Role of the Friction Free Distalize Appliance (2FDA)Pat in the Molar Distalization: Photoelastic Analysis and Alkaline-Phosphatase (ALP) Activity on First Molar and Bicuspid

Abstract

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This study describes the effects of one particular molar distalizing appliance, the Friction Free Distalize Appliance (2FDA), in a sample of 20 consecutively treated and growing patients to verify the osteoblastic activity in the compression and traction sites of both the molars and the bicuspids when used as the anchorage teeth. The 2FDA appliances were constructed utilizing a Nickel Titanium open coil spring of 200 gr force in order to distalize the maxillary first molar. The reaction force was controlled utilizing the principle of low/free friction. The results show that the resin around the root of the bicuspid did not discolour at all, which indicates an absence of a force load. On the other hand, on the molar, the resin around the root of the molar became discoloured due to the fact that an orthodontic force was involved with the tooth. To better understand whether the quantity offorce that reached the tooth was able to produce osteoblastic recruitment in the sites of tension of the molar and the bicuspid, we quantified an enzyme, the alkaline phosphatase (ALP), present. This measurement allowed us to verify a regular increase of the ALP on the site of molar traction. We also elaborated a mathematical model to evaluate the quantity of force of reaction that produces the device on the bicuspid. Such force results as being 8.34 grams which equals half the pressure of the capillaries of the parodontal ligament (18 grams). The 2FDA appliance compares favourably with other intra-oral distalization devices for the resolution of patients with Class II malocclusions, and is the only distalizing appliance that does not determine osteoclastic/osteoblastic recruitment on the "anchorage tooth".Class II malocclusion cases constitute a heterogeneous teeth, proinclination ofmaxillary incisors and produce some group of patients that represents a significant portion of all distal tipping ofthe maxillary molars. (24-27). International the patients who attend for orthodontic treatment. Class literature (28-36) reports a loss of anchorage between 15 II malocclusion is not a single clinical anomaly. It can and 65%; a molar tipping between -2.2°and 16.0°; and a occur in various forms. In non-extraction Class II adult bicuspid tipping between _4.3°and 2.4°. patients, maxillary molar distalization may be used to To try to minimize the adverse effects of the molar correct the molar relationship and to alleviate crowding distalization with a non-compliance device, we recently in the maxillary arch. A variety of techniques for molar developed a new distalize appliance named Friction Free distalization have been suggested, including those that Distalize Appliance (2FDAPal). It has been proven that this require patient compliance (1-10) and those that reduce new device can distalize maxillary molars with very few the need for patient co-operation. In a survey by Sinclair or, in several cases, without the disadvantages ofthe ot...

Influence of flowable resins on the shear bond strength of orthodontic brackets

“…Moreover, TF and GF showed slightly higher SBS values than XT. Based on published literature, many researches had achieved similar or better SBS values using flowable resins as the adhesive compared with the conventional Transbond XT adhesive [7][8][9] . On the efficacy of using flowable resins to bond orthodontic brackets to teeth, there are advantages and disadvantages due to their flowable nature.…”

“…To date, many commercial adhesives are constituted of these components through co-mixtures of monomers and by changing the filler content [3][4][5][6][7][8][9] . To enhance workability, diluents of low molecular weights such as TEGDMA and/or UDMA were usually added.…”

“…In the orthodontic literature, there are contradictory reports on the shear bond strength (SBS) of flowable resins compared to the conventional Transbond XT 8,9) . The bracket bond strength result of an adhesive is influenced by several factors.…”