A comparative evaluation of periodontal parameters and oral health in the twins of Khorasan Province, Iran

BACKGROUND AND AIM: Several risk factors contribute to periodontal diseases. Studying twins has helped increase our knowledge on the roles of genetic and environmental factors in periodontal diseases. The objective of this study was the evaluation of periodontal parameters in the twins of Khorasan Province, Iran. METHODS: This study was carried out on 30 pairs of twins between 12-35 years old including 12 pairs of monozygotic (MZ) twins and 18 pairs of dizygotic (DZ) twins with the average age of 18 years old. Periodontal parameters studied consisted of: probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP). Analyses were conducted through SPSS software. T-test was used to examine the differences between MZ and DZ twins also between first twin and second twin. Significance level was set at 0.05. RESULTS: The amounts of PPD (P = 0.045) and CAL (P = 0.003) were significantly different between MZ and DZ twins, while no significant difference in BOP (P = 0.474) was observed between the two groups. Studying heritability showed that BOP could be affected by environmental factors (h2 = 0.41), while CAL and PPD were affected by genetic factors (h2 = -0.70 and h2 = -0.61, respectively). CONCLUSION: Our study confirms previous studies which had focused on the role of genetic factors in periodontal diseases. It indicates that in twins, PPD and CAL are mostly affected by genetic factors, while BOP is mainly affected by environmental factors.