J. Nihon Univ. Sch. Dent., Vol.39, No.4, 171-175, 1997

Original

A clinicopathologic study of odontomas: Malaysian findings

Kok Han Ng1 and Chong Huat Siar2

Division of Stomatology1, Institute for Medical Research, Jalan Pahang 50588 Kuala Lumpur, Malaysia

Department of Oral Pathology2, Oral Medicine and Periodontology Faculty of Dentistry, University of Malaya, 50603

Kuala Lumpur, Malaysia

(Received 21 February 1997 and accepted 22 August 1977)

Abstract: This report reviews the clinico-

pathologic characteristics of 104 cases of odontomas diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year

period (1967-1995). The results showed no real predilection in terms of sex (M: F ratio, 1: 1), race (45.2 % Malays, 40.4 % Chinese, 10.6 % Indians and 3.8 % other races) or site (maxilla: mandible ratio, 1: 1.04) distribution. The mean age at presentation was 24.8 years and the age range was 3 - 74 years. There were 102 intraosseous and 2 extraosseous odontomas. Swelling was the most common presenting complaint. The majority of cases (81.9 %) were clinically diagnosed as odontomas. The treatment of choice was surgical enucleation. Compound (43.3 %) and complex (35.5 %) odontomas were the two most common histological types encountered. The present findings correlate favorably with reported studies from other geographic areas.

Key words: human; odontoma; histopathology;

Malaysians.

Introduction Odontomas are malformations of dental tissues (1).

These lesions are usually diagnosed in the second and third decades of life and show an almost even distribution between the sexes (2-12). Clinically, these patients

present with few symptoms and the odontomas are often discovered during routine radiographic examination (4-6). They may occur anywhere in the jaws, showing either a slight predilection for the maxilla or mandible (6-8). Histologically, several types are recognized, the most common being compound (where the dental tissues are arranged in an orderly manner forming many tooth-like structures) and complex (where the dental tissues occur in a disarrayed manner) odontomas (1,5,6). The less commonly encountered variants are the soft tissue or extraosseous odontomas (9,12) and odontomas found in conjunction with calcifying odontogenic cysts (6). Regardless of their histologic forms, odontomas are hamartomatous in nature and recurrences are rare.

Odontomas are well-recognized lesions and serial studies from North America (2,4,6), Australia (8), Chile

(4) and Turkey (7) have delineated their prevalence and clinicopathologic characteristics. However, little is

known of its pattern of occurrence in the Southeast Asian region. In view of this, it seems appropriate to present our analysis of the 29-year record of all diagnosed cases of odontomas from this department and to compare our findings with similar studies from other geographic areas.

Materials and Methods The biopsy records of the Division of Stomatology,

Institute for Medical Research, Kuala Lumpur, were reviewed for the prevalence of odontomas. The basic

criteria used followed definitions and descriptions of odontomas in common use (1-13). One hundred and four cases (including one previously reported (9)) were

found after review. Clinical data with respect to age,

gender, race, location, symptoms and treatment were retrieved from descriptive summaries of biopsy request forms. Radiographs, where available, were also examined to assist in their interpretation. Histologic information was obtained by reviewing hematoxylin and eosin stained sections of all cases without reference to their original reports. Lesions were subclassified as compound, complex, mixed, extraosseous/soft tissue odontomas and odontomas in association with calcifying odontogenic cyst, based on established criteria (1-13). Supernumerary teeth, gestant odontome and true mixed odontogenic tumors (e.g. ameloblastic fibro-odontoma) were excluded from this study.

Results One hundred and four cases of odontomas, including

one case (9) previously reported from this department, were studied. They represented about 2.8 % of all odontogenic cysts and tumors (based on the WHO classification (1)) diagnosed in the Division of Stomatology over a 29-year period (1967-95). Their data were analyzed according to race, gender, age, site distribution, and histologic types (see Table 1). Fifty-one

(49.0 %) of the cases occurred in patients younger than 21 years of age. Of these, 40 (38.5 %) belonged to the 11-20 age group. Twenty-five of the 104 odontomas were asymptomatic. In the remaining 79 cases, the most

Correspondence to Dr. Kok Han Ng, Division of Stomatology, Institute

for Medical Research, Jalan Pahang, 50588 Kuala Lumpur, Malaysia

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Table 1 Race, sex, age, site distribution and histologic types of odontomas in Malaysians

COC - Calcifying odontogenic cyst

Table 2 Demographic characteristics of compound and complex odontomas in Malaysians

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common presenting symptoms in decreasing order of frequency were swelling (74.7 %), pain (19.0 %), discharging sinus (19.0 %), ulcer (13.9 %), erupting odontoma (8.9 %), pericoronitis (1.3 %) and paraesthesia

(1.3 %). The duration of these symptoms ranged from 3 days to 10 years (mean duration, 15.5 months). There were 102 intraosseous and two extraosseous or soft tissue odontomas (one of these cases was previously reported as an extraosseous odontoma occurring in association with a

peripheral odontogenic fibroma (9)). Their site distribution in the jaws is illustrated in Fig.1. Sixty-six of the intraosseous odontomas presented as radiopaque masses, 11 as mixed radiolucent-radiopaque lesions

(examples of these are shown in Figs. 2 and 3). In the remaining 25 cases, their radiographic appearances were unknown. Embedded teeth, namely incisors (10.8 %), canines (8.8 %), third molars (6.9 %), second molars (2.9

%) and supernumerary teeth (0.9 %) were also found in association with these odontomas. There were no underlying radiologic changes in the two cases of soft tissue odontomas studied.

Data on clinical diagnoses were available in 94 cases. Most of these cases (81.9 %) were clinically diagnosed as odontomas. Other less commonly clinically-diagnosed conditions were cementomas (6.4 %), dentigerous cysts

(4.2 %), osteomas (2.1 %), chronic osteomyelitis (2.1 %),

exostoses (1.1 %), epulides (1.1 %) and calcifying odontogenic cysts (1.1 %). The 102 cases of intraosseous odontomas were treated by surgical enucleation while the two soft tissue odontomas were removed by simple excision. Examples of the gross appearances of compound and complex odontomas are shown in Figs. 4 -

Fig. 1 Site distribution of 104 cases of odontomas.

Fig. 3 A complex odontoma occurring as a well-circumscribed (arrowheads) mixed radioluscent/ radiopaque lesion between the right mandibular lateral incisor and canine.

Fig. 2 Radiographic appearance of a compound odontoma

presenting as a radiopaque mass in the right maxillary canine-premolar region (arrowheads).

Fig. 4 Gross appearance of the compound odontoma shown in Fig 2. Note the canine with attached follicle tissue (far right).

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7. Histologic analysis showed that the compound and complex odontomas collectively accounted for about 78.8 % of all odontomas studied (Table 1). A comparison of their demographic characteristics is detailed in Table 2.

Discussion The 104 odontomas reviewed in this study accounted

for about 0.3 % of all specimens submitted in this department (1967-1995). This figure is low compared to the reported prevalence (range, 0.5 % - 1.0 %) from other biopsy service centers (4,8). Furthermore, contrary to

previous findings (2,3,5,6) where odontomas reportedly represent the most common odontogenic tumor diagnosed in the jaws, our records revealed that it ranked second to ameloblastomas (a recent review study showed that 401 cases of ameloblastoma were diagnosed in this department between 1967 and 1991 (14)). It is possible that the number of cases of odontomas diagnosed in this department may not be reflective of its true prevalence in the general population. Probable reasons for this would

be that some of these cases were either submitted to other

pathology laboratories or were not sent for histopatholo-gic examination/confirmation.

Previous studies have demonstrated that odontomas affect a wide age group with most cases being diagnosed in the second and third decades of life (2-8). A similar trend was observed in our study. However, the mean age

(24.8 years) of our patients for all types of odontomas was about 7.2 - 10 years older than those of other studies

(reported range of mean ages, 14.8 - 17.6 years) (2,8,15). Two earlier reports (6,15) have also shown that the mean age of patients with compound odontomas was about 5.5

years younger than patients with complex odontomas. A comparable observation was also made here, with the mean age difference being 4.4 years (Table 2). The

present study also confirmed previous findings that odontomas in general do not exhibit any gender

predilection (7,12). However, the observed gender distribution pertaining separately to the compound and complex odontomas in this series agrees in part with one study (7), but differs from some others (5,7,8). Only two

previous studies had included a racial analysis of their odontoma cases. Kaugars et al. (6) found that a significant percentage of their cases occurred in blacks while Katz (5) observed that the proportion of Caucasian to black patients in his series mirrored the racial

population composition of the sampled metropolitan area of Philadelphia. Our study also showed that the

prevalence of odontomas among the various ethnic groups reflected the local racial population ratio.

The maxillary/mandibular ratio of odontomas in our series (1: 1.04) compares favorably with some studies (range, 1: 1.1 - 1: 1.2) (7,16) but differs from others (1.03: 1 - 1.9: 1) (2,4,6,8,14). The percentage of anteriorly-located odontomas as observed here (38.5%) also falls within the reported range (36.7 % - 59.8%)

(2,4,6,8,15). As with previous studies (5,8), we found that compound odontomas occurred more commonly in the maxilla. However, unlike these studies (5,8), complex odontomas in Malaysians showed a preference for the

Fig. 5 Another example of compound odontoma, also

associated with a partially formed canine.

Fig. 6 The gross appearance of a complex odontoma

presenting as a well-circumscribed mass with a nodular surface (arrows).

Fig. 7 A complex odontoma associated with a supernumerary tooth (S).

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mandible. The reported tendency (8) for these histological types to exhibit a distinct predilection for the anterior and posterior jaw segments, respectively, was likewise noted in this study. The 2 extraosseous odontomas in the current series occurred in the anterior maxilla. While the clinical signs and symptoms of an odontoma are generally considered nonspecific, their radiologic appearances are often fairly distinctive and characteristic such that these lesions are often accurately

diagnosed pre-operatively. A similar observation was also made here. However, the number of odontomas radiographically observed in a dentigerous cyst-like relationship in this study was small (4.2 %) compared

with an earlier report (27.6 %) (6). Odontomas occurring in association with calcifying odontogenic cysts are well

recognized. In this series, a substantial number of these cases (8.7 %) were noted. This is considerably higher than that of Kaugars' study (0.9 %) (9). In another study

(16) of 30 central non-neoplastic calcifying odontogenic cysts, 10 (33.3 %) showed simultaneous occurrence of odontomas. Odontomas are benign, hamartomatous odontogenic lesions and the treatment of choice is conservative surgical enucleation (7,13,17,18). For soft tissue odontomas, simple excision is an adequate treatment (12). All the cases in this series were treated in this same manner. While recurrences are decidedly rare in odontomas, the lack of follow-up records in most of these cases prevented evaluation in this aspect. In summary, this review shows that odontomas are not, by comparison, commonly diagnosed lesions in Malaysia and their demographic as well as clinicopathologic features were generally in close accord with similar series obtained from other geographic areas.

Acknowledgments The authors are grateful to the staff of the Division of

Stomatology for their secretarial and technical assistance; to all the dental specialists for their case contributions that made this study possible; and to Dr. Mak Joon Wah,

Director, Institute for Medical Research, for his

permission to publish this paper.

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