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 37 records · Page 2Linked to original sources
PubMed1993

Morphologic and functional implications of the surgical-orthodontic management of mandibular prognathism: a comprehensive review.

The aim of this review is to present the various morphologic and functional implications of the surgical-orthodontic management of mandibular prognathism, thus providing a more complete determination of the efficacy of this modality of treatment. Major conclusions that can be drawn from the bibliography indicate that: (1) After treatment considerable improvement takes place on the soft tissue and dentoskeletal profile, occlusal tooth contacts, and temporomandibular joint function and and pain; (2) Surgical management of mandibular prognathism can be associated with decreased maximum interincisal opening; (3) Although immediately after surgery there is a tendency for the condyles to be distracted downward and anteriorly from their preoperative position, in long-term postsurgery the condyles, on the average, regain their initial position; (4) Compensatory alterations in the pharyngeal, suprahyoid, and infrahyoid muscular regions take place postoperatively; (5) Skeletal changes after mandibular setback to correct mandibular prognathism occur frequently, but their magnitude and patterns exhibit variation and are not necessarily detrimental; and (6) Fulfillment of expectations toward surgical-orthodontic management of mandibular prognathism was reported to be frequent.

Bite Force↗
PubMed2000

Three-dimensional morphology of the masseter muscle in patients with mandibular prognathism.

OBJECTIVE: To compare the morphology of the masseter muscle in patients with mandibular prognathism with that of normal subjects. METHODS: Three-dimensional X-ray computed tomography (CT) was performed on 69 patients with mandibular prognathism and compared with 91 normal subjects. The angle of the muscle direction in relation to the Frankfurt horizontal plane and the area and the ratio of length of the short to long axes (s/l ratio) on the section perpendicular to the muscle direction were measured. RESULTS: The mean angle, area and s/l ratio in patients with mandibular prognathism was 76.6 degrees (s.d. 4.4 degrees), 318.3 mm2 (s.d. 77.2 mm2) and 0.312 (s.d. 0.049), respectively. Those of the normal subjects were 65.1 degrees (s.d. 4.4 degrees), 368.3 mm2 (s.d. 97.2 mm2) and 0.393 (s.d. 0.054), respectively. The angle was significantly larger, and the area and s/l ratio were significantly smaller than those of normal subjects (P < 0.001). CONCLUSION: The morphology of the masseter muscle in mandibular prognathism is significantly different from that of normal subjects. Our results may be helpful in evaluating the results of orthognathic surgery.

Adolescent↗
PubMed1996

Surgical refinement of the operative procedure for a minor degree of mandibular prognathism.

Although sagittal splitting ramus osteotomy is used widely for mandibular prognathism and even for that of a minor degree, a long duration of preoperative and postoperative orthodontic treatment is required. Conversely, mandibular segmental osteotomy has often been used to correct a minor degree of mandibular prognathism without specific orthodontic treatment. Here we describe a surgical refinement accomplishing mandibular segmental osteotomy, reduction genioplasty by double horizontal osteotomies, and decortication of the middle portion of the osteotomies for a minor degree of mandibular prognathism. The amount of setback is limited to 4 to 5 mm, no intermaxillary fixation is required, and no orthodontic treatment, in principle, is needed. This procedure can obtain a rapid aesthetic improvement. We used this procedure in 11 patients (7 females and 4 males) with a minor degree of mandibular prognathism. The amount of setback of the mandibular anterior portion was 4 to 5 mm, and satisfactory results were obtained in all patients.

Adolescent↗
PubMed1996

Tongue volume in human female adults with mandibular prognathism.

It has often been hypothesized that a large tongue leads to an enlargement of the mandible and therefore contributes to the development of mandibular prognathism. We examined (1) whether the tongue volume in human subjects with mandibular prognathism was larger than that in subjects with good occlusion and (2) whether the tongue volume and the pharyngeal capacity correlated with the morphological characteristics of dento-skeletal structures. Magnetic resonance images of the tongue and its surrounding structures were recorded for female adult volunteers with good occlusion (control group, n = 10) and patients with mandibular prognathism (test group, n = 16). Lateral cephalograms were obtained for the patients. No significant differences were determined for the tongue volume or the pharyngeal capacity between the two groups. The tongue volume did not correlate with the pharyngeal capacity (r = 0.280, p = 0.166). The tongue volume correlated with the facial angle (r = 0.548, p = 0.028), the Y-axis (r = 0.539, p = 0.031), and the angle nasion-A point-pogonion (r = 0.540, p = 0.031). These results suggest that the tongue volume is accounted for by the combined horizontal and vertical location of the chin and symphysis, but do not support the conventional clinical surmise that large tongue volume is inherent in patients with mandibular prognathism.

Adult↗
PubMed2003

Segregation analysis of mandibular prognathism in Libya.

The etiology of mandibular prognathism has been attributed to various genetic inheritance patterns and some environmental factors. The variation in inheritance patterns can be partly due to the use of different statistical approaches in the respective studies. The objective of this study was to investigate the role of genetic influences in the etiology of this trait. We performed segregation analysis on 37 families of patients currently being treated for mandibular prognathism. Mandibular prognathism was treated as a qualitative trait, with cephalometric radiographs, dental models, and photographs used to verify diagnosis. Segregation analysis of a prognathic mandible in the entire dataset supported a transmissible Mendelian major effect, with a dominant mode of inheritance determined to be the most parsimonious.

Adult↗
PubMed2006

Herbst treatment of Class II division 1 malocclusions in retrognathic and prognathic facial types.

OBJECTIVE: The aim of this retrospective pilot study was to analyze and compare the short-term and long-term changes of Herbst treatment in Class II division 1 subjects of the retrognathic and prognathic facial type. MATERIALS AND METHODS: The subject material comprised 10 retrognathic (mean SNA = 74.5 degrees, SNB = 70.4 degrees, ML/NSL = 41.1 degrees) and 16 prognathic (mean SNA = 86.7 degrees, SNB = 81.5 degrees, ML/NSL = 25.1 degrees) Class II division 1 subjects treated with the Herbst appliance for an average period of 7 months. Lateral head films from before (T1), immediately after (T2), 12 months after (T3), and 39 months after (T4) Herbst treatment were analyzed with the SO-analysis (analysis of changes in sagittal occlusion) and standard cephalometrics. RESULTS: During the treatment period (T2-T1) the two facial type groups showed similar favorable changes for all variables. During the posttreatment periods of 12 months (T3-T2) and 39 months (T4-T2) recovering changes occurred. In the long-term, a tendency of more unfavorable growth changes was stronger (not significant) for retrognathic subjects than for prognathic subjects. CONCLUSION: On a long-term basis, retrognathic subjects are prone to exhibit more unfavorable mandibular growth changes than prognathic subjects and, thus, might exhibit a greater risk for an occlusal relapse when a stable Class I occlusion is not attained after treatment.

Adolescent↗
PubMed1993

Morphologic airway changes after mandibular setback osteotomy for prognathism with and without cleft palate.

This study illustrates morphologic changes of the pharyngeal airway after mandibular setback osteotomy. Twenty-six patients with prognathism were evaluated preoperatively and postoperatively with standard lateral cephalograms to assess craniofacial morphology--in particular, airway size. Subjects were classified into two groups: those with mandibular prognathism and those with mandibular prognathism accompanied by maxillary hypoplasia caused by cleft palate. In the postoperative period, the width of the pharyngeal airway significantly diminished in both groups; the airway widths of those with maxillary hypoplasia were narrower than those without maxillary hypoplasia. These results indicate that mandibular setback osteotomy induces the narrowing of the pharyngeal airway, and the narrowing effect of this surgery was more pronounced in prognathic patients accompanied by maxillary hypoplasia caused by cleft palate.

Adolescent↗
PubMed1998

Evaluation of the profile line in prognathic patients in the Saxony-Anhalt region of Germany.

The aim of the present study was to investigate the soft-tissue morphology and profile line of prognathic patients in the Saxony-Anhalt region of central Germany. To this effect, the profile photographs and lateral cephalograms taken at treatment start for 34 adults (17 female patients, mean age: 22.6 years; 17 male patients; mean age: 23.2 years), Class III subjects who had not undergone orthodontic treatment, were measured and, by means of statistical analysis, the findings were compared with those of an age-matched control group (17 female subjects, mean age: 21.4 years; 17 male subjects, mean age: 23.8 years). Patients with Class III anomalies had a significantly longer and thinner lower lip and a smaller lower subnasal angle than the control subjects. The lower face was markedly enlarged. Furthermore, the osseous profile line was significantly flatter and the soft-tissue convexity was considerably reduced compared with the control group. Hence the prognathic patients of central Germany manifested typical features of the prognathic profile line. To elucidate typical regional features, further comparative studies are required.

Adolescent↗
PubMedDate not supplied

Mandibular symphyseal contouring in mild mandibular prognathism.

Kölle's mandibular segmental osteotomy, with extraction of the bilateral first bicuspids, is often used in cases of mild mandibular prognathism. While mandibular prognathism is usually corrected by mandibular ramus osteotomy and the mandible is set back en bloc, the premolar region alone is set back by segmental osteotomy, retaining the protruding mental area. In Asians, particularly, the protruding chin is not preferred by our concepts of beauty. In mandibular segmental osteotomy, the entire mandibular symphyseal shape should be considered. Mandibular symphyseal contouring constitutes setting back the premolar region by segmental osteotomy, recession genioplasty, and chiseling out the protruding middle portion of the protruding chin. In 18 series of mild manibular prognathism in Asians patients, this procedure was used and satisfactory aesthetic results were obtained.

Adolescent↗
PubMed1990

Reaction of mastication to occlusal changes induced by correction of mandibular prognathism.

Incisor-point masticatory movements of 22 patients were recorded before and after correction of mandibular prognathism. Chewing patterns and movement parameters were compared between preoperative and postoperative states and to corresponding quantities of 85 persons with normal dentitions. The prognathism patients most frequently revealed "chopping-type" patterns characterized by nearly vertical closing strokes, whereas mastication in the reference group was dominated by lateral grinding-type movements. There were no significant differences in the pattern distributions and parameter values between the preoperative and postoperative states. An individual assessment, considering random fluctuations of chewing behavior, showed that only five patients had changed their chewing mode possibly because of the treatment. Only a minor part of these changes could be directly related to the altered occlusion. It is concluded that the characteristic chewing mode of persons with mandibular prognathism does not interfere with the occlusal profile, and hence does not react to alterations.

Adult↗
PubMed1996

Bite forces before and after surgical correction of mandibular prognathism.

PURPOSE: The purpose of this investigation was 1) to compare morphologic parameters and voluntary bite forces between controls and a sample of patients with mandibular prognathism before surgical correction, and 2) to examine how these patients' bite forces adapt after treatment. PATIENTS AND METHODS: Twenty-four prognathic patients were compared with 24 controls before and up to 3 years after mandibular setback surgery. Measures of skeletal morphology and maximum isometric bite force were made on all subjects over time. Statistical analysis compared the controls, the patients before surgery, and the patients after surgery. RESULTS: Surgical shortening of the mandible averaged 4.1 mm, bringing most skeletal measures into the normal range. Before surgery, the jaw muscle mechanical advantages for patients were significantly smaller than for controls; surgery did not significantly change this relationship. Before surgery the patients had maximum isometric bite forces that were significantly less than those of controls. Bite forces steadily increased after surgery, approaching normal values within 2 to 3 years. CONCLUSIONS: The results of this study suggest that correction of mandibular prognathism by mandibular setback surgery produces some significant functional benefits.

Adolescent↗
PubMed1998

Changes in bite force and occlusal contacts in patients treated for mandibular prognathism by orthognathic surgery.

PURPOSE: The purpose of this study was to evaluate changes in bite force and occlusal contacts before and after orthognathic surgery in patients with mandibular prognathism and to compare the findings with those in controls with normal occlusion. PATIENTS AND METHODS: Bite force and occlusal contacts were analyzed in 23 (7 male and 16 female) patients with mandibular prognathism before and after sagittal split ramus osteotomy, and in 20 (10 male and 10 female) controls with normal occlusion. The bite force and occlusal contacts were simultaneously measured by a computerized occlusal analysis system, the T-Scan system, immediately before surgery, and at 6 weeks, 3 months, 6 months, and 1 year postoperatively. RESULTS: Both the bite force and occlusal contacts in the patients were significantly less than those in the controls before surgery. Although both the bite force and occlusal contacts in the patients were improved by the orthognathic surgery, neither approached the level in the controls within 1 year. Bite force was correlated with the number of occlusal contacts in both patient and control groups. CONCLUSION: The postoperative masticatory function does not reach control levels even 1 year after the orthognathic surgery for mandibular prognathism. Therefore, further adjustment of the occlusion should be considered before the end of treatment.

Adult↗
PubMed1976

Indications for reduction of tongue in surgical treatment of mandibular prognathism.

The literature suggests that the tongue plays an important role in the recurrence after operative correction of mandibular prognathism. To prevent such a recidivism a reduction of tongue can be considered. However, it is difficult to decide how the tongue is involved. Size, strength and function are difficult to measure, and the literature on this subject is not concerned with these properties. A number of methods are given with which an impression can be acquired about the above-mentioned properties of the tongue. Special attention is paid to the type of the ostectomy, and the arguments for this procedure are exemplified by the investigation of 75 patients in whom a surgical correction of mandibular prognathism was performed. It is concluded that tongue reduction is more readily indicated preparatory to correction of mandibular prognathism by a modified Kole procedure than before correction by means of a stepped ostectomy or an Obwegeser-Dal Pont procedure.

Glossectomy↗
PubMedDate not supplied

A new osteotomy for the correction of mandibular prognathism: techniques and rationale of the intraoral vertico-sagittal ramus osteotomy.

The sagittal split ramus osteotomy (SSRO) and the intraoral vertical ramus osteotomy (IVRO) are long established methods for correcting mandibular prognathism, each having its own advantages. However, both procedures have the same disadvantage: the potential for postoperative condylar displacement. The displacement of the condyle is mainly due to the fact that the osteotomy plane is not parallel to the original sagittal plane in which the mandible is repositioned. The author has developed a new ramus osteotomy since 1985 in which the osteotomy plane is theoretically parallel to the original sagittal plane and thereby attempting to decrease the incidence of condylar displacement. This osteotomy was designed additionally to decrease neurosensory disturbances and has the advantages of both methods, and therefore has been named 'intraoral vertico-sagittal ramus osteotomy (IVSRO)'. Initial experience with the 24 prognathic patients operated on by means of the IVSRO indicated excellent clinical results. It has been noted clinically that the IVSRO is very effective in reducing postoperative iatrogenic TMJ symptoms and in treating preoperative TMJ symptoms. It has the additional effect of reducing neurosensory disturbances. This osteotomy seems to be more applicable in mandibular prognathism with excessive flaring of the ramus, particularly that associated with TMJ dysfunction, because the IVSRO has a 'condylotomy effect' and its splitting plane diverges less from the original sagittal plane than that of the SSRO and the IVRO.

Bone Screws↗
PubMed1977

The role of dental compensations in the orthodontic treatment of mandibular prognathism.

Thirty-six patients with orthodontically treated mandibular prognathism were recalled for cephalometric and clinical evaluation. A comparison group of 32 non-Class III patients was similarly examined. Analysis of variables associated with the anterior dentition and documentationtion of labial gingival recession and tooth mobility led to the following conclusions concerning the role of dental compensations in the orthodontic treatment of mandibular prognathism. 1. Vertical and horizontal dental compensations were quantitated in the dentition of the study group (pretreatment to postretention). 2. Increased labial gingival recession and increased tooth mobility in functional jaw positions were present in anterior maxillary and mandibular teeth of the study group relative to the comparison group. 3. Proper diagnosis and the establishment of realistic treatment objectives by clinician and patient are necessary to avoid undesirable sequelae and/or undesirable facial esthetics in the treatment of mandibular prognathism.

Humans↗
PubMed2004

Post-operative optimization of gum-chewing kinematics in a prognathic patient.

Smooth jaw movements during gum chewing, which are defined as those driven by optimally smooth patterns of temporal change in acceleration/deceleration, have been quantified in subjects with acceptable occlusions. This paper reports a case in which significant improvement of the smoothness of masticatory jaw movement was observed following surgical-orthodontic treatment. A patient, who demonstrated a mandibular prognathism, underwent the treatment. The irregularity in acceleration/deceleration of jaw closing movement during gum chewing was quantified by the movement jerk-cost, where the jerk is rate of change in movement acceleration/deceleration. The normalized jerk-costs and results of maximum-smoothness model simulation were compared between jaw movements at pre- and post-treatment stages. The correction of mandibular prognathism and crossbite allowed the patient to close the jaw with wider lateral excursion. Furthermore, smoothness of the jaw closing movements increased significantly and the velocity profile was characterized as similar to that predicted by the kinematic model after treatment. These findings for achievement of 'functional occlusion' that allows the patient to perform smooth and economical jaw closing movements during chewing demonstrate necessity of orthodontic treatment of mandibular prognathism to improve jaw motor function.

Adult↗
PubMed2001

Changes in bite force and occlusal contact area after orthognathic surgery for correction of mandibular prognathism.

OBJECTIVE: This study examined the long-term changes of bite force and occlusal contact area in patients with prognathous after orthognathic surgery with a newly developed pressure-sensitive sheet (Dental-Prescale; Fuji Photo Film Co). STUDY DESIGN: Fifty-seven patients with prognathous were examined. Bite force and occlusal contact area were measured just before operation and at 2 weeks, 1 month, 3 months, 6 months, 1 year, 2 years, and 3 years after operation. Forty control subjects with normal occlusion were also measured. RESULTS: The bite force and occlusal contact area of the patients were significantly greater than the preoperative level at 1 year, 2 years, and 3 years after operation. However, they were still significantly lower than the control subject level even at 3 years after operation. CONCLUSIONS: This study suggests that orthognathic surgery improves the bite force and occlusal contact area of patients with prognathous. However, at 3 years from the time of operation, patients had not reached control subject levels.

Adolescent↗
PubMed1991

The functional status of orthodontically treated prognathic patients.

In order to study the prevalence of mandibular dysfunction in orthodontically treated prognathic patients after retention, 60 randomly selected patients were examined clinically. The functional status of the patients was evaluated using the anamnestic, clinical dysfunction index, and the index for occlusal status introduced by Helkimo. Our patients showed a better functional status than the untreated prognathic patients, but one poorer than that of the general population. No difference, as demonstrated by indices, could be found between chin-cup and non chin-cup group, or between the conservatively treated and surgically treated prognathic patients without pre-orthodontic treatment.

Adolescent↗