Talal Alnassar

Efficacy of novel cleansing agent for the decontamination of lithium disilicate ceramics: a shear bond strength study

Abstract Purpose: To investigate the efficacy of Ivoclean as a ceramic cleansing agent, by assessing shear bond strength of pre-etched lithium disilicate (LD) ceramic to resin cement. Materials and Methods: Seventy LD discs (10 × 10 × 4 mm) were fabricated and etched using 5% hydrofluoric acid (HF) for 20 s. Ten specimens were not exposed to saliva and silicone disclosing medium (negative control). The other 60 specimens, divided into six groups (n = 10), were exposed to saliva for 20 s and silicone disclosing medium for 3 min. Following contamination, 10 specimens were not cleansed (positive control). The remaining five groups were exposed to one of the five different cleansing agents: 96% isopropanol, 37% phosphoric acid-30 s, 5% HF acid- 20 s, 5% HF acid- 120 s, and Ivoclean paste-20 s. All specimens were treated with primer and bonded to a self-curing resin cement. Before shear bond strength testing, all specimens were thermocycled (3000 cycles; 5–55°). Results: Contamination of pre-etched LD ceramic specimens significantly reduced the shear bond strength values from 22.39 ± 0.38 MPa (negative control) to 6.54 ± 0.90 MPa (positive control) (p < 0.05). Cleansing of contaminated ceramic specimens with 5% HF acid [20 s (19.28 ± 1.06 MPa) and 120 s (20.04 ± 1.09 MPa)] and Ivoclean (18.30 ± 0.97) provided significantly higher bond strength values than other cleansing methods with 37% phosphoric acid and 96% isopropanol (p < 0.05). Conclusion: Ivoclean and 5% HF acid were found to be effective in cleansing of LD ceramic surface by demonstrating maximum increase in shear bond strength values as compared to contaminated LD ceramics.

The current considerations in the fabrication of implant prostheses and the state of prosthetic complications: A survey among the dental technicians

Purpose To investigate the current considerations in the fabrication of dental implant prostheses (DIP) and the state of prosthetic complications from the dental technicians (DT) perspective. Methods A self-designed pretested questionnaire and an informed consent were distributed to 150 certified DT working in dental laboratories of Riyadh, KSA. The demographic data, questions related to the implant fixed/removable prostheses and questions on the prosthetic complications related to the DIP were collected. Descriptive statistics and Chi-square test were used for statistical analysis, considering a P-value of <0.05 using SPSS. Results 130 responses (response rate 83.6%) were received. 53% (n = 69) of the DT received job orders for DIP from >20 dentists. 49% (n = 64) of dentists took the leading role in the treatment planning/designing. 48% (n = 62) and 52% (n = 68) of requests were for Cement and Screw retained DIP respectively. Custom abutments 37% (n = 49) choice of abutments. Porcelain fused to metal (PFM) 34% (n = 44) and PFM with metal occlusal surface 55% (n = 71) were material of choice. 49% (n = 64) designing of implant overdentures were according to the dentist’s instructions with Ball and Socket 48% (n = 63) to be the most common attachment. DT regarded poor implant location/orientation 38% (n = 49) and inaccuracies in impression/bite-registration 40% (n = 52) as the obstacles to success. Half 50% (n = 65) of the repairs were for facing damage/chipping of ceramic. Fracture of the denture base/tooth detachment 50% (n = 65) was common with implant over dentures. Conclusions DT played a role and took decisions regarding the DIP. Frequent problems found by DT were poor implant location, discrepancies in impression/bite-registration, facing damage/chipping and damage/fracture of the denture base/prosthetic teeth. The frequency of these complications can be minimized by an increase in the prosthetic knowledge of the dentists and establishing clear protocols for communication between the dentist and the DT.

Staged extractions and implant placement in a periodontally compromised patient: A clinical report

Staging the extraction of selected teeth in a periodontally compromised patient during complete mouth rehabilitation has advantages, including avoiding a transitional complete denture, keeping the patient with a fixed prosthesis throughout the treatment without the need to immediately load the implants, maintaining the interdental papillae, and providing comfort for the patient. The need for a multistep extended treatment and additional cost are the main disadvantage of this approach. This clinical report describes the clinical steps and follow-up of a staging approach and implant placement in a periodontally compromised patient with excessive gingival display to achieve a good functional and esthetic result.

Injectable technique for direct provisional restoration

OBJECTIVE New technique describes an alternative treatment modality of making direct provisional restoration. CLINICAL CONSIDERATIONS A preoperative wax-up should be fabricated, followed by fabrication of a transparent polyvinyl siloxane (VPS) matrix in a clear plastic prefabricated tray with retentive holes. After the tray is separated from the model, two additional holes will be made through the tray and the VPS for injecting and venting of the temporary resin. After the teeth are prepared and the separating medium applied to them, the resin should be injected into the entrance hole using the provided auto-mix cartilage tip. The flow of the resin around the preparation can be observed through the clear mold and once the resin starts to extrude from the exit hole. It is necessary to block the exit hole with a finger while continuing to inject. This will increase the pressure inside the mold and improve marginal adaptation. Before complete polymerization, the matrix is removed. The provisional restorations are removed from the matrix and contoured, adjusted, and polished. CONCLUSION This technique will help the clinicians to enhance the quality of the provisional restorations, to prevent entrapment of bubbles, improve marginal precision and prevent seating error. CLINICAL SIGNIFICANCE This study described a novel technique for constructing a direct provisional restoration by injecting bis-acryl temporary resin into a matrix that is already seated over the prepared tooth.

Shear bond strength of bis-acryl resin provisional material repaired using a flowable composite

Abstract This study investigated the shear bond strength of a bis-acryl composite repaired with a flowable composite after different surface treatments. Sixty standardized cylindrical silicone molds were filled with bis-acryl resin provisional material and then divided into six groups (n = 10 per group) to undergo different surface treatments. After a surface treatment had been performed, the flowable composite was injected directly into the cylinder of each specimen, and the specimens were then cured over a 10-mm-thick glass slide for 20 s. The shear bond strength was determined using a universal testing machine at a crosshead speed of 1.0 mm/min by placing a knife-edged blade immediately adjacent and parallel to the adhesive interface between the repair material (flowable composite) and the bis-acryl resin provisional material. The mean shear bond strengths ranged from 8.98 to 17.14 MPa. The highest mean shear bond strength corresponded to the bonding group (17.14 MPa), whereas the air-particle abrasion group exhibited the lowest mean shear bond strength (8.98 MPa). Surface treatment of bis-acryl resins with bonding appears to be a promising approach for improving repair bond strength, and the bonding group exhibited the highest levels of bond strength.

Impact of Denture Cleansing Solution Immersion on Some Properties of Different Denture Base Materials: An In Vitro Study: Immersion Impact of Denture Cleansing Agents

Purpose To evaluate the effect of several denture cleansing solutions on the color stability, surface roughness, and flexural strength of three denture base materials. Materials and Methods Twenty-seven specimens were prepared using heat-polymerized (HP) denture base material, 27 using autopolymerized (AP) denture base material, and 27 using visible-light-polymerized (VLP) denture base, creating a total of 81 specimens. The specimens were randomly divided into three groups (n = 27): the distilled water group (DWG), Corega group (CG), and Renew group (RG). Color changes (ΔE), surface roughness (Ra, nm), and flexural strength (MPa) of each specimen were measured using a spectrophotometer, an optical profilometer, and a universal testing machine, respectively. The results were statistically analyzed using a one-way ANOVA and a post hoc Tukeys test (α = 0.05). Results The only statistically significant color change detected was in the VLP resin treated with Corega and Renew. There was a significant increase in the surface roughness of all denture resin groups after immersion in Corega. Immersion in Renew significantly increased surface roughness only in the HP and AP specimens. The only significant reduction in flexural strength was detected in the HP resin after immersion in Corega (p < 0.05). Conclusions Within the limitations of this study, it can be concluded that Corega has a significantly greater negative impact than distilled water on the flexural strength of HP resin base materials. Renew significantly increased the surface roughness of AP and HP, while Corega increased the surface roughness of all resin materials.PURPOSE To evaluate the effect of several denture cleansing solutions on the color stability, surface roughness, and flexural strength of three denture base materials. MATERIALS AND METHODS Twenty-seven specimens were prepared using heat-polymerized (HP) denture base material, 27 using autopolymerized (AP) denture base material, and 27 using visible-light-polymerized (VLP) denture base, creating a total of 81 specimens. The specimens were randomly divided into three groups (n = 27): the distilled water group (DWG), Corega group (CG), and Renew group (RG). Color changes (ΔE), surface roughness (Ra, nm), and flexural strength (MPa) of each specimen were measured using a spectrophotometer, an optical profilometer, and a universal testing machine, respectively. The results were statistically analyzed using a one-way ANOVA and a post hoc Tukeys test (α = 0.05). RESULTS The only statistically significant color change detected was in the VLP resin treated with Corega and Renew. There was a significant increase in the surface roughness of all denture resin groups after immersion in Corega. Immersion in Renew significantly increased surface roughness only in the HP and AP specimens. The only significant reduction in flexural strength was detected in the HP resin after immersion in Corega (p < 0.05). CONCLUSIONS Within the limitations of this study, it can be concluded that Corega has a significantly greater negative impact than distilled water on the flexural strength of HP resin base materials. Renew significantly increased the surface roughness of AP and HP, while Corega increased the surface roughness of all resin materials.

Impact of Denture Cleansing Solution Immersion on Some Properties of Different Denture Base Materials: An In Vitro Study

Purpose To evaluate the effect of several denture cleansing solutions on the color stability, surface roughness, and flexural strength of three denture base materials. Materials and Methods Twenty-seven specimens were prepared using heat-polymerized (HP) denture base material, 27 using autopolymerized (AP) denture base material, and 27 using visible-light-polymerized (VLP) denture base, creating a total of 81 specimens. The specimens were randomly divided into three groups (n = 27): the distilled water group (DWG), Corega group (CG), and Renew group (RG). Color changes (ΔE), surface roughness (Ra, nm), and flexural strength (MPa) of each specimen were measured using a spectrophotometer, an optical profilometer, and a universal testing machine, respectively. The results were statistically analyzed using a one-way ANOVA and a post hoc Tukeys test (α = 0.05). Results The only statistically significant color change detected was in the VLP resin treated with Corega and Renew. There was a significant increase in the surface roughness of all denture resin groups after immersion in Corega. Immersion in Renew significantly increased surface roughness only in the HP and AP specimens. The only significant reduction in flexural strength was detected in the HP resin after immersion in Corega (p < 0.05). Conclusions Within the limitations of this study, it can be concluded that Corega has a significantly greater negative impact than distilled water on the flexural strength of HP resin base materials. Renew significantly increased the surface roughness of AP and HP, while Corega increased the surface roughness of all resin materials.PURPOSE To evaluate the effect of several denture cleansing solutions on the color stability, surface roughness, and flexural strength of three denture base materials. MATERIALS AND METHODS Twenty-seven specimens were prepared using heat-polymerized (HP) denture base material, 27 using autopolymerized (AP) denture base material, and 27 using visible-light-polymerized (VLP) denture base, creating a total of 81 specimens. The specimens were randomly divided into three groups (n = 27): the distilled water group (DWG), Corega group (CG), and Renew group (RG). Color changes (ΔE), surface roughness (Ra, nm), and flexural strength (MPa) of each specimen were measured using a spectrophotometer, an optical profilometer, and a universal testing machine, respectively. The results were statistically analyzed using a one-way ANOVA and a post hoc Tukeys test (α = 0.05). RESULTS The only statistically significant color change detected was in the VLP resin treated with Corega and Renew. There was a significant increase in the surface roughness of all denture resin groups after immersion in Corega. Immersion in Renew significantly increased surface roughness only in the HP and AP specimens. The only significant reduction in flexural strength was detected in the HP resin after immersion in Corega (p < 0.05). CONCLUSIONS Within the limitations of this study, it can be concluded that Corega has a significantly greater negative impact than distilled water on the flexural strength of HP resin base materials. Renew significantly increased the surface roughness of AP and HP, while Corega increased the surface roughness of all resin materials.

In Vitro Evaluation of the Inhibitory Activity of Thymoquinone in Combatting Candida albicans in Denture Stomatitis Prevention

Candida albicans adhesion and proliferation on denture bases may lead to denture stomatitis, which is a common and recurrent problem in denture wearers. The goal of this study was to assess the inhibitory effect of thymoquinone incorporated in the polymethyl methacrylate denture base material against Candida albicans. Eighty acrylic resin specimens were fabricated and divided into eight groups (n = 10) according to thymoquinone concentrations of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and 5% of acrylic powder. Two methods were used to evaluate the effect of thymoquinone on Candida albicans: the slide count and the serial dilution test. A multivariate analysis of variance (MANOVA) and the post-hoc Tukey’s Honestly Significant Difference (HSD) test were performed to compare the difference of means between the observations taken at various intervals with baseline. The p value was statistically significant at ≤0.05. According to the slide count and the serial dilution test, the mean number of adhered Candida albicans in the control group was 5436.9 ± 266 and 4691.4 ± 176.8; however, this number dramatically decreased to 0 ± 0 and 32.4 ± 1.7 in group 8 (concentration 5%). These results suggest that the incorporation of thymoquinone into the acrylic resin denture base material might be effective in preventing Candida albicans adhesion.

Effect of different ceramic primers on shear bond strength of resin-modified glass ionomer cement to zirconia

Abstract Purpose: This study evaluated and compared the effect of different ceramic primers on the shear bond strength of RMGIC to zirconia with and without air-particle abrasion. Material and Methods: 120 zirconia square specimens (5 mm × 5 mm × 2 mm) were fabricated. Half of the specimens were air-particle abraded (A) and the other half were left untreated (NA). Both groups were further divided into six subgroups (n = 10). Composite cylinders (2.9 mm × 3.0 mm) were fabricated and bonded to the zirconia samples with RMGIC (RelyX Plus) after different priming methods: no ceramic primer (group NS); Z-Prime (group ZP); Clearfil ceramic primer (group CP); cleaned with Ivoclean then Monobond plus (IV/MS); Monobond plus (group MS); and Rely X ceramic primer (group RX). Specimens were rinsed, stored in distilled water, and thermocycled (TC) for 10,000 cycles between 5 and 60 °C with a dwell time of 15s. Data were analyzed with two-way ANOVA and the Tukey–Kramer method test (a = .05). Results: air-particle abrasion significantly affected bond strength of RMGIC to zirconia regardless of the primer used (p < 0.001 for all primers and the control). After TC, A-ZP (11.1 ± 0.6 MPa), A-CP (11.9 ± 0.6 MPa), and A-MS (11.9 ± 0.5 MPa) revealed the highest shear bond strength values, while NA-NS (2.9 ± 0.3 MPa) and NA-RX (4.7 ± 0.5 MPa) had the lowest. Failure modes were primarily adhesive. Conclusion: air-particle abrasion with aluminum oxide and application of MDP-based ceramic primers provide the highest bond strength of RMGIC to zirconia.

Implementation of Digital Dentistry to Rehabilitate a Mutilated Dentition With Implant Fixed Prostheses: A Clinical Report

T ooth loss can adversely affect esthetics and function and can lead to multiple complications. Drifting and/ or tipping of teeth adjacent to edentulous spaces, overeruption of opposing teeth, bone loss, irregular occlusal plan, and loss of a restorative space are common complications of partial edentulism. Subsequently, functional and esthetic rehabilitation will be complicated and may require invasive procedures such as crown lengthening, orthodontics, full-mouth extraction of remaining teeth, alveoplasty, and restorations with implants to support removable or fixed prostheses. Anatomical limitations such as narrow ridges and an inferior alveolar nerve present a challenge for ideal implant placement. Certainly, the introduction of computerized tomography (CT) scan and 3-dimentional planning software facilitates treatment planning and guided surgeries for predictable implant placements in relation to tissue structures and prospective prostheses. Preprosthetic surgeries can help overcome anatomic limitations such as irregular and/or narrow alveolar ridges prior to or at the same visit as implant placement. This case report demonstrates the use of computer-assisted treatment planning and computer-aided fabrication of surgical guides for alveoplasty and proper implant positions at the same visit to rehabilitate a mutilated dentition with cementable segmented implant fixed prostheses.