Journal of Marmara University Dental Faculty最新文献

The purpose of this investigation was to determine the surface morphology and mineral content of periodontally diseased cementum surfaces following root planing and conditioning with either citric acid, tetracycline HCL and minocycline HCL. Mineral contents of cementum surfaces were determined with an electron probe. All 3 demineralizing agents caused the exposure of the collagen matrix on the root surface but citric acid was the more effective. Calcium (Ca) and phosphorus (P) showed higher values in citric acid and minocycline HCL treated cementum surfaces compared to nondiseased cementum surfaces. The Ca and P were found to be in similar proportions in the tetracycline HCL treated group and nondiseased cementum surfaces. Although citric acid is a strong demineralizing agent, our specimens' cementum surfaces to which citric acid was treated showed high Ca and P content. In our opinion this difference about the effects of demineralizing agents on the surface morphology and surface element content was found to be related to the facts that whether the total amount of hypermineralized cementum as removed or not with root planing and the lacking criteria to detects the amount of this removal. Our findings suggest that these demineralizing agents can demineralize cementum surface after root planing but can not remove all of the hypermineralized diseased cementum. For this reason, it may be stated that it is more important to remove the pathologically altered cementum than applying various chemical agents.

The aim of this research was to develop a method of local production of collagen graft materials which are presently imported. The following methods were used to produce collagen membrane and sponge from human placentas and rat tail tendons. Collagen type I was isolated from human placenta and rat tail tendon by acetic acid extraction and characterised by SDS-PAGE. The collagen sponge was prepared by dissolving the collagen in HCl. The resulting dispersion was poured into a glass container, freeze-dried and then cross-linked by immersion in glutaraldehyde solution. It was then washed with distilled water and freeze-dried again. The collagen membrane was also similarly prepared by dispersing lyophilized collagen in HCl but then mixed with glutaraldehyde, exposed to U.V. light and later air dried.

Four different glass-ionomer materials were evaluated for coronal microleakage in permanent lingual access restorations of endodontically treated anterior teeth. Forty extracted human anterior teeth were randomly divided into four groups following chemomechanical preparations and obturations with gutta-percha and sealer. Logobond, Aqua Ionobond, Ionoseal and Ketac-Cem were placed in 2 mm thickness over the gutta-percha obturation from cemento-enamel junction. Eight teeth were used as negative and positive controls. The teeth were thermocycled, coated with nail varnish and paraffin except around the access preparation. Next they were placed in dye and cleared to allow visualization of dye penetration. There was a tendency for the Ketac-Cem group to lack least but there were no statistically differences among the groups.

The prevention of degeneration and necrosis of the endodont is one of the main goals of dental treatment. Kerschbaum and Voss (1979, 1981) described that 15% of teeth showed negative results to sensitivity testing 10 years after crown preparation. Pulpal responses to dental treatment depend on many factors including thermal injury, transsection of the odontoblastic process, vibration, desiccation of dentin, pulp exposure, smear layer, remaining dentin thickness and used materials. The knowledge concerning endodontic reactions in short and medium term observation is mainly based on research by Klötzer and Langeland. Histological assessment of reactions is a well accepted method for biocompatibility testing (i.e. ISO/TR 7405). It is consistent to apply its principles to the evaluation of endodontic reactions of teeth with long term restorations. As pulpal injury is furthermore due to microleakage between filling material and the wall of the cavity the analysis of infected dentin tubules seems to be important. A consideration of the location of the tubules and of the severity of the invasion is necessary. Using a classification (grade 1-6) comprising the parameters of degenerative and regenerative reactions and bacterial invasion, 24 teeth restored with different types of fixed prosthodontic restorations were investigated. The restorations were between 0-6, 7-12 and 13-18 years in situ. Serial sections (5 microns) were stained with haematoxylin-eosin, azan, according to Goldner and J. Hopkins. 22 of 24 teeth showed typical degenerative reactions. Negative sensitivity testing occurred in teeth with no pain and no or partial necrosis. The histobacteriological assessment showed bacterial invasion of the dentin tubules of 21 teeth. From this investigation it was concluded that the proposed classification shows sufficient sensitivity for the evaluation of progressive endodontic changes of long-term restored teeth. Furthermore it was shown that bacterial invasion must be considered as a possible co-factor for the described degenerative character of the pulpal tissue.

Gingival crevicular fluid (GCF), reflects the immune and inflammatory reactions and is itself a location for specific host-microbe interactions that lead to periodontal diseases. Aspartate aminotransferase (AST) is one of the components of GCF that is released as a result of cell death. In this study, 40 periodontal sites in 10 early onset periodontitis patients before and after nonsurgical periodontal therapy, with and without local metronidazole administration, were first examined for the AST enzyme levels in GCF and then evaluated for microbiological and clinical variables. In each patient, 4 sites (one site/quadrant) with a probing depth of > or = 5 mm were selected and treated with separate treatment protocols. Certain microbial species including Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans(A. a.) were found more often and/or in higher levels in AST active sites (36/40 first measurement--9/36 second measurement), while other species (Streptococcus and Actinomyces) were found more often and/or in higher levels in AST inactive sites (4/40 first measurement--8/36 second measurement). Eight post-treatment AST active sites revealed 1.5 mm of attachment loss, whereas 8 post-treatment AST inactive sites showed 1.37 mm of attachment gain. AST activity and microbiological-clinical data presenting such an agreement suggests that, AST level assessment would be beneficial as an adjunctive method alongside other clinical criteria, in guiding the clinician in periodontal treatment.

The marginal integrity is an important factor for the long-term success of ceramic inlays. The long term clinical performance of porcelain inlays depends on a number of factors of which the marginal adaptation is of significant interest. The aim of this study was to determine the margin quality of adhesively luted sintered porcelain inlays both in vivo and in vitro. MOD cavities without bevels were prepared on 10 extracted human mandibular molar teeth. Using the Ducera inlay system, inlays were fired on refractory dies and luted with a dual-curing composite resin. After polishing, each, tooth was sectioned in buccal/lingual and mesial/distal directions and marginal adaptation was assessed microscopically. The mean marginal gap of 78.77 +/- 14.85 microns recorded for occlusal margins was significantly smaller than that of 128.85 +/- 34.34 microns seen at the approximal margins. For in vivo evaluation, 25 fired porcelain inlays, including 7 onlays, were placed in Class II cavities. The assessment of the marginal adaptation of inlays was made according to the scaling system used by Aberg et al. (Acta Odontol Scand 1994; 52:140-149). In 19 of the clinical cases, the restoration was contiguous with the existing anatomic form. Both in vivo and in vitro evaluations showed the margin quality of porcelain inlays to be high.

Unlabelled: The purpose of this paper is to describe the subgingival placement of a resin-ionomer for several restorative procedures, namely, root resorption, endodontic perforation, and root fracture. After endodontic therapy, a combination scallop flap (in attached gingiva)-full thickness flap (at affected tooth only) was raised to gain access to the lesion and root defect. The root defects were prepared with ultra-sonic instruments under an operating microscope and the preparations treated with Tenure Dentin Conditioner (DenMat Corporation, Santa Maria, CA). The preparations were washed and lightly air-dried, and the Tenure All-Purpose Bonding System (Den Mat Corporation, Santa Maria, CA) was placed in the prepared areas. Geristore resin-ionomer (DenMat Corporation, Santa Maria, CA) was then syringed into the preparations and either light-activated or allowed to undergo a chemical set. Once set, the material was finished with fine diamonds under water spray. The flap was then sutured to place with Gore-Tex sutures when a non-resorbable Gore-Tex membrane (Gore Corporation, Flagstaff, AZ) was used or 4-0 nylon sutures when resorbable Guidor membranes (Butler Company, Bensenville, IL) were used. The sutures were removed after two days. The patients were observed weekly for the first month and then monthly until released. No untoward effects have been observed during the time frame of this project. All of the cases have been responding satisfactorily.

Clinical significance: The cases presented indicate that a resin ionomer, Geristore, may be used as a subgingival restorative, and may be placed in lesions thought to be unrestorable. Thus, teeth may be saved that were previously designated to be extracted.

In this preliminary study the salivary sialic acid levels in 56 randomly selected cancer patients of different ages were compared with those of 70 healthy controls of similar age distribution. The cancer patients consisted of 25 women and 31 men. Twenty were suffering from lung cancer. Unstimulated whole saliva was collected by expectoration. The mean sialic acid levels were 185 +/- 22.8 mg/dl in the cancer group and 6.2 +/- 3.72 mg/dl in the controls and the difference between them was significant (p < 0.0001). The subjects were also grouped according to age and cancer type. However there were no significant differences in sialic acid levels between these.

The aim of this work was to investigate the local effects of 1:25 dihydroxychole-calciferol, one of the most potent osteoclastic activity stimulants. Tests were conducted on 32 Wistar albino rats divided into 3 groups: an experimental (appliance + drug, n = 11), control (appliance only, n = 11) and a no therapy group (n = 10) which was used for purposes of interpreting histological findings in the others. A significantly higher area of unilateral apposition, relative to the control group, was observed in the experimental group local to the area of administration of the 1:25 D.

A brief description of the phenomenon of nonenzymatic glycosylation will be presented, some examples given from the literature and then a brief summary of the results of laboratory research conducted in this area by myself and coworkers since 1981. Excessive glycosylation causes undesirable changes in proteins. Such glycosylation also occurs to collagen in oral tissue. In a study on induced experimental diabetes in rats we observed a defective platelet aggregation curve for gingival collagen. Glycosylation of proteins is known to result in functional defects, for example hemoglobin acquires an increased affinity for oxygen. Glycosylation of rat and bovine lens crystallins has been reported as being an important genesis of cataracts in diabetes. Increased glycosylation of submandibular collagen has been shown to occur in diabetes. However collagen from normal subjects has also been found to show an age related advanced glycosylation end product pigment. Increased platelet membrane protein glycosylation has been reported and the hyperaggregation typically observed in these cases thought to be due to glycosylation. The presence of red cell membrane proteins has also been reported and the impairment of red cell function in diabetes has been reported in cases of excessive glycosylation. According to some investigators cataract formation is prevented by some specific drug which inhibits the glycosylation of lens crystallins. Vitamin C has lowering effects on nonenzymatic glycation. Dentists should take into account the possibility of glycosylation of oral proteins such as collagen in cases of impaired gingiva tooth connection.