The effect of orthognathic surgery on the temporomandibular joint and oral function: a systematic review

Exploring the relationship between the number of systematic reviews and quality of evidence: an orthognathic surgery-based study

OBJECTIVE

We analyzed the quality and quantity of systematic reviews (SRs) of orthognathic surgery, the most frequently published topic in maxillofacial surgery.

STUDY DESIGN

We searched the PubMed database for SRs of orthognathic surgery with no restriction on the language of publication date. We assessed the certainty of evidence presented according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol and the Leiden Manifesto using the Grading of Recommendations Assessment, Development, and Evaluation approach. We analyzed the data using descriptive statistics, Pearson´s correlation test, and linear regression.

RESULTS

Of the 171 SRs evaluated, approximately one fifth presented evidence with a high level of certainty. The number of orthognathic surgery SRs has been increasing, and many SRs were published after very similar topics had already been published. There is no relationship between the impact factor and the certainty of evidence.

CONCLUSIONS

An excessive number of SRs of orthognathic surgery are published, and many SRs are superfluous, simply reporting previous findings. Clinicians should not base treatment decisions solely on the evidence presented in SRs, and journal editors and reviewers should evaluate these SRs more critically, particularly when they address topics that have already been covered in the literature.

Does Articular Disc Position Change Following Mandibular Setback Surgery?

BACKGROUND

Maintaining condyle position following bilateral sagittal split ramus osteotomy (BSSO) is crucial to minimizing postoperative relapse. However, the impact of BSSO on the articular disc position remains inconclusive.

PURPOSE

This study aimed to investigate the changes in articular disc position following setback BSSO surgery.

STUDY DESIGN, SETTING, AND SAMPLING

In this prospective cohort study, subjects with mandibular prognathism requiring setback BSSO were enrolled between August 2021 and June 2022 at the Oral and Maxillofacial Surgery Clinic, Faculty of Dentistry, Chiang Mai University, Thailand. Patients with surgical complications, loss of follow-up, or significant artifacts in their MR images were excluded.

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLES

The predictor variable was time. The articular disc position was assessed at 3 time points, preoperatively (T0), 3 months postsurgery (T1), and 6 months postsurgery (T2).

MAIN OUTCOME

The primary and secondary outcome variables were the changes in articular disc position between T0-T2 and T0-T1, respectively. Articular disc position was coded as normal, anterior disc displacement with reduction (ADDwR), anterior disc displacement without reduction (ADDwoR), and anterior disc displacement without reduction and degenerative joint disease (ADDwoR + DJD).

COVARIATES

Covariate variables collected included age (years), sex (male or female), asymmetry (present or absent), surgical procedure (single jaw (BSSO) or bimaxillary surgery), and setback distance (millimeters).

ANALYSES

Friedman's test with 80% power and a significance level of 0.05 was employed. Pairwise comparisons were performed using the Dunn-Bonferroni posthoc test to identify statistically significant differences.

RESULTS

The study included 16 subjects, 6 females and 10 males, with a total of 32 TMJs. Subjects had a mean age of 23.75 (4.57) years. The proportion of TMJs with normal disc position postoperatively increased from 3 (9.4%) to 19 (59.4%). Statistically significant differences were found in the changes in disc position over time (P < .001).

CONCLUSIONS

Following setback BSSO, the articular discs underwent changes, with a majority of ADDwR cases transitioning to a normal position. Cases with ADDwoR also demonstrated disc reduction capability after surgery. The combined orthodontic treatment and setback BSSO appear to have an effect on articular disc position in skeleton class III patients.

Role of Three-Dimensional Printing in Treatment Planning for Orthognathic Surgery: A Systematic Review

Three-dimensional (3D) printing refers to a wide range of additive manufacturing processes that enable the construction of structures and models. It has been rapidly adopted for a variety of surgical applications, including the printing of patient-specific anatomical models, implants and prostheses, external fixators and splints, as well as surgical instrumentation and cutting guides. In comparison to traditional methods, 3D-printed models and surgical guides offer a deeper understanding of intricate maxillofacial structures and spatial relationships. This review article examines the utilization of 3D printing in orthognathic surgery, particularly in the context of treatment planning. It discusses how 3D printing has revolutionized this sector by providing enhanced visualization, precise surgical planning, reduction in operating time, and improved patient communication. Various databases, including PubMed, Google Scholar, ScienceDirect, and Medline, were searched with relevant keywords. A total of 410 articles were retrieved, of which 71 were included in this study. This article concludes that the utilization of 3D printing in the treatment planning of orthognathic surgery offers a wide range of advantages, such as increased patient satisfaction and improved functional and aesthetic outcomes.

Does orthognathic surgery affect mandibular condyle position? A retrospective study

PURPOSE

The aim of this study is to analyze mandibular condyle position changes after bilateral sagittal split osteotomy (BSSO) and bimaxillary orthognathic surgery in patients operated at a single department by two surgeons in 2013-2022. Compared were groups of mandibular advancement vs setback and bimaxillary vs BSSO.

METHODS

Ninety-nine subjects were included. Inclusion criteria were patients who underwent one of the BSSO or bimaxillary surgery and had CT scans performed before and after surgery. Preoperative CT scans were performed 1 day before surgery and postoperative CT scans 6-12 months afterwards. Changes in mandibular condyle position were measured in axial and sagittal planes.

RESULTS

CT condylar position measurements indicated significant postoperative changes in AB angle bilaterally (p =  < 0.001). In mandibular advancement and setback comparison, values were significantly lower in ABL angle values in the setback group (p = 0.011326) and significantly higher in FDR in the advancement group (p = 0.005795). There were no statistically significant changes found in BSSO and bimaxillary group comparison.

CONCLUSION

Within the limitations of this study, it can be concluded that orthognathic surgery does have a moderate effect on position of the condyles, especially condylar rotation in transversal axis.

Does Social Media Affect a Patient's Decision to Undergo Orthognathic Surgery?

Orthognathic surgery, also known as corrective jaw surgery, is a procedure that corrects abnormalities of the jaw and face. It is used to treat malocclusions, where the teeth and jaws are misaligned. This surgery can improve the function and appearance of the jaw and face, leading to improved mastication, speech, and quality of life for the patients. To assess if social media had any effect on the patients' decision to undergo orthognathic surgery, a self-administered online questionnaire was distributed to patients who had undergone orthognathic surgery at the Oral and Maxillofacial department through the health information system (BESTCare, 2.0A) to participate in the study. In total, 111 responses were recorded from the patients, with 107 agreeing to answer the questionnaire and 4 refusing to answer. Twitter was a source of information about orthognathic surgery for 61 patients (57%). When using a social media platform, 3 patients (2.8%) were influenced by an advertisement or an educational post on social media that presented the surgical correction of the jaws, while 15 (14%) believed that they had been somewhat influenced, and 25 (23.4%) picked their surgeon through social media. Fifty-six patients (52.3%) took the neutral position regarding whether information on social media had answered their questions and concerns regarding the surgical procedure. Social media did not influence patients' decision to undergo the procedure. Surgeons and specialists must utilize their platforms to answer any concerns or questions from any patient undergoing or having undergone this corrective jaw surgery.

Changes in Preexisting Temporomandibular Joint Clicking after Orthognathic Surgery in Patients with Mandibular Prognathism

This study aimed to investigate the changes in preexisting temporomandibular joint (TMJ) clicking and the new incidence of TMJ clicking after orthognathic surgery. A total of 60 patients (30 men and 30 women) with mandibular prognathism underwent intraoral vertical ramus osteotomy (IVRO) for a mandibular setback. The setback amount and TMJ clicking symptoms (preoperative and one year postoperative) were recorded. To assess the risk of new incidence of TMJ clicking in asymptomatic patients, the cutoff value for postoperative mandibular setback was set at 8 mm. The left and right mandibular setbacks were 11.1 and 10.9 mm in men, respectively, and 10.7 and 10.0 mm in women, respectively. Thus, no difference in setback amount on either side was observed between the sexes. The improvement rate in patients with preexisting TMJ clicking was 69.2% (18 of 26 sides); the postoperative improvement rates were 71.4% (setback amount > 8 mm) and 60% (setback amount ≤ 8 mm). IVRO may reduce the severity of preexisting TMJ clicking. A high setback amount (>8 mm) may not be associated with a considerable increase in the risk of postoperative TMJ clicking.

Condylar resorption following mandibular advancement or bimaxillary osteotomies: A systematic review of systematic reviews

Several systematic reviews have been published on the effects of mandibular surgery on condylar remodeling without reaching a consensus. The purpose of this systematic review of systematic reviews was to assess the impact of mandibular advancement or bimaxillary surgeries on condylar resorption. A literature search, using several electronic databases, was carried out by two reviewers independently. Article preselection was based on titles and abstracts, and final article selection based on full-text analysis of preselected studies. After final study selection, the quality of studies was assessed using the AMSTAR 2 tool. A decision algorithm was subsequently established to choose the best body of evidence. From an initial yield of 1'848 articles, 23 systematic reviews were identified for further analysis, with ten studies being included in the final selection. Despite the generally low quality of the reviews, certain associations could be made: young patients, female patients, and those with a high mandibular plane angle are more prone to condylar resorption following mandibular advancement osteotomies, especially if anterior rotation of the mandible is performed during surgery. Patients undergoing bimaxillary surgery also appear to have a higher risk of developing condylar resorption. In conclusion, these results confirm the multi-factorial nature of condylar resorption, stressing the need for well-controlled prospective studies with long-term follow-up to clearly identify potential risk factors associated with orthognathic surgery.

Evaluation of the Mandibular Condyle Morphologic Relation before and after Orthognathic Surgery in Class II and III Malocclusion Patients Using Cone Beam Computed Tomography

Simple Summary

In individuals with severe malocclusions, orthognathic surgery seeks to rebalance the relationships between the jaws by providing a stable occlusion, a healthy muscle balance, and the functioning of the temporomandibular joint. Cone beam computed tomography may be used to determine the position of the mandibular condyle in the glenoid fossa. This study aimed to assess how the position of the mandibular condyle varies in class II and III malocclusions before and after bimaxillary orthognathic surgery. Before and after orthognathic surgery, 56 TMJs from 28 patients were studied. Following surgery, both class II and class III patients experienced changes in the anterior joint space, posterior joint space, condyle position, and condyle angle. The preliminary findings are promising for determining changes in condyle position and joint spaces that might guide oral and maxillofacial surgeons to address a debilitating clinical affliction.

Abstract

This study aimed at evaluating the mandibular condyle position changes before and after bimaxillary orthognathic surgery in class II and III malocclusion patients. CBCT scans from patients who underwent bimaxillary orthognathic surgery were analyzed: Le Fort I osteotomy and bilateral sagittal split osteotomy (BSSO). Both condyles were independently assessed for their largest anterior and posterior joint spaces, smallest medial joint spaces, and condyle angles concerning the transverse line. In the sagittal plane, the minimum size of the anterior and posterior joint spaces was measured. In the coronal plane, the smallest medial joint space was measured. The position of the condyle within the glenoid fossa was determined before and after surgery. A total of 56 TMJs from 28 patients were studied. Following orthognathic surgery, the anterior and posterior space in class II increased. Postoperatively, the anterior joint space in class III decreased. In 42.85% of malocclusion class II patients and 57.14% of malocclusion class III patients, the pre-and post-surgical position of the condyle changed, the condyle was anteriorly positioned (42.85%) in class II patients and centrically positioned (71.4%) in class III patients. Significant changes in the joint space, condylar position, and condyle angle were found in the class II and class III subjects.

Examination of factors affecting condylar bone changes following surgical-orthodontic treatment

OBJECTIVE

To identify factors affecting condylar bone changes following surgical-orthodontic treatment.

METHODS

A total of 200 patients with dentofacial deformities were classified into skeletal Classes I, II, and skeletal Class III groups consisting of 61 and 139 subjects, respectively. Temporomandibular joints (TMJs) were evaluated using clinical findings and computed tomography images before treatment, immediately before surgery, and 6 months after surgery.

RESULTS

Condylar bone changes occurred at a significantly higher rate after surgery in both groups. Factors related to condylar bone changes following surgical-orthodontic treatment included skeletal Class I or II, disc displacement, and condylar bone changes before treatment. There were three cases with condylar bone changes after surgery that were diagnosed with condylar resorption and skeletal Class II and anterior disc displacement before surgery.

CONCLUSION

Condylar resorption could occur when the load on the condyle increases after orthognathic surgery and exceeds the permissible limit.

Incidence and management of condylar resorption after orthognathic surgery: An overview

Objective

Condylar resorption (CR) is one of the major post-surgical complications of orthognathic surgery. This systematic review (SR) aimed to evaluate epidemiological data, risk factors, and therapeutical management of CR.

Methods

Six databases were screened by two investigators until September 2020 to obtain all SRs. After reading the titles and abstracts, eligible SRs were determined and data extraction was performed. Using the latest version of A Measurement Tool to Assess Systematic Reviews, the methodological quality of the included SRs was determined.

Results

Ten SRs with low or critically-low methodological quality were included in this review. Mandibular hypoplasia on the sagittal plane and hyperdivergent growth pattern on the vertical plane were the most common skeletal alterations in which CR could occur after orthognathic surgery. Post-operative condylar changes were analyzed both on two-dimensional and three-dimensional (3D) radiographic examinations. The incidence of CR was not related to the fixation method. Based on the severity of the pathological conditions, management of CR can include conservative or surgical therapy.

Conclusions

Despite the limited evidence in literature, CR is considered a consequence of orthognathic surgery. However, an accurate diagnosis of CR and a better orthognathic surgical planning must include 3D radiographic examinations to improve pre- and post-surgical comparison. Well-designed studies with long-term follow-up and 3D data are needed to clarify the findings of this analysis..

Orthognathic Surgery of the Mandible

Orthognathic surgery performed in conjunction with orthodontic treatment is commonly performed to correct skeletal irregularities and realign the maxillomandibular relationship to improve occlusal function and facial esthetics. A thorough understanding of soft tissue esthetics, skeletal and occlusal relationships, and surgical techniques is required to obtain successful results. Surgical techniques have evolved greatly throughout history, as technological advances such as virtual surgical planning have become available and widely used to obtain predictable movements with minimized complications. The aim of this article is to review the orthognathic surgical procedures of the mandible, with particular attention to the indications, contraindications, preoperative assessment, surgical technique, and possible complications encountered.

Quality of Life After Class III Repair Orthognathic Surgery: Five-Year Retrospective Study

OBJECTIVE

To evaluate the effect of orthognathic surgery on the long-term quality of life of patients with presurgical skeletal Class III and to identify its strongest effect-whether esthetic, social, or functional.

MATERIALS AND METHODS

In this retrospective cohort study, the subjects were patients after orthognathic surgery for repairing skeletal Class III. Fifty-five patients who had undergone orthognathic surgery from 2013 to 2018 in the oral and maxillofacial surgery department participated in this study. Each participant completed a modified questionnaire used to assess the patient's esthetic, social, and functional abilities after orthognathic surgery.

RESULTS

The rate of esthetic improvement in orthognathic surgery patients was 88%. More than four-fifths (81.8%) of the patients reported improvement in their personal and social self-esteem and confidence. Finally, 40.7% of the patients reported functional improvement. No significant differences between male and female patients were found. All but one of the patients recommended orthognathic surgery for patients with similar problems. One in six (17.3%) patients was dissatisfied with the nasal appearance after the surgical procedure, while almost a quarter (21.8%) reported worsening of their mouth opening, and 25.4% reported worsening of TMJ (Temporo-Mandibular Joint) symptoms. Analysis of the results revealed no statistically significant pattern connecting preoperative overjet or overbite measures with satisfaction rates.

CONCLUSIONS

In this study, patient satisfaction with the orthognathic surgical procedure was mostly a result of improvements in facial esthetics, followed by psychological well-being and functional abilities. Most dissatisfaction after the orthognathic surgical procedure was related to nasal appearance, mouth opening, and TMJ complaints.

Functional Outcomes Following Temporomandibular Joint Dissection Performed During Surgery for Skull Base Tumors

BACKGROUND

During skull base tumor surgery, temporomandibular joint (TMJ) dissection is commonly performed. The impact of this procedure on patients' postoperative diet and TMJ function is a matter of concern to surgeons.

METHODS

We reviewed the Craniomandibular Index (CMI) for 32 patients (15 men and 17 women) who underwent TMJ dissection during surgery for skull base tumors between August 2015 and May 2018.

RESULTS

Fifteen patients underwent removal of the mandibular condyle, and 17 had the condyle preserved. Twenty-one patients mainly underwent infratemporal fossa approach, and 11 underwent extended temporal bone resection. No significant difference between pre- and postoperative diet was observed in any group. Significant differences in CMI index were seen in all groups. The highest score was 0.115 of Dysfunction Index, observed postoperatively in the group that underwent condyle removal.

CONCLUSIONS

For skull base tumor surgery, TMJ dissection has no significant impact on postoperative diet. Patients who underwent removal of the mandibular condyle have significantly worse postoperative TMJ function.

Incidence of condylar resorption after bimaxillary, Lefort I, and mandibular surgery: an overview

The aim of the present overview was to evaluate the outcomes of systematic reviews to determine the incidence of condylar resorption in patients submitted to orthognathic surgery and analyze whether the risk of developing this condition is related to a specific type of surgery. Searches were conducted in the PubMed/MEDLINE, Embase, and Cochrane electronic databases for systematic reviews with quantitative data on condylar resorption due to any type of orthognathic surgery for dentoskeletal deformities published up to May 25, 2019. The AMSTAR 2 and Glenny tools were applied for the quality appraisal. Five systematic reviews were included for analysis. Only one article was considered to have high quality. Among a total of 5128 patients, 12.32% developed condylar resorption. From those patients, 70.1% had double jaw surgery, 23.4% had mandibular surgery alone, and in 6.5% a Lefort I technique was used. Based on these findings, bimaxillary surgery could be considered a risk factor for condylar resorption. However, these results should be interpreted with caution, since other factors, such as pre-operative skeletal deformities, type of movement, and type of fixation, can contribute to the development of this condition. Further studies should consider reporting main cephalometric data, temporomandibular diagnosis, hormonal levels, and tomographic measures before and after the surgery at least every 6 months during the firsts two years to identify accurately risk factors for condylar resorption.

The Effect of Orthognathic Surgery on Temporomandibular Joint Function and Symptoms: What are the Risk Factors? A Longitudinal Analysis of 375 Patients

PURPOSE

The effects of orthognathic surgery (OGS) on the temporomandibular joint (TMJ) are still controversial. Based on a high-volume uniform collective, the function and clinical symptoms of the TMJ and the dysfunction index (Di) by Helkimo were evaluated prior and up to 2 years after OGS.

METHODS

A longitudinal cohort study was performed between 2006 and 2016. A comprehensive examination focusing on TMJ function, temporomandibular disorder (TMD) symptoms, and the Di had been performed preopertaively (T0) and postoperatively at 6 weeks (T1), 6 months (T2), 1 year (T3), and 2 years (T4). The predictor variables used were sex, age, skeletal class, type of surgery, and amount of dysfunction or number of TMD complaints before treatment. The outcome of this study was TMD symptoms and the Di. Descriptive and bivariate statistics were computed, and the significance level was set at P < .05.

RESULTS

The sample consisted of 375 patients (247 women, 128 men, mean age 28.1 ± 9.4 years), 269 with skeletal Class II (71.7%) and 106 with skeletal Class III (28.3%) treated with sagittal split osteotomy bilateral sagittal split osteotomy (n = 173) or Le Fort I and bilateral sagittal split osteotomy (n = 202). Severe signs of dysfunction (Di 2/3) were seen in 5.9% of the patients before OGS and in 2.1% of the patients 2 years after OGS. The difference in Di (Di0/1 and Di2/3) between T0 and T1/T2 was statistically significant (P = .028; P = .011, respectively). TMD symptoms were significantly reduced 2 years after OGS (P = .028). Female gender (P = .013), skeletal Class II (P < .001), and counterclockwise rotation (P < .001) were the only risk factors significantly associated with the occurrence of TMD at T1.

CONCLUSIONS

The results of this study suggest that in most cases TMD symptoms can be significantly reduced and only a few can be induced with OGS. No risk factors were found for long-term effects on the TMJ.

Complications or rather side effects? Quantification of patient satisfaction and complications after orthognathic surgery-a retrospective, cross-sectional long-term analysis

OBJECTIVES

The aim of this clinical analysis was to evaluate intraoperative and early postoperative complications as well as late findings and the overall patient satisfaction following orthognathic surgery.

MATERIALS AND METHODS

In a retrospective, cross-sectional study, 119 patients after orthognathic surgery were included. Surgical approaches were single bilateral sagittal split osteotomy (BSSO (n = 52)), single LeFort-I osteotomy (n = 5) and bimaxillary osteotomy (LeFort-I + BSSO (n = 62)). Intraoperative and early (0-4 weeks postoperative) complications were investigated retrospectively (n = 119), whereas late findings and quality of life were assessed via clinical follow-up and survey (mean: 59 months postoperative) on 48 patients.

RESULTS

Bad split (n = 4/114) was the most common intraoperative complication followed by one case of severe bleeding. Regarding early postoperative complications, temporary damage of the inferior alveolar nerve after BSSO was most common (n = 33/114), followed by facial nerve dysfunction (n = 3), failed osteosynthesis (n = 2) and one case of postoperative dyspnoea. Permanent hypaesthesia of the lower lip was the most prevalent (n = 28/45^{(BSSO and LeFort-I + BSSO)}) late finding with varying extent, followed by temporomandibular dysfunction (TMD) (n = 25/48). Skeletal relapse mostly occurred after class II treatment, followed by class III, posterior crossbite and open bite. Overall, the surgery improved the patients' self-perception (85.4%), with 60.4% of patients opting for surgery again.

CONCLUSIONS

Long-term complications after orthognathic surgery occurred more frequently than commonly described in the literature, and analyses of the quality of life show the need for more comprehensive preoperative patient education.

CLINICAL RELEVANCE

Hypaesthesia of the lower lip presented less as complication but rather as side effect following BSSO. As orthognathic surgery is mostly elective, preoperative patient education is of pivotal importance and should include proactive risk stratification.

Condylar form alteration on skeletal class II patients that underwent orthognathic surgery: An overview of systematic reviews

Background

Bilateral sagittal split osteotomy (BSSO) is commonly considered as the surgical technique of election for the treatment of skeletal class II with mandibular hypoplasia. After orthognathic surgery, condylar resorption can occur as a surgical relapse, which may affect the temporomandibular joint. Objective: This study aimed to summarise published systematic review that assess if orthognathic surgery with mandibular advancement performed on skeletal class II patients results in condylar form alteration.

Material and Methods

A literature search was performed using the electronic databases PubMed, Web of Science, Cochrane Library, Embase along with several sources of grey literature. Selection Criteria: Inclusion criteria were systematic reviews published until December 2019, of skeletal class II patients aged more than 18 years old that underwent BSSO with mandibular advancement surgery. Data collection: The electronic search identified 37 publications. Four publications fulfilled the inclusion criteria and were included in this meta-analysis. Qualitative assessment of the selected studies was performed using the Assessment of Multiple Systematic Reviews – AMSTAR 2 checklist.

Results

Four systematic reviews were included in this review. Despite its low incidence all studies reported condylar resorption. However, there were methodological limitations in all assessed articles.

Conclusions

The alteration of the condylar form may be a consequence of BSSO with mandibular advancement surgery. Additional high quality prospective research assisted by 3D-imaging technology is needed to allow more definite conclusions.

Key words:Evidence-based orthodontics, TMJ, Class II, mandibular advancement, malocclusion, Angle class II.

Combined Orthodontic-Orthognathic Approach for Dentofacial Deformities as a Risk Factor for Gingival Recession: A Systematic Review

PURPOSE

The objective of this systematic review was to evaluate the risk of development of gingival recession (GR) as a result of the combined orthodontic-orthognathic approach.

MATERIALS AND METHODS

The PubMed, Google Scholar, ClinicalTrials.gov, and Cochrane Library databases were searched. Included articles mentioned gingival parameters in their materials and methods sections; specifically, they evaluated GR, which was measured before and after the surgical procedure. Study parameters such as methodology, evaluation period, sample characteristics, and follow-up were extracted by 2 authors independently.

RESULTS

In total, 133 relevant articles were identified from the databases; after screening and full-text analysis, 9 studies were included in this systematic review. Meta-analysis could not be conducted because of considerable heterogeneity in methods. The incidence of GR in the range of 0.5 to 3.0 mm as a significant clinical finding after orthognathic surgery showed statistically significant differences in all included articles. Among patients with GR, the mean age was 23.0 to 29.5 years and the mandibular incisors were the most common site. However, no case of recession greater than 3.0 mm was associated with surgery.

CONCLUSIONS

On the basis of the findings of this review, GR of approximately 0.5 to 3.0 mm is a common finding after the combined orthodontic-orthognathic approach. Although periodontal damage up to 3 mm can be observed as an isolated finding in mainly the incisors, true recession is not associated with orthognathic surgery in general.

Evaluation of border movement of the mandible before and after orthognathic surgery using a kinesiograph

PURPOSE

The purpose of this study was to examine the changes in the mandibular border movement between class II and class III jaw deformity patients before and after orthognathic surgery, by using the same device.

SUBJECTS

and Methods: Eighty one patients (28 in class II and 53 in class III) who underwent sagittal split ramus osteotomy (SSRO) with Le Fort I osteotomy using absorbable plate fixation and 27 controls with normal occlusion were enrolled. Mandibular border movement (observed using a kinesiograph) was recorded with a mandibular movement measure system (K7) before surgery, and at 6 months and 1 year after surgery. Time-course changes of 5 components of the mandibular border movement (MVO: Maximum vertical opening, CO to MAP: Maximum antero-posterior movement from centric occlusion, MLDL: maximum lateral deviation left, MLDR: maximum lateral deviation right, CO to MO: centric occlusion to maximum opening) were compared between classes II, III and controls statistically. The relationship between lateral cephalometric measurements and the components of mandibular border movement was also examined.

RESULTS

There was a significant difference in CO to MAP (P = 0.0025) and CO to MO (P < 0.0001) between class II and class III in the time-course change. In class III, mean and standard deviation of MVO were 44.5 ± 6.7 mm before surgery and 39.8 ± 6.8 mm after 1 year. Mean and standard deviation of CO to MAP were 25.2 ± 6.8 mm before surgery and 21.5 ± 7.9 mm after 1 year. Mean and standard deviation of CO to MO were 53.4 ± 9.0 mm before surgery and 47.3 ± 8.4 mm after 1 year. In class II, mean and standard deviation of MVO were 38.8 ± 5.8 mm before surgery and 36.2 ± 7.4 mm after 1 year. Mean and standard deviation of CO to MAP were 18.0 ± 6.3 mm before surgery and 17.8 ± 7.4 mm after 1 year. Mean and standard deviation of CO to MO were 43.1 ± 7.5 mm before surgery and 39.6 ± 10.5 mm after 1 year. In MVO, CO to MAP and CO to MO, the values after 1 year did not significantly reach the pre-operative values in class III (P = 0.0001, P = 0.0007 and P < 0.0001), although there was no significant difference between pre-operation and after 1 year in class II. In CO to MO, class II (mean and standard deviation 39.6 ± 10.5 mm) and class III (mean and standard deviation 47.3 ± 8.4 mm) still remained smaller values than control (mean and standard deviation 52.7 ± 9.2 mm) after 1 year (P < 0.0001 and P = 0.0095).

CONCLUSION

This study suggests that bi-maxillary surgery can have more influence on the reduction in the range of mandibular border movement including vertical or antero-posterior motion than lateral deviation motion, in both groups. The difference in the time-course change in the mandibular border movement between the groups might depend more on the mandibular length than on the movement direction of the mandible by surgery such as advancement or setback.

Oral Functional Behavior and Neurosensation After Adult Maxillomandibular Advancement for Obstructive Sleep Apnea in the Long-Term

PURPOSE

We evaluated and correlated the long-term subjective perioral neurosensory deficit intensity and oral functional behavior difficulty after maxillomandibular advancement (MMA) for adult obstructive sleep apnea (OSA).

PATIENTS AND METHODS

We implemented a long-term retrospective cohort study of adult subjects who had undergone MMA for OSA, with subjective assessments using 7-point visual analog scales. Adult subjects who had undergone MMA for OSA with a minimum of 5 years of follow-up data available who had agreed to participate were included in the present study. The 1-sample Wilcoxon signed rank test and Spearman correlation coefficients were used to evaluate the data. Statistical significance was set at the P < .05 level.

RESULTS

Of the 51 eligible subjects, 27 (53% response rate) were included in the present study. The mean age preoperatively was 59.8 years, with a mean follow-up of 12.7 years. Most subjects (85%) had, overall, reported the long-term subjective perioral neurosensory deficit intensity to be none to very mild (mode, 0; mean, 2.20; P < .05) and oral functional behavior to have none to very mild difficulty (mode, 0; mean, 1.6; P < .05). Statistically significant moderate to strong positive correlations between the subjective assessments of oral functional behavior and perioral neurosensory deficit intensity were found for chewing (r = 0.74), kissing (r = 0.50), eating (r = 0.80), speaking (r = 0.81), and drooling (r = 0.67).

CONCLUSIONS

Within the limitations of the present study, more than 12 years after MMA for severe OSA, most subjects (85%) had minimal to no subjective perioral neurosensory deficits and very minimal to no difficulty in the subjective assessment of oral functional behavior. Strong positive correlations between the subjective decreased perioral neurosensory deficit intensity and decreased oral function behavior difficulty suggest that the return of perioral neurosensation might contribute to the return of oral functional behavior.

Effect of bimaxillary orthognathic surgery on dysfunction of the temporomandibular joint: a retrospective study of 500 consecutive cases

We investigated the effect of bimaxillary orthognathic surgery on symptoms in the temporomandibular joint (TMJ) and predictive factors for postoperative dysfunction. A total of 500 patients with different craniofacial deformities who were having bimaxillary orthognathic surgery were assessed for overjet, overbite, maximal mouth opening, maximal protrusion, maximal lateral movement to both sides, and symptoms of TMJ dysfunction (pain on palpation, clicking, or crepitus) before operation and one year postoperatively. The panoramic radiographs taken on the same dates were assessed for reduction in the height of the ramus. Other variables were age, sex, segmentation of the maxilla, and additional genioplasty. Changes in the symptoms of dysfunction were investigated with the McNemar test. Measurements of the maximum mandibular movements taken preoperatively and postoperatively were compared using the paired t test. Multivariate logistic regression was used to assess the influence of the variables on symptoms preoperatively and postoperatively. The effect of occlusal stability (overjet and overbite) on postoperative symptoms in the TMJ was investigated with the unpaired t test. Women and class II patients had significantly more pain on palpation preoperatively, and a significant reduction in pain on palpation and clicking after operation. Predictive factors were preoperative crepitus for postoperative pain, and preoperative clicking for postoperative clicking. Patients with and without symptoms showed no significant differences in overjet and overbite postoperatively. Condylar resorption was found in 29 patients (5.8 %), and only 14 of them had symptoms in the TMJ. In patients with no preoperative symptoms or radiological abnormalities of the condyle, condylar resorption was rare (0.8 %). Orthognathic surgery has a beneficial effect on dysfunction of the TMJ as it reduces pain and clicking considerably. Patients should be informed, however, that TMJ disorders could still develop even if they had no symptoms preoperatively.

Temporomandibular joint function 10-15 years after mandibular setback surgery and six weeks of intermaxillary fixation

Intermaxillary fixation (IMF) is a classic method for immobilization of the mandible after mandibular fractures and corrective surgery. However, it has been suggested that IMF may be a risk for developing temporomandibular joint (TMJ)-related symptoms, especially when applied for longer periods.

Safety and Stability of Postponed Maxillomandibular Fixation After Intraoral Vertical Ramus Osteotomy

The purpose of this study was to evaluate the postoperative safety and long-term stability of bimaxillary orthognathic patients with postponed maxillomandibular fixation (MMF) after intraoral vertical ramus osteotomy.A total of 61 patients (21 male and 40 female patients; average age [SD], 21.7 [4.7]) were enrolled. All patients underwent maxillary LeFort I osteotomy and bilateral intraoral vertical ramus osteotomy for mandibular prognathism. During the hospital stay, postoperative airway compromise was observed and patients underwent MMF with wire at the second postoperative day. Stability was evaluated by measuring the position at each period: preoperative (T0), 2-day postoperative (T1), and 1-year postoperative.Postoperative dyspnea and respiratory distress were absent in all patients. The mean number of refixations in physiotherapy was 0.62 (0.86) and the mean duration of physiotherapy was 11.6 (5.5) days. The mean amount of mandibular setback was 12.56 (5.76) mm and menton movement 0.98 (2.36) mm superiorly (T1). The mean mandibular relapse at Pog was 0.87 (1.96) mm anteriorly. Menton showed 1.11 (1.41) mm superiorly movement 1-year postoperatively (T2).Despite its many advantages, intraoral vertical ramus osteotomy requires a period of MMF which can lead to early discomfort and airway-related emergency. In this study, the physiotherapy procedure and postoperative long-term stability in the postponed MMF group were not different from those of an immediate MMF group studied previously. It therefore constitutes a viable option for oral breathers and other compromised patients.

[Symphyseal bone distraction (part 1): benefit / risk ratio. A systematic literature review]

INTRODUCTION

The purpose of this systematic literature review is to evaluate the benefit / risk ratio of mandibular symphyseal distraction osteogenesis.

MATERIALS AND METHODS

Searches were made on Pubmed/Medline and Cochrane for randomized clinical trials and case series involving mandibular symphyseal distraction over the past 20 years with a patient sample greater than or equal to 10.

RESULTS

Of the 92 articles, 25 met the inclusion criteria. A controlled trial was selected, but no randomized trial. The other studies were all case series, 16 retrospective and 8 prospective. Distractors with bone or hybrid anchorage appear to lead to more periodontal and infectious complications due to the buccal position of the jack. Most complications are benign. However, the most difficult event to deal with is distraction device fracture. Symphyseal midline distraction increases the transverse dimension efficiently, reliably and sustainably, and appears to have no demonstrated deleterious effects on the ATMs for the three types of distractors.

DISCUSSION

Tooth-borne devices are recommended in most cases given their benefit / risk ratio. Furthermore, they do not require a second surgical procedure to remove them.

CONCLUSION

Mandibular symphyseal distraction osteogenesis is a reliable therapy whose exact limits and reproducibility remain to be defined by future prospective studies.

Virtual Planning of a Complex Three-Part Bimaxillary Osteotomy

In maxillofacial surgery, every patient presents special problems requiring careful evaluation. Conventional methods to study the deformities are still reliable, but the advent of tridimensional (3D) imaging, especially computed tomography (CT) scan and laser scanning of casts, created the opportunity to better understanding the skeletal support and the soft tissue structures. Nowadays, virtual technologies are increasingly employed in maxillofacial surgery and demonstrated precision and reliability. However, in complex surgical procedures, these new technologies are still controversial. Especially in the less frequent cases of three-part maxillary surgery, the experience is limited, and scientific literature cannot give a clear support. This paper presents the case of a young patient affected by a complex long face dentofacial deformity treated by a bimaxillary surgery with three-part segmentation of the maxilla. The operator performed the surgical study completely with a virtual workflow. Pre- and postoperative CT scan and optical scanning of plaster models were collected and compared. Every postoperatory maxillary piece was superimposed with the presurgical one, and the differences were examined in a color-coded map. Only mild differences were found near the osteotomy lines, when the bony surface and the teeth demonstrated an excellent coincidence.

Duration of orthognathic-surgical treatment

OBJECTIVE

The objective of this study was to determine the duration of orthognathic-surgical treatment conducted with conventional pre- and post-surgical orthodontic treatment phases.

MATERIAL AND METHODS

The study material was comprised of the files of 185 consecutive patients treated in Oral and Maxillofacial Unit, Tampere University Hospital, Finland, in 2007-2014. The files were reviewed and the following data was obtained: gender and age of patients, ICD-10 diagnosis, type of malocclusion, duration of pre- and post-surgical orthodontic treatment and type of operation.

RESULTS

Total treatment duration (median) from placement of separating rings for banding until fixed orthodontic appliances were removed and retention period started was 31.1 months, of which pre-surgical orthodontics took 24.4 months and postsurgical 6.4 months. Treatment duration (median) was in BSSO was 32.1, LeFort 1 30.1 and bimaxillary osteotomy 29.7 months. Orthodontic extractions were performed in 35 patients (19%). If the orthodontic treatment included tooth extraction, the duration of pre-surgical treatment was on average 10 months longer, which is a statistically highly significant difference (p < .001, linear regression).

CONCLUSIONS

Tooth extractions (excluding 3rd molars) included in pre-surgical orthodontic treatment prolong treatment time by an average of 8-9 months.