Faculty Bibliography

Purpose: Fracture is a frequent complication of resinous prostheses. The purpose of this study was to evaluate the effect of thickness on flexural strength of a resinous prosthesis containing a prosthetic tooth. Materials and Methods: Beam-shaped specimens 65-mm long, 12-mm wide, and 1, 2, 3, 4, or 6 mm in thickness were made from high-impact strength polymethyl methacrylate denture base material, each containing a resin-based molar prosthetic tooth at the center of the beam. A group of 3-mm-thick specimens without a prosthetic tooth (n = 7) were also made. Specimens were aged artificially, loaded in three-point flexure, examined fractographically, and analyzed. Results: The 1- and 2-mm-thick beams underwent considerable deformation at low loads. Maximum loads varied considerably from 0.6 kg (1-mm beams) to 38 kg (6-mm beams). The 3-, 4-, and 6-mm beam groups all underwent brittle fracture, with mean relative flexural strengths of approximately 73 MPa. Denture teeth reduced the relative flexural strength of resin beams by 0.7x. Fracture initiation sites were generally at tiny surface defects, but did not directly involve denture teeth. Denture resin fracture toughness was 3.2 MPa m1/2, and modulus of rupture was 104 MPa. Conclusion: Denture teeth substantially decreased the strength of resinous beams. Increased thickness markedly increased the load-bearing capacity of resinous beams containing denture teeth. Beams less than 2 mm in thickness with denture teeth were weakened substantially more than comparable beams of 2 mm or more in thickness. Surface finish was of critical importance. Fracture toughness was calculated fractographically, facilitating future forensic examination of clinically failed resinous prostheses. Int J Prosthodont 2012;25:53-59.

BACKGROUND: : Patients with syndromic craniosynostosis and midface hypoplasia are often treated with Le Fort III advancement. The authors present four patients with extraordinarily long-term follow-up (in excess of 20 years). METHODS: : An institutional review board-approved retrospective chart review was performed on all patients with syndromic craniofacial synostosis who underwent Le Fort III advancement. Patients with greater than 20 years of cephalometric and photographic records were identified. Lateral cephalograms were obtained preoperatively, immediately postoperatively, at 1-year follow-up, and at long-term follow-up. Cephalograms were traced, digitized, and averaged. Fifty cephalometric landmarks were identified for serial measurements. RESULTS: : Of the four patients identified, one had Apert syndrome and three had Crouzon syndrome. Average age at the time of Le Fort III advancements was 11 years (range, 4 to 20 years). Average length of postoperative follow-up was 25 years (+/-5 years). No patient had significant anterior midfacial growth following Le Fort III advancement. Both young patients (<10 years) had substantial vertical inferior midfacial growth after advancement. CONCLUSIONS: : These data demonstrate that the Le Fort III segment of children with syndromic craniosynostosis does not grow significantly forward. Moreover, the traditional Le Fort III osteotomy does not provide the amount of midface advancement necessary to avoid phenotypic recidivism in these syndromic patients. This study also suggests that patients undergoing Le Fort III advancement appear to have zygomatic effacement and ptosis of the overlying soft tissue with deepening of the facial folds; collectively, it is suggested that these changes give the appearance of accelerated facial aging. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Therapeutic, V

OBJECTIVES: To compare the biomechanical fixation and histomorphometric parameters between two implant surfaces: non-washed resorbable blasting media (NWRBM) and alumina-blasted/acid-etched (AB/AE), in a dog model. MATERIAL AND METHODS: The surface topography was assessed by scanning electron microscopy, optical interferometry and chemistry by X-ray photoelectron spectroscopy (XPS). Six beagle dogs of approximately 1.5 years of age were utilized and each animal received one implant of each surface per limb (distal radii sites). After a healing period of 3 weeks, the animals were euthanized and half of the implants were biomechanically tested (removal torque) and the other half was referred to nondecalcified histology processing. Histomorphometric analysis considered bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Following data normality check with the Kolmogorov-Smirnov test, statistical analysis was performed by paired t-tests at 95% level of significance. RESULTS: Surface roughness parameters S(a) (average surface roughness) and S(q) (mean root square of the surface) were significantly lower for the NWRBM compared with AB/AE. The XPS spectra revealed the presence of Ca and P in the NWRBM. While no significant differences were observed for both BIC and BAFO parameters (P>0.35 and P>0.11, respectively), a significantly higher level of torque was observed for the NWRBM group (P=0.01). Bone morphology was similar between groups, which presented newly formed woven bone in proximity with the implant surfaces. CONCLUSION: A significant increase in early biomechanical fixation was observed for implants presenting the NWRBM surface.

ABSTRACT: There is tremendous interest in autologous fat grafting for the management of soft tissue volume deficiencies, treatment of cutaneous injuries, and regeneration of missing parts. Given its relative abundance and proximity to the surface of the skin, adipose tissue seems an excellent choice for the treatment of both congenital and acquired soft tissue defects, but the mesenchymal stem cells contained within the fat may provide unexpected opportunities for tissue replacement and repair. Although adipose transfer has been successfully used for reconstructive purposes since the end of the 19th century, numerous controversies about adipose harvesting, processing, delivery, survival, and efficacy still persist today. The purpose of this article was to highlight current practices, areas of controversy, and near-term future applications of fat grafting for reconstruction of the face.

OBJECTIVE: Catheter-related infection remains a cause of morbidity in the use of external ventricular drains (EVDs). The aim of this retrospective single-center study was to assess the rate and factors related to ventriculostomy infections in the setting of the published literature. METHODS: Patients that underwent EVD placement in a single-center were retrospectively reviewed. Diagnosis, treatment, hospital course, and infection-related data were collected and analyzed in reference to ventriculitis rates. The protocols for EVD placement and maintenance were reviewed. RESULTS: Of 343 patients, 12 acquired an EVD infection. No significant differences existed between those with and without ventriculitis for age, sex, underlying diagnosis, or concomitant systemic infection. Although not significant, concomitant systemic infection existed in 4.7% of patients with ventriculitis versus 1.5% without. There was a significant difference in length of EVD placement in patients with ventriculitis (20.9 +/- 15.3 days) versus those without (12.1 +/- 18.2; P = 0.005). Coagulase-negative Staphylococcus and Staphylococcus aureus represented the most commonly associated pathogens. With an overall cumulative incidence of 3.5%, our rate compared favorably to the published literature (cumulative incidence 9.5%; range, 3.9%-23.2%). CONCLUSIONS: Catheter-related infection remains an important complication of EVD placement. Of factors evaluated, length of time of catheter placement has the most notable relationship to infection incidence, suggesting that early drain removal should be a goal whenever medically appropriate.

PURPOSE: Primary stability has been regarded as a key factor to ensure uneventful osseointegration of dental implants. Such stability is often achieved by placing implants in undersized drilled bone. The present study evaluated the effect of drilling dimensions in insertion torque and early implant osseointegration stages in a beagle dog model. MATERIALS AND METHODS: Six beagle dogs were acquired and subjected to bilateral surgeries in the radii 1 and 3 weeks before death. During surgery, 3 implants, 4 mm in diameter by 10 mm in length, were placed in bone sites drilled to 3.2 mm, 3.5 mm, and 3.8 mm in diameter. The insertion torque was recorded for all samples. After death, the implants in bone were nondecalcified processed and morphologically and morphometrically (bone-to-implant contact and bone area fraction occupancy) evaluated. Statistical analyses were performed using the Kruskal-Wallis test followed by Dunn's post hoc test for multiple comparisons at the 95% level of significance. RESULTS: The insertion torque levels obtained were inversely proportional to the drilling dimension, with a significant difference detected between the 3.2-mm and 3.8-mm groups (P = .003). Despite a significant increase in the bone-to-implant contact over time in vivo for all groups (P = .007), no effect for the drilling dimension was observed. Additionally, no effect of the drilling dimension and time was observed for the bone area fraction occupancy parameter (P = .31). The initial healing pathways differed between implants placed in bone drilled to different dimensions. CONCLUSIONS: Although different degrees of torque were observed with different drilling dimensions and these resulted in different healing patterns, no differences in the histometrically evaluated parameters were observed.

BACKGROUND:Preoperative lymphoscintigraphy for sentinel node biopsy (SNB) combined with intra-operative gamma-probe detection often identifies nodes within the pelvis. This study investigates the role of pelvic SNB harvest. METHODS:Retrospective review of eighty-two stage I/II melanoma patients with primary tumour on the lower limb and trunk who underwent groin SNB, either inguinal or pelvic or both, over a three year period. RESULTS:Of the 82 patients, 19 had positive SNBs (24%), all of which were inguinal nodes. None of the 11 patients with pelvic nodes removed had a positive pelvic node. The median follow-up period was 18 months (SD: 10.8; range: 8-43). Although the complication rate was higher following pelvic SNB, the difference was not statistically significant (p > 0.5). The average operative time for an inguinal SNB was 92 min, and increased significantly to 134 min for a pelvic SNB (p < 0.0001). Lymphoscintigraphy of trunk and thigh melanomas identified individual tracks to be leading directly from the tumour to a pelvic node(s). However, when the primary tumour was located at or below the knee, pelvic nodes identified by lymphoscintigraphy appeared to be second level nodes. CONCLUSION/CONCLUSIONS:A lymphoscintigraphy protocol that includes dynamic images obtained in frequent intervals following injection of the radiotracer combined with thorough preoperative analysis of the lymphoscintigraphy scans and effective communication between the radiologist and the surgeon allows accurate identification of the primary tracks and prevent unnecessary harvest of second echelon pelvic lymph nodes. In patients with significant co-morbidities due consideration is required before harvesting pelvic sentinel nodes.

OBJECTIVES: This study compared the biomechanical fixation and bone-to-implant contact (BIC) of implants with different surfaces treatment (experimental - resorbable blasting media-processed nanometer roughness scale surface, and control - dual acid-etched) in a dog model. MATERIAL AND METHODS: Surface characterization was made in six implants by means of scanning electron microscopic imaging, atomic force microscopy to evaluate roughness parameters, and X-ray photoelectron spectroscopy (XPS) for chemical assessment. The animal model comprised the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six mongrel dogs, which remained in place for 2 or 4 weeks. Half of the specimens were biomechanically tested (torque), and the other half was subjected to histomorphologic/morphometric evaluation. BIC and resistance to failure measures were each evaluated as a function of time and surface treatment in a mixed model ANOVA. RESULTS: Surface texturing was significantly higher for the experimental compared with the control surface. The survey XPS spectra detected O, C, Al, and Ti at the control group, and Ca ( approximately 0.2- 0.9%) and P ( approximately 1.7- 4.1%) besides O, C, Al, and Ti at experimental surfaces. While no statistical difference in BIC was found between experimental and control surfaces or between 2 and 4 weeks in vivo, both longer time and use of experimental surface significantly increased resistance to failure. CONCLUSIONS: The experimental surface resulted in enhanced biomechanical fixation but comparable BIC relative to control, suggesting higher bone mechanical properties around the experimental implants.