EFFECT OF DENTIN PREPARATION AND ACID ETCHING ON THE SEALING ABILITY OF GLASS-IONOMER AND COMPOSITE RESIN WHEN USED TO REPAIR FURCATION PERFORATIONS OVER PLASTER OF PARIS BARRIERS

Access openings and furcation perforations were prepared in 60 human e xtracted teeth and randomly divided into four equal groups. Plaster of Paris barriers were created in all perforations. The defects were obt urated using either glass ionomer or composite resin with or without a cid etching of the dentin. The pulp chambers and access openings were filled with composite resin. After immersion in 2% methylene blue solu tion for 2 weeks, the teeth were sectioned longitudinally and dye pene tration was measured under a stereomicroscope using the NIH Image 1.47 Macintosh program. The results indicated that light-cured glass ionom er provided a significantly better seal than did the right-cured compo site resin with or without dentin preparation and acid etching. The gl ass ionomer allowed significantly less dye penetration when used on et ched dentin than it did on nonetched dentin.