In vitro Evaluation of the Cytotoxicity of Different Root Canal Filling Materials

Differentiation of Dental Pulp Stem Cells on Gutta-Percha Scaffolds

Advances in treatment of tooth injury have shown that tooth regeneration from the pulp was a viable alternative of root canal therapy. In this study, we demonstrated that Gutta-percha, nanocomposites primarily used for obturation of the canal, are not cytotoxic and can induce differentiation of dental pulp stem cells (DPSC) in the absence of soluble mediators. Flat scaffolds were obtained by spin coating Si wafers with three Gutta-percha compounds: GuttaCore™, ProTaper™, and Lexicon™. The images of annealed surfaces showed that the nanoparticles were encapsulated, forming surfaces with root mean square (RMS) roughness of 136⁻211 nm. Then, by culturing DPSC on these substrates we found that after some initial difficulty in adhesion, confluent tissues were formed after 21 days. Imaging of the polyisoprene (PI) surfaces showed that biomineral deposition only occurred when dexamethasone was present in the media. Spectra obtained from the minerals was consistent with that of hydroxyapatite (HA). In contrast, HA deposition was observed on all Gutta-percha scaffolds regardless of the presence or absence of dexamethasone, implying that surface roughness may be an enabling factor in the differentiation process. These results indicate that Gutta-percha nanocomposites may be good candidates for pulp regeneration therapy.

A Prospective Randomized Comparative Study of Cold Lateral Condensation Versus Core/Gutta-percha in Teeth with Periapical Lesions

INTRODUCTION

The aim of this study was to compare the outcome of root canal treatment using either Thermafil (TF; Dentsply Maillefer, Ballaigues, Switzerland) or the cold lateral condensation (CLC) obturation technique in teeth with periapical lesions and to investigate the influence on postoperative pain and treatment outcomes.

METHODS

After standardized root canal preparation technique, 112 teeth were obturated with either the TF or the CLC technique during 2 sessions by single operator. Postoperative pain, obturation length, and treatment outcomes were recorded. The teeth were reviewed clinically and radiographically for 2 years.

RESULTS

Although there were no significant differences between the techniques in the incidence of postoperative pain at 24 hours (P > .05), the incidence of pain was significantly higher in the TF group than in the CLC group at 48 hours (P < .05). During the 2-year follow-up period, there was no statistically significant difference in the success rate of the teeth treated with TF (96.4%) in comparison with those treated with CLC (98.2%) (P > .05).

CONCLUSIONS

In this study, the outcome of the root canal treatment of teeth using the TF and CLC techniques revealed that these techniques are useful for root canal obturation.

Carrier-based root canal filling materials: a literature review

A review of the literature on the use of carrier based obturation materials focusing on Thermafil and Resilon based obturator (RealSeal 1) are presented in this article. The review addressed the history, apical leakage, coronal leakage, biocompatibility, sealing ability and clinical success of Thermafil and RealSeal 1. Based on the studies gathered, this review concluded that both treatment techniques (Thermafil and RealSeal 1) did not provide excellent apical sealing ability. More research should be done to try to overcome their main drawback, its sealing ability.

A Comparison between Cytotoxicity Induced by Two Resin Based Sealers (2Seal and AH Plus) in Saos-2 and MG-63 Cell Lines

The aim of this study was to evaluate and compare the cytotoxicity induced by two resin-based sealers, 2Seal and AH Plus, in two osteoblast-like cell lines, MG-63 and Saos-2. Using sterile discs of both sealers in complete media, 24- and 72-h extracts were prepared. The extracts were exchanged with Saos-2 or MG-63 cell culture media at 75% confluence, and after 24 h incubation, cell viability tests were performed for each extract and cell line using MTT and trypan blue dye exclusion assays. Corresponding incubated media were used as negative control groups. For both extracts and sealers, cytotoxicity was observed in both cell lines. For Saos-2, there was no statistical difference in toxicity between the sealers for either extract (p > 0.05). For MG-63, the 2Seal 24-h extract and the AH Plus 72-h extract had greater cytotoxicity than the other extracts (p < 0.05(. Both AH Plus and 2Seal demonstrated significant cytotoxicity in these two cell lines. In contrast to 2Seal, the cytotoxicity of AH Plus in the MG-63 cell line increased with extraction time from 24 to 72 h. The AH Plus and 2Seal 24-h extracts showed different levels of cytotoxicity in the MG-63 cell line, while in the Saos-2 cell line there were no detectable differences. This may reflect higher sensitivity of the MG-63 cell line compared to Saos-2 toward cytotoxicity induced by these two sealers, or different kinetics of toxicant release from the sealers.