Stability after surgical-orthodontic correction of skeletal Class III malocclusion. 2. Maxillary advancement.

Nearly half the patients with skeletal Class III malocclusion have maxillary deficiency as the major component of their problem, and modern surgical techniques allow maxillary osteotomy to correct the deformity. Changes at surgery and postsurgically were studied in 49 patients who underwent isolated surgical maxillary advancement. Thirty-one had wire osteosynthesis and maxillomandibular fixation, and 18 had rigid fixation with bone plates. In nearly half the patients, the maxilla was moved down as well as forward, indicating that the patient had both vertical and anteroposterior deficiency. In the anteroposterior plane, 80% of the patients had excellent stability at 1 year, while 20% had 2 to 4 mm of posterior movement of anterior maxillary landmarks. There was no difference in anteroposterior stability between wire/maxillomandibular fixation and rigid internal fixation groups. When the maxilla was moved down as well as forward, there was a strong tendency for relapse upward in both fixation groups. As a result, the chin frequently became more prominent from immediate postsurgery to 1-year followup, as upward movement of the maxilla allowed the mandible to rotate upward and forward.     

Cephalometric changes after the correction of class III malocclusion with maxillary expansion/facemask therapy.

The purpose of this study was to analyze the cephalometric changes that occurred during and after the correction of Class III malocclusion. The records of 24 Class III patients treated with a banded expansion appliance and custom facemask were compared with 24 Class I and 27 Class III untreated controls. Cephalometric means were calculated for the annualized data and compared univariately with unpaired t tests to determine significant differences. Treatment results showed more convexity of the facial profile from anterior displacement and downward and backward rotation of the maxilla and clockwise rotation of the mandible. The maxillary teeth moved forward while the lower incisors retruded. Postprotraction results showed the maxilla did not relapse after treatment but grew anteriorly similar to the Class III controls but less than the Class I controls. Mandibular growth was similar for the treatment and control groups. Dental changes compensated for decreasing overjet whereas the soft tissue profile showed no significant posttreatment changes. Results in the intercontrol comparison showed the Class III controls had significantly less forward movement of A-point and greater forward movement of the mandible than Class I controls. Because of these differences using a Class I control group to compare to a Class III treatment group will tend to underestimate the treatment effects and overestimate posttreatment changes. Overcorrection of the Class III malocclusion is recommended to compensate for postprotraction growth deficiency of the maxilla.     

Measurement of tooth movement.

1. Tooth movement relative to the alveolar bone can be precisely described only by superimposing on fixed points in the bone. Implants are the best known way today. Over short-term studies laminagraphy and the use of bony trabeculations are also useful. Remodeling occurs extensively on bony surfaces, making them too labile for use as stable landmarks. To project small amounts of tooth movement based on the use of such methods is so questionable as to represent little better than a guess or a clinical impression. 2. Growth can be separated into vertical and anteroposterior vectors with respect to the dentition. Since the occlusion is the concern, orientation of vertical and anteroposterior vectors to the occlusal plane is a reasonable baseline. The vertical and anteroposterior dental changes may not show a linear relationship in the anterior and posterior parts of the mouth when jaw rotations are occurring. 3. Growth can be disproportionate in either the vertical and/or the anteroposteroir plane of space. If the vertical increments of the anterior face differ from the vertical increments at the posterior face, mandibular rotations occur. This growth is accompanied by dental compensations that tend to mask the rotation. Therefore, open bite and deep bite are frequently skeletal growth problems. 4. Disproportional forward growth of the maxilla or mandible in an anteroposterior direction can lead to Class II or III relations. The growth that leads to Class II or Class III is accompanied by dental migrations that tend to mask this disproportionate growth. Orthodontic treatment of growth disproportionalities usually represents attempts to make the teeth further compensate. If surgical options are elected, the dental compensations should be removed prior to surgery in order to achieve a full surgical correction. 5. The teeth tend to move and grow in the opposite direction of the growth disproportionality. The teeth tend to mask the disproportionality. Thus, in an open bite, the incisors tend to move vertically further than in deep bites. Vertical imbalances may be more difficult to mask. Backward rotation of the mandible requires more vertical movement at the incisor than at the molar just to maintain vertical incisor relationships.     

Characterization of phenotypes of skeletal Class III malocclusion in Korean adult patients treated with orthognathic surgery using cluster analysis

ObjectivesTo characterize the phenotypes of skeletal Class III malocclusion in adult patients who underwent orthognathic surgery (OGS).Materials and MethodsThe sample consisted of 326 patients with Class III malocclusion treated with OGS (170 men and 156 women; mean age, 22.2 years). Using lateral cephalograms taken at initial visits, 13 angular variables and one ratio cephalometric variable were measured. Using three representative variables obtained from principal components analysis (SNA, SNB, and Björk sum), K-means cluster analysis was performed to classify the phenotypes. Statistical analysis was conducted to characterize the differences in the cephalometric variables among the clusters.ResultsClass III phenotypes were classified into nine clusters from the following four major groups: (1) retrusive maxilla group, clusters 7 and 9 (7.1% and 5.5%; severely retrusive maxilla, normal mandible, severe and moderate hyperdivergent, respectively) and cluster 6 (9.2%; retrusive maxilla, normal mandible, normodivergent); (2) relatively protrusive mandible group, cluster 2 (20.9%; normal maxilla, normal mandible, hyperdivergent); (3) protrusive mandible group, clusters 3 and 1 (11.7% and 15.3%; normal maxilla, protrusive mandible, normodivergent and hyperdivergent, respectively) and clusters 8 and 4 (15.3% and 3.7%; normal maxilla, severe protrusive mandible, normodivergent and hypodivergent, respectively); and (4) protrusive maxilla and protrusive mandible group, cluster 5 (11.4%; protrusive maxilla, severely protrusive mandible, normodivergent). Considerations for presurgical orthodontic treatment and OGS planning were proposed based on the Class III phenotypes.ConclusionsBecause the anteroposterior position of the maxilla and rotation of the mandible by a patient''s vertical pattern determine Class III phenotypes, these variables should be considered in diagnosis and treatment planning for patients who have skeletal Class III malocclusion.     

Stability of skeletal class III malocclusion after combined maxillary and mandibular procedures: rigid internal fixation versus wire osteosynthesis of the mandible.

PURPOSE: The aim of this study was to evaluate skeletal stability after double-jaw surgery for correction of skeletal Class III malocclusion to assess whether there were any differences between wire and rigid fixation of the mandible. PATIENTS AND METHODS: Thirty-seven Class III patients had Le Fort I osteotomy stabilized with plate and screws for maxillary advancement. Bilateral sagittal split osteotomy for mandibular setback was stabilized with wire osteosynthesis and maxillomandibular fixation for 6 weeks in 20 patients (group 1) and with rigid internal fixation in 17 patients (group 2). Lateral cephalograms were taken before surgery, immediately after surgery, 8 weeks after surgery, and 1 year after surgery. RESULTS: Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. One year after surgery, maxillary sagittal stability was excellent in both groups, and bilateral sagittal split osteotomy accounted for most of the total horizontal relapse observed. In group 1, significant correlations were found between maxillary advancement and relapse at the posterior maxilla and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. In group 2, significant correlations were found between mandibular setback and intraoperative clockwise rotation of the ramus and between mandibular setback and postoperative counterclockwise rotation of the ramus and mandibular relapse. No significant differences in postoperative skeletal and dental stability between groups were observed except for maxillary posterior vertical position. CONCLUSIONS: Surgical correction of Class III malocclusion after combined maxillary and mandibular procedures appears to be a fairly stable procedure independent of the type of fixation used to stabilize the mandible.     

Skeletal stability following maxillary impaction and mandibular advancement

The purpose of this study was to retrospectively evaluate the stability of combined Le Fort I maxillary impaction and mandibular advancement performed for the correction of skeletal Class II malocclusion. Twenty-nine patients, mean age 22.6 years, underwent bimaxillary surgery with rigid internal fixation. Standardised cephalometric analyses were performed using serial lateral cephalometric radiographs. The post-surgical follow-up was a minimum of 12 months, with a mean of 25.2 months. The maxilla was impacted by a mean of 4.3 +/- 3.3 mm, and horizontally advanced by a mean of 2.6 +/- 2.3 mm. The results demonstrated that the maxilla tended to move anteriorly and inferiorly but this was not significant in either horizontal or vertical planes (P > 0.05). The mean advancement of the mandible, at menton, was 10.7 +/- 5.6 mm, and in 14 cases (48.2%) menton was advanced greater than 10 mm. In 34.7% of the patients the mandible underwent posterior movement between 2 and 4 mm. In the vertical plane, gonion moved superiorly by a mean of 2.7 +/- 3.6 mm which was significant. Significant mandibular relapse was found to have occurred in five female patients, with high mandibular plane angles who had undergone large advancements of greater than 10 mm. In conclusion, the majority of patients undergoing bimaxillary surgery for the correction of skeletal Class II malocclusions maintained a stable result. However, a small number of patients, exhibiting similar characteristics, suffered significant skeletal relapse in the mandible secondary to condylar remodelling and/or resorption.     

Management of the Class III malocclusion treated with maxillary expansion,facemask therapy and corrective orthodontic. A 15-year follow-up

The facial growth of Class III malocclusion worsens with age, in this case, the early orthopedic treatment, providing facial balance, modifying the maxillofacial growth and development. A 7.6-year old boy presented with Class III malocclusion associated with anterior crossbite; the mandible was shifted to the right and the maxilla had a transversal deficiency. Rapid maxillary expansion followed by facemask therapy was performed, to correct the anteroposterior relationship and improve the facial profile. The patient was followed for a 15-year period, after completion of the treatment, and stability was observed. Growing patients should be monitored following their treatment, so as to prevent malocclusion relapse.     

A three-dimensional soft tissue analysis of 16 skeletal class III patients following bimaxillary surgery.

A three-dimensional soft tissue study of the results of surgery in a group of 16 skeletal Class III adult patients following orthognathic surgery was carried out using laser scans (Arridge et al., 1985). The patient group was compared to a control group of the same population. Laser scans were taken prior to surgery, 3 months post-surgery, and at least 1 year after retention. Preoperative comparison to the control groups revealed that the facial disproportion related to both the maxilla and the mandible. Le Fort I advancements resulted in broadening of the lateral aspects of the nose, advancement of the dorsum, and overcorrection of the alar bases. There was a degree of change over the cheeks bilaterally, because of alterations in the general drape of the soft tissues. There was a degree of overcorrection in the female group following mandibular set back but the male group were still more prognathic, when compared to the control group. There was a marked degree of relapse in the mandible from 3 months to 1 year postoperatively, with a resultant anterior movement of the maxillary arch. Laser scanning has proved to be a simple non-invasive method of measuring three-dimensionally, and is a very useful tool in auditing surgical outcome and measuring surgical relapse.     

Maxillary protraction and chincap appliance treatment effects and long-term changes in skeletal class III patients

The purpose of this study was to investigate the orthopedic effects of combined maxillary protraction appliance (MPA) and chincap therapy on growing Japanese girls and the posttreatment changes after growth is complete. To estimate the actual effects of treatment and posttreatment changes, we used a series of templates that had been constructed from semilongitudinal data of Japanese girls with normal occlusion. During treatment, forward movement of the maxilla with counterclockwise rotation, and backward and downward movement of the mandible with clockwise rotation and growth retardation were observed. The forward movement of the maxilla persisted until growth was complete. During the posttreatment period, the mandible maintained its improved position but showed excessive growth, which could be a rebound change. These results indicate that combined MPA and chincap treatment is effective for correcting skeletal Class III malocclusion.     

Postsurgical changes of mandible based on vertical dimension increase in Skeletal Class III deformities

The aim of this study was to evaluate the postsurgical mandibular changes after surgery based on vertical dimension increase in skeletal Class III deformities.Patients who underwent mandibular setback surgery for skeletal Class III malocclusion correction with surgery-first orthognathic treatment were enrolled in the study. Lateral cephalograms were obtained at initial visit, immediately after surgery, 6 months after surgery, and at post-treatment. Postsurgical change of the mandible based on the vertical dimension increase was estimated using a diagrammatic method before surgery and this amount was compared with the actual amount of mandibular forward movement at 6 months after the surgery, using a paired t-test and Bland–Altman plot.Thirty patients (16 men and 14 women; mean age, 22.6 years) with skeletal Class III deformities had undergone mandibular setback surgery with the surgery-first orthognathic treatment. Immediately after surgery, the mandible setback was 9.4 ± 3.7 mm at pogonion. Six months after surgery, the mandible moved forward at an average of 2.3 ± 1.5 mm which corresponded to the estimated value of 2.2 ± 0.9 mm. The estimated amount of postsurgical movement did not show a statistically significant difference from the actual value on paired t-test (p = 0.349). The Bland–Altman analysis showed that the difference between the two values was within the limits of agreement.The postsurgical changes based on vertical dimension increase in surgery-first orthognathic treatment might be predicted by using a diagrammatic method.     

Relapse patterns of two-jaw surgical correction in patients with skeletal Class III malocclusion and different vertical facial types

The aim of this study was to evaluate postoperative relapse after the surgical correction of skeletal Class III deformities of various facial patterns as a guide to surgical planning. A retrospective cohort study of 90 consecutive patients with skeletal Class III malocclusion who underwent bimaxillary surgery was performed. The surgical outcomes and postoperative stability were compared. The primary predictor variable was vertical facial type, which was classified into three groups according to the Frankfort mandibular plane angle (FMA). The primary outcome of angular and linear measurements was obtained using serial cone beam computed tomography scans obtained at time points of preoperative, 1 week after surgery, and orthodontic debonding. No significant difference in skeletal relapse was observed in patients with the different vertical facial types. The mandible displayed a forward and upward relapse in all three groups postoperatively. The patients with a low FMA exhibited a more consistent mandibular relapse pattern than those with a normal or high FMA. These findings suggest that bimaxillary surgery is clinically stable for mandibular prognathism regardless of the vertical facial pattern. However, 1–1.5 mm of overcorrection in the mandible setback should be considered in patients with a low FMA, because of the greater facial depth and consistent forward and upward mandibular relapse pattern.     

Superior repositioning of the maxilla combined with mandibular advancement: mandibular RIF improves stability.

Postsurgical changes in 24 patients who had rigid internal fixation (RIF) of the mandible with screws after combined superior repositioning of the maxilla and mandibular advancement were compared with 53 patients who underwent the same surgery but who had intraosseous wire fixation, skeletal suspension wires, and 8 weeks of maxillomandibular fixation (MMF). During the first 8 weeks after surgery, the mean posterior relapse of the mandible was greater in the MMF group than in the RIF group (for example, -1.1 mm versus 0.15 mm at B point), and the percentage of patients with clinically significant vertical and horizontal changes was greater in the MMF group. By 1 year, there had been slight additional mean relapse in the MMF group (-1.5 mm net relapse at B point, with 42% of the patients showing 2 mm or more relapse). In the RIF group, the mandible was more likely to be repositioned forward than posteriorly (net mean change at B point, 0.7 mm forward; 33% had 2 mm or more forward movement). In the RIF group, all but one of the patients (96%) were judged to have an excellent clinical result; in the MMF group, the corresponding figure was 60%.     

Morphometric analysis of treatment effects of bone-anchored maxillary protraction in growing Class III patients

The aim of the present morphometric investigation was to evaluate the effects of bone-anchored maxillary protraction (BAMP) in the treatment of growing patients with Class III malocclusion. The shape and size changes in the craniofacial configuration of a sample of 26 children with Class III malocclusions consecutively treated with the BAMP protocol were compared with a matched sample of 15 children with untreated Class III malocclusions. All subjects in the two groups were at a prepubertal stage of skeletal development at time of first observation. Average duration of treatment was 14 months. Significant treatment-induced modifications involved both the maxilla and the mandible. The most evident deformation consisted of marked forward displacement of the maxillary complex with more moderate favourable effects in the mandible. Deformations in the vertical dimension were not detected. The significant deformations were associated with significant differences in size in the group treated with the BAMP protocol.     

Combined orthodontic-surgical correction of moderate mandibular deficiency.

Carefully planned, coordinated, and executed orthodontic and surgical treatment is a viable alternative to traditional orthodontic treatment of patients with moderate mandibular deficiency. Recognition of their clinical manifestations is essential to distinguish between relative and absolute mandibular deficiency. If after clinical analysis of the Class II patient, esthetic priorities are established to maintain a balanced relationship between the upper lip and nose and not reduce the prominence of the upper lip, mandibular deficiency must be treated by surgical advancement of the mandible, superior repositioning of the maxilla, and consequent autorotational movement of the mandible forward and upward, or a combination of these procedures. The common denominator of successful therapy of absolute mandibular deficiency involves surgery to advance the mandible; relative mandibular deficiency, on the other hand, is treated by maxillary surgery to reposition the maxilla superiorly to allow forward and upward movement of the retropositioned mandible (autorotation). In actual clinical practice many patients manifest a combination of absolute and relative mandibular deficiency and are treated by maxillary and mandibular surgery. Lateral maxillary osteotomies, in concert with rapid maxillary expansion and genioplasty to alter the dimensions of the chin, are essential adjunctive surgical procedures to achieve three-dimensional esthetic and occlusal balance.     

Treatment effect of combined maxillary protraction and chincap appliance in severe skeletal Class III cases

The present study was designed to evaluate the true treatment effects of the maxillary protracting appliance with chincap for skeletal Class III cases and to evaluate the difference of true treatment effects between the cases in which the maxilla was protracted from the first molars and the cases protracted from the first premolars. Cephalograms of 63 cases (the first molar protraction group--27 cases protracted from the first molars, the first premolar protraction group--36 cases protracted from the first premolars) treated with the combined maxillary protraction and chincap appliance were used. Template analysis was performed to evaluate the estimated treatment effects without growth change. Forward movement of the maxilla and backward rotation of the mandible were characteristic features of the estimated treatment effects in 63 cases. In comparing the two groups, the maxilla was displaced more anteriorly and rotated more upward and forward in the first molar protraction group. Therefore, the intraoral site of protraction should be selected by considering vertical dimensions of skeletal and dental structures, and the amount of forward displacement of the maxilla required in the treatment of the individual patient.     

Orthopedic/orthodontic treatment of a Class I malocclusion with a Class III skeletal pattern and maxillary deficiency. An American Board of Orthodontics case report

A case report of a Class I dental malocclusion superimposed on a Class III skeletal pattern with normal mandible and underdeveloped maxilla is presented. The patient was a 15-year-old girl whose statural growth was complete. The maxilla was deficient in anteroposterior and transverse dimensions, causing a slightly concave profile, a crossbite relationship of most of the anterior and posterior teeth, and upper anterior crowding. Sutural expansion and orthopedic advancement of the maxilla was used to reduce the maxillary deficiency. A complete 0.018-inch slot straight-wire appliance was used to align the teeth, close lower spaces, and detail the occlusion.     

上颌前牵引联合快速扩弓矫治儿童骨性Ⅲ类错前后软硬组织变化

目的:探讨上颌前牵引联合快速扩弓对儿童骨性Ⅲ类错的矫治效果。方法:对28例儿童骨性Ⅲ类错病人(7～10岁)进行上颌前牵引治疗,在前牵引前快速扩弓1周。分别在治疗开始(T0)和结束(T1)时拍摄头颅定位侧位片,进行定点测量分析。结果:①硬组织变化:ANB角增加5.37°(P<0.05),Wit’s值增加5.74 mm(P<0.05),Ptm-A增加2.49 mm(P<0.05),Yaxis增加1.82°(P<0.05);SNB角减小0.75°(P>0.05),Go-Me、Co-Gn分别增加0.64 mm、2.21 mm,但P>0.05,SN-PP减小0.61°(P>0.05),PP-MP增加5.54°(P<0.05),下面高、下面高/全面高分别增加3.98(P<0.05)、1.61(P>0.05);U1-NA角增加3.10°(P<0.05),L1-NB角减小1.23°(P<0.05),Ms6-PP距增加1.13 mm(P<0.05);②软组织测量项目变化:面型角增大5.98°,颏唇角减小2.45°、H角增大5.2°,上唇-E线距增大1.42 mm,下唇-E线距减小1.18 mm(P<0.05)。结论:前牵引联合快速扩弓矫治儿童骨性Ⅲ类错,可产生显著治疗效果,能促进上颌骨的生长,使面型改善,但下颌出现顺时针旋转,高角病人慎用。     

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.     

Skeletal Class III Malocclusion with Unilateral Congenitally Missing Maxillary Incisor Treated by Maxillary Protractor and Edgewise Appliances

This case report describes the orthodontic treatment of a 10-year-old female patient with a combination of Angle Class III malocclusion, a missing maxillary right lateral incisor, a supernumerary tooth with a short root on the lingual side of the maxillary incisor, a skeletal Class III jaw base relationship caused by a diminutive maxilla, and retroposition of the maxilla. We chose to close the space of the missing tooth, as well as the space created by extraction of the maxillary lateral incisor, by forward movement of the canine and premolars using a maxillary protractor with edgewise appliances. As a result, both the maxillary premolars and the molars were moved mesially, and a Class II molar relationship with tight interdigitation was achieved. Our results suggest that the combination of maxillary protractor and nontorque brackets was effective not only for correcting skeletal Class III malocclusion, but also for forward movement of the maxillary posterior teeth.     

Effect of protraction headgear on Class III malocclusion.

Ten patients with skeletal Class III malocclusion in the early mixed dentition who were treated with maxillary expansion appliance and protraction headgear were compared with reasonably matched controls. Significant orthopedic effects were found after as little as 6 months of treatment. Cephalometric analysis revealed that the correction of Class III malocclusion was primarily a result of forward and downward movement of the maxilla and backward rotation of the mandible. The clinical result of one patient treated with this appliance is used to demonstrate the importance of force magnitudes and directions, as well as the design of the appliance, to the success of the treatment.