Indian Journal of Dental Research

: 2009  |  Volume : 20  |  Issue : 2  |  Page : 243--245

Endodontic treatment of a periradicular lesion on an invaginated type III mandibular lateral incisor

B Carvalho-Sousa, F Almeida-Gomes, LF Gominho, DS Albuquerque 
 Department of Endodontics, University of Pernambuco, Pernambuco, Brazil

Correspondence Address:
B Carvalho-Sousa
Department of Endodontics, University of Pernambuco, Pernambuco


Dens invaginatus (DI), commonly known as dens in dente, is a developmental malformation of teeth that most commonly affects permanent maxillary incisor teeth. DI can present in a variety of forms, knowledge of which can usefully help in endodontic diagnosis and treatment. This article reports on an unusual case of DI type III with a periradicular lesion in a mandibular lateral incisor. Non-surgical endodontic treatment was performed and resolution of the periradicular lesion was observed at 1 year follow-up. Clinical considerations and treatment are discussed and reported.

How to cite this article:
Carvalho-Sousa B, Almeida-Gomes F, Gominho L F, Albuquerque D S. Endodontic treatment of a periradicular lesion on an invaginated type III mandibular lateral incisor.Indian J Dent Res 2009;20:243-245

How to cite this URL:
Carvalho-Sousa B, Almeida-Gomes F, Gominho L F, Albuquerque D S. Endodontic treatment of a periradicular lesion on an invaginated type III mandibular lateral incisor. Indian J Dent Res [serial online] 2009 [cited 2022 Jun 27 ];20:243-245
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Full Text

Dens invaginatus (DI), commonly known as dens in dente, is a relatively rare developmental anomaly resulting from invagination of the root before calcification has occurred. [1] Fusion is defined as the union of the dentin and/or enamel of two or more separate developing teeth and may include the root canal system. An invaginated tooth may be observed when this fusion includes the root canal system. [2] Other theories indicate infection, trauma and genetics as possible contributing factors. [3] The reported occurrence ranges from 0.04 to 10% and the teeth most often affected are the maxillary lateral incisors. [4] Dens invagination has been classified into three categories according to the depth of penetration and communication with the periapical tissue or periodontal ligament. Type I is characterized by invagination confined within the crown, only extending to the cementoenamel junction (CEJ). Type II is characterized by invagination that extends apically beyond the CEJ into the root but ending in a blind sac, without reaching the periodontal ligament or periapical tissue. Of particular interest in this classification is type III, in which the invagination extends apically through the root and exhibits a second foramen into the lateral periodontal ligament or periodontal tissue. [5] Type III invagination can provide a pathway for bacteria to penetrate the periodontal ligament area, with subsequent pathological periradicular involvement. [6] The complex anatomy of type III invagination is a factor that often makes treatment more difficult. Several recommended treatments have been reported in the literature, including extraction, endodontic surgery, intentional replantation and non-surgical root canal therapy. [2] This article describes resolution of a periradicular lesion following endodontic treatment of a type III invagination in a mandibular lateral incisor.

 Case Report

A 30-year-old male patient with non-contributory medical history was referred for endodontic therapy. Clinical examination revealed a sinus tract in the buccal area next to the affected incisor and a mandibular lateral incisor of unusual diameter. The patient's dental arch contained the normal number of teeth. Radiographic examination showed that the right permanent mandibular lateral incisor had a DI type III and a periradicular lesion [Figure 1]. The pulp vitality test was negative and a clinical diagnosis of pulp necrosis with periradicular lesion was made. The incisor was anesthetized and isolated and a coronal access was prepared. Two root canal openings were located. The canals were cleaned and the root canal lengths were established using an electronic apex locator, model Root ZX (J. Morita, Kyoto, Japan). The canals were shaped in a crown-down method using Gates Glidden drills and K-files (Maillefer, Ballaigues, Switzerland). Sodium hypochlorite (2.5%) and ethylenediamminetetraacetic acid (17%) solutions were used as irrigants. After cleaning and shaping, calcium hydroxide in a polyethylene glycol vehicle was used for 6 months [Figure 2]. The canals were filled according to Tagger's technique [7] using gutta-percha points and a root canal sealer [Figure 3]. At 1 year follow-up, the tooth was asymptomatic and radiographic findings suggested resolution of the periradicular lesion [Figure 4]. However, complete healing is not yet evident and long-term clinical follow-up must be carried out in this case.


The mandibular occurrence of DI is a rare situation. [8] A review of the English literature only identified three cases involving four mandibular incisors. [9] One case report described a mandibular lateral incisor with DI type III, necrotic pulp and apical periodontitis. [10] In Sweden, a retrospective study of a 30-year period found 131 teeth with DI in 91 patients. The authors did not report any mandibular DI among these patients. [11]

Root canal treatment of teeth with type III DI extending to the apical area in combination with a large periradicular lesion can cause difficulties because of the unpredictable shape of the internal anatomy. If no entrance to the invagination can be detected and there are no signs of pulp or periapical pathology, no treatment is required. However, if signs and symptoms of pulp or periradicular pathology are present, treatment is necessary. Non-surgical endodontic treatment should be attempted first. Regardless of the size of the periradicular lesion, surgical treatment is the second option to be used only after non-surgical endodontic treatment has failed. The success of this and other cases indicates that the size of the periradicular lesion does not dictate the treatment procedure or influence the treatment outcomes of non-surgical root canal therapy. [12]

One of the reasons for describing this case was the unusual root morphology and the size of the associated periradicular lesion.

The large and irregular volume of the root canal system makes proper shaping and cleaning difficult. Another difficulty in this case was to establish the working length. An apex locator and radiographs were used to establish the correct apical instrumentation and obturation limit.

Calcium hydroxide has been used to disinfect root canals [13] and induce apical barrier formation. [14] It has also been used to control exudation in the canal. [15]

In the present case, calcium hydroxide in a polyethylene glycol vehicle was used for 6 months to achieve disinfection, to dry the canal and to induce formation of an apical barrier. For root canal filling, thermoplastic methods seemed preferable to other techniques.

This case shows that it is possible to achieve resolution of a large periradicular lesion in a tooth with severe type III DI using endodontic treatment. However, long-term clinical follow-up will be continued with this case because complete healing has not yet been seen.


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