This micro-CT study analysed 90 mandibular mesial roots with and without a bifid apex. Number of orifices and main apical foramina, main canal counts at coronal/middle/apical thirds, middle mesial canal (MMC) presence, and MB-ML inter-orifice distance in two-orifice roots were measured. The prevalence of MMCs was significantly higher in bifid roots (35.5%) compared to non-bifid roots (11.4%) (p < 0.05). Bifid roots exhibited a significantly higher mean number of apical foramina (2.24 ± 0.43) than non-bifid roots (1.33 ± 0.52) (p < 0.05). In roots with two orifices, the MB-ML inter-orifice distance was significantly wider in the bifid group (2.57 ± 0.56 mm) compared to the non-bifid group (2.28 ± 0.50 mm) (p < 0.05). Canal configurations also differed significantly; bifid roots were predominantly Vertucci Type V (31.1%) and Type IV (26.7%), while non-bifid roots frequently presented with Type I (33.3%) and Type III (26.7%).

AIM:To produce a glossary of controversial terminology relating to a variety of anatomical features of root canals. MATERIALS AND METHODS:A multi-stage consensus process was designed and applied to generate definitions for controversial terms describing root and canal anatomy. The overall direction of the project was provided by an Executive Group, whereas a separate Task & Finish Group was convened to compile a preliminary list of controversial terms together with proposed definitions. This draft was then circulated to an international panel of 32 experts, who took part in an anonymous, web-based Delphi exercise to give independent feedback. Findings from this Delphi round were subsequently examined and debated during a virtual meeting. RESULTS:Following the Delphi exercise, 14 of the 15 proposed terms achieved the pre-specified consensus threshold, with more than 70% of respondents rating them above 7. Consensus was not initially reached for the remaining term ('furcation accessory canal'); its definition was subsequently amended and put through a further Delphi round, after which agreement was achieved. A follow-up virtual meeting involving 19 experts reviewed the Delphi outcomes and proposed further refinements. In response, the Executive Group and Task & Finish Group prepared the final version of the glossary. CONCLUSION:Through a rigorous, structured process of international expert consensus, a glossary addressing controversial terminology in root and canal anatomy has been established. This resource offers a dependable basis for consistent, standardised terminology going forward, with relevance across clinical practice, teaching and research.

This study aimed to evaluate the effect of different post space drill diameters on remaining dentine thickness in maxillary and mandibular molars using high-resolution micro–computed tomography (micro-CT). Sixty molars (30 maxillary, 30 mandibular) with straight or slightly curved roots were allocated into homogeneous groups using pre-existing micro-CT datasets. Post spaces were prepared in the maxillary palatal and mandibular distal roots using Inod drills of three diameters (1.14, 1.25, and 1.55 mm; n = 10 per group). By superimposing pre- and post-preparation scans, the remaining dentine thickness was measured at 1-mm intervals apically from the furcal level (FL) in multiple directions. Data were analysed using ANOVA and post-hoc tests (α = 0.05). Maxillary molars generally retained ≥ 1 mm of dentine thickness across most surfaces and drill sizes, with buccal walls remaining consistently thicker than palatal ones. Only a single perforation occurred (buccal aspect, 1.55 mm group). Conversely, mandibular molars exhibited significantly thinner mesial walls compared to distal walls (p < .05), frequently resulting in postoperative thicknesses of ≤ 1 mm on the mesial surfaces. Furthermore, three perforations occurred on the mesial aspect with the 1.55 mm drill, whereas the distal walls generally maintained ≥ 1 mm thickness without perforations. Drill diameter significantly influences remaining dentine thickness in molar roots. The anatomical dimensions of palatal roots in maxillary molars permit post space preparation with a low risk of perforation, even with larger drills. However, highly conservative preparation or evidence-based post-free alternatives, such as endocrowns, are strongly recommended for mandibular molars.

This study aimed to compare the shaping ability of ProTaper Ultimate, ProTaper Gold, and Reciproc Blue in the mesiobuccal canals of maxillary first molars using micro-computed tomography. Thirty extracted maxillary first molars with Vertucci Type IV configuration and curvatures between 10° and 20° were allocated into three groups (n = 10): ProTaper Ultimate, ProTaper Gold, and Reciproc Blue. All specimens underwent pre- and post-instrumentation micro-computed tomography scanning. Canal transportation, centering ratio, remaining dentin thickness, canal volume, and surface area were evaluated at predefined canal levels. Data were analyzed using one-way analysis of variance (α = 0.05). A significant difference was observed only at the 5 mm level of the MB1 canal, where Reciproc Blue showed a higher centering ratio than ProTaper Gold (p < .05). ProTaper Ultimate resulted in thinner remaining dentin in the furcation region compared with ProTaper Gold (p < .05), although all systems preserved more than 0.3 mm of dentin thickness. MB2 negotiation failures and instrument separation were most frequently observed in the ProTaper Gold group. Although localized differences were observed, all systems preserved canal anatomy with minimal transportation. Reciproc Blue demonstrated superior apical centering, whereas ProTaper Ultimate resulted in slightly thinner dentin in the mesial furcation area. This micro-computed tomography study provides comparative evidence on the shaping behavior of three heat-treated nickel–titanium systems in moderately curved mesiobuccal canals, and the observed differences in centering ability and dentin preservation may assist clinicians in selecting safer instrumentation strategies for complex molar anatomies.

Purpose:This study compared the quality of different filling techniques with two different sizes of isthmuses. Materials and methods:Specimens were produced with a 3D printer (EnvisionTEC Vida, Gladbeck, Germany) and allocated into groups (n=10): Group 1; narrow isthmus with cold lateral compaction (CLC), Group 2; narrow isthmus with warm vertical compaction (WVC), Group 3; wide isthmus with CLC, and Group 4; wide isthmus with WVC. The specimens were sectioned at 4 mm and 8 mm from the apex, and the filling materials and voids in the isthmuses were assessed using ImageJ software (National Institutes of Health, Bethesda, MD, USA). Results:None of the techniques produced void-free fillings. In wide isthmuses, warm vertical compaction (WVC) resulted in significantly greater total void percentages (10.39 ± 8.23%) compared to cold lateral compaction (CLC) (1.30 ± 2.90%) (p = 0.000). In narrow isthmuses, both techniques produced similar void percentages (WVC: 3.33 ± 4.91%, CLC: 1.19 ± 2.67%) (p > 0.05). In the coronal portion of the wide isthmus, the amount of gutta-percha was significantly greater in WVC (p = 0.032), whereas in the apical portion, the sealer percentage was significantly higher in the CLC group. Similarly, in the narrow isthmus groups, the apical sealer percentage was greater in the CLC group (p = 0.000). Conclusion:Both CLC and WVC failed to produce void-free canal fillings in band-shaped isthmuses. WVC showed a higher total void percentage in wide isthmuses, whereas both techniques had similar void percentages in narrow isthmuses.

This study aimed to evaluate the dimensional and sectional compatibility between contemporary nickel–titanium (NiTi) root canal instruments and their corresponding gutta-percha (GP) cones with variable tapers, and to assess their compliance with ISO and ADA standards using micro-computed tomography (Micro-CT). Four NiTi file systems (ProTaper Next X2, HyFlex EDM OneFile, Reciproc Blue R25, and WaveOne Gold Primary) were analyzed. Their compatibility with corresponding GP cones was assessed based on diameter and taper measurements at 1 mm intervals (D1 to D16). Measurements were performed using Micro-CT imaging, and data were analyzed using descriptive statistics, independent t-tests, and one-way ANOVA with Bonferroni post hoc tests (p < 0.05). Compliance with International Organization for Standardization (ISO) and American Dental Association (ADA) standards was also assessed. The findings reveal significant dimensional discrepancies between files and GP cones, with GP cones generally exhibiting larger diameters. Reciprocating systems (WaveOne Gold and Reciproc Blue R25) demonstrated superior compatibility with GP cones compared to rotary systems (ProTaper Next and HyFlex EDM OneFile). GP cones adhered more closely to ISO and ADA standards than files. Significant mismatches were identified between NiTi instruments and their corresponding GP cones. Reciprocating systems showed better dimensional compatibility than rotary systems. These results highlight the need for careful evaluation of material pairing to ensure optimal clinical performance.

PURPOSE:This study aimed to evaluate and compare the marginal and internal fit of permanent crowns fabricated using three different DLP 3D printers and their corresponding permanent resin materials. The fit was quantitatively assessed using micro-computed tomography (micro-CT) and digital 3D analysis. MATERIALS AND METHODS:A premolar tooth was prepared according to conventional ceramic tooth preparation protocols and scanned with an intraoral scanner (TRIOS 5). The resulting standard tessellation language (STL) file was imported into the software for design. A total of 24 crowns were fabricated using three different printer and resin combinations (n = 8): an Asiga printer with Saremco Crowntec permanent resin (Group S), a Denta Fab printer with Power Resin C&B permanent resin (Group C), and a SprintRay printer with Crown permanent resin (Group SP). These crowns were then re-scanned with an intraoral scanner to obtain STL files. Marginal, axial, and occlusal alignment were calculated and compared using 3D analysis software and micro-CT software. As the data were normally distributed, comparisons were made using one-way ANOVA. The significance level was set at p < 0.05. RESULTS:In the marginal area, Group SP demonstrated significantly superior fit compared to Group S (p = 0.002) and Group C (p = 0.0005). No statistically significant difference was observed between Group S and Group C (p = 0.245). The findings obtained from both micro-CT and 3D superimposition analyses were consistent, confirming the reliability and agreement of the two evaluation methods. CONCLUSION:This study demonstrates that crown restorations fabricated using 3D printers exhibit significant variations in fit depending on the type of resin employed. In particular, the resin used in Group SP tended to show improved marginal adaptation compared to Groups S and C, which exhibited comparable results. These findings may offer guidance for clinical decision-making regarding the selection of 3D printing systems and resins for crown fabrication in prosthodontic applications.

BACKGROUND: Endodontic surgery is conducted when previous endodontic treatment has not succeeded, requiring a high level of technical precision. The success of these procedures is crucial for tooth prognosis. Sealing the root end cavity is one of the most important factors for the success of the procedure. The main factors affecting the sealing of the root end cavity are the technique of cavity preparation and the selection of root end filling material. The aim of this study was to compare the gap and void formations of two different MTA-based filling materials during different root end cavity preparation techniques. METHODS: Forty-eight extracted human maxillary incisor teeth were selected. The root canals were prepared with ProTaper Next files to the #X3 file and obturated using single-cone technique. The teeth were randomly divided into two groups (n = 24 each) based on root end cavity preparation techniques (Er: YAG laser and ultrasonic). All root end cavities were prepared to 3 mm depth. Subsequently, they were divided into 2 subgroups (n = 12 each) based on the type of MTA-based root end filling material (MTA Angelus and MTA Flow). The samples were scanned with micro-CT. The volume of filling, total space, void, and gap in root end cavities were calculated. These volumes were saved as percentages. The Mann-Whitney U test was used for comparison. Significance level was taken as p < 0.05. RESULTS: In terms of filling, total space, void, and gap volume percentage, there was no significant difference between the laser and ultrasonic preparation techniques (p > 0.05). MTA Flow demonstrated significantly lower percentages in terms of filling, total space, and void volume than MTA-Angelus (p < 0.05). Root end preparation techniques and root end filling materials did not show a significant difference in terms of gap area percentage (p > 0.05). CONCLUSION: The recently developed MTA Flow with fluid consistency revealed promising and comparable findings with conventional MTA in terms of production of void formation and filling quality in apical surgery.

This study tested the impact of troughing on the detection rates of MB2 canals with and without calcifications. Traditional access cavities were prepared and the detection of MB2 canals was recorded in 200 maxillary molars selected based on micro-CT scans. In specimens, the MB2 orifice was not detected; troughing was performed. The number of negotiated MB2 with and without troughing was compared with micro-CT using McNemar's test. After traditional access cavity preparation without troughing, the operator detected MB2 in 142 specimens (82%). Troughing of the remaining specimens led to the further identification of 16 MB2 canals, increasing detection rate to 91%. Troughing significantly improved the detection rate of non-calcified MB2s (p < 0.05) but did not significantly impact the detection of calcified MB2 canals (p > 0.05). While troughing is highly effective in enhancing MB2 canal detection in non-calcified canals, it may be limited in cases where calcification is present.

This study aimed to investigate the age-related alterations in mesial roots of mandibular first molar in terms of root canal curvature values, dentin thickness, interorifice distance, deviation from apical foramen, and location of apical foramen using a three-dimensional curvature measurement method and micro-computed tomography (micro-CT). Forty-five mesial roots of mandibular first molars from three age groups (Group 1: ≤ 30 years, Group 2: 31–59 years, Group 3: ≥ 60 years) were scanned using micro-CT. The central axis of each mesiobuccal and mesiolingual canal was analyzed using cubic B-spline curves to calculate canal curvature. Dentin thickness, deviation of apical foramen from the anatomical apex, and the location of apical foramen in mesiobuccal and mesiolingual canals were measured and recorded. Statistical analyses, including one-way ANOVA, Mann–Whitney U, Kruskal–Wallis and Pearson’s correlation tests, were performed to assess age-related differences in curvature, interorifice distance, and dentin thickness with a 5

This study aimed to evaluate the influence of root fusion on internal root morphology in maxillary second molars by comparing teeth with fused and independent roots using micro-computed tomography (micro-CT), in terms of inter-orifice distances, lateral and accessory canal distribution, apical anatomy, isthmus prevalence, and type. Three hundred extracted maxillary second molars were classified as having fused or independent roots and scanned using micro-CT. Linear distances between canal orifices, vertical position of MB2, isthmus types, and canal ramifications were analyzed. ROC analysis was performed to determine the diagnostic utility of inter-orifice distances in predicting root fusion. Statistical comparisons between groups were made using independent samples t-tests and Chi-square tests with a significance threshold of 5

Instrument separation during root canal treatment can hinder effective cleaning and shaping, making reliable retrieval techniques essential. Endoscopic visualization might aid in instrument removal procedures offering direct magnification of root canal anatomy. This ex vivo study evaluated the success rate and procedure time of three instrument retrieval techniques - Masserann, microsonic, and loop techniques - under the visualization of dental operation microscope (DOM) assisted by an endoscope. Sixty extracted human mandibular single-rooted teeth with simulated fractures were assigned to the Masserann, microsonic, or ultrasonic with loop techniques (n = 20/group), each performed under endoscopic visualization alongside DOM. The success rate of instrument removal and procedure time were recorded. Complications, such as root perforation, apical extrusion and secondary fracture, were recorded. Statistical analysis was conducted using Pearson χ2 and Kruskal-Wallis tests with 5% significance threshold. Success rates for the microsonic, Masserann, and ultrasonic with loop techniques were 80%, 70%, and 80%, respectively (p > 0.05). The average procedure times were 13.02 min for the microsonic technique, 17.25 min for the Masserann technique, and 17 min for the ultrasonic with loop technique (p > 0.05). The Masserann technique demonstrated a higher complication rate, with two cases each of perforation and apical extrusion, whereas no secondary fractures occurred in any group. Conclusively, the microsonic technique showed the highest success rate with the shortest retrieval time, indicating its efficiency and suitability for instrument removal from root canals, particularly when combined with enhanced visualization through endoscopy.

This study evaluated four file systems (WaveOne Gold, Reciproc Blue, ProTaper Next and TruNatomy) for their shaping efficacy in oval-shaped maxillary premolar root canals using micro-CT. Twenty-four extracted premolars, each with two roots, were randomly divided into four groups (n = 6 teeth/group) and instrumented following manufacturer guidelines. Pre- and post-instrumentation micro-CT scans were performed. Key parameters analysed included unprepared canal surface area (% Un-PrepCA), changes in canal area and volume (ΔCA, ΔCV and their percentages), canal transportation and centring ability. Statistical significance was set at p < 0.05. While no significant differences were found in transportation, centring ability or most 3D parameters (ΔCA, ΔCV and ΔSMI), the TRN group exhibited a significantly higher % Un-PrepCA. Conversely, the WOG group achieved a significantly greater % ΔCA compared to TRN and PTN. All systems performed comparably without procedural errors; TRN resulted in the least canal wall contact, while WOG provided the largest prepared canal area.

This study aimed to evaluate the relationship between two-dimensional orifice shape measurements (major diameter, minor diameter, perimeter, area, roundness, form factor, and aspect ratio) and dentin thickness in the mesial and distal aspects of the distal root canals of mandibular first molars as well as developmental sulcus depth, using micro-CT imaging. A total of 100 distal roots of mandibular first molars showing Vertucci type I configuration was selected and scanned with micro-CT. The 2D micro-CT analysis of area, perimeter, major diameter, minor diameter, roundness, form factor and aspect ratio of the canal orifice was performed. The dentin thickness and developmental sulcus depth were measured in both mesial and distal directions at every mm for 6 mm apical from the furcal level. Whether there was a relationship between the dimensions of the orifice and the difference according to the root level, orifice shape and direction ​​were analyzed with Pearson’s correlation followed by multiple linear regression and Kruskal–Wallis H and Mann–Whitney U analyses in SPSS using 5

This study aimed to compare the effectiveness of manual compaction, indirect ultrasonic activation, and a novel sonic-activated endomotor in reducing voids during MTA placement in perforated internal root resorption cavities (IRR). Thirty standardized 3D-printed resin teeth with simulated perforating IRR cavities (4 mm in diameter, located 4 mm from the apex, with a 2 mm buccal perforation) were fabricated. The samples were randomly divided into 3 groups: Manual compaction: MTA was placed and compacted using hand pluggers. Ultrasonic activation: MTA was placed and indirectly activated with an ultrasonic device at 30

OBJECTIVES:This study aims to investigate whether cumulative dose-dependent isotretinoin (Roaccutane®) could affect orthodontic tooth movement (OTM) and root resorption. MATERIALS AND METHODS:Ninety male Wistar Albino rats were divided into 4 groups. While, the control (SALINE), solvent (SOYBEAN) and orthodontic drug (ISOTM) groups underwent orthodontic force, the non-orthodontic drug group (ISO) did not. The rats were administrated saline, soybean oil (SBO) and isotretinoin diluted in SBO (ISOTM, ISO) for 30 days, respectively. Six rats were euthanized in each orthodontic group. Fifty grams of orthodontic force was applied to the remaining rats' first molars using the incisors as anchorage. Six more rats in each group were euthanized on the 7th, 14th and 21st days of the force application. In the ISO group, six rats were euthanized on the 37th, 44th and 51st days of administration. Six rats that were euthanized for ISOTM on the 30th day were also used for ISO to reduce the number of rats used. Micro-computed tomography (micro-CT) and histological analysis were performed. RESULTS:Independent of orthodontic force, isotretinoin caused root resorption in the apical region. However, there was no statistically significant influence of isotretinoin on OTM and orthodontically induced root resorption (OIRR). CONCLUSIONS:Despite the lack of strong evidence supporting the orthodontically induced resorptive effect of isotretinoin, this study provided findings regarding the resorptive effects of isotretinoin on non-orthodontic root resorption. Therefore, the present results underscore the importance of close monitoring during orthodontic treatment to mitigate potential root resorption in patients who use isotretinoin because of acne complaints.

AIM or PURPOSE The aim of this study was to evaluate the effect of solvent use on dentinal crack formation in during root canal retreatment with micro-CT. MATERIALS and METHOD Root canal treatments were performed on the mesial roots of 20 mandibular molars. The teeth were divided in two groups: Group A: solvent and Group B: Non-solvent. During primary treatment, canal preparation was performed using Revo-S files. The root canals were filled using the lateral compaction technique and AH Plus sealer. During retreatment procedure, Protaper Retreatment Files were used in both groups. Guttasolv was used as solvent during retreatment in group A. Before and after the initial treatment and retreatment, the teeth were imaged using micro-CT. Meanwhile, the remaining root canal filling materials in the teeth were also examined. RESULTS Crack formation was not observed in either group. Residual filling material remained in the root canal after the procedure in both groups and there was no statistical significant difference found in terms of residual matter between the regions according to the results of the measurements made separately in three regions as coronal, middle, and apical regions. CONCLUSION(S) In conclusion, within the limitations of this in vitro study, it could be said that Ni-Ti systems do not cause dentin defects if used with or without a solvent. Even if the retreatment was performed close to ideal, it was determined that residual filling material remained on the canal walls during retreatment.

This study is aimed to evaluate the compatibility of single-cone filling technique in reciprocal and rotationally formed canals in using Micro-CT (Micro-computed tomography). The samples were split into two groups according to the kinematics system used. In both groups, one canal of the shaped roots was filled with the lateral compaction and the other one with a matched single-cone technique with a bioceramic root canal sealer, BioRoot RCS. The percentage of voids in the canal were evaluated by micro-CT radiograph before and after obturation. Regardless of the kinematics used, the single-cone technique left significantly fewer voids than the lateral compaction. In the kinematics comparison, the group shaped with the reciprocal system and filled with the single-cone system had the best results. The reciprocal nickel-titanium (NiTi) system with a matching single-cone gutta percha filling technique was found to be more effective in terms of reducing voids in root canal filling.

Discipline-specific terminology is a central element of the vocabulary used by dentists and scientists in the context of their professional activities and plays a critical role in the understanding of dentistry. A number of controversial terms and non-standardized definitions exist in the field of endodontology. For example, in root and canal anatomy, variations exist in the definitions of root morphology (including apical bifurcation, fusion and dilaceration), pulp chamber anatomy (including the outline of the floor, pulp horns and location of the root canal orifice), apical root canal bifurcations, canal isthmuses, accessory canals and apical foramen. This narrative review provides a critical analysis of a range of controversial terms currently used to describe root and canal anatomy. It also addresses the consequences of using such controversial terms on the accuracy and reliability of research findings and clinical practice.