In-vitro influence of the use of an erythritol powder through air polishing on the surface roughness and abrasiveness of various restorative materials.

The aim of this in-vitro study is to compare the prophylaxis powder Airflow® Plus to a conventional prophylaxis paste with regards to surface abrasion and roughness on four different restorative materials. A total of 80 samples were fabricated, including 20 of each investigated material. Among those were a nanocomposite (Ceram X Spectra™ ST, Dentsply), a glass ionomer cement (Ketac Fill™, 3M™), a cast metal alloy (Bio Maingold SG®, Heraeus Kulzer) and a ceramic (HeraCeram® Saphir, Heraeus Kulzer). Of each material, all samples were equally divided into two groups. Samples in one group were treated with AirFlow® Plus using the AirFlow® Prophylaxis Master (EMS, Switzerland) (Group AF) and the ones in the other group with Prophy Paste (Cleanic™, Kerr, Austria) (Group CL) on a rubber cup. Applied force amounted to 1.5 N at 2000 rpm. Under controlled reproduceable conditions, a 10-year interval with 4 application per year, a total of 200 seconds, was simulated. Size of each sample amounted to 6 mm in diameter and 2 mm in height. Half side of each sample were treated. While comparing the treated and untreated area of each sample, surface abrasion and roughness were measured using an optical 3D system. Roughness was measured based on the arithmetic roughness average of the surface (Ra) and root mean square of the surface roughness (Rq). The statistical evaluation of the data was carried out using the non-parametric Mann-Whitney-U-test, Wilcoxon-test and the Kruskal-Wallis test for group comparisons. In conclusion, the use of the rubber cup with Prophy Paste caused a significantly higher abrasion on composite, ceramic and gold compared to the AirFlow® Plus powder (p < 0.05). In group AF, the significant highest values for Ra were determined on GIC, followed by composite, gold and then ceramic in intragroup comparison. Ra on GIC was significantly higher in group AF (p < 0.05)

Effect of 10% fluoride on the remineralization of dentin in situ

ABSTRACT Objective The purpose of this randomized, cross-over, in situ study was to determine the remineralization of demineralized dentin specimens after the application of a 10% fluoride (F-) or a 1% chlorhexidine&#8211;1% thymol (CHX&#8211;thymol) varnish. Material and Methods Twelve individuals without current caries activity wore removable appliances in the lower jaw for a period of four weeks. Each appliance contained four human demineralized dentin specimens fixed on the buccal aspects. The dentin specimens were obtained from the cervical regions of extracted human third molars. After demineralization, half the surface of each specimen was covered with a nail varnish to serve as the reference surface. The dentin specimens were randomly assigned to one of the three groups: F-, CHX&#8211;thymol, and control (no treatment). Before the first treatment period and between the others, there were washout periods of one week. After each treatment phase, the changes in mineral content (vol% µm) and the lesion depths (µm) of the dentin slabs were determined by transverse microradiography (TMR). Data analysis was accomplished by the Kruskal-Wallis test and the Mann-Whitney U test (p<0.05). Results The medians (25th/75th percentile) of integrated mineral loss were 312.70 (203.0-628.7) for chlorhexidine varnish, 309.5 (109.8-665.8) for fluoride varnish, and -346.9 (-128.7 - -596.0) for the control group. The medians (25th/75th percentile) of lesion depth were 13.6 (5.7-34.5) for chlorhexidine varnish, 16.5 (5.6-38.1) for fluoride varnish, and -14.2 (-4.5- -32.9) for the control group. Use of the 10% F- or 1% CHX&#8211;1% thymol varnishes resulted in significantly decreased mineral loss and lesion depth in dentin when compared with the control group. There were no statistically significant differences among the test groups. Conclusions Within the limitations of this study, the results suggest that the effect of the treatment of demineralized dentin with 10% F- or 1% CHX&#8211;1% thymol is better than without any treatment