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PubMed1979

[The in vitro biological evaluation of dental cements using elution and binding by bovine serum albumin (author's transl)].

In order to evaluate in vitro biological properties of dental cements sixteen different cements including zinc oxide eugenol (ZOE), EBA, resin, polycarboxylate, glass ionomer cement and calcium hydroxide base material were tested regarding elution and binding by bovine serum albumin (BSA). The persistency of elution over long time after subsequent transfer to fresh water was calculated at 210 nm absorbance with ultra violet spectrometer. Also the eluates obtained were analyzed by high performance liquid chromatograpy. The continuous leaching of eugenol from ZOE cement was observed. Binding of eluates from cement to BSA was evaluated spectrophotometrically by utilizing the competition with 2-(4' hydroxyphenylazo) benzoic acid (HABA). EBA cement showed the highest binding ability by BSA because of the leaching o-ethoxybenzoic acid from this cement. The relevance of protein and pulp toxicity is discussed.

Animals↗
PubMed1997

Bone bonding ability of bioactive bone cements.

The bone bonding ability of three types of bioactive bone cement A, B, and C consisting of glass or glass ceramic powder and bisphenol-alpha-glycidyl methacrylate resin was evaluated. Type A contained MgO-CaO-SiO2-P2O5-CaF2 glass powder; Type B, MgO-CaO-SiO2-P2O5-CaF2 glass ceramic powder; and Type C, MgO free CaO-SiO2-P2O5-CaF2 glass powder. Rectangular plates (2 x 10 x 15 mm) of Types A, B, C, and polymethylmethacrylate cements were implanted into the tibial metaphyses of male rabbits and the failure load measured by mechanical failure testing (detaching test) 10 and 25 weeks after implantation. The failure loads of Types A, B, C, and polymethylmethacrylate cements were respectively, 29.52, 41.48, 28.22, and 0.29 N at 10 weeks and 33.42, 41.27, 33.64, and 0.20 N at 25 weeks. Examination of the bone cement interface revealed that all the bioactive bone cements achieved direct bone contact with the bone. These results showed that all three types of bioactive bone cement have the ability to bond to bone, and the cement containing glass ceramic powder revealed higher bonding strength than did those containing glass powder.

Animals↗
PubMed1998

A comparison of bond strengths of complete crowns using two types of cements and three cleaning agents.

This study evaluated the influence of three cleaning agents on the bond strength of complete crowns cemented with zinc phosphate and polycarboxylate cements. For the polycarboxylate cement group, three cleaning agents were used: Tergentol; Tergentol + polyacrylic acid; Tergentol + citric acid. Zinc phosphate cement was used as a control group with Tergentol. There were no statistically significant differences of mean retentive force for either cement regardless of the test conditions. The marginal fit after cementation was also evaluated and the results of zinc polycarboxylate were lower than zinc phosphate cement and were statistically significant.

Acrylic Resins↗
PubMed1980

The flow properties of dental cements.

The flow properties of several major types of dental cements were investigated using slow compressive strength and creep techniques. Considerable differences were found in their behavior. Whereas the phosphate-bonded and glass-ionomer cements exhibited brittle fracture, the other cements tended to distort to a greater or lesser extent under load. All cements showed some creep under load but the extent of this varied considerably; the creep of phosphate-bonded cements being very small and that of the eugenol and related cements considerable.

Dental Cements↗
PubMed1996

Effect of two dentinal desensitizing agents on retention of complete cast coping using four cements.

The cementation of artificial crowns is commonly accompanied by sensitivity, so the clinical application of desensitizing agents has become prevalent. This study investigated the effects of Imperva bonding agent and All-Bond desensitizing agent on the retention of artificial crowns. The cements selected for this study were: zinc phosphate, polycarboxylate, glass ionomer, and resin luting agents. Extracted, intact, human molars were mounted in autopolymerizing acrylic resin and prepared for complete cast copings. Thirty-two teeth were treated with All-Bond desensitizing agent, 32 teeth with Imperva bonding agent, and 32 remained untreated. Castings were cemented and tested on an Instron testing machine. The results demonstrated a significant reduction in retention when All-Bond desensitizing agent was used with polycarboxylate cement and some reduction with zinc phosphate cement. Imperva bonding agent demonstrated less retention with glass ionomer cement.

Analysis of Variance↗
PubMed2001

Effect of ultrasonic vibration and various sealer and cement combinations on titanium post removal.

The purpose of this study was to determine the effect of ultrasonic vibration on the force required to remove prefabricated posts. Ninety-six extracted human canines were divided into eight groups, which were prepared and obturated with gutta-percha and either a eugenol-containing (Roth's 801 Elite) or eugenol-free (AH26) sealer. Titanium #6 Parapost XH posts were cemented with either zinc phosphate or Panavia 21 resin cement. One half of the sample was subjected to ultrasonic vibration for 16 min at the post-dentin interface, whereas the other half received no vibration (controls). Each combination of sealer, cement, and vibration status was subjected to tensile load to failure using an Instron testing machine. Posts cemented in teeth obturated with gutta-percha and AH26 sealer demonstrated significantly greater resistance to dislodgement, compared with teeth obturated with gutta-percha and Roth's 801 Elite sealer. There was no statistical difference in retention of posts cemented with either zinc phosphate or Panavia 21, regardless of the sealer used. Additionally ultrasonic vibration increased post retention for both cements.

Analysis of Variance↗
PubMed1987

Morphology of the osteonal cement line in human bone.

While current consensus suggests the absence of collagen in osteonal cement lines, the extent of cement line mineralization and the nature of the ground substance within the cement line are unclear. Samples of human radius were examined by using scanning electron microscopy, electron microprobe, and histochemical techniques. X-ray intensities were used to compare the amount of calcium, phosphorus, and sulfur in cement lines with amounts in surrounding lamellar bone. The results indicate that cement lines contain significantly less calcium and phosphorus, but significantly more sulfur, than surrounding bone matrix. The Ca/P ratio of cement lines was significantly greater than that of lamellar bone, suggesting that the mineral in cement lines may not be in the form of mature hydroxyapatite. No selective staining of the cement lines could be demonstrated by using periodic acid-Schiff, Sudan black B, or alcian blue critical electrolyte concentration techniques.

Adult↗
PubMed2003

Biocompatibility and other properties of acrylic bone cements prepared with antiseptic activators.

Acrylic bone cements prepared with activators of reduced toxicity have been formulated with the aim of improving the biocompatibility of the final material. The activators used were N,N-dimethylaminobenzyl alcohol (DMOH) and 4,4'-dimethylamino benzydrol (BZN). The toxicity, cytotoxicity, and antiseptic action of these activators were first studied. DMOH and BZN presented LD50 values 3-4 times higher than DMT, were less cytotoxic against polymorphonuclear leucocytes, and possessed an antimicrobial character, with a high activity against the most representative microorganisms involved in postoperative infections. The properties of the acrylic bone cements formulated with DMOH and BZN were evaluated to determine the influence of these activators on the curing process and the physicochemical characteristics of the cements. A decrease of the peak temperature was observed for the curing with DMOH or BZN with respect to that of one commercially available formulation (CMW 3). However, residual monomer content and mechanical properties in tension and compression were comparable to those of CMW 3. The biocompatibility of acrylic bone cements containing DMOH or BZN was studied and compared with CMW 3. To that end, intramuscular and intraosseous implantation procedures were carried out and the results were obtained from the histological analysis of the surrounding tissues at different periods of time. Implantation of rods of cement into the dorsal muscle of rats showed the presence of a membrane of connective tissue, which increased in collagen fibers with time of implantation, for all formulations. The intraosseous implantation of the cements in the dough state in the femur of rabbits, revealed a higher and early osseous neoformation, with the presence of osteoid material surrounding the rest of the cured material, for the cement prepared with the activator BZN in comparison with that obtained following the implantation of the cement cured with DMOH or DMT (CMW 3).

Alcohols↗
PubMed2005

Osteolytic potential of triphenyl bismuth as an alternative contrast medium in acrylic bone cement.

Radiopaque cement containing barium sulfate causes significantly more bone resorption in vivo and in vitro than radiolucent cement. The aim of this study was to investigate the osteolytic potential of an alternative radiopaque agent, triphenyl bismuth (TPB). Bone cement particles containing various concentration of TPB (15 and 25 wt %) prepared by two methods, blending and dissolution, were added to monocytes in a bone resorption assay and the extent of lacunar resorption on dentine slices was determined. The results clearly show that cement particles containing TPB cause less bone resorption than cement particles containing barium sulfate. In addition, our results suggest that TPB prepared by dissolution in bone cement induces less osteolytic response than TPB-cement prepared by blending. The osteolysis in response to bone cement wear particles may therefore be reduced with TPB prepared using the blending technique.

Animals↗
PubMed2007

Influence of changes in the composition of an acrylic bone cement on its polymerization kinetics.

It has been suggested in the literature that a lower polymerization rate of an acrylic bone cement is favorable for the in vivo longevity of a cemented arthroplasty. The present work was a study of the influence of three changes in the composition of an acrylic bone cement (when taken separately) on the cement polymerization rate at 37 degrees C (assumed to be the temperature in the bone bed during a cemented arthroplasty) [k']. The changes were the amount of copolymer as a proportion of the total powder weight (in cements in which there is a copolymer in the powder), the amount of DMPT as a proportion of the total volume of the liquid monomer, and the accelerator. k' was calculated using values of the activation energy and the frequency factor (assuming the polymerization reaction is Arrhenius in nature) that were computed from measurements made using the nonisothermal mode of differential scanning calorimetry. Statistical analysis (one-way ANOVA, with Bonferroni correction, and factorial ANOVA) of the k' values showed that the change in accelerator had a significant influence on k'. The importance of this finding, together with results from two relevant literature reports, is discussed within the context of the use of modified bone cements in cemented arthroplasties.

Arthroplasty, Replacement↗
PubMed2001

Effect of filler size on wear resistance of resin cement.

The purpose of this study was to evaluate the effect of filler size on the wear of resin cements. Materials tested included four experimental dual-cure resin cements (Kuraray) consisting of different-sized filler particles. A rectangular box cavity was prepared on the flattened occlusal surface of extracted human molars. Ceramic inlays for the cavities were fabricated using the Cerec 2 system. The Cerec inlays were cemented with the respective cements and adhesive systems according to the manufacturer's directions. The restored surface was finished by wet-grinding with an 800-grit silicon carbide paper. Six specimens were prepared for each resin cement. Half of the specimens were subjected to a three-body wear test for 200,000 cycles, and the others were subjected to a toothbrush abrasion test for 30,000 cycles. The worn surface of each restoration was scanned by a profilometer (Surfcom 475 A) at eight different points for each restoration. The wear value was determined by measuring the vertical gap depth on the profilometric tracings. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Scheffe's test. The results showed that, with increase of filler size, the wear value decreased in the toothbrush test and increased in the three-body wear test. The cement with 0.04-microm filler exhibited the lowest wear value among the materials in the three-body wear test, and the same wear value as the cement with 0.97-microm filler in the toothbrush test. Based upon the results of this study, it is concluded that the wear of resin cements was affected by the filler size as well as the mode of wear test.

Journal Article↗
PubMed2006

Optimisation of the composition of an acrylic bone cement: application to relative amounts of the initiator and the activator/co-initiator in Surgical Simplex P.

In cemented arthroplasties, the two-part self-curing acrylic bone cement is currently the only material used for anchoring the total joint replacement to the contiguous bone. In virtually all commercially available formulations of this cement, the agents used for the initiation and activation/co-initiation of the radical polymerisation reaction are benzoyl peroxide (BPO) and N, N dimethyl-para-toluidine (DMPT), respectively. There are no reports in the open literature on the rationale for the amounts of these and other constituents in the formulations of the cement. Given the concerns that have been raised in the literature regarding the effect of residual DMPT on the body, it is important to keep the starting amounts of BPO and DMPT as high and as low, respectively, as possible. In the present work, the focus is on the relative amounts of these two agents in the case of one widely used commercial formulation, Surgical Simplex(R) P. Thirty variants of this cement were formulated, covering three concentrations of the co-polymer/BPO (75%, 80%, and 85% of the mass of the powder) and DMPT amounts (ranging from 0.8 %v/v to 2.4% v/v.) The setting time (t(set)), the peak temperature reached during the cement polymerisation process (T(max)), and the ultimate compressive strength (UCS) of each of the formulations were determined in accordance with procedures specified in ISO 5833. A critical examination of all the results indicated that the optimum ratio of the concentration of the initiator (BPO embedded in the PMMA-sytrene co-polymer) to that of the activator/co-initiator (DMPT) in Surgical Simplex(R) P is 57.14 (80%w/w co-polymer + BPO per 1.4%v/v DMPT). The mean values of t(set), T(max), and UCS of this optimum formulation were determined to be 12.30 min, 68 degrees C, and 101 MPa, respectively, all of which are within the limits specified in ISO 5833. The commercially available formulation of this cement contains 2.5%v/v DMPT, while the optimum formulation, as found in the present work, has 44% less DMPT, which may translate to a smaller amount of residual DMPT that is available for elution into the periprosthetic tissue in a cemented arthroplasty, over the in vivo life of the joint replacement.

Adhesiveness↗
PubMed1985

Radon emanation from concrete and the influence of using flyash in cement.

In the Netherlands both Portland cement and blast furnace cement (slags from blast furnaces with about 30% Portland cement) are used for concrete. Radon exhalation measurements were carried out on concrete blocks made with these two types of cement and blocks with 15, 25 and 35% of the cement substituted by three different types of flyash. The results show that substituting part of the cement by flyash has no drastic effect on the exhalation rate. For concrete with Portland cement the exhalation rate decreases using flyash with an average radium content. With blast furnace cement a slight increase may be expected. The exhalation of concrete is greater than the sum of the exhalation values of the constituting components. The water in the pores of the concrete plays an essential role in the emanation process.

Calcium Hydroxide↗
PubMed2004

Fixation strength of an all-metal acetabular component cemented into an acetabular shell: a biomechanical analysis.

When an acetabular shell is well fixed but the locking mechanism is compromised, cementing a new liner into the existing acetabular component can provide a simple revision solution. The pull-out and torsional fixation strength of cobalt chromium (CoCr) alloy acetabular components cemented into 3 sizes of titanium alloy acetabular components was tested under conditions of 0 or 2 mm cement mantle at the dome and 2 mm cement with the cemented component in 20 degrees of version with respect to the shell. The lowest mean tensile load to failure was 1500 N, and occurred with no cement at the dome of the 54 mm shell, whereas the greatest load was with 2 mm cement thickness. Smallest mean torque to failure was 43 Nm. Version angle did not substantially change failure load. Although not cyclically loaded, fixation strength of metal liners cemented into shells was comparable to that of commonly used locking mechanisms, suggesting sufficient strength for clinical application.

Acetabulum↗
PubMed2006

Polished vs rough femoral components in grade A and grade C-2 cement mantles.

The ideal surface for cemented femoral components remains controversial. Six polished stems were compared with 6 rough stems both with good cement mantle and also with poor cement mantles in a stair-climbing model. With good cement mantles, both the polished and the rough stems were loose by 6 million cycles. However, none were loose by radiographic criteria. With the poor cement mantle, both stems became loose earlier and developed more micromotion, the polished stems having significantly higher and earlier motion than the rough. Radiographic evidence of debonding was not visible until the stems had motion of more than 2,000 microm. In the presence of a good cement mantle in this laboratory model there was no significant difference in the development of micromotion under fatigue stair-climbing conditions between a polished or grit-blasted femoral component. However, in the presence of a poor cement mantle, the polished components had earlier and higher micromotion. This study reinforces the importance of centralization and cement technique, particularly if using a polished surface finish.

Arthroplasty, Replacement, Hip↗
PubMed2004

Wet cement remains a poorly recognised cause of full-thickness skin burns.

In 1993 we published a paper stating that wet construction cement is a poorly recognised cause of full-thickness burns [Injury 24 (1993) 615]. Ten years since publication we re-evaluated cement burns to ascertain if there had been any changes in awareness and incidence. All cement related burns assessed at this unit were reviewed over a three and a half year period. Postal questionnaires were sent to all those affected. Cement burns accounted for 2.2% of referrals to the Burns Unit during this studied period as compared to 1% during the original study. Fifty-one percent of patients stated they were unaware of the risk of cement burns and took no precautions. Eighty-six percent of the burns involved the lower limb. Fifty-three percent of burns affected professional users. Fifty percent had full-thickness involvement with 21% requiring operation. Eighty-eight percent of patients did not notice any warnings on the cement bag or delivery docket and 95% felt warnings should be larger and more obvious. This study has shown that cement burns may have resulted from shortcomings in the information and warnings provided to customers by cement manufacturers.

Adolescent↗
PubMed2006

Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement Part 2. Mechanical strength of mortars and environmental impact.

This second of two articles dealing with the utilization of MSWI fly ash in blended cement studies the effects of two variants of the stabilization process on the behavior of the treated fly ash (TFA) introduced into cement-based mortars. From a technological point of view, the modifications of the process are very efficient and eliminate the swelling produced by the introduction of MSWI fly ash in cement-based mortars. TFA has a significant activity in cement-based mortars and can also advantageously replace a part of the cement in cement-based material. From an environmental point of view, the results of traditional leaching tests on monolithic and crushed mortars highlight a poor stabilization of some harmful elements such as antimony and chromium. The use of a cement rich in ground granulated blast furnace slag (GGBFS) with a view to stabilizing the chromium is not efficient. Since neither adequate tests nor quality criteria exist to evaluate the pollutant potential of a waste with a view to reusing it, it is difficult to conclude on the environmental soundness of such a practice. Further experiments are necessary to investigate the environmental impact of TFA introduced in cement-based mortars depending on the reuse scenario.

Carbon↗
PubMed2004

Cement-clay pastes for stabilization/solidification of 2-chloroaniline.

Immobilization of a model liquid organic pollutant, i.e. the 2-chloroaniline (2-CA), into a cement matrix using organoclays as pre-sorbent agents was investigated. Five cement-clay pastes were prepared with different nominal water-to-cement ratios (w/c=0.40, 0.25 and 0.15 wt/wt) and various amounts of waste (waste-to-cement o/c=0.20, 0.60 and 1.00 wt/wt); for comparison, a neat cement paste was also prepared. Dynamic leach tests were performed on solidified monoliths in order to assess the successful immobilization of the 2-CA. In monoliths at constant w/c ratio (0.40) the total amount of pollutant released increases with its initial content, and ranges from 15 to 35% with respect to it. By lowering w/c from 0.40 to 0.15 at constant o/c, the performances improved (<25% released). The microstructure of the hardened cement-clay pastes was characterized by quantitative X-ray diffraction (QXRD) and electronic microscopy (SEM-EDS) techniques; hydration degree was estimated by means of thermogravimetric analysis (TGA) in addition to QXRD. No evidence of any chemical reaction between 2-CA and cement phases was found. Moreover, it was shown that the most important factors affecting the cement hydration process were the total water content, i.e. the one taking also into account the water contained in the wet polluted clay, and the amount of 2-CA not firmly sorbed by the organoclay, and then freely dispersed in the paste.

Aluminum Silicates↗