|Year : 2014 | Volume
| Issue : 1 | Page : 50-54
Interdisciplinary approach toward prosthodontic rehabilitation of a mandibulectomy patient
Department of Prosthodontia, Military Dental Centre, Ahmednagar, Maharashtra, India
|Date of Web Publication||21-Jun-2014|
Department of Prosthodontia, Military Dental Centre, Ahmednagar, Maharashtra
Source of Support: None, Conflict of Interest: None
Clinical trial registration jid-101-13
| Abstract|| |
Management of maxillofacial patient with acquired defect of mandible is a challenge related to both control of the primary disease and rehabilitation following the same. The aim of this clinical report is to highlight these difficulties and emphasize the importance of timely initiated interdisciplinary approach and planning to rehabilitate the concerned patient in the best possible manner.
Clinical Relevance to Interdisciplinary Dentistry
- Multidisciplinary management to restore form and function in an acquired defect mandibulectomy patient.
- A timely initiated team approach by prosthodontist, maxillofacial surgeon, plastic surgeon, radiotherapist, psychologist, and speech therapist.
- Prosthetic rehabilitation included the use of maxillary guidance ramp, cast mandibular guide flange and fixed partial dentures.
Keywords: Challenges, interdisciplinary approach, mandibular guidance therapy, suggestions
|How to cite this article:|
Hundal M. Interdisciplinary approach toward prosthodontic rehabilitation of a mandibulectomy patient. J Interdiscip Dentistry 2014;4:50-4
| Introduction|| |
The management of malignant tumors associated with the tongue, the mandible and adjacent structures represent a difficult challenge for the surgeon, radiologist and prosthodontist relative to both control of the primary disease and rehabilitation following the same.  The aim of this clinical case report is to bring forth the significance of timely initiated interdisciplinary interaction and planning by the surgeon and prosthodontist besides other disciplines, that is, radiotherapist, speech therapist and psychiatrist so as to achieve best possible postoperative result in such individuals. ,
| Case report|| |
A 66-year-old retired army officer reported at Command Military Dental Center Northern Command in June 2012 with the chief complaint of chewing and swallowing food, poor control of salivary secretions, impaired speech articulation, gross deviation of mandible, and severe cosmetic disfigurement.
Past dental history revealed that the individual was diagnosed with squamous cell carcinoma of the right lower jaw in 2004 for which radical neck dissection along with hemi mandibulectomy was carried out at PGI Chandigarh in January 2004 [Figure 1]a-c. Radiotherapy and chemotherapy followed. Surgical reconstruction with titanium mandibular plate covered with pectoralis major mucocutaneous flap was done. However due to persistent infection, the reconstruction place was removed in April 2004. No further attempts at surgical reconstruction were made. There was no other relevant medical, personal and family history.
|Figure 1: (a) Radical neck dissection along with hemimandibulectomy on the right side (frontal view) (b) left lateral of patient showing mandibular deviation toward the right side (c) orthopantomogram showing radical neck dissection along with hemimandibulectomy|
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Clinical examination revealed:
- Radical neck dissection along with hemimandibulectomy on the right side
- Missing teeth 13, 25, 26, 35, 36, 37, and 41-48
- Gross deviation of 13 mm measured at mandibular central incisor level in reference to maxillary central incisor toward the right side
- Grade 3 mobility of tooth 31
- Attrited teeth 11, 21, 22, 23, 31, 32
- Four unit porcelain fused to metal fixed partial denture replacing teeth 25, 26 given in 1995 at a Military Dental Center
- Difficult control of saliva altered speech
- Despite the limitations, the patient was optimistic and cooperative toward the attempts at prosthetic reconstruction.
Treatment plan was formulated and carried out so as to best rehabilitate the patient. After consultation with the team of plastic and reconstructive surgeons both at PGI Chandigarh as well as the local Command Military Hospital the option of surgical reconstruction was ruled out; hence, it was decided to rehabilitate the patient with a guide flange prosthesis which was a challenge considering the degree of jaw deviation. The treatment regime consisted of:
- Placing the individual on an exercise program so as to loosen the scar contracture, reduce trismus and improve maxillomandibular relationship
- Extraction of mobile tooth 31
- Root canal treatment for teeth 11, 13, 21, 22, 23, 32, 33, and 34
- Full metal crown for 37
- Porcelain fused to metal crowns for teeth 11, 21, 22, 23, 32, 33, and 34
- Three unit porcelain fused to metal fixed partial denture for replacing tooth 13
- Replacement of old 4 unit porcelain fused to metal fixed partial denture replacing teeth 25, 26
- Mandibular guidance with initially an acrylic maxillary guidance ramp followed by cast metal mandibular guide flange.
After necessary extraction and endodontic treatment the guidance therapy was initiated. To compensate for the severe mandibular deviation of 13 mm the acrylic maxillary ramp was first fabricated and inserted which is much more adjustable than the mandibular guidance ramp [Figure 2]a. The full palatal coverage prosthesis was constructed in acrylic resin using wrought wire retainers following conventional prosthodontic guidelines and then fitted and adjusted in the patient's mouth. An occlusal index of the mandibular teeth was formulated in the palatal ramp at the position where the patient could comfortably manipulate his jaw taking care that this index did not extend below the level of the maxillary teeth so as to avoid any interference with speech, deglutition and other oral functions requiring tongue manipulation. This index initially was much lingual to the maxillary teeth however with repeated and periodic adjustments of the palatal index as the mandible assumed a more desired maxillomandibular relationship combined with the continuous exercise regimen the discrepancy gradually reduced to 5 mm in 4 months period [Figure 2]b and c. It is important to highlight the importance of combined cooperative efforts put in by the patient himself, the motivation and support of his family members as well as the positive counseling provided by the consulting psychiatrist which culminated in such desirable results. As the index approached the maxillary teeth it was necessary to equilibrate certain teeth so as to eliminate cuspal interference.
Once this discrepancy was reduced to 3 mm, insertion of required fixed partial dentures was done following the recommended prosthodontic principals and procedure [Figure 2]d. Initially an acrylic mandibular guide flange prosthesis was fabricated and inserted for the patient and on achieving a satisfactory intercuspal position with nil deviation a cast metal guide flange prosthesis was processed and inserted for the individual [Figure 2]e. However, due to an angular pathway of closure and despite occlusal equilibration a compromised occlusion was achieved at the molar region on the unresected side hence an extension of the cast metal mandibular guidance ramp was made superiorly in a diagonal manner which allowed for normal horizontal and vertical overlap of the maxillary teeth [Figure 3]a and b. Thus with the above followed treatment protocol, the deviation was reduced from a discrepancy of 13 mm to nil at the central incisor level in a time frame of 5 months.
|Figure 2: (a) Acrylic maxillary guidance ramp with occlusal index of mandibular teeth (b) close mouth view showing deviation of 13 mm measured at the central incisor levels (c) mandibular teeth in occlusion with the index in the maxillary acrylic ramp showing the deviation reduced to 5 mm (d) restored maxillary arch with ceramo-metal prosthesis in situ (e) acrylic mandibular guide fl ange prosthesis in situ with no deviation at the incisor region|
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|Figure 3: (a and b) Cast metal mandibular guidance ramp with extended buccal plate on the maxillary teeth (c) frontal postoperative view of rehabilitated patient (d) left lateral postoperative view of rehabilitated patient|
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The patient is under periodic recall and is being monitored to use the guidance ramp prosthesis until the postsurgical scar contracture ceases to a stage where the patient can easily manipulate his jaw to an acceptable occlusal position and until proprioception is established. The importance of the jaw exercise regime, maintenance of oral hygiene as well as care for prosthesis has been discussed and emphasized to the individual who is more than willing to follow the protocol because of his encouraged and positive frame of mind from his successful treatment results [Figure 3]c and d.
| Discussion|| |
The various challenges along with suggestions observed in the rehabilitation of patients with acquired defects of mandible are as follows.
Such patients present a far more difficult rehabilitation problem than patients with maxillary surgical defects. Radical alveolectomy results in loss of vertical mandibular height, vestibular depth, loss of load bearing oral tissues as well as other soft-tissues, which are essential for maximum retention, support and stability of the maxillofacial prosthesis. It also leads to the discrepancy between the level of residual osseous support and the opposing dentition at the level of occlusal plane.  Loss of natural teeth either due to past habit of tobacco usage, neglect in oral hygiene or due to extraction prior to surgery or radiation therapy further compromises the stability of the prosthesis.  Disabilities resulting from mandibular/radical neck dissection include impaired speech articulation,  difficulty in swallowing, deviation of mandible during functional movements, poor control of salivary secretions, and severe cosmetic disfigurement.
0Restoration of surgical defects of the maxilla is readily achieved with prosthesis and on completion of this treatment oral functions are restored within normal limits with little facial disfigurement. In contrast, in patients following mandibular resection, restoration of function is usually not possible and prolonged disfigurement is inevitable. Consequently these patients experience many frustrations with fewer returning to presurgical levels of social function. Rehabilitation is more complicated and requires combined, timely initiated and well planned efforts of many disciplines including surgeon, prosthodontist, speech therapist, psychiatrist, social service workers, dietician and others.
After resection, immediate mandibular surgical reconstruction in the form of alloplastic implants, use of autogenous bone, homographs, and use of osteocutaneous flaps may be undertaken if there was no prior irradiation and if postoperative irradiation is not planned. ,
Surgical alterations aimed at improving prosthodontic prognosis
Minor alterations in surgical resection may greatly enhance the prospects for prosthodontic rehabilitation. Hence, it is extremely important for both the surgeon as well as the prosthodontist to discuss the case before surgery. These alternatives are:
- Whenever delayed reconstruction is planned it is important that internal/external fixation devices should be employed so as to span the resection and maintain the segments in their original position. Furthermore, it is essential to release the small condylar remnant to avoid any damage to the facial nerve which lies perilously close to the remnant. Hence, any planned bony graft should end well below the condyle and glenoid fossa with no attempts to fix the bony segments or to place the end of the graft in the fossa. It has also been observed that iliac crest grafts offer more bone height as compared with the fibula graft for implant placement 
- If reconstruction of mandible is not anticipated, the condyle and ascending ramus should be removed. If the condylar fragment remains, it often is retracted medially and anteriorly and comes to rest in close proximity to the maxillary tuberosities. This displacement prevents proper extension of the maxillary denture and may cause irritation to the mucosa overlying the fragment 
- Bony cuts through the dentulous parts of the mandible should be intraseptal rather than interproximal. This will result in higher levels of bone on that portion of the tooth adjacent to the surgical defect, thus making such a tooth more suitable as a partial denture abutment
- Bony resections through the body of the mandible should be made as posteriorly as possible to improve the prosthetic prognosis particularly so in edentulous patients
- Prior to surgery key teeth to be salvaged should be identified. Retention of mandibular cuspids is especially beneficial
- Some prosthodontists maintain that if the resection does not include the geniohyoid and mylohyoid muscles on the resected side they should be excised. It is claimed that this lessens mandibular deviation and results in more favorable mandibular movement after surgery
- Surgical reconstruction often involves the use of skin grafts and connective tissue grafts including pedicle flaps, free flaps or vascularized bone and soft-tissue grafts. Skin grafts serve as excellent prosthesis bearing surfaces. However, it is important to make the reconstructive surgeon aware of two facts about skin grafts. One, if skin grafting is planned without additional connective tissue grafting every effort should be made to utilize split thickness grafts to avoid incorporation of hair follicles in the graft. Second it is essential to avoid skin grafts if prosthetic rehabilitation is planned with dental implants as skin particularly in the oral environment does not tolerate the titanium surface of implant abutments and the reaction can be quite severe.  Microvascular free flaps are ideal when associated structures in addition to mandible have been resected, particularly in irradiated mandible as besides offering volume to restore bulk they do not tether. However as compared to skin grafts, they are compressible and mobile and hence create an unstable prosthesis bearing surface. 
Most of these patients experience varying degrees of trismus following surgery particularly in those individuals requiring either preoperative or postoperative radiation therapy. Early initiation of well-organized mandibular exercise program along with moist heat and analgesics are effective means of alleviating this disability. These stretching exercises involve guiding the patient to push the mandible away from the defect side towards a more normal position and then while holding this position the patient should open the mouth as wide as possible to stretch the musculature. The mandibular guidance therapy should be used only when the residual mandible can be easily repositioned into its proper alignment by manual guidance with minimal pressure else it may not be successful or even damage the remaining teeth and soft tissues.
Following surgical resection the remaining mandibular segment often is retruded and deviated toward the surgical side at the vertical dimension of the rest (severity and permanence of deviation is highly variable). Upon mouth opening, the level of deviation increases leading to an angular pathway of opening and closing. Scar contracture, tight wound closure and muscle imbalances secondary to the primary resection contribute to this deviation. Rotation is caused by gravity and downward pull of the suprahyoid musculature. The functional results of deviation and rotation of mandible are facial disfigurement, loss of occlusal contact between remaining maxillary and mandibular teeth and compromised lip closure affecting control of saliva and swallowing. There are a number of methods that will reduce mandibular deviation including intermaxillary fixation and use of either mandibular based or maxillary based guidance prosthesis, which should be combined with a well-organized regime. ,
Despite the use of adjunctive guidance therapy some patients may soon attain an acceptable interocclusal relation while others may never be able to. When a usable occlusal relationship is achieved, the mandibular teeth will often occlude one tooth distal to the presurgical cuspal interdigitation. On the nonsurgical side, the buccal slopes of the mandibular buccal cusps function with the central fossae of the maxillary teeth because of mandibular rotation in the frontal plane. Hence, occlusal equilibration is often necessary after guidance therapy has been completed, which is difficult because of the imprecise nature of mandibular movements and nonreproducible centric relation records. Selective crown placement may be required to achieve appropriate interocclusal records.
This is profoundly affected as resection of the tongue and mandible obliterates the lingual and buccal sulci and consequently a means of collecting and channeling secretions posteriorly no longer exists. In addition, the loss of motor and sensory innervations of the lower lip on the resected side adversely affects the oral competency and prevents the patient from detecting secretions escaping from the mouth. Drooling at the corners of the mouth may get infected with Candida albicans. Effective relief is possible with tongue release and vestibuloplasty procedures. The creation of vestibule enables the patient to pool salivary secretions more effectively and allows extension for denture flanges. Esthetics may also be improved since a prosthodontic restoration can now be molded to provide contour and support for the lower lip and cheek.
Additional morbidity contributed by radiation therapy
A high percentage of such patients with related tongue lesions receive pre and postoperative radiation therapy. This results in:
- Severe scarring of tissue bed making it unyielding and more difficult during mandibular guidance therapy
- Radiation therapy predisposes the patient to dental disease due to reduced salivary flow and ascendance of oral carcinogenic organisms. This is compounded by the shoulder and neck disability produced due to radical neck dissection; trismus and compromised motor control of mandible. Topical fluoride application with the use of electric toothbrushes helps alleviate this problem to a certain extent
- In edentulous patients, complete denture use is further compromised by reduction in the volume and change in consistency of saliva in addition to impaired mucosal tolerance
- Lymphedema and venous pooling are accentuated by radiation therapy and may compromise mandibular denture extensions and may predispose to tongue and cheek biting.
Following mandibular resection the oral cavity is reduced in size and portion of the tongue often is excised or used for closure of the wound. The sensory and motor innervation of the tongue, lower lip and cheek are compromised. Mandibular movements are significantly altered. Radiation therapy leading to changes in the volume and consistency of saliva make prolonged speech discourse difficult. These changes result in misarticulation of speech sounds. Use of palatal speech aids was suggested by Cantor et al. in 1969. They reasoned that if the palatal vault was lowered prosthetically into the space of Donders to accommodate for restricted tongue movements, speech improvement may be noted. Others have observed that placement of prosthesis although improves the quality of specific sounds, it does not improve discourse. However intensive speech therapy, does improve speech significantly both with and without prosthesis. 
| Conclusion|| |
To conclude it is imperative to take note of the various challenges and suggestions associated with rehabilitation of individuals who have undergone mandibulectomy with radical neck dissection. Careful presurgical assessment between the surgeon and the prosthodontist can improve the postsurgical rehabilitation of such individuals significantly.
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