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PubMed1984

Comparison of the dimensional accuracy of a combined reversible/irreversible hydrocolloid impression system with other commonly used impression materials.

An investigation was conducted to compare the difference in dimensional accuracy of a combined reversible/irreversible hydrocolloid impression system and the dimensional accuracies of other commonly used impression systems. No statistically significant difference's were found between the measurements of the various materials tested and those of the master model, which leads to the conclusion that the dimensional accuracies of all the materials tested were similar. The advantages and disadvantages of each material observed during the study were reported.

Acrylic Resins↗
PubMed2006

Effect of adding impression material to mandibular denture space in Piezography.

The purpose of the study was to examine the effect of adding impression material on denture space using a piezographical record. Subjects were ten voluntary edentulous patients, aged from 61 to 84 years old. A maxillary trial denture with anterior artificial teeth and a mandibular base plate with a keel were inserted into the oral cavity. Three ml of tissue-conditioning materials was injected on the base plate for each trial. Afterwards, the patients were instructed to pronounce various phonemes, so that tongue, cheeks and lips conformed to the denture space. The impression complexes were cut at the level of the estimated occlusal plane. Occlusal analogues were made by duplicating the impression complexes. Measurements were performed for five analogues from the first to fifth additions for each subject. The data were compared using analysis of variance (ANOVA), and a Friedman's test followed by a Bonferroni test for multiple comparisons with a level of significance at 5%. At the molar and premolar positions, the bucco-lingual widths of the occlusal table increased significantly at incremental injection of impression materials from P1 to P4. The midpoints of the analogues were located at a distance of 1.5 mm buccally at the molar position and at a distance of 1.9 mm buccally at the premolar position from the top of the alveolar crest, independent of the addition of impression material. It was concluded that denture space was regulated by volume of material and was located slightly on the buccal side from the crest of the residual alveolar ridge.

Aged↗
PubMed1999

Contour determination for ovate pontics.

The ovate pontic was initially described in 1933, but was only recently considered clinically acceptable. Historically, there has been resistance to ovate pontics, but this resistance lacks scientific and biologic evidence to justify rejection. Explicit instructions are mandatory for predictable results from dental laboratories. This article describes a method for communicating exact dimensions for an ovate pontic that was previously contoured for a patient in a provisional restoration to ensure clinical and histologic success. Polyvinyl siloxane putty is suggested as a matrix material for the predetermined contour. An esthetic and functional restoration will result when these materials and procedures are used in an appropriate sequence.

Attitude of Health Personnel↗
PubMed1985

Automixing: a new concept in elastomeric impression material delivery systems.

Automixing of impression materials has been shown to reduce or eliminate many of the problems associated with spatula-mixing. Contamination is prevented, voids are eliminated, and physical properties are comparable to those of spatula-mixed materials. These advantages in combination with the desirability of the system should ensure its success and further development.

Air↗
PubMed2005

Indirect latex glove contamination and its inhibitory effect on vinyl polysiloxane polymerization.

STATEMENT OF PROBLEM: The inhibitory effect of indirect latex contamination on the polymerization of vinyl polysiloxane (VPS) impression material has been previously reported. However, the transfer of specific elements that cause inhibition has not been confirmed, nor has the removal of such contaminants been reported. PURPOSE: This study examined the surfaces of materials commonly used in restorative procedures that were contaminated by indirect latex glove contact and then evaluated for inhibition of polymerization of VPS. The effect of selected cleansing procedures was then studied. MATERIAL AND METHODS: Four experimental groups (n = 8) were prepared: (1) clean vinyl gloves (control), (2) clean gingival retraction cords (control), (3) contaminated vinyl gloves, and (4) contaminated gingival retraction cord. Microscopic evaluation of the appearance and the characterization of surface particulate contamination were performed for each. Three cleansing protocols were then evaluated for efficacy in cleaning vinyl glove surfaces contaminated by latex contact (n = 10): (1) brushing with water, (2) brushing with soap/rinsing with water, (3) cleansing with rubbing alcohol. The subsequent degree of VPS polymerization inhibition was evaluated subjectively. A chi-square test was used for data analysis (alpha=.05). RESULTS: Particulate sulfur elements and sulfur-chloride compounds were present on the contaminated substrates. None of the 3 cleansing procedures eliminated polymerization inhibition (P =.33). Residual elemental sulfur remained on all tested surfaces. CONCLUSION: Particulate sulfur and sulfur-chloride compounds were identified as the particulate contamination that resulted in polymerization inhibition of the tested VPS dental impression material. Removal of these contaminants from the tested vinyl gloves and gingival retraction cord was not possible with the 3 cleansing protocols tested in this study.

2-Propanol↗
PubMed1989

Evaluation of the methods for dislodging the impression tray affecting the dimensional accuracy of the abutments in a complete dental arch cast.

The dimensional accuracy of dies was evaluated in complete dental arch casts made by three different methods of dislodging the impression tray. By one method, the impression tray was dislodged parallel to the long axis of the abutment and by the other two the trays were inclined with the fulcrum at either the posterior or anterior region of the complete dental arch. The dimensional changes of the molar-die were significantly affected by the dislodging method in the inclined way but not those of the incisor-die. The anteriorly inclined method showed fewer dimensional changes than the posteriorly inclined method. On the other hand, the dimensional changes of the incisor-die were not significant by any dislodging method, but were observed when some impression material was used. If the impression tray is removed by the inclined way, the fulcrum should be chosen at a region remote from the abutment instead of at the proximal region.

Calcium Sulfate↗
PubMed1993

Inhibition of polymerization of polyvinyl siloxanes by medicaments used on gingival retraction cords.

Inhibition of polymerization of polyvinyl siloxane materials by latex products is well documented. It is thought to be caused by contamination of the chloroplatinic acid catalyst by sulfur compounds. Many medicaments, such as aluminum sulfate and ferric sulfate, used on gingival retraction cords have been accused of causing inhibition of set of polyvinyl siloxane materials. Several of these medicaments were tested with two polyvinyl siloxanes and found not to cause any inhibition of set.

Alum Compounds↗
PubMedDate not supplied

Accuracy of implant impression techniques.

Three impression techniques were assessed for accuracy in a laboratory cast that simulated clinical practice. The first technique used autopolymerizing acrylic resin to splint the transfer copings. The second involved splinting of the transfer copings directly to an acrylic resin custom tray. In the third, only impression material was used to orient the transfer copings. The accuracy of stone casts with implant analogs was measured against a master framework. The fit of the framework on the casts was tested using strain gauges. The technique using acrylic resin to splint transfer copings in the impression material was significantly more accurate than the two other techniques. Stresses observed in the framework are described and discussed with suggestions to improve clinical and laboratory techniques.

Acrylic Resins↗
PubMed1987

Improving reversible hydrocolloid impressions of subgingival areas.

The causes usually given for not having success with reversible hydrocolloid are that the impression material that goes beyond the subgingival margins often tears on removal and that the syringe material sets too fast. Both of these problems can be overcome and an extremely high rate of success can be obtained by following the technique described.

Chemical Phenomena↗
PubMed1989

The detection of cavitation in carious approximal surfaces in vivo by tooth separation, impression and scanning electron microscopy.

Bitewings are the most effective method of detecting approximal lesions but correlation with surface integrity is poor. In this study teeth were separated using orthodontic elastic separators allowing impressions, taken in a vinyl polysiloxane impression material, to be viewed by scanning electron microscopy. Case reports demonstrate the effectiveness of this technique in assessing in vivo, and in detail, the extent of cavitation of lesions usually assessed by their radiographic image alone.

Adolescent↗
PubMed1991

A comparison of impression materials for complete-arch fixed partial dentures.

This study compared the marginal fit of complete-arch fixed prostheses under simulated clinical conditions. Prostheses were made on casts constructed from three commonly used impression materials; polyether, polyvinyl siloxane (medium-viscosity and putty-wash), and reversible hydrocolloid. A maxillary dentoform with four abutment teeth was used as the master cast and six impressions were made with each material. Individual castings for each abutment were made on the stone casts. The abutment castings were luted together on the casts to provide a complete-arch fixed partial denture using a ticonium framework and acrylic resin. The marginal fit of the abutment castings was measured on the master cast before and after the prostheses were luted together. The polyether and both addition silicone impression materials were significantly more accurate than the reversible hydrocolloid in both situations. All of the single castings were clinically acceptable, but the luted restorations made from reversible hydrocolloids were not.

Analysis of Variance↗
PubMed1997

Marginal fidelity of crowns fabricated from six proprietary provisional materials.

STATEMENT OF PROBLEM: The most important requirement for an interim crown is suitable marginal adaptation. PURPOSE: This in vitro study compared vertical discrepancies of margins for complete crowns made with six provisional materials (Provipont, Protemp Garant, Unifast LC, Triad VLC, Splintline, and Jet). MATERIAL AND METHODS: A direct technique was used to fabricate 60 provisional complete crowns on prepared molars with a polyvinyl siloxane impression and a vacuum-formed polypropylene sheet as matrices. A measuring microscope was used to measure vertical marginal discrepancies at x 100. Data were analyzed with Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests (alpha = 0.05). RESULTS: Significant differences were found between resinous materials tested (p = 0.0002) and multiple comparisons tests indicated no significant difference between Splintline and Protemp Garant; Provipont, Unifast LC, and Triad VLC; and Unifast LC, Triad and Jet provisional materials. CONCLUSIONS: This study indicated that provisional crowns fabricated with Splintline and Protemp Garant interim restorative materials recorded the least marginal discrepancies.

Acrylic Resins↗
PubMed2003

Influence on dimensional accuracy of volume of wash material introduced into pre-spaced putty/wash impressions.

This study compared the accuracy of stone models obtained from two-stage, pre-spaced putty/wash impressions under conditions in which known volumes of wash material were introduced during the second stage of the impression: Group I, a quantity of wash material corresponding to the space provided; Group II, double the quantity of wash material as the space provided; Group III, double the quantity of wash material, but with V-shaped vents in the putty for escape of excess material. Percentage deviations of the vertical dimensions of stone dies with respect to the master model were significantly different between Groups I and II (the latter being shorter) (p < 0.05). For horizontal dimensions, differences were less consistent, although the deviations for Groups I and II and Groups II and III, with respect to the master model, were significantly different from each other for two of the three dimensions measured (Group II inter-abutment distances were generally larger) (p < 0001 and p < 0.05, respectively). It is concluded that putty recoil, resulting from compression by excess wash material, plays a significant role in the undersizing of working dies, although the level of clinical relevance is less clear.

Dental Impression Materials↗
PubMed2001

"Function" with registration: simple, fast, and safe using a new registration material.

Although the Function construction method with Cerec 2 always remained a method for enthusiastic experts, Cerec 3 enables the practiced "normal user" to use this method expediently. With the new R-Sl-LINE Metal-Bite registration material, an important step towards accelerating the process has been taken by eliminating a powder sequence and by its fast curing. Due to the special definition properties of the material, including the antagonist situation in the design of the occlusion has become considerably more reliable.

Computer-Aided Design↗
PubMed1980

Impression materials and techniques used for cast restorations in eight states.

In a survey of dentists practicing in eight states, it was found that polysulfide is used by 35.8% of them for cast restorations. Polyether and hydrocolloid are the second most used materials; silicone putty/reline and double mix standard silicone follow. Epinephrine cord was chosen for gingival retraction by 73.3% of the respondents. Nonepinephrine cord is used by 23.5% of the dentists who responded.

Administration, Topical↗