Cosmetic dentists are called upon daily to improve patients’ smiles. Yet at the heart of this request is the patient’s desire to look better and to retain a youthful appearance. The aging process of the face and the dentition creates an additional dimension of understanding when treatment planning cases where smile enhancement and facial appearance is a factor.
There is one irrefutable fact of life and that is, “We are all aging”. Some age more gracefully than others while others seem to prematurely age. What causes this disparity in the aging rate and its affect on our appearance? A more accurate assessment of aging would be to consider the difference between chronological age and biological age. Chronological age is your age measured by time. Biological age is the physical age of your body that has been influenced by other factors. Basically, biological age is an indicator of how fast we are aging. As such, the rate of aging varies from individual to individual.1 One would think that genetics would give us the best resistance against aging. Surprisingly however, genetics only accounts for 30% of the aging process. The remaining 70% is attributed to our lifestyle. Lifestyle habits such as having a balanced diet, brushing and flossing are all beneficial. Eating sweets, ice chewing, bruxing, eating lemons, smoking and drug abuse are detrimental habits that contribute to the aging effects of teeth and the appearance of the face.
There are three major factors, which can be directly related to aging dentition and the consequential aging appearance of the face; Function, Structure and Esthetics. For the purpose of this article the “Function” relates primarily to anterior teeth and anterior guidance. The “Structure” relates to structural integrity of the teeth, arches and occlusion and the “Esthetics” relates to cosmetic appearance of all the teeth and the smile. These three factors are interdependent and interrelated and rarely stand alone in function and purpose (Fig. 1).
The anterior teeth have many “functional” components. One key function involves the anterior guidance. The primary rule of the cuspids is to protect the occlusion during excursive movements. Ideally, a cuspid guided occlusion discludes the teeth and funnels the bite so that when all the teeth come into full occlusion that the vector forces are directed along the long axis of the teeth. Without cuspid guided occlusion it is more likely to have an increased rate of attrition, fremetus, recession and/or joint related issues.
Esthetically, when anterior teeth are chipped or worn down the teeth appear aged. Over time the structural integrity of these teeth become weakened. This demonstrates how the Function, Structure and Esthetics have overlapping roles (Fig. 2).
The anterior teeth also play an important role in mastication and speech. A poor bite relationship due to tooth position or bone alignment decreases the efficiency of mastication. Class III bite relationships, anterior cross bites and anterior open bites for example do not function effectively, accelerates abnormal tooth wear and alter the facial appearance. When the anterior teeth wear over time, speech alterations can become noticeable. One of the most beneficial services to curb the wear of teeth and to preserve their youthful appearance is to prescribe the use of an occlusal guard for nighttime use.
The physical structure of the teeth, occlusion, joints and periodontium are integral in maintaining the structural integrity of the dental arch and functionality of the oral processes. In the past when teeth needed restorations, the materials of choice were silver amalgam, gold and porcelain bonded restorations.
Many times additional tooth removal was also necessary purely for retentive purposes. With the advent of adhesive dentistry, more conservative methods of restoring teeth became available. Today, there are many metal free alternatives such as composite resins, porcelain inlays and onlays, porcelain veneers, all ceramic crowns and zirconium based porcelain crowns. Restoring the dentition with these new materials and upgrading aging dentistry can make teeth appear 100% natural and untreated.
Maintaining the occlusion or correcting the occlusion is key in preserving a youthful appearance. A decreased vertical dimension is one of the most common factors in dental facial related aging. This becomes very apparent in the edentulous patient. The vertical dimension can decrease due to occlusal breakdown, attrition and/or erosion.
In other cases, a deficient lower third of the face is due to a bone relationship which can create the appearance of premature aging. In these cases orthodontic treatment and orthognathic surgery may be necessary create the proper tooth position and bone relationship. These corrections not only improve the occlusion but also the facial symmetry and soft tissue profile (Figs. 3A & 3B).
A malocclusion can also contribute to temporomandibular dysfunction and a periodontal breakdown in the form of bone loss and gum recession. In correcting the occlusion with orthodontic therapy for its structural integrity, the appearance of the face and smile are both enhanced. In these cases the function, structure and esthetics are all interrelated.
Today there is a high degree of emphasis placed on cosmetic dentistry. So much so that for some dentists the Esthetics over rides the importance of function and structure. As a result, cosmetic dentistry has become subject to criticism from its own profession. With the boon in cosmetic dentistry, many practices are driven by marketing programs and advertising rather than being grounded in sound dental principles that are patient centered.2 This should be the focus of dentistry’s concern, rather than the patients desire to have natural looking teeth or a youthful, beautiful smile. Organizations like the American Academy of Cosmetic Dentistry and the Canadian Academy of Cosmetic Dentistry are dedicated to educating dentists in all these aspects of functional esthetics.
A basic tenant of cosmetic dentistry is that ALL dentistry can have an esthetic component. Esthetics should guide the case depending upon the patient’s desires but function should complete the case. Esthetics that interferes with function is likely to fail, is detrimental to the patient, creates patient dissatisfaction and gives “cosmetic dentistry” a bad reputation.
The astute dentist understands smile design and the public’s desire to improve their facial appearance. By incorporating form, function and esthetics into smile design, face generated treatment planning will guide the esthetic dentist. This will require a multidisciplined approach to treatment which includes orthodontics, oral and maxillofacial surgery, periodontal surgery, cosmetic dentistry and plastic surgery.
Developing basic beauty guidelines requires some type of regiment because when one considers the patient’s perspective; beauty becomes a measurement of an individual’s perception of beauty as noted in the adage: “Beauty is in the eye of the beholder.”
That perception of beauty may also be influenced by cultural, ethnic or racial concepts of beauty and may vary from the standards established in the North American dental community. Measurable standards must guide treatment. The “Golden Proportion” is one such measurement. Although not universally accepted, it is a good starting point to evaluate and create symmetry in the face, smile and teeth.
There should be an inherent understanding that facial beauty is based on a set of standard esthetic principles which involves the proper alignment, symmetry and proportions of the face. Basically, the shape of the face is derived from a scaffolding matrix comprised of the facial bones of the skull and jaw as well as the cartilage and soft tissues that overlay this framework (Fig. 4).
In classical terms the face height is divided into three equal thirds; from forehead to brow line, from brow line to the base of the nose and from the base of the nose to the base
of the chin. Most facial aging takes place in the lower third of the face. The width of the face is typically five “eye” widths wide3 (Fig. 5).
As anterior teeth wear with age the incisal edges flatten, chip and shorten becoming more square in appearance (Figs. 6A-C) As a result the height to width proportions of these teeth change. Typically the accepted range for the width of the central is 75% – 80% of the height4 (Fig. 7). With age the upper teeth shorten and the upper lip drops, decreasing the incisal display.
The incisal display refers to the amount of visible tooth displayed when the lips and lower jaw are in the rest position. The average incisal display of the maxillary centrals for males is 1.91 mm and the average for females is 3.40 mm.5 With age the amount of incisal display of the maxillary centrals diminishes and the amount of incisal display of the mandibular centrals increases.6 Therefore, the length of the anterior teeth and the amount of incisal display are important factors in a youthful appearance.
The shape and proportions of the maxillary anterior teeth are also important in a youthful smile. Applying the principles of the Golden Proportion to dentistry is accepted by many clinicians. This concept was first mentioned by Lombardi and later developed by Dr. Eddie Levin.7 There have been many challenges regarding reliability of this proportion due to the rigidity of this mathematical formula and the many variables among patients.
The Golden Proportion suggests an ideal mathematical proportion of 1:1.618 between the width of the laterial mesial and that of a central. When applied to dentistry it relates the apparent widths of the maxillary six anterior teeth from a frontal view. The discrepancy between the apparent width and actual width is explained by the positioning of these teeth along the curve of the maxillary arch8 (Fig. 8). Using this ratio as a guide for cosmetic treatment is a useful tool in esthetic cases to create an ideal smile (Fig. 9).
One of the earliest changes that takes place in an aging smile is the color of the teeth. Like hair color that grays with age, tooth color yellows with age. Teeth whitening is a simple procedure that helps create a youthful looking smile9 (Fig.10). According to a recent American Academy of Cosmetic Dentistry survey of dentists in North America conducted by the Levin Group, “bleaching/ whitening is the most often requested cosmetic service.”
Another sign of an aging face and smile results from the visible appearance of aging dentistry. Restorations that have outlived their usefulness, form, function and esthetics become more evident with time. Upgrading aging dentistry can create a natural and youthful appearance.
The soft tissues of the face also change with time. Anatomic changes take place early in life at 25 years of age. They include the decent of the eyebrows, nasal tip and chin vertex. Those changes accelerate abruptly at 35 years of age with gravity, laxity and thinning of the skin and changes in the lips and oral complex. The most notable changes in the lips include the architecture becoming muted, the upper lip drops, the vermillion border becomes pale, the corners of the lips droop and wrinkles appear.
To achieve an ideal smile requires analyzing and evaluating the face, lips, gingival tissues and teeth and viewing them collectively. Achieving symmetry and balance of facial and dental features makes this possible. The color, shape and position of the teeth are all part of the equation. Recognizing that form follows function and that the anterior teeth serve a vital role in the oral health of the patient is paramount.
Using a comprehensive approach to diagnosing and treatment planning of esthetic cases can help achieve the best possible smile that will enhance the overall facial appearance of the patient and provide the combined benefit of enhanced oral health (Figs. 11A-C).
Dr. Nicholas C. Davis is an Accredited member of the American Academy of Cosmetic Dentistry and is in private practice in Newport Beach, California. He can be reached at info@smilesbydavis.com.
Oral Health welcomes this original article.
REFERENCES
1.Carnes BA, Olshansky SJ. Heterogeneity and its biodemographic implications for longevity and mortality. Exp Gerontol. 2001;36:419-430.
2.Simonsen, Richard J. Dental Clinics of North America Elsevier Saunders 2007;281-287.
3.Parramn, Jos M. How to Draw Heads and Portraits. Watson-Guptill Publishing 1989; 14-15.
4.Chiche Gerard J. Pinault A., Esthetics of Anterior Fixed Prosthodontics. Quintessence Publishing Co. 1994.
5.Rufenacht, Claude R. Fundamentals of Esthetics. Quintessence Publishing Co. 1990; 73.
6.Vig RG, Brundo GC. The Kinetics of Anterior Tooth Display. Journal of Prosthetic Dentistry, 1972; 39;502.
7.Rufenacht, Claude R. Fundamentals of Esthetics. Quintessence Publishing Co. 1990; 89.
8.Blitz N, Steel C, Willhite C. Diagnosis and Treatment Evaluation in Cosmetic Dentistry -A Guide to Accreditation Criteria. American Academy of Cosmetic Dentistry. 5401 World Dairy Drive,Madison, WI 53718-3900. Pg. 16.
9.Kihn, Patricia W. Dental Clinics of North America. Elsevier Saunders 2007;328.
