Ivan Kovačić

Composite-induced toxicity in human gingival and pulp fibroblast cells

Abstract Objective. The most important requirement for a material to be used in medical applications is its biocompatibility. Dental composite materials come into direct contact with oral tissues, especially gingival and pulpal cells. This study was performed to evaluate possible DNA damage in cells of human origin exposed to dental composites in vitro using a cytogenetic assay. Materials and methods. Two composite resins (Vertise Flow, Kalore) were tested on human gingival and pulp fibroblasts using the acridine orange/ethidium bromide viability staining and alkaline comet assay. Cultures were treated with polymerized composites in two different concentrations (20 mg/ml, 40 mg/ml) for 14 days. Chi-square and Kruskall-Wallis non-parametric test were used for the statistical analysis (p < 0.05). Results. Significant cytotoxicity was observed for 40 mg/ml of Vertise Flow in both cultures, while Kalore (40 mg/ml) showed cytotoxic effect only on human pulp fibroblasts. A significant level of DNA damage was detected for both materials and concentrations, in both cell cultures. Conclusion. If the two cell cultures are compared, the pulp cells were more sensitive to the cyto/genotoxic effects of dental composites. Based on the results, one can conclude that the use of tested materials may cause cellular damage in gingival and pulp fibroblasts in vitro.

Residual ridge atrophy in complete denture wearers and relationship with densitometric values of a cervical spine: a hierarchical regression analysis

BACKGROUND The rate of residual ridge atrophy (RRR) and its association with mineral density of other bones have not yet been fully explained. OBJECTIVE To measure RRR over a 5-year period in complete denture wearers and relate it to the density of a cervical spine (CSBD). MATERIALS AND METHODS Sixty-two patients (different gender, age, body mass index, duration of edentulousness (DE) and different denture-wearing habits) participated. A copper stepwedge was attached to the cassette, and 50 lateral radiograms met the criteria to be included. RESULTS A significant decrease in vertical height was observed in all measured sites. The amount of RRR was highest in frontal areas of both jaws and decreased gradually towards lateral regions. Hierarchical regression analysis revealed that the amount of RRR in the maxillary frontal area could be explained up to 48.4% by the variable DE and only up to 6.1% by the CSBD, while gender had almost no influence (1%). Similar results were obtained for the lateral maxillary RRR (33.9%; 7%; 2%), frontal mandibular RRR (40; 8.4; 0.4%) and lateral mandibular RRR (31.5%; 3.4%; 7.7%). CONCLUSION Skeletal bone density, reflecting systemic and hereditary factors, is weakly related to RRR (3.4-8.4%).