Arnett - Soft Tissue Cephalometric Analysis

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  • This article will present a technique for softtissue cephalometric analysis. The analysis is a radi-ographic instrument that was developed directly fromthe philosophy expressed in Arnett and Bergmans1,2Facial keys to orthodontic diagnosis and treatmentplanning, published in the AJO/DO in April and May of1993. Familiarity with those articles is helpful in under-standing this article. As with the Facial Keys articles,this article emphasizes soft tissue facial measurementand treatment planning.

    Many authors have suggested utilizing soft tissueanalysis as a reliable guide for occlusal treatment andattendant soft tissue changes.1-12 Arnett and Bergmanpresented the Facial Keys to Orthodontic Diagnosis andTreatment Planning as a three-dimensional clinicalblueprint for soft tissue analysis and treatment plan-ning.1,2

    MATERIAL AND METHODSForty-six adult white models comprise the cephalo-

    metric database for this analysis (20 male, 26 female).The model cephalograms were digitized and mean val-

    ues, SDs, and P values were calculated with MicrosoftExcel. All models had natural Class I occlusions andwere viewed by one of us (G.W.A.) as reasonablyfacially balanced. A distinction was made during selec-tion between quality of facial parts (hair, eyes, skin,etc) and position of facial parts. Models were chosenfor inclusion only on the basis of balance of facialparts, and quality of parts (ie, beautiful eyes) were dis-regarded. To initiate the Soft Tissue CephalometricAnalysis (STCA), the models were first assessed clini-cally,1,2 in natural head position, seated condyles, andwith passive lips.

    Proper clinical examination posturing was impera-tive to insure the reliability of the soft tissue cephalo-metric analysis that followed. The STCA was not usedwithout clinical input; it required clinical facial assess-ment to augment and elucidate cephalometric findings.First, facial examination was used as described byArnett and Bergman,1,2 with particular emphasis onmidface structures that do not show on standardcephalometric analysis. In particular, orbital rim, sub-pupil, and alar base contours were noted to indicateanteroposterior position of the maxilla.

    Next, in preparation for the cephalometric radi-ograph, metallic markers were placed on the rightside of the face to mark key midface structures. Themetallic beads were placed on the models midfacewith the following routine. The orbital rim markerwas placed directly over the osseous orbital rim anddirectly under the pupil with the eye in straight-aheadgaze. Cheekbone marking required two perspectives.First, examined from the left in 34 view, the rightmalar height of contour was marked with ink. Then,with the examiner standing directly in front of the

    239

    ORIGINAL ARTICLE

    Soft tissue cephalometric analysis: Diagnosis and treatmentplanning of dentofacial deformity

    G.William Arnett, DDS, FACD,a Jeffrey S. Jelic, DMD, MD,b Jone Kim, DDS, MS,c David R. Cummings, DDS,dAnne Beress, DMD, MS,e C. MacDonald Worley, Jr, DMD, MD, BS,f Bill Chung, DDS,g andRobert Bergman, DDS, MShSanta Barbara, Camarillo, Loma Linda, and Mission Viejo, Calif, and Dalton and Kennesaw, Ga

    This article will present a new soft tissue cephalometric analysis tool. This analysis may be used by theorthodontist and surgeon as an aid in diagnosis and treatment planning. The analysis is a radiographicinstrument that was developed directly from the philosophy expressed in Arnett and Bergman Facial keys toorthodontic diagnosis and treatment planning, Parts I and II (Am J Orthop Dentofacial Orthod 1993;103:299-312 and 395-411). The novelty of this approach, as with the Facial Keys articles, is an emphasison soft tissue facial measurement. (Am J Orthod Dentofacial Orthop 1999;116:239-53)

    aClinical Instructor and Lecturer, UCLA, USC, Loma Linda University, and Uni-versity Medical Center at Fresno; in private practice; Staff Surgeon at St. FrancisMedical Center, and President, Arnett Facial Reconstructions Courses, Inc.bFellowship program at Dr Arnetts office, Santa Barbara, Calif.cIn private practice, Santa Barbara, Calif.dAssociate, Drs Moody and Nicholls, Mission Viejo, Calif.eResident, Loma Linda University, Department of Orthodontics.fIn private practice, Kennesaw, Ga; and Staff Surgeon, Promina Kennestone Hospital.gIn private practice, Dalton, Ga.hIn private practice, Camarillo, Calif.Reprint requests to: Dr G. William Arnett, 9 East Pedregosa St, Santa Barbara,CA 93101Copyright 1999 by the American Association of Orthodontists.0889-5406/99/$8.00 + 0 8/1/93276

  • 240 Arnett et al American Journal of Orthodontics and Dentofacial OrthopedicsSeptember 1999

    Fig 1. Dentoskeletal factors: upper incisor to maxillary occlusal plane, lower incisor to mandibularocclusal plane, maxillary occlusal plane, overbite, and overjet are represented.The dentoskeletal fac-tors, to a large extent, control esthetic outcome.

    Fig 2. Soft tissue structures: tissue thickness at upper lip, lower lip, Pogonion, and Menton are depicted.Soft tissue thickness and dentoskeletal factors determine the profile. Upper lip angle and nasolabial angleare depicted.These soft tissue structures are altered by movement of the incisor teeth.These angles shouldbe studied before orthodontic overjet correction to assess the potential for changes out of normal range.

  • American Journal of Orthodontics and Dentofacial Orthopedics Arnett et al 241Volume 116, Number 3

    patient, a metal bead was placed at the intersection ofthe right malar height of contour ink mark and a ver-tical line through outer canthus. The alar base markerwas then placed in the deepest depression at the alarbase of the nose. The subpupil marker was situateddirectly below the straight ahead gaze of the pupil.Vertically, the subpupil marker was placed one halfthe vertical distance between the orbital rim and alarbase markers. These essential midface structures,although normally lost on traditional headfilms, weremetallically marked on the headfilm and became thecornerstone to our cephalometric midface diagnosisand treatment planning. The neck-throat point wasthen localized, and a metal marker was placed in thatposition.

    With the midface structures marked, a lateral head-

    film was obtained with the model positioned in naturalhead position,1,2,13-17 seated condyle, and with passivelips. Lundstrm and Lundstrm18 noted that despitecareful natural head position instructions, somepatients assume an unnatural head position. Accord-ingly, these patients need adjustment to natural headorientation18 by experienced clinicians. As noted byLundstrm and Lundstrm, our models also assumedhead positions that were obviously not a natural headposition. These headfilms, as per Lundstrm and Lund-strm, were leveled to natural head orientations.18

    The True Vertical Line (TVL) was then established.The line was placed through subnasale and was per-pendicular to the natural horizontal head position.15Soft tissue landmarks, those reported as important inthe Facial Keys articles were then marked on the

    Table I. Soft tissue cephalometric analysis Mean SD Females Mean SD Males Female to male difference signifiant when >.05

    Dentoskeletal factorsMx occlusal plane 95.6 1.8 95.0 1.4 .1789Mx1 to Mx occlusal plane 56.8 2.5 57.8 3.0 .2585Md1 to Md nocclusal plane 64.3 3.2 64.0 4.0 .7764Overjet 3.2 .4 3.2 .6 .6371Overbite 3.2 .7 3.2 .7 .7481

    Soft tissue structureUpper lip thickness 12.6 1.8 14.8 1.4 3.388-E05Lower lip thickness 13.6 1.4 15.1 1.2 .0004Pogonion-Pogonion 11.8 1.5 13.5 2.3 .0086Menton-Menton 7.4 1.6 8.8 1.3 .0019Nasolabial angle 103.5 6.8 106.4 7.7 .1937Upper lip angle 12.1 5.1 8.3 5.4 .0197

    Facial lengthNasion-Menton 124.6 4.7 137.7 6.5 8.916E-09Upper lip length 21.0 1.9 24.4 2.5 1.024E-05Interlabial gap 3.3 1.3 2.4 1.1 .0214Lower lip length 46.9 2.3 54.3 2.4 2.158E-13Lower 1/3 of face 71.1 3.5 81.1 4.7 3.170E-09Overbite 3.2 .7 3.2 .7 .7481 Mx1 exposure 4.7 1.6 3.9 1.2 .0417Maxillary height 25.7 2.1 28.4 3.2 .0026Mandibular height 48.6 2.4 56.0 3.0 8.573E-11

    Projections to TVLGlabella 8.5 2.4 8.0 2.5 .5246Orbital rims 18.7 2.0 22.4 2.7 1.060E-05Cheek bone 20.6 2.4 25.2 4.0 7.405E-05Subpupil 14.8 2.1 18.4.0 1.9 2.266E-07Alar base 12.9 1.1 15.0 1.7 6.054E-05Nasal projection 16.0 1.4 17.4 1.7 .0052Subnasale 0 0 0A point .1 1.0 .3 1.0 .6629Upper lip anterior 3.7 1.2 3.3 1.7 .3836Mx1 9.2 2.2 12.1 1.8 1.064E-05Md1 12.4 2.2 15.4 1.9 1.312E-05Lower lip anterior 1.9 1.4 1.0 2.2 .1065B point 5.3 1.5 7.1 1.6 .0004Pogonion 2.6 1.9 3.5 1.8 .1294

  • 242 Arnett et al American Journal of Orthodontics and Dentofacial OrthopedicsSeptember 1999

    cephalogram. The midface metallic landmarks werealso identified as new landmarks on the headfilm.Important hard tissue landmarks were then identifiedon the cephalogram. The vertical or horizontal positionof soft tissue and hard tissue landmarks were then mea-sured relative to the models natural horizontal headposition or TVL.

    RESULTSOn the basis of the cephalometric soft and hard tis-

    sue landmarks measured on the 46 facially balanced

    white models, dentoskeletal, soft tissue, vertical, pro-jection, and facial harmony norms and SDs were estab-lished. Table I lists the variables, means, SDs, and Pvalues.

    Statistical analysis of the differences betweenmales and females was done with t testing. A level ofsignificance of 5% was assigned and P values weredetermined. Statistical analysis revealed that males andfemales are facially similar in some measures but dif-ferent in others (Table I). Dentoskeletal means werenot statistically different for males and females. All

    Fig 3. Facial lengths: key facial lengths are depicted. Soft tissue lengths include facial height (Na toMe), lower one-third height (Sn to Me), upper lip l