This exploratory study is the first study in a clinical program where the overall objective is to develop a novel pharmaceutical therapy comprising local administration of GM-CSF for the treatment of periodontitis. The project hypothesis is based on GM-CSF's antibacterial and putative bone regeneration properties. Periodontitis is the major cause of tooth loss in people over 35 years of age. An effective pharmacological treatment is today lacking and the actual therapy would represent a new treatment option for the large patient group suffering from the disease.