Influence of maxillary canine torque variations on the perception of smile esthetics among orthodontists and laypersons

Influence of orthodontic bracket prescription on smile attractiveness in patients with different sagittal skeletal patterns: A 3-dimensional cross-sectional study

INTRODUCTION

The objective of this study was to evaluate the influence of orthodontic bracket prescription on smile attractiveness.

METHODS

Three women were chosen according to their sagittal skeletal pattern: skeletal Class I, II, or III malocclusion. For each, 3 smiling pictures were taken in frontal, oblique, and lateral views. The maxillary arch was then scanned, and a 3-dimensional digital model was constructed on the OrthoAnalyzer software. The information of 3 orthodontic prescriptions, namely Roth, MBT, and Ricketts, was simulated after the virtual placement of orthodontic brackets on 10 maxillary teeth. The simulations were then superimposed on the smile photographs in the 3 views, creating a total of 27 images. Groups of orthodontists, dentists, and laypeople rated the attractiveness of each smile using the visual analog scale.

RESULTS

This study included 167 evaluators: 54 orthodontists, 54 dentists, and 59 laypersons. In terms of orthodontic prescription, MBT esthetic scores were 4% lower than Roth scores (P <0.001), and Ricketts scores were 13.6% lower than Roth scores (P <0.001). In terms of skeletal pattern, Class II and III scores were 15.0% and 16.4% lower than Class I scores, respectively (P <0.001). Regarding the smiling view, oblique view scores were 3.1% lower than frontal view scores (P = 0.031), whereas lateral view scores were 8.4% lower than frontal view scores (P <0.001). In contrast to gender and age, the specialty of the evaluators significantly affected the esthetic rating of the smiles.

CONCLUSIONS

The attractiveness of a smile is affected by the prescription of the brackets. The Roth prescription tends to obtain the most favorable esthetic scores, especially in sagittal smiling images. Profile smiles with excessively proclined incisors are considered unattractive. Different views of the same smile do not get similar esthetic scores because sagittal views are rated the most severely.

Three-dimensional evaluation of social smile asymmetry in patients with unilateral impacted maxillary canine: a 3D stereophotogrammetry study

OBJECTIVE

This study aimed to evaluate social smile asymmetry in patients with unilateral impacted maxillary canine on 3D stereophotogrammetric images.

MATERIAL AND METHODS

The 3D social smile images of participants with unilateral impacted maxillary canine (n:20) and without impaction as a control group (n:20) were included. The images were recorded with a hand-held 3D stereophotogrammetry device (Fuel3D® Scanify®) and Geomagic Essentials 2 reverse engineering software were used for analyses. After the orientation process of the 3D records, the tissues around the smile area were divided into five morphological regions: cheek, upper lip lateral and medial, and lower lip lateral and medial. The deviation margins in the negative and positive directions for the 95% mesh rate and the total percentages of meshes between - 0.5- and + 0.5-mm deviations were calculated. ICC, paired samples t test, independent samples t test, and the Mann-Whitney U test were used for statistical analyses.

RESULTS

In individuals with impacted canine, the amount of maximum positive deviation in the upper lip medial was 5.64 mm ± 1.46 and maximum negative deviation was - 4.6 mm ± 1.17. In the control group, mean of deviation limits for all parameters was less than 1.19 mm ± 2.62, while in individuals with unilateral impacted maxillary canine, the maximum value was 8.34 mm ± 2.23. The mesh percentage between - 0.5 and 0.5-mm deviations was over 95% in all morphological areas in the control group, while in the impacted canine group, the number of meshes within the specified deviation limits was less than 95%.

CONCLUSION

Individuals with unilateral impacted maxillary canine exhibit greater asymmetry in social smile compared to the control group, with the asymmetry being most prominent near the corners of the mouth and cheeks.

CLINICAL RELEVANCE

Amount of asymmetry was higher in impaction group compared to the control group in social smile. The quantification of a possible smile asymmetry due to the impacted canine is crucial for the diagnosis and treatment planning of orthodontic and/or orthognathic cases for ideal aesthetic results. Hence, smile asymmetry should not be overlooked and should be considered in diagnosis and treatment planning.

Role of Dentofacial Harmony among Young and Old Adult Females in Smile Perception of Dental Specialists and Laypeople: A Cross-Sectional Study

Introduction

The purpose of this study was to determine whether balance and harmony of the face, when seen as a whole, alter the smile perception as compared to a lone standing smile in female subjects of two age groups and to identify parameters of dental composition and dentofacial harmony associated with the smile perception of dental specialists (DS) and laypeople (LP).

Settings and Design

A cross-sectional study.

Materials and Methods

Twenty-nine DS and 29 LP scored the smile attractiveness of 84 full-face images (FFIs) and corresponding smile images (SIs) of young adults (YA: 20-29 years) and old adults (OA: 50-59 years), using the Visual Analogue Scale. Smile analysis software (Planmeca Romexis®Smile-Design) was used to measure 10 parameters of dental composition and dentofacial harmony in FFI.

Statistical Analysis Used

Independent t-test and Pearson's correlation coefficient (r) were used to analyze the data.

Results

A significant difference was not seen between the smile attractiveness scores of FFI and SI in both raters and age groups. Significant differences were observed between DS and LP in the YA group. The OA group was rated significantly higher than the YA group. The correlation between smile attractiveness scores and each of the nine dentofacial parameters was not significant (P < 0.05).

Conclusions

Framing of images did not significantly alter smile perception. FFI received higher scores than SI, and raters were more critical of the YA group. Professional training of raters and an interplay of smile and facial attractiveness of the female subjects contributed to the smile perception of raters. No parameters of dental composition or dentofacial harmony significantly associated with smile attractiveness were identified.

The effect of torque and vertical position of maxillary canine on smile esthetics

INTRODUCTION

Regarding the key role of the maxillary canine in dynamic occlusion and smile esthetics, this study investigated the relation between smile esthetics and maxillary canine torque and vertical position from the viewpoint of orthodontists, general dentists, and laypersons.

METHODS

In this descriptive cross-sectional study, the close-up smile images have been changed using Adobe Photoshop (Adobe Systems, San Jose, Calif). Then, groups of 21 orthodontists, 20 general dentists, and 33 laypersons evaluated the smile attractiveness of the images using a digital version of a visual analog scale. Statistical analysis was performed using SPSS software (version 25; IBM, Armonk, Calif) and Shapiro-Wilk, analysis of variance, and Tukey post-hoc statistical tests. The significance level was set at 0.05.

RESULTS

There was no significant difference in the mean score between the 3 groups of observers regarding the changes in the canine vertical position in none of the variations (P >0.05). Regarding variations in torque, there was a significant difference between the 3 groups of observers in the bilateral 5° torque change. (P = 0.020).

CONCLUSIONS

Unilateral changes in the vertical position had lower scores, which shows that symmetry is very important in smile esthetics. In addition, laypersons did not find torque changes ranging between -15° to 15° a significant factor in smile esthetics. Overall, some adherence to these values will be acceptable in dental treatments.

Investigation of the esthetic perception of different canine parameters

OBJECTIVES

The aim of this study is to analyze the esthetic perception of selected canine features, namely crown length, shade, inclination, and angle of incisal edge tip.

MATERIALS AND METHODS

The anterior maxillary teeth of a Central European woman were photographed and digitally modified in order to investigate esthetic perceptions of the above four categories. Three groups of examiners with different levels of experience in the field of dentistry (laypersons/inexperienced dental students, advanced dental students, dentists) evaluated the photographs twice with the help of visual analogue scales.

RESULTS

The best-evaluated canines have approximately the same length as the central incisor, have the same shade as the other anterior teeth, are best embedded in a lighter overall tooth shade, are neutral to slightly palatal inclined, and have a right angled to rounded incisal edge (≥ 90°). The canines evaluated as least esthetic, however, are longer than the central incisors, darker, inclined labially, and have a tapered incisal edge. No significant differences could be found between the evaluations of the groups with regard to the four feature categories.

CONCLUSIONS

Laypersons, advanced dental students, and dentists generally evaluate according to the same esthetic standards. Gender does not have a significant influence on evaluation. Clear definitions of esthetically favored shades, incisal edge shapes, inclination, and lengths of the canines can be given.

CLINICAL RELEVANCE

Since the esthetics of the smile line play a critical role for patients, dentists, dental technicians, and their supplying industry, knowledge of the esthetically preferred morphology of canines is essential.

CLINICAL SIGNIFICANCE

The aim of this study is to give clear definitions of esthetically favored shades, incisal edge shapes, and lengths of the canines, as the esthetics of the smile line play a critical role for patients, dentists, dental technicians, and their supplying industry (e.g., denture tooth manufacturers). Precise knowledge of esthetic preferences is important in clinical practice for both dentists and dental technicians, for example, in order to adequately advise patients regarding esthetic corrections. Also, in the case of missing teeth, this knowledge is essential for optimal and satisfactory restorations. Thus, this study can contribute to the satisfaction of general practitioners and patients.

Comparation of three methods for measuring the Edge Bevel Radius of rectangular orthodontic wires: An in-vitro study

OBJECTIVE

To establish a simplified method for measuring the edge bevel radius of 0.019×0.025-in steel rectangular orthodontic wires, achievable in the clinical environment, and to compare it with the photographic method.

MATERIALS AND METHODS

Aided by the AutoCAD™ 2016 software, the theoretical mathematical relationship was determined between the edge rounding radius and cross-sectional dimensions (height, width, diagonals), through rectangle drawings that represent cross-sections. Two hundred segments (n=20) were obtained from the posterior portions of 100 archwires from 10 brands (Dentaurum™; American-Orthodontics™; GAC™; 3M-Unitek™; Abzil™; Morelli™; Orthometric™; Aditek™; A-Company™; Orthomundi™). The cross-sectional measures of each segment were obtained with a micrometer and a caliper, and the edge bevel radii of these segments were calculated with the use of a mathematical formula. For the "gold standard", the segments were included longitudinally in a phenolic resin cylinder, cross-sectioned, polished, and photographed in scanning electron microscope (SEM). The images were amplified 770× and the radii were measured with an acetate template. The micrometer and caliper measuring methods were subjected to Bland-Altman analysis and compared with the gold standard (SEM), considering ±10μm as the maximum acceptable difference between methods.

RESULTS

In the micrometre measurement, 95% of the differences from the standard were within the limits of agreement (-7.21 and 5.56μm). For the caliper method, 95% of the differences were between -5.46 and 19.83μm, which exceeded the fixed limit ±10μm.

CONCLUSION

The calculation method with micrometre measurements is equivalent to the photographic method, but there is no such equivalence for the caliper measurements.