NANDAN Bone Quality Classification (NBQC): A CBCT-based Functional Bone Assessment System for Dental Implantology

Abstract

Background: Accurate assessment of alveolar bone quality is fundamental to achieving predictable outcomes in implant-supported prosthodontics. Existing classifications are largely subjective or rely on single-parameter density assessment, limiting their clinical utility.

Purpose: To develop and validate a novel cone-beam computed tomography (CBCT)-based, multi-parameter bone quality classification system—the Nandan Bone Quality Classification (NBQC)—that integrates radiographic, structural, and functional parameters relevant to implant prosthodontics.

Materials and Methods: The NBQC system incorporates five mandatory parameters: CBCT-derived mean Hounsfield Unit (HU) values, cortical plate thickness, trabecular architecture, anticipated primary stability, and recommended loading protocol. Alveolar bone was categorized into five classes (NBQC-A through NBQC-E). A pilot validation study analyzed 25 implant sites in 18 patients, correlating NBQC classes with insertion torque and Implant Stability Quotient (ISQ) values. An optional Functional Stability Index (FSI; 0–10 scale) was developed for quantitative assessment.

Results: NBQC classes showed progressive correlation with primary stability parameters. Mean insertion torque and ISQ values decreased significantly from NBQC-A to NBQC-E (P < 0.05). Higher classes (A and B) demonstrated excellent primary stability suitable for immediate/early loading, while lower classes required delayed protocols. No implant failures occurred during the observation period.

Conclusions: The NBQC offers a comprehensive, function-oriented classification system tailored for implant prosthodontics. Its quantitative nature, clinical relevance, and compatibility with digital workflows make it promising for both clinical decision-making and research applications.