Effect of Hygiene Protocols on the Mechanical and Physical Properties of Two 3D-Printed Denture Resins Characterized by Extrinsic Pigmentation as Well as the Mixed Biofilm Formed on the Surface

Abstract

To assess the effect of hygiene protocols and time on the physical–mechanical properties and colony-forming units (CFU) of Candida albicans, Staphylococcus aureus, and Streptococcus mutans on 3D-printed denture resins (SmartPrint and Yller) with extrinsic pigmentation compared to conventional resin (CR). The protocols were evaluated: brushing (B), brushing and immersion in water (W), 0.25% sodium hypochlorite (SH), and 0.15% triclosan (T), simulating 0, 1, 3, and 5 years. The data were analyzed by ANOVA with repeated measurements, ANOVA (Three-way) and Tukey’s post-test, generalized linear model with Bonferroni adjustment, and ANOVA (Two-way) and Tukey’s post-test (α = 0.05). The protocols influenced color (p = 0.036) and Knoop hardness (p < 0.001). Surface roughness was influenced by protocols/resin (p < 0.001) and time/resin (p = 0.001), and flexural strength by time/protocols (p = 0.014). C. albicans showed interactions with all factors (p = 0.033). Staphylococcus aureus was affected by protocols (p < 0.001). Streptococcus mutans exhibited no count for SH and T (p < 0.001). Yller resin showed more color changes. The 3D-printed resins displayed lower microhardness, increased roughness, and decreased flexural strength compared to CR with all protocols in a simulated period of 5 years. The indication of printed resins should be restricted to less than 3 years.

Strategies for Preventing and Treating Oral Mucosal Infections Associated with Removable Dentures: A Scoping Review

“…In addition to the development of products and methods that aim to reduce the microbial load and prevent DRS, technological development also provides new materials for application in the manufacture of prostheses, such as additive manufacturing (printed) and subtractive manufacturing resins. Aiming to evaluate the behavior of these materials in the face of biofilm formation, and their physical–mechanical behavior when exposed to different environmental factors and hygiene protocols, some in vitro studies have been carried out [ 116 , 129 , 130 , 131 , 132 , 149 ].…”

“…In this context, an experimental study observed that the use of brushing combined with 0.25% sodium hypochlorite for 20 min effectively reduced the microbial load of multispecies biofilm. However, they noted that the printed resins experienced alterations in their physical–mechanical properties when evaluated over a simulated period of 5 years [ 149 ]. Consequently, caution is warranted when recommending the prolonged use of these resins.…”

“…Studies that evaluated Candida albicans formation in different types of resins, such as thermopolymerized PMMA/conventional resin, and milled and printed resins, demonstrated greater adhesion, higher counts of colony-forming units, and the formation of Candida albicans hyphae in printed resins compared to conventional and milled resins [ 129 , 131 , 132 ]. Furthermore, as printed resins present physical–mechanical changes compared to conventional resins, it is recommended to use printed resins for the manufacture of denture bases for temporary rehabilitative treatments that are restricted to less than 3 years [ 149 ]. Innovatively, a 3D-printed denture base resin material modified with mesoporous silica nanocarriers loaded with silver in varying proportions (0.0–2.0 wt%) (Ag/MSN) was developed to enhance the mechanical and antimicrobial properties.…”

“…The by-title/abstract screening resulted in the exclusion of 452 articles The full text of the remaining 131 articles was screened, and 104 of them were selected [2 16,18,22-37,40,41,43-45,47,49-88,90,92-116]. Another 38 articles were found in the gra literature, 19 by a senior expert indication [19,39,89,[117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132], and 19 from searchin citations [38,48,[133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148][149], resulting in a total of 142 articles for the scoping review according to the study workflow in Figure 1. Another 21 articles were used to describe th essential definitions in Sections 2.2.1 and 3 [1,17,20,21,42,…”

“…GaA1As diode laser [71,72] Suspension (50 and 100 mg/L-Photogem ® ) [110] Twice a week, with an interval of at least 48 h between sessions, for four weeks. [71,72] 30 min (pre-irradiation solution) and 36 min during irradiation [109] Microwave irradiation Microwave Sterilizer (700 W) [92,129] Once a day (3 min) for 14 days, with a wash-out period of 30 days break 7 days [92] 3 min irradiation [129] Associated * Brushing and Sodium hypochlorite 0.05%, 0.2%, 0.25%, 0.5% [23,26,112,122,123,144,149] 5 and 30 min for 6 weeks [23] Soak 20 min once a week and brush daily for 6 weeks [26] Immersion for 10 min a day for 15 days [122] Brushing three times a day and soaking (20 min) for 14 days with a wash-out period on day 7 [123] Brushing for 1 min, three times a day, and immersion for 10 min, once a week for two weeks [112] Brushing the mucosa and prosthesis for 3 min, three times a day, and immersing the prosthesis for 20 min, once a day, for 10 days [144] 484 h of soaking and 60 months of brushing simulation [149] Table 2. Cont.…”