Periodontal pocket clearance by gamma scintigraphy in human volunteers

Background: With the interest in the delivery of drugs to the periodontal p ocket has come an increased need to determine the loss of formulations from the site of application. In this respect, gamma scintigraphy has been used to measure formulation clearance in mucosal sites such as the oesophagus, nose and eyes by assessing the persistence of an incorporated radiolabel. H owever, the technique has not been used to follow clearance from the period ontal pocket. Aims: The aim of this study was therefore to assess the potential of gamma scintigraphy to follow the loss of 2 contrasting formulations. 10% chitosan gel and normal saline. Method: Technitium-99m was used as the radionuclide and was incorporated in to the formulations on the day of use. 9 subjects contributed up to 2 pocke ts for each formulation with probing depths greater than or equal to5 mm. Results: The results demonstrated that gamma scintigraphy was able to follo w the loss of the radiolabel despite the small volumes of formulation place d in situ. The mean (SD) times (min) for the original counts to decline to 10%, 50% and 90% of the original values were: T10: chitosan 74.5 (59.0), sa line 40.3 (21.1), T50: chitosan 41.5 (34.1) saline 20.8 (11.7) and T90: chi tosan 8.5 (10.8), saline 1.4 (3.7) respectively. Clearance times of the 2 f ormulations were significantly different from each other (p<0.05). Conclusion: In conclusion, gamma scintigraphy is a sensitive method for ass essing clearance from the periodontal pocket, and further studies are merit ed to optimise the use of the technique.