Contact dermatitis and adverse oral mucous membrane reactions related to the use of dental prostheses

The latest trends in the use and composition of dental prostheses have been reviewed, and 66 patients referred by dermatologists and odontologists patch tested. The allergen series used were: TRUE Test standard series; Chemotechnique dental screening series; specially prepared metals series. The allergens found to be positive, in order of frequency, were: nickel, cobalt, potassium dichromate, rhodium, palladium, mercury, beryllium, methyl methacrylate, copper and zinc.

Identification of causative chemicals of allergic contact dermatitis using a combination of patch testing in patients and chemical analysis. Application to cases from rubber footwear

5 cases of allergic contact dermatitis from rubber footwear were investigated by a combination of patch testing in patients and chemical analysis of causative rubber products. Our studies revealed 2-mercaptobenzothiazole (MBT) and benzothiazyl disulfide (MBTS) (typical allergenic accelerators) as causative chemicals in 3 cases from children's rubber shoes, ladies' rubber boots and ladies' canvas shoes. These 3 patients reacted to mercaptobenzothiazole-type accelerators including MBT and MBTS. MBT and MBTS were determined in each item of causative footwear by chemical analysis, including extraction by shaking with acetone-chloroform (1:1) mixture at room temperature and determination using reversed-phase high-performance liquid chromatography (RP-HPLC). Subsequently, we identified styrenated phenol (SP), a newly found allergenic antioxidant, as a causative chemical in a case from ladies' canvas shoes. The patient reacted to SP but not to MBT and MBTS, though SP, MBT and MBTS were determined in the causative shoes by gas chromatography (GC), GC-mass spectrometry (GC-MS) and HPLC. We also identified p-tert-butylphenol-formaldehyde resin (PTBP-F-R), (a known allergenic adhesive ingredient) as a causative chemical in a case from ladies' sneakers. The patient reacted to PTBP-F-R but not to p-tert-butylphenol (PTBP), MBT and MBTS. These 4 compounds were determined in the causative sneakers by GC, GC-MS and HPLC. Thus, our studies revealed that not only known allergens, such as MBT, MBTS and PTBP-F-R, but also a newly found one, such as SP, were important causes of allergic contact dermatitis from rubber footwear.

Hypersensitivity pneumonitis-like reaction among workers exposed to diphenylmethane [correction to piphenylmethane] diisocyanate (MDI)

Isocyanates are well documented as a cause of occupational asthma. A hypersensitivity pneumonitis type of reaction has also been reported but only in a few isolated cases. We investigated nine subjects who complained of respiratory and general symptoms related to workplace exposure. All the subjects had worked in a plant where a resin based on diphenylmethane diisocyanate (MDI) is used in the manufacture of woodchip boards. They underwent inhalation challenges using the MDI resin for progressively increasing periods of time on separate days. In eight subjects, exposure to subirritant amounts of MDI induced a pattern of reaction consistent with hypersensitivity pneumonitis, i.e., significant falls in both FEV1 and FVC associated with a rise in body temperature (> 38 degrees C) and an increase in blood neutrophils (> +2,500/mm3). Bronchoalveolar lavage, performed in two subjects 24 h after the end of challenge exposure, revealed an increase in lymphocytes and neutrophils. Specific immunoglobulin G (IgG) and IgE antibodies to MDI human serum albumin (HSA) conjugates were present in all subjects. We conclude that the MDI resin caused an hypersensitivity pneumonitis type of reaction in at least eight (4.7%) of the 167 potentially exposed workers employed in the plant. These findings indicate that in some workplaces, a hypersensitivity pneumonitis type of reaction may be a more frequent consequence of isocyanate exposure than is usually thought.

Biocompatibility of polyoxymethylene (Delrin) in bone

The bone tissue reaction to bulk polyoxymethylene (Delrin) was studied in eight adult albino rabbits followed for up to 5 months after insertion of implants into the tibial metaphyses. Each animal received two implants, one of pure Delrin, the other a 'mosaic' plug with alternating areas of commercially pure titanium and Delrin. At the passage through the cortex, a direct bone-Delrin contact was seen in more than half of the cases, but the contact was usually limited in extent. At the same time, in virtually all sections, a foreign-body reaction with macrophages and giant cells was prominent. It was concluded that bulk Delrin has inferior biocompatibility to titanium, and the advisability of using Delrin as a biomaterial for bone anchorage is questionable.

Bond strength of resin to dentin treated with calcium phosphate desensitizer

In a previous study we proposed a new method utilizing immediate precipitation of calcium phosphate (CaP) in situ for treatment of dentin hypersensitivity. Sequential application of 5% disodium phosphate followed by 10% calcium chloride on patent dentin surface resulted in instant occlusion of dentin tubules and immediate relief from the hypersensitivity. To guarantee long-lasting effectiveness of the CaP treatment, resin coverage of the treated dentin surface will be the next practical approach. However, the CaP covering the surface may possibly affect bonding of resins. This study determined the effect of the CaP treatment on tensile bond strength of adhesive resins to dentin. Independent of the type of resin used, a bond strength of 4-5 MPa was obtained; cohesive failure occurred within the resin-CaP hybridized composite layer rather than at the dentin surface. The CaP treatment produced a significant increase in the bond strength of one resin.

Allergic contact dermatitis from formaldehyde resins in permanent press clothing: an underdiagnosed cause of generalized dermatitis

BACKGROUND AND METHODS

Formaldehyde resins have been used to impart wrinkle resistance to clothing fabrics since 1926. After several patients with positive patch tests to formaldehyde resins had been examined, a study was undertaken of the records of all patch tests performed at the University of Louisville Patch Test Clinic and the Allergy Section of the Skin and Cancer Clinic of New York University Medical Center from January 1988 through April 1990 to determine the prevalence of positive patch-test reactions to formaldehyde-based textile resins and the clinical and demographic patterns associated with textile resin allergy.

RESULTS

Seventeen patients were identified at the two centers. Twelve were allergic to formaldehyde as well as to formaldehyde textile resins. Several clinical patterns were found, including accentuation of dermatitis in areas of tight clothing, primary occurrence in clothing-covered areas, and a chronic recalcitrant course. Ethylene urea melamine formaldehyde resin was the best screening agent with 14 definite positive reactions and one equivocal reaction.

CONCLUSION

Formaldehyde textile resin allergy is more common than has been previously recognized. Patch testing with one or more formaldehyde textile resins is indicated in patients with a particular pattern of dermatitis.

Usage test of four endodontic sealers in Macaca fascicularis monkeys

Root canals with vital pulps in four Macaca fascicularis monkeys were subjected to pulp extirpation and root filling with gutta-percha and sealer, either AH26, Endomethasone, Kloroperka N-phi, or ProcoSol. Observation periods were 1 and 6 months. The results of treatment were evaluated by radiographic analysis (periapical index scores) and by histopathologic assessment of the remaining pulp and periapical tissues. Sixty roots with acceptable termination (between 0.5 and 3 mm from apex) of the root fillings and adequate histopathologic specimens were available for analysis. These roots were equally distributed in each observation period group and among the four material groups. Radiography indicated periapical pathosis in 6 of the 60 roots--4 at 1 month and 2 at 6 months. Periapical inflammation was observed on histopathologic examination in 17 roots--11 after 1 month and 6 after 6 months. Histologic and radiographic assessment of periapical inflammation was significantly correlated (p less than 0.01, chi 2) at the 6-month observation period. No granuloma or cyst formation was evident on histologic examination. The magnitude of the inflammatory response appeared unrelated to the endodontic sealer used, and several inflammatory foci were not related to foreign bodies in the tissues. Bacteriologic sampling showed growth in thioglycollate broth cultures in 9 of the 60 roots, but the presence of cultivable bacteria by this technique was unrelated to inflammatory changes. Histologic demonstration of bacteria was positive in 4 roots, all of which were associated with inflammatory periapical reactions. The method applied in the present study did not provide a sensitive discrimination among endodontic materials of widely different chemical composition.

[A new resinifying solution without the effect of discoloring teeth]

In order to solve the problem of tooth stain caused by phenolformaldehyde resinifying therapy, we have, on basis of theory of the resinifying therapy, prepared a colourless resinifying solution RF-109. Experiments on its chemical and physical properties, ability of becteriostasis, animal tissues reaction including ultra-structure observation after resinified muscles of rats, rabbits and dogs as well as imitate root canal filling have been performed. Results proved that RF-109 is desirable for resinifying therapy. Its peculiarity is that after pulp therapy, the tooth will not be stained. And besides, it is much simpler in preparation, and lower in cost than that of phenol-aldehyde resin. Its preservation is also much easier. The long-term results of RF-109 is satisfactory in 91.30% of 174 cases followed-up for three years.

Impeded lung function in moulders and coremakers handling furan resin sand

A total of 39 moulders and coremakers exposed to furan resin sand and 27 unexposed local controls were examined by lung-function tests before and after a work shift. In all, 28 of the subjects exposed to furan resin sand and the control group were evaluated by dynamic spirometry and nitrogen washout. The remaining 11 subjects exposed to furan resin sand were studied using both static and dynamic spirometry and the CO single-breath technique. The time-weighted average exposure to furfuryl alcohol was about 7 mg/m3, with peak values exceeding the present Swedish short-term exposure limit (40 mg/m3). The exposure to respirable dust and formaldehyde as time-weighted over the shift was less than 2 mg/m3 and 0.4 mg/m3, respectively, in all groups. During the work shift studied, the 28 exposed subjects had more complaints of airway symptoms than did the controls, showing an average decrease of 0.21 in forced vital capacity but no fall in any other lung-function variable. The remaining 11 exposed subjects demonstrated a post-shift decrease in total lung capacity. The results indicate an acute restrictiveness induced by exposure to furan resin sand, but the underlying mechanism is unclear. Chronic impairment of lung function was not observed.

Allergic contact dermatitis from para-tertiary-butylphenol-formaldehyde resin (PTBP-FR) in athletic tape and leather adhesive

4 girls with severe allergic contact dermatitis from a brand of athletic tape and a cobbler with allergic contact dermatitis from leather adhesive are presented. Alkylphenol resin with unknown chemical structure had been compounded in both products. One of the girls developed foot dermatitis later from the adhesive used on the inside of new sneakers. By patch testing and chemical analysis of alkylphenol resin and the products, the 5 patients were given a specific diagnosis of allergic contact dermatitis from PTBP-FR.

Post-insertion sensitivity with a bonded etched cast metal prosthesis. Case report

An interesting case of post-insertion sensitivity in a patient who had an etched cast metal prosthesis (Maryland Bridge) cemented with a recently marketed resin luting agent is discussed. This case report draws attention to the fact that despite the relative conservatism and simplicity commonly associated with abutment tooth preparation for resin bonded prostheses, dentine exposure should be avoided if possible to reduce the potential for chemical irritation of the pulp by components of the resin luting system.

[Epidemiology of contact hypersensitivity to rubber components in manufacturers of automobile tires at the Stomil plant]

Dermatological examination and patch tests with 34 rubber components were carried out in 114 tire manufacturers, 78 women and 36 men aged 29 years on average, with a mean duration of work in the plant 7 years. For correct interpretation of the obtained results patch tests with the same components were done in two control groups that is in 120 healthy subjects and 120 patients with contact dermatitis. Patch tests with proper concentrations of the studied components were evaluated after 48, 72 and 96 hours. Positive patch tests were found most frequently with antioxidants--16.6% (including IPPD--8.6%), followed by vulcanization accelerators--10.6%, and other rubber components--11.4% in all. During about 3 years of follow-up in 4 manufacturers contact allergic eczema was noted and polyvalent hypersensitivity to antioxidants and vulcanization accelerators without clinical manifestations of this hypersensitivity was diagnosed in 3 other subjects.

Assessment of adverse reactions to prosthodontic materials

In 1978 five cases of so-called hypersensitivity reactions to Scutan and two to Impregum were reported (Dahl, 1978). The aim of the present study was to assess whether hypersensitivity or cell-mediated immune reactions were associated with the adverse clinical reactions in these patients or in others who had experienced the same reactions. Epicutaneous patch testing and lymphocyte transformation tests were carried out in a total of 13 individuals. The findings were difficult to interpret, because there was no consistent association between skin reactions and cell-mediated immune responses in subjects with suspected allergies. Other possible reasons for the reactions originally recorded were therefore discussed. It was concluded that adverse reactions associated with immune-mediated, delayed type hypersensitivity reactions may be elicited by prosthodontic materials, but other pathogenic mechanisms and aetiological factors responsible for the reactions observed should also be considered.