Estudo comparativo entre dois programas de computador (Dolphin Imaging® e Nemotec®) e método manual para análises cefalométricas de pacientes com deformidade dentofacial Padrão II / Comparative study of two computer software programs (Dolphin Imaging® and Nemotec®) and a manual method of cephalometric analysis for patients with dentofacial deformity Class II

Este estudo analisou traçados digitais obtidos por dois programas de computador (Dolphin Imaging® e Nemotec®) em comparação aos obtidos pelo método manual nas análises cefalométricas SNA, SNB, Co-A, Co-Gn, altura facial anterior, A-Nperp, Pg-Nperp e plano mandibular. 30 pacientes leucodermas, portadores de retrognatismo mandibular, foram avaliados e submetidos à cirurgia ortognática para correção da deformidade por meio da osteotomia sagital do ramo mandibular. Os traçados cefalométricos foram realizados em telerradiografias laterais obtidas uma semana antes da cirurgia. O método Manual e o Nemotec® apresentaram excelente confiabilidade em todas as medidas. Por outro lado, o método Dolphin Imaging® apontou baixa confiabilidade nas medidas altura facial anterior, Co-A e Co-Gn. Nas medidas A-Nperp, Pg-Nperp, Plano md, SNA e SNB, não houve diferença entre três métodos estudados. Na medida altura facial anterior, houve diferença entre os métodos Dolphin Imaging® e Nemotec®, mas não foram observadas diferenças em relação ao método manual. Nas medidas Co-A e Co-Gn, foi observado que o método Dolphin Imaging® apresentou média significativamente inferior aos demais métodos estudados. No método manual, somente as medidas Co-Gn, Pg-Nperp e SNB confirmaram o diagnóstico de retrognatismo mandibular, tendo o programa Nemotec® apresentado resultados melhores que o programa Dolphin Imaging®... (AU)

This study analyzed digital tracings obtained by two different computer software programs (Dolphin Imaging® and Nemotec®) and compare them to the manual method using cephalometric measurements SNA, SNB, Co-A, Co-Gn, anterior facial height, A-Nperp, Pg-Nperp and mandibular plane. Thirty Caucasian patients exhibiting mandibular retrognathia were analyzed and were submitted to orthognathic surgery to correct the deformity by bilateral sagittal split osteotomy. The cephalometric tracings were performed with lateral radiographs that were obtained a week prior to the surgery. The manual method and the Nemotec® software exhibited an excellent reliability in all measurements. However, the Dolphin Imaging® method exhibited low reliability in the anterior facial height, Co-A and Co-Gn measurements. For the measurements of A-Nperp, Pg-Nperp, Mandibular plan, SNA and SNB, there were no significant differences between the three methods studied. For the anterior facial height measurement, a statistically significant difference was found between the Dolphin Imaging® and Nemotec® methods, although not in relation to the manual method. For the Co-A and Co-Gn measurements, the Dolphin Imaging® method exhibited a significantly lower mean than the other methods studied. In manual method, only the Co-Gn, Pg-Nperp and SNB measurements confirmed the diagnosis of mandibular retrognathia and Nemotec® software provided better results than Dolphin Imaging®... (AU)

Influence of degree of edentulism in mandible fractures / Influência do grau de edentulismo em fraturas mandíbulas

Objective ­ To characterize epidemiologically the aspects of incidence, treatment and complications of mandibular fractures in dentate, partially dentate and edentulous patients. Methods ­ Data were collected from medical records of patients seen by the department of Oral and Maxillofacial Surgery, Piracicaba School of Dentistry/UNICAMP, from January 1999 to October 2009. Results ­ Were selected 738 adult patients, grouped into three age groups (18 to 30 years, 31-64 years and over 64 years), whose degree of edentulism was informed, being 330 dentition (45%), 367 partially serrated (50%) and 41 edentulous (5%). The ratio between male and female was 4:1, mean age of 31 years, with higher incidence in caucasians, and 81% were economically active. The most common causes were traffic accidents (54%), followed by assault (20%), falls (15%), sports accidents (4%) and work (4%). Condylar fractures accounted for 29% of all fractures, followed by fractures of the body (25%), symphysis (24%) and angle (19%). The only significant difference between the sites of fracture was found in the edentulous, which presented a low incidence of angle fractures. Conclusions ­ It was observed that this population, homogeneous as to the cultural and socio-environmental factors, the dentate, partially dentate and edentulous behaved similarly as to the mandibular fractures resulting from trauma energies of similar intensities.

Objetivo ­ Caracterizar epidemiologicamente os aspectos de incidência, tratamento e complicações de fraturas mandibulares em pacientes dentados, parcialmente dentados e edêntulos. Métodos ­ Os dados foram coletados de prontuários de pacientes atendidos pelo departamento de Cirurgia Oral e Maxilofacial, Faculdade de Odontologia de Piracicaba/UNICAMP, de janeiro de 1999 a outubro de 2009. Resultados ­ Foram selecionados 738 pacientes adultos, agrupados em três faixas etárias (18 a 30 anos, 31-64 anos e mais de 64 anos), cujo grau de edentulismo foi informado, sendo 330 dentições (45%), 367 parcialmente serrilhadas (50%) e 41 edêntulas (5%). A proporção entre homens e mulheres foi de 4:1, idade média de 31 anos, com maior incidência em caucasianos e 81% economicamente ativas. As causas mais comuns foram os acidentes de trânsito (54%), seguidos pelo assalto (20%), quedas (15%), acidentes esportivos (4%) e trabalho (4%). As fraturas condilares representaram 29% de todas as fraturas, seguidas de fraturas do corpo (25%), sínfise (24%) e ângulo (19%). A única diferença significativa entre os locais de fratura foi encontrada no edêntulo, que apresentou baixa incidência de fraturas angulares. Conclusões ­ Observou-se que esta população, homogênea quanto aos fatores culturais e socioambientais, dentada, parcialmente dentada e edêntula, comporta-se de forma semelhante às fraturas mandibulares resultantes de energias de trauma de intensidades semelhantes.

Evaluation of cyclic and linear mechanical resistance of prebent and manually-bent plates used for maxillary advancement in orthognathic surgery.

The aim of the present study was to compare prebent and manually-bent plates used in maxillary advancement. The prebent plates were fixed in polyurethane blocks for the linear test and aluminium blocks for the cyclic test, and the manually-bent plates were fixed in polyurethane and aluminium blocks. The linear load tests were done using an Instron® 4411 mechanical testing machine and the cyclic test with an Instron® E3000 testing machine. The linear mechanical test showed that there was no significant difference between the plates. In the cyclic test the prebent plates reached the limit of 500000 cycles without fracturing whereas the manually-bent plate group fractured before reaching the limit of cycles (p=0.008). The decision to use prebent or manually-bent plates during operations should be influenced by the production of the bends and their consequent brittleness.

Mechanical and microstructural properties of fixation systems used in oral and maxillofacial surgery.

OBJECTIVES: This paper aims to evaluate in vitro the mechanical and microstructural properties of internal fixation systems used in oral and maxillofacial surgeries. MATERIALS AND METHODS: Four brands of internal fixation systems (screws and 4-hole straight plates) were selected and assigned to four groups: G1 Leibinger®, G2 Tóride®, G3 Engimplan®, and G4 Medartis®. The systems were submitted to Vickers hardness testing, metallographic and interstitial elements chemical composition analyses. Data were submitted to ANOVA and Tukey's test for statistical analysis. RESULTS: Plates in groups 1, 2, and 3 showed similar microstructure and mechanical properties, different from those in G4 revealing larger grains. In all groups, the screws showed similar microstructure, with uniform arrangement and size of grains; the screws showed higher hardness values than those observed for the plates. CONCLUSIONS: The results indicate that all materials tested are adequate for use in oral maxillofacial surgeries.

Analysis of residual stress and hardness in regions of pre-manufactured and manual bends in fixation plates for maxillary advancement.

The aim of this study was to analyze, through Vickers hardness test and photoelasticity analysis, pre-bent areas, manually bent areas, and areas without bends of 10-mm advancement pre-bent titanium plates (Leibinger system). The work was divided into three groups: group I-region without bend, group II-region of 90° manual bend, and group III-region of 90° pre-fabricated bends. All the materials were evaluated through hardness analysis by the Vickers hardness test, stress analysis by residual images obtained in a polariscope, and photoelastic analysis by reflection during the manual bending. The data obtained from the hardness tests were statistically analyzed using ANOVA and Tukey's tests at a significance level of 5 %. The pre-bent plate (group III) showed hardness means statistically significantly higher (P < 0.05) than those of the other groups (I-region without bends, II-90° manually bent region). Through the study of photoelastic reflection, it was possible to identify that the stress gradually increased, reaching a pink color (1.81 δ / λ), as the bending was performed. A general analysis of the results showed that the bent plate region of pre-bent titanium presented the best results.

Mechanical and photoelastic analysis of four different fixation methods for mandibular body fractures.

OBJECTIVE: The aim of the present study was to compare four methods of fixation in mandibular body fractures. STUDY DESIGN: Mechanical and photoelastic tests were performed using polyurethane and photoelastic resin mandibles, respectively. The study groups contained the following: (I), two miniplates of 2.0 mm; (II) one 2.0 mm plate and an Erich arch bar; (III) one 2.4 mm plate and an Erich arch bar, and (IV) one 2.0 mm plate and one 2.4 mm plate. The differences between the mean values were analyzed using Tukey's test, the Mann-Whitney test and the Bonferroni correction. RESULTS: Group II recorded the lowest resistance, followed by groups I, IV and III. The photoelastic test confirmed the increase of tension in group II. CONCLUSION: The 2.4 mm system board in linear mandibular body fractures provided more resistance and the use of only one 2.0 mm plate in the central area of the mandible created higher tension.

Development plates for stable internal fixation: Study of mechanical resistance in simulated fractures of the mandibular condyle.

OBJECTIVE: To develop Y-shaped plates with different thicknesses to be used in simulated fractures of the mandibular condyle. Ten plates were developed in Y shape, containing eight holes, and 30 synthetic polyurethane mandible replicas were developed for the study. MATERIAL AND METHODS: The load test was performed on an Instron Model 4411 universal testing machine, applying load in the mediolateral and anterior-posterior positions on the head of the condyle. Two-way ANOVA with Tukey testing with a 5% significance level was used. RESULTS: It was observed that when the load was applied in the medial-lateral plate of greater thickness (1.5 mm), it gave the highest strength, while in the anteroposterior direction, the plate with the highest resistance was of the lesser thickness (0.6 mm). A plate with a thickness of 1.5 mm was the one with the highest average value for all displacements. In the anteroposterior direction, the highest values of resistance were seen in the displacement of 15 mm. CONCLUSION: After comparing the values of the biomechanical testing found in the scientific literature, it is suggested that the use of Y plates are suitable for use in subcondylar fractures within the limitations of the study.

Clinical, radiographic, and histological analyses of calcium phosphate cement as filling material in maxillary sinus lift surgery.

BACKGROUND: The installation of dental implants in the posterior maxilla is often faced with resorbed alveolar processes, resulting from a combination of pneumatization of the maxillary sinus, the effects of periodontal disease, and physiological bone resorption. The sinus lift surgery has been practiced since 1980 with the aim to increase bone height in this region for an implant supported prosthetic rehabilitation, and various filling materials have been used for such. OBJECTIVES: This study aimed to clinically, radiographically, and histologically evaluate a preparation of calcium phosphate cement (Bone Source(®), BS) used as filling material in maxillary sinus elevation surgery. METHODS: Ten patients were operated requiring maxillary sinus graft for future placement of osseointegrated implants. After a period ranging from 9 to 16 months, a clinical evaluation and biopsy of the grafted area in the region adjacent to the axis of the implant to be inserted were performed. RESULTS: Clinically and radiographically, no evidence of resorption/substitution of BS was noticed. Although no patients have had postoperative complications and the material presented fully biocompatible characteristics with woven bone in intimate contact with BS, it was not possible to place any implants due to minimal bone formation and friability of the material. CONCLUSION: It was concluded that despite the osteoconductive capacity of BS, this conventional calcium phosphate preparation does not support sufficient amount of new bone formation that could allow its use as filling material for maxillary sinus floor lift and subsequent dental implant placement.

Perception of oral and maxillofacial surgeons, orthodontists and laypersons in relation to the harmony of the smile.

OBJECTIVE: Harmony is one of the main objectives in surgical and orthodontic treatment and this harmony must be present in the smile, as well as in the face. The aim of the present study was to assess the perceptions of professionals and laypersons in relation to the harmony of the smile of patients with or without vertical maxillary alterations. MATERIALS AND METHODS: Sixty observers (oral and maxillofacial surgeons, orthodontists and laypersons) reported the degree of harmony of six smiles using an objective questionnaire and the participants indicated if there was a need for corrective surgery or not. The classification of observers was recorded on a Likert scale from 1 to 5. Mixed regression was used to determine differences between the three groups. RESULTS: Statistically significant differences were found only for the harmony of the smile between the oral and maxillofacial surgeons and laypersons, with laypersons being more critical when assessing the smile. There was no statistical difference between the other groups for the harmony of the smile or the indication of corrective surgery. The patterns of greater or lesser harmony determined by observers during the smile were similar to those found in the literature as the ideal standard in relation to vertical maxillary positioning. CONCLUSIONS: Laypersons had a tendency to be more critical in relation to facial harmony than surgeons, although no statistical differences were found in the other groups in relation to the harmony of the smile or indication for the corrective surgery. In addition, the patterns of greater or lesser harmony of the smile determined by the participants were similar to those found in the literature as the ideal standard in relation to vertical maxillary positioning. Overall, the present study demonstrates that adequate interaction between surgeons, orthodontists and laypersons is essential in order to achieve facial harmony with orthodontic and/or surgical treatment. CLINICAL RELEVANCE: Opinion of specialists and laypersons about the smile in relation to the vertical positioning of the maxilla.

Biomechanical strength analysis of mini anchors for the temporomandibular joint.

INTRODUCTION: The usage of mini anchors for the treatment of internal derangements of the temporomandibular joint (TMJ) is considered an innovative treatment, and it has presented excellent clinical results in the stabilization of the articular disc. This study aimed to evaluate, through mechanical tensile testing, the resistance of mini anchors for TMJ articular disc repositioning. MATERIALS AND METHODS: Ten thermoplastic polymer poly-ether-ether-ketone (PEEK) mini anchors were tested in artificial polyurethane blocks with a pullout test in a mechanical Instron™ machine, model 4411. The mini anchors were pulled out until failure and the force and displacement were recorded for each specimen. A small standard deviation was noted, which indicated reproducibility. RESULTS: The findings indicate that Cillen™ mini anchors presented a mean force at failure up to 46.1 N with similar values in the scientific literature. Nevertheless, further studies should be conducted for a comparison of PEEK mini anchors with other commercially available anchors, in addition to studies related to PEEK, a scarcely known material in the dentistry field.

Hipertrofia unilateral do músculo master: relato de caso / Unilateral Masseter Muscle Hypertrophy: Case Repor

A hipertrofia do músculo masseter é um crescimento excessivo uni ou bilateral do músculo, de etiopatogenia ainda não definida que, na maioria das vezes, gera um desconforto estético e em alguns casos, funcional. Os indivíduos afetados frequentemente exibem um aumento em volume ósseo em região de ramo e ângulo mandibular e o tratamento pode ser através de métodos cirúrgicos ou não cirúrgicos. A abordagem cirúrgica envolve intervenções que são realizadas, apenas, na musculatura comprometida, na estrutura óssea do ângulo mandibular ou ambos. O presente artigo descreve um caso de hipertrofia unilateral do músculo masseter, onde optou-se pela intervenção cirúrgica intraoral com ressecção de fibras musculares e osteotomia do ângulo mandibular. Após um período de dois meses de acompanhamento, observa-se que a modalidade cirúrgica para tratamento de hipertrofia do masseter está bem indicada pois proporciona ótimo resultado estético... (AU)

Masseter muscle hypertrophy is a unilateral or bilateral enlargement of the masseter muscle, of undefined etiology, which in most cases generates an aesthetic discomfort, and in some cases a functional one as well. The affected individuals often exhibit an increase in bone mass in the region of the branch and mandibular angle, and the treatment can use surgical or nonsurgical methods. The surgical approach involves intervetions performed in either the compromised muscle or the mandibular angle bone structure, or in both. This article describes a case of unilateral masseter muscle hypertrophy, where the surgical resection of the muscle fibers in an intraoral approach and a osteotomy with a reciprocating saw were performed in the mandibular angle region. After a two-month follow-up, it was observed that the surgical approach for the treatment of masseter hypertrophy is well advised, since the aesthetic results are excellent, with similarity to the contralateral side of mandibular angle... (AU)

Biomechanical analysis on diferente fixation techniques for treatment of mandibular body fractures

Aim: To biomechanically analyze two fixation techniques in polyurethane hemi-mandibular bodyfractures, using a universal testing machine. Methods: The study employed 10 polyurethanehemi-mandible replicas, which simulated simple fractures of the mandibular body, divided into twogroups: one group comprised 5 hemi-mandibles with two 2.0 mm system plates in the tension andcompression zones, while the other group contained 5 hemi-mandibles with an Erich bar and a2.0 mm system plate in the tension and neutral zones, respectively. Data were analyzed statisticallyby the Student’s t-test (α=0.05) Results: The test results indicated that the fixation using 2.0 mmsystem plates offered significantly more resistance to the loads and presented significantly largerdisplacement compared to the fixation using just one 2.0 mm system plate and the Erich bar.Conclusions: It may be concluded that the use of two plates in the 2.0 mm system had greatermechanical strength than a single 2.0 mm plate combined with an Erich bar. Clinically, it is knownthat both techniques can provide good results, but patients receiving the combination of Erich barand one plate are required to be more cooperative during the postoperative period, especiallywith respect to the prescribed diet in order to avoid failures in this system.

Evaluation of the use of biomodels in sequelae of maxillofacial trauma / Evaluación de la utilización de biomodelo de secuelas de traumatismo maxilofacial

The use of rapid prototyping technology in Oral and Maxillofacial Surgery has been increasing in the last decade, allowing the management of biomodels from medical image processing as computed tomography in order to obtain a three dimensional model with the same geometric characteristics as the virtual one. The aim of this study is to present the use of biomodels for treatment of maxillofacial trauma sequelae with evaluation of clinical records in a period that varies from January 2000 to December 2010. For diagnosis and surgical planning of maxillofacial sequelae in this period, some 15 prototypes were used, allowing us to determine the treatment planning with more accuracy and to save operating room time.

El uso de tecnología de prototipado rápido en Cirugía Oral y Maxilofacial se ha incrementado en la última década, lo que permite la gestión de los biomodelos de procesamiento de imágenes médicas, como tomografía computarizada para obtener un modelo tridimensional con las mismas características geométricas del virtual. El objetivo de este estudio es presentar el uso de biomodelos para el tratamiento de las secuelas de un traumatismo maxilofacial con la evaluación de las historias clínicas en un período que varía entre enero de 2000 a diciembre de 2010. Para el diagnóstico y la planificación de la cirugía maxilofacial de las secuelas en este período, 15 prototipos fueron utilizados, lo que permite determinar la planificación del tratamiento con más precisión y para ahorrar tiempo de quirófano.