Aligner hybrid orthodontic approach to treat severe transverse divergence in an adolescent girl: A case report.

OBJECTIVE: To resolve a complex Class II case with unilateral crossbite through an aesthetic approach, namely a hybrid orthodontic treatment combining aligners with miniscrews and auxiliaries. MATERIALS AND METHODS: A 14-year-old hypodivergent female patient with dental Class II and posterior crossbite presented for orthodontic treatment. The patient refused conventional fixed multibracket treatment and was therefore prescribed aligners used in association with miniscrews and sectional lingual appliances. Pre- and post-treatment records and 2-year follow-up records are presented. RESULTS: Treatment objectives, namely ideal occlusion and improved profile, were achieved in 12 months. Post-treatment panoramic radiography showed good root parallelism, and no sign of either crestal bone height reduction or apical root resorption. The patient was satisfied with the functional and aesthetic outcomes, which were stable at 2 years. CONCLUSION: This case report illustrates that a hybrid aligner approach may be used to treat posterior crossbite and class II malocclusion with reduced treatment times, optimal oral hygiene and excellent aesthetics.

Micro-computed tomography evaluation of general trends in aligner thickness and gap width after thermoforming procedures involving six commercial clear aligners: An in vitro study.

OBJECTIVE: To assess the effects of thermoforming on aligner thickness and gap width in six aligner systems with the same nominal thickness. METHODS: Six passive upper aligners of different brands were adapted to a single printed cast. Each sample was evaluated with high-resolution micro-computed tomography. To investigate aligner thickness and gap width, two-dimensional (2D) analysis was conducted assessing the effects of the following variables: tooth type (central incisor, canine, and first molar), 2D reference points, and aligner type. Data were analyzed and compared using analysis of variance and Tukey's post-hoc tests (p < 0.05). RESULTS: Tooth type, dental region, and aligner type affected both the gap width and aligner thickness. The aligner thickness remained moderately stable across the arch only in the F22. CONCLUSIONS: All thermoformed samples displayed smaller aligner thickness and gap width at anterior teeth and both gingival and coronal centers than at posterior teeth and occlusal surfaces.

MicroCT X-ray comparison of aligner gap and thickness of six brands of aligners: an in-vitro study.

BACKGROUND: To investigate and compare the gap (i.e. fit) and thickness of six aligner systems (Airnivol, ALL IN, Arc Angel, F22, Invisalign and Nuvola) using industrial computed tomography (CT). The null hypothesis was that there would be no detectable differences in either measurement between the aligners investigated. MATERIALS AND METHODS: Passive aligners of each brand were fitted to one single resin cast prototyped from an STL file from a single patient. The samples obtained were examined under high-resolution micro-CT, and the resulting tomographic microphotographs and volumetric data were compared. 3D analysis investigated the gap volume, the mean gap width and the maximum gap width of each sample. A total of 204 linear 2D measurements were made on 18 microtomographic images to investigate the aligner gap and thickness among different systems. Investigated regions were the central incisor, canine and first molar. The resulting measurements were analysed by ANOVA and compared using Tukey's post hoc analysis (P < 0.05). RESULTS: 3D analysis revealed that the F22 displayed lower gap volume and mean gap width, followed by Airnivol and Invisalign, whereas Airnivol the lowest maximum gap width. 2D analysis showed that F22 had the lowest mean gap and aligner thickness at all teeth investigated. Comparison of the 2D point values revealed statistically significant differences between brands in terms of both measurements (P < 0.05), with the exception of six points in the gap analysis and one in the thickness analysis. CONCLUSIONS: There are differences between the six aligner systems examined in terms of 2D and 3D measurements of aligner thickness and gap.

Comparative analysis of jaw morphology and temporomandibular disorders: A three-dimension imaging study.

Objective: To investigate the association between volumetric measurements of craniofacial morphology and temporomandibular disorders (TMDs). Methods: Computerized tomography (CT) scans of 20 individuals aged 18 to 40 with (TMD group) or without TMJ pain (control group) were gathered based on a case-control design. Three-dimensional reconstructions were performed to evaluate the gonial angle, condylar volume, and the distance between the posterior edge of the condyle and the sigmoid notch. Results: The gonial angle was significantly larger (8% difference) in the TMD group with respect to controls, whereas the condylar volume was significantly higher in the control group (15.2% difference). No significant difference was found in the linear distance. Conclusion: There is an association between the presence of TMJ pain and some features of craniofacial morphology. Individuals with TMJ pain have a lower condylar volume and a tendency towards hyperdivergent growth.

Preliminary biometric analysis of mesiodistal tooth dimensions in subjects with normal occlusion.

INTRODUCTION: The aims of this study were to confirm the efficacy of the Bolton index in a group of natural Class I white Italian patients with complete dentition, minimal crowding, and no previous orthodontic treatment, and to evaluate the mesiodistal tooth dimensions with multivariate cluster analysis. METHODS: Tooth measurements were obtained from a sample of 56 patients with normal occlusion, with a normal Bolton index (22 men, 34 women; mean age, 27.8 years), without previous orthodontic treatment or prosthetic or Class II restorations. Maxillary and mandibular measurements were analyzed separately in the sexes. Clustering was performed using the partitioning around medoid algorithm and principal component analysis-based transformed data. Statistical analysis was conducted. RESULTS: The multivariate analysis showed 3 distinct clusters of both maxillary and mandibular tooth measurements in the male and female subjects. Statistically significant differences were found between the sexes in terms of average tooth measurements, and there was significant proportionality between the maxillary and mandibular arch clusters. CONCLUSION: Although the Bolton index is useful for identifying dentodental discrepancies in most patients, cluster analysis enabled the mandibular and maxillary tooth dimensions of the male and female subjects to be divided into 3 general classes (clusters) and the precise location of the discrepancies to be pinpointed.

Temporomandibular Joint Disorders in Patients With Different Facial Morphology. A Systematic Review of the Literature.

PURPOSE: The present article aimed to review systematically the literature on the relation between facial skeletal structures and temporomandibular joint (TMJ) disorders. MATERIALS AND METHODS: A systematic search in the dental and medical literature was performed to identify all studies of humans assessing the relation between TMJ disorders and facial morphology. Articles were included based on study design, irrespective of TMJ disorder (eg, disc displacement, osteoarthrosis, or unspecified), skeletal features, diagnostic strategies (e.g., imaging techniques or clinical assessment), and population (eg, demographic features of participants) under investigation. The selected articles were assessed according to a format based on patients, problem, and population, intervention, comparison, and outcome and quality was evaluated based on the Newcastle-Ottawa Scale. RESULTS: Thirty-four articles were included in the review, 27 of which concerned adult samples and 7 concerned adolescent samples. Quality was generally moderate. The articles dealt with the relation between facial morphology and the following TMJ disorders, assessed clinically or by magnetic resonance (MR): disc displacement (n = 20), osteoarthritis or osteoarthrosis (n = 8), and temporomandibular disorder signs and symptoms (n = 6). The different approaches featuring the various investigations and the presence of some potential methodologic biases complicated a summary of the findings. Most studies reported that some features related to the vertical dimension of the face might help distinguish patients with potential TMJ disc displacement or MR-detected signs of osteoarthrosis from those without TMJ disorders. CONCLUSIONS: The quality of the available literature is not adequate to provide an evidence base on the topic. Despite the heterogeneity of design and findings of the reviewed articles, it seems reasonable to suggest that skeletal Class II profiles and hyperdivergent growth patterns are likely associated with an increased frequency of TMJ disc displacement and degenerative disorders.

Distribution of diagnoses in a population of patients with temporomandibular disorders.

OBJECTIVES: The objective of this study was to describe the frequency of TMD diagnoses in a patient population for comparison with the available literature. METHODS: Five hundred twenty consecutive patients seeking TMD treatment underwent a Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) assessment. The prevalence and age distribution of the different RDC/TMD axis I and II diagnoses were described. RESULTS: Muscle disorders, disk displacements, and other joint disorders were diagnosed respectively in 56.4%, 42.0%, and 57.5% of patients. Sixty percent of patients had depression symptoms, 76.6% had somatization, and 21.8% presented high levels of pain-related impairment. Disk displacements were more frequently diagnosed in the younger-aged, other joint disorders in the older-aged, and muscle disorders in the middle-aged subjects (ANOVA for mean age comparison, F = 3.355; P = .002). CONCLUSIONS: These distribution frequencies of TMD diagnoses provide insight into the epidemiology of this disease.