ABSTRACT
Over the last decade magnets have been used in orthodontic and dentofacial orthopaedics and attempts have been made to evaluate the biological implications of magnets and magnetic fields during clinical application. This review aims to indicate the advantages and disadvantages of magnets in orthodontics and dentofacial orthopaedics over traditional techniques, and update related clinical experiences. The treatment of impacted teeth and Class II malocclusions by means of magnetic force is favoured and the correction of Class III and open bite malocclusions involving the use of magnets also appears promising. The advantages of magnets over traditional force delivery systems are: frictionless mechanics, when the magnets are in attractive configuration; predictable force levels, no force decay over time and less patient co-operation. However, the size of the magnets can increase the bulk of the appliance and three-dimensional control is limited when the magnets are in a repulsive configuration. In addition magnets used in vivo require a coating to prevent corrosion and the possible side effects of corrosive products.
Subject(s)
Magnetics , Orthodontic Appliances , Animals , Biocompatible Materials , Cells, Cultured , Corrosion , Electromagnetic Fields , Humans , Malocclusion/therapy , Orthodontics, Corrective/instrumentation , Palatal Expansion Technique/instrumentation , Tooth Movement Techniques/instrumentationABSTRACT
A clinical study was recently undertaken to evaluate the dental and skeletal effects of the pendulum appliance (PA). In the present study, the appliance was modified by incorporating an uprighting bend into the distalizing spring during the second phase of treatment to avoid excessive distal tipping of the maxillary molars. The sample consisted of 20 patients: 8 females and 12 males, mean age 13.11 +/- 1.10 years. Eight of the patients were subjected to a slow rate of maxillary expansion. Measurements were obtained from cephalometric headfilms prior to (T1) and the day of removal (T2) of the PA. Treatment changes were analyzed and compared with the previous study. The PA with uprighting bends led to reduced molar tipping without significantly changing the effects of the PA, with the exceptions of 0.62 mm more anchorage loss of the maxillary incisor edge and increased treatment time. There was no significant difference in anchorage loss between the patients with and without maxillary expansion.
Subject(s)
Malocclusion, Angle Class II/therapy , Molar , Orthodontic Appliances , Tooth Movement Techniques/instrumentation , Tooth Root , Adolescent , Cephalometry , Child , Female , Humans , Male , Maxilla , Orthodontic Appliance Design , Palatal Expansion Technique , Time Factors , Tooth Migration/etiology , Tooth Migration/prevention & control , Tooth Movement Techniques/adverse effectsABSTRACT
The purpose of the present study was to evaluate the healing pattern of an experimentally induced osteotomy in Hartley guinea pigs in the presence of static magnetic and pulsed electromagnetic fields. The sample consisted of 30 Hartley guinea pigs 2 weeks of age divided into 3 groups: pulsed electromagnetic, static magnetic, and control. An osteotomy was performed in the mandibular postgonial area in all groups under general anesthesia. During the experimental period of 9 days, the animals were kept in experiment cages 8 hours per day, the first two groups being in the presence of pulsed electromagnetic and static magnetic field, respectively. Based on histologic results, both static and pulsed electromagnetic fields seemed to accelerate the rate of bone repair when compared to the control group. The osteotomy sites in the control animals consisted of connective tissue, while new bone had filled the osteotomy areas in both magnetic field groups.
