Faculty Bibliography

PURPOSE: The aim of this study was to evaluate fatigue resistance of dental fixtures with two different fixture-abutment connections by in vitro fatigue testing and in silico three-dimensional finite element analysis (3D FEA) using original computer-aided design (CAD) models. METHODS: Dental implant fixtures with external connection (EX) or internal connection (IN) abutments were fabricated from original CAD models using grade IV titanium and step-stress accelerated life testing was performed. Fatigue cycles and loads were assessed by Weibull analysis, and fatigue cracking was observed by micro-computed tomography and a stereomicroscope with high dynamic range software. Using the same CAD models, displacement vectors of implant components were also analyzed by 3D FEA. Angles of the fractured line occurring at fixture platforms in vitro and of displacement vectors corresponding to the fractured line in silico were compared by two-way ANOVA. RESULTS: Fatigue testing showed significantly greater reliability for IN than EX (p<0.001). Fatigue crack initiation was primarily observed at implant fixture platforms. FEA demonstrated that crack lines of both implant systems in vitro were observed in the same direction as displacement vectors of the implant fixtures in silico. CONCLUSIONS: In silico displacement vectors in the implant fixture are insightful for geometric development of dental implants to reduce complex interactions leading to fatigue failure.

AIM/OBJECTIVE:Persistent socioeconomic disparities in the oral disease burden contribute to pain and suffering among vulnerable and underserved populations who face systemic barriers to access oral health care, including older adults living in disadvantaged urban neighborhoods. The aim of this study is to gain the views of racial/ethnic minority older adults regarding what they believe would support them and their peers in visiting the dentist regularly. METHODS AND RESULTS/RESULTS:Focus groups were conducted and digitally audio-recorded from 2013 to 2015 with 194 racial/ethnic minority women and men aged 50 years and older living in northern Manhattan who participated in one of 24 focus group sessions about improving oral health for older adults. Analysis of the transcripts was conducted using thematic content analysis. The majority of recommendations from racial/ethnic minority older adults to help older adults go to the dentist regularly were centered at the organization and provider level. The preeminence of respectful treatment to racial/ethnic minority older adults may be useful to underscore in oral health programs and settings. CONCLUSION/CONCLUSIONS:There is a need for greater engagement of and attention to patients and other stakeholders in developing, testing, and disseminating interventions to close the gaps in oral health care disparities.

OBJECTIVE/OBJECTIVE:To determine the opinions of healthcare clinicians in the Philippines regarding the 2016 National Pressure Ulcer Advisory Panel (NPUAP) terminology changes and revised staging definitions. DESIGN AND SETTING/METHODS:A survey methodology was used in Manila, Philippines. Convenience samples of healthcare clinicians of varying disciplines and employment settings were invited to participate in this research. INTERVENTIONS/METHODS:A survey was administered at key intervals regarding the revised NPUAP terminology changes and revised staging definitions. The survey was administered before and after an interactive, basic 2-day wound course was conducted. MAIN RESULTS/RESULTS:Results revealed strong support for the 2016 NPUAP terminology change from pressure ulcer to pressure injury and the revised staging definitions. CONCLUSIONS/CONCLUSIONS:Since the NPUAP changed its terminology and revised the staging definitions, the wound care community has been responding to those changes. Because pressure injuries are a global health concern, the opinions of clinicians outside the United States are equally valuable. The healthcare clinicians in the Philippines surveyed appear to embrace the new terminology changes and revised staging definitions put forth by the NPUAP.

PURPOSE: A ceramic and metal abutment prototype was fatigue tested to determine the probability of survival at various loads. MATERIALS AND METHODS: Lithium disilicate CAD-milled abutments (n = 24) were cemented to titanium sleeve inserts and then screw attached to titanium fixtures. The assembly was then embedded at a 30 degrees angle in polymethylmethacrylate. Each (n = 24) was restored with a resin-cemented machined lithium disilicate all-ceramic central incisor crown. Single load (lingual-incisal contact) to failure was determined for three specimens. Fatigue testing (n = 21) was conducted employing the step-stress method with lingual mouth motion loading. Failures were recorded, and reliability calculations were performed using proprietary software. Probability Weibull curves were calculated with 90% confidence bounds. Fracture modes were classified with a stereomicroscope, and representative samples imaged with scanning electron microscopy. RESULTS: Fatigue results indicated that the limiting factor in the current design is the fatigue strength of the abutment screw, where screw fracture often leads to failure of the abutment metal sleeve and/or cracking in the implant fixture. Reliability for completion of a mission at 200 N load for 50K cycles was 0.38 (0.52% to 0.25 90% CI) and for 100K cycles was only 0.12 (0.26 to 0.05)-only 12% predicted to survive. These results are similar to those from previous studies on metal to metal abutment/fixture systems where screw failure is a limitation. No ceramic crown or ceramic abutment initiated fractures occurred, supporting the research hypothesis. The limiting factor in performance was the screw failure in the metal-to-metal connection between the prototyped abutment and the fixture, indicating that this configuration should function clinically with no abutment ceramic complications. CONCLUSION: The combined ceramic with titanium sleeve abutment prototype performance was limited by the fatigue degradation of the abutment screw. In fatigue, no ceramic crown or ceramic abutment components failed, supporting the research hypothesis with a reliability similar to that of all-metal abutment fixture systems. A lithium disilcate abutment with a Ti alloy sleeve in combination with an all-ceramic crown should be expected to function clinically in a satisfactory manner.

PURPOSE: To evaluate the influence of implant diameter in the reliability and failure mode of extra-short dental implants. MATERIALS AND METHODS: Sixty-three extra-short implants (5mm-length) were allocated into three groups according to platform diameter: O4.0-mm, O5.0-mm, and O6.0-mm (21 per group). Identical abutments were torqued to the implants and standardized crowns cemented. Three samples of each group were subjected to single-load to failure (SLF) to allow the design of the step-stress profiles, and the remaining 18 were subjected to step-stress accelerated life-testing (SSALT) in water. The use level probability Weibull curves, and the reliability (probability of survival) for a mission of 100,000 cycles at 100MPa, 200MPa, and 300MPa were calculated. Failed samples were characterized in scanning electron microscopy for fractographic inspection. RESULTS: No significant difference was observed for reliability regarding implant diameter for all loading missions. At 100MPa load, all groups showed reliability higher than 99%. A significant decreased reliability was observed for all groups when 200 and 300MPa missions were simulated, regardless of implant diameter. At 300MPa load, the reliability was 0%, 0%, and 5.24%, for O4.0mm, O5.0mm, and O6.0mm, respectively. The mean beta (beta) values were lower than 0.55 indicating that failures were most likely influenced by materials strength, rather than damage accumulation. The O6.0mm implant showed significantly higher characteristic stress (eta = 1,100.91MPa) than O4.0mm (1,030.25MPa) and O5.0mm implant (eta = 1,012.97MPa). Weibull modulus for O6.0-mm implant was m = 7.41, m = 14.65 for O4.0mm, and m = 11.64 for O5.0mm. The chief failure mode was abutment fracture in all groups. CONCLUSIONS: The implant diameter did not influence the reliability and failure mode of 5mm extra-short implants.

OBJECTIVE/UNASSIGNED:To investigate intrinsic palatal and alveolar tissue deficiency in patients with unilateral cleft lip and palate (UCLP) as compared to age-matched individuals without UCLP using surface area measurements on 3D scans of plaster casts. METHODS/UNASSIGNED:22 maxillary casts of infants with UCLP from the Wyss Department of Plastic Surgery of NYU Langone Medical Center and 37 maxillary casts from infants without clefts from Sillman's longitudinal study were scanned by Ortho Insight 3D by Motion View Software, LLC (Chattanooga, TN) and measured using Checkpoint software (Stratovan, Davis, CA). The palatal and alveolar surface areas of each cast were measured. The most superior point of the alveolar ridge in front of the incisive papilla and the most superior point of each maxillary tuberosity were connected by a line that ran along the highest part of the alveolar ridge. This line was used to set boundaries for the palatal surface area measurements. The surface areas of greater and lesser segments were measured independently on UCLP casts. A total palatal surface area for the UCLP sample including width of the cleft gap was also measured. RESULTS/UNASSIGNED:< .0001). CONCLUSION/UNASSIGNED:An intrinsic palatal and alveolar tissue deficiency exists in patients born with UCLP. The amount of tissue deficiency for a patient with UCLP should be considered when developing and executing a patient-specific treatment plan.

BACKGROUND:Despite the growing success of facial transplantation, organ donor shortages remain challenging. Educational health campaigns can effectively inform the general public and institute behavioral modifications. A brief educational introduction to facial transplantation may positively influence the public's position on facial donation. METHODS:The authors anonymously surveyed 300 participants, gathering basic demographic information, donor registration status, awareness of facial transplantation, and willingness to donate solid organs and facial allografts. Two-hundred of these participants were presented an educational video and subsequently resurveyed on facial donation. Factorial parametric analyses were performed to compare exposure responses before and after watching video exposure. RESULTS:Among participants completing the survey alone (control group), 49 percent were registered donors, 78 percent reported willingness to donate solid organs, and 52 percent reported willingness to donate facial allograft. Of participants who watched the video (video group) 52 percent were registered; 69 and 51 percent were willing to donate solid organs and face, respectively. Following educational intervention, 69 percent of participants in the video group reported willingness to donate facial tissue, an 18 percent increase (p < 0.05), that equated to those willing to donate solid organs. The greatest increase was observed among younger participants (23 percent); women (22 percent); Jewish (22 percent), Catholic (22 percent), and black/African American (25 percent) participants; and respondents holding a higher degree. No significant differences according to gender or ethnicity were observed. CONCLUSION/CONCLUSIONS:Educational interventions hold much promise for increasing the general public's awareness of facial transplantation and willingness to participate in donation of facial allografts.