The microscopic pattern of tetracycline fluorescence in the cementum of human teeth.

Ultraviolet microscopy of longitudinal non-decalcified sections revealed fluorescence characteristic of in vivo tetracycline deposition in the cementum of 55 out of 378 human permanent teeth. Patterns of fluorescence could be related to various stages in root development and to pathological events, as well as to the approximate duration of drug intake. Cementum lines formed during apposition of primary root dentin were associated with dentin bands and met the latter at the cemento-dentinal junction: other lines corresponded to incremental cementum apposition after completion of the root. Label was also visualized in localized areas of cementum hyperplasia and in repaired resorption lacunae. Discontinuities in broad fluorescent lines at or near the cementum surface were related to lack of connective tissue attachment when drug exposure occurred, or with subsequent root caries. Observations suggest that typical short, single periods of antibiotic therapy are recorded in the cementum, although marginally or close to the limit of resolution in some cases. Longer, chronic administration or multiple short regimens closely spaced in time are clearly registered. Study of these patterns may be useful in clinical periodontal research.