“…For this reason, the A point was only used in the evaluation of the relapse in the anteroposterior dimension. Similar difficulties in identifying ANS and A points have been reported by earlier investigators (Venkategowda et al, 2017). The rationale and the effect of sub-spinal osteotomy on soft-tissue changes in the nasal area were analysed earlier (Mommaerts et al, 2000) but to our knowledge no comparative analysis of conventional Le Fort I osteotomy exists.…”
Background: Three-dimensionally (3D) designed osteotomies and customised osteosynthesis are rapidly becoming standard in maxillofacial reconstructive and deformity surgery. Patient-specific implants (PSIs) have been in use for a few years in orthognathic surgery as well. In Le Fort I osteotomy, wafer-free fixation of the maxillary segment can be performed by individually manufactured cutting and drill guides together with PSIs. Aim: This retrospective study was performed to compare the postoperative skeletal stability of the maxillary segment fixed by patient-specific implants versus mini-plates after Le Fort I osteotomy. Patients: Fifty-one patients were divided into subgroups according to the fixation method and the advancement of the sub-spinal point. The postoperative skeletal stability of the maxillary segment was evaluated from lateral cephalometric radiographs one year postoperatively. Results: No statistically significant differences were found between the postoperative skeletal stability of the PSI and mini-plate fixed maxillae. Prospective studies, possibly with 3D fusion analysis, are warranted to confirm the results. Conclusion: The choice between the two fixation methods does not seem to affect the postoperative skeletal stability of the maxillary segments.
“…For this reason, the A point was only used in the evaluation of the relapse in the anteroposterior dimension. Similar difficulties in identifying ANS and A points have been reported by earlier investigators (Venkategowda et al, 2017). The rationale and the effect of sub-spinal osteotomy on soft-tissue changes in the nasal area were analysed earlier (Mommaerts et al, 2000) but to our knowledge no comparative analysis of conventional Le Fort I osteotomy exists.…”
Background: Three-dimensionally (3D) designed osteotomies and customised osteosynthesis are rapidly becoming standard in maxillofacial reconstructive and deformity surgery. Patient-specific implants (PSIs) have been in use for a few years in orthognathic surgery as well. In Le Fort I osteotomy, wafer-free fixation of the maxillary segment can be performed by individually manufactured cutting and drill guides together with PSIs. Aim: This retrospective study was performed to compare the postoperative skeletal stability of the maxillary segment fixed by patient-specific implants versus mini-plates after Le Fort I osteotomy. Patients: Fifty-one patients were divided into subgroups according to the fixation method and the advancement of the sub-spinal point. The postoperative skeletal stability of the maxillary segment was evaluated from lateral cephalometric radiographs one year postoperatively. Results: No statistically significant differences were found between the postoperative skeletal stability of the PSI and mini-plate fixed maxillae. Prospective studies, possibly with 3D fusion analysis, are warranted to confirm the results. Conclusion: The choice between the two fixation methods does not seem to affect the postoperative skeletal stability of the maxillary segments.
“…After duplicate removal and screening of titles or abstracts against the predefined eligibility criteria (Additional file 1 : Appendix 3) the full texts of 300 papers were checked. Finally, 4 papers pertaining to 4 unique studies (4 retrospective non-randomized studies), which were published as journal papers, were included [ 12 , 15 , 19 , 21 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The studies were conducted in university hospitals (n = 4) and in one study additionally in private practices and originated from four different countries: Brasil, India, USA, Finland [ 12 , 15 , 19 , 21 ]. A total of 132 (range 10 to 50) patients were included, which does not exactly correspond to the total number of participants in the primary studies, because only Angle Class II patients were taken into consideration for this review.…”
Section: Resultsmentioning
confidence: 99%
“…Two of the included studies explicitly assessed single jaw interventions [ 15 , 19 ] and two explicitly bimaxillary interventions [ 12 , 19 ], whereas one of them did not differentiate patients with maxillary intervention only and patients with a bimaxillary procedure [ 21 ]. The evaluated interventions consisted of mandibular advancement surgery by bilateral sagittal split osteotomy, maxillary impaction by LeFort I osteotomy and bimaxillary procedures, which combined both.…”
Objectives
Relapse after orthognathic surgery seems to depend on diverse factors. Proffit et al. postulated in 2007 a “hierarchy of stability” (Head Face Med 6:66, 2007), ranking posttreatment stability after various orthognathic procedures, but no systematically reviewed evidence was provided. Therefore, the aim of this review was to investigate the extent of class II relapse in orthognathic surgery of Angle class II patients depending on the surgical procedure used.
Materials and methods
Seven databases were searched for randomized and controlled clinical trials to compare relapse in surgical procedures for Angle class II patients. After duplicate study selection, data extraction and risk of bias assessment were performed with the ROBINS-I tool as well as data synthesis by frequency distribution, followed by assessment of the quality of evidence with GRADE.
Results
Four non-randomized cohort-studies with a total of 132 patients were included. Bimaxillary procedures as well mandibular advancement procedures proved to be highly stable. Single jaw interventions at the maxilla achieved mostly stable results at sagittal dimension and problematic stability in the vertical dimension. However, there were only limited data available with low quality of evidence.
Conclusions
Limited existing evidence of low quality partly support the postulated hierarchy of stability of Proffit et al. (Head Face Med 6:66, 2007) and indicates that a surgical correction of class II dysgnathia with bimaxillary procedures and mandibular advancement seems to be highly stable. However, additional studies are needed to address the relation between relapse and surgical orthognathic intervention.
Trial registration PROSPERO 2019 CRD42019144873.
“…First, the mean errors of ANS were different among the four time-points (T0, 1.07 mm; T1, 1.22 mm; T2, 1.78 mm; T3, 1.49 mm; p < 0.01, Table 4) and presented an increased error value after TJ-OGS than before it ([T0, T1] vs. [T2, T3]; p < 0.01, Table 4). This suggested that the metal image of the SP-S adjacent to ANS as well as surgical shape modification of ANS 19,20 (Figure 1) could affect the accuracy of AI-assisted landmark detection. Second, although the error of A point was not significantly different among the four time-points (T0, 1.27 mm; T1, 1.28 mm; T2, 1.50 mm; T3, 1.59 mm; Table 4), it presented an increase in the mean error value after TJ-OGS than before it ([T0, T1] vs. [T2, T3]; p < 0.05, Table 4).…”
Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent twojaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four timepoints (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.
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