Occlusal outcomes in combined orthodontic and orthognathic treatment

Investigation of orthognathic surgery indicators-combination with index of orthognathic functional treatment needs (IOFTN) and maxillofacial morphometric analysis

PURPOSE

The aim of this retrospective study was to determine orthognathic surgery indicators for Japanese patients with jaw deformities using both Index of Orthognathic Functional Treatment Needs (IOFTN) and maxillofacial morphometric analysis.

SUBJECTS AND METHODS

The subjects were 89 patients treated with orthognathic surgery and 92 patients treated with orthodontic treatment alone, and were classified as class I, II, or III according to the ANB angle. Based on the results for IOFTN and the results of cephalometric analysis, the indication criteria for orthognathic surgery were examined.

RESULTS

In IOFTN analysis, none of patients in the orthognathic surgery group were classified as category 1 or 2, while 48% of the patients in the orthodontic treatment group were classified as category 4 or 5. The results of the cephalometric analysis of patients in classified categories 4 and 5 showed that the orthognathic surgery group had significantly greater lateral mandibular deviation in Class I cases, significantly more severe degree of mandibular retrusion in Class II cases, and significantly more severe degree of mandibular prognathism in Class III cases. The results of the logistic regression analysis showed that IOFTN was a common variable as an indication criterion for orthognathic surgery, and several different variables were also selected from the cephalometric measurements in each group.

CONCLUSION

IOFTN is a highly sensitive and useful indicator as a criterion for orthognathic surgery. However, in the choice of treatment strategy, maxillofacial morphometric analyses and the patient's desired goal are important.

Functional needs in orthognathic patients with different sagittal skeletal discrepancies

OBJECTIVES

This retrospective study aimed to evaluate the relationship between the Index of Orthognathic Functional Treatment Need (IOFTN) and sagittal skeletal discrepancy (ANB angle) among orthognathic patients.

STUDY DESIGN

Records of 403 orthognathic patients (229 females/174 males, aged 16-50 years) were reviewed. Malocclusion type (incisor-based), sagittal skeletal relationship (ANB angle), and IOFTN scores were documented. Spearman correlation coefficient (r) and scatter plots were utilized to examine the relationship between functional need (IOFTN scores) and sagittal skeletal discrepancy (ANB angle). Regression analyses were conducted to determine the extent to which variations in IOFTN scores could be attributed to variations in ANB angles.

RESULTS

Class III malocclusion/sagittal skeletal pattern were most prevalent (62.3%). The Spearman correlation coefficient (r) for the entire sample was -0.297 (P < .001), indicating a weak negative correlation. Linear regression analysis demonstrated a coefficient of determination of 0.069, indicating that approximately 6.9% of the variance in IOFTN data could be accounted for by variations in ANB angles. Upon stratifying data by different malocclusions, coefficients of determination were 0.065, 0.034, and 0.089 for class I, II, and class III malocclusions, respectively.

CONCLUSION

The observed linear relationships between sagittal skeletal discrepancy (ANB angle) and IOFTN score were weak and lacked clinical significance.

Outcome measures of the surgery first approach for orthognathic correction of dentofacial deformities

In the surgery-first approach (SFA), orthognathic surgery is performed without the need for presurgical orthodontic treatment. This study was aimed at assessing the treatment durations and occlusal outcomes for a consecutive cohort of patients, with a range of dentofacial deformities, who had completed orthognathic treatment using SFA. The duration of orthognathic treatment was measured. The overall change in occlusion, and the quality of the final occlusion, were evaluated using the patients' study casts. A single, independent, calibrated operator carried out the occlusal scores, using the validated Peer Assessment Rating (PAR) index. This was repeated to test intraoperator reliability. A total of 51 patients completed surgery-first treatment during the study period. The mean (range) age at surgery was 23.3 (15-47) years. The pre-treatment skeletal jaw relationship was Class III in 39 cases, and Class II in 12 cases. The mean (SD) overall treatment duration was 11.7 (5.7) months. The intraexaminer reliability of assessing the occlusion was high. The PAR scores confirmed a significant improvement in the quality of occlusion at the completion of treatment, which compares favourably with previous studies on the conventional orthodontics-first approach. The surgery first approach can be effective at correcting both Class II and Class III malocclusion types with reduced treatment times.

Systematic Review and Meta-Analysis of the Index of Orthognathic Functional Treatment Need for Detecting Subjects with Great Need for Orthognathic Surgery

Index of Orthognathic Functional Treatment Need (IOFTN) Identifies patients with greatest need for orthognathic surgery. This systematic review looks into the available evidence on prevalence of patients with great treatment need (IOFTN 4&5) who had orthognathic surgery in previous studies. Literature search of the major electronic databases was carried out for articles published between 2014 and September 2023, looking for "Index of Orthognathic Functional Treatment Need","Orthognathic Surgery","IOFTN", "Epidemiology" and "Dentofacial Deformity". The prevalence of patients identified with IOFTN grades of 4&5 was calculated. A random-effect model was employed and the Forest and Galbraith plots were produced. The pooled prevalence estimate for subjects with IOFTN scores of 4&5 was calculated. The heterogeneity among studies was assessed with the I2 statistics. In total, 14 retrospective studies conducted between 2015 and 2019 in 7 countries (UK, New Zealand, Iran, Pakistan, Turkey, Malaysia, Japan) were included, reporting on 1339 orthognathic patients. The sample sizes ranged from 30 to 200. Only 7 studies reported on the subcategories of the IOFTN for grades 1, 2&3. The prevalence of orthognathic patients with IOFTN scores of 4 & 5 ranged from 79% to 100%. The heterogeneity I2 statistics was high (76%, random effects model) for 14 studies, but after removing 3 outlier studies reduced to zero. The pooled prevalence estimate for subjects with IOFTN scores of 4&5 was 93% (95% CI, 0.91-0.94%). According to this meta-analysis, IOFTN successfully identified 93% of patients who underwent orthognathic surgery with a great need for treatment (Grade 4 & 5). To enhance the identification of patients with well-compensated malocclusions, previous orthodontic treatment, or extreme occlusal deviations (e.g., proclination or retroclination of incisors), it would be advantageous to employ additional means alongside IOFTN for assessing orthognathic need in this group.

Complete Reoperation in Orthognathic Surgery

BACKGROUND

Complete reoperation is defined as undergoing reoperative/repeated jaw osteotomies, in a patient who previously underwent orthognathic surgery. The purpose of this study is to (1) describe jaw positions at three time-points (before primary and before and after reoperative surgery), (2) investigate factors necessitating reoperation, and (3) outline the technical challenges.

METHODS

Repeated orthognathic surgery cases >1-year out were included. Demographic, radiologic, and perioperative data were compiled. Repeated osteotomies (Le-Fort and/or bilateral split sagittal osteotomy, with or without genioplasty), were compared to their respective primary procedures. Statistical analysis was performed using t tests and z-scores.

RESULTS

Fifteen patients were included (28.1 years; 71 percent female). Reoperative/repeated surgery was most often needed to address iatrogenic bony malposition and asymmetry. Relapse was a less common indication. Time between reoperative and primary surgery was 14 months. Sagittal discrepancies (p = 0.029) were the most frequent reason for primary orthognathic surgery (e.g., mandibular hypoplasia (p = 0.023). Reoperative/repeated orthognathic was performed for asymmetry (p = 0.014). Repeated procedures used more 3-dimensional planning (p < 0.001), required all three osteotomies (p = 0.034), had longer operative times (p = 0.078), and all required hardware removal (p < 0.001). Anatomical outcomes were good with 100% patient satisfaction at long-term follow-up.

CONCLUSIONS

Reoperative/repeated orthognathic surgery is challenging and underreported in the literature. Whereas primary orthognathic typically addressed sagittal discrepancies, reoperative/repeated osteotomies were needed to correct iatrogenic bone malposition and asymmetries. Challenges include: re-planning, scar burden, need to remove integrated hardware, and repeated osteotomy/fixation. Despite these difficulties, outcomes and patient acceptance were good.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.