Various types of forces are exerted on teeth during movements of mandible and during mastication. These masticatory forces are not always vertical, so some forces may also be exerted on curved or inclined surfaces of tooth. In return tooth counteracts these forces with the help of periodontal ligaments and alveolar bone. Biomechanics of orofacial complex combines engineering and life sciences by applying principles from mechanics to the study of living systems. Biomechanics of dental restorations includes study of measuring the strain and stress in the tooth during and after dental restorations while mastication. The contents of this book are the results of intellectual enjoyment of the development and application of some instruments to research the biomechanics of dental restorations and their forces affecting the orofacial complex.