Dentistry School Theses and Dissertations
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Item An in Vitro Evaluation of an Experimental Composite Resin(1975) Elias, Augusto; Phillips, Ralph; Lund, Melvin; Katz, Simon; Goodacre, CharlesAn experimental polyurethane composite resin which was reported to have some adhesion to enamel was evaluated with respect to its potential to serve an anterior restorative material. A battery of physical tests were performed on this experimental resin which were considered pertinent to its performance as a restorative material. The values obtained for the experimental resin were compared to those obtained for a widely used commercial composite resin. The experimental composite resin was not superior to the commercial composite resin with respect to physical and mechanical properties. Although it is difficult to assess if differences in magnitudes observed with respect to strength, hardness, and water sorption would be reflected in clinical performance, past experience with enamel abrasion tests suggest that the experimental resin would be more susceptible to occlusal wear than the commercial resin. The bond strength and marginal leakage tests show that this material does not adhere to either enamel or dentin. In addition, problems were encountered with respect to handling characteristics. Thus, in essence, this experimental resin affords no advantage over current materials.Item Non-Carious Cervical Lesions: Bibliometric Insights, Detection Technology, Simulation Models and Prevention Strategy(2025-05) Denucci, Giovanna Corrêa; Hara, Anderson T.; Lippert, Frank; Platt, Jeffrey A.; González-Cabezas, Carlos; O'Toole, SaoirseThis thesis provides a comprehensive exploration of non-carious cervical lesions (NCCLs) through four distinct studies, each offering unique insights into their understanding, detection, progression, and prevention. Chapter 2 presents a bibliometric analysis that contextualizes NCCLs within the broader research landscape, revealing significant growth in publications and highlighting key contributors. The analysis categorizes studies into etiology, prevention, and therapy, uncovering a research gap in preventive measures. This chapter emphasizes the need for a shift from restorative treatments to proactive prevention and early detection. Chapter 3 advances the detection of NCCLs by evaluating the efficacy of intraoral scanners (IOS) as an alternative to traditional 3D optical profilometry. The study demonstrates that IOS technology can reliably quantify tooth structure loss, offering a promising tool for early detection and consistent monitoring in clinical practice. This chapter underscores the potential of IOS to facilitate timely interventions and improve patient outcomes. In Chapter 4, the focus shifts to the impact of erosive challenges and toothbrushing abrasion on the progression and morphology of NCCLs. The study reveals that acidic exposure accelerates tooth tissue loss and significantly alters lesion morphology. These findings provide clinicians with visual markers to differentiate between abrasion-driven and erosion-exacerbated lesions, enhancing diagnostic accuracy and guiding patient education on minimizing risk factors. Chapter 5 explores the preventive potential of dental adhesives under erosive and abrasive conditions. The study shows that certain adhesives can reduce the progression of NCCLs, particularly in their early stages. By demonstrating the effectiveness of these adhesives, this chapter offers a preventive tool for clinicians to protect at-risk patients, potentially extending the lifespan of tooth structures and reducing the need for invasive treatments.Item The design and use of dental articulators in the United States from 1840 to 1970(1970) House, James E.; Phillips, Ralph; Johnston, John F.; Standish, S. Miles; Van Huysen, Grant; Jordan, DavidGathered from United States Patent records, dental literature and personal communication are many bits of information concerning dental articulator use and design which have been put into this single source. It developes a new classification of dental articulators into eighteen types. This classification is based upon a sorting of mandibular movements recognized by the dental profession during one hundred thirty years of history from 1840-1970. Each classified type demonstrates how different designers of dental articulators tried to duplicate these jaw movements within mechanical devices. This investigation should be of interest to future designers of dental articulators since history proves that many designs are repeated several years after previous investigators have shown earlier like designs to be valueless. Also of interest is the magnitude of effort and thought by the many dental investigators of the past toward understanding mandibular movement and constructing mechanical devices to duplicate these movements. 235 United States Patent Letters applicable to dental articulators are reviewed in this thesis.Item Tap Water Filtration and Purification Usage and Their Impact on Fluoride Concentration - A Community-Based Study(2025-02) Hazzazi, Loai; Lippert, Frank; Soto Rojas, Armando E.; Martinez Mier, E. Angeles; Hara, Anderson; Maupomé, Gerardo; Nassar, Hani M.Water filtration and purification systems (WFPS) are a rapidly growing market aimed at improving water quality by removing harmful chemicals and bacteria. However, there is limited research on how WFPS affect fluoride concentrations, which are critical for preventing dental caries, as well as other essential minerals like calcium, magnesium, potassium, and sodium, which are vital for overall health. Our first aim was to assess the prevalence of WFPS use among residents of Indianapolis, Indiana, through a distributed questionnaire. Water samples were collected from participants to analyze fluoride, calcium, magnesium, potassium, and sodium. For the second aim, we replicated this study in Jeddah, Saudi Arabia, to compare findings across different geographic and cultural contexts. In the third aim, we conducted a laboratory study to test nine popular water pitcher filter brands for their effects on fluoride and other essential minerals. The results of the first aim of the study revealed that 71% of participants used some type of WFPS, with water pitcher filters being the most commonly used (31%). Additionally, reverse osmosis systems significantly reduced all studied minerals, while water softeners increased sodium concentrations. For the second aim, 60% of participants reported using WFPS, with reverse osmosis systems being the most commonly selected (62%). The findings also indicated that unfiltered tap water samples had very low fluoride levels, and reverse osmosis systems effectively reduced all tested minerals. The third aim demonstrated that water pitcher filters did not completely remove fluoride but had varying effects on the other studied minerals. In conclusion, in both locations, WFPS were widely used, but the types of systems preferred, and the mineral content of public water supplies varied. Our study also highlighted the importance of understanding the effects of different WFPS on essential minerals, especially fluoride, which plays a key role in preventing dental caries. These findings emphasize the need for further research to understand how WFPS impact both water quality and health outcomes, particularly in regions with differing water supplies and public health practices.Item The Antibacterial Effect of Electromagnetic Stimulation On In Vitro Endodontic Biofilms(2024-06) Whitfield, Tyler; Spolnik, Kenneth; Ehrlich, Ygal; Movila, AlexandruNon-surgical root canal treatment (NSRCT) is indicated for endodontic infection. However, it is generally indicated under conditions that have caused inflammation, infection, and/or necrosis of the pulpal tissue. In recent years, an electromagnetic stimulation (EMS) device has been created by the International Society for Electromagnetic Dentistry (Tominaga Dental Clinic, Naruto, Japan). This device transmits electromagnetic waves and is used to augment the disinfection of the RCT. This novel method may accomplish the RCT disinfection by creating a synergistic reaction via thermal and electrical energy, allowing the potential to enhance root canal disinfection [2, 3]. Japanese researchers have also found promising results with its synergistic use clinically [4, 5]. Previous results have shown an increased anti-microbial effect with synergistic use of sodium hypochlorite, but this study will explore the direct anti-microbial effect of electromagnetic stimulation.Item The Effects of Two rhPDGF-BB Applications on Periodontal Ligament Cell’s Proliferation and VEGF Expression(2024) Velgis, Raziel; Windsor, L. Jack; John, Vanchit; Batra, Chadni; Batra, Chandni; John, Vanchit; Batra, Chandni; Windsor, JackBackground: Platelet derived growth factor (PDGF) has been shown since the late 1980s to play a major role in periodontal regeneration. PDGF has five isoforms and the isoform PDGF-BB has been found to be the most effective. Animal studies evaluating release kinetics of purified recombinant human platelet-derived growth factor (rh-PDGF-BB), demonstrated that 90% of rh-PDGF-BB was depleted from sites within 72 hours after implantation. Thus, the aim of this in-vitro study was to evaluate the effects of two rhPDGF-BB applications on periodontal ligament fibroblasts proliferation and VEGF expression. Materials & Methods: Periodontal ligament (PDL) cells were seeded in multiple 6 well plates and split into 3 groups. Group 1 served as a control that received no rh-PDGF-BB. Group 2 was given an initial dose of 10 ng/ml rhPDGF-BB on day 1 and none on day 3. Group 3 received a dose of 10 ng/ml rhPDGF-BB on day 1 and a second dose on day 3. On day 3, half of the plates were stopped and media collected was used for LDH, WST-1 and VEGF ELISA analysis for evaluation of VEGF expression, cellular proliferation and cytotoxicity. Plain media was then added to groups 1 and 2 while group 3 received media with rh-PDGF-BB. On day 6, the collected media was used for ELISA, WST-1 and LDH assays. Results: PDL cell proliferation was not significantly different between any group studied (p=0.689). VEGF expression was increased in group 2 and 3 on day 3 compared to group 1 (p=0.005). There was no difference between groups 1 and 2 on day 6 (p=0.977). Conclusion: The addition of rhPDGF-BB to PDL cells did not increase proliferation at any time point. A single application of rhPDGF-BB increased the expression of VEGF from PDL cells; however, an additional application did not significantly increase the expression of VEGF.Item Shear Bond Strengths Of A Two-Step Self-Etch Adhesive And A Three-Step Etch-And-Rinse Adhesive In Artificial Dentin Caries Lesions Of Various Depths: An In Vitro Study(2024-07) Buechele, Ryan W.; Cook, Norman B.; Diefenderfer, Kim E.; Capin, Orian R; Sochacki, Sabrina F.; Strother , James M.Background: Minimally invasive caries management philosophy advocates leaving carious dentin as a substrate for adhesive bonding. However, the performance of current resin adhesives in incompletely excavated caries lesions is unknown. Understanding the limitations of bonding to carious dentin is critical for the restoring clinician. Objective: To compare the shear bond strengths of a two-step self-etch adhesive and a three-step etch-and-rinse adhesive to moderate and severe artificial dentin caries. Methods: 96 bovine incisors were prepared and assigned to experimental groups of moderate or severe artificial dentin caries lesions or control groups (sound dentin). Specimens were randomly assigned to a two-step self-etch (Clearfil SE Bond 2) or three-step etch-and-rinse (OptiBond FL) adhesive for bonding to a nanohybrid composite resin. TMR analysis determined lesion depth. Specimens were stored for 30 days in Millipore water (5oC), shear bond strengths were measured, and failure modes observed. Two-way ANOVA with interactions evaluated the effects of adhesive type and demineralization severity on shear bond strength. Failure modes were compared using ordinal logistic regression. A two-sided 5% significance level was used for all tests. Results: Clearfil SE performed significantly better than Optibond FL in both moderate and severe lesions. Both adhesives performed adequately on sound dentin, but poorly in severe lesions. For OptiBond FL, bond strengths were lowest in moderate lesions; failures were predominantly mixed or cohesive within composite resin in both moderate and severe lesions, as well as in sound dentin specimens. For Clearfil SE, bond strengths were lowest in severe lesions; failures were predominantly adhesive in moderate lesions, cohesive within composite resin in severe lesions, and mixed adhesive/cohesive in sound dentin specimens. Discussion: Bonding to demineralized dentin was highly variable for both adhesives. Bonding to sound dentin yielded higher bond strengths. Conclusions: A three-step etch-and-rinse adhesive did not perform better than a two-step self-etch adhesive in this study. A self-etch adhesive may be the better choice when bonding to demineralized dentin. Either adhesive may be acceptable when bonding to sound dentin.Item Bactericidal Efficacy of EdgePRO Er,Cr:YSGG Laser-Activated Irrigation Against a Mature Endodontic Multispecies Biofilm Using an in vitro Infected Tooth Model(2024) Patterson, Samuel B.; Spolnik, Kenneth J.; Gregory, Richard; Ehrlich, Ygal; Movila, AlexandruIntroduction: Treatment goals of non-surgical root canal therapy (nsRCT) include the removal of all organic tissue material, bacterial biofilm and their by-products, and debris materials, in order to disinfect the canal system to a level compatible with healing and to further prevent infection. Standard chemo-mechanical protocols have several well-documented shortcomings and subsequent areas for improvement regarding their disinfection abilities. In recent years, emerging laser technology and its application in root canal therapy has been gaining popularity as a safe and promising tool for advancing endodontic treatment. The newest FDA-approved laser for endodontic application is the EdgePRO Erbium,Chromium-doped:Yttrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) infrared laser operating at a 2780 nm wavelength. Previous in vitro studies using Er,Cr:YSGG lasers have demonstrated their ability to enhanced canal debridement, cleaning, smear layer removal, and bacterial disinfection. Additionally, a few in vivo trails have been completed using this laser type as an adjunct in RCT procedures, which have yielded safe and highly successful results in the clinical setting. However, research specifically using the EdgePro device as well as a standardized protocol for optimal clinical usage of the laser is lacking. Objectives: The aim of this study was to evaluate the bactericidal and biofilm dissolution effects of laser-activated irrigation using the EdgePro laser against a mature multispecies biofilm in an infected tooth model and to assess the potential increased disinfection and cleaning ability compared to a standard needle irrigation protocol. Materials and Methods: Single rooted teeth (n=36) were decoronated to a standardized length of 16mm. The root canals were endodontically prepared using a standard irrigation, hand-filing, and rotary protocol to a final size of ISO 25.06 while maintaining a fully patent apical foramen. An irrigation solution reservoir was created in the coronal 4 mm of the canal space. Sterile specimens were inoculated with multispecies bacterial sample containing E. faecalis. The mixed bacteria was grown anaerobically for 10 days to form a mature biofilm using a previously established protocol. The teeth were divided into a negative control group (saline rinse, n=12), positive control group (standard needle irrigation – SNI, n=12), and an experimental group (laser-assisted treatment protocol, n=12). The positive control and experimental laser groups utilized the same irrigation solutions of 2 mL 17% EDTA followed by 5 mL 3% NaOCl using a standard 27-gauge side-vented irrigation needle placed as far apically as possible without binding. The experimental group underwent additional laser activation using laser tip #2 (350 m diameter) and settings of: 15 mJ, 0.75 W, 50 Hz, 0% air, and 0% water spray (Mid-Root Solutions 1 preset). The laser tip was inserted halfway into the irrigation filled canals (8 mm from orifice and apex) and fired upon withdrawal at a speed of 0.8 mm/sec, which comprised a single lasing cycle of 10 seconds. Three lasing cycles were completed with EDTA first followed by NaOCl, for a total of six lasing cycles with 60 seconds of irradiation time per tooth. A final rinse of sterile saline was used in all tooth samples prior to bacterial sample collection via Versa-brushes and sterile paper points. The samples were transferred to a laboratory setting where they underwent ultrasonic agitation, serial dilution, spiral plating on blood-agar, and two days of anaerobic incubation for assessment of bacterial growth. Colony forming units (CFUs/mL) were counted as a means of quantitative analysis. Results: The negative control group yielded the highest level of bacterial growth with an average of 934,771 CFUs/mL. The positive control group displayed a statistically significant lower amount of bacterial growth with an average of 4,698 CFUs/mL and yielded 1 sample with no bacterial growth. The experimental laser group had statistically significant lower bacterial growth present compared to both the positive and negative control groups and produced all negative bacterial samples with none of the 12 agar plates demonstrating CFU growth and averaged 0 CFUs/mL.. Conclusion: Within the scope of this study, laser-activated irrigation (LAI) using the EdgePro Er,Cr:YSGG laser was capable of producing no detectable bacterial samples in an in vitro infected tooth model. EdgePro LAI displayed statistically significant superior cleaning and disinfection of infected canal space compared to teeth treated with standard needle irrigation alone. The EdgePro laser system indeed shows promise as an adjunctive tool in clinical root canal treatment procedures. Further investigation is warranted using similar protocols in teeth with more complicated anatomy and with supplemental methods for analyzing bactericidal potential.Item Effectiveness of GentleWave CleanFlow on Multispecies Endodontic Biofilm Removal in Single Rooted Extracted Teeth(2024-06) Beswick, Adam J.; Spolnik, Kenneth J.; Movila, Alexandru; Gregory, Richard L.; Ehrlich, YgalIntroduction: One of the challenges of non-surgical root canal treatment is disinfection. Bacterial biofilms adhere to canal walls and invade the intricate anatomy present within root canal systems. Traditional irrigation methods are unable to deliver irrigation solutions to all parts of the canal system. The GentleWave system is an advanced irrigation method designed to improve irrigation and disinfection, ultimately leading to more successful root canal outcomes. Objective: The aim of this study is to evaluate the GentleWave CleanFlow posterior instrument’s ability to remove a multispecies biofilm from a single canaled extracted tooth compared to traditional irrigation techniques. Materials and Methods: Thirty-six single rooted premolar teeth with single canals were prepared to a uniform size, instrumented to size 25.06 and inoculated with a multispecies bacterial biofilm taken from an adult tooth with pulpal necrosis. Teeth were incubated and biofilm established before teeth were disinfected. Three disinfection groups included: GentleWave irrigation using the Posterior CleanFlow Procedure Instrument on the necrotic tooth cycle, standard needle irrigation with 2.5% NaOCl and 8% EDTA, and needle irrigation with sterile water. Following treatment, canals were swabbed and plated on blood agar plates and incubated for 48 hours when colony forming units were counted. Results: Both GW and standard needle irrigation demonstrated significantly lower CFU/mL than the negative control (p<0.001). However, the GW and positive control groups were not significantly different from one another (p=0.132). Conclusion: The findings of this study suggest that the GentleWave Posterior CleanFlow procedure instrument does not exhibit improved biofilm removal compared to standard needle irrigation. However, based on mixed results when comparing this study to previous GentleWave biofilm removal studies, it is clear that more research is necessary. Future studies should considering using a multispecies biofilm, the GentleWave CleanFlow procedure instrument and multiple techniques to assess biofilm removal.Item The Effect of Bonded Orthodontic Appliances on Salivary Mutans Streptococci and on Immunoglobulin A Antibody to S. Mutans(1997) Wittler, Michelle L.; Gregory, Richard L.; Switalski, Lech M.; Miller, Chris H.; Garetto, Lawrence P.; Shanks, James C.The placement of fixed orthodontic appliances creates a number of new retention sites in the oral cavity, which subsequently leads to an increase in the number of cariogenic bacteria, including Streptococcus mutans, during active orthodontic treatment. We hypothesize that the increased prevalence of S. mutans in the saliva of orthodontic patients provides an antigenic challenge to the mucosal immune system, which leads to an elevation of secretory IgA (sIgA) antibodies to S. mutans in saliva. The purpose of this study was to evaluate the change in numbers of salivary mutans streptococci and the concentration of parotid sIgA antibody to S. mutans with the placement of bonded orthodontic appliances. A randomly selected group of 19 patients requiring the placement of orthodontic appliances was tested in this study. Whole and parotid saliva samples were collected three times prior to bonding and four times during bonded appliance therapy over a 30-week period. Whole saliva samples were spiral plated on mitis salivarius sucrose agar and mitis salivarius sucrose bacitracin agar in order to quantify total oral streptococci and mutans streptococci, respectively. Parotid saliva was assayed for IgA antibody to S. mutans using an established ELISA technique. The results demonstrated a significant (p < 0.05) increase in total oral streptococci and mutans streptococci numbers after six months of orthodontic treatment when compared with the baseline values. The level of sIgA to the clinical isolates of S. mutans was also significantly higher six months after the cementation of orthodontic appliances. These elevated numbers of mutans streptococci elicited a mucosa! immune response, which corresponded with a higher concentration of sIgA to S. mutans in the saliva. There was a significant negative correlation (R = -0.22; p = 0.02) between the numbers of mutans streptococci and sIgA antibody levels to the clinical isolates of S. mutans. When the sIgA antibody levels were elevated the numbers of mutans streptococci were lower. These data suggest that sIgA antibody to S. mutans may be a protective mechanism against an elevated level of mutans streptococci caused by the placement of orthodontic appliances. If the mucosal immune response to S. mutans could be enhanced before bonding orthodontic appliances, this could prevent some of the demineralization found adjacent to bands and brackets.