Association Between Conf|dence in Smiling and
Esthetic Characteristics
FRANCISCO WILKER MUSTAFA GOMES MUNIZ,MsC*, DENISE JUAC¸ABA CAVALCANTE†,
MARIA MONICA STUDART MENDES MOREIRA,^ PhD‡, LIDIANY KARLA AZEVEDO RODRIGUES,PhD§, CARLOS AUGUSTO DE OLIVEIRA FERNANDES,PhD{, PAULO CESAR DE ALMEIDA, PhD**,
ROSIMARY DE SOUSA CARVALHO,PhD††
ABSTRACT
Objective: This study aimed to analyze which facial, gingival and dental characteristics are associated with conf|dence in smiling among 75 subjects seeking treatment in a northern Brazilian public dental university.
Materials and Methods: Clinical examinations and three standardized photographs of each subject were taken by one trained examiner.In addition, a questionnaire was applied to assess conf|dence in smiling.The subjects were
dichotomized into two groups, non-conf|dent (n536) and conf|dent (n539) in smiling.Chi-square/Fischer exacttest were used to associate the facial, gingival and dental characteristics between groups.
Results: The subjects that reported to be non-conf|dent in smiling were statistically associated with smile type (p50.030) and wrongly positioned teeth (p50.047).On the other hand, gender (p50.491), marital status
(p50.217), gum pigmentation (p50.930), midline (p50.176), volume of the upper (p50.380), and lower (p50.615) lips were not associated with self-reported conf|dence in smiling.
Conclusion: In patients seeking dental treatment in a public dental university, non-conf|dence in smiling was associated only with some oral and intraoral characteristics and not with demographic characteristics.
CLINICAL SIGNIFICANCE
This study showed that only smile type and wrongly positioned teeth were statistically associated with conf|dence in smiling.Dentists should pay attention to those intraoral characteristics, butthe clinical decision making should always include the patients’perception.
(J Esthet Restor Dent 29:E56^E66, 2017)
INTRODUCTION
Smiling represents a facial expression, which varies according to the degree of muscle contracture and it may enhance the acceptance of an individual into society. Smiling plays an important role in facial expressions and it is essential to demonstrate friendliness, pleasantness, and esteem.1,2Many studies showed that unattractive smiles
might be harmful to some individuals, causing not only an unpleasant esthetics, but also psychological
impairments.1,3–5Color, position, teeth shape and size are very important factors to an attractive smile, lips framing, and the amount of visible gingiva are also essential.6 Some characteristics about the ideal smile are reported in the literature.2,5Such characteristics are upper lip
*Post-Graduate Program in Dentistry, Federal University Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
Student Fellow, School of Pharmacy, Dentistry and Nursing, Federal University of Ceara, Fortaleza, Ceara, Brazil `
Professor of Periodontology, School of Pharmacy, Dentistry and Nursing, Federal University of Ceara, Fortaleza, Ceara, Brazil ‰
Professor of Operative Dentistry, School of Pharmacy, Dentistry and Nursing, Federal University of Ceara, Fortaleza, Ceara, Brazil
Professor of Operative Dentistry, School of Pharmacy, Dentistry and Nursing, Federal University of Ceara, Fortaleza, Ceara, Brazil **Professor of the Post-Graduate program in Nursing, Nutrition and Health, State University of Ceara, Fortaleza, Ceara, Brazil
tangent to the upper gingival margin of the maxillary anterior teeth; upper lip curve touching the gingival margin of central incisor and canines; the incisal curve of the maxillary anterior teeth touching the lower lip; lower lip curvature touching the incisal curve of the six upper anterior teeth; central incisor and canines with the same length, and lateral incisor 2 mm shorter; gingiva not appearing, except for the interproximal gingival; the zenith point should reflect the teeth shape and angulations.
Furthermore, the most esthetic smile should have a harmonious relationship among teeth color and form, lips, and gums.7,8All those characteristics should be considered as biologic guideline for restoration, enabling enhancement in the anterior teeth esthetics. The contemporaneous society demands higher standards of esthetics and that is also applied in modern restorative dentistry. Therefore, regarding patients seeking for dental treatment, it is highly important to consider the smile esthetically in a broader way,9leading to the most functionally attractive and well-balanced smile as much as possible. In this context, dentists are able to
harmonize teeth color and shape, modify their position and reconstruct the gingival aspect.10
To fulfill those goals a careful facial and dental analysis must be performed.11In this analysis, it should be included five steps:
1. Facial analysis—overall facial balance;
2. Dental-facial analysis—maxilla and mandible relationship and midline along with teeth lines; 3. Dental-labial analysis—relationship between teeth
and lips;
4. Dental-gingival analysis—relationship between teeth and gums;
5. Dental analysis—shape, position and teeth colors. Tjan et al.5divided the open smile into three
categories: high smile, which reveals the total length of the maxillary anterior teeth and shows a contiguous band of gingiva; average smile displays 75% to 100% of the maxillary anterior teeth and the interproximal gingival only; and lower smile, which reveals less than 75% of the anterior teeth.
However, dental professionals opinions about beauty and attractiveness may not have the same perceptions as the general population.12Due to its subjectivity, the esthetical demand may vary according to cultural and ethnical factors. Therefore, this study aimed to analyze which facial, gingival and dental characteristics are associated with self-reported confidence in smiling in patients seeking for treatment in a northern Brazilian public dental university.
METHODOLOGY
Ethical Aspects
This study was approved by the Institutional Review Board of the Federal University of Ceara under protocol 212/11, and all volunteers signed an informed consent form.
Sample Source and Sample Size Calculation
The Federal University of Ceara is located in Fortaleza, the state capital with approximately 2.5 million inhabitants according to the Brazilian Institute of Geography and Statistics. Fortaleza is the fifth largest capital city in Brazil and more than 95% of the population lives in the urban area. The city has similar habits and behaviors as other Brazilian urban cities. Annually, approximately 500 patients seek for treatment at our institution. Therefore, 15% of this sample (75 subjects) was invited to participate. As a census would not be possible, this percentage was determined arbitrarily. Other studies that used oral health related questionnaires have similar sample sizes.13–15
Sample Selection
For this cross-sectional study, it was included patients of both genders with a range age from 18 to 50 years and with no missing teeth. Subjects that had any history of esthetics procedures in the maxillary anterior teeth, such as surgical crown lengthening and anterior teeth
Clinical Procedures
Three standardized photographs were taken of each subject with a professional photographic camera (Sony Cyber-Shot DSC-F828, Tokyo, Japan) by one
researcher. The researcher positioned in front of the patient with the camera parallel to the subject’s face. To the first photograph, the subjects were requested to remain at rest and do not smile. In the second
photograph, they were asked to smile naturally at their maximum. The subjects that had any difficult in performing this task were requested to over pronounce in Portuguese the letter “I” (the sound closely related to it in English is the letter “E”).3The last photograph taken was intraorally using an expandex lip retractor (Indusbello, Londrina, Brazil). This photograph was taken with the subjects lying in a dental chair.
Smile Characteristics Analysis
The analyses were made by a single trained examiner (DJC). It was assessed dental, labial and gingival characteristics of each subject according to Table 1.
Questionnaire
The questionnaire applied was not previously validated and no attempt to validate it was made in this study. The questionnaire had five structured questions about general esthetics and security aspects regarding smiling. Four of these questions have “yes” or “no” answers. Those questions are:
1. Have you ever evaluated your own smile? 2. Has your dentist ever evaluated your smile?
TABLE 1. Dental, labial and gingival characteristics assessed
Characteristic analyzed Category selection
Smile type Low/High Average
Lip sealing at rest Sealing Non-sealing
Volume of the upper and lower lip Voluminous Medium Thin
Gum pigmentation Pigmented Non-pigmented
Upper lip curve Ascendant Straight Medium
Relation between incisal curve of the maxillary anterior and lower lip on smiling
Following the incisal curve Without parallelism
Last teeth displayed in smile Incisor and canines 1st premolar 2nd premolar 1st molar
2nd Molar
Gingival margin asymmetric between homologous teeth (only incisors and canine were considered)
Absence Presence
Zenith type of all incisors Distalized Centered
Relation between facial midline and dental midline
Coincident Deviated to left Deviated to right
Diastema Absence Presence
Wrongly positioned tooth Absence Presence
Both lateral incisors gingival margin
position in relation to central incisor and canine (esthetic line)
3. Do you feel confident in smiling to other people? 4. Do you see people with beautiful smiles and wish to
have a similar one?
The last question was “What do you want to change in your smile?” This question had multiple answers, such as lip position, lip thickness, gum exposition, gum color, tooth size, tooth color, tooth shape, tooth position, gaps between teeth, others, and none. They were allowed to choose more than one answer. In addition, the subjects’ perception about esthetics in general life and with own smile was numerically assessed. Two questions were made for that purpose: 1. Do you consider esthetic important in your life? 2. Do you like your own smile?
They were instructed to answer from 0 to 10 to both questions. Higher scores mean higher esthetic
importance and more satisfaction with their own smile, respectively.
Statistical Analysis
Results were expressed as absolute or relative
frequencies, means and respective standard deviations (SD), and median with minimum and maximum values reported according to data characteristics.
According to the answer to question “Do you feel confident in smiling to other people?”, subjects were dichotomized into two groups. The subjects that answered “yes” were considered confident in smiling, and those who answered “no” were considered non-confident in smiling. Chi-square/Fisher’s exact tests were used to determine the association between the two groups and all the categorical variables. In addition, Spearmen correlations were performed. Regarding the question “What do you want to change in your smile?”, the subjects were dichotomized into those who wanted to change at least one characteristic in their smile and those who do not. The number of teeth displayed when smiling was categorized into
anteriors plus at least one premolar and anteriors, premolars plus at least one molar. It was also dichotomized the subjects that had or did not have asymmetric gingival margin between homologous teeth of all maxillary anterior teeth.
The subject was considered to have a tooth “wrongly positioned” when any rotation, spacing or absence of alignment between the teeth was noticed. For this outcome, only the anterior teeth were considered. Furthermore, no categorization in the tooth position was applied. To compare confidence in smiling and smile type, it was used the chi-square test. We could not perform this test using low, average, and high smile type separately, as the assumption of the chi-square test could not be achieved. The literature reports that the average smile type is considered to be the most esthetically.5Therefore, low and high smile types were combined to allow comparison, using the appropriate statistical test. All remaining categorical variables in Table 1 were analyzed accordingly. T-test for independent samples was used to assess age difference between groups. Furthermore, Mann– Whitney test was used to compare security in smiling and the non-structured questions about esthetics in general life and with their own smile. The significance level established was 5%. The statistical analysis was carried out with SPSS version 19.0 for Windows (IBMVR
SPSS Statistics, New York, NY, USA).
RESULTS
Among the 75 subjects included in this study, 47 (62.67%) were female and 28 (37.33%) were male with a mean age 33.80610.06 years. Regarding the
ethnicity frequency in this study, 41.3% were white and 49.3% were non-white. The ethnicity was self-reported, and 9.3% of them (n57) did not answer this question. These data were considered as missing.
non-confidents subjects from this study. The associations made between confidence in smiling and the collected variables are available in Table 2.
It was not showed any statistically significant association between confidence in smiling and all the demographic characteristics, such as mean age (p50.190), gender (p50.491), ethnicity (p50.948), and marital status (p50.217). Regarding the structured questions in the questionnaire, it was shown that confidence in smiling was only statistically associated with the question “Do you see people with beautiful smiles and wish to have a similar one?”, as just one non-confident in smiling subject answered “no” to this question (p<0.001). In addition, the
Spearman correlation showed that this association is moderate (r50.414,p<0.001).
Overall, seventy subjects (93.33%) in this study reported a desire to change at least one characteristic
in their smile. The median (minimum; maximum) of characteristics mentioned in both non-confident and confident in smiling groups were, respectively, 2 (1; 4) and 2 (0; 3). In both groups, the most mentioned characteristics (on non-confident and confident in smiling groups, respectively) were teeth color (n529 and 32), teeth position (n514 and 10), teeth size (n511 and 5), and gaps between teeth (n58 and 4). When this question was dichotomized in those who wanted or did not want to change at least one characteristic in their smile, the association was not significant (p50.055). However, the Spearman correlation found that this association is weak and statistically significant (r50.257,p50.026). Both groups reported a high median score to the esthetics importance in their general life, and it was not showed any statistically significant difference between groups (p50.476). On the other hand, the
non-confident in smiling group self-reported a
statistically significant smaller median score about their satisfaction with own smile (p<0.001). This analysis
numerically states that both groups have a different confidence pattern in smiling.
Between the extraoral characteristics analyzed in this study, only the smile type was statistically associated with non-confidence in smiling (p50.03), as more than half of this group (n521) was classified as having either low or high smile. The Spearman correlation,
however, showed that this correlation is statistically significant and weak (r50.251,p50.030) (Table 3). The range of wrongly positioned teeth in the whole-sample varied from none to all anterior maxillary teeth. Twenty-three subjects had at least one anterior wrongly positioned tooth (30.7% of the whole sample). Among those subjects, 22 (95.65%), 16 (69.57%), and 6 (28.09%) had at least one central incisor, lateral incisor, and canines wrongly positioned, respectively. Non-confidence in smiling was found on 65.20% of those
TABLE 2. Association between security in smiling and the demographic characteristics and self-perception oral aesthetic
Non confident in smiling
(n536)
Confident in smiling (n539)
p-Value
Age (mean6SD) 35.47610.37 32.4169.67 0.190*
Gender Maleçn(%) 12 (42.9) 16 (57.1) 0.491#
Femaleçn(%) 24 (51.1) 23 (48.9)
Ethnicity Whiteçn(%) 14 (45.2) 17 (54.8) 0.948#
Non-whiteçn(%) 17 (45.9) 20 (54.1)
Marital status Singleçn(%) 18 (41.9) 25 (58.1) 0.217#
Non-singleçn(%) 18 (56.3) 14 (43.8)
Have you ever evaluated your own smile?
Noçn(%) 3 (37.5) 5 (62.5) 0.714£
Yesçn(%) 32 (48.5) 34 (51.5)
Have your dentist ever evaluated your smile?
Noçn(%) 6 (75.0) 2 (25.0) 0.139#
Yesçn(%) 29 (43.9) 37 (56.1)
Do you see people with beautiful smiles and wish to have a similar one?
Noçn(%) 1 (6.7) 14 (93.3) <0.001#
Yesçn(%) 35 (58.3) 25 (41.7)
What do you want to change in your smile?
No changeçn(%) 0 (0.0) 5 (100.0) 0.055#
Want to chance at least one characteristicçn
(%)
36 (51.4) 34 (48.6)
Do you consider esthetic important in your life?
Median 9.0 9.0 0.476‰
(minimum; maximum) (7.0; 10.0) (7.0; 10.0)
Do you like your own smile?
Median 6.00 8.00 <0.001‰
(minimum; maximum) (0.00; 6.00) (7.00;
10.00)
Legend: *t-test for independent samples;#chi-square;‰Mann^Whitney test;£
TABLE 3. Association between security in smiling and extraoral, and intraoral characteristics
Non confident in smiling
(n536)
Confident in smiling (n539)
p-Value
Smile type High/low 21 (61.8) 13 (38.2) 0.03#
Average 15 (36.6) 26 (63.4)
Lip sealing at rest Sealingçn(%) 34 (48.6) 36 (51.4) 1.000£
Non-sealingçn(%) 2 (40.0) 3 (60.0)
Volume of the upper lip Voluminousçn(%) 4 (30.8) 9 (69.2) 0.380#
Mediumçn(%) 27 (50.9) 26 (49.1)
Thinçn(%) 5 (55.6) 4 (44.4)
Volume of the lower lip Voluminousçn(%) 10 (40.0) 15 (60.0) 0.615#
Mediumçn(%) 23 (52.3) 21 (47.7)
Thinçn(%) 3 (50.0) 3 (50.0)
Upper lip curve Ascendantçn(%) 16 (47.1) 18 (52.9) 0.372#
Straightçn(%) 9 (39.1) 14 (60.9)
Mediumçn(%) 11 (61.1) 7 (38.9)
Relation between incisal curve of the maxillary anterior and lower lip on smiling
Following the incisal curveçn(%)
14 (37.8) 23 (62.2) 0.103#
Without parallelismçn(%) 21 (56.8) 16 (43.2)
Gum pigmentation Pigmentedçn(%) 28 (48.3) 30 (51.7) 0.930#
Non-pigmentedçn(%) 8 (47.1) 9 (52.9)
Last teeth displayed in smile Anterior and at least one premolar teethçn(%)
29 (46.0) 34 (54.0) 0.535#
Anterior, premolars and at least one molarçn(%)
7 (58.3) 5 (41.7)
Gingival margin asymmetric between central incisors
Absenceçn(%) 20 (45.5) 24 (54.5) 0.599#
Presenceçn(%) 16 (51.6) 15 (48.4)
Gingival margin asymmetric between lateral incisors
Absenceçn(%) 16 (44.4) 20 (55.6) 0.544#
Presenceçn(%) 20 (51.3) 19 (48.7)
Gingival margin asymmetric between canines
Absenceçn(%) 12 (41.4) 17 (58.6) 0.362#
Presenceçn(%) 24 (52.2) 22 (47.8)
Cumulative gingival margin asymmetric between anterior homologous teeth
2 gingival margin asymmetric 29 (45.3) 35 (54.7) 0.261#
>2 gingival margin asymmetric 7 (63.6) 4 (36.4)
Right lateral incisor zenith type Centeredçn(%) 27 (50.9) 26 (49.1) 0.428#
Distalizedçn(%) 9 (40.9) 13 (59.1)
Right central incisors zenith type Centeredçn(%) 15 (53.6) 13 (46.4) 0.456#
Distalizedçn(%) 21 (44.7) 26 (55.3)
Left central incisors zenith type Centeredçn(%) 14 (45.2) 17 (54.8) 0.680#
subjects. The chi-square test showed a statistically significant difference between the groups (p50.047). Furthermore, the Spearman correlation was also considered weak and statistically significant (r50.229,
p50.048).
On the other hand, other intraoral important characteristics on esthetic smiling did not show any statistically significant differences, such as presence of at least one diastema (p50.176), last teeth displayed in smile (p50.535), and gingival margin asymmetries between homologous teeth (p50.261). In addition, the association between confidence in smiling and the esthetic line position of both lateral incisors was not statistically significant (p50.089). The Spearman correlation also supports this finding (r50.196,
p50.091).
DISCUSSION
This cross-sectional study aimed to analyzed which extraoral, intraoral and demographic characteristics are associated with self-reported confidence in smiling in
patients of a Brazilian northern dental university. In the modern society, esthetic is able to influence individuals’ quality of life and self-esteem,16possibly leading to changes in the patients’ therapeutics need and,
consequently, in their priorities in a dental treatment.17 Therefore, an esthetical and functionally efficient smile should be the mean goal in modern dentistry.18
However, it is important to consider that the layperson perception in evaluating any oral, gingival or dental characteristics may vary substantially between them and also among dental professionals. Therefore, the decision-making process in any esthetic dental treatment must include the patients’ opinion. The present study showed no statistically significant association between non-confidence in smiling and any demographic characteristics. However, another study, that included subjects with an age range of 16–70, showed that older subjects are less demanding on their smile esthetics.17In addition, this study showed that female subjects had statistically more reasons for dissatisfaction with some smile characteristics than male.17The main reasons to explain these differences are
TABLE 3. Continued
Non confident in smiling
(n536)
Confident in smiling (n539)
p-Value
Left lateral incisor zenith type Centeredçn(%) 25 (45.5) 30 (54.5) 0.464#
Distalizedçn(%) 11 (55.0) 9 (45.0)
Relation between facial midline and dental midline
Coincidentçn(%) 12 (38.7) 19 (61.3) 0.176#
Non-coincidentçn(%) 24 (54.5) 20 (45.5)
Diastema Noçn(%) 27 (44.3) 34 (55.7) 0.176#
Yesçn(%) 9 (64.3) 5 (35.7)
At least one anterior tooth wrongly positioned
Noçn(%) 21 (40.4) 31 (59.6) 0.047#
Yesçn(%) 15 (65.2) 8 (34.8)
Esthetic line of both lateral incisor Both lateral incisor had its esthetic line belowçn(%)
19 (40.4) 28 (59.6) 0.089#
None or only one lateral incisor had its esthetic line belowçn
(%)
17 (60.7) 11 (39.3)
Legend:‰Mann^Whitney test;£
the different age range included in this study (from 18 to 50) and the different questionnaire used in both studies. It is known that after 50 years of age, the aging process starts and, consequently, many facial alterations may arise, leading to loss of facial fullness and decrease tissue elasticity.19Therefore, it is possible to state that the inclusion of older subjects would change these results. In this study, it was showed that the most frequent changes in the smile mentioned by the subjects were teeth colors and their position. These results are in accordance with Akarslan et al.17that reported 55% of dissatisfaction with teeth color and 29.9% worries with anterior teeth crowding in their sample. With these results, it is possible to notice that the constant need to change something in the smile is present in a broader spectrum of patients. At the same time, those who reported to be insecure in smiling were 25.7% more correlated with the desire to change at least one characteristic in their smile.
The smile type is another important aspect in esthetic smile and in this study was significantly associated with confidence in smiling. The average smile was found in 41 (54.67%) subjects, of which 26 (63.40%) reported to be confident in smiling. The literature reports that the most attractive smiles were those with upper lip covering the central incisors around 0–2 mm20and that range may change according to level of dental education.1 The literature reports that the midline is one of the most important focal spot in an esthetic smile and that should be the starting point of a dental esthetic evaluation.21,22 However, Bhuvaneswaran9stated that discrepancies2 mm between facial and dental midline are considered esthetically acceptable. In this study, for logistic reasons, no attempt to measure this distance was made, as this characteristic was analyzed only through photographs. This kind of measurement in photographs is very difficult and many not represent the real measurement. In addition, another study showed that 1.5–2 mm discrepancies between midlines may enhance naturalness to the smile.23
The most frequent finding in teeth displayed in a smile is up to the second premolar.5,24This result is in
accordance with this study, as 84% of the evaluated subjects displayed the same amount of teeth in the second photograph (smiling photograph). The amount of teeth displayed in a smile was not statistically associated with non-confidence in smiling in this study. This finding is supported by another study that concluded that, for both orthodontists and lay people, buccal corridor measurement did not influence the esthetic evaluation of the smiling photographs.25 Another periodontal characteristic evaluated in this study was the gingival margin of lateral incisor in relation to its esthetical line. It is acceptable as an esthetic smile the gingival margin of the lateral incisors positioned 0.5– 2.0 mm below that of the central incisors and canines.26 This condition was found in 47 (62.67%) subjects in this study, which is in accordance with previous studies.27,28 These characteristics was not statistically association with confidence in smiling (p50.089). All subjects included in this study were lay persons, it is known that laypersons did not notice discrepancies4 mm in this measurements.29 However, this association should be explored by further studies in this filed, as esthetical periodontal procedures accomplishing those measurements could enhance the satisfaction with own smile.
The correlations between intraoral characteristics and self-confidence are very informative, but it is important to highlight that some psychosocial characteristics may also impact the smile perception. The literature showed that low dental self-confidence, low self-esteem and psychosocial stress are associated with negligence of oral hygiene.30–32In addition, one study showed that
subjects with malocclusion present higher scores of the Psychosocial Impact of Dental Aesthetics
However, any questions about the questionnaire were answered by the researchers during the questionnaire application. Therefore, the problems arising on the non-validation may be decreased. Furthermore, the cross-sectional study design does not allow causal relationship among the variables.
We did not ask questions about the subjects’ social economic level. However, this study was developed in a public dental university, which has dental treatment free of charge, and its patients commonly belong to the low socioeconomic levels. Hence, we can speculate that different results may be shown when including subjects with different socioeconomic levels.
Standardized photographs were used in this study and one trained examiner analyzed all the photographs. Her training was made by an experienced periodontist. All those procedures were carefully performed, and these are the strengths in this study.
CONCLUSION
In patients seeking dental treatment in a Brazilian northern public dental university, non-confidence in smiling was associated only with smiling type, at least one wrongly positioned tooth, and the desire to change at least one characteristic in the smile. It was showed that the most frequent changes in the smile mentioned by the subjects were teeth colors and their position.
Furthermore, all the statistically significant correlations found were from weak to moderate. Esthetic line of both lateral incisors presented a borderline significance and additional researches in this field should be aware of that.
DISCLOSURE STATEMENT
This study was self-funded and the authors have stated explicitly that there are no conflicts of interest in connection with this article.
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