Coronally Advanced Entire-Papilla Preservation Flap with Recombinant Human Platelet-Derived Growth Factor and Freeze-Dried Bone Allograft for Treatment of Isolated Intrabony Defect

Introduction

Periodontal disease is characterized by the progressive destruction of the tooth-supporting structures and the formation of a pathological pocket [1]. The goal of periodontal therapy is to arrest periodontal disease progression and restore lost periodontal structures [2]. Conventional periodontal therapy, including scaling and root planing, and flap surgery, can reduce inflammation and arrest the progression of the disease; however, these approaches may fail to predictably restore lost periodontal tissues. Intrabony defects resulting from vertical bone loss present significant challenges in periodontal regeneration due to their complex morphology and limited vascular supply [3]. Regenerative approaches utilizing bone substitutes, barrier membranes, and biological mediators have been developed to address these challenges [4,5].

Achieving primary wound closure is essential for successful periodontal regeneration, as it serves to maintain vascular supply and optimize healing [6]. Traditional flap designs often involve interdental papilla incisions that may jeopardize vascular integrity and impair soft tissue healing in regenerative procedures. To address these limitations, techniques such as the Modified Papilla Preservation Technique and Simplified Papilla Preservation Technique have been introduced [7–9]. Minimally invasive techniques such as the Modified Minimally Invasive Technique and Single Flap Approach have also shown potential in improving clinical outcomes and reducing postoperative morbidity [10–12].

The entire-papilla preservation (EPP) technique provides a minimally invasive alternative that maintains papillary integrity while facilitating defect access through a tunnel approach [13]. Studies have shown that EPP may facilitate primary wound closure, reduce the risk of regenerative biomaterial exposure, and enhance both clinical and radiographic outcomes [14–17]. A modification of this technique, coronally advanced EPP (CA-EPP) flap, incorporates connective tissue grafts to stabilize the gingival margin, increase tissue thickness, and reduce the risk of recession [18].

In addition to surgical flap design, the use of biologically active regenerative materials has been associated with improved outcomes in periodontal regeneration, including a reduction in probing depth and gain in clinical attachment [19,20]. Among these biologically active regenerative materials, platelet-derived growth factor has been widely studied because of its ability to stimulate angiogenesis, fibroblast proliferation, and osteoblast differentiation [21,22]. When combined with freeze-dried bone allograft, platelet-derived growth factor contributes to an osteoconductive and osteoinductive environment that may support new bone formation [23,24].

This case report describes the use of a coronally advanced modification of the EPP technique combined with recombinant human platelet-derived growth factor (rhPDGF-BB) and freeze-dried bone allograft for the treatment of a deep intrabony defect in the esthetic zone. The approach was selected to optimize soft tissue preservation and promote periodontal regeneration. Clinical observations suggest that this minimally invasive technique may offer potential clinical applicability in the management of intrabony defects.

Case Report

A male patient, aged 36, was referred by a general dentist for periodontitis treatment. The patient’s dental history included multiple dental restorations and extractions due to periodontal disease, poor oral hygiene, and a smoking habit. A comprehensive periodontal evaluation was conducted, including full periodontal charting and full-mouth radiographic assessment, which revealed a deep intrabony defect on the mesial surface of the upper right central incisor (tooth #11, Fédération Dentaire Internationale [FDI] notation), with a 9 mm probing depth, bleeding on probing, and grade 1 mobility (Figure 1A). Radiographic examination showed vertical bone loss extending to the middle third of the root (Figure 1B). The patient was diagnosed with periodontitis, Stage IV, Grade C, according to the 2017 World Workshop classification [25].

The patient received 3 sessions of professional scaling and root planing at 3-month intervals before the surgical procedure. However, no improvement was observed, and the probing depth at the mesial surface of tooth #11 persisted at 9 mm. Following multiple oral hygiene reinforcement sessions, the patient demonstrated improved oral hygiene routines by brushing twice daily using the modified Bass technique and reportedly flossing once daily. Additionally, the patient completed a smoking cessation program and had quit smoking 3 months before the procedure. The coronally advanced EPP technique was planned with rhPDGF-BB and freeze-dried bone allograft to treat the intrabony defect related to the mesial surface of #11.

Local anesthesia was administered at the defect site through local infiltration using 2% lidocaine with 1: 100 000 epinephrine. A buccal intrasulcular incision was made on tooth #11 and adjacent tooth #21 using an SM67 microblade (Swann-Morton, England). A horizontal incision was made at the base of the papilla distal to the defect and extended into the sulcus of tooth #11 (Figure 2A). A buccal vertical releasing incision was made at the distal-line angle of #11, extending beyond the mucogingival junction. The flap was initially elevated as a partial-thickness dissection, extending 2 mm apical to the horizontal incision, and subsequently converted to a full-thickness elevation past the mucogingival junction, using a microsurgical periosteal elevator in a mesial direction. The mesial interdental papilla was tunneled and elevated as a full-thickness flap using tunneling instruments (Allen Oral Plastic Kit, Hu-Friedy). After flap elevation, the 2-wall intrabony defect was thoroughly degranulated, followed by root planing using an ultrasonic scaler and Gracey curettes (Figure 2B). The site was irrigated with sterile saline to remove residual debris.

Next, rhPDGF-BB (GEM 21S, Lynch Biologics LLC, Franklin, TN, USA) was applied to the exposed root surfaces and mixed with freeze-dried bone allograft (Oragraft, Lifenet Health), and then packed into the defect (Figure 2C). A de-epithelialized connective tissue graft was harvested from the palate, measuring 18 mm mesiodistally, 5 mm apicocoronally, and approximately 1 mm in thickness. The palatal wound at the donor site was covered with collagen matrix and stabilized using compression sutures. The connective tissue graft was secured over the grafted defect site using 2 simple interrupted sutures under the tunneled flap (polydioxanone 6/0, 12-mm 3/8) (Figure 2D). The distal papilla of tooth #11 was de-epithelialized, and a periosteal-releasing incision was made at the base of the buccal flap using a 15c blade. The buccal flap was coronally advanced and secured using a vertical suspension suture at the mesial papilla and a sling suture at the distal papilla (polypropylene 6/0, 12-mm 3/8). Additional simple interrupted sutures were placed to close the vertical incision (polypropylene 6/0, 12-mm 3/8), achieving tension-free primary closure (Figure 2E).

The patient received detailed postoperative instructions, including avoiding brushing, flossing, and chewing on the treated area for 2 weeks. Postoperative medications included amoxicillin 500 mg 3 times daily for 7 days, ibuprofen 400 mg every 8 hours as needed, and chlorhexidine gluconate 0.2% mouth rinse twice daily for 2 weeks. Sutures were removed at the 2-week follow-up, and the patient was instructed to use an ultra-soft toothbrush for 2 weeks before resuming regular brushing. The patient was scheduled for a 2-month follow-up visit to monitor healing.

At the 6-month evaluation, the treated site showed stable soft tissue, absence of inflammation or recession, and a reduction in probing depth from 9 to 3 mm (Figure 3A). The radiographic assessment demonstrated notable bone fill within the defect (Figure 3B). No postoperative complications were reported.

Discussion

This case presents the application of the coronally advanced EPP technique in combination with platelet-derived growth factor and freeze-dried bone allograft for the regenerative treatment of an isolated deep intrabony defect. Flap elevation techniques involving papillary incisions may disrupt the vascular supply, potentially increasing the risk of gingival recession and delaying wound healing. In contrast, tunneled surgical approaches may help preserve the interdental papilla, thereby reducing postoperative morbidity and improving clinical outcomes [13,14,19].

In the current case, the probing depth decreased from 9 to 3 mm, and radiographic imaging revealed bone fill, which may suggest a favorable regenerative response. The combined effects of rhPDGF-BB and freeze-dried bone allograft may have contributed to this outcome. Platelet-derived growth factor is a mitogen known to promote cellular proliferation and osteogenesis, while freeze-dried bone allograft serves as an osteoconductive scaffold that supports new bone formation and defect resolution [26,27]. Furthermore, the utilization of a connective tissue graft with the coronally advanced flap technique may have enhanced surgical outcomes by increasing soft tissue thickness, stabilizing the interdental papilla, and promoting gingival margin stability [18]. This combined approach allows for the simultaneous reconstruction of hard and soft tissues, contributing to favorable regenerative and esthetic results.

Patient-related factors such as smoking and oral hygiene compliance can influence the outcome of periodontal regeneration [6]. Smoking can impair vascularization, delay wound healing, and compromise regenerative potential, which may result in reduced clinical attachment gain and less predictable results [28]. In the present case, the patient’s smoking cessation and improved oral hygiene before the procedure likely contributed to a favorable healing response.

The effectiveness of buccal flap elevation alone was sufficient in this case; however, this approach may limit access in cases with palatal intrabony defects. To address this limitation, Ogawa et al (2023) proposed the double-sided EPP technique, which involves a palatal incision to improve defect access [29]. Although not necessary in our case, this modification could be considered in future cases involving more complex defects. The present findings are consistent with case series by Sanz et al (2024) [17], Gorski et al (2023) [19], Acipinar et al (2024) [20], and Rasperini et al (2024) [18], which reported clinical improvement using variations of the EPP technique. Gorski et al (2023) demonstrated favorable clinical outcomes using the EPP technique with enamel matrix derivatives and allografts, supporting its efficacy in promoting periodontal regeneration419]. Rasperini et al (2024) reported the potential benefits of connective tissue grafting in enhancing soft tissue stability when using the coronally advanced EPP technique approach [18]. Our case similarly demonstrates the potential of combining platelet-derived growth factor and freeze-dried bone allograft with coronally advanced EPP technique to support both hard and soft tissue regeneration.

Although the short-term results in this case were favorable, the absence of long-term follow-up limited our ability to assess the durability of the clinical and radiographic improvements observed. As periodontal regeneration may progress over time, extended follow-up is necessary to confirm the longevity of these results [30]. Additional studies with larger cohorts and longer observation periods are recommended to validate these findings and further optimize regenerative treatment strategies for complex intrabony defects.

Conclusions

This case report suggests that the minimally invasive flap design, in combination with rhPDGF-BB and a bone substitute, may have supported periodontal regeneration, as reflected by the observed reduction in probing depth and radiographic bone fill at 6 months postoperatively. This technique maintained vascular supply, preserved soft tissue integrity, and provided a favorable environment for healing, potentially contributing to favorable clinical and esthetic outcomes. However, given the limitations of a single case and the short-term follow-up, further studies are warranted to confirm the reproducibility and long-term effectiveness of this approach.