Introduction Dental practitioners have for a long time been innovation focused with the rapid and increasing development of technology in various areas in the modern era

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Introduction
Dental practitioners have for a long time been innovation focused with the rapid and increasing development of technology in various areas in the modern era. Dentistry is one of the areas that has evolved in technology and has begun to use automatic devices such as CAD CAM. Susic (2017) defined CAD CAM as Computer aided Design and Computer aided Manufacturing (CAD CAM) machines. According to Susic (2017), most dental clinics and companies are now using CAD/CAM techniques, in the form of production centers, in the dental laboratory or either in the dental practice. Many advantages related with CAD/CAM gave birth to new dental restorations: the entrance to new, an increase in the reproducibility, quality and increase in the efficiency. Due to the continuous development of computer software and hardware, new strategies for creation and new treatment ideas which will allow an extra decrease in costs. In future, dentists who will be using this technique, need to have basic knowledge about it and must have adequate knowledge to carry out these procedures. As this technology is still under development, there will certainly be disadvantages, where a brief explanation of this invention will be discussed in this essay.
History
In the 1970s, the first utilization of CAD CAM innovation was started and described by Duret and Preston (Duret and Preston, 1991). In this early system, However, several institutions that owned the device have reported an improvement in quality and quantity. There are also the problems of acryl for the formulations that cause allergy in the patients and has been replaced with a block of gold (Blackwell et al., 2017). In 1980, nickel-chromium alloys became an alternative to gold compounds (alloys) due to the increase in the cost of gold. However, the mineral sensitivity turned into an issue after which titanium was found because it did not cause any sensitivity (Rudolph, 2017).

Computer aided program in dentistry
According to Blackwell et al. (2017), In the CAD-CAM system, three basic stages are required for all cases to produce the final result, which is called: scanning, designing and milling. Almustafa) 2016) pointed out that the scanning process, it is taken directly, where the doctor brought the scanner, which contains a three-dimensional camera to photograph the teeth to compensate with artificial teeth. After taking the graphical image, the scanner sends it to the system to process the data and convert it to a three-screen image to make the adjustments and choose the appropriate sizes, and then give the order to manufacture to send data to the milling machine, which contains tools that function to form synthetic teeth by adding a block of zircon, which is one of the best materials suitable for oral health. There is also an indirect method which is not through the clinic, but be in the laboratory where the lab technician receives the patient’s impression after that pour it by the stone material to obtain a model that represents exactly the teeth of the patient then the technician can scan the model with the same camera and send it to the system to do the same process for the production of artificial teeth) Almustafa, 2016).

Advantages of using CAD CAM
Dental CAD CAM systems offer points of interest while creating dental rebuilding efforts to be specific. Some of the advantages are:
The final dental restoration quality is improved. The resin filtered, and resin composite materials have verified sufficient wear resistance for the posterior restorations that are usually stress bearing areas, though, they will need at least alike substantial depth as the lithium disilicate restorations for them (Rudolph, 2017). Due to the natural esthetics and strength of the structure, the tooth can be saved with the traditional techniques called porcelain fused to metal. The final restoration that obtained is finer more precisely because of the development of CAD CAM technology. The restorations require very less space and are light in weight. The final restorations produced by a CAD/CAM system are very promising and they look aesthetically pleasing to the patient. These restorations can be used in the load bearing areas, which is the best advantage of the CAD/CAM restoration furthermore can be used in the anterior restorations. The CAD/CAM restorations are best and ideally indicated to the anterior restorations.

Furthermore, the materials that are used in CAD/CAM contain high-strength ceramics and esthetic, Nano ceramics and composite resins, which facilitate finishing and handling. According to Probst et al. (2012), CAD/CAM can be done on chair side Which aims to provide treatment in one visit or fewer visits, numerous supplies are obtainable for chair-side CAD/CAM restorations, which attained longevity and predictability. The efforts of the lab technician and the dentist all are reduced. CAD/CAM helps to restore the lost oral function and maintain the aesthetic. Various of materials are obtainable for chair side CAD/CAM restorations, which achieved predictability and longevity. Miyazaki et al. (2009), note that These materials comprise esthetic and composite resins, Nano ceramics, high-strength ceramics, which support treatment and finishing. For instance, one of the systems that called CEREC which uses special materials for the construction of ceramic restorations, including IPS E.max and IPS Empress where they work effectively and provide strength and longevity. Therefore, it can be said that CAD/CAM restorations has saved the time of dentists.

Moreover, the ability to provide artificial dental coloring at the same time of the visit, which is considered an advantage aimed at CAD CAM technology to provide. Where the dentist chooses the appropriate color that corresponds to the color of the natural teeth in accordance with the blocks of zircon for the manufacture of artificial teeth and installed accurately with the appropriate color of the same visit without any temporary phase. Almustafa (2016) noted that the digital impression is aimed at taking precise models, which are used in the manufacture of artificial teeth using either traditional or CAD CAM technique that require less time. The color is matched usually at the middle third of the tooth by using a shade guide. it can be said that they are aesthetically pleasing. The advantage over here is that the shade guide that is provided are more upgraded and consist of all the shades matches from lighter to darker shade.
Reducing working time and labor is one of the most important features of this technology. With the use of CAD/CAM technique, the time of the dentist and the technician is also reduced. The computerized digital technique helps to process the model; thus, the clinical efficiency is improved and enhanced. CAD/CAM was designed to eliminate most of the human errors, thus saving the time of both the dentist and the lab technician. The accuracy of the final restoration is enhanced. If any correction is encountered, then it can be easily corrected. According to Hadi et al. (2018), The absence of any CAD-CAM component will create barriers in the design-production relationship, especially when the change is forced and sudden, resulting in problems with time, cost and quality. While providing the complete components will solve the problems that occur between design and production and will be reflected positively on the quality of work and control costs and reduce time.
Disadvantages and challenges of using CAD CAM
It utilizes large amount of computer processing power. CAD/CAM is a computerized technique and utilizes much of the electric power. The functionality of the system depends upon the high source of the electric power. The innovative technique of CAD/CAM involves plasma cutting, laser, knife, spark eroding, pinching, turning, drilling and milling. All these processes require CAD software which is very expensive. This software helps to control and regulate automated machinery. It is an adaptable and flexible process, but a very complex technology.
Furthermore, the color of the restoration may not match to tooth color. Staining might be seen on such restorations. According to Blackwell et al. (2017), If the CAD/CAM restoration is not processed well, there are chances that the food might get stuck in the interproximal spaces, thus increasing the capability of any discoloration to the restoration. For this purpose, Gold is a very good restoration material, and it lasts longer than the ceramic restorations. The color stability lack in such restorations. It can be due to the intake of drinks that affect the chemical properties of the restorations and then these restorations are more prone to get dark from normal color. Such factors have been reported to influence the esthetic and mechanical properties of the restoration while in service. The color stability lack in such restorations, so the patients are advised about it usually. But this is one the drawback of these restorations.
Moreover, longevity and quality are a problem for patients using artificial teeth. This might happen in the ceramic restorations, as there are chances that they might chip off. Quinn et al. (2014), noted that They have good strength but not as good as the zirconia material which made by CAD CAM and to avoid such situations, usually zirconia materials are used as they are bio friendly. Ceramic restorations, including metal-ceramics, are at risk to mechanical fracture, especially the fracture of veneering porcelain. Fracture of a metal-ceramic restoration endanger function as well as aesthetics. The ceramic restorations might chip from any side or start to show cracks. Their longevity is compromised when ceramic restorations are used. In dentist world, they advised by used zirconia over ceramic restorations. The patient also finds it disturbing to visit the dentist repeatedly with the same problem. Ceramic restorations do have good show good strength properties, but zirconia is superior over ceramic. (Blackwell, 2017).
On the other hand, there are several challenges facing users of this technology. Most dentists are not willing to learn this new technique and prefer used the old traditional ways. Also, it is a very expensive technology though it is innovative. To use this technology, the dentist must get the require training also needs to buy a software that is very expensive, and it might cost a lot. The maintenance of the system is also demands for a huge responsibility. Moreover, the dentist also requires an engineer for this purpose to take care of the software and all the related systems. furthermore, there some dentist presents who prefer the conventional methods rather than modern one, as they don’t look forward to training themselves.

Conclusion
Presently the CAD/CAM technology is center of attention in dentistry. All prosthodontics utilizing CAD/CAM technology concludes that they are very expensive restorations but with the recent development in the technology, the final milled restoration is tougher and stronger than the previously milled restorations that usually resulted in fractures. The future is expected to be more advanced and technological, the laboratory work and working time of these procedures are greatly reduced. There restorations can be fabricated quickly and their efficiency in strength and fitting has greatly enhanced. There so many advantages of CAD/CAM technique. Like it provides better aesthetic results, improved strength and very durable. It provides a tooth-colored restoration in single visit appointment is the main goal of the chair-side concept with CAD/CAM technology. The CAD/CAM system in-office allows the dentists to provide same-visit restorations that are accurate and esthetically satisfied. The longevity and quality of such restorations might be compromised. Fracture of a metal-ceramic restoration endanger function as well as aesthetics. Ceramic restorations do have good show good strength properties, but zirconia is superior over ceramic that made by CAD CAM. Thus, it is ideally advised by the dentist to use zirconia in stress areas.