Toggle Main Menu Toggle Search

Open Access padlockePrints

Micro-CT Scanning Confirms Acceptable Marginal Fit Of Chairside Composite Crown

Lookup NU author(s): Christopher O'ConnorORCiD, Dr Matthew GermanORCiD, Professor Paula WaterhouseORCiD, Jamie Coulter, Dr Iad GharibORCiD


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Abstract: Objectives: An experimental composite crown (CC) that can be fabricated and delivered chairside has been developed by 3M™. The objective of this in-vitro study was to test the marginal fit of CCs and compare it to to an established crown production method (IPS-e.max-Press; IvoclarVivadent (EMAX).Methods: 21 CC and EMAX crowns were produced on 42 individual plastic lower right premolar teeth prepared for a crown with a 1mm shoulder (model:A3-ZPK-45;Frasaco). Each crown was fabricated then cemented onto the prepared tooth using an ultra light bodied VPS impression material (Imprint™4, 3M™). Each crown was then scanned on an X-ray microscope (XRadia 410 Versa X-ray microscope, Zeiss) at 5.2μm voxel size resolution. Scans were reconstructed (XMReconstructor software, Zeiss) then analysed using Aviso-Fire 8.0(FEI software).The central coordinate of each crown was manually configured then 25 equally spaced vertical sections were generated around its circumference. A single operator manually analysed each section and measured, at 2 points per section, the marginal gap (MG) and absolute marginal discrepancy (MD).The resulting data were non-normally distributed, so group medians and interquartile ranges were calculated. Significant differences were tested using the Mann-Whitney-U-test.Results: The MG of CC (median: 44μm (IQR: 27-68)) were significantly smaller (P=<0.001) than the EMAX (46μm (31-88). Similarly, the MD of CC (median: 109μm (IQR: 76-150)) were significantly smaller (P=<0.001) than the MD of EMAX (186μm IQR=120-249)After excluding from the analysis crowns that we deemed clinically unsatisfactory (median MG=≥120μm, CC (n=1), EMAX (n=3)) then no significant difference (P=0.318) was found between the MG for CC (43μm (IQR:27-61)) or EMAX (42μm (IQR 29-62)).Conclusions: This in-vitro study indicated that CCs produce a clinically acceptable marginal fit. In this study CCs are at least comparable to an existing technology (EMAX) in terms of marginal gap and have a statistically superior absolute marginal discrepancy.

Publication metadata

Author(s): O'Connor CJ, German M, Waterhouse PJ, Coulter J, Gharib I

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: IADR General Session San Francisco California USA

Year of Conference: 2017

Acceptance date: 13/12/2016