Time-Dependent Morphological Changes in Traumatic Immature Teeth With Necrotic Pulps Following Regenerative Endodontic Treatment: A Retrospective Study.

BACKGROUND/AIM: Regenerative endodontic treatment is a promising approach for healing periapical lesions and continuous root maturation. Although previous studies have reported its outcomes, the dynamics of morphological changes over time remain unclear. Therefore, this study aimed to evaluate changes in the periapical status and root dimensions over a 60-month follow-up period. MATERIALS AND METHODS: The follow-up duration, periapical status changes, calcific barrier formation, degree of apical closure and radiographic root area changes were compared with those of the last follow-up in this retrospective study. Radiographic root area changes were calculated as the difference between the total root and total canal areas. RESULTS: Fifty-eight patients (81 teeth) underwent regenerative endodontic treatment during the study period, of whom 32 patients (36 teeth, 62%) were included. The survival and success rates of the treated teeth were 100% and 94.4%, respectively. All teeth developed a calcific bridge in the cervical third of the root canal, indicating the presence of vital tissue. Apical narrowing (partial or total) was observed in 75% of the cases. The root maturation stage affected the percentage increase in the radiographic root area. Teeth in Cvek stages II-III showed a higher radiographic root area increase than more mature teeth. All tooth radiographic root areas increased significantly in the initial 20 months of the treatment and moderately thereafter. CONCLUSIONS: Regenerative endodontic treatment is a safe approach for traumatised immature teeth. The presence of a radiographic calcified bridge may be an early indication of treatment success. The main complete tooth morphological changes occur after approximately 20 months posttreatment. These findings may help clinicians better understand the time-dependent changes in the root morphology after treatment, improve the follow-up schedule and predict the progress of healing during follow-up visits.

Effect of sodium hypochlorite on dentin microhardness.

This study was designed to evaluate the effect on root dentin microhardness of 2.5% and 6% sodium hypochlorite solutions for various irrigation periods. Forty-two bovine roots were divided into seven groups. The control group was irrigated with saline. The experimental samples were continuously irrigated with 2.5% or 6% NaOCl for 5, 10, or 20 min. Microhardness was measured at depths of 500 mum, 1000 mum, and 1500 mum from the lumen. A decrease in microhardness was found at 500 mum between the control and samples irrigated with 6% NaOCl and 2.5% NaOCl (p = 0.352, p = 0.084 respectively) at all irrigation periods. There also was a significant difference in groups irrigated for 10 or 20 min (p = 0.001, p < 0.001 respectively). At all distances, the decrease in microhardness was more marked after irrigation with 6% NaOCl than 2.5% NaOCl.