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Compendium of Continuing Education in... May 2017With the overwhelming acceptance of lithium disilicate and zirconia, the frequency with which dentists have to remove these materials is increasing, and this can be...
With the overwhelming acceptance of lithium disilicate and zirconia, the frequency with which dentists have to remove these materials is increasing, and this can be difficult. Proper cement usage for full-coverage crowns with preparations that have retention and resistance can be helpful if in the future the restoration needs to be removed. When removing these modern materials, bur and laser techniques are both effective means, with each having specific benefits. Materials selection and preparation design are vital when considering areas of risk each patient exhibits and the potential need for removal.
Topics: Ceramics; Crowns; Dental Cements; Dental Materials; Dental Porcelain; Dental Restoration Failure; Humans; Lasers; Zirconium
PubMed: 28459251
DOI: No ID Found -
The International Journal of... 2015This systematic review aimed to identify different prosthodontic outcomes between screw- and cement-retained implant prostheses. (Review)
Review
PURPOSE
This systematic review aimed to identify different prosthodontic outcomes between screw- and cement-retained implant prostheses.
MATERIALS AND METHODS
The relevant articles were retrieved from the following electronic databases: MEDLINE, EMBASE, PubMed (using medical subject headings), and the Cochrane Central Register of Controlled Trials (CENTRAL). The search was performed up to December 31, 2013, and was restricted to studies on human subjects reported in English. A further search was conducted through the reference lists of the articles found as well as from early online articles. Reviewed studies were those on fixed implant prostheses using different retention mechanisms such as screws or cement. Information on types of screws and mechanisms of preloading, as well as different luting cements, was collected in correlation with prosthodontic maintenance/complication issues seen in the clinical studies.
RESULTS
Sixty-two papers met the review criteria. There were only six randomized controlled trials and none of them included an equivalent number of screw- and cement-retained single implant crowns for comparison. Studies used different types of screws and only a few reported the preloading procedure for the prosthetic screws. Other studies involving cement-retained implant prostheses used a range of dental cements; however, some did not specify the type used. Studies reported various prosthodontic maintenance/complication issues such as screw loosening, porcelain fracture, loss of retention, and esthetic concerns. Five studies did not report any prosthodontic maintenance issues during their observation periods. More recent studies also did not report any incidence of screw loosening. Only two studies stated the standardized criteria for reporting their prosthodontic maintenance/ complication issues.
CONCLUSIONS
With inadequate information and various study designs, it was difficult to compare the prosthodontic outcomes between screw and cement-retained fixed implant prostheses. Both retention mechanisms showed prosthodontic maintenance/complication issues that must be considered and this review showed that the introduction of newer implant components may assist in minimizing these issues. It is also recommended that standardized criteria be used when reporting prosthodontic maintenance/complication issues to allow better comparison of data.
Topics: Cementation; Crowns; Dental Cements; Dental Implants, Single-Tooth; Dental Prosthesis Retention; Dental Prosthesis, Implant-Supported; Dental Restoration Failure; Humans
PubMed: 25822297
DOI: 10.11607/ijp.3947 -
American Journal of Dentistry Oct 2023To evaluate the capacity of highly opaque cements on masking titanium abutment background.
PURPOSE
To evaluate the capacity of highly opaque cements on masking titanium abutment background.
METHODS
Dentin and titanium specimens were used to simulate respectively, a natural dental background and an implant abutment. To simulate the full-crowns, Y-TZP zirconia (ZC), lithium disilicate (LD), and resin composite (RC) blocks were used. The titanium specimens were divided into six cementation groups (n=10): two regular cements (BQM and RX); three opaque cements (MHA; VA and BHA); and a clear liquid (CL). The masking capacity of each cement was calculated as the color difference between the color of the crowns over dentin with clear liquid (reference) and the color of the crowns over the titanium with the different cements (ΔEab). Data were statistically analyzed using two-way ANOVA and Tukey test (α= 0.05).
RESULTS
Significant differences (P= 0.0001) were observed for both factors, cement and crown, and for the interactions between them. The results of Tukey test for cement were: BHA-2.25(0.98), MHA-2.94 (1.03), VA-3.45 (1.67), BQM-9.55 (2.77), RX-9.88 (3.12), CL-10.41 (3.47). The cements BHA, MHA and VA showed significantly smaller means than BQM, RX and CL. The results for crown were: ZC-3.66 (2.37), LD-7.50 (4.08), RC-8.08 (4.67). The means for all crown materials were significantly different. Highly opaque cements were more efficient on background masking than regular cements. Zirconia promoted the higher color masking while the resin composite the lowest.
CLINICAL SIGNIFICANCE
The use of a highly opaque cement can reduce the color interference of the titanium abutment background, favoring the esthetic outcome of metal-free cemented crowns.
Topics: Composite Resins; Crowns; Dental Abutments; Dental Cements; Dental Porcelain; Glass Ionomer Cements; Materials Testing; Resin Cements; Titanium; Zirconium
PubMed: 37865808
DOI: No ID Found -
Journal of the Mechanical Behavior of... Jun 2023Cariogenic bacteria and dental plaque biofilm at prosthesis margins are considered a primary risk factor for failed restorations. Resin cement containing antibacterial...
Cariogenic bacteria and dental plaque biofilm at prosthesis margins are considered a primary risk factor for failed restorations. Resin cement containing antibacterial agents can be beneficial in controlling bacteria and biofilm. This work aimed to evaluate the impact of incorporating magnesium oxide nanoparticles (MgONPs) as an antibacterial filler into dual-cure resin cement on bacteriostatic activity and physical properties, including mechanical, bonding, and physicochemical properties, as well as performance when subjected to a 5000-times thermocycling regimen. Experimental resin cements containing MgONPs of different mass fractions (0, 2.5%, 5%, 7.5% and 10%) were developed. Results suggested that the inclusion of MgONPs markedly improved the materials' bacteriostatic effect against Streptococcus mutans without compromising the physical properties when its addition reached 7.5 wt%. The mechanical properties of the specimens did not significantly decline after undergoing aging treatment, except for the flexural properties. In addition, the cements displayed good bonding performance and the material itself was not prone to cohesive fracture in the failure mode analysis. Furthermore, MgONPs possibly have played a role in decelerating material aging during thermocycling and enhancing bonding fastness in the early stage of cementation, which requires further investigation. Overall, developing MgONPs-doped resin cements can be a promising strategy to improve the material's performance in inhibiting cariogenic bacteria at restoration margins, in order to achieve a reduction in biofilm-associated secondary caries and a prolonged restoration lifespan.
Topics: Resin Cements; Magnesium Oxide; Materials Testing; Anti-Bacterial Agents; Nanoparticles; Dental Cements; Dental Bonding
PubMed: 37068430
DOI: 10.1016/j.jmbbm.2023.105815 -
The Journal of Prosthetic Dentistry May 2021Automixing and dispensing cements is a straightforward approach with consistent dosing. Previous studies have demonstrated clinically significant differences in crown...
STATEMENT OF PROBLEM
Automixing and dispensing cements is a straightforward approach with consistent dosing. Previous studies have demonstrated clinically significant differences in crown retention between power-liquid and paste-paste forms of the same cement, as the composition between the 2 differs. A self-adhesive modified-resin (SAMR) and a resin-modified glass ionomer (RMGI) cement, originally offered as a powder-liquid, are now in common use as paste-paste automixed cements. With the increased use of zirconia restorations, the long-term retention of zirconia crowns for these 2 automixed cements should be evaluated.
PURPOSE
The purpose of this in vitro study was to determine whether zirconia crowns cemented with 2 automixed cements provided clinically acceptable retention after 6 months of aging with monthly thermocycling.
MATERIAL AND METHODS
Extracted molars were mounted in resin and prepared with a flat occlusal surface, 20-degree taper, approximately 4-mm axial length, and with the axio-occlusal line angle slightly rounded. Prepared teeth were equally distributed into 3 cementation groups (n=12) to achieve nearly equal mean preparation surface areas for each group. Zirconia crowns (IPS ZirCAD LT) were fabricated with an added occlusal bar to facilitate removal of the cemented crowns. Cement space was set at 45 μm axially and 55 μm occlusally. After sintering and before delivery, the intaglio surfaces were airborne-particle abraded with 50-μm alumina at 275-kPa pressure for 3 seconds and then steam cleaned. Cements were the original powder-liquid RelyX Luting (RMGI; RXL) as the control, paste-paste, automixed systems RelyX Luting Plus Automix (RMGI; RXLA), and RelyX Unicem 2 Automix (SAMR; RXUA). Crowns were cemented under 196 N force, placed in an oven at 37 °C and 100% humidity during setting and then thermocycled (5 °C-55 °C) for 5000 cycles monthly for 6 months. The crowns were removed axially with a universal testing machine at 0.5 mm/min. Removal forces were recorded and dislodgement stress calculated by using the surface area of each preparation. One-way ANOVA was used for dislodgement stress and force. Chi-square test was used for cement location after testing (α=.05).
RESULTS
RXLA demonstrated considerably lower crown retention (1.3 MPa) and differed significantly (P<.001) from RXUA (3.1 MPa) and RXL (3.1 MPa). Modes of failure showed most of the cement remaining only in the crown intaglio for RXLA for all specimens, whereas half of the crowns for RXL and RXUA demonstrated cement adhesion to both dentin and the intaglio surface, indicating cohesive failure of the cement at separation. As the Levene test was significant, the Games-Howell test was used for mean differences. The χ analysis was significant.
CONCLUSIONS
After long-term aging with monthly thermocycling, high-strength zirconia crowns were strongly retained by 2 (RXL, RXUA) of the 3 cements. Crown retention for RelyX Luting Plus Automix was less than half in comparison and with cement found only on the intaglio surface after separation.
Topics: Crowns; Dental Cements; Dental Prosthesis Retention; Dental Stress Analysis; Glass Ionomer Cements; Materials Testing; Resin Cements; Zirconium
PubMed: 32669207
DOI: 10.1016/j.prosdent.2020.04.014 -
Journal of the American Dental... Jun 2023Opaque cements can be esthetically unfavorable and alternative translucent materials have been developed. The aim of this study was to evaluate the color interference of...
BACKGROUND
Opaque cements can be esthetically unfavorable and alternative translucent materials have been developed. The aim of this study was to evaluate the color interference of a new translucent cement compared with conventional materials, in association with interim restoration with different thickness and shades.
METHODS
Bis-acryl composite disks were prepared in 2 thicknesses (1.2 mm, 0.6 mm) and 3 shades (A3.5, A2, bleached) to simulate the restorations. Cementation over dentin disks was performed with 1 translucent cement (Provicol QM Aesthetic; VOCO), 2 conventional cements (Provicol; VOCO, Temp-Bond NE; Kerr Dental), and 1 transparent liquid (polyethylene glycol 400). The difference between the color of the specimens cemented with the transparent liquid and that of the specimens cemented with each cement was calculated (ΔEab). The data were analyzed using 3-way analysis of variance and Tukey tests (5%).
RESULTS
Significant differences were observed for all factors and some interactions (P < .05). For Provicol QM Aesthetic, the shade and thickness did not influence the ΔEab. For Provicol and Temp-Bond NE, the lighter and thinner the specimen, the higher the ΔEab. Only Provicol QM Aesthetic had smaller means than the perceptibility threshold. Temp-Bond NE and Provicol had higher values than the acceptability threshold for some combinations.
CONCLUSIONS
The highly translucent cement had less color interference than the conventional materials. The thickness and resin shade only affected the results for the opaque cements. The thinner specimens and the lighter shades had higher color interference.
PRACTICAL IMPLICATIONS
The use of a more translucent cement can produce a smaller color interference on the esthetic outcome of interim restorations.
Topics: Humans; Dental Porcelain; Resin Cements; Esthetics, Dental; Dental Cements; Glass Ionomer Cements; Color; Materials Testing; Surface Properties; Ceramics
PubMed: 37115140
DOI: 10.1016/j.adaj.2023.03.010 -
General Dentistry 2022Limited research has been published evaluating the failure of zirconia crowns with less retentive tooth preparations. The purpose of this study was to evaluate the...
Limited research has been published evaluating the failure of zirconia crowns with less retentive tooth preparations. The purpose of this study was to evaluate the effect of axial wall height (AWH) and cement type on the fracture load of cubic phase-containing zirconia crowns. Standardized crown preparations with an AWH of 0, 2, or 4 mm (n = 10) were made in 90 extracted human maxillary third molars. The preparations were scanned, and crown restorations were designed. Cubic phase-containing zirconia crowns were milled and cemented with a resin-modified glass ionomer cement, a self-adhesive resin cement, or an adhesive resin cement. The specimens were subjected to thermocycling and cyclic loading. Each crown specimen was positioned in a universal testing machine so that the long axis of the tooth was at a 60° angle to the testing fixture and loaded until failure using a stainless steel rod resting on the buccal incline of the palatal cusp. Data were found to have a nonnormal distribution and were analyzed with Kruskal-Wallis and Mann-Whitney U tests (α = 0.05). Statistically significant differences in the median fracture loads of the groups were found based on both AWH and cement type (P < 0.05). Regardless of cement type, the median fracture loads were significantly lower in the 0-mm AWH groups than in the 2-mm and 4-mm AWH groups, which were not significantly different from each other. Compared to the other cement types, adhesive resin cement resulted in a significantly greater median fracture load when the AWH was 0 mm. The use of an adhesive resin cement with a cubic phase-containing zirconia crown may provide greater fracture resistance for preparations with minimal AWH.
Topics: Crowns; Dental Cements; Dental Materials; Dental Prosthesis Design; Dental Restoration Failure; Dental Stress Analysis; Glass Ionomer Cements; Humans; Materials Testing; Resin Cements; Zirconium
PubMed: 35993929
DOI: No ID Found -
American Journal of Dentistry Feb 2023To evaluate the effect of material type, material thickness and cement shade on the final color of two different ceramic/glass-polymer-based CAD-CAM blocks over colored...
PURPOSE
To evaluate the effect of material type, material thickness and cement shade on the final color of two different ceramic/glass-polymer-based CAD-CAM blocks over colored abutments.
METHODS
Tested blocks (Vita Enamic-VE and Cerasmart-Cs) were cut in three different thicknesses (1, 1.5 and 2 mm), and cemented on two different shaded (B1 and C3) resin discs with three shades (A2-Universal, W-White, T-Translucent) of a self-adhesive resin cement. An additional 10 specimens were prepared for control (n= 370). 36 subgroups were formed to simulate different clinical conditions (n= 10). The final color difference (ΔE₀₀) was recorded as the difference between material-cement-resin composite assembly and control specimens on a black background according to the CIEΔE 2000 color difference formula. Clinical perceptibility (0.80) and acceptability thresholds (1.80) were used to evaluate the results. Data were analyzed using the Kruskal-Wallis and the Mann-Whitney U non-parametric tests at P< 0.05 significance level.
RESULTS
ΔE₀₀ results were influenced by the polymer-based CAD-CAM material type, material thickness, and cement shade (P< 0.05) over both abutment shades. VE exhibited lower ΔE₀₀ values than Cs over B1 and C3 shaded abutments (for each abutment P< 0.001). Specimens of 1 mm thickness exhibited significantly higher ΔE₀₀ than the 2 mm or 1.5 mm specimens (P< 0.001), and W cement shade demonstrated higher ΔE₀₀ than T or A2 shades (P< 0.001) over both shaded abutments.
CLINICAL SIGNIFICANCE
The final color of the polymer-based CAD-CAM restoration can be improved by the suitable combination of material/material thickness/cement shade to achieve the desired esthetic outcomes within clinically acceptable limits. Regardless of the type of polymer-based CAD-CAM material chosen, at least 1.5 mm restoration thickness with the use of Translucent or A2 cement shade is recommended for masking whitened or darkened shaded abutment teeth in clinical practice.
Topics: Dental Porcelain; Polymers; Color; Ceramics; Dental Cements; Resin Cements; Glass Ionomer Cements; Computer-Aided Design; Materials Testing; Surface Properties
PubMed: 36917709
DOI: No ID Found -
Journal of Dentistry Dec 2015White spot lesions are the most undesired side-effect of fixed orthodontic treatments. The objectives of this study were to combine nanoparticles of silver (NAg) with...
OBJECTIVES
White spot lesions are the most undesired side-effect of fixed orthodontic treatments. The objectives of this study were to combine nanoparticles of silver (NAg) with 2-methacryloyloxyethyl phosphorylcholine (MPC) to develop a modified resin-modified glass ionomer cement (RMGI) as orthodontic cement with double benefits of antibacterial and protein-repellent capabilities for the first time.
METHODS
NAg and MPC were incorporated into a commercial RMGI. Another commercial orthodontic adhesive also served as control. Enamel shear bond strengths (SBS) were determined. Protein adsorption was measured via a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was tested. Biofilms adherent on the cement samples and planktonic bacteria in the culture medium away from the cement surfaces were both evaluated for bacterial metabolic activity, colony-forming units (CFU), and lactic acid production.
RESULTS
Adding 0.1% NAg and 3% MPC to RMGI, and water-aging for 30 days, did not adversely affect the SBS, compared to the unmodified RMGI control (p>0.1). The modified RMGI containing 0.1% NAg and 3% MPC achieved the greatest reduction in protein adsorption, bacterial adhesion, CFU, metabolic activity and lactic acid production. The RMGI containing 0.1% NAg and 3% MPC inhibited not only the bacteria on its surface, but also the bacteria away from the surface in the culture medium.
CONCLUSIONS
The incorporation of double agents (antibacterial NAg+protein-repellent MPC) into RMGI achieved much stronger inhibition of biofilms than using each agent alone. The novel antibacterial and protein-repellent RMGI with substantially-reduced biofilm acids is promising as an orthodontic cement to combat white spot lesions in enamel.
Topics: Anti-Bacterial Agents; Bacteria; Bacterial Adhesion; Biofilms; Dental Bonding; Dental Caries; Dental Cements; Dental Enamel; Dental Plaque; Glass Ionomer Cements; Humans; Lactic Acid; Metal Nanoparticles; Methacrylates; Phosphorylcholine; Random Allocation; Saliva; Silver; Water
PubMed: 26427311
DOI: 10.1016/j.jdent.2015.09.006 -
Journal of Prosthodontics : Official... Jun 2023To assess the fracture resistance of monolithic zirconia crowns cemented with different types of cement on cement-retained implant abutments.
PURPOSE
To assess the fracture resistance of monolithic zirconia crowns cemented with different types of cement on cement-retained implant abutments.
MATERIALS AND METHODS
Forty implant analogs were positioned in acrylic resin blocks, and cement-retained straight implant abutments were fastened to the analogs. Crowns were designed with/without occlusal vent holes and produced from monolithic zirconia blocks by the CAD-CAM technique. The two crown types were divided into two groups and cemented with resin and zinc-polycarboxylate cement under 5 kg weight. A universal testing machine applied compressive forces to the crowns until fracture. Fracture resistance values were analyzed using two-way ANOVA and the independent samples t-test with statistical significance set at p < 0.05.
RESULTS
According to the two-way ANOVA results, although the crown design did not have a significant effect on fracture resistance (1417.65 ± 337.39 N, 1565.16 ± 517.12 N; crowns with and without vent holes, respectively), the main effect of the cement variable on the fracture resistance was significant. Zinc-polycarboxylate cement (1680.1 ± 375.23 N) showed higher fracture resistance than resin cement (1302.71 ± 420.64 N) in the crowns designed with vent holes (p < 0.005).
CONCLUSION
The use of cement-retained implant-supported monolithic zirconia crowns with an occlusal vent hole is safe, and zinc-polycarboxylate cement use may be an appropriate choice for cementation of these crowns.
Topics: Polycarboxylate Cement; Dental Abutments; Dental Cements; Crowns; Glass Ionomer Cements; Zirconium; Computer-Aided Design; Materials Testing; Zinc; Dental Stress Analysis
PubMed: 35752941
DOI: 10.1111/jopr.13563