Showing papers by "Jaafar Abduo published in 2018"

Accuracy of Intraoral Scanners: A Systematic Review of Influencing Factors.

Abstract: Digital impressions by intraoral scanning (IOS) have become an increasingly popular alternative to conventional impressions. This systematic review aimed to evaluate the accuracy of the available IOS systems for dental impression, and identify the influencing factors on accuracy. The literature search was completed to retrieve all the studies that investigated the IOS accuracy when used to scan teeth. A total of 2305 studies were initially obtained. After applying the inclusion criteria, 32 studies were suitable for the analysis. The following systems were included in the review: Cerec Bluecam, Cerec Omnicam, Cadent iTero, Lava C.O.S, Lava True Definition, TRIOS, TRIOS Color, E4D, Planscan, MHT, Carestream 3500 and Zfx IntraScan. In comparison to conventional impressions, the IOS systems can be reliably used for diagnostic purposes and short-span scanning. However, for whole arch scanning, the IOS is susceptible for more deviation. The studies indicated variable outcome of the different IOS systems. While the accuracy of IOS systems appears to be promising and comparable to conventional methods, they are still vulnerable to inaccuracies. For prosthesis fabrication, the IOS accuracy is enhanced by reducing the span of scanning, and ensuring the scanned surfaces exhibit minimal irregularities.

Longevity of ceramic onlays: A systematic review.

Abstract: OBJECTIVE: This systematic review aimed to evaluate the longevity of ceramic onlays and identify the factors that influence their survival. MATERIALS AND METHODS: An electronic search was conducted through PubMed (MEDLINE), Google Scholar and Cochrane Library, up to August 2017. The literature search aimed to retrieve all the clinical studies on the longevity of ceramic onlays. Ceramic onlay was defined as any partial ceramic restoration that covers at least one cusp. RESULTS: A total of 21 studies met the selection criteria and were deemed suitable for this review. The medium‐term studies (2–5 years) indicated a survival rate of 91‐100%, and the long term studies (more than 5 years) showed a survival rate of 71–98.5%. The most common reason of failure was fracture, followed by debonding and caries. The most common patterns of deterioration were loss of margin integrity and discoloration. Onlay longevity can be enhanced if the preparation allows for at least 2 mm occlusal ceramic thickness and incorporates additional retentive features. Restoring teeth that are nonvital, teeth in a more posterior region, or teeth for patients with parafunctional habits appears to be associated with greater ceramic failure. Fabrication materials and methods, and adhesive bonding system did not seem to influence onlay longevity. CONCLUSIONS: The clinical performance of the ceramic onlay appears acceptable regardless of the follow‐up duration. Fracture of the ceramic onlay is the predominant cause of failure, and the most observed form of deterioration was associated with the restoration margin. CLINICAL SIGNIFICANCE: Ceramic onlay appears to be a reliable option to restore posterior teeth. The most common pattern of failure is fracture of the ceramic material. The risk of ceramic onlay failure seems to increase if the restored tooth is nonvital and the patient demonstrates parafunctional habits.

Influence of novel implant selective laser melting framework design on mechanical durability of acrylic veneer.

Abstract: BACKGROUND A novel implant framework design is proposed to improve the mechanical durability of acrylic veneer. PURPOSES Comparing the mechanical durability of acrylic veneer on implant frameworks fabricated from selective laser melting (SLM) with novel design against conventional computer numeric controlled (CNC) milled frameworks. MATERIALS AND METHODS Implant titanium frameworks with distal cantilever were fabricated by SLM (n = 10) and CNC milling (n = 10). The CNC frameworks had multiple vertical pins, while the SLM frameworks had 3D metal networks of horizontal beams connected by vertical struts. All the frameworks were veneered with acrylic teeth and resin material and were subjected to a static load-to-failure test at the cantilever region. The load-to-failure readings and the pattern of prosthesis damage were recorded for each prosthesis. RESULTS The CNC and SLM prostheses failed at statistically similar loads. The acrylic veneer around the CNC frameworks tend to initially crack around the distal implant followed by acrylic chipping. Six SLM prostheses failed at the framework connector on the mesial implant by separation of the screw seat. After reloading these prostheses, they failed by acrylic veneer chipping. The SLM prostheses had significantly less incidence of acrylic flexure and severity of acrylic veneer chipping than CNC prostheses. CONCLUSIONS The SLM framework with novel design is efficient in reinforcing acrylic veneering. However, the SLM frameworks appeared weak in thin sections, such as the screw seat.