Jul 13, 2009 - Results: Mercury exposure was independently associated with peri- odontitis (odds ... i Department of Environmental and Occupational Medicine, School of Public Health, Seoul National. University. ...... reports/volume4.pdf.
Volume 80 • Number 12
Mercury Exposure and Periodontitis Among a Korean Population: The Shiwha-Banwol Environmental Health Study Dong-Hun Han,* Sin-Ye Lim,† Bo-Cheng Sun,‡ Sok-Ja Janket,§ Jin-Bom Kim,* Dai-Il Paik,i Domyung Paek,† and Hyun-Duck Kim‡¶
Background: The oral effect of chronic low-level mercury exposure is not completely understood. This study examined whether mercury exposure is associated with periodontitis. Methods: This study cross-sectionally surveyed 1,328 residents (598 males and 730 females) from the prospective Shiwha and Banwol cohort in Korea from July 2005 to August 2006 at baseline. Two dentists assessed periodontitis, an outcome, using the Community Periodontal Index (CPI): CPI 3 or 4 and CPI 0 to 2 were classified as periodontitis and non-periodontitis, respectively. The hair mercury level, the predictor, was analyzed. The mercury level was categorized according to the reference dose of the Environmental Protection Agency of the United States: normal = 15 years of age agreed to enter the survey, and the response rate was 68.2%. The participants were included in this study of their own accord. Of them, 1,343 participants completed the health assessment and questionnaires in Shiwha and Banwol from July 2005 to August 2006. To assess periodontal health status, the inclusion criterion was that subjects had ‡16 teeth. The number of subjects finally included was 1,328 (598 males and 730 females). The ages of subjects ranged from 15 to 84 years, with a mean – SD of 40.8 – 14.1 years. The oral health and the health of other target organs were assessed by many health professionals (DMP,
Han, Lim, Sun, et al.
SYL, DHH, and BCS) participating in the project. Information regarding socio-demographic-economic status and oral/systemic health-related behaviors was obtained from questionnaires. Systemic and dental health status was assessed by clinical examination, and exposure to mercury was assessed by laboratory procedures using hair samples. Assessment of Periodontitis Comprehensive oral examinations were carried out in a dental unit or a mobile dental chair under light. Two trained and calibrated dentists (DHH and BCS) performed the oral examinations to determine the periodontal status using the Community Periodontal Index (CPI), which was developed and recommended by the World Health Organization (WHO) and World Dental Federation (FDI).15 The CPI was selected as a tool for evaluating periodontal health status because it is widely used in the survey of large populations. Five CPI scores were used to evaluate periodontal health status: CPI 0 = normal; CPI 1 = gingival bleeding; CPI 2 = calculus; CPI 3 = shallow periodontal pocket of 4 to 5 mm; and CPI 4 = deep periodontal pocket ‡6 mm. The measurements were made using a CPI probe at six sites (mesio-buccal, mid-buccal, disto-buccal, disto-lingual, mid-lingual, and mesio-lingual) per tooth. Ten teeth were selected for the periodontal examination: two molars in each posterior sextant and the upper right and lower left central incisors. If no index teeth or tooth was present in a sextant qualifying for examination, the adjacent remaining teeth in that sextant were examined. The highest score was recorded as the CPI score for each individual. Prior to the main survey, the two dentists (DHH and BCS) performed a calibration training procedure for CPI measurement: The first procedure consisted of dictation and discussion using slides to obtain validity. The next procedure was the test-retest examination using 43 subjects to verify reproducibility. During the main survey, a total of 100 subjects were selected to check the inter/intraexaminer reliability and validity. One procedure of inter- or intraexaminer reliability used 10 subjects to do the repeated measurements. The procedures to evaluate the test-retest reliability were done 10 times: five times for intraexaminer reliability and five times for interexaminer reliability. The intraexaminer reliability of the two dentists was a k index of 0.84 and 0.97 for two categories (non-periodontitis of CPI 0 to 2 versus periodontitis of CPI 3 or 4). The interexaminer reliability between them was a k index of 0.62. Assessment of Mercury For an evaluation of the body burden of mercury, hair is used as a biomarker of relative chronic exposure.16 Mercury in non-occupationally exposed individuals is incorporated into the hair at the time the hair is formed; the mercury concentration in newly formed 1929
Mercury Exposure Is Associated With Periodontitis
Volume 80 • Number 12
Table 1.
Sociodemographic Variables and Risk Factors of Subjects by Periodontal Status Non-Periodontitis (n = 950)
Periodontitis (n = 378)
P Value*
38.29 – 14.30
47.02 – 11.18
70 USD,
