Funding for this research was provided by:
Swiss Association of Dentomaxillofacial Radiology (15/01)
Text and Data Mining valid from 2018-07-17
Received: 1 May 2018
Accepted: 27 June 2018
First Online: 17 July 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This study was reviewed and approved by the local ethics committee of the State of Bern, Switzerland (approval number 384/14). All procedures in this retrospective study were conducted in accordance with the Declaration of Helsinki (1964) and its later amendments.
: For this type of study (retrospective study), formal consent is not required.