HISTOLOGICAL STUDY OF THE EFFECT OF HYPERVITAMINOSIS "A" ON HEALING OF SURG[CALLY DRILLED MANDIBULAR BONE DEFECT AND CONDYLAR GROWTH IN ALBINO RATS

Abstract

The current investigation was conducted to evaluate the effect of hypervitaminosis A on the healing of surgically drilled mandibular bone. defect as well as the histological structure changes in growing condyle in albino rats.

The study was conducted on forty growmg albino rats aged 2 months (the newborn rats corresponds to a 16- week old human fetus). The rats were divided equally into control and experimental groups. Non­ critical sized bone defects were surgically created in both groups 3mm away from the inferior border of the mandible with respect to first mandibular molar teeth.

Vitamin A palmitate was g1ven to the experimental group by intraoral route, in a dose of 15 mg RE/ rat. The dose was dissolved in 0.2ml corn oil and given 3 times/ week for 1,2,3,4 and 6 weeks

respectively beginning from the day of surgery. The control group was

-dosed only with 0.2ml corn oil per dose as in the experimental group.

Each group was further classified. according to the time •of euthanzia into 5 subgroups (4 rats each):

W1 group

w2 group w3 group w4 group w6 group

(One week postoperatively) (Two weeks postoperatively) (Three weeks postoperatively) (Four weeks postoperatively) ( Six weeks postoperatively) •

At the time of euthanzia, the heads of the animals were prepared to be used for histological and histomorphometric studies.