@inproceedings{SchulzPutzgerNiklasetal., author = {Schulz, Irene and Putzger, J{\"u}rgen and Niklas, Andreas and Brandt, M. and J{\"a}ger, Andreas and Hardt, A. and Kn{\"o}rzer, S. and Hiller, Karl-Anton and L{\"o}ffler, S. and Schmalz, Gottfried and Danilov, Sergey N. and Giglberger, Stephan and Hirmer, Marion and Ganichev, Sergey D. and Monkman, Gareth J.}, title = {PPG signal acquisition and analysis on in vitro tooth model for dental pulp vitality assessmen}, series = {2nd Applied Research Conference 2012 (ARC 2012), 25./26. June 2012, Nuremberg}, booktitle = {2nd Applied Research Conference 2012 (ARC 2012), 25./26. June 2012, Nuremberg}, publisher = {Shaker-Verlag}, address = {Aachen}, organization = {ARC}, pages = {142 -- 146}, language = {en} } @article{KnoerzerHillerBrandtetal., author = {Kn{\"o}rzer, S. and Hiller, K-A and Brandt, M. and Niklas, Andreas and Putzger, J{\"u}rgen and Monkman, Gareth J. and Danilov, Sergey N. and Ganichev, Sergey D. and Schulz, Irene and Schmalz, Gottfried}, title = {Detection of pulsed blood flow through a molar pulp chamber and surrounding tissue in vitro}, series = {Journal of Clinical Oral Investigations}, volume = {23}, journal = {Journal of Clinical Oral Investigations}, number = {3}, publisher = {Springer Nature}, doi = {10.1007/s00784-018-2530-y}, pages = {1121 -- 1132}, abstract = {OBJECTIVES Due to severe limitations of dental pulp sensitivity tests, the direct recording of pulsed blood flow, using photoplethysmography (PPG), has been proposed. In vivo evaluation is methodologically difficult and in vitro models have hitherto been adversely influenced by shortcomings in emulating the in vivo situation. Consequently, the aim of this study was to test an improved data acquisition system and to use this configuration for recording pulsed blood in a new model. MATERIALS AND METHODS We introduced a PPG signal detection system by recording signals under different blood flow conditions at two wavelengths (625 and 940 nm). Pulsed blood flow signals were measured using an in vitro model, containing a molar with a glass pulp and a resin socket, which closely resembled in vivo conditions with regard to volumetric blood flow, pulp anatomy, and surrounding tissue. RESULTS The detection system showed improved signal strength without stronger blanketing of noise. On the tooth surface, it was possible to detect signals emanating from pulsed blood flow from the glass pulp and from surrounding tissue at 625 nm. At 940 nm, pulp derived signals were recorded, without interference signals from surrounding tissue. CONCLUSION The PPG-based method has the potential to detect pulsed blood flow in small volumes in the pulp and (at 625 nm) also in adjacent tissues. CLINICAL RELEVANCE The results show the need for clear differentiation of the spatial origins of blood flow signals of any vitality test method to be applied to teeth.}, language = {en} }