Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SILICATE CEMENT”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed1978

A new metal-ceramic crown.

A new method of attaching porcelain to precious metals using tin oxide coatings is described. Platinum foil is bonded to aluminous porcelain and forms an inner protective skin, thereby reducing the formation of microcracks and increasing the strength of the crown. An improvement in translucency of the crown is obtained by using thick layers of porcelain, and the technique still allows the use of a porcelain butt fit at the critical labiocervical margin.

Aluminum Silicates↗
PubMedDate not supplied

In-vivo evaluation of a feldspathic ceramic system: 2-year results.

OBJECTIVES: The aim of this clinical study was to evaluate feldspathic ceramic inlays by clinical criteria and quantitative margin analysis, and to compare clinical performance with the quantitative margin analysis results. METHODS: Fifty fibre-reinforced feldspathic ceramic inlays were placed in box-shaped, Class II preparations with all margins located in enamel. A low-viscosity type dual-curing resin luting material was used for luting. The inlays were evaluated clinically according to modified US Public Health Service criteria after 2 days, 1 year, and 2 years. In addition, quantitative margin analysis was performed under a scanning electron microscope using an image analysing system. RESULTS: Clinically the inlays performed very well after 2 years, showing no changes in colour, no recurrent caries and no marginal discolouration. Because of the wear of the composite resin luting material, margins were perceptible with an explorer in 54% of the cases after 2 years. Quantitative margin analysis showed significantly (P < or = 0.05) more marginal gaps at the composite/ceramic interface compared with the enamel/composite interface at each evaluation. There was a significant increase in marginal gaps at both interfaces during the first year, whereas marginal gaps at the composite/ceramic interface did not increase significantly during the second year. Quantitative margin analysis showed that both time and interface had a significant influence on marginal gaps. CONCLUSION: Quantitative margin analysis should be included in clinical long-term trials on this type of restoration to recognize possible deficiencies in ceramic, composite resin luting material, and the luting interfaces.

Adult↗
PubMed1996

Laboratory evaluation of three visible light-cured resinous liners.

OBJECTIVES: The aim of the present study was to evaluate the composition and the laboratory performance of three visible light-cured resinous liners (Cavalite, Ionoseal and Timeline). METHODS: Monomers were separated from fillers and were analysed by HPLC. Set pastes were analysed by FTIR spectroscopy and diametral strengths and water solubility were measured. RESULTS: The monomers identified in the liners were BisEMA/2-HEMA (Cavalite), BisDMA/BisGMA (Ionoseal) and UEDMA (Timeline). Significant variations were found in the filler content but the mechanical response as assessed by the diametral tensile strength showed no statistical differences. The curing efficiency ranged from 24.2 to 31.0% (top surfaces) to 26.0-54.0% (bottom surfaces) of remaining C = C bonds. No positive correlations were found between curing efficiency and optical properties. The bond strength of the liners to dentine was negligible compared with that to composite. All the liners demonstrated extensive gap formation and debonding at the liner-dentine interfaces in marginal adaptation testing. Statistical differences were noticed in the water absorption and water solubility values of the products. Ionoseal showed extensive hydrolytic degradation compared with the other liners. No evidence of acid-base reaction was found in the set products.

Acrylic Resins↗
PubMed2006

Effect of ZnO addition on bioactive CaO-SiO2-P2O5-CaF2 glass-ceramics containing apatite and wollastonite.

Some ceramics show bone-bonding ability, i.e. bioactivity. Apatite formation on ceramics is an essential condition to bring about direct bonding to living bone when implanted into bony defects. A controlled surface reaction of the ceramic is an important factor governing the bioactivity and biodegradation of the implanted ceramic. Among bioactive ceramics, glass-ceramic A-W containing apatite and wollastonite shows high bioactivity, as well as high mechanical strength. In this study, glass-ceramics containing zinc oxide were prepared by modification of the composition of the glass-ceramic A-W. Zinc oxide was selected to control the reactivity of the glass-ceramics since zinc is a trace element that shows stimulatory effects on bone formation. Glass-ceramics were prepared by heat treatment of glasses with the general composition: xZnOx(57.0-x)CaOx35.4SiO(2)x7.2P(2)O(5)x0.4CaF(2) (where x=0-14.2mol.%). Addition of ZnO increased the chemical durability of the glass-ceramics, resulting in a decrease in the rate of apatite formation in a simulated body fluid. On the other hand, the release of zinc from the glass-ceramics increased with increasing ZnO content. Addition of ZnO may provide bioactive CaO-SiO(2)-P(2)O(5)-CaF(2) glass-ceramics with the capacity for appropriate biodegradation, as well as enhancement of bone formation.

Apatites↗
PubMed2005

Measurement of the thermal diffusivity of dental filling materials using modified Angström's method.

OBJECTIVES: A new measuring technique for the determination of thermal diffusivity is proposed. Using this technique, the thermal properties of a few different dental filling materials were measured. METHODS: The proposed method for measurement of thermal diffusivity is based on the classical Angström's method. The method exploits the propagation of a plane thermal wave generated by a Peltier's device in a cylindrical sample along its axis. The thermal diffusivity of the sample is calculated from the phase difference between harmonic components of temperatures measured at sample surfaces, perpendicular to the direction of thermal wave propagation. The estimated accuracy of measurement is typically about 10% for samples with low thermal diffusivity. The proposed method was used for the determination of thermal diffusivities of Achatit Bichromatic, Charisma and Dentimet dental filling materials. RESULTS: The measured thermal diffusivities were: 0.295(0.020)x10(-6)m(2)s(-1) for Achatit Bichromatic, 0.321(0.015)x10(-6)m(2)s(-1) for Charisma and 1.70(0.12)x10(-6)m(2)s(-1) for Dentimet. The thermal conductivities of these materials were also estimated. The results were compared with values obtained from independent constant flux measurements with marble as a reference material. SIGNIFICANCE: There are no standard techniques for the determination of the thermal properties of dental filling materials. Moreover, it is difficult to find the thermal diffusivity and the thermal conductivity of many of them. The method proposed in this paper allows the simple and accurate measurement of thermal diffusivity. Thermal parameters of dental filling materials should be compatible with the parameters of human teeth. Lack of thermal compatibility can cause not only patient discomfort but also mechanical stresses leading to microcracks.

Composite Resins↗
PubMed2004

Microleakage and SEM evaluation of fissure sealants placed by use of self-etching priming agents.

OBJECTIVES: This study evaluated the microleakage and internal seal of fissure sealants placed by use of self-etching priming agents in comparison to phosphoric acid etching of enamel. METHODS: Seventy-two caries-free extracted human molars were divided into six groups with 12 teeth each. Occlusal surfaces were cleansed by either pumicing (Groups I, III, V) or by 15-s air-abrasion treatment with 25 microm aluminum oxide particles (Groups II, IV, VI). Fissures were sealed with the self-etching priming systems, Clearfil Liner Bond 2 (Groups I, II) or Resulcin AquaPrime (Groups III, IV). In Groups V and VI, sealants were placed after phosphoric acid etching. Half of the teeth in each group were thermocycled. After staining with 0.5% methylene blue, the teeth were sectioned for evaluation of microleakage. Internal adaptation of the fissure sealants was analyzed by SEM on replicas of cross sections. RESULTS: Independent of the methods used for cleansing of the occlusal surfaces, fissure sealants in Groups I and II showed significantly more microleakage and less sufficient internal seal as compared to sealants placed in Groups III to VI. Sealants placed by Resulcin AquaPrime (Groups III, IV) leaked significantly more than sealants applied after phosphoric acid etching (Groups V, VI) of the enamel. However, statistical analysis (H-test) did not reveal significant differences concerning the internal adaptation of sealants placed in Groups III, IV, V and VI. CONCLUSIONS: Concerning the microleakage data, use of the self-etching bonding systems, Clearfil Liner Bond 2 and Resulcin AquaPrime, cannot be recommended for fissure sealing, since the sealing ability is less effective as compared to the conventional acid-etching technique.

Acid Etching, Dental↗
PubMed2005

Dentist-time expenditure for two different adhesive all-ceramic systems.

OBJECTIVES: The purpose of this clinical investigation was to compare a chair-side adhesive all-ceramic system to a laboratory processed adhesive all-ceramic system with respect to quality and time expenditure for the dentist. METHODS: The same dentist treated 10 patients, who were each to receive two large posterior single tooth restorations of similar location and extent. One restoration was made in the laboratory by using the IPS Empress system [LAB], the other one was done chair-side by utilizing the Cerec system [CHAIR]. The time expenditure was measured for [LAB] and [CHAIR] and compared by the Wilcoxon signed rank test. The restorations were also evaluated according to the USPHS criteria. RESULTS: The mean time expenditure for the dentist with low-level assistance was 111:03 min [S.D.+/-24:09 min] for [LAB] and 115:31 min [S.D.+/-15:54 min] for [CHAIR]. Time expenditure with medium level assistance for the operator was 100:53 min [S.D.+/-23:59] for [LAB] and 105:50 [S.D.+/-15:28] for [CHAIR]. Assuming a high level of assistance, the mean time values were 53:11 min [S.D.+/-14:29] for [LAB] and 54:29 min [S.D.+/-09:21] for [CHAIR]. The baseline investigation according to the modified USPHS criteria did not reveal any differences between [CHAIR] and [LAB]. CONCLUSION: There were no statistical significant differences with respect to time expenditure or quality between [LAB] and [CHAIR] in this study.

Aluminum Silicates↗