Shigaku = Odontology; journal of Nihon Dental College最新文献

Prosthodontic management of patients with implants of any kind will logically begin from the time at which the patient first presents for examination. It is essential that the patient be managed by an effective team. The restorative dentist, responsible for the ultimate restoration of the patient, should be a leading member of the implant team. The prosthodontist assumes ultimate responsibility for determination of fixture number and location based on prosthetic and functional needs. By carefully evaluating conditions with the other team members, the limitations and potential for fixture placement will be realized and consensus regarding treatment objectives will be achieved. This paper provides an overview of the restorative dentist's role in general patient assessment, in surgical and restorative treatment planning, and in the various stages of treatment from surgical placement through a range of definitive reconstructive procedures.

This paper deals with the results of the investigation of the facial nerves of chondrichthyes in order to consider the phylogenetic origin of the Chorda tympani in human. Six species of elasmobranchs (Chlamydoselachus anguineus, Cephaloscyllium umbratile, Squalus acanthias, Dasyatis akajei, Raja kwangtungensis and Mobura diabolus) were dissected under a stereoscopic microscope for this purpose, and the following results were obtained. Ramus palatinus and R. pre-spiracularis were observed as pre-trematic branches, while R. mandibularis externus, R. mandibularis internus and R. hyoideus originating from R. hyomandibularis were observed as post-trematicus of the facial proper in chondrichtyes. The rami intermedii indicated by Tanaka and Nakao (1979) were observed only in Dasyatis akajei. The R. hyomandibularis of Squalus acanthias had cutaneous branches, and the same branches were described in Chimaera by Takahashi and Kobayashi (1988). R. pre-spiracularis and R. mandibularis internus supply the floor of mouth in Squalus acanthias. As for the other chondrichthyes, R. mandibularis internus was only the one that could be found at the floor of mouth cavity under a stereoscopic microscope. From the observations described above and from previous studies, it may be concluded that the problem of whether the Chorda tympani is homologous with whether the pre- or post-trematicus of branchial nerves seems to depend on the animal species.

Presently we are mainly employing into our clinic the Osseointegrated implants as advocated by Dr. Brånemark. Very often general practitioners would ask which implant system is superior when comparing the Osseointegrated implants with apatite implant or ceramic implant which were developed in this country. The main difference between the Osseointegrated implants and all other implants is that the Osseointegrated implants possess the long term basic clinical data obtained objectively, a systemized technique, and the fact that long term safety has been established in edentulous patients. Therefore in order to compare the Osseointegrated implants with appatite implant or ceramic implant it is at the least necessary for the latter two to receive the type of investigation and researches that the Osseointegrated implants has been enjoying for the past 30 years and to possess the long term basic clinical data associated with such researches. With the circumstances as it is when we look into the future of implantology it will not be exaggerating to say that the Osseointegrated implants will dominate the field for the next 20 to 30 years. Thus we would like to limit ourselves to the Osseointegrated implants when we think about the future of implantology from the point view of the practice in prosthodontics. In the field of dental prosthodontics there are numerous areas in which present prosthodontic theories cannot cope with but by employing the Osseointegrated implants relatively high level treatment becomes a reality. Such problem areas include edentulous cases with severe resorbed ridges where treatment with prosthodontics is relatively difficult or edentulous cases with opposing natural dentition. Also treatment of missing tissue either from trauma or from surgery can be performed in a wider range using the Osseointegrated implants. Especially in treating the cleft palate cases which has a high existance rate in our country by using the Osseointegrated implants with attachment denture the number of surgery can be reduced sharply and remarkable recovery with adequate function can be expected. Furthermore treatment of congenital anadontia can not only be made easy but also adequate functional recovery can be expected. In the past for those special cases where orthodontic treatment was considered impossible because of the location of edentulous teeth now by placing fixtures and use them as the anchor teeth one can render orthodontic treatment effectively and yet in a shorter time span.(ABSTRACT TRUNCATED AT 400 WORDS)

Future development in implant prosthodontics should be based on the fundamentals of sound research and reliable clinical implementation. The goals should be to research the safety and efficacy of implants with regard to materials, host receptor site and interfacial zone; to develop acceptable uniform standards of evaluation; and to submit findings to scientific methods of analysis in determining benefit-to-risk factors. This presentation will offer a glimpse at some current developments in basic and clinical research focusing on studies in biocompatability and host acceptance; the implant-tissue interface; processes in osteogenesis related to vascularization of host sites; and bioengineering studies related to stress analysis and dimensional accuracy of impression systems for implants. The presentation will further describe future direction in research, training and implementation of services through development of an interdisciplinary team. A center is proposed to address the need for combined efforts in clinical and basic science research, the broad scope of implant utilization, and the teaching of implant procedures within an academic setting and to our colleagues.

The average life span of the Japanese has grown to 75.61 years for men and 81.39 years for women: both Japanese men and women have the longest life spans of any peoples in the world. The Welfare Ministry has urged a review of the social security system including medicine and pensions, and is seeking to establish lives worth living in our old age for the coming aging society, because there is no sign of the increase in the average life span slowing down. Various functions of the living body change physiologically with aging. Figure 1 shows a well-known graph showing "Changes in Physiological Functions with Aging" reported by Shock in 1971. It shows that systemic basic metabolism decreases almost linearly with age after about 30 years that reaches the peak of body functions, as well as almost all autonomic functions, including the kidney, lung, heart, and nerves. The speed at which functions decrease varies with organs. The age when functions begin to decrease differs between individuals. Generally, however, the ability of the eye to adjust makes us aware of aging at the earliest stage of life. The distribution of all elements comprising a body decreases with age, except for extracellular fluid. There are many difficulties in establishing lives worth living in old age, because of the fact that aged people suffer from reduced physiological and physical functions. The pleasure of eating may be one of the things that make life worth living. Many aged people seem to wish that they could enjoy meals as they did in their youth.(ABSTRACT TRUNCATED AT 250 WORDS)

The voltage gradient method for root canal measurement was evaluated in vivo and in vitro. For the evaluation in vivo, 25 single root teeth, were employed. The working length was measured by bipolor or monopolor electrode. After measurement, the electrode was fixed on the tooth, and the tooth was extracted. Radiograph was taken from 12 directions perpendicular to longer axis of tooth, and the relation between anatomical foramen, physiological foramen and the attained position of electrode tip was assessed. In the evaluation in vitro, 7 extracted teeth were used, for which the positions of anatomical foramen and physiological foramen had been determined in advance from radiograph, in order to determine the influence of the root canal irrigants and medicaments. The electrode was fixed on electronic calipers and direct reading of the movement. Root canal irrigants and medicaments were injected into root canal, and the measurements were evaluated. The results were as follows: (1) In the cases of 22 teeth measured by monopolar electrode in vivo, the electrode tip was within 0.5mm from physiological foramen except one tooth. (2) In the cases of 3 teeth measured by monopolar electrode in vivo, the electrode tip was within 0.4mm from anatomical foramen. (3) In the cases, where electrolyte solution was filled in root canal and measurement was made by bipolar in the evaluation in vitro, the results of measurement were stable, and the electrode tip tended to be slightly closer to coronal direction from physiological foramen. (4) In the cases where non-electrolyte solution was filled in root canal and measurement was made by bipolar electrode in the evaluation in vitro, the results of measurement were not stable, and the electrode tip tended to be closer to the apex from physiological foramen. (5) In the case of the evaluation in vitro, where electrolyte solution was filled in root canal and measurement was made by monopolar electrode, the electrode tip tended to be a little closer to the front than the anatomical foramen. (6) In the evaluation in vitro, where non-electrolyte solution was filled in root canal and measurement was made by monopolar, the measurement was not achievable. (7) 10% NaOCl solution was found to be very useful as electrolyte solution filled in root canal to search physiological foramen by this measurement method. The above results suggest that the voltage gradient method for root canal measurement is highly reliable because root canal morphology at the apex can be directly in identified.

A clinical trial was performed to examine the effect of ACDEMIN, a combination of lysozyme chloride and vitamins (manufactured by Grelan Pharmaceutical Co., Ltd.,; supplied by Takeda Chemical Industries, Ltd.). The subjects were 65 patients with slight to moderate symptoms associated with locally developed diseases including gingivitis, periodontitis, pericoronitis of the wisdom tooth and gingival abscess. Improvement of the condition was evaluated according to symptom on the basis of local findings examined prior to and 7 days after administration. Adverse effects were also evaluated in terms of discomfort. General improvement was determined on the basis of improvement in symptoms and general safety on the basis of a comprehensive assessment of the adverse effects. The usefulness of the drug was determined on the basis of general improvement and general safety as assessed above. The results were as follows: 1) Of the 65 patients who entered the trial, 62 completed the course of administration. 2) The rates of improvement ("slightly improved" or better) according to symptom were 65.6% for gingival inflammation, 40.0% for bleeding, 50.0% for pus discharge, 41.8% for swelling, 61.9% for local pain, 26.7% for mouth odor, 21.7% for color tone and 62.3% for discomfort. 3) The rates of usefulness ("slightly useful" or better) according to disease were 66.7% for gingivitis, 92.0% for periodontitis, 81.8% for pericoronitis of the wisdom tooth and 100.0% for gingival abscess. 4) The usefulness of the drug was graded "very useful" in 4 patients, "fairly useful" in 18, "slightly useful" in 31 and "not useful" in none, with an overall rate of usefulness of 85.5% ("faily useful" or better). 5) No patients presented symptoms indicating an adverse effect.

Unlabelled: With advancement of materials and techniques for tooth restoration and changes in public awareness, procedures for treating primary caries have gradually minimized scraping of the tooth. In other words, there is a tendency toward qualitative transformation in caries prevention, moving from tertiary to secondary prevention, and further to primary prevention. The present paper describes a filling method for primary caries using an enamel cavity technique and Light-activated composite resin.

Materials and methods: 1) Cleaning of the tooth surface with a polishing brush; 2) water rinsing and drying; 3) topical application of a caries detector; 4) moisture exclusion with a rubber dam, followed by scraping of the tooth with a carbide bur (#330; ISO, 008); 5) after scraping, removal of the carious lesion with a round bur (#1/2; ISO, 006); 6) formation of an enamel cavity in the adjacent pit and fissuer; 7) making of a bevel with a round diamond bur of 1.2mm in diameter; 8) etching; 9) water rinsing and drying; 10) application of bonding agent; 11) filling with Full-fil Compule and stepwise packing of the cavity, starting from a corner, with attention given to preventing bubbles; 12) make-up of the occlusal surface; 13) Polymerization with a polymerizing unit (Light activated); 14) occlusal equilibration; 15) margin correction with a trimming bur; 16) polishing.

A study was conducted to analyze how tooth extraction procedure would affect patient's physical equilibrium sensation, using the positional centric equilibrium measuring device. Forty-five health subjects, between the ages of 20 to 30, with no systemic nor equilibrium abnormalities were selected for this study. The results obtained were as follows. 1. No noticeable changes in the centric movement were observed during the postural change from a sitting to a standing position. 2. Centric movement was transiently increased immediately after the movement from a horizontal to standing position. The average arterial pressure was decreased immediately after the alteration in body posture, suggesting that changes in body posture may influence the controlling mechanism of BP. 3. Increases in the area and velocity of the centric movement were found immediately after and up to 10 minutes after, respectively, topical administration of the anesthetic. During this time span, no correlation found between centric movement changes and circulatory changes suggested that topical anesthesia might influence the recovery reflex via central nervous system. 4. The effect of the extraction procedure on the centric movement area and the anteroposterior centric movement speed lasted for 10 minutes after extraction. On the other hand, the increase in the velocity of bilateral centric movement as well as whole body centric movement was found up to a point immediately after extraction. No correlation was found between circulatory changes and centric movement changes. It therefore was assumed that the topical anesthesia affected the recovery reflex via central nervous system.

The responses of superior salivatory nucleus (SSN) neurons to electrical stimulation of ipsilateral orbital gyrus were investigated in ketamine anesthetized cats. A total of 52 SSN neurons were identified by the antidromic spike responses to stimulation of the right chorda tympani nerve. Thirty-three (63%) neurons responded with spikes to stimulation of the orbital gyrus. These neurons were also activated by stimulation of ipsilateral lingual nerve. Eleven (21%) neurons received the inputs from only the lingual nerve. Remaining 8 (16%) neurons failed to respond to stimulation of neither orbital gyrus nor lingual nerve. The latency of orbital cortically evoked responses was 16.5-42.0 msec (mean +/- S.D. = 28.6 +/- 6.9 msec, n = 33), and that to stimulation of lingual nerve was 6.5-15.5 msec (9.9 +/- 2.4 msec, n = 46), respectively. In this study, convergence of excitatory inputs from orbital gyrus and sensory nerve was found in 63% of SSN neurons. These inputs would play an important role in submandibular and sublingual salivation.