Browsing by Author "Ozcopur, B."

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Effect of Different Mechanical Cleansing Protocols of Dentin for Recementation Procedures on Micro-Shear Bond Strength of Conventional and Self-Adhesive Resin Cements
(Elsevier Sci Ltd, 2013) Bavbek, A. B.; Goktas, B.; Sahinbas, A.; Ozcopur, B.; Eskitascioglu, G.; Ozcan, M.
Service life of debonded indirect dental restorations could be prolonged by recementation. This process requires removal of cement remnants from dentin. This study evaluated the effect of different mechanical cleansing protocols of dentin for recementation procedures on micro-shear bond strength (mu SBS) of conventional and self-adhesive resin cements. The labial surfaces mandibular incisors (N=200) were ground with a low speed saw to expose the corona] dentin. The teeth were randomly divided into two subgroups (n: 100 per group) and received either (a) conventional (Panavia F 2.0, Kuraray, PAN) or (b) self-adhesive (Clearfil SA, Kuraray, CSA) resin cement. Resin cements were condensed into polyethylene molds incrementally and photo polymerized using an LED polymerization unit. Specimens were stored in distilled water at 37 degrees C for 24 h and subjected to mu SBS (0.5 mm/min). Resin cement remnants on bonded dentin surfaces were removed using by (a) composite finishing bur (cb), (b) tungsten carbide bur (ob), (c) ultrasonic scaler tip (sc) or (d) pumice-water slurry (pw). Non-cleaned teeth acted as the control group (cn) (n: 20 per subgroup). After cleaning, the same cement type was rebonded simulating clinical recementation. Failure types were analyzed using optical microscope and Scanning Electron Microscope (SEM). Data (MPa) were analyzed using Wilcoxon Signed Ranks, Mann-Whitney U and Bonferroni tests (alpha=0.05). Overall, CSA (6.42 +/- 2.96) showed significantly lower results than that of PAN cement (7.88 +/- 3.49) (p < 0.05). All cleansing protocols (4.29 +/- 2.17 to 5.82 +/- 2.5) showed significantly lower results than that of the control group (9.84 +/- 4.88) for PAN cement. For CSA cement, all cleansing protocols presented non-significant results (4.25 +/- 2.74 to 6.44 +/- 2.4 MPa) compared to control group (p > 0.05) expect cb method (3.42 +/- 1.47) (p < 0.05). Remnants of cements were detected on dentin surfaces in all groups at varying degrees. SEM showed that while using pumice-water slurry was the least effective for PAN, tungsten carbide bur was the most effective for both cements. All other methods showed similar cleansing efficacy. None of the cleansing protocols yielded to complete removal of resin cement rest on dentin upon recementation for both cements tested. (C) 2012 Elsevier Ltd. All rights reserved.
The Effect of Different Posts on Fracture Strength of Roots With Vertical Fracture and Re-Attached Fragments
(Wiley-blackwell, 2010) Ozcopur, B.; Akman, S.; Eskitascioglu, G.; Belli, S.
P>The aim of this in vitro study was to test the effect of different post systems on fracture strength of roots with re-attached fragments. Root canals of eighty extracted single-rooted human teeth were instrumented (ProFile) and randomly divided into two groups. The roots in the first group were vertically cracked, and the fragments were re-attached using Super Bond C&B (Sun Medical, Tokya, Japan). The roots in the second group were kept sound. Obturation of the roots was performed with MetaSEAL (Sun Medical) and gutta-percha. Post spaces were prepared, and the roots were restored with one of the followings: UniCore (Ultradent), Everstick (Stick Tech), Ribbond (Ribbond), ParaPost (Coltene/Whaledent) (n = 10). Four mm high build-ups were created (Clearfil DC Bond Core; Kuraray, Tokyo, Japan). Compressive loading of the samples was performed after 24 h (1 mm min-1). Mean load necessary to fracture each sample was recorded (Newton) and statistically analysed (One-way anova, t-tests). ParaPost showed the highest fracture strength among the roots with re-attached fragments (P < 0.05). UniCore and ParaPost systems showed similar fracture strength in the sound roots (P > 0.05). Re-attached fragments significantly reduced the fracture strength of roots in UniCore group (P = 0.000). Ribbond post showed mostly repairable fractures. Metal post (ParaPost) showed the highest fracture strength in the roots with re-attached fragments; however, fracture pattern was 41% non-repairable. Re-attached fragments significantly reduced the fracture strength of the roots in UniCore group. Prefabricated posts showed similar fracture strength in the sound roots. Customized post systems EverStick and Ribbond showed mostly repairable failure after loading in sound roots or roots with re-attached fragments.
Periodontal Ligament Fibroblast Response To Root Perforations Restored With Different Materials - a Laboratory Study
(Wiley-blackwell, 2012) Hakki, S. S.; Bozkurt, S. B.; Ozcopur, B.; Purali, N.; Belli, S.
Aim To compare the effect of several materials on the attachment of periodontal ligament (PDL) fibroblasts to experimentally perforated root surfaces. Methodology Root specimens (size 5 x 5 mm) were obtained from extracted human molar teeth and perforations with a 1 mm diameter were created. One group was kept as a control and the rest were repaired with the following materials: Amalgam, Dyract, IRM, Super Bond C&B and Mineral trioxide aggregate (MTA). PDL fibroblasts were placed at a density of 8 x 104 cells on the root specimens, incubated on tissue culture inserts (48 h) and then transferred to 48 well-plates. MTT assays were performed at 48 and 96 h for PDL fibroblast survival. Cell attachment was observed using confocal microscopy on days 2 and 5. Total RNAs from the root specimens were isolated on day 5 and type I collagen (COL I) and Runt-related transcription factor 2 (Runx2) mRNA expressions were checked using Quantitative-Polymerase Chain Reaction (QPCR). For the MTT assay and QPCR, one-way analysis of variance (anova) and Tukey HSD multiple comparison tests were used to compare the groups. Results Mineral trioxide aggregate resulted in a significantly higher cell density (P < 0.001). Dyract, IRM and Super Bond C&B groups had a lower cell density when compared with the control and MTA groups at 48 h (P < 0.001). Confocal microscopy revealed that, among the experimental groups, the MTA group had the largest viable cell population over the restoration site when compared with the other materials; however, reduced cell attachment was noted in all groups when compared with the control. Increased Runx2 mRNA expressions were noted in MTA (P < 0.001) and IRM (P < 0.01) groups when compared with control and other tested materials. COL I transcripts were increased in IRM (P < 0.01), D, C&B and MTA (P < 0.001) when compared with the control. Conclusion Mineral trioxide aggregate provided a more favorable environment for PDL cell adhesion and growth.
The Response of Cementoblasts To Calcium Phosphate Resin-Based and Calcium Silicate-Based Commercial Sealers
(Wiley, 2013) Hakki, S. S.; Bozkurt, B. S.; Ozcopur, B.; Gandolfi, M. G.; Prati, C.; Belli, S.
Hakki SS, Bozkurt BS, Ozcopur B, Gandolfi MG, Prati C, Belli S. The response of cementoblasts to calcium phosphate resin-based and calcium silicate-based commercial sealers. International Endodontic Journal, 46, 242-252, 2013. Aim To investigate cell viability and gene expression of cementoblasts (OCCM.30) exposed to extractable components released by resin-based sealers with different chemical composition Hybrid Root Seal (HRS), SimpliSeal (SS), Real Seal (RS) and AH Plus (AH) and by a MTA-based sealers Tech Biosealer Endo (TBE). Methodology Discs of all materials were prepared and allowed to set in humid conditions at 37 degrees for 48h. The discs were then incubated for 72h at 37 degrees C to obtain material extracts (1/1) in DMEM. The extracts containing the components released by the sealers were filtered and other dilutions (1/2, 1/4) were prepared from the original solution (1/1). Original and diluted solutions were tested on the cementoblasts. Impedance-based real-time cell analysis (RTCA) was used to evaluate cell viability, quantitative real-time polymerase chain reaction (QRT-PCR) was used to examine the expression of mineralization-related genes (osteocalcin; OCN, Runt-related transcription factor-2; Runx2, collagen type 1; COL I, alkaline phosphatase; ALP). For statistical analysis, one-way analysis of variance (anova) and Tukey's honestly significant difference (HSD) tests were used. Results TBE (1/2), RS (1/2, 1/4), and HRS (1/2, 1/4) significantly decreased cell viability (P<0.001). AH (1/2, 1/4) and SS (1/2, 1/4) had similar cell viability to the control at 30h. All tested materials significantly decreased cell viability when compared to the control group except AH (1/2, 1/4) and SS (1/4) at 90h. All of the tested sealers reduced COL I mRNA expressions when compared to the control. SS was associated with significant increases in OCN and Runx2 mRNA expressions when compared to the control (P<0.001). Whereas all of the dilutions of TBE, RS and HRS significantly decreased BSP mRNA expressions (P<0,001), 1/2 and 1/4 dilutions of SS increased BSP mRNA expression (P<0,001). Except the 1/4 dilutions of AH and SS, all the sealer dilutions significantly reduced ALP mRNA expression in cementoblasts (P<0,001). Conclusions SimpliSeal and AH Plus resulted in more favourable response to cementoblasts because of their regulation potential on the mineralized tissue-associated protein's mRNA expressions.