Renato Sawazaki

Incidence and patterns of mandibular condyle fractures

PURPOSE The aim of the present study was to retrospectively evaluate the epidemiologic characteristics of the prevalence, type, and treatment modalities of condylar fractures of the mandible. PATIENTS AND METHODS Data were collected from patients during an 8-year period (1999 to 2007). The data recorded included demographic data, etiology, diagnosis, type, dislocation, use of protective devices, state of the dentition, associated facial and general trauma, soft tissue lesions, treatment methods, and the interval between trauma and treatment. Data analysis included a descriptive analysis, chi(2) test, Fishers exact test, t test, and Kruskal-Wallis test. RESULTS During the 8-year period, 209 unilateral fractures and 54 bilateral fractures were treated, with a male/female ratio of 3.05:1 and a mean age of 28.4 years, for a total of 317 condylar fractures. Male gender was significantly associated with the presence of a condylar fracture (P < .05). The most common cause of condylar fractures was road traffic accidents (57.8%). Of the 317 fractures, 300 were classified as simple fractures, and 249 fractures were not displaced. Protective devices significantly decreased the number of condylar fractures occurring from road traffic accidents (P < .05). Symphysis fractures were significantly associated with both unilateral and bilateral fractures of the mandibular condyle (P < .05). Subcondylar displaced fractures were significantly associated with surgical treatment (P < .05). CONCLUSIONS Young adults were involved in most of the accidents. Road traffic accidents were the main cause of condylar fractures. The mandatory use of safety helmets and seatbelts and education of those using the road are essential to decrease the number of facial fractures.

Surgical Approaches and Fixation Patterns in Zygomatic Complex Fractures

The aim of this research was to analyze the surgical approaches and methods of rigid fixation used to treat zygomatic complex (ZC) fractures over a 10-year period. One hundred fifty-three patients who underwent surgery to treat ZC fractures between 1999 and 2008 were retrospectively evaluated. Demographic information, signs, and symptoms of the fractures, classification, surgical approaches, and methods of internal fixation were obtained from the medical records. The data were analyzed using statistical descriptive analysis and &khgr;2 test (P < 0.05). The mean age of the sample was 31 years, and males were predominant (82.3%). In 60.1% of the patients, one surgical approach was used to treat the ZC fractures, whereas 2 surgical approaches were used in 24.8% of the patients. The zygomaticomaxillary buttress was fixed in 86.9% of the patients, followed by infraorbital rim fixation and zygomaticofrontal. There was a statistical significance between fracture displacement and surgical approach for the infraorbital rim (P < 0.0001) and zygomaticofrontal suture (P < 0.0001). Considering that adequate reduction and fixation should be performed and that we try to minimize the amount of scarring, the intraoral zygomaticomaxillary buttress approach is the first choice to treat ZC fractures. In cases of displacement bigger than 5 mm, approaches to 3 of 4 points of the ZC are mandatory to reduce the fractures. The infraorbital rim and zygomaticofrontal suture approaches are indicated to treat displaced fractures.

A Rare Case of Mediastinal and Cervical Emphysema Secondary Mandibular Angle Fracture: A Case Report

Subcutaneous emphysema in the head and neck is a well-known clinical entity usually associated with trauma to the facial bones and dentoalveolar surgery. Cervical, retropharyngeal, and mediastinal emphysema is a more severe manifestation associated with traumatic injuries to the facial bones and aerodigestive tract and is associated with potentially severe and even life-threatening complications. Mandibular fracture as a cause of mediastinal emphysema is rare, with only 4 cases having been reported in the literature. Mediastinal and cervical emphysema has been described after other maxillofacial injuries such as zygomaticomaxillary complex fractures, orbital blow-out fractures, naso-orbito-ethmoid fractures, and isolated maxillary sinus fractures. Iatrogenic emphysema has been reported and includes the use of air turbine dental drills, CO2 laser, O2 cryomachine, air abrasive system, endotracheal/ entilation in patients after dental surgical proceures, and endodontic treatment. Pneumomediastinum has been documented after orthognathic surgery and acute, transient episodes of respiratory bstruction, such as that produced by the Valsalva aneuver, violent coughing, and emesis.

Variables related to surgical and nonsurgical treatment of zygomatic complex fracture.

The aim of this retrospective research was to establish the association between variables for the surgical treatment of zygomatic complex (ZC) fractures. In a 10-year period, 532 patients were examined for ZC fractures. The medical records of patients were analyzed to obtain information related to sociodemographic characteristics, trauma etiology, sign and symptoms of patients, and surgical or nonsurgical treatment. Statistical analysis was performed using &khgr;2 test with statistical significance of P < 0.05. Most fractures were sustained by subjects between 21 and 40 years of age (55.8%), being principally men (80.1%), and 153 patients underwent surgery (28.8%). Surgical treatment of ZC fractures was statistically associated to the presence of other facial fractures (P = 0.004), alteration of occlusion (P = 0.0001; probably due to jaw fractures), presence of the comminuted fractures (P = 0.0002), and infraorbital nerve sensory disturbances (P = 0.003). A mixture of complex variables can be associated to surgical treatment; however, variables as comminuted fracture and alteration of occlusion were associated to surgical treatment indications.

Comparative study between 2 methods of mounting models in semiadjustable articulator for orthognathic surgery.

PURPOSE Compare the traditional method of mounting dental casts on a semiadjustable articulator and the new method suggested by Wolford and Galiano, 1 analyzing the inclination of maxillary occlusal plane in relation to FHP. MATERIALS AND METHODS Two casts of 10 patients were obtained. One of them was used for mounting of models on a traditional articulator, by using a face bow transfer system and the other one was used to mounting models at Occlusal Plane Indicator platform (OPI), using the SAM articulator. After that, na analysis of the accuracy of mounting models was performed. The angle made by de occlusal plane and FHP on the cephalogram should be equal the angle between the occlusal plane and the upper member of the articulator. RESULTS The measures were tabulated in Microsoft Excell(®) and calculated using a 1-way analysis variance. Statistically, the results did not reveal significant differences among the measures. CONCLUSION OPI and face bow presents similar results but more studies are needed to verify its accuracy relative to the maxillary cant in OPI or develop new techniques able to solve the disadvantages of each technique.

¿Existen Diferencias en la Morfometría Mandibular de Pacientes Candidatos a Cirugía Ortognática? Parte 2: Influencias del Género

Las caracteristicas faciales son individuales siendo asociadas a influencias geneticas y ambientales; es posible identificar claras diferencias entre los padrones faciales de hombres y mujeres, donde las deformidades dentofaciales (DDF) van a influenciar en las indicaciones quirurgicas, tecnicas quirurgicas y en los resultados esteticos finales. Se realizo un estudio de cohorte con pacientes que consultaron por cirugia ortognatica entre los anos 2002 y 2008 en la Division de Cirugia Oral y Maxilofacial de la FOP-UNICAMP. Se estudio las radiografias panoramicas utilizadas en la planificacion quirurgica relacionando el genero del paciente con las caracteristicas morfometricas mandibulares especificamente asociadas a las tecnicas quirurgicas empleadas en la correccion de DDF; fueron realizadas evaluaciones descriptivas y estadisticas con la prueba Chi-Cuadrado con significancia estadistica cuando p<0,05. Cuarenta y seis pacientes fueron estudiados, siendo 26 pacientes del sexo femenino y 20 pacientes del sexo masculino. No fue posible identificar diferencias estadisticas en la morfometria mandibular en los dos grupos estudiados. En el analisis descriptivo las diferencias proporcionales entre los grupos fueron minimas. Finalmente, podemos senalar que no existen diferencias en pacientes brasilenos del sexo masculino y femenino cuando son comparadas proporciones morfometricas mandibulares.

Comparative in vitro mechanical evaluation of techniques using a 2.0 mm locking fixation system for simulated fractures of the mandibular body

PURPOSE To perform a comparative evaluation of the mechanical resistance of simulated fractures of the mandibular body which were repaired using different fixation techniques with two different brands of 2.0 mm locking fixation systems. MATERIALS AND METHODS Four aluminum hemimandibles with linear sectioning simulating a mandibular body fracture were used as the substrates and were fixed using the two techniques and two different brands of fixation plate. These were divided into four groups: groups I and II were fixed with one four-hole plate, with four 6 mm screws in the tension zone and one four-hole plate, with four 10 mm screws in the compression zone; and groups III and IV were fixed with one four-hole plate with four 6 mm screws in the neutral zone. Fixation plates manufactured by Tóride were used for groups I and III, and by Traumec for groups II and IV. The hemimandibles were submitted to vertical, linear load testing in an Instron 4411 servohydraulic mechanical testing unit, and the load/displacement (3 mm, 5 mm and 7 mm) and the peak loads were measured. Means and standard deviations were evaluated applying variance analysis with a significance level of 5%. RESULTS The only significant difference between the brands was seen at displacements of 7 mm. Comparing the techniques, groups I and II showed higher mechanical strength than groups III and IV, as expected. CONCLUSION For the treatment of mandibular linear body fracture, two locking plates, one in the tension zone and another in the compression zone, have a greater mechanical strength than a single locking plate in the neutral zone.

Estudio Descriptivo de los Accesos Quirúrgicos Utilizados en el Tratamiento de Fracturas del Complejo Zigomático Orbitario

El objetivo del presente estudio fue evaluar los accesos quirurgicos utilizados para el abordaje del complejo zigomatico orbitario (CZO) y arco zigomatico (AZ). Fue disenado un estudio de tipo retrospectivo, evaluando las fichas clinicas de pacientes atendidos entre el 1 de Abril del ano 1999 y el 31 de Diciembre del ano 2008. Fueron estudiadas variables sociodemograficas y caracteristicas de la fractura, tales como presencia de mas de una fractura facial y desplazamiento del fragmento oseo. Se realizo un estudio descriptivo de los diferentes accesos quirurgicos utilizados y cuando fue necesario se estudio la asociacion estadistica con la prueba chi-cuadrado para variables nominales, estableciendo significancia si p<0,05. Ciento cincuenta y tres pacientes fueron sometidos a tratamiento quirurgico de fractura de CZO con 251 accesos quirurgicos. El acceso mas efectuado fue el intrabucal, seguido del acceso subciliar y supraciliar. Siempre existio mayor utilizacion de accesos para pilar zigomaticomaxilar, seguidos por accesos para reborde infraorbitario y sutura frontozigomatica, con pocas diferencias entre ellos. No fue posible encontrar asociacion estadistica entre las variables estudiadas y la cantidad de accesos para el tratamiento quirurgico de fracturas de CZO. Los accesos quirurgicos deben responder a las necesidades individuales de cada caso, intentando obtener indicaciones precisas, mas que preferencias individuales de cada cirujano.