64 PerIodoNtics INSIDE DENTISTRY—OCTOBER 2007 “The maxillary central incisors are key to inside symmetry; if they match, the observer is able to PerIodoNtics accept small irregularities in adjacent teeth.” The maxillary central incisors are key to Periodontal Plastic Surgery II: symmetry; if they match, the observer is able to accept small irregularities in adja- cent teeth. Contralateral teeth should be Esthetic Crown Lengthening equivalent in length and width on either side of the midline. In theory, the length Michael Sonick, DMD; and Debby Hwang, DMD of the maxillary central incisors should exceed that of the lateral incisors but equal that of the canines.8 The cusp tips The dramatic appeal of a face, profession establishes the following re- The analysis appraised only patients of maxillary centrals and canines also must especially caught in a smile or laugh, lies lationships and dimensions as standard, up to age 30. With time, the lips become be at the same level. The incisal edge of in the interplay between the lips, teeth, based on observational studies and ex- less everted and less elastic. In other words, the lateral incisor is 1 mm coronal to the and periodontium. Any deviation from the pert opinion. the lip line changes. Older patients show canine tip. ideal form alters perceived attractiveness, less of the maxillary teeth and more of As useful to the practitioner is the width- particularly if the change involves an Lip Line the mandibular. Fifteen-year-old sub- to-length ratio of the anterior teeth. The overexuberant gingival display. Indeed, a The position of the lip at rest and upon jects reveal 10 mm of maxillary central restoration of proper crown proportions well-known survey discovered that lay- smiling determines the amount of dental incisal length during smiling and 5 mm is a major part of esthetic dentistry. These people found a show of 3 mm to 4 mm and periodontal display. Highly incon- at rest.5 Vig and Brundo confirmed age- ratios remain more or less constant from of gingiva above the dental margin upon sistent labial movement from rest to full correlated changes and discovered that person to person; knowledge of one meas- smiling to be less esthetic than 0 mm.1,2 smile averages 7 mm to 8 mm, though it women tended to exhibit twice as much urement may be used to predict the other. Symmetry, specific anatomic positions, ranges from 2 mm to 12 mm.3 As stud- maxillary incisor length compared to men The width-to-length ratio of maxillary and harmonious proportions matter. ied by Tjan and colleagues in dental and (Table 2).6 Notice that with time, the central incisors is 0.8 mm and those of hygiene students, three smile line classifi- total level of tooth exposure at rest drops other anterior teeth lies between 0.7 and THE IDEAL ARCHITECTURE cations exist, based on the location of the from 5 mm at age 15 years to 3 mm start- 0.8 mm.9 The width and length of inci- What is normal? There are no unwaver- upper lip relative to the upper anterior ing at age 40. sors and canines were greater in men ing guidelines, but in general, the dental teeth (Table 1).4 than women, but the canine width-to- Tooth Morphology length ratio in women surpassed that of Teeth fall into one of three shapes: square, men.9 Furthermore, the mean incisors ovoid, and triangular.7 The widest of all, diameter of African-Americans exceeds a square tooth, possesses the longest prox- those of Caucasians.10 imal contact and leaves the least room in the interdental area, which creates short, Gingival Margin and Contour blunt papilla. The triangular tooth, in con- Recall that a person with an average smile trast, presents the shortest contact area line demonstrates no soft tissue above the and widest interdental space, allowing maxillary central incisors and canines. Figure 1 Ideal gingival contour. Figure 2 “Gummy smile” seen in altered pas- for a tapered and long papilla. Papillary The gingival margins of these teeth exist sive eruption. morphology mimics that of the underly- at the same level. On the other hand, the ing interproximal bone. margin of the lateral incisor falls 1 mm coronal to its adjacent counterparts.11 Table 1: Smile Line Classification In a similar vein, the heights of contour of maxillary central incisors and canines CLASSIFICATION DEFINITION PREVALENCE GENDER BIAS match and peak at the distal line angle, as they follow the curve of the cementoe- Total cervicoincisal length of the maxillary anterior teeth and namel junction (CEJ); the lateral incisor’s High 11% Female a contiguous band of gingival exposed. height of contour, alternatively, exists at the mesiodistal center (Figure 1).8 The 75% to 100% cervicoincisal length of maxillary anterior degree of this gingival scallop relies on Average 69% teeth and interproximal gingival exposed. tooth morphology as well as tissue thick- ness. A flatter contour, considered more < 75% cervicoincisal length of maxillary anterior teeth masculine, stems from thick—and thus Low 20% Male exposed. less pliable—gingiva and a square-shaped tooth. A highly scalloped margin appears Michael Sonick, DMD Debby Hwang, DMD Director Private Practice Sonick Seminars Fairfield, Connecticut Fairfield, Connecticut 66 PerIodoNtics INSIDE DENTISTRY—OCTOBER 2007 PRIMARY FACTORS that it impedes prosthetic achievement of a The four stages of passive eruption con- 1. Evaluate amount of natural-looking emergence profile.14 cern the relationship between the junc- attached gingiva • Width of attached gingival tional epithelium and the CEJ. In stage a. Enough after anticipated resection? Tooth Malposition. Orthodontic move- 1, the epithelial attachment rests on the b. Does deep pocketing exist? • Level of alveolar crest ment corrects gummy smiles caused by enamel surface. In stage 2, the attachment malpositioned teeth. In this scenario, there lies on the enamel and cemental surface 2. Evaluate level of alveolar crest. is usually an excessive display of 2 mm to apical to the CEJ. In stage 3, the junction- SECONDARY FACTORS a. More coronal than normal? 4 mm.14 Specifically, if there is a step be- al epithelium is completely on cementum. b. Any exostoses? tween the incisal and occlusal planes, a Stage 4 occurs pathologically—inflamma- • Color of gingival deep overbite exists, resulting in exces- tion causes the attachment to migrate (eg, racial pigmentation) 3. Consider restorative needs. sive gingival display.12 Here, in the pres- further apically. a. Will there be a violation of the ence of shallow probing depths, ortho- Roughly 12% of patients fail to pro- • Soft tissue thickness biologic width? dontic intrusion alone of the maxillary gress past stage 1 or 2, and they appear to b. Is there enough retentive tooth incisors moves the gingival margins api- have short clinical crowns and gingival • Bone thickness structure exposed? cally. Deep probing depths call for addi- surplus (Figure 2). This is known as al- tional gingival resection. tered passive eruption. Such patients may Figure 3 Crown-lengthening technique deter- Figure 4 Step-by-step analysis for crown- When incisor supra-eruption occurs in or may not have a high osseous crest. minants. lengthening design. response to protrusive bruxism, a gummy Boyle and coworkers measured the radi- smile with short, abraded incisors develops. ographic interproximal bone levels in a Again, treatment entails orthodontic intru- wide age range of subjects (ages 11 to sion with restoration of the incisal edges. 70).15 They saw that the distance from feminine and occurs with a thin tissue longer facial heights, shorter or hypermo- the CEJ to the osseous crest increased as and a triangular dental form.7 bile lips, maxillary anterior supra-erup- Gingival Enlargement. Inflammation (ie, patients aged and insinuated that the tion, or large alveolar processes.12,13 In an periodontal disease), hereditary gingi- crest position was not static. Coslet and CORRECTION OF ideal situation, the face may be divided vofibromatosis, and certain medications associates proposed a classification sys- THE IMPERFECT: into three equal proportions from the hair- cause enlarged gingiva. Treatment for tem for adult delayed passive eruption THE GUMMY SMILE line to the eyebrow, from the eyebrow to inflammation involves oral hygiene in- based on amount of gingiva and level In the end, objective beauty fails to exist. the base of the nose, and from the base of struction, scaling and root planing, and/or crestal bone (Table 3A and Table 3B).16 Dentists, however, should not underesti- the nose to the chin. If the lower third ap- periodontal surgery. If poor plaque con- Altered passive eruption treatment al- mate the utility of the lip–tooth–gingiva pears longer than the other segments and trol in the presence of orthodontic appli- ways involves some kind of periodontal relationships outlined above. These rules, if the maxillary lip is of regular vertical ances triggers enlargement, therapy may resection (ie, crown lengthening), at least applied broadly, help to equilibrate uneven length (18 mm to 21 mm), the patient re- include the removal of brackets and bands. of gingiva if not also of underlying bone. smiles. It is important to remark that the quires orthognathic surgery.11 Treatment of gingival overgrowth caused periodontal drape influences the shape According to Garber and Salama, bilat- by drugs (ie, anticonvulsants, immuno- Treatment Considerations of teeth. Excessive marginal or papillary eral excessive gingival display of roughly suppressants, and antihypertensives) and for the Gummy Smile soft tissue because of inflammation, al- 8 mm in a patient with coincident incisal gingivofibromatosis requires not only Elimination of a gummy smile rests on tered passive eruption, and a myriad of and posterior occlusal planes designates plaque control and dosage modifications appropriate diagnosis of its etiology.