Browsing by Author "Zunt, Susan L."
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Item The antibacterial effect of new intracanal medicaments against established mutlispecies biofilm(2017) Troxel, Alex; Spolnik, Kenneth J.; Gregory, Richard; Ehrlich, Ygal; Bringas, Josef; Zunt, Susan L.; Yassen, GhaethWe investigated the antibacterial effect of low concentrations of double antibiotic paste (DAP) loaded into a methylcellulose system against bacterial biofilms obtained from mature and immature teeth with necrotic pulps. Standardized radicular dentin specimens were randomly divided into six experimental groups (n = 20). Group 1: 5mg/mL DAP treatment. Group 2: 1mg/mL DAP treatment. Group 3: Calcium hydroxide (Ca(OH)2) treatment. Group 4: Methylcellulose. Group 5: No treatment. Group 6: No bacteria or treatment. Clinical bacterial isolates were obtained from mature and immature teeth with necrotic pulps indicated for endodontic regeneration or routine endodontic treatment, respectively. Specimens in each group were inoculated with either bacterial isolates (n = 10) and incubated anaerobically for 3 weeks. Specimens were then treated for one week with the assigned group treatment. Treatments were rinsed with sterile saline and biofilms were detached and spiral plated using biofilm disruption assays. Wilcoxon Rank Sum tests followed by pair-wise comparisons were used for statistical analyses. Treatment of infected dentin with 1 mg/ml of DAP, 5 mg/mL of DAP, and Ca(OH)2 demonstrated significant and substantial antibiofilm effects in comparison to untreated control groups or groups treated with placebo paste. Furthermore, 1 mg/mL of DAP caused complete eradication of biofilm obtained from mature tooth with necrotic pulp. However, the same concentration was not able to completely eradicate biofilm obtained from the immature tooth with necrotic pulp. Low concentrations of DAP (1-5 mg/mL) loaded into a biocompatible methylcellulose system demonstrated significant antibacterial effects against biofilm obtained from both mature and immature teeth with necrotic pulps.Item Biomechanical and histological evaluation of a new zirconia implant in a canine model(2015) Hamada, Yusuke; Chu, Tien-Min Gabriel; Prakasam, Sivaraman; Zunt, Susan L.; Liu, Sean Shih-Yao; Blanchard, StevenBackground: Currently titanium implant fixtures are considered as a gold standard because of their biocompatibility and their clinical success rates have been well documented. The esthetic outcome of restorations supported by titanium implants may be compromised if the dark gray color of the implant shows through a thin peri-implant mucosa or if the implant fixture becomes visible following soft tissue recession. Also titanium might cause allergic reactions. For these reasons, zirconia implants have been considered as alternative materials because of their white color, high material properties and biocompatibilities. Still, further investigations are necessary to confirm the in-vivo performance of these implants. Purpose: The purpose of this study is to determine the histomorphometric and biomechanical properties of zirconia implants manufactured by Shofu Inc. with a sand-blasted and acid-etched surface treatment, compared to that of the titanium implants from the same manufacturer with a sand-blasted and acid-etched surface treatment in a canine model. Material and Methods: Six beagle dogs (1-2 years old) will be used in this split mouth trial. After 8 weeks following extraction of the second to fourth mandibular premolars, zirconia implants (experimental group) and titanium implants (control group) were placed on the each side of mandible. At 8 weeks and 12 weeks after implant placement, the animals were sacrificed, and implants were removed in block sections, and histological and histomorphometric analyses were measured. Specifically, the bone-implant contact (BIC), bone area (BA), removal torque (RTQ), mineral apposition rate (MAR), bone forming area (BFA), and Periotest value (PTV) of the two groups were studied and compared. Results: At 12 weeks post operatively, one Shofu thread type Ti implant were not integrated. Over all failure implant was 0/12 in zirconia group, and 1/12 in titanium group. In 8 weeks samples, only statistical differences were higher BA (p=0.02) in macro threads area and BFA (p=0.02) in zirconia implants group than titanium implants group. In 12 weeks group, zirconia implant group showed higher MAR at 9-10 and 10-11weeks time frame (p=0.02, and 0.04 restectively), and PVT value (p=0.01) than titanium implants group. Removal torque value increased in both titanium and zirconia group with time. Average of removal torque value showed higher in titanium implants than zirconia implants, but the differences were not statistically significant in both 8 weeks (Ti; 64.16±16.93 N-cm, ZrO₂: 42.5±6.01 N-cm : p=0.247) and 12 weeks (Ti; 82.5±9.41 N-cm, ZrO₂: 51.3±19.38 N-cm: p=0.16). In the removal torque analysis, it is observed that the bone-implant interface seems to be of more rigid and brittle in nature as indicated by the lower averaged onset angle, peak angle, area under curve and RTQ. Conclusion: Zirconia implants group showed higher value of BA with macro thread and BFA in 8weeks and MAR at 9-10, 10-11 weeks period, and PVT in 12 weeks post operatively. Within the limited number of samples tested in this study, there is no difference between the BIC and RTQ of zirconia and titanium implants after 8 and 12 weeks of implantation.Item Comparison of Electrosurgical and Formocresol Pulpotomy Procedures(1997) Fulkerson, Bradley Todd; Dean, Jeffrey A.; Avery, David R.; Sanders, Brian J.; Zunt, Susan L.; Legan, Joseph E.Formocresol is the most commonly used pharmacologic pulpotomy agent. Concerns over its safety have led investigators to search for new pulpotomy medicaments. This study compared the electrosurgical pulpotomy with the formocresol pulpotomy in teeth requiring pulp therapy after carious involvement. There were 25 pulpotomies performed in each group. The teeth were evaluated for clinical and radiographic success after at least six months. In the electrosurgical group, the clinical and radiographic success rates were 96 percent and 84 percent, respectively. The age range at the time of treatment was 26 to 97 months, with a mean treatment age of 63.6 months. The postoperative observation time range was six to 31 months, with the mean being 10.9 months. In the formocresol group, the clinical and radiographic success rates were 100 percent and 92 percent, respectively. The age range at the time of treatment was 32 to 126 months, with a mean treatment age of 68.2 months. The postoperative observation time ranged from five to 25 months, with the mean being 11.5 months. The electrosurgical and formocresol groups were compared for differences in the percentage of successes by using a Fisher's Exact test. There were no statistical differences between the two groups at the p < 0.05 level. Therefore, this study failed to demonstrate a statistically significant difference in the success rate between the electrosurgical and formocresol pulpotomy techniques and supports the use of the electrosurgical pulpotomy as a viable and safe alternative to formocresol.Item Development of a Double Antibiotic Electrospun scaffold for Root Canal Disinfection(2015) Kutanovski, Christopher D.; Bottino, Marco C.; Spolnik, Kenneth J.; Ehrlich, Ygal; Gregory, Richard L.; Zunt, Susan L.Objective: This study synthesized electrospun polymer-based scaffolds containing ciprofloxacin (CIP) and doxycycline (DOX), as a scaffold mimic of Double Antibiotic Paste (DAP) and determined, in vitro, its mechanical properties, chemical composition, and antimicrobial effectiveness against multiple endodontic bacterium. Methods: Polydioxanone sutures (PDS) were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFP), mixed with CIP/DOX (i.e., 50%), and electrospun under optimized conditions into fibrous scaffolds. Tensile testing was used to evaluate the mechanical properties. Antimicrobial efficacy was determined over time using aliquots collected at 1, 4, 7, 14 day and agar diffusion assays. Two-Way Anova. Significance P < 0.05. Results: Tensile strength (MPa) of the CIP/DOX scaffold did not show significant difference from the control (pure PDS). Elongation at break (%) did show a significant difference between CIP/DOX scaffolds and the control group. Young’s modulus of elasticity (MPa) showed a significant difference between CIP/DOX scaffolds and the control. CIP-containing scaffolds did not inhibit Gram-negative (F. nucleatum and P. gingivalis) bacteria as effectively when compared to Gram-positive bacteria (E. faecalis and S. gordina). DOX-containing scaffolds showed less inhibition against Gram-positive (E. faecalis and S. gordina) bacteria then Gram-negative bacteria (F. nucleatum and P. gingivalis). In combination, CIP/DOX scaffolds showed significant inhibition against G(-) and G(+) bacteria. Conclusion: Electrospun double antibiotic scaffold demonstrated increased antimicrobial efficacy proving the potential for future clinical use to disinfect the RCS in permanent immature necrotic teeth to aid in regenerative treatment and or in persistent infections.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 Effects of DynaMatrix on Angiogenic Cytokine and Matrix Metalloproteinase Expression from Human Endothelial Cells: An In-vitro Study(2015) Hill, Scott Thomas; Spolnik, Kenneth J.; Warner, Ned; Zunt, Susan L.; Windor, L. Jack; Bringas, Josef; Ygal, EhrlichIntroduction: Regenerative endodontics (RE) is a treatment alternative for the infected immature tooth to establish an environment in the canal that enables continued root development and the growth of pulp or pulp-like tissue within the canal. A scaffold created in the canal encourages the formation of vital tissue. The porcine sub-intestinal-submucosa (SIS) membrane, Dynamatrix®, has the potential to serve as an endodontic scaffold. Research at Indiana University School of Dentistry (IUSD) has shown that Dynamatrix® can support the growth of human dental pulp stem cells (HDPSC) and human pulp fibroblasts (HPF). Positive angiogenic cytokine profiles were seen after these cells were seeded on Dynamatrix®. Endothelial cells play an important role in the formation of blood vessels and are a source of angiogenic cytokines. Exposure of these cells to DynaMatrix® may result in a positive angiogenic profile for both cytokines and matrix metalloproteinases (MMPs). Objective: The aim of this in-vitro study was to investigate if the exposure of human endothelial cells to the DynaMatrix® membrane would result in differences in the expression of cytokines and MMPs that play roles in angiogenesis. Materials and Methods: Human endothelial cells (HUVECs) were obtained from American Type Culture Collection (ATTC, Manassas, VA) and used in this study. Groups were established as follows: (a) Group 1: HUVECs seeded in culture media only, (b) Group 2: DynaMatrix® membrane incubated alone in the serum-media without any cells, and (c) Group 3: HUVECs seeded on DynaMatrix® membranes. After 72 hours of incubation, the conditioned media were collected and analyzed for the expression of 20 angiogenic cytokines and MMPs utilizing cytokine and MMP protein arrays. The density of each cytokine and MMP expressed was measured, averaged, and statistically analyzed by ANOVA. Results: Exposure of human umbilical vein endothelial cells (HUVECs) to the DynaMatrix® membrane resulted in a positive angiogenic profile for both cytokines and MMPs. Conclusion: This work furthers the evidence for the potential of DynaMatrix® to serve as a more predictable scaffold in RE.Item Epithelial expression of keratinocytes growth factor in oral precancer lesions(2016) Jimson, Sudha; Murali, S.; Zunt, Susan L.; Goldblatt, Lawrence I.; Srinivasan, Mythily; Department of Oral Pathology, Medicine and Radiology, School of DentistryBackground: Keratinocyte growth factor (KGF) is a potent epithelial mitogen that acts by binding the KGF receptors (KGFRs) expressed on epithelial cells and regulates proliferation and differentiation. The objective of this study was to investigate the expression of KGF in the epithelium in oral precancer. Materials and Methods: Archival tissues of oral submucous fibrosis (SMF) and leukoplakia were assessed for epithelial KGF expression by immunohistochemistry and real-time quantitative polymerase chain reaction. Results: KGF was predominantly expressed in the basal and parabasal cells in the epithelium of SMF tissues. KGF transcript in the epithelial cells increased with increasing severity of epithelial dysplasia in oral leukoplakia. Conclusion: Although widely reported as a product secreted by the mesenchymal cells, our data suggest that the KGF is also expressed in oral epithelial cells much like the expression in ovarian epithelial cells. Based on the localization of KGF in cells at the epithelial mesenchymal junction and that of the reported presence of KGFR in oral keratinocytes, a potential mechanism involving paracrine and autocrine interactions of KGF and KGFR in early stages of oral precancer is postulated.Item An in-vitro SEM study comparing the debridement efficacy of the Endoactivator™ system versus the Ultrasonic Bypass™ system following hand-rotary instrumentation(2010) Binkley, Steven Wayne, 1975-; Vail, Mychel Macapagal, 1969-; Spolnik, Kenneth Jacob, 1950-; Legan, Joseph J.; Zunt, Susan L.; Moore, B. KeithThe purpose of this study was to evaluate and compare the debridement efficacy of the EndoActivator (Dentsply Tulsa Dental, Tulsa, OK) versus the Ultrasonic Bypass system (Vista Dental) following hand-rotary instrumentation in anterior teeth. Sixty extracted human, maxillary anterior teeth were randomly assigned to three groups. Teeth were instrumented using (ISO k-flex) hand files and EndoSequence nickel-titanium rotary files (Brasseler, Savannah, GA) to a size 40/.06 taper. Group 1 served as the control group and had no additional treatment performed. Groups 2 and 3 were subjected to a final irrigating regimen that consisted of 6-percent sodium hypochlorite for a 1- minute duration. For group 2 the irrigation solution was activated for 1 minute using the EndoActivator system (DENTSPLY). For group 3, the irrigation solution was activated for 1 minute using the Ultrasonic Bypass System (Vista Dental). The teeth were then sectioned longitudinally and each half was divided into three equal parts 3 mm from the anatomic apex. The sample with the most visibly identifiable section of the apex was used for SEM evaluation. A scoring system to measure the efficacy of debris removal was utilized to quantify the results. Statistical analysis was performed using the Kruskal- Wallis test. If the overall test is significant, a Wilcoxon Rank Sum tests was used to compare each pair of groups. The results of this study indicate that both the EndoActivator and Ultrasonic Bypass groups had a smaller percentage of canal space occupied by smear layer and debris when compared with the control group at all three levels. This difference was statistically significant for the Ultrasonic Bypass System when compared with the control at both the coronal and middle thirds of the samples evaluated. This difference was not statistically significant in the apical third. When compared with the EndoActivator, the Ultrasonic Bypass System produced cleaner canals in the coronal and middle thirds, with the difference being statistically significant in the middle third only. These results of this research support the use of either of these two devices when compared with the controls. Smear layer removal and debridement efficacy was greatly increased when using either sonic or ultrasonic activation of sodium hypochlorite. More research is warranted concerning these two devices. Examining the antimicrobial efficacy with the use of these two devices could lend additional validation to their use in non-surgical endodontic therapy.Item Oral epithelial expression of angiotensin converting enzyme-2: Implications for COVID-19 diagnosis and prognosis(2020-06-23) Srinivasan, Mythily; Zunt, Susan L.; Goldblatt, Lawrence I.; Oral Pathology, Medicine and Radiology, School of DentistryThe severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) uses the angiotensin converting enzyme (ACE)-2 as the host receptor for target cell entry. The extent and distribution of ACE-2 has been associated with the clinical symptoms of coronavirus disease (COVID)-19. Here we show by immunofluorescence analysis that the ACE2 is abundantly expressed in oral mucosa, particularly in the surface epithelial cells suggesting that these cells could represent sites of entry for SARS-CoV-2. Further, together with the reports on ACE2 ectodomain shedding, we discuss the rationale for the hypothesis that the ACE-2 measurement in saliva could be a marker for COVID-19 infection during early phase following SARS-CoV-2 exposure.Item Reduction of enterococcus faecalis biofilm by blue light and sodium hypochlorite(2017) Kwan, Daryl A.; Gregory, Richard L.; Spolnik, Kenneth J.; Bringas, Josef S.; Zunt, Susan L.; Ando, Masatoshi; Ehrlich, YgalIntroduction: Microbial biofilms have been shown to be a cause of persistent endodontic infections. It is more resistant than planktonic bacteria to host immune defenses and antimicrobials. Studies indicate that photodynamic light therapy (PDT), which involves using light at specific wavelengths, has a potent antibacterial effect on bacterial biofilm. PDT is an antimicrobial strategy that involves the use of a nontoxic photosensitizer (PS) along with a light source. The excited PS reacts with molecular oxygen to produce highly reactive oxygen species, which induce injury or death to microorganisms. PSs have a high degree of selectivity for inhibiting microorganisms without negatively affecting host mammalian cells. PDT has been suggested as an adjuvant to conventional endodontic treatment. Studies at IUSD have shown that blue light at 380 nm to 440 nm has the ability to inactivate Streptococcus mutans biofilm without any exogenous PS. Objective: The objective of this study was to determine the effectiveness of blue light at 380 nm to 440 nm to reduce adherence of Enterococcus faecalis biofilm after NaOCl irrigation at various concentrations. Materials and Methods: E. faecalis biofilm was established for 72 hours in 96- well flat-bottom microtiter plates using Tryptic Soy Broth supplemented with 1.0-percent sucrose (TSBS). Biofilm was irradiated with blue light for 5 minutes before exposure to various concentrations of NaOCl for 30 seconds. A crystal violet biofilm assay was used to determine relative density of the biofilm. Data were analyzed with two-way ANOVA and Sidak-adjusted multiple comparisons using a 5.0-percent significance level. Null Hypothesis: Blue light and NaOCl will not have an effect against E. faecalis biofilm adherence. Results: Overall, there was a significant effect (p < 0.05) for NaOCl and a significant effect for blue light. The effects of the combination of NaOCl and blue light were also significant. Conclusion: We reject the null hypothesis and accept the alternative hypothesis that blue light when used in conjunction with NaOCl will reduce adherence of E. faecalis biofilm.