Asociación Mexicana de Ortopedia Maxilar A.C.
Asociación Mexicana de ortopedia Maxilar, A.C.
9a Reunión Anual AMOM. 24-28 de Noviembre del 2004.
Cancún, Quintana Roo. México.
FIXED APPLIANCES - SUPERELASTIC WIRE MATIRIALS AND HOW TO USE THEM
Innovations in orthodontic materials have brought tremendous positive changes to the field of orthodontics . Treatment quality , speed of treatment , patient comfort, and ease of application have all been improved . However, to fully utilize the potential of such materials optimally and to avert negative effects, and understanding of the principles and special behavior of these materials is necessary.
It is discussed how the wire forces related to problems such as pain and root resorption. Then some basic thoughts about force generation in wires are presented and the differences between classic an superelastic wires is explained . Then thermal properties of superelastic wires and their influence on the treatment are shown. Then methods to measure the forces and compare different wires are developed and many commercially available wires are tested , the results evaluated and compared .
It shows that large differences in the acting force exist between wires is the only possibility to limit the forces of superelastic archwires .
The clinical application of superelastic wires differs that of conventional materials. Methods to shape these wires using special pliers are shown and a correct and efficient method to ligate them using steel ligatures are presented . It is surprising how the acting force of these wires is influenced by the way and by the order that the archwire is guided into the bracket slots .
A number of cases in which superelastic wires were applied to their best performance are shown and it is explained why the superelastic wires were of advantage in these cases . Last not least the possible benefits for doctor and patient will be explained .
Aparatos de Retención 1
RETENTION 1.- BONDED LINGUAL RETEINERS, CONCEPT, CLINICAL STUDIES
Several studies have shown the importance of efficient retention , especially but not limited to the treatment of adults patients . Retention needs to be efficient and reliable, should be esthetic , must not increase the risk of caries, and needs to be adjusted to the compliance of the patient. Bonded retainers are in many cases by far the appliance best suited for the task.
A concept of long-term fixed retention is presented that is attractive to both patient and doctor. We use almost exclusively multi-stranded wires of small diameters to assure maximum individual tooth movement and minimal risk of breakage . To improve biocompatibility in permanent retention we have been using multi-stranded retainer wires made of both gold and titanium for all numbers of years . Some of these products are now available commercially . We have also used fiber-reinforced composite retainers and will elaborate on these experiences an also on recently introduced new materials from pre-impregnated fibers.
More important than the material are the technique and the usage protocol . It is especially important to place the retainers immediately at debonding of the brackets . The design of the retainer and the bonding to the enamel surface is important to oral hygiene and answers are given to questions regarding these problems.
To get an idea of the long-term reliability of these retainers a retrospective study was carried out regarding any problems with the retainers even years after placement. The results show that bonded retainers are rather reliable and in the study they had a mean time between failures
(MTBF) of over 2 years .
Hints are given how to correct minor irregularities that might have appeared in cases where the retainer got loose . And last not least applications are shown where retainers are used as a part of active appliances to decrease the cost and discomfort for the patient.
FIXED APPLIANCES 2. MODERN ESTETIC BRACKETS AND BONDING METHODS
This lecture will cover the latest information about ceramic brackets and modern bonding techniques . Ceramic brackets have been on the market for more than 10 years to fulfill the demands of both patients and doctors for a more esthetic appliance in comparison to metal braces . The first generations of ceramic brackets gave a lot of trouble to the orthodontist who held responsible for the enamel damage that sometimes occurred during the removal of the braces which was something only possible with the help of a diamond bur and a lot of time and patience . In vitro studies even revealed another disadvantage of ceramic braces which turned out to produce a lot more friction between the orthodontic archwire and the slot which will probably increase treatment time.
Ceramic brackets are still more prone to facture and therefore special measure are to be used during the orthodontic treatment . The benefit of an esthetic bracket can be badly impaired by the use of elastic ligatures as they tend to discolor and there ruin the nearly invisible appearance of the braces . Alternative ways of ligating will be demonstrated and more esthetics auxiliaries will be shown and discussed .
To reduce the number of brackets to be repositioned during the treatment it is recommended to use light-curing adhesives to bond the brackets in the perfect position on the first go . This goal is much easier to achieve when there is sufficient time for positioning the brackets on the teeth . With light-curing adhesives there is enough time for the doctor to find the perfect position during bonding . Light-curing can be done with conventional light-curing devices, plasma lights or LED lights – they all provide a reliable bond strength on command allow immediate ligating .
Dr. Ibe will introduce scientific results concerning curing times and bond strength of the different light curing devices and will give clinical recommendations which system is the most easily used .
One of the most recently introduced products for “single handed” bonding are so-called “Self-etching-primers” containing a combination of etching and bonding in one single stage. These systems reduce the steps during bracket-bonding again und are much more convenient for us and our patients .
Aparatos de Retención 2
RETENTION 2. MODERN RETENCION APPLIANCES AND EXXIX RETAINER
This lecture will cover the way of using a tooth positioning appliance “positioner ”for finishing purposes and the vacuum-formed Essix retainer as a standard retention device for the orthodontic patient.
After a successful treatment with fixed appliances there are sometime little treatment goals that are not yet reached due to several reasons .Either the patient’s compliance was already decreased or the finishing phase was not as successful as we would have liked it or we have to remove the fixed appliance because the kids develop puberty and use their toothbrush not as much necessary .
We shall have a look at the laboratory procedure and steps necessary to manufacture a positioner out of thermoplastic material .
Even after a successful treatment there is no better retention appliance to influence the vertical dimension which means that every patient who had an open bite prior to treatment receives positioner to increase and stabilize the achieved overbite .
Clinical recommendations will be given what sort of tooth movement is possible , how to wear the “positioner” and what kind of problems can occur during the treatment .Alternative usage of the same material will be shown.
The second part of this lecture is dealing with the vacuum-formed so called Essix-Retainer which nowadays are an essential part of the busy praxis
Published by John Sheridam more than 10 years ago these very esthetic retention appliances are on the advance especially in treatment of adult patients. With the worldwide advertisement campaign of invisalign the acceptance for a splint-like retention increased even more.
Dr. Ibe shows the manufacturing of Essix like retainers and will give clinical recommendations for the long-term retention for the patient will be discussed .