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

Document Type: Original Article


1 Associate Professor, Department of Periodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran

2 Student of Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran

3 Assistant Professor, Department of Human Genetics, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran

4 School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran

5 Department of Biostatistics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, 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.


  1. Asad MT. Fundamentals of genetics. Mashhad, Iran: Jahad Daneshgahi Publications; 2014. [In Persian].
  2. Griffiths AJF, Wessler SR, Lewontin RC, Carroll SB. Introduction to genetic analysis. 9th ed. New York, NY: W.H. Freeman; 2008.
  3. Nussbaum RL, McInnes RR, Willard HF, Hamosh A. Thompson and Thompson genetics in medicine. Philadelphia, PA: Saunders; 2007.
  4. Yazdi-Samadi B, Sayed-Tabatabaei BE. Principles of genetics classical and molecular. Tehran, Iran: University of Tehran; 2015. [In Persian].
  5. Silva N, Abusleme L, Bravo D, Dutzan N, Garcia-Sesnich J, Vernal R, et al. Host response mechanisms in periodontal diseases. J Appl Oral Sci 2015; 23(3): 329-55.
  6. Tonetti MS, Jepsen S, Jin L, Otomo-Corgel J. Impact of the global burden of periodontal diseases on health, nutrition and wellbeing of mankind: A call for global action. J Clin Periodontol 2017; 44(5): 456-62.
  7. Kinane DF, Stathopoulou PG, Papapanou PN. Periodontal diseases. Nat Rev Dis Primers 2017; 3: 17038.
  8. Schenkein HA, Van Dyke TE. Early-onset periodontitis: systemic aspects of etiology and pathogenesis. Periodontol 2000 1994; 6: 7-25.
  9. Watanabe K. Prepubertal periodontitis: A review of diagnostic criteria, pathogenesis, and differential diagnosis. J Periodontal Res 1990; 25(1): 31-48.
  10. Shapira L, Schlesinger M, Bimstein E. Possible autosomal-dominant inheritance of prepubertal periodontitis in an extended kindred. J Clin Periodontol 1997; 24(6): 388-93.
  11. Newman MG, Takei HH, Klokkevold PR, Carranza FA. Carranza's clinical periodontology. Philadelphia, PA: Saunders; 2014.
  12. Michalowicz BS, Aeppli D, Virag JG, Klump DG, Hinrichs JE, Segal NL, et al. Periodontal findings in adult twins.
    J Periodontol 1991; 62(5): 293-9.
  13. Michalowicz BS, Diehl SR, Gunsolley JC, Sparks BS, Brooks CN, Koertge TE, et al. Evidence of a substantial genetic basis for risk of adult periodontitis. J Periodontol 2000; 71(11): 1699-707.
  14. Moore WE, Burmeister JA, Brooks CN, Ranney RR, Hinkelmann KH, Schieken RM, et al. Investigation of the influences of puberty, genetics, and environment on the composition of subgingival periodontal floras. Infect Immun 1993; 61(7): 2891-8.
  15. Gorlin RJ, Stallard RE, Shapiro BL. Genetics and periodontal disease. J Periodontol 1967; 38(1): 5-10.
  16. Lang NP, Bartold PM. Periodontal health. J Periodontol 2018; 89(Suppl 1): S9-S16.
  17. Goh EXJ, Ong MMA. Anatomical, microbiological, and genetic considerations in treatment of Chinese periodontal patients. J Investig Clin Dent 2019; 10(1): e12381.
  18. Goncalves PF, Harris TH, Elmariah T, Aukhil I, Wallace MR, Shaddox LM. Genetic polymorphisms and periodontal disease in populations of African descent: A review. J Periodontal Res 2018; 53(2): 164-73.
  19. Kanazawa S, Segal NL. Do monozygotic twins have higher genetic quality than dizygotic twins and singletons? Hints from attractiveness ratings and self-reported health. Evolutionary Biology 2019; 46(2): 164-9.
  20. Kurushima Y, Bowyer R, Ide M, Hughes FJ, Steves CJ. Genetic and environmental contributions to the association between mood disorder and periodontal disease: A cross-sectional study among female twins in the UK. J Clin Periodontol 2019; 46(1): 40-50.