Maxillary Cant Research Articles

Orthognathic Considerations of Maxillary and Mandibular Asymmetry at Skeletal Maturity in Patients with Cleft Lip and Palate.

Improving occlusion and aesthetics is the primary objective of orthognathic surgery for patients with cleft lip and palate (CLP). However, these patients often suffer from horizontal, vertical, and rotational asymmetry in addition to maxillary retrusion. This study aims to describe maxillary and mandibular asymmetry in patients with CLP undergoing orthognathic surgery and analyze its anatomic basis. Patients with isolated CLP undergoing CT imaging prior to orthognathic surgery were retrospectively reviewed. Maxillary and mandibular positioning and dimensional symmetry were evaluated. Incidence of clinically significant asymmetry, correlations between areas of asymmetry, and associations with clinical history were analyzed. Fifty-eight patients, with mean age 17 years were analyzed, including 32 patients with unilateral CLP and 26 with bilateral CLP. Twenty (34%) patients demonstrated chin deviation ≥4mm and 21 (36%) had a ≥5% discrepancy in mandibular ramus lengths. Horizontal occlusal plane cant of ≥2° was seen in 20 (34%) maxillae and 28 (48%) mandibles, with dental arch yaw ≥2° noted in 32 (55%) of both maxillae and mandibles. Chin deviation correlated with maxillary cant, discrepancy in ramus length, discrepancy in mandibular body length, and discrepancy in condylar volume (p<0.05). Bilateral and unilateral CLP did not show significantly different asymmetry on any measure (p>0.05). Both maxillary and mandibular asymmetry is common in skeletally mature patients with CLP and frequently results in notable chin deviation. Preoperative three-dimensional imaging and virtual surgical planning of orthognathic surgery aid in recognition of facial asymmetries and reveal opportunities to optimize results in this population.

Simultaneous standard total joint prosthesis reconstruction with SSRO and Le Fort I osteotomy in the treatment of unilateral temporomandibular joint ankylosis with jaw deformity: a case cohort study.

Unilateral temporomandibular joint ankylosis with jaw deformity (UTMJAJD) may require simultaneous total joint prosthesis (TJP) reconstruction, sagittal split ramus (SSRO), and Le Fort I osteotomies. The purpose of this study was to evaluate outcomes in patients treated with these procedures. Patients diagnosed UTMJAJD between 2016 and 2018 were selected for the study. Mandible-first procedure was performed after ankylosis release with TJP on the ankylosed side and SSRO on the contralateral side. Le Fort I osteotomy with and without genioplasty was lastly performed. Maximal incisor opening (MIO), facial symmetry, and jaw and condyle stability were compared before, after operation, and during follow-ups. Seven patients were included in the study. Their average chin deviation was 9.5 ± 4.2mm, and maxillary cant was 5.1 ± 3.0°. After operation, jaw deformity significantly improved, with chin deviation corrected 7.6 ± 4.1mm (p = 0.015) and advanced 5.9 ± 2.5mm (p = 0.006). After an average follow-up of 26.6 ± 17.1months, MIO significantly increased from 11.4 ± 9.3 to 35.7 ± 2.6mm (p = 0.000). The occlusion was stable with no significant positional or rotational changes of the jaw (p > 0.05). There was no obvious condylar resorption during follow-ups. Simultaneous TJP reconstruction, SSRO, and Le Fort I osteotomy are reliable and effective methods for the treatment of UTMJAJD.

Which Skeletal Factors Can Affect Lip Canting in Facial Asymmetry?: Statistical Analysis.

Lip canting, which is a noticeable factor in patients with facial asymmetry, can be influenced by the dentofacial skeleton. During orthognathic surgery, postoperative changes in facial soft tissue occur along the newly positioned hard tissue. Therefore, the evaluation of soft tissue before surgery is important. The purpose of this study was to investigate the skeletal factors that can affect lip canting by statistically comparing 2 facial horizontal planes using a three-dimensional reconstruction model. The findings of the present study showed a statistical correlation between lip canting and 3 skeletal factors: menton deviation, maxillary canting, and ramal length differences. Furthermore, a statistical correlation was identified between the Frankfort Horizontal plane and the intercanthal plane compared with the lip canting line. This result suggests that the intercanthal plane could be a standard horizontal plane in three-dimensional reconstruction model analysis.

Perception of discrepancy in the upper midline position in conjunction with the gingival display according to various occupations in Iran.

This study evaluated the influence of various gingival displays on the esthetic perception in the presence of upper dental midline discrepancy. A smiling image of a male subject was altered digitally to produce five image series: normal smile (series A), decreased tooth show (series B), increased gingival show (series C), maxillary cant (series D), and asymmetric upper lip elevation (series E). In each image series, the midline was deviated to the right and left incrementally. A total of 210 raters (four professional groups and laypersons, n = 42 in each group) determined the midline deviation threshold and the attractiveness of midline position in each series. The right and left thresholds were statistically similar for the symmetrical series (A, B, and C), while for series D, the right threshold was significantly lower. In most rater groups, the mean threshold order was: B > A > E > C > D. In all the series, the raters selected the coincident midline as the most attractive series except for series D, for which 1-2-mm deviations to the left were selected as the most attractive by almost all the groups. It is crucial to establish the coincident midline position in a symmetrical smile, especially when a gummy smile exists. In the asymmetrical gingival show, a coincident midline might not be the most esthetic midline position.

Relationship between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

Introduction. Maxillary sinus hypoplasia (MSH) has been reported to cause a cant in the orbital plane. No similar reports exist about the possible impact on the maxilla. The aim of this study was to assess if MSH is associated with maxillary occlusal plane (MOP) cant and if dental or mandibular factors influenced the existence of the MOP cant. Methods. 80 cone beam CT images of subjects with MSH were analyzed for the type of MSH, degree of MOP cant, open or cross bite, mandibular asymmetry, and degenerative joint disease of the temporomandibular joints. The subjects were compared with a control group matched by age and gender. Results. The degree of MOP cant (range 0–5.1°) was not statistically significantly different in unilateral vs. bilateral MSH or between the different types of MSH. The frequency of open bite, crossbite, mandibular asymmetry, or degenerative joint disease in unilateral vs. bilateral MSH or between the different types of MSH was not statistically significantly different. Between the case and control, there was no statistically significant difference in the degree of MOP cant ( 1.3 ± 1.1 ° vs. 1.1 ± 0.9 ° , respectively) or frequency of dental and mandibular factors. There was low positive linear correlation between MOP cant and mandibular symmetry in MSH subjects (Spearman’s rho = 0.23 ) and controls (Spearman’s rho = 0.18 7). Conclusions. The data suggests a view of the alveolar bone as the adaptable skeletal unit to ensure and bridge the functionality between the nasomaxillary complex and TMJ system–two systems with very different function, and therefore largely independent “matrix units.”

Three-dimensional condylar displacement and remodelling following correction of asymmetric mandibular prognathism with maxillary canting

The aim of this study was to investigate the three-dimensional condylar displacement and long-term remodelling following the correction of asymmetric mandibular prognathism with maxillary canting. Thirty consecutive patients (60 condyles) with asymmetric mandibular prognathism >4 mm and occlusal canting >3 mm, treated by Le Fort I osteotomy and bilateral sagittal split ramus osteotomy, were included. Spiral computed tomography scans obtained at different periods during long-term follow-up (mean 17 ± 7.2 months) were gathered and processed using ITK-SNAP and 3D Slicer. The condyles were subjected to translational and rotational displacements immediately after the surgery (T2), which had not fully returned to the original preoperative positions at the last follow-up (T3). Condylar remodelling was observed at the last follow-up (T3), with the shorter side condyles subjected to higher surface resorption and overall condylar volume loss. The overall condylar volume on the shorter side was significantly reduced compared to the volume on the elongated side (−11.9 ± 90.6 vs −131.7 ± 138.2 mm3; P = 0.001). About 73%, 87%, 53%, and 54% of the shorter side condyles experienced resorption on the posterior, superior, medial, and lateral surfaces, respectively; in contrast, only 50% of the elongated side condyles showed resorption on the superior surface. Higher preoperative asymmetry was significantly correlated with increased postoperative condylar displacement (P < 0.05). The vertical asymmetry and the vector of condylar displacement were associated with the resultant remodelling process. It is concluded that condylar resorption of the shorter side condyle, which may affect the long-term surgical stability, has to be considered.

Rare case of skeletal third class in a subject suffering from Solitary Median Maxillary Central Incisor syndrome (SMMCI) associated to panhypopituitarism

BackgroundThe median solitary maxillary central incisor syndrome (SMMCI) is a rare malformative syndrome consisting of multiple defects, mainly found on the body midline. It can be correlated to the etiopathological and phenotypic pattern of panhypopituitarism. This case-report describes the rare case of a patient suffering from SMMCI and panhypopituitarism, showing an unusual craniofacial morphology.Case presentationFrom the cephalometric analysis, a skeletal class III was identified (despite the other cases described in literature described as skeletal class II), derived from hypomaxillia and mandibular protrusion. A convex lip profile, with tendency to mandibular hyper-divergency, airway patency, anterior and posterior cross-bite were observed. At the clinical examination, a maxillary cant was evident on the frontal plane that appeared asymmetric, with the prevalence of the third lower part of the face. There were some dysmorphic signs such as: small nose, rectilinear eyelid line and reduced interocular distance.ConclusionsThe present clinical case shows how, despite the literature, SMMCI can be associated with a III skeletal class, with maxillary hypoplasia and mandibular protrusion. The interdisciplinary collaboration between dentist and pediatrician is therefore important for the early interception of the malocclusions associated with these syndromes.

Mandibular Distraction Osteogenesis First for Children With Severe Unilateral Hemifacial Microsomia: Treatment Strategy and Outcomes.

The treatment for severe hemifacial microsomia (HFM), especially type III case, is extremely difficult. Mandibular distraction osteogenesis (MDO) was rarely used as the primary choice in the treatment of severe type cases. The authors sought to observe the short-term therapeutic outcomes of patients with severe unilateral HFM who underwent MDO first.A retrospective study of children underwent MDO or later received costochondral graft (CCG) for severe unilateral HFM from 2009 to 2019 was conducted. Cephalometric measurements and clinical variables were analyzed to evaluate the effectiveness of MDO first strategy for severe cases and compare disparity between Pruzansky-Kaban classification type IIb and type III groups.Thirty-six patients (23 males and 13 females) underwent MDO first for severe HFM were included for analysis in the present study. The average age at MDO was 8.33 ± 2.03 years. At the last follow-up, MDO acquired significant improvement in mandibular height, maxillary cant, chin deviation, lip commissural line tilt, and clinical chin deviation (P < 0.05). Distraction results were stable during the short-term follow-up in terms of the mandibular height ratio and maxillary cant (P > 0.05).MDO is a proper primary method for suitable type IIb and type III HFM cases. MDO can immediately and significantly improve the facial skeleton deficiency, extend the associated soft tissue at the same time, and lay foundation for secondary surgery. MDO can achieve the downgrade of HFM deficiency severity. MDO followed by costochondral graft can get satisfactory esthetic and structural consequence for type III patients.

Assessment of maxillary canting on cone beam computed tomography and digital models: A retrospective study and proposal of a method

Objectives. The mounting of the plaster casts on articulator procedure is routinely performed in orthognathic surgery to assess canting of the maxillary occlusal plane, but the currently used protocols and reference plane could be source of errors which affect reliability. Nowadays the assessment of canting of the maxillary occlusal plane could be also performed with an entirely digital protocol. Aim of the study was to propose a method to evaluate canting in patients affected by Unilateral Condylar Hyperplasia, comparing the measurements performed on digital models matched on CBCT with those made on traditional articulator.Materials and methods. A retrospective cross-sectional study was designed on 20 patients affected by vertical Unilateral Condylar Hyperplasia treated in the Units of Orthodontics and Maxillo-Facial Surgery. The canting of the maxillary occlusal plane was measured on plaster casts mounted on the conventional articulator and the measures were compared with those made on digital models matched on CBCT, according the protocol developed in our Unit. Molar, canine and basal difference were measured. To compare the two protocols and to test the agreement, we performed descriptive statistics, comparison between means and Bland Altman analysis. P value was set at 0.05.Results. Statistic comparison demonstrated agreement between measurements performed with the digital protocol and conventional physical method.Conclusion. Measurements of canting with digital protocol are comparable to the physical standard method. A total digital protocol allows faster availability and storage of patient's data and better communication between orthodontist and maxillo-facial surgeon, especially in patients affected by three-dimensional malocclusions.

Condylectomy as the treatment for active unilateral condylar hyperplasia of the mandible and severe facial asymmetry: retrospective review over 18 years

Unilateral condylar hyperplasia (UCH) of the mandible is a disorder affecting the condyle size, resulting in facial asymmetry. This study was a retrospective review of 27 patients with UCH who underwent condylectomy between 2000 and 2017 at Yonsei University Dental Hospital. Patient demographic characteristics were summarized. UCH was divided into three subtypes: hemimandibular elongation (HE, n=15), hemimandibular hyperplasia (HH, n=4), and osteochondroma (OC, n=8). Of the 27 patients, only one with the HE type and five (18.5%) with the OC type complained of joint pain. Bone scans of all patients showed higher uptake on the UCH side. Lip and maxillary canting was prominent in the HH and HE types. Five patients (18.5%) underwent condylectomy alone, 13 (48.1%) underwent condylectomy with orthodontic treatment, and nine (33.3%) underwent adjunctive jaw surgery with orthodontic treatment. The treatment modalities varied according to the subtype. In all OC type patients, removal of the hyperplastic condyle treated the facial asymmetry. Additional post-surgical orthodontic treatment was necessary in only three cases (37.5%). All HH type patients required mandibuloplasty. All patients showed a stable occlusal outcome without relapse and an improvement in subjective symptoms, despite a decrease in mouth opening of 2.2mm. These findings might be useful in treatment planning for UCH patients.

Asymmetric nasomaxillary expansion induced by tooth-bone-borne expander producing differential craniofacial changes.

To evaluate three-dimensional (3D) craniofacial changes induced by a non-surgical tooth-bone-borne rapid palatal expander (TBB-RPE) according to the symmetrical pattern of expansion, to investigate the 3D changes between the sides in patients with asymmetric expansion, and to identify the related factors of asymmetric expansion. Sixty-six patients (mean age: 19.3±5.7years) treated with TBB-RPE were divided into a symmetric expansion group (Group S, n=46) or asymmetric expansion group (Group A, n=20). Group S was subdivided into Group Ss (n=27), with bilateral frontomaxillary suture (FMS) split, and Group Sn (n=19), with no FMS split. Pre- and post-expansion cone-beam computed tomography images were superimposed, and the common coordinated system was set. All landmarks were designated as coordinate pairs, and treatment changes were automatically calculated. Analysis of variance was conducted for intergroup comparison of craniofacial changes, and logistic regression analysis was performed to identify the related factors of asymmetric expansion. The frequency of asymmetric expansion was 30.3%. Group A with unilateral FMS split showed less craniofacial changes than Group Ss and more changes than Group Sn. Group A exhibited different nasomaxillary displacement between the two halves, showing greater changes in the FMS-split side. Among the tested six variables (age, gender, Angle's classification, unilateral crossbite, maxillary cant and chin deviation), chin deviation was uniquely associated with asymmetric expansion. Tooth-bone-borne rapid palatal expander had a risk of asymmetric expansion, especially in facial asymmetric patients with chin deviation, producing different craniofacial changes from symmetric expansion.

Chair side measuring instrument for quantification of the extent of a transverse maxillary occlusal plane cant

BackgroundTreatment planning the correction of a transverse maxillary occlusal plane cant often involves a degree of qualitative “eyeballing”, with the attendant possibility of error in the estimated judgement. A simple chair side technique permits quantification of the extent of asymmetry and thereby quantitative measurements for the correction of the occlusal plane cant.MethodsA measuring instrument may be constructed by soldering the edge of a stainless steel dental ruler at 90° to the flat surface of a similar ruler. With the patient either standing in natural head position, or alternatively seated upright in the dental chair, and a dental photographic retractor in situ, the flat under-surface of the horizontal part of this measuring instrument is placed on a unilateral segment of a bilateral structure, e.g. the higher maxillary canine orthodontic bracket hook. The vertical ruler is held next to the contralateral canine tooth, and the vertical distance measured directly from the canine bracket to the flat under-surface of the horizontal part of the measuring instrument.ResultsThis vertical distance quantifies the overall extent of movement required to level the maxillary occlusal plane.ConclusionsThis measuring instrument and simple chair side technique helps to quantify the overall extent of surgical levelling required and may be a useful additional technique in our clinical diagnostic armamentarium.

Multi-stage multi-disciplinary treatment of ankylosis of the temporomandibular joints with prostheses in the treatment of children and adolescents with ankylosis of the temporomandibular joints leading to full facial rehabilitation

Background: (TMJ) ankylosis is a pathological condition characterized by articular bony or fibrous tissue fusion. It can cause a dentofacial deformity resulting limitation of mandibular function, malocclusion, retrognathia, mandibular asymmetry, maxillary cant, malnutrition and poor oral hygiene TMJ ankylosis is a serious complication after a trauma, local or systemic infection, or systemic diseases. The highest incidence in children is trauma. Clinical manifestation can vary according to severity of ankylosis, time of onset ankylosis and duration. Early joint involvement, less then 15 years causes severe facial deformity and loss of function. Treatment in children always has a particular importance. The goal is, to release ankylosis, to prevent reankylosis, to provide functioning as early as possible and eventually to maintain a normal growth.

Computer-assisted osteotomy guides and pre-bent titanium plates improve the planning for correction of facial asymmetry

This study investigated the surgical outcomes and accuracy of computer-assisted osteotomy guides and pre-bent titanium plates in the treatment of patients with facial asymmetry. Thirteen patients with facial asymmetry undergoing bimaxillary orthognathic surgery were included. Virtual simulation of Le Fort I osteotomy, sagittal split ramus osteotomy, and genioplasty, if needed, was conducted on the preoperative three-dimensional model. Computer-assisted osteotomy guides and pre-bent titanium plates were produced and used in the actual operation. The postoperative outcome was assessed for facial symmetry and surgical accuracy. All patients were followed up for at least 18 months and their level of satisfaction was investigated. Use of the computer-assisted osteotomy guides and pre-bent titanium plates was successful in all patients. Maxillary canting, mandibular ramus inclination, and mandibular length were corrected on both sides postoperatively. Superimposition of the surgical simulation and postoperative images demonstrated favourable accuracy. Quantitative analysis revealed a mean linear difference of <0.60mm in the maxilla and 1.57mm in the mandible. All patients were satisfied with the surgical outcome; there were no complications or cases of relapse during follow-up. The application of computer-assisted osteotomy guides and pre-bent titanium plates achieved favourable outcomes and accuracy, improving planning for the correction of facial asymmetry.

Part 2: Is the maxillary canting and its surgical correction in patients with CFM correlated to the mandibular deformity?

IntroductionPatients with Craniofacial Microsomia (CFM) mandibles Types I/IIa benefit from combined LeFort 1 osteotomy and Mandibular Distraction Osteogenesis (LeFort + MDO); Type IIb from LeFort + MDO or Bimaxillary osteotomy (BiMax); and Type III from BiMax (with 50% of cases having preceding mandibular procedures, including patient-fitted prosthesis); as seen in Part 1. This leads to the question how maxillary and mandibular hypoplasia are correlated and influence the types of maxillary correction. Material and methodsA retrospective chart study was conducted including patients diagnosed with CFM from 2 large craniofacial units. Radiographic and clinical information were obtained. Unilateral affected patients with available (ConeBeam) CT-scan of the maxillary-mandibular complex, without treatment of the upper jaw prior to the CT-scan were included. A maxillary cant grading system was set up and evaluated. Pearson correlation coefficients were used to correlate the maxillary cant and the severity of the mandibular hypoplasia. ResultsEighty-one patients were included, of whom 39.5% had a Pruzansky-Kaban type III mandible and 42% a mild maxillary cant. There was a significant positive correlation between severity of the mandibular hypoplasia and the categorized canting (r = 0.370; p < 0.001; n = 81). Twenty-four patients had maxillary surgery, mainly a BiMax. ConclusionThere is a positive correlation between the severity of mandibular hypoplasia and maxillary cant. The severity of mandibular hypoplasia seems to dictate an intervention for both maxillary and mandibular surgery.

Lip Morphology in Patients With Facial Asymmetry Can Be Corrected by 2-Jaw Surgery

Surgical orthodontic patients with facial asymmetry frequently show asymmetry of the lips, and this is often a major complaint of patients. This study investigated whether lip asymmetry associated with the maxilla and mandible was improved when 2-jaw surgery was performed in surgical orthodontic treatment. Inclusion criteria for this retrospective cohort study were 1) an anteroposterior maxillary relation defined as skeletal Class I; 2) menton (Me) tranverse deviation greater than 5.0mm; 3) maxillary cant greater than 3.0°; and 4) 2-jaw surgery. Primary predictor variables in this study were skeletal morphologic measurements (Me deviation, maxillary cant, and maxillary distance ratio) before and after treatment. Outcome variables were lip morphology measurements (labial commissure distance, lip angle, and lip area). Additional variables included age and gender. Vertical distances, angles, and area of the upper and lower lips were measured and compared before and after treatment. Hard tissues were measured using posteroanterior cephalograms. Paired t test and correlation coefficients were calculated. Fourteen patients (4 men [28.5%] and 10 women [71.5%]; mean age, 29yr) were included. Meaningful changes were observed in distance and angle measurements of the lips from before to after treatment. In area measurement, ratios of the area on the deviated side to that on the contralateral side for the upper and lower lips changed markedly and were close to 1.0 compared with before treatment. A relevant correlation was found between change in Me deviation and change in ratio of the height of the labial commissure. In cases of facial asymmetry caused by deviation of the maxilla and mandible, lip asymmetry can be adequately corrected by leveling the canted occlusal plane and positioning the Me toward the midline with 2-jaw surgery.

Simultaneous maxillomandibular distraction osteogenesis in hemifacial microsomia: Report of 7 cases

IntroductionThe goal in treating Hemifacial microsomia (HFM) is to improve facial symmetry, allow functional jaw movement, obtain stable occlusion, and achieve patient satisfaction. This study was planned with an aim to assess the outcome of simultaneous maxillomandibular distraction osteogenesis in hemifacial microsomia. Material & methodsSeven patients with hemifacial microsomia were included in this study and demographic data was obtained. Simultaneous maxillo-mandibular distraction was planned for correction of maxillary cant, vertical ramal lengthening and midline, by performing unilateral mandibular osteotomy in ramus and distractor fixation, a Le Fort I osteotomy, with fixation at contralateral zygomatic buttress and intermaxillary elastics. Derriford Appearance Scale was used to measure individual responses to address problems of appearance. Results6 males and 1 female, with age range 18–26 years, mean 22.14 were included in the study. Maxillary occlusal cant varied from 4–16°, mean 9.85° and distraction achieved ranged from 12–19mm, mean 15.57. Preoperatively DAS score ranged from 42–61, mean 51.7 and improved to 10–27, mean 18.4. 100% success was achieved in 5 cases, while other two showed 96% and 99% success. ConclusionSimultaneous maxillomandibular distraction osteogenesis improves facial esthetics and obviates the need for postoperative orthodontics, minimizing the treatment period.

Computer-assisted surgical planning and simulation for unilateral condylar benign lesions causing facial asymmetry

The purpose of this study was to investigate the best surgical sequence for the treatment of unilateral condylar benign lesions causing facial asymmetry by applying computer-assisted surgical planning and simulation. Computed tomography (CT) data from 12 patients whose maxillary cant was corrected by maintaining the vertical position of the central incisors and equally intruding the long side of the maxilla and extruding the short side were analyzed by ProPlan CMF 1.4 software (Materialise Medical, Leuven, Belgium). Condylectomy and double jaw orthognathic surgery with 2 different surgical sequences were simulated: 1) maxillary LeFort I osteotomy first (MaxF), then condylectomy, followed by bilateral sagittal split ramus osteotomy (BSSO); and 2) mandible first (ManF), beginning with condylectomy, then BSSO, and lastly LeFort I osteotomy. The greatest space between the maxillary and mandibular first molar in the interim positions was measured virtually to compare the 2 surgical sequences. The vertical distance between the upper and lower teeth of ManF patients was significantly smaller than that of MaxF patients (mean 2.99mm, P<.001). When occlusal cants are corrected by equally intruding one side and extruding the other side of the maxillary dentition, the interim position is more conducive to sequencing corrective surgery by performing condylectomy, then BSSO, followed by Le Fort I osteotomy.

Pre-arthroplasty simultaneous maxillomandibular distraction osteogenesis for the correction of post-ankylotic dentofacial deformities

The aim of this study was to evaluate the hard and soft tissue changes after pre-arthroplasty simultaneous maxillomandibular distraction osteogenesis for the correction of post-ankylotic dentofacial deformities. This prospective study included 10 patients with unilateral temporomandibular joint (TMJ) ankylosis who presented with a facial deformity and a maxillary cant. Informed patient consent was obtained for participation. Simultaneous maxillomandibular distraction was planned based on clinical and radiographic examinations. A horizontal mandibular osteotomy was performed in the ramus and the distractor device was fixed. A bilateral Le Fort I osteotomy was then performed and a four-hole straight plate was fixed on the contralateral zygomatic buttress to act as a fulcrum. After a latency period of 5 days, the distractor was activated twice daily by 0.5mm until the required vertical lengthening was achieved. Intermaxillary fixation was maintained during the entire distraction period. After a consolidation period of 8–12 weeks, the distractor was removed. The TMJ ankylosis was released and a temporal fascia interpositional arthroplasty was performed as second surgery, along with a genioplasty if needed. All patients were followed up for a period of 12–24 months. A marked improvement in the facial asymmetry was noted in all cases. The occlusal cant and mandibular retrusion improved satisfactorily, and the average postoperative inter-incisal opening was 35.6mm. Pre-arthroplasty simultaneous maxillomandibular distraction offers a good treatment outcome, as it allows improvements in facial aesthetics as well as function.

The skeletal and dentoalveolar stability of the maxilla after LeFort I osteotomy for cant correction

Objectives: The aim of this study was to assess the stability of the maxilla after LeFort I osteotomy for correction of maxillary canting caused by skeletal or dentoalveolar disorders.Methods: The patients underwent conventional LeFort I osteotomy for correction of maxillary canting. Frontal cephalograms were obtained before surgery (T1), immediately after surgery (T2) and more than 1 year after surgery (T3). The angles between the line connecting bilateral latero-orbitales (Lo-Lo′) and zygoma planes (ZPs) or occlusal planes (OPs) were measured, and the distances from the Lo-Lo′ or ZP to the left and right upper first molars were also measured to assess skeletal or dentoalveolar disorders at three time points (T1-T3).Results: In cases in which the Lo-ZP was more than 2° before surgery (T1), the Lo-ZP changed from 2.28° (T1) to 1.57° (T2) or 1.50° (T3). In cases in which the Lo-ZP changed less than two degrees and the Lo-OP changed more than 2°, the Lo-OP changed from 2.69° (T1) to 1.41° (T2) or 1.08° (T3), and these changes were significant. Lo-ZP was nearly stable across the time points. The distances from the Lo-Lo′ or ZP to left and right upper first molars were nearly stable from T2 to T3.Conclusion: Skeletal and dentoalveolar stabilities were obtained regardless of whether the canting was caused by skeletal or dentoalveolar disorder.