J Korean Acad Prosthodont.  2012 Oct;50(4):249-257. 10.4047/jkap.2012.50.4.249.

A study on the smile according to age and esthetic evaluation by the degree of dental knowledge

• Kim SJ
• Kim MG
• Park SM
• Ban JS
• Park SW

• KMID: 2195466
• DOI: http://doi.org/10.4047/jkap.2012.50.4.249

Abstract

PURPOSE
This study was designed to help to provide the criteria of the esthetic smile in oromaxillary region on twenties, fifties and sixties.
MATERIALS AND METHODS
The facial straight photographs of 33 adults (male 15, female 18, mean age 27.2 years old) and 20 seniors (male 7, female 13, mean age 55.6 years old) in resting and smile position were taken. The measurements and proportion of lip-teeth relation during smile were statistically analyzed, and survey of freshmen and seniors who belong to School of Dentistry, Chonnam National University were taken to select the best esthetic smile among the photographs.
RESULTS
In the relationship between the upper lip and the teeth, average smile was the most frequent, and mean of smile line ratio was 1.090 in young group and 0.90 in old group. The correlation between the buccal corridor ratio and exposed teeth count was inversed. At smile, most frequently exposed tooth was the second premolar (63.64%) in young gourp and the first premolar (35.00%) in old group. The correlation between the upper lip change ratio and exposed clinical crown length of maxillary central incisor was inverse, but there was no correlation between the lower lip change ratio and exposed clinical crown length of maxillarycentral incisor.
CONCLUSION
In the result of survey, the students selected the case exposed to the first premolar as the most esthetic smile. The most esthetic smile between full facial photograph and the lip only photograph by the freshmen was different, but that by seniors was identical.

Keyword

Smile; Esthetic; Anterior teeth; Survey

MeSH Terms

Adult
Bicuspid
Crowns
Dentistry
Female
Humans
Incisor
Lip
Tooth

Figure

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  Fig. 1 Sample pictures taken at A: resting state, B: smile.

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  Fig. 2 Landmarks used to evaluate the patterns of the smile.

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  Fig. 3 Pictures for the questionnaire (A: Mouth, B: Face).

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