Arnetts analysis

ARNETT’S ANALYSISARNETT’S ANALYSIS
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IntroductionIntroduction
Facial keys to orthodontic diagnosisFacial keys to orthodontic diagnosis
and treatment planningand treatment planning
G. William Arnett, DDS and Robert T.G. William Arnett, DDS and Robert T.
Bergman, DDS, MS Santa Barbara, CaliforniaBergman, DDS, MS Santa Barbara, California
(April May 1993)(April May 1993)

PurposePurpose
(1) To present an organized, comprehensive(1) To present an organized, comprehensive
clinical facial analysis andclinical facial analysis and
(2) To discuss the soft tissue changes(2) To discuss the soft tissue changes
associated with orthodontic and surgicalassociated with orthodontic and surgical
treatments of malocclusiontreatments of malocclusion

 Comprehensive facial trait analysis should be used toComprehensive facial trait analysis should be used to
enhance diagnosis, treatment planning, and quality ofenhance diagnosis, treatment planning, and quality of
results for both surgical and nonsurgical patients.results for both surgical and nonsurgical patients.
 In addition, this method provides a tool forIn addition, this method provides a tool for
organization, understanding, and communicationorganization, understanding, and communication
between the orthodontist, maxillofacial surgeon, andbetween the orthodontist, maxillofacial surgeon, and
patient.patient.
 With this analysis, cosmetic problems can beWith this analysis, cosmetic problems can be
optimally corrected and orthodontic tooth movementsoptimally corrected and orthodontic tooth movements
that produce esthetic decline can be avoided.that produce esthetic decline can be avoided.

With this system, the predictability of facialWith this system, the predictability of facial
results should be much better than just withresults should be much better than just with
cephalometric treatment and/or modelcephalometric treatment and/or model
guidelines.guidelines.
 In many instances, the facial examinationIn many instances, the facial examination
reveals cosmetic problems that indicatereveals cosmetic problems that indicate
skeletal disharmony and the need forskeletal disharmony and the need for
surgery.surgery.
In addition, this system can identify cosmetic-In addition, this system can identify cosmetic-
skeletal disharmonies that precludeskeletal disharmonies that preclude
successful orthodontic correction.successful orthodontic correction.

Dawson(1985).

The relaxed lip position is obtained whileThe relaxed lip position is obtained while
the patient is in centric relation by thethe patient is in centric relation by the
following method (Burstone 1967):following method (Burstone 1967):
1. Ask the patient to relax.1. Ask the patient to relax.
2. Stroke the lips gently.2. Stroke the lips gently.
3. Take multiple measurements on different3. Take multiple measurements on different
occasions.occasions.
4. Use casual observation while the patient4. Use casual observation while the patient
is unaware of being observed.is unaware of being observed.

 Nineteen facial traits were selected for thisNineteen facial traits were selected for this
examination.examination.
 Two views of the patient are used for identification ofTwo views of the patient are used for identification of
problems in three planes of space:problems in three planes of space:
I. FrontalI. Frontal
A. Relaxed lipA. Relaxed lip
B. Functional analysisB. Functional analysis
1. Closed lip1. Closed lip
2. Smile2. Smile
II. ProfileII. Profile
Relaxed lipRelaxed lip www.indiandentalacademy.comwww.indiandentalacademy.com

Outline form and symmetryOutline form and symmetry
 Bigonial width is
approximately 30% <
bizygomatic
dimension.
 The height to width
proportion is 1.3:1 for
females and 1.35:1 for
males(Farkas 1981)
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Facial levelFacial level

Midline alignmentsMidline alignments

Facial one thirdsFacial one thirds
The thirds are within a range of 55 to 65 mm, vertically.

Lower one-third evaluationLower one-third evaluation
a. Upper and lowera. Upper and lower
lip lengthslip lengths
 ULL 19 to 22 mmULL 19 to 22 mm
 LLL 38 to 44 mm.LLL 38 to 44 mm.
 The normal ratio ofThe normal ratio of
upper to lower lip isupper to lower lip is
1:2.11:2.1

b. Upper tooth to lipb. Upper tooth to lip
relationshiprelationship
1 to 5 mm.

c. Interlabial gapc. Interlabial gap
1 to 5 mm.

d. Closed lip position.d. Closed lip position.
e. Smile position lip level.e. Smile position lip level.
 Ideal exposure with smile is 3/4 of the crownIdeal exposure with smile is 3/4 of the crown
height to 2 mm of gingivaheight to 2 mm of gingiva
 females > malesfemales > males
 Variability in gingival exposure is related to (1)Variability in gingival exposure is related to (1)
lip length, (2) vertical maxillary length, (3)lip length, (2) vertical maxillary length, (3)
maxillary anatomic crown length, and (4)maxillary anatomic crown length, and (4)
magnitude of lip elevation with smile.magnitude of lip elevation with smile.

II. PROFILE VIEWII. PROFILE VIEW
Profile angleProfile angle
Class I occlusion presents a
total facial angle range of
165° to 175°. Class II angles
are less than 165°, and Class
III are greater than 175°

Nasolabial angleNasolabial angle
85° to 105°.

Maxillary sulcus contourMaxillary sulcus contour

Mandibular sulcus contourMandibular sulcus contour

Orbital rimOrbital rim

Cheekbone contourCheekbone contour

Nasal base-lip contourNasal base-lip contour

Nasal projectionNasal projection
16 to 20 mm

Throat length and contourThroat length and contour

Subnasale-pogonion line (Sn-Subnasale-pogonion line (Sn-
Pg')Pg')
 Burstone reported thatBurstone reported that
the upper lip is in frontthe upper lip is in front
of the Sn-Pg' line by 3.5of the Sn-Pg' line by 3.5
mm ± 1.4 mm, and themm ± 1.4 mm, and the
lower lip is in front oflower lip is in front of
the line by 2.2 mm ± 1.6the line by 2.2 mm ± 1.6
mm.16mm.16

SOFT TISSUE CHARACTERISTICSSOFT TISSUE CHARACTERISTICS
OF COMMON SKELETALOF COMMON SKELETAL
DEFORMITIESDEFORMITIES

CONCLUSIONCONCLUSION
In contrast, this analysis has presented anIn contrast, this analysis has presented an
organized, comprehensive approach toorganized, comprehensive approach to
facial analysis.facial analysis.
 With this analysis normal facial traits areWith this analysis normal facial traits are
maintained and abnormal characteristicsmaintained and abnormal characteristics
are corrected with orthodontics andare corrected with orthodontics and
surgerysurgery

ReferencesReferences
Arnett GW, Bergman RT. Facial Keys toArnett GW, Bergman RT. Facial Keys to
Orthodontic Diagnosis and Treatment PlanningOrthodontic Diagnosis and Treatment Planning
- Part I. AM J ORTHOD DENTOFAC ORTHOP- Part I. AM J ORTHOD DENTOFAC ORTHOP
1993:103:299-312.1993:103:299-312.
Arnett GW, Bergman RT. Facial Keys toArnett GW, Bergman RT. Facial Keys to
Orthodontic Diagnosis and Treatment PlanningOrthodontic Diagnosis and Treatment Planning
- Part II. AM J ORTHOD DENTOFAC ORTHOP- Part II. AM J ORTHOD DENTOFAC ORTHOP
1993:1031993:103

Arnetts analysis

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