Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Nonsurgical root canal therapy procedures aim to reduce the total microbial load within an infected root canal system through chemomechanical debridement of the root canal system via instrumentation in conjunction with an antibacterial irrigating solution. The most commonly used irrigant is sodium hypochlorite, often at concentrations toxic to human cells. Electromagnetic wave irradiation is a novel method of disinfection that has been shown to be bactericidal against planktonic microorganisms in solution, but its efficacy against an established biofilm is unknown. Pilot studies have demonstrated a synergistic killing effect with sodium hypochlorite through a process termed electromagnetic stimulation (EMS). If confirmed, lower concentrations of the current gold standard of 6.0-percent sodium hypochlorite could be used to irrigate infected root canals during endodontic treatment, resulting in less toxicity to human cells. There are also regenerative implications as EMS could be used to disinfect the root canals of immature teeth using 1.5-percent sodium hypochlorite, as recommended by the American Association of Endodontists. Objectives: The purpose of this in-vitro study was to evaluate the anti-biofilm effect of EMS against an established biofilm of Enterococcus faecalis. Materials and Methods: Single rooted teeth were cut to a standardized length (12 mm) and instrumented with a 45.05 Wave One Gold reciprocating file. Specimens were sterilized and inoculated with E. faecalis, which grew for two weeks to form an established biofilm. There were five treatment groups: 1) 6.0-percent sodium hypochlorite; 2) 1.5-percent sodium hypochlorite; 3) 1.5-percent sodium hypochlorite with EMS; 4) 0.9-percent saline with EMS and 5) 0.9-percent saline. Samples were collected, plated, and incubated for two days. The number of CFUs/mL was determined and converted to log10. The effect of treatment group on bacterial counts was made using Wilcoxon Rank Sums Test. One sample per group was scored and split for confocal imaging. Null Hypothesis: Teeth treated with EMS in combination with 1.5-percent sodium hypochlorite or 0.9-percent saline will not demonstrate a significant anti-biofilm effect in comparison to those treated with 6.0-percent sodium hypochlorite alone. Results: 0.9-percent saline and 0.9-percent saline with EMS were significantly higher than 6.0-percent NaOCl, 1.5-percent NaOCl, and 1.5-percent NaOCl with EMS. 0.9-percent saline was significantly higher than 0.9-percent saline with EMS. The three groups that included treatment with NaOCl were not significantly different from each other. Confocal imaging confirmed the CFU findings. Conclusion: Because there was no growth in any of the NaOCl groups, the null hypothesis cannot be rejected. However, there was an antibiofilm effect when comparing the two saline groups, demonstrating that EMS has an antibiofilm effect. Future studies should focus on determining what concentration of NaOCl is most effective in combination with EMS.

published_or_final_version / abstract / Dentistry / Master / Master of Dental Surgery

Foi avaliada a eficácia da terapia fotodinâmica, empregando o fotossensibilizante azuleno e laser de baixa intensidade, associado ao preparo químico-cirúrgico convencional (hipoclorito de sódio a 0,5% e endo-ptc) de canais radiculares de dentes de cães. Para isso, foram utilizados 20 cães provenientes do Hospital Veterinário da FMVZ/USP, cada qual apresentando um dente unirradicular com morte e contaminação pulpar e, radiograficamente, lesão de rearefação óssea periapical. Os cães foram divididos em dois grupos de dez animais. O primeiro grupo foi submetido ao tratamento endodôntico, iniciando a anti-sepsia através do preparo químico-cirúrgico e, posteriormente a terapia fotodinâmica. O segundo grupo foi submetido ao tratamento endodôntico, iniciando a anti-sepsia pela terapia fotodinâmica e, posteriormente foi realizado o preparo químico-cirúrgico. Os resultados mostraram que a terapia fotodinâmica intracanal tem eficácia semelhante à anti-sepsia do preparo químico-cirúrgico. A ordem de emprego do preparo químico-cirúrgico e terapia fotodinâmica não influencia no resultado de anti-sepsia. O emprego de azuleno irradiado por laser de baixa potência tem grande eficácia sobre espécies de enterococos no interior dos condutos, e é eficaz na diminuição do número de bactérias totais intraradiculares. Os resultados sugerem que há uma tendência em afirmar que o emprego de azuleno irradiado por laser possa diminuir a quantidade de espécies de leveduras. / The photodynamic therapy efficacy was evaluated, using the photosensitizer azulene and low intensity laser, associated to the conventional root canal therapy (0,5% sodium hipoclorite and endo-ptc endodontic paste) in teeth of dogs. Twenty dogs from the Veterinary Hospital of the FMVZ/USP were used, each one presenting one uniradicular tooth with death and pulp contamination and, radiographic injury of periapical bone reabsorption. These dogs were divided in two groups of ten animals. The first group was submitted to the endodontic treatment, starting the anti-sepsis through the conventional root canal therapy and, subsequently the photodynamic therapy. The second group was submitted to the endodontic treatment, starting the anti-sepsis by photodynamic therapy and, subsequently the conventional root canal therapy. The results showed that intracanal photodynamic therapy has similar efficacy compared to the anti-sepsis of the conventional root canal therapy. The order of application of the conventional root canal therapy and photodynamic therapy does not interfere in the result of anti-sepsis. The use of irradiated azulene by low intensity laser has strong efficacy over species of enterococus inside the ducts. The use of irradiated azulene by low intensity laser is efficient in the reduction of total numbers of intracanal bacterias. The results suggest that there is a tendency to affirm that the use of irradiated azulene by low intensity laser can reduce the quantity of species of yeast.

Over 15 million root canal treatments (RCT) are performed yearly in the United States to treat deep caries and dental pulp infection. This procedure however, removes both the diseased and healthy pulp, leading to tooth devitalization. Furthermore, RCTs are associated with a high incidence of re-infection and dentin fracture, reduced sensitivity and eventual tooth loss. Thus there is an unmet clinical need for alternative endodontic therapies that can preserve tooth vitality and ensure long term dental health. The strategy of vital endodontic therapy explored in this thesis centers on the design of a bioactive scaffold that guides host cell homing while providing antibiotic release, in effect harnessing the intrinsic repair potential of the native pulp while simultaneously eliminating residual bacteria that can cause recurrent infection. Specifically, a bioactive polyethylene glycol fibrinogen (PEG-fibrinogen) hydrogel is optimized to support host cell infiltration, maintain dental pulp cell phenotype, and enable pulp regeneration. Ciprofloxacin, a clinically relevant antibiotic for RCT, is incorporated into PEG-fibrinogen to prevent infection. The scaffold and culturing parameters optimized in vitro using either explant or a tooth slice model includes fibrinogen, poly(ethylene glycol) diacrylate (PEGDA) and photoinitiator concentration, as well as cell source and density. In addition, dose-dependent antibiotic effects on both anaerobic bacteria isolated from deep caries and healthy pulp cells are evaluated. The collective findings of this thesis demonstrate that a cell-instructive hydrogel comprised of a fibrinogen backbone and cross-linked with difunctional poly(ethylene glycol) side chains supports pulp cell viability, phenotypic morphology, and host cell migration. Furthermore, increasing pulp cell density promotes cell biosynthesis and a higher fibrinogen concentration is found to enhance collagen deposition. Photoinitiator and PEGDA concentrations have been optimized to enhance hydrogel mechanical properties and gel degradation, while supporting pulp cell phenotype. An optimal antibiotic dosage in the hydrogel has been identified that significantly reduces bacteria count from infected dental pulp without harmful side effects on dental pulp cell phenotype and host cell migration. In summary, this thesis focuses on the design of a bioactive hydrogel-based scaffold with antibiotic release that can induce dental pulp regeneration without the addition of cells and stimuli such as growth factors and minimize post-therapy infection. The innovative scaffold design strategy presented here lays the foundation for the development of vital endodontic therapy that harnesses pulp self-repair and sustains long-term tooth function.

Orientador: Mário Tanomaru Filho / Banca: José Milton Carlos Kuga / Banca: Marco Antonio Hungaro Duarte / Resumo: Modificações têm sido propostas ao MTA e cimento Portland para a obtenção de um cimento obturador de canal radicular. Um material experimental à base de MTA (CE-MTA) é avaliado neste estudo para emprego como cimento endodôntico, contendo cimento Portland, radiopacificador, aditivos e veículo. Assim, o objetivo deste estudo foi avaliar o cimento experimental, usando como parâmetros comparativos o cimento AHPlus (AHP), MTA-Angelus (MTA) e cimento Portland (CP). Foram realizados testes de tempo de presa; resistência à compressão; escoamento; radiopacidade; alteração do pH e liberação de íons cálcio. Todas as metodologias foram definidas usando como referência normas ISO e a literatura científica recente da área endodôntica. O teste de escoamento seguiu a metodologia proposta pela norma ISO, com a medição do diâmetro dos discos de cimento, assim como da área por meio de um programa de imagens. O tempo de presa foi avaliado pela norma da ADA/ASTM, verificando os períodos de tempo necessários para que as agulhas indentadoras (100g e 2mm de diâmetro na ponta; e 456g e 1 mm de diâmetro na ponta) não marcassem a superfície dos discos de cimento, fornecendo resultados para a presa inicial e final. No teste de radiopacidade foi feita uma comparação da radiopacidade de discos de cimento de 10mm de diâmetro e 1 mm de espessura, com uma escala de alumínio padronizada. A alteração de pH do foi avaliada com um pHmetro e a liberação de cálcio com um espectrofotômetro de absorção atômica. Para ambos os ensaios tubos preenchidos com o cimento foram imersos em frascos contendo água destilada. Os tubos foram passados para um novo frasco contendo mais água destilada nos períodos de tempo de 3, 6, 12, 24 e 48 horas, assim como 7, 14 e 28 dias. O líquido remanescente nos frascos foi avaliado para obter os resultados deste ensaio. Na resistência à compressão... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Modifications of MTA and Portland cement has been proposed to obtain an root canal sealer. This study evaluates an experimental MTA based root canal sealer (CE-MTA) which contains Portland cement, radiopacifier, addictives and a vehicle. The aim of this study was to evaluate the experimental endodontic sealer, using white Portland cement (CP), MTAAngelus(MTA) and AH Plus (AHP) as control groups. The tests realized were: setting time, radipacity, compressive strength, pH alterations, calcium release and flow. The flow test followed the ISO 6876 norms, and the the sealer discs' area was measured with a paquimeter and using an area measurement software. The setting time was measured based on the ADA/ASTM Norm, allowing initial and final setting time measurements. Radiopacity was measured using an aluminum scale as reference and sealer discs with 10 mm in diameter by 1 mm thick. The pH was measured using a pHmeter and the calcium release using an atomic absorption spectrophotometer. For compressive strength test the ISO 9917 methodology was used, testing specimens at 24 hours and 21 days. All the data was submitted to statistical analysis, a normality test, and after the data normality check, an ANOVA and a Tukey test using 5% significance were applyed. Results: The results showed that CE-MTA has flow similar to AH Plus and superior to the minimum required by the ISO standard. The setting time was faster than AH Plus and slower than MTA and Portland cement. The compressive strength was lower for the experimental sealer at 24 hours time compared with all the tested materials, and similar for the experimental sealer and MTA at 21 days. The experimental sealer had a superior calcium release in all period of time, and higher pH values until 48 hours period, being similar to MTA and Portland cement on posterior time periods. The experimental sealer radiopacity was lower... (Complete abstract click electronic access below) / Mestre

Orientador: Frederico Canato Martinho / Banca: Aletéia Massula de Melo Fernandes / Banca: Ana Paula Martins Gomes / Resumo: Sabe-se que as endotoxinas provenientes das bactérias grã-negativas desempenham um importante papel nas infecções endodônticas se relacionando à sinais e sintomas clínicos/radiográficos. Sendo assim, a redução ou eliminação de endotoxinas é fundamental para a resolução da inflamação periapical. Os objetivos do presente estudo foram: Artigo 1 - realizar uma revisão sistemática com metanálise com o intuito de avaliar a relação entre níveis de endotoxinas e a presença de sinais e sintomas clínicos, bem como de sinais radiográficos em pacientes com infecção endodôntica primária; Artigo 2 - fazer um ensaio clínico randomizado para avaliarmos estratégias clínicas para otimizar a eliminação microbianana e de lipopolissacarídeos (LPS) utilizando a Terapia Fotodinâmica (PDT) como tratamento suplementar ao PQM nas modalidades de terapia endodôntica em única e múltiplas sessões. Métodos: Artigo 1 - para a revisão sistemática uma busca eletrônica foi realizada por dois autores, no idioma inglês, nas bases de dados Medline/PubMed, Embase, Cochrane Library, Scielo, Science Direct, Web of Knowledge e Scopus. Após seleção dos artigos foi realizado uma metanálise com análises de sinais e sintomas clínicos/radiográficos. Artigo 2 - Selecionou-se 24 casos de dentes com infecção endodôntica primária que foram aleatoriamente divididos em 2 grupos (n=12): SU - sessão única e SM - sessão múltipla. Foram realizadas coletas microbiológica e de endotoxinas dos canais radiculares utilizando cone de pap... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract : Endotoxins originating from gram negatives bacterias are related to signals and clinical/radiographic symptoms. Therefore, reduction or elimination of endotoxins is essential to solve periapical inflammation. The aim of this dissertation was: Article 1 - To relate endotoxin levels and presence of clinical signs/symptoms and radiographic features in endodontic infection. Article 2 - To evaluate the effectiveness of supplemental photodynamic therapy (PDT) in optimizing the removal of bacteria and endotoxins from primarily infected root canals after one-visit and twovisit treatments. Methodology: Article 1 - Electronic searches were performed on Medline/PubMed, Embase, Cochrane Library, Scielo, Science Direct, Web of Knowledge and Scopus databases for identification of relevant studies published up to July 2016. Only reports in English were included. The selected literature was reviewed by two authors and classified as either suitable or unsuitable for inclusion in this review. The relationship between endotoxin levels and presence of clinical signs/symptoms and radiographic features were determined. Additionally, a metaanalysis was performed. Article 2 - 24 primarily infected root canals with apical periodontitis were selected and randomly divided into one-visit (n=12) and two-visit (n=12). Samples were collected before and after root canal procedures. Endotoxins were quantified by chromogenic limulus amebocyte lysate assay. Culture techniques were used to determine bacterial colony-forming unit counts. The systematic review and meta-analysis aimed to evaluate the relationship between endotoxin levels and presence of clinical signs/symptoms and radiographic features in patients with endodontic infection. Results: Article 1 - Among the 285 articles identified in the initial search, 29 were included for full-text appraisal and only eight studies met the inclusion criteria for this systematic review.... / Mestre

Thesis (M. D. S.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xi, 56 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 41-44).

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Feb. 5, 2008). Includes bibliographical references (p. 71-79).