Effect of Histological Environment upon Formation of Hard Tissue of the Teeth

In regard to the transplantation of dental pulp the following experiments were carried out using the lower incisors of rabbit: Group 1: removal of hard tissue, leaving the pulp in its natural location. Group 2: transplantation of the pulp into subcutaneous tissue. Group 3: transplantation of the pulp into the anterior chamber of the eyeball. Group 4: transplantation of the pulp into the marrow cavity of the tibia.Results obtained may be summarized as follows:1. Formation of almost normal enamel and dentine was noticed in Group 1 (fig, 3, 4) and occasionally in Groups 3 and 4 (fig. 7, 8), while in Group 2 only formation of osteoid tissue was seen (fig. 5). 2. Formation of the hard tissue of the teeth seems to be dependent on its histological en vironment. When the transplant is surrounded by bony tissue as within the jaw bone or in the marrow cavity, the development of the hard tissue from the transplant and its existence is found to be in a highest degree. In subcutaneous tissue the osteoid tissue once formed is resorbed sooner or later and disappears. The condition in the anterior chamber of the eyeball lies between the two former cases. 3. These observations show that for formation and support of the dental hard tissue the special environmental condition is demanded: It is necessary that the dental pulp should not be exposed to mechanical stimuli. 4. Periodontal and cemental tissue can frequently be noticed to be formed in the margin of the hard tissue originated from the transplant.