ORAL LICHENOID LESIONS AND ALLERGY TO DENTAL MATERIALS

Assessment of dermal sensitization by nickel salts in a novel humanized TLR-4 mouse model

The fundamental goal of this study was to determine the potential utility of a novel humanized Toll-like receptor-4 (hTLR-4) mouse model for future in vivo studies of nickel allergy. First, mice of both sexes and hTLR-4 expression profiles were incorporated into a Local Lymph Node Assay (LLNA) to assess skin sensitization. Next, a set of hTLR-4 hTLR-4-positive mice (female and male groups) was similarly exposed to vehicle control (VC) or 10% NiSO4 on Days 1, 2, and 3. Mice were euthanized on Day 10, lymph node (LN) cellularity was assessed, LN and spleen cells were phenotyped, and serum was collected to quantify circulating cytokine and IgE levels. In the LLNA, hTLR-4-positive mice of both sexes exhibited enhanced responsivity to nickel. NiSO4 (10%) had a stimulation index (SI) of 3.7 (females) and 3.8 (males) in hTLR-4-positive animals, and an SI of 0.5 (females) and 0.8 (males) in hTLR-4 hTLR-4-negative mice. In the 10d study, hTLR-4-positive mice exposed to 10% NiSO4 exhibited increased LN cellularity (6.0× increase in females, 3.2× in males) and significantly higher concentrations of circulating IgE (4.1× increase in females, 3.4× in males). Significant increases in serum interferon (IFN)-γ, interleukin (IL)-4, and IL-5 levels were seen in female mice, while altered concentrations of IL-4 and IL-10 were detected in male mice. The results of this study ultimately demonstrate that murine expression of hTLR-4 confers enhanced susceptibility to dermal sensitization by nickel, and consequently, the hTLR-4 mouse model represents a viable approach for future studies of nickel allergy in vivo.

Guidance on the assessment of biocompatibility of biomaterials: Fundamentals and testing considerations

BACKGROUND

Assessing the biocompatibility of materials is crucial for ensuring the safety and well-being of patients by preventing undesirable, toxic, immune, or allergic reactions, and ensuring that materials remain functional over time without triggering adverse reactions. To ensure a comprehensive assessment, planning tests that carefully consider the intended application and potential exposure scenarios for selecting relevant assays, cell types, and testing parameters is essential. Moreover, characterizing the composition and properties of biomaterials allows for a more accurate understanding of test outcomes and the identification of factors contributing to cytotoxicity. Precise reporting of methodology and results facilitates research reproducibility and understanding of the findings by the scientific community, regulatory agencies, healthcare providers, and the general public.

AIMS

This article aims to provide an overview of the key concepts associated with evaluating the biocompatibility of biomaterials while also offering practical guidance on cellular principles, testing methodologies, and biological assays that can support in the planning, execution, and reporting of biocompatibility testing.

Cancer Stem Cells' Biomarker ALDH1&2 Increased Expression in Erosive Oral Lichen Planus Compared to Oral Leukoplakia

INTRODUCTION

ALDH1&2 has been considered an oral cancer stem cell (CSC) marker. Oral carcinogenesis is a process that usually passes through oral potentially malignant disorders (OPMD). Oral lichen planus (OLP) consists of immune-related chronic disorders that have been included in the OPMDs due to their possible transformation into oral cancer. The aim of this study was to investigate the early presence of ALDH1&2 in OLP compared to early oral leukoplakias (OL), especially mildly and non-dysplastic OL.

MATERIALS AND METHODS

The study type is experimental, and the study design is characterized as semiquantitative research which belongs to the branch of experimental research. The study sample consisted of paraffin-embedded OLP biopsy samples from the archives of the Department of Oral Medicine/Pathology, School of Dentistry, Aristotle University of Thessaloniki, Greece, during the period 2009-2019. The study sample contained 24 cases of OLP (14 erosive and 10 reticular) and 30 cases of OL (16 cases of moderately and severely dysplastic OL and 14 cases of mildly and non-dysplastic OL). The CSC-related biomarker ALDH1&2 was examined using semiquantitative immunohistochemistry (monoclonal antibody sc-166362, Santa Cruz Biotechnology, Dallas, Texas, USA, 1:100). ALDH1&2 expression was evaluated through a scale of 1 to 3 depending on the percentage of positive epithelial cells and was compared to normal epithelium as well as cases of OL (the most prominent OPMD). The statistical analysis was performed with the Pearson chi-square test and the significance level was set at p≤0.05.

RESULTS

The cytoplasmic staining of ALDH1&2 was observed mostly in the epithelial cells of the basal layer of the epithelium of OLP. Overall, this expression was significantly increased compared to normal epithelium. In addition, statistically significantly higher expression of ALDH1&2 was observed in the erosive form of OLP. Interestingly, this OLP positivity was higher compared to mild and non-dysplastic leukoplakias (p<0.001).

CONCLUSIONS

ALDH1&2 is a confirmed CSC marker that was found to be clearly increased in OLP and characteristically in erosive OLP epithelium for the first time. Noteworthy, it was more prominent in erosive OLP rather than in mildly and non-dysplastic OL. Whether this pattern of expression raises the red flag of an early epithelial "CSC" phenotype in OLP or that ALDH1&2 expression indicates a response to the OLP inflammatory process requires further investigation.

The Influence of Fixed Dental Prostheses on the Expression of Inflammatory Markers and Periodontal Status-Narrative Review

A dental prosthesis will only be successful if the restoration lasts for a long period and does not cause any illness. The presence of permanent prosthetic restorations has been linked to an increased risk of periodontal infections, according to a large body of research that has been gathered. When chronic inflammation is brought on by fixed prosthetic constructions, both cellular and noncellular immunity are activated as adaptive immune mechanisms. It has previously been stated that both clinically adequate and inadequate restorations might cause gingival inflammation. Areas surrounding the abutment teeth presented periodontal pockets, attachment loss, congestion, bleeding on probing, and gingival hyperplasia after fixed restorations were removed. The depth of pockets, bleeding on probing, and bone loss are all closely correlated with disease's severity and IL-1β concentration in gingival crevicular fluid; IL-1β shows higher values in disease sites than in healthy ones. hs-CRP and TNF-α blood levels showed a considerable reduction one day after fixed restorations were applied, in comparison with the pre-treatment values. Collaboration between prosthodontists and periodontists is essential for a good treatment outcome since it will increase the restoration's lifespan, enhance periodontal health, and improve the quality of life for dental patients.

Comparison of Short-Term Restorative Effects and Periodontal Health Status of Restorations Made of Different Materials in Full-Crown Restoration of Mandibular Premolar Tooth Defects

Purpose

To compare the short-term restorative effect and periodontal health status of restorations with different materials in full-crown restoration of mandibular premolar tooth defects.

Methods

A total of 105 cases (123 affected teeth) of mandibular premolar tooth defects who visited the Department of Stomatology between January 2019 and January 2020 were selected, of which 58 cases (68 affected teeth) restored with cobalt-chromium alloy porcelain crowns were included in the metal-ceramic crown (MCC) group and 47 cases (55 affected teeth) repaired by zirconium dioxide all-ceramic crowns were assigned to the zirconia crown (ZC) group. The restorative effect, inflammatory factors (high-sensitivity C-reactive protein (hs-CRP) and tumor necrosis factor-α (TNF-α)) and periodontal health indicators (human cartilage glycoprotein-39 (YKL-40), resistin, aspartate aminotransferase (AST), and alkaline phosphatase (ALP)) after treatment, and the occurrence of adverse reactions were compared between the two groups.

Results

The ZC group outperformed the MCC group in terms of margin fitness, restoration fracture, gingival condition, and color matching. After restoration, hs-CRP and TNF-α were statistically decreased in both groups, while YKL-40, resistin, AST, and ALP were significantly increased; and compared with the MCC group, hs-CRP, TNF-α, YKL-40, resistin, AST, and ALP were lower in the ZC group. The ZC group also scored statistically higher in retention effect, aesthetic effect, masticatory function, voice function, and comfort. Moreover, the ZC group had a higher total effective rate and a lower incidence of adverse reactions than the MCC group, with statistical significance.

Conclusions

Zirconia dioxide all-ceramic crowns contribute to a better short-term restorative effect in the full-crown restoration of mandibular premolar tooth defects, with little impact on periodontal health and high patient satisfaction, which deserves popularization and application.

Oral Microbiome Research on Oral Lichen Planus: Current Findings and Perspectives

Simple Summary

Oral lichen planus is a disease of the oral mucosa, which frequently affects women aged 40 years or older. Though the T cell-mediated immune response is involved in the development of oral lichen planus, attempts to identify a microorganism that causes the disease have been unsuccessful. Recent studies on the development of oral lichen planus are focusing on the role of the oral microbiome, which includes oral microbiota and their products, and the host environment. The role of the human microbiome in various diseases has been identified and regulating the microbiome is becoming important in personalized medicine. In this review, we summarized current findings on the role of the oral microbiome in the development of oral lichen planus. The homeostasis of the oral microbiome is disrupted in patients, and functional analysis of oral microbiota and oral mucosa implies that pathways involved in defense against bacterial infection and in the inflammatory response are activated in the oral lichen planus-associated oral microbiome. Though the lack of studies to date makes it difficult to conclude, further studies on the oral microbiome associated with the disease will enable a holistic understanding of the role of the oral microbiome in the development of oral lichen planus and developing a personalized therapy for the disease.

Abstract

Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa with an unknown etiology. The role of oral microbes in the development of OLP has gained researchers’ interest. In this review, we summarized the findings of studies focused on the relationship between OLP and oral microbiome, which includes the composition of oral microbiota, molecules produced by oral microbiota or the host, and the oral environment of the host. According to the studies, the oral microbial community in OLP patients undergoes dysbiosis, and the microbial dysbiosis in OLP patients is more prominent in the buccal mucosa than in the saliva. However, no same microorganisms have been suggested to be associated with OLP in multiple investigations, implying that the functional aspects of the oral microbiota are more important in OLP development than the composition of the oral microbiota. According to studies on host factors that make up the oral environment, signal pathways involved in cellular processes, such as keratinization, inflammation, and T cell responses are triggered in OLP. Studies on the functional aspects of the oral microbiota, as well as interactions between the host and the oral microbiota, are still lacking, and more research is required.

Is Allergy to Titanium Bone Fixation Plates a Problem?

Open reduction and internal fixation (ORIF) with titanium fixation plates is the gold standard for maxillofacial fracture treatment. Titanium is considered a fully compatible material. However, reports of allergic reactions to titanium implants do occur. The aim of this work is to answer the question whether titanium devices used in the treatment of fractures in the craniofacial region can cause allergic reactions. The study comprised 50 subjects treated surgically for maxillofacial injuries with the use of titanium composite devices. Allergic tests were performed by the patch method. The control group consisted of 20 healthy people who did not have any titanium elements. There were no skin changes to titanium and its compounds in both the test and control groups. Only one patient had a positive skin test which showed an allergic reaction to silver nitrate. Titanium fixing elements, as well as titanium dental implants, according to our research, do not show allergic skin reactions.

Recent update on potential cytotoxicity, biocompatibility and preventive measures of biomaterials used in dentistry

Dental treatment is provided for a wide variety of oral health problems like dental caries, periodontal diseases, periapical infections, replacement of missing teeth and orthodontic problems. Various biomaterials, like composite resins, amalgam, glass ionomer cement, acrylic resins, metal alloys, impression materials, bone grafts, membranes, local anaesthetics, etc., are used for dental applications. The physical and chemical characteristics of these materials influence the outcome of dental treatment. It also impacts on the biological, allergic and toxic potential of biomaterials. With innovations in science and their positive results, there is also a need for awareness about the biological risks of these biomaterials. The aim of dental treatment is to have effective, yet safe, and long-lasting results for the benefit of patients. For this, it is important to have a thorough understanding of biomaterials and their effects on local and systemic health. Materials used in dentistry undergo a series of analyses before their oral applications. To the best of our knowledge, this is the first and original review that discusses the reasons for and studies on the toxicity of commonly used biomaterials for applications in dentistry. It will help clinicians to formulate a methodical approach for the selection of dental biomaterials, thus providing an awareness for forecasting their risk of toxic reactions.

Hawley retainer and lichenoid reaction: a rare case report

BACKGROUND

Oral lichenoid reaction (OLR) is a type IV cell-mediated immune response in the oral cavity. There is an established relationship between various dental materials and OLR, but few cases reports reported the occurrence of a lichenoid reaction in association with the use of a Hawley retainer.

CASE PRESENTATION

A female patient (twenty years of age) has been complaining of a reddish painful area on the tongue, which started one year ago and has been increasing in size over time. The patient completed orthodontic treatment two years ago and has been using a Hawley retainer for orthodontic retention since then. After performing histological analysis and patch test, the lesion was diagnosed as a lichenoid reaction to the Hawley retainer. Topical corticosteroids were prescribed, and the patient was asked to stop using the retainer and followed for six months.

CONCLUSIONS

It is difficult to diagnose lichenoid lesions and even more challenging to differentiate between OLP and OLR, therefore it is essential to do a full intraoral and extraoral examination. OLL can occur in association with Hawley retainer, which we believe could be because it is made of an acrylic based material. Generally, OLL resolves after removal of the cause.

A review on potential toxicity of dental material and screening their biocompatibility

OBJECTIVES

A wide range of compounds are utilized in dentistry such as dental composites, resins, and implants. The successful clinical use of dental materials relies on theirm physiochemical properties as well as biological and toxicological reliability. Different local and systemic toxicities of dental materials have been reported. Placement of these materials in oral cavity for a long time period might yield unwanted reactions. An extensive variety of materials is used in dentistry including filling materials, restorative materials, intracanal medicines, prosthetic materials, different types of implants, liners, and irrigants. The increasing rate in development of the novel materials with applications in the dental field has led to an increased consciousness of the biological risks and tempting restrictions of these materials. The biocompatibility of a biomaterial used for the replacement or filling of biological tissue such as teeth always had a high concern within the health care disciplines for patients.

MATERIALS AND METHODS

Any material used in humans should be tested before clinical application. There are many tests evaluating biocompatibility of these materials at the point of in vitro, in vivo, and clinical investigations.

RESULTS

The current review discusses the potential toxicity of dental material and screening of their biocompatibility.

CLINICAL RELEVANCE

It is essential to use healthy and safe materials medical approaches. In dentistry, application of different materials in long-term oral usage demands low or nontoxic agents gains importance for both patients and the staff. Furthermore, screening tests should evaluate any potential toxicity before clinical application.

Characterization of T cell receptors in a novel murine model of nickel-induced intraoral metal contact allergy

Nickel is a component of several alloy types that are widely used in our environment, including several dental alloy types that cause intraoral metal contact allergy. However, metal-specific immune responses in the oral mucosa have not been elucidated because a suitable animal model has not been established. In this study, we established a novel murine model of nickel-induced intraoral metal contact allergy and aimed to elucidate the immune response in terms of T-cell receptor repertoire and cytokine profiles in inflamed oral mucosa. The intraoral metal contact allergy model was induced by two sensitizations of nickel plus lipopolysaccharide solution into the postauricular skin followed by a single nickel challenge of the buccal mucosa. Cytokine expression profiles and T-cell phenotypes were determined by quantitative polymerase chain reaction. T cells accumulated in the cervical lymph nodes and inflamed oral mucosa were characterized by analyzing their T-cell receptor α- and β-chain repertoires, and the nucleotide sequences of complementary determining region 3. Significant swelling and pathological features were histologically evident at 1 day after challenge in mice with nickel allergy. At 1 day after the challenge, CD8-positive T cells producing high levels of T helper 1 type cytokines had accumulated in the allergic oral mucosa. At 7 days after the challenge, excessive nickel allergy in the oral mucosa was suppressed by regulatory T cells. Characterization of the T-cell receptor repertoire in nickel allergic mice revealed the presence of natural killer T cells and T cells bearing Trav6-6-Traj57 at 1 day after the challenge. Our murine model of nickel-induced intraoral metal contact allergy showed that natural killer T cells and T cells bearing Trav6-6-Traj57 might be involved in the immune responses of nickel-induced intraoral metal contact allergy.

Five hundred patients reporting on adverse effects from dental materials: Frequencies, complaints, symptoms, allergies

OBJECTIVE

Information on patients with real or claimed adverse reactions towards dental materials in large patient cohorts is rare. Therefore, the aim of the present study was to investigate patients reporting on complaints and symptoms to dental materials over a 16-year period.

METHODS

Five hundred patients were characterized by one single dental team regarding age and sex distribution, subjective complaints and objective intraoral symptoms, and allergy status relevant to dental materials.

RESULTS

Elder patients and females predominated. Subjective complaints were reported by 490 patients, ranging from 1 to 12 complaints per patient. Most often, burning mouth (44%), tooth-/jawache (22%) and dry mouth (20%) were reported. In 54% no objective intraoral symptom was diagnosed. The main objective intraoral symptoms were tongue anomalies (lingua plicata or geographica; 14%), gingivitis adjacent to restorations (12%), redness of the palate or the edentulous ridge (7%), oral lichen planus (6%), grayish discolorations, lichenoid contact lesions, and leukoplakia (<5%). Patch testing of 416 (83%) patients revealed that allergy was diagnosed as contributing to the complaints or symptoms in 70 (14%) patients with metals being the most frequent allergens. Gingivitis adjacent to restorations (3.2%), redness of the palate or edentulous ridge (1.4%) and whitish lichen-like lesions (1.8%) were associated to allergy from dental materials.

SIGNIFICANCE

The high number of subjective complaints per patient and their wide variety suggests that most patients seriously suffered. Furthermore, the fact that only 46% of the patients had objective intraoral symptoms demands for an interdisciplinary collaboration to elucidate other than dental causes.

Metal allergy patient treated by titanium implant denture: A case report with at least 4-year follow-up

Patch testing with metal reagents was positive on female patient with history of metal hypersensitivity after dental treatment. All of the dental restorations with metal components were removed, and subsequent oral rehabilitation utilizing dental implants and metal-free prostheses was carried out. The treatments alleviate the presenting signs and symptoms.

Effect of Fixed Metallic Oral Appliances on Oral Health

There is a substantial proportion of the population using fixed metallic oral appliances, such as crowns and bridges, which are composed of various dental alloys. These restorations may be associated with a number of effects on oral health with variable degrees of severity, to review potential effects of using fixed metallic oral appliances, fabricated from various alloys. The MEDLINE/PubMed database was searched using certain combinations of keywords related to the topic. The search revealed that burning mouth syndrome, oral pigmentation, hypersensitivity and lichenoid reactions, and genotoxic and cytotoxic effects are the major potential oral health changes associated with fixed prosthodontic appliances. Certain oral disorders are associated with the use of fixed metallic oral appliances. Patch test is the most reliable method that can be applied for identifying metal allergy, and the simultaneous use of different alloys in the mouth is discouraged.

Proposed ICDRG Classification of the Clinical Presentation of Contact Allergy

The International Contact Dermatitis Research Group proposes a classification for the clinical presentation of contact allergy. The classification is based primarily on the mode of clinical presentation. The categories are direct exposure/contact dermatitis, mimicking or exacerbation of preexisting eczema, multifactorial dermatitis including allergic contact dermatitis, by proxy, mimicking angioedema, airborne contact dermatitis, photo-induced contact dermatitis, systemic contact dermatitis, noneczematous contact dermatitis, contact urticaria, protein contact dermatitis, respiratory/mucosal symptoms, oral contact dermatitis, erythroderma/exfoliative dermatitis, minor forms of presentation, and extracutaneous manifestations.

Oral Lichenoid and Lichen Planus-like Lesions

Many red and white lesions of the mouth are clinically indistinguishable from those of oral lichen planus (OLP). These lesions, often referred to as oral lichenoid lesions (OLL), can occur as a result of contact sensitivity (lichenoid contact reactions), drug reactions or as part of chronic graft versus host disease (GVHD). Oral lesions in discoid lupus erythematosus (DLE) and systemic lupus erythematosus (SLE) can also have a similar clinical appearance to OLP. Distinguishing oral lichen planus from oral lichenoid lesions, lupus lesions, or other red and white lesions of the mouth can be difficult (even impossible) but it is important, for optimal management of each condition. All patients with red and white pathological lesions should be referred to an oral medicine or a local oral or maxillofacial surgery department, where a biopsy and other investigations can help to establish a diagnosis, and appropriate treatment and monitoring can be commenced. Dentists and other members of the dental team, such as hygienists and dental therapists, should also equip themselves with the knowledge to be able to explain different pathologies of the mouth to their patients and discuss risk factors.

Lichenoid reaction associated with silver amalgam restoration in a Bombay blood group patient: A case report

The pathogenic relationship between the oral lichenoid reaction (OLR) and dental restorative materials has been confirmed many times. An OLR affecting oral mucosa in direct contact with an amalgam restoration represents a delayed, type IV, cell mediated immune response to mercury or one of the other constituents of the dental amalgam. Bombay blood group patients are more prone to this. A case of bilateral OLR is presented, which is present in relation to amalgam restoration. The lesion healed up after the replacement of restorations with an intermediate restorative material. The clinician should be aware of all the possible pathological etiologies of white lesions. If there is any doubt about the nature or management of a usual oral lesion, a referral to an appropriate specialist is mandatory.

Potential hazards due to food additives in oral hygiene products

Food additives used to preserve flavor or to enhance the taste and appearance of foods are also available in oral hygiene products. The aim of this review is to provide information concerning food additives in oral hygiene products and their adverse effects. A great many of food additives in oral hygiene products are potential allergens and they may lead to allergic reactions such as urticaria, contact dermatitis, rhinitis, and angioedema. Dental practitioners, as well as health care providers, must be aware of the possibility of allergic reactions due to food additives in oral hygiene products. Proper dosage levels, delivery vehicles, frequency, potential benefits, and adverse effects of oral health products should be explained completely to the patients. There is a necessity to raise the awareness among dental professionals on this subject and to develop a data gathering system for possible adverse reactions.

Oral lichen planus to oral lichenoid lesions: Evolution or revolution

The diagnosis between different diseases may be impaired by clinical and histopathologic similarities, as observed in the oral lichen planus (OLP) and oral lichenoid lesion (OLL). Inspite of similar clinicopathological features; etiology, diagnosis and prognosis differ which mandates separation of OLL from OLP. Hence, it is essential for the oral physician and oral pathologist to be familiarized with the individual variations among clinicopathological features of OLP and OLL as well as to obtain a thorough history and perform a complete mucocutaneous examination in addition to specific diagnostic testing. The difficulties faced to establish the diagnosis between these two pathologies are widely investigated in the literature with a lack of definite conclusion. This review is an attempt to throw some light on these clinicopathologic entities with the aim to resolve the diagnostic dilemma.

Allergic Reactions to Dental Materials-A Systematic Review

INTRODUCTION

Utility of various dental materials ranging from diagnosis to rehabilitation for the management of oral diseases are not devoid of posing a potential risk of inducing allergic reactions to the patient, technician and dentist. This review aims to develop a systematic approach for the selection and monitoring of dental materials available in the market thereby giving an insight to predict their risk of inducing allergic reactions.

MATERIALS AND METHODS

Our data included 71 relevant articles which included 60 case reports, 8 prospective studies and 3 retrospective studies. The source of these articles was Pub Med search done with the following terms: allergies to impression materials, sodium hypochlorite, Ledermix paste, zinc oxide eugenol, formaldehyde, Latex gloves, Methyl methacrylate, fissure sealant, composites, mercury, Nickel-chromium, Titanium, polishing paste and local anaesthesia. All the relevant articles and their references were analysed. The clinical manifestations of allergy to different dental materials based on different case reports were reviewed.

RESULTS

After reviewing the literature, we found that the dental material reported to cause most adverse reactions in patients is amalgam and the incidence of oral lichenoid reactions adjacent to amalgam restorations occur more often than other dental materials.

CONCLUSION

The most common allergic reactions in dental staff are allergies to latex, acrylates and formaldehyde. While polymethylmethacrylates and latex trigger delayed hypersensitivity reactions, sodium metabisulphite and nickel cause immediate reactions. Over the last few years, due to the rise in number of patients with allergies from different materials, the practicing dentists should have knowledge about documented allergies to known materials and thus avoid such allergic manifestations in the dental clinic.

Patch Testing with Dental Screening Series in Oral Disease

Background

The oral mucosa is constantly exposed to several irritants and allergens including dental materials, but the role of contact allergy in oral disease is obscure.

Objective

To analyze positive patch test results in patients with oral diseases and evaluate the clinical relevance of oral diseases with contact allergy to dental materials.

Methods

We retrospectively analyzed patch test results with dental screening series in 44 patients with oral disease from 2004~2011.

Results

Oral diseases included oral lichen planus (54.5%), cheilitis (27.3%), burning mouth syndrome (9.1%), and others (9.1%). Thirty-one of 44 patients (70.5%) had positive reactions to one or more allergens. The most commonly detected allergens were gold sodium thiosulfate (25.0%) and nickel sulfate (25.0%), followed by potassium dichromate (22.7%), cobalt (15.9%), palladium (6.8%), mercury (4.5%), copper (4.5%), and methylhydroquinone (4.5%). Six of 24 patients with oral lichen planus had a symptom in areas adjacent to dental materials and positive patch test reactions to allergens contained in the suspected dental materials.

Conclusion

Patch tests with dental screening series are worth considering for oral diseases, especially for oral lichen planus.

The role of patch testing in the management of oral lichenoid reactions

BACKGROUND AND OBJECTIVES

The distinction of oral lichenoid reactions from oral lichen planus may be difficult in a clinical setting. Our aims were to ascertain the utility of patch testing to confirm the association of oral lichenoid reactions with dental restorations and to identify the benefits of replacement of restorations, primarily made of amalgam.

METHODS

Patients seen in an oral medicine unit over a 10-year period diagnosed with oral lichenoid reactions, with oral lichen planus resistant to treatment or with atypical lichenoid features were included in this study. All had been subjected to skin patch testing. Histopathology reports blinded to patch test results were scrutinized. Patch-test-positive subjects were advised to have their restorations replaced. All were followed up to determine disease resolution for at least 3 months thereafter.

RESULTS

Among 115 patients, 67.8% patients reacted positive to a dental material and nearly a quarter to mercury or amalgam. No correlation was found between pathology and skin patch testing results (P = 0.44). A total of 87 patients were followed up in clinic, and among 26 patch-test-positive patients who had their amalgam fillings replaced, moderate to complete resolution was noted in 81%.

CONCLUSIONS

Skin patch testing is a valuable tool to confirm clinically suspected oral lichenoid reactions. Pathology diagnoses of oral lichenoid reactions did not correlate with patch test results. Prospective studies are needed to ascertain that a clinically suspected oral lichenoid reaction with a positive patch test result may resolve after the replacement of amalgam fillings.

Evaluation of the Effects of Dental Implants on Oral Lesions

OBJECTIVE

To determine whether dental implants impress oral lesions, and to evaluate the nature of their effect on the lesions.

MATERIALS AND METHODS

A comprehensive search was done via Google and PubMed for articles (including case reports and literature reviews) containing the keywords 'oral squamous cell carcinoma' (OSCC), 'oral lichen planus' (OLP), 'lichenoid contact reaction' (LCR), 'osseointegrated implants', and 'dental implants' , in the last 10 years (2002-2012).

RESULTS

The study included 24 articles involving patients with dental implants, and some oral lesions (e.g. oral lichen planus and oral squamous cell carcinoma) or with a history of lesions. In these publications, there is evidence suggesting the possibility of emergence, exacerbation, recurrence, or even malignant transformation of the oral lesions after implant placement in some cases.

CONCLUSION

Based on our review of the literature, implant treatment does not seem to be completely safe under any circumstances, but may have some complications in subjects with certain diseases (e.g. oral lesions, autoimmune diseases, malignancies, allergic reactions, etc.). Therefore prior to treatment, patients should be fully informed of the risks.

CLINICAL SIGNIFICANCE

Implant treatment is best done with caution in patients with cancer or mucocutaneous disorders.

A clinical report of an oral lichen planus associated to epidermoid carcinoma in contact with metallic restorations

The aim of this study was to relate the clinical case of a patient with oral lichen planus (OLP) and a history of epidermoid carcinoma associated with metallic restorations. The etiology of OLP is a mucocutaneous disease, which is poorly understood. Studies point to the potential of malignant transformation of OLP and its association with metallic restorations. The metallic restorations were replaced by crowns with a ceramic covering associated and osseointegrated implants in the edentulous areas. About 1 year later, it was observed a bilateral regression of the tongue lesions. The replacement of metallic restorations can contribute to improvement of OLP.

Systemic contact dermatitis and allergy to biomedical devices

Systemic contact dermatitis (SCD) refers to a skin condition where an individual who is cutaneously sensitized to an allergen will subsequently react to that same allergen or a cross-reacting allergen via the systemic route. It occurs to allergens including metals, medications, and foods. There has been recent interest in metal allergy as it relates to the implantation of devices such as orthopedic, dental, cardiac, and gynecologic implants. This review will briefly address all causes of systemic contact dermatitis with a special and expanded focus on metal implant allergy. We present literature on SCD to various metal biomedical devices, patch testing for diagnosis of metal allergy pre and post implantation and treatment.

Indium chloride-induced micronuclei via reactive oxygen species in Chinese hamster lung fibroblast V79 cells

We study the cytotoxicity of indium chloride (InCl₃) in Chinese hamster lung fibroblasts, the V79 cells, using MTT assay. The results showed that InCl₃ did not induce significant cytotoxicity at various concentrations tested. In addition, the frequency of micronuclei (MN) was assayed to evaluate the genotoxic effects of InCl₃ in V79 cells. InCl₃ at concentrations ranged 0.1-1 μM significantly increased MN frequency in a concentration-dependent manner. Both catalase and superoxide dismutase at concentrations of 75 and 150 μg/mL significantly inhibited InCl₃-induced MN. Similarly, Germanium oxide (GeO₂) and dimercaprol expressed antigenotoxic effects. From these findings, it is concluded that InCl₃ is a potent genotoxic chemical, which may be mediated partly by inducing oxidative stress. The significance of this study shows that the workers in the semiconductor factories should be cautious in exposing to the hazardous genotoxic InCl₃.

Oral lichenoid contact lesions to mercury and dental amalgam--a review

Human oral mucosa is subjected to many noxious stimuli. One of these substances, in those who have restorations, is dental amalgam which contains mercury. This paper focuses on the local toxic effects of amalgam and mercury from dental restorations. Components of amalgam may, in rare instances, cause local side effects or allergic reactions referred to as oral lichenoid lesions (OLLs). OLLs to amalgams are recognised as hypersensitivity reactions to low-level mercury exposure. The use of patch testing to identify those susceptible from OLL is explored, and recommendations for removing amalgam fillings, when indicated are outlined. We conclude that evidence does not show that exposure to mercury from amalgam restorations poses a serious health risk in humans, except for an exceedingly small number of hypersensitivity reactions that are discussed.

Urban legends series: lichen planus

Oral Diseases (2012) Lichen planus (LP) is a common disorder affecting the oral cavity (OLP) and skin. Despite intensive research, LP/OLP etiology and treatment remain controversial. We investigated four controversial topics: (i) Is hepatitis C virus (HCV) infection associated with LP and involved in its pathogenesis? (ii) Should all patients with LP be screened for HCV? (iii) Should patients with OLP have all their amalgam restorations removed? (iv) Are there any new treatments for OLP? Results from extensive literature searches suggested that: (i) Robust evidence from three meta-analyses indicate that HCV is associated with LP and might be involved in OLP pathogenesis (ii) It would be prudent to screen patients with LP/OLP at significant risk with an ELISA for HCV antibodies using country-specific screening strategies (iii) There is no evidence that either OLP or oral lichenoid lesions patients would routinely benefit from having all their amalgam restorations replaced. Weak evidence from potentially very biased, small, non-randomized, unblinded studies suggests that a small fraction of patients may benefit from targeted amalgam replacement. (iv) There is weak evidence that, among new OLP treatments, topical pimecrolimus, aloe vera, and oral curcuminoids may be useful. The development of specific formulations for oral delivery of topical medications is a promising field.

Determination of susceptibility to sensitization to dental materials in atopic and non-atopic patients

Introduction: Some studies report that atopic patients have a greater frequency of delayed-type sensitization than non-atopic patients. Objective: To determine the influence of the atopic condition on delayed sensitization to dental materials. Design: cross-sectional study. Methods: Forty (40) atopic subjects and forty (40) non-atopic subjects, of both sexes, between 20 and 65 years of age were included. The determination of delayed sensitization to dental materials was performed using patch test. An oral exam was also carried out to check for lesions of the oral mucosa. Results: 61.25% of the patients were positive for delayed-type sensitization to one or more allergens, being palladium chloride (21.25%), ammoniated mercury (20%), benzoyl peroxide (12.5%) and amalgam (10%) the most frequent. The frequency of sensitization was 67.5% in the group of atopic patients, compared to 55% in the non atopic group (p>0.05). The materials with the greatest difference of sensitization in atopic compared to non-atopic patients were ammoniated mercury, benzoyl peroxide, amalgam and Bisphenol A Dimethacrylate (BIS-GMA). Conclusion: The atopic condition is not related to a higher frequency of delayed sensitization to a battery of dental materials.

Key words: Patch test, delayed-type sensitization, allergy contact, atopia, dental materials.