This study evaluated the dentinal penetration depth of 2.5% sodium hypochlorite (NaOCl) in root canals with and without preparation and different irrigant activation protocols.

Sixty-three bovine mandibular incisors were randomly allocated to 6 groups (n = 10): G1, preparation + conventional needle irrigation (CNI); G2, preparation + passive ultrasonic irrigation (PUI); G3, preparation + Odous Clean (OC); G4, no preparation + CNI; G5, no preparation + PUI; G6, no preparation + OC; and CG (negative control; n = 3). Samples were filled with crystal violet for 72 hours. Irrigant activation was performed. Samples were sectioned perpendicularly along the long axis, 3 mm and 7 mm from the apex. Images of the root thirds of each block were captured with a stereomicroscope and analyzed with an image analysis software. One-way analysis of variance, followed by the Tukey post hoc test, and the Student’s t-test were used for data analysis, with a significance level of 5%.

The NaOCl penetration depth was similar when preparation was performed, regardless of the method of irrigation activation (p > 0.05). In the groups without preparation, G6 showed greater NaOCl penetration depth (p < 0.05). The groups without preparation had a greater NaOCl penetration depth than those with preparation (p = 0.0019).

The NaOCl penetration depth was similar in groups with root canal preparation. Without root canal preparation, OC allowed deeper NaOCl penetration. The groups without preparation had greater NaOCl penetration than those undergoing root canal preparation.

This study compared the clinical and radiological outcomes of regenerative endodontic procedures (REPs) using blood clots (BCs), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) through intraoral periapical radiography (IOPAR) and cone-beam computed tomography (CBCT).

Forty-five single-rooted necrotic teeth with periapical pathology were randomly allocated to receive BC, PRP, or PRF as an individual scaffold. Outcomes were evaluated in 35 teeth in 23 patients with a follow-up period of 12–24 months through qualitative IOPAR scoring and quantitative CBCT measurements. Healing of periapical lesions and in immature teeth, changes in the apical foramen diameter (AFD), root wall thickness (RWT), and root length (RL) were assessed. A p value less than 0.05 was considered to indicate statistical significance.

All teeth were asymptomatic except 1 in the PRP group. Periapical lesion healing was seen in all except 2 teeth in the BC group and 3 in the PRP group. Both IOPAR and CBCT revealed no significant differences in bone healing or changes in AFD, RWT, and RL among the 3 groups. A positive pulp sensibility response to the cold test was seen in 2 teeth in the BC group, but none to the electric pulp test. Intracanal calcification (ICC) was evident in more teeth in the BC group than in the PRP and PRF groups, and was also significantly higher in immature teeth.

Our results revealed that BC, PRP, and PRF have similar potential as scaffolds in REPs, and ICC may be a concern for long-term outcomes.

Regenerative endodontic treatment is a clinical procedure aimed at biologically regenerating damaged root canal tissue of immature permanent teeth. This study aimed to report the outcomes of regenerative endodontic treatment performed by endodontic postgraduate students.

Clinical and radiographic data of 27 patients, aged 10–22 years, who underwent regenerative treatment of immature permanent teeth from 2015 to 2019 were followed up, wherein clinical and radiographic examinations were performed for each patient. Postoperative success rate and tooth survival were analyzed, and the postoperative radiographic root area changes were quantified.

A total of 23 patients attended the dental appointments, showing that all teeth survived and were asymptomatic. Specifically, 7 periapical pathosis cases were completely healed, 12 were incompletely healed, and 4 cases failed. Moreover, significant differences were found between discolored and non-discolored teeth, and between the presence or absence of periapical radiolucency. Additionally, 3 anterior teeth showed complete closure of the apical foramen, while the apical foramen width was reduced in 17 teeth and failed in 3 teeth. Root length was also found to have been increased in 7 anterior and 4 posterior teeth, and the average length ranged from 4.00–0.63 mm in the anterior teeth, 2.85–1.48 mm of the mesial root, and 2.73–2.16 mm of the molar teeth distal root. Furthermore, calcified tissue deposition was observed in 7 teeth.

A favorable outcome of regenerative endodontic treatment of immature permanent teeth with necrotic pulp was achieved with a high survival rate.

This study compared the Biodentine, MTA Repair HP, and Bio-C Repair bioceramics in terms of bond strength to dentin, failure mode, and compression.

Fifty-four slices obtained from the cervical third of 18 single-rooted human mandibular premolars were randomly distributed (n = 18). After insertion of the bioceramic materials, the push-out test was performed. The failure mode was analyzed using stereomicroscopy. Another set of cylindrically-shaped bioceramic samples (n = 10) was prepared for compressive strength testing. The normality of data distribution was analyzed using the Shapiro-Wilk test. The Kruskal-Wallis and Friedman tests were used for the push-out test data, while compressive strength was analyzed with analysis of variance and the Tukey test, considering a significance level of 0.05.

Biodentine presented a higher median bond strength value (14.79 MPa) than MTA Repair HP (8.84 MPa) and Bio-C Repair (3.48 MPa), with a significant difference only between Biodentine and Bio-C Repair. In the Biodentine group, the most frequent failure mode was mixed (61%), while in the MTA Repair HP and Bio-C Repair groups, it was adhesive (94% and 72%, respectively). Biodentine showed greater resistance to compression (29.59 ± 8.47 MPa) than MTA Repair HP (18.68 ± 7.40 MPa) and Bio-C Repair (19.96 ± 3.96 MPa) (p < 0.05).

Biodentine showed greater compressive strength than MTA Repair HP and Bio-C Repair, and greater bond strength than Bio-C Repair. The most frequent failure mode of Biodentine was mixed, while that of MTA Repair HP and Bio-C Repair was adhesive.

This study evaluated the effects of low and moderate concentrations of triple antibiotic paste (TAP) and double antibiotic paste (DAP) loaded into a hydrogel system on crown discoloration and explored whether application of an adhesive bonding agent prevented crown discoloration.

Intact human molars (n = 160) were horizontally sectioned 1 mm apical to the cementoenamel junction. The crowns were randomized into 8 experimental groups (calcium hydroxide, Ca[OH]₂; 1, 10, and 1,000 mg/mL TAP and DAP; and no medicament. The pulp chambers in half of the samples were coated with an adhesive bonding agent before receiving the intracanal medicament. Color changes (ΔE) were detected by spectrophotometry after 1 day, 1 week, and 4 weeks, and after 5,000 thermal cycles, with ΔE = 3.7 as a perceptible threshold. The 1-sample t-test was used to determine the significance of color changes relative to 3.7. Analysis of variance was used to evaluate the effects of treatment, adhesive, and time on color change, and the level of significance was p < 0.05.

Ca(OH)₂ and 1 and 10 mg/mL DAP did not cause clinically perceivable tooth discoloration. Adhesive agent use significantly decreased tooth discoloration in the 1,000 mg/mL TAP group up to 4 weeks. However, adhesive use did not significantly improve coronal discoloration after thermocycling when 1,000 mg/mL TAP was used.

Ca(OH)₂ and 1 and 10 mg/mL DAP showed no clinical discoloration. Using an adhesive significantly improved coronal discoloration up to 4 weeks with 1,000 mg/mL TAP.

The aim of this study was to evaluate bacterial nanocellulose (BNC) membranes incorporated with antimicrobial agents regarding cytotoxicity in fibroblasts of the periodontal ligament (PDLF), antimicrobial activity, and inhibition of multispecies biofilm formation.

The tested BNC membranes were BNC + 1% clindamycin (BNC/CLI); BNC + 0.12% chlorhexidine (BNC/CHX); BNC + nitric oxide (BNC/NO); and conventional BNC (BNC; control). After PDLF culture, the BNC membranes were positioned in the wells and maintained for 24 hours. Cell viability was then evaluated using the MTS calorimetric test. Antimicrobial activity against Enterococcus faecalis, Actinomyces naeslundii, and Streptococcus sanguinis (S. sanguinis) was evaluated using the agar diffusion test. To assess the antibiofilm activity, BNC membranes were exposed for 24 hours to the mixed culture. After sonicating the BNC membranes to remove the remaining biofilm and plating the suspension on agar, the number of colony-forming units (CFU)/mL was determined. Data were analyzed by 1-way analysis of variance and the Tukey, Kruskal-Wallis, and Dunn tests (α = 5%).

PDLF metabolic activity after contact with BNC/CHX, BNC/CLI, and BNC/NO was 35%, 61% and 97%, respectively, compared to BNC. BNC/NO showed biocompatibility similar to that of BNC (p = 0.78). BNC/CLI showed the largest inhibition halos, and was superior to the other BNC membranes against S. sanguinis (p < 0.05). The experimental BNC membranes inhibited biofilm formation, with about a 3-fold log CFU reduction compared to BNC (p < 0.05).

BNC/NO showed excellent biocompatibility and inhibited multispecies biofilm formation, similarly to BNC/CLI and BNC/CHX.

The biocompatibility of two experimental scaffolds for potential use in revascularization or pulp regeneration was evaluated.

One resilient lyophilized collagen scaffold (COLL), releasing metronidazole and clindamycin, was compared to an experimental injectable poly(lactic-co-glycolic) acid scaffold (PLGA), releasing clindamycin. Human dental pulp stem cells (hDPSCs) were seeded at densities of 1.0 × 10⁴, 2.5 × 10⁴, and 5.0 × 10⁴. The cells were investigated by light microscopy (cell morphology), MTT assay (cell proliferation) and a cytokine (IL-8) ELISA test (biocompatibility).

Under microscope, the morphology of cells coincubated for 7 days with the scaffolds appeared healthy with COLL. Cells in contact with PLGA showed signs of degeneration and apoptosis. MTT assay showed that at 5.0 × 10⁴ hDPSCs, COLL demonstrated significantly higher cell proliferation rates than cells in media only (control, p < 0.01) or cells co-incubated with PLGA (p < 0.01). In ELISA test, no significant differences were observed between cells with media only and COLL at 1, 3, and 6 days. Cells incubated with PLGA expressed significantly higher IL-8 than the control at all time points (p < 0.01) and compared to COLL after 1 and 3 days (p < 0.01).

The COLL showed superior biocompatibility and thus may be suitable for endodontic regeneration purposes.

Sodium hypochlorite (NaOCl) is an excellent bactericidal agent, but it is detrimental to stem cell survival, whereas intracanal medicaments such as calcium hydroxide (Ca[OH]₂) promote the survival and proliferation of stem cells. This study evaluated the effect of sequential NaOCl and Ca[OH]₂ application on the attachment and differentiation of dental pulp stem cells (DPSCs).

DPSCs were obtained from human third molars. All dentin specimens were treated with 5.25% NaOCl for 30 min. DPSCs were seeded on the dentin specimens and processed with additional 1 mg/mL Ca[OH]₂, 17% ethylenediaminetetraacetic acid (EDTA) treatment, file instrumentation, or a combination of these methods. After 7 day of culture, we examined DPSC morphology using scanning electron microscopy and determined the cell survival rate with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We measured cell adhesion gene expression levels after 4 day of culture and odontogenic differentiation gene expression levels after 4 wk using quantitative real-time polymerase chain reaction.

DPSCs did not attach to the dentin in the NaOCl-treated group. The gene expression levels of fibronectin-1 and secreted phosphoprotein-1 gene in both the Ca[OH]₂- and the EDTA-treated groups were significantly higher than those in the other groups. All Ca[OH]₂-treated groups showed higher expression levels of dentin matrix protein-1 than that of the control. The dentin sialophosphoprotein level was significantly higher in the groups treated with both Ca[OH]₂ and EDTA.

The application of Ca[OH]₂ and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment.