Theses and Dissertations School of Dentistry: Recent submissions
Now showing items 1-20 of 250
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A Cadaver-based Comparison of Sleeve-guided Implant-drill and Dynamic Navigation Osteotomy and Root-end ResectionsThe purpose of this study was to compare the accuracy and efficiency of fully guided static and dynamic computer-assisted surgical navigation methods for osteotomy and root-end resection (RER). Fifty root specimens from cadaver heads were divided into two groups: fully guided static computer-assisted endodontic microsurgery (FG sCAEMS) and dynamic computer-assisted endodontic microsurgery (dCAEMS) (n=25). Cone-beam computed tomography (CBCT) scans were conducted before and after the surgery. Osteotomy and RER were virtually planned in the preoperative CBCT scan. Endodontic microsurgery was executed with the guidance of 3D-printed surgical guides in FG sCAEMS and a 3D-dynamic navigation system in dCAEMS. Analysis involved calculating 2D and 3D deviations as well as angular deflection. Additionally, osteotomy volume, resected root length, and recording osteotomy and RER time were measured. The number of procedural errors were recorded. FG sCAEMS demonstrated comparable accuracy to dCAEMS, with no significant difference in 2D and 3D deviation values or angular deflection (P > .05). FG sCAEMS led to reduced osteotomy and RER times (P < .05). However, FG sCAEMS exhibited a higher incidence of incomplete RERs compared to dCAEMS. Osteotomy volume, RER angle, and resected root length were similar in both groups (P > .05). Overall, both FG sCAEMS and dCAEMS proved to be viable options for performing osteotomy and RER. Within the constraints of this study based on cadaver samples, FG sCAEMS demonstrated comparable accuracy to dCAEMS and both methods were efficient for performing osteotomy and RER.
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Clinical Investigation of the Impact of Endodontic Disinfection on the Bacteriome of Root Canal Infection Using Next-Generation Sequencing on the Illumina MiSeq PlatformThe primary cause of root canal infection is bacteria and their by-products, making disinfection of the root canal system a key goal in endodontic therapy. However, the complex anatomy of root canal systems, particularly the isthmus and its ramifications, poses challenges for effective disinfection. Currently, no disinfection protocol can eliminate all bacterial contents from root canal infections, driving the ongoing search for an optimal disinfection approach. Recently, next-generation sequencing (NGS), particularly the Illumina MiSeq platform, has been widely explored in endodontic infections due to its low sequencing error rates, cost-effectiveness, and high-quality reads. Leveraging advanced sequencing techniques to reveal the bacteriome of root canal infections and assess the impact of current disinfection methods could enable the development of more targeted and effective disinfection protocols. This dissertation presents an interventional clinical study aiming to investigate the diversity and composition of the bacteriome in primary endodontic infection (PEI) with apical periodontitis (AP) and evaluate the impact of root canal disinfection on the endodontic bacteriome using NGS on the Illumina MiSeq Platform. First, we characterized the bacteriome in PEI with AP, identified core and rare bacteriome species, and analyzed community diversity metrics using the Illumina MiSeq platform. Our results showed that Bacteroidetes, Firmicutes, Synergistetes, Fusobacteria, and Actinobacteria were the most abundant bacterial phyla. We identified 113 genera and 215 species. Analysis revealed differences in abundant taxa among distinct age, gender, symptomatology, and lesion size groups. These findings suggest that the bacteriome in PEI with AP is complex and has high microbial heterogeneity among patients. Moreover, age, gender, symptomatology, and lesion size might play a role in the abundant taxa present in PEI with AP. Second, we determined quantitatively and qualitatively the impact of chemomechanical preparation (CMP) using 2.5% sodium hypochlorite (NaOCl) on the bacteriome found in PEI with AP using the Illumina MiSeq platform. Our findings demonstrated a distinct community composition and increased alpha diversity after CMP using 2.5% NaOCl, despite a significant decrease in bacterial abundance. We observed differential enrichment of specific taxa, including Stenotrophomonas_unclassified, Enterococcus_unclassified, and Actinomyces_unclassified, suggesting lower effectiveness of CMP using 2.5% NaOCl against these taxa. Findings from this dissertation highlight the complexity and heterogeneity of the bacteriome in PEI with AP, emphasizing the influence of patient-related factors on microbial diversity. The research highlighted the limited effectiveness of current endodontic disinfection protocols, specifically the use of 2.5% NaOCl, in reducing bacterial abundance while revealing limitations against certain taxa. These insights provide a foundation for developing more targeted and effective disinfection strategies, potentially leading to improved outcomes in endodontic therapy.
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Impact of SARS-CoV-2 Salivary Gland Infection on the Production of the Antifungal Peptide Histatin-5, Candida Colonization, and the oral Microbiota.Despite the myriad oral manifestations during COVID-19 and presence of SARS-CoV-2 in saliva, the oral cavity remains an underappreciated site. However recent findings have shown that SARS-CoV-2 can replicate in salivary gland cells, leading to inflammation and tissue destruction. Saliva contains antimicrobial peptides considered integral components of innate immunity crucial for oral health, with the most notable being histatin-5. This peptide is exclusively produced in salivary glands and exhibits unique potent antifungal activity against Candida albicans. In this dissertation, we discovered that destruction of salivary gland by SARS-CoV-2 can compromise histatin-5 production, predisposing patients to oral candidiasis and dysbiosis in the oral microbiome. First, we utilized our novel customized immunoassay to measure salivary histatin-5 levels in a prospective study involving stratified COVID-19 cohorts. Our data indicates a trend showing a decrease in salivary histatin-5 and increase in Candida during COVID-19, persisting post-COVID-19 recovery, potentially contributing to the long COVID-19 syndrome. To provide lacking mechanistic insights into the pathophysiology of salivary gland dysfunction during COVID-19, we performed in situ hybridization coupled with immunofluorescence to co-localize SARS-C0V-2 and histatin-5, respectively, in salivary gland tissue from deceased COVID-19 patients. Our findings indicated diminished or absent histatin presence in salivary gland acini with proliferating SARS-CoV-2 providing the first direct evidence associating SARS-CoV-2 with histatin-5 production. Next, we conducted a comprehensive metagenomic analysis on clinical oral samples and identified potential COVID-19 associated pathologic dysbiotic shifts in the oral microbiome. Lastly, we conducted in-vitro experiments coupled with scanning electron microscopy and confocal imaging to identify the effect of histatin-5 on candida cells and biofilm concluding the antifungal effect of histatin-5 on candida albicans. This clinical study clearly shows the effect of SARS-CoV-2 on oral microbiota, highlighting the importance of understanding and managing the complex dynamics within the oral cavity of COVID-19 patients.
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Enhancing Cervical Composite Restorations ManagementThe management of cervical composite restorations, also known as Class V restorations, represents a challenge in contemporary dentistry. This difficulty arises from the complex nature of cervical lesions and unfavorable location, close to soft tissues prone biofilm accumulation. Additionally, cervical composite restorations have significant failure rates, further complicating their management and longevity. The etiological factors contributing to cervical cavitation are diverse, ranging from mechanical trauma, abrasion, and erosion leading to non-carious cervical lesions (NCCLs), to cariogenic biofilms responsible for root caries. The combination of these factors, high failure rates, varied etiology, and the technical difficulty of restoring dentin-margin cavities underscores the need for advanced understanding of proper management and techniques in treating cervical composite restorations. This master thesis is presented in chapters with the following aims: 1) perform a scoping review as a preliminary assessment to identify how restorative protocols (surface pre-treatment, such as etching with different agents and techniques, like bevel) influence the longevity outcome of non-carious cervical lesions (NCCLs) restorations, and, 2) to comprehensively analyze and compare the biofilm composition grown over healthy and cavitated root caries lesions in two distinct age groups: patients younger than 65 years old (healthy and cavitated) and those older than 65 years old (healthy and cavitated). As the methodology approached, the scooping review and clinical studies were performed according to the cited objectives. For the results, a collective of the literature showed that the most frequently dentin pretreatment method studied was 'Application mode - Etching', with over 35% of studies focusing on this area, followed by 'Application mode - Adhesive' in 34% of the studies. 'Pre-treatment of surface with substance' was the focus of around 14% 'Pre-treatment of surface with lasers' accounted for approximately 11% of studies (Chapter 1.) In our clinical study the analysis of predominant bacteria in control and cavitated root caries lesions across two age groups (<65 years old and >65 years old) reveals notable variations in microbial composition. Cavitated lesions exhibit higher bacterial diversity compared to control ones, as indicated by the Shannon diversity index, suggesting a more complex microbial ecosystem within these lesions. Furthermore, the Simpson's dominance index suggests that control lesions are characterized by a few dominating species, contrasting with the more evenly distributed bacterial community in cavitated lesions. Age-related differences further modify these patterns, with older individuals displaying distinct bacterial profiles. These findings underscore the impact of lesion type and patient age on the oral microbiota's diversity and dominance, highlighting the complexity of microbial ecosystems in root caries lesions. (chapter 2)
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Comparison of Virtual Treatment Setup among Clear Aligner CompaniesOver the past two decades, clear aligner therapy grew as an alternative to traditional brackets for orthodontic treatment. Recently, several orthodontic companies introduced their clear aligner brands, each with unique features such as material type and thickness, gingival trim design, specific auxiliary tools, and different strategies for guiding orthodontic movement. However, little is known about how these features impact their virtual treatment setup. This study aimed to compare the virtual treatment setups among five clear aligner companies to assess their differences. The initial records of 10 patients, including extra and intraoral photos and scans, were submitted to Invisalign®, ClearCorrect®, 3M™ Clarity™, Spark™, and Reveal® clear aligner systems. Each case prescription was standardized to ensure comparable treatment plans across the companies. The comparison focused on the number of aligners, number of attachments, amount of interproximal reduction per arch, planned extrusive or intrusive movement of maxillary central incisors, final canine and molar relationships, final intercanine and intermolar widths, and planned expansion or constriction of the intercanine and intermolar widths. Results indicated significant differences in the virtual treatment setups for the same patient among clear aligner companies in the number of aligners (p-value = 0.003), number of attachments (p-value < 0.001), and predicted final canine relationship (p-value = 0.013). However, no statistical differences were observed in the other variables evaluated. ClearCorrect® stands out by prescribing the fewest number of aligners and attachments, whereas 3M™ Clarity™ tends to prescribe the highest number of aligners and attachments. There is a notable deficiency across companies, particularly with ClearCorrect® and Spark™, in planning for a final bilateral canine Class I relationship. These findings suggest that the unique characteristics of each aligner company lead to distinct approaches in treating the same patient, highlighting both areas of discrepancy and consistency in the virtual treatment setups.
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Comparing Accuracy of Commonly used Final Impression Techniques in Recording Excessively Movable Tissues in Completely Edentulous Patients.Purpose Traditionally several impression materials and techniques utilizing custom tray with a window have been proposed to record excessively movable tissues. These procedures are meant to produce very minimal if not no compression of the tissues during the process of impression to avoid any tissue distortion. Although studies have shown compression on tissues can be minimized, a technique that can completely eliminate the pressure is not proven. This study focuses on comparing accuracy of impression techniques that use common impression materials which produce minimal tissue displacement using digital intra oral scan as a reference. Materials and methods This is an in vivo clinical study on a cohort of 14 edentulous patients that presented with excessively movable tissues. An intra oral scan of the edentulous ridge was obtained using Medit i700 scanner (Medit Corp, Seoul Korea). Final impressions were made in light body vinyl polysiloxane (Dentsply Sirona Milford, Delaware) after the tissues were border molded with Type 1 modelling plastic compound (Kerr Corporation, Orange, CA) in a conventional custom tray and a custom tray with a window (Zahn, Melville NY). The impressions were scanned using 3Shape D2000 (3M Shape Copenhagen, Denmark) desktop scanner. These files were imported into Geomagic Control X software (Geomagic Control X; 3D Systems, Rock Hill, SC). The STL (standard tessellation language) files of final impression with conventional tray and tray with a window were aligned to the intra oral STL scan file using best fit alignment. The areas of interest (anterior region, palate and tuberosity) were delineated for three-dimensional comparison. Root mean square (RMS) values describing deviations in impression techniques were obtained and compared using Two-Way ANOVA followed by Tukey HSD posthoc analysis. Each subject served as their own control as the study compared tissues recorded with 3D surface scans to impressions using vinyl polysiloxane. A p<0.05 was considered significant. Results There was no significant difference in the RMS values between the two impression techniques that used conventional tray and tray with a window studied in terms of their deviation from the intra oral scan (p=0.56). However, there was significant difference between the areas tested in terms of deviation from the intra oral scan (p=0.0049). The tuberosity area in the open tray impression showed deviation with a mean difference of -0.12 RMS value when compared to the anterior area in the closed tray impression (p=0.002). The anterior area in the closed tray impression showed deviation with a mean difference of +0.1012 RMS value when compared to the palatal area in the closed tray impression (p=0.013) Finally, the anterior area in the closed tray impression showed deviation with a mean difference of 0.106 RMS value when compared to the tuberosity area in the closed tray impression (p=0.01). The Tukey HSD posthoc analysis demonstrated that there was no significant difference between all other groups (p>0.05). There was also no significant interaction between impression technique and area (p=0.46). Conclusion There were no significant differences in the tissue displacement when final impressions made with conventional closed tray and tray with a window were compared to intra oral scan. However, there were significant differences in tissue displacement between areas compared in a conventional closed tray, where anterior area consistently showed more displacement compared to palate and tuberosity. Lastly there was no significant interaction between the two variables impression technique and areas. Therefore, final impression in a custom tray with window can minimize displacement of excessively movable tissues in comparison to a conventional closed tray.
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Assessing language use patterns for terminology to describe bimaxillary protrusive phenotypesObjective: This study aimed to evaluate orthodontists’ terminology use for characterizing dentoalveolar segments and jaws that are prominently positioned relative to the cranium. Methods: An 11-item survey was distributed to orthodontists worldwide. Participants were asked to rate their preference for the terms “bimaxillary protrusion,” “bimaxillary dentoalveolar protrusion,” “bidental protrusion,” “bialveolar protrusion,” and “bidentoalveolar protrusion” in general, as well as in reference to lateral cephalograms that depicted various combinations of dentoalveolar and jaw protrusion. Results: Respondents most preferred “bimaxillary protrusion,” followed by “bimaxillary dentoalveolar protrusion,” to describe lateral cephalograms with dentoalveolar protrusion, with or without jaw protrusion. They did not consider a phenotype with only protrusion of apical jaw bases as bimaxillary protrusive. Moderation analyses found that older respondents were more likely to use “bidentoalveolar protrusion” for a phenotype with both jaw prognathism and protrusive teeth and “bidental protrusion” for a phenotype with normally positioned jaws with dentoalveolar protrusion. Non-native English speakers were overall more likely to prefer the term “bimaxillary dentoalveolar protrusion.” Conclusions: Respondents generally showed a strong preference for “bimaxillary protrusion” over other terms to describe dentoalveolar protrusion and did not consider bimaxillary prognathism in the absence of dentoalveolar protrusion as bimaxillary protrusive.
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Saliva Levels of IL-18 in Healthy and Peri-implantitis PatientsTitle of Thesis: Saliva Levels of IL-18 in healthy and peri-implantitis patients Purpose: Peri-implantitis is a common problem that occurs in 9.25% in functioning implants and approximately 20% of patients. Our understanding of the etiology of Peri-implantitis is limited. Understanding molecular mechanisms associated with peri-implantitis may help in developing and improving treatments for peri-implantitis. The purpose of this study was to assess the levels of IL-18 in saliva of healthy patients and patients diagnosed with peri-implantitis. Materials and Methods: Institutional Review Board approval was obtained. Unstimulated saliva was collected from a total of 24 subjects (peri-implantitis n=14, healthy n=10). Saliva was collected from subjects using 15 ml tubes every minute for 5 minutes. Collected saliva were then centrifuged for 5 minutes at 10,000 x g. The aliquot layer was collected and immediately stored at -80°C until analysis. The concentration level of IL-18 was measured using high-sensitivity enzyme-linked immunoabsorbent assays (ELISA). All statistical analyses were performed using Microsoft® Excel®. Statistical comparisons were tested for normality followed by the Mann Whitney U test. Results: Twenty-four subjects with 33 implants were analyzed. Twenty-two implants were diagnosed with peri-implantitis, while the remaining 11 were healthy controls. The Median values of IL-18 analytes were 1.92 pg/ml for peri-implantitis and 2.23 pg/ml for healthy control. The range was 8.58 pg/ml for peri-implantitis (min 0.079 pg/ml – max 8.66 pg/ml). The range was 21.26 pg/ml for healthy control (min 1.13 pg/ml – max 22.39 pg/ml). The mean was 5.47 pg/ml for healthy control and 2.61 pg/ml for peri-implantitis. The standard deviation was 6.80 pg/ml for healthy control and 2.04 pg/ml for peri-implantitis. Conclusions: In non-smoking patients not suffering from diabetes or other inflammatory disease, it appears that the levels of IL-18 are comparable to those of healthy patients.
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Extra! Extra! Read All About It: A National Dental Survey of the Emergency Room PhysicianIntroduction: Physicians are the first point of contact for patients who present to the ED with dental pain, infection, and trauma. This study determined the Physician's knowledge gap when assessing and rendering care to the ED dental patient. Methods: 81 American College of Emergency Physicians (ACEP) ED physician members were surveyed online using Qualtrics.TM The sample group was questioned about their comfort level when assessed and rendered care for dental pain, infection, and trauma. If satisfied with support when assessed and rendered, Chi-square and Fisher’s exact test analysis was undertaken using contingency tables. Results: The survey associated assessment and rendered care for dental trauma and severe local odontogenic infection. This is influenced by satisfaction with dental education (10x odds more comfortable), years in practice, and ACEP affiliation. Conclusions: This survey presented an opportunity for advancement in physician management of trauma and infection. Continuing medical education courses for ED physicians with dental emergencies could include instruction and guidelines on assessing and rendering care for dental trauma and severe dental disease.
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Impact of Clear Aligners on the Risk of Biofilm-Induced Oral DiseasesThe increasing demand for clear aligners in orthodontics over the past decade reflects patients' preferences for simplicity and more comfortable treatment options. As clear aligners become more prevalent, there is a growing interest in understanding the physiological and microbial alterations accompanying their use. In light of these findings, it is crucial to guide orthodontists and general dentists in managing clear aligner cases regarding the impact on the risk of biofilm- induced oral diseases. Here, this master thesis is presented in chapters with the following aims: 1) perform a scoping review as a preliminary assessment of whether clear aligners are associated with a higher, lower, or similar risk of biofilm-related oral health issues such as dental caries and periodontal disease, and, 2) to investigate the microbiome change of clear aligners users as a relevant factor for caries development or periodontal diseases. As the methodology approached, the scooping review and cohort studies were performed according to the cited objectives. For the results, a collective of the literature showed a 58% similar risk of biofilm-inducing diseases for users of clear aligners and fixed appliances. For 17% of studies, clear aligners have shown reduced risk (chapter 1). 59% of these studies, considering clear aligner users, investigated periodontal diseases and the main biofilm-induced disease. In our clinical study, no significant differences were detected over time . At the genus level, after 30 days demonstrated significantly increased Bacillus abundance and decreased Prevotella abundance. Our results suggested that the general biodiversity and salivary microbial community structure did not change significantly and that patients had increased beneficial oral hygiene habits and awareness during the first six months of Invisalign treatment. (chapter 2). Key words: Orthodontics, Oral biofilms, Clear Aligners, Biofilm-related diseases.
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Comparison of Feldspathic Veneer Surface Treatments on Color Stability after Debonding of Orthodontic Brackets: An In Vitro StudyObjectives: To analyze the color stability of feldspathic porcelain veneers treated with different surface preparation methods after bonding/debonding orthodontic brackets. Materials and methods: 25 feldspathic porcelain veneers samples were divided into groups according to surface treatment procedures: (S) glaze-layer retained; (SHF) hydrofluoric acid etch; (SOXA) sandblasting; (SB) diamond burs; and control (C). Specimens were primed using silane and brackets were bonded. After removal of brackets, Color stability (NBS score) was determined following coffee staining for 21 days. Results: No significant interclass difference was identified between overall color stability for the four test groups (S, SHF, SOXA and SB). All test groups showed a statistical significant increase in color change compared to the control. Conclusions: Surface treatment resulted in a significant decrease in color stability with no statistical difference between treatments. Regardless of surface preparation method, bonding and debonding of orthodontic bracket results in decreased color stability of feldspathic porcelain veneers.
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Post-traumatic Hyperalgesia and Degeneration of Temporomandibular joints in mice: the role of nociceptive afferentsTrauma to the temporomandibular joint (TMJ) can increase the incidence of developing temporomandibular disorder (TMD), and there is some controversy regarding the relationship between TMJ pain and degeneration. Considering the clinical implications of pain management, it is important to recognize whether it can affect the prognosis of TMJ degeneration. Recent studies have demonstrated that nociceptive afferents participate in bone remodeling via several pathways, suggesting that these afferents may be involved in both the perception of pain and the structural modulation of the TMJ. The specific impact of nociceptive afferents on TMJ pain and degeneration, however, remains ambiguous. We utilized the forced mouth opening (FMO) model on mice to address this issue. The FMO model resulted in increased mechanical hyperalgesia, as measured by the Von Frey (VF) test, spontaneous pain-like behaviors observed through the mouse grimace scale (MGS), and anxiety-like behaviors ascertained by the open-field test (OFT). These symptoms align with clinically relevant pain conditions such as spontaneous, mechanical, and function-evoked pain. Most TMJ afferents in the TG were small peptidergic neurons expressing calcitonin gene-related peptides, whereas non-peptidergic TMJ afferents were comparatively scarce. Additionally, the FMO induced thinning of the condylar cartilage and degeneration of the subchondral bone, corroborating the model's ability to replicate post-traumatic hyperalgesia and TMJ condylar degeneration. Chemogenetic silencing of TRPV1-lineage afferents, using an inhibitory designer receptor exclusively activated by designer drugs (DREADD), lessened spontaneous pain-like behaviors but did not affect mechanical hyperalgesia in the skin overlying the TMJ. This silencing also modestly reduced FMO-induced subchondral bone degeneration without impacting cartilage degeneration. Our findings imply that TRPV1-lineage afferent fibers may not be the main factor in condylar degeneration following TMJ injury. Conclusively, our study results endorse the FMO model as a clinically relevant and translational approach for investigating post-traumatic, pain-like behaviors. Moreover, manipulating the TMJ nociceptive terminals may be effective in treating pain without aggravating degeneration after injury.
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Novel Bioactive Low-Shrinkage-Stress Composite with Antibacterial and Remineralization PropertiesMethacrylate-based resin composites are frequently employed in dentistry for their aesthetic qualities, durability, and adhesive properties. Nevertheless, these restorations generally exhibit a lifespan of 5 to 10 years, with recurrent caries and tooth fractures being primary failure factors. Marginal integrity and the absence of bioactivity at the tooth-restoration junction contribute to recurrent caries development. Consequently, this dissertation endeavors to introduce a novel bioactive low-shrinkage-stress nanocomposite, featuring dimethylaminododecyl methacrylate (DMADDM) as an antibacterial agent, as well as remineralization nanoparticles of calcium fluoride (nCaF2) and nanoparticles of amorphous calcium phosphate (NACP), with the potential of increase the longevity of dental restoration and protect tooth structure. All novel formulations of low-shrinkage-stress composite were subjected to a series of mechanical, antibacterial, cytocompatibility, and ion release assessments. First, we investigated the optimum concentration of DMADDM that can be incorporated with a low-shrinkage-stress composite without compromising mechanical properties. We found that incorporation of up to 5% DMADDM into a low-shrinkage stress composite efficiently inhibited Streptococcus mutans (S. mutans) biofilm commonly associated with secondary caries. This potent antibacterial effect is achieved while maintaining excellent mechanical properties and minimizing polymerization shrinkage stress, potentially improving the long-term success of dental restorations. Next, we investigated the antibacterial and cytocompatibility of the incorporation of 3% DMADDM with 20% nCaF2 or 20% NCAP into a low-shrinkage-stress nanocomposite. We found that incorporating DMADDM with either nCaF2 or NACP into a low-shrinkage-stress nanocomposite provides a potent antibacterial effect against S. mutans biofilm while maintaining excellent mechanical properties. In addition, the novel formulations demonstrated excellent biocompatibility against human gingival fibroblasts and dental pulp stem cells. Lastly, we investigated the ions release and antibacterial properties against a salivary biofilm for our innovative formulations. The innovative mixture of DMADDM, NACP, and nCaF2 demonstrated strong antibiofilm effects on salivary biofilm, while concomitantly releasing a significant amount of remineralizing ions. This nanocomposite is a promising dental material with antibiofilm and remineralization capacities, with the potential to reduce polymerization-related microleakage and recurrent caries.
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The quality of information on oral hygiene instructions for orthodontic patients in TikTok videosObjective: The study aimed to assess the reliability, content, quality, and overall usefulness of orthodontic oral hygiene instructions in TikTok videos. Methods: The final videos were evaluated for content, reliability, quality, and usefulness by using a content domain checklist, DISCERN questionnaire, and Global Quality Scale (GQS). Descriptive video characteristics were also recorded. Results: Dental professionals uploaded 70.00% of the TikTok videos, with orthodontists responsible for 39%. The videos had average scores of 2.19 for DISCERN, 3.96 for content, 2.14 for GQS, and 6.10 for usefulness. Video length was significantly associated with content scores (r = 0.3553, P = 0.0003), usefulness (r=0.3553, P = 0.0003), and quality (GQS) (r=0.2620, P=0.0085). Conclusion: Most TikTok videos on orthodontic oral hygiene were uploaded by dental professionals. Reliability, content, and quality of the videos were all poor. Videos were considered slightly useful. Longer videos were significantly correlated with higher content, higher quality, and increased usefulness.
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Perception of lip attractiveness: a survey of orthodontists, general dentists, and laypersonsWe aim to investigate the proposed standards of ideal lip proportions and compare those standards to what different people view as most attractive. A 16-question survey was distributed via Qualtrics to orthodontists, general dentists, and laypersons asking demographics as well as opinion-based questions regarding a series of facial photographs. Photographs were digitally altered using Adobe Photoshop to produce different dimensions of the lips from both profile and frontal views. Participants were asked to rate the perceived attractiveness of the lips shown. Regardless of occupation, individuals preferred the appearance of slightly protrusive or thicker lips. Retrusive and thin lip varieties had the lowest median attractiveness scores. Average values for lip projection and thickness were not found to be mutually agreed upon across occupation types (p<0.05) and average lip thickness was not mutually agreed upon between age groups of orthodontists (p=0.004). Based on the results of this study, care should be taken not to produce retrusive or thin lips during orthodontic treatment. Acceptance of a slightly thick or protrusive lip profile may be a more esthetic or well-accepted patient outcome.
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Three-Dimensional Assessment of Virtual Clear Aligner Attachment Removal: A Prospective Clinical StudyVirtual attachment removal (VAR) is a process used in digital dentistry to prefabricate retainers by removing attachments from a digital scan before the removal of clear aligner attachments. This study aims to evaluate the accuracy of VAR in the maxillary arch. 110 teeth were analyzed from a sample of 54 maxillary scans from 25 subjects. Models with attachments were virtually debonded using Meshmixer® and superimposed over the control group in MeshLab. Vector Analysis Module was used to calculate 3D distances on the buccal surfaces between the superimposed models. The VAR protocol showed no statistical differences in the root mean square between different tooth segments with an overall tendency for inadequate attachment removal. No difference between the groups were found when regarding the number of attachments was used as a main factor. The VAR technique is precise enough for the fabrication of retainers from printed dental models in a clinical setting.
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Effect of Polydopamine-RGD Peptide Coating on the Adhesion of Cultured Fibroblasts on Polymethylmethacrylate Provisional Custom Abutment MaterialsCellular attachment properties of the temporary and prosthetic abutment is one of the important factors for creating optimal peri-implant soft tissue around the implant. Surface modifications appear to play an important role in promoting early healing of the soft tissue around the dental implant, affecting primarily the epithelium, fibroblast, and osteoblast cell behavior. Another strategy to better manage peri-implant and abutment soft tissue integration is to coat the surface with bioactive agents to enhance biocompatibility. Among the most commonly utilized are proteins and peptides. The proposed in-vitro study will provide better insights of surface characteristics for implant-abutment interface by application of the peptide RGD for optimized attachment of peri-implant soft tissue cells. The hypothesis is that application of polydopamine and the peptide RGD on the implant-abutment surface can improve fibroblast early attachment, migration and proliferation, thereby advancing early wound healing and establishing peri-implant soft tissue attachment.
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The Etiology of Peri-implantitis: Microbiological Profile Within and Around Dental Implants and the Associated Human Immune ResponseObjectives: To characterize the microbiome composition within and around dental implants of peri-implantitis subjects and within and around healthy implants using 16S rRNA gene sequencing, and to profile salivary inflammatory mediators associated with peri-implantitis compared to healthy controls from the same subjects. Methods: A total of 24 subjects (peri-implantitis n=14, healthy n=10) were enrolled in the study. From the 24 subjects, 24 endosseous implants from affected (peri-implantitis) and 14 healthy controls were included in this cross-sectional study. Samples for microbiological analysis were obtained from the internal surfaces of dental implants and peri-implant sulcus using sterile paper points. DNA was extracted and 16S rRNA gene was amplified using universal primers targeting the V3-V4 regions. Amplicons were sequenced using Illumina MiSeq platform. Alpha and beta diversity, core microbiome, and taxa differential abundance were assessed. Saliva was collected from the same subjects for immunology-based assays. Salivary inflammatory mediators in peri-implantitis and healthy implant subjects were profiled using antibody arrays. Results: A significant increase in microbial diversity was observed in the internal implant surface of healthy implants compared with the internal surfaces of peri-implantitis (Shannon P= 0.02), and no significant differences in microbial diversity between healthy implants sulci and peri-implantitis pockets (Shannon P= 0.82). Bacterial community structure was significantly different within implant in both healthy and peri-implantitis groups (P= 0.012) but not significantly different around implants in both healthy and peri-implantitis (P= 0.18). Enterococci is the predominant bacteria within peri-implantitis (LD >2.0, P< 0.05). Abundant species in peri-implantitis were C. leadbetteri, T. maltophilum, Peptostreptococcus, Neisseria, P. gingivalis, and P. endodontali, L. lactis and F. alocis (P < 0.05). Gram-positive bacteria such as S. salivaris, P. melaninogenica, L. wadei, and Actinomyces spp were more abundant in the peri-implant healthy sulcus. Around 48% of detected bacteria were cultivable in general media. In addition, out of 105 analytes examined in saliva, we found that 29 mediators were upregulated in subjects with peri-implantitis (P < 0.001). Conclusions: Our results indicate that microbial colonization of the internal implant surface may act as a major contributor to the etiology of peri-implant disease. Multiple inflammatory mediators were significantly elevated in the saliva of peri-implantitis patients compared to healthy implant patients.
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Effect of Contact Type on Caries Experience in Primary DentitionPurpose: The aim is to evaluate effect of contact type and other caries risk factors (diet, plaque, and fluoride) on caries experience in primary dentation. Secondly, to assess prevalence of OXIS contacts among 3-10 years old children enrolled in the study. Methods: Clinical examination was completed on healthy children 3 to 10 years of age. Contact type of primary molars was recorded based on OXIS classification. Information on other caries risk factors were collected (plaque, fluoride, and diet habits). The outcomes assessed included clinical caries (presence/absence), decayed, missing, and filled primary teeth (dmft), decayed teeth (dt), and decayed surfaces (ds). Results: A total of 277 contacts were examined in 107 children ( 51 females and 56 males). Moderate plaque was found to be associated with dmft and dt for contacts S, I, and X. High diet frequency was associated with high dmft and dt scores for contacts S, I, and X. Contact type I showed significant association with dmft compared to other contacts in multivariable analysis. Conclusion: Both high diet frequency and moderate plaque index were linked to higher caries experience in children with contact types S,I, and X. Contact type I found to be associated with higher dmft scores compared to other contacts (X and S).
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Comparison of Shear-bond Strength of Orthodontic Brackets on Enamel with use of Pro Seal with Assure PlusTitle of Thesis: Comparison of Shear-bond Strength of Orthodontic Brackets on Enamel with use of Pro Seal with Assure Plus David Greene, Master of Biomedical Sciences, 2023 Thesis directed by: Dr. Dina Sanchez, Director of Predoctoral Orthodontics, Clinical Assistant Professor, Department of Orthodontics and Pediatric Dentistry We aim to investigate the shear bond strength of orthodontic brackets bonded with Assure Plus alone and in combination with Pro Seal, following the manufacturer's recommended bonding protocol. Forty-two (42) extracted premolar human teeth were randomly assigned to two bonding groups, the control group (Assure Plus) and the test group (Assure Plus and Pro Seal). After bonding, the teeth were stored at 37°C for 24 hours. Next, the shear bond strength test was completed. The results of the Mann- Whitney test showed there was not a statistical difference of shear bond strength between the two groups for the variables, Peak Load and Shear Bond Strength. The use of Pro Seal with Assure Plus as a preventive measure for white spot lesions during orthodontic treatment does not negatively impact the shear bond strength of orthodontic brackets during treatment.