© Borgis - Nowa Stomatologia 3/2003, s. 107-110
L.J. Pypeć, A. Bruzda-Zwiech
Dens invaginatus as endodontic problem – case report*
Department of Paediatric Dentistry, Institute of Dentistry,
Medical University of Lodz
The developmental anomaly known as dens in dente, dens invaginatus, dens Saltersi occurs as an indentation of hard tissues of the tooth into the pulp chamber or into the root canal (1, 2). This condition is most probably caused by an invagination of the inner enamel epithelium into the dental papilla prior to calcification (3, 4, 5). Pindborg, except of dislocation of the enamel organ relation to the dental papilla, mentions several other hypotheses, which have been put forward with regard to the aetiology and pathogenesis of the invaginations:
– abnormal pressure from the surrounding tissue during tooth formation,
– defects in the enamel organ occupied by connective tissue which, as tooth formation progresses, retard local development (6).
Dens invaginatus is a fairly common condition in maxillary lateral incisors, but any type of tooth may be seat of an invagination (4, 5, 6, 9, 10). The anomaly is very rare in the mandible, and only few cases were reported among primary dentition (7). Supernumerary teeth quite often present invaginations (5, 8). The prevalence of dens invaginatus ranges from 0,25-6,8%. Poyton and Morgan (11) stated the prevalence of 0,25%, Amos (12) – 5,1%, and Backman (13) reported the prevalence of this anomaly of 6,8%. The opening to the invagination is located on the palatal surface of the tooth, under the dental cusp, in normally shaped teeth and on the top of incisor´s edge in peg-shape teeth (10). Very rarely a radicular invagination is observed. The invaginations may vary from slightly accentuated cingulum (foramen coecum) to deep infolding reaching the apical foramen (6). Classifications of this anomaly include: extent of the invagination (shallow, deep, deep with deformation of the crown), localization (crown, root), and defects in the bottom of the invagination (1, 6). The deeper the invagination the weaker mineralization of enamel and dentine in the bottom of the invagination is. That may cause a direct communication between the bottom of the invagination and the pulp (6, 14). The communication may consist of one or more small canal. In some cases of „dens in dente” the enamel lining the invagination is almost absent over a small area at the deepest part. The unprotected dentine may give bacteria access to the underlying pulp (4, 15). Food debris and microorganisms may become packed into the defect, leading to early carious destruction and to pulp pathosis (3, 5, 6). Because of this risk, the opening of the defect should be sealed as soon as possible (16). Prophylactic invagination treatment helps to avoid serious periapical complication that could influence the outcome of endodontic treatment (16). Therapeutic treatment of pulp and periapical pathosis in dentes invaginatus, have better prognosis in teeth with the completed development of the root (1). Endodontic treatment can be successful even in the cases with very deep infolding, which extends to 1/3 apical part of root (17, 18).
A 9-year-old girl with non-contributory medical history was referred to Department of Paediatric Dentistry Medical University of Lodz for the presence of symptoms of apical periodontitis (periapical pathosis) of the maxillary lateral incisor. Gathered anamnesis revealed spontaneous pain and swelling related to the maxillary right incisor, which were noticed a month prior to admission. Clinical examinations of the oral cavity revealed the presence of fistula in the region of the maxillary lateral incisor. The tooth 12 was tender to percussion, non-responding to vitality testing. An unsound restoration was present on the palatal surface of the tooth in the region of the foramen coecum. The X-ray showed the developmental anomaly known as dens in dente. An enlargement of outlines of root, and deep infolding of the dental hard tissue extending to 1/3 apical part of the root was seen (fig. 1). To institute the treatment a panoramic radiograph was taken, which confirmed that only the maxillary lateral incisor was seat of an invagination (fig. 2). The analysis of the OPG brought also a suspicion of the presence of another anomaly in the region of the germ of the left lower canine, which was excluded after a mandibulary occlusal radiograph was taken. Even though successful endodontic treatment of this case was doubtful it was decided to carry out a canal root therapy, taking into consideration the patient´s occlusion and her young age. After the pulp access was prepared, the chemo-mechanical cleaning and shaping of the root canal was initiated. The first step was to go through the bottom of the invagination, and second – to prepare the main canal to the working length (fig. 3, fig. 4). The length of the root canal was determined with apex locator (Root XZ), and confirmed by taking RVG with a reamer placed inside. Calcium hydroxide (Calcicur) was placed into the root canal. The Ca(OH)2 dressing was initially changed after 1 month, and then after 3-month period. The intra-oral examination carried out after 3-month period reviled no mucosal changes of the alveolar process (no swelling), disappearance of the fistula and tenderness to percussion. The RVG taken after 6 months showed the presence of the mineralized barrier in the apical part of the tooth. Finally, the root canal was filled with gutta percha cones and AH plus sealer using the lateral condensation technique. Additional obturation with the sealer of the recesses in the deformed part of the canal extending to 1/2 length of the root was also obtained (fig. 5). At 12 months follow up the tooth was found to be asymptomatic. Clinical and radiological follow-ups of the tooth studied will be continued every 6 months.
Fig.1. The X-ray of the right lateral maxillary incisor showed the developmental anomaly known as dens in dente. An enlargement of outlines of root, deep invagination of the dental hard tissue extending to 1/3 apical part of the root can be noticed.
Fig. 2. The panoramic radiograph confirmed that only the maxillary lateral incisor was seat of an invagination.
Fig.3. The first step of RCT was to go through the bottom of the invagination.
Fig.4. The main canal is prepared to the working length.
Fig. 5. The X-ray shows the root canal of the maxillary right lateral incisor filled with gutta percha cones and AH plus as sealer using the lateral condensation technique. The additional filling with the sealer of recesses in deformed part of the canal extending to 1/2 length of the root was obtained.
Some authors found that the incidence of dens invaginatus is higher in young persons. Teeth with invaginations are in the majority observed in children between ages of 7 and 14 years. The decrease of cases with this anomaly in older population might be associated with early loss of these teeth (8). Sometimes, in planning of the treatment of malocclusions, teeth with invaginations are recommended to be extracted, because of difficulties with performing of endodontic therapy and doubtful effect of such treatment (1, 10). Rot canal therapy may present severe problems because of complex anatomy of those teeth (4, 18). Generally, it is said that dens invaginatus is more susceptible to caries, what leads to its early destruction by caries and pulp pathology (3, 14). Some reports suggested that such teeth are prone to pulp infection and periapical lesion in the absence of caries or trauma (6, 14, 15). The greater the invagination, the higher the risk of pulp necrosis is. The lack of hard tissue in the bottom of invagination gives one or more fine routes to the dental pulp, so that the dental pulp is likely to be infected and become necrotic (6, 14). On the other hand, in cases with well-mineralized bottom of the invagination pulp pathosis might occur because of caries penetration into the invagination space (3, 5).
In the described case it is difficult to consider what the primary reason of periapical infection was. The presence of a restoration in the region of the foramen coecum might suggest that the tooth has been accompanied by caries. Anyway, the opening tot he invagination might have been sealed for prevention of caries. The normal shape of the crown, almost completed development of the root and the lack of possibility of closing the gap by orthodontic treatment if the tooth with invagination was extracted, were factors for conservative treatment in this case. The case presented showed that endodontic treatment can be successful even when the deep invagination is observed. Non-surgical successful treatment of teeth with invaginations in children is reported also by other authors (18, 19).
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