Custom Impression Trays Research Articles

An Evaluation of Retention of Complete Denture Bases Made with a “Modified Single-stage Impression” Technique Using a Heat-moldable Tray

Abstract Aim: Although most dental schools teach complete denture definitive impression techniques consisting of secondary impressions in border-molded custom impression trays, it has been found that later, graduates in clinical practice abandon this step because of its complexity and attempts to seek easier alternatives. To simplify two-stage techniques, single-step border molding with elastomeric impression materials and light-cured resin materials has gathered acceptance among clinicians. The study aims to evaluate the retention of record bases made with a modified single-stage impression technique that uses elastomeric impression material in a heat moldable tray with modeling compound as material for border molding. Settings and Design: This was an in vivo preliminary cohort study. Materials and Methods: Thirteen completely edentulous patients requiring complete dentures were included in the study. A traditional two-stage impression was made using custom trays fabricated over diagnostic casts and further border molding done with a modeling compound, and the final impression was made to use zinc oxide–eugenol impression material. Additionally, a modified single-stage impression technique using heat moldable impression trays was made. Master casts from each technique were made, and further record bases were made on each master cast. Wire loops were adapted on the palatal aspect of record bases. The retention of each record base was evaluated using a force gauge. Statistical Analysis: The Kolmogorov–Smirnov test was used to analyze the normality of variables and later Wilcoxon signed-rank test was applied. Results: The double-stage technique exhibited retention values in the range of 0.6–66.7 units, whereas the single-stage technique showed a range of 0.15–78.55. The tests showed no significant difference between double-stage and single-stage techniques (P > 0.05). Conclusions: The single-stage technique using heat moldable trays with elastomeric impression material and modeling compound as a material for border molding can produce denture retention compared to the conventional technique that uses a two-step impression technique. The use of the modified single-stage technique can additionally save an extra appointment for patients, although it is better to use such a technique as an advanced impression technique and not as a training technique for beginners or students, as the material cost is substantially higher than the conventional two-stage technique.

Chairside 3-D printed impression trays: a new approach to increase the accuracy of conventional implant impression taking? An in vitro study

PurposeA high transfer accuracy of the intraoral implant position to a model is required, to manufacture implant-supported restorations. However, clinically relevant deviations persist between the intraoral implant position and the model obtained, even for the benchmark conventional custom implant impressions with polyether. Thus, new approaches using 3-D printed impression trays may increase the transfer accuracy of implant impressions. The ability to adjust parameters such as the thickness of the layers and the influence of the openings in the impression tray could potentially affect accuracy.MethodsFour different types of impression trays (n = 10 for each group) for the conventional impression technique were investigated: conventional custom impression tray, customized foil tray, chairside 3-D printed impression tray with the SHERA system, and the Primeprint system using an implant master model with four implants in the posterior region and a reference cube. After plaster model casting, all models were measured using a coordinate measuring machine, and the deviation from the reference dataset was determined. A statistical ANOVA analysis was performed (p < 0.05).ResultsChairside 3-D printed impression trays showed the best results, followed by conventional custom impression trays. Implant impressions obtained using a customized foil tray exhibited the lowest accuracy. Statistically significant differences were observed between 3-D printed impression trays and conventional custom impression and customized foil trays (p < 0.05). Whereas, the implant position did not have any significant influence on accuracy (p > 0.05).ConclusionsChairside 3-D printed impression trays significantly increase the transfer accuracy for implant impression taking.Graphical

Dimensional Stability and Retention Strength of Impressions to Custom Impression Trays Fabricated Using Conventional Method and Additive Technology - An In-vitro Study.

3D printing technology is replacing manual fabrication in all fields. 3D-printed impression trays should be assessed as they could replace conventional impression trays in the future. In-vitro comparison and evaluation of the dimensional stability and retention strength of impressions to custom impression trays fabricated using conventional method and additive technology. A maxillary edentulous auto-polymerizing acrylic resin model served as the master model. Two moulds were prepared from the master model in order to obtain 12 casts. One cast was scanned for 3D printing digital light processing (DLP) and fused deposition modelling (FDM) 24 impression trays using polylactic acid (PLA). Twelve casts were used to fabricate light cure impression trays. Polyvinyl-siloxane impressions were made on the master model using 36 impression trays and 18 trays each were used to assess dimensional stability and retention strength. In dimensional stability analysis, one sample t-test revealed a statistically significant difference between each group and the master model followed by a one-way ANOVA. There were significant differences, but the difference was less with FDM trays (P < 0.05). In retention strength analysis, one-way Analysis of variance (ANOVA) revealed statistically significant difference between each group and post-hoc test revealed specific difference, the highest with FDM trays (P < 0.05). Dimensional changes were observed at 30 minutes and 72 hours. Lesser dimensional changes were observed when impressions were made using FDM trays followed by DLP and light cure trays. The mean retention strength seen in descending order was FDM, followed by DLP and light cure trays. The best retention strength was noticed when impressions were made using FDM trays.

Customized Preliminary Impression: A Novel Impression Technique for Severely Resorbed Edentulous Ridges

Patients with long-term edentulism and/or ill-fitting (poorly fitted) dentures are more likely to experience severe mandibular alveolar ridge resorption. Some of these patients have genial tubercles that rise over the mandibular residual ridge in the anterior region and protrude into the floor of the mouth. Typically, the most prominent portions of the resorbed mandibular edentulous ridge are in contact with the lingual flanges of the mandibular stock impression trays (i.e., genial tubercles and internal oblique lines). In these situations, it is advised that a preliminary custom impression tray be created to pour an initial impression, allowing for the fabrication of individual custom trays. In general, dental practice for the fabrication of the complete denture, the stock trays are used for making the preliminary impression and the custom trays for the final impression. The present article portrays an innovative and efficient clinical technique involving the fabrication of a customized preliminary impression tray for preliminary impression making particularly in unconventional situations, that is, pronounced mandibular alveolar ridge resorption.

Defining challenging areas of the preparation finish line by using an open-source 3D modeling computer program: A tip to simplify margin identification by the dental laboratory technician

Intraoral data acquisition and computer-aided design and computer-aided manufacturing (CAD-CAM) systems have simplified and expedited the fabrication of dental prostheses. 1 Van Noort R. The future of dental devices is digital. Dent Mater. 2012; 28: 3-12 Crossref PubMed Scopus (801) Google Scholar ,2 Giuliodori G. Rappelli G. Aquilanti L. Intraoral scans of full dental arches: an in vitro measurement study of the accuracy of different intraoral scanners. Int J Environ Res Public Health. 2023; 20: 4776 Crossref Scopus (0) Google Scholar Contemporary dental CAD-CAM provides the freedom to design and fabricate diverse dental devices, including custom impression trays, surgical templates, and removable and fixed dental prostheses. 1 Van Noort R. The future of dental devices is digital. Dent Mater. 2012; 28: 3-12 Crossref PubMed Scopus (801) Google Scholar ,3 Revilla-León M. Özcan M. Additive manufacturing technologies used for processing polymers: current status and potential application in prosthetic dentistry. J Prosthodont. 2019; 28: 146-158 Crossref PubMed Scopus (217) Google Scholar ,4 Turkyilmaz I. Wilkins G.N. Varvara G. Tooth preparation, digital design and milling process considerations for CAD/CAM crowns: understanding the transition from analog to digital workflow. J Dent Sci. 2021; 16: 1312-1314 Crossref Scopus (8) Google Scholar These dental appliances are created from a digital file that recreates the surface geometry of the target object, typically a standard tessellation language (STL) file. 5 Grant G.T. Campbell S.D. Masri R.M. Andersen M.R. The American college of prosthodontist digital dentistry glossary development task force. Glossary of digital terms. J Prosthodont. 2016; 25: S2-S9 Crossref PubMed Scopus (27) Google Scholar A prerequisite for accurate manufacture is the exact capture and identification of the fine details in the target intraoral structures. An accurate capture can be challenging when the preparation finish line is subgingival, when abundant bleeding or salivation occurs, or when operator scanning skills and speed are still developing. 6 Mangano F. Gandolfi A. Luongo G. Logozzo S. Intraoral scanners in dentistry: a review of the current literature. BMC Oral Health. 2017; 17: 149 Crossref PubMed Scopus (308) Google Scholar Additionally, the location of fine details can be challenging for the dental laboratory technician to visualize when the CAD file is outsourced for the manufacture of the definitive restoration, since STL files lack attributes such as color and texture. 5 Grant G.T. Campbell S.D. Masri R.M. Andersen M.R. The American college of prosthodontist digital dentistry glossary development task force. Glossary of digital terms. J Prosthodont. 2016; 25: S2-S9 Crossref PubMed Scopus (27) Google Scholar These features help differentiate the tooth from its surrounding tissues when finish lines are subgingival or when displacement is limited. The present article presents a straightforward workflow that defines challenging areas of the preparation finish line by using an open-source 3D modeling computer program. This procedure can be used to communicate the finish line observed to the dental laboratory technician when STL files are used to design the definitive restoration and stops the technician guessing the finish line, since the hard-to-see areas are defined by the clinician. Additionally, this approach has advantages over the margin tracing and sculpting tools available in most 3-dimensional (3D) CAD computer programs since it allows selecting the critical areas around the finish line considering the mesh geometry of the 3D file. Visualizing the 3D mesh permits a more precise selection, which can minimize distortion as even the smallest changes in the mesh surface can be observed if transformation or sculpting procedures are used.

COMPARATIVE EVALUATION OF THE EFFECT ON THE RETENTION OF MAXILLARY DENTURE BASE BY USING TWO DIFFERENT BORDER MOLDING TECHNIQUES AND TWO DIFFERENT MATERIALS- AN IN VIVO STUDY

Purpose: This study was undertaken to compare the retention between sectional border molding using low fusing greenstick compound and single step border molding using condensation silicone (putty) impression material in two stages- A. After final impression and B. With the temporary denture base. Materials &amp; Methods: In this study evaluation of retentive values of sectional border molding (Group I) (custom impression trays border molded with green stick compound ) and single step border molding (Group II) ( border molding with condensation silicone (putty) impression material ). In both techniques definitive wash impression were made with light body condensation silicone and denture base with auto- polymerization resin. Results: Group 1B was significantly higher (mean- 2.176) than Group 1A (mean- 1.798) in test-1. The t-value (6.023) infers that there was significant difference between Group 1A and Group 1B (p =0.001). Group 2B was significantly higher (mean- 2.344) than Group 2A (mean-2.111) in test -2. The t-value (2.852) infers that there was significant difference between Group 2A and Group 2B (p=0.001). Conclusion: Within the limitations of this clinical study border molding using custom tray with low fusing green stick compound provided significant difference for retention as compared to condensation silicone at border moulding and denture base stage.

Effect of Plastic Impression-Transfer Copings on the Dimensional Accuracy of Implant Impressions

Purpose: The purpose of this in vitro study was to evaluate the effect of plastic impression transfer copings on the dimensional accuracy of close tray implant impressions. Methods: A master model was constructed using autopolymerizing acrylic resin. Five parallel holes were drilled for implant analogs. Custom impression trays were made with autopolymerizing polymethyl methacrylate resin. The study consisted of 2 groups (n=5): (group 1) Impression was obtained with using plastic impression transfer coping (group 2) Impression was obtained without using plastic impression transfer coping. Vinylpolysiloxane impression material was used for both groups. After the impression were obtained, casts were made by type IV dental stone. Casts were scanned with the lab-type scanner and transferred to the measurement program. Measurements were made from a specific reference corner for each analog to ensure standardization. Data were saved as millimeters and pairwise comparisons were made with Welch's t-test analysis. Results: The effect of plastic caps was evaluated by applying the t-test to each distance. For all distances, the distortion seen in the measurements taken without the cap is higher than the measurements taken with the cap, but no significant differences were found (p&amp;gt;0.05). Conclusions: In the anterior-posterior distances, the distortions were found compression type, in the right-left distances the distortions were found as expansion-type. There is a dimensional change in the measurements taken without a cap, but no clinically significant differences were found.

Determination of the lingual border of lower complete dentures: How to use a silicone impression material?

This study aimed to clarify the efficacy of a border-moulding procedure with low-flow silicone impression material compared with a conventional compound to complete denture fabrication. It also aimed to evaluate the influence of various functional tasks during the lingual-side moulding procedure regarding the depth and width of the border. Ten dentate subjects (three men, seven women; average age 30years) were enrolled in this study after giving informed consent. A specially designed custom impression tray for the mandibular lingual side was fabricated for each subject. With the tray and heavy-body-type silicone material, lingual border moulding was performed that included four functional tasks: tongue protrusion (TP), licking the upper lip with the tongue (UL), swallowing (SW), and placing the tongue tip to the palate (PP). Within the limitations of this study, the results suggested that heavy-body silicone impression material is satisfactory for use in the border-moulding procedure, giving reproducible results. There were no significant differences among the functional tasks regarding the depth and width of the lingual flange except for swallowing, which exhibited the largest values.

To evaluate the effect of storage temperature on the linear dimensional accuracy of delayed and repeat pours of two addition silicone impression materials

Background: Addition silicone elastomers are the most commonly used impression materials for making final impression for fixed partial dentures, implants, and removable partial dentures. The dimensional stability and accuracy of addition silicone impression material is influenced by the storage time, temperature, and repeat pour. Aim and Objectives: The aims and objectives of this study were to evaluate the accuracy of two different types of addition silicone elastomeric impression materials, stored at different temperatures; to evaluate the accuracy of two different types of addition silicone elastomeric impression materials after delayed and repeated pour; and to compare the linear dimensions of two different types of addition silicone elastomeric impression materials with a control die. Materials and Methods: A machined standard steel master die and a metal custom impression tray were made for making a final impression of machined standard steel master die. The final impression was made by using two different brands of addition silicone impression materials (Aquasil™ Ultra Impression material, Dentsply/Caulk, Milford, DE, USA, and 3M™ ESPE™). Double-step putty light-body impression technique was used for making the final impression. In this manner, a total of eighty impressions were made, and they were divided into two groups namely Group I and Group II. To study the effect of delayed pours and storage temperature, the two groups were further divided into four subgroups, with ten impressions each. All the ten impressions of each subgroup were stored in an acrylizer at 40°C, −10°C for 24 h, −2°C for 48 h, and 0°C for 1 week inside a refrigerator in sealed plastic bags before being poured with type IV dental stone. To study the effect of repeat pours on the accuracy of stone casts, all the ten impressions of each subgroup were immediately re-poured with type IV die stone after the removal of the first set of casts. Thus, again a fresh set of eighty casts were obtained having forty casts to each group. Results: When the impressions were stored in the acrylizer at 40°C, −10°C for 24 h, −2°C for 48 h, and 0°C for 1 week, the addition silicone impression materials did not show any significant change when compared to the control samples. Conclusion: Both the types of addition silicone elastomeric impression materials maintained their accuracy after delayed pours and repeat pours. Storing impressions under different conditions caused no adverse effect upon the accuracy of both types of addition silicone elastomeric impression materials. There was no significant change in the dimensions of stone casts obtained from both impression materials as compared to the dimensions of the master die. Even though if the addition silicone impression material is delayed, i.e. poured up to 1 week, repeat poured, and exposed from − 10°C to 40°C, the linear dimensional accuracy will not be adversely affected.

CAD/CAM produced complete dentures with the «Digital Denture Professional System».

The article describes the medical and dental procedures for four treatment sessions with the Digital Denture Professional (DDP) system. First, conventional preliminary dental impressions of the full arch are taken to achieve accurate jaw positioning records. The study models and patient data are digitalised using a laboratory scanner. The dental lab technician then constructs and mills custom impression trays and a mount as an intraoral instrument. A closed-mouth impression is then taken to record vertical dimensions and central relation position. After this is digitalised in the laboratory, DDP add-on software is used to virtually design the full dental implants and mill monolithic test implants. These can be tested for aesthetics, function and phonetics in the third session. The testing phase can also be skipped on request. In the last session, the final dental implants are fitted for the patient. The patient’s individual data are precisely recorded and digitally processed, which ensures the results are always as planned. The patient benefits from the spared time and costs. The range of care will be expanded in future to include reconstructions using implants. The digitalisation of the technique would be ideal for the planning and provision of digital implant prosthetics.

Technique for adapting a spacer for a custom impression tray

A method of adapting a spacer for the custom trays used to make a definite impression for complete dentures is presented. The technique can be used under a variety of conditions and offers several advantages.

A Clinical Review of Spacer Design for Conventional Complete Denture

One of the key factors affecting the outcome of the treatment is the impression procedure involved in the fabrication of complete denture prosthesis. Various impression philosophies have been proposed over years by various authors, out of which the selective-pressure impression technique is most accepted. In this technique, by using custom trays with spacers of different materials and designs, vulnerable tissues are relieved and stresses are distributed selectively to biomechanically sound tissues. But the dentist usually uses stock tray for making primary impression as well as final impression due to the lack of knowledge of the following: optimum material for making custom impression tray, adequate extension, required thickness and designs of spacer, tissue stops, escape holes, tray handles, and polymerization time regarding custom impression trays in prosthodontics. This article will give a clear view to the dentists to use accurate spacer design, material and thickness, tissue stops, and escape holes, based on various clinical situations in their practice.

Single Step Impression Technique - A Case Report

Recent advances in impression materials and impression trays have resulted in simplified approaches to impression making in removable prosthodontics. Once considered an absolute necessity, it is now possible to avoid the need for custom impression trays and achieve reliable master casts in a single appointment. New and innovative procedures are now available for giving the patient better results in case of complete denture1,2. The present case report highlights the modern technique using readily available impression materials, that gives us the primary and secondary impression in single appointment, and can be incorporated in the daily management to improve the stability and retention of denture and quality of life in edentulous patients.

A simple technique to control the heat generated during light polymerization of custom impression trays

Custom traysare commonly made with a light-poly-merizing acrylic resin material (TriadTruTray; Dentsply Intl) over a waxspacer. The material is polymerizedin a light unit (Triad 2000; DentsplyIntl). The manufacturer recommendsa polymerization time of 2 minutes,followed by removal of the softenedwax. This frequently results in thewax melting, which produces a residuefilm on the custom tray surface. Aprocedure for preventing the wax spacerfrom melting during the polymerizationof light-polymerized acrylic resin isdescribed.

The Influence of Tray Space and Repeat Pours on the Accuracy of Monophasic Polyvinylsiloxane Impression

While literature demonstrates that the optimum accuracy is obtained with the custom trays, the use of stock trays for elastomeric impressions appears to be popular in general practice. The aim of the study was to evaluate the effect of thickness of impression material on the dimensional accuracy of impressions made from monophasic polyvinylsiloxane impression material. This study also studies the dimensional stability of the impressions poured at different time intervals. A metal model simulating two abutment teeth was fabricated along with reference lines inscribed on them. Custom impression trays were fabricated with spacer thickness of 2, 4 and 6 mm. impressions were made using monophasic polyvinyl siloxane impression material. The impressions were poured and stone models were obtained. The dimensional accuracy of the impressions were determined indirectly by measuring the dimensional changes of the recovered stone models. The dimensional stability was also evaluated by pouring the impressions at time intervals of 1 hour, 24 hours and 7 days. The obtained data was statistically analyzed. The results of the study indicated that the impressions made from 2 and 4 mm tray space produced more accurate stone models when compared to 6 mm tray space. There was no significant deviation in the mesiodistal and buccolingual dimensions when impressions were made using impression trays with 2, 4 and 6 mm tray spacers. There was a significant decrease in interabutment distance (p = 0.001) and height of the abutment (p = 0.024) when impressions were made using impression trays with a tray space of 6 mm. There were no significant differences found among the stone models obtained from 1 hour, 24 hours and 1 week pour times. The mesiodistal and buccolingual dimensions of the abutments were not affected by the variations in thickness of impression material. There was a decrease in the height of the abutment which was clinically not significant. As the thickness of the impression material increased, the interabutment space decreased, which is a factor of concern when impressions are made for fixed partial dentures. When monophasic polyvinylsiloxane is used as the impression material, stock trays can be used for making impressions for individual castings.

The Removal Force of Some Custom Impression Tray Materials

The Removal Force of Some Custom Impression Tray Materials

Sectional Impression Tray and Sectional Denture for a Microstomia Patient

Microstomia presents a unique challenge to the patient. Patients with microstomia who must wear removable dental prostheses often face the difficulty of being unable to insert or remove the prosthesis because of the constricted opening of the oral cavity. A completely edentulous patient, who developed microstomia along with Raynaud's phenomenon induced by scleroderma, is presented. This clinical report describes a quick and easy method for fabrication of a sectional custom impression tray connected by press button and a sectional complete denture retained by magnets. A sectional denture that provides ease in placement and removal can be successfully used in clinical practice for treatment of microstomia patients.

Simple technique to transfer occlusal vertical dimension and articulate a definitive implant cast for a full arch implant prosthesis

Papaspyridakos and Lal Papaspyridakos and Lal The dental literature is replete with techniques for registering maxillomandibular relationships and transferring them accurately to the articulator. For edentulous patients receiving implants, several methods have been described for articulating the definitive implant cast at the appropriate occlusal vertical dimension (OVD) in the centric relation (CR) position.1-6 Techniques available for mounting the definitive implant cast on the articulator include record bases with occlusion rims supported by the healing abutments, or screwretained record bases.1,2 Other options involve the use of a duplicated denture with acrylic resin as a custom impression tray, or even a duplicated denture with vinyl polysiloxane (VPS). 3-6 A time-saving chairside technique is presented for the articulation of the implant definitive cast, maintaining the established OVD, and subsequent fabrication of a silicone index to assist in prosthesis design, both performed in a single visit. The existing denture can then be easily converted into an interim fixed prosthesis on the articulator, thus minimizing chair time and increasing patient comfort and satisfaction.

Alternate technique for fabrication of a custom impression tray for definitive obturator construction

Prosthodontic rehabilitation for an acquired maxillary defect begins immediately at the time of surgical resection. 1 Curtis T.A. Marunick M.T. Beumer III, J. Maxillofacial rehabilitation: prosthodontic and surgical considerations. Ishiyaku Euroamerica, St. Louis1996: 225-247 Google Scholar , 2 Keyf F. Obturator prostheses for hemimaxillectomy patients. J Oral Rehabil. 2001; 28: 821-829 Crossref PubMed Google Scholar Abrupt alteration of physiologic functions such as speech, mastication, deglutition, and salivary control associated with ablative surgery requires timely prosthetic intervention. 3 Umino S. Masuda G. Ono S. Fujita K. Speech intelligibility following maxillectomy with and without a prosthesis: an analysis of 54 cases. J Oral Rehabil. 1998; 25: 153-158 Crossref PubMed Scopus (49) Google Scholar

Fabrication of a custom impression tray using a thermoplastic material as the tray spacer

Custom impression trays are recommended for fixed partial denture impressions because of dimensional accuracy, comfort, and cost-effectiveness. A review of the literature indicates a lack of agreement on the best technique or method to be used for custom tray fabrication. The use of custom impression trays for definitive impressions has several advantages; however, making a traditional wax spacer for the tray may be a time-consuming step. This article describes a technique that saves time by using a thermoplastic material to form the spacer. The result is an impression tray that is comfortable to the patient and assures even and sufficient thickness of impression material. This technique allows the fabrication of a custom impression tray with a spacer that has several positive features. First, the original use of the spacer material is for fabrication of bleaching trays, so the material is readily available. Although spacer material is somewhatmore expensive than wax, the decreased time required to adapt the wax to the cast may offset the additional cost of the material. Secondly, consistent 2.0to 3.0-mm spacing within the custom impression tray is provided. Care must be taken when heating the spacer material, since excessive heating can distort the spacer during the vacuum-forming process, resulting in unacceptably thin areas of spacer. This may result in the impression or poured cast being difficult to remove. A second layer of bleaching tray material may be used to increase space if necessary. Third, the spacer may be reused to make another tray, if necessary. This article describes a technique that replaces the wax spacer with a flexible thermoplastic material, resulting is a less time-consuming procedure.