Treatment of Intraosseous Cystic Lesions of the Mandible by Conservative Enucleation and Cavity Filling with Allogenic Freeze-Dried Bone Mixed with Autologous Bone Marrow

    

    

    Figure 5:  Six months after surgery. A) Panoramic radiograph showing
complete absence of the lesion. B) Dental prosthetic rehabilitation was
successful.
    
    

Results

Teeth with cystic lesions were treated endodontically in 29 (69.0%) patients and apicectomy was carried out in 19 (45.2%) of these patients. The mandibular third molars, unerupted teeth, and teeth with cystic lesions were removed in 20 (47.6%) cases. Postoperative hemorrhage occurred in one (2.4%) patient. Wound dehiscence occurred in two (4.8%) patients, and the wounds healed secondarily. All patients showed satisfactory healing. Dental rehabilitation including prosthesis and implant provision was successful in 10 (23.8%) patients. Facial appearance and oral function were normal. The patients were followed for 13-48 (mean, 29.9) months using panoramic radiography. Recurrence was seen in 2 (11.2%) patients with KCOTs (Table 1). Clinical and panoramic radiography showed no residual or recurrent cyst in the remaining patients.

Discussion

In the past few decades, numerous studies have investigated the treatment of jaw lesions using autogenous grafts, allogenous grafts, xenografts, or alloplastic and synthetic grafts as filling materials. In addition to reducing infection and healing disturbance, these materials have been used to accelerate bone regeneration, prevent soft-tissue collapse into the defect, and improve bone strength [3]. Autologous bone has repeatedly been reported to represent the gold standard of bone grafting, and the iliac crest is the most frequently chosen donor site because the iliac spongiosa provides osteoconductive, osteoinductive, and osteogenic properties [4]. However, clinical reports of jaw defect filling with autogenous iliac bone after cyst enucleation are rare.

One study showed that bone density was significantly greater in patients with cystic lesions of the jaws who underwent enucleation and bone grafting with demineralized freeze-dried bone allografts than in those whose defects were packed with an absorbable gelatin sponge. This finding demonstrated that decalcified freeze-dried bone allografts enhanced bone healing in jaw defects after cyst removal [2]. Horowitz et al. [5] reported the use of Kiel bone xenografts in combination with autologous aspirated bone marrow to graft 20 cystic jaw defects. Sixteen (80%) cases were successful. Results were evaluated by clinical and radiographic follow-up of the patients for up to 4 (average, 2.3) years after surgery. Causes of failure were reported to be the inability to create a water-tight closure, followed by immediate secondary infection, rather than host rejection [5]. The use of mineralized bone substitutes, such as β-tricalcium phosphate or hydroxyapatite, leads to complete ossification of large defects after 12 months [6]. In the present study, facial appearance and oral function were normal. Two cases of KCOT cyst recurrence were observed at 33 and 42 months postoperatively. Clinical and panoramic radiography showed no residual or recurrent cyst in the remaining patients. We believe that defect filling using allogenic freeze-dried bone combined with bone marrow following conservative enucleation is a simple, safe, and reliable alternative treatment for large intraosseous cystic lesions, including dentigerous cysts, KCOTs, and aneurysmal bone cysts.

The treatment of cystic jaw lesions using a combination of allogenic freeze-dried bone and bone marrow reduces infection and healing disturbance, accelerates bone regeneration, prevents soft-tissue collapse, and improves bone strength. The preferred treatment of these lesions is cyst enucleation, and the resultant cavity can be filled with different materials to accelerate bone healing and provide an adequate quantity and quality of regenerated bone for the subsequent placement of prostheses or implants. Our results showed that facial and oral function were normal in all patients and that dental rehabilitation, including prosthesis and implant provision, was successful in 10 (23.8%) patients. Accelerated bone healing is due to the osteoinductive and osteoconductive effects of allogenic freezedried bone, which contains osteoinductive proteins [7,8]. Ondrus et al. [9] reported that the application of tricalcium phosphate mixed with autologous bone marrow can achieve better and faster healing of benign bone lesions than the application of tricalcium phosphate granules alone.

The World Health Organization has described the tendency of an odontogenic keratocyst to progress to a KCOT based on the wellknown aggressive behavior of this lesion, its histology, and new genetic information [10]. KCOTs comprise approximately 11% of all cysts of the jaws [11]. Madras et al. [10] reported that the 29% recurrence rate in their case series was consistent with previously established data, and all recurrence occurred within 2 years post-intervention. In our case series, recurrence was observed at 33 and 43 months in 2 (11.2%) patients with KCOTs treated with enucleation. The recurrent KCOTs were small lesions and could be treated by simple excision. In our study, intraosseous cystic lesion of developmental origin presented with malignant degeneration.

The wounds were monitored daily for primary wound healing. Two (4.8%) patients developed wound dehiscence, which may have been due to excessive tension and premature suture removal, and the wounds healed secondarily. Wound closure with less tension and delayed suture removal may prevent wound dehiscence.

The results of this study support the clinical application of allogenic freeze-dried bone mixed with autologous bone marrow as an alternative, viable filling material for intraosseous cystic lesions of the mandible removed by conservative enucleation.

References

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