Ultrasound‐based jawbone surface quality evaluation after alveolar ridge preservation

Abstract

BackgroundBone readiness for implant placement is typically evaluated by bone quality/density on 2‐dimensional radiographs and cone beam computed tomography at an arbitrary time between 3 and 6 months after tooth extraction and alveolar ridge preservation (ARP). The aim of this study is to investigate if high‐frequency ultrasound (US) can classify bone readiness in humans, using micro‐CT as a reference standard to obtain bone mineral density (BMD) and bone volume fraction (BVTV) of healed sockets receiving ARP in humans.MethodsA total of 27 bone cores were harvested during the implant surgery from 24 patients who received prior extraction with ARP. US images were taken immediately before the implant surgery at a site co‐registered with the tissue biopsy collection location, made possible with a specially designed guide, and then classified into 3 tiers using B‐mode image criteria (1) favorable, (2) questionable, and (3) unfavorable. Bone mineral density (hydroxyapatite) and BVTV were obtained from micro‐CT as the gold standard.ResultsHydroxyapatite and BVTV were evaluated within the projected US slice plane and thresholded to favorable (>2200 mg/cm3; >0.45 mm3/mm3), questionable (1500–2200 mg/cm3; 0.4–0.45 mm3/mm3), and unfavorable (<1500 mg/cm3; <0.4 mm3/mm3). The present US B‐mode classification inversely scales with BMD. Regression analysis showed a significant relation between US classification and BMD as well as BVTV. T‐test analysis demonstrated a significant correlation between US reader scores and the gold standard. When comparing Tier 1 with the combination of Tier 2 and 3, US achieved a significant group differentiation relative to mean BMD (p = 0.004, true positive 66.7%, false positive 0%, true negative 100%, false negative 33.3%, specificity 100%, sensitivity 66.7%, receiver operating characteristics area under the curve 0.86). Similar results were found between US‐derived tiers and BVTV.ConclusionPreliminary data suggest US could classify jawbone surface quality that correlates with BMD/BVTV and serve as the basis for future development of US‐based socket healing evaluation after ARP.