In this chapter, the results from a relatively recently performed systematic appraisal of the literature on the long-term outcome of regenerative periodontal treatment in intrabony defects are presented. Periodontal regenerative procedures in intrabony defects yield significantly better clinical outcomes compared with conventional surgery and result in high rates of tooth retention on a medium- to long-term basis. Combination approaches seem, in general, more efficacious compared with monotherapy.
Periodontal regenerative procedures yield significantly better clinical outcomes in intrabony defects compared with open flap debridement, on the medium- to long-term.
Combination approaches, including the use of a bone graft seem to be more efficacious compared with monotherapy.
Periodontal regenerative procedures result in higher rates of tooth preservation compared with open flap debridement on the medium- to long-term.
Why periodontal regenerative procedures?
To arrest progressive attachment loss and/or prevent further disease progression, control of the infection caused by the oral bacterial biofilm remains the primary aim of periodontal treatment. For most patients and teeth/sites, this goal can be commonly achieved through proper and adequate self-performed oral hygiene and professionally performed nonsurgical and/or conventional surgical periodontal treatment. In the clinic, this translates into reduced probing pocket depths (PD) and gain in clinical attachment level (CAL), reduced tendency to bleeding on probing (BoP), and stable/increased bone levels, compared with pretreatment levels. Nevertheless, residual (deep) PD can still be present following nonsurgical and/or conventional surgical periodontal therapy, commonly in teeth/sites with deep intrabony defects and/or deep furcation involvements. Deep PD after periodontal therapy is indeed associated with an increased risk for disease progression and tooth loss. In a long-term study, deep residual PD or a deep furcation involvement (ie, class II and III) after treatment has been associated with an exponential higher risk for periodontitis progression and tooth loss. Specifically, a greater than 10 times higher risk for tooth loss has been reported for teeth with a residual PD greater than or equal to 6 mm compared with teeth with a residual PD of less than or equal to 3 mm, whereas teeth with a class II or III furcation involvement showed about 5 to 13 times higher risk for tooth loss compared with teeth with no furcation involvement. Deep defects can be managed efficiently with either resective or regenerative approaches. Resective approaches, however, have the drawback of extensive soft tissue recession and often further loss of attachment. Thus, a variety of surgical regenerative treatment protocols have been developed and refined during the last 3 to 4 decades, with the aim to enhance treatment outcomes and at the same time to evade/reduce the aforementioned shortcomings of conventional and/or resective approaches. Indeed, significantly better clinical (ie, larger CAL gains, shallower residual PD, and less recession) and radiographic results (ie, larger bone level gain and reduced residual intrabony defects) have been collectively reported after regenerative periodontal procedures compared with conventional surgical procedures. Periodontal regenerative procedures—as the term coins—result also in significantly better histologic outcomes compared with conventional surgery (ie, larger amounts of new cementum, periodontal ligament, and alveolar bone) if correct case selection, appropriate execution of treatment, and undisturbed healing are provided (for review see , ).
Longevity of treatment
The overall goal of periodontal therapy is to reestablish periodontal health and contribute to the overall oral well-being, that is, having only a few sites with bleeding on probing and no teeth with deep PD, the teeth are capable of functioning trouble-free, and preferably there is a satisfactory esthetic appearance. This goal should be achieved by preserving as many teeth as possible, for as long as possible. It is well established that the clinical conditions obtained after conventional periodontal therapy, nonsurgical or surgical, can be maintained for several decades, provided that the patient is keeping an adequate oral hygiene level. , Thus, if one treatment should be considered better than conventional periodontal therapy, the results of this treatment should also be maintainable for a long period. In this context, the histologic outcomes obtained after periodontal regenerative procedures show variability in terms of the relative tissue composition of the various constituents of the periodontium, mainly depending on the use and/or the type of biomaterial and/or bone substitute. , For example, the use of deproteinized bovine bone—a barely resorbable material—results in a regenerated periodontium, where the new bone tissue contains a substantial number of the grafted particles after completed healing , ( Fig. 1 ). It is thus relevant to assess the long-term outcome of the various periodontal regenerative procedures and the possible impact of presence of graft substitute particles within the tissues. In the following section, results from a relatively recently performed systematic appraisal of the literature on the long-term outcome of regenerative periodontal treatment in intrabony defects are shortly discussed. In the recent systematic literature search, only publications from randomized clinical trials on regenerative periodontal treatment with an average follow-up greater than or equal to 3 years, but with a minimum follow-up greater than or equal to 2 years, were identified, which is already setting the bar high for the decision-making for the success of regenerative procedures. In perspective, what is appropriate longevity of treatment may be a matter of debate, and aspects of professional effort and cost-effectiveness, as well as patient-related outcomes including suffering should be taken into account. However, the success of any treatment modality should be tested and established over time.