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 Table of Contents  
Year : 2020  |  Volume : 12  |  Issue : 2  |  Page : 95-97

Case study – Rehabilitation after removal of an extensive odontogenic keratocyst: Treatment in big bone defects

1 Department of Oral and Maxillofacial Surgery, Hanover Medical School, Hanover, Germany
2 Department of Dentistry, Krems an der Donau, Danube Private University Center for Digital Technologies in Dentistry and CAD/CAM, Austria

Date of Submission15-Jan-2020
Date of Decision20-Mar-2020
Date of Acceptance04-Apr-2020
Date of Web Publication21-May-2020

Correspondence Address:
Marcus Schiller
Department of Oral and Maxillofacial Surgery, Hanover Medical School, Carl-Neuberg.Strasse 1, D-30625 Hanover
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJDS.IJDS_7_20

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Odontogenic keratocysts are not uncommon in dental practice. Besides the removal of the cyst, regular follow-up checks are also important, as they facilitate early diagnosis and treatment of recurrent cysts. The successful removal of the cyst is followed by prosthetic rehabilitation. The focus should be on the objectives of restoring the patient's ability to chew and on resolving any issues affecting speech. Using templates for the implantation procedure ensures the correct positioning of the implants. If a template is used, any additional augmentation that may be required can be performed precisely at the site of the planned implantation, thus preventing over-augmentation.

Keywords: Guided implantation, jaw reconstruction, odontogenic keratocysts, particulate bone grafts

How to cite this article:
Schiller M, Rahlf B, Jehn P, Alevizakos V. Case study – Rehabilitation after removal of an extensive odontogenic keratocyst: Treatment in big bone defects. Indian J Dent Sci 2020;12:95-7

How to cite this URL:
Schiller M, Rahlf B, Jehn P, Alevizakos V. Case study – Rehabilitation after removal of an extensive odontogenic keratocyst: Treatment in big bone defects. Indian J Dent Sci [serial online] 2020 [cited 2020 Aug 11];12:95-7. Available from: http://www.ijds.in/text.asp?2020/12/2/95/284673

  Introduction Top

Odontogenic keratocysts have an incidence rate of 10%–20%, making them the third most common type of cysts affecting the jaw, after radicular and follicular cysts.[1],[2],[3] They occur as unicystic or multicystic lesions and affect the mandible twice as often as the maxilla. They are particularly common in the region of the mandibular angle.[4] In 1956, Philipsen was the first to identify and describe an odontogenic keratocyst as one of the most aggressive kinds of odontogenic cysts.[5] As it has characteristics of a malignant tumor, it was first classified by the WHO as a keratocystic odontogenic tumor in the 2005 update on head-and-neck tumors.[6] In 2017, keratocystic odontogenic tumors were moved from the neoplasm group to the cyst group.[7] Odontogenic keratocysts have a recurrence rate of approximately 25%.[8],[9]

  Case Report Top

In June 2015, a 28-year-old male soldier, a smoker, presented with symptoms affecting his left mandible. He reported having had an odontogenic keratocyst surgically removed in an inpatient procedure 3 years ago. On intraoral examination, 37, 36, 35, 31, 41, and 42 (ISO System) were found to be missing, with otherwise sufficiently well preserved residual dentition. The patient also reported beginning hypoesthesia in the region of the left inferior alveolar nerve. X-ray imaging [Figure 1] showed extensive osteolysis from 36 to 38 and a fixation plate with a non-osseointegrated bone fragment. The patient underwent 3D imaging (cone-beam computed tomography [CBCT]) and a plaster model of the mandible was produced. His planned treatment included removal of the new cyst and augmentation of the defect with bone particles from the retromolar region of 38, removal of the fixation plate, and insertion of implants at 42, 31, 35, 36, and 37 as well as augmentation at 42 and 31.
Figure 1: X-ray with the defect on the left side

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The first operation was performed under sedation in late July 2015. Once anesthesia had been induced, the mandible was exposed from 35 to 38 using an incision along the alveolar ridge followed by periosteal dissection. The fixation plate and the bone fragment were removed, and using a nerve-sparing approach, the osteolytic lesion was enucleated [Figure 2] and histopathologically examined. The next step was to use a bone scraper to collect bone material from the region of 38 to augment the defect. At the end of the surgical procedure, a resorbable membrane cover (Bio-Gide®, Geistlich Biomaterials, Wolhusen, Switzerland) was applied and Vicryl was used to achieve tension-free wound closure (Vicryl® 3.0; Ethicon GmbH and Co. KG, Norderstedt, Germany). Postoperative X-ray imaging showed the defect where the cyst had been to be filled.
Figure 2: Situation after excochleation

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Histopathology showed a plenty of granulation tissues with proliferated capillary blood vessels, fibroblasts, and macrophages, without residual odontogenic keratocyst.

Three months later, the patient returned for the second surgical procedure. During this operation, implants were inserted at 35 (Straumann SLActive® SP 3.3 RN, length: 10 mm, Institut Straumann AG, Basel, Switzerland), 36 (Straumann SLActive® BL 4.1 RC, length: 10 mm), and 37 (Straumann SLActive® BL 4.1 RC, length: 10 mm). Augmentation was performed at 31 and 42. The implant positions were determined using the planning software coDiagnostiX™ created by Dental Wings Inc., Montreal, Canada. To achieve this, the model was digitized, exported in open STL format, and matched with the CBCT data. The use of a guided template ensured not only the exact positioning of the implants but also the extent of required augmentation.

Once anesthesia had been induced, an alveolar ridge incision was made from 34 to 38, with an additional distal relieving incision, and from 31 to 42. When the mucoperiosteal flap was mobilized, the former defect was found to be completely filled with bone. Using a piezosurgical approach, a retromolar block was harvested in the region of 38 and bone grafts were extracted with the bone scraper. The bone block was affixed to 31 and 42 with osteosynthesis screws and the gap between the graft and the recipient site was filled with bone particles. Finally, a resorbable membrane was applied (Bio-Gide®, Geistlich Biomaterials, Wolhusen, Switzerland). Following periosteal incision, tension-free wound closure was achieved with Vicryl (Vicryl® 3.0; Ethicon GmbH and Co. KG, Norderstedt, Germany). Guided insertion of the three implants at 35, 36, and 37 was followed by the mucoperiosteal flap being replaced and sutured (Vicryl® 3.0; Ethicon GmbH and Co. KG, Norderstedt, Germany). Postoperative X-ray imaging showed the graft in situ and good positioning of the implants.

The next procedure was followed 4 months later. A local anesthetic was injected at 31–42 and 34–37. A crestal incision from 31 to 42 and from 35 to 37 was then performed and a mucoperiosteal flap prepared. The osteosynthesis screws were removed. Good osseointegration of the graft had been achieved so that it was possible to insert two implants (Straumann SLActive® BL 3.3 NC, length: 8 mm, Institut Straumann AG, Basel, Switzerland) before suturing the flap back in place (Vicryl® 3.0; Ethicon GmbH and Co. KG, Norderstedt, Germany). The cover screws at 35–37 were removed, appropriate healing caps were inserted, and the wound edges were sutured with Vicryl (Vicryl® 3.0; Ethicon GmbH and Co. KG, Norderstedt, Germany). Postoperative X-ray [Figure 3] showed proper positioning of the implants at 31 and 42.
Figure 3: X-ray after implantation

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Another 3 months later, the implants at 31 and 42 were also exposed.

Prostheses were fitted between August and October 2016. The first step was to take an open-tray impression of the implants in place. The single-tooth crowns (base metal, PFM for 35 and 36, full-cast base metal for 37) and the bridge from 31 to 42 (base metal, PFM) were then manufactured in the dental laboratory. The bridge was attached to the implants with screws and the single-tooth crowns were cemented.

Since then, the patient has regularly returned for follow-up checks so that 4 years later, the implants remain stable, as X-ray imaging shows [Figure 4].
Figure 4: X-ray 4 years later

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  Discussion Top

The removal of the cyst with subsequent prosthetic reconstruction was a critical aspect of treatment. The choice of treatment method should always depend on the individual patient's age, the location of the cyst, any affected adjacent structures, possible multiple occurrences, and the time since a previous surgery.[10] Postoperative follow-up checks are very important to identify any recurrences as soon as possible.[11] Recurrence is most likely within the first 5–6 years after the initial surgery.[8],[12]

As the present case shows, odontogenic keratocysts may grow to a considerable size. For this patient, removing the cyst and filling the bone defect with particulate bone graft in one operation and then inserting dental implants in another was considered the definitive treatment of choice. As an infantry soldier, the patient must be able to perform physically demanding activities. Extensive defects in the jaw area can lead to fractures when stress is applied, be it on deployment or at home. Examples of such stress that are relevant to soldiers include the chin straps on their helmets and the fact that protective or breathing masks must be tight fitting to be effective. The implants were placed using guided surgery to ensure the correct positioning of the prosthetic. Single-tooth crowns for the lateral teeth facilitate good oral hygiene. The bridge in the region of the anterior mandible was deliberately not cemented but screw retained to facilitate checking and cleaning of the implants. Four years later, the patient's bone structure remains good and there are no signs of recurrence. The soldier is once again fit for duty and combat, with no residual impairment.

This case shows that though the treatment of large cysts may be complex and prolonged, very good outcomes without aesthetic or functional impairment are possible.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

We acknowledge support by the German Research Foundation (DFG) and the Open-Access Publication Fund of Hannover Medical School.

Conflicts of interest

There are no conflicts of interest.

  References Top

Godhi SS, Kukreja P. Keratocystic odontogenic tumor: A review. J Maxillofac Oral Surg 2009;8:127-31.  Back to cited text no. 1
Johnson NR, Gannon OM, Savage NW, Batstone MD. Frequency of odontogenic cysts and tumors: A systematic review. J Investig Clin Dent 2014;5:9-14.  Back to cited text no. 2
Jones AV, Craig GT, Franklin CD. Range and demographics of odontogenic cysts diagnosed in a UK population over a 30-year period. J Oral Pathol Med 2006;35:500-7.  Back to cited text no. 3
Brannon RB. The odontogenic keratocyst. A clinicopathologic study of 312 cases. Part I. Clinical features. Oral Surg Oral Med Oral Pathol 1976;42:54-72.  Back to cited text no. 4
Philipsen HP. Keratocyster (Kolesten-Tomer). Tandialgebladet 1963;60:963.  Back to cited text no. 5
Barnes L, Eveson JW, Reichart P, Sidransky D. Pathology and Genetics of Head and Neck Tumours. Third edition. WHO Classification of Tumours, Vol. 9; 2005.  Back to cited text no. 6
Soluk-Tekkeşin M, Wright JM. The World Health Organization classification of odontogenic lesions: A summary of the changes of the 2017 (4th) Edition. Turk Patoloji Derg 2018;34. doi: 10.5146/tjpath.2017.01410.  Back to cited text no. 7
Johnson NR, Batstone MD, Savage NW. Management and recurrence of keratocystic odontogenic tumor: A systematic review. Oral Surg Oral Med Oral Pathol Oral Radiol 2013;116:e271-6.  Back to cited text no. 8
Bornstein M, Filippi A, Altermann HJ, Lambrecht T, Buser D. The odontogenic keratocyste, odentogenic cyst or benign tumor. Schweiz Monatschr Zahnmed 2005;115:111-22.  Back to cited text no. 9
Eufinger H, Machtens E. Odontogenic keratocyst evaluation of 107 cysts in 49 patients. Dtsch Zahnärztl Z 1994;49:172-3.  Back to cited text no. 10
Piatelli A, Piatelli M, Di Petta T Primordial cysts or kerato cysts. Zahnärztl Prax 1986;37:126-30.  Back to cited text no. 11
Nitsch A, Rottwinkel N, Gruber R, Merten HA. The keratocyst: Diagnostic problems and chances of success ZWR 2005;114:373-81.  Back to cited text no. 12


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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