Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PROGNATHISM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2005

Bilateral sagittal split osteotomy for correction of mandibular prognathism: long-term results.

PURPOSE: To identify the long-term maxillomandibular changes after surgical correction of mandibular prognathism using bilateral sagittal split osteotomy (BSSO). PATIENTS AND METHODS: Twenty patients who underwent BSSO to setback the mandible and had cephalometric radiographs taken preoperatively and postoperatively at 6 weeks, 1 year, and long-term follow-up (mean, 28 months). The cephalograms were traced and measured to determine the operative and postoperative changes. Correlation analyses were performed to see the relationship between the magnitude of setback and the amount of long-term postsurgical change at B point and pogonion. RESULTS: The mean surgical setback was 8.2 mm at B point and 8.8 mm at pogonion. The mean long-term horizontal relapse was 2.3 mm (28.0%) at B point and 3.0 mm (34.1%) at pogonion. Out of 20 patients, 12 (60.0%) relapsed horizontally greater than 2 mm at B point and 13 (65.0%) at pogonion. The mean vertical surgical changes showed downward displacement of B point (2.3 mm) and pogonion (2.0 mm). The mean long-term vertical relapse was 1.6 mm (69.6%) at B point and 1.7 mm (85.0%) at pogonion. CONCLUSION: There was no correlation between the magnitude of setback and the amount of relapse at B point and pogonion. However, there was significant correlation between the magnitude of vertical, downward surgical displacement and the amount of vertical relapse at B point and pogonion. The majority of the maxillofacial changes occurred within 1 year postoperatively.

Adolescent↗
PubMed2004

3D CT evaluation of masseter muscle morphology after setback osteotomy for mandibular prognathism.

OBJECTIVE: Following mandibular setback osteotomy, changes in the direction, length, and cross-sectional area of the masseter muscle were studied by means of computerized tomography (CT) images generated with a 3-dimensional (3D) reconstructive technique. STUDY DESIGN: Pre- and postoperative CT examinations were performed on 17 prognathic patients treated by sagittal split ramus osteotomy with rigid osteosynthesis and 13 patients treated by intraoral vertical ramus osteotomy without osteosynthesis. The pre- and postoperative masseter muscle direction and length were evaluated using 3D CT images observed from a lateral viewing angle. The cross-sectional area of the masseter muscle was first measured on an axial CT image of a selected slice level, following which the right-angle cross-sectional area of the muscle was revised using the measured area from the axial image. RESULTS: Postoperatively, anterior tilting of the masseter muscle was observed; however, masseter muscle length was unchanged. Three months postoperatively, a significant reduction in the cross-sectional area of the masseter muscle was seen. A tendency to revert back to the normal dimension was seen between 6 months and 1 year postoperatively. No significant difference was noted between the 2 surgical techniques. CONCLUSIONS: Three-dimensional computed tomography is an adequate imaging modality for masseter muscle evaluation. The results of this study suggest the masseter muscle may undergo reversible atrophy after mandibular setback osteotomy.

Adolescent↗
PubMed1993

Masticatory function in patients with mandibular prognathism before and after orthognathic surgery.

Masticatory function was analyzed in 54 patients with mandibular prognathism before or after orthognathic treatment and in 40 adults with normal occlusion. Masticatory efficiency was evaluated spectrophotometrically by measuring the amount of adenosine triphosphate eluted from masticated adenosine triphosphate granules. Occlusal contact was evaluated by calculating the number and area of occlusal contacts from the illuminated images of a silicone record of the occlusion that was stored in the image analysis system with the aid of a charge-coupled device camera. The mean masticatory efficiency of the preoperative group was approximately half that of the control group. The value for the postoperative group was slightly higher than that for the preoperative group, but there was no statistical difference between the two groups. Likewise, the number and area of occlusal contacts in the preoperative group were also approximately half or less as compared with those of the control group, and they did not show significant changes postoperatively. Statistically, there were correlations between the masticatory efficiency and the number and area of occlusal contacts. The results indicate that although the occlusal relationship of the upper and lower teeth were greatly improved by orthognathic treatment, the postoperative occlusion is not tight enough and may need further adjustment at the end of the treatment.

Adenosine Triphosphate↗
PubMed1997

Stability after surgical correction of mandibular prognathism using the sagittal split ramus osteotomy and fixation with poly-L-lactic acid (PLLA) screws.

PURPOSE: This study was designed to examine skeletal stability after surgical correction of mandibular prognathism using a sagittal split ramus osteotomy (SSRO) and fixation with poly-L-lactic acid (PLLA) screws. PATIENTS AND METHODS: Twenty patients with Class III malocclusion were treated with bilateral SSRO and mandibular setback. Ten underwent fixation with titanium screws (group I) and the other 10 with PLLA screws (group II). Cephalograms were obtained 2 or 3 days postoperatively, and at 3, 6, and 12 months after the operation. Changes in the position of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms. RESULTS: Certain tendencies for overjet and overbite were noted to have decreased more markedly, and changes in the position of the skeletal points were greater in group II than in group I. However, statistical analysis showed no significant differences between the two groups. CONCLUSION: Our results suggest that fixation of the bony segments with PLLA screws after SSRO may be used effectively in properly selected cases.

Adolescent↗
PubMed1977

Periapical condition of anterior teeth after surgical correction of mandibular prognathism. A radiographic study.

Extrusion and root resorption of the mandibular anterior teeth have been reported after surgical correction of mandibular prognathism by horizontal osteotomy of the rami. The aim of the present study was to find out whether oblique sliding osteotomy also has such side effects. Intraoral radiographs of the maxillary and mandibular anterior teeth of 61 patients were studied. Enlargement of the periodontal space and signs of root resorption were estimated postoperatively and at a later review 1 1/2-5 years after the operation. Enlargement of periodontal space occurred postoperatively in 16.2% of the maxillary incisors and 52.2% of the mandibular incisors. The enlargements were mostly reversible and at the final review only 1.1 and 8.5% of the maxillary and mandibular incisors, respectively, showed such enlargements. Root resorption was rarely found in radiographs from the postoperative control. At the final review, however, there were signs of root resorption of 1.6 and 20.8% of the maxillary and mandibular incisors, respectively. It appears warranted to conclude that the anterior teeth, especially the mandibular incisors, are exposed to strong forces also after oblique sliding osteotomy of the mandibular rami.

Adolescent↗
PubMed1978

Giant ranula causing mandibular prognathism.

This is a case report of a 20-year-old man with ranula, the size of an orange, in the floor of the mouth causing mandibular prognathism with fan-shaped mandibular teeth anterior to the premolars. The tumor was extirpated. The pathogenesis, differential diagnosis and treatment of ranulas are discussed.

Adult↗
PubMed1981

Changes of lateral soft tissue profile after surgical correction of mandibular prognathism.

The lateral soft tissue profile was recorded in 10 patients with slight to moderate degrees of mandibular prognathism, preoperatively, and 6 weeks after subcondylar sliding osteotomy had been performed. The recording method was mechanical. Only small and insignificant profile changes were found in the submandibular and occlusal plane regions as well as in the ramus region. The only significant change of profile was found in the mandibular body region, probably as a result of firm connection between soft tissue and underlying distally moved bone. The lack of significant profile change in the osteotomy region was in accordance with subjective observations and was probably due to local remodelling and adaptation processes. The facial width was thus found to be unaltered 6 weeks postoperatively.

Adult↗
PubMed1981

Sagittal chin rotation of the prognathic edentulous mandible.

In edentulous patients with a prognathic mandible, a pronounced chin and extensive resorption of the lower alveolar ridge, the commonly used techniques of ramus osteotomy and chin reduction will not give optimal results in the majority of cases. The solution of this problem can be obtained by mandibular body ostectomy and a sagittal rotation of the frontal part of the lower jaw. By this operation the originally horizontally orientated upper plane of the chin area is placed in a more vertical position. This operative technique gives a better predictable facial contour than the conventional methods. It causes no unfavorable displacement of the lower lip and, which is very important, it gives an absolute increase of height of the lower alveolar ridge and a more favorable inclination of the frontal part of the alveolar process from a prosthetic point of view. The problems encountered and the results obtained by this technique will be demonstrated by a short case presentation.

Adult↗
PubMed1980

The influence of prognathism surgery on the width and the length of the lower third of the face.

The width and the length of the face in frontal view as important factors in facial harmony are analysed. Two groups of patients with mandibular prognathism were photographed, analysed and evaluated. The lower third of the face generally becomes shorter after a sagittal splitting operation as well as after a sagittal splitting plus additional medial ostectomy of the lower incisor region. In both groups we did not find a significant change in the width of the face. The impression of broadening the face by the sagittal splitting method is therefore subjective. In both groups, the face became more harmonious indimension following the osteotomies.

Cephalometry↗
PubMed1987

Extraoral and intraoral vertical subcondylar ramusosteotomy for correction of mandibular prognathism.

Vertical subcondylar ramusosteotomy for correction of mandibular prognathism was performed in 203 cases with an extraoral (EVSO) and in 55 cases with an intraoral (IVSO) approach. Clinical and surgical observations were analyzed and the 2 techniques compared with regard to operation time, per- and postoperative complications, postoperative morbidity of the patients and the duration of hospital stay. The extraoral approach demonstrated significantly shorter operation time, less blood loss and shorter hospital stay. The extent of postoperative swelling, nausea and vomiting was also in favour of the EVSO. Serious complications were few, and both techniques were considered as satisfactory and safe.

Adolescent↗
PubMed1988

Stability after vertical subcondylar ramus osteotomy for correction of mandibular prognathism.

A cephalometric analysis of the positional changes of the mandible and the upper and lower incisors following vertical subcondylar ramus osteotomy was performed on 80 patients. The patients were prognathic without laterognathism or open bite and all the patients had preoperative orthodontic treatment. 40 patients were operated with an intraoral (IVSO) and 40 with an extraoral approach (EVSO). Both groups showed postoperatively posterior rotation of the mandible, shortening of the posterior facial height, increase in anterior facial height and extrusion of the incisors in both jaws. A significantly greater reduction of posterior facial height was observed in the EVSO-group, but otherwise the 2 groups did not reveal any statistically significant positional differences. The material was sub-divided into 2 groups 1 with (n = 32) and one group without (n = 48) extra skeletal (nasomandibular) fixation in addition to the intermaxillary fixation. Significantly less positional changes of the incisors and less increase of anterior facial height was found in the group with skeletal fixation, but the influence on other skeletal alterations was limited. After release of the intermaxillary fixation, the only difference between the groups was intrusion of the earlier extruded incisors, most pronounced in the group without skeletal fixation.

Adolescent↗
PubMed1988

Surgical treatment of the open bite deformity. Surgical correction of combined mandibular prognathism and open bite by oblique sliding osteotomy of the mandibular rami.

Treatment of open bite deformity combined with a prognathic mandible using the oblique, sliding osteotomy of the mandibular rami has been followed for 2 1/2 years to evaluate the final outcome of the operation. The clinical and radiographic examination during the control period show a remarkably stable result with a relapse magnitude the same or slightly less than that for a straight, set-back procedure. A certain dental compensation occurs during the skeletal relapse. The thought of creating a certain "freedom-space" in the muscular fibres during the set-back procedure, thus facilitating closure of the open bite is proposed. Surgical correction of the anterior open bite today is otherwise most frequently focused on solutions with maxillary le Fort I or subapical procedures to ensure minimal influence from the jaw muscles.

Cephalometry↗
PubMed1991

Extraoral subcondylar ramus osteotomy for correction of mandibular prognathism. The surgical technique and complications.

1178 patients with mandibular prognathism and/or asymmetry, in some cases combined with maxillary retrognathism, were treated by extraoral horizontal or oblique ramus osteotomy during the period from 1939 to 1989. The described percutaneous retromandibular approach is a simple, rapid and reliable technique which can usually be performed under local anaesthesia. Very few complications, particularly neurological, were observed. These aspects justify consideration of this technique when indications for a simple, straight set-back procedure of the mandible exist, and there is no tendency to bite-opening. However, the method demands intermaxillary fixation for 6-9 weeks postoperatively.

Adolescent↗
PubMed1990

Factors contributing to skeletal relapse after surgical correlation of mandibular prognathism.

Postoperative follow-up and multiple regression analysis of skeletal relapse following mandibular setback were carried out to clarify the timing and causes of the relapse. The subjects were 24 mandibular prognathism patients. All patients underwent intraoral oblique sagittal splitting osteotomy with circumferential wiring and intermaxillary fixation for 8 weeks. Occlusal splints were not used. Postoperative positional changes of segments were evaluated by lateral cephalograms taken at appropriate intervals. Horizontal relapse was most evident within six months after surgery; vertical relapse seldom occurred. Multiple regression analysis revealed little association between preoperative morphological patterns and postoperative relapse. Although spatial changes of the proximal segment at operation and age of the patient were the best predictors for postoperative horizontal relapse, analysis indicated unsatisfactory prediction of vertical relapse because of its rare occurrence. Based on these results, the aetiology of relapse is discussed and two proposals are suggested for its prevention.

Adolescent↗
PubMed2000

Three-dimensional computed tomographic evaluation of morphologic airway changes after mandibular setback osteotomy for prognathism.

OBJECTIVE: To observe changes in the pharyngeal airway and the hyoid bone position after mandibular setback osteotomy in 30 patients with mandibular prognathism by means of 3-dimensional computed tomography (3DCT). STUDY DESIGN: Preoperative and postoperative computed tomography (CT) examinations were performed on 17 patients treated by sagittal split ramus osteotomy with rigid osteosynthesis and on 13 patients treated by intraoral vertical ramus osteotomy without osteosynthesis. The amount of mandibular setback was measured by the preoperative to postoperative difference of the mandibular position in axial CT images. The sizes of the preoperative and postoperative pharyngeal airway were evaluated from semitransparent and crosscut 3DCT images. Postoperative displacement of the hyoid bone was evaluated by a technique to superimpose a postoperative hard tissue 3DCT image on the preoperative image. The helical scan technique was used in the CT examination. The volume rendering technique was used to create 3DCT images. RESULTS: The mean mandibular setback was 7.8 +/- 2.1 mm with a range of 5 to 11 mm. Three months after surgery, the lateral and frontal widths of the pharyngeal airway had decreased significantly in comparison with the preoperative width. The mean reduction rates of the lateral and frontal width were 23.6% and 11.4%, respectively. The diminished airway did not recover by either 6 months or 1 year after surgery in most cases. Downward and posterior displacement of the hyoid bone was seen postoperatively. There were positive correlations between the amount of mandibular setback and reduction of the lateral width of the pharyngeal airway (r = 0.54) and the amount of hyoid bone displacement (r = 0.42). There were no significant differences between the two surgical techniques. CONCLUSION: Three-dimensional computed tomography was a practical imaging technique to evaluate the morphologic airway changes. The pharyngeal airway may have irreversible narrowing after mandibular setback surgery.

Adolescent↗
PubMed1978

Hyoid changes following orthopedic treatment of mandibular prognathism.

In this study 30 patients exhibiting mandibular prognathism were treated by the orthopedic chin-cup appliance for a three-year period. The patients began treatment at the age of six years and completed treatment at the age of nine years. As previously reported, chin-cup treatment resulted in a "clockwise" facial rotation with the mandible moving relatively posteriorly and inferiorly. Hyoid position measured in this study also tended to move slightly posteriorly but was primarily displaced in an inferior direction. The positional alteration exceeded in amount what might have been expected by growth alone. The inferior direction of change in hyoid and associated structures and the resultant lack of encroachment on the vital pharyngeal passageways suggests that stability and patency of the pharyngeal airway is a primary factor in hyoid positioning. The duration and "growth guidance" aspects of treatment allowed for functional as well as morphologic adaption to the altered hyoid position.

Cephalometry↗
PubMed1990

Stability of mandibular incisors following excessive proclination: a study in adults with surgically treated mandibular prognathism.

The purpose of this study was to determine if mandibular incisors could be proclined markedly without increasing the potential for relapse of crowding. Patients with surgically treated mandibular prognathism were selected. In 29 patients the mandibular incisors were proclined more than 10 degrees during the presurgical orthodontic phase. The remaining 33 patients had only minimal change in incisor inclination. A long-term follow-up examination was performed 10.0 (SD 2.3) and 11.1 (SD 3.1) years postoperatively in 26 and 24 patients, respectively. Study casts were measured before and after treatment, three years after surgery, and long-term. Cephalograms were evaluated before and after treatment, immediately before and after surgery, and three years after surgery. Prior to therapy the patients treated with presurgical proclination had less dental arch length and more retroclined and crowded mandibular incisors than the patients in the other group. No differences in parameters were observed at later intervals. Dental arch length and intercanine width decreased and incisor irregularity increased in both groups during the follow-up periods. No intergroup differences in changes were observed. Indications for proclination of mandibular incisors are discussed.

Adult↗