Review of PEEK implants and biomechanical and immunological responses to a zirconium phosphate nano-coated PEEK, a blasted PEEK, and a turned titanium implant surface.

PURPOSE: To investigate the biomechanical and immunological reactions to coated and non-coated blasted PEEK implants in vivo after 12 weeks and review the associated literature. METHODS: Two osteotomy sites were performed in each proximal tibia of 10 lop-eared rabbits (n= 4 per rabbit). Each rabbit received a randomly placed (1) blasted zirconium phosphate nano-coated PEEK- (nano-ZrP), (2) blasted PEEK- (PEEK) and (3) titanium implant (Ti) and an empty sham site. At 12 weeks, removal torque of all implants and biological investigation with qPCR was performed. The implant surfaces were analyzed prior to insertion with interferometry, SEM and XPS. RESULTS: The interferometry analysis showed that there was no difference in roughness for the uncoated PEEK compared to the ZrP coated PEEK implants. The titanium implants were considerably smoother (Sa= 0.23 µm) than the uncoated Sa= 1.11 µm) and ZrP coated PEEK implants (Sa= 1.12 µm). SEM analysis on the PEEK implants corroborated the interferometry results; no difference in structure between the uncoated vs. the ZrP coated PEEK was visible on the micrometer level. At higher magnifications, the ZrP coating was visible in the SEM as a thin, porous network. All tested implants displayed osseointegration with the highest RTQ for nano-ZrP (18.4 Ncm) followed by PEEK (14.5 Ncm) and Ti (11.5 Ncm). All implants activated the immune system, with elevated macrophage and M2 macrophage qPCR markers at 12 weeks compared to the sham site. CLINICAL SIGNIFICANCE: Nano-ZrP coating improves osseointegration of blasted PEEK implants at 12 weeks of follow-up. Osseointegration of titanium, PEEK and nano-ZrP PEEK is not a normal bone healing process, but rather a shield-off mechanism that appears to be regulated by the innate immune system.

Initial and long-term crestal bone responses to modern dental implants.

Successful osseointegration is the result of a controlled foreign body reaction to dental implants. Osseointegrated implants have demonstrated excellent long-term survivability, although they may be subject to limited marginal bone loss. Marginal bone loss during the first few years after implant placement seldom represents disease, but is instead the result of an adaptive bone response to surgical trauma and implant loading. It is not uncommon for implants with early marginal bone loss to enter a long-lasting state of bone stability. Extensive bone resorption after the first year is generally due to an exacerbation of adverse body reactions caused by non-optimal implant components, adverse surgery or prosthodontics and/or compromised patient factors. Disease in the form of peri-implantitis is a late complication that affects some implants with suppuration and rapid loss of crestal bone, and is probably caused by bacterial pathogens and immunological reactions. Unfortunately, the literature is not consistent with respect to the type or magnitude of clinical implant problems, including how they are defined and diagnosed. If the peri-implantitis diagnosis is confined to cases with infection, suppuration and significant bone loss, the frequency of the disease is relatively low, which is in sharp contrast to the frequencies reported with unrealistic definitions of peri-implantitis. We suggest that when modern implants are placed by properly trained individuals, only 1-2% of implants show true peri-implantitis during follow-up periods of 10 years or more. Peri-implantitis must be separated from the initial and self-limiting marginal bone loss.

Survival of dental implants placed in sites of previously failed implants.

OBJECTIVES: To assess the survival of dental implants placed in sites of previously failed implants and to explore the possible factors that might affect the outcome of this reimplantation procedure. MATERIALS AND METHODS: Patients that had failed dental implants, which were replaced with the same implant type at the same site, were included. Descriptive statistics were used to describe the patients and implants; survival analysis was also performed. The effect of systemic, environmental, and local factors on the survival of the reoperated implants was evaluated. RESULTS: 175 of 10,096 implants in 98 patients were replaced by another implant at the same location (159, 14, and 2 implants at second, third, and fourth surgeries, respectively). Newly replaced implants were generally of similar diameter but of shorter length compared to the previously placed fixtures. A statistically significant greater percentage of lost implants were placed in sites with low bone quantity. There was a statistically significant difference (P = 0.032) in the survival rates between implants that were inserted for the first time (94%) and implants that replaced the ones lost (73%). There was a statistically higher failure rate of the reoperated implants for patients taking antidepressants and antithrombotic agents. CONCLUSIONS: Dental implants replacing failed implants had lower survival rates than the rates reported for the previous attempts of implant placement. It is suggested that a site-specific negative effect may possibly be associated with this phenomenon, as well as the intake of antidepressants and antithrombotic agents.

Bruxism and dental implant treatment complications: a retrospective comparative study of 98 bruxer patients and a matched group.

OBJECTIVES: To analyze the complications of dental implant treatment in a group of patients with bruxism in comparison with a matched group of non-bruxers. MATERIAL AND METHODS: Patients being diagnosed as bruxers were identified within a group of patients consecutively treated with implant-supported prostheses at one specialist clinic, based on the most recent listed sign and symptoms of bruxism according to the International Classification of Sleep Disorders. A diagnostic grading system of "possible," "probable," and "definite" sleep or awake bruxism was used, according to a recent published international consensus. A case-control matching model was used to match the bruxers with a group of non-bruxers, based on five variables. Implant-, prosthetic-, and patient-related data were collected, as well as 14 mechanical complications, and compared between groups. RESULTS: Ninety-eight of 2670 patients were identified as bruxers. The odds ratio of implant failure in bruxers in relation to non-bruxers was 2.71 (95% CI 1.25, 5.88). Considering the same number of patients with the same total number of implants equally distributed between groups, the bruxers group had a higher prevalence of mechanical complications in comparison with the non-bruxers group. CONCLUSIONS: This study suggests that bruxism may significantly increase both the implant failure rate and the rate of mechanical and technical complications of implant-supported restorations. Other risk factors may also have influenced the results.

Survival and Complications of Zygomatic Implants: An Updated Systematic Review.

PURPOSE: To assess the survival rate of zygomatic implants (ZIs) and the prevalence of complications based on previously published studies. MATERIALS AND METHODS: An electronic search of 3 databases was performed in December 2015 and was supplemented by manual searching. Clinical series of ZIs were included. Interval survival rate and cumulative survival rate (CSR) were calculated. The untransformed proportion of complications (sinusitis, soft tissue infection, paresthesia, oroantral fistulas) was calculated by considering the prevalence reported in the studies. RESULTS: Sixty-eight studies were included, comprising 4,556 ZIs in 2,161 patients with 103 failures. The 12-year CSR was 95.21%. Most failures were detected within the 6-month postsurgical period. Studies (n = 26) that exclusively evaluated immediate loading showed a statistically lower ZI failure rate than studies (n = 34) evaluating delayed loading protocols (P = .003). Studies (n = 5) evaluating ZIs for the rehabilitation of patients after maxillary resections presented lower survival rates. The probability of presenting postoperative complications with ZIs was as follows: sinusitis, 2.4% (95% confidence interval [CI], 1.8-3.0); soft tissue infection, 2.0% (95% CI, 1.2-2.8); paresthesia, 1.0% (95% CI, 0.5-1.4); and oroantral fistulas, 0.4% (95% CI, 0.1-0.6). However, these numbers might be underestimated, because many studies failed to mention the prevalence of these complications. CONCLUSION: ZIs present a high 12-year CSR, with most failures occurring at the early stages postoperatively. The main observed complication related to ZIs was sinusitis, which can appear several years after ZI installation surgery.

Dental Implants in Patients Receiving Chemotherapy: A Meta-Analysis.

PURPOSE: To test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants and being versus not being submitted to chemotherapy, against the alternative hypothesis of a difference. METHODS: An electronic search without time or language restrictions was undertaken in May 2014 in PubMed/MEDLINE, Web of Science, Cochrane Oral Health Group Trials Register plus hand-searching. Eligibility criteria included clinical human studies, either randomized or not. RESULTS: Nine publications were included. The results suggested that the insertion of dental implants in patients submitted or not submitted to chemotherapy did not affect the implant failure rates (risk ratio 1.02, 95% confidence interval 0.56-1.85; P = 0.95). Because of lack of enough information, meta-analyses for the outcomes "postoperative infection" and "marginal bone loss" were not performed. CONCLUSION: These results cannot suggest that the insertion of dental implants in patients submitted to chemotherapy may or may not affect the implant failure rates, because of a limited number of published studies, most of them characterized by a low level of specificity and dealing with a limited number of cases without a control group. The reliability and validity of the data collected and the potential for biases and confounding factors are some of the shortcomings of the present study.

Long-term clinical success of minimally and moderately rough oral implants: a review of 71 studies with 5 years or more of follow-up.

PURPOSE: The aim of the review was to compare the long-term clinical success of minimally and moderately rough dental implants in terms of differences in marginal bone loss and survival. MATERIALS AND METHODS: The pertinent literature was searched by using the PubMed database and requesting major manufacturers to provide reports of their commercially available dental implant systems. Clinical reports meeting the following criteria were reviewed: results of at least 5 years of follow-up, availability of baseline and follow-up radiographs including intraoral radiographs, and availability of marginal bone loss measurements from the baseline to the end of the follow-up period (5 years or more). All the recorded data were analyzed statistically. RESULTS: Seventy-one of 1202 articles met the inclusion criteria. Maxillary moderately rough implants were found to have significantly higher long-term survival rates than maxillary minimally rough implants; no such difference was noticed in the mandible. Significant marginal bone loss occurred around all the implants in the first year but stabilized thereafter, indicating the absence of progressive bone loss. CONCLUSION: The dental implant systems commercially available today have good long-term clinical success in terms of survival and marginal bone loss.

Bruxism and Dental Implants: A Meta-Analysis.

PURPOSE: To test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss after the insertion of dental implants in bruxers compared with the insertion in non-bruxers against the alternative hypothesis of a difference. METHODS: An electronic search was undertaken in June 2014. Eligibility criteria included clinical studies, either randomized or not. RESULTS: Ten publications were included with a total of 760 implants inserted in bruxers (49 failures; 6.45%) and 2989 in non-bruxers (109 failures; 3.65%). Due to lack of information, meta-analyses for the outcomes "postoperative infection" and "marginal bone loss" were not possible. A risk ratio of 2.93 was found (95% confidence interval, 1.48-5.81; P = 0.002). CONCLUSIONS: These results cannot suggest that the insertion of dental implants in bruxers affects the implant failure rates due to a limited number of published studies, all characterized by a low level of specificity, and most of them deal with a limited number of cases without a control group. Therefore, the real effect of bruxing habits on the osseointegration and survival of endosteal dental implants is still not well established.

Zygomatic implants: indications, techniques and outcomes, and the zygomatic success code.

The zygoma implant has been an effective option in the management of the atrophic edentulous maxilla as well as for maxillectomy defects. Brånemark introduced the zygoma implant not only as a solution to obtain posterior maxillary anchorage but also to expedite the rehabilitation process. The zygoma implant is a therapeutic option that deserves consideration in the treatment-planting process. This paper reviews the indications for zygoma implants and the surgical and prosthetic techniques (including new developments) and also reports on the clinical outcome of the zygomatic anatomy-guided approach. An overview of conventional grafting procedures is also included. Finally, a Zygoma Success Code, describing specific criteria to score the success of rehabilitation anchored on zygomatic implants, is proposed.

A randomized and controlled clinical trial of two different compositions of deproteinized bovine bone and autogenous bone used for lateral ridge augmentation.

OBJECTIVE: The aim of the study was to radiologically and histologically evaluate the graft healing and volumetric changes after lateral augmentation with two different compositions of deproteinized bovine bone (DPBB) and autogenous bone (AB). MATERIAL AND METHODS: Thirteen patients with a mean age of 59.6 ± 12.1 years (six men and seven women) were included in this randomized and controlled trial, designed as a split-mouth study. Ten edentulous and four partially edentulous jaws with an alveolar ridge width of ≤4 mm were laterally augmented with a graft composition of 60 : 40 (DPBB/AB) on one side and 90 : 10 (DPBB/AB) on the contralateral side. Cone beam computed tomography (CB/CT) was obtained immediately postoperatively and after a healing period of 7.5 months. Width changes were measured on CB/CT scans. After a mean healing period of 8.1 months (range, 7.9-8.3), biopsies were retrieved perpendicular to the crest from each graft by means of a trephine bur. Histomorphometry was performed, and the following variables were recorded: Ingrowth of new bone (percentage of total graft width), percentage of DPBB, bone and soft tissue, and percentage of DPBB particles in contact with bone. RESULTS: The mean gained width of the alveolar crest after 7.5 months was significantly more for the 60 : 40 mixture compared with the 90 : 10 mixture, 3.5 (±1.3) mm and 2.9 (±1.3) mm, respectively. There was a significant difference in graft width reduction between 60 : 40 and 90 : 10 after 7.5 months, 37 (±19.9)% and 46.9 (±23.5)%, respectively. New bone ingrowth had occurred in 82.1 (±23.3)% and 82.3 (±26.6)% of the graft, respectively. There were no statistical differences between fractions of different tissues between the 90 : 10 and 60 : 40 compositions. However, there were significantly more soft tissue and less new bone formation closer to the periosteum compared with the graft portion closer to the residual bone in both 60 : 40 and 90 : 10 compositions. CONCLUSIONS: There was significantly less graft width reduction with a mixture of 60 : 40 (DPBB/AB) compared with a mixture of 90 : 10 composition, but the results from the histomorphometry showed no statistical differences comparing the groups.

A Prospective Report of the Clinical Outcome of TiUnite Implants at 20 Years of Follow-up.

PURPOSE: To present a survival analysis of 133 consecutively placed moderately rough implants, all with a total follow-up of 20 years. MATERIALS AND METHODS: A total of 133 implants of the same brand placed in 46 patients at the same county clinic in Sweden were followed up prospectively over 20 years and analyzed for survival and bone height, the latter evaluated in periapical radiographs. RESULTS: A total of 7 implants failed, 4 of which were in the same patient. Implant failure was associated with a combination of smoking and bruxism in 5 of the 7 failed cases. A 20-year survival rate of 94.7% was observed. Average marginal bone loss (MBL) at 20 years of follow-up was 0.543 ± 1.193 mm, with 9 implants having more than 2 mm of MBL. A total of 20 patients with 25 implants dropped out of the study; however, if death of the patient is excluded as a dropout reason, only 3 implants in 3 patients were unaccounted for. CONCLUSIONS: Good clinical results in the 95% survival range were observed with moderately rough implants over a 20-year follow-up period.

Aseptic Silk Ligatures Induce Bone Resorption Around Titanium Implants: A 12-Week Pilot Study in Rabbits.

PURPOSE: Marginal bone resorption (MBR) around dental implants may sometimes be a self-limiting condition due to balancing immunologic reactions against utilized materials rather than a progressive bacterial infection. Contrary to previous assumptions from ligature-induced experimental peri-implantitis studies, a recent 8-week experiment by the present authors showed that marginal ligatures trigger an inflammatory immune response, resulting in bone resorption around implants in the absence of plaque. The present study aimed to investigate whether this inflammatory/immunologic reaction attenuates or progresses toward implant failure after a longer healing time (12 weeks). MATERIALS AND METHODS: Sterile silk ligatures were placed around the top of titanium (Ti) implants and compressed against the femoral cortical bone plate of six rabbits. A nonligated implant was used as a control. After 12 weeks of submerged healing, ground sections of implants and surrounding tissues were investigated with light microscopy. The marginal soft tissues were also analyzed using selected quantitative polymerase chain reaction (qPCR) markers. RESULTS: Histologically, the ligatures were outlined by immune cells, including multinucleated giant cells (MNGCs), with adjacent fibrous encapsulation and resorbed peripheral bone that contrasted from the osseointegrated nonligated control implants. The difference in expression of qPCR markers was not significant, but > two-fold upregulation of markers CD11b, IL1ß, ARG1, NCF1, and CD4 and > twofold downregulation of CD8 indicated a mild, focal inflammatory/immune response against the ligatures compared to controls, with upregulation of M1 and M2 macrophages, neutrophils, and helper T-cells as well as downregulation of killer T cells. Further, the bone formation markers OC and ALPL were > two-fold downregulated (consistent with the lack of osseointegration of the ligatures) compared to control implants. CONCLUSIONS: Marginal silk ligatures trigger an inflammatory/immune response and aseptic bone resorption around implants. Compared to the previous 8-week study, the inflammatory reaction against the silk appears to attenuate with time, with only a mild persisting inflammation that may block osseointegration; instead, a fibrous tissue encapsulation-type reaction is maintained. This may explain why traditional ligature experiments have required regular exchange of ligatures for the bone resorption to progress.

Residual Debris within Internal Features of As-received New Dental Implants.

PURPOSE: To investigate residual debris within internal features of new 'as received' dental implants. MATERIALS AND METHODS: A total of 15 new dental implants representing various dental implant brands were obtained in sealed containers from the manufacturers. Batch numbers and implant types were documented. In a controlled setting, implants were carefully unpacked, and their internal aspects were visually examined. Further analysis involved light microscopy imaging to document and photograph any foreign material. The internal aspect of the implants were sampled with both an endodontic paper cone and a fine bristle brush swab. These were inserted into the implant, rotated three times, then removed and examined under a microscope at 30x magnification. Post sampling some of the brushes/swabs were washed with alcohol to remove debris that could be further examined under magnification. RESULTS: Inspection of the implants without magnification revealed no visible foreign materials. However, under light microscopy (x10 and x30), all 15 implants exhibited small black particles at various internal sites, including connections, threads, and deep within screw channels. Swabs evaluated at magnification detected what appeared to be metal particles in all 15 implants, ranging from distinct metal shards to smaller particles. CONCLUSION: This study suggests that implant manufacturers have not effectively removed all machining debris from within implant bodies, potentially producing prosthetic and clinical complications.

Extracorporeal Shockwave Therapy (ESWT), a Novel Method for Transferring Oral Implant Primary Failures to Final Clinical Success: A Test Case Report Followed up over More than 6 Years.

PURPOSE: To evaluate the feasibility of reversing a primary failure through therapeutic mechanical stimulation induced by transcutaneous application of acoustic waves (ESWT) in the peri-implant tissues. Materials and Μethods: This clinical report evaluates the outcome of a new protocol proposed to treat a primary failure (loosened oral implant); application of three cycles of ESWT, once session per week for 3 consecutive weeks, with an equivalent positive energy of 0,18 mJ/mm² (therapeutic dose: 2000 impulses/ 8Hz/ 4.0 bar). Standardized intraoral radiographs, Cone Beam Computed Tomography (CBCT), Implant Stability Quotient (ISQ) and clinical evaluations were performed. RESULTS: It was possible to verify a progressive increase in the ISQ value after the ESWT protocol; 17 (initial), 46 (after two months) and 68 (after four months), which led to successful implant prosthetic rehabilitation (35 N/cm measured). Our evaluation at 6 years of follow-up confirms that the new bone-implant interface is preserved and ESWT as a safe non-invasive treatment. CONCLUSION: In the context of the new dynamic model of osseointegration, the Foreign Body Equilibrium (FBE), this represents the first report of a host-Implant equilibrium re-established after an early failure process. However, it is necessary to perform studies to determine both the medical device and the most effective therapeutic range for clinical applications of this technology in oral implantology.

A novel technique for tailored surface modification of dental implants - a step wise approach based on plasma immersion ion implantation.

OBJECTIVES: A novel technique based on plasma immersion ion implantation (PIII) is presented to modify titanium implant surfaces. MATERIALS AND METHODS: Initially, the implants are cleaned with argon to remove contaminants and the nanostructures are created by the bombardment of the surface with a mix of noble gases. Desired crystal structure of the titanium is obtained by the implantation of oxygen on the contaminant-free surface with particular nanostructures. RESULTS: In this study, turned implants modified by PIII revealed a high density of rutile-TiO2 nanostructures. Turned implants used as control revealed mainly microstructures and amorphous crystal structure. Surface roughness values were similar at the microscale for both turned and turned + PIII implants. Bone response was evaluated by removal torque tests of implants placed in the rabbit tibia and femur. After 4 weeks of healing, turned + PIII demonstrated higher removal torque values (P = 0.001) compared to turned implants. CONCLUSIONS: The presence of rutile-TiO2 nanostructures may explain the improved bone formation to turned + PIII implants.

Implant coatings: new modalities for increased osseointegration.

PURPOSE: To present new techniques for implant coatings, biological tissue response to them, and, if applicable, clinical outcome. METHODS: A search for publications was done in PubMed using search words such as coated dental implants, clinical outcome, dental implant coatings and combinations thereof. Further, a manual search was done. 216 papers were found; the selection was directed towards in vivo investigations. RESULTS: Several different coatings are described in the literature, many of them with the purpose to be bioactive. Such surface coatings include hydroxyapatite, bioglass, proteins, polysaccharides and drugs. The majority of the publications are evaluations in vitro; most of the in vivo studies are directed to implant incorporation in bone. Rather few exist that use a coat to promote soft tissue adhesion or prevention of infection.

Surface characterization and clinical review of two commercially available implants.

PURPOSE: To characterize topographically and chemically the surfaces of 2 commercially available implants. Furthermore, to gather an overview of the clinical results of these implant systems. MATERIALS AND METHODS: Two commercially available oral implants were analyzed using optical interferometry, scanning electron microscopy, and energy dispersive spectroscopy. In addition, a literature search for all the clinical articles on the same implants was performed. RESULTS: No significant differences of topographical parameters were found between the 2 implants, except for the hybrid parameter Sdr presenting significant higher values for the Ankylos implants. Both surfaces had a homogenous microporosity. At higher magnifications of scanning electron microscope images, evenly distributed nanostructures (approximately 10 nm) were visible. Chemically, mainly titanium, oxygen and carbon were detected. Fifty-six clinical articles were included for the review. The implant survival rates (minimum follow-up: 5 years) ranged between 87.7% and 100%. CONCLUSIONS: The examined commercially available implants showed a moderately rough surface, with a homogenous microporosity. Nanofeatures were detected on the surface of both implants. The clinical performances of these implants were comparable to that of other commercialized implant systems.

The effect of calcium ion concentration on the bone response to oxidized titanium implants.

AIM: To investigate the effect of calcium concentration on the bone tissue response to Ca-incorporated titanium implants. MATERIALS AND METHODS: Two titanium surfaces containing 4.2% and 6.6% calcium were prepared using the micro-arc oxidation process. The implants were inserted in the tibia of nine New Zealand White rabbits. After 6 weeks of healing, the bone response to the implants was quantitatively compared by biomechanical and histomorphometrical measurements. RESULTS: Ca 4.2% and Ca 6.6% containing implants revealed no distinctive differences in their qualitative surface chemistry; chemical bonding state of Ca in titanium oxide was mainly calcium titanates. No significant differences were observed between two implants in peak removal torque and shear strength comparisons (P>0.05). Histomorphometrical analyses presented no significant differences in bone-metal contact, bone area and newly formed bone measurements between two implants (P>0.05). CONCLUSIONS: From biomechanical and histomorphometrical measurements, the two calcium concentrations in this study did not differ significantly with respect to their influence on the bone tissue response. This similar bone response in rabbit tibiae may be explained by the similarity of the qualitative Ca chemistry in titanium surfaces.

Implications of considering peri-implant bone loss a disease, a narrative review.

BACKGROUND: Peri-implantitis has been suggested to cause significant increasing proportions of implant failure with increasing time. PURPOSE: To assess whether implant failure rates in long term studies are matching the supposed high prevalence of peri-implantitis. MATERIAL AND METHODS: This paper is written as a narrative review of the long-term clinical investigations available in the literature. RESULTS: Some implant systems have seen unacceptable marginal bone loss figures with time coupled to increased implant failure rates, resulting in the withdrawal of these systems. The reasons for such mishap are generally unknown, with the exception of one system failure that was found to be due to improper clinical handling. Modern, moderately rough implant systems have functioned excellently over 10-15 years of follow up with minor problems with marginal bone loss and implant failure rates within a few per cent. Machined implants have functioned adequately over 20-30 years of follow up. Implant failures occur predominantly during the first few years after implant placement. No significant increase of implant failures has been observed thereafter over 20-30 years of follow up. Over the years of our new millennium, scientific and technical advances have allowed the discovery of numerous molecular pathways and cellular interactions between the skeletal and immune system promoting the development of the interdisciplinary field called osteoimmunology. Nowadays, this knowledge has not only allowed the emergence of new etiologic paradigms for bone disease but also a new dynamic approach on the concept of osseointegration and MBL around oral implants, re-evaluating our older disease oriented outlook. This facilitates at the same time the emergence of translational applications with immunological perspectives, scientific approaches based on omics sciences, and the beginning of an era of personalized dental implant therapy to improve the prognosis of oral implant treatment. CONCLUSIONS: Oral implant systems have been found to function with very good clinical outcome over follow-up times of 20-30 years. Registered implant failures have occurred predominantly during the first few years after implantation, and there has been no significant increase in late failures due to peri-implantitis.

Quality Assessment of Five Randomly Chosen Ceramic Oral Implant Systems: Cleanliness, Surface Topography, and Clinical Documentation.

PURPOSE: After some initial setbacks in the 1970s, ceramic implants seem to be a promising alternative to titanium implants. Since the surface of an implant system represents the interface to surrounding biologic structures, the study focuses on cleanliness and surface topography. Clinical documentation of the corresponding systems completes the picture and allows a better evaluation of zirconia implant systems. MATERIALS AND METHODS: Five different ceramic implant systems were selected randomly and purchased via blind-shopping: Z5s (Z-Systems), ZiBone (COHO), W implant (TAVDental), ceramic. implant (vitaclinical), and BioWin!/Standard Zirkon Implantat (Champions-Implants/ZV3 system). Three samples of each implant system underwent scanning electron microscopy (SEM) imaging and elemental analysis (EDS). Where appropriate, subsequent Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was performed to identify the chemical nature of impurities. Surface topography was evaluated, and a search for clinical trials in the PubMed database, on the websites and by written request to each dental implant manufacturer, was performed. RESULTS: Surfaces of Champions implants (ZV3) and Z-Systems implants were relatively clean, whereas the other investigated surfaces of vitaclinical, TAV Dental, and ZiBone implants all displayed organic contaminations on their surfaces. Four of the investigated ceramic implants showed a moderately rough implant surface. Only the vitaclinical ceramic.implant had minimal surface roughness. Three ceramic designs-vitaclinical, ZV3, and Z-Systems-had clinical trials documented with up to 3 years of follow-up and results varying between 82.5% and 100% survival. TAV Dental W and ZiBone implant systems lacked properly conducted clinical recording of results. CONCLUSION: The results of this study showed that it is technically possible to produce zirconia implants that are largely residue-free. On the other hand, the variety of significant residues found in this analysis raises concerns, as contamination may lead to undesirable biologic effects. The lack of clinical studies in peer-reviewed journals does not seem to be relevant for the approval of marketing, nor does the lack of surface cleanliness. In the authors' opinion, a critical analysis of these aspects should be included in a more stringent future analysis prior to the marketing of oral implant systems.