No description available.

WORKING HYPOTHESIS: Binding of albumin to various bone graft materials is correlated with the surface porosity of these materials, and therefore the binding of albumin to xenograft is stronger than its binding to synthetic bone graft. NULL HYPOTHESIS: There is no significant difference in the binding strength of albumin to xenograft than its binding to synthetic bone graft materials. Objectives: The increased availability of commercially produced bone graft materials versus autogenous bone makes these materials a desirable product in guided bone and tissue regeneration procedures. The use of commercially produced bone graft materials also provides the opportunity of the addition of certain biologic materials in order to enhance the healing response and to overcome the predominantly inactive nature of most graft materials on the market. The development of an adequate carrier of biologic agents is a crucial step in the creation of a bioactive graft material. This study uses an easily manipulated model protein to study specific characteristics of protein binding and release on two different bone graft substrates commonly used as calcified scaffolds in guided bone and tissue regeneration. This experiment was completed as a first phase in the establishment of a protocol for the future investigation of other relevant proteins that may be important in bone and tissue regeneration. Methods: Bovine serum albumin (BSA) dissolved in physiologic buffered saline solution was poured over 100 mg of either xenograft or synthetic particulate grafting material, and incubated for 24 hrs. at 4°C. The quantity of BSA protein adsorption to the grafting material surface was determined by removing all liquid from the wells after the 24 hr. incubation period, followed by quantification of protein concentrations using the bicinchoninic acid (BCA) protein assay reagent kit. In order to analyze the kinetics of protein release, 1 ml of phosphate-buffered saline (PBS) wash was added to all wells, stirred and removed from each well. This was followed by the addition of 1 ml PBS to all wells and removal of 1 ml of liquid at intervals of 1, 3, and 7 days. Protein concentrations were quantified using the BCA protein assay, and the results were analyzed using a two-way ANOVA. Scanning electron microscopy was performed on samples of xenograft and synthetic graft particles prior to BSA exposure, as well as at days 1 and 7 following the initial 24 hr. incubation and the subsequent PBS wash. Energy-dispersive X-ray spectroscopy was also used to analyze the elemental components of the xenograft and synthetic graft material after BSA treatment. Results: Scanning electron microscopy revealed a more porous surface texture and collagenous appearance of the xenograft graft material, versus the synthetic graft. The energy-dispersive X-ray spectroscopy showed a noteworthy difference between the elemental composition of the xenograft and synthetic graft material. A lower concentration of protein was shown in solution after the initial 24 hr. incubation period in the xenograft samples possibly indicating that more protein was bound to the xenograft particles than the synthetic bone. The remaining solution from the xenograft samples throughout the kinetics of release analysis showed more albumin protein released over time as compared to the synthetic graft samples. Conclusions: This study revealed that xenograft material showed a more porous surface structure and greater binding affinity for bovine serum albumin as compared to the synthetic material. The protocol described in this study is a useful model system for future studies to investigate other proteins involved in wound healing, bone remodeling, and angiogenesis. Protein binding and kinetics of release should be explored on alternative mineralized scaffolds or carrier systems in order to determine an adequate delivery mechanism that allows for sustained release during the optimum time frame for modulation of the healing process. Future experiments should focus on identification of an ideal transport medium for bioactive agents that will direct cells into the osteogenic process to restore new bone and periodontal supporting tissues. The engineering of a material that has the quality of extended release of proteins necessary for the healing cascade has the potential to unlock the key to periodontal regeneration. / Oral Biology

According to a report by the American Society of Interior Designers (1998), there are three primary components of productivity: employee satisfaction, customer satisfaction and financial performance. Factors that affect productivity are many in a small business, such as an orthodontic office. One such factor is the office design. The objective of this study was to qualitatively assess the impact factor of office design on employee satisfaction, customer (or patient) satisfaction, and financial performance. Two types of interviews and one survey were used in this study. The first interview was with the orthodontist(s) and the second was with staff of the orthodontic practices. The survey was for patients and/or parents of patients. Out of the 270 orthodontists practicing in a 50-mile radius surrounding Philadelphia who were contacted by mail, 35 orthodontists agreed to participate, for a response rate of 13%. Give the limitations of the study, the first twenty orthodontists to respond and coordinate an office visit were identified as the sample for this study. A total of 66 staff members were interviewed throughout the 20 office visits. Each participating office was given 50 letters to pass out to patients informing them of the online survey. Of the 1000 letters left at offices, only 42 patients participated in the online survey, for a response rate of 4.2% Based on the results collected from this study, the following conclusions were drawn: 1. Age of the office does not correlate with efficiency or practice volume. 2. Staff members used more positive adjectives to describe newer offices and staff enthusiasm was greatest at newer offices. 3. A lack of space and issues with colliding bodies and crowding were the most common problems with orthodontic office design, reported by staff and doctors alike. 4. Staff members most often spend 15 minutes for an average adjustment appointment. The office layout or design does not seem to be a factor in appointment length. 5. Female doctors more often had offices that reflected their personal preferences. 6. Most doctors believe that their office layout contributes most to efficiency within their office. 7. Trends in orthodontic office design include: an open treatment bay, a stand-up consult area, and a multipurpose room. Additionally, most offices are embracing technology and placing sterilization within their treatment area. / Oral Biology

Objectives: Historically, maxillary posterior teeth have demonstrated a high incidence of periodontal bone loss and consequently tooth loss. The result is often a loss of vertical height in the posterior maxilla due to sinus pneumatization. This study was carried out to evaluate the incidence and clinical implications of maxillary sinus septa to sinus augmentation procedures. Methods & Materials: A total of 100 patient CBCT scans were examined, of whom 50 were male and 50 females. Patients in this study were either edentulous or partially edentulous and were referred to the Misch International Implant institute (MIII) specifically for possible sinus surgery related to future implant placement. For the purposes of this study, a minimum height of 3mm was used to classify bony lamellae as septa. Results: We found a total of 37 septa in 200 sinuses (18.5%). This corresponds to 29% of the subjects. We can break down the results based on sex, finding the incidence of 30% in females and 28% in males. The majority of the subjects with septa were in the 60+ age bracket. Additionally, all of the septa in our study were oriented in a bucco-palatal direction Conclusions: Detailed information about the sinus anatomy / pathology and specifically the presence of septa (their location and morphology) with the aid of CT scan analysis may provide crucial information to reduce unnecessary complications associated with maxillary sinus surgery i.e. sinus floor elevation. / Oral Biology

Dark-pigmented, gram-negative, anaerobic rods are often recovered in large numbers from the subgingival microbiome of human periodontitis, and are statistically associated with progression of chronic periodontitis. Due to their frequent expression of beta-lactamase enzymes, which hydrolyze and degrade beta-lactam class antibiotics, these species may compromise systemic periodontal antimicrobial chemotherapy involving amoxicillin, which may lead to clinical therapeutic failures in chronic periodontitis therapy. Recent studies using phenotypic methods have identified the in vitro growth of Prevotella intermedia/nigrescens in the presence of therapeutic threshold concentrations of amoxicillin, which is indicative of species antibiotic resistance. Because of uncertainties with their taxonomic classification, only limited information is available on the distribution of amoxicillin-resistant species within the group of dark-pigmented, gram-negative, anaerobic rods that may colonize and inhabit human subgingival sites. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and its associated analytic software, was recently approved for clinical microbiology diagnostic use in the United States by the United States Food and Drug Administration. This methodology is capable of definitively identifying 4,613 different oral and non-oral microbial species based on mass spectra of their bacterial protein profiles, including many dark-pigmented, gram-negative, anaerobic rods of subgingival origin. However, MALDI-TOF mass spectrometry has yet to be used for species iii identification of dark-pigmented, gram-negative, anaerobic rods recovered from chronic periodontitis lesions, and resistant in vitro to amoxicillin. As a result, the purpose of this study was to use MALDI-TOF mass spectrometry to identify to a species-level the patient distribution of dark-pigmented, gram-negative, anaerobic rods isolated from the subgingival microbiota of chronic periodontitis patients and exhibiting in vitro resistance to therapeutic concentrations of amoxicillin. Methods: 24 chronic periodontitis patients contributed 71 fresh subgingival cultivable isolates (one to 11 isolates per patient) which were presumptively identified by their brown to black colony pigmentation on anaerobically-incubated enriched Brucella blood agar primary isolation plates containing amoxicillin at 8 μg/ml as amoxicillinresistant, dark-pigmented, gram-negative, anaerobic rods. Each of the amoxicillinresistant, dark-pigmented clinical isolates were subjected to MALDI-TOF mass spectrometry analysis using a bench top mass spectrometer, Bruker FlexControl 3.0 software, and MALDI Biotyper 3.1 software (Bruker Daltonics, Billerica, MA, USA), which contains mass spectra for dark-pigmented, gram-negative, anaerobic rods in its reference library of bacterial protein profiles. A MALDI Biotyper log score of ≥ 1.7 was required for reliable taxonomic classification of the clinical isolates. Results: Only 4 (16.7%) of the chronic periodontitis patients yielded two different dark-pigmented species on amoxicillin-supplemented primary isolation plates, while all other study patients had only one amoxicillin-resistant, dark-pigmented species. Amoxicillin-resistant strains of Prevotella nigrescens were identified in 11 (45.8%) patients, Prevotella intermedia in 8 (33.3%) patients, Prevotella denticola and/or Prevotella species in 3 (12.5%) patients, Porphyromonas gingivalis in 2 (8.3%) patients, and Prevotella melaninogenica in one (4.2%) patient. 50 (70.4%) of the amoxicillinresistant clinical isolates exhibited MALDI Biotyper log scores of ≥ 1.7, the threshold for reliable taxonomic classification, whereas 21 (29.6%) had log scores < 1.7, indicating a less reliable species identification. Conclusions: These findings demonstrate that a range of specific amoxicillinresistant bacterial species comprise cultivable isolates of dark-pigmented, gram-negative, anaerobic rods in the human chronic periodontitis subgingival microbiota. P. nigrescens was the most frequently isolated amoxicillin-resistant, dark-pigmented subgingival bacterial species, followed by P. intermedia. Two study patients surprisingly revealed amoxicillin-resistant strains of P. gingivalis. The occurrence of amoxicillin-resistant, dark-pigmented rods in chronic periodontitis lesions may complicate selection, and markedly reduce the potential effectiveness, of systemic periodontal antimicrobial therapies involving beta-lactam antibiotics. / Oral Biology

No description available.

OBJECTIVE: Logical function of Lipopolysaccharide (LPS)-Induced Factor (LIF), and to identify the factors involved in the LIF signaling pathway in response to LPS, using a new method (Hybrid) for protein detection. The hybrid method combines the main features of the ELISA and Western blot assay and provides the advantage of measuring multiple proteins simultaneously. MATERIALS & METHODS: A culture of mouse RAW c cells in RPMI media supplemented with 10% FBS at 37°C in 5% CO2 was established. Polymerase Chain reaction (PCR) used specifically designed primers and DNA cloning of LIF. Cloned LIF cDNA was transfected into macrophages. Western blot, ELISA, and hybrid method analyses were used to determine production of proinflammatory cytokines. RESULTS: LIF induced TNF-ɑ production during the initial time interval (1-12 hrs) and reduced TNF- ɑ production during the later time interval (10-24 hrs). LIF induces apoptotic proteins such as Caspase 1/3 at that time. The CASPASE 1/3 gene expression steadily increased. The 7% Formaldehyde solution was suitable for concentration for cell lysate fixation, and was used in a 96-well microplate with more stringent washing conditions (shaking at 100-150 rpm), which can specifically detect an antibody without a false positive. A cell lysate concentration of 2 μg assured protein detection by the hybrid method. At least 20 minutes were needed for protein detection but 40 minutes was the optimal time. CONCLUSION: There was a two-sided association between LIF and TNF-ɑ: LIF activates TNF-ɑ gene expression in early stages and suppresses its production in later stages by inducing the apoptotic protein, CASPASE 1/3. The hybrid method is suitable for protein detection in various types of cells. Usage of the hybrid method allows detection and normaliz intracellular and extracellular proteins. Factors such as P38, ERK1, and MCP-1 are involved in the LIF-dependent signaling pathway.

Introduction: One of the main causes of endodontic treatment failures is the persistence of microorganisms within the root canal systems. Piezoelectric materials, including barium titanate (BaTiO3), offer antibacterial effects. The aim of this project is to develop an endodontic sealer embedded with piezoelectric fillers for the prevention of root canal infections. Materials and methods: BaTiO3 particles were mixed with EndoSequence (BC) sealer in two concentrations (5% and 10%wt). Flowability test was conducted for each type of sealer according to ISO-6876 guidelines. The antibacterial evaluation was performed using an ex-vivo model. Single-rooted extracted teeth were instrumented, and canals were infected with Enterococcus faecalis for 7 days. Following the root canal treatment, the sealers (BC, BC+ BaTiO3-5%, BC+ BaTiO3-10%) were used for obturation. Untreated teeth were used as positive control. Specimens with BaTiO3 particles were subjected to compression cyclic loading to activate the piezoelectric charges and resemble mastication forces. Cell viability (CFU/mL) was used to determine the number of bacteria at the bonded interface of the sealant. ANOVA was used to evaluate the statistical differences among the groups. Results: The addition of BaTiO3 particles into BC Sealer resulted in a decrease in flowability (BC: 21.7 ± 0.55 mm, BC+ BaTiO3-5%:19.5 ± 0.50 mm, BC+ BaTiO3-10%:17.44 ± 0.40 mm). All sealers exhibited antibacterial properties. The addition of BaTiO3 nanoparticles significantly enhanced the antibacterial efficacy compared to BC sealer. However, there was no significant difference between the BC+BTO 5% and BC+BTO 10% groups (BC: 3.90 ± 0.27, while both the BC+BTO 5%: 3.31 ± 0.12, BC+BTO 10%: 3.01 ± 0.22). Conclusion: An antibacterial piezoelectric endodontic sealer was developed. Adding more than 5%w of BaTiO3 particles into BC sealers enhanced the antimicrobial efficacy. However, adding more than 10% of BaTiO3 negatively affects the sealer's flow properties. / Oral Biology

published_or_final_version / Endodontics / Master / Master of Dental Surgery

Thesis (M. Sc.)--Lakehead University, 1995. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.