The sources of laser Doppler blood-flow signals recorded from vital and root canal treated teeth

A Diagnostic Insight of Dental Pulp Testing Methods in Pediatric Dentistry

The accurate diagnosis of pulpal pathology in pediatric dentistry is essential for the success of vital pulp therapy. Pulp testing is often a challenging task due to understanding and cooperation issues of pediatric patients, as well as the particularities of pulpal physiology encountered in primary and immature permanent teeth. Sensibility tests, although still widely used by dental practitioners, are no longer recommended by pediatric specialists mainly due to their subjective nature. Vitality pulp tests have gained popularity in the last decade in light of some encouraging results of clinical studies. However, their use is not a routine practice yet. This paper is a literature review aimed to guide dental practitioners towards selecting the appropriate pulp testing method for their pediatric cases. It provides an overview on a multitude of pulp testing methods and an update in recommendations for primary and immature permanent teeth.

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.

Pulp and periradicular testing

Pulp and periradicular testing is crucial to the initial trauma evaluation and to subsequent monitoring of the traumatized teeth and supporting structures. An accurate diagnosis serves as the basis for therapeutic intervention and helps to ensure that destruction of the dental structures will be minimized and function will be regained. The purpose of this review is to present the current best evidence for accurate diagnostic testing of the pulp and periapex of traumatized teeth. Five databases were searched for literature pertaining to pulpal testing and trauma. Widely recognized textbooks were also consulted. Currently used pulp vitality testing is constrained by its subjective character and by the fact that it is a measure of neuronal status and not true pulpal viability. Tests that measure tissue perfusion more accurately reflect pulpal vitality, but they are not available commercially. This review discusses the specificity, sensitivity, and accuracy of commonly used tests, with emphasis on the applicability of certain tests to specific patient presentations in trauma. Factors that influence test selection are discussed, and specific recommendations are made on the basis of best evidence. Although differences exist between the various studies as to the accuracy of commonly used pulpal and periradicular tests, most of these have acceptable predictive value. Pulpal and periradicular tests in the trauma patient should be used in conjunction with clinical and radiographic observations to arrive at a diagnosis and treatment plan.

Pulpal blood flow measurement with ultrasound Doppler imaging

INTRODUCTION

This study compared the difference in pulpal blood flow between vital and root-filled teeth by using ultrasound Doppler imaging.

METHODS

To compare the difference in pulpal blood flow between vital and root-filled teeth, 11 patients (mean age, 32.06 years; 3 male, 8 female) who had undergone root canal treatment on the anterior tooth of the maxilla or mandible and had a vital contralateral tooth were examined. Pulpal blood flow measurements were performed on the vital and root canal-treated teeth by using ultrasound Doppler imaging. The parameters examined were the maximum linear velocity (Vas), average linear velocity (Vam), minimum linear velocity (Vakd), pulsation index (PI), and circulation resistance (RI), which are indicators of the pulpal blood flow. The differences between the vital and root-filled teeth were examined by using a paired t test at the 95% confidence interval.

RESULTS

There were significant differences in the Vas, Vam, Vakd, and RI between the vital and root-filled teeth (P<.05). With the root-filled teeth, ultrasound Doppler imaging revealed a linear and nonpulsed waveform, whereas the vital teeth showed a pulsed waveform that is characteristic of an arteriole.

CONCLUSIONS

Ultrasound Doppler imaging can detect pulpal blood flow in vital tooth through indicators such as Vas, Vam, Vakd, PI, and RI.

Dental pulp testing: a review

Dental pulp testing is a useful and essential diagnostic aid in endodontics. Pulp sensibility tests include thermal and electric tests, which extrapolate pulp health from sensory response. Whilst pulp sensibility tests are the most commonly used in clinical practice, they are not without limitations and shortcomings. Pulp vitality tests attempt to examine the presence of pulp blood flow, as this is viewed as a better measure of true health than sensibility. Laser Doppler flowmetry and pulse oximetry are examples of vitality tests. Whilst the prospect is promising, there are still many practical issues that need to be addressed before vitality tests can replace sensibility tests as the standard clinical pulp diagnostic test. With all pulp tests, the results need to be carefully interpreted and closely scrutinised as false results can lead to misdiagnosis which can then lead to incorrect, inappropriate, or unnecessary treatment.

Evaluation of the ability of laser Doppler flowmetry for the assessment of pulp vitality in general dental practice

OBJECTIVES

In this study we investigated pulpal blood flow (PBF) values and moving blood cell velocity (MBCV) curves recorded by laser Doppler flowmetry (LDF) for pulpal vitality diagnosis in general dental practice and to compare MBCV curves to standard diagnostic tests in traumatology.

STUDY DESIGN

LDF tests performed with the PeriFlux System 5000 were applied to vital and nonvital (endodontic treatment) teeth of healthy students (n = 52) and on 24 luxated teeth of patients.

RESULTS

The PBF values were not reproducible and no statistically significant differences were observed between vital and nonvital teeth. MBCV curves in contrast could distinguish between the 2 tooth types. Tests on luxated teeth showed that while 62.5% of MBCV curves correlated with conventional vitality tests, only 12.5% of MBCV curves could help in vital diagnosis.

CONCLUSION

When applied to luxated teeth, the MBCV curve appeared to be accurate when the standard vitality tests indicated a nonvital diagnosis.

The lamp effect of laser Doppler flowmetry on teeth

The aim of this study is to analyse the intra and extracoronal scattering of laser light. Twelve vital teeth from 12 volunteer individuals (aged 22-29 years) were used. The camera removing the charge coupled device's infrared cut filter was used for imaging the laser Doppler flowmetry light during pulpal blood flow measurement. When the obtained photos were analysed, it was seen that the laser beam caused the tooth to shine like a lamp and it also illuminated the tissues inside the mouth (tongue, lips, adjacent teeth, etc.). As a result, it was shown that when the necessary cautions were not taken, the laser could scatter all around the tissues surrounding the tooth. Because of the conductive characteristic of the fibre and the optical characteristics of the tooth, we think that the beam is inevitably scattered onto the tissues outside the pulp and together with the isolation of the gingiva, crown should be isolated, as well.

Penetration depth of laser Doppler flowmetry beam in teeth

OBJECTIVE

The aim of this study was to determine the penetration depth of laser light in teeth for contact and noncontact probe tip.

STUDY DESIGN

Fifty-one freshly extracted human mature maxillary and mandibular single rooted teeth were selected for the study. A laser Doppler flowmeter was used as a laser source. A digital camera was used to take pictures (with "night shot" mode in total darkness). When probe tip was in contact and when it was 1 mm away from the tooth, the depths of the areas illuminated in high and low density were measured.

RESULTS

In contact probe, root was illuminated to 4.28 +/- 0.14 mm depth with high density and 13.27 +/- 0.27 mm depth with low density. In noncontact probe, 4.36 +/- 0.16 mm with high density and 13.28 +/- 0.30 mm with low density of illumination were seen on the root. Between contact and noncontact probe situations the difference was not statistically significant in the depth of illumination. On the other hand, in both groups the difference between areas illuminated in high and low density was statistically significant (P < .05).

CONCLUSION

Contact or noncontact of the probe on tooth surface did not show any significant difference in light penetration. Besides, we think that, for the present, it is impossible to eliminate the contamination from periodontal tissues completely even if the necessary precautions (periodontal paste etc.) are taken.