Características anatomorradiográficas de los terceros molares en adolescentes de la enseñanza preuniversitaria / Anatomo-radiographic characteristics of third molars in senior high school students

RESUMEN Introducción: Las retenciones dentarias afectan al 17 % de los pacientes a nivel mundial y están consideradas actualmente como un síndrome, en que los terceros molares ocupan el primer lugar y cuya extirpación quirúrgica deviene la intervención más comúnmente practicada por los cirujanos maxilofaciales. Objetivo: Describir las características anatomorradiográficas de los terceros molares, así como su posible relación con variables epidemiológicas de interés. Métodos: Se realizó un estudio observacional, descriptivo y transversal en escolares del Instituto Preuniversitario "Antonio Alomá Serrano", perteneciente al área de salud del Policlínico Docente Asistencial "José Martí" de Santiago de Cuba, durante el período comprendido desde mayo de 2016 hasta febrero de 2017. Se utilizaron radiografías panorámicas indicadas a estos pacientes, en las que se efectuaron el análisis y la clasificación. Resultados: La mayoría de los dientes se encontraban en clase I (52,6 por ciento), clase C (51,9 por ciento), posición C (82,2 por ciento), verticales (47,7 por ciento) y sin aproximación sinusal (89,5 por ciento). Además se observaron relaciones significativas entre la edad y el color de la piel con respecto al espacio retromolar y la inclinación dentaria de este grupo molar, y entre el sexo y la inclinación. Conclusiones: Los terceros molares son los dientes con mayor variabilidad en cuanto a posición e inclinación intraósea y en edades avanzadas se logra suficiente espacio retromolar y verticalización en la mayoría de ellos(AU)

ABSTRACT Introduction: Tooth impaction affects 17 % of patients worldwide. It is currently considered to be a syndrome in which third molars occupy the first place. Surgical removal is the most common intervention performed by maxillofacial surgeons. Objective: Describe the anatomo-radiographic characteristics of third molars and their possible relationship to epidemiological variables of interest. Methods: A cross-sectional observational descriptive study was conducted of students from Antonio Alomá Serrano Senior High School, from the health area of José Martí University Polyclinic in Santiago de Cuba, from May 2016 to February 2017. The study was based on panoramic radiographs, which were analyzed and classified. Results: Most teeth were class I (52.6 percent), class C (51.9 percent), position C (82.2 percent), vertical (47.7 percent) and without sinus approach (89.5 percent). Significant relationships were found between age and skin color with respect to retromolar space and tooth inclination of this molar group, and between sex and inclination. Conclusions: Third molars are the teeth showing the greatest variability in terms of intraosseous inclination and position. In advanced ages most of them achieve enough retromolar space and verticalization(AU)

Inclination of crown and tooth longitudinal axis in cephalometric analysis of normal occlusions / 华西口腔医学杂志

<p><b>OBJECTIVE</b>We measured and analyzed the angle between the longitudinal axis of incisor crown and tooth to provide a reference for orthodontists for selecting orthodontic methods and evaluating treatment results.</p><p><b>METHODS</b>A total of 120 participants were included according to the criteria of Andrews' six keys, and cephalometric radiograph under the instructions of modified natural head position acquirement method was performed. The angles of maxillary incisor crown longitudinal axis, tooth longitudinal axis, occlusion plane (OP), and true vertical (TV) plane were measured, as well as mandibular incisors.</p><p><b>RESULTS</b>As for maxillary incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 11.72°±4.71°, 73.29°±5.69°, and 20.04°±3.71°, respectively. For mandibular incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 16.03°±5.40°, 81.76°±4.81°, and 14.82°±4.01°, respectively. For the maxillary incisor, the angles between crown longitudinal axis and tooth longitudinal axis were mainly within 15° to 25°, whereas those for mandibular incisors were within 10° to 20°.</p><p><b>CONCLUSIONS</b>The longitudinal axis inclinations of the maxillary and mandibular incisor crown and of the incisor tooth need to be considered when cephalometric radiographs are used for treatment planning or for evaluating the treatment result.</p>

Effect of labiolingual inclination of a maxillary central incisor and surrounding alveolar bone loss on periodontal stress: A finite element analysis / 대한치과교정학회지

OBJECTIVE: The aim of this study was to investigate whether labial tooth inclination and alveolar bone loss affect the moment per unit of force (M(t)/F) in controlled tipping and consequent stresses on the periodontal ligament (PDL). METHODS: Three-dimensional models (n = 20) of maxillary central incisors were created with different labial inclinations (5°, 10°, 15°, and 20°) and different amounts of alveolar bone loss (0, 2, 4, and 6 mm). The M(t)/F necessary for controlled tipping (M(t)/F(cont)) and the principal stresses on the PDL were calculated for each model separately in a finite element analysis. RESULTS: As labial inclination increased, M(t)/F(cont) and the length of the moment arm decreased. In contrast, increased alveolar bone loss caused increases in M(t)/F(cont) and the length of the moment arm. When M(t)/F was near M(t)/F(cont), increases in M(t)/F caused compressive stresses to move from a predominantly labial apical region to a palatal apical position, and tensile stresses in the labial area moved from a cervical position to a mid-root position. Although controlled tipping was applied to the incisors, increases in alveolar bone loss and labial tooth inclination caused increases in maximum compressive and tensile stresses at the root apices. CONCLUSIONS: Increases in alveolar bone loss and labial tooth inclination caused increases in stresses that might cause root resorption at the root apex, despite the application of controlled tipping to the incisors.

Avaliação da inclinação dentária no tratamento compensatório do padrão II com tomografia computadorizada / Assessment of tooth inclination in the compensatory treatment of pattern II using computed tomography

OBJETIVO: avaliar as alterações nas inclinações dos dentes anteriores causadas pelo tratamento ortodôntico, utilizando-se aparelho Straight-Wire, prescrição II Capelozza, antes e após a fase de nivelamento com fios ortodônticos de aço de secção retangular. MÉTODOS: foram selecionados 17 indivíduos adultos de padrão facial II, má oclusão Classe II, indicados para tratamento ortodôntico compensatório. As inclinações dos dentes anteriores foram avaliadas em três tempos clínicos, após o uso dos fios ortodônticos de diâmetros 0,020" (T1); 0,019" x 0,025" (T2) e 0,021" x 0,025" (T3), através de exames de tomografia computadorizada. Empregou-se a análise de variância de Friedman, com nível de significância de 5 por cento, na comparação entre os tempos. RESULTADOS: observou-se que o fios retangulares empregados não foram capazes de produzir uma mudança significativa na mediana da inclinação dentária, exceto por uma discreta alteração nos incisivos laterais inferiores (p<0,05). Por outro lado, constatou-se que a variação das inclinações observadas era menor no fio retangular 0,021" x 0,025", principalmente para os incisivos superiores (p<0,001). CONCLUSÃO: fios retangulares 0,021" x 0,025" produzem uma maior homogeneidade no grau de variação na inclinação dos incisivos superiores, embora sem mudança significativa na sua mediana.

OBJECTIVE: To evaluate changes in the inclination of anterior teeth caused by orthodontic treatment using a Straight-Wire appliance (Capelozza's prescription II), before and after the leveling phase with rectangular stainless steel archwires. METHODS: Seventeen adult subjects were selected who presented with facial pattern II, Class II malocclusion, referred for compensatory orthodontic treatment. Inclinations of anterior teeth were clinically assessed using CT scans at three different times, i.e., after the use of 0.020-in (T1), 0.019 X 0.025-in (T2) and 0.021 X 0.025-in (T3) archwires. Friedman's analysis of variance was applied with 5 percent significance level to compare the three assessments (T1, T2 and T3). RESULTS: It was noted that the rectangular wires were unable to produce any significant changes in inclination medians, except for a slight change in mandibular lateral incisors (p<0.05). On the other hand, variations in inclination were smaller when 0.021 X 0.025-in archwires were employed, particularly in maxillary incisors (P<0.001). CONCLUSION: The use of rectangular 0.021 X 0.025-in archwires produces more homogeneous variations in the inclination of maxillary incisors, but no significant median changes.