The purpose of this study was to determine the antibacterial activity of four dentine adhesive systems, Liner Bond II (Kuraray, LB), Scotchbond Multi-Purpose (3M, SC), Tokuso Light Bond (Tokuso, TO) and Imperva Bond (Shofu, IM) after curing. The cured specimens were made in the mould by applying each primer and adhesive, and placing composite with light irradiation. The bottom surface of the cured specimens was placed on agar plates which were inoculated with Streptococcus mutans, Lactobacillus casei, or Actinomyces viscosus, and the size of inhibitory zone measured after 48h incubation. The results were compared with those obtained from the agar diffusion tests using paper discs containing each component before curing. The extent of curing of each adhesive system was also determined by measurement of the degree of conversion of combined specimens of primer and adhesive, and Knoop Hardness of the cured specimen's surface. Although the almost uncured components produced inhibitory zones, the cured specimens of LB, SC and IM showed no or little inhibition against all bacteria. TO showed inhibitory effect against A. viscosus even after being cured. The extent of curing of TO was the lowest among four specimens. These results indicate that the most of the tested dentine adhesive systems lost antibacterial activity after being cured and that the residual antibacterial activity of TO might be associated with the lower extent of curing seen with this material.

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The purpose of this study is to research the risk factor of the secondary caries with the shedding of restorations. 342 shedding restorations were examined at three dental clinics in Tokyo. Class II metal inlays and core restorations occupiedmajor percentages. Secondary caries were found 61.6% of examined teeth. Statistic analyses were done in 289 shedding restorations. The risk factor of secondary carieses were evaluated intwo-way contignency tables involving the chi-square Test. A personal caries risk, a sort of luting cements, practicians, vital or non vital teeth, a sort of restorative methods were closely related to the risk factor of secondary caries. The fit of cast metal restorations, anterior or posterior teeth, DMF index, sex were not cosiderable as a risk factor. We concluded the most important points to prevent the secondary caries was to reduce the caries risk of patients and to use the resin-bonding material that can be made the hybrid layer.

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More than ten years have passed since resin bonded fixed partial denture was applied to daily clinics. But many of the early resin bonded fixed partial dentures had failed in short time, therefore many dentists do not yet rely on it.
Study of abutment form and retainer design, and also development of adhesive resin which can be maintained in the oral cavity for a longer time have been performed by many researchers and manufacturers. Recently, resin bonded fixed partial dentures perform fairly well in clinic. In order to maintain the resin bonded fixed partial denture for long time in the oral cavity, a proper procedure of adhesive resin is needed and it is very important making a stiff retainer design.
We think that the use of recent adhesive resin which has higher adhesive strength not only to enamel but also to dentin, will increase the clinical cases of resin bonded fixed partial denture.

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This paper evaluated the current situation of resin-bonded fixed partial dentures through long-term clinical trials. There were many debonded prostheses in case of using teeth suffering from periodontal diseases as abutments. The mechanical retention to increase clinical success rates for bonded castings could be achieved with the use of retentive designs employed both proximal and incisal grooves for anterior teeth and wrapping of the retainer arms on the occlusal and chamber preparation for posterior teeth. We have to examine the retentive designs with maximum adhesive area and without interceptive occlusal contacts on the study model. Moreover, better adaptation of resin-bonded fixed partial dentures to abutment teeth and stronger retainers was dependent on the type of casting alloys and laboratory techniques. The availability of adhesive primers for noble metals has simplified the complicated procedures for surface preparation of retainers. The bonding procedures and bond strength of newly adhesive resin luting cements such as Panavia 21 has been improved. Thus, the resin-bonded restorations is capable of withstanding long-term clinical use.

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