This document discusses concepts and principles for analyzing smiles and designing esthetic dental treatments. It begins with defining the differences between cosmetic and esthetic dentistry, emphasizing a natural appearance. The process of smile design and analysis is described as involving 5 elements: 1) facial analysis, 2) dento-facial analysis, 3) dento-labial analysis, 4) dental analysis, and 5) an evaluation of the specific dental elements. These elements are interrelated and changing one impacts the others. Key aspects of smile design analyzed in more detail include the dental midline relationship to the face, incisal edge position, incisal display during smiling, the smile line, and the buccal corridor

1. EsTHetics
44 INSIDE DENTISTRY—JULY/AUGUST 2009
“...it is critical to understand
inside
EsTHetics
the esthetics is not a finite point; in fact,
esthetics can be a broad zone.”
Smile Analysis and Esthetic Design:
“In the Zone”
Edward A. McLaren, DDS, MDC; and Phong Tran Cao, DDS
Increasingly, patients seeking treat- ment should be an enhanced but natural of the teeth to the lips), (4) dento-gingival
ment present with the primary concern appearance that imparts a vibrant and analysis (the relationship of the teeth to
of an esthetic enhancement to their oral believable appearance to the patient. This the gingiva, and (5) dental analysis (the
condition. Many articles have been should be our goal in dental esthetics: a intertooth and intratooth relationships,
written and courses taught over the result that would be considered “bright, ie, form and position along with color).
years on concepts of smile design to beautiful, but believable.” This may entail Even though there is a specific sequence
develop a treatment plan to get an the use of cosmetic procedures as already recommended it must be understood
esthetic outcome for the patient.1-7 stated but, just as importantly, it blends that all of the elements are interrelated;
Esthetic or cosmetic dentistry has the functional and biologic requirements changing one will have an impact on all
become one of the main areas of dental of the patient into a durable and long- the others.
practice emphasis and growth for sever- lasting result. The treatment should be as The concept of the evaluation sequence Figure 1 Image of smile where the facial and
al years. These terms (ie, esthetic and conservative as possible and allow the pa- is based starting with a macro view of the dental midline do not line up.
cosmetic) have almost become syn- tient future options as new technologies patient and progressively working down
onymous in our dental nomenclature. are developed. to a micro view, ie, looking at the face
The literal definitions of these terms are This article will focus on historically first and then progressing to evaluate the form and balance that can be affected by
very different. Cosmetic means to do accepted smile design concepts and pres- individual teeth last. The recommended dental treatment. Regardless of how at-
“something superficial to cover a defect ent research of smile parameters that will sequence does not necessarily imply the tractive the teeth appear, if they do not
or deficiency” and secondarily “serving to help the reader to design their esthetic order of importance (even though macro relate to the facial structures spatially, the
beautify the body.” The second part of treatments. It is very important to note view esthetics is noticed by observers be- result will be unesthetic. Because of the
this definition has a very large cultural that smile design concepts have been pre- fore micro views); it is just a way to sys- space limitations of this article, the top-
component to this, ie, beauty is in the sented in a very static manner, ie, specif- tematically evaluate a patient. And the ics of facial analysis and dento-facial ana-
eye of the beholder. There is also an ic measurements for form, color, and po- very last thing planned is what material lysis (other than the topic of midline)
implication that something “cosmetic,” sition of esthetic dental elements. This is should be used consistent with satisfying will not be covered. The reader is referred
while deemed “beautiful,” is obvious to fine for basic information transfer of smile all treatment planning goals. The treat- to many references on facial analysis and
the observer that a facial or dental char- design principles, but it is critical to un- ment sequence may change and follow its impact on smile design and treat-
acteristic has been en- derstand the esthetics is not a finite point; an entirely different course depending ment. 2-12 Suffice it to say that obvious
hanced—eg, using make-up to accentu- in fact, esthetics can be a broad zone. We on these variables. If the treatment plan facial abnormalities, especially when ob-
ate a facial feature. According to the like to refer to this as “the esthetic zone” for follows a proper sequence, a restoration serving the lower one third of the face,
Merriam-Webster dictionary, the defi- a given patient. Thus, we will give from our would not be planned for a tooth that is should be referred for orthodontic and
nition of esthetics, on the other hand, is evaluations what we believe are zones or malpositioned to the point that it would orthognathic consultation.
“responsive to or appreciative of what “ranges” of esthetic values for smile design. require mutilation to reposition it restor-
is pleasurable to the senses” or “pleasing atively. The treatment plan would repo- Midline
in appearance.” Thus, cosmetics and THE PROCESS OF SMILE sition it initially so that the tooth is not Ideally, the dental midline should end up
esthetics are somewhat inseparably DESIGN AND ANALYSIS structurally compromised with excessive collinear with the facial midline but usu-
intertwined, but esthetics also encom- Smile design should involve the evalua- preparation. ally it does not (Figure 1). Fortunately, in
passes appearances that do not have a tion of certain elements in a specific se- our experience of all the esthetic parame-
“cosmetic appearance.” quence; (1) facial analysis (general facial FACIAL AND ters, dental midline abnormalities are the
Timeless human esthetics implies a balance), (2) dento-facial analysis (maxillo- DENTO-FACIAL ANALYSIS least noticed by patients and dental per-
sense of beauty, a pleasing impulse, natu- mandibular relationships to the face, and The smile analysis evaluation should be- sonnel. In one study by Kokich,13 it was
ralness, and a youthful appearance relative the dental midline relationship to the face) gin with the observation of the facial ele- shown that the public could not tell that
to one’s age. The goal for esthetic treat- (3) dento-labial analysis (the relationship ments.1-11 There are guidelines to facial dental midlines were off facial midlines
of up to 4 mm. As long as the midline is
parallel with the long axis of the face,
Edward A. McLaren, DDS, MDC Phong Tran Cao, DDS midline discrepancies of up to 4 mm will
Founder and Director Senior Resident generally not be perceived as unesthetic.
UCLA Center for Esthetic Dentistry Residency Program UCLA Center for Esthetic Dentistry Slight corrections of midlines can be ac-
complished with restorative dentistry as
Founder and Director long as the maxillary centrals are made
UCLA Master Dental Ceramist Program relatively symmetric and correct inter-
Private Practice limited to Prosthodontics and Esthetic Dentistry tooth relationships are maintained. If the
individual teeth do not require restora-
tion and there is a large midline discrep-
ancy, the ideal treatment is orthodontics.

2. EsTHetics
46 INSIDE DENTISTRY—JULY/AUGUST 2009
Figure 2 Image of the lower one third showing Figure 3 Lower one third smiling image showing Figure 4 Image showing the smile line with a Figure 5 Image showing excessive (too much
tooth display at rest. The display was measured the relationship of the incisal edge to the lower gull-wing effect. negative space) buccal corridor problem, which
to be between 2.5 to 3 mm. lip during smiling. can be related to a narrow arch form.
DENTO-LABIAL ANALYSIS lent smile were measured for an average lengthening alone; this case should be tions to this pattern can be effectively
The next step in the esthetic analysis is to of 7 mm to 8 mm of lip movement. Also referred for orthognathic surgical correc- treated with esthetic recontouring or con-
evaluate the relationship of the lips to the during smiling, all of the maxillary ante- tion. In clinical situations where there is servative restorative dentistry. In situa-
teeth, ie, visual tooth display both stati- rior teeth are displayed, from incisal edge normal tooth display at rest, correct tooth tions where there is ideal tooth form and
cally and dynamically, then buccal corri- to gingival margin (Figure 2 and Figure length, correct relationship of the teeth to color but there are discrepancies to the
dor (which is related to arch form). 3). Most of the maxillary premolars and the lower lip when smiling, and excessive smile line or visual tooth display, restora-
sometimes the first molar are displayed gingival display during smiling, this is usu- tive dentistry is not indicated, as this would
Incisal Edge Position when smiling. In a study by Kokich,13 it ally indicative of excessive lip mobility. cause unnecessary mutilation of other-
Published reports have shown that the was demonstrated that dental evaluators This is a very difficult situation to treat, as wise healthy tooth structure. In these clin-
average 30-year-old woman displays about and lay people still considered it esthetic almost any treatment will leave an esthetic ical situations, and when there is moder-
3.5 mm of maxillary central incisor tooth if 2 mm of gingiva showed in a full smile. compromise in either a static or dynamic ate to severe distortion of the smile line,
structure when the lips are at rest (Fig- In our opinion, it is still in the “esthetic lip position. orthodontics would be the more appro-
ure 2).11,14,15 The prosthodontic litera- zone” to show up to 3 mm of gingiva in a priate treatment.
ture has generally recommended setting full smile, especially if there is slightly Smile Line
denture teeth so that 2 mm of tooth struc- more than 8 mm in lip movement during In an esthetic smile, the edges of the max- Buccal Corridor
ture is displayed at rest. 14,16 In the au- a smile (Figure 1). illary anterior teeth follow a convex or In an esthetic smile there is what has been
thor’s experience, the 2 mm exposed at If the incisal display at rest is 3 mm to gull-wing course matching the curvature termed negative space, which is a small
rest is generally less than desired by es- 4 mm, and it is determined that the teeth of the lower lip (Figure 4), and are gener- space between the maxillary posterior teeth
thetically driven patients. Also, in the au- are too short, then surgical crown-length- ally radially parallel to the horizon. From and the inside of the cheek. A broad smile
thors’ experience, for most patients who ening procedures should be considered. a frontal view, the maxillary arch from with a minimal buccal corridor is deemed
have improved esthetics as their primary Two main considerations for surgical central to molar appears to curve upward, most esthetic by lay people;19 however, a
treatment goal, between 3 mm and 4 mm crown lengthening are dentin exposure but not always. If it does, this apparent broad smile without a buccal corridor could
displayed at rest will be esthetically ideal. and crown-to-root ratio. The goal is to curve may be a result of a slight posterior also be perceived as fake.20 If the space
Another guide for evaluating the esthetic never expose root structure (dentin) pure- cant to the maxilla or the frequent ap- appears excessive (Figure 5) when the pa-
position of the maxillary anterior incisal ly for esthetic reasons, especially if bonded pearance of the Curve of Spee in the in- tient is smiling, a small amount of the
edges applies when the patient smiles; in porcelain is the ideal restorative option tact dentition. Slight to moderate devia- space can be filled by increasing the buccal
an esthetic composition, the tips of the for the patient. If the gingival margin
maxillary anterior teeth come very close needs to be apically placed for esthetics,
to touch the lower lip up to a maximum and crown lengthening would expose den-
of 3 mm away (Figure 3). tin, the ideal option would be to ortho-
The esthetic treatment would be to re- dontically or orthognathically move the
position the incisal edges of the maxillary teeth with the dento-gingival complex
anterior teeth within these two dento- applicably to satisfy esthetic requirements.
labial esthetic zones. The modality of treat- The other obvious consideration is crown-
ment would be determined in conjunc- to-root ratio. As a guideline, the primary
tion with the evaluation of all the other author will not crown length more than
smile design and treatment goal parame- what would create a 60:40 crown-to-root Figure 6 Image of a smile that was rated Figure 7 Image showing the gingival line on
ters. If patients display less than 4 mm of ratio. This option is only considered if gin- excellent by several evaluators at the UCLA the same patient. Note the lateral and central
the maxillary central at rest and the teeth gival dentin is already exposed and crown Center for Esthetic Dentistry. apical position of the gingival margin is on a
need to be lengthened, the length will lengthening is needed to be done anyway straight line that is completely horizontal.
generally be achieved by adding to the for biologic and structural reasons.
incisal edge. If there is insufficient tooth display at
rest, normal lip mobility, the teeth are the
Incisal Display During Smiling correct length, and there is inadequate
Tooth size and position, lip length, and tooth display during smiling, then this is
lip mobility greatly affect maxillary tooth diagnostic of vertical maxillary insuffi-
display both statically and dynamically. ciency. This is not a case that should be
The average lip length has been measured treated with esthetic tooth lengthening.
at between 20 mm to 24 mm measured This is an orthognathic problem and
from the base of the nose to the edge of should be referred for proper treatment.
the upper lip.1,8 Average lip mobility in a Conversely, if there is too much tooth dis-
normal esthetic smile is 7 mm to 8 mm as play at rest, normal lip mobility, normal Figure 8 Image demonstrating the measure- Figure 9 Image showing close to an 80% width-
measured in the UCLA Center for Es- tooth length, and an excessive display of ments of the ideal gingival scallop, with the to-length ratio and optical width of the central rel-
thetic Dentistry (CED) study by showing gingival during smiling (more than 3 mm) percentages showing the papilla length relative ative to the lateral and the lateral relative to the
evaluators images of patients’ lower one this is diagnostic of vertical maxillary to tooth length. canine. Note that esthetic percentages do not fol-
third of their face while smiling. Subjects excess.15,17,18 This should not be treated low the golden proportion, especially the canine.
who were rated to have a good to excel- by restorative dentistry and surgical crown

3. EsTHetics
48 INSIDE DENTISTRY—JULY/AUGUST 2009
ciples. Prac Periodont Aesthet Dent. 1998;
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6. Spear F. Facially generated treatment plan-
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cial and dentofacial analysis. J Calif Dent
Assoc. 2002; 30(11): 839-846.
8. Arnett GW, Bergman RT. Facial keys to ortho-
Figure 10 Preoperative image of a case requiring Figure 11 Preparations of the same case which Figure 12 Postoperative image of creating ideal
dontic diagnosis and treatment planning,
improving esthetic proportions. shows the significantly pegged lateral that was proportions using bonded porcelain restorations.
Part II. Am J. Ortho Dent Facial Orthop. 1993;
present under the old composite bonding.
103(5):295-411.
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contours of the maxillary posterior restor- the free gingival margin to the tip of the Intertooth Relationships and science of facial esthetics. Semin Or-
ations—assuming restorations need to be papilla is about 40% to 50% of the length When a person smiles and the teeth are dis- thod. 1995; 1(2):105-126.
placed for restorative reasons. If con- of the maxillary anterior tooth and fully played, there is an intertooth relationship 10. Morley J, Eubank J. Macroesthetic elements
servative additive or subtractive (ie, es- fills the gingival embrasure (Figure 8).22 that needs to be maintained for the compo- of smile design. J Am Dent Assoc. 2001;
thetic contouring) techniques will not In situations where this condition does sition to be considered esthetic. The maxil- 132;39-45.
work esthetically, then orthodontics not exist, periodontal and orthodontic lary central incisors should be relatively but 11. Chiche G, Pinault A. Artistic and scientific
should be considered. procedures are the treatments of choice to not perfectly symmetrical. They should principals applied to esthetic dentistry. In:
create the correct gingival architecture. dominate but not overwhelm the smile.11,21 Chiche G, Pinault A. Esthetics of Anterior
DENTO-GINGIVAL ANALYSIS Orthodontics not only positions the teeth This is obviously very subjective, but re- Fixed Prosthodontics. Quintessence Publish-
The lips frame the teeth and gingiva. The but also can reposition gingiva and bone. search has shown that in smiles determined ing 1994:13-32.
gingiva frames the teeth. The ratio of tooth Gingival color should appear pink and to be esthetic, there was a clear dominance 12. Peck S, Peck L. Esthetics and the treatment
structure to the amount of gingival and healthy or consistent with the healthy col- of the maxillary central incisor. Many au- of facial form. Craniofacial Growth Series.
labial tissue should be harmonized to or of individual race variations. thors recommend using the golden propor- McNamara JA, ed; Vol. 28 Ann Arbor, MI;
prevent an over-dominance of any one tion to define the optical width of the max- University of Michigan; 1992:97.
element. As such, establishing proper gin- DENTAL ANALYSIS: illary teeth as they go posteriorly.21,25,26 13. Kokich VO, Kiyak HA, Shapiro PA, Comparing
gival relationships relative to the lips has INTRATOOTH AND One study has demonstrated that the actu- the perception of dentists and lay people to
been discussed in the previous section. INTERTOOTH RELATIONSHIPS al measurements of most people’s anterior altered dental esthetics. J Esthet Dent. 1999;
Gingival margin placement is based on teeth do not in fact follow the golden pro- 11:311-324.
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cussed in the next section). Other factors incisors has been measured at between 10 the golden proportion that this be consid- 504.
to consider in designing esthetic gingival mm to 11 mm.11,12,23 In a recent study by ered more esthetic than other arrange- 15. Connor AM, Moshiri F. Orthognathic surgery
relationships are: gingival line (the rela- Magne,24 the average maxillary length of ments. In the authors’ experience, the re- norms for American black patients. Am J Or-
tionships of free gingival margins of the a unworn maxillary central to the cemento- lationship of the maxillary lateral to central thod. 1985;87(2):119-134.
maxillary teeth), gingival scalloping and enamel junction was slightly over 11 mm. incisor comes very close to the golden pro- 16. Frush JO, Fisher RD. The dysesthetic inter-
contour, papillary tip positioning, and Patients who seek esthetics as a primary portion in an esthetic smile, and can be pretation of the dentogenic concept. J Prosthet
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Gingival Line From measuring esthetic outcomes on eral incisor about 65% of the central incisor ment of excessive gingival display. Pract Peri-
There have been several gingival refer- hundreds of personal patients and hun- (or a little less than two thirds). The authors odontics Aesthet Dent. 1999;2:265-272.
ence line relationships that exist from dreds of resident patients in the UCLA have found that the canine does not follow 18. Schendel SA, Eisenfeld J, Bell WH, et al. The
maxillary bicuspid to the contralateral CED, the authors have determined the the golden proportion optically and is gen- long face syndrome: vertical maxillary excess.
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the horizon and relatively symmetric on 70% to 80%.11,22 In measuring smiles in postoperative examples with esthetic para- 98-111.
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