Surface Topography Has Less Influence on Peri-Implantitis than Patient Factors: A Comparative Clinical Study of Two Dental Implant Systems

OBJECTIVES

This study aims to assess the risk of peri-implantitis (PI) onset among different implant systems and evaluate the severity of the disease from a population of patients treated in a university clinic. Furthermore, this study intends to thoroughly examine the surface properties of the implant systems that have been identified and investigated.

MATERIAL AND METHODS

Data from a total of six hundred and 14 patients were extracted from the Institute of Clinical Dentistry, Dental Faculty, University of Oslo. Subject- and implant-based variables were collected, including the type of implant, date of implant installation, medical records, recall appointments up to 2022, periodontal measurements, information on diabetes, smoking status, sex, and age. The outcome of interest was the diagnosis of PI, defined as the occurrence of bleeding on probing (BoP), peri-implant probing depth (PD) ≥ 5 mm, and bone loss (BL). Data were analyzed using multivariate linear and logistic regression. Scanning electron microscopy, light laser profilometer, and X-ray photoelectron spectroscopy were utilized for surface and chemical analyses.

RESULTS

Among the patients evaluated, 6.8% were diagnosed with PI. A comparison was made between two different implant systems: Dentsply Sirona, OsseospeedTM and Straumann SLActive, with mean follow-up times of 3.84 years (SE: 0.15) and 3.34 years (SE: 0.15), respectively. The surfaces have different topographies and surface chemistry. However, no significant association was found between PI and implant surface/system, including no difference in the onset or severity of the disease. Nonetheless, plaque control was associated with an increased risk of developing PI, along with the gender of the patient. Furthermore, patients suffering from PI exhibited increased BL in the anterior region.

CONCLUSION

No differences were observed among the evaluated implant systems, although the surfaces have different topography and chemistry. Factors that affected the risk of developing PI were plaque index and male gender. The severity of BL in patients with PI was more pronounced in the anterior region. Consequently, our findings show that success in implantology is less contingent on selecting implant systems and more on a better understanding of patient-specific risk factors, as well as on implementing biomaterials that can more effectively debride dental implants.

Non-invasive sampling procedure revealing the molecular events at different abutments of bone-anchored hearing systems–A prospective clinical pilot study

Purpose

To investigate the molecular activities in different compartments around the bone-anchored hearing system (BAHS) with either electropolished or machined abutments and to correlate these activities with clinical and microbiological findings.

Materials and methods

Twelve patients received machined or electropolished abutments after implant installation of BAHS. Peri-abutment fluid and tissue were collected from baseline to 12 months. Gene expression of cytokines and factors related to tissue healing and inflammation, regeneration and remodelling, as well as bacterial recognition were determined using quantitative-polymerase chain reaction (qPCR). The clinical status was evaluated using the Holgers scoring system, and bacterial colonisation was investigated by culturing.

Results

The gene expression of inflammatory cytokines (IL-8, IL-1β, and IL-10) and bacteria-related Toll-like receptors (2 and 4) was higher in the peri-abutment fluid than at baseline and in the peri-abutment tissue at 3 and 12 months. Conversely, the expression of genes related to tissue regeneration (Coll1a1 and FOXO1) was higher in the tissue samples than in the peri-abutment fluid at 3 and 12 months. Electropolished abutments triggered higher expression of inflammatory cytokines (IL-8 and IL-1β) (in peri-abutment fluid) and regeneration factor FOXO1 (in peri-abutment tissue) than machined abutments. Several cytokine genes in the peri-abutment fluid correlated positively with the detection of aerobes, anaerobes and Staphylococcus species, as well as with high Holger scores.

Conclusion

This study provides unprecedented molecular information on the biological processes of BAHS. Despite being apparently healed, the peri-abutment fluid harbours prolonged inflammatory activity in conjunction with the presence of different bacterial species. An electropolished abutment surface appears to be associated with stronger proinflammatory activity than that with a machined surface. The analysis of the peri-abutment fluid deserves further verification as a non-invasive sampling and diagnostic procedure of BAHS.

Comparison of Crestal Bone Loss and Osteocalcin Release Kinetics in Immediately and Delayed Loaded Implants: A Randomised Controlled Trial

PURPOSE

To compare concentration and release kinetics of osteocalcin and crestal bone loss under immediate and delayed loading conditions during osseointegration.

MATERIALS AND METHODS

Forty-one patients who were indicated for rehabilitation with dental implants randomly received either implant with placement of permanent prosthesis after 3 months (delayed loading) or implant with placement of permanent prosthesis within 7 days (immediate loading). Radiographic assessment of crestal bone loss at the mesial and distal surface was done at 3, 6 and 12 months after implant placement. Peri-implant sulcular fluid was collected immediately from the buccal surface at two sites after implant insertion and also, at 7, 15, 30 and 90 days after surgery. The level of osteocalcin was evaluated using ELISA and data were compared using two sample t-test. Differences between two groups were analyzed by unpaired Student's t test. Intragroup comparison was done by repeated measures ANOVA.

RESULTS

Mean crestal bone loss was lower in the immediate loading group compared to the delayed loading group at 3, 6 and 12 months (P < 0.001). Intragroup comparison revealed a statistically significant increase in osteocalcin levels in both group I (F = 26712.2) and group II (F = 10497.2) at the predetermined time intervals CONCLUSIONS: Lesser crestal bone loss and early release of osteocalcin was found in the immediately loaded condition than in the delayed loaded condition. The study substantiates that immediately loaded implants shows less crestal bone as well as early release of osteocalcin facilitating upregulation of bone metabolism, improving long term health of bone and prognosis of implants. Immediately loaded implants can be a better treatment protocol provided there is adequate bone and primary stability. This article is protected by copyright. All rights reserved.

Dental Implants in Patients with Oral Lichen Planus: A Systematic Review

Background and Objectives: To integrate the available published data on patients with oral lichen planus (OLP) rehabilitated with dental implants, as well as to review the recommendations for OLP patients receiving implants. Materials and Methods: An electronic search was undertaken in February 2019 using five databases. Publications reporting cases of patients with OLP and rehabilitated with implant-supported oral prosthesis were included. Results: Twenty-two publications were included (230 patients, 615 implants). The overall implant failure rate was 13.9% (85/610). In patients with oral squamous cell carcinoma (OSCC) the failure rate was 90.6% (29/32), but none of these implants lost osseointegration; instead, the implants were removed together with the tumor. One study presented a very high implant failure rate, 76.4% (42/55), in patients with “active lichen planus”, with all implants failing between 7–16 weeks after implant placement, and its conflicting and incongruent results are discussed in detail. There was a statistically significant difference between the failure rates in implants installed in different jaws (maxilla/mandible) and when implants of different surfaces were used (turned/moderately rough), but not between patients with reticular or erosive OLP types, or between male and female patients. If OSCC patients and the cases of the latter study are not considered, then the failure rate becomes very low (2.7%, 14/523). The time between implant placement and failure was 25.4 ± 32.6 months (range 1–112). The mean ± SD follow-up was 58.9 ± 26.7 months (1–180). Conclusions: When the results of the one study with a very high failure rate and of the cases that developed OSCC are not considered, the dental implant failure rate in OLP patients was 2.7% after a follow-up of approximately five years. Recommendations are given when treating OLP patients with dental implants.

Dental implant surfaces treated with phosphoric acid can modulate cytokine production by blood MN cells

The study characterizes dental implant surfaces treated with phosphoric acid to assess the effects of acid treatment on blood cells and correlate them with cytokine levels. The implant surfaces examined were divided into untreated metal surface (US; n = 50), metal surface treated with phosphoric acid (ATS; n = 50) and cement surface (CS; n = 50) groups. The samples were characterized by scanning electron microscopy (SEM) and rheometry. The implants were incubated with human blood mononuclear cells for 24 h, with surface rinsing in the ATS treatment. Cell viability was determined by colorimetric methods and cytokines in the culture supernatant were quantified using flow cytometry. In the ATS group, the surface porosity and contact surface were increased and plaques were observed on the surface. The blood flow and viscosity curves were similar among the treatments, and the high cell viability rates indicate the biocompatibility of the materials used. An increase in the levels of IL-2, IL-4, IL-6, IL-10 and TNF-α was observed in the ATS and CS groups. There were positive correlations between IL-10 and IL-2 levels and between IL-10 and IL-4 levels in the culture supernatant of the ATS group. The results suggest that implant surface treatment with phosphoric acid activates the production of inflammatory cytokines. The increased cytokine levels can modulate the immune response, thereby improving biofunctional processes and promoting the success of dental implants.

Mapping of inflammatory biomarkers in the peri-implant crevicular fluid before and after the occlusal loading of narrow diameter implants

OBJECTIVE

To monitor the cytokine release patterns in the peri-implant crevicular fluid (PICF) and to investigate which factors affect the success rate of narrow diameter implants (NDI) during the first year.

MATERIAL AND METHODS

Mandibular implant overdentures (IOD) retained by 2 NDI were installed in 16 clinically atrophic edentulous patients. The following parameters were monitored during the first year: (i) peri-implant health parameters (plaque index (PI), calculus presence (CP), gingival index (GI), probing depth (PD) and bleeding on probing (BoP); (ii) cytokine concentrations in the PICF (TNF-α, IL-1β, IL-6, IL-10); (iii) implant stability quotient (ISQ); (iv) marginal bone level (MBL) and bone level change (BLC); (v) implant success. The insertion torque, bone type, mandibular atrophy, time since edentulism, and smoking habits were also recorded. All data were analyzed using multivariable multilevel mixed-effects regression models.

RESULTS

The variability in the TNF-α release patterns temporarily reduced at weeks (w) 8-12, while the IL-1β concentrations remained low until they peaked at w48 [p < 0.05; + 177.55 pg/μl (+ 96.13 - + 258.97)]. Conversely, IL-10 release decreased significantly at w48 [p < 0.05; - 456.24 pg/μl (- 644.41 - - 268.07)]. The PD and ISQ decreased significantly (p < 0.05) over the follow-up period, while the MBL was stable after w48 with a BLC of 0.12 ± 0.71 mm. The overall success rate was 81.3%, and was influenced by TNF-α, IL-1β, IL-10, PI, GI, PD, smoking, and time since edentulism.

CONCLUSION

Pro- and anti-inflammatory cytokine release was balanced during the first 24 weeks. The GI, smoking, and time since edentulism are the most important factors determining the implant success.

CLINICAL RELEVANCE

The study contributes to the understanding of the osseointegration process in a clinically atrophic population rehabilitated with IOD, and highlights the importance of monitoring clinical peri-implant health-related parameters, smoking habit, and time since edentulism to predict implant success rates.

Changes in proinflammatory gene expression in human whole blood after contact with UV-conditioned implant surfaces

OBJECTIVES

The aim of this in vitro study was to assess changes in the gene expression of proinflammatory cytokines in human whole blood after contact with titanium implant surfaces conditioned by UV light. To this end, expression levels of proinflammatory cytokines were analyzed in vitro in human whole blood.

MATERIALS AND METHODS

Dental implants made of grade 4 titanium were conditioned by UV light in a UV device and submerged in human whole blood. Unconditioned implants served as controls, and blood samples without implants served as the negative control group. Sampling was performed at 1, 8, and 24 h. Changes in the expression levels of interleukin-1β (IL1B) and tumor necrosis factor alpha (TNF) were assessed using RT-qPCR at the mRNA level.

RESULTS

The gene expression of IL1B was significantly suppressed in the test group over the observation period compared to the control group during the 1-8 h after having contact between the implant surface and the blood. The gene expression of TNF was not significantly altered by UV conditioning after 1 and 8 h of observation, but both cytokine expression levels were increased significantly after 24 h.

CONCLUSIONS

Differences in the gene expression of proinflammatory cytokines after insertion of UV-conditioned titanium implants can be assessed using a human whole blood test. UV-conditioned implant surfaces apparently suppress the release of IL1B in vitro.

CLINICAL RELEVANCE

The results of our publication demonstrate that modulation of the early inflammatory response in human whole blood is possible by surface treatment with UV light. In particular, the suppression of IL1B expression, especially after the initial contact of blood cells, may be beneficial in the osseointegration of titanium implants by positively influence the balance between rejection and acceptance of an implant.

Novel in vitro comparative model of osteogenic and inflammatory cell response to dental implants

OBJECTIVES

Roughened dental implants promote mesenchymal stem cell (MSCs) osteoblastic differentiation, and hydrophilic modifications induce anti-inflammatory macrophages activation. While the effect of different surface modifications on osseointegration of commercial dental implants have been compared in vivo and clinically, the initial cellular response to these modifications often overlooked. We aimed to characterize the macrophage inflammatory response and MSC osteogenesis across different commercially available implants in vitro.

METHODS

Six commercially available rough implants [OsseoSpeed™ (Astra-Tech™, Implant A); Osseotite^® (Biomet 3i™, Implant B); TiUnite™ (Nobel-Biocare^®, Implant C); Ti-SLA^®, (Implant D), Roxolid^® (RXD-SLA, Implant E), RXD-SLActive^® (Implant F) (Straumann^®)] were examined. Macrophages and MSCs were seeded directly on implants and cultured in custom vials. mRNA and protein levels of pro- (IL1B, IL6, IL17A, CXCL10, TNFa) and anti- (IL4, IL10, TGFB1) inflammatory markers were measured after 24 and 48h in macrophages. Osteoblastic differentiation of MSCs was assessed after seven days by alkaline phosphatase activity, osteocalcin, and angiogenic, osteogenic, and inflammatory markers by ELISA and qPCR (n=6/variable, ANOVA, post hoc Tukey HSD with α=0.05).

RESULTS

Hydrophilic implant F induced the highest level of osteogenic factor released from MSCs and anti-inflammatory factors from macrophages with the lowest level of pro-inflammatory factors. Alternatively, implants A and C supported lower levels of osteogenesis and increased secretion of pro-inflammatory factors.

SIGNIFICANCE

In this study, we successfully evaluated differences in cell response to commercially available clinical implants using an in vitro model. Data from this model suggest that not all surface modification procedures generate the same cell response.

Oral microbiome and peri-implant diseases: where are we now?

Peri-implant infective diseases (PIIDs) in oral implantology are commonly known as peri-implant mucositis (PIM) and periimplantitis (PI). While PIM is restricted to the peri-implant mucosa and is reversible, PI also affects implant-supporting bone and, therefore, is very difficult to eradicate. PIIDs in clinical outcome may resemble gingivitis and periodontitis, as they share similar risk factors. However, recent study in the field of proteomics and other molecular studies indicate that PIIDs exhibit significant differences when compared to periodontal diseases. This review aims to elucidate the current knowledge of PIIDs, their etiopathology and diversified microbiology as well as the role of molecular studies, which may be a key to personalized diagnostic and treatment protocols of peri-implant infections in the near future.

Comparison between inflammation-related markers in peri-implant crevicular fluid and clinical parameters during osseointegration in edentulous jaws

OBJECTIVES

The aim of this study is to improve the understanding of interleukin mechanisms during osseointegration to enhance the monitoring of implant failure and success. Clinical parameters, implant stability, and cytokine levels in peri-implant crevicular fluid (PICF) during early bone healing after implant placement were investigated.

MATERIAL AND METHODS

Sixty narrow implants were placed in mandible anterior region of 30 edentulous patients (67.23 ± 7.66 years). Bone type, insertion torque, and primary stability were registered during surgery. Clinical measurements of peri-implant health and the secondary implant stability quotient (ISQ) were recorded. Samples from the PICF were collected 1, 2, 4, 8, and 12 weeks after surgery and analyzed for IL-1β, IL-6, IL-10, and TNF-α levels using ELISAs.

RESULTS

The gingival index increased significantly during the first week (p = 0.05), while the plaque index increased significantly between 4 to 8 and 8 to 12 weeks (p < 0.05). The probing depth and the ISQ also reduced significantly (p < 0.05) over time. The TNF-α release increased significantly after the 2nd week for non-atrophic patients and 4th week for atrophic patients (p < 0.05). The IL-1β concentrations showed a short-lived peak after 1st week (p = 0.003), specially in atrophic patients and sites with bone type I (p = 0.034; p = 0.007). The IL-6 concentrations peaked during the 1st and 2nd weeks (p < 0.05; p = 0.005) in atrophic patients and in bone type II (p = 0.023; p = 0.003). The IL-10 concentrations increased gradually over time, showing the highest concentrations at the 12th week (p < 0.005). A total of 12 implants failed at different periods.

CONCLUSION

While the clinical measurements presented differences between the evaluation periods, these were not indicative of early dental implant failure or peri-implant diseases. Smoking, bone atrophy, and bone type can greatly influence the cytokines concentrations during the healing time.

Wound healing protein profiles in the postoperative exudate of bisphosphonate-related osteonecrosis of mandible

Recurrent bacterial infections in cases of bisphosphonate-related osteonecrosis of jaw (BRONJ) frequently occur. Therefore, BRONJ are usually treated by radical saucerization followed by intensive antibiotic medications without bisphosphonate therapy. The postoperative exudate (POE) from BRONJ lesions may directly indicate the inflammatory status of osteomyelitis in patients, but so far, the POE has rarely been examined for its expression of various cytokines and wound healing proteins. A total of 27 cases of BRONJ, which involved the mandible, were selected and their individual POE collected 6 h, 1 day, and 2 days after surgical intervention was analyzed by immunoprecipitation high performance liquid chromatography (IP-HPLC). The different protein expressions in the BRONJ POE were compared with findings from ten cases of chronic mandibular osteomyelitis (CMO) exudate as the control group. For the protein expressions for inflammation, osteogenesis, and angiogenesis, in the 6 h POE sample, the BRONJ exudate exhibited more expression of IL-10, IL-28, OPG, and osteocalcin, but less expression of TNFα and LL-37 than the control. In the 1 day POE sample, the BRONJ exudate showed more expression of TNFα, IL-6, 8, 12, 28, α1-antitrypsin, VEGF-A, and VEGF-C, but less expression of CD68, lysozyme, bFGF, RANKL, bFGF, and ALP than the control. In the 2 day POE sample, the BRONJ exudate consistently showed more expression of LL-37, β-defensin-1, and VEGF-A than the control. The present BRONJ POE revealed the rapid progress of bony wound healing through increased molecular signaling for inflammation, angiogenesis, and osteogenesis compared to the control. Therefore, it was suggested that the POE obtained from the postoperative bony lesions should be collected and analyzed by the IP-HPLC method to predict the prognosis of seriously complicated inflammatory bony diseases such as BRONJ.

Relation between the stability of dental implants and two biological markers during the healing period: a prospective clinical study

OBJECTIVES

The purposes of this study were to examine the correlation between the stability of dental implants and bone formation markers during the healing period and to monitor the stability of dental implants using the resonance frequency analysis (RFA) method. The null hypothesis of the study is no correlation between the stability of dental implant and bone formation markers.

METHODS

The study is a prospective clinical study during the 3-month healing period of implant. At implant placement (PW Plus, Nakhon Pathom, Thailand) and after 1, 2, 3, 4, 6, 8, 10, and 12 weeks, RFA assessments were performed and gingival (GCF)/peri-implant crevicular fluids (PICF) were collected from ten patients. The level of osteocalcin (OC) was measured by using ELISA kits, and the level of alkaline phosphatase (ALP) activity was measured by colorimetric analysis. Repeated measures analysis of variance, the Friedman test, the Mann-Whitney U test, and the Pearson correlation were performed for data analysis.

RESULTS

There was a statistical decrease in the mean implant stability quotient (ISQ) values between 1 and 3 weeks (P < 0.05). The ISQ values recovered to the initial values at 4 weeks. There was no statistical difference in the ALP level at each measurement, while there was a statistical increase in the OC level at 6, 8, 10, and 12 weeks when compared with 1 week (P < 0.05). There was a significant correlation between ALP levels and ISQ values (r = 0.226, P < 0.05). There was a statistically significant correlation between OC levels and ISQ values at 1-12 weeks (r = 0.245, P < 0.05).

CONCLUSIONS

The ISQ values were weakly correlated with both ALP and OC. The three-thread-design implant showed a high stability through healing period.