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    Effect of Disposable Sheaths on the Vickers Microhardness of Resin Composites
    (Marmara Univ, Inst Health Sciences, 2021) Atay, Meltem Tekbas; Dindar, Mediha Buyukgoze; Ozveren, Neslihan
    Objective: The aim of this study was to evaluate the effect of disposable sheaths on microhardness of resin composites. Methods: A total of 40 resin composite specimens were fabricated with disc-shaped perspex molds (5x2 mm). Specimens were divided into 4 groups: Irradiated by 1-Elipar LCU (EL), 2-Elipar LCU with sheath (ELS), 3-Valo LCU (VL), 4-Valo LCU with sheath (VLS), (n=10). The specimens were subjected to surface microhardness (SMH) test (Tronic, Digital Microhardness Tester DHV-1000) on the top and bottom surfaces under 200 g load applied for 10 s with a Vickers indenter. The specimens were stored in the distilled water at 37 degrees C for 24 hours and the same measurements were repeated. One-way ANOVA test, Tukey and Tamhane post-hoc tests were used for intergroup comparisons. Also paired sample t-test was used for comparisons of the different time results. Results: According to the 1st-hour data from the top and bottom SMH measurements, EL and VL groups have significantly higher microhardness values than VLS and ELS groups (p<0.05). There was a dependent change in the top surface measurements with the time (p=0.000), but also interaction with the LCU (p=0.000). All groups showed significant microhardness decrease from 1st to 24th-hour for both top and bottom values (p<0.05) except for top SMH of VLS group (p=0.151). Conclusion: Disposable sheaths decreased the light output of the LCU's and caused reduction in the SMH. Although they are effective in preventing cross-infection, they significantly reduced the polymerization efficiency, thereby mechanical properties of resin composites.
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    The effect of toothbrush abrasion on wear and surface roughness of direct and indirect composite laminate veneer restorations
    (Iop Publishing Ltd, 2020) Dindar, Mediha Buyukgoze; Atay, Meltem Tekbas
    Direct and indirect composite laminate veneers have been frequently used, however the wear of composite restorative materials is still a major problem. Objective: This study aimed to investigate the surface roughness and wear of composite laminate veneers made by two different methods after toothbrushing simulation. Material and Methods: Ninety-six upper incisors and canines were divided into two groups: 1-Componeer prefabricated composite veneer (CPV), 2- Uveneer direct composite veneer (UDV). At the UDV group, restorations were made by using Uveneer template system with the same nanofilled composite material (Synergy D6, Coltene, Altstatten, Switzerland) of the prefabricated Componeers'. The initial surface roughness was measured with a profilometer, then the weight was measured. Before the simulation, samples were screened with a 3D extra-oral scanner. Toothbrush simulation was performed at 10,000 rotational strokes with 2.5 N. The measurements were repeated after toothbrushing simulation. Data were analyzed using variance analyses and t-tests (p < 0.05). Results: Before and after polishing, a significant difference was found between two groups' surface roughness in both lateral incisors (p = 0.000, p = 0.000) and canines (p = 0.048, p = 0.001), respectively. After toothbrushing simulation, significant increases were observed in central and lateral incisors' surface roughness with two methods. There was no significant difference between weight loss (p > 0.05). In 3D scans, wear rate was quite similar except UDV group central incisors. Conclusions: Surface roughness of the CPV restorations were less affected after toothbrushing simulation. However, the Uveneer template system, a facilitated treatment procedure compared to the manual buildup of direct restoration, has shown comparable results with CPV's.
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    Evaluation of third molar agenesis associated with hypodontia and oligodontia in turkish pediatric patients
    (Istanbul Univ Press, Istanbul Univ Rectorate, 2020) Atay, Meltem Tekbas; Ozveren, Neslihan; Serindere, Gozde
    Purpose To evaluate the association between third molar (M3) agenesis and hypodontia and oligodontia in pediatric patients by using panoramic radiography. Materials and Methods Panoramic radiographs of 1,471 patients (899 females; 572 males) and 5,884 teeth were retrospectively evaluated. The age and gender of the patients were recorded. Patients ages 9-15 years old were included in the study. The mean age was 12.76. The agenesis of M3 teeth and the relationship between M3 agenesis and hypodontia and oligodontia were recorded according to findings from the upper and lower jaw, in both the right and left locations, along with the number of M3 with agenesis. Data were analyzed using chi-square and McNemar tests (p<0.05). Results A total of 1,319 (89.7%) patients had all M3 teeth present in the mouth, while the other 152 (10.3%) had congenital agenesis in one or more teeth. The number of teeth in which M3 agenesis was seen, in order of the number of missing M3 teeth, the percentages were 2.6% for one, 2.4% for two, 1.0% for three and 4.3% for four missing teeth.Hypodontia was detected in 37 patients and oligodontia was detected in 3 patients. Conclusion The prevalence of M3 agenesis varies from one population to another. Two of the dental anomalies associated with M3 agenesis are hypodontia and oligodontia. In this study, M3 agenesis varied in terms of region and gender; hypodontia was also significantly higher in patients with missing mandibular M3.
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    Long-term effect of curcuminoid treatment on resin-to-dentin bond strength
    (Wiley, 2022) Atay, Meltem Tekbas; Seseogullari-Dirihan, Roda; Mutluay, Mustafa Murat; Tezvergil-Mutluay, Arzu
    Endogenous dentin proteases contribute to the degradation of collagen fibrils in the hybrid layer. Recently, inhibition of host-derived proteases by curcuminoids has shown promising results. The aim of this study was to evaluate the effect of curcuminoid treatment on the microtensile bond strength (mu TBS) after 24 h or 12 months of storage. Fifty-four extracted sound human molars were flattened to mid-coronal dentin and divided into nine groups. After phosphoric acid-etching for 15 s, the dentin was experimentally treated for 60 s using 100 mu M or 200 mu M of curcumin, diflourobenzocurcumin, or demethoxycurcumin dissolved in 1% and 2% dimethyl sulfoxide (DMSO)/water solutions. Untreated and DMSO-treated groups served as controls. After bonding agent application, each tooth was restored with dental composite. The molars were sectioned into 0.9 x 0.9 x 6 mm beams. The mu TBS testing was performed after 24 h and 12 months of storage in artificial saliva. Data were analyzed using regression analyses. Failure patterns were evaluated using scanning electron microscopy. Dentin treatment with curcuminoids did not adversely affect 24-h mu TBS compared to controls. After 12 months, the mu TBS of curcuminoid groups was statistically significantly higher than the controls. This study indicates the feasibility of using curcuminoids as protease inhibitors.
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    Microbiological and SEM assessment of atraumatic restorative treatment in adult dentition
    (Springer Heidelberg, 2021) Atay, Meltem Tekbas; Koray, Fatma
    Objectives To investigate the practicability of atraumatic restorative treatment (ART) in adults in terms of marginal adaptation of restorations and microbiological changes in residual carious dentin. Materials and methods The occlusal dentin caries of 25 permanent molar teeth were removed with hand instruments. The total counts of bacteria (TCB) and the facultative anaerobic bacteria (FAB), mutans streptococci (MS), and Lactobacillus spp. (LB) counts in the affected dentin were evaluated quantitatively. The weights of the samples were measured with an electronic balance (Shimadzu, Type AX200, Japan). The cavities were restored with glass ionomer cement (Ketac(TM) Molar Easymix, ESPE Dental AG, Seefeld, Germany). Twenty replicas of randomly selected ART restorations were prepared and marginal adaptation was evaluated by scanning electron microscopy (SEM). After 6 months, the same protocols were repeated. Data were analyzed with paired sample t-tests, Wilcoxon t-tests, Pearson and Spearman correlations, and chi-square tests (p<0.05). Results In the sixth month, restoration loss and pulpitis were not observed. The mean weight of samples removed from the cavity floor was less than the baseline (0.014 +/- 0.009 and 0.023 +/- 0.013 g, respectively) (p<0.01), and the counts of total bacteria, FAB, MS, and LB significantly decreased compared to baseline (p<0.01). The frequency of marginal gaps was increased (p< 0.01). Conclusions ART showed that the counts of microorganisms decreased after 6 months although the marginal gap rates of restorations increased.