Effect of chemical treatment on the bioactivity of titanium

Min, Kwan Sik; Lee, Min Ho; Ahn, Seung Geun; Park, Charn Woon

Abstract

STATEMENT OF PROBLEM: Titanium is widely used as an implant material for artificial teeth. Also, studies on surface treatment to form a fine passive film on the surface of commercial titanium or its alloys and improving bioactivity with bone have been carried out. However, there is insufficient data about the biocompatibility of the implant materials in the body. PURPOSE: The purpose of this study was to examine whether the precipitation of apatite on titanium metal is affected by surface modification. MATERIALS AND METHODS: Specimens chemically washed for 2 minute in a 1:1:1.5 (in vol%) mixture of 48% HF, 60% HNO3 and distilled water. Specimens were then chemically treated with a solution containing 97% H2SO4 and 30% H2O2 at 40 degrees C for 1 hour, and subsequently heat-treated at 400 degrees C for 1 hour. All specimens were immersed in the HBSS with pH 7.4 at 36.5 degrees C for 15 days, and the surface were examined with TF-XRD, SEM, EDX and XPS. Also, commercial purity Ti specimens with and without surface treatment were implanted in the abdominal connective tissue of mice for 4 weeks. Conventional aluminium and stainless steel 316L were also implanted for comparison. RESULTS AND CONCLUSIONS: The results obtained were summarized as follows. 1. An amorphous titania gel layer was formed on the titanium surface after the titanium specimen was treated with a H2SO4 and H2O2 solution. The average roughness was 2.175 micrometer after chemical surface treatment. 2. The amorphous titania was subsequently transformed into anatase by heat treatment at 400 degree C for 1 hour. 3. The average thickness of the fibrous capsule surrounding the specimens implanted in the connective tissue was 46.98 micrometer in chemically-treated Ti, and 52.20, 168.65 and 100.95 micrometer, respectively in commercial pure Ti, aluminum and stainless steel 316L without any treatment.