Assessment of age-related changes on oral diadochokinesis and masticatory function in healthy old adults

Abstract

Purpose This cross-sectional study aimed to identify the age-related change of oral diadochokinetic function and its association with various orofacial factors in healthy old adults. There is a lack of consensus diagnostic values of tongue-lip motor function and oral dryness to diagnose oral frailty. Material and Methods A total of 385 healthy participants were divided into three different age groups: 20–64 years(Gr1); 65–74 years(Gr2); and ≥75 years(Gr3). To investigate the tongue-lip motor functional ability, oral diadochokinesis(ODK) was assessed as the number of repetitions of the monosyllable /pa/ta/ka/. Both subjective and objective masticatory functional assessments were conducted for masticatory function evaluation. Four questionnaires were used for subjective masticatory ability, cognitive ability, and psychological status. For the dynamic objective masticatory function, masticatory performance(MP), bite force(BF), and occluding area were examined, and for the static objective masticatory function, the number of remaining teeth and functional tooth pairs. Handgrip strength(HG), oral dryness, and tongue pressure(TP) were assessed to identify influencing factors. Intergroup differences were evaluated by the ANOVA and Kruskal-Wallis test, and the correlations between ODK and orofacial factors were evaluated. Results This study revealed significant age-related declines in TP, HG, and ODK /pa/ta/ka/, especially after 65 years. PHQ-9 scores and oral dryness showed significant differences between Gr1 and Gr3. Factors affecting MP were Posterior teeth, Eichner index, BF, Occluding area, KMMSE, ODK /pa/ta/ka/. MP is affected by /pa/ta/ at age for Gr2 and /pa/ta/ka/ for Gr3. Each syllable of ODK was associated with different factors but common factors associated with ODK /pa/ta/ka/ were MP, HG, and PHQ-9. For the syllable /pa/ta/, Eichner Index, TP, and oral dryness were additionally associated. MP, TP, HG, oral dryness, and KMMSE were associated ODK/ka/ in Gr3. Conclusions The cut-off values of each orofacial factor and each association with MP and ODK were investigated for the diagnosis of oral frailty and oral hypofunction, the findings of which could give a practical intuition for recovery of oral function in old adults. These findings contribute to a comprehension of age-related variations in oral function and the multifactorial nature of masticatory dynamics. 목적 본 연구는 건강한 노인을 대상으로 연령에 따른 구강운동과 저작기능을 평가하는 것을 목적으로 하였다. 방법 2020년 8월 1일부터 2023년 1월 31일까지 연세대학교 치과대학병원 통합치의학과에 내원한 총 385명의 건강한 참가자를 20-64세(그룹 1), 65-74세(그룹 2), ≥75세(그룹 3)의 세 가지 연령대로 나누었다. 구강운동 기능을 조사하기 위해 Oral diadochokinesis(ODK)를 단음절 /pa/ta/ka/의 반복 횟수로 평가하였다. 저작기능 평가를 위해 주관적 및 객관적 저작 기능 평가가 모두 실시되었다. 주관적 저작 능력, 인지 능력, 심리적 상태 평가를 위해 4개의 설문지가 사용되었다. 동적 객관적 저작 기능의 경우 저작 효율, 교합력, 교합 면적을 조사하였고, 정적 객관적 저작 기능의 경우 남아 있는 치아 수와 기능적 치아 쌍을 평가하였다. 영향 요인을 파악하기 위해 악력, 구강 건조도, 설압을 평가하였다. 그룹 간 차이는 ANOVA 및 Kruskal-Wallis 검정으로 평가하였고, ODK와 구강 기능 인자들의 상관관계를 평가하였다. 결론 구강 노쇠와 구강 기능 저하 진단을 위하여 연령대별 구강 기능 인자들의 평가값과 ODK와 저작 효율과의 연관성을 조사하였으며, 이러한 결과는 연령대별 구강 기능의 변화와 저작 기능의 다요인적 특성을 이해하여 노인의 구강 기능 회복을 이해하는데 기여했다.