Extracting a molar leaves a defect which cannot completely be filled out by an implant. The 90 patients are therefore randomised into 3 groups according to how the perimarginal bonedefects around the placed implants are being treated: 1. Bonechips 2. Membrane 3. Bonechips+Membrane. The bonehealing of the defects around the implants are then compared the groups in between. The amount of newly formed bone is being estimated too by digital radiography and subtractionradiography. Furthermore the prognosis for immediate placed implants in molar regions in relation to the method of defectreconstruction one year after crown delivery is also being investigated. All the investigations are conducted with the Ho-hypothesis that there is no difference in the bonehealing the three groups in between.