Use of in-fiber Bragg grating sensors to measure PDL strain in an ex-vivo swine model

Abstract

Although in-fiber Bragg grating (FBG) sensors have been used to measure strain within the PDL in a swine model, how fluid movement and collagen deformation contribute to these measurements remain unknown. The purpose of this study is to determine whether FBG sensors detect changes within the PDL of ex-vivo swine tooth-PDL-bone complex (TPBC) samples when manipulating fluid flow and fiber content. Being able to record strain will allow a better understanding of the biomechanics of viscoelastic load transfer from the tooth to the PDL that lead to orthodontic tooth movement. FBG sensors placed within the PDL of swine incisor teeth were used to measure strain resulting from an intrusive load applied by an MTS machine and compared between varying conditions: dry vs. saline (n=19) and saline vs. collagenase and fiberotomy (n=11). Saline samples resulted in greater strain values than collagenase-treated, whereas dry and saline did not statistically differ. The dry and collagenase-treated strain and force values were more consistent than the saline. There was also a downward trend in measured force values for the saline and collagenase-treated specimens that was not noticed in the dry sample. Further studies will lead to more precise and controlled tooth movement as we gain knowledge of the required forces needed to induce adequate strain on the PDL for remodeling. In conclusion, the FBG sensors were able to detect fluid and fibrous changes within the PDL environment, and both seem to be involved in determining strain in response to loading.