Abstract: 

Regenerative endodontics (REP) is a new clinical modality aiming to regenerate damaged soft and hard dental tissues, allowing for root completion in young adults’ teeth. Effective disinfection is crucial for REP success, but commonly used antimicrobials often harm the niche dental pulp stem cells (DPSCs). To our knowledge, this is the first study to explore the biocompatibility and antimicrobial potential of pectin as a potential natural intracanal medicament for REPs. Low methoxyl commercial citrus pectin (LM) (pectin CU701, Herbstreith&Fox.de) was used in all experiments. The pectin’s antibacterial activity against single species biofilms (E. faecalis and F. nucleatum) was assessed using growth curves. The pectin’s antimicrobial effect against mature dual-species biofilm was also evaluated using confocal laser scanning microscopy (CLSM) after 30 min and 7 days of treatment. The DPSC biocompatibility with 2% and 4% w/v of the pectin coatings was evaluated using live/dead staining, LDH, and WST-1 assays. Pectin showed a concentration-dependent inhibitory effect against single-species biofilms (E. faecalis and F. nucleatum) but failed to disrupt dual-species biofilm. Pectin at 2% w/v concentration proved to be biocompatible with the HDPSCs. However, 4% w/v pectin reduced both the viability and proliferation of the DPSCs. Low concentration (2% w/v) pectin was biocompatible with the DPSCs and showed an antimicrobial effect against single-species biofilms. This suggests the potential for using pectin as an injectable hydrogel for clinical applications in regenerative endodontics

ABSTRACT

Objectives: This research aims to evaluate the comparative efficacy of calcium hydroxide combined with silver nano-particles and conventional calcium hydroxide as intra-canal medications following non-surgical root canal retreatment in reducing post-operative pain. 

Materials and Methods: A randomized, prospective, parallel, triple-blind clinical trial was conducted with 120 medically healthy patients diagnosed with symptomatic apical periodontitis. All patients had previously undergone endodontic treatment on anterior or premolar teeth and were between 25 years and 50 years old. Participants were randomly and equally assigned to two groups based on the added solution; either nano-silver solution or distilled water. Opaque bottles containing the nano-silver solution or distilled water were covered and coded as either A or B by a dental assistant, who prepared the intra-canal medicament paste by mixing one of the solutions with calcium hydroxide (Ca(OH)₂) powder before providing it to the operators. Both operators and patients were blinded to the group assignments. Patients were assessed pre-operatively and at 6, 12, 24, and 48 hours post-operatively using the Numerical Rating Scale (NRS). Statistical analyses were conducted using the Mann-Whitney U test, Wilcoxon’s rank test, Friedman’s test, and chisquare (χ²) test. Additionally, relative risk (RR), relative-risk reduction (RRR), and 95% confidence intervals (CI) were calculated. 

Results: There was no statistically significant difference in post-operative pain incidence and intensity between the two groups at different time intervals. However, within the same group, pain intensity varied significantly over time (P<0.05). The relative risk (RR) of pain incidence and its 95% CI at 6, 12, 24, and 48 hours were: 6 hours: RR = 0.86 (95% CI: 0.63, 1.19), 12 hours: RR = 0.87 (95% CI: 0.54, 1.41), 24 hours: RR = 0.54 (95% CI: 0.23, 1.26), 48 hours: RR = 0.33 (95% CI: 0.07, 1.59). No adverse effects related to the tested materials were reported.

 Conclusions: Although the relative risk of pain incidence was lower in the treatment group than in the control group, the confidence intervals crossed 1, indicating no statistically significant difference. Further studies with larger sample sizes are needed to confirm these findings.

Regenerative endodontic procedures (REPs) which aim to promote root development and pulp tissue regeneration in necrotic immature teeth, have emerged as a promising therapeutic approach. A critical determinant of REP success hinges on effective disinfection of the root canal system, which must eliminate microbial contaminants whilst preserving the microenvironment necessary for dental pulp stem cell tissue regeneration. This study reports on the fabrication of biocompatible 3D printed hydrogel scaffolds designed for root canal disinfection. The scaffolds incorporate benzyldimethyldodecylammonium chloride (BDMDAC) a broad-spectrum quaternary ammonium compound characterised by low cytotoxicity and minimal risk of resistance development. BDMDAC loaded gelatin biomaterial inks were systematically evaluated for rheology properties, mechanical stability and drug release properties. Scaffolds containing 150 µg mL−1 and 250 µg mL−1 BDMDAC exhibited excellent antimicrobial efficacy against 5 bacterial pathogens (including 3 endodontic bacteria-Enterococcus faecalis, Porphyromonas gingivalis, and Streptococcus mutans). Cytocompatibility assays using primary human dental pulp stem cells (HDPSCs) derived from 3 donors confirmed over 70% of cell viability. Furthermore, freeze-dried scaffolds demonstrated excellent shelf-life stability for at least six months. Overall, these findings highlight the potential of 3D printed BDMDAC-loaded 3D printed gelatin scaffolds as an effective and cytocompatible platform for root canal disinfection in REPs.