Aging changes in maxillary anterior teeth in untreated individuals: an observational longitudinal study.

OBJECTIVE: The aging of the occlusion and tooth wears influence the smile design This study aimed at evaluating the aging changes of maxillary anterior teeth in nontreated subjects. METHODS: The sample comprised dental models of 23 subjects (13 male, 10 female) with normal occlusions, taken at 13 (T1), 17 (T2) and 61 (T3) years of age. The following variables were measured in the maxillary anterior teeth using digital dental models: crown width/height proportion, anterior view width, crown angulation, gingival and incisal steps between central/lateral incisors and central incisors/canines. Interphase comparisons were evaluated using repeated measures analysis of variance followed by Tukey tests or Friedman tests. Sexual differences were evaluated using t tests (P < 0.05). RESULTS: From 13 to 61 years of age, a decrease of crown width/height proportion (P = 0.008 and P = < 0.001, for the lateral incisor and canines, respectively) and mesiodistal angulation (P = < 0.001, P = 0.001 and P = 0.025 for the central incisor, lateral incisor and canines, respectively) of the maxillary anterior teeth were observed. The steps of the gingival margin and the incisal steps decreased with aging. CONCLUSIONS: From adolescence to late adulthood, untreated individuals with normal occlusions demonstrated changes in the maxillary anterior teeth that may impair the smile esthetics and attractiveness.

Relación entre distancia intercantal y ancho de dientes anterosuperiores en jóvenes chilenos / Relationship between intercanthal distance and width of maxillary anterior teeth in young chilean population

RESUMEN: Objetivo: La distancia intercantal (DIC) es utilizado para la selección de los dientes anterosuperiores y es la dimensión más estable en el tiempo Sin embargo, es variable entre razas y poblaciones, particularmente en Sudamérica. El objetivo de este estudio es establecer la correlación entre DIC y el ancho de los dientes maxilares anteriores en una población adulta jóven del sur de Chile. Materiales y métodos: Estudio de corte transversal. Participaron 111 estudiantes voluntarios (promedio edad 22.4 años; 65.7% hombres) de la ciudad de Valdivia, sur de Chile. Se midió DIC y el ancho mesiodistal del incisivo central superior, la distancia lineal de los cuatro incisivos superiores y de los seis dientes anterosuperiores en modelos de estudio. Se analizó la diferencia de las mediciones según sexo (test de Student; p<0.05) y la correlación lineal entre DIC y las medidas dentales (r=0.8; p<0.05. STATA v.10.0) Resultados: Todas las mediciones fueron significativamente mayores en hombres que en mujeres (p<0.05). Se observó una correlación estadísticamente significativa entre la DIC y la distancia lineal de los cuatro incisivos superiores (p=0.04) y de los seis dientes anterosuperiores (p=0.03). Se obtuvo una razón de 1:0.94 y 1:1.28 de DIC con la distancia lineal de los cuatro incisivos superiores y los seis dientes anterosuperiores, respectivamente. Conclusión: La DIC presentó una correlación lineal y proporcional con los dientes anteriores, pudiendo estimar el ancho lineal de los dientes anterosuperiores en una población adulta joven del Sur de Chile.

ABSTRACT: Objective: Intercanthal distance (ICD) is a parameter used to select the upper anterior teeth and the most stable measurement overtime. However, it is variable between race and populations, particularly in South America. The aim of this study was to establish the correlation between ICD and the width of maxillary anterior teeth in young adult population from southern of Chile. Materials and Methods: A Cross-sectional study was designed. One Hundred eleven volunteers students (average age 22.4 years; 65.7% men) from Valdivia city (southern of Chile) were included. ICD and mesiodistal width of maxillary central incisor, linear distance of the four upper incisors and linear distance of the six upper front teeth in plaster study models weremeasured. The mean of difference measurement between sex (ttest; p<0.05) and the linear correlation between DIC and the width of the upper anterior were analyzed (r=0.8; p<0.05; STATA v.10.0). Results: All measurement were significantly higher in male than female (p<0.05). A statistically significant correlation between ICD and distance of the four upper incisors (p=0.04) and the six upper front teeth (p=0.03) were observed. A 1:0.94 and 1:1.28 ratios between ICD with the linear distance of the upper incisors and the six maxillary anterior were obtained respectively. Conclusion: ICD presented a linear and proportional correlation with maxillary anterior teeth. With these results it is possible to estimate the linear width of the upper front teeth in young adult population from southern of Chile.

Recidiva do apinhamento anterossuperior nas más oclusões de Classe I e Classe II tratadas ortodonticamente sem extrações / Relapse of maxillary anterior crowding in Class I and Class II malocclusions orthodontically treated without extractions

OBJETIVO: o presente estudo objetivou comparar retrospectivamente a estabilidade pós-contenção do alinhamento dos incisivos anterossuperiores em pacientes com Classe I e Classe II. MÉTODOS: a amostra consistiu de 38 pacientes de ambos os sexos, tratados sem extrações e com mecânica Edgewise, divididos em dois grupos - Grupo 1, constituído por 19 pacientes, com idade inicial média de 13,06 anos, portadores da má oclusão de Classe I com apinhamento anterossuperior inicial maior que 3mm; Grupo 2, constituído por 19 pacientes, com idade inicial de 12,54 anos, portadores da má oclusão de Classe II e, também, com apinhamento anterossuperior inicial maior que 3mm. Foram medidos nos modelos de estudo, das fases pré- e pós-tratamento e pós-contenção, o índice de irregularidade de Little, as distâncias intercaninos e entre os primeiros e segundos pré-molares, a distância intermolares e o comprimento da arcada superior. Para a comparação intragrupo nos 3 tempos de avaliação, utilizou-se os testes ANOVA e Tukey. A comparação intergrupos foi realizada pelo teste t independente. Para verificação da presença de correlação, utilizou-se o teste de correlação de Pearson. RESULTADOS: os resultados evidenciaram maior estabilidade do tratamento no Grupo 2 (Classe II), pois, durante o período pós-contenção, foi observada recidiva do apinhamento dos dentes anterossuperiores menor no Grupo 2 (0,80mm) do que no Grupo 1 (1,67mm). CONCLUSÃO: concluiu-se que o tratamento do apinhamento dos dentes anterossuperiores é mais estável na má oclusão de Classe II do que na má oclusão de Classe I.

OBJECTIVE: The present study aimed to retrospectively compare the postretention stability of maxillary anterior incisors alignment in Class I and Class II patients. METHODS: The sample comprised 38 patients of both genders, treated with nonextraction and Edgewise mechanics, divided into two groups: Group 1, comprised of 19 patients, at a mean age of 13.06 years, with Class I malocclusion and initial maxillary anterior crowding greater than 3 mm; Group 2, comprised of 19 patients, at a mean age of 12.54 years, with Class II malocclusion, and also with a initial maxillary anterior crowding greater than 3 mm. In the dental casts of pretreatment, posttreatment and postretention phase, the Little's irregularity index, intercanine distance and distance between first and between second premolars, intermolar distance and maxillary arch length were measured. For intragroup comparison among the three times of evaluation, it was used the one-way ANOVA followed by Tukey test. Intergroup comparison was performed by independent t tests. To verify the presence of correlation, the Pearson correlation test was used. RESULTS: It was evidenced greater stability of treatment in Group 2 (Class II), because during the postretention period it was observed a softer relapse of maxillary anterior crowding in Group 2 (0.80mm) than in Group 1 (1.67mm). CONCLUSION: It can be concluded that the treatment of maxillary anterior crowding is more stable in Class II malocclusion than in Class I malocclusion.