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.

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.

Radiographic detectability of periodontal diseases. A comparison of perapical radiography with detailed zonography.

Objective: To compare the diagnostic accuracy of conventional periapical radiography with detailed zonography using the Scanora system for the detection of periodontal disease.

Methods: We selected for comparison 311 periodontal sites in 165 patients. Five observers independently assessed the periapical radiographs and detailed zonograms for marginal widening of periodontal ligament space, crestal erosion, vertical bone loss, furcation involvement and calculus.

A comparison of detailed zonography with periapical radiography for the detection of periapical lesions.

The diagnostic accuracy of detailed zonography using the Scanora multimodal X-ray system was compared with that of periapical radiography. The study was based on the detection of periapical bone lesions at 259 dental sites distributed evenly throughout the dentitions of 164 patients. Each site was examined by periapical radiography and zonography, in parallel.

Comparison of periapical and detailed narrow-beam radiography for diagnosis of periodontal pathology.

The diagnostic performance of the detailed narrow-beam (DNB) technique of the Scanora multimodal X-ray system was compared with periapical radiography for detecting periodontal pathology. In total, 253 sites in 133 patients were examined. Receiver operating characteristics (ROC) of both imaging modalities were analyzed in relation to the ratings of five observers for the whole dentition, three dental regions and five types of periodontal lesion.

Comparison of periapical and detailed narrow-beam radiography for diagnosis of periapical bone lesions.

The diagnostic performance of the detailed narrow-beam (DNB) technique of the Scanora multimodal radiography system was compared for periapical radiography for the detection of periapical bone lesions at 262 dental sites in 144 patients. Receiver operating characteristics (ROC) of both imaging modalities were analysed in relation to the ratings of five observers for the whole dentition, three dental regions, and two types of periapical lesions. ROC analysis demonstrated no overall or regional significant differences in the diagnostic performance of the two imaging modalities.

Stereographic assessment of mandibular canal in relation to the roots of impacted lower third molar using multiprojection narrow beam radiography.

The position of the mandibular canal in relation to the superimposed roots of 173 impacted lower 3rd molars was evaluated radiologically. A multiprojection narrow beam radiography (MNBR) technique recently developed for oral radiography was applied in this study. This method enables stereoscopic examination of the area of interest.

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.

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.

Multimodal radiography: a new imaging technique and system for oral diagnosis.

The multimodal radiography system is based on the combined use of narrow-beam radiography and spiral tomography in one set of equipment. The essentials of a system are a multifunction unit, preprogrammed imaging procedures for various dentomaxillofacial objects and a co-ordinate system for object location. Four years of clinical experience have shown that multimodal radiography is effective for depicting dentomaxillofacial structures for diagnostic purposes.

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.

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.

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.

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.