scholarly journals Assessment of Fit on Ten Screw-Retained FrameworksRealized through Digital Full-Arch Implant Impression

2021 ◽  
Vol 11 (12) ◽  
pp. 5617
Author(s):  
Maurizio De Francesco ◽  
Edoardo Stellini ◽  
Stefano Granata ◽  
Sergio Mazzoleni ◽  
Francesco Saverio Ludovichetti ◽  
...  
Keyword(s):  
Surgical Procedure ◽  
Test Methods ◽  
Digital Impression ◽  
Rank Test ◽  
Microscope Examination ◽  
Dental Prostheses ◽  
Digital Impressions ◽  
Fixed Dental Prostheses ◽  
The Mean ◽  
Master Model

Background: Discordant opinions have emerged among clinicians and researchers regarding a digital impression for full-arch implant-supported fixed dental prostheses (FDPs). The purpose of this study was to assess the fit of screw-retained milled frameworks on six implants realized from digital impressions through the Sheffield test. Methods: One patient received a maxillary full-arch implant-supported FDP. Six months after the surgical procedure, ten intraoral full-arch digital impressions were performed to mill ten frameworks. To clinically assess the fit, the Sheffield test was applied for all frameworks. The gaps among the frameworks and the implant analogs were measured using a microscope on the master model realized with a traditional impression. The Wilcoxon sum-rank test was used to compare the misfit value among the different implant positions. Results: The Sheffield test did not show gaps in the framework–implant interfaces when the screw was completely tightened on the more distal implant for all the milled frameworks. The mean misfit value calculated after microscope examination was 38 ± 5 μm. Differences that were statistically significant emerged when the misfit values of central positions were compared with other values. Conclusions: The use of full-arch implant digital impressions represents a viable alternative to traditional impressions for the fabrication of implant-supported FDPs.

scholarly journals Marginal and Internal Fit of Cobalt-Chromium Fixed Dental Prostheses Generated from Digital and Conventional Impressions

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Per Svanborg ◽  
Henrik Skjerven ◽  
Pablo Carlsson ◽  
Alf Eliasson ◽  
Stig Karlsson ◽  
...  
Keyword(s):  
Digital Impression ◽  
Cobalt Chromium ◽  
Marginal Gap ◽  
Impression Material ◽  
Dental Prostheses ◽  
Digital Impressions ◽  
Fixed Dental Prostheses ◽  
Internal Fit ◽  
Cervical Area ◽  
Scan Protocol

Objectives. Digital impressions are increasingly used and have the potential to avoid the problem of inaccurate impressions. Only a few studies to verify the accuracy of digital impressions have been performed. The purpose of this study was to compare the marginal and internal fit of 3-unit tooth supported fixed dental prostheses (FDPs) fabricated from digital and conventional impressions.Methods. Ten FDPs were produced from digital impressions using the iTero system and 10 FDPs were produced using vinyl polysiloxane (VPS) impression material. A triple-scan protocol and CAD software were used for measuring and calculating discrepancies of the FDPs at 3 standard areas: mean internal discrepancy, absolute marginal gap, and cervical area discrepancy. The Mann-Whitney U test was used for analyzing the results.Results. For conventional and digital impressions, respectively, FDPs had an absolute marginal gap of 147 μm and 142 μm, cervical area discrepancy of 69 μm and 44 μm, and mean internal discrepancy of 117 μm and 93 μm. The differences were statistically significant in the cervical and internal areas (P<0.001).Significance. The results indicated that the digital impression technique is more exact and can generate 3-unit FDPs with a significantly closer fit compared to the VPS technique.

scholarly journals Accuracy of Master Casts Generated Using Conventional and Digital Impression Modalities: Part 1—The Half-Arch Dimension

2021 ◽  
Vol 11 (24) ◽  
pp. 12034
Author(s):  
Mohammed E. Sayed ◽  
Abdulkarim Hussain Alshehri ◽  
Bandar M. A. Al-Makramani ◽  
Fuad Al-Sanabani ◽  
Fawzia Ibraheem Shaabi ◽  
...  
Keyword(s):  
Digital Impression ◽  
Digital Models ◽  
Four Dimensions ◽  
Dental Prostheses ◽  
Impression Materials ◽  
Digital Impressions ◽  
Significant Difference ◽  
Alternative Materials ◽  
Fixed Dental Prostheses ◽  
Conventional Impression

Accurate impression-making is considered a vital step in the fabrication of fixed dental prostheses. There is a paucity of studies that compare the casts generated by various impression materials and techniques that are commonly used for the fabrication of provisional and definitive fixed prostheses. The aim of this study is to compare the accuracy of casts obtained using conventional impression and digital impression techniques. Thirty impressions were made for the typodont model (10 impressions each of polyvinyl siloxane, alginate, and alginate alternative materials). Ten digital models were printed from the same model using a TRIOS-3 3Shape intraoral scanner. Accuracy was assessed by measuring four dimensions (horizontal anteroposterior straight, horizontal anteroposterior curved, horizontal cross-arch, and vertical). A one-way ANOVA and Tukey’s test (α = 0.05) were used to analyze data. A statistically significant difference in the four dimensions of the stone casts and digital models was observed among the four groups (exception: between alginate alternative and 2-step putty–light body impression in the horizontal anteroposterior straight, horizontal anteroposterior curved, and horizontal cross-arch dimensions; between alginate and alginate alternative in the horizontal anteroposterior curved dimension; between alginate and 2-step putty–light body impression in the horizontal anteroposterior curved dimension; and between alginate alternative and digital in the vertical dimension). Polyvinyl siloxane had the highest accuracy compared to casts obtained from other impression materials and digital impressions.

scholarly journals A New Method to Evaluate Trueness and Precision of Digital and Conventional Impression Techniques for Complete Dental Arch

2021 ◽  
Vol 11 (10) ◽  
pp. 4612
Author(s):  
KweonSoo Seo ◽  
Sunjai Kim
Keyword(s):  
Intraclass Correlation ◽  
Three Dimensional ◽  
New Method ◽  
Digital Impression ◽  
Dental Arch ◽  
Digital Models ◽  
Digital Impressions ◽  
Measuring Machine ◽  
Master Model ◽  
Conventional Impression

Purpose: The aim of this study was to present a new method to analyze the three-dimensional accuracy of complete-arch dental impressions and verify the reliability of the method. Additionally, the accuracies of conventional and intraoral digital impressions were compared using the new method. Methods: A master model was fabricated using 14 milled polyetheretherketone cylinders and a maxillary acrylic model. Each cylinder was positioned and named according to its corresponding tooth position. Twenty-five definitive stone casts were fabricated using conventional impressions of the master model. An intraoral scanner was used to scan the master model 25 times to fabricate 25 digital models. A coordinate measuring machine was used to physically probe each cylinder in the master model and definitive casts. An inspection software was used to probe cylinders of digital models. A three-dimensional part coordinate system was defined and used to compute the centroid coordinate of each cylinder. Intraclass correlation coefficient (ICC) was evaluated to examine the reliability of the new method. Independent two sample t-test was performed to compare the trueness and precision of conventional and intraoral digital impressions (α = 0.05). Results: ICC results showed that, the new method had almost perfect reliability for the measurements of the master model, conventional and digital impression. Conventional impression showed more accurate absolute trueness and precision than intraoral digital impression for most of the tooth positions (p < 0.05). Conclusions: The new method was reliable to analyze the three-dimensional deviation of complete-arch impressions. Conventional impression was still more accurate than digital intraoral impression for complete arches.

scholarly journals An Evaluation of the Gap Sizes of 3-Unit Fixed Dental Prostheses Milled from Sintering Metal Blocks

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Jae-Kwan Jung
Keyword(s):  
Standard Deviation ◽  
Gap Size ◽  
Sintered Metal ◽  
Dental Prostheses ◽  
Fixed Dental Prostheses ◽  
The Mean ◽  
Metal Block

This study assessed the clinical acceptability of sintering metal-fabricated 3-unit fixed dental prostheses (FDPs) based on gap sizes. Ten specimens were prepared on research models by milling sintering metal blocks or by the lost-wax technique (LWC group). Gap sizes were assessed at 12 points per abutment (premolar and molar), 24 points per specimen (480 points in a total in 20 specimens). The measured points were categorized as marginal, axial wall, and occlusal for assessment in a silicone replica. The silicone replica was cut through the mesiodistal and buccolingual center. The four sections were magnified at 160x, and the thickness of the light body silicone was measured to determine the gap size, and gap size means were compared. For the premolar part, the mean (standard deviation) gap size was nonsignificantly (p=0.139) smaller in the SMB group (68.6 ± 35.6 μm) than in the LWC group (69.6 ± 16.9 μm). The mean molar gap was nonsignificantly smaller (p=0.852) in the LWC (73.9 ± 25.6 μm) than in the SMB (78.1 ± 37.4 μm) group. The gap sizes were similar between the two groups. Because the gap sizes were within the previously proposed clinically accepted limit, FDPs prepared by sintered metal block milling are clinically acceptable.

scholarly journals Use of digital impression systems with intraoral scanners for fabricating restorations and fixed dental prostheses

2018 ◽  
Vol 60 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Yoshimasa Takeuchi ◽  
Hiroyasu Koizumi ◽  
Mika Furuchi ◽  
Yohei Sato ◽  
Chikahiro Ohkubo ◽  
...  
Keyword(s):  
Digital Impression ◽  
Dental Prostheses ◽  
Fixed Dental Prostheses

scholarly journals A Study to Evaluate Life Span of Crowns & Fixed Partial Dentures and Various Reasons of their Failures

2013 ◽  
Vol 01 (02) ◽  
pp. 095-099
Author(s):  
Gursharan Singh ◽  
Nishtha Madan ◽  
Mandeep Kumar ◽  
Cherry Walia ◽  
Opinder Singh
Keyword(s):  
Periodontal Disease ◽  
Life Span ◽  
Initial Treatment ◽  
Survival Period ◽  
Periapical Lesion ◽  
Oral Diseases ◽  
Length Of Service ◽  
Dental Prostheses ◽  
Fixed Dental Prostheses ◽  
The Mean

AbstractMost patients are concerned about the anticipated length of service and reasons of replacement of fixed dental prostheses (FPDs). This study tried to find out relationship among various factors causing failures in fixed dental prostheses. Patients treated with fixed dental prostheses were examined clinically and radiographically. A group of 106 patients were evaluated for unsatisfactory restorations. These groups of patients produced records of initial treatment to ascertain the length of service of restoration. The mean survival period of fixed dental prostheses was 7.5 years. This investigation helped find causes for failures and survival period of various FPDs. Among the reasons of failures, caries was the most frequently observed (24.2%), followed by defective margin (18.2%), unsatisfactory esthetics (15.2%), retention problem (11.7%), periodontal disease (8.8%), fractured tooth (10.6%), periapical lesion (5.8%), porcelain fracture (4.2%) and others (1.3%). Causes of failures were also grouped into two groups (Mechanical & Oral diseases) for comparison. The Mechanical group showed higher failure percentage (59.9%) as compared to Oral diseases group (38.8%).

Correlation of AGR2 expression with the incidence of metastasis in luminal breast cancer

2021 ◽  
pp. 1-5
Author(s):  
David Samuel Kereh ◽  
John Pieter ◽  
William Hamdani ◽  
Haryasena Haryasena ◽  
Daniel Sampepajung ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Mean Value ◽  
Rank Test ◽  
Luminal Breast Cancer ◽  
P Value ◽  
Strong Positive Correlation ◽  
Breast Cancer Patients ◽  
The Mean ◽  
Spearman Test

BACKGROUND: AGR2 expression is associated with luminal breast cancer. Overexpression of AGR2 is a predictor of poor prognosis. Several studies have found correlations between AGR2 in disseminated tumor cells (DTCs) in breast cancer patients. OBJECTIVE: This study aims to determine the correlation between anterior Gradient2 (AGR2) expression with the incidence of distant metastases in luminal breast cancer. METHODS: This study was an observational study using a cross-sectional method and was conducted at Wahidin Sudirohusodo Hospital and the network. ELISA methods examine AGR2 expression from blood serum of breast cancer patients. To compare the AGR2 expression in metastatic patients and the non-metastatic patient was tested with Mann Whitney test. The correlation of AGR2 expression and metastasis was tested with the Rank Spearman test. RESULTS: The mean value of AGR2 antibody expression on ELISA in this study was 2.90 ± 1.82 ng/dl, and its cut-off point was 2.1 ng/dl. Based on this cut-off point value, 14 subjects (66.7%) had overexpression of AGR2 serum ELISA, and 7 subjects (33.3%) had not. The mean value AGR2 was significantly higher in metastatic than not metastatic, 3.77 versus 1.76 (p < 0.01). The Spearman rank test obtained a p-value for the 2 tail test of 0.003 (p < 0.05), which showed a significant correlation of both, while the correlation coefficient of 0.612 showed a strong positive correlation of AGR2 overexpression and metastasis. CONCLUSIONS: AGR2 expression is correlated with metastasis in Luminal breast cancer.

scholarly journals Inlay-Retained Dental Bridges—A Finite Element Analysis

2021 ◽  
Vol 11 (9) ◽  
pp. 3770
Author(s):  
Monica Tatarciuc ◽  
George Alexandru Maftei ◽  
Anca Vitalariu ◽  
Ionut Luchian ◽  
Ioana Martu ◽  
...  
Keyword(s):  
Finite Element ◽  
Young Patients ◽  
Maximum Pressure ◽  
Class Iii ◽  
Element Analysis ◽  
Dental Prostheses ◽  
Abutment Teeth ◽  
Fixed Dental Prostheses ◽  
Implant Therapy ◽  
The Stability

Inlay-retained dental bridges can be a viable minimally invasive alternative when patients reject the idea of implant therapy or conventional retained full-coverage fixed dental prostheses, which require more tooth preparation. Inlay-retained dental bridges are indicated in patients with good oral hygiene, low susceptibility to caries, and a minimum coronal tooth height of 5 mm. The present study aims to evaluate, through the finite element method (FEM), the stability of these types of dental bridges and the stresses on the supporting teeth, under the action of masticatory forces. The analysis revealed the distribution of the load on the bridge elements and on the retainers, highlighting the areas of maximum pressure. The results of our study demonstrate that the stress determined by the loading force cannot cause damage to the prosthetic device or to abutment teeth. Thus, it can be considered an optimal economical solution for treating class III Kennedy edentation in young patients or as a provisional pre-implant rehabilitation option. However, special attention must be paid to its design, especially in the connection area between the bridge elements, because the connectors and the retainers represent the weakest parts.

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