The 3DX multi image micro-CT device in clinical dental practice.

OBJECTIVES: To evaluate the usefulness of 3DX multi-image micro-CT device in clinical dental practice. METHODS: Images of 198 examinations performed with a 3DX device during a 6 month period in a private dental practice were evaluated retrospectively for the benefit of additional information compared with panoramic or intraoral radiographs. RESULTS: The main indication for the use of 3DX micro-CT was planning of dental implant placement in 49% of the examinations. Diagnosis or exclusion of dental infection or peri-implantitis represented 28% of the examinations and tooth, root or foreign body localization represented 13%. Temporomandibular joint (TMJ) imaging and cyst or tumour diagnosis represented 7.5% and 2.5% of the examinations, respectively. In implant planning and tooth, root or foreign body localization examinations, the required information was obtained in every case except three implant planning examinations, in which the exact measurements were hampered by artefacts caused by root fillings and retrograde fillings or metal posts. When compared with conventional radiography, additional radiographic information was obtained in 51% of the micro-CT examinations performed to confirm or exclude dental infection or peri-implantitis. Micro-CT also showed the bone structure of TMJs precisely. CONCLUSIONS: The 3DX micro-CT device visualizes bony anatomical structures precisely, which makes it a reliable tool for, for example, planning of implant treatment. The device is highly suitable for diagnosing dental infections. Dental restorations may cause disturbing artefacts and in 4.5% of the examinations the small imaging area resulted in re-examination.

Cross-sectional tomograms obtained with four panoramic radiographic units in the assessment of implant site measurements.

OBJECTIVES: The aim of this study was to evaluate the ability of four panoramic X-ray units to produce cross-sectional images and to assess the effect of interexaminer and intraexaminer variations on the results. METHODS: Cross-sectional tomograms of a human cadaver mandible were taken from two edentulous and one dentate area using four different X-ray units: OP-100 Ortho Trans (Instrumentarium Imaging Co, Tuusula, Finland), Proscan (Planmeca Co, Helsinki, Finland), Cranex-Tome and Scanora (Soredex, Orion Co, Espoo, Finland). Four different linear distances were measured from each radiograph. The mandible was then cut into 4 mm thick slices at three marked places. These slices were microradiographed and used as the gold standard for measurements made from each cross-sectional tomogram. RESULTS: Of all measurements only the thickness of the mandible in the radiographs taken with the OP-100 differed significantly (P < 0.021) from the gold standard. In the interexaminer variation, the agreement was 85% and Kappa index 0.68. In the intraexaminer reproducibility, the agreement was 76.7% and Kappa indices 0.52 and 0.50. CONCLUSIONS: The X-ray units studied were found to be similar in terms of image performance and the produced images were acceptable for dental implant placement planning. Interexaminer and intraexaminer variations can be large and the main source of error can be the interpreter him or herself.

Isolation of toxigenic Nocardiopsis strains from indoor environments and description of two new Nocardiopsis Species, N. exhalans sp. nov. and N. umidischolae sp. nov.

Nocardiopsis strains were isolated from water-damaged indoor environments. Two strains (N. alba subsp. alba 704a and a strain representing a novel species, ES10.1) as well as strains of N. prasina, N. lucentensis, and N. tropica produced methanol-soluble toxins that paralyzed the motility of boar spermatozoa at <30 microg of crude extract (dry weight) x ml(-1). N. prasina, N. lucentensis, N. tropica, and strain ES10.1 caused cessation of motility by dissipating the mitochondrial membrane potential, Deltapsi, of the boar spermatozoa. Indoor strain 704a produced a substance that destroyed cell membrane barrier function and depleted the sperm cells of ATP. Indoor strain 64/93 was antagonistic towards Corynebacterium renale. Two indoor Nocardiopsis strains were xerotolerant, and all five utilized a wide range of substrates. This combined with the production of toxic substances suggests good survival and potential hazard to human health in water-damaged indoor environments. Two new species, Nocardiopsis exhalans sp. nov. (ES10.1T) and Nocardiopsis umidischolae sp. nov. (66/93T), are proposed based on morphology, chemotaxonomic and physiological characters, phylogenetic analysis, and DNA-DNA reassociations.

Radiographic findings in the teeth and jaws of 14- to 17-year-old Estonian schoolchildren in Tartu and Tallinn.

Panoramic radiographs were taken of 392 Estonian schoolchildren (33% boys and 67% girls) aged 14-17 years, 197 in Tartu and 195 in Tallinn. The mean number of permanent teeth was 31.5. In 14% of the children one to four teeth (excluding wisdom teeth) were missing. The frequencies of missing wisdom teeth and supernumerary teeth agreed with those in the literature, being 17% and 3%, respectively. The mean number of radiographically detected carious teeth was 1.9 in Tartu and 3.3 in Tallinn. Secondary caries was common, being found radiographically in half of the schoolchildren. Endodontic treatment had been given to 13% of the subjects in Tartu and to 46% in Tallinn, the success rates being 47% and 44%, respectively. The percentage of radiographic signs in the mandibular condyles of girls (5%) was greater than that of the boys (1%). Changes in the maxillary sinuses were found in 16% of the children. Eight odontogenic cysts, one cyst of the incisal canal, and one solitary bone cyst were found. Tumors included two odontomas, two cemento-ossifying lesions, and one osteoma in the maxillary sinus. The health status of the jaws of the Estonian schoolchildren was considered to be fairly good.

Dental health in 14- to 17-year-old Estonian schoolchildren in Tartu and Tallinn.

The dental health of 392 Estonian schoolchildren aged 14-17 years (197 in Tartu and 195 in Tallinn) was studied. In Tartu only 1 child had lost teeth because of caries, as against 30 in Tallinn. Clinically caries-free dentitions were found in 15% of the children in Tartu and in 3% in Tallinn. The mean DMFT value was 3.7 in Tartu and 7.0 in Tallinn, being higher among girls in both cities. The mean DT value was 1.0 in Tartu and 2.6 in Tallinn. All subjects examined had a gingival bleeding index (GBI) higher than zero. The mean GBI was 20% in Tartu and 18% in Tallinn.

A follow-up study of radiographic findings in the mandibular condyles of orthodontically treated patients and associations with TMD.

Our earlier studies have shown that some radiographic structural findings in the mandibular condyles are more common in orthodontically treated populations than in normal populations. To test the hypothesis that these findings are stable, we studied condylar findings in panoramic radiographs longitudinally in 39 subjects and in 39 sex- and age-matched controls. The subjects had condylar findings at the end of orthodontic treatment at about 15 years of age; no such findings were seen in the controls. The subjects and controls were re-examined radiographically about 12 years after the posttreatment radiographic examination. We also tested the hypothesis that radiographic condylar findings are associated with temporomandibular disorders (TMD). No statistically significant differences were found between subjects and controls in terms of reported subjective TMD symptoms. Clinically, the subjects had temporomandibular joint (TMJ) crepitation significantly more frequently (27%) than controls (8%) (p < 0.05). Crepitation correlated with some reported symptoms and clinical signs, suggesting that osteoarthrosis might have been an important etiological factor for TMD in the present subjects. At the follow-up examination, radiographic condylar findings were seen in 25 subjects and in four controls (p < 0.001). The condylar findings varied greatly between the time of orthodontic treatment and follow-up in the subjects. The findings had become more severe in 49% of the subjects, more often in females than in males (p < 0.05), whereas in 28% of the subjects the condylar findings had disappeared. Although the radiographic findings after orthodontic treatment fluctuated with age, in most adolescents with changes in their condyles, these findings remained constant or became more severe.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiographic structural findings in the mandibular condyles of young individuals receiving orthodontic treatment.

Radiographic findings in mandibular condyles were studied from the pre- and post-treatment panoramic radiographs of 625 orthodontic patients. The subjects' mean age was 11 years at the start and 14 years at the end of active orthodontic treatment. Radiographic condylar findings were seen in 14 (2%) subjects before treatment and in 54 subjects (9%) after treatment (p < 0.001). In age-related controls (n = 783) condylar findings were seen in 3% (p < 0.001). The condylar finding was 'flattening only' in half of the patients and in one-third of the controls with condylar findings. Activator treatment was associated with condylar findings (p < 0.05). Condylar findings increased with age in the orthodontically treated subjects (p < 0.05) but not in the unselected population controls. This may mean that condyles become more sensitive with age in children. Increase with age may be partly due to the radiographic interpretation, since minor condylar findings are difficult to observe in young children, and partly due to differences in treatment modalities and the duration of treatment.

Radiographic characteristics in mandibular condyles of orthodontic patients before treatment.

Pretreatment panoramic radiographs and patient files of 625 orthodontic patients (269 males and 356 females), aged 4-15.9 years (mean 11.0, SD 1.7) were evaluated with special emphasis on the mandibular condyles and malocclusions. Radiographic characteristics in the mandibular condyle were seen in 14 children (2.2 per cent), comprising six boys (2.2 per cent) and eight girls (2.3 per cent). There were no statistically significant differences between orthodontic patients before treatment and normal population controls (n = 410,229 males and 181 females, mean age 11.4 years, SD 1.8). No statistically significant difference in the frequency of condylar characteristics was found between younger (under 12) and older (over 12) children. Angle Class II molar relationship was the only type of morphological malocclusion associated (P < 0.05) with condylar characteristics. The means of several cephalometric measurements in the children with condylar characteristics were close to those of children with harmonious skeletal relationships.

Radiological variations in mandibular condyles of Finnish students, one group orthodontically treated and the other not.

Panoramatomograms of 968 students (355 males and 613 females) aged between 19 and 25 years were evaluated with special emphasis on the mandibular condyles. Two-hundred-and-thirty-five students (24.3 per cent) had been treated orthodontically. Radiographic variations in the condyles were significantly more common in the orthodontically treated group as a whole and in males (n = 71, P < 0.001), but not in females (n = 164). No age correlation in the frequency of condylar variations was found in either group. In terms of individual severe variation, flattening of the articular surface (P < 0.001) and subcortical sclerosis (P < 0.01) were more common in the orthodontically treated students. In the untreated subjects (284 males and 449 females), females had more variations (9.3 per cent) in their condyles than males (3.7 per cent P < 0.001). In the orthodontically treated students the percentages with condylar variations were 21.1 per cent in males and 16.5 per cent in females (N.S.).

A panoramatomographic study of the teeth and jaws of Finnish university students.

A random sample of panoramic radiographs was taken of 1027 (386 male and 641 female) university students. All the students were born between 1965 and 1971. The following were examined: caries, apical radiolucencies, endodontically treated teeth, marginal and vertical bone loss, third molars, supernumerary, missing, and persisting teeth, bone structure, condyles, maxillary sinuses and soft tissue calcifications. In the inter- (of two examiners) and intra-examiner variation Kappa indices varied between 0.15 and 1.00, and agreement percentages from 52, to 100. Kappa index was poor (0.15) in evaluation of the bone structure. The mean DMFT index for the students was 8.4. A sound dentition was found in 6.6%, and 48.4% of the students were free of caries. The mean number of carious lesions was 1.1. There were 50 retained roots (49 from primary teeth). 76.6% of the students had one or more unerupted wisdom teeth and 22.7% had radiologic changes typical of pericoronitis in the region of the mandibular third molars. 16.2% of the students had at least one missing wisdom tooth. Bone structure was normal in 92.4% of the students, idiopathic osteosclerosis being the most common divergence (3.5%). Arthrotic changes in the condyles were found in 9% of the students. In eight cases there was erosion of the condyles, which was diagnosed as arthritis. Styloid ligament calcifications were found in 21.5% of the students. In the maxillary sinuses, male students exhibited changes 1.7 times more often than female students (26.3% in males and 15.1% in females).