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Article History

Received: 10 November 2017

Accepted: 29 November 2019

First Online: 23 December 2019

Change Date: 31 January 2023

Change Type: Correction

Change Details: This article has been retracted. Please see the Retraction Notice for more detail:

Change Details: https://doi.org/10.1186/s12903-023-02769-7

Ethics approval and consent to participate

: The authors declare that the Ethics approval and participant consent was not necessary as this study involved the use of a previously-published de-identified database according to national legislation. The Ethics Approval is not applicable.

: Not applicable.

: All the authors declare the absence of any conflict of interest.