AbstractINTERLEUKIN-6 LEVELS IN GENERALIZED AND LOCALIZED AGGRESSIVE PERIODONTITIS PATIENTSBy Bindu Reddy, D.D.S.A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at the Virginia Commonwealth UniversityVirginia Commonwealth University, 2004Major Director: Joseph V. Califano, D.D.S., Ph.D.Associate Professor, Department of Periodontics Periodontitis is an inflammatory disease involving the supporting structures of the dentition. Many studies have shown that there is a relationship between periodontal disease, the presence of pro-inflammatory cytokines, and systemic disease such as cardiovascular disease and diabetes mellitus. The purpose of this study was to measure serum Interleukin-6 levels in generalized and localized aggressive periodontitis and non-periodontitis patients and look for relationships with measures of disease severity. We also examined variables known to have a relationship with IL-6. A total of 172 subjects, comprising three periodontal subgroups, non-periodontitis (NP=61), generalized aggressive periodontitis (GAP=77), and localized aggressive periodontitis (LAP= 34), had serum samples evaluated for IL-6 levels using a highly sensitive ELISA test. The IL-6 levels were compared with clinical and demographic data including age, race, gender, number of teeth, probing depth, attachment loss, bleeding index, plaque index, gingival index, cotinine levels, smoking status, and CRP levels. Using multiple regression analysis, smoking status (p=0.0015) was the only variable found to have a significant relationship with IL-6 levels for all three groups.

Clinicians have described the success rates of dental implants. The use of implants is projected to increase in the future. With a 5-10% failure rate, it is unclear the exact factors that are associated with implant failures. To improve upon these success rates, it is critical to understand parameters associated with implant failure including: periodontitis, peri-implantitis, systemic diseases, site preparation, dental history of the implant site, bone quality, materials, occlusion, and treatment timelines. While bone quality is associated with failure, objective measures to assess bone quality and characteristics are scarce. Therefore, the aim of this study is to determine whether possible comorbidities, associated dental parameters, and measurable bone quality are possible predictors of implant failure. In this study, we utilized the electronic health record system axiUm® to retrospectively investigate non-failed (NF) and failed (F) dental implants from a patient cohort with 149 implants placed between 2012-2015 at Virginia Commonwealth University School of Dentistry. A chart review was conducted extracting information on age, gender, systemic diseases, smoking, occlusal trauma, parafunction, bone grafting history, treatment timelines, implant site/type/placement protocol, infection, torque at placement, bone quality and microarchitecture assessed by the novel, innovative technology: trabecular bone score (TBS). A total of 149 implants, 46 failures and 105 non-failed controls, were selected based on similar implant sites. Preliminary data obtained from analysis suggests that average time from implant placement to failure was 6.6 months (0.55 years). Parafunction habit (p=0.0202) and increased number of implants (p=0.0478) were found to be associated with increased implant failure.

O biofilme é um dos fatores primários para o desenvolvimento da gengivite, periodontite e outras alterações na saúde gengival do paciente. O tratamento ortodôntico é um fator predisponente para adesão de microrganismos deixando o paciente susceptível ao maior acúmulo de biofilme e, consequentemente, às doenças periodontais. Assim, o objetivo do presente estudo foi avaliar as alterações clínicas, microbiológicas e imunológicas no paciente em tratamento ortodôntico corretivo e testar as hipóteses nulas: 1 - não há diferença nos parâmetros clínicos, microbiológicos e imunológicos antes e durante o tratamento ortodôntico, 2 não há correlação entre os índices clínicos e imunológicos. Em 28 pacientes com necessidade de tratamento ortodôntico corretivo foram avaliados parâmetros clínicos como índice de Placa (IP), índice de Sangramento (IS), largura de gengiva queratinizada (LGQ); parâmetros microbiológicos por meio da contagem de 40 espécies subgengivais em amostras de biofilme (Checkerboard DNA-DNA Hybridization) e avaliação imunológica por meio da expressão dos níveis de Interleucina-1 β (IL-1β ), metaloproteínase da matriz-8 (MMP-8) e Fator de Necrose Tumoral (TNF-α) no Fluído Crevicular Gengival (FCG) (Luminex). Foram realizadas coletas em 3 momentos: T0 = antes da colocação do aparelho; T1 = 6 meses após e T2= 12 meses após o início do tratamento. Para as análises clínicas e microbiológicas foram aplicados teste de Friedman e Wilcoxon com correção de Bonferroni e para a análise imunológica, Análise de variância para medidas repetidas. Não foi observada diferença estatisticamente significante para a LGQ. IP apresentou aumento, sendo estatisticamente significante em T1 (70,58±28,56) e T2 (83,23±12,30) quando comparados ao T0 (24,44±11,56). O IS apresentou aumento estatisticamente significante em T1 (7,97±5,04) e diminuição em T2 (6,20±4,09), demonstrando valores sem diferença estatisticamente significante a T0 (4,54±4,98). Na análise microbiológica, dentre os seis complexos analisados, apenas o complexo vermelho apresentou frequência significativamente maior (p=0,001) em T2. Não houve diferença estatisticamente significante nos valores dos níveis das citocinas avaliadas, entre todos os tempos (p>0,05), porém em T2 houve correlação positiva moderada entre IS e IL-1β (r=0,49 p=0,01) e TNF-α (r=0,39 e p=0,05). As hipóteses nulas foram rejeitadas. O tratamento ortodôntico corretivo causou alterações periodontais clínicas com relação ao acúmulo de biofilme e sangramento gengival, alterações de bactérias periodontopatogênicas, além de gengivite após 6 meses de tratamento / The biofilm is one of the primary factors for the gingivitis and periodontitis development and changes in periodontal health. Orthodontic treatment is a predisposing factor for microorganisms adhesion leaving the patient susceptible to greater biofilm accumulation and, consequently, to periodontal diseases. Therefore, the study aimed to analyze clinical, microbiological and immunological parameters in patients in orthodontic treatment. The null hypothesis tested were: 1 - there is no difference in clinical, microbiologica and immunological parameters before and during orthodontic treatment; 2 there is no correlation between clinical and immunological parameters. In twenty-eight patients with corrective orthodontic treatment were evaluated clinical parameters, such as Plaque index (PI), Bleeding on Probing (BOP) and width of keratinized gingiva; microbiological parameters with counting of 40 subgingival species with Checkerboard DNA-DNA hybridization and immunological evaluation of cytokines levels IL-1β , MMP-8 and Tumor Necrosis Factor (TNF-α) in Gingival Crevicular Fluid (GCF). Samples were collected in three times: T0 = before orthodontic treatment; T1 = 6 months after and T2 = 12 months after starting orthodontic treatment. Data from clinical and microbiological evaluation were statistically analyzed with Friedman and Wilcoxon tests with Bonferroni correction and for the immunological analysis, Analysis of variance for repeated measures were applied. No significant difference was found for the width of keratinized gingiva. PI presented an increase, being statistically significant at T1 (70.58±28.56) and T2 (83.23±12.30) when compared with T0 (24.44±11.56). The BOP showed a statistically significant increase at T1 (7.97±5.04), however, at T2 (6.20±4.09) the values decrease with no statistically significant difference with T0 (4.54±4.98). In the microbiological analysis, the red complex showed significantly greater frequency (p=0.01) at T2. There was no statistically significant difference in the cytokine levels between the times, but there was a positive moderate correlation between BOP and IL-1β (r=0.49 p=0.01) and TNF-α (r=0.39 e p=0.05). The null hypothesis were rejected. Corrective orthodontic treatment caused clinical periodontal changes regarding biofilm accumulation and gingival bleeding, alterations of periodontopathogens, besides gingivitis after 6 months of treatment

Purpose: To determine the characteristics influencing periodontal practices in Virginia and report on the anticipated changes in practice. Methods: A REDCap survey was emailed to Virginia based American Academy of Periodontology (AAP) members assessing personal and practice demographics, trends in dental treatment and practice models, and how periodontists will adjust to account for these trends. Results: The response rate was 31% (n=46). Respondents report greater referrals from more experienced general practitioners (GPs). Student debt was associated with age. Respondents ranked biologic advances, treatment of peri-implantitis, digital dentistry, development of corporate and group practice models, and GPs incorporating more periodontal services in their practices as most likely to impact periodontal practices. The most reported periodontal practice adjustments included expansion of existing services, increasing the number of periodontists in the practice, and joining with other specialists or GPs to create group practices. Conclusions: Periodontists perceive the need to expand services, increase number of providers in their practices or create group practice models as future practice adjustments.

Periodontitis is an inflammatory disease of the oral cavity induced by anaerobic bacteria, that remains to be the primary cause of tooth loss in adults worldwide. Finding an anti-microbial therapeutic to selectively target periodontal pathogens has proven to be difficult, and current treatment modalities only provide a transient benefit. Amixicile is a non-toxic, readily bioavailable novel antimicrobial that targets strict anaerobes through inhibition of the activity of Pyruvate Ferredoxin Oxidoreductase (PFOR), a major enzyme mediating oxidative decarboxylation of pyruvate, a critical step in metabolism. Our study aimed to evaluate the efficacy of amixicile in inhibiting the growth of bacteria harvested from the complex sub-gingival biofilm of patients with chronic periodontitis. We hypothesize that amixicile will selectively inhibit pathogenic anaerobic bacteria collected from patients, with the same efficacy as metronidazole, the current accepted treatment modality. Plaque samples were harvested from patients with severe chronic periodontitis and cultured under anaerobic conditions. The microbiomes were grown in the presence of amixicile and metronidazole and the growth was compared to that of bacteria grown in the absence of the antimicrobials. Following 24 hour incubation, bacterial DNA was isolated and bacterial quantity was evaluated by quantitative PCR (qPCR) using primers specific for 12 bacterial species: P. gingivalis (Pg), P. intermedia (Pi), F.nucleatum (Fn), S.gordonii (Sg), S. anginosus (Sa), V. atypical (Va), L. acidophilus (La), A.actinomycetemcomitans (Aa), T.denticola (Td), S.mutans (Sm), S.sanguis (Ss), and 16s. Individual qPCR runs were combined to represent an overall average of CT value differences. Amixicile treatment groups exhibited statistical significant reductions (PP. intermedia, F. nucleatum and Veillonella atypical. When comparing amixicile to metronidazole, amixicile performed with similar efficacy with the largest effect seen for PFOR bacteria. Our conclusion supports amixicile as a potent inhibitor of anaerobic bacteria, and could be a potential new therapeutic antimicrobial in the treatment of periodontal disease

Background: Exosomes have great potential in regenerative medicine through the transfer of their bioactive cargos, such as RNA. tRF RNA and tiRNA are tRNAderived non-coding RNA. Here, we sought to identify the tRF/tiRNA profile in human mesenchymal stem cell (hMSC) exosomes. Methods: Bone marrow hMSCs were cultured with/without osteogenic differentiation medium and exosomes were harvested. RNA was extracted from: 1) control cells (Cell-NT); 2) control exosomes (EXO-NT); 3) differentiated cells (Cell-OM); 4) exosomes produced by differentiated cells (EXO-OM). RNA was sequenced to profile the small RNA with a focus on tRF/tiRNA. Results: tRF/tiRNA was highly enriched in hMSC exosomes. Less diversity was seen in the tRF/tiRNA profile in exosomes than that in parent cells. Selective tRF/tiRNA were packed into MSC exosomes and their profile is dependent on the cell maturation status. Conclusions: Our results suggest that tRF/tiRNA may play a role in mediating the function of exosomes in tissue regeneration.

The purpose of this study was to investigate if the addition of biologic materials and/or oral steroids would affect horizontal bone gain, or the bone density of the grafted bone in horizontal alveolar ridge augmentations. A retrospective chart review was completed to assess the clinical and radiographic outcomes of 53 ridge augmentation patients. An average bone gain of 3.6mm of width was found in our study based on radiographic analysis. There were no statistically significant differences found in the linear bone gain with the addition of biologic materials and steroids. A marginally statistically significant difference was found in the bone density when biologics were added (p-value=0.0653). No statistically significant difference found in the bone density with the addition of oral steroids. The use of tenting screws and resorbable occlusive membranes and a combination of allograft and xenograft bone materials provides significant clinical and radiographic dimensional changes in alveolar ridge width.

The aim of this study was to describe the prevalence of gingivitis, periodontitis and dental caries in individuals with type 2 – diabetes. The study was conducted in a form of a general literature review with the restricted to the following conditions: human studies, English, and articles published between 2007 - 2012. Articles lacking a control group were excluded. The data were collected through searches of the medical database PubMed. A compilation of 11 scientific articles was examined. In individuals with diabetes mellitus type 2, the presence of gingivitis was identified in 3 articles, periodontitis in 10, and dental caries in 3 articles. The 3 articles that showed presence of gingivitis demonstrated that individuals with type 2 – diabetes had a higher prevalence of gingivitis compared to non-diabetic individuals. A higher prevalence of periodontitis in individuals with type 2 – diabetes mellitus was found in 10/10 publications. Theses studies demonstrated in individuals with type 2 – a significantly higher incidence of deep pocket depths, attachment loss, recession defects and with higher plaque and gingival index scores. The three articles that showed the presence of dental caries also demonstrated a higher prevalence of dental caries in individuals with type 2 – diabetes mellitus.  The articles included in the literature study showed statistically significant higher prevalence of gingivitis, periodontitis, and dental caries in individuals with type 2 – diabetes mellitus than in individuals without a diagnosis of diabetes. Keywords: Type 2 – Diabetes, Gingivitis, Periodontitis and Dental Caries

Thesis (Ph.D.)--Boston University, Henry M. Goldman School of Dental Medicine. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Porphyromonas gingivalis , a Gram-negative anaerobic pathogen of periodontal diseases, requires iron in the form of heme (a term used to denote either the ferrous or ferric form of iron protoporphyrin IX) for growth. P. gingivalis is capable of utilizing a broad range of heme-containing compounds such as hemoglobin, hemoglobin-bound haptoglobin, hemin-bound hemopexin and hemin-saturated serum. Heme and hemoglobin utilization in P. gingivalis requires the participation of an outer membrane protein HmuR (heme utilization receptor), as well as cysteine proteinase gingipains (Lysine-specific gingipain Kgp and Arginine specific gingipains Rgps). However, the specific mechanisms utilized for heme acquisition are poorly understood. In this study, the role of HmuR in heme utilization was characterized in both E. coli and P. gingivalis . Molecular interaction between HmuR and hemin/hemoproteins was also characterized by construction and analysis of HmuR site-directed mutants. Our results support the direct role of HmuR in heme utilization. Hemoprotein utilization in P. gingivalis requires the participation of HmuR conserved residues. The HmuR residues 95 and 434, as well as the NPDL motif, seem to be involved in whole cell binding of hemoproteins; while the YRAP motif does not. All these residues seem essential for serum hemoprotein utilization. Analyses of HmuR by homology modeling provided a structural basis for functional analysis and supported the results from mutagenesis studies. In addition, expression of the hmuR, kgp and rgpA genes in response to different heme sources was also examined. We found that expression of the hmuR gene was negatively regulated by heme, while expression of the kgp and rgpA genes seemed to be regulated by growth phase. These different regulatory mechanisms, as well as the coordinate expression between HmuR and gingipains, indicate a complementary regulation mechanism for optimal heme utilization in P. gingivalis. / 2031-01-01

Thesis (M.A.)--Boston University, 2008. / The use of bisphosphonate has become more widespread for the treatment of bone metastasis, multiple myeloma, osteoporosis, Paget's disease and other bone malignancies. Osteonecrosis of the jaw (ONJ) has been recently recognized as a possible complication of the use of bisphosphonate therapy. This study includes a review of the literature on the mechanism of action of bisphosphonate and its potential association to the development of osteonecrosis of the jaw. The inhibitory effects of bisphosphonates on osteoclasts and its antiangiogenic properties have been examined as possible mechanisms to induce osteonecrosis of the jaw. The incidence of ONJ in osteoporosis patients receiving bisphosphonate treatment is <1 in 100,000, and in between 1% and 10% in patients with malignancy (Hess et al., 2008). The results of this study suggest a higher incidence of osteonecrosis of the jaw in patients under long term use of nitrogen containing bisphosphonate. The incidence of bisphosphonate associated ONJ in the first 4 to 12 months of therapy was of 1.5% and it increased to 7.7% after 37 to 48 months [Bamias] Additional risk factors include dental extractions, invasive dental procedures and trauma. It is not yet clear, however, if other drugs that affect bone turnover may induce similar complications. This study suggests an association of bisphosphonates to the development of osteonecrosis of the jaw. There is no evidence that bisphosphonates cause osteonecrosis of the jaw. An evaluation of the published data indicates that more research is necessary to understand the relationship of bisphosphonates and osteonecrosis of the jaw.