Present status and future directions: Apexification

The success rate of apexification is primarily determined by multiple factors, including the material used, the size of the open apex compared to the length of the root, and the technique used in each case. The main objective of this review was to provide an update on the present management of open apex to identify factors and circumstances that may influence the success of apexification using different materials and techniques. Future research on apexification should focus on how to treat open apices with wide periapical lesions without surgery. Previously, the predictability of these parameters with non-surgical procedures was uncertain, but now, with the use of a dental operating microscope, it has become more predictable. Another reason could be that extra visits are no longer required due to major advances in the armamentarium and materials used for apexification.

Radiographic evaluation of teeth with pulp stones and pulp canal obliteration: characteristics, and associations with dental parameters

The study aimed to radiographically assess the characteristics of pulp stones (PS) and pulp canal obliteration (PCO) in teeth and examined their associations with various dental parameters such as caries, restorations, periodontal status, and age. This cross-sectional observational study was conducted at the Faculty of Dentistry, King Abdulaziz University between September 2022, and May 2023, involved 101 patients exhibiting 402 teeth with PS or PCO. Data were collected from periapical and bitewing radiographs, and analyzed by two calibrated dentists. Multiple dental parameters were assessed, including caries level, presence and level of restorations, periodontal condition, and age of the patient. The study population consisted of 62 females and 39 males, with an age range of 18-65 years. Inter- and intra-examiner reliability were high (Kappa = 0.88 and 0.98 respectively). PS were more commonly found in molars (81.2%), while PCO were presented in only 115 teeth (23%). Age significantly affected the type of calcification (p < 0.001), with PS more common in the 20-30 age group and PCO more common in individuals over 40. Presence of caries was significantly associated with the type of calcification (p = 0.013), but restoration was not. The majority of teeth with PS (76%) or PCO (93%) had healthy periodontium. Around 40% of teeth with PCO showed signs of periapical changes, a finding significantly different from those with PS (p < 0.001). Pulp calcifications were significantly associated with various dental parameters, including caries presence, age, and periodontal status. The findings provide crucial insights into the epidemiology and aetiology of pulp calcifications.

Deciphering 3D periodontal fibroblast-macrophage crosstalk in bioactive nanoparticle-guided immunomodulation for treating traumatic dental avulsion

Prolonged extra-oral period in dental avulsion is often associated with loss of viability of Periodontal fibroblasts (PDLF) and increased risk of ankylosis. Root surface treatment with bioactive agents to reduce the risk of ankylosis can be a potential strategy. The objective of the study was to investigate the impact of an engineered chitosan nanoparticles (CSNP), photosensitizer Rose Bengal (RB) functionalized CSNP (CSRB) and sustained dexamethasone (CSDEX) releasing CSNP for application in management of delayed replantation of avulsed teeth. The 3D PDLF-macrophage (Mϕ) collagen model was developed and exposed to LPS, MCSF, RANKL with and without CSDEX/CSNP. Immunofluorescence and cytokine analysis was done at 2 and 7 days to assess cellular interactions. Maxillary right incisors in male Wistar rats were extracted, exposed to extraoral dry or LPS for 1 h and treated with or without CSDEX/CSRB for 1 min before replantation. Rats were euthanized after 21 days for micro-CT, TRAP, and immunofluorescence analysis. CSDEX/CSNP treatment in 3D model significantly reduced CD80, NFATc1, STAT6 and increased CD206 and periostin expression (p < 0.05). TNFα, MMP9 was downregulated and IL10, TGFβ1, MMP2 upregulated with CSDEX/CSNP (p < 0.05). CSDEX/CSRB in animal study significantly reduced resorption, ankylosis, TRAP activity and osteocalcin expression and increased periostin (p<0.05). CSDEX demonstrated higher anti-inflammatory activity by downregulating TNFα, while CSNP upregulated TGFβ1, periostin, and downregulated MMP9. The combination of matrix stabilization with CSRB with periostin upregulation and sustained releasing CSDEX showed potential for hampering root resorption and ankylosis in dental avulsion.

Integrating Phosphate Enhances Biomineralization Effect of Methacrylate Cement in Vital Pulp Treatment with Improved Human Dental Pulp Stem Cells Stimulation

Vital pulp treatment (VPT) is crucial for preserving the health and function of the tooth in cases where the pulp tissue remains vital despite exposure. Various materials are introduced for this purpose. However, challenges such as low strength, high solubility, and tooth discoloration persist. Methylmethacrylate-based cement (MC) offers excellent sealing ability, feasibility, and mechanical properties, making it a promising alternative for VPT. Phosphate-based glass (PBG) has the potential to promote hard tissue regeneration by releasing key inducers, phosphorus (P) and calcium (Ca), for reparative odontogenesis. This study investigates PBG-integrated MC (PIMC) by characterizing its properties, assessing human dental pulp stem cell activity related to initial inflammatory adaptation and odontogenic differentiation, and evaluating hard tissue formation using an in vivo dog pulpotomy model. Results indicate that a 5% PBG-integrated MC (5PIMC) maintains the physicochemical properties of MC. Furthermore, 5PIMC demonstrates cytocompatibility, excellent expression of osteo/odontogenic markers, and resistance to inflammatory markers, significantly outperforming MC. Enhanced hard tissue formation is observed in the dental pulp of mongrel dog teeth treated with 5PIMC. These findings suggest that 5PIMC could be an optimal and suitable material for reparative odontogenesis through VPT.

Contrast-Enhanced Micro-CT Imaging of Murine Mandibles: A Multi-Method Approach for Simultaneous Hard and Soft Tissue Analysis

AIM

To develop and evaluate a novel multi-method micro-computed tomography (μCT) imaging protocol for enhanced visualization of both hard and soft tissues in murine mandibles, addressing the limitations of traditional imaging techniques in dental research.

MATERIALS AND METHODS

We employed a contrast-enhanced (CE) μCT imaging technique using Lugol's iodine as a contrast agent to visualize the intricate structures of murine mandibles. The protocol involved the combination of conventional μCT imaging as well as CE-μCT, including decalcification with EDTA, allowing for simultaneous assessment of hard and soft tissues. The method is compared with standard imaging modalities, and the ability to visualize detailed anatomical features is discussed.

RESULTS

The CE-μCT imaging technique provided superior visualization of murine mandibular structures, including dental pulp, periodontal ligaments and the surrounding soft tissues, along with conventional μCT imaging of alveolar bone and teeth. This method revealed detailed anatomical features with high specificity and contrast, surpassing traditional imaging approaches.

CONCLUSION

Our findings demonstrate the potential of CE-μCT imaging with Lugol's iodine as a powerful tool for dental research. This technique offers a comprehensive view of the murine mandible, facilitating advanced studies in tissue engineering, dental pathology and the development of dental materials.

Dynamic analysis of a NiTi rotary file by using finite element analysis: Effect of cross-section and pitch length

This study assessed stress distribution, maximum stress values and fatigue life of experimentally designed NiTi rotary files with different cross-sectional geometry and pitch length using finite element analysis (FEA). Four cross-sectional shapes (Convex triangle, S-shaped, Triple helix and Concave triangle) and two pitch lengths (2 mm and 3 mm) were tested in simulated root canals with curvatures of 30°, 45° and 60°. The FEA results indicated that convex triangle and triple helix geometries exhibited lower stress values compared to the S-shaped and concave triangle designs. Increasing the canal curvature angle resulted in higher stress values, with the S-shaped instrument showing the most significant increase (up to 12%). Instruments with shorter pitch lengths showed more even stress distribution enhancing fatigue life. The maximum stress was concentrated 5-8 mm from the tip, varying across cutting edges, with S-shaped sections experiencing the lowest forces but higher stress due to lower moments of inertia.

Undergraduate endodontic curricula across Canadian Dental Schools: A cross-sectional analysis

INTRODUCTION

This study aimed to evaluate and assess the degree of uniformity in endodontics education at the undergraduate level among Canadian dental schools. The objective is to enhance Canadian dental education programs to meet societal oral health needs while incorporating advancements in the field of endodontics.

METHODS

An online survey comprising 36 multiple-choice questions targeting the nature of endodontic teaching was conducted as our methodology. Participation was sought from directors of the undergraduate endodontics program at all ten Canadian dental schools in 2021 and 2022.

RESULTS

A remarkable 100% response rate and the findings revealed a certain level of consistency among Canadian schools concerning pedagogical and assessment methods, as well as the endodontic topics taught to undergraduate students. However, notable variations were observed in the equipment and materials utilized. This study serves as a fundamental reference for identifying future modifications to the undergraduate endodontics curriculum in Canada.

Comparative evaluation of the remaining dentin volume following instrumentation with rotary, reciprocating, and hand files during root canal treatment in primary molars: An ex vivo study

Background/purpose

The effectiveness of root canal treatments with different file systems in primary teeth is important in terms of clinical practice and the use of file systems that work with different principles in primary tooth pulpectomy is becoming widespread. The amount of remaining dentin in the coronal region of the root is important in terms of the prognosis of the tooth and the long-term success of the treatment in teeth that have undergone root canal treatment. The aim of this study was to evaluate the remaining dentin volume in the coronal part of the root after the use of rotary, reciprocating, and conventional hand files in primary tooth pulpectomy.

Materials and methods

A total of 30 primary molars were divided into three groups. In each group, the preparations were made with three different file types: WaveOne Gold, which works with reciprocating motion; TruNatomy, which works with rotational motion; and conventional hand files. The three-dimensional images were evaluated for remaining dentin volume in the 2-mm coronal part of the root. Group means were compared using one-way analysis of variance, and post hoc analyses were performed with the Tukey test.

Results

There was no statistically significant difference between the groups in terms of preoperative and postoperative dentin volume (P > 0.05). The mean difference after preparation was observed the most in the WaveOne Gold group and the least in the TruNatomy group. When the mean percentage differences were evaluated, it was observed that statistically significantly more dentin volume was preserved after the preparation with TruNatomy than with WaveOne Gold (P = 0.021).

Conclusion

In primary tooth pulpectomy, file systems working with rotational motion can be preferred over file systems working with reciprocating motion in preserving the amount of dentin in the 2-mm coronal part of the root.

Shaping ability of three instrumentation system in moderately curved canals: A micro-CT study

This study aims to compare the shaping ability of three systems using micro-computed tomography (micro-CT). Moderately-curved mesial canals of 36 mandibular molars were assigned to three groups (n = 24); Protaper Next (PTN, 0.25, 0.06), WaveOne Gold (WOG, 0.25, 0.07), TruNatomy (TRN, 0.25, 0.04), and instrumentation was performed. Pre- and post-micro-CT scans were obtained. Canal volume and surface, structure model index (SMI), centroid shift, canal transportation, and untouched canal were analyzed. One-way ANOVA and Student's t-test were used for statistics. There was no difference in SMI, centroid shift, and centering ability between the study groups (p > .05). Removed dentin and canal surface changes were lower in TRN, while untouched dentin walls were higher (p < .05). Cross-sections became more rounded (p < .05), but not significant between groups (p > .05). Considering the removed dentin by TRN, it can be used in critical dentin thickness, such as the danger zone (DZ). PTN, WOG, and WOG kept the original canal course similarly. Untouched dentin by TRN (41%) was wider than PTN and WOG, consequently, meticulous irrigation is recommended. TRN, which provides a controlled increase in canal volume, can be used in thin dentin such as the DZ, however, its use should be supported by copious irrigation and brushing considering the rate of untouched dentin walls. RESEARCH HIGHLIGHTS: TRN presented a higher untouched dentin wall compared to PTN and WOG. Canal volume and surface changes were the lowest in the TRN group. The centering abilities were similar in PTN, WOG, and TRN.

Tissue engineering approaches for dental pulp regeneration: The development of novel bioactive materials using pharmacological epigenetic inhibitors

The drive for minimally invasive endodontic treatment strategies has shifted focus from technically complex and destructive root canal treatments towards more conservative vital pulp treatment. However, novel approaches to maintaining dental pulp vitality after disease or trauma will require the development of innovative, biologically-driven regenerative medicine strategies. For example, cell-homing and cell-based therapies have recently been developed in vitro and trialled in preclinical models to study dental pulp regeneration. These approaches utilise natural and synthetic scaffolds that can deliver a range of bioactive pharmacological epigenetic modulators (HDACis, DNMTis, and ncRNAs), which are cost-effective and easily applied to stimulate pulp tissue regrowth. Unfortunately, many biological factors hinder the clinical development of regenerative therapies, including a lack of blood supply and poor infection control in the necrotic root canal system. Additional challenges include a need for clinically relevant models and manufacturing challenges such as scalability, cost concerns, and regulatory issues. This review will describe the current state of bioactive-biomaterial/scaffold-based engineering strategies to stimulate dentine-pulp regeneration, explicitly focusing on epigenetic modulators and therapeutic pharmacological inhibition. It will highlight the components of dental pulp regenerative approaches, describe their current limitations, and offer suggestions for the effective translation of novel epigenetic-laden bioactive materials for innovative therapeutics.

Periapical surgery and different root obturation protocols for upper central incisor: A finite elements analysis

BACKGROUND

The aim of this study was to determine the effect of root canal filling using different obturation materials combined with apicoectomy in upper central incisors under loading with 1 N and 100 N. The effect of incomplete root formation was also investigated.

METHODS

Based on a CBCT-scan, a model of an upper central incisor was created. The model was altered to simulate different clinical situations: root canal treatment, apicoectomy at two different lengths and with different obturation protocols, and immature root formation after trauma. In each model the tooth was loaded with 1 and 100 N, and peak Von Mises stress of bone and tooth, elastic strain of the periodontal ligament, as well as rotation and displacement of the tooth were measured.

RESULTS

Periapical surgery increases stress in dentin and the surrounding bone. Different obturation materials only produce minor differences in a coronally intact tooth.

CONCLUSIONS

Interincisal angle or loading direction strongly affects all measured values and needs to be considered when planning periapical surgery or comparing finite element analysis. Immature roots show the highest stress values in this study, reaching half the yield strength of dentine.

Developing evidence-based clinical imaging guidelines for the diagnosis of vertically fractured teeth

OBJECTIVES

This study aimed to develop an evidence-based clinical imaging guideline for teeth suspected with vertical root fractures.

METHODS

An adaptation methodology based on the Korean Clinical Imaging Guidelines (K-CIG) was used in the guideline development process. After searching for guidelines using major databases such as Ovid-Medline, Elsevier-Embase, National Guideline Clearinghouse, and Guideline International Network, as well as domestic databases such as KoreaMed, KMbase, and KoMGI, two reviewers analyzed the retrieved articles. The retrieved articles were included in this review using well-established inclusion criteria.

RESULTS

Twenty articles were identified through an online search, of which three were selected for guideline development. Based on these three guidelines, this study developed specific recommendations concerning the optimal imaging modality for diagnosing teeth suspected of vertical root fractures.

CONCLUSIONS

Periapical radiography is the preferred method for assessing teeth with mastication-related pain and suspected vertical root fractures. However, if intraoral radiographs do not provide sufficient information about root fractures, a small FOV CBCT may be considered. However, the use of CBCT in endodontically treated teeth is significantly constrained by the presence of artificial shading.

Prevalence of multiple roots and complex canal morphology in mandibular premolars among a selected Southern Egyptian sub-population: a CBCT-analysis

The mandibular premolars can pose a significant challenge in root canal treatment due to their complex canal system. This study investigated the prevalence of multiple roots and complex canal morphology of mandibular premolars in a selected Egyptian sub-population using cone beam computed tomography (CBCT). 283 CBCT scans (131 males, 152 females, age 18-70) included 1132 mandibular premolars (566 first, and 566 second premolars) were viewed for incidences ofvariation in root numbers and canal configuration according to Vertucci's classification. CBCT images were assessed by two endodontists, data were statistically analyzed using Fisher exact and Chi-square tests. The majority of first premolars (85.7%) exhibited a single root, whereas 14.7% had 2 roots with a significantly higher frequency in males (19.8%) than in females (9.5%) (P < .05). The most prevalent type was type I (57.8%), followed by type V (21.7%), while types II and VII made up only 1%. Types V and III were more prevalent among females, while males had a higher prevalence of types I and IV. In 2.5% of cases, mandibular second premolars were found to have 2 roots, with a higher incidence in males (P < .05). Type I canals were significantly more prevalent (90.8%) than other types, followed by type V (5.3%) (P < .05). A statistically significant gender correlation was found regarding root number and canal configuration. It is not uncommon to find mandibular first premolars with two roots in the southern Egyptian population, particularly in males. These observations may be valuable for dentists who treat Southern Egyptians, in Egypt and other countries.

Managing Vital and Nonvital Tooth Bleaching Among Endodontists and General Dental Practitioners: A Knowledge, Attitude, and Practice Study

Tooth bleaching has become increasingly popular in recent times. It is the preferred conservative approach for lightening discolored teeth. The primary objective of tooth bleaching is to whiten teeth using oxidizing chemicals that work on both enamel and dentin. The noninvasive nature of modern bleaching systems allow for effective treatment options that meet the high expectations of patients. The objective of this study was to investigate the knowledge, attitude, and practices of dental practitioners in South India for managing discolored upper front teeth. We created and distributed a structured, validated questionnaire about bleaching discolored anterior teeth to South Indian dental practitioners and analyzed the data. We found a statistically significant relationship between endodontists and general dentists in their preferences for isolation techniques, choice of materials for vital bleaching, management of intact nonvital teeth, and management of postbleaching sensitivity. Women exhibit a greater preference for teeth-whitening procedures than men, with 74% opting for whitening treatments. The predominant method for addressing tooth discoloration is bleaching, which makes up approximately 63.8% of the whitening procedures. In-office bleaching is the preferred method for both vital and nonvital bleaching procedures, demonstrating its widespread acceptance and preference among practitioners.

PIEZO1 activation may serve as an early tissue biomarker for the prediction of irradiation-induced salivary gland dysfunction

Irradiation (IR)-induced xerostomia is the most common side effect of radiation therapy in patients with head and neck cancer (HNC). Xerostomia diagnosis is mainly based on the patient's medical history and symptoms. Currently, no direct biomarkers are available for the early prediction of IR-induced xerostomia. Here, we identified PIEZO1 as a novel predictive tissue biomarker for xerostomia. Our data demonstrate that PIEZO1 is significantly upregulated at the gene and protein levels during IR-induced salivary gland (SG) hypofunction. Notably, PIEZO1 upregulation coincided with that of inflammatory (F4/80) and fibrotic markers (fibronectin and collagen fibers accumulation). These findings suggest that PIEZO1 upregulation in SG tissue may serve as a novel predictive marker for IR-induced xerostomia.

Postoperative pain of minimally invasive root canal treatment:a randomized clinical trial

This randomized clinical trial compared postoperative pain between a minimally invasive (MP) and conventional root canal treatment protocol (CP). A total of 170 mature permanent teeth (either with vital or necrotic pulp), were randomly assigned into two groups. In the CP group, ProTaper Gold (Dentsply Sirona, Ballaigues, Switzerland) and a continuous wave of condensation technique were used, whereas, in the MP group, TruNatomy (Dentsply Sirona), ultrasonic-assisted irrigation (UI), calcium hydroxide, and a sealer-based obturation technique were used. Patients recorded preoperative and postoperative pain using a 0-10 numerical rating scale (NRS) at 4 h, 1, 2, 3, 4, 5, 6, and 7 days after instrumentation and 1 day after canal obturation, respectively. There were no significant differences in pain intensity at any time points assessed between the two groups (p > 0.05). The occurrence of moderate/intense pain after instrumentation was significantly associated with preoperative periapical index (PAI) (p = 0.017) and NRS scores (p < 0.001). Preoperative pulp status (p = 0.009) and NRS score (p = 0.006) were identified as significant factors in the occurrence of moderate/intense pain after obturation. Instrumentation unequivocally reduced pain severity for both groups. The post-endodontic pain associated with the use of MP, combined with UI, Ca(OH)2, and calcium-silicate cement, did not differ from that of CP. Preoperative pain score, PAI, and preoperative pulp status were determined to be prognostic factors for postoperative pain.

The effect of ascorbic acid, QMix and other conditioning solutions on the bond strength of adhesively luted glass fiber-reinforced composite posts to root dentin, a laboratory study

PURPOSE

This study was designed to investigate the effect of post space conditioning with different solutions on the bond strength of glass FRC posts and evaluate the mode of resin failure.

METHODS

Sixty extracted human single rooted teeth were root filled using a resin sealer and suitable gutta-percha cones. Post spaces were prepared, and the teeth randomly allocated into 5 groups according to their irrigation regimens which included the following solutions: 17 % EDTA, 2 % CHX, 3 % NaOCl, 10 % ascorbic acid and QMix solutions. Post spaces were irrigated with 5 ml of the solution for 15 s and subsequently washed with distilled water and dried with paper points. Glass FRC posts were cemented into their spaces using a self-adhesive resin cement. The specimens were mounted in plexiglass molds using autopolymerizing acrylic resin. A universal testing machine was used to measure post retention at a crosshead speed of 2 mm/min. The results were analyzed by one-way ANOVA followed by Tukey HSD test (α = 0.05). Dislodged posts and post spaces were examined microscopically to evaluate retention failure.

RESULTS

The Ascorbic acid group exhibited the highest mean retentive strength value at 229 N, followed by QMix at 198 N, NaOCl at 186 N, CHX at 170 N, and EDTA at 124 N. The mean value of the ascorbic acid group was significantly higher than EDTA group, p = 0.012. The failure category was primarily mixed.

CONCLUSIONS

Rinsing post spaces with ascorbic acid exhibited significantly superior bond strength. The failure mode was mixed.

CLINICAL SIGNIFICANCE

Irrigating post spaces with ascorbic acid solution before luting FRC posts significantly improves their bond strength compared to irrigation with EDTA solution. Irrigation with QMix solution produced the second highest retentive strength but showed no statistical significance when compared to using ascorbic acid, NaOCl, CHX, or EDTA solutions.

An artificial intelligence grading system of apical periodontitis in cone-beam computed tomography data

OBJECTIVES

In order to assist junior doctors in better diagnosing apical periodontitis (AP), an artificial intelligence AP grading system was developed based on deep learning (DL) and its reliability and accuracy were evaluated.

METHODS

One hundred and twenty cone-beam computed tomography (CBCT) images were selected to construct a classification dataset with four categories, which were divided by CBCT periapical index (CBCTPAI), including normal periapical tissue, CBCTPAI 1-2, CBCTPAI 3-5, and young permanent teeth. Three classic algorithms (ResNet50/101/152) as well as one self-invented algorithm (PAINet) were compared with each other. PAINet were also compared with two recent Transformer-based models and three attention models. Their performance was evaluated by accuracy, precision, recall, balanced F score (F1-score), and the area under the macro-average receiver operating curve (AUC). Reliability was evaluated by Cohen's kappa to compare the consistency of model predicted labels with expert opinions.

RESULTS

PAINet performed best among the four algorithms. The accuracy, precision, recall, F1-score, and AUC on the test set were 0.9333, 0.9415, 0.9333, 0.9336, and 0.9972, respectively. Cohen's kappa was 0.911, which represented almost perfect consistency.

CONCLUSIONS

PAINet can accurately distinguish between normal periapical tissues, CBCTPAI 1-2, CBCTPAI 3-5, and young permanent teeth. Its results were highly consistent with expert opinions. It can help junior doctors diagnose and score AP, reducing the burden. It can also be promoted in areas where experts are lacking to provide professional diagnostic opinions.

Effect of polydatin on the viability and odontogenic differentiation of human dental pulp stem cells: An in-vitro study

Background/purpose

Various materials have been used to promote human dental pulp stem cells (hDPSCs) differentiation to produce dentin bridge formation with less-than-optimal results. Polydatin (PD), a naturally present material with osteogenic properties can be a promising material in the pulp regeneration/repair process. The aim of this study was to evaluate the effect of (PD) on the viability and differentiation of human dental pulp stem cells.

Materials and methods

PD effect on hDPSCs in terms of cellular viability, alkaline phosphatase (ALP) production, and messenger RNAs (mRNA) of odontogenic markers production using quantitative reverse transcription polymerase chain reaction (RT-qPCR) were evaluated. In addition, mineral deposits were detected with Alizarin red stain.

Results

The viable hDPSCs in the presence of 0.01 μM and 0.1 μM PD were significantly higher than the control on days 3 and 7, respectively. In addition, ALP activity of hDPSCs was significantly increased with 0.01, 0.1, and 1 μM of PD. In addition, increased expression mRNAs of ALP, osteocalcin (OC), osteonectin (ON), osteopontin (OP), Runt-related transcription factor-2 (RUNX-2), dentin sialophosphoprotein (DSPP), and dentin matrix protein-1 (DMP-1) was observed after PD treatment, however, the difference was not statistically significant. Furthermore, increased size of mineral deposits was observed with PD.

Conclusion

PD promoted the expression of markers associated with odontogenic differentiation and mineralized tissue deposition in hDPSCs.

Radiologic evaluation of associated symptoms and fractal analysis of unilateral dens invaginatus cases

OBJECTIVE

The aim of this study is to determine the age-based prevalence of dens invaginatus cases and to learn the radiologic findings. In addition, fractal analysis of the periapical regions of unilateral dens invaginatus cases and contralateral teeth was performed to determine the effect of possible microleakage on fractal dimension.

METHODS

A total of 136 patients (170 teeth) identified in panoramic radiographs taken for diagnostic purposes between January 2018 and December 2023 at our Department of Oral and Maxillofacial Radiology were included in the study. Data were analysed using IBM SPSS V23. The Chi-square test was used for comparing categorical variables between groups. The relationship between the FD values calculated around the apexes of the teeth with unilateral dens invaginatus and the contralateral teeth was analyzed by paired t test. A significance level of p < 0.050 was adopted.

RESULTS

The mean age of the cases was calculated as 28.1 (8-63) years. 66 (48.5%) of the cases were female, and 70 (51.1%) were male. The lateral incisor was the most affected tooth among these cases. Bilateral cases were observed in 34 patients. Type 2 was detected in 93 patients, Type 1 in 35 patients, and Type 3 dens invagination in 8 patients. Dens invaginatus cases were observed in 134 maxillary and 2 mandibular teeth. Periapical lesions were seen in 22 of these cases.

CONCLUSIONS

Dens invaginatus cases are a congenital anomaly encountered at any age. Early diagnosis is crucial to prevent the loss of pulp vitality due to these invaginations. It should be noted that these invaginations can affect both jaws. However, due to the prevalence of occurrence in the maxillary anterior teeth and asymptomatic nonvitality, particular attention should be paid to evaluating this region.

Oxidative damage analysis and cell viability of Drosophila melanogaster exposed to three different endodontic sealers: an in vivo and ex vivo study

The aim of this work was to evaluate the toxicological action of AH Plus (AHP), Bio-C Sealer (BCS), and EndoSequence BC Sealer (ESB), using Drosophila melanogaster as the model organism performing in vivo and ex vivo analysis. D. melanogaster were exposed for 10 days to three concentrations (5 mg/ml, 10 mg/ml, and 20 mg/ml) of AHP, BCS, and ESB sealers mixed with 10 ml of standard diet. During this period, the mortality of flies was evaluated. On the 11th day, the locomotor activity test was performed and the flies were euthanized for oxidative damage analysis (reactive species and lipid peroxidation) and cell viability (resazurin reduction). For the mortality curves evaluation, the log-rank test (Mantel-Cox) was used. For the analysis of other data, a one-way analysis of variance (ANOVA) was applied, followed by Tukey's post hoc test (α  =  0.05). Regarding mortality, there were no significant differences. The locomotor activity was reduced, mainly in the two highest concentrations of AHP and BCS. Besides, reactive species generation was bigger in the AHP 20 mg/ml group. AHP induced a lipid peroxidation increase in all three concentrations tested, when compared to other sealers. Considering cell viability, the two highest concentrations of AHP reduced this parameter; while in other sealers, viability was reduced only in the highest concentration. AHP showed changes in oxidative markers that led to greater damage to the flies.

In vitro evaluation of the accuracy of electronic apex locators and cone-beam CT in the detection of oblique root fractures

OBJECTIVES

This study aimed to compare the accuracy of cone-beam CT (CBCT) scanning and 3 different electronic apex locators (EALs) in the detection of simulated oblique root fractures (ORF) in different localizations.

METHODS

The study utilised a total of 80 human maxillary incisors, which were categorised into two groups based on the location of the ORF (apical and middle third of the root) formed on the buccal side of the root surface. The measurement of the distance between the incisal edge and the intersection of the ORF with the root canal was conducted using a stereomicroscope. This measurement is referred to as the actual working length (AWL). Additionally, three EALs-Dentaport ZX, EndoRadar Pro, and Propex II-were utilised to determine the electronic working length (EWL). Furthermore, CBCT images were employed to assess the distance, known as the CBCT working length (CWL). The differences were determined by subtracting AWL from EWL and CWL.

RESULTS

Based on the accuracy of the devices, there were no significant differences observed among Dentaport ZX, EndoRadar, Propex II, and CBCT measures in both the apical and middle third ORF groups, within the acceptable range of 0.5 and 1 mm.

CONCLUSIONS

The accuracy of Dentaport ZX, Propex II, and CBCT was higher in the middle third ORF group compared to the apical third ORF group, with a tolerance of 0.5 mm. However, there were no significant differences seen among the devices.

Impact of low-fusion gutta-percha cones used in variations of the continuous wave condensation technique with filling sealers based on bioceramic compounds on the quality of root canal filling

To evaluate the impact on the quality of filling with of low-fusion and conventional gutta-percha cones. Thirty-six maxillary canines were prepared and divided into three groups: I-conventional cone with Downpack at 200 °C at 4 mm from the WL; II-low-fusion cone with Downpack at 100 °C up to 4 mm from the WL; III-low-fusion cone with Downpack at 100 °C up to 7 mm from the WL. Temperature variations were measured in thirds on the external surface of the root. The bond strength was evaluated using the push-out test. The adhesive interface was analyzed by scanning electron microscopy. The bond strength and the temperature variation data were analyzed using analysis of variance and the failure type using the chi-square test. The low-fusion cone group with 7 mm Downpack showed higher bond strength (4.2 ± 2.7) compared with conventional cones (2.8 ± 1.6) and low-fusion cones with 4 mm Downpack (2.9 ± 1.6) (p < 0.05), with occurrence of a higher number of adhesive failures to the filling material and mixed failures. Relative to temperature variation, there was less temperature change in the apical third, in the low-fusion cone with Downpack 7 mm (1.0 ± 1.0) (p < 0.05). The use of low-fusion cones allowed the continuous wave condensation technique to be performed at a lower depth of Downpack at 100 °C at 7 mm, with less heating in the apical third, without compromising the quality of filling. Using gutta-percha cones with low fusion, which permits a lower condensation temperature and reduced Downpack depth, maintains the quality of filling, in order to minimize possible damage to the periapical tissues.

Chemical and physical properties of radiopaque Portland cement formulation with reduced particle size

This study compared the chemical and physical properties of an experimental radiopaque white Portland cement (REPC) with reduced particle size to ProRoot white mineral trioxide aggregate (WMTA). The particle size distribution of experimental Portland cement (EPC) was examined, and then nano-zirconium oxide (nano-ZrO) was added to produce REPC. Chemical analysis, initial setting time, pH values, and push-out bond strength were evaluated. Results showed that REPC had smallest particle size (354.5±26.45 nm), while PC had the largest (1,309.67±60.54 nm) (p<0.05). Differences in chemical composition were observed. REPC exhibited shorter setting time (32.7±0.58 min) compared to WMTA (131.67±2.89 min) and PC (163.33±2.89 min) (p<0.05). All groups showed alkaline pH (p<0.05). REPC demonstrated the highest push-out bond strength (22.24±4.33 MPa) compared with WMTA (15.53±3.26 MPa) and PC (16.8±5.43 MPa) (p<0.05). This cost-effective PC formulation reduced the setting time and increased the push-out bond strength while maintaining the alkaline properties of the original cements.

Applications of smart materials in minimally invasive dentistry - some research and clinical perspectives

OBJECTIVES

Dental caries is one of the most prevalent bacteria-induced non-communicable diseases globally. It is known to be the top oral health burden in both developing and developed nations. There is substantial literature on the disease process and there is still debate on the extent of caries removal needed and the adequacy of the materials available to restore the lost tooth structure. The current review discusses the disease process together with the contemporary management of the carious lesion and also presents substantial evidence on novel materials and techniques that make minimally invasive dentistry predictable.

METHODS

The written work presented shows the most relevant literature for the management of dental caries focusing on novel materials used in minimally invasive dentistry.

RESULTS

There is still much to learn about specific antimicrobial and caries prevention mechanisms of novel materials. Materials that respond to a single or a few stimuli remain "weakly intelligent" in the face of the complex microenvironment in the oral cavity. Engineered systems that combine artificial intelligence and chemical engineering, are expected to possess higher intelligence, self-healing capabilities as well as environmental adaptability, and may be future promising research directions.

SIGNIFICANCE

The targeted approach in managing dental caries will hopefully have a better clinical outcome. The strategies discussed are alternatives to the contemporary approach and will improve the clinical management.

Impact of restorative material on fracture behaviors of class II restoration in endodontically treated deciduous molars

The purpose of this study was to investigate the fracture behavior of endodontically treated (ET) deciduous molar when directly restored with different restorative materials in Class II (MO) cavities in comparison with permanent teeth. MO cavities were prepared with 2.4-2.5 mm and 1.9-2.0 mm in buccolingual width, and mesiodistal width of each cavity walls, respectively, followed by direct restoration with different materials: resin-modified glass ionomer cement (RMGIC), composite resin (CR), and composite resin containing 25% short glass-fiber (SFRC). All specimens were subjected to mechanical loading tests at a speed of 1 mm/min and evaluated fracture resistance and fracture modes. A one-way ANOVA followed by a Tukey multiple comparisons analysis was used. Deciduous-SFRC (3,310.5±396.2 N) were significantly higher fracture resistance than permanent-RMGIC (1,633.8±346.8 N) (p<0.001), and permanent-CR (1,400.0±381.3 N) (p<0.001). For the direct restoration of MO cavity after endodontic treatment, SFRC demonstrated its promising performance in load-bearing capacity and failure mode, especially in ET deciduous molars.

Morphology and root canal configuration of maxillary lateral incisors: a systematic review and meta-analysis

The purpose of this study was to explore maxillary lateral incisors (MxLI) intern morphology by analyzing existing literature. We searched five electronical databases (Cochrane, Embase, LILACS, Scopus, MEDLINE via PubMed) using keywords and predefined search terms. Additional studies were identified by cross-referencing and reviewing bibliographies of relevant articles. From 92 initial studies, 27 duplicates were removed, and 65 records screened. After full-text review and hand searching were 19 studies included. The most reported root canal configurations (RCC) of MxLI were Vertucci (Ve) I (1-1-1/1; 78.1-100%), Ve II (2-2-1/1; 0.2-5%), Ve III (1-2-1/1; 0.1-14.6%), Ve IV (2-2-2/2; 0.5%), and Ve V (1-1-2/2; 0.5-4.9%). A meta-analysis of six studies from Europe and Asia indicated sex-differentiated patterns in RCC prevalence: higher occurrences of Ve II (2-2-1/1; OR [95%CI] = 1.19 [0.51, 2.73]), Ve III (1-2-1/1; (OR [95%CI] = 1.72 [0.61, 4.85]), and Ve V (1-1-2/2; (OR [95%CI] = 2.95 [1.02, 8.55]) configurations were noted in males, whereas females predominantly exhibited Ve I (1-1-1/1; [95%CI] = 0.99 [0.97, 1.02]), and Ve IV (2-2-2/2; (OR [95%CI] = 0.11 [0.01, 2.02]). Examination methods varied, with cone beam computed tomography (CBCT) being most commonly (n = 11), followed by staining & clearing (n = 5), and radiographic analysis (n = 1). The predominant RCC in MxLI is type Vertucci I. CBCT is the most common method for assessing the morphology of root canals. However, up to 20% of cases may present with complex and sex-specific patterns, highlighting the need for clinicians to be aware of these differences to prevent complications during endodontic treatments.

Single- versus multi-visit approach for fragment reattachment in complicated crown-root fractures: a cohort study

BACKGROUND

Complicated crown-root fractures are a type of tooth fracture that involves the enamel, dentin, and cementum and accompanied by pulp exposure. The treatment of a complicated crown-root fracture is always challenging due to the difficulties in achieving a hermetic seal and a stable restoration with a fracture level close to the crestale bone level. This study aimed to evaluate and compare the efficacy of single-visit and multi-visit approaches for fragment reattachment in complicated crown-root fractures of anterior teeth.

METHODS

Two cohort consist of 10 adolescent patients in each group at both genders, who suffered from permanent anterior tooth complicated crown-root fracture were included. Fragment reattachment with root canal treatment was performed with either single or multiple-visit approach. Single visit fragment attachement combined with root cannel therapy was conducted in single-visit approach group immediately after injury. Fragment attachment, root cananel therapy and post resoration were performed during three times ' clinical visit in multi-visit approach group.

RESULTS

All the patients in both groups achieved satisfactory aesthetic results one year after fragment reattachment. Patients who underwent a multi-visit approach had a significantly shorter operative duration, less intra-operative pain and fatigue, slightly better periodontal health at an early stage, and a decreased incidence of temporomandibular joint disorders compared to those who underwent a single-visit approach. However, multiple visits approach may increase the risk of fragment detachment postoperatively.

CONCLUSION

Fragment reattachment a reliable but temporary technique for adolescent patients who have suffered from complicated crown-root fractures. Multi-visit approach showed similar effecacy to single-visit approach but with slightly less complications. The choose of these two merhos should depend on the specific patient situation and patient compliance.

TRIAL REGISTRATION

This prospective cohort study was retrospectively registered in Chinese Clinical Trial Registry (ChiCTR2300076811) on 19/10/2023.

Cutting efficiency of different dental diamond rotary instruments for sectioning monolithic zirconia and lithium disilicate crowns

BACKGROUND

The aim of this study was to determine the cutting efficiency of different diamond rotary instrument types for sectioning monolithic zirconia and lithium disilicate anatomical crowns.

MATERIALS AND METHODS

The study used 30 diamond rotary instruments divided into three groups: Zirconia cutting diamond bur (White Z), super coarse grit diamond bur (KBlack), and medium coarse grit diamond bur (KBlue); Two subgroups were assigned based on the crown materials including monolithic zirconia (5YSZ) and lithium disilicate (e.max) ceramics. The cutting efficiency was assessed by measuring the time required to fully section the crowns, followed by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) of the dental burs before use and after every sectioned crown. A three-way ANOVA examined the effects of bur type, material type, and sectioning stage. If interaction exists, one-way ANOVA was used to compare the different subgroups, followed by the Tukey post hoc test. The significance level was assigned at α ≤ 0.05.

RESULTS

The results exhibited various cutting efficiencies among diamond rotary instruments and ceramic crown materials. White Z demonstrated superior cutting efficiency of zirconia crown compared with KBlack and KBlue for the first cutting cycles (p ≤ 0.05); the results tend to be more comparable at the third cutting cycle. However, the super coarse diamond bur exhibited higher efficiency in cutting lithium disilicate crowns than white Z and KBlue burs through all three cutting cycles(p ≤ 0.05). The diamond bur-cutting efficiency diminished after each use, irrespective of the bur type or the crown material (p ≤ 0.05); this was represented by the reduction of carbon and increased nickel matrix ratio after each bur usage.

CONCLUSION

White Z diamond bur showed higher cutting efficiency of zirconia in the first two cutting cycles; super coarse diamond bur is more efficient for cutting lithium disilicate crown in all of the cutting cycles. The amount of diamond on the burs reduced after each use, with no great impact on the material type when sectioning lithium disilicate and 5YSZ crowns.

CLINICAL SIGNIFICANCE

This study provides valuable insights for dental practitioners in selecting the appropriate diamond rotary instrument for crown sectioning. Practitioners can minimize the risk of damage and reduce the time required for crown removal, improving patient outcomes.

Optimized protocol for collecting root canal biofilms for in vitro studies

Endodontic retreatment is often necessitated by several factors, including the persistence of microorganisms in the root canal system (RCS). Their complex organization in biofilms increases their pathogenic potential, necessitating new disinfection strategies. This study aimed to standardize a new in vitro protocol for collecting biofilm from the RCS. Thirty-four bovine incisors were used in the study, divided into two experimental groups with two collection steps each: (a) biofilm collection protocol and (b) absorbent paper points protocol. Twelve specimens from each group were selected for counting colony-forming units (CFUs), while eight specimens were prepared for scanning electron microscopy (SEM). Two additional specimens served as sterilization controls to ensure that experiments were free of contamination. The coronal region was removed and standardized at 15 mm. After preparation with ProTaper up to F5, the apical foramen was sealed with composite resin, and the roots were stabilized with acrylic resin in 1.5-mL Eppendorf tubes. The specimens were sterilized and inoculated with Enterococcus faecalis NTCT 775 every 24 h for 21 days. After this period, each group underwent biofilm collection protocols, and CFU and scanning electron microscopy (SEM) data were analyzed. The Shapiro-Wilk test was performed to assess the normality of log-transformed data, and the results indicated a normal distribution for all groups, allowing parametric testing. The Levene test was used to evaluate the equality of variances. The proposed biofilm collection method yielded significantly higher CFU counts compared with the absorbent paper points method, particularly when analyzed on a log₁₀ scale. An independent samples t-test confirmed a statistically significant difference between the two methods (p < 0.0001). The proposed protocol achieved an efficiency rate of 95.85 % ± 1.15 %, whereas the absorbent paper points protocol yielded a lower efficiency of 5.46 % ± 1.37 %. Therefore, the biofilm collection protocol proposed in this study proved to be more effective for biofilm removal from the RCS.

Digital Simulation and Designing of a Novel Osteotomy Guide for Autotransplantation in the Anterior Region

Autotransplantation of teeth (ATT) is a viable treatment option for replacing teeth lost due to various reasons. Periodontal ligament (PDL) on the donor tooth is one of the most crucial factors determining the success of ATT. To preserve the PDL during surgery and improve the success rate of ATT, digital dentistry has been applied to ATT. In this article, a digital workflow including surgical simulation, a three-dimensional (3D) replica fabrication, and a novel osteotomy guide design is introduced. Digital simulation of ATT on a patient's integrated model enables visualization of anatomical structures and the 3D position of the donor tooth prior to the actual surgery. The 3D-printed osteotomy guide allows the transfer of the direction and depth of the planned osteotomy into the intraoral environment. The 3D replica helps prepare the recipient site before the actual transplantation, which minimizes the extra-alveolar time of the donor tooth and decreases trauma during the try-in process. The proposed virtual planning and the use of the guide and the 3D replica can facilitate the surgical procedures while minimizing complications.

Spatial Abilities and Endodontic Access Cavity Preparation: Implications for Dental Education

INTRODUCTION

Access cavity preparation is a crucial step in root canal treatment but is one of the most complex procedures in the curriculum to learn, with students often reporting spatial orientation difficulties during drilling. The present study aimed to evaluate the influence of spatial abilities on the preparation of endodontic access cavities among third-year dental students.

MATERIALS AND METHODS

Students from Lyon dental faculty participated voluntarily. The mental rotation test (MRT) evaluated spatial ability. Students prepared access cavities on 3D-printed mandibular molars, subsequently scanned and assessed against eight evaluation points, including morphology, canal access, floor preservation and convergence angle. Principal component analysis (PCA) assessed dataset variations.

RESULTS

A total of 43 volunteers participated. PCA revealed two principal components accounting for 80.8% of variations: the first PC primarily consisted of MRT score (64.3%) and morphology (14.1%); the second comprised operative time (46.1%) and morphology (18.0%). There were significant differences in morphology based on MRT scores, but no correlation was found between other parameters.

DISCUSSION

Lower MRT scores were associated with larger cavity preparations, raising questions about potential curriculum adaptations to enhance spatial reasoning. The operative time was not correlated with higher MRT scores but did contribute to variations in cavity morphology.

CONCLUSION

Spatial abilities have a substantial impact on the quality of endodontic access cavity preparations; further studies should evaluate if the incorporation of 3D atlas exercises could be beneficial.

GDF11 promotes osteogenic/odontogenic differentiation of dental pulp stem cells to accelerate dentin restoration via modulating SIRT3/FOXO3-mediated mitophagy

BACKGROUND

Growth differentiation factor 11 (GDF11) is considered to be a potential molecular target for treating pulpitis. However, whether GDF11 regulates osteogenic/odontogenic differentiation of dental pulp stem cells (DPSCs) to mediate pulpitis process remains unclear.

METHODS

Lipopolysaccharide (LPS) was used to induce inflammation conditions in DPSCs. The levels of GDF11, sirtuin 3 (SIRT3), forkhead box O-3 (FOXO3), osteogenic/odontogenic differentiation-related markers were measured by quantitative real-time PCR (qRT-PCR) and western blot (WB). Immunofluorescence staining was used to measure mitophagy. Mitophagy-related proteins were analyzed by WB, and the levels of inflammation factors were examined using qRT-PCR, ELISA and immunohistochemistry. Alkaline phosphatase activity and alizarin red S intensity were evaluated to assess osteogenic differentiation. Acute pulp (AP) injury rat model was constructed to study the role of oe-GDF11 in vivo.

RESULTS

GDF11 was downregulated in LPS-induced DPSCs, and LPS suppressed osteogenic/odontogenic differentiation and mitophagy. GDF11 overexpression promoted osteogenic/odontogenic differentiation in DPSCs through the activation of mitophagy. Furthermore, GDF11 upregulated SIRT3 to enhance FOXO3 expression by inhibiting its acetylation. GDF11 ameliorated LPS-induced inflammation and promoted osteogenic/odontogenic differentiation in DPSCs via enhancing SIRT3/FOXO3-mediated mitophagy. Besides, GDF11 overexpression suppressed inflammation and promoted dentin repair in AP rat models.

CONCLUSION

GDF11 promoted SIRT3/FOXO3-mediated mitophagy to accelerate osteogenic/odontogenic differentiation in DPSCs, providing a novel target for pulpitis treatment.

Outcome of non-surgical root canal retreatment of teeth with persistent apical periodontitis treated with foraminal enlargement and 2% chlorhexidine gel: a retrospective cohort study

INTRODUCTION

Non-surgical root canal retreatment (NS-RCRT) becomes necessary when primary endodontic procedures fail. This study evaluates the efficacy of NS-RCRT using 2% chlorhexidine gel and foraminal enlargement techniques, aiming to assess whether these approaches enhance periapical healing outcomes and success rates compared to traditional NS-RCRT techniques reported in the literature.

METHODS

This retrospective cohort study analyzed 120 teeth diagnosed with persistent apical periodontitis, from 80 patients who underwent NS-RCRT between January 2014 and December 2018 at a specialist's private practice. Data were collected following the Preferred Reporting Items for Observational Studies in Endodontics (PROBE) 2023 guidelines. Periapical healing was evaluated using digital periapical radiographs by three calibrated examiners. The outcome of the treatment was analyzed through descriptive statistics and bivariate analyses, including the Chi-Square and Fisher's Exact tests. Treatment outcomes were deemed successful if they showed complete or incomplete repair and unsuccessful if no repair was observed.

RESULTS

The average follow-up period was 30 months. Under loose criteria, 92.50% (n = 111) of the teeth were categorized as successful, and 7.5% (n = 9) as unsuccessful. Bivariate analysis indicated that the radiographic restoration of apical transportation was the only factor that significantly influenced the outcome.

CONCLUSIONS

NS-RCRT performed in a single visit using the foraminal enlargement technique and 2% chlorhexidine gel demonstrated high success rates and may be an effective alternative to tooth extraction. This method promoted periapical healing and could significantly improve NS-RCRT protocols. Further prospective studies are recommended to corroborate these findings.

Investigation of the biocompatibility of various pulp capping materials on zebrafish model

Testing the biocompatibility of commercially available dental materials is a major challenge in dental material science. In the present study, the biocompatibility of four commercially available dental materials Mineral Trioxide Aggregate, Biodentine, Harvard BioCal-CAP and Oxford ActiveCal PC was investigated. The biocompatibility analysis was performed on zebrafish embryos and larvae using standard toxicity tests such as survivability and hatching rates. Comparative toxicity analysis of toxicity was performed by measuring apoptosis using acridine orange dye and whole mount immunofluorescence methods on zebrafish larvae exposed to the dental materials at different dilutions. Toxicity analysis showed a significant decrease in survival and hatching rates with increasing concentration of exposed materials. The results of the apoptosis assay with acridine orange showed greater biocompatibility of Biodentine, Oxford ActiveCal PC, Harvard BioCal-CAP and Biodentine compared to MTA, which was concentration dependent. Consequently, this study has shown that showed resin-modified calcium silicates are more biocompatible than traditional calcium silicates.

Effectiveness of supplementary antimicrobial procedures in disinfecting lateral canals as evaluated by a novel ex vivo analytical approach

This ex vivo study devised an analytical ex vivo method for infection/disinfection of simulated lateral canals located in the middle and apical segments of the root. The antibacterial effects of supplementary approaches were tested in this model. Extracted mandibular premolars had their main root canals enlarged and then two lateral canals (100 μm in diameter) were created in the root, one in the apical and the other in the middle portion. Micro-computed tomography was used for specimen selection and to confirm the quality of the simulated ramifications. The specimens were contaminated with a mixed bacterial culture from subgingival bacterial biofilm added to pure Enterococcus faecalis strain ATCC 29212 grown overnight, using special strategies to facilitate culture medium penetration within the lateral canals. The following procedures were tested for disinfection: NaOCl/passive ultrasonic irrigation (PUI), NaOCl/XP-endo Finisher, ozonated water/continuous ultrasonic irrigation (CUI), and NaOCl/conventional irrigation with 30-G needles (control). Bacteriological samples were taken from the main canal before (S1) and after (S2) each supplementary protocol, and also from each lateral canal after treatment (S3). DNA extracted from the samples was subjected to quantitative real-time polymerase chain reaction. All S1 main canal samples were positive for bacterial presence. Bacterial counts in the main root canal substantially decreased by 99.2% after PUI, 99.1% after ozone/CUI, 99% after XP-endo Finisher, and 96% in the control group (P < 0.01 for all groups). There were no significant differences between groups (P > 0.05). The same was observed when comparing the effects of the supplementary approaches in the apical and middle lateral canals (P > 0.05). Only a few lateral canals showed no detectable bacteria. The method proposed here proved effective for ex vivo infection/disinfection studies. All supplementary approaches induced a substantial bacterial reduction in the main canal, with no significant differences between them. However, in terms of lateral canal disinfection, none of the tested approaches showed significant effects when compared to the control group.

Comprehensive review of composition, properties, clinical applications, and future perspectives of calcium-enriched mixture (CEM) cement: a systematic analysis

This review aims to comprehensively explore calcium-enriched mixture (CEM) cement as a crucial biomaterial in dentistry/endodontics. With its growing clinical relevance, there is a need to evaluate its composition, chemical/physical/biological properties, clinical applications, and future perspectives to provide clinicians/researchers with a detailed understanding of its potential in endodontic procedures. Through systematic analysis of available evidence, we assess the advantages/limitations of CEM cement, offering valuable insights for informed decision-making in dental/endodontic practice. Our findings highlight the commendable chemical/physical properties of CEM cement, including handling characteristics, alkalinity, color stability, bioactivity, biocompatibility, sealing ability, and antimicrobial properties. Importantly, CEM cement has shown the potential in promoting regenerative processes, such as dentinogenesis and cementogenesis. It has demonstrated successful outcomes in various clinical applications, including vital pulp therapy techniques, endodontic surgery, open apices management, root resorption/perforation repair, and as an orifice/root canal obturation material. The efficacy and reliability of CEM cement in diverse clinical scenarios underscore its effectiveness in endodontic practice. However, we emphasize the need for well-designed clinical trials with long-term follow-up to further substantiate the full potential of CEM cement. This review serves as a robust reference for researchers/practitioners, offering an in-depth exploration of CEM cement and its multifaceted roles in contemporary dentistry/endodontics.

Teaching a new Obturation Technique in Preclinical Endodontic Training: Assessment of Student Learning Experience, Performance, and Self-Evaluation

INTRODUCTION

This study investigated the impact of implementing hydraulic condensation (HC) as a second obturation technique in the Endodontic Preclinical course for dental students trained in warm vertical compaction (WVC).

METHODS

A total of 70 students performed root canal treatment of two extracted molars; they performed the HC technique for the first time after a demonstration. The combination of the obturation technique (WVC or HC) and the type of molar (maxillary or mandibular) was randomly assigned, resulting in four groups (n=35). The students answered a questionnaire appraising their learning experience and completed a self-evaluation rubric. Masked instructors graded projects. Data was statistically analyzed (significance set at 5%).

RESULTS

Most of the students (91%) considered learning two obturation techniques relevant and considered it difficult to perform the downpack in molars (p<0.05). About half of the students (45.7%) responded that HC resulted in fewer errors and disagreed that WVC derives in a more homogeneous obturation; accordingly, 52.9% of the students selected the highest self-grading for HC obturations, while only 38.6% for WVC. No significant difference was found in the distribution of grades attributed by students and instructors (p>0.05). Students reported significantly higher levels of confidence for HC and difficulty for WVC (p<0.05). No difference was found between the techniques regarding the presence of voids. The presence of multiple errors was more frequent for WVC (p<0.05).

CONCLUSION

The findings indicate a positive learning experience and comparable performance among preclinical dental students in implementing HC as an alternative obturation technique.

Impact of different activation procedures on sodium hypochlorite penetration into dentinal tubules after endodontic retreatment via confocal laser scanning microscopy

BACKGROUND

Infected dentinal tubules are a possible source of bacteria that are responsible for the failure of root canal treatment. Therefore, disinfection of dentinal tubules by increasing the penetration of the irrigation solution is important for success in retreatment cases. This study utilized confocal laser scanning microscopy (CLSM) to assess and compare the impact of XPR, ultrasonic irrigation (UI) and sonic activation (SA) on NaOCl penetration into dentinal tubules following endodontic retreatment.

METHODS

A total of forty mandibular premolars were enrolled in this investigation. Following root canal preparation up to ProTaper X3 file (30/0.07), root canals were obturated with gutta-percha and bioceramic root canal sealer with single cone technique. The root canal filling materials were removed using ProTaper nickel-titanium rotary retreatment files until the working length was reached. The retreatment procedure was finalized using the ProTaper Next X4 (40/0.06). The teeth were divided into four groups based on the irrigation activation technique: control (conventional needle irrigation), SA, UI and XPR. During the final irrigation procedure, Rhodamine B dye was introduced to 5% NaOCl for visualization via CLSM. Subsequent to image acquisition, the maximum penetration, penetration percentage, and penetration area were calculated. Data were statistically analyzed using the Kruskal-Wallis, Friedman, and Bonferroni Dunn multiple comparison tests through R software (p < 0.05).

RESULTS

In the middle third, UI yielded a significantly higher penetration percentage than the control group (p < 0.05). The UI and XPR groups showed increased penetration percentages in the coronal and middle thirds compared with the apical third (P < 0.05). Maximum penetration was notably reduced in the apical third than in comparison with the coronal and middle thirds in all groups (p < 0.05). In the control, SA and XP groups, the penetration area was ranked in descending order as coronal, middle and apical (p < 0.05). Conversely, in the ultrasonic group, the penetration area was significantly lower in the apical third than in the middle and coronal thirds (p < 0.05).

CONCLUSIONS

UI enhanced the penetration percentage in the middle third of the root compared with that in the control group. XPR and SA showed no significant effect on NaOCl penetration following retreatment.

Material properties and finite element analysis of adhesive cements used for zirconia crowns on dental implants

This study aimed to evaluate the material properties of four dental cements, analyze the stress distribution on the cement layer under various loading conditions, and perform failure analysis on the fractured specimens retrieved from mechanical tests. Microhardness indentation testing is used to measure material hardness microscopically with a diamond indenter. The hardness and elastic moduli of three self-adhesive resin cements (SARC), namely, DEN CEM (DENTEX, Changchun, China), Denali (Glidewell Laboratories, CA, USA), and Glidewell Experimental SARC (GES-Glidewell Laboratories, CA, USA), and a resin-modified glass ionomer (RMGI-Glidewell Laboratories, CA, USA) cement, were measured using microhardness indentation. These values were used in the subsequent Finite Element Analysis (FEA) to analyze the von Mises stress distribution on the cement layer of a 3D implant model constructed in SOLIDWORKS under different mechanical forces. Failure analysis was performed on the fractured specimens retrieved from prior mechanical tests. All the cements, except Denali, had elastic moduli comparable to dentin (8-15 GPa). RMGI with primer and GES cements exhibited the lowest von Mises stresses under tensile and compressive loads. Stress distribution under tensile and compressive loads correlated well with experimental tests, unlike oblique loads. Failure analysis revealed that damages on the abutment and screw vary significantly with loading direction. GES and RMGI cement with primer (Glidewell Laboratories, CA, USA) may be suitable options for cement-retained zirconia crowns on titanium abutments. Adding fillets to the screw thread crests can potentially reduce the extent of the damage under load.

Exploring fiberglass post numbers for enhanced fatigue resistance in molars without coronary remnants

This study aimed to assess the fatigue resistance of molars lacking a coronary remnant, using zero, one, two, or three fiberglass posts. Forty caries/crack-free human molars with coronal portions removed at the pulp chamber floor were randomly allocated into four groups (n=10). Following endodontic treatment, posts (Whitepost DC/DC.E 0.5, 1.0, FGM) were silanized (silane agent, Angelus) and cemented with a resin cement (RelyX U200, 3M ESPE). Resin composite cores (Z350, 3M ESPE) were built, and metal crowns were fabricated and cemented using the same luting system. Samples underwent cyclic fatigue testing at 45°, applying load in the occlusal surface at 10 Hz and 100 N initial load for 10,000 cycles, with 50 N increments every 10,000 cycles until failure. Fatigue failure load and cycles for failure data were recorded and subjected to survival analysis through Kaplan-Meier and Mantel-Cox post hoc tests, and Weibull analysis. Fractography patterns of failed crowns were qualitatively analyzed. The group without posts exhibited the lowest fatigue performance (p < 0.05) for both fatigue failure load and cycles to failure. Superior fatigue performance was observed in the three-post group, followed by groups with one or two posts, corroborated by the Weibull characteristic strength parameter. Weibull moduli were similar among conditions. All specimens exhibited failure involving detachment of the restorative set (posts/core/crown) with a portion of the dental remnant, without tooth fracture. Thus, when restoring mandibular molars without crown remnants, the use of fiberglass posts promotes greater fatigue resistance to oblique loads.

Assessment of tooth discoloration induced by root canal filling materials in pediatric dentistry

This study investigated the potential for tooth discoloration of root canal filling pastes used in pediatric dentistry. Sixty bovine incisors were sectioned 2 mm apical to the cementoenamel junction and allocated into 6 groups (n = 10) according to the type of filling material used: G1- Zinc oxide-eugenol sealer; G2- Zinc oxide-eugenol and iodoform paste; G3- Calcium hydroxide (CH) and zinc oxide paste; G4- CH, zinc oxide, and iodoform paste; G5- CH and iodoform paste; and G6- Control. Polyethylene glycol 400 was used as a vehicle for CH-containing pastes. Color measurements were taken at specific intervals: preceding endodontic treatment (T0) and at successive points of 1 month (T1), 2 months (T2), 3 months (T3), and 1 year (T4) after the placement of the filling material. The color change (∆E) was calculated using the CIELab formula. Statistical analysis was performed using ANOVA, followed by Tukey's post hoc test (α = 5%). Significant differences were observed among the filling materials and time intervals (p <0.001). All groups exhibited color changes over time, except G1 and G5, which showed color changes only after 1 year. G1 and G2 demonstrated the highest ∆E values, with a statistically significant difference observed only at T2 when compared to G3 (p = 0.008). Root canal filling materials used in primary teeth have the potential to induce tooth discoloration.

Effects of minimally invasive endodontic access cavity in molar teeth on polymerization, porosity and fracture resistance

Minimally invasive access cavities have been proposed in the last decade to reduce tooth tissue loss during endodontic treatment and mitigate compromised fracture resistance of endodontically treated teeth. Fracture resistance of molars with different types of access cavity design may be affected by restorative materials and aging. Insufficient literature data exist on the effect of cavity design and type of restorative materials on restorative aspects such as material adaptation or photo-polymerization in restricted access cavities. This study analyses quality of polymerization, material adaptation and fracture resistance of molars with different types of access cavities restored with glass-ionomer, high-viscosity fiber-reinforced bulk-fill and nanofilled resin composite. Plastic molar teeth with truss (TREC) and traditional endodontic access cavity (TEC) were restored with nanofilled composite (Filtek Supreme), glass-ionomer Fuji IX and Filtek or fiber-reinforced everX Posterior and Filtek. Porosity was determined using microcomputer tomography and the degree of conversion of resin-based materals using micro-Raman spectroscopy. Human molars prepared and restored in the same way were used for fracture resistance testing at baseline and after thermocycling. The results demonstrate that high-viscosity fiber-reinforced composite was difficult to adapt in TREC cavity leading to greater porosity than Filtek or Fuji. TREC design did not affect composite polymerization and led to higher fracture resistance of restored molars compared to TEC but also more unrestorable fractures.

In Vitro Bond Strength of Dentin Treated with Sodium Hypochlorite: Effects of Antioxidant Solutions

This systematic review aims to evaluate whether the application of antioxidant solutions can enhance the bond strength of resin-based materials to sodium hypochlorite (NaOCl)-treated dentin. This study follows the PICOT strategy: population (sodium hypochlorite-treated dentin), intervention (application of antioxidants), control (distilled water), outcome (bond strength), and type of studies (in vitro studies). The systematic review and meta-analysis were conducted following PRISMA guidelines. Electronic databases were searched for in vitro studies evaluating the effects of antioxidants on bond strength to sodium hypochlorite-treated dentin. Two independent reviewers screened articles, extracted data, and assessed risk of bias. Meta-analyses were performed using a random-effects model to compare standardized mean differences in bond strength between antioxidant pretreatment and control groups. Inclusion criteria consisted of in vitro studies that examined the bond strength of resin-based materials to NaOCl-treated dentin with antioxidant application, while exclusion criteria included studies with incomplete data, those not using a control group, or those that did not directly measure bond strength. From 3041 initial records, 29 studies were included in the qualitative analysis and 25 in the meta-analysis. Ascorbic acid, sodium ascorbate, grape seed extract, green tea, and rosmarinic acid significantly improved bond strength to sodium hypochlorite-treated dentin (p < 0.05). The effectiveness of grape seed extract varied with adhesive system type. Hesperidin, p-toluene sulfonic acid, and sodium thiosulfate did not significantly improve bond strength. Most studies had a high risk of bias. This suggests that the conclusions drawn from these studies should be interpreted with caution, and further research with more robust methodologies may be needed to confirm the findings. In conclusion, this systematic review implies that certain antioxidants can improve bond strength to sodium hypochlorite-treated dentin, with efficacy depending on the specific agent and adhesive system used. Further standardized studies are needed to optimize protocols and confirm these findings.

Biocompatibility and antimicrobial effect of demineralised dentin matrix hydrogel for dental pulp preservation

Regeneration of dentin and preserving pulp vitality are essential targets for vital pulp therapy. Our study aimed to evaluate a novel biomimetic pulp capping agent with increased dentin regenerative activities. To produce demineralised dentin matrix (DDM) particles, human extracted teeth were ground and treated with ethylene diamine tetra-acetic acid solution. DDM particles were added to sodium alginate and this combination was dripped into a 5% calcium chloride to obtain DDM hydrogel (DDMH). The eluants of both DDMH and mineral trioxide aggregate (MTA) were tested using an MTT assay to detect their cytotoxic effect on dental pulp stem cells (DPSC). Collagen-I (COL-I) gene expression was analysed on DPSC exposed to different dilutions of pulp capping material eluants by real-time quantitative polymerase chain reaction. Acridine orange staining was used to monitor the cell growth over the tested materials. Agar diffusion assay was utilised to test the antibacterial effect of DDMH and MTA compared to controls. MTT assay revealed that neat eluates of DDMH promoted DPSC viability. However, neat eluates of MTA were cytotoxic on DPSC after 72 h of culture. Moreover, DPSC were capable of growth and attached to the surface of DDMH, while they showed a marked reduction in their number when cultured on the MTA surface for one week, as shown by the acridine orange stain. In DPSC cultured with DDMH eluates, the COL-I gene was overexpressed compared to those cultured with MTA eluants. DDMH had significant antimicrobial activity in comparison to MTA after 24 h incubation. This in vitro study showed that DDMH could be an alternative pulp capping agent for regenerative endodontics.

Antibiotic Prescribing Habits in Endodontics among Dentists in the Federation of Bosnia and Herzegovina-A Questionnaire-Based Study

BACKGROUNDS

Antibiotics are used in endodontic treatment to control acute odontogenic infection and for prophylactic purposes. This study aimed to investigate the knowledge of dentists from the Federation of Bosnia and Herzegovina about the choice and the routes of antibiotic administration in endodontics.

METHODS

This cross-sectional study involved dentists in Federation of Bosnia and Herzegovina health institutions. The Dental Chamber sent a twelve-question survey to members' email addresses. They were asked about the type, dosage, indications, and side effects of antibiotics used in endodontics. The obtained data were screened and analyzed.

RESULTS

A total of 180 questionnaires were filled out. The most commonly prescribed antibiotic was amoxicillin with clavulanic acid. Pulp necrosis with symptomatic apical periodontitis, swelling, and moderately severe symptoms were the main indications for the therapeutic use of antibiotics. Amoxicillin, administered orally at 2 g 1 h before endodontic surgery for patients with bacterial endocarditis, was mostly indicated for the prophylactic use of antibiotics.

CONCLUSIONS

Based on the results of this study, we can conclude that dentists from the Federation of Bosnia and Herzegovina have limited knowledge regarding antibiotic use in endodontics. Educational activities and campaigns are necessary to raise awareness about antibiotics in dental medicine in the Federation of Bosnia and Herzegovina.

Evaluating the Impact of Ultrasonic Irrigation on Bacterial Levels and Activity Following Chemomechanical Procedures

AIM

This single-arm interventional trial aimed to investigate the efficacy of ultrasonic irrigation as a supplementary disinfection approach after chemomechanical procedures using molecular techniques based on ribosomal RNA (rRNA) and rRNA genes (referred to as DNA).

METHODOLOGY

Samples were collected from 35 single-rooted teeth with radiographic evidence of apical periodontitis. Samples were taken after gaining root canal access (S1), chemomechanical procedures (CMP, S2), and ultrasonic irrigation (S3). DNA-targeted qPCR using universal primers was used to estimate total bacterial levels, while rRNA-targeted qPCR was used to assess bacterial activity. Ratios between rRNA and DNA levels were calculated to search for active bacteria in the samples (rRNA/ DNA ≥ 1). Wilcoxon matched-pairs signed-rank test was used to compare the differences in DNA levels between samples and DNA and rRNA levels within samples (P <.05).

RESULTS

DNA-based methods revealed a significant decrease in bacterial levels from S1 to S2 and S2 to S3 (both P <.05). Notably, 11 out of 35 (31.4%) root canals did not harbor bacterial DNA after CMP, whereas ultrasonic activation increased DNA-negative samples to 17 (48.6%). However, all DNA-positive samples were also positive for rRNA, with significantly higher rRNA than DNA levels (P <.05), indicating bacterial activity at the sampling time.

CONCLUSIONS

Ultrasonic irrigation improved the disinfection of root canals after chemomechanical procedures by reducing bacterial levels. However, persisting bacteria remained active in the root canals after CMP and ultrasonic irrigation.

Postoperative pain after total pulpotomy and root canal treatment in mature molars according to the new and traditional classifications of pulpitis: a prospective, randomized controlled trial

BACKGROUND

The aim of this study was to compare postoperative pain following total pulpotomy (TP) and root canal treatment (RCT) in mature molar teeth with irreversible pulpitis. To compare the traditional pulpitis classification system with the Wolters system in evaluating postoperative pain.

METHODS

Eighty mandibular molars with irreversible pulpitis were included and classified according to the Wolters (moderate/severe pulpitis). The teeth were randomly assigned to two groups (RCT or TP). RCT was performed following standardized protocols. TP was performed to the level of the canal orifices, and hemostasis was achieved with 2.5% sodium hypochlorite. A 3 mm layer of MTA was placed as the pulpotomy material. The teeth were restored with glass ionomer cement followed by composite. Pain scores were recorded preoperatively and, at 6, 12, 24, 48, and 72 h and 7 days after the interventions. The data were statistically analyzed using the Mann-Whitney U test, the Friedman test, the Wilcoxon signed-rank test, and the Spearman's correlation test. The significance level was set at 0.05.

RESULTS

Sixty-four patients were analyzed at the one-week follow-up and all were diagnosed as irreversible pulpitis according to the AAE; 22 teeth were classified as moderate and 42 teeth were classified as severe pulpitis according to Wolters. There was no significant difference between TP and RCT in pain scores in moderate pulpitis patients (p > 0.05). There was a significant difference between TP and RCT at 24 and 72 h of severe pulpitis; higher pain scores were observed in the RCT (p < 0.05).

CONCLUSIONS

In patients with moderate pulpitis, the TP procedure allowed symptom relief more quickly than RCT. In patients with severe pulpitis, TP provided for significantly lower pain scores compared to RCT at both 24 and 72 h.

CLINICAL TRIAL REGISTRATION

The study was retrospectively registered with ClinicalTrials.gov (NCT05923619). Date of Registration: 06/16/23.

Comparison between AH plus sealer and total fill bioceramic sealer performance in previously untreated and retreatment cases of maxillary incisors with large-sized periapical lesion: a randomized controlled trial

OBJECTIVE

This study aims to assess the efficacy of bioceramic (BC) sealer when applied using the single cone technique (SCT), in comparison to AH Plus sealer applied with the cold lateral condensation technique (LCT), concerning their impact on the healing of large-sized periapical lesions in both untreated and retreatment cases.

MATERIALS AND METHODS

A randomized controlled trial was conducted on 41 patients who had 60 permanent teeth in the maxillary incisors that were accompanied by large-sized periapical lesions. The included teeth were radiographed with cone beam computed tomography (CBCT) images and divided equally into two groups according to the endodontic treatment statute (30 untreated previous cases and 30 retreated cases). Subsequently, teeth received uniform preparation, irrigation, and dressing procedures. Then each group was divided equally according to the used sealer (15 teeth obturated using AH plus sealer with LCT and 15 teeth obturated using BC sealer with SCT). All cases were followed up after 6 and 12 months with CBCT images. Subsequently, the change in periapical lesion diameter (PLD) was observed as an indicator to determine the treatment outcome score. One-way ANOVA and Mann-Whitney U test were used to analyze the PLD changing and scoring the treatment outcome during the follow-up periods. The significance level was set at α = 0.05.

RESULTS

There were no statistically significant differences between untreated and retreatment cases neither using AH plus sealer with LCT nor BC sealer with SCT regarding changes in PLD in the follow-up periods. Moreover, there were no significant differences between groups regarding treatment outcome scores in the follow-up periods. All groups showed a high success rate.

CONCLUSIONS

Successful treatment was achieved for untreated or retreatment maxillary incisor cases accompanied by large-sized periapical lesions using either BC sealer with the SCT or AH Plus sealer with LCT with a similar high success rate up to 12 months follow-up period.