Different ideas are difficult to test in dental and medical fields because clinical trials on human beings are ethically limited. Many inspiring thoughts are, therefore, frequently ignored, that is, clinicians and researchers in those fields are generally conservative against the new ideas, and are dependent on traditional methods and opinions with long experience histories. However, such thoughts, ignored at present, may prove to be right, becoming major concepts or theories in the future. That is why some different viewpoints need to be reviewed. This book provides new perspectives and attempts in the field of dentistry; prosthodontics and implantology. Five articles discuss different approaches and peculiar ideas in some research areas; methodology in measuring convergence angles of abutment teeth, definition of early loading in implantology, bone responses to modified implant surfaces, and sinus elevation procedures. Those viewpoints should be useful to clinicians and researchers in dental and medical fields, especially for their insights.