Z-100

To evaluate surface roughness and bacterial adhesion after in situ biodegradation of the cementation interface of indirect restorations cemented with preheated resin composite.

Resin composite blocks (Z250XT/3M ESPE) were cemented to bovine enamel (7 × 2.5 × 2 mm) using preheated microhybrid resin composites: (1) Filtek Z100 (3M ESPE) (Z100); (2) Gradia Direct X (GC America) (GDX); and (3) Light-cured resin cement RelyX Veneer (3M ESPE) (RXV) (n = 21). The resin composites were preheated on a heating device (HotSet, Technolife) at 69°C for 30 minutes. Disk-shaped specimens (7 x 1.5 mm) were made for biodegradation analysis with the luting agents (n = 25). The in situ phase consisted of 20 volunteers' using an intraoral palatal device for 7 days. Each device had six cylindrical wells for the blocks and the disk-shaped specimens. Biodegradation was evaluated through surface roughness (Ra), scanning electron microscopy (SEM) micromorphological analysis, and colony-forming unit (CFU) count. The film thickness of the luting agents was also measured under stereomicroscopy.

Increased surface roughness was observed after the cariogenic challenge without differences between the luting agents. Higher variation and surface flaws suggestive of particulate detachment were observed for Z100. No differences were observed in CFU counts.

All materials underwent surface biodegradation, and the surface roughness of the resin cements was similar to or lower than that of the preheated resin composites. The resin composites' film thickness was thicker than that of the resin cement. Clinicians should be aware of these factors when choosing the use of preheated resin composite since it can lead to reduced longevity of the cementation interface and, therefore, restorations.

The early socio-economic differences in smoking build on the interplay between individual-, family-, peer-, and school-related factors. The present study aimed to add knowledge to this by examining susceptibility to smoking (S-SM), electronic cigarette (e-cigarette) use (S-EC), and smokeless tobacco (snus) use (S-SN) by educational aspirations in a country with advanced tobacco control policies. National cross-sectional School Health Promotion study survey was conducted among 8.–9. grade students (av. 15-year-olds) in 2017 with no prior smoking (n = 47 589), e-cigarette use (n = 49 382), or snus use (n = 53 335). Gender-stratified, age-adjusted multilevel logistic regression analyses with S-SM, S-EC, and S-SN were considered as outcomes and student- and school-level (aggregated) factors were considered as independent variables. The highest prevalence was observed for S-EC (girls 29%, boys 35%), followed by S-SM (16%, 15%) and S-SN (10%, 16%). Compared to those planning for general upper secondary education, S-SM was the highest for those without educational aspirations (OR = 1.20, 95% CI = 1.04–1.40), S-EC for those planning for vocational education [1.15 (1.05–1.25)], and S-SN for those planning for extra year/discontinuation [1.65 (1.04–2.60)] among girls. Among boys, both S-SM [1.37 (1.23–1.52)] and S-EC [1.19 (1.09–1.29)] were the highest among those planning for vocational education, with no clear associations with S-SN. Current other tobacco/e-cigarette use [OR range 1.27–8.87], positive attitude towards product use in one’s age group [3.55–6.63], and liking school [0.58–0.68] consistently associated with susceptibility. Students not planning for academically oriented education had higher susceptibility to different nicotine products. High S-EC warrants monitoring to strengthen policy evaluation and prevention.