Did expanded access to denture services improve chewing ability in the Korean older population? Results of a regression discontinuity analysis

The Effects of the Expansion of Dental Care Coverage for the Elderly

BACKGROUND

Expanding dental care coverage for the elderly is globally recommended but not widely implemented due to its high costs and intangible benefits.

METHODS

This study examined the impact of such an expansion in Korea using the imputation-based method proposed by Borusyak et al. We analyzed data from the Korea National Health and Nutrition Examination Survey (2007-2019) on dental service utilization and chewing ability among older adults.

RESULTS

The policy resulted in a 13.5% increase in partial denture use and a 60.5% increase in dental implants among those aged 65 and above. These changes corresponded with reductions in severe chewing difficulty by 23.3% and 13.0%, respectively. No significant changes were observed in full denture use. The price elasticity of demand for partial dentures and dental implants was estimated to be -0.19 and -0.86, respectively.

CONCLUSIONS

These findings underscore the critical role of affordability in enhancing the utilization of dental implants among the elderly and highlight the importance of appropriately expanding dental insurance coverage to improve oral health outcomes in this population.

Dental Services Use: Medicare Beneficiaries Experience Immediate And Long-Term Reductions After Enrollment

Traditional Medicare does not cover routine dental care, but little is known about transitions in dental outcomes upon reaching Medicare eligibility at age sixty-five. Using data from the 2010-19 Medical Expenditure Panel Surveys, we examined dental insurance, utilization, and outcomes among US adults before and after age sixty-five, using a regression discontinuity design and segmented regression analysis. Among 97,108 US adults representing a weighted population of 104,787,300 people, complete edentulism, or the loss of all teeth, increased by 4.8 percentage points at age sixty-five, and the percentage of people receiving restorative dental care decreased by 8.7 percentage points. Enrollment in Medicare Advantage, which may offer a dental benefit, was not associated with greater use of dental services relative to traditional Medicare, and Medicare Advantage enrollees had a significantly larger drop in dental spending from private insurance at age sixty-five than traditional Medicare enrollees. Expanding Medicare to cover dental services may help counteract these effects among all enrollees.

Age period cohort analysis of chewing ability in Korea from 2007 to 2018

There have been marked improvements in oral health in Korea during the past 10 years, including chewing ability. We sought to disentangle age, period, and cohort effects in chewing ability between 2007 and 2018. We analyzed data from the Korea National Health and Nutrition Examination Survey. The main variable was chewing difficulty, which was assessed among participants aged 20 years and older. APC analysis revealed three trends in chewing difficulty: (1) there was an increase in chewing difficulty starting at around 60 years of age (age effect), (2) there was a steady decrease in chewing difficulty during the observation period (period effect), and (3) chewing ability improved with each successive generation born after 1951 (cohort effect). Regarding recent improvements in chewing ability, cohort effects were somewhat more important than period effects.

The deterioration of oral function and orofacial appearance mediated the relationship between tooth loss and depression among community-dwelling older adults: A JAGES cohort study using causal mediation analysis

BACKGROUND

Depression is a major health problem among older adults, for which previous studies have suggested tooth loss as a risk factor. This study examined the mediating effect of oral function and orofacial appearance in the relationship between tooth loss and depression.

METHODS

This three-year follow-up longitudinal study was based on a self-reported questionnaire targeting community-dwelling older adults aged ≥65 years. We used the incidence of depressive symptoms during follow-up as the outcome, the number of remaining teeth (≥20/≤19) as the exposure, and the deterioration of oral function and orofacial appearance (speaking, smiling, and eating) as mediators. We fitted the logistic regression model including confounders and calculated the natural indirect effect (NIE), natural direct effect, and the proportion mediated (PM) by the deterioration of oral functions by applying the causal mediation analysis framework.

RESULTS

The mean age of the 8,875 participants was 72.7 years (1SD=5.5) and 48.0% were male. Depressive symptoms developed during follow-up in 11.5% of the participants (n=1,024). The incidence for those with ≤19 and ≥20 remaining teeth was 13.1% and 9.2%, respectively. Total effect of fewer remaining teeth (≤19) on depressive symptoms was OR=1.30 (95%CI=1.12-1.51). Difficulty in speaking (NIE OR=1.03, 95%CI=1.00-1.06, PM=12.4%), problems in smiling (NIE OR=1.04, 95%CI=1.01-1.07, PM=16.9%), and difficulty in chewing (NIE OR=1.05, 95%CI=1.02-1.09, PM=21.9%) significantly mediated the relationship.

LIMITATION

Selection bias due to dropout.

CONCLUSION

Deterioration of oral function and orofacial appearance were mediating factors of the mechanism for the relationship between tooth loss and the incidence of depressive symptoms.

Did Expanded Dental Insurance Improve Chewing Ability in the Older Korean Population? Results of an Interrupted Time-series Analysis

Background

In 2012, the Korean National Health Insurance extended its coverage to include denture services for older adults. We examined whether the new policy resulted in improved chewing ability in the eligible population.

Methods

We used interrupted time-series (ITS) analysis, a quasi-experimental design, to analyze the effect of the policy. We used data from the Korea National Health and Nutrition Examination Survey conducted from 2007 to 2016–2018. The study population consisted of two groups: the treatment group, aged 65 years or older and eligible for the dental insurance benefit; and the control group, those younger than 65 years and ineligible. The main evaluated outcome was self-reported chewing difficulty.

Results

The ITS analysis showed that chewing difficulty decreased annually by 0.93% (95% CI, −1.30 to −0.55%) and 0.38% (95% CI, −0.59 to −0.16%) after the policy extension in the older than 65 and younger than 65 groups, respectively. However, we could not conclude that the insurance extension affected chewing difficulty because there was a decrease in the control group as well.

Conclusion

Chewing ability improved in both older and younger adults regardless of dental insurance coverage for older adults. Other exogenous factors probably led to the improvements in chewing ability as well as dental insurance benefits.