BACKGROUND: The mint flavour carvone (l-carvone) is considered a weak contact allergen. However, contact allergy to carvone is more prevalent in patients with oral lichen planus or oral lichenoid lesions (OLP/OLL).

OBJECTIVE: Our aim was to investigate how carvone affects sensitized individuals through a use test with toothpaste containing carvone. Non-flavoured toothpaste served as control.

METHODS: Subjects were patch tested prior to the use test-14 subjects allergic to carvone (11 with OLP/OLL), 20 subjects with OLP/OLL and 3 healthy controls. The month-long use test comprised of using toothpaste twice daily. Subjects were examined fortnightly. Clinical signs were assessed with a mucosal scoring system. The subjects' oral health-related quality of life was measured with the oral health impact profile (OHIP-49).

RESULTS: Local reactions to the carvone toothpaste presented as aggravated OLL (7/10) and peri-oral eczema (2/10) in allergic subjects. They also had significantly higher mucosal and OHIP scores compared with those receiving non-flavoured toothpaste.

CONCLUSION: In sensitized individuals, oral exposure to carvone gives aggravated oral lesions and/or peri-oral eczema. The lesions mimic OLP and allergic individuals are therefore at risk of not being assessed with regard to flavour contact allergy.

Purpose: To assess the clinical outcomes of maxillary overdentures supported by dental implants by conducting a literature review. Materials and Methods: An electronic search was undertaken in March 2019. Eligibility criteria included publications reporting cases of implant-supported maxillary overdentures with follow-up information. Results: A total of 131 publications were included (1,478 overdentures supported by 6,681 implants). The mean number of attachments per overdenture was 3.8 ± 1.2 (range: 1 to 9), and a bar-clip system was used in about half of the cases. The prostheses were followed up for a mean of 47.9 ± 32.8 (range: 1 to 240) months. A total of 401 implants (6.0%) failed in 219 patients (14.8%), and 55 prostheses (3.7%) failed at a mean of 40.2 ± 53.2 (range: 6 to 240) months after placement. Most of the failures happened within the first year after placement for both implants (52.1%) and prostheses (41.8%). Patients with fewer implants per prosthesis presented higher prosthesis failure rates than patients with more implants per prosthesis. The cumulative survival rate for dental implants after 19 years was 70.4%, and for implant-supported maxillary overdentures was 79.8%. Presence of palatal coverage and/or metallic structure/reinforcement does not seem to have an influence on failure rate. Of the most commonly used attachment systems, the ball/O-ring and the Ceka were the ones with the highest rates of patients having at least one implant failure. Conclusion: Most of the prosthesis failures were due to loss of implants, and the first year was the most critical period for failures. The number of dental implants placed per patient seemed to have an impact on the occurrence of overdenture failure.

PURPOSE: To validate the well-known and often-used impression replica technique for measuring fit between a preparation and a crown in vitro. MATERIALS AND METHODS: The validation consisted of three steps. First, a measuring instrument was validated to elucidate its accuracy. Second, a specimen consisting of male and female counterparts was created and validated by the measuring instrument. Calculations were made for the exact values of three gaps between the male and female. Finally, impression replicas were produced of the specimen gaps and sectioned into four pieces. The replicas were then measured with the use of a light microscope. The values received from measuring the specimen were then compared with the values received from the impression replicas, and the technique was thereby validated. RESULTS: The impression replica technique overvalued all measured gaps. Depending on location of the three measuring sites, the difference between the specimen and the impression replicas varied from 47 to 130 mum. CONCLUSION: The impression replica technique overestimates gaps within the range of 2% to 11%. The validation of the replica technique enables the method to be used as a reference when testing other methods for evaluating fit in dentistry.

Carvone (l-carvone), a mint flavour in spearmint oil, is considered a mild skin sensitizer. Carvone-sensitization may be linked to oral/perioral signs and oral lichen planus, but studies are sparse. The prevalence of patch test reactions to carvone and relevant findings from the positive group were investigated. Records for patch-tested patients at the Malmö clinic, for the period 1996 to 2016, were studied. Carvone-positive and carvone-negative patients were compared regarding patch test data from baseline series and dental series. Dental series-tested carvone-positive patients were also compared with a matched group. A total of 147 out of 4,221 referred patients had a positive patch test to carvone. Sensitized patients had higher mean age and were primarily women; 73% had oral signs and 57% had oral lichen. Concomitant patch test reactions to gold, nickel and mercury were common. In the matched group-comparison carvone-positive patients had a higher frequency of oral lichen, but no difference was found in sensitization to gold and mercury.

BACKGROUND: Toothpastes have widespread use in the population, and contain flavours used to give a pleasant and often minty aroma. Flavours are prevalent allergens in toothpastes, and adverse reactions often present as perioral dermatitis or stomatitis. l-Carvone, a mint flavour found in spearmint oil, is one of these allergens. There are few studies on contact allergy to l-carvone, and some of them have indicated a positive relationship with oral lichenoid lesions. OBJECTIVES: To qualitatively and quantitatively investigate the presence of l-carvone in commercially available toothpastes on the Swedish market. METHODS: l-Carvone in 66 toothpastes was analysed with straight-phase high-performance liquid chromatography. The product labels were studied with regard to limonene. RESULTS: l-Carvone was found in 64 of 66 toothpastes (concentration: 0.00005-0.35%). In 10 of these, the concentration exceeded 0.1%. Higher concentrations of l-carvone were found if limonene was listed on the label. CONCLUSION: The majority of toothpastes on the Swedish market contain l-carvone, but the concentration hardly relates to the advertised flavour or labelled ingredients. It is hitherto unknown whether the found concentrations are sufficient for induction of contact allergy in individuals with healthy oral mucosa or in those with oral lichenoid lesions or other mucosal disease.

A predominant part of the Swedish population uses toothpaste daily. Besides fluoride preventing caries, toothpastes usually have flavours added to make the user feel fresh and clean. Among potential allergens in toothpastes, flavours are the most common cause of oral or perioral lesions. Flavour concentrations vary between 0.3% and 2.0%, and usually several types of mint are used; however, the true composition of the added aroma is seldom known. l‐Carvone is a mint‐tasting flavour that can act as a potential allergen. Previous findings have shown that approximately 4% of a patch‐tested selected population in southern Sweden had a positive reaction to l‐carvone and half of them had oral inflammatory lesions, notably oral lichenoid lesions. Among patients with lichenoid lesions approximately 12% have a contact allergy to l‐carvone and several other contact allergies are more common in this patient group. The concentration of l‐carvone in toothpastes available for sale on the Swedish market was investigated. Sixty‐six different toothpastes were selected from local stores and pharmacies. l‐Carvone content was extracted from toothpastes using n‐heptane. The sample extracts were separated on a silica column using straight‐phase high‐performance liquid chromatography and a diode‐array detector. Three samples of each toothpaste were analysed, and the mean concentration and relative SD were calculated. Detectable levels of l‐carvone (0.00005–0.35%) were found in 63 of the toothpastes. l‐Carvone was found in half of the toothpastes (n = 32) at a concentration of ≥ 0.01%. A higher concentration (≥ 0.1%) was found in 18% (n = 12). Of the top six toothpastes with highest l‐carvone content (0.15–0.35%), one was intended for use by children. Two of the toothpastes were stated as having fruit flavour, but there were still detectable levels of l‐carvone (0.0003% and 0.00007%, respectively). l‐Carvone was below detectable levels in three of the toothpastes, where one was stated as being without flavour. l‐Carvone is present in virtually all toothpastes on the Swedish market. It is therefore likely that l‐carvone in toothpastes is important for the induction of sensitization to l‐carvone, as contact allergy to l‐carvone is over‐represented in patch‐tested individuals with oral lichenoid reactions. However, are the concentrations demonstrated relevant for causing reactions or aggravating already existing lesions?

Background: Carvone (L-carvone) is naturally found in spearmint oil and is considered a mild skin sensitizer. It commonly serves as a flavoring agent in toothpaste and other mint tasting products. There is recent evidence that carvone may have a relationship with oral lichenoid lesions (OLL). Objectives: The aim was to study the frequency of carvone contact allergy in a Swedish patch test population at the Malmö clinic and to investigate the characteristics of the group with special reference to OLL. Methods: A 15-year retrospective study including all consecutive patients tested positive for carvone with different series containing carvone. The patients’ records were reviewed in regard to symptoms, previous diagnoses, type of referrer and contact allergy. Results: Three thousand eight hundred and twelve patients were patch tested to different series containing l-carvone, the most common being the Swedish dental series. One hundred and forty-three patients (3.7%) were positive to carvone whereof 138 patients had records available for review. Of the carvone-sensitized patients, 46.9% had suspected or previously diagnosed OLL and 8.0% had dermal or genital lichen planus. The majority of the carvone-sensitized patients had also positive reactions to several other allergens. The most common allergens were spearmint oil (39.9%), gold (35.5%) fragrance-mix (17.4%) and nickel (15.5%). The majority of the carvone-sensitized patients with allergy to gold (30/49) or allergy to mercury (16/18) also had OLL. The male-to-female ratio was 1:4.75 among the carvone-sensitized patients compared to 1:2.55 in the overall test groups. Conclusions: The frequency of patients sensitized to carvone seems to correspond with previous findings. Concomitant contact allergy to gold or mercury was often associated with OLL and these patients were often referred for suspected allergy from d ental restorations. The data together with conclusions in recent reports suggests a relationship between OLL and l-carvone contact allergy. The relationship is yet unknown and needs further investigation.

The aim of the present controlled study was to investigate a possible relationship between contact allergies to potential allergens and oral lichen lesions. Eighty-three patients with oral lichen lesions (OLL) and control groups of age- and gender-matched dermatitis patients (DP, n = 83) and patch-tested dermatitis patients randomly selected from files (PSFF, n = 319) were included in the study. OLL and DP groups were patch-tested epicutaneously and examined intraorally. The frequencies of contact allergy to mercury and carvone were statistically higher in the OLL group than in the DP group. Surfaces of amalgam and composite restorations were statistically more frequent in the OLL group compared to the DP group. Contact allergy to nickel and colophony, the latter with a statistically significant difference, was more common in the DP group. The numerical difference found for nickel allergy was, however, not significant comparing the OLL and PSFF groups. Contact allergy to mercury was overrepresented in patients with OLL and has been reported in previous studies, but the present finding of an overrepresentation of contact allergy to carvone in patients with oral lichen lesions has not been reported previously. Carvone, in addition to mercury and gold, as previously suggested, can be one of the causative or maintenant factors for oral lichen lesions. Carvone-hypersensitive patients with oral lichen lesions should therefore avoid carvone-containing products for oral use.

Establishing the clinical relevance of contact allergy to dental materials in patients with oral lichen lesions (OLL) may be difficult, and tests are often read only on day 3 or day 4; also, concentration of the tested allergens may vary. Several studies on dermatitis patients have shown that additional positive patch test reactions can be found after day 4. Therefore, the aim of the present study was to analyse the frequency of late positive reactions to potential allergens in patients with OLL. Eighty-three of 96 consecutive patients with biopsy-verified OLL were patch-tested with a recently developed lichen series. The patches were removed after 48 h and reactions read 3 and 7 days after application. A total of 129 contact allergies were found, and 26 (20.2 %) of the allergic reactions in 23 patients were seen on day 7 only. The 25.2 % increase in positive test reactions with an additional reading on day 7 in addition to day 3 was statistically significant. Metals were the substances with the highest frequency of late positive reactions. Patients with OLL cannot be considered properly investigated with regard to contact allergy, unless the testing has been performed with mandatory readings on day 3 (or day 4) and day 7. Late patch test readings are crucial in order to elucidate the role of contact allergy to dental materials in the aetiology of OLL.