mahgol mehrabani

Regenerative endodontic procedures (REPs) have emerged as a biologically driven approach for managing immature teeth with necrotic pulp and open apices, providing an alternative to traditional apexification techniques. This case report describes the successful treatment of a three-rooted immature mandibular first molar with necrotic pulp and chronic apical periodontitis in a 9-year-old patient using REPs. The treatment followed the guidelines set by the American Association of Endodontists and utilized a two-visit protocol. Concentrated growth factor (CGF) was employed as a biological scaffold in the root canals, while calcium-enriched mixture (CEM) cement was used for the coronal seal. Radiographic evaluations conducted at 6, 12, and 15 months revealed progressive periapical healing, significant root elongation, increased thickness of the root walls, and partial apical closure. Clinically, the patient remained asymptomatic during all follow-ups. This case highlights the potential of CGF and CEM cement-enhanced REPs to promote continued root development and achieve predictable outcomes in immature teeth with necrotic pulps, offering a biologically based alternative to conventional apexification.

This study aimed to compare the effects of requirement-based and test-based formative assessment methods on pre-clinical endodontic competence and performance of dental students.

This interventional field study was conducted on dental students of Shahid Beheshti Dental School in the first and second semesters of 2021 academic year (third-year students), taking practical basic endodontics 1. After receiving theoretical instructions and practical demonstrations, the students in both groups were asked to perform root canal therapy for extracted maxillary anterior and mandibular/maxillary canine teeth as part of their requirement. Their errors were assessed and recorded by two calibratedinstructors. Next, group 1 students performed root canal therapy for mandibular incisors and premolars as their requirement and returned the treated teeth on a specific date every 3 weeks. Group 2 students did not have a specific requirement and only participated in an examination which included endodontic treatment of the same group of teeth treated by group 1 students at the same designated dates. The treated teeth were assessed by instructors for errors. A final examination was held at the end of the semester for both groups. The two groups were compared by independent t-test, ANCOVA, Pearson Chi-square, and Mann-Whitney tests (alpha=0.05).

No significant difference was found between the two groups in access cavity preparation, root canal instrumentation, or obturation (P>0.05).

Requirement-based and test-based formative assessment methods had similar effects on pre-clinical endodontic competence and performance of dental students

 During root canal preparation, dentinal chips, irrigants, and pulp remnants are extruded into the pre-radicular space. This phenomenon may lead to post-endodontic flare-ups. Furthermore, different preparation systems may be associated with varying amounts of apically extruded debris. This study aimed to compare the amount of debris extrusion using two endodontic preparation systems: ProTaper Universal and SafeSiders.

 In this in vitro study, 30 single-rooted human mandibular premolars with fully developed apices and curvatures of 0-10 degrees were randomly assigned to two groups (N=15). The root canals were prepared with the ProTaper Universal and the SafeSiders system according to the manufacturer’s instructions. Extruded debris was collected into pre-weighed tubes by washing the apical foramen area with 1cc of distilled water. After incubating tubes for ten days to evaporate the remaining irrigants, the amount of apically extruded debris was calculated by subtracting each tube's initial and final weight. Data were analyzed by Student t-test at P<0.05.

 The mean values for the amount of apically extruded debris using ProTaper Universal and SafeSiders system were 0.0018±0.0004 g and 0.0023±0.0006 g, respectively. The two groups had a statistically significant difference regarding the amount of the apically extruded debris. The SafeSiders system caused significantly more debris extrusion than the ProTaper Universal system (p<0.01).

 Both the ProTaper Universal rotary system and the SafeSiders reciprocating system caused apical debris extrusion; However, ProTaper Universal was associated with less debris extrusion.

In this case report, the regeneration method was used to treat the previously treated first molar, which presented with symptoms of pain during chewing and secondary acute apical periodontitis.Due to the importance of preserving the patient's permanent teeth in order to maintain optimal space and function, the regeneration treatment was performed in two visits and according to the American Association of Endodontists (AAE) guidelines. The continuation of tooth root development, healing of periapical radiolucency and positive response to sensibility test (cold test) were observed during follow-up radiographs at intervals of 6 months, 1 year & 2 year.

This study aimed to compare the incidence of dentinal crack formation by instrumentation with ProTaper Universal system (rotary, multi-file system), SafeSider (reciprocation movement, multi-file system) and Neolix (rotary, single-file system).
Methods and Materials: In this in vitro study, 60 freshly extracted mandibular first molars were randomly divided into three experimental groups (n=15) and a control group containing unprepared teeth (n=15). Instrumentation in different groups was accomplished using either ProTaper, Neolix or SafeSider systems up to 25/0.08. The teeth were then sectioned at 3, 6 and 9 mm from the apex, and observed under a stereomicroscope for presence of dentinal cracks. Data were analyzed with Chi square test, Fisher’s exact test and Bonferroni correction.
Micro cracks were seen in all experimental groups (13.3% in ProTaper, 26.7% in SafeSider and 40% in Neolix). There was a significant difference between Neolix and the control groups in microcrack formation (P=0.042). Micro cracks mainly occurred in the coronal section (9 mm). No microcrack occurred in the control group.
Neolix rotary single-file system caused more dentinal cracks compared to the unprepared roots. All the instrumentation systems increased the number of micro cracks compared to unprepared teeth.