The management of tissue destruction caused by periodontitis has grown significantly as a result of continuous developments in the field of guided tissue regeneration (GTR) and guided bone regeneration (GBR). A membrane is utilized as a scaffold to establish a secure surgical microenvironment capable of inducing progenitor cell differentiation for GTR. These mat-like GTR/GBR membranes^[1] strategically isolate the periodontal defect and function as a physical barrier to avoid gingival epithelial cell invasion.

To be used in vivo, these membranes must be biocompatible to allow integration with the host tissues without inducing inflammatory reactions, have appropriate biodegradability, sufficient strength to prevent membrane collapse and hold their barrier function.^[2,3] There is considerable doubt that no unique biomaterial can effectively direct the simultaneous growth of several tissue types, particularly in pervasive periodontal defects.

The periosteum is a fragile tissue that covers the outer surface of bones comprising three zones; zone-1, commonly referred to as the cambium layer, is located closest to the bone and mostly consists of osteoblasts, osteoblast progenitor cells, and multipotent stem cells. In zone-2, also known as the matrix layer which makes the periosteum highly vascular contains fibroblasts, fibroblast progenitor cells, and a thick vascular plexus. Zone-3 is the outermost layer and is also referred to as the collagenous layer as it contains thick collagen fibers. The combination of zones 2 and 3 forms the fibrous layer. These periosteal stem cells and progenitor cells have the distinct potential to differentiate into a plethora of precursor cells in all age groups.^[4,5] As broadly conceived, from a structural point of view, the periosteum is a bilayer membrane, and for regeneration, the preservation of this highly vascularized tissue is critical.^[4,6] In addition, periosteal cells also yield vascular endothelial growth factor, which promotes angiogenesis and healing.^[5-8] It is also believed that the periosteal layer is the one with maximum potential to regenerate lost periodontal tissues.^[9,10] The periosteum is potentially a more appropriate bio-membrane that can be applied with minimal complications as a barrier membrane in GTR.

By exhibiting the aforementioned properties, the periosteum potentially reveals a highly viable alternative to a commercially available biomaterial in GTR. The use of the periosteum as a barrier membrane in periodontal regeneration dates back to studies^[11] by Ellegaard et al.^[9], Lekovik et al.,^[8] and Kwan et al.,^[12] in the 1970s–1990s that effectively treated gingival recessions, intrabony defects, and furcation defects using the periosteum harvested from the palate. This technique was further modified by Mahajan in 2009^[13] where he described a periosteal pedicle graft (PPG) that acts as an autogenous graft for recession coverage. This provides continuous vascular supply to the graft over the denuded avascular root surface and stabilizes the blood clot that heals the surgical wound.

Various comparative studies were carried out to understand the potential of the PPG over other conventional methods such as connective tissue graft (CTG), coronally advanced flap (CAF) technique, and vestibular incision subperiosteal tunneling approach (VISTA) technique^[14] for recession coverage. The PPG technique was also used and compared with resorbable collagen membranes for GTR procedures^[15] for the management of furcation defects, intrabony defects, ridge augmentation,^[16,17] and also maxillary alveolar clefts.^[18] Open flap debridement (OFD) alone and with bone grafts, and resorbable collagen membranes were all reviewed with the PPG technique to understand the advantages and draw accurate comparisons.

Based on the hypothesis that the periosteum acts as a reservoir of stem cells,^[10,17] also known as the “umbilical cord”^[19] of bone, this systematic review and meta-analysis aims to establish the clinical efficacy of the PPG as a barrier membrane over other traditional resorbable collagen membranes in GTR for gingival recession, intrabony, and furcation defects.

Through the years of research on GTR, various strategies have been experimented with to find the most efficient barrier to achieving successful regeneration excluding epithelial cells.^[3,6] Periosteum vessels develop a new microcirculation where there has been an injury to the bone. The new bone is formed as the result of relative movements of the bone exerted on the periosteum by rearrangement of osteoblasts along the direction of tension release. The undifferentiated layer thus plays a crucial regulatory role in bone remodeling because of the delayed reaction and visible structural changes in the mid-zone that act as a buffer. This process of bone regeneration through the periosteum has been termed “osteodistraction” where there is an increase in the surrounding adjacent bone and tissue volume.^[4,5]

This review demonstrates that PPG as a barrier membrane has given an equivalent outcome to comparators in terms of gingival RD, PD, and a significant gain in the KTW, root coverage, and CAL (Nisha et al.^[30], Mahajan et al.^[31], Paramashivaiah et al.^[29], Dandu et al.^[14], Bhavana et al.^[28]). The use of PPG along with a CAF or with adjuncts such as low-level lasers,^[29] platelet-rich plasma^[38] or platelet-rich fibrin^[39] and additional growth factors^[35] have also been implied with better results and higher predictability for recession coverage. However, when the mean root coverage achieved was compared between PPG and CTG, it was in favor of PPG in one study^[31] and favored CGT in another.^[27] It could be cautiously interpreted that PPG is equally efficient as that of the existing “gold standard,” i.e., CTG in recession management. Of all the included studies, only one article^[30] discussed increase in gingival thickness (GT), and that favored PPG. It is also to be noted from our review that GT is an important parameter for predictable root coverage and should be considered an important variable in future research.

Furcation defects and intrabony defects have traditionally been treated with OFD or GBR with collagen membranes. The PPG technique used for recession coverage is slightly modified when used in cases of furcation or intrabony defects. The infected pocket lining causes destruction of the underlying periosteum so the periosteum is displaced from the mesial direction of the affected site with a distal pedicle, as described by Verma et al. for such defects.^[33] From the results of this review, it could be inferred that the PPG used as a membrane with or without bone substitutes resulted in a reduction in PD, gain in CAL, and 0.67 times more bone fill in furcation defects. Hazzaa et al.^[32] further evaluated histological sections and reported a well-organized collagen fiber arrangement and the presence of metabolically activated fibroblasts with the use of a combination of PPG and bone substitute. Though only two studies met our criteria, it could be interpreted that PPG enhanced the predictability of furcation management.

The treatment outcome for intrabony defects is affected largely by the morphology of the defect. Depending on the defect site and containability, the treatment of choice is always GTR (Murphy et al., 2003),^[35,40] i.e., with a collagen membrane.^[41] When using PPG for the treatment of intrabony defects, the PPG acts as a barrier or scaffold for GTR.^[37] Among the included five studies, two studies^[34,35] show a significant reduction in the PD and gain in CAL when a PPG is used, while Ghallab et al.^[36] observed no significant difference in the parameters after OFD alone versus PPG. One study (Singhal et al.)^[22] showed no significant difference in PD or gain in CAL when a PPG was combined with an alloplast. Paolantonio et al.^[37] compared OFD alone, OFD with a collagen membrane, and OFD with a PPG combined with an autograft. This study showed that the PPG is on par with the GTR membrane when compared against OFD alone.

The periosteum stimulates bone formation in furcation and intrabony defects as it acts like a graft with sufficient soft tissue to avoid a collapse into the defect while maintaining the blood clot for early healing. When a bone graft (allograft or autograft) is added to this scenario,^[32] the PPG acts as a GTR membrane similar to that of a resorbable collagen membrane that prevents epithelial downgrowth and bone graft resorption. Furthermore, the PPG will not cause any severe consequences on exposure, while collagen membrane exposure will have repercussions. The comparison of PPG with a nonresorbable membrane has not been evaluated in this study as the application of a nonresorbable membrane in GTR is justified in severe intrabony or furcation defects and in GBR for extensive bone augmentation. Hence, when rigid external support is required for the bone graft contained within the defect, non-resorbable membranes may be used since the defect itself does not have enough bony wall support. Besides, an additional surgery is required to remove the said membrane once an adequate bone fill or healing is achieved over a span of 6–12 months.^[35,41] The comparison of PPG with non-resorbable membranes will be the same as comparing resorbable with nonresorbable membranes and since the rationale for both are different, this study did not include this comparison.

Radiographic bone fill seemed to be best when PPG was used with a bone graft. GTR with PPG membrane as a standalone therapy was closely followed as the next best option, and the least preferred was OFD alone.^[34] Even histological studies have been conducted by Singhal et al.,^[22] who used a combination of alloplasts as defect fillers, especially in containable defects (two/three-walled) and also in non-containable defects (one-walled) with PPG. The use of PPG had superior improvements in clinical outcomes as compared to conventional methods and also had the closest architecture to the normal periodontium (Steiner et al.).^[17] However, both the studies included in this review have accounted only for linear measurements, whereas a cross-sectional assessment could have given a better evaluation of the bone fill outcome.

Although the PPG technique is less complicated than CTG harvesting and more effective than an OFD, its limitations are equally difficult to manage. Any damage to the periosteum while separating from the flap or alveolar bone will alter the formation of new bone, giving less optimized results. Careful handling of tissues is mandatory for controlled bleeding. This technique is contraindicated in patients with a thin gingival phenotype as it may cause a tear while reflecting a split-thickness flap. Once the periosteum is reflected, it may leave behind a “dead space” into which blood and inflammatory fluid can flow. In such cases, it may get complicated if the surgical site is in the canine-premolar area, where the blood accumulates and reaches the infraorbital areas causing a hematoma. Lengthy interventions may cause significant tissue damage and bleeding, leading to fluid buildup in interstitial spaces.^[42]

Advanced periodontal defects such as Miller’s Class III/IV recessions, Grade III furcation involvements, and one-walled intrabony defects are another dilemma that may be discussed. Depending on the prognosis and a thorough understanding of such defects, a strategy for treatment planning and management may be employed. The use of PPG may not be as applicable in such defects since there will be a limited amount of soft tissue and blood supply to create the necessary pedicle from the periosteum. In severe intrabony (one-walled) and furcation (Grade III) defects, no grafts can be accommodated in the site and hence an OFD and ressective surgery may be employed. For recession defects with interproximal bone loss (Miller’s Class III/IV), the chances of achieving a complete root coverage are already questionable and hence two two-stage surgery approaches may be considered. Further clinical research is required to confirm the effectiveness of using PPG in such advanced defects.

According to our analysis, the PPG can be applied as an autogenous, pluripotent, and safe membrane for the mentioned defects. However, we notice several limitations in the current meta-analysis that should be declared. First of all, the number of RCTs and controlled clinical trials was less in number. Second, most of the included studies showed a moderate-to-high ROB. Third, high heterogeneity is seen due to differences in study design, patient selection methods, parameters recorded, defect morphologies, and follow-up periods. All the aforementioned limitations prevented us from drawing a definitive conclusion on the superiority of PPG as a gold standard over commercially available resorbable collagen barrier membranes. Nevertheless, the use of PPG as a membrane in regenerative approaches still gives promising results. There is a need for more randomized clinical trials with larger sample size and longer follow-ups to provide more conclusive evidence.

Within the limitations of this systematic review and meta-analysis, it can be interpreted that:

Although PPG is technique-sensitive, it avoids a second surgery (like in a non-resorbable collagen membrane)^[41] and is abundant in pluripotent cells