Biomedical subjects

C M Russell

Publications and source records attributed to C M Russell.

At least 55 records · Page 3Linked to original sources

PubMed1995

Can the Year 2000 objective for reducing overweight in the United States be reached?: a simulation study of the required changes in body weight.

AIM: The purpose of this analysis was to estimate the magnitude of weight change required in the six-year period between 1994 and the Year 2000 if Americans are to reach the Healthy People 2000 goal for reduction of overweight among those ages 20-74 to no more than 20% among all adults and no more than 30% among black women. Prevention of weight gain among the non-overweight is compared with that of weight loss among the overweight as strategies for reaching this goal. DESIGN: Data from the First National Health and Nutrition Examination Survey (NHANES I) and the Nutrition Examination Survey Epidemiologic Follow-up Study (NHEFS) were used to estimate 6-year weight change of persons aged 20 to 72 at the Year 2000. Men, white women, and black women were examined in addition to the overall population. Given a baseline prevalence of 24.7%, overweight in the year 2000 was projected for three simulated interventions: no weight gain among non-overweight persons (prevention-only), weight loss among overweight persons (weight-loss-only), and prevention-plus-weight-loss. In addition, the Year 2000 overweight prevalence was projected under different baseline prevalence scenarios of 26% and 34%. OUTCOME MEASURE: Prevalence of overweight; overweight determined by body mass index (> or = 27.3 kg/m2 for women and > or = 27.8 kg/m2 for men). RESULTS: Prevention-only was successful in reducing the overall prevalence of overweight from 24.7% to 20%. Weight-loss-only required a 5.3 kg weight loss to achieve the overall goal of 20% and 8.4 kg weight loss to achieve the goal within all three race-sex strata. Prevention-plus-weight-loss required only 3.8 kg of weight loss to achieve the goals within the three race-sex strata. Prevention-only was not successful in reducing the overall prevalence of overweight to 20% when the 26% and 34% baseline scenarios were used. Weight-loss-only required 6.3 and 11.2 kg; prevention-plus-weight-loss required 1.2 and 6.6 kg of weight loss using the 26% and 34% baselines, respectively. CONCLUSIONS: Prevention of weight gain among those who are not already overweight could achieve substantial changes in the prevalence of overweight, even in a 6-year time period. However, given the increasing trend in overweight, the Year 2000 goal for the reduction in prevalence of overweight will not be reached.

Adult↗

PubMed1995

A clinical comparison of the efficacy of an electromechanical flossing device or manual flossing in affecting interproximal gingival bleeding and plaque accumulation.

This one-month clinical trial was designed to compare the effect of an electromechanical flossing device and manual flossing on reducing interproximal gingival bleeding and plaque accumulation in a cohort of 60 healthy adults. After baseline evaluation of interproximal gingival bleeding, soft tissue trauma and plaque, patients were randomly assigned to one of the two experimental groups, given flossing instructions, and had their teeth cleaned. At 30 days all three clinical parameters were again evaluated. The results showed a reduction in GI from baseline to follow-up in each group. This effect is significant (p<0.0001) in the analysis of variance. There was no overall difference in the groups (p=0.93). There was no difference in the reduction in GI from baseline to follow-up between the two groups (p=0.91); interaction). As with the GI, there was a significant reduction in PI from baseline to follow-up in each group (p<0.0001). There was no overall difference between the groups (p=0.24). There was no difference in the reduction in PI from baseline to follow-up between the two groups (p=0.59; interaction). No soft tissue trauma was noted at the baseline examination or at the follow-up examination after 30 days.

Adolescent↗

PubMed1994

Factors associated with hepatitis B vaccine response among dentists.

The objective of this study was to evaluate personal and immunization factors associated with serologic evidence of hepatitis B virus (HBV) vaccine response. A study was conducted using data from United States dentists participating from 1987 to 1991 in the Health Screening Program of the American Dental Association's annual session. This study included dentists (n = 507) who (1) received their most recent dose of HBV vaccine within the previous 10 months, (2) completed a core questionnaire, and (3) were tested for HBV markers (HBsAg, anti-HBs, and anti-HBc) and were found not to have evidence of past or present infection. Non-responders were defined as dentists testing negative for all three markers (n = 100). Responders were defined as dentists having serological evidence of anti-HBs alone (n = 407). Logistic regression models were used to assess the relationship of vaccine response to the variables sex, age, number of vaccine doses, site of vaccination, type of vaccine, and history of hepatitis. Vaccine response was most strongly associated with sex, age, and number of doses. Factors unrelated to vaccine response included type of vaccine and history of hepatitis. Adherence to the recommended number of doses and early vaccination are critical to adequate protection against hepatitis B infection of dentists, who are often exposed to blood and other body fluids.

Adult↗

PubMed1994

Laboratory evaluation of the A.R.T. bonding system.

PURPOSE: To determine (1) the in vitro shear bond strengths of the A.R.T. Bond System to dentin at different time intervals, (2) the quantitative microleakage of Class V preparations in dentin restored with the A.R.T. Bond System, and (3) the resin penetration into the dentin tubules by scanning electron microscopy. MATERIALS AND METHODS: The occlusal surfaces of 75 extracted human mandibular and maxillary permanent first and second molars were ground wet on 600-grit SiC to expose the superficial dentin. The A.R.T. Primer and the A.R.T. Adhesive were applied to demarcated bonding sites as recommended by the manufacturer. Brilliant Dentin resin composite was transferred to the opening in a split Teflon mold in the assembly apparatus in three increments, each compressed firmly and cured for 40 seconds. Fifteen specimens were disassembled 60 seconds after final cure and then tested. The remaining 60 teeth were disassembled 15 seconds after cure; one group was tested at this time and the others immersed in saline at 37 degrees C for 24 hours, 1 week and 4 weeks before being tested. A shear load was applied at a crosshead speed of 0.5 mm/minute, the shear bond strengths calculated and expressed in MPa. Data were analyzed by ANOVA and Student Newman-Keuls test. Class V cavities were prepared at the facial surfaces of 18 extracted human permanent premolars and restored. Microleakage was determined quantitatively by a spectrophotometric dye-recovery method and expressed as mg dye/restoration. RESULTS: Mean +/- SD of the shear bond strength in MPa were 13.07 +/- 3.59 (1 minute), 16.08 +/- 3.12 (15 minutes), 18.17 +/- 3.44 (24 hours), 17.54 +/- 5.35 (1 week), 17.90 +/- 2.61 (4 weeks). The mean +/- SD microleakage was 0.008 +/- 0.04 mg dye/restoration.

Analysis of Variance↗

PubMed1994

Pit and fissure sealant application using a drying agent.

This clinical investigation assessed the retention of pit and fissure sealants with and without the use of a post-etching drying agent in pediatric dental patients. Twenty eight healthy patients with four fully erupted, non-carious first permanent molars participated. Sixteen males and 12 females, 5-12 years of age, each received four sealants, two with and two without a drying agent. Sealants were placed by three dental operators. Assignment for sealant application (with and without drying agent) was based on a computer-generated randomization table. Sealant application involved cleansing of the teeth with a non-fluoridated prophylaxis paste followed by rinsing 60 seconds with air/water spray, enamel conditioning with 40% phosphoric acid for 60 seconds, rinsing with air/water spray for 60 seconds, application of drying agent for 5 seconds, application of sealant material, and light curing for 60 seconds. Modified USPHS (Ryge) criteria were used to evaluate interfacial staining, secondary caries, marginal integrity, and surface texture. Sealant retention was evaluated as fully retained or lost (failed). All 28 participants returned for the 12-month recall visit. Four evaluators reported a 91% overall retention rate. Of the 56 teeth sealed without a drying agent, there was a 13% (n = 7) failure rate compared to 5% (n = 3) failure rate for the 56 teeth sealed with a drying agent. These results were not statistically significant (P > 0.05) based on the log-rank test.

Child↗

PubMed1994

Effectiveness of sealed dental prophylaxis angles inoculated with Bacillus stearothermophilus in preventing leakage.

It was the purpose of this in vitro investigation to evaluate the effectiveness of several brands of sealed, reusable prophylaxis angles to keep internal materials within the internal portions of the head of the prophylaxis angle, and not allowing contaminates to leak out. Three brands of sealed, reusable dental prophylaxis angles were autoclaved and then taken apart under a biocontainment flow hood. Testing conditions were designed to prevent a "worst case scenario" by inoculating dental prophylaxis angles with 10(6) of the heat resistant spores of Bacillus stearothermophilus and 20% bovine serum albumin to simulate the presence of human serum. The concentration of Bacillus stearothermophilus spores was verified before testing procedures were initiated. The internal portions of the sterile prophylaxis angles were inoculated with a 1:1 mixture of the Bacillus stearothermophilus spores and bovine serum albumin, at a concentration of 1.15 x 10(6) spores/inoculation. The prophylaxis angles were reassembled under sterile conditions, and a sterile rubber cup was inserted into each of the prophylaxis angles. The prophylaxis angles were attached to a sterile dental handpiece and then submerged in a 50 ml tube containing sterile trypticase soy broth and run at 3000 rpm for 30 seconds. The tube of medium was incubated for 7 days. No growth of Bacillus stearothermophilus spores could be cultured from one of the brands of prophylaxis angles at any time during the incubation period. The other two brands of prophylaxis angles did produce some leakage of the Bacillus stearothermophilus spores.

Cross Infection↗

PubMed1994

Laboratory evaluation of phosphate ester bonding agents.

Two dentin bonding agents that contain phosphorus esters, (Clearfil Photo Bond and Panavia), and a bonding agent for porcelain, (Clearfil Porcelain Bond), have been introduced for bonding to enamel, dentin, amalgam, cast metal alloys and porcelain. The shear bond strengths were determined to enamel (Procedure A), to dentin (Procedure B), to amalgam (Procedure C), of amalgam to dentin (Procedure D), to cast metal alloy (Procedure E) and to porcelain (Procedure F). Also the quantitative microleakage of Class V restorations in cementum (dentin) was evaluated (Procedure G). The components were applied as directed by the manufacturer and a light-cured resin composite for posterior teeth, (Clearfil Photo Posterior) used. The mean +/- SD of the shear bond strengths recorded in MPa were: A = 24.15 +/- 3.65; B = 11.30 +/- 3.12; C = 13.77 +/- 3.42; D = 4.26 +/- 0.92; E = 17.84 +/- 3.19; F = 13.45 +/- 4.12. The quantitative microleakage (G) was 0.55 +/- 0.34 mg dye/restoration.

Analysis of Variance↗

PubMed1994

Shear bond strength required to prevent microleakage of the dentin/restoration interface.

The purpose of this in vitro study was to determine the relationship between the shear bond strength [SBS] of seven dentin bonding systems to dentin and the quantitative microleakage [ML] of Class V preparations in dentin restored with these systems. The systems evaluated were All-Bond/Bisfil-P [A]; Syntac/Heliomolar [B]; XR-Bond/Herculite [C]; Scotchbond 2/Silux [D]; Denthesive/Charisma [E]; Prisma Universal Bond 2/Prisma AP.H [F]; and Tenure/Perfection [G]. The 115 specimens were removed from the assembly apparatus and stored in saline at 37 degrees C for 24 hours, the SBS determined and expressed in MPa. Fifteen Class V preparations in dentin were restored with each of the bonding systems, thermocycled 500x in 2% methylene blue solution between 50 degrees C and 8 degrees C, and the ML determined by means of a spectrophotometric dye-recovery method. The ML was expressed in microgram dye/restoration. The data were analyzed by ANOVA, Student-Newman-Keuls test, and linear regression analysis. The SBS in MPa were: A:17.2 +/- 3.6; B:15.9 +/- 2.1; C:15.4 +/- 3.7; D:11.6 +/- 2.2; E:10.7 +/- 3.7; F:10.4 +/- 2.5; G:8.2 +/- 3.9. The ML in microgram dye/restoration were: A:2.6 +/- 1.2; B:2.6 +/- 1.0; C:2.2 +/- 1.9; D:3.1 +/- 2.9; E:4.6 +/- 4.2; F:2.6 +/- 2.5; G:4.4 +/- 4.1. SBS = 20.91-2.60 [microgram dye]. The results suggest that a SBS of +/- 21 MPa may reduce ML to near zero.

Analysis of Variance↗

PubMed1994

Laboratory evaluation of the XR-Bond Dentin/Enamel Bonding System.

The shear bond strengths of the XR-Bonding System used in conjunction with Herculite composite, to the dentine of forty extracted human permanent first and second molars were determined after the test specimens were stored in physiological saline at 37 degrees C for 48 hours, one week, two weeks and four weeks, respectively. A shear load was applied to the base of the bonded composite cylinders with a knife-edged rod at a crosshead speed of 0.5 mm/minute. The shear bond strengths were expressed in megapascals (MPa). The quantitative microleakage of Class V preparations in dentine (cementum) in forty-eight extracted human maxillary permanent canines restored with the same dentinal bonding system and after storage in physiological saline at 37 degrees C for the same time intervals as for the shear bond strength tests, was determined. On the final day of each time interval the teeth were thermocycled X 500 in a 2 per cent methylene blue solution between 8 degrees C and 50 degrees C with a dwell time of 15 seconds. Microleakage was determined by a spectrophotometric dye-recovery method and expressed in microgram dye/restoration. There was a significant trend for the shear bond strengths to increase with duration of storage (p = 0.01) but the quantitative microleakage was not significantly different (p = 0.75).

Composite Resins↗

PubMed1993

Dental disease and risk of coronary heart disease and mortality.

OBJECTIVE: To investigate a reported association between dental disease and risk of coronary heart disease. SETTING: National sample of American adults who participated in a health examination survey in the early 1970s. DESIGN: Prospective cohort study in which participants underwent a standard dental examination at baseline and were followed up to 1987. Proportional hazards analysis was used to estimate relative risks adjusted for several covariates. MAIN OUTCOME MEASURES: Incidence of mortality or admission to hospital because of coronary heart disease; total mortality. RESULTS: Among all 9760 subjects included in the analysis those with periodontitis had a 25% increased risk of coronary heart disease relative to those with minimal periodontal disease. Poor oral hygiene, determined by the extent of dental debris and calculus, was also associated with an increased incidence of coronary heart disease. In men younger than 50 years at baseline periodontal disease was a stronger risk factor for coronary heart disease; men with periodontitis had a relative risk of 1.72. Both periodontal disease and poor oral hygiene showed stronger associations with total mortality than with coronary heart disease. CONCLUSION: Dental disease is associated with an increased risk of coronary heart disease, particularly in young men. Whether this is a causal association is unclear. Dental health may be a more general indicator of personal hygiene and possibly health care practices.

Adult↗

PubMed1993

Quantitative microleakage of six dentin bonding systems.

This in vitro study evaluated the quantitative microleakage (ML) of (A) Gluma/Pekafill, (B) Tripton/Opalux, (C) Syntac/Heliomolar, (D) Prisma Universal Bond 2/Prisma AP.H., (E) Prisma Universal Bond 3/Prisma AP.H., and (F) Clearfil PhotoBond/Photo Clearfil Bright to cementum (dentin) by means of a dye-recovery spectrophotometric technique. Standardized cylindrical Class V preparations, 3 mm in diameter and 1.5 mm deep, were made on the facial surfaces of the roots of ninety extracted human maxillary and mandibular permanent canines and the teeth were restored with the recommended resin composite. The root apices were removed, Class V preparations made at the cut apices and restored with two coats of Copalite varnish and amalgam. The teeth were painted with two coats of nail varnish except for 1 mm surrounding the restorations prior to thermocycling x500 in 2% methylene blue solution. Root sections including the restorations were placed in 50% HNO3, the dye extracted and the dye concentrations determined spectrophotometrically. Standard solutions with known amounts of dye were prepared in 50% HNO3 and unrestored root sections placed in these. ML was expressed as micrograms dye/restoration and data analyzed by ANOVA and Duncan's test. The following results were obtained: (A) 3.67 +/- 2.18; (B) 2.76 +/- 1.71; (C) 2.57 +/- 0.97; (D) 2.56 +/- 2.51; (E) 1.21 +/- 0.24; (F) 0.49 +/- 0.20. Clearfil PhotoBond and Prisma Universal Bond 3 showed significantly less microleakage than other systems evaluated.

Analysis of Variance↗

PubMed1993

Shear bond strength and microleakage of All-Bond.

The shear bond strengths (SBS) were determined to enamel etched with Uni-Etch (Procedure A) or treated with the mixed Primer A and B (Procedure B), to dentin treated with the Dentin Conditioner (Procedure C) or etched with All-Etch (Procedure D), to amalgam treated with the mixed Dual Opaquer Base and Catalyst which was allowed to self cure (Procedure E) or light cured (Procedure F), of amalgam to dentin (Procedure G), to cast metal alloy (Procedure H), and to porcelain (Procedure I). The test specimens were stored in physiological saline at 37 degrees C for 24 hours, and the SBS determined by the application of a shear load directed at the base of the bonded composite cylinders at a crosshead speed of 0.5 mm/minute. The SBS were calculated and expressed in MPa. Standardized Class V preparations were made at the facial aspects of the roots of the teeth, treated with the Dentin Conditioner (Procedure J) or etched with All-Etch (Procedure K). Quantitative microleakage (QM) was determined by means of a spectrophotometric dye-recovery method and expressed in microgram dye/restoration. The mean +/- SD of the SBS in MPa were: A: 18.3 +/- 2.1; B: 22.0 +/- 2.9; C: 17.2 +/- 3.6; D: 15.6 +/- 3.7; E: 12.9 +/- 1.9; F: 13.6 +/- 2.0; G: 13.0 +/- 3.5; H: 21.8 +/- 2.6; I: 8.2 +/- 2.8. The mean +/- SD of the QM in microgram dye/restoration were: J: 2.61 +/- 1.22 and K: 1.95 +/- 0.59. The analysis of the SBS data showed that the application of the Primer to enamel resulted in a significant increase in SBS.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1993

Evaluation of the Syntac bonding system.

The purpose of this in vitro study was to determine the shear bond strength [SBS] of Syntac to dentin; to determine the quantitative microleakage (ML) of Class V preparations in dentin restored with the Syntac system; and to study resin penetration into the dentin tubules by SEM. The occlusal surfaces of 30 extracted human mandibular permanent first and second molars were ground wet on 600-grit SiC to expose the superficial dentin. The teeth were embedded in brass tooth cups with cold cure acrylic resin. The Syntac Primer and the Syntac Adhesive were applied to the demarcated bonding sites as recommended by the manufacturer. Radiopaque Heliomolar was transferred to the opening in a split teflon mold in three increments, each compressed firmly and cured for 40 seconds. Fifteen of the test specimens were disassembled 60 seconds after cure [A], and the remainder 15 min after cure and the latter specimens stored in saline at 37 degrees C for 24 hours [B]. A shear load was applied at a crosshead speed of 0.5 mm/min, the SBS calculated and expressed in MPa. The data were analyzed by a two-sample t-test. Class V cavities were prepared on the facial surfaces of 15 human premolars and restored. The ML was determined quantitatively by a spectrophotometric dye recovery method and expressed as microgram dye/restoration. The mean +/- SD of the SBS in MPa were: A: 10.14 +/- 2.80; B: 15.90 +/- 2.13 and the ML 2.57 +/- 0.97 microgram dye/restoration. The SBS recorded after 24 hours storage was significantly greater than after 1 minute (P < 0.0001). The bonding resin penetrated deeply into the dentin tubules.

Composite Resins↗

PubMed1993

Enamel roughness after air-powder polishing.

The purpose of this study was to quantify differences in enamel surface roughness following treatment with an air abrasive system when compared to a rubber cup and pumice. The coronal portion of 40 bovine teeth were tested. Half of the teeth were placed in a control group and cleansed with a rubber cup and pumice, the other half or "test" group were treated with an air-powder polisher. All teeth were exposed to the given cleansing agent for a time equivalent to a 15-year recall program. Pre- and post-treatment surface evaluation was completed using a surface profilometer. In addition, representative samples were evaluated before and after cleansing under the scanning electron microscope (SEM). The results of this study showed no statistically significant increase in enamel surface roughness in teeth cleansed with the air polisher when compared to the roughness of the control teeth. This was confirmed visually by use of SEM taken at magnifications of up to x1000. The findings of this study indicate there is no significant alteration of the enamel surface when a tooth is treated with an air-powder polisher for the equivalent of a 15-year recall program.

Air Pressure↗

PubMed1992

Pediatric nutrition surveillance system--United States, 1980-1991.

The CDC Pediatric Nutrition Surveillance System (PedNSS) monitors the general health and nutritional characteristics of low-income U.S. children who participate in multiple public health programs. This system is intended to characterize trends and patterns in key indicators of nutritional status so that the information can be used for program planning and targeting. The indicators monitored by PedNSS are birth weight, childhood growth status, anemia, and breast-feeding patterns. From 1980 through 1991, the trends for low birth weight, low height-for-age (shortness), low weight-for-height (thinness), and high weight-for-height (overweight) were stable for all children monitored by the PedNSS, with the exception of Asian children, who were predominantly of Southeast Asian refugee background. In the early 1980s, the prevalence of low birth weight and shortness was higher among Asian children than among children of other racial or ethnic groups who were monitored by the PedNSS. However, these prevalences declined steadily from 1980 through 1991. By 1991, the prevalences of low birth weight and shortness for Asian children were similar to those observed for children of other races/ethnic groups. Overall, low-income U.S. children had a slightly lower height-for-age than expected, indicating that some of these children were at a health and nutritional disadvantage. The prevalence of overweight varied among different racial/ethnic groups; Hispanic and Native American children had the highest prevalences of overweight. The 20%-30% prevalence of anemia among low-income children monitored by the PedNSS was higher than among the general population, reflecting in part the preferential enrollment and retention of anemic children by public health nutrition programs and also indicating that many children had inadequate iron nutrition. From 1980 through 1991, the prevalence of anemia declined > 5% for most of the age- and race/ethnicity-specific groups monitored by PedNSS. That decline represents an improvement in iron nutritional status. PedNSS is a useful system for the monitoring and characterization of the nutrition status of low-income children at both state and national levels.

Adolescent↗

PubMed1992

Degradation of microfilled posterior composite.

The substantial improvement in the chemical, physical and mechanical characteristics of posterior composites has contributed to their increased use in recent years. However, some troubling characteristics of these materials are their susceptibility to wear, marginal leakage, and recurrent caries. Numerous studies have dealt with the wear resistance of posterior composites. Only a few have investigated the mechanisms of failure, particularly those containing submicron-sized fillers. The purpose of this study, therefore, was to analyze the clinical characteristics of a posterior composite to determine the mechanisms responsible for marginal degradation. Using a series of optical standards, it was determined that the generalized wear-rate was linear, averaging 8 microns/year. Furthermore, it was shown that the marginal defect was cohesive in nature and that this type of defect, which is inherent in submicron-type posterior composites, was probably due to tensile fatigue failure.

Acrylic Resins↗

PubMed1992

The effect of enamel preparation on the tensile bond strength of orthodontic composite resin.

The bonding of orthodontic brackets to enamel surface using bis-GMA composite resin is usually accomplished by first cleaning the tooth surface then etching with phosphoric acid. This study compared the tensile bond strength of composite resin applied to a tooth surface which had been cleansed with an air-powder polisher to that of the same resin applied to a surface cleansed using a rubber cup and pumice. A wire loop apparatus was attached to bonded orthodontic brackets and pulled in tension in order to test the adherence of the bracket to the tooth. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to evaluate the tooth surface to determine whether sodium bicarbonate material remained after the cleaning operation. All data was analyzed by the one way analysis of variants, the Student-Newman-Keuls test and Duncan's multiple comparison test. No statistical differences were found between the tensile strength of the bonds on the teeth cleansed with the air-powder polisher and those cleansed with a rubber cup and pumice. However, a double exposure of the tooth to phosphoric acid may lower the tensile bond strength by a significant amount.

Acid Etching, Dental↗

PubMed1992

A laboratory study of the Amalgambond Adhesive System.

The shear bond strengths (SBS) of the Amalgambond Adhesive System to several substrates were determined in vitro. Ninety extracted human permanent first and second molars were used. In 30 teeth, the occlusal surfaces were ground wet on 600-grit SiC to expose the enamel and in 60 to expose the superficial dentin. Amalgam (Tytin) restorations were placed on 15 exposed dentin surfaces and sandblasted. The Metafil-A composite was transferred in three increments and each cured for 30 seconds. The SBS of the composite to enamel were determined 1 minute (A) and 24 hours after final cure (B); to dentin 1 minute (C) and 24 hours after final cure (D); of freshly mixed amalgam to dentin (E) and to previously placed amalgam (F) after 24 hours. All of the 24 hours specimens were stored in saline at 37 degrees C or 24 hours. A shear load was applied to the base of the bonded cylinders with a knife-edged rod in an Instron machine at a crosshead speed of 0.5 mm/min. The SBS were expressed in MPa and the data analyzed by Student t-test, ANOVA and Student-Newman-Keuls test. The mean +/- SD of SBS were: A: 8.15 +/- 1.74; B: 15.69 +/- 4.50; C: 6.64 +/- 1.72; D: 17.09 +/- 4.61; E: 5.10 +/- 1.73; F: 6.54 +/- 3.78. The SBS to enamel and to dentin, respectively, after 24 hours were significantly greater than after 1 minute (P = 0.0001), the SBS of A vs C (P = 0.1783), B vs D (P = 0.2180) and E vs F (P = 0.7149) were not significantly different.

Analysis of Variance↗