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PubMed2004

Restoration materials for primary molars-results from a European survey.

OBJECTIVE: The aim of this study was to obtain an overview of the materials and restorative techniques taught for Class I and Class II restorations in primary molars of different European departments for paediatric dentistry and to compare the results to those for North America. METHODS: The forms were sent to the chairmen of the departments of paediatric dentistry or-when included into the department for operative dentistry-to the director of 200 universities in 32 European Countries. The questions concerned the preferred materials and techniques, as well as the indications or contraindications for the use of the different tooth coloured materials. RESULTS: Forty-three percent of the universities from western European countries (excluding Germany) responded to the survey. A 97% answer rate was obtained from German Schools. Of the other European regions, the response rate varied remarkably (24-54%). Also, opinions on materials used and methods applied were different from country to country. Only in a few regions (Eastern Europe), amalgam remains the filling material of first choice for Class I and II cavities in primary molars, whereas in others, the use has been restricted and tooth coloured materials, especially compomers or resin-modified glass ionomer cements, are being preferred. CONCLUSIONS: Great diversity in teaching was observed not only among the European countries, but also within the countries themselves which makes it difficult to compare the results of our study to the ones obtained from the US.

Compomers↗

PubMed2006

Nine-year evaluation of a polyacid-modified resin composite/resin composite open sandwich technique in Class II cavities.

OBJECTIVES: The aim of this study was to evaluate in an intraindividual comparison the durability of a polyacid-modified resin composite/resin composite open sandwich restoration in a 9 years follow-up. A polyacid-modified resin composite (PMRC; compomer, Dyract) was placed as an intermediate layer and covered with resin composite (RC, Prisma TPH). A direct RC restoration was used as control. METHODS: Each of 57 patients, received at least one pair of Class II restorations, one open sandwich and one resin composite control. In total 75 pairs of Class II restorations, 68 premolars and 82 molars, all in occlusion, were placed by two dentists. Most of the cavities were surrounded by enamel. The restorations were evaluated at baseline, 6, 12, 24, 36 months and 9 years by slightly modified USPHS criteria. Survival of restorations grouped on the two different techniques was determined using Kaplan-Meier survival curves. RESULTS: After 9 years, 14 of 135 evaluated restorations were estimated as unacceptable, 6 in the sandwich group and 8 in the control group. Over all annual failure rate during the 9-year period was 1.1%. The survival rate was not significant different between the two techniques (p=0.604). Reasons of failure were: secondary caries (8), fracture of tooth (1), fracture of restoration (2), endodontic treatment (3). CONCLUSIONS: Both restorative techniques showed good durability during the 9-year period. No clinical advantage was observed for the sandwich technique.

Adolescent↗

PubMed2004

The effect of airborne-particle abrasion on the shear bond strength of four restorative materials to enamel and dentin.

STATEMENT OF PROBLEM: The role of airborne-particle abrasion on the bond strength of restorative materials to enamel and dentin is controversial. PURPOSE: The purpose of this study was to evaluate the effect of airborne-particle abrasion on the shear bond strengths of 4 restorative materials to enamel and dentin. MATERIAL AND METHODS: One hundred twelve extracted human maxillary anterior teeth were divided into 2 groups of 56 teeth each. In the first group flat enamel surfaces were prepared, and in the second flat dentin surfaces were prepared. Half the teeth in each group (n=28) were airborne-particle abraded. The remaining 28 teeth in each group were prepared with silicone carbide paper (control). Specimens in both groups were divided into 4 subgroups (n=7). A composite, a compomer, a resin-modified glass ionomer cement, and a conventional glass ionomer cement were applied to enamel and dentin surfaces (3 mm diameter and 4 mm height). After 24 hours of storage in water, specimens were subjected to shear forces in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Shear bond strength data (MPa) were analyzed with 3-way ANOVA and Tukey HSD tests (alpha=.05). RESULTS: Airborne-particle-abraded specimens showed significantly higher shear bond strengths than control specimens. The 2-way interaction between tooth structure and restorative materials was significant. CONCLUSION: The use of airborne-particle abrasion increased the shear bond strength of restorative materials tested to enamel and dentin.

Air Abrasion, Dental↗

PubMed2001

Sealing and dentin bond strength of adhesive systems in selected areas of perfused teeth.

OBJECTIVES: (1) Test the sealing capacity and tensile strength of various adhesive systems: Scotch Bond 1 (Single Bond in USA)(SB1)+Z100, Syntac Sprint (SYN)+Tetric Ceram, Prime and Bond 2.1 (PB21)+TPH Spectrum, F2000 (Adhesive+Compomer) (F2000) and Optibond Solo (OPT)+Prodigy, to perfused teeth (30 cm distilled H2O), in select areas. (2) Determine the relationship between sealing ability and size of adhesive area (BA) with tensile strength (TS). METHODS: Segments of human third molars (n=67) sealed with amalgam on their coronal side were connected to a perfusion system (30 cm distilled H2O), to measure the basal permeability. Access cavities were drilled through the amalgam to expose dentin (area range: 8.7-20.8 mm2) and measure the permeability of that area. Cavities were sealed with one of the test materials and permeability measured prior to tensile testing. The percentage of decrease in permeability (PPD) that occurred with the different combinations of materials was also measured. RESULTS. TENSILE STRENGTH: there were no statistically significant differences among groups. PERMEABILITY: ANOVA showed that there were statistically significant differences in the mean % decrease in permeability (PPD) among groups (p=0.018). Student-Newman-Keuls test (p<0.05) detected that the mean PPD of F2000 ranked statistically higher than that of SB1. Relationship among variables: a linear correlation was found defined by the formula TS=7.47+0.008 x PPD-0.23 x BA, with a significance of the model p=0.0097. SIGNIFICANCE: None of the materials studied reduced permeability up to 100%. They all produced low tensile bond strengths (maximum mean value of groups: 5.51 MPa (OPT)).

Acetone↗

PubMed2003

The recharge of esthetic dental restorative materials with fluoride in vitro-two years' results.

OBJECTIVES: A range of esthetic restorative dental materials are now available to dental clinicians. The aim of this study was to evaluate the relative fluoride recharge potential of a number of these materials in vitro over two years. METHODS: Disc samples (12 mm x 2 mm) of each of the materials were placed into artificial saliva at neutral pH. The materials tested were: two glass ionomers (Chemfil; Ketac-Fil), two resin-modified glass ionomers (Photac-Fil Aplicap; Vitremer), two compomers (Dyract; Compoglass) and two composites (Heliomolar; Concise). At 13 intervals over a two years period the discs were subjected to a 2 min fluoride recharge by exposure to sodium fluoride (500 ppm F). The pre- and post-recharge fluoride release values were determined using an ion sensitive electrode. RESULTS: At all time intervals the post-recharge fluoride release of the materials was significantly different (MANOVA p<0.0001). The mean values for post-recharge fluoride release after two years were: Chemfil 10.3, Ketac 3.0, Vitremer 9.0, Photac-Fil Aplicap 12.1, Compoglass 5.0, Dyract 3.6, Concise 0.3, Heliomolar 0.2 (units = microgF/cm(2)/h). SIGNIFICANCE: Esthetic fillings vary significantly in their capacity to absorb and re-release fluoride. The glass ionomer-based materials displayed a far greater potential for fluoride recharge than the composites, in which the recharge was virtually negligible. Whilst it cannot be assumed that fluoride release is directly proportional to cariostatic potential, these results suggest that, where possible, glass ionomer-based materials should be used in patients who have a high caries rate.

Analysis of Variance↗

PubMed2003

A comparative study of the properties of dental resin composites polymerized with plasma and halogen light.

OBJECTIVES: Newly developed curing units utilizing plasma arc methodology have been advocated for rapid curing of dental composites. This study was conducted to investigate the effect of plasma light using a 3 s and a step cure regime on the properties of four dental restorative materials and compare it with properties resulting from halogen light curing of the same materials. METHODS: Composites Quadrant, Filtek and two polyacid modified composites (compomers) Dyract AP and Compoglass F were cured, using a conventional halogen light, a plasma light for 3 s (Apollo95E) and a plasma step cure (Apollo 95E) method. The parameters studied for characterization of the restorative materials were polymerization exotherm, surface hardness and their interactions with saline. RESULTS: Irradiation with plasma light for 3 s or step cure produced an order of hardness: Filtek>Compoglass F>Dyract AP>Quadrant (p<0.001), however, halogen cure yielded an order of hardness: Filtek>Quadrant>Dyract AP>Compoglass F. No significant differences in hardness were observed on the exposed and non-exposed surfaces of the materials cured by plasma step cure whereas a 3 s cure yielded a significant difference in the cases of Quadrant, Compoglass F and Dyract AP (p<0.001). Mass losses were also found to be greater in the specimens cured by plasma light for 3 s in comparison with plasma step cure and halogen cure. SIGNIFICANCE: Plasma step and halogen curing were found to yield composites with superior properties in comparison to a 3 s plasma cure, suggesting, that a step cure regime is a preferred method, when a plasma light unit is used. A 3 s curing with a plasma light may lead to less than optimum properties of the composite cements.

Absorption↗

PubMed2004

Marginal adaptation in dentin of a self-adhesive universal resin cement compared with well-tried systems.

OBJECTIVES: This study compares the marginal adaptation of a new self-adhesive universal resin cement with only one application step, to the marginal adaptation of established cements and their corresponding adhesive systems. METHODS: All-ceramic crowns were inserted on human molars using a new self-adhesive universal resin cement without and with one pre-treatment step, a resin cement with a smear-layer removing and a compomer cement with a smear-layer dissolving adhesive system. After simulation of five years oral stress, the marginal adaptation was evaluated by dye penetration and scanning electronic microscope analysis using the replica technique. RESULTS: Scanning electron microscopy: all investigated luting agents showed comparable amounts of 'perfect margin' ranging between 88-98% (median). Dye penetration: the self-adhesive system had significantly lower dye penetration (18-25%, median). SIGNIFICANCE: The results indicate that a self-adhesive universal resin cement without pre-treatment can provide a marginal adaptation at dentin which is comparable to established luting agents.

Coloring Agents↗

PubMed1997

Comparison of surface roughness of oral hard materials to the threshold surface roughness for bacterial plaque retention: a review of the literature.

OBJECTIVES: The roughness of intraoral hard surfaces can influence bacterial plague retention. The present review evaluates the initial surface roughness of several intraoral hard materials, as well as changes in this surface roughness as a consequence of different treatment modalities. METHODS: Articles found through Medline searches were included in this review if they met the following criteria: 1) stated threshold surface roughness values and reputed change in surface roughness due to different manipulation techniques; or 2) included standardized surface conditions that could be compared to the treated surface. RESULTS: Recently, some in vivo studies suggested a threshold surface roughness for bacterial retention (Ra = 0.2 micron) below which no further reduction in bacterial accumulation could be expected. An increase in surface roughness above this threshold roughness, however, resulted in a simultaneous increase in plaque accumulation, thereby increasing the risk for both caries and periodontal inflammation. The initial surface roughness of different dental materials (e.g., teeth, abutments, gold, amalgam, acrylic resin, resin composite, glass ionomer or compomer and ceramics) and the effect of different treatment modalities (e.g., polishing, scaling, brushing, condensing, glazing or finishing) on this initial surface roughness were analyzed and compared to the threshold surface roughness of 0.2 micron. The microbiological effects of these treatment modalities, if reported, are also discussed and compared to recent in vivo data. SIGNIFICANCE: Based on this review, the range in surface roughness of different intraoral hard surfaces was found to be wide, and the impact of dental treatments on the surface roughness is material-dependent. Some clinical techniques result in a very smooth surface (compressing of composites against matrices), whereas others made the surface rather rough (application of hand instruments on gold). These findings indicated that every dental material needs its own treatment modality in order to obtain and maintain a surface as smooth as possible.

Acrylic Resins↗

PubMed2000

Interface dimensions of CEREC-2 MOD inlays.

OBJECTIVES: To quantify the width of the cement interface between ceramic inlays generated by the CEREC-2 CAD-CAM system and the tooth, and to determine the effect of cement viscosity on the interface width. METHODS: Standardised MOD cavities were cut in 15 human premolar teeth using a custom paralleling device. A ceramic inlay was made with a CEREC-2 CAD-CAM machine for each tooth. The inlays were cemented using one of three resin-based composite systems of varying viscosity; a hybrid microfilled posterior composite, a compomer restorative and a dual-cure luting composite. The teeth were subsequently sectioned and measurements were taken at 21 key points with the aid of an image-analysis light microscopy system. RESULTS: Statistical significance tests were applied to examine for difference in interface dimensions at specific points within each of the cement-groups and amongst groups. The interface space at the occlusal walls has a distinct wedge shape, being narrower at the external interface (50 microns, SD 15) than internally (211 microns, SD 38). There is no statistically significant difference in the interface dimensions of the gingival floor between the boxes that lie above and below the CEJ. There is no statistically significant difference in the width of the interface at any given point between the three cement groups. SIGNIFICANCE: There is a significant improvement in the fit of CEREC-2 restorations when compared with the original CEREC system. Cements of varying viscosity (within the measured range) may be used for cementation of these inlays, without adversely affecting the width of the interface. Caution must be exercised with light-activated composite cements to ensure adequate transmission of light through the ceramic and the underlying composite cement.

Bicuspid↗

PubMed2000

Dimensional changes of resin/ionomer restoratives in aqueous and neutral media.

OBJECTIVES: The aim was to study dimensional time-dependence of resin/ionomer formulations from 5 min age to one month and to separate out the intrinsic setting shrinkage and hygroscopic expansion effects, by using non-aqueous and aqueous storage media, respectively. METHODS: Materials studied included: A: resin-, B: metal- and C: polyphosphonate-modified glass-ionomer cements [GICs]; and controls of D: poly-acid modified composite [compomer]; and E: resin-composite. Separate specimen groups (n = 5) were stored in different storage-media: (i) silicone fluid; (ii) de-ionized water. Experiments were repeated at 23 and 37 degrees C. Volumetric changes of specimens (4 mm diameter x 6 mm height) were obtained via accurate mass measurements (to 10(-4) g), using Archimedes principle, with silicone or water also used as the Archimedean fluid. These measurements were made periodically over a 30 day period, post fabrication. RESULTS: In silicone at 23 degrees C, all materials underwent further gradual intrinsic shrinkage (after 5 min from mix). This was highly significant (p < 0.05) for the RM-GIC (A). At 37 degrees C, however the RM-GIC expanded, indicating that its cure is temperature-sensitive. In water, at 23 and 37 degrees C, the shrinkage was either partially offset (materials C, D, E), or replaced by appreciable expansions (materials A and B). Differences between RM-GIC (A) and MM-GIC (B) were significant (p < 0.05). SIGNIFICANCE: The deployment of dual storage media made an important contribution to the separate analysis of the volumetric changes due to the on-going setting chemistry in these systems and the time-dependent effects of an aqueous environment.

Analysis of Variance↗

PubMed2003

Short-term fluoride and cations release from polyacid-modified composites in a distilled water, and an acidic lactate buffer.

Fluoride and various cations release from three commercial compomers (Dyract, Dyract AP and Compoglass-F) and a resin-modified glass ionomer (Fuji-II LC) as a control were measured up to 7 days in distilled water and 0.01M lactate buffer solution with pH 4.1. The surface morphological change before and after the release experiment was observed with a scanning electron microscopy. Fluoride, aluminum and strontium ions were released from Dyract, Dyract AP and Fuji-II LC much more in the lactate buffer than in the distilled water. With compoglass-F containing barium instead of strontium, barium was released in the same way. X-ray diffraction analysis confirmed that fluoride release from Dyract and Dyract AP was derived mainly from SrF(2) contained in Dyract and Dyract AP. However, fluoride release from Compoglass-F was derived from glassy phase though it contained much fluoride as YbF(3). Cumulative release amount of each species versus square root of time plot showed good linearity, indicating that the dissolution was controlled by the diffusion mechanism. The surface characteristics of disks for each material, which were immersed in the lactate buffer, were quite different from the surface before and after immersion in deionized water, especially with Dyract. After immersion in the lactate buffer, many voids which were left after dissolution of the filler particle, were seen obviously on the surface of Dyract.

Aluminum↗

PubMed2000

Effect of cement type on retention of a tapered post with a self-cutting double thread.

OBJECTIVES: The aim of this in vitro study was to examine the effect of varying the cement type on the retention of a prefabricated tapered titanium post with a self-cutting double thread (Perma-tex activ). METHODS: A total of 130 suitable roots from extracted human permanent teeth were selected. Post holes were prepared using the instruments supplied with the post system. One-hundred-twenty posts (medium size) were luted with one of four luting agents: a zinc-phosphate cement (Harvard), a glass-ionomer cement (Ketac Cem), a compomer luting agent (Dyract Cem), and a new capsulated composite luting system (Compolute). The cement groups were subdivided into three treatment groups with 10 posts each: group 1 (4-week water storage at 37 degrees C), group 2 (4-week water storage at 37 degrees C, 4000 cycles 5-55 degrees C), group 3 (4-week water storage at 37 degrees C, 4000 cycles 5-55 degrees C, 3 x 4 min mechanical stress: 40N vibrations). Another 10 posts inserted without cement and stored like group 1 served as a control. Retention was measured on a universal testing machine (Zwick Z050/TH3A) with a crosshead speed of 0.1cm/min. Data were analyzed using ANOVA with a Bonferroni or Tamhane adjustment for multiple comparisons (significance level alpha=0.05). RESULTS: In group 1, Dyract Cem was significantly more retentive than the other three cements and the control group (no cement). In group 2, Compolute demonstrated significantly higher retention than Harvard and Ketac Cem. In group 3, Compolute, Dyract Cem, and Ketac Cem obtained higher retentive values than Harvard without differing from one another. Within the cement groups, thermocycling (group 2) caused a significant decrease in retention compared to group 1 only for Dyract Cem. All cements except Compolute were different from group 1 after a combination of thermocycling and mechanical stress (group 3). CONCLUSIONS: The retention of the tapered post with a self-cutting double thread was significantly influenced by the cement type used.

Analysis of Variance↗

PubMed1998

A comparison of fluoride release from various dental materials.

OBJECTIVE: The aim of this study was to determine, in vitro, the relative short- and long-term fluoride release from four resin-modified glass ionomers (Fuji II LC, Vitremer, Enforce & Advance), a polyacid-modified composite resin (Dyract compomer) and a bonding agent (OptiBond). METHODS: All the materials were prepared as outlined by the manufacturers. Circular discs of the materials mentioned were suspended in water for up to 300 days and the non-cumulative 24-h fluoride release was determined potentiometrically at chosen times. RESULTS: The amounts of fluoride released during the first day were Vitremer (1.46 micrograms mm-2), Advance (1.18 micrograms mm-2), Fuji (1.08 micrograms mm-2), Optibond (0.33 microgram mm-2), Dyract (0.31 microgram mm-2) and Enforce (0.15 microgram mm-2). After the second day the sequence changed slightly and remained approximately the same for the rest of the 300-day period. There was also an increase in the fluoride release during the 60-200-day period relative to the previous period. CONCLUSION: In general the most fluoride was released by Advance and not by Fuji II LC or Vitremer. For most materials, fluoride is still released after 300 days. Furthermore, even a thin layer of bonding agent released a relatively high amount of fluoride (volume-wise the most) at the beginning. It is deduced that even the release of relatively low amounts of fluoride may result in significant concentrations of fluoride in a microleakage gap.

Analysis of Variance↗

PubMed1998

The uptake and release of fluoride by ion-leaching cements after exposure to toothpaste.

OBJECTIVES: The cariostatic action associated with the glass-ionomer cement (GIC) is usually attributed to its sustained release of fluoride. However the ability of the GIC to act as a fluoride reservoir, taking it up from an external source (e.g. toothpaste, mouthwash) and subsequently releasing it over time, may also be a contributory factor. This study investigated the reservoir effect of various recently introduced ion-releasing cements: two resin-modified glass-ionomer cements (Fuji II LC, Vitremer), a compomer (acid-modified composite resin) (Dyract), and a recently introduced conventional glass-ionomer (Fuji IX). METHODS: Specimens were exposed to a fluoridated toothpaste after 28 and/or 58 days. The release of fluoride into the storage water, both before and after exposure, was monitored using a differential electrode cell. RESULTS: There was no significant difference in the fluoride releases from Vitremer and Fuji II LC. These materials released significantly more fluoride than Fuji IX and Dyract. All the materials released more fluoride on the day after exposure to an external fluoride source compared with the day before exposure. Release rates returned to baseline within 3 days. Within the time periods of the study, only the uptake/re-release of Fuji IX was adversely affected by late exposure. All the materials showed an enhanced uptake and release on repeated exposure to the external fluoride source. CONCLUSIONS: All the materials under test (Dyract, Fuji II LC, Vitremer and Fuji IX) released significant amounts of fluoride and reacted positively to exposure to an external fluoride source.

Cariostatic Agents↗

PubMed1999

Fluoride release from orthodontic bonding agents: a comparison of three in vitro models.

The aim of this in vitro study was to compare fluoride release from two cement disc models (partially varnished and unvarnished) of three orthodontic bonding materials with fluoride release from the same materials when used to bond an orthodontic bracket onto a tooth surface. A resin-modified glass ionomer cement (Vitremer) and a compomer material (Dyract Ortho) were compared with a conventional resin adhesive (Right-On). Ten discs (3.0 mm diameter and 1.5 mm thick) of each material were manufactured in a silicone mould and ten premolar teeth were bonded with orthodontic brackets using each material. All the premolar teeth were covered with nail varnish up to the bracket periphery and five of the discs for each material were coated with nail varnish on both upper and lower surfaces which halved the surface area. The fluoride released into 2 ml of deionised water, from each tooth or disc, was measured at regular intervals over 60 days. At 60 days, cumulative fluoride release was highest from the unvarnished discs, less for the varnished discs and least from the tooth-bracket model for both test materials. Despite having twice the surface area, the unvarnished disc model released only 1.2 to 1.5 times more fluoride than the varnished disc model. Compared with the tooth-bracket model, the unvarnished discs released 3.0 to 4.5 times more fluoride, whereas the varnished discs released only 2.2 to 3.7 times more fluoride. For the materials tested in this study, halving the surface of the discs did not reduce the cumulative fluoride release by half. The tooth/bracket model with minimal bonding material demonstrated substantial cumulative fluoride release. The pattern of fluoride release was similar for all models tested.

Analysis of Variance↗

PubMed1999

Crack formation of all-ceramic crowns dependent on different core build-up and luting materials.

OBJECTIVES: The aim of this in vitro study was to evaluate various core build-up and luting materials regarding their effect on crack formation of all-ceramic crowns. METHODS: Fifty-six freshly extracted sound human third molars were prepared according to a standardized procedure obtaining a circular shoulder of 1.5 mm with all margins located in dentin. Sixty percent of the dentin volume were removed and restored with totally bonded build-up composite resins or resin-modified glass ionomer cements (RMGIC) or compomers. Cast IPS-Empress caps were manufactured and luted with the different materials. For each material group, the volumes of the core build-ups and of the luting cements were determined. The caps were examined for cracks after 1, 3, 6, 9 and 12 months storage in 0.9% saline solution at 37 degrees C. RESULTS: The tested groups revealed no major differences in the percentage of the core build-ups and in the volume of the luting cements. After 12 months only the group with composite resin build-up and luting showed no crack formation. RMGIC/compomer build-up or RMGIC/compomer luting always resulted in cracking of the caps. CONCLUSIONS: Within the limits of this study it can be concluded that the hygroscopic expansion of RMGIC/compomer materials led to failure of all-ceramic crowns, when the materials are used for both core build-up or adhesive bonding.

Acrylates↗

PubMed1998

In vitro fluoride release from restorative materials in water versus artificial saliva medium (SAGF).

OBJECTIVES: An extensive number of investigations have focused in recent years on the process of fluoride release by glass-ionomer cements. In order to compare the fluoride release of two recent resin-modified glass-ionomer cements (RMGICs) and one compomer, we investigated the initial and subsequent fluoride release in distilled water and in a mineral medium with composition similar to saliva (SAGF), as well as the renewal effect of the media on the release. METHOD: A preliminary thermodynamic study defined conditions under which the measurements by fluoride-selective electrode potentiometry were not affected by the presence of Ca2+ ions in SAGF. Disk-shaped samples (5 mm x 3 mm) for each material were placed in 5 ml of distilled water (n = 12) or 5 ml of SAGF (n = 12) and fluoride released was measured after 1, 2 and 7 days. For the investigation of medium renewal effect, RMGIC sample were dipped into distilled water for 5 days. Subsequently 12 samples of each material were placed for 7 days into water or SAGF, with or without daily renewal of the medium before fluoride-release measurements. The elements present on the surface of the RMGICs were analyzed by scanning electron microscopy. RESULTS: RMGICs released significantly more fluoride in water than in artificial saliva. The presence of CaF2 at the interface accounts for this phenomenon. The thickness of the CaF2 layer depends on the speed of its initial formation and renewal of the testing medium. A pattern of CaF2 formation was proposed.

Calcium Fluoride↗

PubMed2003

Identification of organic eluates from four polymer-based dental filling materials.

Elution from polymer-based dental filling materials may have a potential impact on the biocompatibility of the materials. Since information from the manufacturers about ingredients in the materials often is incomplete, analyses of eluates from the materials are necessary for a better knowledge about possible harmful compounds. The aim of this study was to identify organic eluates from polymerized samples of two composites, one compomer and one resin-reinforced glass ionomer cement. Samples were immersed in ethanol or Ringer's solution. Organic leachables were analyzed by gas chromatography-mass spectrometry. Identification was confirmed with reference substances, if available. Among components detected were monomers, co-monomers, initiators, stabilizers, decomposition products and contaminants. Thirty-two substances were identified and 17 were confirmed with reference substances. From elution in Ringer's we identified 13 eluates from Tetric Ceram, 10 from Z250, 21 from Dyract and six from Fuji II LC; HEMA, HC and CQ were found in all samples. From elution in ethanol 12 eluates from Tetric Ceram, 18 eluates from Z250, 19 from Dyract and 10 from Fuji II LC were identified. The diversity of eluates from the four materials under study is demonstrated. Owing to variation between the materials, the biocompatibility including the allergenic potential may be different.

Chromatography, Gas↗