Corrective outcome and transverse stability after orthognathic surgery using a surgery-first approach in mandibular prognathism with and without facial asymmetry

The surgery-first approach for orthognathic correction of maxillary deficiency-is it stable? Three-dimensional assessment of CBCT scans and digital dental models

The aim of this study was to determine the skeletal stability of Le Fort I maxillary advancement following the surgery-first approach, by three-dimensional (3D) assessment of cone beam computed tomography (CBCT) scans and digital dental models. CBCT scans of 25 class III patients obtained 1 week preoperatively (T0) and 1 week (T1) and 6 months (T2) postoperatively were superimposed to measure surgical movements (T0-T1) and skeletal relapse (T1-T2). The distorted dentition of the CBCT scans at T1 was replaced with 3D images of the dental models to assess the postoperative occlusion. Surgical movements of the maxilla (mean ± standard deviation values) were 6.79 ± 2.30 mm advancement, 1.28 ± 1.09 mm vertically, and 0.71 ± 0.79 mm mediolaterally. Horizontal rotation (yaw) was 1.56° ± 1.21°, vertical rotation (pitch) 1.86° ± 1.88°, and tilting (roll) 1.63° ± 1.54°. At T2, the posterior relapse was 0.72 ± 0.43 mm (P = 0.001) and relapse in pitch was 1.56° ± 1.42° (P = 0.007). There was no correlation between the size of the surgical movements and the amount of relapse. A weak correlation was noted between the number of teeth in occlusal contact immediately following surgery and relapse of maxillary roll (r = - 0.434, P = 0.030). The stability of maxillary advancement with the surgery-first approach was satisfactory and was not correlated with the quality of the immediate postoperative occlusion.

Three-dimensional evaluation of skeletal stability after surgery-first bimaxillary surgery for class III asymmetry in 70 consecutive patients

Background/purpose

Skeletal stability after orthognathic surgery is essential for positive treatment outcome. This study evaluated the stability of osteotomy segments after surgery-first bimaxillary surgery for class III asymmetry.

Materials and methods

Seventy adults with class III asymmetry consecutively corrected through surgery-first Le Fort I and bilateral sagittal split osteotomies were investigated. Cone-beam computed tomography before treatment (T0), 1-week after surgery (T1), and after all treatment (T2, ≥1-year after surgery) was used to assess surgical movement (T0 to T1) and skeletal stability (T1 to T2) regarding the translation and rotation of the maxillary, mandibular distal, and proximal segments.

Results

At T1, the maxillary segment had moved forward and upward, turned to the deviated side, and rotated downward (all P < 0.01). The distal segment of mandible had moved forward and upward and rotated upward (all P < 0.001). The deviated proximal segment had moved upward, tilted to the opposite side, and rotated upward (all P < 0.001). The opposite proximal segment had moved upward and tilted to the deviated side (both P < 0.01). At T2, significant relapse occurred in the mandible. The distal segment moved forward and upward and rotated upward (all P < 0.001). The deviated proximal segment moved upward, tilted to the opposite side, and rotated upward (all P < 0.001). The opposite proximal segment moved upward and tilted to the deviated side (both P < 0.01).

Conclusion

Clinically significant relapse of class III asymmetry was discovered on the mandibular distal and opposite proximal segments.

Three-dimensional analysis of mandible ramus morphology and transverse stability after intraoral vertical ramus osteotomy

Objectives

The purpose of this study was to investigate short- and long-term postoperative changes of both morphology and transverse stability in mandibular ramus after intraoral vertical ramus osteotomy (IVRO) in patients with jaw deformity using three-dimensional (3D) orthognathic surgery planning treatment software for measurement of distances and angles.

Study design

This retrospective study included consecutive patients with skeletal Class III malocclusion who had undergone intraoral vertical ramus osteotomy and computed tomography images before (T0), immediately after (T1), and 1 year after (T2) surgery. Reference points, reference lines and evaluation items were designated on the reconstructed 3D surface models to measure distances, angles and volume. The average values at T0, T1, T2 and time-dependent changes in variables were obtained.

Results

After surgery, the condylar length, ramal height, mandibular body length and mandibular ramus volume were significantly decreased (P < 0.01), while clinically insignificant change was observed from T1 to T2. The angular length was increased immediately after surgery (P < 0.05), but it was decreased 1 year after surgery (P < 0.05). Lateral ramal inclination showed significant increase after surgery (P < 0.05) and maintained at T2.

Conclusion

Changes in the morphology of the mandibular ramus caused by IVRO do not obviously bring negative effect on facial appearance. Furthermore, despite position and angle of mandibular ramus changed after IVRO, good transverse stability was observed postoperatively. Therefore, IVRO technique can be safely used without compromising esthetic results.

Ramal inclination in the frontal plane after bimaxillary orthognathic surgery in skeletal class III facial asymmetry : Spontaneous changes and stability

PURPOSE

This study aimed to observe spontaneous changes of ramal inclination in the frontal plane (FRI) and its stability in skeletal class III asymmetry patients corrected with bimaxillary surgery. The correlation between FRI change and surgical skeletal change was also investigated.

METHODS

Forty-nine patients with skeletal class III facial asymmetry who underwent orthognathic surgery with at least 1° change in FRI after surgery were analyzed. FRI and other factors were measured on frontal and lateral cephalograms before surgery (T1), after surgery (T2), and at follow-up after at least 6 months (T3). Correlation analysis was performed to determine pre- and postoperative factors associated with FRI change and stability.

RESULTS

FRI increased significantly on the deviated side and decreased on the nondeviated side after surgery. The FRI changes remained stable during follow-up. No correlation between FRI changes and skeletal changes during surgery were found except between the change of FRI during follow-up (T3-T2) and mandibular setback amount (T2-T1), with a weak coefficient of 0.32.

CONCLUSION

The FRI changes after bimaxillary orthognathic surgery in skeletal class III asymmetry reduced the FRI difference between the deviated and nondeviated side and remained stable for at least 6 months after surgery. No clinically significant correlation was found between measured skeletal changes during surgery and FRI changes.

Long-term dental stability after orthognathic surgery: a systematic review

BACKGROUND

Long-term dental stability is one of the main objectives following combined orthodontic and orthognathic surgical treatment. It is influenced by multiple factors such as surgical, patient-related, and orthodontic aspects. While recent reviews mainly focus on short-term dental changes (0.5-2 years), longer follow-up dental stability remains hardly reviewed.

OBJECTIVES

The aim of this study was to evaluate long-term stability of dental and dentolabial changes following combined orthodontic and orthognathic surgical treatment with a minimum follow-up period of 5 years.

SEARCH METHODS

A systematic search was conducted up to December 2019 using Pubmed, Embase, Web of Science, and Cochrane Central.

SELECTION CRITERIA

Randomized controlled trials (RCTs), prospective and retrospective cohort studies, and case series with a minimum of 10 patients, which reported long-term dental stability following combined orthodontic and orthognathic treatment, were included.

DATA COLLECTION AND ANALYSIS

Long-term changes were assessed for overjet, overbite, maxillary, and mandibular incisors' position and relationship of lip position to maxillary and mandibular incisors. Risk of bias was assessed according to the Cochrane Handbook.

RESULTS

Following the screening of 3178 articles, 11 studies were included (2 RCT, 9 retrospective) with a postoperative follow-up period ranging from 5 to 15 years. A decrease in overjet was observed for patients with skeletal class III malocclusion, whereas overjet increased in class II patients at long-term follow-up. Overbite increased in class II patients, whereas class III showed variable results. The lower incisor position was more stable vertically than horizontally; the latter showing more outcome variability. Dentolabial changes corresponded to the normal ageing process and results were not clinically significant after long-term follow-up.

CONCLUSION

Current evidence suggests variability of dental and dentolabial stability in both skeletal class II and III patients. Further prospective studies are required to develop guidelines for long-term follow-up assessment using computer tomography or cone-beam computed tomography imaging, before final conclusions can be drawn.

REGISTRATION

The protocol for this systematic review (CRD42020133844) was registered in the International Prospective Register of Systematic Reviews (PROSPERO).

Surgery-first orthognathic approach for the correction of facial asymmetry

We aimed to compare the reliability of the surgery-first approach and the traditional orthodontic-first approach for the correction of facial asymmetry based on the new classification of facial asymmetry. Patients with facial asymmetry who underwent orthognathic surgery between January 2016 and January 2019 were included. Cephalometric changes and relapse ratios were analyzed 12 months before and after surgery. Patients were divided into horizontal and vertical asymmetry groups based on the asymmetry vector, and subgroup analysis was conducted. The surgery-first approach without presurgical orthodontic treatment and the orthodontic-first approach showed a similar degree of asymmetry correction and skeletal stability. The relapse ratios of the maxilla height in the surgery-first and orthodontic-first groups were 0.25 ± 0.21 and 0.27 ± 0.25, respectively (p = 0.63), the relapse ratios of the maxilla width were 0.31 ± 0.32 and 0.21 ± 0.2, respectively (p = 0.14), the mandibular height relapse ratios were 0.34 ± 0.58 and 0.29 ± 0.36, respectively (p = 0.69), and the mandibular width relapse ratios were 0.12 ± 0.22 and 0.26 ± 0.31, respectively (p = 0.058). The treatment period of the surgery-first group (18.5 ± 5.3 months) was significantly shorter than that of the orthodontic-first group (22.9 ± 7.5 months, p = 0.024). Among the surgery-first group, patients with vertical asymmetry (15.0 ± 3.2 months) had a shorter treatment than those with horizontal asymmetry (21.6 ± 6.8 months, p = 0.006). Although contesting traditional standards is always challenging, the surgery-first orthognathic approach may lead to a new era in traditional orthognathic approaches. This new classification of facial asymmetry could be useful and practical when treating patients with facial asymmetry regardless of the etiology.

Maintaining the space between the mandibular ramus segments during bilateral sagittal split osteotomy does not influence the stability

BACKGROUND/PURPOSE

Three-dimensional computer-assisted orthognathic surgery allows to simulate the space between the mandibular ramus segments, i.e. intersegmental gap, for the correction of facial asymmetry. The purposes of the study were to estimate the screws- and mandible bone-related changes from the early postoperative period to the period after the debonding and to measure the association between the intersegmental gap volume and the screws- and mandible bone-related changes.

METHODS

This cone-beam computed tomography (CBCT)-assisted retrospective study assessed the stability of the bicortical positional screw fixations in maintaining the space between the mandibular ramus segments after bilateral sagittal split osteotomy in correction of 31 patients with malocclusion and facial asymmetry. The primary predictor variable was the CBCT-based intersegmental gap volume at early postoperative period (T1). The primary outcome variables were CBCT-based screws- and bone-related measurement changes between the T1 and T2 (at debonding) periods.

RESULTS

No significant differences were observed in screws-related linear and angular measurements between T1 and T2 virtual models. Some of mandible bone-related linear and angular measurements had significant differences (P < 0.05) between the T1 and T2 images, but with no clinical repercussion such as need of revisionary surgery. The gap volume and the screws- and bone-related changes had no significant correlations.

CONCLUSION

This study contributes to the multidisciplinary-related literature by demonstrating that the bicortical positional screws-based fixation technique in maintaining the three-dimensional-simulated space between the mandibular ramus segments is a stable and clinically acceptable option for correction of facial asymmetry associated with malocclusion, regardless of intersegmental gap size.

Comparative stability and outcomes of two surgical approaches for correction of class III asymmetry with lip or occlusal cant

OBJECTIVES

To assess and compare the stability and outcomes of the two surgical approaches for patients with roll asymmetry.

MATERIALS AND METHODS

A total of 50 adult patients were consecutively recruited for this prospective study. Patients with class III asymmetry and lip or occlusal cant who underwent bimaxillary surgery were grouped according to surgical approach: asymmetric posterior impaction on both sides (API, n = 31) and posterior impaction on one side and posterior extrusion on the other side (PIE, n = 19). Postsurgical stability and outcomes between groups were determined with cone-beam computed tomography for facial midline, lip, and occlusal cant at 1 week (T1), and at least 12-month postsurgery (T2, completion of orthodontic treatment).

RESULTS

Presurgery, the upper anterior occlusal cant and lip cant were significantly greater for the PIE group (p < 0.05). Postsurgery (T2), the mandible moved upward and rotated upward in both groups. However, the upward rotation was significantly greater in the PIE group compared with the API group. Although the two approaches resulted in significant improvements in facial symmetry, the deviation in the facial midline remained under-corrected for most API patients.

CONCLUSIONS

Patient outcomes for mandibular stability and facial symmetry differed between the two surgical approaches for correction of class III asymmetry with lip or occlusal cant.

CLINICAL RELEVANCE

The findings of this study suggest that planned over-correction is a reasonable option for the approach of asymmetric posterior impaction on both sides.

Does a surgery first approach to orthognathic treatment of class III skeletal relations result in a shorter duration of treatment? A systematic review

The objective of this study was to review the evidence relating to treatment duration and the surgery first approach (SFA) in managing class III skeletal discrepancies to determine whether there is sufficient evidence to show that it results in a shorter duration of treatment compared to a conventional orthodontics first approach (OFA). Analytical and observational studies that compared both approaches and recorded treatment duration as an outcome were included. MEDLINE, EMBASE, CENTRAL and Dental Oral Sciences Source databases were searched along with a review of reference lists. Risk of bias was assessed using the Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) tool. Eleven observational studies met the inclusion criteria. No experimental studies were identified. The SFA was reported to have a shorter duration of treatment in all studies. All included studies showed a significant risk of bias, particularly in relation to selection of participants, allocation to groups and in the measurement of treatment duration. There is no quality evidence to suggest that using a surgery first approach to orthognathic treatment of class III skeletal patterns results in a shorter duration of treatment.

Surgery-first orthognathic approach vs conventional orthognathic approach: A systematic review of systematic reviews

Surgery-first approach (SFA) has been introduced as an alternative for conventional orthognathic approach (COA) in the treatment of patients with dentoskeletal deformities. This review aimed to evaluate skeletal stability, treatment time, surgical complications, and quality of life in SFA and COA. Six databases were accessed up to May 2020 to obtain all systematic reviews (SRs). After title and abstract reading, data extraction was performed from eligible SRs. The methodological quality was calculated for the included SRs using the last version of A Measurement Tool to Assess Systematic Review (AMSTAR-2). Ten SRs were included in this review. A good stability of the jaws was assessed both with SFA and COA by most of low- or critically low-quality SRs. Less treatment time was reported for SFA than COA with a moderate quality level. Slightly higher complications rate was recorded with SFA than COA by SRs with low or moderate quality. A better quality of life with SFA than COA was reported by moderate- or low-quality SRs. SFA may represent a reasonable alternative to COA. However, for the heterogeneity of the included SRs, well-designed studies with a long term follow-up are needed to clarify the findings of this analysis.

Changes in the temporomandibular joint clicking and pain disorders after orthognathic surgery: Comparison of orthodontics-first approach and surgery-first approach

The purposes of this study were to investigate the influence of the orthodontics-first approach (OFA) and surgery-first approach (SFA) on changes in the signs and symptoms of temporomandibular joint disorders (TMDs) and to compare pre- and postoperative orthodontic treatment duration and total treatment duration between the two approaches. This retrospective study recruited 182 adult patients with malocclusions treated with OFA and SFA and recorded variables such as age, gender, skeletal classification, and signs and symptoms of TMD (clicking and pain disorders) before the start of the surgical-orthodontic treatment and after surgery. Changes in the signs and symptoms of TMD and treatment duration were evaluated within each approach and compared between two approaches. A binary logistic regression was performed to assess the influence of the variables on the postoperative signs and symptoms of TMD. There were no significant postoperative changes in temporomandibular joint (TMJ) pain for OFA and SFA, whereas a significant reduction was found in TMJ clicking after surgery for both approaches. According to binary logistic regression, the type of surgical-orthodontic treatment (OFA or SFA) was not a significant risk factor for postoperative TMJ clicking and pain, and the risk of postoperative TMJ clicking and pain was significant only when TMJ clicking (OR = 10.774, p < 0.001) and pain (OR = 26.876, p = 0.008) existed before the start of the entire treatment, respectively. With regard to the treatment duration, SFA (21.1 ± 10.3 months) exhibited significantly shorter total treatment duration than OFA (34.4 ± 11.9 months) (p < 0.001). The results of this study suggest that surgical-orthodontic treatment using SFA can be a feasible option of treatment for dentofacial deformities based on the equivalent effect on TMD and shorter overall treatment period compared to conventional surgical-orthodontic treatment using OFA.

Facial asymmetry correction: From conventional orthognathic treatment to surgery-first approach

The surgery-first approach (SFA), which proceeds without presurgical orthodontic treatment, is assumed to shorten the treatment course because the direction of post-surgical orthodontic tooth movement conforms to the normal muscular forces. Moreover, the regional acceleratory phenomenon (RAP), evoked by surgery, helps in tooth alignment and compensation in a faster way. Although SFA has definite advantages, especially in class III individuals, there is a lack of data about its indications in patients with facial asymmetry. In this article, we reviewed recently published articles on the treatment of asymmetric patients using the SFA. Different aspects, including the three-dimensional assessment of stability in different planes, approaches for fabrication of a surgical splint, predictability of the results, skills needed for bimaxillary surgery, indications as the treatment of choice for condylar hyperplasia, and combination with distraction osteogenesis in candidates with severe asymmetries were found to be the main topics discussed for patients presenting with facial asymmetry

Surgery-first orthognathic approach: A “scoping review” for mapping outcomes and plausible recommendations to develop core outcome sets

Aims and Objectives

The aim of this scoping review was to identify the type of outcomes measured in surgery- first orthognathic approach (SFOA). The objectives were to classify the outcomes into predetermined domains and explore the degree of representation of each domain. Furthermore, to identify which domains are over- or under-represented and determine whether the findings of this scoping review could be employed to provide a template for core outcome sets (COS). Five outcomes were identified, and all the research pertinent to SFOA were assigned to these outcomes.

Materials and Methods

Electronic databases and additional records were searched from January 2009 to March 2019 to source the data, and 525 records were identified.

Results

The initial database and additional search resulted in 525 records, of which 54 potentially relevant articles were retrieved in full. 35 studies met the selection criteria following screening and were included in the scoping review with the results of the search depicted in the preferred reporting items for systematic reviews and meta-analyses. Domains such as morphological features or changes in maxillofacial skeleton and occlusion (n = 25, 71.42%) and psychosocial well-being including quality of life outcome (n = 8, 22.85%) were well represented while functional status (n = 1, 2.85%), health resource utilization (n = 0), and adverse effects (n = 1, 2.85 %) were under-represented.

Conclusions

Limited research on SFOA precludes development of COS. However, future SFOA clinical trials should consider underrepresented outcome domains to address the SFOA treatment modality comprehensively.