Hajime Miyashita

Long-Term Study of Dental Implants Placed into Alveolar Cleft Sites:

Objective: To evaluate the long-term prognosis of dental implants placed into cleft sites after bone grafting in a relatively large number of cases in order to clarify the usefulness of the modality. Patients: Forty-seven patients with unilateral (dental, n = 32) or bilateral (n = 15) clefts of the alveolar process were included in this study. Interventions: A total of 71 implants, including smooth- or rough-surface titanium, and hydroxyapatite (HA)-coated implants, were placed after bone grafting from the anterior iliac crest and/or mandible. The placed implants were 13 to 15 mm in length. Main outcome: The follow-up period was from 21 to 120 months (average = 60 months). Implant survival rates were calculated as cumulative survival. Marginal bone loss (MBL) from the implant shoulder was examined, with statistical analyses performed on the influence of simultaneous bone graft and surface characteristics. Results: At the end of the clinical follow-up period, all implants except one were in situ and stable. Thus, the overall survival rate was 98.6% at the end of the first year and remained the same until the end of observation. Titanium implants with smooth surfaces had the lowest MBL with almost negligible regression slope, although some implants had relatively high MBL by the end of the first year. Conclusions: Implant therapy in the cleft site offers a reliable option for patients. Particular attention should be focused preoperatively on whether bone volume can provide primary implant stability.

The Incidence of Furca Involvements of Maxillary First Premolar and its Roentgenographic Diagnostic Technique

The diagnosis and the treatment of the furca involvements are clinical entity which require special attention of the periodontists because of its reported poor prognosis. However, the periodontal breakdown involving the furca of maxillary first premolar has been often over looked in daily practice because of the scarcity of information. This study was intended to enhance some practical knowlegde to this field.On 386 periodontal patients, the incidence of furcated maxillary first premolar and the incidence of furca involvements were investigated on the two dental X-ray films one of which having been taken ortho-radially and the other mesio-eccentrically to the maxillary first premolar.Two hundred and twenty-four out of 772 first premolar (29.0%) were interpreted as multirooted. Furca involvement were observed in 26 out of 224 multirooted premolar (11.6%). The incidence of furca involvements of the maxillary first premolar was found 3.3% (26/772×100).Some roentgenographic technique were applied to the furca of maxillary premolar to aid the more reliable roentgenographic interpretation. Computerized tomography was most helpful to determine the configulation of the furca area. Panagram together with the 25°mesio-eccentrically taken dental X-ray film was also helpful.

Clinical Evaluation of Cosmetic and Speech Improvement on Recessed Gingiva by Silicone Gingival Prosthesis.

歯周治療を行った後, 歯肉形態の変化した患者に用いるシリコーン製歯肉エピテーゼの臨床応用を行う目的で, 材料であるシリコーンの組織親和性試験を行った後, 8名の患者への臨床応用を行った。臨床応用の有効性について, 問診による評価および発音障害を強く訴えた1名について発音検査を行った。ラットを用いた埋入実験による組織親和性の判定は対照とした化学重合レジンと比較してシリコーンには組織為害性がほとんど認められなかった。臨床応用については, 審美障害, 発音障害などについて改善が認められ, 特に発音障害を強く訴えていた患者の [S] 音のパラトグラフィー検査および呼気流検査を行った結果, 両検査ともに発音状態の改善が認められた。

Clinical Evaluation on Interdental Stimulating. Interdental Cleaning Efficacy and Reduction of Gingival Inflammation.

我々は先に, 歯間部スティミュレーティングは, 歯間部清掃法として有効であり, また, これを用いた出血診査法は, 歯間部歯肉の炎症の存在を的確に反映することを報告した。さらに, その再現性に関して, 術者が行なう歯肉炎症の簡便診査法としても, 患者自身が行なう歯周疾患に対する自己評価の手段としても, 良好な再現性が得られることを報告した。今回は, 歯間部スティミュレーティングが, 歯間部歯肉の炎症に対してどのような影響を与えるかについて臨床的に検討を行なった。その結果, 歯間部スティミュレーティングをスクラッビング法によるブラッシングに併用することにより, Inter dental Plaque Evaluation, Bleeding on Probing, Probing Pocket Depth, Bleeding on Stimulating. Gingival Index, Gingival Crevicular Fluidの各臨床診査項目において, ブラッシングのみ行なった場合と比べ有意な改善が認められた。これにより, 歯間部スティミュレーテイングは, 歯間部歯肉の炎症を有意に改善することが臨床的に示された。

Rapid diagnosis of periodontitis based on enzymatic activity derived from periodontopathic bacteria. Evaluation of the efficacy of periodontal pocket curettage by SK-013.

本研究の目的は, 歯周病原菌が特異的に産生するペプチダーゼ活性を迅速に測定できる検査薬SK-013 kitを用いて, 歯周ポケット掻爬術の効果判定を行い, その有用性を評価することである。歯周炎患者64名のうち33名を歯周治療群 (T群), 31名を未治療群 (NT群) に分け, 1名につき1歯を被検歯として選択した。T群にはブラッシングによるプラークコントロール (初診時開始) および歯周ポケット掻爬術 (プラークコントロール後4週目) を行いその効果を臨床診査並びにSK-013kitによる酵素活性検査にて評価した (6, 8, 12週目) 。NT群については, 特に歯周治療は行わず初診時および12週目に臨床診査並びに酵素活性検査を行った。その結果, SK-013活性値は, プラークコントロールのみでは変化を示さなかったが, 歯周ポケット掻爬術後, GI, PD, AL, BOPと共に著しく減少した。NT群のSK-013活性は, いずれの検査時においても有意な変化は認められなかった。これらの結果よりSK-013kitによる酵素活性測定法は, 歯周治療効果をモニタリングするのに非常に高い有用性があることが示された。

Introduction of a method of promoting periodontal disease awareness.

In periodontal diseases, due to lack of subjective symptoms, disease awareness and professional consultations are often dismissed even by subjects with already established periodontal lesions. The purpose of this study was to gain data concerning the relationship between bleeding induced by interdental stimulating and some of the clinical indices used in routine periodontal examinations in order to consider if wooden interdental cleaners, which are available to patients themselves, could be used as a means of arousing disease awareness. Furthermore, the buccolingual insertion of interdental cleaners was confirmed together with reconsiderations on its role as a means of proximal plaque control. 180 interdental sites of 30 new out-patients suspected of gingivitis or periodontitis consisted the material. As comparative indices to interdental stimulating, Bleeding on Probing (BOP), Probing Depth (PD), Gingival Index (GI) and Gingival Crevicular Fluid (GCF) measurement were selected. The interdental cleaning efficiency was reconsidered by assessment of interproximal plaque removal. As a result, bleeding was induced both by interdental stimulating and probing in 106 of the 180 experimental sites and was the majority. In relation to PD, concerning pockets less than 1.5 mm, bleeding was not induced by interdental stimulating. 58.8% of 3 mm pockets and all of the pockets deeper than 5 mm bled on interdental stimulating. Concerning the relationship with the GI, no site evaluated GI. 0 bled on interdental stimulating. 12.9% of sites evaluates GI. 1, 73.3% of sites evaluated GI. 2, and all of the sites evaluated GI. 3 bled on interdental stimulating. 39.0% of sites with GCF measurement of 0-21, 51.9% of sites with GCF measurement of 21-40 and 96.8% of sites with GCF measurement of over 81 showed bleeding on interdental stimulating.(ABSTRACT TRUNCATED AT 250 WORDS)

The basic analysis of a friction sound during root planing.

ルートプレーニング終了の客観的指標を求めるために, ルートプレーニング時に発生する擦過音に着目し, 擦過音の変化がどのような際におきるかを検討した。歯石付着面, 歯石付着の見られない面, ルートプレーニング面, 研磨象牙質面の4種歯根面にグレーシータイプキュレットを用いてスケーリングおよびルートプレーニングを行い, 発生した擦過音をソナグラフおよびナロウバンドスペクトラムアナライザーを用いて周波数分析を行った後に操作歯根面のSEM観察を行った。その結果, ルートプレーニング面や研磨象牙面で発生する擦過音では周期性構造をもつ音であったが, 他の2面では周期性構造を持たない雑音様の音であった。また1ストローク中の音の発生にも変化が見られた。本法を更に簡易化することにより, スケーリング, ルートプレーニングの完了の客観的指標の一助となると思われる。

Dimensional Changes of Filament Taken from the Worn-out Tooth Brush

Toothbrushing plays a central role of maintaining a periodontal health so that the design of an adequate tooth-brush has been well established. However, there is no scientific evidence on the durability of the tooth-brush. It is empirically and theoretically accepted that the dimensional changes, especially the decrease in diameter of the filament should result in the decrease in the flexibility of the tufts of tooth-brush and subsequent decrease of efficacy of plaque removal. This study was performed to find the changes in diameter of the filament after the use of given period of weeks.Thirty-eight dental hygienists and 10 dentists were requested to brush with either roll toothbrushing method or horizontal scrub toothbrushing method, with or without dentifrice for 2, 4, 6, 8 and 10 weeks. Multitufted hard tooth-brush with Dupont nylon 612 filament was used as an experimental tooth-brush.The results confirmed that the filament worn out as the period of use became longer. It is especially remarkable at the tip of the filament used with horizontal scrub toothbrushing. On the other hand, roll method decrease the side of the filament as expected, but the extent of wear was comparably lower. The use of dentifrice during toothbrushing enhance the tendency of wear drastically.

Roentgenographic Evidences of Condensing Osteitis Caused by Periodontal Disease

The increased radiopacity of localized areas relating to the dental disease are often encountered in dental roentgenogram. Condensing osteitis is the representative lesion of this kind of radiopaque area.There are several indications suggesting the presence of condensing osteitis caused by the periodontal disease, however, there is no controlled study supporting the scientific evidences of this suggestion.Full mouth dental X-ray films taken from 408 subjects (male 155 & female 253) between the age of 13-76 comprised the material. Condensing osteitis was classified according to the possible etiologic factors. Condensing osteitis was found in 25.7% of the subjects examined. The incidense of condensing osteitis seems to increase as the age become higher. Condensing osteitis was most frequently observed at the mandibular molar area regardless of their etiologic factors. Surprisingly high rate of emergence (34.9%) was observed for the condensing osteitis caused by periodontal disease, on the other hand, the condensing osteitis related to periapical lesion occupied 33.9% of all condensing osteitis. The sujects with condensing osteitis caused by periodontal disease have found to show high alveolar Bone Count indicating higher alveolar bone destruction.

The Influence of Exposed Cementum on the Regeneration of Periodontal Tissue

The clinical influence of exposed cementum is a matter of interest for the periodontist. It may often be speculated that the exposed cementum left in situ during the periodontal flap surgery would affect the healing resulting in an incomplete attachment of the flap, and bring about some unfavourable biological events. However, no controlled experiment has been found out in this respect.In this experiment, the alveolar bone of Rhesus monkeys were chiseled away, and the bone defect with standardized shape and size were created. The copper strip covered by a silk cloth was placed into the bone defect, so that the cementum had been soarked in the artificially produced periodontal pocket for 4 weeks. At the flap surgery with reverse bevel incision, the exposed cementum was curetted away completely in the control group, but it was left unattached and covered by the gingival flap in the experimental group.Sixteen weeks after the surgery, two groups were compared both by the extent of alveolar bone regeneration and by the degree of the new attachment. To evaluate the bone regeneration rate objectively, planometric measurement were made.As the results of the experiment, obvious bone regeneration was observed in the control group, on the other hand, the marked bone destruction was noticed in the experimental group which difference was statistically significant (P<0.05). On the histologic specimens stained by H. E. and Azan-Mallory, no great difference was found between two groups. However, the functional orientation of periodontal fiber was insufficient in the experimental group.The vital and the non-vital tooth (which root canal treatment had been completed) was compared by the same way, but no difference was found histologically and planometrically.It could be concluded that the complete curettement of the exposed cementum is essential f or the more predictable periodontal flap surgery.