A New Simplified Beading and Boxing Procedure for Elastic Impression

Beading and Boxing of impression is taught in most dental colleges. The boxing procedure is crucial step to preserve the details of the final impression especially of the vestibular area. This article describes an alternative beading-boxing procedure that is compatible with all impression materials, is efficient, simple, inexpensive, and practicable. Use of commercially available instant adhesive around the border to act as a joining agent between elastic impressions and beading wax or bead made up of base plate wax is advocated in this technique.     

Preformed Beading and Boxing Appliance

Conventional beading and boxing procedure is time consuming and involves application of heat that might distort green stick compound used for border molding. Earlier studies regarding beading and boxing methods have shown usage of various materials that were disposable and that cannot be recycled. To reduce the time consumed for beading and boxing procedure and to make this procedure cost-effective by using recyclable beading material, “Preformed boxing appliance” with moldable clay meant for beading the secondary impression was used. Secondary impression was supported by 3 studs provided on the floor of the boxing appliance. The cast was poured. The duration for the entire procedure was much less than the conventional procedure.     

Technique for making flexible impression trays for the microstomic patient

This impression technique can be used for patients in whom routine use of stock impression trays is hindered by microstomia. Putty wash material can be manipulated with minimal effort and time. Placing the completed preliminary impression in a free-flowing mix of dental stone stabilizes the impression material and facilitates boxing and pouring of the impression. The resultant preliminary casts can then be used for diagnostic purposes and for making rigid sectional trays for final impressions.     

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A technique has been described for utilizing polyether interocclusal registration material in place of utility wax to form a border prior to boxing an impression. The material is simple to use, readily adheres to the impression size and shape, and can be used with polyether as well as vinyl polysiloxane impression materials. (The adhesive supplied with the vinyl polysiloxane must be used with that material.)     

Full band impressions

Complete impression with rings achieves the same definition than complete impressions alone and gives a final quality similar to unitary guided impressions. The required steps are the following: 1st clinical: adjustment of the unitary rings, laboratory: elaboration of metallic resin boxing and individual tray, 2nd clinical: complete impression with rings. This method is of a particular interest because of its facility and its possible adaptations to various impression pastes or clinical situations. No gingival conditioning is required to the impression, and increased indications of the method can thus be seen when esthetics or periodontal conditions are a priority.     

The Results of a Brief Survey of Complete Denture Prosthodontic Techniques in Predoctoral Programs in North American Dental Schools

A brief mail survey of North American dental schools was undertaken to ascertain the current techniques in complete denture prosthodontics regarding preliminary and final impressions, record bases, and denture teeth. Of the 64 schools surveyed, 54 responded (84%). Seventy-four percent of the respondents used only irreversible hydrocolloid (alginate) for their preliminary impressions; 15% used only modeling plastic impression compound. Eighty-one percent used only modeling plastic impression compound for border molding of the final impression tray; 7% used only polyether impression material. Forty-eight percent used only polysulfide rubber (PR) impression material for their final impression material; 4% used only polyether impression material. Only 1 school still used shellac as one of its materials for record bases. Thirty-five percent used only Triad; 35% used only acrylic resin; 24% used both of these materials. Thirteen percent of responding schools used only nonanatomic teeth. The majority (54%) used all three options (nonanatomic, semianatomic, and anatomic). Eleven percent used lingualized occlusion. As compared with a survey performed in 1985, the use of irreversible hydrocolloid as a preliminary impression material, the use of visible light-cured resins for record bases, and the use of anatomic teeth have increased. The use of plastic impression compound for border molding and PR as the final impression material has largely remained the same.     

Universal paradigms for predictable final impressions

The master blueprint for indirect restorations is the final impression. The challenge for the clinician is to establish a protocol that ensures a predictably excellent final impression.The purpose of this article is to provide a protocol that integrates the many detailed steps of impression making, from patient comfort to dental laboratory communication. Understanding the biology of the dentogingival junction, dental materials and their interactions, and proper technique all contribute to the final results.     

A simple method of boxing rubber base impressions

The advantages of boxing an impression are better adaptation of stone around dowel pins, control over the level of the second pour of stone, and minimal cast trimming. This article describes a simplified boxing technique that offers the following additional advantages: Parts of the impression that are inadequate in length can be extended to ensure a die of adequate length (Fig. 6). Boxmat adheres to the rubber base and facilitates application. Contouring the palatal or lingual part of the impression is greatly simplified and provides access for sawing out dies. The material is reusable.     

A predictable and accurate technique with elastomeric impression materials

A method for obtaining more predictable and accurate final impressions with polyvinylsiloxane impression materials in conjunction with stock trays is proposed and tested. Heavy impression material is used in advance for construction of a modified custom tray, while extra-light material is used for obtaining a more accurate final impression.     

Current concepts and techniques in complete denture final impression procedures

PURPOSE: In 2001, a survey of U.S. dental schools was conducted to determine which concepts, techniques and materials are currently prevalent in the teaching of final impression procedures for complete dentures in the predoctoral clinical curriculum. MATERIALS AND METHODS: The questionnaire was mailed to the chairperson of the prosthodontic/restorative departments of 54 U.S. dental schools. Of these, 44 schools returned the completed survey resulting in a response rate of 82%. RESULTS: Results from this survey show that the majority of schools (71%) teach the selective-pressure technique for final impression making; the majority of the schools (64%) use modeling plastic impression compound for border molding the final impression tray; 39% of the schools do not place vent holes in the final impression tray, 30% of schools place more than one hole and 27% place one hole only; the majority of the schools (98%) are using custom trays for final impressions. Ninety-eight percent of the schools are border molding the custom tray and 70% of schools are using a visible light-cured (VLC) composite resin material to make the trays. Thirty-six percent of the schools are teaching the Boucher impression technique and 34% are teaching the modified Boucher impression technique. CONCLUSIONS: Predoctoral clinical complete denture educational programs agree on many aspects of final impression making, however, there is variability in their teachings regarding the impression philosophy and the materials used.     

Application times for the single-step/double-mix technique for impression materials in clinical practice

Hydrophilicity of unset impression materials underlies changes occurring during working time. Hence, the clinical application time when impression materials contact oral tissues after mixing may play a critical role in successful impressions. The aim of this study was to analyze the clinical time course of impression taking applying the single-step/double-mix technique. Application times of 86 impressions, comprising 265 prepared teeth and 46 implants, taken by 14 different clinicians at a university dental clinic were analyzed. The mean time from loading the impression tray until its final position in the patient's mouth (total application time) was 51.2 seconds; confidence intervals were 46.9 (lower limit) and 55.5 (upper limit). The number of registered teeth and implants did not influence the duration of impression taking. Related to wettability data, several polyvinyl siloxane impression materials show decreased hydrophilicity with respect to estimated application times. The authors suggest considering clinically relevant application times for impression taking in future in vitro studies on physicochemical characteristics of impression materials.     

Medium-viscosity polyether impression material: a case report

Polyethers are elastomeric materials commonly used for making precision impressions. They are hydrophilic, which facilitates the contact of the unset material with the intraoral tissue and the wetting of the impression by cast materials. The final hardness of this new impression material is reduced in an attempt to overcome rigidity of the set impression. A case is described involving the restoration of a fractured maxillary premolar and a single-phase impression technique using the new polyether impression material.     

An implant-retained auricular impression technique to minimize soft tissue distortion

Achieving adaptation of an auricular prosthesis begins with an accurate impression. It is important to consider how the selection of the impression materials will affect the final outcome of the prosthesis. A procedure is presented to minimize the distortion of the soft tissues caused by the impression materials and procedure. The procedure consists of splinting the implant impression copings, then recording the soft tissue in silicone impression material, followed by the application of acrylic tray resin to provide rigidity.     

A functional open-tray impression technique for implant-retained overdenture prostheses

Several implant impression techniques with different materials have been described in the literature. Generally, border molding, functional, and final impressions have been made with 3 different materials, which makes the procedure technique-sensitive and time-consuming. A combination of open-tray and functional impression techniques is described in this technical report. Border molding and functional impression procedures are made at the same time using a vinyl polysiloxane impression material, which makes this technique a simple and time-efficient alternative for clinicians.     

A boxing technique for making moulages of facial defects

A technique using irreversible hydrocolloid in conjunction with conventional boxing method is described for making impressions of facial defects. The technique improves control of impression material without causing distortion of soft tissue adjacent to facial defects.     

全口义齿印模技术的发展现状

全口义齿修复前,需通过可塑性印模材料来复制无牙颌牙槽嵴和周围软硬组织的解剖形态,清晰准确的口腔印模不仅为后续技工制作义齿提供了良好的结构基础,而且是保证最终修复体固位、稳定及功能的关键.现有研究表明,除印模材料、印模托盘、印模操作和印模消毒外,印模技术也是无牙颌印模制取精度的重要影响因素之一.近年来,随着各类牙科材料的...     

The study on surface porosity of die stone. Influence of vinyl polysiloxane impression materials

In this study, the authors have attempted to discover optimum conditions for eliminating all porosity, except what is caused by manual error, in the surfaces of Die Stone. Five vinyl-porisiloxane impression materials, two other kinds rubber impression materials, and two kinds of die materials were used. Die materials were poured at intervals of 0, 15, 30, 60, and 120 minutes after the impression had been removed. Cast-surface porosity was measured by means of SPICCA II. Results 1. Practically surface porosities were not scarcely observed in casts made from any of the impression materials except vinyl silicone rubber. Among the five vinyl-polysiloxane impression materials, Hydrophilic Exaflex produced the least porosity. 2. Porosity in casts made with Provil tended to decrease definitely as pouring time progressed. This tendency occurred with no other materials. 3. When the die material was mixed at a low water-powder ratio, cast-surface porosity was reduced in the case of all materials except President. 4. Concentration of hydrogen gas, which was released from all vinyl-polysiloxane impression materials, decreased with the passing of time. 5. In the case of Provil, a correlation existed between hydrogen-gas concentration and the degree of cast-surface porosity. But no similar correlation was observed in the case of any other vinyl-polysiloxane impression materials.     

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口腔印模的质量直接影响修复体的准确性和修复质量。临床常用的口腔弹性印模材料有藻酸盐水胶体印模材料、琼脂水胶体印模材料、硅橡胶印模材料、聚醚橡胶印模材料和聚硫橡胶印模材料。各种材料组成不同,性能各异,临床使用时应根据具体病例,选择合适的印模材料和消毒方法,以获取最佳效果。本文主要介绍了各弹性印模材料性能特点及临床使用注意事项。     

Final impressions: a review of material properties and description of a current technique

Esthetic rehabilitations are characterized by a sequence of well-structured clinical and laboratory steps, during which different kinds of impressions are required. This review presents a survey of the most clinically relevant physical properties that characterize final impression materials and their interactions with the products they are commonly in contact with. The principal steps of an esthetic rehabilitation involving a diagnostic phase, together with a rational step-by-step approach to final impressions, are described. The one-step/double-mix impression using polyvinyl siloxane materials associated with a "double cord" gingival displacement is explained.     

Compatibility of Type IV Dental Stones With Polysulfide Impression Materials

PURPOSE: In the American National Standards Institute/American Dental Association specification no. 19, compatibility of impression materials with dental stones is assessed by the presence of a 20-microns-wide line reproduced on an unmodified calcium sulfate dihydrate cast. In actual dental practice, modified type IV dental stones are used, although little is known of their compatibility with polysulfide impression materials. This study evaluated the compatibility of 6 polysulfide impression materials and 11 modified type IV dental stones. MATERIALS AND METHODS: A line 20 microns wide was etched on four glass dies. Four samples of each combination of impression material and dental stone were prepared according to the manufacturer's directions with an additional 3 minutes for the final setting time. Compatibility was determined by the presence of the reproduced line on the dental stones, as observed under low angle 10 x magnification by four rater groups. RESULTS: The line was reproduced on all of the impression specimens, and the examiners recorded 66 positive identifications of the line on the stone casts out of a possible 1,056 ratings for a total of 6.25% of the specimens. Out of a possible 66 impression-stone combinations, only 18 reproduced the 20-microns line. The combinations reproducing the lines most frequently (75%) were Neoplex with Blue Die Stone (Columbus Dental, St Louis, MO) and Coeflex with Indic Die Stone (Coe Lab Inc, Chicago, IL). CONCLUSIONS: The study showed that many combinations of polysulfide impression materials and modified type IV dental stones did not reproduce the 20-microns line; therefore, not every polysulfide is compatible with every type IV dental stone.