Stability after surgical-orthodontic correction of skeletal Class III malocclusion. I. Mandibular setback

Postsurgical stability of mandibular setback to correct mandibular prognathism was compared for three approaches: transoral vertical ramus osteotomy, bilateral sagittal split osteotomy with wire osteosynthesis and maxillomandibular fixation, and bilateral sagittal split osteotomy with rigid internal fixation via bone screws. In the transoral vertical ramus osteotomy group, the mean postsurgical change in chin position was almost zero, but nearly 50% of the patients did have clinically significant changes in chin position; two thirds of these movements were posterior and one third anterior. In the bilateral sagittal split osteotomy groups, the chin either stayed in its immediately postsurgical position or moved anteriorly. In one fourth of the patients who received maxillomandibular fixation and in nearly half of the patients who received rigid internal fixation, the chin moved forward more than 4 mm.     

Stability after surgical-orthodontic corrective of skeletal Class III malocclusion. 3. Combined maxillary and mandibular procedures

Stability after combined Le Fort I and bilateral sagittal split osteotomies was reviewed in 51 patients with skeletal Class III malocclusion. Because vertical changes in the position of the maxilla affect both the vertical and anteroposterior positions of the mandible, the sample was subdivided by the direction of vertical movement of the maxilla at surgery. Excellent postsurgical stability was observed in the long-face Class III patients in whom upward and forward movement of the maxilla was combined with ramus osteotomy to prevent excessive forward rotation of the mandible. When the maxilla was moved forward and the mandible set back with minimal vertical change, moderate relapse tendencies were observed in both jaws, but most of the correction was maintained at 1 year. When the maxilla was moved down and forward while the mandible was set back, moderate vertical relapse of the maxilla and anteroposterior relapse of the mandible followed. Stability of the downward movement of the maxilla was, on average, better than that resulting from maxillary surgery alone.     

Long-term skeletal and profile stability after surgical-orthodontic treatment of Class II and Class III malocclusion

ObjectiveThe purpose of this perspective research was to study the long-term stability of skeletal, dentoalveolar and soft tissue after orthognathic surgery in subjects presenting with Class II and Class III malocclusions.MethodsThe available digitized cephalometric radiographs, including pretreatment (t₀), presurgery (t₁), a minimum of 12 months postsurgery (t₂) and at least 3 years after the orthosurgery treatment (t₃) were taken between 1998 and 2010. In Group 1 mandibular advancement and in Group 2 mandibular advancement and maxillary impaction surgery were performed for correction of Class II. In Group 3 maxillary advancement and in Group 4 surgical maxillary advancement with mandibular setback, for correction of Class III.ResultsIn all the phases mandibular length was shorter in Group 1, and the inferior third of the face was longer in Group 2. Before the surgery there was greater maxillary deficiency in Group 3 than Group 4 and mandibular length was longer in Group 4.ConclusionIn Groups 1 and 2, at retention phase, relapse occurred due to the increase in mandibular plane, whereas the surgeries performed in Groups 3 and 4 remained stable.     

Satisfaction of patients following surgical-orthodontic correction of skeletal Class III malocclusions

To assess whether patients were satisfied with the results of treatment, questionnaires were sent to 65 patients who had undergone either the extraoral curved oblique osteotomy or the sagittal split osteotomy for correction of skeletal Class III malocclusions. Seventy-eight per cent of the patients answered that they were satisfied with the results in regard to their chief problems and 75% had improved masticatory function. A favorable change in appearance was recognized by 33 patients, whereas 30 patients noticed no major changes. Factors affecting satisfaction with the results are discussed.     

Early correction of a developing skeletal Class III malocclusion

This case report describes the treatment of a Japanese girl aged 11 years 10 months who had a severe Class III malocclusion with a concave facial profile. She presented hypodivergent skeletal pattern with a -4.0-mm anterior crossbite and a deep overbite. She also had facial asymmetry attributed partly to the lateral mandibular shift to avoid incisal interferences. The treatment plan included a monoblock appliance, rapid palatal expansion, and fixed edgewise appliances at the final stage. The monoblock appliance was used to redirect the growth of the mandible to a clockwise direction and simultaneously correct the incisal relationships along with fixed edgewise appliances. Good incisal relationships were achieved, and facial esthetics was greatly improved after 28 months of treatment. Stability of the treatment result was excellent in the 3-year 9-month follow-up at the age of 18.     

Nasal changes after surgical correction of skeletal Class III malocclusion in Koreans

OBJECTIVE: To quantify the changes in the nose after bimaxillary surgery to correct skeletal Class III malocclusion and to test the hypothesis that there is no change in the nasal width following bimaxillary surgical correction of skeletal Class III when a nasal cinch is properly used. MATERIALS AND METHODS: Sixty-five adult Korean skeletal Class III patients who had received maxillary advancement/impaction and mandibular set-back surgery in conjunction with an alar base cinch suture were evaluated. The anthropometric variables of the nasal region were measured directly on the soft-tissue surface before and 6 months after surgery. RESULTS: After surgery, the alar width and alar base width had increased significantly (P < .001), while the nasal tip projection decreased (P < .001). The nostril morphology also showed widening (P < .001). There was a trend for females with a narrow alar width presurgically to have a larger amount of nasal widening compared with those with a broader alar width (P < .05). CONCLUSION: There is a high probability of nasal and nostril widening after bimaxillary surgery for skeletal Class III malocclusion in Koreans despite the careful performance of alar cinch suture. Nevertheless, the authors believe that alar cinch suture was positive in limiting the nasal widening to the minimum and would consider routine application during bimaxillary surgery for skeletal Class III especially for female patients with a narrow nose who are susceptible to these changes.     

Stability of skeletal Class III malocclusion after combined maxillary and mandibular procedures

The aim of this study was to evaluate the skeletal stability and time course of postoperative changes after surgical correction of skeletal Class III malocclusion. Combined maxillary and mandibular procedures were performed in 40 consecutive patients. Bilateral sagittal split osteotomy stabilized with wire osteosynthesis for mandibular setback and low-level Le Fort I osteotomy stabilized with plates and screws for maxillary advancement were performed. Maxillomandibular fixation (MMF) was in place for 6 weeks. Lateral cephalograms were taken before surgery, immediately postoperatively, 8 weeks after surgery, and 1 year postoperatively. Patients were divided into 2 groups according to vertical maxillary movement at surgery: a maxilla-up group with upward movement of the posterior nasal spine of 2 mm or more (group 1, n = 22), and a minimal vertical change group with less than 2 mm of vertical repositioning (group 2, n = 18). The results indicate that surgical correction of Class III malocclusion with combined maxillary and mandibular osteotomies appears to be fairly stable. One year postsurgery, maxillary stability was excellent, with a mean horizontal relapse at point A that represented 10.7% of maxillary advancement in group 1 and 13.4% in group 2. In the vertical plane, maxillary stability was also excellent, with a mean of 0.18 mm of superior repositioning at point A for group 1 and 1.19 mm for group 2. The mandible relapsed a mean of 2.97 mm horizontally at pogonion in group 1 (62% of mandibular setback) and 3.41 mm (49.7% of setback) in group 2. Bilateral sagittal split osteotomy with wire osteosynthesis and MMF was not as stable as maxillary advancement and accounted for most of the total horizontal relapse (almost 85%) observed. A trend to relapse was observed for maxillary advancement greater than 6 mm, while the single variable accounting for mandibular relapse in group 1 was the amount of surgical setback. Clockwise rotation of the ascending ramus at surgery was not correlated with mandibular relapse in relation to the type of fixation performed and therefore does not seem to be responsible for relapse.     

Patient satisfaction following orthognathic surgical correction of skeletal Class III malocclusion

The objectives of this study were to evaluate the relationship between preoperative psychologic status and attitude and postsurgical adjustment and experience of the surgical treatment. Questionnaires were sent to 140 consecutive Chinese patients with skeletal Class III malocclusion who had been treated with a combined orthodontic-surgical approach. The results showed the following: (1) immediately after the surgery 44% of patients had more pain, 57% had more numbness, and 73% had more swelling than expected; (2) most patients underwent noted marked changes in facial appearance (96%) and dental appearance (91%); (3) chewing ability improved in 71% of patients; (4) half of those with temporomandibular joint problems preoperatively experienced improvement; (5) personality and lifestyle were affected positively in about 50% of patients; (6) satisfaction with the treatment increased with time: 87% at 6 months and 92% at 24 months; and (7) a few patients (8%) regretted having undergone surgery, mainly because facial changes were not apparent. The vast majority of the present Chinese skeletal Class III patients were satisfied with the overall outcome of the continued orthodontic-surgical treatment.     

Stability of the mandible after surgical correction of skeletal class III malocclusion in 50 patients.

Fifty cases of skeletal Class III malocclusion were analyzed by the tracings of presurgical and postsurgical cephalograms to evaluate the stability of the mandible a year after surgery. In 33 patients, the curved oblique osteotomy in the ascending ramus was used; the correction was made in the mandibular body for 17 patients by either the rectangular osteotomy or the sliding osteotomy. Minimal relapse was observed in all three procedures, with the least amount occurring after mandibular body ostectomy or osteotomy. The results were considered to be due to careful determination of the correct time for surgery in each patient to avoid skeletal relapse resulting in continued mandibular growth, prompt osseous healing at the surgical sites by providing close and tight bony contact between the segments, elimination of the effect of the major muscles of mastication, minimum alteration in the position of the posterior segment and trimming of the margin of the anterior segment to form a proper gonial angle, and a stable occlusion with maximum intercuspation and an adequate overbite. In addition, preoperative orthodontic treatment and extraoral traction of the mandible by chin cups were considered effective means to stabilize the post-operative occlusion.     

Changes in soft tissue profile after surgical correction of skeletal class III malocclusion.

Cephalometric analysis of the facial soft tissue profile after surgical correction of skeletal Class III malocclusion performed either in the ascending ramus or in the mandibular body in 33 patients showed a close correlation between the horizontal movements of the soft tissue landmarks and those of the underlying skeletal and dental structures. In the vertical direction, the changes were more variable. A comparison of these results with the soft tissue profile of normal persons indicated that a natural appearance could be achieved after correction of Class III malocclusion by combined surgery and orthodontic treatment.     

Morphological parameters as predictors of successful correction of Class III malocclusion.

The aim of the study was to assess pre-treatment cephalometric parameters and measurements of the size of the apical bases as predictors of successful orthodontic correction of Class III malocclusions. Pre- and post-treatment lateral cephalograms and study models of 80 completed Class III subjects were examined to obtain 23 cephalometric parameters taken mainly from the analyses of McNamara and Schwarz, and to measure the size of the apical bases. Success of occlusal correction was evaluated as the percentage change of peer assessment rating score during treatment, which was used as the dependent variable in multivariate statistical analyses testing the predictive value of the parameters assessed. No improvement in the Class III skeletal pattern occurred during treatment and the treatment effects were confined to dentoalveolar changes. With the exception of the percentage midfacial length/mandibular length ratio, the net sum of maxillary and mandibular length differences, the mandibular ramus height/mandibular body length ratio and the gonion angle, most cephalometric parameters of pre-treatment craniofacial morphology assessed were poor predictors of successful correction of Class III malocclusions. Assessment of the size relationship of the maxillary and mandibular apical bases was the strongest predictor of occlusal correction achieved and may serve as a valuable diagnostic addition in the prediction of successful treatment outcome.     

Stability of maxillary advancement for correction of skeletal Class III malocclusion after combined maxillary and mandibular procedures: preliminary results of an active control equivalence trial for semirigid and rigid fixation of the maxilla

In this paper preliminary results are presented of a prospective study designed to examine the effect of maxillary fixation methods on postoperative stability. The purpose of this study was to evaluate the stability of Le Fort I osteotomy stabilized with semirigid fixation of the maxilla (SRMF) or rigid fixation of the maxilla (RMF). All patients had skeletal Class III malocclusion and underwent bimaxillary surgery (Le Fort I maxillary advancement with or without superior repositioning and bilateral sagittal split osteotomies of the mandible). Standardized cephalometric analysis was performed on serial radiographs of 42 patients immediately before surgery, 1 week after surgery, after release of fixation, and 1 year postoperatively. The patients were randomized into 2 treatment groups: 23 patients received RMF (group A), and 19 patients received SRMF (group B). Within the groups, patients showed good stability with regard to their baseline characteristics. To show the therapeutic equivalence of the 2 treatments, analysis of the recorded data followed the approach for an equivalence trial. The mean surgical advancement was 5.34 +/- 1.50 mm for group A and 4.51 +/- 1.37 mm for group B. The mean amount of postsurgical relapse was 0.98 +/- 1.27 mm for group A and 0.30 +/- 1.04 mm for group B. Group A patients experienced 93% of their relapse (0.92 mm) during fixation, while group B patients experienced 96% of their relapse (0.29 mm) after release of fixation. RMF provided better stability than SRMF for all maxillary landmarks in the vertical plane. All considered points both in horizontal and vertical plane exhibited full equivalence for 95% confidence intervals, which seems to indicate equivalent stability between the surgical procedures.     

Surgical-orthodontic correction of open bite accompanied with Class III malocclusion

In a patient with a long face, skeletal open bite and excessive mandibular body length, it was found that the sagittal split ramus osteotomy to close the open bite was unstable, when the lower jaw alone was a moved surgically to correct the open bite and progenie. There was a slight relapse of the open bite and lingual compensation of the upper incisors, which may have been due to tissue rebound during the retention period.