Eero Kerosuo

NICKEL ALLERGY IN ADOLESCENTS IN RELATION TO ORTHODONTIC TREATMENT AND PIERCING OF EARS

The aim of this study was to investigate the frequency of nickel hypersensitivity in adolescents in relation to sex, onset, duration and type of orthodontic treatment, and the age at which ears were pierced. The subjects were 700 Finnish adolescents, from 14 to 18 years of age, of which 476 (68%) had a history of orthodontic treatment with metallic appliances. The study consisted of patch-testing for a nickel allergy and a patient history obtained by a questionnaire and from patient record. The frequency of nickel sensitization in the whole group was 19%. Nickel allergy was significantly more often found in girls (30%) than in boys (3%) and in subjects with pierced ears (31%) than in those with no piercing of ears (2%). Orthodontic treatment did not seem to affect the prevalence of nickel sensitization. None of the girls who were treated with fixed orthodontic appliances before ear piercing showed hypersensitivity to nickel, whereas 35% of the girls who had experienced ear piercing before the onset of orthodontic treatment were sensitized to nickel. The results suggest that orthodontic treatment does not seem to increase the risk for nickel hypersensitivity. Rather, the data suggests that treatment with nickel-containing metallic orthodontic appliances before sensitization to nickel (ear piercing) may have reduced the frequency of nickel hypersensitivity.

V. Functions of S‐layers

Although S-layers are being increasingly identified on Bacteria and Archaea, it is enigmatic that in most cases S-layer function continues to elude us. In a few instances, S-layers have been shown to be virulence factors on pathogens (e.g. Campylobacter fetus ssp. fetus and Aeromonas salmonicida), protective against Bdellovibrio, a depository for surface-exposed enzymes (e.g. Bacillus stearothermophilus), shape-determining agents (e.g. Thermoproteus tenax) and nucleation factors for fine-grain mineral development (e.g. Synechococcus GL 24). Yet, for the vast majority of S-layered bacteria, the natural function of these crystalline arrays continues to be evasive. The following review up-dates the functional basis of S-layers and describes such diverse topics as the effect of S-layers on the Gram stain, bacteriophage adsorption in lactobacilli, phagocytosis by human polymorphonuclear leukocytes, the adhesion of a high-molecular-mass amylase, outer membrane porosity, and the secretion of extracellular enzymes of Thermoanaerobacterium. In addition, the functional aspect of calcium on the Caulobacter S-layer is explained.

Subjective need and orthodontic treatment experience in a Middle East country providing free orthodontic services: a questionnaire survey.

The aims of this study were to explore orthodontic treatment experience, subjective need for treatment, and perceptions of teeth and dental appearance in relation to background factors such as funding system, area of living, age, gender, ethnicity, and socioeconomic status. The subjects were 1076 randomly selected second-year high school students from a rural (Jahra) and an urban (Capital) area of Kuwait, with a mean age of 15.1 years. Kuwaiti citizens constituted 79% of the sample, and the rest were of other Arab origins. The data were collected using a questionnaire. Orthodontic treatment rate was significantly higher for Kuwaitis (10%) than for non-Kuwaitis (2%). Among Kuwaiti subjects, urban area of living and female gender increased the odds of receiving orthodontic treatment. Subjective treatment need was 36%, with no difference between Kuwaiti and non-Kuwaiti subjects, but Kuwaitis in the rural area expressed subjective treatment need less often than those in the urban area. The results suggest that access to free-of-cost orthodontic treatment was likely to affect treatment rate, whereas it did not seem to influence the self-perceived need for treatment. Gender and area of living may be significant for the distribution of free-of-cost orthodontic treatment.

Allergic patch test reactions to palladium chloride in schoolchildren

A study of the prevalence of allergic patch test reactions to palladium chloride compared to nickel sulfate was performed in a group of Finnish schoolchildren. All adolescents 14–18 years of age in a Finnish town with 40 000 inhabitants, who had received orthodontic treatment with metallic appliances at a municipal dental clinic, were included in the study. The selection of patients was based on patient records. A non‐treatment control group was randomly selected from the same age groups of the town population. A total of 700 subjects (77% of those invited), 417 (60%) girls and 283 (40%) boys, participated. The majority (91%) of the girls had pieced ears. Orthodontic treatment was equally common (67–70%) in the boys and the girls. The girls had a much higher frequency of allergic patch test reactions to both nickel sulfate and palladium chloride. Of the 700 adolescents tested 48 (7%) had an allergic patch test reaction to palladium chloride. Of the 417 girls, 44 (11%) were palladium‐chloride‐positive, whereas only 4 of the 283 boys tested (1%) had an allergic patch test reaction to palladium chloride 3 patients reacted to palladium chloride only, whereas all other patients with allergic patch test reactions to palladium chloride also had an allergic patch test reaction to nickel sulfate. The results support the concept of cross‐reactivity between nickel sulfate and palladium chloride. The clinical significance of the allergic patch test reactions caused by palladium chloride remains unclear.

Bacteriology of Odontogenic Apical Periodontitis and Effect of Penicillin Treatment

The microbiology and treatment of apical periodontitis was studied in 62 patients, followed-up for 1 year. The clinical treatment and the radiological technique were standardized. One third of the patients received no systemic antibiotics, one third received phenoxymethylpenicillin for 1 week, and one third for 3 months. On the average, 0-2 facultatively anaerobic and 4-6 anaerobic bacteria were isolated from periapical infections. The genera Bacteroides and Fusobacterium in addition to anaerobic gram-positive cocci were found most frequently. Minimum inhibitory concentrations of benzylpenicillin against 269 strains were tested. 12 strains were resistant at the concentration 2.4 micrograms/ml, including 4 strains of Fusobacterium sp. All patients were free of symptoms 1 month after the admission. Only 1 patient failed to show any progress in radiological healing. No differences between the groups in relation to penicillin therapy were found.

Pit and fissure sealants in dental public health – application criteria and general policy in Finland

BackgroundPit and fissure sealants (sealants) are widely used as a non-operative preventive method in public dental health in Finland. Most children under 19 years of age attend the community-organized dental health services free of charge. The aims of this study were to find out to what extent sealants were applied, what the attitudes of dental professionals towards sealant application were, and whether any existing sealant policies could be detected among the health centres or among the respondents in general. The study evaluated changes that had taken place in the policies used during a ten year period (1991–2001).MethodsA questionnaire was mailed to each chief dental officer (CDO) of the 265 public dental health centres in Finland, and to a group of general dentists (GDP) applying sealants in these health centres, giving a total of 434 questionnaires with 22 questions. The response rate was 80% (N = 342).ResultsA majority of the respondents reported to application of sealants on a systematic basis for children with increased caries risk. The criteria for applying sealants and the actual strategies seemed to vary locally between the dentists within the health centres and between the health centres nationwide. The majority of respondents believed sealants had short- and long-term effects. The overall use of sealants decreased towards the end of the ten year period. The health centres (N = 28) choosing criteria to seal over detected or suspected enamel caries lesion had a DMFT value of 1.0 (SD ± 0.49) at age 12 (year 2000) compared to a value of 1.2 (SD ± 0.47) for those health centres (N = 177) applying sealants by alternative criteria (t-test, p < 0.05).ConclusionThere seems to be a need for defined guidelines for sealant application criteria and policy both locally and nationwide. Occlusal caries management may be improved by shifting the sealant policy from the traditional approach of prevention to interception, i.e. applying the sealants over detected or suspected enamel caries lesions instead of sealing sound teeth.

Treatment preferences of deep carious lesions in mature teeth: Questionnaire study among dentists in Northern Norway

Abstract Objective. To investigate preferred treatment methods of deep carious lesions in mature permanent teeth among dentists in Northern Norway. Materials and methods. The survey included all 437 general dental practitioners in Northern Norway working in the private or the public dental health service. The participants received an invitation with a radiograph and a clinical picture of a deep carious lesion in a mature permanent tooth and a questionnaire asking about demographic characteristics and their preferred treatment methods related to different clinical deep caries diagnoses. Results. The response rate was 56%. There was an over-representation of publicly employed dentists among the respondents; otherwise no systematic bias related to non-responders was detected. In the absence of carious exposure and no symptoms, total caries excavation was the preferred treatment method (49%) followed by stepwise excavation (45%). In cases of deep caries and no exposure with symptoms, the preferences were equally distributed between root canal treatment (39%) and stepwise excavation (38%). In the presence of carious exposure but no symptoms, the preferred treatment method was direct pulp capping (51%) and in carious exposure with symptoms root canal treatment was the preferred treatment method (91%). Conclusions. There is no uniform treatment method of deep carious lesions among dentists in Northern Norway.

The three‐dimensional structures of S‐layers of two novel Eubacterium species isolated from inflammatory human processes

The three‐dimensional structures of the crystalline surface layers of two species of Eubacteria have been determined by electron microscopy and computerized image processing. The S‐layer of Eubacterium sp. ES4C has tetragonal symmetry, with a unit cell spacing of 10.6 nm and a thickness of 9.5 nm, while that of Eubacterium sp. AHN 990 has hexagonal symmetry a = b = 15.7 nm and a thickness of 13 nm. The resolutions in the reconstructions were 2.5 nm and 1.8 nm, respectively. The reconstruction of the S‐layer of strain ES4C reveals a distinct domain structure: a major tetramer, arms connecting adjacent unit cells, and a minor tetramer. The S‐layer of strain AHN 990, on the other hand, has a rather complex arrangement, centred around the six‐fold axis.

Ca(OH)2 application modes: in vitro alkalinity and clinical effect on bacteria

AIM To compare five calcium hydroxide (CH) products, CH-gutta-percha Plus points(®) (CHGP) and conventional CH paste, for their ability to maintain alkalinity and to assess the clinical antimicrobial effect of CHGP. METHODOLOGY Calcium hydroxide products were tested in the presence of standardized dentine powder or by titrating them with 1 mol HCl, expressed in mL (±SD). In a clinical trial, 21 single-rooted teeth with primary apical periodontitis were medicated with CHGP or with conventional CH paste. Bacterial samples were taken before and after chemo-mechanical preparation, after dressing and after leaving canals empty but sealed. To compare groups, anova with Tukeys test was used in the laboratory study and Fishers exact test in the clinical study. Significance level was set at 5%. RESULTS Pure CH with water (8.5 ± 0.1) and Calasept (9.3 ± 0.1) maintained the highest alkalinity, followed by the gel-like products DS CaOH gel (7.3 ± 0.3) and Ultracal XS (6.8 ± 0.2) and then Biokalkki (6.3 ± 0.3) and Calxyl blue (5.1 ± 0.2). All CH paste products had higher values compared with CHGP (1.6 ± 0.1) (P < 0.05). Saturated solutions of the products were all neutralized to pH 8.6 within 24 h by dentine powder addition. Clinically, culture-negative results were obtained in 5/10 canals in the CHGP group and 7/11 with conventional CH (P > 0.05). CONCLUSIONS Aqueous CH mixtures kept high pH better than viscous gel products or CHGP. Dentine powder had equal buffering effect on each product tested. CHGP and traditional CH paste both had an antimicrobial effect in the clinical setting, but there was no significant difference between the groups.

Ultrastructural Comparison of Bacteroides heparinolyticus and Bacteroides buccae

Bacteroides buccae is among the few human oral species reported with an S-layer (Kornman and Holt 1981). The periodic arrangement of the lattice has been reported to be hexagonal (Ranta et al. 1983, Haapasalo et al. 1985, Sjogren et al. 1985).