Fresh–Frozen Allogenic Bone Graft Usage in Treatment of an Odontogenic Keratocyst in the Mandible

Round 1

Reviewer 1 Report

Dear Author Thank you very much for an interesting case Report. The usage of allograft materials is starting to grow worldwide, and its scope of usage is more and more sophisticated. The study outcomes and limitations a very nicely written.   Concerning the reviewed article, please clarify: -if the biopsy had to be performed? -are there any cases of prophylactic titanium plate insertion in cases of late pathological fractures? -should allograft material be placed in some special conditions? -if the patient would decide on dental implants, would there be any necessary secondary surgery or approaches?

 

Author Response

Dear reviewer thank You very much.

Response to Reviewer 1 Comments

 

Point 1.  – Dear Author Thank you very much for an interesting case Report. The usage of allograft materials is starting to grow worldwide, and its scope of usage is more and more sophisticated.

Response 1: Thank you very much. Im very happy that the study study is interesting. This makes me want to publish even more, thank you.

 

 

Point 2.  – The study outcomes and limitations a very nicely written.   

Response 2: Thank you very much.

 

 

Point 3.  – if the biopsy had to be performed? 

Response 3:) Thank you very much. In cases of big lesions, status of dental roots, spread beyond the cortical bone and  furthermore factors related with pateints age, history of asymptomatic lesion – the diagnostic biopsy should be done. In some rare cases some cystic lesion can me an ameloblastoma – which recquire some different surgery type; and secondly ther are like 0,5-1% cases of and squamous cell carcinoma – SCC- mural type present when a classic benign odontogenic cyst is present in the bone for a period of many years – because of this rare, but still possible malignant transformation (patient aged 60+), a biopsy should be performed, because a carcinoma also changes the diagnosis and further surgical approach and the scope of surgery.

 

 

Point 4. - are there any cases of prophylactic titanium plate insertion in cases of late pathological fractures? 

Response 4: Thank you very much for the question. Ofcourse there is always a possibility of a late fracture.  I have also two similar cases with big odontogenic tumors and cysts that becuase of their size and progression - not beyond only the buccal but also lingual cortical plate recquired some prophylactic plating. So far after years, the patients didnt want to remove the plating systems and are very well adapted with ofcourse no reoccurence of the cyst/tumor. Prophylactic plating is not only case related: big lesion, invasion of both cortical plates, spread towards the inferior border of the mandible, but also with general conditions, such as patients age (osteoporosis) and further onces like if patient is still actively working, if patient will be fully cooperative after the surgical period and if the patient will want to use either dental prosthesis or dental implants. Then the plate should be removed after the period of bone consolidation, -6months.  On the other hand, pathological fractures are quite rare, and mostly associated with cases of actively working uncooperative patients, without bone reconstruction/regenerations, when big bone cavities are left to heal on its own without any grafting procedures. In such cases its possible to encounter a late pathological fracture. In my practise there was no such a case, however in the world literature there are some cases reported.

 

 

Point 5. - should allograft material be placed in some special conditions?

Response 5: Thank you very much for the question. This topic is quite interesting. It is all related with the condition and presence of the bony walls surrounding the defect. Secondly the defect should be clean, without any debris, possible bacterial infection from inflammated cyst wall, occurence of purulent fluid within the tumor/cyst cavity. Thirdly the bone structure should be stable and free of any pathological fractures, so that the grafted bone will heal properly- if not a plate/mesh insertion because of a pathological fractures (prsent by the time of surgery) or a prophylactic approach (because of possible fracture in the future, and loss of good and stable patients own bone) should be considered to ensure the grafted material stability and good accurate position of grafted material (no movements or dislocation of gratfed bone). The next topic should include the usage of any collagen membranes and the ability to ensure the best of possible methods for a close and tight suturing of the mucosal flaps to compeltely cover and close the grafted area. Usage of allograft should be also discussed with patient, so that all treatemnt possibilities are known and established. This is quite interesting topic and could be discusses a lot. Thank you very much.

 

 

Point 6. - if the patient would decide on dental implants, would there be any necessary secondary surgery or approaches?

Response 6: Thank you very much for the question. Becuase of some degree of vertical bone loss because of the usage and pressure applyied from dental prosthesis the amounf of bone present is suitable to place a dental implant. On the other hand from aesthetic point of view, additional graft, split-ridge technique of possible sedondary grafting procedure with xenograft+titanium mesh and immedialte dental implant placement could be used also, mostly because of the shape and superior part of the bone volume. When this technique would be used a more satysfing result would be achieved. Ofcourse its not mandatory from functional point of view, only the aesthetical one. Lastly, a simple dental implant placement is possible but it wouldnt be related with later improved prosthodontics to ensure good shapoe, volume and position of either prosthetic bridge, crown or some dental precision elements used for improved retention of dental prosthesis. There are a few possibilities. On the other hand if the patient would decide for implants he should be aware of some additional costs and time necessary to improve bone volume and then place dental implants.

Author Response File: Author Response.pdf

Reviewer 2 Report

The description of the case becomes very long and tiresome to read. I suggest to simplify as much as possible.

 As reported by the authors, treatment is enucleation of the cyst together with curettage. Unlike other odontogenic cysts, odontogenic keratocyst often tends to recur after treatment, which happens in about 25-60% of OKC patients. Do the authors consider that allograft bone packing is safe under these conditions?

 The use of allograft fresh frozen bone has some reticence. There are some biological aspects, such as the possible transmission of infections and its potential immunogenicity. What controls did the graft receive prior to clinical use?

The conclusions do not follow from their work. The authors should write them according to the advantages they have obtained in the use of their technique and in the use and safety of the use of fresh frozen allograft.

Author Response

Dear reviewer thank You very much.

Response to Reviewer 2 Comments

 

Point 1.  – The description of the case becomes very long and tiresome to read. I suggest to simplify as much as possible.

Response 1: Please provide your response for Point 1. (in red) Thank you very much. Authors will try to slighlt reduce the article size in order to met all the necessary recquirements from all reviewers. Secondly, case should be well documented and discusses. Authors would want to thank the reviewer for some great hints. Thank you

 

Point 2.  – As reported by the authors, treatment is enucleation of the cyst together with curettage. Unlike other odontogenic cysts, odontogenic keratocyst often tends to recur after treatment, which happens in about 25-60% of OKC patients. Do the authors consider that allograft bone packing is safe under these conditions?

Response 2: Thank you very much for the question. Because we already knew its an OKC, an additional bone ostectomy was used. With the help of surgical burrs, all bony walls can be easily drilled to improved better surgical margins. So far we have a lot of OKC cases, and only 5% was reltaed with a reoccurence because of lack of bone ostectomy. Perhaps this ostecomy, consisted of bone drilling could increase the diamater of bone defect or be dangerous for some vital structures (like nerves, vessels), it grants a very good result. Secondly when allograft bone is placed it grants some major advantaged- it can be easily evaluated in CBCT/CT rtg panx studies (evaluation of bone healing and remodeling is very much visible, sam as possible re-occurence); it grants more bone stability and reduces the healing period and decreases the risk of pathological fractures. We all believe that it is a safe and good method, especially for detailed monitoring of bone structures.

 

Point 3.  – The use of allograft fresh frozen bone has some reticence. There are some biological aspects, such as the possible transmission of infections and its potential immunogenicity. What controls did the graft receive prior to clinical use?

Point 3.  – Thank you very much for the question. Allografts have good healing ptoential but recquire some improved conditions for healing and good would closure, free of bacteria, saliva and other debris. Authors only used the allograft bone from secure blood-bank stations where all the bone specimens are fully evaluated in the scope of viral, microbiological and other factors. Secondly because of a cooperation between blood banks and patomorphology deparments all specimens are clearly evaluated and certified. After the following Among the most important steps in processing bone is the elimination of bone marrow and cellular debris with fluid and detergents, which, by its clearing effect, will improve the osteoconductive capacity of the bone. The main ways to preserve bone are through freezing at −0°C, in liquid nitrogen at −196°C, or freeze-drying = and ofcourse the freeze-drying has a logistical advantage in that it allows further storage of the tissue at room temperature. Bacterial sterilisation is achieved at the usual dose of 25 kGy if the bone has been properly managed before final sterilisation. Finally, alle bone blocks, either spongious, corticomedullary or other are packed in a protective environement.  All allograft material is prepared accoring to - European Union: Directive 2004/23/EC of the European parliament and of the council of 31 March 2004 on setting standards of quality and safety for the donation, procurement, testing, processing, preservation, storage and distribution of human tissues and cells. Official Journal of Eur Union 2004, L102:48–58.

 

Point 4.  – The conclusions do not follow from their work. The authors should write them according to the advantages they have obtained in the use of their technique and in the use and safety of the use of fresh frozen allograft.

Response 4: Response 1: Please provide your response for Point 4. (in red) Thank you very much. The authors will try to improve the conclusions.

 

Author Response File: Author Response.pdf