Light-bodied Impression Material Research Articles

In Vitro Handling Characteristics of a Particulate Bone Substitute for Ridge Preservation Procedures.

While particulate bone substitute materials are applied in a variety of augmentation procedures, standardized defects are being used for preclinical testing. This in vitro study evaluated the density and homogeneity of a particulate bone substitute in ridge preservation procedures. Premolars and molars were extracted in ten semimandibles of minipig cadavers. Light body impression material was used for determining the volume of the extraction sites followed by augmentation with particulate material, thereby weighing the graft material needed. Microradiographs and histologic sections were obtained for evaluating the homogeneity and density of the augmentation material. Statistical analyses were based on Shapiro-Wilk tests, Spearman's rho and one sample Wilcoxon test followed by Bonferroni-Holm correction for multiple testing (α = 0.05). Based on 103 single alveoli evaluated, the mean volume determined was 0.120 cm3 requiring a mean amount of graft material of 0.155 g. With only three exceptions, all parameters (volume, mass of augmentation material, density and homogeneity) correlated significantly (p < 0.020). The apical parts of the alveoli showed reduced density as compared to the middle parts (p < 0.001) and the homogeneity of the augmentation material was also lower as compared to the middle (p < 0.001) and cervical parts (p </= 0.040). The packing of augmentation material is critical when non-standardized defects are treated.

An in vitro comparison of fracture resistance of immature teeth subjected to apexification using three different bioactive materials

To compare the fracture resistance of immature teeth subjected to apexification with three different bioactive materials. Sixty non-carious, single-rooted premolar teeth with straight canals were decoronated at cementoenamel junction, standardizing 13 mm length. After access preparation, the canals were accessed with #10 K-file followed by biomechanical preparation using Ni-Ti ProTaper Gold rotary files upto F3 and irrigation was done using 2 mL 3% NaOCl, 17% EDTA and 5 ml of saline. To simulate immature roots with open apices, #1–5 Peeso reamers were passed through the apex enlarging to 1.5 mm diameter. Later, samples were randomly divided into 4 different groups with 5mm apical plug in each group, Group I: GuttaFlow Bioseal, Group II: Biodentine, Group III: EndoSeal MTA and Group IV: Control group. Samples were filled with an apical plug of 5mm. Later, remaining part of the root canals was obturated with gutta-percha cones and AH Plus sealer by lateral condensation. To stimulate periodontal ligament lining of the root surfaces, C-Silicone light body impression material was used. The samples were stored for 1 week in 100% humidity at 37˚C to ensure that the sealer set in an environment that simulate the clinical situation. Later, fracture resistance was evaluated using the universal testing machine. Group II (Biodentine) showed highest fracture reisistance followed by Group I (GuttaFlow BioSeal) and Group III (EndoSeal MTA) Biodentine apexification groups showed highest fracture resistance values followed by GuttaFlow Bioseal and the least values were shown by EndoSeal MTA.

Comparative Evaluation of Wettability at Various Stages of Working Time for Light Body and Medium Body Consistencies of Three Elastomeric Impression Materials.

Aim:The main purpose of this study was to compare the wettability of light and medium body consistencies of three different elastomeric impression materials during their working time.Materials and Methods:Vinylpolysiloxane, polyether, and vinylsiloxanether light body and medium body impression materials were used to fabricate the test samples. The contact angles of the impression materials were determined at 30th s from the start of mixing until their entire range of working time using a goniometer. The mean contact angles at the early stage of working time and at the end of working time for two consistencies of each impression material were subjected for statistical analysis.Results:The result showed contact angle of all the impression materials toward the end of working time was less than the early stage with the statistical significance (P < 0.05). The contact angle of the light body impression material was less than the medium body impression materials with statistical significance (P < 0.05) except for vinylsiloxanether impression material.Conclusion:We have concluded from this study that vinylsiloxanether impression materials exhibited the least contact angle followed by polyether and the highest was recorded for vinylpolysiloxane impression material.

Comparison of the Fit Accuracy of Hybrid Ceramic Prostheses Generated By Three CAD-CAM Systems.

Background: Marginal and internal fit are believed to be one of the most important guideline in the assessment of ceramic restorations and are one of the most remarkable requirement for the long-term performance of fixed dental prostheses. PURPOSE: Was to evaluate the influence of different CAD-CAM systems on the marginal and internal adaptation of hybrid ceramic restorations. Materials and Methods: Lower right six of a typodont resin cast with a 1.0 mm circumferential chamfer finish line, an occlusal reduction of 2.0 mm, and an average of 10-12° convergence angle was prepared. This master die was duplicated to thirty acrylic resin dies milled from PMMA discs using CAD-CAM technique. Vita Enamic monolithic crowns were manufactured using three different CAD-CAM systems Ceramill, Zirkonzahn and CEREC InLab systems (n=10). Replica technique procedure was used to assess marginal and internal fit of the fabricated prostheses by measuring the thickness of light body impression material between the master die and the restoration at five points using digital microscope. Results: Measurements were collected for each group and appropriate statistical analysis was carried out. Conclusion: CEREC system showed relatively lower marginal and internal discrepancy in a comparison with the other systems. Therefore, there is a significant difference among the three systems.

Dual-space technique for creating cement space in a cementation device for implant dentistry: A predictable chairside approach

As residual excess cement in peri-implant tissues is a problem that can lead to implant failure, great care must be taken when delivering cement-retained crowns. Cement selection, prosthetic design, and cementation techniques can reduce the chances of having excess cement in peri-implant tissues. Multiple techniques have been described, but, in many, the cement space has been reproduced by unreliable means. The dual-space technique allows the clinician to fabricate an implant crown delivery device in which the cement space has been replicated in a predictable and straightforward manner. In this technique, light-body impression material is used to create the luting space before the fabrication of the device with bis-acryl resin.

Evaluation of effects of porcelain firing on the marginal fit changes of porcelain–fused-to -metal crown fabricated utilizing two different margin designs and two commercially available base metal alloys

Aim: To find the marginal fit of the porcelain fused to metal crowns by two different margin designs (shoulder and chamfer) and two commercially available base metal alloys.Material and Methods: Tooth preparation of first central incisor for porcelain-fused-to-metal crown with shoulder margin and second incisor for porcelain-fused-to-metal crown with chamfer margin was done. Wax pattern of the same was prepared. Impression of both prepared ivorine incisors was made by light body impression material and poured with pattern resin. Both the patterns were invested and casted with cobalt chromium alloy for making master dies. Two wax patterns of unprepared central incisors were fabricated, one with shoulder margin and another with chamfer margin. These patterns were then cut back to the size of the coping. Four rings were invested. In each ring ten patterns, five with shoulder margin and five with deep chamfer margin were sprued together to ensure that each group would pass through the same investing and casting procedure, followed by ceramic firing and measurement.Results: Marginal fit change or marginal discrepancy (before and after firing) between the groups was highly significant.Conclusions: Veneered crowns exhibited highly significant marginal distortion than non- veneered copings after porcelain firing. Shoulder margin is better in minimizing marginal discrepancy compared to deep chamfer margin. Marginal discrepancy is less when cerabond base metal alloy is used with shoulder margin as compared to commend base metal alloy used for shoulder margin.

Effect of imaging powder and CAD/CAM stone types on the marginal gap of zirconia crowns

ObjectiveTo compare the marginal gap using different types of die stones and titanium dies with and without powders for imaging. MethodsA melamine tooth was prepared and scanned using a laboratory 3-shape scanner to mill a polyurethane die, which was duplicated into different stones (Jade, Lean, CEREC) and titanium. Each die was sprayed with imaging powders (NP, IPS, Optispray, Vita) to form 15 groups. Ten of each combination of stone/titanium and imaging powders were used to mill crowns. A light-bodied impression material was injected into the intaglio surface of each crown and placed on the corresponding die. Each crown was removed, and the monophase material was injected to form a monophase die, which was cut into 8 sections. Digital images were captured using a stereomicroscope to measure marginal gap. Scanning electron microscopy was used to determine the particle size and shape of imaging powders and stones. ResultsMarginal gaps ranged from mean (standard deviation) 49.32 to 91.20 micrometers (3.97-42.41 μm). There was no statistical difference (P > .05) in the marginal gap by any combination of stone/titanium and imaging powders. All of the imaging powders had a similar size and rounded shape, whereas the surface of the stones showed different structures. ConclusionsWhen a laboratory 3-shape scanner is used, all imaging powders performed the same for scanning titanium abutments. However, there was no added value related to the use of imaging powder on die stone. It is recommended that the selection of stone for a master cast be based on the physical properties. Practical ImplicationsWhen a laboratory 3-shape scanner is used, the imaging powder is not required for scanning die stone. Whenever scanning titanium implant abutments, select the least expensive imaging powder.

Dimensional Accuracy of Two-Step Impressions Measured on Scanned Casts in CAD

The purpose of the study was to find out how light-body impression material thickness influences the horizontal dimensional accuracy of casts examined on a scanned model. Customized manikin mandibles were used for impression taking with a dual-phase impression method. These mandibles were prepared in a way that allowed the control of light-bodied impression material thickness. First premolars were prepared for a full crown by supragingival chamfer on both sides in all mandibles. For the measurements, buccal and lingual reference points were made at the preparation margin. Impressions were taken at nine thickness levels and a control level (TTotal = 10; 0-1.2 mm), and the reference points' average distance was compared across thickness levels on both the left and right side. We carried out three measures for each specimen and used three specimens per thickness level. Total sample size was N = 180, creating a sizable database to understand the influence. The results indicated that light-body impression material thickness had no influence on the horizontal dimension of a die measured on scanned dies in these specific circumstances. The thickness of light-body impression material in the dual-phase impression taking technique did not have a significant influence on the horizontal accuracy of scanned dies, which makes the technique safe and reliable for single crown restorations without having to take extra precautions for the thickness of light-body impression material.

Two‐step impression for atrophic mandibular ridge

The clinical difficulties encountered while treating edentulous patients with atrophic mandibular ridges are legion. Capturing tissue details while making an impression of a resorbed mandibular ridge poses a great clinical challenge. Extending the denture bases adequately to cover all of the available supporting tissues is one of the prime requisite. Surgical approach is necessary only when the patient is incapable of wearing a conventional denture. This article describes a technique of making an impression of an atrophic mandibular ridge by the use of monophase and light-bodied impression material where surgical options such as implants, vestibuloplasty or ridge augmentation may not be feasible. This procedure results in improved stability and retention of the denture base.

Efficacy of various materials in recording enamel rod endings on tooth surface for personal identification

Aim:To analyze efficacy of cellulose acetate film, cellophane tape, and light body impression material in recording enamel rod endings on tooth surface for personal identification.Materials and Methods:Surface enamel rod endings of 30 extracted teeth were recorded from the same area of the same tooth for two times using cellulose acetate film, cellophane tape, and light body impression material. Photomicrographs of enamel rod endings were taken and subjected to Verifinger standard SDK version 5.0 software for analysis. Minutiae scores of all enamel rod end patterns obtained using these three imprint materials were statistically analyzed.Results:Cellulose acetate film imprint showed complete enamel rod end patterns and the software was able to identify the particular tooth with the same previous identification number in subsequent recordings as well. Cellophane tape and light body rubber-base impression material imprint showed incomplete enamel rod end patterns and the software failed to identify the particular tooth with the same previous identification number in subsequent recordings. Statistical analysis revealed that cellulose acetate film recorded more number of minutiae points compared with the other imprint materials.Conclusion:Cellulose acetate film is a reliable material for recording enamel rod endings on tooth surface for personal identification compared with cellophane tape and light body rubber-base impression material.

A clinical pilot study of the dimensional accuracy of double-arch and complete-arch impressions

Statement of Problem. It has been suggested that articulated casts fabricated with the double-arch impression technique may have superior occlusal accuracy than those fabricated with a single complete-arch impression. However, lack of tray rigidity may lead to flexure of the impression/tray complex, resulting in inaccurate dies in the bucco-lingual dimension. Purpose. This clinical pilot study compared the dimensions of dies fabricated with 3 types of double-arch impressions to dies fabricated with the conventional complete-arch, custom tray method. Material and Methods. Thirty-five addition silicone impressions were made of cast metal copings cemented onto natural teeth prepared as complete-crown abutments. Four combinations of tray types and impression material viscosity were used: (1) complete-arch, custom acrylic trays loaded with heavy-bodied material; (2) double-arch, disposable plastic trays loaded with heavy-bodied material; (3) double-arch, disposable plastic trays loaded with putty material; and (4) double-arch, reusable brass metal trays loaded with heavy-bodied material. Immediately prior to tray insertion, light-bodied impression material was syringed over all copings as a wash. The 4 copings were fabricated from cast gold and simulated metal-ceramic complete-crown thimbles with polished collars and had “projections” on the occlusal surfaces. The impressions were poured in type IV die-stone. Bucco-lingual and inter-abutment dimensions were measured. The differences between the stone dimensions and cast metal control dimensions were calculated and converted to percent dimensional change. The data were analyzed with 1-way analysis of variance, Student t tests, and Mann-Whitney tests (P<.05). Results. The plastic double-arch tray loaded with heavy-viscosity addition silicone and a low-viscosity wash produced the least accurate combination inter- and intra-abutment dimensions. For this protocol, 1.17% mean dimensional change was recorded. This result was significantly different than that obtained for the other 3 impression methods tested. No significant differences were found between the complete-arch method and protocols in which putty was loaded in a plastic or metal tray. Conclusion. Within the limitations of this pilot study, the more rigid tray/impression material combinations more accurately replicated stone dies. (J Prosthet Dent 2002;87:510-5.)

Panasil light body impression material study

SummaryThis study was undertaken to confirm that Panasil light body is a suitable replacement impression material for Panasil ‘C’, used for ocular impression procedures, which was withdrawn by the manufacturers in 1993. The damaging effects to the corneal and conjunctival tissues of alginate materials used in the past during impression‐taking procedures for artificial eye and cosmetic shell prostheses, is recognized by ocularists and optometrists.Modern silicone impression materials demonstrate:1. Minimal disruption to tissues.2. High accuracy.3. High strength in relation to thin section.4. Good flow characteristics prior to curing.Panasil light body impression material is polyvinyl siloxane based, low viscosity, addition curing silicone.Our trial investigated the effects of obtaining impressions from five groups of patients presenting with:1. Anophthalmia with hydroxyapatite implants.2. Phthisical eyes.3. Unsighted vascularized eyes.4. Clear corneas.5. Exenterated orbits with osseointegrated implants.Total number of patients examined was 30.In all cases where an eye was present, post‐procedural examination by Burton/slit‐lamp with fluorescein was carried out to determine the level of tissue damage/abrasion. A table of results is presented.We have shown that Panasil light body silicone impression material is accurate and stable when used for the purposes investigated. We would emphasize the minimal adverse effects to the corneal and conjunctival tissues observed during the course of this study.

Panasil light body impression material study

Summary This study was undertaken to confirm that Panasil light body is a suitable replacement impression material for Panasil ‘C’, used for ocular impression procedures, which was withdrawn by the manufacturers in 1993. The damaging effects to the corneal and conjunctival tissues of alginate materials used in the past during impression-taking procedures for artificial eye and cosmetic shell prostheses, is recognized by ocularists and optometrists. Modern silicone impression materials demonstrate: 1. Minimal disruption to tissues. 2. High accuracy. 3. High strength in relation to thin section. 4. Good flow characteristics prior to curing. Panasil light body impression material is polyvinyl siloxane based, low viscosity, addition curing silicone. Our trial investigated the effects of obtaining impressions from five groups of patients presenting with: 1. Anophthalmia with hydroxyapatite implants. 2. Phthisical eyes. 3. Unsighted vascularized eyes. 4. Clear corneas. 5. Exenterated orbits with osseointegrated implants. Total number of patients examined was 30. In all cases where an eye was present, post-procedural examination by Burton/slit-lamp with fluorescein was carried out to determine the level of tissue damage/abrasion. A table of results is presented. We have shown that Panasil light body silicone impression material is accurate and stable when used for the purposes investigated. We would emphasize the minimal adverse effects to the corneal and conjunctival tissues observed during the course of this study.