Relapse of incisor crowding: a visit to the prince of salina

The management of the retention period after comprehensive orthodontic treatment is of great importance, as a primary goal of clinician. Considerable controversy still surrounds the problem of stability after the retention period. Many studies analyze factors associated to the presence of crowding or incisor irregularity and find predictive features on its relapse. Most studies have reported little o no correlation between the treatment changes in the biological parameters - clinical, biometric (irregularity index, intermolar width, intercanine width, arch length, overjet, overbite), or cephalometric variables- that ocurred and the posttretament and postretention changes that may predict their future development. This article provides a bibliographical overview on the relapse of dental alignment in treated cases. In a brief historical introduction, the first studies on the long-term stability of orthodontic results are analysed. The article then goes on to assess studies that focus attention on anteroinferior alignment before finally studying relapse of upper crowding. It concludes by making some final comments in the light of the bibliography provided and the differents schools regarding retention needs and methods

Long-term analysis of upper incisor crowding. A longitudinal study orthodontically treated patients

Introduction: Although there are numerous studies in the literature on alignment stability in the lower arch, there are few referring to the upper arch. Aims: To assess upper arch stability (irregularity index, widths and length of arch, overjet and overbite) in orthodontically treated patients by comparing late incisor stability with the initial malocclusion and type pf treatment undertaken. Study design: The study models of 51 patients, treated with or without extractions, were analysed at three different points in time: pre-treatment (T1), post-treatment (T2) and post-retention (T3) (average 5 years). The following parameters were measured: irregularity index, arch length, inter-canine and inter-molar widths, overjet and overbite. Results: The results showed that upper incisor crowding relapses, although a net improvement is noted in comparison to the initial state both in cases treated with or without extractions. The arch length also relapses in both cases. The inter-canine and inter-molar widths as well as the overjet and overbite are stable in the long term. The long-term response of maxillary incisor alignment is unpredictable. Conclusions: There is a statistically significant reduction in incisor irregularity, length and width of arch (inter-canine and inter-molar widths), whereas overjet and overbite undergo a reduction of little magnitude. No statistically significant correlation is noted between late incisor stability and the initial malocclusion or type of treatment

Digital diagnosis records in orthodontics : An overview

Actualmente la tecnología digital es una realidad que cada vez se impone más en todos los ámbitos clínicos y, por tanto, existe una incorporación también de los ortodoncistas a la digitalización de los registros ortodóncicos diagnósticos. En este trabajo queremos hacer una valoración sobre las ventajas y desventajas, del uso de la radiografía digital, la fotografía digital así como de la última incorporación, los modelos de estudio digitalizados. Basados en encuestas previas, mostraremos la situación actual en nuestro país en cuanto al número de profesionales que utilizan estos registros digitales de manera sistemática

Evaluation of treatment outcomes in a 3 years post-graduate orthodontic program using the peer assessment rating (par)

Objectives: To maintain high treatment quality it is important to evaluate orthodontic treatment results using objec - tive methods. Outcome assessments allow private practitioners and university students to evaluate their results and raise the level of treatment outcomes. The aim of this study was to assess the orthodontic treatment outcome in a post-graduate orthodontics program in the University of Valencia (Spain) and to determine whether the treatment outcome is related to several factors as gender, age at start of the treatment, treatment duration, treatment method, extraction-non extraction treatment and cooperation needed. Material and Methods: A sample of 50 patients treated in the post-graduate clinic was randomly selected. Pre- treatment and post-treatment study casts have been assessed by the Peer Assessment Rating (PAR index). The in - fluence of various factors: gender, age at start of the treatment, treatment duration, treatment method, extraction-non extraction treatment, cooperation needed and number of students finishing each case, were statistically analyzed. Results: According to the PAR index, orthodontic treatment reduced the malocclusion in a mean point reduction of 21.4 (CI 95% 18.7-24.1) and a mean percentage reduction of 80.5% (CI 95% 75.9-85.1). The total of the cases improved, 44% of the patients were in greatly improved category. Conclusions: None of the variables studied influenced significantly the treatment outcomes regarding the PAR. Ba - sed on the general classification criteria of the index, the results showed that the patients received a high standard treatment

Dental arch changes from adolescence to adulthood in a spanish population : a cross-sectional study

Objectives: Given the controversy in the literature about the variations in intercanine and intermolar distances and arch perimeter once the eruption of permanent teeth is completed, the aims of this study were to assess the changes of these measures with age, analyzing its sexual dimorphism and variability in a Spanish population. Study Design: 188 Spanish individuals distributed in three age groups were selected: 63 adolescents (mean age: 14.15 years), 62 young adults (mean age: 21.9 years) and 63 adults (mean age: 40 years). The intercanine and intermolar distances and arch perimeter were measured in each dental cast from each individual of the sample using a digital method. The results were compared between sex and age groups, the sexual dimorphism percentage (%) of each measure and its variability coefficient (VC%) were calculated. Results: The results depend on sex and age and, therefore, these two factors will be analyzed jointly for each of them with the variation coefficient of the measurement. Intercanine and intermolar distances and arch perimeter were greater in men than in women, especially in the young adult and adult groups. Conclusions: The intercanine distance and arch perimeter tended to decrease with age particularly in the female sex, whilst the intermolar distance didn't undergo significant changes. The intercanine distance is the dimension that presented the greatest variability, whereas the intermolar distance presented the least. The changes occur in the transition from adolescence (14 years of age) to adulthood (22 years of age) and the subsequent alterations are not relevant. © Medicina Oral S. L

A new 3D method for measuring cranio-facial relationships with cone beam computed tomography (CBCT)

Objectives: CBCT systems, with their high precision 3D reconstructions, 1:1 images and accuracy in locating cephalometric landmarks, allows us to evaluate measurements from craniofacial structures, so enabling us to replace the anthropometric methods or bidimensional methods used until now. The aims are to analyse cranio-facial relationships in a sample of patients who had previously undergone a CBCT and create a new 3D cephalometric method for assessing and measuring patients. Study Design: 90 patients who had a CBCT (i-Cat®) as a diagnostic register were selected. 12 cephalometric landmarks on the three spatial planes (X,Y,Z) were defined and 21 linear measurements were established. Using these measurements, 7 triangles were described and analysed. With the sides of the triangles: (CdR-Me-CdL); (FzR-Me-FzL); (GoR-N-GoL); and the Gl-Me distance, the ratios between them were analysed. In addition, 4 triangles in the mandible were measured (body: GoR-DB-Me and GoL-DB-Me and ramus: KrR-CdR-GoR and KrL-CdL-GoL). Results: When analyzing the sides of the CdR-Me-CdL triangle, it was found that the 69.33% of the patients could be considered symmetric. Regarding the ratios between the sides of the following triangles: CdR-Me-CdL, FzR-Me-FzL, GoR-N-GoL and the Gl-Me distance, it was found that almost all ratios were close to 1:1 except between the CdR-CdL side with respect the rest of the sides. With regard to the ratios of the 4 triangles of the mandible, it was found that the most symmetrical relationships were those corresponding to the sides of the body of the mandible and the most asymmetrical ones were those corresponding to the base of such triangles. Conclusions: A new method for assessing cranio-facial relationshps using CBCT has been established. It could be used for diverse purposes including diagnosis and treatment planning

Tooth size changes with age in a Spanish population : percentile tables

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 each group of age and gender were drawn up. Percentiles under 30 were considered as small, between 30 and 70 as average, and above 70 as large. As symmetry was found between contralateral teeth, the mean between the teeth of the two semi-arches was considered. Results: The mesiodistal tooth sizes of adolescents did not present statistically significant differences between genders, in contrast to the two other age groups. Conclusions: Mesiodistal tooth diameters tended to diminish with age, especially in women, in the Spanish population. The values obtained for our dental tables, organized by percentiles, were slightly higher than those found by Sanin and Savara in an American population, especially for women. © Medicina Oral S. L

Study between anb angle and wits appraisal in cone beam computed tomography (cbct)

Objectives: To analyse the ANB and Wits values and to study correlations between those two measurements and other measurements in diagnosing the anteroposterior maxilo-mandibular relationship with CBCT. Study Design: Ninety patients who had previously a CBCT (i-CAT ® ) as a diagnostic register were selected. A 3D cephalometry was designed using one software package, InVivo5 ® . This cephalometry included 3 planes of reference, 3 angle measurements and 1 linear measurement. The means and standard deviations of the mean of each measurement were assessed. After that, a Pearson's correlation coefficient has been performed to analyse the significance of each relationship. Results: When classifying the sample according to the anteroposterior relationship, the values obtained of ANB (Class I: 53%; Class II: 37%; Class III: 10%) and Wits (Class I: 35%; Class II: 56%; Class III: 9%) did not coincide, except for the Class III group. However, of the patients classified differently (Class I and Class II patients) by ANB and Wits, a high percentage of individuals (n=22; 49%), had a mesofacial pattern with a mandibular plane angle within normal values. A correlation has been found between ANB and Wits (r=0,262), occlusal plane angle and ANB (r=0,426), and mandibular plane angle and Wits (r=0,242). No correlation was found between either Wits or ANB in relation with the age of the individuals. Conclusions: ANB and Wits must be included in 3D cephalometric analyses as both are necessary to undertake a more accurate diagnosis of the maxillo-mandibular relationship of the patients

Evaluation of the validity of the Bolton Index using cone-beam computed tomography (CBCT)

Aims: To evaluate the reliability and reproducibility of calculating the Bolton Index using cone-beam computed tomography (CBCT), and to compare this with measurements obtained using the 2D Digital Method. Material and Methods: Traditional study models were obtained from 50 patients, which were then digitized in order to be able to measure them using the Digital Method. Likewise, CBCTs of those same patients were undertaken using the Dental Picasso Master 3D® and the images obtained were then analysed using the InVivoDental programme. Results: By determining the regression lines for both measurement methods, as well as the difference between both of their values, the two methods are shown to be comparable, despite the fact that the measurements analysed presented statistically significant differences. Conclusions: The three-dimensional models obtained from the CBCT are as accurate and reproducible as the digital models obtained from the plaster study casts for calculating the Bolton Index. The differences existing between both methods were clinically acceptabl

Influence of first and second premolar extraction or non-extraction treatments on mandibular third molar angulation and position. A comparative study

The mandibular third molar (3M) is the tooth that is most often impacted, with lack of space being one of the reasons. In some orthodontic treatments, premolars are extracted in order to create space. The aims of our study are: firstly, to assess the changes in the angulation and position of the 3M in cases treated either with or without extraction of the first or second premolars; secondly, to analyse the variation in the gonial angle and the degree of inclusion of the 3M; and lastly, to establish a predictive impaction model for 3M. This study included 88 patients: 28 patients treated with extractions of first premolars, 30 with second premolars and 30 without. The initial and final orthopantomography was analysed and the angulation of the 3M was measured, a new variable being created to determine the degree of 3M inclusion in the mandibular ramus. The results show that the angulation of 3M improves with time, regardless of treatment, and presents a greater disinclusion in cases treated with extractions. The gonial angle tends to diminish with age in all cases. The conclusions suggest that other factors may influence the angulation and position of 3M and that it is not possible to establish a predictive impaction model