tion was found between CD34 density and youngerpatient age (p � 0.06). Multiple authors have suggestedthat giant cell tumors in pediatric patients have moreaggressive clinical behavior and a proliferative vascularphase may contribute to this pattern. The successful useof antiangiogenic therapy (in particular, interferon alpha-2a) in the treatment of aggressive giant cell tumors alsosuggests the importance of the vascular component. Thepurpose of this study is to compare the CD34 expressionin both aggressive and non-aggressive giant cell tumorsof the jaws and to determine whether vascular densitymay prove an important marker of biologic behavior.

Materials and Methods: Patients treated for giant celllesions of the jaws between 1995 and the present wereidentified through the Massachusetts General HospitalGiant Cell Patient Registry. The lesions were character-ized as aggressive or non-aggressive based on previouslypublished criteria. Paraffin-embedded, formalin-fixed his-tologic blocks were sought for all patients. A total of 23aggressive samples and 8 non-aggressive samples wereobtained. The specimens were sectioned at 5 micronsand processed for immunohistochemical evaluation. Amodified Avidin-biotin-peroxidase complex techniquewas employed utilizing a 1:35 dilution of mouse mono-clonal anti-CD34 antibody (DakoCytomation, CA). A pos-itive reaction was indicated by red-colored precipitate atthe antigen site. The intensity of staining was quantifiedin three different areas of each sample using the Bio-quant software image analyzer (BIOQUANT Image Anal-ysis Corporation, Nashville, TN) to yield an average mea-surement.

Method of Data Analysis: The density of CD34 stainingwas calculated as the sum of the area of each of thetarget vessels divided by the total area of the image X100. Statistical comparison between the 2 groups wasaccomplished using bivariate analysis.

Results: Twenty-three patients had tumors classified asaggressive. There were 17 females and 6 males withaverage age of 20 years (range 5-83). Sixteen tumorswere mandibular, 7 were maxillary. The average CD34density of this group was 5.4% (plus/minus 3.5%). Eightpatients had tumors classified as non-aggressive. Therewere 6 females and 2 males with an average age of 37years (range 8-74). The average CD34 density of thisgroup was 2.5% (plus/minus 0.8%). The CD34 densitymeasurements of these 2 groups were statistically differ-ent (p less than 0.001).

Conclusion: Our data concur with previous studiesdemonstrating both a female and mandibular predilec-tion of giant cell tumors of the jaws. The age disparitybetween aggressive lesions (20 years) and non-aggres-sive lesions (37 years) supports the notion that tumors inyounger patients tend to behave more aggressively. Therole of tumor vascularity on biological behavior remainsto be elucidated. The response of many aggressive giantcell tumors to antiangiogenic therapy supports the hy-

pothesis that they are vascular proliferative lesions. Thesignificant difference demonstrated in vascular densitybetween the aggressive and non-aggressive samples sug-gests that the two variants may be distinguishable at thetime of biopsy. Vascular density might be helpful inidentifying suitable candidates for antiangiogenic ther-apy as well as determining response to such therapy.Future studies will focus on increasing the sample size ofboth groups as well as comparing vascular density of theaggressive jaw lesions to giant cell tumors of the longbones.

References

Chuong R, Kaban LB, Kozakewich H, et al: Giant cell lesions of thethe jaws: A clinicopathologic study. J Oral Maxillofac Surg 44:708,1986

Kaban LB, Troulis MJ, Ebb D, et al: Antiangiogenic therapy withinterferon alpha for

Kaban LB: Aggressive jaw tumors in children. Oral Maxillofac ClinNorth Am

Funding Source: Oral and Maxillofacial Surgery Education and Re-search Fund (Massachusetts General Hospital), Office of EnrichmentPrograms, Harvard Medical School

POSTER 36Comparison of Traditional Radiographyand 3D Cone-Beam CT in Management ofImpacted CaninesEric Haney, DDS, UCSF, Dept of OMFS, Attn: Dr JaniceLee, 521 Parnassus Ave. C522, San Francisco, CA94143-0440 (Huang J; Pogrel MA; Lee JS)

Statement of the Problem: Cone-beam computed to-mography (CBCT) utilizes conventional x-ray technologyand computerized volumetric reconstruction to providehigh-resolution 3-dimensional (3D) images with reducedradiation dosage compared to conventional CT. Thisadvanced modality may provide valuable diagnostic in-formation. However, there is very little research to de-termine whether 3D imaging provides significantly moreinformation than traditional radiographs whereby diag-nosis and treatment planning may be affected. This is aprospective study comparing the differences in diagno-sis and treatment of impacted maxillary canines usingtraditional 2D planar radiographs versus 3D volumetricimages generated from CBCT data.

Materials and Methods: Twenty-five consecutive im-pacted maxillary canines were identified from the pa-tients seeking orthodontic treatment at UCSF Division ofOrthodontics and enrolled in this study. IRB approvaland participant consent were received. For each case,two sets of radiographic information were obtained. Thefirst set of traditional radiographs included a panoramic,occlusal, and two periapical radiographs. The second setwas composed of 3D volumetric dentition images ob-

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tained from a CBCT scan. Thus, there were 50 sets ofimages in total for review. A questionnaire was devel-oped that reviewed the position of the impacted canine,the treatment for orthodontic/vector movements, andthe planned surgical approach. Specific questions thatwere answered included: 1) the location of the cusp tip,2) presence or absence of root resorption, 3) the ortho-dontic or surgical treatment plan, and 4) the subjectiveconfidence level of each diagnosis and treatment planusing the different diagnostic images, including the needfor further images. The same questionnaire was used forboth imaging modalities.

Of the seven UCSF diagnosticians who participated inthis study, four were orthodontic and three were oral &maxillofacial surgery faculty. Three of the seven judgeswere senior faculty with more than 10 yrs of clinicalexperience, while four were categorized as junior fac-ulty. Upon reviewing the case, each clinician completeda questionnaire for the impacted canine and radio-graphic modality. The patient data sets were presentedin random order, and five canine cases were randomlyrepeated to evaluate intra-examiner reliability.

Method of Data Analysis: Data will be analyzed usingMcNemar Test, Fisher Exact Test, paired t-test. A p-valueof �0.05 will be considered statistically significant.

Results: Upon comparing the responses between thetwo types of images for the same impacted tooth, thejudges did alter their decision regarding localization: therewas an average of 29% difference in determining the mesial-distal, labial-palatal, and vertical position. In the diagnosis ofroot resorption of adjacent teeth, there was a 36% differ-ence between the two radiographic modalities. The vectorfor recovery or orthodontic treatment plan changed in34.3% of the cases and of all the teeth examined by theorthodontists, 53% of the teeth treatment planned for ex-traction with traditional radiographs were selected for re-covery after viewing the CBCT images (McNemar Test, �2� 4.45, p � 0.035). The surgical decision regarding thelocation of initial surgical access changed 16% of the timeand correlated directly with the change in labial-palatalposition of the canine. For 34% of traditional images, addi-tional images were requested compared to 19% of CBCTimages (McNemar Test, p � 0.002). Senior practitionerswere more likely to request additional images with the 2Dmodality while the junior practitioners requested additionalimages for both modalities. Confidence of the accuracy ofdiagnosis and treatment plan was statistically higher forCBCT images for both senior and junior practitioners(paired t-test, p � 0.001).

Conclusion: These results suggest that the 3D imagesfrom the CBCT of the impacted canines in the maxillacan provide additional information which could result ina clinician modifying their diagnosis and treatment strat-egies. This would include significant treatment planchanges such as the need for extraction versus orthodon-tic recovery and the surgical access.

References

Scarfe WC, Farman AG, Sukovic P: Clinical applications of cone-beam computed tomography in dental practice. J Can Dent Assoc72(1):75, 2006

Nakajima A, et al: Two- and three-dimensional orthodontic imagingusing limited cone beam-computed tomography. Angle Orthod 75(6):895, 2005

Funding Source: UCSF Academic Senate Grant

POSTER 37Sialoendoscopy and Sialography ModernApproach for Salivary GlandObstructionsOscar Hasson, DDS, Yossef Sapir Street 1/3, RamatGan, 52622, Israel

Statement of the Problem: Obstructions of salivaryglands are a common problem that affects many patients.Sialolithiasis is the common obstruction yet kinks andstenosis of salivary ducts may also be present. Until theintroduction of sialoendoscopy, symptomatic patientssuffering from obstructions located in the posterior por-tion of the duct (close to the gland) were treated withremoval of the gland with its known complications. Theendoscopic techniques permit reaching and removing,in most of the cases, obstruction in deeper regions of theduct. Also the introduction of sialoendoscopy broughtback the sialography as an important pre-sialoendoscopydiagnostic exam. The purpose of this paper is to presentsialoendoscopy and sialography as state of the art treat-ment for diagnosis and treatment of salivary gland ob-structions.

Materials and Methods: This study was a retrospectiveevaluation of thirty consecutive patients suffering of sali-vary gland obstruction (20 parotid glands and ten subman-dibular glands). All patients presented with swelling in theinvolved gland and purulent or thick discharge from thesalivary duct. All patients were initially treated with antibi-otics. More severe cases were admited to the hospital andtreated with intravenous antibiotics. Following the acutephase all patients had a diagnostic sialography exam.Twenty were submited to sialoendoscopy to treat theirobstructions. The sialoendoscopy procedures were per-formed under local anesthesia and intravenous sedation.Karl Storz Germany, 1 mm endoscope was usedin all patients. The technique consisted of dilating salivaryduct and inserting first the diagnostic 1.3 sheat, for diagno-sis and location of intra-duct pathologies followed by theinsertion of the 2.3 working channel sheat to permit inser-tion of specially designed instruments (graspers and bas-kets) and balloons for removal of sialolithiasis and openingof duct obstructions.

Method of Data Analysis: Retrospective analysis.Results: Sialography was performed in all patients

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