Treatment of combined endodontic: periodontic lesion by sealing of palato-radicular groove using biodentine.

INTRODUCTION: Palatoradicular groove is a developmental anomaly which is predominantly found in maxillary lateral incisors. It provides a susceptible alcove for the progression of localised periodontal inflammation which can further cause pulpal involvement. This case report describes the successful treatment of a large periodontic - endodontic lesion usingnon surgical endodontic therapy and biodentine for the sealing of the palatoradicular groove.

INTRODUCTION

The palato-radicular groove can be defined as a linear depression or a groove which starts at the junction of the cingulum with one of the lateral marginal ridges and continues apically to the proximal surface of the root,[1] possibly reaching the apex.[2] Radicular grooves are quite variable in their depth and also the distance and direction traversed down the root.[3] The various terms used to describe this anomaly are: Palato-gingival groove,[4] developmental radicular anomaly,[5] disto-lingual groove,[6] radicular lingual groove,[7] palato-radicular groove,[8] radicular groove[9] and cingulo-radicular groove.[10]

The radicular grooves are classified into three types on the basis of severity: Type I, the groove is short (not beyond the coronal third of the root); type II, the groove is long (beyond the coronal third of the root) but shallow, corresponding to a normal or simple root canal; and type III, the groove is long (beyond the coronal third of the root) and deep, corresponding to a complex root canal system.[11]

Lee and colleagues[1] hypothesised that the palatal groove represents an infoldingof the enamel organ and Hertwig's epithelial root sheath and analogous to the pathogenesis of dens invaginatus. Ennes and Lara[12] suggested that the palatal groove could be the result of an alteration of genetic mechanisms, rather than a dental germ folding. The prevalence rate of palato-radicular groove has been reported to be 2.8%-8.5% with a predisposition for Chinese population.[13] Due to the close approximation of the radicular groove with the periodontal tissues it provides a pathway for bacteria to penetrate into the periodontal ligament area causing localised inflammation.[5] Once there is disruption of the periodontal attachment and the groove is involved, a self-sustaining localised periodontal pocket can develop along the length of the groove. Treatment management for the radicular groove, include curettage of the affected tissues[14], saucerisation with a round bur[15], sealing of the groove with a biocompatible material[15], root canal therapy as primary or secondary endodontic lesion is involved[16] and surgical procedures (i.e., guided tissue regeneration therapy, intentional replantation.[131718] The purpose of this paper is to report a case involving a maxillary lateral incisor with a type III deep palatal groove and associated large periapical lesion. A combined treatment approach involving both non-surgical endodontic therapy and periodontal surgical management resulted in periodontal healing and resolution of the periradicular radiolucency.

CASE REPORT

A 22-year-old female reported with a chief complaint of swelling in relation to upper left lateral incisor. On clinical examination there was a palatal swelling in relation to # 7 [Figure 1b], draining sinus tract on the labial alveolar mucosa that had been present for approximately 2 months [Figure 1a], increased periodontal pocket depth of 10 mm on the palatal aspect, negative response to thermal and electric pulp vitality tests while the adjacent teeth responded normally. The patient did not reveal any prior trauma to the maxillary anterior region and had no history of pain in relation to #7. The patient had no significant tenderness to percussion or palpation in the maxillary anterior region. Periapical radiographs revealed an extensive periradicular radiolucency involving the apical one-third of the root on the maxillary right lateral incisor [Figure 2a]. The facial sinus tract was traceable with a gutta-percha cone to the periapical radioluscency in relation tooth #7. The radiograph also showed the presence of two narrow vertically oriented radiolucent lines extending from the cervical portion of the crown upto the entire length of the root. Based on the tests and the radiographic findings, the diagnosis was necrotic pulp with periapical granuloma and moderate localised periodontitis secondary to the palatal groove on tooth #7. At this appointment the patient was informed that tooth #7 had a questionable long-term prognosis related to the length and depth of the radicular groove. At the same appointment tooth #7 was accessed and the single root canal was cleaned and shaped using stainless steel hand files and NiTi rotary instruments, irrigated with 5.25% sodium hypochlorite and filled with calcium hydroxide paste (UltraCal XS, Ultradent Products, Inc.) [Figure 2c]. The access opening was then sealed with Cavit (3M, ESPE). Two weeks later, the root canal was instrumented to size #50 with Protaper universal rotary files. (Protaper Universal rotary system, Dentsply, Tulsa Dental). Canal was debrided with Endovac Irrigation system(Discus Dental) using 5.25% sodium hypochlorite and 2% chlorhexidine, rinsed with 17% EDTA followed by full strength NaOCl, filled with calcium hydroxide and sealed with Cavit. Obturation of the root canal system was completed 3 weeks after the initial visit. Root canal was irrigated with 5.25% NaOCl, rinsed with 17% EDTA, and dried with paper points. The root canal was obturated with gutta-percha and sealer (AH Plus, Dentsply Maillefer, Tulsa, OK) [Figure 2d].

Figure 1

(a) Preoperative clinical picture showing draining sinus in relation to tooth # 7. (b) Presence of a palatal swelling and a deep periodontal pocket of 10 mm on the palatal aspect. (c) Palatal full thickness flap refection. (d) Exposure of palatoradicular groove and removal of the granulation tissue. (e) Placement of Biodentine into the groove. (f) Flap repositioning followed by suturing (g) Complete resolution of palatal swelling and draining sinus (h) in relation to tooth #7

Figure 2

(a) Preoperative radiograph showing presence of a large periapical radioluscency and two vertical lines extending from the cervical aspect of the crown till the root apex in relation to tooth #7.(b) Gutta percha tracing of the sinus tract and gingival sulcus on the palatal aspect of tooth #7 (c) After placement of Calcium hydroxide into the root canal (d) Immediate post obturation radiograph (e) Immediate post operative radiographic after surgical f ap reflection and sealing of radicular groove.(f) Follow up radiograph at 6 months showing excellent healing

After completion of endodontic therapy, the patient was referred to the Department of Periodontics for evaluation of tooth #7. At this evaluation appointment 1 month later, the patient was asymptomatic, but the labial sinus tract had not yet resolved and the sulcus adjacent to the palatal groove could be traced with a gutta-percha cone to a depth of 10 mm. Upon further consultation with the periodontist, an exploratory surgery was planned. After flap access, a narrow palatal bony defect was noted extending 10 mm from the adjacent bony crest. The soft tissue filling the bony defect was removed and the root surfaces exposed to the defect were planed with an ultrasonic scaler and hand curettes. Odontoplasty was performed on the palatal aspect of the root, followed by filling of the groove with Biodentine, mixed and placed according tothe manufacturer's instructions [Figures 1c-g and 2e]. Following surgery, the patient was placed on amoxicillin 500 mg, thrice a day dosage for 5 days. In addition, a 0.12% chlorhexidine gluconate rinse was prescribed and ibuprofen was given to relieve discomfort. Postsurgical healing was excellent. At 6 months post-surgery, the facial sinus tract had resolved and 2 mm non-bleeding sulcus was present at the site of the palatal groove. A periapical radiograph taken at 6 months follow-up demonstrated excellent bone fill of the osseous defect [Figures 1h and 2f].

DISCUSSION

The case report described here suggests the treatment of type III palatoradicular groove. The anatomy of a type III groove is the most complex and presents more difficulties in diagnosis and treatment.[11]

The rationale behind the selected treatment plan was the following:

Removal of granulation tissue followed by saucerisation of the groove followed by sealing to eliminate bacterial colonisation;

Reduction of periapical radioluscency and pocket depth by regeneration of periodontal attachment.

The palatogingival groove acts as a nidus which allows for bacterial plaque accumulation and serves as a communicating channel between external environment and periodontal tissues leading to the development of a combined endodontic-periodontal lesion which can infect the pulp in a retrograde manner possibly due to communication between the pulp canal system and the periodontium through the accessory canals. This might even lead to it being misdiagnosed as a primary endodontic lesion. The diagnosis might further be intricate as the clinical picture might suggest a periodontal abscess and radiographically the palatoradicular groove might appear like a vertical root fracture or an extra root canal.[13]

In this case biodentine has been used for the sealing of the groove due to its superior handling characteristics and excellent biocompatibility. Biodentine has been successfully used in sealing of palatogingival groove and as a retrograde restorative material.[1819] In a study carried by Perard et al.,[20] using a spheroid model they concluded that the biocompatibility of biodentine is similar to that of MTA. Biodentine also has an equal efficacy as that of MTA in pulp-capping treatment during vital pulp therapy.[21] In a study by Zhou et al.,[22] it was concluded that Biodentine caused gingival fibroblast reaction similar to that by MTA and can be safely used in procedures requiring close approximation with the periodontal tissues. Biodentine is preferred over MTA due to its better handling characteristics and short setting time whereas when using MTA in sealing of radicular groove it is difficult to control moisture during the setting of MTA causing degradation and poor marginal seal.[23]

A combined treatment approach was used for the treatment, requiring non-surgical management for the treatment of periapical lesion and a surgical approach for exposing the radicular groove, followed by odontoplasty and filing of the groove with Biodentine. Removal of the microbial irritants and sealing the potential routes of communication between the external environment and the periodontal tissues initiates the process of healing, thus allowing bone deposition into the defect and reattachment of periodontal ligament fibres to the surface of biodentine due to its biostimulative effects. The treatment regimen thus employed was successful as it can be observed that 6 months post-surgery, the sinus tract had resolved, a 2-mm healthy gingival sulcus is restored in relation to the palatal groove, radiographic evidence of bone fill at the site of the periradicular lesion. The greatest concern in this case has to be the long-term success of tooth #7 related to potential for future periodontal breakdown in that area.

CONCLUSIONS

Palatoradicular groove if left unattended may predispose the maxillary incisors to attachment loss. This case report involved a maxillary lateral incisor with a type III palatoradicular groove and associated periodontal and pulpal involvement. The treatment outcomes that have been achieved in this case are clinical attachment gain (8 mm), no increase in gingival recession, and the disappearance of the periapical radiolucency, thus emphasizing the fact that complex interdisciplinary approach can have hope for teeth with extremely poor prognosis.