Reactive lesions of peri-implant mucosa associated with titanium dental implants: a report of 2 cases

Chronic exposure to TiO2 micro- and nano particles: A biochemical and histopathological experimental study

The aim of this work was to analyze the effects of long-term exposure to titanium dioxide (TiO2) micro- (MPs) and nanoparticles (NPs) (six and 12 months) on the biochemical and histopathological response of target organs using a murine model. Male Wistar rats were intraperitoneally injected with a suspension of TiO2 NPs (5 nm; TiO2-NP5 group) or MPs (45 μm; TiO2-NP5 group); the control group was injected with saline solution. Six and 12 months post-injection, titanium (Ti) concentration in plasma and target organs was determined spectrometrically (ICP-MS). Blood smears and organ tissue samples were evaluated by light microscopy. Liver and kidney function was evaluated using serum biochemical parameters. Oxidative metabolism was assessed 6 months post-injection (determination of superoxide anion by nitroblue tetrazolium (NBT) test, superoxide dismutase (SOD) and catalase (CAT), lipid peroxidation, and paraoxonase 1). Titanium (Ti) concentration in target organs and plasma was significantly higher in the TiO2-exposed groups than in the control group. Histological evaluation showed the presence of titanium-based particles in the target organs, which displayed no structural alterations, and in blood monocytes. Oxidative metabolism analysis showed that TiO2 NPs were more reactive over time than MPs (p < .05) and mobilization of antioxidant enzymes and membrane damage varied among the studied organs. Clearance of TiO2 micro and nanoparticles differed among the target organs, and lung clearance was more rapid than clearance from the lungs and kidneys (p < .05). Conversely, Ti concentration in plasma increased with time (p < .05). In conclusion, neither serum biochemical parameters nor oxidative metabolism markers appear to be useful as biomarkers of tissue damage in response to TiO2 micro- and nanoparticle deposits at chronic time points.

Investigating the influence of titanium particle size and concentration on osteogenic response of human osteoblasts - in vitro study

Purpose

The purpose of this study was to investigate the correlation between the size and concentration of titanium particles and the osteogenic response of human osteoblasts (HOB).

Materials and Methods

Different concentrations of titanium dioxide nano- and micro-particles were prepared and their biocompatibility on HOBs was analyzed using XTT assay. The changes in the actin cytoskeletal organization were studied by confocal laser scanning microscopy. The generation of intracellular reactive oxygen species (ROS) by HOBs after exposure to titanium dioxide particles was analyzed using ROS assay. Besides, the osteogenic potential represented by alkaline phosphatase activity, osteoprotegerin, macrophage colony stimulating factor levels, and biomineralization were analyzed.

Results

Short-term interaction of titanium dioxide nano- and micro-particles did not induce toxicity to HOBs. However, cells treated with 100 μg/mL titanium dioxide nano- and micro-particles demonstrated higher ROS generation compared to control. Besides, cells treated with 100 μg/mL titanium dioxide nanoparticles showed higher alkaline phosphatase activity, osteoprotegerin, macrophage colony stimulating factor levels and biomineralization compared to titanium dioxide microparticles.

Conclusion

Collectively, the study found titanium dioxide nanoparticles to be more biocompatible than microparticles providing an insight into the capability of nanostructures in supporting osteoblast differentiation and its plausibility in biomedical applications.

Emerging factors affecting peri-implant bone metabolism

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

Oral Pyogenic Granuloma: A Narrative Review

Pyogenic granuloma (PG) is a benign vascular lesion found predominantly in the oral cavity. Characterized by rapid growth and propensity to bleed, PG presents diagnostic challenges due to its similarity and alarming proliferation. This narrative review synthesizes current knowledge on the epidemiology, etiopathogenesis, clinical manifestations, and management of oral PG, with emphasis on recent advances in diagnostic and therapeutic approaches. The epidemiology of the injury is meticulously analyzed, revealing a higher incidence in women and a wide range of ages of onset. It delves into the etiopathogenesis, highlighting the uncertainty surrounding the exact causal factors, although historical attributions suggest an infectious origin. It exhaustively analyzes the clinical and histopathological aspects of oral PG, offering information on its various presentations and the importance of an accurate diagnosis to guide effective treatment. It details treatment strategies, emphasizing the personalized approach based on individual patient characteristics. This comprehensive review consolidates current knowledge on oral PG, highlighting the need for further research to clarify its pathogenesis and optimize treatment protocols.

Primary stability of implant placement and loading related to dental implant materials and designs: A literature review

A variety of implant placement and loading protocols are identified, ranging from immediate implant placement on the day of extraction to delayed placement for at least 6 months after complete healing. The method of assessment of implant placement and loading plays an important role in the implantation. The expected clinical outcomes depend largely on multiple factors, such as the macroscopic design of the implant, surgical technique, and the quality and quantity of local bone in contact with the implant, which would be described in detail. The purpose of this literature review was to explore the relationship between the factors influencing the implant placement stability and implant design. By understanding the original appearance of implant design and the stability requirements of implant placement, it is hoped that more research in the future can meet the needs of dentists and patients.

The management of an oral pyogenic granuloma around osseointegrated dental implants

INTRODUCTION

Oral pyogenic granulomas (PGs) presenting in association with dental implants are uncommon occurrences. While tooth-associated PGs are well-documented in the literature, there are only seven case reports with biopsy-confirmed diagnoses of PG related to dental implants. This case report details the treatment of an intraoral PG related to dental implants that had been osseointegrated and asymptomatic for 10 years.

CASE PRESENTATION

A 39-year-old female presented with a hyperplastic erythematous mass that encompassed the dental implants in the position of the maxillary central incisors. Surgical exploration of the site revealed nonintegrated, particulate bone material distributed throughout the peri-implant tissues approximating the granuloma. Treatment involved surgical excision of the lesion, elimination of all nonintegrated bone material, and implant surface debridement. Laser therapy was later used to manage a recurrence. Histology of the biopsied tissue confirmed the diagnosis of PG and described the presence of multiple exogenous, refractile, particulate materials in the specimen.

CONCLUSION

The combination of surgical excision, implant debridement, and conservative laser therapy resulted in the elimination of a dental implant-related PG and successful soft tissue management. The localized presence of nonintegrated particulate bone material surrounding the granuloma appears to have functioned as a chronic irritant to the peri-implant soft tissues over time and is likely, along with oral bacteria, the primary etiological agents.

KEY POINTS

Why is this case new information? There is a paucity of reports describing the management of dental implant-related pyogenic granulomas especially in the esthetic region. The present case demonstrates that particulate bone materials used in guided bone regeneration have the capacity to behave as a low-grade irritant to the gingival tissues. It also demonstrates the successful elimination of the tissues and management of the peri-implant soft tissues for an esthetic result. What are the keys to successful management of this case? The key to successful management of this case was adequate removal of the exogenous irritant, proper implant surface debridement, and decontamination and adequate gingivoplasty to remove all residual hyperplastic granulomatous tissues. Additionally, patient education and appropriate oral hygiene instructions were important to proper healing and maintenance of the area. What are the primary limitations to success in this case? The ambiguity of the clinical boundaries of PGs makes it challenging to guarantee complete excision beyond the base of the lesion, leading to recurrence.

Dental Implants and Implant Coatings: A Focus on Their Toxicity and Safety

Dental implants are medical devices that are surgically inserted into the patient's jawbone by an orthodontist to act as roots of missing teeth. After the implantation, the maxilla or mandible integrates with the surface of the dental implant. This process, called "osseointegration," is an important period to ensure the long-term use of dental implants and prevent implant failures. Metal implants are the most used implant materials. However, they have disadvantages such as corrosion, metal ion release from metal implant surfaces and associated toxicity. To avoid these adverse effects and improve osseointegration, alternative dental implant materials such as ceramics, polymers, composites, and novel surface modification technologies have been developed. The safety of these materials are also of concern for toxicologists. This review will give general information about dental implant materials, osseointegration and successful implantation process. Moreover, we will focus on the new surface coatings materials for of dental implants and their toxicity and safety concerns will be discussed.

Diagnostic tests for titanium hypersensitivity in implant dentistry: a systematic review of the literature

PURPOSE

There are rising concerns about titanium hypersensitivity reaction regarding dental endosseous implants. This review aims to summarize and compare the validity and reliability of the available dermatological and laboratory diagnostic tests regarding titanium hypersensitivity. The following PICO design was used: In Patients with titanium dental implants (P) does epicutaneous testing (ECT) (I), compared to lymphocyte transformation test (LTT) or Memory Lymphocyte Immunostimulation Assay (MELISA) (C) detect hypersensitivity reactions (O)? A literature search was performed including all studies dealing with this topic. Studies regarding orthopedic implants were excluded.

METHODS

Three databases (MEDLINE PubMed, Cochrane Library, SciELO) were screened for suitable studies and an additional manual search was also performed. Literature regarding hypersensitivity reactions in orthopedic implants, hypersensitivity reactions regarding implants not related to dental or maxillofacial surgery, animal studies and in vitro studies were excluded. A quality assessment of all selected full-text articles was performed. Randomized, controlled trials were evaluated with the Cochrane Risk of Bias Tool I. Cohort studies were assessed according to the New Castle-Ottawa Scale and case series according to Moga et al. (Development of a quality appraisal tool for case series studies using a modified Delphi technique. 2012).

RESULTS

10 studies were included in the quantitative synthesis and available for the endpoint diagnostics of intolerance reactions to titanium dental implants: 2 clinical studies, 7 cohort studies and 1 case series. The potential for bias (internal validity) for these studies was overall rated as high.

CONCLUSIONS

The study of the available literature regarding ECT and MELISA or LTT in patients with suspected titanium hypersensitivity showed inconsistent results in terms of reliability and validity and thus, those tests should be regarded cautiously. There is strong evidence that titanium hypersensitivity in dental implants is associated with innate immunity: unspecific pro-inflammatory responses due to particle induced hyperreactivity of macrophages or toxicological responses especially towards nanoparticles rather than activation of the adaptive immune system. Therefore, tests detecting allergies do not seem expedient and inflammatory clinical signs should be regarded as leading parameters.

Clinical and Radiographic Outcomes of Zirconia Dental Implants-A Clinical Case Series Study

The purpose of this clinical series was to evaluate the clinical and radiographic outcomes of 20 zirconia dental implants, with a minimum follow-up of two years. Patients with at least one zirconia dental implant were included, with a mean follow-up of 34.05 months. The patient complaints such as pain and foreign body sensation, as well as clinical parameters including peri-implant infections with suppuration, implant mobility, gingival index (GI), modified plaque index (mPI), modified sulcus bleeding index (mBI), probing depth (PD) and radiological distance between the implant shoulder to the closest mesial and distal bone-to-implant contact (BIC), were assessed. All zirconia implants were successfully integrated without any pain or foreign body sensation. No mobility was detected in any of the 20 implants. Clinical examination revealed a mean PD of 2.56 mm and a radiological mean distance between the implant shoulder and the initial site of visible bone-to-implant contact (BIC) of 1.44 mm. In addition, GI, mPI and mBI indicated minimal to no inflammation. Results obtained from this series suggest that one-piece zirconia dental implants achieve good clinical and radiographic outcomes over a mean follow-up of 34 months and may be deemed a good option in patients with favorable bone conditions.

A Biocompatible Ultrananocrystalline Diamond (UNCD) Coating for a New Generation of Dental Implants

Implant therapy using osseointegratable titanium (Ti) dental implants has revolutionized clinical dental practice and has shown a high rate of success. However, because a metallic implant is in contact with body tissues and fluids in vivo, ions/particles can be released into the biological milieu as a result of corrosion or biotribocorrosion. Ultrananocrystalline diamond (UNCD) coatings possess a synergistic combination of mechanical, tribological, and chemical properties, which makes UNCD highly biocompatible. In addition, because the UNCD coating is made of carbon (C), a component of human DNA, cells, and molecules, it is potentially a highly biocompatible coating for medical implant devices. The aim of the present research was to evaluate tissue response to UNCD-coated titanium micro-implants using a murine model designed to evaluate biocompatibility. Non-coated (n = 10) and UNCD-coated (n = 10) orthodontic Ti micro-implants were placed in the hematopoietic bone marrow of the tibia of male Wistar rats. The animals were euthanized 30 days post implantation. The tibiae were resected, and ground histologic sections were obtained and stained with toluidine blue. Histologically, both groups showed lamellar bone tissue in contact with the implants (osseointegration). No inflammatory or multinucleated giant cells were observed. Histomorphometric evaluation showed no statistically significant differences in the percentage of BIC between groups (C: 53.40 ± 13% vs. UNCD: 58.82 ± 9%, p > 0.05). UNCD showed good biocompatibility properties. Although the percentage of BIC (osseointegration) was similar in UNCD-coated and control Ti micro-implants, the documented tribological properties of UNCD make it a superior implant coating material. Given the current surge in the use of nano-coatings, nanofilms, and nanostructured surfaces to enhance the biocompatibility of biomedical implants, the results of the present study contribute valuable data for the manufacture of UNCD coatings as a new generation of superior dental implants.

Effect of the Nature of the Particles Released from Bone Level Dental Implants: Physicochemical and Biological Characterization

The placement of bone–level dental implants can lead to the detachment of particles in the surrounding tissues due to friction with the cortical bone. In this study, 60 bone–level dental implants were placed with the same design: 30 made of commercially pure grade 4 titanium and 30 made of Ti6Al4V alloy. These implants were placed in cow ribs following the company’s placement protocols. Particles detached from the dental implants were isolated and their size and specific surface area were characterized. The irregular morphology was observed by scanning electron microscopy. Ion release to the medium was determined at different immersion times in physiological medium. Cytocompatibility studies were performed with fibroblastic and osteoblastic cells. Gene expression and cytokine release were analysed to determine the action of inflammatory cells. Particle sizes of around 15 μM were obtained in both cases. The Ti6Al4V alloy particles showed significant levels of vanadium ion release and the cytocompatibility of these particles is lower than that of commercially pure titanium. Ti6Al4V alloy presents higher levels of inflammation markers (TNFα and Il–1β) compared to that of only titanium. Therefore, there is a trend that with the alloy there is a greater toxicity and a greater pro-inflammatory response.

Analysis of Torque Maintenance and Fracture Resistance after Fatigue in Retention Screws Made of Different Metals for Screw-Retained Implant-Borne Prosthesis Joints

Purpose

The aim was to evaluate the effect of different metallic alloys used in the manufacture of retention screws for universal cast to long abutment (UCLA) abutments for external hexagon (HE) and Morse taper (MT) connection implants, as well as of mechanical cycling on torque maintenance and fracture resistance through electromechanical fatigue testing by mastication followed by compression testing.

Methods

Sixty implants were used, 30 MT and 30 HE, with their respective titanium UCLA abutments and retention screws of 5 different materials (n = 6): Ti cp grade 2, Ti cp grade 4, Ti cp grade 4 hard, Ti grade 5—Ti6Al4V and surgical steel (DSP® Biomedical). The assemblies were positioned in an electromechanical masticatory fatigue testing machine. The fracture strength test was performed by compression testing in a universal testing machine EMICDL-200.

Results

The cycled screws and new screws of each alloy group for each connection type were evaluated, obtaining the maximum force (FM), in order to verify the effect of mechanical cycling. The data were tabulated and submitted to appropriate statistical analysis (α = 0.05).

Conclusion

It was concluded that for the MT, the alloy with the best performance was steel, both in the maintenance of torque and in the compression test, and cycling negatively influenced the maintenance of preload for this connection. The alloy material did not influence torque maintenance for HE. The new screws that were subjected to EMIC showed higher strength. The alloy with the lowest strength was Ti grade 2.

Titanium Allergy Caused by Dental Implants: A Systematic Literature Review and Case Report

(1) Background: Hypersensitivity reactions to metals may arise in predisposed patients chronically exposed to metallic materials, including dental implants made of titanium alloys. The purpose of this article was to systematically review titanium allergy manifestations in patients treated with dental implants and report a clinical case; (2) Methods: A systematic electronic search was performed for articles published in the English language until July 2021. The following eligibility criteria were adopted: (1) Population: individuals undergoing titanium and/or titanium alloy implant-supported rehabilitations; (2) Exposure: peri-implant soft tissue reactions attributable to implant insertion; (3) Outcome: evidence of titanium allergy, diagnostic methods, and forms of resolution; (3) Results: The included studies, in summary, presented evidence that titanium should not be considered an inert material, being able to trigger allergic reactions, and may be responsible for implant failure. A 55-year-old male patient received 3 implants in the posterior region of the left mandible and presented an epulis-like lesion developed from the peri-implant mucosa. The immunohistochemical analysis of the biopsy specimen confirmed the initial diagnosis of allergic reaction to titanium; (4) Conclusions: Although the evidence is weak, and titanium allergy has a low incidence, hypersensitivity reactions should not be underestimated. A rapid and conclusive diagnosis is mandatory to prevent further complications.

KRAS Mutation in an Implant-associated Peripheral Giant Cell Granuloma of the Jaw: Implications of Genetic Analysis of the Lesion for Treatment Concept and Surveillance

The aim of this case report was to detail diagnosis and therapy in a case of implant-associated peripheral giant cell granuloma (IA-PGCG) of the jaw. Case Report: The 41-year-old female attended the outpatient clinic for treatment of recurrent mandibular IA-PGCG. The lesion was excised and the defect was closed with a connective tissue graft of the palate. Healing of oral defects was uneventful, and no local recurrence has occurred during a follow-up of 7 months. Genetic examination of the lesion identified a somatic mutation in KRAS. Conclusion: The lesions are assessed as reactive-inflammatory changes in the mucous membrane of the oral cavity. The cause of the lesion is unknown. KRAS mutations are commonly found in various cancer tissues, but also in germline and mosaic RASopathies. Recently, KRAS mutations have been identified in several IA-PGCG. The clinical course of a frequently locally recurring lesion gives rise to the assumption that lesions of this type show characteristics known in benign neoplasms.

The effect of nanoparticles of cobalt-chromium on human aortic endothelial cells in vitro

Despite advances in stent technology for vascular interventions, in-stent restenosis (ISR) remains a main complication. The corrosion of cobalt-chromium (CoCr) alloy coronary stents has been identified to be associated with ISR, whereas its role in ISR has not been elucidated. In the current work, CoCr nanoparticles, simulated corrosion products of CoCr alloy, were used to investigate their effect on the endothelial cells. It has been demonstrated that the cell viability declines and the cell membrane is damaged, indicating the cytotoxicity of CoCr nanoparticles. The expression of GRP78, CHOP, and cleaved-caspase12 proteins has increased when exposed to CoCr nanoparticles, suggesting that CoCr nanoparticles induced cell apoptosis through endoplasmic reticulum (ER) stress-mediated apoptotic pathway. An increased release of adhesion and inflammatory mediators was also induced by CoCr nanoparticles, including ICAM-1, VCAM-1, IL-1β, IL-6, and TNF-α. Our results demonstrated that CoCr nanoparticles could trigger apoptosis, adhesion, and inflammation. These findings indicated potential damaging effects of CoCr nanoparticles on the vascular endothelium, which suggested corrosion of CoCr alloy may promote the progression and development of ISR.

An analysis of the prevalence of peripheral giant cell granuloma and pyogenic granuloma in relation to a dental implant

Background

The aim of the present investigation was to evaluate the literature recurrence of peripheral giant cell granuloma and pyogenic granuloma associated with dental implants. It’s important to know the characteristics present in these lesions and possible effects on the prognosis of dental implants.

Methods

An electronic search without time restrictions was done in the databases: PubMed/Medline. With the keywords "Granuloma" OR "Granuloma, Giant Cell" OR "peripheral giant cell" OR "Granuloma, Pyogenic” AND "Dental implants" OR "Oral implants”.

Results

After applying the inclusion and exclusion criteria, a total of 20 articles were included, which reported 32 lesions (10 pyogenic granulomas, 21 peripheral giant cell granulomas and one peripheral giant cell granuloma combined with peripheral ossifying fibroma, all associated with implants). According to our review, these lesions are more frequent in males and in the posterior region of the mandible. Both excision and curettage of the lesion, compared to only excision, presented similar recurrences (40%). Explantation of the implant was performed in 41% of cases without additional recurrences. The results are not statistically significant when comparing one lesion to the other in terms of explantation (p = 0.97), recurrence (p = 0.57) or bone loss (p = 0.67).

Conclusions

The main therapeutic approach is tissue excision. The lesions show a high recurrence rate (34.4%), which often requires explantation of the associated implant. This recurrence rate is not affected by curettage after excision.

Effect of guide sleeve material, region, diameter, and number of times drills were used on the material loss from sleeves and drills used for surgical guides: An in vitro study

STATEMENT OF PROBLEM

How material loss from sleeves and drills is affected when different guide sleeve materials and different sizes of implant drills are used for different regions of surgical guides is unclear.

PURPOSE

The purpose of this in vitro study was to compare the amount of material loss from different guide sleeves (zirconia and cobalt-chromium) and drills of different diameters during osteotomy preparation in different regions.

MATERIAL AND METHODS

Three tooth-supported surgical guides with sleeve holes positioned in the first premolar and second molar sites were prepared. Guide sleeves (Ø 2.20 mm, 3.40 mm, and 4.05 mm) were milled from zirconia (n=60) and cobalt-chromium (n=60) blocks. A total of 12 titanium nitride-coated stainless steel twisted drills (n=6 per sleeve material) of different diameters (Ø 2.00, 3.20, 3.85 mm) were used with corresponding sleeves during the drilling. The weight loss from the drills and the volume loss from the guide sleeves after drilling were analyzed by using multiple linear mixed effect models (α=.05).

RESULTS

According to the 4-way ANOVA for volume loss from sleeves, no significant interaction was found among the 4 main effects (number of times a drill was used, region, diameter, and material), but interactions between the number of times a drill was used and diameter (P=.001) and between the number of times the drill was used and material were significant (P<.001). For weight loss from the drills, a significant interaction was detected between the number of times the drill was used and diameter (P=.024).

CONCLUSIONS

Less sleeve material was lost when zirconia sleeves were used. All sleeves had more material loss in the molar region than in the premolar region. The diameter had varying effects on the amount of material loss from drills and sleeves. The sleeve material and the region did not affect the material loss from drills.

Peri-implantitis is not periodontitis: Scientific discoveries shed light on microbiome-biomaterial interactions that may determine disease phenotype

Peri-implantitis is an immune-mediated biological complication that is attributed to bacterial biofilms on the implant surface. As both periodontitis and peri-implantitis have similar inflammatory phenotypes when assessed cross-sectionally, treatment protocols for peri-implantitis were modeled according to those used for periodontitis. However, lack of efficacy of antimicrobial treatments targeting periodontal pathogens coupled with recent discoveries from open-ended microbial investigation studies create a heightened need to revisit the pathogenesis of peri-implantitis compared with that of periodontitis. The tale of biofilm formation on intraoral solid surfaces begins with pellicle formation, which supports initial bacterial adhesion. The differences between implant- and tooth-bound biofilms appear as early as bacterial adhesion commences. The electrostatic forces and ionic bonding that drive initial bacterial adhesion are fundamentally different in the presence of titanium dioxide or other implant alloys vs mineralized organic hydroxyapatite, respectively. Moreover, the interaction between metal surfaces and the oral environment leads to the release of implant degradation products into the peri-implant sulcus, which exposes the microbiota to increased environmental stress and may alter immune responses to bacteria. Clinically, biofilms found in peri-implantitis are resistant to beta-lactam antibiotics, which are effective against periodontal communities even as monotherapies and demonstrate a composition different from that of biofilms found in periodontitis; these facts strongly suggest that a new model of peri-implant infection is required.

Titanium dental implant-related pathologies: A retrospective histopathological study

OBJECTIVES

To perform a retrospective, descriptive, histopathological study of peri-implant tissue pathologies associated with titanium dental implants (TDI), and to evaluate the presence of metallic particles in samples from a single diagnostic center.

METHODS

Sixty-eight cases of TDI-associated lesions were retrieved from the Surgical Pathology Laboratory archives, School of Dentistry, University of Buenos Aires (UBA) (1990-2018). The study included re-examining the histopathological features of the biopsy samples, analyzing the inflammatory infiltrate, and examining the samples to detect metallic particles whose chemical composition was determined spectrophotometrically (EDS). Available clinical and radiographic data were also reviewed.

RESULTS

The retrieved cases ranged from lesions of inflammatory origin to neoplastic lesions. Metallic particles were observed in 36 cases (52.9%), all of which showed inflammation. Particle length ranged from 2 to 85µm. EDS analysis of the particles/deposits observed in the tissues showed the presence of aluminum, titanium, iron, and nickel, among other elements.

CONCLUSIONS

A significant number of TDI-associated lesions, including cases not reported to date and diagnosed at a single diagnostic center, are shown here. Cases showing particles exhibited an inflammatory response, irrespective of the histopathological diagnosis. The role of metallic particles in the development of TDI-associated lesion is yet to be established.

Allergies to Titanium Dental Implants: What Do We Really Know about Them? A Scoping Review

Simple Summary

The scientific literature repeatedly insists on the success of titanium implants. Nevertheless, the so-called tribocorrosion process releases titanium ions into the surrounding tissues, which can trigger a cascade of reactions, localized or at a distance, or even systemic reactions. Consequently, guidelines should be drawn up before starting treatment; when a hypersensitivity reaction following titanium dental implant placement occurs, a range of treatment alternatives should be clearly established and made available.

Abstract

The purpose of this scoping review was to describe the current state of knowledge and understanding of allergies to titanium dental implants. A scoping review was conducted following the Prisma Extension for Scoping Reviews checklist. An electronic search was performed in five databases complemented by manual and grey literature searches. Fifty-two relevant papers were included for final review. Titanium particles can be released from the surfaces of dental implants in a process called tribocorrosion, which may contribute to bone loss due to inflammatory reaction. Diverse mechanisms have been described that may trigger allergy to titanium, as well as the clinical signs that manifest as the allergy develops. Allergies to titanium are uncommon but represent a real possibility that should not be overlooked in patients requiring prosthodontic rehabilitation with dental implants. Allergy can trigger a range of symptoms. Patients who have already been diagnosed with allergies to other metals will be more predisposed to suffering an allergy to titanium. Further investigation is needed in order to measure the true scope of these allergies.

Porous Tantalum VS. Titanium Implants: Enhanced Mineralized Matrix Formation after Stem Cells Proliferation and Differentiation

Titanium dental implants are used routinely, with surgical procedure, to replace missing teeth. Even though they lead to satisfactory results, novel developments with implant materials can still improve implant treatment outcomes. The aim of this study was to investigate the efficiency of porous tantalum (Ta) dental implants for osseointegration, in comparison to classical titanium (Ti). Mesenchymal stem cells from the dental pulp (DPSC) were incubated on Ta, smooth titanium (STi), and rough titanium (RTi) to assess their adhesion, proliferation, osteodifferentiation, and mineralized matrix production. Cell proliferation was measured at 4 h, 24 h, 48 h with MTT test. Early osteogenic differentiation was followed after 4, 8, 12 days by alkaline phosphatase (ALP) quantification. Cells organization and matrix microstructure were studied with scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Collagen production and matrix mineralization were evaluated by immunostaining and histological staining. MTT test showed significantly higher proliferation of DPSC on Ta at 24 h and 48 h. However, APL quantification after 8 and 12 days was significantly lower for Ta, revealing a delayed differentiation, where cells were proliferating the more. After 3 weeks, collagen immunostaining showed an efficient production of collagen on all samples. However, Red Alizarin staining clearly revealed a higher calcification on Ta. The overall results tend to demonstrate that DPSC differentiation is delayed on Ta surface, due to a longer proliferation period until cells cover the 3D porous Ta structure. However, after 3 weeks, a more abundant mineralized matrix is produced on and inside Ta implants. Cell populations on porous Ta proliferate greater and faster, leading to the production of more calcium phosphate deposits than cells on roughened and smooth titanium surfaces, revealing a potential enhanced capacity for osseointegration.

KRAS mutations in implant-associated peripheral giant cell granuloma

OBJECTIVES

To investigate the molecular pathogenesis of implant-associated peripheral giant cell granuloma (IA-PGCG).

METHODS

A convenience sample of 15 IA-PGCG cases was selected. Hotspot mutations of KRAS, FGFR1, and TRPV4 genes, previously reported in conventional giant cell lesions of the jaws, were investigated by Sanger sequencing. As these mutations could activate MAPK/ERK pathway, the expression of phospho-ERK1/2 was also evaluated by immunohistochemistry.

RESULTS

KRAS mutations were detected in 8/15 (53.4%) samples. Similar to conventional peripheral giant cell granuloma, the KRAS mutations most frequently occurred in codon 146 (p.A146V, n = 3), followed by codon 12 (p.G12A and p.G12D, n = 1 each) and codon 14 (p.V14L, n = 1). Variants of unknown significance (VUS) were also detected in two cases, affecting codons 37 (p.E37K) and 127 (p.T127I). All samples showed wild-type (WT) sequences for FGFR1 and TRPV4 genes. Consistent with MAPK/ERK pathway activation, all mononuclear cells of the lesion showed strong staining for phospho-ERK1/2 protein in the immunohistochemical analysis.

CONCLUSIONS

KRAS mutations and activation of the MAPK-ERK signaling pathway occur in IA-PGCG. This is the first study to demonstrate cancer-associated gene mutations in a non-neoplastic reactive condition associated with dental implants.

Peripheral giant cell granuloma associated with a dental implant

BACKGROUND

Peripheral giant cell granuloma (PGCG) is an uncommon pathology that affects gingival or alveolar mucosa. Although PGCG can be associated with dental implants, little is known about this lesion and implant osseointegration as well as its etiopathogenesis and the treatments available. This study sought to report a rare case of PGCG associated with dental implant, emphasizing its clinical and histopathological aspects.

CASE PRESENTATION

A 53-year-old man had an exophytic, reddish lesion, around a crown attached to a dental implant located in the left mandible. Radiographically, there was bone loss around the implant. After excisional biopsy, histological examination revealed a submucosal proliferation of multinucleated giant cells rendering the diagnosis of peripheral giant cell granuloma. Patient has been under follow-up for 6 months with no recurrence.

CONCLUSIONS

Peri-implant lesions must be completely removed to prevent recurrence of PGCG and implant failure, even in cases suspected to be reactive. Besides, histological examination must be performed on all peri-implant reactions to achieve the appropriate diagnosis and, consequently, the best treatment and follow up.

Research on implants and osseointegration

Osseointegration was originally defined as a direct structural and functional connection between ordered living bone and the surface of a load-carrying implant. It is now said that an implant is regarded as osseointegrated when there is no progressive relative movement between the implant and the bone with which it is in direct contact. Although the term osseointegration was initially used with reference to titanium metallic implants, the concept is currently applied to all biomaterials that have the ability to osseointegrate. Biomaterials are closely related to the mechanism of osseointegration; these materials are designed to be implanted or incorporated into the living system with the aims to substitute for, or regenerate, tissues and tissue functions. Objective evaluation of the properties of the different biomaterials and of the factors that influence bone repair in general, and at the bone tissue-implant interface, is essential to the clinical success of an implant. The Biomaterials Laboratory of the Oral Pathology Department of the School of Dentistry at the University of Buenos Aires is devoted to the study and research of the properties and biological effects of biomaterials for dental implants and bone substitutes. This paper summarizes the research work resulting from over 25 years' experience in this field. It includes studies conducted at our laboratory on the local and systemic factors affecting the peri-implant bone healing process, using experimental models developed by our research team. The results of our research on corrosion, focusing on dental implants, as well as our experience in the evaluation of failed dental implants and bone biopsies obtained following maxillary sinus floor augmentation with bone substitutes, are also reported. Research on biomaterials and their interaction with the biological system is a continuing challenge in biomedicine, which aims to achieve optimal biocompatibility and thus contribute to patient health.

Peri-implant peripheral giant cell lesions: report of 13 new cases and comparative histological and immunohistochemical analysis with peripheral and central giant cell lesions

BACKGROUND

Few cases or peri-implant peripheral giant cell lesions (PGCL) have been reported in the literature. The aim of this study was to report 13 new cases of peri-implant PGCL and compare the expression of smooth muscle actin, Bcl-2 protein, GLUT-1, CD68, osteoprotegerin, receptor activator of nuclear factor kappa-B, Ki-67 and CD34 in these cases with PGCL and central giant cell lesions (CGCL).

MATERIAL AND METHODS

Clinical data were retrieved from the laboratory records and histological analysis was performed using HE-stained slides. Immunohistochemical reactions for the above mentioned antibodies were performed and digitally scored.

RESULTS

Peri-implant PGCL mostly affected the posterior mandible of adult females. CD68 and Bcl-2 expressions were higher in conventional PGCL and CGCL than in peri-implant PGCL ( p=0.033 for CD68 and p<0.0001 for Bcl-2). Microvessel density was higher in conventional peripheral than in central and peri-implant PGCL ( p=0.002). Proliferative index of the mononuclear cells showed no statistically significant differences comparing the three groups but it was higher in peri-implant PGCL.

CONCLUSIONS

The current study demonstrated that peri-implant PGCL is more common in the posterior mandible of adult females. There were some differences in microvessel density, proliferative activity and expression of CD68 and Bcl-2 among conventional PGCL, peri-implant and CGCL. Further studies are encouraged to better understand these early findings.

Esthetic Management of Peripheral Giant Cell Granuloma Affecting a Dental Implant in the Esthetic Zone

INTRODUCTION

A size increase of the gingiva can be a manifestation of gingival disease. While gingival lesions can affect periodontal tissue, only few reports described the association between peripheral giant-cell granuloma (PGCG) with dental implants and their clinical management. Their clinical relevance is of a great interest since some lesions may lead to extensive bone resorption, esthetic alterations, or even tooth/implant loss. To the author's best knowledge, no specific guidelines for the treatment of PGCG affecting dental implant in the esthetic zone have been reported. The aim of this paper was to report an extensive PGCG associated with a dental implant in the esthetic area and its surgical management.

CASE PRESENTATION

A 39-year-old suffered from concussive trauma on her anterior maxillary dentition leading to an expanded, purplish soft tissue lesion surrounding the implant provisional crown on right central maxillary incisor. After complete lesion excision, the implant neck was carefully and gently debrided. Histological analysis confirmed the diagnosis of PGCG. The patient was then evaluated weekly for the first 3 weeks then monthly. No episodes of recurrence were identified. After 16 weeks of undisturbed healing, a soft tissue augmentation via tunnel technique was elected as the first treatment option to improve esthetics. Final implant restoration was delivered. Follow up at 22 months from biopsy excluded any recurrence of PGCG with stability of peri-implant soft tissues.

CONCLUSION

Excisional biopsy, careful removal of irritating factors, monitoring, and connective tissue grafting can esthetically improve a malpositioned implant and showed no recurrence over a period of 22 months.

General review of titanium toxicity

Background

Titanium is a commonly used inert bio-implant material within the medical and dental fields. Although the use of titanium is thought to be safe with a high success rate, in some cases, there are rare reports of problems caused by titanium. In most of these problematic reports, only individual reports are dominant and comprehensive reporting has not been performed. This comprehensive article has been prepared to review the toxicity of titanium materials within the medical and dental fields.

Methods

We used online searching tools including MEDLINE (PubMed), Embase, Cochrane Library, and Google Scholar by combining keywords such as “titanium implant toxicity,” “titanium implant corrosion,” “titanium implant allergy,” and “yellow nail syndrome.” Recently updated data has been collected and compiled into one of four categories: “the toxicity of titanium,” “the toxicity of titanium alloys,” “the toxicity of titanium implants,” and “diseases related to titanium.”

Results

Recent studies with regard to titanium toxicity have been increasing and have now expanded to the medical field in addition to the fields of environmental research and basic science. Problems that may arise in titanium-based dental implants include the generation of titanium and titanium alloy particles and ions deposited into surrounding tissues due to the corrosion and wear of implants, resulting in bone loss due to inflammatory reactions, which may lead to osseointegration failure of the dental implant. These titanium ions and particles are systemically deposited and can lead to toxic reactions in other tissues such as yellow nail syndrome. Additionally, implant failure and allergic reactions can occur due to hypersensitivity reactions. Zirconia implants can be considered as an alternative; however, limitations still exist due to a lack of long-term clinical data.

Conclusions

Clinicians should pay attention to the use of titanium dental implants and need to be aware of the problems that may arise from the use of titanium implants and should be able to diagnose them, in spite of very rare occurrence. Within the limitation of this study, it was suggested that we should be aware the rare problems of titanium toxicity.

Peripheral giant cell granuloma associated with dental implants: a systematic review

The purpose of the present review was to integrate the available published data on peripheral giant cell granuloma (PGCG) associated with dental implants into a comprehensive analysis of its clinical/radiologic features. An electronic search was undertaken in February/2018 in three databases, looking for publications reporting cases of PGCGs associated with dental implants. Nineteen publications were included, reporting 37 implant-associated PGCG. These lesions are more prevalent in women, in mandible, and in posterior regions of the jaws. Both 'excision alone' and 'excision + curettage' presented high recurrence rates (40% and 31.3%, respectively). The etiology of implant-associated PGCG has not yet been determined. Despite the small number of cases reported, implant-associated PGCG shows a high recurrence rate (1/3) for a benign non-neoplastic lesion and sometimes it requires the removal of the associated implant in order to prevent further recurrences. This recurrence rate is not affected by curettage after excision.

Reactive oral lesions associated with dental implants. A systematic review

Reactive lesion formation around dental implants a complication that has been given much consideration. These lesions can lead to marginal bone loss, and consequently, implant failure. In the present systematic review, all reported reactive lesions associated with dental implants in the literature were assessed. An electronic search was performed using PubMed Central, Scopus, Google Scholar, and Science Direct. The search strategy was limited to human studies (case reports and case series), full-text English language articles, published until May 2017. A total of 19 articles reporting 27 lesions in 25 cases were included. Peripheral giant cell granuloma and pyogenic granuloma were the most reactive lesions found around dental implants. The mean age of the patients was 51.28 ± 14.48 years, with a slight female predilection. Posterior mandibular gingiva was the most common location for these lesions. The recurrence rate of lesions was 33.33%, and the chance of implant removal was 29.62%. Due to the clinical significance of these lesions, early histopathologic examination is recommended to exclude the presence of such pathological lesions.

Multinucleated Giant Cells: Good Guys or Bad Guys?

Multinucleated giant cells (MNGCs) are a special class of giant cell formed by the fusion of monocytes/macrophages abundantly found in human tissues. While historically their role around certain classes of biomaterials have been directly linked to a foreign body reaction leading to material rejection, recent accumulating evidence has put into question their role around certain classes of bone biomaterials. It was once thought that specifically in bone tissues, all giant cells were considered osteoclasts characterized by their ability to resorb and replace bone grafts with newly formed native bone. More recently, however, a special subclass of bone biomaterials has been found bordered by large MNGCs virtually incapable of resorbing bone substitutes even years after their implantation yet surrounded by stable bone. Interestingly, research from the field of cardiovascular disease has further shown how a shift in macrophage polarization from M1 "tissue-inflammatory" macrophages toward M2 "wound-healing" macrophages in atherosclerotic plaque may lead to MNGC formation and ectopic calcification of arteries. Despite the growing observation that MNGC formation occurs around certain bone biomaterials, their role in these tissues remains extremely poorly understood and characterized. In summary, four central aspects of this review are discussed with a focus on (1) the role of MNGCs in bone/tissue biology, and their ability to induce vascularization/new bone formation, their role around, (2) bone substitutes for bone augmentation, (3) dental implants, as well as (4) during peri-implant infection. The authors express the necessity to no longer refer to MNGCs as "good" or "bad" cells, but instead point toward the necessity to more specifically characterize them scientifically and appropriately as M1-MNGC and M2-MNGC accordingly. Future research investigating the factors influencing their polarization as a "center of control" is also likely to act as a key factor in the progression/resolution of various diseases.

Titanium Nanoparticle Size Influences Trace Concentration Levels in Skin Appendages

As a result of biotribocorrosion, the surface of a titanium (Ti) biomedical device can be a potential source of systemic contamination with Ti nanoparticles (NPs). Although NPs can be chemically similar, differences in particle size may lead to different biological responses. The aim of this experimental study was to determine Ti trace levels in skin appendages and plasma and explore the influence of NP size on trace levels using a murine model. Results showed the presence of Ti traces in the nails, hair, and plasma. The concentration of the smallest NPs (5 Nm) was higher than that of 10 Nm NPs in all the studied samples. Irrespective of NP size, Ti levels were always lower in plasma than in skin appendages. Ti levels were higher in nails than in hair. Ti NPs size influenced trace concentration levels in hair/nails, suggesting that 5 Nm Ti particles are more easily eliminated through these skin appendages. Given that the nails showed the highest levels of Ti, and that these skin appendages are not exposed to agents that can leach out Ti, as occurs with hair, we propose the nails as the most suitable and reliable bioindicator for monitoring systemic contamination with Ti.

One-Piece Zirconia Ceramic versus Titanium Implants in the Jaw and Femur of a Sheep Model: A Pilot Study

Reports have documented titanium (Ti) hypersensitivity after dental implant treatment. Alternative materials have been suggested including zirconia (Zr) ceramics, which have shown predictable osseointegration in animal studies and appear free of immune responses. The aim of the research was to investigate the bone-to-implant contact (BIC) of one-piece Zr, compared with one-piece Ti implants, placed in the jaws and femurs of domestic sheep. Ten New Zealand mixed breed sheep were used. A One-piece prototype Ti (control) and one Zr (test) implant were placed in the mandible, and one of each implant (Ti and Zr) was placed into the femoral epicondyle of each animal. The femur implants were submerged and unloaded; the mandibular implants were placed using a one-stage transgingival protocol and were nonsubmerged. After a healing period of 12 weeks, %BIC was measured. The overall survival rate for mandibular and femur implants combined was 87.5%. %BIC was higher for Zr implants versus Ti implants in the femur (85.5%, versus 78.9%) (p = 0.002). Zirconia implants in the mandible showed comparable %BIC to titanium implants (72.2%, versus 60.3%) (p = 0.087). High failure rate of both Zr and Ti one-piece implants in the jaw could be attributed to the one-piece design and surface characteristics of the implant that could have influenced osseointegration. Further clinical trials are recommended to evaluate the performance of zirconia implants under loading conditions.

CO2 Laser Excision of a Pyogenic Granuloma Associated with Dental Implants: A Case Report and Review of the Literature

OBJECTIVE

This article reports the CO2 laser excision of a pyogenic granuloma related to dental implants and reviews the current literature on this pathology in association with dental implants.

BACKGROUND DATA

Five publications describe pyogenic granulomas related to dental implants, and a further one describes the removal of such a lesion with an Er:YAG laser; removal with a CO2 laser is not reported.

PATIENTS AND METHODS

A 67-year-old male patient presented with a hyperplastic gingival lesion around two implants in the left lower jaw. The hyperplastic tissue was removed with a CO2 laser (Lasram; model OPAL 25, 25 W continuous wave, 10.600 nm, gas laser), and a vestibuloplasty was performed. The excised tissue was examined histopathologically. The patient was followed up after 4 weeks, 6 weeks, 6 months, and 1 year, and a panoramic X-ray was also made.

RESULTS

There were no complications during surgery or follow-up. The panoramic X-ray taken 1 year after excision showed neither vertical bone loss nor impaired osseointegration of the implant. Histopathology reported a pyogenic granuloma. After vestibuloplasty, the height of the fixed mucosa was satisfactory.

CONCLUSIONS

The CO2 laser seems to be a safe and appropriate tool for removal of a pyogenic granuloma in close proximity to dental implants. The laser parameters must, however, be chosen carefully and any additional irritants should be excluded to prevent a recurrence.

The effect of platform switching on the levels of metal ion release from different implant-abutment couples

The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy (Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups (n=6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope (SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups (P<0.05). Titanium was the highest element to be released regardless of abutment size or connection (P<0.05). SEM images showed pitting corrosion prominent on the outer borders of the implant and abutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples.

Development of Nasopalatine Duct Cyst in Relation to Dental Implant Placement

Background:

Dental implantation is considered as one of the most widely employed procedures in dental practice. Nasopalatine duct cyst (NPDC) is one of the most common developmental cysts in the oral cavity that develops from the proliferation of embryological epithelial remnants of nasopalatine duct.

Aim:

The aim of this study was to highlight the development of NPDC after the placement of dental implants.

Materials and Methods:

A literature search was carried out in March 2015 using PubMed, EMBASE, and Cochrane library databases, searching for articles relating the development of NPDC after placement of dental implants.

Results:

Our search identified only four case reports of NPDC related to dental implants as reported in the literature published in English.

Conclusion:

Placement of dental implants can induce development of NPDCs, indicating that placement of dental implants requires well-trained specialists with perfect skills in dental implantology. Additionally, critical selection of appropriate cases is of great importance in order to avoid the development of such complications.

The Pathogenesis of Implant-Related Reactive Lesions: A Clinical, Histologic and Polarized Light Microscopy Study

BACKGROUND

Peri-implant soft tissue reactive lesions (I-RLs) may jeopardize implant success and survival. To the best of the authors' knowledge, its pathogenesis is unknown. The objective of this study is to conduct a clinicopathologic and polarized light microscopy (PLM) analysis of 14 new I-RLs and compare them with comparable tooth-associated cases (T-RLs) to better understand I-RL pathogenesis.

METHODS

Fifty-eight new cases of I-RL and T-RL were retrieved from the pathology department archives of Rambam Health Care Campus, Haifa, Israel. Retrospective analysis of histopathologic and clinical features was conducted, documented, and then compared for: 1) I-RL (n = 14), 2) peri-implant pyogenic granuloma (I-PG) (n = 5), 3) peri-implant peripheral giant cell granuloma (I-PGCG) (n = 9), 4) T-RL (n = 44), 5) tooth-associated pyogenic granuloma (T-PG) (n = 21), and 6) tooth-associated peripheral giant cell granuloma (T-PGCG) (n = 23). Presence of foreign bodies was assessed using PLM.

RESULTS

Foreign bodies were found more commonly in I-RLs (n = 13/14; 93%) when compared with T-RLs (n = 18/44; 41%), which was a statistically significant difference (P = 0.01) with an odds ratio of 7.9. Microscopically, I-PGCG was associated with: 1) lower multinucleated giant cell count (P = 0.04); 2) lower density of mesenchymal cells (P = 0.05); and 3) more diffuse, non-lobulated stromal morphology (P = 0.001). Clinically, I-RLs were found in patients who were older, and all cases were located in the posterior region: mandible (n = 12/14; 86%) and maxilla (n = 2/14; 14%).

CONCLUSIONS

In cases of implant failure, implantation of foreign bodies may play a role with subsequent development of I-PG and I-PGCG-like lesions. Clinicians should be aware of this risk so they can implement measures to minimize adverse implant outcomes.

Clinical Management of a Peri-Implant Giant Cell Granuloma

Purpose. Implant therapy plays an important role in contemporary dentistry with high rates of long-term success. However, in recent years, the incidence of peri-implantitis and implant failures has significantly increased. The peripheral giant cell granuloma (PGCG) rarely occurs in peri-implant tissues and it is clinically comparable to the lesions associated with natural teeth. Therefore, the study of possible diseases associated with dental implants plays an important role in order to be able to diagnose and treat these conditions. Materials and Methods. This report described a 60-year-old Caucasian male who presented a reddish-purple pedunculated mass, of about 2 cm in diameter, associated with a dental implant and the adjacent natural tooth. Results. An excisional biopsy was performed and the dental implant was not removed. Histological examination provided the diagnosis of PGCG. After 19-month follow-up, there were no signs of recurrence of peri-implantitis around the implant. Conclusion. The correct diagnosis and appropriate surgical treatment of peri-implant giant cell granuloma are very important for a proper management of the lesion in order to preserve the implant prosthetic rehabilitation and prevent recurrences.

Pyogenic Granuloma/Peripheral Giant-Cell Granuloma Associated with Implants

Introduction. Pyogenic granuloma (PG) and peripheral giant-cell granuloma (PGCG) are two of the most common inflammatory lesions associated with implants; however, there is no established pathway for treatment of these conditions. This paper aims to illustrate the successful treatment of PG and PGCG and also report a systematic review of the literature regarding the various treatments proposed. Methods. To collect relevant information about previous treatments for PG and PGCG involving implants we carried out electronic searches of publications with the key words “granuloma”, “oral”, and “implants” from the last 15 years on the databases Pubmed, National Library of Medicine's Medline, Scielo, Scopus, and Cochrane Library. Results. From the electronic search 16 case reports were found showing excision and curettage as the main successful treatment. As no clinical trials or observational studies were identified the authors agreed to present results from a review perspective. Conclusion. This is the largest analysis of PG and PGCG associated with implants published to date. Our review would suggest that PGCG associated with implants appears to have a more aggressive nature; however the level of evidence is very limited. Further cohort studies with representative sample sizes and standard outcome measures are necessary for better understanding of these conditions.

Pyogenic granuloma in relation to dental implants: Clinical and histopathological findings

Background

The occurrence of pyogenic granuloma in association to dental implants is rare and only five cases have been reported in the literature.

Material and Methods

Patients charts were analyzed to select patients who had been diagnosed for pyogenic granuloma and its association with dental implants had been evaluated. The clinical status of the dental implants and the prosthesis had also been assessed.

Results

Clinical and histopathological diagnosis of pyogenic granuloma had been reached for soft mass growth in association with dental implants in 10 patients. Histological analysis of all samples was performed to obtain a firm diagnosis of finding against pyogenic granuloma lesions. Accumulation of dental plaque due to poor oral hygiene and improper design of the prosthesis had been related to the occurrence of pyogenic granuoloma. This lesion showed no predilection to specific surface type and had no significant association with marginal bone loss.

Conclusions

Pyogenic granuloma should be included in the differential diagnosis of soft mass growth around dental implants.

Key words:Reactive lesion, soft mass, pyogenic granuloma, dental implant, titanium.

A synergistic effect of albumin and H₂O₂ accelerates corrosion of Ti6Al4V

The synergistic effect of albumin and H2O2 on corrosion of titanium alloy Ti6Al4V in physiological saline was investigated with long-term immersion tests and electrochemical methods. It was found that in the presence of both albumin and H2O2, the rate of metal release in immersion tests was far higher than in the presence of either species alone. Electrochemical polarisation curves and potentiostatic tests showed that H2O2 increased both the rates of the anodic and cathodic reactions, whilst albumin significantly decreased the rate of the cathodic reaction and slightly decreased the rate of the anodic reaction. The synergistic effect of albumin and H2O2 during immersion tests was attributed to the effect of adsorption of albumin in lowering the rate of the cathodic reaction and thus lowering the open circuit potential into the active region of titanium where complexation by H2O2 increased the corrosion rate. The corrosion attack was found to be greater in the β-phase of the alloy. The findings suggest that current standard tests in physiological or phosphate-buffered saline may underestimate the rate of corrosion in the peri-implant environment, in which albumin is the predominant protein, and reactive oxygen species such as H2O2 can occur as a result of inflammatory reactions in response to surgery, infection, or implant corrosion products.

STATEMENT OF SIGNIFICANCE

Corrosion of many biomedical implant materials occurs in the body leading to adverse biological responses. Several components of the environment into which a metal implant is placed including proteins and products of cellular physiology, been shown to modify corrosion resistance. Previously all studies on such components including the common protein albumin and the inflammatory product H2O2 have considered the effects of these species in isolation. For the first time we report a synergistic interaction between albumin and H2O2 significantly accelerating corrosion of Ti6Al4V at physiological pH and temperature. This is attributed to an increased rate of the anodic reaction caused by H2O2 complexation of Ti, suppression of cathodic reaction by albumin adsorption shifting OCP to the active region of Ti6Al4V.