Abstract : The discovery of HIV and its clinical, epidemiological and pathological studies leave no doubt in the etiology of AIDS, while Duesberg and his Japanese follower Nishioka raised questions about the AIDS etiology. Their opinions have no novel clinical or experimental grounds but are only caused by their misreading of the references on AIDS. We show here how they misread the references and inform another AIDS debate challenged by Duesberg in the overseas countries where Nature played the main role to support the authors against Duesberg.

Abstract : Roentgenologic examination has important roles for the diagnosis of horizontal root fracture. Recently, an instrument of multi-functional panoramic tomography (MPT) has been developed and used for determinations of bone width before dental implantation and the position of impacted tooth. The images obtained by the instrument are thought to provide valuable informations for diagnosing a horizontal root fracture.

 In this study, we compared the sagital images of the dry skull obtained by MPT and those by a apical projection which is used in dental fields and computed tomography (CT). The first incisor tooth with horizontal root fractures was implanted in the alveolar socket in the upper right side of the dry skull. The widths of split fractures were 0.07 and 0.5 mm.

 In the images produced by the apical projection, either of the fracture lines of 0.07 and 0.5 mm in width, the pulp chamber or its surrounding bones was clearly observable, whereas in the sagital MPT images, the two fracture lines were observed, but the line of 0.07 mm was nuclear and the pulp chamber and the surrounding bones were not observable. In the CT images, it was possible to only find the fracture line of 0.5 mm, but both the pulp chamber and the surrounding bones were unclear.

Abstract : In our endodontic treatment, we usually confirm the germfree state at root apex before root canal filling using the Chair-side anaerobic incubation system. In this time, we recalled 250 cases after 1 to 3 years. As a result, 98.8% of the cases were progressing favorably after root canal filling. Bacteria were isolated from the rest of cases (3 cases) which showed clinical symptoms or radiolucency at root apex. These results strongly indicate that the Chair-side anaerobic incubation system is necessary for endodontic treatment.

Abstract : The purpose of this study was to compare the working time and apical leakage of the lateral condensation method with those of continuous wave of obturation technique. One hundred and sixty-seven root canals of 60 human molars stored in distilled water were prepared using Profile .04 tapers driven by the Tri Auto ZX at manual mode in a crown down sequence. The teeth were divided into 4 groups after the root canal preparation was completed. Group 1 canals (n=41) obturated with the lateral condensation technique served as controls. Group 2 (n=43), 3 (n=40) and 4 (n=43) canals were obturated with continuous wave of obturation technique using the System B for down-packing and the Obtura Ⅱ for back-packing. In groups 2, 3 and 4, a nonstandardized master cone (Kerr), a standardized master cone (GC) and warmed gutta-percha injected by Obtura Ⅱ were used for down-packing, respectively. Tooth apices were immersed in india ink and cleared to measure the length of dye penetration. Each working time of 3 experimental groups (34.6, 36.2 and 37.0 seconds for group 2, 3 and 4, respectively) was significantly shorter than that of the control group (78.1 seconds, one way-ANOVA, p<0.05). No difference was found in dye leakage along the main canal among the four groups (0.60, 0.88, 0.98 and 0.91 mm for group 1, 2, 3 and 4, respectively, one way-ANOVA, p>0.05). The continuous wave of obturation technique using the System B and Obtura Ⅱ showed a satisfactory seal and shorter working time for the root canal obturation.

Abstract : Marble bone disease is general osteosclerosis.

 Such a patient rarely to be found.

 In spite of osteosclerosis, the patient easily suffer fracture, thier teeth are hypocalficication, have a lnfection due to extraction of tooth. Osteomyelitis is inflammammatory disease that is resistant to treatment.

 In x-ray phtograph, bone and root is difficult of diagnosis.

 Endodontist should treat more carefully in root canal.

Abstract : We could not make a precise diagnosis for complaint of a pain in the maxillary canine area in this patient. After all, tooth in due was the proximal first premolar. The reason of misdiagnosis might be due to that the root canal treatment of maxillary first premolar had ever been performed and the progression was favourable, furthemore, chief complaint of this patient was a pain in the apex area of maxillary canine. At last we found the small cyst on the apex of the first premolar by flap operation for differentiation. As a result of apicoectomy, discomfort was entierely relieved. The pain in the area of canine may have been ‘referred pain’ by first premolar.

Abstract : In dental procedure, emphysema sometimes occurs by careless using of air turbine or air syringe. Especially, when hydrogen peroxide (H₂O₂) is used for root canal irrigation with syringe at root canal treatment, much oxygen generate rapidly from the interaction with catalase in case of bleeding. In this case report, pulpectomy of upper right canine was done on the patient who had history of the right maxillary sinusectomy about 38 years ago. 15% EDTA, 1% NaClO and 3% H₂O₂ were used for root canal irrigation after pulpectomy. But, bleeding in root canal did not stop after using those irrigants. Then, physiosaline solution was used as a irrigant to stop bleeding. Apical foramen was not destroyed by instrumentation, and gave apical stop with #25 k-file. However, patient complained feeling of swelling on the right face after these procedures. Emphysema with internal hemorrhage was observed on the right face and the oral mucous membrane. Antibiotics, anti-inflammatory drug and hemostatics were prescribed to patient. After two days, emphysema with internal hemorrhage has been spreading from the right to left face. This symptom disappeared after 30 days. It was thouht that bone of canine fossa and peri-apical bone of canine were destroyed due to the operation. It is reported that emphysema disappears usually in a week. However, it took 30 days for healing up. We have to be very careful at root canal irrigation like the present case for prevention of emphysema.

Abstract : It is very important to use high quality mask in the dental office that is fulled of contaminated aerozol.

 When mask is set to the face, we must investigate if there is leak or not.

 FT-10 fit tests, with, ① ear loop type mask, ② tie loop type mask, ③ N95 type mask, and the result is that N-95type mask is the best.