The nature of dental implants as a treatment plan for patients is often viewed as something relatively new, but the idea of dental implants has long been a part of history. Dating back as far as the Mayan civilization, dental implants have increasingly become prevalent in modern society. As time progressed, various modern forms of dental implants materialized, with the first of these being the eposteal implant. Post 1943, the eposteal dental implants were then replaced by the more novel transosteal implants, and then followed by the current implant model, the endosteal implant. Presently, in the US alone, there are upwards of 700,000 implants being inserted annually so there is no question of the impact dental implants have, and will continue to have, on dentistry and quality of life for patients. Implants are often evaluated in terms of success versus survival, where "success" is denoted if a particular implant meets the success criteria it is being evaluated with, while "survival" simply means the implant exists in the mouth. The impasse that arises here is that the two terms of success and survival are so closely intertwined that implant success can be misrepresented, and wrongfully thought of as ubiquitous among all patients. This literature review takes a comprehensive look at dental implants, and proceeds to evaluate associated case studies as well as posit how implants affect modern day dentistry.

This program of research investigated the role of cognitive factors in adjustment to cochlear implantation. A cochlear implant is a medical device for severe to profoundly deaf individuals that simulates sound in the cochlea by electrically stimulating the hearing nerve. The audiological benefits of implantation have shown to be highly variable and difficult to predict. This has led to the utilisation of psychological factors to predict adjustment. The aim of this thesis was to develop an understanding of the psychological factors influencing adjustment to implantation within a cognitive framework. Three studies were conducted that investigated the central hypothesis that individuals with a maladaptive cognitive style are more likely to experience poorer psychological adjustment following implantation. Study 1 was a cross-sectional survey that aimed to identify the main predictors of post-implant adjustment in a large representative sample of adult cochlear implant recipients. Participants completed measures of hearing-related cognitions, anxious and depressive symptomatology, emotional reaction to the implant, and hearing-related demographic characteristics. Psychological adjustment was assessed as stress and coping in relation to hearing impairment. The tendency to engage more frequently in negative hearing-related cognitions was found to be the strongest predictor of adjustment. This finding was consistent with the hypothesis that a maladaptive cognitive style plays a key role in determining psychological outcomes following implantation. Study 2 extended Study 1 by experimentally investigating the impact of a specific maladaptive cognitive process, rumination, on cochlear implant recipients' response to an auditory task. Based on the Study 1 finding that negative cognitions predicted poorer adjustment, participants engaged in either a positive or negative rumination task. During rumination, participants focussed on a series of either positive or negative self-statements. Following rumination, participants completed an auditory (story listening) task. Participants then rated their mood, extent of negative cognitions, and the perceived difficulty of the auditory task. Inconsistent with predictions, participants who engaged in negative rumination did not respond more negatively on any of the ratings than participants who engaged in positive rumination. A correlational analysis, however, showed that greater perceived task difficulty was associated with lower frequency of engagement in positive cognitions about hearing. Study 3 employed a thought suppression paradigm to investigate in cochlear implant recipients the effects of suppressing thoughts about hearing difficulty during an auditory task. It was predicted that participants instructed to suppress would experience an increased frequency of target thoughts and greater negative mood, both during and after suppression. During the first (baseline) experimental period, both suppression and non-suppression participants monitored their thoughts by pressing a button when they experienced a thought about hearing difficulty. In the second (suppression) period, suppression participants suppressed their thoughts about hearing difficulty. In the third (post-suppression) period, suppression participants were instructed to no longer suppress their thoughts. Participants who suppressed had an increased frequency of target thoughts subsequent to, but not during, suppression. There were no differences between suppression and non-suppression participants for mood, either during or after suppression. The finding of a delayed increase in target thoughts indicated that attempting to suppress thoughts about hearing difficulty may be a maladaptive cognitive strategy for managing unwanted negative cognitions about hearing in cochlear implant recipients. In concluding, the thesis proposes a cognitive model of adjustment to cochlear implantation that synthesises the findings of the studies conducted and takes into account the cognitive theories that informed the program of research. The major components of this model include the tendency to engage in negative hearing-related cognitions, the maladaptive cognitive processes employed to manage negative hearing-related cognitions, and cognitive load factors. While far from conclusive, the model presents an initial framework within which the current findings can be understood and further hypotheses generated. Methodologically, the model also provides an empirically informed framework for future investigations into the cognitive factors associated with adjustment in cochlear implant users.

Hydroxyapatite ( HA ) coatings are widely used on metal implant devices to improve biocompatibility, enhance bonding strength and to shorten bonding aging between the implant and natural bones. Current coating methods share a common drawback : coatings produced by these processes are not crystalline and further heat treatment must be performed at high temperature ( 700 ° C ). Unfortunately, this treatment often reduces the bonding strength between the coating layer and the metal substrates and may cause chemical degradation of the HA. Recently, a biomimetic coating method has been developed. The strategy adopted in this method is to induce formation of the HA layer by coating implant surfaces with biologically inspired functional groups. This attempts to simulate the natural mineralization process occurring in the human body and it is hoped that the low crystallinity problem may be overcome. Unfortunately, industrial - scale production is not attractive due to the slow growth rate of the crystalline layer. Several weeks are required to produce a detectable thickness of HA and the deposited layer ' s in - vivo performance has not been quantified. As a consequence, further studies elucidating the key factors influencing formation of the HA layers and its in - vivo performance are desirable. In this study, self - assembled monolayers ( SAM layers ) with different functional groups were produced on titanium substrates and characterized. The titanium substrates were immersed in simulated body fluid ( SBF ) to synthesize HA coatings. After measuring the chemical compositions, crystallinity, morphology and growth rates of those coatings, the optimal SAM for HA formation was determined. In addition, the influences of key variables such as temperature, pH, ionic concentrations and functional groups on HA formation were investigated. The goal of this work was to accelerate the growth of the HA coatings for industrial scale production. Finally, human bone cells behaviors on HA coated titanium were observed to confirm an improvement in the biocompatibility and bioconductivity. It was found that SAMs significantly enhanced the formation of HA coatings on titanium surface. The optimum functional group for the SAM was - COOH. This functional group produced the fastest rate of formation and a HA coating with morphological attributes and crystallinity most like natural bone. Significant factors affecting HA formation on - COOH SAM were temperature, calcium concentration and Ca / P ratio in SBF. Significantly, it was discovered that higher temperatures and calcium concentration in SBF substantially increased rate of growth of the HA coating whilst appearing not to adversely affect crystallinity. This could reduce time for producing SAM induced HA coatings on titanium implants from a month to a week. Finally, the HA coating formed at 37 ° C on - COOH SAM substantially enhanced the growth of human bone cells on the titanium surface. / Thesis (M.Eng.Sc.)--School of Chemical Engineering, 2005.

<p>A study was carried in conjunction with the Orthodontic department at Halmstad General Hospital in Sweden to investigate the possibility of reducing cost and manufacture time of dental implant drill guides. </p><p>The current system involves sending a digital image in STL format to the Materialise factory in Belgium where information of the position of dental implants is translated onto a moulded mouthpiece. Drill guides are placed in the mouth piece which is then returned to the surgeon. The mouthpiece complete with drill guides is then placed in the patients mouth and used as a guide for the implant drill holes. The cost of 10000 sek and a turnaround time of 2 weeks gave rise to the need for a faster and cheaper solution. </p><p>A new mouthpiece was designed comprising of a solid cube which could be clearly seen on the x-ray. Linearisation of the cube faces is used to find a reference point from which to drive a 5 axis drilling platform. The mouthpiece is placed in the drill platform which is driven by stepper motors which in turn are controlled by a microcontroller. Co-ordinates are entered via a PC interface. The PC software then translates these co-ordinates into motor steps which are sent to the microcontroller. The drill platform then positions the mouthpiece in order to drill guide holes for the dental implants. </p><p>The study showed that the machine design gave an acceptable degree of accuracy and repeatability. Further enhancements could be made by automating the detection of the cube using image analysis techniques. The study was also limited by the lack of graphical and geometrical data concerning the position of the implant. For the purpose of this study the co-ordinates for the implants guides is entered by hand.</p><p>It was concluded that further software and hardware enhancement would be needed before the application could be developed commercially.</p>

Thesis (Ph. D.)--University of Texas at Dallas, 2006. / Includes vita. Includes bibliographical references (leaves 166-175).

Since their introduction, the use of endosseous implant for replacements of missing teeth has increased dramatically. To date, however, there is no evidence-based answer to the important clinical question: What implant-supported prosthesis designs provide the best outcomes? Cochrane systematic reviews have been used to critically assess scientific literature, to answer a wide array of questions. This approach was used to focus on implant-related treatment outcomes, including patient-based outcomes. Data showed that in most cases clinical and patient-mediated outcomes did not differ significantly from one another regardless of the prosthesis used. However, long-term prognosis of implant-supported overdentures using magnet attachments may produce inferior outcomes when compared to other attachments. In this dissertation it was shown that long-term results following immediate loading of endosseous implants with overdentures were successful based on biological and clinical parameters, cost to patient, and patient-based outcomes. Moreover, it was noted that well-designed clinical trials evaluating efficacy of immediate loading with fixed prostheses are uncommon. Furthermore, a parallel randomized controlled clinical trial focusing on this issue was carried out. In this trial, the author investigated the effects of immediate and delayed loading of implants with mandibular fixed prostheses. The implant-related outcomes underscore that even when implants are loaded during the healing period (i.e. immediate loading), successful osseointegration can be achieved and maintained. Patients’ satisfaction and oral health-related quality of life indicated that the two loading schemes addressed patient’s need equally.

The purpose of this study was to determine the impact of insertion angle of orthodontic mini screws on the stability and resistance to movement of the mini screw, and on the peri-implant interface. Three orthodontic mini screws were placed in each tibia of six New Zealand white rabbits bilaterally (N=36), with randomized angulation (65° away, 65° toward, or 90° to the direction of applied force). After two weeks, two orthodontic mini screws within each tibia were loaded with a 200g Nitinol closed-coil spring for up to 14 days. No statistically significant differences were found among the variably angulated loaded and unloaded orthodontic mini screws in the amount of movement or change in angulation demonstrated over the experimental period. Micro CT analysis revealed no clinically significant differences in the amount of cortical bone-to-implant contact. Mini screw placement angulation seems to have minimal impact on stability and migration of orthodontic mini screws over time.

The purpose of this study was to determine the impact of insertion angle of orthodontic mini screws on the stability and resistance to movement of the mini screw, and on the peri-implant interface. Three orthodontic mini screws were placed in each tibia of six New Zealand white rabbits bilaterally (N=36), with randomized angulation (65° away, 65° toward, or 90° to the direction of applied force). After two weeks, two orthodontic mini screws within each tibia were loaded with a 200g Nitinol closed-coil spring for up to 14 days. No statistically significant differences were found among the variably angulated loaded and unloaded orthodontic mini screws in the amount of movement or change in angulation demonstrated over the experimental period. Micro CT analysis revealed no clinically significant differences in the amount of cortical bone-to-implant contact. Mini screw placement angulation seems to have minimal impact on stability and migration of orthodontic mini screws over time.

Since their introduction, the use of endosseous implant for replacements of missing teeth has increased dramatically. To date, however, there is no evidence-based answer to the important clinical question: What implant-supported prosthesis designs provide the best outcomes? Cochrane systematic reviews have been used to critically assess scientific literature, to answer a wide array of questions. This approach was used to focus on implant-related treatment outcomes, including patient-based outcomes. Data showed that in most cases clinical and patient-mediated outcomes did not differ significantly from one another regardless of the prosthesis used. However, long-term prognosis of implant-supported overdentures using magnet attachments may produce inferior outcomes when compared to other attachments. In this dissertation it was shown that long-term results following immediate loading of endosseous implants with overdentures were successful based on biological and clinical parameters, cost to patient, and patient-based outcomes. Moreover, it was noted that well-designed clinical trials evaluating efficacy of immediate loading with fixed prostheses are uncommon. Furthermore, a parallel randomized controlled clinical trial focusing on this issue was carried out. In this trial, the author investigated the effects of immediate and delayed loading of implants with mandibular fixed prostheses. The implant-related outcomes underscore that even when implants are loaded during the healing period (i.e. immediate loading), successful osseointegration can be achieved and maintained. Patients’ satisfaction and oral health-related quality of life indicated that the two loading schemes addressed patient’s need equally.

Thèse d'exercice : Médecine. Médecine générale : Université de Nantes : 2003. / Bibliogr. f. 86-89 [53 réf.].