Submitted on: 28 December 1998.
Revised on: 29 March 1999.
Accepted on: 16 May 1999.
___________________BMC Oral Health---BMC
Submitted on: 25 June 2010.
Revised on: 08 September 2010.
Accepted on: 05 October 2010.
___________________BMC Oral Health---BMC
Submitted on: 07 January 2002.
Revised on: 04 May 2002.
Accepted on: 04 June 2002.
___________________BMC Oral Health---BMC
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http://reply.papertrans.cn/1/40/3916/3916-35.png
Submitted on: 17 July 2018.
Revised on: 30 August 2018.
Accepted on: 29 September 2018.
___________________BMC Oral Health---BMC