Influence of different instrumentation modalities on the surface characteristics and biofilm formation on dental implant neck, in vitro

The clinical efficacy of powder air-polishing in the non-surgical treatment of peri-implant diseases: A systematic review and meta-analysis

Peri-implant diseases, characterized by inflammatory conditions affecting peri-implant tissues, encompass peri-implant mucositis and peri-implantitis. Peri-implant mucositis is an inflammatory lesion limited to the mucosa around an implant, while peri-implantitis extends from the mucosa to the supporting bone, causing a loss of osseointegration. For non-surgical treatments, we tested the null hypothesis that the presence or absence of air-polishing made no difference. The study focused on randomized controlled trials (RCTs) comparing air-polishing with mechanical or ultrasonic debridement, evaluating outcomes such as bleeding on probing (BOP), probing depth (PD), plaque index/plaque score (PI/PS), clinical attachment level (CAL), bone loss, and mucosal recession (MR). Two independent reviewers conducted data extraction and quality assessments, considering short-term (<6 months) and long-term (≥6 months) follow-up periods. After screening, ten articles were included in the meta-analysis. In nonsurgical peri-implant disease management, air-polishing moderately mitigated short-term PI/PS for peri-implant mucositis and showed a similar improvement in long-term BOP and bone loss for peri-implantitis compared to the control group. The Egger test found no evidence of publication bias except for the long-term PI/PS of peri-implant mucositis. Leave-one-out analysis confirmed the stability of the results. The findings highlight the need for future research with longer-term follow-up and high-quality, multi-center, large-sample RCTs.

In vitro evaluation of surface roughness of titanium abutments after air polishing with different abrasive powders

OBJECTIVES

The purpose of this study was to evaluate the effects of air polishing with sodium bicarbonate and erythritol powders on surface roughness and morphological changes in titanium abutments.

METHODS

A total of 45 grade V titanium discs were divided in three groups: Group A (Control) air polished with air/water; Group B, air polished with sodium bicarbonate powder; and Group C, air polished with erythritol powder. After air polishing, the samples' roughness (Sa) in micrometres were analysed with an optical profilometer. The samples' surface morphology study was conducted via scanning electronic microscope (SEM). Data were described using mean and standard deviation of roughness values (Sa). Inferential analysis was performed using the ANOVA multiple comparison test followed by Tukey's post hoc test. Both tests used a 5% level of significance.

RESULTS

After air polishing, average roughness of group A, B and C were 0.036, 0.046 and 0.037 μm, respectively, with statistically significant differences between groups A and B (p < 0.05). No statistically significant differences were found between group A and group C, as well as between group B and C (p > 0.05). As for the morphology analysis, damages to the titanium surface were only observed in group B.

CONCLUSIONS

The study indicates that air polishing with erythritol powder maintains titanium abutment integrity better than sodium bicarbonate, which increased surface roughness and caused damage. Erythritol is preferable for minimizing surface alterations and maintaining morphological stability.

Efficacy and safety of erythritol air-polishing in implant dentistry: A systematic review

OBJECTIVES

Professional oral hygiene is essential to prevent peri-implant disease. Appropriate instruments should be employed for implant-supported restorations: they should effectively remove deposits without damaging dental implant surface. The aim of the present systematic review is to investigate the efficacy and safety of erythritol air-polishing in implant-supported rehabilitations, compared to alternative hygienic techniques.

MATERIALS AND METHODS

The guidelines reported in the indications of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) were employed for this systematic review. The focused question was: 'what is the effect of erythritol air-polishing on dental implant surfaces regarding its cleansing efficacy and/or safety?' The final online search was conducted on 13 August 2023; MEDLINE-PubMed, Scopus and Cochrane Library were employed. Comparative in vitro or in vivo original studies were included.

RESULTS

The initial database search yielded 128 entries; the final selection comprised 15 articles. The risk of bias was evaluated using the Newcastle Ottawa scale (NOS), the Cochrane Handbook for Systematic Reviews of Interventions, GRADE method. Ultrasonic scaling with PEEK tips, glycine air-polishing and cold atmospheric plasma were the devices most frequently compared to erythritol powder in the included studies. Erythritol air-polishing appeared to be significantly more effective in reducing biofilm compared to other treatments, without causing any significant damage to the implant surface and peri-implant tissues, promoting a good biological response.

CONCLUSION

Erythritol air-polishing showed promising results for professional oral hygiene in implant-supported restorations. According to this systematic review, it is effective and safe for removing biofilm from titanium dental implants.

A Review of Bacterial Colonization on Dental Implants With Various Hygiene Instruments

Peri-implant diseases can still develop despite oral hygiene practices being maintained. Consequently, regular debridement must be carried out to ensure the implant is sustained. This review evaluated bacterial colonization on implants following the use of different hygiene instruments. A literature search was conducted in PubMed, ScienceDirect, and Scopus databases for articles published from 2012 to 2022. A total of 19 full-text papers were selected. The number of bacteria colonized was most commonly evaluated with a scanning electron microscope (SEM) or by colony-forming unit (CFU) counts, crystal violet assays, plaque index, probing depth, bleeding on probing, turbidity test, and live-dead assays. Rubber cup polishing with an abrasive paste showed a significantly greater reduction in biofilm formation compared with air abrasion with glycine powder, while the air abrasion treatment was found to be more efficient than piezoelectric, carbon, and stainless steel scalers. Surface treatment with Er, Cr: YSGG laser, and Er: YAG laser resulted in statistically significant superior dental biofilm removal compared with titanium curettes and photodynamic therapy. Air abrasion, plastic curette, titanium curette, and ultrasonic scaler showed no significant differences in bacterial colonization, but air abrasion and plastic curette were safer for zirconia implant decontamination. Furthermore, the titanium brush showed better results in decontaminating the implant surface than the Er: YAG laser. Although no single instrument or method could be considered as offering a gold standard in treating peri-implant diseases, the use of air abrasion with glycine powder, laser therapies, rubber cup polishing with an abrasive paste, and a titanium brush had high levels of cleaning efficacy and acceptance by patients.

Current Status of Peri-Implant Diseases: A Clinical Review for Evidence-Based Decision Making

BACKGROUND

the prevalence of peri-implant diseases is constantly growing, particularly with the increasing use of dental implants. As such, achieving healthy peri-implant tissues has become a key challenge in implant dentistry since it considers the optimal success paradigm. This narrative review aims to highlight the current concepts regarding the disease and summarize the available evidence on treatment approaches clarifying their indications for usage following the World Workshop on the Classification of Periodontal and Peri-implant Diseases (2017).

METHODS

we reviewed the recent literature and conducted a narrative synthesis of the available evidence on peri-implant diseases.

RESULTS

scientific evidence on case definitions, epidemiology, risk factors, microbiological profile, prevention, and treatment approaches for peri-implant diseases were summarized and reported.

CONCLUSIONS

although there are numerous protocols for managing peri-implant diseases, they are diverse and nonstandardized, with no consensus on the most effective, leading to treatment confusion.

Craniofacial therapy: advanced local therapies from nano-engineered titanium implants to treat craniofacial conditions

Nano-engineering-based tissue regeneration and local therapeutic delivery strategies show significant potential to reduce the health and economic burden associated with craniofacial defects, including traumas and tumours. Critical to the success of such nano-engineered non-resorbable craniofacial implants include load-bearing functioning and survival in complex local trauma conditions. Further, race to invade between multiple cells and pathogens is an important criterion that dictates the fate of the implant. In this pioneering review, we compare the therapeutic efficacy of nano-engineered titanium-based craniofacial implants towards maximised local therapy addressing bone formation/resorption, soft-tissue integration, bacterial infection and cancers/tumours. We present the various strategies to engineer titanium-based craniofacial implants in the macro-, micro- and nano-scales, using topographical, chemical, electrochemical, biological and therapeutic modifications. A particular focus is electrochemically anodised titanium implants with controlled nanotopographies that enable tailored and enhanced bioactivity and local therapeutic release. Next, we review the clinical translation challenges associated with such implants. This review will inform the readers of the latest developments and challenges related to therapeutic nano-engineered craniofacial implants.

Hard and soft tissue regeneration of severe peri-implantitis defects with the laser-assisted peri-implant defect regeneration technique: 3-year results

PURPOSE

This retrospective cohort study evaluates the regeneration of severe peri-implantitis deficiencies treated with the laser-assisted peri-implant defect regeneration (LAPIDER) approach within a 3-year follow-up.

METHODS

Twenty-four implants with severe peri-implantitis in 18 patients were treated according to the LAPIDER technique. In contrast to classic techniques for reconstructive peri-implantitis surgery with a marginal incision, a buccal split-flap preparation avoiding papillae separation was used. After a coronal flap elevation and a laser-assisted peri-implant defect cleaning, connective tissue and autogenous bone grafting was performed. Primary outcomes were the changes of the marginal bone levels (MBL) and the buccal bone thickness. Secondary outcomes included implant survival, peri-implant probing depths (PPD), bleeding on probing (BOP), recession, width of keratinized mucosa (KMW), thickness of keratinized mucosa (KMT), soft tissue esthetics (PES), and implant success.

RESULTS

MBL improved interproximal by 3.10 ± 2.02 mm (p < 0.001), buccal by 3.49 ± 2.89 mm (p < 0.001), and lingual by 1.46 ± 1.98 mm (p = 0.003); buccal bone thickness by 0.55 ± 0.60 mm (p = 0.005), and 1.01 ± 1.25 mm (p = 0.001) at 1 and 3 mm below reference level. Two implants were removed; 22 implants were still in function at a mean follow-up of 36 months. PPD changed from 5.05 ± 1.39 to 3.08 ± 0.71 mm (p < 0.001); recession was reduced from 2.07 ± 1.70 to 0.91 ± 1.13 mm (p = 0.001); KMW increased from 2.91 ± 1.81 to 4.18 ± 1.67 mm (p = 0.006); KMT improved from 1.73 ± 0.50 to 2.44 ± 0.43 mm (p < 0.001); PES changed from 7.7 ± 2.8 to 10.7 ± 1.9 (p < 0.001). 45.8% to 54.2% of the implants met the criteria of implant success.

CONCLUSIONS

The favorable results document the proof of principle for the regeneration of severe peri-implant hard and soft tissue deficiencies by the LAPIDER treatment approach.

D-arginine Enhances the Effect of Alpha-Amylase on Disassembling Actinomyces viscosus Biofilm

Peri-implantitis is the leading cause of dental implant failure, initially raised by biofilm accumulation on the implant surface. During the development of biofilm, Actinomyces viscosus (A. viscosus) plays a pivotal role in initial attachment as well as the bacterial coaggregation of multispecies pathogens. Hence, eliminating the A. viscosus-associated biofilm is fundamental for the regeneration of the lost bone around implants. Whereas clinical evidence indicated that antimicrobials and debridement did not show significant effects on the decontamination of biofilm on the implant surface. In this study, alpha-amylase was investigated for its effects on disassembling A. viscosus biofilm. Then, in order to substantially disperse biofilm under biosafety concentration, D-arginine was employed to appraise its enhancing effects on alpha-amylase. In addition, molecular dynamics simulations and molecular docking were conducted to elucidate the mechanism of D-arginine enhancing alpha-amylase. 0.1–0.5% alpha-amylase showed significant effects on disassembling A. viscosus biofilm, with definite cytotoxicity toward MC3T3-E1 cells meanwhile. Intriguingly, 8 mM D-arginine drastically enhanced the eradication of A. viscosus biofilm biomass by 0.01% alpha-amylase with biosafety in 30 min. The exopolysaccharides of biofilm were also thoroughly hydrolyzed by 0.01% alpha-amylase with 8 mM D-arginine. The biofilm thickness and integrity were disrupted, and the exopolysaccharides among the extracellular matrix were elusive. Molecular dynamics simulations showed that with the hydrogen bonding of D-arginine to the catalytic triad and calcium-binding regions of alpha-amylase, the atom fluctuation of the structure was attenuated. The distances between catalytic triad were shortened, and the calcium-binding regions became more stable. Molecular docking scores revealed that D-arginine facilitated the maltotetraose binding process of alpha-amylase. In conclusion, these results demonstrate that D-arginine enhances the disassembly effects of alpha-amylase on A. viscosus biofilm through potentiating the catalytic triad and stabilizing the calcium-binding regions, thus providing a novel strategy for the decontamination of biofilm contaminated implant surface.

Microbial Biofilm Decontamination on Dental Implant Surfaces: A Mini Review

Introduction

After insertion into the bone, implants osseointegrate, which is required for their long-term success. However, inflammation and infection around the implants may lead to implant failure leading to peri-implantitis and loss of supporting bone, which may eventually lead to failure of implant. Surface chemistry of the implant and lack of cleanliness on the part of the patient are related to peri-implantitis. The only way to get rid of this infection is decontamination of dental implants.

Objective

This systematic review intended to study decontamination of microbial biofilm methods on titanium implant surfaces used in dentistry.

Methods

The electronic databases Springer Link, Science Direct, and PubMed were explored from their inception until December 2020 to identify relevant studies. Studies included had to evaluate the efficiency of new strategies either to prevent formation of biofilm or to treat matured biofilm on dental implant surfaces.

Results and Discussion

In this systematic review, 17 different groups of decontamination methods were summarized from 116 studies. The decontamination methods included coating materials, mechanical cleaning, laser treatment, photodynamic therapy, air polishing, anodizing treatment, radiation, sonication, thermal treatment, ultrasound treatment, chemical treatment, electrochemical treatment, antimicrobial drugs, argon treatment, and probiotics.

Conclusion

The findings suggest that most of the decontamination methods were effective in preventing the formation of biofilm and in decontaminating established biofilm on dental implants. This narrative review provides a summary of methods for future research in the development of new dental implants and decontamination techniques.

Influence of Nano, Micro, and Macro Topography of Dental Implant Surfaces on Human Gingival Fibroblasts

Current research on dental implants has mainly focused on the influence of surface roughness on the rate of osseointegration, while studies on the development of surfaces to also improve the interaction of peri-implant soft tissues are lacking. To this end, the first purpose of this study was to evaluate the response of human gingival fibroblasts (hGDFs) to titanium implant discs (Implacil De Bortoli, Brazil) having different micro and nano-topography: machined (Ti-M) versus sandblasted/double-etched (Ti-S). The secondary aim was to investigate the effect of the macrogeometry of the discs on cells: linear-like (Ti-L) versus wave-like (Ti-W) surfaces. The atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis showed that the Ti-S surfaces were characterized by a significantly higher micro and nano roughness and showed the 3D macrotopography of Ti-L and Ti-W surfaces. For in vitro analyses, the hGDFs were seeded into titanium discs and analyzed at 1, 3, and 5 days for adhesion and morphology (SEM) viability and proliferation (Cck-8 and MTT assays). The results showed that all tested surfaces were not cytotoxic for the hGDFs, rather the nano-micro and macro topography favored their proliferation in a time-dependent manner. Especially, at 3 and 5 days, the number of cells on Ti-L was higher than on other surfaces, including Ti-W surfaces. In conclusion, although further studies are needed, our in vitro data proved that the use of implant discs with Ti-S surfaces promotes the adhesion and proliferation of gingival fibroblasts, suggesting their use for in vivo applications.

Erythritol-enriched powder and oral biofilm regrowth on dental implants: an in vitro study

Background

Peri-implant mucositis and peri-implantitis are the main biological complications associated with dental implants. Since most authors agree that bacteria play a major etiological role, the main aims of this study were to determine if a formulation of erythritol and chlorhexidine applied with an air polishing system inhibits biofilm regrowth over dental implants and to compare the decontamination capacity of this therapy with that of mechanical removal by saline and gauze.

Material and Methods

A multispecies biofilm (P. gingivalis, A. actinomycetemcomitans, F. nucleatum, A. naeslundii, V. parvula and S. oralis) was grown for 14 days on 52 dental implants in an artificial mouth. These implants were divided into three groups according to the applied treatment: 14 negative control (CON), 19 erythritol-chlorhexidine (ERY) and 19 gauze with saline (GAU) samples. Twelve dental implants from the ERY and GAU groups and 8 implants from the CON group were re-incubated for 7 additional days after treatment. The bacterial count was performed by quantitative polymerase chain reaction (qPCR) using propidium monoazide (PMA). A descriptive and bivariate analysis of the data was performed.

Results

The erythritol and chlorhexidine formulation significantly inhibited biofilm regrowth in comparison with the mechanical treatment (GAU), since a significant decrease in all the species was observed in the ERY group (except for Aggregatibacter actinomycetemcomitans). The antibiofilm and antibacterial capacity of the two active treatment groups (ERY and GAU) was similar for a 14 days multispecies in vitro biofilm, except for the lower count of A. naeslundii in the GAU group.

Conclusions

The use of erythritol powder with chlorhexidine applied with an air polishing system reduces biofilm regrowth over dental implants when compared with mechanical removal by saline and gauze. This effect might be beneficial for patients included in peri-implant maintenance programs.

Key words:Dental implants, biofilms, peri-implantitis, erythritol, chlorhexidine.

Graphene-Reinforced Titanium Enhances Soft Tissue Seal

The integrity of soft tissue seal is essential for preventing peri-implant infection, mainly induced by established bacterial biofilms around dental implants. Nowadays, graphene is well-known for its potential in biocompatibility and antisepsis. Herein, a new titanium biomaterial containing graphene (Ti-0.125G) was synthesized using the spark plasma sintering (SPS) technique. After material characteristics detection, the subsequent responses of human gingival fibroblasts (HGFs) and multiple oral pathogens (including Streptococci mutans, Fusobacterium nucleatum, and Porphyromonas gingivalis) to the graphene-reinforced sample were assessed, respectively. Also, the dynamic change of the bacterial multispecies volume in biofilms was evaluated using absolute quantification PCR combined with Illumina high-throughput sequencing. Ti-0.125G, in addition to its particularly pronounced inhibitory effect on Porphyromonas gingivalis at 96 h, was broadly effective against multiple pathogens rather than just one strain. The reinforced material’s selective responses were also evaluated by a co-culture model involving HGFs and multiple strains. The results disclosed that the graphene-reinforced samples were highly effective in keeping a balance between the favorable fibroblast responses and the suppressive microbial growth, which could account for the optimal soft tissue seal in the oral cavity. Furthermore, the underlying mechanism regarding new material’s bactericidal property in the current study has been elucidated as the electron transfer, which disturbed the bacterial respiratory chain and resulted in a decrease of microbial viability. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, the PICRUSt tool was conducted for the prediction of microbial metabolism functions. Consequently, it is inferred that Ti-0.125G has promising potentials for application in implant dentistry, especially in enhancing the integrity of soft tissue and improving its resistance against bacterial infections around oral implants.

Relevance of Biofilm Models in Periodontal Research: From Static to Dynamic Systems

Microbial biofilm modeling has improved in sophistication and scope, although only a limited number of standardized protocols are available. This review presents an example of a biofilm model, along with its evolution and application in studying periodontal and peri-implant diseases. In 2011, the ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) research group at the University Complutense of Madrid developed an in vitro biofilm static model using representative bacteria from the subgingival microbiota, demonstrating a pattern of bacterial colonization and maturation similar to in vivo subgingival biofilms. When the model and its methodology were standardized, the ETEP research group employed the validated in vitro biofilm model for testing in different applications. The evolution of this model is described in this manuscript, from the mere observation of biofilm growth and maturation on static models on hydroxyapatite or titanium discs, to the evaluation of the impact of dental implant surface composition and micro-structure using the dynamic biofilm model. This evolution was based on reproducing the ideal microenvironmental conditions for bacterial growth within a bioreactor and reaching the target surfaces using the fluid dynamics mimicking the salivary flow. The development of this relevant biofilm model has become a powerful tool to study the essential processes that regulate the formation and maturation of these important microbial communities, as well as their behavior when exposed to different antimicrobial compounds.

Peri-Implant Diseases: Diagnosis, Clinical, Histological, Microbiological Characteristics and Treatment Strategies. A Narrative Review

Since the use of dental implants is continuously increasing, it is imperative for dental practitioners to understand the nature and treatment of peri-implant diseases. The purpose of this manuscript is to comprehensively review peri-implant diseases, their characteristics, as well as their non-surgical and surgical treatment. To that end, the current literature was searched and a narrative review was conducted. It is essential that the case definitions described in the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions are used to diagnose and classify peri-implant health, peri-implant mucositis and peri-implantitis. While recent epidemiologic studies on peri-implant diseases exist, there is great heterogeneity in the definition of these conditions. Several risk factors and indicators are reported in the literature, with smoking and diabetes being the most universally accepted. In peri-implant mucositis, non-surgical treatment seems to be sufficient. However, for the treatment of peri-implantitis, a surgical approach, which includes open-flap debridement, apically positioned flap and guided bone regeneration, is considered more appropriate. A great variety of adjuncts to mechanical treatment have been reported with controversial results. Finally, studies comparing results from different peri-implantitis treatments are warranted in randomized controlled clinical trials in order to provide stronger evidence-based approaches.

Comparison between four different implant surface debridement methods: an in-vitro experimental study

BACKGROUND

Peri-implantitis treatment is a very challenging topic to discuss. What is certain is that preventive/supportive therapy plays a key-role in peri-implant tissues' health maintenance and non-surgical implant surface mechanical debridement remains one of the solid pillars in the therapeutic pathway. In this perspective, many surface decontaminating methods have been proposed and tested to remove hard and soft bacterial deposits. The aim of this study was to compare four different commonly used non-surgical implant debridement methods in terms of cleaning potential in vitro, using a peri-implant pocket-simulating model.

METHODS

Sixty-four dental implants were ink-stained and placed into a simulated peri-implant pocket. Samples were then divided into four groups and treated with different debridement methods: stainless-steel ultrasonic tip (PS), peek-coated ultrasonic tip (PI), sub-gingival air-polishing with erythritol powder (EHX) and sub-gingival air-polishing with glycine powder (GLY). For each treatment group, half of the samples were treated for 5 seconds and the other half for 45 seconds. High-resolution images were taken using a digital microscope and later analyzed with a light processing software for measuring the cleaned area percentage (ink-free). Two different images were captured for every sample: a first image with the implant positioned perpendicular to the microscope lenses (90°) and a second one with the implant placed with a 45° vertical angulation, with the smooth neck towards the ground. Percentage of removed ink was statistically modelled using a generalized linear mixed model with the implant as a random (clustering) factor.

RESULTS

A paired comparison between all treatments in terms of debridement potential (cleaned area percentage) was performed. In 5s and with 90° sample angulation EHX/PS comparison showed an odds ratio of 2.75 (P<0.001), PI/EHX an OR of 0.20 (P<0.001), GLY/PS an OR of 2.90 (P<0.001), PI/GLY an OR of 0.19 (P<0.001) and PI/PS an OR of 0.56 (P=0.105). With the same sample angulation and 45s treatment time, the OR was 6.97 (P<0.001) for EHX/PS comparison, 0.14 (P<0.001) for PI/EHX comparison, 4.99 (P<0.001) for GLY/PS, 0.19 (P<0.001) for PI/GLY and 0.95 for PI/PS (P =0.989). With 5s of treatment time and 45° sample angulation, EHX/PS comparison shows a 3.19 odds ratio (P<0.001), PI/EHX a 0.14 odds ratio (P<0.001), GLY/PS a 3.06 odds ratio (P<0.001), PI/GLY a 0.15 odds ratio (P<0.001) and PI/PS a 0.46 odds ratio (P=0.017). With the same sample angulation but 45s treatment time, EHX/PS comparison produced an odds ratio of 4.90 (P<0.001), PI/EHX an OR of 0.20 (P<0.001), GLY/PS an OR of 8.74 (P<0.001), PI/GLY an OR of 0.11 (P<0.001) and PI/PS an OR 0.96 of (P =0.996).

CONCLUSIONS

Among the four treatments considered, air-polishing therapy represents the best one in terms of ink removal from the implant surface. Furthermore, increasing the treatment time to 45 seconds, air-polishing resulted considerably more efficient.

High speed imaging of biofilm removal from a dental implant model using ultrasonic cavitation

OBJECTIVES

Current instruments cannot clean in between dental implant threads and effectively remove biofilm from the rough implant surface without damaging it. Cavitation bubbles have the potential to disrupt biofilms. The aim of this study was to see how biofilms can be disrupted using non-contact cavitation from an ultrasonic scaler, imaged inside a restricted implant pocket model using high speed imaging.

METHODS

Streptococcus sanguinis biofilm was grown for 7 days on dental implants. The implants were placed inside a custom made restricted pocket model and immersed inside a water tank. An ultrasonic scaler tip was placed 0.5mm away from the implant surface and operated at medium power or high power for 2s. The biofilm removal process was imaged using a high speed camera operating at 500 fps. Image analysis was used to calculate the amount of biofilm removed from the high speed images. Scanning electron microscopy was done to visualize the implant surface after cleaning.

RESULTS

Cavitation was able to remove biofilm from dental implants. More biofilm was removed at high power. Scanning electron microscopy showed that the implant surface was clean at the points where the cavitation was most intense. High speed imaging showed biofilm removal underneath implant threads, in areas next to the ultrasonic scaler tip.

SIGNIFICANCE

A high speed imaging protocol has been developed to visualize and quantify biofilm removal from dental implants in vitro. Cavitation bubbles from dental ultrasonic scalers are able to successfully disrupt biofilm in between implant threads.

Cleaning potential of different air abrasive powders and their impact on implant surface roughness

BACKGROUND

Implant surface roughness after air abrasive therapy has not been measured precisely in previous research. Debridement with air abrasion facilitates the mechanical removal of bacterial biofilms but may damage implant surfaces on a microscopic level.

PURPOSE

This study aimed to investigate the cleaning potential of various air abrasive powders and their effect on titanium implant surfaces.

MATERIALS AND METHODS

Twenty implants coated with red ink were inserted into three-dimensional printed circumferential bone defect models. Treatment was completed with three types of air abrasive powders: sodium bicarbonate (SB), glycine, and erythritol for 60 seconds. Water alone was used as control. The percentage of remaining ink was assessed using digital photography and graphic software. Implant surface topography/roughness was quantified using optical profilometry and examined via scanning electron microscopy. The microscopic analysis was performed at two implant areas: collar (Laser-Lok surface) and threads.

RESULTS

The cleaned surfaces (%, mean ± SD) after treatment with SB, glycine, and erythritol accounted for 49.3 ± 3.6%, 33.1 ± 1.2%, and 25.1 ± 0.7%, respectively. Statistically significant differences were found between all groups (P < .001). SB was the only powder that significantly increased the implant roughness (S_a ) on both the implant collar (1.53-2.10 μm) and threads (3.53-4.20 μm). Regardless of the abrasive powder used, the collar, emerging implant surfaces from the defect base, and surfaces beneath implants threads exhibited more post-treatment residual ink.

CONCLUSION

Large-sized powder showed the greatest cleaning capacity, but caused more alterations to the implant surface. Glycine and erythritol displayed no significant changes in surface roughness, however, demonstrated a limited ink removal capacity.

Cold atmospheric plasma is a viable solution for treating orthopedic infection: a review

Bacterial infection and antibiotic resistance are major threats to human health and very few solutions are available to combat this eventuality. A growing number of studies indicate that cold (non-thermal) plasma treatment can be used to prevent or eliminate infection from bacteria, bacterial biofilms, fungi and viruses. Mechanistically, a cold plasma discharge is composed of high-energy electrons that generate short-lived reactive oxygen and nitrogen species which further react to form more stable compounds (NO2, H2O2, NH2Cl and others) depending on the gas mixture and plasma parameters. Cold plasma devices are being developed for medical applications including infection, cancer, plastic surgery applications and more. Thus, in this review we explore the potential utility of cold plasma as a non-antibiotic approach for treating post-surgical orthopedic infections.

Decontamination methods to restore the biocompatibility of contaminated titanium surfaces

Purpose

The reaction of cells to a titanium implant depends on the surface characteristics of the implant which are affected by decontamination. The aim of this study was to evaluate the cytocompatibility of titanium disks treated with various decontamination methods, using salivary bacterial contamination with dental pellicle formation as an in vitro model.

Methods

Sand-blasted and acid-etched (SA) titanium disks were used. Three control groups (pristine SA disks [SA group]; salivary pellicle-coated SA disks [pellicle group]; and biofilm-coated, untreated SA disks [NT group]) were not subjected to any decontamination treatments. Decontamination of the biofilm-coated disks was performed by 14 methods, including ultrasonic instruments, rotating instruments, an air-powder abrasive system, a laser, and chemical agents. MG63 cells were cultured in the presence of the treated disks. Cell proliferation assays were performed on days 2 and 5 of cell culture, and cell morphology was analyzed by immunofluorescence and scanning electron microscopy (SEM). A vascular endothelial growth factor (VEGF) assay was performed on day 5 of culture.

Results

The cell proliferation assay revealed that all decontaminated disks, except for the 2 groups treated using a plastic tip, showed significantly less cell proliferation than the SA group. The immunofluorescence and SEM analyses revealed that most groups showed comparable cell density, with the exception of the NT group, in which the cell density was lower and bacterial residue was observed. Furthermore, the cells grown with tetracycline-treated titanium disks showed significantly lower VEGF production than those in the SA group.

Conclusions

None of the decontamination methods resulted in cytocompatibility similar to that of pristine SA titanium. However, many methods caused improvement in the biocompatibility of the titanium disks in comparison with the biofilm-coated, untreated titanium disks. This suggests that decontamination is indispensable for the treatment of peri-implantitis, even if the original biocompatibility cannot be restored.

Effects of air abrasive decontamination on titanium surfaces: A systematic review of in vitro studies

BACKGROUND

Air abrasion (AA) is one of the decontamination methods that have demonstrated promising results in treating peri-implant diseases.

PURPOSE

This systematic review aimed at evaluating the in vitro effect of AA on surface change, cleaning efficacy, and biocompatibility of titanium surfaces and at comparing it with other decontamination methods.

MATERIALS AND METHODS

A comprehensive search was conducted up to April 2018 using PubMed, Scopus, and Google Scholar databases to identify studies on the decontamination effect of AA. All types of titanium surfaces, abrasive powders, contaminated surfaces, and measuring methods were included.

RESULTS

Overall, 1502 articles were identified. After screening the titles and abstracts, and carefully reading the full-texts, 48 articles published between 1989 and 2018 were selected. AA was considered almost safe, particularly for the nonmodified surfaces. Nevertheless, harder powders such as sodium bicarbonate tended to damage the surface more than glycine. AA resulted in surface change similar to plastic curettes and Er: YAG lasers. Regarding the cleaning efficacy, there was no significant difference between glycine and sodium bicarbonate, but different mixtures of calcium phosphate, hydroxyapatite, and erythritol were superior to glycine. AA was superior or equal to all other decontamination methods in cleaning. Regarding biocompatibility, AA was more successful in preserving biocompatibility for noncontaminated surfaces compared with contaminated surfaces and when used with erythritol and osteoinductive powders.

CONCLUSIONS

AA can efficiently remove contamination without serious damage to the surface. The main drawback of the AA method seems to be its limitation in restoring the biocompatibility of the surface.

Effects of statins on multispecies oral biofilm identify simvastatin as a drug candidate targeting Porphyromonas gingivalis

BACKGROUND

Statins effectively reduce risk of cardiovascular-related morbidity and mortality in patients with hyperlipidemia, hypertension, or type 2 diabetes. In addition to lowering cholesterol levels, several studies have attributed statins with immunomodulatory and bactericidal properties. Therefore, the aim of this study was to investigate statins' antimicrobial activity against periodontal homeostasis bacteria.

METHODS

Statin effect on bacterial growth was tested using planktonic monocultures and multibacterial biofilms. The latter consisted of five microbial species (Porphyromonas gingivalis, Fusobacterium nucleatum, Actinomyces naeslundii, Tannerella forsythia, and Streptococcus gordonii) associated with dysbiosis of the oral microbiota underlying establishment and perpetuation of periodontitis.

RESULTS

All four tested statins efficiently inhibited P. gingivalis growth and significantly decreased the cumulative bacterial load in developing and established biofilms. Simvastatin was most efficient and decreased P. gingivalis counts more than 1,300-fold relative to the control.

CONCLUSIONS

These findings suggest that similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microbiome from a dysbiotic to a more homeostatic one. Simvastatin, being highly effective against P. gingivalis while not affecting commensal microbiota, possesses many properties qualifying it as a potential adjunctive treatment for chronic periodontitis. Further studies are needed to evaluate whether similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microflora from dysbiotic to a more homeostatic one.

Clinical evaluation of non-surgical cleaning modalities on titanium dental implants during maintenance care: a 1-year follow-up on prosthodontic superstructures

OBJECTIVES

To investigate tissue health around implants with newly attached superstructures over 12 months of preventive maintenance appointments and instrumentation when necessary.

MATERIAL AND METHODS

In a randomized, split-mouth study 32 implants (8 participants with 4 implants each) received followed-up care every 3 months after superstructure attachment. Implants and superstructures were randomly assigned to four treatment groups and treated if necessary: (1) titanium curettes (TC), (2) stainless steel ultrasonic tip (PS), (3) erythritol air-polishing powder (EP), or (4) rubber cup polishing (CON). Probing depths (PDs), bleeding on probing (BOP), modified gingival (mucosal) bleeding index (GBI) around implants, and full-mouth Plaque Control Record (PCR) were measured every 3 months. Clinical attachment levels (CALs) and height of keratinized mucosa (KM)/gingival margins (GMs) for implants/teeth and PD, BOP, and GBI for teeth were documented at baseline, 6 months, and 12 months. Matrix metalloproteinase 8 (MMP-8) and periopathogens were measured at baseline and 12 months.

RESULTS

Participants exhibited minimal signs of periodontal inflammation with statistically significant PD improvement (3.0 ± 0.2 to 2.8 ± 0.3 mm; p = 0.022) and overall CAL (4.3 ± 0.8 to 4.0 ± 0.7 mm; p = 0.048) after 1 year. Implants showed no statistically significant differences (p > 0.05) between or within groups at baseline or 12 months for any parameter, except MMP-8 decreased significantly for PS (14.50 ± 17.58 to 4.63 ± 7.56 ng; p = 0.044), and after 12 months, PCR showed a significant difference between TC and PS (p = 0.018).

CONCLUSIONS

Treatment was necessary as inflammation was observed around newly placed superstructures within the first year of maintenance care. All tested treatment modalities yielded comparable clinical improvements.

CLINICAL RELEVANCE

Early assessment and diagnosis of mucositis and regular maintenance can promote long-lasting implant health.

Biofilm Removal and Bacterial Re-Colonization Inhibition of a Novel Erythritol/Chlorhexidine Air-Polishing Powder on Titanium Disks

Air-polishing with low abrasiveness powders is fast arising as a valid and mini-invasive instrument for the management of biofilm colonizing dental implants. In general, the reported advantage is the efficient removal of plaque with respect to the titanium integrity. In the present study, we evaluated the in situ plaque removal and the preventive efficacy in forestalling further infection of an innovative erythritol/chlorhexidine air-polishing powder and compared it with sodium bicarbonate. Accordingly, two peri-implantitis-linked biofilm formers, strains Staphylococcus aureus and Aggregatibacter actinomycetemcomitans, were selected and used to infect titanium disks before and after the air-polishing treatment to test its ability in biofilm removal and re-colonization inhibition, respectively. Biofilm cell numbers and viability were assayed by colony-forming unit (CFU) count and metabolic-colorimetric (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) (XTT) assay. Results demonstrated that air-polishing performed with either sodium bicarbonate or erythritol/chlorhexidine was effective in reducing bacteria biofilm viability and number on pre-infected specimens, thus showing a similar ability in counteracting existing infection in situ; on the other hand, when air-polished pre-treated disks were infected, only erythritol/chlorhexidine powder showed higher post-treatment biofilm re-growth inhibition. Finally, surface analysis via mechanical profilometry failed to show an increase in titanium roughness, regardless of the powder selected, thus excluding any possible surface damage due to the use of either sodium bicarbonate or erythritol/chlorhexidine.

Simulated damage of two implant debridement methods: Nonsurgical approach with Teflon and stainless steel hand scalers

BACKGROUND

Mechanical scaling is the most common treatment of periodontal and peri-implant tissue infections.

AIMS

This study aimed to evaluate the effect of mechanical prophylactic therapy on the residual stresses in the implant and hand scaler.

SETTINGS AND DESIGN

For finite-element analysis, an implant-supported prosthesis was created using modeling software with 3 mm of exposed threads. For simulation of a prophylactic mechanical debridement, the active face of the shank was disposed of in contact with the last thread exposed at a 90° angle.

MATERIALS AND METHODS

In the analysis software, the contacts were defined as rough between the instrument and the implant. The cortical bone was fixed and a load of 10 N was applied to the instrument cable. Two simulations were performed according to the instrument material: stainless steel or Teflon. Von-Mises results were obtained.

STATISTICAL ANALYSIS USED

No statistical test was used, but, the 500 higher stress peaks in the implant and in the instrument were analyzed for qualitative comparison.

RESULTS

Mechanical prophylactic therapy generates higher residual stress on the implant with a stainless steel instrument. There was no difference between the materials for the active tip of the instrument, and the active portion of the shank was the region which concentrated more stress.

CONCLUSIONS

It is suggested that hand scalers in Teflon are less damaging to the implant, but more susceptible to deformation and possible early failures.

Influence of scaling procedures on the integrity of titanium nitride coated CAD/CAM abutments

PURPOSE

To determine the extent of treatment traces, the roughness depth, and the quantity of titanium nitride (TiN) removed from the surface of CAD/CAM abutments after treatment with various instruments.

MATERIALS AND METHODS

Twelve TiN coated CAD/CAM abutments were investigated for an in vitro study. In the test group (9), each abutment surface was subjected twice (150 g vs. 200 g pressure) to standardized treatment in a simulated prophylaxis measure with the following instruments: acrylic scaler, titanium curette, and ultrasonic scaler with steel tip. Three abutments were used as control group. Average surface roughness (Sa) and developed interfacial area ratio (Sdr) of treated and untreated surfaces were measured with a profilometer. The extent of treatment traces were analyzed by scanning electron microscopy.

RESULTS

Manipulation with ultrasonic scalers resulted in a significant increase of average surface roughness (Sa, P<.05) and developed interfacial area ratio (Sdr, P<.018). Variable contact pressure did not yield any statistically significant difference on Sa-values for all instruments (P=.8). Ultrasonic treatment resulted in pronounced surface traces and partially detachment of the TiN coating. While titanium curettes caused predominantly moderate treatment traces, no traces or detectable substance removal has been determined after manipulation with acrylic curettes.

CONCLUSION

Inappropriate instruments during regular plaque control may have an adverse effect on the integrity of the TiN coating of CAD/CAM abutments. To prevent defects and an increased surface roughness at the transmucosal zone of TiN abutments, only acrylic scaling instruments can be recommended for regular maintenance care.

Clinical and laboratory evaluation of the effects of different treatment modalities on titanium healing caps: a randomized, controlled clinical trial

OBJECTIVES

The objective of this study is to evaluate the effects of treatment modalities on titanium surface characteristics and surrounding tissues.

MATERIALS AND METHODS

Eighteen participants each had four titanium healing caps (HC) attached to four newly inserted implants. After healing, each HC was randomly assigned to either (1) titanium curettes (TC), (2) stainless steel ultrasonic tip (PS), (3) erythritol air-polishing powder (EP), or (4) only rubber cup polishing (CON). Probing depths (PD), bleeding on probing (BOP), matrix metalloproteinase 8 (MMP-8), and periopathogens were recorded before and 3 months following instrumentation. After final assessments, HCs were removed, cleaned, and subjected to (a) bacterial colonization (Streptococcus gordonii, 24 h; mixed culture, 24 h) and (b) gingival fibroblasts (5 days). HC surfaces were analyzed with a scanning electron microscope (SEM).

RESULTS

No significant differences between the groups were evident before or after instrumentation for PD and BOP (except TC showed a significant decrease in PD; p = 0.049). MMP-8 levels and bacterial loads were always very low. MMP-8 decreased further after instrumentation, while bacteria levels showed no change. No significant differences (p > 0.05) were evident in bacterial colonization or fibroblast attachment. A comparison of the overall mean SEM surface roughness scores showed a significant difference between all groups (p < 0.0001) with the lowest roughness after EP.

CONCLUSIONS

All treatments performed yielded comparable outcomes and may be implemented safely.

CLINICAL RELEVANCE

Clinicians may fear implant surface damage, but all instrumentation types are safe and non-damaging. They can be implemented as needed upon considering the presence of staining and soft and hard deposits.

Influence on proliferation and adhesion of human gingival fibroblasts from different titanium surface decontamination treatments: An in vitro study

OBJECTIVES

To investigate the effects of different decontamination treatments on microstructure of titanium (Ti) surface as well as proliferation and adhesion of human gingival fibroblasts (HGFs).

MATERIAL AND METHODS

Ti discs with machined (M) and sand blasted, acid etched (SAE) surfaces were treated with five different decontamination treatments: (1) stainless steel curette (SSC), ultrasonic system with (2) straight carbon fiber tip (UCF) or (3) metal tip (UM), (4) rotating Ti brush (RTB), and (5) Er:YAG laser (30 mJ/pulse at 30 Hz). Surface roughness was analyzed under optical interferometry. HGFs were cultured on each disc. Proliferation and adhesive strength were analyzed. qRT-PCR and ELISA were performed to detect the RNA and protein expression of FAK, ITGB1, COL1A1, and FN1 respectively from different Ti surfaces.

RESULTS

Surface roughness increased on M surface. Proliferation, adhesive strength and gene expression were higher on M surface than SAE surface. Decontamination treatments affected surface parameters significantly (P < 0.001), making M surface less smooth while SAE surface became less rough. SSC, UCF, UM and RTB decreased proliferation on M surfaces significantly (P < 0.05). UCF, RTB and laser increased proliferation on SAE surface significantly (P < 0.05). UM decreased adhesive strength on M surface significantly and laser increased adhesive strength on SAE surface significantly (P < 0.05). Gene expression increased with time and was altered by decontamination treatments significantly (P < 0.001).

CONCLUSIONS

Decontamination treatments influence surface roughness and cell behavior of HGFs. Laser might be an optimal decontamination treatment which has the least negative effect on M surface and the most positive effect on SAE surface.

Antimicrobial Effects of Three Different Treatment Modalities on Dental Implant Surfaces

Resolution of peri-implant inflammation and re-osseointegration of peri-implantitis affected dental implants seem to be dependent on bacterial decontamination. The aims of the study were to evaluate the antimicrobial effects of 3 different instrumentations on a micro-textured dental implant surface contaminated with an avirulent or a virulent Porphyromonas gingivalis strain and to determine alterations to the implant surface following instrumentation. Forty-five dental implants (Straumann SLA) were allocated to 3 treatment groups: Er:YAG laser, chitosan brush, and titanium curette (10 implants each) and a positive (10 implants) and a negative (5 implants) control. Each treatment group and the positive control were split into subgroups of 5 implants subsequently contaminated with either the avirulent or virulent P. gingivalis strain. The antimicrobial effect of instrumentation was evaluated using checkerboard DNA-DNA hybridization. Implant surface alterations were determined using a light interferometer. Instrumentation significantly reduced the number of attached P. gingivalis ( P < .001) with no significant differences among groups ( P = .310). A significant overall higher median score was found for virulent compared with avirulent P. gingivalis strains ( P = .007); the Er:YAG laser uniquely effective removing both bacterial strains. The titanium curette significantly altered the implant surface micro-texture. Neither the Er:YAG laser nor the chitosan brush significantly altered the implant surface. The 3 instrumentations appear to have a similar potential to remove P. gingivalis. The titanium curette significantly altered the microstructure of the implant surface.