A Staged Expansion Screw Protocol to Retract the Premaxilla In BCLP Infants with Delayed Nasoalveolar Molding.

Currently, the treatment protocol for cleft palate at several centers around the world involves primary lip repair around 3-4 months of age, using presurgical nasoalveolar molding, which is done soon after birth. Unfortunately, in cases where treatment is delayed, the potential for repositioning the nasoalveolar apparatus is severely limited. The purpose of this paper is to illustrate a novel use of an expansion screw appliance to aid in the faster and more efficient active molding of the premaxillary and lateral maxillary segments in infants for whom the start of PNAM therapy is delayed, without the side effects commonly seen with pin-retained active molding appliances.

Torque Control During Intrusion on Upper Central Incisor in Labial and Lingual bracket System - A 3D Finite Element Study.

BACKGROUND: The aim of present study was to investigate the difference of torque control during intrusive force on upper central incisors with normal, under and high torque in lingual and labial orthodontic systems through 3D finite element analysis. MATERIAL AND METHODS: Six 3D models of an upper right central incisor with different torque were designed in Solid Works 2006. Software ANSYS Version 16.0 was used to evaluate intrusive force on upper central incisor model . An intrusive force of 0.15 N was applied to the bracket slot in different torque models and the displacements along a path of nodes in the upper central incisor was assessed. RESULTS: On application of Intrusive force on under torqued upper central incisor in Labial system produce labial crown movement but in Lingual system caused lingual movement in the apical and incisal parts. The same intrusive force in normal-torqued central incisor led to a palatal movement in apical and labial displacement of incisal edge in Lingual system and a palatal displacement in apical area and a labial movement in the incisal edge in Labial systemin. In overtorqued upper central incisor, the labial crown displacement in Labial system is more than Lingual system. CONCLUSIONS: In labial and lingual system on application of the same forces in upper central incisor with different inclinations showed different responses. The magnitudes of torque Loss during intrusive loads in incisors with normal, under and over-torque were higher in Labial system than Lingual orthodontic appliances. Key words:FEM, lingual orthodontics, intrusion, torque control, labial bracket systems.

Bond efficacy of recycled orthodontic brackets: A comparative in vitro evaluation of two methods.

CONTEXT: Recycling of orthodontic brackets in developing orthodontic economies is an extremely common procedure. Bonding protocols and reliability of these brackets is, however, questionable, and still the subject of research. AIMS: The aim was to evaluate and compare the shear bond strength of brackets recycled with sandblasting and silicoating. MATERIALS AND METHODS: Ninety extracted human premolars were bonded with 0.022" SS brackets (American Orthodontics, Sheboygan USA) and then debonded. The debonded brackets were divided into three groups of 30 each. Group I: Sandblasting with 50-µm aluminum oxide (control group) Group II: Sandblasting with 50-µm aluminum oxide followed by metal primer application Group III: Silicoating with 30-µm Cojet sand followed by silane application and rebonded with Transbond XT. The sandblasted brackets and silicoated brackets were viewed under the scanning electron microscope, immediately after surface conditioning before rebonding. The shear bond strength with each group was tested. STATISTICAL ANALYSIS USED: One-way analysis of variance, post-hoc Scheffe multiple comparison tests. RESULTS: The results showed that sandblasting created more irregularities and deeper erosions while silica coating created superficial irregularities and shallow erosions.