Accuracy of stone casts obtained by different impression materials

Faria, Adriana Cláudia Lapria; Rodrigues, Rossana Lott; Macedo, Ana Paula; Mattos, Maria da Glória Chiarello de; Ribeiro, Ricardo Faria

doi:10.1590/s1806-83242008000400002

Cited by 89 publications

(83 citation statements)

References 14 publications

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“…Studies have also shown inconsistent results for irreversible hydrocolloid impressions. 46,47 Another patient-specific factor sometimes discussed is the deformation of the mandible during jaw opening. In this in vivo study, no difference was visible between the precision of maxillary and mandibular impressions in both the conventional and digital impression groups.…”

Section: Discussionmentioning

confidence: 99%

In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions

Ender

Attin

Mehl

2016

The Journal of Prosthetic Dentistry

426

437

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STATEMENT OF PROBLEM: Digital impression systems have undergone significant development in recent years, but few studies have investigated the accuracy of the technique in vivo, particularly compared with conventional impression techniques. PURPOSE: The purpose of this in vivo study was to investigate the precision of conventional and digital methods for complete-arch impressions. MA-TERIAL AND METHODS: Complete-arch impressions were obtained using 5 conventional (polyether, POE; vinylsiloxanether, VSE; direct scannable vinylsiloxanether, VSES; digitized scannable vinylsiloxanether, VSES-D; and irreversible hydrocolloid, ALG) and 7 digital (CEREC Bluecam, CER; CEREC Omnicam, OC; Cadent iTero, ITE; Lava COS, LAV; Lava True Definition Scanner, T-Def; 3Shape Trios, TRI; and 3Shape Trios Color, TRC) techniques. Impressions were made 3 times each in 5 participants (n=15). The impressions were then compared within and between the test groups. The cast surfaces were measured point-to-point using the signed nearest neighbor method. Precision was calculated from the (90%-10%)/2 percentile value. RESULTS: The precision ranged from 12.3 m (VSE) to 167.2 m (ALG), with the highest precision in the VSE and VSES groups. The deviation pattern varied distinctly according to the impression method. Conventional impressions showed the highest accuracy across the complete dental arch in all groups, except for the ALG group. CONCLUSIONS: Conventional and digital impression methods differ significantly in the complete-arch accuracy. Digital impression systems had higher local deviations within the complete arch cast; however, they achieve equal and higher precision than some conventional impression materials. techniques. Impressions were made 3 times each in 5 participants (n = 15). The impressions were then compared within and between the test groups. The cast surfaces were measured point-to-point using the signed nearest neighbor method. Precision was calculated from the (90%-10%)/2 percentile value.Results. The precision ranged from 12.3 µm (VSE) to 167.2 µm (ALG), with the highest precision in the VSE and VSES groups. The deviation pattern varied distinctly according to the impression method. Conventional impressions showed the highest accuracy across the complete dental arch in all groups, except for the ALG group.Conclusions. Conventional and digital impression methods differ significantly in the complete-arch accuracy. Digital impression systems had higher local deviations within the 2 complete arch cast; however, they achieve equal and higher precision than some conventional impression materials. CLINICAL IMPLICATIONSThe accuracy of complete-arch impression casts differs significantly between conventional techniques and digital impression systems. Local deviations are greater in casts generated using digital impression systems; however, digital systems show adequate accuracy across the complete arch. As digital impression systems continue to improve, they may prove to be an equivalent or better alternative to convent...

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Section: Discussionmentioning

confidence: 99%

In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions

Ender

Attin

Mehl

2016

The Journal of Prosthetic Dentistry

426

437

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“…The results of the present study confirm the excellent dimensional stability and the reproduction of details achieved when using this material, as described previously. [11][12][13] The condensation silicone shows low resistance to rip and higher deformation than other elastomeric materials, and increased distortion when it is stored prior to pouring. The dimensional instability may be due to ethylic alcohol, which could be produced as a by-product of the chemical reaction of this silicone.…”

Section: Discussionmentioning

confidence: 99%

“…Addition silicones, mercaptanpolysulfides, and polyetheres are the most common additives for this procedure. [8][9][10][11][12][13][14][15][16][17] The thickness of the impression material, in addition to the effects of temperature and the materials used, influences the mould, producing excessive distortion of the impression. 9,10 The individual shell technique is advantageous because the thickness of the material is less and it thus produces only minor dimensional changes in the impression.…”

Section: Introductionmentioning

confidence: 99%

Linear dimensional changes in plaster die models using different elastomeric materials

et al. 2010

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Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F) were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05) and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD = 15.0 µm, EF = 14.6 µm, GH = 15.2 µm), mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm), polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm) and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm). All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.

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“…3 Alginate and gypsum are materials extensively used to make impressions and casts, respectively. 4,5 The alginate presents problems with dimensional stability over time, and water loss causes roughness on the plaster surface, therefore it is not recommended for the construction of indirect restorations. 4 However, it has been the material of choice for making orthodontic study models, Declaration.of.Interests:.The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.…”

Section: Introductionmentioning

confidence: 99%

“…because it is easy to use, is well accepted by the patient, has low cost, 4,6,7 and presents adequate dimensional stability, provided that the manufacturer's instructions as regards pouring time are followed.…”

Section: Introductionmentioning

confidence: 99%

Does the contact time of alginate with plaster cast influence its properties?

et al. 2012

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The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1) -with time of contact of 1 hour; and Group 2 (G2) -12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan), respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA) under a load of 100 gF for 15 s. The results showed significant difference (P ≤ 0.05) between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.

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Accuracy of stone casts obtained by different impression materials

Cited by 89 publications

References 14 publications

In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions

In vivo precision of conventional and digital methods of obtaining complete-arch dental impressions

Linear dimensional changes in plaster die models using different elastomeric materials

Does the contact time of alginate with plaster cast influence its properties?

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