The purpose of this study was to compare the resistance to fracture by the twisting of two nickel titanium (NiTi) rotary file systems. The Profile® GT® (GT) and the GT® Series X(TM) (GTX) files were tested to analyze the maximum torsional strength and the maximum angular deflection at the time of separation of the files. For each system, ten new files were tested at each of the following eight taper/size designations for a total of 160 files: 20/0.04, 20/0.06, 30/0.04, 30/0.06, 30/0.08, 40/0.04, 40/0.06, and 40/0.08. The American National Standards Institute / American Dental Association Specification No. 28 was implemented to evaluate torsional limits for these intruments. Files were mounted in a Maillefer Torsiometre machine, which records maximum torsional strength and angular deflection at separation for each file. A two-way ANOVA revealed significant differences after comparing the size and type of file. The GT files required significantly more torque to separate than the GTX files in all groups tested except the GTX file size 20/0.06, which required significantly more maximum torque than the GT file, with no significant difference between the GT and GTX files for size 30/0.04. The GT files exhibited values for angular deflection at separation that were significantly higher than those for the GTX files at sizes 30/0.04 and 40/0.08 and the GTX files exhibited higher values at size 30/0.08 with no significant difference between the brands at the remaining five file sizes. In summary, the GT files required significantly more torque to fracture and exhibited values for angular deflection at separation that were significantly higher than the GTX files for in 6 of 8 and 2 of 8 file sizes, respectively.

Orientador: Fredererico Canato Martinho / Co-orientador: Márcia Carneiro Carneiro Valera / Banca: Ana Paula Martins Gomes / Banca: Izabel Coelho Gomes Camões / Resumo: Os objetivos do presente estudo são: 1) Estudar o perfil inflamatório das lesões periapicais de dentes com infecções endodônticas primárias através dos níveis das citocinas inflamatórias: IL-1beta, IL-6, TNF-alfa; correlacionando com a presença de sintomatologia clínica; 2) Investigar os níveis das metaloproteinases [MMP-1, -2 e -9], inibidores de metaloproteinase [TIMP-1 e -2] e complexos MMP/TIMP [MMP1/TIMP1, MMP1/TIMP2, MMP2/TIMP1, MMP2/TIMP2, MMP9/TIMP1 e MMP9/TIMP2], presentes nos tecidos periapicais de dentes com infecções endodônticas primárias e lesão periapical; correlacionando com a presença de sintomatologia clínica e reabsorção óssea; 3) Correlacionar os níveis das citocinas inflamatórias [IL-1beta, IL-6 e TNF-alfa] e seus antagonistas [IL1-RA, IL6-RA, sTNF-R1], presentes nos tecidos periapicais; 4) Estudar a efetividade de diferentes medicações intracanal no controle do processo inflamatório periapical, através do monitoramento dos níveis de citocinas inflamatórias, [IL-1beta, IL-6, TNF-alfa], MMP's [MMP-1, -2 e -9], TIMP's [TIMP-1 e -2] e complexos [MMP1/TIMP1, MMP1/TIMP2, MMP2/TIMP1, MMP2/TIMP2 MMP9/TIMP1, MMP9/TIMP2] coletadas dos tecidos periapicais. Vinte dentes unirradiculares com necrose pulpar e lesão periapical foram selecionados. Após o preparo biomecânico (PBM) os dentes foram divididos aleatoriamente em 2 grupos de acordo com a medicação intracanal utilizada: Ca(OH)2+SSL [Ca(OH)2 + solução salina fisiológica]; e Ca(OH)2+CLX [Ca(OH)2 + clorexidina gel 2%]. Para a análise dos biomarcadores inflamatórios, foram realizadas coletas utilizando cones de papel estéril/apirogênico, ultrapassando 2 mm além ápice para obtenção do fluído intersticial. As coletas foram realizadas em dois momentos operatórios : coleta após PBM (Coleta inicial-CIF1) e coleta após 14 dias de medicação intracanal (Coleta final-CFF2). Citocinas... / Abstract: The aim of this study was: 1) To investigate the inflammatory profile of apical periodontitis disease present in primarily infected root canals determined by the levels of inflammatory cytokines : IL-1beta, IL-6, TNF-alfa; and to correlate with the presence of clinical features; 2) To investigate the levels of metalloproteinases [MMP-1, -2, -9], metalloproteinase inhibitors [TIMP-1 e -2] ; complexes MMP/TIMP [MMP1/ TIMP1, MMP1/TIMP2, MMP2/TIMP1, MMP2/TIMP2, MMP9/TIMP1 e MMP9/TIMP2], present in apical peridontitis disease from teeth with primary endodontic infection; and to correlate with the presence of clinical features; 3) To correlate the levels of IL-1beta, IL-6, TNF-alfa with their respectively antagonists - IL1-RA, IL6-RA, s TNF-R1, all present in apical peridontitis; 4) To evaluate the effectiveness of different root canal medications in the inflammatory process by monitoring the levels of inflammatory cytokines [IL-1beta, IL-6, TNF-alfa], MMP's [MMP-1,-2,-9]; TIMP [TIMP-1 and -2] and complexes [MMP1/TIMP1, MMP1/TIMP2, MMP2/TIMP1, MMP2/TIMP2, MMP9/TIMP1 e MMP9/TIMP2] in apical periodontitis. Twenty patients with single-rooted teeth that had necrotic pulp and periapical periodontitis will be selected. After BMP teeth will be randonly devided into 2 groups according to the root canal medication selection: Ca(OH)2+SSL [Ca(OH)2 + Saline Solution]; e Ca(OH)2+CHX [Ca(OH)2 + chlorhexidine gel 2%]. Samples will be collected from intersticial fluid by using sterile/ apyrogenic paper points. Samples will performed at two diferente times: After chemomechaical preparation (S1) and after 14 of root canal medication (S2). Inflammatory cytokines, metalloproteinases and their antagonists will be dosage by ELISA-assay. The levels of inflammatory cytokines, metalloproteinases and their antagonists will be typed on a spreadsheet and statiscally analyzed by SPSS for Windows and Statistic packpage 9.0. ... / Mestre

Thesis (M.D.S.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 119-130) Also available in print.

Purpose: This retrospective study was performed to assess the clinical and radiographic success rates of a non-vital formocresol and zinc oxide eugenol (ZOE) primary molar root canal therapy (RCT) technique. The effects of this treatment on the permanent successors and on exfoliation times were also investigated. Methods: The study included 161 patients with 211 primary molars treated by RCT by a single operator in a private pediatric dental office in the Toronto area. Results: A clinical success rate of 90.0% and a radiographic success rate of 77.3% were obtained. Enamel defects were found in 6.8% of permanent successors and in patients who were significantly younger at the time of root canal therapy treatment (p = .001). Treated molars exfoliated on average 5.8 months sooner than contralateral teeth (p<0.001). Conclusions: Formocresol and ZOE RCT is a viable treatment for necrotic primary molars and yielded very high clinical success rates with moderate radiographic success rates.

This study examined the use of phage therapy against Pseudomonas aeruginosa strain PA14 biofilms. Part 1: 24 and 96h PA14 biofilms grown in microplates were phage treated and bacterial biomass was quantified using crystal violet staining. Part 2: 24 and 96h PA14 biofilms grown in prepared root canals of human mandibular incisors were treated with phages and intra-canal samples using paper points and round burs were taken to assess phage and bacterial counts. Part 1: Two phages (JBD4 and JBD44a) were used. Treatment with phages produced significant reduction in the mean percentage of biomass in 24h (p<0.05) and 96h (p=0.08) biofilms. Part 2: In 24 and 96h biofilms in a root canal model, no significant difference was found in colony forming units after phage treatment (p>0.05). Phage application significantly reduced the biomass of 24 and 96h PA14 biofilms grown on microplates, but did not in the extracted tooth models.

Purpose: This retrospective study was performed to assess the clinical and radiographic success rates of a non-vital formocresol and zinc oxide eugenol (ZOE) primary molar root canal therapy (RCT) technique. The effects of this treatment on the permanent successors and on exfoliation times were also investigated. Methods: The study included 161 patients with 211 primary molars treated by RCT by a single operator in a private pediatric dental office in the Toronto area. Results: A clinical success rate of 90.0% and a radiographic success rate of 77.3% were obtained. Enamel defects were found in 6.8% of permanent successors and in patients who were significantly younger at the time of root canal therapy treatment (p = .001). Treated molars exfoliated on average 5.8 months sooner than contralateral teeth (p<0.001). Conclusions: Formocresol and ZOE RCT is a viable treatment for necrotic primary molars and yielded very high clinical success rates with moderate radiographic success rates.

This study examined the use of phage therapy against Pseudomonas aeruginosa strain PA14 biofilms. Part 1: 24 and 96h PA14 biofilms grown in microplates were phage treated and bacterial biomass was quantified using crystal violet staining. Part 2: 24 and 96h PA14 biofilms grown in prepared root canals of human mandibular incisors were treated with phages and intra-canal samples using paper points and round burs were taken to assess phage and bacterial counts. Part 1: Two phages (JBD4 and JBD44a) were used. Treatment with phages produced significant reduction in the mean percentage of biomass in 24h (p<0.05) and 96h (p=0.08) biofilms. Part 2: In 24 and 96h biofilms in a root canal model, no significant difference was found in colony forming units after phage treatment (p>0.05). Phage application significantly reduced the biomass of 24 and 96h PA14 biofilms grown on microplates, but did not in the extracted tooth models.

No description available.

<p>The objective of this study was to assess coronal discoloration due to four commonly used endodontic sealers with gutta-percha, using spectrophotometric analysis. Extracted human teeth were obturated with the experimental sealers and GP. The sealers that were tested included AH Plus, EndoRez, and Kerr Pulp Canal Sealer. The teeth were maintained in a moist environment at 37 C. Immediate pretreatment readings of the crowns of the extracted teeth with a spectrometer were used as baseline data. Subsequent readings were taken every two weeks for two months. Results were analysed using Wilcoxson Signed Rank sum test and Kruskal Wallis test.</p>

<p> <p>&nbsp / </p> </p> <p><font face="Times New Roman" size="3">The aim of this study was to compare the sealing ability of AH Plus sealer to the canal wall in the presence and absence of the smear layer.</font></p>