Correlation of ultrasound microscopy and Vickers hardness measurements of human dentin and enamel - A pilot study.

OBJECTIVE: To investigate if Vickers microhardness of dentin and enamel correlated with acoustic velocity c(l) or acoustic reflection from the sample's top (amplitude). METHODS: Eight transversal sections of a sound human tooth were investigated with scanning acoustic microscopy (SAM) and Vickers microhardness measurements. Longitudinal acoustic velocity c(l), amplitude and microhardness MHV were evaluated and for each c(l) test point corresponding amplitude and MHV were linearly interpolated and graphically analyzed. Spearman rank order correlation (rS) was calculated (p<0.05). RESULTS: c(l) was predominantly 6100-7000ms-1 in enamel and 3800-4600ms-1 in dentin and correlated significantly with MHV with 27-420 in enamel and 20-90 in dentin (rs=0,57). Amplitudes significantly correlated with MHV, too, but even better (rs=0,77). SIGNIFICANCE: Acoustic velocity and amplitudes were appropriate to detect microhardness differences of dentin and enamel and certain value ranges of both could be assigned to certain MHV ranges. Further research is needed to differentiate more precisely between the different hard tooth tissues.

Contact angle and surface free energy of experimental resin-based dental restorative materials after chewing simulation.

OBJECTIVE: To investigate contact angle and surface free energy of experimental dental resin composites containing novel delivery systems of polymeric hollow beads and low-surface tension agents after chewing simulation test. METHODS: A delivery system of novel polymeric hollow beads differently loaded with two low-surface tension agents was used in different amounts to modify commonly formulated experimental dental resin composites. The non-modified resin was used as standard. Surface roughness Ra, contact angle Θ, total surface free energy γS, its apolar γS(LW), polar γS(AB), Lewis acid γS(+) and base γS(-) terms were determined and the results prior to and after chewing simulation test were compared. Significance was p<0.05. RESULTS: After chewing simulation Ra increased, Θ decreased, Ra increased for two test materials and γS decreased or remained constant for the standard or the test materials after chewing simulation. Ra of one test material was higher than of the standard, Θ and γS of the test materials remained lower than of the standard and, indicating their highly hydrophobic character (Θ≈60-75°, γS≈30mJm(-2)). γS(LW), and γS(-) of the test materials were lower than of the standard. Some of the test materials had lower γS(AB) and γS(+) than of the standard. SIGNIFICANCE: Delivery systems based on novel polymeric hollow beads highly loaded with low-surface tension agents were found to significantly increase contact angle and thus to reduce surface free energy of experimental dental resin composites prior to and after chewing simulation test.

Bacterial viability and physical properties of antibacterially modified experimental dental resin composites.

PURPOSE: To investigate the antibacterial effect and the effect on the material properties of a novel delivery system with Irgasan as active agent and methacrylated polymerizable Irgasan when added to experimental dental resin composites. MATERIALS AND METHODS: A delivery system based on novel polymeric hollow beads, loaded with Irgasan and methacrylated polymerizable Irgasan as active agents were used to manufacture three commonly formulated experimental resin composites. The non-modified resin was used as standard (ST). Material A contained the delivery system providing 4 % (m/m) Irgasan, material B contained 4 % (m/m) methacrylated Irgasan and material C 8 % (m/m) methacrylated Irgasan. Flexural strength (FS), flexural modulus (FM), water sorption (WS), solubility (SL), surface roughness Ra, polymerization shrinkage, contact angle Θ, total surface free energy γS and its apolar γS (LW), polar γS (AB), Lewis acid γS (+)and base γS (-) term as well as bacterial viability were determined. Significance was p < 0.05. RESULTS: The materials A to C were not unacceptably influenced by the modifications and achieved the minimum values for FS, WS and SL as requested by EN ISO 4049 and did not differ from ST what was also found for Ra. Only A had lower FM than ST. Θ of A and C was higher and γS (AB) of A and B was lower than of ST. Materials A to C had higher γS (+) than ST. The antibacterial effect of materials A to C was significantly increased when compared with ST meaning that significantly less vital cells were found. CONCLUSION: Dental resin composites with small quantities of a novel antibacterially doped delivery system or with an antibacterial monomer provided acceptable physical properties and good antibacterial effectiveness. The sorption material being part of the delivery system can be used as a vehicle for any other active agent.

Shear bond strength and fracture analysis of human vs. bovine teeth.

PURPOSE: To evaluate if bovine enamel and dentin are appropriate substitutes for the respective human hard tooth tissues to test shear bond strength (SBS) and fracture analysis. MATERIALS AND METHODS: 80 sound and caries-free human erupted third molars and 80 freshly extracted bovine permanent central incisors (10 specimens for each group) were used to investigate enamel and dentine adhesion of one 2-step self-etch (SE) and one 3-step etch and rinse (E&R) product. To test SBS the buccal or labial areas were ground plane to obtain appropriate enamel or dentine areas. SE and E&R were applied and SBS was measured prior to and after 500 thermocycles between +5 and +55°C. Fracture analysis was performed for all debonded areas. RESULTS: ANOVA revealed significant differences of enamel and dentin SBS prior to and after thermocycling for both of the adhesives. SBS- of E&R-bonded human enamel increased after thermocycling but SE-bonded did not. Bovine enamel SE-bonded showed higher SBS after TC but E&R-bonded had lower SBS. No differences were found for human dentin SE- or E&R-bonded prior to or after thermocycling but bovine dentin SE-bonded increased whereas bovine dentine E&R-bonded decreased. Considering the totalized and adhesive failures, fracture analysis did not show significances between the adhesives or the respective tooth tissues prior to or after thermocycling. CONCLUSION: Although SBS was different on human and bovine teeth, no differences were found for fracture analysis. This indicates that solely conducted SBS on bovine substrate are not sufficient to judge the perfomance of adhesives, thus bovine teeth are questionnable as a substrate for shear bond testing.

Bacterial viability on surface-modified resin-based dental restorative materials.

UNLABELLED: The purpose of the present investigation was to investigate the viability of early colonizers on the surfaces of resin-based dental restorative materials modified with low-surface tension active agents in comparison with the unmodified material. A novel polymeric sorption material, loaded with two low-surface tension γ(L) active agents (hydroxyfunctional polydimethylsiloxane and polydimethylsiloxane) or a polymerizable active agent (silicone polyether acrylate), was used to modify commonly formulated experimental dental resin composites. The non-modified resin was used as the standard (ST). The viability of Actinomyces naeslundii, Actinomyces viscosus, Streptococcus mitis, Streptococcus oralis, and Streptococcus sanguinis on water-stored, polished, and human saliva pellicle-coated specimens was determined using a fluorescence microscope after 8 and 24h. Total, vital, and non-vital cells were calculated from the microscopic images by counting pixels per colour. Means, standard deviations, univariate ANOVA and multiple comparisons with post hoc Scheffé's tests were calculated. t-Test was done to compare 8-h and 24-h bacteria counts. For all tests p<0.05 was chosen. NULL HYPOTHESIS: the test materials and the standard did not differ either in the total bacterial counts or in the respective bacterium's viability after 8 or 24h. The test materials modified with the silicone polyether acrylate showed lower total bacteria count after 8 or 24h than ST. But all test materials had significantly fewer vital cells after 8 or 24h compared to ST. The contact angle did not influence bacterial adhesion, but low total SFE and a low polar term of SFE resulted in fewer bacteria. The material's chemistry also affected the total and vital cell counts. Different bacteria viabilities needed to be explored to obtain relevant information regarding bacterial adhesion on dental composite resins. The novel sorption material loaded with low γ(L) active agents or with a low γ(L) polymerizable silicone polyether acrylate used to modify the chemistry of the test materials was appropriate to reduce bacterial adhesion or cell viability, respectively.

A new approach to influence contact angle and surface free energy of resin-based dental restorative materials.

The purpose of the present study was to identify novel delivery systems and active agents which increase the water contact angle and reduce the surface free energy when added to resin-based dental restorative materials. Two delivery systems based on zeolite or novel polymeric hollow beads (Poly-Pore), loaded with two low surface tension active agents (hydroxy functional polydimethylsiloxane and polydimethylsiloxane) or a polymerizable active agent (silicone polyether acrylate) were used to modify commonly formulated experimental dental resin composites. The non-modified resin was used as a standard (ST). Flexural strength, flexural modulus, water sorption, solubility, polymerization shrinkage, surface roughness Ra, contact angle θ, total surface free energy γS, and the apolar γSLW, polar γSAB, Lewis acid γS+ and base γS- components, and the active agents surface tensions γL were determined (P<0.05). The active agents did not differ in γL. The modified materials had significantly higher θ but significantly lower γS, γSAB and γS- than the ST. A Poly-Pore/polydimethyl siloxane delivery system yielded the highest θ (110.9±3.5°) acceptable physical properties and the lowest values for γSLW and γS-. Among the modified materials the polymerizable materials containing active agents had the lowest γAB and the highest γS+ and γS-. Although not significant, both of the zeolite delivery systems yielded higher γSLW, γS+ and γS- but lower γSAB than the Poly-Pore delivery systems. Poly-Pore based delivery systems highly loaded with low surface tension active agents were found not to influence the physical properties but to significantly increase the water contact angle and thus reduce surface free energy of dental resin composites.

Physical properties of self-, dual-, and light-cured direct core materials.

The objective of this study is to evaluate flexural strength, flexural modulus, compressive strength, curing temperature, curing depth, volumetric shrinkage, water sorption, and hygroscopic expansion of two self-, three dual-, and three light-curing resin-based core materials. Flexural strength and water sorption were measured according to ISO 4049, flexural modulus, compressive strength, curing temperature, and curing depth according to well-proven, literature-known methods, and the volumetric behavior was determined by the Archimedes' principle. ANOVA was calculated to find differences between the materials' properties, and correlation of water sorption and hygroscopic expansion was analysed according to Pearson (p < 0.05). Clearfil Photo Core demonstrated the highest flexural strength (125 ± 12 MPa) and curing depth (15.2 ± 0.1 mm) and had the highest flexural modulus (≈12.6 ± 1.2 GPa) concertedly with Multicore HB. The best compressive strength was measured for Voco Rebilda SC and Clearfil DC Core Auto (≈260 ± 10 MPa). Encore SuperCure Contrast had the lowest water sorption (11.8 ± 3.3 µg mm(-3)) and hygroscopic expansion (0.0 ± 0.2 vol.%). Clearfil Photo Core and Encore SuperCure Contrast demonstrated the lowest shrinkage (≈2.1 ± 0.1 vol.%). Water sorption and hygroscopic expansion had a very strong positive correlation. The investigated core materials significantly differed in the tested properties. The performance of the materials depended on their formulation, as well as on the respective curing process.

Effect of Energy Density on the Physical Properties of Resin-Based Restorative Materials when Polymerized with Quartz-Tungsten Halogen or LED-Light.

OBJECTIVES: The purpose of this study was to evaluate flexural strengths, moduli, and maximum deflection of Clearfil AP-X (APX) and Ceram-X Mono (CXM) when cured with a quartz-tungsten halogen (QTH) or an LED-light (LED). METHODS: Specimens were made according to ISO 4049 and cured with QTH or LED for 10, 20 or 60s. Flexural strength, modulus, and deflection were determined after 24 h water storage at 37 degrees C and after thermocycling. Statistical significance was P<.05. RESULTS: Flexural strength did not depend on energy density or curing light and was significantly higher for APX than for CXM but decreased after thermocycling for both materials. Modulus and deflection depended on energy density. Modulus was significantly higher for APX than for CXM and increased for APX but decreased for CXM after thermocycling. Deflection decreased with increasing energy density and decreased after thermocycling. Though energy density did not influence flexural strength, it positively correlated with flexural modulus and negatively with maximum deflection. CONCLUSIONS: Energy density did not influence flexural strength but modulus and deflection. Thermocycling affected all material properties. The LED was as effective as the QTH.

Impact of replacing Bis-GMA and TEGDMA by other commercially available monomers on the properties of resin-based composites.

PURPOSE: To evaluate important material properties of six experimental resin-based restorative materials (EXP) with systematically modified resin matrices using conventional and alternative monomers in comparison with an experimental standard (ST). MATERIALS AND METHODS: Commercially available monomers were selected according to their molecular weight, functionality, viscosity, and polymerization shrinkage. ST, 71wt% filler, matrix UDMA/Bis-GMA/TTEGDMA and six EXPs with modified organic matrices but the same filler content were manufactured. Flexural strength, flexural modulus, water sorption, solubility and polymerization shrinkage of all EXPs were measured and compared with the results of ST. RESULTS: ANOVA (p<0.05) revealed significant differences among the materials and all investigated properties. Bis-GMA and UDMA were substituted by alternative monomers without losing flexural strength or modulus. Replacing the diluting monomer TTEGDMA with alternative monomers resulted in increased flexural strength. None of the experimental products with modified matrices showed increased water sorption or solubility but some even performed better than ST. Increased hygroscopic expansion and reduced shrinkage were achieved using a very hydrophilic monomer but no significant differences of water sorption and solubility in comparison with ST were found. CONCLUSION: The results indicated that there are monomers commercially available providing the same or even better properties than conventional matrices.

Effect of exposure time on the color stability of resin-based restorative materials when polymerized with quartz-tungsten halogen and LED light.

The objective of this study was to investigate the effect of exposure time on color stability of resin-based restorative materials when polymerized with quartz-tungsten halogen light (QTH) or light-emitting diode light (LED). Eight samples of Ceram-X Mono, Dyract eXtra, and Tetric EvoCeram each were cured for 10, 20, and 60 s with QTH or LED. The CIE-Lab values (L*, a*, b*) were measured prior to and after performing water storage or a Suntest, and ΔL, Δa, Δb, and ΔE were calculated. Statistical analysis (p < 0.05) showed significant changes of the color values after each of the aging processes as well as between ΔL, Δa, Δb, and ΔE of the materials in dependence of the curing device, exposure time, aging condition, and material formulation. LED performed similarly or even better with 10-s exposure time than QTH with 20 s. No improvement of color stability was achieved with increasing exposure time of 60 s either for LED or for QTH. Exposure time, emission spectrum of the light-curing device, as well as the individual material formulation influence color stability. There is apparently an exposure time above which the individual material formulation, especially type and amount of photoinitiator or synergist, dominate the color stability.

The effect of different bonding techniques on ceramic/ resin shear bond strength.

PURPOSE: To investigate the effect of different adhesives on the shear bond strength between a feldspathic machinable ceramic and a luting resin. MATERIALS AND METHODS: Seven groups of 20 ceramic specimens each were machined from Vita Mark II blocs. Their surfaces were uniformly treated with 1000-grit paper. Group 1 (control) was hydrofluoric-acid etched for 60 s, group 2 abraded with CoJet, and group 3 PyrosilPen-treated and silanized. Groups 4 and 5 were hydrofluoric-acid etched for 60 s and silanized with two experimental silanes. Variolink II was used as the luting resin for groups 1 to 5. Group 6 and 7 were phosphoric-acid etched for 15 s. Then group 6 was treated with Nexus and group 7 with the Panavia F 2.0 system. All specimens were stored dry for 24 h at 37 degrees C. Shear bond strength was measured prior to and after 5000 thermocycles (TC) between 5 degrees C and 55 degrees C in water. ANOVA was performed with p < or = 0.05. RESULTS: Shear bond strength values 24 h / TC in MPa (SD) were as follows: group 1: 11 (3.0)/ 12 (5.3), group 2: 22 (3.9) / 25 (7.3), group 3: 26 (9.0) / 30 (8.0), group 4: 12 (5.9) / 8 (2.0), group 5: 8 (2.4) / 7 (3.4), group 6: 16 (6.1) / 3 (1.6) and group 7: 16 (8.6) / 16 (4.3). Cojet (24 h, p < or = 0.0007 / TC, p < or = 0.0001) and PyrosilPen (24 h, p < or = 0.0001/ TC, p < or = 0.0001) showed significantly higher bond strength than the control but did not differ significantly from each other. No significant differences between the control and groups 4, 5, 6, and 7 were found. PyrosilPen (p < or = 0.0001) significantly performed best prior to and after TC. Bond strength of experimental silane A (p < or = 0.0499) and Nexus (p < or = 0.0002) significantly decreased after TC. CONCLUSION: Silicoating technology and tribochemistry are fast, trouble-free, and effective surface treatment methods for achieving very good bond strength between feldspathic ceramics and luting resins. Etching with H2F2 can thus be avoided.

In vitro effect of light-emitting diode light polymerization on the color stability of three resin-based restorative materials.

OBJECTIVE: To investigate the color stability of resin-based restorative materials when polymerized with light-emitting diode (LED) curing light in the constant or exponential mode. MATERIAL AND METHODS: Eight specimens of Admira (AD), Compoglass F (CO), and Tetric EvoCeram (TE) constantly cured or exponentially cured with a high-powered LED curing light for 10, 20, or 60 s. The CIE-Lab values (L*, a*, b*) were measured prior to and after performing the water storage or color stability test according to EN ISO 7491 (Suntest). RESULTS: Statistical analysis showed significant changes in the color values after each of the aging processes, as well as between DeltaL, Deltaa, Deltab, and DeltaE of the materials, which were dependent on curing time, mode, and aging condition (p<0.05). CO performed very well during water storage, but AD and TE exceeded the clinically relevant limit DeltaE=1. After the Suntest and 180 d additional water storage, TE showed the highest mean (SD) DeltaE=4.4 (1.1) to 5.4 (1.9). Although AD and CO performed best in the constant mode, they exceeded DeltaE=1. All materials shifted to more red. CONCLUSIONS: The extent of discoloration depended on (a) the curing mode, (b) the curing time, and (c) the aging condition. Not all materials performed clinically acceptably in all tests; TE even showed unacceptable DeltaE>3.3. The optimal curing time was 20 s for both curing modes and all tested materials.

Polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials--a comparative study.

OBJECTIVES: To investigate the polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials. METHODS: The densities of SureFil (SU), CeramXMono (CM), Clearfil AP-X (CF), Solitaire 2 (SO), TetricEvoCeram (TE), and Filtek P60 (FT) were measured using the Archimedes' principle prior to and 15min after curing for 20, 40 and 60s and after 1h, 24h, 7 d, and 30 d storage at 37 degrees C in water. Volumetric changes (DeltaV) in percent after polymerization and after each storage period in water were calculated from the changes of densities. Water sorption and solubility were determined after 30 d for all specimens and their curing times. Two-way ANOVA was calculated for shrinkage and repeated measures ANOVA was calculated for hygroscopic expansion (p<0.05). RESULTS: DeltaV depended on filler load but not on curing time (SU approximately -2.0%, CM approximately -2.6%, CF approximately -2.1%, SO approximately -3.3%, TE approximately -1.7%, FT approximately -1.8%). Hygroscopic expansion depended on water sorption and solubility. Except for SU, all materials showed DeltaV approximately +1% after water storage. CONCLUSION: Polymerization shrinkage depended on the type of resin-based filling material but not on curing time. Shrinkage was not compensated by hygroscopic expansion.

Preparation of the coronal and middle third of oval root canals with a rotary or an oscillating system.

OBJECTIVES: To comparatively evaluate the preparation of oval root canals with a rotary or an oscillating system. STUDY DESIGN: The middle and coronal parts of 55 extracted permanent teeth with oval canals were prepared using FlexMaster (FM) rotary NiTi instruments and EndoEze AET (EE) stainless steel oscillating instruments. Pre- and postoperative images of cross-sections were superimposed to identify shifts in the center and to assess the percentage of untreated regions. In addition, the middle segment was investigated by scanning electron microscope (SEM) to determine debris and smear layer removal. RESULTS: The systems did not significantly differ in the shifts of the canal centers in the middle part of the root. Only a few of the preparations yielded an excellent result with no uninstrumented canal wall left. The SEM investigation demonstrated poor results for both systems regarding debris and smear layer removal, but no significant differences could be observed. CONCLUSIONS: Neither FM nor EE was capable of completely preparing oval root canals.

Water sorption and solubility of contemporary resin-based filling materials.

PURPOSE: Evaluation of water sorption and solubility of contemporary resin-based filling materials. METHODS: Specimens of Herculite (HE), Point 4 (P4), TetricCeram (TC), Miris (MI), TetricCeram HB (HB), Solitaire 2 (SO), SureFil (SU), Definite (DE), Admira (AD), Dyract AP (DY), Compoglass F (CO), and TetricFlow (TF) were prepared according to ISO 4049. Water sorption and solubility were measured after water storage at 37 degrees C for 7 days. RESULTS: Water sorption was HE 14 microg mm(-3), P4 17 microg mm(-3), TC 12 microg mm(-3), MI 13 microg mm(-3), HB 9 microg mm(-3), SO 18 microg mm(-3), SU 9 microg mm(-3), DE 14 microg mm(-3), AD 27 microg mm(-3), DY 19 microg mm(-3), CO 23 microg mm(-3), and TF 19 microg mm(-3). Solubility was HE 3 microg mm(-3), P4 3 microg mm(-3), TC 1 microg mm(-3), MI 0 microg mm(-3), HB 0 microg mm(-3), SO 3 microg mm(-3), SU 0 microg mm(-3), DE 1 microg mm(-3), AD 2 microg mm(-3), DY 4 microg mm(-3), CO -2 microg mm(-3), and TF 1 microg mm(-3). CONCLUSION: All materials met the corresponding requirement in ISO 4049. Filler load negatively correlated with water sorption but not with solubility. There was an influence of the resin matrix, too. No significant differences were found between composites, ormocers, and compomers.

Color stability of resin-based filling materials after aging when cured with plasma or halogen light.

The influence of curing devices and curing times on the color stability of filling resins was investigated by measuring the CIE-Laboratory-values after performing dry storage, water storage, and a Suntest (EN ISO 7491). Eight samples each of Charisma (CH), Durafill (DU), Definite (DE), and Dyract AP (DY) were light cured by using Translux Energy (TE) for 20, 40 or 60 s, or by using Apollo 95E (AP) for 3, 10 or 20 s. Minor color changes occurred for all dry stored materials, devices and curing times. The TE-cured, water-stored samples behaved similarly to the dry-stored ones, but the samples cured with AP revealed very strong color changes, mainly because of a drastic bleaching process. The bleaching of DU was significantly less than that of the other materials, but a strong white shift occurred. CH, DE, and DU showed very little (and even acceptable) discolorations after the Suntest when TE-cured. DY showed a drastically discoloration. All samples cured using AP drastically bleached and shifted to white for DU and DY but to dark for DE. In conclusion, the extent of discoloration depends on (i) the material, (ii) the test method, (iii) curing time, and (iv) the curing device. The halogen light-cured samples performed best.

Color stability of resin matrix restorative materials as a function of the method of light activation.

The purpose was to investigate the influence of curing devices and curing times on the yellow value (b-value) of composites, ormocers and compomers after performing a suntest (EN ISO 7491). Eight samples of Charisma (CH), Durafill (DU), Definite (DE), and Dyract AP (DY) each were light cured with Translux Energy (tungsten halogen light) for 20, 40 or 60 s and with Apollo 95-E (plasma light) for 3, 10 or 20 s. All samples were subjected to a suntest. Before and after the suntest the yellow values (b-values) were determined and the change (Delta b) was calculated. When cured with Translux Energy for 20 and 40 s DU, CH, and DY revealed significantly negative Delta b-values. The b-value of DE remained nearly constant. When cured for 60 s, DU and DE shifted to more yellow while CH and DY still bleached a little. When cured with Apollo 95-E, a dramatic bleaching process of all materials investigated occurred after the suntest (significant negative Delta b). It may be concluded that the bleaching of composites, ormocers and compomers depends on (i) the used light curing device and (ii) the chosen curing times. The tungsten halogen light provided highly significantly superior results.

Resin/Resin bonding: a new adhesive technology.

PURPOSE: Evaluation of a new surface treatment method to obtain a good bond strength between a luting composite and (1) a light-cured, (2) a heat-cured and (3) a thermoplastic resin. MATERIALS AND METHODS: Specimens were prepared and tests conducted according to ISO 10477, Amend. 1. The surfaces of Targis (light cured), SR Isosit (heat cured), and Dental D (thermoplastic) were ground under water cooling with 400-grit grinding paper, polished with 800-grit paper and air dried. Each resin material was divided into 3 groups of 10 specimens each. Group 1 was flame treated with a PyrosilPen for 5 s/2 cm2, group 2 for 10 s/2 cm2, and group 3 for 20 s/2 cm2. Subsequently, a methacryl silane was applied, followed by a luting composite. Prior to measuring shear bond strength, the specimens were thermocycled 5000 times in a water bath between 5 degrees C and 55 degrees C. SEM, FTIR investigations, and fracture analysis were also done. Etched and silanized Empress II - the gold standard - was used as a control. RESULTS: The following shear bond strengths were found: treatment time 5 s/2 cm2, Targis 25 (+/- 12) MPa, SR Isosit 17 (+/- 11) MPa; treatment time 10 s/2 cm2, Targis 23 (+/- 12) MPa, SR Isosit 26 (+/- 8) MPa; treatment time 20 s/2 cm2, Targis 29 (+/- 5) MPa, SR Isosit 26 (+/- 9) MPa. All Dental D specimens failed completely so that shear bond strength could not be measured. The control achieved 27 (+/- 6) MPa. No significant differences were found between the materials or the flaming times. On all flamed surfaces, Si was detected by FTIR. SEM showed that no heat destruction occurred at a flaming time of 5 s/2 cm2, a slight change at 10 s/2 cm2, and a significant change at 20 s/2 cm2. CONCLUSION: This new bonding technology is an effective method for surface-treating polymerized composite resin materials to obtain good bonding to luting composites. The method fails on thermoplastic resins.