In this study,different conditions of sandblasting on dental implant fixtures were investigated to achieve the best sandblasting conditions.18 different sandblasting conditions(Using 152 implant fixture samples)were e...In this study,different conditions of sandblasting on dental implant fixtures were investigated to achieve the best sandblasting conditions.18 different sandblasting conditions(Using 152 implant fixture samples)were examined,including parameters such as particle size,particle blasting pressure,and particle blasting angle.The surface treatment of the samples was performed using the SLA+Anodizing method.AFM testing was performed for each of the 18 different states,and the average surface roughness of each of these was compared with each other.Then,a bone layer was placed on the sample with the closest average surface roughness to the standard and the least amount of aluminum oxide on its surface among the 18 different states,to confirm the accuracy and quality of the desired surface roughness by examining the bone formation process and speed.The results showed that state No.4(sandblast particle size:75µm,spraying pressure of sandblast particles:4 bar,sandblast particle spraying angle:30 degrees),which was prepared using the SLA+Anodizing method and had a surface roughness of 1.989µm(The percentage of Al_(2)O_(3)on the surface=6%),had the best sandblasting conditions and showed 95%cell viability and accelerated the treatment and bone formation process for about a week.The simulation results,using Abaqus software,indicated that the stress distribution on the surface of the implant fixture in contact with the bone surface has increased by approximately 4.3%for state No.4.This will help prevent loosening of the dental implant fixture over time.展开更多
Objective: To assess the actual practical attitude and knowledge of dental implants among senior dental students and general dentists graduated from some Saudi and Non-Saudi dental schools. Methods: A total of 300 sen...Objective: To assess the actual practical attitude and knowledge of dental implants among senior dental students and general dentists graduated from some Saudi and Non-Saudi dental schools. Methods: A total of 300 senior dental students and general dentists participated in the study. Hard copies of the self-designed, multiple-choice questionnaires were distributed to all participants. The questionnaire consisted of 31 questions in five parts. Data were collected and analyzed using Chi-square test and t-test, where p Results: There is a statistically significant relationship between the participants’ answers, and their dental schools. Participants’ general knowledge, training, and teaching of dental implants, as well as information about restorations retained for the dental implants, were higher among participants from Saudi dental schools than participants from non-Saudi dental schools, while the information about dental implants was higher among participants from non-Saudi dental schools than participants from Saudi dental schools. Conclusion: We conclude that the actual practical attitude and knowledge of dental implants among participants in the current study was insufficient. Therefore, dental implant education in the undergraduate curricula of dental schools surveyed should be updated to include teaching, laboratory training, and preclinical and clinical training.展开更多
AIM: To assess the failure and bone-to-implant contact rate of dental implants placed on osteoporotic subjects. METHODS: Extensive examination strategies were created to classify studies for this systematic review. ME...AIM: To assess the failure and bone-to-implant contact rate of dental implants placed on osteoporotic subjects. METHODS: Extensive examination strategies were created to classify studies for this systematic review. MEDLINE(via Pub Med) and EMBASE database were examined for studies in English up to and including May 2014. The examination presented a combination of the MeS H words described as follow: "osteoporosis" or "osteopenia" or "estrogen deficiency" AND "implant" or "dental implant" or "osseointegration". Assessment of clinical and/or histological peri-implant conditions in osteoporosis subjects treated with titanium dental implants. The examination included a combination of the MeS H terms described as follow: "osteoporosis" or "osteopenia" or "estrogen deficiency" AND "implant" or "dental implant" or "osseointegration".RESULTS: Of 943 potentially eligible articles, 12 were included in the study. A total of 133 subjects with osteoporosis, 73 subjects diagnosed with osteopenia and 708 healthy subjects were assessed in this systematic review. In these subjects were installed 367, 205, 2981 dental implants in osteoporotic, osteopenic and healthy subjects, respectively. The failure rate of dental implant was 10.9% in osteoporotic subjects, 8.29% in osteopenic and 11.43% in healthy ones. Bone-to-implant contact obtained from retrieved implants ranged between 49.96% to 47.84%, for osteoporosis and non-osteoporotic subjects. CONCLUSION: Osteoporotic subjects presented higher rates of implant loss, however, there is a lower evidence to strengthen or refute the hypothesis that osteoporosis may have detrimental effects on bone healing. Consequently, final conclusions regarding the effect of osteoporosis in dental implant therapy cannot be made at this time. There are no randomized clinical trial accessible for evaluation and the retrospectivenature of the evaluated studies shall be taken in account when interpreting this study.展开更多
This paper aims to investigate if the dental restoration of nickel-chromium based alloy （Ni-Cr） leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had...This paper aims to investigate if the dental restoration of nickel-chromium based alloy （Ni-Cr） leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of 〈 1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of 〈1, 1 to 〈3 and 3 to 〈6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.展开更多
Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time o...Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time of dental implant. This review article describes the scientific documentation of micromotion and fretting damages on the dental implant/bone interface. The fretting amplitude is less than 30 mm in vitro and the damage in the interface is acceptable. While in vivo, the micromotion's effect is the combination of damage in tissue level and the real biological reaction.展开更多
Dental implants have spread worldwide in dentistry. The risks and complications reported are limited to local issues. However, in this case, a patient complained of systemic symptoms after dental implantation. This ca...Dental implants have spread worldwide in dentistry. The risks and complications reported are limited to local issues. However, in this case, a patient complained of systemic symptoms after dental implantation. This case report aims to demonstrate that systemic symptoms such as lumbago, shoulder stiffness, neck pain, hip joint pain, and facial pain improved after the removal of well-osseointegrated titanium implants. The results suggest that harmful electromagnetic waves received by implants affect body conditions;however, to date, the underlying mechanisms have not been identified. Therefore, further research is required.展开更多
Objective To observe the effect of high positive acceleration(+Gz) environment on dental implant osseointegration in a rabbit model and to investigate its mechanism.Methods Forty-eight New Zealand white rabbits were r...Objective To observe the effect of high positive acceleration(+Gz) environment on dental implant osseointegration in a rabbit model and to investigate its mechanism.Methods Forty-eight New Zealand white rabbits were randomly divided into 6 groups. The rabbit’s mandibular incisors were extracted and 1 implant was placed in each socket immediately. After 1 week of rest, the rabbits were exposed to a high +Gz environment, 3 times a week. The rabbits were sacrificed at 3 weeks(2 weeks +Gz exposure), 5 weeks(4 weeks +Gz exposure), and 12 weeks(4 weeks +Gz exposure and 7 weeks normal environment) after surgery, respectively. Specimens were harvested for micro-CT scanning, histological analysis, and real-time polymerase chain reaction examination.Results Compared with those in the control group, the mRNA expression levels of bone morphogenetic protein-2(BMP-2), osteopontin(OPN), and transforming growth factor-β1(TGF-β1)were significantly lower(P < 0.05), while the mRNA expression level of receptor activator of nuclear factor κB ligand(RANKL) and the RANKL/osteoprotegerin(OPG) ratio were significantly higher(P < 0.05)at 3 weeks;values of bone volume fraction, trabecular number, bone-implant contact(BIC), and TGF-β1 and OPG mRNA expression levels were significantly lower(P < 0.05), and the value of trabecular separation, RANKL mRNA expression level and RANKL/OPG ratio were significantly higher(P < 0.05) at 5 weeks;and the value of BIC was still significantly lower(P < 0.05) at 12 weeks in the experimental group.Conclusion Early exposure to the high +Gz environment after implant surgery might have an adverse effect on osseointegration, and its mechanism could be related to the inhibition of osteoblast activity and promotion of osteoclast activity.展开更多
Chronic kidney disease(CKD) is a worldwide public health problem that is growing in prevalence and is associated with severe complications. During the progression of the disease, a majority of CKD patients suffer oral...Chronic kidney disease(CKD) is a worldwide public health problem that is growing in prevalence and is associated with severe complications. During the progression of the disease, a majority of CKD patients suffer oral complications. Dental implants are currently the most reliable and successful treatment for missing teeth. However, due to complications of CKD such as infections,bone lesions, bleeding risks, and altered drug metabolism, dental implant treatment for renal failure patients on dialysis is more challenging. In this review, we have summarized the characteristics of CKD and previous publications regarding dental treatments for renal failure patients. In addition, we discuss our recent research results and clinical experience in order to provide dental implant practitioners with a clinical guideline for dental implant treatment for renal failure patients undergoing hemodialysis.展开更多
At present,dental implant surgery mainly relies on the clinical experience of the doctor and the assistance of preoperative medical imaging.However,there are some problems in dental implant surgery,such as narrow spac...At present,dental implant surgery mainly relies on the clinical experience of the doctor and the assistance of preoperative medical imaging.However,there are some problems in dental implant surgery,such as narrow space,sight obstruction,inaccurate positioning,and high requirements of doctors’proficiency.Therefore,a dental implant robot system(DIRS)guided by optical navigation is developed in this study,with an x-shaped tool and an irregular pentagonal tracer are designed for spatial registration and needle tip positioning strategy respectively.The coordinate system of each unit in DIRS is unified through system calibration,spatial registration,and needle tip positioning strategy.Then the surgical path is planned on the computed tomography(CT)images in the navigation software before operation.The automatic positioning method and the auxiliary positioning method can be used in the operation to achieve accurate positioning and assist doctors to complete the operation.The errors of spatial registration,needle tip positioning strategy,and the overall accuracy of the system were evaluated respectively,and the results showed that they all met the needs of clinical surgery.This study preliminarily verified the feasibility of the precise positioning method for dental surgery robots and provided certain ideas for subsequent related research.展开更多
The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. San...The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. Sand-blasted titanium alloy dental implants were anodized in dilute hydrofluoric acid (HF(aq)) solution using a Sorensen DLM 300-2 power supply. The HF concentration and anodization time were varied and the resulting implant surfaces were evaluated using a Jeol JSM-5310LV Scanning Electron Microscope to determine the ideal anodization conditions. While HF is necessary to facilitate oxide growth, increasing concentrations resulted in proportionate increases in coating delamination. In a similar manner, a minimum anodization time of 1 hour was necessary for oxide growth but longer times produced more delamination especially at higher HF(aq) concentrations. SEM imaging showed that implants anodized for 1 hour in a 0.1% HF(aq) aqueous solution had the best results. Anodization can be used to generate niobium oxide coatings on sand-blasted Ti alloy dental implants by balancing the competing factors of oxide growth and coating delamination. It is believed that these oxide coatings have the potential to improve osseointegration relative to untreated dental implants when evaluated in an in vivo study.展开更多
To evaluate the papilla alterations around single-implant restorations in the anterior maxillae after crown attachment and to study the influence of soft tissue thickness on the papilla fill alteration.According to th...To evaluate the papilla alterations around single-implant restorations in the anterior maxillae after crown attachment and to study the influence of soft tissue thickness on the papilla fill alteration.According to the inclusion criteria,32 patients subjected to implant-supported single-tooth restorations in anterior maxillae were included.The patients were assigned to two groups according to the mucosal thickness:(i) group 1,1.5mm≤fmucosal thicknessf≤3mm;and (ii) group 2,3 mm≤mucosal thickness≤4.5 mm.Assessments of interproximal papillae at the time of crown placement (baseline) and at 6-month postloading (follow-up) were made by two prosthodontists using papilla fill index (PFI).The mean mucosal thickness was (2.49±0.31) mm (group 1) and (3.81±0.31) mm (group 2) for the two groups respectively.A significant difference in PFI between the groups was detected at the baseline (P<0.001).PFI improvements over time occurred after 6-month follow-up irrespective of the groups.When compared to group 1,the likelihood to obtain papilla fill was significantly higher for group 2 with an odds ratio of 6.05 (P<0.001).The interproximal papilla level around single-implant restorations could improve significantly over time after 6-month restoration according to PFI assessment.The thicker mucosa before implant placement implied a more favorable esthetic outcome in papilla alteration.展开更多
AIM: To discuss important characteristics of the useof dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE(PubM ed) from 1...AIM: To discuss important characteristics of the useof dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE(PubM ed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review. RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations(bone quantity and density), radiographic techniques, implant selection(number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters. CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning.展开更多
Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant mat...Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2 OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium(Ti), titanium-zirconium(Ti Zr) alloys and zirconia surfaces. Monoculture studies with either U2 OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2 OS osteoblasts were favourable on all materials. Adhering U2 OS osteoblasts cells, however,were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from Ti Zr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.展开更多
Objective:To assess the biomechanical properties of a new design configuration for zirconia dental implants. Methods: The new design has a cylindrical shape that is partially hollow and porous in the bottom, which per...Objective:To assess the biomechanical properties of a new design configuration for zirconia dental implants. Methods: The new design has a cylindrical shape that is partially hollow and porous in the bottom, which permits the implants to be locked into the alveolar bone over time. It also utilizes bioactive glass coatings to increase adhesion to surrounding bone structure. Samples of the new design were fabricated in the laboratory and their material strength, hardness, and fracture toughness were evaluated. In addition, biocompatibility of the new design was evaluated through testing in dogs. Results: Results of mechanical tests indicate that structural properties of the new design exceed the usual requirements for implants. Moreover, animal tests suggest that there is appreciable improvement in lock-in strength and osteointegration. Conclusion: The new design configuration is biomechanically feasible and further research is warranted to improve the design for human use.展开更多
The development of the activated cellular bony implant, in light of the principle on tissue engineering, has brought about a new era to the fields of dental maxillofacial implantation. The present study separated the ...The development of the activated cellular bony implant, in light of the principle on tissue engineering, has brought about a new era to the fields of dental maxillofacial implantation. The present study separated the osteoblast like cells from human alveolar bone and seeded them into 3 types of biodegradable scaffold to form the complexes and then evaluated their osteogenic activities in vitro, in order to acquire experimental data that are essential to future clinical practice of this new type of therapeutical procedure in oral and maxillofacial surgery. Material and methods: Human alveolar bone origin cells were separated from alveolar bone around the third impacted teeth of 3 patients by enzyme digestion and went on cultures with α MEM containing β glycerophosphate and Dexamethasone at 5% CO2 ,37℃ for 21 28 days. Confirmed osteoblasts like cells were then seeded onto 3 types of degradable biomaterials of polyglycolic acid scaffold, collagen sponge, and L lactic acid/ε caprolactone to form cell matrices complexes. The 3 types of complex were continued to culture for 21 28 days in vitro at the same conditions with the single layer cultured cells. The cell proliferation, morphological changes, ALPase activity and mineral nodules formation on scaffolds were measured and observed at 3 days intervals to evaluate the affinities & the osteogenic activities of the human alveolar osteoblast like cells in the 3 different complexes. Result and discussion: The results indicated that the cultured human alveolar bone origin cells from 3 patients could successfully express the osteoblasts phenotype in single layered culturing in vitro after stimulated by β glycerophosphate and Dexamethasone. It has been shown that the cultured osteoblast like cells seeded on PGAS matrix had the highest attachmental, proliferative and osteogenic activities, suggesting a good bio affinity between the human alveolar osteoblast like cells and the PGAS matrix. The statistical analysis (ANOVA) showed that there were significant differences between PGAS osteoblasts complex and CLGS or LACT complexes on osteogenic activities. (P<0.05). It was also noticed that cultured human alveolar osteoblasts seeded in biodegradable materials had a delayed peak period on cell proliferation and PLAase production ,suggesting the osteoblasts seeded on scaffolds need a period of time to adjust themselves before they can normally proliferate and expres their phenotypes. Conclusion: PGAS osteoblasts complex is worth to be further developed into a tissue engineered cellular artificial bony implant for reconstructing the oral maxillofacial bony defects in a more effective way in the future.展开更多
This case report describes an extraordinary case of the spontaneous transmaxillary-transnasal discharge of a dental implant, which occurred during a sneeze. The patient was complained of symptoms of acute sinusitis. S...This case report describes an extraordinary case of the spontaneous transmaxillary-transnasal discharge of a dental implant, which occurred during a sneeze. The patient was complained of symptoms of acute sinusitis. She underwent a computed tomography scan that revealed a dental implant dislocated in the maxillary sinus. Medical treatment based on antibiotics and mucolytics was administered to the patient in order to prepare her for endoscopic endonasal surgery. The implant was spontaneously discharged two days after during a sneeze. Mucociliary clearance in combination with a local osteolytic inflammatory process and mucolytics therapy are the likely causes of this unusual discharge.展开更多
Overdenture as a treatment modality for both partially and fully edentulous patients is costeffective and less expensive. The purpose of the present study was to examine the newly fabricated attachments by comparing t...Overdenture as a treatment modality for both partially and fully edentulous patients is costeffective and less expensive. The purpose of the present study was to examine the newly fabricated attachments by comparing them with conventional O-ring attachment in vitro in terms of retention force and cyclic aging resistance. A total of 150 samples were prepared and divided into five groups according to the materials used(O-ring attachment, Deflex M10 XR, Deflex Classic SR, Deflex Acrilato FD, and flexible acrylic resin). The retention force of different attachments was measured by a mini dental implant after three subsequent aging(0, 63, and 126) cycles in the circumstances similar to the oral environment. The gap space between the head of the implant and the inner surface of the attachments was detected. Two-way analysis of variance(ANOVA) analysis with multiple comparisons test was applied for statistical analysis. The results showed that Deflex M10 XR had the highest retention force and the lowest gap space after cyclic aging; in addition, by comparing the relative force reduction, the lowest values were obtained in the O-ring attachment and the highest values in the flexible acrylic resin attachment. The retention force measured after cyclic aging for the Deflex M10 XR attachment was greatly improved when compared with the O-ring attachment and other types of attachment materials; in addition, the Deflex M10 XR attachment exhibited the minimum gap space between the inner surface and the mini dental implant head. In conclusion, Deflex M10 XR has the ability to withstand weathering conditions and retains its durable and retentive properties after aging when compared with other attachments.展开更多
The surface treatment is important for titanium and its alloys as promising candidates for dental implantation due to their bioinert surface.Titanium surface samples were modified using H2O2 solution at different time...The surface treatment is important for titanium and its alloys as promising candidates for dental implantation due to their bioinert surface.Titanium surface samples were modified using H2O2 solution at different times up to 72 h to boost their bioactivity.According to the results of the field emission scanning electron microscopy test,some nanostructures are formed on the surface of treated titanium samples and increased in size by increasing the time of treatment up to 24 h.After 24 h of application,the sharpness of nanostructures decreased and the micro-cracks and discontinuity in the coating surface increased.The results of the X-ray diffraction study and Raman spectroscopy revealed that anatase(TiO2)was formed on the surface of treated titanium samples.The peak intensity of Raman spectroscopy increased with an improvement in treatment time of up to 24 h and then decreased due to the discontinuity of the coating.Full wettability and ability to form apatite were reached at 6 h of treatment.It is clear that the treatment time has a significant effect on the surface treatment of titanium using the H2O2 solution.展开更多
[Objectives] To explore the flexural strength of 3D printed titanium bone bionic dental implants and provide a scientific basis for the clinical application of 3D printed porous bionic bone dental implants. [Methods] ...[Objectives] To explore the flexural strength of 3D printed titanium bone bionic dental implants and provide a scientific basis for the clinical application of 3D printed porous bionic bone dental implants. [Methods] The cone-beam CT( CBCT) image information of 20 premolars extracted by orthodontic requirement was collected,and a new porous bone bionic dental implant was produced using modeling software and 3D printer. The premolars were divided into two groups( A and B). The universal testing machine was used to test the flexural strength of the two groups and the difference in flexural strength between the two groups was compared through statistics. [Results]Twenty 3D printed porous titanium bone bionic implants were accurately produced; the morphology of group A and group B were extremely similar to each other; the average flexural strength of group A was 2 767. 92 N,while the average flexural strength of group B was 778. 77 N,showing that the average flexural strength of group A was significantly higher than that of group B,and the difference was statistically significant( P < 0. 05).[Conclusions]The personalized porous structure root implants produced by 3D printing technology are very similar to the target tooth morphology,and show high accuracy and small error of production. Besides,the flexural strength of 3D printed personalized porous structure root implants can fully meet the requirements of the maximum occlusal force for dental implant restoration. It is expected to provide a scientific basis for clinical application of 3 D printed porous bionic bone tooth implants.展开更多
The insertion torque of a dental implant is an important indicator for the primary stability of dental implants.Thus,the preoperative prediction for the insertion torque is crucial to improve the success rate of impla...The insertion torque of a dental implant is an important indicator for the primary stability of dental implants.Thus,the preoperative prediction for the insertion torque is crucial to improve the success rate of implantation surgery.In this present research,an alternative method for prediction of implant torque was proposed.First,the mechanical model for the insertion torque was established based on an oblique cutting process.In the proposed mechanical model,three factors,including bone quality,implant geometry and surgical methods were considered in terms of bone-quality coefficients,chip load and insertion speeds,respectively.Then,the defined bone-quality coefficients for cancellous bone with the computed tomography(CT)value of 235–245,345–355 and 415–425 Hu were obtained by a series of insertion experiments of IS and ITI implants.Finally,the insertion experiments of DIO implants were carried out to verify the accuracy of developed model.The predicted insertion torques calculated by the mechanical model were compared with those acquired by insertion experiments,with good agreement,the relative error being less than 15%.This method allows the insertion torque for different implant types to be quickly established and enhances prediction accuracy by considering the effects of implants’geometries and surgical methods.展开更多
文摘In this study,different conditions of sandblasting on dental implant fixtures were investigated to achieve the best sandblasting conditions.18 different sandblasting conditions(Using 152 implant fixture samples)were examined,including parameters such as particle size,particle blasting pressure,and particle blasting angle.The surface treatment of the samples was performed using the SLA+Anodizing method.AFM testing was performed for each of the 18 different states,and the average surface roughness of each of these was compared with each other.Then,a bone layer was placed on the sample with the closest average surface roughness to the standard and the least amount of aluminum oxide on its surface among the 18 different states,to confirm the accuracy and quality of the desired surface roughness by examining the bone formation process and speed.The results showed that state No.4(sandblast particle size:75µm,spraying pressure of sandblast particles:4 bar,sandblast particle spraying angle:30 degrees),which was prepared using the SLA+Anodizing method and had a surface roughness of 1.989µm(The percentage of Al_(2)O_(3)on the surface=6%),had the best sandblasting conditions and showed 95%cell viability and accelerated the treatment and bone formation process for about a week.The simulation results,using Abaqus software,indicated that the stress distribution on the surface of the implant fixture in contact with the bone surface has increased by approximately 4.3%for state No.4.This will help prevent loosening of the dental implant fixture over time.
文摘Objective: To assess the actual practical attitude and knowledge of dental implants among senior dental students and general dentists graduated from some Saudi and Non-Saudi dental schools. Methods: A total of 300 senior dental students and general dentists participated in the study. Hard copies of the self-designed, multiple-choice questionnaires were distributed to all participants. The questionnaire consisted of 31 questions in five parts. Data were collected and analyzed using Chi-square test and t-test, where p Results: There is a statistically significant relationship between the participants’ answers, and their dental schools. Participants’ general knowledge, training, and teaching of dental implants, as well as information about restorations retained for the dental implants, were higher among participants from Saudi dental schools than participants from non-Saudi dental schools, while the information about dental implants was higher among participants from non-Saudi dental schools than participants from Saudi dental schools. Conclusion: We conclude that the actual practical attitude and knowledge of dental implants among participants in the current study was insufficient. Therefore, dental implant education in the undergraduate curricula of dental schools surveyed should be updated to include teaching, laboratory training, and preclinical and clinical training.
基金Supported by Sao Paulo Research Foundation,FAPESP,No.2008/06972-6The National Council for Scientific and Technological Development,CNPq Nos.579157/2008-3,302768/2009-2 and 473282/2007-0+1 种基金Pesq-Doc scholarship to Dr.Shibli from University of GuaruhosScholarship to Dr.Giro from University of Guarulhos
文摘AIM: To assess the failure and bone-to-implant contact rate of dental implants placed on osteoporotic subjects. METHODS: Extensive examination strategies were created to classify studies for this systematic review. MEDLINE(via Pub Med) and EMBASE database were examined for studies in English up to and including May 2014. The examination presented a combination of the MeS H words described as follow: "osteoporosis" or "osteopenia" or "estrogen deficiency" AND "implant" or "dental implant" or "osseointegration". Assessment of clinical and/or histological peri-implant conditions in osteoporosis subjects treated with titanium dental implants. The examination included a combination of the MeS H terms described as follow: "osteoporosis" or "osteopenia" or "estrogen deficiency" AND "implant" or "dental implant" or "osseointegration".RESULTS: Of 943 potentially eligible articles, 12 were included in the study. A total of 133 subjects with osteoporosis, 73 subjects diagnosed with osteopenia and 708 healthy subjects were assessed in this systematic review. In these subjects were installed 367, 205, 2981 dental implants in osteoporotic, osteopenic and healthy subjects, respectively. The failure rate of dental implant was 10.9% in osteoporotic subjects, 8.29% in osteopenic and 11.43% in healthy ones. Bone-to-implant contact obtained from retrieved implants ranged between 49.96% to 47.84%, for osteoporosis and non-osteoporotic subjects. CONCLUSION: Osteoporotic subjects presented higher rates of implant loss, however, there is a lower evidence to strengthen or refute the hypothesis that osteoporosis may have detrimental effects on bone healing. Consequently, final conclusions regarding the effect of osteoporosis in dental implant therapy cannot be made at this time. There are no randomized clinical trial accessible for evaluation and the retrospectivenature of the evaluated studies shall be taken in account when interpreting this study.
基金supported by Open Fund of State Key Laboratory of Oral Diseases,Sichun University
文摘This paper aims to investigate if the dental restoration of nickel-chromium based alloy （Ni-Cr） leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of 〈 1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of 〈1, 1 to 〈3 and 3 to 〈6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.
基金the support of the National Natural Science Foundation of China (Nos. 81170996, 81070867, and 81100777)Sichuan Province Science and Technology Innovation Team Program (2011JTD0006)
文摘Micromotion and fretting damages at the dental implant/bone interface are neglected for the limitation of check methods, but it is particularly important for the initial success of osseointegration and the life time of dental implant. This review article describes the scientific documentation of micromotion and fretting damages on the dental implant/bone interface. The fretting amplitude is less than 30 mm in vitro and the damage in the interface is acceptable. While in vivo, the micromotion's effect is the combination of damage in tissue level and the real biological reaction.
文摘Dental implants have spread worldwide in dentistry. The risks and complications reported are limited to local issues. However, in this case, a patient complained of systemic symptoms after dental implantation. This case report aims to demonstrate that systemic symptoms such as lumbago, shoulder stiffness, neck pain, hip joint pain, and facial pain improved after the removal of well-osseointegrated titanium implants. The results suggest that harmful electromagnetic waves received by implants affect body conditions;however, to date, the underlying mechanisms have not been identified. Therefore, further research is required.
基金financially supported by China Postdoctoral Science Foundation [No.2016M592971]Logistics Department of the Chinese People’s Liberation Army [No.AKJ15J003]
文摘Objective To observe the effect of high positive acceleration(+Gz) environment on dental implant osseointegration in a rabbit model and to investigate its mechanism.Methods Forty-eight New Zealand white rabbits were randomly divided into 6 groups. The rabbit’s mandibular incisors were extracted and 1 implant was placed in each socket immediately. After 1 week of rest, the rabbits were exposed to a high +Gz environment, 3 times a week. The rabbits were sacrificed at 3 weeks(2 weeks +Gz exposure), 5 weeks(4 weeks +Gz exposure), and 12 weeks(4 weeks +Gz exposure and 7 weeks normal environment) after surgery, respectively. Specimens were harvested for micro-CT scanning, histological analysis, and real-time polymerase chain reaction examination.Results Compared with those in the control group, the mRNA expression levels of bone morphogenetic protein-2(BMP-2), osteopontin(OPN), and transforming growth factor-β1(TGF-β1)were significantly lower(P < 0.05), while the mRNA expression level of receptor activator of nuclear factor κB ligand(RANKL) and the RANKL/osteoprotegerin(OPG) ratio were significantly higher(P < 0.05)at 3 weeks;values of bone volume fraction, trabecular number, bone-implant contact(BIC), and TGF-β1 and OPG mRNA expression levels were significantly lower(P < 0.05), and the value of trabecular separation, RANKL mRNA expression level and RANKL/OPG ratio were significantly higher(P < 0.05) at 5 weeks;and the value of BIC was still significantly lower(P < 0.05) at 12 weeks in the experimental group.Conclusion Early exposure to the high +Gz environment after implant surgery might have an adverse effect on osseointegration, and its mechanism could be related to the inhibition of osteoblast activity and promotion of osteoclast activity.
基金supported by grants from the National Natural Science Foundation of China(NSFC 81371173)the State Key Laboratory of Oral Diseases(SKLOD201704)+1 种基金the International Team for Implantology(Grant No.975_2014,Basel,Switzerland)the National Key R&D Program of China during the thirteenth Five-Year Plan(2016YFC1102700)
文摘Chronic kidney disease(CKD) is a worldwide public health problem that is growing in prevalence and is associated with severe complications. During the progression of the disease, a majority of CKD patients suffer oral complications. Dental implants are currently the most reliable and successful treatment for missing teeth. However, due to complications of CKD such as infections,bone lesions, bleeding risks, and altered drug metabolism, dental implant treatment for renal failure patients on dialysis is more challenging. In this review, we have summarized the characteristics of CKD and previous publications regarding dental treatments for renal failure patients. In addition, we discuss our recent research results and clinical experience in order to provide dental implant practitioners with a clinical guideline for dental implant treatment for renal failure patients undergoing hemodialysis.
基金Natural Science Foundation of Guangdong Province(Grant No.2021A1515011208)National Natural Scientific Foundation of China(Grant No.81671788)+1 种基金National Science Foundation for Young Scientists of China(Grant No.81701662)The Joint Found of National Science Foundation of China and GuangDong Provincial Government(Grant No.U1301258).
文摘At present,dental implant surgery mainly relies on the clinical experience of the doctor and the assistance of preoperative medical imaging.However,there are some problems in dental implant surgery,such as narrow space,sight obstruction,inaccurate positioning,and high requirements of doctors’proficiency.Therefore,a dental implant robot system(DIRS)guided by optical navigation is developed in this study,with an x-shaped tool and an irregular pentagonal tracer are designed for spatial registration and needle tip positioning strategy respectively.The coordinate system of each unit in DIRS is unified through system calibration,spatial registration,and needle tip positioning strategy.Then the surgical path is planned on the computed tomography(CT)images in the navigation software before operation.The automatic positioning method and the auxiliary positioning method can be used in the operation to achieve accurate positioning and assist doctors to complete the operation.The errors of spatial registration,needle tip positioning strategy,and the overall accuracy of the system were evaluated respectively,and the results showed that they all met the needs of clinical surgery.This study preliminarily verified the feasibility of the precise positioning method for dental surgery robots and provided certain ideas for subsequent related research.
文摘The purpose of this study was to use scanning electron microscopy (SEM) evaluation to determine the optimal anodizetion conditions needed to generate niobium oxide coatings on titanium alloy dental implant screws. Sand-blasted titanium alloy dental implants were anodized in dilute hydrofluoric acid (HF(aq)) solution using a Sorensen DLM 300-2 power supply. The HF concentration and anodization time were varied and the resulting implant surfaces were evaluated using a Jeol JSM-5310LV Scanning Electron Microscope to determine the ideal anodization conditions. While HF is necessary to facilitate oxide growth, increasing concentrations resulted in proportionate increases in coating delamination. In a similar manner, a minimum anodization time of 1 hour was necessary for oxide growth but longer times produced more delamination especially at higher HF(aq) concentrations. SEM imaging showed that implants anodized for 1 hour in a 0.1% HF(aq) aqueous solution had the best results. Anodization can be used to generate niobium oxide coatings on sand-blasted Ti alloy dental implants by balancing the competing factors of oxide growth and coating delamination. It is believed that these oxide coatings have the potential to improve osseointegration relative to untreated dental implants when evaluated in an in vivo study.
基金supported by Science and Technology Commission of Shanghai Municipality (09411955000 and 1052nm04500)National Natural Science Foundation of China (31070842)National Basic Research Program of China (2012CB933604)
文摘To evaluate the papilla alterations around single-implant restorations in the anterior maxillae after crown attachment and to study the influence of soft tissue thickness on the papilla fill alteration.According to the inclusion criteria,32 patients subjected to implant-supported single-tooth restorations in anterior maxillae were included.The patients were assigned to two groups according to the mucosal thickness:(i) group 1,1.5mm≤fmucosal thicknessf≤3mm;and (ii) group 2,3 mm≤mucosal thickness≤4.5 mm.Assessments of interproximal papillae at the time of crown placement (baseline) and at 6-month postloading (follow-up) were made by two prosthodontists using papilla fill index (PFI).The mean mucosal thickness was (2.49±0.31) mm (group 1) and (3.81±0.31) mm (group 2) for the two groups respectively.A significant difference in PFI between the groups was detected at the baseline (P<0.001).PFI improvements over time occurred after 6-month follow-up irrespective of the groups.When compared to group 1,the likelihood to obtain papilla fill was significantly higher for group 2 with an odds ratio of 6.05 (P<0.001).The interproximal papilla level around single-implant restorations could improve significantly over time after 6-month restoration according to PFI assessment.The thicker mucosa before implant placement implied a more favorable esthetic outcome in papilla alteration.
文摘AIM: To discuss important characteristics of the useof dental implants in posterior quadrants and the rehabilitation planning. METHODS: An electronic search of English articles was conducted on MEDLINE(PubM ed) from 1990 up to the period of March 2014. The key terms were dental implants and posterior jaws, dental implants/treatment planning and posterior maxilla, and dental implants/treatment planning and posterior mandible. No exclusion criteria were used for the initial search. Clinical trials, randomized and non randomized studies, classical and comparative studies, multicenter studies, in vitro and in vivo studies, case reports, longitudinal studies and reviews of the literature were included in this review. RESULTS: One hundred and fifty-two articles met the inclusion criteria of treatment planning of dental implants in posterior jaw and were read in their entirety. The selected articles were categorized with respect to their context on space for restoration, anatomic considerations(bone quantity and density), radiographic techniques, implant selection(number, position, diameter and surface), tilted and pterygoid implants, short implants, occlusal considerations, and success rates of implants placed in the posterior region. The results derived from the review process were described under several different topic headings to give readers a clear overview of the literature. In general, it was observed that the use of dental implants in posterior region requires a careful treatment plan. It is important that the practitioner has knowledge about the theme to evaluate the treatment parameters. CONCLUSION: The use of implants to restore the posterior arch presents many challenges and requires a detailed treatment planning.
文摘Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2 OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium(Ti), titanium-zirconium(Ti Zr) alloys and zirconia surfaces. Monoculture studies with either U2 OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2 OS osteoblasts were favourable on all materials. Adhering U2 OS osteoblasts cells, however,were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from Ti Zr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.
文摘Objective:To assess the biomechanical properties of a new design configuration for zirconia dental implants. Methods: The new design has a cylindrical shape that is partially hollow and porous in the bottom, which permits the implants to be locked into the alveolar bone over time. It also utilizes bioactive glass coatings to increase adhesion to surrounding bone structure. Samples of the new design were fabricated in the laboratory and their material strength, hardness, and fracture toughness were evaluated. In addition, biocompatibility of the new design was evaluated through testing in dogs. Results: Results of mechanical tests indicate that structural properties of the new design exceed the usual requirements for implants. Moreover, animal tests suggest that there is appreciable improvement in lock-in strength and osteointegration. Conclusion: The new design configuration is biomechanically feasible and further research is warranted to improve the design for human use.
文摘The development of the activated cellular bony implant, in light of the principle on tissue engineering, has brought about a new era to the fields of dental maxillofacial implantation. The present study separated the osteoblast like cells from human alveolar bone and seeded them into 3 types of biodegradable scaffold to form the complexes and then evaluated their osteogenic activities in vitro, in order to acquire experimental data that are essential to future clinical practice of this new type of therapeutical procedure in oral and maxillofacial surgery. Material and methods: Human alveolar bone origin cells were separated from alveolar bone around the third impacted teeth of 3 patients by enzyme digestion and went on cultures with α MEM containing β glycerophosphate and Dexamethasone at 5% CO2 ,37℃ for 21 28 days. Confirmed osteoblasts like cells were then seeded onto 3 types of degradable biomaterials of polyglycolic acid scaffold, collagen sponge, and L lactic acid/ε caprolactone to form cell matrices complexes. The 3 types of complex were continued to culture for 21 28 days in vitro at the same conditions with the single layer cultured cells. The cell proliferation, morphological changes, ALPase activity and mineral nodules formation on scaffolds were measured and observed at 3 days intervals to evaluate the affinities & the osteogenic activities of the human alveolar osteoblast like cells in the 3 different complexes. Result and discussion: The results indicated that the cultured human alveolar bone origin cells from 3 patients could successfully express the osteoblasts phenotype in single layered culturing in vitro after stimulated by β glycerophosphate and Dexamethasone. It has been shown that the cultured osteoblast like cells seeded on PGAS matrix had the highest attachmental, proliferative and osteogenic activities, suggesting a good bio affinity between the human alveolar osteoblast like cells and the PGAS matrix. The statistical analysis (ANOVA) showed that there were significant differences between PGAS osteoblasts complex and CLGS or LACT complexes on osteogenic activities. (P<0.05). It was also noticed that cultured human alveolar osteoblasts seeded in biodegradable materials had a delayed peak period on cell proliferation and PLAase production ,suggesting the osteoblasts seeded on scaffolds need a period of time to adjust themselves before they can normally proliferate and expres their phenotypes. Conclusion: PGAS osteoblasts complex is worth to be further developed into a tissue engineered cellular artificial bony implant for reconstructing the oral maxillofacial bony defects in a more effective way in the future.
文摘This case report describes an extraordinary case of the spontaneous transmaxillary-transnasal discharge of a dental implant, which occurred during a sneeze. The patient was complained of symptoms of acute sinusitis. She underwent a computed tomography scan that revealed a dental implant dislocated in the maxillary sinus. Medical treatment based on antibiotics and mucolytics was administered to the patient in order to prepare her for endoscopic endonasal surgery. The implant was spontaneously discharged two days after during a sneeze. Mucociliary clearance in combination with a local osteolytic inflammatory process and mucolytics therapy are the likely causes of this unusual discharge.
文摘Overdenture as a treatment modality for both partially and fully edentulous patients is costeffective and less expensive. The purpose of the present study was to examine the newly fabricated attachments by comparing them with conventional O-ring attachment in vitro in terms of retention force and cyclic aging resistance. A total of 150 samples were prepared and divided into five groups according to the materials used(O-ring attachment, Deflex M10 XR, Deflex Classic SR, Deflex Acrilato FD, and flexible acrylic resin). The retention force of different attachments was measured by a mini dental implant after three subsequent aging(0, 63, and 126) cycles in the circumstances similar to the oral environment. The gap space between the head of the implant and the inner surface of the attachments was detected. Two-way analysis of variance(ANOVA) analysis with multiple comparisons test was applied for statistical analysis. The results showed that Deflex M10 XR had the highest retention force and the lowest gap space after cyclic aging; in addition, by comparing the relative force reduction, the lowest values were obtained in the O-ring attachment and the highest values in the flexible acrylic resin attachment. The retention force measured after cyclic aging for the Deflex M10 XR attachment was greatly improved when compared with the O-ring attachment and other types of attachment materials; in addition, the Deflex M10 XR attachment exhibited the minimum gap space between the inner surface and the mini dental implant head. In conclusion, Deflex M10 XR has the ability to withstand weathering conditions and retains its durable and retentive properties after aging when compared with other attachments.
基金This work was financially supported by Grant-in-Aid(Nos.19K10250 and 18K09686)from Scientific Research of the Japan Society for the Promotion of Science(JSPS).
文摘The surface treatment is important for titanium and its alloys as promising candidates for dental implantation due to their bioinert surface.Titanium surface samples were modified using H2O2 solution at different times up to 72 h to boost their bioactivity.According to the results of the field emission scanning electron microscopy test,some nanostructures are formed on the surface of treated titanium samples and increased in size by increasing the time of treatment up to 24 h.After 24 h of application,the sharpness of nanostructures decreased and the micro-cracks and discontinuity in the coating surface increased.The results of the X-ray diffraction study and Raman spectroscopy revealed that anatase(TiO2)was formed on the surface of treated titanium samples.The peak intensity of Raman spectroscopy increased with an improvement in treatment time of up to 24 h and then decreased due to the discontinuity of the coating.Full wettability and ability to form apatite were reached at 6 h of treatment.It is clear that the treatment time has a significant effect on the surface treatment of titanium using the H2O2 solution.
文摘[Objectives] To explore the flexural strength of 3D printed titanium bone bionic dental implants and provide a scientific basis for the clinical application of 3D printed porous bionic bone dental implants. [Methods] The cone-beam CT( CBCT) image information of 20 premolars extracted by orthodontic requirement was collected,and a new porous bone bionic dental implant was produced using modeling software and 3D printer. The premolars were divided into two groups( A and B). The universal testing machine was used to test the flexural strength of the two groups and the difference in flexural strength between the two groups was compared through statistics. [Results]Twenty 3D printed porous titanium bone bionic implants were accurately produced; the morphology of group A and group B were extremely similar to each other; the average flexural strength of group A was 2 767. 92 N,while the average flexural strength of group B was 778. 77 N,showing that the average flexural strength of group A was significantly higher than that of group B,and the difference was statistically significant( P < 0. 05).[Conclusions]The personalized porous structure root implants produced by 3D printing technology are very similar to the target tooth morphology,and show high accuracy and small error of production. Besides,the flexural strength of 3D printed personalized porous structure root implants can fully meet the requirements of the maximum occlusal force for dental implant restoration. It is expected to provide a scientific basis for clinical application of 3 D printed porous bionic bone tooth implants.
基金Major Research&Development Program of Shandong Province(Grant No.2015GGX103043)Taishan Scholars Program of Shandong Province(Grant No.ts201712002).
文摘The insertion torque of a dental implant is an important indicator for the primary stability of dental implants.Thus,the preoperative prediction for the insertion torque is crucial to improve the success rate of implantation surgery.In this present research,an alternative method for prediction of implant torque was proposed.First,the mechanical model for the insertion torque was established based on an oblique cutting process.In the proposed mechanical model,three factors,including bone quality,implant geometry and surgical methods were considered in terms of bone-quality coefficients,chip load and insertion speeds,respectively.Then,the defined bone-quality coefficients for cancellous bone with the computed tomography(CT)value of 235–245,345–355 and 415–425 Hu were obtained by a series of insertion experiments of IS and ITI implants.Finally,the insertion experiments of DIO implants were carried out to verify the accuracy of developed model.The predicted insertion torques calculated by the mechanical model were compared with those acquired by insertion experiments,with good agreement,the relative error being less than 15%.This method allows the insertion torque for different implant types to be quickly established and enhances prediction accuracy by considering the effects of implants’geometries and surgical methods.
