Relationship Between Vibration Of Maxillary Anterior Teeth And The Level Of Periodontal Attachment

Periodontal disease is very common in the clinic, and serious damage to oralhealth. Periodontal disease is a systemic disease caused by multiple factors. Theaccumulation of plaque is the initiating factor of periodontal disease, the defensemechanisms of regulation and other systemic diseases can also lead toperiodontal disease. At present, probing and X-ray are the primary means ofclinical diagnosis of periodontal disease, but in recent years some studies havequestioned the accuracy of traditional diagnosis. In order to improve thedrawbacks of traditional periodontal diagnosis, the scholars in the study of newtechnologies have done a lot of works, but the new means of detection wasrelatively cumbersome operation, the price is also higher, which limited itsclinical application.Vibration was a nature phenomenon of object and different structure withdifferent features. The vibration is closely related to the elastic modulus,density,Poisson’s ratio and boundary condition. In the oral, the teeth with periodontalligament and alveolar bone are established a vibration system, and external forcewill produce vibration phenomenon. The vibration characteristics of the teeth isalso influenced by the condition of the periodontal ligament and alveolar bone. In clinical, the natural frequency of the teeth changed.,according to the impact oforal diseases,such as caries and periodontal diseases, which make the toothstructure and periodontal tissue destruction,To investigate the relationship between periodontal attachment level andvibration frequency of maxillary anterior teeth, vibration of maxillary anteriorteeth was recorded by using a accelerometer. The acceleration was transformedinto frequency by Fourier Transform. Periodontal attachment level of the sameteeth was measured. In order to simulate the vibration of maxillary anteriorteeth.Finite element model of maxillary anterior teeth and periodontal tissueswere established at the same time, The relationship between vibration frequencyand periodontal attachment level was investigated as well.All the study can be divided into four parts.1. Determination of the level of periodontal attachment to the volunteers:Selecting experimental volunteers based on inclusion criteria. Volunteersgot periodontal treatment before the experiment. The result of X-ray andperiodontal probe determined the volunteers were divided into four groups. Fourgroups of periodontal attachment loss levels were0-1mm，2-3mm，4-5mm and≥6mm.2. The measurement of vibration frequency to maxillary anterior teeth:Vibration of different periodontal attachment of maxillary anterior teeth wasrecorded by using accelerometer. The acceleration was transformed intofrequency by Fourier Transform. Periodontal attachment level of the same teethwas measured. The results were analyzed by using SPSS10.0software.3. The effects of added mass of accelerometer on vibration frequency:In vibration system, the frequency of the object is closed to it’s quality. Inorder to reduce the effects of the additional mass of accelerometer, formula was 1used to eliminate the additional mass of accelerometer. The results wereanalyzed by using SPSS10.0software4. Finite element analysis of the vibration to the maxillary anterior teeth:On the basis of the above study, finite element model of maxillary anteriorteeth and periodontal tissues was established, which was corresponded to theclinical trials. MARC software is used to analyze the vibration of finite elementmodel of maxillary anterior teeth with different periodontal attachmentThe results of this study showed as following.1. After a rigorous screening of clinical, there were262maxillary anteriorteeth were measured, According to attachment level, the teeth were divided into0-1mm,2-3mm,4-5mm and>6mm groups. The four groups were reflected thedifferent level of periodontal attachment.2. The mean frequency values of these groups were904.57±39.31HZ,761.14±29.10HZ,513.35±50.13HZ and335.29±67.89HZrespectively. Thestatistical analysis showed that there were differences between the vibrationfrequency values of four groups (P <0.01).There existed a positive correlationbetween vibration frequency and periodontal attachment level of maxillaryanterior teeth.3. The additional mass of the accelerometer on the vibration frequency had aclear impact. Four groups using the formula to eliminate the additional mass ofthe accelerometer vibration frequency value was904.57±39.31Hz,761.14±29.10Hz,513.35±50.13Hz,335.29±67.89Hz, The statistical analysisshowed that there were also differences between the vibration frequency values(P <0.01), and decreased gradually with the periodontal attachment level toreduce the vibration frequency value.4. The vibration frequency of finite element models were1116.74Hz,989.1 Hz,728.6Hz,565.78Hz, respectively. The vibration frequency of finite elementanalysis were significantly greater than the clinical experimental results, butsimilar to the vibration frequency value after the elimination of additional mass.Conclusion:1. The vibration frequency of maxillary anterior teeth decreased with the lossof periodontal attachment.2. The additional mass of the accelerometer have a clear impact on thevibration frequency. Formula can used to eliminate the additional mass ofaccelerometer.3. The vibration frequency of finite element analysis were greater than theclinical experimental results, but similar to the vibration frequency value afterthe elimination of additional mass.4. Vibration frequency could be used as a parameter to indicate periodontalattachment loss.