Long term effect of tricyclic antidepressant drugs of the periodontium of albino rats

Tricyclic antidepressants, are used for treatment of depression, nocturnal enuresis, trigeminal neuralgia, headache and parkinsonism. The complications associated with the use of the drug include restlessness, malaise, delerium, agranulocytosis, fever, sore throat, dry mouth, constipation, hypotension, tacchycardia and mydriasis with blurred vision. Since the drug may be used for a long period in a high or low doses according to the severity of the condition, so the aim of the present investigation was to study the long term effect of high and low doses of tricyclic antidepressant drugs [Amitriptyline hydrochloride] on the periodontium of albino rats. The study was performed on 36 male albino rats divided into two experimental groups, 15 rats for each, and one control group consisted of 6 rats received intra-muscular injection of saline. The first experimental group [low dose group] received intramuscular injection of 1.35 mg/day of Amitriptyline hydrochloride, while the second experimental group received intra-muscular injection of 2.7 mg/day of the same drug. Two rats of the control group as well as five rats of each experimental group were sacrified at the end of the first, second and third months respectively from the begining of the experiment. Maxillary and mandibular specimens were dissected, fixed, sectioned and stained with H. and E. and Examined microscopically. Slight increase was shown in collagen fibres without any consistent pattern with no changes in thickness of the periodontal ligament at the end of the third month in the group received low dose of the drug. On the other hand, for the high dose group an increase in the periodontal ligament thickness was noted with marked proliferation of collagen bundles and some fragmented areas of the alveolar bone. It was concluded that the drug has a stimulating action on fibrous tissue synthesis of the gingival fibres and periodontal ligament. Fragmentation of the alveolar bone may be related to excessive pressure induced by the proliferating collagen fibres and/or the impairement of the blood supply to the alveolar bone. There was no evidence of chronic inflammatory cell infiltration in the connective tissue or gingival epithelial degeneration which proved that the changes were not dependent on local irritating factor. The proliferation of the junctional epithelium appeared to be hindered by the firm attachment of the dense collagen fibres to the root surface giving no chance for periodontal pocket formation