Custom Tray Research Articles

Comparison of Accuracy of Direct Implant Impression Technique using Different Splinting Materials

ABSTRACT Introduction The accuracy of an impression remains critical factor in achieving passive fit of an implant framework. The accuracy of the master cast would depend on the type of impression material, the implant impression technique and accuracy of die material. The different impression techniques advocated in the literature for implant impressions include direct (open tray) and indirect (closed tray) techniques. Direct technique use square impression copings that are picked up in the impressions which were used in this study. Objective To evaluate the accuracy of direct impression made with resin splinted and bis-GMA splinted open-tray impression coping. Thus to compare the accuracy of impressions obtained using different splinting materials. Materials and Methods A wax mandibular reference model was fabricated and four implants were placed in the mandibular anterior region using surveyor and acrylized with clear heat cure acrylic resin using injection molding technique. Spaced primary cast was fabricated with a uniform thickness of space about 2 mm. Ten custom trays were fabricated using the light curable resin sheets. Medium body polyether impression material was used. Pentamix was used to get a uniform mix. These trays were randomly divided among the two groups, with five trays in each group. Impression techniques were divided into two groups namely: Group A - direct impression technique with open tray impression copings splinted with autopolymerizing acrylic resin (GC pattern resin), group B - direct impression technique with open tray impression copings splinted with Protemp TM4 (bis- GMA) syringable temporisation material. Thus, final impressions were made. Total of 10 master casts were fabricated. Evaluation of casts using Dynascope-Vision engineering, Tesa Microhite 2D and coordinate measuring machine were used. Results Statistical comparisons were made using ANOVA test and post-hoc test. Same amount of deviation values obtained with resin splinted and bis-GMA splinted impression copings. The difference in the values might be because of the variation in the rigidity of the materials used. Conclusion Both the splinting material exhibit similar accuracy in impression, so bis-GMA can be used, which is easy to handle, less time consuming, less technique sensitive, rigid and readily available material in clinics, instead of resin splinted material which is technique sensitive, more time consuming and cumbersome. How to cite this article Selvaraj S, Mohan J, Simon P, Dorairaj J. Comparison of Accuracy of Direct Implant Impression Technique using Different Splinting Materials. Int J Prosthodont Restor Dent 2014;4(3):82-89.

A screw-connected sectional impression tray for patient with limited opening

A procedure for fabricating a 2-piece custom tray is described. Implant analogs and gold cylinders are used to maximize the precision of the fit and the stability of the tray.

An alternative impression technique for complete dentures

This article describes a technique for creating adequate space for an even thickness of polyvinyl siloxane (PVS) impression material at the periphery during complete denture impression making. A PVS border molding material is injected around the borders of a custom tray, a 17-μm-thick stretch wrap film is folded into 4 layers, and a tray-shaped piece slightly larger than the size of the custom tray is placed on the tray covering the borders. After the border molding procedure is completed, the film is removed and the definitive impression completed with a medium-viscosity PVS impression material.

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.

A Complete Denture Impression Technique Survey of Postdoctoral Prosthodontic Programs in the United States

The purpose of the study was to survey program directors of postdoctoral prosthodontic programs in the United States regarding their programs' complete denture impression techniques. The key objectives of the survey were to identify the current trends in complete denture impression making and to determine which techniques and materials are taught in US postdoctoral prosthodontic programs. An online survey was sent to all program directors of US postdoctoral prosthodontic programs. The survey comprised two sections: preliminary impressions and final impressions. The survey contained 22 questions that would take approximately 5 minutes to complete. All responses remained anonymous throughout the survey. The response rate for the survey was 87%. A majority of the programs did not separately border mold the tray prior to making the preliminary impressions (82%). The impression material of choice for the preliminary impression was irreversible hydrocolloid (88%). Selective pressure was the predominantly used impression philosophy (80%). All programs border molded the custom tray, and 95% recorded the borders in sections. The material of choice for border molding the custom tray was modeling plastic impression compound (71%). The most commonly used impression material for the final impressions was polyvinylsiloxane (PVS) (42%), and the second most commonly used impression material was polysulphide (32%). The most common technique for locating the posterior palatal seal was marking intraorally and transferring onto the final impression (65%). Most programs routinely advised their patients not to wear their existing dentures for at least 24 hours before the final impressions were made (83%). Based on the results of this study, the following conclusions can be drawn: (1) The most commonly used material for the preliminary impression was irreversible hydrocolloid and for the final impression was PVS. (2) Modeling plastic impression compound was used by most programs to border mold the custom trays. (3) Selective pressure was the predominantly used impression philosophy. (4) A majority of the programs made a special consideration for excessive movable (flabby) tissue. (5) Most programs routinely advised their patients to not wear their existing dentures for at least 24 hours before the final impressions were made.

Quick and effective custom tray for a feeding obturator

Clefts of the lip and palate are the most common congenital craniofacial malformations in children. 1 Osuji OO Preparation of feeding obturators for infants with cleft lip and palate. J Clin Pediatr Dent. 1995; 19: 211-214 PubMed Google Scholar Sucking is impaired in infants born with clefts due to lack of negative pressure. 2 Jones JE Henderson L Avery DR Use of a feeding obturator for infants with severe cleft lip and palate. Spec Care Dentist. 1982; 2: 116-120 Crossref PubMed Scopus (24) Google Scholar Excess air intake during feeding, requiring additional burping, chocking, and nasal regurgitation of food are other complications associated with clefts. 3 Savion I Huband ML A feeding obturator for a preterm baby with Pierre Robin sequence. J Prosthet Dent. 2005; 93: 197-200 Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar A feeding obturator improves feeding and thereby contributing to weight gain and a thriving state of health, a prerequisite for surgical repair of the defects. 1 Osuji OO Preparation of feeding obturators for infants with cleft lip and palate. J Clin Pediatr Dent. 1995; 19: 211-214 PubMed Google Scholar The severity of the clefts varies so much that stock trays are not always adequate for making the impression, and a custom tray is required. This article describes a simple and effective technique for fabricating a custom tray for the infant patient.

Accuracy of face castings employing thermoplastic custom trays for facial molding

AIM: To evaluate the dimensional stability of a new facial molding technique using thermoplastic custom molding tray. METHODS: The designs established demarcation of facial anthropometrics landmarks, making linear measurements with a digital caliper. Facial molding was carried out using thermoplastic custom trays, constructing a facial plaster cast with the anthropometric landmarks already transferred by measuring the linear dimensions on the plaster cast and statistical analysis. RESULTS: All linear measurements in the palpebral and labial regions presented statistically significant distortions. Only one of the linear measurements from the orbital region did not demonstrate any significant distortion. The nasal region presented the least amount of distortion. CONCLUSIONS: Although statistically significant, distortions were due to the method of breathing and were considered to be clinically irrelevant. The reduction in the working time, the comfort provided to the patient and the dimensional accuracy of the plaster cast obtained by the facial molding technique using custom perforated molding tray suggest that this technique should be employed for making facial prostheses.

Dimensional accuracy of two rubber base impression materials as a function of spacer design and techniques in custom trays for fixed partial dentures

BackgroundA prostheses can't be better than the cast over which it has been fabricated. To make accurate casts, accurate impressions are mandatory. To get an accurate and dimensionally stable impression, various techniques and materials have been advocated. This study compares the most commonly used techniques and materials for dimensional accuracy. Two types of spacers were designed to compare the addition silicon and polyether and their techniques. MethodsA metal die was used to make the impressions. A total of 60 impressions were made using multiple mix and monophasic techniques for addition silicon and polyether in custom trays. A travelling microscope was used to measure the dimensional accuracy of die stone casts retrieved from impressions. ResultsThe results were compared using paired t test and SPSS software. The study was highly significant (p < 0.001). The polyether was more accurate than the addition silicon and spacer design I (adapted to the edentulous area) was more accurate than the design II (spacer over the abutments, not adapted to edentulous area). The multiple mix technique was more accurate than the monophasic for addition silicon. ConclusionThe combination of multiple mix technique with spacer design I for addition silicon gave the best accurate results.

Influence of procedural variations during the laboratory phase of complete denture fabrication on patient satisfaction and denture quality

ObjectivesTo compare subjective and objective outcomes of complete dentures fabricated with standard clinical protocols, but omitted selected steps during the laboratory phase. Materials and methodsForty-three edentulous patients (mean age 58.1 years, SD 9.9, range 35–78), were consecutively recruited and randomly assigned to one of four groups according to selected variations of laboratory steps: Group 1 (n=10), omission of secondary casts obtained from impressions in border moulded custom trays; Group 2 (n=10), omission of secondary casts and face-bow articulator mounting; Group 3 (n=10), omission of face-bow mounting; Group 4 (n=13), no steps omitted (control). Clinical procedures for all groups were identical, and performed by senior dental students under supervision of prosthodontists, all of whom were blinded to the Group. At 1-, 4- and 12-weeks after delivery, patients rated their overall satisfaction, as well as a range of functional factors using visual analogue scales. An independent blinded prosthodontist similarly rated four domains of denture quality at the 1-week follow-up. ResultsNo significant differences were noted among the groups in all aspects of patients’ assessments at all the time points (P>0.1). There were no significant differences in prosthodontists’ ratings of denture quality in any of the domains examined (P>0.1). ConclusionSelected omissions of steps (face-bow mounting and/or secondary casts) during the laboratory phase of complete denture fabrication has only a minor role, if any, in subjective and objective outcomes, contrasting with the common belief that such omissions will adversely affect outcomes. Clinical significanceGeneral practitioners provide most complete dentures. Many do not follow all the procedures they were taught at dental school. Our finding that omitting frequently advocated steps made no difference to patient satisfaction or to denture quality suggests that cost-effectiveness through simplifications be considered in practice and in education.

The Effect of One‐Step vs. Two‐Step Impression Techniques on Long‐Term Accuracy and Dimensional Stability when the Finish Line is within the Gingival Sulcular Area

To evaluate the effect of two putty-wash impression techniques on the long-term accuracy and dimensional stability of poly(vinyl siloxane) (PVS) in the gingival sulcus area. Impressions were taken from a master cast to simulate molar crown preparation. A space around the abutment served as the gingival sulcus. Fifteen impressions using the one- and two-step impression techniques were taken using Express Regular, Express Fast, and President impression materials with custom trays. Using a Toolmaker's microscope, the long (LD) and short distances (SD) of the abutment and the planar distance between two parallel lines (PL) at the circumference of the cast were taken at 0.5, 2, 24, 48, 72, 96, 120, and 144 hours after mixing. ANOVA was performed, with the discrepancy between the distances of the impressions and the master cast as the dependent variable. The differences when different materials and impression techniques were used were significant (p < 0.001) for LD, SD, and PL, as was the interaction between the material, time, and technique (p < 0.001). SD discrepancies were higher than those of LD for all materials and times. The two-step impression technique was more accurate, with smaller discrepancies than the one-step impression technique. For all materials, the PL discrepancy was deemed acceptable (less than 0.5%) for all tested times. President had higher discrepancies than the other materials. When using the two-step putty-wash impression technique, pouring of the impressions may be postponed up to 30 hours; however, when using the one-step impression technique, pouring should be performed within 2 hours.

The Effect of Full Crown Preparation on Normal and Inflamed Pulp Tissue: An Animal Study

Introduction: Full crown preparation may have adverse effects on pulp tissue. In this study, the effect of full-crown preparation on intact versus inflamed pulp tissue was studied. Methods: Fifteen healthy mature cats were randomly selected for this study. The study was performed on four canine teeth of each cat. Cats were anesthetized and then radiographs were taken from the canine teeth. Class V cavities were prepared in cat canine teeth. Soft decayed dentin was placed on the floor of cavities and sealed. After 1 month, all of the samples prepared for crown fabrication. Before crown preparation, an impression was taken in a custom tray. During crown preparation, the remnants of carious dentin were removed and undercuts were sealed by glass-ionomer. After preparation, self-cured acrylic temporary crowns were fabricated in a direct procedure and cemented permanently by glass-ionomer. One week later, teeth of the opposite jaw were prepared in a similar procedure. After 2 months, vital perfusion performed and the pulp tissue was histologically examined. Results: There was no significant difference between 4 groups, regarding to histologic status of the pulp. In healthy lower jaw, inflammation was the most frequent but in the other groups, necrosis was most frequent. Also, there was no significant difference between the upper jaw and the lower jaw groups regarding to the frequency of necrosis and inflammation. Conclusion: There is no significant difference between intact and inflamed groups regarding the frequency of necrosis and inflammation.

Live Broadcast Lectures on Complete Denture Prosthodontics at Tokyo Medical and Dental University: Comparison of Two Years

A live broadcasting system was developed as part of dental education with Information and Communication Technology (ICT) at Tokyo Medical and Dental University. The purpose of this study was to utilize this system in complete denture prosthodontics, especially for the procedure of making a definitive impression with custom tray border molding in edentulous patients, and to evaluate its effectiveness. Live broadcast lectures on complete denture prosthodontics were given to fourth-year students in 2009 (fifty-nine students) and in 2010 (sixty-five students). To evaluate this lecture, a questionnaire was distributed to the students and faculty members after the lecture. Almost all the students and faculty members rated the lecture as good. Students commented that the lecture was "intelligible," "inspiring," "improved understanding," "good because they could ask questions in real time," "helped to know the actual time," "good for all the students to see the same case," and "close to real experience and induced a sense of tension." The results of this study suggested that a live broadcast lecture would help students experience the real clinical situation and aid in teaching complete denture prosthodontics.

An In Vitro Study of the Bond Strength of Five Adhesives Used for Vinyl Polysiloxane Impression Materials and Tray Materials

Although stock trays often provide mechanical retention for elastomeric impression materials, manufacturers typically recommend the use of an adhesive, whether a stock or custom tray is used. The mention of the bond strength on the adhesive packaging is not available, therefore the clinician has no idea whatsoever of the ideal adhesive. The aim of this study was to evaluate the bond strength of three vinyl polysiloxane (VPS) materials, one with a poly(methyl methacrylate) autopolymerizing (PMMA) specimen and another with a light-polymerizing tray material (VLC), using the adhesive recommended by the manufacturer of the impression material, and two universal adhesives. A total of ninety specimens (15×15×20mm) were used, 45 specimens were made in PMMA and rest 45 was made in VLC. Five paint-on adhesives (Coltene, Caulk, 3M, universal Zhermack and universal GC) were applied. Three impression materials, Affinis, Reprosil, and 3M, were mixed and injected into a perforated poly vinyl chloride cylinder. Tray specimens were positioned against the open cylinder end in contact with the VPS material. Tensile strength tests were conducted until adhesive separation failure. Mean values and standard errors of the adhesive strength were recorded in MPa for each material combination. GC paint-on universal adhesive provided significantly higher adhesive strength values.

The effect of surface treatment and salivary contamination on the tensile bond strength between acrylic custom tray and monophase polyvinyl siloxane impression material.

Monophase elastomeric impression materials are commonly used with acrylic custom trays. Every effort is made to maximize bonding between the two. Lot of studies have focused on variables like adhesive drying time, tray material and type of elastomer but very few have solely concentrated on efficacy of surface treatment and effect of salivary contamination of the custom tray. The objective of this study was to find out the most effective surface treatment for the custom tray and also find out the extent to which salivary contamination could affect bond strengths. This invitro study was carried out in two parts using 40 samples. The materials used were Reprosil monophase impression materials and autoploymerizing acrylic blocks. The samples were divided into four groups of five samples each. The first part of the study concentrated on finding out the effect of surface treatment of the tray and the second part focused on the effect of salivary contamination. The specimens were tested in an Instron testing machine and the results of the study were interpreted by statistical analysis to arrive at the conclusions. The results showed statistically significant increase in tensile strengths for surfaces subjected to grit blasting and roughening with bur and decrease for specimens cured against wax. Salivary contamination of the tray prior to adhesive application decreased bond strengths significantly. It was concluded from the study that mechanical treatment of the tray prior to adhesive application maximizes adhesion of the impression material and that salivary contamination of the custom tray prior to adhesive application reduces adhesion between tray and elastomer regardless of the surface treatment carried out

“Grab the flab” window impression technique: A case report

Aims and objective: Making of a definitive, secondary or wash/final impression of displaceable flabby tissues with minimum or no displacement of tissue by using window impression technique. Background: Denture fabrication on flabby ridges is testing situations for a clinician as it adversely affects retention and stability of complete dentures. The difficulties encountered in these patients need to be overcome by modified techniques in denture fabrication that are not time consuming and make use of materials that are easy to use. Materials and Methods: This window impression technique, uses a custom tray with a window over flabby tissues and a mucostatic impression material to minimize distortion of tissues while making a impression. First, an accurate record of the denture supporting and limiting structures is made except for the mobile tissues which are recorded in second step using light body Polyvinyl siloxane impression material in the window area of special tray. Conclusion: The use of window impression technique helps in maintaining the contour and recording the details of the tissues without displacing the flabby tissues. Hence, it improves the prognosis for complete denture without surgical removal of hyperplastic tissues.

Oral rehabilitation of a Parkinson’s patient: A case report

Parkinson's disease is an idiopathic disorder of the central nervous system, characterized by resting tremors, muscular rigidity, slow and decreased movements. Oral rehabilitation of these patients requires special care, especially in those cases where the patient's socioeconomic status is not good and patient cannot come several times for fabrication of a complete denture. This clinical report presents a case of a Parkinson's patient who was completely rehabilitated in 3 appointments using special techniques. Border molding, final impression and jaw relation procedures were done in one appointment by using a custom tray with detachable handles and occlusal rims.

Fabrication of Customized Sectional Impression Trays in Management of Patients with Limited Mouth Opening: A Simple and Unique Approach

Impression making is not only important but is also the most significant step in the fabrication of any fixed or removable prosthesis. Proper impression making may be hindered by certain pathologic conditions. Reduced mouth opening is one of the common mechanical obstructions for proper orientation of the impression tray in the patient's mouth. In patients with trismus induced by submucous fibrosis, the procedure may be even more difficult to carry out because of reduced tissue resiliency and obliteration of vestibular spaces. Use of sectional trays offers one of the alternatives to overcome the problem of restricted mouth opening. Fabrication of customized impression trays according to the patient dentition improves the accuracy of impression making. The present case reports describe the fabrication of sectional custom trays designed for dentulous patients with chronic tobacco-induced submucous fibrosis.

Prosthodontic rehabilitation of edentulous patient with surgical induced microstomia

A restricted mouth opening which seems smaller than the size of a complete denture can make prosthetic treatment challenging. Several techniques have been described for use when either standard impression trays or the denture itself becomes too difficult to insert and remove from the mouth. This case report describes innovative techniques of primary impression, sectional custom tray, sectional denture base, and fabrication of 'customized hinge' for hinged mandibular denture.

Predoctoral Prosthodontic Curricula on Removable Partial Dentures: Survey of Turkish Dental Schools

This study was conducted to evaluate the predoctoral removable partial denture (RPD) curricula in Turkish dental schools in regards to materials, techniques, and approaches. A questionnaire consisting of eighteen multiple-choice questions was sent by e-mail to the senior members of the prosthodontic departments of seventeen long-established dental schools in Turkey. The response rate was 100 percent. All schools (100 percent) used custom trays for making final impressions of partially dentate arches, taught border molding of the custom tray for the edentulous areas, used modeling plastic impression compound in border molding the final impression trays, and used base metal alloys for RPD frameworks. None of the schools had an in-house laboratory that fabricates RPD frameworks, and none of the students cast the frameworks of their own RPDs. The majority of schools used irreversible hydrocolloid as a final impression (70.6 percent) and dental surveyor (76.5 percent) in the designing of RPDs. The majority of schools did not flask their own RPDs (64.7 percent), did not treat patients using RPDs with attachments (76.5 percent), and did not perform the altered cast technique in bilateral and unilateral distal extension RPD cases (76.5 percent). Six teen schools (94.1 percent) had a minimum number of RPD arches that a student must complete in order to graduate. It was found that predoctoral RPD curricula in Turkish dental schools were both variable and similar.

The effect of tray selection and viscosity of impression materials on the accuracy of dies produced from dual arch impressions – An in-vitro study

Objectives :The aim of this in-vitro study was to compare the accuracy of dies generated from metal and plastic dual arch trays impressions using two different viscosities of polyvinyl siloxane impression material and comparing the results to that obtained using a conventional full arch custom impression technique. Materials and method: Seven set of impressions were made of an experiment model using different combinations of, dual arch trays and viscosities of impression materials and the dimensions of the dies thus obtained were compared with those obtained from conventional full arch custom arch tray and medium viscosity impression material. Results: The gypsum dies prepared, from the complete arch custom tray technique and the dual arch impression technique using plastic and metal dual arch trays were generally larger in bucco-lingual dimension and shorter in mesio-distal dimension. Conclusions: All the seven types of impression techniques produced clinically successful impressions of standard brass die and dies so developed were within clinical standards to produced clinically successful restorations.