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PubMed2003

Enamel demineralization inhibition by cements at orthodontic band margins.

PURPOSE: To examine the demineralization inhibition effects of glass ionomer cement and polyacid-modified resin-based composite cement, in comparison to non-fluoride releasing zinc phosphate cement. METHODS: Twenty-seven extracted molars were obtained and randomly assigned to three groups. An orthodontic band was sized and cemented using one of three cements. The teeth were painted with an acid-protective varnish, excluding a 1 mm area gingival to the orthodontic band. The teeth were placed in separate closed environments of a non-fluoridated acid challenge to induce demineralization for 5 days. The teeth were then sectioned two times buccolingually and two times mesiodistally. The sections were photographed with polarized light microscopy in an imbition media of water. The body of each lesion was measured with a computerized imaging system. The areas of the lesions, from each cement group, were compared. RESULTS: An analysis of variance (ANOVA) indicated significance in variance among groups (P < 0.001). Results of a multiple comparison analysis demonstrated significantly less demineralization adjacent to the glass ionomer cement group compared with the polyacid-modified resin cement group and non-fluoride releasing zinc phosphate control group (P < 0.05). There was no significant difference in adjacent demineralization inhibition between the zinc phosphate cement group and polyacid-modified resin cement group (P < 0.05).

Analysis of Variance↗
PubMed2000

Mechanical properties of hydroxyapatite reinforced poly(ethylmethacrylate) bone cement after immersion in a physiological solution: influence of a silane coupling agent.

PEMA-based bone cement has previously been shown to possess many advantages over traditional PMMA cements. One of these is the option of adding up to 40 wt % HA without a decrease in static mechanical strength, thus providing the potential for enhanced bioactivity. Bone cement, in vivo, is subjected to an aqueous environment and therefore, it is important to understand the influence of this upon the mechanical integrity of experimental cements. In this current investigation the static and dynamic properties of PEMA cement, with and without 30 wt % untreated and silanated HA, were examined after periods of immersion in Ringer's solution. A commercial PMMA cement was also tested in a similar manner. Relatively small changes in static mechanical properties were observed after 12 weeks storage for the PEMA cements, the largest change being for the PEMA cement reinforced with silanated HA. The PMMA cement exhibited the largest change in static strength with a decrease of 16.6%. In contrast to these results, the fatigue properties of the PEMA cements were found to decrease significantly after storage in Ringer's solution, again with the largest changes to the PEMA cement reinforced with silanated HA. This effect was attributed to the reduction in efficiency of the silane coupling agent in the presence of water. The fatigue resistance of the PMMA cement was not reduced after immersion in a saline environment.

Journal Article↗
PubMed2004

The tube cement of Phragmatopoma californica: a solid foam.

Phragmatopoma californica is a marine polychaete that builds protective tubes by joining bits of shell and sand grains with a secreted proteinaceous cement. The cement forms a solid foam (closed cells) via covalent crosslinking, as revealed by electron and laser scanning confocal microscopy. The cement contains extractable calcium and magnesium, and non-extractable phosphorus. Amino acid analysis demonstrated that the phosphorus is in the form of phosphoserine and that >90% of serine in the cement (i.e. 28 mol% of residues) is phosphorylated. In addition to previously identified basic proteins, the cement contains a highly acidic polyphosphoserine protein as a major component. We propose a model for the structure and bonding mechanism of the cement that has the following major features: (1) within the secretory pathway of cement gland cells, the electrostatic association of the oppositely charged proteins and divalent cations (Ca2+ and Mg2+) condense the cement proteins into dehydrated secretory granules; (2) the condensation of the cement leads to the separation of the solution into two aqueous phases (complex coacervation) that creates the closed cell foam structure of the cement; (3) rehydration of the condensed cement granules after deposition onto tube particles contributes to the displacement of water from the mineral substrate to facilitate underwater adhesion; and (4) after secretion, covalent cross-linking through oxidative coupling of DOPA gradually solidifies the continuous phase of the cement to set the porous structure.

Amino Acids↗
PubMed2006

Setting properties of four acrylic and two calcium-phosphate cements used in vertebroplasty.

STUDY DESIGN: Experimental study conducted in the laboratory with six different bone cements. OBJECTIVES: To isolate the thermal properties of conventional and emerging bone cements used in vertebroplasty and to characterize their setting behavior. SUMMARY OF BACKGROUND DATA: The heat released during setting has been linked to the desirable effects of pain relief and tumor destruction and to the undesirable effect of thermal necrosis of surrounding tissue. However, there are currently no studies that disconnect the exothermic reaction of the cements from the media in which they occur. Before the combined thermal effect is examined, it is important to understand the setting properties of cements alone. METHODS: Thirty independent experiments were conducted with four PMMA cements (Cranioplastic, Vertebroplastic, Palacos LV-40, Antibiotic Simplex) and two calcium-phosphate cements (chronOS Inject and Biopex) in accordance with ASTM standard F 451-99a. A thermocouple was placed in the center of the cement mass, and the temperature-versus-time measurements were recorded. RESULTS: The calcium-phosphate cements took over half an hour to reach their maximum temperature, which was only 3-4 degrees C higher than the ambient temperature. The temperature increase for the acrylic cements was between 16 and 23 degrees C, and it took about 15 minutes to reach the maximum temperature. The variation within the groups was also important. CONCLUSION: The exothermic reaction of calcium-phosphate cements appears to be insignificant. Although the acrylic cements release considerably greater heat in a much shorter time period, it does not appear that their temperature is sufficiently high to cause extensive thermal injury. However, variations within each group must be considered along with the intended use when deciding on the cement to be used.

Calcium Phosphates↗
PubMed2003

PMMA-based bioactive cement: effect of CaF2 on osteoconductivity and histological change with time.

A new bioactive bone cement (designated GBC), which is a polymethyl methacrylate- (PMMA-) based composite consisting of bioactive glass beads as an inorganic filler and high-molecular-weight PMMA (hPMMA) as an organic matrix, has been developed. The bioactive glass beads consist of MgO-CaO-SiO(2)-P(2)O(5)-CaF(2) glass. The purpose of the present study was to evaluate the effect of CaF(2) on osteoconductivity and to evaluate the degree of cement degradation with time. Three different types of cement were prepared. GBC(F +), which has been previously described, consisted of CaF(2)-containing bioactive glass beads and hPMMA. GBC(F -) consisted of CaF(2)-free bioactive glass beads and hPMMA. The third cement was hPMMA itself (as a reference material). These three types of cement were packed into the intramedullary canals of rat tibiae to evaluate osteoconductivity, as determined by an affinity index calculated as the length of bone in direct contact with the cement surface expressed as a percentage of the total length of the cement surface. Rats were killed at 4, 8, 25, and 52 weeks after implantation, and the affinity index was calculated for each type of cement at each time point. Histologically, new bone had formed along the surface of both GBC(F +) and GBC(F -) within 4 weeks, whereas hPMMA had little contact with bone, and an intervening soft tissue layer between bone and cement was detected. No significant difference in affinity index was found between GBC(F +) and GBC(F -) at any of the time points studied, although GBC(F -) showed higher affinity indices than GBC(F +) at 8, 25, and 52 weeks. The affinity indices for GBC(F +) and GBC(F -) were significantly higher than those for hPMMA at all time points. With GBC(F +) and GBC(F -), significant increases in the affinity indices were found as the implantation period increased, and the affinity index values at 52 weeks reached more than 70%. In hPMMA, no significant increase in affinity index was observed up to 52 weeks, and the value at 52 weeks was less than 30%. Although no significant difference in affinity index was found between GBC(F +) and GBC(F -), GBC(F -) is conclusively better than GBC(F +) because diseases such as chronic fluorosis might be caused by CaF(2)-containing glass beads. Regarding the cement degradation of both GBC(F +) and GBC(F -), the degree of the degradation at 25 weeks was the same as that at 52 weeks. Therefore, the cement degradation does not appear to proceed rapidly. Further studies are needed to better understand the degradation process.

Animals↗
PubMed2003

[Stability and occlusion of six different femoral cement restrictors].

Cement restrictors play an integral part in modern cementing technique in total hip arthroplasty. By sealing the femoral cavity, distal cement leakage is prevented and the intramedullary pressure is increased. Thus both the ability of the cement to interdigitate with bone and secondarily the shear strength of the cement bone interface are enhanced. For this purpose various plug models are available, which differ in design and material. Six different cement restrictors were investigated in a biomechanical model with regard to intramedullary implantation pressure, insertion force and in particular stability and sealing ability. We performed a pressure and stability measurement in artificial saw bones during the insertion and standardised cement application and pressurisation. The REX Cement Stop, which is the only intramedullary expandable cement restrictor, yielded the best results in all of the parameters investigated. The flexible gelatin plugs (Biostop G, IMSET, Plugin Tech) also reached a sufficient canal occlusion and stability, but with slightly higher insertion pressures and forces. However, the more rigid polyethylene restrictors (BUCK, Universal Cement Restrictor) showed a reduced stability and poor sealing ability. The latter devices cannot be recommended for use with modern cementing techniques.

Arthroplasty, Replacement, Hip↗
PubMed2004

Enhancement of initial stability of press-fit femoral stems using injectable calcium phosphate cement: an in vitro study in dog bones.

In this in vitro study we evaluated the initial stability of cementless femoral stems using an injectable calcium phosphate (Ca-P) cement. The cement was not used to form a cement mantle as is routinely done in PMMA cemented prostheses but functioned as an additive to fill the small gaps that exist between a press-fit placed titanium plasma sprayed implant and the bone bed. Six pair of Beagle femora were used in this study. In a random fashion, one femur of each pair was used for placement of a prosthesis without Ca-P cement, the contralateral was used for press-fit placement after injection of the calcium phosphate cement into the intramedullary canal. The reconstructions were placed in a MTS testing machine, tilted 15 degrees in varsus and 15 degrees of endorotation to obtain a physiological load on the femoral head. The load was applied stepwise from zero to a maximum of 100, 250 and 400 N, respectively. At each loading step the load was applied dynamically at a frequency of 1 Hz for 30 min. Between the loading steps, the load was removed for 10 min to allow elastic recovery. The stability of the stems was determined at each loading step with roentgen-stereophotogrammetric analysis. Results showed that with the prostheses without Ca-P cement the most important displacements were movement into varus (max. 818 microm under 400 N) and subsidence (max. 587 microm under 400 N). The displacements showed large variation. After unloading some elastic recovery occurred. In the specimens with Ca-P cement, displacements were negligible. As determined by an F-test the variations found were significantly smaller for the press-fit+Ca-P cement relative to the press-fit prosthesis at all loading steps (p<0.05). A paired t-test revealed significant differences in the mentioned displacements between the press-fit- and press-fit+Ca-P cement prosthesis at a loading with 400 N (P<0.05). On the basis of these results we conclude that the use of Ca-P cement increases the initial stability of press-fit inserted plasma-sprayed femoral prostheses and corrects for the high variability in displacements found with press-fit insertion of these femoral hip prostheses.

Adhesiveness↗
PubMed1998

Tensile bond strengths of dual-cured cements between a glass-ceramic and enamel.

STATEMENT OF THE PROBLEM: Dual-cured cements have been used with castable ceramic restorations, but the tensile bond strengths of these materials have not been thoroughly researched. PURPOSE OF THE STUDY: This study compared the tensile bond strengths between Dicor castable ceramics and enamel of four dual-cure cements: Twinlook, Optec Dual-Cure Luting Cement, Clearfil CR Inlay, and Dual Cement. MATERIAL AND METHODS: Truncated cones made of Dicor castable ceramics were cemented to enamel of freshly extracted anterior teeth with these four cements. Before testing, all specimens were immersed in water at 37 degrees C for 24 hours, and thermocycled 1000 times in 5 degrees C and 55 degrees C water, with a dwell time of 30 seconds each. Tensile force was used to separate each specimen with the Instron universal testing machine. RESULTS: Clearfil CR Inlay cement exhibited the highest mean tensile bond strength (18.4 MPa), followed by Dual (18.3 MPa), Twinlook (15.2 MPa), and Optec Dual-Cure luting (14.9 MPa) cements. One-way analysis of variance did not reveal any significant differences (p = 0.05) among groups. A majority of the fracture was adhesive at the ceramic and cement interface. CONCLUSION: All four dual-cured cements formed strong bonds between enamel and Dicor cement, ranging from 14.90 MPa to 18.35 MPa, and there was no statistically significant difference.

Analysis of Variance↗
PubMed2003

Evaluation of a new 2-paste glass ionomer cement.

A new 2-paste resin-reinforced glass ionomer cement, Fuji Ortho Band Paste Pak (GC Corporation, Tokyo, Japan), for the placement of orthodontic bands, has been developed for easier handling. The aim of this study was to compare the fluoride release and uptake characteristics of this cement with that of 3 others commonly used to cement orthodontic bands: a conventional resin-reinforced glass ionomer cement, a polyacid-modified composite resin, and a conventional glass ionomer cement. Fluoride release was measured during a 28-day period. After the measurement on day 28, experimental samples were exposed to 1000 ppm sodium fluoride solution for 5 minutes, and fluoride release was then measured for 7 days. Initially, the new 2-paste resin-reinforced glass ionomer cement released the greatest amount of fluoride; the polyacid-modified composite resin released the least initially, and it continued to show the lowest values throughout the study. The fluoride uptake and release values of the new 2-paste resin-reinforced glass ionomer cement were statistically significantly higher than those of the conventional resin-reinforced glass ionomer cement or the conventional glass ionomer cement. The new 2-paste resin-reinforced glass ionomer cement might be a good alternative to conventional products for cementing orthodontic bands.

Absorption↗
PubMed2001

Effect of three adhesive primers for a noble metal on the shear bond strengths of three resin cements.

The purpose of this study was to evaluate the durability and shear bond strengths of the different combinations of three adhesive primers and three resin cements to a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy. The adhesive primers Alloy Primer (AP), Metal PrimerII (MPII) and Metaltite (MT), and the resin cements BistiteII (BRII), Panavia Fluoro Cement (PFC) and Super-Bond C&B (SB) were used. Two sizes of casting alloy disks were either non-primed or primed and cemented with each of the three resin cements. The specimens were stored in a 37 degrees C water bath for 24 h and then immersed alternately in 4 and 60 degrees C water baths for 1 min each for up to 100,000 thermal cycles. Shear mode testing at a crosshead speed of 0.5 mm/min was then performed. The application of MPII or MT was effective for improving the shear bond strength between each of the three resin cements and the Ag-Pd-Cu-Au alloy compared with non-primed specimens. However, when primed with MPII or MT and cemented with SB, the bond strength at 100,000 thermal cycles was significantly lower than that at thermal cycle 0. When primed with AP, the specimens cemented with BRII or PFC showed lower bond strength than non-primed specimens and failed at the metal-resin cement interface at 100,000 thermal cycles. On the other hand, AP was effective in enhancing the shear bond strength of SB to the Ag-Pd-Cu-Au alloy. The five combined uses of an adhesive metal primer and resin cement (combinations of MPII or MT and BRII or PFC and AP and SB) are applicable to the cementation of prosthodontic restorations without complicated surface modification of the noble alloy.

Adhesives↗
PubMedDate not supplied

[Cemented total knee arthroplasties].

INTRODUCTION: The aseptic loosening of cemented total knee arthroplasties is still an unsolved problem. In this regard, the hydrolysis resistance in the metal-to-bone cement interface is of major importance. MATERIAL AND METHODS: Cemented pre-treated tibia components coated by means of a silica/silane interlayer system of the model "Columbus PS" were dynamically loaded with the help of a knee-simulator similar to DIN ISO 14243. After loading, the components were microscopically analysed concerning debonding in the metal-to-bone cement interface as well as with regard to cement mantle defects. These data were matched with uncoated "Columbus PS" components. Unloaded coated and uncoated tibia components acted as a control. RESULTS: In comparison with uncoated tibia components, the pre-treated and coated ones yielded a highly significant reduction of cement defects (p < 0.01) as well as a significant reduction of debonding in the metal-to-bone cement interface (p < 0.05). CONCLUSION: By means of the silica/silane interlayer system for cemented tibia components, a hydrolytic debonding in the metal-to-bone cement interface with subsequent mechanical loosening and consecutive early cement mantle failure can be significantly reduced. This could lead to an increased long-term stability of the metal-to-bone cement compound with decreased aseptic loosening in clinical use.

Adhesiveness↗
PubMedDate not supplied

Calcium phosphate cement: review of mechanical and biological properties.

PURPOSE: Calcium phosphate cement is a bioactive and biodegradable grafting material in the form of powder and liquid, which when mixed, sets as primarily hydroxyapatite, sometimes mixed with unreacted particles and other phases. This material has been extensively investigated due to its excellent biological properties, potential resorbability, molding capabilities, and easy manipulation. Because the material can potentially be replaced with bone after a period of time, it could retain the short-term biological advantages of hydroxyapatite without the long-term disadvantages. Although little is known about this material in the dental community, in vivo and in vitro studies show calcium phosphate cement as a promising material for grafting applications. In the following article, the authors review the biological and mechanical properties of calcium phosphate cement, as well as its potential use in clinical applications. MATERIALS AND METHODS: A Medline search was performed (timeline: 1980 to 2003) using the following keywords: calcium phosphate cement, hydroxyapatite cement, HA cement, and hydroxyapatite. The search was limited to the English language. The patent literature as well as a limited number of master's theses and books were reviewed after using the electronic database search service from a dental school library. RESULTS: Calcium phosphate cement appears to have excellent biological properties. At only 2 weeks, spicules of living bone with normal bone marrow and osteocytes can be seen. Excellent moldability is a desired clinical characteristic; however, further research is necessary in order to improve the mechanical properties of the cement. The resorption/replacement by bone capability of the cement remains controversial. Further research is needed to clarify this issue. Due to poor mechanical properties, clinical applications are currently limited to craniofacial applications. Further research is necessary to take advantage of the excellent biological properties of this cement under clinical applications. CONCLUSION: Further research is necessary to understand and improve the behavior of this type of cement under clinical situations.

Absorbable Implants↗
PubMed2003

Finite element thermal analysis of bone cement for joint replacements.

A finite element technique was developed to investigate the thermal behavior of bone cement in joint replacement procedures. Thermal tests were designed and performed to provide the parameters in a kinetic model of bone cement exothermic polymerization. The kinetic model was then coupled with an energy balance equation using a finite element formulation to predict the temperature history and polymerization development in the bone-cement-prosthesis system. Based on the temperature history, the possibility of the thermal bone necrosis was then evaluated. As a demonstration, the effect of cement mantle thickness on the thermal behavior of the system was investigated. The temperature profiles in the bone-cement-prosthesis system have shown that the thicker the cement, the higher the peak temperature in the bone. In the 7 mm thick cement case, a peak temperature of over 55 degrees C was predicted. These high temperatures occurred in a small region near the bone/cement interface. No damage was predicted in the 3 mm and 5 mm cement mantle thickness cases. Although thermal damage was predicted in the bone for the 7 mm mantle thickness case, the amount of thermal necrosis predicted was minimal. If more cement is used in the surgical procedure, more heat will be generated and the potential for thermal bone damage may rise. The systems should be carefully selected to reduce thermal tissue damage when more cement is used. The methodology developed in this paper provides a numerical tool for the quantitative simulation of the thermal behavior of bone-cement-prosthesis designs.

Animals↗
PubMed2003

The efficacy of luting all-ceramic crowns with resin-modified glass ionomer cement.

BACKGROUND: The authors conducted studies to determine if hygroscopic expansion of resin-modified glass ionomer, or RMGI, cement would cause fracture of the sintered aluminum oxide copings of all-ceramic crowns. MATERIALS AND METHODS: The authors scanned standardized dies using computer-aided design/computer-aided manufacture technology. Aluminum oxide copings were fabricated, inspected and luted onto titanium dies. The copings were seated with 11 pounds of force for 10 minutes. The copings were placed in a container with 100 percent humidity and stored at room temperature. At appropriate intervals, the authors inspected the copings with surgical loupes and under microscopic magnification. The authors also inspected the copings before conducting load testing. RESULTS: After six and 12 weeks, the authors found no signs of fracture in any of the 30 copings cemented with one of two RMGI cements. Seventeen additional samples were inspected four years after cementation, and no fractures were evident. In a follow-up study, the authors cemented 18 copings with RMGI cement one week before testing, 10 weeks before testing or 60 weeks before testing. Using a universal testing machine, they loaded the samples to fracture at 0.5 millimeter/minute. Statistical analysis indicated a significant difference in the mean load-to-fracture values between the samples tested one week after cementation and those tested 60 weeks after cementation. CONCLUSIONS: The results showed no fracture of the all-ceramic copings as a result of expansion of the cement alone. The mean load-to-fracture values were significantly greater for the group tested 60 weeks after cementation. CLINICAL IMPLICATIONS: The all-ceramic crowns examined in this study demonstrated excellent esthetics, incorporated a strong coping system and allowed ease of cement choice.

Cementation↗
PubMed2003

Cemented revision of failed uncemented femoral components of total hip arthroplasty.

BACKGROUND: The long-term results of revision of failed primary cemented femoral components with use of cement have been reported, but there is little information about the results of revision of failed uncemented femoral components with use of cement. The purpose of the present study was to examine the minimum five-year results for patients in whom a failed uncemented primary femoral component was revised with use of modern cementing techniques. METHODS: Forty-eight consecutive hips (forty-seven patients) in which a failed primary uncemented femoral component was revised with use of cement at one institution from 1985 to 1992 were followed prospectively and reviewed retrospectively. The mean age of the patients at the time of revision was sixty-seven years. Only seven revisions were performed with a long-stem femoral component. The postoperative cement mantle was classified, according to the system of Mulroy and Harris, as grade A in four hips, grade B in twenty-five, grade C1 in seven, grade C2 in twelve, and grade D in none. RESULTS: Eleven femoral components were removed or revised because of aseptic loosening (ten) or deep infection (one). An additional four unrevised femoral components had evidence of probable or definite loosening at the time of the final radiographic follow-up. Thus, fourteen (29%) of the forty-eight femoral implants demonstrated aseptic loosening during the study period. Five of the twenty-nine hips in which the postoperative cement mantle was classified as grade A or B had mechanical failure at the time of the final follow-up, compared with nine of the nineteen hips in which the postoperative cement mantle was classified as grade C1 or C2 (p < 0.05). Among the hips with surviving prostheses, 79% had had moderate or severe pain preoperatively whereas 25% had moderate or severe pain at the time of the final follow-up. The six-year rate of survival of the femoral component was 72% with revision for aseptic loosening as the end point and 67% with mechanical failure (revision for aseptic loosening or radiographic loosening) as the end point. CONCLUSIONS: While revision of a failed uncemented femoral implant with use of cement provided pain relief and improved function for most patients, the rate of loosening at the time of intermediate-term follow-up was higher than that commonly reported after revision of failed cemented implants with use of cement and also was higher than that commonly reported after revision with use of uncemented extensively porous-coated implants. Bone removal at the time of the initial implantation of the stem and bone loss due to subsequent failure of the uncemented implant often left little intramedullary cancellous bone, which may explain the high rate of loosening observed in the first decade after revision in this series.

Age Factors↗
PubMedDate not supplied

The effect of eugenol-containing and eugenol-free temporary cements on microleakage in resin bonded restorations.

Eugenol is known to have a detrimental effect on both composite resin and dentin bonding agents. The purpose of this in vitro investigation was to compare the microleakage among groups of resin-luted inlays when the cavity preparations were pretreated with a eugenol-containing temporary cement, a eugenol-free temporary cement, or no temporary cement. Class 5 inlay preparations (20 per group) were completed in extracted human molars. Following the fabrication of composite resin inlays, the preparations were filled with either a eugenol-based temporary cement, a eugenol-free temporary cement, or no cement. After removal of the cement from the cavity preparations and application of a dentin bonding agent, the composite inlays were luted with a resin cement, thermocycled, stained, sectioned, and evaluated for microleakage under a stereomicroscope. None of the groups exhibited significant leakage at the enamel margins. Both of the groups treated with temporary cement leaked at the nonenamel margins significantly more than the control (no cement) group. No significant difference in leakage was demonstrated between the groups treated with the eugenol-containing and the eugenol-free temporary cements.

Analysis of Variance↗
PubMedDate not supplied

The shear bond strength between luting cements and zirconia ceramics after two pre-treatments.

This study evaluated the shear-bond strength of 11 luting cements from different material classes to manufactured pre-treated zirconia ceramics (Lava: 97% ZrO2, stabilized with 3% Y2O3). In addition, the influence of the curing method on shear-bond strength was investigated. The cements examined were one zinc-phosphate cement (Fleck's zinc cement), two standard glass-ionomer cements (Fuji I, Ketac-Cem), three resin-modified glass-ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), four standard resin cements (RelyX ARC, Panavia F, Variolink II, Compolute) and one self-adhesive universal resin cement (RelyX Unicem). The ceramic surface was sand-blasted with 100-microm alumina or tribochemically coated with silica. After bonding procedure, one group was tested after 30 minutes (Time I), the other group was stored in distilled water at 37 degrees C for 14 days and subsequently thermocycled 1000 times (Time II). Statistical analysis was performed by multifactorial ANOVA models with interactions. For multiple pairwise comparisons, the Tukey method was used. After sandblasting, the highest shear-bond strength was obtained for the self-adhesive universal resin cement at 9.7 MPa (Time I) and 12.7 MPa (Time II), respectively. When using the Rocatec system, the highest values were found for one of the resin cements at 15.0 MPa (Time I) and for the self-adhesive universal resin cement at 19.9 MPa (Time II).

Analysis of Variance↗
PubMed1982

A cement fixation system for total hip arthroplasty.

To combat the most common and most serious cause of mechanical failure of total hip arthroplastics, namely loosening, a method of improving the insertion of methacrylate is presented, called the cement fixation system. Using the cement gun with the keying hole seal, the methacrylate is pressure injected into the keying holes in the acetabulum. The acetabular cement compactor pressurizes the rest of the cement used in the acetabulum. The medullary canal of the femur is occluded by a bolus of methacrylate delivered to the desired depth by the medullary plug syringe. Thus, the cement is delivered from the plug proximally via the cement gun and femoral cement syringe. Finger packing is not used. The entire femoral cement mass is then pressurized using the femoral cement compactor. This cement fixation system produces higher extrusion pressure, better penetration of the cement, better fixation to the bone and reduces voids, defects, and discontinuities in the methacrylate mantle.

Bone Cements↗