Cement Film Thickness Research Articles

Influence of the Cement Film Thickness on the Push-Out Bond Strength of Glass Fiber Posts Cemented in Human Root Canals.

The present study evaluated the influence of the cement film thickness on the push-out bond strength of glass fiber posts in the cervical, medium, and apical thirds of root canal spaces. Thirty roots were randomly divided into three groups, according to the fiber post system's drills: (G1) #2; (G2) #3; (G3) #4. The posts were cemented using a self-adhesive cement, and a small amount of powdered Rhodamine B was used as a stain. Images of both sides of each slice were obtained before and after the push-out test. To determine the cement thickness, a macro routine was developed using the software KS 400. The data were analyzed statistically using Kruskal-Wallis and Dunn's test. G2 (14.62 ± 5.15 MPa) showed statistically higher bond strength values than G1 (10.04 ± 5.13 MPa) and G3 (7.68 ± 6.14 MPa). All groups presented higher bond strength values in the apical third. The bur diameter significantly influenced the results of the shear bond strength for the push-out test. The slight increase in the cement thickness allowed an increase in the values of shear bond strength when compared to very thin or very thick cement films.

Fracture Resistance of Lithium Disilicate Ceramics Bonded to Enamel or Dentin Using Different Resin Cement Types and Film Thicknesses.

To investigate the influence of cement film thickness, cement type, and substrate (enamel or dentin) on ceramic fracture resistance. One hundred extracted human third molars were polished to obtain 50 enamel and 50 dentin specimens. The specimens were cemented to 1-mm-thick lithium disilicate ceramic plates with different cement film thicknesses (100 and 300 μm) using metal strips as spacers. The cements used were etch-and-rinse (RelyX Ultimate) and self-adhesive (RelyX U200) resin cements. Compressive load was applied on the ceramic plates using a universal testing machine, and fracture loads were recorded in Newtons (N). Statistical analysis was performed by multiple regression (p < 0.05). Representative specimens were evaluated by scanning electron microscopy to control the cement film thickness. The RelyX Ultimate group with a cement thickness of 100 μm cemented to enamel showed the highest mean fracture load (MFL; 1591 ± 172.59 N). The RelyX Ultimate groups MFLs were significantly higher than the corresponding RelyX U200 groups (p < 0.05), and thinner film cement demonstrated a higher MFL than thicker films (p < 0.05). Bonding to dentin resulted in lower MFL than with enamel (p < 0.001). Higher fracture loads were related to thinner cement film thickness and RelyX Ultimate resin cement. Bonding to dentin resulted in lower fracture loads than bonding to enamel. Reduced resin film thickness could reduce lithium disilicate restoration fracture. Etch-and-rinse resin cements are recommended for cementing on either enamel or dentin, compared with self-adhesive resin cement, for improved fracture resistance.

In Vitro Fit and Cementation Resistance of Provisional Crowns for Single Implant-Supported Restorations.

This study aimed to verify marginal fit and the effect of cement film thickness standardization on retention of provisional crowns made with prefabricated acrylic cylinders on abutments, using two temporary luting agents subjected or not to mechanical cycling. Provisional crowns were made from bis-acryl (Luxatemp Fluorescence) or methyl methacrylate (Duralay) resins on acrylic cylinders and marginal fit and cement film thickness were evaluated. For retention evaluation, crowns were cemented with two temporary luting agents: non-eugenol zinc oxide (Tempbond NE) or calcium hydroxide-based (Hydcal) cements and subjected to tensile strength in a universal testing machine. After cleaning, debonded crowns were cemented again, subjected to mechanical cycling and retention was reassessed. The results of marginal fit and cement film thickness were analyzed by Student's t-test while retention of cements before and after mechanical cycling was analyzed using a mixed linear model. Methyl methacrylate crowns presented greater marginal misfit (p=0.001) and occlusal cement film thickness (p=0.003) than the bis-acryl ones. No difference was observed at axial cement film thickness (p=0.606). Resins (p=0.281) did not affect crown retention, but luting agents (p=0.029) and mechanical cycling (p=0.027) showed significant effects. The only significant interaction was mechanical cycling*luting agents, which means that luting agents were differently affected by mechanical cycling (p=0.002). In conclusion, the results showed that bis-acryl resin associated to calcium-hydroxide luting agent provided the best retention and lower cement thickness.

Can cement film thickness influence bond strength and fracture resistance of fiber reinforced composite posts?

This study compared the influence of cement film thickness (CFT) on bond strength (BS) and fracture resistance (FR) of fiber-reinforced composite (FRC) posts to root canal. One hundred bovine incisors were used for BS and FR analysis (n = 10) and distributed into five experimental groups according to FRC post diameters (WhitePost DC no. 0.5, no. 1, no. 2, no. 3, no. 4), leading to five different CFTs. The canals were prepared using drill no. 4 provided by the post manufacturer and irrigated with 2.5% NaOCl. After conditioning (24% H2O2/5 min) and silanization, posts were cemented with resin cement. BS was evaluated using push-out test and FR using the compression test at 45°. A stereomicroscope was used to measure CFT and to analyze failure pattern. BS data were subjected to two-way ANOVA and Scheffé test for contrast (α = 0.05); FR data were subjected to one-way ANOVA. BS was significantly affected by CFT, as the most well-adapted post achieved the highest values (p < 0.05). BS was similar for all root thirds. CFT did not affect fracture resistance. No root fractures were observed. A FRC post well adapted to the root canal results in higher BS values. Different CFTs did not influence the FR of teeth restored with FRC posts. The results indicate that post retention is improved when a well-adapted post is used, although this has not been critical to fracture resistance.

Retention of Root Canal Posts: Effect of Cement Film Thickness, Luting Cement, and Post Pretreatment.

The aim of this study was to investigate the effect of the cement film thickness of a zinc phosphate or a resin cement on retention of untreated and pretreated root canal posts. Prefabricated zirconia posts (CosmoPost: 1.4 mm) and two types of luting cements (a zinc phosphate cement [DeTrey Zinc] and a self-etch adhesive resin cement [Panavia F2.0]) were used. After removal of the crowns of 360 extracted premolars, canines, or incisors, the root canals were prepared with a parallel-sided drill system to three different final diameters. Half the posts did not receive any pretreatment. The other half received tribochemical silicate coating according to the manufacturer's instructions. Posts were then luted in the prepared root canals (n=30 per group). Following water storage at 37°C for seven days, retention of the posts was determined by the pull-out method. Irrespective of the luting cement, pretreatment with tribochemical silicate coating significantly increased retention of the posts. Increased cement film thickness resulted in decreased retention of untreated posts and of pretreated posts luted with zinc phosphate cement. Increased cement film thickness had no influence on retention of pretreated posts luted with resin cement. Thus, retention of the posts was influenced by the type of luting cement, by the cement film thickness, and by the post pretreatment.

Effect of working time on the film thickness of dental resin cements

Purpose: The aim of this study was to compare the film thicknesses of several resin cements as a function of time after mixing and to examine the effect of working time on the film thicknesses. Materials and methods: The film thickness (㎛) of 4 resin cements (n=10), 1 composite resin (Panavia F 2.0), 3 self-adhesive resin (Clearfil SA luting, Zirconite, RelyX U200) cements was measured at 20-second intervals after mixing of the cements up to 200 seconds under a load of 50 N. Linear regression was fitted to verify the effect of working time on the film thickness of each cement. Data were compared to the working time recommended by manufacturers using Wilcoxon test (α =.05). Results: All of the materials showed a positive linear correlation between the film thickness and working time. There was no statistically significant difference between the working time based on our results and the values recommended by the manufacturers even though there was a discrepancy between those two values. Conclusion: The film thickness of resin cements could increase with the increase of working time. Working time to meet the ISO standard of 50-㎛ maximum film thickness could be different from the manufacturer’ s recommended value. (J Korean Acad Prosthodont 2015;53:325-9)

Clinical marginal and internal adaptation of CAD/CAM milling, laser sintering, and cast metal ceramic crowns

Metal ceramic crowns are widely used in clinical practice, but comparisons of the clinical adaptation of restorations made with different processing techniques are lacking. The purpose of this study was to compare the clinical marginal and internal adaptation of metal ceramic crowns fabricated with 3 different techniques: computer-aided design and computer-aided manufacturing (CAD/CAM) milling (CCM), direct metal laser sintering (DMLS), and traditional casting (TC). Twenty CCM, 20 DMLS, and 20 TC metal ceramic crowns were fabricated for 42 patients. Before luting the crowns, silicone replicas were obtained to measure marginal gap and internal adaptation that was evaluated at 3 regions: axial wall, axio-occlusal angle, and occlusal surface. Measurements were made with a reflected light binocular stereomicroscope at 20× magnification and analyzed with 1-way analysis of variance (ANOVA) and the Bonferroni post hoc test (α=.05). The mean marginal gap values were 86.64 μm for CCM, 96.23 μm for DMLS, and 75.92 μm for TC. The means at the axial wall region were 117.5 μm for the CCM group, 139.02 μm for the DMLS group, and 121.38 μm for the TC group. One-way ANOVA revealed no statistically significant differences among the groups for measurements at the marginal gap (P=.082) and the axial wall region (P=.114). The means at the axio-occlusal region were 142.1 μm for CCM, 188.12 μm for DMLS, and 140.63 μm for TC, and those at the occlusal surface region were 265.73 μm for CCM, 290.39 μm for DMLS, and 201.09 μm for TC. The mean values of group DMLS were significantly higher at the axio-occlusal region and the occlusal surface region than those of other groups (P<.05). CCM, DMLS and TC metal ceramic crowns performed similarly in terms of clinical marginal and axial wall adaptation. The cement film thickness at the occlusal region and axio-occlusal region were higher for DMLS crowns.

In vitro evaluation of the film thickness of self-etching resin cements.

The aim of this study was to evaluate the film thickness of selfetching resin cement. The following materials were used: Group1, Relyx U100 (3M /ESPE); Group 2, BisCem (Bisco); Group 3, Max Cem (Kerr); Group 4, Set (SDI) and Group 5, Relyx ARC (3M/ESPE) as control. Two 5.4 x 76.2 x 1 mm glass slides were marked in the center to identify the area where the material would be placed. A volume of 0.05 ml was used for each specimen material. After 1, 3 and 6 minutes, a 50 N load was applied for one minute. The thickness of each specimen was then measured using a digital micrometer to the nearest 1 μm; (Digimatic, Mitutoyo Corporation, Japan.). Data were analyzed using ANOVA and Bonferroni's multiple comparison tests. No significant difference was found between the materials tested (p = 0.0921) or material/time interaction (p = 0.0864), but there were differences in the time factor (p = 0.0001). At one minute, the thinnest film was Relyx ARC (control) (14 μm), followed by Relyx U100 (17 μm), and Maxcem and SeT (19 μm). At 3 minutes, Group 5 (control) was also the thinnest film (19 μm), followed by Group 1 (21 μm), Group 3 (25 μm), Group 2 (29 μm), and Group 4 (31 μm). At 6 minutes, Group 4 was the thinnest (34 μm), followed by Group 1 (38 μm), Group 5 (40 μm), Group 2 (41 μm) and Group 3 (42 μm). The film thickness of resin cements was influenced by time and polymerization reaction. The film thickness of self-etching cements was low.

Influence of Cement Film Thickness on the Retention of Implant‐Retained Crowns

The main goal of this study was to establish a new, high precision procedure to evaluate the influence of cement film thickness on the retention of cemented implant-retained crowns. Ninety-six tapered titanium abutments (6° taper, 4.3 mm diameter, Camlog) were shortened to 4 mm. Computer-aided design was used to design the crowns, and selective laser sintering, using a cobalt-chromium alloy, was used to produce the crowns. This method used a focused high-energy laser beam to fuse a localized region of metal powder to build up the crowns gradually. Before cementing, preset cement film thicknesses of 15, 50, 80, or 110 μm were established. Glass ionomer, polycarboxylate, or resin cements were used for cementation. After 3 days storage in demineralized water, the retention of the crowns was measured in tension using a universal testing machine. The cement film thicknesses could be achieved with a high level of precision. Interactions between the factors cement and cement film thickness could be found (p ≤ 0.001). For all cements, crown retention decreased significantly between a cement film thickness of 15 and 50 μm (p ≤ 0.001). At 15 μm cement film thickness, the resin cement was the most retentive cement, followed by the polycarboxylate and then the glass ionomer cement (p ≤ 0.05). The results suggest that cement film thickness has an influence on the retentive strength of cemented implant-retained crowns.

An in vitro Comparison of Marginal Accuracy in Temporary Crowns

ABSTRACTPurposeTo compare the marginal accuracy of temporary crownsin vitro, using two autopolymerizing temporary crown materials.Materials and MethodsPolyethyl methacrylate and bis-acryl composite were used to make 15 temporary crowns each, on an ivorine mandibular first molar, prepared as to receive a porcelain-fused-to-metal (PFM) crown. Matrices were made of polyvinyl siloxane impressions of a lower typodont arch. After crowns were fabricated, margins of the crowns were trimmed under magnification. Afterwards, margins of prepared tooth and crowns were marked. Each tooth-crown assembly was then observed under microscope (4×). With digital images of each surface, gap between margins of crown and preparation margin was measured in millimeters using computer software, after calibration. Two examiners made the measurements. Independent samples t-test and one-way ANOVA with Bonferroni post hoc analysis were applied to determine the mean marginal gap.ResultsBis-acryl composite crowns exhibited 0.2 mm (SD ± 0.11) mean gap with greatest discrepancy at buccal margins. Mean gap with polyethyl methacrylate crowns was 0.3 mm (SD ± 0.17) with buccal and mesial margins exhibiting the greatest marginal discrepancy, at α &lt;0.001.ConclusionBoth materials did not exhibit ideal marginal accuracy, but temporary luting cement film thickness would compensate for the gap observed in the margins of bis-acryl composite crowns.How to cite this articleAdnan S, Khan FR, Umer F. Anin vitroComparison of Marginal Accuracy in Temporary Crowns. J Contemp Dent 2013;3(3):121-126.

Internal adaptation, marginal accuracy and microleakage of a pressable versus a machinable ceramic laminate veneers

ObjectivesThe aim of this study was to evaluate the internal adaptation and marginal properties of ceramic laminate veneers fabricated using pressable and machinable CAD/CAM techniques. Materials and methods40 ceramic laminate veneers were fabricated by either milling ceramic blocks using a CAD/CAM system (group 1 n=20) or press-on veneering using lost wax technique (group 2 n=20). The veneers were acid etched using hydrofluoric acid, silanated, and cemented on their corresponding prepared teeth. All specimens were stored under water (37°C) for 60days, then received thermocycling (15,000 cycles between 5 and 55°C and dwell time of 90s) followed by cyclic loading (100,000 cycles between 50 and 100N) before immersion in basic fuchsine dye for 24h. Half of the specimens in each group were sectioned in labio-lingual direction and the rest were horizontally sectioned using precision cutting machine (n=10). Dye penetration, internal cement film thickness, and vertical and horizontal marginal gaps at the incisal and cervical regions were measured (α=0.05). ResultsPressable ceramic veneers demonstrated significantly lower (F=8.916, P<0.005) vertical and horizontal marginal gaps at the cervical and incisal margins and lower cement film thickness (F=50.921, P<0.001) compared to machinable ceramic veneers. The inferior marginal properties of machinable ceramic veneers were associated with significantly higher microleakage values. ConclusionsPressable ceramic laminate veneers produced higher marginal adaptation, homogenous and thinner cement film thickness, and improved resistance to microleakage compared to machinable ceramic veneers. Clinical significanceThe manufacturing process influences internal and marginal fit of ceramic veneers. Therefore, dentist and laboratory technicians should choose a manufacturing process with careful consideration.

In in-vitro evaluation of effect of different finish lines on marginal adaptation in metal-ceramic restorations under thermo-mechanical loading

The aim of this study was to evaluate the marginal gap in terms of cement film thickness associated with shoulder, shoulder with 45° bevel, shoulder with 30° bevel and chamfer, under thermo-mechanical loading. Forty human mandibular molars were prepared and restored with ceramo-metal crowns. Teeth were thermo-mechanically loaded and vertically sectioned to evaluate the cement film thickness. Shoulder with 45° bevel provided the least marginal gap as compared with all the tested finish lines.

The fit of cobalt–chromium three-unit fixed dental prostheses fabricated with four different techniques: A comparative in vitro study

Objectives This study sought to evaluate and compare the marginal and internal fit in vitro of three-unit FDPs in Co–Cr made using four fabrication techniques, and to conclude in which area the largest misfit is present. Methods An epoxy resin master model was produced. The impression was first made with silicone, and master and working models were then produced. A total of 32 three-unit Co–Cr FDPs were fabricated with four different production techniques: conventional lost-wax method (LW), milled wax with lost-wax method (MW), milled Co–Cr (MC), and direct laser metal sintering (DLMS). Each of the four groups consisted of eight FDPs (test groups). The FDPs were cemented on their cast and standardised-sectioned. The cement film thickness of the marginal and internal gaps was measured in a stereomicroscope, digital photos were taken at 12× magnification and then analyzed using measurement software. Statistical analyses were performed with one-way ANOVA and Tukey's test. Results Best fit based on the means (SDs) in μm for all measurement points was in the DLMS group 84 (60) followed by MW 117 (89), LW 133 (89) and MC 166 (135). Significant differences were present between MC and DLMS ( p < 0.05). The regression analyses presented differences within the parameters: production technique, tooth size, position and measurement point ( p < 0.05). Significance Best fit was found in the DLMS group followed by MW, LW and MC. In all four groups, best fit in both abutments was along the axial walls and in the deepest part of the chamfer preparation. The greatest misfit was present occlusally in all specimens.

Effect of film thickness of resin cement on indirect restoration

Effect of film thickness of resin cement on indirect restoration

Water film thickness, flowability and rheology of cement–sand mortar

It is well known that the fresh properties of cement paste and cement–sand mortar are governed mainly by three parameters: water content, packing density and solid surface area. However, these parameters vary simultaneously upon any change in the mix composition and hence the evaluation of their individual and combined effects has been a difficult task. Recently, the authors have found that the effects of these parameters on the flowability and rheological properties of cement paste may be evaluated in terms of the water film thickness (WFT) of the solid–water mixture. Herein, this concept of WFT is extended to cement–sand mortar made of sand with a maximum size of 1·18 mm. A number of mortar samples proportioned with different water contents and different sand gradings were produced for packing density, flowability and rheological properties measurements. From the results, the WFT of each sample was determined and the effects of the WFT on the flowability and rheological properties of the mortar were investigated. The good correlations between the flowability and rheological properties with the WFT revealed that the concept of WFT is applicable also to cement–sand mortar.

Effect of film thickness of resin cement on bonding efficiency in indirect composite restoration

The purpose of this study was to evaluate the effect of film thickness of various resin cements on bonding efficiency in indirect composite restoration by measurement of microtensile bond strength, polymerization shrinkage, flexural strength and modulus, fractographic FE-SEM analysis. Experimental groups were divided according to film thickness (-control, -T50, -T100, -T150) using composite- based resin cements (Variolink II, Duo-Link) and adhesive-based resin cements (Panavia F, Rely X Unicem). The data was analyzed using ANOVA and Duncan's multiple comparison test (p 0.05). 2. Microtensile bond strength of composite-based resin cements were decreased significantly according to increasing film thickness (p 0.05). 3. Panavia F showed significantly lower polymerization shrinkage than other resin cements (p

In vitro analysis of the cement film thickness of two endodontic sealers in the apical region

The objective of the present study was to evaluate in vitro film thickness of two endodontic sealers containing epoxy-resin and zinc-oxide-eugenol, respectively in the apical region of the root canal system. A total of 20 palatine roots of the first maxillary molars were submitted to instrumentation up to a #40 file by the step-back technique and irrigated with 2 ml of NaOCl after each change of file. The roots were divided at random into two groups of 10 elements; one group was sealed with the Sealer 26 cement and the other one with the EndoFill cement using the classical technique. The roots were abraded in the apical region until exposure of the filling and cut crosswise at 3 mm to obtain samples. The samples were analyzed by optic microscopy with 40X magnification. The images obtained were recorded using the Adobe Premiere 5.1 software and submitted to morphometric analysis using an integration grid that permitted the quantification of the area filled with the sealer or gutta-percha, and eventual empty spaces. Statistical analysis of the data (Kruskal-Wallis test, P < 0.05) revealed no significant differences between the epoxy-resin-based cement Sealer 26 (47.85%) and the zinc- oxide- eugenol-based cement EndoFill (54.16%). We conclude that the two sealers tested showed a similar behavior regarding the cement film thickness in the apical region.

The effect of resin cement film thickness on the pullout strength of a fiber-reinforced post system

Debonding is a common cause of failure encountered with fiber posts and usually occurs along the post space-dentin adhesive interface. The ideal thickness of the resin cement needed to improve retentive bond strength is unknown. The purpose of this study was to evaluate the effect of 4 different post-space diameters and related resin cement film thicknesses on the bond strength between fiber posts and root dentin. Eighty human maxillary central incisors with similar root lengths were selected, sectioned at the cemento-enamel junction, and the roots were treated endodontically. The roots were divided into 4 groups (n=20), and the post spaces were prepared to a depth of 8 mm using 1 of 4 different drills with a different diameter: Torpan drill ISO 90 for the control group (D90); and Torpan Drill ISO 100 (D100), Torpan Drill ISO 120 (D120), or Enapost Drill ISO 140 (D140) for the 3 test groups. Quartz fiber posts (Endo Lightpost), 0.9 mm in apical diameter, were luted (Panavia 21) in each specimen after dentin bonding procedures. The specimens were then subjected to a pullout test using a universal testing machine at a crosshead speed of 1.0 mm/min, and the maximum force required to dislodge each post was recorded (N). Data were analyzed using 1-way ANOVA and Tukey multiple comparisons tests (a=.05). The mean bond strength values (SD) in N for the experimental groups D100 (181.7 (55.3)) and D120 (210.7 (55.0)) were higher (P=.036 and <.001, respectively) than that obtained for the D90 control group (138.5 (49.2)). The lowest mean value was recorded for the D140 group (91.1 (36.0)). All experimental groups showed significantly different results, when compared to the control group. A multiple comparison between experimental groups showed significant differences (P<.001). Only the comparison between D100 versus D120 was not significant. Data suggest that the resin cement film thickness influences the pullout strengths of fiber-reinforced posts. For the selected quartz fiber-reinforced post and resin luting cement, the highest bond strength values were not obtained when the thinnest cement layer was tested (D90) but when oversized post spaces were used (D100-D120). However, when the cement film thickness was too great (D140), the dislocation resistance of fiber-reinforced posts was significantly decreased.

Effect of Resin Luting Film Thickness on Fracture Resistance of a Ceramic Cemented to Dentin

The aim of this study was to evaluate the fracture resistance of ceramic plates cemented to dentin as a function of the resin cement film thickness. Ceramic plates (1 and 2 mm thicknesses) were cemented to bovine dentin using resin composite cement. The film thicknesses used were approximately 100, 200, and 300 microm. Noncemented ceramic plates were used as control. Fracture loads (N) were obtained by compressing a steel indenter in the center of the ceramic plates. ANOVA and Tukey tests (alpha= 0.05) were used for each ceramic thickness to compare fracture loads among resin cement films used. Mean fracture load (N) for 1-mm ceramic plates were: control-26 (7); 100 microm-743 (150); 200 microm-865 (105); 300 microm-982 (226). Test groups were significantly different from the control group; there was a statistical difference in fracture load between groups with 100 and 300 microm film thicknesses ( p < 0.01). Mean fracture load for 2-mm ceramic plates were: control-214 (111); 100 microm-1096 (341); 200 microm-1067 (226); 300 microm-1351 (269). Tested groups were also significantly different from the control group ( p < 0.01). No statistical difference was shown among different film thicknesses. Unluted specimens presented significantly lower fracture resistance than luted specimens. Higher cement film thickness resulted in increased fracture resistance for the 1-mm ceramic plates. Film thickness did not influence the fracture resistance of 2-mm porcelain plates.

The Effects of Hydroxyapatite on Bonding Strength between Dental Luting Cement and Human Teeth

This study aimed to investigate the effects of hydroxyapatite on bonding strength between dental luting cement and human teeth. In the previous study, bonelike forming ability by mixing hydroxyapatite with several bone cements was reported in a protein-free acellular simulated body fluid with ion concentrations nearly equal to those of the human blood plasma. Therefore in this experiment, we assumed that if bonelike apatite layer could form between dental luting cement and human teeth, the bonding strength between the two would improve. In addition, we expected the HA mixed dental luting cement to improve the physical properties. Fuji I glass ionomer and Relyx™ glass ionomer cement were the selected dental luting cements and the film thickness, setting time and compressive strength were measured mixing various concentrations of hydroxyapatite. Glass ionomer cement with the most superior physical properties(Fuji I ; 20% hydroxyapatite, Relyx™ ; 15% hydroxyapatite) was immersed in the simulated body fluid for three weeks and the surface was observed under SEM after measuring the bonding strength. As the concentration of HA increased, the film thickness of hydroxyapatite-glass ionomer cement decreased, the setting time increased, and the compressive strength increased. The most noteworthy results were that bonding strength increased, and that bonelike apatite formed on the tooth surface when observed under SEM.