PURPOSE: The purpose of this study was to analyze anatomical spatial limitations of the existing bone for maxillary anterior implant placement in normal subjects. MATERIALS AND METHODS: Fifty Two (52) Cone Beam Computed Tomography (CBCT) scans were selected. A 3i Osteotite (6 x 15mm) implant was superimposed on tooth positions from the right first premolar to left first premolar on reformatted cross sectional mages of maxillary anterior teeth. For the first trial, the implant was positioned following the alveolar bone axis. Utilizing Invivo 5 Software (Anatomage), the proximal overlaps between superimposed implants were evaluated at successive vertical steps of 2.5 mm. The prospective crown angulation or PCA (defined as the angulation between the crown axis and alveolar bone axis) was measured. The inter-canine distance across the arch, the palatal plane length and the palatal bony angulation (defined as the angulation between the palatal surface and the alveolar bone axis) were also measured. For the second trial, implant positioning followed a prosthetic driven position; the crown axis. The crown axis was defined as a line drawn from the midpoint of a line between the mid buccal/lingual CEJ to the incisal edge. The crest height and the apical height at which the implant's 1mm sleeve penetrated the buccal wall were calculated. RESULTS: The implant position at the central incisor and lateral incisor presented the highest percentage of overlap in both the biologically and prosthetically driven positions. The prospective crown angulation was higher at the location of the lateral incisor compared to the central incisor and canine position. The association between the remaining anatomical parameters and the prevalence of overlap was analyzed with bi-serial correlation. There was no significant relationship among any of these parameters. When the implant was simulated in a prosthetically driven position, the lateral incisor implant position frequently showed perforation at 5mm apical to the buccal crest margin demonstrating this position as highly sensitive. SUMMARY: The data demonstrated that the constriction of the alveolar bony volume in the anterior maxilla could affect implant placement. Understanding this bone morphology suggests a major limitation in the central/lateral positions which might require bone grafting. A new unique reference plane was utilized for this study. / 2018-09-28T00:00:00Z

Objective: To assess neck angulation and endograft oversizing as factors contributing to folding. Endograft folding will then be assessed on its role in endograft fixation strength. Methods: Bench top flow loop experiments were performed with barbless Gore Excluder endovascular grafts (EVG) that were deployed into silicone aorta-AAA models with neck angles of 0, 30, and 60. A total of five oversizings were tested: -7%, 2%, 12%, 24%, and 38% with N= 3 for each oversizing at each neck angle for a total of 45 experiments. Photographs of the stent apex to apex distances were taken for the entire circumference of the device for a total of 8 photos per experiment. Measurements of the apex to apex distance were taken for the top three stent layers and variance for each stent layer was calculated. Variances for all three stent layers were summed to represent the folding metric. The silicone model was then removed from the flow loop and placed on the uniaxial extension tester to for pull out testing to assess impact on attachment strength. Results: Neck angle and oversizing increases folding risk at oversizing ≥12% for 0° and 30° neck angles, and ≥ 2% oversizing for a 60° neck angle. Folding metric comparison between 0° vs. 30° and 0° vs. 60° across all oversizings had statistical significance (Mann-Whitney U, p

Introduction: The purpose of this study was to evaluate the changes in marginal ridge alignment occurring through normal growth and development from early childhood to late adulthood and to examine if any statistical variation exists between males and females. Methods: Dental casts of 38 subjects (15 females and 23 males) from the Iowa Growth Study were selected. The marginal ridge discrepancy was measured as the absolute value difference between adjacent marginal ridges of 20 interproximal contacts with both the ABO tool (data not shown) and a vertically mounted digital caliper. Upper and lower casts were tripoded to a level plane defined by the most posterior tooth and central point of the most erupted central incisor. A 15 subject calibration was used to measure inter-examiner reliability using the Cronbach’s Alpha and Kappa tests. The independent samples t test was used to examine the correlation of marginal ridge discrepancies between males and females. Results: Cronbach alpha (p ≤ .001) and Kappa test (p ≤ .01) show excellent inter-rater reliability. The independent sample t test showed no statistical significance, with minimal exception, in marginal ridge discrepancies between males and females matched for age (p > .05). Group 1 showed significantly higher number of marginal ridge discrepancies within ABO range of 0 – 0.5 mm of males and females compared to Group 2. Conclusion: Based on this study, no statistically significant differences were found in marginal ridge discrepancies between males and females. Also, the magnitude of marginal ridge discrepancies of erupting permanent teeth shows a decrease as an individual proceeds through growth and development and they remain relatively “level” during primary dentition.

No description available.

Orientador: Osmar Aparecido Cuoghi / Banca: Marcos Rogério de Mendonça / Banca: Claudenir Rossato / Resumo: A presente pesquisa teve como objetivo comparar os valores médios normais das angulações mesiodistais dentárias, propostos por Ursi em 1989, com as angulações mesiodistais de caninos, pré-molares e molares inferiores em indivíduos com e sem a presença dos terceiros molares inferiores. Além disso, foram comparados os valores das angulações mesiodistais de caninos, pré-molares e molares inferiores nestas duas situações. Para a realização deste trabalho, foram utilizadas 40 radiografias ortopantomográficas de indivíduos de ambos os gêneros que não receberam tratamento ortodôntico, divididos em dois grupos: Grupo I, constituído por 20 radiografias que não apresentavam os terceiros molares inferiores e Grupo II, formado por 20 radiografias com os terceiros molares inferiores presentes. Para realização das mensurações, uma folha de papel de acetato "Ultraphan" foi adaptada sobre cada radiografia, permitindo o traçado do contorno externo da imagem da mandíbula, forames mentonianos, linha intermentoniana, contorno de caninos, pré-molares e molares inferiores e longos eixos dos dentes. Os desenhos anatômicos foram digitalizados e os ângulos formados pela intersecção dos longos eixos dos dentes com a linha intermentoniana foram medidos pelo programa AutoCAD 2000. A análise dos resultados e a análise estatística permitiram concluir que ambos os Grupos exibiram pré-molares e molares inferiores mais angulados em sentido mesial quando comparados à oclusão normal. Por outro lado, a angulação mesiodistal de caninos inferiores mostrou-se semelhante àquela apresentada em casos de oclusão normal. Os dois Grupos, quando comparados entre si, exibiram valores angulares dos caninos, pré-molares e molares inferiores semelhantes, de modo que a presença dos terceiros molares não exerceu influência sobre estas angulações mesiodistais dentárias. / Abstract: The present research had as objective compare the normal medium values of the mesiodistal axial angulation, proposed by Ursi in 1989, with the mesiodistal axial angulation of canine teeth, premolar and inferior molars in individuals with and without the presence of the third inferior molars. Besides, the values of the mesiodistal axial angulation of canine, premolar and inferior molars were compared in these two situations. For the accomplishment of this work, they were used 40 panoramic x-rays from individuals of both sexes that didn't receive orthodontic treatment, divided in two groups: Group I, constituted by 20 x-rays that didn't present the third inferior molars and Group II, formed by 20 x-rays with the presence of the third inferior molars. For accomplishment of the measurements, a leaf of paper of acetate "Ultraphan" was adapted on each x-ray, allowing the plan of the mandibles' external outline, mental foramen, reference line passing through the centers of the mental foramens, outline of canine, premolar and inferior molars and long axes of these teeth. The anatomical drawings' digitization allowed the measurement of the angles formed by the encounter of the long axes of the teeth with the reference line through AutoCAD 2000 program. The results analysis and the statistical analysis allowed concluding that both Groups exhibited inferior premolar and molars more angulated in mesial direction when compared to the normal occlusion. On the other hand, the mesiodistal axial angulation of inferior canine teeth was shown similar that presented in cases of normal occlusion. The two Groups, when compared amongst themselves, exhibited similar angular values of the canine teeth, premolar and inferior molars, so that the presence of the third molars didn't exercise influence on these dental angulations. / Mestre

Made available in DSpace on 2014-06-11T19:27:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-11-17Bitstream added on 2014-06-13T18:32:10Z : No. of bitstreams: 1 sella_rc_me_araca.pdf: 1441654 bytes, checksum: cdc70411fdffc721aad7006bd91c1278 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A presente pesquisa teve como objetivo comparar os valores médios normais das angulações mesiodistais dentárias, propostos por Ursi em 1989, com as angulações mesiodistais de caninos, pré-molares e molares inferiores em indivíduos com e sem a presença dos terceiros molares inferiores. Além disso, foram comparados os valores das angulações mesiodistais de caninos, pré-molares e molares inferiores nestas duas situações. Para a realização deste trabalho, foram utilizadas 40 radiografias ortopantomográficas de indivíduos de ambos os gêneros que não receberam tratamento ortodôntico, divididos em dois grupos: Grupo I, constituído por 20 radiografias que não apresentavam os terceiros molares inferiores e Grupo II, formado por 20 radiografias com os terceiros molares inferiores presentes. Para realização das mensurações, uma folha de papel de acetato Ultraphan foi adaptada sobre cada radiografia, permitindo o traçado do contorno externo da imagem da mandíbula, forames mentonianos, linha intermentoniana, contorno de caninos, pré-molares e molares inferiores e longos eixos dos dentes. Os desenhos anatômicos foram digitalizados e os ângulos formados pela intersecção dos longos eixos dos dentes com a linha intermentoniana foram medidos pelo programa AutoCAD 2000. A análise dos resultados e a análise estatística permitiram concluir que ambos os Grupos exibiram pré-molares e molares inferiores mais angulados em sentido mesial quando comparados à oclusão normal. Por outro lado, a angulação mesiodistal de caninos inferiores mostrou-se semelhante àquela apresentada em casos de oclusão normal. Os dois Grupos, quando comparados entre si, exibiram valores angulares dos caninos, pré-molares e molares inferiores semelhantes, de modo que a presença dos terceiros molares não exerceu influência sobre estas angulações mesiodistais dentárias. / The present research had as objective compare the normal medium values of the mesiodistal axial angulation, proposed by Ursi in 1989, with the mesiodistal axial angulation of canine teeth, premolar and inferior molars in individuals with and without the presence of the third inferior molars. Besides, the values of the mesiodistal axial angulation of canine, premolar and inferior molars were compared in these two situations. For the accomplishment of this work, they were used 40 panoramic x-rays from individuals of both sexes that didn't receive orthodontic treatment, divided in two groups: Group I, constituted by 20 x-rays that didn't present the third inferior molars and Group II, formed by 20 x-rays with the presence of the third inferior molars. For accomplishment of the measurements, a leaf of paper of acetate Ultraphan was adapted on each x-ray, allowing the plan of the mandibles' external outline, mental foramen, reference line passing through the centers of the mental foramens, outline of canine, premolar and inferior molars and long axes of these teeth. The anatomical drawings' digitization allowed the measurement of the angles formed by the encounter of the long axes of the teeth with the reference line through AutoCAD 2000 program. The results analysis and the statistical analysis allowed concluding that both Groups exhibited inferior premolar and molars more angulated in mesial direction when compared to the normal occlusion. On the other hand, the mesiodistal axial angulation of inferior canine teeth was shown similar that presented in cases of normal occlusion. The two Groups, when compared amongst themselves, exhibited similar angular values of the canine teeth, premolar and inferior molars, so that the presence of the third molars didn't exercise influence on these dental angulations.

By enabling coordinated task execution and movement, robotic swarms can achieve efficient exploration or disaster site management. When utilizing Ultra-wideband (UWB) radio technology for ranging, the proposed relative localization sensor can be made lightweight and relatively indifferent to the ambient environment. Infrastructure dependency is eliminated by making the whole sensor fit on a swarm agent, while allowing for a certain amount of positional error. In this thesis, a novel algorithm is implemented in to constrained hardware and compared to a more traditional trilateration approach. Both algorithms utilize Particle Swarm Optimization (PSO) to be more robust towards noise and achieves similar accuracy, but the proposed algorithm can run up to ten times faster. The antenna array which forms the localization sensor weighs only 56g, and achieves around 0.5m RMSE with a 10Hz update rate. Experiments show that the accuracy can be further improved if the rotational bias observed in the UWB devices are compensated for.

No description available.

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.

This study aimed to investigate the course of the nasolacrimal drainage system in three different brachycephalic dog breeds in comparison to normocephalic dogs and to draw conclusions on potentially adverse consequences for the drainage function. A computed tomographic-dacryocystography (CT-DCG) was performed in 51 brachycephalic dogs, consisting of 23 Pugs, 18 French and 10 English bulldogs. Six normocephalic dogs of different breeds and body size served as a comparison. Two- and three dimensional images were obtained and evaluated. Several parameters (length, angulation, gradient) were used to describe the nasolacrimal drainage system and to quantify distinctions between different breeds. Furthermore several additional characteristics were analysed, including the relative position of lacrimal foramen and nasolacrimal ostium, crossing of the nasolacrimal duct below the root of the upper canine tooth, the patency of the lacrimal drainage system and the presence of an accessory opening. While the length of the nasolacrimal duct is substantially reduced in brachycephalic dogs, their lacrimal canaliculi have much larger dimensions than those of normocephalic dogs. Additionally varying parts of the nasolacrimal drainage system follow an inverse direction in short-headed dogs, giving the entire nasolacrimal apparatus a characteristic U- or V-shaped appearance. The nasolacrimal duct exhibits a much steeper alignment in brachycephalic dogs compared to normocephalic ones. This strong slope however does not interfere with drainage function because of a consistently present accessory opening, being the main or only outflow pathway in all brachycephalic dogs and hence facilitating proper tear drainage regardless of the steepness.