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The aim was to analyse the influence of an apical ledge on root canal disinfection. Forty‐four single‐rooted teeth were micro‐CT scanned and inoculated with Enterococcus faecalis. In Group S shaping was performed with ProTaper Next (PTN) up to X3 at working length (WL). In Group L an apical ledge was created with K‐Files #40 and shaping completed up to PTN X3. NaOCl 5% and EDTA 10% irrigant solutions were alternated. Confocal laser scanning microscope (CLSM) and viability staining were used to analyse the proportions of dead (red) and live (green) bacteria and penetration ability inside dentinal tubules. Data were analysed with the Mann–Whitney test with Bonferroni correction (p < 0.05). In Group L the amount of red fluorescence resulted significantly lower, and penetration ability was decreased in the apical and middle portion (p < 0.05). The presence of an apical ledge may negatively influence the disinfection both in the apical and middle third. [ABSTRACT FROM AUTHOR]

This study investigated variation in working length during multiple‐visit endodontic treatment. Patients (N = 106) with pulpitis or pulp necrosis, with or without apical periodontitis, were included. During the first appointment, glide path was performed with ProGlider and shaping with ProTaper Next. Working length was detected four times. Working length was then re‐recorded prior to filling during the second appointment and a 0.5 mm threshold was selected as the minimum clinically meaningful variation. A logistic regression model was used to evaluate the impact of tooth anatomy, preoperative pulp status, apical periodontitis and lesions of endodontic origin on working length variation. Working length varied between first and second appointments in 34% of patients. The presence of apical periodontitis was the only variable significantly associated with variation in working length (p = 0.011). These data suggest that working length should be re‐checked prior to root canal filling to prevent procedural errors. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the immediate and aged bond strength and interfacial nanolaekage of different adhesives and protocols on dental elements prepared with diamond burs and Er:YAG laser. Materials and Methods: Forty molar crowns were flattened and a standardized smear layer was created. Teeth were divided into two main groups according to the dentin cutting technique: 1. Er:YAG laser for 30 s at 30 Hz repetition rate, 250 mJ energy per pulse, and water spray irrigation set at level 8; and 2. diamond bur. Each group was then divided into subgroups according to the adhesive protocol: SG1: dentin etching for 15 s followed by universal adhesive application (All Bond Universal, Bisco); SG2: universal adhesive application (All Bond Universal); SG3: two-step self-etch adhesive application (Clearfil SE Bond 2, Kuraray Noritake); SG4: etching followed by 3-step etch-and-rinse adhesive application (Optibond FL, Kerr). After curing the adhesives, resin composite buildups of 4 mm were made and specimens were sectioned to obtain 1-mm-thick sticks in accordance with the μTBS test technique. Sticks were stressed to failure at baseline and after 6 months of storage in artificial saliva. Three teeth per group were prepared for nanoleakage interfacial analyses. Data were statistically analyzed with three-way ANOVA and Tukey's post-hoc test (p < 0.05).Results: A significant difference in bond strengths was found for treatment, aging, and adhesive protocol. Nanoleak age analysis showed higher marginal infiltration in Er:YAG-treated groups both at baseline and after aging. Conclusions: Surfaces prepared with diamond burs presented higher bond strengths than did those prepared with Er:YAG laser. Adhesive protocols and aging could influence the adhesive-dentin interface. Further studies are necessary to validate the results obtained. [ABSTRACT FROM AUTHOR]

Featured Application: Root canal shaping techniques influence patients' postoperative quality of life after a primary root canal treatment. The introduction of more flexible reciprocating instruments with different alloy and geometry could lead to a general improvement of the postoperative symptoms. Patient-centered outcomes are crucial to evaluate the quality of the root canal treatment. Postoperative pain is a frequent complication of root canal treatment. It could worse patients' quality of life (QoL) and it may be associated to several factors, including the shaping technique. The aim of the study was to compare the impact of WaveOne Gold (WOG) and WaveOne Classic (WOC) reciprocating instrumentation on postoperative QoL after single-visit primary root canal treatment. Healthy subjects with pulp necrosis on multirooted teeth were observed. Canal shaping was performed with WaveOne Gold Primary (n = 25) or WaveOne Classic Primary (n = 29) and canal filling was completed with a carrier-based technique. Mean and maximum scores for postoperative pain were assessed through a Visual Analogue Scale (VAS) and QoL indicators were evaluated with a self-assessment questionnaire based on a Likert scale. Postoperative pain curves were similar in both groups (mean pain p = 0.43; maximum pain p = 0.27) and quality of life indicators showed no significant differences (p > 0.05). There was a more favourable trend of QoL values in the WOG group, reaching statistical significance on day six posttreatment (p = 0.021). Within the limitations of the study, reciprocating instrumentation may have an impact on patients' QoL, but the innovative geometrical and alloy properties of the WaveOne Gold seemed to induce a faster resolution of the postoperative symptoms. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the occlusal wear of CAD/CAM materials in a simulated condition of bruxism. The null hypothesis is that wear rate is not affected by the material employed for dental restorations. Materials and Methods: 160 sound, extracted molars were selected. A standardized adhesive overlay preparation was performed in all specimens, except in the control group. An intraoral scanner (Cerec Omnicam) was employed to scan preparations. Specimens were then divided in 6 groups (n = 16) according to the material employed for the overlay fabrication: G1) sound teeth; G2) Cerasmart (GC); G3) E-Max CAD (Ivoclar); G4) Katana Zirconia (Kuraray); G5) Grandio Block (VOCO); G6) Venus Pearls (Kultzer). Overlays of 2 mm thickness were luted following a standardized adhesive procedure (3-step etch-and-rinse, Optibond FL, Kerr) and light cured with an LED lamp for 2 min (D-Light Pro, GC). After 24 h, specimens were scanned (True-Depth, 3M) and then submitted to cyclic fatigue tesingt: 500,000 cycles, 80 N, semicircular movement, 8 Hz (CS4.4, SD Mechatronik). Each study group underwent a chewing simulation run using a specimen from each of the other groups as the antagonist. After testing, specimens were scanned again. Obtained STL files were superimposed with Geomagic Software to calculate volume loss after fatigue, expressed in mm3. Data were statistically analyzed with ANOVA and Tukey's post-hoc test (α = 0.05). Results: ANOVA showed a significant difference between groups. The post-hoc Tukey test showed that ceramic materials (G3 and G4) induced an increased volume loss compared to the other tested materials to enamel (p = 0.00001). The lowest volume loss was observed when chewing was done with the same materials occluding. The enamel wear rate was significantly affected by the materials employed. Thus, the initial null hypothesis was rejected. Conclusion: The choice of materials for overlay restorations in bruxism patients should strongly depend on the materials present in the opposing arch. Ceramic materials induced heavy wear on natural enamel. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this in vitro study was to evaluate the effect of curing time on the mechanical properties of fiberpost luting cement. The null hypothesis was that curing time does not affect hardness and Young's modulus. Materials and Methods: 24 premolars were endodontically treated and a class II cavity with 1.5 mm residual wall thickness and an 8-mm-deep post space was prepared. Fiber posts were luted trough a standardized procedure: etch for 20 s; rinse for 20 s; rinse with ethanol for 30 s; universal adhesive application (UBQ, Kuraray); fiber post insertion (Rabilda, Voco) after luting cement (DC Core, Kuraray) placement in the post space. Samples were divided into 3 groups according to the curing time (n = 8 each): G1, no light; G2, 20 s; G3, 120 s. Light curing was performed with an LED lamp (Celalux 2, Voco) at 1000 mW/s with the tip placed in contact with the fiber post. The occlusal cavity was restored with a nanofilled resin composite (Filtek Supreme XTE, 3M). After 7 days, half of each group's samples were submitted to cyclic fatigue testing with a chewing simulator for 500,000 cycles at 50 N load, 2 mm excursion, under water (CS 4.4, SD Mechatronik). Samples were sectioned into 1-mm-thick slices perpendicularly to the long axis of the fiber post. Samples were tested with a Nanoindenter XP, equipped with a diamond Berkovich indenter and characterized by a theoretical force resolution of 50 nN and a theoretical displacement resolution lower than 0.01 nm. The loading displacement (P-h) curves were analyzed using the Oliver-Pharr method to obtain the Young's modulus and hardness. The data were analyzed with ANOVA (α < 0.05). Results: Young's modulus and hardness were not correlated with the curing time (p = 0.0623). Cyclic fatigue significantly reduced the luting cement's mechanical properties (p = 0.0001) except when 120 s curing time was performed. Conclusion: The null hypothesis was partially rejected since curing time significantly affect the mechanical behavior of luting cement. [ABSTRACT FROM AUTHOR]

Background: Haptics-enhanced virtual reality (VR-haptic) simulation in dental education has evolved considerably during the past decade, representing a promising resource of simulation-based training opportunities to support conventional practice. We aim to summarize current literature on the applications of VR-haptics in learning, practicing, and teaching dental education., Methods: A literature search was performed using PubMed, focusing on research articles published between January 2010 and January 2024. Out of the 667 articles that matched the search terms (dentistry, education, haptic, teaching, training, virtual reality), 105 were screened, and 42 were eligible for full-text reading and utilization. Findings from an ongoing educator survey on the use of VR-haptics in dental education have also been provided., Results: VR-haptic simulation has been shown to have a supportive role in dental simulation practice. Despite training within a digital world, hand skill transfer to the real world has been demonstrated, which affords educators more flexibility in how to train their students before and during traditional preclinical and clinical practical education. The individualized VR-haptic training and feedback help students in mastering essential working techniques, while also increasing engagement and motivation., Conclusions: VR-haptics-supported dental education can help students effectively address challenges during their preclinical and clinical training, as well as in their subsequent careers, and it may help mitigate some weaknesses of the current educational system. Validation is a key factor for the acceptance of VR-haptic simulators; thus, further research and verification are needed before VR-haptics could be considered a primary hand skill development method of learning in dental education. VR-haptic simulation may in the future be used as an assessment tool for the students' and clinicians' credentialing process., (© 2024 The Author(s). Journal of Dental Education published by Wiley Periodicals LLC on behalf of American Dental Education Association.)

Aim: The aim of the study was to achieve the endodontic treatment of a second maxillary molar with abnormal anatomy through cone-beam computed tomography (CBCT) analysis and three-dimensional (3D) printing., Background: A patient arrived referring recurrent abscesses, spontaneous pain, and the difficulty to eat properly; a diagnosis of tooth necrosis was made. The periapical X-ray showed an abnormal anatomy of the tooth., Case Description: The preoperative analysis of the tooth morphology was performed through CBCT analysis. The 3D scans were reconstructed through a dedicated software application (Mimics) to visualize the abnormal anatomy and detect the root canal morphology. Moreover, a 3D printed model was created to plan the clinical stage. Canal shaping was achieved with ProGlider and ProTaper Next techniques, and the root canal filling was performed with a carrier-based technique., Conclusion: The limits of this case were the low definition of the CBCT owned by the patient and the difficulties during the scouting of the canals due to the abnormal endodontic space complicated by narrow and flat canals. The software reconstruction allowed a 3D high-definition preclinical analysis of the tooth anatomy., Clinical Significance: Both digital analysis and printed models based on CBCT scans seemed fundamental to preclinically understand the abnormal endodontic anatomy.