Capping carious exposures in adults: a randomized controlled trial investigating mineral trioxide aggregate versus calcium hydroxide.

AIM: The aim of this multicentre, parallel-group randomized clinical trial was to compare the effectiveness of mineral trioxide aggregate (MTA) and a conventional calcium hydroxide liner (CH) as direct pulp capping materials in adult molars with carious pulpal exposure. METHODOLOGY: Seventy adults aged 18-55 years were randomly allocated to two parallel arms: MTA (White ProRoot, Dentsply, Tulsa Dental, Tulsa, OK, USA; n = 33) and CH (Dycal® , Dentsply DeTrey GmbH, Konstanz, Germany; n = 37). The teeth were temporized for 1 week with glass-ionomer (Fuji IX, GC Corp, Tokyo, Japan) and then permanently restored with a composite resin. The subjects were followed up after 1 week and at six, 12, 24 and 36 months. The primary outcome was the survival of the capped pulps, and the secondary outcome was postoperative pain after 1 week. Survival was defined as a nonsymptomatic tooth that responded to sensibility testing and did not exhibit periapical changes on radiograph. At each check-up, the pulp was tested for sensibility and a periapical radiograph was taken (excluding the radiographs taken at the 1-week follow-up). Kaplan-Meier survival analysis and log-rank test were used to assess the significant difference in the survival curves between groups. Chi-square test was used to assess the association between the materials and preoperative and postoperative pain. RESULTS: At 36 months, the Kaplan-Meier survival analysis showed a cumulative estimate rate of 85% for the MTA group and 52% for the CH group (P = 0.006). There was no significant association between the capping material and postoperative pain. CONCLUSIONS: Mineral trioxide aggregate performed more effectively than a conventional CH liner as a direct pulp capping material in molars with carious pulpal exposure in adult patients. This study has been registered at ClinicalTrials.gov, number NCT01224925.

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 Tukey's test was used in the laboratory study and Fisher's 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.

A comparative study on the disinfection potentials of bioactive glass S53P4 and calcium hydroxide in contra-lateral human premolars ex vivo.

AIM: To evaluate the effects of bioactive glass S53P4 versus calcium hydroxide when used as dressings in contra-lateral human premolars infected with Enterococcus faecalis ATCC 29212. METHODOLOGY: Pairs of contra-lateral premolar teeth plus single control premolars were obtained from 23 individuals aged 10-26 years undergoing orthodontic treatment. Root canals of teeth with fully formed apices (nine contra-lateral pairs, seven controls) were instrumented using a size 60 FlexoFiles 2 mm short of canal length. Canals with open apices (six contra-lateral pairs, four controls) were circumferentially instrumented using a FlexoFile. Root canals were rinsed with 1% sodium hypochlorite and 10% citric acid. Teeth were then suspended in tryptic soy broth (TSB) and autoclaved. Positive controls and study teeth were infected with E. faecalis ATCC 29212 for 2 weeks in TSB, while negative controls were kept in sterile TSB. Subsequently, contra-lateral premolars were dressed with bioactive glass S53P4 (BAG) or calcium hydroxide suspensions for 10 days. Dentine samples were obtained from teeth with fully formed apices using ISO-size 70, 80 and 90 FlexoFiles to working length and cultured. Teeth with open apices were fixed, fractured and examined using scanning electron microscopy (SEM). RESULTS: Calcium hydroxide had a strong antibacterial effect and was significantly more effective than BAG in preventing residual bacterial growth (P < 0.01). SEM analysis revealed apparent substance-specific modes of action. CONCLUSIONS: Calcium hydroxide was an effective disinfectant in human teeth.

The atraumatic restorative treatment (ART) approach to restoring primary teeth in a standard dental clinic.

OBJECTIVES: The aims of this study are to assess the feasibility of the Atraumatic Restorative Treatment (ART) approach in primary teeth and to compare the ART approach with traditional amalgam restorations in primary molars. METHODS: This study was conducted in a paediatric dentistry clinic in Kuwait between April 1999 and December 2001. The ART and amalgam restorations were placed randomly on comparable pairs of primary molars, if available. In addition, the ART approach was used for other primary teeth that had no pulpal involvement and no perceived pain before treatment. The restorations were assessed by both the ART evaluation criteria and USPHS criteria in August-September 2000 and in August-December 2001. The mean follow-up period for the restorations was 8.3 months in the first assessment (2000) and 22 months in the second assessment (2001). The assessment was possible for 35 children (mean age = 5.7 years), 18 of whom had comparable pairs (n = 35 pairs) of restorations in their primary molars. In addition, 48 other ART restorations were assessed in 2000 and 42 in 2001. RESULTS: In a 2-year follow-up, 89.6% of all ART restorations were considered successful. The failure rate of the comparable pairs of ART and amalgam restorations was 5.7%. There was no significant difference in success rate between ART and amalgam techniques. CONCLUSIONS: Based on a 2-year follow-up evaluation, the class I ART restorations seemed to have a high success rate, indicating the appropriateness of the ART approach in primary teeth.

A 13-year follow-up of a comprehensive program of fissure sealing and resealing in Varkaus, Finland.

The objective of the study was to examine the coverage of the sealing program on first permanent molars (FPMs) and second permanent molars (SPMs) and first and second premolars (FSPMs), as well as to monitor the fate of the sealed teeth over time. All patients born in 1977 who had had regular check-ups in the Varkaus Health Center, Finland (n = 166) were included in the 1996 study. Data on the annual state of each tooth had been collected retrospectively since 1983. The coverage for the sealant program was 95%, 92%, and 6% of the FPMs, SPMs, and FSPMs, respectively. Out of the FPMs sealed at age 6 years, 28% were subjected to resealing, 13% developed occlusal, and 15% proximal caries during a 13-year follow-up period. From the SPMs sealed at age 11 years, 24% were subjected to resealing, 4% developed occlusal caries, and less than 2% proximal caries during the 9-year follow-up. None of the sealed FSPMs and only 1% of the non-sealed ones developed occlusal caries during the 9-year period. The mean DMF in the study population (n = 160) at age 12 years was 0.8 (n = 124), compared to a nation-wide mean value of 1.2. A large percentage of the FPMs and SPMs were sealed and then resealed during the study period. Although the study design lacked a control group for comparison, the lower caries rates of this study compared to the results of other studies with only a single application of sealants suggest a major role for resealing.

Report on the development of a new dental curriculum at Helsinki.

A review of the dental curriculum was undertaken in Helsinki in the mid 90s. The objectives of the new curriculum were to reinforce the links between basic biomedical and dental sciences in order to give more emphasis to oral medicine and comprehensive dental care. Furthermore, the curriculum needed to promote an interdisciplinary approach and encourage students to understand dental diseases in relation to the community at large. A two-year, topic-based, preclinical curriculum, fully integrated with medical students, was started. For didactic teaching in the clinical phase, new learning entities were established to promote an inter-disciplinary approach. For the first time in Finland, objectives were formulated for attitudes and interpersonal skills. Clinical training was conducted in a comprehensive clinic, based on the team concept, where emphasis was given to proven competency instead of to the number of procedures performed. The time spent in the clinic was kept the same as previously (1440 h). Students' learning process was assessed with a portfolio. The majority of students welcomed the comprehensive care clinic, especially its team concept and treatment planning seminars. However, feedback seminars after treatment of the patient were not in favour. As part of the evaluation process, a DENTED visitation took place in Helsinki in March 1999. The results obtained in the student questionnaire were consistent with the aims of the undergraduate training and with the present patient treatment range. In conclusion, the curriculum change enabled the school to broaden the biomedical aspects by increasing the period of preclinical studies. Although the extent of these studies was greater than in the past, and meant postponement of clinical skills courses by one semester, it did not jeopardise the competency in clinical dentistry, owing to the effective integration of the clinical phase teaching.

The need for treatment and satisfaction with dental appearance among young Finnish adults with and without a history of orthodontic treatment.

The aim of this investigation was to evaluate orthodontic treatment need and patient satisfaction among young adults living in a city where free-of-charge orthodontic treatment was provided. A total of 281 18- to 19-year-old subjects randomly selected from the population register of the city of Vantaa took part in the study. The drop-out rate was 30%. Treatment need was clinically assessed according to the Index of Orthodontic Treatment Need (IOTN), consisting of a Dental Health Component (DHC) and an Aesthetic Component (AC). Information on previous orthodontic treatment was based on the patient records. Satisfaction of the subjects with their dental appearance and with the orthodontic treatment received was obtained using a questionnaire. The rate of orthodontic treatment among the subjects was 46% (54% for the females and 37% for the males, p < 0.05). 4% had discontinued treatment. A definite need for treatment (DHC 4 to 5/AC 8 to 10) was assessed in 15% of the subjects, and borderline/moderate need (DHC 3/AC 5 to 7) in 36%. No difference in IOTN scores between the treated and untreated subjects was found. Females had significantly more often no treatment need (DHC 1 to 2/AC 1 to 4) compared with males (p < 0.05). The majority of subjects (89%) reported that they were very or quite satisfied with their dental appearance. The odds of being satisfied were significantly higher for the treated subjects (OR = 2.71, p < 0.05) and lower for those at the non-attractive end of the AC scale (OR = 0.14, p < 0.01). Neither gender nor DHC grade significantly affected the odds of being satisfied among the subjects. The results indicate that the majority of young adults in this study were satisfied with their dental appearance regardless of objective treatment need of various degrees. The high treatment rate in relation to unnoticed treatment need calls for reevaluation of priorities in patient selection.

Quality evaluation of process of root canal treatments performed on young adults in Finnish public oral health service.

OBJECTIVES: To evaluate the quality of root canal treatments performed in every-day practice on young adults. METHODS: A quality index related to the treatment process was developed based on the guidelines of the European Society of Endodontology. A random computerised selection of 134 young adults (born 1966-1971) produced 125 (93%) eligible oral health documents, including information on 148 teeth that were root canal treated by 47 dentists. The process of root canal treatment was evaluated according to the original oral health documents. The technical quality of root canal fillings was assessed on postoperative periapical radiographs. RESULTS: The overall Kappa statistics for the inter-examiner reliability of assessments was 0.63; the proportional agreement being 87%. The mean quality index was 6.2, s.d. 2.0, with none of the treatments scoring the maximum 13. On the 56 available postoperative radiographs, 52% of the fillings were optimal, showing a length within 0-3mm from the radiological apex, no voids in the apical part nor lumen apical to the filling. Of the completed 144 root canal treatments, only 11 included some recorded follow-up information within 15months from the termination of the treatment. CONCLUSIONS: The technical quality of the root fillings was similar to that found in previous studies. However, the quality index, paucity of pre- and post-operative radiographs, and the lack of follow-up all indicated a discrepancy between consensus guidelines and every-day practice.

Self-reported health complaints among general dental practitioners, orthodontists, and office employees.

Studies in the Scandinavian countries have shown that orthodontists run an equal or even greater risk of contracting dermatitis compared to other dental personnel. The aim of the study was to find out whether the self-reported occupation-related health problems of general dental practitioners and orthodontists differ from those of office employees in Finland. The subjects were 147 general dentists, 81 orthodontists and 99 office employees (77% women and 23% men). The data were collected using a mailed questionnaire. Within the past year, 42% of the subjects had had occupational health problems, while 51% had experienced symptoms in the previous year or earlier. The complaints of hand dermatoses, musculoskeletal, as well as respiratory symptoms were significantly more common among women than among men. Musculoskeletal complaints were the most common symptoms in all occupational groups, but the odds ratio of having them were significantly higher for dental professionals compared to office employees. The frequency of self-reported hand dermatoses was 42% for dental professionals and 26% for office employees, but the difference did not reach statistical significance. The odds of having hand dermatoses were higher for atopic subjects and for women. Orthodontists did not differ from general practitioners in respect of any of the complaints reported. Materials used in dentistry were mentioned as the cause of symptoms by 49 (21.5%) of the dental professionals. The present results show an increased risk of self-reported musculoskeletal symptoms for the dental professionals. Also, a tendency towards increased occurrence of skin symptoms was noted for the dental professionals compared to office employees of this study.

Can Glass ionomer sealants be cost-effective?

Glass ionomer (GI), applied as a pit and fissure sealant, has been shown to be a promising method for caries prevention. It has also been suggested that when GI is used as a sealant material, it can prevent caries, even if partly or totally lost. As there is no need for resealing GI, it may be more cost-effective when compared to a resin-based (RB) sealant. This study evaluated the factors influencing the time needed to apply a sealant as a factor in determining the possible costs of the effectiveness of RB compared to GI sealants. To study this, children born between 1980 and 1983, who had their appropriate second molars sealed between 1993 and 1997, were assessed. The study was then based on a random sub-sample of this group, comprising 140 teeth: 86 sealed with RB (Delton) and 54 with GI (Fuji III). For a hygienist working alone, the whole procedure of applying a sealant, beginning with the cleaning of the tooth and ending with the finished sealant, took, on average, 344 (+/- 59) seconds with RB, and 599 seconds (+/- 89) with GI. This difference in time was found to be statistically significant at p < 0.01. No statistically significant difference existed in the mean time required to apply a sealant between the left (410 +/- 140 seconds) and the right (448 +/- 149 seconds) sides; however, the mandibular teeth required longer for application of the sealant than did the maxillary teeth (447 +/- 161 seconds vs. 408 +/- 125 seconds, respectively; p < 0.01). It was also found that a dentist, working with chairside assistance, took 20% less time to apply either sealant material than did the hygienist working alone. It was concluded that GI sealants, whether resealed or not, cannot be as cost-effective as RB sealants, when the expense of placement in time (and thus costs) is used as the basis of efficacy.

Surface structure, hydrophobicity, phagocytosis, and adherence to matrix proteins of Bacillus cereus cells with and without the crystalline surface protein layer.

Nonopsonic phagocytosis of Bacillus cereus by human polymorphonuclear leukocytes (PMNs) with particular attention to bacterial surface properties and structure was studied. Two reference strains (ATCC 14579(T) and ATCC 4342) and two clinical isolates (OH599 and OH600) from periodontal and endodontic infections were assessed for adherence to matrix proteins, such as type I collagen, fibronectin, laminin, and fibrinogen. One-day-old cultures of strains OH599 and OH600 were readily ingested by PMNs in the absence of opsonins, while cells from 6-day-old cultures were resistant. Both young and old cultures of the reference strains of B. cereus were resistant to PMN ingestion. Preincubation of PMNs with the phagocytosis-resistant strains of B. cereus did not affect the phagocytosis of the sensitive strain. Negatively stained cells of OH599 and OH600 studied by electron microscopy had a crystalline protein layer on the cell surface. In thin-sectioned cells of older cultures (3 to 6 days old), the S-layer was observed to peel off from the cells. No S-layer was detected on the reference strains. Extraction of cells with detergent followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a major 97-kDa protein from the strains OH599 and OH600 but only a weak 97-kDa band from the reference strain ATCC 4342. One-day-old cultures of the clinical strains (hydrophobicity, 5.9 to 6.0%) showed strong binding to type I collagen, laminin, and fibronectin. In contrast, reference strains (hydrophobicity, -1.0 to 4.2%) as well as 6-day-old cultures of clinical strains (hydrophobicity, 19.0 to 53.0%) bound in only low numbers to the proteins. Gold-labelled biotinylated fibronectin was localized on the S-layer on the cell surface as well as on fragments of S-layer peeling off the cells of a 6-day-old culture of B. cereus OH599. Lactose, fibronectin, laminin, and antibodies against the S-protein reduced binding to laminin but not to fibronectin. Heating the cells at 84 degreesC totally abolished binding to both proteins. Benzamidine, a noncompetitive serine protease inhibitor, strongly inhibited binding to fibronectin whereas binding to laminin was increased. Overall, the results indicate that changes in the surface structure, evidently involving the S-layer, during growth of the clinical strains of B. cereus cause a shift from susceptibility to PMN ingestion and strong binding to matrix and basement membrane proteins. Furthermore, it seems that binding to laminin is mediated by the S-protein while binding to fibronectin is dependent on active protease evidently attached to the S-layer.

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.

Occlusal restorative decisions based on visual inspection--calibration and comparison of different methods.

The purpose of this in vitro study was to calibrate occlusal restorative decision-making based on visual inspection (VI), and to compare it with visual inspection with magnifying (x1.25) lenses (VIM), and fibre-optic transillumination (VIF). Sixty extracted human third molars mounted in plaster were examined using VI by ten dentists three times during the calibration process. After wash-out periods, the teeth were re-examined by the same dentists using VI, VIM and VIF. The inter-examiner reproducibility for VI, expressed as Kappa (kappa) statistics (kappa +/- SD), was 0.46 +/- 0.10 before and 0.59 +/- 0.11 after the calibration process and remained at the same level after the wash-out period. Intra-examiner reproducibility was substantially higher for VI (kappa -0.68 +/- 0.15) before and after the wash-out period. There were no significant changes in restorative treatment decisions based on VIM and VIF when compared to VI. The reproducibility between the methods was good for VI vs. VIM (kappa = 0.64) and moderate for VI vs. VIF (kappa = 0.56). In contrast, the inter-examiner reproducibilities expressed as Kappa were considerably lower for VIM (kappa = 0.46 +/- 0.17) and VIF (K = 0.42 +/- 0.19). It was concluded that the inter-examiner reproducibility can be improved with a calibration process based on a simple feedback method and that inter-examiner variation, especially without calibration, may be as important a factor for restorative treatment decisions as the diagnostic method itself.

Release and activation of human neutrophil matrix metallo- and serine proteinases during phagocytosis of Fusobacterium nucleatum, Porphyromonas gingivalis and Treponema denticola.

The phagocytic ingestion of reference strains and clinical isolates of Fusobacterium nucleatum, Porphyromonas gingivalis, and Treponema denticola by polymorphonuclear leukocytes (PMNs) and the concomitant release of PMN granule proteinases were studied by specific functional and immunological assays. PMNs were incubated with the microorganisms anaerobically at 37 degrees C for indicated time periods. The suspensions and pellets were used for phagocytic ingestion assay and electron microscopic study, respectively. The supernatants were used for the measurements of the amounts and activities of the released PMN enzymes including PMN gelatinase (MMP-9), collagenase (MMP-8), serine proteases (elastase and cathepsin G), and lactate dehydrogenase (LDH). Both fluorescence microscopy and transmission electron microscopy showed that F. nucleatum, P. gingivalis and T. denticola were ingested by the PMNs in comparable numbers. However, measurements of the enzymes released from the triggered PMNs revealed major differences among the three species. High amount of elastase was released from the PMNs triggered by F. nucleatum, but not by P. gingivalis or T. denticola. The treatment of PMNs with P. gingivalis whole cells resulted in the release of gelatinase partly in the 82 kD active form, suggesting proteolytic activation of the degranulated 92 kD proMMP-9. The 82 kD active form of gelatinase was not detected upon triggering the PMNs with F. nucleatum and T. denticola. The PMN-bacteria interaction did not result in release of LDH from triggered PMNs indicating the proteinase release was not due to the PMN cell death. The results show that the susceptibilities of the 3 potentially periodontopathogenic microorganisms, F. nucleatum, P. gingivalis and T. denticola to phagocytic ingestion are not directly related to the amounts and activities of PMN enzymes released during the bacteria-PMN interactions. As PMN degranulation is considered as one of the major pathogenic mechanisms in periodontitis, the observed differences among the microorganisms may be important virulence characteristics of these species.

Microbiological findings and clinical treatment procedures in endodontic cases selected for microbiological investigation.

The relationship between bacteriological findings and clinical treatment procedures was investigated in root canal treatment cases that were selected for bacteriological investigation by general dental practitioners in Finland. The cultures were sent to the Oral Microbiological Service Laboratory at the Institute of Dentistry in Helsinki. Two groups of teeth were selected based on the type of infection present in the root canal system. The 'enteric bacteria' group consisted of 40 sequential cases where Enterococcus faecalis and/or other facultative enteric bacteria or Pseudomonas sp. were found in the samples in pure culture (35%) or together with other types of bacteria. The group 'non-enteric bacteria' consisted of 40 sequential cases where only non-enteric bacteria were found. The dentists who had sent the bacteriological samples received a questionnaire where they were asked about the treatment protocol and procedures. A total of 70 out of 80 questionnaires were returned. If the root canals had been unsealed at some point during the treatment, enteric bacteria were found more frequently than in canals with an adequate seal between the appointments. Of cases with enteric bacteria 55% had been open during the treatment, while in the group where only non-enteric bacteria were found 30% had been open. Enteric bacteria were also more frequently isolated in cases with a high number of appointments before sampling. In the enteric bacteria group 35% of the samples were taken at the 10th visit or later, while the corresponding percentage in the non-enteric group was 3%. In addition, the number of retreatment cases was significantly higher, 12 out of 34, in the enteric bacteria group than in non-enteric bacteria group, which was five out of 36. Other clinical parameters showed no differences between the two groups. The results emphasize the importance of controlled asepsis throughout the root canal treatment.

Application of computerised image analysis to monitoring endodontic therapy: reproducibility and comparison with visual assessment.

OBJECTIVE: To evaluate the intra- and interexaminer reproducibility of computerised image analysis for the assessment of periapical bone changes based on gray value ratio when compared with a visual method. METHODS: 353 radiographs obtained in a clinical endodontic study were analysed. Densitometric analyses were used to evaluate changes in bone density following endodontic treatment. The diseased area of apical periodontitis' (AP) and 'normal bone area' (AN) were defined and ratios of the gray values (AP/AN) were calculated for each radiograph. Periapical index (PAI) was used as the 'gold standard'. Correlation coefficient (r), Kappa (kappa), and t-test for matched pairs were used for the statistics. RESULTS: The method proyed to be reproducible for intra-examiner re-examinations, r ranging from 0.7 to 0.84 (P < 0.01). Kappa showed fair to good agreement for data divided into four or three categories (kappa = 0.25-0.64). Dichotomised data showed fair to moderate agreement (kappa = 0.33-0.4) when the whole process was repeated, and good to very good agreement (kappa = 0.64-0.85) for the delineation process alone. The interexaminer comparisons showed fair to moderate agreement (kappa = 0.3-0.49). Comparison with PAI showed a 61% sensitivity and 79% specificity in detecting severe lesions (corresponding PAI scores 4 and 5) and the kappa value of 0.40 showed moderate agreement. The image analysis was sensitive enough to detect healing one month after treatment in a group of teeth with substantial lesions (P < 0.05). CONCLUSIONS: The computerised image analysis system seems to be an appropriate tool to detect the periapical bone changes in dental radiographs at a group level.

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.

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 pierced 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.

Eubacterium yurii subspecies margaretiae is resistant to nonopsonic phagocytic ingestion.

We have previously shown that strains of Eubacterium yurii are hydrophobic, as compared with human polymorphonuclear leukocytes (PMNs), possibly because of a crystalline surface layer (S-layer) covering the cell envelope of this potential endo-perio pathogen. The aim of the present study was to investigate the phagocytic ingestion by PMNs of the three E. yurii subspecies, with special attention to bacterial surface structures and hydrophobicity. Type strains of subspp. margaretiae, yurii, and schtitka, together with three clinical isolates from necrotic root canals, were studied. All strains were hydrophobic when tested by a two-phase partition method. E. yurii subspp. margaretiae strains ATCC43715T, ES4C, and ES14B-8E were resistant to PMN ingestion in the absence of opsonins, whereas strains of the two other subspecies were readily ingested. The presence of a resistant strain (subsp. margaretiae ATCC43715T) did not inhibit the ingestion of a sensitive strain (subsp. schtitka ATCC43716T). Ingestion of E. yurii subsp. margaretiae strains required opsonization by normal human serum or specific antibodies. Electron microscopy revealed an S-layer in all strains and fimbria-like structures in the subspp. margaretiae and yurii strains. The antiserum prepared against the S-protein of E. yurii subsp. margaretiae ATCC43715T showed only slight cross-reactivity with other E. yurii strains and indicated the presence of strain-specific rather than species- or subspecies-specific antigens in the S-protein of E. yurii subsp. margaretiae ATCC43715T. The results suggest that the mere presence of the S-layer or fimbria-like structures cannot explain the susceptibility to ingestion by the PMNs.(ABSTRACT TRUNCATED AT 250 WORDS)

Hydrophobicities of human polymorphonuclear leukocytes and oral Bacteroides and Porphyromonas spp., Wolinella recta, and Eubacterium yurii with special reference to bacterial surface structures.

The hydrophobicities of human polymorphonuclear leukocytes (PMNLs) and Bacteroides buccae, B. oris, B. oralis, B. veroralis, B. buccalis, B. heparinolyticus, B. intermedius, B. denticola, B. loescheii, B. melaninogenicus, Porphyromonas gingivalis, P. endodontalis, Wolinella recta, and Eubacterium yurii were studied by the hexadecane method. The majority of the strains were equally or less hydrophobic than the PMNLs. Only in the case of E. yurii and the only strain of B. buccalis were all strains more hydrophobic than the PMNLs. However, some strains of B. intermedius, B. oris, B. denticola, and P. gingivalis were also more hydrophobic than the PMNLs. With the exception of B. intermedius and species with a crystalline surface protein layer (S-layer), the strains of all other species with a thick capsule were more hydrophilic than the strains with little or no extracellular polymeric material. All strains of the S-layer species were either quite hydrophilic or hydrophobic depending on the species, totally irrespective of the presence of the capsule. The results suggest that the S-layers of oral anaerobic bacteria may be important determinants of cell surface hydrophobicity.