Dimensional stability of stored extended-pour irreversible hydrocolloids materials

The purpose of this study was to evaluate the linear dimensional stability of four extended-pour irreversible hydrocolloids (EPIHs). Material and Methods: Five samples per material (Cavex ColorChange, Cavex Orthotrace, Jeltrate Plus, and Orthoprint) were prepared following the manufacturers’ instructions. The samples were prepared using a cylindrical matrix coupled with a nylon-polyamide ring. Two parallel, 25-mm equidistant lines were made on its surface following ANSI/American Dental Association (ADA) Specification 18 for plaster reproducibility and compatibility and Specification 19 for linear dimensional change. The samples were stored in an environment with a relative humidity of 70% (± 3) and temperature of 28°C (± 2). Photo images were obtained using a digital camera to record images for 120 hours, with a standardized distance of 80cm between the lens and the specimen. Adobe Photoshop CS3 software was used for the measurement of the recorded images. The measurements refer to the equivalent distance between the two parallel lines printed on the samples. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test for multiple comparisons between the means of the groups. Results: There was no statistically significant difference (p > 0.05) when EPIHs were compared at the same time of evaluation. Orthoprint, Cavex Orthotrace, and Cavex Colorchange presented with least dimensional stability up to 24 hours (p > 0.05) of storage, followed by Jeltrate Plus (48 hours). Conclusions: Storage of EPIHs for more than 24 hours for Cavex ColorChange and 48 hours for others EPIHs studied produces significant dimensional changes in the impressions stored at a humidity of 70% (± 3) and temperature of 28°C (± 2). Extended storage times produce large dimensional changes.

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Extended-pour and conventional alginates: effect of storage time on dimensional accuracy and maintenance of details

Dental Press Journal of Orthodontics ◽

10.1590/2177-6709.26.3.e2119251.oar ◽

2021 ◽

Vol 26 (3) ◽

Author(s):

Sandro Basso BITENCOURT ◽

Isabela Araguê CATANOZE ◽

Emily Vivianne Freitas da SILVA ◽

Karina Helga Leal TURCIO ◽

Daniela Micheline dos SANTOS ◽

...

Keyword(s):

Dimensional Stability ◽

High Stability ◽

Digital Camera ◽

Dimensional Accuracy ◽

Dimensional Change ◽

Clinical Results ◽

Dimensional Changes ◽

Plastic Bags ◽

Significant Difference ◽

Student’S T

ABSTRACT Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student’s t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured.

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Dynamic moisture sorption and dimensional stability of furfurylated wood with low lignin content

Holzforschung ◽

10.1515/hf-2019-0033 ◽

2019 ◽

Vol 74 (1) ◽

pp. 68-76

Author(s):

Tiantian Yang ◽

Erni Ma ◽

Jinzhen Cao

Keyword(s):

Relative Humidity ◽

Dimensional Stability ◽

Furfuryl Alcohol ◽

Lignin Content ◽

Moisture Sorption ◽

Dimensional Change ◽

Poplar Wood ◽

Sorption Coefficient ◽

Dimensional Changes ◽

Sinusoidal Shape

AbstractDegradation of lignin occurs naturally in wood due to the influence of microorganisms or photic radiation. To improve the properties of wood with low lignin content, furfuryl alcohol (FA) at the concentration of 25% was used to modify poplar wood (Populus euramericana Cv.) after partial delignification. Moisture sorption and dimensional stability of the samples were investigated under dynamic conditions where the relative humidity (RH) was changed sinusoidally between 45% and 75% at 25°C. Both the moisture content (MC) and the tangential dimensional change varied with a sinusoidal shape similar to the RH. Hygroscopicity and hygroexpansion increased after delignification, while furfurylation led to an inverse impact by reducing MC, dimensional changes, amplitudes of MC and dimensional changes, moisture sorption coefficient (MSC), and humidity expansion coefficient (HEC). After delignification and further furfurylation, the MC and the dimensional changes were reduced by about 20%, and the maximum drop in amplitudes of MC and dimensional changes was about 30%, while the MSC and the HEC decreased by over 15%. In addition, the furfurylated wood with low lignin content exhibited lower sorption hysteresis and swelling hysteresis.

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The effects of mixing slurry water with type III gypsum on setting time, compressive strength and dimensional stability

Dental Journal (Majalah Kedokteran Gigi) ◽

10.20473/j.djmkg.v54.i4.p195-199 ◽

2021 ◽

Vol 54 (4) ◽

pp. 195

Author(s):

Chindy Fransiska Br Nainggolan ◽

Dwi Tjahyaning Putranti

Keyword(s):

Compressive Strength ◽

Dimensional Stability ◽

Setting Time ◽

Testing Machine ◽

Dimensional Change ◽

Calcium Sulphate ◽

Type Iii ◽

Significant Difference ◽

Change Of Type ◽

Group B

Background: Type III gypsum is a material used to make dental master casts. It may be added to an accelerator, such as slurry water, to shorten setting time. Calcium sulphate in slurry water may affect setting time, compressive strength and dimensional stability. Purpose: The study evaluated the effect of slurry water on the setting time, compressive strength and dimensional stability of type III gypsum. Methods: Eighty-one samples were made of type III gypsum, divided into three groups: group A was gypsum mixed with 1% slurry water, group B, gypsum mixed with 2% slurry water and group C, gypsum mixed with distilled water. Each sample was formed using a standardised master mould. For testing setting time, a cylindrical mould 25 mm in diameter and height was used; for compressive strength testing, the cylindrical mould was 20 mm in diameter and 40 mm in height; and for dimensional stability testing, a pair of cylindrical, ruled block and mould were used. Setting time was tested using Vicat’s apparatus; compressive strength was tested using a universal testing machine; and dimensional stability was tested using digital callipers. The data were analysed by one-way analysis of variance (ANOVA) and least significant difference (LSD) tests. Results: One-way ANOVA and LSD tests showed significant differences in the effect of slurry water on the setting time, compressive strength and dimensional stability of type III gypsum (p<0.05). Conclusion: The use of slurry water can shorten setting time, decrease compressive strength and increase dimensional change of type III gypsum.

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Linear dimensional stability of irreversible hydrocolloids with and without disinfection at different storage times

RSBO ◽

10.21726/rsbo.v15i2.673 ◽

2019 ◽

Vol 15 (2) ◽

pp. 77

Author(s):

Lidia Olga Bach Pinheiro ◽

Alfonso Sanchez Ayala ◽

Marcos Cezar Pomini ◽

Vanessa Taborda da Cruz ◽

Ingrid Viel del Farias ◽

...

Keyword(s):

Stainless Steel ◽

Dimensional Stability ◽

Storage Time ◽

Dental Practice ◽

Type Iv ◽

Significant Difference ◽

Irreversible Hydrocolloid ◽

Master Model ◽

Storage Times ◽

Digital Caliper

Irreversible hydrocolloids have been used in dental practice for decades and their pouring time has been suggested to be as short as possible; however the latest generation of alginates exhibit better properties, which could influence the fidelity of the casts. Objective: To evaluate the linear dimensional stability of stone casts obtained using two irreversible hydrocolloid brands (Cavex ColorChange and Jeltrate) after disinfection. Material and methods: Samples were divided into 16 groups (n = 10) according to brand, storage time and disinfection. Impressions were taken of a metallic master model made of stainless steel with two abutments. Cast models were obtained using type IV gypsum, after disinfection with sodium hypochlorite at 1% or without any disinfection followed by storage for four different times (immediate pouring, and after 24, 72 or 120 hours storage after obtaining the impressions) and the models were measured with a digital caliper. Data were submitted to ANOVA 3-way followed by Tukey’s test (α < 0.05). Results: A statistically significant difference was detected with Jeltrate Plus after 72 and 120 hours in storage (with and without disinfection), as well as Cavex without disinfection. Differences were found for Cavex with disinfection/24 hours storage, when compared to immediate pouring (P < 0.05). The alginates presented similar behavior regarding disinfection for the same time (P > 0.05). Conclusion: Storage longer than 24 hours affects the fidelity of casts. Disinfection does not promote significant alteration at any of the experimental times with either material.

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Dimensional changes of alginate impression by using perforated and non-perforated ring trays

Padjadjaran Journal of Dentistry ◽

10.24198/pjd.vol22no1.14071 ◽

2010 ◽

Vol 22 (1) ◽

Author(s):

Sumadhi Sastrodihardjo

Keyword(s):

Dimensional Change ◽

Base Diameter ◽

Impression Material ◽

Dimensional Changes ◽

Base Area ◽

Change Mechanism ◽

Impression Materials ◽

Significant Difference ◽

Materials Used

Dimensional changes are a common occurrence in impressions, either during or after impression taking. It produces a difference in the dimensions of the object and the model, which leads to the restoration being ill-fitted. Several causal factors have been proposed such as friction between the impression material and the teeth, the bulk of the impression material, the type of impression materials used, the impression technique, the pouring time and many others. The exact causal factor is still unknown and the dimensional change mechanism is still poorly understood. The objective of this research was to investigate the role of the perforation on the ring trays in producing dimensional changes in the impression by using perforated and non-perforated ring trays. Alginate impressions were made on the frustum of cone metal master die with a 7.08 mm base diameter, 7.03 mm top diameter and 9.23 mm height using perforated and non-perforated ring trays with 9.40 mm in diameter and 14.17 mm in height. The dimensional change was determined by comparing the dimension of the dental stone die and its metal master die. The results showed that the percentage of dimensional changes that occurred by using perforated ring tray were (+) 0.56±0.40 on the top area, (-) 3.54±2.92 on base area and (+) 1.54±0.83 in height, respectively. As compared to using non-perforated ring trays, the percentage of dimensional changes that occurred were (-) 0.49±0.49 on top area, (-) 8.76±3.95 on base area and (+) 1.19±0.71 in height, respectively. There was a significant difference in the direction of the dimensional changes on both the top areas, but not in the base areas and height.

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Linear dimensional stability of irreversible hydrocolloids with and without disinfection at different storage times

RSBO ◽

10.21726/rsbo.v15i2.617 ◽

2018 ◽

Vol 15 (2) ◽

pp. 77-83

Author(s):

Lidia Olga Bach Pinheiro ◽

Alfonso Sanchez Ayala ◽

Marcos Cezar Pomini ◽

Vanessa Taborda da Cruz ◽

Ingrid Viel del Farias ◽

...

Keyword(s):

Stainless Steel ◽

Dimensional Stability ◽

Storage Time ◽

Dental Practice ◽

Type Iv ◽

Significant Difference ◽

Irreversible Hydrocolloid ◽

Master Model ◽

Storage Times ◽

Digital Caliper

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Comparison of disinfectants by immersion and spray atomization techniques on the linear dimensional stability of different interocclusal recording materials: An in vitro study

European Journal of Dentistry ◽

10.4103/1305-7456.175684 ◽

2016 ◽

Vol 10 (01) ◽

pp. 007-015 ◽

Cited By ~ 3

Author(s):

Revathy Gounder ◽

B. V. J. Vikas

Keyword(s):

Sodium Hypochlorite ◽

Dimensional Stability ◽

Dimensional Change ◽

Chlorhexidine Gluconate ◽

Spray Atomization ◽

Time Duration ◽

Significance Level ◽

Significant Difference ◽

Immersion Technique

ABSTRACT Objective: To evaluate and compare the effect of 0.5% chlorhexidine gluconate, 1% sodium hypochlorite, and 2% glutaraldehyde by immersion and spray atomization technique on the linear dimensional stability of Jet bite, Aluwax and Ramitec interocclusal recording materials. Materials and Methods: Three representative materials: Jet bite (addition silicone), Aluwax and Ramitec (polyether) were mixed according to manufacturer's instructions and then specimens were prepared according to the specifications of ISO 4823. All the specimens except the control (distilled water) were treated with disinfectant solutions (0.5% chlorhexidine gluconate, 1% sodium hypochlorite, and 2% glutaraldehyde) for 30 and 60 min (n = 10) by spray and immersion technique. Once removed from the solutions, the test samples were washed in water for 15 s, dried and measured after 24 h 3 times using a measuring microscope with an accuracy of 0.0001 mm. Two-way ANOVA and Tukey's test with significance level of 5% were used to assess the statistical data (α = 0.05). Result: All groups showed no significant difference statistically, in linear dimension when disinfected for 30 min by spray or immersion technique. Polyether had significantly higher dimensional variation when immersed in sodium hypochlorite for 60 min. Addition silicone showed the least dimensional change which ranged from 0.024% to 0.05%, followed by polyether from 0.004% to 0.171% and Aluwax from 0.146% to 0.228%. Conclusion: To preserve the dimensions and surface of the recording materials and effective microbial elimination, restrictions should be applied in the method of disinfection and time duration. However, using the disinfectants either by spray or immersion technique, the dimensional change was <0.5% which was not clinically significant according to the American Dental Association specification no. 19 criteria within the first 24 h.

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The accuracy of gypsum casts obtained from the disinfected extended-pour alginate impressions through prolonged storage times

BMC Oral Health ◽

10.1186/s12903-021-01649-2 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Rania A. Sharif ◽

Khalid M. Abdelaziz ◽

Najla M. Alshahrani ◽

Fatimah S. Almutairi ◽

Mohrah A. Alaseri ◽

...

Keyword(s):

Dimensional Stability ◽

Storage Time ◽

Prolonged Storage ◽

Time Intervals ◽

Superior Surface ◽

Stability Data ◽

Surface Detail ◽

Storage Times ◽

One Way Anova ◽

Chemical Disinfection

Abstract Background Manufacturers of the extended-pour alginates claimed their dimensional stability through prolonged storage. No data confirmed the ability of these materials to maintain their dimensions and the reproduced oral details following their chemical disinfection. Therefore, this study evaluated the dimensional stability and surface detail reproduction of gypsum casts obtained from disinfected extended-pour alginate impressions through different storage time intervals. Methods Two hundred and forty three hydrocolloid impressions were made from one conventional (Tropicalgin) and two extended-pour (Hydrogum 5 and Chromaprint premium) alginates. These impressions were subjected to none, spray and immersion disinfection before their storage in 100% humidity for 0, 72 and 120 h. The dimensional stability and the surface detail reproduction were indirectly evaluated under low angle illumination on the resulted gypsum casts. At α = 0.05, the parametric dimensional stability data were analyzed using One-Way ANOVA and Tukey’s comparisons, while the nonparametric detail reproduction data were analyzed using KrusKal Wallis and Mann–Whitney's tests. Results All gypsum casts exhibited a degree of expansion; however, the recorded expansion values did not differ between test categories (P > 0.05). Generally, casts obtained from spray-disinfected impressions showed lower detail accuracy (P < 0.05). Immersion-disinfected extended-pour alginates produced casts with better detail accuracy following 120 h of storage (P < 0.05). Conclusion All alginates materials offer comparable cast dimensions under different testing circumstances. Extended-pour alginates offer casts with superior surface details following their immersion disinfection and 120 h of storage. Spray-disinfection using 5.25% sodium hypochlorite affects the surface details of casts obtained from conventional and extended-pour alginates adversely.

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A Simple Numerical Method for Determining the Sensitivity of Bending Deflections of Stepped Shafts to Dimensional Changes

Journal of Vibration and Acoustics ◽

10.1115/1.3274706 ◽

1985 ◽

Vol 107 (1) ◽

pp. 141-146

Author(s):

G. Umasankar ◽

C. R. Mischke

Keyword(s):

Dimensional Change ◽

Element Model ◽

Neutral Axis ◽

Computationally Efficient ◽

Simple Method ◽

Dimensional Changes ◽

Stepped Shaft ◽

Dimension Change ◽

Deflection Analysis ◽

Uniform Diameter

A simple method of computing the effect of a dimensional change at a particular element of a stepped shaft on two bearings, on bending deflections, and on slopes of the neutral axis at any of the nodes of interest is presented. The changes in deflection and slope of the neutral axis are derived as incremental quantities and as functions of the dimension change and the prior deflections and slopes of the neutral axis of the shaft. For shaft synthesis, the implications are that one can begin with a uniform diameter bar subjected to the loading and make a complete deflection analysis with superposed closed-form relations. Then the geometry can be modified element by element and the deflectional changes easily updated. This is computationally efficient. Further, deflections and deflection changes computed using the proposed method are identical to those obtained using a finite beam element model of the shaft.

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Elastomeric Impression Materials: A Comparison of Accuracy of Multiple Pours

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-1046 ◽

2011 ◽

Vol 12 (4) ◽

pp. 272-278 ◽

Cited By ~ 3

Author(s):

Dheeraj Kumar ◽

Anand U Madihalli ◽

K Rajeev Kumar Reddy ◽

Namrataa Rastogi ◽

NT Pradeep

Keyword(s):

Clinical Significance ◽

Dimensional Stability ◽

Central Hole ◽

Central Incisor ◽

Impression Material ◽

Maxillary Central Incisor ◽

Dimensional Changes ◽

The Third ◽

Impression Materials ◽

Time Periods

ABSTRACT Aim The aim of the present study is to compare the various elastomeric impression materials in terms of accuracy and dimensional stability, with respect to obtaining multiple casts from a single elastomeric impression at various times of pours. Materials and methods Three master dies were prepared for the impression making, two of these were made of brass containing a central hole with undercuts. The third die simulated a conventionally prepared typodont maxillary central incisor. Three elastomeric impression materials were chosen for the study. Each impression was poured at various time periods. Casts thus obtained were evaluated under a traveling microscope to evaluate various dimensional changes. Results Addition silicones provided dies which were shorter in height and bigger in diameter. Polyethers provided dies which were shorter in both height and diameter. Condensation silicones showed insignificant changes from the master die at the immediate pour but deteriorated rapidly after that in subsequent pours. Conclusion None of the impression material showed a consistent behavior up to the fourth pour. They occasionally showed deviation from the pattern, but all these values were statistically insignificant. Polyethers showed lesser ability than both the addition silicones as well as the condensation silicones to recover from induced deformation. Clinical significance Addition silicones as well as the condensation silicones have better ability to recover from induced deformation when compared to polyether. How to cite this article Kumar D, Madihalli AU, Reddy KRK, Rastogi N, Pradeep NT. Elastomeric Impression Materials: A Comparison of Accuracy of Multiple Pours. J Contemp Dent Pract 2011;12(4):272-278.

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