Impact of Augmented Bone Quality on Success of Bicon Short Implants- FE Study PDF Download
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Author: Igor Linetskiy
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Languages : en
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Bicon short implants have successfully proven themselves in the maxillary molar region with insufficient bone height and poor bone quality. To improve crestal bone healing, autogenous bone is placed in the gap between implant neck and implant bed. But even for such approach, the quality of the augmented bone is not fully predictable, though cortical bone strength is the key criterion of implant success. Finite element (FE) method allows precise analysis of this complex biomechanical system. The aim of this study was to evaluate the prospect of different-sized short plateau implants placed in atrophic posterior maxilla depending on the degree of augmented bone quality under oblique functional loading. 5.0 mm length and 4.0 (N), 5.0 (M), 6.0 (W) mm diameter Bicon SHORT u00ae implants were selected for this comparative study. Their 3D models were placed crestally in twelve posterior maxilla segment models with type III bone. They were designed using CT images in Solidworks 2016 software with 1.0 mm crestal/sinus cortical and 4.0 mm cancellous bone layers. Each model geometry was 10u00d730u00d719 mm. Implant and bone were assumed as linearly elastic and isotropic. Elasticity moduli of cortical/cancellous bone were 13.7/1.37 GPa. Four degrees of augmented bone quality were simulated: 100% (E1=13.7 GPa), 75% (E2=10.3 GPa), 50% (E3=6.85 GPa) and 25% (E4=3.43 GPa). Bone-implant assemblies were analyzed in FE software Solidworks Simulation. 4-node 3D FEs were generated with a total number of up to 4,040,000. 120.92 N mean maximal oblique load (molar area) was applied to the center of 7.0 mm abutment. Von Mises equivalent stress (MES) distributions were studied to determine the areas of bone overload. Analysis of MESs distributions in cortical bone has showed that their maximal magnitudes were found in crestal area. The spectrum of maximal MESs in augmented bone was between 9.5 MPa (W,E4) and 37 MPa (N,E1). They were influenced by implant diameter and augmented bone quality. MES reduction due to diameter increase from 4.0 to 6.0 mm was 52.7, 54.5, 55.4 and 54.8% for E1, E2, E3 and E4 bone quality. MES reduction due to two-fold augmented bone quality decrease (E1 versus E3) was 24.3, 30.2 and 28.6% for N, M and W implants. However, reduction of augmented bone quality caused significant overload of cancellous bone (5-17 MPa). Only for E1 bone, maximal MES in cancellous bone was approximately 5-7 MPa. In all other scenarios, maximal MES substantially exceeded 5 MPa strength of cancellous bone. N implants were found to be the most susceptible to the quality of augmented bone: E1 to E4 bone quality reduction has led to 126 and 82% MES rise for N and W implants. Under mean maximal functional loading, sufficient influence of augmented bone quality on crestal bone-implant interface was established. However, crestal bone overload is highly unlikely because MESs were found to be lesser than 100 MPa ultimate bone strength. Contrarily, E2-E4 bone quality scenarios are critical from the viewpoint of cancellous bone overload and implant failure. Placement of wider implant allows to decrease this risk.
Author: Igor Linetskiy
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ISBN:
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Languages : en
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Book Description
Bicon short implants have successfully proven themselves in the maxillary molar region with insufficient bone height and poor bone quality. To improve crestal bone healing, autogenous bone is placed in the gap between implant neck and implant bed. But even for such approach, the quality of the augmented bone is not fully predictable, though cortical bone strength is the key criterion of implant success. Finite element (FE) method allows precise analysis of this complex biomechanical system. The aim of this study was to evaluate the prospect of different-sized short plateau implants placed in atrophic posterior maxilla depending on the degree of augmented bone quality under oblique functional loading. 5.0 mm length and 4.0 (N), 5.0 (M), 6.0 (W) mm diameter Bicon SHORT u00ae implants were selected for this comparative study. Their 3D models were placed crestally in twelve posterior maxilla segment models with type III bone. They were designed using CT images in Solidworks 2016 software with 1.0 mm crestal/sinus cortical and 4.0 mm cancellous bone layers. Each model geometry was 10u00d730u00d719 mm. Implant and bone were assumed as linearly elastic and isotropic. Elasticity moduli of cortical/cancellous bone were 13.7/1.37 GPa. Four degrees of augmented bone quality were simulated: 100% (E1=13.7 GPa), 75% (E2=10.3 GPa), 50% (E3=6.85 GPa) and 25% (E4=3.43 GPa). Bone-implant assemblies were analyzed in FE software Solidworks Simulation. 4-node 3D FEs were generated with a total number of up to 4,040,000. 120.92 N mean maximal oblique load (molar area) was applied to the center of 7.0 mm abutment. Von Mises equivalent stress (MES) distributions were studied to determine the areas of bone overload. Analysis of MESs distributions in cortical bone has showed that their maximal magnitudes were found in crestal area. The spectrum of maximal MESs in augmented bone was between 9.5 MPa (W,E4) and 37 MPa (N,E1). They were influenced by implant diameter and augmented bone quality. MES reduction due to diameter increase from 4.0 to 6.0 mm was 52.7, 54.5, 55.4 and 54.8% for E1, E2, E3 and E4 bone quality. MES reduction due to two-fold augmented bone quality decrease (E1 versus E3) was 24.3, 30.2 and 28.6% for N, M and W implants. However, reduction of augmented bone quality caused significant overload of cancellous bone (5-17 MPa). Only for E1 bone, maximal MES in cancellous bone was approximately 5-7 MPa. In all other scenarios, maximal MES substantially exceeded 5 MPa strength of cancellous bone. N implants were found to be the most susceptible to the quality of augmented bone: E1 to E4 bone quality reduction has led to 126 and 82% MES rise for N and W implants. Under mean maximal functional loading, sufficient influence of augmented bone quality on crestal bone-implant interface was established. However, crestal bone overload is highly unlikely because MESs were found to be lesser than 100 MPa ultimate bone strength. Contrarily, E2-E4 bone quality scenarios are critical from the viewpoint of cancellous bone overload and implant failure. Placement of wider implant allows to decrease this risk.
Author: Larisa Linetska
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Languages : en
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It was repeatedly proven that implant design, bone quality and quantity significantly influence the functional load transfer. Posterior maxilla usually offers low available bone quality and quantity, so short implants are often used in edentulism treatment. Bone strains are major stimuli of bone turnover, but their high magnitudes result in implant failure. Numerical simulation is usually applied to correlate bone and implant parameters with bone strain spectrum and evaluate implant prognosis.The aim of the study was to evaluate the impact of short plateau implants and posterior maxilla bone quality on strain level in adjacent bone to predict implant success.Four Bicon short implants with 4.5 (N), 6.0 (W) mm diameter and 5.0 (S), 8.0 (L) mm length were selected for this numerical analysis. Their 3D models were inserted in 24 posterior maxilla segment models with types III and IV bone, 1.5 (A), 1.0 (B) and 0.5 (C) mm crestal cortical bone thickness. These models were designed in Solidworks 2016 software. Bone and implant materials were assumed as linearly elastic and isotropic. Young modulus of cortical bone was 13.7 GPa, cancellous bone u2013 1.37/0.69 GPa (type III/IV). Numerical analysis of bone-implant models was carried out in FE software Solidworks Simulation. A total number of 3D FEs was up to 3,590,000. 120.92 N mean maximal oblique load (molar area) was applied to the center of 7 Series Low 0u00b0 abutment. First principal strain (FPS) distributions were analyzed according to the concept of u201cminimum effective strain pathologicalu201d (MESp) by Frost. Maximal FPSs were correlated with 3000 microstrain MESp to evaluate implant prognosis.350u20267500 microstrain maximal FPSs were found in the cortical-cancellous bone interface in the vicinity of the first fin. Critical FPSs (>3000 microstrain) were observed for N implants in IV,B/C,S/L, III,B/C,S, III,C,L scenarios. For W implants, critical FPSs were found only in IV,B/C,S scenarios. Favorable FPSs (350u20263000 microstrain) were calculated in vicinity of W implants for all scenarios excluding IV,B/C,S. For N implants, favorable FPSs were observed for III,A,S/L, III,B,L. Implant diameter increase (4.5 vs. 6.0 mm) have led to 64/54/52, 78/68/70, 32/36/39, 50/53/55% FPS reduction for 1.5/1.0/0.5 mm cortical bone and III,S, III,L, IV,S, IV,L scenarios. FPS magnitudes were found sensitive to bone quality: FPS reduction in type III bone relative to type IV was -14/22/36, -95/16/39, 40/44/50, 13/44/59% for 1.5/1.0/0.5 mm and N,S, N,L, W,S, W,L scenarios.Bone strains were influenced by implant dimensions, cortical bone thickness and bone quality. 4.5u00d75.0 mm implant was recommended only for types III/IV bone and 1.5 mm cortical bone thickness, while 4.5u00d78.0 mm implant - for types III/IV bone and 1.5/1.0 mm cortical bone thickness. 6.0 mm diameter implants caused positive bone turnover for all but one scenario (6.0u00d75.0 mm implant, type IV bone, 0.5 mm cortical bone). Clinicians should consider these findings in planning of short plateau implants.
Author: Larisa Linetska
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Languages : en
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Bone loss is the most essential cause of dental implant failure. Comparing to the conventional implants, short implants may fail more rapidly because of their reduced length, especially in case of crestal placement. 0.2 mm mean annual bone loss was recommended as a criterion for implant success. Due to bone loss, even under physiological functional loading, bone overload may occur, which, in turn, provokes complementary bone loss. These processes significantly worsen implant long-term prognosis.The aim of this study was to evaluate and compare load-carrying capacities of the spectrum of fully and partially osseointegrated Bicon short implants to establish their prognosis in posterior maxilla under oblique functional loading.The concept of ultimate functional load (UFL) was proposed (Demenko et al., 2011) to compare load-carrying capacities of fully and partially osseointegrated (0.2 mm annual bone loss) 5.0 (S), 6.0 (M) and 8.0 mm (L) length and 5.0 mm diameter Bicon SHORTu00ae implants. Their 3D models were placed crestally and bicortically in corresponding posterior maxilla segment models with type III bone. They were designed in Solidworks 2016 software and had 1.0 mm cortical crestal and sinus bone layers. Implant and bone were assumed as linearly elastic and isotropic. Elasticity moduli of cortical/cancellous bone were 13.7/1.37 GPa. Bone-implant assemblies were analyzed in FE software Solidworks Simulation. 4-node 3D FEs were generated with a total number of up to 2,532,000. 120.92 N oblique load was applied to the center of 7.0 mm abutment. Von Mises stresses (MESs) were evaluated for bone-implant assemblies to determine UFL magnitudes for fully and partially osseointegrated implants and compare them.Maximal MESs for fully osseointegrated implants (26u202631 MPa) were found on the surface of crestal cortical bone. For partially osseointegrated implants they were discovered in migrating critical points inside crestal cortical bone (27u202632 and 41u202646 MPa for 0.2 and 1.0 mm bone loss). For fully osseointegrated implants, UFL magnitudes were 396u2026465 N. For partially osseointegrated implants and 0.2 bone loss, UFL magnitudes were 377u2026447 N, while for 0.4 mm u2013 356u2026417 N, for 0.6 mm u2013 327u2026366 N, for 0.8 mm u2013 314u2026356 N, and for 1.0 mm u2013294u2026336 N. So, after 5 years in function (1.0 mm bone loss), the following reduction of implant load-carrying capacity was determined: 26, 27 and 28% for S, M and L implants. Thus, all UFL magnitudes were much higher than mean maximal functional loading (120.92 N). Furthermore, for all scenarios, UFL magnitudes were above 275 N maximal functional loading for molar area. Finally, the difference between UFL magnitudes for S and M implants was approximately 5%. Short implant prognosis in terms of gradual bone loss is of crucial importance in implant dentistry. Studied Bicon SHORTu00ae implants were found moderately sensitive to bone loss, at least for 5 years in function and 1.0 mm cortical bone thickness. They were also capable to withstand 275 N maximum functional loading for molar area. Their load-carrying capacity was not substantially dependent on implant length, at least within 5u20268 mm, so this extends their application, especially in bone loss.
Author: Larisa Linetska
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Languages : en
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Short finned implants are often applied in critical cases of edentulous posterior maxilla with no available bone for subcrestal implant placement. Resulting higher stresses in crestal cortical bone lead to its overload and subsequent implant failure. Finite element (FE) method provides biomechanical evaluation of bone-implant structures and influence of bone quality and implant parameters on bone stresses.The aim of the study was to evaluate the impact of crestal placement of short finned implants on stress magnitudes in atrophic posterior maxilla under oblique functional loading to predict bone overload and implant failure.Four Bicon Integra-CPu2122 implants with 4.5, 6.0 mm diameter and 5.0, 8.0 mm length were selected for this evaluation. Their 3D models were placed in 12 posterior maxilla segment models with type IV bone, 1.5, 1.0 and 0.5 mm crestal cortical bone thickness. These models were designed using CT images in Solidworks 2016 software. Implant and bone were assumed as linearly elastic and isotropic. Elasticity modulus of cortical bone was 13.7 GPa, cancellous bone u2013 0.69 GPa. Bone-implant assemblies were analyzed in FE software Solidworks Simulation. 4-node 3D FEs were generated with a total number of up to 2,820,000. 120.92 N mean maximal oblique load (molar area) was applied to the center of 7 Series Low 0u00b0 abutment. Von Mises equivalent stress (MES) distributions in surrounding bone were studied to determine the areas of bone overload with magnitude >100 MPa in cortical bone.Maximal magnitudes of MESs were found in crestal cortical bone. The spectrum of maximal MESs was between 14.0 and 47.0 MPa. The highest MESs were found for 4.5u00d75.0 mm implant, while the smallest magnitudes were determined for 6.0u00d78.0 mm implant. For tested implants, maximal MES magnitudes were significantly influenced by cortical bone thickness and implant dimensions: for 0.5, 1.0 and 1.5 mm cortical bone thickness and diameter increase from 4.5 to 6.0 mm, MES drop was 48, 47, 43% for 5.0 mm length implants, while for 8.0 mm length implants it was 48, 48, 46%. In 0.5 mm cortical bone thickness, maximal MESs varied within 15-17% range. For 4.5/6.0 mm diameter implants, bone thickness increase from 0.5 to 1.5 mm corresponded to 43/35% MES drop for 5.0 mm length implants and 33/30% - for 8.0 mm length implants, while two-fold bone thickness increase from 0.5 to 1.0 mm corresponded to 21/19% MES drop for 5.0 mm length implants and 15/15% - for 8.0 mm length implants.The study enhances perception of bone stress issues in the posterior maxilla relative to cortical bone thickness. Evaluated finned implants have not exceeded 100 MPa ultimate cortical bone strength. For 1.5 mm cortical bone thickness, no sensitivity to implant length was found. This FE study approves the finned implants clinical success in posterior maxilla due to their low susceptibility to poor bone quality. It provides a rationale for appropriate implant selection.
Author: Igor Linetskiy
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Languages : en
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Short implants are indispensable in posterior maxilla with insufficient bone height. Implant design, bone quality and degree of bone loss predetermine safe functional load transfer to adjacent bone. Adequate bone strains are key stimuli of bone turnover, but their extreme magnitudes lead to implant failure. Computer simulation allows to correlate bone and implant parameters with bone strain spectrum and to evaluate implant perspective.The aim of the study was to evaluate the impact of plateau implants and bone quality on strain levels in adjacent bone at several levels of bone loss to assess implant prognosis.Cortical and cancellous bone first principal strains (FPSs) were selected to evaluate bone turnover around fully and partially osseointegrated 4.5 (N), 5.0 (M) and 6.0 mm (W) diameter and 5.0 mm length Bicon SHORTu00ae implants at five levels of bone loss from 0.2 to 1.0 mm. Implant 3D models were placed crestally in corresponding posterior maxilla segment models with type III bone and 1.0 mm cortical crestal and sinus bone layers. The models were designed in Solidworks 2016 software. All materials were assumed as linearly elastic and isotropic. Elasticity modulus of cortical bone was 13.7 GPa, cancellous bone u2013 1.37 GPa. Bone-implant assemblies were analyzed in FE software Solidworks Simulation. A total number of 4-node 3D FEs was up to 3,450,000. 120.92 N mean maximal oblique load (molar area) was applied to the center of 7 Series Low 0u00b0 abutment. Maximal FPSs were correlated with 3000 microstrain minimum effective strain pathological (MESp) to evaluate bone turnover around the implants.Maximal FPSs for osseointegrated implants (1800u20263270 microstrain) were found in the cancellous bone at the first fin edge. For implants with bone loss, they were observed at the same location and were significantly dependent on bone loss level (2140u20263600, 2300u20264100, 2800u20264900, 3500u20265900 and 4200u20267000 microstrain for 0.2, 0.4, 0.6, 0.8 and 1.0 mm bone loss). Maximal FPSs were also substantially dependent on implant diameter: diameter increase from 4.5 to 6.0 mm have led to 41, 44, 43, 41, 40% FPS decrease for 0.2, 0.4, 0.6, 0.8 and 1.0 mm bone loss. Comparing to the osseointegrated implants, the following FPS increase on five bone loss levels was determined: for N implants it was 10, 25, 50, 80 and 114%, for M implants u2013 12, 32, 62, 92, 131%, for W implants u2013 19, 28, 56, 94 and 133%.Bone turnover was found to be significantly influenced by implant diameter and bone loss level. 4.5 mm diameter implant is not recommended for type III bone because bone strains exceed 3000 microstrain threshold even for the osseointegrated implant. 6.0 mm diameter implant caused positive bone turnover balance for up to 0.6 mm bone loss, while 5.0 mm u2013 only for up to 0.3 mm bone loss. Clinicians should consider these findings in treatment with short plateau implants.
Author: Igor Linetskiy
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Languages : en
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Implant prognosis is predetermined by stresses in the bone-implant interface. Plateau implants are considered to be highly successful since they reduce bone stress concentrations. For cases with lack of bone height, crestal placement remains a reasonable alternative. Otherwise, subcrestal placement of short implants is advised since it is considered as a crucial factor in preservation of crestal bone. For such scenario, bone biomechanical state is directly dependent on implant insertion depth. The aim of the study was to compare the impact of crestal or subcrestal short plateau implant placement in different bone quality conditions on peri-implant bone stresses and to assess implant prognosis under 120.92 N mean maximal oblique functional loading.5.0u00d75.0 mm Bicon Integra-CPu2122 implant was selected for this comparative study. Its 3D models were placed in four posterior maxilla models with types III and IV bone with 1.0 mm cortical bone thickness. Different insertion depths were simulated: the implant neck was in crestal (C) and -1, -2 and -3 mm subcrestal (S1, S2, S3) positions. All materials were assumed to be linear elastic and isotropic. Elastic moduli of cortical, type III/IV cancellous bone and implants were set to 13.7, 1.37/0.69 and 114 GPa, and Poissonu2019s ratio was 0.3 for all materials. Finite element (FE) models were analyzed in Solidworks Simulation software. 4-node 3D FEs were generated with a total number of up to 3,570,000. 120.92 N mean maximal oblique load (molar area) was applied to the center of 7.0 mm abutment. Von Mises equivalent stress (MES) distributions in surrounding bone were studied to determine the areas of bone overload with magnitude >100 MPa in cortical and >5 MPa in cancellous bone.Maximal MES magnitudes for all scenarios were found at the implant neck. For C scenario, maximal MES magnitudes were found in crestal cortical bone: 21/28 MPa (type III/IV bone). Maximal MES magnitudes in cancellous bone were approximately 5 MPa for both bone types. For S1, S2 and S3 scenarios, since there was no contact between implant and cortical bone, maximal MES magnitudes were located in cancellous bone at the implant neck. For S1 scenarios they were 18u202620 MPa, for S2 and S3 scenarios they were 13u202614 MPa, for both bone quality types. Another critical MES area was located at the implant root: for C scenario, maximal MES magnitudes were 2 MPa for both bone quality types, for S1 scenario they were 2.5/3.5 MPa, for S2 u2013 3.5/4.0 MPa and for S3 u2013 7/10 MPa (for type III/IV bone).It was found that 5.0u00d75.0 mm Bicon Integra-CPu2122 implant in crestal placement generated safe bone MESs and offered favorable clinical prospect. For all subcrestal scenarios, the implant caused exceeding MESs in cancellous bone due to absence of interface between the implant and cortical bone. However, the tested Bicon implant showed low susceptibility to bone quality worsening at studied levels of subcrestal placement. This finding confirms positive clinical experience of Bicon plateau implants.
Author: Young-Jun Lim
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Languages : en
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Background : Short implants are considered to be the simpler and more effective alternative to complicated bone graft surgery in clinical situations with reduced alveolar bone height. But, a considerable number of clinicians still hesitate to use short implants questioning about their prognoses mainly due to the reduced contact area between the bone and implant and unfavorable crown to implant ratio compared to longer implants. Aim : The aim of the study is to evaluate the clinical and radiographic outcomes of short implants supporting fixed prostheses in posterior regions. Methods : A retrospective study design was adopted. 69 short implants(intra-bony length u2264 8 mm) supporting fixed prostheses in posterior regions of 56 patients were included. The implant success rate and periimplant marginal bone loss were evaluated. The effects of associated factors on the implant performance were analyzed. Results : A total of 3 implants failed. 2 implants were lost before loading and 1 implant was lost at 7 months after loading. The mean follow up was 30.1 months(SD=11.8 months). Success rate was 95.7% and 94.6% for the implant and patient-based analysis respectively. The average marginal bone loss after 1 year of follow-up was 0.02 u00b1 0.16 mm at mesial and 0.03 u00b1 0.14 mm at distal aspect. No relationship was observed between the studied variables and the marginal bone loss. Conclusions: High survival rates for short implants in posterior regions could be achieved with minimal marginal bone loss in this study. Within the limits of the short term follow up, a short implant (u2264 8 mm ) may be considered as a predictable treatment modality for posterior region with reduced bone height.
Author: Miguel Angel Gonzáles-Ascar
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Languages : en
Pages : 96
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Author: KArin Gisel Bedoya
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Languages : en
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The use of short implants has gained popularity in the last years, since they have demonstrated high long-term survival and success rates. Also, they allow to reduce treatment time, morbidity and costs compared to bone regeneration procedures. Adequate primary stability and osseointegration are of extreme importance for long-term success of implant therapies.The aim of this study was to assess the relationship between insertion torque (primary stability), premature osseointegration failure and bone loss in patients with short morse taper implants after a 1-year follow-up.6-8mm of vertical bone and 6mm of horizontal bone, evaluated by tomographic examination, were included. A total of 20 morse taper 4 and 5mm in diameter and 5 and 6mm in length dental implants were installed in 11 patients. During implant placement procedures, insertion torques were recorded using a torque wrench and implants were left submerged. After 6 months, second-stage surgeries were performed, signs of premature osseointegration failures evaluated (absence of mobility), provisional crowns delivered and x-rays taken. 1-year after loading, control x-rays were taken. Bone levels were measured in x-rays from the implant platform to marginal bone using ImageJ 1.52d analysis software (National Institutes of Health, Bethesda, USA). Loading and follow-up x-rays were compared to assess the amount of bone loss. Data collected was analyzed using different statistical tests in the SPSS software (IBM Statistics version 21).The mean follow-up time after implant placement was 18.75 u00b1 7 months. Three implants were excluded (15%), two due to mechanical failures and one due to biological failures. Mean values for mesial bone measurements at loading (0.95u00b1 0.74) and at control x-rays (0.88 u00b1 0.83), and for distal bone levels at loading (1.12u00b1 0.92) and at control x-rays (1.08 u00b1 0.91) were used to calculate the amount of bone loss in mesial (0.146) and distal sites (0.326), respectively. Correlation values between insertion torque, mesial (r=-0.240) and distal bone loss (r=0.127) were calculated, as well as for insertion torque and osseointegration (r=0.291).Initial and follow-up values for bone loss showed no statistical differences, thus short implants showed stable bone levels after one year of installation. No relation between insertion torque and bone loss nor insertion torque and osseointegration was found, meaning that initial torque has no direct influence on the amount of bone loss and does not predict osseointegration failures. This study demonstrates the success of short implants in a short-term period.
Author: Khadijeh Al-Abedalla
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Languages : en
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"Dental implants are a successful and predictable treatment for partially and fully edentulous patients. However, they require sufficient volume of healthy bone for stabilization and long-term success. Lack of bone volume prevents implant placement and it is usually due to many reasons such as tooth loss, trauma or diseases. A variety of surgical techniques are available for alveolar bone rehabilitation. However, bone onlay augmentation is the most reliable and commonly used one. Different bone grafts can be used for bone onlay augmentation. Autograft onlays are currently the gold standard onlay grafts because of their osteoinductive, osteoconductive, and osteogenic properties. However, due to their limitations and drawbacks, some of which are considered severe, alternative materials have been developed including allografts, xenografts, and alloplastic bone grafts. Although previous reports demonstrated high success rate of implants placed in bone augmented with allograft onlays, evidence based articles are still needed to prove these results. On the other hand, due to some concerns about the antigenicity of allografts and xenografts onlays, synthetic materials such as monetite onlays have been developed for bone augmentation in vivo. Nonetheless, these synthetic onlays were still inferior to autograft onlays. Therefore, this thesis has two main objectives. Firstly, to clinically assess the performance of freeze-dried allograft in bone augmentation and implant treatment. Secondly, to improve the capability of synthetic onlays in bone regeneration, then assess their performance in bone augmentation and implant treatment in vivo.By conducting two cohort studies: clinical and histological, we proved that bone augmented with allograft onlays is similar to native alveolar bone in terms of bone quality and quantity. Moreover, we showed that implants placed in bone augmented with allograft onlays have rates of success and survival similar to implants placed in either bone augmented with autograft onlays or native alveolar bone. We also demonstrated that customizing the morphology of monetite synthetic onlays according to the metabolic activity of the recipient site in vivo can enhance bone formation, monetite resorption, bone height and implant osseointegration.Our results showed that allograft onlays could replace autograft onlays with similar clinical results. It was also observed that designing the macropore geometry according to the bone metabolic activity was a key parameter in increasing the volume of bone augmented within synthetic monetite onlays. However, further studies are needed to optimize the osteoconductivity of these synthetic onlays in order to be able to replace the autograft and allograft onlays in the future." --
