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International Journal of Computerized... Nov 2023The aim of the present study was to evaluate the effect of cement gap and drill offset on the marginal and internal fit discrepancies of crowns designed with different...
AIM
The aim of the present study was to evaluate the effect of cement gap and drill offset on the marginal and internal fit discrepancies of crowns designed with different tooth preparations.
MATERIALS AND METHODS
Five tooth preparations were constructed, and crowns with different cement gaps and drill offsets were obtained. Then, best-fit alignment was performed on the crowns with the corresponding tooth preparations, and the fit discrepancies were expressed by color-coded difference images and root mean square (RMS) values. The RMS values of each group were analyzed by the rank-based Scheirer-Ray-Hare test (α = 0.05).
RESULTS
The color segments in the sharp line angles area of the Sharp line angles group changed significantly before and after the drill offset. The cement gap had a significant effect on the marginal, internal, or overall fit discrepancies of the five design groups (P < 0.001), while the drill offset had a significant effect on the marginal fit discrepancies of the Shoulder-lip group and the internal or overall fit discrepancies of the Sharp line angles group (P < 0.001). Additionally, the interaction effect between cement gap and drill offset was significant for the marginal fit discrepancies of the Shoulder-lip group and the internal or overall fit discrepancies of the Sharp line angles group (P < 0.01).
CONCLUSIONS
The cement gap and drill offset had a significant adverse effect on the marginal or internal fit discrepancies of the crowns designed with the shoulder-lip and sharp line angles designs. Tooth preparation designs with intense curvature changes such as shoulder-lip and sharp line angles should be avoided clinically.
Topics: Humans; Dental Cements; Crowns; Glass Ionomer Cements; Tooth Preparation; Tooth Preparation, Prosthodontic; Dental Prosthesis Design; Computer-Aided Design; Dental Marginal Adaptation; Dental Porcelain
PubMed: 36749283
DOI: 10.3290/j.ijcd.b3839037 -
The Journal of Prosthetic Dentistry Oct 2022Although the 2D analysis of prosthesis cementation space has been popular, its correlation with volumetric comparison (3D data) of cement space is unclear.
STATEMENT OF PROBLEM
Although the 2D analysis of prosthesis cementation space has been popular, its correlation with volumetric comparison (3D data) of cement space is unclear.
PURPOSE
The purpose of this in vitro study was to evaluate the cement space in computer-aided design and computer-aided manufacturing (CAD-CAM) crowns of different materials and correlate 2D measurements of cement space with their corresponding 3D values (volume of cement space) by using microcomputed tomography (μCT) analysis of regions of interest.
MATERIAL AND METHODS
Ten molar crowns were milled in lithium disilicate (LD), resin nanoceramic (RN), and zirconia (Z) ceramics. Silicone replicas were produced and used as the analog cement layer and scanned with a desktop X-ray microfocus CT scanner. Twenty-eight slices were evaluated in 3 regions: marginal, axial, and occlusal (n=84 measurement points/specimen). After 3D reconstruction of the cement space, the volume was calculated. Data were statistically evaluated through 2-way ANOVA and Bonferroni test (α=.05). The Pearson correlation test was used to investigate the correlation between the 2D and 3D data.
RESULTS
The volumes of the occlusal (LD 10 ±1 mm; RN 9 ±1 mm) and axial regions (LD 9 ±2 mm; RN 8 ±1 mm) were significantly higher than the volume of the marginal region for LD and RN specimens (LD 6 ±2 mm; RN 4 ±1 mm) (both P<.001). For the Z group, the axial region had the highest volume (19 ±2 mm), followed by the volumes of the occlusal (15 ±1 mm) and marginal regions (12 ±1 mm). The Pearson correlation test determined a moderate positive correlation of the marginal area (r=0.606, P<.001) and of the axial region (r=0.588, P<.001). However, a moderate negative correlation was found between volume and thickness of the occlusal area (r=-0.437, P=.016).
CONCLUSIONS
Z showed more volume of cement space, as well as thicker cement space than LD and RN. The μCT analysis is an efficient method of analyzing cement thickness and volume in ceramic crowns at the selected regions of interest. A moderate positive correlation was found between the 2D and 3D analyses for the axial and marginal regions of ceramic crowns.
Topics: Dental Marginal Adaptation; Dental Prosthesis Design; X-Ray Microtomography; Crowns; Computer-Aided Design; Dental Porcelain; Dental Materials; Ceramics; Dental Cements; Glass Ionomer Cements
PubMed: 33750574
DOI: 10.1016/j.prosdent.2020.08.051 -
The Journal of Prosthetic Dentistry Apr 2021Dental cements that release monomers that negatively impact adjacent oral soft tissues may adversely affect clinical outcomes. However, in vitro studies evaluating the...
STATEMENT OF PROBLEM
Dental cements that release monomers that negatively impact adjacent oral soft tissues may adversely affect clinical outcomes. However, in vitro studies evaluating the cytotoxic and genotoxic potential of substances released from dental cements are lacking.
PURPOSE
The purpose of this in vitro study was to define and compare the cytotoxicity and genotoxicity of the eluates of a self-adhesive resin cement (RelyX Unicem 2 Automix) autopolymerized and light polymerized with 2 other types of luting cements: a glass ionomer cement (Ketac Cem Easymix) and a resin-modified glass ionomer cement (Ketac Cem Plus).
MATERIAL AND METHODS
The eluates were prepared, and 3T3 mouse fibroblast cells were exposed for 24 hours to serial eluate dilutions of the 3 types of cement. Cytotoxicity was determined by using a cell viability assessment through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays. Genotoxic effects were determined by using the cytokinesis-block micronucleus assay.
RESULTS
Cell viability was higher in the presence of the glass ionomer cement eluate than of the resin-modified glass ionomer cement and resin cement eluates. A pronounced decrease in viability was found when the cells were exposed to undiluted samples of resin-modified glass ionomer cement (around 50%) or resin cement (around 80% to 90%). No significant difference in cell viability was found between autopolymerized and light-polymerized resin cements. All cements induced a dose-dependent response of mononucleated cell formation. However, only the resin cements showed double strand breaks significant differences in the deoxyribonucleic acid (DNA) molecules against the basal DNA lesions that occurred spontaneously.
CONCLUSIONS
The glass ionomer cement was not found to be cytotoxic or genotoxic, whereas the eluates derived from the resin-modified glass ionomer cement and resin cement, independently of the polymerization method, were cytotoxic in fibroblast cells. Maximum cytotoxicity was observed in the presence of resin cement, which also showed genotoxicity, independently of being light polymerized.
Topics: Animals; Composite Resins; Dental Cements; Fibroblasts; Glass Ionomer Cements; Materials Testing; Mice; Resin Cements
PubMed: 33597080
DOI: 10.1016/j.prosdent.2021.01.002 -
The Journal of Prosthetic Dentistry May 2022Screw- and cement-retained prostheses (SCRPs) may be contaminated during fabrication in a dental laboratory, leading to mechanical and biological complications related... (Randomized Controlled Trial)
Randomized Controlled Trial
STATEMENT OF PROBLEM
Screw- and cement-retained prostheses (SCRPs) may be contaminated during fabrication in a dental laboratory, leading to mechanical and biological complications related to the implant treatment. Studies that explored methods to efficiently and conveniently clean and disinfect SCRPs are sparse.
PURPOSE
The purpose of this clinical study was to compare the efficiency of 3 methods to remove contaminants and microorganisms present on the surface of an SCRP.
MATERIAL AND METHODS
Forty-eight 1-unit SCRPs fabricated in a dental laboratory were randomly divided into 3 groups: wiping, soaking, or ultrasonic cleaning. The presence of contaminants was determined by scanning electron microscopy, and microbial cells were cultured before and after treatment. Bacterial colony-forming units (CFUs) on the surface of the SCRPs and contamination density at the implant-abutment interface and emergence profile area were assessed. Statistical tests including ANCOVA were used to compare the efficiency of different methods before and after treatment (α=.05).
RESULTS
Significant differences in contamination density were noted during the treatment at the implant-abutment interface and at the emergence profile area in the 3 groups (P<.05), but no significant differences were observed in the number of CFUs (P>.05). There were significant differences among the 3 methods for cleaning efficiency both at the implant-abutment interface (P=.023) and the emergence profile area (P=.038). At the implant-abutment interface, the contamination density after treatment was lower in the ultrasonic cleaning group than that in the soaking group (P=.007), whereas at the emergence profile area, the contamination density after treatment was lower in the ultrasonic cleaning group than that in the wiping group (P=.019) and the soaking group (P=.048).
CONCLUSIONS
All 3 treatment methods reduced contaminants on the SCRP surface, but ultrasonic cleaning yielded the most favorable results. However, none of the methods provided additional disinfection for SCRPs previously disinfected by ozone and UV in a dental laboratory.
Topics: Bone Screws; Dental Abutments; Dental Cements; Dental Implant-Abutment Design; Dental Implants; Dental Materials; Dental Prosthesis, Implant-Supported; Glass Ionomer Cements; Humans
PubMed: 33454114
DOI: 10.1016/j.prosdent.2020.10.029 -
Influence of inorganic nanoparticles on dental materials' mechanical properties. A narrative review.BMC Oral Health Nov 2023Inorganic nanoparticles have been widely incorporated in conventional dental materials to help in improving their properties. The literature has shown that incorporating... (Review)
Review
Inorganic nanoparticles have been widely incorporated in conventional dental materials to help in improving their properties. The literature has shown that incorporating nanoparticles in dental materials in different specialties could have a positive effect on reinforcing the mechanical properties of those materials; however, there was no consensus on the effectiveness of using nanoparticles in enhancing the mechanical properties of dental materials, due to the variety of the properties of nanoparticles itself and their effect on the mechanical properties. This article attempted to analytically review all the studies that assessed the effect of different types of inorganic nanoparticles on the most commonly used dental materials in dental specialties such as polymethyl methacrylate, glass ionomer cement, resin composite, resin adhesive, orthodontic adhesive, and endodontic sealer. The results had shown that those inorganic nanoparticles demonstrated positive potential in improving those mechanical properties in most of the dental materials studied. That potential was attributed to the ultra-small sizes and unique physical and chemical qualities that those inorganic nanoparticles possess, together with the significant surface area to volume ratio. It was concluded from this comprehensive analysis that while a definitive recommendation cannot be provided due to the variety of nanoparticle types, shapes, and incorporated dental material, the consensus suggests using nanoparticles in low concentrations less than 1% by weight along with a silane coupling agent to minimize agglomeration issues and benefit from their properties.
Topics: Humans; Dental Cements; Dental Bonding; Resin Cements; Composite Resins; Glass Ionomer Cements; Nanoparticles; Materials Testing; Surface Properties; Stress, Mechanical; Dental Materials
PubMed: 37990196
DOI: 10.1186/s12903-023-03652-1 -
Acta Odontologica Latinoamericana : AOL Dec 2021This study evaluated the influence of resin cements and glass ionomers on tensile strength and types of failure of zirconia copings cemented on titanium base abutments....
This study evaluated the influence of resin cements and glass ionomers on tensile strength and types of failure of zirconia copings cemented on titanium base abutments. Forty-two samples were prepared, which were formed by a Cone Morse implant, a titanium abutment with the fixing screw, and a zirconia structure made using a CAD/CAM system. The samples (n = 42) were randomly distributed according to the cementing agent: resin-modified glass ionomer cement (RelyX Luting 2), self-adhesive resin cement (RelyX U200), and self-curing resin cement (Multilink N). After cementation of the copings, half of the samples from each group (n = 7) were randomly selected and subjected to thermocycling (5000 cycles). A tensile load test was performed on a universal testing machine until failure occurred (1 mm). In addition, the type of failure was analyzed using the two-way analysis of variance test and Tukey's post-hoc test (α = 0.05). Lower tensile load was observed for the glass ionomer cement (p < 0.001) regardless of the evaluation period. After thermocycling, a significant reduction in tensile load values was verified for both evaluated cements (p = 0.047). For the resin cements, failures were predominantly of the screw fracture type (82.1%) already with the use of glass ionomer cement, and 28.5% of the failures were of an adhesive type between the zirconia coping and the cement. Resin cements have better stability under tensile load compared to resin glass ionomers when cementing zirconia copings on titanium base abutments.
Topics: Adaptation, Psychological; Cementation; Dental Cements; Dental Prosthesis Retention; Dental Stress Analysis; Glass Ionomer Cements; Materials Testing; Resin Cements; Surface Properties; Zirconium
PubMed: 35088807
DOI: 10.54589/aol.34/3/214 -
BMC Oral Health Aug 2021White spot lesions (WSLs) often occur in orthodontic treatments. The objectives of this study were to develop a novel orthodontic cement using particles of nano silver...
BACKGROUND
White spot lesions (WSLs) often occur in orthodontic treatments. The objectives of this study were to develop a novel orthodontic cement using particles of nano silver (NAg), N-acetylcysteine (NAC) and 2-methacryloyloxyethyl phosphorylcholine (MPC), and to investigate the effects on bonding strength, biofilms and biocompatibility.
METHODS
A commercial resin-modified glass ionomer cement (RMGIC) was modified by adding NAg, NAC and MPC. The unmodified RMGIC served as the control. Enamel bond strength and cytotoxicity of the cements were investigated. The protein repellent behavior of cements was also evaluated. The metabolic assay, lactic acid production assay and colony-forming unit assay of biofilms were used to determine the antibacterial capability of cements.
RESULTS
The new bioactive cement with NAg, NAC and MPC had clinically acceptable bond strength and biocompatibility. Compared to commercial control, the new cement suppressed metabolic activity and lactic acid production of biofilms by 59.03% and 70.02% respectively (p < 0.05), reduced biofilm CFU by 2 logs (p < 0.05) and reduced protein adsorption by 76.87% (p < 0.05).
CONCLUSIONS
The new cement with NAg, NAC and MPC had strong antibacterial capability, protein-repellent ability and acceptable biocompatibility. The new cement is promising to protect enamel from demineralization during orthodontic treatments.
Topics: Anti-Bacterial Agents; Biofilms; Dental Bonding; Dental Cements; Dental Enamel; Glass Ionomer Cements; Humans; Materials Testing; Orthodontic Brackets; Resin Cements
PubMed: 34416896
DOI: 10.1186/s12903-021-01779-7 -
Acta Odontologica Latinoamericana : AOL Aug 2023This study evaluated cytotoxicity and antioxidant gene expression of resin cements on human gingival fibroblasts (hGF).
AIM
This study evaluated cytotoxicity and antioxidant gene expression of resin cements on human gingival fibroblasts (hGF).
MATERIALS AND METHOD
RelyX Ultimate™(RXU), Variolink™II(VLII), and RelyXU200™(RXU200) resin cements were incubated with culture medium for 24 h to obtain eluates. Then, the eluates were applied over hGF to assess cell viability at 24 h, 48 h, and 72 h and antioxidant gene expression at 24 h. hGF cultures non-exposed to the eluates were used as Control. Data were submitted to ANOVA and Bonferroni tests (α≤0.05).
RESULTS
RXU and RXU200 reduced the number of viable cells in 24 h. Longer exposure to cement extracts caused cell death. Gene expression showed peroxiredoxin 1 (PRDX1) induction by all resin cement types, and superoxide dismutase 1 (SOD1) induction by RXU200 and VLII. Moreover, RXU200 induced not only PRDX1 and SOD1, but also glutathione peroxidase 1 (GPX1), catalase (CAT), and glutathione synthetase (GSS).
CONCLUSIONS
All resin cements showed toxicity, and induced antioxidant genes in hGF. Antioxidant gene induction is at least partly associated with cytotoxicity of tested cements to oxidative stress experience.
Topics: Humans; Resin Cements; Antioxidants; Superoxide Dismutase-1; Materials Testing; Dental Cements
PubMed: 37776509
DOI: 10.54589/aol.36/2/ -
Journal of Prosthodontics : Official... Oct 2022To investigate the potential of adding silver-nanoparticle-containing amorphous calcium phosphate microparticles as bioactive fillers into commercially available...
PURPOSE
To investigate the potential of adding silver-nanoparticle-containing amorphous calcium phosphate microparticles as bioactive fillers into commercially available nonbioactive dental resin cement.
MATERIALS AND METHODS
Experimental cement was formulated by adding 7.5% silver-nanoparticle-containing amorphous calcium phosphate microparticles to Multilink Automix resin cement (Ivoclar Vivadent). The experimental cement was evaluated for shear bond strength (N = 11 per group) and demineralization/remineralization (N = 16 per group), with BioCem Universal BioActive cement (NuSmile) as the positive control and Multilink Automix cement as the negative control. One-way analysis of variance and post hoc tests were used to assess the significance of differences among or between the groups RESULTS: The addition of silver-nanoparticle-containing amorphous calcium phosphate microparticles at the level of 7.5% by weight into Multilink Automix did not have a statistically significant effect on the shear bond strength (p > 0.05), but statistically significantly increased the depth of remineralization on both dentin and enamel (p = 0.01 and p < 0.001, respectively) when compared to Multilink Automix alone. The experimental cement prepared in the present study was comparable to BioCem on the depths of remineralization on both dentin and enamel (p = 0.59 and p = 0.99, respectively).
CONCLUSION
When incorporated into nonbioactive commercial dental resin cements as bioactive fillers at the level of 7.5% by weight, silver-nanoparticle-containing amorphous calcium phosphate microparticles could provide remineralization potential without affecting the shear bond strength.
Topics: Resin Cements; Dental Cements; Silver; Materials Testing; Glass Ionomer Cements; Dental Materials; Shear Strength; Dental Bonding; Surface Properties; Dental Stress Analysis
PubMed: 34942682
DOI: 10.1111/jopr.13473 -
Dental Materials : Official Publication... Dec 2022To correlate trueness and cement-space characteristics of crowns milled chairside and in the laboratory with those of inkjet 3D-printed crowns, and to assess whether...
OBJECTIVES
To correlate trueness and cement-space characteristics of crowns milled chairside and in the laboratory with those of inkjet 3D-printed crowns, and to assess whether 3D-printing accuracy meets the clinical standard.
METHODS
Thirty crowns were either (1) milled using a chairside Cerec MCXL unit from Cerec Zirconia Mono L (Dentsply Sirona), (2) milled using a LX-O 5-axis (Matsuura Machinery) industrial machine from Initial Zirconia HT (GC), or (3) 3D-printed using an inkjet Carmel 1400 (Xjet) printer (n = 10). Crown trueness determined by comparing the original CAD with each visible-light digitized crown was correlated with the 3D cement-space characteristics recorded by micro-CT. Statistics involved Kruskal-Wallis testing and Spearman correlation.
RESULTS
Crown trueness at the intaglio marginal area positively correlated with the marginal and axial cement-space characteristics. 3D-printing revealed data in-between those of the two milling systems with undercut values being not statistically different from those recorded for chairside milling and a low overcut level that was statistically similar to that obtained by laboratory milling. Laboratory milling revealed a significantly better marginal accuracy with a consequently lower cement-space thickness. A higher overcut level was recorded for the chairside-milled crowns in the marginal/occlusal thirds, resulting in the significantly highest occlusal cement-space thickness and cement-volume percentage with a cement thickness above 120 µm (limit considered as clinically acceptable). No statistical difference in trueness was found for the external crown dimensions.
SIGNIFICANCE
The 3D-printed zirconia crowns provided sufficient manufacturing accuracy for clinical use. Accurate milling and printing of the crown's intaglio marginal area is primordial.
Topics: Dental Materials; Dental Cementum; Dental Cements; Printing, Three-Dimensional; Glass Ionomer Cements; Bone Cements; Crowns
PubMed: 36411148
DOI: 10.1016/j.dental.2022.11.002