Faculty Bibliography

Bone remodeling, along with tissue biomechanics, is critical for the clinical success of endosseous implants. This study evaluated the long-term evolution of the elastic modulus (GPa) and hardness (GPa) of cortical bone around human retrieved plateau root form implants. Thirty implant-in-bone specimens showing no clinical failure were retrieved from patients at different in-vivo times (0.3 to approximately 24 years) due to retreatment needs. After dehydration, specimens were embedded in methacrylate-based resin, sectioned along the bucco-lingual long axis and fixed to acrylic plates and nondecalcified processed to slides with approximately 50 mum in thickness. Nanoindentation testing was carried out under wet conditions on bone areas within the first three plateaus. Indentations (n = 120 per implant total) were performed with a maximum load of 300 muN (loading rate: 60 muN/s) followed by a holding and unloading time of 10 s and 2 s, respectively. Elastic modulus (E, GPa) and hardness (H, GPa) were computed. Both E and H values presented increased values as time in vivo elapsed (E: r = 0.84; H: r = 0.78). Significantly higher values for E and H were found after 5 years in vivo (p < 0.001). Maxillary or mandibulary arches or positioning did not affect mechanical properties, nor did implant surface treatment on the long-term bone biomechanical response (E: p >/= 0.09; H: p >/= 0.3). This work suggests that human cortical bone around plateau root form implants presents an increase in elastic modulus and hardness during the first 5 years following implantation and presents stable mechanical properties thereafter. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.

AbstractPurpose. To describe occurrences of oral squamous cell carcinoma (SCC) in patients who had received long-term pegylated liposomal doxorubicin (PLD) for ovarian cancer.Patients and Methods. In our cohort of patients on maintenance PLD for ovarian and related mullerian epithelial malignancies, we encountered two patients with invasive SCC of the oral cavity (one of them multifocal) and one with high-grade squamous dysplasia. Review of patients at our institution receiving PLD for recurrent ovarian cancer identified three additional patients. The duration of treatment, cumulative PLD dose, human papillomavirus (HPV) positivity, BRCA status, stage at diagnosis, outcome, and other characteristics are reviewed.Results. All five cases were nonsmokers with no known risk factors for HPV and four were negative for p16 expression. Four of the patients had known BRCA mutations whereas one tested negative. Cumulative doses of PLD were >1,600 mg/m(2) given over 30-132 months. Three had SCCs staged as T1N0 oral tongue, alveolar ridge (gingival), and multifocal oral mucosa; one had a T2N0 oral tongue; and one had dysplasia. After excision, two were given radiation but recurred shortly thereafter; the others remain well and have had no further exposure to cytotoxic drugs, including PLD.Conclusion. Awareness of this possible long-term complication during PLD treatment should enhance the likelihood of early detection of oral lesions in these patients. Decisions to continue maintenance PLD after complete response of the original cancer should perhaps consider the benefits of delaying ovarian cancer recurrence versus the possible risk for a secondary cancer.

Bone repair and regeneration is a dynamic process that involves a complex interplay between the (1) ground substance; (2) cells; and (3) milieu. Each constituent is integral to the final product, but it is often helpful to consider each component individually. While bone tissue engineering has capitalized on a number of breakthrough technologies, one of the most valued advancements is the incorporation of mesenchymal stem cells (SCs) into bone tissue engineering applications. With this new idea, however, came new found problems of guiding SC differentiation. Moreover, investigators are still working to understand which SCs source produces optimal bone formation in vitro and in vivo. Bone marrow-derived mesenchymal SCs and adipose-derived SCs have been researched most extensively, but other SC sources, including dental pulp, blood, umbilical cord blood, epithelial cells reprogrammed to become induced pluripotent SCs, among others, are being investigated. In Part II of this review series, we discuss the variety of cell types (e.g., osteocytes, osteoblasts, osteoclasts, chondrocytes, mesenchymal SCs, and vasculogenic cells) important in bone tissue engineering.

OBJECTIVE: The aim of this study was to evaluate the use of a collagen-based membrane compared with no treatment on guided bone regeneration by 3-dimensional computerized microtomography (muCT). STUDY DESIGN: Defects were created between the mesial and distal premolar roots of the second and third premolars (beagle dogs; n = 8). A collagen-based membrane (Vitala; Osteogenics Biomedical Inc., TX, USA) was placed in one of the defects (membrane group; n = 16), and the other was left untreated (no-membrane group; n = 16). Left and right sides provided healing samples for 2 and 16 weeks. Three-dimensional bone architecture was acquired by muCT and categorized as fully regenerated (F, bone height and width) or nonregenerated (N). RESULTS: Chi-square tests (95% level of significance) showed that tooth did not have an effect on outcome (P = .5). Significantly higher F outcomes were observed at 16 weeks than 2 weeks (P = .008) and in membrane group than in no-membrane group (P = .008). CONCLUSIONS: The collagen-based membrane influenced bone regeneration at the furcation.

ABSTRACT: It is well established that raw edges of the skin have a natural tendency to tube on themselves. Although this often presents a challenge for plastic surgeons, the following article demonstrates how the plastic surgeon can capitalize on this phenomenon to successfully recreate the natural appearance of curved anatomic elements. Two areas that are particularly susceptible to appearing "unnatural" after surgery are the earlobe and alar base. Herein, we present the concept of "autotubing" to recreate the natural curvature of these anatomic regions.

Melanoma is currently the fifth and sixth most common solid malignancy diagnosed in men and women, respectively. Although accounting for only 4% of cases of all cutaneous malignancies, melanoma accounts for more than 75% of all deaths from skin cancer. This article discusses epidemiology and risk factors, proper biopsy technique, advanced histologic evaluation of biopsy material, assessment of tumor thickness and staging, preoperative metastatic evaluation, excision margin, treatment of regional lymph nodes, treatment of recurrence, and some special clinical situations.

OBJECTIVES:: To evaluate a novel implant design for immediate implantation. This implant presents a specially designed expanded diameter midcrestal "wing" thread, which is aimed to provide added bone contact for greater insertion torque and primary stability. METHODS:: Mandibular premolars were extracted in 2 mongrel dogs, and immediate dental implants were inserted into the fresh extraction sockets. Implants were evaluated for stability using a resonance frequency analysis device immediately after insertion and after 4 and 8 weeks. Removal torque of 1 randomly selected implant in each hemimandible was measured as well. At 8 weeks, the remaining 6 implants were processed histologically. RESULTS:: Mean implant stability quotient at implant placement was 64.38 (5.03) and 74.5 (3.08) at 8 weeks. Average removal torque immediately after implant placement was 49.65 (20.3) N.cm and 98.33 (12.34) N.cm at 8 weeks. The mean bone-to-implant contact value at 8 weeks was 38.89% (7.65%). CONCLUSIONS:: The examined implant with the expanded diameter midcrestal "wing" thread showed good results of resonance frequency analysis and removal torque during the initial healing phase, and as such, it might be used for immediate implantation and loading.

Since obesity impairs wound healing and bone marrow (BM)-derived vasculogenic progenitor cells (PCs) are important for tissue repair, we hypothesize that obesity-impaired wound healing is due, in part, to impaired PC mobilization, trafficking, and function. Peripheral blood was obtained from nondiabetic, obese (BMI > 30, n = 25), and nonobese (BMI < 30, n = 17) subjects. Peripheral blood human (h)PCs were isolated, quantified, and functionally assessed. To corroborate the human experiments, 6-mm stented wounds were created on nondiabetic obese mice (TALLYHO/JngJ, n = 15) and nonobese mice (SWR/J, n = 15). Peripheral blood mouse (m)PCs were quantified and wounds were analyzed. There was no difference in the number of baseline circulating hPCs in nondiabetic, obese (hPC-ob), and nonobese (hPC-nl) subjects, but hPC-ob had impaired adhesion (p < 0.05), migration (p < 0.01), and proliferation (p < 0.001). Nondiabetic obese mice had a significant decrease in the number of circulating PCs (mPC-ob) at 7 (p = 0.008) and 14 days (p = 0.003) after wounding. The impaired circulating mPC-ob response correlated with significantly impaired wound closure at days 14 (p < 0.001) and 21 (p < 0.001) as well as significantly fewer new blood vessels in the wounds (p < 0.001). Our results suggest that obesity impairs the BM-derived vasculogenic PC response to peripheral injury and this, in turn, impairs wound closure.

This article focuses on the contribution of acellular dermal matrices (ADMs) to immediate breast reconstruction. The current literature on ADMs is reviewed and the potential advantages and disadvantages of their use are highlighted. Technical considerations on how to effectively use these materials is presented.