Assessment of internal fit and micro leakage of conventionally fabricated ceramometallic restoration versus CAD wax and press veneering (in-vitro study)

Abstract

Statement of problem Accuracy of internal fit and microleakage for CAD-CAM systems used in metal coping fabrication and veneered with layering or pressing porcelain in ceramometallic restoration is unclear. Material and methods A master metal die was milled to resemble the right mandibular first molar preparation for coverage with ceramometallic restoration. Master die was duplicated to twenty-four resin specimen dies.They were divided into two groups according to metal coping construction technique using either conventional (C) or CAD (D) wax. Each group was subdivided into two subgroups (n = 6) according to the technique of porcelain veneering (layered or pressed) to fabricate ceramometallic restorations, where subgroup (CL, DL) were conventionally layered by porcelain and (CP, DP) were press veneered. A standardized thickness of metal and porcelain was performed in all specimens as per manufacturer’s instructions for techniques ceramometallic restoration construction. Evaluation of internal fit was done with silicone replica technique using stereomicroscope at ×24 magnification where the thickness of silicon layer was measured at 20 reference points on each specimen. Then specimens were subjected to thermocycling. Sectioned specimens were assessed for microleakage using a stereomicroscope at ×12 magnification along die-cement interface with a five scale score. Results Mean internal gap values of veneering showed a statistically nonsignificant difference between specimens made with layering(L) and pressing(P). Different techniques of wax construction showed a non-significant difference in internal gap values between specimens made with conventional(C) and CAD(D) waxing. However, a significant difference was found in the internal gap at different sites. The highest internal gap was found at the occlusal surface, while the lowest gap was found at the finish line. The highest mean microleakage score was found with CAD wax and press veneering, while the lowest mean microleakage score was found with conventional wax and press veneering. Conclusion Both construction techniques of ceramometallic restoration were considered reliable in restoration production within a clinically acceptable range regarding internal fit and microleakage. There is a strong positive correlation between internal fit and microleakage of ceramometallic restoration constructed.

Comparison of Marginal Integrity and Surface Roughness of Selective Laser Melting, CAD-CAM and Digital Light Processing Manufactured Co-Cr Alloy Copings

“…CAD-CAM offers standard-quality restorations, time efficiency, dimensional accuracy, and reduced risk of health hazards [12,13]. However, subtractive technique is associated with material wastage along with increased cost and difficult accessibility [14]. Current literature demonstrates conflicting outcomes related to the effect of Ra on the marginal misfit of metal copings fabricated using the subtractive technique [15,16].…”

Marginal Misfit of 3D-Printed (Selective Laser Sintered), CAD-CAM and Lost Wax Technique Cobalt Chromium Copings with Shoulder and Chamfer Finish Lines: An In-Vitro Study

“…In addition, the presence of a cement layer requires maintaining a standard load during coping seating to avoid errors in in-vitro studies [ 6 ]. Interestingly, ceramic firing on metal copings may compromise the marginal fit of metal-ceramic crowns; however, it was not performed in the present study, to avoid introducing inaccuracies in evaluating the effect of technique and finish lines on misfit [ 5 ]. However, further studies investigating the influence of ceramic firing on the marginal misfit of SLM fabricated metal alloy copings are recommended.…”

“…SLM copings showed comparable misfit outcomes to CAD-CAM and LWT methods for all three finish line configurations. It is known that ceramic firing of metal copings compromises marginal fit [ 5 ] of metal-ceramic crowns. However, in the present study, porcelain application was not performed, and ceramics firing of SLM copings may show variable outcomes.…”

“…Factors affecting the marginal misfit of metal substructure of metal-ceramic crowns include fabrication techniques (Computer aided design- Computer aided manufacture- CAD-CAM), lost wax technique (LWT), copy-milling), ceramic firing, restoration type, margin design, impression materials, die materials and processing techniques [ 5 ]. The most common fabrication techniques are conventional casting and subtractive manufacturing technologies (SMT) including CAD-CAM [ 6 , 7 ].…”

BDJ Open 2021 - our most successful year to date

“…There were just four papers published reporting the results of ex vivo studies. 15,16,17,18 These outline early pre-clinical studies of new health technologies (new materials, methods and pharmacological interventions) and in vitro studies of existing technologies. These were relatively more frequent in the early days of BDJ Open, but this journal now covers the whole range of dental research.…”