A comparative study of marginal fit of copings prepared with various techniques on different implant abutments

Abstract

This study evaluated fabrication techniques of recently introduced all-ceramic copings' marginal adaptation on two different implant abutments with different finish lines. Five different copings were prepared (Casted chrome-cobalt metal coping, Zirkonzahn, Cercon, In Ceram Alumina and IPS e.max Press) on two cementable implant abutments with two marginal designs. Ten samples for each coping group were prepared (totally 100 samples). Copings were cemented to implant abutments and marginal gap measurements were done from 24 points with stereomicroscope and the datas were analyzed by the Kruskal-Wallis test before cementation. Cercon copings showed the lowest marginal fit scores and metal copings showed the highest scores. After cementation, all marginal gap values have been increased. All marginal gap values obtained from crown copings can be considered in clinically acceptable limits (<120 µm) except metal copings after cementation on abutment with 135 degrees shoulder group (123 µm).

Evaluation of Marginal Fits of Crown Substructure Designs in Implant-Supported Abutments

“…Several studies have reported that marginal discrepancy values greater than 120 μm are clinically unacceptable [9–11,17,18]. In the present study, no specimen showed a mean marginal discrepancy value greater than 120 μm; therefore, all methods were found to be successful in terms of marginal fit [21,22]. The direct microscopy method is the most straightforward, least time consuming, most easily repeated, and least expensive of the 4 methods, but the precision of measurements is lower, and selection of measurement points is more challenging.…”

Adaptability Evaluation of Metal-Ceramic Crowns Obtained by Additive and Subtractive Technologies

“…These images are superimposed and analyzed with specific software. This is a good alternative for traditional silicon replica but is more expensive because it requires an intra-oral scanner for clinical use [18,19]. The best evaluating method for crown adaptation is the invasive method, well known but with some critical issues which limit its applicability.…”

SEM evaluation of the precision of fit of CAD/CAM zirconia and metal-ceramic posterior crowns

“…Some methods include perfilometry 14) and microfiltration with dyes, whose main drawback is the subjectivity inherent in using semi-quantitative measuring scales 17,18,30) . Direct viewing with external measurements has the advantage of being noninvasive and is, therefore, useful to determine the precision of fit of the restorations 7,15,29) . Several studies investigating the internal marginal fit are based on measurements of sectioned teeth, and although extremely accurate, these measurements result in the destruction of the restoration and consequently are of little use in clinical practice 15,20) .…”

“…Another limitation of the study was that a different dental laboratory technician fabricated each group of crowns, however, in the present study, the internal surface of zirconia copings was not adjusted by the technician, avoiding that the proficiency of the technician could influence the results 17) , although this does not reflect the clinical situation. The study includes measuring only the vertical marginal fit and this might no represent the precision of fit of the whole specimen 23,29) . Despite the variety of methodologies available, certain aspects have yet to be clarified and more studies are needed to compare the reliability of the instruments and the techniques used to measure the marginal fit in ceramic crowns and to conclusively determine the ideal technique for measuring marginal gap.…”

“…In the present study, marginal adaptation was evaluated by direct viewing with external and internal measurements and although various protocols have been proposed to analyze the marginal gap, no general guideline exists on how to perform gap measurements 9,15,[27][28][29] . Several direct and indirect methods are available for analyzing the marginal and internal adaptation of fixed prosthodontics restorations.…”