The procedure involving maximum tooth structure removal is:

Current factors that dictate extension on smooth surfaces include The extent of caries or injury.  The restorative material to be used. Likewise, extension for prevention to include the caries-prone areas on occlusal surfaces has been reduced by treatments that conserve tooth structure. Such treatments may include  enameloplasty, application of pit-and-fissure sealant, and preventive resin or conservative composite restoration. Likewise, the adjacent tooth contour may dictate specific preparation extensions that enable the creation of appropriate proximal restoration form. “Prophylactic odontotomy” procedures were used in the past. These more aggressive procedures involved preparing developmental or structural imperfections of the enamel that were thought to be at increased risk of caries and filling the preparation with amalgam to prevent caries from developing in these sites. Prophylactic odontotomy is no longer advocated as a preventive measure.  Reference: Sturdevant operative dentistry 7th   EDITION, Page No:125