Motohide Ikawa

Revascularization of an immature permanent tooth with periradicular abscess after luxation

An immature permanent mandibular central incisor with periapical involvement in a 7-year-old boy was treated to promote revascularization. The tooth suffered from acute apical periodontitis after periodontal treatment by a general practitioner. An access cavity was prepared in the tooth and the cavity was left open until the next visit to achieve drainage through the canal. The root canal was not mechanically cleaned during the treatment period, but was irrigated with hydrogen peroxide and sodium hypochlorite. Calcium hydroxide compound was used for disinfection. At the fifth visit vital tissue appeared in the canal near the apical region, and calcium hydroxide compound was placed in contact with the soft tissue in the root canal. The access cavity was sealed with glass-ionomer cement followed by an adhesive composite resin filling. Radiographic examination 30 months after the initial treatment confirmed closure of the apex and thickening of the root wall. The case was observed for up to 13 years and root development was confirmed.

The effect of short-term tooth intrusion on human pulpal blood flow measured by laser Doppler flowmetry

The purpose was to examine the effect of brief intrusive forces on human pulpal blood flow (PBF). Laser Doppler flowmetric measurements were made from 17 vital upper left central incisors of 17 participants who had clinically healthy tooth crowns and periodontal tissues. Brief intrusive forces (0.5,1,5 N; duration 20 s) were applied to the incisal edges of the examined teeth, and apical displacement of the teeth and the PBF were measured simultaneously. Recordings were made with and without an opaque rubber dam applied to the examined teeth. Intrusive force significantly reduced PBF flux both with and without the dam (P<0.05, Friedman analysis). The results indicate that transient apical displacement can reduce PBF.

Scattering of laser light directed onto the labial surface of extracted human upper central incisors.

The purpose of this study was to evaluate the scatter of light through human teeth with laser Doppler flowmetry. An optical probe (probe 1), which mounted two optical fibers (one for light illumination and another for the measurement of backscattered light intensity) was placed on the labial surface of the extracted teeth. Another optical probe (probe 2) for the measurement of transmitted-light intensity was placed either on the mesial, distal, or palatal surface or in the canal of the teeth. The light intensity at probe 1 was stable, irrespective of the location of probe 2, whereas the transmitted light intensity at probe 2 tended to increase as probe 2 moved to more incisal positions on the mesial, distal, and palatal tooth surfaces. The results indicate that the light scatters to a wide area outside the tooth and provides information regarding the surrounding tissue blood flow.

OPTICAL CHARACTERISTICS OF HUMAN EXTRACTED TEETH AND THE POSSIBLE APPLICATION OF PHOTOPLETHYSMOGRAPHY TO THE HUMAN PULP

In order to record pulp blood flow by photoplethysmography, the light transmission properties of extracted human teeth and human peripheral blood at wavelengths between 400 and 800 nm were first investigated. Transmission through peripheral blood and extracted teeth was lower at wavelengths shorter than 600 nm. Transmitted-light photoplethysmography (TLP) was applied to teeth in situ using a tungsten light, or one of two light-emitting diodes (LED) with peak wavelengths of 565 and 695 nm. A CdS-CdSe photoconductive cell was used as a detector. The LED with a peak intensity at 565 nm was the most efficient of the three light sources for recording the TLP. The results indicate that the TLP could be used to assess pulp vitality.

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.

Age-related changes of pulpal blood flow in primary teeth measured by laser Doppler blood flowmetry

Abstract The purpose of the present study was to examine age-related change of the pulpal blood flow (PBF) in human primary teeth. PBF of 21 healthy upper primary central incisors in 12 children (age: 3 years 11 months–7 years 3 months) was measured by laser Doppler flowmetry (LDF). Recordings were made with and without opaque black rubber dam application. On 10 of the examined teeth, repeated measurements were made on different occasions: twice on 4 teeth (3 subjects) and 3 times on 6 teeth (3 subjects). The results obtained were as follows: PBF with dam application was significantly decreased with increasing age of the subjects ( P

The effects of thermal and mechanical stimulation on blood flow in healthy and inflamed gingiva in man

The purpose of this study was to compare the state of the microcirculation in healthy gingiva with that in untreated, inflamed gingiva in humans. Reflection photoplethysmography (RP) was used to record blood flow from 13 clinically healthy, attached gingival sites in seven adults and 11 inflamed sites in seven patients. Changes in the pulse amplitude of the RP signal were measured before and after application of thermal (cold and hot water) and mechanical (brushing) stimuli to the gingiva. Hot water and brushing, but not cold water, produced a significant increase in the pulse amplitude in healthy gingiva (p < 0.05, Friedman analysis and Student-Newman Keuls test). None of the stimuli produced a significant change in inflamed gingiva. In neither group of participants was there a significant correlation (Spearman rank correlation coefficient) between vascular responsiveness and age. The results indicated that vasomotor control may be impaired in inflamed gingiva.

Detection of the pulpal blood flow in primary teeth by laser Doppler flowmeter

Abstract In this study, pulpal blood flow (PBF) of human primary teeth was measured using laser Doppler flowmeter (LDF) and efficacy of opaque rubber dam application was examined. Twenty-two healthy and 3 non-vital upper primary central incisors in 13 children (age: 3 years 11 months–7 years 3 months) were examined. Recordings were made with and without opaque rubber dam application. Electrocardiogram (ECG) of the subjects was simultaneously recorded. Results obtained were as follows: 1) With dam application, pulsatile signals synchronous with ECG were recorded from all the healthy teeth, whereas no pulsatile signals were recognized in non-vital teeth. 2) Without dam application, pulsatile signals synchronous with ECG were recorded from all the healthy teeth and non-vital teeth. 3) The amplitude of blood flow signal was significantly reduced by the opaque dam application. Results indicated that PBF measurement using LDF with dam application in human primary central incisors was applicable for pulp vitality assessment.

Relation between blood flow and tissue blood oxygenation in human fingertip skin.

BACKGROUND Tissue blood flow (BF) is thought to be involved in the regulation of tissue blood oxygenation (StO2). The purpose of the present study was to show the relation between BF and StO2 by measuring them simultaneously under different conditions. METHODS Twenty-one healthy subjects (age 21-30years) participated in this study. We measured BF and StO2 in a small area of skin (fingertip, palm, forearm) simultaneously using a laser Doppler flowmeter and a tissue oxygenation monitor. Three measurements were made at rest while performing mental arithmetic and during constriction of the ipsilateral upper arm. RESULTS At rest, BF and StO2 were higher in the fingertip than in the palm or forearm (p<0.01). Performing mental arithmetic produced significant decreases in BF, oxygenated hemoglobin, and StO2 in the fingertip (p<0.05). Constriction of the ipsilateral upper arm produced significant decreases in BF and StO2 (p<0.05) and an increase in oxygenated hemoglobin (p<0.05). Both procedures produced significant increases in deoxygenated hemoglobin (p<0.05), which was in antiphase to the decrease in StO2. CONCLUSIONS BF decrease produced a significantly decreased StO2 in fingertip skin. The results show that simultaneous measurement of BF and StO2 is beneficial for showing the close relation between them.

Pulpal blood flow in human primary teeth with different root resorption

The purpose of this study was to examine the relation between the root resorption and the pulpal blood flow (PBF) in human primary teeth using laser Doppler flowmeter (LDF). Recordings were made on 15 clinically healthy upper primary central incisors in nine healthy participants (age: 3 years 11 months-7 years 3 months). The state of roots of the teeth examined were confirmed by radiographs. The mean PBF signals tended to decrease with the progress of the root resorption. Results indicated that PBF could indicate the status of the root resorption in the human primary teeth.