Characterization of the biological effect of BiodentineTM on primary dental pulp stem cells

Biodentine™ is relatively a new tricalcium silicate cement that has gained great attention of the researchers due to its biological potential in comparison with other materials. The aim of this study was to investigate the optimum concentrations of Biodentine in relation to its stimulatory or inhibitory effect on proliferation, migration and adhesion of stem cells of human exfoliated deciduous teeth (SHED). The cell cultures of SHED were treated with Biodentine™ extract at four different concentrations; 20mg/ml, 2mg/ml, 0.2mg/ml and 0.02mg/ml. Cells cultured without Biodentine™ were kept as a blank control. The proliferation potential of SHED cells was evaluated by MTT viability analysis for 6 days. Migration potential was investigated by wound healing and transwell migration assays. The growth, survival and communication potential of these cells was determined by Adhesion assay. Results: A significant increase was observed in the proliferation and migration of SHED at (2mg/ml, 0.2mg/ml and 0.02mg/ml) while higher concentration of Biodentine™ (20mg/ml) exhibited cytotoxic effect on the cells. However, three tested Biodentine™ concentrations were similar in effect (non-significant) to adhesion ability of cells when compared with blank control. Conclusion: Our findings suggest that lower concentrations of Biodentine™ can be considered as the optimum concentrations to enhance the stimulatory effect of Biodentine on SHED.

Quality of cellular attachment to various root-end filling materials

OBJECTIVES: This study investigated cellular attachment to 6 root-end filling materials as a measure of the biocompatibility of the materials. MATERIAL AND METHODS: Class I retrograde cavities were prepared in root slices and these cavities were filled with the test materials, and incubated with Balb/C 3T3 fibroblasts for 24 h. Root slices with the cavities left empty served as the controls. The root slices were then processed for scanning electron microscopy, and were viewed to assess the quality of cellular attachment by observing the shape of cells, spread, and membrane outline. RESULTS: The best cellular attachment was observed at MTA and Geristore surfaces: cells exhibited characteristic elongated fibroblastic morphology, with projections of lamellipodia, filopodia, blebs, and microvilli from their surfaces, reflecting good attachment to the material. Fibroblasts attached poorly to the surfaces of IRM, Super EBA, KetacFil and Retroplast. Furthermore, the cells did not attach well to the tooth structure next to IRM and Super EBA. CONCLUSIONS: The present study demonstrated a variation in cellular attachment to different root-end filling materials with the best cellular attachment to the surfaces of MTA and Geristore. IRM and Super EBA, Ketac Fil and Retroplast rendered poor attachment.

Standards of teeth preparations for anterior resin bonded all-ceramic crowns in private dental practice in Jordan

OBJECTIVES: To investigate if general dental practitioners (GDPs) in private practice in Jordan follow universal guidelines for preparation of anterior teeth for resin bonded all-ceramic crowns (RBCs). MATERIAL AND METHODS: A sample (n=100) of laboratory models containing 208 tooth preparations for IPS Empress and In Ceram, featuring work from different GDPs, was obtained from 8 commercial dental laboratories. Aspects of preparations were quantified and compared with accepted criteria defined following a review of the literature and recommendations of the manufactures' guidelines. RESULTS: Subgingival margins on the buccal aspect were noticed in 36 percent of the preparations, 54 percent demonstrated overpreparation with a tendency to overprepare the teeth on the mesiodistal plane more than buccolingual plane. Twenty percent of samples presented a shoulder finish line while a chamfer margin design was noticed in 39 percent. Twenty-nine percent and 12 percent of samples had either a feathered or no clear margin design respectively. Incisal underpreparation was observed in 18 percent of dies of each type. Only 17 percent of all preparations were found to follow the recommended anatomical labial preparations while 29 percent of the RBC preparations were found to have the recommended axial convergence angle. In total, 43 percent of preparations were found to have the recommended depth of the finish line. CONCLUSIONS: It was found that relevant guidelines for RBC preparations were not being fully adhered to in private practice in Jordan.

Toxicity Testing of Restorative Dental Materials Using Brine Shrimp Larvae (Artemia salina)

This study investigated the effect of extracts of different composites, glass ionomer cement (GIC)s and compomers on the viability of brine shrimp larvae. Ethanolic extracts of four dental composites (Z-100; Solitaire 2; Filtek P60 and Synergy), a conventional GIC (Ketac-Fil), a resin-modified glass ionomer cement (Vitremer), two compomers (F2000; Dyract AP), and a flowable compomer (Dyract Flow) were prepared from each material. Following evaporation of the ethanol, the extracts were resuspended in distilled water, which was then used to test the effects on the viability of brine shrimp larvae. For the composites, the extract of Synergy was the least toxic (88 percent viability) followed by the extracts of Solitaire 2, Z100 and P60 (75 percent, 67.5 percent and 50 percent viability, respectively). One-way ANOVA revealed highly significant differences between the resin composite materials (p<0.001). Follow-up comparison between the composite groups by Tukey's pairwise multiple-comparison test (á =0.05) showed that the extract of Synergy was significantly less toxic than the extracts of all the other materials except that of Solitaire 2. The compomers showed 100 percent lethality, while the percentage of viable larvae for the extracts of Ketac-Fil, and Vitremer were 32.3 percent, and 37.0 percent, respectively. One-way ANOVA revealed highly significant differences between the groups of materials (p<0.001). Follow-up comparison between the groups by Tukey's test (á = 0.05) showed that the toxic effect of the extracts of the compomers were significantly greater than that of Ketac-Fil, and Vitremer. The differences in the toxic effects of Vitremer and Ketac-Fil were not statistically significant. In conclusion, the toxicity of composite materials varied according to their chemical composition. Compomers were the most lethal materials to brine shrimp larvae followed by GICs and then composites.