Abstract:

Traditional classification of fixed dental prosthesis was based on the morphological extent of crown coverage and has played a significant role in the era of standardized restorative dentistry. However, with the widespread adoption of minimally invasive restorative concepts and the increasing prevalence of extensively damaged teeth, the limitations of the original classification—including ambiguous categorization and rigid tooth preparation protocols—have become increasingly evident. This consensus reorients the classification framework toward the biomechanical essence of prosthesis retention, adopting the primary retention form as the principal criterion. Five major types of fixed prostheses for tooth defects are delineated: crown circumferential retention form-dependent, crown box retention form-dependent, pulp chamber box retention form-dependent, adhesive bonding-dependent, and intraradicular retention-dependent prostheses. These types correspond respectively to the following distinct retention mechanisms: circumferential frictional locking, intracoronal box mechanical locking, pulp chamber box mechanical locking, physico-chemical adhesion at the bonding interface, and post-and-core frictional/adhesive retention within the root canal. The external morphology of the prostheses does not serve as an independent classification determinant. This classification system aims to reduce the overlap and ambiguity inherent in the traditional morphological classification, enabling clinicians to select appropriate retention modalities and devise individualized tooth preparation protocols based on remaining tooth structure. It maximizes the preservation of healthy dental tissues while ensuring retention stability and functional restoration, facilitates effective assessment of prosthesis longevity, and provides a reference for clinical practice, education, and academic standardization in fixed prosthodontics for tooth defects.

Key words: classification of fixed prosthesis, retention form, tooth preparation