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, Mais Sadek , Ahmad M. Hamdan Abstract : Objective: This study aimed to compare the predicted and achieved labiolingual inclinations of the maxillary central incisors in adult Class II division 2 malocclusions treated with clear aligners using Power Ridges® and composite attachments. Methods: This retrospective study included 24 patients (mean age, 26.5 ± 3.3 years). The patients had Class II division 2 malocclusion and were treated with non-extraction with Invisalign® clear aligners with either Power Ridges® or composite attachments to enhance the predictability of required change in labiolingual inclination for the maxillary central incisors. Before treatment, treatment prediction and final digital models were exported as stereolithography files and superimposed using the eModel 9.0 “Compare” software. The predicted and achieved labiolingual incisor inclinations were compared. Results: The mean accuracies of the achieved inclination of the central incisors were 68.3% in the Power Ridges® group and 71.6% in the attachments group. No statistically significant differences in predictability were found between the groups (P > 0.05). A low positive correlation was observed between the predicted inclination change and the average absolute difference between the predicted and achieved inclinations (r = 0.19). Conclusions: Predicted labiolingual inclination is not fully achieved with clear aligners in both the Power Ridges® and attachment groups. Clinicians must take measures to counteract this limitation, specifically in Class II division 2 cases.
, Jung-Jin Park , Jin Bai , Seong-Hun Kim Abstract : Objective: Miniscrew-assisted maxillary expansion devices are frequently used for patients with calcified midpalatal sutures. This study aimed to evaluate the effects of two bone-borne maxillary expansion appliances on the cranial and circummaxillary sutures by comparing cone-beam computed tomography (CBCT) images before and after transverse maxillary expansion. Methods: A total of 81 patients (women = 58, men = 23) were treated with either a C-expander (n = 44) or an ATOZ expander (n = 37). CBCT images were obtained before (T0) and after (T1) maxillary expansion, and the widths of 10 circummaxillary sutures were measured in the sagittal, coronal, and axial planes. The Wilcoxon signed-rank test was used to compare the changes in suture width between the C-expander and ATOZ groups, and statistical significance was set at P < 0.05. Results: The frontonasal, frontomaxillary, pterygomaxillary, nasomaxillary, internasal, intermaxillary, and midpalatal suture widths increased significantly after maxillary expansion in both the ATOZ and C-expander groups (both P < 0.05). The frontozygomatic, zygomaticomaxillary, and temporozygomatic suture widths decreased in the C-expander group (P < 0.05), whereas the frontozygomatic suture width increased significantly in the ATOZ group (P < 0.05). The width changes of the frontozygomatic, zygomaticomaxillary, temporozygomatic, pterygomaxillary, internasal, intermaxillary, and midpalatal sutures differed significantly between the two groups (P < 0.05). Conclusions: Both the C- and ATOZ expanders affected the suture width in the naso-maxillo-zygomatic region. The C-expander decreased the circum-zygomatic suture widths, whereas the ATOZ expander widened the frontozygomatic suture with no effect on other circummaxillary sutures.
, Jin-Woo Lee Abstract : Objective: To measure and compare the extent of root resorption in the maxillary incisors following microimplant-assisted rapid palatal expansion (MARPE) and to identify risk factors of root resorption after expansion. Methods: Cone-beam computed tomography images were obtained from a total of 60 patients both before expansion (T1) and 3 to 6 months after expansion (T2). Measurements taken included tooth length, root length, crown length and center of resistance. Resorption length (RL) and resorption length percentage (RLp), resorption volume (RV) and resorption volume percentage (RVp) and the amount of expansion were calculated. Results: A significant difference in tooth length and volume was observed in both the central and lateral incisors before and after expansion. The resorption index (RL, RLp, RV, RVp) was significantly higher in the central incisors than in the lateral incisor. There was a significant correlation between several factors: age and RLp of the central incisors, the amount of expansion and RVp of the central incisors, tooth length of the central incisors and RL, RLp of the central incisors, root/crown ratio of the central incisors and RL of the central incisors, as well as tooth length of the lateral incisors and the RL of the lateral incisors. Conclusions: Significant root resorption occurs in maxillary incisors following MARPE, with central incisors root resorption being significantly higher than lateral incisors. Key risk factors for root resorption after MARPE include advanced age, a larger amount of expansion, initial tooth length, and a root/crown ratio.
2.6
2023 IF
