Bone Abstracts

Aim: Study the features changes of histomorphometric parameters of alveolar ridges in immature rats after thymectomy.

Methods: The study was conducted on 120 immature male rats were divided into two groups: 1st group – sham-operated animals, 2nd group – rats with removed of the thymus under mask ether anesthesia (thymectomy). Periods of observation were 7, 15, 30, 90 and 180 days. Rats were euthanized under mask ether anesthesia. For histological examination the mandible was cut at the level of the second molar, separated dentoalveolar segments were fixed in 10% neutral formalin, decalcified in 5% formic acid, dehydrated in increasing concentrations of alcohol, embedded in paraffin and stained with hematoxylin–eosin. Morphometry program included the following parameters: the total width of the alveolar ridge at the level of 2nd molar and the width of its layers: the outer cortical plate, inner cortical plate, osteon layer and diameters of osteons and their channels.

Results: In animals of 2nd group the total width of the alveolar ridge and the width of the outer cortical plate decreased, compared with the same parameters in 1st group, from 30 to 180 day of observation respectively by 3.55, 7.13, 8.89 and 5.44, 8.71, 9.41%, width of osteon layer – by the 90th and the 180th days by 8.83 and 9.28% and the width of the inner cortical plate – by the 180th day by 7.87%. Diameters were lower than those of 1st group by the 90th and 180th days of observation by 4.35 and 4.46%, and the diameter of osteons channels, in contrast, were more by 8.46 and 15.88% respectively.

Conclusions: Thus, under conditions of thymectomy in immature rats there was a disturbance in the structural organization of alveolar ridge of the mandible in the later period of observation (from 30 to 180 per day), which may indicate a generalized periodontitis.