A Window to Treating Apical Fenestration: Surgical Management of Non-Healing Symptomatic Periapical Lesion

Introduction

The American Association of Endodontics describes fenestration as ‘a window like opening or a defect in the alveolar bone mostly exposing a portion of root’.¹ This phenomenon of fenestration can be physiological or pathological. When the apical region of the tooth is involved, it is known as an apical fenestration. A fenestration differs from a dehiscence. The marginal bone is always compromised in dehiscence, although both can involve the root apex.² Mucosal fenestration is a rare clinical pathology in which a part of the root of the affected tooth is exposed in the oral cavity. It can be a combined perforation of the overlying bone and mucosa also.³

Apical fenestrations combined with endodontic infections such as apical periodontitis could be due to inflammation of the periradicular tissues and resorption of the bony cortical plate.^4,5 When both the entities occur synchronously, prompt diagnosis and management are the key to successful endodontic therapy.⁶ It is possible that apical fenestration might not always be present with mucosal fenestrations.^7,8 Pus drainage and plaque accumulation in the collar along with inflammation can be present if there is a mucosal fenestration.^9,10

Signs and symptoms of patients with apical fenestration and endodontic infection occurring together include tenderness on percussion, pain on mastication, persistent abscess and evident gingival defects.^6,11,12 Patients sometimes can also be asymptomatic. Persistent apical periodontitis even after a root canal treatment can be misdiagnosed as a failed root canal treatment. Re-Root canal treatment for the same will also show the same radiographic finding. Repeated non-surgical root canal treatment will not relieve the pain in the presence of apical fenestration and may lead to apical root fracture.¹³ Due to this non constant clinical presentation of the latter, diagnosis is challenging with a 2-D intra oral periapical radiograph. Additional investigations such as CBCT (Cone Beam Computer Tomography) might also be needed for diagnosis.¹⁴

To restore and establish harmony between the root apex and overlying bone, non-surgical root canal treatment followed by apical root resection is needed.¹⁵ In cases with mucosal fenestration, surgical approaches like primary closure, guided tissue regeneration and mucosal grafts are advised.¹⁶

This present clinical case describes a rare situation of apical fenestration developed in the root apex of maxillary left first premolar that presented with previously treated root canal with sinus opening in the apical region. Interdisciplinary management by conventional endodontic treatment in combination with periapical surgery and bone grafting was done in order to restore the harmony of the periapical tissues along with successful periapical healing. This report also highlights the importance of accurate diagnosis and comprehensive treatment plan to restore the teeth with this complex endo-perio problem.

Case Presentation

A 35-year-old male patient presented in November 2021 to the clinic with a chief complaint of pain in upper left back tooth region for past one month. Routine intraoral clinical examination revealed previously treated left maxillary first premolar with sinus opening (Figure 1). On palpation, buccal mucosa concavity was present which was not prominent. The tooth was subjected to cold sensibility test and presented with no response compared to contralateral teeth.

Radiographic examination

Intra oral periapical radiograph revealed obturated canals with periapical radiolucency. After the removal of gutta-percha, a CBCT was advised for that region. CBCT revealed diffuse radiolucency in the periapical region of left maxillary first premolar (24) along with thinning and breach of buccal cortical plate which confirmed fenestration (Figure 2).

Treatment

A comprehensive treatment plan was made:

1) Complete root canal treatment in 24

2) Root end surgery along with curettage and bone graft placement

Root canals were prepared till #25-6% in both buccal and palatal canals and were obturated with an epoxy resin based sealer. Full thickness mucoperiosteal flaps were raised from mesial surface of canine region till distal surface of second premolar under local anaesthesia (2% lignocaine with epinephrine). Vertical tissue incisions were made using laser along with sulcular incision (Figure 3). After elevation of full thickness flap, fenestration defect was exposed (Figure 4). Apicectomy was performed in relation to both the roots. Complete curettage was done and once the complete curettage was confirmed, bone graft was placed (PERIOGLAS, NovaBone, LLC) along the defect area (Figure 5). Flaps were then placed in position for few minutes with wet saline gauze and sutured using 3-0 braided silk suture (Figure 6). Patient was prescribed Amoxicillin with clavulanic acid 625 mg thrice daily for five days and Diclofenac sodium twice daily for three days for better predictability of results and control of post-operative infection. Patient was recalled after a week for suture removal and the healing was uneventful. The patient was followed up for six months and was satisfied with the outcome of the treatment.

Discussion

Statistical data report states that incidence of apical fenestrations can occur in 9% of cases.⁸ The global prevalence of this is higher in maxilla than in mandible and the most frequently affected root is the mesiobuccal root of the maxillary first molar, followed by the maxillary first premolars (10.46%), maxillary lateral incisors (7.80%) and finally maxillary canines (7.58%).¹⁶ Elements such as age and tooth malposition can be predisposing factors for fenestration defects. Strong occlusal forces may also be an aggravating factor, as are certain anatomical configurations of the teeth that facilitate the contact of the apex with the cortical bone.¹¹

Although apical fenestrations are usually symptom-free if left alone, these might lead to pain when a root canal treatment is done on a tooth that already has this type of bone defect. This was first described by Spasser and Wendt.¹¹ The bony defect itself will not be causing any pain, because the teeth which are not endodontically treated and not covered by bone present as asymptomatic. However, once the endodontic treatment is completed, the patient might start experiencing pain. This is because, when there is a slight extrusion of excess filling material beyond the apex, any slight movement of the tooth will cause irritation to the mucosa over the apex. The tooth becomes sensitive, and pain is perceived primarily during masticatory movements or palpation. These symptoms can get aggravated when the patient rubs the mucosal area with the fingers.¹¹

The reported cases of fenestration are frequently related to inflammatory processes associated with periodontal disease or trauma, while in the present clinical case, there was no history of previous trauma. Therefore, variations in individual periodontal architecture, including a thin buccal plate, along with a thin periodontal biotype can also be considered as predisposing factors.

Apical fenestrations are rare entities in clinical practice and there is very little evidence in the literature regarding the therapeutic management of these conditions. In the present case, an endodontic treatment was initially performed to ensure complete disinfection and sealing of the root canal. Root end surgery, which included surgical resection of the apex was performed to clear off any ramifications. The main objective of root resection in the present case was to maintain the root within the limits of the cortical bone so that any anatomical ramifications are prevented and also to provide an adequate anatomical configuration to prevent future apical exposure.

Conclusion

Apical fenestrations if present along with endodontic pathology can result in persistent pain and tenderness on percussion. Routine radiographic investigations might not be of much use. CBCT evaluation of the same can facilitate a prompt diagnosis and treatment accordingly. Routine endodontic treatment along with surgical resection of the apical portion of the tooth and graft for the bony defect can be set as a standard treatment of choice.

Conflict of interest

None

Acknowledgement

The patient signed written consent form to allow his case to be published.