ブラジルの歯科事情

The purpose of this article is to introduce Brazil from a dental point of view. Some aspects of Brazilian cultural life and economics that influence oral health and esthetics are presented. The Brazilian dental educational system, tuition fees and ranking of dental schools are compared and contrasted with those in Japan. In Brazil, there are 92 dental schools while in Japan there are 29. Dental schools in Brazil are classified according to their administration into national public schools, state public schools, and private schools. The University of Sao Paulo (U. S. P.) which is the most well recognized and largest university in South America, has three dental schools. The dental school of the Sao Paulo has the largest campus and a population of 715 students. Japanese descendants have a great influence over U. S. P. life. About 30% to 50% of the enrollment in prestigious courses such medicine, dentistry and engineering is filled by students of Japanese descent. The incidence of dental caries and periodontal disease are still extremely prevalent in Brazil, as in other developing countries, contrary to what has been observed in developed countries. Recent data issued by the Brazilian National Oral Health Survey (1994) observed a DMFT of 4.8 among 12-year-olds. In Japan, the National Dental Disease Survey conducted by the Ministry of Public Welfare (1993) revealed a DMFT of 3.64 for the same age group. Socioeconomic differences are seen as the principal cause of the discrepancy

日本人skeleatl I, skeletal III症例の歯列弓と顎顔面頭蓋における形態学的関係に関する研究

Available studies about differences among races, related to prevalence of malocclusion or morphology of head and dental arches, suggest a hypothesis that the high prevalence of skeletal Class III malocclusion in Asian ancestry populations could be correlated with a tendency toward a brachycephalic head form and larger arches widths. The purpose of the present study was to evaluate anteroposterior relationship of upper and lower jaws associated to form of dental arches, maxilla, mandible, face and head. Materials in this research consisted of pretreatment lateral and posteroanterior cephalometric radiographs and orthodontic models of Japanese females with skeletal Class I and Class III. Strong correlations between head form and jaws anteroposterior relationship could not be found. However, results indicated that skeletal Class III have statistically significant smaller length of maxilla and greater length of mandible, than the skeletal Class I group. Moreover, basal arch length and width of mandible were significantly bigger in skeletal Class III group. These results suggest that skeletal Class III, at least in this sample, might be associated to local malformation factors

顎整形力を用いた上顎骨前方歯槽部の後方移動時におけるコルチコトミーの効果に関する研究

The dry skulls of two adult female Japanese macaques were used in this study of bone strains produced by corticotomy combined with orthopedics. The directions and magnitudes of the principal strains were measured using an eight-pair triaxial strain gauge rosette. While compressive strains were seen in the control study (orthopedic force alone before corticotomy), tensile strains were seen in the experimental study (orthopedic force after corticotomy) on the frontzygomatic suture, the lateral side of the zygomaticomaxillary suture of the zygomatic bone, and on the maxillary bone. Corticotomy, combined with the posterior transfer of the anterior segment, had the following effects : in the control study, traction was diffused though the maxillofacial structures, while in the experimental study, it did not readily diffuse because the compact bone was separated. This resulted in favorable conditions for the posterior transfer of the anterior maxillary segment between the maxilla proper and the maxillary alveolar bone which are connected only by trabecular bone. These results demonstrate the usefulness of combining a corticotomy with retraction of the maxillary anterior segment by orthopedic forces. A clinical case of Class II malocclusion is presented to illustrate what can be accomplished with treatment by corticotomy. The treatment objectives were achieved with improvement in the patient\u27s profile and in the function and esthetics of the dentition

4-META MMAレジンで接着した矯正用ブラケットの再接着時における圧縮剪断荷重について

The purpose of this study was to determine the difference of the shear bond strength between new and rebonded brackets with a chairside cleaning method proposed by the authors. A preliminary study was carried out to examine the optimal cleaning time for both 4-META MMA resin (Superbond, Sun Medical, Kyoto, Japan) and Bis-GMA resin (Concise, 3M, Monrovia, California, USA) using acetone or chloroform. The 4-META MMA resin was completely removed by acetone (13 min.) and by chloroform (8 min.), while the Bis-GMA resin was not removed by either. The resin remnant on the bracket base was stained with alcohol-based ink and analyzed quantitatively under a microscope attached to a CCD camera and a computer analyzer. Stainless steel brackets with foil mesh base designs were bonded to twenty extracted human premolars with the 4-META MMA resin. All specimens were stored in water at 37℃ for 24 hours, and thermocycled 120 times from 4℃ to 60℃ before shear bond strength testing. Specimens were stressed to bond failure using an Autograph AG-5000D testing machine (Shimadzu, Kyoto, Japan). The bases of the debonded brackets were inspected for resin according to an adaptation of the adhesive remnant index (ARI) system. After recording of the shear bond strengths, the brackets were cleaned and rebonded to the same teeth and tested once more. The results revealed that the rebonding of the brackets even twice following the original bonding had no significant effect on the bond strength value. The capacity for rebonding of the same bracket by an easy and fast cleaning method is an advantage of the 4-META MMA resin over the Bis-GMA resin

Preparations for Endosseous Implants. Part 2. : Laying stress on the method of measuring the efficiency of the insertion guide

As a preparation for endosseous implants, we determined the occlusal relationship after fixing superstructures in a study cast, on examination of the positions and bearings of inserted implants. We then made up a guide to put it to practical use in the oral cavity, and gained clinically good results. We picked two cases out of the latest implanting data and examined the study cast in occlusal bearing and the post-operative cast in three bearings; (occlusal, buccal and distal). As a result, this method could be considered suitable for measuring the efficiency of the guide. In measuring it, the fact that an inserting position of implant was displaced 1mm (at the maximum) to mesio-distal and about 0.3mm bucally was recognized. Planting direction inclined approximately 4.5° (at the maximum) to mesio-distal and approximately 3° bucally

A Study on the Physical Sensations of Four Kinds of Trial Toothbrushes and Four Different Toothbrushing Methods

Using 65 students of the hygiene school attached to Matsumoto Dental College (35 first-year students, 30 second-year students) as subjects, we performed an investigation into the different physical sensations produced when using 4 trial toothbrushes and 4 different toothbrushing methods. The conclusions are as follows: 1. "Length of brush": There was a tendency to reply that the length of brush seemed slightly shorter when the students brushed with the Roll method, rather than the other three methods. 2. "Stiffness of filaments": There was a tendency to reply that the bristle was much harder when the students brushed with methods from Group B (Methods that primarily use the tip of the bristle) than with methods from Group A (Methods which use the side of the bristle). 3. "Tooth brush wear": A large percentage of students replied that the bristle was more durable when using methods from Group B rather than Group A. 4. "Physical sensation on tooth and gingiva": Brush M and the Open-tufted brush, both classified as "medium" stiffness, were preferred. 5. "Physical sensation of holding the handle": 80-90% of the students, regardless of the toothbrushing method employed, liked the handles of the brushes

Coprecipitation of Aromatic Hydrocarbons from Water with β-Cyclodextrin

Cyclodextrins (CyDs) are cyclic oligosaccharides comprising six, seven, or eight glucopyranose units (called α, β, or γ, respectively) with a central cavity of the corresponding size. It is well-established that CyDs form inclusion complexes with a variety of molecular species (guests) in an aqueous medium. In complexation, both the size (and shape) and hydrophobicity of a guest molecule play important roles. In analytical chemistry, CyDs have been used as modifiers in the solvent xtraction or carriers which　selectively transport certain isomers. We recently found that β-CyD is easily precipitated from aqueous solution upon introducing a cyclohexane vapor into the solution. There is a possibility that, when hydrophobic solutes are present in the aqueous solution, these solutes could be coprecipitated with CyD

カンオン テイコウ コイル オ モチイル サン ト エンキ ノ フロー インジェクション ブンセキ

A flow injection analysis of acid-base by detecting neutralization heat is proposed. A injected sample (acid or base), combined with a carrier (deionized water), was mixed with a reagent (base or acid) stream. A change in the solution temperature was detected by passing the solution, immediately after mixing, through a stainless steel capillary tube around which a thermo-sensitive resistance was coiled. The temperature of carrier was used as a reference Hydrochloric acid solutions of 0.003 to 0.2M could be determined at a rate of 120 smples/h. Using this system, determination in weak-acid and weak-base system could also be performed. Thermo-sensitive resistances used in this work were completely free from corrosion, and effects of the ambient temperature and the sample diffusion in the detector were minimized.中和熱を利用した酸-塩基のフローインジェクション分析法を提唱する。注入された試料（酸または塩基）はキャリア（脱イオン水）によって流され、試薬（塩基または酸）と合流混合される。ミキシング直後の温度変化をステンレスチューブに巻いた感温抵抗体にて検出する。キャリアの温度を参照として用いた。０．００３から０．２Ｍの塩酸溶液を１２０試料／時の速度で定量することが出来た。この方法を用いると弱酸－弱塩基の系でも分析が可能であった。感温抵抗体は腐食から完全に免れており、かつ環境温度の影響や検出部における試料の拡散が低減された

Gastritis Cystica Polyposa-Report of a Case

A case of gastritis cystica polyposa is presented. A 45-year-old woman developed gastritis cystica polyposa at the gastroduodenostomy anastomotic site four years after Billroth II gastrectomy for adenomatous polyp. There was no association of gastric cancer in the lesion