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Cureus Apr 2024In order to effectively address challenges related to anterior teeth restoration and achieve natural-looking results, considerations such as shape, size, gingival...
In order to effectively address challenges related to anterior teeth restoration and achieve natural-looking results, considerations such as shape, size, gingival contour, and color are crucial. Due to an increasing desire for visually appealing alternatives that are free of metal, materials such as dental zirconia have become popular because of their superior aesthetics and mechanical characteristics. This case report presents clinical insights into anterior teeth rehabilitation with the use of layered zirconia fixed dental prostheses. It delves into the experiences associated with zirconia dental restorations on both endodontically treated and vital abutments, aiming to discern how various factors influence treatment outcomes. Beginning with the design of the restoration, its intricacies significantly impact its fit, strength, and overall durability. Moreover, the composition of zirconia used plays a pivotal role, as different formulations offer varying degrees of mechanical properties, influencing factors such as resilience and wear resistance. The shade selection is also scrutinized, as it directly affects the restoration's aesthetic integration with surrounding natural teeth, contributing to a more harmonious smile. Furthermore, the layering technique employed, particularly when additional porcelain or ceramic layers are applied, is essential for both cosmetic enhancement and structural integrity. Lastly, considerations of occlusion are paramount, ensuring proper alignment and contact between teeth to prevent premature wear and discomfort. By exploring these facets in zirconia restorations across different abutment types, this inquiry seeks to illuminate best practices for achieving favorable treatment outcomes in dental restoration procedures. The choice of zirconia composition, framework design, and shade must be carefully tailored to suit the characteristics of each individual abutment. This emphasizes the significance of adopting a tailored approach to tackle the distinct challenges posed by every clinical scenario. The manuscript provides detailed observations from a clinical case involving the restoration of anterior teeth utilizing monolithic zirconia-fixed dental prostheses. Through a combination of root canal treatment and composite buildup, successful restoration was achieved, with meticulous attention paid to aesthetic considerations. The utilization of computer-aided designing/computer-aided manufacturing (CAD/CAM) technology in crafting zirconia restorations ensured precise fit and superior biocompatibility, contributing to the overall success of the treatment. The study underscores the importance of personalized treatment strategies in achieving optimal outcomes in anterior teeth restoration, emphasizing the need for careful consideration of various factors such as design, composition, and shade selection. Overall, the findings shed light on the potential of zirconia-based restorations in addressing the unique challenges associated with anterior teeth rehabilitation, offering valuable insights for dental practitioners striving to deliver aesthetically pleasing and functionally sound outcomes for their patients.
PubMed: 38725786
DOI: 10.7759/cureus.57889 -
Dental Materials : Official Publication... Feb 2024Investigate attrition simulation using CAD/CAM leucite-reinforced glass-ceramic antagonists on occlusal vs. buccal enamel.
OBJECTIVE
Investigate attrition simulation using CAD/CAM leucite-reinforced glass-ceramic antagonists on occlusal vs. buccal enamel.
METHODS
Three dental materials with known wear rates (resin-modified glass-ionomer, micro-filled, and fine particle composites) validated the wear simulator (CAD/CAM glass-ceramic antagonists, 200 cycles, 80 N load, deionised water irrigation, 0.7 mm sliding movement). Following this, human molars were sectioned into paired occlusal and buccal polished samples (n = 8/gp). Exposed 1.5 mm Ø enamel areas were subjected to attritional wear with and without pre-immersion in citric acid (5 min, 0.3%, pH 3.8). Profilometry measured step-height enamel wear and surface microhardness at different depths was calculated using Vickers indentation at 0.1 N and 0.5 N loads.
RESULTS
Dental material wear using the CAD/CAM antagonists showed consistency with previous data: mean (SD) resin-modified glass ionomer material loss of 177.77 (16.89) µm vs. 22.15 (1.30) µm fine particle hybrid composite resin wear vs. 13.63 (1.02) µm micro filled composite resin wear (P < 0.001). The coefficient of variation was less than 10%. Following validation, enamel sample wear was significantly increased when attrition was introduced (P < 0.001) independent of buccal vs. occlusal sample location (P < 0.05). Attrition resulted in occlusal wear of 26.1 ± 4.5 µm vs. buccal 26.3 ± 1.2 µm and attrition/erosion resulted in occlusal wear of 26.05 ± 4.46 µm vs. buccal 25.27 ± 1.16 µm. Whereas erosion-alone resulted in occlusal wear of 1.65 ± 0.13 µm and buccal 1.75 ± 0.03 µm. Microhardness testing at different loads revealed significantly greater hardness reductions in occlusal enamel vs. buccal enamel for 0.1 KgF indentations (P < 0.001) whereas in contrast 0.5 KgF indentations showed no differences.
SIGNIFICANCE
Wear simulation with CAD/CAM glass ceramic antagonists produced consistent wear in dental materials and human enamel, regardless of enamel surface origin. Lighter (0.1 KgF) hardness testing of occlusal vs. buccal origin revealed damage to the mechanical integrity of the superficial worn enamel.
Topics: Humans; Dental Porcelain; Tooth Attrition; Ceramics; Dental Materials; Composite Resins; Dental Enamel; Materials Testing; Surface Properties; Computer-Aided Design; Acrylic Resins; Aluminum Silicates; Silicon Dioxide
PubMed: 37951749
DOI: 10.1016/j.dental.2023.11.004 -
Clinical Oral Investigations Jul 2023The purpose of this study was to perform an integrative review on laser texturing the inner surface of lithium disilicate-reinforced glass ceramic or zirconia to... (Review)
Review
Surface modification of zirconia or lithium disilicate-reinforced glass ceramic by laser texturing to increase the adhesion of prosthetic surfaces to resin cements: an integrative review.
OBJECTIVE
The purpose of this study was to perform an integrative review on laser texturing the inner surface of lithium disilicate-reinforced glass ceramic or zirconia to increase their bond strength to resin-matrix cements.
MATERIALS AND METHOD
A bibliographic review was performed on PubMed using the following search terms: "zirconia" OR "lithium disilicate" AND "laser" AND "surface" OR "roughness" AND "bond strength" AND "luting agent" OR "resin cement." Studies published in English language until March 15, 2023, were selected regarding the purpose of this study.
RESULTS
A total of fifty-six studies were identified althoug thirteen studies were selected. The findings revealed that zirconia surfaces were significantly modified after laser irradiation resulting in macro-scale aligned retentive regions with depth values ranging from 50 to 120 µm. Average roughness values of laser-textured zirconia by Er,Cr:YSGG laser (~ 0.83 µm) were quite similar when compared to grit-blasted zirconia surfaces (~ 0.9 µm) although roughness increased up to 2.4 µm depending on the laser type and parameters. Lithium disilicate-reinforced glass ceramics textured with Er:YAG revealed an average roughness of around 3.5 µm while surfaces textured using Nd:YAG laser revealed an average roughness of 2.69 µm; that was quite similar to the roughness values recorded for etched surfaces (2.64 µm). The shear bond strength (SBS) values of zirconia surfaces textured on Nd:YVO laser irradiation were slightly higher (~ 33.5 MPa) than those recorded for grit-blasted zirconia surfaces (28 MPa). Laser-textured zirconia surfaces on CO laser revealed higher SBS values (18.1 ±0.8 MPa) than those (9.1 ± 0.56 MPa) recorded for untreated zirconia surfaces. On lithium disilicate-reinforced glass ceramics, higher SBS values to resin-matrix cements were recorded for specimens textured with a combination of fractional CO laser irradiation and HF acid etching (~ 22-24 MPa) when compared with grit-blasted specimens (12.2 MPa). Another study revealed SBS values at around 27.5 MPa for Er:YAG-textured lithium disilicate-reinforced glass ceramics to resin-matrix cements.
CONCLUSIONS
The laser irradiation at high power increases the roughness of the inner surface of lithium disilicate-reinforced glass ceramic or zirconia leading to an enhanced bond strength to resin-matrix cements. Thus, the laser type and irradiation parameters can be adjusted to enhance the macro- and micro-scale retention of zirconia and glass ceramic surfaces to resin-matrix cements.
CLINICAL RELEVANCE
Alternative methods for surface modification of lithium disilicate-reinforced glass ceramic and zirconia surfaces have been assessed to provide proper morphological aspects for enhanced adhesion to resin-matrix cements. An increase in the bond strength of glass ceramics or zirconia to resin-matrix cements can improve the long-term performance of cemented prosthetic structures in the oral cavity.
Topics: Resin Cements; Lithium; Carbon Dioxide; Dental Bonding; Surface Properties; Ceramics; Dental Porcelain; Shear Strength; Lasers, Solid-State; Materials Testing; Zirconium
PubMed: 37069409
DOI: 10.1007/s00784-023-05016-z -
Journal of Personalized Medicine Feb 2024No systematic review or meta-analysis has been identified that provides a clinician's perspective on the shade selection process for ceramic restorations. The aim of the... (Review)
Review
BACKGROUND
No systematic review or meta-analysis has been identified that provides a clinician's perspective on the shade selection process for ceramic restorations. The aim of the present systematic review is to find and systematize the available knowledge by referring to the methods to assess the color of dental ceramics.
METHODS
The final search was performed on 10 December 2023 in six search engines. The keywords used in the search strategy were as follows: ("color matching" OR "shade matching" OR "color measurement" AND "porcelain" OR "dental ceramics") AND "dentistry" AND "accuracy".
RESULTS
The search strategy identified 139 potential articles. After the screening process, sixteen articles were included in the review.
CONCLUSIONS
In conclusion, the most common method, the visual method, has lower accuracy and repeatability. Devices like spectrophotometers and colorimeters provide precise, repeatable, and objective measurements, but fail to be widely applied in everyday clinical practice. Clinicians should not rely solely on their senses for shade determination, but should turn to quantitative methods. Colorimetric devices connected to mobile applications are an interesting and useful tool. Software and apps based on artificial intelligence are emerging as promising tools, but they require further research.
PubMed: 38540994
DOI: 10.3390/jpm14030252 -
Journal of the Mechanical Behavior of... Oct 2023The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of...
PURPOSE
The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of polymerization-induced cracks, and tooth deformation of structurally compromised molars restored with lithium disilicate inlays and overlays in combination with Immediate Dentin Sealing (IDS).
MATERIAL AND METHODS
Human molars (N = 64) were randomly assigned to four different preparation designs: Undermined Inlay (UI), Extended Inlay (EI), Restricted Overlay (RO), and Extended Overlay (EO). The teeth were restored using lithium disilicate partial restorations and subjected to thermomechanical fatigue in a chewing simulator (1,2 × 10 (Mondelli et al., 2007) cycles on 50 N, 8000x 5-55 °C), followed by load to failure testing. In silico finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. Fracture strengths were statistically analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using Fisher exact test.
RESULTS
The propagation of polymerization-induced cracks did not significantly differ among preparation designs. All specimens withstood chewing simulator fatigue, with no visible cracks in teeth or restorations. Fracture strength was significantly influenced by preparation design, with restricted overlay (RO) showing higher fracture strength compared to extended inlay (EI) (p = .042). Tooth deformation and fracture resistance correlated between in vitro and in silico analyses). UI exhibited a statistically less destructive failure pattern than EO (p < .01) and RO (p = .036). No statistically significant influence of the preparation design on repairability was observed. Groups with higher repairability rates experienced increased tooth deformation, leading to less catastrophic failures.
CONCLUSIONS
The preparation design affected the fracture strength of compromised molars restored with lithium disilicate inlays and overlays, with significantly lower fracture strength for an extended inlay. The failure pattern of lithium disilicate overlays is significantly more destructive than that of undermined and extended inlays. The finite element analysis showed more tooth deformation in the inlay restorations, with lower forces in the roots, leading to less destructive fractures. Since cusp coverage restorations fracture in a more destructive manner, this study suggests the undermined inlay preparation design as a viable option for restoring weakened cusps.
Topics: Humans; Flexural Strength; Molar; Dental Porcelain; Fatigue; Fractures, Bone
PubMed: 37659167
DOI: 10.1016/j.jmbbm.2023.106096 -
Clinical and Experimental Dental... Feb 2024The objective of this in vitro study was to evaluate the shear bond strength between the ceramic veneer and additively manufactured titanium with different surface...
OBJECTIVES
The objective of this in vitro study was to evaluate the shear bond strength between the ceramic veneer and additively manufactured titanium with different surface treatments, and to compare with milled titanium. Also, to characterize the surface and the presence of an α-case layer of additively manufactured and milled titanium.
MATERIAL AND METHODS
Sixty additively manufactured titanium grade 23, and 20 milled titanium grade 4 cylindrical specimens were divided into four groups based on surface treatments, air-particle abrasion and grinding. After ceramic veneering half of each group were thermocycled. The bond strength was analyzed using a shear bond strength test. The surfaces were analyzed using interferometry and scanning electron microscopy.
RESULTS
The grinding procedure and air-particle abrading pressure had no significant effect on the shear bond strength (p = .264 and p = .344). Thermocycling showed a tendency towards an effect but not significant (p = .052). The group with the highest air-abrading pressure showed the highest surface roughness. No presence of an α-case layer was detected in any of the groups.
CONCLUSION
Additively manufactured titanium grade 23 may be veneered with ceramics without prior grinding of the surfaces.
Topics: Dental Porcelain; Titanium; Dental Bonding; Surface Properties; Materials Testing; Ceramics
PubMed: 38044540
DOI: 10.1002/cre2.820 -
Medicina (Kaunas, Lithuania) Sep 2023: Implant-supported single crowns have become a routine approach for the replacement of missing single teeth, being considered as one of the most common ways of...
: Implant-supported single crowns have become a routine approach for the replacement of missing single teeth, being considered as one of the most common ways of rehabilitation when adjacent teeth are healthy. The present retrospective study aimed to investigate the risk factors possibly associated with failure and technical complications of implant-supported single crowns and their supporting implants. : Patients treated at one faculty (2009-2019) were considered for inclusion. Complications investigated included ceramic fracture/chipping, crown loss of retention/mobility, crown failure/fracture, loosening/loss/fracture of prosthetic screw, and implant failure/fracture. Any condition/situation that led to the removal/replacement of crowns (implant failure not included) was considered prosthesis failure. Univariate/multivariate Cox regression models were used to evaluate the associations between clinical covariates and failure. : 278 patients (358 crowns) were included. Mean ± SD follow-up was 56.5 ± 29.7 months. Seven implants (after a mean of 76.5 ± 43.7 months) and twenty crowns (21.3 ± 23.5 months) failed. The cumulative survival rate (CSR) for crowns was 93.5% after 5, remaining at 92.2% between 6 and 11 years. The most common reasons for crown failure were porcelain large fracture ( = 6), crown repeatedly loose ( = 6), and porcelain chipping ( = 5). Men and probable bruxism were identified in the Cox regression model as being associated with crown failure. The most common observed technical complications were mobility of the crown and chipping of the ceramic material, with the latter being observed even in crowns manufactured of monolithic zirconia. Cases with at least one technical complication (not considering loss of screw hole sealing) were more common among probable bruxers than in non-bruxers ( = 0.002). Cases of ceramic chipping were more common among bruxers than in non-bruxers ( = 0.014, log-rank test). : Probable bruxism and patient's sex (men) were factors associated with a higher risk of failure of implant-supported single crowns.
Topics: Male; Humans; Retrospective Studies; Bruxism; Dental Porcelain; Risk Factors; Bone Screws; Fractures, Bone
PubMed: 37763722
DOI: 10.3390/medicina59091603 -
Journal of Prosthodontics : Official... Dec 2023The available independent data on the translucency of novel pre and fully sintered chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium...
PURPOSE
The available independent data on the translucency of novel pre and fully sintered chairside computer-aided design and computer-aided manufacturing (CAD-CAM) lithium disilicate are limited. This comparative in vitro study evaluated the translucency degree of pre and fully sintered chairside CAD-CAM lithium disilicate crowns after optional, required, and additional firing processes.
MATERIALS AND METHODS
One hundred and five maxillary left central incisor crowns manufactured by three different CAD-CAM lithium disilicate brands shade A1 were assigned into seven groups as follows (n = 15): (1) Straumann n!ce without sintering; (2) Straumann n!ce with one additional sintering process; (3) Straumann n!ce with two additional sintering processes; (4) Amber Mill with one sintering process; (5) Amber Mill with two sintering processes; (6) IPS e.max CAD with one sintering process; and (7) IPS e.max CAD with two sintering processes. The translucency of all crowns was evaluated with a color imaging spectrophotometer. All statistical analyses were performed using statistical software. A standard level of significance was set at α < 0.05.
RESULTS
All the milled crowns presented different degrees of translucency, and additional sintering processes altered it. IPS e.max CAD with two (4.33 ± 0.26) and one (4.01 ± 0.15) sintering processes displayed the highest translucency, whereas Straumann n!ce with no sintering process provided the lowest value (2.82 ± 0.16).
CONCLUSIONS
The translucency of chairside lithium disilicate single-unit full-coverage restorations manufactured with subtractive technology was significantly influenced by the brand and the number of sintering processes. The traditional presintered IPS e.max CAD and the fully crystallized glass-ceramic Straumann n!ce considerably increased the translucency after one additional firing process, whereas Amber Mill decreased its translucency.
Topics: Amber; Dental Porcelain; Ceramics; Crowns; Computer-Aided Design; Materials Testing
PubMed: 36609993
DOI: 10.1111/jopr.13644 -
Medical Science Monitor : International... Feb 2024BACKGROUND Preshaded monolithic zirconia (MLZ) is reported to have high translucency. This study aimed to assess the effect of chlorhexidine gluconate (ChG) mouthwash on...
Influence of Chairside Simulated Adjustment (Finishing and Polishing) Protocol and Chlorhexidine Mouthwash Immersion on Color Stability and Translucency of 2 and 3 Preshaded Multilayered Monolithic Zirconia.
BACKGROUND Preshaded monolithic zirconia (MLZ) is reported to have high translucency. This study aimed to assess the effect of chlorhexidine gluconate (ChG) mouthwash on color and translucency parameter (TP) of 2 different preshaded MLZ dental ceramics after clinical adjustment. MATERIAL AND METHODS Two MLZ disk-shaped specimens [NPM (Nacera Pearl Multi-Shade) (n=72) and CZM (Ceramill Zolid FX Multilayer)] (n=72) were simulated for clinical adjustment, finished, and polished using 2 adjustment kits [recommended kit, third-party kit: Diasynt Plus and SUN (n=12 each)] and later immersed in ChG mouthwash (Avohex) for 2 weeks. Difference in color (ΔE) and TP (Y) were calculated using the CIELab formula after measuring the coordinates (Lab) with a colorimeter. Individual changes in color and TP were assessed on the Clinical acceptance (perceptible) threshold (CAT/CPT) and Translucency perception threshold (TPT), respectively. Differences between the 2 ceramics were assessed using one-way ANOVA and post hoc tests, with all differences considered significant at P<0.05. RESULTS NPM and CZM differed in color at baseline despite having the same Vita shade combination. Between the 2 preshaded MLZ ceramics, NPM showed significant changes in color when adjusted with a third-party kit. Chlorhexidine produced changes in color and TP that were designated as clinically perceptible (ΔE=1.0 to 3.3) on the CAT/CPT and TPT scales, irrespective of the adjustment kit used. ChG produced the least or no changes in glazed MLZ specimens. CONCLUSIONS ChG mouthwash, whenever prescribed for preshaded MLZ restoration, should be adjusted prior to final glazing to avoid clinical adjustments that adversely affects color and translucency of the restoration.
Topics: Color; Chlorhexidine; Mouthwashes; Immersion; Materials Testing; Surface Properties; Ceramics; Dental Porcelain; Zirconium
PubMed: 38374614
DOI: 10.12659/MSM.943404 -
Journal of Pharmacy & Bioallied Sciences Feb 2024Surface roughness and hardness are key factors that influence the clinical performance and durability of denture teeth. Understanding variations in these properties...
BACKGROUND
Surface roughness and hardness are key factors that influence the clinical performance and durability of denture teeth. Understanding variations in these properties among different denture teeth materials can assist in selecting the most suitable materials for optimal patient outcomes. This study aimed to investigate the surface roughness and hardness of four commonly used denture teeth materials: acrylic resin, composite resin, porcelain, and nanohybrid composite.
MATERIALS AND METHODS
Ten specimens were prepared for each denture teeth material, resulting in a total of 40 specimens. Surface roughness was assessed using a profilometer, and measurements were recorded in micrometers (μm). Hardness was determined using a Vickers hardness tester, and results were expressed as Vickers hardness numbers (VHN). The surface roughness and hardness data were analyzed using appropriate statistical tests (e.g., analysis of variance), with significance set at < 0.05.
RESULTS
The results revealed significant differences in both surface roughness and hardness among the different denture teeth materials ( < 0.05). Acrylic resin exhibited the highest surface roughness (mean ± standard deviation: 3.45 ± 0.78 μm) and the lowest hardness (mean ± standard deviation: 45.6 ± 2.3 VHN). Composite resin demonstrated intermediate values of surface roughness (mean ± standard deviation: 1.87 ± 0.54 μm) and hardness (mean ± standard deviation: 65.2 ± 3.9 VHN). Porcelain demonstrated the smoothest surface (mean ± standard deviation: 0.94 ± 0.28 μm) and the highest hardness (mean ± standard deviation: 78.5 ± 4.1 VHN). Nanohybrid composite displayed surface roughness and hardness values similar to composite resin.
CONCLUSION
This study demonstrated significant variations in surface roughness and hardness among the different denture teeth materials evaluated. Acrylic resin exhibited the roughest surface and lowest hardness, while porcelain demonstrated the smoothest surface and highest hardness. Composite resin and nanohybrid composite exhibited intermediate values. These findings provide valuable insights for prosthodontic practitioners in selecting denture teeth materials based on specific clinical requirements, aiming to achieve optimal aesthetics, reduced plaque accumulation, and improved wear resistance.
PubMed: 38595483
DOI: 10.4103/jpbs.jpbs_644_23