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At least 145 records · Page 8Linked to original sources
PubMed1992

Craniomandibular dysfunction following surgical correction of mandibular prognathism.

Craniomandibular function was studied in 36 adult patients in whom mandibular prognathism was corrected with a combination of surgical (vertical ramus osteotomy) and orthodontic procedures. Each patient was examined up to 1 week before surgery and again 6 months later. Mandibular mobility, impaired function of the temporomandibular joint, and pain in the masticatory muscles and temporomandibular joint were evaluated. Data were classified according to a numerical scale and patients were divided into three groups: symptom free, mild symptoms and severe symptoms. Although there was no difference in the overall frequency of the three functional groups during the two phases of examination, 20 patients showed a change in functional status following surgery. Before surgery, decreased mandibular mobility was found in 19 patients; after surgery, four additional patients were included in this group. Temporomandibular joint function improved in 10 patients and three patients had less pain. The frequency of muscle pain did not change. Postoperative maximal interincisal opening was reduced by 5.4 mm (p less than 0.001) but lateral excursive movements did not change significantly. No significant relationships were found between pre- and postoperative mandibular mobility, temporomandibular joint function and muscle pain. Females experienced mild or severe dysfunction more often than males at both examinations, but the difference was not statistically significant.

Adolescent↗
PubMed2001

Alteration of the angle of the coronoid process in prognathism.

Muscles and bones may dynamically affect the functions of each other, resulting in changes in the activity of the muscle and/or morphological change in the bones. However, alterations of the morphology of the coronoid process have not been documented in relation to the temporal muscle between the mandible and the cranium. Angles of the coronoid process to the line through the right and the left frontotemporale were measured on posteroanterior (PA) cephalograms in patients with normal occlusions and Class II, division 1 malocclusions, and those with true skeletal Class III malocclusions. Standard deviation of the angle of the coronoid process in patients with Class III malocclusions was greater than those subjects with normal occlusion or Class II, division 1 malocclusions. Differences of angles between the right and the left coronoid process in each patient of either sex were significantly large in true skeletal Class III malocclusions (both P < 0.001). Large variation of angle of the coronoid process was related to prognathism, and this effect may represent adaptation of temporal muscle function to a variety of alterations in mandibular morphology.

Adaptation, Physiological↗
PubMed2003

Relationship of the hyoid bone and posterior surface of the tongue in prognathism and micrognathia.

In order to study relationship of the hyoid bone and posterior surface of the tongue in prognathism and micrognathia, we focused on the effect of the tongue on the upper airway lumen in 16 patients with Angle's Class II and 51 patients with Angle's Class III, and assessed the position of the hyoid, the depth from the posterior surface of the tongue, from the bottom of the vallecula and from hyoid bone to the posterior pharyngeal wall using lateral cephalograms. We were able to assess significant correlations between the posterior surface of the tongue and hyoid position in Angle's Class III. However, we found no association between them in Angle's Class II. This could be an adaptive feature of the genioglossus in response to hyoid localization to serve a compensatory role to prevent respiratory impairment in micrognathia at risk of apnoea.

Adolescent↗
PubMed2001

Changes in masticatory function after orthognathic treatment in patients with mandibular prognathism.

Changes in masticatory function were measured in 27 patients in whom mandibular prognathism was corrected surgically. The mean value of masticatory efficiency before treatment was 46% of that of control subjects with normal occlusion. It improved, but remained at 60% of the control value postoperatively. Similar changes were seen in the number and area of occlusal contacts and the integrated muscle activities of the masseter and temporalis on the chewing side, but the postoperative improvement in masticatory efficiency was mainly the result of improvement in masseter activity. The mean values of masticatory cycle variables in the patient group did not differ significantly from those of the controls. Their preoperative mean coefficients of variation, which were significantly higher than those of the controls, decreased significantly postoperatively. These results suggest that the stability of masticatory rhythm was improved by orthognathic surgery.

Adolescent↗
PubMed2001

Changes in occlusal state of patients with mandibular prognathism after orthognathic surgery: a pilot study.

This study examined the occlusal state of patients with mandibular prognathism and compared it with that of adults with normal occlusion (controls). It also examined changes in occlusal state after orthognathic operations in these patients. The values of occlusal contact area and bite force in patients before operation were significantly lower than in controls, and occlusal pressure in patients was higher than in controls. The occlusal contact area and bite force of the patients 1 month after the operation had decreased to below preoperative values. These values 12 months after the operation had increased by 2.0 and 1.8 times in women and 1.4 and 1.4 times in men, respectively, compared with preoperative values. However, absolute values remained extremely low compared with those of controls. In contrast to the above, occlusal pressure reached its maximum value 1 month after the operation and at 12 months it was close to the value for controls.

Adult↗
PubMed2001

Plate fixation of extra-oral subcondylar ramus osteotomy for correction of mandibular prognathism: clinical aspects and short term stability.

AIM: The present study describes an extra-oral approach for subcondylar oblique ramus osteotomy using stable fixation for setback of the mandible. The aim was to investigate the incidence of neurosensory disturbances of the mandibular nerve, evaluate facial scar appearance, and assess skeletal stability following the procedure. METHODS: Forty-two consecutive patients with mandibular prognathism were operated upon using the subcondylar oblique ramus osteotomy and plate fixation. The patients were followed up for 6 months following surgery. Intra-operative and postoperative complications, neurosensory function, and facial scar characteristics were recorded. Lateral cephalograms were available immediately before operation, and immediately after operation and 6 months postoperatively. Skeletal stability was based on cephalometric assessment. RESULTS: Among the 19 patients operated earliest, neurosensory disturbances were recorded in five individuals at the 6 month follow-up. In the subsequent group of 23 patients, no disturbances were reported. All but two patients were not concerned about the facial scar 6 months postoperatively. Mean anterior relapse at the 6 month follow-up was 0.5 mm, representing 9% of the surgical setback. CONCLUSION: Extra-oral subcondylar oblique ramus osteotomy with plate fixation is a stable procedure with a low incidence of neurosensory disturbances if the osteotomy is placed well behind the mandibular foramen. Facial scar appearance was rarely a matter of concern to the patients.

Adult↗
PubMed2002

Positional stability following intentional posterior ostectomy of the distal segment in bilateral sagittal split ramus osteotomy for correction of mandibular prognathism.

PURPOSE: In order to minimize post-operative relapse after mandibular setback using bilateral sagittal split ramus osteotomy, we have recently tried a technique, i.e. intentional ostectomy of the posterior part of the distal segment. The aim of this study was to evaluate the effects of this technique on the frequencies and extent of post-operative relapse. PATIENTS: This study was based on 61 cases of mandibular prognathism. The traditional sagittal split was performed in 24 cases (average age: 22.0+/-3.8) as a control group and the technique of additional distal ostectomy was used in the other 37 cases (average age: 23.2+/-3.2) as a test group. METHODS: Horizontal and vertical changes in the position of the body of the mandible were measured to determine the amount of long-term post-operative relapse. The amount of relapse was compared between groups and the statistical significance of the differences was evaluated. RESULTS: The relapse index of the test group was significantly lower than that of the control group in the 6- and 12-month post-operative periods (p>0.005). The horizontal relapse index and facial length relapse index of the test group were lower than those of the control group 12 months post-operatively (p<0.05). CONCLUSION: This method should be considered as a useful method to maximise long-term post-operative stability.

Adult↗
PubMed2003

Changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery.

OBJECTIVE: We sought to evaluate the changes in bite force and dentoskeletal morphology in prognathic patients after orthognathic surgery. STUDY DESIGN: Twenty-four patients underwent orthognathic surgery to correct Class III skeletal and dental malocclusions. Ten patients who underwent Le Fort I and bilateral sagittal split ramus osteotomy of the mandible (ie, surgical correction of 2 jaws) and 14 patients who underwent only bilateral sagittal split ramus osteotomy (ie, surgical correction of 1 jaw) were compared. Bite force was measured preoperatively and at 3, 6, and 12 months postoperatively. The dentoskeletal morphology was assessed through lateral cephalograms obtained preoperatively and 12 months postoperatively. RESULTS: Twelve months postoperatively, the bite force was significantly greater in the patients who underwent surgery on 1 jaw than in the patients who underwent surgery on 2 jaws. Significant decreases in the gonial angle, occlusal plane angle, and anterior facial height were observed postoperatively in the patients with 1 surgically corrected jaw, but not in the patients with 2 surgically corrected jaws. Patients with 2 surgically corrected jaws experienced a greater increase in the Frankfort mandibular plane angle and a greater decrease in the posterior facial height than did those with 1 surgically corrected jaw. CONCLUSION: The difference in the preoperative-to-postoperative change in dentoskeletal morphology between the 2 groups is one of the factors responsible for the significant difference in postoperative bite force between the 2 groups.

Adolescent↗
PubMed2002

Relationship between occlusion and EMG activity of the masseter muscles during clenching at maximal intercuspal position: a comparative study between prognathics and controls.

In the prognathic (P) patient group clenching at maximal intercuspal position (MIP), we found that the Ar-Go-Me angle is greater than in the control group (C = 120.9 degrees +/- 7 degrees vs. P = 134.4 degrees +/- 5.2 degrees): the same as the masseter fibers angle (alpha). The average EMG voltage class was similar in both groups (C = 1488.5 +/- 303.4 microvolt vs. P = 1317.6 +/- 293.4 microvolt). The mean total number of contact points in tooth arches was greater in the control group than in the patient group (C = 5.77 +/- 0.43 vs. P = 3.07 +/- 0.29), and there was a greater number of contact points between both premolar and molar areas. Both the control group and the patient group showed balanced occlusion in the premolar and molar areas. Therefore the finding of a similar mean EMG value between the control group and the patients emphasizes the importance of balanced contact points in the posterior areas.

Adult↗
PubMed1992

Skeletal stability after surgical correction of mandibular prognathism by vertical ramus osteotomy.

The purpose of the study was to assess skeletal stability following combined surgical-orthodontic management of 52 adults with severe mandibular prognathism. Lateral cephalograms taken 1 week before surgery, within 1 week post-surgery and approximately 1 year after operation were studied by means of eight variables and a constructive stable reproducible reference system. The surgical procedure of choice was a bilateral vertical ramus osteotomy through an extra-oral approach. In all cases the condyles were left passively in the articular fossa and no attempt at their active repositioning was made. The patients were randomly allocated to an osteosynthesis or non-osteosynthesis group with regard to intramandibular fixation. Intermaxillary fixation lasted 6 weeks and an interocclusal wafer was used in all cases during this period. The findings of this study showed that during the post-operative period there was a trend for posterior rotation of the mandibular corpus (P less than 0.001). This pattern was also characterized by an increase (P less than 0.001) of the lower anterior face height and an improvement of the angle of convexity (P less than 0.001). These changes occurring in a direction so that the dentoskeletal profile became less concave, did not tend to reverse the goal of operation and cannot be considered as detrimental. No significant differences (P greater than 0.05) were found between the groups without and with osteosynthesis.

Adolescent↗
PubMed1980

Ancillary procedures in the surgery treatment of prognathism.

After carrying out preoperative and postoperative facial, intraoral, and cephalometric clinical examinations in the prognathism patients studied in our service, we found that 85% of them needed integral aesthetic correction of the face, including procedures in the forehead, nose, lips, and chin. In our series, 55% of the patients underwent additional corrective surgery, 2 of whom are presented.

Adolescent↗
PubMed1981

The combined surgical and orthodontic treatment of mandibular prognathism.

Patients with severe mandibular prognathism are best managed with a combined orthodontic-surgical approach. In our patients, the orthodontic treatment consisted of six to eighteen months of presurgical preparation, which in some patients may accentuate the dental deformity. This is done to provide two well-aligned dental arches that will fit accurately at surgery. The surgical procedure used was an oblique subcondylar osteotomy. This was followed by six to eight months of orthodontic treatment to complete dental alignment. Thirty patients were treated using this combined approach, with excellent results and few complications.

Adolescent↗
PubMed1977

Vertical ramisection for prognathism.

Forty-four patients with Class III malocclusion, who were operated on for prognathism, have been reviewed. In spite of the associated problems of pain, nausea, fear, relapse, additional orthodontia, lip numbness, lip weakness, and 8 weeks with their teeth wired together, only one patient of the 44 said he (or she) would decline this surgery if it were to be considered anew. The surgeon must make a strong effort to keep the vertical cut in the bony ramus posterior to the lingula, to avoid postoperative lip numbness. He should also keep traction on the soft tissues minimal, to avoid postoperative weakness of the lower lip. A significant relapse was uncommon in this series, and the facial symmetry was greatly enhanced. Most of these 44 patients (66 percent) said the improvement in their self-image and personal appearance was far more important to them than the improvement in their bite.

Adolescent↗
PubMed1998

Maxillary distraction: aesthetic and functional benefits in cleft lip-palate and prognathic patients during mixed dentition.

In the last few years, distraction techniques have been used successfully to correct the hypoplastic human mandible. In patients with cleft lip and palate, normal growth of the maxilla may be impaired by early cleft repair, and many of them do not respond to orthodontic procedures alone. Maxillary distraction is an alternative technique to correct maxillary hypoplasia during mixed dentition. In the last 3 years, the procedure was performed in 38 patients aged between 6 and 12 years; 18 patients had unilateral cleft lip and palate, 9 patients had bilateral cleft lip and palate, 7 patients had unilateral cleft palate, 2 patients had prognathism, and 2 patients had nasomaxillary dysplasia. Photographs, posteroanterior and lateral cephalograms, and dental models are obtained preoperatively (as well as an orthopantomogram) to locate the tooth buds. A subperiosteal dissection is performed exposing the anterior and lateral aspects of the maxilla, and an incomplete horizontal osteotomy is done above the tooth buds. Using a facial mask and an intraoral fixed appliance system as an anchorage, we initiate on the fifth postoperative day the application of distraction forces. Maxillary advancement between 4 and 12 mm is achieved during 3 to 4 weeks, and a satisfactory class I or II molar relationship is also obtained. A combination of forward and downward distraction forces can be used to achieve simultaneous advancement and elongation of the hypoplasic maxilla. The aesthetic results are excellent, and the nasolabial angle is increased, including a more anterior projection of the upper lip. Nasal breathing is improved as well as the air flow and patency of the nasal airway. Velopharyngeal function remains unchanged after the procedure. The follow-up in this series varied from 6 months to 3 years. No relapses have been observed.

Child↗
PubMed1982

Lip morphology and area changes associated with surgical correction of mandibular prognathism.

Changes in lip morphology and area, measured in two dimensions from standardized lateral head films, were assessed in a series of twenty adults at three times: pre-surgically, 8--14 months post-surgically, and a long-term follow-up at 5--7 years. All individuals received the same, single surgical procedure (Obwegeser sagittal split for correcting mandibular prognathism. Upper and lower lip changes were quantified as millimetres displacement of the lip centroid vertically and horizontally, plus changes in cross-sectional area. Direction and amount of change, its dependency on the amount and kind of surgically induced symphyseal changes, and the intercorrelations among lips and among lip and symphysis variables were statistically evaluated, both univariately and multivariately. Three measures are made of symphysis change: horizontal and vertical repositioning and amount and direction of rotation. Horizontal repositioning primarily affected the lengthening and areal increase of the upper lip. Vertical repositioning had its major influence in the height and cross-sectional area of the lower lip: a superior shift of the mandible made the lower lip shorter, more protrusive and smaller in area; an inferior shift produced an increase in lower lip height with increased area. The third variable, symphyseal rotation, had its greatest influence on the labial-lingual shift of the upper lip's centroid. The long-term follow-up showed little change from the 1 year post-operative conditions; equilibrium of the soft tissue components was then achieved fairly soon after surgery.

Adult↗
PubMed1996

A history of miscarriages and mild prognathism as possible mode of presentation of mosaic trisomy 18 in women.

A 22-year-old woman seeking medical assistance for hypofertility after two miscarriages had very slight anomalies: mild macrogenia and prognathism, and temporal depilation. Peripheral lymphocytes and fibroblastic karyotypes disclosed the tenth published case of low-level mosaicism for trisomy 18 with normal intelligence. Subfertility is frequently observed among these patients. As women with this anomaly are at risk of trisomy 18 pregnancies and as five cases have been reported recently, this particular chromosomal anomaly may not be so exceptional and should be investigated in cases of hypofertility.

Abortion, Habitual↗
PubMed2002

Sorting nexin 3 (SNX3) is disrupted in a patient with a translocation t(6;13)(q21;q12) and microcephaly, microphthalmia, ectrodactyly, prognathism (MMEP) phenotype.

A patient with microcephaly, microphthalmia, ectrodactyly, and prognathism (MMEP) and mental retardation was previously reported to carry a de novo reciprocal t(6;13)(q21;q12) translocation. In an attempt to identify the presumed causative gene, we mapped the translocation breakpoints using fluorescence in situ hybridisation (FISH). Two overlapping genomic clones crossed the breakpoint on the der(6) chromosome, locating the breakpoint region between D6S1594 and D6S1250. Southern blot analysis allowed us to determine that the sorting nexin 3 gene (SNX3) was disrupted. Using Inverse PCR, we were able to amplify and sequence the der(6) breakpoint region, which exhibited homology to a BAC clone that contained marker D13S250. This clone allowed us to amplify and sequence the der(13) breakpoint region and to determine that no additional rearrangement was present at either breakpoint, nor was another gene disrupted on chromosome 13. Therefore, the translocation was balanced and SNX3 is probably the candidate gene for MMEP in the patient. However, mutation screening by dHPLC and Southern blot analysis of another sporadic case with MMEP failed to detect any point mutations or deletions in the SNX3 coding sequence. Considering the possibility of positional effect, another candidate gene in the vicinity of the der(6) chromosome breakpoint may be responsible for MMEP in the original patient or, just as likely, the MMEP phenotype in the two patients results from genetic heterogeneity.

Abnormalities, Multiple↗