Hybrid computer-aided design and computer-aided manufacturing (CAD/CAM) materials have gained prominence in restorative dentistry due to their advantageous mechanical and esthetic properties; however, their long-term performance may be adversely affected by acidic oral environments, such as those associated with gastroesophageal reflux disease (GERD). This in vitro study aimed to investigate the effects of simulated gastric acid exposure on the surface roughness, gloss, color stability, and microhardness of two hybrid CAD/CAM materials: Vita Enamic and Cerasmart. Standardized rectangular specimens (2 mm thickness) were prepared and polished using a clinically relevant intraoral protocol. Baseline measurements were obtained for surface roughness, gloss, color change (ΔE), and Vickers microhardness. All specimens were then immersed in hydrochloric acid (pH 1.2) for 24 h to simulate prolonged gastric acid exposure, after which the same properties were re-evaluated. Post-immersion analysis revealed significant increases in surface roughness and reductions in gloss and microhardness for both materials (p < 0.05), with Vita Enamic demonstrating greater susceptibility to degradation. Color changes remained below the clinically perceptible threshold, with no significant differences between materials. These findings highlight the potential vulnerability of hybrid CAD/CAM materials to acidic environments and underscore the importance of careful material selection in patients predisposed to acid-related challenges.

The surface roughness of different glass–ionomer-based materials and their shear bond strength with a resin composite with and without thermal cycling were evaluated. Ketac Molar (KM, 3M ESPE, St. Paul, MN, USA), Glass Carbomer (GC, GCP Dental, Leiden, The Netherlands), Bioactive (BA, PULPDENT, Corporation, Watertown, MA, USA) and Fuji II LC (FJ, GC, Tokyo, Japan) were used to prepare the specimens and they were kept in distilled water at 37 °C for 24 h. The surface roughness of the specimens was measured with a profilometer (n = 6). A universal adhesive resin was applied on glass–ionomer materials and cylindrical universal composites were applied and polymerized, respectively (n = 16). The specimens were divided into two subgroups. The first subgroup was subjected to thermal cycling. Shear bond strength was investigated for both subgroups (n = 8). Stereomicroscopy and SEM examinations were performed. The roughest surface was obtained in the GC group (p < 0.05). The shear bond strength of the specimens without thermal cycling was higher than that of those with thermal cycling (p < 0.05). The lowest shear bond was measured in the GC group (p < 0.05). Although FJ, KM and BA have been observed to be suitable materials for clinical use, BA, in particular, is evidenced to become the best option among the materials we tested. GC cement’s long-term performance needs to be improved.

The repair of defective composite restorations, particularly bulk-fill composites, offers a conservative alternative to complete replacement. However, establishing durable adhesion between aged and fresh composites remains a clinical challenge due to the altered surface properties of aged materials. This in vitro study investigated the effects of different surface treatment protocols (no treatment, diamond bur roughening, and air abrasion) and adhesive systems (G-Premio Bond, Clearfil SE Bond, and Adper Single Bond 2) on the shear bond strength (µSBS), tensile bond strength (µTBS), and microleakage of repaired bulk-fill composites. Results demonstrated that both surface treatment and adhesive type significantly affected bond strength (p < 0.05). Mechanical surface treatments, particularly diamond bur roughening and air abrasion, enhanced µSBS and µTBS compared to untreated controls. The highest µSBS and µTBS values were observed with diamond bur treatment combined with Adper Single Bond 2, reaching mean values of 25.8 ± 2.1 MPa and 28.3 ± 1.8 MPa, respectively. Air abrasion with Clearfil SE Bond also significantly increased bond strengths (µSBS: 22.1 ± 2.0 MPa; µTBS: 23.5 ± 1.7 MPa) relative to no treatment (p < 0.05). Micro-computed tomography analysis revealed that Clearfil SE Bond following diamond bur roughening resulted in the lowest microleakage scores, with a mean leakage volume of 0.12 ± 0.04 µm. These findings underscore the importance of mechanical surface conditioning and appropriate adhesive selection to enhance both bond strength and sealing efficacy in composite repair procedures.

Objective: The aim of this study is to investigate the depth of cure (DOC) of the bulk fill composite samples prepared in different thicknesses with two different modes of light curing device with Vickers hardness tester.Methods: Five different bulk-fill composite materials were used in the present study. 20 sample of 2 mm and 20 sample of 4 mm thick samples were prepared, 10 samples from each group were polymerized for 20 seconds with the standard mode (Mode 1) of the light curing device and 10 samples polymerized with soft-start mode (Mode 2) for 25 seconds (n=10). Hardness measurements were made from the upper and lower surfaces of each sample and the hardness ratio was calculated. The statistical analysis was performed using three-way analysis of variance (ANOVA) and Tukey multiple comparisons (p = 0.05).Results: The hardness ratios of all composites were determined to be over 80%, which is clinically acceptable. There was a statistically significant difference between the DOC levels according to the composites (p <0.05). There was a statistically significant difference according to the thickness (p 0.05).Conclusions: The surface hardness ratios of all groups were determined to be over 80%, which is clinically acceptable. The polymerization with soft start technique may not different from the standard-mode for polymerization depth.

Objective: Aim of this study is to examine the effects of chewing gums with different contents on the salivary flow rate, pH and ion exchange in healthy subjects. Material and Method: Twenty healthy individuals with DMFT scores of ≤ 4, who did not use any medication or diagnosed with any systemic disease that could change flow and characteristics of saliva were selected as study sample. The unstimulated saliva of all individuals on day one was collected in sterile test tubes. After 24 hours, saliva stimulated by chewing paraffin was collected from each individual as a control group. Then, five different chewing gums were used for 6 minutes for seven days at 24-hour intervals (Vivident Xylit, Oneo White, Trident Recaldent, Fluogum, CB12 Boost). Saliva samples were collected at 0-1, 1-3 and 3-6 minute intervals in graduated sterile test tubes. The pH of saliva collected at the end of each test period was measured with litmus paper to minimize any time-dependent pH changes. Flow rate was calculated in ml/min. Ion exchanges were evaluated according to the spectrophotometric method. Statistical analysis was performed using IBM SPSS Statistics, Version 23.0 statistical program. Statistically significance level was set as p<0.05. Results: Calcium concentration of the collected saliva was found to be higher in the gum group containing tricalcium phosphate than in the other groups. Calcium carbonate containing gum group showed increased salivary flow rate and lower pH when compared to other groups. Conclusion: Chewing gum containing calcium carbonate and tricalcium phosphate may have beneficial effects on the structure of saliva and beneficial effects in terms of oral and dental health. Keywords: Calcium concentration, Chewing gum, Ion Exchange, pH, Salivary flow rate

Amaç: Diş hekimliğinde estetik problemlerin büyük bir kısmını ön bölgede görülen renk, şekil, yapı ve konum bozuklukları oluşturmaktadır. Özellikle diastemalar, hastaların ortak estetik şikayetlerinden biridir. Yaygın görülebilen bu tür estetik problemleri ortadan kaldırmak amacıyla uygulanan ve ortodontik, protetik, restoratif işlemleri içeren farklı tedavi prosedürleri mevcuttur. Direkt kompozit restorasyonlar, estetik olmayan dişler arası boşlukların kapatılması için konservatif, pratik ve düşük maliyetli bir tedavi seçeneğidir.Bu olgu sunumunda dişlerindeki diastema ve polidiastemaya bağlı estetik şikayetle kliniğimize başvuran hastalara, direkt kompozit rezin ile uygulanan restoratif tedavi işlemlerinin anlatılması amaçlandı. Bulgular: Restorasyonların tamamlanmasının ardından, hastaların 3-6 ve 12 aylık periyodik takip randevuları gerçekleştirildi. Takipler sonucunda yapılan restorasyonların estetik başarısının klinik olarak kabul edilebilir ölçüde olduğu görüldü.Sonuçlar: Direkt kompozit rezin restorasyonların diastema kapatma için uygun maliyetli, kolay uygulanabilir ve klinik olarak başarılı olduğu söylenebilir.Anahtar Kelimeler: dental restorasyon, diastema, estetik, kompozit rezin