[1] Univ Groningen, Dept Oral & Maxillofacial Surg & Maxillofacial Pr, NL-9700 RB Groningen, Netherlands
[2] Univ Med Ctr Groningen, NL-9700 RB Groningen, Netherlands
[3] Hosp Walcherwen, Dept Oral & Maxillofacial Surg, NL-4380 DD Vlissingen, Netherlands
[4] Oosterschelde Hosp, Dept Oral & Maxillofacial Surg, NL-4460 BB Goes, Netherlands
[5] Univ Groningen, No Ctr Healthcare Res, NL-9700 AD Groningen, Netherlands