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PubMedDate not supplied

[Relation between atlas position, prognathism and prognathous jaw anomalies].

The position of the 1st cervical vertebra is investigated in relation to special anomalies of the craniofacial morphology. Two extremely different types like prognathism and progenia are chosen to demonstrate an interdependence. The latter is probably caused by a different head posture which in itself is influenced by the maxillo-facial anomalies. With the aid of the literature the findings can be explained on a functional basis.

Adolescent↗
PubMed1980

[The effect of prognathism surgery on the temporomandibular joint. (A clinical and radiological evaluation of temporomandibular joint changes after various methods of surgery for prognathism)].

On the basis of clinical and roentgenologic examinations of progenia patients which were planned according to our occlusal concept and monitored postoperatively, we established that the condylar displacement in the roentgenogram offers an exact parameter for the extent of operative displacement of the condyles. Nevertheless, a direct conclusion concerning the clinical symptoms or freedom of complaints cannot be established on the basis of this roentgenographic analysis. The roentgenogram also showed considerable condylar alterations in patients with temporomandibular joint symptoms; greater displacement of the condyles was frequently demonstrable with temporomandibular joint complaints.

Humans↗
PubMed2005

Mandibular prognathism in Japanese families ascertained through orthognathically treated patients.

INTRODUCTION: Patients with severe mandibular prognathism frequently require orthognathic surgery to correct skeletal disharmony. Genetic and environmental factors are suggested in the etiology of mandibular prognathism, but the precise contribution of these factors is unknown. METHODS: To clarify the impact of genetic factors on mandibular prognathism, we gave a questionnaire to 105 subjects with severe skeletal Class III mandibular prognathism who planned to undergo or had undergone orthognathic surgery. The questionnaire assessed mandibular prognathism in 3 generations of each subject's family. All answers were confirmed in a careful interview that included differentiation of "maxillary deficiency" and "mandibular excess." This is the first 3-generation family study of mandibular prognathism in orthognathically treated patients. RESULTS: The average ANB, SNA, and SNB angles in the probands were -3.7 degrees , 80.9 degrees , and 84.6 degrees, respectively. A total of 1480 family members were examined, and 11.2% had mandibular prognathism. Men were slightly more affected than women; 68.6% of families had at least 1 member other than the proband with mandibular prognathism. The affected ratio of first-degree relatives was more than twice that of second-degree relatives (17.5% and 7.6%, respectively). There was no difference in the occurrence between fathers and mothers of probands, and siblings showed a high affected ratio of 25.0%. Falconer's heritability was calculated as 84.3% in first-degree relatives. CONCLUSIONS: A high occurrence of mandibular prognathism was seen in families of orthognathically treated skeletal Class III patients, suggesting a profound genetic influence.

Adult↗
PubMed1999

Temporomandibular joint symptoms and disc displacement in patients with mandibular prognathism.

Our objective was to find out the incidence of signs and symptoms of temporomandibular joint (TMJ) and disc displacement in patients with mandibular prognathism. Fifty-one patients were examined clinically and by axial computed tomography(CT). The incidence of TMJ signs and symptoms was 6/25(24%) in patients with simple mandibular prognathism and 12/26(46%) in patients with mandibular prognathism and asymmetry. No discs were displaced in patients with simple mandibular prognathism, but 15(58%) of the patients with mandibular prognathism and asymmetry had displaced discs. There was no association between signs and symptoms of TMJ and disc displacement. Patients with mild protrusion and severe asymmetry of the mandible had a high incidence of disc displacement, which interestingly was on the deviated side in 14 of the 15 patients affected. We conclude that skeletal morphology may have a role in the development of TMJ disorders but the mechanism is obscure.

Adolescent↗
PubMed2004

Computer-assisted morphological analysis of dental casts with maxillary prognathism and reversed occlusion.

The morphologic characteristics of the dentition with maxillary prognathism and reversed occlusion were examined by a computer-assisted dental cast analysing system. Dental casts with normal occlusion, maxillary prognathism and reversed occlusion were selected and measured by a 3D shape measuring system. The dental arches and anteroposterior occlusal curves were approximated numerically by the polynomial expression with a fourth order and second order coefficients, respectively. The coefficients were analysed statistically. Maxillary dental arches with mandibular prognathism showed a more acuminate shape (V-shape) with a significant larger second order coefficient, while arches with reversed occlusion showed more angulate shapes (U-shape) with significantly smaller second order coefficients compared with arches with normal occlusions. However, a notable difference in the shape of the mandibular dental arches was not observed. The mandibular dental arches with maxillary prognathism were positioned backward relative to maxillary dental arches, while the arches with reversed occlusion were positioned forward. The anteroposterior occlusal curves with maxillary prognathism showed larger curvatures in maxilla and mandible, while the curves with reversed occlusion showed smaller curvatures in mandible comparing with the curves with normal occlusion. These results suggest that the present method could offer a useful and objective examination technique for the diagnosis of malocclusion.

Adolescent↗
PubMed2006

Craniofacial morphometric analysis of mandibular prognathism.

The purpose of this study was to provide more information about the morphological characteristics of the craniofacial complex in mandibular prognathism. Forty young adult males having mandibular prognathism were compared with 40 having normal occlusion. This was conducted to carry out geometric morphometric assessments to localize alterations, using Procrustes analysis and thin-plate spline analysis, in addition to conventional cephalometric techniques. Procrustes analysis indicated that the mean craniofacial, midfacial and mandibular morphology was significantly different in prognathic subjects compared with normal controls. This finding was corroborated by the multivariate Hotelling T(2)-test of cephalometric variables. Mandibular prognathism demonstrated a shorter and slightly retropositioned maxilla, a greater total length and anterior positioning of the mandible. Thin-plate spline analysis revealed a developmental diminution of the palatomaxillary region anteroposteriorly and a developmental elongation of the mandible anteroposteriorly, leading to the appearance of a prognathic mandibular profile. In conclusion, thin-plate spline analysis seems to provide a valuable supplement for conventional cephalometric analysis because the complex patterns of craniofacial shape change are visualized suggestive by means of grid deformations.

Adult↗
PubMed1999

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

OBJECTIVE: To examine post-operative stability in prognathic patients with mandibular asymmetry who underwent sagittal split ramus osteotomy (SSRO) of the mandible and titanium screw fixation without post-operative maxillomandibular fixation (MMF). DESIGN: Skeletal and dental changes after surgery with and without post-operative MMF were compared between prognathic patients with symmetric and asymmetric mandibles. SETTING AND SAMPLE POPULATION: Second Department of Oral and Maxillofacial Surgery at Tokyo Medical and Dental University. Twenty prognathic patients were examined. EXPERIMENTAL VARIABLE: An appliance for repositioning the proximal segment was applied in all 20 patients. Ten patients with symmetric mandibles received post-operative MMF with stainless steel wires and intermaxillary rubber traction after the removal of MMF (Group I), while the other 10 patients with asymmetric mandibles underwent post-operative intermaxillary rubber traction only (Group II). OUTCOME MEASURE: Posteroanterior cephalograms were obtained pre-operatively; 2-3 days post-operatively; and 3, 6, and 12 months after surgery. Changes in the positions of the gonion points (Go) and upper and lower incisors (U-1 and L-1) were examined. RESULTS: In both groups, the Go tended to shift laterally as a consequence of the operation. Although the tendencies of the post-operative changes in the Go points of Groups II and I were different, statistical analyses revealed no significant differences between the two groups. At the last stage of the follow-up period, the absolute value of the change in L-1 tended to be larger in Group II than in Group I, but without any statistical significance. CONCLUSION: This study suggests that post-operative change in prognathic patients with asymmetric mandibles treated without post-operative MMF is comparable to that in patients with symmetric mandibles treated with post-operative MMF. Accordingly, post-operative MMF may be avoided, even in prognathic patients with asymmetric mandibles.

Adolescent↗
PubMed2006

[Contrast analysis of different sagittal split ramus osteotomy methods in correcting mandibular prognathism].

OBJECTIVE: To explore the indication, advantage and disadvantage of modified or classical technique of intraoral sagittal split ramus osteotomy (SSRO) for correction of mandibular prognathism. METHODS: From January 1997 to January 2005, 95 patients suffering from mandibular prognathism or accompanied by other deformities were treated with modified or classical technique of intraoral SSRO. Of 95 cases, there were 34 males and 61 females, aging 15 to 44 years, including 53 cases of single mandibular prognathism, 28 cases accompanied with mandibular deviation, 11 cases accompanied with maxillary retrognathism, 2 cases accompanied with glossacele and 1 case accompanied with malar protrusion. X-ray cephalometry showed: sella-nasion-A point (SNA) 80-83 degrees, sella-nasion-B point (SNB) 80-84 degrees, A point-nasion-B point (ANB)--3-1 degrees. Forty-three cases were corrected by modified SSRO and 52 cases by classical SSRO. RESULTS: The face appearance and dental articulation of all the patients were improved greatly. In patients by classical SSRO, disorder of local sensibility occurred in 9 cases, mandibular fracture during the cleavage of the ascending ramus in 1 case, significant bleeding in 1 case, postoperative infection in 1 case and postoperative relapse in 3 cases. In patients by modified SSRO, disorder of local sensibility occurred in 2 cases and postoperative relapse in 1 case; no mandibular fracture, significant bleeding, postoperative infection and other complications occurred. With a follow-up of 3 months to 7 years, X-ray cephalometry showed SNA 81-83 degrees, SNB 78-81 degrees and ANB 1-4 degrees. CONCLUSION: Modified SSRO is an ideal method of correcting mandibular prognathism, especially severer mandibular prognathism accompanied by mandible deviation deformity.

Adolescent↗
PubMed1977

Differential treatment planning for mandibular prognathism.

The treatment records of thirty-eight cases of mandibular prognathism treated by orthodontics means only (ORTHO) were evaluated. The pretreatment records of twenty cases of mandibular subapical esteotomy (SUB) and twenty cases of mandibular setback (SET) were evaluated for comparison and contrast with the pretreatment ORTHO records and with each other. Dental, skeletal, and soft-tissue parameters in the vertical and horizontal planes of space were recorded. Statistical analysis of means of parameters of the pretreatment records provided documentation of the discriminant variables in each of the following paired groups: ORTHO-SUB, ORTHO-SET, and SUB-SET. Analysis of the data as indicated above led to the following conclusions: 1. Three discriminant groups of mandibular prognathism of various degrees of severity were discernible when comparisons of treatment categories simulating clinical decisions were made. The ORTHO group was distinguished from the SUB group in the horizontal plane and, more strongly, in the vertical plane. The ORTHO group was distinguished from the SET group in the vertical plane and, more strongly, in the horizontal plane. The SUB group was distinguished from the SET group in the horizontal plane. 2. The physiologic developmental status of the patient should be carefully evaluated. 3. Anteroposterior dysplasias should be assessed relative to the cant of the mandibular plane. True denture base discrepancies can be noted relative to the occlusal plane. 4. Documentation of vertical dysplasias should include measurements of craniofacial divergence (SN-MP, FH-MP, and OP-MP). 5. In assessing the profile evaluation of the patient with mandibular prognathism, particular attention should be focused on facial contour angle (FCA), nasolabial angle (NLA), and relative lower lip protrusion (LLP). 6. Any numerical values obtained in the evaluation of the dental, skeletal, or soft-tissue characteristics of mandibular prognathism should be considered only as descriptive, diagnostic guides and not as components of a diagnostic formula.

Alveolar Process↗
PubMed1977

Tooth-size discrepancy in mandibular prognathism.

A Bolton analysis of seventy-eight cases of Angle Class III malocclusion, twenty-six cases of Angle Class I malocclusion, and twenty-six cases of Angle Class II malocclusion was recorded. Frequency of excess mandibular tooth structure, magnitude of the excess, over-all ratios, and anterior segment ratios were computed and analyzed. Two clinical cases were presented to show the advantage of tooth-size harmony in mandibular prognathism. Analysis of the data as presented above suggests the following conclusions: 1. The frequency of mandibular tooth-size excess (over-all ratio) in this sample was greater in cases of mandibular prognathism than in Angle Class I and Angle Class II cases. 2. In those cases with mandibular tooth-size excess, there was a suggestion that the magnitude of the excess was greater in cases of mandibular prognathism than in Angle Class I and Angle Class II cases. 3. A tooth-size discrepancy analysis should be included as one part of the diagnostic records for mandibular prognathism.

Adolescent↗
PubMed2006

Skeletal changes after modified intraoral vertical ramus osteotomy for correction of mandibular prognathism.

BACKGROUND: Orthognathic surgery is widely used to correct congenital and acquired dentofacial discrepancies. Various surgical procedures have been advocated for correction of mandibular prognathism. In this study, a modified intraoral vertical ramus osteotomy has been developed for surgical correction of mandibular prognathism. The aim of this study is to identify contributing factors to skeletal change by analysing cephalometric changes after modified intraoral vertical ramus osteotomy. METHODS: Forty-one patients, treated for absolute mandibular prognathism by bilateral modified intraoral vertical ramus osteotomy, were evaluated cephalometrically with reference to the menton point. A set of four standardised lateral cephalograms were obtained from each subject preoperatively (T1) and immediately postoperatively (T2), prior to removal of maxillomandibular fixation (T3), and at 1-year postoperatively (T4). The mean setback of the menton was 12.4 mm in the horizontal direction. Relapse was defined as forward movement of the menton during the 1-year follow-up. RESULTS: The highly significant backward movements in a horizontal direction were observed during the maxillomandibular fixation period (T3-T2). Moreover, highly significant forward movement was observed following the maxillomandibular fixation period (T4-T3). After 1-year follow-up (T4-T2), the mean changes of the menton were 0.1 mm backward in the horizontal direction. CONCLUSIONS: In this series, the mean skeletal change compared with the amount of setback was less than 1% (0.1/12.4 mm) in backward movement. The results suggest that the modified intraoral vertical ramus osteotomy technique is useful and the more stable approach for correction of severe mandibular prognathism.

Adolescent↗
PubMed2004

Transitional joint effusion in the mandibular prognathic surgery patient: intraoral vertical ramus osteotomy versus sagittal split ramus osteotomy.

PURPOSE: The purpose of this study was to examine the cause of joint effusion (JE) appearing postoperatively in the temporomandibular joint (TMJ) of patients with mandibular prognathism on T2-weighted magnetic resonance (MR) images. PATIENTS AND METHODS: MR imaging was performed before and after surgery in 30 TMJs of 15 subjects with mandibular prognathism who underwent intraoral vertical ramus osteotomy (IVRO) and in 20 TMJs of 10 subjects with mandibular prognathism who underwent sagittal split ramus osteotomy (SSRO). The preoperative MR imaging was performed 1 month before surgery, and postoperative MR imaging was performed during maxillomandibular fixation. RESULTS: Preoperatively, none of SSRO and IVRO groups had JE. Postoperatively, 12 TMJs (40%) of the IVRO group and only 1 TMJ (5%) of the SSRO group had JE. As for the TMJs in the IVRO group, on MR imaging, the degree of downward movement of the condyle after surgery was larger in TMJs with JE (3.8 +/- 2.3 mm) than in TMJs without JE (1.8 +/- 1.6 mm). JE diminished within about 4 months after removal of the maxillomandibular fixation. CONCLUSION: JE appearing postoperatively in the TMJ of patients with mandibular prognathism might be relation to the degree of downward movement of the condyle.

Adolescent↗
PubMed2006

Relationship between the morphologies of the masseter muscle and the ramus and occlusal force in patients with mandibular prognathism.

PURPOSE: The purpose of this study was to examine the relationship between the morphologies of the masseter muscle and the ramus and occlusal force in patients with mandibular prognathism. PATIENTS AND METHODS: The study group consisted of 71 patients with mandibular prognathism. They were divided into 2 groups, consisting of prognathism with or without symmetry, determined by frontal cephalogram analysis. All patients underwent 3-dimensional (3D) computed tomography (CT) and occlusal force was recorded with pressure-sensitive sheets. RESULTS: In the cross-sectional area of masseter muscle, there were no significant differences between the right and left sides in the symmetry and asymmetry groups. In occlusal force, there was no significant difference between the symmetry and asymmetry groups. Occlusal force was not significantly correlated to the cross-sectional area of the ramus, but it was significantly positively correlated to the cross-sectional area of the masseter muscle (P < .05). CONCLUSION: Occlusal force was associated with the ipsilateral cross-sectional area of masseter muscle in patients with prognathism; however, it was not associated significantly with the degree of mandibular deviation.

Adolescent↗
PubMed1993

Growth of mandibular prognathism after pubertal growth peak.

This study deals with the growth changes of the Japanese face associated with mandibular prognathism during 3 years after the pubertal growth peak. The investigation was based on the serial lateral cephalometric roentgenograms of prognathic and normal males and females, respectively. Maturational stages of the pubertal growth were determined individually by the ossification events taken from hand-wrist radiographs. Results indicate that the morphologic characteristics of the mandibular prognathism, which are established before the pubertal growth peak, are strongly maintained during the period studied. However, mandibular prognathism seems to show a manner of growth change fairly similar to that of the normal after the pubertal growth peak.

Adolescent↗