Biomedical subjects

D H Retief

Publications and source records attributed to D H Retief.

At least 19 recordsLinked to original sources

PubMed1998

In vitro enamel and cementum fluoride uptake from three fluoride-containing composites.

The incorporation of fluoride into restorations is desirable because of its cariostatic action. The purpose of this study was to determine fluoride release and fluoride uptake by enamel and cementum from three visible light-cured fluoride-containing composites. Seven circular discs of each composite were prepared and the amount of fluoride released into distilled water was determined at daily intervals for 14 days and then after 30, 60 and 90 days. The fluoride concentration in enamel and cementum was determined in three successive depths by an acid etch biopsy procedure. The composite slabs were made and ligated to the enamel and cementum surfaces and the teeth were immersed in synthetic saliva for 7 days. After removal of the composite slabs, three successive biopsies were again performed. Then the teeth were immersed in 1 M KOH for 24 h and similar biopsies done. The fluoride concentrations were adjusted to standardized depths of 10microm, and the total and bound fluoride uptake calculated. The amounts of fluoride released were significantly different among the three composites. The fluoride released decreased sharply after 1 day and then gradually reached a plateau. As for the enamel and cementum fluoride uptake, FluorEver showed the largest uptake followed by FluoroCore and then Pertac-Hybrid.

Acid Etching, Dental↗

PubMed1996

Shear bond strengths of two commercially available dentine-amalgam bonding systems.

OBJECTIVES: The purpose of this in vitro study was to determine the shear bond strengths (SBS) of amalgam to dentine treated with the Amalgambond Plus System (AM) and All-bond 2 System (AL) after storage periods in physiological saline for up to 48 weeks. METHODS: The occlusal superficial dentine surfaces of 150 extracted human molars were exposed by wet grinding on 600-grit silicon carbide and the bonding area demarcated with a perforated adhesive tape. Freshly mixed Tytin amalgam was transferred to the opening in a split Teflon mold on the demarcated dentine surfaces treated with either AM or AL as directed by the manufacturers. The SBS of AM after 24 h (A), 4 weeks (B), 12 weeks (C), 24 weeks (D), and 48 weeks (E), and of AL after 24 h (F), 4 weeks (G), 12 weeks (H), 24 weeks (I), and 48 weeks (J), were determined with a knife-edged rod at a crosshead speed of 0.5 mm/min and expressed in megapascal (MPa). The data were analyzed by ANOVA and Student's t-test. RESULTS: The mean +/- SD of SBS in MPa were: A: 14.6 +/- 4.0; B: 14.5 +/- 3.6; C: 15.3 +/- 4.8; D: 14.6 +/- 4.6; E: 13.9 +/- 4.0; F: 9.5 +/- 4.7; G: 12.1 +/- 1.7; H: 10.2 +/- 3.5; I: 12.0 +/- 3.9; J: 11.9 +/- 3.5. The SBS of the five groups treated with AM (A, B, C, D and E) were not significantly different (P > 0.05) and the SBS of the five groups treated with AL (F, G, H, I and J) were not significantly different (P > 0.05). The SBS of A vs. F, B vs. G, ad C vs. H, were significantly different (P < 0.05), but D vs. I and E vs. J were not significantly different (P > 0.05). CONCLUSION: The SBS of amalgam to dentine treated with AM and AL were not adversely affected by the duration of storage.

Analysis of Variance↗

PubMed1995

Shear bond strength and quantitative microleakage of a multipurpose dental adhesive system resin bonded to dentin.

The shear bond strengths of a dental bonding system used in conjunction with a composite resin bonded to dentin were determined 1 minute after irradiation and after storage in saline at 37 degrees C for 24 hours, 1 week without and with temperature cycling, and 4 weeks without and with temperature cycling. The quantitative microleakage of class V preparations in cementum (dentin) restored with the system was determined by a spectrophotometric dye-recovery method. Excellent shear bond strengths ranging from 13.9 MPa (1 minute) to 19.5 MPa (1 week) were obtained. The shear bond strengths and quantitative microleakage of the multipurpose dental adhesive system compared favorably with the data obtained from other dental bonding systems under similar experimental conditions.

Analysis of Variance↗

PubMed1995

Laboratory evaluation of the Gluma 3-step bonding system.

PURPOSE: To determine in vitro (1) the shear bond strengths (SBS) of the modified Gluma system to enamel and dentin; (2) the qualitative and the quantitative microleakage (ML) of Class V preparations on the cemento-enamel junction (CEJ) and in dentin, respectively, restored with the Gluma system; and (3) the effect of the system's components on enamel and dentin by scanning electron microscopy. MATERIALS AND METHODS: Seventy-five extracted human maxillary permanent central incisors and 75 permanent first and second molars were embedded in brass tooth cups with cold-cure acrylic resin. The facial surfaces of the anterior and the occlusal surfaces of the molar teeth were ground wet on 180- followed by 600-grit silicon carbide paper. Demarcated sites on the surfaces were treated according to the manufacturer's instructions and Pekafill composite was bonded to the treated surfaces. Fifteen specimens prepared on enamel were removed 1 minute after cure (A) and the SBS determined. The remaining specimens were removed 15 minutes after final cure, stored in saline at 37 degrees C for 24 hours (B), for 1 week without (C) and with temperature cycling (D), and for 4 weeks (E). Similar regimens were used for dentin, groups F, G, H, I and J. The SBS were determined and expressed in MPa. The data were analyzed by ANOVA, Student-Newman-Keuls and t-tests. For the qualitative ML evaluation, Class V cavities were prepared on the CEJ of 30 human premolars and restored with Gluma/Pekafill. After thermocycling in 0.5% basic fuchsin, the teeth were sectioned and ranked according to the degree of microleakage. Class V cavities were prepared on the facial root surfaces of 15 human premolars and restored. The ML was determined quantitatively by a spectrophotometric dye-recovery method and expressed as microgram dye/restoration. RESULTS: The mean +/- SD of the SBS in MPa were: A: 14.6 +/- 2.2; B: 21.2 +/- 1.6; C: 20.5 +/- 1.4; D: 24.2 +/- 2.0; E: 22.8 +/- 3.7; F: 7.0 +/- 2.0; G: 16.1 +/- 4.0; H: 15.6 +/- 3.7; I: 10.9 +/- 3.3; J: 14.4 +/- 3.3. The quantitative ML was 1.00 +/- 0.39 microgram dye/restoration. The lowest SBS were obtained on specimens tested after 1 minute. Temperature cycling had a significantly adverse effect on the SBS to dentin (P = 0.0003). Etch patterns conducive to bonding were produced on the enamel. The resin system penetrated into the dentin tubules.

Analysis of Variance↗

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

Glass ionomer cement surface protection.

PURPOSE: To evaluate the effectiveness of various surface treatments for glass ionomer cement (GIC) by determining quantity of dye uptake spectrophotometrically. MATERIALS AND METHODS: Sixty specimens, 4.5 mm diameter and 2 mm thick, were made from Shofu GIC and divided into 10 groups. Positive control (A) and negative control (B) specimens were not protected while experimental specimens were protected with ARM chemically-cured bonding resin (C), Durafill Bond light-cured bonding resin (D), Bondlite light-cured bonding resin (E), Colorama nail varnish (F), Shofu varnish (G), Copalite varnish (H), Vaseline (I) or Vaseline followed by Copalite (J). The discs were immersed in 0.05% methylene blue solution 10 minutes after mixing except group B specimens which were immersed in deionized water. After 24 hours the discs were removed, washed, and individually placed in 1 ml 65% nitric acid for 36 hours. The solutions were filtered, centrifuged and the absorbance determined spectrophotometrically at 590 nm. Dye uptake was expressed in microgram dye/restoration and the data analyzed by ANOVA and Tukey Kramer test. RESULTS: The mean (SD) of dye uptake were: A:95.12 (11.28); B:0 (0); C:40.90 (5.06); D:33.89 (3.63); E:35.73 (3.36); F:3.29 (0.79); G:14.87 (2.86); H:21.99 (3.25); I:47.21 (7.06); J:29.74 (3.49). All the surface agents were effective in protecting setting restorative glass ionomer cement, but nail varnish provided the best results.

Analysis of Variance↗

PubMed1994

Laboratory evaluation of experimental restorative systems containing 4-META.

PURPOSE: To determine the in vitro shear bond strengths and quantitative microleakage of four experimental bonding restorative systems used in conjunction with Metafil-A, an experimental composite that does not contain 4-META, and Metafil-Ex, a 4-META containing experimental composite. MATERIALS AND METHODS: 120 test specimens were prepared on dentin treated with Amalgambond Activator followed by the application of an experimental primer consisting of 35% glyceryl methacrylate. In 60 teeth the mixed Amalgambond Base and Catalyst was then applied while in the remaining 60 teeth this step was omitted. Cylinders of either Metafil-A or Metafil-Ex were bonded to the dentin surfaces and the test specimens removed from the assembly apparatus after 1 minute or after 15 minutes and the latter specimens were stored in saline at 37 degrees C for 24 hours prior to determining the shear bond strength in an Instron machine at a crosshead speed of 0.5 mm/minute. Sixty Class V preparations were made on the facial surfaces of the roots of extracted human premolars and the preparations restored with the four restorative systems. The quantitative microleakage was determined by a spectrophotometric dye-recovery method. RESULTS: The shear bond strengths were significantly lower when the 4-META-containing Amalgambond Base and Catalyst were not applied and were unmeasurable when Metafil-A was used as the composite. The quantitative microleakage of the latter system was significantly greater than when the other restorative systems were used.

Acrylic Resins↗

PubMed1994

Do adhesives prevent microleakage?

All the polymeric composite restorative resins shrink during polymerisation resulting in the development of tensile and/or shear stresses at the tooth/restoration interface. The major part of the contraction stresses develops within 15 minutes after the initiation of polymerisation but with the light activated resins it occurs within seconds after irradiation. The tensile stresses may disrupt the adhesive bonding of the restorative system to the cavity walls resulting in microleakage at the tooth/restoration interface. The properties of the restorative resins which include polymerisation shrinkage during hardening, differences in the coefficients of thermal expansion of the tooth and the restoration, and water sorption of the restoration on exposure to the oral environment, play an important role in determining the marginal gap dimensions and hence microleakage. Microleakage at the enamel/restoration interface has been eliminated by the acid etch technique provided that adequate enamel thickness is present. Microleakage at the dentine/restoration interface, however, is much more difficult to eliminate. None of the dentinal bonding restorative systems eliminates microleakage at the gingival margins of restorations that extend to or beyond the cementum/enamel junction. Microleakage is reduced by using an incremental restorative technique but is increased when the restored teeth are subjected to masticatory stress or occlusal loading. None of the dentinal bonding systems prevents the development of marginal gaps at the dentine/restoration interface when evaluated 10 minutes after placement of the restorations but hygroscopic expansion resulting from water or saline immersion results in a significant reduction in marginal gap dimensions. An increase in the cavosurface margins reduces marginal gap dimensions but it is not dependent on cavity depth.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗

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 strengths of composite to chlorhexidine-treated enamel.

This study determined the shear bond strength (SBS) of composite bonded to chlorhexidine-treated enamel and untreated enamel. Fifty human molars were mounted in cold- cure acrylic and the superficial enamel of the buccal or lingual surface was exposed using 600-grit silicon carbide paper. During the experimental protocol, the control group (n = 25) and the experimental group (n = 25) were stored in distilled water at 37 degrees C. The experimental group was immersed in 0.12% chlorhexidine gluconate for 1 minute, 4 times daily, for 7 days. Prisma APH composite was then bonded to all samples following acid etching for 30 seconds, and the SBS was determined. Shear bond strengths for the control (13.23 +/- 3.22 MPa) and the experimental (13.67 +/- 4.59 MPa) groups were not significantly different using a t-test. The result may be attributed to either a lack of effect of chlorhexidine or to the acid etch which dissolves the affected superficial enamel leaving an unaffected substrate for bonding.

Acid Etching, Dental↗

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

Quantitative microleakage of some dentinal bonding restorative systems.

The quantitative microleakage of class V cementum (dentin) cavities restored with six dentinal bonding restorative systems was determined in vitro. Ninety extracted human permanent first and second mandibular and maxillary premolars were used in this study. Class V preparations were made in cementum (dentin) at the root facial surfaces. The preparations were restored with 1) a dentin bonding system containing 2% HEMA and BisGMA and a light-cured microfilled composite; 2) the same materials only substituting META/MMA base and TBB catalyst monomers for the BisGMA sealer; 3) a dentin bonding system containing 35% HEMA with META/MMA base and TBB catalyst, and a light-cured hybrid composite; 5) the same dentin bonding system only substituting the 35% glycerylmethacrylate for the 35% HEMA and using the microfilled composite; and 6) the previously described system with a substitution of 0.5 mol EDTA for the 10% citric acid -3% FeCl3. Fifteen teeth were restored with each procedure. The restorations were finished with 12-bladed carbide burs 15 min after placement, the teeth were stored in saline at 37 degrees C for 24 h, finished with Sof-Lex discs and then thermocycled in 2% methylene blue solution 500 times between 50 degrees C and 8 degrees C with a dwell time of 15 s. Quantitative microleakage was determined by a spectrophotometric dye-recovery method and expressed in microgram/dye/restoration. The data were analyzed by ANOVA, Student-Newman-Keuls and Kruskal-Wallis tests. The quantitative microleakage of the teeth restored with the adhesive systems containing 35% glyceryl methacrylate was significantly reduced. The bonding mechanism of glyceryl methacrylate is not known.

Analysis of Variance↗

PubMed1993

The 48-month increment of root caries in an urban population of older adults participating in a preventive dental program.

The purpose of this study was to determine the effect of a 48-month preventive dental program on the incidence of root caries in an urban, geriatric, noninstitutionalized population residing in an optimally fluoridated area. The 466 participants were randomly assigned to one of three groups at baseline. Group A (control): 171 subjects using a placebo mouthrinse daily; group B: 147 subjects receiving semiannual applications of a topical APF gel (1.2% F-) with the daily use of a placebo mouthrinse; group C: 148 subjects using a fluoridated mouthrinse daily, ACT (0.05% F-). At baseline, the numbers of surfaces at risk, and decayed and filled surfaces were recorded. After 48 months, in addition, the number of reversed and new lesions were determined, and the incremental DMFS calculated. The data were analyzed by ANCOVA. The incremental DMFS were: A = 0.91, B = 0.27, C = 0.26. The incremental DMFS in groups B and C were significantly lower than in group A (P < .05). The number of reversed lesions in group C (1.53 +/- 2.03) was significantly greater than in group A (1.11 +/- 1.74) and group B (1.01 +/- 1.86) (P < .05). The number of new lesions in group B (1.36 +/- 2.00) was significantly less than in group A (1.99 +/- 2.65) (P < .05). The daily use of the fluoride mouthrinse significantly increased the number of reversed lesions.

Acidulated Phosphate Fluoride↗

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

Natural and induced radiation caries: A SEM study.

Radiation caries is a well-known indirect side effect of head and neck radiotherapy. The initiation and progression of radiation caries were studied using an in situ model. The morphology of induced carious lesions was compared with that of natural radiation caries. Both natural and induced radiation caries showed the same patterns of decay; widespread areas with porosity of enamel, crater formation with exposure of subsurface enamel, preferential dissolution of prisms with hollowing out of prism cores, loss of large parts of surface enamel and loss of full enamel coverage exposing the underlying dentin. In irradiated patients most enamel slabs were severely demineralized within 6 weeks whereas in control subject the slabs showed no significant demineralization after 12 weeks. The model may offer an excellent opportunity to study preventive fluoride regimens because of the rapid induction of radiation caries and its similarity with natural lesions.

Adult↗

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↗