- Japanese Society for Oral Health
- JOURNAL OF DENTAL HEALTH (ISSN:00232831)
- vol.42, no.1, pp.66-78, 1992-01-30 (Released:2010-10-27)
The effects of the application of various fluorides on the remineralization and fluoride (F) incorporation of root surfaces with or without cementum were evaluated in vitro. Clinincally sound proximal root surfaces of premolars extracted from patients aged 9-14 years were used for experiments and divided into two categories: (1) a dentin group, where cementum was removed by abrasion, and (2) a cementum group, where the cementum was preserved. In both groups, two types of specimens were prepared: (1) sandwich specimens, for assessing mineral volume by a single section technique, and (2) block specimens, for the determination of F incorporation by biopsy.After demineralization by immersion in 0.01M (for sandwiches, pH 5.1, 6mM Ca, 3.6mM P, 1% CMC, 37°C) or 0.1M (for blocks, pH 5.0, 3mM Ca, 1.8mM P, 1% CMC, 37°C) lactate buffer, specimens were treated with one of the following four fluorides during 14-day immersion in remineralizing solution (Rem solution: 3mM Ca, 1.8mM P, 150mM NaCl, 3ppm F, 1% CMC, pH 7.0, 37°C). The fluorides were APF solution (APF), APF gel (FG), F rinse solution (FR) and MFP dentifrice (FD). Control group (immersion in 3ppm F containing Rem solution only) and negative control group (immersion in F free Rem solution only) were also studied. APF and FG were applied for 4 minutes once just before remineralization, and FR and FD were applied for 1 minute every 24-hour remineralizing period. Sandwinch specimens were microradiographed before and after remineralization. The film density of lesions was convereted to aluminum thickness (Ta; μm) and the mineral volume of lesion (Ma; μm·μm) was defined as integrated values of Ta profiles. F content was determined by acid etch biopsy with 0.5M HClO4.The Results were as follows:Remineralization of early root caries lesion in vitro was(1) promoted by the application of fluorides, and accelerated more by the treatment with APF or FG than the treatment with FR or FD, and(2) not significantly different between the cementum and the dentin groups.(3) Cementum had no inhibitory effects on the remineralization of root surfaces.F incorporation in remineralized root surfaces were(1) different between various F treatments, and specimens treated with APF or FG showed significantly higher F uptake level, and(2) greater in the cementum group than that in the dentin group and this fact indicates that cementum would be important tissue for demineralization and remineralization of root sufaces as a source of F ion supply.According to the analysis of correlation coefficient, the degree of remineralization was obviously dependent on F incorporation in lesion surfaces.In conclusion, these findings suggested that F application was effective for the remineralization of root surfaces and F incorporation into root surfaces did not depend on cementum. Thus, professional or self application of fluorides was considered to be higly suitable for the prevention of root caries in the elderly.