利用自体荧光成像量化分析牙菌斑

牙菌斑是造成龋病及牙周病的主要因素之一，通过检测牙齿表面牙菌斑含量多少能在一定程度上了解牙齿健康程度，对口腔健康的维护有重要意义。利用牙菌斑与牙齿组织自体荧光光谱的差异性，本文设计了一套便携式的基于自体荧光成像的检测系统。(1)该系统以中心波长为405 nm的LED作为激发光源，辅以中心波长520 nm的长波通滤光片提高系统信噪比，CCD作为感光器件；系统采集荧光图像后，根据成像结果分析牙面上牙菌斑含量。(2)设计了验证实验采集受试者牙齿图像，并以牙菌斑百分比作为量化牙菌斑多少的指标。实验结果表明荧光图像菌斑百分比与Turesky改良的Quigley-Hein菌斑指数的Spearman等级相关系数为0.944，牙齿荧光图像牙菌斑百分比与染色图像牙菌斑百分比的Pearson相关系数为0.875。由此可见，文中的检测系统具有较好的准确性，而且因为采用光学检测方法，具有非侵入性且可重复性，所以它有广阔的临床应用前景，有望成为家用口腔健康的检查手段。

Quantification of Dental Plaque Based on Auto-Fluorescence Imaging

Dental plaque is one of the main etiologic factors that lead to dental caries and periodontal disease,and the amount of plaque on teeth could be served as reference for the teeth health condition to some extent.Therefore,the detection of dental plaque plays a very important role for maintaining the oral health.However,identification of dental plaque is difficult for both patient and dentist because the tooth and dental plaque often look similar,especially when plaque is present in scanty amounts.Excited by the light source with the wavelength of 405 nm,the auto-fluorescence effect will appear in both dental plaque and dental tissue,but the auto-fluorescence spectrum of dental tissue mainly locates at the wavelength range of blue and green light,while the auto-fluorescence spectrum of dental plaque mainly locates at the wavelength range of red light,and the spectrum intensity caused by the different leveled dental plaque are also diverse.Based on the differences between auto-fluorescence spectra of dental pla que and dental tissues,a potable auto-fluorescence color imaging dental plaque detection system was developed.In the detection system,five surface-mounted LEDs whose central wavelength are all 405 nm are assembled as the excitation source,besides,a long pass optical filter with central wavelength of 520 nm is configured to improve the signal to noise ratio (SNR),and the excited auto-fluorescence was collected and imaged through the imaging lens to the array sensor of a color CCD with a resolution of 640×480.Finally,the amount of dental plaque is analyzed by processing the captured fluorescence images.An experiment was designed to confirm the reliability of the detection system.The anterior teeth auto-fluore Sscence images of seven recruited subjects with various mounts of dental plaque were captured by the system,after the subjects chewed the disclosing agent for 1minute and rinsed their mouth with 100 mL distilled water,the Quigley Hein plaque index (PI) modified by Tureksy and disclosing images were both recorded.The plaque percent index (PPI) which is defined as the proportion of the dental plaque area and entire teeth surface area.The statistic analysis shows:The Spearman rank correlation coefficient between the PPI of fluorescence image and the PI is 0.944,and the Pearson correlation coefficient between PPI of fluorescence image and PPI of disclosing image is 0.875.PPI of fluorescence image has an increasing trend with increase in plaque grade and the PPI show statistically significant differences (p<0.01) between different grades.As conclusions,the proposed noninvasive detection system using the optical detecting approach ensures a fairly good accuracy and reliability,besides,the evaluation index of the PPI is more precise compared with the PI.We envision it has the potential to be a homecare practice and convince people of the demand for proper oral hygiene.