Dentistry & Oral Health

This study is to assess and compare the marginal gap of metal based on onlay and nano resin ceramic (Lava™ Ultimate block) onlay. The study was carried out in vitro on two extracted lower sound human mandibular molars. One extracted tooth was prepared to receive a metal onlay and another one for RNC (Lava TM Ultimate) onlay, which was fabricated using CAD/CAM technology. After fabrication of 12 metal and 12 ceramic onlays, marginal analysis was done under Leica stereomicroscope (Leica, Germany). The gapwidth was measured at 10 defi ned landmarks which include three points on the buccal and lingual surfaces and two points on the mesial and distal surfaces. Mann–Whitney Test was used for statistical analysis (P=0.05). It was observed that overall RNC onlays (Lava™ Ultimate block) showed signifi cant lower marginal gap measured with the exception of the landmark 5 and 6 at disto-lingual site. Landmarks 7 at mid-lingual site showed no signifi cant difference between both groups. It was concluded that, the marginal gap observed were all within the clinically acceptable limit (120 μm). Based on the results obtained, the resin nano ceramic onlays (Lava™ Ultimate block) CAD/CAM can be one of alternative materials for the metal onlay in term of marginal gap.