusion, no statistically significant difference was observed in thread bone formation between the cylindrical and conical implant designs when placed using the nonsubmerged technique.

Osteotomia segmentar com enxerto ósseo interposicional em Implantodontia / Segmental Osteotomy with interpositional bone allograft in Implantology: clinical considerations

A insuficiência óssea, tanto em altura como em espessura, é apresentada com uma dificuldade para reabilitações com implantes dentários osseointegráveis. Esta condição que normalmente ocorre após a perda dentária, por problemas periodontais, cáries, traumas e outros, proporciona uma reabsorção local que impossibilita a reabilitação com implantes endósseos. Têm sido relatadas inúmeras técnicas para aumento do rebordo alveolar. O uso de materiais autógeno, alógeno e aloplástico e regeneração óssea guiada tem sido frequentemente descrito. Apesar da necessidade de sítio doador e mobilidade cirúrgica, o enxerto ósseo autógeno continua sendo o mais previsível e com maiores índices de sucessos. Entre os procedimentos de reconstrução temos a técnica de osteotomia segmentar com enxerto ósseo interposicional, que tem se tornado uma opção viável de tratamento para a obtenção de altura óssea adequada. Ela constitui um procedimento seguro, com índice alto de sucesso, onde as deficiências verticais moderadas podem ser corrigidas. No presente trabalho, relatou-se um caso clínico mostrando a técnica cirúrgica baseada na utilização da osteotomia segmentar do rebordo alveolar da região posterior de mandíbula, utilizando enxerto ósseo interposicional removido do ramo ascendente da mandíbula.

Horizontal or vertical alveolar ridge deficiencies are a problem for placing dental implants. These conditions usually are seen after tooth extraction, periodontitis, or dental traumas, providing compromised sites for implant placement. There are several treatment options for alveolar ridge augmentation. The use of autologous, allogenic, or aloplastic materials have been described. Despite the need of a donor site, autologous bone grafts remain the most predictable material available. One of the techniques for bone reconstruction is the segmental osteotomy with interposition bone graft, being this technique safe and predicable to treat vertical bone defects. This paper reports a case of segmental osteotomy with interpositional autogenous bone graft from mandibular ramus to vertically reconstruct the posterior mandibular body.

Avaliação da biocompatibilidade de um sistema para fixação interna baseado em polímero reabsorvível: estudo histológico em coelhos / Biocompatibility evaluation of a system for internal fixation based on a resorbable polymer: a histological study in rabbits

Algumas características indesejáveis dos materiais de fixação metálicos instigaram pesquisadores no desenvolvimento de um sistema para fixação interna reabsorvível, necessitando, dessa forma, de estudos para avaliar o seu comportamento principalmente em relação à biocompatibilidade. Sendo assim, o objetivo do presente estudo foi o de avaliar histologicamente, de forma comparativa, a reação do tecido ósseo local ao emprego de um sistema de fixação interna reabsorvível, baseado no polímero poli (L-co-D,L ácido lático) 70:30, utilizando como controle um sistema de fixação interna baseado em uma liga de titânio (Ti-6Al-4V/Grau V) de mesmas dimensões. Para isso, foram selecionados 15 coelhos adultos, albinos, da raça Nova Zelândia, fêmeas, com idade aproximada de 06 meses e peso variando entre 3,8 e 4,5 kg no momento do procedimento cirúrgico. Cada animal recebeu, ao mesmo tempo, o sistema reabsorvível e o metálico, sendo sacrificados aleatoriamente com 3, 8 e 16 semanas pós-operatórias. Como resultado histológico, observou-se que o sistema de fixação baseado em polímero apresentou um comportamento histológico bastante semelhante ao sistema metálico. Em nenhum período dos sacrifícios de ambos os grupos, notou-se a presença de reação tecidual exacerbada. Dessa forma, conclui-se que o sistema de fixação baseado no reabsorvível apresentou biocompatibilidade satisfatória com o leito receptor.

Some undesirable characteristics of metal fixation materials prompted researchers to develop a system for resorbable internal fixation, thus requiring studies to evaluate their behavior, particularly with regard to their biocompatibility. The aim of this study was to make a comparative histological evaluation of the reaction of bone tissue to a local internal fixation system based on resorbable poly (L-co-D, L-lactic acid) 70:30, using an internal fixation system with the same dimensions based on a titanium alloy (Ti-6Al-4V/Grau V) as a control. For this purpose we selected 15 female albino New Zealand rabbits, aged approximately 6 months and weighing between 3.8 and 4.5 kg at the time of surgery. Each animal received both the absorbable and metallic systems, with the animals being randomly sacrificed postoperatively at 3, 8 and 16 weeks. No exacerbated reaction of this tissue was observed at the time of sacrifice in either group. We thus conclude that the fixation system based on resorbable material displayed a satisfactory biocompatibility with the recipient bed.

Manipulación del plano oclusal en cirugía ortognática: consideraciones faciales / Manipulation of the oclusal plane in orthognathic surgery: facial considerations

El plano oclusal ha sido un elemento importante en cirugía ortognática durante los últimos 20 años. Las investigaciones iniciales demostraron que las características faciales están altamente asociadas a la posición mandibular; siendo así, la rotación del plano oclusal permite una reposición oclusal diferente de la inicial, además una relación facial tanto vertical como anteroposterior favorable en términos de estética y proporciones faciales. Las investigaciones realizadas para cuantificar y caracterizar este movimiento han sido limitadas, pero auspiciosas; se ha determinado que la rotación del plano oclusal es un movimiento estable y versátil, siendo útil en diferente tipos de pacientes. El objetivo de este estudio es identificar las principales características asociadas a la rotación del plano oclusal así como analizar las principales investigaciones al respecto.

Occlusal plane has been an important element in orthognatic surgery during these last 20 years. The primary investigations have shown that facial characteristics are highly associated to mandibular positioning. Thus, occlusal plane rotation allows an acclusal plan different from the initial one, even as vertical and anterior-posterior positioning more favorable en endings of aesthetic. Besides the studies carried through to measure y to characterize these movements are limited, they are favorable. They have demonstrated that occlusal plane rotation versatile y stable, being useful en different types of facial deformities. The meaning of this work are identify the more important characteristic about occlusal plane rotation as well analyze the most cited articles in the literature.

Complicações em fixações zigomáticas: revisão da literatura e análise retrospectiva de 16 casos / Complications in zygomatic fixtures: literature review and retrospective analysis of 16 cases

A reabilitação de maxilas atróficas permanece como grande desafio ao cirurgião, mesmo nos dias atuais. Nos últimos anos, as fixações zigomáticas têm sido apresentadas na literatura como uma opção viável para o tratamento daqueles pacientes que apresentam severa atrofia do rebordo alveolar maxilar com extensa pneumatização dos seios maxilares e que não desejam se submeter a procedimentos reconstrutivos. Sendo assim, o objetivo do presente estudo é realizar uma breve revisão da literatura e avaliar retrospectivamente as complicações encontradas em 16 casos de implantes zigomáticos, em um período mínimo de 24 meses de acompanhamento. Os resultados mostram que o percentual de complicações foi de 50% e que o índice de sucesso no tratamento foi de 76%. A dor foi o tipo de complicação mais comum (30%), seguida pela não osseointegração (25%) e pela infecção (20%). Em conclusão, podemos afirmar que complicações podem ocorrer em qualquer fase do tratamento e podem ocasionar a perda dos implantes zigomáticos instalados, devendo o cirurgião estar apto a intervir no momento necessário.

The rehabilitation of atrophied maxillary arches stands is a great challenge to surgeons. In the last years, the zygomatic fixations have been presented in literature as a practicable option to the treatment of patients with severe atrophy, large pneumatization of maxillary sinuses, and avoiding reconstructive procedures. In this case, the aim of this study is to perform a brief literature review and retrospectively evaluate the complications found in 16 cases of zygomatic implants, with a minimum period of 25- month follow-up. The results show that the percentage of complications was 50%, and the treatment success rate was 76%. Pain was the most common complication (30%), followed by the lack of integration (25%), and infection (20%). In this way, we can affirm that complications may occur in any treatment phase with loss of the zygomatic implant installed, obligating surgeons to interfere in certain occasions

Reconstrução alveolar com enxerto ósseo autógeno e malha de titânio: análise de 16 casos / Alveolar reconstruction with autogenous bone graft and titanium micromesh: analysis of 16 cases

O objetivo deste estudo foi avaliar um protocolo cirúrgico para a reconstrução de rebordos alveolares em altura e espessura na maxila empregando enxerto ósseo autógeno associado à malha de titânio. Foi selecionado um grupo de 16 pacientes que necessitavam de aumento do rebordo alveolar em altura de ao menos 4 mm com defeito em espessura associado. Durante uma primeira etapa cirúrgica foi retirado enxerto ósseo autógeno da região de ramo ou sínfise mandibular, que foi particulado e posicionado no leito receptor, recoberto por uma malha de titânio que foi fixada por meio de parafusos para osteossíntese em titânio. O ganho ósseo foi obtido em 14 pacientes possibilitando a instalação de implantes dentários, sendo classificado como sucesso clínico. A taxa de intercorrências pós-operatórias foi de 87,5%, sendo a exposição da malha de titânio o evento mais encontrado. A média de aumento vertical no momento da reabertura dos enxertos foi de 5,4 mm (variação de 3,5 mm a 13 mm). Os resultados preliminares sugerem que, empregando-se a presente técnica, rebordos alveolares residuais em pacientes parcialmente edêntulos podem ser reconstruídos com sucesso por meio de enxerto ósseo autógeno associado à malha de titânio.

The aim of this study is to evaluate a surgical protocol for vertical and transversal ridge augmentation in the maxilla using autogenous onlay bone graft associated with a titanium mesh. A group of 16 partially edentulous patients in need of vertical bone augmentation (at least 4mm) with transversal alveolar ridge defect associated, were treated before implant placement. On the first surgery, an autogenous bone graft was harvested from either the mandibular ramus or the mental symphysis and secured by means of titanium screws. Particulate bone was added and a titanium micro-mesh used to stabilize and protect the graft. Bone gain was reached in 14 patients classified as clinical success. The rate of post-operative complications was 87.5% (mesh exposure). Mean vertical bone augmentation obtained was 5.4 mm (range from 3.5 mm to 13 mm). The preliminary results suggest that, by using this technique, residual alveolar ridges in partially edentulous patients can be successfully reconstructed by means of autogenous bone graft and titanium micro-mesh.