In this study, we evaluated the clinical performance of partial dental crowns (PIARs), such as overlays and onlays, placed on premolars and molars of adult patients. Premolars are the teeth just behind the canines, and molars are the large teeth at the very back of the mouth. We evaluated a total of 72 restorations in 44 patients, all placed in two private dental practices, and followed them for a minimum of two years. A dental crown is a full cap that covers the entire tooth. The dentist has to grind down the tooth to make space for the crown. It is typically used when a tooth is badly damaged or weakened. A partial restoration, or a partial dental crown (onlay, overlay, inlay), only replaces the part of the tooth that is damaged. By opting for a partial restoration, less healthy tooth structure is removed, making it a more conservative approach. The main goal was to determine whether these restorations remained functional, durable, and whether patients were satisfied with the results over time. Afterward, these restorations were scored by two dental students based on the USPHS criteria. The USPHS system is a checklist used to evaluate the clinical quality of a dental restoration. It assesses different criteria such as how well the edges fit (marginal adaptation), the shape of the tooth (anatomic form), how smooth the surface is (surface texture), whether the edges have dark stains (marginal discoloration), if the color matches the natural teeth (color match), and whether the restoration is still properly in place (retention). Based on the clinical situation, restorations were assigned a score ranging from alpha to charli. The results were promising: after an average of four years, nearly all restorations (97%) were still intact. Patient satisfaction was also very high, with an average rating of 9.8 out of 10. However, some factors influenced the outcomes. Restorations placed on vital (non-root canal-treated) teeth performed better than those on non-vital teeth. Restorations with margins underneath the gumline also showed better clinical success. Additionally, the type of cementation method (conventional cement vs. heated composite) appeared to affect performance. Cementation is the final process of placing the restoration, and the cement functions as both a seal and a bond between the tooth and the restoration. In this study, the most common issue with dental restorations was secondary caries, which is a new cavity forming around or under the restoration. These cases were all seen in the same patient, possibly because they had a higher risk of getting cavities, even though they seemed to take care of their teeth. These cases also used a technique called deep margin elevation (DME), which is employed when a cavity is deep under the gums. While DME makes it easier to place a restoration, it can also be riskier because it is harder to get a perfect seal, and bacteria may get in more easily. We also found that vital teeth (teeth with the nerve still present) scored better than non-vital teeth (teeth with the nerve absent). This could be due to non-vital teeth often lacking large amounts of healthy tooth structure. The study also highlighted that more research is needed to fully understand how different factors influence clinical outcomes. Why is this relevant to society? Dentistry is evolving toward a more conservative, less invasive approach, focusing on preserving as much healthy tooth structure as possible. This study confirms that PIARs offer a reliable and patient-friendly alternative to full crowns, with less tooth reduction and good to excellent short- to mid-term results.