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Öğe Activation properties of trigeminal motoneurons in participants with and without bruxism(Amer Physiological Soc, 2013) D'Amico, Jessica M.; Yavuz, S. Utku; Saracoglu, Ahmet; Atis, Elif Sibel; Gorassini, Monica A.; Turker, Kemal S.In animals, sodium-and calcium-mediated persistent inward currents (PICs), which produce long-lasting periods of depolarization under conditions of low synaptic drive, can be activated in trigeminal motoneurons following the application of the monoamine serotonin. Here we examined if PICs are activated in human trigeminal motoneurons during voluntary contractions and under physiological levels of monoaminergic drive (e. g., serotonin and norepinephrine) using a paired motor unit analysis technique. We also examined if PICs activated during voluntary contractions are larger in participants who demonstrate involuntary chewing during sleep (bruxism), which is accompanied by periods of high monoaminergic drive. In control participants, during a slowly increasing and then decreasing isometric contraction, the firing rate of an earlier-recruited masseter motor unit, which served as a measure of synaptic input to a later-recruited test unit, was consistently lower during derecruitment of the test unit compared with at recruitment (Delta F = 4.6 +/- 1.5 imp/s). The Delta F, therefore, is a measure of the reduction in synaptic input needed to counteract the depolarization from the PIC to provide an indirect estimate of PIC amplitude. The range of Delta F values measured in the bruxer participants during similar voluntary contractions was the same as in controls, suggesting that abnormally high levels of monoaminergic drive are not continually present in the absence of involuntary motor activity. We also observed a consistent "onion skin effect" during the moderately sized contractions (<20% of maximal), whereby the firing rate of higher threshold motor units discharged at slower rates (by 4-7 imp/s) compared with motor units with relatively lower thresholds. The presence of lower firing rates in the more fatigue-prone, higher threshold trigeminal motoneurons, in addition to the activation of PICs, likely facilitates the activation of the masseter muscle during motor activities such as eating, nonnutritive chewing, clenching, and yawning.Öğe Clinical Study on the Comparison of Masticatory Efficiency and Jaw Movement Before and After Temporomandibular Disorder Treatment(Chroma Inc, 2013) Kuembueloglu, Oevuel; Saracoglu, Ahmet; Bingoel, Pinar; Hatipoglu, Anil; Oezcan, MutluIn this clinical study, pre- and post-rehabilitation changes in intraborder mandible movements, chewing cycles, masticatory efficiencies, and borders of the chewing area of patients with unilateral muscular disorders (MD) (n=20) or unilateral disc derangement disorders (DDD) (n=20) of temporomandibular disorder (TMD) were observed and compared with healthy individuals with full dentition (n=20) (48 female, 12 male; mean age: 28). The MD patients received stabilization splints and the DDD patients, anterior positioning splints for six weeks. Symptoms, such as muscle pain, TMJ pain, headache, chewing difficulty, and maximum mouth opening, showed significant improvements after splint therapy for both MD (p=0.000) and DDD (p=0.000) patients, but lateral excursion and protrusion were not significantly changed (p>0.05). Chewing efficacy and chewing cycles improved significantly (p<0.05) in both the MD (p<0.05) and DDD (p<0.05) groups, but only the MD group was comparable to the control group after treatment. Pre- and post-rehabilitation chewing cycles along the frontal plane on both sides in the MD group were similar to the control group. Considering the majority of the improvements in the diagnostic measures, patients with MD and DDD may benefit from occlusal splint therapy.Öğe Comparison of Alternative Adhesive Cementation Concepts for Zirconia Ceramic: Glaze Layer vs Zirconia Primer(Quintessence Publishing Co Inc, 2012) Cura, Cenk; Oezcan, Mutlu; Isik, Guel; Saracoglu, AhmetPurpose: Zirconia-based ceramics offer strong restorations in dentistry, but the adhesive bond strength of resin cements to such ceramics is not optimal. This study evaluated the bond strength of silane/adhesive/resin cement and zirconia primer/resin cement combinations on non-glazed and glazed zirconia surfaces before and after aging. Materials and Methods: Disk-shaped zirconia ceramic specimens (diameter: 8 mm; thickness: 2 mm) (N = 80, n = 10 per group) were randomly divided into 2 groups. While half of the specimens received one coat of glaze and were later finished by grinding, the other half was only ground using 1200-grit silicone carbide abrasives under water. The glazed specimens were then conditioned with 9.5% HF acid gel for 60 s, rinsed with water for 90 s, and neutralized. The glazed and non-glazed specimens were further divided into two groups. Two resin cements, namely, Variolink II and Multi link Automix were adhered onto the zirconia surfaces with their corresponding adhesive systems. In the Variolink II group, zirconia surfaces were silanized (Monobond-S), and adhesive resin (Heliobond) was applied and photopolymerized. In the Multi link Automix group, one coat of Metal/Zirconia Primer was applied with a microbrush, left to react for 180 s, and dried using oil-free air. Half of the specimens in each cement group were subjected to 5000 thernnocycles (5 degrees C to 55 degrees C) and the other half was kept in the dark for 24 h at 37 degrees C prior to testing. Specimens were mounted in the jig of the universal testing machine, and force was applied to the ceramic/cement interface until failure occurred (1 mm/min). After evaluating all debonded specimens under SEM, the failure types were defined as either "adhesive" with no cement left on the zirconia (score 0) or "mixed" with less than half of the cement left on the surface with no cohesive failure of the substrate (score 1). Data were analyzed using three-way ANOVA and Dunnett-T3 post-hoc tests. Results: Application of a glaze layer significantly improved the bond strength in the silane/adhesive/Variolink II group (p < 0.05), but no significant effect was found in the zirconia primer/Multilink Automix group (p > 0.05) (three-way ANOVA). Interaction terms were also significant (p < 0.05) (Dunnett-T3). Thermocycling did not decrease the results significantly in any of the groups (p > 0.05). Failure analysis revealed exclusively adhesive failures (score 0: 40 out of 40) in the non-glazed groups, but predominantly mixed failures (score 1: 34 out of 40) in the glazed groups. Conclusion: The silane (Monobond S)/adhesive (Heliobond)/Variolink II resin cement combination benefitted from glazing the zirconia surface, but the zirconia primer/Multilink Automix resin cement combination alone also provided sufficient bond strength to zirconia.Öğe An investigation of atomic force microscopy, surface topography and adhesion of luting cements to zirconia: effect of silica coating, zirconia primer and laser(Taylor & Francis Ltd, 2019) Yildirim, Bengisu; Kumbuloglu, Ovul; Saracoglu, Ahmet; Husain, Nadin Al-Haj; Ozcan, MutluThis study evaluated the effect various surface conditioning methods on the surface topography and adhesion of luting cements to zirconia. Zirconia blocks (N = 25) were randomly assigned to five groups according to the surface conditioning methods: (a) No conditioning, control (CON), (b) tribochemical silica coating (TSC), (c) MDP-based zirconia primer (ZRP), (d) coating with nano aluminum nitride (ALN) (e) etching with Er: YAG laser (LAS). The conditioned zirconia blocks were further divided into five subgroups to receive the luting cements: (a) MDP-based resin cement (Panavia F2.0) (PAN), (b) 4-META-based cement (Super Bond) (SUB), (c) UDMA-based (GCem) (GCE), (d) bis-GMA based (Bifix QM) (BIF) and (e) polycarboxylate cement (Poly-F) (POL). Cements were applied in polyethylene moulds (diameter: 3 mm; height: 2 mm). The bonded specimens were first thermocycled for 5500 cycles (5-55 degrees C) and then adhesive interface was loaded under shear (0.5 mm/min). The data (MPa) were analyzed using 2-way ANOVA, Tukey's and Bonneferroni tests (alpha = 0.05). Regardless of the cement type, TSC resulted in significantly higher bond strength (p < 0.05) (13.3 +/- 4.35-25.3 +/- 6.3) compared to other conditioning methods (2.96 +/- 1.5-5.4 +/- 5.47). Regardless of the surface conditioning method, no significant difference was found between MDP, 4-META and UDMA based cements (p > 0.05) being significantly higher than those of bis-GMA and polycarboxylate cements (p < 0.05). Failure types were frequently adhesive in all groups. Tribochemical silica coating provided superior bond results compared to other conditioning methods tested on zirconia especially in conjunction with UDMA- and 4-META-based resin cements.Öğe Masticatory Performance and Mandibular Movement Patterns of Patients with Natural Dentitions, Complete Dentures, and Implant-Supported Overdentures(Quintessence Publishing Co Inc, 2012) Toman, Muhittin; Toksavul, Suna; Saracoglu, Ahmet; Cura, Cenk; Hatipoglu, AnilThe aim of this study was to compare quantitatively the masticatory performance of patients with overdentures supported by two implants, conventional complete dentures, and natural dentitions. Each patient was asked to chew a gelatin cube. The collected remains of the test food (gelatine cube) were fractioned by a sieving procedure and weighed. Maximum mouth opening and masticatory area were measured using kinesiography. There were statistically significant differences among groups with respect to masticatory performance using a 3.15-mm-diameter sieve (P < .001) and 0.5-mm-diameter sieve (P < .001), masticatory area (P = .019), and maximum mouth opening (P < .001). Increasing retention of a mandibular complete denture with two implants improved masticatory performance. lot J Prosthodont 2012:25:135-137Öğe Pilot study of unidirectional E-glass fibre-reinforced composite resin splints: Up to 4.5-year clinical follow-up(Elsevier Sci Ltd, 2011) Kumbuloglu, Ovul; Saracoglu, Ahmet; Ozcan, MutluObjectives: This prospective clinical pilot study evaluated the performance of fibre-reinforced-composite resin (FRC) splints on mandibular anterior teeth. Methods: Between June-2003 and January-2008, 19 patients (7 females, 12 males, 45-72 years old) from a group of consecutive patients who completed periodontal therapy received E-glass FRC splints (everStick Perio, StickTech) in combination with two types of flowable and restorative resin-composites (Filtek Flow, Filtek Supreme, n = 11; Tetric Flow, Tetric-Ceram, n = 8). Only patients with vital teeth, presenting mobility of grade 3, having at least one canine with no mobility on both sides of the dental arch were assigned for a splint therapy. The patients were recalled for periodical follow-up controls first at 6 months and thereafter annually. The evaluation protocol involved technical failures [chipping, debonding or fracture (tooth/restoration)] and biological failures (caries)]. Periodontal pocket depth (PPD) and clinical attachment level (CAL) were measured 6 months after splinting and annually. Six sites were measured for each natural tooth at the mesiobuccal, buccal, distobuccal, distolingual, lingual and mesiolingual sites. Results: All splints were applied from canine to canine in the mandible. In total, 5 recalls were performed and no drop-out was experienced. One partial debonding of the FRC splint with Tetric Flow/Tetric-Ceram combination was observed after 40 months. No caries was found around any of the splints and no teeth had to be extracted until the final follow up. The splinted teeth were found to be vital in the vitality tests. Overall survival rate was 94.8% (Kaplan-Meier). The survival rate was not significantly affected by the composite type (Filtek-Flow/Filtek Supreme: 100%, Tetric Flow/Tetric Ceram: 96% (p = 0.92) [ Kaplan-Meier, Log Rank (Mantel-Cox) (CI = 95%)]. Hazard ratio for Tetric Flow/Tetric Ceram group was 0.05 (95% CI) and for Filtek Flow/Filtek Supreme group 0.00 (95% CI). Whilst overall PPD measurements of the dentition ranged between 6 and 12 mm, the CAL measurements ranged between 4.9 and 10 mm at baseline. The mean PPD for the splinted teeth decreased from 8.9 +/- 1.8 mm to 5.2 +/- 1.2 mm, and CAL decreased from 7.2 +/- 1.6 mm to 4.6 +/- 1 mm at the end point. Conclusion: Direct tooth splinting with E-glass FRC material performed successfully up to 4.5 years. Periodontal status of the splinted teeth showed decreased PPD and CAL. (C) 2011 Elsevier Ltd. All rights reserved.
