Mechanical Evaluation of Different Stable Internal Fixation Techniques of Sagittal Osteotomy in Mandibular Advance / Evaluación Mecánica de Diferentes Técnicas de Fijación Interna Estable de Osteotomía Sagital en Avance Mandibular

The mandibular advancements performed in orthognathic surgeries can be stabilized with several techniques when using stable internal fixation. This study aims to comparatively evaluate, in vitro, the mechanical strength in a polyurethane mandibular model for four fixation techniques for sagittal split ramus osteotomy mandibular. 60 samples were divided into 4 groups, with 15 units for each group: group A, group B, group C and group D. Advances of 5 mm were made for each subgroup and fixed with 2.0 mm system plates and monocortical screws in the replicas of human hemimandibles in polyurethane resin. The samples were submitted to mechanical tests of linear loading, being evaluated the peak load and peak deformation. Technique B presented higher peak load (Kgf) and techniques A and B presented higher peak strain (p<0.05). Technique D presented lower peak load and lower peak strain (p<0.05). It is concluded that the study based on the development of new techniques for fixation for sagittal osteotomy of the mandibular ramus is of great importance for the advancement of orthognathic surgery, provided by the technical innovation of more favorable plate models.

Los avances mandibulares realizados en cirugías ortognáticas pueden estabilizarse con varias técnicas cuando se utiliza fijación interna estable. Este estudio tuvo como objetivo evaluar comparativamente, in vitro, la resistencia mecánica en un modelo mandibular de poliuretano para cuatro técnicas de fijación para la osteotomía sagital de la rama mandibular. Se dividieron 60 muestras en 4 grupos, con 15 unidades para cada grupo: grupo A, grupo B, grupo C y grupo D. Se realizaron avances de 5 mm para cada subgrupo y se fijaron con placas de sistema de 2,0 mm y tornillos monocorticales en las réplicas de hemimandíbulas humanas en resina de poliuretano. Las muestras fueron sometidas a pruebas mecánicas de carga lineal, siendo evaluadas la carga máxima y la deformación máxima. La técnica B presentó mayor pico de carga (Kgf) y las técnicas A y B presentaron mayor pico de deformación (p<0,05). La técnica D presentó menor carga máxima y menor tensión máxima (p<0,05). Se concluye que el estudio basado en el desarrollo de nuevas técnicas de fijación para la osteotomía sagital de la rama mandibular es de gran importancia para el avance de la cirugía ortognática, proporcionada por la innovación técnica de modelos de placas más favorables.

Retraction: Bacterial adhesion and colonization differences between zirconia and titanium implant abutments: an in vivo human study.

[This retracts the article on p. 217 in vol. 42, PMID: 23346465.].

Resistance of four fixation techniques used to treat subcondylar fractures.

OBJECTIVE: This study aimed to evaluate the resistance of four fixation techniques used to treat subcondylar fractures. The following techniques were evaluated: fixation with one 4-hole single straight plate; fixation with one 2-mm 4-hole system plate and one 1.5-mm 3-hole system plate; fixation with two 2-mm plates with a 3-hole anterior plate; and fixation with two 2-mm plates with four holes each. STUDY DESIGN: Each fixation technique was subjected to a resistance test. The load values were measured when displacement of 1, 2, and 5 mm was reached. Load values were compared for statistically significant differences using analysis of variance (ANOVA; p < 0.5) and Tukey's test. RESULTS: Statistically significant differences were observed, when the load was applied to the first molar on the side of the fracture. The group treated with a 4-hole, 2-mm, one plate system showed resistance to lower load values than the groups treated with two plates in any combination. CONCLUSIONS: When the fracture was fixed using two plates, regardless of the kind of plates used, no statistically significant difference between the groups was observed. However, two plate systems showed better resistance than one plate systems.

Photoelastic evaluation of two different sagittal split ramus osteotomies in advancement surgery.

The aim of this study was to establish the influence of the design of the sagittal split ramus osteotomy (SSRO) on stress distribution on the osteosynthesis in a photoelastic resin model. Two polyurethane hemimandibles were used to perform the osteotomies, tilted in the lateral sector of the first/second molar (group I) and the other descending downwards and laterally from the first molar (group II), with no higher angle. Six replicas of each were made in photoelastic resin and stabilized with a plate and 5 mm monocortical screws in a standardized way. Stabilization was done in the SSRO without advancement, with 3 mm advancement and with 7 mm advancement. Compressive loads were applied at the level of the lower first molar in an Instron machine (model 4411) with a speed of 1 mm/min until reaching 3 mm of displacement, at which point the data was recorded with a camera to identify the stress distribution bands. The results showed stress distribution in different places: for group I it was observed mainly in the screws of the proximal segment, being more intense closer to the osteotomy; in group II I it was observed mainly in the screws of the proximal segment furthest from the osteotomy, also being distributed towards the upper area of the plate. It may be concluded that under standard osteosynthesis conditions, modifications to the SSRO produce changes in the location and distribution of stress.

Influence of the design in sagittal split ramus osteotomy on the mechanical behavior.

The aim of this study was to determine the influence of the design of the sagittal split ramus osteotomy (SSRO) on the mechanical resistance to vertical forces. An in vitro study was designed for 30 test specimens. Two osteotomy models were made on two polyurethane hemimandibles, where group I presented a SSRO with an angle at vestibular level between both molars and group II presented a linear SSRO towards the basilar border. In both groups a standard osteosynthesis was performed with a 2.0 system plate and four monocortical screws, establishing sub-groups according to the degree of mandibular advancement: group A without advancement, group B with an advancement of 3 mm, and group C with advancement of 7 mm. Hemimandibles were subjected to a vertical load in the Instron machine until reaching peak load with failure, recording the value of the load and displacement. The data were analyzed with a t-test to establish statistical significance, considering p<0.05. The results showed that group II presented the best response to the compressive load, tolerating the highest load values. These results were observed in almost all the groups with statistically significant differences (p<0.05). By contrast, group I presented torsional forces prior to reaching system failure. It can be concluded that the osteotomy design influences mechanical resistance and that the linear SSRO offers the best mechanical resistance.

A descriptive study of the oral status in subjects with Sjögren's syndrome.

Sjögren's Syndrome (SS) is an autoimmune pathology of varying prevalence. Its involvement in exocrine glands requires that greater attention be paid to patients' oral health. A cross-sectional study was designed to assess the oral health of subjects with SS in constant medical follow-ups. Variables such as the presence of periodontal infections, decay and alterations in the oral mucosa were analyzed, and the individual's salivary flow was measured. The data were analyzed descriptively and with the chi-squared test, considering p<0.05 as statistically significant. 35 subjects of both sexes were studied, aged between 25 and 82 years, with an age average of 53.9 years; they presented on average 7.9 years after the initial diagnosis. The subjects reported a dental check-up every 6 months in only 9% of cases, whereas the rest had one every 1 or 2 years. All the subjects recounted presenting with dry mouth and associated significantly the ingestion of fluids and teeth brushing to improve the sensation of dryness. The salivary flow was objectively seen to be compromised, showing a significant reduction in those with more time since diagnosis of the disease; more than 90% of subjects exhibited periodontal inflammation and a high level of caries. The mucosa presented a low level of pathology. In conclusion, education in oral health is imperative for subjects with this pathology and more frequent check-ups may be useful in decreasing the levels of oral pathology.

Bacterial contamination along implant-abutment interface in external and internal-hex dental implants.

The aim of this research was to evaluate bacterial contamination along the implant-abutment interface in relation to the size of the interface. 80 brand name implants were used, 40 internal-hex and 40 external-hex. The implants were handled in a sterile atmosphere inside a box, where they were inoculated with 0.3 µl of the Streptococcus sanguis ATCC10556 bacterium in the interior and the abutment was immediately installed with a torque of 30 Ncm for the external-hex and 20 Ncm for the internal-hex; the system was included in an Eppendorf control for 30 seconds and then placed in an Eppendorf control for 30 days. The implants were removed and assessed under a scanning electron microscope while the Eppendorf controls were bred in blood agar to analyze the colonies formed. The data were analyzed using the Chi-squared, Kruskal-Wallis and Mann-Whitney tests, considering a value of p<0.05 to obtain statistical significance. Five implants were excluded due to probable external contamination. Microspaces of up to 86.8 µm were observed in the external-hex implants and up to 53.9 µm in the internal-hex implants with no significant differences between the different systems being observed (p>0.05). The contamination observed was produced mainly in the external-hex implants and statistically significant differences were observed between the different hex systems from the same company. No significant differences were observed between interface size and bacterial contamination. Within our limitations, there was no relation between the size of the implant-abutment interface and bacterial contamination with Streptococcus sanguis ATCC10556.

TMJ function after partial condylectomy in active mandibular condylar hyperplasia.

Condylar hyperplasia is a frequent pathology that causes severe facial asymmetries. The partial condylectomy generally halts the disease. The aim of this research was to examine post-condylectomy TMJ function; 14 patients were included in this study, 6 male and 8 female. The average age was 21 years old. In all, the partial condylectomy was performed with preauricular or endaural access and the osteotomy were performed with drills, saw or an ultrasonic system. The patients were assessed with 3 or more time after surgery and were considering maximum mouth opening, right and left lateralities, presence of pain, noises, alterations in the facial nerve (VII) and esthetic alteration from the scar. The analysis was performed with the visual analog scale (VAS) and with a 7 cm metallic rule. Data analysis was descriptive plus chi-square test considering p value < 0.05 for statistical differences. With an average of 11 month after surgery, the results showed that the open mouth (over 35 mm) and lateralities (average 9 mm for the both right and left side) were normal and without statistical differences between the right or left side. Noise was observed in 3 patients and pain was observed in two patients with level 2 and 1 (VAS score). Scar was not related to problem with patient and the temporal branch of facial nerve was observed with limitations but without problem for patients. It can be concluded that the condylectomy is a safe and effective procedure with low morbidity for patients.

Análisis químico de la superficie de los implantes de titanio comercialmente puro a través de espectroscopía de fotoelectrones por rayos-x (xps) / Chemical analysis of pure titanium commercial implants through x-ray (xps) photoelectron spectroscopy

Este trabajo tiene como objetivo analizar, químicamente la superficie de implantes de titanio comercialmente puro, utilizados actualmente en la odontología. Fueron seleccionados ocho implantes de las siguientes marcas: Conexão ­ Sistema de Prótesis; Lifecore - Biomedical; AS Technology y S ­ Serson Internacional. Las muestras presentaron tratamiento de superficie a través de las técnicas de ataque ácido (Conexão) y plasma spray de titanio (Lifecore - Biomedical; AS Technology y S ­ Serson International). Fueron divididas en cuatro grupos, conteniendo dos implantes del mismo lote de cada fabricante. Los análisis fueron realizados a través de espectroscopía de fotoelectrones excitada por rayos-X (XPS). Los resultados de los análisis químicos mostraron los elementos de titanio (Ti), oxígeno (O), silicio (Si), zinc (Zn), aluminio (Al) y carbono (C). Se puede concluir que hay impurezas en las superficies de los implantes, aunque se necesitan más trabajos que relacionen la presencia de estos compuestos y su interferencia en la oseointegración.

This work aims to analyze chemically the surface of pure titanium commercial implants, currently used in dentistry. Eight implants were selected from the following manufacturers: Conexão ­ sistema de prótesis; Lifecore - Biomedical; as technology and s ­Serson International. The samples showed surface treatment through acid attack techniques (conexão) and titanium plasma spray (Lifecore - Biomedical; technology as and s-Serson International), being divided into four groups containing two implants of the same batch of each manufacturer. Analyses were performed by x- ray excited (XPS) photoelectron spectroscopy. The results of chemical analysis showed the elements Titanium (Ti), Oxygen (O), Silicon (Si), Zinc (Zn), Aluminum (Al) and Carbon (C). It can be concluded that there are impurities in the implant surface, although further studies are needed that associate the presence of these compounds and their interference in osseointegration.

New bone formation in a bone defect associated to dental implant using absorbable or non-absorbable membrane in a dog model.

The aim of this research was to determine the bone formation capacity in fenestration defects associated with dental implants using absorbable and non-absorbable membranes. Six dogs were used in the study. In both tibias of each animal 3 implants were installed, and around these 5 mm circular defects were created. The defects were covered with absorbable membranes (experimental group 1), non-absorbable membranes (experimental group 2), and the third defect was not covered (control group). At 3 and 8 weeks post-surgery, the animals were euthanized and the membranes with the bone tissue around the implants were processed for histological analysis. The statistical analysis was conducted with Tukey's test, considering statistical significance when p<0.1. Adequate bone repair was observed in the membrane-covered defects. At 3 weeks, organization of the tissue, bone formation from the periphery of the defect and the absence of inflammatory infiltrate were observed in both experimental groups, but the defect covered with absorbable membrane presented statistically greater bone formation. At 8 weeks, both membrane-covered defects showed adequate bone formation without significant differences, although they did in fact present differences with the control defect in both periods (p>0.1). In the defects without membrane, continuous connective tissue invasions and bone repair deficiency were observed. There were no significant differences in the characteristics and volume of the neoformed bone in the defects around the implants covered by the different membranes, whereas the control defects produced significantly less bone. The use of biological membranes contributes to bone formation in three-wall defects.

Surgical treatment of frontal sinus fracture sequelae with methyl methacrylate prosthesis.

Inappropriate treatment of fractures of the frontal sinus can lead to serious complications. These fractures are often associated with soft tissue injuries and loss of bony structures. This case report shows the use of methyl methacrylate frontal prosthesis to treat a sequel of frontal sinus fracture; surgical options are discusses and one-year follow-up is present to show stability and good cosmetic result.

Maxillary sinus floor augmentation using blood without graft material. Preliminary results in 10 patients.

PURPOSE: The maxillary sinus lift is recognized and stable, and there have been different innovations to optimize the technique. The aim of this study was to investigate the maxillary sinus lift technique with the use of a blood clot and without the use of a bone graft. MATERIALS AND METHODS: Ten patients were recruited for a unilateral sinus lift; patients without sinus pathology or other contraindication were selected. The maxillary sinus was accessed conventionally under local anesthesia followed by an osteotomy and a 1-cm(2) bony window access. The sinus membrane was detached and the window was repositioned above and stabilized with a 12- or 14-mm osteosynthesis screw introduced through the alveolar ridge. Dental implants were installed in the second surgical stage. Standardized panoramic radiographic checks were performed at every stage. RESULTS: Seven completely edentulous patients and 3 partially dentate patients were treated surgically. From the first to the second surgery, a bone gain of 2.37 mm was obtained, although loss of bone height was observed in 1 completely edentulous patient. In 7 patients, it was not possible to install the implants owing to insufficient bone height or inadequate bone quality. CONCLUSION: The protocol used in this investigation failed in the bone increase required for implant installation.

Pattern and treatment of mandible body fracture.

The aim of this research was to study of treatment of mandibular body fractures (MBF). A retrospective study of 66 patients with mandibular body fracture was realized with subjects was present clinical and image diagnosis;were analyzed socio-demographic variables, etiology, sign and symptoms of fracture, type of treatment and complications. Was executed a statistical and descriptive analysis with Chi-square with statistical significance with p<0.05. The average age was 34 year with 55 male patient; the more common etiology were physical violence and motorcycle accident. The 45.5% present only MBF; patients with multiple fractures show clinical relations between MBF and contra lateral mandibular angle fracture; 54 patients were treated with open reduction without statistical relations with symptoms (p=0.244) or displacement of fracture (p=0.309); the 54.2% of surgical cases present an extraoral approach, using the intraoral approach when the fracture present poor displacement (p=0.0074); the complications more common were suture dehiscence and infections of surgical site. We conclude that the initial choose of treatment was not related to variables analyzed; when exist a minor displacement of MBF can be indicated an intraoral approach for reduction and fixation technique.

Expansão cirúrgica de rebordo alveolar com instalação imediata de implantes / Edentulous ridge expansion with simultaneous implant placement

Introdução: após a perda dentária, o processo alveolar sofre atrofia gradativa, impossibilitando, em casos extremos, a reabilitação com implantes dentários. Objetivo: relatar um caso clínico de instalação de implantes imediatos em maxila edêntula atrófica, após aplicação da técnica de expansão cirúrgica do rebordo alveolar (ECR) na região anterior e levantamento do assoalho do seio maxilar (LS) nas regiões posteriores, em conjunto com enxerto ósseo autógeno removido do ramo ascendente da mandíbula. Conclusão: a ECR e o LS são alternativas viáveis, seguras e previsíveis para o aumento da espessura e altura do rebordo alveolar com finalidade reabilitadora.

Uso de guía de metil-metacrilato fabricados en biomodelo de poliuretano para el tratamiento tardío de fractura panfacial / The use of metil-metacrilate guide manufactured on biomodel of polyurethane for late treatment of panfacial fracture

El manejo de las secuelas faciales por fracturas no tratadas ha tenido un crecimiento importante debido al uso de los biomodelos. Estos permiten optimizar la cirugía, disminuir los tiempos quirúrgicos y mejorar los resultados. El presente articulo muestra un caso de secuela de fractura facial tratada con osteotomías con ayuda de guías quirúrgicos fabricados en base a un biomodelo operado; se presenta el resultado postoperatorio de 6 meses con una resolución adecuada.

The management of facial sequel by facial fractures non-treated nowadays presents an important expansion by the use of biomodels. This system can be used for reduce surgical time, optimize surgical protocol and improve outcomes. This paper presents a sequel case for facial fracture treated with bone osteotomy using surgical guide manufactured base on biomodels operated; is showing the postoperative 6 month follow-up with good results.

Análisis topográfico de la superfície de implantes de titanio comercialmente puro a través de microscopía electrónica de barrido / Topographic analysis of the surface of commercially pure titanium implants by scanning electronic microscopy

Este trabajo tiene como objetivo analizar topográficamente la superficie de implantes de titanio comer-cialmente puros. Fueron seleccionados ocho implantes de las siguientes fabricantes: Conexáo - Sistema de Próteses; Lifecore - Biomedical; AS Technology y S - Serson Internacional. Las muestras presentaban tratamiento de la superficies, a través de las técnicas de ataque acido (Conexáo) y plasma spray de titanio (Lifecore-Biomedical; AS Technology y S -Serson International), siendo divididas en cuatro grupos, conteniendo dos implantes del mismo lote de cada fabricante. Los análisis fueron realizados a través de microscopia electrónica de barredura (MEB). Los estudios a través de MEB revelaron la topografía rugosa de la superficie y la uniformidad de las áreas entre las roscas de los implantes. Se puede concluir que todas las muestras presentaron rugosidad en la superficie, con diferencias en la micromorfología entre todos los implantes.

The aim of this research is to analyze the pure titanium dental implant surface. An 8 implant device of Conexáo - Sistema de Próteses; Lifecore - Biomedical; AS Technology y S - Serson Internacional was selected. The simple presented surface treatment with acid attack or titanium plasma spray, being analyzed in 4 groups with two implants in each. Those analyzed were realized with a scanning electron microscope showing the topography and structure between different part of the implant. It was concluded that all implant systems show surface roughness with differences in the micro-morphology among all implant groups.

Bacterial adhesion and colonization differences between zirconia and titanium implant abutments: an in vivo human study.

PURPOSE: Several parameters have been described for determining the success or failure of dental implants. The surface properties of transgingival implant components have had a great impact on the long-term success of dental implants. The purpose of this study was to compare the tendency of two periodontal pathogens to adhere to and colonize zirconia abutments and titanium alloys both in hard surfaces and soft tissues. METHODS: Twelve patients participated in this study. Three months after implant placement, the abutments were connected. Five weeks following the abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsies were performed. The abutments and gingival biopsies taken from the buccal gingiva were analyzed using real-time polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated using the sessile water drop method before replacement. Data analyses used the Mann Whitney U-test, and P-values below 0.05 find statistical significance. RESULTS: The present study showed no statistically significant differences between the DNA copy numbers of A. actinomycetemcomitans, P. gingivalis, and total bacteria for both the titanium and zirconia abutments and the biopsies taken from their buccal gingiva. The differences between the free surface energy of the abutments had no influence on the microbiological findings. CONCLUSIONS: Zirconia surfaces have comparable properties to titanium alloy surfaces and may be suitable and safe materials for the long-term success of dental implants.

Reconstrução cirúrgica de fratura fronto-naso-órbito-etmoidal / Surgical reconstruction of a frontonasal orbital-etmoidal fracture

As fraturas do seio frontal são originadas a partir de acidentes de grande intensidade, que incluem acidentes automobilísticos, agressões físicas, acidentes esportivos e quedas. Normalmente, estão associadas com fraturas do terço médio da face, incluindo fraturas maxilares, naso-órbito-etmoidais e zigomáticas. Várias modalidades de tratamento têm sido propostas para reconstrução das fraturas fronto-naso-órbito-etmoidais, incluindo fixação dos fragmentos ósseos com placas e parafusos, reconstrução com enxertos ósseos e implante de malhas de titânio. No caso ora apresentado, utilizou-se do acesso bicoronal para reconstrução da parede anterior do seio frontal e restabelecimento do contorno fronto-naso-órbito-etmoidal, sendo utilizado enxerto ósseo de calota craniana para esse fim. Verificou-se a integridade do ducto fronto-nasal, não havendo necessidade de canulização deste. Esse procedimento é importante diretriz no plano de tratamento, uma vez que determina a obliteração ou canulização do ducto. Nenhuma complicação ou sequela foi observada na proservação de aproximadamente um ano. A proservação por longos períodos pós-operatórios é importante para avaliação de possíveis complicações.

Frontal sinus fractures are originated from high intensity accidents, including automobile accidents, altercations, sports accidents and falls. Normally, they are associated with fractures of the middle third of the face, including maxillary, nasal-orbital-etmoidal and zygomatic fractures. Several treatment modalities have been proposed to reconstruct fronto-nasal-orbital-etmoidal fractures, including fixation of bone fragments with plates and screws, reconstruction with bone grafts and titanium mesh implants. In the case here presented, bicoronal access was used to reconstruct the anterior wall of the frontal sinus and to reestablish the fronto-nasal-orbital-etmoidal contour, using a bone graft from the cranial cap for this purpose. The integrity of fronto-nasal duct was verified, and there was no need to canalize it. This procedure is an important guideline in the treatment plan, since it determines obliteration or canalization of the duct. After one year of follow-up, no complication or sequela was observed. Long periods of post-operative follow up are very important to evaluate possible complications.

Enucleação de ameloblastoma mandibular multicístico / Multicystic enucleation of mandibular ameloblastoma

Ameloblastomas são tumores benignos, localmente invasivos e altamente recidivante. É um tumor odontogênico, caracterizado pela proliferação do epitélio ameloblástico em um estroma fibroso. O presente trabalho relata um caso de ameloblastoma mandibular, em que foi realizada a enucleação total com escarificação marginal e reconstrução por meio de placa e parafusos de titânio.

Ameloblastomas are benign tumors with locally invasive characteristics and high recurrence episodes. It is an odontogenic tumor characterized by fibrous epithelium ameloblastic proliferation into the stromal tissue. This paper presents a case of mandibular ameloblastoma, enucleation and mandibular reconstruction with titanium plate and screws.