ABSTRACT
STATEMENT OF PROBLEM: Posterior composite restorations may be negatively affected by acidic and colored drinks. Little information is available about the effect of acidic drinks on bulk-fill composite resins. PURPOSE: The purpose of this in vitro study was to investigate the effect of acidic drinks on the different properties of conventional and bulk-fill composite resins. MATERIAL AND METHODS: A conventional composite resin and 2 representative bulk-fill composite resins were used to prepare disk-shaped specimens. The degree of conversion (DC) was monitored by spectroscopy (n=5). The specimens were divided into 5 groups: control, artificial saliva, acai juice, red wine, and Coca-Cola and were maintained for 30 days of challenge (3 periods of 15 min/d). Surface topography parameters were measured by interferometry (n=5). Elastic modulus (E) and Vickers hardness (VH) were determined by microhardness dynamic indentation (n=5). Diametral tensile strength (DTS) was determined at 0.5 mm/min (n=5). Shade matching was evaluated by using the Vitapan Classic Shade Guide. The DC, Sa, Ssk, Sku, Sdq, and DTS were statistically analyzed using 2-way ANOVA, followed by the Tukey HSD tests. E and VH were statistically analyzed by 3-way ANOVA, followed by Tukey HSD tests (α=.05). Shade matching was analyzed with the Kruskal-Wallis test. RESULTS: DC values were similar for the immediate evaluation and after 24 hours, regardless of the composite resin (P<.05). All surface topography parameters increased significantly after the acidic drinks and were greatest for Coca-Cola. The E, VH, and DTS decreased significantly for all composite resins tested (P<.05). Acai juice and red wine produced more surface staining than Coca-Cola. CONCLUSIONS: Acidic drinks negatively influenced the physical and mechanical properties of conventional and bulk-fill composite resins.
Subject(s)
Carbonated Beverages , Composite Resins , Elastic Modulus , Hardness , Materials Testing , Surface Properties , Tensile StrengthABSTRACT
Surface treatment alone does not determine the final microtopography of a dental implant, which can be influenced by implant design and the surgical procedure. This study investigated the effect of surgical placement of dental implants with same surface treatments on surface roughness. Three implants (SIN) of each group with different macrogeometries (Strong, Stylus, and Tryon) were analyzed using laser interferometry and scanning electron microscopy to evaluate surface topography. All threaded regions of the implants, namely, top, flank, and valley, were analyzed individually. Relevant surface parameters (S a, S sk, S ku, S tr, and S dq) were calculated for the different regions on each implant before (B) (n = 9) and after (A) (n = 9) placement into porcine rib bones. The behavior and proliferation of a preosteoblastic cell line MC3T3-E1 on titanium surface, cell viability, and osteopontin secretion were evaluated after 24 h, 48 h, and 96 h, also before (n = 18) and after (n = 18) implant placement into porcine ribs bone. As results, the valleys of all implants had an increase in S a values after implant placement. By contrast, the tops of the Stylus A implant and the flanks of the Tryon A implant showed a significant decrease in mean height of the irregularities (S a), 0.16 µm and 1.25 µm, respectively. The Stylus implant presented significantly (p < 0.05) higher asymmetry values on the distribution curve for irregularity heights (S ku) in all regions after insertion into bone (6.99 for tops, 9.54 for flanks, and 17.64 for valleys), indicating a greater preponderance of peaks over valleys. An increase in roughness gradients (S dq) was observed for all macrogeometries after insertion into bone. The cell culture results showed no significant difference (p > 0.05) for all macrogeometries after bone placement. In conclusion, a subtle change in implant surface roughness was detected after insertion into bone for all the macrogeometries, without significantly affecting the cellular parameters studied.
