Publications by authors named "Fatih Tulumbaci"

7 Publications

  • Page 1 of 1

Accelerated Calcium Phosphate Mineralization by Peptides with Adjacent Oppositely Charged Residues.

ACS Biomater Sci Eng 2020 07 29;6(7):3791-3798. Epub 2020 Jun 29.

Department of Clinical Sciences, School of Dentistry, Ankara Yildirim Beyazit University, Ankara 06760, Turkey.

Calcium phosphate mineralizing peptides are of special importance for dental and orthopedic applications, such as caries remineralization and improved osteointegration. Uncovering the mechanism of action for such peptides is an ongoing challenge with the aim of a better fundamental understanding of biomineralization processes and developing optimized peptides for clinical use. It has recently been reported that "adjacent oppositely charged residue" motifs are found abundantly in cation binding, inorganic surface binding, or biomineralization-related proteins and may play a key role in the biomineralization events. Despite their medical importance, the role of these motifs has not yet been investigated on calcium phosphate mineral systems. To investigate this, we have designed peptides with different structural properties and different numbers of adjacent oppositely charged residues. We have evaluated their effects on calcium phosphate mineralization kinetics and mineral properties. The kinetics of the mineralization increased proportionally with an increasing number of adjacent oppositely charged residues. Two peptides with relatively high structural stability and two adjacent oppositely charged residues resulted in faster mineralization and more crystalline mineral compared to a peptide with a higher structural degree of freedom that contained only acidic residues. The fastest mineralization and the highest mineral crystallinity were obtained with a peptide containing the highest number of adjacent oppositely charged residues and highest structural degree of freedom. Our findings and observations from previously identified natural or designed peptides indicate that, in addition to structural instability, adjacent oppositely charged residues play a role in the cation binding, inorganic surface binding, and biomineralization of peptides and require further investigation. Lastly, the peptide identified in this study is an agent with potential medical applications involving the treatment of mineralized tissues.
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July 2020

Peptide-assisted pre-bonding remineralization of dentin to improve bonding.

J Mech Behav Biomed Mater 2021 01 5;113:104119. Epub 2020 Oct 5.

Department of Pediatric Dentistry, School of Dentistry, Ankara Yildirim Beyazit University, Ankara, Turkey.

Bonding with dentin is a complex process involving physical and chemical adhesion where the adhesive must be able to penetrate and envelop collagen fibers. Acid etching clears the dentin of debris, which prevents adhesives to interact with dentin. However, it also demineralizes the outermost surface of dentin and exposes collagen fibers. The mineral-free collagen is susceptible to collapse after drying and to proteolytic or microbial attack, ultimately impairing the bonding with dentin. To address this, we have attempted a pre-bonding rapid remineralization approach to recover the mineral content of etched dentin. We have used a mineralization-promoting peptide and high calcium/phosphate concentration to achieve this in a clinically applicable timeframe. Partial remineralization was confirmed via SEM and XRD analyses. The mechanical properties and the stability of the partially remineralized dentin were investigated via microhardness, collagen hydrolysis and shrinkage tests. The bonding properties were investigated via shear bond strength (SBS) and microleakage tests. Pre-bonding remineralization of dentin with peptide for 10 min significantly increased the stiffness, resistance to hydrolysis and reduced shrinkage due to drying. SBS was increased with both an etch&rinse and a self-etch adhesive. However, pre-bonding remineralization resulted in reduced microleakage only with the etch&rinse adhesive. The described method is readily applicable to clinic since it is expected to add only 10 min to the procedure. Future in situ and/or in vivo studies will help to confirm the benefits observed in this in vitro study and allow optimize the parameters of the method.
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January 2021

Evaluation of different Apexification treatments of teeth with immature apices and apical periodontitis on the fractal dimensions of trabecular bone.

Aust Endod J 2021 Aug 9;47(2):163-169. Epub 2020 Sep 9.

Faculty of Dentistry, Department of Oral and Maxillofacial Radiology, Bolu Abant Izzet Baysal University, Bolu, Turkey.

The aim of the present study was to investigate in the fractal dimension (FD) time-dependent changes of periapical bone after two different apexification treatments in teeth with immature apices and apical periodontitis. This study included 55 cases treated with apexification. Cases were divided into two groups: a calcium hydroxide group and a mineral trioxide aggregate group. In each case, the lesion area was evaluated by fractal analysis on periapical radiographs obtained before and 1-year after treatment via Image-J program. The FD of each region of interest on the radiographs was calculated using the fractal analysis method. The data were statistically analysed. In both groups, the FD values increased compare to initial at 1-year follow-up after treatment (P < .05). There was no statistically significant difference between the groups in terms of the time-dependent increase in FD values (P = 0.118). In the present study, time-dependent changes in FD were independent of the apexification method.
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August 2021

In vitro remineralization of primary teeth with a mineralization-promoting peptide containing dental varnish.

J Appl Oral Sci 2020 Sep 7;28:e20200259. Epub 2020 Sep 7.

Ankara Yildirim Beyazit University, School of Dentistry, Department of Basic Sciences, Ankara, Turkey.

Mineralization-promoting peptides are attractive candidates for new remineralization systems. In previous studies, peptides have been applied as aqueous solutions, which is not a clinically relevant form.

Objective: This study aims to investigate the efficiency of a mineralization-promoting peptide, applied in varnish, on remineralizing artificial caries on primary teeth.

Methodology: 55 primary molars were collected. Specimens were immersed in a demineralizing solution for 7 days and then, divided into 7 groups: Baseline: No-remineralization, Placebo: Blank colophony, F: Colophony 5% fluoride, P: Colophony 10% peptide, P+F: Colophony 5% fluoride and 10% peptide, Embrace: Embrace™ varnish, Durashield: Durashield™ varnish. A mixture of 35% w/v colophony varnishes were prepared in ethanol and applied accordingly. Specimens were immersed in a remineralization solution for 4 weeks and it was evaluated using PLM and SEM. Lesion depth reduction was examined by one-way ANOVA.

Results: There was no significant difference in mean lesion depths between baseline (147.04 ± 10.18 μm) and placebo groups (139.73 ± 14.92 μm), between F (120.95 ± 12.23 μm) and Durashield (113.47 ± 14.36 μm) groups and between P (81.79 ± 23.15 μm) and Embrace (90.26 ± 17.72 μm) groups. Lesion depth for the P+F group (66.95±10.59 μm) was significantly higher compared to all other groups. All groups contained samples with subsurface demineralized regions. Number of subsurface demineralized regions were higher in fluoride-containing groups.

Conclusions: We conclude that the mineralization-promoting peptide (MPP3) is effective in this in vitro study and the peptide shows benefits over fluoride as it yields less subsurface demineralized regions.
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September 2020

Efficacy of different remineralization agents on treating incipient enamel lesions of primary and permanent teeth.

J Conserv Dent 2019 May-Jun;22(3):281-286

Department of Pediatric Dentistry, Faculty of Dentistry, Kırıkkale University, Kırıkkale, Turkey.

Aims And Objectives: The aim of this study was to compare the efficacy of different remineralization (RM) agents on RM of artificial caries by evaluating the density, light reflection, and the crystal size of the newly formed mineral in primary and permanent teeth.

Materials And Methods: Caries-free primary and permanent molars were divided into seven groups ( = 20) and treated with: G1 - Deionized water, G2 - Colgate Cavity Protection, G3 - Sensodyne Rapid Relief, G4 - GC MI Paste Plus, G5 - Clinpro Tooth Creme, G6 - Clinpro 5000, and G7 - Sensodyne Repair and Protect. Lesion depths were evaluated using laser fluorescence (DIAGNOdent), and polarized light microscopy (PLM), and the minerals were evaluated using X-ray diffractometry (XRD).

Results: The highest decrease in laser fluorescence readings was observed in G6 for both primary and permanent teeth. No significant difference was observed between G2, G4, G5, and G6 in permanent teeth and G4 and G6 in primary teeth ( > 0.05). In PLM analyses, lesions depths were found to be lower in G6 compared to the other groups. No significant difference was observed between G2, G4, and G6 ( < 0.05). XRD evaluation showed that the newly formed mineral in G6 was denser and highly crystallized compared to the other groups.

Conclusion: This study demonstrated that Clinpro 5000 is more efficient in remineralizing incipient enamel lesions compared to the other agents tested.
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August 2019

Shear bond strength of different restorative materials to mineral trioxide aggregate and Biodentine.

J Conserv Dent 2017 Sep-Oct;20(5):292-296

Vocational School of Health Services, Kırıkkale University, Kırıkkale, Turkey.

Significance Of Study: Mineral trioxide aggregate (MTA) and Biodentine (calcium silicate-based materials) have great importance in dentistry. There is no study comparing the bond strength of Biodentine and MTA for composite, compomer, and compomer or resin-modified glass ionomer (RMGIC). Although many advantages of Biodentine over MTA; in this study, MTA has shown better shear bond strength (SBS) to restorative materials.

Aim: Recently, a variety of calcium silicate-based materials are often used for pulp capping, perforation repair, and endodontic therapies. After those treatment procedures, teeth are commonly restored with composite resin, (RMGIC materials in pediatric dentistry. The aim of this study was to evaluate the SBS of composite resin (Filtek™ Z250; 3M ESPE, USA), compomer (Dyract XP; LD Caulk/Dentsply, USA), and resin-modified glass ionomer (Photac-Fil Quick Aplicap; 3M ESPE, USA) to white MTA and Biodentine.

Materials And Methods: Ninety acrylic cylindrical blocks were prepared and divided into two groups ( = 45). The acrylic blocks were randomly allocated into 3 subgroups; Group-1A: MTA + composite (Filtek™ Z250), Group-1B: MTA + compomer (Dyract XP), Group-1C: MTA + RMGIC (Photac-Fil Quick Aplicap), Group-2A: Biodentine + composite, Group-2B: Biodentine + compomer, Group-2C: Biodentine + RMGIC. The specimens were mounted in Universal Testing Machine. A crosshead speed 1 mm/min was applied to each specimen using a knife-edge blade until the bond between the MTA/Biodentine and restorative material failed. Failure modes of each group were evaluated under polarized light microscope at ×40 magnification.

Results: There was no statistically significant difference between MTA + Composite resin with MTA + Compomer; and MTA + RMGIC with Biodentine + RMGIC ( > 0.05). There were statistically significant differences between other groups ( < 0.05).

Conclusions: The results of the present study displayed that although many advantages of Biodentine over MTA; MTA has shown better SBS to compomer and composite resin materials than Biodentine.
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February 2018

Fracture Resistance of Incisal Fragments Following Reattachment With Different Techniques in Simulated Crown Fractures.

J Lasers Med Sci 2017 27;8(4):181-185. Epub 2017 Sep 27.

Kırıkkale University Faculty of Dentistry, Restorative Dentistry, Kırıkkale, Turkey.

The aim of the present study was to evaluate and compare the effect of acidetching and Er, Cr:YSGG laser treatment before the reattachment of incisal fragments in coronal fractures of permanent incisor teeth. Sixty-six sound human maxillary incisors were randomly divided into 3 groups (n=22). Teeth were embedded in self-cure acrylic resins by leaving one-third of the crowns out, and uncomplicated crown fractures were obtained using an Instron testing device. The fragments were reattached using 3 different procedures and a hybrid resin composite (Z250): Group I: Acid etching + Prime & Bond NT; Group II: Er,Cr:YSGG + Prime & Bond NT; Group III: Er,Cr:YSGG + Acid etching + Prime & Bond NT. The percentages of shear bond strengths were determined by comparing fracture strengths of sound and reattached teeth for 3 groups. All data were analyzed statistically with Kruskal-Wallis H test. Mean fracture strengths of the reattached fragments were between 51.02% and 62.93% of that of the sound teeth in all groups. Group I had significantly higher percentages of shear bond strength values (<0.05) when compared to group II and group III. No significant difference (>0.05) was found between group II and group III. The findings of the present study show that Er,Cr:YSGG laser irradiation prior to the reattachment of incisal fragments has a negative effect on fracture strength.
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September 2017