Ultrastructural determination of gingival Langerhans cells in alloxan-induced diabetic rats.

The ultrastructure of Langerhans cells has not been fully investigated in diabetes-associated gingival tissues. The present study was carried out to investigate the ultrastructure of gingival Langerhans cells in alloxan-induced diabetic rats. Gingival biopsies were obtained from 22 diabetic and 18 control rats. Langerhans cells were observed by transmission electron microscopy (TEM) in the basal layers of healthy oral epithelium. On rare occasions, Langerhans cells were found in the suprabasal layers of the oral epithelium. Langerhans cells in the oral epithelium of diabetic rats were seen in the basal and suprabasal layers. Usually, Langerhans cells had clear cytoplasm and convoluted or indented nuclei and few or no specific granules. The clear cytoplasm contained mitochondria, lysosomes and a small number of rough-surfaced endoplasmic reticulum regions, but it lacked tonofilament. Occasionally, centrioles were also observed in the cytoplasm. The membrane of Langerhans cells had no junctional complexes such as desmosomes. In diabetic rats, Langerhans cell precursors were developed into specific granule-bearing cells. Both Langerhans cells and their granules were more frequent in the gingiva of diabetic rats than in the control group. These data suggest that Langerhans cells play an important role in explaining the pathogenesis and development of diabetic gingivitis.

The investigation of the ultrastructural neutrophil changes in alloxan-induced diabetes in rats: response to a chemotactic challenge.

Experimental diabetes is one of the most popular conditions in which to study the relation between neutrophil leukocyte activity and periodontal destruction. The aetiology of neutrophil dysfunction in the gingival tissue associated with diabetes has yet to be clarified. Diabetes in rats decreases neutrophil chemotactic activity in proportion to the severity of this systemic disorder. The present study was carried out to evaluate the relationship between the severity of diabetes and the neutrophil response to two chemotactic agents, and to correlate the observed neutrophil defects with the degree of diabetes. In this study two chemotactic agents, casein (0.2 microl, 2 mg ml(-1)) or N-formylmethionylleucylphenylalanine (FMLP; 0.2 microl, 10(-4) M), were placed into the gingival crevices of alloxan-induced diabetic rats. Gingival biopsies were taken 15 min later and then at 5-min intervals up to 45 min and investigated by electron microscopy. Adherence and migration were observed in the rats with moderate diabetes 30 min after the application of casein. There was chemotaxis after 35 min of administration of the peptide FMLP. By 40 min neutrophils with pyknotic nuclei were observed. At 45 min neutrophils with a decreased number of granules were present. As the severity of the diabetes increased, the neutrophils degenerated and were structurally distorted. In the rats which had alloxan-induced diabetes there was abnormal periodontal damage. This damage is thought to be related to dysfunctional neutrophils. These findings many contribute to an answer to the following question: why is there an apparent variability in the susceptibility of periodontal breakdown in diabetics?

A histopathological investigation on the effect of systemic administration of the bisphosphonate alendronate on resorptive phase following mucoperiosteal flap surgery in the rat mandible.

BACKGROUND: The present study was designed to assess histopathologically whether the systemic administration of aminobisphosphonate (alendronate), 0.5 mg/kg body weight, is effective in preventing alveolar bone resorption following mucoperiosteal flap surgery, and whether alendronate modulates tissue factors. METHODS: The effect of alendronate on bone resorption was evaluated in mucoperiosteal flaps used as a resorptive model. The animals were given subcutaneous injections of either saline (control group) or 0.5 mg/kg of alendronate (experimental group). The alendronate or saline was administered subcutaneously 1 week prior to surgery, immediately prior to surgery, and 1 week after surgery. The parameters determined with a semiquantitative subjective method for histopathological evaluation were as follows: inflammatory cell infiltration (ICI) of adjacent periodontal tissue, degree of fibrosis and collagen bundle formation, number and morphology of osteoclasts of the alveolar bone and interdental septum, resorption lacunae (osteoclast surfaces), and osteoblastic activity (forming surfaces). RESULTS: There were no statistically significant differences between the saline and alendronate groups with regard to inflammatory cell infiltration, number of osteoclasts, and osteoblastic activity. Fibrosis and collagen bundle formation, osteoclast morphologies, and resorption lacunae formation were significantly different between the two groups, in favor of the alendronate group. CONCLUSIONS: The systemic administration of 0.5 mg/kg alendronate was effective in preventing alveolar bone loss and in modulating tissue factors. These findings indicate that alendronate would be a valuable addition to the therapeutic armamentarium available for the treatment of periodontal diseases, either alone or in combination with regenerative components such as anti-inflammatory drugs, bone graft materials, and guided tissue regeneration techniques, and even with dental implants.

Evaluation of non-surgical periodontal treatment using 2 time intervals.

BACKGROUND: The aim of the present study was to evaluate the effectiveness of non-surgical mechanical instrumentation at 2 different time intervals on short-term healing and to assess patient reactions following non-surgical periodontal therapy. METHODS: The study population consisted of 100 patients with moderate periodontal disease. Patients were equally distributed into 2 groups, treated daily or weekly. The daily group received full-mouth daily scaling and root planing for 4 consecutive days. The weekly group was treated once a week for 4 weeks. All patients were asked for objective (lymphadenopathy, aphthous stomatitis, and edema) and subjective (fatigue, pain, pruritus, burning sensation, and dentinalgia) reactions. Clinical measurements of plaque index (PI), gingival index (GI), probing depth (PD), bleeding on probing (BOP), and gingival recession (GR) were taken at baseline and 3 months after treatment. All of the objective and subjective reactions were recorded after each treatment session. RESULTS: The results of our study revealed a significant decrease in PI, GI, BOP, and PD measurements at the end of the third month, but no significant changes in GR. The incidence of subjective and objective reactions was higher in the daily treated group compared to those in the weekly group. Most of these complaints were observed after the third treatment session. CONCLUSIONS: Within the limits of this study, no differences were observed between the study groups when the clinical parameters were evaluated. However, taking the subjective and objective reactions into consideration, the smallest time interval for non-surgical periodontal procedures might be 1 week.