A two-step hydrothermal method for micro/nanotextured titanium implants and their integration outcomes in goat mandible

A crucial aspect of contemporary dental implant research is modifying implant microdesign to achieve early and robust osseointegration. This study describes a new facile subtraction approach for microdesign modification of titanium implants using akali-hydrothermal followed by ion-exchange reaction (AHIE) in a salt solution, and compares osseointegration performance to machined titanium alloy (negative control) implants. The morphology, wettability, and roughness of the implant surfaces were evaluated. Twenty-four cylinders (two types/side) were inserted into the right and left mandibles of six Bengal goats in opposite order. The implant-bone interface was examined at 8 and 16 weeks following implantation using radiography, micro-computed tomography, histology, and scanning electron microscopy. After AHIE treatment, average surface roughness increased marginally (<i>p</i> &gt; 0.05) due to predominantly micron-scale with random nano-scale alterations, whereas wettability improved substantially (<i>p</i> &lt; 0.05). In addition to micro/nano-scale defects, the AHIE treatment produced few honeycomb-like surface patterns. The AHIE implants demonstrated early and direct bone to implant body contact, and achieved stronger bone fixation in vivo than machined implants. Based on laboratory and in vivo data, we conclude that AHIE processing of titanium implants may be a promising technique for improving surface quality while assuring secure and effective osseointegration for dental implant.

当代口腔种植研究的核心方向之一，是通过改良种植体微结构设计，实现早期且稳固的骨整合（osseointegration）。本研究开发了一种简便的减法改性工艺，用于钛种植体的微结构设计改良：先通过碱水热法处理，再于盐溶液中开展离子交换反应（alkali-hydrothermal followed by ion-exchange reaction, AHIE），并将该工艺制备的种植体与机加工钛合金种植体（阴性对照）的骨整合性能进行对比。研究对种植体表面的形貌、润湿性与粗糙度进行了表征。将24个种植体圆柱（分2种类型，每侧各1种）按反向顺序植入6只孟加拉山羊的左右下颌骨内。于种植术后8周和16周，采用放射成像、显微计算机断层扫描（micro-computed tomography）、组织学及扫描电子显微镜（scanning electron microscopy）对种植体-骨界面进行检测分析。经AHIE工艺处理后，种植体的平均表面粗糙度仅小幅升高（P＞0.05），表面形貌以微米级结构为主，伴随随机纳米级变化；而表面润湿性则得到显著改善（P＜0.05）。除微/纳米级结构变化外，AHIE处理还在种植体表面形成了少量蜂窝状形貌。体内实验结果表明，AHIE处理的种植体可实现早期直接骨-种植体接触，且其体内骨固定强度优于机加工种植体。综合实验室表征与体内实验数据，本研究认为：采用AHIE工艺对钛种植体进行表面改性，有望成为一种兼顾优异表面质量与可靠高效骨整合效果的口腔种植体制备技术。