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Delayed Segmental Implant-SupportedOverdenture for a Patient With Partially

Resected Mandible due to AmeloblastomaSushil Kumar Kar1, Arvind Tripathi2, Ravinder Singh Bedi3

ABSTRACT:

Reconstruction following mandibular resection is still verychallenging for prosthodontist. Mandible defects could be theconsequence of ablative surgery for malignancies, huge jaw cysts,infection and trauma. In patients with oral cancers such asameloblastoma, the correct planning of surgery for the tumorresection as well as prosthetic rehabilitation are crucial.Resection of the mandible may compromise orofacial functionand often lead to patients' psychological disorders. Despite veryfrequent use of microvascular flaps, autogenous bone grafts arestill very reliable technique for mandible reconstruction.Comprehensive therapy means not only mandiblereconstruction, but prosthodontic rehabilitation supported bydental implants, which can significantly improve patients'quality of life. The aim of this paper was to present a patientwho had been submitted to mandible resection andreconstruction with autogenous iliac bone graft and subsequentprosthodontic rehabilitation with segmental implant supportedoverdenture anchoraged by ball-socket implants.

Key words: Ameloblastoma, Iliac crest graft, Mandibularreconstruction, Oral rehabilitation

C A S E R E P O R T

doi: 10.5866/2015.7.10077

1Professor2Professor and HeadDepartment of Prosthodontics, Saraswati DentalCollege and Hospital, Lucknow, Uttar Pradesh, India.3Professor and HeadDepartment of Oral and Maxillofacial Surgery,Saraswati Dental College and Hospital, Lucknow,Uttar Pradesh, India.

Article Info:

Received: January 10, 2015Review Completed: February 9, 2015Accepted: March 11, 2015Available Online: April, 2015 (www.nacd.in)© NAD, 2015 - All rights reserved

Email for correspondence:drsushil_kar@yahoo.co.in

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INTRODUCTION:

Ameloblastoma is a aggressive odontogenicepithelial tumor.1 Radiographically, it appears asan expansile radiolucent, with thinned andperforated cortices, and it is known to cause rootresorption. Its most common site of occurrence isthe mandibular molar region. Aggressive resectionis the most effective method of eliminating thetumors.2 This leads to serious complications suchas facial deformity, oronasal and oro-antralcommunications, phonetic difficulties, problems with

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swallowing, loss of teeth and alveolar basal processeswhich cause significant chewing impediments. Toselect a suitable reconstruction method, bone-defectshould be considered first, followed by the soft tissuecondition. With regard to the bone quantity andquality, the best characteristics are provided by theiliac crest. The technique of raising free iliac bonegrafts is simple one, their shape matches mandiblecontours and dimensions and they provide enoughamount of bone that is very significant for implantplacement. Generally, patients experience a

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postoperative course without difficulties, and donorsite complications are rare.

A definitive functional reconstruction impliesprosthetic rehabilitation, which may be done withremovable prosthesis which are retained by meansof the existing teeth. However, apart from thelimited function and discomfort of patient,removable prosthesis also causes an additional boneresorption. Rehabilitation with implant therapy istherefore potentially more acceptable and reliablefor the restoration of masticatory and aestheticsfunctions. An ideal reconstruction is achieved withfixed dentures anchoraged by dental implants.3 Ifbone dimensions are not sufficient, boneaugmentation or adequate implantation systems canbe used. This clinical report describes the functionaland esthetic reconstruction of an adult patient withsegmental implant supported overdentureanchoraged by ball-socket implants following partialresection and augmentation with iliac bone graftsof mandibular ameloblastoma.

Case Report:

A 38-years-old male patient was reported withsegmental reconstructed mandible. Thepostoperative course was uneventful. One year afterthe surgery, a complete graft integration with acertain degree of resorption was radiologicallyconfirmed (Figure 1). Both clinically andradiographically, vertical and horizontal bonedimensions were found to be insufficient forplacement of conventional screw implants (Figure2). A final decision about prosthetic rehabilitationwith sectional removable overdentures supported byimplants was made in agreement with the patientafter having been informed about all the eventualpossibilities.

A good functional denture prior to placingimplants is mandatory before all implant supportedoverdentures. So, a heat processed sectional acrylicdenture was fabricated following the necessaryprotocols. The sectional denture was duplicated andan image guide was fabricated The patient wore theimage guide for the CT scan to determine the sizesand positions of implants .On the basis of the CTscan, the implants selected were having a length of13mm with 3.5mm diameter platform and 2.5mmdiameter Internal Hex. The image guide was thentransferred into a surgical stent. The implantationprocedure was performed under local anesthesia.Intraoperatively, following rising mucoperiosteal

flap, the stability of bone graft was confirmed. Aftersurgical stent adaptation, implantation was doneaccording to the protocol for ADIN dental implantswith Ball Abutments and Cap Attachments (ADINDental Implant System Ltd, Israel). Three implantsat the region of canine, first premolar, first molarwere placed. The tops of the implants were visibleand located slightly above the soft tissue. Healingscrews were placed into the tops of the implants.The patient’s existing denture was relieved andplaced with a soft liner to prevent impingement ofthe implants during the postoperative healingperiod.

The patient was recalled after six months. Acomplete integration of implants was determinedclinically. There were no signs of marginal bone lossaround the loaded implants. The healing screwswere unthreaded and removed and the BallAbutment were screwed into the implant andtightened. A 2 mm height extender was used withthe Ball Abutment to obtain 3 mm of vertical heightfrom the top of the implant at the canine regionbecause the implant in that location was far belowthe occlusal plane after bone resorption (Figure 3).The TE (Tissue Extension) also referred to as theTSI abutment, is the intermediate connectorbetween the implant and the restoration.

Cap Attachment Transfers were placed on theBall Abutments in the patient’s mouth, and CapAttachment Housings were placed over them.Undercuts beneath the Cap Attachment Housingsare blocked out with soft utility wax to prevent theingress of acrylic during the pick-up procedure. Thebase of the patient’s existing denture was carefullyrelieved above the locations of the Cap AttachmentHousings. Autopolymerizing acrylic resin (DPIIndia) was placed into the relieved areas of thedenture and the prosthesis was carefully positionedin the patient’s mouth to pick up the CapAttachment Housings. After the material sets, voidsaround the housings were filled in with additionalautopolymerizing acrylic, and then the tissue-contacting surfaces of the denture were smoothedand polished (Figure 4). Retentive nylon liners werepressed into the incorporated Cap AttachmentHousings in the denture base and its retention wasevaluated on the Ball Abutments in the patient’smouth (Figure 5). The sectional overdentureprovided a group function occlusal scheme. Thepatient was satisfied with the functional and estheticprosthesis, which have performed favorably for one

Delayed Segmental Implant-Supported Overdenture for a Patient Sushil Kumar, et, al.

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year without any visible radiographic boneresorption (Figure 6).

Discussion:

Considering the currently available techniquesfor mandible reconstruction, the question arisesabout which cases are suitable for the reconstructionwith free bone grafts and implants as method ofchoice.4 There are several crucial criteria for adefinite decision making. Favorable tumorprognosis, good health of local tissues, and apatient’s positive attitude with realistic expectations

are important factors for successful treatment. Themajority of authors agree that the iliac crest is thebest donor site, because of easy approach andpossibility for taking a large amount of bone.5 Oneof the dilemmas is whether the reconstructionshould be done simultaneously with mandibleresection or subsequently. Hotz indicates animportant problem of simultaneous reconstructionin cases with malignancies, because it is not possibleto perform a histopathological verification of thetumor free margins.6

Figure 1: Orthopantomograph showing complete integrationof the graft after two years.

Figure 2: Intraoral view after complete healing with deficientheight and width.

Figure 3: Ball abutments placed in the patient's mandible. Figure 4: The finished Sectional removable partial denturewith Cap Attachment Housings

Figure 5: Prosthesis evaluated intraorally for retention. Figure 6: Extra oral view of the patient after oral rehabilitation.

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A contemporary approach to a patient definitiverehabilitation after mandible resection does notimply an anatomic reconstruction only, but also aprosthetic rehabilitation. In the past, patients weremostly rehabilitated with mobile dentures of limitedfunctional and aesthetic values. The introductionof endosteal implants provided rehabilitation withfixed dentures showing to be more comfortable, andsignificantly improving both function and aesthetic.7

When considering the right timing for implantsplacement, there are two reasons in favor of thedelayed implantation. The first is in the fact thatthe successful osseointegration depends onosteoblasts capable for osteogenesis, and anotherreason is that the simultaneous implantation isproportionally more demanding and rarely meetsprosthetic requirements.8 Considering the size of thegraft and the time necessary for remodeling andformation of osteogenetic potential in the presentedcase, the decision was made to place the implantssubsequently, at least after 6 months.

Implant-retained removable overdentures arethe preferred mode of treatment for some authors.9,

10 When compared with a fixed prosthesis, anoverdenture prosthesis allows more flexibility indenture teeth placement. Denture flanges can becontoured to reposition and support the mandibularlip. Access for oral hygiene maintenance is easierfor the patient with overdenture prosthesis. The ball-and-socket attachment allows a full range ofprosthesis motion and maximum contact betweenthe overdenture and the mucosa during mastication.Placing the retentive sockets in the overdenture basereduces hydraulic resistance to coupling and lowersfunctional stresses on the implants.11 For thedenturist, the ability to decrease retention to meetspecific patient needs, utilize the attachments onimplants that are only relatively parallel, andreplace retentive Cap Attachment Nylon Linerswithout the need to reline the denture make thesystem easy to use and maintain. Patients can eat awider range of food items with less difficulty, andexperience significantly greater confidence inconversation, social activities and intimacy thanconventional denture patients. All of these factorscan positively influence patient health and qualityof life.12-14

Conclusion:

The reconstruction of the upper and lower jawwith iliac crest grafts in combination with dentalimplants, leads to satisfactory functional andaesthetic results in patients after the resection of

ameloblastoma. The implant-retained overdenturerepresents the first choice standard of care forpatients with partially resected mandibles.Prosthetic procedures and replacement of retentivesockets are relatively simple, and the ability of thepatient to remove the overdenture facilitates goodoral hygiene.

References:

1. Chauhan DS, Guruprasad Y, Plexiform ameloblastoma ofthe mandible. J Clin Imaging Sci 2011; 1:61.

2. Minichetti JC, D Amore, Schwarz E. Complete OralRehabilitation of a Postresection Ameloblastoma Patient: AClinical Case Report. J Oral Implantol 2011; 37(6):735-744.

3. Goh BT, Lee S, Tideman H, Stoelinga PJ. Mandibularreconstruction in adults: a review. Int J Oral Maxillofac Surg2008; 37(7):597-605.

4. Takushima A, Harii K, Asato H, Momosawa A, Okazaki M,Nakatsuka T. Choice of osseous and osteocutaneous flapsfor mandibular reconstruction. Int J Clin Oncol 2005;10(4):234-242.

5. Ghassemi A, Ghassemi M, Riediger D, Hilgers RD,Gerressen M. Comparison of donor-site engraftment afterharvesting vascularized and nonvascularized iliac bonegrafts. J Oral MaxillofacSurg 2009; 67(8):1589-1594.

6. Hotz G. Reconstruction of mandibular discontinuity defectswith delayed nonvascularized free iliac crest bone graftsand endosseous implants: a clinical report. J Prosthet Dent1996; 76(4):350-355.

7. Lundgren S, Rasmusson L, Sjöström M, Sennerby L.Simultaneous or delayed placement of titanium implantsin free autogenous iliac bone grafts. Histological analysisof the bone grafttitanium interface in 10 consecutivepatients. Int J Oral Maxillofac Surg 1999; 28(1):31-37.

8. Chiapasco M, Colletti G, Romeo E, Zaniboni M, Brusati R.Long term results of mandibular reconstruction withautogenous bone grafts and oral implants after tumorresection. Clin Oral Implants Res 2008; 19(10):1074-1080.

9. Chan MF, Hayter JP, Cawood JI, Howell RA. Oralrehabilitation with implant-retained prostheses followingablative surgery and reconstruction with free flaps. Int JOral Maxillofac Implants 1997; 12(6):820-827.

10. Leung AC, Cheung LK. Dental implants in reconstructed jaws:patients’ evaluation of functional and quality-of-life outcomes.Int J Oral Maxillofac Implants. 2003; 18(1):127-234.

11. Kovacs AF. Influence of the prosthetic restoration modalityon bone loss around dental implants placed in vascularizediliac bone grafts for mandibular reconstruction. OtolaryngolHead Neck Surg 2000; 123(5):598-602.

12. Feine JS, Carlsson GE, Awad MA,et al. The McGill consensusstatement on overdentures. Montreal, Quebec, Canada. May24-25, 2002. Int J Prosthodont 2002; 15:413-414.

13. Firtell DN, Curtis TA. Removable partial denture designfor the mandibular resection patient. J Prosthet Dent 1982;48:437-443.

14. Kratochvil FJ. Defects with mandibular continuity. In:Beumer J III, Curtis TA, Firtell DN, eds. MaxillofacialRehabilitation: Prosthodontic and Surgical Considerations.St Louis: Mosby, 1979.

Delayed Segmental Implant-Supported Overdenture for a Patient Sushil Kumar, et, al.

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