jkap The Journal of Korean Academy of Prosthodontics J Korean Acad Prosthodont 0301-2875 2005-3789 The Korean Academy of Prosthodontics 10.4047/jkap.2008.46.5.490 jkap-46-490 ORIGINAL ARTICLE Surface characteristics and stability of implants treated with alkali and heat SongYun-SeokDDS1 ChoIn-HoMSD, DDS, PhD2 Graduate student, Department of Prosthodontics, College of Dentistry, Dankook University, Korea Professor, Department of Prosthodontics, College of Dentistry, Dankook University, Korea Corresponding Author: In-Ho Cho Department of Prosthodontics, College of Dentistry, Dankook University, San 7-1, Shinboo-Dong, Cheonan, Choongnam, 330-716, Korea Tel.: +82 41 550 1971 E-mail: cho8511@dku.edu 12 2008 ∗ 12 2008 46 5 490 499 13052008 15072008 29082008 Copyright © 2008 The Korean Academy of Prosthodontics 2008 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Statement of problem

Bioactive materials must have the ability to spontaneously form a bone like apatite layer on their surface and induce direct biochemical bonding to bone. A simple chemical treatment via alkali and heat has been revealed to induce bioactivity in titanium.

 Purpose

The purpose of this study was to evaluate the surface characteristics and stability of alkali and heat treated implants.

 Material and methods

Specimens were divided into three groups; group 1 was the control group with machined surface implants, groups 2 and 3 were treated with alkali solutions and heat treated in the atmosphere and vacuum conditions respectively. The surface characteristics were observed with FESEM, XPS, TF-XRD and AFM. Stability was evaluated with the resonance frequency analysis, periotest and removal torque values. One-way ANOVA and Duncan test were used for statistical analysis.

 Results

1. Groups treated with alkali and heat showed similar characteristics. Groups 2 and 3 showed high compositions of Na ions on the surface with sub-micron sized pores compared to group 1. Group 2 showed mixed compositions of anatase and rutile with superior contents of rutile. 2. Resonance frequency analysis : The ISQ of group 2 showed significantly higher values than that of groups 1 and 3 at 12 weeks. The ISQ of groups 1 and 2 showed significant increase after 4 weeks, and the ISQ of group 3 increased significantly after 2 and 4 weeks respectively (P < .05). 3. Periotest: The PTV of groups 1 and 2 showed significant decrease after 4 weeks, and the PTV of group 3 showed significant decrease after 2 and 4 weeks respectively (P < .05). 4. Removal torque analysis: The removal torque value of group 2 was significantly higher than those of groups 1 and 3 at 2, 4 and 8 weeks. The removal torque values of groups 1 and 3 showed increase at 4 and 12 weeks, but the removal torque value of group 2 showed increase after 4 weeks (P < .05).

 Conclusion

An oxide layer with appropriate crystal structure and amorphous sodium titanate layer can be obtained on titanium implants through alkali and heat treatment in the atmosphere, and even alkali and heat treatment in vacuum conditions, provided a bioactive surface containing sodium. These surface layers can be considered to be effective for enhancement of osseointegration and reduction of healing period for implant treatment. (J Kor Acad Prosthodont 2008;46:490-9).

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Experimental implant specimens.

Fixture installation.

FESEM (S-4100 CS, Hitachi Co., Tokyo, Japan) images of groups 1 (above), 2 (middle), and 3 (below).

X-ray photoelectron spectra of the specimens.

TF-XRD patterns of the surfaces of alkali and heat treated titanium.

AFM (EasyScan E-AFM, Nano-Surf Co., Liestal, Switzerland) images of each specimen.

Sa and Sq values of each group.

Resonance frequency values (ISQ) of each group.

Periotest values of each group.

Removal torque values (Ncm) of each group.

Preparation of experimental groups

Group Preparation Remark N
1 Machined Control 40
2 Alkali + 600℃ heat treatment in atmosphere Alkali/Heat in atmosphere 40
3 Alkali + 600℃ heat treatment in vacuum Alkali/Heat in Vacuum 40