Faculty Bibliography

Summary Titanium or zirconium computer-aided design/computer-aided manufacturing abutments are now widely used for aesthetic implant treatments; however, information regarding microscopic structural differences that may influence the biological and mechanical outcomes of different implant systems is limited. Therefore, the characteristics of different connection systems were investigated. Optical microscopic observation and scanning electron microscopy showed different characteristics of two internal systems, namely the Astra Tech and the Replace Select system, and for different materials. The scanning electron microscopic observation showed for the Astra Tech that the implant-abutment interface seemed to be completely sealed for both titanium and zirconium abutments, both horizontally and sagittally; however, the first implant-abutment contact was below the fixture top, creating a microgap, and fixtures connected with titanium abutments showed significantly larger values (23.56 mum +/- 5.44 in width, and 168.78 mum +/- 30.39 in depth, P < 0.001). For Replace Select, scanning electron microscopy in the sagittal direction showed that the sealing of titanium and zirconium abutments differed. The seal between the implant-titanium and implant-zirconium abutments seemed to be complete at the butt-joint interface; however, the displacement of the abutment in relation to the fixture in the lateral direction was evident for both abutments with no statistical differences (P > 0.70), creating an inverted microgap. Thus, microscopy evaluation of two commonly used internal systems connected to titanium or zirconium abutments showed that the implant-abutment interface was perfectly sealed under no-loading conditions. However, an inverted microgap was seen in both systems, which may result in bacterial accumulation as well as alteration of stress distribution at the implant-abutment interface.

ABSTRACT: Microporous scaffolds designed to improve bony repair have had limited success; therefore, we sought to evaluate whether time-released porous scaffolds with or without recombinant bone morphogenetic protein 2 (rhBMP-2) could enhance stem cell osteoinduction. Custom-made 15/85 hydroxyapatite/beta-tricalcium phosphate scaffolds were left empty (E) or filled with rhBMP-2 (E+), calcium sulfate (CS), or CS and rhBMP-2 (CS+). All scaffolds were placed in media and weighed daily. Conditioned supernatant was analyzed for rhBMP-2 and then used to feed human adipose-derived mesenchymal stem cells (ASCs). Adipose-derived mesenchymal stem cell ALP activity, OSTERIX expression, and bone nodule formation were determined. E scaffolds retained 97% (SD, 2%) of the initial weight, whereas CS scaffolds had a near-linear 30% (SD, 3%) decrease over 60 days. E+ scaffolds released 155 (SD, 5) ng of rhBMP-2 (77%) by day 2. In contrast, CS+ scaffolds released only 30 (SD, 2) ng (10%) by day 2, and the remaining rhBMP-2 was released over 20 days. Conditioned media from E+ scaffolds stimulated the highest ALP activity and OSTERIX expression in ACSs on day 2. However, after day 6, media from CS+ scaffolds stimulated the highest ALP activity and OSTERIX expression in ASCs. Adipose-derived mesenchymal stem cells exposed to day 8 CS+-conditioned media produced significantly more bone nodules (10.1 [SD, 1.7] nodules per high-power field) than all other scaffolds. Interestingly, day 8 conditioned media from CS scaffolds simulated significantly more bone nodules than either E or E+ scaffold (P < 0.05 for both). Time-released hydroxyapatite/beta-tricalcium phosphate porosity provides sustained growth factor release, enhances ASC osteoinduction, and may result in better in vivo bone formation.

We review the literature on medial orbital wall fractures and perform a meta-analysis on outcomes with the transcaruncular approach. The reported incidence for this injury ranges widely, although diagnosis can be made effectively with clinical examination and computed tomography. Clinical sequelae can include rectus entrapment or herniation, enophthalmos, and diplopia. Local injuries occurring in high concordance include concomitant fractures of the orbital floor and nasal fractures, although anterior cranial fossa extension, ocular trauma, other craniofacial injuries, and polytrauma must be ruled out. Indications for operative intervention include large defects, early or persistent enophthalmos particularly if causing diplopia, and rectus muscle entrapment.Various surgical approaches to the medial orbit have been described; however, the transcaruncular approach offers direct, reliable access without creating a cutaneous scar on the central face. A meta-analysis was performed on all studies reporting outcomes of the transcaruncular approach. A total of 228 cases were pooled, finding a favorable overall complication rate of 2.6%. Half of these complications required surgical correction and half resolved nonoperatively.Medial orbital wall fractures are an increasingly appreciated injury requiring clinical and radiologic assessments. When indicated, reconstruction of the medial orbital wall can be safely and effectively performed with the transcaruncular approach. Additional prospective outcomes studies are required to elucidate (1) the incidence of medial orbital wall fractures, (2) indications for operative versus nonoperative management, and (3) outcomes analysis of the transcaruncular approach compared with other approaches.

This study aimed to evaluate Y-TZP surface after different airborne particle abrasion protocols. Seventy-six Y-TZP ceramic blocks (5×4×4) mm3 were sintered and polished. Specimens were randomly divided into 19 groups (n=4) according to control group and 3 factors: a) protocol duration (2 and 4 s); b) particle size (30 μm, alumina coated silica particle; 45 μm, alumina particle; and 145 μm, alumina particle) and; c) pressure (1.5, 2.5 and 4.5 bar). Airborne particle abrasion was performed following a strict protocol. For qualitative and quantitative results, topography surfaces were analyzed in a digital optical profilometer (Interference Microscopic), using different roughness parameters (Ra, Rq, Rz, X-crossing, Mr1, Mr2 and Sdr) and 3D images. Surface roughness also was analyzed following the primer and silane applications on Y-TZP surfaces. One-way ANOVA revealed that treatments (application period, particle size and pressure of particle blasting) provided significant difference for all roughness parameters. The Tukey test determined that the significant differences between groups were different among roughness parameters. In qualitative analysis, the bonding agent application reduced roughness, filing the valleys in the surface. The protocols performed in this study verified that application period, particle size and pressure influenced the topographic pattern and amplitude of roughness.

Diabetic foot ulcers (DFUs) are a significant and rapidly growing complication of diabetes and its effects on wound healing. Over half of diabetic patients who develop a single ulcer will subsequently develop another ulcer of which the majority will become chronic non-healing ulcers. One-third will progress to lower extremity amputation. Over the past decade, the outcomes for patients with DFUs ulcers have not improved, despite advances in wound care. Successful treatment of diabetic foot ulcers is hindered by the lack of targeted therapy that hones in on the healing processes dysregulated by diabetes. Stem cells are a promising treatment for DFUs as they are capable of targeting, as well as bypassing, the underlying abnormal healing mechanisms and deranged cell signaling in diabetic wounds and promote healing. This review will focus on existing stem cell technologies and their application in the treatment of DFUs.

BACKGROUND: If not effectively treated, groin wound infections following lower extremity revascularization (LER) may result in graft or limb loss. METHODS: A retrospective review was performed of all patients who underwent muscle flap transposition by a single surgeon after LER between 2006 and 2010. RESULTS: Twenty-nine muscle transposition flaps were performed in 24 patients (21 sartorius, 6 rectus femoris, and 2 gracilis). Nineteen were for treatment of groin wound infections, two for treatment of lymphocele, one for coverage of exposed graft in the setting of pyoderma gangrenosum, and seven for infection prophylaxis. Two graft losses followed flap placement. The limb loss rate was 4%. When performed for therapeutic purposes, graft salvage rates were 100% for autogenous and 92% for synthetic grafts. CONCLUSIONS: Muscle transposition flaps are an effective means of graft salvage in the setting of groin wound complications following LER and should be considered for infection prophylaxis in high-risk patients.

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.