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Bone Response (bone + response)
Selected AbstractsBone Response Inside Free-Form Fabricated Macroporous Hydroxyapatite Scaffolds with and without an Open MicroporosityCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2007Johan Malmström DDS ABSTRACT Background:, The technique of free-form fabrication enables the production of controlled macroporous geometry inside ceramic scaffolds. Using scaffolds with identical macropore design makes it possible to study a relevant biological response linked to other specific changes of the material. Purpose:, This study investigates the role of open micropores in hydroxyapatite (HA) scaffold during early bone healing to quantitatively ascertain whether microporosity in otherwise identical macroporous HA scaffolds can influence the bone response in rabbit tibia and femur at 6 weeks. Materials and Methods:, HA scaffolds (Ø: 3.8 mm) with and without microporosity were randomly installed in both cortical and trabecular bone sites of New Zealand White rabbits. The animals were sacrificed 6 weeks after surgery. Ground sections obtained from en bloc tissues containing scaffold and recipient bone were subjected to histological evaluation and histomorphometric analysis. Results:, Microscopy showed elevated amounts of bone ingrowth and bone contact inside the microporous HA (mHA) group as compared with non-mHA. Conclusion:, The current study indicates that the presence of open scaffold microporosity in HA, as determined by the fabrication process, enhances the ability of ceramic scaffolds to promote bone ingrowth and bone contact. [source] Bone Response to Implant-Supported Frameworks with Differing Degrees of Misfit Preload: In Vivo Study in RabbitsCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2000Torsten Jemt DDS ABSTRACT Purpose: To study the bone response around implants placed in tibia of rabbits that supported misfitting superstructures secured with different degrees of preload. Materials and Methods: Twelve rabbits were provided with two terminal 10-mm and one intermediate 7-mm-long implant in each tibia. After an integration time of about 9 weeks, nine of the animals received one control framework each (n = 9), designed with good fit to all three implants. In the other tibia of these animals, and in both tibias in the remaining three rabbits, test frameworks (n = 15) were connected with a vertical misfit of about 1 mm to the intermediate implant. The intermediate set screws were tightened with a torque ranging from 15 Ncm to 26 Ncm in the different test frameworks. The fascia and skin was then sutured back over the implants. After a loading period of 2 to 3 weeks, the animals were sacrificed, and histomorphometric measurements were made and correlated to the different levels of preload of the central implant. Results: The mean bone-to-metal contact for the three best consecutive threads of the central implant was 40% for both test and control sites (p > .05). Compared to the other regions of the implant thread, less bone-to-metal contact was found at the tip of the test implant threads in the low preload group (p < .05). However, the same relation was not observed in the high preload group. A significant correlation was observed between increasing degree of preload in the central screw joint and increasing bone-to-metal contact, most obviously noticed at the tip of the implant thread (p < .01). Conclusions: Misfit stress levels of clinical magnitudes do not seem to jeopardize osseointegration per se. On the contrary, clinical levels of preload stress seem to significantly promote bone remodeling at the tip of the implant thread. [source] Positive Linear Growth and Bone Responses to Growth Hormone Treatment in Children With Types III and IV Osteogenesis Imperfecta: High Predictive Value of the Carboxyterminal Propeptide of Type I Procollagen,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2003Joan C Marini MD Abstract Extreme short stature is a cardinal feature of severe osteogenesis imperfecta (OI), types III and IV. We conducted a treatment trial of growth hormone in children with OI and followed linear growth velocity, bone metabolism markers, histomorphometrics, and vertebral bone density. Twenty-six children with types III and IV OI, ages 4.5,12 years, were treated with recombinant growth hormone (rGH), 0.1,0.2 IU/kg per day for 6 days/week, for at least 1 year. Length, insulin-like growth factor (IGF-I), insulin-like growth factor binding protein (IGFBP-3), bone metabolic markers, and vertebral bone density by DXA were evaluated at 6-month intervals. An iliac crest biopsy was obtained at baseline and 12 months. Approximately one-half of the treated OI children sustained a 50% or more increase in linear growth over their baseline growth rate. Most responders (10 of 14) had moderate type IV OI. All participants had positive IGF-I, IGFBP-3, osteocalcin, and bone-specific alkaline phosphatase responses. Only the linear growth responders had a significant increase in vertebral DXA z-score and a significant decrease in long bone fractures. After 1 year of treatment, responders' iliac crest biopsy showed significant increases in cancellous bone volume, trabecular number, and bone formation rate. Responders were distinguished from nonresponders by higher baseline carboxyterminal propeptide (PICP) values (p < 0.05), suggesting they have an intrinsically higher capacity for collagen production. The results show that growth hormone can cause a sustained increase in the linear growth rate of children with OI, despite the abnormal collagen in their bone matrix. In the first year of treatment, growth responders achieve increased bone formation rate and density, and decreased fracture rates. The baseline plasma concentration of PICP was an excellent predictor of positive response. [source] Bone response to different strength orthodontic forces in animals with periodontitisJOURNAL OF PERIODONTAL RESEARCH, Issue 6 2005J. A. Garat Background:, Occlusal alterations resulting from tooth movements caused by periodontitis-related bone loss are often corrected with orthodontic treatments. Although the outcome is usually satisfactory, a quantitative histomorphometric study of bone response would contribute to improving treatment planning and optimizing results. Methods and Results:, This study is a histomorphometric analysis of alveolar bone response to 51 and 75-g orthodontic forces applied to rat molars subjected to experimental periodontitis by placing a ligature around the neck of the molar during 48 h. The orthodontic device consisted of two bands with a tube welded to their palatine aspect, through which the arms of a helicoidal spring were threaded so as to exert force toward palatine. The device was placed immediately and 48 h after removing the ligatures. When applied 48 h post-removal of the ligature, both orthodontic forces caused an increase in bone volume in the periodontitis group. Conclusions:, Our study shows that application of orthodontic forces once periodontal infection has been controlled contributes to increasing alveolar bone volume, consequently improving bone quality. [source] The distribution of skeletal lesions in treponemal disease: is the lymphatic system responsible?INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 3 2002Hallie R. Buckley Abstract The differential diagnosis of bone lesions in treponemal disease is well established in palaeopathology. However, the actual mechanism responsible for the characteristic distribution of bone involvement is not as clear. Two mechanisms are proposed in the literature. Firstly, that bone lesions are the result of direct extension from the skin rash of the secondary stage of disease. Secondly, that bones situated closer to the skin are more vulnerable to local trauma and therefore more likely to elicit a subperiosteal bone response. We propose an alternative explanation for the characteristic distribution of bone lesions in treponemal disease. This explanation is based on the close association between the lymphatic and skeletal systems and the pathogenesis of treponemal disease. This paper argues that the position of the lymphatic nodes and vessels, with little soft tissue intervention between bone tissue, mirrors the characteristic pattern of skeletal involvement in treponemal disease. Copyright © 2002 John Wiley & Sons, Ltd. [source] Ovariectomy-Induced Bone Loss Varies Among Inbred Strains of Mice,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2005Mary L Bouxsein PhD Abstract There is a subset of women who experience particularly rapid bone loss during and after the menopause. However, the factors that lead to this enhanced bone loss remain obscure. We show that patterns of bone loss after ovariectomy vary among inbred strains of mice, providing evidence that there may be genetic regulation of bone loss induced by estrogen deficiency. Introduction: Both low BMD and increased rate of bone loss are risk factors for fracture. Bone loss during and after the menopause is influenced by multiple hormonal factors. However, specific determinants of the rate of bone loss are poorly understood, although it has been suggested that genetic factors may play a role. We tested whether genetic factors may modulate bone loss subsequent to estrogen deficiency by comparing the skeletal response to ovariectomy in inbred strains of mice. Materials and Methods: Four-month-old mice from five inbred mouse strains (C3H/HeJ, BALB/cByJ, CAST/EiJ, DBA2/J, and C57BL/6J) underwent ovariectomy (OVX) or sham-OVX surgery (n = 6-9/group). After 1 month, mice were killed, and ,CT was used to compare cortical and trabecular bone response to OVX. Results: The effect of OVX on trabecular bone varied with mouse strain and skeletal site. Vertebral trabecular bone volume (BV/TV) declined after OVX in all strains (,15 to ,24%), except for C3H/HeJ. In contrast, at the proximal tibia, C3H/HeJ mice had a greater decline in trabecular BV/TV (,39%) than C57BL/6J (,18%), DBA2/J (,23%), and CAST/EiJ mice (,21%). OVX induced declines in cortical bone properties, but in contrast to trabecular bone, the effect of OVX did not vary by mouse strain. The extent of trabecular bone loss was greatest in those mice with highest trabecular BV/TV at baseline, whereas cortical bone loss was lowest among those with high cortical bone parameters at baseline. Conclusions: We found that the skeletal response to OVX varies in a site- and compartment-specific fashion among inbred mouse strains, providing support for the hypothesis that bone loss during and after the menopause is partly genetically regulated. [source] Good Maintenance of Exercise-Induced Bone Gain with Decreased Training of Female Tennis and Squash Players: A Prospective 5-Year Follow-Up Study of Young and Old Starters and ControlsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2001Saija Kontulainen Abstract This prospective 5-year follow-up study of 64 adult female racquet sports players and 27 controls assessed the changes in the playing-to-nonplaying arm bone mineral content (BMC) differences to answer three questions: (1) Are training-induced bone gains lost with decreased training? (2) Is the bone response to decreased training different if the playing career has been started before or at puberty rather than after it? (3) Are the possible bone changes related to the changes in training? The players were divided into two groups according to the starting age of their tennis or squash playing. The mean starting age was 10.5 years (SD, 2.2) among the players who had started training before or at menarche (young starters; n = 36) while 26.4 years (SD, 8.0) among those players who had begun training a minimum of 1 year after menarche (old starters; n = 28). At baseline of the 5-year follow-up, the mean age of the young starters was 21.6 years (SD, 7.6) and that of old starters was 39.4 years (SD, 10.5). During the follow-up, the young starters had reduced the average training frequency from 4.7 times a week (2.7) to 1.4 times a week (1.3) and the old starters from 4.0 times a week (1.4) to 2.0 times a week (1.4), respectively. The 5-year follow-up revealed that despite reduced training the exercise-induced bone gain was well maintained in both groups of players regardless of their clearly different starting age of activity and different amount of exercise-induced bone gain. The gain was still 1.3,2.2 times greater in favor of the young starters (at the follow-up, the dominant-to-nondominant arm BMC difference was 22% [8.4] in the humeral shaft of the young starters versus 10% [3.8] in the old starters, and 3.5% [2.4] in controls). In the players, changes in training were only weakly related to changes in the side-to-side BMC difference (rs = 0.05,0.34, all NS), and this was true even among the players who had stopped training completely a minimum 1 year before the follow-up. In conclusion, if controlled interventions will confirm our findings that an exercise-induced bone gain can be well maintained with decreased activity and that the maintenance of the bone gain is independent of the starting age of activity, exercise can be recommended for preventing osteoporosis and related fractures. [source] Influence of controlled immediate loading and implant design on peri-implant bone formationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 2 2007Katleen Vandamme Abstract Aim: Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. Material and Methods: A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F -statistic model with ,=5% determined statistical significance. Results: A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. Conclusions: Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant. [source] Healing Following Cranial Trauma,JOURNAL OF FORENSIC SCIENCES, Issue 2 2008Lenore T. Barbian Ph.D. Abstract:, This paper reports on the gross appearance of the initial osseous response following cranial gunshot wounds. A total of 127 adult crania and cranial sections were analyzed for four types of bone response: osteoblastic, osteoclastic, line of demarcation, and sequestration. In general, no osteoblastic or osteoclastic response was noted during the first week. This response was followed by an increasing prevalence of expression after this time. By the sixth week postfracture both osteoclastic and osteoblastic activity was scored for 100% of the sample. Further, our observations suggest that the line of demarcation may establish the boundary between the living bone and bone not surviving the fracture. Sequestration appears to be a long-term event and was scored as present well past the eighth week of healing. The osseous expression of infection following fracture was also considered. [source] Sex differences in long bone fatigue using a rat modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 10 2006Luisa D. Moreno Abstract Stress fractures can occur because of prolonged exercise and are associated with cyclic loading. Fatigue is the accumulated damage that results from cyclic loading and bone fatigue damage is of special concern for athletes and army recruits. Existing literature shows that the rates of stress fracture for female athletes and female army recruits are higher than their male counterparts. In this study, we used an ex vivo rat model to investigate the fatigue response of female and male bones. We determined the strain versus number of cycles to failure (S/N) for each sex and found that for a certain initial strain (5,000,7,000 µ,) female bones have shorter fatigue life. To further characterize the bone response to fatigue, we also determined the creep that occurred during the fatigue test. From the creep data, for a certain strain range, female bones accumulated greater residual strains and reached the critical strain at a faster rate. In summary, this study demonstrates that female rat bones have a lower resistance to fatigue in the absence of a physiological response such as muscle fatigue or osteogenic adaptation. From these results, we hypothesized that creep was the underlying mechanism that accounted for the fast deterioration of female bones during fatigue. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1926,1932, 2006 [source] Bone response to different strength orthodontic forces in animals with periodontitisJOURNAL OF PERIODONTAL RESEARCH, Issue 6 2005J. A. Garat Background:, Occlusal alterations resulting from tooth movements caused by periodontitis-related bone loss are often corrected with orthodontic treatments. Although the outcome is usually satisfactory, a quantitative histomorphometric study of bone response would contribute to improving treatment planning and optimizing results. Methods and Results:, This study is a histomorphometric analysis of alveolar bone response to 51 and 75-g orthodontic forces applied to rat molars subjected to experimental periodontitis by placing a ligature around the neck of the molar during 48 h. The orthodontic device consisted of two bands with a tube welded to their palatine aspect, through which the arms of a helicoidal spring were threaded so as to exert force toward palatine. The device was placed immediately and 48 h after removing the ligatures. When applied 48 h post-removal of the ligature, both orthodontic forces caused an increase in bone volume in the periodontitis group. Conclusions:, Our study shows that application of orthodontic forces once periodontal infection has been controlled contributes to increasing alveolar bone volume, consequently improving bone quality. [source] Bone healing performance of electrophoretically deposited apatite,wollastonite/chitosan coating on titanium implants in rabbit tibiaeJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 7 2009Smriti Sharma Abstract Bone healing of tibial defect in rabbit model was used to evaluate a composite coating of apatite,wollastonite/chitosan on titanium implant. This coating has been developed to overcome the shortcomings, such as implant loosening and lack of adherence, of uncoated titanium implant. An electrophoretic deposition technique was used to coat apatite,wollastonite/chitosan on titanium implants. The present study was designed to evaluate the bone response of coated as compared to uncoated titanium implants in an animal model. After an implantation period of 14 (group A), 21 (group B), 35 (group C) and 42 days (group D), the bone,implant interfaces and defect site healing was evaluated using radiography, scintigraphy, histopathology, fluorescence labeling and haematology. Radiography of defect sites treated with coated implants suggested expedited healing. Scintigraphy of coated implant sites indicated faster bone metabolism than uncoated implant sites. Histopathological examination and fluorescence labeling of bone from coated implant sites revealed higher osteoblastic activity and faster mineralization. Faster bone healing in the case of coated implant sites is attributed to higher cell adhesion on electrostatically charged chitosan surfaces and apatite,wollastonite-assisted mineralization at bone,implant interfaces. Haematological studies showed no significant differences in haemoglobin, total erythrocyte and leukocyte counts, done using one way-ANOVA, during the entire study period. Our results show that AW/chitosan-coated implants have the advantages of faster bone healing, increased mechanical strength and good bone,implant bonding. Copyright © 2009 John Wiley & Sons, Ltd. [source] The effects of total hip arthroplasty on the structural and biomechanical properties of adult boneAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Joshua J. Peck Abstract The responsiveness of bone to mechanical stimuli changes throughout life, with adaptive potential generally declining after skeletal maturity is reached. This has led some to question the importance of bone functional adaptation in the determination of the structural and material properties of the adult skeleton. A better understanding of age-specific differences in bone response to mechanical loads is essential to interpretations of long bone adaptation. The purpose of this study is to examine how the altered mechanical loading environment and cortical bone loss associated with total hip arthroplasty affects the structural and biomechanical properties of adult bone at the mid-shaft femur. Femoral cross sections from seven individuals who had undergone unilateral total hip arthroplasty were analyzed, with intact, contralateral femora serving as an approximate internal control. A comparative sample of individuals without hip prostheses was also included in the analysis. Results showed a decrease in cortical area in femora with prostheses, primarily through bone loss at the endosteal envelope; however, an increase in total cross-sectional area and maintenance of the parameters of bone strength, Ix, Iy, and J, were observed. No detectable differences were found between femora of individuals without prostheses. We interpret these findings as an adaptive response to increased strains caused by loading a bone previously diminished in mass due to insertion of femoral prosthesis. These results suggest that bone accrued through periosteal apposition may serve as an important means by which adult bone can functional adapt to changes in mechanical loading despite limitations associated with senescence. Am J Phys Anthropol 2009. © 2008 Wiley-Liss, Inc. [source] Combined oral oestradiol valerate-norethisterone treatment over three years in postmenopausal women: correlation between oestrogen levels and bone mineral density sitesBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 11 2000W. Perry Consultant Endocrinologist Objective To compare trabecular and compact bone response and relationship to oestrogen status using continuous oestradiol valerate 2 mg and norethisterone 0.7 mg daily as hormone replacement and to determine the therapeutic range of 17 beta-oestradiol. Design Open label trial. Setting Independent endocrine clinic Sample One hundred and thirty-one patients were compared at point of entry and at 36 months. Methods Postmenopausal women were assessed using a Lunar dual photon and single photon bone scanner, and bone mineral density of the lumbar spine, right hip and left forearm were annually correlated with 17 beta-oestradiol and oestrone levels over three years. Total alkaline phosphatase was compared between improvers and decliners of bone mineral density. Results Significant improvement in bone mineral density (P < 0.0001) occurred at all sites except the left forearm, where bone loss was prevented. There was no correlation between oestrogen levels and bone mineral density improvements at hip sites. However, in the lumbar spine larger improvements in bone mineral density occurred in women with 17 beta-oestradiol levels > 185 pmol/L compared with those below, which were statistically significant for those with 17 beta-oestradiol levels > 248 pmol/L. Bone turnover, as quanitifed by total alkaline phosphatase measurements, was suppressed in most patients, but there were no differences in the mean alkaline phosphatase levels between the best improvers and worst decliners for lumbar spine bone mineral density. Improvers had an age mean of 5.21 years greater than decliners (P= 0.01) and a mean duration difference since the menopause of 5.1 years compared with decliners (P= 0.007). Conclusion This combined continuous preparation of hormone replacement therapy improves not only trabecular bone but prevents compact bone loss, and the data suggest that the therapeutic range of 17 beta-oestradiol is between 200 pmol/L and 350 pmol/L. [source] Clinical Experience of TiUniteÔ Implants: A 5-year Cross-Sectional, Retrospective Follow-Up StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2010Bertil Friberg DDS ABSTRACT Background: Little is known of the long-term clinical and radiographic performance of moderately rough surface implants. Purpose: The aim of the present retrospective investigation was to study two pioneer cohorts of patients, that is, the first patients to receive Brånemark System® implants with a moderately rough surface (TiUniteÔ, Nobel Biocare AB, Göteborg, Sweden) at the present clinic. TiUnite implants were inserted either in compromised bone sites in a mixed-mouth concept together with turned implants or used solely. Patients were followed up over a period of 5 years with regard to implant survival and the marginal bone response. Materials and Methods: Patients who received both implant types (mixed group) comprised 41 subjects, and the second group (TiUnite group) comprised 70 subjects. A total of 110 turned and 68 TiUnite implants were placed in the mixed group, and 212 TiUnite implants in the TiUnite group. Follow-up radiographs were obtained at prosthesis placement and at the 1- and 5-year check-ups, and examined by independent observers. Results: One turned (0.9%) and two TiUnite (2.9%) implants failed in the mixed group, and three implants (1.6%) failed in the TiUnite group, indicating no significant differences between surfaces or groups (p < .05). The mean marginal bone loss at 5 years was 0.6 mm to 0.8 mm, also indicating no significant differences for the two implant types tested in the mixed group. Conclusions: Cumulative survival rates for the two implant surfaces were favorable at 5 years, and the marginal bone loss was low and similar for both implant surfaces. [source] Bone Response Inside Free-Form Fabricated Macroporous Hydroxyapatite Scaffolds with and without an Open MicroporosityCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2007Johan Malmström DDS ABSTRACT Background:, The technique of free-form fabrication enables the production of controlled macroporous geometry inside ceramic scaffolds. Using scaffolds with identical macropore design makes it possible to study a relevant biological response linked to other specific changes of the material. Purpose:, This study investigates the role of open micropores in hydroxyapatite (HA) scaffold during early bone healing to quantitatively ascertain whether microporosity in otherwise identical macroporous HA scaffolds can influence the bone response in rabbit tibia and femur at 6 weeks. Materials and Methods:, HA scaffolds (Ø: 3.8 mm) with and without microporosity were randomly installed in both cortical and trabecular bone sites of New Zealand White rabbits. The animals were sacrificed 6 weeks after surgery. Ground sections obtained from en bloc tissues containing scaffold and recipient bone were subjected to histological evaluation and histomorphometric analysis. Results:, Microscopy showed elevated amounts of bone ingrowth and bone contact inside the microporous HA (mHA) group as compared with non-mHA. Conclusion:, The current study indicates that the presence of open scaffold microporosity in HA, as determined by the fabrication process, enhances the ability of ceramic scaffolds to promote bone ingrowth and bone contact. [source] Bone Formation at Titanium Implants Prepared with Iso- and Anisotropic Surfaces of Similar Roughness: An in Vivo StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2005Anna Göransson DDS ABSTRACT Background: Implant surface topography influences the bone response after implantation. However, the importance of surface orientation is not known. Purpose: The aim of this study was to investigate the bone tissue response and the stability of titanium implants prepared with isotropic and anisotropic surfaces of similar roughness. Materials and Methods: A total of 18 implants were divided into two groups and were inserted into the femurs of nine rabbits for 12 weeks. Confocal laser scanning microscopy was used for the topographic description to verify that the two different surfaces were modified as intended. The stability of the implants was recorded by resonance frequency (RF) measurements at insertion and at time of removal, after which the implants were evaluated histomorphometrically. Results: RF measurements showed that implant stability increased with time. However, there was no significant difference between the two different surface modifications at insertion and after 12 weeks. The histomorphometric comparison revealed no statistically significant differences in regard to either bone-to-metal contact or bone area inside the threads. Conclusion: Titanium implants prepared with isotropic and anisotropic surfaces of similar roughness integrate similarly to bone during the 3 months after implantation. [source] Bone Response to Implant-Supported Frameworks with Differing Degrees of Misfit Preload: In Vivo Study in RabbitsCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2000Torsten Jemt DDS ABSTRACT Purpose: To study the bone response around implants placed in tibia of rabbits that supported misfitting superstructures secured with different degrees of preload. Materials and Methods: Twelve rabbits were provided with two terminal 10-mm and one intermediate 7-mm-long implant in each tibia. After an integration time of about 9 weeks, nine of the animals received one control framework each (n = 9), designed with good fit to all three implants. In the other tibia of these animals, and in both tibias in the remaining three rabbits, test frameworks (n = 15) were connected with a vertical misfit of about 1 mm to the intermediate implant. The intermediate set screws were tightened with a torque ranging from 15 Ncm to 26 Ncm in the different test frameworks. The fascia and skin was then sutured back over the implants. After a loading period of 2 to 3 weeks, the animals were sacrificed, and histomorphometric measurements were made and correlated to the different levels of preload of the central implant. Results: The mean bone-to-metal contact for the three best consecutive threads of the central implant was 40% for both test and control sites (p > .05). Compared to the other regions of the implant thread, less bone-to-metal contact was found at the tip of the test implant threads in the low preload group (p < .05). However, the same relation was not observed in the high preload group. A significant correlation was observed between increasing degree of preload in the central screw joint and increasing bone-to-metal contact, most obviously noticed at the tip of the implant thread (p < .01). Conclusions: Misfit stress levels of clinical magnitudes do not seem to jeopardize osseointegration per se. On the contrary, clinical levels of preload stress seem to significantly promote bone remodeling at the tip of the implant thread. [source] Influence of surgical technique and surface roughness on the primary stability of an implant in artificial bone with different cortical thickness: a laboratory studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2010Afsheen Tabassum Abstract Objective: The aim of this biomechanical study was to assess the interrelated effect of both surface roughness and surgical technique on the primary stability of dental implants. Material and methods: For the experiment, 160 screw-designed implants (Biocomp®), with either a machined or an etched surface topography, were inserted into polyurethane foam blocks (Sawbones®). As an equivalent of trabecular bone, a density of 0.48 g/cm3 was chosen. To mimic the cortical layer, on top of these blocks short-fibre-filled epoxy sheets were attached with a thickness varying from 0 to 2.5 mm. The implant sites were prepared using either a press-fit or an undersized technique. To measure the primary stability of the implant, both the insertion and the removal torques were scored. Results: Independent of the surgical technique used, both implant types showed an increased insertion and removal torque values with increasing cortical thickness, although >2 mm cortical layer no further increase in insertion torque was observed. In the models with only trabecular bone (without cortical layer) and with a 1 mm cortical layer, both implant types showed a statistically higher insertion and removal torque values for undersized compared with the press-fit technique. In addition, etched implants showed a statistically higher insertion and removal torque mean values compared with machined implants. In the models with 2 and 2.5 mm cortical layers, with respect to the insertion torque values, no effect of either implantation technique or implant surface topography could be observed. Conclusion: The placement of etched implants in synthetic bone models using an undersized preparation technique resulted in enhanced primary implant stability. A correlation was found between the primary stability and the cortical thickness. However, at or above a cortical thickness of 2 mm, the effect of both an undersized surgical approach, as also the presence of a roughened (etched) implant surface, had no extra effect. Besides the mechanical aspects, the biological effect of undersized drilling, i.e. the bone response on the extra insertion torque forces should also be elucidated. Therefore, additional in vivo studies are needed. To cite this article: Tabassum A, Meijer GJ, Wolke JGC, Jansen JA. Influence of surgical technique and surface roughness on the primary stability of an implant in artificial bone with different cortical thickness: a laboratory study. Clin. Oral Impl. Res. 21, 2010; 213,220. doi: 10.1111/j.1600-0501.2009.01823.x [source] Effect of platelet-rich plasma on the early bone formation around Ca-P-coated and non-coated oral implants in cortical boneCLINICAL ORAL IMPLANTS RESEARCH, Issue 2 2008Dimitris Nikolidakis Abstract Objectives: The purpose of the present study was to investigate the effect of local application of platelet-rich plasma (PRP) on the early healing of cortical bone around Ti implants with two different surface configurations. Material and methods: Six goats were used in this study. PRP fractions were obtained from a venous blood sample of the goats and administered immediately before implant insertion. PRP was applied via gel preparation and installation of the gel into the implant site, or via dipping of the implants in PRP fraction before insertion. A total of 36 implants (18 non-coated and 18 Ca-P-coated) were placed into the tibial cortical bone. The animals were sacrificed at 6 weeks after implantation and implants with surrounding tissue were prepared for histological examination. Histomorphometrical variables like the percentage of implant surface with direct bone,implant contact and the percentage of new and old bone adjacent to the implant were evaluated. Results: More interfacial bone-to-implant contact was observed for all the three groups of Ca-P-coated implants and the Ti/PRP liquid group. All groups revealed similar percentages of old and new bone adjacent to the implant. Conclusions: It was concluded that the additional use of PRP did not have any effect on the early cortical bone response to the Ca-P-coated implants, while PRP in a liquid form showed a tendency to increase bone apposition to roughened titanium implants. [source] Influence of implant diameter on surrounding boneCLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2007Jeff Brink Abstract Objectives: Implant osseointegration is dependent upon various factors, such as bone quality and type of implant surface. It is also subject to adaptation in response to changes in bone metabolism or transmission of masticatory forces. Understanding of long-term physiologic adjustment is critical to prevention of potential loss of osseointegration, especially because excessive occlusal forces lead to failure. To address this issue, wide-diameter implants were introduced in part with the hope that greater total implant surface would offer mechanical resistance. Yet, there is little evidence that variation in diameter translates into a different bone response in the implant vicinity. Therefore, this study aimed at comparing the impact of implant diameter on surrounding bone. Material and methods: Twenty standard (3.75 mm) and 20 wide (5 mm) implants were placed using an animal model. Histomorphometry was performed to establish initial bone density (IBD), bone to implant contact (BIC) and adjacent bone density (ABD). Results: BIC was 71% and 73%, whereas ABD was 65% and 52%, for standard and wide implants, respectively. These differences were not statistically different (P>0.05). Correlation with IBD was then investigated. BIC was not correlated with IBD. ABD was not correlated to IBD for standard implants (r2=0.126), but it was correlated with wide implants (r2=0.82). In addition, a 1 : 1 ratio between IBD and ABD was found for wide implants. It can be concluded, within the limits of this study, that ABD may be influenced by implant diameter, perhaps due to differences in force dissipation. [source] Histological evaluation of oral implants inserted with different surgical techniques into the trabecular bone of goatsCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2007Manal M. Shalabi Abstract Objective: The aim of this study was to investigate the influence of implant surface topography and surgical technique on bone response. Material and methods: For the experiment, 48 screw-designed implants were used with two different surface finishes, i.e. machined and ,blasted, etched'. The implants were inserted into the left and right medial femoral condyle of eight goats using three different surgical approaches: press-fit (implant diameter=implant bed diamete(r), undersized (implant bed diameter The effect of maximum bite force on marginal bone loss in mandibular overdenture treatment: an in vivo studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 5 2005Frits Van Kampen Abstract: The impact of bite force on the marginal bone response around implants is a subject of debate. This study focused on the effect of maximum bite force on marginal bone levels in mandibular implant overdenture treatment. In addition, the effect of the sequence of 3 different loading conditions on marginal bone loss was evaluated in vivo. The patient population consisted of a group of 18 patients. They received 2 implants in the mandible and a new denture without attachments during the period of submerged implant healing. After second stage surgery, the denture was provided with a ball, magnet or bar-clip attachment. There was a transition of attachment type after 3 and 6 months of function. The sequence in which the attachments were used was randomised. Radiographic marginal bone loss was measured after the period of submerged implant healing and after 3, 6 and 9 months of functional implant loading. Maximum bite force measurements were obtained just prior to second stage surgery with the new denture without attachment. Bite force measurements were also obtained after 3, 6 and 9 months of loading with the implant-retained overdenture. The latter 3 values were averaged. The mean bone loss during the period of submerged healing and during functional loading was 1.7 mm (0.7 mm) and 1.3 mm (0.6 mm), respectively. A relationship between maximum bite force during the period of submerged healing or during the period of functional loading on the one hand and the amount of marginal bone loss on the other could not be demonstrated. The sequence in which the different attachment types were used did not influence the observed amount of marginal bone loss. Résumé L'impact des forces d'occlusion sur la réponse de l'os marginal autour d'implants est sujet à débat. Cette étude s'est centrée sur l'effet de la force d'occlusion maximale sur les niveaux d'os marginaux dans le traitement de prothèses mandibulaires sur implants. De plus l'effet de la séquence de trois conditions de mise en charge différentes sur la perte osseuse marginale a étéévaluée in vivo. Les patients étaient au nombre de douze. Ils avaient reçu deux implants dans la mandibule et une nouvelle prothèse sans attache durant la période de guérison lorsque les implants étaient enfouis. Après la deuxième chirurgie, la prothèse amovible a été utilisée avec une boule, un aimant ou une barre comme attache. Il y avait une transition du type d'attache après trois et six mois de mise en fonction. La séquence suivant laquelle les attaches étaient utilisées était effectuée au hasard. La perte osseuse marginale radiographique a été mesurée après la période de guérison des implants enfouis et après trois, six et neuf mois de mise en fonction. Les mesures de force d'occlusion maximale ont été obtenues juste avant la deuxième chirurgie avec la nouvelle prothèse sans attache. Les mesures de forces d'occlusion ont également été obtenues après trois, six et neuf mois de mise en charge lorsque les implants retenaient la prothèse. Les trois dernières valeurs ont été mélangées. Les pertes osseuses moyennes durant la période de guérison avec les implants enfouis et durant la charge de mise en fonction étaient respectivement de 1,7±0,7 mm et de 1,3±0,6 mm. Une relation entre la force d'occlusion maximale durant la période de guérison avec les implants enfouis ou durant la période de mise en charge fonctionnelle d'une part et la quantité de perte osseuse marginale d'autre part n'a pas pûêtre démontrée. La séquence dans laquelle les différents types d'attache ont été utilisés n'influençaient pas la quantité observée de perte osseuse marginale. Zusammenfassung Der Einfluss der Kaukraft auf die Reaktion des marginalen Knochens um Implantate wir immer wieder diskutiert. Diese Studie konzentrierte sich auf den Einfluss der maximalen Kaukraft auf das marginale Knochenniveau bei Unterkieferimplantaten und Hybridprothesen. Zusätzlich untersuchte man in vivo den Einfluss von drei Phasen mit unterschiedlichen Belastungstypen auf den marginalen Knochenverlust. Es handelte sich um eine Gruppe von 18 Probanden. Alle erhielten zwei Implantate im Unterkiefer und eine neue Prothese, während der submukösen Einheilphase der Implantate noch ohne Retentionselemente. Nach der chirurgischen Freilegung der Implantate fixierte man die Prothesen mit einem Kugelanker, einem Magneten oder einem Steg. Der Wechsel zum nächsten Retentionstyp erfolgte jeweils nach 3 bis 6 Monaten normaler Funktion der Prothesen. Die Abfolge, in welcher man die Retentionselemente einsetzte, wurde zufällig ausgewählt. Den radiologischen marginalen Knochenverlust mass man nach der submukösen Einheilphase der Implantate, sowie nach 3, 6 und 9 Monate einer funktionellen Implantatbelastung. Die maximale Kaukraft wurde genau vor der chirurgischen Freilegung der Implantate mit der neuen Prothese und ohne Attachments gemessen. Zusätzliche Messungen der Kaukraft erfolgten 3, 6 und 9 Monate nach funktioneller Belastung der implantatgetragenen Hybridprothesen. Die letzten drei Werte wurden gemittelt. Der mittlere Knochenverlust während der submukösen Einheilphase betrug 1.7 mm (0.7 mm) und während der funktionellen Belastung 1.3 mm (0.6 mm). Eine Beziehung zwischen der maximalen Kaukraft während der submukösen Einheilung oder während der funktionellen Belastung auf der einen Seite und dem marginalen Knochenverlust auf der anderen Seite konnte nicht gezeigt werden. Die Abfolge, in der die verschiedenen Retentionstypen verwendet wurden, beeinflusste das Ausmass des beobachteten marginalen Knochenverlustes nicht. Resumen El impacto de la fuerza de mordida sobre la respuesta del hueso marginal alrededor de los implantes es motivo de debate. Este estudio está enfocado sobre el efecto de la fuerza de máxima mordida en los niveles de hueso marginal en el tratamiento de sobredentadura mandibular implantosoportada. Además, se evaluó el efecto de la secuencia de 3 condiciones diferentes de carga sobre la pérdida de hueso marginal in vivo. La población de4 pacientes consistió en un grupo de 18 pacientes. Estos recibieron 2 implantes en la mandíbula y una nueva dentadura sin anclajes durante el periodo de cicatrización sumergida de los implantes. Tras la cirugía de segunda fase se suministró una dentadura con anclajes de bola, imanes o barra. Se realizó un cambio en el sistema de anclaje tras 3 y 6 meses en función. La secuencia en la que se emplearon los anclajes fue aleatoria. Se midió la pérdida de hueso marginal radiográfica tras un periodo de cicatrización sumergida y tras 3, 6 y 9 meses de carga funcional de los implantes con la sobredentadura implantosoportada. Los últimos 3 valores se promediaron. La pérdida de hueso media durante el periodo de cicatrización sumergida y durante la carga funcional fue de 1.7 mm (0.7 mm) y 1.3 mm (0.6 mm) respectivamente. No se pudo demostrar una relación entre la fuerza de máxima mordida durante el periodo de cicatrización sumergida o durante el periodo de carga funcional por un lado y la cantidad de pérdida de hueso marginal por otro. La secuencia en la que se emplearon los diferentes tipos de anclajes no influyó en la cantidad de la cantidad de pérdida de hueso marginal observado. [source] Effect of surface roughness and calcium phosphate coating on the implant/bone responseCLINICAL ORAL IMPLANTS RESEARCH, Issue 4 2000Tohru Hayakawa The influence of surface roughness and calcium phosphate (Ca-P) coating on the bone response of titanium implants was investigated. Four types of titanium implants, i.e. as-machined, grit blasted, as-machined with Ca-P sputter coating, and grit blasted with Ca-P sputter coating, were prepared. The Ca-P sputter-coating, produced by using the RF magnetron sputter technique, was rapid heat-treated with infrared radiation at 600°C. These implants were inserted into the left and right femoral condyles and the left and right tibial diaphyses of the rabbits. After implantation periods of 2 and 12 weeks, the bone,implant interface was evaluated histologically and histomorphometrically. Histological evaluation revealed no new bone formation around different implant materials after 2 weeks of implantation. After 12 weeks, bone healing was almost completed. For both tibial and femoral implants, Ca-P coated implants always showed a higher amount of bone contact than either of the non-coated implants. On the other hand, surface roughness improved only the response to implants inserted into the tibial diaphysis. On the basis of these findings, we concluded that 1) deposition of a sputtered Ca-P coating on an implant has a beneficial effect on the bone response to this implant during the healing phase, and 2) besides implant surface conditions the bone response is also determined by local implant site conditions. [source]
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