ABSTRACT
OBJECTIVE: To investigate how bracket slot size affects the direction of maxillary anterior tooth movement when en-masse retraction is performed in sliding mechanics using an induction-heating typodont simulation system. METHODS: An induction-heating typodont simulation system was designed based on the Calorific Machine system. The typodont included metal anterior and resin posterior teeth embedded in a sticky wax arch. Three bracket slot groups (0.018, 0.020, and 0.022 inch [in]) were tested. A retraction force of 250 g was applied in the posterior-superior direction. RESULTS: In the anteroposterior direction, the cusp tip of the canine in the 0.020-in slot group moved more distally than in the 0.018-in slot group. In the vertical direction, all six anterior teeth were intruded in the 0.018-in slot group and extruded in the 0.020- and 0.022-in slot groups. The lateral incisor was significantly extruded in the 0.020- and 0.022-in slot groups. Significant differences in the crown linguoversion were found between the 0.018- and 0.020-in slot groups and 0.018- and 0.022-in slot groups for the central incisor and between the 0.018- and 0.022-in slot groups and 0.020- and 0.022-in slot groups for the canine. In the 0.018-in slot group, all anterior teeth showed crown mesial angulation. Significant differences were found between the 0.018- and 0.022-in slot groups for the lateral incisor and between the 0.018- and 0.020-in slot groups and 0.018- and 0.022-in slot groups for the canine. CONCLUSIONS: Use of 0.018-in slot brackets was effective for preventing extrusion and crown linguoversion of anterior teeth in sliding mechanics.
Subject(s)
Crowns , Incisor , Mechanics , Tooth Movement Techniques , ToothABSTRACT
The first Edgewise brackets were utilized with gold wire and the slot designed with 0.022" high to present sufficient rigidity. When gold was replaced by stainless steel, cheaper and stiffer, it was proposed to reduce the slot size to 0.018". The two different sizes of brackets are used in contemporary orthodontics and many clinical orthodontists are unaware of the advantages they may have. The aim of this paper is to present, based on the orthodontic literature, the main characteristics influenced by the brackets slot size and compile data to drive orthodontists in choosing the bracket that best meets their clinical needs.
Os primeiros braquetes Edgewise eram utilizados com fios de ouro e concebidos com o slot de 0,022" de altura, para que apresentassem rigidez suficiente. Com a substituição do ouro pelo aço inoxidável, mais barato e mais rígido, foi proposta a redução do slot para 0,018". As duas diferentes dimensões de braquetes são utilizadas na Ortodontia contemporânea e muitos ortodontistas clínicos desconhecem suas vantagens. O objetivo deste artigo foi apresentar, baseando-se na literatura ortodôntica, as principais características influenciadas pelo tamanho do slot dos braquetes e compilar os dados para direcionar o ortodontista na escolha do braquete que melhor atenda às suas necessidades clínicas.
Subject(s)
Orthodontic Brackets , Orthodontics/instrumentation , TorqueABSTRACT
OBJECTIVE: This study was designed to measure the surface roughness at the slot floor of various ceramic brackets. METHODS: One kind of stainless steel bracket (Succes(R)), two kinds of monocrystalline brackets (Inspire Ice(R), Perfect(R)) and two kinds of polycrystalline brackets (Crystalline V(R), Invu(R)) were examined. Atomic force microscopy (AFM) was used to measure the surface roughness of each bracket. Data acquisition and processing were performed using SPIP(TM). RESULTS: The differences in values of Sa, Sq, and Sz in Invu(R) and Inspire Ice(R) were not statistically different from the control group Succes(R). The values of Sa, Sq, and Sz of Perfect(R) and Crystalline V(R) were greater than those of Succes(R). Differences of all the Sa, Sq, and Sz values between Perfect(R) and Crystalline V(R) were not statistically significant. CONCLUSIONS: It is concluded that the slot surfaces of Succes(R), Inspire Ice(R), and Invu(R) were smooth compared to those of Crystalline V(R) and Perfect(R).