An innovative approach in the management of palatogingival groove using Biodentine™ and platelet-rich fibrin membrane.

Palatogingival groove is an anatomical malformation that often causes severe periodontal defects. Treatments of such an anomaly present a clinical challenge to the operator. Careful endodontic and periodontal procedures may restore the form and function. In the present case; root canal therapy, apicectomy, and sealing of the groove with Biodentine™ were done. Bone graft was placed followed by platelet-rich fibrin (PRF) membrane. This treatment modality resulted in gain in attachment, reduction in pocket depth, and deposition of bone in the osseous defect. A 24 month follow-up is included.

INTRODUCTION

The region of maxillary lateral incisor is an area of embryological importance. A great number of major and minor malformations occur in this area; for instance gemination, fusion, cysts, dens in dente, peg-shaped laterals, talon cusps, supernumerary roots, and palatogingival groove (PGG). PGG is defined as “a developmental groove in a root that, when present, is usually found on the lingual aspect of maxillary incisor teeth”.[1] Goon et al., suggested a classification, which represents two types of PGG, simple and complex.[2] The simple PGG does not communicate with the pulp and represents a partial unfolding of Hertwig's epithelial root sheath (HERS), while complex PGG communicate directly with the pulp and groove that extend the length of the root. In rare cases, the groove may lead to minor accessory root, which may contain a root canal.[3]

There are conflicting speculations regarding the etiology of PGG. Some authors proposed that this defect is a mild form of dens invaginatus,[4] whereas others believe that it is the incomplete attempt of a tooth to form another root.[5] A genetic mechanism[6] and racial link[7] has also been proposed. The incidence of radicular groove is reported to be between 2.8 and 18%.[7]

The negative effect of PGG is related to their plaque accumulating effect. The groove may facilitate plaque growth by providing surface areas sheltered from cleaning efforts as well as from host defense mechanisms. In cases where the pulp has also become necrotic, the tooth requires endodontic treatment in addition to periodontal therapy. However, it is important to note that it is the ability to adequately treat the periodontal defect that ultimately determines the prognosis of these teeth. Suggested treatment modalities were curettage of the affected tissues, elimination of the groove by grinding (saucerization), or by sealing with a variety of filling materials. If the groove extends beyond the middle-third of the root apex, surgical procedures are required, including use of barriers and intraosseous graft to correct the defect.[8]

Presented is a case of a PGG in a maxillary incisor treated successfully with a combined endodontic, biodentin, and platelet-rich fibrin (PRF) membrane therapy. The rationale for this treatment modality is also discussed.

CASE REPORT

A 24-year-old male patient who had a complaint of dull and intermittent pain at the palatal side of the left maxillary lateral incisor came to Department of Endodontics. During the clinical examination, the left maxillary lateral incisor (#10) had an intact crown without caries or fracture, with negative vitality testing and a positive response to percussion [Figure 1]. The tooth was grade 2 mobile. Periodontal probing disclosed a periodontal pocket (9 mm) at the mesiopalatal line angle of the tooth and concomitantly, a PGG which extended into the gingival sulcus [Figure 2]. Facially the gingival sulcus had 8 mm probing depth. Oral hygiene was satisfactory. An occlusal radiograph revealed a large periapical lesion with a bony defect extending beyond the apical third of the root [Figure 3]. Gutta-percha tracing into the sinus tract and periodontal pocket revealed a communication with the periapical area. Based on the tests and the radiographic findings, the diagnosis was necrotic pulp, suppurative periradicular periodontitis and localized periodontitis secondary to the palatal groove on tooth #10.

Figure 1

Preoperative clinical

Figure 2

Preoperative clinical palatal view

Figure 3

Preoperative occlusal view

In phase one therapy, oral prophylaxis was performed. Stabilization of the tooth was done with stainless steel wire and composite resin. Endodontic access was performed after placing a rubber dam and disinfecting the area with 2% chlorhexidine digluconate (Calypso, Septodont, India). Working length was determined by using electronic apex locator Root ZX (J. Morita Mfg. Corporation, Kyoto, Japan) and file in-radiograph with 15 no. K-files. The root canal was cleaned and shaped by rotary Ni-Ti ProTaper System along with Glyde (Dentsply Maillefer Company, USA) using crown down technique. The root canal was copiously irrigated with 2.5% sodium hypochlorite (Novo Dental Product, India). Access cavity was temporized with calcium hydroxide and TERM. Patient was recalled after 1 week; the tooth was asymptomatic. Root canal was irrigated again with normal saline and dried using paper points. Before obturation, master points were seated to test their suitability to canal and radiograph was taken. The canal was obturated with selected master gutta-percha cone (variable taper]) and AH-Plus sealer (Dentsply Maillefer Company, USA). The coronal gutta-percha cones were sheared off using heated instrument, and vertical compaction was done using the heated pluggers at the canal orifices. During the periodontal phase of the therapy, complete extraoral and intraoral mouth disinfection was done with betadine and local anesthesia was administered (xylocaine 2% with epinephrine 1:80,000). A surgical flap was raised from the palatal aspect and labial aspect, and the PGG was isolated to its most apical extent [Figure 4]. Thorough scaling and root planning was performed over the groove to remove the bacteria that might have colonized there. The diseased granulation tissue was curetted out with Gracey curette number 1/2 and 5/6; (Hu-Friedy Manufacturing Co, Chicago, IL) to leave the soft tissue more conducive to regeneration. A chemical conditioning of the groove was performed and Biodentine™ (Septodont, St. Maur-des-Fossés, France) was applied into the defect [Figure 5]. With the help of an air-driven surgical handpiece (Impact Air, Palisade Dental), the apical root end was resected and sealed with Biodentine™ (Septodont, St. Maur-des-Fossés, France) [Figure 6]. The area was kept isolated of blood and tissue fluids during the setting of the cement by using local hemostatic gelatin sponge (Pfizer Inc, New York, NY).

Figure 4

Palatogingival groove exposed after elevating a full thickness flap

Figure 5

Sealing of the PGG with biodentin

Figure 6

Removal of the granulation tissue and debriding the defect

Preparation of PRF membrane

A 12 ml sample of whole blood was drawn intravenously from the patient's right antecubital vein and centrifuged (REMI Model R-8c with 12 × 15 ml swing out head) under 3,000 rpm for 10 min to obtain the PRF which was jelly-like in consistency. PRF clot started to release its serum (PRF-clot exudates) and was ready for compression into the membrane. The bony defect was filled with freeze-dried bone allograft (LifeNet, Virginia Beach, VA) [Figure 7]. Without delay autologous PRF membrane was placed [Figure 8] and the flaps were secured with 4-0 polyglactin 910 sutures (Vicryl, Ethicon, Inc., Piscataway, NJ).

Figure 7

Placement of bone graft

Figure 8

Placement of platelet-rich fibrin membrane

Following surgery, the patient was placed on doxycycline 100 mg, with instructions to take two capsules immediately, then one capsule every day for 14 days. In addition, a 0.12% chlorhexidine gluconate rinse was prescribed and ibuprofen was given for discomfort. The patient was asymptomatic postoperatively and sutures were removed after 7 days. The patient was recalled for 6 months for a period of 2 years. There was both a clinical and radiographic improvement. Clinically, there was a reduction in the pocket depth of 5 mm in 6 months and patient is asymptomatic with a 3 mm non-bleeding sulcus at the end of 24 months. There was a significant reduction in radiolucency radiographically [Figure 9].

Figure 9

Twenty-four month follow-up

DISCUSSION

PGG is mostly found in maxillary lateral incisors and have been implicated as an initiating factor in localized gingivitis and periodontitis. Focal loss of periodontal attachment associated with these grooves, some of which may extend to the apical third of the root could result in a hopeless prognosis for tooth retention. In cases where the pulp has also become necrotic, the tooth requires endodontic treatment in addition to periodontal therapy. The aim of our treatment was to eliminate the groove and to regenerate the attachment apparatus.

Elimination of groove

Many materials have been used for eliminating the groove like composites, mineral trioxide aggregate (MTA), glass ionomer, and emdogain. A tricalcium-based cement called Biodentine™ was used in the present case. Biodentine™ is recommended for use as both an endodontic repair material and a dentin substitute under resin composite restorations. It contains tricalcium silicate, dicalcium silicate, calcium carbonate and oxide, iron oxide, and zirconium oxide as its powder components; and calcium chloride and a water-soluble polymer as its liquid components. The two main benefits of Biodentine™ over other products are the reduced setting time (a few minutes compared with several hours for MTA) and better mechanical properties. Moreover, its sealing ability, when in contact with dentin, has been confirmed in vitro with a very low silver nitrate penetration.[9] The use of tricalcium silicate avoids the presence of trace elements which are inadvertently incorporated in MTA from the raw materials and the secondary fuels used during manufacture.[10] Tricalcium silicate-based cements do not leach any contaminants, thus are considered safer for use as root-end filling materials and for sealing the groove.[11]

Regenerate the attachment apparatus

In Choukroun's PRF (platelet-rich fibrin) blood is collected without any anticoagulant and immediately centrifuged. A natural coagulation process then occurs and allows for the easy collection of a leukocyte- and platelet-rich fibrin (L-PRF) clot, without the need for any biochemical modification of the blood, that is, no anticoagulants. This open-access technique is the most simple and also the least expensive protocol developed so far. PRF is a complex biomaterial with a specific biology. It is organized as a dense fibrin scaffold, with a high number of leukocytes concentrated in one part of the clot, with a specific slow release of growth factors (GFs) (such as transforming growth factor type beta 1 (TGF-β1), platelet-derived growth factor (PDGF)-AB, vascular endothelium growth factor (VEGF)) and glycoproteins (such as thrombospondin-1) during at least 7 days.[12] Leukocytes seem to have strong influence on GF release, immune regulation, antiinfectious activities, and matrix remodeling during healing.

Several materials were utilized to optimize regeneration of the lost periodontal and osseous structures. Freeze-dried bone allograft was chosen to fill the osseous defect because of its osteoconductive nature, and its ability to be converted into bone more rapidly than demineralized freeze-dried bone allograft. The intended role of the PRF membrane in our case report was to contain the hydroxyapatite in the bony defect in the early phase of wound healing. In our case report, two layers of PRF membranes were placed over the defect because; firstly, this membrane is a thin fibrin scaffold that might undergo quick resorption; secondly, PRF membranes are inhomogeneous, since leukocytes and platelet aggregates are concentrated within one end of the membrane. Therefore, the use of two membrane layers with membranes in opposite sense, allows to have the same components (platelets, leukocytes, fibronectin, and vitronectin) on the whole surgical surface.[13] The membrane was slightly hanged over the edge of the wound as it controls the migration of the different tissue families on the wounded site, thereby directing the organization of the wound. In PRF, the high concentrations of collected platelets allow for the slow release of GFs from the platelet granules.[14] These play a role in replacing lost tissue, resurfacing of the wound, and restoring vascular integrity. Compared to other platelet concentrates, L-PRF releases these factors at a sustained rate over a longer period, thereby optimizing wound healing.[15] Recently, L-PRF has also been shown to stimulate the growth of osteoblasts and periodontal ligament cells, both of which are significant for the regeneration of periodontal defects.[15]

This case report involved a maxillary lateral incisor with a deep palatal groove and associated periodontal and pulpal involvement. As a result of the extensive nature of this groove on the lingual surface, tooth #10 had a complicated root canal anatomy and severe localized periodontal disease requiring a combined endodontic-periodontic treatment approach. The PRF membrane acts by releasing high-concentration GFs to the wound site, thereby stimulating healing and new bone formation. The use of PRF membrane is a simple method that requires minimal cost and reduces the need for specialized grafting material. Because it is a completely autologous product, the risk of disease transmission and graft rejection is negated. Biodentine™ that has high mechanical properties with excellent biocompatibility, as well as a bioactive behavior was used to seal the groove.