## 4 Discussion  
The authors suggested a conservative method that allows patients to manage hygiene on their own. This method combines the advantages of the previous dressing materials, and dressing material can be applied easily with an accurate position. Orascar showed a sealing effect by adhesion with the gingiva after a few minutes of application. The dehiscence of these three patients was acceptable, and secondary healing was achieved without complications, such as bacterial infection and graft failure, within four weeks of the wound dehiscence occurrence.  
Wound dehiscence can critically affect the bone graft results associated with exposed bone substitutes and membrane. In particular, the porosity of the titanium mesh can allow contamination with oral bacteria if the mesh is exposed after graft surgery. Therefore, exposure of the titanium mesh is a complication with a high risk of bacterial infection [1; 9]. Regarding case #3, secondary healing was achieved with the exposed titanium mesh using Orascar with an omnivac split. The buccal gingiva grew into the dehiscence area under the titanium mesh. The quality of the bone graft was acceptable for a dental implant that did not require additional graft surgery.  
Regarding the bone graft results, the timing of exposure is a crucial factor. Many studies reported that premature exposure (within 4 weeks after the graft) significantly affected bone healing, including total graft failure, infection, and inevitable additional graft surgery [10; 11]. In these case reports, the dehiscence occurred within 3 weeks (Table 1). On the other hand, all cases achieved secondary healing without complications, such as infection, graft failure, and poor oral hygiene. Although some bony fragments on the dehiscence area of case #2 showed insufficient integration with bone healing at postoperative 10 weeks, histology revealed a chronic fibrosis aspect without bacterial invasion through this conservative treatment. In addition, the other remained bone grafts had well-integrated and healed during 12 months after the bone graft. (Figure 5D).  
Zinc oxide without eugenol (COE-PAK\({}^{\circledR}\), Coe Laboratories Inc., Chicago, IL, USA) is one of the most famous oral dressing materials, and has high stability and fixation on the oral mucosa, but it is difficult for the patient to reattach the dressing and manage oral hygiene while maintaining the dressing. Neither zinc oxide nor eugenol (Orascar\({}^{\circledR}\), TBM, Gwangju, Korea), used in this case series, was easy to manage because it could form an adhesive film in response to the saliva. In addition, its main composition of ethyl cellulose is widely used to prepare pharmaceutical dosage forms, which is non-toxic, stable, compressible and inert polymer [12]. To be available for the dehiscence on the bone graft, however, it should be applied to the appropriate position to be sealed and protected from oral bacteria. Therefore, the omnivac splint with an engraved Orascar was used as a guide to the exact position by the patient. Through this technique, the patient could maintain their oral hygiene and reported no discomfort for food intake.  
The bone substitutes of autogenous bone and DDM/rhBMP-2, used in this research, were the graft material, which might induce secondary healing and resist infection [13]. Therefore, it is unclear if the validation of this conservative treatment will be effective for other bone substitutes without osteoinductivity, such as alloplastic and xenografts. Although this method could prevent infection and allow secondary healing, the amount of bone healing was insufficient. Further research will be needed to develop a dressing material that contains a growth factor to promote soft and hard tissue regeneration.