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  • 2. 375Maxillary Anterior Papilla DisplayDuring Smiling: A Clinical Study of theInterdental Smile LineMark N. Hochman, DDS* The smile has become the objec-Stephen J. Chu, DMD, MSD, CDT** tive endpoint evaluation by whichDennis P. Tarnow, DDS*** practitioners define esthetic treat- ment outcomes. Esthetics embrac- es and encompasses all specialtiesThe purpose of this research was to quantify the visual display (presence) or of dentistry; therefore, proper di-lack of display (absence) of interdental papillae during maximum smiling in a agnosis of a patient’s esthetic smilepatient population aged 10 to 89 years. Four hundred twenty digital single-lens line before any treatment is under-reflex photographs of patients were taken and examined for the visual display taken is critical for success.of interdental papillae between the maxillary anterior teeth during maximum Previous studies on the smilesmiling. Three digital photographs were taken per patient from the frontal, right line have focused on the visualfrontal-lateral, and left frontal-lateral views. The data set of photographs was amount and location of midfacialexamined by two examiners for the presence or absence of the visual display tooth and gingival display relativeof papillae. The visual display of interdental papillae during maximum smiling to the upper lip.1–4 Tjan et al setoccurred in 380 of the 420 patients examined in this study, equivalent to a 91% smile guideline standards in theoccurrence rate. Eighty-seven percent of all patients categorized as having a profession in the mid-1980s.2 Theirlow gingival smile line (n = 303) were found to display the interdental papillae research classified smiles into threeupon smiling. Differences were noted for individual age groups according tothe decade of life as well as a trend toward decreasing papillary display with basic categories (high, average,increasing age. The importance of interdental papillae display during dynamic and low) according to the exposuresmiling should not be left undiagnosed since it is visible in over 91% of older of the midfacial cervical margin ofpatients and in 87% of patients with a low gingival smile line, representing a the clinical crown relative to the ver-common and important esthetic element that needs to be assessed during smile milion border of the upper lip. Theanalysis of the patient. (Int J Periodontics Restorative Dent 2012;32:375–383.) majority of these patients (69%) fell within the category of the average   * linical Associate Professor, Department of Orthodontics and Department of C smile line, with 75% to 100% tooth Periodontology, New York University College of Dentistry, New York, New York.  ** linical Associate Professor and Director of Esthetic Dentistry, Columbia University C exposure (Fig 1). A total of 11% of College of Dental Medicine, New York, New York. subjects were found to reveal the*** linical Professor and Director of Implant Education, Columbia University College of C entire clinical crown with a contigu- Dental Medicine, New York, New York. ous band of gingiva, hence catego- Correspondence to: Mark N. Hochman, 150 East 58th Street, Suite 3200, New York, NY rized as a high smile line (Fig 2). 10155; fax: 815-572-9374; email: The low smile line category, found Volume 32, Number 4, 2012 © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 3. 376Fig 1    Average smile line where 75% to Fig 2    High smile line where 100% tooth Fig 3    Low smile line where 75% tooth100% tooth exposure is displayed. exposure plus some of the midfacial gingiva exposure or less is displayed. is 20% of patients, represented a using videography.3 The amount of approach to the comprehensivesmile displaying less than 75% of midfacial tooth display could have analysis of tooth form and its sur-the clinical crown (Fig 3). been underestimated by previous rounding gingival structures. This A limited patient population studies since posed or static pho- biometric approach uses determi-between 20 to 30 years of age from tographs have been shown to limit nants that are identified and canboth sexes was used in one such the display of maxillary anterior be measured objectively, allowingstudy.2 Additionally, each subject teeth during smiling. Of importance the clinician to more easily identifywas analyzed from a single frontal was the finding of a correlation tooth and gingival abnormalitiesfull-face posed photograph per- between natural aging and the re- for the dentate patient. The clinicalspective. Gender differences were lationship between the soft tissue endpoint of treatment enables indi-found for women versus men, who and dentition by Dickens et al.6 It vidual patient analysis to be quanti-demonstrated greater tooth dis- was found that increased age re- fied in relation to normative valuesplay during smiling, respectively.2,5 sults in a significant reduction of the that have been reported and con-Of note, differentiation of smile cat- exposed clinical crown to the bor- firmed by different research groupsegories was primarily based on the der of the upper lip during smiling using various methods.10–12 Severalrelative position of the vermilion of age groups evaluated between groups have established that ob-border of the upper lip to the total the ages of 7 and 40 years; how- jective measurements of width-to-clinical crown length. The relative ever, only subjects younger than 40 length ratio of teeth or proportionposition of the upper lip to the in- were evaluated in this study.6 result in a mean 80% of patientsterdental papillae was not assessed Chu et al7,8 and Stappert et being judged to have pleasingindependently for these groups.2–4 al 9 recently published a series of dimensions for maxillary ante- More recently, Van Der Geld studies in an attempt to more ob- rior teeth.13–15 In addition, recentlyet al demonstrated that patients jectively diagnosis and treat the published data demonstrate thatreveal more tooth display during needs of the esthetic-restorative the interdental papilla proportionspontaneous versus posed smiling patient. They took a ”biometric” (clinical tooth length to interdentalThe International Journal of Periodontics & Restorative Dentistry © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 4. 377Fig 4    Height of the interdental papillae measured from the gingi-val zenith incisally is roughly 40% of the length of the clinical crown.papilla length) can be measured papillary gingival tissues. It is be-objectively in patients with estheti- lieved that the visual display (pres-cally pleasing smiles. This papilla ence) or lack of display (absence) ofproportion of tooth length/papilla interdental papillae during smilinglength (Fig 4) was found to be, is a critical component to the diag-on average, 40% of the length of nosis and treatment of the esthetic-the tooth from the gingival zenith restorative patient requiring either(highest point of the midfacial gin- interdisciplinary reconstructive orgival margin) to the incisal edge.8 conformative dental care. The authors have defined the The purposes of this studyterm interdental smile line (ISL) as were to determine the following:the position of the maxillary vermil- the overall percentage of patientsion border relative to the interdental aged 10 to 89 years who displaypapillae. Two basic categories are the interdental papillae of the max-defined: high interdental smile line illary anterior teeth during smiling(HISL) and low interdental smile line to establish a normative value; any(LISL). ISL analysis is differentiated differences between age groupsfrom traditional smile line analysis, with respect to the display of thewhich relates the postural position interdental papillae during smiling,of the vermilion border of the up- thereby evaluating the effects ofper lip to the clinical crown length aging on the amount of interdentalof the maxillary anterior teeth. The papillary display; and if gender dif-ISL exclusively assesses the relative ferences affect the presence or ab-position of the labial tissues to the sence of interdental papillae duringrelative position of the interdental smiling. Volume 32, Number 4, 2012 © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 5. 378 a b cFigs 5a to 5c    Digital single-lens reflex smile photographs were taken from the (a) right frontal-lateral, (b) frontal, and (c) left-frontal lateralperspectives to assess the presence vs absence of interdental papillae. Note that from the frontal perspective, it is not immediately apparentwhether the interdental papillae are displayed.Method and materials analyzed, and carefully evaluated Definition of terms by visual examination for the pres-Inclusion criteria were complete ence or absence of display of in- Gingival smile linemaxillary and mandibular arches terdental papillae and midfacial A high gingival smile line (HGSL)up to and including the first molar. gingiva. Images were digitally en- displays the midfacial tissues of allA total of 420 male and female pa- larged to provide greater visual ac- maxillary anterior teeth upon smil-tients were randomly selected, with curacy. The vermilion border of the ing (Fig 6), whereas a low gingivalages ranging from their teens to upper lip was evaluated relative to smile line (LGSL) does not (Fig 7).80s. Groupings of each age were di- the display or absence of the inter- CB-GSL does not display the midfa-vided into cohorts ranging from the dental papilla and midfacial gingiva cial gingiva of the maxillary centralsecond to the ninth decade of life. of the maxillary teeth. incisors but reveals the midfacialTwo independent examiners evalu- Two basic categories were de- gingival tissues of the maxillaryated digital photographic records fined: HISL and LISL. A third variant lateral incisors and/or those distalproviding a right frontal-lateral, category, referred to as Cupid’s bow upon smiling (Fig 8).frontal, and left frontal-lateral smile smile line, was defined as when theview of each patient (Figs 5a to upper lip displayed the interden- Interdental smile line5c). Exclusion criteria consisted of tal papillae distal to the central An HISL displays any portion of thepatients with a previous history of incisors while simultaneously cov- interdental papillae of the maxillaryperiodontal disease, trauma, or ering the interdental papilla and/ anterior teeth upon smiling (Fig 9),iatrogenic dentistry resulting in an or midfacial gingiva of the maxil- whereas an LISL does not (Fig 10).alteration of the attached gingival lary central incisors upon smiling. A CB-ISL does not display the in-tissues. Additionally, patients with The outline shape yields a double terdental papillae of the maxillaryatypical conditions of the labial tis- curve resembling an archer’s bow, central incisors but reveals that ofsues, such as traumatized lips, cos- hence the term “Cupid’s bow smile the maxillary lateral incisors and/metic lip augmentation, or a history line.” Two subclasses were noted: or those distal to these teeth uponof previous surgery to the maxillary Cupid’s bow interdental smile line smiling (Fig 11).anterior region, were excluded as (CB-ISL) and Cupid’s bow gingivalwell. Each subject was compared, smile line (CB-GSL).The International Journal of Periodontics & Restorative Dentistry © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 6. 379Figs 6 to 11    Gingival and interdental smile line classification.Fig 6    High gingival smile line (HGSL). Fig 7    Low gingival smile line (LGSL). Fig 8    Cupid’s bow gingival smile lineAll of the midfacial gingival tissues are None of the midfacial gingival tissues are (CB-GSL). Absence of display of the midfa-displayed during smiling. displayed during smiling. cial gingival tissues of the central incisors combined with the display of midfacial gingival tissues distal to those teeth during smiling.Fig 9    High interdental smile line (HISL). Fig 10    Low interdental smile line (LISL). Fig 11    Cupid’s bow interdental smile lineAll of the interdental papillae are displayed None of the interdental papillae are dis- (CB-ISL). Absence of display of the inter-during smiling. played during smiling. dental papillae between the central incisors combined with the presence of interdental papillae distal to these teeth.Results papillae at or distal to the lateral incisors while simultaneously not re-Sex variability revealed that females vealing either the midfacial gingivahad a higher percentage of HGSL and/or the interdental papilla be-compared to males (76% vs 24%). tween the maxillary central incisors. When all ages were grouped A greater number of subjectstogether, 72% of patients (303 of revealed both HGSL and HISL in420) were classified as having an the younger age cohorts comparedLGSL and 28% as having an HGSL. to the older age cohorts (Fig 12).Ninety-one percent of patients The results of this study foundwere found to display the interden- that 87% of all patients classified astal papillae during smiling in both having an LGSL were found to havehigh and low gingival smile groups. an HISL, which reveals all maxillaryEighteen percent of all patients were interdental papillae upon smilingfound to display the interdental (Fig 13). Volume 32, Number 4, 2012 © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 7. 380 100 100 90 90 80 80 70 70 60 60 % % 50 50 40 40 30 30 20 20 10 10 0 0 2 3 4 5 6 7 8 9 HISL LISL Decade of lifeFig 12    Percentage of subjects with a high interdental smile line Fig 13    Subjects with a low gingival smile line (LGSL) according to(HISL) by decade of life. whether the interdental papillae are displayed when smiling. High interdental smile line (HISL) = papillary display; low interdental smile line (LISL) = no papillary display.Discussion understanding and meaning of this originated from an analysis of prior subjective topic. There have been great artists and philosophers.16,17The evolution and advancement two main approaches: subjective The study of beauty in ancientof esthetic dentistry is one of the viewer testing to establish esthetic Greece was documented throughmore important changes to occur criteria to form specific parameters the writings of Plato (427 to 347 BC)in the dental profession over the and measurable objective criteria and Artistotle (384 to 322 BC), whopast 50 years. Esthetic dentistry, to identify normative values estab- questioned the intrinsic meaning ofalthough not recognized as a for- lishing acceptable ideal esthetic beauty as a subjective discourse.18mal specialty, is understood as a outcomes. It is understood that The classic Greek artists of the fifthgeneral approach to enhancing or through the combination of both of and fourth centuries BC estab-establishing the ideals of beauty these approaches, essential traits lished strict tenants for ideal bodilyin combination with optimal health have been identified to effectively proportions, creating a subjectiveand function of the oral cavity. This establish a set of meaningful es- appreciation of beauty as well.may be accomplished through a thetic criteria for diagnosis and Leonardo da Vinci is credited withvariety of different treatment mo- treatment. introducing a mathematic modeldalities using various disciplines The earliest studies performed of the explanation of human fa-within dentistry. Several of the on the topic of facial form, expres- cial form in the 15th century.19 Therecognized specialties of dentistry sion, and esthetics are found in knowledge of past centuries estab-over the past two centuries have the orthodontic and prosthodontic lished the foundation for our con-examined the characteristics of the literature in which a formalized un- temporary understanding of dentalpatient smile to elucidate greater derstanding of individual beauty facial esthetics.The International Journal of Periodontics & Restorative Dentistry © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 8. 381 Contemporary smile analy- cal crown length and the associated upper lip was either coincident tosis can be attributed to a series of gingiva.2 A comparative analysis of the gingival margin of the centralpublications appearing in the den- 454 full-face photographs of sub- incisors (ie, average smile type) ortal literature in the 1970s.4,20 These jects ranging from 20 to 30 years displayed 1 to 2 mm of direct gin-articles shifted the focus from gen- of age was performed. The survey gival tissue (ie, high smile type)eral facial form toward identifying reported that 48 (10.57%) subjects with the numeric mode of +1 mm.specific elements of an individual’s were classified as having a high Male patients predominantly didsmile. The basic components that smile, 313 (68.94%) as having an not display gingival tissues (ie, lowwere initially reviewed consisted average smile, and 93 (20.48%) as smile type) with the numeric modeof midline positioning, presence having a low smile. Sex dimorphism of patients displaying –1 mm.25or absence of the buccal corridor, with respect to smile lines was also The authors concur that there isrelationship of the maxillary inci- provided. Low smile types were supporting evidence of an agingsal edges to the curvature of the predominantly a male character- phenomenon that with increasedlower lip, and the relationship of istic, while high smile types were age, subjects progressively displaythe amount of clinical crown length a female characteristic. This study less maxillary incisor clinical crowndisplayed upon smiling.21–23 Hulsey provided the normative distribution length and/or gingival tissue dur-reported findings from a random- values of display of clinical crown ing smiling, as was originally de-ized visual study using 40 subjects length for subjects in their 20s.2 fined by Vig and Brundo in 1978.4with the objective of analyzing the Peck et al conducted two stud- This article identifies a new char-lip-to-teeth relationship in a fron- ies that further examined the re- acteristic of smile line analysis thattal smile using photographs.20 The lationship of the maxillary central has not been described previouslyevaluation was conducted using 10 incisor clinical crown length, ver- in detail. The ISL is defined as the re-independent reviewers providing milion border of the upper lip, and lationship of the vermilion border ofsubjective scoring for attractiveness the presence or absence of associ- the upper lip to the visual presenceof each subject. Hulsey noted that ated gingival tissue display of these or absence of the interdental papil-the majority of the highest scores teeth.24,25 A total of 115 subjects lae during smiling. Three catego-for attractiveness were reported with a mean age of 15 years were ries have been identified: the HISL,for those subjects in which the ver- clinically evaluated with direct mea- LISL, and a third variant referred tomilion border of the upper lip was surements of the frontal soft tissue as CB-ISL and based on the uniquecoincident with the free gingival relationships to the maxillary inci- shape of the maxillary lip relativemargin of the maxillary central inci- sors, and three sagittal radiographic to the soft tissues. The data hereinsors. Lip positions deviating above cephalometric measurements were represent normative values collect-or below the free gingival margin recorded.24 Similar to previous ed for males and females betweenwere scored with increasingly lower studies, the position of the ver- the ages of 10 and 89.values with increasing distances, in- milion border of the upper lip was Analysis of this data revealsdicating that full display of the clini- compared to the location of the that 91% of subjects evaluated dis-cal crown is a desirable feature of a gingival margin and the location of played an HISL, revealing the in-patient’s smile.20 the maxillary incisal edge.25,26 The terdental papillae for patients with Tjan et al defined three general studies provided supporting data high, average, or low smile linescategories of normalcy for smile of normative values for patients in as defined by Tjan and cowork-type; high, average, and low smiles their 20s, in which sex dimorphism ers.2 The high frequency noted inwere defined based on the relative was a consistent finding with ear- this study across all patient groupsposition of the vermilion border of lier studies. Female patients pre- identifies a smile characteristicthe upper lip to the display of clini- dominantly demonstrated that the that should be expected in the Volume 32, Number 4, 2012 © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 9. 382 Fig 14    Excessively long contacts relative to the lack of interdental papillae display, which is not uncommon when the interdental papil- lae are not present because of interdental recession secondary to periodontal disease. It gives an unnatural form to the teeth that is visually displeasing.Fig 15a    Pretreatment digital photograph of a patient lacking visual Fig 15b    Adjunctive orthodontic therapy (forced eruption) was em-display of the interdental papillae because of interproximal attachment ployed to bring the lost interdental papillae incisally into the smileloss. The contact areas were increased apically in an effort to eliminate view, thereby reestablishing the interdental smile line.the appearance of black triangles between the anterior teeth.unaltered smile of the majority of (87%). Therein lies a misconception average or low smile line (LGSL) ispopulations across all age groups. by many dentists that the treatment often the difference between a vi-Therefore, the display of the inter- of the LGSL patient represents a sually pleasing and an unattractivedental papillae during smiling rep- lesser esthetic challenge owing to artificial smile where the contactresents the most important smile the lack of visual midfacial tooth and area dimensions are usually in-characteristic that should be as- gingival display. It is these authors’ creased (Fig 14). Recognizing thesessed for dental patients under- perspective that the presence of importance of the ISL and having agoing esthetic dentistry, especially the interdental papillae in patients classification that identifies this keysince the frequency of a high smile with low and average smile lines is esthetic element of a patient’s smileline (HGSL) was relatively low. the most important component to provides the dentist with greater Of particular significance is the the maintenance and/or re-creation awareness of the treatment goalshigh percentage of patients with a of an optimal esthetic outcome. in the esthetic-restorative manage-low smile line (LGSL) that display the Absence of the interdental papillae ment of the dental patient (Figs 15ainterdental papillae during smiling during smiling from patients with an and 15b).The International Journal of Periodontics & Restorative Dentistry © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
  • 10. 383Conclusions References 13. Magne P, Gallucci GO, Belser UC. Ana- tomic crown width/length ratios of unworn  1. Frush JP, Fisher RD. The dynesthetic in- and worn maxillary teeth in white subjects.In a group of 420 patients between terpretation of the dentogenic concept. J Prosthet Dent 2003;89:453–461. 14. Hasanreisoglu U, Berksun S, Aras K, Arslanthe ages of 10 and 89, the visual J Prosthet Dent 1958;8:558–581.   2. Tjan AH, Miller GD, The JG. Some esthet- I. An analysis of maxillary anterior teeth:display of the interdental papillae Facial and dental proportions. J Prosthet ic factors in a smile. J Prosthet Dent 1984;during smiling was present 91% 51:24–28. Dent 2005;94:530–538.  3. Van Der Geld P, Oosterveld P, Bergé 15. Zagar M, Knezovic Zlataric DK. Influence ´ ´of the time. Even in those patients of esthetic dental and facial measure- SJ, Kuijpers-Jagtman AM. Tooth displayclassified as having an LGSL, 87% and lip position during spontaneous and ments on the Caucasion patients’ satisfac- tion. J Esthet Restor Dent 2011;23:12–20.were found to have visual display posed smiling in adults. Acta Odontol Scand 2008;66:207–213. 16. Angle EH. The Treatment of Malocclusionof the interdental papillae when of the Teeth and Fractures of the Maxillae,   4. Vig RG, Brundo GC. The kinetics of anteri-smiling. Therefore, this study dem- or tooth display. J Prosthet Dent 1978;39: ed 6. Philadelphia: SS White, 1900. 502–504. 17. Boucher CO, Hickey JC, Zarb GA.onstrates that the visual display of Prosthodontic Treatment for Edentulous   5. Al-Jabrah O, Al-Shammout R, El-Naji W,interdental papillae is an important Al-Ajarmeh M, Al-Quran AH. Gender dif- Patients, ed 7. St Louis: Mosby, 1975. 18. Beardsley MC. Aesthetics from Classicalsmile feature that is present in the ferences in the amount of gingival display during smiling using two intraoral dental Greece to the Present. New York: Mac-overwhelming majority of patients millan, 1966. biometric measurements. J Prosthodontreceiving treatment. Preservation 2010;19:286–293. 19. Huntley HE. The Divine Proportion: A   6. Dickens ST, Sarver DM, Proffit WR. Study in Mathematical Beauty. New York:and maintenance of this anatomi- Dover, 1970. Changes in frontal soft tissue dimensionscal structure should be given par- of the lower face by age and gender. 20. Hulsey CM. An esthetic evaluation of lip- teeth relationships present in the smile.ticular attention. The ISL should be World J Orthod 2002;3:313–320.  7. Chu SJ, Tan JHP, Stappert CFJ, Tarnow Am J Orthod 1970:57;132–144.considered an important esthetic 21. Kokich VO Jr, Kiyak HA, Shapiro PA. DP. Gingival zenith positions and levelsparameter of smile analysis and of the maxillary anterior dentition. J Es- Comparing the perception of dentists thet Restor Dent 2009;21:113–120. and lay people to altered dental esthet-should be given equal consider- ics. J Esthet Dent 1999;11:311–324.  8. Chu SJ, Tarnow DP, Tan JHP, Stappertation to the traditional midfacial CFJ. Papilla proportions in the maxillary 22. Zachrisson BU. Esthetic factors involved in anterior tooth display and the smile:smile determinants previously de- anterior dentition. Int J Periodontics Re- storative Dent 2009;29:385–393. Vertical dimension. J Clin Orthod 1998;fined for dentistry. 23:432–445.   9. Stappert C, Tarnow DP, Tan JHP, Chu SJ. Proximal contact areas of the maxillary 23. Janson G, Branco NC, Fernandes TM, anterior dentition. Int J Periodontics Re- Sathler R, Garib D, Lauris JR. Influence of storative Dent 2010;30:471–477. orthodontic treatment, midline position, 10. Chu SJ. A biometric approach to predict- buccal corridor and smile arc on smile able treatment of clinical crown discre- attractiveness. Angle Orthod 2011;81: pencies. Pract Proced Aesthet Dent 2007; 153–161. 19:401–409. 24. Peck S, Peck L, Kataja M. The gingival 11. Sterrett JD, Oliver T, Robinson F, Fortson smile line. Angle Orthod 1992;62:91–100. W, Knaak B, Russell CM. Width/length 25. Peck S, Peck L, Kataja M. Some vertical ratios of normal clinical crowns of the lineaments of lip position. Am J Orthod maxillary anterior dentition in man. J Clin Dentofacial Orthop 1992;101:519–524. Periodontol 1999;26:153–157. 26. Passia N, Blatz M, Strub J. Is the smile line 12. Fayyad MA, Jamani KD, Agrabawi J. Ali a valid parameter for esthetic evaluation? Geometric and mathematical propor- A systematic literature review. Eur J Esthet tions and their relations to maxillary ante- Dent 2011;6:314–327. rior teeth. J Contemp Dent Pract 2006;7: 62–70. Volume 32, Number 4, 2012 © 2012 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY. NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.