Submitted on: 24 June 2003.
Revised on: 20 July 2003.
Accepted on: 07 September 2003.
___________________Journal of Advanced Oral Research
Submitted on: 22 June 2002.
Revised on: 25 September 2002.
Accepted on: 07 November 2002.
___________________Journal of Advanced Oral Research
Submitted on: 06 July 2002.
Revised on: 30 September 2002.
Accepted on: 11 November 2002.
___________________Journal of Advanced Oral Research
http://reply.papertrans.cn/2/151/15085/15085-34.png
http://reply.papertrans.cn/2/151/15085/15085-35.png
http://reply.papertrans.cn/2/151/15085/15085-36.png