Geometric Morphometric Analysis of Mandibular Symphysis Growth between 12 and 15 Years of Age in Class II Malocclusion Subjects.

The aim of the present paper was to evaluate the morphology changes of the mandibular symphysis (MS) in a longitudinal retrospective cohort of class II untreated subjects. The study sample included 120 subjects followed during normal growth and examined at the age of 12 (T0) and 15 (T1) years. MS was traced using two landmarks and ten sliding semi-landmarks. The acquired morphological data were processed via Procrustes superimposition that allowed to study variation and covariation in MS'form according to specific variables such as age, gender, and skeletal pattern. The first two principal components (PCs) described more than 90 % of the total morphological variation. Both types of form changes of the symphysis could be associated with the different skeletal vertical growth patterns. Age and sex did not interfere with the form of chin symphysis. Moreover, there was no significant covariation between initial MS morphology and form modifications. Clinicians should not expect to be faced with spontaneous changes of the form of the symphysis during the orthodontic treatment of adolescents.

Palatal changes after treatment of functional posterior cross-bite using elastodontic appliances: a 3D imaging study using deviation analysis and surface-to-surface matching technique.

BACKGROUND: The present study aimed to evaluate the changes in palate dimension and morphology after treatment of functional posterior crossbite (FPXB) with elastodontic devices (EAs). METHODS: The treatment group (TG) consisted of 25 subjects (mean age 7.3 ± 0.9 years) who received treatment with EA for one year. The control group (CG) comprised 14 untreated subjects (mean age 6.8 ± 0.7 years). INCLUSION CRITERIA: intra-oral scan registered before (T0) and after treatment (T1), FPXB with a mandibular shift towards the crossbite site of ≥ 2 mm, class I molar relationship. EXCLUSION CRITERIA: missing teeth, anterior crossbite, temporomandibular disorders, previous orthodontic treatment, carious lesions, mobility of deciduous posterior teeth, craniofacial deformities. Digital models were analyzed to assess the inter-canine (ICW) and inter-molar widths (IMW) and the corresponding emi-lateral measurements (eICW and eIMW) using the median palatine plane as reference. According to a specific 3D imaging technology, the morphology and symmetry of the palate was investigated by analysing the 3D deviation between the two specular models of the palate. RESULTS: At T0, both groups showed a significantly narrower dimension of eICW and eIMW at the crossbite side compared to the non-crossbite side (p < 0.05). Also, the 3D deviation analysis demonstrates a limited matching percentage of the original/mirrored models in both TG (81.12%) and CG (79.36%), confirming the asymmetry of the palate. The area of mis-matching was located at the alveolar bone level. At T1, subjects in the TG showed a significant increment of ICW and IMW (p < 0.05), a reduction of the differences of eICW and eIMW between both sides (p < 0.05) and an increment of the percentage matching (TG = 92.32%) (p < 0.05), suggesting a significant recovery of the palatal asymmetry. No significant changes were found between T0 and T1 in the CG (p > 0.05). CONCLUSIONS: EAs could be successfully used to correct FPXB in mixed dentition and could restore the harmonious development of the palate in children.

MicroRNA Modulation during Orthodontic Tooth Movement: A Promising Strategy for Novel Diagnostic and Personalized Therapeutic Interventions.

The Orthodontic Tooth Movement (OTM) is allowed through a mediated cell/tissue mechanism performed by applying a force or a pair of forces on the dental elements, and the tooth movement is a fundamental requirement during any orthodontic treatment. In this regard, it has been widely shown that each orthodontic treatment has a minimum duration required concerning numerous factors (age, patient compliance, type of technique used, etc.). In this regard, the aim of the following revision of the literature is to give readers a global vision of principal microRNAs (miRNAs) that are most frequently associated with OTM and their possible roles. Previously published studies of the last 15 years have been considered in the PubMed search using "OTM" and "miRNA" keywords for the present review article. In vitro and in vivo studies and clinical trials were mainly explored. Correlation between OTM and modulation of several miRNAs acting through post-transcriptional regulation on target genes was observed in the majority of previous studied. The expression analysis of miRNAs in biological samples, such as gingival crevicular fluid (GCF), can be considered a useful tool for novel diagnostic and/or prognostic approaches and for new personalized orthodontic treatments able to achieve a better clinical response rate. Although only a few studies have been published, the data obtained until now encourage further investigation of the role of miRNA modulation during orthodontic treatment. The aim of this study is to update the insights into the role and impact of principal micro-RNAs (miRNAs) that are most frequently associated during OTM.

Facial Scanning Accuracy with Stereophotogrammetry and Smartphone Technology in Children: A Systematic Review.

The aim of the study was to systematically review and compare the accuracy of smartphone scanners versus stereophotogrammetry technology for facial digitization in children. A systematic literature search strategy of articles published from 1 January 2010 to 30 August 2022 was adopted through a combination of Mesh terms and free text words pooled through boolean operators on the following databases: PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and OpenGrey. Twenty-three articles met the inclusion criteria. Stationary stereophotogrammetry devices showed a mean accuracy that ranged from 0.087 to 0.860 mm, portable stereophotogrammetry scanners from 0.150 to 0.849 mm, and smartphones from 0.460 to 1.400 mm. Regarding the risk of bias assessment, fourteen papers showed an overall low risk, three articles had unclear risk and four articles had high risk. Although smartphones showed less performance on deep and irregular surfaces, all the analyzed devices were sufficiently accurate for clinical application. Internal depth-sensing cameras or external infrared structured-light depth-sensing cameras plugged into smartphones/tablets increased the accuracy. These devices are portable and inexpensive but require greater operator experience and patient compliance for the incremented time of acquisition. Stationary stereophotogrammetry is the gold standard for greater accuracy and shorter acquisition time, avoiding motion artifacts.