症例の概要：患者は80歳の女性，下顎全部床義歯不適合による咀嚼困難を主訴に来院した．下顎両側臼歯部に高度な顎堤吸収を認め，義歯の維持安定を得ることが困難なため，サージカルガイドによるフラップレス手術にて2本のインプラントを埋入し，磁性アタッチメントを用いた

オーバーデンチャーを装着することとした．

考察：磁性アタッチメントの維持力により

オーバーデンチャーの装着直後から義歯の維持安定が向上した．

結論：顎堤吸収が著しい無歯顎患者に対し

オーバーデンチャーは患者の口腔関連Quality of Lifeを改善した．

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Conventional osseointegrated-type implants are considered to require a 3-5 month nonweight-bearing period after implantation. There are few reports regarding mechanical observations of the osseointegration processes of implants, although recently there have been some reports on attempts to reduce the nonweight-bearing period as a result of issues such as esthetics, occlusion, and manducation. Here, we report the results of measurements of initial tooth movement after implantation, and clinical observations of mechanical changes.
The subjects consisted of 63 CAMLOG implants which were grafted at our department from January 2004 to December 2006, and were measured once every week after implantation using a Periotest device. Gingivaformers with 6 mm gingival heights were screwed into the implants, PT values were measured three times at a height of 5 mm using a PT handset, and the average values were calculated.
The average PT value was -3.83 at the time of implant. This value increased to -3.14 after two weeks, then decreased over time to a value of -4.14 after 6 weeks.
Our results show that the PT values of osseointegration implants demonstrate an overall downward tendency. However, there is a period during which PT values temporarily increase and mechanical instability occurs. As PT values are slightly affected by sex, age, and site specificity, it was inferred that it is desirable to reduce nonweight-bearing periods by taking into consideration stability measurements obtained using mechanical test devices such as the Periotest.

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歯科インプラントが臨床応用されてから54 年が経過し，欠損歯の補綴治療として良好な予後が獲得される治療法として周知されてきた．一方，世界の中で最高水準である日本国民の高齢化にとって，口腔機能の維持は，健康へ与える影響も考慮されて重要事項となってきている．そのため，高齢患者が欠損歯補綴治療として歯科インプラント治療を希望することが多くなってきた．高齢者は高齢期以前と比較すると生体機能の老化が進み，特に口腔機能の老化は歯科治療においてさまざまに問題となることが多い．歯科医師は高齢者の歯科インプラント治療を行う上で，必要不可欠な外科的・補綴的対応を行っていくべきである．

また，高齢期以前に歯科インプラント治療を行った患者が，いずれ高齢者になっていることも必然的なことである．そこで，歯科インプラント治療を行う上で，口腔内の経年的変化にも対応できるように補綴治療およびインプラント周囲組織への対応を考慮していかなければならない．

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近年のインプラント治療では審美性，機能性，治療期間の短縮をかね備えなければなら ない． 本症例は59 歳の女性で咬合機能と審美性の回復を希望し，さらに遠方からの来院 のため治療回数と期間の短縮を必要としていた．治療計画は，上顎は義歯の作製，下顎は抜歯と同時に全顎の治療を行うことに決定した．従来の一般的な全顎インプラント治療では，埋入手術中に予定していたインプラント埋入位置に多少のずれが生じ，上部構造が審美的に作製できないことがある． 今回，ノーベルガイドによるサージカルテンプレートを用いた正確な埋入手術により，術前の補綴設計と同じ位置にインプラント即時荷重による埋入が可能になった．さらに所定の位置に補綴が可能になることにより，技工処理上の工夫ができるようになって審美的なインプラント補綴が装着できた． 本治療法により患者は外科的侵襲が少ないことで満足をするばかりでなく，審美性，機能性，治療期間ともに満足して治療を終えることができた．これらの結果から，審美的にインプラント補綴を行うにあたり，本方法は有効な選択肢の１つとなることが示唆された．

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The purpose of this study was to determine whether clinical success can be achieved with immediate loading in the edentulous maxilla and mandible with Brånemark implants (Nobel Biocare, Gotebörg, Sweden) at three years after placement of the implants.
The study sample consisted of 30 patients who were edentulous or about to lose all remaining teeth. A total of 186 implants were placed in 9 maxillae and 22 mandibles, including one bimaxillary patient. One hundred and fifty-four of the 186 implants were immediately loaded and 32 implants were submerged. Five to 7 implants (mean of 5.8 implants) supported the prostheses in the maxilla and 4 or 5 implants (mean of 4.6 implants) in the mandible. All implants immediately loaded were placed in the incisor and premolar regions of both maxilla and mandible. The mean lengths of the implants in the maxillae and mandibles were 14.6±1.8 mm and 16.3±2.3 mm,respectively. All of 52 immediate loaded implants in the maxillae showed placement torque of more than 30 Ncm. Although 5 of 102 implants in the mandibles showed placement torque of 30 Ncm, the remaining implants showed more than 35 Ncm. Provisional implant-supported fixed prostheses were fabricated in a laboratory from an impression and were placed on the next day after the surgery. After 4 to 7 months, definitive prostheses were fabricated and placed. One implant, although still osseointegrated, was removed owing to bone resorption. In the patient, the provisional prosthesis was supported by the remaining 4 implants; thus the cumulative survival rates for implants and prostheses were 99.4% and 100%, respectively, after three years.
This clinical report suggests that immediate loading of implant-supported fixed prostheses in the edentulous maxilla and mandible can be a safe and successful treatment as long as patients are carefully and strictly selected.

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インプラント埋入手術と同時に補綴物を装着するImmediate loading (即時荷重) の有効性を示唆する報告が, 多くなされている. 即時荷重を行うことにより, 免荷期間における患者の審美障害, 咀嚼障害を軽減することができ, 全体の治療期間を短縮することで患者のQOLを向上させることができる. 即時荷重にてインプラント治療を行う場合, 外科処置のみならず, 手術当日の補綴処置が必要とされることとなる. を成功させるためには, 十分な要件を具備したプロビジョナルレストレーションを外科処置後, 迅速に完成し口腔内に装着することが重要となる. また, それを可能とする術前の周到な準備が必要となる. そこで本稿ではインプラント即時荷重時のプロビジョナルレストレーションの製作時の注意と, 実際の製作法についての解説を行った.

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The two implant-retained overdenture (IOD) is a costeffective treatment option for the edentulous mandible.In the early days, an unloaded healing period of 3 months was generally advocated. However, due to the inconvenience of this long healing period, the immediately-loaded IOD has recently been trialed. As one of the most important issues with immediate loading is osseointegration failure due to excessive stress on peri-implant bone during the healing period, the use of magnetic attachments has been considered due to their potential to limit hazardous lateral forces. However, literature regarding immediately-loaded magnetic attachment IODs remains limited, at least in Japan. Furthermore, the advantage of immediately-loaded IODs needs to be demonstrated not only by survival rate, but also by patient-reported outcomes such as oral health-related quality of life (OHRQoL) profiles.
The oral health impact profile (OHIP) is a tool for measuring OHRQoL. Recently described OHIP items represent four dimensions of OHRQoL:Pain;Oral Function;Aesthetic;and Social Psychological Impact. It is believed that these dimensions offer a framework to better understand and measure the impact of oral conditions and the effectiveness of dental interventions. This paper introduces a treatment protocol for immediately-loaded mandibular IODs with magnetic attachments, and an evaluation of treatment outcomes using the new OHIP dimensions.
Two patients treated with immediately-loaded IODs with magnetic attachments were selected from patients who visited the Department of Prosthodontics at Showa University. The chief complaint was inability to chew foods due to denture instability. For both patients, surgery to place two interforaminal implants was planned and performed, then magnetic attachments were delivered immediately postoperatively. No complications have been observed in either patient during follow-up.
OHIP questionnaires measuring frequency of impacts experienced during the previous month were administered to each subject after obtaining informed consent, at baseline, 1 month and 1 year postoperatively. The results showed substantial decreases in OHIP summary scores for both patients (66% and 98% decreases, respectively) at 1 year postoperatively. Four-dimensional analysis revealed that the dimension of Oral Function in both patients was both significantly impaired at baseline and significantly improved with immediately-loaded IODs treatment.
Within the limitations of this small case series, immediately-loaded IODs employing magnetic attachments appear to offer effective treatment resulting in an improved functional component of OHRQoL within a one-month period.

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歯科インプラント治療では，その治療過程にデジタルテクノロジーを応用することが近年さらに注目されている．特に，補綴装置を想定したシミュレーションに基づきインプラント埋入までをガイドするガイデッドサージェリーは，併発症を回避した安全な手術が実現できるだけでなく，補綴装置を考慮した理想的な埋入位置を獲得できる．このデジタルテクノロジーを応用した補綴主導型インプラント治療であるガイデッドサージェリーは，インプラント治療に必須の術式となっている．

ガイデッドサージェリーは静的ガイド法と動的ガイド法がある．サージカルテンプレートを用いて正確なインプラント埋入を実現する静的ガイド法は，さまざまな症例に応用され良好な治療結果を獲得してきた．しかし，サージカルテンプレートを口腔内に装着して行う手術のため，抜歯窩や最後方臼歯部のインプラント埋入などでは正確な埋入が困難な場合もあった．一方，最近登場した3Dナビゲーションシステムを用いた動的ガイド法は，3D情報がリアルタイムにガイドするフリーハンド手術が可能となるため，静的ガイド法では困難であった症例においても正確なインプラント手術を可能とした．

本稿では，インプラント治療に必須の術式となったガイデッドサージェリーの現状と有用性について報告する．さらに，静的ガイド法と動的ガイド法の特長と留意点について，臨床症例を通して解説する．

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The purpose of this study was to evaluate the risk factors for the loss of implants with sinus floor elevation. We statistically carried out a clinical examination on 49 cases, 80 implants at 3 years after the fitting of implant-anchored fixed prostheses.
The results are summarized as follows:
1. Two implants failed in 80 implants, indicating survival rates of 97.5%.
2. There was no statistically significant difference between implant placement timing, initial bone height, sinus membrane thickness, type, diameter, primary stability of implants and graft materials used for sinus floor elevation.
3. The length of implant affected the survival of implants used for sinus floor elevation.

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We are now living in an age where preoperative examinations of oral implants are no longer limited to use of CT data in visual examinations of diagnostic images: through fabrication of computer models, the shape of the jawbone beneath the mucous membrane can also be understood through physical touch. This report uses case studies to present the new methodology and benefits of computerized bone models made with a 3D plaster printer.
The technique was first used in a maxillary sinus floor augmentation procedure. Through the computerized bone model, we were able to understand the unique anatomical features of the patient. Further, because the model was made with plaster material, we were able to very closely simulate the feel of cutting in the actual surgery, enabling pre-surgery selection of implements and precise preparation for the surgical procedure. Next, we used the technique to fabricate provisional restorations for immediate loading in open flap surgery on an edentulous jaw. After connecting the edentulous jaw bone surface, with information gleaned from CT images, with the occlusal surface for the optimally arranged complete dentures, simultaneous fabrication made the previously difficult attachment of the computerized bone model of the edentulous jaw to the articulator possible, and we were able to prefabricate the provisional restorations for the implant.
The examples above show that computer models fabricated through 3D plaster printing make possible safe, reliable, surgical procedures. Further, highly precise fabrication of provisional restorations for prostheses for edentulous jaws is also possible, which clearly shows the notable clinical usefulness of the technique.

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The purpose of this study was to evaluate the risk factors of the loss of osseointegration (late failure) of Brånemark implants (Nobel Biocare, Göteborg, Sweden) with two different surfaces : a relatively smooth machined surface and a rougher surface created by anodic oxidation. We statistically carried out a clinical examination on those implants : 443 implants with a smooth surface and 1,008 implants with a rough surface.
The results are summarized as follows :
1. Seven implants with a smooth surface (1.6%) and five implants with a rough surface (0.5%) lost their osseointegration within one year after the fitting of superstructures. There was a significant difference between them.
2. Age, primary stability and the healing period between implant installation and abutment connection did not affect late failure in the smooth and rough surface implants.
3. In the smooth surface implants, the prognosis of implants of 10 mm or less in length, 5 mm in diameter and installed in the posterior region of the mental foramen in the mandible was significantly poor.
4. In the rough surface implants, the prognosis of implants of 7 mm was significantly poor.

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To investigate whether the surface topography of dental implants affects bone loss around the implants, we installed Brånemark implants with two different surface roughnesses : a smooth machined surface and a rough surface created by anodic oxidation, on an adjacent area in identical patients, and examined marginal bone level radiographically.
The study sample consisted of 21 patients (14 men and 7 women). Sixty implants were installed, 30 with a smooth surface and 30 with a rough surface. Thirty-six implants were submerged, and 24 implants were placed for immediate loading. The marginal bone level was radiographically examined at implant installation, and at 1, 3 and 5 years after installation. The Wilcoxon signedrank test was used to test the significance of marginal bone loss of each surface group.
The difference between the two implant surfaces in marginal bone loss was not statistically significant at 1 year (p=0.796), 3 years (p=0.357) and 5 years (p=0.518) in the submerged group, nor at 1 year (p=0.180), 3 years (p=0.357) and 5 years (p=0.172) in the immediately loaded group. However, there were some cases with large bone loss in rough surfaces associated with peri-implantitis.

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It is important to measure implant stability when evaluating the state of osseointegration and the prognosis of implant treatment. Resonance frequency analysis (RFA) has made it possible to measure the implant stability quotient (ISQ) value at any time during the course of implant treatment.
In this study, implants of differing Youngʼs modulus were placed, and the obtained ISQ value was evaluated.
The following results were obtained.
1. The ISQ value also became large with Young's modulus. However, the ISQ value and Youngʼs modulus closely matched an involution regression curve instead of a straight line with the rise of Youngʼs modulus.
Therefore, the bone-implant-smartpeg (Osstell^TM mentor) system had two modes of behavior. One was a rigid body behavior and the other was a bending behavior.
Rigid body behavior was found for low stiffness (＜5,000 MPa), whereas bending behavior was found for high stiffness (＞5,000 MPa).
This result showed that resonance frequencies in the case of rigid body behavior were more sensitive to changes in bone stiffness than resonance frequencies in the case of bending behavior.
2. In the model of the same Youngʼs modulus, an increase in implant diameter resulted in higher ISQ value.
3. Osstell^TM mentor is suited for following up the stability of an implant, but not to comparing the stability of implants in absolute terms.

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To compare a resonance frequency analyzer and tooth mobility measurement device for the evaluation of dental implant stability, we experimentally installed various implants in vertebral bones of cows and connected abutments. We measured the Implant Stability Quotient (ISQ) calculated from the resonance frequency with Osstell^®; and the periotest value with Periotest^®. The results are summarized as follows:
1. With higher abutment, the periotest value decreased, but ISQ was not affected by abutment connection or the height of abutment.
2. With longer installed implant, both the periotest value and the ISQ increased.
3. With larger diameter of installed implants, the ISQ increased, but the periotest value was not affected by implant diameter.
4. Both the ISQ and the periotest value were affected by the direction of the transducer connection or direction of striking.
5. As the marginal bone level decreased, both the ISQ and the periotest value decreased.
6. Both the ISQ and the periotest value were correlated with the implant placement torque, but the ISQ was more correlated than the periotest value.
This research suggests that resonance frequency analysis with Osstell is useful for the evaluation of dental implant stability.

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A resonance frequency analyzer (Osstell mentor: OSM, Integration Diagnostics) has been developed as a device for evaluating the intraosseous stability of implants.Implant stability quotient (ISQ) values derived from the device are intended to be employed as indices for evaluating intraosseous stability. The aim of this study was to find any changes over time in ISQ values in two-stage dental implants.
Test sites selected included upper jaw anterior implants (UA group), upper posterior implants (UP group), and lower posterior implants (LP group). For ISQ values, we made one measurement from each of the buccal, lingual or palatal, mesial and distal sides.Measurements of ISQ values were made at stage-one surgery (O1), stage-two surgery (O2), superstructure cementation (SC), and one year later (1Y). Items for analysis were 1)reliability of ISQ values, 2)changes of ISQ values over time for each implant site, and 3) relevance of ISQ values at O1 and 1Y.
1. It was revealed that ISQ values increased in reliability as a result of employing the average value of measurements made from 4 directions. 2. In all the groups, changes over time for ISQ values showed similar tendencies. The values increased from O1 to SC, but there was no difference between SC and 1Y. In addition, the LP group marked higher values than the UA and UP groups at all the measurement times. 3. The relation between O1 and the difference between 1Y and O1 was found to be a negative correlation in all groups.
ISQ values measured were found to have high levels of reliability. Changes in ISQ values from O1 to 1Y were revealed. It was also found that the lower the ISQ values at O1, the greater the increase of ISQ values during the test. On the contrary, the higher the ISQ values at O1, the lower the increase of ISQ values during the test.

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無歯顎患者のインプラント埋入に対して，術後管理は困難を伴う．術後，患者から義歯の使用が禁止されることによる摂食障害，粘膜の腫脹による義歯不適合と疼痛，床下粘膜調整材のたびたびの交換および厚みのコントロールなどの切実な訴えを受けた経験も少なくない．今回，残存歯が重度歯周炎で予後に不安が残るため戦略的抜歯を行い，上下顎無歯顎となった患者に上顎は総義歯，下顎は歯肉剥離を行い4 本のインプラントを支台としてブリッジを製作し，即時荷重を行った．そしてプロビジョナルブリッジによる治癒期間を経て，CAD/CAM を適用したチタン削り出しによりワンピースのフレームワークを作製し，補綴した．現在までトラブルもなく5 年間が経過した．このことからも無歯顎に対して支台となるインプラントの数を最小限にした即時荷重コンセプトは臨床的に有用な治療法であることが示唆された．【顎咬合誌33（3）：213-221，2013】

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