Laboratory Techniques In Lingual Orthodontics

If the brackets are not well positioned before the orthodontic treatment it's obvious that the treatment time will increase and the final results may not be satisfactory. Because of the difficulty in access and wide anatomical variation of the lingual surfaces of the teeth it is not possible to place the lingual brackets on their ideal positions. These conditions makes indirect bonding an essential procedure for lingual orthodontics. In this review the laboratory procedures where the lingual brackets are placed on the original or on the duplicated set-up dental models are summarized

Clear Aligner Appliances: Fabrication and Clinical Application

The Clear Aligner can be used to solve a minor tooth movement case and orthodontic relapse problems after treatment. It is a simple and low cost appliance which can be used by both orthodontists and general dentists. It works quickly and is comfortable for most patients. The Clear Aligner uses plastic sheets of various thickness levels. Plastic sheets are used along with a vacuum former. A set-up model is used with progressive movement of the teeth, which are positioned to ideal position. The Clear Aligner should be replaced every three weeks with a new impression taken at each visit. The Clear Aligner can carry out minor tooth movement with no brackets bonded to the teeth. Minor tooth movement including crowding resolution, space closure, arch expansion/constriction, relapsed cases, intrusion/extrusion, eruption guidance, and detailing could be done by the Clear Aligner

3D FEM comparison of lingual and labial orthodontics in en masse retraction

BACKGROUND: The aim of this study was to compare displacements and stress after en masse retraction of mandibular dentition with lingual and labial orthodontics using three-dimensional (3D) finite element models (FEM).METHODS: A 3D FEM of each lower tooth was constructed and located as appropriate to Roth's prescription. The 0.018-in. GAC Roth Ovation labial and Ormco 7th Generation lingual brackets were virtually bonded to the lower teeth and threaded with 0.018 × 0.025- and 0.016 × 0.022-in. SS labial (Tru-Arch form, small size) and lingual (mushroom) archwires. En masse retraction was simulated by applying 300 g of distal force from the canine to the second premolar on the 0.016 × 0.022-in. SS labial and lingual archwires. The type of finite element used in the analysis was an eight-noded brick element. The Algor program (Algor Inc., Pittsburgh, PA, USA) was used to calculate the strains and displacements at each nodal point.RESULTS: Lingual tipping and extrusion of the anterior dentition occurred with both archwires. At the premolars and first molars, intrusion, lingual movements, and lingual tipping were seen with the labial archwire, while intrusion was accompanied by labial movements, mesial tipping, and buccal rotation with lingual mechanics.CONCLUSIONS: Lingual vs. labial bracket placement influences the pattern of tooth movement, but the stress that occurs around the teeth can be accurately mapped using a 3D FEM model