CS2-9. Communication with Dental Laboratory and Infection - Assist. Prof. Dr. Delal Bozyel - 07.03.23 - 09_00.pdf

COMMUNICATION WITH DENTAL LAB AND ENFECTION Learning Outcomes: After the completion of this subject, student will be able to: 1. Explains the correct information about the treatment process to the dental laboratory 2. Provides accurate disinfection according to the properties of the material. Unlik...

COMMUNICATION WITH DENTAL LAB AND ENFECTION Learning Outcomes: After the completion of this subject, student will be able to: 1. Explains the correct information about the treatment process to the dental laboratory 2. Provides accurate disinfection according to the properties of the material. Unlike other dentistry departments, the Prosthetic Dentistry department is not just about the dentist; it has treatment stages in which the technician also plays an important role. The responsibility of the dental laboratory is to prepare a prosthesis according to the specific instructions given by the dentist. Dental laboratories are responsible for preparing the desired prosthesis, supported by communication through the form and materials sent to them by the dentist. In addition, they should have the knowledge and skills to observe possible situations in treatment from their own perspective. The dentist also has the knowledge and authority to delegate laboratory procedures to technicians according to the patient's functional and aesthetic needs. 1. The Importance of the Dental Laboratory The dental laboratory technicians are important members of the dental health team. The interaction between dentists and dental laboratory technicians has been termed a ‘‘love- hate relationship’’, and the laboratory work authorization has been called the most frequently used and abused form of communication between them. Dentists and dental technicians are a team in ensuring proper prosthetic design, and each team member must support the other to continually improve professional services. The ultimate challenge is not perfection, but the pursuit of excellence for patients despite their financial resources. When necessary, dental technicians do not only do the desired job; They must be capable of noticing situations that require control such as deficiencies or wrongs in the desired job and they must be accessible at any time. Therefore, it is the dentist's responsibility to establish correct and respectful communication with the appropriate laboratory and experienced technician. 2. What the Technicians Expect from the Dentists Materdomini stated that “communication is the key to success in cosmetic dentistry/laboratory relations.”. Verbal communication is traditionally unreliable. Instructions for the work assigned to the dental laboratory technician should be clear. A comprehensive dental laboratory form with a necessary checklist is an essential element for dentist-technician communication. The form describes required components of restorations with illustrations and allows for additional information that the dentist feels is necessary for each individual situation (Pic-1). In a study (Barbara et al., 2005), dental technicians' complaints about dentists were evaluated. Common problems rcportcd by respondent technicians included inadequate occlusal reduction for crown prcparations (47%), poor impressions (40%),and the abscncc of rest preparation for removable partial dentures (20%). Dentists have a great role to play in eliminating these problems. 3. Information to be Given by the Dentists The factors that a dentist should pay attention to when sending a fixed prosthesis job to the technician are tooth preparation, impression material, impression method, planning (material selection, body type), color, aesthetics, occlusal records, information about the implant used, if available, and disinfection of the impressions taken. In addition, there should be an information sheet containing more detailed information about the work to be done. It should be written in this paper: 1. The patient’s name, gender, age 2. The date when materials taken by patient 3. If is is necessary patient’ s photos, videos 4. The patient’s expectations 5. The type of occlusion 6. Dentist’ s name, sign, phone number and referance number Necessary information in fixed crown/bridge treatment: Framework type, occlusal surface, type of occlusion, pontic design and margin design are are strategic directions for the dental technician. · Preparation: Preparations carefully prepared with margins that are regular and definitive, have axial surfaces in harmony with parallelism when necessary, and have surfaces and contours that are smooth, nicely finished, and devoid of undercuts make it possible for the dentist to obtain accurate impressions and for the technician to work precisely. One of the greatest difficulties experienced by the dental laboratory technician is the fabrication of restorations for teeth that have been insufficiently reduced, particularly for veneer crowns. Occlusal surfaces should be reduced sufficiently to allow space for producing a harmonious occlusal pattern. Axial surfaces on teeth prepared for veneer crowns should be reduced to permit the fabrication of esthetic veneers with an adequate bulk of veneering material to develop lifelike colors, without exceeding the bounds of normal tooth morphology, and where recessed seats and internal attachments are required, the preparation should be reduced to permit their proper placement. All of this reduction of the tooth must be done and, at the same time, the demands of pulp preservation and good operative procedure must be met. The laboratory technician must realize that the preservation of the ‘vitality of the tooth is paramount. If tooth reduction must be limited, both the dentist and the technician must use all of the care, skill, and artistry that they have at their command to preserve the pulp and still produce a clinically and esthetically acceptable restoration. · Occlusal Recording: The next responsibility of the dentist in the construction of a fixed partial denture is to make registrations of maxillomandibular relations so that the casts can be oriented in the articulator. The dentist must select the method or technique that is suitable, and provide the laboratory technician with accurate usable registrations. If a simple hinge articulator is to be used, an accurate interocclusal record of centric relation is necessary. If adjustable articulators are to be used, the registration should be as sophisticated as the capabilities of the articulator and the dentist permit. The more complicated the articulator and registrations used, the greater is the responsibility of the dentist in personally transferring these registrations to the articulator and in setting and adjusting it. In occlusal recordings taken by biting wax or silicone, it should be ensured that the wax is removed from the mouth at the right time, and if necessary, bite recordings should be taken several times to find the correct closure. It is important for the technician to apply the correct procedure, especially in full mouth cuts or in patients with different bites, to take the bite record before and after tooth cutting. · Impression: The most important key in the impression stage is the dentist's selection of the right impression method and material. In the impression taken, it should be ensured that the collar regions, preparation borders, walls and proximal regions are clear. Since any space will cause large air bubbles, the area to be measured should be well dried and the measure should be mixed well. It should be ensured that the marginal limits are well followed, and impression methods should be changed when necessary. Otherwise, prosthesis-gingival mismatch will occur. Retraction for this will provide a healthier result. If it is to be prepared temporarily, bleeding should be provided before the measure to be taken with alginate. It is necessary to measure both jaws with the necessary impression material in order to see the closure. According to the dimensional stability ability of the impression material, it should be delivered to the technician at the right time. The dimensional stability of impression materials is a key factor for the accuracy of final dentures. There may often be a delay between taking the impression and arriving at the laboratory where the model was poured. It is important that the impression material does not shrink, expand or deteriorate during this time. Although there are a limited number of studies on polyvinylsiloxanether, researchers have reported that this impression material will be a good alternative for dimensional stability (Memişoğlu, 2019). The main causes of dimensional shrinkage in elastomeric impression materials are; loss of volatile components during polymerization, water loss and insufficient elastic recovery. The continuous evaporation of volatile substances from the polymerized elastomeric impression material explains why long residence times affect the possible increase in impression size. A study has shown that conventional impression materials all contract from the occlusal face, while expanding from the axial walls, especially near the collar regions. These shrinkage and expansion amounts indicate the general deformation and deviation from the main model. For this reason, it is the physician's great responsibility to deliver the measure to the technician at the right time. ● Choosing Colour: In addition to using various methods such as photography and video shooting, choosing colors with correct and appropriate light and color scale suitable for the brands that the technician works with eliminates errors that may occur especially in aesthetic areas. Using color scales with more than one color tone will facilitate the work of the physician and technician. While the color can be taken at the framework stage in metal-based prostheses, the color must be taken in the first session in order to choose the color of the infrastructure in porcelain-based prostheses. ● Material Selection: Depending on the financial possibilities of the patient, the physician must choose the type of infrastructure and the right material for the superstructure and convey this information to the technician in writing. ● Pontic Design: Pontic selection should be made depending on the patient's bone and gingival health and oral hygiene control, and written information should be given for the technician to produce a body suitable for this selection. ● Finishing: Cementation and finishing of a fixed prosthesis ready for cementation is a laboratory procedure of great importance and the dentist is responsible for its proper completion. Marginal fit, contours and primary contact areas should be checked intraorally by the dentist and problems should be eliminated before the glazing phase. The dentist is responsible for all these details, and if he delegates their performance to the laboratory technician, she/he must inform the technician of his/her requirements and guidelines and review the work to ensure its accuracy and perfection. Documentation Communication Through Digital Technology: Digital dentistry offers the opportunity to collect and classify personal patient records, 3D digital impressions and restoration designs thanks to different computer programs. Thus, it has been possible to digitally record patients' demographic records (clinical measurements, analyses, color data, intraoral photographs, scans, tomography and x-rays) together with their treatments. By using digital technology, the treatment offered to the patient at the beginning with dynamic documentation is to be carried to the final in a similar way. In particular, the smile design is prepared according to the diagnosis models taken by the technician. The technician prepares wax-up models with the guidance of the dentist and from his own perspective. In general, the information given is insufficient for the technician to fully use his abilities. Today, thanks to advanced 3D design programs; By providing calibration between intraoral scans and photographs, a design is made, a 3D model is produced and the design is transferred to the mouth with a mock-up (Uslu and Aykor, 2020). A successful smile design evaluates the treatment in 4 dimensions as aesthetics, function, structure and biology. The design is transferred from the face to the mouth, then to the model, and finally to the mouth with restoration, with the arrangements made in 4 main aspects: the horizontal plane line, the midline of the face, the tooth shapes and the color. The advantage of the DSD protocol is that it enables to make these transfers in a shorter time in the most ideal way. With better communication, the patient's personal preferences and/or morphopsychological characteristics are transferred to the technician and near-perfect restorations can be obtained (Coachman, 2012). Points to Consider in Fixed Implant Prostheses: Due to the tooth loss, preferability of fixed porstheses for most of the patients, insufficient performances of removable dentures, psychological effects of teeth loss and desires of the old-aged “baby-boomers” generation, predictable long term success of implant supported prostheses, advantages of the implant supported restorations and increased awareness and conciousness of the society increased the ratio of implant choice for treatment. Similarity between fixed implant prostheses and tooth supported fixed prostheses during the construction phase is present whereas the main difference arise from the tolarance to the upper prosthetic structure. Rather than natural tooth, osteointegrated implants does not have the periodontal ligaments and they have slight mobility only from the elasticity of bone structure. Because of that impression technique and sensitivty plays important role for reflecting the correct and exact location of the implants on the 3-D main study model, this phase of construction is so vital for implat supported prostheses. The closer the position of the implants in the bone and the position in the impression model obtained are, the more passive the prosthetic superstructure provides. Passive fit is defined as the state of full adaptation to abutments without applying tensile, compressive and bending forces when implant-supported prostheses are not under the influence of occlusal forces. One of the most important stages to achieve passive compliance is the impression stage. Factors affecting passive fit can be listed as are the number of implants, implant localization, impression material used, type of restoration (cemented / screwed), type of abutment used (straight / angled), design and configuration of the metal substructure, substructure material (nickel-chrome / titanium / zirconium),the design of the prosthetic restoration (one-piece/multi-piece), the experience of the technician at the laboratory stage and the problems to be encountered during the labaratory phase. Marginal mismatches that are invisible to the naked eye or not detectable by dental instruments are considered clinically acceptable. Marginal openings between 100 and 150 μm were considered clinically acceptable in studies. Thanks to the use of an intraoral scanner, there is no need to obtain a plaster model; The impressions quality can be easily evaluated by both the physician and the technician, and some or all of the scanning can be easily renewed as soon as an error is detected. Thus, the communication between the laboratory and the physician is strengthened. At the same time, since the impresions can be stored in digital environment; There will be no problem of space due to the storage of plaster models, and the dimensions can be stored for a long time without being damaged. By not using spoons, splint materials, impression materials and plasters, both the cost of these materials can be saved, and the impressions can be sent to the laboratory instantly in electronic environment, thus speeding up the treatment. Recently, the American Dental Association has published updated guidelines to improve the relationship between dentist and laboratory technician. These guidelines not only improve communication between the laboratory and the dentist, but also improve the effectiveness and quality of care for the patient (American Dental Association: Statement of Prosthetic Care and Dental Laboratories. 2000, pp. 455). In addition to all these factors, another important responsibility of the physician towards the technician is that the materials sent to the laboratory are in appropriate storage conditions and disinfected. The entry and establishment of a microorganism in the host is called an infection, and the resulting disease is called an infectious disease. Microorganisms that settle in the host can also infect other living things in various ways. Sources of infection in dentistry are hands, saliva, blood, blood clots, liquid droplets, instruments and devices used in dentistry. The transmission of pathogenic microorganisms from one person to another is called cross-contamination, and the infection that occurs in this way is called cross-infection. Sources of infection in dentistry are hands, saliva, blood, clots, liquid droplets, instruments and devices used in dentistry. During dental procedures, the patient's mucous membrane and gums may be damaged, as a result, saliva and blood can easily enter the impression material during the impression taking process. Bacteria and viruses contaminate the impression material. Dental impression materials, whose dimensional stability and precision are improving day by day, are a potential source of cross-infection, although they have effective antibacterial properties, and therefore they can pose a risk in terms of health. Microorganisms on the surface of the plaster model obtained from the impression spread to the model (Kotsiomiti et al., 2008), so that the infected model is transferred to the dental laboratory and may pose a danger to dental technicians working remotely. During the work of dental technicians, gypsum dust from infected models enters the respiratory tract, settles on clothing and environmental surfaces and remains alive for a considerable time. For example, the tuberculosis pathogen Mycobacterium tuberculiosis remains dangerous for several weeks. At the same time, pathogenic agents can be transmitted not only by impressions, but also by means of prosthetic parts used in the patient's mouth and not disinfected afterwards. Therefore, reverse migration of pathogens from the dental laboratory to the dentist's office is also possible. In order to carry out infection control in dentistry, as a basic principle, every patient should be considered as a potential infection and precautions should be taken without any discrimination. For this purpose, sterilization and disinfection, which are the most important stages of infection control, should be applied well. The devices and surfaces used should be purified from organic matter and pathogens before disinfection and sterilization processes. This process is called decontamination Materials Used in Decontamination: • Special brushes, soft cloth, sponge • Ultrasonic washing device • Washing/disinfector devices • Tool dryers • Detergent-disinfectant/enzymatic solutions. Sterilization: It is the destruction of all microorganisms, including viruses, bacteria, fungi and spores. Disinfection: It is the process of destroying microorganisms (except bacterial spores) on inanimate substances and surfaces or stopping their reproduction. Disinfectants can be classified as low risk, medium risk and high risk groups according to the risk of infection. Disinfectants in the high risk group are used in dentistry. In order to prevent cross-contamination in prosthetic procedures, methods such as adding disinfectant to alginate powder, nanotechnology, and adding disinfectant to gypsum powder have been suggested among alternative impression disinfection methods. Disinfection solutions used in dentistry; combined synthetic phenol compounds are iodophor, glutaraldehyde, sodium hypochlorite, 0.25% benzalkonium chloride, isopropyl alcohol, ethyl alcohol, chlorhexidine. Factors determining the effectiveness of disinfectants: •The structure of the disinfectant •Concentration •Application method •Application time. Sterilization methods are; sterilization of the dimensions with UV (Ultraviolet) rays, direct current discharge, steam autoclave, ethylene oxide gas autoclave, argon radio frequency discharge and microwave sterilization. Disinfection of impression materials and prostheses is done in seven stages; 1. All dentures removed from the mouth should be washed under running water and cleaned and disinfected with an ultrasonic cleaner. 2. All impressions should be disinfected after rinsing with water and then plaster models should be obtained. 3. Pumice should be discarded after use. 4. Burs should be changed after each use and stored in disinfectant. 5. Protective measures should be taken against splashing contaminated water during operation and air filters should be used to prevent airborne contamination. 6. Attention should be paid to the cleaning and disinfection of contaminated laboratory areas. 7. Disposable aprons should be worn on the patient during the impression and prosthesis production processes so that the clothes worn by the patient are not contaminated. Chemical Disinfectants Used in Dental Impressions: Chemical disinfection is the method frequently used in the disinfection of impressions. Glutaraldehyde: It is an effective agent against a wide range of microorganisms, including viruses. When dissolved in water, a slightly acidic solution is obtained. They are generally available in the market as a 25% solution. The 2% concentrations used in the application are classified as highly disinfectant. They are buffered with a basic substance, as they show maximum effectiveness at a pH of 8.5. It is sporicidal in basic character. While sterilization is provided in 6-10 hours, disinfection is provided in less time. While it acts on bacteria, fungi and viruses including M. tuberculosis within 10-20 minutes, it kills spores in 10 hours. Concentrations of 0.25% - 0.50% are used for surface disinfection. It should be used in well ventilated environments. Contact with skin should be avoided. It is toxic. Iodophors: They are excellent cleaners and good disinfectants. These iodine-containing compounds release free ions and disinfection is achieved by utilizing the antiseptic property of iodine. While they have bactericidal, tuberculocidal, virucidal and fungicidal effects, they do not affect spores. It is used by diluting 1:100 or 1:1000. Moderate disinfection is achieved with a bath of 10-30 minutes. The disadvantage is its smell and staining of the texture. Sodium hypochlorite: Its solutions are transparent, slightly green - yellow in color. They show a strong alkaline reaction. Despite its broad spectrum bactericidal activity, it has a corrosive effect on metal surfaces. They decompose in the light, so their solutions must be prepared fresh. They are generally found in the market at a concentration of 5%, and in practice, mostly 1% solutions are used. It is one of the most effective substances in disinfection. Hexachlorophene: Alcohol and alkali solutions are used to dissolve this substance, which is in the form of white crystals. While they are effective on S. aureus and gr (+) bacteria, they do not affect gr (-) bacteria. In practice, 1% solutions are used. Benzalkonium chloride: They are yellowish white amorphous substances soluble in water and alcohol. Concentrations of at least 0.1% are effective against sporeless microorganisms, except for M. tuberculosis. Chemical disinfectants can be applied in 2 different ways; by dipping the impression or by spraying the impression. Immersion disinfection ensures that all surfaces of the dental impression are exposed to the disinfectant, but hydrocolloids and polyether materials cannot be immersed in disinfectants due to the absorption phenomenon. The spray disinfection method reduces the possibility of degradation, especially in hydrocolloids and polyether, and also uses less disinfectant solution but may not reach the abrasive areas. It has been reported that hydrocolloid impression materials carry 2 to 5 times more microorganisms than elastomers. During the disinfection process, the impression material should not lose its dimensional stability, accuracy and critical surface properties. Due to their hydrophilic properties, it has been reported that hydrocolloid impression materials undergo more dimensional distortion during the disinfection process. For this reason, it is recommended to disinfect alginate, which is one of the hydrocolloid impression materials, by spraying, not by dipping. However, it was thought that disinfection would not be achieved with the desired effectiveness, since spray disinfectants accumulated in the ragged areas of traditional impressions and could not contact the entire impression surface homogeneously with the disinfectant. For this reason, care should be taken to apply the spray so that the excess disinfectant flows from the surface and to ensure an equal amount of wetting of the spray disinfectant applied to the impression surface. In order to provide effective disinfection, the American Dental Association (ADA) recommends that the alginate impression material is placed in a closed bag and kept there for the required disinfection period in spray disinfection. Vinyl polysiloxane impression materials (VPS), from the group of elastomeric impression materials, are widely used due to their superior elastic properties, excellent dimensional stability and high accuracy. However, they are hydrophobic due to their chemical structure. To overcome this feature, manufacturers have added surfactants to these materials and classified them as hydrophilic VPS impression materials. Included surfactants increase water absorption when immersed in disinfecting solutions. Prolonged immersion of hydrophilic polyvinyl siloxane in disinfecting solution should be avoided. Leaving the material in the disinfectant solution for longer than the recommended immersion time may reduce the dimensional stability of the material as a result of the additional ingredients included in the formulation. In a study investigating the disinfection of polyvinyl siloxane and polyether impression materials, it was shown that adequate disinfection was provided in impression materials applied disinfectant for 10 minutes by spray or dipping method, and there was no bacterial growth in plaster models obtained from these impressions. In addition, it has been stated that Sars-Cov-2 virus, which has caused pandemics in recent years, is sensitive to disinfectants containing 75% ethanol and chlorine due to its oily bilayer structure. In a study examining the effectiveness of disinfectant materials used in dentistry on microorganisms on the surface of silicone, irreversible hydrocolloid and zinc oxide impression materials, it was determined that there was almost no microorganism growth after 3 and 10 minutes of disinfection with iodine-based disinfectant solution (betadine). and at the end of 10-minute disinfection, only growth was observed on the surface of the zinc oxide impression material contaminated with C. albicans, and they also reported that complete disinfection was achieved at the end of 3 and 10 minutes disinfection with glutaraldehyde. It is also recommended to wait for 3-10 minutes with hydrocolloid impression materials with 1% sodium hypochlorite or 0.05% iodoform, 2% glutaraldehyde. When the impression materials are disinfected using 0.2% chlorhexidine gluconate, 1.0% sodium hypochlorite and 2.2% glutaraldehyde, sodium hypochlorite has been shown to cause the dimensional change at the lowest level. Among impression materials, alginate and zinc oxide eugenol materials showed more dimensional changes than other additive type silicone and condensation type silicone materials. Consulting with the manufacturer of the impression material before the procedure is beneficial in determining the method to be applied. Zinc oxide eugenol impression materials are disinfected with disinfectants that do not contain chlorine compounds. Since polyether impression materials are hydrophilic, they are kept in sodium hypochlorite for 2-3 minutes or disinfected with a spray in order not to impair their dimensional stability. It is equally important not to rely solely on the short-term and weak disinfecting effect of ethyl alcohol or hydrogen peroxide. The impression should be washed under water, even at this stage, cleaning can be done more effectively with the help of a brush and detergent. This cleaning and washing process is effective in reducing the amount of microbial accumulation and organic residue in the measure. The idea of disinfection of dental impression materials using UV (Ultraviolet) rays has emerged as an alternative due to the negative effects of chemical disinfectants on the materials. When microorganisms are exposed to ultraviolet rays of a certain wavelength (200-280 nm), their ability to reproduce is destroyed and inactivation occurs faster, so they no longer pose a threat to humans. Ultraviolet light with a wavelength of 200-280 nm is lethal to bacteria, bacterial spores, viruses, mold, mold spores, yeast and algae. Since ultraviolet light has a low penetrating power, it is not easily absorbed by organic materials. Before ultraviolet light disinfection, visibly soiled surfaces must be cleaned. The wavelength used when using the dental ultraviolet room is 254 nm, which has been reported to be very effective in disinfecting the impressions. Exposure of humans to ultraviolet light is harmful and can cause eye damage and burns. Therefore, controlled use of Ultraviolet-C disinfection is required. In a survey study conducted in England in 2010, the impression disinfection protocols of dentists and dental technicians were evaluated. It was stated that 37.2% of the dentists washed the impressions with water before disinfection, and 2.6% of them removed the debris with the help of a brush. It has been reported that 50% of dental technicians disinfect the impressions regardless of the disinfection status of the impressions that come to the laboratory. It was reported that 95% of dental technicians received impressions contaminated with blood. Failure to comply with infection control protocols endanger dental practice and laboratory staff and people who are susceptible to infections. The British Dental Association and the American Dental Association stated that accepting each patient as a potential carrier of infection is the only safe approach in routine treatment and that all impressions and prostheses should be chemically disinfected. Wax stencils and wax bite recordings can be disinfected with the spray method using iodophor. For disinfection of tuberculosis bacillus, wax stencils should remain wet with disinfectant for the recommended time. After it is wiped and sprayed for the second time, it should be stored in a sealed plastic bag for the time recommended by the manufacturer. After disinfection, these materials should be washed again. Chemical disinfectants and autoclaves can be used for the disinfection of fixed prostheses. In an in vitro study examining the efficacy of chemical disinfectants on crowns, 1% and 2% sodium hypochlorite and 2% alkaline glutaraldehyde were reported to provide high-level disinfection in five, ten, and fifteen minutes. Studies have shown that disinfection solutions cause changes in the surface properties of prostheses. The surface roughness and surface hardness of the ceramic play an important role in the initial plaque adhesion. Therefore, disinfection processes applied in the infection control procedure should not affect the surface properties of the prostheses. In their studies examining the surface roughness of ceramics, it was reported that the sterilization and disinfection process with 2% glutaraldehyde or the sterilization process with autoclave did not cause a change in the surface roughness. Aesthetics has become an important factor in the success of dental restorations, and in order to achieve a good color match with these restorations, they must exhibit similar optical properties to natural teeth. From this point of view, the disinfection procedure to be applied for infection control should not affect the optical properties of the restorations. According to the study conducted by Ma et al. examining the characteristic surface properties and color of fixed crown materials of chemical disinfectants, it has been reported that while different chemical disinfectants do not affect the surface properties of dicor and feldspathic porcelains, they cause changes in optical properties. However, these color changes are not visible. Disinfection processes should also be carried out on plaster models, which are another cross-infection factor. ADA and CDC recommended disinfection of dental plaster models by spraying or keeping them in a disinfectant solution. It has also been noted that reusable metal measuring spoons in the traditional analog workflow must be perfectly cleaned of residue. They stated that the residues in the measuring trays should be removed beforehand, since the mechanical operation by ultrasonic devices cannot remove the residues on the measuring trays and will impair disinfection and sterilization. During the taking of digital impressions, the scanner tip can be contaminated with saliva and droplets. The disinfection and sterilization protocols of the scanner tips mostly depend on the recommendations of the manufacturers. Alcohol-based disinfectants prevent scanner tip damage and can generally be applied during the disinfection process. Impression Disinfection Agent Disinfection time Alginate Iodophors and 5.25% sodium hypoclorite Polyether İodophors and sodium hypochlorite, complex phenols 10 minutes Polisulfite İodophors and sodium hypochlorite, complex phenols 10 minutes Silicon İodophors and sodium hypochlorite, complex phenols 10 minutes Agar İodophors and sodium hypochlorite Zinc oxide eugenol İodophors 10 minutes 10 minutes 10 minutes Dentistry in the Covid-19 Pandemic Expression of ACE2 in minor salivary glands is higher than in lungs, suggesting that salivary glands may be potential targets for Covid-19. Covid-19 disease is transmitted mainly through droplets. The detection of viruses in the respiratory tract of infected people who do not show symptoms shows that these people can also be contagious. In addition, it has not yet been reported whether patients in recovery are potentially a source of transmission. The mean time to detect viral RNA from the samples was determined as 24 days for the shortest and 42 days for the longest (Liu et al., 2020). In addition to being in close contact with the patients during the treatment, dentists are also in contact with the saliva and blood scattered around with the production of too much aerosol. Due to these factors, dentists are at a higher risk of encountering Covid-19 than other healthcare professionals. In addition, dental clinics can become a source of infection if necessary infection control measures are not taken. As a result, no decisions regarding diagnosis or treatment planning should be left to the discretion of the technician, specifically with regard to laboratory work. This is the dentist's responsibility and obligation to his patient and should not be transferred knowingly or negligently. Only a dentist is familiar with the total problems of the mouth and their relationship to the patient's systemic health. However, the dentist is also responsible for providing accurate, necessary and complete information to the laboratory and ensuring infection control of the materials delivered to the technician. REFERANCE: Leeper, S. H. (1979). Dentist and laboratory: a" love-hate" relationship. Dental Clinics of North America, 23(1), 87-99. Materdomini, D. (1994). Communicate visually with your laboratory. J Am Acad Cosmet Dent, 1, 32-34. Maxson, B. B., & Nimmo, A. (1997). Quality assurance for the laboratory aspects of prosthodontic treatment. Journal of Prosthodontics, 6(3), 204-209. Memişoğlu, G. (2019). Protetik diş tedavisinde kullanılan çeşitli ölçü maddelerinin boyutsal değişiminin dijital ortamda değerlendirilmesi. Şeşen Uslu Y, Aykor AA. 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