Comparative clinical evaluation between self-adhesive and conventional bulk-fill composites in class II cavities: A 1-year randomized controlled clinical study.

OBJECTIVE: This randomized controlled clinical trial compared the clinical efficacy of self-adhesive bulk-fill Surefil One with a traditional bulk-fill composite in class II restorations. MATERIALS AND METHODS: Sixty-four direct class II composite restorations were categorized into two groups. Group I, control group (n = 32): cavities were restored by Filtek One bulk-fill composite with Scotchbond Universal (SBU) adhesive in self-etch mode, Group II, test group (n = 32): cavities were restored by Surefil One self-adhesive bulk-fill composite. The study involved a follow-up period of 1 year, during which restorations were assessed at baseline (BL), 6 months, and 12 months using Federation Dentaire Internationale (FDI) criteria. Data analysis was performed using nonparametric tests. A comparison of restoration characteristics was performed utilizing the chi-square test (X2). The significance level was set at 0.05. RESULTS: Filtek One and Surefil One bulk-fill composites revealed clinically acceptable FDI scores over 12-month recalls. Thirty-two patients (64 restorations) were available for all follow-up visits; 100% of the restorations survived. For esthetic properties, Filtek One was far better than Surefil One at all time points. However, in terms of functional and biological properties, both restorations demonstrated comparable performances. CONCLUSIONS: Filtek One bulk-fill restorations were superior in terms of surface luster, surface staining, color match, and translucency, but Surefil One restorations performed well and were similar to Filtek One restorations; however, additional advancements and research are needed to obtain better esthetics. Furthermore, longitudinal studies with extended follow-up periods are needed to assess the clinical potential of both materials. CLINICAL SIGNIFICANCE: Both Filtek One and Surefil One met the FDI criteria, with Filtek One demonstrating superior esthetic and functional qualities and similar performance regarding biological criteria. Both innovative restorative materials show potential for clinical use. Trial registered on ClinicalTrials.gov under registration number; NCT06120868:07/11/2023.

Biomechanical reinforcement by CAD-CAM materials affects stress distributions of posterior composite bridges: 3D finite element analysis.

OBJECTIVES: This 3D finite element analysis study aimed to investigate the effect of reinforcing CAD-CAM bars on stress distribution in various components of a posterior composite bridge. METHODS: A virtual model mimicking the absence of an upper second premolar was created, featuring class II cavity preparations on the proximal surfaces of the adjacent abutment teeth surrounding the edentulous space. Five distinct finite element analysis (FEA) models were generated, each representing a CAD-CAM reinforcing bar material: 3-YTZP (IPS. emax ZirCAD MO; Zr), lithium disilicate (IPS e.max CAD; EX), nano-hybrid resin composite (Grandio Blocs; GB), Fibre-reinforced composite (Trilor; Tri), and polyetheretherketone (PEEK). A veneering resin composite was employed to simulate the replacement of the missing premolar (pontic). In the FEA, an axial force of 600 N and a transverse load of 20 N were applied at the center of the pontic. Subsequently, maximum von Mises (mvM) and maximum principal stresses (σmax) were computed across various components of the generated models. Additionally, shear stresses at the interface between the CAD-CAM bars and the veneering resin composite were determined. RESULTS: CAD-CAM materials with high modulus of elasticity, such as Zr and EX, exhibited the highest mvM stresses and shear stresses while transferring the lowest stress to the veneering resin composite in comparison to other materials. Conversely, PEEK demonstrated the lowest mvM stresses but produced the highest stresses within the veneering resin composite. There was a uniform distribution of mvM stresses in the remaining tooth structure among all groups, except for a noticeable elevation in the molar region of Zr and EX groups. SIGNIFICANCE: Reinforcing CAD-CAM bar materials with a high modulus of elasticity, such as Zr and EX, may result in debonding failures at the connector sites of posterior composite bridges. Conversely, GB, PEEK, and Tri have the potential to cause fracture failures at the connectors rather than debonding.

Bond Strength, Microleakage, Microgaps, and Marginal Adaptation of Self-adhesive Resin Composites to Tooth Substrates with and without Preconditioning with Universal Adhesives.

PURPOSE: This study investigated and compared the bond strengths, microleakage, microgaps, and marginal adaptation of self-adhesive resin composites (SAC) to dentin with or without universal adhesives. MATERIALS AND METHODS: Dentin surfaces of 75 molars were prepared for shear and microtensile bond strength testing (SBS and µTBS). Silicon molds were used to build up direct restorations using the following materials to form 5 groups: 1. Surefil One; 2. Prime&Bond active Universal Adhesive + Surefil One; 3. Vertise Flow; 4. OptiBond Universal + Vertise Flow; 5. Scotchbond Universal + Filtek Z500 (control group). Bonded specimens were thermocycled 10,000x before being tested either for SBS or µTBS using a universal testing machine at a crosshead speed of 0.5 mm/min. Direct mesial and distal class-II cavities were created on 100 sound premolars, with the gingival margin of distal cavities placed below CEJ and restored according to the five groups. After thermocycling, microleakage scores were assessed following immersion of restored premolars in 2% methylene blue dye for 24 h, while marginal gaps and adaptation percentages were investigated on epoxy resin replicas under SEM at magnifications of 2000X and 200X, respectively. Results were statistically analyzed with parametric and non-parametric tests as applicable, with a level of significance set at α = 0.05. RESULTS: Bond strengths, microleakage scores, microgaps, and percent marginal adaptation of Surefil One and Vertise Flow were significantly (p < 0.001) inferior to the control group. Dentin preconditioning with universal adhesives significantly increased the study parameter outcomes of Surefil One and Vertise Flow, yet they were still significantly below the performance of the control group. CONCLUSION: Conventional resin composite outperformed the SAC whether applied solely or in conjunction with their corresponding universal adhesives.

EFFICACY OF NOVEL BIOACTIVE GLASS IN THE TREATMENT OF ENAMEL WHITE SPOT LESIONS: A RANDOMIZED CONTROLLED TRIAL✰.

OBJECTIVES: to evaluate the efficacy of 2 types of bioactive glass (45S5) compared to casein-phosphopeptide stabilized-amorphous calcium phosphate (CPP-ACP) in the treatment of orthodontically-induced white spot lesions (WSLs). METHODS: Sixty post-orthodontic WSLs (ICDAS II score 2) were randomly allocated to a double blind randomized controlled trial with 3 parallel arms (n = 20). Test group I (Bio-BAG) received BiominF slurry and toothpaste, and test group II (N-BAG) received Novamin slurry and toothpaste. While the positive control group (CPP-ACP) received Recaldent paste. Products were applied daily in-office during week 1, and boosted by self-administered home application for 4 weeks (week 1-4). Standard oral hygiene care was performed by all participants twice daily during months 2-6. All patients were assessed for change in WSL dimensions using computer assisted analysis based on standardized digital intraoral photographs in addition to laser fluorescence DIAGNOdent assessment before treatment (T0) and at 1 week (T1), 1 month (T2), 3 months (T3,) and 6 months (T4) follow up periods. RESULTS: Kruskal Wallis test was used (P < .05 for all). At T4, a statistically significant (P < .001) regression of WSL was disclosed in all 3 groups compared to baseline, and a highly significant lesion size percent reduction in Bio-BAG group compared to the control group (P < .001). The mean area of the lesions decreased by 64.8%, 32.2%, and 31.6% for groups I, II and III respectively (P = .001). DIAGNOdent findings largely reflected the clinical scores (Mean scores at baseline/T4 for groups I, II, and III respectively; 16.57/3.62, 16.93/7.90, 21.95/19.27). No adverse effects were reported. CONCLUSIONS: The combined in-office and home-application of BiominF paste for 4 weeks resulted in greater esthetic improvements of post-orthodontic WSLs compared to Novamin and CPP-ACP. In addition, BiominF showed a significant reduction in fluorescence intensity which indicates potential lesion remineralization. CLINICAL RELEVANCE: Post-orthodontic WSLs can be diminished using bioactive glass remineralization therapy.

Effect of surface treatments on biaxial flexural strength, fatigue resistance, and fracture toughness of high versus low translucency zirconia.

BACKGROUND: Mechanical surface treatments can deteriorate the mechanical properties of zirconia. This study evaluated and compared the biaxial flexural strength, fracture toughness, and fatigue resistance of high translucency (HT) to low translucency (LT) zirconia after various mechanical surface treatments. METHODS: Four hundred eighty zirconia discs were prepared by milling and sintering two HT (Katana and BruxZir) and LT (Cercon and Lava) zirconia blocks at targeted dimensions of 12 mm diameter × 1.2 mm thickness. Sintered zirconia discs received one of the following surface treatments: low-pressure airborne particle abrasion (APA) using 50 µm alumina particles, grinding using 400 grit silicon carbide paper, while as-sintered specimens served as control. Internal structure and surface roughness were evaluated by scanning electron microscope (SEM) and a non-contact laser profilometer, respectively. Half of the discs were tested for initial biaxial flexural strength, while the rest was subjected to 106 cyclic fatigue loadings, followed by measuring the residual biaxial flexural strength. Fractured surfaces were examined for critical size defects (c) using SEM to calculate the fracture toughness (KIC). The effect of surface treatments, zirconia type, and cyclic fatigue on the biaxial flexural strength was statistically analyzed using three-way analysis of variance (ANOVA) and Tukey HSD post hoc tests (α = 0.05). Weibull analysis was done to evaluate the reliability of the flexural strength for different materials. RESULTS: The initial biaxial flexural strength of LT zirconia was significantly higher (p < 0.001) than that of HT zirconia in all groups. While low APA significantly increased the biaxial flexural strength of LT zirconia, no significant change was observed for HT zirconia except for Katana. Surface grinding and cyclic fatigue significantly reduced the flexural strength of all groups. High translucency zirconia reported higher fracture toughness, yet with lower Weibull moduli, compared to LT zirconia. CONCLUSION: LT zirconia has higher biaxial flexural strength, yet with lower fracture toughness and fatigue resistance, compared to HT zirconia. Low-pressure APA has significantly increased the biaxial flexural strength in all zirconia groups except BruxZir. Grinding was deteriorating to biaxial flexural strength and fracture toughness in all zirconia types. Cyclic fatigue has significantly decreased the biaxial flexural strength and reliability of HT and LT zirconia.