ORIGINAL ARTICLES

Routine use of panoramic radiography may not be indicated

solely on the expectation of finding hidden pathologic
conditions not apparent on intraoral radiographs.
Since panoramic radiography does not appear to have a high radiation
dose, however, its broad coverage can be advantageous
for survey purposes or more specific indications such as for viewing
surgical procedures that require healing assessment
such as cysts or osteomyelitis. It also is valuable as
a teaching instrument for patients and students.

Relative discernment of lesions by intraoral

and panoramic radiography

Since 1948 the developm ent of panoram ic radiog

raphy by P aatero ,1 H udson and asso ciates,2 and
other researchers has m ade available to the clini
cian a rapid m eans for viewing the orofacial re
S tu a rt C. W h ite, DDS, PhD gion. Because of the broad coverage achieved,
D o n a ld D. W e issm a n , DDS, Los A ngeles particularly of the zygom atic arches, maxilla,
mandible, and their peripheral structures, this
technique has becom e both popular and valuable,
notw ithstanding the inherent m agnifications and
distortions portrayed.3,4 It has been used for
P anoram ic and intra o ra l p e ria p ica l ra d io g ra p h s routine screening of patients at various institu
w ere com p ared fo r th e ir d e m o n s tra tio n o f p a th tions and private offices.5
o lo g ic c o n d itio n s in patie n ts se eking general den An early evaluation by K raske and M azzerella6
tal care. P anoram ic view s allow ed a d d itio n a l de has shown that the panoram ic radiograph
te c tio n o f n o te w o rth y lesions th a t w ere not detected adequately and grossly dem onstrates resto ra
by in tra o ra l survey in 5.3% o f th e cases reviewed, tions, dental lesions, bone pathology, and config
w ith only 0.1% o r one p a tie n t in 1,000 p o ssib ly re uration, and thus is applicable to forensic identifi
q u irin g trea tm ent. The p a u c ity and lack o f u rgency cation procedures, even if only one quadrant is
of th e p a th o lo g ic c o n d itio n s d isco ve re d solely by available for consideration. It also has been
p a n o ra m ic ra d io g ra p h y sug g e st th a t the e xp e cta shown to be a definite aid both to prosthodontists
tio n o f a high in cid e n ce o f d e te c tio n o f su ch c o n d i in treatm ent planning for com plete and partial
tio n s ca n n o t be used as the sole ra tio n a le fo r the denture prostheses and to oral surgeons in recog
ro u tin e use o f th is pro ce d u re as an a d ju n c t to the nizing condylar fractures and generally providing
in tra o ra l survey. orientation of the oral surgeons working area and
related structures. T hese authors also have re
ported, how ever, that because of lack of defini
tion, finer structures such as the periodontal liga
m ent, lamina dura, and small carious lesions are
not easily seen. D istortion in projection angula
tion, especially of the prem olars, prevents accu

JADA, Vol. 95, Decem ber 1977 1117

rate dem onstration of the alveolar crest and the clinic o f the U C L A School of D entistry. Those
existence of recurrent caries. Because of these who w ere fully edentulous, had a recent history of
inadequacies, they have concluded, panoramic traum a or swelling o f the jaw s, or were referred
radiographs offer limited benefit for periodontal from private dentists because of known or sus
and operative interpretation. pected pathologic conditions were excluded from
H ansen and Johansen7 have reported that it is the study.
only 50% as efficient as an intraoral survey in The panoram ic radiography was perform ed by
detecting apical radiolucent areas. H ow ever, technicians and students using a Siemens O r
Ainam o and Tam m isalo8 have observed that the thopantom ograph* operated at 225 milliamperes
panoram ic radiograph is superior to intraoral seconds (mAs) and from 60 to 85 kilovolts (peak).
views in assessing early horizontal bone loss. T he intraoral periapical surveys, consisting
From these and other reports assessing of 21 films (9 anterior, 8 posterior, 4 bitewing),
panoram ic radiography,911 it seems reasonable to were perform ed by similar personnel using film
state that it has been shown to provide diagnostic holdersf that provided a rectangularly collimated
inform ation different but com plem entary to that paralleling technique. T he X-ray m achines were
provided by intraoral radiography. the S. S. White XRM 90t and G eneral Electric
A s with any radiographic procedure, it is essen 1000, both operated at 12 to 15 mAs and 80 kVp.
tial to evaluate the risk and benefit experienced by T o avoid unnecessary exposure, intraoral
the patient from this technique, both from an indi radiographs were not made of extensively eden
vidual and a population perspective. In 1973 this tulous regions of the arches unless there was spe
question was addressed by Bushong and o th ers,12 cific clinical or radiographic (panoramic) indica
w ho concluded that the panoram ic system they tion.
investigated exposes a volume of critical tissue Panoram ic films (EK , DF-76)U were processed
com parable with that in the now abandoned car autom atically by X-OmatH and intraoral films
diopulm onary screening procedure and, there (E K , D F-55, DF-57)K by hand developing and
fore, is unsuitable for population screening. fixing. Kodak solutions were used throughout.
Equipm ent m anufacturers, how ever, have en The technicians prepared sets of radiographs
couraged the extensive use of panoram ic radiog for study by mounting a periapical survey in black
raphy for all disciplines of dentistry. Some inves film mount** and pairing it with the panoram ic
tigators in oral radiology doubt the advisability of film of the same patient. Each set of radiographs
such universal application because o f the possibil was viewed by one of eight faculty m em bers of the
ity of limited diagnostic benefit. T hey ask, F or oral radiology section under ideal viewing condi
general dental treatm ent, does panoram ic radi tions. The viewing room was dimly lit and all
ography represent an uninform ative diagnostic
redundancy when perform ed in conjunction with
the more accurate, but less encom passing, intra
oral periapical survey? THE AUTHORS

T he purpose of this study was to determ ine the

type and extent of occult pathologic conditions in
the orofacial region observed on a panoram ic
radiograph that are not visualized on an intraoral
periapical survey obtained at the same visit for
patients seeking general dental care (Fig 1). Such
data may assist us in further defining the proper
role panoram ic radiography should play in the
diagnosticians arm am entarium .
WHITE WEISSMAN

Dr. W hite Is chairm an and associate professor,

M aterials and m ethods and Dr. Weissman is lecturer, section of oral
radiology, School of Dentistry and Dental Re
search Institute, University of C alifornia at Los
All radiographs examined in this study were ob Angeles, 90024. Address re print requests to Dr.
tained as a part of the initial clinical diagnostic White.
workup of patients accepted for dental care in the

1118 JADA, Vol. 95, December 1977

 Fig 1 S uperim position of 21 image fields of rectangular collim ated intraoral periapical
survey including bitewings on usual image field of O rthopantom ograph (Siemens*).

extraneous light was masked from the radio did not adequately show the region to be ob
g rap h ^) being studied. F or each set a form was served. An additional 14 w ere invalidated be
com pleted identifying the patients name, age, cause the observer judged that poor panoram ic
and sex; viewing date, observer, and the following radiograph quality made interpretation uncertain.
instructions: T hus, 3,059 sets of radiographs were judged ac
Exam ine the periapical survey first and note ceptable for further analysis.
the presence of pathologic lesions including all O f this total num ber of acceptable sets (3,059),
m anifestations of the common as well as unusual 95 showed no pathologic lesions on the intraoral
conditions. Exam ine the panoram ic radiograph or panoram ic surveys. A nother 2,802 displayed
and note any additional pathologic lesions that pathologic lesions on the intraoral and none addi
have not been seen on the intraoral survey. If tional on the panoramic view. T he majority of
present, note anatom ic location(s) and probable these were merely caries, periodontal disease,
interpretation(s). rarefying osteitis, im pacted teeth, and os
T he data presented in this study were collected teosclerosis, as was expected. O f the remaining
for 18 m onths on consecutive patients when both 162 cases that showed additional notew orthy
radiographic exam inations were available. conditions in the panoram ic survey, it was simi
larly found that the m ajority, 159, continued to
show common dental disease in the intraoral sur
Results vey, whereas 3 showed no conditions at all.
Table 2 shows the type and frequency of the
It may be seen in Table 1 that 3,120 forms were- additional noteworthy pathologic conditions dis
returned by faculty observers. O f these, 29 were covered by panoramic radiographs. M etallic
discarded for lack of answ ers to questions 1, or 2, foreign bodies were found in the nasal fossa and
or both. A nother 18 w ere rejected because the the orbital regions. M ucous retention phenom ena
observer noted that the periapical intraoral films in the maxillary antrum w ere classified as the

Table 1 D etection of lesio n s in c lin ic a lly asym p to m a tic p a tie nts by

in tra o ra l and p a n ora m ic rad io g ra p hy.
Unacceptable sets 61
Incomplete reports 29
Inadequate intraoral survey 18
Inadequate panoramic 14
Acceptable sets 3,059
No additional conditions noted on panoram ic film 2,897
No conditions noted on intraoral film s 95
W ith conditions noted on intraoral film s 2,802
A dditional conditions noted on panoram ic film 162
No conditions noted on intraoral film s 3
W ith conditions noted on intraoral film s 159
Total radiographic sets examined 3,120

W hite Weissman: DISCERNMENT OF LESIONS BY INTRAORAL, PANORAMIC RADIOGRAPHY 1119

Table 2 Additional structures and lesions. The finding o f 3 possibly treatable cases (im
Structures or lesions No. pacted fourth molars) o f 3,059 examined (0.1%)
Submandibular salivary gland defect 3
Foreign body (nose, orbit) 2 does not seem reasonably significant, as these can
Mucous retention phenomenon in maxillary antrum 78 be considered to be elective surgery, unless we
Calcified stylohyoid ligament 53
Osteosclerosis 9 wish to prescribe mandatory removal for all im
Osteoma 1
Ectopic calcification 5 pacted structures. Evaluation o f each o f the other
Lymph node calcification 8
Impacted fourth molar________________________________ 3_ cases determined that none o f the 13 ectopic and
lymph node calcifications was symptomatic and
to this date have not required treatment. This
most numerous category and were counted just
finding is reinforced by the literature,13 which
once, whether single or bilaterally evident. Cal
indicates that such lesions generally are benign
cified stylohyoid ligaments also were noted once
and rarely require further attention once dis
even though bilateral and were distinguished from
covered. All the other conditions also would be
the styloid process if they extended below the
expected to await the development of symptoms
superior third o f the mandibular ramus. The os before further examination or interference would
teoma occurred on the inferior border of the body be warranted.
o f the mandible and, even though the patient was All asymptomatic lesions that required im
aware o f its presence, it was included in the study
mediate investigation or attention were found to
as an asymptomatic lesion. The same was true of
be initially evident on the intraoral periapical sur
the category o f lymph node calcification, almost
vey. Although we recognize the possibility that
all o f which were discovered in the area o f the
one might detect clinically occult pathologic con
mandibular angle and hyoid bone. M ost o f the ditions with a panoramic examination only, our
osteoscleroses were found within the body o f the observation was that the frequency o f such an
mandible; one was in the maxilla. O f the impacted occurrence may be significantly less than when
fourth molars, two were in the mandible and one using intraoral films. On multiple occasions, le
in the most posterior portion of the maxilla. Thus,
sions visible on periapical films could not be ver
162 o f 3,059 cases (5.3%) showed evidence of ified on the panoramic films. It seems to us, there
unusual conditions not seen on the periapical fore, that the rationale for the general use o f the
radiographs. panoramic radiograph in the clinically negative
We do not suggest that these data bear any patient seeking general care cannot be based on
direct relationship to the actual frequencies of
the expectation o f detection o f a high incidence of
occurrence for the various lesions indicated. The pathologic conditions that would not be revealed
population reported here is neither random nor by conventional intraoral periapical radiographs.
representative because all patients with known or
Although the rate o f detection o f pathologic
suspected pathologic conditions, and the fully conditions not observed on intraoral radiographs
edentulous patients, have been excluded. Fur is minimal, a panoramic radiograph of the patient
thermore, the 2,802 positive intraoral sets, in seeking general dental care has many other uses.
which no additional information was detected by In routine use of such films at this institution, we
panoramic radiograph, were not tabulated as to have found them to be most valuable as a teaching
type of lesion or anomaly. instrument for both students and patients. The
visual association of dental anatomy and osteol
ogy with the panoramic view helps the student to
Discussion understand more clearly the anatomic relation
ships o f this region. Similarly, patients may be
In this study we have examined sets o f panoramic made to appreciate more readily their dental
and intraoral radiographs to determine the addi needs.
tional incidence o f pathologic conditions detected A definite benefit to the practitioner of this
only on the panoramic radiograph among a popu radiographic procedure is the acquisition o f nega
lation of patients seeking general dental care. This tive information: that each patient is, in fact, free
was initiated by a concern that the general dentist of intraosseous pathologic conditions beyond the
may have been failing to detect orofacial scope of the intraoral survey. The degree o f value
pathologic conditions in his patients by not o f such assurance must be individually evaluated
routinely utilizing the broad coverage o f this re by each dentist. Certainly in instances in which
gion afforded by the panoramic examination. pathologic conditions are known or suspected be

1120 JADA, Vol. 95, December 1977

yond the coverage o f periapical films, the use of
panoramic radiography is highly recommended.
Summary
Furthermore, its use in studies for pre- and post
treatment views o f surgical procedures that re Although we believe that there are many specific
quire healing assessment, such as cysts, os indications for the use o f panoramic radiography,
teomyelitis, and so forth, is most helpful. Radiog its routine use for patients seeking general dental
raphy for cases o f trismus or other mandibular care cannot be justified on the basis o f an expecta
immobilization, and the intractable patient, is a tion o f detection o f a high incidence o f pathologic
most advantageous feature. Recognition o f vari conditions not visible on a periapical survey. In
ous pathologic entities where broad comparison view o f this and because the radiation dose is
o f contralateral structures is essential, is easier reasonably low in comparison with an intraoral
with the panoramic view. Scleroderma, sickle cell survey, the panoramic examination is most ap
anemia, fibrous dysplasia, and hyperparathy propriate as an adjunct to periapical radiographs
roidism as well as numerous other pathologic when there are specific indications. This decision
conditions are enhanced in understanding by to use the panoramic examination should be made
virtue o f such bilateral demonstration o f trabec- by each practitioner depending on the needs o f his
ulation and cortication. Panoramic radiographs practice.
provide a valuable screening service for edentu
lous patients.
The application of panoramic radiography to "Siem en s Co., Iselin, NJ 08830.
fls a a c M asel Co., 30 2 1 Darnell Rd, Philadelphia, 19 15 4 .
general asymptomatic dental care raises the ques
t S . S . White, Three Parkway, Philadelphia, 19 10 2 .
tion o f how reasonable it is to expose patients for General Electric Co., M edical System s Div., M ilwaukee, 5 3 2 0 1.
only a slight probability o f detection o f urgent new 11 E ast man Kodak Co., Roch ester, NY 14650.
information. The answer depends equally on the " A d a Products, Inc., PO B ox 17 50 9 , M ilwaukee, 5 3 2 17 .

amount o f the additional radiation burden to be

incurred as on the extent of the diagnostic benefit 1. Paatero, Y.V. Use of m obile so u rce of light in radiography.
that may be derived. The literature14 does not Acta Radiol 2 9 :2 2 1 Ju ly 1948.
2. Hudson, J.W .; Kumpala, J.W .; and Dickson, G. A panoram ic
provide us with any absolute measurement of X-ray dental machine. US Armed F o rces Med J 8:46 J a n 19 57.
dose levels for panoramic exposure that can 3. Kite, O.W., and others. Radiation and im age distortion in the
directly assess the radiation hazard. Van Aken Pan orex X-ray unit. Oral Su rg 1 5 :1 2 0 1 Oct 1962.
4. Lund, T.M., and Manson-Hing, L.R. A study of the focal
and van der Linden15 have calculated that the troughs of three panoram ic dental X-ray m achines. Oral Surg
integral absorbed dose for a single orthopan 39:647 April 19 75.
tomograph panoramic survey, at 280 mAs and 69 5. Laney, W.R., and Tolm an, D.E. The u se of p anoram ic radiog
raphy in the m edical center. Oral Su rg 26:465 Oct 1968.
kVp, is 109 gram-rads. (The term integral ab 6. Kraske, L.M., and Mazzerella, M.A. Evaluation of a panoram ic
sorbed d ose refers to the total amount o f ab dental X-ray machine. Dent P ro g re ss 1 :3 3 April 19 6 1.
sorbed radiation and is calibrated in gram-rads 7. Hansen, B.F., and Jo h a n sen , J.R . Oral roen tgen ologic find
ings in a Norwegian urban population. Oral Su rg 4 1:2 6 1 Feb 1976.
where 1 gram-rad equals the absorption o f 1 rad by 8. Ainamo, J ., and Tam m isalo, E.H. T he Orthopantom ogram in
1 gram of tissue. It is equivalent to 100 ergs.) quantitative assessm en t of margi nal bone loss. Suom Ham m aslaak
Preliminary experimental results o f our own pre Toim 6 3 :13 2 Ja n 1967.
9. Graber, T.M. Panoram ic radiography in orthodontic d iag
sent research suggest to us that their15 calculation nosis. Am J Orthod 53:799 Nov 1967.
is reasonably accurate. For comparison, they 10 . Mitchell, L.D. Panoram ic roentgenography. JAD A 66 :777
have further reported that the integral absorbed Ju n e 1963.
1 1 . Ohba, T., and Katayam a, H. C om parison of orthopantom og
dose from a 16-film intraoral periapical survey raphy with conventional periapical dental radiography. Oral Surg
(42-cm focal spot-skin distance, 6-cm beam diam 34 :52 4 Sept 1972.
eter) at 15.5 mAs and 60-75 kVp, is 700 gram- 12 . B ushong, S.C ., and others. Panoram ic dental radiography
for m ass screen in g. Health P h ys 25:489 Nov 19 7 3 .
rads. Although it thus appears that the dose level 1 3 . Stafne, E.C., and Gibilisco, J.A . Oral roen tgen ograp hic d iag
for panoramic radiography might be but 15% of nosis, ed 4. Philadelphia, W. B. Sau n d ers, 19 7 5 , p 13 8 .
14 . Manson-Hing, L.R. P anoram ic dental radiography. S p rin g
that o f the intraoral survey, we cannot dismiss it
field, III, Charles C Thom as, 19 76, p 15 2 .
as being without any biologic consequence. Pru 15 . Van Aken, J ., and van der Linden, L.W .J. The integral ab
dence dictates we ascribe to the linear non sorbed d o se in conventional and panoram ic com plete month
threshold extrapolation hypothesis used by the exam inations. Oral Surg 22:6 03 Nov 1966.
16 . T he effects on populations of ex p o su re to low levels of ioniz
U S National Radiation Council for setting stan ing radiation. Report of the A dvisory Com m ittee on the Biological
dards, that no exposure is without concomitant E ffects of Ionizing Radiation. W ashington, DC, National A cadem y
risk.16 of S c ie n c e s, National R esearch Council, 19 7 2 .

WhiteWeissman: DISCERNMENT OF LESIONS BY INTRAORAL, PANORAMIC RADIOGRAPHY 1121