Dentalini use the existing tooth as a base and fit the inlay or onlay onto the tooth. This is done to strengthen the tooth, restore its shape, and prevent further damage.
Both dental inlays and dental onlays are intended to repair the tooth's chewing surface, and shape of the tooth. They are fabricated in the laboratory and therefore take 2 visits to the dentist to complete. Since they are made in the lab, inlays & onlays are generally stronger than direct restorations.