Mübin Ulusoy

Molecular typing of Candida albicans strains isolated from denture wearers by repetitive sequence-based PCR

Long-term use of prosthesis is the most important risk factor for the colonization of Candida species on the mucosal surfaces, which can lead to the development of denture-related stomatitis (DRS). Some individuals wearing prosthesis develop DRS and others do not. C. albicans strains isolated from both groups were genotypically compared. The purpose of this study was to determine whether the strain causing prosthesis stomatitis was different from the other strains genotypically. The study included 90 individuals wearing different prostheses and 20 control individuals with natural teeth. In the study 109 C. albicans strains were used which were isolated from the saliva samples and the mucosal surfaces of the tongues and palates of 51 individuals and then defined phenotypically. Phenotypic diagnosis of the isolates was genotypically verified by using species-specific PCR. For molecular typing, repetitive extragenic palindromic sequence polymerase chain reaction (REP-PCR) was employed. The results of the study revealed that REP-PCR had the capability to separate 109 C. albicans strains and six reference strains into 44 genotypes. Whereas C. albicans strains showed heterogenic distribution, C. albicans strains isolated from the individuals suffering from prosthesis stomatitis showed no specific genotypes. REP-PCR is a simple, fast and low-cost method and helped work on a great number of samples.

Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography.

ABSTRACT Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (p<0.05), before and after cementation. Results Direct inlays presented statistically smaller marginal discrepancy values than indirect inlays, before (p=0.00001442) and after (p=0.00001466) cementation. Marginal discrepancy values were increased for all restorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner. Conclusions Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation.

Effect of different veneering techniques on the fracture strength of metal and zirconia frameworks.

PURPOSE To determine whether the fracture strengths and failure types differed between metal and zirconia frameworks veneered with pressable or layering ceramics. MATERIALS AND METHODS A phantom molar tooth was prepared and duplicated in 40 cobalt-chromium abutments. Twenty metal (IPS d.SIGN 15, Ivoclar, Vivadent, Schaan, Liechtenstein) and 20 zirconia (IPS e.max ZirCAD, Ivoclar) frameworks were fabricated on the abutments. Each framework group was randomly divided into 2 subgroups according to the veneering material: pressable and layering ceramics (n=10). Forty molar crowns were fabricated, cemented onto the corresponding abutments and then thermocycled (5-55℃, 10,000 cycles). A load was applied in a universal testing machine until a fracture occurred on the crowns. In addition, failure types were examined using a stereomicroscope. Fracture load data were analyzed using one-way ANOVA and Tukey HSD post-hoc tests at a significance level of 0.05. RESULTS The highest strength value was seen in metal-pressable (MP) group, whereas zirconia-pressable (ZP) group exhibited the lowest one. Moreover, group MP showed significantly higher fracture loads than group ZP (P=.015) and zirconia-layering (ZL) (P=.038) group. No significant difference in fracture strength was detected between groups MP and ML, and groups ZP and ZL (P>.05). Predominant fracture types were cohesive for metal groups and adhesive for zirconia groups. CONCLUSION Fracture strength of a restoration with a metal or a zirconia framework was independent of the veneering techniques. However, the pressing technique over metal frameworks resisted significantly higher fracture loads than zirconia frameworks.

Comparison of Marginal and Internal Adaptation of Heat-Pressed and CAD/CAM Porcelain Laminate Veneers and a 2-Year Follow-Up: Heat-Pressed and CAD/CAM Porcelain Veneer Adaptation

PURPOSE To compare marginal and internal adaptations of porcelain laminate veneers fabricated with heat-pressed and CAD/CAM techniques, and to evaluate the clinical performances 2 years after cementation. MATERIALS AND METHODS Thirty heat-pressed and 31 CAD/CAM porcelain laminate veneers were fabricated for 12 patients. Silicone replicas of each veneer were obtained. Replicas were sectioned into 4 parts to measure adaptations of the veneers. A stereomicroscope was used to measure from 3 locations of replicas for marginal, and 9 locations for internal adaptations at 40x magnification. Clinical evaluations were done at baseline and 6, 12, 18, and 24 months after cementation according to the modified United States Public Health Service (USPHS) criteria. Independent samples t-test compared the adaptation values between heat-pressed and CAD/CAM groups. Paired t-test was used to evaluate marginal and internal adaptations of each group. Differences between the modified USPHS criteria ratings of heat-pressed and CAD/CAM groups were determined by the Mann-Whitney U test. Kaplan-Meier analysis was used to analyze the survival ratings of the veneers (p < 0.05). RESULTS The mean marginal adaptation values of heat-pressed and CAD/CAM veneers were 295 and 314.98 μm, respectively, and there was no statistically significant difference (p = 0.541). Internal adaptation values of groups were not statistically different either (201.82 μm for heat pressed; 195.47 μm for CAD/CAM p = 0.734). When marginal and internal adaptation values were compared within groups, there were significant differences both for heat-pressed (p < 0.001) and CAD/CAM (p < 0.001). All veneers were rated 100% satisfactory during the 2-year period. CONCLUSION Within the limitations of this study, fabrication method, whether CAD/CAM or heat-pressed, had no effect on the marginal and internal adaptation of porcelain laminate veneers. The results showed that both fabrication techniques performed well after 2 years of clinical performance.

A Collapsible Partial Denture for a Patient with Limited Mouth Opening Induced by Scleroderma: A Clinical Report

A limited opening of the mouth is defined as microstomia. Microstomia is caused by burns, postoperative head and neck trauma, radiotherapy, or scleroderma. The prosthetic treatment of microstomia presents particular challenges, and patients often complain of an inability to insert or remove the prosthesis. The cause and severity of microstomia can influence the approach to treatment. Different treatment methods have been suggested, including the fabrication of two-piece partial dentures. This clinical report describes the construction of a sectional impression tray and a collapsed partial denture using a hinge attachment for a patient with microstomia.

Radiopacity of Luting Cements as a Potential Factor in Peri-implantitis: An In Vitro Comparative Study

The aim of this study was to establish the radiopacity of cements used in implant-retained fixed partial dentures with respect to implant material, enamel, and dentin. A sample of 10 specimens of 13 different cements, implants, enamel, and dentin were prepared. Radiographs of the specimens and aluminum step wedges were acquired. Mean gray values of specimens were measured using digital imaging software. Kolmogorov-Smirnov and Shapiro-Wilk normality tests and independent t test were used (P = .05). Implantlink Semi, Premier, and Dentotemp had the lowest radiopacity values; GC FujiTemp LT, Multilink Implant, Poly-F Plus, Cavex-Temporary, and Panavia SA showed the highest. Within the limitations of the study, cements containing zinc oxide and ytterbium-trifluoride can be recommended for cementation of implant-retained restorations.

Glass–ceramics bonding in geriatric patients: comparison with young teeth

OBJECTIVE The aim of the study was to assess whether in geriatric patients, the shear bond strength (SBS) of glass-ceramics differed when compared to young controls. BACKGROUND In the need of aesthetic restorations for geriatric patients, reliable bonding of glass-ceramics should be accomplished; however, glass-ceramics bonding on aged tooth structures is still unclear. MATERIALS AND METHODS Sixty extracted molars from young and geriatric patients [18-25 (Y), and 65-80 (O)] were cut buccolingually to prepare enamel (E) and dentin (D) surfaces. Both surfaces were randomly divided into three groups according to the resin cements: Variolink II (V); Superbond (S); and Clearfil Esthetic Cement (C) (n = 10). Disc-shaped glass-ceramics (IPS E-max Press) (n = 120) were prepared. Specimens were bonded and subjected to thermocycling. SBS test was performed using a universal testing machine (0.5 mm/min). After debonding, the surfaces were examined using stereomicroscope and scanning electron microscope. Data were statistically analysed with Kolmogorov-Smirnov, Levene, anova and Bonferroni tests (p = 0.05). RESULTS There were no significant differences between the old and young teeth surfaces. V showed the highest SBS [MPa(SD)] on both enamel and dentin [36.7 (6.5) (YE), 23.2 (13.2) (YD), 32.1 (16.2) (OE), 25.5 (8.6) (OD), respectively]. Significant differences were observed between resin cements (p < 0.05). The failure types were 43% adhesive between tooth and cement, 48% mix, 9% adhesive between cement and ceramic, regardless of cement type. CONCLUSION In geriatric patients, the shear bond strength of glass-ceramics did not differ when compared to that of young controls. On the dentin surface, etch-rinse resin cements appear to be more appropriate for glass-ceramics bonding.