Use of self-organizing maps for analyzing the behavior of canines displaced towards midline under interceptive treatment.

BACKGROUND: Displaced maxillary permanent canine is one of the more frequent findings in canine eruption process and it's easy to be outlined and early diagnosed by means of x-ray images. Late diagnosis frequently needs surgery to rescue the impacted permanent canine. In many cases, interceptive treatment to redirect canine eruption is needed. However, some patients treated by interceptive means end up requiring fenestration to orthodontically guide the canine to its normal occlusal position. It would be interesting, therefore, to discover the dental characteristics of patients who will need additional surgical treatment to interceptive treatment. MATERIAL AND METHODS: To study the dental characteristics associated with canine impaction, conventional statistics have traditionally been used. This approach, although serving to illustrate many features of this problem, has not provided a satisfactory response or not provided an overall idea of the characteristics of these types of patients, each one of them with their own particular set of variables. Faced with this situation, and in order to analyze the problem of impaction despite interceptive treatment, we have used an alternative method for representing the variables that have an influence on this syndrome. This method is known as Self-Organizing Maps (SOM), a method used for analyzing problems with multiple variables. RESULTS: We analyzed 78 patients with a PMC angulation higher than 100 . All of them were subject to interceptive treatment and in 21 cases it was necessary to undertake the above-mentioned fenestration to achieve the final eruption of the canine. CONCLUSIONS: In this study, we describe the process of debugging variables and selecting the appropriate number of cells in SOM so as to adequately visualize the problem posed and the dental characteristics of patients with regard to a greater or lesser probability of the need for fenestration.

Orthodontic camouflage versus orthognathic surgery for class III deformity: comparative cephalometric analysis.

The objective of this study was to compare different cephalometric variables in adult patients with class III malocclusions before and after treatment, in order to determine which variables are indicative of orthodontic camouflage or orthognathic surgery. The cases of 156 adult patients were assessed: 77 treated with orthodontic camouflage and 79 treated with orthodontics and orthognathic surgery. The following cephalometric variables were measured on pre-treatment (T1) and post-treatment (T2) lateral cephalograms: sella-nasion-A-point (SNA), sella-nasion-B-point (SNB), and A-point-nasion-B-point (ANB) angles, Wits appraisal, facial axis angle, mandibular plane angle, upper and lower incisor inclination, and inter-incisal angle. There were statistically significant differences in cephalometric variables before and after treatment between the two groups. The percentage of normal pre-treatment measurements in the camouflage orthodontics group was 30.7%, which worsened slightly to 28.4% post-treatment. However in the group receiving surgery, this was 24.5% pre-treatment, improving to 33.5% after surgery. SNA, SNB, Wits appraisal, lower incisor inclination, and inter-incisal angle showed differences between the two groups before and after treatment. Wits appraisal, lower incisor inclination, and inter-incisal angle were indicative of one or other treatment. Upper and lower incisor decompensation in both groups did not reach ideal values, which impeded complete skeletal correction in 52% of surgical cases.

A comparison between dental measurements taken from CBCT models and those taken from a digital method.

The aims of the study were to assess speed, reliability, accuracy, and reproducibility in measuring mesiodistal tooth sizes, bicanine widths, bimolar widths, and arch lengths (ALs) using cone beam computed tomography (CBCT) and to compare them with the same measurements obtained using a two-dimensional (2D) Digital Method. Plaster study models were made for 27 patients and then digitalized and measured using a 2D Digital Method. CBCTs were undertaken on the same 27 patients using the Dental Picasso Master 3D® and the images obtained were then analysed using the InVivoDental program. The correlation study of the two measuring methods, which were compared by determining the regression parameters and the values of one method as opposed to the other, show how both methods are comparable, although the mean and standard deviation of all the measurements analysed present statistically significant differences for the first upper right premolar, first upper left molar, first lower left premolar, and second lower right premolar, as well for the lower intercanine distance and lower AL. The differences, however, are less than 1 per cent. CBCT digital models are as accurate and reliable as the digital models obtained from plaster casts. The differences existing between both methods are clinically acceptable.

Diseño de una cefalometría tridimensional con la tomografía computarizada de haz cónico (CBCT ) / No disponible

Introducción: el uso de los CBCT se está imponiendo actualmente en los pacientes ortodóncicos ya que estos sistemas suponen una alternativa a la radiografía convencional y a la tomografía computarizada(TC). Objetivos: Definir una serie de planos de referencia y medidas lineales y diseñar una cefalometría en tres dimensiones que incluya un análisis esquelético, de asimetrías, de proporciones craneofaciales y dentoalveolar. Conclusiones: En el presente estudio se muestra una cefalometría sencilla en tres dimensiones, que puede servir para poder medir directamente a nuestros pacientes en los cortes y en la reconstrucción tridimensional obtenidas con un equipo CBCT, sin necesidad de emplear la telerradiografía convencional (AU)

Introduction: The use of CBCT is currently imposing on orthodontic patients because these systems offer an alternative to conventional radiography and computed tomography (CT). Objectives: Define a set of reference planes and linear measurements and design a three-dimensional cephalometric analysis including a skeletal analysis, an analysis of asymmetries, a craniofacial relationships analysis and adentoalveolar analysis. Conclusions: This study shows a simple three-dimensional cephalometry, which can serve to measure directly our patients with CBCT equipment, without using conventional teleradiography (AU)

Prediction of arch length based on intercanine width.

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 correlation coefficient. Linear regression analysis was applied and the 95 per cent confidence intervals (CIs) for slope and intercept were determined. The data showed very high correlations between ICW and AL, both for the upper and lower arches and for males and females, r = 0.925. This coefficient was very close to 1, indicating a linear relationship. The regression equation for AL and ICW was AL = 1.36 ICW + 29.39 for both arches. There was very high correlations between AL and ICW for the upper and lower arches and a regression equation between both magnitudes was established indicating that the size of one factor can be predicted by knowing the other. For an increase of 1 mm in ICW, the AL increases approximately 1.36 mm with a 95 per cent CI (1.30-1.42).

Determination of Bolton tooth-size ratios by digitization, and comparison with the traditional method.

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 calculating the coefficients of variation. The results demonstrated that the digital method provided results comparable with those of the traditional technique, since the regression parameters for each index showed that the correlation coefficients of the two methods were very high and similar to each other: r = 0.976 and r = 0.979 for the ABI and OBI, respectively. The results also showed more discrepancies in the ABI than in the OBI using both methods in this sample.

Forced eruption of a labially impacted maxillary canine with a transcoronal stainless wire: report of case.

An orthodontic-surgical treatment of a high labially impacted maxillary canine is described. The use of a transcoronal wire is recommended as a rapid and safe method to force the eruption of the unfavorable impacted canines. Minimal surgical exposure of the crown is necessary to place a transcoronal wire which can be easily inserted during surgery. Although the canine in the presented case was in an unfavorable position, and the root already formed, it was moved from its initial high position to occlusion in about one year with no loss of vitality and no periodontal anomalies.

Primary double teeth. A retrospective clinical study of their morphological characteristics and associated anomalies.

AIM: To investigate the relationship between morphology and position of double teeth, and the occurrence of other dental anomalies in the same subjects and in their siblings. SAMPLE OF CHILDREN AND METHODS: Fifty-three double teeth in a group of 50 Spanish children were included in the study. All of these children were examined clinically and had radiographs and photographs taken at the time of examination. Twenty-two of the children had a total of 30 siblings who were also examined for the presence of anomalies. RESULTS: Of the 50 subjects, 47 had one and three subjects had two double teeth. Statistically there were no significant differences in occurrence between boys and girls, left and right sides or between maxilla and mandible. Four morphological types were identified: type I, bifid crown-single root; type II, large crown-large root; type III, two fused crowns-single root; type IV, two fused crowns-two fused roots. Type I was seen only in the maxilla and types II and III only in the mandible. Type IV was seen mostly in the maxilla. More than half of the cases showed associated anomalies in the permanent dentition and anomalies of number or shape were also present in six of the siblings. CONCLUSION: It is suggested that both double teeth and other anomalies in the same children or in their siblings may be manifestations of a primary abnormality in the distribution of dental material.

Transient red discoloration: report of case.

The different evolutions of a red discoloration of the primary maxillary central incisors in the same patient are charted. In the right central incisor the red discoloration disappeared; in the left it faded but was sustained until exfoliation. This case supports the theoretical existence of a transient type of discoloration following trauma. The resorption of posttraumatic intrapulpal bleeding in a primary tooth is discussed as a possible pathogenesis.

Dentigerous cyst of mandibular second premolar in a five-year-old girl, related to a non-vital primary molar removed one year earlier: a case report.

A dentigerous cyst of the mandibular second premolar in a 5-year-old female was radiographically diagnosed. A non-vital primary predecessor molar had been removed a year earlier. At that time, the primary molar had been in the mouth for approximately two years. Although there was the possibility of the premolar being non-vital, as a consequence of the cystic cavity surrounding it, marsupialization treatment of the cyst was done, causing a rapid development of the premolar. Structural irregularities in the enamel and in the first radicular portion were visible, possibly caused by the very early beginning of the cyst formation.

Eruption cysts: retrospective clinical study of 36 cases.

The eruption cyst is a lesion associated with an erupting tooth. It appears as a transparent, bluish, blue or blue-black swelling of the alveolar mucosa, over a temporal or permanent tooth in eruption. The analysis of the thirty-six eruption cysts cases studied, corresponding to twenty-seven patients, revealed that their most frequent location is in the maxillary permanent dentition, and that they mostly occur in a single presentation, and in an age-range of between five and nine years. Six cases out of the twenty-seven patients studied showed the characteristic of presenting two or more eruption cysts, and in three of these cases, the lesions were bilateral, symmetrical and simultaneous. Two other patients had been previously diagnosed with cyst diseases. This would suggest that, in addition to the possible infection-trauma origin, there is in some cases the possibility of a predisponent tendency.

Late development of maxillary supernumerary tooth: a case report.

A case is presented of a late developing maxillary supernumerary tooth in the permanent dentition. The patient had a supernumerary tooth fused to a central incisor in the primary dentition. This case emphasizes the importance of careful follow-up of patients with a history of supernumerary teeth and, where clinically indicated, of further radiographic examination.

Effects of maxillary protraction determined by laser metrology.

In this work we studied some of the main effects of the maxillary protraction orthopedic device. The initial dento-craniofacial reactions induced by maxillary protraction similar to that commonly employed in clinical practice are reported. The fringe counting holographic interferometry technique is used to measure displacements. The experiments were performed on a dried human skull; traction application points were situated over the permanent lateral incisors or over the first permanent molars. The results fundamentally reveal an anterior rotation of the dentomaxillary complex, more intense when traction is applied to the lateral incisors, as shown by a more marked extrusion of the molars in this case. Moreover, major deformation patterns could be observed in inner hard structures of the skull base when applying orthopaedic forces.