Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: In order to successfully treat an infected root canal system (RCS), it is required to locate all root canals and have an access path to the apex of each canal. This can be challenging in teeth with pulp canal obliteration (PCO), often leading to increased chair time and increased risk of iatrogenic errors. Guided endodontic access (GEA) combines information from a cone-beam computed tomography (CBCT) scan with an intra-oral scan to create a stent. GEA stents with or without fixation pins have been shown to be successful in accurately negotiating a RCS with PCO. Objective: Compare the degree of deviation and difference in 3D offset at the base to apical tip of the drill from the designed access path when a GEA stent with and without pin fixation is used to access tooth #8 with PCO. Materials and Methods: A 3-D printed maxillary model of an anonymous patient had a GEA stent designed using coDiagnonstiX software. The stent extended from tooth #3 to tooth #14 with the guide sleeve over tooth #8. Tooth #8 with no calcification, calcification to the cervical third, and calcification to the middle third of the RCS were designed in the coDiagnostiX software. Tooth #8 will be accessed using a 1.3 mm drill that fits a 1.3 mm sleeve used for both access and pin fixation. 15 of the 30 GEA samples will utilized pin fixation, while the other 15 samples did not utilize pin fixation. Following GEA in all 30 samples a CBCT was taken of each sample. Each post-operative CBCT was aligned with the pre-operative CBCT in the coDiagnostiX software. The coDiagnostiX software was able to calculate the degree of deviation and difference in 3D offset between the base and apical tip of the drill during GEA. Paired t-tests were used to test each group for significant differences in 3D offset between base and tip. Two-way ANOVA was used to evaluate the effects of pin fixation and calcification on the degree of deviation and the deviation of 3D offset of the entry point and tip. Results: There was a significant interaction between use of pin fixation and calcification level on the degree of deviation of GEA. GEA with pin fixation had a significantly larger degree of deviation than GEA without pin fixation with calcification extending to the middle third of the RCS. GEA with and without pin fixation did not have a significant difference when calcification extended to the cervical third of the RCS or no calcification was present. There was a significant interaction between use of pin fixation and calcification level on 3D offset difference. GEA with pin fixation had a significantly larger 3D offset difference than GEA with no pin fixation for calcification in the middle third of the RCS. For GEA with and without pin fixation there was no significant difference when calcification extended to the cervical third of the RCS or no calcification was present. Conclusion: The use of pin fixation did not result in a decrease of degree of deviation or difference in 3D offset during GEA access. It can be concluded that the use of pin fixation is not necessary for GEA of teeth with PCO when a full dentition is present to provide stability and retention of the stent. / 2022-06-21

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: During root canal treatment (RCT), an opening is made through the crown of the tooth to access and to disinfect the root canal system (RCS). Traditional endodontic access (TEA) may sacrifice tooth structure and weaken the tooth. Cone beam computed tomography (CBCT) provides information about the exact location of the root canals. This information can be used for the design of a canal-directed endodontic access (CDEA). It may also be used for the 3D printing of an acrylic endodontic stent that could help to create a conservative CDEA. Objective: 1) Evaluate the ability of the Dolphin 3D imaging software to assist in creating a CDEA; 2) Compare tooth structure loss in a CDEA to that in a TEA by measuring the volume of remaining tooth structure, surface area of the access opening at the occlusal, and remaining dentin thickness at the CEJ. Materials and Methods: Thirty extracted human mandibular premolars were used. Teeth with large, wide canals were excluded. CBCT images will be taken for all teeth using Kodak 9000. Fifteen teeth were randomly assigned to the TEA group and 15 teeth were assigned to the CDEA group. The CDEA path was mapped using Dolphin 3D imaging software. Acrylic access stents were designed using Rhino 3D software and printed using a 3D printer. The teeth were accessed through the corresponding stents. The 15 teeth that are part of the traditional access group were accessed without a stent. A CBCT scan was taken post-access for all 30 teeth. Wilcoxon Rank Sum Tests were performed to compare the following outcomes for the two groups: the volume of remaining tooth structure, the surface area of the access opening at the occlusal, and remaining dentin thickness at the CEJ. Results: The remaining dentin thickness (percent loss) was not significantly larger for TEA than for CDEA. The surface area (post-treatment) was significantly larger for TEA than for CDEA, and volume (percent loss) was significantly larger for TEA than for CDEA. Conclusion: The use of the CBCT and Dolphin 3D imaging provided an accurate and more conservative CDEA with the guide of an acrylic stent.

Indiana University-Purdue University Indianapolis (IUPUI) / Accurate determination of working length during endodontic therapy is critical in achieving a predictable and successful outcome. Working length is determined by the use of electronic apex locators, tactile perception, knowledge of average tooth lengths and dental radiography. Due to the increasing use of digital radiography in clinical practice, a comparison with conventional film in working length determination is justified. The purpose of this study is to determine if there is a difference between Schick digital radiography and Kodak Ultra-speed film in the accurate determination of working lengths when vertical angulation of the object is variable. Twelve teeth with #15 K-flex files at varying known lengths from the anatomical apex were mounted in a resin-plaster mix to simulate bone density. A mounting jig for the standardization of projection geometries allowed for exact changes in vertical angulation as it related to the object (tooth) and the film/sensor. Each tooth was imaged using Schick CDR and Kodak Ultra-speed film at varying angles with a consistent source-film distance and exposure time. Four dental professionals examined the images and films independently and measured the distance from the tip of the file to radiographic apex and recorded their results. The error in working length was calculated as the observed value minus the known working length for each tooth type. A mixed-effects, full-factorial analysis of variance (ANOVA) model was used to model the error in working length. Included in the ANOVA model were fixed effects for type of image, vertical angulation, and the interaction of angle and film type. Tooth type and examiner were included in the model as random effects assuming a compound symmetry covariance structure. The repeatability of each examiner, for each film type, was assessed by estimating the intra-class correlation coefficient (ICC). The ICC was determined when 12 randomly selected images and radiographs were reevaluated 10 days after initial measurements. The repeatability of each examiner for Schick CDR was good with ICCs ranging from 0.67 to 1.0. Repeatability for the conventional film was poor with ICCs varying from -0.29 to 0.55. We found the error in the working length was not significantly different between film types (p = 0.402). After adjusting for angle, we found that error in the working length from the digital image was only 0.02 mm greater (95-percent CI: -0.03, 0.06) than the conventional film. Furthermore, there was not a significant difference among the angles (p = 0.246) nor in the interaction of image type with angle (p = 0.149). Based on the results of our study, we conclude that there is not a statistically significant difference in determining working length between Schick CDR and Kodak Ektaspeed film when vertical angulation is modified.

O objetivo do presente estudo clínico foi compreender o efeito do uso prévio de agentes antimicrobianos na diversidade e a estrutura do microbioma procariótico de saliva, biofilme supragengival e canal radicular de dentes com infecção endodôntica aguda. Realizaram-se coletas microbiológicas de saliva (S), biofilme supragengival (BS) e canal radicular (CR) de pacientes que não utilizaram antibióticos (G1: n=6) e de pacientes que utilizaram antibióticos (G2: n=6). Para a caracterização das comunidades de procariotos por meio de sequenciamento de alto rendimento, foram produzidos pools de seis amostras para cada um dos sítios. A região hipervariável V3-V4 do gene 16S rRNA foi amplificada e a plataforma Illumina MiSeq foi empregada para análise das sequências geradas. Foram determinadas a presença e abundância relativa das unidades taxonômicas operacionais (OTUs) em cada amostra. Procedeu-se a análise de alfa-diversidade para cada amostra, considerando-se as métricas de Simpson, dominância, estimativa de riqueza de Chao-I e o Índice de Shannon. Os valores obtidos foram comparados por meio de testes estatísticos. Para a análise dos índices de beta-diversidade, empregou-se o método de agrupamento UPGMA, com jackknifing e método de comparação UniFrac com peso. A representação gráfica tridimensional da beta-diversidade foi realizada por meio de análise de coordenadas principais. A técnica de PCR gene específico foi empregada para determinar a presença de genes relacionados à resistência bacteriana para agentes beta-lactâmicos (blaTEM, blaZ, ampC, mecA), macrolídeos (ermB, ermC, mefA), tetraciclinas (tetM, tetQ, tetW), lincosamidas (lnuB, lsaB) e vancomicina (vanA, vanD, vanE). A similaridade para a presença/ausência de genes de resistência nas amostras de S, BS e CR em G1 e G2 foi determinada por meio de coeficiente de agrupamento, utilizando-se o método UPGMA com distância Euclidiana. Todos os pacientes apresentavam infecção endodôntica aguda, caracterizada pela presença de dor espontânea, necrose pulpar e dor à percussão vertical. Aumento de volume foi observado em 8/12 pacientes. Os pacientes do Grupo 2 utilizaram beta-lactâmicos previamente à consulta (amoxicilina = 5; cefalexina = 1). Há predomínio de integrantes do domínio Bactéria em todas S, BS e CR. Archaea pertencentes ao gênero Methanobrevibacter foram encontradas apenas em amostras de CR, constituindo menos de 1% do total de OTUs (G1-CR = 0,319%; G2-CR = 0,014%). Há predomínio de bactérias dos filos Firmicutes e Bacteroidetes em amostras de S, BS e CR. Há redução intensa no percentual de OTUs pertencentes ao Filo Firmicutes em amostras de saliva, quando antibiótico foi utilizado (G1-S = 75,371; G2-S = 35,242). Comportamento oposto ocorreu neste ecossistema para integrantes do Filo Bacteroidetes (G1-S = 12,657; G2-S = 33,947). Tanto em G1 quanto em G2, bactérias do gênero Streptococcus predominam em amostras de S e BS. Em canais radiculares, maiores percentuais de OTUs foram observados para os gêneros Porphyromonas e Prevotella. As métricas de alfadiversidade indicam que o uso prévio de antimicrobiano parece oportunizar o estabelecimento de espécies antes menos abundantes, especialmente em saliva (dominância: G1-S>G2-S; índice de Shanon: G1-S<G2-S; índice de Simpson: G1- S<G2-S; índice de Chao-1: G1-S<G2-S). A análise de beta-diversidade mostra proximidade entre G1-BS e G2-BS; há distanciamento entre G1-S e G2-S. As amostras G1-CR e G2-CR estão mais distantes de S e BS, sugerindo maior seleção imposta pelo ecossistema do CR aos procariotos. Os genes de resistência mais frequentemente detectados foram tetM, tetQ, tetM, ermB e mefA. Não foram detectados genes vanA, vanD, vanE, blaZ, mecA, lnuB e ermC. O gene ermB foi frequentemente detectado em amostras de S, BS e CR em ambos os grupos. Em pacientes que não utilizaram antibiótico, o gene tetM e o gene tetQ foram detectados simultaneamente em S, BS e CR (tetM = 4/6; tetQ = 3/6). A análise multivariada não demonstrou nível de agrupamento alto entre amostras de um mesmo paciente, de um mesmo ecossistema, ou de um mesmo grupo. A partir dos resultados do presente estudo, observou-se que a utilização de agente antimicrobiano betalactâmico parece alterar parâmetros composicionais de comunidades de procariotos na cavidade bucal. Entretanto, particularidades relativas a cada ecossistema podem modular a extensão deste efeito, parecendo ser mais intensos em amostras de S do que em BS e CR. / The present clinical study aimed to assess the effect of antibiotics over the diversity and structure in prokaryotic communities of saliva, supragengival biofilm and root canal of teeth with acute primary infections. Samples of saliva (S), supragengival biofilm (BS) and root canal of teeth with acute primary infections (CR) were collected from patients, and were grouped according with the previous use of antibiotic (G1 = no antibiotics; G2 = antibiotics). Pooled samples for each community were evaluated. DNA sequencing was performed with MiSeq (Illumina). The V3-V4 hypervariable region from the 16S rRNA gene was amplified. The presence and relative abundance of the operational taxonomic units (OTUs) was determined for each sample. Alpha-diversity analysis was performed with the Simpson’s index, dominance, Chao-1 richness index and Shannon’s index. Statistical analysis was carried out to compare their values for each community.Beta-diversity was computed through UPGMA clustering and jackknifing. The principal coordinate analysis employed weighted UniFrac. Gene-specific PCR was employed to detect resistance genes to lactamics (blaTEM, blaZ, ampC, mecA), macrolides (ermB, ermC, mefA), tetracyclines (tetM, tetQ, tetW), lincosamides (lnuB, lsaB) e vancomycin (vanA, vanD, vanE). The UPGA clustering analysis with Euclidean distance was applied to investigate the existence of similar groups of samples. A dendrogram was constructed to show the arrangement of the sample groups produced by clustering. All the patients had primary acute endodontic infections, with spontaneous pain, pulp necrosis and tenderness on percussion. Swelling was observed for 8 out of 12 patients. Patients from G2 had lactamics before the urgency appointment (amoxicillin = 5; cephalexin = 1). Bacteria were predominant in S, BS and CR samples. Archaea belonging to the genus Methanobrevibacter were only detected in RC samples and comprised less than 1% of all the OTUs G1-CR = 0.319%; G2-CR = 0.014%). The great majority of the detected OTUs in S, BS, and CR belonged to the phyla Firmicutes and Bacteroidetes. Reduction in the percentage of Firmicutes was observed in G2-S (G1-S = 75.371%; G2-S = 35.242%). A distinct behavior was demonstrated by the Bacteroidetes (G1- S = 12.657%; G2-S = 33.947%). Components belonging to the genus Streptococcus were predominant in S and BS, for both G1 and G2. CR harbored high percentage of species belonging to the genus Porphyromonas and Prevotella. The alpha-diversity indexes demonstrated that the G2-S had an increase in low abundant species (dominance: G1- S>G2-S; Shanon index: G1-S<G2-S; Simpson index: G1-S<G2-S; Chao-1 index: G1-S<G2- S). Beta-diversity showed that G1-BS and G2-BS had close spatial distribution. G1-CR and G2-CR were more distant from S and BS samples. The RC may promote a most intense species selection, due to environmental conditions. The most frequently detected genes associated with resistance to antibiotics were tetM, tetQ, tetM, ermB, and mefA. The genes vanA, vanD, vanE, blaZ, mecA, lnuB, and ermC were not detected in the samples. The gene ermB was frequently detected in S, BS and CR samples. In patients from G1, tetM and tetQ were detected simultaneously in all the three environments (tetM = 4/6; tetQ = 3/6). There was no clustering behavior for samples belonging to different environments in the same patients and between the same environment samples from different groups. An overall analysis from the data allows for suggesting that the use of lactamic agents may alter compositional parameters from prokaryotic communities in the oral cavity to different extents. Specific environmental characteristics from each site may modulate the effect that seemed to be more intense for S than for BS and CR.

Orientador: Mário Tanomaru Filho / Banca: Marco Antônio Húngaro Duarte / Banca: Paulo Sérgio Cerri / Resumo: A proposta do estudo foi avaliar a microbiota endodôntica de dentes de humanos sem vitalidade pulpar com ou sem lesão periapical visível radiograficamente por meio das técnicas de "Checkerboard DNA-DNA Hybridization" e cultura microbiológica. Foram utilizados 20 dentes unirradiculados, divididos em casos de necrose pulpar sem lesão periapical (Grupo I) e dentes com necrose pulpar e lesão periapical (Grupo II). A colheita do material do canal radicular foi realizada com lima K e cones de papel absorvente. Para a técnica de cultura, as amostras foram semeadas em meios As, Ask, Ms e Tio's, para avaliação da presença de microrganismos anaeróbios, aeróbios e facultativos. Para a técnica de "Checkerboard DNA-DNA Hybridization", foi realizado o processamento do DNA extraído das amostras e das sondas de DNA de 33 microrganismos. Os resultados mostraram nas duas técnicas empregadas a presença de microrganismos. A técnica de hibridação DNA - DNA checkerboard permitiu a identificação de 31 espécies diferentes no Grupo I e de 32 espécies diferentes no Grupo II. Fusobacterium nucleatum spp polymorphum (80%), Porphyromonas gingivalis (80%), Prevotella melaninogenica (90%) predominaram no Grupo I. As sondas Streptococcus mitis e Selenomonas noxia não foram detectadas em nenhuma amostra deste grupo. No Grupo II, Fusobacterium nucleatum spp polymorphum, Neisseria mucosa e Porphyromonas gingivalis foram detectadas em todos os casos e Selenomonas noxia não foi encontrada em nenhuma das amostras deste grupo. Houve tendência para maior presença de bactérias anaeróbias obrigatórias moderadas no Grupo II, embora sem diferença significante (p>0,05), em relação ao Grupo I, de acordo com a cultura microbiológica. Foi observada maior freqüência de espécies bacterianas anaeróbias obrigatórias moderadas nos canais radiculares, tanto para o Grupo I como para o Grupo II, de acordo com a técnica de hibridação DNA-DNA checkerboard. / Abstract: The purpose of this study was to evaluate the endodontic microbiota from human's teeth, with no pulp vitality, with or without radiographic chronic periapical lesion, using a culture microbiologic method and checkerboard DNA-DNA hybridization technique. The whole sample, with 20 single root's teeth, was collected and divided into: teeth with no pulp vitality without periapical lesion (Group I) and teeth with no pulp vitality with periapical lesion (Group II). The samples were obtained with K file and absorbent paper points. To the culture technique, the samples were grown by using media like As, Ask, Ms and Tio's. To checkerboard DNA-DNA hybridization technique, the samples of DNA extracted crossed with microorganisms' DNA obtained from ATCC. The results demonstrated in two techniques used that in all the samples identified microorganisms, at least 20 ufc/ml. The checkerboard DNA-DNA hybridization technique demonstrated the identification of 31 different species of microorganisms in Group I and 32 different species of microorganisms in Group II. Fusobacterium nucleatum spp polymorphum (80%), Porphyromonas gingivalis (80%), Prevotella melaninogenica (90%) predominated in Group I. The probes Streptococcus mitis and Selenomonas noxia were not detected in no sample in this group. At Group II, Fusobacterium nucleatum spp polymorphum, Neisseria mucosa and Porphyromonas gingivalis were detected in all cases, and Selenomonas noxia was not present in sample of this group. It was tendency to greater number strict anaerobe microorganisms in Group II, however without statistical significance (p>0.05), in relation Group I, in accord with culture microbiologic method. It was detected a greater frequency of anaerobe strict microorganisms species in root canal, in both Groups I and II, in accord with the checkerboard DNA-DNA hybridization technique. / Mestre

O objetivo do presente estudo clínico foi compreender o efeito do uso prévio de agentes antimicrobianos na diversidade e a estrutura do microbioma procariótico de saliva, biofilme supragengival e canal radicular de dentes com infecção endodôntica aguda. Realizaram-se coletas microbiológicas de saliva (S), biofilme supragengival (BS) e canal radicular (CR) de pacientes que não utilizaram antibióticos (G1: n=6) e de pacientes que utilizaram antibióticos (G2: n=6). Para a caracterização das comunidades de procariotos por meio de sequenciamento de alto rendimento, foram produzidos pools de seis amostras para cada um dos sítios. A região hipervariável V3-V4 do gene 16S rRNA foi amplificada e a plataforma Illumina MiSeq foi empregada para análise das sequências geradas. Foram determinadas a presença e abundância relativa das unidades taxonômicas operacionais (OTUs) em cada amostra. Procedeu-se a análise de alfa-diversidade para cada amostra, considerando-se as métricas de Simpson, dominância, estimativa de riqueza de Chao-I e o Índice de Shannon. Os valores obtidos foram comparados por meio de testes estatísticos. Para a análise dos índices de beta-diversidade, empregou-se o método de agrupamento UPGMA, com jackknifing e método de comparação UniFrac com peso. A representação gráfica tridimensional da beta-diversidade foi realizada por meio de análise de coordenadas principais. A técnica de PCR gene específico foi empregada para determinar a presença de genes relacionados à resistência bacteriana para agentes beta-lactâmicos (blaTEM, blaZ, ampC, mecA), macrolídeos (ermB, ermC, mefA), tetraciclinas (tetM, tetQ, tetW), lincosamidas (lnuB, lsaB) e vancomicina (vanA, vanD, vanE). A similaridade para a presença/ausência de genes de resistência nas amostras de S, BS e CR em G1 e G2 foi determinada por meio de coeficiente de agrupamento, utilizando-se o método UPGMA com distância Euclidiana. Todos os pacientes apresentavam infecção endodôntica aguda, caracterizada pela presença de dor espontânea, necrose pulpar e dor à percussão vertical. Aumento de volume foi observado em 8/12 pacientes. Os pacientes do Grupo 2 utilizaram beta-lactâmicos previamente à consulta (amoxicilina = 5; cefalexina = 1). Há predomínio de integrantes do domínio Bactéria em todas S, BS e CR. Archaea pertencentes ao gênero Methanobrevibacter foram encontradas apenas em amostras de CR, constituindo menos de 1% do total de OTUs (G1-CR = 0,319%; G2-CR = 0,014%). Há predomínio de bactérias dos filos Firmicutes e Bacteroidetes em amostras de S, BS e CR. Há redução intensa no percentual de OTUs pertencentes ao Filo Firmicutes em amostras de saliva, quando antibiótico foi utilizado (G1-S = 75,371; G2-S = 35,242). Comportamento oposto ocorreu neste ecossistema para integrantes do Filo Bacteroidetes (G1-S = 12,657; G2-S = 33,947). Tanto em G1 quanto em G2, bactérias do gênero Streptococcus predominam em amostras de S e BS. Em canais radiculares, maiores percentuais de OTUs foram observados para os gêneros Porphyromonas e Prevotella. As métricas de alfadiversidade indicam que o uso prévio de antimicrobiano parece oportunizar o estabelecimento de espécies antes menos abundantes, especialmente em saliva (dominância: G1-S>G2-S; índice de Shanon: G1-S<G2-S; índice de Simpson: G1- S<G2-S; índice de Chao-1: G1-S<G2-S). A análise de beta-diversidade mostra proximidade entre G1-BS e G2-BS; há distanciamento entre G1-S e G2-S. As amostras G1-CR e G2-CR estão mais distantes de S e BS, sugerindo maior seleção imposta pelo ecossistema do CR aos procariotos. Os genes de resistência mais frequentemente detectados foram tetM, tetQ, tetM, ermB e mefA. Não foram detectados genes vanA, vanD, vanE, blaZ, mecA, lnuB e ermC. O gene ermB foi frequentemente detectado em amostras de S, BS e CR em ambos os grupos. Em pacientes que não utilizaram antibiótico, o gene tetM e o gene tetQ foram detectados simultaneamente em S, BS e CR (tetM = 4/6; tetQ = 3/6). A análise multivariada não demonstrou nível de agrupamento alto entre amostras de um mesmo paciente, de um mesmo ecossistema, ou de um mesmo grupo. A partir dos resultados do presente estudo, observou-se que a utilização de agente antimicrobiano betalactâmico parece alterar parâmetros composicionais de comunidades de procariotos na cavidade bucal. Entretanto, particularidades relativas a cada ecossistema podem modular a extensão deste efeito, parecendo ser mais intensos em amostras de S do que em BS e CR. / The present clinical study aimed to assess the effect of antibiotics over the diversity and structure in prokaryotic communities of saliva, supragengival biofilm and root canal of teeth with acute primary infections. Samples of saliva (S), supragengival biofilm (BS) and root canal of teeth with acute primary infections (CR) were collected from patients, and were grouped according with the previous use of antibiotic (G1 = no antibiotics; G2 = antibiotics). Pooled samples for each community were evaluated. DNA sequencing was performed with MiSeq (Illumina). The V3-V4 hypervariable region from the 16S rRNA gene was amplified. The presence and relative abundance of the operational taxonomic units (OTUs) was determined for each sample. Alpha-diversity analysis was performed with the Simpson’s index, dominance, Chao-1 richness index and Shannon’s index. Statistical analysis was carried out to compare their values for each community.Beta-diversity was computed through UPGMA clustering and jackknifing. The principal coordinate analysis employed weighted UniFrac. Gene-specific PCR was employed to detect resistance genes to lactamics (blaTEM, blaZ, ampC, mecA), macrolides (ermB, ermC, mefA), tetracyclines (tetM, tetQ, tetW), lincosamides (lnuB, lsaB) e vancomycin (vanA, vanD, vanE). The UPGA clustering analysis with Euclidean distance was applied to investigate the existence of similar groups of samples. A dendrogram was constructed to show the arrangement of the sample groups produced by clustering. All the patients had primary acute endodontic infections, with spontaneous pain, pulp necrosis and tenderness on percussion. Swelling was observed for 8 out of 12 patients. Patients from G2 had lactamics before the urgency appointment (amoxicillin = 5; cephalexin = 1). Bacteria were predominant in S, BS and CR samples. Archaea belonging to the genus Methanobrevibacter were only detected in RC samples and comprised less than 1% of all the OTUs G1-CR = 0.319%; G2-CR = 0.014%). The great majority of the detected OTUs in S, BS, and CR belonged to the phyla Firmicutes and Bacteroidetes. Reduction in the percentage of Firmicutes was observed in G2-S (G1-S = 75.371%; G2-S = 35.242%). A distinct behavior was demonstrated by the Bacteroidetes (G1- S = 12.657%; G2-S = 33.947%). Components belonging to the genus Streptococcus were predominant in S and BS, for both G1 and G2. CR harbored high percentage of species belonging to the genus Porphyromonas and Prevotella. The alpha-diversity indexes demonstrated that the G2-S had an increase in low abundant species (dominance: G1- S>G2-S; Shanon index: G1-S<G2-S; Simpson index: G1-S<G2-S; Chao-1 index: G1-S<G2- S). Beta-diversity showed that G1-BS and G2-BS had close spatial distribution. G1-CR and G2-CR were more distant from S and BS samples. The RC may promote a most intense species selection, due to environmental conditions. The most frequently detected genes associated with resistance to antibiotics were tetM, tetQ, tetM, ermB, and mefA. The genes vanA, vanD, vanE, blaZ, mecA, lnuB, and ermC were not detected in the samples. The gene ermB was frequently detected in S, BS and CR samples. In patients from G1, tetM and tetQ were detected simultaneously in all the three environments (tetM = 4/6; tetQ = 3/6). There was no clustering behavior for samples belonging to different environments in the same patients and between the same environment samples from different groups. An overall analysis from the data allows for suggesting that the use of lactamic agents may alter compositional parameters from prokaryotic communities in the oral cavity to different extents. Specific environmental characteristics from each site may modulate the effect that seemed to be more intense for S than for BS and CR.

O objetivo do presente estudo clínico foi compreender o efeito do uso prévio de agentes antimicrobianos na diversidade e a estrutura do microbioma procariótico de saliva, biofilme supragengival e canal radicular de dentes com infecção endodôntica aguda. Realizaram-se coletas microbiológicas de saliva (S), biofilme supragengival (BS) e canal radicular (CR) de pacientes que não utilizaram antibióticos (G1: n=6) e de pacientes que utilizaram antibióticos (G2: n=6). Para a caracterização das comunidades de procariotos por meio de sequenciamento de alto rendimento, foram produzidos pools de seis amostras para cada um dos sítios. A região hipervariável V3-V4 do gene 16S rRNA foi amplificada e a plataforma Illumina MiSeq foi empregada para análise das sequências geradas. Foram determinadas a presença e abundância relativa das unidades taxonômicas operacionais (OTUs) em cada amostra. Procedeu-se a análise de alfa-diversidade para cada amostra, considerando-se as métricas de Simpson, dominância, estimativa de riqueza de Chao-I e o Índice de Shannon. Os valores obtidos foram comparados por meio de testes estatísticos. Para a análise dos índices de beta-diversidade, empregou-se o método de agrupamento UPGMA, com jackknifing e método de comparação UniFrac com peso. A representação gráfica tridimensional da beta-diversidade foi realizada por meio de análise de coordenadas principais. A técnica de PCR gene específico foi empregada para determinar a presença de genes relacionados à resistência bacteriana para agentes beta-lactâmicos (blaTEM, blaZ, ampC, mecA), macrolídeos (ermB, ermC, mefA), tetraciclinas (tetM, tetQ, tetW), lincosamidas (lnuB, lsaB) e vancomicina (vanA, vanD, vanE). A similaridade para a presença/ausência de genes de resistência nas amostras de S, BS e CR em G1 e G2 foi determinada por meio de coeficiente de agrupamento, utilizando-se o método UPGMA com distância Euclidiana. Todos os pacientes apresentavam infecção endodôntica aguda, caracterizada pela presença de dor espontânea, necrose pulpar e dor à percussão vertical. Aumento de volume foi observado em 8/12 pacientes. Os pacientes do Grupo 2 utilizaram beta-lactâmicos previamente à consulta (amoxicilina = 5; cefalexina = 1). Há predomínio de integrantes do domínio Bactéria em todas S, BS e CR. Archaea pertencentes ao gênero Methanobrevibacter foram encontradas apenas em amostras de CR, constituindo menos de 1% do total de OTUs (G1-CR = 0,319%; G2-CR = 0,014%). Há predomínio de bactérias dos filos Firmicutes e Bacteroidetes em amostras de S, BS e CR. Há redução intensa no percentual de OTUs pertencentes ao Filo Firmicutes em amostras de saliva, quando antibiótico foi utilizado (G1-S = 75,371; G2-S = 35,242). Comportamento oposto ocorreu neste ecossistema para integrantes do Filo Bacteroidetes (G1-S = 12,657; G2-S = 33,947). Tanto em G1 quanto em G2, bactérias do gênero Streptococcus predominam em amostras de S e BS. Em canais radiculares, maiores percentuais de OTUs foram observados para os gêneros Porphyromonas e Prevotella. As métricas de alfadiversidade indicam que o uso prévio de antimicrobiano parece oportunizar o estabelecimento de espécies antes menos abundantes, especialmente em saliva (dominância: G1-S>G2-S; índice de Shanon: G1-S<G2-S; índice de Simpson: G1- S<G2-S; índice de Chao-1: G1-S<G2-S). A análise de beta-diversidade mostra proximidade entre G1-BS e G2-BS; há distanciamento entre G1-S e G2-S. As amostras G1-CR e G2-CR estão mais distantes de S e BS, sugerindo maior seleção imposta pelo ecossistema do CR aos procariotos. Os genes de resistência mais frequentemente detectados foram tetM, tetQ, tetM, ermB e mefA. Não foram detectados genes vanA, vanD, vanE, blaZ, mecA, lnuB e ermC. O gene ermB foi frequentemente detectado em amostras de S, BS e CR em ambos os grupos. Em pacientes que não utilizaram antibiótico, o gene tetM e o gene tetQ foram detectados simultaneamente em S, BS e CR (tetM = 4/6; tetQ = 3/6). A análise multivariada não demonstrou nível de agrupamento alto entre amostras de um mesmo paciente, de um mesmo ecossistema, ou de um mesmo grupo. A partir dos resultados do presente estudo, observou-se que a utilização de agente antimicrobiano betalactâmico parece alterar parâmetros composicionais de comunidades de procariotos na cavidade bucal. Entretanto, particularidades relativas a cada ecossistema podem modular a extensão deste efeito, parecendo ser mais intensos em amostras de S do que em BS e CR. / The present clinical study aimed to assess the effect of antibiotics over the diversity and structure in prokaryotic communities of saliva, supragengival biofilm and root canal of teeth with acute primary infections. Samples of saliva (S), supragengival biofilm (BS) and root canal of teeth with acute primary infections (CR) were collected from patients, and were grouped according with the previous use of antibiotic (G1 = no antibiotics; G2 = antibiotics). Pooled samples for each community were evaluated. DNA sequencing was performed with MiSeq (Illumina). The V3-V4 hypervariable region from the 16S rRNA gene was amplified. The presence and relative abundance of the operational taxonomic units (OTUs) was determined for each sample. Alpha-diversity analysis was performed with the Simpson’s index, dominance, Chao-1 richness index and Shannon’s index. Statistical analysis was carried out to compare their values for each community.Beta-diversity was computed through UPGMA clustering and jackknifing. The principal coordinate analysis employed weighted UniFrac. Gene-specific PCR was employed to detect resistance genes to lactamics (blaTEM, blaZ, ampC, mecA), macrolides (ermB, ermC, mefA), tetracyclines (tetM, tetQ, tetW), lincosamides (lnuB, lsaB) e vancomycin (vanA, vanD, vanE). The UPGA clustering analysis with Euclidean distance was applied to investigate the existence of similar groups of samples. A dendrogram was constructed to show the arrangement of the sample groups produced by clustering. All the patients had primary acute endodontic infections, with spontaneous pain, pulp necrosis and tenderness on percussion. Swelling was observed for 8 out of 12 patients. Patients from G2 had lactamics before the urgency appointment (amoxicillin = 5; cephalexin = 1). Bacteria were predominant in S, BS and CR samples. Archaea belonging to the genus Methanobrevibacter were only detected in RC samples and comprised less than 1% of all the OTUs G1-CR = 0.319%; G2-CR = 0.014%). The great majority of the detected OTUs in S, BS, and CR belonged to the phyla Firmicutes and Bacteroidetes. Reduction in the percentage of Firmicutes was observed in G2-S (G1-S = 75.371%; G2-S = 35.242%). A distinct behavior was demonstrated by the Bacteroidetes (G1- S = 12.657%; G2-S = 33.947%). Components belonging to the genus Streptococcus were predominant in S and BS, for both G1 and G2. CR harbored high percentage of species belonging to the genus Porphyromonas and Prevotella. The alpha-diversity indexes demonstrated that the G2-S had an increase in low abundant species (dominance: G1- S>G2-S; Shanon index: G1-S<G2-S; Simpson index: G1-S<G2-S; Chao-1 index: G1-S<G2- S). Beta-diversity showed that G1-BS and G2-BS had close spatial distribution. G1-CR and G2-CR were more distant from S and BS samples. The RC may promote a most intense species selection, due to environmental conditions. The most frequently detected genes associated with resistance to antibiotics were tetM, tetQ, tetM, ermB, and mefA. The genes vanA, vanD, vanE, blaZ, mecA, lnuB, and ermC were not detected in the samples. The gene ermB was frequently detected in S, BS and CR samples. In patients from G1, tetM and tetQ were detected simultaneously in all the three environments (tetM = 4/6; tetQ = 3/6). There was no clustering behavior for samples belonging to different environments in the same patients and between the same environment samples from different groups. An overall analysis from the data allows for suggesting that the use of lactamic agents may alter compositional parameters from prokaryotic communities in the oral cavity to different extents. Specific environmental characteristics from each site may modulate the effect that seemed to be more intense for S than for BS and CR.

Orientador: Eduardo Galera da Silva / Banca: Claudio Hideki Kubo / Banca: Rodrigo Máximo de Araújo / Resumo: Para que o tratamento endodôntico tenha sucesso, buscam-se meios de realizar uma limpeza eficiente e modelagem adequada do canal radicular. No entanto, na prática clínica, alguns problemas podem ser encontrados durante a instrumentação, sendo um deles a formação de micro trincas e linhas de fratura, que podem evoluir após o estresse causado pelas forças oclusais e resultar em uma fratura completa da raiz. O presente estudo teve por objetivo avaliar a incidência de micro trincas dentinárias em 48 incisivos inferiores humanos extraídos, utilizando estereomicroscópio e Tomografia Computadorizada de Feixe Cônico (TCFC), após o preparo do canal radicular com o sistema ProDesign S (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brasil) em movimento rotatório e reciprocante, o sistema ProDesign R (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brasil) em movimento reciprocante e o sistema Reciproc (VDW, Munich, Germany) em movimento reciprocante. Além disso, buscouse analisar a superfície dos instrumentos quando sem uso, após o primeiro uso, e sucessivamente até o terceiro uso, através de estereomicroscópio e microscopia eletrônica de varredura. Os resultados foram submetidos à análise estatística por meio da Prova de Friedman. Houve formação de micro trincas dentinárias em todos os grupos avaliados em Estereomicroscópio após o preparo do canal radicular utilizando o sistema ProDesign S em movimento rotatório e reciprocante, o sistema ProDesign R em movimento reciprocant... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: So that the endodontic treatment is successful, means to achieve an efficient cleaning and proper modeling of root canal are sought. However, in clinical practice, some problems may be encountered during the instrumentation, one of them being the formation of micro cracks and lines of fracture, which may evolve after the stress caused by occlusal forces and result in a complete root fracture. The objective of this study is to evaluate the incidence of dentin micro cracks in 48 extracted human incisors using stereomicroscope and cone beam computed tomography (TCFC), after the root canal preparation with ProDesign S system (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil), in rotatory and reciprocating movement, ProDesign R system (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil) in reciprocating movement and Reciproc system (VDW, Munich, Germany) in reciprocating movement. In addition, it was aimed to analyze the instruments surface when without use, after first use, and successively until the third use, through a stereomicroscope and scanning electron microscopy. The results will be subjected to statistical analysis by means of the Friedman test. Dentin micro cracks were formed in all groups evaluated in a stereomicroscope after root canal preparation using the ProDesign S system in rotating and reciprocating motion, the ProDesign R system in reciprocating motion and the Reciproc system in reciprocating motion; but without statistically significant dif... (Complete abstract click electronic access below) / Mestre

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: One of the challenges of non-surgical root canal treatment (NSRCT) is determining the working length of the canal which indicates the exact end point of root canal preparation and obturation. The development of the Electronic Apex Locator (EAL) has helped the clinician to determine the location of the apical foramen, and hence the working length, when performing NSRCT. Objective: The objective of this in vitro study was to determine the accuracy of a new EAL, the E-PEX (Changzhou Eighteeth Medical Technology Co., China), and compare it to a commonly used EAL, the Root ZX II (J. Morita Corp, Kyoto, Japan), for determining the location of the apical foramen. Materials and Methods: Twenty extracted single rooted teeth were used in this study. The crowns were removed and the distance from a coronal reference point to the apical foramen was measured utilizing a k-file and direct visualization under magnification. Teeth were then mounted in alginate and measurements for the apical foramen were made using the Root ZX II and the E-PEX. The difference between the actual canal length and the electronic length was then calculated and compared. Results: The mean true difference was -0.20, and -0.19 for the E-PEX and Root ZX II respectively. The mean absolute difference was 0.28, and 0.26 for the E-PEX and Root ZX II respectively. Paired t-tests done separately for true differences (p = 0.45) and absolute differences (p = 0.21) showed no significant difference among EALs. The percentage of measurements falling within 0.5 mm of the actual canal lengths for each EAL were 95% and 90% for the E-PEX and Root ZX II respectively. McNemar’s test was used to compare between the two test methods for the percentage within 0.5 mm and revealed no significant difference (p = 0.32). Conclusion: The Root ZX II had an average measurement that was slightly closer to the actual length of the canal when compared to the E-PEX, while the E-PEX had a higher percentage of measurement within 0.5 mm of the apical foramen. However, these differences were not statistically significant.

Made available in DSpace on 2017-07-24T19:22:20Z (GMT). No. of bitstreams: 1 Andres Felipe Cartagena Molina.pdf: 3076315 bytes, checksum: 06060dc51df633a32dd15312c25f51cd (MD5) Previous issue date: 2012-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Endodontically treated molars generally present reduced crown structure, with a greater risk of biomechanical failure when compared with living teeth, restoration technique thereof being a challenge for dental profession. The aim of this paper was to analyze, using the finite elements method (FEM), the stresses distribution in a first molar restored with the Endocrown technique, after simulating functional forces. A lithium disilicate ceramic (IPSe.max Press) and a second generation indirect resin composite (SR Adoro) were used as restorative materials, adhesively cemented to the tooth with a dual polymerization luting agent (Variolink II). In order to obtain their mechanical properties, specimens of these materials were subjected to compressive and diametral tensile strength tests 24 h after manipulation. Based on a CAT scan of the lower third of the face, a 3D model of tooth 36 endodontically treated was simulated. Tooth was sectioned nearly 1 mm above the enamel margin, inner angles were rounded, a layer of 0.05 mm of luting agent was manufactured and the remnant of the original tooth was modeled with both restorative materials. The following models were obtained: Model 1, Endocrown in SR Adoro under axial load; Model 2, Endocrown in IPSe.max Press under axial load; Model 3, Endocrown in SR Adoro under oblique load; Model 4, Endocrown in IPS e.max Press under oblique load. Each model was subjected to a force of 100 N. The strength of the luting and restorative materials and of tooth tissues was evaluated using the Mohr Coulomb (MC) failure criterion, and tensile and compressive contact stresses and shear stresses at the adhesive interface were analyzed. As a result of simulations, according to the MC criterion, Model 2 proved to be 17% better than Model 1, and Models 3 and 4 showed failures in the restorative material. In the adhesive cement and enamel, both for axial and oblique loads, it was found that distribution of stresses was more homogeneous for models with more rigid restorative material, behavior which is repeated in the analysis of tensile and compressive contact stresses and shear stresses. Based on the results obtained, it was possible to conclude that Endocrown restorations, when perfectly cemented and made of ceramic are more resistant to fracture than composite Endocrown. Loads of the oblique direction represent a critical point in the success of the restoration, integrity of the margin and conservation of the tooth remaining. / Dentes tratados endodonticamente apresentam geralmente reduzida estrutura coronária e grande risco de falha biomecânica, quando comparados com dentes vitalizados, sendo, portanto, sua técnica restauradora um desafio para a Odontologia. O objetivo do presente estudo foi analisar, usando o método de elementos finitos (MEF), a distribuição de tensões em um primeiro molar restaurado com a técnica Endocrown, após a simulação de cargas oclusais funcionais. Uma cerâmica à base de dissilicato de lítio (IPSe.max Press) e uma resina composta laboratorial de segunda geração (SR Adoro) foram selecionadas como materiais restauradores, cimentados adesivamente ao dente por uma camada cimento de polimerização dual (Variolink II). Com o objetivo de obter suas propriedades mecânicas, corpos de prova dos materiais cimentante e restaurador foram submetidos a testes de resistência a compressão e tração diametral 24 h após sua manipulação. Utilizando-se uma tomografia do terço inferior da face, um modelo 3D do dente 36 com tratamento endodôntico foi obtido. O dente foi seccionado aproximadamente 1 mm acima do limite amelocementário, os ângulos internos do preparo foram arredondados, uma película de 0,05 mm de cimento foi construída e o restante do dente foi modelado com ambos os materiais restauradores. Foram obtidos os seguintes modelos: Modelo 1, Endocrown confeccionada em SR Adoro submetida a carga axial; Modelo 2, Endocrown confeccionada em IPSe.max Press submetida a carga axial; Modelo 3, Endocrown confeccionada em SR Adoro submetida a carga oblíqua; Modelo 4, Endocrown confeccionada em IPSe.max Press submetida a carga oblíqua. Cada modelo foi submetido a carga de 100 N. A resistência dos materiais cimentante e restauradores e também dos tecidos dentais foi avaliada segundo o critério de falha de Mohr Coulomb (MC), e as tensões de tração e de compressão de contato e as de cisalhamento na interface adesiva foram calculadas. De acordo com os resultados das simulações, segundo o critério de MC, o Modelo 2 demonstrou ser 17% superior ao 1, e os Modelos 3 e 4 demonstraram falha do material restaurador. A distribuição de tensões no cimento e no esmalte dentário, tanto para carga axial quanto para oblíqua, foi mais homogênea nos modelos restaurados com o material mais rígido, comportamento esse que se repetiu na análise de tensões de tração e compressão e de cisalhamento na interface. Concluiu-se que restaurações Endocrowns, se cimentadas adequadamente e confeccionadas em cerâmica, são mais resistentes à fratura do que as de resina laboratorial. As cargas oblíquas representam um ponto crítico para o sucesso da restauração, da sua integridade marginal e da conservação do remanescente dental.