Periodontal regeneration in intra-bony defects has been successfully attempted with a variety of different approaches. Human and animal histological findings support the potential of barrier membranes, demineralized freeze-dried bone allograft (DFDBA), combination of barrier membranes and grafts, and enamel matrix derivative (EMD) to induce periodontal regeneration. In addition, controlled clinical trials report that these approaches provide added benefits in terms of clinical attachment level (CAL) gain as compared to access flap alone. Comparisons among some of the regenerative approaches failed to demonstrate a clear superiority of any of the tested materials.

The number of residual bony walls defining the defect seems to affect outcomes. Non-resorbable (ePTFE and titanium-reinforced ePTFE) barrier membranes and bioabsorbable barriers supported by a graft do not seem to be affected by the number of residual bony walls of the defect, while EMD results in better outcomes in 3-wall defects. Bioabsorbable barriers and nonresorbable ePTFE barriers as well as EMD are influenced by the width of the intrabony defect.

The existing evidence, therefore, does not provide clinicians with a clear indication for choosing a single approach among the different procedures. In addition, all the cited studies have shown a substantial degree of variability in terms of CAL gains, reporting failures, or unsatisfactory outcomes in part of the treated population. Research conducted mostly in the past decade has clearly established that the variability observed in outcomes of periodontal regenerative procedures is dependent on a variety of patient, defect, and surgical factors. Patient factors include cigarette smoking, residual periodontal infection, and oral hygiene. Among the defect anatomy-associated factors, depth of the intrabony component of the defect and/or probing depth are consistently found to be relevant. The number of residual bony walls defining the defect seems to affect outcomes. Non-resorbable (ePTFE and titanium-reinforced ePTFE) barrier membranes and bioabsorbable barriers supported by a graft do not seem to be affected by the number of residual bony walls of the defect, while EMD results in better outcomes in 3-wall defects. Bioabsorbable barriers and nonresorbable ePTFE barriers as well as EMD are influenced by the width of the intrabony defect.

Among the technical/surgical factors, membrane exposure and contamination have been associated with reduced outcomes. Similar problems were also encountered with bone grafting. Reduced outcomes were also observed when the regenerated tissue was not properly protected with the flap when non-resorbable barrier membranes were removed.

A controlled clinical trial demonstrated that the combination of a papilla preservation flap and titanium reinforced ePTFE membrane resulted in greater amounts of clinical attachment level gains compared to a conventional flap approach associated with an ePTFE membrane. This evidence strongly suggests that optimization of the surgical approach and control of surgical variables, particularly in relation to flap design and management and selection of the regenerative material, could improve outcomes. In the context of guided tissue regeneration (GTR), several specific flap designs aimed at the full preservation of the soft tissues during access to the defect have been described. Experimental testing of these regenerative flaps reported great improvements in achieving primary closure during the surgical session with optimal interdental closure being obtained in virtually all cases. During the subsequent healing, however, dehiscence of the interdental tissue and membrane exposure was observed in up to a third of the cases. The ability to accomplish and maintain primary closure of the tissues over a GTR membrane was further improved by the use of a microsurgical approach that resulted in maintenance of primary wound closure in 92.3% of the treated sites for the whole healing period.

An attempt has been made to build an evidence-based regenerative strategy to guide clinicians through a decision process to optimize the clinical outcomes of periodontal regeneration in intrabony defects by carefully pooling together the information coming from this body of evidence. Key steps of this process are the careful evaluation of the patient and the defect, the ability to access the defect with a papilla preservation flap, selecting the most appropriate regenerative technology, and the ability to seal the regenerating wound from the contaminated oral environment with optimal suturing techniques. The aim of the present case cohort study was to evaluate the clinical performance of an evidence-based regenerative strategy in the treatment of deep intrabony defects.