18 research outputs found

    Effect of miniscrew implant design characteristics and bone properties on insertion torque for primary stability: An Invitro study

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    AIM OF THE STUDY: The aim of our study was to evaluate the geometrical design characteristics (lead angle of thread, pitch, depth, taper, number of threads, surface area, thread length, diameter, thread type) of 2 commercially available self drilling tapered miniscrew implants using scanning electron microscopy (SEM) and to evaluate the effects of each geometrical design parameters of MSI's on primary stability using insertion torque in different cortical bone thickness. MATERIAL AND METHOD: A total of 60 titanium miniscrew implants (MSI's) were used in this study,consisting of 30 MSI's each from two different manufacturers (Dentos Korea, SK Surgicals India). MSI's were grouped into small, medium and large according to their diameters as 1.3mm, 1.5mm and 1.8mm respectively. All MSI's had a standard length of 8mm. All the MSI's used in this study were tapered and self-drilling type. Precise measurement of all MSI geometric design parameters were evaluated using scanning electron microscopy (SEM) and Image J software. Mechanical evaluation of insertion torque was done to evaluate primary stability. RESULTS: Geometric design characteristics like decreasing the MSI pitch distance, increasing the number of threads, maintaining a uniform MSI taper and increasing the surface area of MSI's plays an important role to achieve optimal insertion torque and thereby enhancing primary stability.An increase in lead angle increases the cutting efficiency of MSI. Therefore MSI's with higher lead angles are recommended for easy insertion of MSI in thick cortical areas.Increase in MSI depth reduces the core diameter of the MSI and are more prone to fracture. An increase in the diameter of the MSI and cortical bone thickness which increases the insertion torque will enhances the primary stability CONCLUSIONS: A great variability in the geometric design characteristics of MSI was observed. On the basis of the present outcomes it is assumed that MSI design parameters could be strategically matched, in order to improve its performance, according to insertion site characteristics and clinical demands concerning the directions of the forces applied. So, the clinicians must know these geometric design characteristics of MSI's in order to increase the success rates of their procedures

    PRELIMINARY FINDINGS OF A POTENZIATED PIEZOSURGERGICAL DEVICE AT THE RABBIT SKULL

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    The number of available ultrasonic osteotomes has remarkably increased. In vitro and in vivo studies have revealed differences between conventional osteotomes, such as rotating or sawing devices, and ultrasound-supported osteotomes (Piezosurgery庐) regarding the micromorphology and roughness values of osteotomized bone surfaces. Objective: the present study compares the micro-morphologies and roughness values of osteotomized bone surfaces after the application of rotating and sawing devices, Piezosurgery Medical庐 and Piezosurgery Medical New Generation Powerful Handpiece. Methods: Fresh, standard-sized bony samples were taken from a rabbit skull using the following osteotomes: rotating and sawing devices, Piezosurgery Medical庐 and a Piezosurgery Medical New Generation Powerful Handpiece. The required duration of time for each osteotomy was recorded. Micromorphologies and roughness values to characterize the bone surfaces following the different osteotomy methods were described. The prepared surfaces were examined via light microscopy, environmental surface electron microscopy (ESEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy. The selective cutting of mineralized tissues while preserving adjacent soft tissue (dura mater and nervous tissue) was studied. Bone necrosis of the osteotomy sites and the vitality of the osteocytes near the sectional plane were investigated, as well as the proportion of apoptosis or cell degeneration. Results and Conclusions: The potential positive effects on bone healing and reossification associated with different devices were evaluated and the comparative analysis among the different devices used was performed, in order to determine the best osteotomes to be employed during cranio-facial surgery

    2005 - 2006 University Catalog

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    This is a one-year CATALOG, effective beginning Summer Quarter 2005.https://scholarsrepository.llu.edu/univcatalog/1010/thumbnail.jp

    An谩lisis de la capacidad de osteointegraci贸n de diferentes revestimientos de superficie de implantes dentales de titanio

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    La presente tesis doctoral, presentada por compendio de publicaciones, tuvo como objetivo evaluar la din谩mica de cicatrizaci贸n 贸sea alrededor de implantes dentales con diferentes recubrimientos y tratamientos superficiales, y compararla con implantes con superficie grabada convencional sin tratamiento adicional. Est谩 basada en cuatro art铆culos publicados en revistas con factor de impacto, del primer cuartil. Todos los art铆culos giran entorno a los revestimientos y funcionalizaci贸n de las superficies de los implantes dentales de titanio ya que, en la actualidad, los revestimientos de superficie se han transformado en una de las l铆neas de investigaci贸n con mayor atractivo para los investigadores del sector dental. El primer estudio, evalu贸 la osteointegraci贸n y la formaci贸n 贸sea a diferentes niveles, de los implantes de titanio recubiertos con quitosano, en la mand铆bula de un modelo de canino, observ谩ndose que, en los implantes recubiertos con quitosano, el an谩lisis de la tendencia en el grupo experimental mostr贸 una significaci贸n estad铆stica considerable, en comparaci贸n con el grupo control. El segundo, analiz贸 el efecto de la BMP-7 sobre los par谩metros biol贸gicos relacionados con la osteointegraci贸n de implantes dentales de titanio, con superficies tratadas mediante 谩cido carboxietilfosf贸nico. Los resultados preliminares de este estudio precl铆nico mostraron que, al cabo de cuatro semanas, los implantes experimentales con superficie tratada con 谩cido carboxietilfosf贸nico, funcionalizado con BMP-7, obtuvieron diferencias estad铆sticamente significativas para los par谩metros histomorfom茅tricos BIC (Bone Implant Contact) y BIC corregido, en comparaci贸n con el grupo de control; sin embargo, no se encontraron diferencias entre los grupos para la formaci贸n de hueso nuevo y la densidad 贸sea. El tercer art铆culo se centr贸 en una visi贸n general de los conceptos y teor铆as actuales de la osteointegraci贸n y las superficies y recubrimientos actuales de los implantes dentales de titanio, con especial atenci贸n a la investigaci贸n in vivo, de los implantes recubiertos con quitosano y una perspectiva actual sobre el futuro de los recubrimientos de los implantes dentales de titanio; adem谩s se describi贸 un novedoso m茅todo de revestimiento, en v铆as de patentado. El cuarto art铆culo es una revisi贸n sistem谩tica y metaan谩lisis, sobre la efectividad de las superficies bioactivas en la osteointegraci贸n de los implantes dentales de titanio, con la conclusi贸n que la modificaci贸n de las superficies de los implantes, mediante mol茅culas bioactivas org谩nicas, aunque parece favorecer la osteointegraci贸n en las primeras fases de cicatrizaci贸n, no aporta pruebas definitivas de ello

    Virginia Commonwealth University Courses

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    Listing of courses for the 2021-2022 year

    2006 - 2007 University Catalog

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    Volume 96, Number 1, June 30, 2006 Published once a year June 30, 2006https://scholarsrepository.llu.edu/univcatalog/1009/thumbnail.jp

    Virginia Commonwealth University Courses

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    Listing of courses for the 2022-2023 year

    Virginia Commonwealth University Courses

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    Listing of courses for the 2019-2020 year

    2016 - 2017 University Catalog

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    This is a one-year Catalog, effective beginning Summer Quarter 2016. Volume 105, Number 1, July 2016https://scholarsrepository.llu.edu/univcatalog/1000/thumbnail.jp

    Postgraduate Unit of Study Reference Handbook 2009

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