The role of autophagy in the process of osseointegration around titanium implants with micro-nano topography promoted by osteoimmunity.

Osteoimmunity plays an important role in the process of implant osseointegration. Autophagy is a conservative metabolic pathway of eukaryotic cells, but whether the interaction between autophagy and osteoimmunity plays a key role in osseointegration remains unclear. In this study, we prepared smooth titanium disks and micro-nano topography titanium disks, to study the immune microenvironment of RAW264.7 cells, and prepared the conditioned medium to study the effect of immune microenvironment on the osteogenesis and autophagy of MC3T3-E1 cells. Autophagy inhibitor 3-MA was used to inhibit autophagy to observe the change of expression of osteogenic markers. The results showed that the micro-nano topography titanium disks could stimulate RAW264.7 cells to differentiate into M2 type, forming an anti-inflammatory immune microenvironment; compared with the control group, the anti-inflammatory immune microenvironment promoted the proliferation and differentiation of osteoblasts better. The anti-inflammatory immune environment activated the autophagy level of osteoblasts, while the expression of osteogenic markers was down-regulated after inhibition of autophagy. These results indicate that anti-inflammatory immune microenvironment can promote cell proliferation and osteogenic differentiation, autophagy plays an important role in this process. This study further explains the mechanism of implant osseointegration in osteoimmune microenvironment, and provides reference for improving implant osseointegration.

Physiology of Osseointegration.

"Bone conduction implant devices rely on osseointegration of titanium implants with the underlying skull, characterized by endosseous healing and de-novo bone formation both surrounding and onto the implant surface. The key steps in osseointegration are the initial tissue response to implantation, peri-implant osteogenesis, and peri-implant bone remodeling. There is increasing evidence that osseointegration is primarily an immune-mediated process with the key players being the complement cascade and macrophages, which form part of the host innate immunity. Implant design and composition, patient systemic factors, surgical technique, and loading characteristics can all affect the success of osseointegration."

Efeito modulador da radiação ionizante sobre citocinas sanguíneas e células do tecido ósseo na interface osso-implante / Modulating effect of ionizing radiation on blood cytokines and bone tissue cells at the bone-implant interface

Implantes osseointegrados são considerados efetivos como tratamento reabilitador. Contudo, vários fatores podem prejudicar o sítio receptor, entre eles, a radiação ionizante. Entretanto, os mecanismos pelos quais estes eventos acontecem ainda não foram completamente esclarecidos. O objetivo neste estudo foi avaliar o efeito modulador da radioção ionizante, simulando uma dose total de um tratamento radioterápico convencional para pacientes oncológicos, nos níveis de citocinas sanguíneas e na remodelação óssea da interface ao redor do implante. Foram utilizados 45 ratos que receberam implantes rosqueados de titânio grau V nos fêmures direito. Os animais foram divididos em 3 grupos: a) Grupo Sem-Irradiação (S-Ir): grupo controle apenas com implante. b) Grupo Irradiação Posterior (IrPos): implante + irradiação; c) Grupo Irradiação Prévia (IrPrev): irradiação + implante. Os animais dos grupos IrPos e IrPrev foram submetidos a irradiação em 2 etapas fracionadas de 15 Gy. Nos períodos de 3 dias, 2 semanas e 7 semanas após o último procedimento, 05 animais foram eutanasiados aleatoriamente por grupo. Os níveis séricos de TNF-ɑ, IL-1ß e IL-10 foram mensurados a partir do sangue coletado previamente ao momento da eutanásia pelo método imunoenzimático (ELISA). As peças contendo os implantes foram submetidos à marcação imunohistoquímica utilizando os marcadores para TRAP e osteocalcina (OC). O teste ANOVA foi utilizado para análise estatística e quando necessário foi aplicado o teste de comparação múltipla de Tukey (p<0,05). O grupo IrPos exibiu diferença estatística (p<0,05) com S-Ir e IrPrev nos valores de TNF-α em 2 e 7 semanas, enquanto IrPrev diferiu estatisticamente (p<0,05) de S-Ir nos valores de IL-10, em 3 dias. A análise imuno-histoquímica da interface osso-implante, demonstrou valores mais altos de TRAP e OC nos grupos irradiados, com diferença estatística (p<0,05), entre os valores de TRAP de S-Ir e IrPos em 3 dias e entre S-Ir e IrPrev em todos os períodos, e de OC entre S-Ir e IrPos em 3 dias e entre S-Ir e IrPrev em 2 semanas. Em suma, os resultados desse estudo indicaram que a radiação ionizante alterou produções de citocinas sanguíneas pró e anti-inflamatórias após lesão cirúrgica de colocação do implante e influenciou na expressão de proteínas envolvidas na remodelação óssea(AU)

Osseointegrated implants are considered effective as a rehabilitative treatment. However, several factors may impair the receptor site, including ionizing radiation. However, the mechanisms by which these events occur have not yet been fully elucidated. The objective of this study was to evaluate the modulating effect of radiotherapy, simulating a total dose of a conventional ionizing radiation treatment for cancer patients, blood cytokine levels and bone remodeling of the interface around the implant. Forty-five rats were submitted to grade V titanium implants in the right femurs. The animals were divided into three groups: a)No Irradiation group (N-Ir): control group with only the implant b) Previous irradiation group (Prev-Ir): implant + irradiation; c) Posterior Irradiation group (Pos-Ir): irradiation + implant. Pos-Ir and Prev-Ir groups were irradiated in 2 fractional stages of 15 Gy. At 3 days, 2 weeks and 7 weeks after the last procedure, 05 animals were randomly euthanized per group. Serum levels of TNF-ɑ, IL-1ß and IL-10 were measured from blood collected prior to euthanasia using the enzyme-linked immunosorbent assay (ELISA). The pieces containing the implants were subjected to immunohistochemical labeling using the markers for TRAP and osteocalcin (OC). The ANOVA test was used for statistical analysis and when necessary the Tukey multiple comparison test (p <0.05) was applied. The Pos-Ir group exhibited a statistical difference (p <0.05) with N-Ir and Prev-Ir in TNF-α values at 2 and 7 weeks, whereas Prev-Ir differed statistically (p <0.05) from N-Ir in IL-10 values, in 3 days. The immunohistochemical analysis of the bone-implant interface demonstrated higher values of TRAP and OC in the irradiated groups, with a statistical difference (p <0.05) between the values of TRAP of N-Ir and Pos-Ir in 3 days and between N-Ir and Prev-Ir in all periods, and OC between N-Ir and Pos-Ir in 3 days and between N-Ir and Prev-Ir in 2 weeks. In summary, the results of this study indicated that irradiation altered productions of pro and antiinflammatory blood cytokines after surgical lesion of implant placement and influenced the expression of proteins involved in bone remodeling(AU)

OsteoMacs: Key players around bone biomaterials.

Osteal macrophages (OsteoMacs) are a special subtype of macrophage residing in bony tissues. Interesting findings from basic research have pointed to their vast and substantial roles in bone biology by demonstrating their key function in bone formation and remodeling. Despite these essential findings, much less information is available concerning their response to a variety of biomaterials used for bone regeneration with the majority of investigation primarily focused on their role during the foreign body reaction. With respect to biomaterials, it is well known that cells derived from the monocyte/macrophage lineage are one of the first cell types in contact with implanted biomaterials. Here they demonstrate extremely plastic phenotypes with the ability to differentiate towards classical M1 or M2 macrophages, or subsequently fuse into osteoclasts or multinucleated giant cells (MNGCs). These MNGCs have previously been characterized as foreign body giant cells and associated with biomaterial rejection, however more recently their phenotypes have been implicated with wound healing and tissue regeneration by studies demonstrating their expression of key M2 markers around biomaterials. With such contrasting hypotheses, it becomes essential to better understand their roles to improve the development of osteo-compatible and osteo-promotive biomaterials. This review article expresses the necessity to further study OsteoMacs and MNGCs to understand their function in bone biomaterial tissue integration including dental/orthopedic implants and bone grafting materials.

Foreign Body Reaction to Biomaterials: On Mechanisms for Buildup and Breakdown of Osseointegration.

BACKGROUND: The last few decades have seen a progressive shift in paradigm, replacing the notion of body implants as inert biomaterials for that of immune-modulating interactions with the host. PURPOSE: This text represents an attempt at understanding the current knowledge on the healing mechanisms controlling implant-host interactions, thus interpreting osseointegration and the peri-implant bone loss phenomena also from an immunological point of view. MATERIALS AND METHODS: A narrative review approach was taken in the development of this article. RESULTS: Osseointegration, actually representing a foreign body reaction (FBR) to biomaterials, is an immune-modulated, multifactorial, and complex healing process where a number of cells and mediators are involved. The buildup of osseointegration seems to be an immunologically and inflammatory-driven process, with the ultimate end to shield off the foreign material placed in the body, triggered by surface protein adsorption, complement activation, and buildup of a fibrin matrix, followed by recruitment of granulocytes, mesenchymal stem cells, and monocytes/macrophages, with the latter largely controlling the longer term response, further fusing into foreign body giant cells (FBGC), while bone cells make and remodel hydroxyl apatite. The above sequence results in the FBR that we call osseointegration and use for clinical purposes. However, the long-term clinical function is dependent on a foreign body equilibrium, that if disturbed may lead to impaired clinical function of the implant, through a breakdown process where macrophages are again activated and may further fuse into FBGCs, now seen in much greater numbers, resulting in the start of bone resorption - due to cells such as osteoclasts with different origins and possibly even macrophages degrading more bone than what is formed via osteoblastic activity - and rupture of mucosal seals, through complex mechanisms in need of further understanding. Infection may follow as a secondary event, further complicating the clinical scenario. Implant failure may ensue. CONCLUSIONS: Dentistry is still to embrace the concept of the biomaterials' healing- and immune-modulating effect when in contact with body tissues. The presented knowledge has the potential to open the door for a different interpretation of past, current, and future observations in dental implant science. From a clinical standpoint, it seems recommendable to react as rapidly as possible when facing peri-implant bone loss, trying to reestablish a foreign body equilibrium if with some bone resorption.

Does HIV infection have an impact upon dental implant osseointegration? A systematic review

OBJECTIVE: A systematic review is made to determine whether human immunodeficiency virus (HIV) infection has an impact upon dental implant osseointegration. STUDY DESIGN: A PubMed (MEDLINE) literature search was made of articles published up until 14 April 2014. The systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The quality of the studies included in the review was assessed using the Methodological Index for Nonrandomized Studies (MINORS) and levels of evidence (based on the University of Oxford's Center for Evidence Based Medicine criteria). RESULTS: The combinations of search terms resulted in a list of 132 titles. Nine studies finally met the inclusion criteria and were selected for inclusion in the systematic review. A total of 173 dental implants were placed in 80 patients (135 implants in 56 HIV-positive subjects and 38 implants in 24 HIV-negative patients), and a single loss of dental implant osseointegration was recorded in an HIV-positive patient. CONCLUSIONS: Our results suggest that dental implant placement in HIV-positive patients does not increase the dental implant failure rate. Prophylactic antibiotic treatment, the administration of highly active antiretroviral therapy, and control of the CD4+ T lymphocyte counts appear to be the main influencing factors in this respect. Given the few studies included in our systematic review, further prospective studies involving larger sample sizes and longer durations of follow-up are required in order to confirm the results obtained

Nuevos biomateriales: estudio in vivo del carburo de silicio como material osteointegrador / New biomaterials: in vivo study of silicon carbide as boneintegration material

Objetivo: Evaluar, mediante ensayos in vivo, la biocompatibilidad y el grado de penetración ósea en la microestructura porosa del carburo de silicio (SiC). Material y métodos: se implantaron en cóndilos femorales de conejos cilindros de SiC obtenidos a partir de maderas de pino y sapeli. Como material de referencia fueron utilizados cilindros de titanio. El sacrificio de los animales se realizó a las 12 semanas de implantación y se procedió al examen histológico de las muestras. Resultados: Comprobamos un crecimiento de trabéculas óseas, tanto en la superficie del implante como a través de su estructura porosa, sin apreciarse signos de inflamación ni aparición de tejido fibroso alrededor de la muestra. Estos resultados son confirmados mediante microscopía electrónica de barrido (SEM) y análisis de rayos X por dispersión de energías. Conclusión: El carburo de silicio biomórfico es una cerámica con excelentes propiedades mecánicas y porosidad interconectada que le confiere un especial atractivo de cara a sus aplicaciones biomédicas en implantes ortopédicos (AU)

Objective: To evaluate, using in vivo tests, the biocompatibility and the degree of bone penetration into the porous microstructure of silicon carbide (SiC). Material and methods: For this purpose cylindres of SiC obatained from wood of pine and sapeli were implanted in femoral condyles of rabbits. As reference material we used titanium cylinders. The slaughter of animals was performed at 12 weeks of implantation and proceeded to the histological examination of the samples. Results: We see a growth of bone trabeculae, both on the surface of the implant and through its porous structure, without signs of inflammation or appearance of fibrous tissue around the samples. These results are confirmed by scanning electron microscopy scanning (SEM) and X-ray analysis by dispersion of energies (EDS). Conclusion: Biomorphic silicon carbide (SiC) is a ceramic with excellent mechanical properties and interconnected porosity which gives a special attraction for their biomedical applications in orthopaedic implants (AU)

The profile of inflammatory cytokines in gingival crevicular fluid around healthy osseointegrated implants.

OBJECTIVE: Regardless of gingival health and subgingival microbiology, production of cytokines within peri-implant tissues may be different from that of teeth. The objective of this study was to describe the peri-implant levels of pro-inflammatory cytokines and subgingival microbiology in clinically healthy sites. MATERIALS AND METHODS: Subgingival plaque and gingival crevicular fluid (GCF) were obtained from 28 clinically healthy implants and 26 teeth selected from 24 individuals. Microbial composition was determined by selective anaerobic culture techniques. Pro-inflammatory cytokines were quantified by flow cytometry analysis of GCF. The concentration of cytokines between implants and teeth were compared with the independent t-test. RESULTS: The concentration of cytokines was higher in GCF from healthy implants than in teeth. The profile of cytokines was characteristic of an innate immune response. A more frequent detection of periodontopathic bacteria was observed in teeth than implants. Cultivable levels of periodontopathic bacteria were similar between implants and teeth. CONCLUSIONS: Despite gingival tissue health and scarce plaque accumulation, the profile of inflammatory cytokines in implant crevicular fluid was distinctive of an innate immune response and in higher concentration than in teeth. Other than bacterial stimulus, intrinsic factors related to implants may account for more cytokine production than teeth.

Titanium allergy: could it affect dental implant integration?

PURPOSE: Degradation products of metallic biomaterials including titanium may result in metal hypersensitivity reaction. Hypersensitivity to biomaterials is often described in terms of vague pain, skin rashes, fatigue and malaise and in some cases implant loss. Recently, titanium hypersensitivity has been suggested as one of the factors responsible for implant failure. Although titanium hypersensitivity is a growing concern, epidemiological data on incidence of titanium-related allergic reactions are still lacking. MATERIALS AND METHODS: A computer search of electronic databases primarily MEDLINE and PUBMED was performed with the following key words: 'titanium hypersensitivity', 'titanium allergy', 'titanium release' without any language restriction. Manual searches of the bibliographies of all the retrieved articles were also performed. In addition, a complementary hand search was also conducted to identify recent articles and case reports. RESULTS: Most of the literature comprised case reports and prospective in vivo/in vitro trials. One hundred and twenty-seven publications were selected for full text reading. The bulk of the literature originated from the orthopaedic discipline, reporting wear debris following knee/hip arthroplasties. The rest comprised osteosynthesis (plates/screws), oral implant/dental materials, dermatology/cardiac-pacemaker, pathology/cancer, biomaterials and general reports. CONCLUSION: This review of the literature indicates that titanium can induce hypersensitivity in susceptible patients and could play a critical role in implant failure. Furthermore, this review supports the need for long-term clinical and radiographic follow-up of all implant patients who are sensitive to metals. At present, we know little about titanium hypersensitivity, but it cannot be excluded as a reason for implant failure.

The correlation between gene expression of proinflammatory markers and bone formation during osseointegration with titanium implants.

An in vivo interfacial gene expression model combined with biomechanical analysis was used in order to determine the relationship between the molecular events taking place during osseointegration and the biomechanical stability of the implant. Anodically oxidized and machined, threaded titanium implants were characterized topographically, chemically and ultrastructurally. The implants were inserted in rat tibiae and the implant bone torsion stability was evaluated. After measurements, the implants were removed and analyzed with qPCR. Results showed an increase in the breakpoint torque of 140%, 170% and 190%, after 6, 14, and 28 days, respectively, at the oxidized implants as compared to the machined. Gene expression analysis revealed higher expression of runt related transcription factor-2 (Runx2) (after 28 d), osteocalcin (OC) and tartrate resistant acid phosphatase (TRAP) (after 6, 14 and 28 d) and cathepsin K (CATK) (after 6 and 14 d) at the oxidized implants. On the other hand, machined implants were associated with higher expression of tumor necrosis factor-α (TNF-α) (after 6 and 28 d) and interleukin-1ß (IL-1ß) (after 6, 14 and 28 d) compared to the oxidized implants. In conclusion, the favorable cellular and molecular events at the oxidized implants were in parallel with significantly stronger bone anchorage during osseointegration.

Particulate gold as an anti-inflammatory mediator in bone allograft---an animal study.

Morselized allograft is widely used when increased bone stock is needed in implant surgery. Gold ions liberated from metallic gold surfaces act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding and suppressing I-κ B-kinase activation. This study investigated the effect of 45-63 µm sized gold particles mixed in morselized allograft. It was hypothesized that bio-released gold ions would influence allograft reabsorption, increase mechanical stability, and further stimulate osseointegration. A pair of 10 mm long implants surrounded by a 2.5-mm gap was inserted in proximal part of each humerus in 10 sheep. Each gap was filled with morselized allograft with 1.29 mg gold particles or nothing. Observation time was 12 weeks. The gold ion liberation was visualized by autometallographic tracing and showed liberation of gold ions. Biomechanical push-out tests and stereological histomorphometric analyses showed no statistically significant differences in the two groups. Although particulate gold was primarily observed surrounded by bone marrow tissue, no obvious clinically relevant short-term effects could be measured using gold as an anti-inflammatory mediator. These findings show that the released gold ions have only influenced cells adjacent to the particles without influencing the fixation and illustrates gold ions' limited field of effect. We suggest a new design for orthopedic implants by introducing gold dots on the prosthesis surface. This aims at suppressing the inflammatory foci along the implant-bone zone and reduces the risk of chronic inflammation before aseptic loosening without affecting bone remodeling. This implant model will be investigated in further studies.

Osteointegración y osteobiomímesis de los implantes dentales: papel de las infecciones periimplantarias / Bone-integration and bone-biomimicry of dental implants: role of peri-implant infections

No disponible

No disponible

[Biocompatibility testing of various biomaterials as dependent on immune status]. / Biokompatibilitätstestung verschiedener Biomaterialien in Abhängigkeit vom Immunstatus.

INTRODUCTION: This study deals with the ingrowth behaviour of biomaterials (hydroxyapatite, cp-titanium, cobalt-chromium-molybdenum and PAEK) in relationship to the immunological competence in an animal model. Measured were the production of extracellular matrix (ECM) after implantation in non-immunocompetent naked mice and immunocompetent wild mice. Intention of the trial was to find out if either the immunological competence or the duration of implantation influences the quantity of produced ECM. In addition, the ingrowth behaviour was investigated under these conditions by using four different biomaterials. MATERIAL AND METHODS: Biomaterials (hydroxyapatite, cp-titanium, cobalt-chromium-molybdenum and PAEK) were implanted for 14 or 60 days, respectively. CLSM, SEM and SEM-EDX were used for analysis of the ECM and for measuring the distance between ECM and the biomaterials. CLSM was also used for the detection of collagen I and III as a parameter of the quality of osteointegration. RESULTS: In all cases a matrix grew on the surface of the biomaterials. The CLSM detected a co-localisation of collagen I and III. In the case of hydroxyapatite collagen I and III were found at a distance of 1 micro m over the surface. The largest space between the surface of the implant and the ECM was found in the case of PAEK. The smallest space was in the case of hydroxyapatite. In all investigated biomaterials the proportion of collagen I to collagen III varied through the duration of implantation. DISCUSSION: As is known from the literature we found different ingrowth behaviours on using different biomaterials. Furthermore, we found a statistically significant influence of the immunological competence of the host with regard to ECM production. We draw the conclusion that immunological competence improves the ingrowth behaviour of biomaterials.

The effects of hydroxyapatite coating and bone allograft on fixation of loaded experimental primary and revision implants.

We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability for the presence of particulate polyethylene. During this procedure, a sclerotic endosteal bone rim forms, and a dense fibrous membrane is engendered, having macrophages with ingested polyethylene and high levels of inflammatory cytokines. At the time of revision after 8 weeks, the cavity is revised with either a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included in each of the 8 treatment groups (total 64 implants in 32 dogs). The observation period was 4 weeks after revision. Outcome measures are based on histomorphometry and mechanical pushout properties. The revision setting was always inferior to its primary counterpart. Bone graft improved the revision fixation in all treatment groups, as also did the HA coating. The sole exception was revision-grafted HA implants, which reached the same fixation as primary Ti and HA grafted implants. The revision, which was less active in general, seems to need the dual stimulation of bone graft and HA implant surface, to obtain the same level of fixation associated with primary implants. Our findings suggest that the combination of HA implant and bone graft may be of benefit in the clinical revision implant setting.

Tissue reactions to particles of bone-substitute materials in intraosseous and heterotopic sites in rats: discrimination of osteoinduction, osteocompatibility, and inflammation.

Two rat models were used to characterize tissue-specific reactions to particles of bone-substitute materials: one for osteocompatibility in a healing tibial wound and the other in a heterotopic, subcutaneous site. Small, unicortical tibial wounds in rats healed spontaneously, beginning with the rapid proliferation of intramedullary woven bone. That temporary bone was resorbed by osteoclasts and finally, the cortical wound was healed with lamellar bone and the medullary space was repopulated with marrow. When various particulate materials were implanted into fresh wounds, three types of reactions were observed. (1) Demineralized bone powder (DBP) and non-resorbable calcium phosphate (nrCP) were incorporated into the reactive medullary and cortical bone. (2) Polymethylmetlhacrylate (PMMA) particles were surrounded with a fibrous layer, but did not impair bone healing. (3) Polyethylene (PE) shards and resorbable calcium phosphates (rCPs) were inflammatory and inhibited osseous repair. Subcutaneous sites showed osteoinductive, fibrotic, or inflammatory responses to these materials. Only DBP induced endochondral osteogenesis subcutaneously. The nrCP evoked a fibrous reaction. In contrast, rCPs, PMMA, and PE shards generated inflammatory reactions with each particle being surrounded by fibrous tissue and large multinucleated giant cells. In conclusion, only DBP showed osteoinductive as well as osteocompatible properties. The nrCP was osteocompatible. The rCPs stimulated various degrees of inflammatory responses. PMMA was osteocompatible and did not interfere with the bone healing process. PE was not osteocompatible and generated foreign body reactions in both sites. Use of the two sites distinguishes osteoinductive, osteocompatible, and inflammatory properties of particles of bone-substitute materials.

Early implant failures in patients treated with Brånemark System titanium dental implants: a retrospective study.

Implant failure has been associated with factors such as poor bone quality, insufficient bone volume, implant instability, unfavorable implant loading, and smoking habits. Infections and host responses may also be important factors in dental implant failure. The objectives of the present study were to identify various explanatory factors associated with titanium implant failure. Forty subjects with stage 1 non-osseointegrated titanium dental implants (NOTI) ad modum Brånemark and 40 age- and gender-matched control subjects with successfully osseointegrated titanium implants (SOTI) were studied. Clinical data and gamma G immunoglobulin (IgG) antibody titers were studied. An independent t test revealed that significantly longer implants were placed in subjects with SOTI (P < .05). Statistically significant differences in bone shape and resorption (BSR) scores were found between SOTI and NOTI (P < .05). Logistic regression analysis identified 3 significant explanatory outcome variables: serum antibody avidity scores for Bacteroides forsythus (P < .0001), serum antibody titers to Staphylococcus aureus (P < .001), and the BSR scores (P < .05). Antibody avidity to B forsythus and antibody titer to S aureus were therefore the 2 most important factors associated with early implant failures and with a significant predictive ability. This indicates that immunologic factors are involved in osseointegration.

Serum levels of interleukin-1 (IL-1), interleukin-6 (IL-6) and interleukin-8 (IL-8) in patients treated with dental implants.

The aim of the present study was to evaluate the levels of proinflammatory interleukins (IL)--IL-1, IL-6 and IL-8 in the blood of patients subjected to dental implant anchorage procedures. The study involved 10 generally healthy people aged 27-52, 4 men and 6 women. The patients were characterised by normal oral hygiene and lack of clinical symptoms of oral inflammation. Surgical procedures used Italian Logos system dental implants. The blood for analysis was collected three times: prior to surgery, one day and four months after the procedure before implant exposure. Interleukin levels were assayed with the ELISA method. The results were subjected to statistical analysis using Wicoxon's test. In all the cases examined soft tissue healing following the procedure was uneventful. The three consecutive examinations revealed similar IL-1 blood levels. Mean serum concentrations of IL-6 and IL-8 increased significantly in the second examination and returned to the close-to-initial values after 4 months. Increase of blood serum levels of IL-6 and IL-8 in the first day after implantation reflects local inflammation process caused by tissue impair.

Humoral immunity host factors in subjects with failing or successful titanium dental implants.

BACKGROUND: Treatment with titanium dental implants is in general successful. However, an unknown number of implants do not integrate and are removed either by exfoliation or at the time of second stage surgery. It would be of importance to identify subjects at risk and predict early implant failure. METHODS: In a retrospective study serum IgG antibody titers and avidity in sera from 40 subjects who had experienced titanium dental implant treatments with non-osseo-integration as the outcome (NOTI) and in sera from 40 age and gender matched control subjects who had received successful titanium dental implants (SOTI) were studied. Serum IgG titers to whole cell Actinomyces viscosus, Bacteroides forsythus, Porphyromonas gingivalis, Staphylococcus aureus, and Streptococcus intermedius sonicated antigen preparations were studied by ELISA. RESULTS: Serum IgG antibody titers to S. aureus were significantly higher in subjects with SOTI than in NOTI (p<0.001) suggesting that higher titers indicate protection against implant failure as a result of S. aureus infection. Statistically significant higher serum IgG antibody avidity to P. gingivalis and B. forsythus were found in subjects with SOTI than in subjects with NOTI (p<0.01 and p<0.001, respectively). Statistical analysis failed to demonstrate antibody titer or avidity differences to the other pathogens studied. The likelihood that SOTI was associated with a high OD reading for S. aureus was 13.1:1 (p<0.001). Whether subjects were edentulous or not, or if they had lost teeth because of periodontitis or caries did not seem to matter. CONCLUSION: Serum IgG antibodies relative to B. forsythus, P. gingivalis and S. aureus may be associated with the outcome of implant procedures and explain why early implant failures occur.