Plastic surgery

PART IV

HEAD AND NECK

CHAPTER 38  CRANIOFACIAL AND MAXILLOFACIAL PROSTHETICS

GEORGE C. BOHLE III, CHERRY L. ESTILO AND JOSEPH M. HURYN

INTRODUCTION

Prosthetic rehabilitation of the oral cavity and the head and neck is a critical component of rehabilitation following tumor extirpation, trauma, and congenital deformities.1,2 Recent advances in imaging and manufacturing have improved surgical planning by virtual surgery and the availability of custom craniofacial prosthetics. Prosthodontists are important members of the interdisciplinary team who care for the head and neck patients.

Prosthetics for head and neck reconstruction can be categorized based on the anatomic location of the defect. For example, a variety of custom or prefabricated implants and corresponding prostheses are available for acquired defects of the palate, mandible, or external features of the face. When used in this manner, dental and craniofacial implants serve a functional role, aiding in mastication or separating the oral and nasal cavities, or a cosmetic purpose camouflaging scars or improving facial appearance. Custom prostheses can be constructed to replace missing nasal or auricular tissues matching the patients’ skin color and tone. Similarly, prostheses may be used to replace all periorbital tissues after orbital exenteration. Careful analysis of the defect and functional purpose of the prosthesis are integral steps in fabrication.

HARD PALATE DEFECTS

Hard palate defects result from oncologic resection, trauma, or congenital defects. The purpose of prosthodontic rehabilitation is to separate the oral and nasal cavities so that speech and swallowing function are restored. The prosthesis also serves to restore cosmetic appearance by supporting the cheek and lip.

A variety of classification schemes have been proposed by head and neck surgeons, reconstructive surgeons, and prosthodontists for acquired defects of the hard palate based on the individual roles of these groups in the multidisciplinary treatment of head and neck defects3-5 (Chapter 39). For example, head and neck or oral surgery classification schemes describe the anatomical structures to be removed and possible approaches for the operation. In contrast, classification systems proposed by plastic and reconstructive surgeons primarily address the missing anatomic structures and algorithms for reconstruction. Lastly, the prosthodontic systems describe the size and location of the defect and the proposed prosthetic rehabilitation for the patient.

Ideally, patients are evaluated by a prosthodontist prior to surgical treatment. Inevitably, however, some patients present after flap reconstruction. In either case, the goal of prosthodontic rehabilitation is a well-fitting, rigidly supported obturator that provides maximum functional and cosmetic outcomes. In many cases, this process involves a series of prostheses designed to allow wound healing and changes in shape and size due to scarring and adjuvant radiation treatment. Most patients have an surgical obturator fabricated prior to surgery and placed in the hard palate defect at the time of the operation. This is followed by an interim obturator when the immediate wound healing issues have been resolved. Finally, patients are fitted with the definitive obturator.

During the preoperative visit, patients are counseled to provide a realistic functional prognosis of the expected outcomes. In addition, a complete intraoral and head and neck examination is performed to evaluate dentition and anticipated prosthetic shape, size, and fixation technique. Impressions of the maxillary and mandibular arches are made at the initial consultation. In general, patients with healthy dentition and smaller defects have better overall comfort and efficacy of the obturator. Obviously, patients who have loss of periodontal support and resultant loose teeth, active caries, fractured teeth, or heavily restored teeth have more difficulties with hard palate prostheses. In some cases, the use of dental implants should be considered for patients missing teeth in the remaining arch in an effort to provide the maximum obturator stability.

Surgical Prosthesis

The surgical obturator is fabricated prior to surgery and placed intraoperatively to stabilize packing and provide function upon awaking from the surgery.6 Although the surgical obturator can be retained with wires or screws, wires are usually easier and equally retentive in patients with good dentition (Figure 38.1). Typically, a 24 gauge wire is used in a similar manner as arch bars for intermaxillary fixation (Figure 38.2). Bone wax over the cut wire ends is useful to prevent irritation of the cheek and lip. In some cases, the intramaxillary defect is covered with a split-thickness skin graft by the reconstructive team to accelerate tissue healing and optimize postoperative care.

Prosthetic reconstruction of hard palate defects in edentulous patients is challenging, and patients should be counseled that they might experience difficulty with prosthetic function postoperatively. In these cases, placement of dental implants either at the time of the ablative surgery or after recovery is a good option. All available bone should be used to place as many implants as possible with a minimum of two implants. Placement of mini or conventional dental implants can usually be performed with little extension of the overall operating time by placing the implants while awaiting the pathology results of the frozen sections.7 Upon completion of implant placement, the surgical obturator can be held in place with fixation screws, wires, or sutures as outlined above. Alternatively, a 24 gauge wire can be passed in a transalveolar fashion from lingual to buccal (Figure 38.3).

FIGURE 38.1. Surgical obturators. Obturator with fixation screw in remaining hard palate on the left for edentulous patient, and surgical obturator for a dentate patient with wires to wrap around the teeth on the right.

FIGURE 38.2. Fixation of the obturator. Surgical obturator fixated by wires around the remaining teeth, stabilizing the medicated gauze packing and allowing speech and swallowing upon awakening.

Interim Prosthesis

Following a brief recovery period, fabrication of the interim obturator is initiated to account for changes in tissue healing and dentition. This obturator is fabricated using a plastic resin and can be shaved/shaped as needed. The original surgical prosthesis is usually removed 5 to 14 days after surgery, the packing is removed, and the interim obturator is adjusted for gross contact and refined for postoperative changes. This process can be repeated and the interim prosthesis further refined as the patient recovers and the wound contracts. Patients are taught how to place and care for their prosthesis and are typically followed every 2 or 3 weeks for fine adjustments as necessary or until wound healing has occurred. Patients undergoing radiation therapy will usually remain in this interim prosthesis for 6 to 12 months, while those not requiring radiation may be healed sufficiently in 3 months to begin the definitive prosthesis.

In edentulous patients who have previously worn maxillary dentures, the interim obturator can be designed using the previous device, which provides several advantages: the patient is accustomed to the feel of the teeth, the occlusion is known, and cosmetic appearance has not been changed. Resilient lining or tissue conditioners are used to add the obturator portion of the prosthesis after adjusting the denture extensions and roughening the surface to allow adhesion of the new material. In addition, retentive elements can be incorporated into the interim obturator giving the prosthesis greater stability by physically connecting to the dental implants.

FIGURE 38.3. Transalveolar wires passed from palatal to buccal to retain obturator in an edentulous patient.

Definitive Prosthesis

The definitive prosthesis differs from the interim in that it is usually a metallic framework custom cast to fit the remaining teeth and is much stronger than the plastic interim prosthesis. In addition, because healing has nearly completely occurred when the definitive prosthesis is placed, less adjustment is necessary and patients are more accustomed to the feel and routine of wearing a prosthesis.Figure 38.4 demonstrates a well-healed non-reconstructed maxillary defect rehabilitated with dental implants and a definitive obturator. The implants were placed at the time of surgery since the patient had only two remaining teeth to support the obturator.

Prosthetic Rehabilitation of Hard Palate Defects in Patients Reconstructed with Flaps

In some cases, hard palate defects are surgically reconstructed with free flaps (Chapter 39), thereby separating the mouth and nasal cavities with vascularized tissues. These patients are typically referred for prosthetic dental fabrication months after surgery when swelling is decreased and the flap has completely healed. In other circumstances, patients are referred postoperatively after partial or complete flap loss. Failing flap reconstructions may be treated with a prosthesis as an interim measure until the patient can return for additional surgery or as a definitive treatment in conjunction with other measures.

Provided there is physical space available in the oral cavity, a custom prosthesis can usually be fabricated in patients who have undergone flap reconstruction; however, as is the case with all prosthetics, the efficacy of these devices is dependent on the support provided by teeth and dental implants (Figure 38.5). Therefore, bulky flaps that protrude into the oral cavity must, if possible, be reduced in size prior to prosthetic fabrication in order to provide physical space for the prosthesis. Flap reduction is also helpful in stabilizing the prosthetic as the additional weight of a bulky flap usually cannot be overcome with traditional clasps or with implant retentive elements. With a taut flap there is adequate room for the prosthesis, and the patient’s function and cosmesis are greatly improved.

SOFT PALATE DEFECTS

Prosthetic rehabilitation of a soft palate defect is one of the most challenging intraoral treatments a maxillofacial prosthodontist will render. Surgical, traumatic, or developmental alterations of the soft palate alter normal palatopharyngeal closure, resulting in hypernasal speech and food bolus/liquid regurgitation. This muscular sphincter is made of the posterior and lateral pharyngeal walls that move anteriorly and medially to meet the superiorly elevated soft palate to close the oropharynx from the nasopharynx. A speech aid obturator prosthesis allows palatopharyngeal closure in these patients by allowing the lateral and posterior walls of the nasopharynx to contract against the prosthesis. The obturator must therefore be sized precisely to allow unimpeded nasal breathing and should not interfere with the tongue during swallowing and speech.

Velopharyngeal inadequacy (VPI) is the inability of the sphincter to separate the nasopharynx from the oral pharynx. VPI can be caused by one or a combination of the following conditions. Velopharyngeal insufficiency results from loss of anatomic structure from the sphincter. The remaining musculature continues to form some part of the sphincter but there is a physical defect present. This condition is treated by surgery or fabrication of a soft palate obturator. Velopharyngeal incompetency results from an anatomically intact sphincter with muscle incompetency due to disruption of nerve innervation or damage secondary to radiation therapy. All of the muscles of the sphincter are present in complete form but one or more do not function adequately to form the seal, resulting in hypernasal speech and regurgitation of food and fluids through the nose upon swallowing. This condition can be treated with surgery or with the fabrication of a palatal lift prosthesis. By lifting and holding the anatomically intact soft palate in place, the sphincter is restored and speech and swallowing improved.

FIGURE 38.4. Rehabilitation using obturator and dental implants. A. Preoperative panoramic radiograph allowing for the surgical planning of dental implants at the time of ablative surgery. B. Well-healed maxillectomy defect with three dental implants and Locator attachments to retain the obturator. C. The definitive obturator with blue retentive elements to retain the obturator and improve function during speaking and swallowing. D. The final oral rehabilitation of the patient with obturator in place. Dental implants were also placed in the posterior mandible bilaterally giving a stable and functional occlusion. E. Postoperative panoramic radiograph demonstrating well-healed implants and closely guarded remaining teeth.

Patients with acquired defects of the soft palate can have VPI due to direct injury to the sphincter from surgical ablation or develop incompetency secondary to radiation injury. In these cases, a combination of prostheses may be necessary to fill the void left by surgery and support the remaining structure in the closed position. Patients reconstructed with flaps for the soft palate or pharyngeal walls are often more difficult to treat as bulky flaps can impede access to the defect or complicate positioning of the obturator.

Similar to hard palate defects, a series of obturators (surgical, interim, and definitive) is fabricated in patients with expected soft palate defects and based on the same principles, including supporting structures and remaining palatal elements.

Soft palate defects are more difficult to obturate due to the overall length of the prosthesis extending into the pharynx, as well as the muscle activity of the tongue, remaining soft palate, and pharyngeal walls acting on the prosthesis during speech and swallowing. As a result, it is imperative that preoperative mandibular and maxillary impressions capture the extent of the soft palate in order to fabricate a well-extended surgical obturator. The surgical obturator is prepared in the laboratory by approximating the length and height of the soft palate when raised in function (Figure 38.6). Typically, the plane of the hard palate is extended 1 to 3 cm depending on the size of the patient and can be modified in the operating room if excessively long. Just as with a surgical obturator for a hard palate defect, it is usually fixated with 24 gauge wires. Dental implants should be considered for placement at the time of surgery for partially dentate patients and highly recommended for completely edentulous patients. It cannot be stressed enough that the action and weight of the muscles acting on the soft palate prosthesis will require greater support for maximum efficacy in speech and swallowing. Completely edentulous patients will be at a severe disadvantage as their prosthesis will be forced to dislodge anteriorly and inferiorly with function. Routine denture adhesives do little to combat these forces.

FIGURE 38.5. Prosthetic reconstruction after free flap to maxillectomy defect. A. Postoperative panoramic radiograph demonstrating the right maxillectomy and three dental implants. B. Maxillary prosthesis with three retentive elements. Note the smaller posterior size of the prosthesis opposite the retentive elements denoting the change in anatomy from the flap. C. The prosthesis in place retained by the three implants. In this case, the retentive elements were able to overcome the weight of the flap. D. Final oral rehabilitation with maxillary and mandibular removable prostheses in place.

Following surgery, the surgical obturator and packing are removed and the interim prosthesis is delivered. As with the edentulous obturator patient, the existing denture may be converted to the interim prosthesis by fabricating an extension into the surgical defect. One technique uses a wire extension, contoured to the defect, customized with compound impression material, and converted to acrylic resin to match the denture. If implants were placed, then the retentive elements may be incorporated into the prosthesis at this time to give even greater stability and retention.

COMPLEX HARD AND SOFT PALATE DEFECTS

The optimal treatment of complex hard and soft palate defects has been the source of some debate with some authors recommending flaps and others relying primarily on prosthetics. Proponents of surgery have suggested near pre-surgical level of speech intelligibility, good swallowing function, and the comfort of not wearing a prosthesis as well as the necessary adjustments and expense that come with it. Opponents to surgery have suggested that speech is better with a prosthesis as it can be refined as necessary, surgeons will have direct visual access to the defect on follow-up, and swallowing is at a near pre-surgical level. Although widely debated, neither side has shown conclusive evidence to support one treatment method over another. Our studies favor flap surgery for smaller defects and obturator prosthesis for large defects with similar functional results. The approach to each case is planned individually after assessments by our multidisciplinary team and input from the patient.8,9

FIGURE 38.6. Surgical obturator for soft palate defect. A. Preoperative stone cast that has been altered for a surgical obturator extending into the soft palate. B. The completed surgical obturator that will be retained by transalveolar wiring.

MANDIBULAR DEFECTS

Marginal Mandibulectomy Defects

Marginal mandibulectomy defects are created when a segment of the mandible, usually the lingual surface, is removed during oncologic resections to provide a clear surgical margin of oral tumors abutting the mandible. These resections leave the mandible intact, but decrease the height and width of the remaining mandible component. Although a marginal mandibulectomy facilitates intraoral reconstruction by avoiding segmental defects and preserving the mandibular arch, dental reconstruction in this setting can be a challenge due to post-surgical changes in the soft tissue bed. Usually, the buccal and/or lingual vestibules are obliterated, and routine prosthetic extensions are compromised by scarring. Tissue scarring, loose tissues, or bulky flap reconstructions may compromise retention and fit of removable prostheses, thereby limiting their function and the length of time they can be comfortably worn each day. Additionally, inadequate mouth opening or intraoral space may make a fixed prosthesis impossible to fit or to care for with routine daily hygiene.

If possible, the vestibular sulci should be preserved by avoiding primary closure of the tongue or cheek to the resected site, or reconstructed, using a skin graft with a customized prosthesis to shape the recipient bed. In other instances, it may be necessary to revise flaps to decrease bulk and excess soft tissues to improve prosthetic fitting. If postoperative radiation therapy is anticipated, then implants may fare better if placed at the time of ablative surgery. Radiation significantly increases complications and failure rates of dental implant placement.

Surgical resection of the tongue in conjunction with marginal mandibulectomy adversely affects speech and swallowing. Although soft tissue flaps can be used to replace the volume of tissue and provide some mobility to the remaining native tongue, these reconstructions may not restore enough function during swallowing to move the food bolus to the esophagus. In these circumstances, a palatal augmentation prosthesis may be helpful by enabling patients to use their remaining/reconstructed tongue to push the food bolus against the prosthesis and toward the tongue base. These prosthetics are made of acrylic resin and are molded to the palatal vault and held in place with wire clasps. The palatal augmentation portion of the prosthesis is custom molded by having the patient speak and swallow in order to optimize the ability of the tongue to conform to the shape of the palate through its full range of motion (Figure 38.7). It is important to remember, however, that a palatal augmentation prosthesis only assists in transmitting the food bolus to the base of the tongue but does not aid in food transfer to the remaining portions of the alimentary canal.

FIGURE 38.7. Palatal augmentation and soft palate obturator. A. Defect after resection of right base of the tongue, tonsil, and soft palate. B. Palatal augmentation prosthesis combined with soft palate obturator to aid in food bolus transit and swallowing.

Segmental Mandibulectomy Defects

Segmental mandibulectomy defects are reconstructed with osseous flaps or metal plates, or left unreconstructed in some patients due to technical or medical issues (Chapter 37). Patients who have a large, non-reconstructed segmental mandibulectomy defect often have significant cosmetic and functional problems. Unfortunately, in these cases, there is also little that can be done from a prosthodontic standpoint. Most commonly, these patients are referred to physical therapy and a speech and language pathologist to learn exercises designed to enable the patient to consciously bring the native mandible into occlusion during function despite the surgical defect. If possible, these exercises should be initiated early in the postoperative setting as they become increasingly difficult to perform if training is delayed or if radiation therapy is necessary. In some patients, removable guide-flange prostheses may be used; however, in general these devices have limited success in preventing mandible rotation and deviation. Additionally, most patients cannot tolerate these prostheses or are simply unable to fit them in their mouth.

Ideally, segmental mandibulectomy defects are reconstructed with osseous flaps and dental implants placed either at the time of the initial surgery/reconstruction or after healing has occurred postoperatively. Immediate dental implant placement has been significantly improved by recent advances in imaging, software design, and implant fabrication. This approach has the advantage of placing implants prior to radiation therapy and decreasing the number of surgeries necessary for oral rehabilitation. However, immediate dental implant placement increases the operative time and may, in a small number of cases, result in healing complications. As a result, in some patients, dental implants are placed after wound healing and adjunctive treatment has completed.

In most patients who undergo delayed dental implant placement, flap revision is necessary to thin the overlying tissues and to provide a stable keratinized tissue bed for the prosthesis. Patients who undergo dental implant placement following radiation therapy are at risk for developing osteoradionecrosis (ORN) and must be advised appropriately. In some cases, software planning can be used to fabricate implant drill guides designed to minimize soft tissue injury and flap revision and decreasing the chances of ORN.

Dental implants may not be feasible in patients with severe radiation injury, inadequate bone stock, or compromised soft tissues. In these instances, oral rehabilitation is performed using removable prostheses. This process is usually initiated with a provisional removable prosthesis (Figure 38.8) that is subsequently transitioned to a definitive mandibular prosthesis after complete wound healing and tissue remodeling. This prosthesis has a metallic framework and is custom cast to the patients healed but altered anatomy. Although these prostheses provide adequate cosmetic appearance, they are not ideal. They often have inadequate bony support resulting in compromised function and dependence on the native side of the mouth for chewing.

FIGURE 38.8. Oval rehabilitation for pediatric patient after mandible reconstruction with fibula flap. A. Well-healed pediatric patient following fibula free flap reconstruction for osteosarcoma. B. Removable provisional prosthesis allowing for changes in growth and accounting for a mixed dentition. C. Interim oral rehabilitation allowing for future changes as deciduous teeth are lost, permanent teeth erupt, and orthodontic treatment. D. Postoperative panoramic radiograph of fibula free flap reconstruction of left mandible. E. Loss of the buccal and lingual vestibules making prosthesis fabrication and function difficult. F. Definitive removable prosthesis resting on soft tissue of the fibula flap. G. Final oral rehabilitation with a removable prosthesis.

FACIAL PROSTHESES

Defects involving the face are challenging to surgeons and prosthodontists. Reconstructive surgery is limited by the quantity and quality of the donor tissue available that will match the texture and color of the surrounding area. Prosthetic treatment is limited by tissue movement with facial expression or chewing and the fact that prostheses require removal, subjecting the patient to embarrassment. Tissue movements can cause problems with retention and matching because the prosthesis remains immobile. The choice between surgical reconstruction and prosthetic rehabilitation is not always clear. Prosthetic rehabilitation may decrease operative time, thereby decreasing operative morbidity in patients with medical comorbidities. Prosthetics can be easily revised to account for changes in shape or color to improve cosmetic appearance and outcomes in patients with defects in complex structures such as the ear and nose. Finally, surgical and prosthetic reconstruction can be combined in difficult or complex cases to improve the facial appearance.

A physical impression (moulage), digital image, or laser scan of the defect is obtained. Irreversible hydrocolloid, vinylpolysiloxane, or plaster is used to make a mold of the patient’s face or a medical model is made from digital data. The missing anatomy is either hand sculpted or computer milled/printed in wax or clay on the model as well as on the patient for contouring, coloring, and placement of margins. Additionally, the ease of placement of the prosthesis and its retention must be verified as they directly contribute to a successful outcome. Prostheses are designed to use physical undercuts, chemical adhesives, and mechanical retainers either alone or in combination to secure the prosthesis to the face (Figure 38.9 A to E). The type of retention is planned based on the complexity of the surgical site, skin type, and ease of mechanical retention utilizing craniofacial implants or glasses, straps, or clips (Figure 38.9 F to H). Silicon prostheses can be expected to last for 12 to 24 months and are cared for daily with soap and water. With increased sun or chemical exposure, the edges of the prosthesis can begin to breakdown and degrade the color. This color can sometimes be corrected with additional tinting; however, in most cases, a new prosthesis is required every 2 years. A case of prosthetic ear reconstruction is shown in Figure 38.10 and a prosthetic periorbital reconstruction is shown in Figure 38.11.

FIGURE 38.9. Prosthetic reconstruction of the nose after rhinectomy and maxillectomy. A. Patient post maxillectomy and rhinectomy wearing his definitive obturator but in need of a nasal prosthesis. Note the lip contracture and little means of retaining an adhesive prosthesis.B. The facial moulage is poured in stone, and pictured is the magnetic prosthesis that attaches to his obturator and aids in retaining his nasal and lip prosthesis. C. The magnetic attachment is combined with adhesive for retention. There will be some movement, however, as the patient chews due to the connection to the obturator. D. Frontal view of the final prosthesis retained by both magnets and adhesive. E. Profile of the resected tissue and resulting defect. F. Profile view of the restored patient with his magnetic and adhesive retained prosthesis. G.Lateral defect of the nose that could be rehabilitated with adhesive retained prosthesis, however, the patient is legally blind and the caregiver is unable to glue the prosthesis to place. H. The nasal prosthesis attached to his glasses enabling him to reliably position the prosthesis.I. The completed prosthesis and glasses combination.

ADJUNCTIVE MEASURES

Patients with head and neck cancer face secondary sequelae that can impact prosthetic rehabilitation. While advances in the delivery of radiation therapy for head and neck malignancies show promising results, xerostomia, trismus, and the risk of ORN continue to be the most notable issues when developing a prosthetic treatment plan.10 Xerostomia causes a number of problems, including an increased rate of caries that places the teeth supporting the prosthesis at risk of being lost, lack of lubrication for the tissues supporting a removable prosthesis and for the food bolus in swallowing, and loss of the constant flushing action of the saliva to remove food particles from the teeth/prosthesis and buffering of acids after eating. Xerostomia is usually relieved with frequent use of water; however, prescription medications and over-the-counter products can provide some additional relief.11 It is imperative that the patients who have received head and neck radiation therapy have access to fluoride supplements and be instructed to schedule more frequent visits to the dentist for routine examinations.

Irradiation of the masticatory muscles produces fibrosis and leads to acute or chronic trismus resulting in discomfort, difficulty eating solid foods, and impaired dental/oral hygiene. In addition, this complication greatly reduces the ability of medical professionals to visually inspect or perform physical examination to evaluate tissue healing and diagnose recurrent disease. Finally, trismus significantly decreases the potential for dental/oral rehabilitation by decreasing mouth opening and effective placement of functional prosthetics.

Regular stretching of these muscles can decrease and possibly prevent significant limited jaw opening hopefully maintaining an opening of 35 to 50 mm measured from the incisal edges of the maxillary and mandibular incisors. These exercises should begin prior to radiation therapy and resume as soon as possible after surgery to avoid permanent decreased opening.12 The exercises should be performed multiple times per day using manual manipulation with the fingers, tongue depressors stacked together, an acrylic resin “corkscrew,” or commercial devices (Figure 38.12). Early involvement of physiatrists and physical therapists may help patients by providing improved education, support, and encouragement.

FIGURE 38.10. Prosthetic ear reconstruction. A. Well-healed left ear resection for squamous cell carcinoma. B. Definitive auricular prosthesis retained by the remaining anatomy and adhesive.

FIGURE 38.11. Prosthetic reconstruction of periorbital defect. A. The patient with a well-healed tissue bed. B. The wax sculpting is tried to place and refined as necessary to blend with natural contours. C. The final prosthesis retained by the undercut of the superior orbital rim and adhesive. D. The use of glasses is recommended to detract from the prosthesis and to protect the remaining eye.

FIGURE 38.12. From left to right the acrylic resin “cork screw” device, Therabite, and Dynasplint are used to exercise and treat trismus following surgery and radiation therapy.

The third and possibly the most devastating sequelae of head and neck radiation therapy is the risk of ORN. Most literature indicates that the bone irradiated to more than 55 Gy, specifically the posterior mandible, is at high risk for spontaneously or traumatically developing ORN. Several theories continue to be tested in an effort to explain the etiology of ORN whether it is a decrease in blood flow due to damage to fine vasculature or cellular damage making the bone unable to repair itself when insulted.13 In either case, prevention remains at the forefront of treatment planning as ORN may develop at any time during the patient’s life span. Once diagnosed, conservative measures are initially undertaken in the hope that mandibulectomy and free flap reconstruction can be avoided. Hyperbaric oxygen may be helpful.14 Nearly all cases of ORN occur secondary to surgical insult such as tooth extraction. The patient must be informed and constantly reminded that vigilant oral hygiene, frequent visits to the dentist, monitoring sugar and starch intake, and the use of fluoride supplements are a priority. Caries leading to extraction in a highly irradiated field places them at high risk for complication and developing ORN.

References

1.  Kornblith AB, Zlotolow IM, Gooen J, et al. Quality of life of maxillectomy patients using an obturator prosthesis. Head Neck. 1996;18(4):323-334.

2.  Depprich R, Naujoks C, Lind D, et al. Evaluation of the quality of life of patients with maxillofacial defects after prosthodontic therapy with obturator prostheses. Int J Oral Maxillofac Surg. 2010;40:71-79.

3.  Spiro RH, Strong EW, Shah JP. Maxillectomy and its classification. Head Neck. 1997;19:309-314.

4.  Cordeiro PG, Santamaria E. A Classification system and algorithm for reconstruction of maxillectomy and midfacial defects. Plast Reconstr Surg. 2000;105:2331-2346.

5.  Okay DJ, Genden E, Buchbinder D, et al. Prosthodontic guidelines for surgical reconstruction of the maxilla: a classification system of defects. J Prosthet Dent. 2001;86(4):352-363.

6.  Huryn JM, Piro JD. The maxillary immediate surgical obturator prosthesis. J Prosthet Dent. 1989;61(3):343-347.

7.  Bohle GC, Mitcherling WW, Mitcherling JJ, et al. Immediate obturator stabilization using mini dental implants. J Prosthodont. 2008; 17(6):482-486.

8.  Bohle G, Rieger J, Huryn J, et al. Efficacy of speech aid prostheses for acquired defects of the soft palate and velopharyngeal inadequacy—clinical assessments and cephalometric analysis: a memorial Sloan-Kettering study. Head Neck. 2005;27:195-207.

9.  Rieger J, Bohle G, Huryn J, et al. Surgical reconstruction versus prosthetic obturation of extensive soft palate defects: a comparison of speech outcomes. Int J Prosthodont. 2009;22:566-572.

10.  Kubicek GJ, Machtay M. New advances in high-technology radiotherapy for head and neck cancer. Hematol Oncol Clin North Am. 2008;22(6): 1165-1180.

11.  Vissink A, Mitchell JB, Baum BJ, et al. Clinical management of salivary gland hypofunction and xerostomia in head-and-neck cancer patients: successes and barriers. Int J Radiat Oncol Biol Phys. 2010;78(4):983-991.

12.  Stubblefield MD, Manfield L, Riedel ER. A preliminary report on the efficacy of a dynamic jaw opening device (dynasplint trismus system) as part of the multimodal treatment of trismus in patients with head and neck cancer. Arch Phys Med Rehabil. 2010;91(8):1278-1282.

13.  Chrcanovic BR, Reher P, Sousa AA, et al. Osteoradionecrosis of the jaws—a current overview-part 1: physiopathology and risk and predisposing factors. Oral Maxillofac Surg. 2010;14(1):3-16.

14.  Fritz GW, Gunsolley JC, Abubabker O, et al. Efficacy of pre- and postirradiation hyperbaric oxygen therapy in the prevention of postextraction osteoradionecrosis: a systematic review. J Oral Maxillofac Surg. 2010;68(11):2653-2660.