Poster 9

Scientific Poster Session References Todd R, Wong DTW: DNA hybridization arrays for gene expression analysis of human oral cancer. J Dent Res 81:89, 2002 Deveraux Q, Reed J: IAP family proteins–suppressors of apoptosis. Genes Dev 13:239, 1999 Funding Source: OMS Department. Supported by NIH grants R29 DE11983 (R.T.), P01 DE12647(R.T.), K02 00456 (R.T.), and R01 DE11430 (R.T.) as well as a Research Support Grant from the Oral and Maxillofacial Surgery Foundation (H.O./R.T.) and a Milton Grant from Harvard University (R.T.).

POSTER 8 Potential Complications During Alveolar Distraction Osteogenesis

dictable technique with a success rate close to 92%. Vertical bone defects can be treated using osteodistraction. Minor complications can occur without failure of the procedure and a close follow-up and opportune intervention is necessary in those cases. References Chin M, Toth BA: Distraction osteogenesis in maxillofacial surgery using internal devices. J Oral Maxillofac Surg 54:45, 1996 Millesi-Schobel GA, et al: The L-shaped osteotomy for vertical callus distraction in the molar region of the mandible: A technical note. J Craniomaxillofac Surg 28:176, 2000 Funding Source: Unicamp–Brazilian Government Grant.

Renato Mazzonetto, DDS, PhD, Rua Padre Jose Conceicao Meireles, #60, Piracicaba, Sao Paulo 13418.405 Brazil (Torezan JF)

POSTER 9

Statement of the Problem: Alveolar atrophy has been a major problem in achieving successful rehabilitation with dental implants. Distraction osteogenesis has been clinically applied to augment the alveolar ridge vertically since 1996. Purpose: The aim of this study is to evaluate the clinical results of alveolar distraction technique and its potential problems during the treatment. Patients and Methods: The subjects comprised 50 patients who underwent vertical bone augmentation using an alveolar distraction device in anterior maxilla and atrophic mandible. The follow-up schedule for all patients consisted of regular appointments at 1, 7, 14, 30, 60, and 90 days after surgery. At 90 days, the device was removed and implants were placed. Clinical evaluation involved notation of any abnormal problem. The problems were classified in 2 groups: Minor complications that do not compromise the success overall (swelling, minor infection, dehiscence or exposure of device, tipping of transport segment, temporary lost of sensibility) and major complications with failure of technique (device fracture, scar tissue formation, fracture or resorption of transport disk, and permanent loss of sensibility). For radiographic evaluation, orthopantomograms were taken at 7, 30, 60, and 90 days. The radiographs were analyzed for any visual changes in osteotomy fragments, resorptive changes in osteotomy fragments, and union of the osteotomy segments. Results: Among minor complications we found 4 cases of exposure of device (8%), 4 cases of abnormal swelling in mandible (8%), 1 case of temporary loss of sensibility (2%), and 12 cases of tipping of the transport disk (24%), treated by local anesthesia and positioning the segment manually back to its ideal location. Major complications were found in 4 cases (8%), when we observed fracture or resorption of transport disk. Conclusions: Alveolar distraction osteogenesis is a pre-

Roger W. Moreira, DDS, PhD, 3501 Terrace Street, Suite G-32, Pittsburgh, PA 15261 (Costello BJ; Ochs MW; Hart P; Michalec M; Hart TC)

AAOMS • 2003

Aquaporin Expression in Dental Follicle and Odontogenic Keratocysts

The aquaporins (AQP) are a family of membrane channel proteins that function as selective pores through which water crosses the plasma membranes of many tissues and cell types. Eleven members of this transporter family, designated AQP0 to AQP10, have been cloned in humans. To understand the etiology of OKC development, we studied AQP expression in dental follicles (DF) and odontogenic keratocysts (OKCs). Mutations of the PTCH gene that encode a transmembrane protein have been identified in syndromic and isolated cases of OKC, but the impetus for development of cystic lesions is not understood. Raised osmolalities may be important in cystic development. We evaluated AQP expression by RT-PCR. RNA was isolated from 8 DF and from 3 OKCs using Purescript reagent and cDNA was synthesized with the Advantage RT-for-PCR Kit. Oligonucleotide primers were designed to amplify specific AQPs and distinguish genomic and cDNA products. RT-PCR amplification products were purified and sequence verified using Big Dye Terminator (ABI) chemistry. All experiments were performed in duplicate. Control tissues were used to demonstrate that absence of RT-PCR products in the OKC and DF samples were not simply due to amplification failure. Results of RT-PCR and sequence verification demonstrate that AQPs are differentially expressed in DF and OKCs. AQPs 1, 9, and 10 are expressed in DF, while AQPs 1, 3, 9, and 10 are expressed in OKCs. Our evaluation of expression patterns of the aquaporin gene family was driven by the hypothesis that cystic development involves cellular control of ion concentrations in the epithelial lining and that this regulation is, in part, controlled by regulated water transport. The generality of AQP expression in skin from different 85

Scientific Poster Session sites is unknown, and 8 AQPs are reported to be expressed in various tissues of the GI tract, including AQPs 1, 3, 4, 5, 7, 8, 9, and 10. While the recently identified AQP10 is known to be expressed in keratinized gingiva, the specific combinations of AQP expression found in DF and OKCs are not previously reported for skin, suggesting the DF tissues may be developmentally unique. AQP3 is functionally heterogeneous and possesses water and solute permeation mechanisms. The differential expression of AQP3 may be important in OKC development and may help understand their etiology. References Wang W, Hart PS, Piesco NP, et al: Aquaporin expressions in developing human teeth and selected orofacial tissues. Calcif Tissue Int 1, 2003 Horster M: Embryonic epithelial membrane transporters. Am J Physiol 279:F982, 2000

POSTER 10 Immunolocalization of Opioid Receptors in Primate Trigeminal Ganglion Stephen B. Milam, DDS, PhD, University of Texas Health Science Center, Dept. of OMS, San Antonio, TX (Tobler J; Cui Y; Zardeneta G) Opioids have been administered peripherally to regulate pain and neurogenic inflammation, presumably by action via opioid receptors expressed by primary trigeminal ganglion neurons. However, to date, opioid receptor expression by trigeminal ganglion neurons has not been fully characterized. The aim of this study was to determine the percentage of neurons expressing either of the opioid receptors (MOR, KOR or DOR) in trigeminal ganglia (tgg). Methods: Fresh trigeminal ganglia were harvested from baboons (P. cynecephalus) and either frozen in OCT or used to establish primary neuronal cultures for 7 days. Cross-section slices (20 micromolar) from OCT embedded tgg were used for immunohistochemistry using specific antibodies against the opioids (Biodesign). Species-specific secondary antibodies tagged with a peroxidase were employed and the standard DAB colorimetric substrate used. Percentage of neurons staining positive for these receptors were counted independently by 2 examiners using light microscopy. Dispersed tgg were grown in media supplemented with nerve growth factor (10 nanomolar) containing mitotic inhibitors to establish primary neuron cultures. Maximum neuronal outgrowth was observed after 7days in culture. These cultured tgg neurons were used to verify opioid receptor expression using standard western blot analyses. Neurons were lysed in an SDS-containing solution, and analyzed by SDS-PAGE followed by western blot using the same antibody scheme as above. Opioid receptors were visualized by ECL. 86

Results: The average percentage of tgg neurons containing MOR, KOR, or DOR were found to be 34%, 27%, and 24%, respectively. Cultured tgg neurons were found to express all 3 of the opioid receptors, although the percentage of cultured tgg neurons expressing these was not determined by this method. Conclusion: A significant percentage of neurons (24% to 34%) from adult primate trigeminal ganglion were found to express MOR, KOR, or DOR in vivo. These opiate receptors also were identified in tgg cultures by western blot. This study provides evidence that MOR, KOR, and DOR are expressed by tgg neurons. Future studies will be required to characterize specific trigeminal ganglion neural responses to peripherally-administered opioid receptor subtype-selective opioid agonists. References Hargreaves KM, Keatin K, Cathers S, et al: Analgesic effects of morphine after PDL injection in endodontic patients. J Dent Res 70: 445, 1991 List T, Tegelberg A, Haraldson T, et al: Intra-articular morphine as analgesic in temporomandibular joint arthralgia/osteoarthritis. Pain 94: 275, 2001 Funding Source: UTHSCSA PREF award.

POSTER 11 Effects of Radiation on Primary Human Oral Mucosal Keratinocytes Takayoshi Tobita, DDS, PhD, University of Michigan, Dept. of OMS, Ann Arbor, MI 48109-0018 (Izumi K; Feinberg SE) Purpose: Oral mucositis is a serious side effect for patients undergoing radiotherapy for head and neck tumors. It consists of 4 stages: 1) an initial inflammatory/ vascular phase, 2) an epithelial phase, 3) an ulcerative/ bacteriological phase, and 4) a healing phase. This investigation is a preliminary report in the development of an in vitro model of radiation-induced oral mucositis. Our objective was the evaluation of the primary effects of gamma radiation, in vitro, on a monolayer of oral keratinocytes. Materials and Methods: Oral keratinocytes were obtained from surgically discarded oral mucosa (6 samples: 2 male and 4 female) and cultured in chemically defined serum free medium (EpiLife, Cascade Biologics, Portland, OR). When oral keratinocytes reached 60% to 70% confluency, they were irradiated with 0, 0.5, 1, 3, 5, and 8 Gy by a cobalt 60 source. Colony-forming efficiency (CFE) for cell proliferation was determined by plating irradiated cells in a 60-mm culture dish at a density of 25 cells/cm2. Surviving fraction (SF) of irradiated cells was evaluated 12 days postirradiation by fixing and staining cell colonies with 0.2% Crystal Violet. Colonies, which were larger than 16 cells, were counted and calculated AAOMS • 2003