Successful Surgical Management of Palatogingival Groove Using Platelet-rich Fibrin and Guided Tissue Regeneration: A Novel Approach.

Palatogingival groove also known as radicularlingual groove is a developmental anomaly involving the lingual surface of the maxillary incisors. They are inconspicuous, funnel-shaped, extend for varying distances on root surface and occur due to infolding of the hertwigs epithelial root sheath. This encourages adherence of microorganisms and plaque to levels significant for pathological changes resulting in endodontic and periodontal lesions. The variations in anatomy of the tooth as a cause of pulp necrosis in teeth of anterior maxillary segment should be considered by the clinician when other etiological factors are ruled out. Recognition of palatogingival groove is critical, especially because of its diagnostic complexity and the problems that may arise if it is not properly interpreted and treated. Regeneration is a new emerging approach in endodontics. Choukroun et al. were among the pioneers for using platelet-rich fibrin (PRF) to improve bone healing. PRF is rich in platelet cytokines and growth factors. Numerous techniques have been used to eliminate or seal the groove and regenerate endodontic and periodontal tissues. In this case report of two cases, a novel combination therapy involving ultrasonics, blend of PRF with bone graft, guided tissue regeneration membrane was used in the treatment of a palatogingival groove with an endoperio lesion to ensure arrest of disease progression and promote regeneration. The groove was cleaned and prepared ultrasonically and sealed with a bioactive dentin substitute.

INTRODUCTION

Failure of endodontic therapy has been reported in the upper incisors due to a unrecognized palatogingival groove first reported by Lee et al.[12] This is also known as radicularlingual groove, distolingual groove, radicular anomaly, and syndesmocoronoradicular tooth. Recognition of the palatogingival groove is very important, especially because of its complexity and the problems that may arise if it is not properly diagnosed and treated.[3] Its prevalence is 2.8%–8.5% and is most commonly seen in the maxillary lateral incisors and less frequently in the central incisors.[45] An incidence of 18% has been reported in Chinese population.[6] It has been suggested that the groove presumably is an aborted attempt to represent an additional root.[7] Other mechanisms such as racial. Genetic and as a mild form of dens invaginatus have been proposed. Surgical procedures involving removal of granulation tissue, odontoplasty, scaling, root planing of the area with the groove, and endodontic therapy for the tooth involved has resulted in adequate periaical healing and effectively reduced the gingival probing depth.[8] Palatogingival grooves can cause pulpal and periodontal pathology, but they may be difficult to identify as an etiological factor.[9] Radicular grooves have been reported in maxillary incisors which were very deep and had a communication with the pulp chamber.[10] Accessory canal communications between the pulp chamber and the periodontium through the groove exist which necessitates adequate sealing of the groove.

The clinical advantages of combining regenerative procedures with platelet-rich fibrin (PRF) has been extensively investigated and results now support the use of PRF for periodontal and soft-tissue repair.[11] PRF is a second-generation natural fibrin-based biomaterial made from fresh blood from the patient by centrifuging without biochemical modifications, thereby attaining fibrin enriched by leukocytes, platelets, and growth factors.[12] Choukroun's PRF contains cytokines and cells are entrapped in a matrix, which is released after a short period and can serve as a resorbable membrane. The rationale behind the use of PRF membrane is that the platelet α granules are a reservoir of many growth factors that are known to play a definitive role in tissue repair.[13]

Guided tissue regeneration (GTR) involves placement of a barrier membrane around the periodontal defect to prevent fibroblast transgrowth into the wound space and epithelial down growth, thereby providing a space for true periodontal regeneration.[14] Periodontal ligament cells can promote new cementum, periodontal ligament, and bone formation. Periodontal ligament cells also can reestablish connective tissue attachment, when the contact between gingival epithelium and the root surface is prevented by use of a barrier membrane.[15]

CASE REPORTS

Case 1

A 24-year-old male reported with chief complaint of pain and bleeding gums in the upper anterior teeth for the past four months. He had intermittent dull pain with recurrent episodes which subsided on medication. Clinical examination revealed a notch at the junction of palatal marginal gingiva of the left upper lateral incisor (22) [Figure 1a]. The depth was 6 mm on probing (Williams probe) and grade I mobility was present. Radiographic examination revealed periodontitis [Figure 2a]. Electric pulp testing showed no response, was diagnosed as severe localized periodontitis and necrotic pulp secondary to palatal groove in 22 and endodontic therapy initiated.

Figure 1

(a) Preoperative. (b) Depth of groove. (c) Sealing with bioactive dentin substitute. (d) Platelet rich-fibrin, bone graft and guided tissue regeneration placement. (e) Postoperative. (f) Six months review

Figure 2

(a) Preoperative radiograph showing peri apical lesion. (b) Master cone. (c) One-year review showing the formation of new bone. (d) Immediate postobt uration radiograph

Endodontic therapy was initiated as first phase of the treatment under rubber dam isolation. The canals assessed and working length confirmed using apex locator (Root zx mini, Morita, Japan). The canal was shaped and cleaned with K-files (15–40) (Dentsply, Maillefer, Ballaigues, Switzerland) using crown-down technique. [Figure 2b] Irrigation was done using 3% sodium hypochlorite followed by 17% ethylenediaminetetraacetic acid (EDTA) for 1 min. Calcium hydroxide paste was packed using a lentulo into the canal and replaced every week for 3 weeks after removal of the old calcium hydroxide using ultrasonics. Triple antibiotic paste was also added along with calcium hydroxide at the third dressing change. Subsequently, after thorough irrigation with normal saline, the canal was dried with paper points and obturated with thermoplasticized gutta percha and AH plus (dentsply) sealer [Figure 2d].

Periodontal therapy was initiated as the second phase of treatment. Under local anesthesia, palatal sulcular incision given in relation to 21, 22, and 23, kirkland flap elevated to expose the root surface. Open flap debridement done where palatogingival groove was visible in distopalatal aspect of 22 [Figure 1b] through debridement with ultrasonic scaler was done and granulation tissue removed with gracey curettes number 1–2. The palatogingival groove was prepared using ultrasonic retroprep tips, irrigated with normal saline and sealed with bioactive dentin substitute (biodentine) and allowed for initial set for about 10 min during which the cement was hydrated with moist cotton gauze [Figure 1c]. The bone graft material (sybograft) and autologous PRF were mixed and placed in the bony defect, followed by GTR membrane [Figure 1d]. The flap was repositioned and stabilized with interrupted suture [Figure 1e]. Postoperatively, the patient was asymptomatic and suture removed on the 7th day. The patient was reviewed initially once in 2 weeks, and after 6 months, the postoperative radiograph showed satisfactory healing and reduction of pocket depth to 3 mm [Figures 2c and 1f].

Case 2

A female patient of 26 years came to our department with a complaint of recurrent episodes of dull pain associated with the left upper front tooth which aggravated early morning and relieved spontaneously within 30 min to 1 h. Clinical examination revealed a notch starting from central fossa in mesio palatal region in 21 [Figure 3a, e]. The groove was about 7 mm in depth with Grade II mobility. On radiographic examination, there was bone loss seen between 11 and 21 [Figure 4a]. Electric pulp testing shows no response indicating loss of vitality in 21. A diagnosis of severe localized periodontitis with necrotic pulp secondary to palatogingival groove on 21 was made and endodontic therapy scheduled.

Figure 3

(a) Palatogingival groove. (b) Sealing with bioactive dentin substitute. (c) Platelet rich fibrin, bone graft and guided tissue regeneration placement. (d) Postoperative. (e) Preoperative labial view. (f) Postoperative view 6 months

Figure 4

(a) Preoperative radiograph showing periapical lesion and lateral bone loss. (b) Master cone. (c) Immediate postobturation radiograph. (d) One-year review showing formation of new bone

Splinting was done for the upper anteriors for tooth stability in 21and 22. Endodontic therapy was initiated under rubber dam isolation and working length confirmed using apex locator. Irrigation was done with 3% NaOCl followed by 17% EDTA for 1 min. Calcium hydroxide dressing was changed every week for 3 weeks. Triple antibiotic paste was added to calcium hydroxide as the third dressing change. Subsequently, the canals cleaned, irrigated with normal saline, dried, and obturated with gutta percha cones using cold lateral condensation, and AH plus sealer [Figure 4b and c].

In the second phase of therapy, surgical management was done with periodontal curettage. A full thickness buccal and palatal mucoperiosteal flap was elevated from 11, 21, and 22. The groove was seen clearly extending on to the root surface for about 5 mm. A through debridement and root planning was done in 21. The groove was cleaned with ultrasonics, and sealed with biodentine [Figure 3b]. Bone graft (Sybograft) and PRF (autologous) were mixed and placed on bony defect [Figure 3c], flap repositioned, and sutured using interrupted sutures [Figure 3d]. Postoperative recovery was normal and sutures removed after a week. The splinting was retained and removed after 8 weeks. The tooth remained asymptomatic and reviewed every month. The tooth was asymptomatic after a year, new bone formation seen and probing depth decreased to <4 mm [Figures 4d and 3f].

DISCUSSION

Numerous authors have reported and discussed the clinical implications of palatogingival groove or radicular lingual groove which is a developmental anomaly of maxillary anterior teeth that occurs due to infolding of inner enamel epithelium and Hertwig's epithelial root sheath. This groove is more common in maxillary lateral incisors, and the most common location is midpalatal area of lingual surface followed by distal and then mesial. The presence of this groove in maxillary incisor teeth has been implicated as an initiating factor in localized gingivitis and periodontitis eventually leading to loss of periodontal attachment. Whenever these grooves extend to apical third of root, it results in poor prognosis for retention of the tooth. Displacement of cementoenamel junction, extension of enamel in the groove has been suggested as a possible factor in the progression of localized periodontal disease.[416] This groove shows a broad spectrum of morphologic variations in extent, depth, and complexity.[17] Two classifications were independently put forward by Goon et al. and Gu YG. depending on the type and radicular extent of the groove[1819] [Table 1].

Table 1

Palatogingival Groove Classification

Recognition of palatogingival groove is critical, especially because of its diagnostic complexity and the problems that may arise if it is not properly interpreted and treated. Palatogingival groove has got a reputation for being difficult to diagnose. Meticulous clinical and radiographic examination are needed for correct diagnosis and planning therapy in such cases. Two-dimensional limitations of radiographs are not sufficient to understand the complex anatomy of root canal system in such an anomaly. However, with the advent of cone-beam tomography, early diagnosis, and timely treatment has become possible. This has proved to be of great advantage as it demonstrated the dimensions of groove, its communicating nature, the site of bifurcation, the volume of bone loss and thus, the approximate amount of graft required for filling the defect.

Treating combined endoperio lesions are a clinical dilemma because making a differential diagnosis and deciding a prognosis are difficult. A four phase treatment algorithm guidelines have been proposed in managing the endodontic-periodontal combined lesions, namely, presurgical phase (determining periodontal/regenerative prognosis), endodontic phase, periodontal surgical phase, and post-GTR reevaluation protocol.[20]

On comparison of the root developmental groove and the palatogingival groove similarities such as the increased cementum thickness, decreased dentin thickness, pulp compartment surface alteration, irregularity of the dentin-cementum junction, and of the cementum surface are seen which suggest a common determining factor to this structure organization pattern. It is possible that the palatogingival groove could be the result of an alteration of genetic mechanisms, rather than a dental germ folding, as previously hypothesized.[21]

On microscopic examination of the palatogingival groove, accessory foramina were found not only in the groove, but also in the corresponding wall of the pulp chamber. Accessory canals were the primary means of communication between the pulp and the periodontium of the incisors with a palatogingival groove and lack of closure of the calcified tissues along the groove, allowing for direct connection of the pulp and the periodontium was not found.[22]

Successful treatment of the palatogingival groove depends on the ability to eradicate inflammatory irritants, by eliminating or sealing the groove. Procedures such as radiculoplasty have been advocated to eliminate the groove. Sealing the groove has been tried with different materials after preparation and conditioning ot the groove.[23] Glass ionomer cements, mineral trioxide aggregate, composites, and amalgam are materials that have been used to seal the groove. Intentional replantation for management of palatogingival groove has been reported where the groove extended to the apex of the tooth. Maintaining the viability of the periodontal ligament and intact cementum are key to avoid resorption later. Placing the tooth in saline solution to prevent drying of the periodontal ligament, replanting it within 8 min followed by stabilization have been suggested to ensure reattachment.[24]

In this report, a method using ultrasonics to clean and prepare the groove and subsequently seal it with a bioactive dentin substitute was tried [Figure 5]. Prognosis of this developmental defect depends on location, depth, and extension of groove and the quantum of destruction of periodontal attachment apparatus. When shallow and located only in the coronal structure odontoplasty and periodontal therapy is done, but if deep and pulpal involvement is present then treatment is complex.

Figure 5

(a) Withdrawal of blood. (b) Platelet rich fibrin. (c) Bioactive dentin substitute. (d) Bone graft. (e and f) Guided tissue regeneration membrane

PRF is prepared by collecting blood without adding anticoagulant and centrifuging it immediately. This results in three layers of material with the central layer of a leukocyte and PRF clot. PRF is a complex biomaterial organized as a dense fibrin scaffold, with a specific slow release of growth factors. A number of growth factors such as transforming growth factor type beta 1, platelet-derived growth factor-AB, vascular endothelial growth factor, and glycoproteins such as thrombospondin-1 are released for at least 7 days.[25] Because the PRF is autologous the risk of rejection or disease transmission is avoided and is economical.

In this case report, we used a blend of PRF and bone graft (sybograft) material and a GTR membrane (periocol) [Figure 5]. A combination of barrier materials and bone graft was found to result in a greater attachment gain and bone fill. The use of PRF along with bone grafts accelerates repair and regenerative processes.[26] After the placement of the mix of PRF and bone graft material, the GTR membrane was placed as a barrier between the gingival flap and the defect before flap repositioning and suturing. The objective of membrane barrier procedures is to guide the proliferation of different tissues during healing after therapy (selective cell repopulation).[27]

The combination technique of ultrasonic preparation of the groove, sealing with a bioactive dentin substitute, use of a blend of PRF and bone graft in the defect, along with a barrier GTR membrane resulted in successful treatment outcome and improved clinical parameters.

Bioactive dentin substitute (Biodentine) stimulates cell growth, induces hydroxyapatites formation on the surface of the material when exposed to the simulated body fluid.[28] Biodentine supports periodontal ligament fibroblast cell adhesion and can be used as a root repair material.[2930] Michel et al. investigated the effect of calcium silicate cements on primary human gingival fibroblasts, alveolar osteoblasts, human osteoblast cell line and concluded that they remain the paramount biologic choice for the repair of extensive cervical root defects.[31] Biodentine was good at sealing, formation of new mineralized tissue, histopathologic results and can be considered as an adequate furcation perforation repair material.[32]

CONCLUSION

The clinician's awareness about prevalence and existence of such an anomaly would lead to an accurate diagnosis paving way for elimination of the contributing factors and adequate healing of tissues resulting in successful outcome of therapy.

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.