Design of the tooth extraction procedure and CT measurement.

<p>(a) This CT image details the condition of third molar teeth covered with cortical bone. The regions of interest in CT image analysis were (I) the buccal cortical bone area, which was taken for biopsy during surgery; and (II) the region under the cortical bone, which indicates cancellous bone near the third molar tooth. (b) Removal of the third molar tooth. The envelope flap is raised, revealing the cortical bone. The line indicates the biopsy area. (c) Orthopantomographs showing impacted third molar teeth.</p

Schematic illustration of the formation mechanisms of the chronic focal bone consolidation.

<p>Schematic illustration of the formation mechanisms of the chronic focal osteomyelitis. The chronic bacterial infection around tooth would induce tissue damage and it resulted in osteocytes death and resulted in micropetrosis. These accumulation of micropetrosis might induce bone sclerosis. Red arrow head shows cancellous bone consolidation.</p

Pathological features.

<p>(a) A representative image of viable bone (x100). Normal-appearing bone that is remodeling, with osteoblasts, and osteocytes present. Occasional empty osteocytic lacunae (<10–20% of lacunae per high magnification) may be present in the absence of an inflammatory reaction. (b) High magnification of viable bone (x200). There are osteoblasts at the border of bone marrow. Arrow head shows osteoblasts. (c) Non-viable bone (×100). Empty osteocytic lacunae and absence of osteoblasts. Empty lacunae are representative of osteocytic death. Arrow head shows empty lacunae. (d) High magnification of non-viable bone (×200). Osteoclasts are present; however, the inflammatory reaction is minimal. (e) Osteomyelitis: prominent inflammatory cell infiltration in fibrous marrow, with osteoblastic activity creating irregular bony trabeculae (×200). (f) High magnification of osteomyelitis (×200). Necrotic bone (sequestrum), abundant bacterial colonies are shown.</p

Three age categories of cortical and cancellous bone radiodensity.

<p>(a) Three age categories of cortical bone radiodensity are not significantly differences (ANOVA and Bonferroni correction, <i>P</i> = 0.180; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073897#pone-0073897-g003" target="_blank">Figure 3c</a>). (b) Three age categories of cancellous bone radiodensity are significant differences (ANOVA and Bonferroni correction, *<i>P</i><0.05, **<i>P</i><0.01; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073897#pone-0073897-g003" target="_blank">Figure 3d</a>).</p

Correlation between histological features and age in cortical bone.

<p>(a) There is a statistically significant negative correlation between age and osteocytic density (cells/mm²) (n = 56, r = −0.51, <i>P = </i>0.0001). (b) Density of bone lacunae (lacunae/mm²) does not correlate significantly with age (n = 56, r = −0.257, <i>P = </i>0.0555). (c) Density of empty lacunae (empty lacunae/mm²) does not correlate significantly with age (n = 56, r = 0.059, <i>P = </i>0.6678).</p

Three age categories of histological features of cortical bone.

<p>(a) Three age categories of osteocytic density (cells/mm²). There are statistically significant differences (ANOVA and Bonferroni correction, *<i>P</i><0.05, **<i>P</i><0.01). (b) Three age categories of bone lacunae density (lacunae/mm²). There are no statistically significant differences (ANOVA and Bonferroni correction, <i>P</i> = 0.139). (c) Three age categories of empty bone lacunae density (empty lacunae/mm²). There are no statistically significant differences (ANOVA and Bonferroni correction, <i>P</i> = 0.470).</p

Inter- and intraobserver reliability of the HU measurement.

<p>Inter- and intraobserver reliability of the HU measurement.</p

The distribution of three age categories of pathological features.

<p>The distribution of three age categories of pathological features. Old generation shows 100% focal sclerotic osteomyelitis histopathologically, whereas young generation shows relatively few osteomyelitis.</p

Schemes and representative MDCT images of classification into 3 groups based on the presence or absence of continuity between the GT and the top of masses in alveolar bone.

<p><b>(A)</b> Scheme of Group 1, which was defined as cases in which an almost intact GT (asterisk) continues to the top of the mass (star). <b>(B)</b> An MDCT image of a mass classified as Group 1. (<b>C)</b> Scheme of Group 2, which was defined as cases in which an expanded GT (arrow) continues to the top of the mass (star). (<b>D)</b> An MDCT image of a mass classified as Group 2. (<b>E)</b> Scheme of Group 3, which was defined as cases in which the GT is not continuous with the tumor or cyst (star). <b>(F)</b> An MDCT image of a mass classified as Group 3.</p

Continuity of each type of mass with the gubernaculum tract.

<p>Continuity of each type of mass with the gubernaculum tract.</p