THE POTENTIAL FACTORS AFFECTING THE PERCEPTION OF AESTHETIC SMILE AMONG ADULT PATIENTS ATTENDING DENTAL CLINICS OF JAZAN UNIVERSITY

Uvod: Lep osmeh je važan deo izgleda svakog pacijenta, jer igra vitalnu ulogu u ličnosti, samopouzdanju i samopoštovanju osobe. Cilj: Proceniti odnos potencijalnih faktora koji utiču na percepciju lepote osmeha kod odraslih pacijenata, zadovoljstvo pacijenata sopstvenim osmehom kao i otkrivanje najčešćih faktora za nezadovoljstvo svojim osmehom. Materijali i metode: 100 muškaraca i 100 žena su procenjivali prisustvo ili nedostatak lepote sopstvenog osmeha. Kliničko ispitivanje se odnosilo na lične estetske faktore osmeha. Goldsteinov upitnik od 15 pitanja je korišćen z a p r ocenu p a cijentove s a moprocene i ličnog zadovoljstva. Prikupljeni podaci su analizirani, i smatrani statistički značajnim za p˃0,05. Rezultati: Postoji razlika u paraleli interpupilarne linije koja se poklapa sa središnjom dentalnom i središnjom linijom lica kod estetski lepog i neestetskog osmeha, kao i u simetriji maksilarnih centralnih i lateralnih sekutića i očnjaka sa njihovom aksijalnom inklinacijom (p<0.05). U pojedinim grupama pitanja detektovana je značajna razlika u odgovirima ženskih i muških ispitanika. Neka pitanja su bila blizu statističke značajnosti, dok neka pitanja nisu pokazala značajne razlike između odgovora muškaraca i žena. Zaključak: Dentalni i facijalni faktori pokazuju izuzetno značajnu vezu sa estetikom osmeha, tako da njih treba ispitivati od strane adekvatnog stomatologa kako bi se obezbedio pravilan plan lečenja u odnosu na potencijalne faktore percepcije lepote osmeha merenjem ličnog zadovoljstva pacijeata svojim osmehom.


Introduction
The word aesthetic is derived from the Greek root aisthetikos, which means the study of beauty. It is considered as a combination of art and science where art is in its form of science 1 . Dental beauty is defined as a dynamic subject which differs across different populations, regions, times, countries and even continents 2 . Different cultures express their concern about the beauty of their teeth in different ways. Ancient Asians stained their teeth with black or inlayed them with precious stones as a sign of nobility 3,4 . In the first century, Romans used to brush their teeth with urea to give them a whiter color 5 . From the 1960s -1970s, diastema was considered as a sign of beauty, while nowadays, the majority of patients want dental treatment for diastema closure 6 .
The awareness of aesthetics helps the dental practitioner to achieve an acceptable pleasing appearance. Patient's perception and knowledge about aesthetic dentistry have been markedly increased in recent years due to media exposure. Nowadays, people would like to have their teeth resemble those of their favorite actor or actress, their popular leader or politician 7,8 .
Accordingly, a clear understanding of the factors that alter the attractiveness of a smile is important in creating attractive smile. Therefore, the better understanding of the standards and norms of beauty is essential to guarantee that clinicians can create the desirable "golden smile" by applying these norms and standards to the diagnosis as well as to the aesthetic treatment plans 4 . The basic contour of the anterior maxillary teeth is the center of visual attraction. Its position gives the illusion of being the lightest and largest teeth in the mouth, thus, making them the dominant teeth in the smile 9,10 . The aesthetically pleasing smile was proposed to depend on the teeth and upper lip positions, color, size, shape, visibility of teeth and amount of part of gingiva displayed during smiling 11 . Other factors influencing dental appearance include body and self-image, personal motivation, gender and cultural differences 12,13 . Although each factor may be considered individually, all components must act together to create a final aesthetic effect 7 .
Others considered the degree of the midline shift that can affect the smile attractiveness, which differs according to the dental specialty and between dentists and their patients. Orthodontist, prosthodontics, and layperson have different perceptions of smile esthetics when evaluating maxillary incisors and gingival exposure 14,15 .
Pinho et al, in their study, found that as little as 1 mm shift is perceived by the orthodontist, a 3 mm shift is perceived by a prosthodontist, whereas layperson does not notice the midline shift when it is less than 4 mm 16 . Another important factor to be applied to smile design states that the width of the maxillary lateral incisor, as viewed from the front, should be in golden proportion to the width of the maxillary central incisor 17 . Many conflicting reports indicate that the majority of beautiful smiles did not have proportions coinciding with the golden proportion formula 7,18 . Kokich et al 19 , concluded that asymmetric alterations make teeth more unattractive to both dental professionals and the lay people. They can easily notice the change in the perception of aesthetics if the distance from gingiva to lip line is 3 mm 19 . Rodrigues et al, concluded that the reverse smile line scored the least degree of attractiveness due to deviation from aesthetic principles of unity, harmony and balance 4 . Other report that a smile with a sense of unity is considered more important and attractive than other aesthetic principles in the determination of the attractiveness of a smile 10,20,21 .
A group of local studies evaluated the perception of facial, dental, and smile aesthetics, smile attractiveness, and attitude to oral aesthetic among Saudi dentists, dental and non-dental students, lay people, and adult patients form both genders in Riyadh 3,22-24 , in Jazan 25,26 , in Jeddah 27 , in Taif 28 , and in Albaha 29 .
An ideal smile does not exist. However, the most important aesthetic objective is achieving a balanced smile, which can be described as an adequate positioning of the teeth with respect to gingival soft tissues 17,30 . Therefore, this study was conducted to assess the relationship between the potential factors affecting the perception of an aesthetic smile among adult patients attending dental clinics of Jazan University. The patients' satisfaction toward their smile and the most common factors for their dissatisfaction were evaluated.

Material and methods
The present cross-sectional study was approved from Ethics Committee at College of Dentistry, Jazan University. It was taken after a signed consent form from those patients who satisfy the inclusion criteria of this study. Inter and intra examiner calibration training sessions were performed to maximize the reliability of the study. The sample size was 200 subjects (100 male and 100 female).
The inclusive criteria were; patients should be 18-40 years-old, all teeth in the aesthetic zone are present, the teeth of the subjects are without any restoration, and no history of orthodontic treatment or maxillofacial trauma and surgery. Also, patients should have absence of the gingival recession or advanced periodontal disease, severe discoloration or hereditary defect in the aesthetic zone. Respondents were without any craniofacial anomalies. A prosthodontist evaluated the presence or absence of esthetic smile among all study subjects.
The first clinical examination sheet included three parts regarding the personal data and all aesthetic factors of the smile. The first category included interpupillary and smile lines, ideal lip line, and coincident of dental and facial midlines. The second category included gingival display during smile and incisal displays at rest (2-4 mm), incisal embrasure form, convexity of the incisal plane and Gullwing configuration. The third category was about the symmetry of maxillary central incisor (MCI), maxillary lateral incisors (MLI), maxillary canine (MC) and the axial inclination of MCI, MLI, MC. The second part was introduced as a questionnaire designed by Goldstein et al 1997, to measure the patients' self-perception and satisfaction regarding their smiles. It consisted of 15 questions 31 .
Data from the examination sheet and questionnaire were pooled for analysis. IBM Statistical Package for the Social Sciences V 20.1 (SPSS IBM, Inc., Chicago, Illinois, USA) was used for statistical analysis. Descriptive analysis included frequency and percentage were calculated for all parameters. In addition, responses of respondents from each group of parameters included (a), relationship and position of interpupillary, smile, lip lines with dental and facial midlines, (b), amount of gingival and incisal display during function, status of incisal plane, and (c), symmetry and inclination of the maxillary teeth in the aesthetic and non-aesthetic choices were analyzed.
The questionnaire designed by Goldstein et al 31 1997 was followed to evaluate the subjects and compared between the different parameters using the Chi-Square test. Statistical significance was set to the p-value of p˃ 0.05.

I -Assessment of the relationship between the potential factors affecting the perception of aesthetic smile
The presence of parallelism between interpupillary line and one or both of anterior Incisal plane and maxillary anterior gingival margin was 81.6% among the cases with aesthetic smile and 61.9% among cases with non-aesthetic smile. The p-value was highly significant P < .002. The smile line was presented 'Parallel with inner curvature of lower lip in was 91.3% of cases with aesthetic smile and 87.6% in cases with nonaesthetic smile. The p-value was not significant p ˂0.402.
The percentages of aesthetic and nonaesthetic smile cases of coincided dental and facial midlines were recorded in 80.6% and 61.9% among cases with aesthetic and nonaesthetic smile respectively. In addition, it was extremely high in the "'Coincided of dental and facial midlines'' parameter and presented in 90.3% and 82.5% cases among the aesthetic and non-aesthetic choices, respectively (Table 1). Table 2, showed the number and percentage of the gingival display during smile (1-2mm.) were extremely high and represented in 87.4%, and 82.5% cases, also the incisal display at rest (2-4 mm) was quite high and registered in 86.4%, and 81.4% cases in the aesthetic and non-aesthetic choices, respectively. The frequency and percentage of the incisal embrasure form and convexity of the incisal plane were recorded as 90.3% and 86.6%, in the esthetic and nonaesthetic choices, but convexity of the incisal plane was 91.3% and 71.1% for the aesthetic and non-aesthetic choices, respectively. Finally, the gull-wing configurations were founded in less number and frequency 65% among the aesthetic and 41.2% in the nonaesthetic zone. All the variable p-values were non-significant p < 0.05. Table 3 shows the relation of the maxillary anterior teeth in relation to their symmetry and axial inclinations.

II -Evaluation of the patient's satisfaction toward their smile and the most common factors for their dissatisfaction
Analysis of the results of the questionnaire answered by the subjects participating in the present study showed great variation. Some questions showed a highly significant difference in the answers whereas others showed a low significant difference, yet more questions showed no statistically significant differences between the answers. Of the questions with the highest significant difference is the question about "Do you look at magazines and wish you had a smile as pretty as the models?" where most of the female subjects answered yes 79% and only 21% answered No. The second question was "When you read a fashion magazine, are your eyes drawn to the model's smile?" with 83% female having the answer Yes; and only 17% scored NO. Male subjects results show the highest percentages when asked "if they think that their teeth are too long or too short, too wide or too narrow'', 17% scored Yes; and 15 % scored No; 83% and 85%, respectively. The pvalues were 0.000. Questions with a low level of significant differences; 77% of males and 90% of females subjects in this study answered Yes when asked "Is there someone you believe has a better smile than you? " or "Do you wish your teeth were whiter?" with p-value equal to 0.011 and 0.001, respectively. In addition, the percentage of both male and female subjects in relation to the answer No for the question "Are your teeth too square or too round''? were 87% and 71%, respectively, with pvalue equal to 0.008. All the remaining questions (7,12,10,3) were near to the significant differences, while questions (1,2,9,11) showed no significant differences between males and females with p values equal to or less than 0.05 (Table 4).

Discussion
Since the early years of history, humans have been looking for what they consider as the perfect smile. The issues of the aesthetic smile are influenced by many cultural, educational and socioeconomic factors. In recent years, the media has put great stress in the importance of having a beautiful aesthetic smile and movie stars have become the role models for an aesthetic smile 32,33 .

Assessment of the relationship between the potential factors affecting the perception of aesthetic smile
An essential and vital question does exist, that is who should be the judge of dental aesthetics, the clinician or the patient when their views diverge frequently 34,35 . So patients and dentists together, as well as dental technicians, should be involved during any aesthetic work.
The current study was designed to comprehensively examine the potential factor which might play a role in projecting and influencing the so-called aesthetic smile. A total of 16 factors were divided into three categories to investigate the patients' perception, and then the results were subjected to both descriptive and analytical analysis. A significant difference was recorded in the current study in the first category from the first part which included, coincided of dental midlines and symmetry of maxillary teeth, there were the same findings in a study carried by Alhammadi et al 26 , including male and female subjects in their study. In addition, our finding was near and on the border to the finding recorded by Aamassi et al 24 and Mokhtar et al 27 in a study examining 130 dentists and final year dental students. However, a low significant difference was detected when examining the coincidence of dental facial midlines in both aesthetic and non-aesthetic smiles. The rest of the factors showed no significant difference (the smile line, maxillary lip line, gingival display, incisal display, incisal embrasure form and axial inclination of the maxillary canine). These results are in contrast to those reported earlier by Vander et al 11 , who stressed the importance of the maxillary lip line and incisal display. In our study, the level of satisfaction was high in term of gingival display, crown width and length, and the number of teeth showed during smiling in both aesthetic and non-aesthetic area. This finding was in contrast with the finding of Alharthi et al 28 , which could be explained by his selected groups which were from medical fields, and dental students. These groups of subjects are always concerned about their look. Also, our findings agreed with the results mentioned by Talic et al 22 in relation to the categories of the second parts which involved the amount of gingival displays during smile (1-2mm) and during rest (2-4mm), as well as incisal embrasure forms. All parameters were not significant in both research studies(p˃0.077 and p˃0.367.
Na osnovu rezultata ove studije jasno je da su registrovani procenti neznatno veći od rezultata koje su spomenuli Alharthi i sar. 28 , u studiji izvedenoj među studentima univerzitetskih medicinskih fakulteta na Univerzitetu Taif. Međutim, rezultati ove studije u vezi sa pitanjima koja su bila blizu značajne razlike (pitanje br. 3: In the current study, the third category of the first part which involved the variables which showed the highest statistically significant difference between subjects with aesthetic smile against those with nonaesthetic smile included the symmetry of MCI, MLI and MC where p< 0.000 (Table  3). Similar results were reported in studies by Talic et al, Rosenstiel et al, and Goncalges et al 22,36,37 .

Patients'satisfaction with their smile and the most common factors for their dissatisfaction
Variation in the size of the teeth and their relation to the face may affect the aesthetic appearance. Therefore, the teeth must be in proportion to one another and be in proportion to the size and shape of the face to achieve an aesthetically pleasant smile 11,36 . The need for understanding patients' opinion regarding their aesthetics might improve the communication between dentist and patients during dental treatment which may have a positive effect on the aesthetic outcome 38 . In the second part of the study comprising the patients' satisfaction for their smile (Table 4), the question with highest significant difference was the question about "Do you look at magazines and wish you had a smile as pretty as the models?" having p-value 0.000. In the question "When you read a fashion magazine, are your eyes drawn to the model's smile?" 83% female scored Yes; and only 17% scored NO. Similar findings were recorded by Silva et al 39 , who conducted a cross-sectional observational study among undergraduate dental students in Brazil. This study was aimed to verify the aesthetic self-perception regarding their smiles. In general, our result was in agreement with their findings in that, females were more dissatisfied about their own smiles than males. The results of the current study coincided with their results regarding highly significant differences in question number 5 '' Do you look at magazines and wish you had a smile as pretty as the models? and question number 6 ''When you read a fashion magazine, are your eyes drawn to the model's smile? However, our finding was not in agreement with their finding in the question number 3'' Do you photograph better from one side of your face?, which can be explained by the fact that self-awareness among females is always higher than male. In addition, our findings were parallel to their recorded results in the questions with non-significant difference 1,2,9,11, and in questions which were near to the significant (3,7,10,12).  "Da li na fotografiji bolje izgledate slikani s jedne strane lica?", pitanje br. 7: "Kada se osmehnete i pogledate u ogledalo, da li vidite nedostatke na vašim zubima ili desnima?" i pitanje br. 9: "Da li ste zadovoljni izgledom vaših desni?" (p<0.079, p<0.045, p<0.049), su u potpunoj suprotnosti sa njihovim rezultatima (p<0.037, p<0.0001, p<0.008) koje su bile veće od njihovih p vrednosti za ista pitanja bez signifikantne razlike. Sva pitanja koja se odnose na oblik, veličinu i dužinu zuba ili izgled desni tokom osmeha (pitanja od broja 12 do broja 15) pokazala su podudarne rezultate sa rezultatima ovog istraživanja, ali nisu bili podudarni sa rezultatima koje su zabeležili Silva i sar. 39 . To bi moglo biti zbog njihovih ispitanika koji su studenti.
From our results, it is clear that the registered percentages were slightly higher than the results mentioned by Alharthi et al 28 , in a study among university medical colleges students at Taif University. However, we totally disagree with their results in relation to questions that were near to the significant difference (Question # 3 "Do you photograph better from one side of your face'', Question # 7 " When you look at your smile in the mirror, do you see any defects. difference which were questions numbers (3,7,10,12). in your teeth or gums? and Question # 9 " Are you satisfied with the way your gums look? with p values 0.079, 0.045, 0.049, respectively which were higher than their p values for the same questions 0.037, 0.0001, 0.008 in non-significant questions. All questions related to the shape, size and length of teeth or appearance of gum during smiling (Questions from # 12 to 15) showed coinciding results with the results in our research, but were not parallel to the results recorded by Silva et al 39 . This might be due to their subjects who were all university students.
Overall our recorded results agreed with the results mentioned by Al Moaleem et al 25, , Maghaireh et al 40 , but disagreed with Alghamdi ASA 29 , those reported that majority of the dental patients in Albaha city were dissatisfied with their dental appearance, which may be related to the elder age of the dissatisfied examined patients.

Conclusion
Based on results of the present study it could be concluded that dental and facial factors which showed high significance relationship with aesthetic smile should be observed by prosthodontists, orthodontists and laboratory technicians to provide a proper treatment plan in respect of the potential factors of the aesthetics smile perception with the help of self-satisfaction measurement.