Oral diseases associated with fixed prosthodontic restorations

Characterization of Metal-Specific T-Cells in Inflamed Oral Mucosa in a Novel Murine Model of Chromium-Induced Allergic Contact Dermatitis

The element chromium (Cr) is a component of several types of alloys found in the environment, or utilized in dentistry, that may cause intraoral metal contact allergy. However, the pathological mechanism of intraoral Cr allergy remains unclear because there is no established animal model of Cr allergy in the oral mucosa. In this study, we established a novel murine model of Cr-induced intraoral metal contact allergy and elucidated the immune response in terms of cytokine profiles and T-cell receptor repertoire. Two sensitizations with Cr plus lipopolysaccharide solution into the postauricular skin were followed by a single Cr challenge of the oral mucosa to generate the intraoral metal contact allergy model. Histological examination revealed that CD3+ T-cells had infiltrated the allergic oral mucosa one day after exposure to the allergen. The increase in T-cell markers and cytokines in allergic oral mucosa was also confirmed via quantitative PCR analysis. We detected Cr-specific T-cells bearing TRAV12D-1-TRAJ22 and natural killer (NK) T-cells in the oral mucosa and lymph nodes. Our model demonstrated that Cr-specific T-cells and potent NKT-cell activation may be involved in the immune responses of Cr-induced intraoral metal contact allergy.

Toxicological Risks of the Cobalt-Chromium Alloys in Dentistry: A Systematic Review

Background: The toxicological risk of Co-Cr dental alloys is actually a sensitive subject with the European regulatory changes, namely regulation (EU) 2017/745 and annex VI to the CLP regulation (EC) 1972/2008. Objectives: The objective of this review is to conduct a rigorous analysis of the cytocompatibility of cobalt-chromium (Co-Cr) dental alloys. Considering various parameters such as cytotoxicity, type IV hypersensitivity reaction, sensitization, and irritation, we investigated evidence of toxicity of Co-Cr in human dental applications. Data sources: Specific search strategies were performed in three electronic databases, namely Medline, Embase, and Web of Science, using a main restriction in the search regarding the publication date (1995-2022). Study selection: Out of a total of 836 articles, only 21 studies were selected and analyzed according to PRISMA methodology. Results: Among them, 10 in vitro studies using human samples and 11 in vivo studies on human patients were distinguished. Most of the in vitro studies confirmed that Co-Cr alloys have a good cytocompatibility compared to Ni alloys. Regarding the in vivo studies, it appeared that Co-Cr could rarely cause sensitization, irritation, and allergic reactions. Reactions were mainly observed for people allergic to Co or Cr. Nevertheless, titanium-based materials showed better results. Conclusions: This study proposes a new state of the art on Co-Cr dental alloys and will thus be very useful for carrying out additional studies. Relevance: This review will help practitioners in their daily clinical choice.

Experimental Study Regarding the Behavior at Different pH of Two Types of Co-Cr Alloys Used for Prosthetic Restorations

Cobalt-chromium (Co-Cr) alloys are widely utilized in dentistry. The salivary pH is a significant factor, which affects the characteristics and the behavior of dental alloys through corrosion. This study aimed to evaluate the corrosion behavior in artificial saliva with different pH values (3, 5.7, and 7.6) of two commercial Co-Cr dental alloys manufactured by casting and by milling. Corrosion resistance was determined by the polarization resistance technique, and the tests were carried out at 37 ± 1 °C, in Carter Brugirard artificial saliva. After the electrochemical parameters, it can be stated that the cast Co-Cr alloy has the lowest corrosion current density, the highest polarization resistance, and the lowest speed of corrosion in artificial saliva with pH = 7.6. In the case of milled Co-Cr alloy, the same behavior was observed, but in artificial saliva with pH = 5.7, it recorded the most electropositive values of open circuit potential and corrosion potential. Although both cast and milled Co-Cr alloys presented a poorer corrosion resistance in artificial saliva with a more acidic pH value, the milled Co-Cr alloy had better corrosion behavior, making this alloy a better option for the prosthetic treatment of patients suffering from GERD.

[Mucoperiodontal lesions: improvement of prosthodontic treatment considering initial indicators of patients' oral health]

OBJECTIVE

To assess the need for prosthodontic treatment and to substantiate the features and perspectives for optimizing prosthodontic treatment in patients with mucoperiodontal manifestations of lichen planus (LP).

MATERIAL AND METHODS

For assessment of the need and identification of problematic aspects of prosthetic treatment 74 patients (48.3% of the primary sample of all patients with oral LP) with oral LP-associated mucoperiodontal lesions (MPL) participated in a multicenter open cohort prospective controlled clinical trial with elements of retrospective analysis. The prospective part of the study summarizes the results of prosthodontic treatment of 41 patients (8 men and 33 women aged 45-70 years) carried out using improved therapeutic and diagnostic algorithms applied to the specifics of the MPL forms and stages.

RESULTS

The use of standard protocols of prosthodontic treatment without taking into account the status of oral mucosa in patients with oral LP was associated with the development of nonspecific (prosthetic stomatitis - 25.8%; contact-allergic stomatitis - 22.6%; focal hyperplasia - 16.1%; decubital ulcers - 12.9%, etc.) and oral LP-associated specific reactions (Kebner's symptom - 35.5%; transformation of the typical form into complicated ones - 22.6%; desquamative gingivitis and gingival lichenization - 19.4% each; gum recession - 16.5%) with the involvement of skin and mucous membranes of other localizations (6.5%) and the appearance of symptoms of carcinophobia/dentophobia (25.8%). Prosthetic treatment according to improved protocols for the management of patients with oral LP indicated a decrease in the frequency of nonspecific oral mucosal reactions (by 70.7%, p<0.001), single (4.8%) specific reactions, improvement of masticatory efficiency by 32.8-55.3% (p<0.01), harmonization of speech function, maintenance of a high level of hygiene of prostheses, a significant reduction in the time of adaptation to removable dentures and increased satisfaction with the results of treatment on the GRS scale (1.06±0.3 points after treatment; 3.8±0.5 points before treatment; p<0.001).

CONCLUSION

The best dynamics of clinical and sociological indicators was noted in persons with prosthetic replacement structures based on implants.

Oral care of a patient with a SAPHO syndrome and a nickel allergy

SAPHO is an acronym for Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis. The syndrome is difficult to diagnose because it may present many different manifestations in adults and children. Its origin is still unknown, although some infectious, genetic and immune hypotheses have been put forward. We report the case of a 49-year-old woman with SAPHO syndrome, who developed a serious cutaneous allergy following the insertion of a removable partial denture (RPD). The oral care and treatment of this patient are described.