Pulpal blood flow recorded from human premolar teeth with a laser Doppler flow meter using either red or infrared light

Bone Quality Assessment of Dental Implant Recipient Sites

The term bone quality is not clearly defined and depends on many factors, such as bone density, bone vascularity, bone metabolism and other factors that may affect implant outcome. The assessment of bone volume and bone density is most common in planning the treatment of dental implants. Bone quality is an important predictor of primary implant stability, which influences the future implant osseointegration. Numerous classifications have been described for the evaluation of bone density. The most commonly used has been the one proposed by Lekholmu and Zarb. For the objective evaluation of bone density, conventional computed tomography (CT) or Cone Beam Computed tomography (CBCT), have been proposed. Both methods are reliable for the measurement of bone density, but preference is given to CBCT, due to the lower radiation doses, greater comfort for the patient and the lower prices. Pre-operatively defined bone density is a good indicator of the future success of implant therapy. In addition to the bone density, vascularity of the jawbone is an important factor of the quality of the bone for the osseointegration of dental implants. Laser Doppler is a simple method that can determine the vascularity of bone during implant insertion. The development of modern diagnostic methods for assessing the quantity and quality of the jawbone has enabled easier implant planning and has provided a secure outcome.

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

OBJECTIVES

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.

MATERIALS AND METHODS

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.

RESULTS

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 15 min 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.

CONCLUSIONS

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.

CLINICAL RELEVANCE

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.

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/purpose

Local 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 methods

Ten 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.

Results

IANB 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.

Conclusion

In 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.

Changes in human pulp blood flow during canine retraction

AIM

To evaluate the effects of maxillary canine retraction on pulpal blood flow (PBF) in humans as recorded by laser Doppler flowmetry (LDF).

METHODS

Maxillary canines of 24 participants were divided into two groups (n = 12 each). Teeth in the study group underwent maxillary canine retraction using mini-implants as anchorage for approximately 4 months, with 100 g of force applied via coil springs. Subjects in the control group received no orthodontic treatment. LDF measurements were recorded at baseline (T0); during retraction, at 24 hours (T1), 3 days (T2), 7 days (T3) and 1 month (T4); and at the end of retraction (T5) in the study group and at similar time-points in control subjects. Data were analyzed using the Friedman, Wilcoxon signed rank and Mann-Whitney U tests, with the significance level set at 0.05.

RESULTS

No significant changes in PBF perfusion units (PU) were observed in the control group over the course of the study. However, PBF in the study group increased significantly from T0 (3.6 ± 0.2 PU) to T1 (3.7 ± 0.2 PU, p < 0.001) and decreased severely from T1 to T2 (3.3 ± 0.1, p < 0.001). PBF in the study group was still significantly lower at T3 (3.4 ± 0.1 PU, p < 0.001) in comparison to T0; however, at T4 and T5, PBF was found to have returned to pre-retraction levels.

CONCLUSION

The fact that PBF values returned to initial levels within one month of the initiation of retraction despite short-term, hyperaemic, regressive changes demonstrates that the changes observed in PBF during canine retraction are reversible.

Laser Doppler Blood-Flow Signals from Human Teeth during an Alignment and Leveling Movement Using a Superelastic Archwire

Objective. The purpose of this study was to examine alterations in blood-flow signals (BFS) from human teeth during an alignment and leveling phase (superelastic wire 0.014′′) in a clinical orthodontic treatment using laser doppler flowmetry (LDF). Materials and Methods. Recordings were made in 12 maxillary left central incisors. The basal value of the BFS from each tooth (without orthodontic forces) was compared with the corresponding values of BFS during four periods of observation: 20 minutes, 48 hours, 72 hours, and one month after the activation of the orthodontic appliance. Results. Statistically significant decrease of BFS was observed at 20 minutes, 48 hours, and 72 hours (P < 0.05). No differences were found comparing BFS on day 30 and the corresponding basal values. Conclusion. Under real clinical conditions, a significant decrease in BFS was verified during the initial phase of the treatment, followed by a recovery on day 30.

Coherence-gated Doppler: a fiber sensor for precise localization of blood flow

Miniature optical sensors that can detect blood vessels in front of advancing instruments will significantly benefit many interventional procedures. Towards this end, we developed a thin and flexible coherence-gated Doppler (CGD) fiber probe (O.D. = 0.125 mm) that can be integrated with minimally-invasive tools to provide real-time audio feedback of blood flow at precise locations in front of the probe. Coherence-gated Doppler (CGD) is a hybrid technology with features of laser Doppler flowmetry (LDF) and Doppler optical coherence tomography (DOCT). Because of its confocal optical design and coherence-gating capabilities, CGD provides higher spatial resolution than LDF. And compared to DOCT imaging systems, CGD is simpler and less costly to produce. In vivo studies of rat femoral vessels using CGD demonstrate its ability to distinguish between artery, vein and bulk movement of the surrounding soft tissue. Finally, by placing the CGD probe inside a 30-gauge needle and advancing it into the brain of an anesthetized sheep, we demonstrate that it is capable of detecting vessels in front of advancing probes during simulated stereotactic neurosurgical procedures. Using simultaneous ultrasound (US) monitoring from the surface of the brain we show that CGD can detect at-risk blood vessels up to 3 mm in front of the advancing probe. The improved spatial resolution afforded by coherence gating combined with the simplicity, minute size and robustness of the CGD probe suggest it may benefit many minimally invasive procedures and enable it to be embedded into a variety of surgical instruments.

The Postural Autonomic Regulation of Pulpal Blood Flow

Evidence suggests that postural changes in systemic blood pressure may significantly affect blood flow in the dental pulp. This in vivo study examined the responses of pulpal perfusion, systemic blood pressure, and heart rate to postural changes in humans. The experiments were done on 21 premolars in 16 participants aged 20-31 yrs. Pulpal blood flow recordings were measured by means of a laser Doppler Flowmeter. A blood pressure monitor was used to record blood pressure and heart rate. All measurements were simultaneously recorded for 1 min, 5 min after participants made postural changes. Changing from supine to standing caused a significant reduction in pulpal perfusion, while heart rate and diastolic blood pressure increased significantly. A significant non-linear relationship was found between percentage changes in pulpal perfusion and heart rate resulting from standing up. We speculate that when patients arise from the supine position, the shift in venous blood to the legs transiently (2-10 sec) lowers venous return and cardiac output, causing less inhibition of the vasomotor center, which, in turn, results in increased heart rate and blood pressure, but a decrease in pulpal blood flow. These results suggest that pulpal blood flow is affected by postural change, presumably via the autonomic nervous system.