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Objectives Carriere Motion 3D™ appliance (CMA) represents a method for molar distalization and correction of class II malocclusion. The aim was to investigate the 3D effects of the CMA by superimposing digital models and cephalometric X-rays. Materials and methods We retrospectively examined 16 patients treated with CMA in combination with class II elastics. We compared digitized models and cephalometric X-rays of records taken before therapy and after the removal of CMA. The records were superimposed to assess the skeletal and dentoalveolar changes. The results of the cephalometric X-ray analysis were compared to an untreated age- and gender-matched sample. Results Class II occlusion was corrected after 11.85 ± 4.70 months by 3.45 ± 2.33 mm. The average distalization of the upper first molars was 0.96 ± 0.80 mm. The analysis of the cephalometric X-rays confirmed a distalization of the upper first molars with distal tipping and revealed a mesialization of the lower first molars of 1.91 ± 1.72 mm. Importantly, CMA resulted in a mild correction of the skeletal class II relationship (ANB: − 0.71 ± 0.77°; Wits: − 1.99 ± 1.74 mm) and a protrusion of the lower incisors (2.94 ± 2.52°). Compared to the untreated control group, there was significant distalization of the upper first molars and canines with mesialization and extrusion of the lower first molars. Conclusion and clinical relevance CMA is an efficient method for treating class II malocclusions. However, the class II correction is only partially caused by a distalization of the upper molars.

Objective: The objective of this study was to assess the accuracy of physical reproductions of plaster orthodontic study casts fabricated by two different rapid prototyping techniques: Fused Deposition Modeling (FDM) and Digital Light Processing (DLP).Materials and methods: Twenty pairs of pretreatment plaster models were prepared from randomly selected patients at the Orthodontic Department, University of Damascus Dental School. Twenty-one reference points were placed on plaster models, followed by scanning and printing of these models using FDM and DLP techniques. Forty measurements were made on these models using a digital caliper. Paired t tests were used to detect significant differences in the measurements between the 3D printed replicas and the original plaster models (Gold Standard). Alpha level was adjusted due to the multiplicity of the tests. Results:The intraclass correlation coefficients for all the comparisons made between the 3D replicas and the gold standard models were greater than 0.80 with ICCs ranging from 0.802 to 0.990 and from 0.853 to 0.990 for the FDM and DLP techniques, respectively. This indicated an excellent agreement. No statistically significant differences could be detected between the 3D-printed models and their corresponding plaster models. The overall mean difference was −0.11 mm and 0.00 ranging from −0.49 to 0.17 mm and from −0.42 to 0.50 mm, for the FDM and DLP techniques, respectively. Conclusion:The accuracy of the 3D models produced by the DLP and FDM techniques was acceptable. However, for the fabrication of clear aligners, the optimum fit of the produced plates in the patients' mouths is not completely guaranteed.

Objective: The goal of the study was to examine the strain in the sutures of the midface and the cranial base with maxillary protraction therapy and to clarify whether such stretching suggests a skeletal effect of the apparatus employed for that purpose. Materials and Methods: Using a finite elements model, a maxillary protraction therapy was simulated with various force levels and vectors, and the strains appearing at the sutures (in strain) were measured at the midface and the cranial base. The simulation model we employed consisted of 53,555 individual elements; the simulated forces were 2 ϫ 3 N and 2 ϫ 5 N, while the vectors of the applied forces were in the anterior and anterior caudal direction. Results:The maximum measured strains were on average below 10 strain, while higher values were measured only at the nasal bone and at the cranial base at the oval and spinous foramina with anterior directed force vectors (26.4 strain). With an anterior-caudal force vector, the measured values were usually lower. Discussion: The measured strains were on average about hundredfold lower than the Frost thresholds (2000 strain). It does not seem probable that the strains occurring upon maxillary protraction therapy suffice to stimulate any additional bone growth. Conclusion:The good clinical efficacy of maxillary protraction therapy is apparently based, for the most part, on dental effects, while its skeletal effects still remain doubtful.

The objectives of this review were to evaluate the currently available evidence regarding the effectiveness of surgical versus non-surgical acceleration methods and the side effects associated with these methods. Nine databases were searched: the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE ® , Scopus ® , PubMed ® , Web of Science™, Google™ Scholar, Trip, OpenGrey, and PQDT OPEN from pro-Quest ® . ClinicalTrials.gov and the International Clinical Trials Registry Platform Search Portal (ICTRP) were screened to explore ongoing studies and unpublished literature. Randomized controlled trials (RCTs), as well as controlled clinical trials (CCTs) of patients who received surgical interventions (invasive or minimally invasive techniques) in conjunction with traditional fixed appliances and who were compared to the non-surgical interventions, were included. The Cochrane tool for risk of bias (RoB.2) was used for evaluating RCTs, whereas the ROBINS-I tool was used for the CCTs. This systematic review included four RCTs and two CCTs (154 patients). The surgical and non-surgical interventions were found to have the same effect on orthodontic tooth movement (OTM) accelerating in four trials. In contrast, the surgical interventions were superior in the other two studies. High heterogeneity among the included studies prevented conducting the quantitative synthesis of the findings. The reported side effects related to the surgical and non-surgical interventions were similar. A "very low" to "low" evidence indicates that the effectiveness of surgical and non-surgical interventions in the acceleration of orthodontic tooth movement is similar, with no differences in the associated side effects. More high-quality clinical trials to compare the acceleration effectiveness between both modalities in different types of malocclusion is required.