Search

Objectives The aim of this study was to evaluate and compare penetration ability and tensile strength among vinylsiloxanether (VSE), polyether (PE), and polyvinylsiloxane (PVS) elastomeric dental impression materials. Materials and Methods The models were constructed for penetration ability test by simulated gingival sulcus width and moist environment. The 0.05, 0.1, and 0.2 mm of simulated gingival sulcus widths were used. Each simulated gingival sulcus width was impressed 10 repeats per one elastomeric impression material. All extension of elastomeric dental impression materials was scaled by Measuring Microscope (MM-11; Nikon, Tokyo, Japan). On the issue of the tensile strength study, the models were constructed following type 1 of the ISO 37:2017 specifications and/or type C of ASTM.D412 specifications. The two-way analysis of variance (ANOVA) and Tukey's honest significant difference test were performed in the penetration ability test. The one-way ANOVA and Dunnett's T3 test were performed in the tensile strength test. The significance level was set at 0.05. Results PE showed the best extension into all widths of simulated sulcus followed by VSE and PVS, respectively. PVS was significantly higher in tensile strength than VSE and PE, while VSE was significantly higher than PE. Conclusion Penetration ability of elastomeric dental impression materials was depended on gingival sulcus width. The wider the sulcular width, the better the penetration ability of elastomeric dental impression materials. PE presented the best penetration ability, while the novel PVS showed highest tensile strength.

Molding in a fixed prosthesis is one of the most important stages in rehabilitative treatment, as it is there that attempts are made to reproduce dental preparations and adjoining regions by using appropriate materials and techniques. Among the fixed prosthesis molding materials available on the market, the elastomers stand out, which are polymers where the prey occurs through the increase of the chain and the establishment of cross-links. The objective of the study is to present a clinical case and perform a literature review on the use of condensation silicone and addition to molds in Fixed Prosthesis. In this literature review, a survey of PubMed, Scielo and Lilacs data was performed, using the descriptors: Denture, Partial, Fixed; Dental Impression Materials and Elastomers. It is possible to conclude that in the field of Dentistry, the elastomers, among them the condensation-cured and addition-cured silicones, both provide high precision models and are the most used materials in works with fixed partial dentures. Therefore, it is up to the professional to know the properties and adapt to the best group of chosen materials.

Although intraoral scanners have gained in popularity, the traditional impression technique with a custom tray is still useful, particularly when making a definitive impression of multiple abutment teeth. A custom tray can be fabricated with a dental software program, avoiding the disadvantages of the manual laboratory procedures. However, additional module purchasing is necessary. This article presents a digital workflow for designing a custom tray by using an open-source software program.

Conventional implant impressions by using elastomeric impression material have been reported as a more reliable technique for a complete-arch implant record compared with intraoral scanner procedures. Photogrammetry technology may provide a reliable alternative to digital scanning or a conventional impression; however, its accuracy remains unclear.The purpose of this in vitro study was to measure and compare the implant abutment replica positions of the definitive cast with the implant abutment replica positions obtained by the conventional technique, photogrammetry, and 2 intraoral scanners.An edentulous maxillary cast with 6 implant abutment replicas (RC analog for screw-retained abutment straight) was prepared. Three impression techniques were performed: the conventional impression technique (CNV group) by using a custom tray elastomeric impression procedure after splinting the impression copings at room temperature (23°C), photogrammetry (PG group) technology (Icam4D), digital scans by using 2 different IOSs following the manufacturer's recommended scanning protocol, namely IOS-1 (iTero Element) and IOS-2 (TRIOS 3) groups (n=10). A coordinate measuring machine (CMM Contura G2 10/16/06 RDS) was used to measure the implant abutment replica positions of the definitive casts and to compare the linear discrepancies at the x-, y-, and z-axes and the angular distortion of each implant abutment replica position by using a computer aided-design software program (Geomagic) and the best fit technique. The 3D linear gap discrepancy was calculated. Measurements were repeated 3 times. The Shapiro-Wilk test revealed that the data were not normally distributed; therefore, the Kruskal-Wallis test was used to analyze the data, followed by pairwise Mann-Whitney U tests (α=.05).Significant y-axis linear and XY and YZ angular discrepancies were found among the CNV, PG, IOS-1, and IOS-2 groups (P.05). The PG group obtained a significantly higher distortion on the y-axis and 3D gap compared with all the remaining groups (P=.004). The 3D discrepancy of the CNV group was 11.7 μm, of the IOS-1 group was 18.4 μm, of the IOS-2 was 21.1 μm, and of the PG group was 77.6 μm. In all groups, the interquartile range was higher than the median errors from the discrepancies measured from the definitive cast, indicating that the relative precision was low.The conventional technique reported the lowest 3D discrepancy for the implant abutment position translation capabilities of all the implant techniques evaluated. The intraoral scanners tested provided no significant differences in linear distortion compared with the conventional method. However, the photogrammetry system tested provided the least accurate values, with the highest 3D discrepancy for the implant abutment positions among all the groups.

Introduction: Hydrophilicity of dental impression materials is crucial for obtaining an accurate impression and necessary for the production of a well-fitting cast restoration. The most common technique for evaluation of hydrophilicity is a contact angle measurement. The aim of the present in vitro study was to compare the water contact angles of four groups of elastomeric impression materials, before and during setting. Material and methods: Flattened specimens (n=10) of tested impression materials were prepared by the use of a Teflon mold with specific dimensions. A 5μl droplet of deionized water fell on the specimen, and photos were taken using a Nikon D3200 DSLR camera and a 105 mm macro lens (Nikorr, Nikon) in specific time points. Results: The CAD/CAM material showed the highest contact angle measurements. The light body polyvinylsiloxane (PVS) material 1, polyether and vinylsiloxanether material showed comparable contact angle measurements especially at the initial time point. A statistically significant reduction of contact angles was reported during setup time for all PVS, PE and vinylsiloxanether materials, while the most expressed reduction of contact angle measurements, and thus the most significant increase of hydrophilicity were reported for light wash PVS material 2. Conclusions: The CAD/CAM impression material showed the most hydrophobic behavior. PVS materials showed excellent hydrophilicity. Polyether and polyvinyloxanether impression materials presented lower contact angle measurements, and thus superior hydrophilicity, compared with other tested materials initially and during setting. All tested impression materials presented a stepwise development of hydrophilicity during the setting stage., Uvod: Hidrofilnost otisnih materijala ključna je za preciznost otiska i prijeko potrebna za izradu nadomjestka s dobrim dosjedom. Najčešća tehnika za njezinu procjenu jest mjerenje kontaktnog kuta. Cilj ovoga istraživanja in vitro bio je usporediti kontaktne kutove vode u četirima skupinama elastomernih otisnih materijala, prije vezivanja i tijekom vezivanja. Materijali i metode: Spljošteni uzorci (n = 10) ispitanih otisnih materijala pripremljeni su u teflonskom kalupu specifičnih dimenzija. Kapljica deionizirane vode od 5 μL kapnuta je na uzorak, a fotografije su snimljene fotoaparatom Nikon D3200 DSLR i 105 mm makroobjektivom (Nikorr, Nikon) u određenim vremenskim točkama. Rezultati: CAD/CAM materijal imao je najveći kontaktni kut. Rijetki materijali polivinilsiloksan (PVS) 1, polieter i vinilsiloksaneter imali su usporedive mjere kontaktnoga kuta, posebno u početnoj vremenskoj točki. Statistički značajno smanjenje kontaktnih kutova zabilježeno je tijekom postavljanja za sve PVS-ove, PE-ove i vinilsiloksan, a najizraženije smanjenje, pa time i najznačajnije povećanje hidrofilnosti, zabilježeno za rijedak PVS 2. Zaključci: CAD/CAM otisni materijal imao je najhidrofobnija svojstva. PVS materijali imali su izvrsnu hidrofilnost. Polieterski i poliviniloksaneterski otisni materijali imali su manji kontaktni kut, pa tako i veću hidrofilnost u usporedbi s drugim ispitivanim materijalima na početku vezivanja i tijekom toga postupka. Svi ispitani otisni materijali postupno su razvijali hidrofilnost tijekom faze vezivanja.

Evis, Zafer/0000-0002-7518-8162 WOS:000545315200013 PubMed: 31672424 Statement of problem. Recent commercial extended-pour irreversible hydrocolloid impression materials (EPIHIMs) claim to maintain dimensional stability up to 120 hours. However, data regarding their mechanical properties and performance after 120 hours of storage are lacking. Purpose. The purpose of this in vitro study was to test the elastic recovery, strain in compression, and tear strength properties of 5 commercially available EPIHIMs, immediately after preparation and after 120 hours of storage under specific storage conditions. Material and methods. A total of 150 specimens were prepared in accordance with the ISO 21563:2013 standard from 5 commercially available EPIHIMs (Blueprint Xcreme, Kromopan, Alginmax, Hydrogum 5, and Alginelle). The specimens were subjected to elastic recovery, strain in compression, and tear strength tests immediately after specimen preparation (n=5) and after 120 hours of storage inside clear plastic zipper bags held at 23 degrees C (n=5). Data were analyzed with a multivariate analysis of variance (MANOVA) test for brand and duration parameters. Normality of data was analyzed with the Shapiro-Wilk test. The Duncan test or Games-Howell test was used for multiple comparisons (alpha=.05). Results. Elastic recovery and strain in compression values of the EPIHIMs tested were affected by brand and duration parameters (P.05). Data distribution was normal except for Alginmax in terms of the elastic recovery values and Blueprint Xcreme in terms of the strain in compression values (P.05). However, 120 hours of storage led both to a statistically significant decrease in mean strain in compression values of the tested EPIHIMs (P.05) and a statistically significant difference among mean strain in compression values of the tested EPIHIM brands (P.05). However, statistically significant differences were present among mean tear strength values of the tested EPIHIM brands tested immediately after preparation (P

Trying to capture all the details of multiple teeth preparation in one impression is challenging. Techniques have been suggested to extend the working time of an impression material. This article describes a segmental impression technique to accurately capture all the preparation margins while allowing additional impression-making time.

Introduction. The interocclusal registration materials record the occlusal relationship between the natural and /or artificial teeth for planning an occlusal rehabilitation in removable and fixed partial dentures. Aim and objectives. The aim of this in vitro study was to evaluate and compare the accuracy and the three dimensional stability offered by three different types of interocclusal recording materials at storage time intervals of 1 hour and 24 hours. Methods. Three commercially available interocclusal recording materials were used - Group I - Polyether bite registration paste (Ramitec), Group II- Polyvinylsiloxane bite registration material (Imprint), Group III- Bite registration wax (Maarc).The test was carried out using an epoxy resin model. A total of 30 samples were made with each group consisting of ten samples. Three dimensional measurements were carried out by using 3D-Coordinate measuring machine (CMM) at time intervals of 0-1 hour and 0-24 hours in X, Y and Z- axis. Results. Twelve readings were obtained for three axes (4 readings for each sample at 1 axis) and the averages of these four values were noted for a particular axis (X/Y/Z). Statistical analysis was performed using analysis of variance (ANOVA) for comparison among the groups and then Tukey’s honestly significant difference (HSD) tests was performed for comparison among groups at the 0.05 level of significance. Conclusion. Polyvinylsiloxane was dimensionally the most stable material followed by polyether and finally bite registration wax. Dimensional accuracy and stability is influenced by both “material” and “time” factors.

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...

The accurate transfer of the subgingival contours of implant-supported restorations and pontics is essential for providing the dental technician with the necessary information to fabricate an optimal definitive fixed dental prosthesis. However, once the interim restoration is removed to make an impression, the subgingival tissue, which is no longer physically supported, tends to collapse. This digital intraoral and extraoral scanning technique offers a way to transfer the subgingival contours and intaglio surface of the interim restoration to the definitive restoration. In addition, this technique can reduce clinical and laboratory time, as well as the necessity of storing gypsum casts.

Background: Surface detail reproduction (SDR) and dimensional stability of elastomeric impression material play a crucial role in fixed prosthodontics. Aim and Objectives: The aim of this study was to compare the effect of chemical disinfection on SDR and dimensional stability of polyvinyl siloxane (PVS) and polyether (PE) with a new vinyl polyether silicone (VPES) elastomeric impression material. Materials and Methods: A stainless steel mold was made to fabricate the study specimens for nonaqueous PVS, PE, and VPES elastic dental impression materials. Single mix impression techniques with light- and heavy-body consistency of all three materials were used to prepare the test specimens. The specimens were immersed in glutaraldehyde (Cidex) 2.45% and sodium hypochlorite (Hypo) 3.0% disinfection for 15 min (T1) and 12 h (T2) immersion after which dimensional stability and SDR were recorded using stereomicroscope and digital Vernier caliper. Statistical Analysis: The data were analyzed using the one-way ANOVA, paired t-test, Kruskal–Wallis test, and Wilcoxon signed-rank test. Results: Dimensional stability at the T2 time interval showed a highly significant difference for control and glutaraldehyde groups (P < 0.001), whereas a statistically significant difference for Hypo group (P < 0.05). SDR of the three materials when compared at T1 time interval showed a statistically significant difference (P = 0.015). A comparison between two disinfectants at T1 time interval revealed a highly significant difference (P < 0.001), while at T2 interval significant difference was obtained (P = 0.009). Conclusion: VPES impressions display acceptable dimensional stability and SDR for clinical use with immersion disinfection. Although some statistically significant differences in linear dimensional stability and semidefinite programming were observed among VPES, PE, and PVS, but the clinical impact of these differences is minor considering the overall accuracy of casts which was high.

Surgical procedures in posterior area of maxillary might cause an oroantral communication and iatrogenic sinusitis. An undetected oroantral communication can cause the penetration of foreign bodies, such as dental impression materials, in the maxillary sinus, thereby contributing to persistent sinusitis. Given the occurrence of a very rare clinical and medicolegal case of persistent and drug-resistant sinusitis due to radiologically undetected fragments of silicone paste for dental impression in the maxillary antrum, a literature review was pursued through sensitive keywords in relevant databases for health sciences. All retrieved articles were considered and data about the kind of impression materials thrusted into the maxillary sinus, the diagnostic issues, the reported range of symptoms, and the occurrence of medicolegal issues were analyzed. The diagnosis resulted to be quite challenging and belatedly especially in case of healed oroantral communication and when the material retained in the maxillary sinus has similar radiodensity compared to the surrounding normal or inflammatory tissues. The case was then discussed in comparison with the reviewed literature for both clinical and medicolegal issues. Hints were provided to professionals to face the challenging diagnosis in similar rare cases and to avoid the possible related litigation.

The best-fit method is frequently used to evaluate the accuracy of different implant impression techniques. However, the method includes inherent superimposition errors, which may accumulate and become more exaggerated in complete-arch impressions.The purpose of this in vitro study was to evaluate and compare the trueness and precision of conventional open-tray impressions and intraoral digital scans at the implant level in an edentulous maxillary model with 6 implant replicas without superimposition.A master model was fabricated using epoxy resin by duplicating a maxillary edentulous cast that had 6 implant replicas in the right first molar, right first premolar, right lateral incisor, left lateral incisor, left first premolar, and left first molar positions. The conventional open-tray, splinted-coping impression technique was used to fabricate 10 definitive casts (group CI). Intraoral digital scans were performed, after which scan bodies were connected to each implant replica to fabricate 10 digital models (group IOS). For the master model and group CI, a computerized coordinate-measuring machine was used to determine the 3D spatial orientation of the implant replicas. For group IOS, the scan bodies were converted to implant replicas using a digital library, and an inspection software program was used to measure the implant replicas. To compare the accuracies of different impression techniques, a 3D part coordinate system was set to compute the centroid and projection angles of each implant replica. The changes in the centroid coordinates (linear displacement: Δx, Δy, Δz, and ΔD; ΔD=ΔxGroup CI gave more accurate trueness values than group IOS for overall Δx (P.001), Δy (P =.029), Δz (P.001), and ΔD (P.001). Furthermore, group CI had more accurate precision values for Δx, Δy, and Δz. Group IOS exhibited a statistically greater angular displacement in the ZX plane (P=.002), but the difference was only 0.24 degrees. No differences were found between the 2 groups for the angular displacement in the XY plane (P=.529).Conventional open-tray impressions produced significantly smaller linear displacements than the digital scan obtained using an intraoral scanner at the implant level in a complete-arch model.

The need to use a natural alternative for disinfecting dental impression materials, which should be biocompatible and effective, led us to evaluate the efficacy of Aloe vera as a disinfectant by immersion and spray method on alginate impression material and its effect on the dimensional stability of the resultant gypsum cast.The efficacy of the disinfection procedures against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans was evaluated by determining the number of colony-forming units (CFU) recovered after disinfection of alginate discs inoculated with 1x106 CFU for defined intervals with aloe vera solution (99.96%). Dimensional stability was determined from the mean percentage deviation of three measurements that were taken between the fixed points on the casts using a traveling microscope and compared with corresponding measurements from the master model and controls. Statistical analysis of data was determined by analysis of variance.We found out that there is a mean percentage reduction in colony count of S. aureus, P. aeruginosa, and C. albicans after 3 minutes of immersion in aloe vera and after 3 minutes spray disinfection. Complete elimination of all the microorganism cells after 7 min immersion and spray disinfection. There was a statistically significant difference in the increase of the mean anteroposterior (AP) and cross arch (CA) dimension after 3 and 7 minutes immersion in aloe vera.Spraying with aloe vera for 7 minutes was proved to be the most effective disinfection procedure without altering dimensional stability.

PURPOSE To assess the three-dimensional (3D) accuracy of multi-implant impressions for complete arches obtained using 3D printing technology, and to determine the clinical feasibility of this approach by comparing the results obtained with those obtained with conventional impression techniques. MATERIALS AND METHODS A maxillary model matrix with four implant analogs was used to fabricate 10 stone reference models (control) to simulate edentulous patients. Ten 3D-printed impressions were made using polylactic acid custom open trays with component splinting (3D-printed group). To make 10 conventional impressions of the reference models, the poly(methyl methacrylate) open trays with splinting technique was used (conventional group). Impressions were poured with a type IV dental stone, which had been digitalized utilizing a high-resolution laboratory scanner after connecting the polymer scan bodies. Standard tessellation language (STL) datasets from the two groups of stone models were superimposed with the corresponding reference models. The interimplant distances and interimplant angulations for each implant pair were measured for the reference models and for the two test groups' definitive models, to assess 3D deviations. In addition, the mechanical properties of polylactic acid and poly(methyl methacrylate) tray materials were compared by means of three-point loading and tensile bond tests. The Student t test was used to compare the differences in implant position and mechanical properties between the two groups, while implant angulations were analyzed with Wilcoxon's rank-sum test, at P = .05. RESULTS There was less implant-position deviation for the 3D-printed group (mean ± SD: 56.37 ± 12.52 μm) than for the conventional group (71.94 ± 18.86 μm) (P = .014). No significant differences were found in angular deviation between the two groups (P > .05). Flexural strength results suggested that polylactic acid (112.7 ± 1.62 MPa) was stronger than poly(methyl methacrylate) (104.0 ± 2.17 MPa; P < .0001). The tensile bond strength of polylactic acid (0.07 ± 0.005 MPa) was higher than that of poly(methyl methacrylate) (0.03 ± 0.004 MPa; P < .0001). CONCLUSION The 3D-printing multi-implant impression technique could be an alternative to conventional impression techniques for complete arches.

Backgrounds and objectives: Dental impressions present a risk to spread infections among dental practitioners and should be disinfected to prevent the spread of these microorganisms. Different disinfectant materials and techniques can be used to eliminate this threat. The purpose of this study was to evaluate the effect of some disinfectant materials with two different techniques on surface detail and dimensional stability of elastomeric impression materials. Materials and methods: Three dental impression materials were used in this study, Vinyl polysiloxane, Polyether and Vinyl polyether siloxane that were disinfected with sodium hypochlorite, Dettol and Cavex Impresafe by using two techniques, spraying and immersion methods for each. Results: The results of this study showed a significant difference of the dimensions between immediate and 48 hours after disinfection P

Statement of problem A nonpassive fit of implant-supported restorations can jeopardize the biological and mechanical success of the treatment. Data regarding the fit of different impression techniques for the all-on-4 protocol are limited. Purpose The purpose of this in vitro study was to digitally evaluate 4 different impression techniques used with the all-on-4 protocol, with distal multiunit analogs positioned in 4 different angulations. Material and methods Four maxillary definitive cast models with 4 multiunit analogs (T0 32202; NucleOSS) were fabricated according to the all-on-4 treatment protocol. In the anterior region, the analogs were positioned in a parallel direction, whereas in the posterior region, they were positioned in different angulations (0, 10, 20, and 30 degrees). One hundred and sixty models were obtained by using 4 different impression techniques (closed tray without plastic cap, closed tray with plastic cap, splinted open tray, sectioned resplinted open tray) (n=10) and polyvinyl siloxane impression material. Definitive casts and definitive duplicate casts were scanned using a modified laser scanner (Activity 880; Smart Optics Sensortechnik GmbH), and data were transferred to a software program (VRMesh Studio; Virtual Grid Inc). The definitive casts and definitive duplicate cast scans were digitally aligned. Angular and linear deviations in all axes (x, y, and z) of the analogs between definitive and duplicate casts were calculated and subjected to statistical analyses (α=.05). Results Mean angular deviations were in the range of 0.03 to 0.16 degrees, and linear deviations were in the range of 0.10 to 0.75 mm. The increased angulation between impression copings caused higher linear and angular deviations when closed-tray impression techniques were used (P Conclusions Reduced linear and angular displacements were obtained from the open-tray impression techniques compared with the closed-tray impression techniques in the angulated groups. Angular and linear deviations increased with the increase in the angulation of the posterior analog.

The purpose of this study was to assess the precision of 3D-printed splints generated from different dental model offsets.Ten maxillary models were offset by given distances (0.05 mm, 0.1 mm, and 0.2 mm). Digital splints were created by means of the boolean operation. The physical splints were fabricated by means of digital light-processing (DLP) rapid prototyping technologies. A layer of impression material, which could be weighed by means of an electronic analytical balance, was placed in the airspace between the splint and the teeth. We also calculated the shell-to-shell deviations by measuring the 3-dimensional (3D) euclidean distances between the surface points of the scanned splints and the original digital splint and evaluating the results with color-mapping methods.There was a statistically significant difference in the amounts of impression material remaining in the airspace between the 0.0-mm group and the 0.05-mm, 0.1-mm, and 0.2-mm groups (P 0.05), between the 0.05-mm and the 0.1-mm and 0.2-mm groups (P 0.05), and between the 0.0-mm group and the 0.05-mm, 0.1-mm, and 0.2-mm groups (P 0.05). There was a statistically significant difference in shell-to-shell deviations between the 0.05-mm and the 0.1-mm and 0.2-mm groups (P 0.05).3D-printed splints generated from offset dental models (offset 0.05 mm, 0.1 mm, and 0.2 mm) can fit better on the teeth than splints from no-offset dental models. An offset of 0.1 mm is the best choice of parameter for generating the splint.

The technique described allowed an implant custom tray to be fabricated referencing the location of connected impression copings. The technique uses dental computer-aided design (CAD) software and 3D printing technology. The method controls the thickness of the impression material around the impression copings, improving the impression-making process.

Introduction The purpose of this study was to investigate differences in orthodontists' treatment plans based on digital models compared with plaster models. Additionally, we assessed whether digital or plaster models influence the reliability of orthodontists' treatment plans, as well as the amount of time required to arrive at the plan. Methods Sixteen orthodontists planned treatment for 20 patients at 2 time points using either the same or different model formats (digital or plaster). The treatment plan decisions and time spent making the plans were recorded. The permutation test and a random effects model were used to analyze the data. Results The treatment plans arrived at with digital and plaster models were similar. With respect to extractions, the mean difference between digital and plaster formats was 11.9% (95% CI, 7.5%-16.3%). For surgery, the mean difference was 9.4% (95% CI, 5.0%-13.8%). There was no significant difference in the agreement rate between those who viewed models in different formats compared with those who viewed models twice in the same format (P >0.05). The time spent to plan treatment with plaster models was not significantly different from the time spent with digital models (P = 0.87). Conclusions Based on this study, digital models can be substituted for plaster models with no significant differences in the final plans, the reliability of the plans, and the time required to create the plan.

STATEMENT OF PROBLEM Clinical trials are needed to evaluate digital and conventional technologies for providing fixed partial dentures. PURPOSE The purpose of the first part of this clinical study was to test whether complete-arch digital scans were similar to or better than complete-arch conventional impressions regarding time efficiency and participant and clinician perceptions. MATERIAL AND METHODS Ten participants in need of a posterior tooth-supported 3-unit fixed partial denture were included. Three intraoral digital scanners and subsequent workflows (Lava C.O.S.; 3M [Lava], iTero; Align Technology Inc [iTero], Cerec Bluecam; Dentsply Sirona [Cerec]) were compared with the conventional impression method using polyether (Permadyne; 3M) and the conventional workflow. A computer-generated randomization list was used to determine the sequence of the tested impression procedures for each participant. The time needed for the impression procedures, including the occlusal registration, was assessed. In addition, the participant and clinician perceptions of the comfort and difficulty of the impression were rated by means of visual analog scales. Data were analyzed with the nonparametric paired Wilcoxon test together with an appropriate Bonferroni correction to detect differences among the impression systems (α=.05). RESULTS The total time for the complete-arch impressions, including the preparation (powdering) and the occlusal registration, was shorter for the conventional impression than for the digital scans (Lava 1091 ±523 seconds, iTero 1313 ±418 seconds, Cerec 1702 ±558 seconds, conventional 658 ±181 seconds). The difference was statistically significant for 2 of the 3 digital scanners (iTero P=.001, Cerec P

Objective: To evaluate the dimensional changes in three types of alginate following three different delay times after casting. Material and Methods: In this laboratory study, a maxillary arch-shaped stainless steel model was prepared and three pins with similar and determined diameters and heights were placed (one at mid-line and two on the underside of the model) as reference points to compare the dimensional stability of the three types of alginates. A special metal tray was made from the main model. The main moldel was imprisoned by the metal tray, and these were kept for a specific time in a humid environment. Gypsum Type 4 was poured over the impression to obtain 90 gypsum casts for three types of alginate. The dimensions of casts obtained from each alginate were compared in two lateral and anterior-posterior dimensions, they were compared with each other, and the alginates were also compared to the main model. Results: At a time interval of 15 minutes, the dimensional accuracy of the casts obtained from the three types of alginates, with the main model in both anterior-posterior and transverse dimensions was not significantly different (p

Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student’s t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured. RESUMO Objetivo: O presente estudo teve como objetivo avaliar a estabilidade dimensional e manutenção de detalhes de alginatos convencionais e de alta estabilidade por até 5 dias de armazenamento. Métodos: Para esse estudo, foram selecionados dois tipos de alginatos: convencional (Hydrogum) (n = 10) e de alta estabilidade (Hydrogum 5) (n = 10), sendo produzidos com o auxílio de um bloco metálico cilíndrico e um molde metálico em forma de anel (especificações 18, 19 e 25, ANSI/ADA). Para o teste de estabilidade dimensional, dez imagens foram obtidas imediatamente e para cada tempo de armazenamento (15 min, 24, 48, 72, 96 e 120 horas), realizadas por câmera digital. As amostras foram mantidas hermeticamente fechadas em sacos plásticos (23°C). Para o teste de reprodução de detalhes, as amostras foram utilizadas para obter 140 (n = 70 por grupo) modelos de gesso, sendo observada a precisão angular de três sulcos (20 µm, 50 µm e 75 µm) para cada período. A precisão da reprodução de detalhes foi classificada usando uma classificação de pontuação predeterminada. As medições das mudanças dimensionais foram feitas no programa Corel DRAW X6. Os dados foram submetidos ao teste t de Student (α = 0,05). Resultados: Foi observada diferença estatística em relação à matriz após 24h para ambos os alginatos. Uma mudança dimensional linear negativa estatisticamente significativa (contração) foi verificada após 24 h de armazenamento (1,52% para alginato de alta estabilidade; 1,32% para alginato convencional). O alginato de alta estabilidade manteve os detalhes completos por até 72 horas, enquanto o alginato convencional, por 24 horas. Os alginatos reproduziram o sulco de 75 µm para todos os períodos. Conclusão: As impressões feitas com ambos os alginatos devem ser imediatamente vazadas para se ter resultados clínicos satisfatórios.

PURPOSE: To assess the absolute linear distances of three different intraoral scan bodies (ISBs) using an intraoral scanner compared to a conventional impression in a common clinical model setup with a gap and a free-end situation in the maxilla. MATERIALS AND METHODS: An implant master model with a reference cube was digitized using x-ray computed tomography and served as the reference file. Digital impressions (TRIOS, 3Shape) were taken using three different ISB manufacturers: NT Trading, Kulzer, and Medentika (n = 10 per group). Conventional implant impressions were taken for comparison (n = 10). The conventional models were digitized, and all models (digital and conventional) were superimposed with the reference file to obtain the 3D deviations for the implant-abutment-interface points (IAIPs). Results for linear deviation (trueness and precision) were analyzed using pairwise comparisons (P < .05; SPSS version 25). For precision, a two-way factorial mixed ANOVA was used. RESULTS: The deviations for trueness (mean) ± precision (SD) of the IAIPs ranged as follows: FDI region 14 = 0.106 ± 0.050 mm (Medentika) to 0.134 ± .026 mm (NT Trading); region 16 = 0.108 ± 0.046 mm (conventional) to 0.164 ± 0.032 mm (NT Trading); region 24 = 0.111 ± 0.050 mm (conventional) to 0.191 ± 0.052 mm (Medentika); region 26 = 0.086 ± 0.040 mm (conventional) to 0.199 ± 0.066 mm (Kulzer). There were significant differences for trueness between all digital and conventional impression techniques. For precision, only two significant differences in two implant regions (14, 24) were observed. CONCLUSION: Longer scanning paths resulted in higher deviations of the implant position in digital impressions. Due to algorithms implemented in the software, errors resulting from the different scan bodies may be reduced during the alignment process of the IOS in clinical practice.

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.

The aim of this study was to verify the effectiveness of alternative techniques for measuring the linear dimensional change of molds obtained by different impression materials. A stainless-steel die containing three lines was used to get the impressions. The impression materials were handled according to the manufacturers' instructions. After gelation/polymerization time, the molds (n=12) were stored for 30 minutes and the lines were subsequently measured using: a microscope (Olympus Measuring Microscope STM; Olympus Optical Co) with a 30x magnification (MM, control group), a digital caliper (Mitutoyo Digimatic; Kawasaki) (DC) and digitization using a digital camera (Canon EOS Rebel 3Ti; Canon) (DI). For each mold, a mean of the length of the lines was obtained. For each impression material, the difference in the length between the metallic matrix and the mold was considered as linear dimensional change (%). The data were submitted to the non-parametric Kolmogorov-Smirnov test, followed by one-way Analysis of Variance (ANOVA) for each material, and the means were compared by the Tukey test (α=0.05). The DI group promoted values of dimensional accuracy without significant differences with the control group (MM), except for the putty-body condensation silicone. The DC group showed significant differences for MM and DI groups for all impression materials tested. The DI group showed to be a reliable methodology (Standard error of the mean

Statement of problem The dimensional stability of alginate dental impressions is a key factor for the reliability of delayed gypsum pouring and digital scanning. However, studies of the dimensional stability of alginates with conventional methods that consider the dimensional variations of large impressions are lacking. Purpose The purpose of this in vitro study was to investigate and compare 2 digital methods for the analysis of dimensional stability of large impressions made with 5 different extended-pour alginates and to assess dimensional stability up to 5 days. Material and methods Impressions of a simplified master maxillary model were made with Alginoplast, Blueprint, Hydrogum 5, Orthoprint, and Phase Plus and then analyzed at different time points. Digital scans of the alginate impression surfaces were obtained with a desktop scanner and analyzed by evaluating the linear measurements between reference points and by using a novel method that consists of the analysis of the entire scanned surface to evaluate the expansion and contraction of the impressions. Results The first method revealed that the dimensional changes did not exceed 0.5%, with the exception of Phase Plus at day 3 (-0.6 ±0.7%), and the average dimensional variation was always lower than or equal to 0.2 mm. Blueprint was the most stable material (-0.2 ±0.6%). The second method revealed dimensional variations always lower than 0.03 mm and confirmed Blueprint as the best performing material (0.001 ±0.006 mm) and Phase Plus the worst (-0.019 ±0.006 mm). Conclusions Both the methods used to evaluate alginate stability showed that the analyzed materials remain stable over time; the dimensional variations showed a similar trend, with differences in the absolute values depending on the applied method. Linear measurements are affected by the operator and choice of reference points; however, by evaluating the average variations of the entire structure surfaces, local variations should be minimized. The evaluation of the average variations with the second method offers the advantage of a rapid visual representation of these variations.

Aim and Objective. Impression materials and stone casts are the main sources of cross-contamination and transmission of dental infections between dental offices and laboratories. Both Surfosept (alcohol-based) and Deconex® (quaternary ammonium compound) are biocompatible solutions that have superior antimicrobial properties against bacteria, fungi, and viral envelope. Considering the influence of disinfection substances on the dimensions of impression materials, this study aimed to compare the effect of Surfosept and Deconex® 53 on the accuracy and dimensional stability of the Panasil® dental addition silicone material. Materials and Methods. This in vitro study was performed on 30 dental casts. The samples were divided into one control group and two experimental groups to be disinfected with Surfosept (1%) and Deconex® 53 (2%) using a sequential sampling method (10 per group). The impressions in the experimental groups (i.e., Surfosept and Deconex® 53) were rinsed and dried; then, the disinfectant was sprayed on the impressions and remained for 30 seconds before pouring with stone. In the control group, the impressions were only rinsed and dried and were poured in 10 minutes. Cast dimensions were measured by a profile projector device, and the mean values obtained from the experimental groups were compared with those of the control group. Results. There were no significant differences among the groups regarding the height of the resulting dies without undercut ( P = 0.62 ). Moreover, there was no significant difference among the groups regarding the distance between the two dies ( P = 0.77 ). However, the diameter of the dies with undercut and without undercut was different significantly among the control and experimental groups ( P < 0.005 ). Conclusion. In general, no significant difference was encountered between dimensional stability and accuracy of the dental impressions using Surfosept and Deconex® 53 in this study.

Source of funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectorsType of study/design Randomised controlled trial (RCT) with parallel design.Subjects This RCT was conducted at the Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Centre of Dental Medicine, University of Zurich, Zurich, Switzerland. Ten patients, six women and four men, with a mean age of 62 years and an age range of 49-77 years, requiring posterior tooth-supported 3-unit fixed partial dentures (FPDs) were included in this RCT. The abutment teeth were six molars and six premolars in the maxilla and five molars and three premolars in the mandible. The patients fulfilled the following inclusion criteria: they all were >18 years, with a full mouth plaque score

Objectives To study the effects of incorporating a further crosslinking agent and a novel surfactant on the water absorption behaviour of experimental VPS impression materials. Methods Part 1: The water uptake behaviour of Aquasil-Ultra-Monophase (AqM) was studied gravimetrically in three media (DW, 1%NaOCl and Perform ID), at 23 °C and 37 °C, over a period of one and four-months (n = 5) to gain information on long-term immersion. Part 2: Five experimental materials were formulated: Exp-I and II as hydrophobic and Exp-III-V as hydrophilic, containing an additional cross-linking agent (TFDMSOS) and Rhodasurf CET-2 surfactant. Their water uptake and desorption (both at 23 °C) properties (gravemetrically), solubility, pH and diffusion coefficient (DC) data were compared with three commercial, hydrophilic VPS impression materials, over seven days (n = 5). The results were analysed statistically. Results Part 1: Significant differences in water absorbed by AqM were observed in the three media at 23 °C. Aq M had a significantly higher uptake in 2% Perform ID, than in DW and NaOCl. At 37 °C, over four-months the uptake profiles were more enhanced and differed. Part 2: All Exp and commercial materials significantly increased in weight in both media (DW and 1% NaOCl at 23 °C), with differing uptake profiles and non-reached equilibrium. Exp-VPS absorbed significantly less water than commercial-VPS. Desorption of all VPS from both parts was faster than absorption, followed Fickian diffusion kinetics and reached equilibrium within 1–3 days. Desorption DCs for Exp-VPS were higher than commercial materials (10−10 versus 10−11 m2 s−1). The solubility was higher in 1% NaOCl compared to DW. The pH of DW after immersion of samples significantly increased compared to 1% NaOCl. Significance The incorporation of novel cross-linking agent, TFDMSOS and non-ionic surfactant, Rhodasurf CET-2, (ethoxylated-cetyl-oleyl alcohol) improved the dimensional stability of hydrophilic Exp-VPS in DW and 1% NaOCl. These materials merit further research in producing accurate casts of the patient’s anatomy following disinfection.