Una Modificación En La Maloclusion De Angle S

V IEWPOINT

Angle classification revisited 2: A modified
Angle classification
M orton I. Katz, DDS*

Washhlgton, D.C.
E dward Angle, in his classification of malocclusions, appears to have made Class I a range of
a bnormality, not a point of ideal occlusion. Current goals of orthodontic treatment, however, strive for
t he designation "Class I occlusion" to be synonymous with the pointof ideal intermeshing and not a
b road range. If contemporary orthodontists are to continue to use Class I as a goal, then it is
a ppropriate that Dr. Angle's century-old classification, be modified to be more precise. (AM J ORTHOD
DENTOFAC ORTHOP 1992;102:277-84.)

H a v i n g observed inconsistency in the app lication of the Angle classification of malocclusion as
a p ostgraduateorthodontic teacher, I developed a quest ionnaire to test whether the observed inconsistency is
m erely anecdotal or whether orthodontists across the
s pectrum of ages, training, and geographic location
t ruly have problems applying the Angle classification.
T he questionnaire presented 10 buccal views of study
m odels: three ideal interdigitations and seven with varying degrees o f Class II tendency(two of which were
m utilated). A sample was selected of 347 orthodontists
( approximately 5% of active practitioners listed in the
1987 American Association of Orthodontists list of
m embers) selected from every state and distributed
a mong orthodontists trained in the 1960s and before,
t he 1970s, and the 1980s, as well as all chairpersons
o f departments of dental school orthodonticprograms.
T he 77.8% response rate on the single mailing demo nstrated an intense interest in the subject of classific ation reliability. Unfortunately, the statistics showed
a n extremely p o o r reliability of Angle classification
w hen applied by contemporary orthodontists. This
s tudy illustrated that a problem exists with the current
u se of Angle's valuable classification. ~ I havefurther
a ttempted to supplement the Angle method to address
t he weaknesses observed, while maintaining the
s trengths of the Angle method.
W hy is the classification of malocclusion important?
F irst, classification is an essential communication tool
b etween dental school professor and student, between
p ractitioners, and between practitioner and insurance
c ompany or governmentbureaucracy. It is essential that

*Associate Professor, Postgraduate Clinical Director, Department of Orthodontics. Howard University College of Dentistry, Washington. D.C.
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e veryone "speak the same language." No one has diff iculty classifying the extremes of a full Class II and a
f ull Class III. However, the gray area of Class I is
s ubject to much confusion and inconsistency. Second,c lassification has a significant effect on patient treatm ent. Once a patient is classified, the practitioner will
t end, almost unconsciously, to apply treatment mec hanics appropriate to that classification. Even though
m odel analysis, especially buccal interdigitation, is but
a s mall part of the complete orthodontic diagnosis, the
d ecision to use Class II or Class III mechanicsinvaria bly is strongly influenced by the perceived Angle class ification of the patient. Third, if one of the goals in
t he treatment of a malocclusion is to achieve Class I,
t here must be a consensus among orthodontists as to
w hat constitutes ideal occlusion, and Class I must be
r edefined to agree with the prototype standard. If every
o rthodontist has a different idea of what ideal buccali nterdigitation means, then the dental specialty of orthod ontics has no standardized method by which to evalu ate successful or unsuccessful treatment. Angle dev eloped his classification 100 years ago to eliminate
t he anarchy that existed in the specialty. Considering
t he current level of disagreement as to what constitutes
C lass I, and what describes ideal occlusion, is the Angle
c...