Comparison of the kinetic frictional force between conventional plastic brackets with thermoplastic low-friction module ligation and self-ligating brackets.

AIM: To compare the kinetic frictional force of a conventional plastic preadjusted bracket with thermoplastic low-friction module ligation and a self-ligating bracket. MATERIALS AND METHODS: The testing model consisted of four 0.022-inch conventional plastic preadjusted brackets; four 0.022-inch self-ligating brackets for the first premolar, canine, and lateral and central incisors; and a 0.014-inch superelastic nickel-titanium and a 0.019 × 0.025-inch stainless steel wire. The brackets were either aligned for both wires or out of line by 0.5, 1.0, 1.5, and 2.0 mm for only the 0.014-inch superelastic wire. The wires were pulled for 3.0 mm at a speed of 0.1 mm per second. Unpaired t tests were used to compare the mean differences of the measurements between the two bracket systems with both wires. RESULTS: No significant difference in the kinetic frictional force between the two bracket systems and the two wires were found for the 0.014-inch superelastic wire at 0-mm deflection. CONCLUSION: Both bracket systems demonstrate low friction, which is beneficial for effective orthodontic tooth movement with light forces.

Frictional resistance in plastic preadjusted brackets ligated with low-friction and conventional elastomeric ligatures.

OBJECTIVE: To compare frictional resistance of the plastic preadjusted brackets ligated with the low-friction ligatures with those of the conventional elastomeric ligatures. DESIGN: In vitro study. SETTING: Department of Orthodontics, Faculty of Dentistry, Kyushu University, Fukuoka, Japan. MATERIALS AND METHODS: The testing model consisted of four 0.022-inch plastic preadjusted brackets for the first premolar, the canine, the lateral incisor, and the central incisor. A superelastic nickel-titanium 0.014-inch wire and a stainless steel 0.019 x 0.025-inch wire were used for this test. The brackets were either aligned or out of line by 0.5, 1.0, 1.5 and 2.0 mm for the 0.014-inch wire and aligned for the 0.019 x 0.025-inch wire. The frictional forces in plastic preadjusted brackets with low-friction ligatures and conventional elastomeric ligatures were measured at a pulling speed of 0.1 mm/second. Welch t-tests were used to compare the mean differences of each testing measurement between the low-friction and the conventional elastomeric ligatures. RESULTS: In both use of the superelastic nickel-titanium 0.014-inch wire and the stainless steel 0.019 x 0.025-inch wire, the brackets with the low-friction ligatures showed significantly lower frictional forces than those of the conventional elastomeric ligatures in both aligned and all misaligned brackets (P < 0.0001). CONCLUSION: The study found the significantly lower frictional forces for the low-friction ligatures than those of the conventional elastomeric ligatures.

Facial onset sensory and motor neuronopathy (FOSMN) syndrome responding to immunotherapies.

We report the first non-Caucasian case of facial onset sensory and motor neuronopathy (FOSMN) syndrome partially responding to various immunotherapies. A 55-year-old man had first felt paresthesia on his right cheek at age 45. This gradually extended to the scalp. Paresthesia of bilateral fingers and dysphagia appeared 6 years later. On admission, facial sensory impairment and bulbar palsy were found. There were no sensory or motor deficits evident in any limb, except for decreased deep tendon reflex and vibratory sensation. Videofluorography (VF) revealed decreased pharyngeal clearance. The sensory nerve action potential (SNAP) amplitudes of median and ulnar nerves were decreased. Intravenous immunoglobulin therapy and plasma exchange ameliorated his dysesthesia and dysphagia after several weeks, and resulted in improvements in VF and SNAP abnormalities. These observations suggest that FOSMN syndrome maybe, in part, immune-mediated.