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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 -
Indian Journal of Dental Research :... 2023Impression making is one such important clinical step, which is critical in the accurate fitting of resulting prostheses. Impression making itself depends on the type of...
INTRODUCTION
Impression making is one such important clinical step, which is critical in the accurate fitting of resulting prostheses. Impression making itself depends on the type of material and the impression technique used to record the details. Various combinations of material and the technique have been described in the literature.
AIM
To evaluate the effect of three different impression techniques on the marginal fit of computer-aided designed/computer-aided manufactured (CAD/CAM) single unit composite fixed dental prostheses (FDP), different consistencies of addition silicone impression material and different tray design were utilized.
METHOD
Impression of prepared tooth on typodont was made using Matrix impression system, two-step putty wash technique, and individual tooth tray technique. Prosthesis was fabricated using CAD/CAM technology and marginal accuracy was evaluated using scanning electron microscopy (SEM).
RESULT
In the present study, the matrix impression system resulted in less microgap in both mid-buccal and mid-mesial region, whereas putty wash technique showed very high standard deviation in the interproximal region.
CONCLUSION
Matrix impression system had the best results at both mid-buccal and mid-mesial position with least marginal discrepancy.
CLINICAL IMPLICATION
The findings of this study could be used by clinicians to help them choose the viscosity of polyvinylsiloxane material and impression techniques for FDP that will result in high-accuracy impressions and well-fitting prostheses.
Topics: Computer-Aided Design; Dental Impression Materials; Microscopy, Electron, Scanning; Silicones
PubMed: 38197350
DOI: 10.4103/ijdr.ijdr_991_22 -
Journal of Dentistry Dec 2022To assess time efficiency and the efficacy of the prosthetic manufacturing for implant crown fabrication in a centralized workflow applying computer aided design and... (Randomized Controlled Trial)
Randomized Controlled Trial
Time efficiency and efficacy of a centralized computer-aided-design/computer-aided-manufacturing workflow for implant crown fabrication: A prospective controlled clinical study.
OBJECTIVE
To assess time efficiency and the efficacy of the prosthetic manufacturing for implant crown fabrication in a centralized workflow applying computer aided design and computer aided manufacturing (CAD-CAM).
MATERIAL AND METHODS
Fifty-nine patients with one posterior implant each, were randomly allocated to either a centralized digital workflow (c-DW, test) or a laboratory digital workflow (l-DW, control). Patients were excluded from efficiency and efficacy analyses, if any additional restoration than this single implant crown had to be fabricated. A customized titanium abutment and a monolithic zirconia crown were fabricated in the c-DW. In the l-DW, models were digitalized for CAD-CAM fabrication of a monolithic zirconia crown using a standardized titanium base abutment. Time for impression, laboratory operating and delivery time were recorded. The efficacy of the prosthetic manufacturing was evaluated at try-in and at delivery. Data was analyzed descriptively. Statistical analyses using student's unpaired t- and paired Wilcoxon were performed (p < 0.05).
RESULTS
At impression taking, 12 patients (c-DW) and 19 patients (l-DW) were included. The impression time was 9.4±3.5 min (c-DW) and 15.1 ± 4.6 min (l-DW) (p < 0.05). The laboratory operating time was 130 ± 31 min (c-DW) and 218.0±8 min (l-DW) (p < 0.05). The delivery time was significantly longer in the c-DW (5.9 ± 3.5 1 days) as compared to the l-DW (0.5±0.05 days). At try-in and at delivery, efficacy of prosthetic manufacturing was similar high in both workflows.
CLINICAL RELEVANCE
The c-DW was more time efficient compared to the lab-DW and rendered a similar efficacy of prosthetic manufacturing.
Topics: Humans; Workflow; Prospective Studies; Titanium; Crowns; Zirconium; Computer-Aided Design; Computers; Dental Prosthesis Design
PubMed: 36252858
DOI: 10.1016/j.jdent.2022.104332 -
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 -
Prague Medical Report 2023During the fabrication of a complete denture, functional impression is taken. Literature studies show that polydimethylsiloxane (condensation silicone) has not been... (Review)
Review
During the fabrication of a complete denture, functional impression is taken. Literature studies show that polydimethylsiloxane (condensation silicone) has not been reported by United States dental schools to perform border molding. Thus, the purpose of this article is to review the functional impression technique when border molding is performed with a laboratory condensation silicone putty.
Topics: Humans; Silicones; Denture, Complete
PubMed: 38069643
DOI: 10.14712/23362936.2023.28 -
The Journal of Prosthetic Dentistry May 2023The treatment of infants with trisomy 21 (TS21) with a myostimulation plate can improve their development and quality of life. The manufacture of these plates requires...
The treatment of infants with trisomy 21 (TS21) with a myostimulation plate can improve their development and quality of life. The manufacture of these plates requires an accurate cast of the maxilla, and their efficacy relies on their stability and retention. As such, the quality of the impression is a determining factor. The lack of commercially available stock trays for infants with TS21 creates difficulties, including inadequate impression quality and the risk of inhaling impression material. The present technique simplifies impression making for infants with TS21 from 3 months of age to when their maxillary deciduous teeth erupt by using computer-aided design and computer-aided manufacturing (CAD-CAM) impression trays. Sixty-five stored gypsum maxillary casts from infants with TS21 that had been used to manufacture myostimulation plates were analyzed to select four differently sized representative casts for designing the impression trays. A CAD software program was used to digitally shape four sizes of the impression tray from the selected gypsum casts. Practitioners interested in this approach can download and export the standard tessellation language (STL) files using a quick response (QR) code. The impression trays should be manufactured with the stereolithography additive technique using biocompatible resin. This technique allows practitioners to make accurate maxilla impressions for infants with TS21 by manufacturing their own impression trays using the free-access STL files rather than the cumbersome conventional method.
PubMed: 37246097
DOI: 10.1016/j.prosdent.2023.04.015 -
International Journal of Implant... Nov 2019An accurate impression is crucial to the long-term success of dental implants. This investigation evaluated the accuracy of the open and closed implant impression...
BACKGROUND
An accurate impression is crucial to the long-term success of dental implants. This investigation evaluated the accuracy of the open and closed implant impression techniques in partially edentulous patients who received two adjacent implants.
MATERIAL AND METHODS
Forty patients received Osstem Implants (Osstem Implant System, Seoul, Korea). Two impressions were made for each patient, one using an open tray and a second with a closed tray technique. The horizontal distances between two impression copings were measured and compared to similar measurements on the master casts. Also, under a stereomicroscope (AmScop14370, Myford Road, #150, Irvine, CA 92606 USA) at a 50-fold magnification, the presence or absence of the marginal discrepancies was evaluated.
RESULTS
There were no statistically significant differences regarding horizontal measurements and in the marginal relationship for the two impression techniques, except between the anterior and posterior regions, for the closed tray technique. There were also no statistically significant differences in the impression accuracy between maxillary and the mandibular arches. In addition, there were no statistically significant differences for the intraoral horizontal distances, compared to similar horizontal measurements on master casts, between the open and closed tray techniques.
CONCLUSIONS
Within the limitations of the present study, there were generally no differences in the impression accuracy between the open and closed tray techniques in partially edentulous patients with two adjacent implants.
PubMed: 31741100
DOI: 10.1186/s40729-019-0190-6 -
Cureus Feb 2024Background The disinfection of dental impression materials is a cornerstone of infection control in dental practice. This study aimed to evaluate the effectiveness of...
Background The disinfection of dental impression materials is a cornerstone of infection control in dental practice. This study aimed to evaluate the effectiveness of two disinfectants, sodium hypochlorite and iodophor, on alginate and silicone impression materials, which are prone to microbial contamination. Methods The study was structured into two main groups based on the impression material: Group I (alginate) and Group II (addition silicone), each further subdivided into two subgroups for disinfection with sodium hypochlorite and iodophor. For each subgroup, initial microbial swabs were taken before any treatment, followed by a second swab after rinsing and a final swab after disinfection. The mean colony-forming unit (CFU) counts, standard deviations, and standard errors of the mean were calculated for each stage of treatment. Results Prior to disinfection, Group I had a mean CFU count of 2,529.40, while Group II had a lower mean CFU of 1,417.40. After rinsing, there was a significant decrease in CFUs in both groups, with Group I at 1,337.10 and Group II at 415.10. Post-disinfection, Group I showed a mean CFU count of 73.00 for sodium hypochlorite and 0.00 for iodophor. Similarly, Group II achieved a CFU reduction of 99.00 with sodium hypochlorite and 0.00 with iodophor, demonstrating a marked reduction in microbial presence. Conclusion Iodophor was exceptionally effective in disinfecting both alginate and silicone impression materials, eliminating all detectable CFUs. Sodium hypochlorite also significantly reduced microbial counts but was not as effective as iodophor. Rinsing prior to disinfection was instrumental in reducing the microbial load, underscoring its importance in the disinfection protocol.
PubMed: 38533142
DOI: 10.7759/cureus.54846 -
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 -
Clinical Oral Investigations Jul 2023Despite the clear drive from both research and clinical dentistry toward digital transformation, there are limitations to implementing intra-oral scanning (IOS) into...
OBJECTIVE
Despite the clear drive from both research and clinical dentistry toward digital transformation, there are limitations to implementing intra-oral scanning (IOS) into daily dental practice. This study aimed to compare the precision of digital models obtained from two alternative indirect workflows to direct IOS.
MATERIAL AND METHODS
Two indirect digital workflows were evaluated in this study. In the IOS group (direct), IOS directly obtained digital impressions of participants' upper and lower dental arches, while in the Scan Impression (Scan Imp) group (indirect), a desktop scanner scanned silicone-based impressions of upper and lower whole arches that were taken with plastic trays. In the cone-beam computed tomography impression (CBCT Imp) group (indirect), a CBCT machine scanned the silicone-based impressions. Then, the precision of the entire arch and individual teeth for all digital impressions was virtually quantified. Following superimposition, differences between standard tessellation language (STL) files obtained from both-direct and indirect-methods were evaluated by color-mapping and measuring the surface distance between superimposed STL files. Furthermore, 18 linear measurements were taken from each digital model. ANOVA with repeated measures, Pearson coefficient, and intraclass correlation coefficient were used for intergroup comparisons.
RESULTS
The digital models obtained from the two indirect workflows differed from the IOS in some dental and intra-arch measurements but were considered clinically acceptable. Ranked against IOS, CBCT Imp models had greater precision, followed by Scan Imp.
CONCLUSION
Digital models obtained from two indirect, alternative workflows, desktop, and CBCT scanning of impression, have clinically acceptable accuracy and reliability of tooth size and intra-arch measurements, providing the use of proper methodologies.
CLINICAL RELEVANCE
There are some limitations to implementing IOS in daily clinical practice. However, several alternative digital model production techniques might provide an affordable solution. Although they may insignificantly differ in accuracy, all can be applied clinically.
Topics: Humans; Computer-Aided Design; Models, Dental; Illusions; Reproducibility of Results; Workflow; Dental Impression Technique; Imaging, Three-Dimensional; Silicones
PubMed: 37046002
DOI: 10.1007/s00784-023-04996-2