Objective The aim of this study was to assess the operation time, shear bond strength, placement accuracy and wear resistance of 3 composite materials (Filtek Z350XT, Filtek Z350XT Flowable and SonicFill) that were used to make attachments for clear aligners. Settings and sample population Laboratory of Stomatology of Shanghai Ninth People’s Hospital affiliated to Shanghai Jiao Tong University School of Medicine. A total of 129 human mandibular premolars were collected, 69 of which were assigned to 3 groups (A1, B1 and C1). The remaining 60 teeth were divided into 3 groups (A2, B2 and C2). Methods Z350XT composite resin was used in groups A1 and A2 to bond the attachments. Z350XT Flowable composite resin was used in groups B1 and B2. SonicFill composite resin was used in groups C1 and C2. The operation time, shear bond strength, the placement accuracy and wear volume loss of 3 composite materials were evaluated. Results The operation time of Z350XT Flowable and SonicFill was shorter than Z350XT (P < .05). The shear bond strength of SonicFill was higher than Z350XT and Z350XT Flowable (P < .05). The SEM showed that the bonding interface of Z350XT and SonicFill was compact. The 3D deviation and volumetric change in the 3D designed attachments and the attachments after actual bonding of Z350XT Flowable were greater than that of Z350XT and SonicFill (P < .05). The wear volume loss of SonicFill and Z350XT was less than that of Z350XT Flowable (P < .05). Conclusion SonicFill seems to represent a suitable material for producing attachments, which optimized the property combination.

Background The aim of the study was to analyze the morphology and position of the tongue and hyoid bone in skeletal Class II patients with different vertical growth patterns by cone beam computed tomography in comparison to skeletal Class I patients. Methods Ninety subjects with malocclusion were divided into skeletal Class II and Class I groups by ANB angles. Based on different vertical growth patterns, subjects in each group were divided into 3 subgroups: high-angle group (MP-FH ≥ 32.0°), average-angle group (22.0° ≤ MP-FH < 32°) and low-angle group (MP-FH < 22°). The position and morphology of the tongue and hyoid bone were evaluated in the cone beam computed tomography images. The independent Student’s t‐test was used to compare the position and morphology of the tongue and hyoid bone between skeletal Class I and Class II groups. One-way analysis of variance (ANOVA) was used to compare the measurement indexes of different vertical facial patterns in each group. Results Patients in skeletal Class II group had lower tongue posture, and the tongue body was smaller than that of those in the Class I group (P < 0.05). The position of the hyoid bone was lower in the skeletal Class II group than in Class I group (P < 0.05). The tongue length and H-Me in the skeletal Class I group with a low angle were significantly larger than those with an average angle and high angle (P < 0.05). There was no significant difference in the position or morphology of the tongue and hyoid bone in the skeletal Class II group with different vertical facial patterns (P > 0.05). Conclusion Patients with skeletal Class II malocclusion have lower tongue posture, a smaller tongue body, and greater occurrence of posterior inferior hyoid bone position than skeletal Class I patients. The length of the mandibular body in skeletal Class I patients with a horizontal growth type is longer. The position and morphology of the tongue and hyoid bone were not greatly affected by vertical facial development in skeletal Class II patients.

Background The aim of this study was to present comprehensive skeletal, dental and facial aesthetic outcomes and long-term stability of maxillary anterior segmental distraction osteogenesis (MASDO) for the treatment of maxillary hypoplasia in CLP. Materials and methods Six patients with maxillary hypoplasia treated with MASDO by a miniscrew assisted intraoral tooth-borne distractor were included. Cephalometric radiographs were obtained before distraction (T1), after the consolidation period (T2) and after orthodontic treatment or before orthognathic surgery (T3). Thirty-one cephalometric variables (12 skeletal, 9 dental, and 10 soft tissue variables) were used to evaluate changes in the dentofacial structures and the soft tissue profile. Friedman and Wilcoxon tests were applied to identify significant differences in hard and soft tissue changes during the T1–T2, T2–T3, and T1–T3 periods. Results All patients successfully underwent MASDO without serious complications. From T1 to T2, forward movements of ANS and A (FH ⊥ N–A, VRL–ANS and VRL–A) were significant (p < 0.05). Significant increases in SNA and ANB were noted. Significant upward movement of points ANS (CFH–ANS) and A (CFH–A) was observed (p < 0.05). After distraction, a significant decrease in overjet and an increase in overbite were obtained (p < 0.05). Anterior tipping of the upper incisors (U1/ANS–PNS and U1/SN) was observed (p < 0.05). The soft tissue points of Pn, Sn, Ss, and ls showed significant anterior movement (p < 0.05). In addition, a significant increase in the nasolabial angle was measured (p < 0.05). All of the above data showed no statistically significant changes between T2 and T3 (p > 0.05). Conclusion MASDO using a miniscrew assisted tooth-borne distractor presented significant maxillary advancement and favorable long-term stability in treating CLP patients with maxillary hypoplasia.