Difference In Radiopacity Research Articles

Differences in radiopacity among CT contrast agents and concentrations: A quantitative study.

Several studies in the literature have attempted to subjectively assess the degree of visualization of different neurovascular structures using different contrast agents and concentrations. Given the recent contrast shortages, we aim to objectively compare the radiopacity achieved with four angiographic contrast agents used in clinical practice. Isovue 370, Visipaque 320, Omnipaque 300, and Isovue 300 were each drawn up at 25%, 50%, 75%, and 100% concentrations and compared against normal saline and air syringes. CT scans were obtained, and regions of interest were analyzed for radiopacity using Hounsfield unit (HU) measurements. An aneurysm model with different contrast concentrations was also scanned and dimensions compared. Two-tailed t-tests and Cohen's d coefficients were applied to assess for differences in mean HU measurements. Isovue 370 and Isovue 300 had the highest and lowest mean HU, respectively (p<.001). Visipaque 320 at 25% concentration had the lowest mean HU at -.76. Statistically similar agents (p<.05) were Visipaque 320 and Omnipaque 300 at a 100% concentration (p=.30), and Omnipaque 300 and Isovue 300 at a 25% concentration (p=.73). Aneurysm dimensions among Isovue 370, Visipaque 320, and Omnipaque 300 were all similar, whereas with Isovue 300, the dimensions were significantly smaller (p<.05). Isovue 370 provides the highest HU radiopacity and the most accurate aneurysm measurements. Angiographic measurements obtained with Isovue 300 may underestimate the actual aneurysmal dimensions. Visipaque 320 and Omnipaque 300 at 100% concentration have similar mean HUs and are beneficial for patients with chronic kidney or cardiac disease.

Importance of radiological examination in the evaluation of canal fillings performed with bioceramic sealers.

Bioceramic-based fillers have been evaluated in several in vitro studies but in vivo studies are still limited. The present study examined 36 postoperative radiographic analyses that were divided into four groups, of which three used bioceramic-based fillers, namely Total Fill, BioRoot RCS and Biodentine, while the fourth group was used as control and implemented the resin-based AH Plus Jet sealer. The present results did not indicate significant differences in radiopacity between sealers at a certain level of obturation. Biodentine-based fillers have a radiodensity close to that of dentin, which makes it difficult for the physician to radiologically assess the correctness of the canal filling.

Is the radiopacity of CAD/CAM aesthetic materials sufficient?

ObjectivesThis study was designed to investigate CAD/CAM restorative blocks and other resin-based materials by (i) determining their chemical composition, (ii) comparing their radiopacity and (iii) correlating their radiopacity with specimen thickness. MethodsDisk specimens, of 1and 2 mm thickness (n = 3), were prepared from five CAD/CAM and six resin-based composites (RBCs). The CAD/CAM resin-composites included aesthetic types: CeraSmart (CS), Grandio Blocs (GB), Lava Ultimate (LU), plus a polymer infiltrated ceramic Vita Enamic (VE), and a feldspathic ceramic Vita Mark II (VM II). The six RBCs were for different clinical applications: direct filling, flowable, bulk fill, base and two luting cements. The specimens were radiographed alongside an aluminium step wedge and a tooth section. Digital images were analysed, and the radiopacity of each specimen was determined according to ISO 1311/2014. Statistical analyses of radiopacity, expressed as mm Al (n = 15), were carried out using the Kruskal-Wallis test followed by pairwise comparisons (α = 0.05). ResultsRadiopacities of CAD/CAM materials were, in ascending order, VE, VM II, CS, LU, and GB. At 1 mm thickness, the radiopacities of all CAD/CAM specimens were matching or slightly lower than enamel. At 2-mm thickness, the resin composite blocks were significantly more radiopaque than the ceramics VE and VM II (p < 0.0001). No statistically significant differences in radiopacity were detected between the 1-mm thick infiltrated ceramic, enamel, dentin and various resin composites except for filling and bulk fill types. The radiopacity of polymer-infiltrated ceramics was low despite the presence of radiopacifying elements and high filler content. SignificanceIdentifying thin restorations in standard radiographs is necessary with the development and expanded application of ‘digital’ dental materials in restorative treatment. This study confirmed the joint influence of composition and thickness on radiopacity. CAD/CAM restorative materials showed thickness-dependant radiopacity. But polymer-infiltrated ceramics were fairly radiolucent. There is a need to revisit radiopacity requirements for CAD/CAM restorative materials.

Radiopacity of premixed and two-component Calcium silicate-based Root Canal sealers

Background/Aim: Radiopacity enables radiographic visualization, which is significant in diagnostic procedures and assessment of the quality of endodontic filling. It is important to compare newly developed endodontic sealers with materials that are already in clinical use in order to promote evidence-based dentistry. The aim of our study was to evaluate radiopacity of different calcium silicate-based sealers in comparison with control, epoxy resin-based sealer. The null hypothesis was that there were no statistically significant differences in radiopacity of the tested sealers. Material and Methods: Premixed (TotalFill BC Sealer, EndoSequence BC Sealer, Ceraseal, Bio-C Sealer), two-component (BioRoot RCS, MTA Fillapex, Bioceramic Root Canal Sealer, GuttaFlow Bioseal) calcium silicate-based sealers and AH Plus, as a control, were used. Specimens were radiographed using a Radiovisiography (RVG-4) CCD (charge-coupled devices)-based digital sensor. Results: Ceraseal had the highest, while Bioceramic Root Canal Sealer had the lowest radiopacity. Bioceramic Root Canal Sealer and MTA Fillapex had radiopacity significantly lower than all other sealers. Radiopacity level of AH Plus, was similar to premixed and significantly higher than radiopacities of all two-component endodontic sealers. Conclusions: Calcium silicate-based sealers radiopacity ranged from slightly above minimal required value (3mm), to a value higher than control sealer. Premixed endodontic sealers showed similar radiopacity as AH Plus which suggests that their clinical performance, in terms of visibility on dental radiograms, should be similar

The difference in radiopacity of microhybrid, nanofiller and nanohybrid composite resins with conventional periapical radiographic techniques

Objective: The radiopacity of dental composite restorative materials is important since it allows assessment of the integrity of composite restorations, accurate diagnosis of secondary caries development and evaluation of the interface between the com-posite restorative material and the tooth structure on the new materials introduced in the market nowadays. The purpose of this observation is to determine the differences of microhybrid, nanofiller and nanohybrid composite resins on their radiopacity using conventional periapical radiography techniques. Methods: Composite resins samples were divided into three groups; 30 samples each. Group I were microhybrid composite resin. Group II were nanofiller composite resin. Group III were nanohybrid composite resin. Each specimen was placed on a dental film and exposed using conventional radiographic techniques with the specification of 70 kVp, 8mA and 0.25s, then processed using instant film procedures. Observations were carried out using the densitometer. The results of calculations were analyzed by using the one way Anova test. Results: Significant radiopacity dif-ferences were occurred in those three groups (p&lt;0.05). Nanohybrid composite resin (2.32 mmAl) was significantly more ra-diopaque than microhybrid composite resin (2.20 mmAl) and nanofiller composite resin (2.10 mmAl). Conclusion: There are differences between microhybrid, nanofiller and nanohybrid composite resins. Resins that have the highest to the lowest ra-diopacity levels are nanohybrid, microhybrid, and nanofiller composite resin.

Radiopacity of calcium silicate-based endodontic sealers using digital imaging

Introduction. Adequate radiopacity of endodontic sealers allows radiographic visualization, assessment of root canal filling quality and its clinical follow-up after obturation. The aim of our study was to evaluate the radiopacity of Bio-Root RCS, MTA Fillapex, Bioceramic Root Canal Sealer, GuttaFlow Bioseal in comparison to AH Plus sealer, as a gold standard in clinical practice. Material and methods. Sealer specimens, 2 mm thick and 5 mm in diameter, were radiographed with an aluminum stepwedge using digital imaging system. Radiographic densities of the specimens were shown as mean greyscale values (Adobe Photoshop CS4 software) and expressed as mmAl/mm of the material. ANOVA with a post hoc Tukey test was used, significance was set at 0.05. Results. Differences in radiopacity between tested endodontic sealers were statistically significant except the difference between BioRoot RCS and GuttaFlow Bioseal. Conclusion. Radiopacities of all evaluated calcium silicate-based sealers were higher than minimal values recommended by standards. AH Plus sealer had the highest radiopacity, while calcium silicate-based sealers showed lower values, from BioRoot RCS, followed by GuttaFlow Bioseal, to MTA Fillapex, in descending order, and Bioceramic Root Canal Sealer with the lowest values.

Radiopacity of computer-aided design/computer-aided manufacturing composite resin blocks.

This study aimed to clarify the degree of difference in radiopacity between sixteen CAD/CAM composite resin blocks, one ceramic block, and teeth of the same thickness on radiographs. The radiographic density of CAD/CAM composite resin blocks was measured and the results were compared with the corresponding values for enamel and dentin. Additionally, the study analyzed the constituent elements of each type of CAD/CAM composite resin block and conducted an examination to identify those elements exerting an influence on radiopacity. Compared to the enamel, there were five blocks with significantly higher radiopacity, two blocks with the same level in radiopacity, and ten blocks with notably lower radiopacity. Compared to the dentin, there were ten blocks with significantly higher radiopacity, one block with the same level in radiopacity, and six blocks with notably lower radiopacity. All of the CAD/CAM composite resin blocks for molars contained barium and strontium.This result suggests that the addition of heavy metals, for example, barium, strontium, and zirconium, would be effective in providing CAD/CAM composite resin blocks with radiopacity.

Differences in Radiopacity, Surface Properties, and Plaque Accumulation for CAD/CAM-Fabricated vs Conventionally Processed Polymer-based Temporary Materials.

As temporary materials are often used in prosthetic dentistry, there is need to investigate their behavior in the oral environment. Parameters such as surface roughness and surface free energy correlate to the level of plaque adhesion, which can impact gingival health.

Influence of N-(2-hydroxyethyl)acrylamide addition in light- and dual-cured resin cements

ObjectiveTo develop experimental light-cured (L) and dual-cured (D) resin cements containing N-(2-hydroxyethyl)acrylamide and evaluate the physicochemical and optical properties. MethodsExperimental resin cements were formulated using bisphenol A-glycidyl dimethacrylate (70%) and 2-hydroxyethyl methacrylate (30%), in the control groups, and, bisphenol A-glycidyl dimethacrylate (70%) and N-(2-hydroxyethyl)acrylamide (30%). Polymerization kinetics were evaluated by differential scanning calorimetry (n = 3), softening in solvent (ΔKHN) evaluated by the difference of Knoop microhardness before (KHN1) and after (KHN2) ethanol solution immersion (n = 5), radiopacity in mmAl (n = 5), film thickness (n = 3) and color stability were evaluated. Mechanical properties as ultimate tensile strength (UTS) and micro-shear bond strength (μSBS) were analyzed immediately and after 6 months. Results were analyzed using ANOVA, Tukey’s test and Student’s t-test (α = 0.050). ResultsThe LHEAA1 group had no statistical difference from the control group regarding polymerization kinetics, KHN1, ΔKHN and color stability (p > 0.050). In dual-cured cements, the acrylamide groups presented a lower degree of conversion and higher ΔKHN than the DHEMA0.6 group, which obtained a higher rate of polymerization (p < 0.050). There was no statistical difference in radiopacity and film thickness (p > 0.050). Dual-cured cements with N-(2-hydroxyethyl)acrylamide showed higher color change than methacrylates. Immediate mechanical properties were lower for acrylamide groups (p < 0.050), with higher hydrolytic stability. ConclusionsThe addition of N-(2-hydroxyethyl)acrylamide negatively affected the properties of the dual-cured resin cements. LHEAA1 did not differ in physicochemical and optical properties from the control, with higher hydrolytic stability. Clinical significanceThe results of the study indicate that acrylamides increased mechanical properties over time independently of the curing system mode, with more hydrolytic stability. The clinical performance of experimental resin cements should be evaluated.

In vitro analysis of dental ceramics: evaluation of the radiopacity and chemical composition by raman spectroscopy

Objective: This study compared the radiopacity of different ceramic systems by means of digital radiographs and evaluate the chemical composition of the samples by Raman spectroscopy. Material and Methods: The hypothesis tested was that there was a difference in radiopacity among the tested materials. Specimens were prepared for each ceramic tested: FLD - VM7 (VITA Zahnfabrik), LD - IPS Empress e.max Press (IPS Empress), AL - In Ceram Alumina (VITA Zahnfabrik), ALYZ - In Ceram Zirconia (VITA Zahnfabrik), YZ - Lava All Ceram (3M/ESPE), and MYZ - Zirconzahn (Talladium Brazil). The specimens were radiographed and submitted to radiographic density readings using a histogram tool. The spectrometer coupled to a petrographic microscope was used for Raman spectroscopy measurements. Analysis of variance (ANOVA) and a Tukey post-hoc test were used to compare radiopacity of the different materials. Results: For all tested materials, the radiopacity showed statistically significant differences, except YZ and MYZ. Lava All Ceram and ZirkonZahn had high radiopacity values and VM7 and IPS Empress e.max Press showed lower radiopacity than human dental structures. Conclusion: It was possible to conclude that radiopacity is closely linked to ceramic chemical composition.KeywordsDental ceramics; Radiopacity; Raman spectroscopy test; Restorative dentistry.

Assessing the Radiopacity of Three Resin Composite Materials Using a Digital Radiography Technique

Background: Radiopacity is one of the prerequisites for dental materials, especially for composite restorations. It's essential for easy detection of secondary dental caries as well as observation of the radiographic interface between the materials and tooth structure. The aim of this study to assess the difference in radiopacity of different resin composites using a digital x-ray system. Materials and methods: Ten specimens (6mm diameter and 1mm thickness) of three types of composite resins (Evetric, Estelite Sigma Quick,and G-aenial) were fabricated using Teflon mold. The radiopacity was assessed using dental radiography equipment in combination with a phosphor plate digital system and a grey scale value aluminum step wedge with thickness varying from 1mm to 10mm in steps of 1mm each. The tested materials were radiographed, we used Image J software, on a computer screen to evaluate the degree of radiopacity for each individual material and compare with the aluminum step wedge. Radiopacity was expressed in mm of equivalent aluminum step wedge. Analysis of varience (ANOVA) and Least Significant Difference (LSD) were used to investigate the significance of differences among the tested groups. Results: Statistical analysis showed highly significant difference among the tested groups (p≤0.01). Amongst, G-aenial composite shows the most radiopaque and it is above or equivalent to that of enamel, while Estelite Sigma Quick composite has the lowest radiopacity value and is equivalent to that of dentin. Conclusion: In line with previous studies, and within the limitation of our study, considerable variations in radiopacity values were found among materials depending on the radiopaque elements incorporated into the matrix. All composite materials tested complied with the ISO 4049 standard.

Effects of shade and composition on radiopacity of dental composite restorative materials

The aim of this study was to evaluate the effects of the shade and composition of five dental composite resins on their radiopacity. Five composite resins in various shades were used in this study. Composite specimens were prepared in triplicate for each material and shade using Teflon ring molds. In addition, 1-mm-thick enamel and dentin specimens were prepared from freshly extracted premolar teeth. Each specimen was placed on a dental film together with an aluminum step-wedge to establish radiopacity equivalents for the composite materials, dentin, and enamel. Dental films were exposed using a dental X-ray machine at 70 kVp and 8 mA, and processed using an automatic processor. The optical densities of the composite specimens, step-wedge, enamel, and dentin were evaluated using a densitometer. The data were analyzed by one-way and two-way ANOVA and a post hoc Tukey HSD test at a significance level of a = 0.05. The shades of the tested composite resins did not affect their radiopacity level (p > 0.05). The composition of fillers of the tested composite resins influenced their ability to absorb X-ray radiation. All shades of the tested composite resins met the ISO requirement for radiopacity of resin-based restorative materials. The tested shades of the composite resins were appropriate for dental restorations regarding their radiopacity level. Although there were significant differences in radiopacity among the tested composites, they may not have clinical significance.

Evaluation of the Radiopacity of Esthetic Root Canal Posts

The radiopacity of esthetic root canal posts may impair the assessment of their fit to the root canal when using radiographic images. This study determined in vitro the radiographic density of esthetic root canal posts using digital images. Thirty-six roots of human maxillary canines were assigned to six groups (N=6 per group): Reforpost (RP); Aestheti-Plus (AP); Reforpost MIX (RPM); D.T. Light Post (LP); Reforpost Radiopaque (RPR); and White Post DC (WP). Standardized digital images of the posts were obtained in different conditions: outside the root canal, inside the canal before and after cementation using luting material, and with a tissue simulator. Analysis of variance was used to compare the radiopacity mean values among the posts outside the root canal and among the posts under the other conditions, and the "t" unpaired test to compare the radiopacity between the posts and the dentin, and between the posts and the root canal space. There was no statistically significant difference in radiopacity between RP and RPM, and LP and WP. AP posts showed radiopacity values significantly lower than those for dentin. No statistically significant difference was found between posts (RP and AP) and the root canal space. A statistically significant difference was observed between the luted and non-luted posts; additionally, luted posts with and without tissue simulator showed no significant differences. Most of the cement-luted posts analyzed in this study were distinguishable from the density of adjacent dentin surfaces, allowing radiographic confirmation of the fit of the post in the canal. The success of using esthetic root canal posts depends mainly on the fit of the post within the canal.[1] The radiopacity of a post allows for radiographic imaging to be used to determine the fit, an important factor in a clinical perspective.

In vitro radiographic density of dental posts measured by digital radiography

This study evaluated the radiopacity of seven commercial root canal posts. Digital radiographs of the seven commercial posts and of the same commercial posts and four artificial aluminum posts inserted in lower canines were obtained with a CCD-based digital sensor. The radiopacity of the posts was expressed as mm aluminum/mm material (mmAl). Subsequently, the radiographs were presented to five trained evaluators who were asked to rank their acceptability scores as not acceptable, acceptable, or excellent. Analysis of variance revealed significant differences in radiopacity among the posts (P < 0.05). The radiopacities of zirconium and titanium posts were significantly higher than those of fiber posts (P < 0.05). The minimum aluminum thickness for acceptance in the root canals was 1.2 mmAl. All of the examined posts presented satisfactory radiopacity for clinical application.

Evaluation of the Radiopacity of Luting Cements by Digital Radiography

The aim of this study was to evaluate the radiopacity of eight contemporary luting cements using direct digital radiography. Ten specimens, (5 mm diameter, 1 mm high) were prepared for each material tested (RelyX ARC, RelyX U100, RelyX Unicem, Nexus 2, Nexus 3, Metacem, Breeze, Adhesor zinc phosphate). The specimens were stored in a moist chamber at 37°C until completely set, then radiographed using a Kodak digital sensor and an aluminum step wedge with variable thicknesses (1 to 13 mm in 1-mm increments) used for reference. A Kodak 2100 intraoral X-ray unit was operated at 60 kV, 7 mA, and 0.20 seconds. According to international standards, the radiopacity of the specimens was compared with that of the aluminum step wedge using the equal-density area tool of the Kodak Dental Imaging software (ver. 6.7). Data were analyzed by ANOVA and Tukey's test. Adhesor zinc phosphate cement showed the highest radiopacity of all materials and dentin. Breeze showed the lowest radiopacity (p < 0.05). No significant difference in radiopacity was observed between dentin and RelyX ARC, Nexus 2, or Metacem (p > 0.05). The radiopacities of Nexus 3 and RelyX Unicem were significantly higher than those of other resin cements and dentin (p < 0.05). All materials showed radiopacity above the minimum recommended by the International Organization for Standardization and the American National Standards/American Dental Association. Breeze had less radiopacity than dentin.

Effect of exposure parameters on the radiopacity of root canal sealers

BackgroundThe aim of this study was to test the effect of different kilovoltage, milliampere, and exposure time settings on the radiopacity of two endodontic sealers using an image plate system. Materials and methodsMM-Seal (MicroMega, Besancon, France) and Diaket (3M Espe, Seefeld, Germany) were packed into a polytetrafluoroethylene ring mold with an internal diameter of 10mm and a depth of 1mm. Five discs of each material were imaged alongside an aluminum step-wedge. Sets of radiographs were obtained using storage phosphor plates (SPPs). The SPPs were exposed at 60, 65, or 70kVp, 7 or 8mA for 0.12 or 0.16s. Radiographic densities of the sealers and each step of the step-wedge were analyzed with Image Tool 3.0 SDK software (University of Texas Health Sciences Center, TX, USA). Three readings were made for each image. The mean was calculated to give the radiographic density expressed as mean gray values. Three-way ANOVA was used to test the differences in radiopacity of sealers with respect to kilovoltage, milliampere, exposure time, and the interaction of the three factors. ResultsNo significant difference in sealers’ radiopacity was found with change in three exposure parameters (p>0.05). However, standard deviations of the measurements for lower exposures were greater; MM-Seal was significantly more radiopaque than Diaket (p<0.0001) at any parameter. ConclusionsDifferences in kilovoltage, milliampere, and exposure time do not affect the radiopacity measurements of sealers on SPP images. However, choosing the proper exposure parameters may optimize the gray value range of the sealers allowing for better discrimination of the sealer and surrounding structures thereby providing better clinical guidance.

Comparative radiopacity of ceramics and metals with human and bovine dental tissues

Ceramics should be radiopaque enough to be seen on radiographs and to be distinguishable from tooth structures. Information on the radiopacity of different ceramics used in restorative dentistry is limited. The purpose of this study was to investigate the radiopacity of ceramics in comparison with human and bovine dental hard tissues and metals. A total of 128 disk-shaped specimens, 6 × 1 mm (n=8), were prepared from dental ceramic materials and metals. The optical densities of each material, along with 2 tooth sections (canine and molar teeth), bovine dentin and enamel specimens, and 2 different aluminum step wedges, were measured from radiographic images using a transmission densitometer. The optical densities of the specimens were used to determine the equivalent aluminum thicknesses. The data were analyzed by nonparametric 1-way ANOVA (Kruskal-Wallis) and Student-Newman-Keuls multiple range tests for post hoc comparison (α=.05). Among ceramic materials, Cercon Zirconia had the highest and the Cergo Pressable Ceramic had the lowest radiopacity values. Cergo Pressable Ceramic, Noritake Super Porcelain EX3 dentin, IPS Empress e.max Press, Cercon Kiss dentin, IPS Empress 2, Cercon Ceram dentin, bovine dentin, human canine, and molar tooth dentin radiopacity measurements were not significantly different. The radiopacity measurements of In-Ceram Alumina, In-Ceram Spinell, Celay Alumina, Titanium alloy (Ti-6Al-4V), Celay Zirconia, In-Ceram Zirconia, NiCr alloy, Wieland Zirconia, Cercon Zirconia, and 22-carat gold were significantly higher than that of bovine enamel (P<.05). Significant differences in radiopacity were found among ceramic materials, when compared to metals, bovine enamel and human and bovine dentin. Cercon and Wieland Zirconia had high radiopacity values, which were similar to metals.

Digital analysis of ulnar trochlear notch sclerosis in Labrador retrievers

To compare ulnar trochlear notch bone radiopacity in Labrador retrievers with and without fragmented medial coronoid process using quantitative analysis of film density on digitised radiographs. Mediolateral view elbow radiographs from Labrador retrievers (n=34) aged between six and 18 months were obtained and digitised. Images from dogs with an arthroscopic diagnosis of fragmentation of the medial coronoid process (n=17) were compared with that of a control population (n=17), and this data subject to statistical analysis. A statistically significant relationship between the presence of increased trochlear notch radiopacity and a fragmented medial coronoid process was identified. Fractional analysis of this area shows the region of greatest difference in radiopacity between normal and fragmented medial coronoid process cohorts to be in the trochlear region of the medial coronoid process of the ulna. A decrease in radiopacity values in the dysplastic group versus the normal cohort was observed for the region of the proximo-caudal ulnar trochlear notch. An increase in ulnar trochlear notch radiopacity is a finding associated with fragmentation of the medial coronoid process in Labrador retrievers.

Differential density of normal renal parenchyma on nonenhanced CT: a new observation.

Nonenhanced CT scans through the kidneys commonly show a difference in radiopacity between the inner peripelvic portion of the renal parenchyma and the more peripheral regions of the renal parenchyma. This normal observation has not been described. We reviewed 50 nonenhanced CT scans. Renal parenchyma was evaluated by both visual inspection and density measurements of inner and outer aspects of the kidneys in 38 and visual inspection only in 12. A narrower window was used to better show density differences (100 W, 35 L). We recorded the indication for the CT, history, and recent blood chemistries. The inner parenchyma was of greater radiopacity than the outer parenchyma in 35 of 50 cases by visual inspection and in all densitometry cases (38 of 38). There was no correlation with clinical history or blood chemistry. A difference in density between the inner and outer portions of the renal parenchyma is very common and will often be seen if one looks for it. We have not shown an etiology for this difference, and indeed, it may be physiological. One must be aware of this finding to avoid mistaking it for pathology.

Radiopacity of posterior composite resins, composite resin luting cements, and glass ionomer lining cements

The radiopacities of seven posterior composite resins, seven composite resin luting cements, and six glass ionomer lining cements were studied. The purpose was to obtain an indication of radiopacity values of different brands within each of these three groups of materials and to show differences in radiopacities of composite resin inlay materials and their accompanying luting cements. On radiographs, the optical densities of standardized samples were determined and radiopacity values of the materials were expressed in millimeter equivalent aluminum. The composite resins observed displayed higher radiopacities than aluminum. A luting cement and a glass ionomer cement were shown to be less radiopaque than aluminum. Generally the radiopacity of composite resins appeared to be higher than their accompanying luting cements. If materials with substantial differences in radiopacity are used in combined applications for the restorative treatment of teeth, lower radiopacity can interfere with the diagnosis of caries and the detection of gaps near the restoration.