Every dentist aims to improve and restore proper function and esthetics in patients affected by periodontitis. Accordingly, it has been argued that periodontally compromised teeth should be treated for as long as possible and should only be extracted when periodontal and endodontic treatments are no longer possible.1,2 The extraction of teeth affected by periodontitis will not resolve the underlying host response problems contributing to the disease. Moreover, periodontally compromised but treated teeth are known to have survival rates equal to the survival rates of implants in well-maintained patients.3 Therefore, the question we should ask ourselves on a daily basis is: should we extract the tooth and replace it with a dental implant? This is a difficult question to answer, as both clinicians and patients are becoming aware that implants are not a permanent solution. Nowadays peri-implantitis reports are increasing, and many factors influence its risk, including bacterial and possible occlusal factors. But when one looks at the evidence, a tooth can last a lifetime if maintained correctly by both the patient and the clinician.
Periodontal regeneration in the beginning
In the past, periodontal regeneration was considered a treatment modality that allowed the patient to keep a tooth that was periodontally involved. The concept arose from the understanding of the healing of a periodontal pocket based on the studies of Murray et al., Hurley et al., and Melcher et al., where they noted that the epithelium had a protective role for the root surface.4-6 The authors also showed that the rapid proliferation of the epithelium and gingival connective tissue formed long junctional epithelium. Later, a study by Nyman et al. demonstrated that the isolation of epithelium and gingival connective tissue from a periodontal defect using a barrier allowed the periodontal defect to heal with bone, periodontal ligament and cementum.7 This study heralded the technique of GTR for periodontal regeneration by first utilizing a non-resorbable expanded polytetrafluoroethylene and later a resorbable collagen membrane placed over a periodontal defect,8 sometimes filled with a bone graft.9,10
The bony defects that allow greater predictably of periodontal regeneration are three- and two-wall defects. Three-wall defects provide the highest amount of regeneration due to the number of walls surrounding the bony defects able to stabilize the blood clot for proper healing and maturation and able to contribute the most bone cells for bony healing at the site. Over time surgical technique and technology have advanced to the point where we are now raising the tissues only slightly using the MIST as suggested by Cortellini and Tonetti.11 The concept focuses on not elevating the gingiva too much to evaluate and treat periodontal defects. If the defect extends to another tooth or is circumferential, then the gingival tissues can be elevated further to expose the defect, and more traditional periodontal regeneration techniques can be performed by placing a bovine bone graft and a collagen membrane. On the other hand, if the bony defect is localized, then curetting the defect and assessing if the clot can be stabilized by the flap alone or by placing a bovine bone graft, sometimes mixed with enamel matrix proteins, enhances the outcome though less invasive periodontal regeneration. (Fig. 1)
Raising large periodontal flaps is turning into a treatment of the past, while performing minimal flaps is growing more common in everyday practice. Due to greater predictably of the techniques and better understanding of the biology of periodontal disease and healing, we can now reduce the morbidity involved with more extensive surgical procedures, and we can avoid placing dental implants in younger patients – improving the prognosis for teeth before considering implants. And it is clear that we need to acknowledge periodontal regeneration as a predictable modality.