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PubMed1991

Maxillary advancement for mandibular prognathism: indications and rationale.

The surgical correction of mandibular prognathism has traditionally involved posterior repositioning of the mandibular body. This treatment approach corrects the skeletal disproportion at the expense of reducing facial skeletal volume and can unpredictably result in inadequately supported soft tissues with loss of skeletal definition. In an effort to avoid these sequelae of mandibular reduction, 18 patients diagnosed as having mandibular prognathism were treated with maxillary advancement surgery at the Le Fort I level. Mean patient SNB angle was 85.2 degrees, as compared with a normal 79 +/- 3 degrees. Maxillae were documented to be in normal position relative to both cranial base and Frankfort horizontal. The mean maxillary advancement was 6.9 mm, with a range of 4.5 to 8.8 mm. All patients required genioplasty to reduce vertical chin height and/or to laterally shift the chin. At the time of follow-up (mean 16.2 months), all patients retained cephalometric data suggestive of enlarged mandibles and excessive anterior facial divergence. However, maxillomandibular harmony and facial convexity had been restored without sacrificing skeletal volume. Treatment results demonstrated these faces to be skeletally well proportioned despite lower face protrusion that was beyond "normal." Postoperative appearances were characterized by a well-supported soft-tissue envelope and a highlighted skeletal foundation, creating angular, well-defined lower faces. These findings support the credibility of maxillary advancement as the procedure of choice in selected individuals with mandibular prognathism. Indications and an aesthetic rationale for this surgical approach are presented.

Adolescent↗
PubMed1998

Mandibular stability after sagittal split ramus osteotomy without post-operative maxillomandibular fixation in the treatment of prognathic patients with symmetric mandibles.

This study was designed to examine post-operative stability in prognathic patients with symmetric lower jaws who underwent sagittal split ramus osteotomy (SSRO) of the mandible without post-operative maxillomandibular fixation (MMF). Twenty prognathic patients with symmetric mandibles were investigated. An appliance for repositioning the proximal segment and titanium screw fixation was applied in all patients. Ten patients underwent post-operative MMF with stainless steel wire (mean duration, 9.6 days) and intermaxillary rubber traction after removal of the MMF (Group I), and the remaining ten underwent intermaxillary rubber traction only (Group II) post-operatively. Cephalograms were obtained 2-3 days post-operatively, and 3, 6, and 12 months after surgery. Changes in the positions of upper incisors (U-1), lower incisors (L-1), B-point, and pogonion were examined on lateral cephalograms. In the early stages of follow-up, decreases in the overbite tended to be more marked in Group I than in Group II, and the forward movement of each standard point was significantly larger in Group I than in Group II. No significant differences, however, were revealed between the two groups at 12 months after surgery. Forward movement of anterior cephalometric landmarks, post-operatively, in Group II were significant, however, this pattern differed from Group I, in which big changes occurred in the early stages after surgery. Although the patterns of post-operative changes in the two groups are different, there are no significant differences in their post-operative stability in long-term follow-up. Therefore, post-operative MMF may be avoided when prognathic patients with symmetric mandibles undergo SSRO with an appliance for repositioning the proximal segment and titanium screw fixation.

Adult↗
PubMed1992

Disfigurement and psychosocial handicap of adults with extreme mandibular prognathism.

Questionnaires and psychological tests were used to assess the psychosocial impact of mandibular prognathism. Patients with mandibular prognathism were asked to assess the impediments caused by their dentofacial deformity. In addition, they were asked to rate their appearance and to report the effect that it had on their social contacts. The self-assessment revealed that patients felt esthetically impaired, but that they had a fairly positive autostereotype, as revealed by their self-descriptive choices on a personality scale. These results were compared with the assessments made by two different control groups composed of persons with no esthetic impairment. The attitudes of the control groups toward the patients were more negative than perceived by the patients, indicating that mandibular prognathism does result in a social handicap.

Adolescent↗
PubMed1992

[Psychology and recurrence tendency in relation to age at operation for prognathism].

Within this study patients with mandibular prognathism were studied as to their psychological situation pre- and postoperatively with the help of the Freiburg Personality Evaluation Sheet. Since it was our special interest, whether psychologically it makes a big difference whether the patients were operated during the time of adolescence or after the age of twenty, the postoperative investigation was carried out with special reference to this point. Without any doubt, the correction of prognathism improved the psychological situation of the patients. It was obvious that for those patients in between fourteen and seventeen the improvement was more helpful than for those patients after the age of twenty. On the other hand the rate of recurrence was much higher within the group of those patients operated in between fourteen and seventeen (29.8%) than for those patients which were operated later than at age twenty (8%). The ideal age for the correction of mandibular prognathism must be found individually. While the operation at an early time is more helpful for the psychological situation of the patients, it must on the other hand be seen that for this age-group the danger of recurrence is higher.

Adolescent↗
PubMed2003

[The long term stability after orthognathic surgery in prognathic patients with mandibular asymmetry].

OBJECTIVE: This study was conducted to evaluate the skeletal stability after mandibular osteotomy, the effect of the two-fixation method used (unilateral plate versus bilateral plates), the influence of condylar bony change, and the relationship between the magnitude of setback and the relapse. METHODS: Twenty-three patients who have mandibular prognathism with asymmetry were selected from a pool of orthodontic patients at the Department of Orthodontics, Niigata University Dental Hospital. To evaluate the stability after surgery, the lateral and frontal cephalograms taken just before surgery (T1), just after surgery (T2), and retention time (long term postoperatively, >6 months) (T3) were used. RESULTS: In general, the long-term post-operative stability term was satisfied. TMJ symptom was relieved after surgery. The The long-term relapse tendency was larger in those patients who had pre-operative condylar bony change. From our data, there was no significant difference about the long-term change due to post-operative skeletal relapse between bilateral SSRO cases and USSRO+IVRO cases. There was no correlation between the magnitude of setback and the long-term post-operative relapse. CONCLUSION: It was suggested that even if condylar bony change existed before surgery, the patient could receive mandibular osteotomy and enjoy a good post-operative stability. Condylar bony change might be one of the risk factors for the stability after mandibular osteotomy in prognathic patients with mandibular asymmetry. The type of mandibular osteotomy, the fixation of mandibular and the amount of setback might have no relationship with the postoperative relapse in prognathism with mandibular deviation.

Adolescent↗
PubMed1989

[Anterior body ostectomy for mandibular prognathism].

The mandibular body ostectomy is indicated for the correction of select cases of; Mandibular prognathism, Class III open-bite deformity, Anterior crossbite in the adult. The anterior body ostectomy is indicated primarily in selected cases of mandibular prognathism, class III malocclusion when the posterior teeth are not in crossbite or the crossbite is dental in nature and can readily be resolved with conventional orthodontics. As with the correction of other dentofacial deformities, carefully done model surgery and a cephalometric prediction tracing are imperative in planning the anterior body ostectomy. In this paper, a case of mandibular prognathism which is corrected by the technique of anterior body ostectomy is presented.

Adult↗
PubMed2005

[Pre- and post-surgical orthodontic treatment of mandibular asymmetry and prognathism].

OBJECTIVE: The purpose of this study was to analyze the pre- and post surgical orthodontic treatment of mandibular asymmetry and prognathism in our hospital, and to summarize some helpful experiences for future clinical work. METHODS: The data were derived from 21 adults aged from 19 - 28 years who had severe mandibular asymmetry and prognathism. The ANB angle of all patients is from -3 degrees to -8 degrees. The value of wits of all patients is from -7 mm to -14 mm. The deviation of chin point of all patients is from 3 mm to 7 mm. RESULTS: The duration of pre- and post-surgical orthodontic treatment was 10-20 months (mean 18 months) and 5-10 months (mean 7.5 months), respectively. The keys in pre-surgical orthodontic treatment include (1) three dimensional dental decompensation; (2) arch form and transverse discrepancy correction; (3) model surgery and the splint making. The main objective of post surgical orthodontic treatment is to detail the occlusion. CONCLUSIONS: Pre- and post surgical orthodontic treatment is essential for the orthognathic treatment of patients with mandibular asymmetry and prognathism.

Adult↗
PubMed1994

Surgical treatment of mandibular prognathism in collaboration with orthodontic treatment in Korea.

Mandibular prognathism is defined by John Hunter as follows: "The lower jaw projecting too far forward so that the foreteeth pass before those of the upper jaw, therefore disfigurement and malocclusion are two of the main facial characteristics." Other distinguishing features are the coexistence of class III malocclusion, incomplete closure of lip, deviation of the midline, and decrease of labiomental fold. Generally, the functional occlusal relationship and balanced facial harmony cannot be obtained by surgical or orthodontic treatment alone. Its success depends on careful conjoint, supplementary diagnostic, and treatment planning. As a cardinal principle the authors made the following combined surgical and orthodontic treatment plans: (1) Orthodontic treatment relocates and decompensates the malpositioned teeth (remove the masking effect of teeth) and, therefore, skeletal deformity is exposed maximally. (2) Surgical treatment eliminates the maximally exposed skeletal defect. Therefore, dramatic facial balance and functional occlusal relationship are obtained. Treatment planning includes the pre- and postoperative orthodontic treatment, lateral cephalometric prediction tracing (LCPT), and model surgery with dental cast. The authors made it easy with the use of an acrylic dental wafer to coordinate exact occlusal relationship after surgery. We treated mandibular prognathism by using Dautrey's modification of the sagittal split ramus osteotomy (SSRO) (10 cases) and intraoral vertical ramus osteotomy (IVRO) (5 cases) and sometimes additional genioplasty (2 cases). IVRO was used in those cases where (1) the amount of setback was more than 10 mm and (2) where there was a flat gonial angle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1978

Soft-tissue changes related to the surgical management of mandibular prognathism.

A series of fifty patients treated surgically for mandibular prognathism has been analyzed statistically to study relative soft- and hard-tissue changes. Changes in the soft tissue of the chin and in the lower lip position relative to the underlying mandibular structures are well related in a nearly 1:1 ratio. Upper lip modifications have been shown to be less well related to mandibular repositioning. The ratio of change of mandibular landmarks to soft-tissue points and their over-all positional change can be helpful in presurgical treatment planning of patients with mandibular prognathism.

Cephalometry↗
PubMed1981

Prepubertal growth of mandibular prognathism.

This study deals with an analysis of the growth changes of the face associated with mandibular prognathism during a period before puberty. The investigation was based on two groups of Japanese girls--an experimental group of eighteen girls and a control group of twenty-two. Each set of serial lateral cephalometric roentgenograms consisted of a 4-year series from the ages of 7 to 10 years. Analysis was done on the annual size attainment of several facial components of the two groups. The results indicate that growth in cases of mandibular prognathism showed an incremental change similar to that of the normal group before the pubertal period.

Cephalometry↗
PubMed1982

Mandibular prognathism: a cineradiographic analysis of mandibular and hyoid bone movements before and after surgical correction.

A study was undertaken to investigate the effect of surgical treatment of mandibular prognathism on mandibular and hyoid movements during speech and swallowing in fourteen individuals. The material consisted of cineradiographic records of adult prognathic patients before and after the surgical correction. The records were obtained with a 16 mm, cinecamera at a speed of thirty-two frames per second. Image intensification was used, and the head of the patient was positioned in a cephalostat during the recording. Postoperative recordings were taken at about 1 month after the removal of intermaxillary fixation. To improve the accuracy of the analysis, templates of the skeletal structures were prepared. The following cephalometric landmarks were located and marked on the template: the tip of the upper central incisor, the occlusal plane, pogonion, and hyoid point. The coordinates of the cephalometric points were recorded by means of a Lysta dental digitizer linked to a Hewlett-Packard 9815A desk-top computer. The significance of the difference between the pre- and postoperative values was determined by the Student's test. The results were examined for variations in the vertical and horizontal ranges of movement and in the surface areas covered by pogonion and hyoid during movement. Correlation between several pairs of variants was tested. Large individual variations were found in the pattern and range of movement of the mandible and hyoid both pre- and postoperatively. The coefficients of correlation between several parameters showed some significant correlation, which disappeared after surgical correction. A general trend for a reduction in most parameters studied was shown. Some correlation between the amount of setback and the mandibular movement was also found. The hyoid and mandibular movements in tongue-reduction cases do not differ significantly. Lines of further investigation are suggested, with larger and possible more homogeneous samples.

Cineradiography↗
PubMed1983

Surgical correction of mandibular prognathism with a functionally stable osteosynthesis of the mandibular body.

Several methods have been described for the surgical correction of mandibular prognathism. Current techniques favour surgical correction at the site of the anomaly itself and in the case of skeletal mandibular prognathism it is the mandibular body that must be cut and shortened. The authors describe two methods of oblique ostectomy and of sagittal splitting with ostectomy of the mandibular body, by which a planned and measured reduction of the size of the mandible can be achieved. The techniques provide a functionally stable osteosynthesis, the optimum conditions for post-operative bone healing and so reduce the period of intermaxillary immobilisation. The special problems of articular derangements of the temporo-mandibular joint due to a stable osteosynthesis can be avoided by the combined use of zygomatico-mandibular positioners and occlusal splints.

Female↗
PubMed1978

Correction of prognathism with fixed and removable partial dentures.

Prognathism in those patients for whom surgical orthodontic procedures are contraindicated can be successfully treated by the use of fixed and removable partial denture prosthodontics. Careful neuromuscular evaluation of the patient is necessary for the success of the treatment rendered. The nonsurgical treatment of prognathism by this method was described.

Acrylic Resins↗
PubMed1976

Surgical correction of mandibular prognathism.

Procedures used in the correction of certain forms of mandibular prognathism are described. All but one of these techniques allow an immediate functional healing, which is considered to be most important. Since no single procedure can correct all the different forms of mandibular prognathism, each case is individually planned and a "custom-tailored" technique is applied.

Alveolar Process↗
PubMed1991

Alterations of hyoid bone position and pharyngeal depth and their relationship after surgical correction of mandibular prognathism.

The present investigation studied changes of hyoid bone position and pharyngeal depth at the levels of the second and fourth cervical vertebrae and their relationships in mandibular prognathism patients who received combined orthodontic-surgical treatment. The material consisted of presurgical and 1-year postsurgical profile cephalograms of 52 adult orthognathic surgery patients (40 females and 12 males) who initially had mandibular prognathism and had undergone bilateral vertical ramus osteotomy through an extraoral incision in the retroangular area. Hyoid bone position and pharyngeal depth were assessed on the profile radiographs with 10 cephalometric variables. Paired t tests were used to evaluate the operative changes in all cephalometric parameters. The relationships between pairs of variables describing hyoid bone position and pharyngeal depth were assessed by means of Pearson's product-moment correlation analysis. Significant differences (p less than 0.01) were observed for the distances of the hyoid bone to the maxilla and the mandible. The distances of the hyoid bone with the anterior cranial base, the vertebral column, and the anterior pharyngeal wall, and the measurements representing pharyngeal depth exhibited no significant changes (p greater than 0.05). Moderate correlations were seen between (1) the depth of the pharynx at the fourth cervical vertebra and the hyosymphyseal distance (r = 0.34) and the distance between the point of the projection of the hyoid bone to the mandibular line with its posterior border (r = -0.34), and (2) the depth of the pharynx at the second cervical vertebra and the distance of the hyoid bone with the anterior pharyngeal wall at the level of the fourth cervical vertebra (r = -0.33).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2006

Mandibular remodeling after bilateral sagittal split osteotomy for prognathism of the mandible.

PURPOSE: To describe the postoperative remodeling changes in the mandible after bilateral sagittal split osteotomy to correct mandibular prognathism. PATIENTS AND METHODS: Twenty patients who underwent bilateral sagittal split osteotomy for the correction of mandibular prognathism were studied for postoperative remodeling changes within the mandible. The 6-week, 1-year, and long-term postoperative cephalometric mandibular tracings of 12 patients were superimposed using the fixation wires as the stable reference points to demonstrate the specific locations of the intrabony remodeling. RESULTS: There was a general direction of remodeling at the condylion and gonion anteriorly and superiorly, while the B point and pogonion did not show much change in remodeling. At the condylion, 60% and 40% of the cases showed significant horizontal and vertical remodeling, respectively. At the gonion, 50% and 55% of the cases showed significant horizontal and vertical remodeling, respectively. No correlation was found between the remodeling changes at condylion and gonion and the surgical movement or relapse at B point and pogonion. There was a significant correlation between the observed horizontal relapse at gonion and the horizontal remodeling changes at this point showing that the postoperative displacement of this point is a result of both positional translocation and remodeling changes. CONCLUSION: The results of this study show that there are intrabony remodeling changes that occur in the mandible after sagittal split osteotomy and that these continue for a long period of time in some patients. This remodeling occurred more in the condylar and gonial areas, while the chin remained relatively stable.

Adolescent↗
PubMed2006

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.

Adolescent↗
PubMed1981

Correction of mandibular prognathism by mandibular setback and advancement genioplasty.

The goal of surgical-orthodontic treatment of mandibular prognathism is to achieve maximum function, esthetics and stability. These objectives were achieved in 10 adults who manifested a specific type of mandibular prognathism. The patient group under study, who manifested a relatively contour deficient chin and prominent lower lip, and class III malocclusion, was treated by orthodontics and mandibular setback in concert with advancement genioplasty. The advancement genioplasty technique was accomplished by maintaining as much soft tissue pedicle as possible to the repositioned chin. A near one-to-one ratio of soft tissue-to-osseous change was achieved in the patient group under study with the use of the described genioplasty technique in combination with mandibular setback by intraoral vertical ramus osteotomies.

Adult↗