With advancements in computer-aided design and computer-aided manufacturing (CAD-CAM) technology(, Ortorp etal.,2011, Koutsoukis, etal.,2015)the application of intraoral scanners (IOSs) in dentistry has become popular. Hence, the use of IOSs has been researched as an alternative to traditional impression making methods.( Ting-Shu etal.,2015,Alghazzawi etal.,2016 )
Unlike conventional methods, a physical impression or a gypsum cast is not required when IOSs are used for digital scans, the first step in the digital workflow, reducing the possibility of cross-infection, cost, and time(Rodiger etal.,2017, Yun etal.,2017)Since the outcomes of digital scans are directly viewed on the monitor, immediate remaking of the scan is possible upon encountering a problem, and the procedure is less sensitive to the technical skill of a dentist. (Alghazzawietal .,2016, Joda etal.,2016 ) Furthermore, the digital workflow facilitates communication and cross-collaboration with dental laboratory technicians.(Nedelcu, etal.,2014,Pagano etal.,2019)
Optical IOS types include confocal microscopy and triangulation (Huang etal.,2015) A confocal microscopy-based scanner uses a light source amplified by stimulated emission of radiation. The optical detector only detects the in-focus light through a pinhole from the light reflected on the tooth surface and digitizes it into images. IOSs using this technology include iTero (Align Technology, Inc), 3D Progress (MHT), and TRIOS (3Shape A/S). Triangulation is a noncontact technology that collects the shape data of an object to create a 3-dimensional (3D) cast( Peiravi, etal.,2010) and can be divided into passive and active triangulation. In passive triangulation, light is not directly released from the scanner, and only the reflected surrounding light is detected. However, in active triangulation, the scanner directly projects light onto an object and collects the reflected light to compute the target object's position. (Logozzoetal.,2014)IOSs using active triangulation technology include the CEREC Omnicam (Dentsply Sirona), CS3600 (Carestream Dental), and i500 (Medit Corp).
If the scanned object is flat the receptor will register perfectly straight lines. If something is obstructing the lines the receptor will register deformed lines, thus making it possible to calculate the line deviationsresulting in a surface topology[Ireland etal.,2008]. Triangulation is not possible to conduct if the area being digitized is invisible to both, or either, the laser or the receptor(Logozzo etal.,2014). All these techniques are based on reflections from the surface of what is being scanned. For intraoral use there are many challenging surfaces such as blood, saliva, metals, composite surfaces, enamel, dentine, soft tissue and different light conditions depending on operator unit and office light[Tapie, L., et al.,2015]. Other Obstacles for IOS according to Gimenez-Gonzalez B et al. (2017), stitching errors build up in the program proportionate to the scan distance. These also lead to an improper prosthesis in the end., Third, it can be challenging to see the prepared teeth's deep margin lines. In the case of bleeding, particularly in aesthetic areas where it is crucial for the clinician to place the prosthetic margins subgingivally, it may be more difficult for the light to correctly detect the entire finishing line because light cannot physically detach the gum and therefore cannot register "non-visible" areas, unlike the conventional impression materials. Similar issues may also arise in the event of bleeding, as blood may obscure the prosthetic margins. This is one of the most common problems with IOS and optical impressions. Fourthly, The requirement to pay a charge in order to unlock STL files, or the inability to discard them freely, however Scanning strategies such as scanning path, environment control, and application of scanning-aid agents are used to obtain accurate scanned images (Richert R etal., 2017, Oh HS etal., 2021).
According to some authors, liquid-type coating agents can provide a more uniform coating thickness and an accurate scanned picture than powder-type agents (Oh HS, et al., 2020). This is because variable applications, distances, and timings of the powder-type agents' application on the abutments lead to diverse results. However, fewer studies dealt with the effect of liquid type on fitness accuracy in single-crown. The purpose of this study is to evaluate the internal fit of zirconia crowns supported by implant abutment(metal abutment ) using different scanning aid agents(powder spray Vita,liquid paint Sinbrio, scan body).
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Fitness evaluation for crowns
Tatkin4
dmr.697
Brandon the Cool
LeDogge2020
Nikki1256
Jus8586
131515195
Senteria
