Impacts of dental checkups on oral function among Japanese older adults

The current study demonstrated that dental checkup attendance was significantly associated with better oral function in Japanese older adults. These associations remained significant even after adjusting for possible confounders including socioeconomic factors and general and dental healthcare variables. While previous studies have explored the potential impact of dental visits on oral health^15,30, and physical health-related problems^31,32,33, our study specifically addresses the previously unexplored relationship between dental checkups and oral function in the aging population.

Our study revealed that dental checkups were significantly associated with better oral cleanliness, a key determinant in preserving oral function⁴. Regular checkups facilitate early detection of oral health problems and enable personalized oral health education and appropriate hygiene measures, ultimately contributing to improved oral health³⁴. Thus, these findings underscore the importance of dental visits in maintaining oral function over time.

We found that checkup attendees significantly demonstrated better masticatory performance than non-attendees, aligning with previous research³⁴. This association can be explained through several mechanisms: checkups enable early detection of oral diseases like dental caries and periodontal problems, thereby reducing the risk of tooth loss³⁰ and preserving chewing efficiency. Moreover, when tooth loss does occur, timely restorative treatments such as dentures can restore oral function. Our observation that checkup attendees showed better swallowing function aligns with previous findings³⁵. The improvement in swallowing function may be attributed to dental checkups indirectly ensuring proper food breakdown, potentially mitigating dietary restrictions associated with chewing difficulties.

These findings collectively emphasize the importance of preserving natural teeth for optimal masticatory performance and overall well-being in older adults. However, impaired oral function, which may arise from tooth loss, can hinder chewing and processing food and negatively impact nutritional intake, potentially influence BMI in older adults, possibly resulting in underweight or obesity³⁶. It is also important to acknowledge that BMI itself can be a confounding variable, potentially influencing both oral function and nutritional status. Our study confirms a relationship between dental checkup attendance and BMI in older adults, highlighting the importance of an integrated healthcare approach. Dental professionals should be aware of this potential link and collaborate with other healthcare providers to ensure comprehensive care.

While dental checkup attendees showed lower average tongue pressure than non-attendees, this difference may be influenced by age and sex, as tongue pressure varies across age decades and between sexes³⁷. Our study observed a higher proportion of female participants in the checkup group, and conversely, a lower proportion in the non-checkup group. However, the intergroup comparison revealed no significant variation in tongue and lip motor function, suggesting a potential positive impact of oral health education on functional preservation. It is important to note that tongue and lip motor function is influenced by a range of factors beyond age and sex, including other oral functions and psychosocial factors^38,39.

Even though the relationship between remaining teeth and dental checkup attendees shows no significant variation, an average of more than 20 remaining teeth was observed in both groups. This suggested sufficient occlusal support for the mastication⁴⁰. While attendees and non-attendees showed a similar average number of remaining teeth, attendees demonstrated better oral cleanliness. This may be due to dental checkup attendees likely benefit from oral health education and preventive treatments to preserve natural teeth and maintain oral health.

There is no significant association was found between dental checkups and oral dryness in this study. This may be due to the diverse aetiologies of oral dryness, which include systemic diseases and medications that may overshadow any potential impacts of dental checkups. Future research is needed to investigate the complex relationship of these factors in oral health outcomes.

We found that dental checkup attendees had better oral hygiene care, masticatory performance, and swallowing functions. Our findings demonstrated that older adults who do not attend dental checkups experienced a notable decline in oral function. This might be explained by non-adherence to dental checkups, which may overlook the declining oral function until a significant problem arises, necessitating further emergency oral healthcare. Specifically, in our initial analysis, those without dental checkup attendance had a 0.45 unit decrease in oral function compared to those who attended dental checkups. This highlights the fundamental impact of dental care on oral function. This association remains significant across all models, even after adjusting for various factors. Upon adjusting socioeconomic factors including age, sex, education, marital status, and living status, the association remains significant. This consistency suggests that the beneficial effects of dental checkups are directly related to dental care itself, not just a byproduct of socioeconomic status. This aligns with the prior research indicating that routine dental attendees had better overall oral health¹⁵.

Further adjustment for general health status, such as current medications, past medical history, and BMI, does not change the significance of the findings. This indicates that the positive impact of dental checkups on oral function is independent of overall health. Besides, when we consider all potential influencing factors, including oral hygiene practices like toothbrushing frequency and interdental dental brush usage, the association between lack of dental checkups and reduced oral function becomes even more pronounced. This emphasizes the importance of comprehensive dental care, including regular checkups and consistent oral hygiene practices. The consistent significance of these findings across all models highlights the necessity of promoting regular dental checkups among older adults.

The observed decline in oral function among those who do not attend dental checkups calls for public health interventions. These interventions should focus on improving accessibility to dental care, particularly for older adults who may encounter barriers such as financial constraints and physical limitations. This might be explained by non-adherence to dental checkups may overlook the declining oral function until a significant problem arises, necessitating further emergency oral healthcare.

Study limitations

There are several limitations in our study. The cross-sectional nature of the study prevents the establishment of a causal direction. Potential selection bias and convenience sampling constrain the generalizability of the results to the entire population. While we acknowledge that lifestyle behaviors and financial considerations were not accounted for in this study, it is crucial to emphasize that health literacy was also not considered in the present study. Future research should prioritize investigations into the influence of health literacy to enhance our understanding of dental checkup adherence. Longitudinal studies incorporating interventions focused on the impact of lifestyle and financial behaviors are warranted to address the limitations of the present study. Furthermore, it is recommended to explore the psychological and social gradients and disparities in oral function to identify factors affecting older adults’ utilization of preventive oral health measures, including policies and practices.

Measuring oral dryness during a typical checkup usually only involves a quick observation, without usually including in-depth investigations into the causes of reduced salivary flow. Thus, another limitation of this study was that it relies on unstimulated salivary flow (USF) as a measurement. However, since USF measures saliva production at rest, a routine checkup is unlikely to significantly change it, making the results potentially unreliable.

Clinical implications

This study investigates the impact of dental checkup attendance on oral function in older adults, an area of focus given the globally aging populations. The robust association between dental checkup attendance and oral function across all analytical models underscores the reliability of our findings and adds to the existing body of knowledge. Our comprehensive approach, adjusting for socioeconomic status, general health, and oral hygiene practices, provides a better understanding of this relationship.

The increased associations observed in model III highlight the synergistic role of both dental visits and daily oral hygiene practices in maintaining oral function. Our findings suggest integrating comprehensive oral function assessments into routine dental examinations. While most participants maintained adequate tooth count, their oral function declined, particularly in hygiene, mastication, and swallowing. This indicates that dental care should focus on both tooth preservation and functional quality. These results have significant implications for public health initiatives clinically.

Healthcare providers should implement preventive strategies with early detection of functional decline, particularly for vulnerable populations (older adults, low socioeconomic status, poor oral hygiene, compromised dentition). Healthcare policy should address financial and physical barriers to dental care access to ensure equitable preventive care delivery. Encouraging both professional dental care and consistent home hygiene practices is crucial for preserving oral function and overall well-being in later life.

Future research recommendations

Future studies should focus on conducting robust longitudinal research to establish causal relationships between dental checkups and oral function decline in older adults. Researchers should investigate socioeconomic, cultural, and geographical barriers to dental care access through mixed-method approaches, combining quantitative and qualitative research. The development of standardized oral health surveillance systems is essential to monitor and evaluate intervention effectiveness across different populations.

To better understand the relationship between dental checkups and oral dryness, future research should consider multiple methods of measuring oral dryness, the impact of underlying medical conditions, the role of medications, and a more comprehensive study design to account for confounding variables. It is also advisable to explore the impact of dental checkup frequency and oral health literacy on older adults.

Additionally, research should evaluate the impact of various public health policies on dental care accessibility, particularly focusing on insurance coverage protocols for underserved populations. Studies examining the effectiveness of different dental education programs and their influence on regular checkup attendance would provide valuable insights for healthcare policy development. These could strengthen evidence-based preventive dental healthcare frameworks that optimize oral function and enhance the quality of life for older adults.