• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1204-1209
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• 2012

To diagnose dental pulp vitality, electric pulp tester has been widely used, which is a method to test condition of nerve. However, especially in the case of patients with trauma, nerve desensitization could temporarily occur even though nerve might be recovered by blood flow within the pulp later, which implies that blood flow in dental pulp is also an important factor for diagnosing vitality. This paper described the development of a probe that relatively measured blood flow in dental pulp using photoplethysmography (PPG). The probe emits four different wavelength light sources including three visible and an infrared light. We tested which light source detect sensitively the blood flow in dental pulp. As a result, green light had the largest peak to peak voltage and the power spectrum among different wavelengths.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.375-384
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• 1996

The purpose of this study was to investigate the functional involvement of sympathetic nerve in the control of the microcirculation in the dental pulp with the aim of elucidation of the involvement of neuropeptides and sympathetic nerve in neurogenic inflammation. Experiments were done on the 7 cats anesthetised with sodium pentobarbital, and sympathetic nerve to the' dental pulp was stimulated electrically (10 Hz, 4 V, 1.5 ms, 3.5 mins). Ana-adrenoceptor antagonist phentolamine and a neuropeptide Y antagonist D-myo-inositol-1,2,6-trisphosphate (PP56) were injected close intra-arterially into the dental pulp without changing the systemic blood pressure. The probe of laser Doppler flowmeter was placed on the buccal surface of ipsilateral canine teeth to the stimulation, and pulpal blood flow was measured. Stimulation of the sympathetic nerve decreased pulpal blood flow by $55.24{\pm}7.74\;%$ (mean${\pm}$SEM, n = 13). Stimulation of the sympathetic nerve following the injection of the ${\alpha}$-adrenoceptor antagonist phentolamine ($0.1{\mu}g$/kg) caused decrease of pulpal blood flow by $14.35{\pm}3.43%$ (mean${\pm}$SEM, n=5). Phentolamine attenuated the sympathetic nerve-induced pulpal blood flow decrease by $74.02{\pm}9.32%$ (mean${\pm}$SEM) Stimulation of the sympathetic nerve following the injection of the neuropeptide Y antagonist PP56 (2.3 mg/kg) caused decrease of pulpal blood flow by $30.64{\pm}7.92%$ (mean${\pm}$SEM, n=6). PP56 attenuated the sympathetic nerve-induced pulpal blood flow decrease by $44.37{\pm}11.01%$ (mean${\pm}$SEM). These data provide evidences of the co-contribution of nerepinephrine and neuropeptide Y on the sympathetic nerve-induced vasoconstriction in the feline dental pulp. In addition, they show functional evidences that sympathetic nerve plays an active role in controlling the microcirculation of the dental pulp.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.366-374
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• 1996

The purpose of this study was to investigate whether D-myo-inositol-l,2,6-trisphosphate (PP56) can effectively antagonize vasoconstriction caused by neuropeptide Y in the dental pulp, and to understand involvement of neuropeptide Y in the regulation of microcirculation in the dental pulp with the aim of elucidating neurogenic inflammation. Experiments were performed on 7 cats anesthetised with sodium pentobarbital, and neuropeptide Y and a neuropeptide Y antagonist PP56 were injected close intra-arterially into the dental pulp. The probe of laser Doppler flowmeter was placed on the buccal surface of ipsilateral canine teeth to the drug administration and pulpal blood flow was measured. Intra-arterial injection of neuropeptide Y (1.3-$2.0\;{\mu}g$/kg) resulted in pulpal blood flow decrease of $37.73{\pm}5.73%$(mean${\pm}$SEM) (n=9). Intra-arterial injection of PP56(0.3 mg/kg) alone changed pulpal blood flow little by 1.03 % reduction. The effect of neuropeptide Y in the presence of PP56 resulted in significantly less decreases in pulpal blood flow ranging from $27.17{\pm}5.37$ to $16.63{\pm}3.48%$ from control as compared with neuropeptide Y alone(n = 13). In effect, PP56 attenuated pulpal blood flow caused by neuropeptide Y. Results of the present study have provided evidences that a non-peptide PP56 is capable of antagonizing vasoconstriction caused by neuropeptide Y in the feline dental pulp. In addition, they show functional evidences that neuropeptide Y plays an active role in modulating the microcirculation of the dental pulp.

• The korean journal of orthodontics
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• v.39 no.6
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• pp.372-382
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• 2009

Objective: This study was to change of pulp blood flow among maxillary and mandibular anterior tooth with mild crowding and adjacent teeth using Ultrasound Doppler graphy. Methods: The change of pulp blood flow was measured three times using Ultrasound Doppler graphy; before the attachment of brackets, after 3 week, and after 6 week. The sample consists of 15 year old eighteen patients. Results: Before the attachment of brackets, after 3 weeks, and after 6 weeks, there were no significant differences in the change of pulp blood flow in each part (maxilla and mandible) and each tooth according to period. In addition, to compare internal dangerousness of loss of the pulp vitality, when pulp blood flow is compared in each tooth before orthodontic treatment, there were no statistically significant differences in maxillary lateral incisor and mandibular canine but it showed low values in all measurement items (p > 0.05). Conclusions: Results of this study can be not only methodological preliminary data in further study such as tooth movement type of Ultrasound Doppler graphy and particular study considered the patient age, but also reference materials for the loss of pulp vitality in orthodontic treatment.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.560-569
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• 1999

Blood supply rather than nerve supply implies pulp vitality. To evaluate pulp vitality clinically, electric pulp test and thermal test which are based on sensory nerve response have been used in addition to many auxiliary data such as past dental history, visual inspection, radiographic examination, percussion, palpation and transillumination test. However, reactivity of the nerves to the stimulation is not synonymous with normalcy. Therefore measurement of pulpal blood flow using a laser Doppler flowmeter became a new trial to test the pulp vitality. The purpose of the present study was to evaluate normal pulpal blood flow level of maxillary teeth in adult to provide a guideline in determining the vitality of dental pulp. Pulpal blood flow was measured in maxillary central and lateral incisors, canines, first and second premolars and first molars of seventy nine adults of 22 - 30 years old using a laser Doppler flowmeter (PeriFlux 4001, Perimed Co., Stockholm, Sweden, 780 nm infrared laser, 1mW). For directly-made splints, silicone rubber impressions were taken directly from the mouth. For indirectly-made splints, alginate impressions were taken from the mouth and stone cast were made. After making depressions on the buccal surfaces of the cast teeth to indicate the hole positions, second impressions with vinyl polysyloxane putty were taken from the cast. Holes for the laser probes were made at the putty impressions 4mm above the gingival level. Laser probe (PF416 dental probe, 1.5mm) was inserted in the prepared hole and the splint was set in the mouth. After 10 minutes of patient relaxing, pulpal blood flow was recorded for 5 minutes on each tooth. The recorded flow was saved in the computer and calculated with a software 'Perisoft' version 5.1. Pulpal blood flow was also recorded in six teeth of five individuals with no response to electric pulp test and cold test, with periapical radiolucency, or with history of root canal treatment to compare with nonvital teeth. The difference between the mean flow values of each group of teeth were analyzed using one-way ANOVA and Duncan's Multiple Range test. The results were as follows: 1. The average pulpal blood flow values of all the tested teeth of each location were between 9 - 16 Perfusion Unit. Pulpal blood flow value was highest in maxillary lateral incisors, followed by first premolars, second premolars, canines, central incisors, and then first molars (p<0.01). 2. In six anterior teeth, indirectly-made splint group showed higher pulpal blood flow values than directly-made splint group (p<0.01). In posterior teeth, however, there was no significant flow value difference between directly-made splint group and indirectly-made splint one (p>0.05). 3. Teeth with vital pulps showed higher signal values than teeth with nonvital pulps (p<0.01), and the flow photographs showed heartbeat-synchronous fluctuations and vasomotions, while those were absent in non vital tooth.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.202-209
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• 2016

Objectives: The purpose of this study was to investigate the involvement of TRPA1 in the cinnamaldehyde-induced pulpal blood flow (PBF) change in the feline dental pulp. Materials and Methods: Mandibles of eight cats were immobilized and PBF was monitored with a laser Doppler flowmetry at the mandibular canine tooth. To evaluate the effect of cinnamaldehyde on PBF, cinnamaldehyde was injected into the pulp through the lingual artery at a constant rate for 60 seconds. As a control, a mixture of 70% ethanol and 30% dimethyl sulfoxide (DMSO, vehicle) was used. To evaluate the involvement of transient receptor potential ankyrin 1 (TRPA1) in PBF change, AP18, a specific TRPA1 antagonist, was applied into the pulp through the Class V dentinal cavity followed by cinnamaldehyde-administration 3 minutes later. The paired variables of experimental data were statistically analyzed using paired t-test. A p value of less than 0.05 was considered as statistically significant. Results: Administration of cinnamaldehyde (0.5 mg/kg, intra-arterial [i.a.]) induced significant increases in PBF (p < 0.05). While administration of a TRPA1 antagonist, AP18 (2.5 - 3.0 mM, into the dentinal cavity [i.c.]) caused insignificant change of PBF (p > 0.05), administration of cinnamaldehyde (0.5 mg/kg, i.a.) following the application of AP18 (2.5 - 3.0 mM, i.c.) resulted in an attenuation of PBF increase from the control level (p < 0.05). As a result, a TRPA1 antagonist, AP18 effectively inhibited the vasodilative effect of cinnamaldehyde (p < 0.05). Conclusions: The result of the present study provided a functional evidence that TRPA1 is involved in the mechanism of cinnamaldehyde-induced vasodilation in the feline dental pulp.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6340-6345
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• 2013

This study examined the involvement of histamine in heat-induced changes in pulpal blood flow(PBF) to determine the mechanism of neurogenic inflammation in feline dental pulp. The experiments were carried out in 10 felines anesthetized with sodium pentobartial and histamine injected into the dental pulp through the external carotid artery. The change in the pulpal PBF was measured using a laser Doppler flowmeter(Periflux 4001, Stockholm, Sweden). The probe of laser Doppler flowmeter was placed on the buccal surface of the ipsilateral canine teeth. Heat was applied to the tooth using a heat stimulator controlled script file with an input/output device. The application of heat ($40-65^{\circ}C$) induced a significant increase in PBF. The application of histamine($5{\mu}g/kg/1ml$) followed by heat($45^{\circ}C$) resulted in an increase in PBF. Therefore, the results of the present study showed that heat and histamine are capable of vasoconstriction caused by neurogenic inflammation in feline dental pulp. In addition, neurogenic inflammation plays an active role in modulating the microcirculation of the dental pulp.

• Restorative Dentistry and Endodontics
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• v.29 no.3
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• pp.239-248
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• 2004

The purpose of this study was to investigate the influence of NK1 receptor antagonists on the pulpal blood flow (PBF) when applied iontophoretically through the dentinal cavity of the teeth in order to understand whether iontophoretically applied NK1 receptor antagonists can control the pulpal inflammation. Eleven cats were anesthetized with alpha-chloralose and urethane, and substance P (SP) was administered to the dental pulp through the catheterized lingual artery in doses that caused PBF change without the influence of systemic blood pressure. NK1 receptor antagonists were applied iontophoretically to the prepared dentinal cavity of ipsilateral canine teeth of the drug administration, and PBF was monitored. Data were analyzed statistically with paired t-test. PBF increase after iontophoretic application of the NK1 receptor antagonists followed by the intra-arterial administration of SP was significantly less than PBF increase after iontophoretic application of the 0.9% saline followed by the intra-arterial administration of SP as a control (p < 0.05). Iontophoretic application of the NK1 receptor antagonists (0.2~3.4 mM) following the intra-arterial administration of SP resulted in less increase of PBF than the iontophoretic application of the 0.9% saline following the intra-arterial administration of SP as a control (p < 0.05). Therefore. the results of the present study provide evidences that the iontophoretic application is an effective method to deliver drugs to the dental pulp. and that iontophoretically applied NK1 receptor antagonists block SP-induced vasodilation effectively. The above results show the possibility that the iontophoretical application of NK1 receptor antagonists can control the neurogenic inflammation in the dental pulp.

• Restorative Dentistry and Endodontics
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• v.36 no.2
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• pp.149-153
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• 2011

As the dental pulp is encased with a rigid, noncompliant shell, changes in pulpal blood flow or vascular tissue pressure can have serious implication for the health of pulp. Numerous studies have demonstrated that orthodontic force application may influence both blood flow and cellular metabolism, leading degenerative and/or inflammatory responses in the dental pulp. The aim of this case report is to present a case about tooth with chronic periapical abscess which showed normal vital responses. Excessive orthodontic force is thought to be the prime cause of partial pulp necrosis. Owing to remaining vital tissue, wrong dianosis can be made, and tooth falsely diagnosed as vital may be left untreated, causing the necrotic tissue to destroy the supporting tissuses. Clinician should be able to utilize various diagnostic tools for the precise diagnosis, and be aware of the endodontic-orthodontic inter-relationship.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.546.1-546
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• 2003

Laser doppler flowmeter (LDF) has been applied to the measurement of pulpal blood flow (PBF) in human teeth. As far as we searched, the detection area of the pulp in the blood flow measurement has not been clarified, yet. Therefore, the purpose of this study was to obtain information of the detection area in PBF measurement using LDF. The experiments were performed on the artificial blood circulation in extracted human upper central incisors. The apical portions of examined teeth (n=6) were severed and root canals were enlarged from the apical end to the 2mm incisal to the level of enamel-cement junction. An individual resin cap of each tooth was prepared and a hole was drilled 2mm incisal to enamel-cement junction of the labial side of the cap. The measurement probe of LDF (MBF3D, Moor Instrument, UK) was plugged into the hole of the cap. Heparinized human peripheral blood, which was in advance collected and diluted 3 times with physiological saline, was pumped through the apical foramen of the teeth via a silicone tube and a disposable needle (o.d. 0.7mm) and blood flow signals were monitored. The flux signal significantly increased with the enlargement of the root canal to incisal direction (p<0.01, Friedman analysis). The result indicates that the performance of LDF in PBF with human teeth is limited.