ABSTRACT
AIM: The purpose of this study was to evaluate morphological and biomechanical characteristics of a commercial mini-implant. METHODS: Orthodontic low head mini implants, in the two available sizes of 1.5 and 2 mm, have been used. The electronic scanning microscope evaluation has been tested on 3 groups each one composed of 4 samples, observed in numerous enlargements and in the three dimensions of the space. The groups were composed of new mini implants, undamaged mini implants observed after their clinical use and mini-implants broken at the moment of their insertion or removal after their therapeutical use. RESULTS: The microscope analysis of unused mini implants has shown how the diameter reduction of the neck represents the area of greater weakness; such parameter is very important in determining screw resistance to fracture. In fact the fracture observed in vivo always happened to this degree. Some micro carvings and cracks were shown on the surface, these irregularities could facilitate or promote the enlargement of the cracking itself. CONCLUSION: From the results obtained it is clear that the steel is adequate for permanence in the oral cavity, and moreover the material itself is adapted to bear the pressure put on it during therapy. However, it remains advisable to make certain changes to better the surface and geometry of the miniscrews.
Subject(s)
Bone Screws , Orthodontic Anchorage Procedures/instrumentation , Device Removal , Equipment Design , Equipment Failure , Fractals , Humans , Materials Testing , Maxilla , Microscopy, Electron, Scanning , Shear Strength , Stainless Steel , Surface PropertiesABSTRACT
The maintaining of the space during mixed dentition, allows the patient to obtain a good occlusion, the right growth and facial development. The orthodontist can preserve the space, using simple appliances like the lip bumper and the lingual arch.
Subject(s)
Dentition, Mixed , Orthodontics, Interceptive , Space Maintenance, Orthodontic , Child , Humans , Malocclusion/prevention & control , Orthodontic AppliancesABSTRACT
The study of two cases of ultrasound prenatal diagnosis of cleft lip and palate and cleft lip, led the Authors to suggest the usefulness of first istance precocius correttive surgery in the immediate postnatal period. This correttive surgery not only allows the infant to be fed by natural vias, but it also facilitates the coordinated programming of successive final correttive surgeries by the plastic, the maxillofacial surgeons and the orthodontist.
