Relationship between vertical mandibular bone atrophy and the number of remaining teeth in elderly Indonesian individuals

Objectives
The severity of jawbone atrophy differs among individuals and even within an individual. This study investigated the relationship between vertical mandibular bone atrophy and the number of remaining teeth in elderly Indonesian individuals.

Material and methods
A total of 148 panoramic radiographs of patients aged ≥ 50 years were selected from dental records at the Radiology Department, Dental Hospital Faculty of Dentistry, Universitas Indonesia, in 2017. To measure vertical mandibular bone atrophy, a vertical line was created running from the crest of the alveolar ridge to the most inferior point of the mandibular inferior cortex through the center of the mental foramen. Subjects were first divided into four groups based on the number of remaining teeth: group I had 1-8 remaining teeth, group II had 9-16, group III had 17-24, and group IV had 25-32.

Results
The number of remaining teeth was significantly associated with vertical mandibular bone atrophy. Mean differences and standard deviations for vertical mandibular bone atrophy were significantly higher in groups III and IV patients than in group I and II patients (group I vs. group III: 5.2 ± 1.7, p = 0.016; group I vs. group IV:  5.8  ± 1.6, p =  0.005; group II vs. group III: 3.2 ± 1.1, p = 0.023; and group II vs. group IV: 3.8 ± 1.1, p = 0.003). Patients with fewer remaining teeth were 1.78 times more at risk for a decrease in their mandibular bone volume than those with more remaining teeth. Males were 1.78 times more likely to have a higher mandibular bone volume than females.

Conclusion
Mandibular bone atrophy was significant in patients with fewer than half of the total number of teeth remaining.