This series of in vitro studies consists of four studies, which aimed to deepen knowledge of variables that may affect the load-bearing capacity of a restored tooth, particularly from the perspective of a worn tooth. It was investigated how material selection, cavity design, bonding of the restoration, thickness of the occlusal veneer and cement layer, and water storage influence the fracture load of a restored tooth. The indirect restorative materials used were hybrid ceramic (HC) and lithium disilicate glass ceramic (LDGC). Furthermore, direct particulate-filled resin composites (PFC) and short-fiber-reinforced composite (SFRC) occlusal veneers were studied. The results showed that material selection significantly affected the fracture load of a restored tooth. In general, LDGC was considered favorable compared with HC regarding fracture load. However, HC recorded higher fracture load when used as a thin (0.5 mm) occlusal veneer with a 200 µm thick cement layer. Regarding cavity design, a rounded margin MOD cavity recorded slightly higher fracture load compared with an edge-shaped design. Chamfer preparation, however, had no impact on the fracture load of teeth restored with occlusal veneers. In bonded restorations, tooth fractures occurred, whereas in non-bonded teeth, restorations mainly loosened without tooth fractures. Teeth restored with SFRC occlusal veneers exhibited enhanced fracture load and a more favorable fracture type compared with teeth restored with PFC occlusal veneers. Six months of water storage did not influence the fracture load of teeth restored with direct occlusal veneers in this study setup. It can be concluded that the type of material needs to be carefully considered when restoring a tooth. The studied variables affected the behavior of restored teeth under loading. From the fracture load perspective, minimally invasive methods may be applicable for occlusal restorations in molars.