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The aim of the study was to investigate the microbial colonization (by Candida species, anaerobic and facultative anaerobic bacteria) of maxillary obturators used for the restoration of maxillary defects, including during radiotherapy., Retrospective cohort study., Fifteen patients requiring a maxillary obturator prosthesis had swabs of their obturators and adjacent tissues taken at different stages of their treatment over a period of 8 years., Identification of microbial species from the swabs was carried out using randomly amplified polymorphic DNA polymerase chain reaction (RAPD PCR) analysis, checkerboard DNA-DNA hybridization, CHROMagar Candida chromogenic agar, and DNA sequencing., Candida species were detected in all patients and all patients developed mucositis and candidiasis during radiotherapy which was associated with an increase in colonization of surfaces with Candida spp . , particularly C albicans . Microbial colonization increased during radiotherapy and as an obturator aged, and decreased following a reline, delivery of a new prosthesis, or antifungal treatment during radiotherapy., Microbial colonization of maxillary obturators was related to the stage of treatment, age of the obturator material, radiotherapy and antifungal medications, and antifungal treatment may be recommended if C albicans colonization of palatal tissues is greater than 10 5 colony-forming units per cm 2 following the first week of radiotherapy., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Maxillofacial prosthetics includes restoration of maxillary defects resulting from resection of palate and nasosinus neoplasms with obturator prostheses which may be colonized by microorganisms and function as a reservoir of infection. Patients with neoplasms commonly also require radiotherapy that can result in changes in saliva quality and quantity and changes in the oral microbial flora. The altered flora, in individuals immunocompromised from cancer therapy, increases their risk of prosthesis-related infections., Objectives: In this review article, we explore microbial biofilms, their main components, mechanisms of microbial adhesion, and stages of biofilm development. We also discuss the different materials that are used for manufacturing maxillary obturators, their characteristic features, and how these can affect microbial adhesion. Furthermore, we shed some light on the factors that affect microbial adhesion to the surface of maxillary obturators including tissue proteins, protein adsorption, and the acquired enamel pellicle., Conclusions: The conclusions drawn from this literature review are that it is imperative to minimize the risk of local and systemic infections in immunocompromised patients with cancer having maxillary defects. It is also important to determine the role of saliva in microbial adhesion to obturator materials as well as develop materials that have a longer life span with surface characteristics that promote less microbial adhesion than current materials.

Prosthodontic rehabilitation of a patient with an atrophic edentulous mandible presents a significant challenge in restoring esthetics and function. The purpose of this clinical report is to describe fracture of an atrophic edentulous mandible opposing maxillary natural dentition in association with endosseous dental implants. The patient received two wide-diameter implants in the anterior mandible for an implant-assisted mandibular overdenture, in which the implants penetrated the inferior border of the mandible for bicortical stabilization. Three months following implant placement surgery, the patient experienced pain, swelling, and intraoral purulent drainage around the right implant. Panoramic radiograph revealed a fracture of the mandible through the right implant site and signs of infection around the left implant. The implants were removed surgically, and open reduction and fixation of the fracture site were undertaken using a titanium bone fixation plate. This clinical report demonstrates that placement of wide-diameter implants in conjunction with bicortical penetration in a severely atrophic edentulous mandible can risk fracture of the mandible., (© 2010 by The American College of Prosthodontists.)

Oral and pharyngeal cancers are among the leading cancer sites. Surgery, radiation, chemotherapy, or combination therapies are common treatment modalities. Radiotherapy and chemotherapy cause significant morbidity and long-term irreversible sequelae in the oral cavity. Surgical resection can be mutilating, disfiguring, and deeply affect self-image. Orofacial defects have unique limitations and challenges for both the surgeon and the maxillofacial prosthodontist. Microvascular surgical techniques and the use of osseointegrated implants improve the rehabilitation potential of the various head and neck defects. This article reviews current treatment modalities of tumor therapy, their consequences, and the restoration of maxillofacial defects.

Statement of Problem: Significant strides in microvascular surgical techniques allow predictable restoration of bony and soft tissue orofacial defects. In combination with prosthetic rehabilitation, varying degrees of improvement in esthetics, speech intelligibility, and swallowing have been noted; however, the relative impact of conventional and implant-supported prostheses on restoration of masticatory function are not known., Purpose: The purpose of this study was to determine whether conventional or implant-supported dental prostheses and current surgical reconstructive procedures restore patients' masticatory function to presurgical levels., Material and Methods: Of the 46 subjects enrolled in this study, 23 (7 edentulous and 16 partially dentate) completed conventional prosthesis (CP) treatment and masticatory evaluation, and of these, 15 (3 edentulous and 12 partially dentate) completed treatment and evaluation with an implant-supported prosthesis (IP). Standardized masticatory performance tests with peanuts and carrots as the test food were made on the defect and nondefect sides. Tests of swallowing threshold performance were made with carrots as the test food. Statistical analysis included repeated-measures analysis of variance (ANOVA) with post hoc Tukey HSD tests (alpha=.05)., Results: Masticatory function at entry was markedly compromised. Further performance declines were noted following surgery (PS) on both the defect and nondefect sides. Restoration with CP and IP produced improvements (significant for defect side only, P<.05) in performance over the PS interval and were not significantly different from performances at entry prior to surgery. In addition, the performance on the defect side with the IP was significantly greater than the performance with the CP (P<.001)., Conclusion: Impairment in masticatory ability remains following free-flap reconstruction prior to prosthetic rehabilitation. Both CP and IP may provide improved masticatory ability, permitting patients to regain the functional level they possessed prior to surgical intervention. The IP may contribute to greater support and stability of the prosthesis, resulting in increased use for mastication and superior performance on the defect side compared to the CP.

Statement of Problem: While surgical restoration of mandibular resections has advanced dramatically with free-flap techniques, oral function and patient perceptions of function, as well as treatment outcomes, often indicate significant impairment., Purpose: This longitudinal prospective study was designed to determine whether conventional prostheses (CP) or implant-supported prostheses (IP) and current surgical reconstructive procedures restore patients' oral functions and quality of life to their status prior to segmental mandibulectomy with immediate fibula free-flap reconstruction. Study design and implementation, characteristics of the study sample, treatment completion rates, and selected presurgical and postsurgical functional and perceptual outcomes are presented., Material and Methods: Forty-six subjects were enrolled. Longitudinal evaluations of medical and dental histories, oromaxillofacial examinations, questionnaires, and sensory and functional tests were planned before and after surgery and after CP and IP treatment. Sample characteristics are described with descriptive statistics and comparisons of subject responses to questionnaire items at entry and postsurgical intervals were made with Fisher exact tests (alpha=.05)., Results: Conventional prostheses were completed in 33 of 46 subjects, and 16 of 33 CP subjects were treated with IP. Reasons for noncompletion of IP were recurrent/metastatic disease (16), refusal of implant therapy (7), lost to follow-up (4), treatment with a reconstruction plate (1), excessive radiation at implant sites (1), and death (1). All 16 recurrences/metastases occurred within 13 months of surgery. Only 3 of the 58 implants placed in 17 participants were considered failures. One failed due to lack of integration 31 weeks following placement, and 2 were buried due to unacceptable positioning for prosthetic restoration during denture fabrication. The remaining 55 implants were successful at final evaluation, ranging from 58 to 123 weeks following implant placement (mean duration=78.9 +/- 16.0 weeks)., Conclusions: While 72% (33/46) of the subjects enrolled were able and willing to complete treatment with CP, only 35% (16/46) completed IP treatment. Careful consideration must be given to selection of the type of prosthetic rehabilitation and the timing of implant placement if an IP is planned.

Purpose: Radiation therapy influence on bone healing around 3 types of endosseous dental implants in dogs was evaluated., Materials and Methods: Implants with 3 different surfaces (A = machined commercially pure titanium screws, B = commercially pure titanium plasma spray-coated cylinders, C = hydroxyapatite [HA] -ceramic coated cylinders) were first implanted unilaterally into the right posterior edentulous mandibles of 7 dogs as nonirradiated controls. After 12 weeks without functional loading and after sequential fluorochrome labeling these implants were retrieved by block dissection. In this same surgery, implants were placed on the contralateral side. Three weeks postimplantation the implant-containing hemimandibles were Cobalt 60 irradiated with the biologic equivalent of 5,000 cGy. Twelve weeks postimplantation and after labeling these irradiated implants were retrieved at sacrifice. On scanning electron, light, and fluorescence microscopic images of undecalcified longitudinal ground sections of the implants with surrounding tissues, percent bone-to-implant contact (% BIC), bone formation, and remodeling were histometrically and subjectively evaluated., Results: Woven bone formation started 1 week after implantation at the implant interfaces on both the nonirradiated and the irradiated sides. Average BICs (total/cortical/spongious bone bed) of 26%/49%/36% for surface A, 46%/48%/64% for surface B, and 81%/83%/78% for surface C were observed. In the irradiated hemimandibles average BICs (total/cortical/spongious bone bed) were reduced to 11%/9%/4% for surface A, 43%/46%/43% for surface B, and 63%/85%/76% for surface C, with increased resorption of peri-implant bone and retarded bone formation after irradiation., Discussion: Reductions of total % BIC in all irradiated implants, though not statistically significant, were significant (P < or = .05) on implant surfaces A and B in the spongious bone bed., Conclusion: Retarded bone formation on surfaces A and B in the spongious bone bed represented a more radiation-sensitive situation at the time of radiation onset compared to advanced bone formation and maturation at surface C.

Statement of Problem: Excessive stress on abutment teeth adjacent to a maxillary resection defect during loading of partial denture obturator frameworks may shorten the life of the teeth., Purpose: The aim of this study was to photoelastically compare the forces exerted on the supporting structures of abutment teeth in 3 differently sized surgical resections with removable partial denture designs used to restore such maxillectomy defects., Material and Methods: Composite photoelastic models were constructed of a human maxilla that had undergone each of 3 maxillectomies: partial, radical, and radical involving the contralateral premaxilla. The abutment teeth included all remaining anterior teeth, the first premolar, and second molar, except the radical maxillectomy, which included the contralateral premaxilla where all remaining teeth were used as abutment teeth. All abutment teeth were restored with complete metal crowns, and removable partial denture frameworks were fabricated. Loading zones were selected according to the resection, and a 10-lb load was applied at each load point. The resulting stresses were observed and recorded photographically in a circular polariscope. The 2 teeth adjacent to the resection were then splinted, and the loading regimens were repeated., Results: Without splinting, loads closer to the defect produced lingual tipping of the teeth adjacent to the resection and a mesial tipping tendency of the second molar. The tipping effects were greatest in the model with the largest resection. Splinting reduced tipping of the teeth adjacent to the resection and produced more uniform stress around these 2 abutment tooth roots for all of the models., Conclusion: The results of this in vitro study suggest that splinting the 2 teeth adjacent to a resection defect improves stress distribution around the roots during loading. This could increase the clinical life of the abutment teeth.

Statement of Problem: Facial defects secondary to the treatment of neoplasms, congenital malformations, and trauma result in multiple functional and psychosocial difficulties. Prosthetic rehabilitation attempts to restore these facial disfigurements and may improve the level of function and self-esteem for these patients. However, a limited number of studies have evaluated the change in perceived quality of life after maxillofacial prosthetic rehabilitation., Purpose: The purpose of this study was to evaluate patients' perceptions of treatment with adhesive-retained and implant-retained facial prostheses and to assess differences in overall satisfaction with these 2 types of treatments., Material and Methods: In this study, a questionnaire with 28 items was administered for evaluation of perceptions of appearance, comfort, fit and irritation, reliability of retention, frequency of wear, ease of placement and removal, level of self-consciousness, and value of treatment. Subjects were categorized into 2 groups: adhesive-retained group (n=16) and implant-retained group (n=19). Comparisons were made for each item in the questionnaire using Fisher exact tests (alpha=.05)., Results: The implant group reported higher positive ratings on all 28 questionnaire items when compared with the adhesive group. Statistically significant (P<.05) differences between the implant and adhesive groups were noted for ease of placement and removal, frequency of wear at home, and quality of retention during various activities, such as home chores and when perspiring or sneezing/coughing., Conclusion: The implant-retained facial prosthesis offers significant enhancement over an adhesive-retained prosthesis with respect to ease of use and retention during a variety of daily activities, resulting in greater use of the prosthesis.

Purpose: An analysis of retrospective data was conducted to establish the survival rates of osseointegrated implants used to retain orbital, nasal, and auricular prostheses over a 14-year period and to recommend guidelines in the restorative treatment of such facial defects., Materials and Methods: Included in this study were all patients who received implant-retained prostheses for auricular, nasal, or orbital defects from 1987 to 2001 in the Maxillofacial Clinics at the UCLA and City of Hope Medical Centers. Data were obtained from patient charts. Two methods were used to determine survival rates: (1) the percentage of the total exposed implants that survived was determined, and (2) life table analysis was used to calculate cumulative survival rates at different time intervals., Results: A total of 207 implants were placed in 72 patients, and 182 implants had been uncovered. During the study period, 35 implants failed to integrate, and the survival rate for all exposed implants was 80%. Auricular implants showed the highest survival rate (95%), and orbital implants showed the lowest survival rate (53%). The life table analysis demonstrated a cumulative 6-year survival rate of 92% for auricular implants and 87% for piriform/nasal implants. In contrast, the survival rate for orbital implants showed a steady downward trend and reached 59% at 66 months., Conclusion: It is possible to achieve high survival rates of implants in the auricular and piriform/nasal sites through careful presurgical and radiographic planning. The less favorable long-term survival of implants in the orbital rim, especially at irradiated sites, requires further study.

The ideal placement of implants is not always possible in partially edentulous patients. The diverse and unique implant positions that occur in clinical practice may be difficult or impossible to restore through the use of conventional abutments. Customized abutments permit the fabrication of aesthetic restorations that correct deficiencies in implant angulation, alignment, and position. These abutments also enhance the soft tissue emergence profile of the restorations and allow the prosthetic margins to be properly positioned in all dimensions. Additional benefits include ease of treatment delivery and comparative expense.

Restorative considerations are critical to the long-term success of fixed implant-supported prostheses, especially in the posterior quadrants of the partially edentulous patient. The parafunctional habit of bruxism must be identified and addressed. The restoration should dictate implant placement. Control of forces directed upon the prosthesis and implants is critical to long-term success. Anatomic limitations to implant placement and surgical procedures to correct these deficiencies must be considered for their impact on the prosthetic restoration. Nonaxial forces or bending moments should be minimized by the use of an adequate number, position and alignment of implants; by control of the occlusion; and by design of the prosthesis. The patient must understand the risks, limitations, costs and time commitments of implant restorations prior to treatment.

Statement of Problem: The success rates of osseointegrated implants used to restore patients who were irradiated for head and neck tumors are influenced by radiation-induced changes in the hard and soft tissues., Purpose: This article examined, by review of the literature, current perspectives on the restoration of irradiated patients using osseointegrated implants., Results: In published reports that investigated both intraoral and extraoral applications, irradiation decreased implant success rates and the amount of reduction was dependent on the location within the craniofacial skeleton. The limited number of implants and patients in these studies precludes definitive conclusions regarding the efficacy of placing implants into irradiated tissues. The implants placed into the irradiated anterior mandible have demonstrated an acceptable implant success rate of 94% to 100% with a minimal risk of osteoradionecrosis. The efficacy of implants in the posterior mandible has not been examined. Implant success rates ranged from 69% to 95% in the irradiated maxilla for intraoral applications. Extraoral applications demonstrated excellent implant success rates in the temporal bone (91% to 100%). The rates in the anterior nasal floor have varied from 50% to 100%. The implant success rates in the frontal bone decreased as the length of the studies increased (96% to 33%). The long-term efficacy of implants in the irradiated frontal bone is poor.

Restorative considerations are critical to the long-term success of fixed implant-supported prostheses, especially in the posterior quadrants of the partially edentulous patient. The parafunctional habit of bruxism must be identified and addressed. The restoration should dictate implant placement. Control of forces directed upon the prosthesis and implants is critical to long-term success. Anatomic limitations to implant placement and surgical procedures to correct these deficiencies must be considered for their impact on the prosthetic restoration. Nonaxial forces or bending moments should be minimized by the use of an adequate number, position and alignment of implants; by control of the occlusion; and by design of the prosthesis. The patient must understand the risks, limitations, costs and time commitments of implant restorations prior to treatment.

Restoration of the edentulous maxilla with implant retained and supported prosthesis is challenging because of inherent anatomic limitations present after the loss of teeth. A fixed-removable prosthesis is one treatment choice for restoration of the edentulous maxilla with implants. This prosthesis meets the requirements for esthetics, phonetics, comfort, and hygiene, as well as favorable biomechanical stress distribution to the implants. This article presents a procedure for fabrication of a fixed-removable prosthesis with a precision milled bar, Hader clip attachments, and a superstructure prosthesis. The criteria for patient selection and the advantages and disadvantages of this prosthesis are discussed.

Twenty patients with microvascular fibula flap reconstruction of oromandibular defects were selected for implant-retained prosthodontic rehabilitation. A total of 71 osseointegrated implants were placed within the grafted fibulas. Four patients had immediate implant placement at the time of their reconstructive surgery, and the remaining 16 patients had implants placed secondarily. One patient received postoperative radiation therapy (5910 cGy) 6 weeks following reconstruction and immediate implant placement. No implants were placed in previously irradiated flaps. A minimum 6-month period of osseointegration was allowed prior to second stage surgery. Fifty-four of the 71 implants were uncovered; 46 of these implants were functional, and 3 were in the process of being restored. Among the 54 implants (15 patients) that were uncovered, only 1 failed to osseointegrate, 2 implants were reburied, and 2 were removed. The follow-up period ranged from 1 to 49 months since second stage surgery. Although a number of prosthodontic designs were used, 11 of the 15 patients were restored with removable overlay prostheses. Only those implants exposed to postoperative radiation demonstrated radiographic bone loss following functional loading.

Purpose: Fabricating a maxillary obturator can be challenging. Placement of implants can have a dramatic effect on the stability and retention of the prosthesis in the edentulous maxillectomy patient. This article provides clinical retrospective analysis of osseointegrated implants used to retain maxillary obturators., Material and Methods: Patient charts and radiographs were reviewed to determine implant status, bone loss patterns, and implant survival rates. Twenty-six patients were included with 102 implants placed, from which there were 19 intact withdrawals (implants lost because of recurrent disease or patient death), five implants with unknown status, 24 implant failures, and 54 functional implants., Results: The overall survival rate for implants in this patient population was 69.2%. The percent implant survival rate was 63.6% for the irradiated group (67.0% before radiation, 50.0% after radiation) and 82.6% for the nonirradiated group. Implants located in anterior sites demonstrated statistically significant differences in annual bone height changes compared with posterior sites., Conclusions: The majority of implant failures (18 of 24) occurred either at stage II surgery or before loading. Implants placed during tumor resection, implants placed within the maxillectomy defects, and implants receiving postoperative radiation demonstrated low survival rates.

Osseointegrated implants can be used to facilitate retention stability and support for facial and intraoral prostheses used to restore head and neck defects. Preliminary studies indicate that in nonirradiated maxillectomy patients the success rates are about 75%. In the reconstructed mandible the results appear to be more favorable--over 90% for implants placed in free nonvascularized bone grafts and over 90% for free revascularized bone grafts. Similar high success rates have been observed for most sites used to support facial prostheses. Success rates for auricular sites exceed 95% and for floor of nose sites success rates exceed 90%. Success rates have been lower (77%) for implants placed in the frontal bone for retention of orbital prostheses. Success rates for irradiated bone sites have been lower and range from 60.4% in the maxilla to 68.6% in facial bone sites. Of greater concern is that most implants placed in irradiated sites are beginning to show signs of impending failure.

This study assesses the success rate of osseous integrated implantation in assisting the prosthetic obturation of maxillectomy defects. Twenty-three patients received a total of 85 osseous integrated implants used for retaining maxillary obturators between 1985 and 1993. Defects include 13 radical maxillectomies, 5 premaxillary resections, 4 subtotal maxillectomies, and 1 soft-palate resection. Thirteen patients (50 implants) received a radiation dose ranging from 5,040 to 7,940 cGy. Implants can be placed at the time of ablation or subsequently. Efforts were made to spare uninvolved segments of the maxilla, especially premaxillary segments and tuberosities, at the time of ablation. Following a 6-month period of integration, implants were uncovered and utilized in prosthetic rehabilitation. Specific implant sites reveal variable success rates, with the anterior maxilla being 86% successful compared with the posterior maxilla being 57% successful. Radiation reduces the success rate from 80% to 55%, although it does not eliminate a patient from being a candidate for implantation. Prosthetic rehabilitation of large maxillary defects can be greatly facilitated with the use of osseous integrated implants in the remaining midfacial skeleton.

The acquisition, processing, and use of three-dimensional (3D) imaging provide new insights into normal and abnormal craniofacial anatomy. In this article, characteristics of CT and MRI scanning are reviewed along with the methods used to delineate tissues and produce 3D patient displays, including contouring, shaded surface, and volumetric processing. The use of 3D model fabrication for surgical planning is discussed with examples of the production of a custom CT-based auricle model and the use of rapid prototyping technology to create models for custom alloplastic implant surgery. The review concludes with some speculation about the future of 3D medical imaging as it will influence surgical training and practice over the coming decades.

From 1987 to 1990, 28 patients were treated with titanium implants (Brånemark flange fixtures) in the craniofacial area for the support of craniofacial prosthesis or anchorage of bone-conduction hearing aids in the Orofacial Implant Center at the University of California, Los Angeles (UCLA). A total of 88 implants were placed, of which 22 were placed in previously irradiated areas. Twenty-three of the implants were placed in the orbital area, 37 in the mastoid area, 20 in the nasal area, and eight in various other craniofacial regions. Seven implants were lost in four different patients. The proper location and positioning of implants in specific areas of the craniofacial regions, as well as soft-tissue complications and management, are discussed.

Osseointegrated implants have been in widespread use for more than 10 years. During this time, the design and use of implant-supported and implant-retained dental restorations have undergone steady change. This paper discusses this evolution and defines current trends in this exciting new discipline.

Three different types of commercially available dental implants (Nobelpharma, IMZ, and Integral) were implanted in the edentulous mandibles of seven adult mongrel dogs. Twenty-one implants were harvested with block sections after 12 weeks and embedded in polymethyl methacrylate resin. Undecalcified sections were prepared with the sectioning-grinding technique. The percentage of bone contacting the implant surface was measured with a self-designed histomorphometry method using a millimeter grid in a stereomicroscope. The results demonstrated a significantly higher percentage of bone along the hydroxyapatite-coated implant than that seen with the titanium-surfaced implant types.

Complete dentures were fabricated for 88 patients following completion of cancericidal doses of radiation therapy to the head and neck regions. All were followed for at least 6 months after delivery. All patients received dentures resting within the radiation field. Three patients developed osteoradionecroses directly attributable to their dentures. These three had been dentulous prior to therapy and had either pre- or posttreatment extractions. Of the 58 patients who had been edentulous prior to therapy, none developed osteoradionecrosis. Five patients developed soft tissue necroses secondary to the use of dentures.

There is an increasing number of patients receiving radiation therapy for oral malignancies. In many malignant tumors, radiation is often the treatment of choice, while in others it may be used in conjunction with surgery or chemotherapy. There are inherent dental and oral problems associated with radiation therapy. It is the purpose of this paper to deal briefly with the physical principles and the biological basis of radiation therapy. In addition, the specific radiation effects on oral mucous membranes, taste buds, salivary glands, bone, the periodontium and teeth will be discussed. Radiation complications in edentulous patients, and in particular the problems of wearing dentures in such patients will be evaluated. An approach to the problem of dental extractions and other dental treatments in the pre- and post-irradiated patient is suggested.

Studies were done with 120 patients submitting to preradiation dental extraction within the radiation treatment volume. Bone necroses developed at the extraction sites in 17 patients (14.1%). The risk of bone necrosis in these patients is primarily dependent upon the size of the radiation treatment volume, radiation dose to mandibular bone, and healing time for the extraction wounds. Of the 13 mandibular bone necroses occurring at preradiation extraction sites, only two have not responded favorably to conservative management. Our data indicates that a policy of selected tooth removal, before radiation treatment, will minimize the risk of osteoradionecrosis. Mandibular molars with advanced chronic periodontal bone loss, residing within the proposed radiation field should be considered for removal before commencement of radiation treatment.

This report outlines our experiences involving 72 episodes of postradiation dental extraction over an 11-year period. Bone exposures of 3 months or longer developed following 16 of the 72 postradiation extraction episodes (22%). The necrosis rate in the mandible was 29% (13 of 45) and in the maxilla was 11% (3 of 27). The risk of bone necrosis increased when the dose to bone exceeded 6,500 rad, and when 75% or more of the body of the mandible was within the radiation treatment volume. Five of the 13 mandibular bone necroses precipitated by postradiation extractions eventually required radical resection of the affected portion of the mandible. The remaining eight mandibular episodes healed with conservative measures. When possible, given the two above conditions, root canal therapy rather than dental extraction should be employed to resolve mandibular dental infection within the radiation field after radiotherapy.

A review of the methods of cranioplasty has been presented. A method of prefabrication of an alloplastic cranial implant has been described as well as a review of 40 patients with whom this technique was used.

Improper implant angulation is one of the most difficult problems to overcome in the fabrication of implant-supported and implant-retained restorations. Several techniques using the "UCLA" abutment have been developed to solve these problems. The creation of large screw-access holes for moderate angulation and the fabrication of telescopic copings and overlay castings for severe angulation problems are discussed.

This is the concluding portion of a two-part series dealing with the effects and manifestations in the oral cavity of radiation therapy of head and neck tumors. Preradiation and postradiation extractions in dentulous patients, as well as dental maintenance of such patients (including fluoride treatments follow-up, and restorative care), are discussed. Guidelines for the dental management of edentulous patients are also presented at length (this section covers risk of bone necrosis, soft liners, timing of denture placement, dentures and preexisting bone necrosis, soft-tissue necrosis and dentures, morbidity, and prosthodontic procedures). The article concludes with a brief discussion of osteoradionecrosis and soft-tissue necrosis.

Inferior border rib grafting appears to be a useful procedure in providing bony augmentation for severely atrophic edentulous mandibles. Major advantages to the prosthodontic patient are that (1) remodeling and changes in the denture-bearing surfaces are minimal following surgery, (2) the interocclusal space is unaltered, (3) in nonunion body fractures occurring in severely atrophic mandibles, the ribs applied to the inferior-buccal and inferior-lingual aspects of the mandible hold the fragments in a much more favorable position, thus preventing superior elevation of the posterior segment and inferior displacement of the anterior segment, and (4) resorption rates seem acceptable. The patient should be informed of possible consequences. As with all preprosthetic special procedures, a psychosocial analysis may also be indicated.

This report includes 14 patients with rhinocerebral mucormycosis treated at the UCLA Medical Center since 1970. This disease has an extremely high mortality and morbidity. It is of interest to dentists because of the common presenting symptoms of periorbital cellulitis and sinusitis and the occasional presenting symptoms of dental pain or subperiosteal swelling. It is of further interest because of the intraoral and extraoral midfacial defects that result from disease extension and the necessary surgical débridement. The resultant facial and oral defects are far more difficult to restore than similar defects secondary to resection of head and neck neoplasms.

A definition and classification of midfacial defects has been presented with a systematic approach to the prosthetic restoration of these defects. Patient factors, prognostic and diagnostic considerations, clinical procedures, fabrication, materials, and retention have been discussed. Patients with complex orofacial defects can be provided with prosthodontic treatment that results in an acceptable appearance and function consistent with the deficits encountered (Figs. 14 and 15).

This is the first article in a two-part series dealing with the effects and manifestations in the oral cavity of radiation therapy of head and neck tumors. In this section, oral mucous membranes, taste buds, edema and trismus, diet, salivary glands, bone, periodontium, teeth, and composition of oral flora are discussed. Dental management of the dentulous patient is then approached; criteria for preradiation extraction are delineated. In the next issue of Head & Neck Surgery, the final article in this series will discuss preradiation and postradiation extractions and will elaborate on the dental management (fluoride treatments, follow-up, and restorative care) of the dentulous patient. Dental management of the edentulous patient will also be presented.

Restoration of facial symmetry is the goal in rehabilitation of an orbit disfigured by trauma or tumor extirpation. Successful rehabilitation may require replacement of repositioning of the orbital walls and/or construction of a complex orbital prosthesis. Preoperative communication among the head and neck surgeon, ophthalmologist, and maxillofacial prosthodontist is essential.

Facial deformity secondary to Crouzon disease may include exophthalmos and midfacial hypoplasia. If there is no dental malocclusion, treatment may consist of transantral orbital decompression and infraorbital augmentation with custom-made Silastic implants.