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E Tammisalo

Publications and source records attributed to E Tammisalo.

12 recordsLinked to original sources
PubMed1999

Development of a compact computed tomographic apparatus for dental use.

OBJECTIVE: To describe a compact computed tomographic apparatus (Ortho-CT) for use in dental practice. METHODS: Ortho-CT is a cone-beam-type of CT apparatus consisting of a multifunctional maxillofacial imaging machine (Scanora, Soredex, Helsinki, Finland) in which the film is replaced with an X-ray imaging intensifier (Hamamatsu Photonics, Hamamatsu, Japan). The region of image reconstruction is a cylinder 32 mm in height and 38 mm in diameter and the voxel is a 0.136-mm cube. Scanning is at 85 kV and 10 mA with a 1 mm Cu filter. The scan time is 17 s comparable with that required for rotational panoramic radiography. A single scan collects 512 sets of projection data through 360 degrees and the image is reconstructed by a personal computer. The time required for image reconstruction is about 10 min. RESULTS: The resolution limit was about 2.0 lp mm-1 and the skin entrance dose 0.62 mGy. Excellent image quality was obtained with a tissue-equivalent skull phantom: roots, periodontal ligament space, lamina dura, and cancellous bone were clearly visualized. CONCLUSION: Ortho-CT provides three-dimensional images of excellent quality for dental use at a low entrance dose.

Humans↗
PubMed1996

An image plate system for digital intra-oral radiography.

Direct image acquisition of intra-oral images using digital, filmless, techniques has been possible only since the late 1980s, although indirect methods have been available since the late 1970s. The techniques possible so far have had a number of limitations, making them cumbersome to use. A new system, the Digora system, has recently been developed in Finland, which overcomes many of these shortcomings. The principles and uses of this system are described here.

Equipment Design↗
PubMed1992

Comprehensive oral X-ray diagnosis: Scanora multimodal radiography. A preliminary description.

Scanora (Soredex, Orion Corporation, Helsinki, Finland) is a multimodal radiography system which utilizes the principles of narrow beam radiography and spiral tomography. The system includes an integrated multifunction X-ray unit, a coordinate system for object localization and a wide selection of dental and maxillofacial imaging problems. All imaging procedures are computer controlled and executed automatically. Clinical experience and preliminary results show that the multimodal imaging system has great potential in the detection of pathological conditions of the maxillofacial region.

Humans↗
PubMed1991

Upper central incisor and canine tooth crown size in 47,XXY males.

Enamel and dentin thicknesses were measured in permanent tooth crowns of 47,XXY (Klinefelter syndrome) males. In 47,XXY males, enamel thickness in maxillary central incisors was significantly greater than that in control males or females, and dentin thickness in incisors and canines was significantly greater than that in control females, but smaller than that in normal males. These findings confirm the concept that human dental growth is affected by sex chromosomes. Amelogenesis is promoted by both X and Y chromosome genes, and sexual dimorphism in average tooth size is evidently determined by a promoting effect of the Y chromosome on dentin growth, probably through cell proliferation. This effect can also explain sex predilection for males in the numbers of supernumerary and ordinary teeth.

Amelogenesis↗
PubMed1987

47,XXX females, sex chromosomes, and tooth crown structure.

Enamel thickness of the maxillary permanent central incisors and canines in seven Finnish 47,XXX females, their first-degree male and female relatives, and control males and females from the general population were determined from radiographs. The results showed that enamel in teeth of 47,XXX females was clearly thicker than that of normal controls. On the other hand, the thickness of "dentin" (distance between mesial and distal dentinoenamel junctions) in 47,XXX females' teeth was about the same as that in normal control females, but clearly reduced as compared with that in control males. It is therefore obvious that in the triple-X chromosome complement the extra X chromosome is active in amelogenesis, whereas it has practically no influence on the growth of dentin. The calculations based on present and previous results in 45,X females and 47,XYY males indicate that the X chromosome increases metric enamel growth somewhat more effectively than the Y chromosome. Possibly, halfway states exist between active and repressed enamel genes on the X chromosome. The Y chromosome seems to promote dental growth in a holistic fashion.

Dental Enamel↗
PubMed1981

Enamel thickness of 45,X females' permanent teeth.

Enamel thicknesses in 45,X females', their male and female relatives', and population control males' and females' permanent tooth crowns were determined from radiographs. The results showed that the enamel layer in both maxillary first incisors and canines of 45,X females is definitely thinner than that of control males or females. Enamel in control males' and females' teeth was about equal in size. The distance between mesial and distal dentino-enamel junctions or the thickness of "dentin" was similar in 45,X females' and in control females' teeth, but definitely smaller than in control males' teeth. These findings show that in the presence of the second sex-chromosome in the chromosome complement, whether X or Y, there is a definite and equal increase in the amount of enamel. On the other hand, in the presence of the Y chromosome in the chromosome complement, relative to the second X chromosome, there is a definite increase in the thickness of the dentin. The results of earlier studies have indicated a direct growth-promoting effect of the sex chromosomes on tooth growth, and that the effect of X and Y chromosomes is different. The present results suggest that the influence of the X- and Y-chromosome gene(s) on amelogenesis is the same in quantitative terms but different in relation to the determination of the distance between dentino-enamel junctions; the Y chromosome is more effective than the X chromosome in that respect. It is postulated that this size-increasing effect of the Y-chromosome gene(s) might result from its profound effect on cell proliferations.

Amelogenesis↗
PubMed1975

Turku sugar studies XVIII. Incidence of dental caries in relation to 1-year consumption of xylitol chewing gum.

A longitudinal study was carried out in order to evaluate the caries incidence as affected by partial substitution of dietary sucrose (S) with xylitol (X), the effects of S- or X-containing chewing gums being compared during one year. The material comprised initially 102 young adults, predominantly dental and medical students, divided randomly into S- and X-groups. During the study 2 subjects were excluded, one due to lack of cooperation, the other not being allowed to enter the assigned S-group due to excessive caries prevalence. The subjects consumed 4.0 chewing gums per day in the S-group and 4.5 in the X-group. The frequency of sucrose intake was 4.2 times per day in the S-group, and 4.9 in the X-group. The caries incidence, assessed independently by clinical and radiographical means, expressed as the mean increment of decayed, missed and filled tooth surfaces, was 2.92 in the S-group, and --1.04 in the X-group. The corresponding values, when considering additionally the secondary caries reverals, were 3.76 in the S-group, and 0.33 in the X-group. The caries incidence was also expressed in combined quantitative and qualitative terms by considering in addition to the above parameters, also the changes in lesion size. The caries activity index thus calculated was 4.96 in the S-group, and 0.88 in the X-group. The results show a profound difference in the caries increment rate between the two experimental groups. The findings clearly indicate a therapeutic, caries inhibitory effect of xylitol.

Adult↗
PubMedDate not supplied

Enamel thickness in 47,XYY males' permanent teeth.

Enamel thickness of the maxillary permanent central incisors and canines in 14 47,XYY males, their male and female relatives and population-control males and females were determined from radiographs. The results indicated, although not fully unambiguously, that the thickness of enamel and that of 'dentin' (distance between mesial and distal dentino-enamel junctions) are increased in the teeth of 47,XYY males compared with normal controls. Earlier results have indicated a direct growth-promoting effect of the Y chromosome on tooth growth by influencing both enamel formation and, possibly through cell proliferations, growth of dentin. The present results can be considered additional evidence for the presence of the factors within the Y chromosome controlling different growth processes. Tooth size measurements in two males with deletions of the parts of the y chromosome suggested that there may be a specific growth-promoting gene(s) in the non-fluorescent part of the long arm. It is suggested that the way of influence of the Y chromosome on the amelogenesis is regulatory, and that the difference in tooth size between males and females is explained by a differential growth-promoting effect of the Y chromosome compared to the X chromosome.

Chromosome Deletion↗
PubMedDate not supplied

Orthopantomography.

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Humans↗