A STUDY ON THE SMILE IN KOREAN YOUTH

한국 청년의 미소에 관한 연구

This study was designed to investigate the criteria of the perfect smile that was necessary to improve the esthetic problem in oral and maxillo-facial region and treating the anterior tooth region. The author took the facial straight photograph of 240 university students(male : 129, female : 111) in a resting and a smiling position, measured and analized the lip pattern and the relation between the lip and the teeth when they were smiling. Besides, 10 members of committee for appraisal (dentist : 5 persons, professor of the college of fine arts : 5 persons) estimated the smiling pattern. After that the author have compared and analyzed the obtained results. The results obtained were as follows : 1. In the shape of the upper lip, when the upper lip curved downward, it was 42.92% , straight was 45.00% and curved upward was 12.08%. The group in which the upper lip curved upward was the most esthetic. 2. In the relation between the upper lip and the teeth, high smile was 29.17%, average smile was 55.83% and low smile was 15.00%. The group of average smile was the most esthetic. 3. In the parallel relation between the lower lip and maxillary anterior incisal curvature, the group of paralled was 60.42%, the group of straight was 34.17% and the group of reverse was 5.41%. The group of parallel was the most esthetic. 4. In the relationship between maxillary anterior incisor and lower lip, the group of the maxillary anterior incisor were slightly covered by the lower lip was 10.42%, the group of the maxillary anterior teeth touched to the lower lip was 35.83%, and the no-touching was 53.75%. The group of the maxillary anterior teeth touched to the lower lip was the most esthetic. 5. In the teeth displayed in a smile, displayed to the canine was 0.84%, displayed to the first premolar was 19.17%, displayed to the second premolar was 57.92%, displayed to the first molar was 20.00% and displayed to the second molar was 2.08%. The group of displayed to the first molar was the most esthetic. 6. At smiles, the width of the mouth corner was 0.46 times of the full face width, 0.95 times of the interpupillary distance, and 1.23 times of the resting position. 7. At smiles, the lengh of the upper lip was 0.71 times and lower lip was 0.93 times of the length in the resting position.