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Objective The aim of the present study was to evaluate the mechanical and thermal characteristics of two denture base acrylic resins containing silver nanoparticles (AgNPs).Material and Methods Two different acrylic denture base resins (heat-polymerized and microwave polymerized) containing 0.3, 0.8 and 1.6 wt% AgNPs were evaluated for flexural strength, elastic modulus and impact strength. The glass transition temperature (Tg) and relative heat capacity (Cp) of the samples were determined from the Differential Scanning Calorimetry (DSC) results. For statistical analysis, two-way ANOVA and Tukey-HSD tests were performed.Results Addition of 0.8% and 1.6% AgNPs in microwave-polymerized resin significantly decreased the transverse strength and elastic modulus. In terms of impact strength, the addition of AgNPs has no effect on both resin groups. Glass transition temperature (Tg) was decreased with the addition of AgNPs for both denture base resins.Conclusions The incorporation of AgNPs, generally used for antimicrobial efficiency, affected the transverse strength of the denture base acrylic resins depending on the concentration of nanoparticles. Tg was decreased with the addition of AgNPs for both denture base resins.

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Objectives To investigate the association between oral parafunctions, personality traits, anxiety and signs and symptoms of temporomandibular disorders in the adolescents. Methods Two hundred and seventy adolescents were examined clinically for the signs and symptoms of temporomandibular disorders. Participants completed questionnaires about demographic variables, medical history, symptoms of temporomandibular disorders, parafunctional oral habits, Minnesota Multibasic Personality Inventory, and Spielberger State-Trait Anxiety Inventory. Results Logistic regression analyses revealed that bruxism was associated with joint tenderness (Odds ratio (OR)=6.38, p < 0.01), joint noises (OR=6.02, p < 0.01) and masticatory muscle tenderness (OR=4.19, p < 0.05) to palpation. State anxiety showed increased risk of joint tenderness (OR=2.47, p < 0.05) and muscle tenderness (OR=3.25, p < 0.05) to palpation. Conclusion Within the limitations of this study, it was concluded that oral parafunctions, especially bruxism, state anxiety, depression and hysteria were associated with signs and symptoms of temporomandibular disorders in adolescents.

Objective:The objective of this study is the effect of different heat polymerization conditions on the strength of polymethyl methacrylate (PMMA) resin base is unknown. Distinguishing one method that provides improved mechanical properties may be beneficial to the clinical success of complete and partial dentures and overdentures. The purpose of this study was to evaluate the effect of different polymerization methods on the flexural strength of a dental PMMA resin.Materials and Methods:Forty PMMA specimens (64 mm × 10 mm × 4 mm) were prepared with 4 different polymerization methods (n = 10); heat polymerization at 74°C for 9 h, at 100°C for 40 min, and with 620 kPa pressure at 100°C for 20 min. The remaining group of specimens was microwave polymerized at 180 W for 6 min. All specimens were thermocycled at 5°C and 55°C for 5000 times. Three-point flexure test was used to measure the flexural strength of specimens. One-way ANOVA and Tukey Honestly Significant Difference were applied to analyze the differences in flexural strengths (α = 0.05).Results:The flexural strength of heat-polymerized groups was similar. The flexural strength of microwave polymerized group was significantly different and lower than the other groups (P < 0.05).Conclusion:Polymerizing conventional heat-polymerizing PMMA resin with microwave energy resulted in a significant decrease in flexural strength. The results of this study suggest that clinicians may benefit from using heat polymerization when processing PMMA denture bases instead of microvawe polymerization when tested brand is used.

Introduction: Renal amyloidosis may lead to renal disease, and then nephrotic syndrome may develop. To the best of the authors’ knowledge, this is the first case report in which a patient presents with generalized aggressive periodontitis (GAgP) and nephrotic syndrome in conjunction with renal amyloidosis. Case Presentation: An 18‐year‐old male presented to the periodontology department for generalized gingival recessions. He was diagnosed as having primary renal amyloidosis by his physician. The patient presented with severe gingival inflammation and alveolar bone loss. Biochemical tests were within normal limits except for serum albumin level. No amyloid deposition was found in a gingival biopsy, and the patient was diagnosed as having GAgP. Non‐surgical periodontal treatment, in combination with antibiotic treatment, was performed. After 3 years, his systemic and periodontal conditions showed deterioration. Conclusions: The effects of systemic factors related to nephrotic syndrome in conjunction with renal amyloidosis and deterioration in oral hygiene may play a significant role in the progression of periodontal disease. Even if there is no amyloid deposition in periodontal tissues, clinicians should consider that nephrotic syndrome associated with systemic amyloidosis may provide an important contribution to the periodontal breakdown by the modifying conditions that affect the host response to the accumulation of dental biofilm.

The fracture of denture base materials usually occurs due to accidental dropping and mishandling of these materials. Repeated fracture of denture base materials could be a problem for denture materials made of acrylic resins due to lack of toughness of PMMA-based denture materials. Use of a material with higher toughness might eliminate this problem. Properties of heat-polymerized poly(methyl methacrylate) (PMMA) and high-impact polyamide denture base biomaterials were compared. The test results showed that polyamide samples were more resilient and tougher. Polyamide biomaterials might be good candidate as an alternative to denture base PMMA materials for clinical situations of repeated fractures.

The study evaluated the effect of different surface treatments on the surface roughness of a new‐generation fiber‐reinforced CAD‐CAM composite resin (FRC) and its bond strength to veneered composite resin. Fifty specimens (10 mm × 10 mm × 1 mm) were prepared from FRC blocks (Trinia; Shofu) and embedded in acrylic resin. The specimens were divided into five groups (n = 10) for different surface treatments: nontreated (control), Al2O3 airborne particle abrasion, silica coating (Cojet), acid etching (H2SO4) and hydrogen peroxide (H2O2) application. Surface roughness (Ra) of the specimens was measured using a profilometer. A veneering composite resin (3 mm in diameter by 4 mm in length) was applied on the specimens. The shear bond strength between the FRC and the veneering resin was measured. A one‐way analysis of variance was used to analyze the data. The differences among the groups were analyzed with Dunn post hoc tests (α = 0.05). Surface treatments increased the surface roughness, and Al2O3 airborne particle abrasion resulted in the highest Ra value followed by H2SO4, Cojet, H2O2 and control group (P < 0.05). The highest shear bond strength was achieved with Al2O3 application (P < 0.05). Cojet and H2O2 applications resulted in higher shear bond strength than the control (P < 0.05). H2SO4 application resulted in lower bond strength than the control (P < 0.05). Surface treatments increased the surface roughness of FRC. Al2O3 and silica coating increased the surface roughness more than the chemical applications. The tested surface treatments can be used to increase the bond strength except for the H2SO4 application. © 2021 Society of Chemical Industry