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Öğe Comparison of Resin Cement's Different Thicknesses and Poisson's Ratios on the Stress Distribution of Class II Amalgam Restoration Using Finite Element Analysis(Mdpi, 2023) Gonder, Hakan Yasin; Fidancioglu, Yasemin Derya; Fidan, Muhammet; Mohammadi, Reza; Karabekiroglu, SaidUsing a three-dimensional finite element analysis, this study aimed to evaluate the effect of different cements' thicknesses and Poisson's ratios on the stress distribution in enamel, dentin, restoration, and resin cement in a computer-aided design of a class II disto-occlusal cavity. Dental tomography was used to scan the maxillary first molar, creating a three-dimensional tooth model. A cavity was created with a 95 degree cavity edge angle. Resin cement with varying Poisson's ratios (V1: 0.35 and V2: 0.24) was used under the amalgam. The simulated groups' thicknesses ranged from 50 mu m to 150 mu m. A load of 600 N was applied to the chewing area. The finite element method was used to assess the stress distribution in the enamel, dentin, restorations, and resin cement. The stress in the restoration increased with the use of a 100 mu m resin cement thickness and decreased with the use of a 150 mu m resin cement thickness. For the V1 and V2 groups, the cement thickness with the maximum stress value for the enamel and dentin was 150 mu m, while the cement thickness with the lowest stress value was 50 mu m. The greatest stress values for V1 and V2 were obtained at a 150 mu m cement thickness, while the lowest stress values were observed at a 100 mu m cement thickness. Using resin cement with a low Poisson's ratio under amalgam may reduce stress on enamel and restorations.Öğe Do hemostatic agents affect shear bond strength and clinical bond failure rate of orthodontic brackets?(Taylor & Francis Ltd, 2018) Karabekiroglu, Said; Kok, HaticeTo evaluate the effects of different hemostatic agents on the shear bond strength (SBS) in vitro and clinical bond failure rate of orthodontic metal brackets in vivo. A total of 100 human premolar teeth were randomly divided into five groups: control, blood, Viscostat, hydrogen peroxide (H2O2), and epinephrine. Teeth were bonded with same light-cured adhesive and composite. After storage in distilled water for 24h, thermal cycling was used as an aging procedure on all samples. The brackets were subjected to an SBS test at a speed of 0.5mm/min until bracket debonding. SBS values and the adhesive remnant index were evaluated. Ninety-nine patients (52 female, 47 males) undergoing routine orthodontic treatment were recruited for this controlled clinical study at bonding stages. All patients with bleeding on the buccal surface of any premolar tooth or teeth at bonding were included in this study. Over 6months, the bond failure rate was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's post-hoc test (p<.05). The McNemar test was used to compare bracket-bond failure. ANOVA showed a significant difference (p<.001) between the groups. No significant differences were found between the hemostatic agent groups (p>0.05) in the in vitro part. The lowest failure rate was obtained in the control group rather than the hemostatic agent groups during clinical follow-up (p<0.05). Each of the hemostatic agents (Viscostat, H2O2, and epinephrine) can be used for bleeding management during the orthodontic bonding process. Epinephrine application showed a high bond-failure rate at clinical follow-up.Öğe The Effect of Decalcified Root Surfaces on Dentinal Bond Strength(Taylor & Francis Ltd, 2016) Ozer, Fusun; Sher, Michael; Daneshmehr, Leila; Karabekiroglu, Said; Sinmazisik, Gulden; Unlu, Nimet; Blatz, Markus B.Microtensile bond strengths of current dentin adhesives to intact and decalcified root surfaces were evaluated. Two hundred and twenty-four extracted human incisors were divided into two groups as intact (IRD) and decalcified (DRD). The roots of DRD teeth were placed in a demineralization solution to produce artificial carious-like lesions. Root surfaces were slightly ground and treated with either Scotchbond Multi-Purpose (SMP), Adper Single Bond Plus (SBP), Adper Easy Bond (AEB), Scotchbond SE (SSE), Clearfil SE Bond (CSE), Clearfil Protect Bond (CPB), Clearfil Tri-S Bond (CTS), FL-Bond II (FLB), XP Bond (XPB), iBond (IB), AdheSE Bond (ASE), Optibond Solo Plus (OSP), Prelude Dental Adhesive (PDA), and G-Bond (GB). Composite buildups were formed on the bonded surfaces. After thermocycling, hour-glass shaped specimens with an area of 1mm(2) at the bonded interface were subjected to microtensile testing. Resin-dentin interfaces were observed with SEM. Kruskal Wallis and Mann Whitney-U tests were used for statistical analysis. There was not significant difference between bond strengths to intact and decalcified dentin, with the exception of ASE and CSE, which had higher values to IRD (p < 0.05). SSE and CTS were the adhesives that showed higher bond strengths to DRD than to IRD, however the difference was not significant (p > 0.05). The self-etch adhesives performed better on both IRD and DRD surfaces than etch-and-rinse systems.Öğe Effectiveness of different preventive agents on initial occlusal and proximal caries lesions: A follow-up study(Elsevier Taiwan, 2018) Karabekiroglu, Said; Kahraman, Fatma Betul; Unlu, NimetBackground/purpose: Monitoring the effects of different caries-preventive agents on initial caries lesions in orthodontic patients is important. Therefore, the purpose of this study is to investigate the efficacy of different preventive methods in preventing occlusal and proximal incipient lesions (ILs) during fixed orthodontic treatment. Materials and methods: Forty-eight subjects at the beginning of fixed orthodontic treatment were included. All subjects were well educated and motivated to use the fluoride toothpaste (Colgate Total, 1450 ppm F) three times a day during the study period. Four different groups were created with a split-mouth design: placebo, fluoride gel, fluoride varnish, and chlorhexidine varnish. The occlusal surfaces of the second molar teeth were assessed with DIAGNOdent pen (DD) during the first 12 months (6th and 12th), and the proximal surfaces of each quadrant were monitored using bitewing radiographs until the 24th month (baseline and 24th month). Results: The mean DD values increased in each group during the first 6 months compared to the baseline, but a significant increment was only obtained in the control and fluoride gel groups (p < 0.05). Fluoride and chlorhexidine varnish had significantly more preventive effects than the control and the fluoride gel for occlusal surfaces at the 6th and 12th month and for intact proximal surfaces at the 24th month, but no significant differences were found between the two varnish groups (p > 0.05). No significant differences were found between the four methods in terms of caries progression for proximal ILs after 24 months. Conclusion: Effective toothbrushing with 1450 ppm fluoridated toothpaste and topical fluoride gel application seems to be inadequate for prevention of new proximal ILs during fixed orthodontic treatment. Fluoride and chlorhexidine varnish showed more protection in relation to occlusal surfaces. (C) 2018 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.Öğe Effectiveness of Different Preventive Programs in Cariogram Parameters of Young Adults at High Caries Risk(Hindawi Ltd, 2017) Karabekiroglu, Said; Unlu, NimetObjective. To evaluate the effectiveness of different preventive programs in young adults at high caries risk using Cariogram software. Methods. Sixty-six young adults with high caries risk were evaluated. Dental caries risk for all subjects was determined according to WHO criteria. Subjects were divided into three different preventive groups (control: OH, fluoride varnish: FV, and chlorhexidine varnish: CV). They were followed for 12 weeks (baseline: T0, 1 week: T1, 4 weeks: T2, and 12 weeks: T3). Plaque index, diet frequency, and salivary chairside tests (to record the flow rate, buffer capacity, and mutans streptococci and lactobacillus counts) were performed at each visit. Based on these data, ten caries-related variables were collected and inserted into the Cariogram software to calculate the predicted chance of avoiding caries for each subject. Results. Significant changes were obtained about the Cariogram parameters (diet, bacteria, susceptibility, circumstances, and Cariogram risk group). No significant differences were found between the three methods regarding mean Cariogram scores after 3 months (p > 0.05). Conclusions. The regular and effective short-term (three months) use of 1450 ppm fluoridated toothpaste, one visit application of fluoride, and chlorhexidine varnishes were effective for reducing caries risk in young adults, which can be clearly demonstrated using Cariogram software.Öğe Effects of different desensitizers and lasers on dentine tubules: An in-vitro analysis(Wiley, 2017) Oncu, Elif; Karabekiroglu, Said; Unlu, NimetBackgroundDentin hypersensitivity is an important clinical problem affecting a large percentage of the population, and various therapies have been suggested for its treatmentamong them desensitizing agents and lasers. The aim of this study was to evaluate the in vitro effects of different in-office desensitizing agents and different type lasers, alone or in combination, on human dentinal tubules. Materials and MethodsEighty-four dentinal specimens obtained from freshly extracted impacted third molars were included and subsequently divided into seven groups: Group 1 (Control), Group 2 (Gluma desensitizer), Group 3 (Teethmate desensitizer), Group 4 (Nd:YAG laser), Group 5 (Er:YAG laser), Group 6 (Gluma desensitizer+Er:YAG laser), and Group 7 (Teethmate desensitizer+Er:YAG laser). The dentinal specimens of all groups were evaluated using SEM. A total of 12 images per sample were taken, and the numbers of open, partially occluded, and totally visible (open+partially occluded) dentinal tubules were counted. AFM was used to further substantiate the blocking mechanism. The data were analyzed by one-way ANOVA and Dunnett-C tests. ResultsComparison of the number of occluded dentinal tubules per 100 mu m(2) revealed that the laser and laser combined-treated groups showed the most occluded dentinal tubules. Gluma desensitizer+Er:YAG laser combination demonstrated significantly more tubule occlusion than all the other groups (p<.05). ConclusionsThe results of this study show that combined treatment methods were effective in the occlusion of dentinal tubules.Öğe Occlusal Caries Detection and Diagnosis Using Visual ICDAS Criteria, Laser Fluorescence Measurements, and Near-Infrared Light Transillumination Images(Karger, 2020) Tassoker, Melek; Ozcan, Sevgi; Karabekiroglu, SaidObjective: Current diagnostic tools for non-cavitated occlusal caries are not very reliable. For this reason, newer systems need to be developed. The aim of this study was to compare the performance of visual inspection (ICDAS-II), laser fluorescence (DIAGNOdent pen), and the near-infrared transillumination technique (DIAGNOcam) in the detection of non-cavitated occlusal caries lesions under clinical and laboratory conditions in 90 third molar teeth planned for extraction. Materials and Methods:Ninety third molar teeth were firstly examined in clinical conditions, scored according to ICDAS-II criteria, and examined with DIAGNOdent pen and DIAGNOcam devices. After finishing the clinical examination, the teeth were re-evaluated shortly after the extractions with the same methods. Then, the teeth were sectioned for histological validation according to Downer's criteria. Sensitivity, specificity, accuracy, and area under the receiver operating characteristic (ROC) curves were calculated based on the histological results. Results: For the D-0-D1-4 threshold, the area under the ROC curve values ranged between 0.754 and 0.881 for all systems. Sensitivity values ranged between 80.5 and 96.1%, and specificity values ranged between 61.5 and 84.6% for the three caries detection methods. DIAGNOcam had the best correlation value (0.616) according to histological observations and demonstrated a sensitivity rate of 96.1%, a specificity rate of 61.5%, and an accuracy rate of 91.1%. Conclusions: DIAGNOcam was found to be the most effective method for the diagnosis of occlusal caries without cavitation in permanent molar teeth.Öğe Shear bond strength to enamel and failure type of different periodontal splints: an in vivo and in vitro study(Taylor & Francis Ltd, 2017) Karabekiroglu, Said; Oncu, Elif; Yildiz, Merve; Unlu, NimetThe goal of this study was to evaluate the shear bond strength (SBS) and failure mode of four different splint materials [Polyethylene FRC Ribbond Thm (RB), Polyethylene FRC Construct (Kerr), Multifilament Fishing Line (MFL), and Non Fiber Reinforced Composite (control)]. Thirty- seven subjects were randomly divided into four splint methods. After splinting procedures, the subjects were recalled 12 months later. One hundred and sixty human mandibular incisors (for extracoronal and intracoronal splinting) and 40 sheep mandibles (only extracoronal splinting) were used for the in vitro part. The specimens were subjected to SBS at their incisoproximal contact, and debonding forces were measured with a universal testing machine (1 mm/min crosshead speed). Failure sites were examined under a stereomicroscope (x40 magnification). The SBS data were assessed via analysis of variance (ANOVA) and Tukey's tests. The survival rate was significantly affected by the splint type (RB: 95.3%, Kerr: 91.6%, MFL: 93.5%, Control: 52.5%). No statistically significant differences were found between RB, Kerr, and MFL (p > 0.05) at all in vitro parts. Intracoronal splinting showed lower SBS values than extracoronal (p < 0.05). Lower SBS values were obtained in sheep teeth than human teeth (p < 0.05). Significantly different fracture patterns were noted between groups (p < 0.05). Only resin composite application seems to be inadequate for periodontal splinting. MFL splints are also economic and quite resistant, and they might be used as an alternative to fiber- reinforced composites.Öğe Teeth Restored with Bulk-Fill Composites and Conventional Resin Composites; Investigation of Stress Distribution and Fracture Lifespan on Enamel, Dentin, and Restorative Materials via Three-Dimensional Finite Element Analysis(Mdpi, 2023) Gonder, Hakan Yasin; Mohammadi, Reza; Harmankaya, Abdulkadir; Yuksel, Ibrahim Burak; Fidancioglu, Yasemin Derya; Karabekiroglu, SaidObjectives: the aim of this study was to examine the stress distribution of enamel, dentin, and restorative materials in sound first molar teeth with restored cavities with conventional resin composites and bulk-fill composites, as well as to determine their fracture lifetimes by using the three-dimensional finite element stress analysis method. Materials and Methods: an extracted sound number 26 tooth was scanned with a dental tomography device and recorded. Images were obtained as dicom files, and these files were transferred to the Mimics 12.00 program. In this program, different masks were created for each tooth tissue, and the density thresholds were adjusted manually to create a three-dimensional image of the tooth, and these were converted to a STL file. The obtained STL files were transferred to the Geomagic Design X program, and some necessary adjustments, such as smoothing, were made, and STP files were created. Cavity preparation and adhesive material layers were created by transferring STP files to the Solidworks program. Finally, a FE model was created in the ABAQUS program, and stress distributions were analyzed. Results: when the bulk-fill composite and conventional resin composite materials were used in the restoration of the cavity, the structures that were exposed to the most stress as a result of occlusal forces on the tooth were enamel, dentin, restorative material, and adhesive material. When the bulk-fill composite material was used in restoration, while the restorative material had the longest fracture life as a result of stresses, the enamel tissue had the shortest fracture life. When the conventional resin composite material was used as the restorative material, it had the longest fracture life, followed by dentin and enamel. Conclusion: when the bulk-fill composite material was used instead of the conventional resin composite material in the cavity, the stress values on enamel, dentin, and adhesive material increased as a result of occlusal forces, while the amount of stress on the restorative material decreased. In the fracture analysis, when the bulk-fill composite material was used instead of the conventional resin composite material, a decrease in the number of cycles required for the fracture of enamel, dentin, and restorative materials was observed as a result of the forces generated in the oral cavity.
