Evaluation of mandibular ramus morphology using computed tomography in patients with mandibular prognathism and retrognathia: relevance to the sagittal split ramus osteotomy.

PURPOSE: The purpose of this study was to evaluate and compare the thickness of the mandibular ramus in patients with mandibular prognathism and retrognathia, as well as to assess the distribution of cancellous bone between the external and internal cortical plates above and posterior to the lingula. PATIENTS AND METHODS: The mandibular ramus of 40 patients, of whom 20 had prognathism and 20 had retrognathia, were evaluated by use of high-resolution computed tomography scanning. RESULTS: The mean thickness of the ramus in the prognathism group was 8.17 mm, which differed significantly from the mean value of 8.88 mm in those with retrognathia (P = .014). The mean vertical distance of the point of fusion between the cortical plates above the lingula was 8.95 mm for patients with prognathism and 9.41 mm for those with retrognathia, which was not a significant difference (P = .364). The mean horizontal distance of the point of fusion between the cortical plates posterior to the lingula was 8.32 mm for patients with prognathism and 9.74 mm for those with retrognathia, which was also not a significant difference (P = .066). CONCLUSIONS: The mandibular ramus is thinner in patients with prognathism than in those with retrognathia. The distance of the point of fusion between the cortical plates above and posterior to the lingula is not influenced by the 2 types of mandibular deformity evaluated in this study. Computed tomography has proven to be a valuable tool to evaluate the morphology of the mandibular ramus.

Anteroposterior position of mandible and perceived need for orthognathic surgery.

PURPOSE: This study investigated the association between the anteroposterior position of the mandible and the perceived need for orthognathic surgery. MATERIALS AND METHODS: Profiles of 2 men, 1 black and 1 white, and 2 women, 1 black and 1 white, were photographed and altered to produce photos with a straight profile and 6 simulations of mandibular discrepancies, 3 by retrusion and 3 by protusion from each original face. The 28 faces were evaluated by orthodontists, maxillofacial surgeons, artists, and laypersons. RESULTS: The greatest numbers of indications for surgery were made for male convex profiles and for female concave profiles. Laypersons were more tolerant to profile changes, whereas maxillofacial surgeons indicated surgery and stated that they would seek facial surgery if profiles were their own in a greater number of cases. CONCLUSION: The angle of facial convexity has a strong effect on the perceived need for orthognathic surgery.

Comparison of mandibular rami width in patients with prognathism and retrognathia.

PURPOSE: The purpose of this study was to assess the ramus thickness in skeletal Class III and Class II patients. METHODS: Forty patients were evaluated using computed tomography scanning. RESULTS: Compared with the Class II patients, the mandibular ramus of Class III patients was thinner. The ramus thickness in retrognathic patients was 8.84 mm and the ramus thickness in prognathic patients was 7.80 mm. CONCLUSION: The ramus is thinner in patients with prognathism than in those with retrognathia.

[Laser therapy in orthognatic surgery]. / Láserterapia en cirugía ortognática.

This study describes the prevalence of patients with dentofacial deformities attended in the Maxillofacial Surgery Department of Hospital de Especialidades del Centro Medico Nacional Siglo XXI of the IMSS, during January to December 2002. Twenty-six patients received postoperative laser therapy in the right area of the mandible ramus, after bilateral sagittal modified osteotomy (BSMKSO). The results with laser therapy showed less pain and edema in comparison other patients without this therapy. The results were carried out after 24 hours, 3 days, 8 days and 15 days, and after 10 treatments of laser therapy. The X-Ray and biopsy showed bone healing 30 days, six and eight weeks after orthognatic surgery procedures.

Láserterapia en cirugía ortognática / Laser Therapy in Orthognatic Surgery

Se describen losresultados de un estudio clínico observacional sobre laserterapia en la fase postoperatoria de 26 pacientes sometidos a reducción de prognatismo mandibular con osteotomía sagital bilateral de rama ascendente (OSBMKS). Todos los procedimientos de cirugía ortognática fueron realizados de enero a diciembre de 2002, en el Servicio de Cirugía Maxilofacial del CMN SXXI del IMSS aplicando en el lado derecho de la región intervenida hasta 10 sesiones de láser diódico, siendo el izquierdo el lado control, observando mejoría en disminución del dolor y del cuadro inflamatorio agudo en relación a los pacientes a quienes no se aplicó esta terapia. Se evaluaron los resultados con medición clínica del edema postoperatorio a las 24 horas, 72 horas, 8 días, 15 días y se verificaron los cambios histológicos y radiográficos ocurridos en el proceso de cicatrización ósea a los 30 días, 6 y 8 semanas posterior a la cirugía ortognática.

This study describes the prevalence of patients with dentofacial deformities attended in the Maxillofacial Surgery Department of Hospital de Especialidades del Centro Médico Nacional Siglo XXI of the IMSS, during January to December 2002. Twenty-six patients received postoperative laser therapy in the right area of the mandible ramus, after bilateral sagittal modified osteotomy (BSMKSO). The results with laser therapy showed less pain and edema in comparison other patients without this therapy. The results were carried out after 24 hours, 3 days, 8 days and 15 days, and after 10 treatments of laser therapy. The X-Ray and biopsy showed bone healing 30 days, six and eight weeks after orthognatic surgery procedures.

[Facial prognathism and its relation to the cranial base in Brazilian children with Class I malocclusion]. / Prognatismo facial e sua relaçao com a base do crânio em crianças Brasileiras portadoras de má-oclusões Classe I.

The objective of this work was to study the degree of the facial prognathism, considering the relationships between the SNA and SNB angles with the saddle angle (NSAr and NSBa). The sample consisted of eighty cephalometric roentgenograms, taken in lateral norm, of Brazilian white children, forty boys and forty girls, with both dental and skeletal, class I malocclusions, with ages between 9 years and 2 months old and 13 years and 7 months old. Data were statistically analysed and the sample was divided in three groups considering the mean value and the standard deviation of the NSAr angle. Sixteen subjects (seven boys and nine girls, 20 percent of the sample) presented an NSAr angle that was smaller than 119.5 degrees (x - 1s); twenty subjects (forteen boys and six girls, 25 percent of the sample), showed an NSAr angle more than 127.5 degrees (x + 1s) and forty-four subjects (nineteen boys and twenty-five girls, 55 percent of the sample) had an NSAr angle value between 119.5 and 127.5 degrees (x +/- 1s). The results led to the following conclusions: 1. There is a negative correlation, statistically significant between the saddle angle (NSAr and NSBa) with the SNA angle in subjects with class I malocclusions. An NSAr or NSBa angle higher than the mean value plus one standard deviation, it is associated with of the maxilla retrognathism and contrariwise. 2. There is a negative correlation, statistically significant between the sadle angle (NSAr and NSBa) with the SNB angle in subjects with malocclusions. An NSAr or NSBa angle higher than the mean value plus one standard deviation, it is associated with the mandible retrognathism and contrariwise. 3. The normal values of the SNA and SNB angles for an individual and the degree of the facial prognathism should be determined individually, since that the values of these angles might be affected for cranial base morphology.

The craniofacial pattern of the Lengua Indians of Paraguay.

Lateral cephalometric headfilms of 30 male and 30 female Lengua Indians taken in the Chaco area of Paraguay were compared with a sample of 23 male and 25 female South African Caucasoids with excellent occlusion. The most obvious difference noted between the two population groups was the degree of prognathism evident in the Lengua. This was attributed to the generally shorter anterior cranial base in the latter group rather than to the size or forward positioning of their jaws. The significantly larger ANB (Subspinale, Nasion, Supramentale) angle observed in the Lengua was attributed to one or both of two factors, namely, the short anterior cranial base or the clockwise rotation (forward tipping) of the jaws relative to the anterior cranial base. Chinpoint position relative to the anterior cranial base in the Lengua is not much different from that of our Caucasoid sample. The lower incisor teeth in the Lengua, but not the upper ones, are more labially inclined than those of the Caucasoids.