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Osteoporosis is considered a risk factor for osseointegration during implant treatment. Photofunctionalization of titanium has been shown to improve bone-based cell adhesion, proliferation, and functional expression, increasing the bone-implant contact rate and bone-implant integration strength. This study aimed to test the hypothesis that photofunctionalization is effective for implant fixation using an osteoporosis rat model. In the biomechanical push-in test, the bone-implant integration strength of the photofunctionalization treatment group was 1.53 times that of the control group (p0.05). These values implied that photofunctionalization restored the ovariectomy-induced low bone-implant integration strength to normal states. In the micro-CT analysis, the BV/TV of the photofunctionalization treatment group was 1.32 times that of the control group (p0.05). These values implied that photofunctionalization restored the ovariectomy-induced low peri-implant bone formation to normal states. These results indicate that photofunctionalization treatment increased peri-implant bone formation and bone-implant integration strength in ovariectomized rats.

Studies examining the effect of operator experience on the accuracy of static guided implant surgery have used postoperative computed tomography (CT) images to measure the error, with inconsistent results. The purpose of this study was to try to clarify this issue by using a measurement method based on the postoperative optical scan. Thirty dentists were divided into an experienced group and an inexperienced group. On a partially edentulous mandibular model in the manikin head, each dentist placed three implants via the stereolithographic (SLA) surgical guide. The implant positions were identified by a desktop scanner and compared with the planned positions using a metrology software program. No statistically significant differences were observed for any of the measured positional and angular deviations of the three implant sites between experienced and inexperienced operators (p &gt, 0.01). All the mean values of deviations of the inexperienced group, except the depth deviation, were less than the experienced group. Implants inserted by dentists under 40 years old had significantly better accuracy than senior doctors in the global deviation at implant apex (p = 0.006). Within the limits of this study, we concluded that operator experience is not a critical factor in achieving the accuracy of guided implant surgery via the tooth-supported SLA surgical guide. Large deviations could occur even with the aid of the SLA surgical guide, and care must be taken to avoid errors for both experienced and inexperienced operators.

A distal free-end situation could result in insufficient stability of the surgical guide, and could reduce accuracy of the static guided implant surgery (sGIS). The purpose of this study was to investigate the accuracy of sGIS using a combination tooth-and-bone supported stereolithographic (SLA) surgical guide in distal extension situation. Thirty dentists, each placed three implants at the Federal Dentaire Internationale (FDI) teeth positions #46, #47 (a distal extension situation), and #36 (a single tooth gap) via the surgical guide on a model fixed to a manikin. Pre- and post-operative computed tomography (CT) images of the models were superimposed, and the positional and angular deviations of the implants were measured with metrology software. An analysis of variance (ANOVA) test was performed to evaluate the intergroup differences. No significant differences were found for all the positional and angular deviations among the three implant sites, except the bucco-lingual deviation at the implant platform in the #47 position (0.43 &plusmn, 0.19 mm) that was significantly larger than the #46 (0.21 &plusmn, 0.14 mm) and #36 (0.24 &plusmn, 0.25 mm) positions (p &lt, 0.0001). Within the limits of this study, we conclude that, in distal extension situation of missing mandibular molars, adding a bone-supported strut in the distal part of the surgical guide can be beneficial to the accuracy of the sGIS.

目的：試作したCAD/CAM用ハイブリッドレジンブロックの臨床的な有効性を評価することを目的とした．方法：ハイブリッド型硬質レジンを加圧，加熱重合し，歯科用CAD/CAMシステムの加工用ブロックサイズに成型加工した．患者36名（女性29名，男性7名）の小臼歯43本，大臼歯8本，合計51本に対しハイブリッドレジンブロックから製作したジャケットクラウンを製作し，6ヶ月から12ヶ月後，平均9.6ヶ月における臨床的評価を行った．評価項目は，辺縁適合性，表面性状，咬耗，破折，クラック，着色，プラークの付着，周囲歯肉の炎症，対合歯の咬耗の9項目とした．結果：15.7％（8症例）において，咬合面の一部に光沢の消失が認められ，5.9％（3症例）において，クラウン表面の一部に着色が認められた．また，装着後1～3ヶ月で4症例について脱離が認められたが，クラウンのクラックや破折は認められず，再装着を行い，その後は問題なく経過している．他の評価項目については装着時と変化は認められなかった．結論：ハイブリッドレジンブロックを材料に歯科用CAD/CAMシステムを用いて製作したジャケットクラウン51本を装着し，平均9.6カ月の予後観察を行ったところ，一部に光沢の消失と着色が認められたが，他には問題はなく，クラウンの材料として有効であることが示唆された．

症例の概要：60歳女性が義歯の違和感と審美障害を主訴に来院した．上顎の欠損部にはインプラント支台の固定性上部構造を装着し，下顎両側遊離端欠損部にはインプラント支台の磁性アタッチメントを用いた可撤性上部構造を装着した．考察：定期的なメインテナンスにおいてインプラントの動揺や骨吸収などは観察されず，経過良好であり，患者が満足する機能および審美性の改善が得られた．またインプラントによる咬合支持が確保できたことで，上下顎残存歯も経過良好である．結論：上下顎多数歯欠損の補綴治療においてインプラント補綴により患者の高い満足度が得られた．

The corrosion and tarnish behaviors of three Ag-based alloys (Ag-Pd-Cu-Au alloy, Ag-In alloy, and Ag-Sn-Zn alloy) in polyvinylpyrrolidone iodine (povidone-iodine) solution were examined. The degree of tarnish was evaluated by visible-ray spectrocolorimetry. Corrosion potential measurements and analyses of corrosion products by X-ray diffractometry were carried out to elucidate the corrosion mechanism. The corrosion rate of the three Ag-based alloys in povidone-iodine solution at its practical concentration used as a gargle solution was so fast that the alloys tarnished within 10 seconds of immersion with the formation of AgI. Thermodynamic consideration and the results of surface analysis by X-ray diffractometry revealed that the main anodic and cathodic reactions were Ag + I(-)--AgI + e- and I2 + 2e(-)--2I- respectively.

This study evaluated experimental abutment forms utilizing adhesion for clinical treatment by the three-dimensional finite element method. Three experimental abutment forms with no axial wall were evaluated: Form 1 was the occlusal surface reduced by 1.5 mm, Forms 2 and 3 were the crown cut perpendicular to the tooth axis 2 mm or 4 mm from the central groove. The restorations were made of 3 types of materials: composite resin, porcelain, and a gold-based alloy. Restorations were bonded to the abutments with an adhesive resin. A vertical load of 500 N was applied to the center of the inner incline of the buccal cusp. The stresses in the adhesives were largest in Form 1 with composite resin and in Form 3. It was indicated that the stresses were greatly affected by the form of the abutment and the restorative materials.