<ORIGINAL>A prospective randomized clinical study on the efficacy of CO_2 lasers on initial stage endodontics

The purpose of this study was to evaluate the clinical efficacy of the CO_2 laser in a prospective randomized trial. A total of 112 teeth in 112 patients, previously treated pulpectomy procedures were gathered and randomly divided into two groups composed of 56. Irradiation was performed on one group and non-irradiation forms of treatment were performed on the other group. On the first group of teeth, root canal enlargement was done and followed by exposure of the canal to a CO_2 laser light (5W, 200msec) using 3 cycles each at a rate of 15 seconds per cycle. The second group was not exposed to laser light following root canal enlargement. The laser was applied on the root canal for a controlled period of time. On the day following pulpectomy, a statistically significant (p < 0.05) fewer number of patients observed pain in the irradiation group compared to the non-irradiation group. The treatment times and the total treatment days in the irradiation group are shorter than in the non-irradiation group (p < 0.05). Multivariate analysis showed that the laser treatment was significantly associated with treatment times. This study shows that the degree of oral pain was greatly reduced in patients who underwent laser irradiation as compared to these who did not. Our study suggests that the use of laser treatment provide significant short-term improvement compared to conventional forms of treatment performed during pulpectomy

口腔上皮細胞に対するJuncus effusus L.水抽出物の抗炎症及び保護効果

Periodontitis is a chronic inflammatory disease caused by periodontopathogenic bacteria that form biofilms in periodontal pockets. The gingival epithelium acts as the first physical barrier in fighting attacks by periodontopathogenic pathogens, such as the primary etiological agent Porphyromonas gingivalis, and various exogenous chemicals, as well as regulates the local innate immune responses. Therefore, the development of novel oral care products to inhibit inflammatory reactions caused by bacterial infection and protect the gingival epithelium is necessary. Juncus effusus L. has generally been used as an indigenous medicine, such as a diuretic, an antipyretic, and an analgesic, in ancient practice. In this study, we examined the effects of a water extract from J. effusus L. on the inhibition of the inflammatory reaction elicited by bacterial infection and protection of the oral epithelium by chemical irritation. Pretreatment of oral epithelial cells with the water extract from J. effusus L. significantly reduced P. gingivalis or its lipopolysaccharide- (LPS-) mediated production of chemokines (interleukin-8 and C-C-chemokine ligand20) in a concentration-dependent manner with comparable to or greater effects than epigallocatechin gallate and protected oral epithelial cells from injury by chemical irritants, cetylpyridinium chloride, and benzethonium chloride. Moreover, the water extract from J. effusus L. in the presence of antimicrobial agents or antifibrinolytics already used as ingredients in mouthwash could significantly reduce the production of chemokines from P. gingivalis LPS-stimulated oral epithelial cells in a concentration-dependent manner. These findings suggest that the water extract from J. effusus L. is potentially useful for oral care to prevent oral infections, such as periodontal infections, and maintain oral epithelial function

Idiopathic Bone Cavity of the Mandible

A case of an idiopathic bone cavity is presented and discussed. The patient was a 54-year-old Japanese male with a history of stomach carcinoma operation and hospitalization two years ago. He was referred to the Department of Dental Radiology with a panoramic radiograph performed by the dentist. The panoramic radiograph demonstrated a well-defined elliptical radiolucent lesion near the right angle of the mandible, situated below the mandibular canal and slightly above the inferior border of the mandible. The patient stated that the lesion progressed asymptomatically without any sensation. From the lesion was indicated, the patient was greatly anxious about metastasis of stomach carcinoma to the mandible. To define the diagnosis of the lesion, intraoral radiography, extraoral radiography, tomography, and sialography were carried out. All results showed that the lesion was an idiopathic bone cavity without relationship to salivary gland tissue. No biopsy was carried out, but the lesion was diagnosed to be benign, and a metastatic carcinoma was ruled out

Individual Radiation Exposure Dose Due to Support Activities at Safe Shelters in Fukushima Prefecture

Immediately after the accidents in the nuclear power stations in Fukushima on March 11, the Japanese Government ordered the evacuation of the residents within a 20-km radius from the station on March 12, and asked various institutions to monitor the contamination levels of the residents. Hirosaki University, which is located 355 km north of Fukushima City, decided to send support staff to Fukushima. This report summarizes the results of the exposure of 13 individual teams from March 15 to June 20. The support teams surveyed more than 5,000 people during this period. Almost all subjects had external contamination levels of less than 13 kcpm on Geiger-Müller (GM) survey meter, which is categorized as “no contamination level.” The 1st team showed the highest external exposure dose, but the 4th team onward showed no significant change. Subsequently, the internal radiation exposure was measured using a whole body counter that indicated undetectable levels in all staff members. Although the measured external radiation exposure dose cannot have serious biological effects on the health of an individual, a follow-up study of the residents in Fukushima and other regions where the radioactive material has spread will be required for a long time

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口腔領域の悪性血管内皮腫は,ほとんどの場合,X線検査のみによって,診断や術後観察が行われてきたといえる。われわれは,本腫瘍の術後観察を,RIアンギオグラフィーと骨シンチグラフィーで行い,X線所見と比較検討した。得られたRIアンギオグラムは,下顎骨正中部における血流量の減少を示し,骨シンチグラムは同部の骨欠損像を示した。これらの所見から,本腫瘍の診断や術後観察に,RIアンギオグラフィーや骨シンチグラフィーは,極めて有用であろうと考えられた。A case of malignant hemangioendothelioma is presented in which the postoperative observation was carried out by means of radionuclide angiography and bone scintigraphy with 99m-Tc labeled methylene diphosphonate. In addition, these two modalities were compared with conventional dental radiography. The angiographic images obtained as a serial scintigrams from the first pass revealed an extremely decreased bone blood flow in the incisor region of the mandible, in which the radiographic images could not be contrasted without contrast media. The static scan bone images showed a well defined bone defect corresponding to the angiographic images and radiographic images. All findings obtained using these modalities showed that radionuclide angiography and bone scintigraphy were useful in following up the postoperative progress of malignant hemangioendothelioma

<CLINICAL REPORT>Computed Tomography and Ultrasound Study in Craniofacial Fibrous Dysplasia

24歳の女性に認められたcraniofacial fibrous dysplasiaの検索に際して,病変の範囲を確認する目的で,CT検査と超音波検査を行った。また,病変が単骨peであるか多骨性であるかを鑑別するために^TC標識methylene diphosphonateによる骨シンチグラフィーを実施した.CT検査により,右側下顎骨に存在する嚢胞様病変と右側上顎骨に存在する骨性病変が明かにされた。また,骨性病変の著しい増大による右側上顎洞と右側篩骨洞の縮小も明らかとなった。超音波検査では,病変の細部にわたる観察は不可能であったが,右側上顎骨における骨性病変の存在と,右側下顎骨の著しい膨隆を確認することが可能であった。骨シンテグラフィーでは,顎顔面領域に強い陽性像を認めるものの,その他の骨格系には何らの異常も認められなかった。従って,本症例は,polyostotic fibrous dysplasiaの1型であるcraniofacial fibrous dysplasiaであるとの鑑別が可能であった。In diagnosing craniofacial fibrous dysplasia observed in a 24-year-old woman, computed tomography and ultrasound study were used to define the extent of the bony lesions. Bone scintigraphy with ^Tc labeled methylene diphosphonate was also carried out to differentiate the disease to be monostotic or polyostotic. The sagittal and coronal scan CT images showed a monocystic bony lesion with a mottled appearance in the right mandible, which was growing toward the ramus. The axial scan CT images demonstrated a thickened ramus in the right mandible, an expansible bony lesion in the right maxilla, an increased osseous mass occupying the almost half of the right maxillary sinus, and the almost entirely closed right ethmoidal sinus. Expansible diploe in the right side of the patient\u27s skull was also observed. The ultrasound images with axial scans revealed an expansible lesion in the right mandible and an osseous mass in the right maxilla. The bone scan images showed no abnormalities in the whole body skeleton except for the remarkable uptakes in the craniofacial regions

本学ヘリカルCT (ProSpeed F II)における空間分解能の評価

The image precision of a computed tomograph (CT) installed at our university was evaluated from a dental-clinical viewpoint. The effective slice width and spatial resolution were measured by photographing 0.3mm diameter microspheres. The results, with a set slice width of O.6mm, resnlted in an effective slice width in a helical pitch of 0.75 of 1.3mm and the spatial resolution was 0.64mm. With a slice width of 1.0mm, the effective slice width in a helical pitch of 0.75 was 0.92mm and the spatial resolution was 1.06mm. The following conclusions were obtained : 1. Even when the set slice width is smaller than 1 mm, the effective slice width is not rednced but it is possibile that the smaller width will resnlt in lower precision. 2. With decreasing helical pitch, the difference between the set slice width and the effective slice width decreases. 3. Smaller slice widths, result in better resolution. 4. It was inferred that there is an error of 0.6 - 1 mm in the dimensional precision of the images, which are used clinically in the z axis direction

本学ヘリカルCT(ProSpeed F II)における距離計測の精度評価

In order to evaluate image precision of a computed tomography (CT), acrylic and glass cubes soaked in the water were scaned and length was measured on a constructed image. The following conclusions were obtained from the above-mentioned results: 1. Length is different from that of the actual size according to software used for measurement in some cases. 2. Length of glass cubes with a high CT number tends to be measured longer than the actual one in comparison with acrylic cubes. 3. An error is apt to occur in the peripheral part due to the partial volume effect. 4. Difference in precision in the Z axis direction caused by the scan method is not observed. 5. Increase of errors towards the Z axis direction accompanying movement of the table is within the allowable range but should be considered clinically

超音波パワードプラ表示法による耳下腺領域の血流の検討

The purpose of this study is to evaluate whether Power Doppler imaging can demonstrate the characteristics of arterial blood flows around the parotid gland and to calculate the means of blood flow velocities. Among the external carotid arteries the characteristics of arterial blood flows in the facial artery, superficial temporal artery, and middle temporal artery, both in the lengthwise and transverse sections could be depicted. There were differences in the means of the velocities, the pulsatility index (P. I.), and the resistance index (R. I.) between these various arteries. Power Doppler imaging appears to be valuable in the diagnosis of blood flows around the parotid gland

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Predictive factors for understanding in fundamental radiology study were statistically evaluated on dental education. The investigation was made with 86 students in the fourth grade dental school in the 1999 school year. The average points in the test of fundamental radiology were compared for each group divided by predictive factors. The relationship between the total points scored and the predictive factors were analyzed by multivariate analysis. The statistical results showed that learning physics in high school made a significant contribution to understanding fundamental radiology. Teaching physics in the university was found to be very important for understanding in fundamental radiology study