Movements of healthy and periodontally involved teeth measured with laser reflection technique

The laser reflection method of remote measurement was used to register small tooth movements of upper central incisors from a group of subjects with healthy teeth and another group with periodontally involved teeth. The mobility of the healthy maxillary incisors over a period of 24 hours was well within normal limits. Among orthodontically treated and periodontally involved maxillary incisors relapse was larger sagittally than laterally and largest buccally. This tendency was greatest during the first 5 hours and almost reached its maximum after 1 day. These movements were within the limits of mobility but were not always correlated with mobility or the loss of marginal bone. Furthermore, the relapse was not correlated with the magnitude of orthodontic correction. In this respect, the mean buccal relapse was low, however, individual variations were large. The extent of relapse may be related to the varying intensity of parafunctional habits.