Search results for "odontometry"
showing 10 items of 21 documents
Evolution of mammal tooth patterns: new insights from a developmental prediction model.
2009
14 pages.; International audience; The study of mammalian evolution is often based on insights into the evolution of teeth. Developmental studies may attempt to address the mechanisms that guide evolutionary changes. One example is the new developmental model proposed by Kavanagh et al. (2007), which provides a high-level testable model to predict mammalian tooth evolution. It is constructed on an inhibitory cascade model based on a dynamic balance of activators and inhibitors, regulating differences in molar size along the lower dental row. Nevertheless, molar sizes in some mammals differ from this inhibitory cascade model, in particular in voles. The aim of this study is to point out arvi…
Anthropoid versus strepsirhine status of the African Eocene primates Algeripithecus and Azibius: craniodental evidence.
2009
Recent fossil discoveries have demonstrated that Africa and Asia were epicentres for the origin and/or early diversification of the major living primate lineages, including both anthropoids (monkeys, apes and humans) and crown strepsirhine primates (lemurs, lorises and galagos). Competing hypotheses favouring either an African or Asian origin for anthropoids rank among the most hotly contested issues in paleoprimatology. The Afrocentric model for anthropoid origins rests heavily on the >45 Myr old fossil Algeripithecus minutus from Algeria, which is widely acknowledged to be one of the oldest known anthropoids. However, the phylogenetic position of Algeripithecus with respect to other p…
Mandibular incisor extraction: indications and long-term evaluation
1996
The extraction of a lower incisor constitutes a therapeutic alternative limited to certain occlusal situations, i.e. supernumerary incisors, tooth size anomalies (peg-shaped upper laterals), ectopic eruption and anterior crossbites. The effect of the extraction of a single incisor on the out of retention alignment of lower anterior teeth was studied in 26 treated cases. Initial (T1), final (T2) and 5-8 years out of retention (T3) dental casts were measured. Mean crowding at the start of treatment (T1 = 3.86 mm) relapsed out of retention (T3 = 1.49 mm), with a net mean improvement of 2.37 mm. Little's irregularity index at the start of treatment (T1 = 6.44) relapsed out of retention (T3 = 2.…
Do Bolton’s ratios apply to a Spanish population?
2004
Introduction: Previous studies have shown that populations differ with respect to interarch tooth-size relationships, and differences in tooth sizes are not systematic. The aims of this study were to determine the Bolton ratios in Spanish subjects. Methods: We used a digital method and measured the casts to the nearest 0.05 mm. The sample consisted of 100 pairs of dental casts of Spanish subjects. The Kolmogorov-Smirnov test, t test, and 95% confidence intervals were used. Results: Anterior tooth-width ratios were 78.31% ± 2.59% for women and 78.34% ± 2.16% for men (P = .955). Total tooth-width ratios were 91.91% ± 2.04% for women and 92.10% ± 1.73% for men (P = .668). No significant differ…
Determination of Bolton tooth-size ratios by digitization, and comparison with the traditional method.
2005
The Bolton Index is one of the most useful calculations for precise orthodontic diagnosis as it shows if there is a correct ratio between dental proportions. However, at times, this calculation is not applied because it is a long and time-consuming procedure compared with digital methods. A new digital method for measuring tooth sizes and for calculating the Anterior (ABI) and the Overall (OBI) Bolton Index was tested on 100 sets of study dental casts of the permanent dentition in a Spanish sample and compared with the traditional method. The reproducibility of this digital method versus the traditional one was analysed to determine intra- and inter-examiner measurement errors by calculatin…
Prediction of arch length based on intercanine width.
2008
Arch length (AL), intercanine width (ICW), and intermolar width (IMW) are essential for diagnosis and treatment planning and are closely related factors in orthodontics. The aim of the present study was to determine correlations between these measurements and to predict some of these measurements based on others. The dental casts of 197 Spanish patients (119 females and 78 males) with a mean age of 18 years (11-26 years) in the permanent dentition attending the Orthodontic Department of the University of Valencia, Spain, were selected. ICW, IMW, and AL on each dental cast were measured using a previously tested digital method. Correlation between variables was determined using Pearson's cor…
Tooth size changes with age in a Spanish population: Percentile tables
2010
Objectives: The aims of this work were: firstly, to draw up tables of percentile tooth sizes similar to those of Sanin and Savara for three age groups of a Spanish population; secondly, to describe changes in tooth size between those groups over time, as well as observing any sexual dimorphism and, finally, to compare both the Spanish and Sanin and Savara's American population samples. Material and methods: The sample included 359 patients and was divided into three age groups: adolescents, young adults and adults, of both genders. After dental cast digitalization, mesiodistal tooth-size was measured on each dental cast using a digital method. Dental size tables organized by percentiles for…
Smile esthetics from odontology students' perspectives
2013
ABSTRACT Objectives: To analyze the perception of smile esthetics and its alterations in dental degree students; to determine whether there are differences in that perception among students in different study years on those courses and between genders; and to determine if the circumstance of having received prior orthodontic treatment could influence that perception. Material and Methods: Students (n = 192) in different study years of the dental degree course at the University of Valencia, Spain, analyzed two photographs of a patient in which, by means of computer software, midline diastema, upper and lower midlines, crown length of the maxillary right central incisor, occlusal cant, and “g…
Evolution of dental arches characteristics in two age groups
2005
Introducción: Se comparan las características dimensionales de las arcadas dentarias entre dos grupos de edades diferentes, adolescentes y adultos jóvenes, para analizar las variaciones asociadas a la edad, sexo y a la influencia del tratamiento ortodóncico. Material y método: Se utilizaron dos muestras: 88 pares de modelos de escayola de adolescentes (edad media 14,05 años) y 65 de adultos (edad media 22,15 años). Se usó un método digital para la medición de los diámetros mesiodistales de los dientes, distancias intercaninas e intermolares, longitudes de las arcadas y se obtuvo el apiñamiento dentario inferior. Para el análisis estadístico se agruparon las muestras de cada grupo de edad po…
Prediction of the mesiodistal size of unerupted canines and premolars for a group of Romanian children: a comparative study
2013
Objectives The aim of the present study was to develop an optimization method of multiple linear regression equation (MLRE), using a genetic algorithm to determine a set of coefficients that minimize the prediction error for the sum of permanent premolars and canine dimensions in a group of young people from a central area of Romania represented by a city called Sibiu. Material and Methods To test the proposed method, we used a multiple linear regression equation derived from the estimation method proposed by Mojers, to which we adjusted regression coefficients using the Breeder genetic algorithm. A total of 92 children were selected with complete permanent teeth with no clinically visible …