Photoplethysmographic Diagnosis for Marginal Periodontitis

牙周炎伴发局部循环障碍。因此，通过观察牙周血流来检测炎症状态是可能的。本研究的目的是建立一种记录小型牙周区的光体积图的方法，并通过与正常牙周区的波形进行比较来判断牙周炎的分期。光源是一盏连接到稳定电源的钨灯。用亚克力适配器将直径为2 mm的光纤束固定到相邻牙齿上。该束由随机排列的照明纤维和记录纤维组成。光敏传感器采用了CdSe光导电池。同时记录心电，记录的QRS峰被用作记录平均化的触发因素。为了记录透光的体积脉搏图，照明束的出口被舌状布置。在反射式光体积描记器中，记录纤维和照明纤维都放置在桌子上，当记录纤维和照明纤维放置在靠近牙龈的位置时，在透射式和反射式体积描记器上都清晰地观察到二向分叉的凹痕。用白色不透明涂料覆盖牙周表面，在反射光体积图上得到与透光的波形几乎相同的波形。为了消除临床上荧光灯发出的100赫兹噪声，在记录部位周围使用了一张铝箔。实验正在进行中，分析从牙周组织记录的光体积图的特征，并将结果与其他牙周诊断参数相关联。边缘牙周炎患者记录的光体积图比正常牙龈记录的光体积图幅度小，分叉缺口不明显。

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.