Smile Index Research Articles

Evaluation of smile esthetics in adults with different overjets

Our aim was to quantitatively assess the relationship of smile esthetics variables with various types of anterior overjet (OJ) malocclusion, and identify the cephalometric factors affecting smile measurements in different types of anterior overjet malocclusion. 90 patients undergoing orthodontic treatment in the Department of Orthodontics were selected for this retrospective study based upon the inclusion criteria. The patients were divided into the following groups according to their OJ: Group 1 (0-4mm), Group 2 (>4mm), Group 3 (<0mm).The upper lip height, and inter-labial gap differed significantly among the groups, whereas arc ratio, tooth number, upper midline, buccal corridor, smile index, arch form index and lower tooth exposure did not significantly among the groups. Some smile variables (upper lip height, inter-labial gap) differed significantly among different types of anterior overjet malocclusion. This study confirmed that the smile pattern varies between different types of malocclusion.

Morphological features of smile attractiveness and related factors influence perception and gingival aesthetic parameters

IntroductionIn addition to understanding the basic standards of a smile and patient's opinion, dentists should take into account smile aesthetics, an essential factor for optimal outcomes. This study aimed to evaluate the factors that affect the perception of an aesthetic smile and determine its morphological characteristics and measure the gingival aesthetic parameters. MethodsIn all, 200 Vietnamese aged 18-35 years were recruited to have their spontaneous smiles captured. These smile images were assessed by 50 laypersons and 50 dentists using a visual analogue scale measurement. The images were analysed to evaluate perceptions of evaluators, determine smile attractiveness, and measure gingival aesthetics. ResultsThe difference in the judgements of laypersons and dentists, males and females, and laypersons aged 18-25 and 26-35 years were nonsignificant. High or average anterior smile line, parallel smile arc, upward upper lip curvature, second premolars as the posterior-most teeth displayed, smile index of 5.23-5.63, and dynamic smile symmetry of 1 were scored highly on smile attractiveness. The following maxillary gingival aesthetic parameters were preferred: gingival zenith (GZ) of the canine 0.72-0.75 mm apical to the GZ of the central incisor; GZ of the lateral incisor 0.66 mm coronal to the gingival line; gingival line angle of ∼87°; for the central incisor, lateral incisor, and canines, distance from the GZ to the long axis of 1, 0.4, and 0 mm, respectively; interdental papilla height of 4.25, 3.60, and 3.85 mm, respectively; ratio of the distance from the GZ and the interdental papilla tip to the incisal edge of ∼1.74-1.77 mm. ConclusionsFactors including profession, gender, and age of evaluators had almost no impact on their perception of aesthetics. Smile attractiveness characteristics and gingival aesthetic parameters have clinical applicability for patient care.

An orthodontic analysis of the smile dynamics with videography

Background and objectivesSmile is one of the most effective means by which people convey their emotions. The objective of this study was to capture, analyse and measure the parameters through videos clips for studying the dynamics of posed and unposed smile and to measure the parameters through video clips for studying the dynamics of speech. MethodologyA total of 100 subjects seeking orthodontic treatment with Angle’s Class I malocclusion were included in the study. The principal investigator selected the frames for speech and a panel of five members selected the appropriate frames for posed smile and unposed smiles. Frames after videography were used for measurements. Parameters like Maximum incisor exposure, Lower lip to upper incisor, Gingival exposure, Inter-labial gap etc were measured in “mm” for posed and unposed smile frames. Categorical data was compared using McNemar’s test. p ​< ​0.05 was considered significant. ResultsThe median of maximum upper incisal exposure (p ​= ​2.2e-16), lower lip to upper incisor (p ​= ​2.422e-13A), inter-labial gap (p ​= ​2.2e-16 A), smile width (p ​= ​5.212e-16 A) and smile index were significant (p ​= ​0.0001 A). There was a significant change from not exposed to exposed gingival exposure over posed smile to unposed smile (p ​= ​0.0008). The most posterior maxillary tooth visible in the posed and unposed groups were the second premolars in 57% and 74% patients, respectively. In both the smile groups, 55% of subjects exhibited a consonant smile. ConclusionIt can be concluded that the information obtained from the current video graphic study can be used as a guideline for the diagnosis and as a part of comprehensive treatment planning.

Evaluating upper lip changes during smiling and at rest in Indian population.

Smile aesthetics is one of the major goals to be achieved after orthodontic mechanotherapy as it visibly displays the results of orthodontic treatment. Although orthodontic retainers aid in maintaining post-treatment occlusion, soft tissue function and aesthetics, appropriate knowledge of smile changes with age can help orthodontists to obtain stable and aesthetically appealing treatment results. To assess and quantify soft tissue changes in the upper lip in vertical dimension at both repose and maximum smiling and to evaluate changes occurring with the smile index and upper lip with age and sex in subjects of Indian origin. Department of Orthodontics and Dentofacial Orthopaedics, Army College of Dental Sciences, Secunderabad, Telangana, India. Observational study. A total of 160 volunteers (80 males and 80 females) selected and were divided into 4 groups according to age and were further divided into 2 sub-groups according to gender. Thirteen measurements of relaxed and smiling upper lip were taken with a calibrated metal ruler and divider directly on the subjects. Analysis of variance (ANOVA) was done followed by post hoc test to determine which groups were significant from others. Levene's test was done to assess equality of variance and t-test for equality of means was done. Statistically significant results were obtained in between groups and sub-groups for parameters like smile index, upper lip elevation while smiling and smile pattern in males and females changing with increase in age. High smile patterns with more vertical smile are more common among females and low smile patterns are more common among males. With age, the smile tends to be more horizontal in both genders.

Perception and Characterization of Posed Smile: A Photographic Study

Aims of the Study:The aims of the study are: (a) to compare the perceptions of dental specialists and laypeople regarding smile esthetics; (b) to compare male and female smile parameters; (c) to find influence of smile parameters on esthetics of smile.Materials and Methods:The study was conducted on 60 subjects (30 males and 30 females) of age 18 to 25 years. Frontal posed photographs of all subjects were taken using a digital camera and rated on a visual analog scale by 10 dental specialists and 10 laypersons. Measurements made on photographs were used to analyze various parameters of smile, such as buccal corridor space, smile arc, modified smile index, anterior height of smile, most posterior maxillary tooth visible, and midline relationship of central incisors to philtrum.Results:Visual analog scale values showed that 6 photographs were rated as very good (3 males, 3 females), 29 as good (11 males, 18 females), 21 as average (13 males, 8 females), and 4 photographs were rated as bad (3 males, 1 female). A high correlation was observed between ratings of dental specialists and layperson’s ratings for both male and female smiles. Most of the subjects had non-consonant smile arc, and a high correlation was found between buccal corridor space on right and left sides in both males and females. Most of the male and female smiles had an average anterior height of smile; permanent maxillary first molar was the last tooth visible during smile (73.3% females, 66.7 males); and 55% subjects had coincident midline relationship of central incisors to philtrum.Conclusion:There was no significant difference in perception of dental specialists and laypersons regarding esthetics of smile. Smile arc and anterior height of smile influenced the esthetics of smile. No significant difference was found between male and female smile parameters except modified smile index.

Three-dimensional evaluation of smile characteristics in subjects with increased vertical facial dimensions

Patients seeking orthodontic treatment often have esthetic concerns (ie, they want a better smile). Patients with increased vertical facial dimensions have different smile traits than other patients. This study aimed to compare the smile characteristics of subjects with different vertical facial dimensions and to use stereophotogrammetry to evaluate the changes in facial animation upon smiling. One hundred twenty adolescents and young adults (aged 15-25years) who were referred for orthodontic treatment were divided into 2 groups according to their vertical facial height: increased (n=30) and normal (n=30). Three-dimensional stereophotogrammetric images were obtained from the patients during rest and smile. The images were superimposed, and the displacements of specific landmarks were recorded. Linear, angular, and proportional measurements were recorded on the smile and rest images. When smiling, horizontal movement of commissures was less (right, P=0.038; left, P=0.009), upper lip elevation was higher (P=0.014), and the upper lip was shorter (P=0.014) in the vertical group than in the normal group. In the vertical group, the interlabial gap was increased both at rest and when smiling (P<0.001). Statistically significant differences were found in smile index (P=0.001), nasolabial fold displacement (P=0.018), and lip angles (both P=0.001) between groups. Group and sex differences were observed when smiling. Careful consideration of these differences will help clinicians in proper diagnosis and treatment planning.

Smile outcome comparison of Invisalign and traditional fixed-appliance treatment: A case-control study

The purpose of this study was to evaluate and compare smile treatment outcomes between patients treated with Invisalign clear aligners (Align Technology, Santa Clara, Calif) and those treated with traditional fixed appliances by integrating variables such as lip symmetry, smile index, smile cant, buccal corridors, and gingival display into smile outcome evaluation. Records from 58 patients, 29 of whom received Invisalign treatment (mean age 19.03years) and 29 of whom received traditional fixed-appliance treatment (mean age 13.83years), were compared for their smile outcome. Pretreatment scores, posttreatment scores, and differences between within-group smile score before and after treatment were determined for each group. Fifteen variables comprised the smile outcome, and the data were analyzed with the Mann-Whitney U test and the Wilcoxon t test for 2 dependent samples. Six variables within the fixed-appliance group presented with better smile scores than those within the Invisalign group; buccal corridors (%) (mean difference=8.42%), buccal corridors (mm) (5.35mm), smile cant (0.42°), maxillary dental midline (0.21mm), gingival display (0.56mm), and smile index (1.09%) for P<0.05. Invisalign performed better on 2 variables that determined maxillary incisor position (1.26mm) and inclination (2.09°). No significant difference (for P=0.05) was shown between pretreatment and posttreatment scores for either of the 2 groups. Using the 15 variables in this study, the results suggested that for patients with Class I nonextraction, treatment with traditional fixed appliances changes the patient's smile more than Invisalign treatment, and fixed appliances appear to be more effective in improving the variables that quantify posttreatment smile outcome.

Smile Aesthetics among Late Adolescents: Perspective of Adolescents, General Dentists and Orthodontists

Introduction: An adolescent’s personal experiences, peer influences and social environment can affect their preference towards smile aesthetics and have influence apart from the opinion of their orthodontists. Aim: To evaluate and compare the preferences regarding smile arc, gingival display, midline symmetry, shape and size of incisor teeth, buccal corridor space and smile index of adolescent subjects between late adolescents, general dentists and orthodontists. Materials and Methods: A total of 52 orthodontists, 111 general dentists and 275 adolescents (156 females, 119 males) had participated in this cross-sectional study from 1st September 2019 to 31st January 2020. Each participant was shown a photo album consisting of 5 sets of photographs of male and female adolescent subjects and was asked to rate them on 7 selected variables. The data obtained was subjected to comparison between the groups using Chi-square test. Results: While assessing smile of the female subject, other than the incisal edge position, the intergroup comparisons of gingival display (p=0.0001), midline symmetry (p=0.0001), shape of incisor teeth (p-value=0.0001), buccal corridor space (p=0.001), ratio of central: lateral incisor (p=0.016) and smile index (p=0.0001) were statistically significant. While assessing smile of the male subject, the intergroup comparisons of incisal edge position (p=0.0001), gingival display (p=0.001), midline symmetry (p=0.007), shape of incisor teeth (p-value=0.0001), buccal corridor space (p=0.0001), ratio of central: lateral incisor (p=0.0001) and smile index (p=0.0001) were statistically significant. Orthodontists’ accepted gingival display of 0-2 mm, midline deviation up to 2 mm and buccal corridor space of upto 5 mm and upto 25% increase in smile index in both genders. Conclusion: The Orthodontists and dentists have more similarities than differences in comparison to adolescents with respect to the smile preferences of adolescent subjects.

Effectiveness of the increase of the occlusal vertical dimension in the smile of young Peruvian adults: A quasi-experimental study

Aim: To evaluate the increase of the occlusal vertical dimension (OVD) on the smile in young Peruvian adults. Materials and Methods: This quasi-experimental study included a total of 30 subjects (15 men and 15 women) aged between 20 and 30 years. Silicone stops were created that increased the OVD by 2 and 4 mm. Photographs were taken with a reflex camera of position, at programmed and standardized lighting, with and without the stops made to the patients using a head and face positioner. The following measurements were made: smile index, interlabial distance, intercomisural width, distance of the incisal edge–upper lip, and distance of the incisal edge–lower lip. The analysis of variance test was used for statistical analysis, establishing a level of significance at P < 0.05. Results: The measure of the interlabial distance of the initial smile was 10.70 ± 2.80 mm, in which the OVD became 11.79 ± 3.67 mm with the increase of 2 mm and 12.91 ± 3.98 mm with the increase of 4 mm; however, the increase in OVD favored a decrease on the smile index, decreasing from 6.07 ± 1.51 mm to 5.48 ± 1.24 mm and 4.99 ± 1.47 mm in the group of increases in the OVD of 2 and 4 mm, respectively. Conclusion: The increase of the OVD favors an increase in the interlabial distance and the measure from the incisal edge to the lower lip; however, it produces a decrease in the smile index in the young Peruvian patients evaluated.

Influence of occlusal vertical dimension on lip positions at smile in completely dentulous adults.

Aim:The study was conducted to evaluate the effect of increased vertical dimension on the lip positions at smile in dentulous subjects.Settings and Design:Invivo - comparative study.Materials and Methods:Thirty individuals aged between 22 and 30 years were selected for the study. Poly-vinyl siloxane (Jet Bite, Coltene, Switzerland) interocclusal bite records of varying thickness of +1, +2, +3, and +4 mm were made using articulated stone casts for all the participants, respectively. Posed smile photographs at different increased vertical dimensions of +1, +2, +3, and +4 mm were captured with D-SLR camera (Nikon D3200 of 18 megapixels with macro lens, Japan) mounted on tripod stand keeping a uniform distance of five feet from the face. Head positioning device (Genoray CBCT Machine Papaya 3D Plus, Unicorn DenMart, India) was used to stabilize the head position of the participants. Interlabial gap height, intercommissural width, smile index (width/height ratio), incisal edge-to-upper lip distance, incisal edge-to-lower lip distance, and display zone area measurements were made in AutoCAD software (Autodesk, Inc., California, USA).Statistical Analysis Used:One-way repeated measures ANOVA tests (α = 0.05) and Bonferroni's post hoc tests were performed for statistical analysis.Results:With increasing occlusal vertical dimension, the interlabial gap height, incisal edge-to-lower lip distance, and display zone area increased significantly (P < 0.001). The smile index decreased significantly as the occlusal vertical dimension increased (P < 0.001). No significant difference was found in intercommissural width and incisal edge-to-upper lip distance.Conclusion:It was found that an increase in occlusal vertical dimension led to an increase in interlabial gap height, incisal edge-to-lower lip distance, and display zone area measurements, whereas the width of smile and incisal edge-to-upper lip distance did not change with increasing occlusal vertical dimension.

A Comparison of Facial Proportions in Pleasing and Unpleasing Smile Photographs from Nepalese Population

Introduction: Facial proportion and dental proportions are matters of interest for dental professionals to craft a beautiful smile. In facial analyses, the role of different proportions cannot be overlooked when planning dento facial treatment. This study aims to determine the different facial proportions; smile index, lower smile index, nose width to outer inter commissural width, intercanine width to outerinter commissural width, nose width to intercanine width and outer intercommissural width to lower facial height in esthetically pleasing smile (ES) and esthetically unpleasing smile (US) groups.&#x0D; Materials and methods: The frontal smiling photographs (N=152, 74 pleasing and 78 unpleasing smile) were gathered and different linear measurements were carried out using digital ruler. The facial proportions were derived and comparisons were made amongst groups and differences were examined in comparison to standard accepted proportion (such as Golden proportion).&#x0D; Results: Average smile index of ES (5.899±1.201) was lower than that of US group (6.421±1.675).The golden proportion was not valid for smile indices in each group. Mean nose width to intercanine width ratio significantly differed in ES and US. The outer inter commissural width to lower facial height was not statistically significantly different from 1:1 ratio.&#x0D; Conclusion: Most facial proportions in pleasing and unpleasing smiles showed no difference. The outer intercommissural width to lower facial height was found in 1:1 proportion current study with possible utilization in determining vertical dimension of occlusion.

Evaluation of Smile Parameters in Nongrowing Subjects Using Photographs

Abstract Introduction An attractive or pleasing smile enhances the acceptance of an individual in the society by improving interpersonal relationships. In this new era of social media, people are more concerned about their smile; hence, smile esthetics has become the primary objective of orthodontic treatment. It is seen that various smile parameters change with age and gender. Aim The aim of the study was to evaluate various smile parameters in nongrowing patients using photographic analysis. Materials and Methods The sample comprised photographs of 50 subjects (8 males, 42 females) taken in natural head position and then divided into two age groups: Group I (25 subjects, aged 18–20 years) and Group II (25 subjects, aged 23–29 years). The various parameters were analyzed using Adobe Photoshop software (version CS 6; Adobe System Inc., California, United States): upper lip and lower lip lengths during rest and smiling, smile index, buccal corridor, upper and lower lip thickness, interlabial gap, incisal display, widest visible maxillary display, and intercommissural width. Results The results showed that lower lip length at rest and smiling, interlabial gap, incisal display, inner commissure width, and widest visible maxillary display were increased, whereas upper lip length both at rest and smiling, upper and lower lip thickness, outer commissure width, smile index, and buccal corridor were decreased with age. Statistically significant sex-related differences were found in upper lip length at rest and lower lip length both at rest and smiling. Conclusion Orthodontic treatment must incorporate various esthetic elements of smile to achieve desirable results.

Lip position analysis of young women with different skeletal patterns during posed smiling using 3-dimensional stereophotogrammetry.

The aim of this study was to explore the internal relationship between posed smile characteristics, lip position, and skeletal patterns in young women. Fifty women between the ages of 20 and 30years were enrolled and divided into 3 groups-vertical, average, and horizontal patterns- using the following parameters: FMA, GoGn-SN, and Jarabak ratio. Each subject was scanned in natural head position and with a posed smile. The interlabial gap, intercommissural width, and smile index were calculated. The frontal region was selected as the reference plane for superimpositions. The changes of the lip landmarks in the vertical, sagittal, and coronal directions were investigated. The smile indexes were listed in the following sequence: vertical<average<horizontal. Significant differences were found in the interlabial gap among the 3 groups. Compared with the average and horizontal groups, the upper lip landmarks of the vertical group showed differences and changed more only in the vertical direction. However, the lower lip landmark showed no differences in any direction. Different skeletal patterns have characteristic smile features. The vertical skeletal pattern affects upper lip movements because there is more space for upper-lip elevation. However, the vertical skeletal pattern has no effect on lower lip movement.

Evaluation of Smile Characteristics in Three Different Sagittal Malocclusions Before and After Nonextraction Orthodontic Treatment.

Introduction:To investigate the smile esthetics variables in three malocclusion classifications of angle to find out if the final smile esthetics was correlated with the initial types of malocclusion.Materials and Methods:This cross-sectional study was performed on 90 adult patients (18–28 years old) with three classes of malocclusion (n = 30 for each class), who were just treated by an orthodontist based on standard edgewise (0.018 inch). A standardized smile mesh analysis was used to evaluate seven smile characteristics.Results:Orthodontic treatment improved all the smile characteristics in the three groups. All groups showed an increase in smile width, smile index, and vertical indices; while, the transverse indices decreased. Significant increase was observed in four smile measurements in patients with Class II malocclusion. Comparing the smile characteristic changes among the three groups revealed that the changes induced by orthodontic treatment were significantly higher in patients with Class II malocclusion.Conclusion:The smile esthetics in all the three types of malocclusion benefited from the orthodontic treatment; however, the changes were more significant in Class II malocclusions. None of the three malocclusion types showed significant difference between the pre- and post-treatment smile characteristics.

Esthetics and smile-related characteristics assessed by laypersons.

This study aimed to identify the characteristics of full-smile images assessed by laypersons using visual analog scale measurement. A total of 176 young Chinese subjects (88 males and 88 females; 20-35 years of age) with healthy dentogingival tissue were recruited to have their dynamic smiles captured using digital technology. A full-smile frame image of each subject was selected and evaluated by 22 laypersons (11 males and 11 females; 20-35 years of age) using visual analog scale measurement. Unattractive and attractive groups were designated according to the 25th percentile and 75th percentile of average visual analog scale score for the subjects, respectively. Eight smile variables were used to measure the characteristics of the full-smile images. Pearson's Chi-square test and unpaired t tests were used to analyze the data with significance level α = 0.05. The visual analog scale measurement scores of unattractive and attractive subgroups, respectively, were 37.89 ± 2.12 and 50.67 ± 2.75 (male subjects), and 37.14 ± 2.80 and 51.92 ± 1.99 (female subjects). VAS scores were significantly different between subgroups for both male and female subjects (P < .001). No significant differences were observed between male and female subjects (P > .05). Attractive full-smiles in young Chinese subjects demonstrated higher frequencies of average or low anterior smile line, average or low posterior smile line, upward upper lip curvature, and "broad and short" smile with high smile index. The smile variables of anterior smile line, posterior smile line, upper lip curvature, and smile index are predominant factors of smile attractiveness, which should be given priority to consider and manage in the anterior esthetic treatment plan.

Dynamic Smile Visualization and Quantification in different age groups

Abstract Aims and Objectives: To assess the posed and dynamic smile and to compare the various attributes of smile in frontal, oblique and sagittal dimensions, in two different age groups (10- 15years and 18-25 years). Materials and Methods: The posed and dynamic smile parameters were measured using digital video clips in 80 subjects of two different age groups (10-15years and 18-25 years). Total of 15 parameters were studied in 3 planes of space. The data was analysed using student`s t-test to compare smile parameters across the age groups, paired t-test was used to analyse the parameters of posed and unposed smile within the same age group and chi-square test was performed for the discrete data. Results: The present study revealed significant differences in dynamic smile parameters between the two age groups. The parameters like Philtrum height and Smile index are more in older age group whereas the buccal corridor was more in younger age group. Significant differences were also recorded in various parameters in both the groups when the posted smile is compared with that of the dynamic smile. Conclusion: In both the age groups, the dynamic and posed smile attributes are significantly different, except for buccal corridor and interlabial gap.

Subjective and objective evaluation of frontal smile esthetics in patients with facial asymmetry-a comparative cross-sectional study.

To analyze the relationship between subjective and objective evaluations of pre-treatment posed smiles in patients with facial asymmetry and to assess the influence of dentofacial structures involved in asymmetry on the perception of smile attractiveness. Thirty-five patients (25 males and 10 females) between 18 and 25 years of age with facial asymmetry were selected. Pre-treatment clinical photographs of posed smiles were subjectively evaluated by a panel of 20 orthodontists, 20 oral surgeons, and 20 laypersons. A customized Smile Mesh program was used for objective evaluation of the same smiles. Direct comparison among three smile groups (unattractive, slightly attractive, and attractive) for different Smile Mesh measurements was carried out using two-way anova test. Additionally, linear regression was performed to evaluate whether these measurements could predict the attractiveness of captured smiles. Patients with 'slightly attractive' smiles had a significantly greater distance between the incisal margin of the maxillary central incisor and the lower lip during smiling. The Smile Index was significantly greater in attractive smiles. However, based on the coefficients of linear regression, no objectively gathered measurement could predict smile attractiveness. Attractiveness or unattractiveness of smiles in patients with facial asymmetry could not be predicted by any measurement of Smile Mesh. The presence of facial asymmetry did not significantly influence the perception of smile esthetics.

Relationships between soft tissues in a posed smile and vertical cephalometric skeletal measurements.

The purposes of this study were to measure the 3-dimensional parameters of the posed smile and to see whether there are any correlations with vertical cephalometric skeletal measurements. Pretreatment records from a sample of 110 white girls between the ages of 12 and 18years were gathered. The measurements of SN-GoGn, anterior facial height, and lower and upper facial height percentages were obtained from tracing lateral cephalograms. Superimposing the repose and the posed smile facial scans allowed for measurements to be obtained showing the movements in the x, y, and z dimensions of the upper and lower lips, the commissures, and the Cupid's bows. Correlations and multiple linear regression analyses were run to check for associations and predictive relationships between the cephalometric skeletal measurements and soft tissue changes. We found significant moderate correlations and weak correlations. Significant multiple regression models were found for intercommissural width, smile index, and lower lip in the y and z dimensions. There were moderate correlations showing that as SN-GoGn and anterior facial height increased, the interlabial gap increased as the smile index decreased. Significant relationships were found between certain hard tissue cephalometric measurements and the width of the smile as well as the movements of the lower lip.

A study on gingival component of smile

Background: Esthetic enhancement of smile requires prior quantification of gingival component of smile. Hence, a study has been designed on randomly selected volunteers' and posed frontal smiling photographs were taken and analyzed through computer-aided ImageJ software. Aim: To determine the role of gingival component in designing a smile. Settings and Design: Present observational study includes one frontal photograph from each of 212 subjects who were attending the Department of Periodontics (examined during the study period) and then divided into three age groups (18-30, 31-40, and 41-50 years). Materials and Methods: Standardized frontal photographs with posed smile from 212 volunteers irrespective of age and sex were taken and the images were analyzed in computer by using ImageJ software. Statistical analysis used: Mean and standard deviation of intercommissural width (ICW), interlabial gap (ILG), and smile index (SI) during posed smiling were calculated for different sex. Comparison between male and female group were done by Mann-Whitney U test, and P- values were calculated for ICW, ILG, and SI. Spearman's rank correlation coefficients (rho) were calculated for SI and different components of central zone of smile. Results: Male group as compared to female group exhibited greater ICW and ILG, and there was existence of fair to good correlation between lip dynamics and different factors of smile. Conclusion: Present study indicates that different factors of central zone of smile havefair to good correlation with lip dynamics assessed by SI.

共用空間における他者の行為が認知症高齢者の無為に及ぼす影響

This is study on the effect of other people's activities on elderly dementia residents by the behavior tracking survey with automated face recognition technology. 1.The majority of the activities found in the common space were “inaction”, and “conversation”. The expressions in “inaction” had the lowest SI (Smile Index). 2. The higher ability residents had the greater the SI measured. Residents with less ability in ADL exhibited lower SI. 3. This indicates that there is difference in facial expression, though “inaction” seemed a uniformly non-active state. 4. Residents had high SI when watching “ conversation” “conversation and housework” or “caretaker's action”.