Indiana University-Purdue University Indianapolis (IUPUI) / Background: Interim restoration for a lost anterior tooth is often needed for temporary esthetic and functional purposes. Materials for interim restorations usually have less strength than ceramic or gold and can suffer from fracture. Several approaches have been proposed to reinforce interim restorations, among which fiber reinforcement has been regarded as one of the most effective methods. However, some studies have found that the limitation of this method is the poor polymerization between the fibers and the composite resin, which can cause debonding and failure. 64 Purpose: The purpose of this study was to investigate the effects of different polymerization methods as well as fiber types on the mechanical behavior of fiberreinforced composite resin. Material and Methods: A 0.2-mm thick fiber layer from strip fibers or mesh fibers embedded in uncured monomers w as fabricated with polymerization (two-step method) or without polymerization (one-step method), on top of which a 1.8-mm composite layer was added to make a bar-shape sample, followed by a final polymerization. Seventy-five specimens were fabricated and divided into one control group and four experimental groups (n=15), according to the type of glass fiber (strip or mesh) and polymerization methods (one-step or two-step). Specimens were tested for flexural strength, flexural modulus, and microhardness. The failure modes of specimens were observed by scanning electron microscopy (SEM). Results: The fiber types showed significant effect on the flexural strength of test specimens (F = 469.48; p < 0.05), but the polymerization methods had no significant effect (F = 0.05; p = 0.82). The interaction between these two variables was not significant (F = 1.73; p = 0.19). In addition, both fiber types and polymerization steps affected the flexural modulus of test specimens (F = 9.71; p < 0.05 for fiber type, and F = 12.17; p < 0.05 for polymerization method). However, the interaction between these two variables was not significant (F = 0.40; p = 0.53). Both fiber types and polymerization steps affected the Knoop hardness number of test specimens (F = 5.73; p < 0.05 for polymerization method. and F = 349.99; p < 0.05 for fiber type) and the interaction between these two variables was also significant (F = 5.73; p < 0.05). SEM images revealed the failure mode tended to become repairable while fiber reinforcement was 65 existed. However, different polymerization methods did not change the failure mode. Conclusion: The strip fibers showed better mechanical behavior than mesh fibers and were suggested for use in composite resin reinforcement. However, different polymerization methods did not have significant effect on the strength and the failure mode of fiber-reinforced composite

Indiana University-Purdue University Indianapolis (IUPUI) / Background: New glass ceramics and Computer-Aided Design/Computer Assisted Manufacture (CAD/CAM) have become common aspects of modern dentistry. The use of posterior ceramic crowns with a high level of esthetics, fabricated using the CAD/CAM technology is a current treatment modality. Several materials have been used to fabricate these crowns, including lithium disilicate glass-ceramics, which have not been fully investigated in the literature. Objective: to investigate the load to fracture of lithium disilicate glass ceramic posterior crowns fabricated by CAD/CAM technology with different material thicknesses adhesively cemented on epoxy resin. Methods: Four groups of different ceramic thicknesses (0.5 mm, 1 mm, 1.5 mm, and 2 mm) were fabricated by milling CAD/CAM lithium disilicate IPS emax CAD blocks. A total of 68 posterior crowns were surface treated and luted with a resin adhesive cement on an epoxy resin model. Samples were fatigued then loaded to fracture using a universal testing machine to test the fracture strength. Statistical comparisons between various crown thicknesses were performed using one-way ANOVA followed by Fisher's Protected Least Significant Differences. Results: There was a significant difference in the load-to-fracture (N) value for all comparisons of the four thickness groups (p < 0.0001), except 2 mm vs. 1.5 mm (p = 0.325). The mean load-to-fracture (N) was significantly higher for 2 mm than for 1 mm or 0.5 mm. Additionally, the mean load-to-fracture was significantly higher for 1.5 mm than for 1 mm or 0.5 mm. Furthermore, the mean load-to-fracture was significantly higher for 1 mm than for 0.5 mm. Conclusion: Within the limitation of this study, it is advisable for clinical applications to consider a crown thickness of 1.5 mm or greater of milled lithium disilicate for posterior single teeth.

Indiana University-Purdue University Indianapolis (IUPUI) / Background: Since the introduction of glass ionomer cements (GICs) in the 1970s, many attempts have been made to improve them and expand their application in restorative dentistry. Recently, GC America introduced a new glass ionomer restorative system called EQUIA. The manufacturer claims that this material has improved wear resistance by coating the surface of high-strength GIC with a nano-filled resin coating. Objective: The objective of this study was to measure the wear resistance and hardness of EQUIA and to compare it to other current restorative materials. Materials and Methods: Four different materials were used in this study: EQUIA, Fuji IX GP Extra, Fuji II LC and Z-100. Six specimens of each material were made and then tested in a toothbrush abrasion machine for 20,400 cycles, after which the amount of volume loss was calculated. Eight specimens of each material were made and tested in a three-body Alabama wear testing machine under a load of 75 N for 400,000 cycles. Four surface profiles were obtained from each specimen and volume loss was calculated using computer software. Five specimens of each material were made and Knoop microhardness was determined by using the mean of the three values from the top surface of the specimen. Results of each test were collected and compared with the other materials using one-way analysis of variance (ANOVA) at a significance level of 0.05. Results: Wear-resistance results showed that EQUIA has wear-resistance values comparable to composite resin and higher values than those for the high-strength GIC. The results also showed that Fuji II LC had the highest wear among all tested materials. Microhardness results showed that EQUIA has significantly lower microhardness than Fuji IX GP Extra and Z-100. Conclusion: Based on the results of the present study, it can be concluded that coating the surface of glass ionomer restorations with a nano-filled resin coat results in increasing the wear resistance and decreasing the microhardness of the material. Within the limitations of this study, EQUIA has comparable wear resistance to composite resin.

Indiana University-Purdue University Indianapolis (IUPUI) / THE EFFECT OF FULL-CONTOUR Y-TZP CERAMIC SURFACE ROUGHNESS ON THE WEAR OF BOVINE ENAMEL AND SYNTHETIC HYDROXYAPATITE: AN IN-VITRO STUDY by Alaa Hussein Aref Sabrah Indiana University School of Dentistry Indianapolis, Indiana Full-contour yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) restorations have been advocated recently in clinical situations where occlusal/palatal space is limited, or to withstand parafunctional activities. The objectives of this in-vitro study were to investigate the effects of different polishing techniques on the surface roughness of Y-TZP (Ardent Dental, Inc.) and to investigate the effects of different polishing techniques on the wear behavior of synthetic hydroxyapatite (HA) and bovine enamel. An in-vitro study was conducted by fabrication of 48 Y-TZP sliders (diameter = 2 mm × 1.5 mm in height) using CAD/CAM technique; then the samples were embedded in acrylic resin using brass holders. Samples were then randomly allocated into four groups according to the finishing/polishing procedure: G1-as-machined (n = 8), G2- glazed (n = 16), G3-diamond bur-finishing (Brasseler, USA) (n = 8) and G4- G3+OptraFine polishing kit (Ivoclar-Vivadent) (n = 16). Thirty-two sintered HA disks (diameter = 11 mm × 2.9 mm in height) and 16 bovine enamel samples with a minimum surface area of 64 mm2 were mounted in brass holders. Baseline surface roughness (Ra and Rq, in μm) were recorded using a non-contact profilometer (Proscan 2000) for all the samples. A two-body pin-on-disk wear test was performed for 25,000 cycles at 1.2 Hz in which the four zirconia groups were tested against HA, and only G2-glazed and G4- G3+OptraFine polishing kit (Ivoclar-Vivadent) were tested against bovine enamel. Vertical substance loss (μm) and volume loss (mm3) of HA were measured (Proscan). Zirconia height loss was measured using a digital micrometer. One-way ANOVA was used for statistical analysis. The results indicated that surface roughness measurements showed significant differences among the surface treatments with G1 (Ra = 0.84, Rq = 1.13 μm) and G3 (Ra = 0.89, Rq = 1.2 μm) being the roughest, and G2 (Ra = 0.42, Rq = 0.63 μm) the smoothest. The glazed group showed the highest vertical loss (35.39 μm) suggesting wear of the glaze layer, while the polished group showed the least vertical loss (6.61 μm). HA antagonist volume loss and vertical height loss for groups (G1, G2 and G3) were similar, while polished group (1.3 mm3, 14.7 μm) showed significant lower (p = 0.0001) values. Antagonist height loss and antagonist volume loss were significantly higher for bovine antagonist than for HA antagonist (197.6 μm/116.2 μm, and 28.5 mm3/17.7 mm3 for bovine against glazed/polished zirconia sliders, respectively) (p < 0.0001). From the results it can be concluded that glazed zirconia provided an initially smooth surface, but a significant increased antagonist wear compared with the polished surface was seen. Bovine enamel showed higher wear compared with HA, which suggested that more studies should be performed to validate the use of bovine enamel as a substitute for human enamel in wear studies.

O objetivo desta tese foi identificar, analisar e sintetizar evidências científicas quanto à eficácia do Tratamento Convencional (TC) e do Tratamento Restaurador Atraumático (ART) em molares decíduos considerando os parâmetros de longevidade, custo, aceitabilidade e desfechos reportados pelo paciente. Este volume apresenta um compilado de uma revisão sistemática e dois ensaios clínicos randomizados orientados pelas recomendações PRISMA, CONSORT-PRO e CHEERS. Realizamos uma revisão sistemática, cuja pesquisa bibliográfica buscou por desfechos reportados pelo paciente (PROs) em relação a tratamentos restauradores na dentição decídua em estudos prospectivos indexados no PubMed, Scopus e OpenGrey até fevereiro de 2018. Meta-análise de Comparação de Tratamento Misto foi realizada considerando os resultados dos estudos revisados. Devido à incompatibilidade de dados, apenas dor, ansiedade e a qualidade de vida relacionada à saúde bucal (QVRSB) foram analisados estatisticamente. Adicionalmente, delineamos um ensaio clínico de não inferioridade randomizado por cluster cujo desfecho primário foi a longevidade do TC e do ART em cavidadades oclusais e oclusoproximais de molares decíduos após 24 meses de acompanhamento. Como desfechos secundários, foram avaliados a aceitabilidade, representada pelo desconforto auto relatado e cooperação dos participantes, e a custo-eficácia. Crianças entre 3 e 6 anos apresentando pelo menos uma cavidade oclusal ou oclusoproximal em molares decíduos foram randomizadas entre os grupos convencional (TC) com resina composta sob isolamento absoluto após anestesia local ou o ART. Em ambos os grupos foi realizada remoção parcial de tecido cariado. O estudo foi desenvolvido em um trailer odontológico localizado no interior de uma escola municipal de Barueri/SP. Imediatamente após cada sessão restauradora, foi mensurado o desconforto auto relatado pelo participante e o comportamento pelo operador através da Escala Facial de Wong-Baker e escala de 5 pontos, respectivamente. As restaurações oclusais e oclusoproximais foram avaliadas após 6, 12, 18 e 24 meses segundo o critério de Frencken et al. 1998 e de Roeleveld et al. 2006. Os custos profissional e do procedimento, subdividido em custos variável e do material de consumo, foram considerados para estimar o custo incremental dos tratamentos. Regressão de Poisson em análise de multinível, Regressão de Cox com fragilidade compartilhada e regressão de Bootstrap foram utilizadas para testar o desconforto e cooperação, a sobrevida e o custo entre os tratamentos e outras variáveis independentes. O nível de significância foi ajustado em 5%. Tratamentos restauradores que utilizam agentes quimicomecânicos ou apenas instrumentos manuais para remoção de tecido cariado, como o ART, resultaram em menores índices de ansiedade e menor tendência em provocar dor em crianças do que tratamentos que utilizam instrumentos rotatórios e/ou anestesia. A QVRSB não foi influenciada pelos tratamentos restauradores nem diferiu entre os grupos. Por outro lado, o TC e o ART apresentaram baixa taxa de desconforto e alto índice de cooperação sem diferença estatisticamente significante entre eles. Ambos os tratamentos apresentaram sobrevida semelhante nas cavidades oclusais após 24 meses de acompanhamento, porém o custo do ART foi menor, demonstrando ser a opção mais custo-eficaz. Em relação às restaurações oclusoproximais, apesar do desempenho do TC ser superior ao ART, ele apresentou maior custo. Pode-se concluir que ansiedade e dor estão diretamente relacionados com tratamentos restauradores mais invasivos. Por outro lado, o TC e o ART apresentaram desconforto, cooperação e custo-eficácia semelhantes no tratamento de molares decíduos. Palavras-chave: Restauração dentária permanente. Dente decíduo. Longevidade. Custos e análises de custo. Medidas de resultados relatados pelo paciente. Ensaio clínico. Revisão. Odontopediatria. / The aim of this thesis was to identify, analyze and synthesize scientific evidences regarding the efficacy of conventional treatment (CT) and Atraumatic Restorative Treatment (ART) in primary molars considering the parameters of longevity, cost, acceptability and patient reported outcomes. This volume presents a compilation of a systematic review and two randomized clinical trials guided by the PRISMA, CONSORT-PRO and CHEERS recommendations. We performed a systematic review whose literature search included outcomes reported by the pediatric patient (PROs) related to restorative treatments in the primary dentition in prospective studies indexed in PubMed, Scopus and OpenGrey until February 2018. Mixed Treatment Comparison analysis was performed considering the results of the reviewed studies. Due to data incompatibility, only pain, anxiety and oral health related to quality of life (OHRQoL) were analyzed statistically. Additionally, we designed a cluster randomized non-inferiority clinical trial whose primary outcome was the longevity of occlusal and occlusoproximal ART and TC restorations in primary molars after 24 months of follow-up. As secondary outcomes, acceptability, represented by self-reported discomfort and participant cooperation, and cost-efficacy were assessed. Children between 3 and 6 years old presenting at least one occlusal or occlusoproximal cavity in primary molars were randomized between the conventional group (TC) with composite resin under rubber dam isolation after local anesthesia or ART. Partial removal of carious tissue was performed in both groups. The study was carried out in a dental trailer located inside a municipal school in Barueri/SP. Immediately after each restorative session, self-reported discomfort and participant cooperation were measure through the Wong-Baker Facial Scale and a 5-point scale, respectively. The occlusal and occlusoproximal restorations were evaluated after 6, 12, 18 and 24 months according to the criteria of Frencken et al. 1998 and Roeleveld et al. 2006. The professional and procedural costs, subdivided into variable and material of consumption\' costs, were considered to estimate treatments\' incremental cost. Poisson regression in multilevel analysis, Cox regression with shared fragility and Bootstrap regression were used to test discomfort and cooperation, survival and cost between treatments and among others independent variables. The level of significance was set at 5%. Restorative treatments using chemomechanical agents or only manual instruments, such as ART, were related to lower anxiety rates and less tendency to provoke pain in children compared to treatments using rotary instruments and/or anesthesia. OHRQoL was not influenced by restorative treatments nor differed between groups. On the other hand, CT and ART presented low rate of discomfort and a high cooperation with no statistically significant difference between them. Both treatments presented similar survival rates in occlusal restorations after 24 months of follow-up, but the ART cost was lower, proving to be the most cost-effective option. Regarding occlusoproximal restorations, although CT performance was superior to ART, it presented a higher cost. It can be concluded that anxiety and pain are directly related to more invasive restorative treatments. Differently, CT and ART have similar discomfort, cooperation and cost-efficacy in the treatment of primary molars.

Estudamos 62 pacientes, que com teste ergométrico positivo, manifestaram angina estável e estavam sob controle farmacológico. Todos apresentavam cinecoronariografia mostrando obstrução >70% em pelo menos uma das principais artérias coronárias. Objetivamos avaliar parâmetros eletrocardiográficos e de pressão arterial, durante procedimento odontológico restaurador sob anestesia local com e sem vasoconstritor em presença de doença arterial coronária. As idades variaram de 39 a 80, média de 58,7±8,8 anos, sendo 51 (82,3%) homens. Trinta pacientes foram randomizados para receber anestesia local com solução de lidocaína a 2% com adrenalina 1:100.000 e os demais para lidocaína a 2% sem vasoconstritor. Todos os pacientes foram submetidos à monitorização ambulatorial da pressão arterial (MAPA) e eletrocardiografia dinâmica por 24 horas, iniciados 2 horas antes do procedimento odontológico. Consideramos 3 períodos de registro: (1) basal - os 60 minutos que antecederam ao procedimento odontológico; (2) procedimento - desde o início da anestesia até o final do procedimento odontológico restaurador; (3) subseqüente completar das 24 horas. A análise de variância com medidas repetidas mostrou que houve elevação significativa da pressão arterial sistólica e diastólica do período basal para o procedimento nos dois grupos estudados (aproximadamente 14mmHg e 5 a 7mmHg) respectivamente, quando analisados separadamente e quando confrontados não apresentaram diferença de comportamento entre si. A freqüência cardíaca não se alterou nos dois grupos estudados. Depressão do segmento ST >1mm ocorreu em 10 (17,9%) pacientes; todos os eventos ocorreram no mínimo 2 horas após o término do procedimento odontológico. Extra - sístoles supra-ventriculares e/ou extra-sístoles ventriculares em número maior do que 10/hora estiveram presentes em 17 (30,4%) pacientes durante as 24 horas e durante o período do procedimento em 7 (12,5%), sendo 4 (13,8%) do grupo que recebeu anestesia sem adrenalina e 3 (11,1%) do grupo que recebeu anestesia com adrenalina e o teste Exato de Fisher não mostrou diferença entre os grupos. Concluímos que não houve diferença em relação ao comportamento de pressão arterial, freqüência cardíaca, evidência de isquemia e arritmias entre os grupos. O uso associado de vasoconstritor mostrou-se, portanto, seguro dentro dos limites do estudo. / We enrolled 62 patients with positive exercise stress test who presented with stable angina and were receiving drug therapy. All had a coronary angiography screening showing >70% obstruction in at least one of the main coronary arteries. The study aimed to compare electrocardiographic and blood pressure parameters during restorative dentistry procedure under local anesthesia, both with and without vasoconstrictor, in the presence of coronary artery disease. Ages ranged from 39 to 80, (mean ± SD) 58.7±8.8 years, 51 (82.3%) of them were male. Thirty patients were randomly assigned to receive 2% lidocaine local anesthesia with 1:100,000 epinephrine, the others receiving 2% lidocaine without vasoconstrictor. All the patients underwent ambulatory blood pressure and 24-hour Holter monitoring, beginning two hours ahead of the dental procedure. Recording were made during (1) baseline - 60-minute period before dental procedure began; (2) procedure - from beginning of anesthesia until the end of the procedure; and (3) subsequent 24-hour period. Analysis of variance with repeat measures showed significant diastolic and systolic blood pressure increases from baseline to the period of the procedure, in the two study groups (approximately 14 mm Hg, and 5 to 7 mm Hg, respectively); both in a separate analysis and in a comparative analysis no significant difference between them could be confirmed. Heart rate did not change in neither of the two groups. ST-segment >1 mm depression was detected in 10 (17.9%) patients; all these events occurred at least two hours after the end of the dentistry procedure. Premature supraventricular systoles and/or premature ventricular systoles in a greater number than 10/hour were seen in 17 (30.4%) patients in the 24-hours period after the procedure; during the procedure they occurred in 7 (12.5%) patients, of whom 4 (13.8%) were in the group without, and 3 (11.1%) in the group with vasoconstrictor. The Fisher\'s exact test revealed no difference between the groups. We concluded that there was no difference of blood pressure, heart rate, evidence of ischemia or arrhythmia episodes between the groups. Thus, the associated use of vasoconstrictor proved to be safe within the limits of this study

<p>Uvod. Usled kompromitovanja strukturnog integriteta, rekonstruktivne procedure na endodontski lečenim zubima moraju se veoma pažljivo isplanirati, pogotovo u specifičnoj grupi zuba kao &scaron;to su premolari. U stomatolo&scaron;koj naučnoj i stručnoj javnosti ne postoji usagla&scaron;en stav o tome koja endodontska instrumentacija i rekonstruktivna procedura primenjena u slučajevima ekstenzivnog gubitka zubne supstance predstavlja metodu izbora sa biomehaničkog aspekta. U okviru prezentovane doktorske disertacije ispitivan je uticaj varijacija u endodontskoj instrumentaciji i restaurativnim procedurama na promene naponskih stanja u zubnim tkivima i rekonstruktivnim materijalima kod premolara sa ekstenzivnim gubitkom zubne strukture. Metode. Osnovni 3D model je kreiran pomoću CT snimaka zdravog drugog gornjeg premolara u SolidWorks programu za modelovanje. Kreirano je 135 različitih modela, u kojima su metodom konačnih elemenata proračunati fon Mizesovi naponi u položaju maksimalne interkuspidacije pod dejstvom sile od 150 N. Statistička analiza je izvr&scaron;ena koristeći Op&scaron;ti linearni model. Rezultati. Indirektne zubne rekonstrukcije imaju povoljniji uticaj na naponska stanja u zubnim tkivima. Ukoliko se koristi direktna restauracija, povoljniji su naponi u dentinu i gleđi ukoliko se redukuje palatinalna kvržca. Upotreba kočića uz ispun snižava napone u zubnim tkivima samo u slučaju MOD kaviteta. Naponi u dentinu su niži pri apikalnom terminusu 0,5 mm i instrumentaciji instrumentima manje veličine (kod modela sa kočićem i indirektnim nadoknadama). Uglavnom procedure koje su povoljne za napone u dentinu, nepovoljne su za napone u zubnoj nadoknadi i obratno. Zaključci. Kod opsežnih MOD kaviteta a samo ukoliko se ne redukuje visina palatinalne kvržice, preporučuje se upotreba kompozitnog kočića. Smanjenje povr&scaron;ine zubnih tkiva u kojima su naponi visoki (iako su najvi&scaron;e vrednosti napona slične), moglo bi da utiče na dugotrajnost endodontski lečenih i rekonstruisanih zuba. Krući rekonstruktivni materijali povoljnije utiču na napone u zubnim tkivima biomehanički kompromitovanih endodontski lečenih zuba. Čini se da je optimalnije, u rekonstruktivnim re&scaron;enjima koja podrazumevaju upotrebu kočića, postaviti apikalni terminus bliže vrhu korena i koristiti instrumente srednje &scaron;irine.</p> / <p>Background. Restoration of an endodontically treated premolar with a wide and deep mesial-occlusal-distal (MOD) cavity is often complex due to biomechanical weakening of the tooth. There are no definitive recommendations on the optimal restoration in these cases. The aim of this study was to determine the effects of different endodontic and restorative procedures on von Mises stress values and distribution in dental tissues and restorative materials using finite element analysis (FEA). Methods. Based on CT scans of an second upper premolar, extracted for orthodontic reasons, 135 3D endodontically treated tooth models were created. Each model was subjected to a summary force of 150 N on the occlusal surface simulating the normal biting pattern and maximal von Mises stresses were calculated. Results. MODP cavity design seems to reduce von Mises stress values in dental tissues and P seems to transfer some of the stresses from dental tissues to the composite filling in the MOD cavity when direct restorations are used. Indirect restorations caused lower stresses within dentin. Apical terminus of 0.5 mm induces lower, while the terminus of 1.5 mm induces the highest stresses in dentin in models restored with direct composite and post. It seems that from the aspect of the tooth tissue, it is more recommended to use smaller endodontic instruments sizes. Conclusions. Stiffer restorative materials cause lower stresses in dentin of an endodontically treated structurally weakened tooth, and if a direct restoration is to be used, palatal cuspal reduction could be beneficial for the longevity of the tooth and the restoration. Further, in a wide and deep MOD cavity, without cuspal reduction, the use of a FRC post is recommended in order to reduce the stresses in the enamel and dentin. Moreover, it seems that it is beneficial for the stresses in the tooth tissue to place the apical terminus closer to the root apex as well as to use smaller size endodontic instruments.</p>

<p>Gubitak tvrdih zubnih struktura usled karijesne lezije, traume ili ekstenzivne preparacije dovodi do smanjenja otpornosti preostalih zubnih struktura na dejstvo sila prilikom žvakanja. Osnovni zadatak restaurativne procedure je da se ponovo uspostavi anatomo-morfolo&scaron;ka funkcija zuba i da se preostale zdrave zubne strukture za&scaron;tite od nepovoljnog odgovora na dejstvo sila. Cilj doktorske disertacije bio je da se ispita uticaj različitih restaurativnih procedura na biomehaničke karakteristike premolara sa ekstenzivnim kavitetima. Materijal i metode: Trodimenzionalni model intaktnog drugog gornjeg premolara kreiran je u SolidWorks računarskom programu, na osnovu snimaka ekstrahovanog zuba primenom vi&scaron;eslojnog spiralnog kompjuterizovanog tomografa. Na osnovu ovog modela potom je kreirano ukupno 48 modela, koji su podeljeni u dve grupe: modeli vitalnog premolara sa MOD kavitetom (I grupa) i modeli premolara sa endodontski lečenim kanalom korena sa MOD kavitetom (II grupa). U svakoj grupi ispitivan je uticaj 4 vrste restaurativnog materijala (direktan kompozitni ispun, direktan kompozitni ispun sa smolom modifikovanim glas-jonomer cementom u vidu podloge, indirektan kompozitni ispun, keramički ispun), 3 dizajna preparacije kaviteta (bez skraćivanja kvržica, sa skraćivanjem palatinalne kvržice 2mm, sa skraćivanjem palatinalne i bukalne kvržice 2mm) i 2 &scaron;irine istmusa (1/2 i 2/3 interkuspalnog razmaka). Primenom metode konačnih elemenata proračunate su vrednosti von Mises napona u zubnim strukturama i ispunu za sve modele pri dejstvu statičke sile od 200N. Rezultati: Dizajn preparacije kaviteta je pokazao najveći uticaj na vrednosti von Mises napona u zubnim strukturama. Pri tome, postupak skraćivanja palatinalne, kao i obe kvržice, doprineo je smanjenju vrednosti von Mises napona u gleđi na modelima obe grupe; dok je postupak skraćivanja bukalne i palatinalne kvržice doprineo smanjenju vrednosti von Mises napona u dentinu na modelima vitalnog premolara. U obe grupe, vrsta restaurativnog materijala pokazala je uticaj na vrednosti von Mises napona u gleđi, pri čemu je keramički ispun doveo do pojave napona značajno manjih vrednosti u odnosu na direktan i indirektan kompozitni ispun.Vrsta restaurativnog materijala je uticala i na vrednosti von Mises napona u dentinu, ali samo na modelima vitalnog premolara; pri tome su indirektni kompozitni i keramički ispun podjednako doprineli pojavi napona manjih vrednosti. &Scaron;irina istmusa je uticala na vrednosti von Mises napona u gleđi i dentinu na modelima vitalnog premolara. &Scaron;irina istmusa 1/2 interkuspalnog razmaka dovela je do pojave napona manjih vrednosti u gleđi, dok je &scaron;irina istmusa 2/3 interkuspalnog razmaka dovela do pojave napona manjih vrednosti u dentinu.</p> / <p>Loss of tooth structure from caries, trauma or extensive preparation decreases fracture resistance of tooth. The main goal of restorative procedure is to rebuild lost structures and to protect remaining tooth structures from unfavorable responses from masticatory forces. Aim of thesis was to investigate the influence of different restorative procedures on biomechanical properties of premolar with extensive cavities. Materials and Methods: Three dimensional model of intact maxillary second premolar, based on computerized tomography scan images of extracted tooth, was designed using SolidWorks software. Using this model, 48 models were designed and divided in two groups: models of vital premolars with MOD cavities (group I), and models of premolars with root canal treatment with MOD cavities (group II). In each group use of four restorative materials (direct composite resin restoration, direct composite resin restoration with resin modified glass-ionomer cement as base, indirect composite resin restoration, ceramic restoration), three cavity preparation designs (without cusp coverage, 2mm palatal cusp coverage, 2mm palatal and buccal cusp coverage) and two isthmus width (1/2 and 2/3 intercuspal width) were simulated. After applying static load of 200N, von Mises stresses in enamel, dentin and restoration were calculated using finite element analysis. Results: Cavity preparation design showed the most significant influence on von Mises stress values in tooth structures. Cusp coverage in general decreased stress values in enamel, while palatal and buccal cusp coverage decreased stress values in dentin only in group I. Restorative material affected stress values in enamel, were ceramic restoration contributed to minimal stress values. In dentin, indirect composite resin and ceramic restoration showed no difference in reducing von Mises stress values, but only for models in group I. Cavity isthmus width had influence on stress values in tooth structures only in group I. 1/2 isthmus width decreased stress values in enamel, while 2/3 isthmus width showed same effect in dentin. Conclusion: In order to provide optimal biomechanical characteristics of tooth structures, premolars with MOD cavity should be restored with ceramic overlay covering both palatal and buccal cusp.</p>

Submitted by ANA FLÁVIA NUNES E REIS null (dra-anaflavia@uol.com.br) on 2016-01-26T19:16:31Z No. of bitstreams: 1 merged (4).pdf: 4937949 bytes, checksum: c052666784bd930ac4748e41040c73bd (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-01-28T13:31:20Z (GMT) No. of bitstreams: 1 reis_afn_me_sjc.pdf: 4937949 bytes, checksum: c052666784bd930ac4748e41040c73bd (MD5) / Made available in DSpace on 2016-01-28T13:31:20Z (GMT). No. of bitstreams: 1 reis_afn_me_sjc.pdf: 4937949 bytes, checksum: c052666784bd930ac4748e41040c73bd (MD5) Previous issue date: 2015-12-15 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi infiltrar sílica em uma cerâmica Y-TZP, avaliar seu efeito na resistência à flexão Biaxial, e na união com a porcelana feldspática. Para a análise da resistência à flexão foram confeccionados 180 discos de zircônia, 120 de 0,5mm e 60 com 1,2mm discos (14 mm de diâmetro). 90 discos foram infiltrados com sílica pelo método sol-gel em temperatura ambiente (n = 30). A espessura do disco foi de 1,2 mm para os espécimes controle (espécime sem porcelana, n = 30). O recobrimento por porcelana feldspática foi de duas espessuras (0,5mm e 1 mm) sobre a zircônia que tinha 0,5 mm. Os espécimes com porcelana foram polidos com lixas de carbeto de silício (SiC) de granulação # 400, 600, 800 e 1200. Obtivemos 6 grupos: dois monolíticos (ZR- Zircônia Monolítica sem infiltração e ZRI- Zircônia Monolítica Infiltrada) (controle) e quatro estratificados: ZRF 1,0 (0,5mm Zircônia coberta com 0,5 mm porcelana), ZRIF 1,0 (0,5 mm Zircônia infiltrada coberta com 0,5 mm de porcelana), ZRF 1,5 (0,5 mm Zircônia infiltrada coberta com 1,0 mm de porcelana) ZRIF 1,5- Zircônia infiltrada (0,5 mm Zircônia infiltrada coberta com 1,0 mm de porcelana). Após o ensaio de flexão biaxial em meio aquoso, foram determinados o módulo de Weibull (m) e resistência característica (σθ). Os fragmentos foram analisados em EDS, MEV, DRX e FTIR. A Dureza (H) e tenacidade a fratura foram analisadas pela nanoindentação, já o módulo elástico (E) por duas técnicas, nanoindentação e por impulso, e para avaliar a adesão entre a zircônia e a porcelana foi aplicado o Teste de Scratch. Foram modeladas 7 condições experimentais e analisados pelo método por elementos finitos. A zircônia monolítica infiltrada mostrou uma estrutura com grãos arredondados envoltos em uma matriz de sílica, e a presença de zircônia cúbica e tetragonal. O DRX revelou a formação de ZrSiO4 nos grupos infiltrados. Os grupos monolíticos apresentaram módulos de Weibull superiores aos dos grupos com porcelana. Com a análise (AEF) não houve diferença entre os grupos com a mesma espessura, já para o grupo recoberto com 0,5 mm de porcelana, os valores de tração e compressão foram maiores. A cerâmica infiltrada apresentou microestrutura diferente, e a adesão da porcelana à zircônia não-infiltrada foi superior à da zircônia infiltrada. / The objective was to infiltrate silica in a Y- TZP ceramics, evaluate its effect on resistance biaxial strenght, and the union with feldspathic porcelain. For the analysis of flexural strength were prepared zirconia discs 180, 120 and 60 of 0.5 mm to 1.2 mm disks (14 mm diameter). 90 discs were infiltrated with silica by the sol-gel method at room temperature (n = 30). The thickness of the disk was 1.2 mm for the samples control (no porcelain specimen, n = 30). The coating was feldspathic porcelain by two thicknesses (0.5 mm and 1 mm) of zirconia, which had 0.5 mm. Specimens with porcelain were polished with sandpaper silicon carbide (SiC) granulation # 400, 600, 800 and 1200. We obtained six groups: two monolithic (Zr-Zirconia Monolithic without infiltration and ZRI- Zirconia monolithic Infiltrated) (control) and four laminated ZRF 1.0 (0.5 mm zirconia covered with 0.5 mm porcelain), ZRIF 1.0 (0.5 mm infiltrated zirconia covered with 0.5 mm of porcelain), ZRF 1.5 (0.5 mm infiltrated zirconia covered with 1.0 mm of porcelain) ZRIF 1,5-infiltrated Zirconia (0.5 mm infiltrated zirconia covered with 1.0 mm of porcelain). After the biaxial bending test in an aqueous medium were determined Weibull modulus (m) and the characteristic strength (σθ). The fragments were analyzed by EDS, SEM, XRD and FTIR. The hardness (H) and fracture toughness were analyzed by nanoindentation, since the elastic modulus (E) by two techniques, nanoindentation and on impulse, and to evaluate the adhesion between the zirconia and porcelain was applied Scratch Test. 7 experimental conditions were modeled and analyzed by the finite element method. The infiltrated zirconia showed a monolithic structure with rounded grain wrapped in a silica matrix, and the presence of cubic and tetragonal zirconia. The XRD showed the formation of ZrSiO4 infiltrates in groups. The monolithic modules Weibull groups showed superior to porcelain groups. With the analysis (FEA) there was no difference between the groups with the same thickness, for now the group covered with 0.5 mm of porcelain, the tensile and compressive values were higher. The infiltrated ceramic showed different microstructure, and the accession of porcelain to non- infiltrated zirconia was higher than the infiltrated zirconia.

Made available in DSpace on 2014-08-20T14:30:20Z (GMT). No. of bitstreams: 1 Tese - Fabio Herrmann.pdf: 2352205 bytes, checksum: a6bcc0f4e7708f23fde2f31a66c02b83 (MD5) Previous issue date: 2006-06-23 / The aim of this study was to evaluate, in vitro, the effect of composite resin restoration techniques, bevel and storage time on the fracture strength, restoration retention and gap formation. For the fracture strength test, standard MOD cavities were prepared in 100 upper premolars, which were divided in two storage times (24 hours and 6 months with 1000 thermocycles), and in each group, sub-groups were randomly formed as follow: group 1 direct composite resin restoration(Filtek Z250 and Adper Single Bond 3M/ESPE) without bevel (butt joint); group 2 beveled direct composite resin restoration; group 3 indirect composite resin inlay (Z250 and Rely X ARC 3M/ESPE) without bevel(butt joint); group 4 beveled indirect composite resin inlay; group 5 sound teeth; group 6 teeth with MOD preparations (no restorations). For the retention test, the incisal edge of 90 lower incisors was sectioned, and divided in the same restorative groups as described above (except group 6). To evaluate gap presence or absence, proximal box cavities were prepared in 24 human third molars, which were restored with direct or indirect composite restorations, with or without bevel, similar to above described and examined under SEM evaluation. Data was statistically analysed by A NOVA, Tukey and t-student tests for fracture strength and retention tests, and Fisher s exact test for gap formation (=0,05). At the 24 hours, beveled restorations exhibited higher fracture strength values than non beveled restorations and most of the tested groups showed resistance similar or superior than sound teeth. After 6 months, the best results were obtained for beveled inlays and the worst values were observed for butt joint direct restorations. In the retention test,beveled restorations had superior performances than non-beveled restorations, in both periods of time. For both tests, a 6-month storage time and thermal cycling produced significant properties decrease in groups 1, 2 and 4 showed. Under SEM examination, no difference was observed among groups after 24 hours. However,after 6 months, beveled restotations remained without gap formation and they had better performance than butt joint restorations. Pearson correlation test showed positive correlation between fracture strength and retention tests. Within the limitations of the study, it was concluded that aging impaired adhesive properties, bevel improved the performance in all tests and generally indirect restorations were not superior to direct restorations. / O objetivo do presente trabalho foi avaliar in vitro o efeito da técnica restauradora, da confecção de bisel e do tempo de armazenamento de restaurações de resina composta sobre a resistência à fratura dental, resistência à fratura de restaurações (resistência adesiva) e formação de fenda marginal. Para o teste de resistência à fratura dental, foram utilizados 100 pré-molares superiores, submetidos a preparos cavitários MOD, divididos em 2 tempos de armazenamento (24 horas e 6 meses com termociclagem 1000 ciclos), subdivididos nos seguintes grupos: grupo 1 restaurados com resina composta direta (Filtek Z250 e Adper Single Bond 3M/ESPE) sem bisel; grupo 2 resina composta direta com bisel; grupo 3 resina composta semi-direta (Z250 e Rely X ARC 3M/ESPE) sem bisel; grupo 4 resina composta semi-direta com bisel; grupo 5 dentes hígidos; e grupo 6 dentes apenas preparados (n=10). Para o teste de resistência à fratura de restaurações, foram utilizados 90 incisivos inferiores, que receberam desgaste do bordo incisal e foram divididos nos mesmos grupos citados acima (exceto o grupo 6). Para a avaliação de presença ou ausência de fenda marginal,foram empregados 24 terceiros molares, que receberam preparos proximais, divididos nos mesmos grupos acima (exceto os grupos 5 e 6). Os dados foram submetidos à análise estatística (=0,05) através dos testes ANOVA, Tukey e t-student para resistência à fratura dental e resistência à fratura de restaurações e teste exato de Fisher para formação de fenda marginal. Os resultados mostraram que, para resistência à fratura dental, no tempo de 24 horas, as restaurações com bisel foram superiores às demais, enquanto as sem bisel não diferiram dos dentes hígidos. Após 6 meses, as restaurações semi-diretas com bisel foram superiores às demais, não diferindo das semi-diretas sem bisel; as restaurações diretas sem bisel foram inferiores às demais. Para resistência à fratura de restaurações, as restaurações com bisel foram superiores às demais para ambos os tempos de armazenamento, e não diferiram dos dentes hígidos em 24 horas. Para os 2 testes citados, os grupos 1, 2 e 4 apresentaram redução significativa do seu desempenho após 6 meses de armazenamento e termociclagem. A avaliação de fenda em esmalte mostrou que em 24 horas não houve diferença entre os grupos. Após 6 meses, as restaurações com bisel continuaram livres de fenda, enquanto as sem bisel apresentaram fenda na maioria dos espécimes. A análise de correlação de Pearson mostrou resultado significativamente positivo para os 2 testes de resistência. Concluiu-se que o tempo de armazenamento e termociclagem foram fatores significativos na redução da performance adesiva; a realização de bisel influenciou de forma positiva na melhora do desempenho das restaurações em todos os testes empregados; as restaurações semi-diretas de resina composta, de modo geral, não foram superiores às diretas.