Case Report
Conservative management of Dens Invaginatus with an open apex and vital pulp: A case report
Raul De Alba Valdivia, DDS 1
David Masuoka Ito DDS, PhD 1
Eunice Liset Ascencio Sandoval, DDS 1
Santíago Andaracua Garcia DDS, MS 2
Sugeyn Rodríguez Castillo, DDS 2
Jorge Vera DDS, MS 3
Itzel Athziry Carre Espinoza, DDS 2
Daniela Reyes Pedraza, DDS 2
https://doi.org/10.71347/fr59e2pz
1 Departamento de Estomatología, Universidad Autónoma de Aguascalientes, Mexico
2 Departamento de Endodoncia, Universidad Autónoma de Querétaro, Mexico
3 Advanced Education Program in Endodontics, Department of Periodontics and Endodontics, University at
Buffalo, School of Dental Medicine, USA
Corresponding author:
Jorge Vera DDS, MS, Director of the Advanced Education Program in Endodontics, Department of
Periodontics and Endodontics, University at Buffalo School of Dental Medicine Squire Hall - University at
Buffalo, State University at Buffalo South Campus, 3435 Main St, Buffalo, NY 14215
e-mail: jveraro@yahoo.com.mx
Key words: Dens invaginatus, Immature apex, Cone Beam Computed Tomography (CBCT), Mineral
Trioxide Aggregate (MTA)
Acknowledgements: The authors deny any conflict of interest related to this study.
The patient’s guardian provided informed consent.
Abstract
Background: Dens invaginatus (DI) is a developmental anomaly characterized by a deepening or invagination of the enamel organ into the dental papilla before calcification of dental tissues.
Case description: A 9-year-old female Hispanic patient was referred for evaluation of the upper left central incisor, due to swelling of the attached gingiva. Clinical examination revealed a talon cusp on the palatal surface, a draining sinus tract tracing to the apical area of tooth #9, and radiographically, a possible radiolucency. The cone beam computed tomography (CBCT) scan revealed a hypodense area involving the buccal and mesial cortical bone. The tooth was classified as Oehlers’ Type IIIB dens invaginatus. Root canal treatment of the invagination was performed using an MTA apical plug. At the one-year follow-up examination, the tooth exhibited negative responses to percussion and palpation. CBCT and radiographic examinations showed bone healing and continuous root development, indicating successful treatment outcome.
Conclusion: This case demonstrates that, in select cases of Type IIIB dens invaginatus with an open apex and a vital pulp, conservative treatment limited to the invagination canal can be successful when supported by accurate CBCT evaluation and appropriate material selection.
Introduction
The form, size, and color of human teeth, as well as their eruption timing, show considerable biological variation. However, atypical variations can also be found across different populations. These anomalies are often linked to genetic, environmental, or pathological factors, and may sometimes reflect systemic conditions or syndromes (Hallett, 1953; Oehlers, 1957).
Developmental anomalies of the dentition, though less prevalent than common oral diseases like dental caries and periodontitis, present unique clinical challenges. They may lead to malocclusion, esthetic concerns, and increased susceptibility to other oral health issues (Alani & Bishop, 2008).
Dens invaginatus is one such developmental anomaly, characterized by a deep invagination of the enamel organ into the dental papilla before calcification of dental tissues. It is considered one of the more common dental developmental anomalies, with a reported prevalence in permanent teeth ranging from less than 1% to 10%, depending on the studied population (Alani & Bishop, 2008; Sarnat & Schour, 1941). Bilateral involvement—usually affecting contralateral teeth—has been reported in approximately 43% of cases (Zoya et al., 2015).
The maxillary lateral incisor is most frequently affected, followed by the maxillary central incisor, canines, and premolars (Zoya et al., 2015). Although clinical signs such as grooves or fissures on the lingual surface may raise suspicion, definitive diagnosis typically relies on radiographic examination (Hamasha & Alomari, 2004).
The etiology of dens invaginatus remains uncertain, with several theories proposed. One suggests that pressure within the developing dental arch causes deviation of the enamel organ during growth (Karaca & Toller, 1992). Kronfeld (1934) proposed a failure in the growth of the internal enamel epithelium, while Rushton (1958) suggested that aggressive proliferation of the enamel epithelium into the dental papilla is responsible. Oehlers (cited in Atkinson, 1943) attributed the condition to distortion of the enamel organ during development, resulting in the formation of an enamel-lined invagination terminating at the cingulum or, less commonly, the incisal edge. Other hypotheses include the “twin theory” (fusion of two adjacent tooth germs), trauma during tooth development, local infection, or genetic predisposition (Karaca & Toller, 1992).
The earliest attempt to classify dens invaginatus was by Hallett (1953), who proposed four types based on clinical and radiographic features (Tavano et al., 1994). However, the most widely accepted classification remains that of Oehlers (1957), which divides the anomaly into three main types based on the extent of the invagination:
Type I: Minimal, enamel-lined invagination confined within the crown and not extending beyond the cementoenamel junction (CEJ).
Type II: Enamel-lined invagination extending into the pulp chamber and root canal, without communication with the periodontal ligament.
Type IIIA: Invagination extends through the root and exits laterally into the periodontal ligament via a pseudo-foramen, without communication with the main pulp.
Type IIIB: Invagination extends through the root and communicates with the periodontal ligament at the apical foramen, typically without pulp involvement.
In Type III cases, bacterial contamination of the invaginated tract can lead to localized periodontal inflammation, known as peri-invagination periodontitis (Atkinson, 1943).
Several reports have described the complex management of such cases. Dembinskaite et al. (2018) presented a maxillary lateral incisor (tooth #7) with Oehlers’ Type III invagination and chronic apical periodontitis, involving both the invagination and adjacent vital pulp. Treatment included apical sealing of the invagination with ProRoot MTA, thermoplastic gutta-percha obturation, and the application of Biodentine to dentin adjacent to the pulp. Surgical enucleation confirmed the diagnosis of a cystic lesion.
Kamio et al. (2021) reported a rare case of double dens invaginatus, with both Type IIIA and IIIB features. Despite extensive invagination, the main pulp tissue remained vital. Treatment involved obturation with a warm vertical compaction technique using a zinc oxide and eugenol-based sealer.
Given the anatomical complexity of these cases, successful outcomes depend on careful diagnostic assessment and individualized treatment planning. This report aims to highlight the importance of early and accurate diagnosis and the potential for conservative management in select cases of dens invaginatus.
Case report
A 9-year-old Hispanic female with a non-contributory medical history was referred from the postgraduate pediatric dentistry program to the postgraduate endodontics clinic for clinical and radiographic evaluation of the upper left central incisor (tooth #9), due to localized swelling of the attached gingiva.
Clinical examination revealed a draining sinus tract at the apex of tooth #9 (Figure 1). A talon cusp, partially covered by gingival tissue, was noted on the palatal surface. The tooth responded positively to cold testing with Endo Ice® (Coltene/Whaledent Inc., Cuyahoga Falls, OH, USA) and elicited sensitivity to percussion and palpation. Periodontal probing depths were 2-3-3 mm on the buccal and 3-9-2 mm on the palatal surface.
A gutta-percha point was inserted into the sinus tract, and a periapical radiograph showed that it traced to the termination of the invagination (Figure 2a). To assess potential communication between the invagination and the main canal, a cone beam computed tomography (CBCT) scan was performed using a 5 × 5 cm field of view (FOV), 100 μm voxel size, and an exposure time of 12.048 seconds at 90 kV and 10 mA. Images were analyzed using Romexis software (Planmeca, Helsinki, Finland).
CBCT confirmed the presence of a Type IIIB dens invaginatus, according to Oehlers’ classification. The tooth exhibited Cvek Stage IV root development, with an open apex and more than half of the root length formed (Figures 2b–2c). A hypodense lesion was present in the apical third of the root, with apparent perforation of the buccal cortical plate, likely associated with infection of the invagination (Figures 2d–2e).
Given the positive cold response and incomplete root development, a conservative approach was chosen, limiting treatment to the invaginated canal while preserving the vitality of the main pulp. The treatment plan, along with potential risks and benefits, was explained to the patient's guardians, and both verbal and written informed consent were obtained.
Local anesthesia was administered via buccal infiltration using one carpule of 2% lidocaine (36 mg) with 1:100,000 epinephrine (0.018 mg), followed by rubber dam isolation. Access was gained using a #2 round bur, and the invaginated canal was located. Working length was established with a 25/06 S-One file (Fanta Dental Materials, Shanghai, China) and confirmed radiographically (Figure 3a).
The canal was instrumented using the AF Rotary system (Fanta Dental Materials) up to size 55/04, with irrigation using 20 mL of 1.0% sodium hypochlorite (NaOCl). Calcium hydroxide mixed with physiological saline was placed as intracanal medication, and the access cavity was sealed temporarily with Cavit (3M ESPE, Seefeld, Germany).
At the second visit two weeks later, the tooth remained positive to cold testing and was asymptomatic to percussion and palpation. The sinus tract had healed. After anesthesia using the same protocol, the invagination was re-accessed. Irrigation was performed with 20 mL of 1% NaOCl activated by passive ultrasonic irrigation, followed by 2 mL of 17% EDTA, another 20 mL of 1% NaOCl, and a final rinse with 10 mL of saline to achieve clean dentin and open tubules without erosion.
The canal was dried with sterile paper points, and obturation was completed using ANGELUS HP MTA (Angelus Indústria de Produtos Odontológicos S/A, Londrina, Brazil) with vertical compaction using a NiTi plugger 60/04 (Fanta Dental Materials) (Figure 3b). A layer of Teflon tape was placed over the MTA, and the access was sealed with glass ionomer cement (Vitremer, 3M ESPE). A postoperative radiograph was taken (Figure 3c), and the patient was referred to the pediatric dentistry clinic for definitive coronal restoration.
At the 3- and 6-month follow-ups, the tooth remained asymptomatic. The sinus tract had completely resolved, cold testing remained positive, and periapical radiographs showed progressive healing of the periradicular radiolucency (Figures 3d–3e).
At the 12-month recall, a new CBCT scan revealed further reduction of the apical radiolucency and evidence of bone regeneration in the buccal cortical plate. Root development had progressed to Stage V according to the Cvek classification, indicating near-complete apical closure (Figure 3f).
Discussion
Dens invaginatus presents significant clinical challenges due to its complex and variable internal anatomy (Oehlers, 1957). Prior to tooth eruption, the invagination may contain remnants of the dental papilla or enamel epithelium (Rushton, 1958). Once erupted, the invagination becomes exposed to the oral environment, making it susceptible to bacterial contamination—even in the absence of visible caries—thereby increasing the risk of pulp inflammation, necrosis, or infection (Siqueira et al., 2022).
Management strategies range from conservative, nonsurgical techniques to combined or surgical interventions, depending on the type and extent of the anomaly.
Patel (2010) noted that a normal pulp sensibility response and an intact periapical ligament space usually indicate that the pulp in the main canal remains vital. CBCT imaging is particularly valuable in these cases, as it enables detailed assessment of the invagination and its spatial relationship to the root canal system. Based on this, several authors have advocated for conservative treatment limited to the invagination, provided that it is anatomically separate from the main canal both before and after instrumentation (Bishop & Alani, 2008).
Schwartz and Schindler (1996) highlighted that in Type III dens invaginatus, apical periodontitis may occur even when the pulp tests as vital. In such cases, the inflammatory lesion typically arises from infection within the invaginated canal, rather than the main canal. If the invagination can be accessed and managed using standard endodontic protocols—cleaning, shaping, disinfection, and obturation—while preserving the main pulp tissue, periradicular healing may be achieved without the need for full root canal treatment.
Nallapati (2004) described a surgical approach involving retrograde obturation at the point where the invagination communicates with the periodontal ligament, along with partial resection of the invagination to improve access. However, in the present case, conservative orthograde treatment of the invagination alone was sufficient, and pulp vitality was preserved throughout follow-up.
Instrumentation and irrigation of the invagination present unique risks, particularly in immature teeth with an open apex and absent buccal cortical plate. The risk of sodium hypochlorite extrusion is significant under these conditions.
Therefore, CBCT should be used preoperatively to evaluate for possible fenestrations. Additionally, precautions such as side-vented irrigation needles, reduced irrigation pressure, and/or the use of negative-pressure systems are strongly recommended (Behrents et al., 2012; Souza et al., 2021).
Obturation also requires careful consideration. While gutta-percha may be suitable in some cases, calcium silicate–based materials are preferred when the apical anatomy is irregular or lacks a natural constriction, as is common in Type IIIB cases. In this report, MTA (Angelus) was selected due to its biocompatibility and sealing properties and was compacted using a NiTi plugger 60/04 (Fanta Dental Materials, Shanghai, China). Radiographs were taken during obturation to ensure proper adaptation and compaction of the material.
Conclusion
Successful management of dens invaginatus requires thorough clinical and radiographic assessment, with CBCT playing a key role in evaluating the anatomy and extent of the invagination. In cases with a positive pulp sensibility response, treatment may be limited to the invagination canal alone, provided proper disinfection and obturation protocols are followed. This conservative approach can promote periapical healing while preserving pulp vitality and maintaining normal tooth function.
Alani A, Bishop K (2008) Dens invaginatus. Part 1: classification, prevalence and aetiology. International Endodontic Journal 41, 23–36.
Atkinson SR (1943) The permanent maxillary lateral incisor. American Journal of Orthodontics and Oral Surgery 29, 685–698.
Behrents KT, Speer ML, Noujeim M (2012) Sodium hypochlorite accident with evaluation by cone beam computed tomography. International Endodontic Journal 45, 492–498.
Bishop K, Alani A (2008) Dens invaginatus. Part 2: clinical and radiographic features and management options. International Endodontic Journal 41, 1137–1154.
Dembinskaite A, Veberiene R, Machiulskiene V (2018) Successful treatment of dens invaginatus type III with infected invagination, vital pulp, and cystic lesion: a case report. Clinical Case Reports 6, 1565–1570.
Hallett GE (1953) The incidence, nature, and clinical significance of palatal invaginations in the maxillary incisor teeth. Proceedings of the Royal Society of Medicine 46, 491–499.
Hamasha AA, Alomari QD (2004) Prevalence of dens invaginatus in Jordanian adults. International Endodontic Journal 37, 307–310.
Kamio N, Gomyo N, Matsushima K (2021) Successful pulp-preserving treatment for peri-invagination periodontitis of double dens invaginatus with Oehlers type IIIA and IIIB: a case report. Journal of Endodontics 47, 1515–1520.
Karaca I, Toller MO (1992) Multiple bilateral dens in dente involving all the premolars: a case report. Australian Dental Journal 37, 449–452.
Kronfeld R (1934) Dens in dente. Journal of Dental Research 14, 49–66.
Nallapati S (2004) Clinical management of a maxillary lateral incisor with vital pulp and type III dens invaginatus: a case report. Journal of Endodontics 30, 726–731.
Oehlers FA (1957) Dens invaginatus (dilated composite odontome). I. Variations of the invagination process and associated anterior crown forms. Oral Surgery, Oral Medicine and Oral Pathology 10, 1204–1218.
Patel S (2010) The use of cone beam computed tomography in the conservative management of dens invaginatus: a case report. International Endodontic Journal 43, 707–713.
Rushton MA (1958) Invaginated teeth (dens in dente): contents of the invagination. Oral Surgery, Oral Medicine and Oral Pathology 11, 1378–1387.
Sarnat BG, Schour I (1941) Enamel hypoplasia (chronologic enamel aplasia) in relation to systemic disease: a chronologic, morphologic and etiologic classification. Journal of the American Dental Association 29, 67–75.
Schwartz SA, Schindler WG (1996) Management of a maxillary canine with dens invaginatus and a vital pulp. Journal of Endodontics 22, 493–496.
Siqueira JF Jr, Rôças IN, Hernández SR, Brisson-Suárez K, Baasch AC, Pérez AR, Alves FRF (2022) Dens invaginatus: clinical implications and antimicrobial endodontic treatment considerations. Journal of Endodontics 48, 161–170.
Souza EM, Campos MG, Rosas Aguilar R (2021) Mapping the periapex anatomical pattern of teeth involved in sodium hypochlorite accidents: a cross-sectional quasi-experimental study. International Endodontic Journal 54, 1212–1220.
Tavano SM, de Souza SM, Bramante CM (1994) Dens invaginatus in first mandibular premolar. Endodontics and Dental Traumatology 10, 27–29.
Zoya A, Ali S, Alam S, Tewari RK, Mishra SK, Kumar A, Mukhtar-Un-Nisar Andrabi S (2015) Double dens invaginatus with multiple canals in a maxillary central incisor: retreatment and management of complications. Journal of Endodontics 41, 1927–1932.