To assess the role of lateral cephalometric films in the evaluation of orth
odontic patients, 16 certified orthodontists examined 80 sets of dental cas
ts and lateral cephalograms. The patients included 5 subgroups: Class I wit
h mild crowding, Class II Division 2, Class III, open bites, and bimaxillar
y protrusion. A 5-point Visual Analogue Scale was used to assess the degree
of severity and difficulty of each case, Severity was defined as the degre
e of deviation from ideal occlusion, while difficulty was defined as the pr
obability of attaining an ideal occlusion when all treatment options were a
vailable. The examiner then chose one or more of the following treatment op
tions: growth modification, extraction, nonextraction, and surgery. All exa
miners scored the degree of severity and difficulty of each case with casts
only at Time 1 (T1), then with casts and cephalograms at Time 2 (T2). The
observed ratings from the Visual Analogue Scale were scored by using the Ra
sch model, which transforms the nonlinear ordinal ratings to a linear inter
val scale. Intersubgroup differences and differences between T1 and T2 diff
iculty and severity were assessed by using a 5 x 2 repeated measures analys
is of variance. A paired t test examined the amount and direction of the di
fferences between T1 and T2 of each subgroup. Multiple contingency tables w
ere used to compare treatment option changes between all subgroups at each
time. Severity and difficulty scores highly correlated. Analysis of varianc
e showed significant differences among subgroups for both severity and diff
iculty; however, there were significant time differences for severity only.
Paired t tests revealed a small increase in severity for the bimaxillary p
rotrusive group and small but significant decreases for the subgroups Class
II Division 2 and Class III when cephalograms were added. The multiconting
ency table analysis demonstrated that a significant number of examiners did
change their treatment options at T2 for bimaxillary protrusive, nonextrac
tion, and Class II Division 2 patients. It was concluded that lateral cepha
lometric films showed a significant influence on a clinician's determinatio
n on severity of some types of orthodontic malocclusions.