All of my patients have one thing in common when they meet with me for the first time: they want to look better, but it has to be natural.
A natural smile is not something that we invent or create. Yes, an artist “creates” his art, whether he uses his canvas or clay, he is free to communicate whatever he wants through his compositions. While he may choose realism or avant-garde as his preferred form of communication, his goal is to precipitate an emotional response within the observer.
While smiles also induce emotions, teeth are not a canvas. They only exist because nature created them to fulfill a functional purpose. The interpretation of a human smile is a post-evolutionary development that has been refined through thousands of years of social interaction. While their social effect has become more important than their original functional purposes, teeth are yet intimately connected to oral and masticatory function.
When re-designing a human smile, a cosmetic dentist recreates nature. Sounds limited? It isn’t. Cosmetic dentistry, following a set of rules of the bio-mechanical system of the human face and chewing apparatus, has a lot of choices when integrating a bio-aesthetically harmonious smile into the human face. It is therefore still an art form. However, the recipient of the "art work" himself or herself can make a wish list and express goals for the final outcome of the masterpiece.
What smiles do we consider beautiful?
When looking at the smiles of celebrities or models in magazines and other media outlets, we will find that beautiful smiles are simply happy, youthful, and playful. Happiness is an emotional state that all of us express at moments of well-being and flourishing. Youthfulness and playfulness can be enhanced by the architecture of one’s teeth, gums, and lips. This is the field of the cosmetic dentist.
Comprehensive cosmetic dentistry understands the framework within which it can “re-create” nature. That framework is defined by the facial environment and neuro-muscular patterns, which are discussed elsewhere in this website. It suffices to say here that the basis of a natural smile is the function of the masticatory system and its relationship to facial dynamics.
Once this is understood by the cosmetic dentist, he can start communicating with the patient to establish the aesthetic goals and realistic expectations. Everybody likes youthful teeth. They are considered beautiful, yet totally conform with what nature intended them to be - functional units of chewing, incising, nibbling, smiling, and whatever social aspect you might imagine.
So, how do youthful teeth look like?
Youthful teeth are still in an unworn state.
Young teeth are not square or flat, but more intricate in nature, just as those busy and highly specialized tooth-forming cells originally created. It is quite amazing to contemplate about the fact that teeth are formed in little compartments of childhood jaws to later erupt and match perfectly to each other and within the framework of their respective faces. Cosmetic dentists should not ignore this biological and developmental reality.
Youthful teeth are whiter.
The enamel still has its full thickness and had less exposure to the pigments of foods. The enamel is thicker than in older people. The thinning of enamel (references 1 to 3) allows the yellow dentin of a tooth to permeate to the surface. Food pigements will find their way into the enamel and stick to its surface. Tooth whitening agents reduce both, internal and external dental stains.
Younger teeth have translucent incisal edges.
Older teeth have often lost their translucent incisal edges (references 4 to 9). This may simply be due to loss of enamel, which brings the dentin closer to the incisal edge. However, consumption of acidic substances reduce the proteinaceous matrix that resides along the enamel prisms (reference 12). In addition, the prolonged exposure to mineral ions and fluoride in the saliva promote the replacement of the lost matrix with minerals (reference 13), which leads to an increased density of the enamel and its permeability (reference 14).
References:
1. Atsu SS. Age-related changes in tooth enamel as measured by electron microscopy: implications for porcelain laminate veneers. J Prosthetic Dentistry 2005; 94(4): 336-341.
2. Zheng Q. Spatial distribution of the human enamel fracture toughness with aging. J Mech Behav Biomed Mater 2013; 26: 148-154.
3. He B. Mineral densities and elemental content in different layers of healthy human enamel with varying age. Arch Oral Biol. 2011; 56(10): 997-1004.
4. Hasegawa A. Color and translucency of in vivo natural central incisors. J Prosthetic Dentistry 2000; 83(4): 418-423.
5. Bayindir F. Incisal translucency of vital natural unrestored teeth: a clinical study. J Esthetic Restorative Dentistry 2012; 24(5): 335-343.
6. Stack MV. Tooth Enamel. Bristol, England, John Wright and Sons Ltd. 1965.
7. Ketterl W. Age-induced changes in the teeth and their attachment apparatus. Int Dental J 1983; 33: 262-271.
8. Brudevold F. Age changes in dental enamel. Orske Tann Tid 1957; 67: 451-458.
9. Dahlberg AA. Clinical patterns in teeth of different population groups. Symposium on Aging. Am Assoc Adv Sci 1959; 357-366.
10. Helfman PM. Aspartic acid racemization in tooth enamel from living humans. Proc Natl Acad Sci 1975; 72: 2891-2894.
11. Grahnen H. Fluoride and dental age. Acta Odontol Scand 1975; 33: 1-4.
12. Ten Cate AR. Oral Histology: Development, Structure, and Function. 12998; 5th ed.
13. Robinson C. Dental Enmel: Formation to Destruction. 1995; CRC Press, Boca Raton; p. 167.
14. Bertacci A. In vivo enamel fluid movement. Eur J Oral Sci 2007; 115: 169-173.