Morphological characteristics of the depository surface of alveolar bone of diabetic mice

Evaluation of thickness of cementum of periodontally diseased teeth of non-diabetic and type 2 diabetic patients: A scanning electron microscopy study

Background:

It is suggested that diabetes plays an important role in tooth loss. The periodontal structure and alveolar bone architecture in diabetics have revealed alterations. However, changes in cementum of diabetics with periodontal disease have not been evaluated adequately. Thus, the aim of the study is to evaluate and compare the thickness of cementum in diseased and healthy areas of roots of teeth with chronic periodontitis from non-diabetic (group I) and type 2 diabetic patients (group II).

Materials and Methods:

Thirty incisors indicated for extraction as a result of chronic periodontitis from group I and group II were selected. Measurements of Probing Depth (PD) and Clinical Attachment Loss (CAL) were taken prior to extractions. Area of the root surface above the CAL (notch) was designated as diseased, while the area below the CAL (notch) was designated as healthy. The extracted tooth samples were sectioned longitudinally and were evaluated by scanning electron microscopy (SEM). Descriptive statistical analysis was performed. Results of continuous measurements were presented as Mean ± SD.

Results:

The results showed that in both groups the thickness of cementum in diseased areas was lower in comparison to the thickness in healthy areas. The mean thickness of cementum in both healthy and diseased areas was higher in group II compared to group I, though the differences in both were not statistically significant.

Conclusion:

Within the limits of the present study, group II showed greater mean thickness of cementum in both healthy and diseased areas compared to group I, though the differences were not statistically significant.

Alloxan-induced diabetes triggers the development of periodontal disease in rats

Background

Periodontal disease in diabetic patients presents higher severity and prevalence; and increased severity of ligature-induced periodontal disease has been verified in diabetic rats. However, in absence of aggressive stimuli such as ligatures, the influence of diabetes on rat periodontal tissues is incompletely explored. The aim of this study was to evaluate the establishment and progression of periodontal diseases in rats only with diabetes induction.

Methodology/Principal Findings

Diabetes was induced in Wistar rats (n = 25) by intravenous administration of alloxan (42 mg/kg) and were analyzed at 1, 3, 6, 9 and 12 months after diabetes induction. The hemimandibles were removed and submitted to radiographical and histopathological procedures. A significant reduction was observed in height of bone crest in diabetic animals at 3, 6, 9 and 12 months, which was associated with increased numbers of osteoclasts and inflammatory cells. The histopathological analyses of diabetic rats also showed a reduction in density of collagen fibers, fibroblasts and blood vessels. Severe caries were also detected in the diabetic group.

Conclusions/Significance

The results demonstrate that diabetes induction triggers, or even co-induces the onset of alterations which are typical of periodontal diseases even in the absence of aggressive factors such as ligatures. Therefore, diabetes induction renders a previously resistant host into a susceptible phenotype, and hence diabetes can be considered a very important risk factor to the development of periodontal disease.

Relationship Between Periodontitis and Diabetes: Lessons From Rodent Studies

BACKGROUND

A great amount of investigations have provided evidence that both type 1 and type 2 diabetes increase the risk and severity of periodontitis; several alterations in the diabetic periodontium are likely to be involved. Conversely, periodontitis has been shown to have an impact on diabetes, although less evidence is available on the underlying mechanisms. The association between periodontitis and diabetes has been discussed in several reviews over the past years; however, none has focused on the use and contribution of rodent models.

METHODS

This review describes the most commonly used rodent models of diabetes, periodontitis, and the association between the two diseases. Further, we summarize the influence of diabetes in the periodontium as well as the effect of periodontitis on diabetes status with special focus on evidence from experimental studies.

RESULTS

Rodent studies have confirmed human findings and further increased our knowledge on the alterations in the diabetic periodontium. On the other hand, few rodent investigations have explored the consequences of periodontitis for diabetes. Their results clearly indicate that periodontitis can become a health hazard not only for diabetes but also for prediabetes; the exact mechanisms are still to be unraveled.

CONCLUSIONS

Findings from rodent studies have been useful in increasing our understanding of periodontitis, diabetes, and their association and hold great promise for future investigations given the wide variety of possibilities for testing biologic hypotheses.

Indentation modulus of the alveolar process in dogs

One mechanism of bone adaptation is alteration in tissue level material properties. We hypothesized that alteration in the indentation modulus of the alveolar process is an adaptive response to the localized mechanical environment. Forty-eight specimens representing anterior and posterior regions of the maxilla and mandible were obtained from 6 mature male beagle dogs. The indentation properties of the alveolar bone proper and more distant osteonal cortical bone were estimated. The bone types were further divided into 3 regions (coronal, middle, and apical), with 27 indents being made in each region of tooth-supporting bone. There was a significant difference (p < 0.001) in the indentation moduli of the jaws (maxilla/mandible), location (anterior/posterior), and bone type (alveolar bone proper vs. cortical bone). However, statistical interactions exist which preclude the simple interpretation of results. The distribution of relative stiffness provides a better understanding of bone adaptations in the alveolar process.

Effect of streptozotocin-induced diabetes mellitus on alveolar bone deposition in the rat

Effects of diabetes on alveolar bone remodelling were assessed by quantitative histology and a chronological lead-labelling technique. Experimental diabetes was induced by a single dose of 40 mg/kg of streptozotocin. Remodelling of the alveolar wall surrounding the root of mandibular first molar was studied in control rats fed ad libitum, and in diabetic and insulin-treated diabetic rats 24 days after the induction of diabetes. The volumes of bone formation on the mesial side of the alveolar wall were evaluated over a 10-day period by chronological lead-labelling and computer image analysis. For a histometric measure of bone-resorption, the number of osteoclasts along the distal surface of the alveolar wall was counted. The volume of bone formed and the number of osteoclasts were significantly lower in the diabetic rats than in the controls, but insulin treatment of diabetic rats normalised these histomorphometric measures of bone turnover. These results demonstrate that streptozotocin-induced diabetes mellitus reduces the rate of bone turnover in the alveolar wall surrounding the root, which reduction is corrected by treatment with insulin.