Pulpal Blood Flow Research Articles

Making sense of sensibility: part 1.

Thermal and electric pulp sensibility tests are commonly used by the majority of clinicians when diagnosing endodontic disease. These tests indirectly determine the state of pulpal health by assessing the response of the Aδ nerve fibres within the pulp-dentine complex. A positive response to sensibility testing indicates that the nerve fibres are functioning but does not give any quantitative information on nerve function, pulpal blood flow or histological status of the dental pulp. These tests have inherent limitations, including a reliance on a patient's subjective response to the test and the dentist's interpretation of the patient's response. This two-part series aims to help clinicians to reach an accurate endodontic diagnosis by providing an overview of how to undertake common pulpal sensibility tests correctly, how to interpret their results and understand their limitations. This section provides an overview of pulp testing, definitions of terminology relevant to pulp testing, the diagnostic uses of pulp testing and a summary of the diagnostic accuracy of different pulp tests.

Assesment of radiotherapy effects on the blood flow in gingiva and dental pulp - a laser Doppler flowmetry study

This study aims to determine and compare the dental pulp and gingival blood flow in patients referred for oropharyngeal radiotherapy (RT) at three different time points: before the start, immediately after, and six months following the completion of RT. The aim is also to evaluate the dependence of the pulp and gingival blood flow on the radiation dose. A prospective study included 10 patients referred for intensity-modulated RT (IMRT) in the oropharyngeal region, with at least one intact tooth surrounded by a healthy gingiva. The dose received by each selected tooth and adjacent gingiva was determined according to the map of treatment planning and computer systems. The blood flow measurements were performed using the laser Doppler flowmetry (LDF) method. Comparing vascular flows at three different time points, the median blood flow in the dental pulp showed no statistically significant difference (p=0.325), contrary to gingiva (p=0.011). Immediately after RT completion, the gingival flow significantly increased compared to its starting point (p=0.012). The pulp flow correlated negatively with the radiation dose, whereas a strong correlation was noted 6 months following the RT completion. RT caused a significant acute gingival blood flow increase, followed by a long-term (over six months) tendency to return to the starting levels. The dental pulp blood flow is differently affected by higher radiation doses (over 50Gy) in comparison to lower doses (below 50Gy). During RT planning, considering the possibility of protecting the teeth localized near the Gross Tumor Volume as a sensitive organ is recommended.

Differences Between Laser Doppler Flowmetry and Pulse Oximetry in Endodontics

An essential diagnostic step in the practice of dentistry is the evaluation of pulp vitality. In particular after traumatic accidents, the results of a pulp vitality test are critical for tracking the health of tooth pulp. The innervation is a factor in the classic pulp testing techniques like thermal and electrical, which frequently produce misleading positive and negative results. Pulp vitality suggests that there is a blood flow in the tissues. The most recent pulp testing tools, some of which are still in the research and development stage, locate the pulp's blood supply and are thought to be more precise and non-invasive. Pulse oximetry and laser Doppler flowmetry have recently been used in assessments of pulpal circulation. The fundamental tenet of pulse oximetry is that arterial blood alone exhibits pulsatile absorbance between the light source and the photo detector. Laser doppler flowmetry is a semi-quantitative recording of pulpal blood flow made possible by the non-invasive, painless electro optical technology. Even in the microvasculature's incredibly tiny blood arteries, blood flow can be measured. Pulse oximetry is helpful in impact injury situations where the blood supply is unharmed, but the nerve supply has been compromised. Widespread clinical use of smaller and less expensive commercial oximeters is now possible in a typical dental office. The disadvantages include the lack of differentiation in background absorption related to venous blood and tissue elements. LDF is helpful for early childhood where responses are unreliable, and because it is non-intrusive, it encourages patient tolerance and cooperation. However, for usage in a dental practice, it is regarded as being too costly of a technology. Additionally, blood pigments in a stained dental crown may obstruct the transmission of laser light. Both techniques provide an objective evaluation of the state of the pulpal blood circulation.

Pulp changes from rapid maxillary expansion: A systematic review.

This study aimed to systematically review the current evidence on the occurrence of pulp changes as side effects from orthopaedic rapid maxillary expansion (ORME) or surgically assisted rapid maxillary expansion (SARME). An electronic search was performed in eleven databases. The eligibility criteria included clinical studies assessing vitality, sensibility or dimensions of the pulp chamber of permanent teeth before and after ORME or SARME, without restrictions on publication year or language. The risk of bias was analysed with the NIH 'Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group' and the 'JBI for quasi-experimental studies' tool. The GRADE tool was used to assess the certainty of evidence. The initial search resulted in 1,197 records, from which only seven before-after studies were included. There was a change in the pulpal blood flow (PBF) of maxillary incisors and canines up to 5days after SARME, which gradually returned after 7days to 3months. After ORME, one study observed an increased PBF and one study observed a reduced PBF, which gradually returned after the end of expansion. Two studies observed that both ORME and SARME caused temporary changes in pulp sensibility. Three studies observed a significant reduction in the pulp chamber after ORME or SARME. The outcomes presented a very low certainty of evidence. Although limited, the evidence shows that ORME and SARME caused temporary changes in pulp vitality and sensibility, with the possibility of inducing a reduction in pulp chamber dimensions.

Effects of Local Anesthetics With Vasoconstrictors on Dental Pulp Blood Flow and Oxygen Tension.

The aim of this study was to investigate the changes in pulpal blood flow (PBF) and pulpal oxygen tension (PpulpO2) after injecting local anesthetics with vasoconstrictors. Under general anesthesia, male Japanese White rabbits were injected with 0.6 mL of 2% lidocaine with 1:80,000 epinephrine (LE) or 3% propitocaine (prilocaine) with 0.03 IU felypressin (PF) at the apical area of the lower incisor. Relative to baseline, PBF and PpulpO2 significantly decreased 5 minutes after LE or PF injection as compared with saline. The decrease in PBF was significantly lower in the LE group than in the PF group. Although the LE group had a larger decrease in PpulpO2 relative to baseline than the PF group did, that difference was not significant. PBF and PpulpO2 recovered to baseline faster in the PF group than in the LE group. The injection of local anesthetic solutions containing vasoconstrictors (LE or PF) transiently caused significant decreases in PBF that resulted in significant decreases in PpulpO2. The recovery of PpulpO2 was faster than PBF regardless of the vasoconstrictor used.

Vertically Polarized Laser Speckle Contrast Imaging to Monitor Blood Flow in Pulp

This research aimed to study a polarized laser speckle contrast imaging (LSCI) system to assess the pulp blood flow, where the ability of vertically polarized LSCI (vp-LSCI) and the non-polarized LSCI (np-LSCI) systems has been compared through space contrast algorithm and time contrast algorithm. The results showed that the vp-LSCI system could detect a wider contrast dynamic range in the pulp flow, approximately 1.5–2 times than that of the np-LSCI system. The time contrast algorithm detected small velocity changes of 0.03–0.07 mm/s, and its detectability index was 5–10 times than the space contrast algorithm. The vp-LSCI system combined with time contrast algorithm greatly improves the ability of laser speckle to detect pulp blood flow and can detect a wider range of blood flow velocity and smaller changes of blood flow. It indicated that our system may be a promising tool for clinical assessment of pulp blood flow.

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 effect of single buccal infiltration anesthesia of 4% articaine with either 1:100,000 or 1:200,000 epinephrine on pulpal blood flow and anesthesia of maxillary first molars and second premolars in humans.

The aim of this study was to determine the effect of single buccal infiltration of 4% articaine with either 1:100,000 (EP100) or 1:200,000 (EP200) epinephrine on pulpal blood flow (PBF), pulpal anesthesia and soft tissue anesthesia of maxillary first molars and second premolars in human subjects. Fifteen healthy volunteers with intact maxillary first molars and second premolars received an infiltration of 4% articaine with either EP100 or EP200 at buccal aspect of maxillary first molars. The PBF, pulpal anesthesia and soft tissue anesthesia were assessed with a laser Doppler flowmeter (LDF), an electric pulp tester (EPT) and Aesthesiometer II, respectively. Articaine (4%) with either EP100 or EP200 produced PBF reduction in maxillary first molars (injected teeth) by 68.09 and 69.83%, and produced PBF reduction in second premolars (adjacent teeth) by 76.81 and 75.02%, respectively at 15min post injection. Duration of PBF returned to baseline was 159.00 ± 21.06 (EP100) and 159.00 ± 31.97 (EP200) min in the molars, and 161.00 ± 20.02 (EP100) and 159.00 ± 25.86 (EP200) min in the premolars. The onset of pulpal anesthesia was 2.80 ± 1.26 (EP100) and 3.07 ± 1.28 (EP200) min in the molars, and 2.13 ± 0.52 (EP100) and 2.40 ± 0.83 (EP200) min in the premolars; the duration of pulpal anesthesia was 74.53 ± 24.16 (EP100) and 76.27 ± 34.03 (EP200) min in the molars, and 82.53 ± 31.03 (EP100) and 75.60 ± 37.17 (EP200) min in the premolars. Buccal tissue anesthesia was found in both teeth (100%), but palatal anesthesia was achieved by 13.33% in the premolars and 6.67% in the molars for each solution. Single buccal infiltration to maxillary first molar produced PBF reduction and successful pulpal anesthesia, evaluated by EPT, in both first molar and second premolar. This anesthetic technique also produced high success of buccal tissue anesthesia, but demonstrated very low success for palatal tissue anesthesia. Single buccal infiltration to maxillary first molar is potent enough for pulpal and buccal tissue anesthesia, except palatal tissue anesthesia, in both first molar and second premolar.

Prognostic markers of post-traumatic dental external root resorption in children-a pilot study.

External inflammatory root resorption (EIRR) is a frequent complication of traumatic dental injuries (TDI). The aim of this cohort study was to identify novel non-invasive markers of post-traumatic EIRR by assessing the changes in the pulp's blood flow and the composition of gingival sulcus fluid (GCF) in children after dental trauma. Thirty-two children were enrolled and assessed within 48h of a TDI to their permanent incisors and during an additional three visits over a 6-months follow up period. During each visit, a radiograph and laser Doppler flow (LDF) measurements of the pulp blood flow were performed on the injured tooth, and the GCF was sampled. The permanent first molar tooth of the same subject served as a control for the LDF measurements and the GCF sampling. Concentrations of IL-1α in the GCF were measured using enzyme-linked immunosorbent assays. Radiographs were used to confirm EIRR. EIRR occurred in fourteen (43.8%) teeth in 32 patients. The teeth with EIRR showed diminished LDF readings when compared with controls at all visits. The LDF readings of the injured teeth continued to decrease at follow up visits. In the EIRR group, levels of IL-1α in the GCF of teeth with EIRR were increased and significantly higher than those of the control teeth at the visit when EIRR was diagnosed. The IL-1α levels were significantly higher in the EIRR group when compared to the injured teeth of patients without EIRR at the last follow-up visit. The occurrence of EIRR after mechanical trauma of permanent teeth with complete root development is accompanied by a significant reduction in the blood flow of the tooth's pulp. It is accompanied by an increase in concentrations of IL-1α in the GCF of EIRR affected teeth. The results of this pilot study identified the use of IL-1α in GCF and LDF as non-invasive markers of EIRR.

Response to the Letter.

Response to the Letter.

Time-course of the effect of potassium oxalate in the treatment of hypersensitive dentine in man

ObjectiveInvestigate the cause of hypersensitive dentine (HD) by recording the time course of changes in dentine sensitivity, sensory threshold to electrical stimulation (ET) and pulpal blood flow (PBF) following tubular occlusion using in vitro and clinical experiments. DesignNineteen teeth with HD and 13 with normal dentine from 8 participants were evaluated, and the intensity of any pain produced by various stimuli was recorded at different times after oxalate treatment. The participants used a visual-analogue scale (VAS) to indicate the intensity of any pain. The ET and PBF were recorded at the same times. ResultsPreliminary in vitro experiments showed that oxalate treatment had no effect on the method used to record PBF, and blocked the treated tubules immediately after application. Considering teeth with HD, a decrease in the median VAS evoked by all forms of stimulation was observed at all post-treatment times, except immediately after treatment (p < 0.05), while the treatment produced no significant effect in teeth with normal dentine. No significant changes in ET or PBF was observed in any of the groups. ConclusionsThe effect of oxalate in relieving the symptoms of HD is not only due to a reduction in the intensity of stimulation of sensory receptors sensitive to fluid flow in the dentinal tubules, but also to a reduce in the sensitivity of the receptors that respond to dentine stimulation. There was no evidence that acute pulpitis or central sensitization to pain, which would be associated with changes in PBF or ET, contributes to HD.

Pulpal blood flow changes and pain scores related to using Superelastic 0.018-inch Nickel Titanium as the first orthodontic alignment archwire: a prospective clinical trial.

Background Optimal orthodontic force results in maximum rate of tooth movement without tissue damage. Even though starting orthodontic treatment with a thicker archwire may shorten treatment duration, the evidence on the effect of using 0.018-inch NiTi as the first alignment archwire on pulpal blood flow (PBF) status is still scarce.Objectives to record PBF changes and pain scores associated with using 0.018-inch NiTi as the first alignment archwire during fixed orthodontic treatment.Methodology Patients were selected from subjects attending postgraduate orthodontic teaching clinics at Jordan University of Science and Technology. In total, forty healthy patients who exhibited mild lower arch crowding were included. A split-mouth trial design was used. Each patient received two archwire sizes at one time joined in the midline by crimpable hook and applied in the lower arch. Patients were assigned into one of two groups based on archwire sizes used. Group 1: 0.014-inch and 0.018-inch NiTi (Six males, 14 females aged 19.4±1.33 years) and Group 2: 0.016-inch and 0.018-inch NiTi (Seven males, 13 females aged 19.6±1.45 years). The archwire size group was randomly allocated with a 1:1 allocation ratio. A Laser Doppler Flowmeter was used to measure PBF at different time intervals (T0-T5). Pain scores were recorded using a visual analogue scale (VAS). A repeated measures ANOVA and a post-hoc Bonferroni comparison tests were conducted to examine differences at the different time points before and during orthodontic alignment.Results For all studied archwire sizes, PBF decreased 20 minutes after their placement. Most PBF changes occurred within 24hours and continued to decrease until 72 hours after archwire placement where the maximum reduction was reached. Eventually, normal values were reverted within 1 month. PBF changes were similar between all alignment – groups.Conclusions Initial orthodontic alignment with 0.018-inch NiTi does not cause irreversible changes to pulpal vasculature or produces higher pain scores.

The state of microcirculation and identification of microcirculatory predictors of chronic pain in younger patients with functional disorders of the masticatory system affected by connective tissue dysplasia

Relevance. Occlusal splints, made for the patients with temporomandibular disorders (TMD), influence proprioceptive sensitivity, sensory characteristics of pain, parameters of microcirculation of the pulp and periodontium of the healthy teeth. Condition of the pulp and periodontium of the healthy teeth should be assessed in patients with TMD associated with connective tissue dysplasia (CTD).Materials and methods. The study examined 36 TMD patients aged 26.3 ± 1.3 лет (М ± m) with CTD (n = 20, main group) and without CTD (n = 16, control group); with natural teeth, without complaints of TMD, masticatory muscles and periodontal condition. Laser doppler flowmetry (LDF) helped to analyze blood flow parameters in the periodontium and pulp of the healthy teeth. Received results were statistically analyzed.Results. Wavelet analysis revealed different microcirculatory flowmotion: high-amplitude irregular type was in patients of the main group, low-amplitude regular type was in controls. In the main group, perfusion is supported by high values of flux and vasomotion, ergotropic sympathetic effects (controlled by catecholamines) prevail, myogenic tone is reduced, elevated microvascular tone reflects possible changes in rheologic blood properties, microcirculatory signs of pain syndrome and relatively elevated ischemic index in pulp microcirculation of healthy teeth.Conclusion. Sensory and regulatory mechanisms, reflected by the condition of periodontium and pulp blood flow, can be regarded as early signs of inflammation and chronic pain in the diagnosis of TMD in patients without complaints.

Using Laser-Doppler Flowmetry to Evaluate the Therapeutic Response in Dentin Hypersensitivity.

Dentin hypersensitivity (DH) is a common medical condition with underreported prevalence and it is difficult to quantify. This study aimed to investigate whether assessing dental pulp vascular micro-dynamics by laser-Doppler flowmetry (LDF) would be functional for therapeutic evaluation, in contrast to a verbal rating scale (VRS). A split-mouth single-blind randomized study was conducted on seven patients and a total of 36 teeth. Two DH therapeutic methods were employed: (i) fluoride gel; (ii) Nd:YAG radiation combined with fluoride gel. For each tooth, five consecutive LDF determinations of pulp blood flow were made (before and immediately after desensitizing treatment, then after 24 h, 7 days, and 1 month), and the VRS was applied each time. Spearman’s correlation was applied for concurrent validation. Two-way (treatment and patient) repeated measures ANOVA full factorial was applied, followed by Tukey’s post-hoc comparisons and Pillai’s trace multivariate statistic. While VRS scores had moderate reliability, LDF could objectively estimate treatment effects. Based on partial eta-squared values, treatment and patient characteristics were estimated to explain about 84% and 50% of the variability, respectively. In conclusion, LDF is an objective technique that can quantitatively assess DH evolution, and it is effective in reliably monitoring oral health therapeutic interventions.

A laboratory study to detect simulated pulpal blood flow in extracted human teeth using ultrasound Doppler flowmetry.

To develop a laboratory-based tooth model of simulated blood flow in teeth and evaluate it using ultrasound Doppler flowmetry (UDF). A laboratory-based tooth model for UDF was created based on a microfluidic experimental model proposed by Kim & Park (2016 a,b). Twenty-one maxillary or mandibular anterior human teeth within 1month of extraction were used. Four holes were made in each tooth to fit 1.6-mm diameter polytetrafluoroethylene (PTFE) tubes: at the apical foramen, palatal surface in the centre of the crown, palatal surface apical to the cementoenamel junction (CEJ) and the root centre. Fluid mimicking pulsating blood was pumped (pressure range: 0-200mbar, flow rate range: 0-80μLmin-1 ) into the apical foramen via the PTFE tubes, which exited the tooth through the palatal surface in the centre of the crown (control group), palatal surface below the CEJ (group 1) and the palatal surface at the mid-root level (group 2). An UDF transducer of 20MHz was placed at a 60° angle to the labial surface of tooth and was used to measure the fluid flow velocity (Vs, Vas, Vm, Vam, Vd, Vad and Vakd). The flow velocity of the different groups was compared using the Wilcoxon signed-rank test, with a 95% confidence level. UDF facilitated the detection of the simulated pulpal blood flow in the control group and group 1, but not in group 2. The mean and standard deviations of Vas, Vam and Vakd were 0.921±0.394, 0.479±0.208 and 0.396±0.220cms-1 , respectively, in the control group, and 0.865±0.368, 0.424±0.215 and 0.487±0.279cms-1 , respectively, in group 1. The pulpal blood flow values of the control group and group 1 were not significantly different (p>0.05). This laboratory study revealed that ultrasound Doppler flowmetry enabled the detection of simulated blood flow below the level of the CEJ but not at the mid-root level.

Transmitted-light plethysmography detects changes in human pulpal blood flow elicited by innocuous tooth cooling and foot heating

ObjectivesThe present study aimed firstly, to investigate whether pulpal circulatory changes elicited by innocuous tooth cooling and foot heating can be monitored with transmitted-light plethysmography (TLP), which detects pulpal blood volume changes, and secondly, to assess the effect of autonomic nervous control on TLP values. DesignThirty sound permanent maxillary incisors in 30 healthy volunteers (age: 25–35 years) were examined. The photodiode and 525-nm light-emitting diode of a prototype TLP system (J. Morita) were fixed onto the palatal and labial side, respectively, of each tooth with a custom-made acrylic cap. The subjects were stimulated for 10 min by cold (0 °C) water application to the experimental tooth or 30 min by foot heating with a footbath (43 °C). TLP and finger plethysmography were simultaneously recorded before (baseline), during and after stimulation. TLP values and autonomic nerve activity were statistically analyzed using a repeated measures one-way ANOVA followed by Tukey post-hoc test and partial correlation analysis. ResultsTLP values decreased significantly after both innocuous stimuli (P < 0.05), and returned to their baseline levels shortly after the removal of the stimuli. There was no significant serial correlation between the autonomic nervous activity and TLP values (P > 0.05). ConclusionTLP was able to monitor the pulpal circulatory changes evoked by innocuous stimuli. Systemic autonomic nervous control mechanisms were not associated with the pulpal circulatory changes, suggesting the involvement of other mechanisms, such as somatosensory-sympathetic nervous control.

Pulp blood flow and sensibility in patients with a history of dental trauma undergoing maxillary expansion.

To assess changes in pulp blood flow (PBF) and pulp sensibility (PS) in teeth of patients with a history of dental trauma undergoing maxillary expansion. Twenty-five patients requiring rapid maxillary expansion (RME) had the pulp status of their maxillary anterior teeth assessed using laser Doppler flowmetry, electric pulp testing, and thermal testing (CO2 snow). Each patient was tested at T1 (prior to expansion), T2 (2 weeks after rapid expansion), and T3 (3 months after expansion). Relationships between PBF, time interval, and history of trauma were evaluated using linear mixed modelling. Within the Trauma group, PBF was significantly lower (P ≤ .05) at T2 and T3 in comparison to T1 and significantly lower (P ≤ .05) at T2 in comparison to T3. In the Non-trauma group, PBF at T2 was significantly lower (P ≤ .05) than PBF at T1 and T3; however, no significant difference (P > .05) in PBF was observed when comparing PBF at T1 and T3. In both groups, PS was maintained in almost all teeth (>90%). RME in healthy teeth causes reduction of PBF before reestablishment of pretreatment values. RME in traumatized teeth causes reduction of PBF without PBF being reestablished to pretreatment levels. Teeth with a history of compromise may have reduced adaptive capacity under insults such as RME, which should be appreciated during the informed consent process.

A comparative study of initial changes in pulpal blood flow between conventional and self-ligating fixed orthodontic brackets during leveling and alignment stage.

To evaluate and compare the initial changes in pulpal blood flow (PBF) between conventional and self-ligating fixed orthodontic brackets during leveling and alignment stage using 0.016 × 0.022 NiTi as alignment archwire. Twenty-two patients (16 females and 6 males) aged 19.00 ± 2.53 years who presented with mild lower arch crowding were selected to participate in the study. A split mouth study design was applied for each patient. The intervention (self-ligating brackets) was randomly allocated to the right or left side of the patient using the permuted random block size of 2 with 1:1 allocation ratio. Two different fixed appliance brackets were used in the lower arch (self-ligating brackets on one side and conventional brackets on the other side of the same patients. Two alignment archwires; 0.016″ NiTi and 0.016 × 0.022″ NiTi were used in this study. PBF was measured for the lower right and left sides using laser Doppler flowmetry at different time intervals (20 min, 24 h, 72 h, 1 week, and 1 month) RESULTS: PBF started to decrease 20 min after insertion of both archwires using both types of brackets. Maximum decrease was reached after 72 h of archwire insertion. After 1 week of force application, PBF started to increase to restore its original values after 1 month. Differences between the 2 groups were not significant (P > 0.05). In both treatment groups, PBF reduced within 48 h. PBF started to increase after 1 week until it reached its original values after 1 month. Changes in PBF at the measured time intervals in the two groups were similar. The use of 0.016 × 0.022″ NiTi immediately after 0.016″ NiTi for alignment does not produce any damaging effect on the teeth.

The effect of inferior alveolar nerve block anesthesia of 4% articaine and epinephrine 1:100,000 on blood flow and anesthesia of human mandibular teeth

Background/purposeLocal anesthetics and anesthetic techniques affect the patterns of pulpal blood flow (PBF) and pulpal anesthesia in human teeth. This study aimed to determine PBF changes and pulpal anesthesia of intact mandibular first molars and canines after administration of 4% articaine with epinephrine 1:100,000 using inferior alveolar nerve block (IANB). Materials and methodsTen healthy subjects received IANB of 4% articaine with epinephrine 1:100,000. Laser Doppler flowmetry and electrical pulp testing were combined to assess PBF changes and pulpal anesthesia of intact mandibular first molars and canines. The data were analyzed using one-way repeated-measures analysis of variance and Student–Newman–Keuls test. ResultsIANB with 4% articaine and epinephrine 1:100,000 did not have any significant change in PBF for the first 20 min post injection in mandibular first molars, and for 45 min post injection in the canines (P > 0.05). However, a hyperemic response occurred during 25–60 min post injection in the molars, and between 60 and 75 min post injection in the canines (P < 0.05). Thereafter, the PBF in both teeth returned to the baseline. Onset of pulpal anesthesia was 8.60 ± 2.12 min in the molars, and 9 ± 1.94 min in the canines. Duration of pulpal anesthesia was 82.40 ± 41.56 min in the molars, and 84 ± 47.40 min in the canines. ConclusionIn case of successful IANB, 4% articaine and epinephrine 1:100,000 caused insignificant changes in PBF up to 30 min but a hyperemic response at later time points. Thereafter, the PBF returned to the baseline.

Linear and nonlinear analysis of dental pulp blood flow oscillations in ageing.

To investigate the effect of ageing on control mechanisms of pulpal microcirculation using wavelet analysis and to calculate linear and nonlinear parameters of blood flow oscillations, in a healthy general population. Pulpal blood flow (PBF) oscillations were recorded on right maxillary central incisors using laser Doppler Flowmeter (PeriFlux PF 5001, Perimed, Jarfalla, Sweden) on a group of 10 young participants (20-25years) and a group of 10 older adults (60-70years). In total, 20 recordings were obtained for at least 20min (one recording on one tooth per subject). Using wavelet spectral analysis, the amplitude and power were calculated as a linear and Hurst exponent as a nonlinear parameter of PBF oscillations. Differences between the two groups were assessed with the independent Student t-test. Mean PBF levels were significantly lower (P=0.024) in older adults than in young participants. Relative amplitudes and powers corresponding to the myogenic (P=0.046, P<0.001, respectively) and neurogenic activity (P=0.04, P=0.01, respectively) were significantly higher, whereas values corresponding to the endothelial function (P=0.04, P=0.01, respectively) were significantly lower in older adults than in young participants. Hurst exponents of the total spectrum, myogenic and endothelial component (P<0.001, P=0.02, P<0.001, respectively) of PBF oscillations were significantly lower in older adults in comparison to young participants. At the level of pulpal microcirculation, ageing was associated with altered blood flow levels, the contribution of different control mechanisms to blood flow oscillations as well as the interaction of vascular smooth muscle and endothelium. Described changes of pulpal haemodynamics contribute to a better understanding of physiological behaviour and decreased adaptability of aged dental pulp to pathological stimuli.