Browsing by Author "Kowolik, Michael J."
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Item Assessment of Orthodontic Treatment Results: Two-Phase Treatment (Early Intervention) vs. One-Phase Treatment (Late Intervention)(2003) Hsieh, Tsung-Ju; Roberts, W. Eugene; Baldwin, James J.; Hohlt, William F.; Kowolik, Michael J.; Shanks, James C.There is still a lack of consensus among orthodontists regarding the degree of success of different treatment modalities applied during the early to late mixed dentition stages. The purpose of this study was to compare the treatment outcome of one-phase with two-phase treatment with objective evaluation criteria. The null hypothesis is that there is no difference in the treatment quality between early and late treatment groups, among cases finished in year 1998, 1999 and 2000 or among three Angle's Classes or between extraction and non-extraction cases. Pre-treatment and post-treatment records of all patients treated in the orthodontic clinic at the Indiana University School of Dentistry who had their treatment completed during the three years (1998, 1999, 2000) were evaluated by American Board of Orthodontics (ABO) objective grading system and clinical assessment criteria developed in the IUSD orthodontic section. The results of the study showed that there were 512 cases finished in these 3 years. Among these 512 cases the treatment was most often started at age 12, followed by age 13. Poor occlusal contact and improper third order of molars, longer treatment time, and poor dentition were major contributors that made the treatment quality poor. Early debond tended to occur more often with boys than girls. Generally Angle's Class I cases and the cases finished in year 1998 had better treatment results. Although the early treatment group had longer treatment time than late treatment group, the final treatment quality was comparable with that of the late treatment group.Item Digital Microradiography: In Vitro Validation of a Novel Imaging Technique(2004) Yip, Gary Ka Fai; Roberts, W. Eugene; Everett, Eric; Garetto, Lawrence P.; Hancock, E. Brady; Kowolik, Michael J.; Parks, Edwin T.; Platt, Jeffrey A.; Zunt, Susan L.Microradiography has been widely used in mineralized tissue research in determining the mineral content within the specimens being studied. There are considerable limitations of this ageing gold standard such as unavailability of the high-resolution spectroscopic plates and prolonged imaging and processing times. The present study aimed at developing and validating a novel digital microradiographic technique that is not restricted by the limitations of conventional microradiography. Reproducibility of digital microradiography was investigated by studying 4 repeated images of 10 randomly selected sectioned implant-bone specimens acquired by 2 examiners over 2 weeks. The acquired images were analyzed by both manual and automated digital subtractions. Correlation between digital and conventional microradiography was performed by digital subtraction of 23 matching images acquired by both microradiographic techniques. A comparison between manual and automated digital subtraction enabled evaluation of the influence of the digital subtraction protocols on the results of the subtraction. A direct digital microradiographic technique has been developed which does not require analogue recording medium and film processing. The robustness of the digital microradiography was evidenced by the narrow range of means and standard deviations for intra- and inter-examiner reproducibility. The intra-examiner means and standard deviations ranged from 126.54-128.42 and 4.11-5.34 respectively. The inter-examiner means and standard deviations ranged from 126.71-129.87 and 4.68-5.70 respectively. The detection threshold for the digital microradiography was 5 gray scales or 3.9 percent, which was comparable to digital radiography. The high concordance between conventional and digital microradiography was demonstrated by the mean and standard deviation of 8.69 and 1.75 gray scales respectively. There was a statistically significant difference between the results obtained by manual and automated digital subtraction, but the clinical significance is yet to be determined.Item The effect of cigarette smoking on the virulence of streptococcus mutans caries and cardiovascular diseases-epidemiological analysis and in vitro studies(2010) Zheng, Cunge; Gregory, Richard L.; Windsor, L. Jack; Kowolik, Michael J.; Steele, Gregory K.; Holt, Robert G.The impact of tobacco smoking on human health is well documented. The influence of smoking on tooth loss and cardiovascular diseases was investigated in the current study via both epidemiology and in vitro studies. From analyzing the 2006 Behavioral Risk Factor Surveillance System (2006 BRFSS) database, we confirmed that smoking was significantly associated with the number of teeth lost in a dose-dependent manner and smoking cessation reduced the risk when compared to those subjects continuing to smoke. In addition, the virulence factors related to caries were compared between Streptococcus mutans and Streptococcus gordonii in response to cigarette smoking condensate (CSC) treatment. We observed that S. gordonii was more susceptible to CSC treatment than S. mutans. CSC significantly enhanced S. mutans sucrose-dependent and independent adherence. Western blot assays revealed that several bacterial surface proteins including glucosyltransferase (GTF), glucan-binding proteins and antigen I/II, were significantly upregulated for the treated S. mutans. These findings suggested that the oral environment with CSC may favor a cariogenic dominant composition, which may increase the risk for smokers to develop caries. We also found that smoking and oral health status modified each other and synergistically increased the risk of CVD and this joint effect was more pronounced among the youngest age group using the 2006 BRFSS database. To further understand the joint effect, we conducted an in vitro study to investigate bacterial attachment to fibronectin and endothelial cells in response to smoking condensate treatment. Our study clearly demonstrated CSC significantly enhanced S. mutans attachment to both soluble and immobilized fibronectin as well as endothelial cells. Furthermore, our data suggested that bacteria possessed several adhesins that bound to host tissues and endothelial cells also had multiple receptors for bacterial attachment. Among these adhesins, antigen I/II seemed essential for bacterial attachment to endothelial cells without CSC. The knowledge of bacterial attachment to host tissues in the presence of CSC may help in developing different preventive or therapeutic strategies against attachment and colonization of the host by S. mutans.Item Effect of HA-coating and HF etching on experemental zirconia implant evaluation using in vivo rabbit model(2010) Huang, Sung-En; Chu, Tien-Min Gabriel; John, Vanchit (Vanchit Kurien), 1965-; Kowolik, Michael J.; Zunt, Susan L., 1951-; Blanchard, Steven B.The objective of this study was to evaluate the in vivo performance of the hydroxyapatite (HA) coating and hydrofluoric acid (HF) etching zirconia (ZrO) implants and to compare the result with titanium (Ti) implants treated in a similar manner. A total of four different implant types were tested in this study. Threaded zirconia implants with HA coating (Test 1) and zirconia implants with HF-treated surfaces (Test 2) were used to compare to the same size of titanium implants treated in identical fashion (control 1 and control 2). All implants measured about 3.5 mm at the thread diameter and 7.0 mm in total length. Each rabbit received two zirconia and two titanium implants treated in the same manner (either HA-coated or HF-etched). The samples were implanted into the rabbit tibias and retrieved at 6 weeks. Upon retrieval, 24 specimens (6 samples for each group) were fixed and dehydrated. The samples were then embedded undecalcified in PMMA for histomorphometry to quantify the bone-to-implant contact (BIC). Another 24 samples were kept in 0.9% saline and were evaluated using removal torque (RT) analysis to assess the strength of the implant-to-bone interface. The histomorphometric examination demonstrated direct bone-to-implant contact for all four groups. HA particle separation from the implants surface was seen in a majority of the HA-coated samples. No signs of inflammation or foreign body reaction were found during examination. Due to the HA particle smear contamination in the ZrO-HA group, no data was collected in this group. The mean BIC at the first three threads of the Ti-HA, Ti-HF and ZrO-HF were 57.78±18.22%, 46.41±14.55% and 47.41±14.05%, respectively. No statistically significant difference was found pair-wise among these three groups. When comparing the BIC data with the machined-surface implants, a statistically significant difference was found between the Ti-HA versus Ti implant group and the Ti-HF versus Ti implant group. The mean bone area (BA) at the first three threads for Ti-HA, Ti-HF and ZrO-HF showed statistically significant difference (p<0.05) between the ZrO-HF and Ti-HA groups, favoring the ZrO-HF group. The value of the peak removal force could only be collected from the Ti-HA group during the removal torque test. The mean RT value for the Ti-HA group was 24.39±2.58 Ncm. When comparing the RT result with our pilot study using machined-surface implants, the Ti-HA group showed statistically significant (p<0.05) higher values than the machined-surface Ti implants. The result of this study proves the in vivo biocompatibility of all four implant types tested. In the three measurable implant groups, the histomorphologic analysis showed comparable osseointegration properties in this animal model.Item The Effects of Nicotine on the Proteolytic Activity of Periodontal Pathogens(2011) Kaeley, Janice,1976-; Gregory, Richard L.; Blanchard, Steven B.; Kowolik, Michael J.; Windsor, L. Jack; Zunt, Susan L., 1951-Periodontal disease is the leading cause of tooth loss in adults. Bacterial biofilm on tooth surfaces is the primary initiator of periodontal disease. Various factors contribute to the severity of periodontal disease including the different virulence factors of the bacteria within the biofilm. In the progression of periodontal disease, the microflora evolves from a predominantly Gram positive microbial population to a mainly Gram negative population. Specific gram negative bacteria with pronounced virulence factors have been implicated in the etiology and pathogenesis of periodontal disease, namely Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola which form the red complex of bacteria. The orange complex bacteria become more dominant in the maturation process of dental plaque and act to bridge the early colonizers of plaque with the later more dominant red complex bacterial and consists of such bacteria as Campylobacter showae, Campylobacter rectus, Fusobacterium nucleatum and Prevotella intermedia. Perhaps the most investigated contributing factor is the relationship between smoking and periodontal disease. When examining the association between cigarette smoking and interproximal bone loss, greater bone loss is associated with higher cigarette consumption, longer duration (i.e., pack year history) and higher lifetime exposure. The presence of various virulence factors such as the production of a capsular material, as well as the proteolytic activity of the various periopathodontic bacteria has been associated with the pathogenesis of periodontitis. Even though many different enzymes are produced in large quantities by these periodontal bacteria, trypsin-like enzymes, chymotrypsin-like enzymes and elastase-like enzymes, as well as dipeptidyl peptidase-like enzymes, have been thought to increase the destructive potential of the bacterium and mediate destruction of the periodontal apparatus. More specifically, it is hypothesized that the proteolytic activity of other clinically important periodontal pathogens, such as Fusobacterium nucleatum, Prevotella intermedia and Porphyromonas assacharolyticus, is increased in the presence of nicotine. The purpose of this study was to determine the effects of nicotine on F. nucleatum, P. intermedia and P. assacharolyticus proteolytic activity. Cultures were maintained on anaerobic blood agar plates containing 3% sheep blood. Bacterial cells were harvested from the plates and washed. Washed F. nucleatum, P. intermedia and P. assacharolyticus cells were incubated with 1 mg/ml of nicotine. Bacterial cells not incubated with nicotine were used as positive controls. Secreted enzymatic activity was measured using the synthetic chromogenic substrates glycyl-L-proline-p-nitroanilide (GPPNA), N-succinyl-L-alanyl-L-alanyl-L-alanyl-p-nitroanilide (SAAAPNA), N-succinyl-alanine-alanine-proline-phenylalanine-p-nitroanilide (SAAPPPNA) and N-α-benzoyl-L-arginine-p-nitroanilide (L-BAPNA) (Sigma-Aldrich Products, St. Louis, MO, USA). Appropriate means and standard deviations were determined for each of the enzymatic activities measured and analysis of variance (ANOVA) was used to compare the groups utilizing a 5% significance level for all comparisons. Results demonstrated that after 60 minutes of incubation of F. nucleatum, P. intermedia and P. assacharolyticus cells with 1 mg/ml of nicotine and the various synthetic substrates, had the following proteolytic activity for GPPNA: 0.83 ± 0.14, 0.72 ± 0.03 and 0.67 ± 0.10, respectively; SAAAPNA: 0.82 ± 0.06, 0.76 ± 0.05 and 0.68 ± 0.08, respectively; SAAPPPNA: 0.90 ± 0.13, 0.85 ± 0.17 and 0.72 ± 0.03, respectively; and BAPNA: 0.81 ± 0.15, 0.74 ± 0.13 and 0.74 ± 0.16, respectively. In conclusion, the results indicate that in the presence of 1 mg/ml of nicotine, the proteolytic activity of F. nucleatum and P. assacharolyticus was increased with all of the synthetic substrates (with statistical significance seen only in the increases with F. nucleatum and GPPNA, SAAAPNA and BAPNA). The proteolytic activity exhibited an increasing trend in activity for P. intermedia with SAAPPPNA and BAPNA but a decreasing trend in activity with GPPNA and SAAAPNA when incubated with 1 mg/ml of nicotine, once again demonstrating no statistical significance for any of the substrates. Therefore, it could be concluded that based on these results nicotine at a concentration of 1 mg/ml may increase the proteolytic activity of periodontal pathogens and thus may increase periodontal disease activity and subsequent periodontal breakdown. Further studies are needed to validate these results utilizing different concentrations of nicotine.Item Effects of tobacco on human gingival fibroblasts(2011) Zhang, Weiping; Windsor, L. Jack; Song, Fengyu; Kowolik, Michael J.; Lee, Chao-Hung; Subramaniam, Denise RogersThe negative heath consequences of smoking are widely recognized, but there are still about 20% of the people in United States using tobacco products. Cigarette smoke condensate (CSC), the particulate matter of cigarette smoke, is comprised of thousands of chemicals (e.g., nicotine). Secondary only to bacterial plaque, cigarette smoking is a major risk factor for periodontal disease. Human gingival fibroblasts (HGFs) are the main cellular component of periodontal connective tissues. During the development of periodontal disease, collagen degradation occurs. Collagen is the major extracellular matrix component of the gingiva. The major extracellular matrix degrading enzymes produced by the HGFs are the matrix metalloproteinases (MMPs). The MMPs are mainly modulated by the tissue inhibitors of metalloproteinases (TIMPs). In this dissertation, three studies aimed at understanding the effects of tobacco on human gingival fibroblasts and their mechanisms have been conducted: the effects of CSC on HGF-mediated collagen degradation; comparison of the effects of CSC on HGFs with that of nicotine; and the combined effects of CSC and bacteria on HGFs. The cell proliferation of HGFs decreased and cytotoxicity increased in HGFs treated with increasing concentrations of CSC. CSC increased the collagen degrading ability of the HGFs by altering the production and localization of MMPs and TIMPs. Nicotine is one of the major components and the most pharmacologically active agent in tobacco. The percentage of nicotine in the CSC was 2.4%. CSC (100 µg/ml) increased the collagen degrading ability of the HGFs by affecting membrane associated MMP-2, MMP-14, and TIMP-2, but the level of nicotine in the CSC may only play a limited role in this process. Porphyromonas gingivalis (P. gingivalis) is an opportunistic pathogen involved in periodontal disease. The combined effects of CSC and P. gingivalis supernatant increased HGF-mediated collagen degradation by destroying the balance between the MMPs and TIMPs at the protein and mRNA levels. This project demonstrated that tobacco (with or without P. gingivalis) increased HGF mediated collagen degradation, as seen in the periodontal disease, through altering the MMPs and TIMPs.Item Empowering Department Chairs to Facilitate Faculty Mentoring(Office of Academic Affairs, IUPUI, 2016-09-16) Kowolik, Michael J.; Edwards, Paul C.This poster describes the progress and lessons learned as a result of newly implemented Faculty Mentoring Program in the Indiana University School of Dentistry (IUSD).Item Investigating the Response of Human Neutrophils to Hydrophilic and Hydrophobic Micro-Rough Titanium Surfaces(MDPI, 2020-08-03) El Kholy, Karim; Buser, Daniel; Wittneben, Julia-Gabriella; Bosshardt, Dieter D.; Van Dyke, Thomas E.; Kowolik, Michael J.; Periodontology, School of DentistryVarious treatments have been used to change both the topography and chemistry of titanium surfaces, aiming to enhance tissue response and reduce healing times of endosseous implants. Most studies to date focused on bone healing around dental implants occurring later during the healing cascade. However, the impact of the initial inflammatory response in the surgical wound site on the success and healing time of dental implants is crucial for implant integration and success, yet it is still poorly understood. The purpose of this study was to investigate the effect of titanium surface hydrophilicity on the response of human neutrophils by monitoring oxygen radical production, which was measured as chemiluminescence activity. Materials and Methods: Neutrophils were isolated from human donors’ blood buffy coats using the double sucrose gradient method. Neutrophils were exposed to both hydrophilic and hydrophobic titanium surfaces with identical topographies in the presence and absence of human serum. This resulted in six experimental groups including two different implant surfaces, with and without exposure to human serum, and two control groups including an active control with cells alone and a passive control with no cells. Two samples from each group were fixed and analyzed by SEM. Comparisons between surface treatments for differences in chemiluminescence values were performed using analysis of variance ANOVA. Results and Conclusion: In the absence of exposure to serum, there was no significant difference noted between the reaction of neutrophils to hydrophilic and hydrophobic surfaces. However, there was a significant reduction in the mean and active chemiluminescence activity of neutrophils to serum-coated hydrophilic titanium surfaces than to serum-coated hydrophobic titanium surfaces. This suggests that surface hydrophilicity promotes enhanced adsorption of serum proteins, which leads to decreased provocation of initial immune cells and reduction of local oxygen radical production during wound healing. This can help explain the faster osseointegration demonstrated by hydrophilic titanium implants.Item Mentoring Academy Proposal (Resubmission): IU School of Dentistry(Office of Academic Affairs, IUPUI, 2015-02-02) Kowolik, Michael J.; Edwards, Paul C.Item The Responses of Human Neutrophils to Tobacco Smoke Components(2012) Al-Shibani, Nouf Khider; Windsor, L. Jack; Song, Fengyu; Kowolik, Michael J.; Goodpaster, John V. (John Vincent); Subramaniam, Danise RogersTobacco smoking is considered a major modifiable risk factor for periodontal disease. Tobacco contains about 6700 compounds and almost 4000 compounds of these have been identified in tobacco smoke. Nicotine is the addictive ingredient in tobacco and has been shown to affect multiple cellular processes. Cigarette smoke condensate (CSC) is the particulate matter of smoke. It is believed to be a powerful inducer of inflammatory responses. Neutrophils are the first line of host defense and are critical cells in the maintenance of periodontal health through their role in the control of bacteria, but they can also contribute to the progression of periodontal disease by the production and release of reactive oxygen species (ROS). Virulence factors from periodontal pathogens, such as Porphyromonas gingivalis (P. gingivalis), stimulate the respiratory burst of neutrophils. In this dissertation, three studies aimed at understanding the oxidative activity of neutrophils when stimulated with either nicotine, cigarette smoke condensate (CSC) or four other components of tobacco smoke (2-naphthylamine, hydroquinone, acrolein, and acetaldehyde) with or without P. gingivalis supernatant. The release of matrix metalloproteinase-9 (MMP-9) was also examined. ROS production increased significantly when the neutrophils were stimulated with nicotine. P. gingivalis induced the maximum ROS production when compared to all the other components examined. The combination of nicotine and P. gingivalis did not have an additive effect on ROS production. Nicotine significantly increased the MMP-9 release from the neutrophils. On the contrary, CSC inhibited ROS production at all the concentrations examined. The combination of CSC and P. gingivalis resulted in the inhibition of ROS production. MMP-9 release was also increased from the CSC-treated neutrophils. The four other tobacco smoke components examined affected ROS production and MMP-9 release differently. These projects demonstrated that CSC inhibited the ROS production from neutrophils, which can be attributed to several components in tobacco smoke that may include acrolein and hydroquinone. More research is needed to determine the mechanisms of inhibition and if other tobacco components are involved in ROS inhibition