Considerations for long-term clinical performance of partial restorations: exploring the pathway to success

Restorative dentistry has evolved significantly, emphasizing the importance of partial restorations in preserving natural tooth structure. Advances in adhesive systems play a pivotal role in extending their longevity and promoting minimally invasive dentistry. The second chapter of the thesis, a systematic review, revealed that intracoronal gold restorations outperform indirect resin composites, while lithium disilicate shows promise as a dental material. Laboratory studies on direct composite and lithium disilicate partial restorations in chapters 3, 4, and 5 show good results, which argue for minimal invasive preparation. The use of immediate dentin sealing improves the fracture strength of the restorations. The clinical studies included in this thesis report long-term follow-up.

A retrospective clinical study in chapter 6, spanning 15 years, highlights the remarkable longevity of extensive direct resin composite restorations after replacing amalgams. A long-term randomized clinical trial in chapter 7 showcases the suitability of both direct and indirect resin composites for restoring maxillary premolars with cusp-replacing restorations. Chapter 8 focuses on long-term partial indirect lithium disilicate restorations, exhibiting excellent clinical survival over 7.5 years, with specific patient factors impacting their longevity. Chapter 9 highlights the medium-term clinical excellence of indirect lithium disilicate restorations, where no influence of preparation characteristics on the survival and success of the restorations was seen. Chapter 10 discusses the individual chapters, the connections, and correlations between the studies, as well as the limitations in the aforementioned chapters. Additionally, recommendations for future research were made, and some considerations for the daily application of partial restorations were formulated.