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Studies
An overview of studies published by dentist Pieter van der Geld. He is also a reviewer for the American Journal of Orthodontics and Dentofacial Orthopedics, and the Angle Orthodontist.
Smile line assessment comparing quantitative measurement and visual estimation
Introduction: Esthetic analysis of dynamic functions such as spontaneous smiling is feasible by using digital videography and computer measurement for lip line height and tooth display. Because quantitative measurements are time-consuming, digital videography and semiquantitative (visual) estimation according to a standard categorization are more practical for regular diagnostics. Our objective in this study was to compare 2 semiquantitative methods with quantitative measurements for reliability and agreement.
Conclusions: Smile line analysis can be performed reliably with a 3-grade scale (visual) semiquantitative estimation. For a more comprehensive diagnosis, additional measuring is proposed, especially in patients with disproportional gingival display. (Am J Orthod Dentofacial Orthop 2011;139:174-80)
Download the full article, from the American Journal of Orthodontics and Dentofacial Orthopedics February 2011, Vol 139, Issue 2
- [ download ] Smile line assessment [pdf]
Age-related changes of the dental aesthetic zone at rest and during spontaneous smiling and speech
The aims of this study were to analyse lip line heights and age effects in an adult male population during spontaneous smiling, speech, and tooth display in the natural rest position and to determine whether lip line height follows a consistent pattern during these different functions.
Maxillary lip line heights during spontaneous smiling were generally higher in the premolar area than at the anterior teeth. The aesthetic zone in 75 per cent of the participants included all maxillary teeth up to the fi rst molar. Coherence in lip line heights during spontaneous smiling, speech, and tooth display in the natural rest position was confi rmed by signifi cant correlations. In older subjects, maxillary lip line heights decreased significantly in all situations. Lip line heights during spontaneous smiling were reduced by approximately 2 mm. In older participants, the mandibular lip line heights also changed signifi cantly and teeth were displayed less during spontaneous smiling. Mandibular tooth display in the rest position increased signifi cantly. Upper lip length increased signifi cantly by almost 4 mm in older subjects, whereas upper lip elevation did not change signifi cantly. The significant increasing lip coverage of the maxillary teeth indicates that the effects of age should be included in orthodontic treatment planning.
Download the full article, from the European Journal of Orthodontics 30 (2008) 366–373
- [ download ] Age related changes [pdf]
Tooth display and lip position during spontaneous and posed smiling in adults
Objective: To analyze differences in tooth display, lip-line height, and smile width between the posed smiling record, traditionally produced for orthodontic diagnosis, and the spontaneous (Duchenne) smile of joy.
Conclusions: Reduced lip-line heights, tooth display, and smile width on a posed smiling record can have implications for the diagnostics of lip-line height, smile arc, buccal corridors, and plane of occlusion. Spontaneous smiling records next to posed smiling records are therefore recommended for diagnostic purposes. Because of the dynamic nature of spontaneous smiling, it is proposed to switch to dynamic video recording of the smile.
Download the full article, from Acta Odontologica Scandinavica, 2008; 66: 207-213
- [ download ] Tooth display and lip position [pdf]
Smile Attractiveness - Self-perception and Influence on Personality
Objectives: To investigate self-perception of smile attractiveness and to determine the role of smile line and other aspects correlated with smile attractiveness and their influence on personality traits. Conclusion: The results of this research underpin the psychosocial importance and the dental significance of an attractive smile.
Download the full article, from Angle Orthodontist, Vol 77, No 5, 2007
- [ download ] Smile attractiveness [pdf]
Digital videographic measurement of tooth display and lip position in smiling and speech: Reliability and clinical application
Introduction: Tooth display and lip position in smiling and speech are important esthetic aspects in orthodontics and dentofacial surgery. The spontaneous smile and speech are considered valuable diagnostic criteria in addition to the posed social smile. A method was developed to measure tooth display in both smile types and speech.
Conclusions: This videographic method is reliable for measurement of tooth display and lip position in spontaneous and posed smiling and speaking. Application of the method is warranted especially when obtaining an emotional smile is difficult, such as cleft lip and palate or disfigured patients. (Am J Orthod Dentofacial Orthop 2007;131:301.e1-301.e8)
Download the full article, from the American Journal of Orthodontics and Dentofacial Orthopedics March 2007
