Faculty Bibliography

OBJECTIVES: To compare the reliability of the disto-facial (DF) and mesio-lingual (ML) cusps of an anatomically correct zirconia (Y-TZP) crown system. The research hypotheses tested were: (1) fatigue reliability and failure mode are similar for the ML and DF cusps; (2) failure mode of one cusp does not affect the failure of the other. METHODS: The average dimensions of a mandibular first molar crown were imported into CAD software; a tooth preparation was modelled by 1.5 mm marginal high reduction of proximal walls and occlusal surface by 2.0 mm. The CAD-based tooth preparation was milled and used as a die to fabricate crowns (n=14) with porcelain veneer on a 0.5 mm Y-TZP core. Crowns were cemented on composite reproductions of the tooth preparation. The crowns were step-stress mouth motion fatigued with sliding (0.7 mm) a tungsten-carbide indenter of 6.25 mm diameter down on the inclines of either the DF or ML cusps. Use level probability Weibull curve with use stress of 200 N and the reliability for completion of a mission of 50,000 cycles at 200 N load were calculated. RESULTS: Reliability for a 200 N at 50,000 cycles mission was not different between tested cusps. SEM imaging showed large cohesive failures within the veneer for the ML and smaller for the DF. Fractures originated from the contact area regardless of the cusp loaded. CONCLUSION: No significant difference on fatigue reliability was observed between the DF compared to the ML cusp. Fracture of one cusp did not affect the other

Although radiation therapy is a major risk factor for the development of lymphedema following lymphadenectomy, the mechanisms responsible for this effect remain unknown. The purpose of this study was therefore to determine the effects of radiation on lymphatic endothelial cells (LECs) and lymphatic function. The tails of wild-type or acid sphingomyelinase (ASM)-deficient mice were treated with 0, 15, or 30 Gy of radiation and then analyzed for LEC apoptosis and lymphatic function at various time points. To analyze the effects of radiation fibrosis on lymphatic function, we determined the effects of transforming growth factor (TGF)-beta1 blockade after radiation in vivo. Finally, we determined the effects of radiation and exogenous TGF-beta1 on LECs in vitro. Radiation caused mild edema that resolved after 12-24 wk. Interestingly, despite resolution of tail edema, irradiated animals displayed persistent lymphatic dysfunction. Radiation caused loss of capillary lymphatics and was associated with a dose-dependent increase in LEC apoptosis. ASM-/- mice had significantly less LEC apoptosis; however, this finding did not translate to improved lymphatic function at later time points. Short-term blockade of TGF-beta1 function after radiation markedly decreased tissue fibrosis and significantly improved lymphatic function but did not alter LEC apoptosis. Radiation therapy decreases lymphatic reserve by causing depletion of lymphatic vessels and LECs as well as promoting soft tissue fibrosis. Short-term inhibition of TGF-beta1 activity following radiation improves lymphatic function and is associated with decreased soft tissue fibrosis. ASM deficiency confers LEC protection from radiation-induced apoptosis but does not prevent lymphatic dysfunction.

The authors' experience with the supraclavicular approach for the treatment of patients with primary thoracic outlet syndrome (TOS) and for patients with recurrent TOS or iatrogenic brachial plexus injury after prior transaxillary first rib resection is presented. The records of 33 patients (34 plexuses) with TOS who presented for evaluation and treatment were analyzed. Of these, 12 (35%) plexuses underwent surgical treatment, and 22 (65%) plexuses were managed non-operatively. The patients who were treated non-operatively and had an adequate follow-up (n = 11) were used as a control group. Of the 12 surgically treated patients, five patients underwent primary surgery; four patients had secondary surgery for recurrent TOS; and three patients had surgery for iatrogenic brachial plexus injury. All patients presented with severe pain, and most of them had neurologic symptoms. All nine (100%) patients who underwent primary surgery (n = 5) and secondary surgery for recurrent TOS (n = 4) demonstrated excellent or good results. On the other hand, six (54%) of the 11 patients from the control group had some benefit from the non-operative treatment. Reoperation in three patients with iatrogenic brachial plexus injury resulted in good result in one case and in fair results in two patients; however, all patients were pain-free. No complications were encountered. Supraclavicular exploration of the brachial plexus enables precise assessment of the contents of the thoracic inlet area. It allows for safe identification and release of all abnormal anatomical structures and complete first rib resection with minimal risk to neurovascular structures. Additionally, this approach allows for the appropriate nerve reconstruction in cases of prior transaxillary iatrogenic plexus injury. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11552-009-9253-0) contains supplementary material, which is available to authorized users.

Completion of the human genome project approximately 15 years ago was followed closely by advancements in array technology. Investigators quickly applied this new powerful tool to the genomic and proteomic study of oral squamous cell carcinoma (OSCC). Resultant publications documented chromosome, gene, mRNA, and protein alterations that characterize oral cancer. In this review, we summarize how the genomic, proteomic, and epigenetic array studies have provided insight into the process of oral carcinogenesis. We discuss the significant limitations and requirement for validation of these array studies. We also review the manner in which state-of-the-art, high-throughput approaches are being used to search for salivary and serum oral cancer biomarkers

PURPOSE: To evaluate the bone healing response to different implant root shape designs in a dog model. MATERIALS AND METHODS: Three by eight millimeter screw-type short-pitch (SP) and large-pitch (LP) implants (Intra-Lock International, Boca Raton, FL, USA), and 4.5 x 6 mm plateau (P) implants (Bicon LLC, Boston, MA, USA) were placed along the proximal tibia of six dogs for 2 and 4 weeks. The combination of implant design and final osteotomy drilling resulted in healing chambers for the LP and P implants. The implants were nondecalcified processed to plates of approximately 30-microm thickness and were evaluated by optical microscopy for healing patterns and bone-to-implant contact (BIC). One-way analysis of variance at 95% level of significance and Tukey's test were utilized for multiple comparisons among the groups' BIC. RESULTS: Microscopy showed a approximately 150-microm region of newly deposited bone along the whole perimeter of SP implants, near the edge of the LP implant threads, and plateau tips for P implants. Rapid woven bone formation and filling was observed in regions where surgery and implant design resulted in healing chambers. No significant differences in BIC were observed (p > .75). CONCLUSIONS: Different implant design/surgical protocol resulted in varied bone healing patterns. However, the BIC and bone morphology evolution between implant designs were comparable. Regardless of the combination between implant design and final osteotomy drilling, bone morphology evolution from 2 to 4 weeks was comparable.

Medicinal leeches are used to control venous congestion. Aeromonas in the leech gut are essential for digestion of blood. This case report describes a patient who had Aeromonas bacteremia develop after leeching. He had an injury to his hand that required replantation of his thumb. Following the surgery, leech therapy was started with ampicillin-sulbactam prophylaxis. Sepsis developed. Blood cultures were positive for Aeromonas that were resistant to ampicillin-sulbactam. The antibiotic was changed to ciprofloxacin on the basis of the sensitivity profile of the organisms. Cultures from the leech bathwater confirmed it as the source of the Aeromonas. Clinicians who use leech therapy must be aware that leeches can harbor Aeromonas species resistant to accepted prophylactic antibiotics and that sepsis may occur

BACKGROUND: Restoration of shoulder external rotation is very important for upper extremity function. The purpose of this study was to present the authors' experience with secondary restoration of external rotation in patients with obstetrical brachial plexus palsy. METHODS: From 1978 to 2002, 46 children underwent secondary surgery for restoration of external rotation. Outcomes were analyzed in relation to various factors, including the type of procedure, muscle transfer only versus nerve reconstruction and muscle transfer, denervation time, type of injury (Erb versus global palsy), and severity score. In addition, the effect of restoration of external rotation on the final outcome of shoulder abduction was assessed. RESULTS: There was significant improvement in every case (p < 0.01) between preoperatively and postoperatively. The overall mean postoperative Mallet score for the group undergoing muscle transfer only was 3.95, whereas in the nerve reconstruction and muscle transfer group, the score was 3.88 (p >0.05). The resulting gain in external rotation was 99 degrees versus 93.8 degrees. In both populations, a very significant improvement (p <0.0001) was identified in the final outcome of shoulder abduction (109 degrees after muscle transfer versus 48.3 degrees before muscle transfer, and 112 degrees postoperatively after neurotization and muscle transfer versus 43.8 degrees before any surgery). Patients with Erb palsy had a better but not significant result (p >0.05; p = 0.94), compared with those with global palsy in both Mallet score (3.77 versus 3.76) and final active external rotation (81.7 degrees versus 77.6 degrees). CONCLUSION: Secondary surgery for the restoration of external rotation is a rewarding procedure, which also significantly improves the final outcome of shoulder abduction