MATERIALS AND METHODS: Fifty-three patients with supernumerary tooth were identified retrospectively from 1,275 radiographic reviews who attended the Hospital Universiti Sains Malaysia (USM) Dental Clinic. Informed consent was obtained from the patients prior to the study. Blood samples were collected from 41 patients and DNA extractions were performed out of which 10 samples were chosen randomly for PCR amplification using designated primers for RUNX2 followed by DNA sequencing analysis.
RESULTS: This study involved 28 male patients (68.3%) and 13 female patients (31.7%) with a gender ratio of 2.2:1 and mean age of 15.9 ± 6.2 years. DNA extraction yielded ~ 40 ng/μl of concentrated DNA, and each DNA sample had more than 1500 bp of DNA length. The purity ranged between 1.8 and 2.0. DNA sequencing analysis did not reveal any mutations in exons 5 and 6 of RUNX2.
CONCLUSION: This study did not reveal any mutations in exons 5 and 6 of RUNX2 in non-syndromic patients with supernumerary tooth.
CLINICAL RELEVANCE: Analysis of mutations in RUNX2 is important to enhance the understanding of tooth development in humans.
METHODS: Cell viability was tested on human periodontal ligament fibroblasts (HPLFs) using 3.125 mg/ml, 6.25, 12.5, 25, 50, 100 and 200 mg/ml, on both types of GICs employing MTT assay. For the Comet assay, HPLFs were treated with IC50, IC25 and IC10 of test materials and the tail moments were measured. In the Ames test, four genotypic variants of strains of Salmonella typhimurium (TA100, TA98, TA1537 and TA1535) and a strain of Escherichia coli (WP2 uvrA) were employed. The material tested was extracted using sterile distilled water (0.2 g per ml) at 37 °C for 72 h. This was considered as 100 %, which was diluted to 50, 25, 12.5 and 6.25 % utilizing sterile distilled water. These five concentrations were incubated with the bacterial strains with and without metabolic activation (S9), along with appropriate positive controls. The number of revertant colonies was used to evaluate the outcome.
RESULTS: The highest cell viability (159.4 %) for nano-HA-SiO2-GIC was noticed at 3.125 mg/ml, while the lowest (24.26 %) was observed at 200 mg per ml. IC50, IC25 and IC10 values were 95.27, 51.4 and 20.1 mg/ml for cGIC, 106.9, 55.8 and 22.9 mg/ml for nano-HA-SiO2-GIC, respectively. The IC10 of both test materials showed no significant DNA damage compared to that of the negative control based on the Comet assay. The plate treated with nano-HA-SiO2-GIC showed less than double the average number of revertant colonies compared to that of negative control with regard to the Ames test.
CONCLUSIONS: It can be concluded that nano-HA-SiO2-GIC is non-mutagenic based on the Ames test and did not cause DNA damage at the lowest concentration of IC10 based on the Comet assay.