J Korean Acad Oral Health.  2016 Mar;40(1):9-16. 10.11149/jkaoh.2016.40.1.9.

Differences between middle-aged and older people in association between income level and remaining teeth

  • 1Suji Ida Dental CLinic, Suwon, Korea.
  • 2Department of Dentistry, School of Medicine, Ajou University, Suwon, Korea.
  • 3Department of Preventive Medicine & Public Health, School of Medicine, Ajou University, Suwon, Korea. ajoujkh@ajou.ac.kr


To understand the relationship between monthly household income and number of remaining teeth as an indicator of oral health, and to find the differences between middle-aged and older people in this respect.
This study was conducted on data extracted from the Korean National Health & Nutrition Examination Survey, which surveyed all Korean citizens in 2012. From these data, data of 4502 people about 40 years of age who completed the questionnaires and examination survey were selected and analyzed. This study investigated the main factors affecting the remaining teeth, and analyzed the moderating effect of age on the relationship between income level and remaining teeth.
The average number of remaining teeth was 25.17 for middle-aged people and 15.95 for older people, which was significantly different. The number of remaining teeth for middle-aged people showed a significant relationship with income level, education level, and smoking habit. The number of remaining teeth in older people was related to the same factors, along with an additional factor of whether or not they underwent oral examinations. From the interaction analysis conducted to find the moderating effect of age on the relationship between the number of remaining teeth and income level, the number of remaining teeth was more affected by income level in older people than in middle-aged people.
Income level was strongly related to oral health, particularly in older people. Therefore, it can be concluded that an oral health promotion policy is necessary for low-income people, particularly those in the older age group.


Income level; Interaction; Moderating effect; Oral health inequalities; Remaining teeth

MeSH Terms

Diagnosis, Oral
Family Characteristics
Oral Health


  • Fig. 1. The interaction of age and income level for the number of remaining teeth.

Cited by  1 articles

The relationship between metabolic syndrome components and the number of remaining teeth in Korean adults
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J Korean Acad Oral Health. 2020;44(3):130-137.    doi: 10.11149/jkaoh.2020.44.3.130.



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