Pulp Protection By A Non-Adhesive Smart Restorative Material K. Merte* (1), I. Merte (1), I. Hoyer (2) (Dept. Of Oper. Dentistry And Periodontology, 1: University Of Leipzig, 2: Dept. Of Oper. Dentistry, Depart. Erfurt, University Of Jena, Germany) Recently, a type of smart restorative materials was introduced that does not claim adhesion of the filler-modified resin composite (Ariston pHc) to tooth structure. Instead of a DBS a liner (Ariston Liner) was designed that should permit both the diffusion of anticariogenic ions and the protection of the pulp. The SEM-results of the dentin-liner-interaction pattern and the sealing efficiency were presented at the IADR-meeting 1999, abstract 3404. The conclusion drawn was that the structure of the liner-dentin-interface was quite different from most DBS. The non acid-resistant layer suggested incomplete resin saturation of the demineralized dentin surface. As for protective function and pulpal response, the restorative material was additionally evaluated according to ADA, FDI, and ISO in vivo usage testing guidelines. Non-carious premolar teeth, scheduled for extraction for orthodontic purposes were used. Cavity preparation and restorative procedure were carried out according to the protocoll approved by the Human Ethics Committee (University of Leipzig, 1997). The teeth restored were extracted 7 (10), 28 (8) and 35 (3) days postoperative. As controlls served 4 teeth (2 of them were extracted immediatly after cavity preparation and 2 restored with glass-ionomer cement). Paraffin cuts (7µm) were prepared, stained (HE / Brenn & Brown) and microscopically assessed.   The histologic and histobacteriologic parameters used were: inflammatory cell response (none/acute/chronic/ abscess/infiltrate), odontoblastic layer (regular/irregular/absent), hard tissue formation (yes /no), bacteria within cut dentinal tubules and pulp respectively (absence/presence). Except of intratubular remnants of tags in test teeth there were no significant differences between control and test teeth. No inflammatory cell response was seen which could be attributed to the interaction between the material and the pulpodentin complex. Only in very few cuts bacterial penetration was seen in the outmost layer of the dentinal tubules. Within the limitations of the investigation the liner did not jeopardize the pulp. In ongoing clinical trials restored teeth with postoperative hypersensitivity occured within 1-year recall and in respect to foregoing SEM-results indicating inefficient dentinal sealing by the self-etching liner the material should be optimized to secure long term dentinal sealing and to minimize the risk of microleakage formation. The study was supported by Vivadent (Ellwangen, G).