Successful treatment of osseous lesion associated with palatoradicular groove using local drug delivery and guided tissue regeneration: A report of two cases.

Developmental grooves are not rare and often appear on maxillary lateral and central incisors and are an important predisposing factor to localized periodontal disease. Various techniques have been adopted to eliminate the groove and regenerate lost periodontium. This report of two cases describes the technique of using the local drug delivery system with chlorehexidine and the guided tissue regeneration (GTR) to control the disease progression and regeneration.

Microbial plaque is the primary etiologic factor of inflammatory periodontal disease.[1] Local factors such as root anomalies, crowding, rough or overhanging dental restorations enhance the retention of microbial plaque, causing a local inflammatory reaction. This results in breaching of tooth epithelial attachment leading to a local periodontal defect.[2]

The palatoradicular groove is one such common root anomaly, which is also known as radicular groove, palatogingival groove, and distolingual groove.[3] It is defined as a developmental, anomalous groove found on the palatal aspect of maxillary central and lateral incisors,[4] extending from the cingulum apically on to the root surface.[5] This is formed by an infolding of the enamel organ and the epithelial sheath of Hertwig during odontogenesis.[2]

Withers et al. have reported the incidence of palatoradicular groove to be 8.5%, whereas others have found it to be only 2.8-3.0%. The incidence is higher (18%) in Chinese populations, indicating a racial link.[2] The maxillary lateral incisors are the most frequently affected teeth, with a prevalence ranging from 2.3 to 5.6%.[3]

Although it is not a very frequent anatomic finding, greater plaque accumulation, gingival inflammation, deeper probing depths, and greater attachment loss are observed in maxillary incisors with this defect.[6]

The purpose of this article is to describe the two different treatment modalities [local drug delivery (LDD) system and regenerative surgical] for localized periodontal bone defect associated with palatoradicular groove. To our knowledge, this is the first case report of palatal groove treated with LDD.

Case Reports

Case 1

A 29-year-old female patient reported to the Department of Periodontics with a complaint of progressive spacing between maxillary right central and lateral incisors. The patient reported a history of composite restoration 2 years back in relation to tooth #7 in a private dental clinic. Following 6 months of restoration the spacing gradually increased with mild pain, mobility, and purulent discharge.

Intraoral soft tissue examination revealed that oral hygiene status (score 0.9; OHI-S, Green and Vermilion) was compromised in relation to tooth #7 due to overhanging composite restoration showing marginal and papillary inflammation, and sinus scar on the attached gingiva, associated with purulent discharge from the sulcus. Palatogingival groove was noticed in #7 as shown in Figure 1a. Probing pocket depth measuring >10 mm mesial to tooth #6 and distal to #7 was associated with pathological mesiolabial migration and grade-II mobility. Periapical radiograph revealed overhanging restoration with cup-shaped alveolar bone loss as shown in Figure 1b.

Figure 1

(a) Photograph showing palatogingival groove with deep periodontal defect. (b) Preoperative radiograph showing arc-shaped radiolucency associated with maxillary right lateral incisor. (c) Photograph showing the placement of chlorhexidine chip. (d) Eighteen months follow-up radiograph showing substantial decrease in size of the radiolucency

Considering the clinical and radiographic findings, the case was diagnosed as localized chronic periodontal abscess in relation to tooth #7. Initial treatment included Phase I periodontal therapy with systemic medication (Amoxicillin 500 mg tid, Metronidazole 400 mg bid, Diclofenac Potassium 50 mg bid for 5 days), chlorhexidine mouth wash, and oral hygiene instructions. The patient was not willing for the periodontal flap surgery. Thorough root planing was performed to eliminate the palatal groove and supragingival groove was smoothened using diamond burs to prevent the local accumulation of plaque. Then, the patient was followed initially for 3 months.

Later, LDD with chlorhexidine (CHX) chip (Periocol-CG®, Eucare Pharmaceuticals, Chennai, India) was carried out at 3-, 6-, and 9-month intervals in order to control the periodontal disease activity, as shown in Figure 1c.

After 18 months of follow-up, significant amount of reductions with respect to mobility, bleeding on probing, pocket depth (5 mm), and gain in attachment (3 mm) was observed from baseline. Significant regeneration or bone fill was also observed in radiograph as shown in Figure 1d.

Case 2

A 25-year-old male reported to the Department of Periodontology with a chief complaint of bleeding gums during brushing, for a period of 6 months. Patient revealed no positive medical history and systemic illness. The periodontal examination showed that there was bleeding on probing with increased probing depth in upper left central incisor (#9), measuring about 8 mm on the mesiolabial side, 5 mm on the midlabial, distolabial, and distopalatal side, and 9 mm on the mesiopalatal and midpalatal aspect with grade-I mobility. Upon probing, it was found that a palatoradicular groove originated from the cingulum and extended apically to the mesial aspect of the root surface [Figure 2a]. The tooth was vital. On radiographic examination, an arc-shaped radioluceny was seen in the middle and apical one-third of the root surface, with loss of lamina dura.

Figure 2

(a) Photograph showing raised full-thickness periosteal flap revealing deep intrabony defect and the palatal groove. (b) The groove is planed and collagen membrane is placed over the bone graft. (c) Four months postoperative radiograph revealing new bone filling the defect

Based on the clinical and radiographic findings, a diagnosis was made as “localized periodontitis in relation to #9 with a palatoradicular groove”. A periodontal regenerative surgical therapy was chosen to treat the infrabony defect. The patient received a session of oral prophylaxis, including scaling and root planning, and proper oral hygiene instructions. The papilla preservation flap was selected to gain access to the bony defect, and bone graft combined with resorbable barrier membranes were used to induce periodontal regeneration.

Under local anesthesia, sulcular incisions were made around #8, 9, and 10, and a semilunar incision was given on the palatal aspect at the base of the interdental papilla between #8 and #9. A complete mucoperiosteal flap was elevated on both the labial and palatal sides, exposing the entire bony defect. A palatoradicular groove was clearly visible in the middle one-third of the root surface after removal of granulation tissue. The palatal groove was eliminated (radiculoplasty) by means of a surgical length high-speed diamond periodontal bur under constant water spray. Later, the root was planed with manual instruments (Gracey curettes, Hu-friedy®, N.Rockwell, Chicago). Then, root conditioning was done using tetracycline HCL (100 mg/ml) for 3 min. A demineralized, freeze-dried bone graft [Osseograft®, Advanced Biotech products (P) Ltd., Chennai, India – Joint Venture with Encoll Corp., USA] with saline was grafted into the bony defect, after which a resorbable type I collagen membrane (Healiguide®, Advanced Biotech Products Ltd.) was placed over the graft to cover 2–3 mm beyond the bony defect as shown in Figure 2b. The flap was positioned back and stabilized with simple interrupted suture. Postoperatively, Amoxicillin 500 mg tid for 7 days, Diclofenac potassium 50 mg bid for 5 days, and 0.12% CHX mouthwash 2 times a day for 4 weeks were prescribed. Suture removal was done after a week.

Discussion

Although different treatment modalities like scaling and root planing, odontoplasty, amalgam restoration, and tooth extraction[6] have been proposed to treat palatogingival groove and associated periodontal bone defects, they do not frequently lead to the regeneration of the lost periodontal tissues. Hence, the treatment approaches should be aimed to 1) eliminate or at least flatten the radicular portion of the groove, 2) regenerate the periodontal attachment and bone loss and consequently improve the clinical conditions, and 3) prevent bacterial recolonization of the defect-associated area.

In case 1, to control the disease progression and promote regeneration, we opted for LDD system using CHX chip. CHX is a chlorophenyl biguanide and a symmetrical molecule consisting of four chlorophenyl rings and two biguanide groups connected by a central hexamethylene bridge, with the two positive charges on either side of the hexamethylene ring.

It has broad-spectrum antibacterial action against a wide range of vegetative gram-positive, gram-negative bacteria, yeast, fungi, facultative anaerobes and aerobes, and certain viruses like HIV. At low concentrations, the agent is bacteriostatic, and at higher concentrations, it is rapidly bactericidal.

CHX chip (Periocol-CG) is a small, orange-brown rectangular chip, rounded at one end for insertion into periodontal pockets. It is a biodegradable film of fish collagen matrix into which 2.5 mg of CHX gluconate has been incorporated and cross linked with glutaraldehyde, glycerin, and water. Each chip weighs approximately 7.4 mg and resembles a baby's finger nail measuring approximately 4×5 mm and 0.35 mm thickness.[7]

The CHX chip releases and maintains CHX concentration in the gingival crevicular fluid to greater than 100 μg/ml for at least 7 days, which is well above the tolerance of most of the oral bacteria.[7] Thus, by limiting most of the periodontal pathogens, it prevents the disease activity and may aid in healing of the periodontium by regeneration.

Killoy[8] and Jeffcot et al.[9] in 1998 have shown that controlled-release CHX chip can reduce the probing depth and improve the attachment level. Similarly, in the present case, there was significant reduction in probing pocket depth, bleeding on probing, attachment gain, and bone fill during 18 months of evaluation.

In case 2, the guided tissue regeneration (GTR) technique was used. The principles of regeneration have been studied since the 1970s, when Melcher[10] suggested that the periodontal ligament cells have the ability to promote new cementum, periodontal ligament, and bone formation (periodontal regeneration). Later, Nyman et al.[11] in 1982 confirmed that the periodontal ligament cells have the ability to reestablish connective tissue attachment, once the contact between the gingival connective tissue (and epithelium) and the root surface is prevented by the use of a barrier. Anderegg and Metzler[1] reported 10 cases of palatoradicular groove treated using GTR with significant reduction in probing depth (5.0±0.8 mm) and gain in attachment level (5.3±0.9 mm). Jeng et al.[12] reported a case in which tooth #7 was successfully treated by radiculoplasty, bone graft with demineralized freeze-dried bone allograft, and placement of a non-absorbable membrane. Postoperatively, substantial resolution of the osseous defect and about 7 mm of probing attachment gain was recorded.

One of the main goals of periodontal regenerative surgical therapy is to obtain and maintain primary soft tissue closure above the bony defect during the healing period, and thus ensure protection to the blood clot for the healing process.[13] In this case report, primary soft tissue coverage above bony defect was accomplished by means of papilla preservation flap.

In the present case, the defect was deep and wide where there was less possibility of containing the blood coagulum during the healing period. Hence, demineralized, freeze-dried bone graft and a resorbable type I collagen membrane was used as the periodontal regenerative materials. A resorbable collagen membrane has demonstrated to have the ability to prevent the apical migration of epithelium along the root surface during periodontal wound healing without requiring a second surgery for membrane removal.[3] A bone graft was combined with GTR since in addition to reducing the dead space for tissue ingrowths, it also prevents the overlying membrane from possible collapse.[12] The use of bone graft and GTR to treat this bony defect resulted in a significant improvement in the clinical parameters, with bone filling the defect after 4 months [Figure 2c].

Conclusion

Effective recognition of the palatoradicular groove is critical due to the diagnostic complexity and the periodontal problem that may arise if they are not properly interpreted and treated. Although several studies have reported the clinical evidence of arresting the disease progression by CHX, to our knowledge for the first time, presenting radiographic evidence of periodontal regeneration in osseous defects with palatoradicular groove using CHX as local drug therapy. Further controlled studies to confirm the advantages of this technique over conventional treatment modalities are required.