Background Marginal bone resorption has by some been identified as a "disease" whereas in reality it generally represents a condition. Purpose The present article is a comparison between oral and orthopedic implants, as previously preferred comparisons between oral implants and teeth seem meaningless. Materials and Methods The article is a narrative review on reasons for marginal bone loss. Results and Conclusions The pathology of an oral implant is as little related to a tooth as is pathology of a hip arthroplasty to a normally functioning, pristine hip joint. Oral as well as orthopedic implants are recognized as foreign bodies by the immune system and bone is formed, either in contact or distance osteogenesis, to shield off the foreign materials from remaining tissues. A mild immune reaction coupled to a chronic state of inflammation around the implant serve to protect implants from bacterial attacks. Having said this, an overreaction of the immune system may lead to clinical problems. Marginal bone loss around oral and orthopedic implants is generally not dependent on disease, but represents an immunologically driven rejection mechanism that, if continuous, will threaten implant survival. The immune system may be activated by various combined patient and clinical factors or, if rarely, by microbes. However, the great majority of cases with marginal bone loss represents a temporary immune overreaction only and will not lead to implant failure due to various defense mechanisms.

Background A consensus meeting was arranged to critically analyze whether the high figures of peri-implantitis at machined implants that recently have been reported in the literature are valid also for modern implants. Purpose The aims of this paper were to present the outcomes from the consensus meeting and to evaluate recent long-term clinical studies on modern implants with regard to frequency of peri-implant infection. Materials and Methods Ten different studies of three modern implant brands of moderately rough surfaces with 10-year or longer follow-up times were found through a PubMed and manual search. Results It was concluded that bleeding on probing or probing depths are weak indicators of crestal bone loss (CBL); that CBL occurs for many other reasons than infection; that implant-, clinician-, and patient-related factors contribute to CBL; and that modern oral implants outperform older devices. Based on a literature search, the frequency of implants with reported peri-implant infection and significant bone loss leading to implant removal or other surgical intervention was on average 2.7% during 7 to 16 years of function. Conclusion The summed frequency of peri-implantitis and implant failure is commonly less than 5% over 10 years of follow-up for modern implants when using established protocols.

Background: The discrepancy between some scientific views and the daily clinical experience with dental implants has made the topic of "periimplantitis" highly controversial, especially the discussion whether "periimplantitis" should even be considered a "disease" or whether marginal bone loss instead would represent a complication of having a foreign body placed in the oral cavity. Purpose: The aim of the present paper was to present the outcomes from a consensus meeting on "peri-implantitis" in Rome, Italy (January 8-10, 2016). Materials and Methods: Seventeen clinical scientists were invited to, based on prepared reviews of the literature, discuss topics related to "periimplantitis." Results and conclusions: Oral implants may lose bone or even display clinical failure. However, progressive bone loss threatening implant survival is rare and limited to a percent or two of all implants followed up over 10 years or more, provided that controlled implant systems are being used by properly trained clinicians. There is very little evidence pointing to implants suffering from a defined disease entity entitled "peri-implantitis." Marginal bone loss around implants is in the great majority of cases associated with immune-osteolytic reactions. Complicating factors include patient genetic disorders, patient smoking, cement or impression material remnants in the peri-implant sulcus, bacterial contamination of the implant components and technical issues such as loose screws, mobile components or fractured materials. These reactions combine to result in cellular responses with the end result being a shift in the delicate balance between the osteoblast and the osteoclast resulting in bone resorption. However, the great majority of controlled implants display a foreign body equilibrium resulting in very high survival rates of the implants over long term of follow-up.

Background When a foreign body is placed in bone or soft tissue, an inflammatory reaction inevitably develops. Hence, osseointegration is but a foreign body response to the implant, which according to classic pathology is a chronic inflammatory response and characterized by bone embedding/separation of the implant from the body. Purpose The aim of this paper is to suggest an alternative way of looking at the reason for marginal bone loss as a complication to treatment rather than a disease process. Materials and Methods The present paper is authored as a narrative review contribution. Results The implant-enveloping bone has sparse blood circulation and is lacking proper innervation in clear contrast to natural teeth that are anchored in bone by a periodontal ligament rich in blood vessels and nerves. Fortunately, a balanced, steady state situation of the inevitable foreign body response will be established for the great majority of implants, seen as maintained osseointegration with no or only very little marginal bone loss. Marginal bone resorption around the implant is the result of different tissue reactions coupled to the foreign body response and is not primarily related to biofilm-mediated infectious processes as in the pathogenesis of periodontitis around teeth. This means that initial marginal bone resorption around implants represents a reaction to treatment and is not at all a disease process. There is clear evidence that the initial foreign body response to the implant can be sustained and aggravated by various factors related to implant hardware, patient characteristics, surgical and/or prosthodontic mishaps, which may lead to significant marginal bone loss and possibly to implant failure. Admittedly, once severe marginal bone loss has developed, a secondary biofilm-mediated infection may follow as a complication to the already established bone loss. Conclusions The present authors regard researchers seeing marginal bone loss as a periodontitis-like disease to be on the wrong track; the onset of marginal bone loss around oral implants depends in reality on a dis-balanced foreign body response.

Background Oral implants have displayed clinical survival results at the 95%-99% level for over 10 years of follow up. Nevertheless, some clinical researchers see implant disease as a most common phenomenon. Oral implants are regarded to display disease in the form of mucositis or peri-implantitis. One purpose of the present article is to investigate whether a state of disease is necessarily occurring when implants display soft tissue inflammation or partially lose their bony attachment. Another purpose of this article is to analyze the mode of defense for implants that are placed in a bacteria rich environment and to analyze when an obtained steady state between tissue and the foreign materials is disturbed. Materials and Methods The present article is authored as a narrative review contribution. Results Evidence is presented that further documents the fact that implants are but foreign bodies that elicit a foreign body response when placed in bone tissue. The foreign body response is characterized by a bony demarcation of implants in combination with a chronic inflammation in soft tissues. Oral implants survive in the bacteria-rich environments where they are placed due to a dual defense system in form of chronic inflammation coupled to immunological cellular actions. Clear evidence is presented that questions the automatic diagnostics of an oral implant disease based on the finding of so called mucositis that in many instances represents but a normal tissue response to foreign body implants instead of disease. Furthermore, neither is marginal bone loss around implants necessarily indicative of a disease; the challenge to the implant represented by bone resorption may be successfully counteracted by local defense mechanisms and a new tissue-implant steady state may evolve. Similar reactions including chronic inflammation occur in the interface of orthopedic implants that display similarly good long-term results as do oral implants, if mainly evaluated based on revision surgery in orthopedic cases. The most common mode of failure of orthopedic implants is aseptic loosening which has been found coupled to a reactivation of the inflammatory- immune system. Conclusions Implants survive in the body due to balanced defense reactions in form of chronic inflammation and activation of the innate immune system. Ten year results of oral and hip /knee implants are hence in the 90+ percentage region. Clinical problems may occur with bone resorption that in most cases is successfully counterbalanced by the defense/healing systems. However, in certain instances implant failure will ensue characterized by bacterial attacks and/or by reactivation of the immune system that now will act to remove the foreign bodies from the tissues.

Background The understanding of mechanisms of osseointegration as well as applied knowledge about oral implant surfaces are of paramount importance for successful clinical results. Purpose The aim of the present article is to present an overview of osseointegration mechanisms and an introduction to surface innovations with relevance for osseointegration that will be published in the same supplement of Clinical Implant Dentistry and Related Research. Materials and Methods The present article is a narrative review of some osseointegration and implant surface-related details. Results and Conclusions Osseointegration has a changed definition since it is realized today that oral implants are but foreign bodies and that this fact explains osseointegration as a protection mechanism of the tissues. Given adequate stability, bone tissue is formed around titanium implants to shield them from the tissues. Oral implant surfaces may be characterized by microroughness and nanoroughness, by surface chemical composition and by physical and mechanical parameters. An isotropic, moderately rough implant surface such as seen on the TiUnite device has displayed improved clinical results compared to previously used minimally rough or rough surfaces. However, there is a lack of clinical evidence supporting any particular type of nanoroughness pattern that, at best, is documented with results from animal studies. It is possible, but as yet unproven, that clinical results may be supported by a certain chemical composition of the implant surface. The same can be said with respect to hydrophilicity of implant surfaces; positive animal data may suggest some promise, but there is a lack of clinical evidence that hydrophilic implants result in improved clinical outcome of more hydrophobic surfaces. With respect to mechanical properties, it seems obvious that those must be encompassing the loading of oral implants, but we need more research on the mechanically ideal implant surface from a clinical aspect.

BackgroundIt has been reported that titanium-zirconium alloy with 13-17% zirconium (TiZr1317) implants show higher biomechanical stability and bone area percentage relative to commercially pure titanium (cpTi) grade 4 fixtures. PurposeThis study aimed to determine whether the higher stability for TiZr1317 implants is associated with higher mechanical properties of remodeling bone in the areas around the implants. Materials and MethodsThis study utilized 36 implants (n=18: TiZr1317, n=18: cpTi), which were placed in the healed ridges of the mandibular premolar and first molar of 12 mini pigs (n=3 implants/animal). After 4 weeks in vivo, the samples were retrieved, and resin-embedded histologic sections of approximately 100m in thickness were prepared. In order to determine the nanomechanical properties, nanoindentation (n=30 tests/specimen) was performed on the bone tissue of the sections under wet conditions with maximum load of 300N (loading rate: 60N/s). ResultsThe mean (standard deviation) elastic modulus (E) and hardness (H) for the TiZr1317 group were 2.73 +/- 0.50GPa and 0.116 +/- 0.017GPa, respectively. For the cpTi group, values were 2.68 +/- 0.51GPa and 0.110 +/- 0.017GPa for E and H, respectively. Although slightly higher mechanical properties values were observed for the TiZr1317 implants relative to the cpTi for both elastic modulus and hardness, these differences were not significant (E=p>0.75; H=p>0.59). ConclusionsThe titanium-zirconium alloy used in this study presented similar degrees of nanomechanical properties to that of the cpTi implants.

Background: Elevation of the schneiderian membrane, during maxillary sinus floor augmentation (MSFA) may theoretically result in devitalization of adjacent teeth, which are in a close spatial relationship to the sinus floor. Purpose: To assess retrospectively the probability of devitalization of teeth adjacent to the osteotomy site after MSFA in a relatively large number of patients. Materials and Methods: All MSFA procedures, performed at a university oral surgery clinic within a time period of 10 years, were assessed on the following eligibility criteria: (1) presence of vital teeth (ie, not root canal treated and no periapical radiolucency on a panoramic radio- graph taken just after MSFA), (2) presence of a 3 to 12 months postoperative radiograph of the teeth adjacent to the osteotomy site displaying the root apices, and (3) complete medical records up to at least 12 months postoperatively. The radiographs of the different time points were compared and any changes in the radiographic status of the adjacent teeth (eg, develop- ment of a periapical lesion, root canal treatment, etc.) were recorded and the spatial relationship of the adjacent teeth to the maxillary sinus classified. Results: Out of 684 MSFAs, 257 fulfilled the inclusion criteria and involved 357 adjacent teeth, of which 221 presented close to and/or intimate relationship to the sinus. In only a single case, tooth vitality might have been lost due to the procedure. Thus, the probability for tooth devitali- zation for teeth with close to and/or intimate spatial relationship to the sinus floor ranged from 0.45% to 0.7%. Conclusions: Even for teeth with apices very close to and/or intimately related to the sinus tooth devitalization after MSFA is an extremely rare complication; that is, the probability of tooth devitalization after MSFA is ≤0.7%.

PURPOSE: The aim of this study was to prospectively evaluate the survival rate of splinted and immediately loaded Straumann sandblasted, large-grit, acid-etched, solid-screw dental implants in the edentulous maxilla after 32 months of loading. MATERIALS AND METHODS: Twenty-eight patients (mean age 63 years) with edentulous maxillae received 168 implants (six each) and an implant-supported fixed interim prosthesis within 24 hours after surgery. After a mean healing time of 15 weeks, the patients received permanent screw-retained prostheses. Clinical and radiological examinations were made at implant placement and after 8, 20, and 32 months of loading. All permanent prostheses were removed at the 32-month follow-up; implant stability was checked with a torque device, and the implant stability quotient was determined with resonance frequency analysis. RESULTS: Mean marginal bone loss from baseline to 8 months after loading was 1.6 mm (SD 1.16; p = .094), from 8 to 20 months 0.41 mm (SD 0.63; p = .094), and from 20 to 32 months 0.08 mm (SD 0.49; p = .039). The 32-month cumulative survival rate was 98.2%. CONCLUSIONS: The 32-month survival of solid-screw implants - immediately loaded within 24 hours after placement - was similar to survival rates reported for solid-screw implants with conventional loading. Immediate loading and splinting of implants in the edentulous maxilla is a viable treatment alternative.

PURPOSE: The aim of this study was to assess the effect of implant coating with laminin-1 on the early stages of osseointegration in vivo.

MATERIALS AND METHODS: Turned titanium implants were coated with the osteoprogenitor-stimulating protein, laminin-1 (TL). Their osteogenic performance was assessed with removal torque, histomorphometry, and nanoindentation in a rabbit model after 2 and 4 weeks. The performance of the test implants was compared with turned control implants (T), alkali- and heat-treated implants (AH), and AH implants coated with laminin-1.

RESULTS: After 2 weeks, TL demonstrated significantly higher removal torque as compared with T and equivalent to AH. Bone area was significantly higher for the test surface after 4 weeks, while no significant changes were detected on the micromechanical properties of the surrounding bone.

CONCLUSIONS: Within the limitations of this study, our results suggest a great potential for laminin-1 as a coating agent. A turned implant surface coated with laminin-1 could enhance osseointegration comparable with a bioactive implant surface while keeping the surface smooth.

PURPOSE: To compare marginal bone loss (MBL) around dental implants in a group of bruxers in relation to a matched group of non-bruxers.

METHODS: The present record-based retrospective study included patients selected from individuals treated with dental implants at one specialist clinic in Malmö. Only implants not lost and with baseline radiographs taken within 12 months after implant placement and with a minimum of 36 months of radiological follow-up were considered for inclusion. Univariate linear regression models and a linear mixed-effects model were performed.

RESULTS: Two hundred and four patients (104 bruxers, 100 non-bruxers), with a total of 811 implants (416 in bruxers, 395 in non-bruxers) were included in the study. The results of the linear mixed-effects model suggested that bruxism, smoking, age, region of the jaws, implant diameter, and prosthesis type had a statistically significant influence on MBL over time. Individuals who are both bruxers and smokers showed greater MBL when compared to individuals who are either a bruxer or smoker, or neither (p < 0.001).

CONCLUSIONS: Bruxism is suggested to increase the risk of MBL over time, as well as higher age, smoking, and the combination of bruxism and smoking. Other factors that showed a correlation with increased MBL were implant diameter, region of the jaws, and prosthesis type, but it is not possible to draw robust conclusions for these factors, as the categories of these variables were very unbalanced.

Background: Immediate loading of full-arch restorations yields good results in selected cases, but long-term follow-up and the outcome in compromised bone are scarcely evaluated. Purpose: To evaluate immediately loaded Osseotite implants (Biomet 3i, Palm Beach, FL, USA) installed in healed or grafted bone, with regard to implant survival and peri-implant bone loss up to 7 years in function. Materials and Methods: Information was retrospectively retrieved from 83 patients' records with 749 Osseotite implants supporting immediately loaded semipermanent full-arch acrylic restorations. Five hundred sixty-eight (75.8%) implants were placed in healed bone and 181 (24.2%) in augmented bone, regenerated with sinus lifting and/or onlay/inlay grafts with/without biomaterials and membranes. Implant survival and success based on radiological peri-implant bone loss were registered. Wilcoxon rank sum tests evaluated peri-implant bone loss in compromised versus healed bone or between jaws or time intervals with p < .05 as statistically significant. Results: Sixteen of 749 implants failed (2.1%), 11/343 in maxilla (3.2%) and 5/406 (1.2%) in mandible. After 7 years, the cumulative failure rate was 9%. Mean peri-implant bone loss increased to 1.2 mm (SD 1.0) during the first 2 years but remained unchanged thereafter. Around implants in grafted bone, on average, 0.3 mm more bone loss was found. Conclusion: The Osseotite implants offer a predictable long-term outcome in terms of implant survival and stable peri-implant bone under immediate loading even in grafted bone. However, the high incidence of technical repair because of fractures of the semipermanent provisionals requires attention because it may be negative from a cost-benefit perspective. Implants in grafted bone show a tendency to a more pronounced initial bone remodeling without clinical consequence in the long term.

Background: The All-on-4® concept is widely applied for full-arch rehabilitations, using two tilted and two axially loadedimplants in order to overcome anatomical constraints.Purpose: The aim of this study was to assess the survival and individual success of implants immediately loaded with anAll-on-4 full-arch screw-retained prosthetic bridge i n fully edentulous mandibles or maxillae over up to 3 years.Materials and Methods: In total, 20 patients with atrophic jaws (9 maxillae, 11 mandibles) were treated with computer-guided flapless surgery and immediately provided with a provisional bridge. The final prosthesis was delivered after6 months. In total, 80 TiUnite™ Brånemark implants were placed. Radiographs were taken after surgery and 1 and 3 yearslater.Results: A 3-year survival rate of 100% was seen for all implants, both in lower and in upper jaw. None of the temporaryor definite prostheses were lost over the follow-up period of 3 years. After 1 year, the mean bone loss was 1.13 mm (SD 0.94;range −0.1 to 3.8), and after 3 years, it was 1.61 mm (SD 1.40; range 0 to 5). The mean bone loss between the 1-year and3-year follow-ups was 0.48 mm (SD 0.66; range −1.2 to 3.6). This difference was statistically significant (p < .001), indicativeof ongoing bone loss. Twenty-six percent of the implants had bone loss above 1.5 mm after 1 year, but after 3 years, 30%of the implants had already lost more than 1.9 mm.Conclusion: The implant and prosthetic survival was 100%, and patients benefited from the All-on-4 treatment. However,unacceptable ongoing bone loss was seen in 49.2% of the patients; this may be a warning sign for future problems and needsclinical attention. Overloading and surgery-related aspects need to be investigated as potential explanations.

PURPOSE: To describe the early bone tissue response to implants with and without micro threads designed to the full length of an oxidized titanium implant. MATERIALS AND METHODS: A pair of two-dimensional finite element models was designed using a computer aided three-dimensional interactive application files of an implant model with micro threads in between macro threads and one without micro threads. Oxidized titanium implants with (test implants n=20) and without (control implants n=20) micro thread were prepared. A total of 12 rabbits were used and each received four implants. Insertion torque while implant placement and removal torque analysis after 4 weeks was performed in nine rabbits, and histomorphometric analysis in three rabbits, respectively. RESULTS: Finite element analysis showed less stress accumulation in test implant models with 31Mpa when compared with 62.2 Mpa in control implant model. Insertion and removal torque analysis did not show any statistical significance between the two implant designs. At 4 weeks, there was a significant difference between the two groups in the percentage of new bone volume and bone-to-implant contact in the femur (p< .05); however, not in the tibia. CONCLUSIONS: The effect of micro threads was prominent in the femur suggesting that micro threads promote bone formation. The stress distribution supported by the micro threads was especially effective in the cancellous bone.

Background Traditionally, before placing dental implants, the compromised teeth are removed and the extraction sockets are left to heal for several months. To preserve the alveolar bone level from the collapse caused by healing and to reduce treatment time in situations in which tooth extraction precedes implant placement, some clinicians began to install the implant immediately into the postextraction socket without waiting for the site to heal. Purpose The purpose of this study was to review the literature regarding treatment outcomes of immediate implant placement into sites exhibiting pathology after clinical procedures to perform the decontamination of the implant's site. The following questions were raised: Does the presence of periodontal or endodontic infection affect immediate implant placement success? What is suggested to address the infection in the socket prior to immediate placement? Materials and Methods An electronic search in PubMed (U.S. National Library of Medicine, Bethesda, MD, USA) was undertaken in March 2013. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included both animal and human studies, and excluded any review and case reports articles. The publication's intervention had to have been implant placement into a site classified as having an infection (periapical, endodontic, perioendodontic, and periodontal). Results The search strategy initially yielded 706 references. Thirty-two studies were identified within the selection criteria, from which nine were case reports and review articles and were excluded. Additional hand-searching of the reference lists of selected studies yielded five additional papers. Conclusions The high survival rate obtained in several studies supports the hypothesis that implants may be successfully osseointegrated when placed immediately after extraction of teeth presenting endodontic and periodontal lesions, provided that appropriate clinical procedures are performed before the implant surgical procedure such as meticulous cleaning, socket curettage/debridement, and chlorhexidine 0.12% rinse. However, more randomized controlled clinical trials with a longer follow-up are required to confirm this procedure as a safe treatment. Moreover, the outcome measures were not related to the type of infection; the classification of infection was often vague and varied among the studies. The benefits of antibiotic solution irrigation and systemic antibiotic administration in such conditions are not yet proved and remain unclear.

Background: Very long-term follow-up of oral implants is seldom reported in the literature. Purpose: To assess oral implant failure rates and marginal bone loss (MBL) of patients followed up for a minimum of 20 years. Materials and Methods: Implants placed in patients followed up for 20+ years were included. Descriptive statistics, survival analyses, generalized estimating equations were performed. Three-hundred implants were randomly selected for MBL. Results: 1,045 implants (227 patients) were included. Implant location, irradiation, and bruxism affected the implant survival rate. Thirty-five percent of the failures occurred within the first year after implantation, and another 26.8% in the second/third year. There was a cumulative survival rate of 87.8% after 36 years of follow-up. In the last radiological follow up, 35 implants (11.7%) had bone gain, and 35 implants (11.7%) presented at least 3 mm of MBL. Twenty-six out of 86 failed implants with available radiograms presented severe MBL in the last radiological register before implant failure. Conclusions: Most of the implant failures occurred at the first few years after implantation, regardless of a very long follow up. MBL can be insignificant in long-term observations, but it may, nevertheless, be the cause of secondary failure of oral implants in some cases.

Background: Some studies indicated that implant failures are commonly concentrated in few patients. Purpose: To identify and analyze cluster behavior of dental implant failures among subjects of a retrospective study. Materials and Methods: This retrospective study included patients receiving at least three implants only. Patients presenting at least three implant failures were classified as presenting a cluster behavior. Univariate and multivariate logistic regression models and generalized estimating equations analysis evaluated the effect of explanatory variables on the cluster behavior. Results: There were 1406 patients with three or more implants (8337 implants, 592 failures). Sixty-seven (4.77%) patients presented cluster behavior, with 56.8% of all implant failures. The intake of antidepressants and bruxism were identified as potential negative factors exerting a statistically significant influence on a cluster behavior at the patient-level. The negative factors at the implant-level were turned implants, short implants, poor bone quality, age of the patient, the intake of medicaments to reduce the acid gastric production, smoking, and bruxism. Conclusions: A cluster pattern among patients with implant failure is highly probable. Factors of interest as predictors for implant failures could be a number of systemic and local factors, although a direct causal relationship cannot be ascertained.

Background: Implant fractures are rare but offer a challenging clinical situation. Purpose: To determine the prevalence of implant fracture and the possible risk factors predisposing an implant to a higher fracture risk. Materials and Methods: This retrospective study is based on 2670 patients consecutively treated with implant-supported prostheses. Anatomical-, patient-, and implant-related factors were collected. Descriptive statistics and survival analyses were performed. Generalized estimating equations (GEE) evaluated the effect of explanatory variables on implant fracture. Results: Forty-four implants (out of 10 099; 0.44%) fractured. The mean ± standard deviation time for fracture to occur was 95.1 ± 58.5 months (min-max, 3.8-294.7). Half of the occurrences of fracture happened between 2 and 8 years after implantation. Five factors had a statistically significant influence on the fracture of implants (increase/decrease in fracture probability): use of higher grades of titanium (decrease 72.9%), bruxism (increase 1819.5%), direct adjacency to cantilever (increase 247.6%), every 1 mm increase in implant length (increase 22.3%), every 1 mm increase in implant diameter (decrease 96.9%). Conclusions: It is suggested that 5 factors could influence the incidence of implant fractures: grade of titanium, implant diameter and length, cantilever, bruxism.

BACKGROUND: The oral rehabilitation with fixed restorations supported by the combination of teeth and dental implants has been advocated in some cases.

PURPOSE: To assess the clinical outcomes of these prostheses. Fixed restorations supported by the combination of teeth and dental implants.

MATERIALS AND METHODS: This retrospective study included all patients treated with combined tooth-implant-supported fixed dental prostheses (FDPs) at one specialist clinic. Abutment/prosthesis failure and technical complications were the outcomes analyzed.

RESULTS: A total of 85 patients with 96 prostheses were included, with a mean follow-up of 10.5 years. Twenty prostheses failed. The estimated cumulative survival rate was 90.7%, 84.8%, 69.9%, and 66.2% at 5, 10, 15, and 20 years, respectively. The failure of tooth and/or implant abutments in key positions affected the survival of the prostheses. There were seven reasons for prostheses failure, with the loss of abutments exerting a significant influence. Bruxism was possibly associated with failures. Prostheses with cantilevers did not show a statistically significant higher failure rate. No group had a general higher prevalence of technical complications in comparison to the other groups.

CONCLUSIONS: Although combined tooth-implant-supported FDPs are an alternative treatment option, this study has found that across 20 years of service nearly 35% the prostheses may fail.

BACKGROUND: Implant-supported fixed partial dentures (ISFPDs) are one of the most common options to rehabilitate partially edentulous patients.

PURPOSE: To assess the clinical outcomes of ISFPDs.

METHODS: This retrospective study included all patients treated with ISFPDs with 2 to 6 prosthetic units at one specialist clinic. Implant/prosthesis failure and technical complications were the outcomes analyzed.

RESULTS: Six hundred and forty-two patients with 876 ISFPDs (2241 implants) were included, followed up for 108.0 ± 76.2 months. Eighty-eight prostheses and 112 implants (26 before, 86 after prosthesis installation) failed. The estimated CSR of ISFPDs at 30 years was 72.7%. Smokers presented lower implant survival than nonsmokers. Two hundred and ninety-nine ISFPDs (33.2%) presented technical complications. Bruxism was a factor to exert a higher risk of screw and implant fracture, and ceramic chipping. ISFPDs with cantilever presented higher risk of failure, and screw loosening/fracture. Prostheses supported by implants with internal abutment connection or with two pontics had higher risk of presenting ceramic chipping. Extension of the prosthesis did not seem to exert influence on prosthesis failure/complications.

CONCLUSIONS: ISFPDs presented good long-term prognosis. Implant failure was the main reason for ISFPD failure. The results suggest that bruxism and the presence of cantilever may contribute to the increased rate of mechanical complications and prosthesis failure.

Background The association between IL-1 gene polymorphisms and peri-implantitis has been well documented. However, data on the association with early implant failure are scarce. Purpose The objective of this case-control study was to explore the impact of IL-1A (-889), IL-1B (-511), and IL-1B (+3,954) gene polymorphisms on early implant failure in Caucasians Materials and Methods Between September 2004 and August 2007, 461 patients were treated with dental implants at the University Hospital in Ghent, Belgium. Fourteen subjects of this patient group who had experienced one or more early implant failures (within 6 months from implant installation) were recruited as cases. Fourteen controls, matched in terms of age, gender, and smoking habits, with only surviving implants, were selected from the same patient group. Allele and genotype analysis was performed on the basis of a blood sample by Sanger sequencing of polymerase chain reaction products containing the IL-1A (-889), IL-1B (-511), and IL-1B (+3,954) gene polymorphisms Results A significant impact of the IL-1A (-889) T allele (p=.039) and the IL-1B (+3,954) T allele (p=.003) on early implant failure was demonstrated (odds ratios=3.9 and 15.0, respectively). In addition, the genotypic distribution differed significantly between cases and controls for IL-1B (+3,954) (p=.015 ConclusionsThe IL-1B (+3,954) gene polymorphism seems to affect osseointegration. Additional case-control studies in larger patient groups are needed to confirm this observation.

Purpose(1) To clinically evaluate horizontal remodeling of the alveolar process (hard and soft tissues) following ridge preservation in high-risk patients and (2) to identify predictors of such remodeling. Materials and MethodsPeriodontally healthy nonsmoking patients with a failing tooth in the anterior maxilla (15-25) were selected for a prospective case series. All were in need of a single implant and demonstrated high risk for aesthetic complications given an incomplete buccal bone wall and/or thin-scalloped gingival biotype. Following flapless tooth extraction, ridge preservation was performed using one or more collagen-enriched, bovine-derived block grafts (Geistlich Bio-Oss (R) Collagen (R) 100mg, Geistlich Pharma AG, Wolhusen, Switzerland) without the additional use of membranes or soft tissue grafts. The change in buccopalatal dimension of the alveolar process between baseline (prior to tooth extraction) and 4 months was assessed on the basis of superimposed occlusal slides. Regression analysis was performed to identify predictors of alveolar process remodeling ResultsForty-two patients (21 females, 21 males; mean age 38) met the selection criteria and consented to the treatment. Mean alveolar process remodeling was 14% (SD 7, range 4-30) with minimal remodeling (10%) in 16 patients (38%) and advanced remodeling (>20%) in 10 patients (24%). A single implant could be installed in all subjects without additional guided bone regeneration. Connective tissue grafting was performed later on in the treatment for aesthetic purposes, hereby compensating for tissue loss at the buccal aspect. Predictors of alveolar process remodeling were tooth location (central incisors and cuspids>laterals incisors and premolars), tooth abscess (p=.025), and buccal bone loss (p=.035 ConclusionAlveolar process remodeling seems inevitable yet acceptable following ridge preservation in high-risk patients. Proper case selection may reduce the incidence of advanced remodeling

ObjectiveTo evaluate the soft tissue response in humans immunologically and histologically after placement of mini-implants coated with or without nano-size hydroxyapatite coatings. Material and MethodsCommercially pure (cp) titanium mini-implants (n=13) or nano-hydroxyapatite-coated ones (n=12) were randomly placed into partially edentulous jaws. Crevicular fluid was sampled 1week after placement and subjected to quantitative polymerase chain reaction analysis to explore the inflammatory markers. After 8weeks, implants and surrounding soft and hard tissue were trephined, and undecalcified ground sections were prepared. Inflammatory cell accumulation within a defined region of interest in the soft tissue was quantified histomorphometrically. ResultsNo statistically significant differences in immunological response to the different implant surfaces were found for IL-6 (p=.438), TGF-2 (p=.467), MMP-8 (p=.758), CCL-3 (p=.758), IL-8 (p=.771), and IL-1 (0.771). Histomorphometric evaluation presented no statistically significant difference between the two mini-implant surfaces with regards to number of inflammatory cells (p=.669). ConclusionNano-hydroxyapatite-coated surfaces in the transmucosal region yielded similar inflammatory response and is suggested to be as biocompatible as commercially pure titanium surfaces.

Background:Histomorphometry and microcomputed tomography (microCT) have been used in implant studies but need better understanding before being used as equivalent methods. PurposeThe purpose of this study was to investigate the agreement between 2D (histomorphometry) and 3D (microCT) reference methods for assessing jawbone microarchitecture in vivo. Material and MethodsForty-four bone specimens from 32 patients were obtained during implant placement and examined by microCT, followed by hematoxylin-eosin staining and histomorphometric analysis. The morphometric parameters included bone volume density (BV/TV), bone surface fraction (BS/TV), bone surface density, trabecular thickness, trabecular number, and trabecular separation (Tb.Sp). Bland-Altman plots were used for pairwise agreement analysis between the equivalent 3D and 2D parameters, and complemented with Mountain plots. The association between the two methods was tested using Pearson's correlation followed by Passing-Bablok regression. ResultsSystematic bias was observed in all Bland-Altman and Mountain plots, including constant bias for BV/TV and Tb.Sp, and proportional bias for all other parameters. Significant correlation was found for BV/TV (r=0.80; p<.001) and BS/TV (r=0.44; p=.003), and the Passing-Bablok regression showed constant bias for BV/TV and proportional bias for BS/TV. ConclusionBecause of the poor agreement between measures obtained by histomorphometry and microCT, these methods should not be used interchangeably for jawbones.

Background Single implants were introduced in the 1980s, but long-term follow-up is scarce. Purpose The study aims to retrospectively investigate the prosthetic survival and complication rates of single implants in periodontally healthy patients after 16-22 years, and to evaluate the influence of different prosthetic procedures Materials and Methods Patients with a single implant were recalled for clinical examination. Prosthetic procedures included single-tooth (ST) and CeraOne (CO) abutments supporting a porcelain-fused-to-metal (PFM), all-ceramic (CER), or gold-acrylic (ACR) crown. Prosthetic survival, success, and occurrence of biological, technical, and aesthetic complications were obtained. Procedures were compared by log-rank tests Results Fifty patients attended the examination. All implants were functional; however, 15% of abutments and 27% of crowns had been renewed. Replacements (1/4) were related to technical issues whereas the main cause was aesthetics. The abutment cumulative survival rate (CSR) differed significantly between ST-PFM (74%), ST-ACR (0%), and CO reconstructions (97%). The crown CSR was significantly lower for ST-ACR crowns (0%) compared with ST-PFM (68%) and CO (81%). Thirty-nine percent of implants remained complication free throughout the mean 18.5 years. Complications (1/3) required component replacement, and 53% occurred within 5 years after surgery Conclusion Prosthetic survival rates of single implants are encouraging after 16 to 22 years. However, 66% of the patients encountered at least one complication during follow-up.

Publications from 2011 to 2015 were selected to evaluate effect of implant surface roughness on long-term bone loss as surrogate for peri-implantitis risk. 87 out of 2,566 papers reported the mean bone loss after at least 5 years of function. Estimation of the proportion of implants with bone loss above 1, 2, and 3 mm as well as analysis the effect of implant surface roughness, smoking, and history of periodontitis was performed. By means of the provided statistical information of bone loss (mean and standard deviation) the prevalence of implants with bone loss ranging from 1 to 3 mm was estimated. The bone loss was used as a surrogate parameter for peri-implantitis given the fact that peri-implantitis prevalence was not reported in most studies or when reported, the diagnostic criteria were unclear or of dubious quality. The outcome of this review suggests that peri-implant bone loss around minimally rough implant systems was statistically significant less in comparison to the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The studies that compared implants with comparable design and different surface roughness, showed less average peri-implant bone loss around the less rough surfaces in the meta-analysis. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems rather limited and of minimal clinical importance. Irrespective of surface topography or implant brand, the average weighted implant survival rate was 97.3% after 5 years or more of loading. If considering 3 mm bone loss after at least 5 years to represent the presence of peri-implantitis, less than 5% of the implants were affected. The meta-analysis indicated that periodontal history and smoking habits yielded more bone loss.

Background: Early loading of implant-supported prostheses in the edentulous mandible is widely accepted, but do the clinical results replicate those of delayed loading? Purpose: The aim of this study was to evaluate clinical outcome and patient satisfaction with early or delayed loading in patients treated with fixed prostheses, using three different implant systems. Materials and Methods: One hundred and nine consecutively treated patients received 490 implants supporting fixed prostheses; 82 patients with Brånemark System® implants (Nobel Biocare AB, Göteborg, Sweden), 16 with Astra Tech® implants (Astra Tech AB Dental Implant system, Mölndal, Sweden), and 11 with ITI® MonoType® implants (ITI Dental Implant System®, Institute Straumann AG, Waldenburg, Switzerland). Prostheses were placed within 2 to 3 weeks in 55 patients; 54 patients underwent a two-stage procedure. Data were collected from patient records and radiographs; 83 patients attended a clinical examination and received a questionnaire. Results: All patients had fixed prostheses at follow-up with a mean observation time of 3.5 years. Cumulative survival rates (CSRs) were 92.5% of prostheses and 94.4% of implants for early loading, and 98.0 and 97.9% for delayed loading. The mean radiographic bone loss after the first year was small, and at 5 years less than 0.2 mm for both groups. With early loading, significantly more prostheses (p < .05) needed adjustment or replacement. Conclusion: Statistically significantly more prostheses needed adjustment or replacement in the early group. The present study suggested lower CSRs for prostheses and implants in the early loading group after 5 years; the difference was not statistically significant. Larger study samples are needed to verify statistically small differences between treatment techniques.

BACKGROUND: New computer numeric controlled (CNC)-milled frameworks for implant-supported prostheses have been introduced. However, no data are available on the precision of fit of these new frameworks. PURPOSE: The purpose of this study is to evaluate the precision of fit of a new CNC-milled framework technique (I-Bridge, Biomain AB, Helsingborg, Sweden) using Brånemark System (Nobel Biocare AB, Göteborg, Sweden) and NobelReplace (Nobel Biocare AB) system implants. MATERIALS AND METHODS: Ten test frameworks were fabricated for one master model for each implant system. Five additional frameworks were fabricated for five different models simulating clinical cases as controls (Brånemark System). The distortion of implant center point positions was measured in x-, y-, and z-axes and in three dimensions by using a contact-type coordinate measuring machine and a computer program developed specifically for this purpose. Mann-Whitney U-test was used to compare differences of distortion within and between the groups. RESULTS: The maximal distortion in arch width (x-axis) and curvature (y-axis) was within 71 and 55 microm for all frameworks, respectively. The mean distortion in absolute figures in x-, y-, z-axes and three dimensions was for "clinical control" frameworks 23, 26, 4, and 34 microm as compared with less than 12, 12, 2, and 17 microm for Brånemark and NobelReplace frameworks, respectively. Control frameworks showed significantly (p < .05) greater mean and range of distortions in x- and y-axes and in three dimensions compared with test frameworks. CONCLUSION: All measured frameworks presented signs of misfit, indicating that no framework had a "passive fit." Frameworks produced in a more routine clinical environment seem to present greater levels of distortion as compared with frameworks produced in a strict test situation. However, all measured frameworks presented levels of precision of fit within limits considered to be clinically acceptable in earlier studies of frameworks placed on abutments.

PURPOSE: The aim of the present study was to compare the treatment outcome of TiUnite- and turned-surfaced Branemark System (Nobel Biocare AB, Goteborg, Sweden) implants when applying immediate loading of cross-arch designed fixed partial dentures in the anterior mandible. MATERIALS AND METHODS: Fifteen patients with edentulous mandibles participated in the study. In one half of the jaw, between the exit of the nerve-vessel bundle and the midline, one type of implant was placed and in the remaining half the other type. The implants were loaded the day of surgery via a fixed, temporary supra-construction. Ten days later, the permanent one was screw retained to the implant pillars. RESULTS: The present 18-month clinical trial failed to demonstrate any differences regarding healing and cumulative success rate of an an-oxidized implant surface (TiUnite) and a turned (turned) one when implants in the anterior mandible were exposed to functional load within 24 hours after installation. CONCLUSION: A high predictability regarding the treatment outcome for immediately loaded Branemark implants in the anterior mandible was observed. Furthermore, no difference between the traditional turned and the an-oxidized implant surface (TiUnite) could be observed. However, it has to be stressed that all implants (irrespective of surface) were placed in the anterior mandible and also that all the patients demonstrated a high level of oral hygiene.

BACKGROUND: Incorporation of Ca(2+) into the titania of anodized titanium surfaces has been found to enhance osseointegration. It provides a stable surface when the ions are incorporated into the oxide layer during the anodizing process. The Ca(2+) may suggestively be prominent sites for mineral induction, attract proteins, and catalyze intracellular cascades. PURPOSE: The aim of the present study was to evaluate the osseointegration of smooth (S(a) < 0.5 µm) and moderately rough (S(a) 1.0-2.0 µm) commercially pure titanium implants, with and without Ca(2+) , in order to reflect on the importance of surface chemistry in relation to topography. MATERIALS AND METHODS: Anodized implants with (OxCa) or without Ca(2+) (Ox), blasted implants (Bl), and blasted anodized implants, with (BlOxCa) or without Ca(2+) (BlOx), were inserted in rabbit femur and tibia. The implant surfaces were characterized using interferometry, scanning electron microscopy, and X-ray photoelectron spectroscopy prior to implant installation. Removal torque (RTQ) measurements were executed on all implants after a healing period of 12 weeks. The implants were, thereafter, removed en bloc with surrounding tissues and prepared for histological evaluations. RESULTS: RTQ measurements of tibial implants revealed significantly higher values for BlOxCa implants (90.7 ± 23.3 Ncm) compared to OxCa (64.6 ± 18.2 Ncm) and BlOx implants (69.7 ± 17.5 Ncm) (p = 0.029). Ca(2+) modification of smooth implants placed in the femur did not reveal any differences. CONCLUSION: Ca(2+) modification of smooth implants resulted in similar interfacial shear strength as moderately rough implants and Ca(2+) modification of moderately rough implants demonstrated the significantly strongest interfacial shear strength when placed in rabbit tibia. This possibly demonstrated surface chemistry compensating for lesser roughness.

Background: Mesoporous coatings enable incorporation of functional substances and sustainedly release them at the implant site. One bioactive substance that can be incorporated in mesoporous is magnesium, which is strongly involved in bone metabolism and in osteoblast interaction. Purpose: The aim of this experimental study was to evaluate the effect of incorporation of magnesium into mesoporous coatings of oral implants on early stages of osseointegration. Material and Methods: Titanium implants were coated with thin films of mesoporous TiO2 having pore diameters of 6 nm and were loaded with magnesium. The implant surfaces were extensively characterized by means of interferometry, atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy and then placed in the tibiae of 10 rabbits. After 3 weeks of healing, osseointegration was evaluated by means of removal torque testing and histology and histomorphometry. Results: Histological and biomechanical analyses revealed no side effects and successful osseointegration of the implants. The biomechanical evaluation evidenced a significant effect of magnesium doping on strengthening the implant-bone interface. Conclusions: A local release of magnesium from the implant surfaces enhances implant retention at the early stage of healing (3 weeks after implantation), which is highly desirable for early loading of the implant.

Background: Immediate loading of single implants is generally considered a reliable procedure. Purpose: The objective of the present prospective randomized clinical study was to compare the overall treatment outcome following immediate loading (IL) and delayed loading (DL) of single implants after 1 year of follow-up. Materials and Methods: Patients with a missing maxillary tooth (15-25) were randomly assigned to IL or DL. The protocol included implant installation in healed sites, immediate loading, delayed loading, temporary screw-retained restoration, and replacement with a permanent single implant crown. Outcome measures were implant survival, marginal bone level, soft tissue changes, papillae index, pink, and white esthetic score (PES and WES), patient judged aesthetics, and oral health impact profile (OHiP-14). Results: Implant survival rate was 100% and 96% for IL and DL, respectively. Implant success rate was 96% and 88% for IL and DL, respectively. Statistically significant lower papilla index scores were found in the IL group at temporary crown and definitive crown placement. An overall statistically significant improvement after 12 months for PES, WES and OHIP-14 was found. Conclusion: This prospective randomized study showed that single implants in the maxilla can present satisfactory results with respect to either immediate loading or delayed loading after 12 months.

Background Developments in implant hardware and biologic understanding improved treatment predictability in terms of implant survival. Current research focuses on accelerated loading protocols and crestal bone preservation. Purpose This prospective, monocenter study analyzed the clinical and radiographic outcome of a novel parallel-walled implant, with and without platform shift Materials and Methods Forty-eight consecutively treated patients (30 women, 18 men) with crowns/bridges supported by 115 implants were included. Eighty-three percent of implants were nonocclusal, immediately loaded, and 17% were subjected to one-stage surgery and delayed loading after 10 weeks; 39.1% were of diameter 5.0mm, enabling platform shifting with a 4.0mm-wide prosthetic component; 60.9% were of diameter 4.0mm with a 4.0mm component. Radiographic crestal bone levels were assessed at baseline and 1 year. A multivariate statistical analysis was performed to determine factors affecting crestal bone loss after 1 year Results All implants survived and mean marginal bone loss was 0.73mm (SD: 0.13; range: -0.60 to 5.0mm). There was a statistically significant difference between platform-shifted (0.63mm; SD: 0.18) and nonplatform-shifted (1.02mm; SD: 0.14) implants. Implants in abundant bone volume lost significant less crestal bone (0.45mm; SD: 0.14) compared with implants in small volume (1.20mm; SD: 0.21). Implant diameter, loading time, anatomical position, smoking, and bone quality did not affect crestal bone loss Conclusion After 1 year of loading, both implant-prosthetic features yield a high survival and limited crestal bone loss. Crestal bone loss is minimized using platform-shifted implants placed in sufficiently voluminous bone. To limit the crestal bone loss, an adopted implant diameter with platform shifting should be considered.

Background: Cell interactions, adherence, and osseointegration at the bone-implant interface can be directly influenced by the surface properties of the titanium implant. Purpose: To characterize osseointegration of Neoss (R) implants with conventional (control group) and hydrophilic (test group) surface treatments. Materials and Methods: Six Labrador dogs received Neoss implants with conventional and hydrophilic surfaces. The bone-implant interfaces were evaluated 1 and 4 weeks after implantation, and osseointegration was evaluated using histological, histomorphometric, fluorescence, and resonance frequency analyses. The surfaces were also subjected to topographic and hydrophilicity analyses. Results: The topographic analyses revealed increased surface roughness in the test group compared with the control group (surface area roughness 0.42 and 0.78 mu m, respectively, for control and test group surfaces; p <= .05). The wettability values were higher in the test group (contact angles 67.2 degrees and 27.2 degrees for the control and test group surfaces, respectively; p <= .05). Implants in the test group also exhibited better stability, more bone-implant contact, and increased bone area compared with implants in the control group. Conclusion: Neoss implants in the test group improved bone formation in the early stages of osseointegration compared with implants in the control group.

Background: A newly developed, anodized titanium oxide surface containing anatase has been reported to have antimicrobial properties that could reduce bacterial adherence to abutments. Purpose: To investigate if abutments with the anodized surface improve healing and soft tissue health in a randomized controlled study. Materials and Methods: Test abutments with a nanostructured anodized surface were compared with control machined titanium abutments. In total, 35 subjects each received a pair of test and control abutments. The primary endpoint was reduction of biofilm formation at test abutments at the 6‐week follow‐up. Secondary endpoints included several soft tissue assessments. qPCR for gene markers was used to indirectly evaluate healing and soft tissue health. Results: No significant differences in biofilm formation were observed between test and control abutments, but soft tissue bleeding upon abutment removal was significantly lower for test abutments compared with control abutments (P = 0.006) at 6 weeks. Keratinized mucosa height was significantly greater at test abutments compared with control abutments at the 6‐week, 6‐month, and 2‐year follow‐ups. Significant gene expression differences indicated differences in healing and tissue remodeling. Conclusions: Abutments with an anodized and nanostructured surface compared with a conventional, machined titanium surface had no significant effect on bacterial colonization and proteolytic activity but were associated with better soft tissue outcomes such as a lower bleeding index at abutment removal and consistently greater height of keratinized mucosa throughout the 2‐year follow‐up, suggesting improved surface‐dependent peri‐implant healing and soft tissue health.

Objective Bone is constantly exposed to dynamic and static loads, which induce both dynamic and static bone strains. Although numerous studies exist on the effect of dynamic strain on implant stability and bone remodeling, the effect of static strain needs further investigation. Therefore, the effect of two different static bone strain levels on implant stability and bone remodeling at two different implantation times was investigated in a rabbit model. Methods Two different test implants with a diametrical expansion of 0.15 mm (group A) and 0.05 mm (group B) creating initial static bone strains of 0.045 and 0.015, respectively. The implants were inserted in the proximal tibial metaphysis of 24 rabbits to observe the biological response at implant removal. Both groups were compared to control implants (group C), with no diametrical increase. The insertion torque (ITQ) was measured to represent the initial stability and the removal torque (RTQ) was measured to analyze the effect that static strain had on implant stability and bone remodeling after 3 and 13 days of implantation time. Results The ITQ and the RTQ values for test implants were significantly higher for both implantation times compared to control implants. A selection of histology samples was prepared to measure bone to implant contact (BIC). There was a tendency that the BIC values for test implants were higher compared to control implants. Conclusion These findings suggest that increased static bone strain creates higher implant stability at the time of insertion, and this increased stability is maintained throughout the observed period.

BACKGROUND: Implant failure and biologic complications such as periimplantitis are not completely avoidable. Are there any genetic and microbiologic parameters that could be used to identify patients at risk for implant failure, preferably prior to treatment? This would result in improvement of the diagnostics, treatment decision, and risk assessment. PURPOSE: The aims of this retrospective study were to describe (1) the absolute failure rate of Branemark System implants (Nobel Biocare AB, Goteborg, Sweden) consecutively installed over a 10-year period in partially edentulous patients treated for periodontal disease prior to implant treatment and under regular professional maintenance, (2) the rate of interleukin-1 (IL-1) polymorphism in those patients who experienced at least one implant failure during the first year of function, and (3) the prevalence of periodontal pathogens in dental and periimplant sites with and without signs of inflammation. MATERIAL AND METHODS: Of 766 patients, 81 encountered at least one implant failure; 22 patients were clinically examined and were tested genetically for IL-1 genotypes. The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella ni-grescens was analyzed. RESULTS: The absolute implant survival rate for the whole population was 95.32%; 10.57% of the patients encountered an implant loss. Implant loss in the examined group (n = 22) was 32 of 106 (30.1%); 10 (45%) of the 22 patients were smokers, and 6 (27%) of the 22 patients were IL-1 genotype positive. Patients positive for IL-1 genotype were not more prone to implant loss; however, a significant synergistic effect with smoking was demon-strated. Between patients who were IL-1 genotype positive and those who were IL-1 genotype negative, the differences in regard to bleeding on probing or periodontal pathogens did not reach statistical significance. CONCLUSION: The overall implant failure rate in a population treated and maintained for periodontal disease is similar to that of healthy subjects. A synergistic effect found between smoking and a positive IL-1 genotype resulted in a significantly higher implant loss. This indicates that further research with a larger patient group should focus on multifactorial analysis for adequate risk assessment.

BACKGROUND: Clinically, there is a demand for mechanically stronger alloyed implants; however, not much evidence exists with regard to these materials. PURPOSE: To test the osseointegration property of TiZr1317 implants in a rabbit model. MATERIALS AND METHODS: Hydrophilic titanium-zirconium alloy (TiZr1317) implants with sand-blasted and acid-etched surface (test) and hydrophilic cpTi implants with the same treatment (control) were placed pairwise in the hind limbs (two in each tibia and one in each femur) of 36 Swedish lop-eared rabbits. After 2, 4, and 12 weeks (n = 12/time point), the bone samples were subjected to removal torque (RTQ, proximal tibia and femur) and histologic/histomorphometric (distal tibia) testings. RESULTS: The control presented significantly higher RTQ than the test at 2 weeks (55 vs 36 Ncm). No differences were observed for other time points. The test presented higher mean BIC than the control (19.25 vs 13.89 %) at 4 weeks; however, there were no statistical differences for the following time point tested in vivo.The new bone area was significantly higher for the test at 4 weeks in the marrow areas. CONCLUSION: The TiZr1317 implants presented comparable biologic outcomes to that of the cpTi implants through a 12-week evaluation period.

BACKGROUND: In the previous in vitro study, fluoride-modified, anodized porous titanium was proven to have enhanced its photo-induced hydrophilicity, which induced the hyperactivation of initial cell response. PURPOSE: The purpose of the present study was to investigate in vivo bone apposition during the early stages of osseointegration in rabbit tibiae. MATERIALS AND METHODS: Anodized porous titanium implants (TiU, TiUnite®, Nobel Biocare AB, Göteborg, Sweden) were modified with 0.175 wt% ammonium hydrogen fluoride solution (NH(4) F-HF(2) ). Twenty-four hours prior to the experiments, the surface-modified implants were ultraviolet-irradiated (modTiU). Blinded and unpackaged TiU implants were used as controls. Thereafter, the implants were placed in the rabbit tibial metaphyses and histomorphometrically analyzed at 2 and 6 weeks after insertion. RESULTS: ModTiU demonstrated a significantly greater degree of bone-to-metal contact than TiU after 2 and 6 weeks of healing. CONCLUSION: The results proved that the enhanced photo-induced hydrophilicity of the NH(4) F-HF(2) -modified anodized implants promoted bone apposition during the early stages of osseointegration.

ABSTRACT Objective: The removal torque (RTQ) analysis is commonly used for biomechanical evaluation of osseointegration. The overall aim of this study was to verify results obtained with a newly developed equipment for biomechanical testing of osseointegration. Methods: Verification of the new equipment for biomechanical tests involved three experiments: Part I, comparison of RTQ between implants placed in four different types of dental synthetic plasters. Part II, comparison of RTQ between custom made, experimentally used implants to self-tapping, commercially available implants molded in the same type of dental plaster. Part III, comparison of RTQ between commercially pure titanium implants to Ti6Al4V implants placed in rabbit bone, 6 weeks after insertion. Briefly, for all experiments, the peak RTQ values and the removal process were recorded every 0.01 seconds up to 10 seconds. After the measurements, peak RTQ values were converted to shear strength. Results: The developed equipment sensitively responded to the changes of properties related to the molding plasters, implant topographies, and materials. The monitored graphs corresponded well to the expected properties of the different implants and tested materials. Conclusion: The new RTQ equipment proved to be accurate and could add new knowledge in understanding the biomechanical aspects of osseointegration.

Background: The mere lifting of the maxillary sinus membrane by implants protruding into the sinus cavity allows the establishment of a void space for blood clot and new bone formation. Purpose: To evaluate bone formation by using a spherical, hollow, and perforated hydroxyapatite space-maintaining device (HSMD) in a two-stage sinus lift procedure where residual alveolar bone height was

PURPOSE: To evaluate and compare outcome among patients after implant overdenture treatment in the maxilla. MATERIALS AND METHODS: The study sample comprised two groups of patients: group 1, in which the patients were planned for overdenture treatment, and group 2, in which the patients originally were planned for a fixed prosthesis in the maxilla but had overdenture treatment owing to implant failures, resulting in an insufficient number of implants to support a fixed prosthesis. All patients treated with maxillary implant-supported overdentures in the Department of Prosthetic Dentistry, Central Hospital, Skovde, Sweden, between 1993 and 2002 received a questionnaire at their yearly follow-up visit with nine questions related to their treatment. All questions had visual analogue scale response alternatives ranging from a negative to a positive opinion. RESULTS: Nineteen patients, 10 in group 1 and 9 in group 2, completed the questionnaire, yielding a response rate of 86%. Both groups expressed a high satisfaction rate, and few regretted their choice of treatment. Patients planned for overdenture treatment (group 1) reported significantly fewer speech problems after treatment compared with those originally planned for a fixed prosthesis (group 2, p < .05). No other significant differences between the two groups were seen. CONCLUSION: Within the limitations of the present study, it can be concluded that maxillary implant overdenture treatment may be considered a viable option among patients with an insufficient number of implants for a fixed prosthesis

BackgroundWound healing events after implant placement will vary according to the extent of the necrotic zone. PurposeThe goal of the present study was to evaluate bone healing around titanium implants with a novel apical chamber design. Materials and MethodsTitanium implants grade 4 were turned with different apex design. Control implants had a self tapping design with centric cutting grooves. Test implants exhibited eccentric cutting grooves interconnected by a hollow chamber. A total of 60 implants were installed in the femur/tibia of 10 rabbits for histological analysis. ResultsAfter 1 week, immature bone formation started at the cortical level of the test implants associated to scalloped contours indicative of bone resorption. Control implants failed to show new bone formation, and the space within the threads was filled mainly by red blood cells and surgical debris. Bone contact values showed no difference after 1 week, and significant higher values for test implants showed likewise after 4 weeks compared with control implants in the tibia. ConclusionThis experimental study verifies the beneficial effect of bone formation in the chamber at the apical part of the fixture coupled to a faster bone healing to implants placed in dense bone.

PURPOSE: Hydroxyapatite (HA) or titania nanostructures were applied on smooth titanium implant cylinders. The aim was to investigate whether nano-HA may result in enhanced osseointegration compared to nano-titania structures. MATERIALS AND METHODS: Surface topography evaluation included detailed characterization of nano-size structures present at the implant surface combined with surface roughness parameters at the micro- and nanometer level of resolution. Microstructures were removed from the surface to ensure that bone response observed was dependent only on the nanotopography and/or chemistry of the surface. Early in vivo histological analyses of the bone response (4 weeks) were investigated in a rabbit model. RESULTS: In the present study, nano-titania-coated implants showed an increased coverage area and feature density, forming a homogenous layer compared to nano-HA implants. Bone contact values of the nano-titania implants showed a tendency to have a higher percentage as compared to the nano-HA implants (p = .1). CONCLUSION: Thus, no evidence of enhanced bone formation to nano-HA-modified implants was observed compared to nano-titania-modified implants. The presence of specific nanostructures dependent on the surface modification exhibiting different size and distribution did modulate in vivo bone response.

Background The growing resistance of bacteria to antimicrobial medicines is a global issue and a direct threat to human health. Despite this, antibiotic prophylaxis is often still routinely used in dental implant surgery to prevent bacterial infection and early implant failure, despite unclear benefits. There is a lack of sufficient evidence to formulate clear clinical guidelines and therefore there is a need for well-designed, large-scale randomized controlled trials to determine the effect of antibiotic prophylaxis. Purpose To compare the effect of a presurgical antibiotic regimen with an identical placebo regimen in healthy or relatively healthy patients receiving dental implants. Materials and Methods The 474 patients participating in the study were recruited from seven clinics in southern Sweden. We randomized the patients into a test and a placebo group; the study was conducted double-blinded. Preoperatively, the test group received 2 g of amoxicillin and the control group, identical placebo tablets. The primary outcome was implant failure; secondary outcomes were postoperative infections and adverse events. Patients were evaluated at two follow-ups: at 7-14 days and at 3-6 months. Results Postoperative evaluations of the antibiotic (n = 238) and the placebo (n = 235) groups noted implant failures (antibiotic group: six patients, 2.5% and placebo group: seven patients, 3.0%) and postoperative infections (antibiotic group: two patients, 0.8% and placebo group: five patients, 2.1%). No patient reported any adverse events. Between-group differences in implant failures and postoperative infections were nonsignificant. Conclusion Antibiotic prophylaxis in conjunction with implant placement is likely of small benefit and should thus be avoided in most cases, especially given the unabated growth in antibiotic-resistant bacteria. Clinical trial registration number: NCT03412305.

BACKGROUND: There is a need for prospective, long-term follow-up studies of implants placed after maxillary sinus floor augmentation (MSFA).

PURPOSE: The aim of the present study was to determine whether deprotenized bovine bone (DPBB) used for MSFA may result in long-term stability of placed dental implants.

MATERIAL AND METHODS: Fourteen of the 20 patients included in the study were followed throughout the 10 years study period. These patients had 53 implants placed in 22 (6 unilateral and 8 bilateral) maxillary sinuses augmented with a mixture of 80% DPBB and 20% autogenous bone (80:20), and 15 implants placed in non-grafted sites. Clinical and radiographic examinations of the implants and grafts were performed.

RESULTS: After 10 years of functional loading 15 of the initially placed 108 implants had been lost giving a cumulative survival rate of 86%. The mean marginal bone loss was 1.6 ± 1.0 mm. There were no statistically significant differences in marginal bone level, pocket depth, or ISQ-values between implants placed in residual or grafted bone or between smokers or non-smokers at 10 years follow-up. There was a statistically significant reduction (p < .01) in graft height between 3 months and 2 years but no further significant reduction up to 10 years.

CONCLUSIONS: The first 2 years after placement of implants with turned surfaces placed in sites after sinus floor augmentation with DPBB and autogenous bone seem to be critical for implant survival. At 10 years follow-up, the remaining implants presented excellent clinical and radiological results regardless of smoking habits or implant sites (augmented or residual bone).

Purpose: To evaluate of the effect of self-cutting and nonself-cutting thread designed implant with different thread depth on variable insertion torques. To evaluate the bone volume (BV) and bone to implant contact (BIC) in these variables Materials and Methods: Mainly two thread design, V-shaped thread which is self-cutting and power thread design, which is nonself-cutting implants were considered for this study with a variation in thread depth of 0.4 and 0.6 mm for both the designs, respectively. A total of 32 CAD designed machined surface implant prototypes were manufactured of 4 mm in diameter and 8 mm in length were made, which were machined surfaced, which was placed in the femur of 16 New Zealand white rabbits. These were categorized under 2 groups; Group 1 and Group 2 with insertion torques of <30 and >50 Ncm, respectively. After 4 weeks of healing, rabbits were sacrificed and histomophometric and histologic analyses were done to evaluate the bone response. Results: Significantly, more BIC was recorded for high torque implants compared with low torque in power-shaped thread design (P value5.01*). BV for new bone formation was statistically significant for V-shaped thread design in high torque when compared with low torque (P value5.02*). Conclusion: The effect of the depth of the thread design was significant for the power-shaped design in enhancing BIC when compared with V-shaped thread design. With high torque V-shaped thread design had more new bone formation as compared with power-shaped thread design.

Background: Studies have reported an increased risk for fractures of zirconia abutments compared with titanium abutments. Purpose: The aim of this study was to evaluate single-tooth implant restorations with one-piece yttria-stabilized internal zirconia abutments on narrow and regular diameter implants up to 6 years after insertion. Material and methods: This study comprises 52 consecutively treated patients, with a median age of 19 years. In total, 59 narrow (3.3 mm) and 10 regular (4.1 mm) diameter implants were installed. Sixty-five all-ceramic crowns were cemented on implant-supported one-piece internal zirconia abutments and 4 restorations were screw-retained. Results: Thirty-five patients with 48 implant restorations participated in the final examination and another 14 patients with 16 implant restorations were possible to reach and could be interviewed. The implant survival was 100% but the survival rate for the implant-supported ceramic restorations was lower, 87.5%. Three crowns (4.7%) were remade for different reasons. Five restorations (7.8%) were remade due to fracture of the internal one-piece zirconia abutment. Four of these fractures occurred in 3.3 mm implant abutments. Conclusions: Narrow diameter implants offer an opportunity to restore small single-tooth edentulous gaps. For esthetical reasons the choice of an abutment in zirconia can be favorable, but at least with the used implant system, there seems to be an increased risk for fracture. Most patients were very satisfied with the esthetics and function of their implant restorations.

Background In the maxillary incisor area infraposition of implant restorations can be an esthetic problem. Purpose The aim was to analyze the prevalence of infraposition of single-tooth implant restorations in the anterior maxilla in adolescent and adult patients. Material and Methods The study comprised of 31 patients, 18 women and 13 men, with 39 restorations and with a mean and median age of 23.8 and 18.8 years, range 17.8 to 52.8 years, at the time of implant crown connection. The mean and median time in function for the restorations was 4.5 and 4.3 years respectively with a range of 3.3 to 6.6 years. Results Twenty restorations 51%, showed no signs of infraposition. A slight infraposition (<0.5 mm) was seen in 36% of the restorations. Only in one patient, the observed infraposition of the implant crown was more than 1 mm. We found no significant difference of the observed level of vertical infraposition, Score A (0 mm) and Score B (<0.5 mm), in subjects where the restoration was placed before the age of 20 years compared to the older patients. There were no significant differences in changes of the vertical infraposition when comparing different parameters such as age, gender, jaw relation (Angle-classes I-III), overbite/overjet, occlusal contact on the implant crown, bone augmentation before or at implant installation or if orthodontic treatment of the neighboring teeth had been made before or after the implant installation. Conclusions In the present study, there was a significant yet low correlation between the observed vertical infraposition of the single-tooth implant restoration and the subject's evaluation of the esthetics of the restoration (VAS). Fifty-one percent of the implant-supported crowns, showed no signs of vertical infraposition. A slight infraposition (< 0.5 mm) was however seen in 36% of the restorations. Only one crown showed a vertical infraposition of more than 1 mm.