A technique for assessing the fit of a removable partial denture framework on the patient and on the definitive cast

Hsu, Yung-tsung

doi:10.1016/j.prosdent.2016.02.008

Cited by 5 publications

(4 citation statements)

References 7 publications

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“…Silicone film method is commonly performed by inserting silicone impression material between the RPD and intraoral dentition or master model under a retentive force that is maintained through the setting time. The the silicone replica of the gap may be sectioned afterwards and its thickness directly revealing the gap was measured with stereomicroscope, digital microscope, electronic calipers or profile projector [ 18 , 35 , 45 , 46 ]. However, Yoon et al reported that the number of measuring points have effect on the average thickness of the silicon replicas, and that the accuracy of silicone film method was not sufficiently reliable [ 47 ].…”

Section: Discussionmentioning

confidence: 99%

“…However, the low overall internal discrepancy value is not equivalent to better fit, as it is the compounded result of individual components. The RPD rests could be the ideal reference for the fit evaluation, which is easy for measurement and important for functional loading of the overall framework [ 45 ]. The fit accuracy of other RPD components, namely the connectors, the clasp arms as well as denture base should be further investigated for both digital and conventional fabrication technologies.…”

Section: Discussionmentioning

confidence: 99%

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Fit accuracy in the rest region of RPDs fabricated by digital technologies and conventional lost-wax casting: a systematic review and meta-analysis

Qiu,

Liu,

et al. 2023

BMC Oral Health

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Background Digital technologies have recently been introduced into the fabrication of removable partial dentures (RPDs). However, it is still unclear whether the digitally fabricated RPDs fit better than conventionally cast ones in the rest region. The aim of this study was to evaluate the fit accuracy in the rest region of RPDs fabricated by digital technologies and compare it to those made by conventional lost-wax (CLW) technique. Methods A comprehensive search was conducted in Cochrane Library, PubMed, EMbase, Web of Science and SpringerLink. Studies published up to August 2022 were collected. Two authors analyzed the studies independently and assessed the risk of bias on the modified methodological index for non-randomized studies (MINORS) scale. The mean values of gap distance between rests and corresponding rest seats of each study were extracted as outcome. A random-effects model at a significance level of P < 0.05 was used in the global comparison and subgroup analysis was carried out. Results Overall, 11 articles out of 1214 complied with the inclusion criteria and were selected, including 2 randomized controlled trials (RCTs), 1 non-randomized clinical trial and 8 in vitro studies. Quantitative data from Meta-analysis revealed that fit accuracy in the rest region of RPDs fabricated with CLW showed no statistically significant difference with digital techniques (SMD = 0.33, 95%CI (-0.18, 0.83), P = 0.21). Subgroup analysis revealed a significantly better fit accuracy of CLW-fabricated RPDs in the rest region than either additive manufacturing (AM) groups or indirect groups (P = 0.03, P = 0.00), in which wax or resin patterns are milled or printed before conventional casting. While milled RPDs fit significantly better than cast ones in the rest region (P = 0.00). With digital relief and heat treatment, hybrid manufactured (HM) clasps obtained better fit accuracy in the rest region (P < 0.05). In addition, finishing and polishing procedure had no significant influence in the fit accuracy in all groups (P = 0.83). Conclusions RPDs fabricated by digital technologies exhibit comparable fit accuracy in rest region with those made by CLW. Digital technologies may be a promising alternative to CLW for the fabrication of RPDs and additional studies are recommended to provide stronger evidence. Trial registration CRD42020201313.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Fit accuracy in the rest region of RPDs fabricated by digital technologies and conventional lost-wax casting: a systematic review and meta-analysis

Qiu,

Liu,

et al. 2023

BMC Oral Health

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“…After setting of the PVS, the frameworks with the registration material were removed and excess materials were trimmed and a light body rubber base impression material was injected on the fitting surface of the PVS material and immediately placed in the patient mouth ensuring that all the components were in their position intraorally. After setting of the impression material, the frameworks were removed from the mouth and careful measurements of the thickness of the impression materials at different locations were performed by a single examiner [16]. The resulted measurements were statistically analyzed using the two-tailed t-tests.…”

Section: Clinical Evaluationmentioning

confidence: 99%

Clinical and Laboratory Evaluation of the Fit Accuracy of Metal Frameworks of Removable Partial Denture Fabricated from Two Different Pattern Materials

Abdel-Fattah¹

2019

ohdm

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Objective: The purpose behind this conducted study was clinical and laboratory assessments of the fit accuracies of cobaltchromium frameworks for removable partial dentures fabricated by traditional lost wax technique (TT), and the Light Cure Modeling Material Technique (LCMT). Materials and Methods: Sixteen healthy male Kennedy class I patients were selected from the specialty clinics in the Faculty of Dentistry, Taif University. The patients were divided into two Groups eight patients each; Group I: their metallic framework was constructed from the traditional lost wax patterns technique (TT), Group II: their metallic framework was fabricated by Light Cure Modeling Material Technique (LCMT). Conventional clinical and laboratory steps for construction of metallic partial denture were followed. The frameworks resulted from the two pattern materials were tested clinically and laboratory for fit accuracies and the results were statistically analyzed using the two-tailed t-tests. Results: Clinical results show an appropriate thickness of the impression materials and improved fit accuracy of the Light cure group in comparison to the traditional wax pattern group. Laboratory findings also showed that the Light cure group has significantly smaller mean gap values than the traditional wax pattern group. Conclusions: The fit accuracies of cobalt-chromium frameworks of removable partial denture fabricated from LCMT are better than that fabricated from TT.

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“…Accurate master casts are fundamental to the successful rehabilitation of partially edentulous patients with removable partial denture (RPD) prostheses. One of the greatest challenges in the treatment of partially dentate patients is lack of fit of the RPDs [1]. Such RPD's will usually fit the master cast but not intraorally; this is an indication that the master cast may have been poured from an inaccurate impression.…”

Section: Introductionmentioning

confidence: 99%

The influence of undercut depths on the accuracy of casts poured from irreversible hydrocolloid impression materials

Mudliar

Vuuren

et al. 2020

Heliyon

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Objectives: To evaluate the elastic recovery of a typical irreversible hydrocolloid impression material in terms of the amount of undercut identified and additional thickness of spacer provided before custom tray fabrication. Methods: This study surveyed the undercut depths of the teeth surfaces and lingual sulci of one hundred partially dentate mandibular dental casts which were subsequently scanned and the data exported as STL files. A typical cast from each undercut category (0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm, 5mm) was 3D printed. Three custom trays were constructed with spacer thicknesses representing 20%, 30% and 50% compression against the wall of the custom trays on removal, impressions recorded, and casts fabricated in dental stone. Measurements for elastic recovery of irreversible hydrocolloid were done using an internal caliper and a digital caliper. All measurements were done by the principal investigator. Non-parametric analyses were used for comparisons of the undercut values between the 3D printed and poured casts to determine the amount of elastic recovery of the irreversible hydrocolloid impression material. Results: There was no statistically significant difference in measurements between the original 3D printed casts and the poured casts, irrespective of percentage compression (p > 0.05). Conclusions: In removable partial denture construction, casts should be blocked out parallel to the path of insertion and then an additional 3mm of spacer applied as a standard technique before custom tray fabrication to ensure elastic recovery of the irreversible hydrocolloid impression. Clinical implications: In severe undercut situations, accurate impressions can be taken using irreversible hydrocolloid by blocking out all undercut surfaces on the teeth and lingual sulci before adapting additional threemillimetre wax spacer on casts when constructing custom trays thereby ensuring accurate and reliable impressions for removable prosthesis construction.

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A technique for assessing the fit of a removable partial denture framework on the patient and on the definitive cast

Abstract: Figure 2. A, Inject low viscosity polyvinyl siloxane material on tissue surface and place intraorally. B, Evaluate thickness of impression material.

Cited by 5 publications

References 7 publications

Fit accuracy in the rest region of RPDs fabricated by digital technologies and conventional lost-wax casting: a systematic review and meta-analysis

Fit accuracy in the rest region of RPDs fabricated by digital technologies and conventional lost-wax casting: a systematic review and meta-analysis

Clinical and Laboratory Evaluation of the Fit Accuracy of Metal Frameworks of Removable Partial Denture Fabricated from Two Different Pattern Materials

The influence of undercut depths on the accuracy of casts poured from irreversible hydrocolloid impression materials

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