In vitro and In vivo Evaluationof Different Gingival Retraction Cords

Modern impression techniques used in restorative dentistry require displacementof gingival tissue to expose the subgingival finish lines on the tooth preparation. Many different medications are used on gingival retraction cords in order to minimize hemorrhage from the gingival sulcus during impression making. A common method of accomplishing gingival displacement is by packing cord into the gingival crevice. This is especially critical when using hydrophobic impression materials such as polyvinyl siloxanes. The purpose of this study was to determine whether any of the commonly used gingival retraction medications could inhibit the polymerization of polyvinyl siloxane impression materials when they are in direct contact with the setting material and to evaluate the clinical performance of retraction cords. Many gingival retraction cords in various shapes, sizes and medications are available on the market. The literature is replete with reports on the effects of medicated and non-medicated cords on impression and gingival tissue. In this study, the number of the criteria of evaluation was increased and both in vitro and in vivo studies were conducted together by three prosthodontists

Intraoral Repair of Metal Ceramic Restorations Following Preparation of the Endodontic Access Cavity (Case Reports)

The Manufacture of dental crowns and bridgework of porcelain fused to metal, a technique that results in highly functional and esthetic restorations, has been widely used for about 45 years. Bonded porcelain is exceptionally strong. However, the reasons for porcelain fracture may be multifactorial, and include where the bridge or crown substructure has been weakened by excessive occlusal adjustment or by the introduction of an endodontic access cavitiy. An esthetic and functional repair, wherever possible, has many advantages over time-consuming and expensive remakes of crowns and/or bridges. This report is a presentation of a simple method for both the dentist and the patient to repair a tooth with root canal treatment. In cases where the fracture is due to an endodontic access cavity, intraoral repair was performed using various porcelain repairing kits. The patients were recalled for follow up on a 3-month basis after treatment. This technique can be considered as a treatment of choice regarding the successful results

Intra-oral adhesive systems for ceramic repairs: a comparison

WOS: 000187413900003PubMed ID: 14763777The aim of this investigation was to compare the bond strength of restorative composite resin to dental ceramic conditioned with primers and adhesives of various commercial repair kits. Three intra-oral ceramic repair systems-Silistor (Heraeus Kulzer), Cimara (Voco), Ceramic Repair (Vivadent)-were used on all-ceramic (IPS Empress 2, Ivoclar-Vivadent) substrate. Shear bond strength of restorative composite resin to substrate was tested after thermocycling and without thermocycling (n = 10). Substrate surfaces of the specimen after loading were examined microscopically (SEM). The highest bond strengths in both water-stored (7.0 +/- 5.7 MPa) and thermocycled conditions (2.5 +/- 1.8 MPa) were obtained with the Vivadent repair system, while the lowest values were observed with the Cimara system (0.6 +/- 1.4 MPa and 0.0 +/- 0.0 MPa, respectively). Shear bond strengths appeared to be significantly affected by thermocycling (ANOVA, P< 0.05). It is concluded that there are significant differences in the bond strengths of resin composites and ceramic substrate. The roughened surface does not necessarily provide a better bond strength; the bond strength of composite decreases with storage in water and after thermocycling. Bond strength values were generally low for all of the tested materials

Amelogenesis imperfecta: The multidisciplinary approach. A case report

WOS: 000189088200002PubMed ID: 14765635Amelogenesis imperfecta is a hereditary developmental disorder of the dental enamel, in both primary and permanent dentition. The main clinical characteristics are extensive loss of tooth tissue, poor esthetics, and tooth sensitivity. Transmission of the gene takes place by either autosomal, dominant X-linked, or recessive modes. This clinical report describes a treatment sequence based on a multidisciplinary approach. A 21-year-old girl with hypoplastic amelogenesis imperfecta was referred to the Ege University School of Dentistry clinic. She was concerned about the poor appearance and sensitivity of her teeth. The patient presented with an anterior open bite, although orthodontic treatment had been completed previously. Periodontal gingivectomy of her posterior teeth followed by endodontic treatment where indicated was proposed. The prosthodontic treatment consisted of metal ceramic fixed partial dentures of precious alloy. At the end of treatment, function and esthetics were improved to a level acceptable to both the patient and the dental team

Clinical evaluation of different gingival retraction cords

PubMed ID: 17510720Objectives: Impression techniques in restorative dentistry require displacement of gingival tissues to expose subgingival finish lines on tooth preparations. Retraction cords are commonly used for this purpose. Some cord systems include various medicaments, which may remain in the sulcus after retraction procedures. The purpose of this study was to determine whether any of the commonly used gingival retraction medicaments could influence the surface characteristics of the impression material and to evaluate the clinical performance of retraction cords. Method and Materials: Sixteen cord systems in various shapes, sizes, and medications were used in this study. The clinical performances of cords were evaluated with a blind experimental study design, according to predetermined criteria. Results were analyzed by using chi-square test and ordinal logistic regression analysis (P < .05). Results: Statistically significant differences were found in all criteria among groups (P < .05). None of the materials investigated appeared to have any influence on the surface characterization of the polyvinyl siloxane impression material used. Better impression qualities were observed in groups with easy insertion, proper dilatation, less recurrent bleeding, and no remnants or fraying. Logistic regression analysis revealed that both retraction cord medicaments (odds ratio = 0.63, P = .00 < .05) and cord thicknesses (odds ratio = 2.09, P = .00 < .05) were important risk factors on the gingival margin quality. Conclusions: The applied gingival retraction cord systems had no influence on the surface characterization of the polyvinyl siloxane material tested. Gingival margin quality of the impression and clinical application procedures were affected by the retraction systems. Untreated, medium-braided, and epinephrine-impregnated cord systems were clinically successful. However, the potential systemic effects of epinephrine must be considered. © 2007 by Quintessence Publishing Co Inc

Shear bond strength of composite resin cements to lithium disilicate ceramics

PubMed ID: 15641979The aim of this study was to evaluate the shear bond strength of different commercial composite resin cement systems to lithium disilicate allceramic substrate. Five adhesive resin cement systems Panavia 21 and Panavia F (Kuraray), Variolink 2 (Ivoclar-Vivadent), RelyX Unicem Applicap and RelyX ARC (3M ESPE) were used on all-ceramic (IPS Empress 2; Ivoclar-Vivadent) substrate. Shear bond strength of adhesive resin cement to substrate was tested after thermocycling, or without thermocycling (n = 10). Substrate surfaces of the specimen after loading were SEM microscopically examined. The highest bond strengths in water stored conditions were obtained with RelyX ARC (28-7 ± 3.9 MPa), while in thermocycled conditions the highest bonding values were obtained with Variolink 2 (23.2 ± 7.5 MPa). The lowest values in both water stored (5.8 ± 4.0 MPa) and thermocycled (2.4 ± 2.9 MPa) conditions were obtained with Panavia 21. Shear bond strengths appeared to be affected significantly by thermocycling (ANOVA, P < 0.05). It was concluded that there were significant differences between the bond strengths of adhesive resin cements to lithium disilicate substrate

Effects of Sandblasting and Silicoating on Bond Strength between Titanium and Porcelain

WOS: 000443749400015PubMed ID: 30156204Purpose: The aim of this study was to evaluate the effects of the different sized alumina particles (50 and 150 mu m) and tribochemical silica-modified alumina particles (110 mu m) on titanium (Ti) surface to identify the most effective method of increasing the bond strength between porcelain and Ti. Materials and Methods: Thirty rectangular plates (15 mm x 50 mm x 1 mm) of commercially pure Ti (Cp Ti) Grade 5 (GC Dental Industrial Corporation, Tokyo, Japan) were divided into three groups for different surface modification procedures (n = 10). Ti bonder porcelain, opaque, and dentin layers were fired separately on Ti plates. All specimens were placed in a bending jig for four-point bending test. The load and crosshead displacement data were collected to calculate the strain energy release rate as a G value. Results: Lowest mean G values in J/m(2) were in the group sandblasted with 150 mu m Al2O3 particles (Group 2) (18.6 +/- 5), followed by the group sandblasted with 50 mu m Al2O3 particles (Group 3) (20.8 +/- 6.1) and the group sandblasted with 110 mu m silicoated Al2O3 particles (Group 1) (24.5 +/- 4.1). The one-way ANOVA and Bonferroni post hoc tests indicated that there was a statistically significant difference between Group 1 and Group 2 (P 0.05). Conclusion: The size of alumina particles is not a factor that is directly effective in enhancing the bond strength of Ti-porcelain systems. The bond strength of Ti-porcelain systems can be extremely improved by the application of sandblasting with silica-coated alumina particles

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

WOS: 000286333700002PubMed ID: 20878533Long-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

Determining candida spp. incidence in denture wearers

PubMed ID: 20143193The aim of this study was to determine Candida spp. incidence in the oral cavity of denture wearers and characterize predisposing factors in denture-related stomatitis (DRS). Three groups of denture wearers and a control group were evaluated for DRS according to Newton's classification. The amount of yeast in saliva and the presence of yeast on mucosal surfaces were determined by phenotyping methods, and the impact of some risk factors on candidal carriage was evaluated. The development of DRS is most common in complete prosthesis users. When the count of yeast in saliva is ?400 cfu/ml, the frequency of DRS is increased. In individuals who develop DRS, the most frequently encountered species that was identified as C. albicans. Prosthetic hygiene was related to the intensity of candidal growth and the development of DRS. C. albicans live as saprophyte in the oral cavity. But, it is capable of causing infection if there are predisposing conditions related to the host. Usage of removable prosthesis may cause these microorganisms to gain pathogenicity. © 2010 Springer Science+Business Media B.V