Simple-Challenging-Difficult (SCD) Difficulty Classification for Horizontal Bone Augmentation

To present a novel difficulty classification for horizontal bone augmentation (HBA) grounded in site-specific morphometric characteristics, aiming to assist clinicians in achieving predictable guided bone regeneration (GBR).

HBA is often needed after tooth loss for proper implant placement. GBR is reliable, but success and complexity depend on defect shape. The new Simple-Challenging-Difficult (SCD) classification sorts HBA by defect type and existing bone support: intraosseous defects are within native bone, while extraosseous require regeneration beyond it. Simple cases have horizontal and vertical support; Challenging ones lack horizontal but keep vertical support and need ≤ 4 mm extraosseous augmentation; Difficult defects lack both supports or require > 4 mm extraosseous augmentation.

The SCD classification provides clinicians with a structured approach to assess defect morphology, enabling more accurate treatment planning, better anticipation of potential complications, and improved patient outcomes in horizontal bone regeneration procedures. Clinicians are encouraged to incorporate this classification into their routine assessment protocols to support informed decision-making and to maximize treatment safety and efficacy.

Precise evaluation of defect morphology and quantification of residual osseous support are essential for planning the optimal regenerative technique. The proposed classification system provides a systematic framework to facilitate a more consistent and predictable management of horizontal alveolar ridge augmentation.