Forces and moments generated by aligner‐type appliances for orthodontic tooth movement: A systematic review and meta‐analysis

The aim of this review was to systematically appraise the evidence on aligner mechanics and forces and moments generated across difference types of aligners. In vitro- laboratory studies for model simulated tooth movement with aligners. Database searches within Medline via Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), LILACS via BIREME Virtual Health Library. Unpublished literature was also searched in Open Grey, ClinicalTrials.gov (www.clinicaltrials.gov), the National Research Register (www.controlled-trials.com) and Center for Open Science (Open Science Framework), using the terms "aligner" AND "orthodontic". Risk of bias assessment was based on the Cochrane Risk of Bias tool. Random effects meta-analyses were conducted. A total of 447 studies were identified through electronic search and after careful consideration of pre- defined eligibility criteria, 13 deemed eligible for inclusion, while 2 were included in the quantitative synthesis. When palatal tipping of the upper central incisor through PET-G aligners was considered, aligner thickness of 0.5, 0.625 or 0.75 mm was not associated with a significantly different moment to force (M/F) ratio, given a common gingival edge width of 3-4 mm. Aligner thickness does not appear to possess a significant role in forces and moments generated by clear aligners under specific settings, while the most commonly examined tooth movements are tipping and rotation. The findings of this review may be applicable to certain conditions in laboratory settings. Keywords: aligner; force; meta-analysis; moment; systematic review; tooth movement

Familial aggregation of maxillary lateral incisor agenesis

In spite of recent developments, data regarding the genes responsible for the less severe forms of hypodontia are still scarce and controversial. This study addressed the hypothesis that agenesis of maxillary lateral incisors (MLIA) is a distinct type of hypodontia, by evaluating its familial aggregation and the occurrence of other types of ageneses or microdontia in probands' relatives. Sixty-two probands with MLIA were identified, and information was collected on 142 first-degree relatives. Relative risk (RR) was calculated and compared by re-assessment of data previously published for the Swedish, Utah, and Israeli populations, for the same trait. A RR of 15 was obtained in the Portuguese, 16 in the Swedish, 12 in Utah, and 5 in the Israeli population. Our results support a significant familial aggregation of MLIA, show that MLIA almost never segregates with other forms of agenesis, and suggest that microdontia of maxillary lateral incisors is part of the same phenotype.The individuals who took part in this study are acknowledged. Carolina Lemos was the recipient of a PhD scholarship (FCT - SFRH/BD/17761/2004) and Teresa Pinho of a PhD scholarship from Instituto Superior de Ciencias da Saude Norte/CESPU. The other authors received no funding from any institution, department, or sponsor, other than salaries from the institutions with which they are affiliated

3D Airway changes using cone beam computed tomography in patients following mandibular advancement surgery with and without constriction

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149306/1/ocr12292.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149306/2/ocr12292_am.pd

Superimposition of 3D cone-beam CT models of orthognathic surgery patients

To evaluate the registration of 3D models from cone-beam CT (CBCT) images taken before and after orthognathic surgery for the assessment of mandibular anatomy and position

Cephalometric norms for the Saudi children living in the western region of Saudi Arabia: a research report

BACKGROUND: Previous studies have established specific cephalometric norms for children with different ethnic backgrounds, showing different facial features for each group. Up till now, there is a paucity of information about the cephalometric features of Saudi children living in the western region of Saudi Arabia, who have distinct social and climatic characteristics. The aim of the present study was to establish cephalometric norms for children living in the western region of Saudi Arabia. METHODS: A total of 62 lateral cephalometric radiographs of Saudis (33 females and 29 males; aged 9–12 years) having good facial proportions and Class I dental occlusion, were traced and analyzed. Using the t-test, the mean value, standard deviation and the range of 20 angular and linear variables were calculated and compared to norms of adult Saudis living in the Western region of Saudi Arabia using the t-test. Male and female groups were also compared using the t- test. RESULTS: Saudi children tend to have a significantly shorter and lower face height, a larger angle of convexity, and more proclined and protruded incisors when compared with adult Saudis (P < 0.05). There were no statistically significant differences between male and female groups. CONCLUSION: Saudi children have distinct cephalometric features, which should be used as a reference in the orthodontic treatment of young Saudi patients

3D Airway changes using CBCT in patients following mandibular setback surgery ± maxillary advancement

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149310/1/ocr12291_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149310/2/ocr12291.pd

Three- dimensional assessment of craniofacial asymmetry in children with transverse maxillary deficiency after rapid maxillary expansion: A prospective study

ObjectiveThe aim of this study was to evaluate craniofacial asymmetry in children with transverse maxillary deficiency, with or without functional unilateral posterior crossbite (UPC), before and after rapid maxillary expansion (RME).Setting and sample populationA sample of 51 children with cone beam computed tomography scans obtained before RME (T1) and a year after RME (T2).Material and methodsThis prospective study consisted of 2 groups: 25 children with functional UPC (6.77 ± 1.5 years) and 26 children without UPC (7.41 ± 1.31 years). Linear and angular measurements were obtained from zygomatic, maxilla, glenoid fossa and mandible, using original and mirrored 3D overlapped models. All right and left side comparisons in both groups and intergroups asymmetries were compared using MANOVA and t test for independent samples, respectively, statistically significant at P < .05.ResultsThe UPC group showed no side differences, but mandibular horizontal rotation at T1, and this asymmetry was improved in T2. The non- UPC group showed at baseline significant lateral asymmetry in orbitale, position of palatine foramen, respectively, in average 2.95 mm and 1.16 mm, and 0.49 mm of average asymmetry in condylar height. The glenoid fossa was symmetric in both groups at T1 and T2.ConclusionsChildren with transverse maxillary deficiency showed slight morphological asymmetry, located in the mandible position in cases of UPC, and in the orbital and maxillary regions in cases without UPC. One year after RME, patients improved their craniofacial asymmetry, with significant changes in the mandible and correction of the mandibular rotation in patients who presented UPC.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156195/2/ocr12370_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156195/1/ocr12370.pd