Browsing by Subject "mandible"

Now showing 1 - 4 of 4
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    Aerosol and droplet generation from mandible and midface fixation: Surgical risk in the pandemic era
    (Elsevier, 2021-01) Ye, Michael J.; Sharma, Dhruv; Campiti, Vincent J.; Rubel, Kolin E.; Burgin, Sarah J.; Illing, Elisa A.; Ting, Jonathan Y.; Hong Park, Jae; Johnson, Jeffrey D.; Vernon, Dominic J.; Lee, Hui Bae; Nesemeier, B. Ryan; Shipchandler, Taha Z.; Otolaryngology -- Head and Neck Surgery, School of Medicine
    Purpose The COVID-19 pandemic has led to concerns over transmission risk from healthcare procedures, especially when operating in the head and neck such as during surgical repair of facial fractures. This study aims to quantify aerosol and droplet generation from mandibular and midface open fixation and measure mitigation of airborne particles by a smoke evacuating electrocautery hand piece. Materials and methods The soft tissue of the bilateral mandible and midface of two fresh frozen cadaveric specimens was infiltrated using a 0.1% fluorescein solution. Surgical fixation via oral vestibular approach was performed on each of these sites. Droplet splatter on the surgeon's chest, facemask, and up to 198.12 cm (6.5 ft) away from each surgical site was measured against a blue background under ultraviolet-A (UV-A) light. Aerosol generation was measured using an optical particle sizer. Results No visible droplet contamination was observed for any trials of mandible or midface fixation. Total aerosolized particle counts from 0.300–10.000 μm were increased compared to baseline following each use of standard electrocautery (n = 4, p < 0.001) but not with use of a suction evacuating electrocautery hand piece (n = 4, p = 0.103). Total particle counts were also increased during use of the powered drill (n = 8, p < 0.001). Conclusions Risk from visible droplets during mandible and midface fixation is low. However, significant increases in aerosolized particles were measured after electrocautery use and during powered drilling. Aerosol dispersion is significantly decreased with the use of a smoke evacuating electrocautery hand piece.
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    Comparative evaluation of mandibular canal visibility on crosssectional cone-beam CT images: a retrospective study
    (British Institute of Radiology, 2015) Miles, Mahogany S.; Parks, Edwin T.; Eckert, George J.; Blanchard, Steven B.; Department of Periodontics and Allied Dental Programs, IU School of Dentistry
    OBJECTIVES: The purpose of this study was to determine the visibility of the mandibular canal (MC) in CBCT images and if the visibility of the MC is affected by gender, location and/or age. METHODS: CBCT images were evaluated for the visibility of the MC by a board-certified oral and maxillofacial radiologist, a board-certified periodontist and a periodontics resident. Representative slices were examined for the first premolar (PM1), second premolar (PM2), first molar (M1) and second molar (M2) sites by all examiners. The visibility of the MC was registered as either present or absent. RESULTS: 360 total CBCT cross-sectional images were examined, with the MC identified in 204 sites (56%). Age had a significant effect on MC visibility, but it differed by location: for PM1, age 47–56 had lower visibility than age 65+ (p = 0.0377). Gender also had a significant effect on canal visibility, where females had lower visibility than males overall (p = 0.0178) and had the most pronounced difference for PM1 (p = 0.0054). Location had a significant effect on visibility, but it differed by age and by gender: for age 65+, M2 had lower visibility than PM1 (p = 0.0411) and PM2 (p = 0.0180), while for females, PM1 had lower visibility than M1 (p = 0.0123) and M2 (p = 0.0419). CONCLUSIONS: The MC was visualized only in just over half of the CBCT images. Age, gender and location had significant effects on the visibility.
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    The effects of occlusion on single miniplate osteosyntheses of the mandible
    (2017-11) Katona, Thomas R.
    Aim: Miniplate osteosyntheses of a fractured mandible is a complex structural engineering problem that has been modeled experimentally, analytically and numerically. In general, the more realistic the model, the more difficult it is to appreciate its nuances. Thus, a purpose of this paper is to present a basic analytical model that illustrates the most fundamental principles of static equilibrium as it applies to the mechanics of single miniplate osteosynthesis designs. The second purpose is to use the model to demonstrate the effects of changes in occlusion on the loads experienced by the structures. Materials and methods: The 3 equations of static equilibrium were derived from the free-body-diagram of the distal segment of a vertically fractured reduced mandible. The equations were solved parametrically with variations in plate screw locations, anterior-posterior locations of occlusal contact, and occlusal contact force direction, including the simulation of sticky foods. Results: The results indicate a profound effect of occlusal contact force location and direction on the magnitudes and/or directions of the forces acting on the screw and the miniplate, and on the location and magnitude of the interfragmental bone-bone compression force. Conclusions: In some respects, this model is as barebones as is possible. Atypically however, it includes occlusal contact force direction. The results strongly suggest that all analyses of plating systems should account not only for occlusal contact force location and magnitude, but also its direction.
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    EFFECTS OF ORTHODONTIC MINI-IMPLANT DIAMETER ON MICRODAMAGE.
    (Office of the Vice Chancellor for Research, 2012-04-13) Cruz, Enrique; Liu, Sean; Sun, Jun; Blanchard, Steven B.; Soto, Armando; Stewart, Kelton T.; Allen, Matthew R.; Liu, Sean
    Microdamage reduces bone mechanical properties and thus could possi-bly contribute to implant failure. The objective of this study was to investi-gate whether the diameter of mini-implants (MI) affects microdamage gen-eration and whether this differs between the mandible and maxilla due to their contrasting cortical thicknesses. Methods: Maxillary and mandibular quadrants of 5 dogs were randomly assigned to receive, in situ, no interven-tion (control), pilot drilling only, or pilot drilling plus one of three diameters of MI: 1.4 (n=18), 1.6 (n=18), and 2.0 mm (n=18). Microdamage was as-sessed on basic fuchsin stained sections using epifluorescence microscopy. Results: No microdamage was found in the non-drilling controls. Pilot drill-ing produced only minimal microdamage in the maxilla but more microdamage in the mandible. There was significantly higher microdamage generated in the mandible, compared to the maxilla (p<0.05). In the maxil-la, although insertion of all implants produced higher microdamage than the control and pilot drilling, there were no differences between the 3 MI diame-ters. In the mandible, insertion of implants generated significantly higher microdamage than the control, but it did not produce higher microdamage than pilot drilling. Similarly, no differences in microdamage were found be-tween 3 MI diameters. Conclusion: Insertion of MIs in the mandible pro-duced higher microdamage than in the maxilla, which may explain that the higher MI failure rate in the mandible. Implant diameter did not affect over-all microdamage burden in either jaw. Microdamage was mostly generated by pilot drilling through the cortex in the mandible, while microdamage in the maxilla was mainly produced when manual inserting MIs after pilot drill-ing.