Long-term Skeletal Stability of Mandibular Surgery with Bilateral Sagittal Split Ramus Osteotomy—Advancement Versus Setback: A Systematic Review and Meta-analysis
Bibliographic record
Abstract
Objectives The aim of this study was to evaluate and compare the long-term skeletal stability of mandibular advancement and mandibular setback achieved with bilateral sagittal split ramus osteotomy (BSSRO) procedure in adult patients with a minimum follow-up of at least 1 year. Methods A literature search was systematically performed according to PRISMA guidelines from four databases without limitation till 15 June 2021. Available literature was assessed for long-term skeletal stability as horizontal/vertical changes at cephalometric point B following conventional mandibular surgery (BSSRO) with rigid internal fixation. The quality of selected articles was assessed using Newcastle–Ottawa scale and the meta-analysis was carried out with Q statistic method, I-squared statistics, and fixed-effect model to estimate the pooled mean and Begg–Mazumdar bias indicator. Results A total of five studies (three pertaining to mandibular advancement and two setback groups) were included for comparative evaluation of relapse. The mean horizontal relapse was 7.85% pertaining to mandibular advancement (4.2–7.06 mm) as compared to 27% pertaining to mandibular setback (7.18–10.26 mm). The meta-analysis of four included studies (two in each group) revealed significant differences in long-term skeletal stability of mandibular advancement and setback (pooled proportion = 20.10; 95% confidence interval = 2.48–39.57). Conclusion Mandibular setback can be expected to relapse by 21.7–32.3% (mean 27%) as compared to mandibular advancement accounting for a relapse of 2.1–15.4% (mean 7.85%) in adult patients. Hence, mandibular advancement is a relatively stable procedure in the long term. PROSPERO registration number: CRD42021261466
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.010 | 0.021 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.015 | 0.031 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".