Radiopacity of composite dental materials using a digital X-ray system

Assessment of sealing efficacy, radiopacity, and surface topography of a bioinspired polymer for perforation repair

Background

Root perforation repair presents a significant challenge in dentistry due to inherent limitations of existing materials. This study explored the potential of a novel polydopamine-based composite as a root repair material by evaluating its sealing efficacy, radiopacity, and surface topography.

Methods

Confocal microscopy assessed sealing ability, comparing the polydopamine-based composite to the gold standard, mineral trioxide aggregate (MTA). Radiopacity was evaluated using the aluminium step wedge technique conforming to ISO standards. Surface roughness analysis utilized atomic force microscopy (AFM), while field emission scanning electron microscopy (FESEM) visualized morphology.

Results

The polydopamine-based composite exhibited significantly superior sealing efficacy compared to MTA (P < 0.001). Radiopacity reached 3 mm aluminium equivalent, exceeding minimum clinical requirements. AFM analysis revealed a smooth surface topography, and FESEM confirmed successful composite synthesis.

Conclusion

This study demonstrates promising properties of the polydopamine-based composite for root perforation repair, including superior sealing efficacy, clinically relevant radiopacity, and smooth surface topography. Further investigation is warranted to assess its clinical viability and potential translation to endodontic practice.

The radiographic evaluation of 11 different resin composites

Radiopacities of dental materials used in restorations are very important in making the radiographic diagnosis. Therefore, the aim of our study was to evaluate the radiopacity of five single-shade and six simplishade resin composites with digital technique. Five different single-shade (Charisma Topaz One, Omnichroma, Clearfil Majesty ES-2 Universal, Vittra APS Unique, ZenChroma) and six different simplishade resin composites (G-aenial A'CHORD, Essentia Universal, OptiShade, Estelite Asteria, Filtek Universal, Filtek Z250) were used. For each group, five disk-shaped resin composites of 1 mm and 2 mm thicknesses were prepared. As a control, tooth slices with 1 mm and 2 mm thicknesses and a 99.5% pure aluminum step-wedge were used. The samples, tooth slices, and a step-wedge were placed on a photostimulable phosphor plate. Digital radiographs were taken from 30 and 40 cm distances (70 kVp, 7 mA 0.28 ms). The images were analyzed using ImageJ software to measure the mean gray values. Data were analyzed using SPSS 22 package program and Kruskal-Wallis H Test (p < 0.05). The highest radiopacity was seen in Filtek Universal at both distances and thicknesses. Omnichroma had the lowest radiopacity in all parameters. All specimens showed higher radiopacity than dentin. Except for Omnichroma 1 and 2 mm thick, Clearfil Majesty ES-2 Universal 2 mm thick, samples showed higher radiopacities than enamel (p < 0.05). The restorative materials tested were found to be more radiopaque than dentin. The samples passed the International Organization for Standardization for radiopacity values. The radiopacity values were affected by thickness and type of materials.

Effect of Radiant Exposure on the Physical and Mechanical Properties of 10 Flowable and High-viscosity Bulk-fill Resin Composites

OBJECTIVES

To evaluate the effect of the different radiant exposures from a multipeak light curing unit on the physical and mechanical properties of flowable and high-viscosity bulk-fill resin-based composites (RBC).

METHODS

Five flowable bulk-fill RBCs (Tetric N-Flow Bulk-fill, Ivoclar Vivadent; Filtek Bulk Fill Flow, 3M Oral Care; Opus Bulk Fill Flow APS, FGM; Admira Fusion x-base, Voco and; and SDR Plus Bulk Fill Flowable, Dentsply Sirona) and five high-viscosity bulk-fill RBCs (Tetric N-Ceram Bulk-fill, Ivoclar Vivadent; Filtek One Bulk Fill, 3M Oral Care; Opus Bulk Fill APS, FGM; Admira Fusion x-tra, Voco; and SonicFill 2, Kerr) were photo-cured using a VALO Cordless light (Ultradent) for 10, 20, and 40 seconds at an irradiance of 1200, 800, or 400 mW/cm2, resulting in the delivery of 4, 8, 12, 16, 24, 32, or 48 J/cm2. Post-gel shrinkage (Shr) was calculated using strain-gauge test. The degree of conversion (DC, %) was calculated using FTIR. Knoop hardness (KH, N/mm2) and elastic modulus (E, MPa) were measured at the top and bottom surfaces. Logarithmic regressions between the radiant exposures and mechanical properties were calculated. Radiodensity was calculated using digital radiographs. Data of Shr and radiodensity were analyzed using two-way analysis of variance (ANOVA), and the DC, KH, and E data were analyzed with two-way ANOVA using split-plot repeated measurement tests followed by the Tukey test (a = 0.05).

RESULTS

Delivering higher radiant exposures produced higher Shr values (p<0.001) and higher DC values (R2=0.808-0.922; R2=0.648-0.914, p<0.001), KH (R2=0.707-0.952; R2=0.738-0.919; p<0.001), and E (R2=0.501-0.925; R2=0.823-0.919; p<0.001) values for the flowable and high-viscosity RBCs respectively. Lower KH, E and Shr were observed for the flowable bulk-fill RBCs. All bulk-fill RBCs had a radiopacity level greater than the 4-mm thick aluminum step wedge. The radiant exposure did not affect the radiopacity.

CONCLUSION

The Shr, DC, KH, and E values were highly correlated to the radiant exposure delivered to the RBCs. The combination of the higher irradiance for longer exposure time that resulted in radiant exposure between 24 J/cm2 to 48 J/cm2 produced better results than delivering 400 mW/cm2 for 40 s (16 J/cm2), and 800 mW/cm2 for 20 seconds (16 J/cm2) or 1200 mW/cm2 for 10 seconds (12 J/cm2). All the bulk-fill RBCs were sufficiently radiopaque compared to 4 mm of aluminum.

The Assessability of Approximal Secondary Caries of Non-Invasive 3D-Printed Veneers Depending on the Restoration Thickness-An In Vitro Study

To date, no scientific data is available regarding the development and radiographic assessment of approximal caries development after the insertion of 3D-printed, non-invasive veneers of different restoration thicknesses. For the present study, non-invasive veneers were fabricated from two different materials for printing and milling (Vita Enamic and VarseoSmile Crown plus). Three different restoration thicknesses (0.5, 0.7, and 0.9 mm) were selected. After digital design, leaving the approximal space free, and manufacturing of the restorations, adhesive insertion followed. All specimens were placed in a demineralizing solution for 28 days. Subsequently, a radiological and fluorescent examination was performed. The present study showed statistically significant interactions for the day (p < 0.0001) and manufacturing method (p < 0.0001) but not for restoration thickness. Additive manufactured restorations showed less radiological caries progression compared to subtractive manufactured restorations after 21 and 28 days (0.7 and 0.9 mm restoration thickness) (p < 0.0001). DIAGNOdent proved that the restoration thickness affected the caries progression within the subtractive group (p < 0.0001). Radiographic and fluorescence examination showed equivalent results regarding approximal caries assessment. For additive manufacturing, less caries progression was shown without consideration of the restoration thickness.

A Comparative Evaluation of the Radiopacity of Contemporary Restorative CAD/CAM Blocks Using Digital Radiography Based on the Impact of Material Composition

Purpose

The main purpose of this study was to assess the radiopacity of contemporary restorative computer-aided design (CAD)/computer-aided manufacturing (CAM) materials and the impact of material composition as measured by energy-dispersive X-ray spectrophotometry (EDX) on radiopacity.

Materials and Methods

Ten specimens of six CAD/CAM materials with 1 mm thickness were produced and then digitally radiographed with an aluminum (Al) step-wedge (SW) and 1 mm thick tooth slice. The specimen mean gray values (MGVs) were recorded in pixels and compared to an Al-SW, dentin, and enamel of equal thickness. For the elementary analysis of the composition of the materials, EDX was performed.

Results

The recorded MGVs ranged between 21.20 ± 4.94 and 238.5 ± 13.61 pixels. Materials were sorted according to the MGVs descendingly, Prettau, Vita Suprinity, Vita Enamic, Shofu, Pekkton, and BioHPP. Prettau and Vita Suprinity had significantly higher MGV than dentin and 1 mm thick Al. In comparison, Vita Enamic had a slightly higher value than dentin and 1 mm thick Al. Although Pekkton and BioHPP had MGV significantly lower than dentin and 1 mm thick Al, Shofu had a significantly lower value than dentin and nonsignificantly lower than 1 mm thick Al (p < 0.05). According to EDX analysis, the examined materials contained several components in varying quantities of radiopacity.

Conclusions

The radiopacity of only three studied materials exceeded the International Organization for Standardization's minimum standards (ISO).

Comparative radiopacity of pediatric dental restorative materials

Background/Aim: Radiopacity of dental restorative materials is significant to detect secondary caries, overhangs, and voids. This study aimed to evaluate whether radiopacity of dental restorative materials used in pediatric dentistry was sufficient. Material and Methods: Specimens of 2 mm thickness and 4 mm diameter were prepared in the plastic molds. Six composite materials, one compomer material, and one conventional glass ionomer cement were used and three specimens of each material were prepared. Three radiographs were taken from dental restorative materials and aluminum step wedge. Digital images obtained were recorded. Mean gray values of the dental restorative materials and aluminum step wedge were measured on digital radiographs. Results: All composite resins displayed higher radiopacity values than an equal thickness of 2 mm Al. Posterior composite (201.62±1.99 MGV) showed higher radiopacity value than the anterior composite (86.19 ±1.45 MGV). There was no significant difference in radiopacity values of different shades of the same composite. There was no significant difference in radiopacity values between glass ionomer cement and compomer. Glass ionomer cement showed higher radiopacity value (8.11 mm Al) than anterior composite (5.31 mm Al). Conclusions: Radiopacity values of dental materials used in this study were sufficient. Both resin materials and the glass ionomer cement had sufficient radiopacity values. Posterior composite showed the highest radiopacity value. Radiopacity values were not affected by different shades.

Evaluation of the radiopacity of restorative materials with different structures and thicknesses using a digital radiography system

Purpose

The aim of this study was to evaluate the radiopacities of various types of restorative materials with different thicknesses compared with enamel, dentin, and aluminum.

Materials and Methods

Four bulk-fill resins, 2 hybrid ceramics, 2 micro-hybrid resin composites, 6 glass ionomer-based materials, 2 zinc phosphate cements, and an amalgam were used in the study. Twelve disk-shaped specimens were prepared from each of 17 restorative materials with thicknesses of 1 mm, 2 mm, and 4 mm (n=4). All the restorative material specimens with the same thickness, an aluminum (Al) step wedge, and enamel and dentin specimens were positioned on a phosphor storage plate and exposed using a dental X-ray unit. The mean gray values were measured on digital images and converted to equivalent Al thicknesses. Statistical analyses were performed using 2-way analysis of variance and the Bonferroni post hoc test (P<0.05).

Results

Radiopacity was significantly affected by both the thickness and the material type (P<0.05). GCP Glass Fill had the lowest radiopacity value for samples of 1 mm thickness, while Vita Enamic had the lowest radiopacity value for 2-mm-thick and 4-mm-thick samples. The materials with the highest radiopacity values after the amalgam were zinc phosphate cements.

Conclusion

Significant differences were observed in the radiopacities of restorative materials with different thicknesses. Radiopacity was affected by both the material type and thickness.

One-Year Clinical Performance of the Fast-Modelling Bulk Technique and Composite-Up Layering Technique in Class I Cavities

The aim of this study was to assess the one year clinical performance of a new application method, the Fast-Modelling Bulk Technique (FMBT), in comparison to the Composite-Up Layering Technique (CULT) in posterior cavities. Thirty patients with two class I cavities on permanent human molars were enrolled in the present study. A total of sixty class I cavities were prepared and randomly divided according to the restoration technique used: 30 cavities restored by incremental layering technique and modelling of the last layer with Composite-Up Technique (CUT) using the composite Filtek Z250XT (3M ESPE; St. Paul, MN, USA) and the other 30 restored by Bulk Filling technique and modelling of the last layer by Fast-Modelling Technique (FMT) using the composite Filtek Bulk Fill Posterior Restorative (3M ESPE; St. Paul, MN, USA). Restorations were evaluated for up to one year by two observers according to Federation Dentaire Internationale (FDI) criteria, through clinical and radiological exams. Exact Fisher tests were used for statistical analysis. (p ≤ 0.05). From a biological perspective, at baseline, teeth restored with both techniques did not reveal any postoperative sensitivity. However, with time, FMBT showed less postoperative sensitivity and therefore more desirable results than CULT with a nonsignificant difference after one year (p > 0.05). Concerning secondary caries, fracture of the material, and marginal adaptation, no significant difference was noted between both techniques (p > 0.05). Regarding marginal staining, CULT resulted in more staining with a significant difference, as compared to FMBT (p < 0.05). Upon radiological examination, FMBT showed a good marginal fit during the first year, whereas CULT showed small empty voids from baseline with a nonsignificant difference (p = 1.00). After one year of clinical function, both techniques showed promising results. The present study indicates that the new FMBT could have a positive effect on the marginal staining of resin composite.

Evaluation of radiopacities of CAD/CAM restorative materials and resin cements by digital radiography

OBJECTIVE

This study aims to compare the radiopacities of computer-aided design/computer-aided manufacture (CAD/CAM) blocks and the adhesive cements used for their bonding.

MATERIALS AND METHODS

1 ± 0.2 mm thick specimens were obtained from six different CAD/CAM blocks (Incoris TZI, IPS e.max CAD, Vita Mark II, Cerasmart, Vita Enamic, and Vita Suprinity), four different adhesive resin cements (Panavia F2.0, Variolink Esthetic DC, RelyX Unicem Aplicap, G-CEM LinkAce), and a tooth. Radiographs of the specimens from each group, a tooth section, and an aluminum (Al) step-wedge were acquired. The radiopacity values of the materials were calculated as equivalents of Al thickness using the gray level values. The data were statistically analyzed using one-way ANOVA and Tukey HSD tests.

RESULTS

All the materials except Cerasmart and Vita Enamic had significantly higher radiopacity values than dentin (p < 0.05). Of the assessed blocks, the highest radiopacity value was observed in Incoris TZI, and the lowest radiopacity value was observed in Vita Enamic. Variolink Esthetic DC and RelyX Unicem Aplicap showed significantly higher radiopacity (p < 0.05) than the other adhesive cements, including enamel and dentin.

CONCLUSIONS

In this study, the majority of the CAD/CAM materials and all the adhesive resin cements were found to have sufficient radiopacity for prosthetic restorations according to the criteria set by the International Organization for Standardization (ISO).

CLINICAL RELEVANCE

From a clinical and biological point of view, materials should be chosen according to their radiopacity and other properties, such as biocompatibility and esthetics. If the selected restorative CAD/CAM blocks have a radiopacity value less than or equal to dentin, cements with higher radiopacity values are recommended to facilitate radiological diagnoses for periphery and interface of restorations.

Effect of image acquisition parameters on the radiopacity of bulk-fill and nanocomposite resins

OBJECTIVE

This study evaluated the radiopacity of 2 bulk-fill resins (SonicFill and Filtek Bulk Fill) and a nanocomposite (Filtek Z350 XT) resin compared with enamel, dentin, and aluminum as measured with different exposure parameters.

STUDY DESIGN

Resin disks were radiographed together with a 1-mm human tooth section and an aluminum stepwedge, at exposure times of 0.2 and 0.32 s, and source-image (S-I) distances of 30 and 40 cm, using complementary metal oxide semiconductor (CMOS) and photostimulable phosphor systems. Grayscale values were measured using ImageJ software. Paired Student t tests were used to compare the effect of the receptor on grayscale values for each material. Analysis of variance was used to evaluate the effects of receptor, exposure parameters, and the resins on radiopacity.

RESULTS

All resins exhibited greater radiopacity scores than enamel and were significantly different from each other. Filtek Z350 produced the lowest radiopacity values, whereas SonicFill produced the highest. The radiopacity values were higher on images acquired with CMOS receptors. Receptor type, exposure time, S-I distance, and material, as well as many interactions of these parameters, affected the radiopacity of the resins.

CONCLUSION

The tested resins complied with ISO 4049. Exposure parameters and digital receptors affected their radiopacity.

Evaluation of Radiopacity of Luting Cements Submitted to Different Aging Procedures

PURPOSE

To evaluate the radiopacity of luting cements submitted to different aging procedures.

MATERIALS AND METHODS

Twenty discs (1 × 4 mm) of each of the following cements were prepared: zinc phosphate, RelyX Luting 2, Variolink 2, AllCem, RelyX U200, Multilink, Panavia F2.0, and RelyX ARC. Then, they were randomly divided into two groups (n = 10/group), according to the aging procedure: thermal cycling group and water storage group. Before and after aging procedures, specimens were x-rayed with an aluminum step-wedge (11 steps, 1 mm thick each) and three dental slices (1 mm thick). The radiopacity was evaluated by means of optical density, which was measured using ImageJ software. The values were converted into millimeters of aluminum with a logistic regression calibration curve. The data were analyzed by one-way ANOVA and Tukey post-hoc test (α = 0.05).

RESULTS

In the thermal cycling group, RelyX Luting 2, RelyX U200, and Panavia F2.0 showed a statistically significant reduction in radiopacity (p < 0.05). In the water storage group, all cements showed a significant reduction in radiopacity (p < 0.05), and RelyX Luting 2 and Panavia F2.0 performed below the desired ISO 4049 standard.

CONCLUSIONS

The radiopacity of luting cements can decrease after aging, especially after 1-year water storage.

Radiopacity of contemporary luting cements using conventional and digital radiography

Purpose

This study evaluated the radiopacity of contemporary luting cements using conventional and digital radiography.

Materials and Methods

Disc specimens (N=24, n=6 per group, ø7 mm×1 mm) were prepared using 4 resin-based luting cements (Duolink, Multilink N, Panavia F 2.0, and U-cem). The specimens were radiographed using films, a complementary metal oxide semiconductor (CMOS) sensor, and a photostimulable phosphor plate (PSP) with a 10-step aluminum step wedge (1 mm incremental steps) and a 1-mm-thick tooth cut. The settings were 70 kVp, 4 mA, and 30 cm, with an exposure time of 0.2 s for the films and 0.1 s for the CMOS sensor and PSP. The films were scanned using a scanner. The radiopacity of the luting cements and tooth was measured using a densitometer for the film and NIH ImageJ software for the images obtained from the CMOS sensor, PSP, and scanned films. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests.

Results

Multilink (3.44–4.33) showed the highest radiopacity, followed by U-cem (1.81–2.88), Panavia F 2.0 (1.51–2.69), and Duolink (1.48–2.59). The R² values of the optical density of the aluminum step wedge were 0.9923 for the films, 0.9989 for the PSP, 0.9986 for the scanned films, and 0.9266 for the CMOS sensor in the linear regression models.

Conclusion

The radiopacities of the luting materials were greater than those of aluminum or dentin at the same thickness. PSP is recommended as a detector for radiopacity measurements because of its accuracy and convenience.

Longitudinal Evaluation of Radiopacity of Resin Composites: Influence of Photoactivation and Accelerated Photoaging

This study aimed to assess longitudinally the radiopacity of resin composites under the influence of photoactivation and photoaging processes. Ten specimens (1 mm thick and 4 mm in diameter) of three different microhybrid resin composites, Filtek Z250 XT (R1), TPH 3 Spectrum (R2), and Opallis (R3), were prepared for this study. For longitudinal assessment of radiopacity, radiographic images were obtained five times. The first time (T1), the specimens were not photoactivated; the second time (T2), the specimens were photoactivated; and the next three times, photoaging was carried out, with images obtained at 24 hours (T3), 48 hours (T4), and 72 hours (T5) after this process. The photoaging was conducted using LED light (700 lumens, 9 W, 6400 k) under controlled environmental conditions at 37°C (±1°C) and 65% (±5%) relative humidity. The digital system DIGORA Optime was used. The digital images were measured using the histogram function, and then the pixel intensity values were converted into mmAl (the standard unit of radiopacity) using a linear regression function, with minimal adjustment of R² ≥ 0.9. Data in mmAl were statistically analyzed using an analysis of variance (α=0.05). R2 resin composite showed higher values of radiopacity, R1 resin composite showed intermediate values, and R3 resin composite showed lower values. Only at T1 did the higher radiopacity of R2 composite differ significantly from other groups ( p = 0.0000). After application of treatments (photoactivation and photoaging), all radiopacity values were similar ( p-values to T2=0.0507, T3=0.0536, T4=0.0502, T5=0.0501) due to consecutive increase of radiopacity of R1 and R3 composites from T2. Photoactivation and photoaging processes influenced the radiopacity, but changes occurring in the degree of radiopacity were dependent on the composition and chemical characteristics of each composite used.

Comparative study of radiopacity of resin-based and glass ionomer-based bulk-fill restoratives using digital radiography

This study investigated the radiopacity values of glass ionomer- and resin-based bulk-fill restoratives of different thicknesses using digital radiography. Two glass ionomer-based and three resin-based bulk-fill restoratives, and a conventional composite were studied. Five disc-shaped specimens were prepared from each of these materials at three different thicknesses; specimens of enamel and dentin with the same thicknesses were also prepared. Materials were placed over a complementary metal oxide-semiconductor sensor together with the tooth specimen and an aluminum step-wedge, and then exposed using a dental X-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs), which were converted to equivalent aluminum thicknesses. Two-way ANOVA was used to investigate the significance of differences among the groups. The GCP Glass Fill specimens showed the lowest radiopacity values, and the Quixfil specimens had the highest values. All materials had higher radiopacity values than enamel and dentin, except for GCP Glass Fill, which had a radiopacity similar to that of enamel. The resin-based bulk-fill restoratives had significantly higher radiopacity values than glass ionomer-based restoratives. All of the tested materials showed radiopacity values higher than that of dentin, as recommended by the ISO.

Radiopacity of Composite Luting Cements Using a Digital Technique

PURPOSE

The aim of this in vitro study was to evaluate the radiopacity of 20 common dental composite luting materials using a digital technique.

MATERIALS AND METHODS

A 1-mm-thick specimen of each material with a human tooth slice and aluminium step wedge were tested using digital radiographs under four combinations of exposure and voltage. The radiopacity in pixels was determined using computer software. The equivalent thickness of aluminium for each material was then calculated based on the calibration curve.

RESULTS

All tested materials except one had higher radiopacity than dentin (p > α; α  =  0.01), and 80% of the materials had radiopacity above enamel value (p > α; α  =  0.01). Moreover, 40% of tested materials had radiopacity of three times above the minimal International Organization for Standardization (ISO) values for composite luting cements. At all exposure values, the highest radiopacity was for Solocem and Multilink groups of materials, at three to six times above dentin radiopacity. Only Variolink Veneer showed radiopacity below dentin and enamel.

CONCLUSIONS

Composite luting materials should have radiopacity above ISO values or greater than the dentin or enamel equivalent. The highest radiopacity values were for the Solocem and Multilink family composite luting cements. Clinicians should choose materials with high radiopacity values, and manufacturers should be aware of the radiopacity values when introducing materials on the market.

Radiopacity of Methacrylate and Silorane Composite Resins Using a Digital Radiographic System

The aim of this study was to evaluate the radiopacity of silorane and methacrylate resin composites, comparing them to the enamel, dentin, and aluminum penetrometer using a digital image. From six resin composites (Filtek™ P90, Filtek Z350, Filtek Z350 XT flow, Tetric Ceram, TPH Spectrum, and SureFil SDR flow) cylindrical disks (5 × 1 mm) were made and radiographed by a digital method, together with a 15-step aluminum step-wedge and a 1 mm slice of human tooth. The degree of radiopacity of each image was quantified using digital image processing. The mean values of the shades of gray of the tested materials were measured and the equivalent width of aluminum was calculated for each resin. The results of our work yielded the following radiopacity values, given here in descending order: Tetric Ceram > TPH > SDR > Z350 > Z350 flow > P90 > enamel > dentin. The radiopacity of the materials was different both for the enamel and for the dentin, except for resin P90, which was no different than enamel. In conclusion, silorane-based resin exhibited a radiopacity higher than dentin and closest to the enamel; a large portion of the methacrylate-based flow and conventional resins demonstrated greater radiopacity in comparison to dentin and enamel.

Comparative study of the radiopacity of resin cements used in aesthetic dentistry

PURPOSE

The aim of this study was to compare the radiopacity of 6 modern resin cements with that of human enamel and dentine using the Digora digital radiography system, to verify whether they meet the requirements of ANSI/ADA specification no. 27/1993 and the ISO 4049/2000 standard and assess whether their radiopacity is influenced by the thickness of the cement employed.

MATERIALS AND METHODS

Three 3-thickness samples (0.5, 1 and 1.5 mm) were fabricated for each material. The individual cement samples were radiographed on the CCD sensor next to the aluminium wedge and the tooth samples. Five radiographs were made of each sample and therefore five readings of radiographic density were taken for each thickness of the materials. The radiopacity was measured in pixels using Digora 2.6 software. The calibration curve obtained from the mean values of each step of the wedge made it possible to obtain the equivalent in mm of aluminium for each mm of the luting material.

RESULTS

With the exception of Variolink Veneer Medium Value 0, all the cements studied were more radiopaque than enamel and dentin (P<.05) and complied with the ISO and ANSI/ADA requirements (P<.001). The radiopacity of all the cements examined depended on their thickness: the thicker the material, the greater its radiopacity.

CONCLUSION

All materials except Variolink Veneer Medium Value 0 yielded radiopacity values that complied with the recommendations of the ISO and ANSI/ADA. Variolink Veneer Medium Value 0 showed less radiopacity than enamel and dentin.

Radiopacity of Esthetic Post Materials: Evaluation with Digital Analysis Technique

PURPOSE

To evaluate the radiopacity of five post materials using a digital image analysis method.

MATERIALS AND METHODS

Twelve specimens from each post type (two zirconia and three fiber based) of 2 mm in thickness were obtained using a diamond blade mounted on a cutting machine, and digital radiographs were taken along with aluminum step-wedge and dentin discs under standard exposure conditions. The mean gray-values of specimens were measured using a computer graphics program. Data were analyzed using one-way ANOVA followed by Holm-Sidak multicomparison test (p = 0.05).

RESULTS

The highest radiopacity was observed in custom zirconia (5.842 millimeters of equivalent Al [mmAl]), and the lowest value was detected with FRC-Postec (Ivoclar Vivadent) (1.716 mmAl). Significant differences were revealed between the radiopacity values among all groups (p < 0.05), except the Zr post materials (p = 0.56).

CONCLUSIONS

All tested post materials had higher radiopacity than dentin. Further studies will be required to clarify optimum radiopacity properties of the post materials to provide a precise clinical observation.

Evaluation of the Radiopacities of Bulk-fill RestorativesUsing Two Digital Radiography Systems

This study investigated the radiopacity values of bulk-fill restoratives by using two digital radiography systems. Nine bulk-fill restoratives and a conventional composite were used in the study. Six disc-shaped specimens were prepared from each of these materials, three each at thicknesses of 1 mm and 2 mm, and tooth slices with these same thicknesses were obtained. As a control, an aluminum step wedge varying in thickness from 0.5 to 10 mm in was used. Three specimens of each of the materials, together with the tooth slice and the aluminum step wedge, were placed over a complementary metal oxide semiconductor (CMOS) sensor and a storage photostimulable phosphor (PPS) plate system and exposed using a dental x-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs). Five measurements were obtained from each of the restorative materials, the enamel, the dentin, and the stepwedge. The MGVs were converted to the equivalent aluminum thicknesses. Three-way analysis of variance (ANOVA) was used to determine the significance of the differences among the groups. A Tukey test was applied for pairwise comparisons (p&lt;0.05). All composite-based restoratives were found to have greater radiopacities than enamel or dentin. Equia Fil had the lowest radiopacity value. Radiopacity increased as the thicknesses of the restorative material increased. The CMOS system showed significantly higher radiopacity values than the PSP system. In conclusion, all investigated bulk-fill restoratives passed the International Organization for Standardization and American National Standard Institute/American Dental Association requirements for radiopacity values when evaluated with the two digital radiography systems.

The Temperature Dependence of Micro-Leakage between Restorative and Pulp Capping Materials by Cu Diffusion

We used the Cu ions for the leakage analysis between pulp capping and restorative materials. Theoretically, Cu has more advantages than Ag ions due to their smaller radii (r_Cu²⁺=73 pm and r_Ag²⁺=94 pm), lower mass density (d_Cu=8.96 g/cm³ and d_Ag=10.49 g/cm³) and higher radio opacity which can be more useful by X-ray or EDX detectors, cheaper price and more abundance in planet when compared with Ag element which is generally used in the leakage studies. The micro leakage between dental restorations and pulp capping materials has been determined by using Micro Computed Tomography, Scanning Electron Microscopy and EDX analysis. It is found that the leakage has temperature dependent mechanism which increases with the increasing temperature. As a result, using Cu solution for leakage studies in dentine is an effective and easy method which can be used in dental science.

Radiopacity for Contemporary Luting Cements Using Digital Radiography under Various Exposure Conditions

PURPOSE

This study examined the radiopacity of contemporary luting cements using direct digital radiography under a range of exposure conditions.

MATERIALS AND METHODS

Disc specimens (N = 80, n = 10 per group, ø5 mm × 1 mm) were prepared from 8 resin-based luting cements (BisCem Clearfil SA Luting, Duolink, Maxcem Elite Multilink Speed, Panavia F 2.0, RelyX Unicem Clicker, V-link). The specimens were radiographed using a charge-coupled device sensor along with an 11-step aluminum step wedge (1.5-mm incremental steps) and 1-mm-thick tooth cut using five tube voltage/exposure time setups (60 kVp, 0.10/0.08 seconds; 70 kVp, 0.10/0.08/0.06 seconds) at 4 mA and 30 cm. The radiopacity of the specimens was compared with that of the aluminum step wedge and human enamel and dentin using NIH ImageJ software (available at http://rsb.info.nih.gov/ij/). A linear regression model for the aluminum step wedge was constructed, and the data were analyzed by ANOVA and Duncan post hoc test.

RESULTS

Maxcem Elite (5.142 to 5.441) showed the highest radiopacity of all materials, followed in order by Multilink Speed (3.731 to 3.396) and V-link (2.763 to 3.103). The radiopacity of Panavia F 2.0 (2.025 to 2.429), BisCem (1.825 to 2.218), Clearfil SA Luting (1.692 to 2.145), Duolink (1.707 to 1.993), and RelyX Unicem Clicker (1.586 to 1.979) were between enamel (2.117 to 2.330) and dentin (1.302 to 1.685). The radiopacity of 70 kVp conditions was higher than that of the 60 kVp conditions.

CONCLUSIONS

The radiopacities of the tested luting materials were greater than those of dentin or aluminum, satisfying the criteria of the International Organization for Standardization, and they differed significantly from each other in the exposure setups.

Influence of Radiopacity of Dental Composites on the Diagnosis of Secondary Caries: The Correlation Between Objective and Subjective Analyses

This study aimed to objectively evaluate the radiopacity of different dental composites and their subjective influence on diagnosing secondary caries–like lesions and how these results correlate. For objective analysis, three resin specimens (1 mm thick, with a 4-mm internal diameter) were made with four composites: 1) Charisma; 2) Filtek Z250; 3) Prisma AP.H; and 4) Glacier. Three human teeth were selected and then mesio-distally sectioned (1 mm thick) to make the dental specimens. An aluminum (Al) wedge (12 steps, 1 mm thick, 99.8% purity) was used as an internal standard to calculate the radiopacity. For subjective analysis, 20 human teeth were selected and then prepared with a mesio-occluso-distal (MOD) inlay cavity, with half the teeth receiving a round cavity to simulate the carious lesion. The MOD was restored using the composites at four different times. Standardized radiographs were acquired and then digitized (300 dpi and eight-bit TIFF) for both analyses. A histogram objectively measured the pixel intensity values of the images, which were converted into millimeters of Al using linear regressions. Eight observers subjectively evaluated the images using a five-point rating scale to diagnose the caries. The data were statistically analyzed using the Student t-test, the Kappa test, diagnostic testing, and the Pearson correlation coefficient (α=0.05). All materials showed radiopacity values compatible with dental tissues (p&gt;0.05); Glacier was similar to dentin and Prisma AP.H was similar to enamel, while the remaining materials showed a middle radiopacity. Prisma AP.H and Glacier differed (p&lt;0.05) in relation to their accuracy to caries diagnosis, with Glacier having greater accuracy. There was a correlation between objective and subjective analyses with negative linear dependence. An increase in the material's radiopacity could have a subjectively negative influence on the diagnosis of secondary caries; thus, an ideal radiopacity for a dental composite is closer to the dentin image and produces similar attenuation to X-rays than does dentin.

Radiopacity of restorative composites by conventional radiograph and digital images with different resolutions

Purpose

This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digital images with different resolutions.

Materials and Methods

Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using #4 sized intraoral film and digital images were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographic images. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukey's test (p<0.05), considering the material factor and then the radiographic method factor, individually.

Results

The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites.

Conclusion

The high speed mode of digital imaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

A study of composite restorations as a tool in forensic identification

Introduction:

Comparing ante-mortem and post-mortem dental data is a principal method of identification in forensic odontology. Radiographic images of amalgam have been used in dental forensics for identification due to their unique appearance.

Aim:

The aim of this study was to investigate whether radio-opaque composite restorations have a potential for identification in forensic odontology.

Materials and Methods:

Thirty typodont mandibular first molar teeth were prepared with Class-II (proximo-occlusal) cavities and restored with a radio-opaque composite (Tetric N-Ceram). Two sets of standardized radiographs were taken from the 30 teeth, keeping the radiological parameters constant. One set of these 30 radiographs was named as SET 1. Ten randomly chosen radiographs from the other set and two other radiographs of Class-II composite restorations in typodont teeth constituted SET 2. Thirty dentally trained examiners were asked to match the 12 radiographic images of SET 2 with those of SET 1.

Results:

The results show that 15 examiners were able to correctly match all the 12 images. Statistical analysis was done using kappa statistical test.

Conclusion:

This study shows that, if the post-mortem radiographs are accurate duplicates of ante-mortem radiographs of composite restorations, then the shape of the composite restoration is unique and can be used for identification.

Radiopacity of Flowable Composite by a Digital Technique

The aim of this in vitro study was to evaluate the radiopacity of 19 current dental flowable composite materials by a digital technique. Digital radiographs were obtained with a CCD sensor using an aluminum step wedge, a 1-mm-thick tooth slice, and a 1-mm-thick flowable composite specimen using five different combinations of exposure and voltage. The radiopacity in pixels was determined using Digora 2.6. software. The equivalent thickness of aluminum for each material was then calculated based on the calibration curve. All of the tested flowable composite materials had higher radiopacities than that of dentin, but in almost every combination of exposure and voltage, there were some composite materials that exhibited radiopacities equal to or slightly greater than enamel p&gt;α; α=0.01). Of the flowable composite materials tested, 37% showed lower radiopacities than enamel, and 21% of the tested materials had higher radiopacities than the 3-mm aluminum equivalent. The highest radiopacity at all exposure values was produced by the Majesty Flow and Charisma Opal Flow materials, which had radiopacities almost twice that of enamel. Flowable composite materials should have radiopacities greater than that of enamel (ISO 4049), an important consideration for the introduction of new materials to the market. The digital radiopacity analysis techniques used in this study provide an easy, reliable, rapid, and precise method to characterize radiopacity of dental flowable composite materials.

Influence of Silica and Zirconia Particles as Filler Loading on the Radiopacity of Dental Resin Composites

The aim of this study is to evaluate the radiopacity of silica (SiO2) and zirconia (ZrO2) particles dispersed in a bisphenol-a-glycidyl methacrylate (Bis-GMA) as a base resin and triethylene glycol dimethacrylate (TEGDMA) as a diluent. The fillers were mixed separately with bis-GMA/TEGDMA monomers, in proportions of 40, 50 and 60 wt.%. A resin matrix containing 0 wt.% filler was used as the control composition to evaluate the effect of filler loading on the radiopacity. Samples of the composites with 2.5 mm thickness were compared their radiopacity with the same thickness of the standard aluminum plate. The radiopacity of both resin matrix/SiO2and resin matrix/ZrO2composites increased gradually as the filler loading increased. The resin matrix/ZrO2composites possessed radiopacity higher than the standard aluminum plate. The increase of filler loading showed highly significant differences in the radiopacity as tested by ANOVA (P= 0.000).