Fig. 1.

a Schematic of a tooth and supporting tissues affected by periodontal disease. Bacterial plaque accumulates on tooth surface and initiates a cellular immune response that activates downstream MMP and osteoclast activity that destroy the supporting bone and connective tissue. The cellular response, cytokine expression, and regulation of inflammatory pathways differ in periodontal disease between young (left) and older (right) adults. Images rendered using micro-CT of the three maxillary molar teeth of mice in b health and c with periodontal disease. Red lines indicate differences in bone loss that can be quantified as a measure of disease severity. d Representative histological section of a mouse molar tooth that depicts the supporting bone (B) connective tissue (C), the tooth (T), and the pulp of the tooth (P). Part a is created with Biorender.com