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1.
Sameh Attia Joerg Wiltfang Jörn Pons-Kühnemann Jan-Falco Wilbrand Philipp Streckbein Christopher Kähling Hans-Peter Howaldt Heidrun Schaaf 《Journal of cranio-maxillo-facial surgery》2018,46(8):1205-1210
Purpose
Ablative oncological surgery to treat head-and-neck cancer often triggers a requirement for jaw reconstruction. Modern surgical procedures using free microvascular flaps afford acceptable outcomes in terms of restoration of bony and soft tissue defects. A fibula free flap is often the preferred flap, as the bone length is considerable and a two-surgeon approach is possible. Dental implants play important roles in functional rehabilitation. Our aim was to evaluate the survival of dental implants placed in reconstructed areas after transfer of fibula tissue to the jaw.Materials and methods
We retrospectively studied 34 patients who underwent ablative tumour surgery and jaw reconstruction using osteocutaneous fibula free flaps and who then received dental implants. We evaluated implant survival and success, survival of the fibula flap, and clinical and radiographic data.Results
We included 34 patients, 23 of whom were diagnosed with squamous cell carcinoma. In total, 134 dental implants were inserted in transferred fibula bone. The cumulative implant survival rate was 81%. The survival rate of the 34 fibula flaps transplanted after surgical reconstruction was 97%.Conclusion
The insertion of endosseous implants after jaw reconstruction using vascularised fibula tissue yields successful dental rehabilitation in patients with oral cancers. 相似文献2.
Elika Madani Ralf Smeets Eric Freiwald Maryam Setareh Sanj Ole Jung Daniel Grubeanu Henning Hanken Anders Henningsen 《Journal of cranio-maxillo-facial surgery》2018,46(7):1139-1146
Purpose
The preservation of peri-implant bone is one requirement for long-term success of dental implants. The purpose of this study was to evaluate the impact of subcrestal placement on the crestal bone level of immediate versus delayed placed implants after loading.Materials and methods
In this retrospective study, data of 159 patients who received 330 implants was analyzed. Implants were placed subcrestally, crestally or supracrestally into fresh sockets or healed sites. Vertical bone level height was assessed radiographically and implants were followed up annually. The influence of patient and implant related risk factors for peri-implant bone loss was evaluated using a linear mixed model.Results
Depth of implant placement was significantly correlated with peri-implant bone loss (P = 0.001, 95% CI). Least effective loss of crestal bone was determined when implants were placed between 1 mm and 1.99 mm subcrestally. Smoking significantly enhanced the risk of peri-implant bone loss (P = 0.04, 95% CI). Immediate implant placement was not positively correlated with peri-implant bone loss (P = 0.51, 95% CI).Conclusion
Within the limits of this study, implant placement 1.08 mm subcrestally may be recommendable in order to avoid supracrestal expositions of platform-switched titanium implants over time. 相似文献3.
Sonay Temizel Friedhelm Heinemann Cornelius Dirk Christoph Bourauel Istabrak Hasan 《The Journal of prosthetic dentistry》2017,117(2):239-246.e2
Statement of problem
Conventional dental implants are not applicable in the mandibular interforaminal region if bone volume is limited. Mini-dental implants offer an alternative means of supporting mandibular overdentures in a narrow residual ridge, without additional surgery.Purpose
The purpose of this nonrandomized clinical trial was to compare the ability of mini-dental implants with that of conventional dental implants in supporting mandibular overdentures during a 2-year clinical follow-up. Bone quality, bone resorption, implant stability, and oral health were assessed radiographically.Material and methods
A total of 32 participants with edentulism were included. Twenty-two participants (99 implants) received 4 to 5 mini-dental implants (diameter: 1.8-2.4 mm; length: 13-15 mm, study group), and 10 participants (35 implants) received 2 to 4 conventional dental implants (diameter: 3.3-3.7 mm; length: 11-13 mm, control group). The selection of the participants in the study or control group was based on the available bone volume in the mandible. The selection was not randomized. The density of cortical bone thickness was measured in Hounsfield units (HU) from computed tomography data, and patients were followed for 2 years. The participants were examined 3, 6, 12, and 24 months after surgery. Primary stability immediately after the insertion of dental implants (Periotest), secondary stability 6 months after implantation, modified plaque, bleeding on probing indices, and probing depth were measured and analyzed statistically (α=.05).Results
The mean HU value 6 months after implantation in the participants who received mini-dental implants was significantly (P=.035) higher (1250 HU) than that in the participants who received conventional dental implants (1100 HU). The probing depths around the conventional dental implants (1.6 and 1.8 mm, respectively) were significantly higher than those around the mini-dental implants (1.3 and 1.2 mm, respectively) 12 and 24 months after surgery, respectively (P<.001). The mean primary and secondary stability values for conventional dental implants were ?4.0 and ?4.9, respectively. The primary and secondary stability values for the mini-dental implants were ?0.3 and ?1.4, respectively. The Periotest values of the primary (measured immediately after implant insertion) and secondary implant stabilities (measured 6 months after implant insertion) were significantly higher for the conventional dental implants than for the mini-dental implants (P<.001).Conclusions
Based on this 2-year clinical trial, patients receiving mini-dental implants had clinical outcomes similar to those of patients receiving conventional dental implants to support overdenture prostheses. 相似文献4.
Statement of problem
Dental implants can be essential in the rehabilitation of various cancer defects, but their ideal placement can be complicated by the limited dimensions of the available host bone. Surgical interventions developed to increase the amount of bone are not all predictable or successful and can sometimes be contraindicated. Short dental implants have been suggested as an alternative option in sites where longer implants are not possible. Whether they provide a successful treatment option is unclear.Purpose
The purpose of this study was to review the literature on short dental implants and assess whether they are a viable definitive treatment option for rehabilitating cancer patients with deficient bone.Material and methods
A scoping review of the literature was performed, including a search of established periodontal textbooks for articles on short dental implants combined with a search of PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Database of Systematic Reviews. A search for all literature published before June 2016 was based on the following keywords: [‘dental implants’ OR ‘dental implantation, endosseous’ OR ‘dental prosthesis, implant supported’] AND [short].Results
The minimum acceptable implant length has been considered to be 6 mm. The survival rates of short implants varied between 74% and 96% at 5 years, depending on factors such as the quality of the patient’s bone, primary stability of the implant, clinician’s learning curve, and implant surface. Short implants can achieve results similar to those of longer implants in augmented bone and offer a treatment alternative that could reduce the need for invasive surgery and associated morbidity and be safer and more economical.Conclusions
Short dental implants (6 mm to 8 mm) can be used successfully to support single or multiple fixed reconstructions or overdentures in atrophic maxillae and mandibles. The use of short dental implants lessens the need for advanced and complicated surgical bone augmentation procedures, which reduces complications, costs, treatment time, and morbidity. Short implants could be an alternative in the rehabilitation of patients with cancer. 相似文献5.
Francine Baldin Able Ivete Aparecida de Mattias Sartori Geninho Thomé Ana Cláudia Moreira Melo 《The Journal of prosthetic dentistry》2018,119(1):60-66
Statement of problem
Mandibular fixed complete-arch dental prostheses on dental implants have been benefiting patients for a long time, but problems with passive fitting between the metallic framework of the prostheses and the implants might influence its long-term success.Purpose
The purpose of this cross-sectional study of immediately loaded mandibular fixed complete-arch dental prostheses was to evaluate the survival and success rates of prostheses, the survival rates of dental implants, the occurrence of complications in the prostheses and implants, participant satisfaction, and the association between cantilever length and prosthesis complications.Material and methods
Data were collected from the participants’ records. The exposure variables were participant related (sex and age) and treatment related (number of implants and length of cantilever). The outcome variables were the survival and success of the prostheses and implants, complications, and participant satisfaction. The Fisher or chi-square tests was used for the association between 2 qualitative variables (α=.05).Results
Two hundred ninety consecutive participants (1429 implants) with a mean follow-up time of 4.4 years were included. The survival rate for the prostheses was 98.6 and the success rate was 96.6%. The implant survival rate was 99.6%. Sixty-seven participants experienced a prosthetic complication, the most common being tooth fracture. Only 2.45% (n=35) of the implants were associated with screw loosening. Of the total number of participants, 86.9% were completely satisfied with their treatment. The length of the cantilever (up to 25 mm) was not associated with complications (P>.05).Conclusions
Implant-supported mandibular fixed complete-arch dental prostheses fabricated with a passive fit technique provide successful treatment for patients with edentulism. The success and survival rates of implants and prostheses were high. Only straightforward complications were observed. Cantilever length was not associated with complications. 相似文献6.
Guillermo de la Rosa Castolo Sonia V. Guevara Perez Pierre-Jean Arnoux Laurent Badih Franck Bonnet Michel Behr 《The Journal of prosthetic dentistry》2018,119(4):611-619
Statement of problem
Implant prosthodontics provides high-quality outcomes thanks to recent technological developments and certification procedures such as International Organization for Standardization (ISO) 14801. However, these certification tests are costly, and the result is highly uncertain as the influence of design variables (materials and structure) is still unknown. The design process could be significantly improved if the influence of design parameters were identified.Purpose
The purpose of this in vitro study was to use finite element analysis (FEA) to assess the influence of design parameters on the mechanical performance of an implant in regard to testing conditions of ISO 14801 standard.Material and methods
An endosseous dental implant was loaded under ISO 14801 testing conditions by numerical simulation, with 4 parameters evaluated under the following conditions: conditions of the contact surface area between the implant and the loading tool, length of the fixation screw, implant embedding depth, and material used for implant stiffness. FEA was used to compare the force that needed to reach the implant’s yield and fracture strength.Results
A dental implant’s fracture point can be increased by 41% by improving the contact surface area, by 20% depending on the type of material, by 4% depending on the length of the fixation screw, and by 1.4% by changing the implant embedding depth.Conclusions
FEA made it possible to evaluate 4 performance parameters of a dental implant under ISO 14801 conditions. Under these conditions, the contact surface area was found to be the major parameter influencing implant performance. This observation was validated experimentally in a fatigue test under ISO 14801 conditions. 相似文献7.
Lindsey Westover Gary Faulkner William Hodgetts Don Raboud 《The Journal of prosthetic dentistry》2018,119(1):178-184
Statement of problem
The success of implants for bone-anchored hearing aids (BAHA) relies on proper osseointegration at the bone-implant interface. Clinical evaluation of implant stability is important in prescribing loading, identifying the risk of failure, and monitoring the long-term health of the implant.Purpose
The purpose of this in vitro study was to evaluate 2 measurement systems for BAHA implant stability: the most commonly used, Osstell implant stability quotient (ISQ), and a newly developed advance system for implant stability testing (ASIST).Material and methods
BAHA implants (Oticon Medical Ponto and Cochlear BAHA Connect systems) were installed in plastic materials with adhesive to simulate implants integrated in bone with varying levels of interface stiffness. Different lengths of BAHA abutments were used with each implant specimen, and stability measurements were obtained with both the Osstell ISQ and the ASIST systems. The measurement systems were evaluated in terms of sensitivity to differences in interface stiffness and the effect of abutment length on the stability measurement. Repeated measures ANOVA followed by post hoc t tests were used for the comparisons with a Bonferroni adjusted alpha value of .05/15 = .003 to control for potential type 1 errors.Results
Changing the abutment length of a single implant installation had minimal effect on the ASIST stability coefficient, whereas large variations were observed in the Osstell implant stability quotient (ISQ). The Osstell showed a clear relationship of decreasing ISQ with increasing abutment length for both the Oticon Medical and the Cochlear implant systems. Both the ASIST and the Osstell were found to be sensitive to changes in interface properties, with the ASIST being more sensitive to these changes.Conclusions
The ASIST system is more sensitive to changes in interface properties and shows smaller variation because of changes in abutment length than the Osstell ISQ system. 相似文献8.
Olavo B. de Oliveira-Neto Fabiano Timbó Barbosa Célio Fernando de Sousa-Rodrigues Fernando José C. de Lima 《The Journal of prosthetic dentistry》2017,117(5):601-605
Statement of problem
With the increased number of published systematic reviews and in view of their wide clinical applicability, these studies must be carefully assessed before professionals begin to use their recommendations in daily practice, and above all, the methodological quality of this study design must be considered. In implant dentistry, one topic that has been arousing particular interest is the immediate placement of dental implants into infected sites.Purpose
The purpose of this systematic review was to determine the methodological quality of systematic reviews that evaluated the immediate placement of dental implants into infected sites.Material and methods
A systematic search was performed by 2 independent reviewers of PubMed, LILACS, and ISI Web of Knowledge up to March 2016. All selected articles were published in the English language. Systematic reviews of original papers that assessed the immediate placement of dental implants into infected sites were eligible for the overview. Narrative reviews, randomized clinical trials, and case reports were excluded. Methodological quality assessment was performed using A Measurement Tool to Assess Systematic Reviews.Results
Of the 5 selected systematic reviews, 3 were low methodological quality and 2 were assessed as moderate. None were high methodological quality. The first systematic review of the topic was published in 2010, and the most recent, published in 2015, was the only one that performed meta-analysis.Conclusions
The systematic reviews that assessed the immediate placement of dental implants into infected sites were assessed as low or moderate methodological quality. The topic focus remains controversial because the implant survival rate, the main outcome considered for the implant placement prognosis, presents contradictory results. 相似文献9.
Niels Christian Pausch Christoph Paul Kuhnt Dirk Halama 《Journal of cranio-maxillo-facial surgery》2018,46(10):1843-1849
Introduction
For treatment of lagophthalmos, metallic weight implants can be inserted in the upper eyelid to aid eyelid closure. Rigid and flexible implants are available. The objective of this study was to investigate the effect of implant type and patient variables on the survival of lid load implants.Materials and methods
Forty-four patients with lagophthalmos were recruited to undergo upper-eyelid weight implantation. The predictor variable was type of implant inserted (rigid or flexible). The outcome variable was survival of the inserted implant (survival or extrusion). Other study variables were demographic data (age, gender), implant features (material, weight), and other conditions, such as history of radiation. An NMLE test was used to compare implant survival, depending on implant type (flexible versus rigid). Other variables were analysed by use of a χ2 test.Results
Forty-four participants were recruited, 29 female (65.9%) and 15 male (34.1%). Forty-six implants (23 rigid implants, 50.0%; 23 flexible implants, 50.0%) were inserted (bilateral implantation in two patients). The average weight of implants used was 1.76 g (range 1.4–2.2 g). One to two years after surgery, average vertical aperture (eyelid gap) for the closed eye was 0.65 mm (range 0–4 mm). Incidence of extrusion was 15.2% (one in the rigid implant group, 2.2%; six in the flexible implant group, 13.0%). Incidence of extrusion was significantly higher for flexible implants than for rigid implants (p = 0.0273).Conclusions
The study results suggest that flexible implants are more likely to perforate the skin. The assumed advantages of the expensive chain lid weight must, therefore, be re-evaluated. 相似文献10.
Hyung Hwa Jeong Woo Shik Jeong Jong Woo Choi Seung Eun Jeong Soon Yuhl Nam Seung Ho Choi Yoon Sei Lee Hyeun A. Kim Young Jun Kim 《Journal of cranio-maxillo-facial surgery》2018,46(5):844-850
Background
A decreased flap volume can be an obstacle to proper phonation and swallowing. In this study we verified the proportion of volume decrease using 3D reconstructed images and identified the contributors to flap volume loss.Methods
We retrospectively analyzed all patients who underwent radical excision of tongue cancer and reconstructive surgery in our institution from January 2003 to October 2016. Segmentation of the DICOM images, 3D rendering of the neotongue flap, and analysis of the reconstructed images were performed using SPlanner V1® software.Results
The first postoperative imaging work-up was performed within an average of 22 days (T1). The last follow-up images were taken at an average of 6.25 months (T2). The mean flap volume at T2 was reduced to 82.99 per cent compared with T1, and flap height was reduced to 91.85 per cent, giving mean volume and height decreases of 17.01 per cent and 8.15 per cent, respectively. Neither the volume/height difference between T1 and T2 nor the flap volume/height discrepancy compared with the preoperative tongue affected speech or feeding function. The difference between the flap and preoperative tongue volumes was significantly related to the presence of complications (p = 0.0153). Initial flap volume was significantly related to the flap volume reduction (p = 0.0159).Conclusions
The mean flap volume reduction is the only factor significantly related to initial flap volume. Our realistic 3D reconstructed image and novel software enables us to more precisely predict the flap volume of the postoperative state and preoperatively evaluate the required flap size for covering defects. 相似文献11.
Hadi AL-Meraikhi Burak Yilmaz Edwin McGlumphy William Brantley William M. Johnston 《The Journal of prosthetic dentistry》2018,119(3):409-416
Statement of problem
Computer-aided designed and computer-aided manufactured (CAD-CAM) titanium and zirconia implant-supported fixed implant prostheses on 4 implants have become popular. The precision and accuracy of their interface fit has not been widely researched.Purpose
The purpose of this in vitro study was to compare the marginal fit of zirconia and titanium implant-supported screw-retained CAD-CAM complete fixed dental prostheses (CFDP) fit with a standardized cast simulating the all-on-4 implant distribution.Material and methods
Representation of an edentulous maxilla with 4 multiunit replicas embedded in sites corresponding to the positions of the maxillary first molars and canines was chosen. Multiunit abutments were digitally scanned using scan bodies and a laboratory scanner. CAD software was used to design screw-retained implant-fixed complete prostheses framework, and the file was sent to a milling machine for CAM. Titanium (n=5) and zirconia (n=5) frameworks were milled on 4 implants, and the frameworks were scanned with an industrial computed tomography (CT) scanner while applying the 1-screw test. The direct CT scans were reconstructed to generate a standard tessellation language (STL) file from the voxel data set and transported to volume graphics analysis software from which measurements were extracted. The circular mating surfaces of the corresponding framework interfaces to their representative multiunit abutment replicas on the standard were measured for implant position left maxillary canine (LMC), implant position right maxillary canine (RMC) and implant position right maxillary first molar (RMFM). In addition, color maps were generated to show the marginal discrepancy between the mating surfaces using ±0.500 mm color scale ranges.Results
The material type (zirconia or titanium) was not significant for 3D discrepancy measurements (P=.904). However, 3D discrepancy measurement values were significantly different between RMC and RMFM within each group (P<.001). The mean 3D ±SD discrepancy measurement for LMC for titanium was 48.2 ±2.6 μm. The mean ±3D discrepancy measurement for RMC for titanium was 74 ±15 μm and 84.4 ±12.1 μm for zirconia. The mean 3D discrepancy measurement for RMFM for titanium was 102 ±26.7 μm and 93.8 ±30 μm for zirconia. All 3D discrepancy measurements showed values <135 μm.Conclusions
Within the limitations of the present in vitro study, implant-supported CAD-CAM fabricated titanium and zirconia complete fixed dental prosthesis frameworks showed comparable marginal fit. Three-dimensional microgap measurements of frameworks showed clinically acceptable misfit values. Absolute passive fit was not achieved. 相似文献12.
Marcelo Coelho Goiato Henrique Rinaldi Matheus Rodrigo Antonio de Medeiros Daniela Micheline dos Santos Sandro Basso Bitencourt Aldiéris Alves Pesqueira 《The Journal of prosthetic dentistry》2017,117(5):685-689
Statement of problem
The rehabilitation of patients after a maxillectomy involves the use of an obturator to seal oral-nasal-sinus communication and to facilitate mastication, swallowing, and speech.Purpose
The purpose of this in vitro study was to evaluate different attachment systems used for implant-retained obturators at dissipation loads and under shear forces.Material and methods
Photoelastic models were fabricated with 3 external hexagon implants at the incisor, canine, and first molar regions. Subsequently, overdentures were made, and metal hooks were placed at the incisor and first molar regions to displace the prostheses in the vertical, anterior, and posterior directions, with a constant speed of 50 mm/min. A photoelastic model with an O-ring or bar-clip system was placed in a circular polariscope, and tested with a universal testing machine. The images were recorded and high-intensity fringes were counted using software. For strain gauge analysis, each strain gauge was placed horizontally at the mesial and distal sides of the implants. The registered strains were submitted to 2-way ANOVA (α=.05).Results
The O-ring showed the lowest number of high-intensity fringes in photoelastic imaging, while the strain gauge analysis showed the lowest stress values in the bar-clip group (P=.007).Conclusions
The stress around titanium implant necks was more damaging to surrounding bone, while the bar-clip attachment system had a better biomechanical performance. The bar-clip presented the lowest strain values around the dental implants and few high-intensity fringes. 相似文献13.
Shirin Allouch Henning Lünenbürger Martin Klein Kai Wermker 《Journal of cranio-maxillo-facial surgery》2018,46(12):2214-2219
Background
After orbital exenteration a facial prosthesis is a viable option for rehabilitation. The aim of this study was to evaluate implant loss and peri-implantitis of solitary orbital implants with regard to risk factors.Patients and methods
Implant loss (primary outcome) and periimplantitis (secondary outcome) were reviewed retrospectively in patients who received orbital implants between 2006 and 2015 with a minimum follow-up time of 12 months. Potential risk factors were analyzed using univariate and multivariate statistics.Results
94 patients were included with 371 inserted implants and 326 implants remaining for final analysis. At the time of last follow-up 18.1% (59/326) of the implants were lost and 3.4% showed signs of periimplantitis but were still stable in situ. Daily smoking (p = 0.016, OR = 2.1), irradiation (p < 0.001, OR = 2.8) and daily alcohol abuse (p = 0.028, OR = 3.1) had a significant effect on periimplantitis and implant loss. Combining smoking and irradiation, implant failure was 46.9% versus 15.0% in patients without these risk factors (p < 0.001, OR = 5.0). Age, tumor entity, ASA Score, anticoagulation, chemotherapy, diabetes and implant position did not show a significant correlation for implant loss or – except for age – periimplantitis. Younger patients showed a higher risk of developing periimplantitis (p = 0.011).Conclusion
Orbital prostheses retained by solitary implants provide a solid option to reconstruct facial defects. Whereas in general high implant survival can be expected, they should be carefully considered in patients with the risk factors irradiation, smoking and alcohol abuse. 相似文献14.
Waleed Elshahawy Raed Ajlouni Khaldoun Ajlouni Abdelfattah Sadakah 《The Journal of prosthetic dentistry》2018,119(3):432-436
Statement of problem
Dental implants are typically made of titanium. However, with the current systems on the market, the implant neck often shows through the gingival tissues as a black or dark gray line and/or as a grayish discoloration of the peri-implant soft tissue.Purpose
The purpose of this in vitro study was to test a new implant design. The key component of this design is the ceramic shell that covers the polished collar of the tissue-level titanium implant and masks its dark color to mimic natural dentition. The main purpose was to determine the maximum torque for fracturing the ceramic shell and compare it with clinical implant insertion torque value.Material and methods
Type 4 commercially pure titanium endosseous implants of 3 different diameters (3.3, 4.1, and 4.8 mm) were used. Porcelain was applied in 0.5-mm thickness to the polished collar of each implant. An axial-torsional universal testing machine was used to twist the implants until failure. The data (n=10) were statistically analyzed by ANOVA and the Tukey honest significant difference test (α=.05). The maximum torque for each diameter group was also compared with the optimum clinical implant insertion torque value of 35 Ncm (control) using a 1-sample t test.Results
None of the tested groups had a fractured ceramic shell. Instead, the implant carriers fractured at the maximum torque levels. Therefore, the fracture of the implant carriers was selected as the maximum (failure) torque value. A statistical difference was found for the failure torque between the 3.3-mm diameter and the other 2 diameters (P<.001) although no statistical differences were found between the 4.1-mm and 4.8-mm diameters (P=.106). A statistically significant difference was found between the failure torque of any one of the tested groups and the clinical insertion torque (P<.001).Conclusions
The ceramic shells did not fracture. Instead, the implant carriers fractured at certain torque levels. These levels were sufficiently higher than the clinical torque values. 相似文献15.
Sezgi Cinel Ersan Celik Elcin Sagirkaya Onur Sahin 《The Journal of prosthetic dentistry》2018,119(3):417-425
Statement of problem
Narrow diameter implants were developed to allow placement in narrow alveolar ridges. Clinicians may have concerns about the durability and function of such implants.Purpose
The purpose of this finite element study was to compare the stress values occurring on the implant and at the implant bone interface after the application of the static and dynamic forces on narrow diameter, titanium and titanium-zirconia implants in the maxillary and mandibular second premolar region.Material and methods
Titanium (Ti) and titanium-zirconium (Ti-Zr) narrow diameter implants (3.3 mm in diameter, 10 mm in length) were simulated in the maxillary and mandibular second premolar region, and metal-ceramic crown restorations were designed. Forces of 100 N were applied to crowns in a vertical and oblique (45-degree angle to the long axis) direction. Maximum and minimum principal stresses in the cortical and trabecular bone and the von Mises stresses and fatigue strength of the implants were evaluated with 3-dimensional finite element analysis.Results
In vertical and oblique static loading, Ti and Ti-Zr implants showed similar stress distribution within the same jaw models. However, the von Mises stresses in Ti-Zr implants were slightly higher than for Ti implants in all models. In oblique static and dynamic loading, all stresses were found higher than vertical loading, and fatigue failure results were found to be more critical than vertical forces.Conclusions
Based on a numerical simulation, Ti and Ti-Zr alloys can be used successfully as narrow diameter implants in the second premolar area. 相似文献16.
Wenzhi Niu Penglai Wang Shaoyue Zhu Zongxiang Liu Ping Ji 《The Journal of prosthetic dentistry》2017,117(1):34-40
Statement of problem
Whether microthreads in the crestal portion can reduce the amount of marginal bone loss (MBL) around implants has not yet been determined.Purpose
The purpose of this systematic review was to investigate the marginal bone loss around dental implants with and without microthreads in the neck.Material and methods
This review was based on the PRISMA guidelines. An electronic search with no restrictions on language was performed from inception to August 19, 2015, in PubMed, Cochrane Central Register of Controlled Trials, EMBASE, Web of Sciences, and AMED (Ovid) databases. A manual search was also performed. Randomized clinical trials (RCTs) that compared the MBL between implants with and without microthreads in the neck were included. Qualitative synthesis and meta-analysis were performed. MBL was measured by using the mean difference (MD). Review Manager v5.3 software was used for meta-analysis (α=.05).Results
Five articles were included in the qualitative synthesis, and 3 articles were included in the meta-analysis. Four studies found that a microthread design can significantly reduce MBL under functional loading, whereas 1 study found no signi?cant difference. The homogeneity test of meta-analysis confirmed acceptable heterogeneity among the 3 studies (I2=0.49). A random-effects model was used. The result shows that MBL around implants with microthread design can be reduced signi?cantly (P=.030; MD: ?0.09; CI: ?0.18 to ?0.01).Conclusions
Meta-analysis showed that microthread design in the implant neck can reduce the amount of MBL; however, RCTs included in the review were few and the difference was small. In clinical practice, an implant with a roughened surface and microthreaded neck could be selected to maintain bone level. 相似文献17.
Marna Ribeiro Erica Hohlenwerger Fraguas Keila Ilse Cangussu Brito Yeon Jung Kim Debora Pallos Wilson Roberto Sendyk 《Journal of cranio-maxillo-facial surgery》2018,46(1):142-147
Objective
This study compared stability, removal torque, bone implant contact (BIC) and area (BA) of implants installed simultaneously with onlay autografts or allografts in rabbits' tibias.Material and methods
Total of 18 rabbits were used in this study. Fresh frozen allografts were obtained from six animals at T(-6). Two implants with autogenous grafts (Group 1) or allografts (Group 2) were simultaneously inserted into both sides of the tibiae in a vertical periimplant defect model at T0. The resonance frequency (ISQ) was measured in implant proximal epiphysis on the day of installation of T0 and T18 (18 weeks post-surgery). At T18 the removal torque was assessed at the distal implants, the implants' proximal epiphysis and surrounding bone were harvested to perform histomorphometric analysis. The BIC and BA within the limits of the implants threads were evaluated.Results
The ISQ revealed a statistically significant difference between T0 and T18 in each group (p = 0.024, p = 0.003). The removal torque indicates that there was no significant difference between the two groups (p = 0.47). No significant differences were observed between the groups regarding both BIC (p = 0.3713) and the BA (p = 0.3883).Conclusion
Both grafts and implants demonstrated the same stability, torque removal and the BIC and BA. 相似文献18.
Necati Kaleli Duygu Sarac Safak Külünk Özgür Öztürk 《The Journal of prosthetic dentistry》2018,119(3):437-445
Statement of problem
In recent years, the use of resin-matrix ceramics and polyetheretherketone (PEEK) abutments has been suggested to absorb excessive stresses on dental implants. However, only a few studies have evaluated the effect of these materials on stress distribution in implants and peripheral bone structure.Purpose
The purpose of this finite element analysis was to evaluate the biomechanical behaviors of resin-matrix ceramics and PEEK customized abutments in terms of stress distribution in implants and peripheral bone.Material and methods
Three-dimensional (3D) models of a bone-level implant system and a titanium base abutment were created by using the standard tessellation language (STL) data of original implant components. An anatomic customized abutment and a maxillary right second premolar crown were then modeled over the titanium base abutment. A bone block representing the maxillary right premolar area was created, and the implant was placed in the bone block with 100% osseointegration. Six different models were created according to combinations of restoration materials (translucent zirconia [TZI], lithium disilicate glass ceramic [IPS], polymer-infiltrated hybrid ceramic [VTE]), and customized abutment materials (PEEK and zirconia). In each model, the implants were loaded vertically (200 N) and obliquely (100 N). The stress distribution in the crown, implant, and abutments was evaluated through the von Mises stress analysis, and the stress distribution in the peripheral bone was examined through the maximum and minimum principal stress analyses.Results
The oblique load resulted in high stress values in the implant components, restorative crown, and cortical bone. Low stress values were observed in the VTE crowns. Zirconia customized abutments exhibited higher stress values than PEEK customized abutments. The stress distributions in the implant and peripheral bone were similar in all models.Conclusions
Changes in restoration and customized abutment material did not affect stress distribution in the implant and peripheral bone. 相似文献19.
Thomas F. Putters Gerry M. Raghoebar Jenneke Klein-Nulend Arjan Vissink Jurjen Schortinghuis 《Journal of cranio-maxillo-facial surgery》2019,47(1):23-28
Purpose
The aim of this study was to describe the surgical technique of immediate dental implant placement in calvarial grafts for augmentation of the severely resorbed maxilla and to assess the treatment results.Methods
In 13 patients the maxilla was augmented with calvarial bone followed by simultaneous dental implant placement (total: 68 implants). In the frontal “knife edge” region, implants were inserted in the buccal plated area. In the maxillary sinus area, implants were inserted into alveolar bone that was plated buccally or palatally through the sinus window. After 4 months, the implants were retrieved and subsequently loaded. Per-operative and post-operative variables were scored. One bone biopsy sample was taken for histological analysis.Results
The surgical procedure and wound healing was uneventful. During abutment connection after 4 months, all implants were fully osseointegrated with no signs of graft resorption. Radiographically, the mean (±SD) peri-implant bone loss after 1 year of functional loading was 0.23 ± 0.44 mm. No implants were lost. Histological examination revealed vital calvarial and maxillary bone with active remodeling.Conclusion
Immediate dental implant placement in calvarial bone grafts to rehabilitate severely resorbed maxilla is technically feasible and seems to have a high success rate. 相似文献20.
Andreas Sakkas Alexander Schramm Karsten Winter Frank Wilde 《Journal of cranio-maxillo-facial surgery》2018,46(2):312-322