Intra- and Inter-Examiner Reliability and Inter-Method Comparison in Physical Anthropometry and Photogrammetry

Objective: Orthodontic treatment can often effect changes in the facial complex. In order to assess what those changes are, precise and reliable methods for measuring facial structures need to be used. While the techniques used for measuring have become increasingly more sophisticated they have also become more expensive and cumbersome for daily use. This study investigated the reliability of two methods, physical anthropometry and photogrammetry, that were inexpensive and relatively easy to set up. Materials and Methods: Ten examiners measured a sample comprised of 20 dental students (10 male, 10 female) twice over three weeks. Eighteen measurements were acquired directly using a digital caliper. The 18 measurements were comprised of 20 facial landmarks previously defined by Farkas (1981). In addition, standardized facial photographs were made of the 20 participants, and the examiners were asked to identify the same points. The images were then calibrated and the same facial measurements computed. The intra-class correlation coefficient was used to determine the intra- and inter-examiner reliabilities. The Bland-Altman method was used to compare the two methods. Results: Anthropometric intra-examiner reliability was very high for all measurements, while inter-examiner reliability exhibited a wide range of values, Overall the reliabilities were higher for easily identifiable landmarks, such as landmarks around the mouth, eyes, the nose, while bony landmarks covered by soft-tissue produced less reliable measurements. With few exceptions, photogrammetric reliability was high for both inter- and intra-examiner reliabilities. The least reliable measurement was the interlabial gap probably due to placement error of the points which was compounded by the small distances measured. The Altman-Bland plots showed large variability around the average difference. Conclusions: The study found that examiners demonstrate high intra-rater reliability regardless of which method was used. Inter-examiner reliability showed larger variability dependent on the method. When using a caliper the examiner was not as consistent as on a photograph when selecting the facial landmarks. While both methods allow for accurate intra-examiner measurements, this study found that the photogrammetric method had greater inter-examiner agreement. However, large variability was found when comparing the two methods

Fundamental Investigations on the Unit Groups of Commutative Group Algebras in Bulgaria

In this paper we give the first investigations and also some basic results on the unit groups of commutative group algebras in Bulgaria. These investigations continue some classical results. Namely, it is supposed that the cardinality of the starting group is arbitrary

Intra- and inter-examiner Reliability of Direct Facial Soft Tissue Measurements Using Digital Calipers

Background: The objective of this study is to determine if facial soft tissue measurements using digital calipers can be reliably taken by the same examiner and by a large group of examiners. Materials and Methods: Ten examiners performed a set of 18 in-clinic measurements on 10 female and 10 male dental students using a digital caliper twice over a 3-week period. The intra-class correlation coefficient and the Shrout-Fleiss method were used for the statistical analysis. Results: Anthropometric intra-examiner reliability was high for all measurements (none fell below R = 0.934). However, inter-examiner reliability exhibited a wide range of values, some reliable (nasal width at widest nostrils [R = 0.922] and subnasale to upper lip [R = 0.926]), and others unreliable [base of nose (R = 0.590), mouth height (R = 0.585), and soft tissue B point to gnathion (R = 0.623)]. Conclusions: Soft tissue measurements of clearly identifiable points measured by the same examiner produced highly consistent, accurate and reliable measurements. Soft tissue points with poor definition resulted in average-to-poor reliabilities measurements

A contibution to the knowledge of the trophic spectrum of three lacertid lizards from Bulgaria

A study on the trophic spectrum of three species of lacertid lizards (Lacerta agilis, Lacerta trilineata and Podarcis muralis) was carried out, based on 20 specimens collected in the period 1967-1973 in various localities in Bulgaria. The analyzed data showed that the insects (Insecta) are the most numerous and the most frequently met among the alimentary components of the total amount of food of the studied stomachs (except for Lacerta agilis, where spiders are slightly predominating). The non-insect components consisted spiders and isopods. The largest niche breadth was recorded in Lacerta trilineata (8.25), followed by Podarcis muralis (5.20) and Lacerta agilis (3.44). The niche overlap between the three species (pair-wise comparison) showed medium values and in our opinion there should not be any serious competition for food resources at the places withsympatric distribution

Isomorphism of Commutative Group Algebras of Finite Abelian Groups

Let a commutative ring R be a direct product of indecomposable rings with identity and let G be a finite abelian p-group. In the present paper we give a complete system of invariants of the group algebra RG of G over R when p is an invertible element in R. These investigations extend some classical results of Berman (1953 and 1958), Sehgal (1970) and Karpilovsky (1984) as well as a result of Mollov (1986)