Jun Ishikawa

Clinical Study of Local Factors causing Vertical Bone Resorption

The pattern of bone destruction in periodontal disease is classified to horizontal and vertical bone resorption.To explain the causes of vertical bone resorption, various theories have been proposed and they may be classified as follows:1) Occlusal traumatism with local irritation2) Food impactionHowever, detailed process of vertical bone resorption by those individual factors has not been clarified yet.The purpose of this study is to get fundamental facts of vertical bone resorption. For this clinical examination, 21 patients with 51 vertical bone resorption were examined. The sites were limited in molar areas and front teeth were excluded.As the result of this study, the following conclusions were observed.1) The majority (40%) of vertical bone resorption were seen in mesial site of the first molars of the maxilla and mandible.2) Within 51 vertical bone resorptions, 28 (55%) were associated with food impaction, 35 (69%) with traumatic occlusion, and 20 (39%) with both.3) Within of 28 food impaction, 9 (32%) were vertical food impaction and 19 (68%) were lateral food impaction.

The effect of root surface roughness on periodontal reattachment in monkeys. Part I. Clinical and histopathological observation.

歯根の表面粗さがFlapoperation後の付着様式におよぼす影響を観察するために, サル4頭の上下顎臼歯頬側根頬側面88部位を用いて実験を行った。歯肉弁を剥離して一定範囲の骨を削除し, 根面上のセメント質を完全に除去した後, 滑沢にRoot planingする滑沢群と, 粗造化する粗造群とに分けた。実験計画を観察期間が1, 2, 4, 8週となるように組み, 臨床診査を行い, sacrifice後病理組織学的に観察した。その結果,1. 臨床的計測値 (PL. I., G. I., Probing Depth, Probing Attachment Level) は, 実験期間を通じて両群間に有意な差はなかった。2. 病理組織学的観察では, 上皮の根尖側移動は両群間に明確な差はなかった。新生セメント質は, 両群とも術後2週から観察され, 実験部位の最根尖側で最も厚かったが, 粗造群では歯冠側寄りの粗造面の凹部にも形成され, 根面を平滑化していた。なお, 骨再生は術後4週から生じたが, 両群間の差は明確ではなかった。

A study of clinical examination of furcation involvement. III. A clinical examination of lower first molar furcation invlovement by specially designed probe.

本研究の目的は彎曲探針による下顎第1大臼歯根分岐部病変の水平破壊度の診査の有効性を検索することである。計測用に目盛を付与した曲率半径7mmと8m斑の試作探針とネーバース探針 (Hu-Friedy社) を用いて20歯の根分岐部病変を局所麻酔前麻酔後および歯肉弁剥離時にプロービングした。探針を歯面に密着させた状態で歯冠基準点 (歯冠頬面溝と舌面溝の最も咬頭頂寄りの点) から探針先端までの長さを計測した。歯肉弁剥離時には根分岐部骨欠損の水平距離を計測した。その結果, 曲率半径7mmと8mmの探針は局所麻酔をしなくても根分岐部ポケットの頬舌的最深部まで到達すること, 両探針の歯冠基準点から探針先端までの長さと根分岐部骨欠損の水平距離は有意な相関が認められること (p<0.005), これに対してネーバース探針は水平ポケットが深いと歯冠基準点から探針先端までの長さを計測できないことがわかった。

The Effect of Motivation for Tooth Brushing Instruction

The important role of plaque control has been recognized recently. The goal of plaque control is based on a continuous activity by patient himself. It is a main point that dentist gives them propelling power to lead them to the activity; that is “Motivation”. And how to motivate the patient is a great subject.There are many clinical reports of motivation, however it was very hard to find corroborative studies concerning estimation of the effect of motivation for plaque control. H. M. Goldman emphasized the importance of motivation in 1940, and stated that initial preparation combined with tooth brushing is essential to the all patients with periodontal disease. We believe that motivation to all dental patients is indispensable to control plaque thoroughly.The purpose of this experiment is to make clear the effect of motivation in tooth brushing instruction. The patirnts were separated to three groups as follows; 1) Brushing instruction without motivation 2) Motivation with brushing instruction 3) Control. The amount of plaque accumulation was measured before and after the experimental period. To standardize the contents of motivation and tooth brushing instruction for individual patients, a home made cassette tape was prepared and presented on closed circuit TV. Any personal chair side instruction was not given during experimental period. Plaque was stained using liquid of Plak-Lite and was evaluated by U. S. Navy Plaque Index (Modified).

An Electromyographic and Clinical Study of the Influences of Experimental Prematurity on Masticatory System (I)

The purpose of this paper was to study clinical and electromyographic changes of masticatory system associated with experimental prematurity. This experiment was performed on 3 male subjects, age from 26 to 34 years old, and each possessing a natural dentition without any disorder of temporomandibular joint and masticatory muscles. To induce artificial prematurity on their natural dentition, single high occlusal inlay were placed in their lower molar. Before and after setting inlays, they were investigated electromyographically and clinically.Immediately after placing of inlay, all subjects experienced bruxism such as clenching and grinding, either consciously or even inconsciously. After three days of experimental period, inlays were removed and all of them showed glittered attritional surface. Electromyographically activity of masseter and temporal muscles were inhibited during chewing (peanut), particularly on experimental side. It seems that the musclar inhibition may be a protective reaction to protect the prematufy tooth from excessive forces.

A Survey of Clinical Signs and Symptoms of Mouth Breathing in School Children (Part I).

Mouth breathing is an important etiological factor of chronic gingivitis and marginal periodontitis as well as dental plaque and calculus. The purpose of this study is to demonstrate (a) the frequency of clinical signs of mouth breathing in school children (b) correlation between 8 individual signs (c) relationship between prevelance of gingivitis (PMA Index) and clinical signs and symptoms of mouth breathing (d) relationship between oral hygiene status (OHI) and each clinical signs. The materials were examined, 1) lipseal insufficiency 2) lipdrying 3) over jet 4) open bite 5) mouth breathing line 6) tension ridge of palatal and lingual surface 7) hypertrophy of tonsils 8) lack of uvular reflex. As the result of this investigation, the followings were concluded. 1) Lip-seal insufficiency, mouth breathing line, hypertrophy of tonsils and lack of uvular reflex were found in more than 50% of children. 2) Lip-seal insufficiency, lip drying, over jet, mouth breathing line and tension ridge were related each other respectively. 3) Excepting hypertrophy of tonsils and lack of uvular reflex, all other signs were individually related to both of OHI and PMA.

A Survey of Clinical Signs of Mouth Breathing in School Children (Part II)

Gingivitis, dental caries and malocclusion are often seen associated with mouth breathing. The purpose of this study is to reveal relation between mouthbreathing signs and nasal obstruction. Clinical observation was carried out on mouth breathing signs and on nasal obstruction in cases of 136 school children (11-12 years old).(1) Mouthbreathing signs were seen about half of children and correlated with each other except lack of uvular reflex.(2) 50.7% had some nasal and pharyngeal obstruction. 11.0% were nasal respiration stopped at the time examined and 39.7% had nasal and pharyngeal diseases tending to cause stop of nasal respiration.(3) Nasal and pharyngeal obstruction and oral signs of mouthbreathing were related each other. However correlation between lip-seal insufficiency and oral signs of mouthbreathing was seen more closely.

Histopathological Changes upon the Gingival Tissues Associated with Artificially Induced Mouth Breathing in Rats

To induce artificial mouth breathing on experimental animals has extremely been difficult because of its immediate death following nasal sealing treatment, and we could find only an imitating experiment reported by Butcher et al (J. Periodont. 32: 38, 1961). The purpose of this study is to induce absolute mouth breathing in rats and to investigate histopathological changes of their gingival tissues. Thirty six of Wister strain rats were equally divided into control and experimental groups. To induce absolute mouth breathing artificially, the nose of all experimental animals were sutured using thin wire and metallic buttones. After two weeks of experimental period, animals were sacrificed and materials were obtained.Consequently, we could find much more remarkable hyperkeratinization of epithelial layers in the experimental animals than the control. Inf lammatoric changes, however, were found in both groups of animals, but less in control. As the conclusion of this investigation, absolute mouth breathing may induce hyperkeratinization of the epithelial tissues, but does not initiate gingival inflammation following two weeks of experiment.

Oral findings of wild Japanese monkeys

The incidence and severerity of oral diseases in wild Japanese monkeys have never been adequately documented. A group of wild Japanese monkeys (Macaca fuscata fuscata) consisting of forty-nine individuals was captured on Shodoshima island and fed on a natural raw diet in a very large open cage for six months before examination. The forty-nine monkeys examined were classified into four groups in respect to dental age. Group I deciduous dentition (0-1 year) 12 animals Group II mixed dentition (1-5 years) 13 animals Group III permanent dentition (5-9 years) 13 animals Group IV permanent dentition (9-23 years) 11 animals The oral condition of these monkeys was investigated as a part of the general physical examination carried by the Japan Monkey Centre. This paper is a part of the comparative study of the oral condition among wild and artificially fed monkeys and the purpose of comparison is to clarify whether artificially produced food has an etiological role in major dental diseases or not. Both tooth and periodontal tissue examination were carried out in this study. P-M-A index, gingival pocket-depth, tooth mobility, calculus and debris indices, tooth caries and so on were investigated and recorded. To tranquillize the animals, a tranquillizing agent (produced by Shionogi Seiyaku) was given before experiments. The results of this study were as follows: