Résumé
The present study was carried out on 50 oral Lichen planus patients in an attempt to throw light on the interesting association of oral lichen planus and diabetes mellitus.They were subjected to: 1. Clinical examination 2. Glucose tolerance test 3. Histopathological study 4. Histochemical study of glycogen and succinic dehydrogenase enzyme. According to glucose tolerance test 64% of studied patients had abnormalities in glucose metabolism, with diabetes mellitus was diagnosed in 28% of them.The incidence of diabetes mellitus in patients with oral lichen planus showed predilection towards males and old age. It was directly proportional to remission and exacerbation of the lesions. The histopathological difference between diabetic, potentially diabetic and non- diabetic oral lichen planus lesions was found to be non specific where only the epithelial atrophy and ulceration were found to be more common in diabetic cases while signs of dysplasia were found to be more common in non- diabetic cases. Histochemically, there was decreased glycogen content of tissues involved by oral lichen planus lesions with the degree of glycogen reduction was found to be more marked in diabetic than in non diabetic cases As regard succinic dehydrogenase, it showed decreased activity within the epithelium, especially in the basal cell layer, of oral lichen planus lesions and the degree of enzyme reduction was found to be the same among diabetic, potentially diabetic and non-diabetic lesions.From this study, we concluded that there is an association between oral lichen planus and diabetes mellitus without significant histopthological difference between the lesions of diabetic and non-diabetic patients