Photoplethysmographic Diagnosis for Marginal Periodontitis

点击翻译按钮获取中文摘要

Gingival inflammation accompanies disorder of local circulation. Therefore there exists a possibility for detecting inflammatory condition by observing gingival blood flow. The purpose of this study is to establish a method to record the photoplethysmographs from small gingival areas and to estimate gingival inflammatory stages by comparing the wave forms with those from normal area.Preliminary investigations were carried out to determine conditions for recording. A tungsten lamp connected to a stabilized power supply was used as the light source. A fiber optic bundle of 2 mm diameter was fixed to the adjacent tooth using an acrylic adapter. The bundle consisted of illuminating and recording fibers which were arranged randomly. A CdSe photoconductive cell was used as the photosensor. Simultaneous recording of the ECG was made and the recorded QRS spikes were used as the triggers for averaging the record. To record transilluminated plethysmographs, the outlet of the illuminating bundle was arranged lingually. In case of reflected photoplethysmographs, both the recording and illuminating fibers were placed tabially.When the bundle was placed close to the gingiva, dicrotic notches were cleatly observed both on transilluminated and reflected plethysmographs. Covering the surface of gingiva with white opaque paint resulted almost the same wave forms as transilluminated ones in reflected photoplethysmographs. To reject the 100 Hz noise from fluorescent lights at clinic, a sheet of aluminum foil was used around the recording site.Experiments were in progress to analyze the characteristics of photoplethysmographs recorded from inglamed gingiva and to relate the findings to other periodontal diagnostic parameters.The photoplethysmographs recorded from patients with marginal perjodontitis were smaller amplitude with less clear dicrotic notches than those recorded from normal gingiva.