Is the Nasolabial Region Symmetric in Individuals With Cleft Lip and Palate?

OBJECTIVE: To assess the nasolabial symmetry in smile and resting position in individuals with nonsyndromic unilateral cleft lip and palate (UCLP) and compare with Class I individuals without cleft lip and palate (CLP). MATERIALS AND METHODS: Frontal photographs of 40 individuals with UCLP (mean age 14.30 ± 0.25 years; 20 female, 20 male) and 40 skeletal Class I individuals without CLP (mean age 14.60 ± 0.34 years; 20 female and 20 male) were examined. Bland-Altman Levels of Agreements, Mann-Whitney U test, independent sample t-test were conducted, and intraclass correlation coefficients (ICCs) were calculated for statistical analysis. RESULTS: Differences in the transverse lip distance (d-d') and vertical lip height at crista philtri (e-e') were lesser in the UCLP group at smile (P = .001; P = .005, respectively). When comparing the differences in these measurements at rest between control and UCLP groups, vertical lip height was longer at crista philtri (e-e') (P = .014), crista philtri was more laterally located (f-f') (P = .002), and the transverse lip distance was greater (d-d') (P = .004) in the UCLP group. Distance of the crista philtri to the midline of the face (f-f') (P = .007) were higher in the UCLP group during smiling compared to control group. CONCLUSIONS: Nasolabial region asymmetry in smiling and rest position in individuals with UCLP was significantly different from the control group. However, the asymmetry in the nasolabial region, which is more evident in the resting position in individuals with UCLP, decreases during smiling.

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.

Does YouTube provide adequate information about orthodontic pain?

OBJECTIVES: To evaluate the content and quality of information about orthodontic pain on YouTube. MATERIALS AND METHODS: YouTube was searched using the keywords "orthodontic pain" and "brace pain." A total of 65 videos were chosen for the final analysis. Videos were classified into high- and low-content groups using an eight-point scoring system and reviewed according to selected orthodontic pain-related topics. Video quality was rated by the Video Information and Quality Index (VIQI) and Global Quality Scale (GQS). Statistical data analysis was performed using SPSS 28.0 software, Mann-Whitney U-tests, χ2 tests, and Spearman correlation coefficients. RESULTS: Most YouTube videos related to orthodontic pain were low content (86.2%), and a few were high content (13.8%). Pharmacological pain relief was the most prevalent topic (50.8%), followed by duration of pain (32.3%) and influence of pain on patient quality of life (29.2%). The least-mentioned topic was possible location of pain (7.7%). Most of the videos were uploaded by laypeople (64.6%). Videos uploaded by dental professionals had significantly higher means of GQS scores (P = .035), flow of information (P < .001), information quality (P = .008), and total VIQI (P < .001). Compared with low-content, high-content videos had a higher mean of flow of information (P = .037). There was a weak correlation between total content and GQS scores and a strong correlation between GQS and VIQI scores (r = 0.740; P < .01). CONCLUSIONS: Overall, YouTube was found to be an inadequate source of information on orthodontic pain.

YouTube™ as an information source for regenerative endodontic treatment procedures: Quality and content analysis.

BACKGROUND: Regenerative endodontic procedures (REPs) are one of the most important developments in dental practice, and in the era of Covid 19 pandemic, audio-visual contents of YouTube™ could be an information source for dental students, practitioners and patients. The aim of this study was to evaluate the quality, content and the demographics of YouTube™ videos about REPs. METHODS: A search on YouTube™ was performed for REPs using "endodontic regeneration", "pulp regeneration", "regenerative endodontics", "regenerative endodontic procedures", "revascularization" and "revitalization" keywords. Totally 531 videos were found and 60 videos met the inclusion criteria. Following the assessment of the demographic features of the videos and the viewing rate of the videos were calculated. The content of the videos was evaluated based on the selected headings. The quality of the videos was assessed using the video information, quality index (VIQI), Global Quality Score (GQS) and DISCERN. The statistical analysis was performed using Spearman Correlation and linear regression analysis. RESULTS: Majority of the videos about REPs were created by dental professionals (91.7%). The most commonly covered topic was "clinical application" (76.7%). Total content score showed a positive correlation with total VIQI (r = 0.795; p < 0.001) and GQS (r = 0.952; p < 0.001). There were significant relationships between total content score, duration, GQS, total VIQI score and DISCERN. CONCLUSION: The findings revealed that YouTube™ videos about REPs provide predominantly clinical information about patient chairside practice of REPs and they could be considered as a supplementary information source for dental students and practitioners.

Is YouTube an adequate patient resource about orthodontic retention? A cross-sectional analysis of content and quality.

INTRODUCTION: The study aimed to evaluate the content and quality of information offered by YouTube for patients seeking information related to orthodontic retainers. METHODS: YouTube was searched using the keyword "orthodontic retainers" from Google Trends. From the first 120 results, 97 videos were selected to be analyzed. Videos were rated for quality by video information and quality index (VIQI) and the global quality scale (GQS). Videos were classified as low- and high-content groups using a 10-point score considering several retainer-related topics. Mann-Whitney U tests, chi-square tests, and Pearson correlation coefficients were used for statistical evaluations. RESULTS: Most YouTube videos were uploaded by dentists/specialists (62.9%). We classified 12 videos as high content and 85 as low content. Instructions on the use of the orthodontic retainer was the most commonly covered topic (42.3%), followed by the effect on oral hygiene (38.1%), definition (37.1%), procedure of preparing orthodontic retainers (33.0%), and procedure of positioning (30.9%). A lower percentage of videos (6.2%) mentioned soft tissue irritation. The high-content video group had a significantly higher median value of GQS score and VIQI (P <0.001). The correlation between GQS and VIQI was strong (r = 0.698; P <0.01). CONCLUSIONS: The content of YouTube videos for orthodontic retainers could not be considered as an adequate source of information for patients on orthodontic retainers. Most videos included instructions on the use of orthodontic retainers, but fewer videos mentioned the effect on speech performance and soft tissue irritations.

Mesiodistal Angulation of Each Whole Tooth in Patients With Nonsyndromic Unilateral Cleft Lip and Palate: Is it Symmetrical?

OBJECTIVE: To assess the symmetry of the mesiodistal angulations of maxillary and mandibular teeth in patients with unilateral cleft lip and palate (UCLP) and compare with the class I control group without cleft lip and palate (CLP). DESIGN: A retrospective study. SETTING: University department. PATIENTS, PARTICIPANTS: The panoramic radiographs of 45 orthodontically untreated individuals with nonsyndromic UCLP (mean age 14.13 ± 0.75 years) and 45 skeletal class I individuals without CLP (mean age 14.01 ± 0.74 years). INTERVENTIONS: The line passing through the most superior points of the condyles was taken as the reference. The angle between the long axes of the maxillary and mandibular teeth and reference line was measured digitally. With the purpose of determining condylar symmetry, mandibular asymmetry index measurements were utilized. Independent samples t test and paired samples t test were used for the statistical analyses. MAIN OUTCOME MEASURE(S): The mesiodistal angulation of the maxillary and mandibular teeth in patients with UCLP was measured. The differences between the contralateral sides were determined and compared to class I individuals without CLP. RESULTS: No statistically significant difference was found among the condylar asymmetry in both groups (P > .05).The significant differences between the cleft and noncleft sides in the UCLP group was observed in the maxillary central, canine, first premolar and second molar teeth (P < .001, P = .002, P = .013, P = .012, respectively). The mean differences were found to be higher in the central and lateral incisors, canines and first premolars in the UCLP group (P < .001, P = .006, P = .001, respectively). CONCLUSIONS: Although the cleft-side maxillary central incisors tipped in a distal direction in patients with UCLP, the canine and first premolar showed more inclinations toward the mesial direction.

Displacement and stress distribution of Kilroy spring and nickel-titanium closed-coil spring during traction of palatally impacted canine: A 3-dimensional finite element analysis.

OBJECTIVE: To compare the stress distribution and initial displacements during traction of palatally impacted canine between Kilroy and nickel-titanium (NiTi) closed-coil springs by means of the finite element analysis. SETTING AND SAMPLE POPULATION: A finite element method analysis of two traction methods for a maxillary impacted canine. MATERIALS AND METHODS: The corresponding periodontal ligaments (PDLs), brackets, molar tubes and a 0.019 × 0.025-in base stainless-steel (SS) wire were modelled and imported to ANSYS SpaceClaim version 2020 R1. Traction was simulated under two different set-ups with equal force magnitude (60 g); (1) the Kilroy spring, which is made of 0.016-inch SS, and (2) the NiTi closed -coil spring. Von Mises stress distributions and initial displacements of the maxillary teeth were analysed. RESULTS: In both mechanics, while the highest stress was seen on the impacted canine (Kilroy, 10.41 kPa; NiTi closed-coil, 5.27 kPa), the stress distribution decreased as the distance from the impacted canine increased. The Kilroy spring showed a greater total displacement (465.60 µm) on the impacted canine. The higher stresses on the adjacent lateral (5.29 kPa) and premolar (6.41 kPa) occurred with the Kilroy spring. CONCLUSIONS: The Kilroy spring yielded higher stresses than the NiTi closed-coil spring on the impacted canine and the adjacent teeth. The difference between distribution of the stresses over the impacted canine induced greater displacement with the Kilroy spring, particularly in the vertical direction.

Effect of facial profile convexity on the perception of mandibular asymmetry using three-dimensional stereophotogrammetric images.

OBJECTIVE: The aim of this study was to test the hypothesis that sagittal anomalies have an effect on the perception of mandibular asymmetry. Secondly, it aimed to determine the asymmetry perception threshold of orthodontist and laypeople. SETTING AND SAMPLE POPULATION: A total of 90 individuals were included in the study from different professions (Orthodontist: n:45, layperson: n:45). MATERIALS & METHODS: The reference image was obtained with 3dMD device and selected from among the individuals with class I soft tissue relationship. In the sagittal direction, the chin area has been moved as to produce 5 and 10 degrees of change in facial convexity angle. Similarly, 0, 2, 4, 6, 8 and 10 mm changes were made and recorded in video format. Manipulated images were scored by participants with VAS method. RESULTS: When differences between the groups were evaluated, the reference image was scored similarly by orthodontists and layperson (P: .017). No statistically significant difference was observed between the groups in other parameters (P > .05). Asymmetry in 0-2 mm range was evaluated by orthodontist and layperson and statistically insignificant (P > .05). Similarly, the change between 8 mm and 10 mm was different in both groups and statistically insignificant (P > .05). Also, when there was no asymmetry, the sagittal direction was differently scored by the participants in both groups and statistically insignificant (P > .05). CONCLUSIONS: It was observed that the effect of sagittal direction changes on asymmetry perception was not statistically significant.

Dental crown symmetry in unilateral cleft lip and palate patients: A three-dimensional analysis on digital dental models.

OBJECTIVES: The purpose of this study was to conduct a 3-dimensional assessment of possible dental crown asymmetry in dental crown shape and/or size that was not clinically visible in unilateral cleft lip and palate (UCLP) patients on the maxilla and mandible and make a comparison to the control group without CLP. SETTING AND SAMPLE POPULATION: The maxillary and mandibular digital models of orthodontically treated 35 individuals with non-syndromic UCLP (mean age: 14.6 ± 2.1 years) and 35 class I individuals without CLP (mean age 14.1 ± 1.5 years). MATERIALS AND METHODS: The crowns of the anterior and posterior teeth were segmented and the teeth on the cleft side were mirrored in UCLP patients considering the arbitrary midsagittal plane as reference. The first alignment was landmark-based and it was followed by the best-fit method. After aligning the images, millimetric differences (deviation analysis) between aligned surfaces were analysed. Independent Samples t test and Mann-Whitney U test were used for statistical comparisons. RESULTS: The highest difference between the cleft side and non-cleft side in the UCLP group was observed in the central incisors (1.85 ± 0.79 mm). The mean difference between the groups in the central incisors was 1.20 mm (95% CI: -1.70; -0.69; P < 0.001). The mean of median values was found to be highest in the central incisors in the UCLP group as 0.72 ± 0.27 mm. It was 0.15 ± 0.05 mm in the control group. CONCLUSION: The difference between the cleft and non-cleft side may exceed 1 mm in the maxillary central incisors of unilateral CLP patients.

Lingual orthodontic treatment: A YouTube™ video analysis.

OBJECTIVES: The aim of this study was to examine the quality of information offered for patients seeking information on lingual orthodontic treatment. MATERIALS AND METHODS: YouTube™ was searched for videos about lingual orthodontic treatment using the key word "lingual braces" from the Google Trends application. One hundred and four videos were selected to be analyzed from the first 120 results. The video content was evaluated using a 10-point score, which was used for classifying low- and high-content video groups. The video information and quality index (VIQI) was applied to determine the quality of the videos. The Mann-Whitney U-test, Chi-square test, and logistic regression analysis were used, and the Pearson correlation coefficient was calculated for statistical evaluations. RESULTS: We classified 32 videos as high-content and 72 as low-content. Most videos were uploaded by laypeople (58.7%, n = 61). Definition of lingual braces and psychological impact were the most commonly discussed topics (51.0%), followed by speech performance (47.1%), pain (44.2%), tongue soreness (37.5%), and biomechanics (14.4%). Compared to the low-content group, the high-content video group had a significantly higher mean number of views (19,867.41 vs 6720.08, P = .002) and more "likes" (135.88 vs 13.01, P < .001), "dislikes" (4.34 vs 0.81, P < .001), and "comments" (26.28 vs 5.31, P = .002). There was no difference in the total VIQI score between the groups ( P = .009). CONCLUSIONS: The content of YouTube™ videos for lingual orthodontics was generally incomplete. Most videos mentioned psychological effects, but few videos discussed the biomechanics or procedure. Orthodontists should be aware of the information available on YouTube™.

Visual perception of faces with unilateral and bilateral cleft lip and palate: An Eye-Tracking Study.

OBJECTIVES: To test the hypotheses that there are differences between orthodontists, individuals with cleft lip and palate (CLP) and laypersons in the visual perception of faces with unilateral (UCLP) and bilateral cleft lip and palate (BCLP), the faces with UCLP and BCLP are visually perceived differently and the hierarchy of visual attention changes when viewing individuals with CLP. SETTING AND SAMPLE POPULATION: Department of Orthodontics and Experimental Psychology at Ege University, Izmir. Sixty images (faces with a social smile and at rest) of 30 volunteers (unaffected controls, UCLP, BCLP) were viewed by 80 participants: orthodontists, individuals with CLP and laypersons. MATERIALS AND METHODS: Eye fixations on four areas of interest were quantified: eyes, nose, upper lip and lower lip-chin. Time to first fixation, fixation before, fixation count and fixation duration parameters were analysed. RESULTS: Orthodontists fixated on the upper-lip area more often than laypersons or individuals with CLP (F2.144 =8.47, P=.00, η²=.19 in faces at rest). The upper-lip area received more fixations (F2.144 =21.93, P=.00, η²=.23) and longer fixation durations (F2.144 =28.86, P=.00, η²=.27) from all participants who gazed on faces with UCLP and a social smile. CONCLUSION: The hypotheses of the study were supported. Orthodontists and laypersons focused more attention on the upper lip and eyes in the resting position, respectively. The upper-lip area of the BCLP images captured more attention at rest.

Three-dimensional evaluation of social smile symmetry.

OBJECTIVE: To evaluate the social smile symmetry using three-dimensional (3D) stereophotogrammetric images. MATERIALS AND METHODS: The study was conducted with 3D facial images of 30 individuals (age range 13-25 years). The rest position was considered as the reference image and the social smile image was aligned on this image using the best-fit alignment method. The spatial differences between the same points established on both images using 3D analyses were determined for right and left points in X, Y, and Z planes. RESULTS: The highest difference related to spatial distance in right and left points was -0.56 mm (95% confidence interval [CI], -1.19, 0.06 mm) between right and left commissure (Com) points. The difference was not significant, and the Bland-Altman upper and lower limits were -3.85 mm and 2.71 mm, respectively. The highest difference for the transversal plane was found in Com points, similarly to the spatial distance (mean: 0.50 mm, 95% CI, -2.62, 1.02 mm). The differences between the changes in the left and right points in the Y and Z plane were not significant (P > .05). CONCLUSIONS: The social smile was observed to show asymmetry in varying amounts in the different directions. Asymmetry increases in some cases, specifically for the corners of the mouth.

How are faces with increased and decreased lower facial height perceived visually?

OBJECTIVE: The aim of this study was to assess how faces with different lower facial height (LFH) were visually perceived by laypersons using eye-tracking technology. MATERIALS AND METHOD: A total of 48 facial images of volunteers with different LFH (normodivergent, hypodivergent, hyperdivergent) were randomly viewed by 50 participants (25 male, 25 female) using Tobii Eye Tracker (Tobii T60, Tobii Technology AB, Sweden). Facial images with normal lower anterior facial height (LAFH) were used as the control group. All images were divided into three areas of interest (AOI): eyes, nose, and lower face. Eye movements of participants were analyzed with Tobii Studio software (version 3.3.1, Tobii Technology). Time to first fixation (TFF), fixation before (FB) (initial attentional capture), fixation duration (FD), and fixation count (FC) (sustained attention) parameters were measured and compared between image groups. Repeated measures ANOVA, independent samples t test, and intraclass correlation coefficient (ICC) were used for statistical analysis. RESULTS: In all image groups, the eyes were the most remarkable area that was looked at most and longest. A significant main effect was revealed for TFF on the lower face area between image groups: F (2.98) = 9.61, P = 0.00, η2 = 0.164. The lower face area of the hyperdivergent images was found to capture initial attention faster than that of the other images. A significant main effect was revealed for FD on the lower face area between image groups: F (2.98) = 22.98, P = 0.00, η2 = 0.319. CONCLUSIONS: Increased and decreased LFH affected visual perception. The difference in LFH did not alter the hierarchy of visual perception.

Three-dimensional evaluation of morphologic tooth symmetry in various malocclusions.

INTRODUCTION: The aim of this study was to evaluate the morphologic symmetry of the maxillary and mandibular teeth between the left and right quadrants in 3 dimensions using advanced engineering software. METHODS: The total sample comprised 120 dental casts of 60 patients with dental and skeletal Class I, Class II, and Class III malocclusions. They were divided into 3 groups of 40 dental casts (20 maxillary, 20 mandibular) belonging to 20 patients. The dental casts were digitized with an intraoral 3-dimensional scanner (TRIOS; 3Shape, Copenhagen, Denmark). Segmentation and superimposition procedures were carried out using Rapidform software (Inus Technology, Seoul, Korea). Teeth in the left and right quadrants (except for the second molars) in both jaws were superimposed using 3-point registration followed by surface-based registration; 3-Matic software (Materialise, Leuven, Belgium) was used for deviation analysis. RESULTS: The maximum mean deviations observed in the positive and negative directions were 0.14 ± 0.10 mm in the maxilla (for the Class I group) and 0.16 ± 0.09 mm for the Class III group. The differences of the maximum deviation amounts among the malocclusion groups were 0.47 ± 0.08 mm in negative direction in the maxillary teeth and 0.79 ± 0.17 mm in the mandibular arch. CONCLUSIONS: In the 3 malocclusion groups investigated, morphologic deviations were low and clinically insignificant. Symmetry of tooth morphology did not differ among Class I, Class II, and Class III malocclusions.

Three-dimensional analysis of tooth movements after palatal miniscrew-supported molar distalization.

INTRODUCTION: The aim of this prospective clinical study was to evaluate the dentoalveolar effects of a palatal miniscrew-supported molar distalization appliance using a 3-dimensional reverse engineering method. METHODS: This study sample comprised 21 patients at an average age of 13.6 years with a bilateral Class II molar relationship. Distalization was performed using skeletal anchorage. Dental casts were obtained just before treatment and after appliance removal, and they were scanned with a 3-dimensional dental scanner. The digital dental cast images were aligned. Four points and 2 lines were determined on each tooth, and the correlations between tooth movements and the linear and angular changes were analyzed 3 dimensionally. RESULTS: In the sagittal direction, the first molars showed a mean linear movement of 4.10 ± 1.57 mm, with distal tipping of 11.02°; the central incisors showed a mean distal movement of 0.95 ± 0.40 mm, with retroclination of 1.59 ± 0.59°. In the vertical direction, only the first molars showed intrusion, with a mean value of -0.59 ± 0.50 mm. Rotation of the first molars was 4.92° ± 3.09°. The second molars had the greatest rotation. The highest correlation among tooth movements was found between the first and second molars. CONCLUSIONS: Through support from the anterior palatal region, the maxillary first molars were distalized without anchorage loss. Furthermore, movement was observed in all 3 planes of space with reduction from the posterior to the anterior in the maxillary arch.

Effects of rapid maxillary expansion on facial soft tissues : Deviation analysis on three-dimensional images.

OBJECTIVE: Changes in soft tissue in various morphological regions of the face immediately after rapid maxillary expansion (RME) were examined using three-dimensional (3D) deviation analyses. PATIENTS AND METHODS: A total of 50 patients were included in the study; 25 patients (11 female and 14 male) presented with a unilateral or bilateral posterior crossbite malocclusion requiring RME. In addition, 25 patients (13 female and 12 male) were included as a control group. The mean ages of the study group and control group were 9.8 years (range 8.1-12.6 years) and 9.6 years (range 8.3-12.2 years), respectively. The 3D stereophotogrammetric images acquired immediately before the appliance was cemented and after expansion had been completed in the treatment group were compared using Rapidform software. The 3D deviation analyses were made for the complete face and in the upper and lower face, upper and lower lips and nose regions. The amount of negative and positive deviations and the mean deviations were examined on the facial meshes for the 95th percentiles. RESULTS: Immediately after RME, the mean absolute deviation over the complete face was 0.54 ± 0.16 mm. The mean change for the upper face was 0.42 ± 0.17 mm (mean positive deviation: 0.37 ± 0.17 mm; mean negative deviation: -0.48 ± 0.18 mm). The mean absolute deviation was 0.62 ± 0.28 mm in the upper lip and 0.60 ± 0.34 mm in the lower lip. In the nose area, the absolute deviation was 0.41 ± 0.21 mm (mean positive deviation: 0.39 ± 0.16 mm; mean negative deviation: -0.43 ± 0.26 mm). CONCLUSIONS: Changes in facial soft tissues in the upper face, lower face, nasal soft tissues, and lower and upper lip regions were observed after RME.

Reproducibility of the lip position at rest: A 3-dimensional perspective.

INTRODUCTION: In this study, we evaluated the reproducibility of the lip position at rest in 3 dimensions using reverse engineering software and stereophotogrammetric images. METHODS: We used 3dMD Flex (3dMD, Atlanta, Ga) to obtain 60 stereophotogrammetric images from the same participant. Thirty images were obtained in 3 sessions on the same day, and the procedure was repeated 6 weeks later for 30 more images. The surface-base registration, the segmentation of the upper and lower lips, and the 3-dimensional deviation analysis were performed with Geomagic Control (3D Systems, Rock Hill, SC) software. The Shapiro-Wilk test, paired sample t test, Bland-Altman plots, and Wilcoxon signed rank test were used for statistical analysis at a significance level of P <0.05. RESULTS: The deviations of the upper lip on the first images were between 0.16 and 1.39 mm. The mean total deviation was 0.25 ± 0.12 mm. The mean deviation of the lower lip was 0.34 ± 0.17 mm. The deviations were observed between -1.96 and 1.97 mm. When the mean positive (P = 0.633 and P = 0.171, respectively) and the mean negative (P = 0.771 and P = 0.842, respectively) deviations of the upper and lower lips were analyzed, there was no significant difference between the 2 time points. CONCLUSIONS: The results suggest that the rest position can be reproduced within a small range both on the same day and between the sessions. More research with larger samples is needed to confirm these results.

Social smile reproducibility using 3-D stereophotogrammetry and reverse engineering technology.

OBJECTIVE: To assess the range of social smile reproducibility using 3-D stereophotogrammetry and reverse engineering technology. MATERIALS AND METHODS: Social smile images of white adolescents (N  =  15, mean age  =  15.4 ±1.5 years; range  =  14-17 years) were obtained using 3dMDFlex (3dMD, Atlanta, Ga). Each participant was asked to produce 16 social smiles at 3-minute intervals. All images were obtained in natural head position. Alignment of images, segmentation of smile area, and 3-D deviation analysis were carried out using Geomagic Control software (3D Systems Inc, Cary, NC). A single image was taken as a reference, and the remaining 15 images were compared with the reference image to evaluate positive and negative deviations. The differences between the mean deviation limits of participants with the highest and the lowest deviations and the total mean deviations were evaluated using Bland-Altman Plots. RESULTS: Minimum and maximum deviations of a single image from the reference image were 0.34 and 2.69 mm, respectively. Lowest deviation between two images was within 0.5 mm and 1.54 mm among all participants (mean, 0.96 ± 0.21 mm), and the highest deviation was between 0.41 mm and 2.69 mm (mean, 1.53 ± 0.46 mm). For a single patient, when all alignments were considered together, the mean deviation was between 0.32 ± 0.10 mm and 0.59 ± 0.24 mm. Mean deviation for one image was between 0.14 and 1.21 mm. CONCLUSIONS: The range of reproducibility of the social smile presented individual variability, but this variation was not clinically significant or detectable under routine clinical observation.