It is very important to know the effect of cavity configulation on tooth adhesion when attempting clinical success. Polymerization contraction stresses are dependent on the cavity configulations and the stresses dominate the adhesion between the resin and tooth surfaces. C-factor is believed to be representative of the polymerization contraction stress within the cavity. The purpose of this study was to evaluate the relationship between the c-factor and bonding to Class I cavity floor.
Bond strength to Class I cavity floor (C-factor=2 and 3) was approximately 7MPa lower than that to the flat surface of same cavity depth (C-factor=1). As the cavity depth incresed, the bond strenght decreased as well.
It was suggested that the concept of C-factor was, in part, useful to understand the adhesion between the cavity configulation and tooth adhesion. Apparently, the cavity depth was more important factor to lower the bond strenths to Class I cavity floor.

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The adhesiveness between the resin cements and pretreated dentin was studied. As the resin cement, Bistite resin cement (BI), Imperva dual cement (ID), Super-Bond D Liner plus (SB) were used. The polished dentin surface was pretreated with manufacture's instruction, 10T-2, 10T-2+photobond, NPG agent. 10T-2 was self-etching primer containing tannnic acid and FeCl₃, and NPG agent was photocurable bonding agent containing MTYA, GM, glutaraldehyde, and QTX. After the pretreatment, each resin cement was applied on the pretreated dentin surface. The shear bond strengths were measured by universal testing machine after the immersion in 37°C water for 24hr.
The bond strengths according to the manufacture's instruction were 6MPa for BI, 7MPa for ID, and 11MPa for SB. The pretreatment by 10T-2+photobond gave the high bond strength for BI, ID, and SB, but that by NPG agent gave high bond strength for BI.

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This paper introduced a new classification of the dental caries based on the Oral Bacteriology. Drilling and filling decayed teeth were believed the only way of dental caries treatment in Japan for a long time. But recently, the oral bacteriological findings suggested that the dental caries treatment must be considered with bacteriological virulence. The amount of mutans streptococci in saliva has been shown to correlate both with past caries experience and future caries risk. We must be careful for caries risk as same as microlekage on restorative dentistry to prevent the secondary caries. And resin bonding system which can be made a good hybrid layer will protect the dentin from the bacteriological acid. It is also important to make a good hybrid layer for preventing the secondary caries.

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Adhesive metal primer treatments are very useful to gain high bond strengths between metal and resin materials, and to apply through simple procedures. On the other hand, the chemical etching of the denture base resin by surface preparation used with some kinds of organic solvent and alumina air abrasive treatment are effective to improve the repair strengths. In removable partial prosthodontics, both of these are available to manufacture a new denture, to repair a fractured denture and to remodel a treatment denture.
In this report, the following clinical cases used with METALPRIMER, two kinds of solvent and alumina air abrasive are presented.
Case1: Bonding of repair resin material and a plastic teeth to a lingual bar.
Case2: Bonding of repair resin material to a metal cingulum redge rest.
Case3: Occlusal reconstraction by means of the brush on technique of self-curing resin to metal teeth.
Case4: Joining a cast clasp to a full cast crown cemented with adhesive luting agent.
Case5: Remodelling of a removable partial denture by means of joining with a fixed partial denture used with adhesive luting agent.
The further more applications and the other manners may be possible if occasion requires.

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Recently, an adhesion bridge which was the most representative technique in the 1980's adhesive dentistry has not been widely discussed. The reason is thought that all the practicians were clearly divided in two groups, an acceptable group and a non-acceptable one. But the adhesion bridge which needs a only few reduction of sound tooth substance, is the exellent technique for the short span edentulus restoration. To make the adhesion bridge become much more popular, members of the acceptable group planed to introduce in turn their own successful methods, and reconsider the problems. At the start this paper discusses an author's opinion and technique to the adhesion bridge.

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The laminate veneer restoration can be divided into two categories, directly fabricated composite resin veneer and indirectly fabricated acrylic resin veneer or porcelain veneer. There are two methods to make a porcelain laminate veneer: the foil technique and the refractory investment technique. WE examined 231 cases of porcelain laminate veneer restorations on stain, luster, crack, fracture and loosen besides clinical symptoms for periods ranging from 12 to 120 months. 6 cases of crack appeared over one month and 2 cases of pulp necrosis in one week were noted in 48 cases using the foil technique.
No other problems arose with the remaining cases performed with the foil technique nor 183 cases examined through the refractory investment technique cases.

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