as A or B. Each MAD was used for 3 months. Three polysomnographic evaluations (PSGE) were performed: a baseline (night 1) and two with the MAD (nights 2 and 3 for A or B). The Epworth Sleepiness Scale (ESS) and a Visual analog scale for fatigue (VAS-F) were completed before each PSGE. Paired-sample t tests were used for statistical comparison. Results: The mean AHI observed after the use of both MAD differed from that observed during the baseline night (A: 10.7 ± 3.4 and B: 7.1 ± 2.8 vs. baseline: 14.2 ± 2.6, p 6 0.04). The mean AHI following the use of appliance B was lower than that obtained after the use of appliance A(p = 0.015). ESS scores were significantly lower with both MAD (A: 7.7 ± 1.4 and B: 9.6 ± 1.7) as compared to baseline (11.8 ± 1.5, p 6 0.04). In addition, VAS-F score after the use of appliance A was lower than baseline VAS-F (3.6 ± 0.7 vs. 5.3 ± 0.6, p = 0.03). Conclusions: Both MAD seems effective in decreasing AHI and daytime sleepiness in patients with mild-to-moderate OSAS. Only the MAD A was associated with a diminution of self-reported fatigue. However, MAD B seems to be associated with a more important reduction in AHI. A total of 17 subjects are expected to complete the study by the end of 2006. (Supported by FODQ-FRSQ & CIHR). doi:10.1016/j.sleep.2006.07.220 P411 Rapid prototyping technology used to achieve better results in oral appliance therapy for obstructive sleep apnea/hypopnea syndrome: A case report Ricardo C. Barbosa 1,* , Jorge V.L. Silva 2 , Ailton S. Barbara 2 , Maria F. Gouveia 2 1 Universidade de Sa ˜o Paulo General Hospital, Sa ˜o Paulo, SP, Brazil 2 CenPRA,‘‘Renato Acher’’ Research Center, Campinas, SP, Brazil Introduction and objective: Sleep-disordered breathing ranges from partial airway collapse and increased upper-airway resistance manifested as loud snoring and brief arousals to total or partial recurrent airway collapse. Obstructive sleep apnea/hypopnea syndrome (OSAHS) leads to risks of motor vehicle accidents, increased cardiovascular morbidity and mortality 1 . Therefore, even mild degree OSAHS demands an effec- tive treatment. Hence, oral appliance therapy (OAT) has become a treatment alternative for OSAHS. Results of OAT vary depending upon appliance design and the amount of advancement 2 . Application of Rapid Proto- typing Technology (RPT) using SLS (Selective Laser Sintering) in medicine is a new and exciting field created by the convergence of three different technologies: med- ical imaging acquisition, computer graphics and rapid prototyping. Medical images in digital format are obtained by the use of CT and MRI tomography to materialize an organic structure, in plastic material, in its original size or dimensions, allowing therapeutic planning and 3D technical essays. The objective of this case report is to present the PR exam as an auxiliary to reach better results in OSAHS OA therapy. Methods: A dynamic OA was applied in a polissono- graphic (PSG1) confirmed OSAHS patient, male, age = 67, BMI = 25.5, evident facial deformity. Post- treatment PSG2 indexes were obtained: Respiratory Disturbance Index (RDI), Epworth Sleepiness Scale (ESS) subjective daytime sleepiness scores 3 , SatO2 min. With the objective of improving the results, the RPT were performed, and a small surgical procedure was planned and executed – extraction of 48 and occlusal adjustment decreasing facial vertical dimension. A new dynamic OA was made and applied, and new PSG3 indexes were obtained. Results: The results are: PSG1 (RDI = 21; SatO2 = 80%; ESS = 18). PSG2 (RDI = 44.5; SatO2 = 74%; ESS = 18). PSG3 (RDI = 5.2; SatO2 = 89%; ESS = 7). Discussion and Conclusion: Mandibular advancement with a dental appliance effectively reduces the sleep- breathing disorder measured as frequency of apneas, and a pronounced mandibular advancement did not show a greater improvement of the medical problem compared to less advancement for patients with mild to moderate OSA 4 . However, in the presence of some facial deformity, the ideal mandibular advancement is not possible and the surgical procedure must be per- formed. With the RPT we can plan and make the results more predictable, also promoting less aggression to the patient and increasing the possibilities of better results. doi:10.1016/j.sleep.2006.07.221 P412 Efficacy of an oral appliance (OA) compared to nCPAP over oxidative stress parameters in obstructive sleep apnea (OSA) patients – preliminary results Dal-Fabbro Cibele * , S.A. Garbuio, V. D’Almeida, R.F. Santos, L.R.S. Bittencourt, S. Tufik Disciplina de Medicina e Biologia do Sono – UNIFESP, Sa ˜ o Paulo, SP, Brazil Objectives: To evaluate the effect of an OA compared to nCPAP over oxidative stress in OSA patients. Design: Randomized, double blind, placebo controlled. Methods and measurements: Thirteen adult patients with moderate to severe OSA (AHI P 20) were evaluated (BMI 6 35 kg/m 2 ). They were divided in two groups (OA/placebo (1); placebo/OA(2)) (double blind). The OA was a repositioning mandibular appliance with pro- gressive adjustment and the placebo appliance was a splint at lower arch. The study was divided in four phas- es: baseline data (A), after 1 month of OA or placebo Abstracts / Sleep Medicine 7 (2006) S1–S127 S93