Publications by authors named "Ayhan Gurbuz"

12 Publications

  • Page 1 of 1

Fabrication of obturator prosthesis by fusing CBCT and digital impression data.

Int J Comput Dent 2018;21(4):335-344

This clinical report describes a digital workflow using an intraoral digital impression and cone beam computed tomography (CBCT) volumetric data to create a three-dimensional (3D) virtual model of the dentition, defect area, and soft and hard tissue of a patient who had undergone a hemimaxillectomy. Stereolithography (SLA) 3D printing technology was used to produce a resin mold, from which an obturator prosthesis was fabricated through a conventional technique.
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September 2019

Comparative effects of denture cleansers on physical properties of polyamide and polymethyl methacrylate base polymers.

Dent Mater J 2013 ;32(3):367-75

Department of Prosthodontics, Faculty of Dentistry, Afyon Kocatepe University, Afyon, Turkey.

The purpose of this study was to evaluate the effect of denture cleansers on the surface roughness, hardness and color stability of two polyamides (Valpast, Deflex), a butadiene styrene copolymer PMMA (Rodex), and PMMA polymer as a control group (Paladent). Each material was divided into 5 sub-groups (n=7) as two control and three test groups. Three test groups were immersed for 20 days in commercially available three denture cleansers (CO-Corega, PR-Protefix, VA-Valclean). Two-way analysis of variance and Tukey's post hoc HSD test were used to evaluate surface roughness and hardness data (α=0.05). ΔE, ΔL*, Δa*and Δb* mean values were used for ANOVA, Tamhane test was used as post hoc. Polyamides showed low hardness and high roughness before and after immersion. A significant decrease in hardness was observed for all resins except Rodex after immersion (p<0.05). The denture cleansers changed the roughness, hardness and color of some resins.
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http://dx.doi.org/10.4012/dmj.2012-110DOI Listing
May 2014

Effect of at-home whitening strips on the surface roughness and color of a composite and an ormocer restorative material.

J Prosthodont 2013 Jan 17;22(1):69-73. Epub 2012 Sep 17.

Department of Prosthodontics, Faculty of Dentistry, University of Ankara, Ankara, Turkey.

Purpose: Oxygenating agents like carbamide peroxide or H(2) O(2) are commonly used whitening agents. They have varying influence on the color and surface roughness of resin-based restorative materials and teeth. The aim of this study was to evaluate the effect of an at-home peroxide whitening agent applied through a whitening strip on the color and surface roughness of a nanofilled composite resin and an ormocer-based resin.

Materials And Methods: Disc-shaped (2 mm thick, 10 mm diameter) nanofilled resin composite (n = 10) and ormocer (n = 10) specimens were prepared. All specimens were treated with a whitening strip. Whitening procedures were performed applying a 6.5% hydrogen peroxide whitening strip (Crest White Strips Professional) for 30 minutes twice each day for a period of 21 consecutive days. During the test intervals, the specimens were rinsed under running distilled water for 1 minute to remove the whitening agents and immersed in 37°C distilled water until the next treatment. Surface roughness and color of the specimens were measured with a profilometer and a colorimeter, respectively, before and after whitening. Color changes were calculated (ΔE) using L*, a*, and b* coordinates. Repeated measures of variance analysis and Duncan test were used for statistical evaluation (α= 0.05).

Results: The average surface roughness of composite increased from 1.4 Ra to 2.0 Ra, and from 0.8 Ra to 0.9 Ra for the ormocer material; however, these changes in roughness after whitening were not significant (p > 0.05). Also, when two materials were compared, the surface roughness of restorative materials was not different before and after whitening (p > 0.05). L* and b* values for each material changed significantly after whitening (p < 0.05). ΔE values (before/after whitening) calculated for composite (11.9) and ormocer (16.1) were not significantly different from each other (p > 0.05).

Conclusions: The tested whitening agent did not affect the surface roughness of either resin-based restorative material. Both materials became brighter after whitening. The behavior of the materials in the yellow/blue axis was opposite to each other after whitening. Each material had clinically unacceptable color change after whitening (ΔE > 5.5); however, the magnitude of the color change of materials was similar (p > 0.05). According to the results of this study, with the use of materials tested, patients should be advised that existing composite restorations may bleach along with the natural teeth, and replacement of these restorations after whitening may not be required.
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http://dx.doi.org/10.1111/j.1532-849X.2012.00918.xDOI Listing
January 2013

Enhanced retention of a maxillofacial prosthetic obturator using precision attachments: Two case reports.

Eur J Dent 2012 Apr;6(2):212-7

Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, TURKIYE.

The majority of maxillary defects can be rehabilitated with conventional simple obturator prosthesis. However, inadequate retention, stability and support may be associated with the use of an obturator. Precision attachments have been used to retain obturators for some time. The use of precision attachments in a dentate maxillectomy patient can yield significant functional improvement while maintaining the obturator's aesthetic advantages. This clinical report describes the prosthetic rehabilitation of two maxillary defects with an obturator retained using extracoronal resilient precision attachments.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3327502PMC
April 2012

Effect of autoclave postpolymerization treatments on the fracture toughness of autopolymerizing dental acrylic resins.

J Appl Biomater Funct Mater 2012 Jun 26;10(1):37-42. Epub 2012 Jun 26.

Department of Prosthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon, Turkey.

Introduction: Microwave and water bath postpolymerization have been suggested as methods to improve the mechanical properties of heat and autopolymerizing acrylic resins. However, the effects of autoclave heating on the fracture properties of autopolymerizing acrylic resins have not been investigated.

Purpose: The aim of this study was to assess the effectiveness of various autoclave postpolymerization methods on the fracture properties of 3 different autopolymerizing acrylic resins.

Methods: Forty-two specimens of 3 different autopolymerizing acrylic resins (Orthocryl, Paladent RR and Futurajet) were fabricated (40x8x4mm), and each group was further divided into 6 subgroups (n=7). Control group specimens remained as processed (Group 1). The first test group was postpolymerized in a cassette autoclave at 135°C for 6 minutes and the other groups were postpolymerized in a conventional autoclave at 130°C using different time settings (5, 10, 20 or 30 minutes). Fracture toughness was then measured with a three-point bending test. Data were analyzed by ANOVA followed by the Duncan test (α=0.05).

Results: The fracture toughness of Orthocryl and Paladent-RR acrylic resins significantly increased following conventional autoclave postpolymerization at 130°C for 10 minutes (P<.05). However, the fracture toughness of autoclave postpolymerized Futurajet was not significantly different than its control specimens (P<.05). The fracture toughness of Futurajet was significantly less than Paladent RR and Orthocryl specimens when autoclaved at 130°C for 10 minutes.

Conclusions: Within the limitations of this study, it can be suggested that autoclave postpolymerization is an effective method for increasing the fracture toughness of tested autoploymerized acrylic resins.
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http://dx.doi.org/10.5301/JABFM.2012.9271DOI Listing
June 2012

Nerve damage assessment following implant placement in human cadaver jaws: an ex vivo comparative study.

J Oral Implantol 2014 Feb 8;40(1):76-83. Epub 2011 Dec 8.

1  Ankara University, Faculty of Dentistry, Department of Prosthodontics, Ankara, Turkey.

The present study compared the use of cone beam computerized tomography (CBCT) images and intra-oral radiographs in the placement of final implant drills in terms of nerve damage to cadaver mandibles. Twelve cadaver hemimandibles obtained from 6 cadavers were used. Right hemimandibles were imaged using peri-apical radiography and left hemimandibles using CBCT, and the images obtained were used in treatment planning for the placement of implant drills (22 for each modality, for a total of 44 final drills). Specimens were dissected, and the distances between the apex of the final implant drill and the inferior alveolar neurovascular bundle and incisive nerve were measured using a digital calliper. Nerves were assessed as damaged or not damaged, and the Chi-square test was used to compare nerve damage between modalities (P < 0.05). Nerve damage occurred with 7 final drills placed based on peri-apical radiography (31.8%) and 1 final drill placed using CBCT images (4.5%). The difference in nerve damage between imaging modalities was statistically significant (P = 0.023), with CBCT outperforming intraoral film in the placement of final implant drills ex vivo. In order to prevent nerve damage, CBCT is recommended as the principal imaging modality for pre-implant assessment.
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http://dx.doi.org/10.1563/AAID-JOI-D-11-00191DOI Listing
February 2014

Rehabilitation of a patient with mandibular resection using osteointegrated implants: a case report.

J Oral Implantol 2013 Oct 26;39(5):609-14. Epub 2011 Sep 26.

Ankara University, Ankara, Turkey.

This case report details a 65-year-old male patient who underwent mandibular resection and radiotherapy as treatment for squamous cell carcinoma of the right mandible. The patient was rehabilitated with an implant-supported fixed partial denture and a maxillary occlusal ramp. The patient has been wearing his prosthesis for 2 years with no complaints.
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http://dx.doi.org/10.1563/AAID-JOI-D-11-00150DOI Listing
October 2013

Surgical and prosthetic rehabilitation of edentulous adult cleft palate patients by dental implants.

J Craniofac Surg 2010 Sep;21(5):1538-41

Department of Oral and Maxillofacial Surgery, University of Ankara, Faculty of Dentistry, Ankara, Turkey.

Adult patients who did not receive proper treatment for cleft palate are challenging for clinicians in terms of prosthetic rehabilitation. Moreover, during the late stages of adulthood when patients become edentulous, prosthetic reconstruction becomes even more challenging. This clinical report describes the prosthetic rehabilitation of 2 edentulous geriatric patients with unrepaired cleft palate by placement of dental implants after closure of the oronasal communications.
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http://dx.doi.org/10.1097/SCS.0b013e3181ec6922DOI Listing
September 2010

Prosthetic rehabilitation of a patient with bilateral cleft lip and palate using osseointegrated implants and extracoronal resilient attachments: a case report.

Cleft Palate Craniofac J 2011 May 11;48(3):342-7. Epub 2010 Aug 11.

This case study reports on the prosthetic rehabilitation of a patient with an unrepaired bilateral cleft lip and palate using osseointegrated implants, extracoronal resilient attachments, a combination of metal-ceramic cement-retained fixed partial restorations, and removable prosthesis. Preoperative clinical examination of a 32-year-old woman with bilateral cleft lip and palate revealed a large oronasal communication, hyperplastic soft tissue surrounding the hard palate defect, and a severely resorbed alveolar ridge. A maxillary obturator prosthesis supported by implants and retained with an extracoronal resilient attachment was designed to cover the oronasal communication in the hard palate and fulfill the patient's functional and aesthetic requirements. The patient has been wearing the prosthesis for 1 year. Her speech quality has greatly improved, and her aesthetic and functional expectations have been met.
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http://dx.doi.org/10.1597/09-248DOI Listing
May 2011

Usage of fiber-reinforced resin instruments in interproximal surfaces.

Eur J Dent 2008 Apr;2(2):96-101

PhD, Department of Operative Dentistry, Faculty of Dentistry, Near East University, Mersin, Turkey.

Objectives: The aim of this study was to investigate the effects of fiber-reinforced resin burs on the surface roughness of a nanofilled composite.

Methods: Average surface roughness values (Ra, mum) were measured using a surface profilometer and surface textures after finishing procedures were evaluated using a scanning electron microscope (SEM). Thirty cylindrical specimens were prepared using sectional teflon molds. A nanofilled composite was chosen. After the preparation specimens were divided into three subgroups randomly. After profilometric measurements, representative samples of the mentioned finishing procedures were selected and SEM analyses were carried out.

Results: Mylar strip group was statistically different from the other two groups (P<.05). The smoothest surfaces occurred when composite resin samples were light cured against the strips. On the other hand there was no statistical difference between fiber-reinforced resin burs and Sof-Lex discs (P>.05). For fiber-reinforced resin burs scratches and pitting which may be due to plucking of the filler particles during finishing were observed on the surface topography of the composite resin material. On the other hand, for the Sof-Lex discs although scratches were noticed on the surface topography, no pitting was observed.

Conclusions: Fiber-reinforced resin burs can be preferred for the grinding of composite surplus in interproximal surfaces, where the use of Sof-Lex discs can be harmful to soft tissues.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2633163PMC
April 2008

Effect of airborne-particle abrasion on retentive strength in overtapered fixed prosthodontic restorations.

Quintessence Int 2008 Mar;39(3):e134-8

Department of Prosthodontics, Ankara University, Turkey.

Objective: To evaluate retentive strength and film thickness of complete metal crowns cemented to overtapered teeth with 3 different cements after the application of airborne-particle abrasion.

Method And Materials: Sixty extracted maxillary molar teeth were embedded in autopolymerizing resin. Crowns were prepared with 30-degree overtapered axial walls and a 1-mm shoulder margin using a water-cooled cylindrical airborne-particle abrasion device. Then, 60 complete crowns were made from a nickel-chromium alloy. Teeth and crowns were assigned to 2 groups, 30 to the control group and 30 to the experimental group to undergo airborne-particle abrasion. In the first part of study, 30 teeth from the experimental group were submitted to the silicon-replica technique and their buccolingual cross sections were measured so that cement film thickness could be measured before airborne-particle abrasion. Three measurements using a light microscope were made in 7 regions of each tooth. In the second part of study, complete metal crowns with and without airborne-particle abrasion were distributed into 3 groups with 10 teeth each to be cemented with zinc phosphate, polycarboxylate, or resin-modified glass ionomer. All specimens were subjected to a tensile bond test in an universal testing machine at a crosshead speed of 0.1 mm/min until failure. The results were then evaluated with Student t test at a 5% level of significance.

Results: The film thickness showed no statistically significant differences among groups (P > .05). There was a significant difference between the control and experimental groups, with an increase in all 3 cements after airborne-particle abrasion (P < .05). The highest retentive strength in the control group was found with resin-modified glass ionomer (141.4 +/- 56.7 N), but there was no significant difference between the resin-modified glass ionomer (141.4 +/- 56.7 N) and zinc phosphate (121.4 +/- 24.2 N) (P > .05). Retentive strength of polycarboxylate was the lowest (78.03 +/- 16 N) (P < .05). For the experimental group, the difference among the zinc phosphate (220.5 +/- 83.8 N), polycarboxylate (185.4 +/- 60.8 N), and resin-modified glass ionomer (228.9 +/- 62.4 N) was not statistically significant (P > .05).

Conclusion: Airborne-particle abrasion had a positive effect on the retention of complete metal crowns when the crowns were cemented with zinc phosphate cement, polycarboxylate cement, or resin-modified glass-ionomer cement.
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March 2008

Nasal prosthesis rehabilitation: a case report.

Quintessence Int 2004 Sep;35(8):655-6

Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey.

A nasal prosthesis can reestablish esthetic form and anatomic contours for midfacial defects often more effectively than can surgical reconstruction. This case report describes the clinical and laboratory procedures for fabricating a nasal prosthesis.
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September 2004