A Novel Diagnostic and Treatment Approach to an Unusual Case of Dens Invaginatus in a Mandibular Lateral Incisor Using CBCT and 3D Printing Technology

BACKGROUND

This case report demonstrates the use of three-dimensional (3D) models produced from a cone beam computed tomographic (CBCT) volume to develop a treatment strategy for a rare type of dens invaginatus (DI) in a mandibular incisor.

METHODS

A patient with DI Type IIIa presented for endodontic treatment. Following CBCT evaluation, the complex morphologic nature of the invagination required additional diagnostic tools for treatment planning. The fabrication of 3D models provided clarity regarding the treatment strategy. Treatment involved intracanal medication with calcium hydroxide Ca(OH)2, nonsurgical root canal therapy (NS-RCT) of the main canal, and endodontic surgery for the DI anomaly using mineral trioxide aggregate (MTA), bone graft, and platelet-rich fibrin (PRF) membrane.

RESULTS

The use of 3D models provided an invaluable guide for proper treatment. Complicating factors were diagnosed and planned for accordingly.

CONCLUSIONS

It is difficult to appreciate the anatomical complexity, the extent, and the nature of the invagination of rare Type III DI morphology. CBCT imaging and 3D models played a critical role in the pre-treatment planning to ensure a predictable outcome. A 3D model is recommended as a diagnostic tool in treating complex cases where the DI morphology is wide, oblique, or the foraminal opening is irregular.

A Potential Intracanal Medicament, 2-Hydroxyisocaproic Acid (HICA): Cytotoxicity, Genotoxicity, and Its Effect on SCAP Differentiation

Intracanal medicaments with maximal antimicrobial efficacy and minimal damage to resident stem cells are essential for successful regenerative endodontic procedures. 2-Hydroxyisocaproic acid (HICA) could have the attributes of a potential intracanal medicament. This study evaluates its cytotoxicity, genotoxicity, and effects on the odontogenic and osteogenic differentiation of the stem cells of the apical papilla (SCAP). Cytotoxicity and cell viability assays were performed on cells treated for 24, 48, and 72 h with varying concentrations of HICA and compared to the standard intracanal medicament, calcium hydroxide. The genotoxicity was assessed via immunofluorescence for two markers of DNA double-strand breaks: phosphorylated γH2AX and 53BP1. The SCAP differentiation was evaluated based on the alkaline phosphatase activity, Alizarin Red staining, and expression of odontogenic and osteogenic genes (DSPP1, BSP1, OCN, RUNX2) in the presence of selected HICA concentrations. HICA was not cytotoxic at concentrations up to 10 mg/mL, regardless of the exposure time, although it was cytostatic at all tested concentrations. HICA was not genotoxic at concentrations below 5 mg/mL. No difference in cytotoxicity or genotoxicity was found between HICA and calcium hydroxide at 1 mg/mL. HICA retained about 70% of the osteogenic differentiation potential at 1 mg/mL. Within the limitations of this in vitro study, we show that HICA at 1 mg/mL could be a potential intracanal medicament for REPs.