两类传感器对种植体共振频率测量值影响的三维有限元研究

研究背景：共振频率法被认为是目前相对理想的测量种植体稳定性的方法。共振频率仪的测量传感器分为L型传感器和无线式铝杆传感器两类,然而,目前种植领域尚不清楚这两类传感器所测量的种植体共振频率值有何异同。目的：采用三维有限元法研究在不同骨质类型和不同种植体长度情况下,L型传感器和铝杆传感器两种设计对种植体共振频率测量值的影响。方法：（1）建立种植体-传感器-下颌磨牙区骨块三维有限元模型（ANSYS5.6软件）。种植体尺寸：直径固定为4.0mm,长度分4个等级：8.0mm、10.0mm、12.0mm和14.0mm;传感器分为两类：L型（高度22.0mm）和铝杆型（高度11.5mm）;模拟了3种骨质类型,即D2、D3和D4骨质。（2）在本质上,种植体一阶弯曲振动模态下的固有频率与共振频率仪所测量的共振频率相同,因此本研究直接采用有限元软件计算不同参数条件下种植体-骨块复合体的一阶固有频率。结果：（1）L型传感器组种植体的频率值在3763～4464Hz之间（平均4235Hz）,而铝杆模型种植体的频率值在9192～10002Hz之间（平均9708Hz）。（2）骨质由D4变为D2时,L型传感器组种植体的频率值增加百分比在12.7～16.7%之间（平均14.9%）,铝杆传感器组的增加百分比在7.4～8.5%之间（平均7.9%）。（3）对于L型传感器组而言,长度增加其频率值逐渐增加,14.0mm与8.0mm相比,频率值平均增幅为3.2%,对于铝杆传感器而言,D3骨质模型的频率值随长度增加而增加,在D4和D2骨质条件下,频率值呈先升后降（变化幅度较小）。（4）在D3骨质情况下,L型传感器测量值和铝杆传感器测量值之间存在线性相关,具有显著性（Pearson相关系数r=0.996,P=0.004）;在D4骨质情况下,L型传感器测量值和铝杆传感器测量值之间存在负相关关系,但是没有统计意义（r=-0.846,P〉0.05）;在D2骨质情况下,两组数值存在正相关关系,但同样没有统计意义（r=0.736,P〉0.05）。结论：在相同骨质类型、相同种植体尺寸条件下,L型传感器模型的频率值远小于铝杆传感器模型的频率值;L型传感器反映骨质变化的灵敏度高于铝杆传感器;在D3骨质条件下,两种传感器均能反映出测量值随长度增加而增加这一趋势

Effects of transducer types on natural frequency values of dental implants

Objectives：To caculate the effects of transducer types on natural frequency （NF） values of dental implants by 3-D finite element analysis.Methods：The L-shaped transducer and the aluminum peg transducer were modelled and their effects on NF values of dental implants were analyzed.Results：In general,NF values of implants connected with the L-shaped transducer had a range of from 3763 to 4464 Hz,which was much less than the range of from 9192 to 10002 Hz generated in implants connected with the aluminum peg transducer.When bone quality increased from D4 to D2,NF values of the L-shaped transducer models went to higher levels with increasing rates ranging from 12.7 to 16.7% （mean： 14.9%）,however NF values of the aluminum peg transducer models increased by a range of from 7.4 to 8.5% （mean：7.9%）.In the L-shaped transducer models,increasing implant length resulted in higher NF values,with a mean increasing rate of 3.2%.In the aluminum peg transducer models,increasing implant length brought about higher NF values only when bone quality was D3.And in D3 bone quality models,a linear correlation was found between NF values of the two transducers models （r = 0.996,P=0.004）.Conclusion：NF values of the L-shaped transducer models were much less than those of the aluminum peg transducer models.The L-shaped transducer seems to be more sensitive to bone quality changes than the aluminum peg transducer.Only in D3 bone quality models,the two transducers measure smilar varying trends of implant NF values.