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Journal of Oral Science Dec 2017The aim of this study was to examine the effects of tray design and impression material on impression pressure in a clinical simulation model of an edentulous mandible....
The aim of this study was to examine the effects of tray design and impression material on impression pressure in a clinical simulation model of an edentulous mandible. Two types of polyvinylsiloxane elastomer, one type of polyether elastomer, and one type of alginate were used. The three tray types had no relief, 0.36 mm of relief, or 1.4 mm of relief, with or without escape holes. Impression pressure was measured at the median alveolar crest, the bilateral alveolar crests corresponding to molars, and the bilateral buccal shelves. Impression pressure significantly differed in relation to tray design and sensor position. In trays without escape holes, impression pressure was highest at the median alveolar crest and lowest at the buccal shelves, for all impression materials. However, impression material had no significant effects on impression pressure. Our results suggest that bite-pressure load on alveolar crests can be alleviated by making an impression with a tray that has relief and escape holes, while applying pressure to buccal shelves and almost no pressure to alveolar crests.
Topics: Alginates; Alveolar Process; Dental Impression Materials; Dental Impression Technique; Glucuronic Acid; Hexuronic Acids; Humans; Jaw, Edentulous; Mandible; Maxilla; Polyvinyls; Pressure; Siloxanes
PubMed: 28855443
DOI: 10.2334/josnusd.16-0731 -
Dental and Medical Problems 2021Making accurate impressions of dental implants and transferring their three-dimensional (3D) position to master casts is critical for the passive fit of prosthetic...
BACKGROUND
Making accurate impressions of dental implants and transferring their three-dimensional (3D) position to master casts is critical for the passive fit of prosthetic frameworks.
OBJECTIVES
This study aimed to assess the effect of dental implant angulation on the dimensional accuracy of master casts.
MATERIAL AND METHODS
An acrylic model with 2 external hexagonal implants was used in this in vitro experimental study. The impressions of the model were made in 42 positions, with different angulation of the 2 implants, ranging from +15° to -15°, by means of the open-tray and closed-tray impression techniques, using a polyvinyl siloxane impression material. The spatial coordinates of the implants were measured on the X, Y and Z axes. The dimensional accuracy of the impressions made at different positions (parallel, convergent and divergent) and different angulation of the implants were determined. The data was analyzed using the one-way analysis of variance (ANOVA), Student's t test and Tukey's test.
RESULTS
Casts with the lowest accuracy were obtained when the 2 implants were divergent by 25° (R = 1.1336). However, the position of the 2 implants had no significant effect on the dimensional accuracy of the master casts. The error rate was 0.4181 in the open-tray technique and 0.5095 in the closed-tray technique, with no significant difference between them (p > 0.05). The angulation of the 2 implants had a significant effect on the dimensional accuracy of the master casts (p = 0.0001).
CONCLUSIONS
Considering the significant effect of implant angulation in the range from +15° to -15° relative to the longitudinal axis on the dimensional accuracy of master casts, further studies are required to reach a final conclusion in this respect.
Topics: Dental Implants; Dental Impression Materials; Dental Impression Technique; Humans; Models, Dental
PubMed: 34994115
DOI: 10.17219/dmp/133894 -
Journal of Radiation Research Sep 2022We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and...
We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and dental impression materials. The present investigation demonstrated that with this system, the changes in the absorbed dose to water depending on the material of the mouthpiece were small, with a maximum of 0.32% for a 10-MV photon beam. For the dental impression material, we selected a silicone material with the lowest Hounsfield unit (HU) value that had little effect on the generation of artifacts and the quality of the X-ray beam. Multiphase magnetic resonance imaging (MRI) revealed that the head-up and -down motions in the thermoplastic shell without the mouthpiece were 5.76 ± 1.54 mm, whereas the motion with the mouthpiece decreased significantly to 1.72 ± 0.92 mm (P = 0.006). Similarly, the head-left and -right motion displacement decreased from 6.32 ± 1.86 mm without the mouthpiece to 1.80 ± 0.42 mm with the mouthpiece (P = 0.003). Regarding the tongue depressor function of the mouthpiece, the median distance from the hard palate to the surface of the tongue was 28.42 mm. The present results indicate that the new immobilization device developed herein that uses a mouthpiece and a thermoplastic shell is useful for suppressing patients' head motions and tongue positions.
Topics: Dental Impression Materials; Head and Neck Neoplasms; Humans; Neck; Radiotherapy Planning, Computer-Assisted; Silicones; Water
PubMed: 35818301
DOI: 10.1093/jrr/rrac044 -
Journal of Indian Prosthodontic Society 2017A dental impression is a negative imprint of an oral structure that can be used to produce a positive cast of a patient's teeth as a permanent record. The accuracy of...
INTRODUCTION
A dental impression is a negative imprint of an oral structure that can be used to produce a positive cast of a patient's teeth as a permanent record. The accuracy of the impression affects the accuracy of the cast, and a precise impression is needed in order to create prosthesis with optimal fitting. Minimization of misfit is an important aim in prosthesis science and dental implants. The aim of this study was to evaluate the effects of the materials and techniques used to take an impression on the vertical misfit of implant-supported, screw-retained, three-unit bridges.
MATERIALS AND METHODS
The principal model used was an acrylic block with two ITI implants. A 1.5-mm abutment was attached to fixtures with torque of 25 N.cm. A base-metal framework was built on the abutment in the acrylic block. The abutments of the acrylic model were unscrewed and fixture-level impressions were made. The impression techniques included open/closed-tray techniques and the impression materials were polyether and polyvinyl siloxane. Forty acrylic custom trays were built for each impression. The marginal gap in the framework at three points (buccal, lingual, and distal) was measured using an optical microscope with ×250.
RESULTS
It is demonstrated that in all 360 evaluated samples, the mean vertical misfit in polyether samples of molar and premolar teeth was significantly lower than in polyvinyl siloxane ( < 0.001 and = 0.017, respectively) in all three locations of the molar and lingual premolar examined (buccal, lingual, and distal), the mean vertical misfit of the polyether samples was significantly lower than those of polyvinyl siloxane ( < 0.01). On the other hand, although the mean vertical misfit using the open-tray technique in the molar teeth was significantly lower than with the closed-tray method ( = 0.002), no statistical difference was seen between the open-tray and closed-tray technique in general ( = 0.87).
CONCLUSION
Within the limitations of this study, the following conclusions can be drawn: The impression method had no effect on marginal discrepancy of 3-unit screw retained fixed partial dentures. A higher marginal accuracy was obtained using polyether impression material compared to polyvinyl siloxane.
PubMed: 28216844
DOI: 10.4103/0972-4052.197937 -
BMC Oral Health Jul 2023Polyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better... (Meta-Analysis)
Meta-Analysis
BACKGROUND AND OBJECTIVES
Polyvinyl ether siloxane (PVES) possesses ideal characteristics for making precise and accurate dental impressions. PVES dimensional stability owes to its better polymeric properties derived from its parent materials poly ethers and polyvinyl siloxanes. As recommended use of chemical disinfecting agents is getting more popular, there is a growing concern associated with the effect of disinfectants on PVES dimensional stability. This study was aimed to understand the PVES behavior when subjected to chemical disinfectants.
MATERIALS AND METHODOLOGY
The data was collected from research studies retrieved from Google Scholar, Scopus, and PubMed using MeSH terms of keywords "vinyl polyether siloxane AND Disinfection" or (Vinyl polyether siloxane OR polyvinyl siloxane ether OR PVES) AND (disinfectant OR disinfection)" without any restriction to publication date. The PRISMA (Preferred Reporting Items for Systemic Review and Meta-Analysis) directions were observed during the data collection, screening of studies, and meta-analysis. The primary data were retrieved, and batch exported from databases using Harzing's Publish or Perish software; primary analysis was performed in Microsoft Excel, while statistical analysis for effect size, two-tailed p-values, and heterogeneity among studies was performed using Meta Essentials. The effect size was calculated using Hedge's g values at the 95% confidence level using the random-effects model. Heterogeneity among studies was measured using the Cochrane Q and I.
RESULTS AND CONCLUSION
Dental impressions made from the PVES elastomeric impression materials showed no significant changes in dimensional stability. Immersion in the chemical disinfectant for 10 min was associated with clinically irrelevant changes in the dimensions of the PVES impressions. Disinfection with sodium hypochlorite was associated with clinically significant changes in dimensions, with a two-tailed p-value of 0.049. Disinfection with 2-2.5% glutaraldehyde solution was not associated with any significant dimensional variability.
Topics: Humans; Disinfectants; Disinfection; Ether; Ethers; Ethyl Ethers; Polyvinyls; Siloxanes
PubMed: 37430254
DOI: 10.1186/s12903-023-03168-8 -
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 -
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 -
Materials (Basel, Switzerland) Nov 2022In the intraoral scanner (IOS) impression technique for dental implants, a scanbody (SB) is connected to the implant and scanned. Poly(ether-ether-ketone) (PEEK) is a...
In the intraoral scanner (IOS) impression technique for dental implants, a scanbody (SB) is connected to the implant and scanned. Poly(ether-ether-ketone) (PEEK) is a widely used material for SBs and it is recommended for single use. However, from the perspective of the Sustainable Development Goals, it is desirable to use these products multiple times. As SBs are used in patients' mouths, proper sterilization is necessary for multiple uses. In the present study, the effect of autoclave treatment and connection/disconnection on SB deformation was investigated. The SB was connected to the implant and stereolithography (STL) data were obtained. Then, the SB was disconnected and underwent autoclave treatment, or was connected and disconnected multiple times, or underwent a combination of both processes. The results showed that there were significant differences in the distance and angle when comparing SBs before and after the autoclave treatment, but repeated connections with or without autoclave treatment had no significant impact on the measured values. The surface texture, observed with scanning electron microscopy, showed that a groove was observed on the surface of the SB, but the groove did not show major changes after 10 connection/autoclave processes. These results indicate that autoclave sterilization has some impact on SB deformation but connection/disconnection itself may not have a huge impact on SB deformation.
PubMed: 36363311
DOI: 10.3390/ma15217717 -
Journal of Pharmacy & Bioallied Sciences Jul 2023The current study examined the accuracy of casts generated using direct impression processes with and without splints for multiple dental implants utilizing two...
A Comparative Study to Assess Accuracy of Casts Prepared using Direct Impression Technique with and without Splinting of Multiple Dental Implants Utilising Two Different Splinting and Impression Materials.
BACKGROUND
The current study examined the accuracy of casts generated using direct impression processes with and without splints for multiple dental implants utilizing two different splinting materials and impression materials.
MATERIALS AND METHODS
Dental replacement base intensity alleviating acrylic tar was used to create a reference model of a mandible with four inserts (Uniti, Equinox, D-3.7 mm, and L-13 mm) in the front. Polyether and polyvinyle siloxane impression materials were used to make impressions of the reference model utilizing direct non-splinted and splinted techniques.
RESULTS
Polyether impression material was found to produce more accurate impressions than polyvinyl siloxane, and impressions made using transfer copings splinted with pattern resins were found to be more accurate than those made using either unsplinted copings or copings splinted with light-cured wax resin.
CONCLUSIONS
All six impression techniques resulted in casts that were different from the reference model. Next, the polyether-splinted (SPR) technique is the nonsplinted technique employing polyether and polyvinyle siloxane imprint materials, and then, the splinted techniques using polyether and polyvinyle siloxane and produced the most accurate casts in comparison with the reference model.
PubMed: 37694030
DOI: 10.4103/jpbs.jpbs_271_23 -
BioMed Research International 2019Recent data indicates limited awareness and compliance on infection prevention procedures by dental offices and by dental laboratories. Guidelines for infection... (Review)
Review
Recent data indicates limited awareness and compliance on infection prevention procedures by dental offices and by dental laboratories. Guidelines for infection prevention in dentistry have been published by Centres for Disease Control and Prevention since 2003; the section "IX-Special consideration" includes a subsection concerning the prevention in dental laboratories, but it has not been modernised in later versions to fit the needs of traditional and computer-aided technology. Traditional techniques required disinfecting items (impression, chewing waxes, and appliances) with well-suited products, which are also chosen for limiting impression changes or appliance deterioration. Effective procedures are available with difficulties. Some of these contain irritant or non-eco-friendly disinfectants. The transport of impression, to dental laboratories, is often delayed with limited precautions for limiting cross-infection. Gypsum casts are frequently contaminated mainly by bacteria and their antibiotic-resistant strains and even stored for long periods during dental implant supported restoration and orthodontic therapy, becoming a hidden source of infection. Nowadays, computer-aided design/computer-aided manufacturing technology seems to be an interesting way to promote both business and safety, being more comfortable for patients and more accurate than traditional technology. A further advantage is easier infection prevention since, for the most part, mainly digital impression and casts are not a source of cross-infection and the transport of contaminated items is reduced and limited to try-in stages. Nevertheless, a peculiar feature is that a digital electronic file is of course unalterable, but may be ruined by a computer virus. Additionally, the reconditioning of scanner tips is determinant for the optical characteristics and long term use of the scanner, but information for its reconditioning from producers is often limited. This study focuses on some critical points including (a) insufficient guidelines, (b) choice of proper procedure for scanner reconditioning, and (c) data protection in relation to patient privacy.
Topics: Computer-Aided Design; Dental Implants; Dental Impression Materials; Dental Impression Technique; Dentistry; Humans; Infections
PubMed: 31467901
DOI: 10.1155/2019/6092018