Objective: To evaluate the effect of COVID-19 preventive mouthwashes on the surface hardness, surface roughness (Ra), and color change (ΔE) of three different polymer-based composite CAD/CAM materials (Vita Enamic (ENA), Grandio Block (GB), Lava Ultimate (LU)). Methods: A total of 100 rectangular-shaped specimens with dimensions of 2 mm × 7 mm × 12 mm were obtained by sectioning three different CAD/CAM blocks and randomly divided into five subgroups according to the 30 days of mouthwash immersion protocol as follows: Control: artificial saliva, PVP-I: 1% povidone-iodine, HP: 1.5% hydrogen peroxide, CPC: mouthwash containing 0.075% cetylpyridinium chloride, EO: mouthwash containing essential oils. Microhardness, Ra, and ΔE values were measured at baseline and after 30 days of immersion protocols. Data were analyzed using the Wald Chi-square, two-way ANOVA, and post hoc Tukey tests. Results: The independent factors (materials and solutions) significantly influenced the microhardness and color ( p < 0.001). Ra of the materials was not affected by any of the mouthwashes ( p > 0.05). The microhardness and color of each material varied significantly after immersion in PvP-I and HP ( p < 0.05). The highest percentage change in microhardness, Ra, and ΔE was found in LU immersed in PvP-I and HP mouthwashes, while the lowest change was found in ENA groups ( p < 0.05). Conclusion: Within the limitations of this study, it was found that the surface hardness and color of tested polymer-based composite CAD/CAM materials are susceptible to degradation and change after 30 days of immersion in 1% PvP-I and 1.5% HP mouthwashes.

This study aimed to evaluate the effect of direct restorations using unidirectional glass fiber orientations and a short-fiber-reinforced composite (SFRC) on the fracture resistance of endodontically treated premolars with mesio-occluso-distal cavities. Ninety double-rooted premolars were selected. Fifteen teeth were left intact/as a control group. The endodontic treatment and cavity preparations of seventy-five teeth were performed and divided into five experimental groups: Resin composite (RC), modified transfixed technique + RC, circumferential technique + RC, cavity floor technique + RC, and SFRC + RC. All teeth were fractured under oblique static loading at a 30° angle using a universal testing machine. The fracture patterns were observed and classified. Data were analyzed with one-way analysis of variance, Pearson chi-square, and Tukey HSD post hoc tests (p = 0.05). The highest fracture strength values were obtained in intact teeth (599.336 N), followed by modified transfixed + RC treated teeth (496.58 N), SFRC + RC treated teeth (469.62 N), RC (443.51 N), circumferential + RC treated teeth (442.835 N), and cavity floor + RC treated teeth (404.623 N) (p < 0.05). There was no significant difference between the RC and the circumferential technique + RC (p > 0.05). Unrepairable fractures were observed at low rates (20%) in the modified transfixed + RC and SFRC + RC teeth, and at higher rates in RC (73.3%), cavity floor + RC (60%), and circumferential + RC (80%) teeth. The application of an SFRC or the modified transfixed technique yielded an improved fracture strength and the fracture pattern of ETPs being restored with a universal injectable composite.

Objective: Non-carious cervical lesions (NCCLs) are commonly observed in clinical dentistry, leading to tooth fractures, sensitivity, and compromised pulp vitality. Therefore, their restoration is essential for both the aesthetic and structural integrity of teeth. This study aimed to compare the fracture resistance of NCCLs restored using different materials: an injectable universal composite, flowable bulk-fill composites with or without fiber-reinforcement. Methods: Seventy-five double-rooted maxillary premolars were selected for the study. Fifteen teeth were left intact as a control. A wedge-shaped cavity was prepared in the cervical region of the remaining sixty teeth, which were then divided into four groups ( n = 15): unrestored, restored with an injectable composite, restored with a flowable bulk-fill composite (SDR^® flow+), and restored with a flowable short-fiber-reinforced composite (everX Flow™). All teeth underwent fracture testing under oblique static loading at a 30° angle using a universal testing machine. Fracture patterns were classified as repairable, possibly repairable, or unrepairable. Data were analyzed using one-way analysis of variance, Pearson chi-square, and Tukey HSD post hoc tests ( p = 0.05). Results: Intact teeth exhibited the highest fracture resistance (743.481 N), while unrestored teeth showed the lowest (371.49 N) ( p < 0.001). There was no significant difference in fracture resistance between the injectable composite (553.289 N) and SDR^® flow+ (497.368 N) ( p = 0.055). The everX Flow™ group displayed significantly higher fracture resistance (673.787 N) ( p < 0.001) and a repairability rate of 60% within the restored groups. Unrestored (60%), injectable composite (53.3%), and SDR^® flow+ (53.3%) groups were mostly unrepairable. Conclusion: The everX Flow™ demonstrated improved fracture resistance and favorable fracture pattern for maxillary premolars with wedge-shaped NCCLs.

The aim of this study was to evaluate the whitening and abrasion effects of dentifrices containing different whitening agents on artificially stained and unstained enamel. 160 human dental enamel discs were distributed into four groups according to the type of dentifrices applied on them (n=40): Group I, non-whitening dentifrice (control group); Group II, dentifrice containing charcoal; Group III, dentifrice containing blue covarine; Group IV, dentifrice containing hydrogen peroxide. Half of the specimens in each group were immersed in coffee solution. Color measurements were evaluated from stained and unstained specimens before and after brushing by a spectrophotometer. The surface roughness of each unstained specimen was analyzed using a profilometer after the brushing and bleaching. The surface of one randomly selected specimen from each group was observed using a scanning electron microscope (SEM). Statistical analysis of the color change was performed using the Kruskal-Wallis test. The one-way ANOVA was used to evaluate surface roughness. Group III provided significantly higher recovery on ∆E00 values than other groups on the unstained enamel (p<0.05). Group IV showed significantly the highest ∆E00 values on stained enamel (p<0.05) and also Group IV showed the highest surface roughness values (p<0.05), SEM revealed a more irregular surface in groups III and IV. It can be stated that dentifrice containing blue covarine is both an effective and a safe way to provide whiter teeth with routine home tooth brushing.

This in vitro study evaluated short-fiber-reinforced composite materials and fiber-reinforced restorations of endodontically treated molars with furcal perforation. The endodontic treatment and mesio-occlusal–distal cavity preparation of 126 two-rooted mandibular third molars were performed. Eighteen non-perforated teeth were restored with resin composite as the control group. Furcal perforations and repair were performed on 108 teeth that were divided into six experimental groups: resin composite (RC), everX Flow (EXF), everX Posterior (EXP), Bioblock (BB), modified transfixed (MT), and horizontal glass-fiber (HGF) groups (n = 18). Fracture resistance tests were performed at an angle of 30◦ using a universal testing machine under static loading, and fracture patterns were classified. Welch’s analysis of variance, Pearson chi-square, and Tamhane post hoc tests (p = 0.05) were used to analyze the data (p = 0.05). The highest fracture resistance values were seen with the HGF (596.305 N), followed by MT (540.365 N), BB (477.906 N), EXP (476.647 N), EXF (414.462 N), control (413.811 N), and RC (335.325 N) groups (p < 0.001). There was no significant difference between the BB and EXP groups or between the EXF and control groups (p > 0.05). In terms of the dominant fracture pattern, the HGF and MT groups were repairable and possibly repairable, whereas the control, RC, and EXP groups were unrepairable. The EXF and BB groups were almost equally divided between possibly repairable and unrepairable. Restorations using horizontal fiber techniques and short-fiber-reinforced materials increased the fracture resistance of endodontically treated teeth with furcal perforation.

Amaç: İki cam iyonomer restoratif sistem (EQUIA Fil, Ionostar Molar) ve bir kompozit rezinin (Charisma Classic ) mekanik ve yüzey özelliklerinin kıyaslanması Gereç ve Yöntemler: Her materyalden 20 adet disk şeklinde örnek teflon kalıpta, üretici talimatları doğrultusunda hazırlandı. Örnekler distile suda 37 ⁰C de 24 saat bekletildikten sonra 10 örnekte mikrosertlik, 10 örnekte yüzey pürüzlülük ölçümleri yapıldı ve ölçümler 5000 ve 10000 ısısal döngü sonrası tekrar edildi. Tarama elektron mikroskopisi değerlendirmesi için her materyalden üçer örnek daha hazırlandı. Veriler Wİlcoxon işaretli sıralar ve Bonferroni düzeltmeli çoklu karşılaştırma testi kullanılarak değerlendirildi. Bulgular: Equia ısısal döngü sonrası mikrosertliğinde anlamlı bir değişim göstermemiştir ( p > 0.0056) . Ionostar Molar ve Charisma Classic ise 5000 ve 10000 ısısal döngü sonrası başlangıç mikrosertliğine göre anlamlı azalma gözlenmiştir (ikisi de; p < 0.0056). Ancak, Charisma Classic materyalinin 5000 ve 10000 ısısal döngü sonrası mikrosertlik değerleri arasında fark gözlenmemiştir (p = 0.007). Yüzey pürüzlülüğü değerlendirildiğinde, Ionostar Molar başlangıç ve ısısal döngü sonrası grupları arasında anlamlı fark tespit edilmemiştir ( p > 0.0017 ). Benzer şekilde, Equia ve Charisma Classic gruplarında başlangıç ve 5000 ısısal döngü sonrası grupları arasında istatistiksel anlamlı fark gözlenmemiştir ( p > 0.0017 ). Ancak 10000 ısısal döngü sonrası Equia ve Ionostar Molar gruplarında yüzey pürüzlülük değerleri başlangıç değerlerine gore anlamlı derecede artmıştır (sırasıyla; p < 0.001 ve p = 0.002). Sonuç: Equia ve Ionostar Molar, rezin kompozite benzer mekanik özellikler göstermiştir ve bu sebeple kalıcı restorasyonlarda kullanım için ümit vaat etmektedir. Anahtar kelimeler: Cam iyonomer, tarayıcı elektron mikroskobisi, yüzey özellikleri Background: To evaluate the mechanical and surface properties of two glass ionomer restorative systems (EQUIA Fil, Ionostar Molar) and a resin composite (Charisma Classic ) after thermocycling. Methods: Twenty disk-shaped samples were prepared from each material in teflon molds according to manufacturer’s instructions. After the samples were stored in distilled water at 37 ⁰C for 24 h, microhardness and surface roughness measurements were performed from each group and repeated after 5000 and 10000 thermocycling. Scanning electron microscopy examinations were also performed. The data were analyzed by using Wilcoxon signed rank and Bonferroni corrected multiple comparison tests. Results: EQUIA did not exhibit significant differences in its micohardness values after thermocycling ( p > 0.0056). In contrast, Ionostar Molar and Charisma Classic exhibited statistically significant decreases in baseline microhardness after 5000 and 10000 thermocycling processes (each p < 0.0056). However, there were no significant differences between 5000 and 10000 thermocycling groups for Charisma Classic (p = 0.007). Ionostar Molar exhibited no statistically significant differences between its surface roughness values before and after thermocycling groups ( p > 0.0017 ). Similarly, there were no significant differences between baseline and 5000 thermocycling groups for EQUIA and Charisma Classic ( p > 0.0017). However, a statistically significant increase was observed after 10000 thermocycles for both of these two materials ( p < 0.001 and p = 0.002, respectively). Conclusion: The EQUIA and Ionostar Molar exhibited mechanical features similar to those of a resin composite, and thus, represent promising materials for permanent restorations. Keywords: Glass ionomer, scanning electron microscopy, surface properties