Accessory Mental Foramen, an Anatomical Variant of Mental Foramen

Accessory Mental Foramen, an Anatomical Variant of Mental Foramen, Detection Using Cone Beam Computed Tomography Introduction: Numerous anatomical variations are reported in the literature in the mandibular region along the course of the mandibular canal and at the mental foramen region. Literature review showed presence of accessory mental foramen (AMF) in some populations, and its importance and prevalence in our population due to its clinical implications. On two dimensional images it may be confused for periapical or periodontal pathology, or being unaware of its presence may pose complications during periapical surgeries, implant placements or orthognathic surgeries in the surgical access line of the mandible. Literature shows incidence of AMF to be around 1.5 to 10 % in various populations, often missed in conventional radiography. Imaging by cone beam computer tomography (CBCT) is far more accurate and superior than conventional radiography. Aims & objectives: Retrospective analysis of CBCT volumes done to 1. Check for presence of accessory mental foramen 2. Location of AMF in relation to mental foramen 3. Unilateral/ bilateral occurrence of AMF 4. Distance of AMF from 1st and 2nd premolar root tips Materials & methods: Cone beam CT volumes acquired using i-CAT™ between January.01.2011 and Dec.31.2016 were selected to be viewed according to the selection criteria. All HIPAA identifiers were removed and the DICOM volumes were evaluated using Anatomage®, Invivo 6 a third party software. IRB approval was obtained prior to the start of the study. Initially, the course of mandibular canal was outlined by tracing the canal. Mental foramen identified and its distance from base of mandible were measured. The axial sections were measured at an interval of 0.5mm, and the parameters for cross section were with a width of 40mm, interval of 1.5mm and thickness of 2.0mm The Axial slice indicator was placed on the top of the foramen and was used as a reference point for all measurements to prevent inter examiner variability. Conclusion: Presence of accessory mental foramen were looked for and if present, the distance between mental foramen and AMF were measured and its position in relation to mental foramen are described as superior/ inferior/ buccal/ lingual to mental foramen. Lower Rates of OMS Resident Personal Achievements May be Related to Increased Levels of Anxiety during Training Purpose: Anxiety is remarkably prevalent among medical residents in training and is often associated with fatigue, psychological dysfunction, and burnout. Personal achievement is a characteristic of burnout, which, if unaddressed, may lead to medical error, and decrease in the overall quality of patient care. The purpose of this study is to determine the prevalence of anxiety in association with the level of perceived personal achievement in Oral and Maxillofacial Surgery (OMS) residents. Materials and Methods: An anonymous 20question cross-sectional online survey was developed using the anxiety component of the Hospital Anxiety and Depression Scale (HADS-A) and the personal achievement component of the Maslach Burnout Index (MBI). The survey was sent to all the OMS residents enrolled in programs affiliated with the American Association of Oral and Maxillofacial Surgery in 2017. Univariate and bivariate analyses were conducted to obtain summary measures of the predictor (anxiety) and the outcome (personal achievement) stratified by age, gender, marital status, program type (4 year/ 6 year), and year of residency. Multinomial logistic regression models were obtained to evaluate the association of anxiety to personal achievement. A 2sided P value less than .05 was considered statistically significant. Results: Two hundred thirty eight responses were received (20% response rate); 80% of respondents were men (n= 189), 60% were above 30 years of age (n=138), 46% were unmarried (n=109), and 56% were enrolled in a 4-year program (n= 134). 58% of respondents had moderate to severe levels of anxiety. 49% had low to moderate levels of personal achievement. Women were more likely to have severe anxiety compared to men (60 vs. 37%; P < 0.01). Residents with severe anxiety were 91% more likely to report low levels of personal achievement compared to residents with low anxiety (OR= 0.09; 95% CI= 0.03-0.22; P < 0.0001). Significant inverse relationship between personal achievement and anxiety has been detected where the odds of achieving high personal achievement scores decreases significantly as the severity of anxiety increases. Conclusion: More than half of OMS residents in the US report moderate to severe anxiety. Higher levels of anxiety are associated with lower personal achievement levels. It is important to understand the negative impact that anxiety has on residents, including the unintended consequences. The Relationship Between Early Childhood Caries and Food Insecurity, Using NHANES 2013-2014 Objective: Access to affordable and nutritious foods is a significant public health concern, and research has found food insecurity to be related to a poorer health outcomes in both adults and children. Early Childhood Caries (ECC) is a highly prevalent disease in children under six years of age, and disproportionately affects minorities and low SES groups- groups which exhibit increased utilization of social services and programs such as food assistance programs. This study seeks to examine the relationship between Early Childhood Caries and food insecurity using data from the 2013-2014 National Health and Nutrition Examination Survey (NHANES). Methods: Cross sectional data analysis utilized demographic, oral health exam and food security questionnaire data from NHANES 2013-2014. The following items from the NHANES 2013-2014 survey were used as measures of food security: “Worried run out of food”, “Food didn’t last”, “Household food security category”, “Emergency food received”, “Ever received food security benefits”, and “WIC benefit received in the last 12 months”. Results: In the sampled population, 19.7% of participants had ECC as defined by the AAPD. After adjusting for age, gender, ethnicity, and family income, “Emergency food received” and “Ever received food security benefits” were found to be significantly associated with ECC. Participants who indicated have had “Emergency food received” had 2.9 times the odds ECC than their counterparts who had not received emergency food (95% CI: 1.3-6.6,P=0.010). Additionally, those who indicated having “Ever received food security benefits” had 1.9 times the odds of those who indicated they had never received benefits (95% CI: 1.3-2.8, p=0.0009). Conclusion: Taken together with existing research, the results of this study indicate that future research and intervention should focus on targeting populations that utilize food assistance programs to also address oral health concerns. Understanding Pathologies Associated with Deficient LATS1/2 Kinase in Salivary Glands Objectives: The salivary gland epithelium lines a complex network of branched ductal tubes that end in acini, which together produce, transport and secrete saliva. The development and homeostasis of the salivary epithelium requires the precise coordination of a multitude of signals, many of which are poorly understood. Our prior studies have indicated that the nuclear activity of the transcriptional regulator Yap, a key effector of the Hippo pathway, is critical for the patterning of Krt5/Krt14-positive progenitors in the developing submandibular gland (SMG). Further, exclusion of Yap from the nucleus, which is mediated by the Lats1 and Lats2 (Lats1/2) kinases, is essential for the developmental maturation of the ductal epithelium. We therefore hypothesized that the Lats1/2 kinases play a critical role in the homeostasis of the adult salivary gland. To test this, we conditionally deleted Lats1/2 in mature luminal epithelial cells in mouse SMG ducts. Methods: Conditional deletion of the Lats1/2 genes was achieved by crossing Krt8-CreERT2 mice with Lats1/2 loxP/loxP mice. Lats1/2 knockout was achieved in 12-week-old female mice following tamoxifen treatment. Paraffin-embedded sections of Lats1/2 deleted (Lats1/2-cnull) SMGs were compared to age- and sex-matched tamoxifen-treated controls (CON) using immunohistochemistry analyses. Results: Lats1/2-deleted SMGs exhibited prominent morphological alterations with an apparent loss of acinar morphology, disorganized ductal structures, and stromal disorganization. Increases in proliferative Ki67+ ductal epithelial cells were also observed, along with an interstitial accumulation of CD45+ lymphocytes. Conclusions: SMGs of Lats1/2-cnull mice exhibited abnormal morphology resembling diseased salivary gland epithelium, including features similar to those found in Sjogren’s Syndrome. Further analysis of the Lats1/2-deleted mouse model will guide a better understanding of salivary gland pathologies, which will hopefully offer new opportunities for development of early diagnosis or targeted treatment interventions. Volumetric Changes in the Nasal Cavity after Minimally Invasive Sinus Technique Background: Before the advent of endoscope assisted/guided surgery, correcting abnormal sinus anatomy historically involved invasive procedures like the Lothrop, CaldwellLuc, etc. Over the last decade, Minimally Invasive Sinus Technique (MIST) has been suggested as a targeted and non-invasive anatomically based reproducible approach towards restoring/ removing sinus obstructions. Aim: To evaluate the efficacy of minimally invasive sinus technique in improving airway volumes and thus improving the airflow for young children and adolescents suffering from compromised airway. Method: In this prospective cohort study, 17 patients with compromised airway (9 males and 8 females) underwent MIST surgery to open and connect the nasal cavity with the agger nasi, anterior and middle ethmoidal sinuses. CBCT scans were taken pre and post-surgery. Using Mimics software for 3D reconstruction and integrated cephalometric analysis, the scans were analyzed to measure the difference in airway volumes. Results: Significant increase in the nasal cavity volumes was found after surgery in 15 of the 17 patients. 2 patients showed evidence of synechiae (inflammation of the sinus and nasal soft tissues) in the post surgical scan, thereby showing a contrasting decrease at post surgical evaluation. The t-test values for the pre and post surgical comparison groups were as follows: Significance (P) – 0.0008 Pre Surgical group: Mean – 9517.47, Standard Deviation (S.D.) – 3108.74 Post Surgical group: Mean – 12648.76, Standard Deviation (S.D.) – 4297.55. Conclusion: Minimally Invasive Sinus Technique as used for this surgery has immense potential in its application as a novel approach for improving the airway flow and can be used in conjunction with orthodontics when necessary to improve overall quality of life. Ductal Tree Patterning during Branching Morphogenesis of the Submandibular Gland Background: The development of ductal structures during branching morphogenesis relies on signals that specify ductal progenitors to set up a pattern for the ductal network. Methods: Here, we identify cellular asymmetries defined by the F-actin cytoskeleton and the cell adhesion protein ZO-1 as the earliest determinants of duct specification in the embryonic submandibular gland (SMG). Apical polarity protein aPKCz is then recruited to the sites of asymmetry in a ZO-1-dependent manner and collaborates with ROCK signaling to set up apical-basal polarity of ductal progenitors and further define the path of duct specification. Results: Moreover, the motor protein myosin IIB, a mediator of mechanical force transmission along actin filaments, becomes localized to vertices linking the apical domains of multiple ductal epithelial cells during the formation of ductal lumens and drives duct maturation. Conclusion: These studies identify cytoskeletal, junctional and polarity proteins as the early determinants of duct specification and the patterning of a ductal tree during branching morphogenesis of the SMG Cell Free Circulating Tumor DNA Mutation Profiling of a Colorectal Carcinoma Patient by Next Generation Sequencing for Guidance in Identifying Drug Options, Novel Mutations and Personalized Treatment-Case Study Background: Traditional cancer treatment follows standard drug regimens for all patients with similar types of cancer and metastases. However, recent development of the DNA sequencing technologies and databases reveals that there are more complex mutations in similar cancer types. Therefore, patient specific, personalized cancer treatments have gained importance. However, identifying mutations is not easy in clinical settings because a needle biopsy is often not optimal and applicable to all cancer patients. Collection of tumor samples by needle biopsy is also challenging; tumor cells mixed with normal cells can result in misinterpretation of the frequency of mutations. Method: To obtain high-quality samples of tumor DNA and to generate a less invasive sampling, I implemented a blood-based technique to collect cell free circulating tumor DNA (cfct-DNA) for further mutation analysis and personalized treatment options. For example, I performed the Ion AmpliSeq-Next Generation Sequencing based diagnostic test (IA-NGS) with a customized gene panel of 409 tumor suppressor/oncogene related genes on ctcf-DNA samples of a cancer patient. The overall sensitivity of the test is high with respect to SNP, MNP, DEL, INS mutations. Results: In particular, high frequency (100-20 %) 3049 mutations in 369 genes were identified for a colorectal carcinoma patient. 880 mutations in 278 genes are cancer driving mutations and 850 mutations on 260 genes are novel mutations that were reported for the first time. Further, driver DNA mutations were utilized to predict affected-downstream protein sequences and their dysfunctions by matching DNA mutations with their protein localizations. To identify appropriate treatment options, more than 500,000 potential compounds were scanned from databases to overlap with matching known cancer pathways and treatments that include hormone therapies, signal transduction inhibitors, gene expression modulators, apoptosis inducers, angiogenesis inhibitors, immune enhancers and heat therapy options. Primary and secondary treatment options were identified for targeted therapy for the colorectal cancer patient. For initial study, the treatment efficacy was monitored by PET-Scan after 12 weeks of recommended therapy. Conclusion: Overall, the high sensitivity and less-invasive NGS based cfct-DNA mutation profiling demonstrated the feasibility of detection of actionable alterations and potential new drug targets in a patient's mutation profile. This approach is also applicable to maximize efficiency of targeted therapy options for improving quality of care for cancer patients. Public Housing Community Member Perspectives on Biomedical and Behavioral Research Objectives: Understanding participant perspectives about research, particularly those of racial minority populations, is essential to the success of community-based studies conducted in public housing or other low-income communities. There is little to no research pertaining to participant understanding of biomedical versus behavioral research in these vulnerable and historically exploited communities. Thus, the goals of this study are to gain insight into (1) participant understanding of biomedical research versus behavioral research, (2) facilitators and barriers to participation in biomedical versus behavioral research, and (3) whether the kind of research provider affects the decision to participate in a study. Knowledge gained from this study may affect the design and application of community-based interventions that promote health among economically disadvantaged communities. The hypotheses of this study are that (1) public housing community members (PHCM) have a better understanding of biomedical research when compared to behavioral research, (2) the facilitators and barriers to participation will be the same for biomedical and behavioral research, and (3) PHCM are more likely to participate in studies if the research provider is familiar to the subject. Methods: PHCM perspectives about research were assessed via a 90-question quantitative anonymous survey administered to public housing residents 18 years or older. 266 surveys were collected at Boston Public Housing events throughout the city. Results: Results show that PHCM believe they have a better understanding of behavioral research compared to biomedical research. Subjects who had participated in a behavioral clinical trial (TSHS) were better able to categorize the study as behavioral or biomedical when compared to subjects who were not enrolled in TSHS. Nevertheless, 52% of the TSHS-enrolled subjects were not able to correctly categorize TSHS clinical trial as behavioral. Results also show no variance between the factors that facilitate and interfere with participation in biomedical research when compared to behavioral research studies. In addition, the first and second most likely research provider to convince PHCM to participate in both biomedical and behavioral research studies respectively is their own doctor and their own dentist. While the first and second least likely research provider to convince PHCM to participate in both biomedical and behavioral research studies respectively is a drug company and an insurance company. Conclusions: It is unclear whether PHCM have a better understanding of biomedical research than behavioral research. Additionally, it has been shown that the factors that affect PHCM participation are the same regardless of the type of research study—biomedical or behavioral. Finally, PHCM are more likely to participate in community-based research studies if the study is managed by someone familiar, such as their doctor or dentist. Early Detection of Oral Cancer: A Dental Responsibility Introduction: Oral cancer being the sixth most common cancer worldwide is making it a global concern. Delay in diagnosis of Oral Cancer has claimed thousands of lives and continues being a rising threat. Indian subcontinent accounts for one-third of the world’s oral cancer burden with the highest incidence of smokeless tobacco use. United States inspite of being in better state of health shows a rising mortality attributed to oral cancer. Therefore, the need for the prevention and implementation of effective treatment measures are of utmost importance. Objectives: Our goal is directed towards developing a better teaching model that targets an interdisciplinary approach as developed in other branches to give a greater exposure before stepping in the real world outside. It entails on refining our diagnostic skills and identifying better ones which ensure a thorough evaluation and identification of early signs and symptoms of oral cancer. Methods: This is a literature review based on descriptive and statistical analysis. A broad collection of 18,285 articles was narrowed down to 108 articles through comprehensive screening and using accurate MeSH terms. A detailed evaluation of 22 relevant articles that were pertinent to our research topic were narrowed down. These articles focused on knowledge of dental students and dentist on early signs and symptoms of oral cancer, public awareness about their oral health as well as the referral and treatment protocols taken. Results: Studies have shown that most general dentists are quite adequate in identifying only smoking as well as alcohol as a risk factor for oral cancer. Most dentists find themselves comfortable in identifying only ulcers followed by leukoplakia as a form of oral cancer. Moreover ulcerations were the most common and recognizable form of disease. Conclusion: In India, there are additional unique risk factors that are strongly associated with oral cancer. They include: betel quid and areca nut chewing. Betel quid and areca nut chewing are of unique importance because they cause oral submucous fibrosis (OSMF). Other limitations to identifying OC signs were lack of knowledge and awareness amongst patients who presented quite late for a dental checkup. Assess the Correlation among International Dentists with a Specialty Dental Degree from Outside North America with Performance in a Course Related to that Specialty in the Advanced Standing Program Introduction: In the academic year 2015-16, sixty percent of US dental schools admitted a total of 533 internationally trained dentists into a two year DMD or DDS advanced training program. Boston University Henry M. Goldman School of Dental Medicine (BUGSDM) twoyear training program for foreign trained dentists is called the Advanced Standing (AS) program which admitted 83 students in the 2015-2016 academic year. It is common for first year AS students to enroll in the program after completing a specialty degree outside of North America or additional training, such as a master’s degree in the US. Regardless of their previous experience or specialty training outside of North America, few exemptions are made for courses relating to previous specialty training outside of the US. The variability in teaching protocols and grading systems from around the world make it extremely hard for dental schools to allow exemption of courses for foreign trained specialists. Currently, there is no information on whether AS students with a specialty degree perform better in a course pertaining to that specialty compared to their peers. Aims: The overall objective of our study was to understand if there is a correlation of performance by an international dentist with a specialty degree from outside North America to a final grade in a course pertaining to that specialty in the AS program. Our secondary objective was to understand if the performance in a course pertaining to that specialty is specific to a certain country or region. Methods: A Fourteen question survey with both open and close ended questions with branching logic was developed and administered to Advanced Standing class of 2018 at BUGSDM electronically via Qualtrics. Data was entered and imported into Microsoft Excel from Qualtrics. Descriptive statistics were calculated using Microsoft Excel. Results: Students with a specialty degree,33.3 % found the pre-clinical course neither hard nor easy and 20% found it to be slightly difficult and 20 %found it moderately easy. 60 % of the students with specialty training spent 0-4 hours practicing for the pre-clinical course relating to their specialty which was similar to students with 2-5 yrs experience (58.3%) and students with >5 years’ experience (50%) while students with <2 years’ experience, 37.03 % spent 0-4 hours and 29.6% spent 5-8 hours. Conclusions: Students with a specialty degree self-reported a grade of A/A- in the course relating to that specialty. Regardless of previous education, specialty or work experience, students in the AS program suggest that pre-clinical courses require practice and effort to excel. Data collected from this survey suggests that the Advanced Standing curriculum at BUGSDM should be standard for all students regardless of prior experience outside of the US. Data collected from this survey suggests there is no co-relation to performance in a course pertaining to the specialty is specific to a certain country or region. Transforming E. coli and Bacillus with Plasmid Encoding Gluten-degrading Enzymes Background: Celiac disease, one of the most common diseases worldwide, is characterized by a life-long gluten sensitivity accompanied by an auto-immune reaction. Gluten-degrading enzyme Rmep have been isolated from Rothia mucilaginosa, a natural colonizer of the oral cavity. Like nattokinase, Rmep degrades an immunogenic ⍺-gliadin peptide and has important implications as enzyme therapy for celiac disease patients. Objective: To initiate transformation of E. coli and B. subtilis with plasmids encoding gluten-degrading enzymes: Rmep isolated from R. mucilaginosa, and nattokinase from B. subtilis. Materials and Methods: Plasmids pHT43Rm encoding Rmep and pHT01-Bs encoding nattokinase were used for the transformations, with pUC19 as a control. E. coli DE3 and B. subtilis WB800N were used as competent cells. E. coli DE3 cells were first transformed with pUC19 and pHT01-Bs by heat shock. B. subtilis WB800N were transformed with pHT43-Rm, pHT01-Bs and pUC19 by heat shock and by following conventional electroporation protocol. IPTG induction and AAPF cleavage test were conducted to examine endogenous and secreted nattokinase activity in transformants. Results: Following heat shock using pUC19 and pHT01-Bs, transformation of E. coli was achieved and the transformed cells grew abundantly on LB-Amp plates, although expression was not induced by IPTG and AAPF cleavage activity was not detected. This may be attributed to E. coli’s lack of cellular machinery for protein processing. B. subtilis WB800N subject to both heat shock and electroporation grew on LB plates but did not grow on LB-Amp plates, demonstrating unsuccessful transformation using conventional methods. Conclusion: E. coli DE3 was successfully transformed with pUC19 and pHT01-Bs by heat shock. Yet, conventional electroporation methods for B. subtilis WB800N require further optimization. Potential modifications include adding trehalose in the electroporation media while applying a stronger pulse. Osseointegration in Piezoimplants Versus Cylindrical Implant Introduction: Dental implants can successfully restore edentulous areas but current surgical techniques are inadequate in areas lacking sufficient bone volume. Piezoelectric surgery has shown encouraging effects on hard and soft tissue healing and when splitting narrow alveolar ridges to place cylindrical implants. A new wedge-shaped titanium "Piezoimplant" requires piezoelectric osteotomy. This study measured osseointegration and alveolar ridge changes comparing "Piezo-implants" and conventional threaded cylindrical implants. Methods: After 3 months post-extraction, 18 conventional cylindrical implants (Nobel Active, Nobel Biocare®) and 18 wedge-shaped "Piezo-implants" were placed using a splitmouth design in 3 minipigs (n = 36). The cylindrical implant sites were prepared with rotary instrumentation while the "Piezo-implant" sites were prepared using piezoelectric surgical inserts and the corresponding implants were placed. Quantitative microcomputed tomography analysis (Scanco Medical®) assessed peri-implant alveolar bone volume and osseointegration. Histologic and histomorphometric measurements evaluated periimplant healing and bone-to-implant contact. Submicron x-ray imaging determined bone structure along the implant surfaces. Results: A multiple linear regression model with Rsquare of 0.69 demonstrated a significantly higher BV/TV in the mandible (t ratio = 6.21, p < 0.01), significant increase of BV/TV over time (t ratio = 5.21, p < 0.01), and significantly higher average BV/TV in "Piezo-implants" than the cylindrical implants (t ratio = -2.38, p < 0.01). Histological sections demonstrated that "Piezo-implants" had a greater % BIC at 4 and 12 weeks, a greater percent new bone growth within the ROI at all three time points, and a slight increase in bone maturation at 12 weeks when compared to the cylindrical implants. Highresolution x-ray microscopy exhibited a tighter interface between implants and alveolar bone formation in the "Piezo-implants". Conclusion: Bone formation increased significantly over longer healing periods, was greater in the mandible compared to the maxilla, and higher in the "Piezoimplant" group. "Piezo-implants" had a more desirable healing and may be suited for narrow ridge spaces without additional ridge augmentation. Thus, the novel wedge-shaped "Piezo-implant" system should be considered a viable option in cases with narrow alveolar bone. Further research is needed to establish clinical validity. Lay People’s Preference for Smile Esthetics Following Orthodontic Treatment Objectives: To evaluate how certain visual extra- and intraoral smiling variables influence laypeople’s preference for a step or no step between the incisal edges of the maxillary central and lateral incisors in orthodontically treated patients, and how subject demographics may modify such an association. Results may yield clinical implications that could assist in orthodontic treatment planning. Methods: Sixteen cropped, smiling photographs with differing esthetic variable combinations for skin pigmentation, lip thickness, amount of gingival exposure, and tooth length were duplicated and placed in a presentation, with one duplicated pairing per slide. One of the duplicates was modified utilizing a photograph editing software (Photoshop CS6) to create a 1mm step between central and lateral incisors, and the other had no step. Photos were shown to 200 laypeople, and they were asked to choose which smile they prefer for each pairing. Chi-square test and logistic regression analysis were performed using SAS. Results: More college-educated people (63%) were surveyed than people who did not attend college. For ten out of sixteen esthetic categories, people preferred no step as compared to step. Age and smile esthetic preference are not independent for categories eight, nine, eleven and sixteen. Gender and smile esthetic preference are not independent for category five. Race and smile esthetic preference are not independent for category seven. Education and smile esthetic preference are not independent for categories four and sixteen. Conclusions: The results suggest that more people prefer no step between maxillary central and lateral incisors as compared to a step, and that patient background and demographics have little-to-no influence on this preference. Defining Hard and Soft Tissue Asymetry Using 3-Dimensional CBCT Analysis Objectives: The aim of the study is 1) establish appropriate, reproducible soft tissue landmarks and a bony counterpart in CBCT images 2) evaluate the correlation between the skeletal and soft-tissue landmarks 3) use the measurement correlations to objectively define asymmetry. By determining these measurement correlations between hard and soft tissue landmarks, we can discover where asymmetries originate. This will provide a set of data that can be used as reference for future studies. Materials and Methods: Pre-treatment Cone Beam Computed Tomography (CBCT) films of 160 esthetic human subjects previously used by another investigator were screened for use in our current research. These DICOM files were imported into InVivoDental5.3 software (AnatomageTM; San Jose, Calif.) for screening and 60 CBCT scans were selected for analysis. A soft tissue mask was created on all scanned images, establishing hard and soft tissue reconstructions. 17 anatomic bony and soft tissue landmarks were identified on each scan in reference to coronal, sagittal and horizontal planes. The reference planes were defined as Nasion, the most posteriorly identifiable point on the fronto-nasal suture line (x), Midpoint of Clinoid Processes (y), and the most inferior point of the inter-maxillary suture, as located between the central incisors (z). Each landmark was given an x-, y- and z- coordinate representing its three dimensional position and bilateral linear measurements to the reference planes were recorded. Ratios were then established between the soft tissue point and bony tissue counterpart in all three planes. InVivoDental5.3 software was used to calculate linear distances between each landmark and the reference planes. Descriptive statistics of our sample and correlation analyses were performed. The mean average and standard deviation of each hard and soft tissue landmark was calculated. Also, the correlations between the respective hard and soft tissue landmarks were calculated. Results: A comparison between the hard and soft tissue landmark means was accomplished with the use of paired t-tests with a 5% significance level, or p value of 0.05. It was founded that hard and soft tissue landmarks do have positive correlations, but four landmarks existed which showed statistical difference in location relative to the reference planes (p<.0.05). Conclusion: The trend of the data indicates a significant relationship between the soft and hard tissue points in three-dimensional images. The skeletal and corresponding soft tissue landmarks, which were statistically significant, could be due to tracing error, given the indiscrete location of some of the landmarks. However, these results could lead further researchers to use this information to discover the reasons behind the location differences, and start to define where asymmetries initiate in the skeleton and overlying facial soft tissue. Retention Load of Various Ceramics and Cement Combinations to Titanium Objectives: The purpose of this in vitro study was to assess the retention load of composite resin cements between titanium and various ceramic materials. Methods: A titanium pin (Grade V Ti alloy, 6.4 mm high, 8.2° taper) was scanned using the Sirona Inlab scanner software version SW4.2.5. A crown (tooth #19) was designed to fit the pin and machined using four crown materials (Ivoclar e.max, Vita Enamic, Vitablocs Mark II, and Sirona inCoris zirconia). Pins were held in a CNC machine to reproducibly sandblast each pin at the same speed and pressure (100 psi, Prepstar) using 125 micron alumina and then cleaned in an ultrasonic bath. The milled crowns were cemented to the pins using three different cements (3M/ESPE RelyX Ultimate, Ivoclar Multilink Hybrid, and Kuraray Panavia VF). A load of 1190 grams was placed on the crowns to achieve uniform cementation. Two techniques were used for each cement, one with no treatment (no primer/no etch) and the other with treatment as recommended by the manufacturer (primer/etch). DOE was used to determine the testing sequence and the specimen number. A pull out test was applied on all specimens using a universal mechanical testing machine (Instron 5566A) at a crosshead speed of 1mm/min. Load at failure was recorded for each specimen. Data were analyzed by factorial regression model using JMP Pro 13. Results and Conclusions: Overall retention load values were lowest for zirconia and highest for e.max and Enamic. In general, primer/etch technique produced significantly higher values than no primer/etch. For RelyX cementation, no primer/etch produced significantly higher retention. Maximized desirability of retention load is for Enamic cemented with Multilink hybrid with primer/etch, although no statistically significant difference between the values for Enamic and e.max with Multilink hybrid cement primer/etch. MicroRNA Differential Expression of External Cervical Root Resorption Compare to Normal Gingival Tissue in Human Background: External Cervical Root Resorption (ECRR) presents challenges for endodontists regarding both diagnosis and treatment. Molecular pathogenesis of ECRR is still largely unknown or is poorly understood. MicroRNAs (miRNA) control many cell functions especially in the context of cancer and inflammation. Objectives: This proposal seeks to detect miRNA expression patterns in tissues found in ECRR lesions in humans compared to adjacent gingival tissue. Characterizing and identifying altered miRNAs regulation compared to controls can provide a better understanding of the underlying molecular changes during the ECRR process and reveal possible therapeutic targets. Material and methods: MiRNA from non-restorable teeth with ECRR referred for extraction will be collected and a miRNA-array will help to screen for more than 1,000 known human miRNAs. In addition, PCR confirmation for all differentially expressed miRNAs will follow. Conclusion: Once miRNAs are confirmed, a bioinformatics analysis of the possible targeted proteins and molecular pathways will help to elucidate possible pathogenicity of the disease. Cytotoxic Effect of Chitosan Nanoparticles on Normal Human Dental Pulp Cells Introduction: The chitosan nanoparticles have caught much attention recently as they possess an inherent antibacterial property. Many studies have shown that these nanoparticles can improve the antibacterial activity of several dental materials. This study aims to assess its biocompatibility on the normal human dental pulp cells. Methods: Normal human dental pulp cells were cultured with chitosan nanoparticles in concentrations 0.5 mg/mL, 1 mg/mL, 2 mg/mL, 4 mg/mL, and without the chitosan nanoparticles as a control for 7 and 14 days. The size of the nanoparticles was confirmed by the Dynamic Light Scattering and Transmission Electron Microscope to be below 200 nm. On each predetermined point of time, the proliferation and the viability of cells were assessed separately by two different methods. The crystal violet staining was used to measure the cell proliferation while the viability of cells was assessed by evaluating the activity of the mitochondrial dehydrogenase enzyme. Results: At day 7, groups of 2 mg/mL and 4 mg/mL significantly reduced the cell proliferation and cell viability compared to other groups (P < 0.05). The cell proliferation and cell viability were decreased significantly with all nanoparticles concentrations by the end of day 14 in comparison with the control (P < 0.05). Conclusion: Chitosan nanoparticles exhibit a cytotoxic effect on the normal human dental pulp cells. Comparison of CAD/CAM Screw Retained Implant Crowns Sealed by Composite and Enamic Inlay Objective: The aim of this in vitro study is to compare the effect of cyclic loading fatigue on failure load of CAD/CAM screw-retained implant crowns sealed by composite and Enamic inlay. Materials and Methods: Ivoclar e.max and Vita Enamic CAD/CAM screw-retained implant molar crowns (n=44 for each material) and Enamic inlays (n=44) were designed using Sirona in-Lab software system (SW4 4.2.5), and milled using CEREC in-Lab MC XL. All the prepared e.max and Enamic crowns were cemented to Sirona TiBase (B O 4.1 L) using Ivoclar hybrid multilink cement. The access holes were sealed either by using composite or and Enamic inlay (n=22 for each group). After cementation, twelve specimens from each group were subjected to a static load to failure test in a universal mechanical testing machine (Instron 5566A). The mean failure load for each group was calculated. The other 10 specimens for each group were subjected to cyclic loading fatigue under 40% of static failure load for 100,000 cycles. After cyclic loading, the surviving specimens were tested for static failure load. The comparison of failure load between tested groups was analyzed by one-way ANOVA using JMP Pro 13 with α=0.05. Results: Failure load values among the groups showed significant difference. Highest failure load was found in fatigued e.max crowns sealed by Enamic Inlay (3273.98 346.84 N), whereas lowest failure load for Fatigued Enamic crowns sealed by Enamic inlay (2038.94 360.71 N). Failure load of e.max and Enamic crowns did not show any statistical significance difference between static and fatigue paired groups. However, there was statistical significance different failure load between Enamic crowns sealed by Enamic inlay and e.max crowns sealed by either composite or Enamic inlay. Conclusion: The failure load of e.max and Enamic crowns sealed by composite resin was not significantly different. e.max crowns sealed by composite and Enamic inlay showed comparable results. Using Enamic inlay to seal CAD/ CAM screw-retained implant crowns is a feasible new approach. Dental Care Utilization Among US Elderly with Chronic Medical Conditions Objective: To investigate whether comorbidity of systemic health conditions is a barrier to dental care utilization among the elderly. Methods: Data on dental care status and systemic diseases from the National Health and Nutrition Examination Survey (NHANES 2013–2014) for 1004 elderly subjects (>65 years) were analyzed. The main outcome was utilization of dental care, defined as having a dental examination within the past year. The main predictor variables were the presence and number of multiple diseases including hypertension, diabetes, hepatitis, asthma, arthritis, congestive heart failure, coronary heart disease, chronic obstructive pulmonary disorder, cancer, and osteoporosis. Confounding factors included in the analysis were race, age (65–75 or ≥75 years), sex, income (<$45,000, $45,000–$74,999, ≥ $75,000), and education (less than high school, high school diploma, associate or college degree). Chi-square test and multiple logistic regression analysis were conducted using SAS (version 9.4). SAS Survey Procedures with sampling weights were used to estimate correct variance accounting for the complex sampling of the NHANES study. Results: 91.2% had at least one comorbidity; the most prevalent was hypertension (73.4%). Patients with chronic obstructive pulmonary disorder (COPD) were significantly less likely to have utilized dental care in the past year (OR 0.42; 95% CI 0.19–0.93). Patients with three or more and four or more comorbidities (20.57% and 7,46% of the participants, respectively), but not those with two or fewer, were significantly less likely to have utilized dental care after controlling for all confounding factors (OR 0.56, 95% CI 0.35–0.89 and OR 0.38, 95% CI 0.20-0.74). Conclusion: Elderly people with COPD or with three or more systemic diseases are more likely to underutilize dental care. Future programs and/or policy to increase dental care utilization among the elderly should consider interventions that focus on those burdened by several systemic diseases. Racial/Ethnic Disparities in Opioids Prescription by Dentists Objectives: To examine the patterns of opioid and non-opioid analgesics prescription among dental professionals and explore potential racial/ethnic disparities in analgesics prescriptions by US dentists. Methods: Data from Medical Expenditure Panel Survey (MEPS) were analyzed for the year 2014. We included all dental visits during that year associated with an analgesics prescription by dentists. Prescribed analgesics were identified using Multum lexicon drug classification. Chi-square test was used to assess differences between opioid and non-opioid analgesic groups by race/ethnicity, age, gender, income, and dental specialty. Logistic regression models were constructed to measure the association between patients’ race and dentists’ analgesic prescription controlling for age, gender, income, and dental specialty. The person-weight for all the variables were appropriately adjusted to account for the sampling design complexity. Results: In 2014, 62.6% of individuals had at least one dental visit, of those 2.9% received analgesics, and 76.6% of these prescriptions were opioids. In contrast, 56% of analgesics prescribed by health professionals were opioids. Dentists prescribed 4.4% of total opioids prescriptions in that year. Dental specialists were more likely to prescribe opioids than general dental practitioners (p=0.04). Of those who received opioids, 72% were Whites, 11% were Blacks, 8% were Hispanics and 2% were Asians; whereas those who received non-opioid analgesics were 50% Whites, 17% Blacks, 22% Hispanics, and 6% Asians (p<0.001). Age, gender, and income were not significantly associated with opioid/non-opioid prescription. After adjusting for confounders, Hispanics, Blacks and Asians were significantly less likely to receive opioids compared to Whites (OR= 0.27, 0.50, 0.33 respectively, p-value<0.05). Conclusions: The results suggest that there is a potential racial/ethnic disparity in opioid/non-opioid analgesics prescription by dentists in the U.S. However, it is unclear whether this disparity is attributed to overtreatment among white patients or under treatment of other racial minorities. Further research is needed to better understand the causes behind it. Bone Microenvironment-Mediated Cancer Cell Dormancy, Dissemination, and Drug Resistance Introduction: Bone provides an exceptional microenvironment that represents an oasis for cancer cell colonization and drug therapy resistance of which many facets are to date not well understood due to the lack of an ideal model system. Most solid tumors such as breast have a high propensity to colonize bone and once established, results in a terminal and incurable disease. The biological reasons for drug resistance, failure of treatment and reoccurrence are presently unclear. We have utilized our novel ex-vivo cancer-bone metastasis model systems involving co-cultures of free floating mouse calvarial bones with cancer cells and clinically used therapeutic agents to illuminate the above clinical observations. Materials and Methods: A 20-days experiment was designed for MDA-MB-231 and MDA-BO cells in roller tube system under resorption and formation models in the presence and absence of clinically used bisphosphonate, zolendronic acid (ZOL). The groups contained three subgroups; controls with calvaria alone, calvarial bone co-cultured with tumor cells, and calvaria with tumor cells treated with four repeat doses of 2 µM (1µg/2 ml DMEM media) of ZOL (total cumulative 4 µg). The formation groups were supplemented with 150 µg/ml ascorbic acid. Cell count was performed on trypsinized calvaria at 2, 8, and 14 days. Media was changed every 2 days and the changed media was re-seeded in a 24-well for 20 days. To test the impact of chemotherapy agents on cancer-bone metastasis another experiment was set to test effect of 10 µM of Docetaxol on MDA and BO cancer cells under formation and resorption conditions using the above design. Cell count was performed on trypsinized calvaria with cancer colony at 8 days. Results: Tumor burden: Counts from trypsinized calvaria with tumor colony showed no statistically significant difference in the tumor burden between ZOL treated and untreated groups in the resorption condition from day 2 through day 14 in both MDA and BO cells. Under Formation condition, MDA showed no significant difference up to 8 days. However, the difference was significant at days 14 with ZOL treated group having less burden. For BO cells, the tumor burden was not statistically significant different between treated and untreated groups. Comparing the treated and untreated groups with clinically used chemotherapy agent Docetaxol revealed that only ~30% of the cells were affected by chemotherapy in the bone formation model, while ~70% was affected in the resorption model with both cell types. Dissemination model: Counts from the re-seeded media of the 3rd change through the 7th change revealed that the dissemination rate for MDA and BO cells under formation condition is significantly less than for resorption condition. Fluorescent microscopy: MDA and BO tumor-calvaria were treated with Ki 67 antibody showed that under bone resorption condition cancer-bone cell colony were predominantly in proliferation stage. In contrast under bone formation conditions cancer cells were predominantly in dormancy where the cells are stretched out. Conclusions: 1- Both MDA and BO cancer cells showed resistance to bisphosphonate (ZOL) treatment under formation and resorption conditions. 2- Drug resistance of MDA and BO to chemotherapy (Docetaxol) was more evident under formation condition, where cells are in dormancy and not proliferating. 3- The rate of cancer cell dissemination from the bone colony is significantly higher in resorption condition, indicating that cancer cells are dormant under bone formation condition and tend to disseminate less.