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Context: Root perforation increases the fracture risk, and bioceramic materials can be used for repair. Evaluating the fracture resistance (FR) of these cements in teeth with simulated perforations is crucial for assessing their effectiveness. Aim: The aim of the study was to evaluate the effect of Biodentine (Septodont, France) and Mineral Trioxide Aggregate High Plasticity (MTA Repair HP, Angelus, Brazil), on the FR of teeth with simulated root perforations. Design and Settings: An in vitro experimental design was conducted to compare and determine the most reliable repair and obturating material for root perforation. Materials and Methods: Fifty extracted mandibular premolars were randomly assigned to one control group (n = 10) and four test groups (n = 10) based on the repair and backfilling materials used: Biodentine + gutta percha (GP) (Dentsply Maillefer, Germany) and AH Plus sealer (Dentsply, Germany), Biodentine + Biodentine, MTA HP + GP and sealer, and MTA HP + MTA HP. FR was assessed using a universal testing machine. Statistical Analysis: The variance among the five groups was tested using Analysis of Variance and pairwise post hoc Tukey's test for intergroup comparisons. The level of statistical significance was set at P < 0.05. Results: The highest mean FR value was observed in the MTA HP + MTA HP group. ANOVA test revealed statistically significant differences between the groups (P < 0.05). Conclusion: Bioceramic cements with a MOE similar to dentin enhance FR by forming a monoblock for uniform stress distribution. Perforation repair and backfilling with these cement reinforce the tooth. [ABSTRACT FROM AUTHOR]

Background: Chelating agents used to remove the inorganic part of the smear layer from prepared canals can alter dentin mineral composition, potentially affecting the adhesion of resin-based root canal cement and sealers. Aim: This study aimed to compare the decalcifying effects of 17% ethylenediaminetetraacetic acid (EDTA), 20% N-acetyl cysteine (NAC), and deionized water (control) on root canal dentin using energy-dispersive X-ray spectroscopy (EDXS). Materials and Methods: Sixty-nine extracted human mandibular premolars were randomly divided into three groups, yielding 138 root halves treated with either 17% EDTA, 20% NAC, or a control solution (n = 46). The mineral content was assessed using EDXS, and statistical analysis was conducted with the Kruskal–Wallis test, using an alpha level of 5%. Results: Twenty percent NAC and control groups retained more calcium, magnesium, and phosphorus than 17% EDTA, suggesting better mineral preservation, while 17% EDTA resulted in the lowest mineral content across all elements analyzed. Conclusion: Twenty percent NAC exhibited milder decalcifying effects compared to EDTA while preserving mineral content. Twenty percent NAC could be a biocompatible alternative to EDTA for smear layer removal in endodontic treatments. [ABSTRACT FROM AUTHOR]

The influence of the ferrule thickness and post materials on the fracture resistance of endodontically treated teeth remains unclear. The purpose of this laboratory study was to evaluate the influence of post material and ferrule thickness on the fracture resistance of endodontically treated mandibular premolars. Sixty-four extracted and endodontically treated mandibular first premolars were used and divided into 4 test groups (n=16) depending on the ferrule thickness: F-0: without a ferrule, F-0.5: with a 0.5-mm ferrule thickness, F-1: with a 1-mm ferrule thickness, and F-1.5: with a 1.5-mm ferrule thickness. In groups with ferrules, the height ranged from 2 mm buccally/lingually to 1 mm proximally. Teeth in subgroups (n=8) were restored with either prefabricated glass fiber (FF) or titanium posts (FT) (ISO size 70 and length of 7.5 mm) and then adhesively restored with composite resin foundation materials. After foundation procedures, each specimen was restored with a cobalt chromium crown which was cemented with glass ionomer cement. All specimens were subjected to dynamic loading in a masticatory simulator for 1 200 000 loading cycles with a nominal load of 5 Kg at 1.2 Hz and simultaneous thermocycling (5 to 55 °C). Specimens were then quasistatically loaded at 30 degrees in a universal testing machine until fracture. Fracture loads were analyzed by using 2-way ANOVA followed by the Tukey honestly significant difference test (α=.05). Fracture loads ranged from 610 ±45 N (no ferrule – glass fiber post) to 1216 ±169 N (1.5 mm ferrule thickness – glass fiber post). A statistically significant increase in fracture resistance was observed with increasing ferrule thickness (P <.001). However, post materials did not show a statistically significant influence (P =.977). Under the conditions of this laboratory study, increasing the ferrule thickness had a significant effect on the fracture resistance of endodontically treated teeth after thermomechanical fatigue, irrespective of post materials. [ABSTRACT FROM AUTHOR]

The traditional endodontic cavity (TEC) facilitates canal preparation, but may increase susceptibility to root fracture; conservative endodontic cavities (CEC) aim to preserve tooth structure to maintain the structural integrity of root-filled teeth. The objective of this study was to evaluate the effect of access cavity design and the degree of pulp chamber root removal on the microstrain distribution patterns under different levels of functional loading using digital moiré interferometry. Twelve extracted human teeth (n = 12) were included, comprising of mandibular premolars (n = 6) and mandibular first molars (n = 6). Specimens were subjected to physiologic levels of compressive loading ranging from 10 to 50 N for each group. Digital moiré interferometry fringe patterns were acquired three times for each pecimen: prior to endodontic cavity preparation (control group (CG)), after conservative endodontic cavity preparation (CEC), and following traditional endodontic cavity preparation (TEC). The acquired fringe patterns were used to determine the microstrain distribution at the coronal and cervical dentin. The data were analyzed qualitatively and quantitatively using one-way ANOVA and T-tests (P <.05). The intact crowns of CG teeth showed significantly less microstrain, when compared to CEC and TEC with a distinct shift in coronal microstrain in both CEC and TEC groups. There were significant differences between both the coronal and cervical microstrain in the CG, CEC, and TEC groups. The roof of the pulp chamber contributes to a distinct biomechanical response in posterior teeth. The microstrain at the coronal and cervical level increased significantly following de-roofing of the pulp chamber in both CEC and TEC groups, with the TEC resulting in higher coronal microstrain compared to CEC group. [ABSTRACT FROM AUTHOR]

Introduction: Eradication of residual biofilm from root canal dentine is critical for the success of regenerative endodontic procedures (REPs). The aim of the study: To evaluate the influence of ultrasonically activated irrigants in concentrations used for REPs for removal of dual-species biofilm from three-dimensionally printed tooth models with attached dentine samples. Methodology: Seventy-two three-dimensionally printed teeth models were fabricated with a standardized slot in the apical third of the root to ensure a precise fit with a human root dentine specimen. Dual-species biofilms (comprising Enterococcus faecalis and Streptococcus mutans) were cultivated in the root canal for a period of three weeks. Models with dentine specimens were randomly assigned into 5 groups according to the irrigation protocol; G1(dis H2O): infected root canals irrigated with distilled water to serve as controls; G2(1.5% NaOCl): 1.5% NaOCl for five minutes; G3(1.5% NaOCl + PUI): 1.5% NaOCl + passive ultrasonic irrigation (PUI) for 30 s; G4(3% NaOCl): 3% NaOCl for five minutes; G5(3% NaOCl + PUI): 3% NaOCl + PUI for 30 s. Bacterial reduction was determined by colony-forming unit (CFU) counting (n = 12/G), whilst biofilms were analyzed using field emission scanning electron microscopy in additional samples. Results: The four experimental groups showed a significant reduction in CFU counts compared to the control group (p < 0.05). When compared with (dis H2O), the highest reduction in bacterial count was obtained in G5 (3% NaOCl + PUI) followed by G4 (3% NaOCl), then G3 (1.5% NaOCl + PUI), and finally G2 (1.5% NaOCl). Conclusion: Results of the current study propose that a 3D-printed mature tooth model can be effectively used to analyze the antimicrobial effects of different irrigation protocols on dual-species biofilm. The use of NaOCl in concentrations used for regenerative endodontics can effectively remove bacterial biofilms. Furthermore, the use of PUI did not significantly enhance antibacterial effects of NaOCl. [ABSTRACT FROM AUTHOR]

Background: In dentistry, local anesthetic is frequently used to manage pain throughout several phases of dental treatments, including tooth extraction. The study aimed to compare the effectiveness of two techniques for controlling pain during mandibular exodontia (tooth extraction), specifically focusing on the pain experienced during injection and extraction of mandibular anterior and premolars teeth. The two techniques being compared are the intraligamentary injection technique (ILI) and the incisive nerve block technique (INB). Materials and methods: In this study, 100 mandibular anterior and premolars and teeth that were indicated for extraction were included. The effectiveness of the two local anaesthesia techniques, intraligamentary injection technique (ILI) and incisive nerve block (INB), were compared using Modified Dental Anxiety Scale for Dental Extraction Procedure (MDAS-DEP) and visual analogue scale (VAS) during the injection and extraction stages of the procedure. Results: A total of 100 participants (42 females, 58 males) with a mean age of 50.97 ± 11.59 years took part in the study. The mean VAS score in the INB group was 6.14 after injection and 3.86 after extraction, while in the ILI group, it was 5.46 and 2.90, respectively. There was a statistically significant difference between the two groups both after injection (p = 0.001) and extraction (p < 0.001), as well as within each group (Control: p < 0.001; Study: p < 0.001). For MDAS-DEP, the INB group had mean scores of 15.86 and 11.26 after injection and extraction, respectively, while the ILI group had scores of 15.68 and 10.94, showing a significant difference within each group after both injection (p < 0.001) and extraction (p = 0.001). However, no significant difference was found when comparing MDAS-DEP scores between the two groups from injection to extraction (p = 0.802). Conclusion: The intraligamentary injection technique (ILI) appears less painful during injection and provides profound pain relief during extraction. The results suggest that ILI can be used as a sole anaesthetic technique during extraction of lower anterior and premolar teeth. Trial registration: This trial was retrospectively registered on 27/01/2023 with the identifier ISRCTN83272316 in Isrctn.com. [ABSTRACT FROM AUTHOR]

Introduction: Managing intraoperative pain while initiating root canal treatment necessitates the use of supplementary injection techniques. Aim: The study sought to assess and compare the anesthetic efficacy of 0.5% bupivacaine and 50 mg/ml tramadol hydrochloride versus 2% lignocaine administered as supplemental intraligamentary injection as an adjuvant to an inferior alveolar nerve block (IANB) for mandibular molars with symptomatic irreversible pulpitis (SIP) and normal apical tissues during access cavity preparation. Materials and Methods: Two hundred and two individuals with mandibular molars diagnosed with SIP with normal apical tissues and exhibiting moderate-to-intense pain were given 2 ml of IANB containing 2% lignocaine and 1:80,000 epinephrine. The Visual Analog Scale (VAS) was used to record intraoperative discomfort. Individuals who scored more than 5 on the VAS were deemed to need further anesthesia. The intraligamentary medication was given to 99 of these patients after they were randomly assigned to 3 groups (2% lignocaine, 0.5% bupivacaine, and 50 mg/ml tramadol). VAS score was again recorded. If the patient reported no pain during the opening of the access, it was deemed a success. The post hoc Tukey's test, paired t -test, and one-way analysis of variance were the statistical methods used to examine the data. Results: Maximum reduction in pain was in bupivacaine followed by lignocaine and tramadol (P < 0.05). Subgroup analysis using post hoc Tukey's honestly significant difference test showed a maximum difference between bupivacaine and tramadol (1.273, P > 0.05) (95% confidence interval [CI]), followed by lignocaine and bupivacaine (−1.182, P < 0.05) (95% CI) and lignocaine and tramadol (0.091, P > 0.05) (95% CI). Conclusion: Bupivacaine was most effective in reduction of intraoperative pain when used as an intraligamentary drug during access cavity preparation followed by lignocaine. Tramadol was the least successful drug for achieving effective pulpal anesthesia. [ABSTRACT FROM AUTHOR]

Background: Molariform second premolar is a rare dental anomaly where the second premolar resembles a molar in size and shape. This condition is often linked to macrodontia, a rare enlargement of teeth that disrupts dental proportions and can manifest in isolated, relative, or generalized forms. Although mandibular second premolars are more prone to morphological variability, the occurrence of bilateral molariform premolars, induced by a unique form of gemination, is exceptionally uncommon and infrequently documented, thus making this case clinically significant. Case presentation: This case report illustrates a rare bilateral presentation of molariform second premolars in the mandibular arch of a young patient. Both premolars displayed exaggerated mesiodistal dimensions, molar-like occlusal morphology with multiple cusps, and disproportionate faciolingual dimensions. Diagnosis was established through detailed clinical examination and radiographic evaluations. The report explores the treatment challenges posed by the enlarged tooth size and abnormal morphology, including their impact on orthodontic alignment and restorative planning. The patient was scheduled for reshaping of the macrodont premolars after finishing orthodontic treatment, which was planned for correction of overjet, overbite, as well the deep curve of spee. Conclusions: Molariform premolars, though uncommon, have a profound impact on dental alignment and treatment outcomes. Their morphological uniqueness might potentially be ignored; therefore, dental professionals should remain vigilant for such anomalies during routine examinations to prevent complications like crowding, malocclusion, and caries. Early diagnosis and strategic intervention are crucial for prevention and interdisciplinary management of unexpected complications during dental procedures. This case emphasizes the importance of routine examination and interdisciplinary collaboration in identifying and treating such anomalies. [ABSTRACT FROM AUTHOR]

Background: To evaluate the prevalence and characteristics of taurodontism in northern China by using cone-beam computed tomography (CBCT) and assisting the treatment. Methods: The study involved CBCT scans of 8112 teeth from 507 participants of northern China, comprising 217 males and 290 females aged 18 to 60. Analysis was conducted using Shifman and Chanannel's criteria to assess the prevalence and attributes of taurodontism, examining differences based on tooth position (maxilla and mandible) as well as gender (P < 0.05). Specific morphology including C-shaped canal was recorded. The curvature of the canals was measured using a modified Schneider method. Moreover, we reported two failure cases with taurodontism referred to a retreatment. Results: Taurodontism was observed in 113 participants, affecting 23.50% of the males and 21.38% of the females in at least one tooth (P > 0.05). The prevalence was significant higher in maxilla (P < 0.05). The highest incidence of taurodontism was detected in premolars, 9.86% in the maxillary first premolars, and in molars, with 3.94% in the maxillary first molars. Regarding canal curvature, a higher incidence of curved canal could be found in maxillary and mandibular molars of taurodontism (47.50-66.67%), alongside an elevated prevalence of C-shaped taurodontism in mandibular second molars (71.43%). After follow-up, the healing response was satisfactory in both cases. Conclusion: The study highlighted a higher incidence of taurodontism in maxilla, indicating a significant association between taurodontism, C-shaped characteristics, and canal curvature. Dentists are advised to carefully consider the presence of special morphologies during taurodontism treatment. [ABSTRACT FROM AUTHOR]

Background: This retrospective study aims to characterise the root canal morphology of maxillary and mandibular second molars using cone-beam computed tomography (CBCT). The number of roots and canal configurations were evaluated using both the Vertucci and Benjamı´n Brisen˜ o Marroquı´n classification systems. Methods: A total of 1084 second molar images (523 maxillary; 266 right and 257 left side and 561 mandibular; 285 right and 276 left side) were evaluated from 320 CBCT scans analyzed for the Turkish subpopulation. CBCT imaging provided superior visualisation of root canal anatomy compared to periapical radiography. The findings revealed diverse root canal configurations, with variations observed even within the same population. Statistical analyses, including the chi-squared test, were used to assess correlations between root number and demographic variables such as age and sex. Results: According to Benjamı´n Brisen˜ o Marroquı´n classification system, the most common configuration for upper right three-rooted teeth mesial root was 3URM2−1 (n:66, 35.7%), for distal root was 3URM1 (n:169, 91.4%), and for palatal root was 3URM1 (n:165, 89.2%). Additionally, the most common configuration for upper left three-rooted teeth mesial root was 3271 (n:50, 28.4%), for distal root was 3ULM1 (n:160, 90.9%), and for palatal root was 3ULM1 (n:158, 89.8%). In lower left molars, the most common configuration in the two-rooted teeth mesial root was 2LLM2 (n:114, 49.4%), and for the distal root was 2LLM1 (n:170, 73.6%). For lower right the most common configuration for two-rooted teeth mesial root was 2LRM2 (n:125, 52.5%), and for distal root was 2LRM1 (n:173, 72.7%)(p < 0.05). Conclusion: The primary outcome was observed that the root canal anatomy of upper and lower second molars may differ in both classifications of Turkish subpopulation. While Vertucci's classification was inadequate in some cases, Briseno-Marroquin classification was able to classify all upper and lower second molars with a single code. This new classification is a more useful system for classifying all second molars. There is a statistically significant difference exists among the new configuration according to the distribution of the teeth analyzed. [ABSTRACT FROM AUTHOR]

Objective: Compare the remineralisation potential of four enamel remineralising agents on artificially demineralized enamel surface using Scanning electron microscopy- Energy dispersive x-ray. Materials and methods: 75 extracted maxillary and mandibular premolars coated with acid-resistant nail varnish, were stored in demineralising solution for 96 h to produce artificial caries lesions. The samples were divided into 5 groups (n = 15), Control (Demineralized- No treatment), Group I samples were treated with casein phosphoprotein-amorphous calcium phosphate (CPP-ACP), Group II with self-assembling peptide (SAP-14), Group III with tri-calcium phosphate (f-TCP) and Group IV with Bioactive glass (BAG), respectively. The pH cycling model was followed for 21 days. The samples were analysed via SEM-EDX (Carl Zeiss, Germany; Model: Merlin Compact) for qualitative assessment and quantitative analysis of calcium and phosphorous. The data were analysed for multiple group comparison using IBM SPSS version 20 with one-way ANOVA followed by a paired t-test. Results: Calcium/Phosphorous ratio of all experimental groups; Group 1(1.92 ± .17), Group 2 (1.98 ± .16), Group 3 (1.81 ± .03), Group 4 (1.75 ± .08) was statistically different (p

Dental age estimation, as an important part of forensic anthropology, has a wide range of applications for its results in legal practice. Given the lowered legal age for criminal responsibility in China and the increasing juvenile delinquency, we establish a morphological database targeting the second (M2) and third molars (M3) of the Southern Chinese population. Full mouth orthopantomography from 1486 individuals aged 8.00 to 24.99 years were collected and categorized into five age groups, comprising four age nodes: 12, 14, 16 and 18 years. The Demirjian method assesses M2 and M3 development, and stepwise regression analysis confirms M2's suitability for age estimation. Advanced ML algorithms, such as Random Forest (RF) and Support Vector Machine, are implemented to fit a classification model, evaluated by accuracy. Ultimately, we constructed age estimation models employing techniques such as Decision Trees, AdaBoost, and Voting methods, and assessed their performance using metrics like the mean absolute error (MAE). Among the age estimation models based on different age groups, the Voting model exhibited the most optimal performance, with an average MAE of 0.7207. The estimation model for the 12-14 age group has the highest accuracy, with an average MAE of 0.5081. The RF model has the highest accuracy in the age estimation model for the 12-14 age group, with an MAE of 0.4248. This study effectively integrates multiple ML algorithms to enhance the precision of dental age estimation using M2 and M3, providing a robust method and predictive scheme for forensic practices in ascertaining the age of criminal responsibility., Competing Interests: Declarations. Ethics Approval: This research study was conducted retrospectively from data obtained for clinical purposes. This study was approved by the Ethics Committee of Nanfang Hospital, Southern Medical University (NFEC-2022-298). The material use was reviewed and approved by the Ethics Committee of Nanfang Hospital, Southern Medical University. Consent to Participate: Informed consent for this study was waived by the Ethics Committee of Nanfang Hospital, Southern Medical University. Consent for Publish: All authors have read and approved the final version of the manuscript. Competing Interests: Authors declare that they have no competing interests., (© 2024. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

Objective: This study compared the fracture load, stress distribution, and survival probability under cyclic loading of extensively restored teeth treated with multisonic irrigation with those treated with conventional instrumentation, with or without a post., Methods: Mesial-occlusal-distal cavities were prepared in 30 human mandibular premolars. The teeth were randomly divided into 3 groups of 10 based on the endodontic and restorative procedures: (1) Root canal treatment (RCT) followed by resin composite restoration (control group), (2) RCT followed by a glass fiber post restoration (conventional group), and (3) minimal instrumentation plus multisonic irrigation followed by resin composite restoration (GW group). All groups were restored with full-coverage crowns. The samples were subjected to step-stress cyclic loading until fracture and then scanned using micro-CT to identify the fracture modes. FEA was conducted to evaluate the failure-causing stresses., Results: The mean fracture loads for the control, conventional, and GW groups were 1700 ± 176 N, 1760 ± 97 N, and 1760 ± 70 N, respectively. The respective numbers of cycles to failure were 39461 ± 6634, 41261 ± 3965, and 40151 ± 3127. There was no significant difference in the fracture load or number of cycles to failure among the groups (p > 0.05). This was supported by the FEA results which showed similar critical stress values in the three groups., Significance: The multisonic irrigation system led to a comparable fracture load and durability in extensively restored premolars as conventional RCT with or without a fiber post., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)