The Bear River Range, in north-central Utah, contains a variety of geomorphic elements influenced by the geologic setting and events. Controlling factors of the geologic setting include: (1) a syncline (west) and an anticline with a crestal graben (east) within the part of the mountain range studied, and an adjacent graben valley along the west side of the range; and (2) bedrock of Precambrian and Paleozoic age in the core of the range, predominantly of shallow-marine carbonates and covered in the graben by shaly and conglomeratic rocks of early Cenozoic age, with fanglomerates and lake deposits of later Cenozoic age. Geologic events contributing to geomorphic development include: (1) (?) Bull Lake and Pinedale glaciation; ( 2) various levels of Lake Bonneville; and (3) Hypsithermal climatic conditions. The eighteen canyons along the western front of the Bear River Range in Utah, in sequence from north to south, are: High Creek, Oxkiller Hollow, Cherry Creek, City Creek, Nebo Creek, Smithfield, Birch, Dry (North), Hyde Park, Green, Logan, Dry (South), Providence, Millville, Blacksmith Fork, Hyrum, Paradise Dry, and East. An attempt was made to relate gradient changes along longitudinal canyon profiles to lithologies, attitudes, or other structural controls. The only consistent gradient change is a steepening of the gradient downstream from outcrops of Swan Peak Formation. A pronounced asymmetry in cross-valley profiles probably results from micro-climatic differences that cause north-facing slopes to be steeper than southfacing slopes despite close similarities in structure and lithology across canyons. Several canyons which do not cross the syncline axis have no measurable discharge. Water from these drainages apparently moves along the strike or down the east-dipping rocks of the western limb of the Logan Peak syncline to emerge as springs added to the surface flow in cross-axial canyon streams. Leakage is probably concentrated in the Lodgepole and Great Blue Formations. Minor geomorphic elements within the Bear River Range result from glacial, periglacial, and fluvial processes, and landslides. Periglacial action has produced both nivation and patterned diamicton. Glacial features are present in Logan Canyon and its tributaries, Birch, Providence, and the South Fork of Smithfield canyons. In addition to these previously mapped glacial areas, High Creek Canyon was subjected to glacial modification in the upper reach of South Fork tributary, and Leatham Hollow (Blacksmith Fork Canyon ), in the upper reach of its major southern tributary. Nivation modified the heads of Smithfield, Green, Cottonwood, and Dry (South) canyons by carving cirques floored by rock debris. Evidence for glacial action downstream from these cirques is absent. Patterned diamicton sites are widely distributed within the range. There is no consistent relationship to exposed lithologies or physical setting. The apparent relationship of slope aspect, elevation, and solar radiation suggests an origin by a temperature-dependent process, for near-identical temperatures were calculated for all patterned diamicton sites. Based, in part, on a reconstruction of Pleistocene temperatures, the patterned diamicton sites probably are a form of patterned ground resulting from frost action during glacial episodes. Alluvial fans lie at the mouths of many tributary canyons. Based on degree of soil development and relations to features of known age, a sequence of fan development is recognized. Alluvial fans formed prior to Wisconsinan time and repeatedly thereafter during interglacial and glacial periods. Many of the fans formed after the Pleistocene under the favorable conditions that existed during the Hypsithermal interval. Landslides in the study area are commonly old, inactive features. Only a few sites are recent in age, or currently active. Slopes with a west-component aspect are more prone to movement than other aspects. The most frequently disturbed lithology consists of Tertiary formations which are often conglomeratic. A wide range of slope inclinations have landslides, but the dominant slope is 20 to 24 percent. The main elevation range for landslides is between 6, 000 to 6, 999 feet. Quaternary stream alluvium and Lake Bonneville deposits are found along the eastern margin of Cache Valley and in the lower reaches of most canyons. This material has been deposited since the Provo phase of Lake Bonneville. In several places, lake or stream terraces are mapped.

This project examined the effect of splinting adjacent dental implants of different designs [Sintered porous surface (SPS), Threaded dual acid etched (THR-DAE), Threaded sand-blasted large grit acid etched (THR-SLA)] placed in posterior sites and compared two intraoral radiographic techniques to assess peri-implant crestal bone levels. 799 implants located in 345 patients qualified and were examined retrospectively using an inclusion criteria of a minimum one year in function and having a recent periapical (PA) and vertical bitewing radiograph (vBW). SPS had less bone loss than THR-DAA and THR-SLA. PA views showed approximately 0.10 mm (Range 0.07-0.40 mm) less crestal bone loss than vBW (P<0.01). Splinted implants had more crestal bone loss (0.30 mm; range 0.16-0.38 mm) than non-splinted implants. 49 implants failed with an overall failure rate of 4.9% with a significant difference in the failure rate of SPS and THR-DAA (P<0.0005) and in the time to fail (P<0.0036).

This project examined the effect of splinting adjacent dental implants of different designs [Sintered porous surface (SPS), Threaded dual acid etched (THR-DAE), Threaded sand-blasted large grit acid etched (THR-SLA)] placed in posterior sites and compared two intraoral radiographic techniques to assess peri-implant crestal bone levels. 799 implants located in 345 patients qualified and were examined retrospectively using an inclusion criteria of a minimum one year in function and having a recent periapical (PA) and vertical bitewing radiograph (vBW). SPS had less bone loss than THR-DAA and THR-SLA. PA views showed approximately 0.10 mm (Range 0.07-0.40 mm) less crestal bone loss than vBW (P<0.01). Splinted implants had more crestal bone loss (0.30 mm; range 0.16-0.38 mm) than non-splinted implants. 49 implants failed with an overall failure rate of 4.9% with a significant difference in the failure rate of SPS and THR-DAA (P<0.0005) and in the time to fail (P<0.0036).

No description available.

Introduction : Afin de minimiser la morbidité postopératoire et les échecs du traitement dentaire, plusieurs schémas thérapeutiques antibiotiques ont été proposés. Cependant, l’utilisation intensive des antibiotiques dans les soins de santé a été débattue en raison des effets indésirables et la résistance bactérienne. De plus, l’impact des antibiotiques préopératoires sur le niveau osseux péri-implantaire n’est toujours pas clairement établi. Objectifs : L’objectif primaire de cette étude était d’évaluer si l’administration d’un antibiotique préopératoire (azithromycine 500 mg) avant la pose d’implant avait un impact sur les niveaux d’os crestal péri-implantaire après quatre mois chez les patients en bonne santé subissant une pose d’implant simple de type « platform-switching ». Les objectifs secondaires étaient d’évaluer la sévérité de la douleur postopératoire, la morbidité postopératoire associée à la chirurgie implantaire et le taux de survie des implants à quatre mois. Méthodes : Dix-neuf participants ont été recrutés dans un essai clinique randomisé à double insu en groupes parallèles. Les participants du groupe d’intervention ont reçu 500 mg d’azithromycine une heure avant la pose d’implant. Les participants du groupe contrôle ont reçu un placebo identique une heure avant la chirurgie implantaire. Les changements du niveau de l’os crestal péri-implantaire (résultat primaire) ont été mesurés quatre mois plus tard à l’aide de radiographies standardisées. La sévérité de la douleur et la morbidité postopératoire associées à la chirurgie (résultats secondaires) ont été évaluées par des examens cliniques et des questionnaires autoadministrés à une semaine et quatre mois postopératoires. Le taux de survie des implants et la santé péri-implantaire ont été évalués quatre mois après la pose d’implant, avant la mise en charge prothétique. Des analyses descriptives et bivariées ont été utilisées pour analyser les données. Une valeur de P ≤ 0,05 était considérée statistiquement significative. Résultats : Dix-huit participants ont complété l’étude (âge moyen : 52,8 ± 13,9ans). Les changements moyens du niveau osseux péri-implantaire pour le groupe intervention et le groupe contrôle étaient respectivement de -0,79 ± 0,57mm et de -0,35 ± 0,37mm. Il n’y avait pas de différences statistiquement significatives entre les deux groupes en ce qui concerne le remodelage osseux moyen péri-implantaire (-0,44mm (IC 95% : -0,94, +0,55)) et la sévérité de la douleur (P>0,05). Les interférences avec les activités quotidiennes, plus précisément, l’interférence de la chirurgie à ouvrir grand la bouche étaient significativement plus importante chez le groupe antibiotique comparativement au groupe intervention au cinquième jour postopératoire (P<0,05). Le taux de survie des implants était de 100% dans les deux groupes et la santé des tissus péri-implantaires était similaire entre les deux groupes quatre mois après la chirurgie. Conclusion : Les résultats préliminaires de cette étude clinique suggèrent qu’une dose préopératoire d’antibiotique chez les patients en bonne santé ayant une pose d’implant simple de type « platform-switching » n’apporte pas de bénéfice clinique. Des investigations additionnelles de plus grande envergure sont nécessaires afin de confirmer les résultats de cette étude. / Introduction: In order to minimise postoperative morbidity and failures of dental implant therapy, several antibiotic regimens have been proposed. However, the extensive use of antibiotics in health care has been debated due to the adverse effects and bacterial resistance. Furthermore, the impact of preoperative antibiotics on peri-implant bone level remains unclear. Objectives: The primary objective of this study was to assess whether giving a preoperative antibiotic (azithromycin 500mg) before implant placement would influence peri-implant crestal bone levels after four months in healthy patients undergoing straightforward platform-switched implant placement. The secondary objectives were to evaluate postoperative pain severity, surgery-associated morbidities, and four-month implant survival rate. Methods: Nineteen individuals were recruited in a double-masked two-arm randomised clinical trial. Participants in the intervention group received 500mg of azithromycin one hour before implant placement. Participants in the control group took one identical placebo one hour preoperatively. The changes in mesial and distal crestal bone level (primary outcome) were measured at baseline and four-month follow-up using standardised periapical radiographs. Pain severity and surgery-associated morbidities (secondary outcomes) were evaluated by clinical examinations and self-administered questionnaires at one-week and four-month follow-ups. Implant survival rate was assessed at the four-month follow-up. Descriptive and bivariate analyses were used to analyse the data. A P value ≤ 0.05 was considered statistically significant. Results: Eighteen participants completed the study (mean age: 52,8 ±13,9 years). The mean changes in peri-implant bone level for the intervention group and the control group were 0,79 ±0,57 mm and -0,35 ±0,37mm, respectively. There were no statistically significant differences between the two groups in mean change in peri-implant bone level (-0,44mm (95% CI: -0,94, +0,55)) and pain severity (P>0.05). Interferences with daily activities, more specifically the interference of surgery with opening the mouth larger was significantly higher in the antibiotic group compared to the control group (P<0.05) on the fifth postoperative day. The implant survival rate was 100% in both groups and peri-implant tissue health was similar between groups four months after surgery. Conclusion: The preliminary results of this clinical study demonstrates that giving one preoperative dose of antibiotic in healthy patients undergoing straightforward “platform-switching” implant placement does not provide any clinical benefit. Further larger controlled studies are needed to confirm the results of this study.

Purpose: To assess the role of photobiomodulation on bone healing around dental implants. Materials and Methods: 72 patients requiring 76 dental implants were included. All patients received dental implant(s.) Treatment group had also to apply LED to surgical sites. ISQ of implants was measured following implant placement and at 1, 2, 4, and 8 weeks postoperatively. Radiographs were taken after insertion and at 8 weeks postoperatively. Data were analyzed using SPSS and Stata. Results: Treatment group showed an increase in ISQ values over the follow-up period compared to control (p < 0.001). Primary effect of LED on ISQ values was seen over the first 2 weeks (p < 0.05). Treatment group showed less decrease in crestal bone height at 8 weeks (p = 0.05). Conclusions: Data suggest that photobiomodulation will allow for a continuous increase in ISQ value and may reduce crestal bone resorption following implant placement.

Purpose: To assess the role of photobiomodulation on bone healing around dental implants. Materials and Methods: 72 patients requiring 76 dental implants were included. All patients received dental implant(s.) Treatment group had also to apply LED to surgical sites. ISQ of implants was measured following implant placement and at 1, 2, 4, and 8 weeks postoperatively. Radiographs were taken after insertion and at 8 weeks postoperatively. Data were analyzed using SPSS and Stata. Results: Treatment group showed an increase in ISQ values over the follow-up period compared to control (p < 0.001). Primary effect of LED on ISQ values was seen over the first 2 weeks (p < 0.05). Treatment group showed less decrease in crestal bone height at 8 weeks (p = 0.05). Conclusions: Data suggest that photobiomodulation will allow for a continuous increase in ISQ value and may reduce crestal bone resorption following implant placement.

archives@tulane.edu / Minibasins, i.e., small basins that can be up to 8 km in depth and a few tens of km in diameter, often form in regional salt basins and on salt-rich passive margins. As salt walls grow through time, brittle strain localizes in zones directly above the salt walls leading to complex fault arrays surrounding the minibasins. These fault arrays provide insight into the relative movement of minibasins and the local deformation field, which influences the hydrocarbon exploration around them. Using high-resolution bathymetry and 2D reflection seismic data, we have examined fault systems and their interaction with salt walls around the Lyons minibasin in the Gulf of Mexico, offshore USA. This analysis shows that the geometry of salt walls varies and controls the development of faults form in the overlying sedimentary layer. The wide plateau-like salt wall creates a mechanical constraint that restricts the development of faults vertically and laterally. The narrow ridge of the salt wall has less mechanical restriction and allows faults to grow in displacement. Deformation is more localized above the narrow ridge of salt wall. This study suggests that the intricate fault patterns around minibasins result from multi-phase deformation caused by the variation of salt flow within the salt walls. Initially, minibasin subsidence expels salt upward and outward. After the minibasins is welded, the regional slope enhances the lateral flow and allows salt to flow around welded minibasins. During this stage, the lateral flow of salt is constrained by the salt wall orientation. Moreover, this study demonstrates a new approach that provides an additional perspective to understand the evolution of minibasins and their interaction, which is a limitation of 2D modeling studies. / 1 / Thi Quan H. Pham

Este estudo teve como objetivo analisar e comparar o comportamento biomecânico de um implante de comprimento curto com um implante de comprimento padrão, no que diz respeito às tensões ósseas ao redor do implante. Foi considerado como variável o aumento da espessura óssea cortical, em dois tipos: fino e espesso. Os modelos de elementos finitos em três dimensões (3D) foram criados a partir de uma secção de mandíbula de 20 mm, referente ao segundo pré-molar, com um implante endósseo único inserido dentro do osso esponjoso com cortical fina de 0,5 mm e cortical espessa de 2,0 mm. Uma carga oclusal vertical de 100 N e uma carga oblíqua de 40 N foram aplicadas. Os ossos cortical e esponjoso foram considerados isotrópicos e linearmente elásticos e o critério de avaliação foi o de tensões de von Mises. O implante curto utilizado foi de 4,1 mm de diâmetro por 6,0 mm de comprimento, e o implante padrão de 4,1 mm de diâmetro por 10,0 mm de comprimento (ambos da marca Straumann®). A prótese sobre o implante foi composta por um pilar sólido de 5,5 mm de altura e por uma coroa de segundo pré-molar. Conforme as simulações pelo MEF, pôde-se concluir que: 1) O aumento da espessura óssea favoreceu uma melhor distribuição das tensões, registrando valores mais baixos na região cervical cortical. 2) O modelo de implante curto na situação de cortical espessa apresentou melhores resultados biomecânicos comparado com o modelo de implante padrão na situação de cortical fina. / The aim of this monograph was to analyze and compare the biomechanical behavior of a short length implant against a standard length implant, regarding stress distribution on the bone around the implant. Bone cortical thickness of the ridge was considered as thin and thick. The 3D finite element models were created of a 20-mm second premolar section of the mandible with a single endosseous implant embedded in cancellous bone with thin cortical of 0.5 mm and with thick cortical of 2.0 mm. A vertical occlusal load of 100 N and an oblique load of 40 N were applied. The cortical and cancellous bone were considered to be isotropic and linearly elastic Von Mises stress criterion was used for analysis. The short implant used was of 4.1 mm of diameter and 6 mm in length, and the standard implant was of 4.1 mm of diameter and 10 mm in length (both Straumann ®). The prosthesis on the implant consisted of a solid abutment of 5.5 mm in height and a crown of second premolar. Conclusions: 1) Increasing bone thickness favored a better stress distribution, showing lower values in the cervical cortical bone. 2) Short implants with thin cortical situations showed better biomechanical results compared to standard implants with thick cortical situations.

Este estudo teve como objetivo analisar e comparar o comportamento biomecânico de um implante de comprimento curto com um implante de comprimento padrão, no que diz respeito às tensões ósseas ao redor do implante. Foi considerado como variável o aumento da espessura óssea cortical, em dois tipos: fino e espesso. Os modelos de elementos finitos em três dimensões (3D) foram criados a partir de uma secção de mandíbula de 20 mm, referente ao segundo pré-molar, com um implante endósseo único inserido dentro do osso esponjoso com cortical fina de 0,5 mm e cortical espessa de 2,0 mm. Uma carga oclusal vertical de 100 N e uma carga oblíqua de 40 N foram aplicadas. Os ossos cortical e esponjoso foram considerados isotrópicos e linearmente elásticos e o critério de avaliação foi o de tensões de von Mises. O implante curto utilizado foi de 4,1 mm de diâmetro por 6,0 mm de comprimento, e o implante padrão de 4,1 mm de diâmetro por 10,0 mm de comprimento (ambos da marca Straumann®). A prótese sobre o implante foi composta por um pilar sólido de 5,5 mm de altura e por uma coroa de segundo pré-molar. Conforme as simulações pelo MEF, pôde-se concluir que: 1) O aumento da espessura óssea favoreceu uma melhor distribuição das tensões, registrando valores mais baixos na região cervical cortical. 2) O modelo de implante curto na situação de cortical espessa apresentou melhores resultados biomecânicos comparado com o modelo de implante padrão na situação de cortical fina. / The aim of this monograph was to analyze and compare the biomechanical behavior of a short length implant against a standard length implant, regarding stress distribution on the bone around the implant. Bone cortical thickness of the ridge was considered as thin and thick. The 3D finite element models were created of a 20-mm second premolar section of the mandible with a single endosseous implant embedded in cancellous bone with thin cortical of 0.5 mm and with thick cortical of 2.0 mm. A vertical occlusal load of 100 N and an oblique load of 40 N were applied. The cortical and cancellous bone were considered to be isotropic and linearly elastic Von Mises stress criterion was used for analysis. The short implant used was of 4.1 mm of diameter and 6 mm in length, and the standard implant was of 4.1 mm of diameter and 10 mm in length (both Straumann ®). The prosthesis on the implant consisted of a solid abutment of 5.5 mm in height and a crown of second premolar. Conclusions: 1) Increasing bone thickness favored a better stress distribution, showing lower values in the cervical cortical bone. 2) Short implants with thin cortical situations showed better biomechanical results compared to standard implants with thick cortical situations.