Comparative Evaluation of Cytotoxicity of Root Canal Sealers on Cultured Human Periodontal Fibroblasts: In vitro Study.

AIM: To evaluate and compare the cytotoxic effects of different types of root canal. MATERIALS AND METHODS: The sealers were eluted with culture medium for 1 hour, 7 days, and 14 days. Cell viability was estimated by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and trypan blue exclusion method on human periodontal ligament (PDL) fibroblast cells. Sealers used are mineral trioxide aggregate (MTA)-based sealer (MTA Fillapex, Angelus), calcium hydroxide-based sealer (Apexit Plus, Ivoclar Vivadent), resin-based sealer (AH Plus, Dentsply), and zinc oxide eugenol-based sealer (Tubli Seal, SybronEndo). RESULTS: The order of cytotoxicity through MTT assay, at the end of the second week, was observed as MTA Fillapex> Tubli Seal> Apexit Plus > AH Plus. The percentage cell viability obtained after trypan blue exclusion method decreased in the order of Apexit Plus> Tubli Seal> AH Plus> MTA Fillapex, which was similar to the reported cytotoxicity from the MTT assay after 1 hour. CONCLUSION: Each type of sealer showed moderate-to-severe cytotoxic response when compared with the control. The MTA Fillapex was found to be the most cytotoxic sealer. Use of resin-based material as a root canal sealer may result in a more favorable response to PDL fibroblasts. CLINICAL SIGNIFICANCE: Having knowledge of the cytotoxicity of various sealers will help in increasing patient's comfort.

Evaluating the ability of cultivated odontoblasts to form dentin-like tissue in vitro using fibroblast growth factor and insulin-like growth factor.

Aim: The aim of the study was to evaluate the ability of cultivated odontoblast to form dentin-like tissue using fibroblast growth factor (FGF) and insulin-like growth factor (IGF). Materials and Methods: Dental pulp stem cells (DPSCs) were extracted from 10 human teeth. They were isolated and cultivated in vitro with the use of stem cell markers. The human DPSCs were characterized for trilineage differentiation. They were then differentiated into odontoblasts. The ability of cultivated odontoblasts to form dentin-like tissue was evaluated using FGF and IGF. Results: IGF showed superior ability to form dentin-like tissue as compared to FGF. The addition of FGF showed no significant difference in the formation of dentin-like tissue. A combination of FGF and IGF in odontoblast showed an enhanced ability to form dentin-like tissue. Conclusion: The use of growth factors IGF and FGF with dental stem cells showed a greater potential to form dentin-like tissue. This can profoundly alter the paradigms of conservative vital pulp therapy, which may eventually make it possible to treat dental diseases by regeneration of lost dentine.

Comparative evaluation of coronal discoloration induced by two triple antibiotic revascularization protocols when used at varying depths of temporary sealing material at the end of varying time periods.

AIM: The aim of this study is to evaluate and compare the coronal discoloration induced by two Triple antibiotic paste (TAP 1 and 2), when used with varying depths of 2 and 4 mm of temporary sealing materials at the end of 0, 3, and 6 weeks. OBJECTIVES: (1) To evaluate coronal discoloration induced by TAP-1 when the depth of the temporary restorative material is 2 mm below cementoenamel junction at the end of 0, 3, and 6 weeks. MATERIALS AND METHODS: Forty extracted permanent maxillary central and lateral incisors or single-rooted tooth were collected and chosen for the study. They were then divided into two groups and each group was then subdivided into two subgroups. RESULTS: Both the triple antibiotic paste showed discoloration but it reduced with increase in thickness of temporary cement. CONCLUSION: TAP 1 and TAP 2 both showed an increase in discoloration, greater discoloration was seen with TAP, containing minocycline. There was a steady change in the discoloration from 0 to 6th week. In both the groups, TAP 1 and TAP 2, there was a reduction in discoloration with increase thickness of the temporary restorative material.

Comparative evaluation of the bond strength of posterior composite with different cavity configurations and different liners using a two-step etch and rinse adhesive system: In vitro study.

INTRODUCTION: Conventional Class II cavity preparations used for restoring small lesions with amalgam may be inappropriate for composite resin restorations due to the extensive cavity form, large occlusal contact area, and thin or missing margins of the tooth. Cavity preparation in the proximal areas as per the precepts of Clark is a conservative method of caries excavation and tooth preparation. MATERIALS AND METHODS: Conventional Class II and Clark's Class II cavities were prepared on the mesial surfaces of 60 molars. All cavities were given a standard buccolingual width of 2 mm, an occlusogingival height of approximately 3.5 mm and an axial depth of 1.5 mm. These were then restored using flowable composites or resin-modified glass-ionomer cement liners and nanohybrid composites. The compressive bond strength was tested with a universal testing machine. RESULTS: The compressive bond strength was the highest for Clarks Class II cavity preparation with a lining of flowable composites. Conventional Box only Class II cavities restored with flowable liners showed the next best result. CONCLUSION: Clark's class II cavity preparation can be used as efficiently as the conventional Class II box preparation with the advantage of preserving more tooth structure, more precise tooth preparation, good bond strength and better esthetics.

The evaluation of interfaces between MTA and two types of GIC (conventional and resin modified) under an SEM: An in vitro study.

CONTEXT: Mineral trioxide aggregate (MTA) is a biocompatible repair material that is often used along with glass ionomer cement (GIC) in many clinical situations. AIMS: In this study, the interface of GIC and MTA was examined, and the effect of time on this interface was tested. MATERIALS AND METHODS: Forty 9-mm hollow cylindrical glass molds were filled with MTA and then according to the group either conventional GIC or resin-modified GIC (RMGIC) is filled immediately or after 45 min. The specimens were then sectioned, carbon coated, and examined using a scanning electron microscope (SEM) and the elemental analysis was done. STATISTICAL ANALYSIS: Observational study, no statistical analysis done. RESULTS: The SEM showed that both the groups underwent adhesive separation and gap formation at the interface. The specimens in which GIC was condensed over freshly mixed MTA (group IIA and group IIB) also showed cohesive separation in MTA; however, it was more in the GIC condensed after 45 min over MTA groups (group IA and group IB). The results were better for conventional GIC than RMGIC. CONCLUSIONS: GIC can be applied over freshly mixed MTA with minimal effects on the MTA, but this effect decreases with time.