A comparison of skeletal stability after mandibular advancement and use of two rigid internal fixation techniques.

PURPOSE: Two different methods of rigid fixation were compared for postoperative stability 6 months after mandibular advancement for treatment of Class II malocclusion. MATERIAL AND METHODS: Sixty (30 + 30) patients from two different oral and maxillofacial units treated for a Class II malocclusion by bilateral saggital split osteotomy (BSSO), and two different methods of internal rigid fixation were prospectively investigated. Two groups (S1, n = 15; S2, n = 15) had bicortical noncompressive screws inserted in the gonial area through a transcutaneous approach, and the other two groups (P1, n = 15; P2, n = 15) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively and 6 months after the operation. A computer program was used to superimpose the three cephalograms and to register the mandibular advancement and postoperative change both sagittally and vertically. RESULTS: These were minor differences in the advancement and postoperative changes between the four groups, but statistically no significant difference was shown in either sagittal or vertical directions. However, statistically verified differences proved that increasing age was associated with a smaller amount of postsurgical relapse. Low-angle cases (ML/NSL < 25 degrees) had a bigger amount of surgical (P = .0008) and postsurgical (P = .0195) movement compared with the patients in the high-angle group (ML/NSL < 38 degrees). Using a multiple regression test, a positive correlation was also shown between the amount of surgical advancement and the amount of postsurgical instability (P = .018). CONCLUSIONS: This prospective dual-center study indicates that the two different methods of internal rigid fixation after surgical advancement of the mandible by BSSO did not significantly differ from each other, and it is up to the individual operator to choose the method for internal rigid fixation.

Function of the masticatory system in 20 patients with mandibular hypo- or hyperplasia after correction by a sagittal split osteotomy.

Twenty patients with malocclusions were examined for signs and symptoms of craniomandibular disorders (CMD) before surgical correction of their anomalies. Such signs and symptoms were very common and were in many patients the main reason for requesting treatment. Eight patients had rigid and 12 non-rigid fixation. All patients were re-examined 1 year after surgery. This examination showed a statistically significant improvement of signs and symptoms of CMD but those who had had non-rigid fixation showed a statistically significant impairment in maximal mouth opening while no such change was noted in those treated with rigid fixation. Eight patients reported significant reduction of their recurrent headaches. It is concluded that surgical correction of malocclusion has a beneficial effect not only on the aesthetic appearance and dental occlusion but also on signs and symptoms of CMD.

CT-scanning in the preoperative planning of osseointegrated implants in the maxilla.

The preoperative use of computed tomography in the planning for osseointegrated implants in the maxilla is described. In addition to the image of the soft tissue and alveolar bone provided, this procedure makes the deduction of the ideal fixture site possible. This is done using information supplied by the CT scanning. It is a time-saving method compared to conventional tomography and eliminates the need for panoramic and intra-oral radiographs.

Changes in temporomandibular joint pain-dysfunction after surgical correction of dentofacial anomalies.

20 patients with dentofacial anomalies were investigated with respect to signs and symptoms of temporomandibular joint pain-dysfunction, which was a common reason for requesting treatment. After surgical correction of the malocclusions, the patients were re-examined 1 week after removal of intermaxillary fixation (IMF), 6 months after surgery and, finally, after 1 to 2 1/2 years. Several of the patients complained of recurrent headaches before surgery and also reported several other subjective symptoms of temporomandibular joint pain-dysfunction. At final control, a statistically significant reduction in headache frequency, as well as for the anamnestic dysfunction index as a whole, was noted. An impairment of clinical signs of temporomandibular joint pain-dysfunction was noted 1 week after removal of IMF, but the situation then returned to that found preoperatively. At final control, a statistically significant reduction of the clinical dysfunction index used was noted. In line with other previous investigations, the patients were satisfied with the aesthetic result of the treatment. A statistically significant increase in number of occluding pairs of teeth was recorded postoperatively and the patients reported an improvement of chewing ability. It is concluded that surgical correction of dentofacial anomalies has a beneficial effect not only on aesthetic and dental occlusion but also upon signs and symptoms of temporomandibular joint pain-dysfunction.

Sagittal split technique I. Immediate postoperative conditions. A radiographic follow-up study.

The postoperative appearance of 28 patients was studied following sagittal split osteotomy. A radiological evaluation of the direction and location of the split, secondary unwanted fractures and the area of overlap and contact relationship between the fragments was carried out. In 70% of the cases examined the line of cleavage broke through on the medial surface of the ramus. Unwanted fractures occurred in five of the 56 operated rami, however, these did not influence the postoperative healing to a great extent. The area of overlap between the fragments varied from 3-10 cm2. In some cases diastases of up to 8 mm were noted. The true area of contact as such was significantly less than the area of overlap.

Sagittal split technique. II. Radiographic findings during the fixation period. A radiographic follow-up study.

The radiological appearance of 28 patients following sagittal split osteotomy was studied during the fixation period. Larger areas of overlap and smaller diastasis between the fragments were more frequently associated with short periods of fixation (7 weeks or less). This difference was not statistically significant. In 84% of the operated sides varying degrees of decalcification could be seen within the bone structures. Using tomographic images callus formation between fragments could be registered in 75% of the cases before or at the termination of the fixation; these cases were all stable after removal of fixation. With the exception of two cases the remaining 25% were clinically stable, however, although callus formation could not be demonstrated radiographically.

Sagittal split technique. III. Postoperative rest conditions. A radiographic follow-up study.

The radiological appearance of 26 patients was studied 11--53 months postoperatively following sagittal split osteotomy. In 75% of the cases examined an increase in the mandibular angle could be noted compared to pretreatment values. This differences was statistically significant. In 70% of the cases the angle increased by 1--10 degrees. In 25% there was no change or reduction in the angle. The antero-posterior width of the rami was found to decrease; when this was combined with an increase in the mandibular angle, extensive morphological changes were found. These postoperative conditions must be regarded as unsatisfactory and a modification of the technique of sagittal split osteotomy should be considered as for example advocated by EPKER4.

"The sagittal aplitting technique" - a follow-up study.

In endeavoring to find a comprehensive method providing good treatment results in cases of mandibular prognathism, retrognathism and laterognathism, the sagittal splitting technique has been on trial in the Department of Oral Surgery in Boden since 1972. Experience gained from the first 12 operated cases is discussed from a clinical viewpoint. After a control period of 24-36 months, it was found that this method is to be preferred to that previously used in the Department, horizontal ramus osteotomy.

Nodular fascitis in the oral cavity.

Clinical and microscopic features of a deeply situated lesion of the oral buccal mucosa are reported. The lesion suddenly appeared as a small lump, without obvious cause. A histologically alarming picture gave rise to a preliminary diagnosis of a sarcoma. However, features of nodular fascities were subsequently recognized and following local removal there has been no recurrence in the 4 years that have elapsed since operation.