Cherif Mohsen - Academia.edu (original) (raw)
Papers by Cherif Mohsen
Upper Egypt Critical Care Journal, Mar 21, 2024
Egyptian dental journal, Oct 1, 2022
Purpose: The ultimate appearance of all ceramic restorations is significantly influenced by color... more Purpose: The ultimate appearance of all ceramic restorations is significantly influenced by color and translucency. The performance of the restoration is significantly influenced by flexural strength. This study's objective was to assess how various shading methods affected the color, translucency, and flexural strength of monolithic zirconia ceramic as it aged. Materials and Methods: Thirty zirconia discs with a diameter of 12mm and thickness of 1mm were divided into two groups of 15 discs each according to the technique of shading, the first group was constructed from A2 pre-shaded zirconia while the second group was constructed from unshaded zirconia that was shaded by immersion in A2 coloring liquid. Aging was done using acetic acid 4% for both groups. Color and translucency were measured using a spectrophotometer before and after artificial aging. Flexural strength was measured using a universal testing machine before and after aging. Data were collected, tabulated, and statistically analyzed. Results: Color change of both pre-shaded and liquid-shaded zirconia were within the clinically acceptable range (1.7±0.3) and (1.9±0.3) respectively and there was no significant difference in translucency between both groups' P value (0.253). Flexural strength increased from (921.9±73.3) before aging to (1025.1±178.5) after aging with pre-shaded zirconia while it decreased from (938.6±32.7) before aging too (899±54.5) after aging with liquid shaded zirconia but this difference was statistically non-significant. Conclusion: The shading technique had no noticeable effect on color, translucency, or flexural strength before or after aging.
International Journal of Health Sciences (IJHS), Mar 22, 2022
The purpose of this study was to assess the effect of Nano-silica Coating on the Color and the Mi... more The purpose of this study was to assess the effect of Nano-silica Coating on the Color and the Microleakage of Zirconia Ceramics. Materials and methods: Eighty-five specimens of commercially available Yttrium-stabilized-zirconia ceramics were constructed and divided into forty-five discs (8 mm in diameter) with thickness (1.2mm) They were divided into three groups (thermocycling-nano-silica surface treatment-and thermocycling with nano-silica surface treatment) to assess the color parameters, while the other forty samples were divided into (control group-thermocyclingnano-silica surface treatment-and thermocycling with nano-silica surface treatment) to perform a fully contoured crowns to assess the microleakage. Initial color measurements were taken using a digital spectrophotometer based on CIE L*a*b* color system using a spectrophotometer Standard permanent molar tooth preparation was conducted into a full veneer preparation. Nano silica sol-gel material painted on the fitting surface of zirconia ceramics in groups of nanosilica and nano-silica with thermocycling surface treatment and processed to firing that were finally cemented on the prepared teeth using resin adhesive luting agent. Samples in aged group were subjected to 5000 thermal cycles then crown samples were sectioned to measure the microleakage. Color measurements of all samples were measured again.
Journal of cardiovascular disease research, 2021
ure mode pattern according to the following categorization. Results: Regarding the fracture resis... more ure mode pattern according to the following categorization. Results: Regarding the fracture resistance testing, the results of the present study revealed that there was no statistically significant difference between mean fracture resistance values of IPS Emax press (235.54 N) and Celtra press; (244.98 N) where both showed statistically non-significant highest mean fracture resistance. Conclusion: The results obtained in this study revealed a non-significant difference between the endocrown restorations and the post and core and crown. Although endocrown showed higher fracture resistance values compared to the post and core and crown. Also the results showed non-significant difference between the endocrown restorations with different designs. Although endocrown (10 mm) showed higher fracture resistance values than endocrown (6 mm) which may be due to an increase in surface area.
Open Journal of Stomatology, 2011
Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay re... more Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were constructed and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-proximal inlay + proximal box), tub-shaped (occluso-proximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shaped inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was significant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant difference than the other two inlay retained FPDs designs. Conclusions: There was no significant difference between full coverage FPDs, tub-shaped & proximal box shaped inlay retained FPDs as regard vertical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrepancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical marginal discrepancies were in the range of clinical acceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs designs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay retained FPDs designs. There was no difference as regard retentive strengths between tub-shaped & proximal box shaped inlay retained FPDs.
Egyptian Dental Journal
Objective The goal of this study was to find out how aging and a surface treatment called solgel ... more Objective The goal of this study was to find out how aging and a surface treatment called solgel nano silica affect microleakage in zirconia ceramic crowns. Materials and methods: Twenty recently extracted human maxillary first molars were prepared for full coverage zirconia crowns made of Yttrium-stabilized zirconia ceramics that are readily available. They were split into four groups, each with five samples the control group, the thermocycling group, the nanosilica group, and the nanosilica-thermocycling group. Zirconia crown fitting surfaces were coated with a sol-gel nano silica substance. Thermal cycling was performed 5000 thermal cycles. TheraCem resin cement was used to cement all of the crowns. Crowns were submerged in 0.5% methylene blue solution for 24 hours before being sectioned bucco-lingually for microleakage testing. The depth of dye penetration was evaluated using a light stereomicroscope (Nikon MA100 Japan) at 50 magnification and image analysis software (Omnimet, Buchler, USA). The Tukey test and one-way ANOVA were used for statistical analysis. Result: The nanosilica group had the lowest microleakage, followed by the nano-silica with thermocycling group. Among the groups, the thermocycling group had the highest microleakage values. Conclusion: Although sol-gel nano silica coating reduces microleakage, ageing has a negative impact on it.
Egyptian Dental Journal
Objective: The aim of this study is to evaluate the effect of ceramic repressing on internal fit ... more Objective: The aim of this study is to evaluate the effect of ceramic repressing on internal fit of two different pressable ceramic materials. Materials and Methods: Two commercially available glass ceramic materials were used in this study; IPS E-max press (Ivoclar, vivadent) and Celtra press (Dentsply, Sirona). The two materials were used to fabricate veneer samples as which a total of twenty veneers were constructed. The samples for each material(n=10) were randomly divided into two equal groups; Group A: Pressed specimens (n=5) veneer shaped wax patterns were invested and heat-pressed according to the manufacturer's recommendations and Group B: Repressed specimens (n=5) the leftover material from 1st pressing was recovered and the buttons were adjusted to fabricate the specimens by repeated heat-pressing using the same procedures as for (A The internal gap distance between the veneers and the resin dies substance ware measured with the stereomicroscope at three preselected locations at 70× magnification. Internal fit adaptation was recorded and mean values for each group determined. Data was statistically analyzed. Results: For IPS E.max or Celtra press; there was no statistically significant difference between mean values of press and repress conditions (P <0.05) between tested groups. It was found that internal gab mean values was recorded for Celtra repress recorded (96.6±6.4) μm which was the highest value which gave poorest fit then E-max repress was recorded (92.6±7.6) μm , Celtra press recorded (91.8±2.8) μm, however E-max press recorded (91.6±5.6) μm which was the lowest mean value for internal fit test. Conclusions: The optimum properties for lithium disilicate Press ceramic materials are obtained with the first pressing. However the microstructure and mechanical characteristics could be impacted by numerous heat repressions, but there would be no statistically significant change in how the internal fit would adjust.
International journal of health sciences, 2022
Objective The purpose of this study was to assess the effect of Nano-silica Coating on the Color ... more Objective The purpose of this study was to assess the effect of Nano-silica Coating on the Color and the Microleakage of Zirconia Ceramics. Materials and methods: Eighty-five specimens of commercially available Yttrium-stabilized-zirconia ceramics were constructed and divided into forty-five discs (8 mm in diameter) with thickness (1.2mm) They were divided into three groups (thermocycling – nano-silica surface treatment – and thermocycling with nano-silica surface treatment) to assess the color parameters, while the other forty samples were divided into ( control group – thermocycling – nano-silica surface treatment – and thermocycling with nano-silica surface treatment) to perform a fully contoured crowns to assess the microleakage. Initial color measurements were taken using a digital spectrophotometer based on CIE L*a*b* color system using a spectrophotometer Standard permanent molar tooth preparation was conducted into a full veneer preparation. Nano silica sol-gel material pain...
INTRODUCTION Endodontically treated teeth restoration is compromised primarily because increased ... more INTRODUCTION Endodontically treated teeth restoration is compromised primarily because increased risk of coronal destruction that results in tooth fracture during function. Before the introduction of adhesion in dentistry, the coronal restoration endodontially treated teeth has been mainly performed with metallic and macro mechanically retained posts. In the past, a length of post equal to three fourths of the root canal or at least equal to the crown length (Goodacre CJ, Spolnik KJ, 1995; Abramovitz L, et al., 2001). A restorative option for endodontically treatment an endocrown is. It consists of a full crown that extends a post into the pulp chamber and/ or pulp canals as one unit (Lander E and Dietschi D, 2008). One of option to restore severe destructed, supragingival structure of posterior teeth (Stockton L, et al., 1998) endocrown. These restorations are the most prevalent in case of damaged molars crowns, narrow and short roots, obturated canals or limited interocclusal spac...
Neuroquantology, May 10, 2022
Objective: The aim of this study is to evaluate the retention of lithium disilicate crowns cement... more Objective: The aim of this study is to evaluate the retention of lithium disilicate crowns cemented by resin cement on zirconia and titanium implant abutments coated with glycerin and eugenol. Materials and Methods: Forty implant analogs were embedded in forty blocks of epoxy resin. Twenty implant analogs received a zirconia implant abutment to which 20 IPS e.max press crowns were cemented. The other twenty implant analogs received a titanium implant abutment to which 20 IPS e.max press crowns were cemented. According to the cementation technique, the samples were subdivided into two groups, 10 samples each. In Gp A, zirconia implant abutments’ surfaces were coated with a single coat of eugenol before cementing crowns with the permanent resin luting cement. In Gp B, same as in Gp B with replacement of eugenol with single coat of glycerin. In Gp C, Titanium implant abutments’ surfaces were coated with a single coat of eugenol before cementing crowns with the permanent resin luting cement. In Gp D, same as in Gp C with replacement of eugenol with single coat of glycerin. Each sample was subjected to a pull-out test. Loads required to remove the crowns were recorded, and mean values for each group determined. Data were statistically analyzed. Results: The mean values ±SD of loads at failure (n -10) for each group were as follows in Newton (N): Group(A) 141.9±17.9, Group(B) 134±14.5, Group(C) 140.5±17, Group(D) 143.6±12.4. All groups showed statistically insignificant difference in retention (p<0.05). Conclusions: There was no significant difference between eugenol and glycerin coated zirconia implant abutments in retention of lithium disilicate crowns. There was no significant difference between eugenol and glycerin coated titanium implant abutments in retention of lithium disilicate crowns.
Open Access Macedonian Journal of Medical Sciences
AIM: The focus of this research was to see how silica nanoparticles changed veneering porcelain o... more AIM: The focus of this research was to see how silica nanoparticles changed veneering porcelain over a zirconia core affected flexure strength, shear bond strength, and color. METHODS: A total number of 30 zirconia core veneer samples were constructed and classified according to silica nanoparticles modification of veneering porcelain into two groups: Group 1 (control group) veneering porcelain without any modification (n = 15) and Group 2 (modified group) veneering porcelain modified by silica nanoparticles (n = 15). Silica nanoparticles were added to the veneering porcelain powder at a rate of 5% by weight. Silica nanoparticles powder and veneering porcelain powder were manually crushed for about 10 min using a pestle and mortar then the mixed powder was combined with the porcelain moldings liquid to make a paste. After thermal cycling, each group was examined for flexural strength, shear bond strength, and color measurement (n = 5). Universal testing equipment was used to determi...
Open Access Macedonian Journal of Medical Sciences
BACKGROUND: The color of all ceramic restorations has a significant effect on the final appearanc... more BACKGROUND: The color of all ceramic restorations has a significant effect on the final appearance of the restoration. AIM: This study aimed to evaluate the effect of different shading techniques on the color stability of monolithic zirconia crowns cemented on the upper anterior teeth. METHODS: In this study, there were nine patients. Each patient has undergone a reduction for the upper six anterior teeth. Fifty-four zirconia jacket crowns were constructed using CAD/CAM technique. According to the shading technique, the crowns were categorized into two groups (pre-shaded and liquid shaded), where the upper right reduced teeth received pre-shaded zirconia crowns while the upper left reduced teeth received liquid-shaded zirconia crowns according to the selected shade. The color was assessed using easy shade after cementation and 1 year follow-up period. Data were collected, tabulated, and statistically analyzed. RESULTS: Color change (ΔE) of the cemented pre-shaded zirconia crowns on ...
Systematic Reviews in Pharmacy, 2021
Objective: The purpose of this in vitro study will evaluate marginal gap of endocrowns retained b... more Objective: The purpose of this in vitro study will evaluate marginal gap of endocrowns retained bridges replacing missing lower second molar will done by two different designs from monolithic zirconia. Material and method: twenty bridges designed from monolithic zirconia. Specimens will be divided into two groups, each of these groups contains 10 samples, the first group represents endocrown endocrown retained, and second group endocrown retained bridges. The marginal gap for the buccal, lingual, proximal and connector area were measured .scan electron microscope were used. Universal testing machine was used to detect fracture resistance for all samples. Results: Data analysis was performed by student t-tests to detect significance between groups. One way analysis of variance ANOVA test followed by pair-wise Newman-Keuls was used to detect significance between sites. Statistical analysis was performed using Graph pad Prism-4 statistics software for Windows. P values 0.05). Conclusio...
Aim: The purpose of this study is to evaluate the effect of surface treatments on color of lithiu... more Aim: The purpose of this study is to evaluate the effect of surface treatments on color of lithium disilicate ceramic (IPS e. max [CAD]) and hybrid ceramic (VITA Suprinity [pc]). Method: Ceramic blocks were sectioned in to one hundred sixty discs; eighty discs of lithium disilicate were randomly subdivided in to four groups according to surface treatment (n= 20). Group C: Control group without surface treatment; group I: using (AL2O3) particles size 50μm; group II: Hydro fluoric (HF) acid etching; group III: tribochemical (TBC) surface treatment. Eighty discs of hybrid ceramic (n= 20) were subdivided in to the same groups. Color measurements were performed with spectrophotometer and repeated after surface treatments. ∆E values were statistically analyzed with oneway ANOVA, Tukey's post hoc test was done to identify significance between groups. Statistically significance was considered when P value ≤ 0.05. Results: Changing color of lithium disilicate specimens were not clinicall...
Objectives: The presence of fine-grained crystals of lithium silicate, which contains a high amou... more Objectives: The presence of fine-grained crystals of lithium silicate, which contains a high amount of glass provides the material it’s optical and mechanical characteristics. This unique microstructure allows this material to be processed in a dental lab quickly and efficiently in its crystalline state and the exact tooth shade. This study aims to evaluate the color stability of zirconia reinforced lithium silicate ceramic and lithium disilicates ceramic restorations. Materials and Methods: In this in vitro study, 40 discs of 2mm thickness and 10mm in diameter would be fabricated, all samples were divided into two groups (n=20) according to ceramic material used: group Z zirconia reinforced lithium silicates ceramic(ZLS) and group L lithium disilicate ceramic(LS) discs. Each group was subdivided into two subgroups according to the aging process (n=10) (before and after aging). CIELAB color parameters of all samples were calculated from spectral reflectance measurements on a spectro...
Systematic Reviews in Pharmacy, 2021
Objective: The purpose of this study was to investigate Effect Of Corrosion On Some Properties Of... more Objective: The purpose of this study was to investigate Effect Of Corrosion On Some Properties Of Dental Ceramics. Materials and Method: Twenty four samples were constructed and divided into 3 groups according to ceramic materials used (8 samples for each) group 1(E max), group 2(High Translucent Zirconia (DD BioZx2)) and group 3 (Opaque Zirconia. (DD BioZ)). Then each group was subdivided into three subgroups (3 samples each) according to sequence of tests performed. Then 4 samples from each subgroup were subjected to acetic acid as a corrosive agent. Those samples were first weighted, after that subjected to corrosion test, then weighted again to determine weight loss of each sample. Then samples were tested for color stability using the VITA Easy shade before and after corrosion. shade guides for samples were used (A3). Disinfection methods included immersion for 10 minutes in 1 of the tested disinfectant solutions (5.25% sodium hypochlorite, 2% alkaline gluteraldehyde or 1.7% tr...
Egyptian Dental Journal, 2021
Objective: investigation of the microshear bond strength between lithium disilicate with preheate... more Objective: investigation of the microshear bond strength between lithium disilicate with preheated viscous composite, flowable composite and resin cement by comparison of their microshear bond strength. Material and method: forty five samples were prepared and divided into three groups; preheated viscous composite group, flowable composite group and resin cement group. Materials were injected into custom made plastic transparent molds (2 mm height, 2 mm diameter) on surface of lithium disilicate discs that were previously surface treated with ceramic etchant (hydrofluoric acid 4.5%) and ceramic primer (silane coupling agent). Then, Microshear bond strength test was performed to samples by universal testing machine. Results were tabulated and statistically analyzed for each group. Results: highest microshear bond strength was recorded for preheated viscous composite followed by flowable composite and resin cement. Conclusions: preheated viscous composite is an excellent material in c...
Objective: the purpose of this study was to investigate fracture strength of two types of hybrid ... more Objective: the purpose of this study was to investigate fracture strength of two types of hybrid ceramic posterior occlusal veneers with different thicknesses. Materials and methods: Eighty natural maxillary molars of comparable size and morphology will be selected. Standardization of the teeth preparations will be accomplished using a diamond saw; teeth will be sectioned horizontally, removing all coronal tooth structure 4 mm occlusal to the CEJs leaving exposed dentin centrally and peripheral enamel. Samples will be randomly divided into two groups (n=40) based on restorative materials that will be used: computer-milled hybrid ceramic (ENAMIC) and Resin Nano Ceramic (LAVA ULTIMATE). Each group will be divided into two subgroups (20 samples each) according to the type of preparation (conventional and experimental). The experimental preparation will have an additional preparation feature. Within each subgroup, specimens were subdivided into two classes (consisting of 10 specimens ea...
Objective: investigation of the microshear bond strength between lithium disilicate with preheate... more Objective: investigation of the microshear bond strength between lithium disilicate with preheated viscous composite, flowable composite and resin cement by comparison of their microshear bond strength. Material and method: forty-five samples were prepared and divided into three groups; preheated viscous composite, flowable composite and resin cement. Materials were injected into plastic transparent molds (2 mm height, 2 mm diameter) on the surface of lithium disilicate discs previously surface treated with ceramic etchant (hydrofluoric acid 4.5%) and ceramic primer (silane coupling agent). Microshear bond strength test was performed samples by universal testing machine. Results: highest microshear bond strength was recorded for preheated viscous composite. Conclusions: preheated viscous composite is an excellent material in cementation of lithium disilicate ceramic restorations.
Objectives: Wear assessment of different ceramic restorations placed against different occlusal a... more Objectives: Wear assessment of different ceramic restorations placed against different occlusal antagonists. Materials and methods: Sixty ceramic sample discs (13mm in diameter and 2mm in thickness) were divided into two groups; full contour zirconia (Zr) and lithium disilicate press on zirconia substrate (E.max) discs. Sixty antagonists were constructed and subdivided into three subgroups: (1)Discs wearing against extracted teeth. (2) Discs wearing against Porcelain fused to metal crowns (PFMc). (3)Discs wearing against full contour zirconia crowns (Zrc).Sample discs and antagonists were dynamically three-body loaded in dual axis chewing simulator with 49 N for 75000 loading cycles. Wear measurement for sample discs and antagonist were calculated using height, weight loss,and surface roughness. Data were statistically analyzed with a 2-way analysis, followed by a Tukey test when showed significantly. Student t-test was done between main groups. Results: E.max showed statistically s...
Upper Egypt Critical Care Journal, Mar 21, 2024
Egyptian dental journal, Oct 1, 2022
Purpose: The ultimate appearance of all ceramic restorations is significantly influenced by color... more Purpose: The ultimate appearance of all ceramic restorations is significantly influenced by color and translucency. The performance of the restoration is significantly influenced by flexural strength. This study's objective was to assess how various shading methods affected the color, translucency, and flexural strength of monolithic zirconia ceramic as it aged. Materials and Methods: Thirty zirconia discs with a diameter of 12mm and thickness of 1mm were divided into two groups of 15 discs each according to the technique of shading, the first group was constructed from A2 pre-shaded zirconia while the second group was constructed from unshaded zirconia that was shaded by immersion in A2 coloring liquid. Aging was done using acetic acid 4% for both groups. Color and translucency were measured using a spectrophotometer before and after artificial aging. Flexural strength was measured using a universal testing machine before and after aging. Data were collected, tabulated, and statistically analyzed. Results: Color change of both pre-shaded and liquid-shaded zirconia were within the clinically acceptable range (1.7±0.3) and (1.9±0.3) respectively and there was no significant difference in translucency between both groups' P value (0.253). Flexural strength increased from (921.9±73.3) before aging to (1025.1±178.5) after aging with pre-shaded zirconia while it decreased from (938.6±32.7) before aging too (899±54.5) after aging with liquid shaded zirconia but this difference was statistically non-significant. Conclusion: The shading technique had no noticeable effect on color, translucency, or flexural strength before or after aging.
International Journal of Health Sciences (IJHS), Mar 22, 2022
The purpose of this study was to assess the effect of Nano-silica Coating on the Color and the Mi... more The purpose of this study was to assess the effect of Nano-silica Coating on the Color and the Microleakage of Zirconia Ceramics. Materials and methods: Eighty-five specimens of commercially available Yttrium-stabilized-zirconia ceramics were constructed and divided into forty-five discs (8 mm in diameter) with thickness (1.2mm) They were divided into three groups (thermocycling-nano-silica surface treatment-and thermocycling with nano-silica surface treatment) to assess the color parameters, while the other forty samples were divided into (control group-thermocyclingnano-silica surface treatment-and thermocycling with nano-silica surface treatment) to perform a fully contoured crowns to assess the microleakage. Initial color measurements were taken using a digital spectrophotometer based on CIE L*a*b* color system using a spectrophotometer Standard permanent molar tooth preparation was conducted into a full veneer preparation. Nano silica sol-gel material painted on the fitting surface of zirconia ceramics in groups of nanosilica and nano-silica with thermocycling surface treatment and processed to firing that were finally cemented on the prepared teeth using resin adhesive luting agent. Samples in aged group were subjected to 5000 thermal cycles then crown samples were sectioned to measure the microleakage. Color measurements of all samples were measured again.
Journal of cardiovascular disease research, 2021
ure mode pattern according to the following categorization. Results: Regarding the fracture resis... more ure mode pattern according to the following categorization. Results: Regarding the fracture resistance testing, the results of the present study revealed that there was no statistically significant difference between mean fracture resistance values of IPS Emax press (235.54 N) and Celtra press; (244.98 N) where both showed statistically non-significant highest mean fracture resistance. Conclusion: The results obtained in this study revealed a non-significant difference between the endocrown restorations and the post and core and crown. Although endocrown showed higher fracture resistance values compared to the post and core and crown. Also the results showed non-significant difference between the endocrown restorations with different designs. Although endocrown (10 mm) showed higher fracture resistance values than endocrown (6 mm) which may be due to an increase in surface area.
Open Journal of Stomatology, 2011
Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay re... more Objectives: A comparison study between ceramic full coverage FPDs & 3 designs of ceramic inlay retained FPDs regarding vertical marginal gap & retention. Materials & Methods: Twenty samples were constructed and divided into 4 groups according to the type of restorations: full coverage, inlay-shaped (occluso-proximal inlay + proximal box), tub-shaped (occluso-proximal inlay), and proximal box-shaped FPDs. All samples were subjected to a vertical marginal gap measurements followed by a retention test. Results: The vertical marginal gap data showed no significant difference between full coverage FPDs, the tub-shaped inlay retained FPDs and the proximal box-shaped inlay retained FPDs. While there was a difference between these three designs and the inlay retained FPDs. Regarding retention, the full coverage FPDs recorded higher retentive strengths and was significant difference than all inlay retained FPDs designs tested. The inlay-shaped design was significant difference than the other two inlay retained FPDs designs. Conclusions: There was no significant difference between full coverage FPDs, tub-shaped & proximal box shaped inlay retained FPDs as regard vertical marginal discrepancies. While, the inlay-haped design showed the highest vertical marginal discrepancies. The premolar & molar retainers for the same type of restorations showed no difference in vertical marginal discrepancies. All measured vertical marginal discrepancies were in the range of clinical acceptance. The full coverage FPDs recorded higher retentive strengths than all inlay retained FPDs designs tested. The inlay-shaped design recorded the highest retentive strengths among the three inlay retained FPDs designs. There was no difference as regard retentive strengths between tub-shaped & proximal box shaped inlay retained FPDs.
Egyptian Dental Journal
Objective The goal of this study was to find out how aging and a surface treatment called solgel ... more Objective The goal of this study was to find out how aging and a surface treatment called solgel nano silica affect microleakage in zirconia ceramic crowns. Materials and methods: Twenty recently extracted human maxillary first molars were prepared for full coverage zirconia crowns made of Yttrium-stabilized zirconia ceramics that are readily available. They were split into four groups, each with five samples the control group, the thermocycling group, the nanosilica group, and the nanosilica-thermocycling group. Zirconia crown fitting surfaces were coated with a sol-gel nano silica substance. Thermal cycling was performed 5000 thermal cycles. TheraCem resin cement was used to cement all of the crowns. Crowns were submerged in 0.5% methylene blue solution for 24 hours before being sectioned bucco-lingually for microleakage testing. The depth of dye penetration was evaluated using a light stereomicroscope (Nikon MA100 Japan) at 50 magnification and image analysis software (Omnimet, Buchler, USA). The Tukey test and one-way ANOVA were used for statistical analysis. Result: The nanosilica group had the lowest microleakage, followed by the nano-silica with thermocycling group. Among the groups, the thermocycling group had the highest microleakage values. Conclusion: Although sol-gel nano silica coating reduces microleakage, ageing has a negative impact on it.
Egyptian Dental Journal
Objective: The aim of this study is to evaluate the effect of ceramic repressing on internal fit ... more Objective: The aim of this study is to evaluate the effect of ceramic repressing on internal fit of two different pressable ceramic materials. Materials and Methods: Two commercially available glass ceramic materials were used in this study; IPS E-max press (Ivoclar, vivadent) and Celtra press (Dentsply, Sirona). The two materials were used to fabricate veneer samples as which a total of twenty veneers were constructed. The samples for each material(n=10) were randomly divided into two equal groups; Group A: Pressed specimens (n=5) veneer shaped wax patterns were invested and heat-pressed according to the manufacturer's recommendations and Group B: Repressed specimens (n=5) the leftover material from 1st pressing was recovered and the buttons were adjusted to fabricate the specimens by repeated heat-pressing using the same procedures as for (A The internal gap distance between the veneers and the resin dies substance ware measured with the stereomicroscope at three preselected locations at 70× magnification. Internal fit adaptation was recorded and mean values for each group determined. Data was statistically analyzed. Results: For IPS E.max or Celtra press; there was no statistically significant difference between mean values of press and repress conditions (P <0.05) between tested groups. It was found that internal gab mean values was recorded for Celtra repress recorded (96.6±6.4) μm which was the highest value which gave poorest fit then E-max repress was recorded (92.6±7.6) μm , Celtra press recorded (91.8±2.8) μm, however E-max press recorded (91.6±5.6) μm which was the lowest mean value for internal fit test. Conclusions: The optimum properties for lithium disilicate Press ceramic materials are obtained with the first pressing. However the microstructure and mechanical characteristics could be impacted by numerous heat repressions, but there would be no statistically significant change in how the internal fit would adjust.
International journal of health sciences, 2022
Objective The purpose of this study was to assess the effect of Nano-silica Coating on the Color ... more Objective The purpose of this study was to assess the effect of Nano-silica Coating on the Color and the Microleakage of Zirconia Ceramics. Materials and methods: Eighty-five specimens of commercially available Yttrium-stabilized-zirconia ceramics were constructed and divided into forty-five discs (8 mm in diameter) with thickness (1.2mm) They were divided into three groups (thermocycling – nano-silica surface treatment – and thermocycling with nano-silica surface treatment) to assess the color parameters, while the other forty samples were divided into ( control group – thermocycling – nano-silica surface treatment – and thermocycling with nano-silica surface treatment) to perform a fully contoured crowns to assess the microleakage. Initial color measurements were taken using a digital spectrophotometer based on CIE L*a*b* color system using a spectrophotometer Standard permanent molar tooth preparation was conducted into a full veneer preparation. Nano silica sol-gel material pain...
INTRODUCTION Endodontically treated teeth restoration is compromised primarily because increased ... more INTRODUCTION Endodontically treated teeth restoration is compromised primarily because increased risk of coronal destruction that results in tooth fracture during function. Before the introduction of adhesion in dentistry, the coronal restoration endodontially treated teeth has been mainly performed with metallic and macro mechanically retained posts. In the past, a length of post equal to three fourths of the root canal or at least equal to the crown length (Goodacre CJ, Spolnik KJ, 1995; Abramovitz L, et al., 2001). A restorative option for endodontically treatment an endocrown is. It consists of a full crown that extends a post into the pulp chamber and/ or pulp canals as one unit (Lander E and Dietschi D, 2008). One of option to restore severe destructed, supragingival structure of posterior teeth (Stockton L, et al., 1998) endocrown. These restorations are the most prevalent in case of damaged molars crowns, narrow and short roots, obturated canals or limited interocclusal spac...
Neuroquantology, May 10, 2022
Objective: The aim of this study is to evaluate the retention of lithium disilicate crowns cement... more Objective: The aim of this study is to evaluate the retention of lithium disilicate crowns cemented by resin cement on zirconia and titanium implant abutments coated with glycerin and eugenol. Materials and Methods: Forty implant analogs were embedded in forty blocks of epoxy resin. Twenty implant analogs received a zirconia implant abutment to which 20 IPS e.max press crowns were cemented. The other twenty implant analogs received a titanium implant abutment to which 20 IPS e.max press crowns were cemented. According to the cementation technique, the samples were subdivided into two groups, 10 samples each. In Gp A, zirconia implant abutments’ surfaces were coated with a single coat of eugenol before cementing crowns with the permanent resin luting cement. In Gp B, same as in Gp B with replacement of eugenol with single coat of glycerin. In Gp C, Titanium implant abutments’ surfaces were coated with a single coat of eugenol before cementing crowns with the permanent resin luting cement. In Gp D, same as in Gp C with replacement of eugenol with single coat of glycerin. Each sample was subjected to a pull-out test. Loads required to remove the crowns were recorded, and mean values for each group determined. Data were statistically analyzed. Results: The mean values ±SD of loads at failure (n -10) for each group were as follows in Newton (N): Group(A) 141.9±17.9, Group(B) 134±14.5, Group(C) 140.5±17, Group(D) 143.6±12.4. All groups showed statistically insignificant difference in retention (p<0.05). Conclusions: There was no significant difference between eugenol and glycerin coated zirconia implant abutments in retention of lithium disilicate crowns. There was no significant difference between eugenol and glycerin coated titanium implant abutments in retention of lithium disilicate crowns.
Open Access Macedonian Journal of Medical Sciences
AIM: The focus of this research was to see how silica nanoparticles changed veneering porcelain o... more AIM: The focus of this research was to see how silica nanoparticles changed veneering porcelain over a zirconia core affected flexure strength, shear bond strength, and color. METHODS: A total number of 30 zirconia core veneer samples were constructed and classified according to silica nanoparticles modification of veneering porcelain into two groups: Group 1 (control group) veneering porcelain without any modification (n = 15) and Group 2 (modified group) veneering porcelain modified by silica nanoparticles (n = 15). Silica nanoparticles were added to the veneering porcelain powder at a rate of 5% by weight. Silica nanoparticles powder and veneering porcelain powder were manually crushed for about 10 min using a pestle and mortar then the mixed powder was combined with the porcelain moldings liquid to make a paste. After thermal cycling, each group was examined for flexural strength, shear bond strength, and color measurement (n = 5). Universal testing equipment was used to determi...
Open Access Macedonian Journal of Medical Sciences
BACKGROUND: The color of all ceramic restorations has a significant effect on the final appearanc... more BACKGROUND: The color of all ceramic restorations has a significant effect on the final appearance of the restoration. AIM: This study aimed to evaluate the effect of different shading techniques on the color stability of monolithic zirconia crowns cemented on the upper anterior teeth. METHODS: In this study, there were nine patients. Each patient has undergone a reduction for the upper six anterior teeth. Fifty-four zirconia jacket crowns were constructed using CAD/CAM technique. According to the shading technique, the crowns were categorized into two groups (pre-shaded and liquid shaded), where the upper right reduced teeth received pre-shaded zirconia crowns while the upper left reduced teeth received liquid-shaded zirconia crowns according to the selected shade. The color was assessed using easy shade after cementation and 1 year follow-up period. Data were collected, tabulated, and statistically analyzed. RESULTS: Color change (ΔE) of the cemented pre-shaded zirconia crowns on ...
Systematic Reviews in Pharmacy, 2021
Objective: The purpose of this in vitro study will evaluate marginal gap of endocrowns retained b... more Objective: The purpose of this in vitro study will evaluate marginal gap of endocrowns retained bridges replacing missing lower second molar will done by two different designs from monolithic zirconia. Material and method: twenty bridges designed from monolithic zirconia. Specimens will be divided into two groups, each of these groups contains 10 samples, the first group represents endocrown endocrown retained, and second group endocrown retained bridges. The marginal gap for the buccal, lingual, proximal and connector area were measured .scan electron microscope were used. Universal testing machine was used to detect fracture resistance for all samples. Results: Data analysis was performed by student t-tests to detect significance between groups. One way analysis of variance ANOVA test followed by pair-wise Newman-Keuls was used to detect significance between sites. Statistical analysis was performed using Graph pad Prism-4 statistics software for Windows. P values 0.05). Conclusio...
Aim: The purpose of this study is to evaluate the effect of surface treatments on color of lithiu... more Aim: The purpose of this study is to evaluate the effect of surface treatments on color of lithium disilicate ceramic (IPS e. max [CAD]) and hybrid ceramic (VITA Suprinity [pc]). Method: Ceramic blocks were sectioned in to one hundred sixty discs; eighty discs of lithium disilicate were randomly subdivided in to four groups according to surface treatment (n= 20). Group C: Control group without surface treatment; group I: using (AL2O3) particles size 50μm; group II: Hydro fluoric (HF) acid etching; group III: tribochemical (TBC) surface treatment. Eighty discs of hybrid ceramic (n= 20) were subdivided in to the same groups. Color measurements were performed with spectrophotometer and repeated after surface treatments. ∆E values were statistically analyzed with oneway ANOVA, Tukey's post hoc test was done to identify significance between groups. Statistically significance was considered when P value ≤ 0.05. Results: Changing color of lithium disilicate specimens were not clinicall...
Objectives: The presence of fine-grained crystals of lithium silicate, which contains a high amou... more Objectives: The presence of fine-grained crystals of lithium silicate, which contains a high amount of glass provides the material it’s optical and mechanical characteristics. This unique microstructure allows this material to be processed in a dental lab quickly and efficiently in its crystalline state and the exact tooth shade. This study aims to evaluate the color stability of zirconia reinforced lithium silicate ceramic and lithium disilicates ceramic restorations. Materials and Methods: In this in vitro study, 40 discs of 2mm thickness and 10mm in diameter would be fabricated, all samples were divided into two groups (n=20) according to ceramic material used: group Z zirconia reinforced lithium silicates ceramic(ZLS) and group L lithium disilicate ceramic(LS) discs. Each group was subdivided into two subgroups according to the aging process (n=10) (before and after aging). CIELAB color parameters of all samples were calculated from spectral reflectance measurements on a spectro...
Systematic Reviews in Pharmacy, 2021
Objective: The purpose of this study was to investigate Effect Of Corrosion On Some Properties Of... more Objective: The purpose of this study was to investigate Effect Of Corrosion On Some Properties Of Dental Ceramics. Materials and Method: Twenty four samples were constructed and divided into 3 groups according to ceramic materials used (8 samples for each) group 1(E max), group 2(High Translucent Zirconia (DD BioZx2)) and group 3 (Opaque Zirconia. (DD BioZ)). Then each group was subdivided into three subgroups (3 samples each) according to sequence of tests performed. Then 4 samples from each subgroup were subjected to acetic acid as a corrosive agent. Those samples were first weighted, after that subjected to corrosion test, then weighted again to determine weight loss of each sample. Then samples were tested for color stability using the VITA Easy shade before and after corrosion. shade guides for samples were used (A3). Disinfection methods included immersion for 10 minutes in 1 of the tested disinfectant solutions (5.25% sodium hypochlorite, 2% alkaline gluteraldehyde or 1.7% tr...
Egyptian Dental Journal, 2021
Objective: investigation of the microshear bond strength between lithium disilicate with preheate... more Objective: investigation of the microshear bond strength between lithium disilicate with preheated viscous composite, flowable composite and resin cement by comparison of their microshear bond strength. Material and method: forty five samples were prepared and divided into three groups; preheated viscous composite group, flowable composite group and resin cement group. Materials were injected into custom made plastic transparent molds (2 mm height, 2 mm diameter) on surface of lithium disilicate discs that were previously surface treated with ceramic etchant (hydrofluoric acid 4.5%) and ceramic primer (silane coupling agent). Then, Microshear bond strength test was performed to samples by universal testing machine. Results were tabulated and statistically analyzed for each group. Results: highest microshear bond strength was recorded for preheated viscous composite followed by flowable composite and resin cement. Conclusions: preheated viscous composite is an excellent material in c...
Objective: the purpose of this study was to investigate fracture strength of two types of hybrid ... more Objective: the purpose of this study was to investigate fracture strength of two types of hybrid ceramic posterior occlusal veneers with different thicknesses. Materials and methods: Eighty natural maxillary molars of comparable size and morphology will be selected. Standardization of the teeth preparations will be accomplished using a diamond saw; teeth will be sectioned horizontally, removing all coronal tooth structure 4 mm occlusal to the CEJs leaving exposed dentin centrally and peripheral enamel. Samples will be randomly divided into two groups (n=40) based on restorative materials that will be used: computer-milled hybrid ceramic (ENAMIC) and Resin Nano Ceramic (LAVA ULTIMATE). Each group will be divided into two subgroups (20 samples each) according to the type of preparation (conventional and experimental). The experimental preparation will have an additional preparation feature. Within each subgroup, specimens were subdivided into two classes (consisting of 10 specimens ea...
Objective: investigation of the microshear bond strength between lithium disilicate with preheate... more Objective: investigation of the microshear bond strength between lithium disilicate with preheated viscous composite, flowable composite and resin cement by comparison of their microshear bond strength. Material and method: forty-five samples were prepared and divided into three groups; preheated viscous composite, flowable composite and resin cement. Materials were injected into plastic transparent molds (2 mm height, 2 mm diameter) on the surface of lithium disilicate discs previously surface treated with ceramic etchant (hydrofluoric acid 4.5%) and ceramic primer (silane coupling agent). Microshear bond strength test was performed samples by universal testing machine. Results: highest microshear bond strength was recorded for preheated viscous composite. Conclusions: preheated viscous composite is an excellent material in cementation of lithium disilicate ceramic restorations.
Objectives: Wear assessment of different ceramic restorations placed against different occlusal a... more Objectives: Wear assessment of different ceramic restorations placed against different occlusal antagonists. Materials and methods: Sixty ceramic sample discs (13mm in diameter and 2mm in thickness) were divided into two groups; full contour zirconia (Zr) and lithium disilicate press on zirconia substrate (E.max) discs. Sixty antagonists were constructed and subdivided into three subgroups: (1)Discs wearing against extracted teeth. (2) Discs wearing against Porcelain fused to metal crowns (PFMc). (3)Discs wearing against full contour zirconia crowns (Zrc).Sample discs and antagonists were dynamically three-body loaded in dual axis chewing simulator with 49 N for 75000 loading cycles. Wear measurement for sample discs and antagonist were calculated using height, weight loss,and surface roughness. Data were statistically analyzed with a 2-way analysis, followed by a Tukey test when showed significantly. Student t-test was done between main groups. Results: E.max showed statistically s...