Methods: 14 CLP patients (9 unilateral, 5 bilateral) had CBCT images taken at initial (T1), post-expansion (T2), six-month post-graft (T3), and one-year post-graft (T4) time-points. Volumetric and linear measurements were performed and compared for statistical significance at each time-point. Treatment methods and expansion/relapse were analyzed for significant correlations.
Results: The mean cleft volume increased 29.5% from T1 to T2 with greater expansion seen in unilateral CLP (39.9%). Significantly increased three-dimensional relapse was found at T4 (47.9%) from T3 (24.2%) and bilateral cases exhibited greater relapse. The anterior region relapsed a significantly greater amount (34.1%) while the posterior relapsed 17.6% linearly. There was significant positive correlation between the placement of transpalatal arch with anterior extensions and decreased anterior relapse (r=0.77). Compared to linear measurements, volumetric analyses resulted in 10.1% more expansion and 3.5% more relapse.
Conclusion: As a greater amount of relapse occurred in the anterior region, a retention protocol with anterior support may be clinically superior in minimizing post-expansion relapse and improving treatment outcomes for CLP patients. Our study also suggests that linear measurements used in previous studies underestimate the actual amount of expansion and relapse in CLP patients. A volumetric analysis can provide a more accurate representation of the physiologic changes and this study provides a protocol to obtain that volumetric analysis for future studies.