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At least 109 records · Page 6Linked to original sources
PubMed2002

Clinical performance of resin composite restorations after 2 years.

The objective of this study was to evaluate the clinical performance of a packable restorative material, after 2 years in stress-bearing posterior cavities, according to the Ryge criteria. At least two Class 2 restorations (occluso-mesial, mesial-occlusal-distal, occlusal-distal) were placed in 46 patients (36.7 +/- 16 years). In each of the restorations (lot 221, metal matrix band system, glass ionomer-cement-base in 53% of the cavities, mostly no rubber dam) an adhesive system was used. Additionally, in each patient a flowable composite was used in one of the two fillings. After 2 years, 70% of the patients were available for reevaluation. Two restorations needed to be replaced as a result of postoperative sensitivities within the observation period, and one tooth received root canal treatment. All other restored teeth remained vital. One restoration with marginal discoloration received a score of Charlie; another with secondary caries received a score of Bravo. All the others revealed excellent and clinically acceptable results. No statistically significant difference (Chi-square-test) was observed between the two groups, with and without an additional flowable composite. After 2 years, the restorative material performed clinically well, with no observable fractures in the restoration.

Bicuspid↗
PubMed1987

The gingival marginal discrepancies of posterior composite restorations.

The purpose of this study is to assess the gingival marginal discrepancies of various types of composite restoratives using contoured matrix bands. The result of this study demonstrated that despite the great care taken during insertion and adaptation of the various composite restoratives, and inspite of bevelling of all cavosurface enamel margins, gingival deficiencies and/or excesses do still occur.

Bicuspid↗
PubMed1994

The centripetal build-up for composite resin posterior restorations.

The paper introduces a new technique for creating Class II posterior composite restorations--the centripetal build-up. This technique replaces the lost tooth structure from the periphery towards the center of the cavity, thereby achieving better marginal adaptation to the gingival floor. Since overfilling is rare, rotary finishing is minimized. This method allows the creation of long-term aesthetic posterior composite restorations, while utilizing conventional auxiliary (ie, metal matrix bands and wooden wedges) in operative dentistry. The learning objective of this article is to introduce this new technique to a wider segment of the dental profession.

Bicuspid↗
PubMed1993

The marginal adaptation of four different bonding agents in Class II composite resin restorations applied in bulk or in two increments.

Class II cavities with two retention grooves at the cervical wall, situated at the cemento-enamel junction, were restored with Palfique Light Cured composite resin and one of four different bonding agents and one of two composite resin application techniques. In 80 restorations, any gap present was disclosed by the penetration of a fluorescent resin into the air-filled gap. In another 80 restorations a toluidine blue solution was used to reveal gaps. Tokuso Light Bond and Superbond C&B had poor marginal adaptation: gap formation was observed in 90.0% and 57.5% of those restorations, respectively. In contrast, All-Bond had a 20.0% rate and Superbond D-liner had a 12.5% rate of restorations with failures, represented by very thin gaps in the outer part of the cervical wall. Bulk application of the composite resin material and light curing from the cervical and axial walls through a plastic matrix strip gave results comparable to those of a two-stage horizontal application technique with light curing from the occlusal area and a metal matrix band.

Boron Compounds↗
PubMed1993

Clinical evaluation of four dental amalgams over a three year period.

The aim of this study was to compare the clinical durability of four dental amalgams. In each of eighty-two patients one class 2 cavity was restored with Dispersalloy (Johnson and Johnson) which served as the control and all the other class 2 cavities were randomly restored with one of the following amalgams: Amalgaphase, Amalga 43 (Amalgam Alloys-South Africa) or Permite C (Southern Dental Industries). Matrix bands were placed and Kalzinol bases and Polyvar varnishes applied in all cavities. The amalgams were mixed according to the manufacturers' instructions, the cavities overpacked with amalgam, condensed by hand, carved and then burnished with a ball burnisher. Twenty-four hours later all restorations were polished and colour photographs taken. The restorations were evaluated using the Ryge and Snyder (1973) evaluation system, as well as comparison of the colour photographs. The Fisher's Exact Test was used for the statistical analysis. The two South African manufactured amalgams compared well with the two imported amalgams. However, at the end of the third year the score for the marginal integrity of Amalgaphase, one of the local products, was significantly different (p < 0.083) and inferior to that of the control, Dispersalloy. Evidence is produced to suggest that over a three year period Amalgaphase performed better than Dispersalloy, Amalga 43 and Permite C.

Dental Alloys↗
PubMed1992

Clinical evaluation of four dental amalgams over a two year period.

The aim of this study was to determine the clinical durability of two locally manufactured amalgams. In each of eighty-two patients one class II cavity was restored with Dispersalloy (Johnson and Johnson) which served as the control and all the other class II cavities were randomly restored with one of the following amalgams: Amalgaphase, Amalga 43 (Amalgam Alloys-South Africa) or Permite C (Southern Dental Industries). Matrix bands were placed. Kalzinol bases and Polyvar varnish were applied in all cavities. All amalgams were mixed according to the manufacturers' instructions. The cavities were overpacked with amalgam, and the amalgam condensed by hand, carved and then burnished with a ball burnisher. Twenty-four hours later all restorations were polished with a Shofu polishing system and colour photographs were taken. The restorations were evaluated using the Ryge and Snyder (1973) evaluation system, as well as comparison of the colour photos. The Fisher's Exact Test was used for the statistical analysis. During the second year there were no significant (p < 0.05) differences between the four brands of amalgam restorations except as regards the gloss category. The two South African manufactured amalgams compared well with the two imported amalgams. During the second year the marginal integrity and surface texture of Amalgaphase compared well with that of Permite C. Dispersalloy and Permite C showed more deterioration in anatomic form than the two South African amalgams. Amalgaphase was the only amalgam to show no bulk fracture within a period of two years. Amalgaphase performed better in the gloss category than the other three amalgams during the second year evaluation. According to the weighted product calculation Amalgaphase was the best amalgam followed by Dispersalloy, Amalga 43 and Permite C.

Dental Alloys↗
PubMedDate not supplied

Early fracture resistance of amalgapin-retained complex amalgam restorations.

Amalgapins are susceptible to early fracture during matrix removal and carving. The purpose of this study was to examine the early fracture resistance of amalgapin-retained restorations using a spherical amalgam alloy, an admixed amalgam alloy, a combination of admixed alloy over the spherical alloy, and a recently introduced modified spherical amalgam alloy. Four amalgapin channels with a diameter of 1.4 mm and depth of 2 mm were prepared in cylinders of Macor, a machinable ceramic material. The amalgapins were hand condensed, and the bulk of the restoration was mechanically condensed. In the group using the combination of alloys, 800 mg of spherical alloy was condensed into the amalgapins and over the floor of the preparation. The admixed alloy was then condensed over the spherical alloy to build up the bulk of the restoration. Using an Instron Universal Testing Machine, the restorations were tested to shear failure at an average of 15.8 +/- 1.3 minutes after the initiation of trituration of the amalgam alloy. A metal ring was placed around the restoration and pulled 90 degrees to the long axis to simulate matrix band removal. Data were analyzed using Kruskal-Wallis procedures. The fracture resistance of the spherical alloy group and the spherical/admixed group were significantly higher than admixed or Tytin FC. All fractures occurred in amalgam at the entrance to the amalgapin channel. The combination of spherical and admixed amalgam alloys in a restoration may reduce the potential for early dislodgment while allowing additional time for carving.

Dental Alloys↗
PubMed2003

Retraction of the Drosophila germ band requires cell-matrix interaction.

Integrins and laminins are important mediators of cell-matrix interactions in both vertebrates and invertebrates. Here, we show that germ-band retraction in the Drosophila embryo, during which the tail end of the embryo retracts to its final posterior position, allows the investigation of cell spreading and lamellipodia formation in real time in vivo. We demonstrate that alpha1, 2 laminin and alphaPS3betaPS integrin are required for the spreading of a small group of cells of the amnioserosa epithelium over the tail end of the germ band. We further implicate a role for this spreading in the process of germ-band retraction.

Animals↗
PubMed1990

Endochondral calcification by hypertrophic chondrocytes in the Meckel's cartilage grafted into the isogenic mouse spleen.

We found that when the midsection of Meckel's cartilage bars obtained from mice on the eighteenth day of gestation were grafted into isogenic mouse spleen, chondrocytes induced an endochondral calcification. Concurrent with the onset of calcification throughout Meckel's cartilage matrix, periodic banded thick collagen fibrils and matrix vesicles were observed around the chondrocytes. Although most of the chondrocytes prior to grafting were hypertrophic cells, they survived for seven days in the splenic tissue and had well-developed secretory organelles. The cells which were surrounded by calcified matrix were relatively small, spherical, and showed a morphology closely resembling that of osteocytes. These findings suggest that the life span of hypertrophic chondrocytes is influenced by the microenvironment of the spleen.

Animals↗
PubMed1983

Presence of oligoclonal immunoglobulin G bands and lack of matrix protein antibodies in cerebrospinal fluids and sera of ferrets with measles virus encephalitis.

Young adult ferrets were immunized with measles vaccine and 5 to 6 weeks later inoculated intracerebrally with Vero cells persistently infected with cell-associated strain D.R. of measles virus isolated from a patient with subacute sclerosing panencephalitis. Of nine ferrets which survived the infection for 3 weeks or longer, five showed neurological signs. At the time of death they had widespread inflammation in their brains, and cell-associated virus was isolated from three ferrets sacrificed from 5 weeks to 7 months after inoculation. Four ferrets did not develop clinical signs, but two of these had mild inflammation in the brain 7 months and 2 1/2 years after inoculation, respectively. Cerebrospinal fluids drawn by cisternal puncture from infected ferrets at the time of sacrifice had neutralizing titers against measles virus similar to the titers found in sera, but antibody against the measles virus matrix protein was not detectable. Cerebrospinal fluid showed increased immunoglobulin G (IgG) and had distinct measles virus-specific oligoclonal IgG bands. The intensity of the bands correlated with the neutralizing titers of the fluids. These results confirm and extend earlier findings and indicate that persistent measles virus infection in ferrets is similar to human subacute sclerosing panencephalitis and can be used to study certain aspects of persistent brain infections leading to subacute encephalitis.

Animals↗
PubMed1988

Studies on the interaction of matrix-bound inhibitor with Band 3, the anion transport protein of human erythrocyte membranes.

The effect of temperature and chemical modification on the interaction of the human erythrocyte Band 3 protein (the anion transport protein) with 4-acetamido-4'-isothiocyanostilbene 2,2'-disulfonate (SITS; Ki = 10 microM)-Affi-Gel 102 resin was studied. Band 3 binds to the affinity resin in two states; weakly bound, which is eluted by 1 mM 4-benzamido-4'-aminostilbene 2,2'-disulfonate (BADS; Ki = 2 microM), and strongly bound, which is eluted only under denaturing conditions by 1% lithium dodecyl sulfate (LDS). At 4 degrees C, most of band 3 was present initially in the weakly bound form and very little in the strongly bound form. With longer incubations at 4 degrees C, the weakly bound form was slowly converted to the strongly bound form. At 37 degrees C, most of Band 3 was rapidly converted to the strongly bound form, with some Band 3 still remaining in the weakly bound form. Band 3 dimers, labelled with 4,4'-diisothiocyanostilbene 2,2'-disulfonate (DIDS) in one monomer, did bind to immobilized SITS but did not become tightly bound upon incubation at 37 degrees C. Since the covalent attachment of DIDS to one monomer prevented the adjacent monomer from becoming tightly bound to immobilized SITS ligand, this observation suggests that the inhibitor-binding sites of the two adjacent monomers must be interacting with each other. When the inhibitor site of Band 3 was selectively modified by citrate in the presence of 1-ethyl-3-(3-azonia-4,4-dimethylpentyl)carbodiimide (EAC), Band 3 bound to the resin was more easily eluted by BADS, suggesting reduced affinity for immobilized SITS. However, citrate-modified Band 3 did become tightly bound upon incubation at 37 degrees C.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2005

Charge-transfer-type fluorescence of 4-(1H-pyrrol-1-yl)benzonitrile (PBN) and N-phenylpyrrole (PP) in cryogenic matrixes: evidence for direct excitation of the CT band.

The fluorescence spectrum of PBN in a neat argon matrix is excitation-wavelength-dependent: at short excitation wavelengths, it consists of dual emission assigned to a charge-transfer (CT) state and a much weaker band assigned to the locally excited (LE) state. The CT emission is broad and almost completely devoid of vibrational structure, whereas the LE band is characterized by vibrationally resolved emission. At long excitation wavelengths, only CT emission is observed, indicating that the CT state is populated directly by light absorption and not via the LE state. Comparison with jet-cooled spectra of the bare molecule allows the unambiguous assignment of the LE spectrum and the location of the 0,0 band. The matrix LE emission spectrum is blue-shifted with respect to that of the gas phase, showing that the dipole moment of the LE state is smaller than that of the ground state. The fluorescence spectrum of PBN in an argon matrix does not change appreciably when acetonitrile (AN) is added to the matrix, in contrast to the case of N-phenylpyrrol (PP) (Schweke, D.; Haas, Y. J. Phys. Chem. A 2003, 107, 9554), for which addition of AN results in the appearance of two well separated emission bands. The different photophysical behaviors of PP and PBN in an argon matrix (and in supersonic jets) are analyzed by a simple model that considers the restriction of large-amplitude motions in the matrix. The implications of these low-temperature studies for understanding the properties of these systems in liquid solution are discussed.

Journal Article↗