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Background: A novel β-coronavirus infection (COVID-19) was first detected in Wuhan city, spreading rapidly to other countries and leading to a pandemic. Dental professionals and patients are exposed to a high risk of COVID-19 infection, particularly in the prosthodontic practice, because of the bio-aerosol produced during teeth preparation with dental handpieces and the strict contact with oral fluids during impression making. This paper aimed to provide an overview to limit the risk of transmission of COVID-19 infections during prosthetic procedures in dental offices. Methods: An electronic search was conducted on the electronic databases of PubMed/Medline, Google Scholar, Embase, Scopus, Dynamed, and Open Grey with the following queries: (COVID-19) AND/OR (SARS-CoV-2) AND/OR (Coronavirus) AND/OR (contaminated surface) AND/OR (cross-infection) AND/OR (Prosthodontics) AND/OR (dental ceramic) AND/OR (glass-ceramic). A manual search was performed as well. Results: From the 1023 collected records, 32 papers were included. Conclusions: Dental offices are at high risk of spreading SARS-CoV-2 infection due to the close contact with patients and continuous exposure to saliva during dental procedures. Therefore, pre-check triages via telephone, decontamination, the disinfection of impressions, the sterilization of scanner tips, and the use of specific personal protective equipment, dental high-speed handpieces with dedicated anti-retraction valves, and effective mouthwashes are strongly recommended.

Aim: The purpose of this survey was to find the attitude and practice of impression disinfection protocol employed by the practicing dentists in their clinical practice in Tamil Nadu. Materials and Methods: Self-administered validated online website based questionnaires were circulated among dentists practicing in Tamil Nadu. The questions were taken up by dentists who were willing to participate in the survey and a total of 200 responses were recorded. There were two sections to the questionnaire: one included demographic information and the other featured questions regarding the disinfection protocol. The responses were recorded in excel sheet followed by statistical analysis of the data. Results: 97.5% of the dentists routinely rinse the impression with running tap water before sending it to the lab/ prior pouring the cast and 2.5% dentists do not rinse the impressions. 78.9% dentists routinely disinfect the working impressions, whereas 21.1% do not disinfect the working impressions before sending it to the laboratory/ before pouring the casts. 48.2% of the dentists stated that they are unsure whether their lab workers disinfect their preliminary/working impression before pouring casts. 46.9% dentists stated that they do not have disinfection guidelines in their clinic. 81.4% believe that covid-19 spreads by saliva and 73.9% dentists have changed the disinfection protocol for impressions after covid-19. Conclusion: It was found that the majority of respondents rinsed and disinfected the impression with running water and disinfected it on a regular basis for 1-10 minutes. This study also indicates a lack of interaction between the dentists and dental technicians about the information on the disinfection status of the impression sent, as well as a need for increased awareness in order to reduce the disease transmission in dental laboratories. Significant number of dentists have changed their disinfection protocol after covid-19 pandemic.

Background Several recent reports have described the development and use of three-dimensional (3D) printed surgical osteotomy guides. However, these methods: are usually costly. Here, we introduce a novel method of manufacturing surgical guides built from inexpensive, easy-to-use, and sterilizable dental impression silicone. Methods Mandibular and fibular models were prepared using a 3D printer for 10 patients undergoing free fibula flap transfer after mandibular resection. During preoperative simulation surgery, Protesil labor, a dental silicone, was molded to the same size as the fibular models to act as surgical guides. Results The authors compared pre- and post-operative bone angles and bone lengths for all cases using simulation surgery models and postoperative 3D computed tomography. Mean bone angle difference was 2.6° and mean bone length difference was 1.7 mm. Cost of the dental silicone was approximately US$5/patient. Conclusions In our series this method allowed the surgeon to perform an accurate osteotomy, inexpensively and time-efficiently.

Purpose: To evaluate the microbial load on impressions and the efficacy of various disinfectants on reducing microorganisms from the impression surface after disinfection. Materials and Methods: A total of 50 dentulous impressions were made for dentate patients each of age 20 to 50 years using Alginate and Polyvinyl siloxane. Impression compound and zinc oxide eugenol were used for edentulous patients each of age 50 to 70 years, total of 50 edentulous impressions were made. Samples were collected with the help of an 8mm diameter sterile cork borer from each individual impression. Alginate, ZOE and impression compound had 100 samples each. Polyvinyl siloxane had 125 samples. Out of 100 samples the first group of the sample was assigned as control (n=25), the second group of samples (n=25) were immersed in 2% Glutaraldehyde, the third group of samples (n=25) were sprayed with Dimenol, the fourth group of samples (n=25) were placed in the ultraviolet light chamber. For polyvinyl siloxane, an additional fifth sample group (n=25) was subjected to microwave radiation of 650W. The viability of microorganisms that can persist after rinsing and disinfecting the impression surface was tested by inoculating in nutrient media. The colony forming units were counted and compared with the control group. The data were documented and statistically analyzed. Results: There was a significant difference in the count among the control group and the disinfectant groups. Microbial load found on control groups was taken as 100%. Alginate samples which were disinfected with 2% Glutaraldehyde, Dimenol spray and UV light showed microbial load 31%, 46%, 44% respectively, Polyvinylsiloxane samples showed microbial load 35%, 53%, 48% and 0% with microwave radiation respectively. Impression compound samples showed 32%, 49%, 49% respectively & Zinc oxide eugenol samples with 2% Gluteraldehyde, dimenol and UV showed a load of 39%, 51%, 51% respectively. Conclusion: 2% Glutaraldehyde showed hig

Introducing a novel approach to overcoming a profound gag reflex and aversion to conventional dental impression procedures when fabricating a removable partial denture. The digital workflow is becoming increasingly popular in the discipline of fixed prosthodontics. Chairside digitization of a patient's dentition is a less invasive and more comfortable procedure in comparison to conventional dental impression techniques. The advantages can be most relevant to patients with a profound gag-reflex. Currently, certain challenges exist with full digitization in the discipline of removable prosthodontics. Combining digital and conventional workflows may serve as an alternative technique to construct removable prostheses for groups who cannot tolerate conventional methods. CPD/Clinical Relevance: Many patient groups may not tolerate conventional dental impression techniques. This method offers a combination of existing techniques as a suitable alternative for this cohort.

OBJECTIVE: This study compares standard commercial bolus material (Superflab) to custom prepared silicone dental impression material (CDIM) and play dough material (PDM) with respect to dosimetric properties and applicability by using ion chamber measurement and calculated dose values. MATERIALS AND METHODS: The CDIM bolus was prepared by mixing dental impression silicone material with enough water to maintain a density of about 1.0 g/cm(3). The prepared bolus material is applied on an RW3 solid phantom by covering 10x10 cm(2) area with 0.5–1 cm thickness. Ion chamber measurements were performed separately with and without bolus material application. The setup was scanned in CT and the same procedure was repeated in the TPS using the scan data, in which the Pencil Beam Convolution dose calculation algorithm was used. To compare the effect of bolus material on tissue, the Superflab bolus and CDIM bolus were applied with 1 cm of thickness on postmastectomy scar and dose calculations on TPS were performed. RESULTS: After comparison of the dosimetric values for Superflab, CDIM and PDM, we obtained statistically meaningful results between superflab and CDIM. For PDM, the results obtained with TPS and ion chamber measurements indicated that, it is not suitable to use in radiotherapy application due to its material properties. For the simulated skin dose values obtained at five random points on the scar tissue, the comparison of Superflab and CDIM TPS calculation results were not statistically significant. CONCLUSION: The CDIM is easy to prepare and apply on irregular mastectomy scar tissue and it prevents formation of air gaps in the application surface. Especially for curved anatomical regions such as scar tissue, inclusion of the bolus material in treatment planning protocol will reduce dose uncertainty in application. It is safe to use CDIM as an alternative to Superflab in radiotherapy application, whereas PDM is not useful in clinical practice due to its material properties.

Polyvinyl-siloxane (PVS) is a modified condensation silicon that has found applications in the field of dental impression materials thanks to its high biocompatibility and the ability to be modeled...

During impressions, bacteria, viruses, and fungi remain on the impression material, representing a significant risk for the medical team (dentists, dental assistants, and laboratory technicians). Impression disinfectants have been introduced into dentistry to reduce the risk of cross-infection. This study was performed by examining the surface disinfection of five commonly used impression materials in prosthodontics: alginate-Tropicalgin (Zhermack®), condensation silicone-Zetaplus (Zhermack®), Oranwash L (Zhermack®); and addition silicone-Elite HD + Putty Soft (Zhermack®), Elite + Light Body (Zhermack®) after the disinfection with three disinfectants: Zeta 3 Soft (Zhermack®), Zeta 7 Spray (Zhermack®) and Zeta 7 Solution (Zhermack®). Before disinfection, the impression materials were contaminated with Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, and Candida albicans ATCC 10213. Our results demonstrate the efficacy of the two examined specific disinfectants in reducing cross-infection risk. The surface disinfectant-spray is not adequate for impression disinfection. A high number of bacterial colonies were found on the surface of all impressions disinfected with this spray. The immersion-disinfection method effectively eliminates the risk of cross-infections (Kruskal–Wallis test showed a p < 0.001).

Background: A dental impression is a negative imprint of an oral structure utilized to produce a positive replica of the structure that can be used as a permanent record or in the production process of a dental restoration. Hence; the present study was undertaken for assessing the accuracy of two different dental implant impression techniques. Materials & methods: For reference model, an edentulous mandibular cast with four implant analogues in the anterior region was used. For the present study, two different types of impression trays were used as follows: Closed custom tray, and Open custom tray. The impressions were allowed to set for 10 minutes under a standard load of 500 gm. All the impressions were poured using the same quantity of Type IV dental stone. The casts were subjected to measurement after 24 hours to simulate clinical situation. All the results were recorded in Microsoft excel sheet and were analysed by SPSS software.Results: Mean error obtained in closed custom tray technique was 0.028 while mean error obtained in open custom tray technique was 0.23. While analysing statistically, significant results were obtained. Conclusion: Better results are obtained when open custom trays were used.

Introduction: Dental professionals are at the risk of exposure to wide varieties of microorganisms from blood and saliva of patients to airborne infection from microbial-laden aerosols and spatter created during laboratory procedures. Dental laboratories are usually disregarded when planning effective infection and exposure control measures. Contaminated impression may act as a vehicle for transmission of infectious agents. Objective: The objective of this study was to assess the practice of dental technicians towards infection control and to evaluate practice of the same for dental impressions in commercial dental laboratories. Methods: Self-administered standard questionnaire was distributed to 35 dental laboratories and 31 participated in the study. The answers were collected by the investigators themselves. The data obtained were computed and analysed to find the results. Results: Among all dental laboratories, 21 (67.75%) ensure dental impression is disinfected in clinic. 18 (58.06%) wear gloves when receiving clinical items and 27 (87.10%) transfer the items in separate sealed plastic bag. Of all, 25 (80.64%) of the dental laboratories have separate receiving area for dental impression and 23 (74.19%) of the dental technicians continue to wear protective barriers (gloves, mask and apron) during work. In total, 29 (93.55%) of the dental laboratories confirmed, none of their technicians has ever attended any course or training in cross-infection control. Conclusion: The practice of cross-infection control for dental impression in commercial dental laboratories is acceptable. There should be proper guidelines from the regulating body on the protocol of infection control and laboratory waste disposal.

Dental materials are inevitably contaminated with oral microorganisms. To prevent transmission of infectious diseases, impressions need to be disinfected. In the present study, we examined the disinfection effects on impression materials and biofilm removal by sodium dichloroisocyanurate (SDIC). Exponentially growing Streptococcus mutans, Escherichia coli, Staphylococcus aureus and Candida albicans, and dental plaque bacteria were suspended in phosphate buffered saline (PBS) and exposed for 1, 5 and 10 min to 1 mL of the 10 ppm, 100 ppm, 1,000 ppm, and 10,000 ppm SDIC solutions. The bactericidal effect was evaluated by colony forming units of each microorganisms. Moreover, the effect of SDIC solution on S. mutans biofilm was examined. Bactericidal effects of SDIC solutions on oral bacteria on dental impression surfaces were assessed and the surface quality of dental casts after immersion in SDIC solution for 30 min was observed under a scanning electron microscope. The number of all bacterial strains, including plaque bacteria, were significantly decreased by SDIC solution treatment in a dose-dependent manner. Significant S. mutans biofilm removing activity of SDIC was observed in 1,000 and 10,000 ppm solution. The number of oral bacteria adhering to the surfaces of impressions markedly decreased following 10-min immersion in the 1,000 ppm SDIC solution. The 30-min immersion of dental impression in the 1,000 ppm SDIC solution did not adversely affect the surface roughness of dental casts. The results indicate that SDIC Solution is useful to deactivate oral bacteria on dental impression.

Dental impression compound is a rigid impression material mainly used for prosthetic work in dentistry. It is usually manipulated in a temperature controlled water or air bath. When there is a fracture of bilateral parasymphysis there are chances lingual splaying and thus causing hampering of occlusion and function for the patient. Thus, we propose that impression compound is a quick, economical option for prevention of lingual splaying during bilateral parasymphysis fracture reduction. The hardened impression compound will act as a lingual splint in order to prevent splaying of the lingual cortical bone which will help in ease of fracture reduction of bilateral parasymphyseal region.

Three-dimensional (3D) computer-aided planning has truly revolutionized orthognathic surgery (OGS) treatment, but no study has compared the traditional hybrid and full 3D digital planning models. This study compared these virtual planning models in the treatment of asymmetric maxillomandibular disharmony.Young adult patients with an asymmetric skeletal class III deformity who underwent 3D computer-aided 2-jaw OGS using hybrid (alginate dental impression, 2D cephalometric tracings, manual-guided stone model surgery, occlusion setup, and splint fabrication; n = 30) or full digital (laser-scanned dentition, 3D cephalometric tracings, virtual-based occlusion setup and surgery, and computer-generated surgical splint; n = 30) planning models were consecutively recruited. Preoperative and postoperative 3D cephalometric analyses (dental relation, skeletal assessments based on sagittal and frontal views, and soft tissue evaluations) were adopted for intragroup and intergroup comparisons. Postoperative patient-perceived satisfaction with facial appearance was also recorded.Both hybrid and full digital planning groups had significant (all P0.05) improvements after surgery with respect to facial convexity, incisor overjet, and frontal symmetry parameters. The full 3D digital planning-based OGS treatment had similar (all P0.05) 3D cephalometric-derived outcomes (preoperative, postoperative, and treatment-induced change data) and patient-perceived outcomes compared with the traditional hybrid 3D planning method.For the decision-making process in selecting the planning model, multidisciplinary teams could consider additional parameters such as patient comfort, storage needs, convenience for data reuse, overall planning time, availability, and costs.

Implantology has come a long way to be mainstay in routine dental rehabilitation. An extremely high level of accuracy is essential in successful surgical placement of implants and development of the prosthetic solutions which should work like or better than natural healthy teeth. An equally accurate replication of the clinical situations in a physical or virtual mode is required before and during the treatment for the planning or execution of the prosthetic phase by the laboratories. Impression making and modelling tools form a vital segment in the armamentarium of implantologists and these techniques need a high level of skill development.

Background . This study aimed to evaluate the effect of different pouring times and spacer thicknesses on the three-dimensional accuracy of casts made of 3D-printed custom trays. Methods. A partial edentulous maxillary model was scanned for fabricating custom acrylic trays. Twenty custom trays were created using a CAD/CAM system and divided into two groups in terms of their spacer thicknesses (2 mm and 4 mm). All the trays were designed with 2-mm thickness, multiple retentive holes measuring 2 mm in diameter, and three interior seating stops (two on the edentulous ridge and one on the incisal edge of the central incisors). Impressions were made using monophasic polyvinyl siloxane and poured in two different times (one hour and 24 hours after removal) with type IV dental stone. All the casts were scanned to measure three distances (inter-buccal cusps, inter-palatal cusps, and inter-fossa distances) between the two first premolars. The data were analyzed with two-way ANOVA and Bonferroni test at a significance level of 0.05. Results. There was no significant difference between the 3D accuracy of casts made using two different spacer thicknesses poured at 1-hour and 24-hour intervals. However, there was a difference between casts made after 1 hour and 24 hours when using custom trays with 2 mm of spacer thickness in terms of inter-buccal distance. Conclusion. There was no significant difference between the accuracy of casts made using custom trays with either 2 or 4 mm of spacer thickness, which were poured 1 hour or 24 hours after tray removal.

A novel human coronavirus(SARS‐CoV‐2) causing a severe acute respiratory syndrome, coronavirus disease 2019 (COVID‐19), was reported in Wuhan, China at the end of 2019(Wang, Horby, Hayden, & Gao,2020; Khan, Ali, Siddique, Nabi, 2020).The infectionhas an estimated incubation period of 1‐14 days and its clinical manifestations and symptoms include cough, fever and shortness of breath (Zhuet al., 2020).

Objectives: This study aimed to evaluate the efficacy of different solutions used to disinfect Alginate impression material.Materials and Method: Twenty Alginate impressions for the maxillary arch of five patients recently completed their treatment (four impressions for each patients) were taken swabbed before and after disinfecting them with Chlorhexidine, Desident CaviCide and Alcohol and one just washed with tap water as a control. Swabs were cultured to detect bacteria and fungi and count them.Results: Only Streptococcus bacteria were detected with no fungal contamination. Tap water reduced the bacterial count while other disinfectants killed the bacteria completely.Conclusions: Chlorhexidine, Desident CaviCide and Alcohol can be used to disinfect the dental impression effectively.

Zielsetzung: Ziel dieser Studie ist es, die Genauigkeit von konventionellen Gipsmodellen, analogen Kunststoffmodellen und digitalen Modellen in der OnyxCeph- und Ortho-Analyzer-Software zu untersuchen. Zum Vergleich wird dafür der durchschnittliche Peer Assessment Rating Index (PAR-Index) jeder Modellart ermittelt. Anschließend werden diese PAR-Werte mit denen des Ursprungsmodells verglichen, um eine Aussage darüber treffen zu können, welche Art der Abformung und Modellherstellung für die Modellanalyse in der Kieferorthopädie zu bevorzugen ist. Methodik: Ein Mastermodell wurde durch zwölf PAR-zertifizierte Behandler mittels PAR-Index vermessen und dessen Mittelwert gebildet. Anschließend erfolgte die Abformung des Mastermodells durch Alginat und mittels direkter Digitalisierung durch einen Intraoralscanner. Auf konventionellem Wege wurden Gipsmodelle hergestellt und der Scandatensatz wurde sowohl für den Druck von Kunststoffmodellen durch einen Stereolithografie-Drucker, als auch für die Modellerstellung in der OnyxCeph- und OrthoAnalyzer-Software genutzt. Die vier verschiedenen Modellarten wurden anschließend durch 120 Behandler aus drei verschiedenen Berufsgruppen – Kieferorthopäden, Studenten und Assistenten – vermessen und die ermittelten durchschnittlichen PAR-Werte der Gruppen mit dem des Mastermodells verglichen. Ergebnisse: Es konnten keine signifikanten Unterschiede zwischen den Mittelwerten des PAR-Index bei den Modellarten Mastermodell, Gipsmodell, Kunststoffmodell und den digitalen Modellen in OnyxCeph und OrthoAnalyzer festgestellt werden. Des Weiteren konnten keine signifikanten Unterschiede zwischen den Mittelwerten des PAR-Index bei den Behandlerarten Goldstandardvermesser, Kieferorthopäden, Studenten und Assistenten festgestellt werden. Schlussfolgerung: Alle vier Modellarten zeigen eine ausreichende Validität bei der Ermittlung des PAR-Index. Es konnten keine verbesserten Werte in Bezug auf Präzision und Richtigkeit beim konventionellen Modell im Vergleich zu den digitalen Modellen festgestellt werden. Die digitale Abformung und Modellanalyse ist somit als gleichwertig zur konventionellen analogen Abformung zu betrachten. Dieser Umstand sollte in Zeiten von ständiger Digitalisierung auch in der modernen Zahnarztpraxis Anwendung finden. Für eine umfassendere Bewertung in Bezug auf ökonomische und ökologische Faktoren sind weitere Studien wünschenswert., Objective: This study aims to investigate the accuracy of conventional plaster models, analog plastic models and digital models in OnyxCeph and OrthoAnalyzer. To examine this the average Peer Assessment Rating Index (PAR Index) of each model type is determined and compared to those of the original model to determine which form of impression and model is preferred for analysis in orthodontics. Methods: First, the measurement of one original (master) model were taken by twelve PAR-certified dentists using the PAR index and the mean thereof were calculated. Afterwards a conventional alginate impression and an intraoral scan of the master model were taken. Plaster models were produced and the scan data set was used for printing plastic models with a stereolithography printer as well as creating digital models in the OnyxCeph- and OrthoAnalyzer- software. Later on 120 examiners from three different professions - orthodontists, students and assistants - measured the four different types of models. Lastly the average PAR values for each group were compared to the primarily calculates mean measurement of the master model. Results: No significant differences were found between the average PAR index values of the master model, plaster model, acrylic model and the digital models in OnyxCeph and OrthoAnalyzer. Furthermore, no significant differences between the mean values of the PAR index were found for the examiners of gold standard, orthodontist, student and assistant. Conclusion: All model types show sufficient validity in determining the PAR Index. There were no improved values in terms of precision and correctness for the conventional model compared to the digital models. The digital impression and analysis could therefore be considered equivalent to the conventional method. In times of constant digitalization, the results of this study should be considered in modern dental treatment. Further studies should be done for a more comprehensive assessment in terms of economic and ecological factors.

Restorative dentists are faced with a dilemma: they needs to be aware of the most recent developments in order to be able to offer state-of-the-art care but they also have to be able to identify which of the many innovations are superfluous. In this doctoral dissertation the focus was on the role of digital production and procedures in restorative dentistry, and in oral implantology in particular. The variety of studies performed revealed that patients prefer to have impressions taken digitally rather than with dental impression putty and that digital impressions can be taken more quickly. Modern restorative materials are often made of ceramics, such as the white and aesthetically appealing zirconium dioxide (3Y-TZP). It was revealed that zirconia when used as abutment material for implant-born restorations showed no signs of degradation after 1 year of clinical use and was more or less as strong as it had been in the beginning. Milled composite resin crowns, however, that were cemented to them did not adhere well to the ceramic.Prothetische tandartsen staan voor een dilemma: zij moeten op de hoogte zijn van de nieuwste ontwikkelingen om moderne zorg te kunnen bieden, maar moeten ook kunnen herkennen welke van de vele innovaties overbodig zijn. In dit promotieonderzoek stond de rol van digitale productie en behandelingen binnen de restauratieve tandheelkunde, in het bijzonder de orale implantologie, centraal. Uit de diverse onderzoeken bleek onder andere dat patiënten het nemen van een digitale afdruk prettiger vonden dan een afdruk met afdrukpasta en dat een digitale afdruk bovendien sneller gaat. Moderne restauratiematerialen zijn vaak gemaakt van keramieken, zoals het witte en esthetisch fraaie zirkoniumdioxide (3Y-TZP). Het bleek dat zirkoniumdioxide opbouwen voor implantaatkronen na 1 jaar klinisch gebruik geen tekenen van degradatie vertoonden en min of meer even sterk waren als aan het begin. Gefreesde composietkronen die eraan werden verlijmd hechtten echter niet goed aan dat keramiek.

PURPOSE The increased use of CAD systems can generate doubt about the accuracy of digital impressions for angulated implants. The aim of this study was to evaluate the accuracy of different impression techniques, two conventional and one digital, for implants with and without angulation. MATERIALS AND METHODS We used a polyurethane cast that simulates the human maxilla according to ASTM F1839, and 6 tapered implants were installed with external hexagonal connections to simulate tooth positions 17, 15, 12, 23, 25, and 27. Implants 17 and 23 were placed with 15° of mesial angulation and distal angulation, respectively. Mini cone abutments were installed on these implants with a metal strap 1 mm in height. Conventional and digital impression procedures were performed on the maxillary master cast, and the implants were separated into 6 groups based on the technique used and measurement type: G1 - control, G2 - digital impression, G3 - conventional impression with an open tray, G4 - conventional impression with a closed tray, G5 - conventional impression with an open tray and a digital impression, and G6 - conventional impression with a closed tray and a digital impression. A statistical analysis was performed using two-way repeated measures ANOVA to compare the groups, and a Kruskal-Wallis test was conducted to analyze the accuracy of the techniques. RESULTS No significant difference in the accuracy of the techniques was observed between the groups. Therefore, no differences were found among the conventional impression and the combination of conventional and digital impressions, and the angulation of the implants did not affect the accuracy of the techniques. CONCLUSIONS All of the techniques exhibited trueness and had acceptable precision. The variation of the angle of the implants did not affect the accuracy of the techniques.

AIM This study was done to determine more accurate impression technique and splinting method for multiple implant impressions in edentulous patients. MATERIALS AND METHODS A prefabricated maxillary reference model was taken on which four implants were placed parallel to each other using vertical milling machine. Forty custom trays having different tray designs were fabricated using autopolymeri-zing acrylic resin on the stone cast obtained from the reference model. A total of 40 samples (n = 40) were divided into five groups, in which group I included casts obtained from impressions made with closed-tray technique, group II: open-tray impression technique, group III: open-tray impressions splinted with acrylic, group IV: open-tray impressions splinted with light cure material, and group V acted as a control group (reference model). Casts obtained were poured with dental stone. The interimplant distances were checked using coordinate measuring machine to evaluate the three-dimensional (3D) positional accuracy in X, Y, and Z axes. RESULTS Casts obtained from impressions made with closed-tray technique showed highest mean deviation from the reference model while those obtained from open-tray splinted with light cure showed the least deviation. The casts obtained from open-tray nonsplinted and open-tray acrylic splinted showed intermediate mean deviations. CONCLUSION The casts obtained from open-tray impression technique were more accurate as compared with the closed-tray technique. Among splinting, the impressions obtained from light cure splinting showed more accuracy than the impressions obtained from acrylic splinting. CLINICAL SIGNIFICANCE The accuracy of the multiple implant impression is influenced by the type of impression material used which ultimately leads to an accurate cast on which precisely fitting prosthesis is fabricated. Several factors including material accuracy, time span before the impression is poured, and extent of intraoral undercuts are to be kept in mind while choosing an impression material.

The dimensional stability of dental impression materials is one of the variables that contribute to the accuracy or to the inexactitude of dentures. The rheological properties of several dental impression materials were determined by amplitude and frequency sweep tests. Deformation, storage modulus G’, loss modulus G” and complex viscosity η*were studied for each sample. Moreover, the texture, the stability of the shape, the capacity of distribution on different surfaces and the stability to storage for a long period of time were investigated. All these samples, characterized by a gel structure with G’>G”, are suitable as impression materials. Irreversible hydro-colloids) may be used for different kind of impressions because of their fidelity and elasticity; they also present medium time elasticity and may be easily prepared.

The goal of disinfection in the dental office is to prevent the spread of infection from one patient to another and maintain the safety of the dental care providers. Prevention of cross infection has significant effect on infection control. The standard procedure of rinsing impressions under tap water immediately after removal from the mouth eliminates microorganisms along with saliva and blood. A broad search on published literature was done using the keywords impression materials, disinfection method, and sterilization of dental impression from 1980 to 2016 in Medline, Google Scholar, the internet, and textbooks. This article critically analyzes the various published methods of dental impression disinfection in dentistry.

Statement of problem Proper marginal, axial, and occlusal adaptation of dental restorations is essential for their long-term success. Production protocols including digital impression systems have been developed, but little information is available on the adaptation of zirconia restorations produced via them. Purpose The purpose of this in vitro study was to compare the effects of digital impression protocols on the marginal, axial, and occlusal adaptation of zirconia copings. Material and methods Thirty extracted human maxillary premolar teeth without caries or defects were used. The teeth were prepared for zirconia crowns and randomly divided into 3 groups. Zirconia copings were designed at a thickness of 0.5 mm with 30 µm of simulated die spacer starting 1 mm from the margin of preparations. They were produced using computer-aided design-computer-aided manufacture (CAD-CAM) protocol with a conventional impression (group Cn) and 2 different production protocols with digital impressions (group C) and group Tr. The marginal, axial, and occlusal discrepancies of these copings were measured using the silicone replica technique with stereomicroscopy at ×50 magnification, and the data were analyzed with 1-way ANOVAs (?=.05). Results The mean marginal discrepancy values were 85.6 µm for group Cn, 58.7 µm for group C, and 47.7 µm for the Tr group. Significant differences were found among the production protocols in marginal, axial, and occlusal discrepancies (P.05), and group Tr revealed the lowest axial discrepancy (P.05). Conclusions The copings produced with the aid of digital impression systems exhibited better marginal and occlusal adaptation than those of the copings produced with the aid of conventional impression. © 2016 Editorial Council for the Journal of Prosthetic Dentistry

Purpose To develop a reliable and valid instrument for the comprehensive assessment of patients' burdens during dental impression making, the Burdens in Dental Impression Making Questionnaire, BiDIM-Q. Materials The item pool was generated in a convenience sample of 20 prosthodontic patients using semi-structured face-to-face interviews. The final instrument was tested in 145 consecutively recruited patients, and psychometric properties of the BiDIM-Q were determined. Four different impression materials were used according to the manufacturers' instructions and indications: alginate, c-silicone, polyvinylsiloxane, and polyether. Results The final BiDIM-Q consisting of 12 items showed sufficient reliability, indicated by Cronbach's alpha of .82 and an average inter-item correlation of .29. Validity was supported by Pearson correlation coefficients for the correlation between the instrument's total score with the patients' overall satisfaction rating ( r =.63), and by the correlation matrix for the correlations of the patients' perceptions with the practitioners' satisfaction ratings. Overall, patient perceived burdens were low with highest burdens observed when using polyether in partially dentate patients for pick-up impressions, while lowest burdens were reported when using c-silicone for impressions of edentulous jaws. Conclusion The BiDIM-Q is a reliable and valid tool for assessing patient-based process-related quality of care in dentistry allowing a deeper insight into patients' perspective during dental impression making.

Background: The frequency of cardiovascular disease increases with age. Dental procedures as stressful triggers may cause unpredictable changes in the function of the cardiovascular system. Impression is an inevitable dental procedure. Objectives: Since upper jaw impression stimulates the sensory terminals of nerves, especially vagus, this study was conducted to evaluate the changes in blood pressure, heart rate, and pulse pressure due to dental impression. Methods: This observational study was performed on individuals who referred to the Prosthetic Department of Yazd Dental School. The sample was composed of 46 individuals, including 26 women and 20 men, who fulfilled the inclusion criteria and signed written consent forms. The severity of gag reflex was measured and just individuals with moderate gag reflex entered the study. Impression was carried out in the upper jaw in the upright position and rest condition. Blood pressure, pulse rate, and pulse pressure were measured and compared before and immediately after impression procedure. Taking into account the significance level of 5%, the test power of 80%, and blood pressure standard deviation of 4, and to achieve a significant difference of at least 2 mmHg in the groups, 46 people were needed in the study. Data were analyzed by SPSS 18 and t test. Results: Systolic and diastolic blood pressure, heart rate, and pulse pressure were measured before and after dental impression. The difference between men and women was significant only for pulse pressure at both stages (P = 0.02). There was also a statistically significant difference in pulse pressure before and after impression only in women (P = 0.049). There was no significant difference in men. Conclusions: Common dental procedures such as impression could not significantly alter blood pressure and pulse rate.

Dental cast is an indispensable part of a routine diagnostic and therapeutic procedure. Conventional impression materials, e.g. alginate and polyvinyl siloxane are used for capturing intraoral details and subsequent dental casts pouring. Intraoral scanners (IOS) were introduced in dentistry in the early 1980s and became a valid alternative to those procedures. IOS are fast, accurate and more pleasant for a patient than conventional impression techniques, making it necessary to introduce that technique in Dental School's curriculum. Eighteen dental students and recent graduates performed both techniques on each other and filled two two-part questionnaires (from patient's and practitioner's perspective ; before and after impression-taking) to reveal their preferences and expectations from both techniques. The results showed a statistically significant difference in time needed for digital and conventional impression, with digital being faster. After the scanning, all participants answered that digital impression technique would spare more time in their office. Majority of participants thought that digital techniques would completely replace conventional techniques during their lifetime and that attitude hasn't changed afterwards. Results of this pilot study showed participants' inclination towards new impression techniques and need for their implementation in Dental School's curriculum.

Summary Objective Comparison of dental measurements between conventional plaster models, digital models obtained by impression scanning and plaster model scanning. Purpose To evaluate and to compare the accuracy and reliability of tooth size, arch width and Bolton tooth size discrepancy measurements on 3 Dimensional (3D) digital models obtained by plaster dental model scanning, dental impression scanning and conventional plaster models. Material and methods This study was carried out on the maxillary and mandibular dental models of 25 patients with Angle Class I molar relationship and minimal crowding. Mesio-distal dimensions of the teeth, intercanine and intermolar arch width, and Bolton tooth size discrepancy measurements were calculated by conventional methods on plaster models, digital methods and on 3D models obtained from plaster model scanning and impression scanning. All measurements were repeated after three weeks for each of the investigated methods. Reliability of measurements was evaluated by Dahlberg formula and Pearson Correlation Coefficient. Comparisons of dental measurements between three methods were achieved with ANOVA Test. Results The repeated measurements were highly correlated for all methods. Method error was found within clinically acceptable limits. There was no significant difference between dental measurements on plaster dental models, digital models obtained from plaster dental model scanning and dental impression scanning. Results showed the methods being highly reliable and accurate for tooth size, arch width and Bolton analysis at total and anterior proportion calculation. Conclusion Digital measurements of tooth size, arch width and Bolton tooth size discrepancy on digital models obtained from plaster dental model scanning and dental impression scanning showed high accuracy and reliability. There was no significant difference between the three methods for dental measurements.

Gypsum has been used for many years as a dental impression, modeling, and bite recording material. Availability, price, mechanical and physical properties, such as dimensional stability, have made gypsum as the most popular dental modeling and investment materials. The physical and chemical structures of gypsum particles, as well as their manipulation characteristics, play an important role in their properties. This chapter aims to provide the dental professions and students with basic and practical information on currently used dental modeling and investment materials covering desirable qualities, composition, production, and applications of different types of gypsum products. Also, the setting reaction and setting expansion of gypsum products as well as manipulation of gypsum products will be discussed. Finally, advanced technologies and their application in dental die production will be explored.

Background Gagging condition is among factors contributing to avoidance behavior to seek the dental treatment, and rigorous management is still under investigation. This study aims to explore the effect of listening to the self-preference music in reducing the gagging condition during dental impression procedure towards gagging patient. Physiology and psychological impact to the procedure with and without musical intervention are investigated. Method and material A group of twenty-five patients that will undergo impression procedure was randomly selected. Self-reported Gagging Problem Assessment (GPA-pa-SF) questionnaires was then administered to determine the severity of gagging. Maxillary impression was taken twice within the same patient in two different time intervals (1st without any intervention and 2nd with musical intervention). During both procedures, the pulse rate/minutes (BPM) and arterial oxygen saturation of haemoglobin (SpO2%) were recorded and psychometric assessment was evaluated through the Oral Health Impact Profile (OHIP-14). Result Mean value of BPM was significantly reduced with music (p Conclusion Listening to self-preference music during impression taking had improved physiology and psychology of gagging patients thus, can be attributed to the better dental management.

The efficacy of 1 % sodium hypochlorite and 2 % glutaraldehyde disinfectant sprays on impression materials (alginate and addition silicone rubber-based impression material) was tested qualitatively and quantitatively for the presence of microflora on untreated (control group) and disinfected impression surfaces after 48 h of incubation using nutrient agar culture medium. Impressions were made of 60 dentulous volunteers aged 20–50 years who were apparently free from medical problems. The colony-forming units (cfu) were counted and compared with the control group. The control group showed growth of viridians streptococci, Streptococcus pneumonia, diphtheroids, and Neisseria. The alginate control group showed more microflora compared with the silicone impression surface of both the control group and the study group. Use of 1 % sodium hypochlorite yielded better results than did 2 % glutaraldehyde.

Even through nowadays technology and robotics seem to have taken a front seat on the medical field, there are still conventional methods being used in dental medicine, especially related to impression techniques. Elastomers such as silicone rubbers are widely used as impression materials for their suitable properties and behavior in dentistry. As the long-term success of the prosthetic therapy relies on the impression stage, it is important to know both the advantages and disadvantages of such materials. Nowadays in vitro and in vivo studies are being conducted to establish the precision and accuracy of these materials. In this study we report comparatively a number of characteristics determined by us under identical conditions for four such materials. Structural studies (through IR and XRF), morphology (through AFM and SEM) and surface (water contact angle) were performed. Based on the results obtained we can identify more or less significant differences between some characteristics, which could help to indicate the right material depending on the case requirements.

Background: Dental impression is a crucial part of the process of constructing a well-fitting prosthesis. In the clinical scenario, impressions can act as a vehicle for the transfer of bacteria and fungi. Therefore, an attempt was made to evaluate the dimensional accuracy of the newly introduced polyvinyl siloxane (PVS) impression material upon autoclaving and comparing it to the traditional means of chemical disinfection. Materials and Methods: A cross-sectional comparative in vitro study was conducted. Three groups were made for testing different sterilization methods. The sample size for the study was kept as 30 observations in each of the three groups. Test samples were prepared by making an impression of the die using the putty-wash technique. Statistical analysis was done by applying unpaired t-test, paired t-test, one-way analysis of variance (ANOVA) and post hoc Tukey's honestly significant difference (HSD). Results: Initial mean of samples of group I were compared to A (actual measurement of metal ruled block = 24.960), a dimensional change of 1.6% was found. Similarly, in group II, a change of 1.59% was found and in group III the change was 1.7%. There was mean shrinkage of 24.557 mm in group I, 24.586 mm in group II, and 24.535 mm in group III and these changes were found statistically significant. Conclusion: Dimensional changes in the impression material after disinfection with 2% glutaraldehyde were considered high compared to autoclaving and, hence, it may not be advisable to disinfect this material with 2% glutaraldehyde.

AIM The aim of the present study was to evaluate the marginal and internal fit of zirconium fixed partial denture using different impression techniques. METHODS A Nissin Typodont model, including maxillary central incisor and canine with missing lateral incisor, was selected for the present study. Thirty zirconium frameworks were fabricated following three impression techniques (N = 10), conventional silicone impression (group C), scanned dental impression (group S), and Trios 3 (3Shape) intraoral scanner (group T). An extra-fine milling strategy was applied. RESULTS Group T had the smallest discrepancy compared to groups C (P = 0.006) and S (P = 0.052) at the marginal level, whereas it was larger at the incisal tip. Discrepancies in group T were smaller than group C (P = 0.004) when measured at the axial walls, and smaller than group S (P = 0.045) when measured at the chamfer area for the central teeth only. Samples in group T showed a greater percentage of equally extended restorations (52.5%), while other groups were mainly underextended (group C: 63.7%, group S: 68.8%). CONCLUSION Better adaptation was achieved with the intraoral scanner group, except at the incisal tip. Conventional and scanned impressions revealed a greater percentage of underextended restorations.

Purpose Although dental impression disinfection is determinant to reduce the cross-infection risk, some studies have shown that, in real practice, the disinfection procedures vary considerably. Thus, the aim of this study was to evaluate the antimicrobial effectiveness and the impact on the dimensional stability of addition silicone' impressions of water wash and the most clinically used disinfection solutions: 3% hydrogen peroxide, commercial disinfectant MD520 (Durr) and 1% and 5.25% sodium hypochlorite. Materials and methods For this investigation, dental impressions were taken on 16 volunteer dental students. The antimicrobial effectiveness of each procedure was evaluated by pour plate method. The dimensional stability was evaluated using a standardized stainless-steel model, according to ANSI/ADA no19 specification. Results The study results showed that water wash does not alter the dimensional stability of addition silicone impressions but doesn't reduce the microbial load of the material (P>.05). On the other hand, addition silicone disinfection by immersion with 3% hydrogen peroxide, MD520 (Durr), or sodium hypochlorite at 1% and 5.25% does not alter the dimensional stability significantly but reduces > 99.9% of the microbial load of the impressions (P Conclusion Addition silicone impressions should always be disinfected after water wash in order to reduce effectively the cross-infection risk. All disinfectants tested showed high antimicrobial efficiency without significant changes in three-dimensional shape of impressions. Hydrogen peroxide and sodium hypochlorite are of particular importance because are easily accessible in dental setting. The less explored hydrogen peroxide could be a valuable alternative for silicone impressions disinfection.

PURPOSE To clarify the relationship between residual ridge morphology and pressure distribution of the alveolar bone surface during dental impression procedures. MATERIALS AND METHODS Seven experimental models of the mandibular posterior residual ridge with the same ridge morphology but different mucosa (ie, silicone material) thicknesses and bone (ie, plaster) shapes and sizes were fabricated. The pressure on the bone surface was recorded using a pressure sensor sheet. The data from each model were compared using the Kruskal-Wallis test, and P < .05 was considered statistically significant. RESULTS Even with the same ridge morphology, the distribution of the impression pressure on the bone surface differed according to the mucosal thickness and bone shape and size. Pressure tended to concentrate on sharp edges and prominences of a slope and became more widely distributed as the mucosal thickness increased. CONCLUSION Within the limitations of this experimental study, the morphology of the residual alveolar ridge (bone and mucosa) appears to be a significant influencing factor for the pressure distribution during impression procedures.

Background: The aim of this case report is to describe the innovative concept of a prototype use in a digital implant workflow. A prototype is required for simultaneous evaluation of the accuracy of a dental impression and esthetic and functional parameters before final framework realization. Case Description: Three digital impressions were obtained to create a master file, which contained information on the 3-dimensional (3D) position of the implant, the gingival architecture, and the esthetic and functional features of the provisional restoration. A stereolithographic master model (SMM) featuring implant analogs was 3D printed. Two prototypes were realized with the use of 2 different modalities. The first resin prototype (A), which lacked implant connections, was produced with the use of a certified digital workflow process. The titanium connections were luted onto the SMM. The second resin prototype (B), considered experimental, was a single piece with milled implant connections. Both prototypes were tested in the patient by means of visual inspection, finger pressure testing, screw resistance testing, and periapical radiography. In the case of accurate fit of prototype A or B on the SMM and misfit in the patient, the impression should be invalidated. For prototype B, in the case of proper fit in the patient and misfit on the SMM (because of the occurrence of an error during 3D printing, incorrect analog position, or both), the impression should be validated, but the model should be adapted. Conclusions and Practical Implications: The use of a prototype allows the clinician to simultaneously test implant position and esthetic and functional parameters. However, a single-structure prototype could be preferable for the identification of impression inaccuracy.

Introdução: A obtenção de um modelo de trabalho preciso em prótese parcial fixa é fundamental para se atingir o sucesso e está relacionada, principalmente, às técnicas e material de moldagem. Há várias técnicas para obtenção do modelo de trabalho e troquéis para confecção de prótese parcial fixa, dentre elas está a técnica do casquete. Objetivo: Este trabalho tem o objetivo de apresentar uma variação na técnica de reembasamento do casquete confeccionado previamente com resina acrílica convencional. Material e Métodos: Nesta técnica, o casquete é completamente preenchido com resina acrílica (Duralay) em uma única mistura, a qual é manuseada até a fase plástica e então, o conjunto casquete/resina duralay é inserido no dente preparado para copiar a linha de término do preparo. Resultados: A vantagem é que a fase plástica da resina acrílica possui baixa quantidade de monômero livre e adequada consistência para promover o afastamento gengival provocando desconforto mínimo ao paciente e possui adequada consistência para promover o afastamento gengival. Não é necessária a troquelização do modelo. Conclusão: Conclui-se que essa variação técnica tem aplicação clínica simples e eficaz e produz troquéis de gesso muito precisos.

Background/Aim. Dental impressions present a negative imprint of intraoral tissues of a patient which is, by pouring in gypsum, transferred extraorally on the working cast. Casting an accurate and precise working cast presents the first and very important step, since each of the following stages contributes to the overall error of the production process, which can lead to inadequately fitting dental restorations. The aim of this study was to promote and test a new model and technique for in vitro evaluation of the dental impression accuracy, as well as to asses the dimensional stability of impression material depending on the material bulk, and its effect on the accuracy of working casts. Methods. Impressions were made by the monophasic technique using the experimental master model. Custom trays with spacing of 1, 2 and 3 mm were constructed by rapid prototyping. The overall of 10 impressions were made with each custom tray. Working casts were made with gypsum type IV. Measurement of working casts was done 24 h later using a coordinate measuring machine. Results. The obtained results show that the working casts of all the three custom trays were in most cases significantly different in the transversal and sagittal planes in relation to the master model. The height of abutments was mainly unaffected. The degree of convergence showed certain significance in all the three custom trays, most pronounced in the tray with 3 mm spacing. Conclusion. The impression material bulk of 1-3 mm could provide accurate working casts when using the monophasic impression technique. The increase of the distance between abutment teeth influences the accuracy of working casts depending on the material bulk., Uvod/Cilj. Otisak predstavlja negativ intraoralnih tkiva, čijim se izlivanjem u gipsu njihova morfologija prenosi ekstraoralno na budući radni model. Sa laboratorijskog aspekta izrade zubnih nadoknada, izlivanje tačnog i preciznog radnog modela predstavlja prvi i veoma bitan korak, pošto svaka sledeća faza doprinosi daljem povećanju greške tokom izrade, što za krajnji ishod može imati neodgovarajuću zubnu nadoknadu. Cilj istraživanja bio je da se ispitaju novi model i tehnika za in vitro procenu preciznosti zubnih otisaka, kao i da se odredi uticaj količine otisnog materijala na dimenzionu stabilnost otisaka i preciznost izrade radnih modela. Metode. Za uzimanje otisaka korišćena je monofazna tehnika otiskivanja. Individualne kašike sa međuprostorom od 1, 2 i 3 mm napravljene su aditivnom tehnologijom za brzu izradu prototipova. Sa svakom kašikom napravljeno je po 10 otisaka. Radni modeli izlivani su u gipsu tipa IV. Merenje radnih modela vršeno je nakon 24 sata na koordinatnoj mernoj mašini. Rezultati. Rezultati pokazuju da radni modeli napravljeni pomoću sve tri individulane kašike u transverzalnoj i sagitalnoj ravni značajno odstupaju od glavnog dela modela. Visina patrljaka je u većini slučajeva bila kao na glavnom modelu. Stepen konvergencije pokazao je određena odstupanja samo kod kašike sa međuprostorom od 3 mm. Zaključak. Monofazna tehnika otiskivanja i otisni materijal debljine od 1 do 3 mm obezbeđuju izradu preciznih radnih modela. Rastojanje između zubnih patrljaka utiče na preciznost izrade radnih modela u zavisnosti od količine otisnog materijala.

Intranasal foreign bodies arising from dental clinical practice, especially in patients with cleft lip and palate (CLP) occur rarely and are very scarce in the literature. This article reports an unusual case of a dental impression material presenting as a foreign body in the nasal cavity of an adult with repaired CLP who presented for dental prosthetic rehabilitation. To our knowledge, this is only the second report presenting nasal foreign body in a cleft patient arising due to a dental impression procedure.

A nondestructive polyvinyl siloxane (PVS) impression protocol was developed for studying the surface features on joint prostheses with modular junctions after they have been removed from patients. Analysis of the failed joint prostheses reveals that modular junctions consisting of bore-cone tapers can be the site of in vivo fretting and crevice corrosion. While cone taper surfaces are readily analyzed by non-contact profilometric techniques, bore taper surfaces are inaccessible for direct observation. An indirect repeatable method to analyze these inaccessible surfaces was developed, incorporating a commonly used dental impression polymer to achieve a high-detail negative of the bore taper suitable for profilometric measurements. Compared to the actual bore surface, light-viscosity PVS adequately replicated surface features for statistically similar measurements of metrological mean roughness parameters (Sa, Sq), peak-to-valley height parameters (Sz), shape parameters (Ssk, Sku), and spatial parameters (Sm). Surface features as fine as 2.6 μm in size were reproduced, indicating that this technique is applicable to failure analysis studies involving abrasive wear, adhesive wear, and corrosion pits. This indirect and nondestructive method of surface damage analysis can be broadly applied in many industries requiring analysis of inaccessible surfaces, such as machined bores, inner surfaces of pipes, and large parts incompatible with laboratory metrology equipment.

A Sialocele or salivary pseudocyst is due to extravasation of saliva into periglandular tissue due to disruption of gland parenchyma. Various techniques of management have been described in literature; both conservative and surgical management have been documented. We report a simple economical and efficient method to deal with sailocele presenting after neck dissection.

A quality-made dental impression is a prerequisite for successful fixed-prosthodontic fabrication and is directly dependent on the dimensional stability, accuracy and flexibility of the elastomeric impression materials, as well as on the appropriately used impression techniques. The purpose of this paper is to provide a literature review of relevant scientific papers which discuss the use of various silicone impression materials, different impression techniques and to evaluate their impact on the dimensional stability and accuracy of the obtained impressions. Scientific papers and studies were selected according to the materials used, the sample size, impression technique, storage time, type of measurements and use of spacer for the period between 2002 and 2016. In the reviewed literature several factors that influence the dimensional stability and accuracy of silicone impression molds, including the choice of the type of viscosity, impression material thickness, impression technique, retention of the impression material on the tray, storage time before the casting, number of castings, hydrophilicity of the material, release of byproducts, contraction after polymerization, thermal contraction and incomplete elastic recovery were presented. The literature review confirmed the lack of standardization of methodologies applied in the research and their great diversity. All findings point to the superiority of the addition silicone compared to the condensation silicone.