Evaluation of the perception of smile esthetics, in frontal view, with mandibular laterognatism, through the eye-tracking technique.

OBJECTIVES: To evaluate the perception of esthetics and the attractiveness of the smile, in frontal view, with mandibular asymmetry, through the eye-tracking. MATERIALS AND METHODS: OGAMA software and The Eye Tribe Tracker hardware were used to obtain eye tracking in certain areas of interest on the face. To simulate asymmetry, Photoshop® image editing software was used to create a vertical reference line to the midline of the face and make it symmetrical with control of the angulation relative to another horizontal reference line passing through the vertices. Then, the lower third of the face added asymmetries or deviations, starting from zero, with increments of 2 by 2 degrees up to 6 degrees. The study included 60 laypeople, 30 males and 30 females, without any knowledge about the study, showing good vision, and not having used drugs with the possibility of influencing cognitive or motor skills. RESULTS: From the heat map in cases of mandibular asymmetry, it is possible to visualize that for both sexes the evaluators evaluated with a certain degree of similarity mainly when the deviations presented with 6 degrees. The trajectory of the male and female gaze in cases with asymmetry shows that in cases with a magnitude of 6 degrees, the raters traced mainly in the region of the mouth with little transition in the eye region and mainly in the areas of interest considered as "other." In the images presented with a magnitude of up to 4 degrees, they were traced in the general image. CONCLUSIONS: The perception of laypeople from mandibular asymmetry to the right in females presented a higher perception when compared to males with mandible asymmetry to the left.

Miniscrew Composition, Transmucosal Profile, and Cortical Bone Thickness: A Three-dimensional Finite-element Analysis of Stress Fields.

AIM: The aim of this study was to use the finite-element method (FEM) to analyze the stress fields generated in miniscrews (MSs) and surrounding bone on applying a force perpendicular to the MS according to variations in the cortical bone thickness and changes in the transmucosal profile length and MS composition. MATERIALS AND METHODS: Miniscrews with stainless steel (SS) and titanium alloy mechanical properties with a 1 to 2 mm transmucosal profile inserted in bone blocks with cortical bone of varying thickness (1 and 2 mm) were three-dimensionally modeled using computer-aided design (CAD) and examined using FEM. A 3.5 N force perpendicular to the long axis of the MS was applied in the four mechanical tests: EM1: SS MS and a 1 mm transmucosal profile; EM2: titanium MS and a 1 mm transmucosal profile; EM3: SS MS and a 2 mm transmucosal profile; and EM4: titanium MS and a 2 mm transmucosal profile. RESULTS: The stress distributions in all mechanical tests were highest at the MS, especially at the MS-cortical bone interface. A greater stress concentration occurred in cortical bone measuring 1 mm thick than in the cortical bone measuring 2 mm thick. The MSs with a 2 mm transmucosal profile showed higher stress than those with a 1 mm transmucosal profile. CONCLUSION: The titanium alloy MSs showed higher stress fields and deflection voltages than the SS MSs at the same cortical bone thickness and with the same transmucosal profile. CLINICAL SIGNIFICANCE: From a mechanical perspective, this study showed the stress field generated in MSs with SS and titanium alloy (Ti) mechanical properties and surrounding bone. The stress distribution was concentrated at the MS, mainly at the interface with the cortical bone, and the difference between the stress values for the Ti and SS MSs was very small. Under this condition, the two types of MSs are suitable for orthodontic applications because their yield limits are much higher.

Clinical Outcome of an Impacted Maxillary Canine: From Exposition to Occlusion.

AIM: The aim is to report a case of impacted maxillary right canine successfully positioned into the occlusion line. BACKGROUND: Although the treatment of choice for an impacted canine is a combined surgical-orthodontic approach, there are differences in technique. The preorthodontic uncovering and autonomous eruption technique is a safe and predictable option for the treatment of palatally impacted maxillary canines in adolescents and adults as is the orthodontic creation of a space before minimal surgical exposure, the bonding of a small attachment (an eyelet), full-flap closure, and immediate traction. Although the mechanical management of impacted teeth is a routine task for most orthodontists, certain types of impaction can be frustrating. CASE DESCRIPTION: An 18-year-old adult patient presented for clinical examination with a mobile maxillary right deciduous canine, the absence of a maxillary right permanent canine, Angle Class I malocclusion, an overjet of 2.0 mm, an overbite of 3.0 mm, and rotated canine and left maxillary central and lateral incisors. Cephalometric measurements revealed a skeletal Class I relationship as well as upright maxillary incisors (1. NA = 18°) and mandibular incisors (1. NB = 16°, IMPA = 80°). The facial profile was concave. Clinically, a constricted maxillary arch was observed, and the patient had a nail-biting habit. CONCLUSION: The canine was aligned, leveled and positioned in the occlusion line. The esthetic, functional and periodontal results remained stable in the retention phase. CLINICAL SIGNIFICANCE: Various treatment strategies are available to treat impacted maxillary canines. The surgical, periodontal, and orthodontic considerations in the management of impacted canines must be clearly explained to the patient.