The esthetics and functional integrity of the periodontal tissue may be compromised by dental loss. Immediate implants became a viable option to maintain the periodontal architecture because of their anatomic compatibility with the dental socket and the possibility of eliminating local contamination. This article describes the procedure of immediate implant placement in the anterior maxilla replacing teeth with chronic periapical lesions, which were condemned due to endodontic lesions persisting after failed endodontic treatment and endodontic surgery, and discusses the relationship between the procedure and periapical lesions. Surgical removal of hopeless teeth 11, 12 and 21 was performed conservatively in such a way to preserve the anatomy and gingival esthetics. A second surgical access was gained at the apical level, allowing the debridement of the surgical chamber for elimination of the periapical lesion, visual orientation for setting of the implants and filling of the surgical chamber with xenogenous bovine bone graft. After this procedure, the bone chamber was covered with an absorbent membrane and the healing screws were positioned on the implants. Later, a provisional partial removable denture was installed and the implants were inserted after 6 months. After 3 years of rehabilitation, the implants present satisfactory functional and esthetic conditions, suggesting that immediate implant placement combined with guided bone regeneration may be indicated for replacing teeth lost due to chronic periapical lesions with endodontic failure history in the anterior maxilla.

Two demineralized bovine bone membranes after cleaning and cutting into appropriated size, incorporated with doxycycline (DOX) and tetracycline (TET)were evaluated as controlled drug delivery devices and. The complete release time was 96 h (15 days) with a quick release in the first 12 h, decreasing exponentially to zero when it reaches 96 h. The release system fits in a pseudo second order kinetic model allowing the calculation of relevant parameters such as the initial release kinetics of the drug (h) with values of 0.228 µg g-1 h-1 for DOX and 0.625 µg g-1 h-1 for TET, and a release rate constant (k) 37.66 g mg-1 h-1 for DOX and 43.03 g mg-1 h-1 for TET. The amount released by TET is higher than for the DOX in all the periods analyzed, but with the same desorption profile although any additional treatment on the membranes surface has been made. Both systems can be characterized as a controlled release device, due to their effective retention even long time after the start of experiment. Its use incorporated with antimicrobials agents is an important tool as physical barrier in periodontal regeneration to help combat periodontal pathogens and modulate the inflammatory response of the host, limiting tissue destruction.