The fenestrations found on the vertical part of the maxillary bone of the order Lagomorpha are a defining trait of the order, and yet the function and evolutionary benefit is not well understood. The only study on the function of the fenestrations was by Moss and Feliciano, in 1977. They concluded that the "fenestrations are causally related to the normal lack of transmission of masticatory forces through the vertical plate." Here we argue that this conclusion is incomplete. Lack of masticatory forces in tooth bearing structures of many animals does not result in the pattern of fenestrations observed in lagomorphs. Even toothless mammals have intact maxillary bones. Using gross observational studies of skulls, imaging software, specimens treated with vascular fill agent, and histology, we suggest an additional function, specifically thermoregulation. The primary evidence is the proximity of the nasal cavity, which is exposed to ambient air, coupled with large blood vessels. Especially because rabbits are obligate nose breathers, these conditions suggest that this region of the skull serves to dissipate body heat to the environment. 

Cone-beam computed tomography (CBCT) has been one of the newest innovative technologies introduced in the field of dentistry, and its role in diagnostic imaging has been greatly beneficial for patients in need of various treatment. The goal of this study is to utilize CBCT to investigate the effects of experimental periodontitis on molar roots and alveolar bone in a pig model by taking quantitative measurements from 3D models. Four normal pigs and eight with experimental periodontitis pigs were included in this study. Experimental periodontitis was induced by periodic inoculation with 4 types of periodontal bacteria, along with the suture ligature around the upper third deciduous molar for 8 weeks. Two sets of CBCT were taken for each experimental pig before and after the induction of periodontitis, but one set for control pigs. A custom-made seat was placed on the CBCT chair for CBCT scanning while the pig was intubated with 3% isoflurane. Obtained CBCT images were then used to create 3D models using the software ITK-Snap with the aid of Invivo5. Models were standardized by the region of interest selected for segmentation. Volumetric measurements were taken in the software. The volumes of molar roots and alveolar bone were then compared in the experimental and control pigs before and after the induction of periodontitis. The expected results should show significant volumetric reduction in the alveolar bone of the experimental pigs as compared with controls. Further in the project, the expected results should show that there is significant reduction in the volume of the roots as well. Understanding the use of CBCT and its role in 3D modeling and quantitative measurement will contribute cutting-edge treatment planning and diagnostic methodologies for all dental practitioners. 

Periodontitis is a serious infection that damages both soft (gingiva and periodontal ligaments-PDL) and hard tissues (dental cementum and alveolar bone) of the periodontium. Mineralization is an essential dynamic process for development and maintenance of the periodontium. The current study focuses on how mineralization of alveolar bone and the attachments of PDL are affected by experimental periodontitis in a pig model. Eight three-month-old pigs were periodically inoculated with 4 types of periodontal bacteria, along with a ligature around the last maxillary deciduous premolar for 8 weeks to induce periodontitis. Another group of 7 pigs without the ligatures and bacterial inoculations were taken as control. Bone labeling dyes, calcein and alizarin, were injected intraperitoneally 7 and 2 days respectively before euthanasia. The harvested upper molar blocks were embedded in micro-bed resin and successive sections were taken at 30μm thickness coronally. Three sections that contained the most intact mesial and distal roots of the target molar were selected and examined under epifluorescence. The interlabel distance between two vital markers at the surfaces of alveolar socket and trabeculae, cementum, and the attachment of PDL fiber bundles were measured, and the mineral apposition rates (MAR) were calculated. Preliminary results indicate that, as compared with control pigs, periodontitis pigs showed reduced MAR in the trabecular structures, more significantly in the regions underneath the molar furcation. The reduced MAR was also seen in the alveolar ridges in the periodontitis pigs but was not as significant as the region under the furcation. More data analysis is currently underway. These results suggest that experimental periodontitis may slow down periodontal mineralization in young growing pigs, in which alveolar bone underneath the root furcation and the cortical layer of the socket are mostly affected.

Traumatic dental injury (TDI) is an important public health issue in the pediatric population. Patient demographics, hospital characteristics, and diagnoses present with TDI visits to emergency departments in the United States are poorly understood. The objective of this study was to provide nationally representative estimates of hospital-based emergency department (ED) visits for broken teeth and loss of teeth due to trauma in patients 21 years old and younger. Nationwide Emergency Department Sample (NEDS) for the year 2012 was used. All hospital-based ED visits occurring among 21-year-olds and younger with an International Classification of Diseases-Clinical Modifications, volume 9 code for broken or loss of teeth due to trauma were selected for analysis. Hospital and patient characteristics and external causes of injury were examined. In 2012, hospital-based ED visits with a dental injury diagnosis comprised an estimated total of 66,656 (0.18%) of all ED visits among 21-year-olds and younger in the United States. Of these, 64,732 (97%) had a diagnosis of broken teeth and 2,132 (3%) had loss of teeth due to trauma. Medicaid was the primary payer for 44% of dental injury ED visits. The majority (72%) of the total ED visits that had a diagnosis of dental injury were accompanied with other diagnoses. Of the dental injuries with at least one concurrent diagnoses, 42% were open wound to head or face, 10% were accompanied with facial fracture(s), and 4% had a concomitant diagnosis of concussion. Among specified causes of injury, "fall" and "struck by; against" were the most frequently reported causes of TDI (47% and 30%, respectively). The primary mechanism of injury in children 6 years of age and younger were falls as compared to middle and late adolescent age groups examined. Hospital-based ED visits that had a dental injury were rarely reported, and often accompanied with other diagnoses.