“…The causes of tooth loss are mainly caries, periodontal disease, trauma, and fracture 1,2,16) . In addition, tooth loss 4,5,7,10,18,21,22) and a decrease in occlusal support 7,15,20) have also been reported to be risks factors for tooth loss. As tooth loss is irreversible and increases with aging, the number of present teeth is frequently used as a measure in population-based epidemiological studies.…”