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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Influência de técnicas de moldagem com e sem casquetes na exatidão dimensional de modelos de gesso e adaptação marginal de infraestruturas em zircônia / Influence of impression techniques with and without acrylic copings on the dimensional accuracy of gypsum casts and marginal fit of zirconia frameworks

Silva, Stephania Caroline Rodolfo [UNESP] 20 June 2016 (has links)
Submitted by Stephania Caroline Rodolfo Silva null (stephaniacrsilva@foar.unesp.br) on 2016-08-18T20:52:01Z No. of bitstreams: 1 Dissertação Defesa Stephania C. R. Silva 18.08.pdf: 885533 bytes, checksum: cf1bd5bf272a148a2e397dbde32c3029 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-19T20:19:26Z (GMT) No. of bitstreams: 1 silva_scr_me_arafo.pdf: 885533 bytes, checksum: cf1bd5bf272a148a2e397dbde32c3029 (MD5) / Made available in DSpace on 2016-08-19T20:19:26Z (GMT). No. of bitstreams: 1 silva_scr_me_arafo.pdf: 885533 bytes, checksum: cf1bd5bf272a148a2e397dbde32c3029 (MD5) Previous issue date: 2016-06-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente estudo analisou a exatidão de modelos de gesso, obtidos a partir de diferentes técnicas de moldagem, incluindo casquetes individuais, isolados ou unidos, bem como mensurou o desajuste marginal cervical de infraestruturas de zircônia sobre preparos dentais para coroa total. Foi utilizado um modelo mestre (controle), com preparos nos dentes 14, 16, 21 e 25, sobre o qual infraestruturas de zircônia foram confeccionadas por tecnologia CAD/CAM. Para cada técnica de moldagem: simultânea com silicone de condensação (T1a), ou adição (T1b); casquetes individuais isolados (T2); unidos com cilindros de resina acrílica (T3); unidos com cilindros metálicos (T4); foram obtidos 8 moldes totais, por único operador calibrado, com moldeira de estoque. As moldagens com casquetes foram realizadas com poliéter e as transferências com silicone de condensação. Para a análise da adaptação marginal cervical das infraestruturas de zircônia, as mesmas foram passivamente adaptadas sobre os preparos nos modelos de gesso, sendo as mensurações do desajuste marginal cervical realizadas em estereomicroscópio (50x). Para a análise de exatidão dimensional linear oclusal global, os modelos foram escaneados e, a partir de três pontos pré-definidos, realizadas mensurações látero-laterais (LL) e anteroposteriores (AP) bilaterais do arco dental no programa ImageJ. Além disso, mensurações das dimensões áxio-cervicais de cada preparo e da distância entre os preparos do segmento 14-16 foram realizadas com paquímetro digital. Métodos estatísticos (α=0,05) foram empregados para avaliar a influência das técnicas de moldagem. Para o desajuste cervical, não houve diferença (p>0,05) para o dente 21. Para os dentes 14 e 16, apenas a técnica com casquetes individuais isolados apresentou diferença (p<0,05) em relação ao controle; enquanto para o dente 25 todas as técnicas com casquetes diferiram (p<0,05) do controle. Na mensuração da exatidão dimensional global, nenhuma técnica apresentou diferença (p>0,05) em relação ao controle. Para as mensurações áxio-cervicais do dente 25, todas as técnicas com casquete foram diferentes (p<0,05) do controle. Não houve diferença (p>0,05) nas dimensões do dente 21 e da distância interpreparos do segmento 14-16. De maneira geral, a técnica com casquetes isolados produziu modelos com maior desajuste marginal cervical. A forma de união dos casquetes, não apresentou influência sobre a exatidão dos modelos. / This study examined the accuracy of gypsum casts obtained from different impression techniques, including individual acrylic copings, and measured the cervical misfit of zirconia frameworks on dental preparations for fixed prosthodontics. A master cast with preparations in the teeth #14, 16, 21 and 25, on which zirconia frameworks were made by CAD/CAM technology, was used as control (baseline measurements). For each impression technique: single-step with condensation silicone (T1a), or vinyl polysiloxane (T1b); individual acrylic copings (T2); acrylic copings bonded with acrylic resin cylinders (T3) or metal cylinders (T4), 8 impressions were obtained by a single calibrated operator using stock trays. For the techniques T2, T3 and T4, polyether was used into the acrylic copings and condensation silicone was used for their pick-up. For the analysis of cervical marginal fit, zirconia frameworks were passively seated on the dental preparations of the gypsum casts, and measurements of cervical misfit calculated in stereo (50x). For the analysis of occlusal linear dimensional accuracy, the casts were scanned and, from three pre-defined points, side-to-side (LL) and bilateral anteroposterior (AP) measurements were performed by means of digitized images in the ImageJ software. Additionally, measurements of axio-cervical dimensions of each dental preparation and the distance between the preparations of the #14-16 fixed prosthodontics’ segment were taken with a digital caliper. Statistical analyzes (α=.05) were used to evaluate the influence of impression techniques. For cervical misfit, there was no difference (p>.05) for the tooth #21. For the teeth #14 and 16, only the technique T2 showed significant difference (p<.05) comparing to control; while for the tooth #25 all techniques with acrylic copings (T2, T3 and T4) differ (p<.05) from control. No significant differences were found among the techniques and the control (master cast) for the occlusal linear dimensions (p>.05). For axio-cervical measurements of tooth #25, all techniques using acrylic copings differ (p<.05) from control. There was no difference (p>.05) in the axio-cervical dimensions of tooth #21 and interpreparation distance of the #14-16 segment. In general, the technique with isolated acrylic copings (T2) produced casts with larger cervical misfit. The method for bonding the acrylic copings, by acrylic or metal cylinders, had no effect on the accuracy of the casts.
22

Comparación in vitro de la adaptación marginal de coronas unitarias de porcelana vitrocerámica elaboradas con tres sistemas de procesado / In vitro comparison of the marginal adaptation of ceramic glass porcelain crowns manufactured with three processing systems

Zegarra Cavero-Blumenfeld, Fernanda, Meza Huamán, Katya Valeria 02 December 2020 (has links)
Objetivo: Comparar in vitro la adaptación marginal de coronas unitarias de porcelana vitrocerámica elaboradas con tres sistemas de procesado. Materiales y métodos: El presente estudio fue de tipo experimental in vitro. La muestra estuvo conformada por 69 coronas de porcelana vitrocerámica fabricadas con los sistemas: CAD-CAM, inyección de porcelana y condensación sobre muñón refractario. Para la evaluación de la discrepancia marginal vertical se realizó un registro fotográfico con una cámara digital y un lente macroscópico de 100 milímetros. Las imágenes fueron medidas digitalmente (ImageJ) y se utilizaron 52 puntos aleatorios de discrepancia marginal vertical alrededor de las coronas para obtener el promedio de cada una de ellas. Se utilizó la prueba de Kruskal-Wallis para realizar la comparación entre los grupos de estudio con un nivel de significancia estadística de p<0.05. Resultados: El presente estudio encontró diferencias estadísticamente significativas al comparar los tres sistemas de procesado (<0.001). El sistema CAD-CAM tuvo una discrepancia marginal vertical menor (53 µm) en comparación con el sistema de inyección de porcelana (85 µm) y el de condensación sobre muñón refractario (113 µm). Conclusiones: Se encontraron diferencias estadísticamente significativas entre los tres grupos de estudio. Asimismo, el sistema CAD-CAM tuvo una mayor adaptación marginal en comparación con los otros dos métodos de fabricación. Finalmente, los tres sistemas de confección utilizados tuvieron una discrepancia marginal vertical por debajo del límite establecido por la Asociación Americana de Odontología (<120 µm). / Objective: To compare in vitro the marginal adaptation of ceramic glass porcelain single crowns made with three processing systems. Materials and methods: The present study was experimental in vitro. The sample consisted of 69 glass ceramic porcelain crowns manufactured with the following three systems: CAD-CAM, porcelain injection and powder condensation. For de measurement of the vertical marginal discrepancy, the crowns were photographed using a digital camera with a macroscopic lens of 100 millimeters. The images were imported into image processing software (ImageJ) and 52 points were randomly selected around the crown to measure the vertical marginal discrepancy. For each crown, the 52 measurements were combined into a single average marginal discrepancy. Kruskal-Wallis was used to test differences in the observed marginal discrepancies between the study groups. (p <0.05) Results: This study found statistically significant differences when comparing the three different processing systems (<0.001). The CAD-CAM system had a smaller vertical marginal discrepancy (53 µm) compared to the porcelain injection (85 µm) and the powder condensation techniques (113 µm). Conclusions: Statistically significant differences were found between the three study groups. Also, the CAD-CAM system had a greater marginal adaptation compared to the other two manufacturing techniques. Finally, the three fabrication methods used in this study had a vertical marginal discrepancy within the limit established by the American Dental Association (<120 µm). / Tesis
23

Biokompatibilnost i marginalna adaptacija mineral-trioksid agregata, trikalcijum-silikatnog cementa i amalgama kao materijala za retrogradno zatvaranje kanala korena zuba / Biocompatibility and marginal adaptation of mineral trioxide aggregate, tricalcium silicate cement and dental amalgam as a root end filling materials

Jovanović Lena 25 October 2019 (has links)
<p>Već izvesno vreme u stručnoj literaturi vodi se rasprava o biokompatibilnosti materijala koji se koriste u periapikalnoj hirurgiji. Pored biokompatibilnosti, od materijala za retrogradnu opturaciju kanala korena zuba se očekuje da spreči prodor bakterija iz kanalnog sistema u okolna tkiva. Kvalitetno rubno zaptivanje, odnosno adekvatna marginalna adaptacija su među najznačajnijim faktorima za dugoročan uspeh tretmana. Cilj ovog istraživanja je bio ispitati biokompatibilnost i utvrditi da li postoji razlika u biokompatibilnosti između mineral-trioksid agregata, trikalcijum-silikatnog cementa i amalgama na osnovu tri standadna testa citotoksičnosti, kao i utvrditi marginalnu adaptaciju ispitivanih materijala za retrogradno zatvaranje kanala korena zuba. Materijali i metode: Eksperimentalni deo istraživanja je podeljen na dva dela. U prvom delu istraživanja je vr&scaron;eno ispitivanje biokompatibilnosti materijala, dok je u drugom delu vr&scaron;eno ispitivanje marginalne adaptacije na osnovu mikrofotografija dobijenih skening elektronskim mikroskopom. Ispitivanje biokompatibilnosti je izvr&scaron;eno na dve ćelijske linije, liniji mi&scaron;jih fibroblasta (L929) i liniji humanih fibroblasta (MRC-5). U eksperimentima su kori&scaron;ćene samo žive (vijabilne) ćelije. Broj ćelija i njihova vijabilnost je određena testom odbacivanja boje sa 0,1% tripan plavim. Vijabilnost ćelija kori&scaron;ćenih u eksperimentu je bila veća od 90%. Biokompatibilnost sve tri vrste materijala je ispitana na osnovu standardnih testova biokompatibilnosti: DET test, MTT test, Agar difuzioni test. Ispitivanje marginalne adaptacije je sprovedeno na 90 ekstrahovanih jednokorenih zuba interkaninog sektora gornje vilice sa intaktnom pulpom, zavr&scaron;enim rastom korena, bez frakture i resorpcije korena zuba. Izvr&scaron;ena je endodontska obrada svih zuba i nakon toga su zubi ostavljeni u vlažnoj sredini na 48h, da bi se sprečile frakture prilikom sečenja. Nakon mehaničko medikamentozne obrade i opturacije kanala korena zuba je vr&scaron;ena resekcija vrha korena zuba 3mm, a nakon toga su svi zubi preparisani do dubine od 3 mm unutar kanala, ultrazvučnim nastavcima (EMS, miniMaster Piezon scaler). Zubi su naizmenično podeljeni u 3 grupe (30 zuba po grupi). Prvu grupu čine zubi kojima je apikalni kavitet biti ispunjen amalgamom, u drugoj grupi, apikalni kavitet je ispunjen MTA, a u trećoj trikalcijum-silikatnim cementom. Nakon retrogradne opturacije, zubi su ostavljeni u vlažnoj sredini 48h, do potpunog vezivanja ispitivanih materijala. Nakon vezivanja ispitivanih materijala, zubi su sečeni longitudinalno, finom dijamantskom &scaron;ajbnom. Marginalna adaptacija ispitivanih materijala je procenjena skening elektronskim mikroskopom (SEM). Pripremljeni uzorci su posmatrani pod uvećanjima 30x, 40x, 80x i 100x. Uvećanje 30x je rađeno radi prikaza celokoupnog retrogradnog punjenja na jednom snimku, tj. spoja materijal-zub. Nakon toga je napravljeno vi&scaron;e uzastopnih snimaka sauvećanjem 80x do pune dužine materijala. Na taj način je utvrđeno postojanje i izvr&scaron;eno merenje marginalne pukotine u mikrometrima. Merenja ukupne dužine marginalne pukotine u mikrometrima u 5 tačaka sa obe strane preparata su vr&scaron;ena u softverskoj aplikaciji Image J software (National Institutes of Health, Bethesda, USA). Tačke su izabrane tako da tačka 1a i tačka 5a predstavljaju gornju i donju ivicu preparata. Tačka 3a predstavlja sredinu rastojanja između tačke 1a i tačke 5a. Tačka 2a i tačka 4a predstavljaju sredinu razmaka između tačke 1a i 3a, odnosno 3a i a5. Tačke 1b-5b su naspramne tačke. Rezultati biokompatibilnosti ukazuju na visok stepen ćelijske kompatibilnosti svih ispitivanih materijala. Međutim, DET testomnije utvrđena statistički značajna razlika u citotoksičnosti između istovetnih ispitivanih materijala u obe ćelijske linije, niti između sva tri ispitivana materijala u obe ćelijske kulture.Poređenjem rezultata MTT testa nakon 24h i 48h, kao i nakon 48h i 72h uočava se da su dobijene srednje vrednosti indeksa citotoksičnosti kod sva tri ispitivana materijala i na obe ćelijske linije manje nakon 48h, odnosno nakon 72h, &scaron;to ukazuje na oporavak ćelijskog metabolizma. Poređenjem rezultata nakon 24h i nakon 72h, uočava se znatno veći pad vrednosti indeksa citotoksičnosti nakon 72h kod sva tri ispitivana materijala i na obe ćelijske linije. U kulturi ćelija MRC5, kod sva tri ispitivana materijala postoji statistički značajna razlika između indeksa citotoksičnosti izmerenog nakon 24h i nakon 72h, kao i u kulturi ćelija L929. Agar difuzionim testom nije uočena dekolorizacija, niti liza ćelija ispod ispitivanih materijala. Ćelijski odgovor je 0/0 &scaron;to ukazuje da ovim testom nije utvrđeno postojanje citotoksičnog efekta ispitivanih materijala na ćelijske linije L929 i MRC-5. Ispitivanje marginalne adaptacije materijala je vr&scaron;eno na osnovu mikrofotografija dobijenih skening elektronskim mikroskopom.. Najpre su testirane razlike na prvoj tački merenja. Rezultati ovog testa pokazuju da postoje značajne razlike između materijala i da amalgam ima značajno vi&scaron;e vrednosti izmerenih pukotina u odnosu na preostala dva materijala, dok se vrednosti za MTA i biodentin međusobno značajno ne razlikuju. Kao jo&scaron; jedna referentna tačka uzeta je tačka merenja 5. I u odnosu na vrednosti u ovoj tački merenja zabeležene su značajne razlike između materijala. Post hoc Mann-Whitney test pokazuje da se amalgam značajno razlikuje od preostala dva materijala, dok nema značajnih razlika između MTA i biodentina. Na osnovu medijane može se videti da amalgam ima niže vrednosi u ovoj tački merenja u odnosu na preostala dva materijala. U tačkama 2-4, kao i u tačkama 1-5 (ukupno), ne postoji statistički značajna razlika u marginalnoj adaptaciji ispitivanih materijala. Rezultati biokompatibilnosti ukazuju na visok stepen ćelijske kompatibilnosti svih ispitivanih materijala. Rezultati sva tri testa pokazuju da ne postoji statistički značajna razlika u citotoksičnosti između ispitivanih materijala. MTT test pokazuje da u obe ćelijske kulture, kod istovetnih ispitivanih materijala postoji statistički značajna razlika između indeksa citotoksičnosti izmerenog nakon 24h i nakon 72h. Rezultati ispitivanja marginalne adaptacije pokazuju da u tački 1 najgore zaptiva amalgam, dok izmedju MTA i biodentina nema razlike. U tački 5 najbolje zaptiva amalgam.</p> / <p>Biocompatibility of materials, deployed in periapical surgery, has been a subject of debate in referential literature for some time now. Apart from biocompabillity, root end filling materials are expected to prevent bacteria from entering the surrounding tissue from canal system. The most important factors for successful long term treatment include marginal seal, i.e. adequate marginal adaptation. The aim of this research was to examine biocompatibility and establish the potential difference in biocompatibility between mineral trioxide aggregate, tricalcium silicate cement and dental amalgam according to three cytotoxicity tests, but also to corroborate marginal adaptation of the materials in question for retrograde seal of a root canal. Materials and methods: The experimental part of the research is divided in two parts. In the first part of the research biocompatibility of the materials was examined, while the examination of the marginal adaptation based on the micro images from scanning electron microscope was conducted in the second part. The examination of biocompatibility was executed on two cell lines, mouse fibroblast cell line (L929) and human cell line (MRC-5).Biocompatibility of all three types of material was examined based on three standard biocompatibility tests: DET test, MTT test, Agar diffusion test.The examination of marginal adaptation was carried out on 90 single-rooted tooth extractied human teeth of the intercanine sector of maxilla with intact pulp, mature apices, without root fractures or resorption. All teeth were endodontically treated. After the extirpation, irrigation and opturation, the resection of 3mm of root apex and retrograde preparation with ultrasonic instruments up to 3 mm depth inside the canal was done. Teeth were divided in three groups alternately. The First group include teeth which apical cavitation was filled with amalgam, in the Second group apical cavitation was filled with MTA, and in the Third group with tricalcium silicate cement. After the complete setting of the materials, teeth were cut in longitudinal manner, with fine, diamond tool. Marginal adaptation of the materials was assessed through scanning electron microscope (SEM). Software application Image J software was deployed to measure the total length of marginal fissure in micrometers in 5 pointson both sides of the preparation . The results of biocompatibility indicate high degree of cell compatibility of all tested materials. DET test did not assert any statistically significant difference in cytotoxicity between the same tested materials in both cell lines, nor between all three tested materials in both cell cultures. Comparing the results of MTT test after 24h and 48h, and 48h and 72h, it is noted that middle value of cytotoxicity index with all three tested materials and on both cell lines is lower after 48h, and after 72h, indicating the recovery of cell metabolism. In both cell cultures, with all three tested materials there is statistically significant difference between measured cytotoxicity indices after 24h and after 72h. Agar diffusion test did not show decolorization, nor cell lysis underneath the tested materials, which means that cytotoxic effect was not asserted on cell lines L929 i MRC-5. The examination of marginal adaptation was conducted according to micro images gained by scanning electron microscope. The results in the measure point 1 indicate there are significant differences between materials, and amalgam has significantly higher values of the measured fissures in relation to remaining two materials, whereas values for MTA and biodentine do not differ significantly. In measure point 5 significant differences were noted. Post hoc Mann-Whitney test shows that amalgam has lower values of the tested fissures in this measure point in relation to two other materials, while there were no significant differences between MTA i biodentine. In points 2-4, as well as points 1-5 (in total), there were no statistically significant differences in marginal adaptation of the examined materials. The results of all three tests show that there is no statistically significant difference in cytotoxicity between examined materials. MTT test shows that there is, in both cell cultures, with the same examined materials , statistically significant difference between cytotoxicity indices measured after 24h and after 72h. The results of the examination of marginal adaptation show that in point 1 amalgam has the worst seal, whereas between MTA and biodentine there is no difference. In point 5 amalgam has the best seal.</p>

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