Classification of post-and-core assembly failures: An extensive compilation of 33 years of data

Over the past 2 decades, a wide range of post-and-core materials has been developed to restore endodontically treated teeth (ETT) with extensive loss of coronal tooth structure. Although the prognosis and long-term success of ETT are influenced by multiple factors, most research has focused on post-and-core materials, the ferrule effect and luting agents. However, a classification of failures associated with post-and-core assemblies is currently lacking. This study aimed to identify and classify post-and-core assembly failures.A literature search was conducted using the terms "post and core" and "dental post and core" in the title and abstract. Articles published in English between 1991 and 2024 were retrieved from the PubMed®, Scopus and Cochrane Library databases. Of the 491 articles identified, 23 met the inclusion criteria and were used to develop the proposed classification.Based on the available evidence, post-and-core assembly failures can be classified into 2 categories: catastrophic and non-catastrophic failures. To the authors' knowledge, this is the first comprehensive classification of post-and-core assembly failures derived from evidence spanning 33 years of published literature. The proposed classification provides a standardized framework for identifying and reporting failures and may facilitate clinical decision-making, laboratory communication and future research.