Bone Loss In Mandible Research Articles

Impact of a CD36 inhibitor on Porphyromonas gingivalis mediated atherosclerosis

ObjectiveTo determine if AP5055 drug, an inhibitor of CD36, prevents the increase in Porphyromonas gingivalis (P. gingivalis) mediated atherosclerosis in low-density lipoprotein receptor knockout (LDLR KO) mice by targeting CD36. MethodsMale LDLR KO mice were infected with P. gingivalis by oral lavage to induce periodontal disease and fed a western diet to induce atherosclerosis. Mice were treated with the CD36 inhibitor, AP5055 (1 mg/kg), or vehicle (1% DMSO). Aortae were dissected and stained with oil red-O for morphometric analysis; blood/plasma was collected to determine markers of inflammation by cytokine array and cholesterol levels. P. gingivalis-induced bone loss in mandibles was assessed using micro-CT. P. gingivalis lipopolysaccharide stimulated nuclear factor-kappa B (NF-κB) activity was measured using a reporter gene (secreted alkaline phosphatase) assay in AP5055 treated or untreated RAW-Blue macrophages. ResultsIsolated aortae showed a significant decrease in lesion area in the AP5055 treated group as compared to the control group. Mechanistically, in vitro analysis demonstrated that AP5055 inhibited NF-κB activity. Cytokine array showed a decrease in the expression of pro-inflammatory cytokines and decreased levels of plasma cholesterol in AP5055 treated mice. Micro-CT measurements of bone loss were not significant between the two groups. ConclusionCD36 inhibitor AP5055 abrogates atherosclerotic lesion burden associated with periodontal disease, accompanied by a reduction in markers of inflammation. These experiments may support the development of drugs targeting CD36 for human disease.

Three‐Dimensional Measurement of Bone Loss at Implants in Patients With Periodontal Disease

The aim of this prospective study is to evaluate the three-dimensional marginal bone level around implants 5 to 15 years after loading in partially edentulous patients treated for generalized chronic periodontitis (GCP) and generalized aggressive periodontitis (GAgP). Seventeen patients with GCP and 17 patients with GAgP were treated with a total of 119 implants. Patients were examined clinically on a 3-month recall schedule after insertion of the superstructure, and radiographs were taken at fixed intervals. At the end of the observation period, cone-beam computed tomography was used for the analysis of the circumferential three-dimensional bone level (mesial, distal, buccal, and lingual/palatal) and determination of keratinized mucosa thickness (KMT). In both groups, a significant bone loss at implants was observed buccally (GAgP group: 4.49 ± 2.93 mm; GCP group: 3.57 ± 2.94 mm) with significantly more average bone loss in patients with GAgP (3.00 ± 1.67 mm) compared to in patients with GCP (2.45 ± 1.08 mm). The lowest values for KMT in both groups were found in the anterior mandible (GAgP group: 0.99 ± 1.13 mm; GCP group: 0.82 ± 0.91 mm). There were significant correlations between clinical parameters and bone loss in mandibles of patients with GAgP. The lowest value for KMT in both groups was found in the mandible. Bone loss was observed buccally and was more pronounced in patients with GAgP, with a significant correlation with keratinized mucosa and increased inflammation.

Analysis of mandibular bone mineral density of senile osteoporosis patients

To investigate the mandibular bone mineral density (BMD) change of senile osteoporosis patients and the relationship between the mandible bone loss and systemic bone loss. Forty senile osteoporotic patients (group A), 40 non-osteoporosis control elders (group B) and 40 healthy youths (group C) were included in this study. Standard digital panoramic tomography (SDPTG) was taken for each participant. Cortical width (CW), panoramic mandibular index (PMI), alveolar bone density and alveolar bone height were measured on the SDPTG. Lumbar and hip BMD were measured with dual energy X-ray absorptiometry (DXA). Close relationship was found between CW (3.57 +/- 0.82) and systemic BMD for osteoporosis patients (P < 0.05). All the SDPTG indices including CW, PMI, alveolar bone density and alveolar bone height were different for osteoporosis patients from the healthy youths (P < 0.05). The osteoporosis patients had thinner CW (3.57 +/- 0.82) and smaller PMI (0.29 +/- 0.06) than non-osteoporosis control elders (CW: 4.07 +/- 0.75, PMI: 0.32 +/- 0.07, P < 0.05). The alveolar bone density (105.40 +/- 20.48) and alveolar bone height (10.42 +/- 1.82) of the non-osteoporosis control elders reduced compared with the healthy youths (alveolar bone density: 117.10 +/- 22.23, alveolar bone height: 11.69 +/- 1.63, P < 0.05). The senile osteoporotic patients had significant mandibular cortical bone loss.

Mandible bone loss in osteoporosis rats.

Change in the mandible during the development of osteoporosis has not been studied extensively. Thus, the present study was undertaken to clarify the target loci in the mandible during the development of experimental osteoporosis in aged female rats. Experimental osteoporosis was studied in 76 Wistar strain female rats, 35 weeks old, by means of ovariectomy and dietary calcium deficiency. The rats were divided into the following three groups: (1) group 1, unoperated basal control (Basal), maintained on a diet containing 1.0% calcium; (2) group 2, sham-operated (Sham), maintained on a diet containing 0.01% calcium; and (3) group 3, ovariecomized (OVX), maintained on a diet containing 0.01% calcium. Fifteen rats of each group, except the basal rats (10 and 6 rats), were killed at 3 and 6 months following ovariectomy, respectively. The mandible was extracted, cleaned, and then subjected to bone mineral content (BMC) and bone mineral density (BMD) analyses using a peripheral quantitative computed tomography (pQCT) bone scanner. Each mandible was scanned from the mesial margin of the first molar to distal margin of the second molar. The results showed that dietary calcium deficiency and ovariectomy caused significant decreases of trabecular and cortical BMCs and BMDs in Sham and OVX rats compared with Basal rats. Decreases due to dietary calcium deficiency were greater than those caused by ovariectomy. However, significant age-related changes were not observed in BMC and BMD in Sham and OVX rats for 3-6 months. In addition, the cortical and trabecular BMCs and BMDs obtained were found to relate to location in the mandible for each group.

A Radiological and Histopathological Study on Dietary Therapy of Bone Loss in Mandible of Adult Rats : On Bone Matrix Formation : 主論文の要旨

A Radiological and Histopathological Study on Dietary Therapy of Bone Loss in Mandible of Adult Rats : On Bone Matrix Formation : 主論文の要旨

Pattern of age related bone loss in mandibles.

A study was carried out to analyze the pattern of the age related bone loss in the mandibular cortex and to establish normal values and the observed range of morphometric variables on microradiograms of bone sections taken from a well defined site anterior to and below the mental foramen. Specimens were obtained from 100 Danish subjects with no known systemic bone disease or severe mandibular atrophy. Microradiograms of 100-micron-thin undemineralized vertical ground cross-sections were produced. An electric point-counting system was used for the determination of 1) percentage bone mass, 2) mean cortical width (MCW), and 3) the percentage of Haversian canals with resorption surfaces. The analysis showed that cortical porosity and the percentage of Haversian canals showing resorption are unrelated to sex and increased after the age of 50. MCW and absolute bone mass (MCW x % bone mass) are greater in males than in females and show a parallel age related decrease after the age of 50. Furthermore, the age related increase in cortical thinning and porosity is dependent on the individual as well as on age. Marked individual variation confined the use of these parameters to group analysis.