Faculty Bibliography

OBJECTIVE:To evaluate the reliability and failure mode of zirconia-reinforced lithium silicate (ZLS) molar crowns of different thicknesses. METHODS:Monolithic ZLS molar crowns (0.5mm, 1.0mm, and 1.5 mm thickness) were modeled and milled using a CAD/CAM system (n = 21/group). Crowns were cemented on dentin-like epoxy resin replicas with a resin cement. The specimens were subjected to single load-to-failure test for step-stress profiles designing. Mouth-motion step-stress accelerated-life test was performed under water by sliding an indenter 0.7 mm lingually down on the distobuccal cusp until specimen fracture or suspension. Use level probability Weibull curves and reliability were calculated and plotted. Polarized-light optical microscope and scanning electron microscope (SEM) were used to characterize fracture patterns. RESULTS:Irrespective of crown thickness, beta (β) values were higher than 1 and fatigue accelerated failures. While 0.5 mm ZLS crowns exhibited a significant reduction in the probability of survival at 200N, 300N and 400 N mission loads (69%, 41% and 19%, respectively), no significant difference was observed between 1.0 mm and 1.5 mm crowns. Both thicknesses have maintained the survivability at approximately 90%. Failure primarily comprised bulk fracture where radial cracks originated from the cementation surface beneath the indenter loading trail and propagated towards the cervical margin. SIGNIFICANCE/CONCLUSIONS:1.5 mm- and 1.0 mm-thickness monolithic ZLS crowns presented higher probability of survival compared to 0.5 mm crowns. Bulk fracture was the chief failure mode, regardless of thickness.

Pain is rated by oral cancer patients as the worst symptom and significantly impairs a patient's ability to eat, talk, and drink. Mediators, secreted from oral cancer microenvironment, excite primary afferent neurons, which in turn generate pain. Oral cancer cells release TNFalpha which induces acute inflammation and nociception in mice. We hypothesize that TNFalpha activates Schwann cells to amplify pain signals. First, we confirmed the involvement of TNFalpha in oral cancer pain in patients and animal models. We found that oral cancer tissues collected from patients have higher TNFalpha concentration compared to anatomically matched normal tissues. Differences in TNFalpha concentration between the tumor and anatomically matched normal tissues correlate positively with total pain scores. In a Nitroquinoline 1-oxide (4NQO) mouse oral cancer model we demonstrated reduced mechanical hypersensitivity (P<0.05, N=8) with the dolognawmeter gnawing assay when TNFalpha was neutralized with C-87. Using a non-contact co-culture model, we found that HSC-3 cells induced a more activated human primary Schwann cells phenotype with increased proliferation (P<0.05) and migration (P<0.05); introduction of C-87 in the co-culture reduced Schwann cell proliferation (P<0.05) and migration (P<0.05) induced by HSC-3 cells. After removal of the co-cultured cancer cells, cancer-activated Schwann cells secrete greater amounts of TNFalpha and nerve growth factor (NGF), another known nociceptive mediator in the oral cancer microenvironment, compared to Schwann cells initially co-cultured with DOK (P<0.05) or naive Schwann cells (P<0.05). To determine whether activated Schwann cells mediate oral cancer pain, we cultured Schwann cells in hypoxic conditions - a known cancer stimulus that induces robust Schwann cell activation. Schwann cell supernatant was then collected and injected into the mouse cheek. Supernatant from hypoxia-activated Schwann cells induced greater facial allodynia (measured with von Frey filaments) in mice (P<0.05, N=7), compared to supernatant from Schwann cells cultured in normoxic conditions (N=5). C-87 significantly reduced facial allodynia caused by hypoxiaactivated Schwann cells (P<0.05, N=5). We infer from our results that TNFalpha plays a role in the activation of Schwann cells and that cancer-activated Schwann cells are a source of nociceptive mediators in the cancer microenvironment. Inhibition of Schwann cell activation might be clinically useful for alleviating oral cancer pain

We sought to investigate the relationship of high life satisfaction with important physical health, mental health, social integration and perceived safety factors among midlife and older Mexican adults. We examined 2,200 midlife and older adults (aged 50-101 years) from the Mexican arm of the Study on global AGEing and adult health (SAGE) and used binary logistic regression models to identify key factors associated with high LSA. Our final logistic regression model revealed self-rated health, affect, interpersonal activities and perceived safety on street to be significantly associated with high life satisfaction. Results from this study add to the nascent literature on subjective well-being of midlife and older Mexicans. Although social work with older adults is not well established in Mexico, researchers and practitioners should collaborate on the development and implementation of social worker-led strategies for prevention and intervention to enhance well-being among midlife and older Mexicans.

Importance/UNASSIGNED:Erich arch bars, 4-point fixation, and bone-supported arch bars are currently used in maxillomandibular fixation, although to what extent they differ in terms of overall charges and clinical outcomes has yet to be reported. Objective/UNASSIGNED:To determine the association of Erich arch bars, 4-point fixation, and bone-supported arch bars in maxillomandibular fixation with hospital charges and clinical outcomes. Design, Setting, and Participants/UNASSIGNED:This historical cohort included 93 patients with mandible fracture who underwent maxillomandibular fixation from January 1, 2005, to June 30, 2015, at a tertiary care center. Statistical analysis was conducted from October 4, 2015, to September 8, 2017. Main Outcomes and Measures/UNASSIGNED:Charge analysis from an institutional perspective, operative time, necessity for a secondary procedure, and postoperative complications. Results/UNASSIGNED:Of the 93 patients in the study (18 women and 75 men; median age, 28.0 years [interquartile range, 23.0-40.0 years]), 27 (29%) received Erich arch bars, 51 (55%) received 4-point fixation, and 15 (16%) received bone-supported arch bars. The mean operative time for Erich arch bars (98.7 minutes; 95% CI, 89.2-108.2 minutes) was significantly longer than for 4-point fixation (48.8 minutes; 95% CI, 41.8-55.7 minutes) and bone-supported arch bars (55.9 minutes; 95% CI, 43.1-68.6 minutes). A total of 17 patients who received Erich arch bars (63%), 37 patients who received 4-point fixation (72%), and 1 patient who received bone-supported arch bars (7%) needed to return to the operating room for hardware removal. Patients who received Erich arch bars and those who received 4-point fixation had significantly higher odds of requiring a secondary procedure than did patients who received bone-supported arch bars (Erich arch bars: odds ratio, 27.1; 95% CI, 2.7-274.6; and 4-point fixation: odds ratio, 42.8; 95% CI, 4.4-420.7). Mean total operative charges for application of the hardware alone were significantly less for 4-point fixation ($5290; 95% CI, $4846-$5733) and bone-supported arch bars ($6751; 95% CI, $5936-$7566) than for Erich arch bars ($7919; 95% CI, $7311-$8527). When secondary procedure charges were included, the mean total charge for Erich arch bars ($9585; 95% CI, $8927-$10 243) remained significantly more expensive than the mean total for 4-point fixation ($7204; 95% CI, $6724-$7684) and bone-supported arch bars ($6924; 95% CI, $6042-$7807). No clinically meaningful difference in complications between groups was found (Erich arch bars, 3 [11%]; 4-point fixation, 5 [10%]; and bone-supported arch bars, 2 [13%]). Conclusions and Relevance/UNASSIGNED:Bone-supported arch bars have comparable complication outcomes, operative time for placement, and overall charges when compared with Erich arch bars and 4-point fixation, and have a lower likelihood of requiring removal in an operative setting.

Primary sternal osteomyelitis (PSO) remains a rare but morbid and challenging condition. Due to the limited reports of PSO in the literature, management of this disease continues to lack consensus. We present a case report highlighting how PSO remained, in our experience, refractory to medical management, and how operative intervention provided resolution, and a review of the literature.

Adenosine receptor activation has been investigated as a potential therapeutic approach to heal bone. Bone has enhanced regenerative potential when influenced by either direct or indirect adenosine receptor agonism. As investigators continue to elucidate how adenosine influences bone cell homeostasis at the cellular and molecular levels, a small but growing body of literature has reported successful in vivo applications of adenosine delivery. This review summarizes the role adenosine receptor ligation plays in osteoblast and osteoclast biology and remodeling/regeneration. It also reports on all the modalities described in the literature at this point for delivery of adenosine through in vivo models for bone healing and regeneration.

INTRODUCTION/BACKGROUND:Myelomeningocele is the most common open neural tube defect. A quadruple rotation-VY advancement flap (butterfly flap) was recently reported for closure of large myelomeningocele defects; however, no series has been reproduced to evaluate this technique. The objective of this study was to describe our experience with this technique. MATERIALS AND METHODS/METHODS:We reviewed all infants born with large myelomeningocele defects who underwent butterfly flap closure over a 2-year period. Demographics, defect size, operative details, and complications were used to generate descriptive statistics. RESULTS:From June 2015 to January 2018, 7 infants met inclusion criteria. Mean defect width was 52% ± 0.11 of the back, representing 21% ± 0.09 of the total back area. Only 1 child had central breakdown. All patients had some peripheral skin dehiscence that occurred on postoperative day 12 ± 7, and these were treated with outpatient wound care. Four patients returned to the operating room for dehiscence electively. There were no incidences of total flap loss. There were no cases of meningitis or myelomeningocele dehiscence. All patients had successful closure of their myelomeningocele without the use of skin grafts. CONCLUSIONS:The butterfly flap is able to close large myelomeningocele defects and has the potential to improve contour. There are minor wound-healing complications, but in the rare event of central dehiscence, quadruple rotation-VY advancement flaps can be re-advanced. In all cases, a large myelomeningocele was successfully reconstructed with robust full-thickness flaps, and there was no need for skin grafting of donor sites.