Hanaa Zaghloul - Academia.edu (original) (raw)

Papers by Hanaa Zaghloul

Deleted Journal, Mar 1, 2024

The study aims to assess the influence of hydrothermal aging on gradient zirconia's microstructur... more The study aims to assess the influence of hydrothermal aging on gradient zirconia's microstructure and color stability. Materials and methods: Ten discs were constructed from gradient zirconia blanks (3Y-TZP-5Y-TZP) using CAD\CAM technology. Hydrothermal aging was done in an autoclave. Color parameters (a*, b*, L*) for each disc was measured using a spectrophotometer. In order to investigate the zirconia specimens' crystalline structure, X-ray diffraction (XRD) was performed. Color stability and microstructural changes were examined before and after the aging process. Results: Following hydrothermal aging, a statistically significant decrease in the mean (L*) value was found. However, following hydrothermal aging, a statistically significant increase in the mean (a*) and (b*) values was reported. Regarding the microstructure, hydrothermal aging did not result in any significant changes. Conclusion: Artificial aging has led to color changes in gradient zirconia that were in the clinical acceptability range but has no impact on the microstructure of gradient zirconia.

Statement of Problem With the rise of an esthetic demand for a more natural mimic appearance zirc... more Statement of Problem With the rise of an esthetic demand for a more natural mimic appearance zirconia bridges and frame works are becoming more and more recommended. Having an esthetic strong restoration as zirconia IRFPD is a better option than the aggressive full coverage restoration or a long, painful and expensive procedure as implant retained restoration. Aim of the study is to examine the impact of cyclic loading and two distinct surface treatments modalities on the marginal fit of different designs of Inlay retained fixed partial denture cemented with an MPD containing resin cement. Materials and methods 30 IRFPD were constructed from zirconia with three designs [box, inlay box and winged inlay box] n=10. The samples were split into two subgroups within each group based on the type of surface treatment they received. [sandblasting, Air borne salinization] n=5. IRFPD's were cemented and examined by stereomicroscope for marginal adaptation before and after cyclic loading. Results surface treatments and cyclic loading had significant effect on marginal adaptation of IRFPD's whereas the different design had no significant effect. Conclusion IRFPD is a good alternative to restore missing posterior teeth with application of surface conditioning to zirconia and the use of MDP containing cement.

To evaluate the effect of nanotechnology on bond strength of hybrid ceramics. Twelve CAD/CAM cera... more To evaluate the effect of nanotechnology on bond strength of hybrid ceramics. Twelve CAD/CAM ceramic slices were divided into 3 groups (n=4) (Lava Ultimate [LU], Vita Enamic [VE], and IPS e.max [EM]). Each was subdivided into 2 subgroups (n=2) (hydrofluoric acid etching [HF] and Sandblasting [SB]). Each was subdivided into 2 subdivisions (n=1) (Scotchbond Universal [SbU] and Futurabond U [FbU]). Silane was applied for 1 minute. Five micro-cylinders of RelyX Ultimate were cemented on each slice. 5000 thermocycles were done. Micro-shear bond strength (μSBS) was performed using the universal testing machine. SEM analysis was used to identify the mode of failure and the effect of surface treatment. Surface roughness (Ra) was measured by contact profilometer. Three-way ANOVA was used to study the effect of ceramic material, surface treatment, and universal adhesive on μSBS. Bonferroni’s post-hoc test was used when ANOVA test was significant (P ≤.05). Two-way ANOVA was used to study the effect of ceramic microstructure and surface treatment on surface roughness. LU showed the highest μSBS and the least Ra values. The nanostructure of LU enhanced its bonding properties and decreased its surface roughness. HF and silane application could be considered a reliable surface treatment for bonding of hybrid ceramics. The presence of silane in SbU, in addition to the separate silane application, was enhanced the μSBS of the sandblasted LU.

IOP Conference Series: Materials Science and Engineering

To assess the effect of nano-modification of two CAD/CAM monolithic Zirconia systems (wet and dry... more To assess the effect of nano-modification of two CAD/CAM monolithic Zirconia systems (wet and dry-milled) on microstructural changes and fracture resistance upon aging. Twenty monolithic Zirconia discs (10mm x1.5mm) were divided into 2 groups (n=10) according to fabrication system;wet-milled (Incoris TZI) and dry-milled (CeramillZolid). Each group was subdivided into two subgroups (n=5), whether subjected to aging or not. Aging proceduresincluded accelerated hydrothermal aging and cyclic loading. Microstructural changes were assessed quantitatively and qualitatively using x-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. Discs were subjected to fracture resistance test usinguniversal testing machine. Meansandstandard deviations were recorded for phase transformation (t-m)of Zirconia and repeated ANOVA was used to correlate phase transformation with fracture resistance results (p≤0.05). For aged subgroups, XRD analysis revealed significantly higher phase tr...

Journal of Fundamental and Clinical Research

Background: PEEK is a polymer with lots of significant potentials making it an important candidat... more Background: PEEK is a polymer with lots of significant potentials making it an important candidate in dental applications; however, strong durable bond of PEEK restorations with resin cement is still questionable. Aim: Evaluating the effect of different surface treatment protocols on the bond strength of PEEK surface with resin cement in comparison to Lithium Disilicate ceramic. Methodology: PEEK (P) and Lithium Disilicate discs (LD) were fabricated using CAD/CAM technique. A total of 40 samples were divided into four groups according to surface treatment protocol (n=10): Group (LD): hydrofluoric acid etching followed by silane application. Group (PP): 110 µm alumina particles sandblasting followed by Piranha solution acid etching. Group (PNsi): 110 µm alumina particles sandblasting followed by nano-silica coating and silane coupling agent respectively. Group (PN): 110 µm alumina particles sandblasting followed by nano-silica coating. All specimens underwent thermocycling. All specimens were cemented using universal resin cement. Micro-shear bond strength (μSBS) test was performed using a universal testing machine and the mode of failure was assessed using digital microscope. Surface roughness was assessed before and after surface treatment using optical profilometer. Results: There was no statistically significant difference between (LD) and (PP); both showed the highest (μSBS). No statistically significant difference between (PNsi) and (PN); both showed the lowest (μSBS). However, statistically significant difference was found between (LD, PP) groups and (PNsi, PN) groups. (P-value = 0.028). Conclusion: PP group showed a comparable μSBS results to LD group, whereas, nano-silica coated group showed the lowest bond strength values.

Journal of Fundamental and Clinical Research

Background: Different digital fabrication techniques affect the marginal adaptation of tooth supp... more Background: Different digital fabrication techniques affect the marginal adaptation of tooth supported provisional and final dental prosthesis. However, there is minimal scientific evidence which technique will be effective for producing tooth supported provisional dental prosthesis with predictable marginal fit. Aim of the study: to evaluate the effect of the two CAM fabrication techniques; milling versus 3D printing on the marginal fit of tooth supported restorations. Materials and methods: two abutment teeth of a modified typodont with a missing left mandibular first molar were prepared to receive a ceramic FDP. A master reference stone model was then, constructed. An optical impression (STL file) of the reference model was taken. A provisional tooth supported FDP was designed on the CAD software using the STL file of the reference model. Eight Restorations were fabricated by different CAM techniques. The restorations were divided into two groups according to the fabrication method; group A (milled restorations) (n=4) and group B (3D printed restorations) (n=4). Finally, the marginal fit of the provisional dental prosthesis was assessed by a stereo optical microscope on the stone reference model. Mann-Whitney U test was used to compare between the two groups. The significance level was set at P ≤ 0.05. Results: the results showed that there was no statistically significant difference between the vertical marginal gap values of the two tested groups. Conclusion: The vertical marginal gap values of provisional restorations fabricated by the two tested methods of manufacturing were comparable and within the acceptable range of 120 µ.

Polymers

Background: Minimal evidence exists on the efficacy of different digital manufacturing techniques... more Background: Minimal evidence exists on the efficacy of different digital manufacturing techniques in the fabrication of precise dental working models and provisional prosthesis. Aim of study: The objective was to evaluate the effect of two digital fabrication techniques (CAD/CAM milling and 3D printing) on the accuracy of PMMA working models and marginal fit of PMMA provisional prosthesis. Materials and methods: Two abutment teeth of modified typodont were prepared. A reference stone model was fabricated, and an optical impression was performed to obtain a CAD reference model. Four CAM milled working models and four printed working models were fabricated. CAD software was used to design the provisional prostheses. Group A tested four milled provisional prosthesis, and group B tested four 3D printed prosthesis. The 3D accuracy of working models was assessed by superimposition of the control reference working model on the CAD test working model. A stereo-optical microscope was used to...

Journal of Oral Implantology, 2013

This study evaluated the effect of fabrication techniques and cyclic loading on the vertical marg... more This study evaluated the effect of fabrication techniques and cyclic loading on the vertical marginal fit of implant-supported fixed partial denture (FPD) frameworks. Thirty implant-supported 3-unit FPD frameworks were fabricated on a model system, divided into 3 equal groups (n = 10). The first group (control) was constructed from base metal alloy; the other 2 test groups were constructed from all-ceramic zirconia using a computer-aided design/computer-aided manufacturing (CAD/CAM) Cerec 3 system and a copy milling (Zirkonzahn) system. A cyclic load of 200 N was applied to each framework for up to 50,000 cycles. Linear measurements were made in micrometers of the vertical gap between the framework and the implant-supported abutment at 16 predetermined points before and after cyclic loading. The frameworks were viewed using scanning electron microscopy to inspect any fractographic features. One-way analysis of variance was performed to compare the marginal discrepancy values of the ...

Brazilian Dental Journal

The aim of this study was to evaluate the survival of laminate veneers constructed using a recent... more The aim of this study was to evaluate the survival of laminate veneers constructed using a recent polymer-infiltrated ceramic network material following the aesthetic pre-evaluative temporary (APT) technique of tooth preparation in comparison to traditional technique. Six patients received 54 laminate veneers. They were divided into two equal groups (n=27) according to the technique of tooth preparation: group T: traditional technique and group A: aesthetic pre-evaluative temporary technique. VITA ENAMIC material was used for CAD/CAM construction of laminate veneers. Cementation was performed using a light cured resin cement. The laminate veneers were evaluated at baseline, after 3, 6 and 12 months according to the modified United States Public Health Service (USPHS) criteriea. The data was collected, tabulated and statistically analyzed. Secondary caries, endodontic complications, cracks and loss of retention were not noted in any laminate veneer. Extensive fractures were not detec...

Egyptian Dental Journal

Objective: To assess the effect of two surface treatment protocols of two pressable lithium disil... more Objective: To assess the effect of two surface treatment protocols of two pressable lithium disilicate ceramics with different thicknesses on the surface roughness and topography. Material and methods: Sixty four lithium disilicate ceramic discs were divided into two groups (n=32); IPS e.max Press and Initial TM LiSi Press. Each group was subdivided into two subgroups (n=16) according to thicknesses (0.5mm and 1mm). Each subgroup was divided into two subdivisions (n=8) according to the surface treatment; Er:Cr:YSGG Laser and hydrofluoric acid etching. Artificial aging was performed for all the specimens. Surface roughness (Ra) before and after surface treatment protocol was measured using contact stylus profilometer and their topographical changes were identified using scanning electron microscope. Results: there was no significant difference in Ra values between the two ceramic types before and after surface treatment. There was no significant difference in Ra values between the two surface treatments on both ceramics. There was a difference in the effect of the surface treatments on the topography of the ceramics Conclusion: Both surface treatments have comparable effect on the surface roughness of lithium disilicate ceramic but have different effect on the ceramic's topography.

Brazilian Dental Science, Mar 31, 2020

Objective: To evaluate and compare the wear behavior of three different ceramic systems; monolith... more Objective: To evaluate and compare the wear behavior of three different ceramic systems; monolithic zirconia, lithium di-silicate and nano-fluorapatite glass ceramic with two finishing procedures polishing and glazing, and their effect on the wear of natural tooth antagonists. Material and Methods: Forty two ceramic disc specimens (10mm x3mm) and forty two natural tooth antagonists were used. Samples were divided according to ceramic materials into 3 groups (n = 14). Group I: nano-fluorapatite glass ceramic (FLU) (IPS e.max Ceram), Group II: lithium disilicate (LD) (IPS e.max CAD) and group III: monolithic zirconia (ZIR) (ZirkoZahn Prettau). Each group was further subdivided into two subgroups (n = 7), according to the surface finish: Polishing (P) and glazing (G). Specimens were subjected to a custom designed two-body wear simulator. Quantitative wear assessment was carried out using weight loss measurements. Scanning electron microscope was used for characterization of wear patterns. Kruscal Wallis and Dunn's tests were used to compare between weight loss of the three ceramic materials. Whitney U test was used to compare the weight loss between the two surface finish protocols. Wilcoxon Signed rank test was used to compare the weight loss between ceramic specimens and antagonist teeth (p ≤ 0.05). Paired t-test was used to compare weight loss before and after wear test. Results: After wear, LD and FLU had the highest weight loss values compared to ZIR (p < 0.05). For teeth, there was no significant difference between the weight loss values with the three materials (p > 0.05). P and G specimens showed no significant difference in weight loss values. SEM images of the wear patterns verified the previous analysis. Conclusion: ZIR is more wear resistant than LD and FLU. However, the surface treatment had no impact on the wear behavior. Comportamento do desgaste da zircônia monolítica frente a dentes naturais em comparação com duas cerâmicas de vidro com diferentes protocolos de acabamento superficial: um estudo in vitro

Brazilian Dental Science, Mar 31, 2020

Objective: The purpose of the study was to evaluate the effect of different preparation designs a... more Objective: The purpose of the study was to evaluate the effect of different preparation designs and different surface treatments on the fracture resistance of monolithic zirconia inlay-retained fixed dental prosthesis [IRFDP]. Material and methods: Forty-five translucent zirconia IRFDPs were divided into three groups according to preparation designs (n = 15); group I: proximal box, group II: inlay-box and group III: butterfly wing (modified inlay). Each group was further subdivided into three subgroups according to the surface treatments utilized (n = 5); sandblasting, tribochemical silica coating (Cojet system) and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser irradiation. All zirconia IRFDPs were cemented to their respective resin models using selfadhesive resin cement. All cemented IRFDPs were subjected to fracture resistance test using universal testing machine. The initial fracture site was determined by using a stereomicroscope (x6.7magnification). Two-way analysis of variance (ANOVA) was used to evaluate the effect of different designs, different surface treatments and their interaction on the mean fracture resistance. Bonferroni's post-hoc test was used when ANOVA is significant (P ≤ 0.05). Results: Butterfly wings design showed the highest fracture resistance values followed by inlay and box designs respectively (P ≤ 0.05). Sandblasting and Cojet showed significantly the highest mean fracture resistance values than Laser with no significance difference between them. Conclusion: The butterfly wing design increased the fracture resistance of the zirconia IRFDPs. Sandblasting and tribochemical silica coating of zirconia surfaces had a greater effect than Er, Cr: YSGG laser to gain higher fracture resistance of zirconia IRRDPs. Carga até falha de três diferentes desenhos de inlays de zircônia monolítica com três tratamentos de superfície

Background: Shade selection in the appearance zone is a challenge for laboratory technicians and ... more Background: Shade selection in the appearance zone is a challenge for laboratory technicians and clinician. Knowing the prevalence of tooth shade among a specific population can help in proper tooth selection in fixed Prosthodontics. Objective: This study was designed to identify the most prevalent shade among sample of Egyptian participants who receive their treatment in Misr International University dental clinic analyzing different age and gender. Material and methods: A convenience sample of 180 subjects was recruited at MIU dental clinic and divided into three equal groups according to age (n=60): young group (18-30 years old), middle-aged group (31-59 years old) and elderly group (over 60 years old). Each group was further subdivided into two equal subgroups according to gender (male /female) (n=30). shade recording was carried using a spectrophotometer (3D master Easyshade Compact; Vita Zahnfabrik). Chi-square and spearman’s correlation coefficient were used to determine the...

Brazilian Dental Science

Objective: the purpose of the study was to evaluate the micro-shear bond strength of different ce... more Objective: the purpose of the study was to evaluate the micro-shear bond strength of different cements to translucent zirconia before and after thermocycling aging. Material and methods: Twelve translucent zirconia ceramic discs were used in the study. Specimens were sandblasted using 50 ‎μm aluminum oxide (Al2O3) particles. The specimens were divided into three groups (n = 4) according to the cement type: Panavia resin cement (control group), resin modified glass ionomer (RMGI), and Activa bioactive cement. Each group was further sub-divided into two equal subgroups (n = 2) according to whether the specimens were subjected to thermocycling or not. Thermocycling was performed in distilled water at 5000 cycles between 5oC-55oC. The micro-shear bond strength test (μSBS) was measured using universal testing machine. Kruskal-Wallis test was used to compare between the three cements. Dunn’s test was used for pair-wise comparisons when Kruskal-Wallis test is significant. Mann-Whitney U te...

Brazilian Dental Science

Objective: To evaluate the marginal fit and microleakage of monolithic zirconia crowns cemented w... more Objective: To evaluate the marginal fit and microleakage of monolithic zirconia crowns cemented with bioactive cement (Ceramir) compared to that cemented with glass ionomer cement and to evaluate the effect of thermocycling on marginal fit. Materials and methods: Twenty sound human molar teeth were prepared to receive a monolithic zirconia crowns. Teeth were divided randomly into two equal groups according to the type of luting cement. Group I: glass ionomer cement and group II: Ceramir cement. After cementation, the vertical marginal gap was assessed by using stereomicroscope before and after thermocycling. Twenty equidistant measurement points were taken for each crown. Leakage assessment was carried out using Fuchsin dye penetration followed by digital photography under a stereomicroscope. Data were analyzed by Mann-Whitney U test to compare between the two luting cements. Wilcoxon signed-rank test was used to evaluate the effect of thermocycling on the marginal fit (P ≤ 0.05) Re...

Stomatological Disease and Science

The purpose of this in vitro study was to determine the optimum margin thickness which allows mor... more The purpose of this in vitro study was to determine the optimum margin thickness which allows more conservative tooth preparation, thus giving space for the veneer material and to evaluate the effect of the processing technique on fracture resistance of IPS e.max ® copings. Methods: Forty all lithium disilicate copings were divided into 2 equal groups according to the construction technique; twenty copings each (n = 20) per group. Each group was further subdivided into 2 equal subgroups according to the coping margin thickness; 0.5 mm and 0.7 mm (n = 10/subgroup). Two dies were prepared with 5 mm cervical diameter, 60° axial taper, and 5 mm occluso-cervical height with the non-anatomical occlusal table. Copings were constructed using heat pressing and CAD/CAM milling techniques, and were cemented on epoxy dies using RelyX™ Unicem resin cement. Samples underwent pre-loading in a cyclic manner equivalent to the average masticatory cycle. Afterward, samples were loaded until fracture using the same computer controlled material testing machine. Data were analyzed for each group using one-way analysis of variance (ANOVA) followed by a Tukey's pairwise post-hoc test between the 2 coping thicknesses. P values which were 0.05 or less were considered statistically significant. Separate student t-tests was performed to detect the significance between the main groups. Finally, a two-way ANOVA was done to evaluate the effect of the processing technique, and the coping thickness on the fracture resistance. Results: Effect of the construction technique revealed significant (P < 0.05) influence on the

European Journal of Dentistry, 2014

Objective: To investigate the repair potential of CAD/CAM (computer-aided design/computer-aided m... more Objective: To investigate the repair potential of CAD/CAM (computer-aided design/computer-aided manufacturing) ceramic and composite blocks using a silane-containing bonding agent with different repair protocols. Materials and Methods: Twenty-four discs were constructed from CAD/CAM ceramic and composite blocks. The discs were divided into six groups according to surface pre-treatment employed; GI: Diamond stone roughening (SR), GII: SR+ silanization (SR+S), GIII: Hydrofluoric acid etching (HF), GIV: HF+ silanization (HF+S), GV: Silica coating (SC), GVI: SC+ silanization (SC+S). Silane-containing bonding agent (Single Bond Universal adhesive, 3M ESPE) was applied to the pre-treated discs. Prior to light curing, irises were cut from tygon tubes (internal diameter = 0.8 mm and height = 0.5 mm) and mounted on each treated surface. Nanofilled resin composite (Filtek Z350XT, 3M ESPE) was packed into the cylinder lumen and light-cured (n = 10). The specimens were subjected to microshear b...

Deleted Journal, Mar 1, 2024

The study aims to assess the influence of hydrothermal aging on gradient zirconia's microstructur... more The study aims to assess the influence of hydrothermal aging on gradient zirconia's microstructure and color stability. Materials and methods: Ten discs were constructed from gradient zirconia blanks (3Y-TZP-5Y-TZP) using CAD\CAM technology. Hydrothermal aging was done in an autoclave. Color parameters (a*, b*, L*) for each disc was measured using a spectrophotometer. In order to investigate the zirconia specimens' crystalline structure, X-ray diffraction (XRD) was performed. Color stability and microstructural changes were examined before and after the aging process. Results: Following hydrothermal aging, a statistically significant decrease in the mean (L*) value was found. However, following hydrothermal aging, a statistically significant increase in the mean (a*) and (b*) values was reported. Regarding the microstructure, hydrothermal aging did not result in any significant changes. Conclusion: Artificial aging has led to color changes in gradient zirconia that were in the clinical acceptability range but has no impact on the microstructure of gradient zirconia.

Statement of Problem With the rise of an esthetic demand for a more natural mimic appearance zirc... more Statement of Problem With the rise of an esthetic demand for a more natural mimic appearance zirconia bridges and frame works are becoming more and more recommended. Having an esthetic strong restoration as zirconia IRFPD is a better option than the aggressive full coverage restoration or a long, painful and expensive procedure as implant retained restoration. Aim of the study is to examine the impact of cyclic loading and two distinct surface treatments modalities on the marginal fit of different designs of Inlay retained fixed partial denture cemented with an MPD containing resin cement. Materials and methods 30 IRFPD were constructed from zirconia with three designs [box, inlay box and winged inlay box] n=10. The samples were split into two subgroups within each group based on the type of surface treatment they received. [sandblasting, Air borne salinization] n=5. IRFPD's were cemented and examined by stereomicroscope for marginal adaptation before and after cyclic loading. Results surface treatments and cyclic loading had significant effect on marginal adaptation of IRFPD's whereas the different design had no significant effect. Conclusion IRFPD is a good alternative to restore missing posterior teeth with application of surface conditioning to zirconia and the use of MDP containing cement.

To evaluate the effect of nanotechnology on bond strength of hybrid ceramics. Twelve CAD/CAM cera... more To evaluate the effect of nanotechnology on bond strength of hybrid ceramics. Twelve CAD/CAM ceramic slices were divided into 3 groups (n=4) (Lava Ultimate [LU], Vita Enamic [VE], and IPS e.max [EM]). Each was subdivided into 2 subgroups (n=2) (hydrofluoric acid etching [HF] and Sandblasting [SB]). Each was subdivided into 2 subdivisions (n=1) (Scotchbond Universal [SbU] and Futurabond U [FbU]). Silane was applied for 1 minute. Five micro-cylinders of RelyX Ultimate were cemented on each slice. 5000 thermocycles were done. Micro-shear bond strength (μSBS) was performed using the universal testing machine. SEM analysis was used to identify the mode of failure and the effect of surface treatment. Surface roughness (Ra) was measured by contact profilometer. Three-way ANOVA was used to study the effect of ceramic material, surface treatment, and universal adhesive on μSBS. Bonferroni’s post-hoc test was used when ANOVA test was significant (P ≤.05). Two-way ANOVA was used to study the effect of ceramic microstructure and surface treatment on surface roughness. LU showed the highest μSBS and the least Ra values. The nanostructure of LU enhanced its bonding properties and decreased its surface roughness. HF and silane application could be considered a reliable surface treatment for bonding of hybrid ceramics. The presence of silane in SbU, in addition to the separate silane application, was enhanced the μSBS of the sandblasted LU.

IOP Conference Series: Materials Science and Engineering

To assess the effect of nano-modification of two CAD/CAM monolithic Zirconia systems (wet and dry... more To assess the effect of nano-modification of two CAD/CAM monolithic Zirconia systems (wet and dry-milled) on microstructural changes and fracture resistance upon aging. Twenty monolithic Zirconia discs (10mm x1.5mm) were divided into 2 groups (n=10) according to fabrication system;wet-milled (Incoris TZI) and dry-milled (CeramillZolid). Each group was subdivided into two subgroups (n=5), whether subjected to aging or not. Aging proceduresincluded accelerated hydrothermal aging and cyclic loading. Microstructural changes were assessed quantitatively and qualitatively using x-ray diffraction (XRD) and scanning electron microscope (SEM) respectively. Discs were subjected to fracture resistance test usinguniversal testing machine. Meansandstandard deviations were recorded for phase transformation (t-m)of Zirconia and repeated ANOVA was used to correlate phase transformation with fracture resistance results (p≤0.05). For aged subgroups, XRD analysis revealed significantly higher phase tr...

Journal of Fundamental and Clinical Research

Background: PEEK is a polymer with lots of significant potentials making it an important candidat... more Background: PEEK is a polymer with lots of significant potentials making it an important candidate in dental applications; however, strong durable bond of PEEK restorations with resin cement is still questionable. Aim: Evaluating the effect of different surface treatment protocols on the bond strength of PEEK surface with resin cement in comparison to Lithium Disilicate ceramic. Methodology: PEEK (P) and Lithium Disilicate discs (LD) were fabricated using CAD/CAM technique. A total of 40 samples were divided into four groups according to surface treatment protocol (n=10): Group (LD): hydrofluoric acid etching followed by silane application. Group (PP): 110 µm alumina particles sandblasting followed by Piranha solution acid etching. Group (PNsi): 110 µm alumina particles sandblasting followed by nano-silica coating and silane coupling agent respectively. Group (PN): 110 µm alumina particles sandblasting followed by nano-silica coating. All specimens underwent thermocycling. All specimens were cemented using universal resin cement. Micro-shear bond strength (μSBS) test was performed using a universal testing machine and the mode of failure was assessed using digital microscope. Surface roughness was assessed before and after surface treatment using optical profilometer. Results: There was no statistically significant difference between (LD) and (PP); both showed the highest (μSBS). No statistically significant difference between (PNsi) and (PN); both showed the lowest (μSBS). However, statistically significant difference was found between (LD, PP) groups and (PNsi, PN) groups. (P-value = 0.028). Conclusion: PP group showed a comparable μSBS results to LD group, whereas, nano-silica coated group showed the lowest bond strength values.

Journal of Fundamental and Clinical Research

Background: Different digital fabrication techniques affect the marginal adaptation of tooth supp... more Background: Different digital fabrication techniques affect the marginal adaptation of tooth supported provisional and final dental prosthesis. However, there is minimal scientific evidence which technique will be effective for producing tooth supported provisional dental prosthesis with predictable marginal fit. Aim of the study: to evaluate the effect of the two CAM fabrication techniques; milling versus 3D printing on the marginal fit of tooth supported restorations. Materials and methods: two abutment teeth of a modified typodont with a missing left mandibular first molar were prepared to receive a ceramic FDP. A master reference stone model was then, constructed. An optical impression (STL file) of the reference model was taken. A provisional tooth supported FDP was designed on the CAD software using the STL file of the reference model. Eight Restorations were fabricated by different CAM techniques. The restorations were divided into two groups according to the fabrication method; group A (milled restorations) (n=4) and group B (3D printed restorations) (n=4). Finally, the marginal fit of the provisional dental prosthesis was assessed by a stereo optical microscope on the stone reference model. Mann-Whitney U test was used to compare between the two groups. The significance level was set at P ≤ 0.05. Results: the results showed that there was no statistically significant difference between the vertical marginal gap values of the two tested groups. Conclusion: The vertical marginal gap values of provisional restorations fabricated by the two tested methods of manufacturing were comparable and within the acceptable range of 120 µ.

Polymers

Background: Minimal evidence exists on the efficacy of different digital manufacturing techniques... more Background: Minimal evidence exists on the efficacy of different digital manufacturing techniques in the fabrication of precise dental working models and provisional prosthesis. Aim of study: The objective was to evaluate the effect of two digital fabrication techniques (CAD/CAM milling and 3D printing) on the accuracy of PMMA working models and marginal fit of PMMA provisional prosthesis. Materials and methods: Two abutment teeth of modified typodont were prepared. A reference stone model was fabricated, and an optical impression was performed to obtain a CAD reference model. Four CAM milled working models and four printed working models were fabricated. CAD software was used to design the provisional prostheses. Group A tested four milled provisional prosthesis, and group B tested four 3D printed prosthesis. The 3D accuracy of working models was assessed by superimposition of the control reference working model on the CAD test working model. A stereo-optical microscope was used to...

Journal of Oral Implantology, 2013

This study evaluated the effect of fabrication techniques and cyclic loading on the vertical marg... more This study evaluated the effect of fabrication techniques and cyclic loading on the vertical marginal fit of implant-supported fixed partial denture (FPD) frameworks. Thirty implant-supported 3-unit FPD frameworks were fabricated on a model system, divided into 3 equal groups (n = 10). The first group (control) was constructed from base metal alloy; the other 2 test groups were constructed from all-ceramic zirconia using a computer-aided design/computer-aided manufacturing (CAD/CAM) Cerec 3 system and a copy milling (Zirkonzahn) system. A cyclic load of 200 N was applied to each framework for up to 50,000 cycles. Linear measurements were made in micrometers of the vertical gap between the framework and the implant-supported abutment at 16 predetermined points before and after cyclic loading. The frameworks were viewed using scanning electron microscopy to inspect any fractographic features. One-way analysis of variance was performed to compare the marginal discrepancy values of the ...

Brazilian Dental Journal

The aim of this study was to evaluate the survival of laminate veneers constructed using a recent... more The aim of this study was to evaluate the survival of laminate veneers constructed using a recent polymer-infiltrated ceramic network material following the aesthetic pre-evaluative temporary (APT) technique of tooth preparation in comparison to traditional technique. Six patients received 54 laminate veneers. They were divided into two equal groups (n=27) according to the technique of tooth preparation: group T: traditional technique and group A: aesthetic pre-evaluative temporary technique. VITA ENAMIC material was used for CAD/CAM construction of laminate veneers. Cementation was performed using a light cured resin cement. The laminate veneers were evaluated at baseline, after 3, 6 and 12 months according to the modified United States Public Health Service (USPHS) criteriea. The data was collected, tabulated and statistically analyzed. Secondary caries, endodontic complications, cracks and loss of retention were not noted in any laminate veneer. Extensive fractures were not detec...

Egyptian Dental Journal

Objective: To assess the effect of two surface treatment protocols of two pressable lithium disil... more Objective: To assess the effect of two surface treatment protocols of two pressable lithium disilicate ceramics with different thicknesses on the surface roughness and topography. Material and methods: Sixty four lithium disilicate ceramic discs were divided into two groups (n=32); IPS e.max Press and Initial TM LiSi Press. Each group was subdivided into two subgroups (n=16) according to thicknesses (0.5mm and 1mm). Each subgroup was divided into two subdivisions (n=8) according to the surface treatment; Er:Cr:YSGG Laser and hydrofluoric acid etching. Artificial aging was performed for all the specimens. Surface roughness (Ra) before and after surface treatment protocol was measured using contact stylus profilometer and their topographical changes were identified using scanning electron microscope. Results: there was no significant difference in Ra values between the two ceramic types before and after surface treatment. There was no significant difference in Ra values between the two surface treatments on both ceramics. There was a difference in the effect of the surface treatments on the topography of the ceramics Conclusion: Both surface treatments have comparable effect on the surface roughness of lithium disilicate ceramic but have different effect on the ceramic's topography.

Brazilian Dental Science, Mar 31, 2020

Objective: To evaluate and compare the wear behavior of three different ceramic systems; monolith... more Objective: To evaluate and compare the wear behavior of three different ceramic systems; monolithic zirconia, lithium di-silicate and nano-fluorapatite glass ceramic with two finishing procedures polishing and glazing, and their effect on the wear of natural tooth antagonists. Material and Methods: Forty two ceramic disc specimens (10mm x3mm) and forty two natural tooth antagonists were used. Samples were divided according to ceramic materials into 3 groups (n = 14). Group I: nano-fluorapatite glass ceramic (FLU) (IPS e.max Ceram), Group II: lithium disilicate (LD) (IPS e.max CAD) and group III: monolithic zirconia (ZIR) (ZirkoZahn Prettau). Each group was further subdivided into two subgroups (n = 7), according to the surface finish: Polishing (P) and glazing (G). Specimens were subjected to a custom designed two-body wear simulator. Quantitative wear assessment was carried out using weight loss measurements. Scanning electron microscope was used for characterization of wear patterns. Kruscal Wallis and Dunn's tests were used to compare between weight loss of the three ceramic materials. Whitney U test was used to compare the weight loss between the two surface finish protocols. Wilcoxon Signed rank test was used to compare the weight loss between ceramic specimens and antagonist teeth (p ≤ 0.05). Paired t-test was used to compare weight loss before and after wear test. Results: After wear, LD and FLU had the highest weight loss values compared to ZIR (p < 0.05). For teeth, there was no significant difference between the weight loss values with the three materials (p > 0.05). P and G specimens showed no significant difference in weight loss values. SEM images of the wear patterns verified the previous analysis. Conclusion: ZIR is more wear resistant than LD and FLU. However, the surface treatment had no impact on the wear behavior. Comportamento do desgaste da zircônia monolítica frente a dentes naturais em comparação com duas cerâmicas de vidro com diferentes protocolos de acabamento superficial: um estudo in vitro

Brazilian Dental Science, Mar 31, 2020

Objective: The purpose of the study was to evaluate the effect of different preparation designs a... more Objective: The purpose of the study was to evaluate the effect of different preparation designs and different surface treatments on the fracture resistance of monolithic zirconia inlay-retained fixed dental prosthesis [IRFDP]. Material and methods: Forty-five translucent zirconia IRFDPs were divided into three groups according to preparation designs (n = 15); group I: proximal box, group II: inlay-box and group III: butterfly wing (modified inlay). Each group was further subdivided into three subgroups according to the surface treatments utilized (n = 5); sandblasting, tribochemical silica coating (Cojet system) and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser irradiation. All zirconia IRFDPs were cemented to their respective resin models using selfadhesive resin cement. All cemented IRFDPs were subjected to fracture resistance test using universal testing machine. The initial fracture site was determined by using a stereomicroscope (x6.7magnification). Two-way analysis of variance (ANOVA) was used to evaluate the effect of different designs, different surface treatments and their interaction on the mean fracture resistance. Bonferroni's post-hoc test was used when ANOVA is significant (P ≤ 0.05). Results: Butterfly wings design showed the highest fracture resistance values followed by inlay and box designs respectively (P ≤ 0.05). Sandblasting and Cojet showed significantly the highest mean fracture resistance values than Laser with no significance difference between them. Conclusion: The butterfly wing design increased the fracture resistance of the zirconia IRFDPs. Sandblasting and tribochemical silica coating of zirconia surfaces had a greater effect than Er, Cr: YSGG laser to gain higher fracture resistance of zirconia IRRDPs. Carga até falha de três diferentes desenhos de inlays de zircônia monolítica com três tratamentos de superfície

Background: Shade selection in the appearance zone is a challenge for laboratory technicians and ... more Background: Shade selection in the appearance zone is a challenge for laboratory technicians and clinician. Knowing the prevalence of tooth shade among a specific population can help in proper tooth selection in fixed Prosthodontics. Objective: This study was designed to identify the most prevalent shade among sample of Egyptian participants who receive their treatment in Misr International University dental clinic analyzing different age and gender. Material and methods: A convenience sample of 180 subjects was recruited at MIU dental clinic and divided into three equal groups according to age (n=60): young group (18-30 years old), middle-aged group (31-59 years old) and elderly group (over 60 years old). Each group was further subdivided into two equal subgroups according to gender (male /female) (n=30). shade recording was carried using a spectrophotometer (3D master Easyshade Compact; Vita Zahnfabrik). Chi-square and spearman’s correlation coefficient were used to determine the...

Brazilian Dental Science

Objective: the purpose of the study was to evaluate the micro-shear bond strength of different ce... more Objective: the purpose of the study was to evaluate the micro-shear bond strength of different cements to translucent zirconia before and after thermocycling aging. Material and methods: Twelve translucent zirconia ceramic discs were used in the study. Specimens were sandblasted using 50 ‎μm aluminum oxide (Al2O3) particles. The specimens were divided into three groups (n = 4) according to the cement type: Panavia resin cement (control group), resin modified glass ionomer (RMGI), and Activa bioactive cement. Each group was further sub-divided into two equal subgroups (n = 2) according to whether the specimens were subjected to thermocycling or not. Thermocycling was performed in distilled water at 5000 cycles between 5oC-55oC. The micro-shear bond strength test (μSBS) was measured using universal testing machine. Kruskal-Wallis test was used to compare between the three cements. Dunn’s test was used for pair-wise comparisons when Kruskal-Wallis test is significant. Mann-Whitney U te...

Brazilian Dental Science

Objective: To evaluate the marginal fit and microleakage of monolithic zirconia crowns cemented w... more Objective: To evaluate the marginal fit and microleakage of monolithic zirconia crowns cemented with bioactive cement (Ceramir) compared to that cemented with glass ionomer cement and to evaluate the effect of thermocycling on marginal fit. Materials and methods: Twenty sound human molar teeth were prepared to receive a monolithic zirconia crowns. Teeth were divided randomly into two equal groups according to the type of luting cement. Group I: glass ionomer cement and group II: Ceramir cement. After cementation, the vertical marginal gap was assessed by using stereomicroscope before and after thermocycling. Twenty equidistant measurement points were taken for each crown. Leakage assessment was carried out using Fuchsin dye penetration followed by digital photography under a stereomicroscope. Data were analyzed by Mann-Whitney U test to compare between the two luting cements. Wilcoxon signed-rank test was used to evaluate the effect of thermocycling on the marginal fit (P ≤ 0.05) Re...

Stomatological Disease and Science

The purpose of this in vitro study was to determine the optimum margin thickness which allows mor... more The purpose of this in vitro study was to determine the optimum margin thickness which allows more conservative tooth preparation, thus giving space for the veneer material and to evaluate the effect of the processing technique on fracture resistance of IPS e.max ® copings. Methods: Forty all lithium disilicate copings were divided into 2 equal groups according to the construction technique; twenty copings each (n = 20) per group. Each group was further subdivided into 2 equal subgroups according to the coping margin thickness; 0.5 mm and 0.7 mm (n = 10/subgroup). Two dies were prepared with 5 mm cervical diameter, 60° axial taper, and 5 mm occluso-cervical height with the non-anatomical occlusal table. Copings were constructed using heat pressing and CAD/CAM milling techniques, and were cemented on epoxy dies using RelyX™ Unicem resin cement. Samples underwent pre-loading in a cyclic manner equivalent to the average masticatory cycle. Afterward, samples were loaded until fracture using the same computer controlled material testing machine. Data were analyzed for each group using one-way analysis of variance (ANOVA) followed by a Tukey's pairwise post-hoc test between the 2 coping thicknesses. P values which were 0.05 or less were considered statistically significant. Separate student t-tests was performed to detect the significance between the main groups. Finally, a two-way ANOVA was done to evaluate the effect of the processing technique, and the coping thickness on the fracture resistance. Results: Effect of the construction technique revealed significant (P < 0.05) influence on the

European Journal of Dentistry, 2014

Objective: To investigate the repair potential of CAD/CAM (computer-aided design/computer-aided m... more Objective: To investigate the repair potential of CAD/CAM (computer-aided design/computer-aided manufacturing) ceramic and composite blocks using a silane-containing bonding agent with different repair protocols. Materials and Methods: Twenty-four discs were constructed from CAD/CAM ceramic and composite blocks. The discs were divided into six groups according to surface pre-treatment employed; GI: Diamond stone roughening (SR), GII: SR+ silanization (SR+S), GIII: Hydrofluoric acid etching (HF), GIV: HF+ silanization (HF+S), GV: Silica coating (SC), GVI: SC+ silanization (SC+S). Silane-containing bonding agent (Single Bond Universal adhesive, 3M ESPE) was applied to the pre-treated discs. Prior to light curing, irises were cut from tygon tubes (internal diameter = 0.8 mm and height = 0.5 mm) and mounted on each treated surface. Nanofilled resin composite (Filtek Z350XT, 3M ESPE) was packed into the cylinder lumen and light-cured (n = 10). The specimens were subjected to microshear b...