Publications by authors named "Ra'fat I Farah"

8 Publications

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Effect of ambient lighting conditions on tooth color quantification in cross-polarized dental photography: A clinical study.

J Prosthet Dent 2021 Feb 24. Epub 2021 Feb 24.

Associate Professor, Department of Orthodontic and Pediatric Dentistry, College of dentistry, Qassim University, Al-Mulida, Qassim, KSA.

Statement Of Problem: Limited data are available in the dental literature regarding the effect of ambient lighting on the consistency of color quantification in cross-polarized photography.

Purpose: The purpose of this clinical study was to investigate the effects of ambient lighting conditions and postprocessing photograph calibration on color quantification in cross-polarized dental photography.

Material And Methods: Twelve volunteers with intact maxillary central incisors were recruited. Cross-polarized photographs were captured under light-emitting diode (LED), fluorescent ceiling, and natural lighting. The photographs were repeated after a 1-week interval, yielding a total of 72 photographs. The average Commission Internationale de l'Eclairage L∗a∗b∗ coordinates of the right central incisor were obtained with a software program before and after calibration by using a neutral gray reference card. The color difference (ΔE) values were calculated for each participant between the repeated photographs under the change and no change in illumination both before and after calibration. A 3-way repeated measures ANOVA was used to compare these values (α=.05).

Results: A statistically significant 3-way interaction was found between the illuminant type, change in illumination, and calibration (P<.001); however, all the ΔE values were within a clinically acceptable threshold (ΔE≤3.7). Before calibration, when photographs were captured under no change in illumination, LED lighting was found to have a significantly lower ΔE than fluorescent (P=.008) and natural and fluorescent lightings (P=.011), but when there was a change in illumination, no significant differences (P>.05) were found. After calibration, all the ΔE values were ≤1 and significantly lower than the values before calibration (P<.001).

Conclusions: Both the ambient illuminant type and change in illumination had minimal effects on ΔE. Calibration through the use of a neutral gray reference card was found to result in reduced and imperceptible color change (ΔE≤1) for all illuminant types.
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http://dx.doi.org/10.1016/j.prosdent.2021.01.015DOI Listing
February 2021

Fabrication of Custom Post-And-Core Using a Directly Fabricated Silicone Pattern and Digital Workflow.

J Prosthodont 2020 Aug 2;29(7):631-635. Epub 2020 Jul 2.

Department of Orthodontics and Pediatric Dentistry, College of dentistry, Qassim University, Al-Mulaydah, Qassim, KSA.

This report introduces an alternative clinical and laboratory technique for the direct fabrication of a custom post-and-core pattern using poly (vinyl siloxane) (PVS) occlusal registration material, followed by a digital workflow. This technique decreases chairside time, eliminates the risk of locking the pattern into the postspace and improves accuracy of the custom post-and-core.
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http://dx.doi.org/10.1111/jopr.13218DOI Listing
August 2020

The use of sectional matrix in direct restoration of a structurally compromised posterior tooth: a clinical technique.

Quintessence Int 2019 ;50(9):680-684

This report describes a clinical technique to facilitate the placement of direct composite resin restorations in structurally compromised posterior teeth, to restore proper anatomical contours and interproximal contacts using sectional matrix kit and thermoplastic impression material.
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http://dx.doi.org/10.3290/j.qi.a42952DOI Listing
November 2019

Effect of cooling water temperature on the temperature changes in pulp chamber and at handpiece head during high-speed tooth preparation.

Authors:
Ra'fat I Farah

Restor Dent Endod 2019 Feb 24;44(1):e3. Epub 2018 Dec 24.

Department of Prosthodontics, College of Dentistry, Qassim University, Al-Buraydah, Qassim, Saudi Arabia.

Objectives: It was the aim of this study to evaluate the effect of cooling water temperature on the temperature changes in the pulp chamber and at the handpiece head during high-speed tooth preparation using an electric handpiece.

Materials And Methods: Twenty-eight intact human molars received a standardized occlusal preparation for 60 seconds using a diamond bur in an electric handpiece, and one of four treatments were applied that varied in the temperature of cooling water applied (control, with no cooling water, 10°C, 23°C, and 35°C). The temperature changes in the pulp chamber and at the handpiece head were recorded using K-type thermocouples connected to a digital thermometer.

Results: The average temperature changes within the pulp chamber and at the handpiece head during preparation increased substantially when no cooling water was applied (6.8°C and 11.0°C, respectively), but decreased significantly when cooling water was added. The most substantial drop in temperature occurred with 10°C water (-16.3°C and -10.2ºC), but reductions were also seen at 23°C (-8.6°C and -4.9°C). With 35°C cooling water, temperatures increased slightly, but still remained lower than the no cooling water group (1.6°C and 6.7ºC).

Conclusions: The temperature changes in the pulp chamber and at the handpiece head were above harmful thresholds when tooth preparation was performed without cooling water. However, cooling water of all temperatures prevented harmful critical temperature changes even though water at 35°C raised temperatures slightly above baseline.
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http://dx.doi.org/10.5395/rde.2019.44.e3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387888PMC
February 2019

A technique to facilitate ceramic veneer cementation.

J Prosthet Dent 2018 Aug 8;120(2):194-197. Epub 2018 Mar 8.

Predoctoral student, College of Dentistry, Qassim University, Kingdom of Saudi Arabia, Qassim, Saudi Arabia.

This report describes a technique to facilitate ceramic veneer cementation. By stabilizing a ceramic veneer in its fully seated position with miniature wooden spring clips before resin polymerization, excess luting resin cement can be removed from ceramic veneer margins without the risk of veneer dislodgement or fracture.
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http://dx.doi.org/10.1016/j.prosdent.2017.09.021DOI Listing
August 2018

Microleakage of Glass Ionomer-based Provisional Cement in CAD/CAM-Fabricated Interim Crowns: An in vitro Study.

J Contemp Dent Pract 2016 Oct 1;17(10):801-806. Epub 2016 Oct 1.

Department of Prosthodontics, College of Dentistry, Qassim University, Al-Mulaydah, Qassim, Kingdom of Saudi Arabia.

Aim: The aim of this study was to compare in vitro the marginal microleakage of glass ionomer-based provisional cement with resin-based provisional cement and zinc oxide non-eugenol (ZONE) provisional cement in computer-aided design and computer-aided manufacturing (CAD/CAM)-fabricated interim restorations.

Materials And Methods: Fifteen intact human premolars were prepared in a standardized manner for complete coverage of crown restorations. Interim crowns for the prepared teeth were then fabricated using CAD/CAM, and the specimens were randomized into three groups of provisional cementing agents (n = 5 each): Glass ionomer-based provisional cement (GC Fuji TEMP LT™), bisphenol-A-glycidyldimethacrylate (Bis-GMA)/ triethylene glycol dimethacrylate (TEGDMA) resin-based cement (UltraTemp® REZ), and ZONE cement (TempBond NE). After 24 hours of storage in distilled water at 37°C, the specimens were thermocycled and then stored again for 24 hours in distilled water at room temperature. Next, the specimens were placed in freshly prepared 2% aqueous methylene blue dye for 24 hours and then embedded in autopolymerizing acrylic resin blocks and sectioned in buccolingual and mesiodistal directions to assess dye penetration using a stereomicroscope. The results were statistically analyzed using a nonparametric Kruskal-Wallis test. Dunn's post hoc test with a Bonferroni correction test was used to compute multiple pairwise comparisons that identified differences among groups; the level of significance was set at p < 0.05.

Results: All groups exhibited marginal microleakage; the Bis-GMA/TEGDMA resin-based provisional cement demonstrated the lowest microleakage scores, which were statistically different from those of the glass ionomer-based provisional cement and the ZONE cement.

Conclusion: The provisional cementing agents exhibited different sealing abilities. The Bis-GMA/TEGDMA resin-based provisional cement exhibited the most effective favorable sealing properties against dye penetration compared with the glass ionomer-based provisional cement and conventional ZONE cement.

Clinical Significance: Newly introduced glass ionomer-based provisional cement proved to be inferior to resin-based provisional cement as far as marginal microleakage is concerned.
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http://dx.doi.org/10.5005/jp-journals-10024-1934DOI Listing
October 2016

Technique to verify the accuracy of a definitive cast before the fabrication of a fixed dental prosthesis.

J Prosthet Dent 2016 Sep 5;116(3):325-7. Epub 2016 May 5.

Intern, College of Dentistry, Qassim University, Qassim, Saudi Arabia.

This report describes a straightforward technique for verifying the accuracy of a definitive cast by using a maximal intercuspation record fabricated from polyvinyl siloxane occlusal registration material. This precise verification method detects inaccurate casts before the dental prosthesis is fabricated, thus saving chairside and laboratory time while reducing the number of costly prosthesis remakes.
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http://dx.doi.org/10.1016/j.prosdent.2016.03.010DOI Listing
September 2016

Agreement between digital image analysis and clinical spectrophotometer in CIEL*C*h° coordinate differences and total color difference (ΔE) measurements of dental ceramic shade tabs.

Authors:
Ra'fat I Farah

Int J Esthet Dent 2016 ;11(2):234-45

Objectives: The objectives of this in vitro study were: 1) to test the agreement among color coordinate differences and total color difference (ΔL*, ΔC*, Δh°, and ΔE) measurements obtained by digital image analysis (DIA) and spectrophotometer, and 2) to test the reliability of each method for obtaining color differences.

Materials And Methods: A digital camera was used to record standardized images of each of the 15 shade tabs from the IPS e.max shade guide placed edge-to-edge in a phantom head with a reference shade tab. The images were analyzed using image-editing software (Adobe Photoshop) to obtain the color differences between the middle area of each test shade tab and the corresponding area of the reference tab. The color differences for the same shade tab areas were also measured using a spectrophotometer. To assess the reliability, measurements for the 15 shade tabs were repeated twice using the two methods. The Intraclass Correlation Coefficient (ICC) and the Dahlberg index were used to calculate agreement and reliability.

Results: The total agreement of the two methods for measuring ΔL*, ΔC*, Δh°, and ΔE, according to the ICC, exceeded 0.82. The Dahlberg indices for ΔL* and ΔE were 2.18 and 2.98, respectively. For the reliability calculation, the ICCs for the DIA and the spectrophotometer ΔE were 0.91 and 0.94, respectively.

Conclusions: High agreement was obtained between the DIA and spectrophotometer results for the ΔL*, ΔC*, Δh°, and ΔE measurements. Further, the reliability of the measurements for the spectrophotometer was slightly higher than the reliability of all measurements in the DIA.
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July 2016