Exploring age and gender variations in root canal morphology of maxillary premolars in Saudi sub population: a cross-sectional CBCT study.

BACKGROUND: In complex teeth like maxillary premolars, endodontic treatment success depends on a complete comprehension of root canal anatomy. The research on mandibular premolars' root canal anatomy has been extensive and well-documented in existing literature. However, there appears to be a notable gap in available data concerning the root canal anatomy of maxillary premolars. This study aimed to explore the root canal morphology of maxillary premolars using cone-beam computed tomography (CBCT) imaging, considering age and gender variations. METHODS: From 500 patient CBCT scans, 787 maxillary premolar teeth were evaluated. The sample was divided by gender and age (10-20, 21-30, 31-40, 41-50, 51-60, and 61 years and older). Ahmed et al. classification system was used to record root canal morphology. RESULTS: The most frequent classifications for right maxillary 1st premolars were 2MPM1 B1 L1 (39.03%) and 1MPM1 (2.81%), while the most frequent classifications for right maxillary 2nd premolars were 2MPM1 B1 L1 (39.08%) and 1MPM1 (17.85%). Most of the premolars typically had two roots (left maxillary first premolars: 81.5%, left maxillary second premolars: 82.7%, right maxillary first premolars: 74.4%, right maxillary second premolars: 75.7%). Left and right maxillary 1st premolars for classes 1MPM1 and 1MPM1-2-1 showed significant gender differences. For classifications 1MPM1 and 1MPM1-2-1, age-related changes were seen in the left and right maxillary first premolars. CONCLUSION: This study provides novel insights into the root canal anatomy of maxillary premolars within the Saudi population, addressing a notable gap in the literature specific to this demographic. Through CBCT imaging and analysis of large sample sizes, the complex and diverse nature of root canal morphology in these teeth among Saudi individuals is elucidated. The findings underscore the importance of CBCT imaging in precise treatment planning and decision-making tailored to the Saudi population. Consideration of age and gender-related variations further enhances understanding and aids in personalized endodontic interventions within this demographic.

Morphology and classification of the second mesiobuccal canal in maxillary first molars: a cone-beam computed tomography analysis in a Chinese population.

BACKGROUND: Understanding the tooth anatomy is crucial for ensuring effective endodontic treatment. This study investigated the root canal morphology of the second mesiobuccal (MB2) canal in maxillary first molars (MFMs) in a Chinese population using cone-beam computed tomography (CBCT). METHODS: This study evaluated 486 MFMs with MB2 canals from 285 participants undergoing CBCT examination and determined the Vertucci's classification and position of the MB2 canal orifice. The prevalence of the MB2 canal was correlated with the sex, age, and tooth side. The correlations between the prevalence of the MB2 canal and sex and tooth side were assessed using the Fisher's exact test. The chi-square test was used for evaluating the correlation between the prevalence of the MB2 canal and age. RESULTS: The number of type II, III, IV, V, VI, VII, and other root canals in the MFMs was 30.9%, 0.6%, 65.0%, 1.2%, 1.2%, 0.4%, and 0.6%, respectively. Among the 201 cases with bilateral inclusion, 87.6% showed consistent canal configuration. Results of the first clear apparent position (FCAP) of the MB2 canals showed that 434, 44, and 3 teeth had FCAP at the upper, middle, and bottom one-third of the root, respectively. The FCAPs of the MB2 canal in the MFMs with types II, IV, and VI, as well as types III and V canals showed significant differences (p<0.05). The horizontal distance between the MB1 and MB2 canal orifices in the type II canals of MFMs was significantly lesser than those in the type IV canals of MFMs (p < 0.01). The longitudinal distance between the pulp chamber floor plane and MB2 canal orifice significantly correlated with age (p < 0.05). CONCLUSIONS: The morphology of the mesiobuccal root canal in the MFMs is complex. Complete understanding of the anatomical morphology of the root canal combined with the CBCT and dental operating microscope is necessary for the accurate detection of the MB2 canal and consequently improved success rate of root canal treatment. Our study findings can help endodontists improve endodontic treatment outcomes.

A systematic review and meta-analysis of the prevalence and global distribution of middle mesial canals in mandibular molars identified by CBCT.

OBJECTIVES: This systematic review and meta-analysis aimed to evaluate the prevalence of middle mesial canal (MMC) in permanent mandibular molars of different populations and regions based on cone-beam computed tomography (CBCT) studies. MATERIALS AND METHODS: PubMed, Scopus, Embase, Web of Science, and Open-Grey were searched up to October 2023 according to specific keywords. A hand search was conducted on the references of the included studies and articles from three peer-reviewed journals in endodontics. The main variable of interest was the prevalence of MMC. Additional data such as the total number of included cases, age and country of the population, CBCT device information, voxel size, and field of view details were also extracted. Extracted data were analyzed qualitatively with the JBI quality assessment checklist and quantitatively with STATA software. RESULTS: Of 32,793 studied teeth, the cumulative prevalence of MMC in both mandibular 1st and 2nd molars was 3.11% (95% CI: 2.00-4.44%). The subgroup analysis reveals a prevalence of 4.15% (95% CI: 2.69-5.89%) for mandibular 1st molars and 1.2% (95% CI: 0.2-2.83%) for mandibular 2nd molars. The highest prevalence of MMC in 1st molar was attributed to South Asia (11.24%) and Africa (6.61%). CONCLUSIONS: The prevalence of MMC varies among regions. Clinicians should be aware of the potential prevalence of MMC, particularly in mandibular first molars, as a missed MMC could result in endodontic failure. CLINICAL RELEVANCE: The presence of MMCs varies in different geographic regions (0% to 29.7%). Clinicians should always look for MMC when doing an endodontic treatment on mandibular molars, as the presence of this canal is not uncommon. We suggest searching for this canal as if searching for the second mesiobuccal canal of maxillary 1st molars.

Evaluation of various obturation techniques with bioceramic sealers in 3D-printed C-shaped canals.

This in vitro study compared various obturation techniques with bioceramic sealers for filling C-shaped 3D-printed replicas. A mandibular molar with a C-shaped root canal with a C1 configuration was obtained. After instrumenting with M3 Pro Gold files (United Dental, Shanghai, China) up to size #30/0.04, a CBCT scan of the tooth was taken. Sixty 3D-printed replicas of the tooth were created. The samples were obturated with EndoSeal TCS sealer (E. TCS; Maruchi, Wonju, Korea) or EndoSeal MTA (E. MTA; Maruchi, Wonju, Korea) (n = 30). The samples in each group were obturated with the following techniques (n = 10): (1) single-cone technique (SC), (2) SC with ultrasonic activation (UA), and (3) cold hydraulic compaction (CHC). Following incubation, the replicas' apical, middle, and coronal thirds were inspected under a digital microscope, and the proportion of filling material and void were calculated. Also, the obturation time and sealer extrusion were recorded. Data were analyzed using ANOVA, LSD post-hoc, and the chi-square tests (α = 0.05). The results indicated that in the apical third, E. TCS-SC, E. TCS-UA, and E. MTA-UA had the lowest void percentage among groups (p < 0.05). In the middle thirds, samples obturated with E. TCS-UA showed a significantly lower void percentage among all groups (p < 0.05). However, in the coronal third, E. TCS-CHC showed the least void percentage (p < 0.05), followed by E. TCS-UA and E. MTA-CHC. The E. TCS-SC and E. TCS-UA were the least time-consuming methods (p < 0.05). Sealer extrusion significantly differed among the groups, with E. MTA-UA and E. TCS-UA showing higher incidence (p = 0.019). It was concluded that E. TCS-UA was the most convenient obturation technique. However, care must be taken when obturating the canals with high flow and ultrasonic activation near the vital anatomical landmarks.

Efficacy of electronic apex locators in comparison with intraoral radiographs in working length determination- a systematic review and meta-analysis.

BACKGROUND: Successful endodontic treatment needs accurate determination of working length (WL). Electronic apex locators (EALs) were presented as an alternative to radiographic methods; and since then, they have evolved and gained popularity in the determination of WL. However, there is insufficient evidence on the post-operative pain, adequacy, and accuracy of EALs in determining WL. OBJECTIVE: The systematic review and meta-analysis aims to gather evidence regarding the effectiveness of EALs for WL determination when compared to different imaging techniques along with postoperative pain associated with WL determination, the number of radiographs taken during the procedure, the time taken, and the adverse effects. METHODS: For the review, clinical studies with cross-over and parallel-arm randomized controlled trials (RCTs) were searched in seven electronic databases, followed by cross-referencing of the selected studies and related research synthesis. Risk of bias (RoB) assessment was carried out with Cochrane's RoB tool and a random-effects model was used. The meta-analysis was performed with the RevMan software 5.4.1. RESULTS: Eleven eligible RCTs were incorporated into the review and eight RCTs into the meta-analysis, of which five had high RoB and the remaining six had unclear RoB. Following meta-analysis, no significant difference in postoperative pain was found among the EAL and radiograph groups (SMD 0.00, CI .29 to .28, 354 participants; P value = 0.98). Radiograph group showed better WL accuracy (SMD 0.55, CI .11 to .99, 254 participants; P value = 0.02), while the EAL group had 10% better WL adequacy (RR 1.10, CI 1.03-1.18, 573 participants; P value = 0.006). CONCLUSION: We found very low-certainty evidence to support the efficacy of different types of EAL compared to radiography for the outcomes tested. We were unable to reach any conclusions about the superiority of any type of EAL. Well-planned RCTs need to be conducted by standardizing the outcomes and outcome measurement methods.

Volumetric Analysis of Hand and Rotary Instrumentation, Root Canal Filling Techniques, and Obturation Materials in Primary Teeth Using Spiral CT.

AIM AND BACKGROUND: To compare the root canal volume in primary teeth using hand and rotary instruments and to evaluate root canal filling techniques and flow of root canal obturation materials in the postinstrumented root canal volume using spiral computed tomography (SCT). MATERIALS AND METHODS: Freshly extracted 16 primary molars were randomly divided into two groups and subjected to SCT analysis before and after instrumentation. For the manual technique (group I) with eight teeth were prepared using K files, and rotary (group II) eight teeth preparation was performed with ProTaper files. The filled volume in each canal was measured using SCT, and the percentage of obturated volume was calculated. The data were statistically analyzed using the Mann-Whitney U test. RESULTS: There was a statistically significant difference in both groups' volume of root canals enlarged. Even though both K files and the ProTaper system brought about enlarged canals after instrumentation, there was a statistically significant increase in volume after using K files in two canals. In three canals, there was a statistically significant increase in volume after using ProTaper. Irrespective of the obturation technique and materials used, there is no statistically significant difference in the volume after obturation. CONCLUSION: From the results of this study, the ProTaper file system shows suitable volumetric enlargement up to an optimum level, which is needed in primary root canal walls, and is better in canal shaping, as evidenced by good postobturation volume. CLINICAL SIGNIFICANCE: The traditional method of cleaning and shaping the root canals in permanent teeth using manual stainless-steel files can lead to undesirable curvatures in root canal morphology, making correctly filling the root canals difficult. It is also time-consuming and sometimes leads to iatrogenic errors. Rotary nickel-titanium (Ni-Ti) instrumentation techniques have been developed to overcome these problems. How to cite this article: Yadav DBUC, Varma RB, Kumar JS, et al. Volumetric Analysis of Hand and Rotary Instrumentation, Root Canal Filling Techniques, and Obturation Materials in Primary Teeth Using Spiral CT. J Contemp Dent Pract 2024;25(3):250-259.

Micro-computed tomographic evaluation on the quality of single-cone obturation using a modified passive-deflation sealer injection needle: an in vitro study.

OBJECTIVES: This study aimed to design a modified passive-deflation sealer injection needle and investigate its ability to improve obturation quality of single-cone technique through assessing the distribution of voids in root canals using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Forty-eight mandibular incisors were divided into eight groups (n = 6), according to the taper of root canal preparation (0.06 or 0.04), the needle used for sealer injection (modified or commercial iRoot SP injection needle), and the obturation method (iRoot SP sealer-only or single-cone obturation). After obturation, each specimen was scanned by micro-CT. The volumetric percentage and distribution of all voids were first analyzed and compared among groups, then the open and closed voids were separately analyzed and compared among single-cone obturation groups. RESULTS: Compared to commercial needle groups, modified needle groups showed much less voids, especially in the apical root canal part (P < 0.05). Besides, the modified needle groups produced much less open voids than commercial needle groups despite the root canal taper (P < 0.05). CONCLUSIONS: The modified passive deflation sealer injection needle could effectively improve the quality of single-cone obturation through reducing intra-canal voids, especially open voids throughout the root canal, thus might possibly be developed as an effective intra-canal sealer delivering instrument.

Microcomputed tomography analysis of curved root canal preparation when coronal flaring and glide path files used with heat-treated nickel titanium rotary files.

The objective was to evaluate the effect of glide path and coronal flaring on the dentin volume removal and percentage of touched walls in curved canals using two heat-treated rotary files. The mesiobuccal canal of forty-eight, randomly selected, extracted mandibular molars was divided into two groups of 24 each, according to the type of instrument used (RACE EVO and EdgeSequel rotary files). Each group was further divided into three subgroups; Group (A): Control using one file shaped to 04/30, Group (B) with a glide path (EdgeGlidePath (EGP)), and Group (C): with a glide path and coronal flaring (EGP and EdgeTaper Platinum (ETP) SX file respectively). The root canals were then instrumented using the assigned instruments. The assessment was carried out using micro-CT. The comparison of the mean values of the tested groups about dentin volume removal and percentage of untouched walls did not reach statistical significance (p<0.05). Glide path and coronal flaring had an insignificant effect on the dentin volume removal and percentage of untouched walls in curved canals.

Diagnostic value of cone beam computed tomography for root canal morphology assessment - a micro-CT based comparison.

OBJECTIVES: The aim of this study was to assess cone beam computed tomography (CBCT) as a root canal anatomy diagnostic tool by comparison with micro-CT gold-standard. MATERIALS AND METHODS: 216 two-rooted mandibular molars were first scanned in a CBCT device (200 µm voxel size) and posteriorly in a micro-CT scanner (19.61 µm). The volumes were sequentially screened to classify main root canal anatomy according to Vertucci classification, and for the presence of lateral canals and apical deltas, in both mesial and distal roots. RESULTS: Both methods revealed a higher prevalence of Vertucci Type II and IV in the mesial root, and Vertucci Type I in the distal root. The percentage of agreement for main root canal anatomy classification between CBCT and micro-CT scores was high (85.2%). CONCLUSION: Sensibility to detect both lateral canals and apical deltas with CBCT was low. These results attest to the fact that minor anatomical changes might be difficult to identify with CBCT imaging, hampering its diagnostic value.

Influence of Different Glide Path Techniques on Microcrack Formation after Two Different Root Canal Preparation Treatments: Micro Computed Tomography Analysis.

OBJECTIVE: This study aimed to evaluate the effect of WaveOne Glider (WOGG) with Waveone Gold (WOG) primary reciprocation systems on root dentine microcrack formation and to know the effect of TruNatomy Glider (TRNG) with TruNatomy (TRN) prime rotary systems on root dentine microcrack formation. METHODS: In this study, 40 extracted mandibular first molar roots were selected and divided randomly into four groups (n=10). Group MWOG: a manual glide path was performed + WOG primary. Group MTRN: manual glide path performed+TRN prime. Additionally, group WOGG: glide path preparation with WOGG+WOG primary. Finally, for group TRNG, the glide path preparation was performed with TRNG+TRN prime. Micro-CT was used for pre and post-instrumentation image analysis. Statistical analysis was performed using the Kruskal- Wallis test (p<0.05) with Two-way ANOVA. RESULTS: The Kruskal-Wallis test showed no significant differences among all groups in all thirds for pre and post-instrumentation regarding the crack formation. The Two-way ANOVA showed no significant difference or interaction between the ways of glide path preparation, whether manual or reciprocal WOGG, or between the rotary TRNG and the motion used in root canal preparation (rotary TRN or reciprocal WOG) regarding the crack formation and propagation. CONCLUSION: Microcrack formation and propagation occurred independently of using different glide path techniques (manual, rotary, or reciprocal).

Natural canal deviation and dentin thickness of mesial root canals of mandibular first molars assessed by microcomputed tomography.

The aim of this study was to assess the centralization and dentin thickness of mesial root canals of the first mandibular molars by microcomputed tomography (micro-CT). Material and methods: Ninety-nine mandibular molars of Vertucci's type IV canals were scanned by micro-CT. The mesiodistal deviation and centroid were assessed, in both mesiobuccal (MB) and mesiolingual (ML) canals, for the apical 4mm and the full canal length. Results: The dentin thickness was similar for both MB and ML canals. The narrowest thickness was in the distal wall of an MB canal (0.07mm), while the widest was found in the mesial wall of an MB canal (2.46mm). In centroid analysis, both the MB and ML canals exhibited deviations when compared to the root centroid, along the full canal length and the apical 4mm. For the MB canal, the mean deviation was 0.83mm (0.02 mm-2.30 mm) for the full canal and 0.18mm (0.01 mm-1.01 mm) for apical 4mm. Similarly, for the ML canal, the mean deviation measured 0.83 mm (0.05mm-3.99mm) for the full canal and 0.21 mm (0.01mm-1.01mm) for the apical 4 mm. Overall, deviations were observed towards the mesial of the roots, with 69% for MB and 57% for ML canals for the full canal, and 51% for MB canals within the 4 mm. The exception was the ML canal, which exhibited a higher deviation towards distal in the apical 4mm, accounting for 52% of cases. The dentin thickness was consistent between the mesial canals of mandibular molars. However, there is no centrality of mesial canals in their roots, with frequent deviation to mesial.

Comparative evaluation of volumetric changes between two pediatric rotary files (Kedo-S plus, Kedo-SG blue) and manual files (hand K-files) during canal preparation of primary mandibular molars: an in-vitro nano-CT analysis.

Pediatric endodontics has become popular due to advancements in cleaning, shaping and irrigation systems, resulting in faster and effective removal of infected pulp, saving time, and creating a pathogen-free environment. The patented rotary file system, Kedo-S, designed for primary teeth, introduced a single file generation for efficient pulp therapy. However, there are currently no studies assessing canal preparation in primary mandibular molars using nano-CT (computed Tomography). To evaluate the volumetric changes of two recently introduced pediatric rotary file systems in comparison with conventional hand file systems in primary mandibular molar using an ultra-high resolution nano-CT. This in-vitro study was performed in extracted primary mandibular molar based on certain inclusion and exclusion criteria. Samples were prepared and working length was determined before the pre-operative scan using a high resolution nano-CT device (SkyScan 2214, Bruker, Kontich, Belgium). A single well-experienced pediatric dentist prepared the canals using three file systems: Kedo-S plus, Kedo-SG blue and Hand K-files. A post-operative scan was performed similar to pre-operative scan. Image reconstruction was performed with NRecon software for 3D volumetric visualization and analysis of the root canals. Kedo-SG blue file systems had the highest mean difference in the canal volume (8.85%). Hand K-files had the least difference at (1.24%) of canal volume. Kedo-S plus file system had a mean canal volume difference (6.14%) which is closer to hand K-files. Rotary file systems resulted in a significant enlargement of canals compared to hand files.

Evaluating the Internal Anatomy of Maxillary Premolars in an Adult Saudi Subpopulation Using 2 Classifications: A CBCT-Based Retrospective Study.

BACKGROUND Understanding the root canal morphology is important for successful endodontic treatment. This retrospective cone-beam computed tomography (CBCT) study aimed to compare the adult maxillary premolars (MP), root, and canal morphology among a Saudi Arabian subpopulation based on Vertucci and Ahmed classifications. MATERIAL AND METHODS Scans of 1336 MP - 656 first premolars (MFP) and 680 second premolars (MSP) - were analyzed for the number of roots, morphology of the canals, and symmetry among them. The data were grouped based on the traditional preestablished Vertucci system and newer instantaneous code-based Ahmed classification. Comparative analysis was done using the chi-square test. RESULTS Two roots were common in MFP with 84.4% of the population, followed by those with 1 root and those with 3 roots. In MSP, single roots were more common. The results were non-significant with P values of 0.859 and 0.471, respectively. Most of these MFP had Type IV Vertucci configuration/²TNB¹P¹ Ahmed et al code (TN-tooth number, B-buccal canal, P-palatal canal). In MSP, Type I Vertucci/¹TN¹ Ahmed et al code was most common. However, the results were not statistically significant for the PM with P values of 0.997 and 0.732, respectively. Sex-based difference among them for the roots and root canals was also non-significant. Symmetry among PM in opposite quadrants was 87.1% in MFP and 90% in MSP. CONCLUSIONS Two roots with Type IV (²TNB¹P¹) and 1 root with Type I (¹TN¹) were most common in MFP and MSP, respectively. Symmetry among opposing PM was high.

Comparative evaluation of volumetric changes following rotary and hand files' canal preparation of primary maxillary canine: an in vitro nano-CT analysis.

PURPOSE: To evaluate the volumetric changes of two recently introduced paediatric rotary file systems in comparison with conventional hand file systems in primary maxillary canines using an ultra-high-resolution nano-computed tomography. METHODS: This in vitro study was performed in extracted primary maxillary canines based on certain inclusion and exclusion criteria. Samples were prepared, and working length was determined after the pre-operative scan using a high-resolution nano-CT device (SkyScan 2214, Bruker, Kontich, Belgium). A single well-experienced paediatric dentist prepared the canals using three file systems: Kedo-S plus, Kedo-SG blue and hand K-files. All samples were subjected to post-operative scans performed similar to pre-operative scans. Image reconstruction was performed with NRecon software for 3D volumetric visualisation and analysis of the root canals. RESULTS: Kedo-SG blue file systems had the highest mean difference in the canal volume (4.05%). Hand K-files had the least difference at (3.71%) of canal volume. Kedo-S plus file system had a moderate mean canal volume difference (3.82%) which is closer to hand K-files. Intergroup comparison between the three groups showed that the mean difference in canal volume was statistically significant between all three file systems (p = 0.000). CONCLUSION: Within the limitations of the current study, rotary file systems produced a significant enlargement of canals as compared to hand files. Kedo-SG blue created a uniform preparation of the canal cervico-apically. Kedo-S plus files were prepared more coronally with minimal preparation apically as close to the preparation of hand files. TRIAL REGISTRATION: Trial registration number: IHEC/SDC/PEDO-2103/22/651, Date of registration: 2022.

Assessment of the root and canal morphology in the permanent dentition of Saudi Arabian population using cone beam computed and micro-computed tomography - a systematic review.

INTRODUCTION: Root canal treatment procedures require a thorough understanding of root and canal anatomy. The purpose of this systematic review was to examine the morphological differences of teeth root and their canals assessed using cone-beam computed and micro-computed tomography in Saudi Arabian population. METHODOLOGY: An electronic search was conducted in PubMed / Medline, Scopus, Google Scholar, and Web of Science databases until January 2023 to retrieve related studies. "Root canal morphology," "Saudi Arabia," "Micro-CT," and "cone-beam computed tomography" were used as keywords. A modified version of previously published risk of bias assessment tool was used to determine the quality assessment of included studies. RESULTS: The literature search revealed 47 studies that matched the criteria for inclusion, out of which 44 studies used cone beam computed tomography (CBCT) and three were micro-computed tomography (micro-CT) studies. According to the modified version of risk of bias assessment tool, the studies were categorized as low, moderate, and high risk of bias. A total of 47,612 samples were included which comprised of either maxillary teeth (5,412), or mandibular teeth (20,572), and mixed teeth (21,327). 265 samples were used in micro-CT studies while 47,347 teeth samples were used in CBCT studies. Among the CBCT studies, except for three, all the studies were retrospective studies. Frequently used imaging machine and software were 3D Accuitomo 170 and Morita's i-Dixel 3D imaging software respectively. Minimum and maximum voxel sizes were 75 and 300 µm, Vertucci's classification was mostly used to classify the root canal morphology of the teeth. The included micro-CT studies were in-vitro studies where SkyScan 1172 X-ray scanner was the imaging machine with pixel size ranging between 13.4 and 27.4 µm. Vertucci, Ahmed et al. and Pomeranz et al. classifications were applied to classify the root canal morphology. CONCLUSION: This systematic review revealed wide variations in root and canal morphology of Saudi population using high resolution imaging techniques. Clinicians should be aware of the common and unusual root and canal anatomy before commencing root canal treatment. Future micro-CT studies are needed to provide additional qualitative and quantitative data presentations.

Micro-computed tomographic evaluation of the shaping ability of three nickel-titanium rotary systems in the middle mesial canal of mandibular first molars: an ex vivo study based on 3D printed tooth replicas.

BACKGROUND: The preparation of the middle mesial (MM) canal of mandibular molars represents a challenge because it is often curved, narrow, and close to the root concave. The purpose of this study was to evaluate the ex vivo shaping ability of 3 nickel-titanium (NiTi) rotary systems in the MM canal using 3D printed resin tooth replicas. METHODS: A permanent mandibular first molar with a MM canal was acquired from a pool of extracted teeth and reproduced by a 3D printer. The resin tooth replicas (n = 18) were equally assigned to 3 groups for the evaluation of the shaping abilities of 3 NiTi rotary systems (OneShape [OS], Twisted Files [TF], and ProTaper Gold [PTG]) according to the manufacturer's recommendations. The tooth replicas were scanned by micro-computed tomography (micro-CT) twice before and after instrumentation of the mesiobuccal (MB), mesiolingual (ML), and MM root canals. After 3D reconstruction, the canal straightening, change of root canal volume and surface area, the mesial and distal canal wall thickness and canal transportation at the levels of 1, 2, and 3 mm below furcation were assessed. One-way variance analysis and Turkey's post hoc test were used for comparisons of the means among different groups, and paired-t test was used to compare the mesial and distal sides of the mesial roots. RESULTS: As compared with OS and TF, the use of PTG in preparation of MM canals resulted in significantly more straightening of canal curvature (p < 0.05), greater post-instrumentation canal volume and surface area, and thinner mesial and distal remaining canal wall thickness at 1, 2 and 3 mm below furcation (all p < 0.05). Regarding the root canal transportation in the mesiodistal direction, there was no significant difference among the 3 instruments (all p > 0.05) after the preparation of the MB and ML canals. However, in the MM canal, more pronounced transportation was detected in the PTG group at 2 mm below furcation, and in the TF group at 3 mm below furcation as compared with the other 2 systems (both p < 0.05). CONCLUSIONS: 3D printed tooth replicas have the advantages of consistency and can be an ideal model to evaluate the shaping ability of different instruments in the MM canal. OS and TF files performed similarly and both are appropriate for shaping the MM canal, while PTG may cause excessive and uneven resin removal, especially near the furcation, and may lead to root fragility and procedural errors.

Age estimation by pulp canal/root ratio in Yorkshire terrier dogs.

Background: The study of the morphological parameters of teeth on dental radiographic images, especially evaluation of the pulp canal/root ratio (PCRR), has been presented as a reliable method to estimate age both in humans and animals. Evaluating PCRR involves a simple, nondestructive procedure that can be used both in living individuals and in cadavers. There is a scarcity of studies assessing the relationship between PCRR and age in dogs (Canis lupus familiaris). Objective: The aim of this study was to evaluate the relationship between PCRR and age in Yorkshire terrier dogs. Animals and procedures: Dental radiographs of 53 Yorkshire terrier dogs from the database of the Odontovet Veterinary Dentistry Center (Brazil) were analyzed. Using ImageJ software, 3 consecutive measurements of the widths of 2 roots (mesial and distal) and their respective pulp canals were taken at both mandibular molar teeth (left, 309 and right, 409). The PCRR was then calculated using width means. Results: The PCRR decreased with increasing age in both mesial (0.21 ± 0.09 in animals aged < 24 mo, 0.12 ± 0.04 in animals aged between 25 and 96 mo, and 0.09 ± 0.03 in dogs aged > 96 mo) and distal (0.24 ± 0.11, 1.01 ± 0.03, and 0.09 ± 0.03, by the same order) roots. A statistically significant, moderate negative correlation was demonstrated between age and PCRR of the mesial [rs (97) = -0.545; P < 0.001] and distal [rs (98) = -0.578; P < 0.001] roots. Conclusion and clinical relevance: This work contributes to the knowledge of PCRR in dogs and its relationship with age, paving the way for further studies using larger samples in different canine breeds.

Estimation de l'âge par le rapport canal pulpaire/racine chez des chiens de race Yorkshire. Contexte: L'examen des paramètres morphologiques des dents sur des radiographies dentaires, particulièrement l'évaluation du rapport canal pulpaire/racine (PCRR), a été présenté comme une méthode fiable d'estimer l'âge chez les humains et les animaux. L'évaluation du PCRR est faite au moyen d'une procédure simple et non-destructive qui peut être utilisée autant chez les individus vivants que sur des cadavres. Il y a peu d'études évaluant la relation entre le PCRR et l'âge chez les chiens (Canis lupus familiaris). Objectif: L'objectif de la présente étude était d'évaluer la relation entre le PCRR et l'âge chez des chiens de race Yorkshire. Animaux et procédures: Les radiographies dentaires de 53 chiens de race Yorkshire provenant de la base de données du Centre de dentisterie vétérinaire Odontovet (Brésil) ont été analysées. À l'aide du logiciel ImageJ, 3 mesures consécutives de la largeur de 2 racines (mésiale et distale) et de leur canal pulpaire respectif ont été prises au niveau des dents molaires mandibulaires (gauche, 309 et droite, 409). Le PCRR a par la suite été calculé utilisant les moyennes des largeurs. Résultats: Le PCRR diminuait avec une augmentation de l'âge autant pour la racine mésiale (0,21 ± 0,09 chez les animaux âgés de < 24 mo, 0,12 ± 0,04 chez les animaux âgés entre 25 et 96 mo, et 0,09 ± 0,03 chez les chiens de > 96 mo) que pour la racine distale (0,24 ± 0,11, 1,01 ± 0,03, 0,09 ± 0,03, dans le même ordre d'âge). Une différence statistiquement significative, corrélation modérément négative a été mise en évidence entre l'âge et le PCRR pour la racine mésiale [rs (97) = −0,545; P < 0,001] et la racine distale [rs (98) = −0,578; P < 0,001]. Conclusion et pertinence clinique: Cette étude contribue à la connaissance du PCRR chez les chiens et sa relation avec l'âge, ouvrant la voie à des études ultérieures avec un échantillonnage plus grand et différentes races de chien.(Traduit par Dr Serge Messier).

Cone-beam Computed Tomography Analysis of the Root Canal Morphology of Mandibular Incisors Using Two Classification Systems in a Spanish Subpopulation: A Cross-Sectional Study.

OBJECTIVE: This study evaluated the root and canal morphology in permanent mandibular incisors teeth using cone-beam computer tomography imaging in a Spanish subpopulation, and compared these findings with ipsilateral (similarity) and contralateral (symmetry) incisors. In addition, the position of canal splitting was measured. METHODS: A total of 229 datasets comprising four mandibular teeth each (n=916 incisors) were analysed using Vertucci and Ahmed et al. classifications, and, the similarity and symmetry were calculated. The distance from the cemento-enamel junction (CEJ), and the most coronal canal divergence was measured (if present). The role of sex was also assessed. The Cochran Q Test, LOGIS PROC in SUDAAN, Chi-square, and Kappa were used for the different comparisons. A p-value of less than 0.05 was considered significant. RESULTS: All incisors were single-rooted and no significant differences regarding root canal morphology were found according to the sex of the subjects included in the database. The most common morphology was Vertucci type I/Ahmed et al. 1MI1(65.3% for central and 66.8% for lateral incisors respectively), followed by type III/1MI1-2-1 (31% for central and 30.6% for lateral incisors). 1.8% of the samples were considered as non-classifiable with Vertucci but were classified with codes using the Ahmed et al. system. Similarity values were 74.7% for the left side, and 74.2% for the right side, whereas symmetry values were 90% for central and 84.3% for lateral incisors. In the presence of divergences, the main (SD) distances from the CEJ were for type II/1MI1-2-1 3.8+-0.8 (centrals) 4.0+-0.7 mm (laterals); for type V/1MI1-2 this value ranged between 6.0+-1.8 and 5.5+-1.5 mm, whereas values for 1MI1-2-3-2-1 were 1.8 and 2.1 mm. No significant differences were found when the position of the most coronal divergence was compared between lateral and central incisors for the different morphologies. CONCLUSION: A high prevalence of Vertucci I/Ahmed et al. 1MI1 configuration was present in mandibular incisors from Spanish individuals. Similarity and symmetry were common, particularly for central incisors. The position of the coronal splitting of the canals varied according to the root canal morphology.

Microcomputed tomographic evaluation of 6 NiTi files on the pericervical dentin and the smallest dentin thickness zones in mesial root canals of mandibular molars: an in vitro study.

OBJECTIVE: The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars. MATERIALS AND METHODS: Sixty mandibular molars with two mesial canals and Vertucci configuration were aleatory allocated in 6 experimental groups of 10 molars and 20 root canals. Specimens were scanned before instrumentation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WaveOne Gold (WG), group 2 with Reciproc Blue (RB), group 3 with TRUShape (TS), group 4 with XP-endo Shaper (XP), group 5 with iRace (IR), and group 6 with TruNatomy (TN). After instrumentation, the molars were scanned again and the images recorded were reconstructed with the NRecon v.1.7 (Bruker micro-CT) and analyzed with CTAn v.1.20.8 software (Bruker micro-CT) quantifying the changes produced in the surface, volume, structure thickness, SMI, and centroids at the Pericervical Dentin area of the root canals (PCD) located from the root canal orifices at the floor of the pulp chamber to 4 mm in the apical direction, and the changes in the Smallest Dentin Thickness Zones (SDTZ) located (from the furcation to 4 mm and 7 mm in the apical direction. The data obtained were compared using Wilcoxon and ANOVA with a 5% significance level. RESULTS: XP and TN were similar in all the parameters (P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR (P <.05), while XP showed significant differences from WG (P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN (P>.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal (P <.05). CONCLUSIONS: XP and TN rotatory files with small taper and volume maintained better with minor changes at the PCD and SDTZ, while WG reciprocation file produced the largest change. All the files were maintained centered at the PCD, and their performances were safe with a minimal thickness higher 0.5 mm at the SDTZ, and without risk of perforation. TRIAL REGISTRATION: No clinical trials were indicated in this study. CLINICAL RELEVANCE: The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments.

Retrospective study of the morphology of third maxillary molars among the population of Lower Silesia based on analysis of cone beam computed tomography.

INTRODUCTION: Understanding the anatomy of root canal systems and being aware of their variations is crucial for successful endodontic treatment. Specifically, the intricate and diverse nature of the root anatomy in maxillary third molars poses a significant challenge for dental clinicians. The study analyzed the morphology of the root canal system in maxillary third molars among residents of the Lower Silesia region in Poland using cone beam computed tomography (CBCT). MATERIAL AND METHODS: This retrospective cross-sectional imaging study was conducted at the X-Ray Diagnostics Laboratory of the Academic Dental Polyclinic of Wroclaw Medical University, Poland. The study evaluated 316 CBCT scans and included 196 maxillary third molars. They were obtained from 118 females and 78 males over the age of 18, in the period from January to April 2022 (three consecutive months). The number of roots, root canals, and root canal configurations according to Vertucci's classification were analyzed. RESULTS: Three-rooted maxillary molars were found most often (64.29%), followed by single-rooted (24.49%), two-rooted (7.65%), and four-rooted (3.57%) teeth. Among all the roots examined, Vertucci Type I root canals were the most prevalent. Our research found that single-rooted forms (40 teeth, 33.89% vs. 8 teeth, 10.26%, p = 0.0013) of maxillary third molars were significantly more common in females than in males. However, three-rooted forms (62 teeth, 79.49% vs. 64 teeth, 54.24%, p = 0.0013) of maxillary third molars were significantly more common in males than in females. DISCUSSION: In the Lower Silesia region, the typical maxillary third molar in the Polish population has a three-rooted structure with Vertucci Type I root canal configuration. We noted a sex-dependent correlation in maxillary third molar morphology, with single-rooted forms more prevalent in women and three-rooted forms in men.