Nadia Z Fahmy | Modern Science and Arts (MSA) university (original) (raw)

Papers by Nadia Z Fahmy

MSA Dental Journal

Background: The purpose of this study is to evaluate the effect of two glass ceramic materials an... more Background: The purpose of this study is to evaluate the effect of two glass ceramic materials and resin cement curing modes on the color stability of sectional porcelain laminate veneers following artificial aging. Methods: Forty sound human maxillary central incisors were prepared to receive sectional laminate veneers (SLVs) with a thickness of 0.5-0.7 mm. Prepared teeth were randomly divided into 2 equal groups according to ceramic materials used (N=20) as follows: Group I: IPS e.max press. Group II: Celtra press. Each main group was randomly subdivided into 2 equal subgroups according to resin cement used: light and dual cure resin cements (Relyx Veneer) (Relyx Ultimate) respectively. All samples were subjected to 10,000 cycles of thermo-cycling. Color change was measured by laboratory spectrophotometer before and after thermocycling. All the collected data were statistically analyzed by One-way ANOVA followed by Tukey's post hoc test. Results: Color change between restoration and natural side of each sample before and after artificial aging did not reveal significant difference (P<0.05). IPS e.max press showed significant lower color stability with dual and light cure resin cement (ΔE 3.48-ΔE 3.4) than Celtra press (ΔE 2.6-ΔE 3.05). Light cured resin cement used with Celtra press showed statistically significant higher ΔE value than dual cured cement (P>0.05). Conclusions: Celtra press glass ceramic is more color stable than IPS e.max press. Resin cement and aging process influenced the color stability of sectional laminate veneers. Results were clinically accepted for all tested materials in reference to natural teeth (ΔE<3.5). The results may help the patient to aesthetically correct their anterior teeth with a suitable material providing strength and natural teeth looking, in addition to conservation of tooth structure, with optimum esthetics.

MSA Dental Journal

Background: Occlusal veneers fabricated with different materials and thicknesses can reveal diffe... more Background: Occlusal veneers fabricated with different materials and thicknesses can reveal different marginal adaptation after thermodynamic aging. Methodology: Extracted maxillary premolar teeth (n=28) were collected and embedded in epoxy resin block with light body material then randomized according to materials into two groups (n=14): Lithium disilicate IPS e.max CAD (A) and Zirconia reinforced lithium silicate Celtra Duo (B) then further randomized into four subgroups (n=7) according to occlusal veneer thicknesses 1 mm and 1.5 mm. Teeth were prepared by a customized milling machine then the exposed dentine was immediately sealed by dentine bonding agent. Fabrication of the occlusal veneers was done by CAD/CAM milling machine. Occlusal veneers were adhesively cemented by dual cure resin cement (Panavia F 2.0). All samples were subjected to thermocycling and cyclic loading equivalent to one year of service (150,000). Marginal gap measurements then were done with A digital microscope at 35x magnification was used to photograph each specimen. Marginal gap was measured and evaluated using a computerized image analysis system. Results: two-way ANOVA showed that the materials only IPS e.max CAD (39.30±5.14) had significantly higher value than Celtra Duo (31.52 ± 5.69) (p<0.001). While regarding the thicknesses 1 mm thick samples (36.78 ± 6.06) had significantly higher value than 1.5 mm thick samples (34.04 ± 7.02) (p=0.020). Conclusion: Zirconia reinforced lithium silicate (Celtra DUO) occlusal veneers showed better marginal adaptation than lithium disilicate (IPS e.max CAD) in different thicknesses. Zirconia reinforced lithium silicate (Celtra DUO) marginal adaptation was influenced by occlusal veneer thickness (the thicker 1.5 mm showed better adaptation than 1mm.

Journal of Prosthodontics, 2010

Purpose: This study was designed to compare an alternative indirect treatment to repair fractured... more Purpose: This study was designed to compare an alternative indirect treatment to repair fractured or chipped veneering metal ceramic using recently developed ultralow-fusing ceramics. Materials and Methods: One conventional feldspathic ceramic, Vita Omega, and three ultra-low-fusing ceramics (ULFC), Finesse, Duceram LFC, and Vision-low, were used. Forty ceramic specimens were prepared and divided into two groups. Group I (n = 20) was designed for bond strength testing. It comprised four subgroups (A, B, C, D): one Ceramic-resin (A) and three Ceramic-ULFC disc specimens of different diameters (B, C, D). Group II was composed of repaired ceramic discs using direct and indirect repair methods for biaxial testing. It was comprised of five subgroups: the fractured discs from subgroup A; Omega discs (n = 20) formed the repaired specimens of the four remaining subgroups: B, C, D, E. Data were presented as means and standard deviation (SD) values. One-way analysis of variance (ANOVA) was used for comparison between means. Tukey's post hoc test was used for pairwise comparison between the means when ANOVA test was significant. The significance level was set at p ≤ 0.05. Results: Within group I, Omega-Ducera LFC showed the statistically highest mean bond strength (25.8 MPa) values, followed by Omega-Finesse (15.8 MPa). No statistically significant difference was apparent between Omega-Vision (9.3 MPa) and the control Omega-Composite group (7.5 MPa). Regarding group II, the Control Omega subgroup showed statistically the highest mean biaxial strength values (168.8 MPa). No statistically significant difference was evident between the values of Omega-Finesse (78.7 MPa), Omega-Vision (78.4 MPa), and Omega-Composite (82.5 MPa). Omega-Ducera LFC subgroup, showed statistically the lowest mean values (53 MPa). Conclusions: Omega-Ducera LFC yielded the statistically highest mean bond strength values, and the lowest biaxial strength values. All values were within the reported bond strength values for resin repair. All the tested groups showed significantly lower values compared to the initial biaxial strength mean values of the Omega ceramic; however, two of the tested ULFC (Vision, Finesse), recorded means that were statistically equal to the resin-ceramic direct subgroup. Duceram LFC showed the lowest values, probably due to its totally glass composition, which showed low strength values of the repaired specimens. The recorded bond and biaxial values suggest that indirect repair of fractured LFC using some ULFC ceramics may offer an alternative solution to the traditional direct resin repair method; however, the choice of the used ceramic should be one containing some leucite crystals. Further studies are needed to investigate the long-term performance of the proposed repair treatment. Metal ceramic restorations continue to be widely used in dental practices, as they combine esthetics with superior mechanical properties. Although these ceramic materials provide an excellent, durable, and compatible restorative service, failures still occur due to their brittle nature. These have been reported as

Journal of Prosthodontics, 2010

Purpose: This study was undertaken to assess the influence of three-veneering materials on the ma... more Purpose: This study was undertaken to assess the influence of three-veneering materials on the marginal fit, fracture resistance, and failure pattern of In-Ceram alumina crowns. Materials and Methods: Forty In-Ceram cores were constructed and divided into four groups of ten each. Ten alumina cores were left unveneered, forming the first group for core testing, while the other 30 copings were divided into three groups depending on the veneering material used. The vertical marginal gaps of the alumina copings were measured before and after veneer placement at 16 sites using an optical microscope. The specimens were then loaded to fracture at a crosshead speed of 1 mm/min. Fractured specimens were examined, and the fracture patterns of the crowns were recorded. Selected specimens were examined using scanning electron microscope. Data were presented as means and standard deviation values. One-way ANOVA was used to compare between mean gap areas and fracture resistance of the three materials. Duncan's post hoc test was used for pairwise comparison between the means when ANOVA test was significant. Results: Vitadur-N-veneered crowns showed statistically the highest mean vertical gaps, while no significant difference was evident between the marginal fits of Vitadurαand VM7-veneered crowns. Regarding the strength, a statistically significant decrease in fracture resistance of the cores was evident after veneering with Vitadur-N; however, no significant change in mean fracture resistance value of Vitadur-α-and VM7-veneered crowns was evident compared to the alumina cores. VM7-veneered crowns showed the highest fracture resistance values. Conclusions: Vitadur-N-veneered crowns showed the highest mean vertical gaps and the lowest mean fracture resistance values of the tested groups, while VM7-veneered crowns combined the highest fracture resistance values and clinically acceptable margins. The best interface quality and finest ceramic texture were evident in case of VM7 material. An ideal all-ceramic restoration, which combines excellent physical properties, marginal fit, and esthetics, is the goal of the dental profession. Reinforced all-ceramic restorations are mostly composed of layered structures with a high-strength core material, laminated with esthetic but weak veneer porcelains. 1 Glass-infiltrated sintered alumina (In-Ceram, Vita Zahnfabrik, Bad Sackingen, Germany), one of these many systems, is based on the slip casting of an alumina core with its subsequent glass infusion. This core material is veneered with esthetic feldspathic porcelain. The partially sintered porous core is composed of 85% Al 2 O 3 , which is subsequently infiltrated with molten lanthanum glass infiltration in a second-firing process. It reaches a flexural strength of approximately 400 MPa. 2-4

Egyptian Journal of Health Care, 2019

Background: Maternal calcium absorption increases significantly during the second and third trime... more Background: Maternal calcium absorption increases significantly during the second and third trimesters. This increase in calcium absorption is directly related to maternal calcium intake if found defect in calcium level during pregnancy that causes many problem for mother and fetal. This study Aimed to: assess the knowledge, practice and attitude of pregnant women about effect, deficiency of calcium during pregnancy. Subjects and Methods: A descriptive design the study was conducted at both in outpatient clinic for pregnant women, in obstetrics and gynecology department at Benha university hospital. The study included 300 pregnant women by systematic random sample. Tools: (I) An interviewing questionnaire sheet was done constructed by researcher, tool (II) Modified liker scale to assessment the attitude Result: highly statistical significant relation between their total knowledge score and their personal characteristics. No statistical significant relation between their total practice score and their personal characteristics. No statistical significant relation between his total attitude score and their occupational status, educational level and social level. Conclusion low level of knowledge about important of calcium for fetus, Poor practice toward calcium intake and decrease practice for activity daily living, calcium supplementation Recommendations: Health educational, Programs regarding nutritional, in the future calcium supplements should be give free.

Brazilian Dental Science, 2022

Increased patient demands for highly esthetic implant superstructure in the anterior esthetic zon... more Increased patient demands for highly esthetic implant superstructure in the anterior esthetic zone has increased in the last decades. Moreover, the absence of periodontal ligament in implant supported prosthesis causes forces to be transferred without cushioning effect to the alveolar bone, resulting in increased marginal bone loss (MBL) and influence the heath of peri-implant tissue. Evaluate the available evidence on the effect implant superstructure and it consequences on patient satisfaction, MBL, bleeding on probing (BOP) and probing depth (PD). A protocol of electronic and hand research was performed for English based researches comparing implants inserted in the esthetic zone with all ceramic superstructure: "Will the use of different types of all ceramic superstructure show different esthetic patient satisfaction, marginal bone loss, bleeding on probing and probing depth? Thirteen publications from one thousand one hundred and sixteen research studies were included. This systematic review showed that all ceramic implant superstructure was a versatile treatment option with higher esthetic patient satisfaction and better color of peri-implant mucous especially in patients having thin biotype. On the other hand there wasn't significant difference in MBL, PD and BOP compared to other conventional implant superstructure. More randomized controlled clinical trials with bigger samples are needed to confirm our findings. All ceramic implant superstructure is versatile and highly esthetic treatment option for implant placed in the anterior esthetic zone.

The International Journal of Prosthodontics

R apid development in adhesive dentistry has opened a wide range of applications for different ma... more R apid development in adhesive dentistry has opened a wide range of applications for different materials, designs, and treatment plan options. One of these applications is for resin-bonded fixed dental prostheses (RBFDPs). Many reports have been published highlighting the success rates regarding the use of veneers and RBFDPs. 1-6 Restoring a single-tooth anterior edentulous span has been a challenge for many years. Restoration may be necessary due to premature tooth loss from trauma, congenitally missing teeth, or periodontitis. Treatment options available to restore a missing lateral incisor include orthodontic treatment, implant treatment, and prosthetic treatment. 7 Treatment choice should be primarily concerned with conserving tooth structure by using the least invasive approach, bearing in mind careful case selection for longevity of the prosthesis. 8 RBFDPs have been used to restore single teeth anteriorly or posteriorly with strict guidelines for achieving moderate-to long-term serviceability. 9 Moreover, RBFDPs may be applied in young patients, allowing preservation of tooth structure. The use of conventionally (ie, palatally) retained RBFDPs is well documented in the literature, with mid-term and long-term survival rates. 1,3 Recently, with the increased focus on esthetic enhancement and rapid development in bonding, labial veneer-retained fixed dental prostheses have emerged through clinical reports as a possible treatment option. Purpose: To evaluate the effect of three two-retainer designs of a resin-bonded fixed dental prosthesis (RBFDP) on fracture resistance. Materials and Methods: A total of 21 three-unit, all-ceramic RBFPDs were fabricated to replace a missing maxillary lateral incisor. The prostheses were divided into three groups of 7 each: Group L (labial RBFPD); Group ML (modified labial RBFPD, fabricated the same as in Group L with additional preparation that included a shallow proximal groove at the pontic side); and Group P, an all-ceramic palatal RBFPD that acted as control. Preparations were done on the maxillary left central incisor and canine of a typodont model, and 21 epoxy resin models were duplicated for the three groups. The RBFPDs were designed using CAD software and constructed using the heat-pressed technique, after which the prostheses were bonded to their corresponding epoxy resin model according to the manufacturer's instructions. A fracture resistance test was performed on all specimens following aging. Data were analyzed using one-way ANOVA. Results: The highest fracture load values were recorded in Group P (547.5 N), followed by Group ML (462.6 N) and then Group L (418.3 N). The difference among the three designs was not statistically significant (F = 2.5, P = 0.1). Conclusion: Both labial and modified labial RBFDPs could be a viable alternative treatment option for replacement of missing maxillary lateral incisors. Int J Prosthodont 2020 (9 pages).

Dentistry, 2012

Statement of problem: A dowel is essential to retain the core in case of severe tooth destruction... more Statement of problem: A dowel is essential to retain the core in case of severe tooth destruction. However, the placement of a dowel and core may actually weaken teeth and affect their failure pattern depending on their material properties and stress transfer. Purpose: The present study compared the fracture resistance and failure pattern of endodontically treated premolars with different amounts of tooth destruction restored with dowels of different materials: a heat pressable ceramic (IPS e.max) and glass fiber reinforced dowels with 3 dowel space designs. Materials and methods: Ninety single rooted premolars of similar dimensions were selected and divided at random into 9 groups (n=10) Group 1: Sound teeth (Control group), Group 2: Reduced sound teeth with 60 taper and a 1 mm shoulder FL. Groups (3-9) were endodontically treated and divided as follows: Group 3: Restored teeth with minimal endodontic access. Groups 4, 5 and 6 restored using a pressable ceramic dowel and core while groups 7, 8 and 9 were restored using fiber dowels and composite cores. The samples were loaded to fracture and the mode of fracture for each group was examined. The recorded values were tabulated and statistically analyzed. Results: Group 5 (tapered ceramic) showed the highest fracture mean values followed by group 6 (parallel ceramic). Group 4 (parallel tapered ceramic) showed statistically similar values to group 1 (sound teeth).Group 2 (Reduced sound teeth) registered 20% reduction in fracture resistance when compared to group 1 (sound teeth). Group 3 (minimal endodontic access) showed statistically similar values to group 2. Fiber groups 7, 8 and 9 displayed statistically similar mean fracture resistance values, which were 30% lower than those of groups 2 and 3. Conclusions: Reduction of sound teeth resulted in 20% decrease in their fracture resistance. Endodontically treated premolars with minimal access, restored with composite, maintained the same values as sound reduced teeth. Pressed ceramic bonded dowel and cores with three dowel designs displayed higher resistance means than sound reduced teeth; however, most failures were unfavorable. Fiber dowels and composite core groups registered approximately 70% of the values of sound reduced teeth but all failure patterns were favorable.

Journal of Prosthodontics, 2009

Purpose: This study assessed the efficiency of reinforcing provisional restorations by adding a f... more Purpose: This study assessed the efficiency of reinforcing provisional restorations by adding a fine gauze metallic mesh or polyethylene fibers between the abutments spanning the pontic length. Materials and Methods: Forty-five resin fixed partial dentures (FPDs) were constructed using three provisional resins. The three resin groups were further divided into three subgroups depending on their reinforcement. Specimens were loaded compressively, and the load required to fracture the specimens was recorded in Newtons. Data were presented as means and standard deviation values. A regression model with two-way ANOVA was used in testing significance. Duncan's post hoc test was used for pairwise comparison (p ≤ 0.05). Results: Duralay resin and Duralay fiber-reinforced restorations showed the highest fracture-resistance values, followed by Protemp and Snap, which showed statistically similar values. The three mesh-reinforced resin restoration materials showed no statistically significant difference between their fracture resistance values. Reinforcement did not alter the fracture resistance of Duralay and Protemp resin subgroups, but significantly increased that of Snap, equalizing it with the other resins. The three resin materials had similar moduli. Significant alterations occurred after fiber reinforcement. Results showed that fiber-reinforced Duralay resin showed the highest modulus values, while no statistical difference was found between the moduli of fiber-reinforced Protemp and Snap. Regarding the mesh-reinforced groups, Duralay had the highest modulus followed by Protemp and Snap. Reinforcements altered the modulus values of Duralay resin only. Mesh-reinforced Duralay resin showed the highest mean modulus, but no statistically significant difference was apparent between fiber-reinforced and control groups. As for Protemp and Snap resin subgroups, their moduli remained unchanged by reinforcements. Conclusion: Initially, Duralay resin had higher fracture resistance values than Protemp II and Snap. Fiber and mesh reinforcements increased the fracture resistance of Snap. No statistically significant difference was evident among the fracture resistances of the three mesh-reinforced resin FPD restorations. The three resins had similar moduli. Fiber and mesh reinforcement increased the modulus of Duralay resin but did not change that of Protemp and Snap. Fiber and metal mesh reinforcements may alter the fracture strength and modulus of some, but not all, provisional resins. Interim prostheses are those placed between the time of tooth preparation and placement of the definitive prosthesis. To be successful, they must fulfill biologic, mechanical, and esthetic requirements. 1 These restorations should provide pulpal protection, comfort, positional stability, occlusal function, access for cleaning, esthetics, strength, and retention. 2,3 During the interval of their insertion, the fate of periodontally involved teeth is assessed. 4,5 Prognosis of questionable teeth is evaluated, and therapeutic occlusal vertical dimension is determined. 3,6-8 They also promote guided tissue healing by providing a matrix for surrounding gingival tissues. 4,6,7 Interim fixed partial dentures (FPDs) must preserve abutment position and maintain inter-and intra-arch relationships through the establishment of proximal and occlusal contacts. These requirements

Journal of Prosthodontics, 2009

Purpose: This study aimed to compare the effect of three curing modes of a highpowered curing-lig... more Purpose: This study aimed to compare the effect of three curing modes of a highpowered curing-light source on the shear bond strength and marginal gap of light-and dual-cured adhesive resin cements to dentin. Materials and Methods: Twelve freshly extracted intact human mandibular molars were selected for this study and stored in the saline solution. Three of the axial surfaces of the teeth were prepared to obtain flat dentinal surfaces. Thirty-six ceramic disks (4-mm diameter, 2-mm thick) were constructed from a pressable glass-ceramic (Vision). The discs were etched with hydrofluoric acid and primed, and then divided into two equal groups, groups I and II (n = 18 each). Two adhesive systems were used following manufacturer's instructions. The discs of group I were bonded to the conditioned dentin surface using adhesive resin (Rely X Veneer), and group II discs were bonded to dentin using Rely X ARC. For each group, the resin was cured using three modes (fast, ramp, pulse). Interfacial gap at the dentin/resin interface was measured at eight predetermined sites for each specimen using a stereomicroscope, and shear bond strength of the bonded specimens was carried out using a universal testing machine. Results: Ramp-cured specimens recorded significantly higher mean shear bond strengths for both dual-and light-polymerized resins than those with fast and pulse modes. Moreover, fewer interfacial gaps were found at the resin/dentin interface in association with ramp cure modes of both resins. Most failures were adhesive failures at the dentin-resin luting agent (RLA) interface in specimens polymerized using highpowered LED fast or pulse modes, while a cohesive failure pattern within the resin was associated with the ramp-curing mode. Conclusion: Within the limitations of this study, the shear bond strength of an RLA to dentin was found to be enhanced with light-or dual-polymerized adhesive resin using an LED light in ramp mode, whereas shear bond strength was significantly lower when polymerized using LED in fast or pulse modes.

Journal of Prosthodontics, 2009

Purpose: This study evaluated the effect of artificial saliva storage on the hardness, crack leng... more Purpose: This study evaluated the effect of artificial saliva storage on the hardness, crack length, and fracture toughness of a glazed, polished, and bleached hydrothermal low-fusing glass-ceramic (Duceram LFC). Materials and Methods: Forty ceramic discs were constructed. The discs were assigned to four groups (n = 10) according to their surface finish: Gp1-Autoglaze, Gp2-Autoglaze/ground/diamond-polished, Gp3-Overglaze, Gp4-Overglaze/ground/diamond-polished. Each group was further divided into two subgroups forming eight total subgroups (n = 5). Subgroup A was unbleached; Subgroup B was bleached. Testing was performed before and after 21 days of artificial saliva storage. Data were presented as means and standard deviation (SD). ANOVA was used, along with Duncan's post hoc test for pairwise comparison between the means when ANOVA test was found significant (p ≤ 0.05). Results: Surface treatments such as glazing, polishing, and bleaching, saliva storage, and the interaction between these variables had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness of the specimens. There was a statistically significant increase in microhardness and fracture toughness mean values, while crack length values decreased after saliva storage. Polished specimens recorded the smallest crack lengths and fracture toughness, and highest hardness values before and after saliva storage. No difference in fracture toughness values was evident between glazed and polished specimens. Mean crack lengths decreased after saliva storage in all the tested specimens. Hardness values increased after saliva storage. The autoglazed group showed significantly higher fracture toughness, lower crack length, and microhardness than the overglazed group. Conclusions: Surface finishing procedures and artificial saliva storage had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness. This in vitro study suggests that fracture toughness of ceramics may be affected by different surface treatments such as glazing, polishing, bleaching, or a combination; however, in this study Duceram LFC proved its self-healing property after 3-week storage in artificial saliva.

Journal of Prosthodontics, 2009

Purpose: This study examined the effect of a manufacturer's proposed bleaching protocol on surfac... more Purpose: This study examined the effect of a manufacturer's proposed bleaching protocol on surface properties of a low-fusing ceramic. Materials and Methods: Forty ultra low-fusing ceramic samples (Ducera LFC) were constructed for this study. Half the discs were autoglazed, and the other half were overglazed. The two main groups (autoglaze, overglaze) were further divided into subgroups of four. Group I: autoglazed (control group I), bleached autoglaze, diamond polished, diamond polished and bleached. The same division was applied to Group II: overglazed (control group II), bleached overglazed, diamond polished, diamond polished and bleached. The total number of subgroups was eight. Control groups I and II (n = 10) were both immersed in distilled water, which was changed daily for 1 week. The other six subgroups (n = 30) were subjected to the following protocol: 2-hour bleaching using carbamide peroxide 35%, followed by six 8-hour bleaching applications using 15% carbamide peroxide gel. Every two bleaching procedures were interrupted by a 10-hour fluoride gel application. At the end of each bleaching step, the treated specimens were washed under running water in readiness for the next application. Results: Bleaching did not significantly affect the surface roughness of the autoglazed group; however, it significantly increased the roughness of the overglazed ceramic, especially after polishing. Regarding whiteness, the overglazed group had significantly increased values compared to the autoglazed group. It appeared that bleaching whitened the overglazed specimens significantly, whereas polishing alone showed less whiteness. There appeared to be a strong inverse relation between the roughness and the whiteness of the autoglazed specimens as affected by the bleaching. On the other hand, a weak inverse relation was found between the roughness and whiteness of the overglazed specimens, as affected by the bleaching. Conclusions: In-office bleaching with 35% carbamide peroxide, followed by home bleaching with 15% carbamide peroxide and a fluoride gel may affect the roughness and whiteness of overglazed and polished/overglazed Duceram LFC restorations. No significant change in roughness or whiteness was detected by this bleaching system on autoglazed Ducera LFC. Ceramic restorations should be protected before any bleaching for fear of altering their roughness and whiteness. Patients should be advised that their existing porcelain restorations may not match their natural teeth after bleaching.

Journal of Prosthodontics, 2011

Purpose: This article reviews a press-on metal (POM) ceramic versus a conventional veneering syst... more Purpose: This article reviews a press-on metal (POM) ceramic versus a conventional veneering system regarding marginal gaps, fracture resistance, microhardness, and surface roughness. This was done to provide clinical recommendations for its use. Materials and Methods: Forty crowns were constructed and divided into two main groups according to the metal coping design. Group 1: Twenty metal copings with metal margin extending to the axiogingival line angle. Group 2: Twenty metal copings with metal margin 1 mm occlusal to the axiogingival line angle. The specimens of each group were further subdivided into two subgroups (A and B) according to the veneering porcelain used. The vertical marginal gaps of the crowns were measured after veneering placement. For fracture resistance testing, the crowns were subjected to compressive load to failure. Representative samples of the two main groups were selected to measure surface roughness and microhardness. Results: No statistically significant difference was evident regarding the vertical marginal gap distance in relation to the margin design of both tested groups (p = 0.249, p = 0.815); however, the POM veneer group with metal porcelain margin showed statistically lower marginal gaps than the conventional ceramic veneer group (p = 0.043). Fracture resistance values did not show statistically significant difference regarding the margin design (p = 0.858, p = 0.659) or type of the ceramic veneer material (p = 0.592, p = 0.165). Both groups showed no significant difference in their mean roughness values (p = 0.235). Conventional ceramics showed statistically significantly higher mean microhardness values than POM did (p = 0.008). Conclusion: This study showed superior marginal adaptation, decreased microhardness, and similar load to failure and roughness values of the POM ceramic system. Moreover, considerable ease and speed of fabrication of this system were evident. The high variation in range values of some tested groups is among the limitations of this study, along with the lack of clinical trials to test the system in vivo.

Journal of Prosthodontics, 2010

Purpose: This study was designed to evaluate three veneering materials for an allceramic alumina ... more Purpose: This study was designed to evaluate three veneering materials for an allceramic alumina system in terms of bond strength, microhardness, and core/veneer interface quality. Materials and Methods: Fifteen In-Ceram cores were constructed for this study, forming three groups of five specimens each divided by the veneering ceramic disc fired on the occlusal surface of the alumina core: Vitadur N, Vitadur Alpha, or VM7. The specimens underwent shear bond and microhardness testing. Gross examination of debonded discs by SEM and EDAX analysis was conducted. Data for shear bond strength (SBS) and microhardness were presented as means and standard deviation (SD) values. One-way ANOVA and Duncan's post hoc test were used for pairwise comparison between the means when ANOVA test was significant. Results: VM7 showed the highest shear bond value and lowest microhardness values of the three tested veneering materials. No statistically significant difference was evident between the SBSs of Vitadur N and Vitadur Alpha to the alumina cores. Vitadur Alpha showed statistically the highest mean VHN, followed by Vitadur N, while VM7 showed statistically the lowest mean values of VHN. Conclusions: In-Ceram core/Vitadur N disc debondings appeared to be interfacial by complete delaminations, leaving a shiny visible and quite distinct area, whereas there appeared to be perfect adhesion between the core and VM7 veneering material. VM7 appeared to possess ultra-fine texture with intimate contact to the core, forming what seemed like a transition zone where the ceramic and core appeared to blend for a distance. VM7's finer particle size has improved the core/veneer bond strength and decreased micohardness values. This new veneering material will probably enhance the performance and esthetics of the In-Ceram system.

The Journal of Prosthetic Dentistry, 2008

Statement of problem. Bonding ceramic restorations to tooth structure relies on treatment of the ... more Statement of problem. Bonding ceramic restorations to tooth structure relies on treatment of the ceramic intaglio surface, selection of a suitable resin luting agent, and appropriate treatment of prepared tooth structure. Various ceramic surface treatments have been advocated which produce different topographies and bond strengths, but little information is available to identify the interaction between the resulting surface topography and bond strength. Purpose. The purpose of this in vitro study was to evaluate the effect of surface treatments on surface roughness and bond strength to dentin and enamel of a commercially available heat-pressed dental ceramic (IPS Empress). Material and methods. One hundred heat-pressed ceramic disks were fabricated according to the manufacturer's recommendations. Specimens were divided into 5 groups (n=20) and treated with 1 of the following: (1) etching with 9.5% hydrofluoric acid, (2) 50%, or (3) 60% orthophosphoric acid and airborne-particle abrasion with (4) 50-µm, or (5) 250-µm alumina for 10 seconds. Morphological changes obtained with the surface treatments were investigated with a surface texture analyzer on half of the treated specimens. Two additional specimens from each group were treated and prepared for scanning electron microscopy. The specimens were then used for a bond strength test. The treated specimens were silanated and luted with a composite resin luting agent (Nexus 2) to enamel (n=50) and dentin (n=50) surfaces with 10 specimens for each treatment group. The luted specimens were loaded to failure in a universal testing machine in the shear mode with a crosshead speed of 0.05 mm/min. The data were analyzed with 1-way ANOVA followed by the Ryan-Einot-Gabriel-Welsch Multiple Range Test (α=.05). Results. Surface treatments resulted in significant differences for surface topography and shear bond strength (P<.001). Mean surface roughness (Ra) (SD) was (2.54 (0.21) µm) for ceramic surfaces treated with 50-µm aluminum powder. Treatment of ceramic specimens with 50% orthophosphoric acid appeared to result in a smoother surface (1.02 (0.38) µm). The highest mean bond strength (SD) to enamel (14.7 (0.6) MPa) and dentin (8.2 (1.5) MPa) was associated with hydrofluoric acid etching. The lowest mean bond strength (SD) to enamel (2.7 (0.8) MPa) and dentin (1.5 (0.1) MPa) was recorded for 50% phosphoric acid. Conclusions. Hydrofluoric acid treatment resulted in the generation of pores and grooves that produced the greatest bond strength between the ceramic and tooth dentin and enamel. Orthophosphoric acid treatment was the least effective surface treatment method evaluated. The results are applicable to only the all-ceramic/luting system evaluated.

Journal of Prosthodontics, 2010

Purpose: This study was undertaken to assess the influence of three-veneering materials on the ma... more Purpose: This study was undertaken to assess the influence of three-veneering materials on the marginal fit, fracture resistance, and failure pattern of In-Ceram alumina crowns. Materials and Methods: Forty In-Ceram cores were constructed and divided into four groups of ten each. Ten alumina cores were left unveneered, forming the first group for core testing, while the other 30 copings were divided into three groups depending on the veneering material used. The vertical marginal gaps of the alumina copings were measured before and after veneer placement at 16 sites using an optical microscope. The specimens were then loaded to fracture at a crosshead speed of 1 mm/min. Fractured specimens were examined, and the fracture patterns of the crowns were recorded. Selected specimens were examined using scanning electron microscope. Data were presented as means and standard deviation values. One-way ANOVA was used to compare between mean gap areas and fracture resistance of the three materials. Duncan's post hoc test was used for pairwise comparison between the means when ANOVA test was significant. Results: Vitadur-N-veneered crowns showed statistically the highest mean vertical gaps, while no significant difference was evident between the marginal fits of Vitadurαand VM7-veneered crowns. Regarding the strength, a statistically significant decrease in fracture resistance of the cores was evident after veneering with Vitadur-N; however, no significant change in mean fracture resistance value of Vitadur-α-and VM7-veneered crowns was evident compared to the alumina cores. VM7-veneered crowns showed the highest fracture resistance values. Conclusions: Vitadur-N-veneered crowns showed the highest mean vertical gaps and the lowest mean fracture resistance values of the tested groups, while VM7-veneered crowns combined the highest fracture resistance values and clinically acceptable margins. The best interface quality and finest ceramic texture were evident in case of VM7 material. An ideal all-ceramic restoration, which combines excellent physical properties, marginal fit, and esthetics, is the goal of the dental profession. Reinforced all-ceramic restorations are mostly composed of layered structures with a high-strength core material, laminated with esthetic but weak veneer porcelains. 1 Glass-infiltrated sintered alumina (In-Ceram, Vita Zahnfabrik, Bad Sackingen, Germany), one of these many systems, is based on the slip casting of an alumina core with its subsequent glass infusion. This core material is veneered with esthetic feldspathic porcelain. The partially sintered porous core is composed of 85% Al 2 O 3 , which is subsequently infiltrated with molten lanthanum glass infiltration in a second-firing process. It reaches a flexural strength of approximately 400 MPa. 2-4

MSA Dental Journal

Background: The purpose of this study is to evaluate the effect of two glass ceramic materials an... more Background: The purpose of this study is to evaluate the effect of two glass ceramic materials and resin cement curing modes on the color stability of sectional porcelain laminate veneers following artificial aging. Methods: Forty sound human maxillary central incisors were prepared to receive sectional laminate veneers (SLVs) with a thickness of 0.5-0.7 mm. Prepared teeth were randomly divided into 2 equal groups according to ceramic materials used (N=20) as follows: Group I: IPS e.max press. Group II: Celtra press. Each main group was randomly subdivided into 2 equal subgroups according to resin cement used: light and dual cure resin cements (Relyx Veneer) (Relyx Ultimate) respectively. All samples were subjected to 10,000 cycles of thermo-cycling. Color change was measured by laboratory spectrophotometer before and after thermocycling. All the collected data were statistically analyzed by One-way ANOVA followed by Tukey's post hoc test. Results: Color change between restoration and natural side of each sample before and after artificial aging did not reveal significant difference (P<0.05). IPS e.max press showed significant lower color stability with dual and light cure resin cement (ΔE 3.48-ΔE 3.4) than Celtra press (ΔE 2.6-ΔE 3.05). Light cured resin cement used with Celtra press showed statistically significant higher ΔE value than dual cured cement (P>0.05). Conclusions: Celtra press glass ceramic is more color stable than IPS e.max press. Resin cement and aging process influenced the color stability of sectional laminate veneers. Results were clinically accepted for all tested materials in reference to natural teeth (ΔE<3.5). The results may help the patient to aesthetically correct their anterior teeth with a suitable material providing strength and natural teeth looking, in addition to conservation of tooth structure, with optimum esthetics.

MSA Dental Journal

Background: Occlusal veneers fabricated with different materials and thicknesses can reveal diffe... more Background: Occlusal veneers fabricated with different materials and thicknesses can reveal different marginal adaptation after thermodynamic aging. Methodology: Extracted maxillary premolar teeth (n=28) were collected and embedded in epoxy resin block with light body material then randomized according to materials into two groups (n=14): Lithium disilicate IPS e.max CAD (A) and Zirconia reinforced lithium silicate Celtra Duo (B) then further randomized into four subgroups (n=7) according to occlusal veneer thicknesses 1 mm and 1.5 mm. Teeth were prepared by a customized milling machine then the exposed dentine was immediately sealed by dentine bonding agent. Fabrication of the occlusal veneers was done by CAD/CAM milling machine. Occlusal veneers were adhesively cemented by dual cure resin cement (Panavia F 2.0). All samples were subjected to thermocycling and cyclic loading equivalent to one year of service (150,000). Marginal gap measurements then were done with A digital microscope at 35x magnification was used to photograph each specimen. Marginal gap was measured and evaluated using a computerized image analysis system. Results: two-way ANOVA showed that the materials only IPS e.max CAD (39.30±5.14) had significantly higher value than Celtra Duo (31.52 ± 5.69) (p<0.001). While regarding the thicknesses 1 mm thick samples (36.78 ± 6.06) had significantly higher value than 1.5 mm thick samples (34.04 ± 7.02) (p=0.020). Conclusion: Zirconia reinforced lithium silicate (Celtra DUO) occlusal veneers showed better marginal adaptation than lithium disilicate (IPS e.max CAD) in different thicknesses. Zirconia reinforced lithium silicate (Celtra DUO) marginal adaptation was influenced by occlusal veneer thickness (the thicker 1.5 mm showed better adaptation than 1mm.

Journal of Prosthodontics, 2010

Purpose: This study was designed to compare an alternative indirect treatment to repair fractured... more Purpose: This study was designed to compare an alternative indirect treatment to repair fractured or chipped veneering metal ceramic using recently developed ultralow-fusing ceramics. Materials and Methods: One conventional feldspathic ceramic, Vita Omega, and three ultra-low-fusing ceramics (ULFC), Finesse, Duceram LFC, and Vision-low, were used. Forty ceramic specimens were prepared and divided into two groups. Group I (n = 20) was designed for bond strength testing. It comprised four subgroups (A, B, C, D): one Ceramic-resin (A) and three Ceramic-ULFC disc specimens of different diameters (B, C, D). Group II was composed of repaired ceramic discs using direct and indirect repair methods for biaxial testing. It was comprised of five subgroups: the fractured discs from subgroup A; Omega discs (n = 20) formed the repaired specimens of the four remaining subgroups: B, C, D, E. Data were presented as means and standard deviation (SD) values. One-way analysis of variance (ANOVA) was used for comparison between means. Tukey's post hoc test was used for pairwise comparison between the means when ANOVA test was significant. The significance level was set at p ≤ 0.05. Results: Within group I, Omega-Ducera LFC showed the statistically highest mean bond strength (25.8 MPa) values, followed by Omega-Finesse (15.8 MPa). No statistically significant difference was apparent between Omega-Vision (9.3 MPa) and the control Omega-Composite group (7.5 MPa). Regarding group II, the Control Omega subgroup showed statistically the highest mean biaxial strength values (168.8 MPa). No statistically significant difference was evident between the values of Omega-Finesse (78.7 MPa), Omega-Vision (78.4 MPa), and Omega-Composite (82.5 MPa). Omega-Ducera LFC subgroup, showed statistically the lowest mean values (53 MPa). Conclusions: Omega-Ducera LFC yielded the statistically highest mean bond strength values, and the lowest biaxial strength values. All values were within the reported bond strength values for resin repair. All the tested groups showed significantly lower values compared to the initial biaxial strength mean values of the Omega ceramic; however, two of the tested ULFC (Vision, Finesse), recorded means that were statistically equal to the resin-ceramic direct subgroup. Duceram LFC showed the lowest values, probably due to its totally glass composition, which showed low strength values of the repaired specimens. The recorded bond and biaxial values suggest that indirect repair of fractured LFC using some ULFC ceramics may offer an alternative solution to the traditional direct resin repair method; however, the choice of the used ceramic should be one containing some leucite crystals. Further studies are needed to investigate the long-term performance of the proposed repair treatment. Metal ceramic restorations continue to be widely used in dental practices, as they combine esthetics with superior mechanical properties. Although these ceramic materials provide an excellent, durable, and compatible restorative service, failures still occur due to their brittle nature. These have been reported as

Journal of Prosthodontics, 2010

Purpose: This study was undertaken to assess the influence of three-veneering materials on the ma... more Purpose: This study was undertaken to assess the influence of three-veneering materials on the marginal fit, fracture resistance, and failure pattern of In-Ceram alumina crowns. Materials and Methods: Forty In-Ceram cores were constructed and divided into four groups of ten each. Ten alumina cores were left unveneered, forming the first group for core testing, while the other 30 copings were divided into three groups depending on the veneering material used. The vertical marginal gaps of the alumina copings were measured before and after veneer placement at 16 sites using an optical microscope. The specimens were then loaded to fracture at a crosshead speed of 1 mm/min. Fractured specimens were examined, and the fracture patterns of the crowns were recorded. Selected specimens were examined using scanning electron microscope. Data were presented as means and standard deviation values. One-way ANOVA was used to compare between mean gap areas and fracture resistance of the three materials. Duncan's post hoc test was used for pairwise comparison between the means when ANOVA test was significant. Results: Vitadur-N-veneered crowns showed statistically the highest mean vertical gaps, while no significant difference was evident between the marginal fits of Vitadurαand VM7-veneered crowns. Regarding the strength, a statistically significant decrease in fracture resistance of the cores was evident after veneering with Vitadur-N; however, no significant change in mean fracture resistance value of Vitadur-α-and VM7-veneered crowns was evident compared to the alumina cores. VM7-veneered crowns showed the highest fracture resistance values. Conclusions: Vitadur-N-veneered crowns showed the highest mean vertical gaps and the lowest mean fracture resistance values of the tested groups, while VM7-veneered crowns combined the highest fracture resistance values and clinically acceptable margins. The best interface quality and finest ceramic texture were evident in case of VM7 material. An ideal all-ceramic restoration, which combines excellent physical properties, marginal fit, and esthetics, is the goal of the dental profession. Reinforced all-ceramic restorations are mostly composed of layered structures with a high-strength core material, laminated with esthetic but weak veneer porcelains. 1 Glass-infiltrated sintered alumina (In-Ceram, Vita Zahnfabrik, Bad Sackingen, Germany), one of these many systems, is based on the slip casting of an alumina core with its subsequent glass infusion. This core material is veneered with esthetic feldspathic porcelain. The partially sintered porous core is composed of 85% Al 2 O 3 , which is subsequently infiltrated with molten lanthanum glass infiltration in a second-firing process. It reaches a flexural strength of approximately 400 MPa. 2-4

Egyptian Journal of Health Care, 2019

Background: Maternal calcium absorption increases significantly during the second and third trime... more Background: Maternal calcium absorption increases significantly during the second and third trimesters. This increase in calcium absorption is directly related to maternal calcium intake if found defect in calcium level during pregnancy that causes many problem for mother and fetal. This study Aimed to: assess the knowledge, practice and attitude of pregnant women about effect, deficiency of calcium during pregnancy. Subjects and Methods: A descriptive design the study was conducted at both in outpatient clinic for pregnant women, in obstetrics and gynecology department at Benha university hospital. The study included 300 pregnant women by systematic random sample. Tools: (I) An interviewing questionnaire sheet was done constructed by researcher, tool (II) Modified liker scale to assessment the attitude Result: highly statistical significant relation between their total knowledge score and their personal characteristics. No statistical significant relation between their total practice score and their personal characteristics. No statistical significant relation between his total attitude score and their occupational status, educational level and social level. Conclusion low level of knowledge about important of calcium for fetus, Poor practice toward calcium intake and decrease practice for activity daily living, calcium supplementation Recommendations: Health educational, Programs regarding nutritional, in the future calcium supplements should be give free.

Brazilian Dental Science, 2022

Increased patient demands for highly esthetic implant superstructure in the anterior esthetic zon... more Increased patient demands for highly esthetic implant superstructure in the anterior esthetic zone has increased in the last decades. Moreover, the absence of periodontal ligament in implant supported prosthesis causes forces to be transferred without cushioning effect to the alveolar bone, resulting in increased marginal bone loss (MBL) and influence the heath of peri-implant tissue. Evaluate the available evidence on the effect implant superstructure and it consequences on patient satisfaction, MBL, bleeding on probing (BOP) and probing depth (PD). A protocol of electronic and hand research was performed for English based researches comparing implants inserted in the esthetic zone with all ceramic superstructure: "Will the use of different types of all ceramic superstructure show different esthetic patient satisfaction, marginal bone loss, bleeding on probing and probing depth? Thirteen publications from one thousand one hundred and sixteen research studies were included. This systematic review showed that all ceramic implant superstructure was a versatile treatment option with higher esthetic patient satisfaction and better color of peri-implant mucous especially in patients having thin biotype. On the other hand there wasn't significant difference in MBL, PD and BOP compared to other conventional implant superstructure. More randomized controlled clinical trials with bigger samples are needed to confirm our findings. All ceramic implant superstructure is versatile and highly esthetic treatment option for implant placed in the anterior esthetic zone.

The International Journal of Prosthodontics

R apid development in adhesive dentistry has opened a wide range of applications for different ma... more R apid development in adhesive dentistry has opened a wide range of applications for different materials, designs, and treatment plan options. One of these applications is for resin-bonded fixed dental prostheses (RBFDPs). Many reports have been published highlighting the success rates regarding the use of veneers and RBFDPs. 1-6 Restoring a single-tooth anterior edentulous span has been a challenge for many years. Restoration may be necessary due to premature tooth loss from trauma, congenitally missing teeth, or periodontitis. Treatment options available to restore a missing lateral incisor include orthodontic treatment, implant treatment, and prosthetic treatment. 7 Treatment choice should be primarily concerned with conserving tooth structure by using the least invasive approach, bearing in mind careful case selection for longevity of the prosthesis. 8 RBFDPs have been used to restore single teeth anteriorly or posteriorly with strict guidelines for achieving moderate-to long-term serviceability. 9 Moreover, RBFDPs may be applied in young patients, allowing preservation of tooth structure. The use of conventionally (ie, palatally) retained RBFDPs is well documented in the literature, with mid-term and long-term survival rates. 1,3 Recently, with the increased focus on esthetic enhancement and rapid development in bonding, labial veneer-retained fixed dental prostheses have emerged through clinical reports as a possible treatment option. Purpose: To evaluate the effect of three two-retainer designs of a resin-bonded fixed dental prosthesis (RBFDP) on fracture resistance. Materials and Methods: A total of 21 three-unit, all-ceramic RBFPDs were fabricated to replace a missing maxillary lateral incisor. The prostheses were divided into three groups of 7 each: Group L (labial RBFPD); Group ML (modified labial RBFPD, fabricated the same as in Group L with additional preparation that included a shallow proximal groove at the pontic side); and Group P, an all-ceramic palatal RBFPD that acted as control. Preparations were done on the maxillary left central incisor and canine of a typodont model, and 21 epoxy resin models were duplicated for the three groups. The RBFPDs were designed using CAD software and constructed using the heat-pressed technique, after which the prostheses were bonded to their corresponding epoxy resin model according to the manufacturer's instructions. A fracture resistance test was performed on all specimens following aging. Data were analyzed using one-way ANOVA. Results: The highest fracture load values were recorded in Group P (547.5 N), followed by Group ML (462.6 N) and then Group L (418.3 N). The difference among the three designs was not statistically significant (F = 2.5, P = 0.1). Conclusion: Both labial and modified labial RBFDPs could be a viable alternative treatment option for replacement of missing maxillary lateral incisors. Int J Prosthodont 2020 (9 pages).

Dentistry, 2012

Statement of problem: A dowel is essential to retain the core in case of severe tooth destruction... more Statement of problem: A dowel is essential to retain the core in case of severe tooth destruction. However, the placement of a dowel and core may actually weaken teeth and affect their failure pattern depending on their material properties and stress transfer. Purpose: The present study compared the fracture resistance and failure pattern of endodontically treated premolars with different amounts of tooth destruction restored with dowels of different materials: a heat pressable ceramic (IPS e.max) and glass fiber reinforced dowels with 3 dowel space designs. Materials and methods: Ninety single rooted premolars of similar dimensions were selected and divided at random into 9 groups (n=10) Group 1: Sound teeth (Control group), Group 2: Reduced sound teeth with 60 taper and a 1 mm shoulder FL. Groups (3-9) were endodontically treated and divided as follows: Group 3: Restored teeth with minimal endodontic access. Groups 4, 5 and 6 restored using a pressable ceramic dowel and core while groups 7, 8 and 9 were restored using fiber dowels and composite cores. The samples were loaded to fracture and the mode of fracture for each group was examined. The recorded values were tabulated and statistically analyzed. Results: Group 5 (tapered ceramic) showed the highest fracture mean values followed by group 6 (parallel ceramic). Group 4 (parallel tapered ceramic) showed statistically similar values to group 1 (sound teeth).Group 2 (Reduced sound teeth) registered 20% reduction in fracture resistance when compared to group 1 (sound teeth). Group 3 (minimal endodontic access) showed statistically similar values to group 2. Fiber groups 7, 8 and 9 displayed statistically similar mean fracture resistance values, which were 30% lower than those of groups 2 and 3. Conclusions: Reduction of sound teeth resulted in 20% decrease in their fracture resistance. Endodontically treated premolars with minimal access, restored with composite, maintained the same values as sound reduced teeth. Pressed ceramic bonded dowel and cores with three dowel designs displayed higher resistance means than sound reduced teeth; however, most failures were unfavorable. Fiber dowels and composite core groups registered approximately 70% of the values of sound reduced teeth but all failure patterns were favorable.

Journal of Prosthodontics, 2009

Purpose: This study assessed the efficiency of reinforcing provisional restorations by adding a f... more Purpose: This study assessed the efficiency of reinforcing provisional restorations by adding a fine gauze metallic mesh or polyethylene fibers between the abutments spanning the pontic length. Materials and Methods: Forty-five resin fixed partial dentures (FPDs) were constructed using three provisional resins. The three resin groups were further divided into three subgroups depending on their reinforcement. Specimens were loaded compressively, and the load required to fracture the specimens was recorded in Newtons. Data were presented as means and standard deviation values. A regression model with two-way ANOVA was used in testing significance. Duncan's post hoc test was used for pairwise comparison (p ≤ 0.05). Results: Duralay resin and Duralay fiber-reinforced restorations showed the highest fracture-resistance values, followed by Protemp and Snap, which showed statistically similar values. The three mesh-reinforced resin restoration materials showed no statistically significant difference between their fracture resistance values. Reinforcement did not alter the fracture resistance of Duralay and Protemp resin subgroups, but significantly increased that of Snap, equalizing it with the other resins. The three resin materials had similar moduli. Significant alterations occurred after fiber reinforcement. Results showed that fiber-reinforced Duralay resin showed the highest modulus values, while no statistical difference was found between the moduli of fiber-reinforced Protemp and Snap. Regarding the mesh-reinforced groups, Duralay had the highest modulus followed by Protemp and Snap. Reinforcements altered the modulus values of Duralay resin only. Mesh-reinforced Duralay resin showed the highest mean modulus, but no statistically significant difference was apparent between fiber-reinforced and control groups. As for Protemp and Snap resin subgroups, their moduli remained unchanged by reinforcements. Conclusion: Initially, Duralay resin had higher fracture resistance values than Protemp II and Snap. Fiber and mesh reinforcements increased the fracture resistance of Snap. No statistically significant difference was evident among the fracture resistances of the three mesh-reinforced resin FPD restorations. The three resins had similar moduli. Fiber and mesh reinforcement increased the modulus of Duralay resin but did not change that of Protemp and Snap. Fiber and metal mesh reinforcements may alter the fracture strength and modulus of some, but not all, provisional resins. Interim prostheses are those placed between the time of tooth preparation and placement of the definitive prosthesis. To be successful, they must fulfill biologic, mechanical, and esthetic requirements. 1 These restorations should provide pulpal protection, comfort, positional stability, occlusal function, access for cleaning, esthetics, strength, and retention. 2,3 During the interval of their insertion, the fate of periodontally involved teeth is assessed. 4,5 Prognosis of questionable teeth is evaluated, and therapeutic occlusal vertical dimension is determined. 3,6-8 They also promote guided tissue healing by providing a matrix for surrounding gingival tissues. 4,6,7 Interim fixed partial dentures (FPDs) must preserve abutment position and maintain inter-and intra-arch relationships through the establishment of proximal and occlusal contacts. These requirements

Journal of Prosthodontics, 2009

Purpose: This study aimed to compare the effect of three curing modes of a highpowered curing-lig... more Purpose: This study aimed to compare the effect of three curing modes of a highpowered curing-light source on the shear bond strength and marginal gap of light-and dual-cured adhesive resin cements to dentin. Materials and Methods: Twelve freshly extracted intact human mandibular molars were selected for this study and stored in the saline solution. Three of the axial surfaces of the teeth were prepared to obtain flat dentinal surfaces. Thirty-six ceramic disks (4-mm diameter, 2-mm thick) were constructed from a pressable glass-ceramic (Vision). The discs were etched with hydrofluoric acid and primed, and then divided into two equal groups, groups I and II (n = 18 each). Two adhesive systems were used following manufacturer's instructions. The discs of group I were bonded to the conditioned dentin surface using adhesive resin (Rely X Veneer), and group II discs were bonded to dentin using Rely X ARC. For each group, the resin was cured using three modes (fast, ramp, pulse). Interfacial gap at the dentin/resin interface was measured at eight predetermined sites for each specimen using a stereomicroscope, and shear bond strength of the bonded specimens was carried out using a universal testing machine. Results: Ramp-cured specimens recorded significantly higher mean shear bond strengths for both dual-and light-polymerized resins than those with fast and pulse modes. Moreover, fewer interfacial gaps were found at the resin/dentin interface in association with ramp cure modes of both resins. Most failures were adhesive failures at the dentin-resin luting agent (RLA) interface in specimens polymerized using highpowered LED fast or pulse modes, while a cohesive failure pattern within the resin was associated with the ramp-curing mode. Conclusion: Within the limitations of this study, the shear bond strength of an RLA to dentin was found to be enhanced with light-or dual-polymerized adhesive resin using an LED light in ramp mode, whereas shear bond strength was significantly lower when polymerized using LED in fast or pulse modes.

Journal of Prosthodontics, 2009

Purpose: This study evaluated the effect of artificial saliva storage on the hardness, crack leng... more Purpose: This study evaluated the effect of artificial saliva storage on the hardness, crack length, and fracture toughness of a glazed, polished, and bleached hydrothermal low-fusing glass-ceramic (Duceram LFC). Materials and Methods: Forty ceramic discs were constructed. The discs were assigned to four groups (n = 10) according to their surface finish: Gp1-Autoglaze, Gp2-Autoglaze/ground/diamond-polished, Gp3-Overglaze, Gp4-Overglaze/ground/diamond-polished. Each group was further divided into two subgroups forming eight total subgroups (n = 5). Subgroup A was unbleached; Subgroup B was bleached. Testing was performed before and after 21 days of artificial saliva storage. Data were presented as means and standard deviation (SD). ANOVA was used, along with Duncan's post hoc test for pairwise comparison between the means when ANOVA test was found significant (p ≤ 0.05). Results: Surface treatments such as glazing, polishing, and bleaching, saliva storage, and the interaction between these variables had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness of the specimens. There was a statistically significant increase in microhardness and fracture toughness mean values, while crack length values decreased after saliva storage. Polished specimens recorded the smallest crack lengths and fracture toughness, and highest hardness values before and after saliva storage. No difference in fracture toughness values was evident between glazed and polished specimens. Mean crack lengths decreased after saliva storage in all the tested specimens. Hardness values increased after saliva storage. The autoglazed group showed significantly higher fracture toughness, lower crack length, and microhardness than the overglazed group. Conclusions: Surface finishing procedures and artificial saliva storage had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness. This in vitro study suggests that fracture toughness of ceramics may be affected by different surface treatments such as glazing, polishing, bleaching, or a combination; however, in this study Duceram LFC proved its self-healing property after 3-week storage in artificial saliva.

Journal of Prosthodontics, 2009

Purpose: This study examined the effect of a manufacturer's proposed bleaching protocol on surfac... more Purpose: This study examined the effect of a manufacturer's proposed bleaching protocol on surface properties of a low-fusing ceramic. Materials and Methods: Forty ultra low-fusing ceramic samples (Ducera LFC) were constructed for this study. Half the discs were autoglazed, and the other half were overglazed. The two main groups (autoglaze, overglaze) were further divided into subgroups of four. Group I: autoglazed (control group I), bleached autoglaze, diamond polished, diamond polished and bleached. The same division was applied to Group II: overglazed (control group II), bleached overglazed, diamond polished, diamond polished and bleached. The total number of subgroups was eight. Control groups I and II (n = 10) were both immersed in distilled water, which was changed daily for 1 week. The other six subgroups (n = 30) were subjected to the following protocol: 2-hour bleaching using carbamide peroxide 35%, followed by six 8-hour bleaching applications using 15% carbamide peroxide gel. Every two bleaching procedures were interrupted by a 10-hour fluoride gel application. At the end of each bleaching step, the treated specimens were washed under running water in readiness for the next application. Results: Bleaching did not significantly affect the surface roughness of the autoglazed group; however, it significantly increased the roughness of the overglazed ceramic, especially after polishing. Regarding whiteness, the overglazed group had significantly increased values compared to the autoglazed group. It appeared that bleaching whitened the overglazed specimens significantly, whereas polishing alone showed less whiteness. There appeared to be a strong inverse relation between the roughness and the whiteness of the autoglazed specimens as affected by the bleaching. On the other hand, a weak inverse relation was found between the roughness and whiteness of the overglazed specimens, as affected by the bleaching. Conclusions: In-office bleaching with 35% carbamide peroxide, followed by home bleaching with 15% carbamide peroxide and a fluoride gel may affect the roughness and whiteness of overglazed and polished/overglazed Duceram LFC restorations. No significant change in roughness or whiteness was detected by this bleaching system on autoglazed Ducera LFC. Ceramic restorations should be protected before any bleaching for fear of altering their roughness and whiteness. Patients should be advised that their existing porcelain restorations may not match their natural teeth after bleaching.

Journal of Prosthodontics, 2011

Purpose: This article reviews a press-on metal (POM) ceramic versus a conventional veneering syst... more Purpose: This article reviews a press-on metal (POM) ceramic versus a conventional veneering system regarding marginal gaps, fracture resistance, microhardness, and surface roughness. This was done to provide clinical recommendations for its use. Materials and Methods: Forty crowns were constructed and divided into two main groups according to the metal coping design. Group 1: Twenty metal copings with metal margin extending to the axiogingival line angle. Group 2: Twenty metal copings with metal margin 1 mm occlusal to the axiogingival line angle. The specimens of each group were further subdivided into two subgroups (A and B) according to the veneering porcelain used. The vertical marginal gaps of the crowns were measured after veneering placement. For fracture resistance testing, the crowns were subjected to compressive load to failure. Representative samples of the two main groups were selected to measure surface roughness and microhardness. Results: No statistically significant difference was evident regarding the vertical marginal gap distance in relation to the margin design of both tested groups (p = 0.249, p = 0.815); however, the POM veneer group with metal porcelain margin showed statistically lower marginal gaps than the conventional ceramic veneer group (p = 0.043). Fracture resistance values did not show statistically significant difference regarding the margin design (p = 0.858, p = 0.659) or type of the ceramic veneer material (p = 0.592, p = 0.165). Both groups showed no significant difference in their mean roughness values (p = 0.235). Conventional ceramics showed statistically significantly higher mean microhardness values than POM did (p = 0.008). Conclusion: This study showed superior marginal adaptation, decreased microhardness, and similar load to failure and roughness values of the POM ceramic system. Moreover, considerable ease and speed of fabrication of this system were evident. The high variation in range values of some tested groups is among the limitations of this study, along with the lack of clinical trials to test the system in vivo.

Journal of Prosthodontics, 2010

Purpose: This study was designed to evaluate three veneering materials for an allceramic alumina ... more Purpose: This study was designed to evaluate three veneering materials for an allceramic alumina system in terms of bond strength, microhardness, and core/veneer interface quality. Materials and Methods: Fifteen In-Ceram cores were constructed for this study, forming three groups of five specimens each divided by the veneering ceramic disc fired on the occlusal surface of the alumina core: Vitadur N, Vitadur Alpha, or VM7. The specimens underwent shear bond and microhardness testing. Gross examination of debonded discs by SEM and EDAX analysis was conducted. Data for shear bond strength (SBS) and microhardness were presented as means and standard deviation (SD) values. One-way ANOVA and Duncan's post hoc test were used for pairwise comparison between the means when ANOVA test was significant. Results: VM7 showed the highest shear bond value and lowest microhardness values of the three tested veneering materials. No statistically significant difference was evident between the SBSs of Vitadur N and Vitadur Alpha to the alumina cores. Vitadur Alpha showed statistically the highest mean VHN, followed by Vitadur N, while VM7 showed statistically the lowest mean values of VHN. Conclusions: In-Ceram core/Vitadur N disc debondings appeared to be interfacial by complete delaminations, leaving a shiny visible and quite distinct area, whereas there appeared to be perfect adhesion between the core and VM7 veneering material. VM7 appeared to possess ultra-fine texture with intimate contact to the core, forming what seemed like a transition zone where the ceramic and core appeared to blend for a distance. VM7's finer particle size has improved the core/veneer bond strength and decreased micohardness values. This new veneering material will probably enhance the performance and esthetics of the In-Ceram system.

The Journal of Prosthetic Dentistry, 2008

Statement of problem. Bonding ceramic restorations to tooth structure relies on treatment of the ... more Statement of problem. Bonding ceramic restorations to tooth structure relies on treatment of the ceramic intaglio surface, selection of a suitable resin luting agent, and appropriate treatment of prepared tooth structure. Various ceramic surface treatments have been advocated which produce different topographies and bond strengths, but little information is available to identify the interaction between the resulting surface topography and bond strength. Purpose. The purpose of this in vitro study was to evaluate the effect of surface treatments on surface roughness and bond strength to dentin and enamel of a commercially available heat-pressed dental ceramic (IPS Empress). Material and methods. One hundred heat-pressed ceramic disks were fabricated according to the manufacturer's recommendations. Specimens were divided into 5 groups (n=20) and treated with 1 of the following: (1) etching with 9.5% hydrofluoric acid, (2) 50%, or (3) 60% orthophosphoric acid and airborne-particle abrasion with (4) 50-µm, or (5) 250-µm alumina for 10 seconds. Morphological changes obtained with the surface treatments were investigated with a surface texture analyzer on half of the treated specimens. Two additional specimens from each group were treated and prepared for scanning electron microscopy. The specimens were then used for a bond strength test. The treated specimens were silanated and luted with a composite resin luting agent (Nexus 2) to enamel (n=50) and dentin (n=50) surfaces with 10 specimens for each treatment group. The luted specimens were loaded to failure in a universal testing machine in the shear mode with a crosshead speed of 0.05 mm/min. The data were analyzed with 1-way ANOVA followed by the Ryan-Einot-Gabriel-Welsch Multiple Range Test (α=.05). Results. Surface treatments resulted in significant differences for surface topography and shear bond strength (P<.001). Mean surface roughness (Ra) (SD) was (2.54 (0.21) µm) for ceramic surfaces treated with 50-µm aluminum powder. Treatment of ceramic specimens with 50% orthophosphoric acid appeared to result in a smoother surface (1.02 (0.38) µm). The highest mean bond strength (SD) to enamel (14.7 (0.6) MPa) and dentin (8.2 (1.5) MPa) was associated with hydrofluoric acid etching. The lowest mean bond strength (SD) to enamel (2.7 (0.8) MPa) and dentin (1.5 (0.1) MPa) was recorded for 50% phosphoric acid. Conclusions. Hydrofluoric acid treatment resulted in the generation of pores and grooves that produced the greatest bond strength between the ceramic and tooth dentin and enamel. Orthophosphoric acid treatment was the least effective surface treatment method evaluated. The results are applicable to only the all-ceramic/luting system evaluated.

Journal of Prosthodontics, 2010

Purpose: This study was undertaken to assess the influence of three-veneering materials on the ma... more Purpose: This study was undertaken to assess the influence of three-veneering materials on the marginal fit, fracture resistance, and failure pattern of In-Ceram alumina crowns. Materials and Methods: Forty In-Ceram cores were constructed and divided into four groups of ten each. Ten alumina cores were left unveneered, forming the first group for core testing, while the other 30 copings were divided into three groups depending on the veneering material used. The vertical marginal gaps of the alumina copings were measured before and after veneer placement at 16 sites using an optical microscope. The specimens were then loaded to fracture at a crosshead speed of 1 mm/min. Fractured specimens were examined, and the fracture patterns of the crowns were recorded. Selected specimens were examined using scanning electron microscope. Data were presented as means and standard deviation values. One-way ANOVA was used to compare between mean gap areas and fracture resistance of the three materials. Duncan's post hoc test was used for pairwise comparison between the means when ANOVA test was significant. Results: Vitadur-N-veneered crowns showed statistically the highest mean vertical gaps, while no significant difference was evident between the marginal fits of Vitadurαand VM7-veneered crowns. Regarding the strength, a statistically significant decrease in fracture resistance of the cores was evident after veneering with Vitadur-N; however, no significant change in mean fracture resistance value of Vitadur-α-and VM7-veneered crowns was evident compared to the alumina cores. VM7-veneered crowns showed the highest fracture resistance values. Conclusions: Vitadur-N-veneered crowns showed the highest mean vertical gaps and the lowest mean fracture resistance values of the tested groups, while VM7-veneered crowns combined the highest fracture resistance values and clinically acceptable margins. The best interface quality and finest ceramic texture were evident in case of VM7 material. An ideal all-ceramic restoration, which combines excellent physical properties, marginal fit, and esthetics, is the goal of the dental profession. Reinforced all-ceramic restorations are mostly composed of layered structures with a high-strength core material, laminated with esthetic but weak veneer porcelains. 1 Glass-infiltrated sintered alumina (In-Ceram, Vita Zahnfabrik, Bad Sackingen, Germany), one of these many systems, is based on the slip casting of an alumina core with its subsequent glass infusion. This core material is veneered with esthetic feldspathic porcelain. The partially sintered porous core is composed of 85% Al 2 O 3 , which is subsequently infiltrated with molten lanthanum glass infiltration in a second-firing process. It reaches a flexural strength of approximately 400 MPa. 2-4