Effect of gingiva on laser doppler pulpal blood flow measurements

Pulse oximetry in paediatric dentistry

Pulse oximetry is a technique used to measure the levels of blood oxygen saturation. Because this technique is regarded as non-invasive, easy to apply, and accurate technology, the number of possible applications in general dentistry practice has been gradually increasing. The aim of the present study was to summarise the contemporary research literature concerning the use of pulse oximetry in paediatric dentistry. We made a critical evaluation of the clinical applications of pulse oximetry and the advantages and disadvantages of this technique. Knowledge of innovative methods and techniques for treatment and diagnostics by paediatric dentists is a valuable advantage in dealing with the functional problems in attending dental patients. The expository analysis allows reviewing the succession of this diagnostic approach.

Efficacy of Laser Doppler Flowmetry, as a Diagnostic Tool in Assessing Pulp Vitality of Traumatised Teeth: A Split Mouth Clinical Study

Aim: This study aimed to evaluate the efficacy of laser Doppler flowmetry (LDF) in determining the changes in the pulpal blood flow (PBF) during post-traumatic period of the traumatised permanent teeth. Methods: 88 teeth of 44 patients (mean age 10.30 ± 2.38) were recruited according to the eligibility criteria and divided into two groups: test group (44 traumatised teeth) and control group (44 sound and healthy teeth). The measurement of PBF was performed, using a LDF monitor. Results: The analysis of the LDF outcomes in function of diagnosis indicated that the measurements of the traumatised teeth were significantly higher than those of non-traumatised teeth (p ˂ 0.05). Conclusions: LDF application provides dentists with fundamental benefits in terms of an early and precise investigation of PBF. In addition, LDF is a useful monitoring tool for revascularization of traumatised teeth and reliable objective diagnostic indicator of pulp vitality. Trial registration: ClinicalTrials.gov (Registration number: NCT04967456).

The Decisive Role of Laser Doppler Flowmetry for Pulp Preservation in Discolored Traumatized Teeth

Objective: It has been stated that blood pigments within discolored teeth may interfere with Laser Doppler Flowmetry (LDF) measurements. The aim of this study was to assess pulp vitality with LDF in a cohort of discolored traumatized teeth referred for endodontic treatment or where the referring dentist had doubts regarding maintained tooth vitality. Background: Discoloration of teeth is a common sequel of dental trauma. Still today, it is taken as an indicator for root canal treatment. Transient apical breakdown (TAB) is confused with apical periodontitis, although it is a sequel of dental trauma in young mature teeth and will result in revascularization and dissolution of the apical radiolucency. Methods: A total of 26 patients with 28 discolored teeth, belonging to a cohort of referred patients with traumatized teeth referred for root canal treatment and/or pulp vitality assessment were screened on color with photographs by three investigators, with traditional sensibility tests and with a Moor VMS II LDF meter. Results: The color of the intrinsically discolored teeth was grayish in 58% of teeth, blue 20%, pink/crimson 12%, and yellow 4%. Eighty-five percent were central maxillary incisors, 11% were mandibulary incisors. Thanks to LDF, 43% of the trauma cases in this small cohort with discoloration underwent root canal treatment instead of 70% with traditional sensibility tests as indicator. TAB was found in 11%. Conclusions: LDF was decisive in diagnosing vitality of discolored teeth and there was no negative impact of tooth discoloration on LDF measurements.

Pulp Vitality Testing with a Developed Universal Pulse Oximeter Probe Holder

Background and Objectives An accurate determination of the pulp status is relevant for a proper endodontic diagnosis. Objectives: The aim was to develop a universal pulse oximeter probe holder for measuring the oxygen saturation and to evaluate the use of pulse oximetry as a test for pulp vitality, by comparing the levels of oxygen saturation in the index finger and in the healthy dental pulp. Materials and Methods The universal holder was designed with software and printed with a 3D printer. The study was carried out on 128 healthy teeth. They were divided into eight groups according to tooth type. Ten root canal treated teeth served as a negative control group. For each patient, a pulse oximeter was first applied on the tooth followed by the index finger. The significance level (α) was set at 0.05. Results: The developed and manufactured universal pulse oximeter probe holder was suitable to measure the pulp vitality of all types of teeth. The handle allowed for holding the pulse oximeter on the tooth in parallel, firmly and securely. Significantly higher oxygen saturation was observed in the index finger (97.22%) compared to the dental pulp (93.17%) (p < 0.001). No correlation was observed between the maxillary teeth and index finger oxygen saturation values (r = 0.05, p = 0.72), whereas, between the mandibular teeth and index finger, a positive correlation was detected (r = 0.29, p = 0.02). There were no significant differences in the pulp oxygen saturation values between different teeth groups. Conclusion: The newly developed universal pulse oximeter probe holder is an effective device for pulp vitality testing.

Changes in pulp blood flow and pulp sensibility resulting from surgically assisted rapid maxillary expansion: A clinical study

INTRODUCTION

The aim of this work was to assess and compare changes in pulp blood flow (PBF) and pulp sensibility (PS) after surgically assisted rapid maxillary expansion (SARME) and rapid orthopedic maxillary expansion (OME).

METHODS

Ten patients requiring SARME and 10 requiring OME had the pulp status of their maxillary incisors and canines assessed with the use of laser Doppler flowmetry, electric pulp testing (EPT), and CO₂ snow. The SARME group was assessed at T1-S (before surgery), T2-S (after surgery, before expansion), T3-S (after surgery, at completion of expansion), and T4-S (3 months after surgery). The OME group was assessed at T1-O (before expansion), T2-O (after rapid expansion), and T3-O (3 months after expansion commencement). Relationships between PBF/PS and the procedures, assessment times, and tooth types were evaluated.

RESULTS

In the SARME group, surgery did not cause significant (P ≥0.05) reduction in PBF, maxillary expansion did cause significant (P ≤0.05) reduction in PBF, pretreatment PBF was reestablished by T4-S, and nonresponses to both EPT and CO₂ peaked at T2-S. In the OME group, rapid expansion caused significant (P ≤0.05) reduction in PBF, pretreatment PBF was reestablished by T3-O, and all teeth responded to at least 1 of EPT or CO₂ at each assessment time.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Within the study's limitations, it can be concluded that both SARME and OME induce reduction but not elimination of PBF to maxillary anterior teeth and therefore do not cause loss of pulp vitality; surgery for SARME does not significantly reduce PBF to maxillary anterior teeth, rather it is the process of maxillary expansion that significantly reduces PBF in SARME patients; and caution when using CO₂ and EPT tests alone to assess pulp status after SARME is warranted because the capacity for CO₂ or EPT to provide negative sensibility responses despite the presence of PBF was observed.

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.

A Clinical Study on the Effect of Injection Sites on Efficacy of Anesthesia and Pulpal Blood Flow in Carious Teeth

This randomized clinical trial evaluated the efficiency of maxillary infiltration anesthesia in carious teeth at two different injection sites and their impact on the laser Doppler recordings of pulpal blood flow (PBF) during a caries excavation procedure. The null hypothesis tested was that there are no differences in the efficiency of anesthesia and PBF reduction between maxillary infiltrations at the two injection sites. One hundred twenty patients were divided into three groups according to the degree of carious lesion of their maxillary left central incisors (moderate caries, deep caries, or no caries). Forty patients in each group randomly received infiltrations over the root apex of maxillary left central incisors (site X) or over the midpoint of the line connecting the root apexes of both maxillary left central and lateral incisors (site Y) using 0.9 mL 2% lidocaine with 1:100,000 adrenaline. Teeth were pulp tested at five-minute intervals after injection except for the period of cavity cutting, which was done 12 minutes after injection. The PBF changes after injection were monitored by laser Doppler flowmetry. The observation period in this study was 60 minutes. Success of anesthesia was defined as no or mild pain on cavity cutting by visual analog scale recordings. Deep caries group showed significantly higher baseline PBF ( p<0.05). All groups showed 100% success of anesthesia and similar duration time ( p>0.05). Subgroups that had the injection at site Y showed significantly less reduction of PBF ( p<0.05). Cavity-cutting procedures increased the amplitude of the PBF around the lowest value after injection. Independent of the cavity depth, carious anterior teeth anesthetized by infiltration further from the apex had significantly less reduction on the pulpal blood flow compared with teeth anesthetized by infiltration at the apex.

Changes in maxillary incisor dental pulp blood flow during intrusion by mini-implants

AIM

The aim of this clinical study was to identify changes in pulpal blood flow (PBF) in human central incisors resulting from short- and long-term intrusive orthodontic forces from mini-implants.

MATERIALS AND METHODS

A total of 40 sound upper central and lateral incisors in 20 patients scheduled for intrusion for orthodontic reasons were divided into two groups. From each group, 20 teeth were subjected to intrusive force from mini-implants (Group 1 = Light Force: 40 g; Group 2 = Heavy Force: 120 g), whereas the remaining 20 contralateral teeth were not subjected to forces from mini-implants and served as controls. Laser-Doppler flowmetry (LDF) measurements were recorded at baseline and at 3 days and 3 weeks following intrusion.

RESULTS

PBF decreased significantly at 3 days (Light Force Group: 7.72 ± 0.50; Heavy Force Group: 7.72 ± 0.52) and then increased towards baseline at 3 weeks (Light Force Group: 10.37 ± 0.58; Heavy Force Group: 10.31 ± 0.45) following intrusion.

CONCLUSIONS

In other words, despite slight regressive changes in pulpal tissue in the short-term, PBF improved after 3 weeks following intrusion by mini-implants, indicating that the changes observed in PBF is reversible, even following radical incisor intrusion.

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.

Improvement of the detection of human pulpal blood flow using a laser Doppler flowmeter modified for low flow velocity

OBJECTIVE

Human pulpal blood flow (PBF) signals as measured by laser Doppler flowmeter (LDF) decrease with age. Although this decrease is considered to be due in part to slow blood flow, information regarding this velocity in humans has been lacking. The aims of the present study were to estimate the blood flow velocity in human dental pulp and to evaluate the validity of LDF modified for the measurement of slow blood flow.

DESIGN

Mean blood flow velocities at the upper central incisor, gingiva, fingertip and forearm of 28 volunteers (mean age: 38.6 years old) were estimated using LDF with a frequency analyser. Blood flow signals at these measurement areas were recorded using two different LDFs: (a) one with a standard blood flow range; and (b) one modified for low blood flow velocity.

RESULTS

The frequency range of the Doppler shift measured at the teeth with an opaque rubber dam was the narrowest (median: 4.3kHz) among all of the measurement areas. The estimated mean blood flow velocity was the slowest at the teeth with a dam (median: 0.18mm/s). LDF for low blood flow velocity detected larger and clearer pulsatile blood flow signals from the teeth with dams than did standard LDF.

CONCLUSIONS

The present results indicate that the velocity of PBF in humans is very low and that LDF modified for the measurement of slow blood flow is appropriate for PBF measurement in humans.

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.

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.

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

OBJECTIVES

The aim was to determine the strength of signals derived from the dental pulp and those from the surrounding tissues in human teeth using the laser Doppler flowmetry (LDF).

METHODS

Twenty-six vital teeth (13 experimental and 13 controls) from 12 patients were used. Experimental teeth had root canal treatment in a single visit and their healthy antimeres were controls. Blood flow measurements were made before and after local anaesthesia, after root canal preparation, following root canal filling and coronal restoration.

RESULTS

Perfusion unit (PU) values recorded from empty pulp chamber were determined to be only 30% lower than the values recorded before anaesthesia from the experimental intact teeth. When the measurements in the group were compared with each other the values of variation in the both groups were not statistically significant. The variation between the groups when the measurement values before anaesthesia, 10min after anaesthesia and after coronal restoration were compared, it was not statistically significant (P>0.05). The variation between the groups after preparation and root canal filling in their values of measurements was important statistically (P<0.05). The measurement values of the study group were lower than that of the control group.

CONCLUSIONS

In pulpal, LDF a major portion of the signal comes from tissues other than pulp. Without taking precautions (such as rubber-dam application) in pulp blood flow measurements, the results may be inconsistent.