Differences in ceramic–bone interface between surface‐active ceramics and resorbable ceramics: A study by scanning and transmission electron microscopy

Abstract

The interface between bioactive ceramics and bone was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The materials were apatite-wollastonite-containing glass ceramic (A-W.GC) as a representative surface-active ceramic, and calcite and beta-tricalcium phosphate (beta-TCP) as resorbable ceramics. Particles of these materials, ranging between about 100 microns and 300 microns in diameter, were implanted into rat tibiae, and specimens were prepared for observation at 8 weeks after implantation. Both SEM and TEM demonstrated that A-W.GC was bonded to bone through a thin Ca-P-rich layer consisting of fine apatite crystals apparently different from those of bone in shape, size, and orientation. Collagen fibers of the bone reached the surface of this layer, and chemical bonding between A-W.GC and the bone was speculated. Calcite and beta-TCP, on the other hand, made direct contact with the bone, and no apatite layer was present at the interface. The surfaces of the implants became rough due to degradation, and bone grew into the finest surface irregularities. However, we were unable to demonstrate any continuity of crystals between the resorbable implants and bone by high-resolution TEM. Accordingly, the bonding strength was considered to be mainly attributable to mechanical interlocking.

Crystalline Bioceramic Materials

“…Consequently, the function of these materials is to participate in the dynamic process of formation and reabsorption that takes place in bone tissues; so they are used like scaffolding or filling spaces allowing to the tissues their infiltration and substitution [111].…”

Numerical osteobonding evaluation of electrically polarized hydroxyapatite ceramics

“…Bioactivity of hydroxyapatite [Ca 5 (PO 4 ) 3 OH; HA] ceramics leads to a direct bonding with live bone tissue without any inclusions 1,2 but is insufficient for various applications in orthopedic and maxillofacial fields, compared with autograft bones. 3 The insufficiency requires an extraordinary accuracy of implant operation for such applications, and these restrict design of HA implant devices.…”

Enhancement of Bone-Like Apatite Forming Abilities of Calcium Phosphate Ceramics in SBF by Autoclaving

“…13 Neo and Kotani et al showed that b-TCP directly bonded to bone intervening no apatite layer by in vivo tests. 4,14,15 On the other hand, Daculsi et al reported formation of carbonate apatite layer in the vicinity of implanted b-TCP. 16 However, connectivity of b-TCP with host bone was reported to be strong in general and attributed to rough surface due to degradation of implanted b-TCP.…”

“…4 The b-HA layer formed on the HA surface is also regarded as one of the important factors for bonding to host bone in vivo. The b-HA formation ability enhanced by the autoclaving was expected to provide the excellent bone-bonding ability to HA and make the strong fixation with bone in vivo.…”

“…[1][2][3] Bone-like hydroxyapatite b-HA layer intervenes between new bone and implanted surface-active ceramics such as HA, Cerabone A-Wଆand Bioglassଆ . 4,5 It was reported that HA bonded to bone directly or via a comparatively thin b-HA layer, and the b-HA layer with about 0.5 mm in thickness intervened between bone and Cerabone AWଆor Bioglassଆ . 5 On the other hand, new bone is directly formed on the surfaces of resorbable ceramics such as b-TCP after implantation in bone.…”