1. Dental Department; Show Chwan Memorial Hospital; Changhua Taiwan
2. Department of General Dentistry; Chang Gung Memorial Hospital; Taipei Taiwan
3. Department of Prosthodontics; School of Dentistry; University of Alabama at Birmingham; Birmingham AL USA
4. Department of General Dental Sciences; School of Dentistry; University of Alabama at Birmingham; Birmingham AL USA
5. Department of General Dentistry; Chang Gung Memorial Hospital; Chang Gung University; Taipei Taiwan