Fig. 4

Changes in number of teeth and occlusal force with advancing age. a Number of teeth stratified by age (n = 1,022 employees). Mean numbers of employees in each age group were as follows: 20 s (n = 3), 30 s (n = 102), 40 s (n = 382), 50 s (n = 315), 60 s (n = 174), 70 s (n = 47). b Occlusal force stratified by age (n = 764 employees). Mean numbers of employees in each age group were as follows: 20 s (n = 3), 30 s (n = 83), 40 s (n = 270), 50 s (n = 241), 60 s (n = 132), 70 s (n = 35). Data are shown as means ± SE. Kruskal–Wallis test with post hoc Bonferroni test was used for multiple comparisons across the six groups. NS, not significant