Herman Roeykens

Reliability of laser Doppler flowmetry in a 2-probe assessment of pulpal blood flow

OBJECTIVE The reliability of using 2 probes with laser Doppler signals when adjacent teeth are being measured simultaneously to determine pulpal blood flow is unknown. The purpose of this study was to determine whether 2 probes are more reliable than 1 in a single-tool assessment. STUDY DESIGN Tooth pulp vitality was studied in 19 adults through use of laser Doppler flowmetry tests. In each subject, testing was carried out on 2 successive occasions with 2 probes positioned on the maxillary central incisors. RESULTS Significant mean differences of 31% for blood flux and 96% for concentration were found between the 2 probes, although they shared equal coefficients of variation. The reproducibility for each probe was found to be consistent, and the probes were highly correlated with each other. Flux and concentration, however, were not systematically correlated. CONCLUSIONS Simultaneous measurements with 2 probes were clearly more reliable. The necessity for a calibration control was evident.

The use of laser Doppler flowmetry in paediatric dentistry

BACKGROUND: An early determination of pulpal vitality is crucial with respect to a correct differential diagnosis of revascularisation or necrosis and its treatment. REVIEW: Sensibility tests (cold, heat, electrical pulp test) in combination with radiographs are commonly promoted. However these tests are arbitrary, based on sensations and therefore not always reliable. In such situations registration of pulpal blood flow will be advantageous. The most studied and well documented method for registration of blood circulation is laser Doppler flowmetry (LDF) which is typified as a non-invasive technique with direct and objective registrations. In this article blood flow, LDF and its characteristics, the advantages and disadvantages of the methods and the latest developments regarding LDF is described. CONCLUSION: Despite there being a low implementation of LDF in dentistry to date, this should become one of the basic techniques for clinical use in paediatric dentistry.

Laser Doppler Flowmetry

An early determination of pulpal vitality is crucial with respect to a correct differential diagnosis of revascularisation or necrosis and its treatment. The use of sensibility tests (cold, heat, electric pulp test) in combination with X-ray is commonly promoted. However, these tests are arbitrary, based on sensations, and therefore not always reliable. In such situation, registration of pulpal blood flow will be more than an added value. The most studied and well-documented method for registration of pulpal blood flow is laser Doppler flowmetry (LDF), a non-invasive technique with direct and objective registrations. In this chapter, we describe pulpal blood flow, LDF and its characteristics, this method’s advantages and disadvantages and recent developments regarding LDF. Despite a low implementation of LDF in dentistry, this technique has proven to be an indisputable, basic asset of a dental clinic.

Diurnal variations and pulpal status: is there a need for FFT besides LDF?

The aim of this article was to investigate the use of laser Doppler flowmetry (LDF) combined with a fast Fourier transformation (FFT). LDF data in relation to three different scenarios were evaluated: (a) LDF records of a right central upper incisor of one patient were used for FFT analysis. These records were obtained by means of 30 pre-manufactured splints, handled by dentists without any experience in LDF recording. (b) Diurnal variations in one patient were analysed with LDF and FFT using 11 splints by one and same experienced investigator at four specific moments of the day. (c) Pulpal status was analysed using 17 splints. Eleven for a patient, standing as case model and six splints for six other patients. In this specific group, each patient had one vital and one non-vital central maxillary incisor and was analysed separately by LDF and FFT. The data of assessment (b) showed diurnal variations on LDF values of almost 80%, indicating that LDF registration is best performed in the same time period of the day. Data verification with FFT confirmed the findings without FFT of assessment (a) and (b). In assessment, (c) FFT demonstrated a clear distinction between a vital and a non-vital pulp for those cases with one vital tooth and one root canal treated tooth. In those cases with one vital incisor and the other traumatised, FFT was undeterminated. Considered that FFT was obtained after LDF recording and remained undeterminated for a decision in cases with decreasing pulpal blood flow in time, the added value of FFT in pulpal traumatology was minimal.