Previous cursory reports of lathyritic aiveoiar bone activity prompted a histotogic and radioautographic investigation of tooth migration patterns in normal and lathyritic mice. Using Sharpey's fiber patterns and the distribution of (^H)-proUne radioactive label as indicators, bone deposition was found on distal, occlusal, and buccal facing alveolar surfaces and revealed normal tooth migration to be in a distal, occlusal, and buccal direction. In addition, the radioautographic label confirmed the reliability of using Sharpey's fiber patterns as directional indicators. Over a forty-day lathyritic period a progressive disturbance of Sharpey/principal fiber attachment at the bone surface plus radioautographic inactivity indicated that the distal and buccal vectors of migration had ceased. However, occlusal migration appeared to continue. These results were considered to be a likely consequence of the duration and severity of the iathyritic change and the difference in turnover times between the supracrestal and periodontai ligament collagen fibers, with further consideration to the occlusion, ultrastructural, and vasailar changes being required.