Tissue inhibitor of metalloproteinases-1, matrix metalloproteinases-1 and -8, and collagenase activity levels in peri-implant crevicular fluid after implantation

Can Peri-Implant Marginal Bone Loss Progression and a-MMP-8 Be Considered Indicators of the Subsequent Onset of Peri-Implantitis? A 5-Year Study

The aim of this retrospective study was to investigate the relationship between the amount of early bone remodeling, the marginal bone loss (MBL) progression, and the peri-implant sulcular fluid concentration of active metalloproteinase-8 (a-MMP-8) and the incidence of peri-implantitis (P) over 5 years of implant function. It has been documented that dental implants with a high degree of early marginal bone loss (MBL) are likely to achieve additional increased MBL during function. Moreover, it has been speculated that early increased MBL might be a predictive factor for the subsequent onset of peri-implant inflammatory diseases. Clinical and radiographic data at implant placement (T0) and restoration delivery (TR) at 6 months (T1), 2 years (T2), and 5 years (T5) post-loading were retrospectively collected. MBL levels/rates (MBLr) and peri-implant sulcular fluid levels/rates of a-MMP-8 were assessed at TR, T1, T2, and T5. Implants were divided into two groups: group 1 with peri-implantitis (P+) and group 2 without peri-implantitis (P−). A multi-level simple binary logistic regression, using generalized estimation equations (GEEs), was implemented to assess the association between each independent variable and P+. A receiver operating characteristics (ROC) curve was used to evaluate an optimal cutoff point for T1 MBL degree and a-MMP-8 level to discriminate between P+ and P− implants. A total of 80 patients who had received 80 implants between them (39 implants with a laser-microtextured collar surface (LMS) and 41 implants with a machined collar surface (MS)) were included. Periapical radiographs and a software package were used to measure MBL rates. Peri-implant sulcular implant fluid samples were analyzed by a chairside mouth-rinse test (ImplantSafe®) in combination with a digital reader (ORALyzer®). Twenty-four implants (six with an LMS and eighteen with an MS) were classified as P+. No statistically significant association was found between the amount of early bone remodeling, MBL progression, and MBLr and the incidence of peri-implantitis. Implants with a-MMP-8 levels >15.3 ng/mL at T1 presented a significantly higher probability of P+. The amount of early marginal bone remodeling cannot be considered as an indicator of the subsequent onset of P, whereas high a-MMP-8 levels 6 months after loading could have a distinct ability to predict P.

Effect of crystallinity and related surface properties on gene expression of primary fibroblasts

The biomaterial-cells interface is one of the most fundamental issues in tissue regeneration. Despite many years of scientific work, there is no clear answer to what determines the desired adhesion of cells and the synthesis of ECM proteins. Crystallinity is a characteristic of the structure that influences the surface and bulk properties of semicrystalline polymers used in medicine. The crystallinity of polycaprolactone (PCL) was varied by changing the molecular weight of the polymer and the annealing procedure. Measurements of surface free energy showed differences related to substrate crystallinity. Additionally, the water contact angle was determined to characterise surface wettability which was crucial in the analysis of protein absorption. X-ray photoelectron spectroscopy was used to indicate oxygen bonds amount on the surface. Finally, the impact of the crystallinity, and related properties were demonstrated on dermal fibroblasts' response. Cellular proliferation and expression of selected genes: α-SMA, collagen I, TIMP, integrin were analysed.

Correlation between Peri-Implant Marginal Bone Loss Progression and Peri-Implant Sulcular Fluid Levels of Metalloproteinase-8

Objectives: The aim of this retrospective study was to analyze peri-implant marginal bone loss levels/rates and peri-implant sulcular fluid levels/rates of metalloproteinase-8 in three timeframes (6 months post-surgery—restoration delivery (T0)—and 6 (T6) and 24 (T24)-months post-loading) and to evaluate if there is a correlation between peri-implant sulcular fluid levels of metalloproteinase-8 and peri-implant marginal bone loss progression. Materials and Methods: Two cohorts of patients undergoing implant surgery between January 2017 and January 2019 were selected in this retrospective study. A total of 39 patients received 39 implants with a laser-microtextured collar surface, and 41 subjects received 41 implants with a machined/smooth surface. For each patient, periapical radiographs and a software package were used to measure marginal bone loss rates. Implant fluid samples were analyzed by an enzyme-linked immunosorbent assay (ELISA) test. The modified plaque index, probing depth, and bleeding on probing were also recorded. Results: High marginal bone rates at T24 were strongly associated with elevated rates between T0 and T6. The levels of metalloproteinase-8 were significantly more elevated around implants with marginal bone loss, in relation to implants without marginal bone loss. Marginal bone loss (MBL) rates at 24 months were associated with initial bone loss rates and initial levels of metalloproteinase-8. Conclusions: Peri-implant marginal bone loss progression is statistically correlated to peri-implant sulcular fluid levels of metalloproteinase-8. Moreover, the initial high levels of marginal bone loss and metalloproteinase-8 can be considered as indicators of the subsequent progression of peri-implant MBL: implants with increased marginal bone loss rates and metalloproteinase-8 levels at 6 months after loading are likely to achieve additional marginal bone loss values.

The effect of conventional versus electronic cigarette use on treatment outcomes of peri-implant disease

Aim

To compare changes in clinical periodontal parameters (gingival consistency, colour, BOP, PI, PD) and changes of salivary inflammatory biomarkers (IL-1 β, IL-6, MMP-8, TNF- α and TIMP-1 between conventional, electronic cigarette smokers and non-smokers after peri-implant treatment.

Methods

Study participants were grouped into three groups (i) Conventional cigarette smokers (ii) Electronic cigarette smokers and (iii) non-smokers respectively. A total of 60 adult patients aged (40–56 years) with 60 implants with active per-impantitis was included.Clinical and Biological parameters were evaluated before surgical treatment at baseline, one, six and twelve month post treatment. Pearson’s chi-square test was used to compare the distribution of the categorical while Two-way repeated analysis of variance was used to compare the mean values of quantitative outcome variables among all study groups across the 4 time points.

Results

A total of 60 subjects (60 implants) were selected and classified into three groups as per their smoking method 20 participants in each group with one single targeted implant diagnosis with active peri-implantitis. The gingival colour, the change was statistically significant at one year of post treatment.The gingival consistency distribution across the three groups is not statistically significant at baseline, but it is statistically significant at one-month (p = 0.001), six months (p = 0.029) and at the completion of one-year (p = 0.018) post treatment. The plaque index of 100% of non-smokers had changed to ‘0’ and 35% change in cigarettes and 30% change in electronic smokers which is statistically significant (p = 0.016).The prevalence of BOP was observed in the three groups as 72%, 76.5% and 88.9% at baseline. The mean values of PD have shown statistically significant change across the three groups over the four-time intervals of observation (p = 0.024). The comparison of mean values of IL-1 β, IL-6 and TIMP-1 has shown statistically significant change across the three groups over the four intervals of observation (p < 0.0001).

Conclusions

Electronic cigarette smoking was found to be most prevalent risk indicator for peri-implantitis. Compromised response of peri-implantitis treatment both clinically and biologically was found more among electronic cigarette smokers when compared to conventional cigarette smokers and non-smokers.

Trial registration: This case-control study was conducted at King Saud University’s Dental College, Riyadh, Saudi Arabia, in accordance with “Helsinki Declaration of Human Studies” and approved by the Institutional Review Board (Reference no: 87563).

Comparison of RANKL and OPG levels in peri-implant crevicular fluid between healthy and diseased peri-implant tissues. A systematic review and meta-analysis

OBJECTIVES

To assess RANKL and OPG levels, as well as RANKL/OPG ratio, in peri-implant crevicular fluid (PICF), in dental implants presenting peri-implantitis (PI) in comparison to healthy implants (H) and to implants with peri-implant mucositis (MU).

MATERIALS AND METHODS

An electronic search based on the PICO framework, supplemented by hand searching, was conducted in MEDLINE and EMBASE, using the Ovid interface from 1996 up to and including the 17^th of December 2019 in order to identify relevant clinical studies. A combination of MeSH terms and text words was utilized for this purpose. Sequential screenings at the title, abstract, and full-text levels were performed independently and in duplicate. A random-effects meta-analysis was conducted and mean value standardized differences, between PI and H groups, were utilized as effect sizes.

RESULTS

Out of 1961 titles, which were revealed by the search strategy, 11 articles fulfilled the inclusion criteria and were incorporated in the systematic review. Meta-analytical processing was performed for RANKL (4 articles), OPG (5 articles), and RANKL/OPG ratio (5 articles) in PI and H groups. The total effect for RANKL mean differences between PI and H groups indicated a tendency but not a statistical significance (P = 0.078) in favor of the PI group, while no statistically significant differences were found for OPG and the ratio levels in the examined groups.

CONCLUSIONS

There is limited evidence that levels of the examined biomarkers, RANKL, and OPG as well as the RANKL/OPG ratio, in PICF, may be considered strong indicators for distinguishing between healthy and inflamed peri-implant sites.

CLINICAL RELEVANCE

Biomarker identification in PICF, which could differentiate between healthy and diseased dental implants, might represent a valuable non-invasive method suitable for implant pathology and implant therapy prognosis.

Biomarkers associated with periodontitis and peri-implantitis: a systematic review

Purpose

The pathology of peri-implantitis is still not fully understood and there have been recent challenges to the consensus on its aetiology and pathology, especially in comparison with periodontitis. The assessment of biomarkers allows a comparison of the pathology of these diseases. The aim of this systematic review was to answer the research question: “Is there a difference in the biomarkers associated with peri-implantitis compared with periodontitis in adult humans?”

Methods

Electronic databases were searched and screened, and a manual search was also undertaken. The inclusion criteria were adults with peri-implantitis who had been compared to adults with periodontitis with the outcome of biomarkers assessed via biopsies or crevicular fluid samples in primary or secondary care settings, as recorded in case-control, case series and retrospective, prospective and cross-sectional observational studies. Two reviewers independently screened titles and abstracts and assessed full text articles for eligibility and inclusion. Both reviewers independently extracted data and assessed risk of bias. Differences in biomarker levels were the primary outcome and a narrative review was undertaken due to the heterogeneity of studies.

Results

In total, 2,374 articles were identified in the search, of which 111 full-text articles were assessed for eligibility and 13 were included in the qualitative synthesis. Five of the 13 included studies were deemed to be at high risk of bias, with the others having moderate risk. All studies were cross-sectional and performed at university hospitals. Nine of the 13 included studies found significant differences in the levels of biomarkers or their ratios between peri-implantitis and periodontitis. Four of the studies found no significant differences.

Conclusions

Within the limitations of the included studies, it appears that there may be a difference in biomarker levels and ratios between peri-implantitis and periodontitis, suggesting that these disease processes are somewhat distinct.

Levels of Gene Expression of Immunological Biomarkers in Peri-Implant and Periodontal Tissues

This study compared the gene expression of the immunoinflammatory markers interleukin (IL)-6, IL-1ß, and tumor necrosis factor alpha (TNF-α), the matrix metalloproteinases (MMP)-1, -2, -8, and -9, and the tissue inhibitors of matrix metalloproteases (TIMP)-1 and -2 in the gingival tissue of individuals with periodontal and peri-implant disease. The study population included individuals with four periodontal statuses: periodontal health (PH group, n = 20); periodontitis (P group, n = 20); peri-implant health (PIH group, n = 20), and peri-implantitis (PI group, n = 20). Gingival biopsies were collected from one tooth per patient according to the inclusion criteria of each group. The mRNA levels of IL-6, IL-1ß, TNF-α, MMP-1, MMP-2, MMP-8, MMP-9, TIMP-1, and TIMP-2 were evaluated by qPCR. The levels of IL-1ß were significantly higher in the PI group when compared to the other groups (p < 0.05), while the levels of IL-6 were significantly higher in the groups with periodontal and peri-implant disease when compared with the healthy groups (p < 0.05); however, the levels of IL-6 did not differ between the PI and P groups (p > 0.05). For all other studied biomarkers, no significant differences were observed between groups (p > 0.05). IL-6 and IL-1ß presented higher levels of mRNA in diseased periodontal and peri-implant tissues. However, the expression of metalloproteinases and their inhibitors did not differ between the different periodontal statuses.

Gingival Response to Dental Implant: Comparison Study on the Effects of New Nanopored Laser-Treated vs. Traditional Healing Abutments

The health of peri-implant soft tissues is important for the long-term success rate of dental implants and the surface topography is pivotal in influencing it. Thus, the aim of this study was to evaluate, in human patients, the inflammatory mucosal microenvironment in the tissue surrounding a new, nanoscale, laser-treated healing abutment characterized by engineered nanopores versus a standard machined-surface. Analyses of anti- and pro-inflammatory markers, cytokeratins, desmosomal proteins and scanning electron microscopy were performed in 30 soft-tissue biopsies retrieved during second-stage surgery. The results demonstrate that the soft tissue surrounding the laser-treated surface was characterized by a lower grade of inflammation than the one facing the machined-surface, which, in turn, showed a disrupted epithelium and altered desmosomes. Moreover, higher adhesion of the epithelial cells on the laser-treated surface was detected compared to the machined one. In conclusion, the laser-treated surface topography seems to play an important role not only in cell adhesion, but also on the inflammatory makers’ expression of the soft tissue microenvironment. Thus, from a clinical point of view, the use of this kind of topography may be of crucial importance not only on healing abutments but also on prosthetic ones.

The modulation of the TREM-1/PGLYRP1/MMP-8 axis in peri-implant diseases

OBJECTIVES

The aim of this study is to investigate the expression of sTREM-1 and its ligand PGLYRP1, as well as the expression of MMP-8 and its inhibitor TIMP-1, in peri-implant diseases. As a secondary aim, we analyzed the influence of the concomitant existence of periodontitis in the expression of these biomarkers.

MATERIALS AND METHODS

This study included 77 patients (29 males and 48 females; mean age 55.0 ± 11.5), 18 having gingivitis, 16 having periodontitis, 20 having mucositis, and 23 having peri-implantitis. Patients were clinically examined, and unstimulated whole saliva was collected. sTREM-1, PGLYRP1, MMP-8, TIMP-1, and MMP-8/TIMP1 ratio were determined by ELISA.

RESULTS

The periodontitis group presented higher probing depth (PD) mean, and higher clinical attachment loss, compared with the other groups. The peri-implantitis group presented higher PD mean in implants compared to the mucositis group. Patients with PD ≥ 6 mm showed significantly higher levels of PGLYRP1, MMP-8, and MMP-8/TIMP-1 ratio than patients with PD < 6 mm. When all four markers were assessed, there were no significant differences between mucositis and peri-implantitis groups. Concomitant periodontitis resulted in higher significant levels of MMP-8 in patients with peri-implant disease.

CONCLUSION

We did not observe significant differences in the levels of the sTREM-1/PGLYRP1/MMP-8 axis between patients with periodontal and peri-implant diseases, suggesting that these markers are also involved in the inflammatory process around implants. Besides, the presence of periodontitis may affect the levels of MMP-8 in patients with peri-implant disease.

CLINICAL RELEVANCE

The sTREM-1/PGLYRP1/MMP-8 axis could be useful as potent markers in periodontal and peri-implant diseases.

The determination of pH of peri-implant crevicular fluid around one-piece and two-piece dental implants: A pilot study

There are two main groups of screw-type dental implant designs: one-piece and two-piece implants. Although success rates of both of these types of implants are high, none of them avoid complications, of which the most common are peri-implant mucositis and peri-implantitis. Current clinical diagnostic parameters are relatively noninvasive and cost-efficient; however, they are often not sensitive enough and fail to determine the activity of inflammation. The purpose of this study is to determine pH of peri-implant crevicular fluid (PICF) around one-piece and two-piece implants and pH of gingival crevicular fluid (GCF) around healthy teeth and to find out if our suggested method could function accurately for determination of pH of PICF and GCF. Thermo Fisher Scientific™ Orion™ 9863BN glass microelectrode was used to determine pH of PICF around 29 one-piece (ROOTT, TRATE AG) and 29 two-piece implants (multiple manufacturers) and pH of GCF around 29 healthy teeth. pH of PICF around two-piece implants was more acidic (P < 0.001). Average pH around one-piece implants was 6.46 and around two-piece implants was 6.15. Mean pH of GCF was 6.64. pH of PICF in women around two-piece implants was more alkaline (P < 0.05); no difference was found in control and one-piece implant groups. There was no statistically significant correlation found between age and pH of PICF and GFC. Design of dental implants has an impact on pH of PICF. Glass microelectrode is an appropriate tool for accurate determination of pH in PICF.

Does Peri-Implant Mucosa Have a Prognostic Value?

The need for keratinized tissue around implants remains a controversial topic. However, reconstruction of keratinized mucosa may be needed to facilitate restorative procedures, improve aesthetics, and control plaque during oral hygiene. Free gingival grafts, connective tissue grafts, allogenic/xenograft materials, and apically positioned flaps have been used to augment soft tissue around implants. Four different timing protocols have been explored with regard to soft-tissue augmentation: before and during implant placement, during the second-stage surgery, or after restoration. The timing and technique of soft-tissue augmentation remain controversial and lack support from literature. Long-term clinical studies to establish clear guidelines are warranted.

Effectiveness of an erbium-doped: yttrium, aluminum and garnet laser for treatment of peri-implant disease: Clinical, microbiological, and biochemical marker analyses

Background

The effectiveness of an erbium-doped: yttrium, aluminum and garnet (Er: YAG) laser (EYL) for the treatment of peri-implant disease (PID) remains unclear. The aim of this study was to compare non-surgical EYL therapy for PID with locally delivered minocycline hydrochloride (MC) ointment therapy by evaluating clinical, microbiological, and biochemical markers.

Material and Methods

Thirty-seven patients with PID were randomly assigned to either the EYL group (n = 18) or the MC group (n = 19). The clinical, microbiological, and biochemical markers at baseline and at 1 and 3 months after treatment were compared between the two groups. Subgingival plaque and peri-implant crevicular fluid (PICF) were collected from the diseased pockets.

Results

In the EYL group, probing pocket depth (PPD) was significantly decreased after treatment when compared with baseline. On the other hand, in the MC group, there was no significant decrease in PPD after treatment. Specific bacteria associated with PID were not determined. The counts of both Gram-positive and -negative species did not significantly decrease in the EYL group at 3 months after treatment. In the MC group, the counts of almost all bacterial species were significantly decreased after treatment. Biochemical marker analysis of PICF revealed significantly lower levels of metalloproteinase (MMP)-9 in the EYL group, as compared with the MC group at 3 months after treatment (p= 0.009).

Conclusions

Non-surgical therapy with an EYL for PID was clinically effective, with decreased MMP-9 levels in PICF, which may lead to reduced peri-implant tissue destruction. Key words:Er: YAG laser; peri-implant disease; biomarker; peri-implant crevicular fluid.

Calprotectin and cross-linked N-telopeptides of type I collagen levels in crevicular fluid from implant sites with peri-implant diseases: a pilot study

BACKGROUND

Peri-implant crevicular fluid (PICF) contains calprotectin and NTx, which are markers for inflammation and bone resorption, respectively. The aims of this pilot study were to compare calprotectin and NTx levels in PICF from implant sites with or without peri-implant diseases and to evaluate the usefulness of calprotectin and NTx as diagnostic markers for peri-implant diseases.

METHODS

Thirty-five patients with dental implants participated in this pilot study. PICF samples were collected from peri-implant disease sites (n = 40) and non-diseased (healthy) sites (n = 34) after clinical indicators including probing depth (PD), bleeding on probing (BOP), gingival index (GI), and bone loss (BL) rate were investigated. Calprotectin and NTx amounts in PICF were measured using their respective ELISA kits and then compared between diseased and healthy samples. The relationship between PICF calprotectin or NTx levels and clinical indicator levels was investigated. A receiver operating characteristic (ROC) curve analysis of calprotectin and NTx was performed to predict peri-implant diseases.

RESULTS

Calprotectin and NTx levels in PICF were significantly higher from peri-implant disease sites than from healthy sites. PICF calprotectin amounts correlated with PD, and its levels were significantly higher in the GI-1 and GI-2 groups than in the GI-0 group. PICF NTx amounts correlated with PD and the BL rate. ROC curves indicated that PICF calprotectin and NTx are useful biomarkers for peri-implant diseases.

CONCLUSIONS

Calprotectin and NTx in PICF have potential as biomarkers for the diagnosis of peri-implant diseases.

Biomarkers associated with periimplant diseases

PURPOSE

Recently, implantology has shifted its focus from implant placement to periimplant disease early detection, prevention, and treatment. The purpose of this article was to review the current understanding of the biomarkers associated with periimplant diseases.

MATERIALS AND METHODS

A search of PubMed was conducted up to August 2013 with keywords "peri-implantitis" and "biomarkers." Selected articles addressed the relationship between biomarkers and periimplant mucositis or peri-implantitis.

RESULTS

Biomarkers have been shown to possess potential in detecting periimplant diseases. For example, interleukin (IL)-1β levels were shown to be a good marker to detect periimplant mucositis lesions before they progress to peri-implantitis. Matrix metalloproteinase (MMP)-8 levels in periimplant sulcus fluid may be useful for monitoring the progression of periimplant disease. Osteoprotegerin (OPG) and receptor activator of NFκB ligand (RANKL) were found to be significantly higher in peri-implantitis sites compared with healthy implant sites.

CONCLUSION

Biomarkers such as IL-1β, MMP-8, OPG, RANKL, and others have shown promising outcomes in differentiating from periimplant disease to health. However, because of varying results, additional evidence is needed to validate the links reported.

Peri-Implant Crevicular Fluid Analysis, Enzymes and Biomarkers: a Systemetic Review

OBJECTIVES

To review the current understanding of the biomarkers and enzymes associated with different forms peri-implant diseases and how their level changes influence the pathogenesis of the inflammatory diseases around dental implants.

MATERIAL AND METHODS

An electronic search in two different databases was performed including MEDLINE (PubMed) and EMBASE between 1996 to 2016. Human studies analyse peri-implant crevicular fluid (PICF) biomarker and enzyme levels of implants having peri-implant mucositis and peri-implantitis published in English language, were evaluated. A systematic review was performed to assess which biomarkers and enzymes in PICF were used to identify the inflammatory conditions around dental implants.

RESULTS

Fifty-one articles were identified of which 41 were further evaluated and included in the analysis. Due to significant heterogeneity between included studies, a meta-analysis could not be performed. Instead, a systematic descriptive review was performed.

CONCLUSIONS

Biomarkers and enzymes in peri-implant crevicular fluid have shown promising results in differentiating from peri-implant disease condition to health. However, due to inconsistent results and acquiring much evidence from cross-sectional studies, additional evidence supported by randomized-controlled trials is needed to validate the links reported.

Protein biomarkers and microbial profiles in peri-implantitis

OBJECTIVES

The aim of the present investigation was to determine the profile of peri-implant crevicular fluid (PICF) biomarkers combined with microbial profiles from implants with healthy peri-implant tissues and peri-implantitis to assess real-time disease activity.

MATERIAL AND METHODS

Sixty-eight patients were included in this cross-sectional study. They were divided into two groups: 34 patients with at least one healthy implant (control) and 34 with at least one peri-implantitis affected implant (test). Total DNA content and qPCR analysis for periodontal bacteria obtained from subgingival plaque samples (Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) and a PICF analysis for IL-1β, VEGF, MMP-8, TIMP-2, and OPG were performed. The individual and combined diagnostic ability of each biomarker for peri-implantitis and target bacterial species were analyzed.

RESULTS

The mean concentration of IL-1β (44.6 vs. 135.8 pg/ml; P < 0.001), TIMP-2 (5488.3 vs. 9771.8 pg/ml; P = 0.001), VEGF (59.1 vs. 129.0 pg/ml; P = 0.012), and OPG (66.5 vs. 111.7 pg/ml; P = 0.050) was increased in the peri-implantitis patients. The mean expression of MMP-8 (6029.2 vs. 5943.1 pg/ml; P = 0.454) and did not reveal a meaningful difference among groups. Total bacterial DNA of selected microorganisms was associated with a threefold or greater increase in peri-implantitis although no statistical significant difference. The ability to diagnose diseased sites was enhanced by T. denticola combined with IL-1β, VEGF, and TIMP-2 PICF levels.

CONCLUSION

The present data suggest that the increased levels of the selected PICF-derived biomarkers of periodontal tissue inflammation, matrix degradation/regulation, and alveolar bone turnover/resorption combined with site-specific microbial profiles may be associated with peri-implantitis and could have potential as predictors of peri-implant diseases.

Comparison of peri-implant crevicular fluid levels of adrenomedullin and human beta defensins 1 and 2 from mandibular implants with different implant stability quotient levels in nonsmoker patients

BACKGROUND AND OBJECTIVE

To achieve satisfactory osseointegration, primary stability and healthy peri-implant tissue must be available. In this study, our objective was to compare the adrenomedullin, human beta-defensin (hBD)-1 and hBD-2 levels in implants with different implant stability quotient (ISQ) values and with different peri-implant tissue health values in the peri-implant crevicular fluid.

MATERIAL AND METHODS

Thirty patients with 60 endosseous osseointegrated implants were included in this study. Following the completion of the osseointegration process, these implants were divided into two main groups: a group of 15 implants with peri-implantitis (peri-implantitis: 40 ≤ ISQ ≤ 80 peri-implantitis, n = 15) and a group of 45 implants with healthy peri-implant tissue. The healthy peri-implant tissue group was further divided into three subgroups according to their ISQ values (Healthy-60: 60 ≤ ISQ ≤ 70, healthy peri-implant, n = 15; Healthy-80: 71 ≤ ISQ ≤ 80, healthy peri-implant, n = 15; and Healthy-100: 81 ≤ ISQ ≤ 100, healthy peri-implant, n = 15). The levels of adrenomedullin, hBD-1 and hBD-2 in the peri-implant crevicular fluid were assessed using ELISAs.

RESULTS

When the peri-implant clinical measurements were compared within groups, they were found to be highest in the peri-implantitis group and lowest in the Healthy-100 group. The adrenomedullin, hBD-1 and hBD-2 levels in the peri-implant crevicular fluid of the peri-implantitis group were found to be significantly higher than those in the Healthy-60, Healthy-80 and Healthy-100 groups. When only the healthy peri-implant tissue groups were evaluated, the adrenomedullin, hBD-1 and hBD-2 levels in the peri-implant crevicular fluid of the Healthy-60 group were found to be significantly higher than those in the Healthy-80 and Healthy-100 groups. The lowest adrenomedullin, hBD-1 and hBD-2 levels were observed in the Healthy-100 group.

CONCLUSION

In cases of peri-implantitis, higher adrenomedullin, hBD-1 and hBD-2 levels were observed. These results indicate the presence of a tissue response to prevent the creation of a pathological environment in the peri-implant tissue. In groups with healthy peri-implant tissues, the ISQ value decreases as the adrenomedullin, hBD-1 and hBD-2 levels increase. This condition is thought to be caused by increased dental plaque accumulation and bone resorption in addition to increased lateral implant movements and colonization of microorganisms in the microcavities between the implant elements.

Peri-implant versus periodontal wound healing

AIM

Peri-implant gingival healing following one-stage implant placement was investigated and compared to periodontal healing.

METHODS

Healing at surgical sites [implant (I) and adjacent teeth (T+)] was compared to non-operated tooth (T-) in non-smokers receiving one-stage implant. Periodontal Indices (PI, GI) were recorded at surgery and up to 12 weeks post-operatively. Peri-implant (PICF) and gingival crevicular fluids (GCF) were analysed for cytokines, collagenases and inhibitors. Data were analysed by linear mixed model regression analysis and repeated measures anova.

RESULTS

Forty patients (22 females; 21-74 years old) completed the study. Surgical site GI, increased at week 1, decreased significantly during early healing (weeks 1-3; p = 0.0003) and continually decreased during late healing (weeks 6-12) for I (p < 0.01). PICF volume decreased threefold by week 12 (p = 0.0003). IL-6, IL-8, MIP-1β and TIMP-1 levels significantly increased at surgical sites at week one, significantly decreasing thereafter (p < 0.016). Week one IL-6, IL-8 and MIP-1β levels were ~threefold higher and TIMP-1 levels 63% higher, at I compared to T+ (p = 0.001).

CONCLUSION

Peri-implant gingival healing, as determined by crevicular fluid molecular composition, differs from periodontal healing. The observed differences suggest that peri-implant tissues, compared to periodontal tissues, represent a higher pro-inflammatory state.

Matrix metalloproteinase-8 is the major potential collagenase in active peri-implantitis

PURPOSE

Current clinical procedures to control or regenerate bone loss due to peri-implantitis are not predictable neither accomplish complete resolution. Therefore, early detection of the onset and the active periods of bone loss are crucial for prevention of extensive peri-implant bone resorption. This study aimed to determine a possible association between the presence of collagenases (MMP-1, MMP-8 and MMP-13) in peri-implant sulcular fluid (PISF) and active periods of bone loss by annually adjusted vertical bone loss (AVBL) measurements.

METHODS

Intended sample consisted of 76 consecutive patients who received oral implant treatment at the Fixed Prosthodontic Clinic of Okayama University Hospital from 1990 to 2000. Twelve subjects were lost to follow-up or refused to participate. Consequently, the actual sample consisted of 64 patients who were followed-up for at least one year. Those patients with AVBL>0.6mm were included in the severe peri-implantitis group, and randomly selected, age-, gender- and implantation site-matched healthy patients (AVBL<0.3mm) comprised the control group. PISF samples were collected from both groups and further analyzed by western blot for detection of collagenases.

RESULTS

Four patients presented severe peri-implantitis. MMP-8 was the only collagenase detected in peri-implant sites with ongoing bone loss. PISF samples from control group showed no positive reactions to any collagenase.

CONCLUSION

This study showed MMP-8 as a possible marker for progressive bone loss in peri-implantitis.

Clinical, radiographic, microbiological, and immunological outcomes of flapped vs. flapless dental implants: a prospective randomized controlled clinical trial

OBJECTIVES

The objective of this study was to compare the placement of flapped vs. flapless dental implants utilizing clinical, radiographic, microbiological, and immunological parameters.

MATERIAL AND METHODS

A total of 20 patients received 30 dental implants following a one-stage protocol. The patients were randomly assigned into two study groups: control group with 15 flapped implants and test group with 15 flapless implants. Follow-up examinations were carried out after 1, 2, 6, and 12 weeks. Clinical recordings, sulcular fluid sampling, microbiological analysis, and digital subtraction radiography were utilized to compare the two surgical approaches.

RESULTS

Peri-implant sulcus depth was significantly greater in flapped implants at both 6 and 12 postsurgical weeks (P < 0.001). Flapped implants showed crestal bone loss (0.29 ± 0.06 mm), whereas no bone resorption was detected around flapless implants. Matrix metalloproteinase-8 values were higher to a statistically significant level in the control group at 1 (P = 0.003) and 6 weeks (P = 0.007) after placement. In the test group, the presence of Porphyromonas gingivalis was significantly higher at the 2nd postoperative week (P = 0.005), whereas the counts of Tannerella forsythia were significantly elevated at the 1st (P = 0.005), 2nd (P = 0.001), and 12th (P = 0.002) postoperative weeks, possibly indicating an earlier formation and maturation of the peri-implant sulcus. Patients reported more pain after flapped implant placement.

CONCLUSIONS

Flapless implant placement yielded improved clinical, radiographic, and immunological outcomes compared with flapped implantation. In addition, patients seem to better withstand flapless implant placement.

Human bone disorders: pathological role and diagnostic potential of matrix metalloproteinases

Bone undergoes continuous remodeling under physiological and pathological conditions. Failure of the regulation of this process leads to several disorders involving bone erosion. This series of events is mainly based on the action of proteinases, particularly matrix metalloproteinases (MMPs). MMPs have been recently suggested as potential bone resorption markers which could be added to the commonly used ones, in order to predict outcome of disease processes and healing, and to monitor disease response to treatment. As for classical biochemical bone markers, MMPs are far from being applied in primary clinical diagnosis, but they could be promising in some cases for disease prognosis. MMPs as bone remodeling biomarkers could provide information that boosts our understanding of the prognosis, disease activity and pathogenesis of bone disorders. Clarifying the MMPs' role in bone remodeling and healing could potentially help predict disease progression and the effects of direct specific therapy.

In vivo gene expression in response to anodically oxidized versus machined titanium implants

A quantitative polymerase chain reaction technique (qPCR) in combination with scanning electron microscopy was applied for the evaluation of early gene expression response and cellular reactions close to titanium implants. Anodically oxidized and machined titanium miniscrews were inserted in rat tibiae. After 1, 3, and 6 days the implants were unscrewed and the surrounding bone was retrieved using trephines. Both the implants and bone were analyzed with qPCR. A greater amount of cells, as indicated with higher expression of 18S, was detected on the oxidized surface after 1 and 6 days. Significantly higher osteocalcin (at day 6), alkaline phosphatase (at days 3 and 6), and cathepsin K (at day 3) expression was demonstrated for the oxidized surface. Higher expression of tumor necrosis factor-alpha (at day 1) and interleukin-1beta (at days 1 and 6) was detected on the machined surfaces. SEM revealed a higher amount of mesenchymal-like cells on the oxidized surface. The results show that the rapid recruitment of mesenchymal cells, the rapid triggering of gene expression crucial for bone remodeling and the transient nature of inflammation, constitute biological mechanisms for osseointegration, and high implant stability associated with anodically oxidized implants.

Early wound healing following one-stage dental implant placement with and without antibiotic prophylaxis: a pilot study

BACKGROUND

One-stage implant placement has clinically acceptable treatment outcomes. Among other advantages, it may allow investigation of early wound healing. The purpose of this pilot study was to determine whether peri-implant crevicular fluid (PICF) can be used to detect early changes around implants placed with one-stage surgical protocol following 1 week of healing.

METHODS

Twenty subjects (11 males and nine females; aged 22 to 72 years; two smokers) were included. Exclusion criteria were allergies to amoxicillin and systemic conditions that may affect healing. Subjects had a healthy periodontium and needed a single implant; eight received antibiotic prophylaxis, and 12 served as controls. Clinical healing was evaluated with plaque and gingival indices (PI and GI, respectively). Gingival crevicular fluid (GCF) from the surgical site was obtained prior to the surgery, whereas PICF was collected at the 1-week visit. Enzyme-linked immunosorbent assay was used to determine GCF/PICF interleukin (IL)-1beta and -8 concentrations. Peripheral blood and GCF antibiotic levels were measured by high-performance liquid chromatography.

RESULTS

Postoperative PI and GI were slightly increased. Total GCF and PICF volumes did not show a significant difference between appointments. There was an increase in PICF IL-1beta and -8 levels at 1 week postoperatively. Mean amoxicillin serum concentration was 5.1 +/- 2 microg/ml at 1 to 4 hours following the initial dose, whereas GCF amoxicillin levels were below the limit of detection. Antibiotic prophylaxis had a modest effect on clinical indices (PI and GI) and no appreciable effect on biomarkers.

CONCLUSIONS

PICF content can be studied as early as 1 week following one-stage implant placement. The results raise doubts regarding the clinical usefulness of amoxicillin prophylaxis.

Reliability of findings around healthy implants in association with oral hygiene measures: a clinical, microbiological, and immunological follow-up in edentulous patients

OBJECTIVES

To assess the performance of clinical, microbiological, and immunological diagnosis of peri-implant health and the influence of professional hygiene measures on them.

MATERIAL AND METHODS

Twenty-one edentulous patients with oral implants supporting a lower overdenture were followed up over 3 months beginning 1 week before their annual recall visit. Hygiene scores, probing depth, bleeding on probing (BOP), implant stability, gingival crevicular fluid (GCF) volume, sulcular interleukin-1beta (IL-1beta) and prostaglandin E2 (PGE2) concentrations, and relative concentrations of five bacterial species (polymerase chain reaction) were investigated. Measurement variation was assessed as a function of (a) intra- and (b) inter-examiner reliability, (c) inter-implant variation in each patient, (d) time, and (e) effect of hygiene measures by accuracy, repeatability, reproducibility, and visualization with the Bland and Altman Plot.

RESULTS

Measurement means and accuracy (in parentheses) were as follows: GCF volume 1.5 microl (1.5), Interleukin-1beta 8 ng/ml (26), PGE2 63 ng/ml (185), bacteria sum score 0.2 (0.7), plaque score 1 (1), BOP score 0 (1), Periotest value -4 (3), resonance frequency analysis ISQ 66 (11), and pocket probing depth 2.3 mm (0.7). No finding exhibited any statistically significant measurement variation as explained by accuracy, repeatability, or reproducibility. Bland and Altman Plots revealed insufficient agreement for replicated BOP assessments. A short post-treatment reduction in plaque and BOP scores was visually apparent. Still, professional oral hygiene measures exerted no sustained influence on the clinical and biochemical appearance of the peri-implant tissues.

CONCLUSION

All findings except BOP showed statistically acceptable repeatability and moderate vulnerability to influences present 'chairside' in clinical practice.

Analysis of Aspartate Aminotransferase and Alkaline Phosphatase in Crevicular Fluid From Implants With and Without Peri-implantitis

PURPOSE

The aim of this investigation was to determine the presence of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in crevicular fluid collected from implants with and without clinical and radiographic signs of peri-implantitis.

MATERIALS AND METHODS

There were 17 implants with symptoms of peri-implantitis in 12 subjects, including 4 females and 8 males, compared to 17 implants in 13 subjects, including 5 females and 8 males, with healthy peri-implant tissues. Filter paper strips were used to collect peri-implant crevicular fluid for 30 seconds in the base of the crevice/pocket. SPSS statistical software (SPSS, Inc., Chicago, IL) was used to determine AST and ALP activity.

RESULTS

The results showed that there was a significant difference in the activity of AST and ALP between the 2 study groups (P < 0.0001). AST activity was significantly associated with the amount of bleeding on probing (P = 0.02), but no statistical correlation was found between ALP activity and increased amount of bleeding on probing (P = 0.05).

CONCLUSIONS

Within the limits of this study, our results may suggest that peri-implant crevicular fluid analysis could be further investigated in longitudinal studies as a suitable diagnostic strategy in the evaluation of dental implants.

Relationship between gelatinases and bone turnover in the healing bone defect

PURPOSE

The aim of this pilot study was to determine the relationship between gelatinase (MMP-9 and MMP-2) markers of soft tissue inflammation/turnover at the bone/soft tissue interface and bone turnover (osteocalcin [OC], pyridinoline cross-linked carboxyl-terminal telopeptide of type 1 collagen [ICTP], and bone fill) during healing of an alveolar bone defect.

MATERIALS AND METHODS

Ten subjects undergoing oral surgery had a 5 x 5-mm trephine defect created on an edentulous ridge and were sampled at the bone/soft tissue interface at baseline (prior to flap reflection), 2 weeks and 12 weeks postsurgery, using a novel bone wash device. Recovered irrigants were analyzed for MMP-9 and MMP-2 by gelatin zymography, OC and ICTP with radioimmunoassays, and albumin (ALB; to normalize markers for blood content) with a sandwich enzyme-linked immunosorbent assay. Bone fill at 12 weeks was analyzed by radiographic absorptiometry.

RESULTS

All markers of enzymatic activity and bone turnover varied significantly across time (P < or = .03), with bone turnover markers OC and ICTP decreasing between baseline and 2 weeks, and MMP-9 and MMP-2 increased. Measures generally returned to near baseline levels after 12 weeks. MMP-9 versus MMP-2 (r = 0.97, P < .0001) and OC versus ICTP (r = 0.38, P = .048) were correlated with each other, while MMP-9 and MMP-2 were negatively correlated with ICTP (r = -0.48, P = .011 and r = -0.62, P = .006, respectively). MMP-9 was negatively correlated with subsequent bone fill (r = -0.63, P = .07).

CONCLUSIONS

Bone wash sampling showed that gelatinase activity at 2 weeks following creation of an alveolar defect appeared to decrease bone turnover and eventual bone fill, suggesting benefits for anti-MMP therapy during wound healing.

Histochemical and immunohistochemical evaluation of gingival collagen and metalloproteinases in peri-implantitis

The extra-cellular matrix of the gingival tissue plays an important role in the homeostasis of dental implants. In this work we have studied immunohistochemically the distribution of collagen I-III-IV-V, tenascin, metalloproteinases (MMP) 1-3-8-13 and TIMP-1 in three groups of patients: (1) subjects with natural teeth (healthy periodontal tissue), (2) subjects with normal peri-implant mucosa and (3) subjects with clinically evident peri-implantitis. The immunolabelling for collagen I-III-IV showed a similar pattern in all three groups. The labelling for collagen V increased in lamina propria of healthy peri-implant tissue and peri-implantitis. Tenascin immunolabelling in healthy and peri-implant tissues was scattered in lamina propria. In peri-implantitis tenascin immunolabelling increased mainly near to the basal lamina. The MMP-1-3-8 and TIMP-1 immunolabelling were very faint and localized in the stroma in all three groups. In healthy and peri-implant tissues MMP-13 immunolabelling was found in the lamina propria whereas in peri-implantitis MMP-13 immunolabelling was also in epithelium. On the whole, these data suggest that in the extracellular matrix of peri-implantitis there are alterations of collagen V, tenascin and MMP-13 patterns.

Serum, Saliva, and Gingival Crevicular Fluid Osteocalcin: Their Relation to Periodontal Status and Bone Mineral Density in Postmenopausal Women

BACKGROUND

Periodontitis and osteoporosis are characterized by the loss of bone mass. Osteocalcin levels have been postulated as a marker of inhibition of bone formation. The aim of the present study was to assess plasma, saliva, and gingival crevicular fluid (GCF) levels of osteocalcin and correlate them with periodontitis and osteoporosis.

METHODS

Seventy-three postmenopausal women, over 35 years old, were recruited for the study. Serum, saliva, and GCF osteocalcin were measured. Vertebral bone mineral density was measured by dual-energy x-ray absorptiometry. Differences between groups were assessed by analysis of variance (ANOVA), chi-square test, and non-parametric Kruskal-Wallis test.

RESULTS

Thirty-four (46.6%) were classified in the normal healthy bone group, 11 women (15.1%) in the osteopenic group, and 28 women (38.4%) in the osteoporotic group. No statistically significant differences between these densitometric groups were observed in probing depth (P = 0.24); clinical attachment level (P = 0.11); or mean osteocalcin concentrations in serum, saliva, and GCF. Twenty-seven (37.0%) of the women were classified without periodontitis (NPG) and 63.0% (N = 46) with periodontal disease (PG). There were no statistical differences in serum and saliva osteocalcin concentrations between these two groups. GCF osteocalcin concentrations were significantly higher in the PG women than in the NPG group (P = 0.008). Mean probing depth correlated significantly with GCF osteocalcin concentrations (r = 0.35; P = 0.002).

CONCLUSION

The results further support the concept that osteocalcin levels in GCF correlates with periodontal but not with osteoporosis status.

Levels and molecular forms of MMP-7 (matrilysin-1) and MMP-8 (collagenase-2) in diseased human peri-implant sulcular fluid

OBJECTIVES

Matrix metalloproteinases (MMPs) play crucial role in various tissue destructive inflammatory processes by degrading almost all peri-cellular and basement membrane components. MMP-8 (collagenase-2) is the major MMP in periodontitis. MMP-7 (matrilysin-1), in addition to its ability to degrade matrix and basement membrane components, activates other latent pro-MMPs and defensins, host cell-derived antimicrobial cryptidins. The aim of the present study was to characterize the relationship, levels and molecular forms of MMP-8 and MMP-7 in diseased peri-implant sulcular fluid (PISF).

MATERIALS AND METHODS

Seventy-two human dental implant fluid samples were collected with filter paper strips from peri-implant sulci from healthy and untreated diseased implant sites. Gingival index (GI) and/or bone resorption (BR) were also recorded. Western immunoblot method with polyclonal anti-human-MMP-8 and monoclonal anti-human-MMP-7 antibodies was used, and immunoreactivities were quantified with computer scanning program. The effects of MMP inhibitors (doxycycline, chemically modified tetracycline-3, clodronate, CTT-peptide and marimastat) were studied on the activity of recombinant human matrilysin-1 (MMP-7) using beta-casein degradation assay.

RESULTS

The levels of active forms of MMP-8 and MMP-7 were significantly elevated in diseased PISF in relation to healthy PISF. Furthermore, MMP-8 and MMP-7 levels correlated significantly to each other and GI. MMP-8 was present not only as bands corresponding to 75-kDa polymorphonuclear leukocyte (PMN) -type pro- and 65-kDa active forms, but also as 55-kDa non-PMN-type pro- and 45-kDa active forms. Immunoreactivities > 80 kDa most likely represented dimeric and/or inhibitor-bound MMP-8 complexes and the low molecular weight (< 30 kDa) species were apparently degraded fragments. In diseased PISF, 19-21-kDa active MMP-7 and 28-30-kDa pro-MMP-7 species were detected, and the active 19-21-kDa forms of MMP-7 predominated in diseased PISF. Doxycycline (50 micro m and 250 micro m), chemically modified non-antimicrobial tetracycline (CMT-3) (50 micro m and 100 micro m), clodronate (a bisphosphonate, 20 micro m and 500 micro m) and the cyclic CTT (CTTHWGFTLC)-peptide (125 micro m and 250 micro m), all known broad-spectrum or selective MMP-inhibitors, did not inhibit the activity of human recombinant MMP-7; only marimastat (1 micro m and 5 micro m) inhibited MMP-7.

DISCUSSION

Increased immunoreactivities of the active MMP-8 and MMP-7 species in PISF from diseased peri-implantitis lesions eventually reflect the stage and course of peri-implantitis; MMP-7 may potentially act as MMP-8 and defensin activator in diseased PISF.

CONCLUSION

The elevated levels of MMP-8 and matrilysin-1/MMP-7 were identified in active forms in diseased PISF, but MMP-7 was less prominent. MMP inhibitors, potential future tissue protective drugs, seemingly do not interfere with the defensive antibacterial action of MMP-7.

Laminin-5 gamma2-chain and collagenase-2 (MMP-8) in human peri-implant sulcular fluid

Laminin-5 (LN-5) is an important epithelial cell-derived structural and adhesive component in hemidesmosomes and basement membranes (BM). In peri-implant tissue, gingival BM underlies the junctional epithelium (JE) and reflects the peri-implant health. Matrix metalloproteinase-8 (MMP-8 or collagenase-2) is one of the key mediators of periodontal tissue destruction. Western immunoblotting with image analysis was used to quantitate the molecular forms of LN-5 gamma2-chain and MMP-8 in peri-implant sulcular fluid (PISF) from healthy and diseased implants. These observations were related to the recorded gingival (GI) and bone resorption (BR) indices of the studied sites. Altogether, 72 PISF samples from osseointegrated dental implants were examined. Significantly elevated levels of fragmented LN-5 gamma2-chain species (45 and 70 kDa) and MMP-8 immunoreactivities were observed in diseased PISF in relation to healthy PISF. The elevated levels of both LN-5 gamma2-chain 45 and 70 kDa fragments and MMP-8 in diseased PISF from peri-mucositis (BR = 0) and peri-implantitis (BR >/= 1) lesions strongly correlated with elevated GI. Low levels - almost comparable to those seen in healthy control PISF - were seen in PISF from peri-implantitis lesions (BR >/= 1) with no GI. Activation of 75 kDa neutrophil (PMN)-type proMMP-8 to 10 kDa lower-molecular-size active forms was especially detected in PISF from peri-implantitis with elevated GI. These cross-sectional findings indicate that elevated MMP-8 and LN-5 gamma2-chain fragment levels in PISF can reflect the active phase of the inflammatory peri-implant disease. Longitudinal studies are required to assess their use, either alone or in combination as molecular biochemical PISF markers, to predict the risk of progression of peri-implantitis, as well as to monitor the impact of treatment of the disease.

Osteocalcin, deoxypyridinoline and interleukin-1beta in peri-implant crevicular fluid of patients with peri-implantitis

The aim of the present study was to analyze the levels of osteocalcin, deoxypyridinoline (Dpd) and interleukin-1beta as markers of bone metabolism in peri-implant crevicular fluid (PICF) from peri-implantitis patients. PICF was sampled from a total of 34 endosseous titanium implants from 16 patients; nine females (mean age 52.8, range 40-62 years) and seven males (mean age 56.0, range 36-66 years). The implants had been in place for a period of 9-112 months (mean; 35.8 months) since the loading. These sites were categorized as six peri-implantitis, eight peri-implant mucositis and 20 healthy implant. PICF volume from peri-implantitis sites was significantly higher than mucositis and healthy implant sites (P < 0.01). Osteocalcin levels in PICF from mucositis sites were significantly higher than healthy implants (P < 0.05), whereas peri-implantitis sites were not significantly different from either mucositis or healthy implant sites. Dpd could not be detected in any of the samples examined. IL-1beta levels in PICF from peri-implantitis sites were significantly higher than levels from peri-implant mucositis (P < 0.05) and healthy implant sites (P < 0.01). In conclusion, osteocalcin in PICF may reflect increased local bone turnover around implants. Further, IL-1beta should be a useful marker for peri-implant inflammation.