1. Division of Oral and Maxillofacial Reconstructive Surgery, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
2. Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
3. Division of Operative Dentistry, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan