Faculty Bibliography

OBJECTIVES: This study compared the reliability and fracture patterns of zirconia cores veneered with pressable porcelain submitted to either axial or off-axis sliding contact fatigue. METHODS: Forty-two Y-TZP plates (12mm x 12mm x 0.5mm) veneered with pressable porcelain (12mm x 12mm x 1.2mm) and adhesively luted to water aged composite resin blocks (12mm x 12mm x 4mm) were stored in water at least 7 days prior to testing. Profiles for step-stress fatigue (ratio 3:2:1) were determined from single load to fracture tests (n=3). Fatigue loading was delivered on specimen either on axial (n=18) or off-axis 30 degrees angulation (n=18) to simulate posterior tooth cusp inclination creating a 0.7mm slide. Single load and fatigue tests utilized a 6.25mm diameter WC indenter. Specimens were inspected by means of polarized-light microscope and SEM. Use level probability Weibull curves were plotted with 2-sided 90% confidence bounds (CB) and reliability for missions of 50,000 cycles at 200N (90% CB) were calculated. RESULTS: The calculated Weibull Beta was 3.34 and 2.47 for axial and off-axis groups, respectively, indicating that fatigue accelerated failure in both loading modes. The reliability data for a mission of 50,000 cycles at 200N load with 90% CB indicates no difference between loading groups. Deep penetrating cone cracks reaching the core-veneer interface were observed in both groups. Partial cones due to the sliding component were observed along with the cone cracking for the off-axis group. No Y-TZP core fractures were observed. CONCLUSIONS: Reliability was not significantly different between axial and off-axis mouth-motion fatigued pressed over Y-TZP cores, but incorporation of sliding resulted in more aggressive damage on the veneer

Since the founding of the osseointegration concept, the characteristics of the interface between bone and implant, and possible ways to improve it, have been of particular interest in dental and orthopaedic implant research. Making use of standardized tools of analysis and terminology, we present here a standardized characterization code for osseointegrated implant surfaces. This code describes the chemical composition of the surface, that is, the core material, such as titanium, and its chemical or biochemical modification through impregnation or coating. This code also defines the physical surface features, at the micro- and nanoscale, such as microroughness, microporosity, nanoroughness, nanotubes, nanoparticles, nanopatterning and fractal architecture. This standardized classification system will allow to clarify unambiguously the identity of any given osseointegrated surface and help to identify the biological outcomes of each surface characteristic.

BACKGROUND: Novel implant surface treatments with a nanothickness bioactive ceramic deposition onto rough surfaces have been recently introduced. This study aims to evaluate histologically and histomorphometrically (bone-to-implant contact [BIC] and bone area fraction occupancy [BAFO]) the early bone response to plasma-sprayed calcium-phosphate (PSCaP)-coated versus a 300- to 500-nm thickness bioactive ceramic nano-coated plateau root form implants in a rabbit femur model. METHODS: A total of 48 plateau root form implants were bilaterally placed in the distal aspect of the femur of 12 white New Zealand rabbits, remaining for 20, 30, and 60 days in vivo (n = 4 animals per time in vivo, n = 2 implants per surface per animal). After sacrifice, the implants in bone were non-decalcified processed to slides of approximately 30 mum thickness, and were morphologically and morphometrically (BIC and BAFO) evaluated. RESULTS: Higher degrees of bone structural organization were temporally observed for the PSCaP surface compared to the nano surface over time. BIC and BAFO was significantly higher (P <0.05) for PSCaP at all implantation times evaluated. CONCLUSIONS: Within the limits of this study it is possible to state that bioactive ceramic coatings of both thicknesses were biocompatible and osteoconductive. However, the early bone response was favored by the presence of the thicker PSCaP coating.

Rodent pain models play an important role in understanding the mechanisms of nociception and have accelerated the search for new treatment approaches for pain. Creating an objective metric for orofacial nociception in these models presents significant technical obstacles. No animal assay accurately measures pain-induced orofacial dysfunction that is directly comparable to human orofacial dysfunction. We developed and validated a high throughput, objective, operant, nociceptive animal assay, and an instrument to perform the assay termed the dolognawmeter, for evaluation of conditions known to elicit orofacial pain in humans. Using the device our assay quantifies gnawing function in the mouse. We quantified a behavioral index of nociception and demonstrated blockade of nociception in three models of orofacial pain: (1) TMJ inflammation, (2) masticatory myositis, and (3) head and neck cancer. This assay will be useful in the study of nociceptive mediators involved in the development and progression of orofacial pain conditions and it will also provide a unique tool for development and assessment of new therapeutic approaches

Since 1976, experimental and clinical studies have suggested the superiority of vascularized nerve grafts. In this study, a 27-year experience of the senior author is presented regarding vascularized nerve grafts and fascia for complex upper extremity nerve reconstruction. The factors influencing outcomes as well as a comparison with conventional nerve grafts is presented. Since 1981, 21 vascularized nerve grafts, other than vascularized ulnar nerve, were used for reconstruction of nerve injuries in the upper extremity. Indications were prolonged denervation time, failure of the previously used conventional nerve grafts, and excessive scar in the recipient site. Injury was in the hand/wrist area (n = 5), in the forearm (n = 4), in the elbow (n = 2), in the arm (n = 4), or in the plexus (n = 6). Vascularized sural (n = 9), saphenous (n = 8), superficial radial (n = 3), and peroneal (superficial and deep) nerves were used. The mean follow-up was 31.4 months. Vascularized nerve grafts for upper extremity injuries provided good to excellent sensory return in severely scarred upper extremities in patients in whom conventional nerve grafts had failed. They have also provided relief of causalgia after painful neuroma resection and motor function recovery in selective cases even for above the elbow injuries. Small diameter vascularized nerve grafts should be considered for bridging long nerve gaps in regions of excessive scar or for reconstructions where conventional nerve grafts have failed

Background: Calcium hydroxylapatite (CaHA, Radiesse) is approved by the Food and Drug Administration for treatment of moderate to severe wrinkles and folds, including nasolabial folds (NLF). A pivotal NLF split-face study previously compared the performance of Radiesse to human-based collagen at six months and safety of Radiesse through one year. Objective: The authors assess the long-term safety and effectiveness of Radiesse for the treatment of NLF. Postapproval long-term results now extend to more than three years and are presented here. Methods: This study reports an extension phase of a previously reported one-year premarket study of 117 patients comparing Radiesse to collagen. During the initial study, patients were treated to optimal correction and then followed for 12 months; they were offered retreatment with Radiesse between six and 12 months in both folds to balance asymmetry. Of the 117 original split-face study subjects with moderate to severe NLF, 102 were enrolled in this extended follow-up. During this extension study, treating physicians used the Global Aesthetic Improvement Scale (GAIS) and clinical examination to evaluate subjects at intervals up to 39 months after the last injection of Radiesse. Results: Forty percent of the folds evaluated at least 30 months after the last Radiesse treatment were graded as 'improved' or better on the GAIS. Expectedly, the reported improvement was substantially less at this later time point than had been seen at earlier points in the premarket study, indicating some moderate, sustained improvement in some patients. There were no long-term or delayed-onset adverse events in these 102 patients followed for three years, including no reports of nodules, granulomata, or infections, such as have been reported with certain other dermal fillers. Conclusions: These results demonstrate the long-term safety and effectiveness of Radiesse. Three years after Radiesse injection, no delayed-onset or long-term adverse events were reported. In addition, many patients showed some long-term cosmetic improvement. The durability and safety of Radiesse compare favorably with other injectable fillers

OBJECTIVES/HYPOTHESIS: AlloDerm (LifeCell Corp., Branchburg, NJ) is commonly employed for reconstruction of ablative soft tissue and mucosal defects following surgical resections. Although devoid of growth factors, AlloDerm may serve as an adhesive matrix for binding of growth factors, increasing local angiogenesis, and wound healing. We hypothesized that AlloDerm would enhance angiogenesis and might be altered with autologous blood products to enhance initiation of the angiogenic response. METHODS: We used a human placental vein in a fibrin-thrombin clot-based angiogenesis model. Four groups, human placental vein (HPVM), HPVM with AlloDerm, HPVM with AlloDerm plus platelet-poor plasma, and HPVM with AlloDerm plus platelet-rich plasma were evaluated. Endothelial cell growth was evaluated visually (40x). Hematoxylin and eosin staining and immunofluorescent staining for growth within the AlloDerm matrix were also performed. To assess human umbilical vein endothelial cell (HUVEC) sites of attachment to AlloDerm, we incubated HUVEC cells with AlloDerm for a period of 2 weeks and evaluated attachment with anti-factor VIII immunofluorescence. RESULTS: Angiogenic initiation decreased in the combined placental vein with AlloDerm group (P < .0001 at day 7, 14, 21). Additionally, initiation in the AlloDerm plus platelet-poor plasma group was significantly better than the AlloDerm alone group when placentas 2 and 3 were compared (P < .0001). On hematoxylin and eosin staining and immunofluorescent factor VIII staining, no endothelial growth into the AlloDerm was noted in the samples analyzed. CONCLUSIONS: AlloDerm may be enriched with platelet-poor plasma to stimulate greater initiation and wound healing; however, AlloDerm inhibits angiogenic initiation in this model.

The viability of fat grafts harvested with an established technique after cryopreservation remains unknown. This study was conducted in vitro to evaluate the viability of autologous fat grafts harvested with the Coleman technique and subsequently preserved with our preferred cryopreservation method. Eight adult females were enrolled in this study. In each patient, 10 mL of fat grafts were harvested with the Coleman technique by a single surgeon from the lower abdomen. In group 1, 5 mL of fresh fat grafts were mixed with cryoprotective agents and underwent cryopreservation with controlled slow cooling and fast rewarming. In group 2, 5 mL of fresh fat grafts without cryopreservation from the same patient served as a control. The fat graft samples from both groups were evaluated with trypan blue vital staining, glycerol-3-phophatase dehydrogenase assay, and routine histology. Viable adipocyte counts were found similar in both group 1 and group 2 (3.46 +/- 0.91 vs. 4.12 +/- 1.11 x 10/mL, P = 0.22). However, glycerol-3-phophatase dehydrogenase activity was significantly lower in group 1 compared with group 2 (0.47 +/- 0.09 vs. 0.66 +/- 0.09 u/mL, P < 0.001). Histologically, the normal structure of fragmented fatty tissues was found primarily in both groups. Our results indicate that autologous fat grafts harvested with the Coleman technique and preserved with our preferred cryopreservation method have a normal histology with near the same number of viable adipocytes as compared with the fresh fat grafts. However, those cryopreserved fat grafts appear to have a less optimal level of adipocyte specific enzyme activity compared with the fresh ones and thus may not survive well after they are transplanted without being optimized

Large temple and suprabrow lesions can pose a reconstructive challenge. When the lesion extends anterior to the hairline, esthetically acceptable local flaps may be difficult to design. We describe a modified scalp flap (ie, part Converse scalping flap and part scalp rotation flap) that can be tailored to reconstruct a variety of difficult temple and suprabrow lesions while simultaneously maintaining eyebrow position.The modified scalp flap is raised in a subgaleal plane until approximately 2.5 cm above the brow. At this level, dissection proceeds in the subcutaneous plane to protect the frontal branch of the facial nerve and to keep the flap thin. (The key to the modified scalp flap is the dissection plane change that protects the frontal branch of the facial nerve.) The extent of posterior subgaleal dissection is dictated by the amount of anterior rotation necessary. A temporal dog-ear is removed subfollicularly to permit modified flap rotation and preserve the superficial temporal artery.The modified scalp flap has been used to reconstruct temple and suprabrow lesions in 10 patients ranging in age from 4 months to 22 years. There were no complications. Four typical cases are presented.Temple and suprabrow lesions can be excised and successfully reconstructed in one stage using a modified scalp flap that is extended from the hair-bearing scalp onto the glabrous skin of the forehead. This novel modified scalp flap prevents eyebrow/hairline distortion and avoids facial nerve injury

BACKGROUND: Elbow extension is important for the elbow joint, and it is more difficult to restore with microsurgery than elbow flexion. The purpose of this article is to describe the experience of the authors with elbow extension reconstruction in obstetric brachial plexus palsy patients. The outcomes were analyzed in relation to the type of brachial plexus lesion, timing of surgery, and the type of nerve reconstruction. METHODS: Fifty-five children with obstetric brachial plexus palsy who underwent nerve reconstruction for elbow extension restoration were studied. The mean follow-up period was 6.4 years (range, 2-22 y). Reinnervation of the triceps muscle was accomplished with indirect neurotization of the posterior cord from intraplexus donors or with direct neurotization from extraplexus donors, such as the contralateral C7 and the intercostal nerves. RESULTS: Thirty-seven (67%) of the 55 cases showed good or excellent results (>or=M3+). The average postoperative muscle grading for the triceps was 3.34+/-0.99 compared with 1.19+/-1.29 preoperatively (P<0.0001). Patients with C5 to C7 palsy achieved significantly stronger elbow extension than those with C5 to T1 palsy. In addition, the timing of surgery significantly influenced the final outcome. CONCLUSIONS: Elbow extension is one of big challenges to be restored, especially in obstetric brachial plexus palsy. In early cases (within 6 mo) intraplexus reconstruction of the posterior cord can give excellent results. In later cases, or in cases of multiple avulsions, extraplexus motor donors, which selectively targeted the triceps, can give variable results