scholarly journals Effect of Yttria Content on the Translucency and Masking Ability of Yttria-Stabilized Tetragonal Zirconia Polycrystal

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4726
Author(s):  
Young-Eun Cho ◽  
Young-Jun Lim ◽  
Jung-Suk Han ◽  
In-Sung Luke Yeo ◽  
Hyung-In Yoon
Keyword(s):  
Tetragonal Zirconia ◽  
In Vitro Study ◽  
Lithium Disilicate ◽  
Color Difference ◽  
Minimum Thickness ◽  
B Values ◽  
Yttria Content ◽  
Negative Effect ◽  
Tetragonal Zirconia Polycrystal

Translucent zirconia, manufactured by increasing the yttria content, offers improved translucency, but may have a negative effect on esthetic outcomes under clinical conditions such as discolored abutment because of the reflection of the underlying color. The purpose of this in vitro study was to compare the translucency parameter and masking ability of 3 mol % yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP (Katana HT)), 4Y-ZP (Katana STML), and 5Y-ZP (Katana UTML) with those of lithium disilicate (Rosetta SM). Zirconia and lithium disilicate specimens of 10 mm diameters and 0.8 and 1.5 mm thicknesses were fabricated. Their CIE L*a*b* values (L*, brightness; a*, red-green value; b*, yellow-blue value) were measured at the center of the specimens against black and white backgrounds using a spectrophotometer, and translucency parameter (TP) values were determined. The microstructure of the specimens was observed using scanning electron microscopy. Four cylindrical backgrounds of different shades were prepared. The zirconia and lithium disilicate specimens were placed on the backgrounds without any intervening medium. CIE L*a*b* values were obtained, and the color difference value (ΔE) was calculated. Thresholds for acceptability and perceptibility were assumed as ΔE = 5.5 and ΔE = 2.6, respectively, to evaluate masking ability. Data were compared using one-way analysis of variance and post-hoc was performed using Scheffe’s test (α = 0.05). In zirconia specimens, the TP value increased as the yttria content increased from 3 mol %, through 4 mol % to 5 mol %, and all zirconia specimens showed lower TP values than lithium disilicate specimens did. All zirconia specimens showed optimal masking ability against a normal dentin shade (ND3) and acceptable masking ability against titanium at a minimum thickness of 1.5 mm. However, no zirconia specimen could mask severely discolored dentin (ND9), regardless of thickness. The decrease in zirconia thickness from 1.5 to 0.8 mm significantly increased translucency. Monolithic Y-TZP ceramics could mask a normal dentin background but could not mask severely discolored dentin at either 0.8 or 1.5 mm thicknesses.

scholarly journals Effect of Hydrothermal Aging and Beverages on Color Stability of Lithium Disilicate and Zirconia Based Ceramics

Medicina ◽  
2019 ◽  
Vol 55 (11) ◽  
pp. 749 ◽  
Author(s):  
Satheesh B. Haralur ◽  
Noura Raqe S. Alqahtani ◽  
Fatimah Alhassan Mujayri
Keyword(s):  
Green Tea ◽  
In Vitro Study ◽  
Color Stability ◽  
Lithium Disilicate ◽  
Color Difference ◽  
Hydrothermal Aging ◽  
Monolithic Zirconia ◽  
Post Hoc ◽  
Coloring Agents

Background and aim: All-ceramic prosthesis is widely used in modern dental practice because of its improved physico-mechanical and optical properties. These restorations are exposed to coloring agents from various nutrition and beverages in the oral cavity. Long-term color stability is critical for the success of these restorative materials. The purpose of this in vitro study was to assess the effect of common beverages and mouthwash on the color stability of lithium disilicate (LD), monolithic zirconia (MZ) and bilayer zirconia (BZ) surfaces. Material and methods: Thirty disc-shaped specimens from each material were fabricated; each group was subdivided (n = 10) according to coffee, green tea and chlorhexidine immersion solutions. The baseline color of ceramic discs was recorded according to the CIE L*a*b* system with a portable spectrophotometer. The second measurement was recorded after 3000 thermocycling and immersion in coloring agents for 7 days. The mean color difference was calculated and data were compared with Kruskal-Wallis and Mann-Whitney post hoc tests (0.05). Results: ΔE values for LD with the immersion of coffee, tea, and Chlorhexidine gluconate (CHG) were 1.78, 2.241 and 1.58, respectively. Corresponding ΔE values for MZ were 5.60, 5.19, and 4.86; marginally higher than the clinically acceptable level of 3.5. Meanwhile, BZ showed better color stability compared to MZ with ΔE values of 4.22, 2.11 and 1.43. Conclusion: Among the ceramics evaluated, LD ceramic was found to be more color stable, while MZ ceramics displayed a higher susceptibility to discoloration. MZ and BZ ceramic colors were significantly altered with coffee immersion, while LD ceramics were more affected by green tea.

scholarly journals Tooth discoloration induced by apical plugs with hydraulic calcium silicate-based cements in teeth with open apices—a 2-year in vitro study

2021 ◽  
Author(s):  
Ralf Krug ◽  
C. Ortmann ◽  
S. Reich ◽  
B. Hahn ◽  
G. Krastl ◽  
...  
Keyword(s):  
Calcium Silicate ◽  
In Vitro Study ◽  
Color Difference ◽  
Blood Contamination ◽  
Tooth Color ◽  
Color Changes ◽  
Gutta Percha ◽  
Tooth Discoloration ◽  
Post Hoc

Abstract Objectives To assess tooth discoloration induced by different hydraulic calcium silicate-based cements (HCSCs), including effects of blood and placement method. Materials and methods Eighty bovine teeth cut to a length of 18 mm (crown 8 mm, root 10 mm) were randomly assigned to 10 groups (n = 8), receiving orthograde apical plug treatment (APT). Apical plugs were 4 mm in length and made of ProRoot MTA (Dentsply), Medcem MTA (Medcem), TotalFill BC RRM Fast Set Putty (Brasseler), or Medcem Medical Portland Cement (Medcem) plus bismuth oxide (Bi2O3) with and without bovine blood. Further, orthograde (with or without preoperative adhesive coronal dentin sealing) and retrograde APT were compared. Teeth were obturated with gutta-percha and sealer, sealed with composite and stored in distilled water. Tooth color was measured on apical plug, gutta-percha/sealer, and crown surface before treatment versus 24 h, 1, 3, 6, 12, and 24 months after treatment by spectrophotometry. Color difference (ΔE) values were calculated and analyzed by Shapiro–Wilk test, ANOVA with post hoc tests, Friedman test, t test, and post hoc tests with Bonferroni correction (α = .05). Results Tooth discoloration occurred in all groups with no significant differences between HCSCs (p > .05). After 24 months, color changes were prominent on roots but insignificant on crowns. Blood contamination induced a significantly decreased luminescence (p < .05). Blood had a stronger impact on tooth color than Bi2O3. No relevant effects of retrograde placement (p > .05) or preoperative dentin sealing (p > .05) were detected. Conclusions Apical plugs of the tested HCSCs cause discoloration of bovine roots, but not discoloration of bovine tooth crowns within a 24-month period. Clinical relevance APT should be performed carefully while avoiding direct contact with the coronal dentin, and in that case no aesthetic impairments occur.

scholarly journals Accuracy of Guided Implant Surgery in the Edentulous Jaw Using Desktop 3D-Printed Mucosal Supported Guides

2021 ◽  
Vol 10 (3) ◽  
pp. 391
Author(s):  
Rani D’haese ◽  
Tom Vrombaut ◽  
Geert Hommez ◽  
Hugo De Bruyn ◽  
Stefan Vandeweghe
Keyword(s):  
In Vitro Study ◽  
Angular Deviation ◽  
Implant Surgery ◽  
Implant Position ◽  
Surgical Guides ◽  
Negative Effect ◽  
Bone Level ◽  
3D Printed ◽  
Implant Alignment

Purpose: The aim of this in vitro study is to evaluate the accuracy of implant position using mucosal supported surgical guides, produced by a desktop 3D printer. Methods: Ninety implants (Bone Level Roxolid, 4.1 mm × 10 mm, Straumann, Villerat, Switzerland) were placed in fifteen mandibular casts (Bonemodels, Castellón de la Plana, Spain). A mucosa-supported guide was designed and printed for each of the fifteen casts. After placement of the implants, the location was assessed by scanning the cast and scan bodies with an intra-oral scanner (Primescan®, Dentsply Sirona, York, PA, USA). Two comparisons were performed: one with the mucosa as a reference, and one where only the implants were aligned. Angular, coronal and apical deviations were measured. Results: The mean implant angular deviation for tissue and implant alignment were 3.25° (SD 1.69°) and 2.39° (SD 1.42°) respectively, the coronal deviation 0.82 mm (SD 0.43 mm) and 0.45 mm (SD 0.31 mm) and the apical deviation 0.99 mm (SD 0.45 mm) and 0.71 mm (SD 0.43 mm). All three variables were significantly different between the tissue and implant alignment (p < 0.001). Conclusion: Based on the results of this study, we conclude that guided implant surgery using desktop 3D printed mucosa-supported guides has a clinically acceptable level of accuracy. The resilience of the mucosa has a negative effect on the guide stability and increases the deviation in implant position.

scholarly journals The Accuracy and Reliability of Tooth Shade Selection Using Different Instrumental Techniques: An In Vitro Study

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7490
Author(s):  
Nattapong Sirintawat ◽  
Tanyaporn Leelaratrungruang ◽  
Pongsakorn Poovarodom ◽  
Sirichai Kiattavorncharoen ◽  
Parinya Amornsettachai
Keyword(s):  
Intraclass Correlation ◽  
In Vitro Study ◽  
Control Group ◽  
Intraoral Scanner ◽  
Control Groups ◽  
B Values ◽  
Cie Lab ◽  
And Control ◽  
Shade Selection

This study aimed to investigate and compare the reliability and accuracy of tooth shade selection in the model using 30 milled crowns via five methods: (1) digital single-lens reflex (DSLR) camera with twin flash (TF) and polarized filter (DSLR + TF), (2) DSLR camera with a ring flash (RF) and polarized filter (DSLR + RF), (3) smartphone camera with light corrector and polarized filter (SMART), (4) intraoral scanner (IOS), and (5) spectrophotometer (SPEC). These methods were compared with the control group or manufacturer’s shade. The CIE Lab values (L, a, and b values) were obtained from five of the methods to indicate the color of the tooth. Adobe Photoshop was used to generate CIE Lab values from the digital photographs. The reliability was calculated from the intraclass correlation based on two repetitions. The accuracy was calculated from; (a) ΔE calculated by the formula comparing each method to the control group, (b) study and control groups were analyzed by using the Kruskal–Wallis test, and (c) the relationship between study and control groups were calculated using Spearman’s correlation. The reliability of the intraclass correlation of L, a, and b values obtained from the five methods showed satisfactory correlations ranging from 0.732–0.996, 0.887–0.994, and 0.884–0.999, respectively. The ΔE from all groups had statistically significant differences when compared to the border of clinical acceptance (ΔE = 6.8). The ΔE from DSLR + TF, DSLR + RF, SMART, and SPEC were higher than clinical acceptance (ΔE > 6.8), whereas the ΔE from IOS was 5.96 and all of the L, a, and b values were not statistically significantly different from the manufacturer’s shade (p < 0.01). The ΔE of the DSLR + RF group showed the least accuracy (ΔE = 19.98), whereas the ∆E of DSLR + TF, SMART, and SPEC showed similar accuracy ∆E (ΔE = 10.90, 10.57, and 11.57, respectively). The DSLR camera combined with a ring flash system and polarized filter provided the least accuracy. The intraoral scanner provided the highest accuracy. However, tooth shade selection deserves the combination of various techniques and a professional learning curve to establish the most accurate outcome.

scholarly journals The Influence of Different Surface Cleansing Agents on Shear Bond Strength of Contaminated Lithium Disilicate Ceramic: An In Vitro Study

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Taksid Charasseangpaisarn ◽  
Pattarawadee Krassanairawiwong ◽  
Chanidapa Sangkanchanavanich ◽  
Atima Kurjirattikan ◽  
Kanyarak Kunyawatyuwapong ◽  
...  
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Sodium Hydroxide Solution ◽  
Resin Composite ◽  
In Vitro Study ◽  
Lithium Disilicate ◽  
Surface Element ◽  
Similar Amount ◽  
Modes Of Failure

Background and Purpose. Contamination of the lithium disilicate (LDS) during the try-in procedure is unavoidable and may weaken the bond strength of restoration. The purpose of this study was to investigate the efficacy of different surface cleansing agents on the shear bond strength (SBS) of contaminated LDS. Materials and Methods. Seventy LDS specimens were randomly divided into seven groups. The first group was noncontaminated surface (PC). The six other groups were contaminated with the saliva and silicone disclosing medium and treated with no surface cleansing agent (NC); phosphoric acid (PO); Ivoclean (IV); sodium hydroxide solution (NA); Restorative Cleansing Agent (RC); and hydrofluoric acid (HF). Then, LDS specimens were cementated with Panavia V5 to resin composite rod. Each specimen was subjected to an SBS test. The modes of failure was inspected under light microscope. The surface element of each group was examined by SEM-EDS. Results. The results were analyzed with one-way ANOVA and Tamhane’s T2. The mean SBS value of NC was significantly lower than others ( p < 0.05 ), and HF was significantly higher than others ( p < 0.05 ). However, PC, PO, IV, NA, and RC were not significantly different from each other ( p > 0.05 ). The mode of failure was mostly adhesive failure in every group. The surface showed similar amount of elements in every group. Conclusions. The SBS of LDS was reduced by saliva and silicone disclosing medium contamination which can be restored using acid- and alkaline-based surface cleansing agents before the cementation procedure.

scholarly journals Stain Susceptibility of 3D-Printed Nanohybrid Composite Restorative Material and the Efficacy of Different Stain Removal Techniques: An In Vitro Study

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5621
Author(s):  
Nawal Alharbi ◽  
Amal Alharbi ◽  
Reham Osman
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Color Difference ◽  
Restorative Material ◽  
Significant Interaction Effect ◽  
Black And White ◽  
Stain Removal ◽  
3D Printed ◽  
Nanohybrid Composite

Recent burgeoning development in material science has introduced a 3D-printable, nanohybrid composite resin restorative material. However, its performance has not yet been investigated. This study evaluates the stain susceptibility and efficacy of different stain removal techniques. A total of 120 labial veneers were fabricated using milling (n = 60) and SLA 3D-printing (n = 60). Based on the immersion media: coffee, tea and artificial saliva, each group was divided into three sub-groups (n = 20). Stain susceptibility was evaluated by calculating color difference (∆E00) at 12 and 24 days using a spectrophotometer against black and white backgrounds. Collected data were analyzed with ANOVA and Tukey’s post hoc test (p < 0.05). A significant interaction effect was found between the staining mediums and fabrication methods in both black and white backgrounds (p < 0.001). 3D-printed restorations showed significantly higher stain susceptibility than milled restorations (p < 0.001). Prolonged immersion time increased the color difference in both groups. In-office bleaching was more effective in stain removal in both 3D-printed and milled restoration groups. The susceptibility of the presented novel 3D-printed restorative material to color changes in different immersion mediums was clinically not-acceptable. The clinicians might expect the need to replace the restoration after 1–2 years and thus, recommendation for the use of such a material as a permanent restoration cannot be made but rather as a long-term temporary restoration.

scholarly journals Effect of lithium disilicate ceramic thickness, shade and translucency on transmitted irradiance and knoop microhardness of a light cured luting resin cement

2021 ◽  
Vol 32 (8) ◽  
Author(s):  
Lincoln Pires Silva Borges ◽  
Gilberto Antônio Borges ◽  
Américo Bortolazzo Correr ◽  
Jeffrey A. Platt ◽  
Sidney Kina ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Lithium Disilicate ◽  
Resin Cement ◽  
Control Group ◽  
Ceramic Disc ◽  
All Ceramic ◽  
Light Curing ◽  
Knoop Microhardness ◽  
Ceramic Thickness

AbstractThis in vitro study evaluates the influence of pressed lithium disilicate thickness, shade and translucency on the transmitted irradiance and the Knoop microhardness (KHN) of a light-cured resin cement at two depths. One hundred and thirty-five ceramic discs of IPS e.max Press (Ivoclar Vivadent) were fabricated and divided into twenty-seven groups (n = 5) according to the association between translucency: HT (hight translucency), LT (low translucency), and MO (medium opacity); shade: BL2, A1 and A3.5; and thickness: 0.5 mm, 1.5 mm, and 2.0 mm. One side of each ceramic disc was finished, polished and glazed. The irradiance (mW/cm²) of a multiwave LED light curing unit (Valo, Ultradent) was evaluated with a potentiometer (Ophir 10ª-V2-SH, Ophir Optronics) without (control group) or with interposition of ceramic samples. The microhardness of Variolink Esthetic LC resin cement (Ivoclar Vivadent) was evaluated after 24 h at two depths (100 μm and 700 μm). Data were submitted to ANOVA followed by Tukey’s test (α = 0.05). Irradiance and KHN were significantly influenced by ceramic thickness (p < 0.0001), shade (p < 0.001), translucency (p < 0.0001) and depth (p < 0.0001). Conclusions: the interposition of increasing ceramic thicknesses significantly reduced the irradiance and microhardness of resin cement. Increased depth in the resin cement showed significantly reduced microhardness for all studied groups. Increased ceramic opacity reduced the KHN of the resin cement at both depths for all ceramic thicknesses and shades.

Fracture strength of yttria-stabilized tetragonal zirconia polycrystals crowns with different design: an in vitro study

2011 ◽  
Vol 23 (7) ◽  
pp. 820-826 ◽  
Author(s):  
Christel Larsson ◽  
Sammah El Madhoun ◽  
Ann Wennerberg ◽  
Per Vult von Steyern
Keyword(s):  
Fracture Strength ◽  
Tetragonal Zirconia ◽  
In Vitro Study ◽  
Vitro Study

Force decay of intermaxillary orthodontic elastics: in vitro study

2019 ◽  
Vol 88 (2) ◽  
pp. 91-95
Author(s):  
Hubert Kardach ◽  
Aneta Olszewska ◽  
Ewa Firlej ◽  
Agnieszka Bogdanowicz ◽  
Ewelina Golusińska-Kardach ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
Low Cost ◽  
In Vitro Study ◽  
Ease Of Use ◽  
Force Decay ◽  
Artificial Environment ◽  
Negative Effect ◽  
Progressive Force ◽  
Different Diameters

Introduction. Orthodontic elastics are widely used in orthodontic treatment. It’s been proved that they have advantages such as low cost, ease of use, but also disadvantages, mainly force decay in time and increased entrapment of biofilm. Amount of the force is of extreme significance. This force can be altered by physical or chemical factors. Material and Methods. Latex elastics in 3 different diameters were selected for this study. Each elastic was stretched and placed on hooks that are at specified distances that equal 3 times the diameter of each elastic. The forces produced by stretching was measured using tension gauge and the measurement were taken at specific time intervals of 0h, 3h, 12h, 24h. The same process was repeated for elastics in dry and artificial environment. Results. Elastics in the dry environment showed progressive force decay cause by stretching over time. Just after 3 hours force decay between 6,07% and 8,75% was observed. The biggest loss of force between 13,61 — 16,13 % was measured after 24 hours. Compared to the dry environment, an even more significant force decay was observed in the artificial saliva. After first 3 hours force loss was between 4,99% — 9,22%. The biggest force decay was observed after 24 hours and it was 5 % higher compared to dry environment. Conclusions. 1) The artificial saliva environment and time of exposure to it, have a negative effect on the properties of elastomeric. 2) To maintain the effective orthodontic strength of elastics, they should be replaced every 12 hours.

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