Comparison of two methods for alveolar bone loss measurement in an experimental periodontal disease model in rats

There are many studies that evaluate possible risk factors for periodontal diseases in animals. Most of them have focused only on the biological aspects of disease occurrence; therefore, it has been difficult to compare studies of the different methodological approaches. The aim of the present study was to compare different methods - linear and area - of the evaluation of morphometrical alveolar bone loss. Sixty hemimaxillae, defleshed and stained with 1 percent methylene blue to delineate the cementoenamel junction and alveolar bone crest, were obtained from a previous study that induced periodontal disease by means of ligatures in two groups of fifteen Wistar rats during 9 weeks. Ligatures were placed around the right upper second molars, and the contra-lateral teeth remained as intra-group controls. Digital photographs were taken from the specimens and submitted to a single, calibrated, blind examiner who performed the morphometrical evaluation of alveolar bone loss using both linear and area methods. Mean values of linear and area measurements were obtained from each side - buccal and palatal - of the specimens. The degree of association between the two methods was determined by Pearson's Correlation Coefficient. An almost perfect association (0.98) was determined between the linear and area evaluations. A mathematical formula was subsequently created to estimate the total area of alveolar bone loss, from linear mean measurements. Both methods were suitable for detecting bone level alterations. The results of the present study allow for the transformation of data and better compilation of results from different studies.

Comparison of two methods for alveolar bone loss measurement in an experimental periodontal disease model in rats.

There are many studies that evaluate possible risk factors for periodontal diseases in animals. Most of them have focused only on the biological aspects of disease occurrence; therefore, it has been difficult to compare studies of the different methodological approaches. The aim of the present study was to compare different methods - linear and area - of the evaluation of morphometrical alveolar bone loss. Sixty hemimaxillae, defleshed and stained with 1% methylene blue to delineate the cementoenamel junction and alveolar bone crest, were obtained from a previous study that induced periodontal disease by means of ligatures in two groups of fifteen Wistar rats during 9 weeks. Ligatures were placed around the right upper second molars, and the contra-lateral teeth remained as intra-group controls. Digital photographs were taken from the specimens and submitted to a single, calibrated, blind examiner who performed the morphometrical evaluation of alveolar bone loss using both linear and area methods. Mean values of linear and area measurements were obtained from each side - buccal and palatal - of the specimens. The degree of association between the two methods was determined by Pearson's Correlation Coefficient. An almost perfect association (0.98) was determined between the linear and area evaluations. A mathematical formula was subsequently created to estimate the total area of alveolar bone loss, from linear mean measurements. Both methods were suitable for detecting bone level alterations. The results of the present study allow for the transformation of data and better compilation of results from different studies.

Low concentration alcohol intake may inhibit spontaneous alveolar bone loss in Wistar rats.

OBJECTIVE: The aim of the present study was to evaluate the influence of ethanol in low concentration (5%) in ligature-induced alveolar bone loss in Wistar rats. MATERIAL AND METHODS: Thirty rats were randomly assigned to test and control groups (n=15). Test group received a liquid diet containing ethanol 5% (vol./vol.) and standard rat chow. Control group received only tap water as the liquid diet and the same rat chow. In both groups, diet was delivered ad libitum. Alveolar bone loss was induced prior to the beginning of the study by means of ligatures placed around the upper second molars. The contra-lateral tooth remained as intra-group control. At the end of the nine weeks, the animals were killed and morphometric analysis of alveolar bone loss was performed by a blinded and calibrated examiner. Intra-group comparisons were performed by paired sample T-test and inter-group differences were compared by independent sample T-test (α=.05). RESULTS: Animals that drank ethanol in low concentration systematically presented less alveolar bone loss than the control group, regardless of the presence of ligature. Test group showed less alveolar bone loss (p=0.04) in unligated teeth when compared to control group (0.32 ± 0.07 and 0.37 ± 0.07 mm, respectively). However, no significant difference (p=0.14) was observed between Test and Control groups (0.78 ± 0.14 and 0.84 ± 0.18 mm, respectively) in ligated teeth. CONCLUSION: The results of this study lead to the conclusion that low concentration alcohol intake did not affect the alveolar bone loss in ligature induced periodontal breakdown.