THE EFFECT OF THE POLYSTYRENE LINER ON MICROLEAKAGE OF AMALGAM RESTORATION

Polystyrene 이장재가 아말감 변연부 미세누출에 미치는 영향

Amalgam is one of the most commonly used dental restoration material because of its convenience, economic and physical properties. But microleakage in the tooth and amalgam interface has been its major problem, and many efforts have been made to overcome this shortcoming. The purpose of this study is to compare the effect of various liners on microleakage of amalgam restoration. Cavities were prepared on the buccal or lingual surface of ninety sound, extracted human premolars and six different liners (Tubulitec$^{(R)}$, Superbond D-liner II Plus$^{(R)}$, Superbond D-liner II Plus$^{(R)}$ with polymer, Scotchbond Multipurpose Plus$^{(R)}$, Copalite$^{(R)}$, No liner) were unapplied according to manufacturer's instructions and amalgam had been condensed immediately. The specimens were thermocycled by dipping in methylene blue dye at $5^{\circ}C$ and $55^{\circ}C$ for 1500 cycles. The amalgam-tooth interface was examined under stereobinocular microscope and the dye penetration was scored. The results were as follows : 1. The Tubulitec$^{(R)}$ group showed less microleakage than no liner or Copalite$^{(R)}$ group (p<0.01). 2. The Tubulitec$^{(R)}$, Superbond D-liner II Plus$^{(R)}$, Superbond D-liner II Plus$^{(R)}$ with polymer and Scotch bond Multipurpose Plus$^{(R)}$ groups were not significantly different. 3. The Copalite$^{(R)}$ and Scotchbond Multipurpose Plus$^{(R)}$ groups were not significantly different. Using the polystyrene liner and resin liners under admixed type of high-copper amalgam restoration significantly reduced microleakage in the tooth-amalgam interface. Further clinical studies on polystyrene liner are recommended.