Biomedical subjects
Publications and source records attributed to S Järvinen.
Orthodontic treatment need indexes are used extensively in Northern Europe, especially in selecting patients for treatment in public orthodontic health services and in determining the level of third party copayment. This article describes certain treatment need indexes and their uses in everyday practice. The reliability and validity of indexes are discussed.
We report the case of a patient who, 9 months after initiation of enalapril and hydrochlorothiazide combination treatment for hypertension, developed angio-oedema with near fatal outcome. Our patient was successfully intubated using a flexible bronchofiberoscope. This case demonstrates that patients given an angiotensin-converting enzyme (ACE) inhibitor may develop serious facial and laryngeal swelling even several months after the initiation of treatment. The occurrence of even mild swelling should lead to prompt cessation of the drug. Patients with incipient ACE inhibitor-related angio-oedema should, without any delay, be referred to hospital for emergency treatment.
The mathematical model (Järvinen) for measuring the sagittal difference between the maxillary and mandibular apical bases has been clinically tested. The material for this study consisted of 30 lateral skull radiographs of orthodontically untreated children (aged seven to 15 years) with different types of skeletal and/or dento-alveolar malocclusions. A comparison of the model with two conventional and two more developed methods to measure the sagittal apical base difference showed that the correlation between the new and the older methods increased as the errors of the older methods were eliminated. The results seemed to indicate that sagittal malocclusions could be accurately diagnosed by means of the model.
The hypothesis that the relationship between the ANB angle and the Wits appraisal can be expressed by measuring the individual variations in their reference systems and by constructing a model of regression between them and a few parameters describing the reference systems was tested with material consisting of 30 lateral cephalometric radiographs of untreated orthodontic patients with different types of skeletal and/or dentoalveolar malocclusions. The results indicated that approximately 93% of the variation of the Wits appraisal could be explained by the variation of the ANB, NSL/OL, and SNA angles. The study also showed that the results given by different measurements with different reference systems, such as the ANB angle and the Wits appraisal, cannot be directly compared. To obtain comparable interpretations, one should correct the results of both measurements in relation to the variations in their reference systems.
Certain factors causing variation of linear radiographic cephalometric measurements were evaluated using the regression analysis. The material of the study consisted of data from three earlier investigations and included 73 measurements of four separate samples of children and young adults. Approximately 75% of the variation of the variation coefficient (V) could be attributed to the variation in the length of the measurements (means) and thus mainly to the mathematic properties of V. Thus, differences in the relative variation did not always indicate differences in the absolute variation (SD). Two factors were extracted that had an increasing effect upon the variability--the location of the reference points on an osseous contour and the location of the reference points (one or both) in the mandible. The great variability of the reference points located on osseous contours was probably caused by local changes in bone configurations, and the great variability of the measurements involving the mandible probably indicated some specific growth changes in the size, form, and rotation movements of this bone. In clinical use such reference points that include relevant information only and that could be fixed by consistent features of the local morphology should be preferred.
The need for orthodontic treatment was assessed in a sample of 29 children by using four treatment-need indices (ISMHB by the Swedish Medical Health Board, HMAR by Salzmann, INOT by Ingervall & Rönnerman, and TPI by Grainger). Furthermore, the need for treatment was evaluated clinically according to the criteria of Järvinen. When scoring the cases, and when selecting the cases with the highest scores, the study showed a marked variation between the indices, and indicated that the different methods selected different groups of children for treatment. Indirectly, the conclusion could be drawn that there were differences in the validity of the indices, even though it was not possible to evaluate the degree of validity on the basis of the knowledge we have today about the disadvantages and consequences of malocclusions.
The normal values of the angular radiographic cephalometric measurements in the Bergen analysis, the so called orthognathic combinations, were compared with the associations between these measurements obtained from two population samples. The original sample of the study consisted of 55 untreated orthodontic patients aged 7-14 years and with Angle's Class I malocclusion. Additional data were obtained from Solow's study on young male adults. The comparison indicated differences between the Bergen acceptable combinations and the population estimates. The Bergen norms seemed to be constructed partly on the basis of solely topographical correlations. Therefore, it can be claimed that Bergen cephalometric norms are more artificial than biological, because of which the clinical use of the Bergen analysis requires special caution.
Explore the source record for details and available documents.
If the ANB angle is used in cephalometric analyses, its individual nature should be recognized. A method to interpret the measured values of the ANB angle has been recently presented by Hussels and Nanda. This article introduces another method to evaluate the appropriateness of the measured values. A regression analysis was applied to explain the individual variation of the ANB angle in a sample of 55 untreated orthodontic patients, aged 7 to 14 years, with Class I (Angle) malocclusion. Approximately 63% of the variation of the ANB angle could be explained by the variation of the SNA and NSL/ML angles. The regression produced a list of floating norms of the ANB angle for different facial types. The floating norms can help to interpret the individual normal variation of the ANB angle.
Explore the source record for details and available documents.
The variation of the ANB angle was studied in a sample which consisted of 138 orthodontically untreated children 7 to 15 years of age with Class I, Class II, or Class III (Angle) malocclusion. A regression analysis was used in order to describe the proportion of the distorting variation caused by some usual changes in the cranial and facial skeleton. The results revealed that a part of the variation of the ANB angle could be attributed to factors other than the actual apical base difference, among these factors being the rotation of the S-N plane, the relative length of the S-N plane, and the rotation of the jaws. Because the ANB angle can vary without any marked abnormalities in the sagittal jaw relationship, the use of the so-called normal limits for the ANB angle is not justified. It would be better to replace the ANB angle with a more accurate indicator.
The relation of the age-specific mean DMFT and mean DMFS to the age-specific proportion of children with DMF teeth has been studied using the original data of Knutson and data of a recent Finnish material. When studying the relationship between the mean DMFT (x) and the proportion of children with DMF teeth (y), three models of regression were compared. For low caries populations, a specific correction exponential curve y = 1-abx seemed to fit caries data somewhat better than the other models. The relationship between the mean DMFS (x) and the proportion of children with DMF teeth (y) could be expressed by a curvilinear model y = e[b(lnx) + a]; this applied to low caries populations (y approximately less than 0.7) as well, but the unexplained residual variation was about 6%.
In cephalometric radiography, two angles have been commonly used, the saddle angle (NSAr) and the SNA angle. The former has been regarded as the cranial base angle, the latter as an indicator of the antero-posterior relation of the maxilla to the cranial base. In this study, a sample of 138 lateral skull radiographs of untreated orthodontics patients aged 7-15 years and analysed. The sample consisted of Angle's Class I, Class II, and Class III malocclusion cases. Means and standard deviations of the NSAr and SNA angles and the S-N and S-Ar lines for different malocclusion groups were estimated, and for each malocclusion group, the model of linear regression (y = bx + a) between the SNA and NSAr angles was computed. The mean of the NSAr angle was significantly larger in the Class II malocclusion group than in the Class III malocclusion group (p less than 0.05). The computed regressions indicated that about 14-40 per cent of the variation of the SNA angle in different malocclusion groups and about 24 per cent in the whole sample could be explained by the variation of the NSAr angle. Because at least a part of the correlation between the NSAr and SNA angles had a topographical causation, the main cause of this topographical correlation probably being the rotation of the S-N plane, the SNA angle was regarded as an unreliable indicator, the use of which can lead to considerable errors.
The relationship between the age-specific mean number of DMF teeth and the age-specific mean number of DMF surfaces in the population has been studied using the original data of Knutson and epidemiologic data from five Finnish materials, including data of 4718 subjects examined. Two models of regression between the variables were evaluated statistically by making a comparison between a linear and a curvilinear model of regression. For Knutson's original data, both models were suitable, apart from one data set with a relatively high caries prevalence, for which the association between the variables could be better expressed by the linear model. Concerning the recent Finnish materials, the difference in accuracy between the models seemed to be related to the range of the measurements; the larger the range of the measured caries prevalences, including low and high prevalence rates, the more proponderant the curvilinear model. For very low caries populations as well, the curvilinear model, a correction exponential curve, seemed to fit caries data somewhat better than the straight line.
Explore the source record for details and available documents.
The correlation between the NSAr and the SNA angles was studied in two separate samples. The first sample consisted of twenty young adults with excellent Class I (Angle) occlusion and proportionate facial skeleton, and the second sample consisted of sixty-one children with Class II, Division 1 (Angle) malocclusion. In the excellent-occlusion group, the correlation between the angles was remarkably higher (-0.94) than it was in the malocclusion group (-0.57). In both groups, in only a small number of cases were the extents of the angles close to the intersection of the calculated mean values. In orthodontic diagnosis, treating the values of the NSAr and the SNA angles separately can be extremely misleading, just as the use of the sella-nasion plane as a sole reference plane can lead to diagnostic errors. Thus, the SNA angle should be used with special caution, and a differing reference plane such as, for example, the Frankfort plane, should be preferred.
Explore the source record for details and available documents.
Explore the source record for details and available documents.