Submitted by FERNANDA DE OLIVEIRA ABU-IZZE null (fefeizze@hotmail.com) on 2018-03-12T22:56:56Z No. of bitstreams: 1 12.01.18 biblio correção final.pdf: 10328694 bytes, checksum: 640b2d0c989c903e0216bd6a154400e4 (MD5) / Approved for entry into archive by Silvana Alvarez null (silvana@ict.unesp.br) on 2018-03-20T20:51:39Z (GMT) No. of bitstreams: 1 abu_izze_fo_me_sjc.pdf: 10328694 bytes, checksum: 640b2d0c989c903e0216bd6a154400e4 (MD5) / Made available in DSpace on 2018-03-20T20:51:39Z (GMT). No. of bitstreams: 1 abu_izze_fo_me_sjc.pdf: 10328694 bytes, checksum: 640b2d0c989c903e0216bd6a154400e4 (MD5) Previous issue date: 2017-12-01 / A fim de investigar a vida em fadiga, modos de falha e distribuição de tensões de restaurações ultrafinas parciais, tipo tabletop, em diferentes cerâmicas, sessenta preparos padronizados foram confeccionados em resina epóxi G10 e foram cimentadas adesivamente restaurações cerâmicas de silicato de lítio reforçado com zircônia (ZLS, Vita Suprinity- Vita Zahnfabrik), ou restaurações de cerâmica híbrida (PIC, Vita Enamic- Vita Zahnfabrik), em 0,5 ou 1 mm de espessura. O mesmo protocolo de ciclagem foi aplicado para todos os espécimes, que consistiu em 5.000 ciclos a 200 N, seguidos de 450 N ciclos até a fratura dos espécimes ou a suspensão do teste após 1,5 x 106 ciclos. A carga axial foi realizada com uma freqüência de 4 Hz no equipamento Biocycle V2 (Biopdi, São Carlos, SP), com amostras imersas em água. A presença de falhas e/ou fraturas foi verificada a cada 2,5 x 105 ciclos e a análise de sobrevivência foi realizada com o número de ciclos em que cada espécime falhou. Os espécimes foram avaliados usando estereomicroscópio e microscopia eletrônica de varredura (MEV). Após a tabulação de dados, foram realizados Kaplan-Meier e Mantel-Cox (Teste Log Rank), seguindo de comparação múltipla aos pares, todos com nível de significância de 5% e análise de Weibull. Através da análise tridimensional de elementos finitos, a distribuição de tensões máximas principais (TMP) nas tabletop oclusais posteriores foram avaliados comparando diferentes tipos de substrato (G10, esmalte/dentina, esmalte), espessuras e materiais cerâmicos. As restaurações de silicato de lítio reforçadas com zircônia com 0,5 mm de espessura (ZLS.5) apresentaram menor resistência à fadiga em comparação com restaurações cerâmicas híbridas de 1,0mm (PIC1), e ambas foram similares a outras restaurações (PIC.5 e ZLS1); X2 = 11,2; df = 3; p = 0,0107 <0,05). Os grupos ZLS apresentaram defeitos aleatórios que culminaram com a fratura, ao passo que os grupos PIC apresentaram defeitos que aumentaram com a fadiga mecânica após algum tempo sob ciclagem. As imagens do estereomicroscópio mostram falhas radiais observadas devido à translucidez do material, não houve danos causados pelo aplicador de carga. A distribuição de TMP foi semelhante para os diferentes tipos de substrato, mas o maior módulo de elasticidade mostrou uma concentração de tensão ligeiramente menor. É favorável o uso de PIC em espessura delgada, com resistência à fadiga semelhante à restaurações de ZLS mais espessas. / To investigate the fatigue life, failure modes and stress distribution of partial ultrafine restorations for posterior teeth in different ceramics, sixty standard tabletop preparations in epoxy resin G10 received lithium silicate based zirconia reinforced (ZLS, Vita Suprinity- Vita Zahnfabrik), or hybrid ceramic (PIC, Vita Enamic- Vita Zahnfabrik), restorations in .5 or 1 mm thickness bonded using resin cement. The same cycling protocol was applied for all specimens that consisted of 5.000 cycles at 200 N followed by 450 N cycles until the specimens’ fracture or the suspension of the test after 1.5 x 106 cycles. Axial load was carried out with a 4 Hz frequency in Biocycle V2 equipment (Biopdi, São Carlos, SP), with samples immersed in water. Presence of cracks and/or fractures was checked with every 2,5 x 105 cycles and the survival analysis was performed using the number of cycles in which each specimen failed. All specimens were evaluated using stereomicroscope and scanning electron microscopy (SEM). After data tabulation, Kaplan-Meier and Mantel-Cox (Log Rank test) analysis were performed, followed by multiple pairwise comparison, all with a significance level of 5%, and Weibull analysis. Through tridimensional finite element analysis, stresses distribution and maximum principal stresses in the posterior occlusal veneers were evaluated comparing different types of substrate (G10, enamel/dentin, enamel), thicknesses and ceramic materials. Zirconium-reinforced lithium silicate restorations with 0.5 mm thickness (ZLS.5) showed lower fatigue strength compared to 1.0 mm hybrid ceramic restorations (PIC1), and both were similar to other restorations (PIC.5 and ZLS1) (Log-Rank test, X2 = 11.2; df = 3; p = 0.0107<0.05). ZLS groups presented random defects that culminated with the fracture, whereas PIC groups presented defects that increased with the mechanical fatigue after some time under cycling. Stereomicroscope images show radial cracks observed due to the translucency of the material, there was no damage caused by applicator. TMP distribution was similar for the different substrate types, but the highest modulus of elasticity showed slightly lower stress concentration. PIC is favorable to be used in thin thickness with similar fatigue strength to thicker ZLS restorations.

Abstract Metal ceramic restorations have been used in fixed prosthodontics since the 1950s, but the lack of aesthetics, the inclination to use metal-free materials, possible allergic reactions to metals, and the high cost of high noble alloys have increased the use of all-ceramic materials. The ongoing development of ceramic materials led to the introduction of zirconia to fixed prosthodontics over a decade ago. The mechanical properties of zirconia have proven to be excellent, but the clinical outcome of conventional fixed zirconia restorations over the long term is unclear. This retrospective clinical study evaluated two- to seven-year outcomes, early complications during prosthetic treatment and short-term failures during the first year of use of zirconia single crowns and fixed dental prostheses (FDPs). The usefulness and durability of zirconia single crowns in abutment teeth of partial removable dental prostheses (RDPs) was also evaluated. The material consisted of 173 patients treated with zirconia single crowns or FDPs by undergraduate dental students between 2007 and 2010. Of these patients 94 were women and 79 men (mean age 55 years, range 18–79 years). Altogether 268 zirconia single crowns (mean 3 crowns, range 1–12 crowns per patient) had been fabricated for 88 patients and 120 zirconia FDPs (range 3–12 units, mean 4.5 units) for 102 patients. Seventeen patients had received both crown(s) and FDP(s). The results show that zirconia single crowns and FDPs are a suitable treatment alternative in fixed prosthodontics. Early complications during prosthetic treatment and short-term failures during the first year of use were few. The survival rate of the zirconia single crowns after 3.9 years (2–6 years) was 89% and the success rate was 80%. The survival rate of zirconia FDPs after 4.9 years (3–7 years) was 100% and the success rate was 89%. Zirconia single crowns perform well as abutment teeth of partial RDPs with a metal framework, but fractures in the veneering porcelain remain a problem. / Tiivistelmä Metallokeraamisia rakenteita on käytetty kiinteässä protetiikassa 1950-luvulta lähtien, mutta puutteet estetiikassa, pyrkimys metallittomiin materiaaleihin, mahdolliset allergiset reaktiot ja jalojen metallien korkea hinta ovat lisänneet kokokeraamisten materiaalien käyttöä. Kokokeraamisten materiaalien kehitystyö on tuonut zirkonian kiinteän protetiikan materiaaliksi. Zirkonian mekaaniset ominaisuudet ovat osoittautuneet erinomaisiksi, mutta hammaskantoisten kiinteiden zirkonia-runkoisten proteesien kliiniset pitkäaikaistulokset puuttuvat. Tämän retrospektiivisen kliinisen tutkimuksen tarkoituksena oli selvittää zirkonia-runkoisten yksittäisten kruunujen ja zirkonia-runkoisten siltojen menestymistä 2–7 vuoden aikavälillä sekä kartoittaa niiden valmistuksen aikaiset ongelmat ja varhaiset epäonnistumiset ensimmäisen vuoden aikana. Lisäksi tutkittiin zirkonia-runkoisten yksittäisten kruunujen käyttökelpoisuutta ja kestävyyttä metallirunkoisten rankaproteesien tukihampaina. Materiaali koostui 173 potilaasta, joille hammaslääketieteen opiskelijat olivat tehneet zirkonia-runkoisia yksittäisiä kruunuja tai zirkonia-runkoisia siltoja vuosina 2007–2010. Potilaista 94 oli naisia ja 79 miehiä (keski-ikä 55 vuotta, jakauma 18–79 vuotta). Kaiken kaikkiaan 268 zirkonia-kruunua (keskimäärin 3 kruunua, jakauma 1–12 kruunua potilasta kohti) oli valmistettu 88 potilaalle ja 120 siltaa (keskimäärin 4,5 yksikköä, jakauma 4,5 yksikköä) 102 potilaalle. Seitsemälletoista potilaalle oli tehty sekä kruunuja että siltoja. Tulokset osoittavat, että zirkonia-runkoiset kruunut ja sillat ovat käyttökelpoisia kiinteässä protetiikassa. Valmistuksenaikaiset ongelmat ja varhaiset epäonnistumiset ovat vähäisiä. Yksittäisten kruunujen selviytymisprosentti 3,9 vuoden jälkeen (2–6 vuotta) oli 89 % ja onnistumis-prosentti 80 %. Siltojen selviytymisprosentti 4,9 vuoden jälkeen (3–7 vuotta) oli 100 % ja onnistumisprosentti 89 %. Zirkonia-runkoiset kruunut toimivat hyvin rankojen tukihampaina, mutta niiden ongelmana ovat päällepolttoposliinin lohkeamat.

In the study the influence of different dental technical tools on the surface temperature and phase composition of fixed dental prostheses (FDPs) made of yttria-partially stabilized zirconia polycrystals (3Y-/4Y-/5Y-PSZ) was investigated. FDPs were fabricated by using computer-aided manufacturing (CAM). The FDPs were treated with a contra-angle handpiece equipped with different burs and polishers. The resulting surface temperatures were measured with a thermographic camera, and the resulting phase transformations were investigated by X-ray diffraction and quantified by Rietveld refinement. Processing with burs resulted in no phase transformation, but a preferred orientation shift. Using coarse polisher induced a phase transformation to the rhombohedral phase, while fine polishers produced no relevant phase transformations and no preferred orientation shift. Compared to the monoclinic phase (ca. 9% theoretical volume increase), which is associated with low-temperature degradation (LTD), the rhombohedral phase is much more voluminous (ca. 15% theoretical volume increase) and distorted and, therefore, has a greater degradation potential.

Syfte: Syftet med studien var att undersöka hur olika axiala tryck och skjuvkrafter påverkade marginal och intern passform i en sexledsbro i titan i överkäkens frontregion.Material och metod: En litteratursökning gjordes för att insamla bakgrundsmaterial. Stödtänderna 13 12 11 21 22 23 preparerades på en plastmodell för en sexledsbro och en anatomiskt utformad bro i titan framställdes med hjälp CAD/CAM. En mastermodell av stödtänderna tillverkades i epoxyresin. Genom att använda replikateknik utvärderades brons passform vid olika cementeringstryck; 20, 35, 50, 70 N och 50 N med skjuvkrafter. Varje replika snittades med hjälp av en ”jig” och cementspalten analyserades i ett mikroskop. All data granskades statistiskt.Resultat: Resultatet visade att ett tryck med 20 N generellt gav en ej acceptabel passform och ett tryck med 35 N hade en stor spridning. Vid tryck med 50 N kunde mindre cementspalter ses. De blev inte mindre vid test med 70 N. När skjuvkrafter adderades försämrades resultaten jämfört med försöken med 50 N och 70 N.Konklusion: Ett tryck vid cementering som överstiger 50 N förbättrar ej passformen markant. Närvaro av skjuvkrafter påverkar passformen negativt. Ett lägre tryck på 20 N ger dock en mindre fördelaktig passform jämfört med skjuvkrafter förutsatt att ett tillräckligt högt tryck används. Alla slutsatser var statistiskt signifikanta. / Purpose: The purpose of this study is to investigate how different axial seating loads and shear loads influences the marginal and internal fit of a titanium six unit FDP in the upper jaw frontal region.Materials and Methods: A literature search was made to acquire background material. Preparations of abutment teeth for a six unit FDP 13 12 11 21 22 23 were made on plastic teeth, and an anatomically designed titanium FDP was constructed using CAD/CAM. A master cast of the abutment teeth was fabricated in epoxy resin. Using the impression replica technique the fit of the FDP was evaluated by different seating loads during cementation; 20, 35, 50, 70 N and 50 N under the presence of shear loads. The replicas were sectioned using a jig and the cement gap was analysed using a microscope. All the data were statistically analysed.Results: The results showed that a seating load of 20 N generally gave an unacceptable fit and that the seating load of 35 N had great range. At seating loads of 50 N less cement gaps could be seen, i.e. more favourable fit. These results did not improve when testing with 70 N. With a presence of shear loads the results were poorer than when testing with 50 and 70 N.Conclusions: A seating load exceeding 50 N during cementation does not markedly give a more favourable fit. The presence of shear loads affects the fit negatively. A lower seating load of 20 N gives a less favourable fit compared to shear loads provided that a seating load high enough is used. All of these conclusions were statistically significant.

As próteses totais fixas implantossuportadas tem ganhado cada dia mais seu espaço no tratamento reabilitador de pacientes edêntulos, pois se trata de uma forma de tratamento que atende todos os quesitos funcionais e estéticos. Ainda não existe na literatura um consenso de qual a configuração que melhor distribui as tensões aos implantes e tecidos adjacentes. O objetivo deste estudo foi comparar as tensões geradas na interface osso-implante de próteses totais mandibulares implantossuportadas através do método de correlação de imagens digitais (CID). Foram analisadas duas configurações diferentes quanto a quantidade e posicionamento de implantes (4 ou 5 implantes), diferentes conexões [hexágono externo (HE) e cone morse (CM)] e barras para prótese fixa implantossuportada obtidas por fundição convencional e usinadas pelo sistema CAD/CAM. Foram confeccionados modelos em poliuretano, utilizando implantes de 3,75x11mm, divididos em 8 grupos: G1 (5 implantes/HE/CAD-CAM), G2 (5 Implantes/CM/CAD CAM), G3 (5 Implantes/HE/Convencional), G4 (5 Implantes/CM/Convencional), G5 (4 Implantes/HE/CAD CAM), G6 (4 Implantes/CM/CAD CAM), G7 (4 Implantes/HE/Convencional) e G8 (4 Implantes/CM/Convencional). A análise por CID foi feita quantitativamente e qualitativamente, com aplicação de carga de 250N na fossa central do primeiro molar inferior, onde foram estabelecidas diferentes regiões de interesse para a análise, sendo denominadas de C1 (cervical 1) e A1 (apical 1) para região distal ao último implante, C2 (cervical 2) e A2 (apical) para região mesial ao último implante. Foram encontradas diferenças estatisticamente significantes para o número de implantes em todas as regiões analisadas [C1 (p=0,002), A1 (p=0,01), C2 (p=0,001), A2 (p=0,004)], para as conexões foram encontradas diferenças na região C2 (p<0,05) e para as barras na região A2 (p=0,003). De acordo com os resultados pode-se concluir que as prótese com 4 implantes apresentaram maior quantidade de tensões por tração nas regiões apicais, não houve diferença significativa na concentração de tensões para as conexões HE e CM, exceto para a região C2, onde houve maior concentração de tensão para conexão CM e em comparação ao método de obtenção das barras, as barras convencionais apresentaram maior concentração de tensões de tração nas próteses com 5 implantes. / The implant-supported fixed dental prostheses have been used to rehabilitate edentulous patients as it fulfills not only functional aspects but also esthetic questions. Literature shows that there is no consensus about the best configuration to distribute stress to the implants and surrounding tissues. The objective of this study was to compare the stress generated at the boneimplant interface of implant-supported mandibular dentures by a digital image correlation method (DIC). Two different configurations were analyzed for the implants quantity and position (4 or 5 implants), different connections [external hexagon (EH) and Cone Morse (CM)] and bars for implant-supported fixed prosthesis obtained by conventional casting and machined by CAD/CAM system. Models were prepared from polyurethane and implants (3.75x11mm) were divided in 8 groups: G1 (5 implants/EH/CAD-CAM), G2 (5 Implants/CM/CAD-CAM), G3 (5 Implants/EH/Conventional) , G4 (5 Implants/CM/Conventional), G5 (4 Implants/EH/CAD-CAM), G6 (4 Implants/CM/CAD-CAM) G7 (4 Implants/EH/Conventional) and G8 (4 Implants/CM/Conventional). DIC analysis were quantitative and qualitatively made with a 250N load at first molar central fossa, which were established in different regions of interest for analysis as C1 (cervical 1) and A1 (apical 1) to distal to the last implant, C2 (cervical 2) and A2 (apical) for mesial region to the last implant. Statistically significant differences were found for number of implants in all regions examined [C1 (p=0.002), A1 (p=0.01), C2 (p=0.001) and A2 (p=0.004)], for connections differences were found in the C2 region (p <0.05) and for the bar region at A2 (p=0.003). According to the results it can be concluded that the prosthesis with four implants showed a higher stress at the apical regions, there was no significant difference in the concentration of stress for EH and CM connections, except for the C2 region, where there was a higher concentration of stress for CM connection, and comparing bars obtained methods, conventional bars showed a higher concentration of stresses in prosthesis with 5 implants.

As próteses totais fixas implantossuportadas tem ganhado cada dia mais seu espaço no tratamento reabilitador de pacientes edêntulos, pois se trata de uma forma de tratamento que atende todos os quesitos funcionais e estéticos. Ainda não existe na literatura um consenso de qual a configuração que melhor distribui as tensões aos implantes e tecidos adjacentes. O objetivo deste estudo foi comparar as tensões geradas na interface osso-implante de próteses totais mandibulares implantossuportadas através do método de correlação de imagens digitais (CID). Foram analisadas duas configurações diferentes quanto a quantidade e posicionamento de implantes (4 ou 5 implantes), diferentes conexões [hexágono externo (HE) e cone morse (CM)] e barras para prótese fixa implantossuportada obtidas por fundição convencional e usinadas pelo sistema CAD/CAM. Foram confeccionados modelos em poliuretano, utilizando implantes de 3,75x11mm, divididos em 8 grupos: G1 (5 implantes/HE/CAD-CAM), G2 (5 Implantes/CM/CAD CAM), G3 (5 Implantes/HE/Convencional), G4 (5 Implantes/CM/Convencional), G5 (4 Implantes/HE/CAD CAM), G6 (4 Implantes/CM/CAD CAM), G7 (4 Implantes/HE/Convencional) e G8 (4 Implantes/CM/Convencional). A análise por CID foi feita quantitativamente e qualitativamente, com aplicação de carga de 250N na fossa central do primeiro molar inferior, onde foram estabelecidas diferentes regiões de interesse para a análise, sendo denominadas de C1 (cervical 1) e A1 (apical 1) para região distal ao último implante, C2 (cervical 2) e A2 (apical) para região mesial ao último implante. Foram encontradas diferenças estatisticamente significantes para o número de implantes em todas as regiões analisadas [C1 (p=0,002), A1 (p=0,01), C2 (p=0,001), A2 (p=0,004)], para as conexões foram encontradas diferenças na região C2 (p<0,05) e para as barras na região A2 (p=0,003). De acordo com os resultados pode-se concluir que as prótese com 4 implantes apresentaram maior quantidade de tensões por tração nas regiões apicais, não houve diferença significativa na concentração de tensões para as conexões HE e CM, exceto para a região C2, onde houve maior concentração de tensão para conexão CM e em comparação ao método de obtenção das barras, as barras convencionais apresentaram maior concentração de tensões de tração nas próteses com 5 implantes. / The implant-supported fixed dental prostheses have been used to rehabilitate edentulous patients as it fulfills not only functional aspects but also esthetic questions. Literature shows that there is no consensus about the best configuration to distribute stress to the implants and surrounding tissues. The objective of this study was to compare the stress generated at the boneimplant interface of implant-supported mandibular dentures by a digital image correlation method (DIC). Two different configurations were analyzed for the implants quantity and position (4 or 5 implants), different connections [external hexagon (EH) and Cone Morse (CM)] and bars for implant-supported fixed prosthesis obtained by conventional casting and machined by CAD/CAM system. Models were prepared from polyurethane and implants (3.75x11mm) were divided in 8 groups: G1 (5 implants/EH/CAD-CAM), G2 (5 Implants/CM/CAD-CAM), G3 (5 Implants/EH/Conventional) , G4 (5 Implants/CM/Conventional), G5 (4 Implants/EH/CAD-CAM), G6 (4 Implants/CM/CAD-CAM) G7 (4 Implants/EH/Conventional) and G8 (4 Implants/CM/Conventional). DIC analysis were quantitative and qualitatively made with a 250N load at first molar central fossa, which were established in different regions of interest for analysis as C1 (cervical 1) and A1 (apical 1) to distal to the last implant, C2 (cervical 2) and A2 (apical) for mesial region to the last implant. Statistically significant differences were found for number of implants in all regions examined [C1 (p=0.002), A1 (p=0.01), C2 (p=0.001) and A2 (p=0.004)], for connections differences were found in the C2 region (p <0.05) and for the bar region at A2 (p=0.003). According to the results it can be concluded that the prosthesis with four implants showed a higher stress at the apical regions, there was no significant difference in the concentration of stress for EH and CM connections, except for the C2 region, where there was a higher concentration of stress for CM connection, and comparing bars obtained methods, conventional bars showed a higher concentration of stresses in prosthesis with 5 implants.

Purpose: The purpose of this study is to evaluate how implant-supported fixed dental prosthesis (FDP) restorations with a cantilever at abutment level resist fatigue by dynamic loading and thermocycling depending on the fixture diameters.   Material and method: The study involved two groups with three specimens in each group, based on the diameter of the fixture, 3.5 or 5.0 mm (D3.5 and D5.0). The specimens consisted of two ASTRA TECH platforms, either 3.5 mm or 5.0 mm, 20°Uni Abutments, and a standardized milled CoCr FDP at abutment level with a cantilever. A mounting jig was designed and 3D printed. The specimens underwent a dynamic fatigue test with thermocycling, 5°C and 55°C, and a 250 N load at a frequency of 1.5 Hz for maximum 6×10⁵ cycles, until the specimen either fractured or displayed visible deformation. Fractured specimens were examined under microscope.    Results: In group D3.5, one specimen survived 600,000 cycles without loosening or fracturing, one displayed screw loosening, and one screw fracturing. In group D5,0, two specimens displayed screw fracturing and one screw/abutment loosening.   Conclusions:  · Implant-supported FDP restorations with a cantilever at abutment level tend to resist fatigue better with a larger fixture diameter than with a smaller fixture diameter. · Fixtures with a diameter of 5.0 mm show higher tendency for screw fracturing and loosening compared to fixtures with 3.5 mm.  · More extensive studies regarding implant-supported FDP restorations with cantilever at abutment level and different fixture diameters are required to confirm the results. / Syfte: Syftet med studien är att utvärdera hur implantat-förankrade bro-konstruktioner på distansnivå med frihängande led motstår utmattning genom dynamisk belastning och termocykling beroende på fixturens diameter.   Material och metod: Totalt framställdes två grupper beroende på fixturens diameter, 3,5 eller 5,0 mm, med tre provkroppar per grupp (D3,5 och D5,0). Provkropparna bestod av två fixturer motsvarande position 34 och 35 och ett frihängande led på 36 med plattformarna ASTRA TECH 3,5×9,0 mm eller 5,0×9,0 mm inkluderat distanser 20° Uni Abutment och standardiserade frästa broar i CoCr på distansnivå. Ett dynamiskt utmattningstest genomfördes med hjälp av tuggsimulator med samtidig termocykling 5°C och 55°C. Belastningen på 250 N applicerades på det frihängande ledet under maximalt 6×105 cykler med 1,5 Hz. Provkropparna kontrollerades visuellt och taktilt var 50 000:e cykel för att undersöka om fraktur, deformation eller påverkan på skruvförband uppstått. De frakturerade provkropparna undersöktes i ljusmikroskop för att analysera frakturytor och eventuella deformationer.   Resultat: I grupp D3,5 klarade en provkropp 600 000 cykler utan att lossna eller frakturera, en fick skruvlossning och en fick skruvfraktur. I grupp D5,0 fick två provkroppar skruvfraktur och en fick skruv-/distanslossning.  Slutsats:  · Implantat-förankrade bro-konstruktioner på distansnivå med frihängande led tenderar att motstå utmattning bättre med mindre fixturdiameter än med större fixturdiameter. · Fixturer med diameter 5,0 mm visar större tendens för skruvfrakturer och skruvlossning jämfört med fixturer med 3,5 mm. · Mer omfattande studier beträffande implantat-förankrade bro-konstruktioner på distansnivå med frihängande led och olika fixturdiametrar krävs för att säkerställa resultaten.

Background: The influence of typical manufacturing regimes for producing fixed dental prostheses (FDPs) from yttria partly-stabilized zirconia polycrystals (3Y/4Y/5Y-TZP) on the phase composition is quantified. Methods: Fixed dental prostheses (FDPs) were designed using a CAD process and machined from different Y-TZP blanks from two manufacturers differing in yttria contents. Subsequent to sintering, the FDPs were glaze fired and air-blasted using alumina particles. Phase composition was determined with X-ray diffraction and quantified with Rietveld refinement. Results: The blanks from VITA Zahnfabrik (VITA YZ HT, VITA YZ ST, VITA YZ XT) and Dental Direct (DD Bio ZX2, DD cube ONE, DD cube X2) featured a rhombohedral portion with rather small crystallites and a small monoclinic portion for 3Y/4Y-TZPs, which increased after machining and disappeared after sintering. Glaze firing and air-blasting with alumina particles had no significant influence on the phase composition. Conclusion: The phase history of dental zirconia is revealed, which may have implications on further processing and aging of the FDP (e.g. low temperature degradation) in mouth.

Abstract Oral health among older people is shown to be worse compared to younger people. The aim of this study was to evaluate oral health and associating factors among ageing Finns. A cross-sectional, descriptive epidemiologic survey was performed in Kirkkonummi in southern Finland and in the Lakeus District in northern Finland. Altogether 1,191 subjects aged 60 to 78 years, 625 from Kirkkonummi and 566 from Lakeus, were examined and interviewed. Edentulousness and poor occlusal stability were recorded clinically. Gonial angle, ramus height, condylar height and the amount of residual ridge resorption in the mandible and the presence of fixed prostheses were evaluated from panoramic radiographs. Based on the radiographs the scoring of infection foci was performed with an infection focus index. The signs of infection recorded were deep caries, periapical lesions, furcal lesions, vertical bone pockets and horizontal bone loss. The prevalence of edentulousness was 37%, being significantly higher among women than among men and significantly higher in the northern compared to the southern region. Edentulousness was more prevalent among subjects with primary school education than among those with higher education. The mean of the gonial angle was smaller among dentate subjects than among edentulous ones. Dentate subjects had significantly greater ramus height and condylar height than edentulous subjects. Women had significantly more often than men severe residual ridge resorption in the mandible. Poor satisfaction with dentures associated significantly with poor occlusal stability in both genders. More than three quarters of the subjects had severe risk of infection, more in the southern than in the northern region. In the dentate sample women showed higher prevalence of fixed prostheses than men. In the Kirkkonummi region both men and women had more fixed prostheses than subjects in the Lakeus region. Edentulousness was very frequent among ageing Finns. Mandibular bone morphology changed as a consequence of tooth loss. The prevalence of fixed prostheses was low and the prevalence of signs of infection of dental origin was high. The geographical differences in oral health should be considered by health authorities in order to promote good oral health in rural areas, especially focusing on older people with low socio-economical status and poor health. / Tiivistelmä Vanhusväestön suun terveydentila on useassa tutkimuksessa todettu huonommaksi kuin nuoremmilla. Tämän tutkimuksen tarkoituksena oli selvittää suomalaisen ikääntyvän väestön suun terveydentilaa ja siihen liittyviä tekijöitä. Epidemiologinen poikkileikkaustutkimus tehtiin Kirkkonummella Etelä-Suomessa ja Lakeuden terveyskeskuksen alueella Pohjois-Suomessa. Tutkimukseen ja haastatteluun osallistui yhteensä 1191 iältään 60–78-vuotiasta henkilöä, 625 Kirkkonummelta ja 566 Lakeudelta. Kliinisessä tutkimuksessa selvitettiin hampaattomuus ja proteesien purentatasapaino. Alaleuan leukakulma, nousevan haaran ja nivellisäkkeen korkeus, hammasharjanteen korkeus ja kiinteiden proteesien esiintyminen arvioitiin panoraamaröntgenkuvista. Tulehdusriskiä kuvaava indeksi arvioitiin röntgenkuvien tulehdusmuutoksista, joina rekisteröitiin syvä karies, hampaan juurenpään tulehdus, tulehdus takahampaiden juurten haarautumassa, syventyneet luutaskut ja kiinnityskudoskato usean hampaan alueella. Hampaattomuuden vallitsevuus oli 37 %. Se oli tilastollisesti merkitsevästi korkeampi naisilla kuin miehillä ja pohjoisella alueella merkitsevästi korkeampi kuin eteläisellä. Hampaattomuus oli yleisempää vähiten koulutusta saaneilla kuin korkeamman koulutuksen saaneilla. Hampaallisilla oli pienempi alaleuan leukakulma kuin hampaattomilla, ja heillä oli myös korkeampi nouseva haara ja nivellisäke kuin hampaattomilla. Naisilla oli merkitsevästi useammin vakavaa hammasharjanteen madaltumista kuin miehillä. Molemmilla sukupuolilla tyytymättömyys proteeseihin liittyi merkitsevästi huonoon purentatasapainoon. Yli kolmella neljäsosalla tutkituista oli vakava tulehdusriski, eteläisellä alueella enemmän kuin pohjoisella. Hampaallisessa aineistossa naisilla oli enemmän kiinteitä proteeseja kuin miehillä. Kirkkonummen alueella tutkituilla oli enemmän kiinteitä proteeseja kuin Lakeuden alueella. Hampaattomuus oli hyvin yleistä 60–78-vuotiailla suomalaisilla. Alaleuanluun muoto muuttui hampaiden menetyksen seurauksena. Kiinteiden proteesien määrä oli vähäinen ja ikääntyvillä suomalaisilla oli röntgenkuvissa runsaasti hammasperäisten tulehdusten löydöksiä. Suun terveyden alueelliset erot tulisi ottaa huomioon suu- ja hammasterveyden edistämistyössä, jossa erityisesti tulisi huomioida alhaisen sosioekonomisen aseman ja huonon terveyden omaava vanhempi väestö.