Possible impact of inflammatory status on C‐telopeptide pyridinoline cross‐links of Type I collagen and osteocalcin levels around oral implants with peri‐implantitis: a controlled clinical trial

Summary Detection of progression level of peri‐implantitis may help in the prevention of oral implant failure. C‐telopeptide pyridinoline crosslinks of Type I collagen (ICTP) and osteocalcin (OC) are specific markers of bone turnover and bone degradation. Determination of the ICTP and OC levels in the peri‐implant sulcus fluid (PISF) may predict the metabolic and/or inflammatory changes in the peri‐implant bone. The aim of this clinical study was to evaluate ICTP and OC levels in the PISF for oral implants with and without peri‐implant bone destruction and correlate these levels with the traditional clinical peri‐implant parameters (probing depth, plaque index, gingival index and gingival bleeding time index) and radiographic bone level measurements. Fifteen patients with 30 peri‐implant sites with bone destruction (radiographic bone loss) and health were included. Clinical parameters were measured and PISF was collected from the sites. Peri‐implant sulcus fluid ICTP and OC levels were detected by radioimmunoassay technique from PISF samples. All clinical parameters demonstrated a significant increase in peri‐implantitis sites compared with healthy sites. The PISF volume of the peri‐implantitis sites was also significantly higher than of the healthy peri‐implant sites. Although not statistically significant, a trend of increase was demonstrated in ICTP PISF samples sampled from peri‐implantitis sites compared with healthy sites. A significant increase was noticed for OC PISF level in peri‐implantitis sites compared with healthy ones. As well as peri‐implant clinical measurements, volumetric changes at PISF may be counted as an important clinical parameter to distinguish the bone destruction sites from healthy sites around oral implants.     

The evaluation of peri‐implant sulcus fluid osteocalcin,osteopontin, and osteonectin levels in peri‐implant diseases

1 Background

Peri‐implant mucositis is an inflammation of the soft tissues surrounding an implant. Peri‐implantitis refers to a process characterized by peri‐implant bone loss along with an inflammation of the soft tissues. Osteocalcin, osteopontin, and osteonectin proteins are related to bone remodeling. The aim of the present study was to investigate peri‐implant sulcus fluid (PISF) osteocalcin, osteopontin, and osteonectin levels in peri‐implant mucositis and peri‐implantitis.

2 Methods

Fifty‐two implants with peri‐implantitis, 46 implants with peri‐implant mucositis, and 47 control implants were included in the study. Clinical parameters including probing depth, modified sulcus bleeding index and modified plaque index were recorded. PISF osteocalcin, osteopontin, and osteonectin levels were analyzed by ELISA kits.

3 Results

There were no significant differences in PISF osteocalcin, osteopontin, and osteonectin total amounts between healthy controls, peri‐implant mucositis and peri‐implantitis groups (P > 0.05). Probing depths were not correlated with PISF osteocalcin, osteopontin, and osteonectin levels in the study groups (P > 0.05).

4 Conclusions

Soft tissue inflammation around dental implants does not cause a change in osteocalcin, osteopontin, and osteonectin levels in PISF. Also, peri‐implantitis does not seem to give rise to an increase in PISF levels of osteocalcin, osteopontin, and osteonectin.     

Analysis of cathepsin-K activity at tooth and dental implant sites and the potential of this enzyme in reflecting alveolar bone loss

Background: Cathepsin‐K is an enzyme involved in bone metabolism which may make this feature important for both natural teeth and dental implants. The aims of the present study are to comparatively analyze the gingival crevicular fluid (GCF)/peri‐implant sulcus fluid (PISF) cathepsin‐K levels of natural teeth and dental implants, and to assess the potential relationship between this biochemical parameter and alveolar bone loss around natural teeth and dental implants. Methods: Probing depth, bleeding on probing, gingival index, and plaque index clinical parameters were assessed, and GCF/PISF samples were obtained from natural teeth/dental implants presenting with either clinical health, gingivitis/peri‐implant mucositis, or chronic periodontitis/peri‐implantitis. Cathepsin‐K activity levels of 42 GCF samples and 54 PISF samples were determined, and marginal bone loss (MBL) measures were calculated from digitalized standardized intraoral periapical radiographs obtained from natural teeth and dental implants by using cemento‐enamel junction and the actual distance between two consecutive threads of the dental implant as reference points for natural teeth and dental implants, respectively. Results: Comparing the natural teeth group with dental implant group with regard to MBL measure, cathepsin‐K activity, and GCF/PISF volume revealed no significant differences. In both natural teeth and dental implant groups, despite higher MBL measures, cathepsin‐K activity, and GCF/PISF volumes with the presence of inflammation, it was the presence of alveolar bone loss that lead to significantly higher values for these parameters. Conclusion: We suggest cathepsin‐K as a biochemical parameter for monitoring periodontal/peri‐implant alveolar bone loss.     

Myeloperoxidase as a measure of polymorphonuclear leukocyte response in inflammatory status around immediately and delayed loaded dental implants: a randomized controlled clinical trial

Background: As well as gingival crevicular fluid (GCF), peri‐implant sulcus fluid (PISF) may have a potential diagnostic value for the early identification of metabolic and destructive processes. Purpose: The aim of this study was to analyze the potential impact of inflammation and loading on PISF myeloperoxidase (MPO) levels, in comparison with GCF. Materials and Methods: A total of 220 sites, dental implant (immediately [IL] or delayed loaded [DL]), and natural tooth, either healthy/noninflamed or gingivitis/inflamed, were classified. Clinical parameters were recorded, and GCF/PISF samples were obtained. GCF/PISF MPO levels were spectrophotometrically determined. Results: Clinical parameters demonstrated increases with the presence of gingival/peri‐implant inflammation. Total MPO levels were higher at inflamed tooth and implant sites compared to noninflamed/healthy sites (p < .05). Although they did not reach a significance level, inflamed IL sites had higher total MPO levels than inflamed DL sites (p = .401). Gingival index and total MPO levels exhibited significant correlations (p < .05). Conclusion: Using implants and natural teeth in the same study design, the findings of the present study support the close relationship between MPO production and inflammation, and may speculate a potential for loading of dental implants, contributing to the MPO content of PISF.     

C‐Telopeptide pyridinoline cross‐links (ICTP( and periodontal pathogens associated with endosseous oral implants

Detection of periodontal or peri‐implant sites exhibiting progressing disease or those at risk of deterioration has proven difficult. Pyridinoline cross‐linked carboxyterminal telopeptide of type I collagen (ICTP), a marker specific for bone degradation found in gingival crevicular fluid (GCF), has been associated with both bone and attachment loss in periodontitis and may be useful for predicting disease activity. The aim of this cross‐sectional study was to examine the relationship between ICTP levels and subgingival species around implants and teeth from 20 partially and 2 fully edentulous patients. GCF and plaque samples were collected from the mesiobuccal site of each implant and tooth. Radioimmunoassay techniques were utilized to determine GCF ICTP levels. Plaque samples were analyzed utilizing checkerboard DNA‐DNA hybridization. Traditional clinical parameters were assessed. Seventy‐one implants and 370 teeth from 22 subjects were examined. ICTP levels and subgingival plaque composition were not significantly different between implants and teeth. Implant sites colonized by Prevotella intermedia, Capnoqtophaga gingivalis, Fusobacterium nucleatum ss vincentii, and Streptococcus gordonii exhibited odds ratios of 12.4, 9.3, 8.1, and 6.7, respectively of detecting ICTP. These results suggest a relationship between elevated ICTP levels at implant sites and some species associated with disease progression. Longitudinal studies are necessary to determine whether elevated ICTP levels may predict the development of per7‐implant bone loss.     

A Cross‐Sectional Assessment of Biomarker Levels Around Implants Versus Natural Teeth in Periodontal Maintenance Patients

Background: Recent studies point to the clinical utility of using peri‐implant sulcular fluid (PISF) as a valuable diagnostic aid for monitoring peri‐implant tissue health. The objectives of this study are to determine the levels of key biomarkers in PISF in periodontal maintenance participants and compare them with their corresponding levels in gingival crevicular fluid (GCF) obtained from the same participants. Methods: PISF and GCF were collected from an implant and a contralateral natural tooth after the clinical examination of 73 participants. The levels of interleukin (IL)‐1α, IL‐1β, IL‐6, IL‐8, IL‐10, IL‐12, IL‐17A, tumor necrosis factor (TNF)‐α, C‐reactive protein, osteoprotegerin, leptin, and adiponectin were determined using multiplex proteomic immunoassays. The correlation of biomarker concentrations between GCF versus PISF, within GCF or PISF, and with several covariates (age, brushing frequency, days since professional cleaning, probing depth [PD], and plaque index) were also determined. Results: Significantly higher levels of IL‐17A (P = 0.02) and TNF‐α (P = 0.03) were noted in PISF when compared with their levels in GCF. Significant positive correlations were noted between the concentrations of cytokines in PISF versus their levels in GCF. Among the covariates, a significant positive correlation was noted between mean PDs around implants and levels of IL‐1β (P <0.05) and IL‐8 (P <0.05) in PISF. Conclusion: The results of this study point to the differential expression of specific biomarkers in GCF versus their levels in PISF in periodontal maintenance patients, which is critical information before establishing PISF as a diagnostic fluid to monitor peri‐implant health.     

C-telopeptide pyridinoline cross-links (ICTP) and periodontal pathogens associated with endosseous oral implants.

Detection of periodontal or peri-implant sites exhibiting progressing disease or those at risk of deterioration has proven difficult. Pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), a marker specific for bone degradation found in gingival crevicular fluid (GCF), has been associated with both bone and attachment loss in periodontitis and may be useful for predicting disease activity. The aim of this cross-sectional study was to examine the relationship between ICTP levels and subgingival species around implants and teeth from 20 partially and 2 fully edentulous patients. GCF and plaque samples were collected from the mesiobuccal site of each implant and tooth. Radioimmunoassay techniques were utilized to determine GCF ICTP levels. Plaque samples were analyzed utilizing checkerboard DNA-DNA hybridization. Traditional clinical parameters were assessed. Seventy-one implants and 370 teeth from 22 subjects were examined. ICTP levels and subgingival plaque composition were not significantly different between implants and teeth. Implant sites colonized by Prevotella intermedia, Capnocytophaga gingivalis, Fusobacterium nucleatum ss vincentii, and Streptococcus gordonii exhibited odds ratios of 12.4, 9.3, 8.1, and 6.7, respectively of detecting ICTP. These results suggest a relationship between elevated ICTP levels at implant sites and some species associated with disease progression. Longitudinal studies are necessary to determine whether elevated ICTP levels may predict the development of peri-implant bone loss.     

Clinical and radiographic peri‐implant parameters and proinflammatory cytokine levels among cigarette smokers,smokeless tobacco users,and nontobacco users

Background

It is postulated that clinical and radiographic peri‐implant parameters are worse and levels of interleukin (IL)‐1β and matrix metalloproteinase (MMP)‐9 in the peri‐implant sulcular fluid (PISF) are higher in cigarette‐smokers (CS) and smokeless‐tobacco users (STU) compared with nontobacco user (NTU).

Purpose

The present study aimed to compare clinical and radiographic peri‐implant inflammatory parameters and levels of IL‐1β and MMP‐9 levels among CS, STU, and NTU.

Materials and Methods

Forty‐five CS (Group‐1), 42 STU (Group‐2), and 44 NTU (Group‐3) were included. Demographic data was collected using a structured baseline questionnaire. Peri‐implant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were recorded and crestal bone loss (CBL) were assessed using standardized digital radiographs. PISF volume and levels of IL‐1β and MMP‐9 in PISF were quantified using enzyme‐linked immunosorbent assay. Clinical peri‐implant parameters and PISF IL‐1β and MMP‐9 concentrations were analyzed with Kruskal‐Wallis test. Bonferroni post hoc adjustment test was used for multiple comparisons. P‐value was set at .05.

Results

Peri‐implant PI and PD were significantly worse in group‐1 and group‐2 patients as compared to group‐3 individuals (P < .05). Peri‐implant CBL was also significantly higher in group‐1 and group‐2 compared with group‐3 (P < .05). Peri‐implant BOP was significantly higher in group‐2 and group‐3 as compared to group‐1 individuals (P < .05). The PISF volume (P < .05) collected and levels of IL‐1β and MMP‐9 were statistically significantly elevated among individuals in group‐1 and group‐2 compared with group‐3 (P < .01). There was no significant difference in PI, PD, CBL, and PISF levels of IL‐1β and MMP‐9 among participants in groups 1 and 2.

Conclusion

Clinical and radiographic peri‐implant parameters were compromised among CS and STU as compared to NTU. Increased expression of local proinflammatory cytokines may explain greater susceptibility of CS and STU to peri‐implant breakdown.     

Analysis of the inflammatory process around endosseous dental implants and natural teeth: myeloperoxidase level and nitric oxide metabolism

PURPOSE: The aim of the present study was to analyze the 2 molecular measures of inflammation: (1) the nitrite, an end metabolite of nitric oxide (NO) oxidation and (2) myeloperoxidase (MPO). Both are found in peri-implant sulcus fluid (PISF) of implants and gingival crevicular fluid (GCF) of natural teeth in healthy or diseased states. MATERIALS AND METHODS: A total of 109 tooth or dental implant sites, either healthy/noninflamed, inflamed (Gingival Index [GI] > 0), or affected by periodontitis, were classified, and GCF/PISF samples were obtained. GCF/PISF MPO and nitrite levels were spectrophotometrically determined. For comparison of clinical parameters and PISF/GCF nitrite and MPO levels, Kruskal-Wallis analysis followed by Mann-Whitney test with Bonferroni correction was performed. Healthy/noninflamed, slightly inflamed, moderate/severely inflamed sites were also analyzed using the Kruskal-Wallis test followed by the Mann-Whitney test with Bonferroni correction. The correlation between nitrite and MPO levels and clinical inflammatory status were analyzed with Spearman's correlation coefficient. RESULTS: Clinical parameters, including both the GCF and PISF volumes, demonstrated gradual increases with the presence of gingival/peri-implant inflammation (P < .05). Despite the higher PISF than GCF volume at healthy sites (P = .001), there were no volumetric differences at inflamed sites (P = .771). PISF from inflamed sites (P = .025) and GCF from gingivitis and periodontitis sites presented higher total MPO levels (P < .05) than samples from noninflamed sites. Despite the relatively stable GCF nitrite levels at healthy and diseased sites, PISF from inflamed sites had higher nitrite content than noninflamed sites (P < .05). CONCLUSIONS: The present study demonstrated the volumetric similarities of PISF and GCF in terms of response to inflammation. However, some differences between the 2 biochemical measures of inflammation and their presence in PISF and GCF were also observed. PISF is likely to have a considerable diagnostic potential for reflecting the biologic changes around load-bearing endosseous dental implants. (Cohort Study) (More than 50 references.)     

种植体周围龈沟液中酶水平的研究

目的 初步探讨种植体修复后第１年内龈沟液（ｇｉｎｇｉｖａｌ ｃｒｅｖｉｃｕｌａｒ ｆｌｕｉｄ,ＧＣＦ）量及其中的天冬氨酸转氨酸（ａｓｐａｒｔａｔｅ ａｍｉｎｏｔｒａｎｓｆｅｒａｓｅ,ＡＳＴ）和碱性磷酸酶（ａｌｋａｌｉｎｅ ｐｈｏｓｐｈａｔａｓｅ,ＡＬＰ）水平的变化,及其与种植体周围为症及骨丧失的关系。方法 以基台连接术后１～１．５个月为基线,修复后３、６、１２个月时分别对１２例患者２６个Ｂｒａｎｅ     

Tenascin-C and matrix metalloproteinase-9 levels in crevicular fluid of teeth and implants

Background: The role of and interaction between bacterial infection and biomechanical impact in the development of peri‐implant inflammatory processes is not clear. Objective: To determine the amount and concentration of tenascin‐C (TNC) in gingival crevicular fluid (GCF) around teeth and in peri‐implant sulcus fluid from healthy implants and implants with peri‐implantitis, and to correlate it with matrix metalloproteinase‐9 (MMP‐9) levels. Materials and Methods: Seven control individuals and 18 patients with 41 implants with/without peri‐implantitis were included. GCF was collected with filter strips and volumes were measured with a Periotron device. The amount of serum albumin per sample was quantified by densitometric analysis of Coomassie‐stained sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Relative activity of MMP‐9 was determined from the densitometry of zymograms. Amounts and concentrations of TNC were evaluated by ELISA. Results: Relative MMP‐9 activity was increased in peri‐implantitis. A tendency was observed to measure higher TNC concentrations at teeth than at implants. The amount of TNC in GCF collected from healthy implant sites and the peri‐implantitis sites was significantly different. Based on immunoblotting, TNC in GCF seemed degraded. In contrast to TNC, MMP‐9 was significantly related to the PD and the volume of GCF. Conclusion: TNC is known to be induced in inflammation. The increase found in peri‐implantitis was less than expected. In the context of peri‐implantitis, TNC might be a marker of bone remodelling rather than inflammation and infection. A possible proteolytic degradation of TNC during peri‐implantitis needs to be studied.     

Calprotectin and cross-linked N-terminal telopeptides in peri-implant and gingival crevicular fluid

In a previous study on guided bone augmentation, a new collagen membrane was compared with an e-PTFE one on 28 partially edentulous patients who received 50 dental implants at stage 2 surgery. After implant integration and subsequent loading, we were able to recruit 22 patients with 22 implants and their contra-lateral corresponding teeth for longitudinal observation. Clinical parameters probing depth (PD), bleeding on probing (BoP), plaque index (PI), assessment of gingival crevicular fluid (GCF) and peri-implant crevicular fluid (PCF) volumes and periapical radiographs were performed at 2- and 3-year control appointments. Calprotectin (MRP 8/14) and cross-linked N-terminal telopeptide (NTx) levels in both crevicular fluids were determined by ELISA. PD was significantly reduced from years 2 to 3 appointments at implant sites as at teeth sites. At the 3-year appointment in both compartments, fluid volumes were significantly increased, which corresponded well with ascending NTx levels. The total amount of calprotectin decreased non-significantly in both GCF and PCF samples. Periapical radiographs revealed stable bone conditions around implants without significant changes from years 2 to 3 examinations. Clinical peri-implant parameters were considered as stable as the periodontal parameters of their corresponding teeth. A parallel increase in NTx levels in both GCF and PCF at 3-year appointment is not clearly understood; it may reflect an upregulation in the overall bone turnover rate.     

Type I collagen carboxyterminal telopeptide in human gingival crevicular fluid in different clinical conditions and after periodontal treatment

Abstract. A total of 126 gingival crevicular fluid (GCF) samples were collected from 20 adults using paper strips. Patients were divided into a periodontitis-affected group (13 subjects) and a periodontitis-free group (7 subjects) by pocket depth and radiological bone loss. 4 subjects from the periodontitis-affected group received a single episode of periodontal treatment (scaling, root planing and curettage) and GCF samples were collected 2, 5, 10, 20 and 40 days after treatment. Type I collagen carfaoxyterminal telopeptide (ICTP) in GCF was extracted into saline solution and determined by a radioimmunological method. Mean GCF ICTP concentration was 425 μg/1 (SEM 45) in periodontitis patients and 148 μg/l (SEM 25) in periodontitis-free subjects, i.e., GCF ICTP concentrations were about 100 × higher than serum reference values. Significant positive correlations were found between GCF ICTP total amount per site and plaque index ( R = 0.362), papilla bleeding index ( R = 0.259), pocket depth ( R = 0.464) and radiological bone loss ( R = 0.418). Periodontal treatment decreased GCF JCTP concentration to the level seen in healthy subjects. However, large variations were seen between subjects and sites. ICTP levels below the detection limit were often found in deep pockets, as well as high values in periodontitis-free subjects. It was concluded that GCF ICTP reflects the local type I collagen degradation in periodontal tissues, and probably gives information about the tissue destruction process beyond the reach of the clinical parameters.     

Crevicular fluid osteocalcin and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) as markers of rapid bone turnover in periodontitis

Abstract The objective of this study was to correlate the levels of 2 putative markers of bone metabolism, namely osteocalcin and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP). to the progression of experimental alveolar bone loss in the beagle dog, 36 control sites and 36 experimental sites in 2 beagle dogs were assessed longitudinally at 2-week intervals for gingival crevicular fluid (GCF) osteocalcin and ICTP levels during a 6-month observation period. Analysis of osteocalcin and ICTP in GCF was performed by RIA. During the study, bone-seeking radiopharmaceutical uptake (BSRU) of ⁹⁹mTc-MDP was assessed monthly; standardized radiographs were taken al 2-week intervals. The results showed osteocalcin and ICTP levels in GCF increased significantly (p<0.05) by 2 weeks following initiation of disease. This increase preceded significant increases in BSRU by 2 weeks and radiographic evidence of bone loss by 4 weeks, BSRU was significantly elevated (p<0.05) at experimental sites as compared to controls at 4 and 8 weeks post-disease initiation. Osteocalcin in GCF peaked 8 and 10 weeks after ligature placement in experimental sites at levels nearly 10-fold greater than contralateral paired control sites. ICTP levels in GCF remained elevated throughout the entire disease progression phase. Following the removal of ligatures, both GCF ostocalcin and ICTP levels dropped precipitously approaching control values. Osteocalcin revealed overall a positive predictive value (PPV) and negative predictive value (NPV) for future bone loss during disease progression of 0.87 and 0.34. respectively, while ICTP showed both high PPV and NPV of 0.87 and 0.91 respectively. Results from this study in the dog model indicate that osteocalcin and especially ICTP relate to indices of active periodontal bony destruction and suggest that these molecules may serve as predictive markers for future alveolar bone loss.     

Glycosaminoglycans in peri-implant sulcus fluid from implants placed in sinus-inlay bone grafts

Abstract: Glycosaminoglycans (GAG) present in peri‐implant sulcus fluid (PISF) were used as an indicator of the metabolic activity in the supporting tissues of implants placed in maxillary bone or maxillary bone and bone grafts together. The study included 16 patients who received implants (Brånemark system^®) and sinus‐inlay bone grafts. In 12 of these patients, the implants were placed in either maxillary bone alone or maxillary bone and sinus‐inlay bone grafts in combination. Altogether the patients received a total of 102 implants, of which 73 implants were placed in bone grafts and 29 implants in maxillary bone alone. Samples of PISF were tested at 2–8 days and at 6 months after abutment connection. Levels of the GAG’s chondroitin‐4‐sulphate (C4S) and hyaluronan (HA) were assessed using cellulose acetate electrophoresis and densitometric scanning of Alcian blue‐stained strips against known GAG standards. The C4S was used as a bone metabolic marker, and HA was used to reflect the progress of soft tissue healing. Comparing grafted and non‐grafted regions, there was no significant difference in either C4S levels or HA levels during the first 8 days or at the 6 months period. The levels of HA from the first week collection did not differ significantly from the HA level after 6 months in either type of bone. However, the level of C4S was significantly lower after 6 months than during the first week, in both maxillary and grafted bone but consistent with a normal metabolic turnover. C4S can therefore be used as an indicator of the progressive healing of bone adjacent to implants.     

Nitric oxide and arginase levels in peri-implant tissues after delayed loading

ObjectiveNitric oxide (NO) is synthesized from the conversion of L-arginine to L-citrulline by NO synthase (NOS). Arginase can compete with NOS for the common substrate L-arginine, and thus inhibit NO production. NO levels and arginase ezyme might affect the bone remodeling cycle around implants. The aim of this studywas to investigate NO and arginase levels in gingival crevicular fluid (GCF), peri-implant sulcular fluid (PISF), and saliva.Materials and methodsTwenty patients with one or more implants (Straumann^®; Institute Straumann AG, Basel, Switzerland) restored with fixed crown prostheses were included in the study. Plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing (BOP) were recorded from six sites of each tooth and implant at baseline and at months 1, 3, and 6 after loading. The saliva, GCF, and PISF were collected at baseline and at months 1, 3, and 6 after loading. NO level and arginase enzyme were evaluated in GCF, PISF, and saliva.ResultsArginase and NO levels in saliva did not change significantly from baseline to months 1, 3, and 6. However, both PISF NO and arginase levels showed an increased pattern from baseline to month 6. NO levels were significantly higher at months 3 and 6, compared to baseline, while PISF arginase levels increased significantly from baseline to months 3 and 6.ConclusionNO and arginase enzyme measurements in saliva, GCF, and PISF may be beneficial in the determination of current peri-implant tissues. In particular, PISF might provide more information than saliva.     

Immediate non-occlusal vs. early loading of dental implants in partially edentulous patients: a multicentre randomized clinical trial. Peri-implant bone and soft-tissue levels

Objectives: To compare peri‐implant bone and soft‐tissue levels of immediately non‐occlusally loaded vs. non‐submerged early loaded implants in partially edentulous patients up to 14 months after placement. Material and methods: Fifty‐two patients were randomized in five Italian private practices: 25 in the immediately loaded group and 27 in the early loaded group. To be immediately loaded, single implants had to be inserted with a torque of ≥30 N cm, and splinted implants with a torque of ≥20 N cm. Immediately loaded implants were provided with non‐occluding temporary restorations within 48 h. After 2 months, the provisional restorations were placed in full occlusion. Implants were early loaded after 2 months. Final restorations were provided 8 months after placement. Blinded assessors evaluated peri‐implant bone and soft‐tissue levels. Results: Fifty‐two implants were immediately loaded and 52 were early loaded. No drop‐out occurred. One single immediately loaded implant failed 2 months after placement. Both groups gradually lost peri‐implant bone in a highly statistically significant manner at 2, 8, and 14 months. After 14 months, patients of both groups lost an average of 1.1 mm of peri‐implant bone. There were no statistically significant differences between the two loading strategies for peri‐implant bone and soft‐tissue level changes (P>0.05). After 14 months, the position of the soft tissues did not change significantly from baseline (delivery of the final restorations 8 months after placement). Conclusions: There were no statistically or clinically significant differences between immediate and early loading of dental implants with regard to peri‐implant bone and soft‐tissue levels as evaluated in the present study.     

Subantimicrobial-dose doxycycline modulates gingival crevicular fluid biomarkers of periodontitis in postmenopausal osteopenic women

BACKGROUND: We recently demonstrated that a 2-year subantimicrobial-dose doxycycline (SDD) regimen (double-masked, placebo-controlled clinical trial) in postmenopausal (PM) women exhibiting mild systemic bone loss (osteopenia) and local bone loss (periodontitis) reduced the progression of periodontal attachment loss (intent-to-treat analysis) and the severity of gingival inflammation and alveolar bone loss (subgroups) without producing antibiotic side effects. We now describe SDD effects on biomarkers of collagen degradation and bone resorption in the gingival crevicular fluid (GCF) of the same vulnerable subjects. METHODS: GCF was collected from SDD- and placebo-treated PM subjects (n=64 each) at the baseline and 1- and 2-year appointments; the volume was determined; and the samples were analyzed for collagenase activity (using a synthetic peptide as substrate), relative levels of three genetically distinct collagenases (Western blot), a type-1 collagen breakdown product/bone resorption marker (a carboxyterminal telopeptide cross-link fragment of type I collagen [ICTP]; radioimmunoassay), and interleukin-1beta (enzyme-linked immunosorbent assay). Statistical analyses were performed using generalized estimating equations; primary analyses were intent-to-treat. RESULTS: Collagenase activity was significantly reduced by SDD treatment relative to placebo based on intent-to-treat (P=0.01). ICTP showed a similar pattern of change during SDD treatment, and GCF collagenase activity and ICTP were positively correlated at all time periods (P<0.001). Matrix metalloproteinase (MMP)-8 accounted for approximately 80% of total collagenase in GCF, with much less MMP-1 and -13, and SDD reduced the odds of elevated MMP-8 by 60% compared to placebo (P=0.006). CONCLUSION: These observations support the therapeutic potential of long-term SDD therapy to reduce periodontal collagen breakdown and alveolar bone resorption in PM women; effects on serum biomarkers of systemic bone loss in these subjects are being analyzed.     

Five‐year outcomes of a randomized clinical trial comparing bone‐level implants with either submerged or transmucosal healing

Aim

To evaluate the long‐term hard and soft tissue peri‐implant tissue stability of bone‐level implants using a different implant placement protocol (submerged versus transmucosal).

Materials and methods

This study was partly a subset analysis of a multicentre study where in 40 patients, a single bone‐level implant with platform switching and a conical implant‐abutment interface was placed either submerged or transmucosal in non‐molar sites. Changes in the peri‐implant tissues between implant placement and 5 years were assessed clinically and radiologically. Patient‐related outcomes were also recorded.

Results

Thirty patients completed the 5‐year follow‐up. Implant survival rate was 100%. The mean radiographic changes in crestal bone levels between baseline and 5 years were 0.59 (0.92) mm and 0.78 (1.03) mm for the submerged and the transmucosal groups, respectively. No statistical significant differences were found between the groups for any of the investigated variables. Peri‐implantitis, defined as changes in the level of crestal bone of ≥2 mm together with bleeding on probing, was only diagnosed in one patient. Patients in both groups were highly satisfied with the treatment received.

Conclusions

Bone‐level implants with submerged or transmucosal healing protocols demonstrated similar outcomes after 5 years. Both protocols yielded optimal clinical and radiographic results when bone‐level implants were placed in non‐molar positions for single tooth replacement.     

Collagenase, gelatinase and elastase activities in sulcular fluid of osseointegrated implants and natural teeth

Abstract Proteinases play a key rôle in the physiological degradation and remodelling of the periodontal tissues. The rôle of these enzymes in tissue remodelling in connection with the insertion of dental endosseous implants has not been elucidated. Therefore, the aim of the present study was to identify the eventual presence of collagenase, gelatinase and elastase activities in periimplant sulcus fluid (PTSF) of osseointegrated implants. Gelatinolytic activity in the samples was studied with gelatin-zymograms. Collagenase activity and its susceptibility to tetracycline-inhibition were monitored with SDS-polyacrylamide gel electrophoresis and laser densitometry, and elastase activity with synthetic substrate. Low activities of elastase and collagenase were detected in both PISF of osseointegrated implant patients and gingival crevicular fluid (GCF) of the control patients whereas significantly higher activities were delected in GCF of adult periodontitis patients. Also the profiles of gelatinases were similar in PISF of osseointegrated implant patients and GCF of the controls, but differed from the profile of active gelatinases present in GCF of adult periodontitis patients. The similar activities/characteristics of these proteinases in both periimplant sulcus fluid of healthy dental implants and GCF of healthy natural teeth suggest that they comprise the major proteinases for both periodontal and periimplant tissue remodelling or destruction.