The attritional wear of human enamel and four different composite resins for the veneering of crowns was evaluated in a dual-axis chewing simulator over up to 1200000 loading cycles. Enamel showed less wear than the composite resins. However, an ultrafine compact-filled composite resin (Targis) showed a wear not statistically significantly different from that of enamel. The other composite resins showed a statistically significantly higher wear than enamel regardless whether microfine, ultrafine midway-filled or ultrafine compact-filled.
This study showed a slower wound healing in the high-energy lased tissues. A similar healing in the low-energy lased tissues and in the incisions with the conventional scalpel was observed. The differences in the distribution of matrix proteins during healing and the coagulation of the tissues, which were exposed to low-energy laser treatment, might be the explanation for the minimal scarring, contraction, and pigmentation of the lased tissues as compared to conventional incisions.
Within the limits of this in vitro study, veneered densely sintered alumina adhesively fixed with dentine-like cement, successfully masks the shade of different metal or ceramic restorative materials.
Fibrin sealants are very useful in different surgical fields. Fixation of free gingival grafts, root coverage procedures, and other techniques increasing connective tissue attachment may be associated with the application of Tissucol in periodontology. The aim of this study was to evaluate the influence of the fibrin sealant in the extracellular matrix, as well as alterations of the connective tissue matrix during wound-healing processes. In the back dermis of 15 Net male rats, Tissucol was implanted after intraperitoneal anesthesia. The implant material was placed in subcutaneous pockets (2 cm in length) which were sutured with interproximal sutures (test and control pockets). At 4, 7, 14, 21, and 28 days after surgery, biopsies of the healed and surrounding tissues were taken, frozen in liquid nitrogen, and examined histologically and immunohistochemically with antibodies against collagen types I, III, IV, V, VI, and VII. The findings showed thick and thin collagen type I and III fibers, respectively, with different orientations localized around the implant material. An increased amount of blood vessels and capillaries (their basement membranes containing collagen type IV) was observed during wound healing which may be associated with the implantation of the sealant. Collagen type V fibers were localized from the first days to the 4th postoperative week and, without any inflammatory reaction (according to histologic staining), formed a fibrillar extracellular matrix with high collagenase resistance. Collagen type VI showed a microfibrillar pattern of distribution, and collagen type VII was localized in the dermo epidermo junction and very deep in the connective tissue in the form of anchoring fibers (only in the test group) during the 4 postoperative weeks of healing. The data showed that Tissucol is a biocompatible component which cannot produce any extensive inflammatory reaction in the matrix. New blood vessel formation, an epithelial-connective tissue interface with high stability, as well as matrix alterations with high resistance in the proteolytic enzymes (i.e., collagenases) can be induced in the connective tissue after use of a fibrin sealant. All of these characteristics may be of great importance in connective tissue healing in periodontal surgical procedures.
The purpose of this study was to demonstrate the localization of collagen types I, III, IV, V, VI and VII as well as the glycoprotein fibronectin in nifedipine-induced gingival overgrowth. The slices, after the use of indirect immunofluorescence (incubation with antibodies against these extracellular matrix components), showed a diffuse distribution with the anti-types I and III in the stroma and fluorescent staining of the basement membranes of the epithelium, blood vessels and nerves with collagen type IV antibodies. The increased number of vessels was localized near the surface of the lesion. Collagen type V - seen as a filamentous - and collagen type VI - as microfibrillar - components were also localized in the tissue, showing completely different patterns of distribution. Collagen type V appeared "crater"-like and type VI displayed a "honeycomb"-shaped structural model. The blood vessels were not stained but the area around their walls demonstrated an intense fluorescence with these antibodies. Collagen type VII showed a characteristic linear staining near to the epithelial basement membrane. In contrast to this, fibronectin localized with a varied intensity in the different areas of the tissues and presented a "cloud"-like structure. This shows differences between the matrix components in nifedipine-induced hyperplasia and confirms the heterogeneity of the matrix in health and in gingival alterations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.