In this study, we examined the adhesiveness of composite resin to polished enamel and dentin with the mediation of new type of photocurable bonding agents. Two types of of boding agents, DM agent or NPG agent were prepared from the aqueous mixture of methacryloyl tyrosine amide (MTYA), glyceryl methacrylate (GM), QTX which was a water soluble photo initiator.
After the application of DM agent or NPG agent to the polished enamel or dentin, Protect Liner (Kuraray Co., ) or Photobond (Kuraray Co., ) was applied. Then Silux Plus (3M Co., ) was filled and polymerized by the photo irradiation. The tensile bond strength were measured after one day immersion in 37°C water, or after 2000 thermal cycling.
The application of DM agent or NGP agent with Protect Liner showed no adhesion of resin to the polished enamel. The combination Photobond with DM agent or NGP agent gave high bond strengths to polished enamel or dentin. However, the bond strengths to polished enamel by the application of DM agent or NPG agent with Photobond significantly decreased after 2000 thermal cyclings. There were no decrease of bond strengths to dentin by the application of NPG agent with Photobond after thermal cyclings.

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Efficacy of cements on prosthetics either adhesive resin cements (ARC), Superbond C & B and Panavia EX, or zinc phosphate cement (ZPC) was compared in clinics for 13 years at the Okayama University Hospital. The remaking rate due to failure in full coverage crowns except resin jacket crowns cemented with ZPC was 4.5%, on the other hand that cemented with ARC was only 0.97%. The rate was much higher in resin jacket crowns cemented with both ZPC (25.2%) and ARC (10.2%). It was decreased to 4% in adhesion bridge applied for longer than 10 years after improving the design and surface treatments of the retainers. The remaking rate in crowns with resin-core restoration (1%) was lower than that in metal-core cemented with ZPC.

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We had reported that the dental adhesive Panavia 21 had stronger adhesion to dentin which was pretreated with H₃PO₄ and NaCl0.
In this study, we examined a newly designed abutment form that derived the retentive force by adhesion and had no retentive form that utilizes the interlocking force. In this experiment, new abutment form was prepared on extracted human upper premolars. The teeth were treated with H₃PO₄ for 10 seconds and then rinsed and air-dried, and further treated with NaClO for 5 minutes and then rinsed and air-dried. The restorations, cast in Au-Ag-Pd alloy by indirect technique, were sandblasted and tin-plated and then were luted on the abutments with Panavia 21.
The specimens were thermal cycled 0, 10, 000 and 30, 000 times between 4°C and 60°C for 1 minute each or repeatedly stress loaded, 0, 10, 000 and 50, 000 times. Retentive force was measured by universal testing machine (Instron 1000) and microleakage was evaluated by dye penetration test.
The results showed that the new abutment form had higher retentive force than conventional preparation form and had excellent marginal sealing.

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Taking the response of dentin in the butted area into consideration, We examined the application to the dentin margin using adhesive resin cement having a dentin processing system among different cementing agents being used.
As for the adhesive power to the dentin, the dentin processing material was proved to have an effect on many of the applied cases and the power seemed to trend stronger than when only cement was used.
The examination of the penetration of pigments into the crown with a magin set in the dentin of an extracted human tooth found an effect of the dentin processing material on many of the cases as well as the strong adhesive power.
When the abuntment tooth margin of the crown was made of dentin, the adhesive power was stronger and the penetration of pigments was avoided more in cementing with a dentin processing material applied than in cementing only with resin cement used and and we can expect that a clinically better prognosis will be obtained.

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Copalite and Cavity Liner had been used to prevent hypersensitivity and pulp irritation after preparation of teeth for long time. Recently, Pre-Coating technique was introduced for this purpose in dentistry. Imperva Bond (Shofu) was applied to prepared dentin for this technique. The adverse effect of temporary cementation on the bond strength of final cementing materials to the Pre-Coating was investigated. It was found taht temporary cements and moisture decreased the bond strength significantly, and euginol and moisture also decreased the micro-hardness of the Pre-Coating surface. It was concluded that suitable treatment on the Pre-Coating was required before the final cementation to prevent adverse effect of eugenol and moisture on the bonding.

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The stress distribution of resin bonded bridges fabricated by infused aluminous glass ceramic (In-Ceram^®) were investigated by 3-D finite element method. The 3-D finite element model of (1) 2 (3) resin bonded bridge applied on the abutment teeth were simulated. The fracture possibility of ceramic were evaluated by the tensile stress distribution that occurred to the model when load 180 N45° to tooth axis were applied. Loading position were changed to define the severe condition. The extension of wing retainer mesiodistally were investigated.
From the result, it was found that by separately loading at central area of lingual surface in each three tooth and incisal edge of pontic, the maximum tensile stress occurred at the labial surface of connector at gingival side between central and lateral incisor. The highest maximum tensile stress occurred when load were applied at central area of central incisor and at the incisal edge of pontic. By extending the wing to half of mesio-distal width of lingual surface, the maximum tensile stress did not change when compare to the control model that cover the whole lingual surface. On the other hand, the maximum tensile stress of resin bonded bridge with no wing increase 8.2% compare to the control model. Even the highest maximum tensile stress occurred in the resin bonded bridge with no wing, the fracture possibility of the bridge still low compare to the mean tensile strength of In-Ceram^®.

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In case of temporary treatmetn of missing teeth, resin teeth are fixed adhesively to remaining adjacent teeth as pontic using self curing resin. The improvement of adhesion technique in these years has brought longer period service on this prosthesis.
However, the elongation of period in service provoke the serious abrasion of resin teeth, which brought the complete loss of anatomic form. Most effective method to prevent the abrasion is the use of composite resin teeth. However, the labial surface of the tooth is constructed with highly cross-linked ploymer, and it's difficult to achieve the durable bond with adhesives.
In this article, surface treatment of composite resin teeth to achieve the durable bond with self-curing resin adhesives were mentioned and the results of 20, 000 thermocycling test for adhesion specimen were reviewed. Alumina blasting treatment improved the adhesiveness effectively, giving the highest bond strength of above 30 MPa between Superbond C & B and composite teeth. Superbond showed higher bond strength than traditional BPO-amine self curing resin.

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