ANAHTAR KELİMELERDens in dente, Füzyon, Süpernumere diş

ÖZET

KEYWORDSDens in dente, Fusion, Supernumerary teeth

ABSTRACT

Dens in dente ve füzyon iyi bilinen ve iyi tanımlan-

mış dental anomaliler olmasına rağmen süpernume-

re dişlerde nadiren görülürler. Füzyon özellikle mak-

siller anterior dişlerde oluştuğunda estetik problem

yaratır. Bu makalede, süpernumere iki anterior dişte

nadir görünen dens in dente ve füzyonun birlikte

görüldüğü bir olgu rapor edilmiştir.

Although dens in dente and fusion are well-known

and well-established dental anomalies, they are rarely

seen in supernumerary teeth. Fusion has a negati-

ve impact on esthetics especially when it occurs in

maxillary anterior teeth. This paper reports an unu-

sual case of dens in dente and fusion occurring in two

anterior supernumerary teeth and their treatment.

Hacettepe Dişhekimliği Fakültesi DergisiCilt: 30, Sayı: 3, Sayfa: 54-59, 2006

Dens in Dente and Fusion Occuring in Two Supernumerary Teeth: Report of An

Unusual Case

İki Süpernümere Dişte Görülen Dens in Dente ve Füzyon: Olgu Raporu

*Serdar UYSAL DDS, PhD, **Ayşegül NAZİKOĞLU MD, *Nihal AVCU DDS, PhD,**Sevda MÜFTÜOĞLU MD

*Hacettepe University Faculty of Dentistry, Department of Oral Diagnosis and Radiology**Hacettepe University Faculty of Medicine, Department of Histology

OLGU RAPORU (Case Report)

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INTRODUCTION

Dental anomalies are associated with both the primary and the permanent dentitions and can affect either the morphology or the number of teeth. Although these anomalies occur inf-requently, they can cause esthetic, spacing and periodontal problems1.

Dens invaginatus is a rare malformation of tooth showing a wide spectrum of morphologi-cal variations2,3,4,5. Teeth in both maxillary and mandibular arches may be affected, but the per-manent maxillary lateral incisors are the most commonly involved teeth5,6,7,8. The invaginati-on ranges from a slight pitting to an anomaly occupying most of the crown and root9. Tooth crowns as well as roots may exhibit variations in size and form2,3,4,5. Cases of dental invaginations in supernumerary tooth have been presented2. Studies have revealed an incidence ranging from 0.25% to 10%10.

The affected tooth radiographically shows an infolding of enamel and dentine which may ex-tend deep into the pulp cavity and into the root and sometimes even reach the root apex2,3,4,5. Radiographic examination shows a radiopaque invagination equal to the enamel density. In ge-neral, the radiographic evaluation shows a pe-riapical lesion of the affected teeth5. The pulp may remain vital if the invagination extends from the crown to the periradicular tissue and has no communication with the root canal system6. The treatment of a tooth with dens invaginatus ranges from conservative restorative procedures to non-surgical root canal therapy, surgery or extraction6, 9.

Tooth fusion is defined as a union between the dentine and/or enamel of two or more sepa-rate developing teeth. The fusion may be either partial or total depending on the stage of tooth development at the time of the union. Although the aetiology of this anomaly is still unknown, the influence of pressure or physical forces pro-ducing close contact between two developing te-eth is the probable cause1,8,11,12. Fusion may be partial, including only the tooth crowns, or total

involving tooth crowns and roots11. Fusion asso-ciated with a supernumerary tooth such as mesi-odens 13 and various cases14,15,16,17 has been desc-ribed in the literature. Radiographic examination is necessary to obtain the correct diagnosis18. Se-veral treatment methods have been described in the literature with respect to the different types and morphologic variations of fused teeth11.

This report describes a rare case of fusion of two supernumerary teeth and dens in dente of a supernumerary tooth.

CASE REPORT

A 20 year-old male (Ş.A.) was referred to the Oral Diagnosis and Radiology Clinics with a chi-ef complaint of “bad looking teeth”. Medical and dental histories were non-contributory and there was no previous trauma to the teeth or jaws.

Clinical evaluation indicated that the pati-ent was a healthy man with no other physical abnormalities. Intraoral examination revealed the maxillary right and left central incisors were positioned vestibularly and two ectopic super-numerary teeth were located in the usual ana-tomic position of the permanent central incisors (Fig 1). There were developmental grooves on the facial and palatal surfaces of the left super-numerary tooth. The lateral incisors had normal shapes and positions. The canines were missing bilaterally and we learned the history of extracti-on for both of them. Percussion, palpation sensi-tivity, and mobility tests were normal. There was no significant periodontal pocketing and there was a negative response to pulp testing on the right supernumerary tooth. The left supernu-merary tooth showed no significant periodontal pocketing but was sensitive to percussion and gave a negative response to electrical pulp test. Radiographic examinations (panoramic and pe-riapical) showed right supernumerary tooth had a shortened, wide atypical root and was diagno-sed as fusion of two supernumerary teeth (Fig 2). The left supernumerary tooth had dens in dente view and irregular diffuse periapical radiolucency was diagnosed as chronic apical abcess (Fig 3).

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Upon consultations with the Departments of Prosthetic Dentistry and Orthodontics, the determined treatment option was orthodontic alignment of permanent central incisors fol-lowing extraction of the fused and invaginated tooth. This treatment option was discussed with the patient; however, he preferred extraction of the supernumerary, invaginated tooth, central incisors and a fixed prosthetic restoration to be done.

After extractions teeth were examined histo-logically. Ectopic central incisors were in normal histologic pattern and nothing pathologic has been seen. Left supernumerary tooth diagnosed as dens in dente histologically.

HISTOLOGICAL EXAMINATION

Light microscopy

Two atipic meziodens teeth and two ectopic located teeth from the same patient were rapid-ly fixed in %10 phoshate buffered formalin, they were decalcified in De Castro solution, then they were dehydrated through graded alcohols and processed for routine light microscopy. Speci-mens embedded in paraffin blocks and 5 µm se-ctions were cut and stained by haematoxylin and eosin (H&E), Verhoeff, Schmorl’s bone staining method and methylen blue according to standard protocol. And observed on Olympus BH2 mic-roscope.

RESULTS

In sections from left supernumerary teeth, light microscopic observations showed a patho-logical structure considering dens in dente. The-re was pathologic immature tooth organization appeared in the pulp of main tooth. Immature pathologic tooth existing pulp, irregular dentin tubules and enamel, and these structures were appeared to locate transversally in the root re-gion of the main tooth. Examination of this im-mature pathologic tooth revealed prominently abnormal histological structure with its irregular dentin tubules and pulp (Fig 4). As indicated by

FIGURE 1

Intraoral view of the patient.

FIGURE 2

Periapical radiograph of the right supernumerary tooth.

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FIGURE 3

Periapical radiograph of the left supernumerary tooth.

different special staining methods, pulp of this immature tooth composed of a calcified conne-ctive tissue. It was interesting to observe partial-ly calcified, bone like tissue in this pathological structure’s pulp. Surrounding this pathological immature tooth, the main tooth existed a normal histological structure by pulp containing loose connective tissue; odontoblasts located closed to dentin, regular dentin tubules and well organized enamel.

Similarly; light microscopic examination of right supernumerary tooth revealed an abnormal histological structure with wide atypic root and fusion of two teeth. The fused immature tooth was near the root of the main tooth and out of the cementum that was surrounded by dentin. We observed a bone-like structure in its pulp as well.

We obtained good results by Schmorl’s sta-ining which is recomended for any decalcified bone tissue. This is the one of the staining met-hods for decalcified bone parafine sections deve-loped by Schmorl et al19. This staining provide us with better option to decide more accurate and satisfactory observation indicating the blue stai-ned osteoblasts in calcified collagen fibers.

Two ectopic located central incisors were ob-served to have normal histological structure.

DISCUSSION

In this case, fusion of two supernumerary te-eth and dens in dente of a supernumerary tooth has been presented. Synonyms of dens invagi-natus are; dens in dente, invaginated odontoma, dilated gestand odontoma, dilated composite odontoma, tooth inclusion and dentoid in dente. Although over the last decades several theories have been proposed to explain the etiology of this malformation, it is controversial and remains unclear2, 7. The clinical morphology of the crown of the affected tooth may range from being nor-mal to presenting an unusual form depending on the size of the invagination. In some cases, the labiolingual diameter of the crown can be greater

FIGURE 4

The pulp of the pathologic immature tooth. Partially calcified bone like tissue (arrows) that is rich in collagen. Dentin of supernumerary main tooth (double arrow) (Haematoxylin-

eosin X10)

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than normal as in this case. In most severe forms the tooth usually presents a conical crown5. In most cases, dens invaginatus is detected by chan-ce during radiographic examination. Clinically, unusual crown morphology or a deep foramina coecum may be important sign. If one tooth is affected, contra-lateral tooth should also be exa-mined2. A detailed radiographic examination is therefore essential if the anomaly is suspected. It is also advisable to take radiographs from vari-ous angles to provide a better understanding of the extensions of the anomaly5. In our case; the tooth had an atypic form, sensitive to percussi-on and gave negative response to electrical pulp testing. After intraoral and radiographic exami-nations, maxillary left supernumerary tooth was diagnosed as having dense in dente and chronic apical abcess.

Dental literature shows a wide range of treat-ment choices for invaginated teeth2,3,5,6,9. When pulpal or periapical pathosis develops, modifi-cations to the treatment approach are required. Function and esthetics, type of invagination, configuration of the root canal system, prosthe-tic requirements, time constraints, economic and psychological considerations are determinant factors for the choice of treatment5. Extraction is indicated as a last choice of treatment5 only in teeth with severe anatomical irregularities and in supernumerary tooth that can not be treated non-surgically or with apical surgery2,5. However, our patient did not accept the treatment choices and he preferred extraction along with prosthe-tic rehabilitation.

Fusion is defined as the joining of two develo-ping tooth germ resulting in a single large tooth structure13. Clinically anomaly may result in est-hetic problems and thus may require some kind of endodontic, restorative, surgical and/or ort-hodontic treatment11. Dental literature presents various cases that show fusion of the permanent tooth with supernumerary teeth14,16,17. The most common supernumerary tooth is the “mesio-dens” located between maxillary central incisors that usually has the form of a cone-shape crown

with a short root13. Clinically, it may be difficult to differentiate fusion when supernumerary too-th is fused with a permanent tooth. However, dif-ferentiation may not be critically important while accomplishing treatment13,20,21. It is obvious that it is more difficult when a fusion developed with two supernumerary teeth.

Most authors agree that there seems to be no sex difference and location of the malformation. It is usually restricted to the canine-incisor region. The frequency distribution appears to be 0.5% in the primary dentition and 0.1% percent in the permanent dentition12,18. Structurally, there is always a union between the dentin of the fused tooth which can vary from partial to complete fusion of both roots and crowns. Consequently, pulp chambers may be separated or common to both teeth18. A radiographic examination is ne-cessary to obtain a correct diagnosis. In our case a short root and only one root canal was clearly visible on the radiograph. Because of the crown form and short root, we diagnosed it as fusion of the two supernumerary teeth.

Case reports on fusion of teeth appear frequently in dental literature14,15,16,17,22 and several treatment methods have been described with respect to the different types and morphological variations of fused teeth11. Separation and removal of the least desirable portion is indicated as long as there is a satisfactory crown-to-root ratio for the retained part of the tooth. Depending on the situation, necessary endodontic treatment and prosthetic restoration could be done successfully. Some authors believe that this type of solution is more desirable than extraction and prosthetic restoration12.

Every case has its own condition and treat-ment. Scientific criterion must be used for cho-osing treatment method along with the patients’ desires. As in this case, extraction and prosthetic restoration were the chosen treatment option due to the patient’s preference.

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CORRESPONDING ADDRESS

Serdar UYSAL DDS, PhDHacettepeUniversityFacultyofDentistry,DepartmentofOralDiagnosisandRadiology,06100Ankara/TURKEY

Tel: +90 312 305 22 09 Fax: +90 312 305 42 21 e-mail: suysal@hacettepe.edu.tr