Changes in the surface topography and element proportion of clinically failed SLA implants after in vitro debridement by different methods

Combining Glycine Powder Air-Polishing and Ultrasonic Scaling for Bone Regeneration Around Infected Dental Implants

OBJECTIVES

In vitro studies were conducted to evaluate the effectiveness of combining glycine powder air-polishing (AP) and ultrasonic scaling (US) in surgical bone reconstructive therapy for peri-implantitis.

MATERIALS AND METHODS

Twenty clinically failed implants and 60 pristine implants were treated in vitro with AP and/or US by using stainless steel, titanium, or carbon fiber tips. Implant surface topography, contaminant distribution, elemental proportion, and composition were analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy.

RESULTS

AP effectively removed bacterial plaques but was unable to eliminate calcified deposits involving calculi and bone fragments. Conversely, US exhibited a high capacity for removing calcified deposits but inevitably altered implant surface topography and the atomic percentages of oxygen (O) and titanium (Ti) regardless of the ultrasonic tip used. AP showed minimal effects on the implant surface and even alleviated the adverse effects of US on the surface topography and the atomic percentages of O, Ti, and even carbon. A sequential protocol involving AP followed by US, with a final AP step, effectively removed contaminants from infected implants while minimally affecting the original surface features.

CONCLUSIONS

The combined application of AP and US in surgical peri-implantitis therapy may be a preferred and effective approach for obtaining bone regeneration around infected dental implants.

Periodontal Endoscopy for Mechanical Debridement in the Non-Surgical Management of Peri-Implantitis: A Narrative Review

Background: The aim of the present narrative review is to synthesize the available scientific evidence on the effects of submarginal instrumentation with periodontal endoscopy and evaluate its' potential efficacy in terms of the non-surgical therapy of peri-implantitis. Methods: The literature search was performed via electronic databases, including PubMed, Web of Science, Cochrane, and Scopus, and was supplemented by manual searching. A literature review was conducted addressing the following PICOS questions: (1) What is the efficacy of non-surgical submarginal instrumentation of the implant surface with the aid of a periodontal endoscope in patients with peri-implantitis? (2) What is the efficacy of non-surgical subgingival instrumentation performed with the aid of a periodontal endoscope compared with conventional subgingival instrumentation in patients with periodontitis, in terms of clinical parameters and patient-reported outcomes? Mechanical decontamination of the implant surface is crucial for resolving inflammation and arresting further bone loss. However, there is no consensus on the most effective treatment. Non-surgical therapy remains the initial intervention, focused on biofilm removal to control the disease, although with limited capability to achieve complete disease resolution as the presence of threads and the complex-structured implant surface hinder effective biofilm removal. This evokes the need for providing supporting technologies such as periodontal endoscopy, which enables direct visualization and precision, potentially enhancing the outcomes and reducing the necessity for surgical procedures and their associated risks. Within the limitations of this narrative review, periodontal endoscopy may offer a less tissue-invasive approach. Larger prospective studies and RCTs are needed to confirm these findings and guide clinicians in determining periodontal endoscopy's suitability based on specific case characteristics.

The Decontamination Effect of an Oscillating Chitosan Brush Compared With an Ultrasonic PEEK-Tip: An In Vitro Study Using a Dynamic Biofilm Model

OBJECTIVES

This study aimed to assess the effect of an oscillating chitosan brush (OCB) compared with an ultrasonic device with PEEK tip (US-PEEK) for mechanical implant surface decontamination using an in vitro model combining 3D models and a validated dynamic multispecies biofilm.

MATERIALS AND METHODS

A multispecies biofilm using six bacterial strains (Streptococcus oralis, Veillonella parvula, Actinomyces naeslundii, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans) was seeded on dental implants with machined and sandblasted, large-grit and acid-etched (SLA) surfaces. These were installed in 3D models depicting peri-implant defect. Mechanical decontamination was performed for 120 s using either an OCB or a US-PEEK. A negative control group received no treatment. Scanning electron microscopy (SEM) was used to evaluate the bacterial composition and quantitative PCR (qPCR) analyzed the number of each bacterial species [colony-forming units per milliliter (CFU/mL)].

RESULTS

Well-structured biofilms with a dense microbial distribution were observed on the negative control implants after 72 h. qPCR following mechanical decontamination showed a scarce bacterial reduction in the OCB group. The US-PEEK group exhibited a significant decrease in bacterial species compared to both OCB and control groups (p < 0.05). A biofilm removal effect was also observed in the OCB group for the machined implant surfaces.

CONCLUSION

In vitro assessment using an anatomical 3D model showed that mechanical decontamination effectively reduced biofilm. The US-PEEK group demonstrated biofilm reduction on the SLA surface, while the OCB group showed a reduction on the machined implant surface. Additionally, the US-PEEK group demonstrated greater efficacy in reducing bacterial numbers.

The biofilm removal effect and osteogenic potential on the titanium surface by electrolytic cleaning: An in vitro comparison of electrolytic parameters and five techniques

OBJECTIVES

To determine the optimal current and time of electrolytic cleaning (EC), compare its biofilm removal effect with generic treatments and evaluate the influence of EC to surface characteristics and osteogenic potential of SLA titanium (Ti) discs.

MATERIALS AND METHODS

The six-species biofilm-covered Ti discs were placed as cathodes in physiologic saline and subjected to various current and time treatments. The residual biofilms were evaluated to determine the optimal parameters. The contaminated Ti discs were randomized and treated by rotating Ti brush; ultrasonic-scaling with metal tips; ultrasonic-scaling with PEEK tips; air-polishing and EC. The residual biofilms were compared using a lipopolysaccharide kit (LPS), scanning electron microscope (SEM), confocal laser scanning microscopy and colony-forming unit counting. Non-contaminated Ti discs were treated and characterized. The bone marrow mesenchymal stem cells (BMSCs) were cultured on treated non-contaminated Ti discs. The adhesion, proliferation, alkaline phosphatase (ALP) activity and osteocalcin level of BMSCs were assessed.

RESULTS

The parameters at 0.6A5min were considered optimal. For LPS and SEM, EC promoted a significantly greater biofilm removal than the other groups. There were no changes in the Ti discs' colour, topography, roughness and chemical elements after EC, and the electrolysis-treated Ti discs obtained a super-hydrophilic surface. EC positively impacted the proliferation and ALP activity of BMSCs, surpassing the efficacy of alternative treatments.

CONCLUSIONS

EC achieves a near-complete eradication of contaminants on the SLA surface, causes no surface damage with improved hydrophilicity, and promotes the early osteogenic response of BMSCs, which makes it a promising treatment for peri-implantitis.

Effect of Low-Level Laser Irradiation (810 nm) on the Proliferation and Differentiation of Osteoblast-Like Cells Cultured on SLA Titanium Discs Exposed to a Peri-implantitis Environment

Introduction: Elimination of inflammation and re-osseointegration are the major objectives of peri-implantitis therapy. Existing data, however, do not support any decontamination approach. Thus, the present in vitro study aims to assess whether the air-debriding decontamination method with erythritol powder restores the biocompatibility of infected titanium discs and to investigate the potent biomodulatory ability of diode laser (810 nm) irradiation to promote cell proliferation and differentiation of premature osteoblast-like cells (MG63) towards osteocytes. Methods: The experimental groups consisted of cells seeded on titanium discs exposed or not in a peri-implantitis environment with or without biomodulation. Infected discs were cleaned with airflow with erythritol powder. Cell cultures seeded on tricalcium phosphate (TCP) surfaces with or without biomodulation with a laser (810 nm) were used as controls. The study evaluated cell viability, proliferation, adhesion (SEM) at 24, 48 and 72 hours, and surface roughness changes (profilometry), as well as the effects of low-level laser therapy (LLLT) on ALP, OSC, TGF-b1, Runx2, and BMP-7 expression in MG63 cells' genetic profile on days 7, 14, and 21. Results: The MTT assay as well as the FDA/PI method revealed that cell proliferation did not show significant differences between sterile and decontaminated discs at any timepoint. SEM photographs on day 7 showed that osteoblast-like cells adhered to both sterile and disinfected surfaces, while surface roughness did not change based on amplitude parameters. The combination of airflow and LLLT revealed a biomodulated effect on the differentiation of osteoblast-like cells with regard to the impact of laser irradiation on the genetic profile of the MG63 cells. Conclusion: In all groups tested, osteoblast-like cells were able to colonize, proliferate, and differentiate, suggesting a restoration of biocompatibility of infected discs using airflow. Furthermore, photomodulation may promote the differentiation of osteoblast-like cells cultured on both sterile and disinfected titanium surfaces.

Directed regulation of anammox communities based on exogenous siderophores for highly efficient nitrogen removal

It is expected that the quicker domestication of anaerobic ammonia oxidation (anammox) communities and the enhancement of their nitrogen transformation capability can be achieved through targeted regulation of anammox communities. Iron cast a vital role in the growth and metabolism of anammox bacteria. Specific siderophores offer promising prospects for the targeted regulation of anammox communities by facilitating the efficient utilization of iron. Two siderophores-enterobactin and putrebactin-exclusively for Ca. Brocadia and Ca. Kuenenia were developed to specifically regulate anammox communities towards different directions, respectively. Anammox communities in the reactors evoluted targetedly towards Ca. Brocadia-dominated communities and Ca. Kuenenia-dominated communities, respectively, leading to a maximum increase in community nitrogen removal capacity by 84.64±0.55% and 210.26±0.57%, respectively, under different nitrogen concentrations. It was indicated that siderophores could regulate anammox communities by redistributing iron resources in a targeted manner based on the analyses of transcriptome and proteome. This study provides novel insights into the rational selection and utilization of exogenous siderophores as an effective implement to manipulate anammox communities and create communities with high nitrogen removal ability fleetly.

Surface decontamination of explanted peri-implantitis-affected implants

AIM

The present study aimed at evaluating the effect of air-polishing (AP) and a combination of AP and alkaline electrolysed water (AEW) in surface decontamination of explanted peri-implantitis-affected implants.

MATERIALS AND METHODS

Twenty-five patients with 34 dental implants scheduled for explantation due to severe peri-implantitis were included. Following implant removal, the apical part of each implant was embedded in acrylic blocks. Implants were randomly allocated to surface decontamination using AP with or without AEW. Four implants were left untreated and used as negative controls. Specimens were analysed using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). Area of residual bacteria was the primary outcome.

RESULTS

SEM analysis revealed that both treatment protocols were effective in biofilm removal and only small proportions of target areas of the implants showed residual bacterial or mineralized deposits. Although differences between the treatment protocols were small, implant thread loci (top/flank/valley), zones of the implant (apical/middle/coronal), implant surface characteristics and gender influenced the results. In addition, EDS analysis showed that zones influenced the atomic% of carbon and calcium and that implant surface characteristics affected the atomic% of titanium.

CONCLUSIONS

AP, with or without AEW, is an effective method in removing biofilm from peri-implantitis-affected implants.

Influence of eight debridement techniques on three different titanium surfaces: A laboratory study

OBJECTIVES

Debridement methods may damage implant surfaces. This in vitro study investigated eight debridement protocols across three implant surfaces to assess both biofilm removal and surface alterations.

MATERIAL AND METHODS

One hundred sixty commercially pure titanium discs were treated to simulate commercially available titanium implant surfaces-smooth, abraded and abraded and etched. Following inoculation with whole human saliva to create a mixed species biofilm, the surfaces were treated with eight debridement methods currently used for clinical peri-implantitis (n = 10). This included air abrasion using powders of glycine, sodium bicarbonate and calcium carbonate; conventional mechanical methods-piezoelectric scaler, carbon and stainless steel scalers; and a chemical protocol using 40% citric acid. Following treatment, remaining biofilm was analysed using scanning electron microscopy and crystal violet assays. For statistical analysis, ANOVA was applied (p < 0.05).

RESULTS

All debridement techniques resulted in greater than 80% reduction in biofilm compared with baseline, irrespective of the surface type. Glycine powder delivered through an air polishing system eliminated the most biofilm. Mechanical instruments were the least effective at eliminating biofilm across all surfaces and caused the greatest surface alterations. Citric acid was comparable with mechanical debridement instruments in terms of biofilm removal efficacy. Titanium surfaces were least affected by air abrasion protocols and most affected by mechanical methods.

CONCLUSIONS

Mechanical protocols for non-surgical debridement should be approached with caution. Glycine powder in an air polisher and 40% citric acid application both gave minimal alterations across all implant surfaces, with glycine the superior method in terms of biofilm removal.

Debridement of contaminated implants using air-polishing coupled with pH-responsive maximin H5-embedded metal-organic frameworks

The primary goal of peri-implantitis treatments remains the decontamination of implant surfaces exposed to polymicrobial biofilms and renders biocompatibility. In this study, we reported a synergistic strategy for the debridement and re-osteogenesis of contaminated titanium by using erythritol air abrasion (AA) coupled with an as-synthesized pH-responsive antimicrobial agent. Here, the anionic antibacterial peptide Maximin H5 C-terminally deaminated isoform (MH5C) was introduced into the Zeolitic Imidazolate Frameworks (ZIF-8) via a one-pot synthesis process. The formed MH5C@ZIF-8 nanoparticles (NPs) not only possessed suitable stability, but also guarantee the slow-release effect of MH5C. Antibacterial experiments revealed that MH5C@ZIF-8 NPs exhibited excellent antimicrobial abilities toward pathogenic bacteria of peri-implantitis, confirming ZIF-8 NPs as efficient nanoplatforms for delivering antibacterial peptide. To evaluate the comprehensive debridement efficiency, single-species as well as mixed-species biofilms were successively established on commercially used titanium surfaces and decontaminated with different methods: removed only by erythritol air abrasion, treated merely with MH5C@ZIF-8 NPs, or received both managements. The results demonstrated that only erythritol air abrasion accompanied with MH5C@ZIF-8 NPs at high concentrations eliminated almost all retained bacteria and impeded biofilm rehabilitation, while neither erythritol air abrasion nor MH5C@ZIF-8 NPs alone could achieve this. Subsequently, we evaluated the re-osteogenesis on previously contaminated surfaces which were treated with different debridement methods afterwards. We found that cell growth and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) in the group received both treatments (AA + MH5C@ZIF-8) were higher than those in other groups. Our work emphasized the great potential of the synergistic therapy as a credible alternative for removing microorganisms and rendering re-osseointegration on contaminated implant surfaces, boding well for the comprehensive applications in peri-implantitis treatments.

[Efficacy of combined application of glycine powder air-polishing in non-surgical treatment of peri-implant diseases]

OBJECTIVE

To compare the clinical efficacy of combined application of glycine powder air-polishing and mechanical submucosal debridement in non-surgical treatment of peri-implant diseases.

METHODS

A randomized controlled clinical study was carried out on patients diagnosed with peri-implant diseases in the Department of Periodontology, Peking University School and Hospital of Stomatology, between May of 2020 and June of 2021.Twenty-eight patients with totally sixty-two implants were enrolled.The patients were randomly divided into the test group and control group. The patients in the test group (13 subjects/32 implants) received mechanical submucosal debridement using titanium curettes combined with application of glycine powder air-polishing, while the control group (15 subjects/30 implants) received mechanical submucosal debridement using titanium only. Clinical parameters, such as plaque index (PLI), pocket probing depth (PPD), bleeding index (BI) and the percentage of suppuration on probing on implants' level (SoP%) were measured at baseline and 8 weeks after non-surgical intervention. Changes and group differences of clinical parameters of the implants before and 8 weeks after non-surgical intervention were compared.

RESULTS

Mean PLI, PPD, BI of both the test group and control group significantly reduced 8 weeks after non-surgical intervention (P < 0.05). Compared with the control group, the test group achieved lower BI (2.7±0.8 vs. 2.2±0.7, P < 0.05), more reduction of BI (0.6±0.7 vs. 1.1±0.6, P < 0.01) and more reduction of SoP% (21.9% vs. 10%, P < 0.05) after non-surgical intervention. Both the control and test groups exhibited comparable PLI and PPD reductions (P>0.05). For the implants diagnosed with peri-implant mucositis, the test group revealed more signi-ficant reduction in BI and SoP% than the control group (1.0±0.7 vs. 0.4±0.7, P=0.02; 6.3% vs. 0, P=0.012). There was no significant difference existing in PLI and PD improvement between the control group and test group (P>0.05). For the implants diagnosed with peri-implantitis, there was no significant difference existing in PLI, PPD, BI and SoP% improvement values between the test and control groups (P>0.05). No complications or discomforts were reported during the study.

CONCLUSION

Both treatment procedures could relieve the inflammation of peri-implant soft tissue. Non-surgical mechanical submucosal debridement combined application of glycine powder air-polishing is associated with significant reduction of soft tissue bleeding and suppuration on probing especially in the implants diagnosed with peri-implant mucositis.