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Journal of Prosthodontics : Official... Feb 2021The accuracy of digital impressions is still controversial for complete arch implant cases. The aim of this study is to compare the accuracy of different intraoral...
PURPOSE
The accuracy of digital impressions is still controversial for complete arch implant cases. The aim of this study is to compare the accuracy of different intraoral scanners with the conventional technique in terms of trueness and precision in a complete arch implant model.
MATERIAL AND METHODS
Eight implants were inserted asymmetrically in a polyurethane edentulous mandibular model with different angulations. A 3-dimensional (3D) reference model was obtained by scanning this polyurethane model with an optical scanner. First, digital impressions were made by using 3 different intraoral scanners: Carestream 3500 (DC), Cerec Omnicam (DO) and 3Shape Trios 3 (DT). Subsequently, a nonsplinted open tray impression technique was used for conventional impression group (C) and then the master casts were digitalized with a lab scanner. Each 10 STL files belonging to 4 different impression groups were imported to a reverse engineering program, to measure distance and angle deviations from the reference model. All statistical analyses were performed after taking absolute values of the data. After comparing the impression groups with one-way ANOVA, the trueness and precision values were analyzed by Tukey post hoc test and 0.05 was used as the level of significance.
RESULTS
The mean trueness of distance was 123.06 ± 89.83 µm for DC, 229.72 ± 121.34 µm for DO, 209.75 ± 47.07 µm for DT, and 345.32 ± 75.12 µm for C group (p < 0.0001). While DC showed significantly lower deviation compared to DO and C, no significant difference was found between DC and DT. C showed the highest distance deviation significantly in all groups; and no significant difference was found between DO and DT groups. In angle measurements; the trueness was 0.26° ± 0.07° for DC, 0.53° ± 0.42° for DO, 0.33° ± 0.30° for DT, and 0.74° ± 0.65° for C group. There was no significant difference between the groups in terms of angular trueness (p = 0.074). In terms of the precision for distance, the results of DC 80.43 ± 29.69 µm, DO 94.06 ± 69.96 µm, DT 35.55 ± 28.46 µm and C 66.97 ± 36.69 µm were determined (p = 0.036). The significant difference was found only between DT and DO among all groups. Finally, angular precision was determined to be 0.19° ± 0.11° for DC, 0.30° ± 0.28° for DO, 0.22° ± 0.19° for DT, and 0.50° ± 0.38° for Group C. No significant difference was found between the groups, in terms of angular precision (p = 0.053).
CONCLUSIONS
All digital impression groups yielded superior data compared to conventional technique in terms of trueness. DC formed the impression group with the highest trueness in both distance and angular measurements. The results of this in vitro study suggest the use of intraoral scanners compared to the conventional impression techniques in complete arch implant cases with high angulations.
Topics: Computer-Aided Design; Dental Arch; Dental Implants; Dental Impression Technique; Imaging, Three-Dimensional; Models, Dental
PubMed: 32935894
DOI: 10.1111/jopr.13264 -
The Journal of Prosthetic Dentistry Dec 2021New polyvinyl siloxane (PVS) materials with enhanced properties have been developed to improve and facilitate implant impression techniques. However, studies on their...
STATEMENT OF PROBLEM
New polyvinyl siloxane (PVS) materials with enhanced properties have been developed to improve and facilitate implant impression techniques. However, studies on their accuracy are lacking.
PURPOSE
The purpose of this in vitro study was to determine the accuracy and precision of implant impressions made with some recently introduced materials on a simulated patient requiring an all-on-4 implant-supported prosthesis. Well-established polyether materials were also evaluated as a comparison. The variables considered were material type, consistency, splinting or not splinting techniques, and implant angulation.
MATERIAL AND METHODS
A reference master model was made by inserting 4 implants at angles of 0, 5, and 10 degrees. Eighty impressions were made at 37 °C in wet conditions by using a standardized technique. Eight groups (n=10) were created using monophasic, single-viscosity materials (Hydrorise Implant Medium, HIM-ns; Hydrorise Implant Medium, HIM; Honigum Mono, HM; Impregum, IMP), and 2-viscosity materials (Hydrorise Implant Heavy+Light-ns, HIH+L-ns; Hydrorise Implant Heavy+Light, HIH+L; Honigum Heavy+Light, HH+L; and Permadyne and Garant [Heavy+Light, PeH+L]). Hydrorise materials were used with splinting and not splinting (ns) techniques. The reference points located on the connecting platforms of the transfer copings (TCP) were compared with the same points on the implant connecting platforms (ICP) located in the reference model. The accuracy and precision of the impressions were determined as linear 3D errors and standard deviation between each TCP-ICP couple by using an optical coordinate measuring machine (OCMM).
RESULTS
PVS materials were generally better than polyether materials, with Hydrorise materials (HIM and HIH+L) showing significantly better accuracy and precision (30.9 ±14.4 μm and 28.7 ±15.5 μm, respectively) than IMP and PeH+L polyethers (44.2 ±16 μm and 43.8 ±17.6 μm, respectively; P<.001). Honigum materials were statistically similar to Hydrorise materials (P=.765). The values shown by Hydrorise nonsplinted groups (HIH+L-ns and HIM-ns) were not statistically different from those of the splinted polyether impressions (P=.386). The viscosities (monophasic or heavy+light) had no effect on accuracy, but monophasic material positively influenced precision (HIM and HIH+L, P=.001). No correlation was found between implant angulation and accuracy (multilevel analysis and Kendall rank correlation coefficient=-0.065; P=.133).
CONCLUSIONS
Recently introduced materials designed for implant impressions showed significantly higher accuracy and precision; even with the unfavorable nonsplinting technique, the new materials performed similarly to, or better than, polyether materials. Although the transfer coping splinting technique generally improved the accuracy and precision of Hydrorise materials, the effect was significant only within HIH+L groups.
Topics: Dental Implants; Dental Impression Materials; Dental Impression Technique; Humans; Models, Dental
PubMed: 33526247
DOI: 10.1016/j.prosdent.2020.10.017 -
The Journal of Prosthetic Dentistry Dec 2022Making conventional facial impressions can be uncomfortable for the patient and complicated for the prosthodontist. Using facial scanners to digitize faces is an...
STATEMENT OF PROBLEM
Making conventional facial impressions can be uncomfortable for the patient and complicated for the prosthodontist. Using facial scanners to digitize faces is an alternative approach. However, the initial costs of the equipment have prevented their widespread use in dental practice, and the accuracy of ear scanning is unclear.
PURPOSE
The purpose of this in vitro study was to investigate the accuracy of a widely used intraoral scanner for digitizing an ear model.
MATERIAL AND METHODS
For reference, a silicone model of an ear was scanned with an industrial scanner. Then, the model was scanned 5 times with an intraoral scanner. Five conventional impressions of the model were made with a hydrocolloid impression material and poured with dental stone. The stone casts were then digitized with a desktop scanner. The data sets acquired with the 3 approaches were analyzed by using a 3-dimensional (3D) evaluation software program. Trueness and precision values were calculated for each approach. Linear mixed models with random intercepts were fitted to each sample to evaluate the effects of the impression method on mean deviations (α=.05).
RESULTS
Mean ±standard deviation trueness and precision values were 0.097 ±0.012 mm and 0.033 ±0.015 mm, respectively, for the digital scan, and 0.092 ±0.022 mm and 0.081 ±0.024 mm for the conventional impression, showing a significantly lower deviation in precision for the digital approach (P<.001).
CONCLUSIONS
The feasibility of digitizing an ear efficiently by using the investigated intraoral scanner was demonstrated, and similar trueness and significantly better precision values were achieved than when using conventional impressions. These promising results suggest the need for clinical investigations.
PubMed: 36586814
DOI: 10.1016/j.prosdent.2022.11.010 -
Frontiers in Dentistry 2021Intraoral scanners have shown promising results when used as an adjunct or alternative to conventional impression techniques. This study compared the accuracy of...
Intraoral scanners have shown promising results when used as an adjunct or alternative to conventional impression techniques. This study compared the accuracy of digital impression taking using an intraoral scanner versus the conventional technique. In this in-vitro experimental study, a typodont molar tooth was prepared as the standard model and scanned by TRIOS intraoral scanner. Ten digital impressions were fabricated as such and intraoral scans were sent to the manufacturers. In the conventional method, using addition silicone impression material, a stone die was fabricated. Using a computer-aided design/computer-aided manufacturing scanner, the die was scanned, and the data were transferred to the software. After the fabrication of frameworks, the replica technique was used. The replicas' thickness (indicative of the gap between the framework and the model and the accuracy of impression taking) was 12 points. The data were analyzed using student's t-test. The mean thickness of replicas (gap between the internal surface of frameworks and the standard model) at the three points in the buccal, lingual, mesial, and distal sections in the digital impression technique was lower than that in the conventional technique (P<0.0001). In other words, the accuracy of impressions taken by the digital method was significantly higher than those taken by the conventional method. Intraoral digital scanner had significantly higher accuracy than the conventional method in all points. Thus, the digital method can be reliably used as an adjunct or alternative to the conventional method to increase the accuracy of impression taking.
PubMed: 35965710
DOI: 10.18502/fid.v18i6.5649 -
Journal of Biological Regulators and... 2021For dental impression of a prepared tooth, the goal is a void-free negative representation from which an accurate cast of a tooth and its surrounding tissue can be...
For dental impression of a prepared tooth, the goal is a void-free negative representation from which an accurate cast of a tooth and its surrounding tissue can be reproduced. This in-vitro study assessed and compared the reproduction accuracies of surface detail obtained with three different dental elastomeric impression materials: vinyl polysiloxane (VPS), vinyl polyether silicone (VPES), and polyether (PE). A stainless-steel model with two abutments was used, with impressions taken 10 times for each material, for 20 abutment impressions per group, using a two-phase, one-step technique (heavy body/light body). The impressions were removed and assessed for numbers of enclosed voids and open voids visible on the surface. The defect frequency was 95% for impressions with the VPS and VPES materials, and 30% for the PE material. No significant differences were seen for number of impressions with defects for VPS versus VPES. Significant differences were seen for VPS and VPES versus the PE material (P <.05). No significant differences were seen for the defect type distributions across these three impression materials. The PE impression material showed better accuracy for reproduction of surface detail of these dental impressions compared to the VPS and VPES impression materials.
Topics: Dental Impression Materials; Dental Impression Technique; Materials Testing; Models, Dental; Reproducibility of Results; Surface Properties
PubMed: 33435664
DOI: 10.23812/20-561-A -
BMC Research Notes Jun 2022Since there is no material in the market met all the ideal requirements of an impression material, thus in an attempt to find one, hybridization between the two most...
OBJECTIVE
Since there is no material in the market met all the ideal requirements of an impression material, thus in an attempt to find one, hybridization between the two most commonly used impression materials were done. The aim of the hybridization was to obtain a new material combining the good merits of both and eliminate their shortcomings. Thus, this study aimed to assess the impact of hybridization between polyether with addition silicone on tear strength and elastic recovery of the new material and compare such effect with regard to parent materials.
RESULTS
A polyether (PE), polyvinyl siloxanse (PVS) and vinyl polyether silicone (VPES) hybrid elastomers were used in the present study. Tear strength was measured one hour after setting time of each material according to the manufacturer and the three materials showed statistically comparable tear strength in N/mm. Elastic recovery was evaluated one minute after the setting time recommended by the manufacturer. The three materials were statistically insignificant from each other, and all met the ISO4823 requirement of having greater than 96.5% recovery.
Topics: Dental Impression Materials; Elasticity; Materials Testing; Polyvinyls; Resins, Synthetic; Silicone Elastomers; Surface Properties
PubMed: 35761301
DOI: 10.1186/s13104-022-06110-3 -
The Journal of Prosthetic Dentistry Oct 2022The technology behind optical scanners has greatly improved recently, making their dental application advantageous. While their accuracy is now comparable with that of... (Meta-Analysis)
Meta-Analysis Review
Patient preference and clinical working time between digital scanning and conventional impression making for implant-supported prostheses: A systematic review and meta-analysis.
STATEMENT OF PROBLEM
The technology behind optical scanners has greatly improved recently, making their dental application advantageous. While their accuracy is now comparable with that of conventional impression materials, whether these techniques have other advantages is unclear.
PURPOSE
The purpose of this systematic review and meta-analysis was to determine whether digital scanning for implant-supported restorations is more time-efficient and convenient for the patient.
MATERIAL AND METHODS
The study was conducted on September 23, 2020 using 4 different databases (Medline, Cochrane, Web of Science, Scopus) searching for clinical studies that compared the time needed and/or patient perceptions between those who had undergone the digital scanning procedure and those who had undergone conventional impression making.
RESULTS
Twelve studies met the inclusion criteria for qualitative and quantitative analysis. Outcome variables were measured as standard mean differences (SMDs) by following a fixed-effects model or random-effects model (in the case of high heterogeneity). Digital scanning was more time-efficient and was preferred by patients for all 4 analyzed outcomes (comfort, anxiety, nausea, time perception).
CONCLUSIONS
Digital scanning was found to be more time-efficient and convenient than conventional impression making for implant-supported restorations. Additional randomized controlled trials are needed to confirm the findings of this review.
Topics: Humans; Dental Impression Technique; Computer-Aided Design; Patient Preference; Dental Implants; Dental Impression Materials
PubMed: 33678434
DOI: 10.1016/j.prosdent.2020.11.042 -
Minerva Stomatologica Apr 2020Alginic acid is a polysaccharide widely present in the cellular walls of brown algae. Alginate is widely used as a mold material in dentistry, in the production of... (Review)
Review
Alginic acid is a polysaccharide widely present in the cellular walls of brown algae. Alginate is widely used as a mold material in dentistry, in the production of prostheses and in the production of positives for small-scale casting. It is also used in the pharmaceutical, cosmetic and food industries for various uses. The purpose of our study is to assess whether the chemical and physical characteristics of water can influence the characteristics and performance of these materials. These impression materials are often marketed as a powder to be mixed with water, but water is not included during the purchase. We have considered different articles, but unfortunately the results that speak of this topic are few and contain little information. We have therefore carried out a review of the present literature on Pubmed and Embase search engine. The same product used by two people with two different waters will have different characteristics. The possibility of knowing these effects could allow for more performing materials and above all for identical and reproducible materials. In conclusions, the results indicate to follow the manufacturer's instructions, and eventually turn to the use of automatic devices.
Topics: Alginates; Dental Impression Materials; Materials Testing; Powders
PubMed: 32489090
DOI: 10.23736/S0026-4970.19.04293-6 -
Journal of Dental Sciences Apr 2023An understanding of self-protection related factors is important for dental infection control. This study aimed to investigate factors associated with personal...
BACKGROUND/PURPOSE
An understanding of self-protection related factors is important for dental infection control. This study aimed to investigate factors associated with personal self-protection in infection control among dental care workers.
MATERIALS AND METHODS
A cross-sectional survey with self-report questionnaire was conducted between Jan and Dec, 2018.275 dentists and 298 dental assistants were enrolled from randomly selected dental care settings.
RESULTS
Compliance with wearing hair caps, facial masks, and hand washing is not as high as oral masks and gloves (over 90%). For dentists, the level of clinical setting (aOR = 3.1, < 0.001) and the correct use of disinfectants for impression materials (aOR = 2.0, < 0.05) were associated with hair cap wearing. Gender (aOR = 0.15, < 0.05) and correct use of indicator during sterilization (aOR = 2.9, < 0.05) were associated with facial mask wearing. The correct use of indicator during sterilization (aOR = 2.4, < 0.05) and disinfection for impression materials (aOR = 2.2, < 0.05) were associated with hand washing. For dental assistants, longer work experience (aOR = 1.05, < 0.05), working days (aOR = 1.82, < 0.05), the correct use of disinfectants for impression materials (aOR = 2.4, < 0.001), and the frequent use of gloves (aOR = 8.0, < 0.05) were associated with facial mask wearing. The surface disinfection of working tables (aOR = 2.8, < 0.001) and the frequent changing of gloves (aOR = 5.96, < 0.05) were associated with hand washing.
CONCLUSION
Gender, the length of work practice, and correct techniques for sterilization use were identified as major factors associated with compliance with self-protection in infection control among dental care workers.
PubMed: 37021205
DOI: 10.1016/j.jds.2022.11.023 -
The Saudi Dental Journal May 2020The objective of this systematic review and meta-analysis study was to identify the different disinfection methods and materials and the existing evidence on their... (Review)
Review
Effect of chemical, microwave irradiation, steam autoclave, ultraviolet light radiation, ozone and electrolyzed oxidizing water disinfection on properties of impression materials: A systematic review and meta-analysis study.
OBJECTIVES
The objective of this systematic review and meta-analysis study was to identify the different disinfection methods and materials and the existing evidence on their effect on properties of the different impression materials.
MATERIAL AND METHODS
An electronic search of MEDLINE (PubMed), Science Direct, and Google Scholar databases was performed to retrieve related English-language articles published between January 2000 and July 2019. Available studies with search terms such as: Impression disinfection, disinfection method, impression dimensional stability and impression wettability were used. The selected articles were reviewed by screening their titles and abstracts and full text. Finally, a total of 70 articles were considered relevant and were included in this study.
RESULTS
Extensive studies were conducted to determine the effect of the different disinfection methods and materials on the properties of the different impression materials such as dimensional stability, wettability and surface roughness. While some studies reported significant changes in the properties of the impression materials, others reported either no changes or minor insignificant effects.
CONCLUSIONS
Some studies reported significant changes in the properties of the impression materials as a result of using different disinfection methods, whereas others reported either minor insignificant or no changes. Although the findings of the studies were controversial, care should be taken to avoid distortion of impressions and loss of their surface details that can adversely affect the fitting accuracy of the restorations. Therefore, better designed and standardized studies are needed to evaluate the effect of different commonly used disinfectants on properties of impression materials. Moreover, manufacturers should be encouraged to recommend specific disinfection methods and materials for disinfecting the impression materials to ensure their optimal accuracy.
PubMed: 32405219
DOI: 10.1016/j.sdentj.2019.12.003