Advertisement

Clinical Oral Investigations

, Volume 18, Issue 5, pp 1401–1409 | Cite as

In vitro optical detection of simulated blood pulse in a human tooth pulp model

  • A. Niklas
  • K.-A. Hiller
  • A. Jaeger
  • M. Brandt
  • J. Putzger
  • C. Ermer
  • I. Schulz
  • G. Monkman
  • S. Giglberger
  • M. Hirmer
  • S. Danilov
  • S. Ganichev
  • G. SchmalzEmail author
Original Article

Abstract

Objective

Noninvasive optical methods such as photoplethysmography, established for blood pulse detection in organs, have been proposed for vitality testing of human dental pulp. However, no information is available on the mechanism of action in a closed pulp chamber and on the impairing influence of other than pulpal blood flow sources. Therefore, the aim of the present in vitro study was to develop a device for the optical detection of pulpal blood pulse and to investigate the influence of different parameters (including gingival blood flow [GBF] simulation) on the derived signals.

Materials and methods

Air, Millipore water, human erythrocyte suspensions (HES), non-particulate hemoglobin suspension (NPHS), and lysed hemoglobin suspension (LHES) were pulsed through a flexible (silicone) or a rigid (glass) tube placed within an extracted human molar in a tooth–gingiva model. HES was additionally pulsed through a rigid tube around the tooth, simulating GBF alone or combined with the flow through the tooth by two separate peristaltic pumps. Light from high-power light-emitting diodes (625 nm (red) and 940 nm (infrared [IR]); Golden Dragon, Osram, Germany) was introduced to the coronal/buccal part of the tooth, and the signal amplitude [∆U, in volts] of transmitted light was detected by a sensor at the opposite side of the tooth. Signal processing was carried out by means of a newly developed blood pulse detector. Finally, experiments were repeated with the application of rubber dam (blue, purple, pink, and black), aluminum foil, and black antistatic plastic foil. Nonparametric statistical analysis was applied (n = 5; α = 0.05).

Results

Signals were obtained for HES and LHES, but not with air, Millipore water, or NPHS. Using a flexible tube, signals for HES were higher for IR compared to red light, whereas for the rigid tube, the signals were significantly higher for red light than for IR. In general, significantly less signal amplitude was recorded for HES with the rigid glass tube than with the flexible tube, but it was still enough to be detected. ∆U from gingiva compared to tooth was significantly lower for red light and higher for IR. Shielding the gingiva was effective for 940 nm light and negligible for 625 nm light.

Conclusions

Pulpal blood pulse can be optically detected in a rigid environment such as a pulp chamber, but GBF may interfere with the signal and the shielding effect of the rubber dam depends on the light wavelength used.

Clinical relevance

The optically based recording of blood pulse may be a suitable method for pulp vitality testing, if improvements in the differentiation between different sources of blood pulse are possible.

Keywords

Dental pulp Vitality Blood flow Laser Doppler flowmetry Photoplethysmography Red light Infrared light Transmission Spectrum 

Notes

Acknowledgments

Support by the DFG (projects GA-501/10, SCHM 386/3, and MO 2196/1), the Linkage Grant of IB of BMBF at DLR and Applications Center “Miniaturisierte Sensorik” (SappZ) of the Bavarian Government, is gratefully acknowledged.

Conflict of interest

The authors declare that they have no conflict of interest.

References

  1. 1.
    Seltzer S, Bender IB, Nazimov H (1965) Differential diagnosis of pulp conditions. Oral Surg Oral Med Oral Pathol 19:383–391PubMedCrossRefGoogle Scholar
  2. 2.
    Mullaney TP, Howell RM, Petrich JD (1970) Resistance of nerve fibers to pulpal necrosis. Oral Surg Oral Med Oral Pathol 30:690–693PubMedCrossRefGoogle Scholar
  3. 3.
    Bhaskar SN, Rappaport HM (1973) Dental vitality tests and pulp status. J Am Dent Assoc 86:409–411PubMedGoogle Scholar
  4. 4.
    Daley J, Boyd E, Cooper J, O′Driscoll P (1988) Optical assessment of dental pulp vitality. J Biomed Eng 10:146–148PubMedCrossRefGoogle Scholar
  5. 5.
    Yan H, Gao W, Zhang F, Li Z, Chen X, Fan C (2012) A comparative study of finger pulp reconstruction using arterialised venous sensate flap and insensate flap from forearm. J Plast Reconstr Aesthet Surg 65:1220–1226PubMedCrossRefGoogle Scholar
  6. 6.
    Gazelius B, Olgart L, Edwall B, Edwall L (1986) Non-invasive recording of blood flow in human dental pulp. Endod Dent Traumatol 2:219–221PubMedCrossRefGoogle Scholar
  7. 7.
    Diaz-Arnold AM, Wilcox LR, Arnold MA (1994) Optical detection of pulpal blood. J Endod 20:164–168PubMedCrossRefGoogle Scholar
  8. 8.
    Schnettler JM, Wallace JA (1991) Pulse oximetry as a diagnostic tool of pulpal vitality. J Endod 17:488–490PubMedCrossRefGoogle Scholar
  9. 9.
    Jhanji S, Lee C, Watson D, Hinds C, Pearse RM (2009) Microvascular flow and tissue oxygenation after major abdominal surgery: association with post-operative complications. Intensive Care Med 35:671–677PubMedCrossRefGoogle Scholar
  10. 10.
    Pitt Ford T, Patel S (2004) Technical equipment for assessment of dental pulp status. Endodontic Topics 7(1):2–13Google Scholar
  11. 11.
    Raab WH-M (1989) Die Laser-Doppler-Flußmessung: Untersuchungen zur Mikrozirkulation der Zahnpulpa. Dtsch Zahnärztl Z 44:198–200PubMedGoogle Scholar
  12. 12.
    Simonovich M, Barbiro-Michaely E, Mayevsky A (2008) Real-time monitoring of mitochondrial NADH and microcirculatory blood flow in the spinal cord. Spine 33:2495–2502PubMedCrossRefGoogle Scholar
  13. 13.
    Polat S, Er K, Polat NT (2005) The lamp effect of laser Doppler flowmetry on teeth. J Oral Rehabil 32:844–848PubMedCrossRefGoogle Scholar
  14. 14.
    Akpinar KE, Er K, Polat S, Polat NT (2004) Effect of gingiva on laser Doppler pulpal blood flow measurements. J Endod 30:138–140PubMedCrossRefGoogle Scholar
  15. 15.
    Musselwhite JM, Klitzman B, Maixner W, Burkes EJ Jr (1997) Laser Doppler flowmetry: a clinical test of pulpal vitality. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 84:411–419PubMedCrossRefGoogle Scholar
  16. 16.
    Polat S, Er K, Akpinar KE, Polat NT (2004) The sources of laser Doppler blood-flow signals recorded from vital and root canal treated teeth. Arch Oral Biol 49:53–57PubMedCrossRefGoogle Scholar
  17. 17.
    Hartmann A, Azerad J, Boucher Y (1996) Environmental effects on laser Doppler pulpal blood-flow measurements in man. Arch Oral Biol 41:333–339PubMedCrossRefGoogle Scholar
  18. 18.
    Ingolfsson AR, Tronstad L, Hersh EV, Riva CE (1994) Efficacy of laser Doppler flowmetry in determining pulp vitality of human teeth. Endod Dent Traumatol 10:83–87PubMedCrossRefGoogle Scholar
  19. 19.
    Polat S, Er K, Polat NT (2005) Penetration depth of laser Doppler flowmetry beam in teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 100:125–129PubMedCrossRefGoogle Scholar
  20. 20.
    Yoon MJ, Kim E, Lee SJ, Bae YM, Kim S, Park SH (2010) Pulpal blood flow measurement with ultrasound Doppler imaging. J Endod 36:419–422PubMedCrossRefGoogle Scholar
  21. 21.
    Shelley KH (2007) Photoplethysmography: beyond the calculation of arterial oxygen saturation and heart rate. Anesth Analg 105:S31–S36 (tables of contents)Google Scholar
  22. 22.
    Alexander CM, Teller LE, Gross JB (1989) Principles of pulse oximetry: theoretical and practical considerations. Anesth Analg 68:368–376PubMedCrossRefGoogle Scholar
  23. 23.
    Hirmer M, Danilov S, Giglberger S, Putzger J, Niklas A, Jäger A et al (2012) Spectroscopic study of human teeth and blood from visible to terahertz frequencies for clinical diagnosis of dental pulp vitality. J Infrared Milli Terahz Waves 33:366–375Google Scholar
  24. 24.
    Niklas A (2010) In vitro Blutflussmessungen am Zahn-Pulpamodell. Südwestdeutscher Verlag für Hochschulschriften. ISBN 978-3-8381-2134-5Google Scholar
  25. 25.
    Noblett WC, Wilcox LR, Scamman F, Johnson WT, Diaz-Arnold A (1996) Detection of pulpal circulation in vitro by pulse oximetry. J Endod 22:1–5PubMedCrossRefGoogle Scholar
  26. 26.
    Kim S (1985) Microcirculation of the dental pulp in health and disease. J Endod 11:465–471PubMedCrossRefGoogle Scholar
  27. 27.
    Marin PD, Bartold PM, Heithersay GS (1997) Tooth discoloration by blood: an in vitro histochemical study. Endod Dent Traumatol 13:132–138PubMedCrossRefGoogle Scholar
  28. 28.
    Tonder KJ, Naess G (1979) Microvascular pressure in the dental pulp and gingiva in cats. Acta Odontol Scand 37:161–168PubMedCrossRefGoogle Scholar
  29. 29.
    Siemens Semiconductor Group (1997) PIN photodiode with very short switching time—SFH229Google Scholar
  30. 30.
    Enejder AM, Swartling J, Aruna P, Andersson-Engels S (2003) Influence of cell shape and aggregate formation on the optical properties of flowing whole blood. Appl Opt 42:1384–1394PubMedCrossRefGoogle Scholar
  31. 31.
    Lindberg LG, Oberg PA (1993) Optical properties of blood in motion. Opt Eng 32:253–257CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • A. Niklas
    • 1
  • K.-A. Hiller
    • 1
  • A. Jaeger
    • 1
  • M. Brandt
    • 1
  • J. Putzger
    • 2
  • C. Ermer
    • 2
  • I. Schulz
    • 3
  • G. Monkman
    • 3
  • S. Giglberger
    • 2
  • M. Hirmer
    • 2
  • S. Danilov
    • 2
  • S. Ganichev
    • 2
  • G. Schmalz
    • 1
    • 4
    Email author
  1. 1.Medical Faculty Dental SchoolUniversity of RegensburgRegensburgGermany
  2. 2.Department of PhysicsUniversity of RegensburgRegensburgGermany
  3. 3.Mechatronics Research UnitUniversity of Applied Sciences RegensburgRegensburgGermany
  4. 4.Department of Operative Dentistry and PeriodontologyUniversity of RegensburgRegensburgGermany

Personalised recommendations