Photoplethysmographic Diagnosis for Marginal Periodontitis

牙龈炎症伴局部循环紊乱。因此，有可能通过观察牙龈血流来检测炎症状况。本研究的目的是建立一种记录牙龈小区域光容积脉搏波的方法，并通过与正常区域的波形比较来估计牙龈炎症的分期。进行了初步调查，以确定记录的条件。光源采用钨丝灯连接稳定电源。使用丙烯酸接头将直径2mm的光纤束固定在相邻的牙齿上。该束由随机排列的照明和记录纤维组成。采用CdSe光导电池作为光传感器。同时记录心电图，并将记录的QRS尖峰作为记录平均的触发器。为了记录透照容积描记，光照束的出口呈舌状排列。在反射式光电容积仪中，记录纤维和照明纤维都被平放。当束靠近牙龈放置时，在透照和反射容积描记仪上都能清楚地观察到双致凹痕。用白色不透明涂料覆盖牙龈表面，在反射光容积描画中得到的波形与透射光描画的波形几乎相同。为了抑制诊所荧光灯发出的100赫兹噪音，录音地点周围使用了一张铝箔。实验正在进行中，以分析从镶嵌牙龈中记录的光容积脉搏波特征，并将结果与其他牙周诊断参数联系起来。边沿性牙周炎患者的光容积脉搏波比正常牙龈的振幅小，双凸沟不明显。

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.