Background: This study aimed to evaluate the fracture resistance of immediate and delayed restorations after root canal treatment (RCT). Methods: Sixty human intact premolar teeth were used. Teeth were prepared disto-occlusally. After RCT, teeth were randomly divided into two groups according to restoration times (immediate or 3 months delayed). The three month delay was imitated by thermomechanical aging. Then, samples were divided into six subgroups (n = 10). While I (Composite resin), II (Flowable bulk-fill) and III (Ribbond+Flowable bulk-fill) were restored immediately, Groups IV, V and VI were restored with temporary filling material and stored in distilled. After subjected to thermo-cycling (2,500 cycles, 5–55 °C) and exposed to 60,000 cycles in a chewing simulator, Group IV (Composite resin), V (Flowable bulk-fill) and VI (Ribbond+Flowable bulk-fill) were restored. All of the teeth were fractured on the universal testing machine. Failure modes were analyzed using scanning electron microscope. Data were analyzed using the Shapiro-Wilk and two-way ANOVA tests (p < 0.05). Results: The highest fracture resistance was recorded in Group III while the lowest in Group VI. No statistically significant difference was observed among groups (p > 0.05). Most of the repairable fractures were seen in Groups I and II. Conclusion: Delaying the permanent restorations of teeth for 3 months did not affect fracture resistance. However, it was suggested to avoid delaying restorations for obtaining repairable surfaces.

The aim of this study is to evaluate the effect of different surface treatments and adhesives on shear bond strength (SBS) in the repair of composite resin restorations. In this study, 60 discs (2 mm x 10 mm) were prepared using a universal nanohybrid composite resin (GrandioSo, Voco, Germany). The discs were aged by exposure to 5000 thermal cycles between 5 and 55 °C for 30 s with an immersion procedure. Then samples were divided into 3 groups (n:20) according to the surface treatments (Group 1: no surface treatment, Group 2: roughening by bur, Group 3: roughening by Er, Cr: YSGG laser). Subsequently, the specimens were classified into two groups (n:10) according to the adhesive systems; a two-step self-etch adhesive (Clearfil SE bond (SE)), or a universal adhesive (Scotchbond Universal Plus (SB)). After surface treatments and adhesive applications, the same universal nanohybrid composite resin with a height of 2 mm and a diameter of 3 mm was placed in the center of the samples. The samples were then submitted to the SBS test using universal testing equipment (Autograph AGS-X; Shimadzu, Kyoto, Japan) with a crosshead speed of 1 mm/min. The failure modes were examined using a stereomicroscope. The surface topography of the roughened and fractured surfaces resin composite (n = 1) was assessed using scanning electron microscopy (SEM). Analyses were performed using IBM SPSS 25 programme (p < 0.05). The highest bond strength was observed in the laser + SE group (22.69 ± 4.49), while the lowest was recorded in the control + SE group (14.12 ± 3.00). In the SE adhesive group, no significant difference was found between the laser + SE and bur + SE groups (p > 0.05). Similarly, in the SB adhesive group, there were no significant differences among the surface roughening procedures (p = 0.078). Additionally, no significant differences were observed between the adhesives according to various surface roughening procedures. The failure mode was predominantly cohesive in old composites. The bond strength can be improved by surface treatments such as diamond burs, Er, Cr: YSGG laser application for better bonding strategies in the repair of nanohybrid resin composite restorations. There was no statistically significant difference in bond strength between the adhesives tested in this study.

The aim of this study was to evaluate the effect of chlorhexidine and/or ethanol application on the bond strength of two universal adhesive systems. 36 extracted human teeth were used in this study. Standard Class I cavities (4 x 3 x 3mm) were prepared and divided into two groups according to the adhesive systems used. Each group was subdivided into three subgroups to be treated with chlorhexidine, ethanol, or unexposed to any solution. Group I; Universal bond I was applied without any treatment. Group II; 2% chlorhexidine was applied, before the application of universal bond I. Group III; 100% ethanol was applied, before the application of universal bond I. Group IV; Universal bond II was applied without any treatment. Group V; 2% chlorhexidine was applied, before the application of universal bond II. Group VI; 100% ethanol was applied, before the application of universal bond II. Then, teeth were restored with a nano-hybrid resin composite then subjected to thermo-cycling (10,000 cycles, 5-55 degrees C). All teeth were exposed to 50,000 cycles of loading in a chewing simulator. Twelve sticks from each group were obtained using a cutting machine. Sticks were subjected to a microtensile bond strength. After procedures, fractured surfaces were observed under a stereomicroscope to determine the mode of failure. Hybrid layer of each group was evaluated under a scanning electron microscope (SEM). Data were submitted to the Kruskal Wallis test. Significance level was set at 5%.No statistically significant differences were shown in all groups (p > 0.05). The lowest bond strength value was obtained in group II (9.76), the highest bond strength value was determined in group IV (20.57). The study concluded that additional chlorhexidine or ethanol treatment may not influence directly the bond strength of universal adhesives when using a single-step self etch mode of universal adhesives.

This study aimed to evaluate the surface roughness and Streptococcus mutans adhesion on two different composite resin materials following the application of various polishing systems. Eighty disk-shaped specimens (8 mm diameter, 2 mm thickness) were fabricated using nanohybrid (Charisma Topaz) and nanofilled (Tokuyama Estelite Asteria) composite resins (n = 40 each). Each material group was further divided into four groups (n = 10) according to the polishing system used: Mylar strip (control), Sof-Lex™, Clearfil™ Twist Dia, and Opti1Step™. After measuring the surface roughness, the sterilized samples were divided into two subgroups as, “artificial saliva-treated samples” and “non-treated samples.” For each subgroup, solutions containing S. mutans were added, and the samples were incubated at 35–37 °C for 24 h. Determination of adhered bacteria on surfaces depended upon colony counts obtained after incubation, which was presented as CFU/mL. Statistical analyses included two-way ANOVA for surface roughness and three-way ANOVA with Tukey post hoc test for bacterial adhesion. SR values ranged from 0.07 ± 0.01 μm to 0.09 ± 0.03 μm across all groups, remaining well below the clinical threshold of 0.2 μm, highlighting that the minor surface variations observed are unlikely to have clinical significance regarding plaque retention. (p > 0.05). S. mutans adhesion values ranged between 2.83 ± 0.25 log CFU/mL and 3.57 ± 0.32 log CFU/mL. No statistically significant differences were found between polishing methods or saliva conditions (p > 0.05). The three-way ANOVA revealed a statistically significant main effect of composite resin material on S. mutans adhesion (F = 29.895, p < 0.001, partial η² = 0.322), indicating that bacterial colonization varied according to the resin material used. While different polishing systems did not significantly affect surface roughness or bacterial adhesion, the composite resin type appears to play a crucial role in S. mutans colonization.

The aim of this study was to evaluate dental treatment procedures performed under general anesthesia in adult patient. The clinical records of 94 patients between the ages of 16 and 79, whose dental treatments were completed under general anesthesia between January 2021 and 2023, were evaluated retrospectively. Fisher's Exact Test and Pearson Chi-Square Test were used to compare the obtained data according to groups. The significance level was taken as p<0.050. A statistically significant difference was found in the restorative and periodontal treatments performed under general anesthesia between systemic diseases/disabled and healthy groups (p=0.002). A statistically significant difference was found between the duration of general anesthesia of systemic diseases/disabled and healthy groups (p= 0.013). In ASA I and ASA II scoring, a statistically significant difference was found (p=0.001). The fact that restorative and periodontal treatments are needed more in unhealthy/disabled individuals has shown that oral hygiene is inadequate in unhealthy/disabled individuals. Systemically healthy patients had more dental treatments under general anesthesia in our hospital than unhealthy patients due to anxiety. Performing dental procedures under general anesthesia in appropriate indications for adult patients is a preferable method today, as dental treatments are completed in a single visit and the possibility of the patient's lack of cooperation in the chair is eliminated.