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Previous studies have indicated that TiF4 and SnF2 differ in their demineralizing effect when applied topically to root surfaces at the same acidity. The aim of this study was to examine in more detail the outermost layer of root surface specimens by transmission electron microscopy (TEM) after short-term exposure to these acidic fluoride solutions. Root surface specimens were exposed for 1 min and 4 min to equimolar (1.1 M F) solutions of a) TiF4, native pH 1.0; b) SnF2, acidified to pH 1.0; and c) SnF2, native pH 2.5. The specimens were then rinsed in saline and processed for TEM. Exposure to TiF4 resulted in a partly demineralized zone 8-10 microns deep after 1 min and 5-27 microns deep after 4 min of application. A 0.1-micron-thick, electron-dense coating was present in all TiF4-treated specimens. Acidified SnF2 resulted in a completely demineralized zone, 4-7 microns deep, when applied for 1 min and 4 min, whereas SnF2 at native pH produced a 0.5- to 1.0-micron-wide partially demineralized zone. Unevenly distributed crystalline deposits were a frequent finding on SnF2-treated surfaces. The results indicate that solutions of TiF4 and SnF2 at native pH will cause only slight demineralization when applied topically to root surfaces.

Background To better understand and evaluate clinical usefulness of magnetic resonance imaging (MRI) in diagnosis and treatment of temporomandibular disorders (TMD), parameters for the evaluation are useful. Purpose To assess a clinically suitable staging system for evaluation of MRI of the temporomandibular joint (TMJ) and correlate the findings with age and some clinical symptoms of the TMJ. Material and Methods Retrospective analysis of 79 consecutive patients with clinical temporomandibular disorder or diagnosed inflammatory arthritis. Twenty-six healthy volunteers were included as controls. Existing data included TMJ pain, limited mouth opening (<30 mm) and corresponding MRI evaluations of the TMJs. Results The patients with clinical TMD complaints had statistically significantly more anterior disc displacement (ADD), disc deformation, caput flattening, surface destructions, osteophytes, and caput edema diagnosed by MRI compared to the controls. Among the arthritis patients, ADD, effusion, caput flattening, surface destructions, osteophytes, and caput edema were significantly more prevalent compared to the healthy volunteers. In the control group, disc deformation and presence of osteophytes significantly increased with age, and a borderline significance was found for ADD and surface destructions on the condylar head. No statistically significant associations were found between investigated clinical and MRI parameters. Conclusion This study presents a clinically suitable staging system for comparable MRI findings in the TMJs. Our results indicate that some findings are due to age-related degenerative changes rather than pathological changes. Results also show that clinical findings such as pain and limited mouth opening may not be related to changes diagnosed by MRI.

Defined MR criteria that allow for comparative assessment are presented. According to these criteria, a large proportion of the patients referred for MR examination showed morphologic changes indicating TMJ pathology.

The purpose of this study was to evaluate the caries-inhibitory effect of TiF4 as compared with equimolar solutions of neutral and acidified NaF. Sixty Sprague-Dawley rats were weaned 19 days after birth and given a cariogenic diet. They were randomly divided into four groups and given a 1-min topical treatment of the molar teeth on day 1 and day 17 of the experiment with the following solutions: group 1: 1% TiF4, pH 1.5; group 2: 1.3% NaF, pH 7.0; group 3: 1.3% NaF, pH 1.5; and group 4: control, distilled water. From day 2 the rats were inoculated with Streptococcus mutans twice weekly. On day 55 the rats were killed, and caries scored in accordance with Keyes. Total caries scored were (mean +/- SD): group 1, 12.7 +/- 9.5; group 2, 17.4 +/- 8.6; group 3, 14.3 +/- 9.7; and group 4, 29.5 +/- 9.0. There were significantly (p less than 0.05) reduced caries scores for total caries and for buccal + lingual and sulcal areas for all test groups as compared with the control group. Differences between control and test groups in proximal surfaces and between fluoride groups were non-significant. The results showed that the caries-inhibitory effect of TiF4 is at least as good as that of NaF in rats.