Management of fenestration using bone allograft in conjunction with platelet-rich fibrin.

Fenestration and dehiscence are said to be anatomical variations of cortical bone and not true pathological entities. They represent window-like defects covered by periosteum and overlying gingiva with or without the intact marginal bone. The etiology of such defects is still unclear, though many hypotheses such as occlusal traumatism, trauma, and variation in root bone angulation have been put forward. Diagnosis of such defects is challenging clinically, and they cannot be appreciated in conventional radiographs. In many instances, they are accidentally discovered during periodontal and oral surgical procedures. These defects, if not treated, can affect prognosis and complicate healing of the affected teeth. Treatment of such cortical bony defects is challenging and involves the use of potential regenerative materials to aid in regeneration. This case report describes the successful management of such a defect, discovered through exploratory flap approach, using PRF in conjunction with bone allograft.

INTRODUCTION

Height and density of the alveolar bone are normally maintained by equilibrium, regulated by local and systemic influences between bone formation and bone resorption. When resorption exceeds formation, bone height, density, or both are reduced.

The position of the bony margin mimics the contour of the cementoenamel junction. This bony scalloping is related to tooth and root form, as well as tooth position within the alveolus. Teeth with prominent roots or those displaced facially or lingually are said to be more prone to exhibit defects such as fenestration or dehiscence, due to thin buccal or lingual plate. Fenestrations are isolated areas, in which the root is denuded of the bone, and the root surface is covered only by periosteum and overlying gingiva, with intact marginal bone, whereas dehiscence is similar to fenestration but with the involvement of marginal bone. Although they are considered nonpathological conditions, and as variations within the range of periodontal normalcy, their undiagnosed or unexpected presence may complicate periodontal surgical procedures. Horizontal and vertical fracture of the root are said to be predisposing factors.[1]

Management of such defects involves exposure of the defect and use of regenerative materials as bone grafts and different types of membranes. One such membrane is platelet-rich fibrin (PRF), a natural reservoir for growth factors, with a strong fibrin matrix useful in tissue regeneration. PRF was first developed by Choukran et al. in France. PRF affects cell biology activities on both the genetic and cellular levels. It is used as a scaffold for breeding periosteal cells and bone regeneration in situations such as sinus lift procedures, treatment of osseous defects, and coverage of denuded roots.[12]

The following case reports the discovery of fenestration defects through exploratory flap approach and their management using bone graft and PRF membrane.

CASE REPORT

A 27-year-old male patient was referred to Department of Periodontics with the complaint of developing hollowness in the left cheek region which was causing esthetic concern to the patient. The patient also suggested to check intraorally and revealed that he has been observing this change since 2 months. There was no significant past medical history or dental history related to it.

Extraoral findings revealed a hollow oval-shaped depression of about 1 inch × 0.8 inch in dimension in the left cheek region, adjacent to nasolabial fold below the malar region [Figure 1]. On palpation, the buccal mucosa appeared normal. Intraoral clinical examination revealed marked concavity between 24 and 25 region. Roots appeared more prominent and tissue biotype was thin [Figure 2]. Intraoral periapical radiograph was advised which revealed marked reduction in radio-opacity between 24 and 25 in comparison with adjacent teeth region [Figure 3]. The teeth appeared vital on testing. Treatment was planned that consisted of exploring the defect with open flap surgery. The bone sounding was another option to be considered to evaluate the defect, but since the bone height appeared to be normal, clinically and radiographically, the surgical approach appeared to be more accurate for the direct visualization of the defect. After the blood investigations were found to be within normal limits, that is, a complete blood count was carried out to rule out the general health status, a full-thickness mucoperiosteal flap was elevated, which included a crevicular incision clubbed with two vertical incisions to delineate the area of interest [Figure 4]. Flap reflection revealed exposure of extremely thin bone on 24 and two fenestration defects on the root of 25. Roots appeared more prominent with marked concavity between them [Figure 5]. However adequate bone was found adjacent to 23 and 26 on either side. Two corticotomy sites of 0.5-mm diameter were prepared adjacent to the root prominence in the bone for vascularization. In the concavity and over the defect, bone allograft consisting of demineralized freezed dried bone allograft of particle size ranging from 500 to 1000 μ (DFDBA) (Tissue Bank of Tata Memorial Hospital, Mumbai) was placed [Figure 6] and covered with PRF membrane [Figure 7]. The flap was sutured using 4-0 black braided silk. Periodontal dressing was placed over the flap (Coe-Pack, GC America). The patient was discharged with prescription of antibiotics and anti-inflammatory medication (amoxicillin 500 mg thrice a day for 5 days and diclofenac sodium twice a day for 3 days), for better predictability of results and less postoperative infection. The patient was instructed to use 0.2% chlorhexidine mouthwash (Hexidine, ICPA Health products) for 2 weeks. The patient was recalled after 8 days and sutures were removed. The healing was uneventful. The patient was followed up for 3, 6, and 9 months [Figure 8]. At the end of 9 months, a postoperative radiograph was advised which revealed marked radio-opacity between 24 and 25 [Figure 9]. The patient was satisfied with the outcome of the treatment. Extraoral view of depression near left modiolus treated by correction of fenestration in relation to 24 and 25 [Figure 10].

Figure 1

Extraoral view showing slight hollowness in left cheek region

Figure 2

Noticeable concavity between 24 and 25

Figure 3

Preoperative view of intraoral periapical radiograph between 24 and 25

Figure 4

Placement of two vertical and crevicular incisions

Figure 5

Reflection of full thickness flap reveals areas of fenestrations and extremely thin bone over root of 24

Figure 6

Placement of allograft in the vertical depression between 24 and 25

Figure 7

Placement of platelet-rich fibrin membrane

Figure 8

Postoperative clinical view after 6 months

Figure 9

Postoperative view of intraoral periapical radiograph between 24 and 25

Figure 10

Extraoral view showing obliteration of the fenestration defect after 9 months

DISCUSSION

The alveolar bone architecture may vary from patient-to-patient in terms of thickness, contour, and configuration. The cause of differences depends on the morphology of alveolar process and teeth. The bony contour conforms to the prominence of roots with intervening vertical depressions that taper toward the margin.[3]

Fenestration and dehiscence occur in both maxilla and mandible with overall prevalence rates ranging from 0.99%–0.53.62% to 0.23%–69.575%, respectively.[1]

According to a study by Nimigean et al., the prevalence and distribution rate of dehiscence and fenestration was 53.623% and 69.565% in dried skulls. The teeth most often affected by fenestration was maxillary first molar (42.628%) followed by mandibular first molar (16.026%) and maxillary first premolar (14.423%), and by dehiscence was mandibular canine (40.645%) followed by mandibular first premolar (18.664%) and maxillary canine (17.419%). Most of such defects show the involvement of buccal alveolar plate compared with palatal.[3] Similar findings were reported by Agrawal.[4]

The etiology of fenestration and dehiscence are yet to be clarified and substantiated, though suggested etiologic factors include age-related changes, positional relationship between teeth and alveolar bone, occlusal dysfunction, trauma, horizontal, and vertical root fracture.[145]

Studies have pointed out that a combination of prominent roots with thin alveolar bone plate to be a reason for the occurrence of dehiscence and fenestration, while other studies have suggested influence of occlusal forces. Stahl found attrition (indication of occlusal stress) present in all the teeth affected with fenestration and dehiscence, contradictory to findings of Edel, who found no relationship between the two. The authors concluded that variation in teeth positioning in the arch (buccoversion, linguoversion, supereruption, and intrusion) appear to be the major determinant factor of cortical plate thickness and contour.[3] In the present case, no occlusal faceting or any other occlusal discrepancy was noted, except for thin alveolar housing over the roots of 24 and 25.

Treatment of fenestration involves covering the defect with bone graft and a membrane to aid in the regeneration of lost periodontal tissues. Hence, in the present case report, bone allograft DFDBA was used due to its osteoinductive property. PRF was used as it would act as a protective barrier to cover the defect was cost-effective and aids in regeneration and healing. PRF can also be used as a biomaterial as well as a healing concentrate with its assembly of cytokines, glycanic chains, and glycoproteins enmeshed in a fibrin network.[6]

Limitations of the present case report were nonassessment of true regeneration with surgical intervention which could not be carried out due to the ethical reasons. Tomodensitometric analysis would be of value in assessing defects on buccal and lingual aspects which cannot be discerned on radiographs. Tomodensitometric analysis is of utmost importance, especially during oral implantological procedures through flapless approaches which conceal them.

CONCLUSION

Patient's complaint of developing hollowness shows the esthetic concern and their need to restore the face value, led to investigate the problem further. Dehiscence and fenestration are accidentally discovered entities. Their diagnosis becomes challenging. Once diagnosed their management becomes easy using potential regenerative materials. Hence, careful assessment of such alveolar defects through tomodensitometric analysis is required before carrying out further treatment.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.