A Computerized Tomographic Data Analysis System to Evaluate the Dental Implant Surface Roughness

AbstractDental implants have been progressively used in the recent years to support and retain dental prosthesis. Implant surface roughness has been suggested as a crucial factor in implant osseointegration and long term survival of the implant and prosthesis, where a key factor for the success or failure of dental implants is the manner in which stresses are transferred to surrounding bone. In this study completely edentulous patients were rehabilitated by implant retained over denture in which two implant systems with different surface roughness were used. Peri implant bone density in Hounsfield Units (HU) was evaluated by analyze Computerized Tomographic (CT) images to judge the behavior of an implant system under functional loading, where DICOM raw data was imported into the analysis proposed system to correlate the bone density regarding to the HU values. Results are compared with clinical readings and previous findings, which it showed that there is a difference in peri implant bone density around regularly patterned and randomly patterned implant surfaces

The effect of in vitro corrosion on the ultimate tensile strength of pins in dentin

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact [email protected] (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1981 (Prosthodontics)Bibliography : leaves 49-56.Rebuilding badly broken-down teeth with pin retained amalgams or composite resin has become an important and popular service provided by the dentist. Teeth previously condemned to extraction are now being salvaged for further use as part of a splint, or as an abutment for fixed bridges or partial dentures. The use of retentive pins to anchor restorative material to a tooth structure is now a well established clinical procedure. Corrosion of intracoronal retentive pins has been observed in previous research (Mobasherat, Pameijer, 1978). The purpose of this investigation was to investigate whether initial corrosion affects the retention of pins in dentin. Various types of pins manufactured by different companies were tested, i.e., gold coated and stainless steel pins. The experimental group was stored in artificial saliva for a period of three (3) months in order to imitate corrosion. The control group was prepared just prior to the actual testing. All pins were exposed to tensile force on an Instron machine. The data indicates that there was no statistically significant difference between the experimental pin systems and their control groups. It is felt that the three (3) month period was not sufficient to determine the possible loss of retention due to corrosion

Dental Mesenchymal Stem Cell-Based Translational Regenerative Dentistry: From Artificial to Biological Replacement

Dentistry is a continuously changing field that has witnessed much advancement in the past century. Prosthodontics is that branch of dentistry that deals with replacing missing teeth using either fixed or removable appliances in an attempt to simulate natural tooth function. Although such “replacement therapies” appear to be easy and economic they fall short of ever coming close to their natural counterparts. Complications that arise often lead to failures and frequent repairs of such devices which seldom allow true physiological function of dental and oral-maxillofacial tissues. Such factors can critically affect the quality of life of an individual. The market for dental implants is continuously growing with huge economic revenues. Unfortunately, such treatments are again associated with frequent problems such as peri-implantitis resulting in an eventual loss or replacement of implants. This is particularly influential for patients having co-morbid diseases such as diabetes or osteoporosis and in association with smoking and other conditions that undoubtedly affect the final treatment outcome. The advent of tissue engineering and regenerative medicine therapies along with the enormous strides taken in their associated interdisciplinary fields such as stem cell therapy, biomaterial development, and others may open arenas to enhancing tissue regeneration via designing and construction of patient-specific biological and/or biomimetic substitutes. This review will overview current strategies in regenerative dentistry while overviewing key roles of dental mesenchymal stem cells particularly those of the dental pulp, until paving the way to precision/translational regenerative medicine therapies for future clinical use

Basic Science

Abstract Stem cells from human exfoliated deciduous teeth (SHED) provide a new attractive source for stem cells; in this study we further characterize SHED. SHED were isolated, differentiated using osteogenic/ odontogenic differentiation media, characterized using light microscope, SEM and immunocytochemistry using CD44. Also, Immunohistochemistry using CD44 was performed on extirpated pulp tissues. We found that a naturally exfoliated human tooth contains a population of stem cells that attain morphological homogeneity after the first passage, on adding the osteogenic/odontogenic medium, sporadic noduleshaped structures were observed after two weeks that were positively stained with alizarin red and von Kossa stains. SHED stained with H& E showed a basophilic, eccentric nucleus with an eosinophilic cytoplasm in which two differently stained areas were clearly distinguishable. Also we found using SEM that SHED spread on the UBM scaffolds surfaces showing multiple filopodia and formed collagen-like structures by the seventh day. After three weeks, seeded scaffolds incubated in osteogenic/odontogenic media showed many mineralized nodules in the ECM. Cultured SHED revealed positive immunoreactivity when treated with CD44. Also, sections of pulp tissue treated with CD44 depict positively stained cells situated mainly in the perivascular areas reinforcing the hypothesis that pericytes may be the origin of SHED

In Vitro Characterization of Stem Cells from Human Exfoliated Deciduous Teeth (SHED)

Abstract Stem cells from human exfoliated deciduous teeth (SHED) provide a new attractive source for stem cells; in this study we further characterize SHED. SHED were isolated, differentiated using osteogenic/ odontogenic differentiation media, characterized using light microscope, SEM and immunocytochemistry using CD44. Also, Immunohistochemistry using CD44 was performed on extirpated pulp tissues. We found that a naturally exfoliated human tooth contains a population of stem cells that attain morphological homogeneity after the first passage, on adding the osteogenic/odontogenic medium, sporadic noduleshaped structures were observed after two weeks that were positively stained with alizarin red and von Kossa stains. SHED stained with H& E showed a basophilic, eccentric nucleus with an eosinophilic cytoplasm in which two differently stained areas were clearly distinguishable. Also we found using SEM that SHED spread on the UBM scaffolds surfaces showing multiple filopodia and formed collagen-like structures by the seventh day. After three weeks, seeded scaffolds incubated in osteogenic/odontogenic media showed many mineralized nodules in the ECM. Cultured SHED revealed positive immunoreactivity when treated with CD44. Also, sections of pulp tissue treated with CD44 depict positively stained cells situated mainly in the perivascular areas reinforcing the hypothesis that pericytes may be the origin of SHED

A study of some physical and mechanical properties of metal filled acrylic resin

This study was performed to evaluate the effect of adding tin or aluminum powder with average particle size of 10/u.m to heat curing acrylic resin in a concentration of 5% by volume. Four physical and mechanical properties were tested for the purpose of this evaluation: thermal conductivity, impact strength, compressive strength, and warpage. The addition of 5% by volume of either metal powder to polymethylmethacrylate (PMMA) improved the four tested properties. However, tin powder was superior to aluminum powder in improving the impact and compressive strength of PMMA, while aluminum powder was superior to tin powder in improving thermal conductivity of PMMA and decreasing its warpage. Both metal powders caused undesirable discoloration to the heat curing acrylic resin. The use of metal-filled resin is therefore recommended in the areas where it is not displayed to get the benefit of improved physical and mechanical properties of PMMA