Abstract

Introduction: Periodontitis is a multifactorial disease primarily associated with biofilm accumulation, leading to progressive loss of periodontal support and the formation of bone defects. Although traditionally considered independent entities, clinical and anatomical evidence has demonstrated a close relationship between periodontal and pulpal pathologies, particularly in endo-periodontal lesions. According to recent classifications, these lesions may have a primary endodontic, periodontal or combined etiology and are characterized by anatomical communication between the pulp and the periodontium through apical foramina, dentinal tubules and lateral canals. Disease progression facilitates the migration of bacteria and toxins between the tissues, exacerbating their destruction. Therefore, differential diagnosis is essential for defining an appropriate treatment, which must be comprehensive and include both root canal disinfection and periodontal regeneration. Guided Tissue Regeneration (GTR), using collagen membranes and bone substitutes, has proven to be an effective technique for promoting healing and restoring functionality in areas affected by bone and soft tissue destruction, enabling the regeneration of damaged periodontal tissues.

Case Report: A 51-year-old female patient presented to the Postgraduate Program in Periodontics and Implantology at UJED seeking to preserve tooth 1.2. Clinical and radiographic examination revealed a defective restoration with intraosseous crater-type root exposure and deep probing depth. The diagnosis was generalized periodontitis, stage III, grade B. Additionally, the endodontic diagnosis was previously treated tooth with asymptomatic apical periodontitis and an endo-periodontal lesion type V according to Simon, Glick and Frank. Nonsurgical retreatment and guided tissue regeneration were indicated to improve the prognosis of the tooth.

Objective: To evaluate the clinical and radiographic outcomes of guided tissue regeneration in the treatment of endo-periodontal lesions with infraosseous defects through a detailed analysis of the therapeutic response. The aim is to determine whether this technique significantly enhances bone regeneration and periodontal health, contributing to improved prognosis in affected patients.

Conclusion: At 6 months postoperatively, satisfactory bone and soft tissue regeneration was observed in the treated tooth, with significant clinical and radiographic improvement. There was evidence of bone level gain, reduction in probing depth and decreased tooth mobility, indicating favorable periodontal recovery.

Keywords: Endo-Periodontal Lesion; Guided Tissue Regeneration; Membrane; Intraosseous Defect; Bone Substitute

Introduction

Periodontitis is a multifactorial disease primarily associated with the presence of biofilm and characterized by the progressive loss of periodontal support. One of its key consequences is the formation of bone defects, caused by biofilm and calculus accumulation on the hard wall of the tooth, as well as the infiltration of leukocytes and lymphocytes on the soft wall of the periodontal pocket. These interactions promote pathological migration of the junctional epithelium, connective tissue and bone, thereby contributing to disease progression [1]. Historically, periodontal and pulpal pathologies have been considered independent entities. However, clinical and anatomical evidence has demonstrated a significant relationship between them, especially in endo-periodontal lesions. According to the classification by Simon Glick de, combined lesions are defined by the simultaneous involvement of both periodontal and pulpal tissues, with a primary endodontic, periodontal or combined etiology [2,3]. More recently, Herrera, Retamal-Valdes have proposed a classification based on the presence or absence of periodontal disease and root damage, including conditions such as root fractures, cracks, perforations and resorptions [4]. Anatomical communication between the pulp and the periodontium occurs through the apical foramen, dentinal tubules, lateral and accessory canals and in multirooted teeth, via the furcation area. These pathways allow inflammatory processes originating in deep periodontal tissues to spread toward the pulp, especially when periodontal disease reaches the apical region or when root surfaces become exposed in advanced stages (III and IV) of the disease [3]. The progression of bone and periodontal ligament destruction can compromise the apical foramen, allowing the migration of bacteria, toxins and endotoxins into the root canal system. The resulting intraradicular infection can further exacerbate periodontal breakdown via retrograde dissemination of toxic and bacterial byproducts, thereby establishing a combined-origin endo-periodontal lesion. Differential diagnosis between endodontic and periodontal diseases is critical, as treatment strategies differ significantly depending on the lesion’s origin. A successful and comprehensive treatment approach requires not only proper disinfection, instrumentation, irrigation and obturation of the root canal system, but also appropriate periodontal intervention to stabilize and regenerate the affected tissues. Proper endodontic therapy is essential to eliminate the infection source and prevent further disease progression, thus creating favorable conditions for periodontal healing. A prominent therapeutic option in cases of endo-periodontal lesions is Guided Tissue Regeneration (GTR). This technique involves the use of biomaterials such as collagen membranes that act as physical barriers, preventing the ingrowth and proliferation of epithelial cells that may interfere with the regeneration of periodontal tissues. Additionally, bone substitutes serve as scaffolds that support the formation of new bone tissue, thereby facilitating a more effective restoration of the destroyed osseous structures. The combination of effective endodontic therapy and appropriate periodontal intervention, including GTR, is essential to achieve successful outcomes and improve the prognosis of affected teeth. This approach promotes periodontal tissue regeneration, facilitating healing and restoring function in areas with significant bone and soft tissue destruction [5-10].

Case Description

The patient’s personal medical history revealed no relevant pathological or non-pathological conditions and she reported no current medication use. Her family history included cancer in both maternal and paternal grandparents. Intraoral clinical examination showed, in general, the presence of maladapted amalgam restorations, carious lesions and Cairo Class I gingival recessions (2011 classification) in teeth #46, #47 and #16 [11]. In the area of interest specifically tooth #12-a metal-ceramic crown with root exposure was observed on both the buccal and palatal aspects, along with dental malposition (Fig. 1A). Radiographic analysis of tooth #12 revealed radiopaque areas within the root canal consistent with a previous endodontic treatment, as well as the presence of a metallic post. Bone loss extending to the apical third was evident, with an intraosseous crater-type defect according to the Goldman and Cohen classification (Fig. 1) [3]. Initial periodontal treatment (Phase I) was started, yielding a plaque control index of 24%, which is considered poor according to O’Leary’s index [12]. Periodontal probing revealed pocket depths of up to 7 mm. A diagnosis of generalized Stage III, Grade B periodontitis was established (Fig. 2). From an endodontic perspective, tooth #12 was diagnosed as previously treated with asymptomatic apical periodontitis, corresponding to a type V endo-periodontal lesion and was assigned a poor individual prognosis. As part of Phase II of periodontal therapy, endodontic retreatment of tooth #12 was planned, along with Guided Tissue Regeneration (GTR) using a collagen membrane and the placement of a xenograft as part of the regenerative procedure.

Figure 1: Initial condition: Clinical and radiographic examination. (A) Clinical photographs: A wide band of keratinized gingiva is observed, with a well- defined mucogingival line and frenula inserted below it. Tooth #12 shows buccal displacement and malposition, corresponding to a Class II canine relationship. A maladapted fixed metal-ceramic crown is also evident; (B) Radiographically: In tooth #21, a radiolucent periapical area is observed, along with an intraradicular radiopaque area consistent with previous endodontic treatment and the presence of a metallic post. Periodontal ligament space widening and bone loss reaching the apical third are also visible; (C) Initial periodontal charting shows the presence of periodontal pockets ≥4 mm at multiple sites, confirming active periodontal disease, with a 7 mm pocket detected in the affected tooth.

Figure 2: Tomographic evaluation.

In the coronal, sagittal and axial tomographic sections, as well as in the volumetric reconstruction, a hypodense area is identified in the periapical region of tooth #12, consistent with a bone lesion. The lesion presents morphological characteristics of a three-wall intrabony defect.

Surgical Procedure

Asepsis and antisepsis of the operative field were performed using a 0.12% chlorhexidine mouthwash and topical application of povidone-iodine. A sterile field was then established and local anesthesia was administered via infiltrative technique using 2% lidocaine with 1:100,000 epinephrine, targeting the anterior superior alveolar and nasopalatine nerves. Intrasulcular incisions were made, extending one tooth mesially and distally from the area of interest, using a 15C scalpel blade mounted on a No. 3 handle (Hu-Friedy®) (Fig. 3). Releasing incisions were made mesially and distally, encompassing one additional tooth on each end (Fig. 3B). A full-thickness flap was elevated, exposing 3 mm of apical bone with the aid of P20 and Buser periosteal elevators (Hu-Friedy®) (Fig. 3). All granulomatous tissue was removed using periodontal curettes (Hu-Friedy®) and an ultrasonic scaler (DTE®), followed by root planing and scaling of the involved dental surfaces (Fig. 3). The guided tissue regeneration membrane was trimmed using a pre-cut template, ensuring a 2 mm extension beyond the defect in the mesial, distal and apical directions (Evolution® membrane, OsteoBiol®, 30×30 mm). The bone graft (xenograft, Nukbone®, 0.5 g) was then placed (Fig. 4) and the membrane was positioned and stabilized with periosteal sutures (Vicryl 5-0, Ethicon®) using a sling technique, placing the membrane coronally at the level of the Cementoenamel Junction (CEJ) (Fig. 4). The flap was coronally advanced 2 mm beyond the CEJ without tension. Sutures were placed coronal to the CEJ and in the releasing incisions using single interrupted sutures (Vicryl 5-0). The patient was instructed to avoid mechanical cleaning for 3 to 4 weeks and was advised to use chlorhexidine rinse during the healing period (Fig. 4).

Figure 3: (A) Intrasulcular incisions; (B) Releasing incisions; (C) Flap elevation using periosteal elevators; (D) Full-thickness flap reflection; (E) Removal of granulomatous tissue on both buccal and palatal aspects.

Figure 4: (A) Placement of the bone graft viewed from palatal and buccal aspects; (B) Adaptation and apposition of the collagen membrane; (C) Suturing of the membrane to the periosteum; (D) Flap repositioning and suturing showing membrane exposure due to poor soft tissue adaptation.

Maintenance/Follow-Up

At the 5-day postoperative follow-up visit, generalized edema and erythema were observed in the anterior region, along with biofilm accumulation. In response to these findings, the area was irrigated with saline solution, oral hygiene instructions were reinforced and postoperative care recommendations were reiterated (Fig. 4,5). At 15 days, a reduction in the inflammatory process was noted; however, erythema persisted in the treated area and more pronounced buccal recession was observed in tooth 12. During this visit, the sutures were removed (Fig. 6). Additionally, a referral to the prosthodontics department was made for removal of the metal-ceramic crown and placement of an acrylic provisional restoration (Fig. 7), as well as fabrication of a splint and coordination with the endodontist for retreatment of tooth 12 (Fig. 6). At the 3-month clinical and radiographic evaluation, proper healing was observed, with absence of inflammatory signs, reduced probing depth and no suppuration (Fig. 6). At the 6-month follow-up, the periapical radiograph showed evident bone formation at the defect site, accompanied by decreased tooth mobility and improved functional stability of the involved tooth (Fig. 6). Finally, at the 1-year follow-up, significant clinical and radiographic improvements were noted: bone gain apically extending to the middle third of the root, reduced probing depth, decreased mobility and slight widening of the periodontal ligament space. Based on these findings, the patient continued with a regular periodontal maintenance protocol (Fig. 7).

Figure 5: Five-day post-surgical re-evaluation. Slight swelling and color change are observed, as well as migration of the soft tissue from tooth 12 toward the apical area.

Figure 5: Five-day post-surgical re-evaluation. Slight swelling and color change are observed, as well as migration of the soft tissue from tooth 12 toward the apical area.

Figure 7: Follow-up. (A,B) Provisional crown adaptation; C) Evaluation of the splint to provide stability to the tooth; D) Radiograph showing good adaptation of the bone substitute; E) Periodontogram showing a decrease in periodontal pocket depth and dental mobility after 1 year of follow- up.

Clinical Outcome

Endoperiodontal lesions represent a significant clinical challenge as they simultaneously affect both pulpal and periodontal tissues. They are fundamental in dental practice and their proper management is essential. An accurate diagnosis is the cornerstone for successful and lasting treatment, as it allows for the establishment of an individualized and appropriate therapeutic plan. It is important to emphasize that these lesions often require a staged approach, first addressing the endodontic component and subsequently the periodontal one. Failure to respect this sequence often leads to treatment failure. Therefore, the primary goal should always be to preserve the tooth and restore its long-term function and stability. In the presented case, satisfactory bone and tissue regeneration was achieved, with evident clinical and radiographic improvement at six months. Increases in bone levels, reduction in periodontal probing depth and decreased tooth mobility were observed. These results support the use of regenerative techniques in cases with a guarded prognosis, provided that three key pillars are met: accurate diagnosis, rigorous biofilm control and appropriate surgical technique. Among the advantages of this type of therapy are its biocompatibility, ease of handling and the elimination of a second surgery for membrane removal. However, it also presents limitations, such as the need for strict oral hygiene by the patient, precise surgical execution and proper preoperative planning. Long-term follow-up is recommended to evaluate the stability of the obtained results and ensure the durability of the treated tooth.

Discussion

Endoperiodontal defects represent a significant clinical challenge due to their multifactorial etiology and the anatomical communication between the dental pulp and periodontium, which requires a comprehensive therapeutic approach. In the present case, a type V endoperiodontal lesion in a maxillary lateral incisor with a crater-type defect was treated using Guided Tissue Regeneration (GTR) with xenograft and collagen membrane, achieving satisfactory clinical and radiographic outcomes after one year of follow-up. The literature supports the combined use of regenerative materials in complex periodontal defects. Stoecklin-Wasmer, et al., conducted a systematic review showing that GTR with collagen membranes, with or without bone grafts, results in significant clinical attachment gain and probing depth reduction in intraosseous defects compared to debridement alone [12]. These findings support the therapeutic approach applied in this case. Velásquez-Plata, highlights that in one- or two-wall defects, as well as crater-type defects like the one reported here, the use of bone grafts and membranes is a primary option to achieve predictable bone regeneration [13]. Regarding biomaterial exposure, several studies indicate that exposures less than 20% do not negatively affect clinical outcomes if adequate infection control is maintained. Wessing in a systematic review and meta-analysis on guided bone regeneration with collagen membranes and particulate graft materials, concluded that membrane exposure does not necessarily compromise clinical results if managed with proper hygiene and postoperative monitoring. This evidence aligns with the evolution observed in this case, where satisfactory regeneration occurred despite controlled partial membrane exposure [14]. Similarly, Weltman, et al., reported that resorbable membranes did not compromise attachment gain or bone regeneration, even in the presence of partial exposure [15]. Bovine bone xenografts, like the one used in this case, provide an ideal osteoconductive matrix, promoting bone regeneration and stabilization of the blood clot [16,17]. Their combination with membranes significantly improves clinical outcomes compared to conventional surgical techniques such as full-thickness flap or curettage [18,19]. Collagen membranes play a key role in GTR by acting as physical barriers that prevent epithelial migration into the bony defect, thus favoring the growth of osteoprogenitor cells [20]. Additionally, their chemoattractive, hemostatic properties and low immunogenicity contribute to favorable tissue integration without eliciting foreign body reactions [21,22]. Successful periodontal regeneration depends on respecting fundamental biological principles: formation of a stable blood clot, protection of the surgical site by soft tissue and prevention of undesired epithelialization [7,23,24]. These principles were strictly followed during the surgical management of this case. Regarding endodontic therapy De Sanctis and Goracci, state that preventive endodontic treatment is not necessary in teeth with vital pulp and no symptoms, even if they are indicated for regenerative surgery [24]. In this case, since the tooth had already undergone endodontic treatment, retreatment was chosen as part of the comprehensive approach. The results obtained are consistent with previous studies reporting significant bone regeneration and clinical improvement in periodontal defects treated with xenografts and membranes, even in combined type III lesions according to Simb on’s classification [16,25].

Conclusion

In the present case, despite partial membrane exposure during the postoperative period, meticulous oral biofilm control by both patient and clinician was paramount in preventing infectious complications. Careful consideration of these factors during treatment planning is essential to optimize clinical outcomes. Moreover, an interdisciplinary approach involving periodontists, endodontists and other dental specialists is crucial. Collaborative management allows comprehensive case assessment, informed decision-making and precise therapeutic execution, ultimately improving success rates and ensuring long-term preservation of the compromised dentition. This rigorous oral hygiene facilitated preservation of the surgical site and successful regeneration of bone and periodontal tissues. It is important to recognize that the success of such treatments is influenced by multiple factors, including the patient’s systemic and local conditions, the morphological characteristics of the defect and technical variables related to the surgical procedure.

Conflict of Interest

The authors declare that they have no conflicts of interest with the contents of the article. 

Funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

Author Contributions

All authors contributed equally for this paper.

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