1 Department of Oral Cell Biology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Amsterdam, the Netherlands; Department of Anatomy, Dental Faculty, Chulalongkorn University, Bangkok, Thailand. Electronic address: veverts@gmail.com.
2 Department of Periodontology, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University, Amsterdam, the Netherlands.