Assessment of linear measurements of bone for implant sites in the presence of metallic artefacts using cone beam computed tomography and multislice computed tomography.

The objective was to evaluate the influence of dental metallic artefacts on implant sites using multislice and cone-beam computed tomography techniques. Ten dried human mandibles were scanned twice by each technique, with and without dental metallic artefacts. Metallic restorations were placed at the top of the alveolar ridge adjacent to the mental foramen region for the second scanning. Linear measurements (thickness and height) for each cross-section were performed by a single examiner using computer software. All mandibles were analysed at both the right and the left mental foramen regions. For the multislice technique, dental metallic artefact produced an increase of 5% in bone thickness and a reduction of 6% in bone height; no significant differences (p>0.05) were detected when comparing measurements performed with and without metallic artefacts. With respect to the cone-beam technique, dental metallic artefact produced an increase of 6% in bone thickness and a reduction of 0.68% in bone height. No significant differences (p>0.05) were observed when comparing measurements performed with and without metallic artefacts. The presence of dental metallic artefacts did not alter the linear measurements obtained with both techniques, although its presence made the location of the alveolar bone crest more difficult.

Diabetes modulates gene expression in the gingival tissues of patients with chronic periodontitis.

AIM: This study evaluated whether diabetes modulates gene expression [interleukin (IL)-1beta, IL-1ra, IL-6, IL-8, IL-10; tumor necrosis factor (TNF)-alpha; interferon (IFN)-gamma, receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG)] in sites with periodontitis. MATERIALS AND METHODS: Gingival biopsies were harvested and divided into three groups--Control group: systemically and periodontally healthy subjects (n = 10); Periodontitis group: systemically healthy subjects diagnosed with chronic periodontitis (n = 20); Diabetes group: type 1 diabetic subjects, diagnosed with chronic periodontitis (n = 20). Total RNA was obtained and analyzed by quantitative polymerase chain reaction. RESULTS: Data analysis demonstrated that, except for OPG, mRNA levels for all factors were increased by inflammation (P < 0.001). Interleukin-1beta, IL-1ra, IL-6, IL-8, IFN-gamma, and RANKL mRNA levels were higher in the diabetic group when compared with the control non-periodontitis group (P < 0.05), whereas IL-10 and OPG were lower (P < 0.05). No difference was observed for TNF-alpha between diabetic and control groups (P > 0.05). Diabetes lowered IL-1beta, IL-8, IL-10, TNF-alpha, RANKL, and OPG mRNA levels in sites with comparable type of periodontitis (P < 0.001). Moreover, increased RANKL:OPG and IL-6:IL-10 ratios were found. CONCLUSION AND CLINICAL RELEVANCE: Taken together, these data suggest that decreased levels of IL-10 and OPG may play an important role in the periodontal breakdown in diabetic patients.

Periodontal healing may be affected by aging: a histologic study in rats.

BACKGROUND AND OBJECTIVE: Although wound healing has been reported to be impaired with aging, very little is known about its effect on periodontal tissues. Therefore, the aim of this study was to evaluate, histologically in rats, the influence of aging on a spontaneous periodontal healing model. MATERIAL AND METHODS: Twenty-four male Wistar rats were used and assigned to the following groups: control (n = 12; 2 mo old) and aged (n = 12; 18 mo old). Fenestration defects (4 x 3 x 1 mm) were created bilaterally at the buccal aspect of the distal root of the first mandibular molars, and the mandibulae were retrieved 3 and 6 wk postoperatively. The percentage of bone fill and density of newly formed bone, new cementum formation (NC), and the extension of the remaining defect (ERD) were histometrically obtained. RESULTS: Intragroup analysis demonstrated that, except for cementum, all histological parameters significantly improved over time (p < 0.05). Intergroup analysis additionally showed that the defects were initially similar in size, and that at 3 wk aging negatively influenced newly formed bone (86.38 +/- 2.99% and 73.06 +/- 3.21%, p < 0.001, for groups control and aged, respectively), BF (75.84 +/- 16.53% and 57.70 +/- 22.28%, p = 0.014) and ERD (0.41 +/- 0.20 mm and 1.17 +/- 0.37 mm, p < 0.001). At 6 wk, aging negatively influenced newly formed bone (88.12 +/- 2.90% and 78.19 +/- 5.35%, p < 0.001, for groups control and aged, respectively) and ERD (0.01 +/- 0.006 mm and 0.34 +/- 0.18 mm, p = 0.003), but not BF (98.15 +/- 2.43% and 87.87 +/- 11.63%, p > 0.05). No new cementum was formed along the root surface in the above groups. CONCLUSION: Within the limits of the present study, data analysis suggests that aging may impair, but not prevent, periodontal healing.