Background: Mesoporous calcium-silicate nanoparticles (MCSNs) have good prospects in the medical field due to their great physicochemical characteristics, antibacterial activity and drug delivery capacity. This study was to analyze the antibiofilm activity and mechanisms of silver (Ag) and zinc (Zn) incorporated MCSNs (Ag/Zn-MCSNs) with different percentages of Ag and Zn. Methods: Ag/Zn(1:9, molar ratio)-MCSNs and Ag/Zn(9:1, molar ratio)-MCSNs were prepared and characterized. Endocytosis of nanoparticles by Enterococcus faecalis (E. faecalis) treated with Ag/Zn-MCSNs was observed using TEM to explore the antibacterial mechanisms. The antibiofilm activity of Ag/Zn-MCSNs with different ratios of Ag and Zn was tested by E. faecalis biofilm model in human roots. The human roots pretreated by different Ag/Zn-MCSNs were cultured with E. faecalis. Then, SEM and CLSM were used to observe the survival of E. faecalis on the root canal wall. Cytotoxicity of the nanoparticles was tested by CCK8 kits. Results: The Ag/Zn-MCSNs release Ag⁺ and destroy the cell membranes to kill bacteria. The MCSNs containing Ag showed antibacterial activity against E. faecalis biofilms in different degrees, and they can adhere to dentin surfaces to get a continuous antibacterial effect. However, MTA, MCSNs and Zn-MCSNs could not disrupt the bacterial biofilms obviously. MCSNs, Ag/Zn(1:1, molar ratio)-MCSNs and Ag/Zn(1:9)-MCSNs showed no obvious cytotoxicity, while Ag-MCSNs and Ag/Zn(9:1)-MCSNs showed cytotoxicity. Zn-MCSNs can slightly promote cell proliferation. Conclusion: Ag/Zn-MCSNs have good antibiofilm activity. They might achieve an appropriate balance between the antibacterial activity and cytotoxicity by adjusting the ratio of Ag and Zn. Ag/Zn-MCSNs are expected to be a new type of root canal disinfectant or sealer for root canal treatment.

This study aimed to investigate the factors affecting the success rate of full pulpotomy in permanent posterior teeth with pulpitis. The study included 105 permanent posterior teeth clinically diagnosed as reversible or irreversible pulpitis in 92 patients aged 18–82 years. All teeth underwent a full pulpotomy using mineral trioxide aggregate as a capping material and were recalled for clinical and radiographic evaluation at 3, 6, 12, and 24 months postoperatively. The overall success rate after the 12-month review was above 90%, and failed cases mainly occurred during the first 12 months after treatment. In this study, the treatment outcome of pulpotomy was not related to sex, or tooth position and the cause of pulpitis. To analyze the influence of age on the treatment outcome, all the teeth were allocated to three groups: group 1 (18–39 years); group 2 (40–59 years); and group 3 (≥ 60 years). A significant difference in success rate was found between groups 1 and 3 (P = 0.014). These results suggest that pulpotomy can be used as an alternative treatment for permanent mature teeth diagnosed with pulpitis and that aging is one factor affecting the treatment outcome.

Background: Guided endodontics is a successful technique that has been gradually applied to endodontic therapy in recent years without being affected by the operator’s experience. However, the guided bur produces excessive heat during continuous rotation and friction with root canal walls, it is not clear whether the degree of temperature increase may lead to the periodontal ligament and alveolar bone damage. Methods: A total of 58 teeth were used, of which 40 teeth were not grouped, all used to evaluate the accuracy. 40 single-rooted premolars were scanned using CBCT and an intra-oral scanner, and 3D-printed guided plates were made with the pre-designed access. A custom-made guided bur was used to prepare the access cavities. The postoperative CBCT data and pre-designed pathways were matched to evaluate the deviation between the planned and virtual paths. The other 18 teeth were randomly divided into three groups (ET20 and ProTaper F3 as the control group, guided endodontics as the test group), with 6 teeth in each group. The temperature changes on the root surfaces were inspected with a thermocouple thermometer. Results: The average deviation on the tip and the base of the bur was 0.30 mm and 0.28 mm (mesial/distal), and 0.28 mm and 0.25 mm (buccal/lingual). The average angle deviation was 3.62°. The mean root surface temperature rise of the guided endodontics group was the lowest (5.07 °C) (P < 0.05). Conclusions: The access cavity preparation performed with guided endodontics has feasible accuracy and low-temperature rise on the root surfaces. Due to the limitations of the study, whether it has high reliability and safety in clinical applications needs to be further studied in vivo.

This study aims to compare the biological characteristics of human dental pulp stem cells (hDPSCs) isolated from different-aged populations and examine the effects of Biodentine on proliferation and odonto/osteogenic differentiation of hDPSCs isolated from the elderly in vitro. hDPSCs were isolated from three different-aged populations: group A (≤18 years old), group B (19–59 years old), and group C (≥60 years old). The adhesion, proliferation, odonto/osteogenesis, and senescence were compared. The optimal concentration of aqueous Biodentine extract was determined by CCK-8 assay, alkaline phosphatase (ALP), and alizarin red staining (ARS). The effect of Biodentine on odonto/osteogenic gene and protein expression of hDPSCs in each group was evaluated by quantitative real-time PCR (QRT-PCR) and Western blot. hDPSCs were successfully isolated from three different-aged populations. Flow cytometry revealed that all isolated hDPSCs were positive for CD73 (>90%), CD90 (>90%), CD146 (<30%), and negative for CD45 (<1%). There existed an age-related decline in proliferation, odonto/osteogenic gene expression, and S-phase fraction (p < 0.05), an increase in senescence genes and p21 and p16 expression, and time needed for cell adhesion. Biodentine promoted hDPSC proliferation and mineralization in each group, particularly at a concentration of 0.2 mg/mL. Biodentine markedly enhanced odonto/osteogenesis-related gene and protein expression in each group (p < 0.05). hDPSCs can be obtained from populations of all ages. Though there is an age-related decline in their biological properties, hDPSCs from the elderly still maintain certain proliferation and multidirectional differentiation abilities. Biodentine can significantly promote the proliferation and odonto/osteogenic differentiation of hDPSCs isolated from the elderly over 60 years old, which could be considered a pulp capping material for vital pulp therapy in the elderly. Nevertheless, the efficacy of Biodentine in clinical application has to be further studied.

Objective: This study was performed to compare the removal efficacy of hard-tissue debris in mandibular first molars prepared to various apical sizes. Methods: The mesial root canals of 40 extracted mandibular first molars were prepared by rotary nickel-titanium files to an apical size of #25/0.04 (Group #2504), #30/0.04 (Group #3004), #35/0.04 (Group #3504), and #40/0.04 (Group #4004). Irrigation was performed with 5.25% NaOCl and 17% EDTA. Micro-computed tomography was used to scan the samples before and after root canal preparation. Remnant hard-tissue debris was identified, quantified, and visualized three-dimensionally using shape recognition and image superimposition analysis, and the debris was mapped to its location. Results: After preparation, 11.67%±2.99% of the root canals contained hard-tissue debris in Group #2504, 8.00%±2.71% in Group #3004, 7.17%±2.88% in Group #3504, and 4.51%±1.61% in Group #4004. The amount of accumulated hard-tissue debris was significantly less in Group #4004 than in the other groups. However, there were no significant differences between Groups #3004 and #3504. Conclusions: An increased final apical size resulted in significantly lower debris accumulation. However, no root canal in any group was completely free from hard-tissue debris, and debris was mostly found in the isthmus of the mesial root canals.