George C. Bohle

Osteonecrosis of the maxilla and mandible in patients with advanced cancer treated with bisphosphonate therapy

Cases of osteonecrosis of the jaw (ONJ) have been reported with an increasing frequency over the past 5 years. ONJ is most often identified in patients with cancer who are receiving intravenous bisphosphonate (IVBP) therapy, but it has also been diagnosed in patients receiving oral bisphosphonates for nonmalignant conditions. To further categorize risk factors associated with ONJ and potential clinical outcomes of this condition, we performed a retrospective study of patients with metastatic bone disease treated with intravenous bisphosphonates who have been evaluated by the Memorial Sloan-Kettering Cancer Center Dental Service between January 1, 1996 and January 31, 2006. We identified 310 patients who met these criteria. Twenty-eight patients were identified as having ONJ at presentation to the Dental Service and an additional 7 patients were subsequently diagnosed with ONJ. Statistically significant factors associated with increased likelihood of ONJ included type of cancer, duration of bisphosphonate therapy, sequential IVBP treatment with pamidronate followed by zoledronic acid, comorbid osteoarthritis or rheumatoid arthritis, and benign hematologic conditions. Our data do not support corticosteroid use or oral health as a predictor of risk for ONJ. Clinical outcomes of patients with ONJ were variable with 11 patients demonstrating improvement or healing with conservative management. Our ONJ experience is presented here.

Intravenous bisphosphonate–related osteonecrosis of the jaw: Long-term follow-up of 109 patients

OBJECTIVE We report long-term follow-up of patients with intravenous bisphosphonate-related osteonecrosis of the jaw (BRONJ). STUDY DESIGN Medical and dental histories, including type and duration of bisphosphonate treatment and comorbidities, were analyzed and compared with clinical course of 109 patients with BRONJ at Memorial Sloan-Kettering Cancer Center Dental Service. RESULTS Median onset of BRONJ in months was 21 (zoledronic acid), 30 (pamidronate), and 36 (pamidronate plus zoledronic acid), with a significant difference between the pamidronate plus zoledronic acid and zoledronic acid groups (P = .01; Kruskal-Wallis). The median number of doses for BRONJ onset was significantly less with zoledronic acid (n = 18) than pamidronte plus zoledronic acid (n = 36; P = .001), but not pamidronate alone (n = 29). An association between diabetes (P = .05), decayed-missing-filled teeth (P = .02), and smoking (P = .03) and progression of BRONJ was identified through χ(2) test. CONCLUSIONS This long-term follow-up of BRONJ cases enhances the literature and contributes to the knowledge of BRONJ clinical course.

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

Restoration of speech after surgical resection for oropharyngeal cancer traditionally includes maxillofacial prosthetic intervention. Relatively few publications with objective speech outcomes exist. The purpose of this study was to evaluate speech outcome relative to the size of the surgical defect, the type of speech prosthesis, and the height and position of the speech bulb in relation to the posterior pharyngeal wall in the nasopharynx.

Molecular profiling of oral microbiota in jawbone samples of bisphosphonate-related osteonecrosis of the jaw

Oral Diseases (2012) 18, 602–612 Objective:  Infection has been hypothesized as a contributing factor to bisphosphonate (BP)‐related osteonecrosis of the jaw (BRONJ). The objective of this study was to determine the bacterial colonization of jawbone and identify the bacterial phylotypes associated with BRONJ. Materials and methods:  Culture‐independent 16S rRNA gene‐based molecular techniques were used to determine and compare the total bacterial diversity in bone samples collected from 12 patients with cancer (six, BRONJ with history of BP; six, controls without BRONJ, no history of BP but have infection). Results:  Denaturing gradient gel electrophoresis profile and Dice coefficient displayed a statistically significant clustering of profiles, indicating different bacterial population in BRONJ subjects and control. The top three genera ranked among the BRONJ group were Streptococcus (29%), Eubacterium (9%), and Pseudoramibacter (8%), while in the control group were Parvimonas (17%), Streptococcus (15%), and Fusobacterium (15%). H&E sections of BRONJ bone revealed layers of bacteria along the surfaces and often are packed into the scalloped edges of the bone. Conclusion:  This study using limited sample size indicated that the jawbone associated with BRONJ was heavily colonized by specific oral bacteria and there were apparent differences between the microbiota of BRONJ and controls.

Dosimetric distribution to the tooth-bearing regions of the mandible following intensity-modulated radiation therapy for base of tongue cancer

OBJECTIVES Osteoradionecrosis is a significant complication following head and neck radiotherapy. The purpose of this study was to determine the intensity-modulated radiation therapy (IMRT) dosages delivered to the tooth-bearing regions of the mandible. STUDY DESIGN A total of 28 patients with base of tongue cancer with the following stages: T1-2/N2-3 (n = 10), T3-4/N2-3 (n = 10), and T1-4/N0 (n = 8), treated with IMRT, were included. Average mean and maximum doses were calculated for the anterior, premolar, and molar regions. RESULTS Lower doses were seen in anterior bone with smaller tumors. Large tumors, regardless of laterality, resulted in high doses to the entire mandible, with anterior bone receiving more than 6000 cGy. CONCLUSIONS Tumor size is important in preradiation dental treatment planning. This information is important in planning pre- and postradiation dental extractions. Dosimetric analyses correlating mean and maximum point dose with clinical presentation and outcomes are needed to determine the best predictor of osteoradionecrosis risk.

Significant reduction in dental cone beam computed tomography (CBCT) eye dose through the use of leaded glasses.

OBJECTIVE In light of the increased recognition of the potential for lens opacification after low-dose radiation exposures, we investigated the effect of leaded eyeglasses worn during dental cone-beam computerized tomography (CBCT) procedures on the radiation absorbed dose to the eye and suggest simple methods to reduce risk of radiation cataract development. STUDY DESIGN Dose measurements were conducted with the use of 3 anthropomorphic phantoms: male (Alderson radiation therapy phantom), female (CIRS), and juvenile male (CIRS). All exposures were performed on the same dental CBCT machine (Imtec, Ardmore, OK) using 2 different scanning techniques but with identical machine parameters (120 kVp, 3.8 mA, 7.8 s). Scans were performed with and without leaded glasses and repeated 3 times. All measurements were recorded using calibrated thermoluminescent dosimeters and optical luminescent dosimetry. RESULTS Leaded glasses worn by adult and pediatric patients during CBCT scans may reduce radiation dose to the lens of the eye by as much as 67% (from 0.135 ± 0.004 mGy to 0.044 ± 0.002 mGy in pediatric patients). CONCLUSIONS Leaded glasses do not appear to have a deleterious effect on the image quality in the area of clinical significance for dental imaging.

Immediate Obturator Stabilization Using Mini Dental Implants

Edentulous patients with maxillary defects face a more challenging oral rehabilitation process than dentate patients. With the use of mini dental implants (MDIs), it is now possible to immediately increase obturator retention and stability. Implant patients can have a retentive obturator that enhances the overall efficacy of the prosthesis both in comfort and function.

Fistula formation after postoperative radiation treatment for paranasal sinus cancer.

Postoperative radiation is frequently used in the treatment paradigm for paranasal sinus tumors. The development of 3-dimensional conformal radiation treatment and intensity modulated radiotherapy (IMRT) has facilitated the delivery of high doses required for local control of these lesions while simultaneously decreasing toxicity. At Memorial Sloan-Kettering Cancer Center, a radiation dose of 70 Gy is routinely prescribed to gross tumor, and 59.4 Gy is prescribed to a clinical target volume at high risk for subclinical disease and 54 Gy is delivered to a clinical target volume at low risk for subclinical disease. Fistula formation can occur with the delivery of postoperative radiation treatment despite the use of IMRT. Prosthesis fabrication can be used in the short-term management of this unfortunate complication with an acceptable cosmetic result. Patients should be aware of this potential toxicity, which can develop in spite of appropriate management and acceptable dosimetry. Nonetheless, combined modality therapy is recommended for aggressive treatment of paranasal sinus tumors to inhibit local progression. This report describes the clinical scenario and management of the rare incidence of fistula formation after radiation for paranasal sinus malignancy.

A technique for fabricating the dental positioning component for stereotactic radiotherapy

Stereotactic radiosurgery has been successful in treating small brain tumors with high accuracy.1 The treatment modality refers to the delivery of a large dose of radiation administered to a small, precisely defined target. This is achieved by using multiple, nonparallel radiation beams that converge on the target lesion and necessitates precise delineation of the lesion. The most common illnesses treated with this method include: acoustic neuroma, brain metastasis, meningioma, pituitary adenoma, craniopharyngioma, chordoma, hemangioblastoma, arteriovenous malformation (AVM), and glioma/glioblastoma. Both photon beams and charged particle beams are used for treatment with the gamma knife and linear accelerator, which are 2 of the most popular instruments for photon beam radiosurgery.1,2 Predictable, repeatable immobilization of the patient is paramount to achieve a high degree of successful tumor ablation.1-3 Several methods for fabricating the dental component of the stereotactic appliance have been described.4,5 The methods range from stone casts being fabricated and placed into autopolymerizing acrylic resin directly on the stereotactic tray, to using modeling plastic impression compound, vinyl polysiloxane, or polyether to directly affix the tray to the maxillary arch. While placing impressions directly from the mouth into the stereotactic tray is efficient and cost-effective, the material could pull from the tray with repeated insertion and removal, or could lock intraorally around undercuts associated with fixed partial dentures or bony prominences. The indirect method of embedding a stone cast into acrylic resin attached directly to the stereotactic tray provides a rigid device; however, relief around the undercuts of the teeth and soft tissue may result in an imprecise fit. The laboratory time needed to fabricate a positioning device with this method is also greater than if using the technique described in this study. The technique described is straightforward and provides a precise, comfortable positioning device which requires little chair time for insertion. The resilient lining of the dual laminate intimately engages the teeth and soft tissues while allowing relief from most routine undercuts. The firm acrylic resin outer shell provides a stable base to attach to the stereotactic tray and will not distort with repeated use. Using this technique to fabricate the positioning appliance adds the negligible cost of the vacuum-forming material but, overall, saves fabrication and insertion time. Patients typically report to the Memorial Sloan-Kettering Cancer Center dental service on the day of the consult with the radiation oncologist for the impression and then return for insertion 30 minutes prior to the simulation appointment. This article describes a technique for fabricating a stereotactic positioning appliance using a vacuum-forming material and acrylic resin to provide an efficient, precise, and comfortable device.