Effect of tooth displacement and vibration on frictional force and stick-slip phenomenon in conventional brackets: a preliminary in vitro mechanical analysis

Abstract

SummaryObjective: To evaluate the effects of tooth displacement and vibration on frictional force and stickslip phenomenon (SSP) when conventional brackets were used with a levelling/alignment wire. Materials and Methods:The samples consisted of six groups (n = 10 per group) with combinations of tooth displacement (2 mm lingual displacement [LD], 2 mm gingival displacement [GD], and no displacement [control]) and vibration conditions (absence and presence at 30 Hz and 0.25 N). A stereolithographically made typodont system was used with conventional brackets and elastomeric ligatures. After application of artificial saliva, static/kinetic frictional forces (SFF/KFF) and frequency/amplitude of SSP were measured while drawing a 0.018-inch copper nickel-titanium (Cu-NiTi) archwire at a speed of 0.5 mm/min for 5 minutes at 36.5 degree celsius. Two-way analysis of variance and independent t-test were performed. Results: Tooth displacement increased SFF and KFF (control < LD < GD, all P < 0.001) and reduced SSP frequency (control > [LD, GD], P < 0.01). Vibration reduced SFF, KFF, and SSP amplitude in the control group (P < 0.05, P < 0.05, and P < 0.001, respectively), but not in the LD and GD groups. SSP frequency was increased by vibration in the control, LD, and GD groups (all P < 0.001), and it was lower in the LD and GD groups than in the control group (P < 0.01). Conclusions: When conventional brackets and a 0.018-inch Cu-NiTi archwire were used in the tooth displacement conditions (LD and GD), vibration did not significantly reduce SFF, KFF, or SSP amplitude.

Frictional property comparisons of conventional and self-ligating lingual brackets according to tooth displacement during initial leveling and alignment: an in vitro mechanical study

“…In this study, a stereolithographic typodont system used in previous studies 12 17 18 was refabricated. This typodont system had a full maxillary dentition fixed to an archshaped metal frame, which allowed each tooth to move in the occluso-gingival (up and down) and labio-palatal (forward and backward) directions.…”

“…Each tooth had its periodontal ligament space filled with Imprint™ II Garant™ Light Body Vinyl Polysiloxane Impression Material (3M ESPE, Seefeld, Germany), which emulates the mobility of human teeth and absorbs mechanical stress. 12 17 18 …”

“…Although numerous studies have investigated the implications of friction between conventional labial brackets and archwires, 11 12 15 16 17 18 information about the frictional properties of lingual brackets is still limited, and some drawbacks exist in experimental design and methodology. For example, one or several lingual brackets aligned in a straight line have been used to measure frictional force.…”

Effect of passive self-ligating bracket placement on the posterior teeth on reduction of frictional force in sliding mechanics

“…Periotest (Siemens AG, Munich, Germany) revealed normal values in the mobility of the typodont teeth. 9 19 20 21 …”

“…For the CBs, after ligation with elastic modules (Unistick Ligatures; American Orthodontics, Sheboygan, WI, USA), a 3-minute waiting period allowed a reproducible amount of stress relaxation to occur. 5 9 19 22 24 …”