Comparison between two antimicrobial protocols with or without guided bone regeneration in the treatment of peri-implantitis. A histomorphometric study in dogs

Effectiveness of 2D magnesium phosphate hydrogel for surgical decontamination of dental implants: A case series

Dental implants, recognized for their enhanced functionality and aesthetic outcomes, are susceptible to peri-implant mucositis and subsequent peri-implantitis when oral hygiene is inadequate. Effective biofilm management is critical to prevent and manage these prevalent conditions and promote implant longevity. Materials with a two-dimensional (2D) structure have demonstrated robust antimicrobial properties. Among these, 2D magnesium phosphates have garnered significant attention due to their additional biocompatibility and osteoconductive properties. This case series explores the application of a thixotropic inorganic hydrogel, composed of 2D magnesium phosphate, in the surgical treatment of dental implant infections. The hydrogel was used for surgical dental implant decontamination in patients diagnosed with peri-implantitis characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. The study encompassed eight cases with a history of peri-implantitis. Clinical measurements were recorded before and after treatment, including bleeding on probing, suppuration, and probing depth. Radiographic evaluations were conducted to assess the exposure of implant threads. The findings revealed a statistically significant decrease in probing depth, bleeding on probing, and the number of exposed implant threads following treatment with the magnesium phosphate hydrogel, though the exact role of the hydrogel in these improvements warrants further exploration.

Hyperbranched Poly-l-Lysine Modified Titanium Surface With Enhanced Osseointegration, Bacteriostasis, and Anti-Inflammatory Properties for Implant Application: An Experimental In Vivo Study

OBJECTIVES

This study aimed to explore multiple effects of hyperbranched poly-l-lysine (HBPL) titanium (Ti) surfaces on osseointegration, bacteriostasis, and anti-inflammation across three different animal models.

METHODS

Ti surfaces were covalently modified with HBPL, with uncoated surfaces as controls. Characterization included scanning electron microscopy (SEM) and surface chemistry and elemental analysis (EDX). Ti and Ti-HBPL implants were placed in conventional canine edentulous sites, post-operative infection canine edentulous sites, and diabetic rat tibias. Implants from canine edentulous models were analyzed using micro-CT and histomorphometry to assess osseointegration at 8 weeks. Post-operative infection beagles were used to evaluate antibacterial efficacy through clinical parameters and bacterial cultures at 1 week. In diabetic rats, micro-CT and histomorphometry were performed at 8 weeks.

RESULTS

HBPL was uniformly grafted on Ti-HBPL surfaces. Ti-HBPL surfaces showed higher bone volume/total volume (BV/TV, p < 0.001), bone-implant contact (BIC%, p < 0.001), and trabecular number (Tb.N, p < 0.01) in beagles. Besides, it displayed higher BIC% (p < 0.001) and bone area fraction occupancy (BAFO%, p < 0.01) in hard tissue sections. In an infected model, Ti-HBPL surfaces exhibited lower bleeding on probing (BOP, p < 0.001), and plaque index (DI, p < 0.01), with reduced bacterial colony formation (p < 0.001) compared to the control group. In diabetic rats, Ti-HBPL surfaces showed an increase in BV/TV (p < 0.01) and Tb.N (p < 0.001), downregulated TNF-α and IL-1β (p < 0.01), and upregulated IL-10 (p < 0.01) and osteocalcin (OCN) expression (p < 0.01).

CONCLUSIONS

HBPL-Ti surfaces demonstrated enhanced osseointegration, bacteriostasis, and anti-inflammatory effects in vivo.

Efficacy of surgical methods for peri-implantitis: a systematic review and network meta-analysis

BACKGROUND

Peri-implantitis is the most difficult biological complication associated with dental implants, often requiring surgical treatments in advanced stages. This study compares the effectiveness of different surgical methods for peri-implantitis.

METHODS

Randomized controlled trials (RCTs) of different surgical treatments for peri-implantitis were extracted from EMBASE, Web of Science, Cochrane Library databases, and PubMed systematically. Pairwise comparisons and network meta-analyses (NMA) were conducted to analyze the effect of surgical treatments on probing depth (PD), radiographic bone fill (RBF), mucosal recession (MR), bleeding on probing (BOP), and clinical attachment level (CAL). In addition, risk of bias, quality of evidence, and statistical heterogeneity of the selected studies were evaluated. A total of 13 articles were included in this study, involving open flap debridement (OFD), resective therapy (RT), and augmentative therapy (AT) with and without adjunctive treatments (laser therapy, photodynamic therapy, local antibiotics, phosphoric acid, and ozone therapy).

RESULTS

AT improved RBF and CAL more than OFD, but does not outperform OFD in reducing peri-implant soft-tissue inflammation. AT, OFD and RT did not significantly alter the levels of MR. Addition of ozone therapy improved the effect of AT, but addition of photodynamic therapy did not affect PD reduction and CAL gain significantly. Similarly, adjuvant treatment with phosphoric acid during RT did not significantly change the outcome of BOP.

CONCLUSIONS

Within the limitation of this systematic review and NMA, AT was superior to OFD in improving peri-implantitis outcomes. While adjunct use of ozone therapy may further improve the efficacy of AT, the limited evidence supporting this combination therapy argues for cautionary interpretation of these results.

Reconstructive Peri-Implantitis Therapy by Using Bovine Bone Substitute with or without Hyaluronic Acid: A Randomized Clinical Controlled Pilot Study

BACKGROUND

The present pilot study aimed to assess clinical and radiographic efficiencies of bovine bone substitute (BBS) merged with hyaluronic acid (HA) in peri-implantits reconstructive surgery.

METHODS

Peri-implantitis (diagnosed 6.03 ± 1.61 years of implant loading) bone defects were randomly treated either with BBS plus HA (test group) or BBS alone (control group). Clinical parameters including peri-implant probing depth (PPD), bleeding on probing (BOP), implant stability (ISQ), and radiographic changes in vertical and horizontal marginal bone (MB) levels were assessed at six months postoperatively. New temporary and permanent screw-retained crowns were made at two weeks and three months postoperatively. Data were analyzed using parametric and non-parametric tests.

RESULTS

In both groups, 75% of patients and 83% of implants achieved treatment success after six months (no BOP, PPD <5 mm, and no further MB loss). Clinical outcomes improved over time within groups; however, without significant difference between them. ISQ value obtained significant increases in the test compared to the control group at six months postoperatively (p < 0.05). The vertical MB gain was significantly greater in the test group compared to the control (p < 0.05).

CONCLUSIONS

Short-term outcomes suggested that BBS merged with HA could improve clinical and radiographic outcomes in peri-implantitis reconstructive therapy.

Network pharmacology combined with GEO database identifying the mechanisms and molecular targets of Polygoni Cuspidati Rhizoma on Peri-implants

Peri-implants is a chronic disease leads to the bone resorption and loss of implants. Polygoni Cuspidati Rhizoma (PCRER), a traditional Chinese herbal has been used to treat diseases of bone metabolism. However, its mechanism of anti-bone absorption still remains unknown. We aimed to identify its molecular target and the mechanism involved in PCRER potential treatment theory to Peri-implants by network pharmacology. The active ingredients of PCRER and potential disease-related targets were retrieved from TCMSP, Swiss Target Prediction, SEA databases and then combined with the Peri-implants disease differential genes obtained in the GEO microarray database. The crossed genes were used to protein–protein interaction (PPI) construction and Gene Ontology (GO) and KEGG enrichment analysis. Using STRING database and Cytoscape plug-in to build protein interaction network and screen the hub genes and verified through molecular docking by AutoDock vina software. A total of 13 active compounds and 90 cross targets of PCRER were selected for analysis. The GO and KEGG enrichment analysis indicated that the anti-Peri-implants targets of PCRER mainly play a role in the response in IL-17 signaling, Calcium signaling pathway, Toll-like receptor signaling pathway, TNF signaling pathway among others. And CytoHubba screened ten hub genes (MMP9, IL6, MPO, IL1B, SELL, IFNG, CXCL8, CXCL2, PTPRC, PECAM1). Finally, the molecular docking results indicated the good binding ability with active compounds and hub genes. PCRER’s core components are expected to be effective drugs to treat Peri-implants by anti-inflammation, promotes bone metabolism. Our study provides new thoughts into the development of natural medicine for the prevention and treatment of Peri-implants.

Surgical therapy of peri-implantitis

Peri-implantitis is caused by a bacterial challenge; therefore, anti-infective treatment strategies should be employed to manage the disease. As nonsurgical approaches demonstrate limited efficacy in most cases of peri-implantitis, surgical interventions are often required. Treatment outcomes improve following access flap surgery, with or without adjunctive resective and/or augmentation measures. Whereas nonaugmentative therapies (ie, access flap surgery and resective techniques) primarily aim to resolve inflammation and arrest further disease progression, augmentation approaches also seek to regenerate the bony defect and achieve reosseointegration. Currently, limited evidence supports the superiority of augmentative surgical techniques for peri-implantitis treatment over nonaugmentation methods, and human histologic evidence for reosseointegration is sparse. For patients involved in regular postoperative maintenance programs, success of peri-implantitis surgical treatment based on various definitions of success was obtained in over half of the cases after 5-7 years. Despite surgical treatment, cases of further disease progression that required retreatment or led to implant loss were reported.

Anti-infection mechanism of a novel dental implant made of titanium-copper (TiCu) alloy and its mechanism associated with oral microbiology

This work was focused on study of anti-infection ability and its underlying mechanism of a novel dental implant made of titanium-copper (TiCu) alloy. In general, most studies on antibacterial implants have used a single pathogen to test their anti-infection ability using infectious animal models. However, dental implant-associated infections are polymicrobial diseases. We innovatively combine the classic ligature model in dogs with sucrose-rich diets to induce oral infections via the canine native oral bacteria. The anti-infection ability, biocompatibility and underlying mechanism of TiCu implant were systematically investigated in comparison with pure Ti implant via general inspection, hematology, imageology (micro-CT), microbiology (16S rDNA and metagenome), histology, and Cu ion detections. Compared with Ti implant, TiCu implant demonstrated remarkable anti-infection potentials with excellent biocompatibility. Additionally, the underlying anti-infection mechanism of TiCu implant was considered to involve maintaining the oral microbiota homeostasis. It was found that the carbohydrates in the plaques formed on the surface of TiCu implant were metabolized through the tricarboxylic acid cycle (TCA) cycles, which prevented the formation of an acidic microenvironment and inhibited the accumulation of acidogens and pathogens, thereby maintaining the microflora balance between aerobic and anaerobic bacteria.

Pre-Clinical Models in Implant Dentistry: Past, Present, Future

Biomedical research seeks to generate experimental results for translation to clinical settings. In order to improve the transition from bench to bedside, researchers must draw justifiable conclusions based on data from an appropriate model. Animal testing, as a prerequisite to human clinical exposure, is performed in a range of species, from laboratory mice to larger animals (such as dogs or non-human primates). Minipigs appear to be the animal of choice for studying bone surgery around intraoral dental implants. Dog models, well-known in the field of dental implant research, tend now to be used for studies conducted under compromised oral conditions (biofilm). Regarding small animal models, research studies mostly use rodents, with interest in rabbit models declining. Mouse models remain a reference for genetic studies. On the other hand, over the last decade, scientific advances and government guidelines have led to the replacement, reduction, and refinement of the use of all animal models in dental implant research. In new development strategies, some in vivo experiments are being progressively replaced by in vitro or biomaterial approaches. In this review, we summarize the key information on the animal models currently available for dental implant research and highlight (i) the pros and cons of each type, (ii) new levels of decisional procedures regarding study objectives, and (iii) the outlook for animal research, discussing possible non-animal options.

Antimicrobial Photodynamic Therapy (aPDT) as a Disinfection and Biomodulation Approach in Implant Dentistry

This article is a highlight of the paper by Choe et al. in this issue of Photochemistry and Photobiology. In that review paper, the disinfection and biomodulation outcomes promoted by antimicrobial photodynamic therapy (aPDT) on peri-implantitis infection were stated and discussed. The killing of the oral pathogens by aPDT is based on the generation of reactive oxygen species (ROS). Besides that, biomodulation can also be provided by aPDT and improve the healing and modulate the inflammatory process. Although aPDT has shown positive effects on the treatment of peri-implantitis disease mainly as a complimentary technique, the authors suggested that more and standardize clinical studies are needed to support the clinical application of aPDT for that purpose. Also, the standardization of parameters related to the light source and photosensitizers is required. In addition, nano-based materials may improve aPDT performance against oral biofilms and could increase the hopes of overcoming dental implant failures.

Peri-Implantitis Regenerative Therapy: A Review

Simple Summary

Regenerative therapies are one of the options to treat peri-implantitis diseases that cause peri-implant bone loss. This review reports classic and current literature to describe the available knowledge on regenerative peri-implant techniques.

Abstract

The surgical techniques available to clinicians to treat peri-implant diseases can be divided into resective and regenerative. Peri-implant diseases are inflammatory conditions affecting the soft and hard tissues around dental implants. Despite the large number of investigations aimed at identifying the best approach to treat these conditions, there is still no universally recognized protocol to solve these complications successfully and predictably. This review will focus on the regenerative treatment of peri-implant osseous defects in order to provide some evidence that can aid clinicians in the approach to peri-implant disease treatment.

Photodynamic Therapy for Biomodulation and Disinfection in Implant Dentistry: Is It Feasible and Effective?

Dental implants are the most common rehabilitation and restorative treatment used to replace missing teeth. Biofilms adhere to implant surfaces to trigger implant-associated infection and inflammatory response. Clinically, the biofilm induces a local host response with the infiltration of phagocytic immune cells. The pro-inflammatory surroundings set off osteoclastogenesis, which leads to the septic loosening of the implant. The standard of dental care for implant-associated infection relies on a combination of surgery and antimicrobial therapy. Antimicrobial photodynamic therapy is a noninvasive and photochemistry-based approach capable of reducing bacterial load and modulating inflammatory responses. In this review, we explore the photobiomodulation and disinfection outcomes promoted by photodynamic therapy for implant infections, highlighting the quality of evidence on the most up-to-date studies, and discuss the major challenges on the advance of these therapeutic strategies.

Evaluation of air polishing with a sterile powder and mechanical debridement during regenerative surgical periimplantitis treatment: a study in dogs

Objectives

To evaluate the effectiveness of mechanical debridement and/or air polishing on the healing of ligature-induced buccal periimplantitis dehiscence defects in dogs.

Material and methods

Forty-eight implants were placed in the mandibles of twelve beagle dogs, and periimplantitis was induced for 2 months using ligatures. The resulting buccal dehiscence-type defects were surgically cleaned and augmented (xenogenic filler and resorbable membrane) according to one of the following treatments: (1) Cleaning with carbon curette (debridement - D) and guided bone regeneration (GBR/G): DG, (2) air polishing cleaning (A) and GBR: AG, (3) a combination of D/A/G: DAG, and (4) D/A without GBR: DA. After 2 months, histomorphometric and inflammatory evaluations were conducted.

Results

The median bone gain after therapy ranged between 1.2 mm (DG) and 2.7 mm (AG). Relative bone gain was between 39% (DG) and 59% (AG). The lowest inflammation scores were obtained in DA without GBR (5.84), whereas significantly higher values between 8.2 and 9.4 were found in the groups with augmentation. At lingual sites without defects, scores ranged from 4.1 to 5.9. According to ISO, differences above 2.9 were considered representative for irritative properties.

Conclusions

All treatments resulted in partial regeneration of the defects. No treatment group showed a significantly (p < 0.05) better outcome. However, pretreatment with air polishing showed a tendency for less inflammation. Noteworthy, inflammation assessment showed an overall irritative potential after GBR in the evaluated early healing phase.

Clinical relevance

Periimplantitis treatment still represents a big issue in daily practice and requires additional preclinical research in order to improve treatment concepts.

Graphene Oxide Enables the Reosteogenesis of Previously Contaminated Titanium In Vitro

The main goal of peri-implantitis treatment is to control infection and arrest bone loss, which requires the removal of polymicrobial biofilms on the implant surface and the reduction of tissue invasion. Additionally, prognosis can be improved if reosseointegration occurs on previously contaminated implants. To evaluate whether graphene oxide (GO) can remove polymicrobial biofilms, biofilms were established on titanium surfaces in vitro and treated with different methods: group B, removed only with brushing; group G, treated with different GO concentrations (64, 128, 256, and 512 μg/mL); group GB, combined treatments of groups B and G; and group C, untreated. Subsequently, to evaluate reosteogenesis on previously contaminated titanium, 4 groups were used: groups C, B, GB-256, and GB-512 (treated with 256 and 512 μg/mL of GO, respectively). Intact clean titanium (IC) was used as a control. Additionally, cell behavior on IC treated with GB-256 (IGB-256) and GB-512 (IGB-512) was compared with that of the GB-256 and GB-512 groups, respectively. The results showed that at high concentrations (≥256 μg/mL), GO eliminated residual bacteria and inhibited biofilm reformation after brushing, whereas neither GO nor brushing alone could achieve this. Bone marrow-derived mesenchymal stem cell viability in groups GB-256 and IC was higher than that in groups GB-512, C, and B (P < 0.05). No significant difference was found between group GB-256 and group IC (P > 0.05). Osteogenic differentiation of bone marrow-derived mesenchymal stem cells in group GB-256 was higher than that in groups IC, GB-512, C, and B. No difference was found between groups IGB-256 and IGB-512 and groups GB-256 and GB-512, respectively (P > 0.05). In conclusion, 256 μg/mL of GO combined with brushing significantly removed polymicrobial biofilms that remained on the previously contaminated titanium surfaces. The bone marrow-derived mesenchymal stem cell osteogenic potential was regained or even enhanced on the titanium surfaces treated this way in vitro, which might provide a new idea for treating peri-implantitis.

Reosseointegration after the surgical treatment of induced peri-implantitis: systematic review on current evidence and translation from the animal to the human model

INTRODUCTION

The aim of this study was to review the histologic evidence of reosseointegration and related influencing factors in experimental induced peri-implantitis.

EVIDENCE ACQUISITION

An electronic search was performed on Medline for animal studies that included a histometric evaluation of the amount of regenerated bone in contact with an implant surface. Questions raised in the study focused on the role of implant surfaces, bone regeneration and decontamination treatments in achieving reosseointegration. A detailed electronic search was then conducted on MEDLINE (PubMed) up to July 2017.

EVIDENCE SYNTHESIS

One hundred and one articles were selected as abstract, thirty-seven articles assessed as full-text and sixteen finally included in the study. Reported measurements of reosseointegration varied significantly in the study, from 0 to 3.37 mm. There is histological evidence that reosseointegration can occur after treatment of ligature-induced peri-implantitis. However regenerated bone in contact with bone is generally restricted to the most apical portion of the peri-implant defect.

CONCLUSIONS

Animal studies of induced peri-implantitis seem to indicate that rough surfaces can enhance reosseointegration as compared to smooth surfaces. With regard to bone regeneration techniques and materials, submerged healing and barrier membranes have shown a positive effect on reosseointegration. No evidence exists, however, about the specific role of different bone substitutes and their ability to improve bone formation. Growth factors have been shown to improve reosseointegration in animal models, though additional study is required to confirm the data. Several decontamination treatments have been shown to promote reosseointegration compared to control; however no specific procedure has proven superior to others in achieving reosseointegration.

Guided Bone Regeneration Using Collagen Scaffolds, Growth Factors, and Periodontal Ligament Stem Cells for Treatment of Peri-Implant Bone Defects In Vivo

Introduction

The aim of the study was an evaluation of different approaches for guided bone regeneration (GBR) of peri-implant defects in an in vivo animal model.

Materials and Methods

In minipigs (n = 15), peri-implant defects around calcium phosphate- (CaP-; n = 46) coated implants were created and randomly filled with (1) blank, (2) collagen/hydroxylapatite/β-tricalcium phosphate scaffold (CHT), (3) CHT + growth factor cocktail (GFC), (4) jellyfish collagen matrix, (5) jellyfish collagen matrix + GFC, (6) collagen powder, and (7) collagen powder + periodontal ligament stem cells (PDLSC). Additional collagen membranes were used for coverage of the defects. After 120 days of healing, bone growth was evaluated histologically (bone to implant contact (BIC;%)), vertical bone apposition (VBA; mm), and new bone height (NBH; %).

Results

In all groups, new bone formation was seen. Though, when compared to the blank group, no significant differences were detected for all parameters. BIC and NBH in the group with collagen matrix as well as the group with the collagen matrix + GFC were significantly less when compared to the collagen powder group (all: p < 0.003).

Conclusion

GBR procedures, in combination with CaP-coated implants, will lead to an enhancement of peri-implant bone growth. There was no additional significant enhancement of osseous regeneration when using GFC or PDLSC.