Wadim Leontiev

This in-vitro study aimed to evaluate the temperature development on root surfaces of mature single rooted teeth during guided endodontics preparations performed in a continuous and intermittent mode, and during conventional post preparation. Sixty extracted human teeth were divided into three groups and cut horizontally at the level of the cementoenamel junction. In 40 specimens, mechanical preparation was performed with a defined continuous maximum force of 10N in a universal testing machine: 20 were prepared using a guided endodontics bur (Group CGE) and 20 using a post-preparation bur (Group CPP). The remaining 20 specimens were prepared at low force using the guided endodontics bur in intermittent steps of 2-3mm with intermediate irrigation (Group IGE) until the defined depth of 7mm was reached. Temperature change on the root surface was recorded using two temperature probes attached to the buccal and proximal root surface. For all three groups, preparations were performed in a water bath at 37°C to simulate oral conditions. A significant higher temperature change was observed in group CGE, especially on the proximal surface (mean 42.5°C; 95% CI 39.1 - 46.0), compared to group CPP proximal (mean 37.7°C; 95% CI 37.5 - 37.9; p < 0.05). Temperature change in group IGE proximal (mean 38.5°C; 95% CI 37.8 - 39.1) was similar to group CPP. When performing static guided endodontics, intermittent preparation including irrigation avoids harming temperature changes on the root surface and leads to a heat development similar to conventional post preparation.

Objectives: This study compared conventional access cavity preparation (CONV) and real-time guided endodontics (RTGE) in teeth with pulp canal calcification (PCC) regarding the rate of detected root canals, substance loss and procedural time. Materials and methods: A total of 72 extracted, sound human teeth (48 incisors, 24 canines) with PCC were matched in pairs, divided into two groups of 36 teeth each. An endodontic specialist performed CONV, while a general dentist not specialized in endodontics utilized RTGE on six models each, under simulated clinical conditions. The operators recorded the time to access the calcified root canals. Pre- and postoperative cone-beam computed tomography (CBCT) scans were obtained to measure substance loss. Statistical significance was tested by examining the overlap of 95% confidence intervals (CIs) and Fisher’s exact test. Results: RTGE had a marginally higher success rate (34/36) in detecting root canals compared to CONV (32/36) (p =.67). While RTGE resulted in less substance loss (CI: 9–14.3 mm³ vs. 15–24.2 mm³), it required more procedural time than CONV (CI: 11.6–17.8 min vs. 1.4–2.5 min). Conclusions: Both CONV by a specialist and RTGE by a general dentist achieved a high detection rate of root canals, with RTGE resulting in superior tooth substance preservation but at the expense of longer operation times. Clinical relevance: RTGE can be considered as an alternative technique for non-specialists when treating teeth with PCC, emphasizing procedural safety and effective canal detection.

Objective: This study aimed to evaluate the effectiveness of a 3D printed training kit for the preparation of endodontic access cavities in calcified teeth.Methods: The root canal system of a micro-CT scanned premolar was digitally processed to create an endodontic training kit containing 10 teeth with ten different progressive degrees of pulp canal calcification. A tooth variant with a medium calcification degree (5/10) was printed in three copies using opaque resin. Additionally, a set of 10 transparent training teeth with red-colored pulp was produced using PolyJet 3D printing technology, which was used to train the access cavity preparation in a controlled manner due to the transparency of the teeth. Undergraduate students (n=27) and dentists (n=10) each prepared a total of 13 (one pre-training, two post-training) access cavities. Substance loss was quantified by CBCT, and user satisfaction was evaluated by questionnaire. Paired t-tests were used to compare the means for substance loss and procedure time for pre- and post-training conditions. Unpaired t-tests were used to compare differences between students and dentists. The level of significance was set at α=0.05.Results: Mean substance loss before and after training decreased for both students (71.4 versus 54.68 mm3; p=0.069) and dentists (67.3 versus 51.1 mm3; p=0.633), but the difference was not statistically significant. The average preparation time decreased with training for students (420 versus 275 seconds; p=0.100) and dentists (336 versus 158 seconds; p=0.054), but not significantly. Root perforation rates also decreased (students: 6/27 versus 4/27; dentists: 1/10 versus 0/10). Participants rated the training model as very realistic and useful, despite the difference in material texture.Conclusion: The proposed 3D printed training kit appears to be a suitable tool for undergraduate dental students, which could expand their opportunities to practice the preparation of endodontic access cavities in calcified teeth. (EEJ-2024-06-091)

Die Kalzifikation von Wurzelkanälen erschwert die Präparation einer adäquaten Zugangskavität im Rahmen der Wurzelkanalbehandlung. Neben dem dentalen Trauma, insbesondere der Dislokationsverletzung, führen auch andere, nicht traumatische Stimuli zur Kalzifikation des Wurzelkanalsystems. Bei der konventionellen Trepanation können je nach Ausprägung der Kalzifikation Komplikationen den Erfolg der Wurzelkanalbehandlung mindern und damit den Zahnerhalt gefährden. Mittels dreidimensionaler Bildgebung und der Möglichkeit, die Zugangskavität präoperativ digital zu planen und anschließend mit einer Bohrschablone auf die klinische Situation zu übertragen, können auch in Fällen mit ausgeprägter Kalzifikation endodontische Zugangskavitäten bis in den apikalen Bereich präzise und minimalinvasiv präpariert werden. Article published online: 14 May 2024 © 2024. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Objectives: To compare the efficacy of fiber post removal using conventional (CONV) versus guided endodontics (GE) in terms of dentin loss, residual resin material, procedural errors, and working time in vitro. Material and methods: Ninety human central incisors were root-filled and scanned by micro-computed tomography (CT), then restored with fiber posts and composite. Twenty-four sets of teeth with up to four human maxillary central incisors were fabricated and divided into three groups: conventional post removal by a general dentist (CG) or endodontology specialist (CS) and guided endodontics (GE) by a general dentist, yielding 30 teeth per operator and group. After treatment, the prepared access cavities were volumetrically assessed by micro-CT. Statistical significance was evaluated by one-way analysis of variance followed by post hoc comparisons with Tukey's HSD test and Pearson's chi-squared test for independence. Results: Both CONV and GE resulted in dentin loss and residual resin material. CS resulted in more dentin loss and less residual resin material than CG and GE (p < .05). All groups had some deviations from the original root canal but no perforations. The shortest working time was observed in the GE group. Conclusions: Compared to the conventional freehand technique, GE resulted in significantly less radicular dentin loss, a few deviations but no perforations. Clinical relevance: Guided endodontics can improve the speed and safety of fiber post removal without root perforation.

Background: To compare the outcomes of conventional access cavity preparation (CONV) versus guided endodontics (GE) for access cavity preparation in anterior teeth with pulp canal calcification (PCC) regarding root canal detection, substance loss, procedural time, and need for additional radiographs. Methods: Extracted, sound human teeth with PCC (n = 108) were matched in pairs, divided into two groups and used to produce 18 models. An independent endodontist and a general dentist performed access cavity preparation under simulated clinical conditions on nine models each (54 teeth). The endodontist used the conventional technique and the general dentist GE. Time needed to access the root canals and the number of additional radiographs were recorded. Pre- and postoperative cone-beam computed tomography scans were obtained to measure substance loss. Statistical significance was tested by examining the overlap of 95% confidence intervals (CIs) between the groups. Results: All root canals were successfully accessed by both methods. There were no significant differences in substance loss (CI: CONV 15.9–29.6 mm³ vs. GE 17.6-27.5mm³) or procedural time (CI: CONV 163.3-248.5 s vs. GE 231.9-326.8 s). However, 31 additional radiographs were required for GE compared to none for CONV. Conclusions: For access cavity preparation in teeth with PCC, both CONV by a specialist and GE by a general dentist produce good results in terms of substance loss and time requirements.

The purpose of this ex vivo study was to determine the accuracy of template-based guided endodontics for access cavity preparation and root canal detection in posterior teeth. First, three maxillary and four mandibular models were constructed using 67 premolars and molars, with a total number of 135 main root canals. Cone beam computed tomography (CBCT) and three-dimensional 3D surface scans of each model were performed and matched in order to plan access cavity preparation and design templates virtually. Template-guided access cavity preparation was then performed for each tooth, followed by postoperative CBCT scanning. Deviations between planned and prepared access cavities were measured after superimposition of the pre- and postoperative CBCT scans, and they were analyzed using descriptive and multivariate statistics. All root canals (135/135) were detected utilizing guided endodontics. The mean angle deviation was 1.4 degrees, and the mean deviations at the tip and base of the bur were 0.24–0.31 mm and 0.26–0.29 mm, respectively. This study demonstrated that guided endodontics is an accurate and predictable method for endodontic access cavity preparation in posterior teeth.

Distinguishing composite remnants from tooth structure after trauma splint removal can be challenging. This study aimed to compare the Fluorescence-aided Identification Technique (FIT) with conventional light illumination (CONV) in terms of accuracy and time required for the detection of composite remnants after trauma splint removal. Ten bovine tooth models containing anterior teeth from 12 to 22 with composite remnants after trauma splint removal were used. These models were examined by 10 students and 10 general dentists. Each examiner assessed the 10 models using CONV or FIT three times with an interval of 2 weeks each using a prototype fluorescence-inducing headlamp with a spectral bandwidth of (405 ± 7) nm for FIT and a dental unit lamp for CONV. The examiners charted the location of identified composite remnants, and the procedure time needed for each method was recorded. Statistical analysis was performed with R 3.2.2 software with a significance level of α = 5%. FIT was more accurate and less time-consuming than CONV (p < 0.001). There were no significant differences between dentists and students concerning accuracy (CONV: p = 0.26; FIT: p = 0.73). Students performed FIT significantly faster than the dentists (p < 0.001). FIT is a quick and reliable method of identifying composite remnants after trauma splint removal.