Second mesiobuccal canal segmentation with YOLOv5 architecture using cone beam computed tomography images.

The objective of this study is to use a deep-learning model based on CNN architecture to detect the second mesiobuccal (MB2) canals, which are seen as a variation in maxillary molars root canals. In the current study, 922 axial sections from 153 patients' cone beam computed tomography (CBCT) images were used. The segmentation method was employed to identify the MB2 canals in maxillary molars that had not previously had endodontic treatment. Labeled images were divided into training (80%), validation (10%) and testing (10%) groups. The artificial intelligence (AI) model was trained using the You Only Look Once v5 (YOLOv5x) architecture with 500 epochs and a learning rate of 0.01. Confusion matrix and receiver-operating characteristic (ROC) analysis were used in the statistical evaluation of the results. The sensitivity of the MB2 canal segmentation model was 0.92, the precision was 0.83, and the F1 score value was 0.87. The area under the curve (AUC) in the ROC graph of the model was 0.84. The mAP value at 0.5 inter-over union (IoU) was found as 0.88. The deep-learning algorithm used showed a high success in the detection of the MB2 canal. The success of the endodontic treatment can be increased and clinicians' time can be preserved using the newly created artificial intelligence-based models to identify variations in root canal anatomy before the treatment.

Amyloid Aggregation of Streptococcus mutans Cnm Influences Its Collagen-Binding Activity.

The cnm gene, coding for the glycosylated collagen- and laminin-binding surface adhesin Cnm, is found in the genomes of approximately 20% of Streptococcus mutans clinical isolates and is associated with systemic infections and increased caries risk. Other surface-associated collagen-binding proteins of S. mutans, such as P1 and WapA, have been demonstrated to form an amyloid quaternary structure with functional implications within biofilms. In silico analysis predicted that the ß-sheet-rich N-terminal collagen-binding domain (CBD) of Cnm has a propensity for amyloid aggregation, whereas the threonine-rich C-terminal domain was predicted to be disorganized. In this study, thioflavin-T fluorescence and electron microscopy were used to show that Cnm forms amyloids in either its native glycosylated or recombinant nonglycosylated form and that the CBD of Cnm is the main amyloidogenic unit of Cnm. We then performed a series of in vitro, ex vivo, and in vivo assays to characterize the amylogenic properties of Cnm. In addition, Congo red birefringence indicated that Cnm is a major amyloidogenic protein of S. mutans biofilms. Competitive binding assays using collagen-coated microtiter plates and dental roots, a substrate rich in collagen, revealed that Cnm monomers inhibit S. mutans binding to collagenous substrates, whereas Cnm amyloid aggregates lose this property. Thus, while Cnm contributes to recognition and initial binding of S. mutans to collagen-rich surfaces, amyloid formation by Cnm might act as a negative regulatory mechanism to modulate collagen-binding activity within S. mutans biofilms and warrants further investigation. IMPORTANCE Streptococcus mutans is a keystone pathogen that promotes caries by acidifying the dental biofilm milieu. The collagen- and laminin-binding glycoprotein Cnm is a virulence factor of S. mutans. Expression of Cnm by S. mutans is hypothesized to contribute to niche expansion, allowing colonization of multiple sites in the body, including collagen-rich surfaces such as dentin and heart valves. Here, we suggest that Cnm function might be modulated by its aggregation status. As a monomer, its primary function is to promote attachment to collagenous substrates via its collagen-binding domain (CBD). However, in later stages of biofilm maturation, the same CBD of Cnm could self-assemble into amyloid fibrils, losing the ability to bind to collagen and likely becoming a component of the biofilm matrix. Our findings shed light on the role of functional amyloids in S. mutans pathobiology and ecology.

A Bioinformatics Systems Biology Analysis of the Current Oral Proteomic Biomarkers and Implications for Diagnosis and Treatment of External Root Resorption.

External root resorption (ERR) is a silent destructive phenomenon detrimental to dental health. ERR may have multiple etiologies such as infection, inflammation, traumatic injuries, pressure, mechanical stimulations, neoplastic conditions, systemic disorders, or idiopathic causes. Often, if undiagnosed and untreated, ERR can lead to the loss of the tooth or multiple teeth. Traditionally, clinicians have relied on radiographs and cone beam computed tomography (CBCT) images for the diagnosis of ERR; however, these techniques are not often precise or definitive and may require exposure of patients to more ionizing radiation than necessary. To overcome these shortcomings, there is an immense need to develop non-invasive approaches such as biomarker screening methods for rapid and precise diagnosis for ERR. In this review, we performed a literature survey for potential salivary or gingival crevicular fluid (GCF) proteomic biomarkers associated with ERR and analyzed the potential pathways leading to ERR. To the best of our knowledge, this is the first proteomics biomarker survey that connects ERR to body biofluids which represents a novel approach to diagnose and even monitor treatment progress for ERR.

Propolis decreases lipopolysaccharide-induced inflammatory mediators in pulp cells and osteoclasts.

BACKGROUND: Intracanal medicaments are used to disinfect the root canal system, reduce interappointment pain and inflammation, and prevent resorption. Bacterial components such as lipopolysaccharide (LPS) are implicated in the development of pulpal and periapical inflammation and inducing osteoclastogenesis. Propolis is a natural, non-toxic substance collected from bee's wax that has been used for many years in folk medicine. Propolis has been demonstrated to have antibacterial and anti-inflammatory properties. Our previous studies have shown that propolis inhibits osteoclast maturation. However, the effect of propolis on the inflammatory response of pulp cells and osteoclasts has not been explored. AIM: The purpose of this study was to evaluate whether propolis alters the inflammatory response of three endodontically relevant cell lines: mouse odontoblast-like cells (MDPC-23), macrophages (RAW264.7), and osteoclasts. MATERIAL AND METHODS: Cells were exposed to 0-20 ug ml(-1) LPS to induce an inflammatory response, in the presence of propolis or vehicle control. Culture supernatants were collected after 6 and 24 h, and expression of multiple soluble mediators was determined using Luminex(®) multiplex technology. RESULTS: Propolis was effective in reducing secretion of the LPS-induced inflammatory cyto/chemokines: IL-1α, IL-6, IL-12(p70), IL-15, G-CSF, TNF-α, MIP-1α, MCP-1, and IP-10. CONCLUSION: Our results demonstrate that propolis suppresses the LPS-induced inflammatory response of key cells within the root canal system.

Anesthesiologist-directed care for elective gastrointestinal endoscopy: results of an Italian multicentric prospective observational study.

BACKGROUND: Sedation, ranging from minimal, moderate and deep sedation to general anesthesia, improves patient comfort and procedure quality in gastrointestinal endoscopy (GIE). There are currently no comprehensive recommendations on sedation practice in diagnostic and therapeutic GIE. We aimed to investigate real-life sedation practice in elective GIE. METHODS: We performed a multicentric observational study across 14 Endoscopy Units in Italy. We recorded consecutive data on all diagnostic procedures performed with Anesthesiologist-directed care (ADC) and all therapeutic procedures performed with ADC or non-Anesthesiologist sedation (NAS) over a three-month period. RESULTS: Dedicated ADC is available five days/week in 28.6% (4/14), four days/week in 21.5% (3/14), three days/week in 35.7% (5/14), two days/week in 7.1% (1/14) and one day/week in 7.1% (1/14) of participating Centers. ADC use for elective diagnostic GIE varied from 18.2% to 75.1% of the total number of procedures performed with ADC among different Centers. ADC use for elective therapeutic GIE varied from 10.8% to 98.9% of the total number of elective therapeutic procedures performed among different Centers. CONCLUSIONS: Our study highlights the lack of standardization and consequent great variability in sedation practice for elective GIE, with ADC being potentially overused for diagnostic procedures and underused for complex therapeutic procedures. A collaborative effort involving Endoscopists, Anesthesiologist and Institutions is needed to optimize sedation practice in GIE.

Quantitative Analysis of Biofilm Removal Following Instrumentation with TRUShape and Vortex Blue File Systems: Microbiological Study.

Mesial roots and isthmuses of mandibular molars are difficult areas to obtain adequate disinfection of root canal walls, and consequently microorganisms can survive treatment. The present study compared, through real-time polymerase chain reaction (qPCR), the effectiveness of TRUShape (TS) (Dentsply Tulsa Dental Specialties, Tulsa, OK) and Vortex Blue (VB) (Dentsply Tulsa Dental Specialties, Tulsa, OK) in removing Enterococcus faecalis (E. faecalis) from the mesial canals and isthmuses of mandibular molars. Fifty extracted human lower molars were inoculated with E. faecalis OG1RF for 14 days, and then an initial bacterial sample was collected with paper points from mesiobuccal and mesiolingual canals and isthmuses. The specimens were randomly divided into four groups (n = 10 teeth; 20 canals each), according to instrumentation system: TS 25/0.06, TS 30/0.06, VB 25/0.06 and VB 30/0.06. The remaining 10 teeth were divided between positive control, inoculated teeth without instrumentation or irrigation, and negative controls, teeth without inoculation. After instrumentation, the final sample was taken using paper points and DNA was isolated. Primers specific for E. faecalis were used for qPCR. The bacterial reduction between pre- and post-instrumentation was calculated. One-way analysis of variance (ANOVA) with Bonferroni's multiple-comparisons tests were for statistical analysis with significance of (p < 0.05). All file systems were able to reduce the load of E. faecalis from the prepared root canals, however, TS size 30 removed significantly more bacteria than size 25. Interestingly, regardless of the size, TS files removed significantly more E. faecalis biofilm (p < 0.05) than did VB files (63.7% vs 50.8% for size 25, and 69.5% vs 56% for size 30). In conclusion, when combined with irrigation, TS file system is more effective than VB in reducing E. faecalis biofilms from mesiobuccal and mesiolingual canals and the isthmuses of mandibular molars.

3-year Outcome of Patients with Persistent Pain after Root Canal Treatment: The National Dental Practice-Based Research Network.

INTRODUCTION: We measured the long-term outcomes of patients reporting persistent pain 6 months after root canal treatment (RCT) and assessed the characteristics differing patients with pain chronification from those with pain resolution. METHODS: Forty-five patients previously found to have persistent pain 6 months post-RCT from the National Dental Practice-Based Research Network were approached for a 3-year follow-up, and 27 participated in the survey. The frequency of self-reported pain, its impact on the ability to perform daily activities, and health care use were measured. The differences between patients whose persistent pain continued and those whose pain resolved were assessed. RESULTS: Five patients met criteria for pain at 3.4 years (range, 3.1-3.9 years) post-RCT, which was moderate in intensity, occurred for about 3 days in the preceding month, and kept 1 patient from usual activities. Additional health care was received by 4 of 5 patients whose pain continued compared with 7 of 22 patients whose pain resolved. A longer duration of preoperative pain and higher pain intensity and interference at 6 months were found among patients with pain chronification. Of 13 patients with specific diagnoses for the persistent pain derived at 65 ± 41 days (∼8 months) post-RCT, 10 improved regardless of the diagnosis or treatment, and 11 had a temporomandibular disorder and/or headache as comorbid diagnoses (6) or causes (6) of the persistent "tooth" pain. CONCLUSIONS: Progression of persistent post-RCT pain occurred in 19% of patients. The majority (56%) of patients improved without additional interventions. Both the group that improved and the group that continued to experience pain had a mixture of odontogenic and nonodontogenic etiologies.

Phenotypic and Genotypic Characterization of Streptococcus mutans Strains Isolated from Endodontic Infections.

Streptococcus mutans plays an important role in caries etiology and eventually in systemic infections. However, it is often found in infected root canals, but the pathophysiological characteristics of strains residing in this site are largely unknown. Here, we characterized strains of S. mutans isolated from root canals of primary (PI) and secondary/persistent (SI) endodontic infections in relation to serotype and genotype; presence of genes coding for collagen binding proteins (CBPs); collagen binding activity and biofilm formation capacity; ability to withstand environmental stresses; systemic virulence in Galleria mellonella; and invasion of human coronary artery endothelial cells and human dental pupal fibroblasts. Samples from 10 patients with PI and 10 patients with SI were collected, and a total of 14 S. mutans isolates, belonging to 3 genotypes, were obtained. Of these, 13 were serotype c, and 1 was serotype k. When compared with the reference strains, the clinical isolates were hypersensitive to hydrogen peroxide. Remarkably, all 14 strains harbored and expressed the CBP-encoding gene cbm, showing increased binding to collagen, enhanced systemic virulence in G. mellonella, and ability to invade human coronary artery endothelial cells and human dental pupal fibroblasts when compared with CBP-negative strains. Whole genome sequence analysis of PI and SI isolates revealed that these strains are phylogenetically related but genetically distinct from each other. Our findings highlight the importance of CBPs in facilitating colonization and persistence of S. mutans in collagenous substrates such as root canals and their potential role in the pathogenesis of endodontic infections.

The expression of heat shock protein 70 in the dental pulp following trauma.

BACKGROUND/AIM: Traumatic dental injuries vary in severity from mild concussion to avulsion. All organisms respond to stress by inducing the synthesis of a group of proteins known generically as heat shock proteins. The activation of these proteins is an essential cellular mechanism designed to protect against a variety of environmental stresses. It is probable that the production of these proteins is increased in the cells of the traumatized dental pulp, however, this has not as yet been demonstrated. The degree of heat shock proteins expression may be related to the severity of the trauma such that estimating the extent of heat shock proteins expression may provide a practicable way of quantifying these injuries. MATERIALS AND METHODS: Twenty adult male ferrets were divided into four groups. Each maxillary and mandibular right canine was traumatized with the contralateral canines acting as undamaged controls. The trauma was a simulated concussion injury applied using a uniform force. Animals were killed at 24, 48, 72 and 168 h after the injury. The canines were extracted, sectioned and processed for immunohistochemistry using a mouse monoclonal antibody specific for Hsp70. RESULTS: There was a statistically significant difference in Hsp70 staining between traumatized and non-traumatized teeth only in the group observed 24 h after the trauma. The expression of heat shock proteins form part of the early pulpal response to trauma.

Propolis inhibits osteoclast maturation.

Propolis, a natural product produced by the honey bee, has been successfully used in medicine as an anti-inflammatory and antimicrobial agent. Traumatic injuries to the teeth, especially avulsion injuries, present a challenging situation for the clinician because of post-treatment complications, such as inflammatory and/or replacement resorption. Agents that reduce osteoclast numbers and activity may be useful in the treatment of traumatic injuries to the teeth. In this study, we evaluated propolis as an anti-resorptive agent. Calcitriol-stimulated mouse marrow cultures, which contain both osteoclasts and osteoblasts, were exposed to the ethanol extracts of propolis or vehicle control and stained for tartrate-resistant acid phosphatase (TRAP)-activity to identify osteoclasts. A significant, dose-dependent reduction in multinuclear TRAP+ cells was demonstrated, although the propolis treatment accommodated cell growth and survival (P < 0.05). Propolis also reduced the formation of actin rings in pure cultures of RAW 264.7 osteoclast-like cells, suggesting that it exerts direct actions on osteoclast maturation. In summary, our data suggest that propolis inhibits late stages of osteoclast maturation including fusion of osteoclasts precursors to form giant cells and formation of actin rings. This supports the hypothesis that it may prove useful as a medicament to reduce resorption associated with traumatic injuries to the teeth.

Impact of Er,Cr:YSGG laser therapy on the cleanliness of the root canal walls of primary teeth.

Root canal therapy might be required for primary teeth displaying signs of pulpal inflammation or necrosis. Cleaning and shaping followed by obturation of the canal space with a resorbable paste have been widely performed with remarkable clinical success. However, lengthy endodontic procedures might be contraindicated when treating certain pediatric patients. The aim of this study was to compare the cleanliness of the root canal walls of primary teeth and the time required for the completion of the cleaning and shaping procedures performed by the Er,Cr:YSGG laser, manual or rotary instrumentation techniques. Thirty-five extracted, single-rooted, primary teeth were divided into 4 groups: I, canals were instrumented with Profile .04 rotary instruments to a master apical file size #35; II, the laser was used (parameters: 1.50 W, 20 pps, 30% water and 50% air) with a Z3 laser tip (0.32-mm diameter); III, canals were instrumented with stainless steel K-files; and IV, no instrumentation was performed (control). The teeth were split in 2 halves and prepared for scanning electron microscopy analysis. Images from the coronal, middle, and apical thirds of the roots were analyzed independently by 2 calibrated, blinded evaluators. Statistical analysis revealed significant differences among the groups (Kruskal-Wallis, P = .0001). The techniques were not capable of providing completely clean canals. Treatment with Er,Cr:YSGG laser provided similar cleanliness when compared with rotary instrumentation technique and was superior to manual instrumentation. The laser technique required less time for completion of the cleaning and shaping procedures when compared with both rotary or hand instrumentation.

Team-based learning using an audience response system: an innovative method of teaching diagnosis to undergraduate dental students.

A team-based learning (TBL) approach was used to facilitate student learning and performance in a sophomore preclinical endodontic course. TBL is based upon the division of a class into small groups of students using a problem-based learning approach. The purpose of this project was to improve student ability to diagnose diseases utilizing TBL combined with an audience response system (ARS). Three measures were used to assess the outcomes: 1) pre- and posttest scores, 2) a diagnostic skills assessment during the final examination, and 3) an attitudinal survey completed by the students. At the beginning of the course, second-year students (n=64) were evaluated to determine entry-level knowledge. Six groups of ten to eleven students each were pretested, followed by a parallel posttest following the implementation of the TBL experience. Students' performance on the posttest (63.4 percent) showed improved results when compared to the pretest (36.9 percent). Students also exhibited improved diagnostic skills with the final examination. The results of the students' attitudinal survey indicated an 80 percent agreement that TBL enhanced their powers of critical analysis.

Dental education economics: challenges and innovative strategies.

This article reviews current dental education economic challenges such as increasing student tuition and debt, decreasing funds for faculty salaries and the associated faculty shortage, and the high cost of clinic operations and their effect on the future of dentistry. Management tactics to address these issues are also reviewed. Despite recent efforts to change the clinical education model, implementation of proposed faculty recruitment and compensation programs, and creation of education- corporate partnerships, the authors argue that the current economics of public dental education is not sustainable. To remain viable, the dental education system must adopt transformational actions to re-engineer the program for long-term stability. The proposed re-engineering includes strategies in the following three areas: 1) educational process redesign, 2) reduction and redistribution of time in dental school, and 3) development of a regional curriculum. The intent of these strategies is to address the financial challenges, while educating adequate numbers of dentists at a reasonable cost to both the student and the institution in addition to maintaining dental education within research universities as a learned profession.

Obturation of root canal system treated by Cr, Er: YSGG laser irradiation.

The purpose of this study was to evaluate the number of canals and isthmuses obturated after Cr, Er: YSGG laser treatment. Fifty-two canals were instrumented to a size 40 Profile 0.06 file combined with RC-Prep and sodium hypochlorite, or sterile water. The teeth were divided into 3 groups: (I) canals were flooded with 17% ethylenediaminetetraacetic acid for 3 minutes, (II) canals treated with the laser for 40 seconds, and (III) received no further treatment. Obturation was done with System B and Obtura III and AH Plus sealer. The specimens were rendered transparent and evaluated for the number of canals/isthmuses obturated. The data were analyzed by Kruskal-Wallis test. The means +/- standard deviations for the groups were 17% ethylenediaminetetraacetic acid (1.14 +/- 0.8), laser (2.14 +/- 0.7), and control (0.4 +/- 0.8). Under the conditions of this study, Cr, Er: YSGG treatment resulted in a statistically significant greater number of canals/isthmuses obturated (P < .001).

A real time quantitative PCR analysis and correlation of COX-1 and COX-2 enzymes in inflamed dental pulps following administration of three different NSAIDs.

Dental pain is encountered daily by clinicians. Nonsteroidal anti-inflammatory drugs (NSAIDs) commonly used for pain management are traditionally cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibitors, and more recently selective COX-2 inhibitors. This study was designed to identify and quantify COX-1 and COX-2 gene expression level in inflamed rat molar pulps after administration of three NSAIDs: Celebrex, Vioxx, and Advil. Fifty male Wistar rats had their first and second molar pulps exposed and sealed with Cavit for 4 days. Rats were randomly divided into the three drug groups and two control groups. RNA was isolated from the rat pulps. Real Time Quantitative Reverse Transcriptase-Polymerase Chain Reaction assay, a relatively new PCR technique, was used to quantify COX-1 and COX-2 mRNA. Statistical analysis demonstrated no significant differences in COX-1 and COX-2 levels among the drug groups. However, Vioxx and Advil significantly reduced COX-2 expression levels compared to inflamed (positive control) pulps (p < 0.05).

The management of traumatic dental injuries.

Traumatic dental injuries are classified typically as luxation, avulsion, and horizontal root fracture injuries. However, the most confusing aspect of treatment is generally centered on luxation and avulsion injuries. As clinicians, it can be somewhat confusing as to which regime is the most appropriate treatment, since there are a variety of guidelines and treatment modalities.

The management of traumatic dental injuries.

Traumatic injuries require a vast and complex treatment methodology. This manuscript although in a "cookbook" format will still require from the practitioner sound clinical judgment prior to treating a traumatized tooth.

A comparison of two gutta-percha obturation techniques to replicate canal irregularities in a split-tooth model.

OBJECTIVE: The purpose of this study was to compare a modified injectable gutta-percha (MIGP) obturation technique with continuous wave technique (CWT) for the ability to fill the root canal system (RCS) and replicate artificially created intracanal defects at the apical third, using a split-tooth model. STUDY DESIGN: A maxillary canine was use to build a split-tooth model. The root canal was cleaned and shaped using crown-down technique with rotary files to size #40 at the apex. Intracanal defects were created in the dentin of the root canal walls with a half-round bur at the apical third. The canal was obturated 48 times with gutta-percha and sealer. Twenty-four obturations were performed for each technique, MIGP and CWT. After each obturation, the model was separated in 2 halves; buccal and lingual. Each obturation was examined and photographed under operating microscope at ×5 magnification. The images were blindly evaluated by 2 endodontists for the length of gutta-percha fill, ability to fill the RCS, presence of voids, and replication of the canal defects. RESULTS: Results were analyzed with the Mann-Whitney U test and showed statistical difference between the 2 groups in the quality of the obturation (P < .05). CONCLUSIONS: The MIGP technique appeared to replicate the canal defects at the apical third better than CWT, with fewer voids in between the canal walls and the gutta-percha mass.

A comparative evaluation of the sealing ability of 2 root-end filling materials: an in vitro leakage study using Enterococcus faecalis.

OBJECTIVE: The purpose of this study was to evaluate the sealing ability of EndoSequence Bioceramic Root-end Repair (BCRR) material when compared with white mineral trioxide aggregate (WMTA). STUDY DESIGN: Forty single-rooted teeth were instrumented, obturated with gutta-percha, root-end resected, and retrofilled with 2 different materials: white ProRoot MTA (WMTA) (n = 15) and BCRR (n = 15). Unfilled specimens (n = 10) received no retrofill and were used as controls. All groups received E. faecalis in a created reservoir coronal to the root filling and the presence of microleakage was evaluated by counting the colony-forming units from each specimen. The results were analyzed with 1-way analysis of variance. RESULTS: There was no significant difference in leakage between the 2 experimental groups, but there was a significant difference with the control (P ≤ .05). CONCLUSIONS: This study suggests that BCRR is equivalent in sealing ability to WMTA when used as root-end filling material in vitro.

Effect of propolis on proliferation and apoptosis of periodontal ligament fibroblasts.

The most critical factors affecting the prognosis of an avulsed tooth are extraoral dry time and storage media used before replantation. Studies have analyzed different storage media to determine the ideal solution to preserve periodontal ligament (PDL) cell viability. Propolis has anti-inflammatory and antimicrobial properties, and has been previously suggested as a storage medium. The purpose of this study was to assess not only cell viability but also physiological health of PDL cells after exposure to propolis. PDL cells were exposed to different concentrations of propolis or Hanks balanced salt solution, and the apoptotic levels were determined using apoptosis assay and flow cytometry. Additional cell viability and proliferation were analyzed by XXT assay in dry and wet conditions. Propolis not only decreased apoptosis but also increased the metabolic activity and proliferation of PDL cells. This study suggests that propolis is a suitable storage medium for avulsed teeth.