Laypeople's perceptions of frontal smile esthetics: A systematic review.

INTRODUCTION: The emphasis on dental esthetics has increased in recent years. There are, however, differences in esthetic perceptions among professional and lay groups. The aim of this comprehensive review was to update previous reviews and answer the following research question: Can lay thresholds for acceptance of smile esthetic anomalies be defined? METHODS: A systematic search in the medical literature (PubMed, PMC, NLM, Embase, Cochrane Central Register of Controlled Clinical trials, Web of Knowledge, Scopus, Google Scholar, and LILACs) was performed to identify all peer-reviewed articles reporting data regarding evaluations of laypeople's perceptions of dental esthetic factors. RESULTS: Of the 6032 analyzed articles, 66 studies were selected for the final review process. Among the selected articles investigated perceptions of diastema, 15 analyzed modifications in tooth size and shape, 8 considered incisor positions, 15 evaluated midline discrepancies, 16 investigated buccal corridors, 26 analyzed gingival display and design, 3 considered lip height, and 20 investigated miscellaneous factors. Threshold values were identified for the following features: diastema (0-2 mm), tooth size and shape of incisor position, midline discrepancy (0-3 mm), buccal corridors (5-16 mm), gingival exposure (1.5-4 mm), occlusal canting (0°-4°), and overbite (2-5 mm). Furthermore, few other smile characteristics were found to be significantly associated with perception of smile aesthetics, even though any threshold could be detected. CONCLUSIONS: On the basis of the obtained results, threshold values for the main features of smile and dental esthetics could be identified. Limitations of the present study were the heterogeneity of data which made it impossible to perform a meta-analysis, and the lack of information about sample selection and selective outcome reporting.

Efficiency in the correction of Class II division 1 malocclusions with prominent upper incisors and increased overjet: a comparison between two methods.

BACKGROUND: The aim of the present study was to evaluate the efficiency and effectiveness of high-pull traction on a Stephenson plate as well as cervical headgear treatments in Class II Division 1 growing subjects with prominent upper teeth and an increased overjet. METHODS: A prospective study was undertaken, involving participants who underwent maxillary correction of Class II malocclusions. Twenty-three patients (Stephenson plate group, SPG, mean age 10.4±0.9 years) were treated and compared with 24 subjects treated with headgear (HGG, mean age 9.6±1.2 years). Lateral cephalograms were analysed using Jarabak and Pancherz analysis. Shapiro-Wilk's and Student's t tests were applied. RESULTS: The SPG showed significant decreases in the overjet (-4.1 versus -0.8 mm) and molar relationship (-6.1 versus -1.5 mm). A significant upper-incisor correction was found in SPG (1/SpP -10.3° versus + 2.2°). SNA (-1.4 versus 0.3°) and WITS (-1 versus 0.3 mm) were reduced in SPG, showing a partial maxillary restraint. In SPG, the overjet correction (4.1 mm) was mainly due to the dental component (65.9%) and occurred almost completely in the maxilla (92.7%); the molar relationships improvement of 6.1 mm was mainly dental (77%); in HGG, the reduction of the overjet was limited (-0.8 mm), and the skeletal maxillary contribution was negligible. CONCLUSIONS: The high-pull traction on the Stephenson plate was more efficient and effective than HG in the treatment of Class II dentoskeletal malocclusions with prominent upper teeth and a severe overjet; the overjet reduction was obtained at approximately 6 months, contributing to the substantial Class II correction.

Orthodontic treatment with preadjusted appliances and low-friction ligatures: experimental evidence and clinical observations.

AIM: To describe the features of low-friction ligatures during the leveling and aligning phase of fixed appliance therapy with preadjusted brackets. METHODS: Experimental in vitro and in vivo studies were carried out to test the performance of the low-friction system with regard to leveling and aligning of the dental arches, as well as to increasing the transverse dimension of the maxillary arch. RESULTS: The outcomes of experimental testing showed that the combination of the low-friction ligatures with the superelastic nickel-titanium wires produced a significantly smaller amount of binding at the bracket/archwire/ligature unit when compared to conventional elastomeric ligatures. CONCLUSION: The biomechanical consequences of the use of low-friction ligatures were shorter duration of orthodontic treatment during the leveling and aligning phase, concurrent dentoalveolar expansion of the dental arch, and the possibility of using biologically adequate orthodontic forces.

Children's perceptions of smile esthetics and their influence on social judgment.

OBJECTIVE: To define a threshold of acceptance of smile esthetics for children and adolescents. MATERIALS AND METHODS: A systematic search in the medical literature (PubMed, PubMed Central, National Library of Medicine's Medline, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Knowledge, Scopus, Google Scholar, and LILACs) was performed to identify all peer-reviewed papers reporting data regarding the evaluation of children's and adolescents' perceptions of dental esthetic factors. The search was conducted using a research strategy based on keywords such as "children," "adolescents," "smile aesthetics perception," "smile aesthetics evaluation." Studies analyzing smile esthetics involving at least 10 observers younger than 18 years of age were selected. RESULTS: Among the 1667 analyzed articles, five studies were selected for the final review process. No study included in the review analyzed perception of smile anomalies in a quantitative or qualitative way, thus no threshold was identified for smile features. Among the analyzed samples, unaltered smiles were always significantly associated with better evaluation scores when compared with altered smiles. CONCLUSIONS: Smile esthetics influence social perception during childhood and adolescence. However, thresholds of smile esthetic acceptance in children and adolescents are still not available.

Dentoskeletal effects induced by rapid molar distalization with the first class appliance.

The purpose of this study was to evaluate the treatment effects of the first class appliance (FCA; Leone, Firenze, Italy), a new intraoral device for unilateral or bilateral rapid molar distalizaton. A retrospective study was conducted to compare the predistalization and postdistalization cephalograms of 17 patients (10 male, 7 female) with Class II malocclusions treated with the FCA. Mean age at the start of treatment was 13 years 4 months. The FCA produced rapid molar distalization, and the bilateral Class II molar relationship was corrected in 2.4 months, on average. Maxillary molar distalization contributed to 70% of the space created anterior to the first molars; 30% of the space was due to reciprocal anchorage loss of the maxillary second premolars. The maxillary first molars showed a significant distalization of 4.0 mm, associated with a significant distal axial incline of 4.6 degrees and a significant extrusion of 1.2 mm. As for anchorage loss, the second premolars exhibited a significant mesial movement of 1.7 mm, associated with a significant mesial axial incline of 2.2 degrees and a nonsignificant extrusion of 1.0 mm. In the anterior region, a significant mesial movement of the maxillary incisor of 1.3 mm was associated with a significant incisor proclination (2.6 degrees ) and a significant increase in overjet (1.2 mm). No significant changes in either sagittal or vertical skeletal relationships were observed. The results suggest that the FCA is an efficient and reliable device for distalizing the maxillary permanent first molars.