ORTHOPEDIC AND FUNCTIONAL APPLIANCES
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Proceedings of 16 the Campinas Dental International Conclave
ISSN 1678-1899 N. 115 - March / April 2005
REMOVABLE ORTHODONTIC, ORTHOPAEDIC AND FUNCTIONAL APPLIANCES COOKBOOK DEMONSTRATION
AUTHORS: JANISSE FARIA DE SILVA, VALERIA GASPAROTO F. DE FARIA
Introduction
There are a variety of techniques and philosophies to treat malocclusion. Orthodontics as a discipline includes Functional Orthodontics, Functional Orthopedics of the Maxillary/ mandibular (FOM), and also mechanical Orthodontics. Within this philosophy there are several ways to work. In Orthodontics we have braces and removable (ROA) while in Functional in Orthopedics we have the functional appliances (FOA).
The devices used in the orthodontic clinic are made by laboratory technicians. These are manufactured in a laboratory environment, away from the patient's mouth. Hence they must go through multiple adjustments and adaptations wit in the oral cavity. These are performed by the orthodontist.
This study is about the appliances that are made in the laboratory and their clinical outcomes. And precisely for this reason you need a perfect diagnosis to design of the device you want. Attaining proper design, is a key step for a perfect clinical adaptation.
All philosophies and techniques are aimed at better patient care. They are designed to maintain the normal development of occlusion or interfere with course of disharmony and restore the normal dental-facial development.
Concept of Removable Orthodontic Appliances (ROA)
The ROA are dental mucosal supported. In most devices the support base has the function of anchoring, support, and retention, and it also functions as an activator in some of these appliances. They are devices designed to interfere with malocclusions. In 1902, CA Hawley used the palatal removable appliance as a retainer for teeth that had been orthodonticly moved. Even today, Hawley’s palatal appliance has this use; however, many changes were introduced to make it an active plate.
These dysfunctions of the stomatognathic system can be normalized with the use of the ROA. Such success occurs when the clinician performs properly diagnosis, has a good knowledge of their Mechanical potentialities, and maintains control of their use and limitations. Hence, the lab technician must be familiar with basic subjects such as anatomy, histology, and neurophysiology. He must also have considerable experience.
Components of removable orthodontic appliances
•Base support
•Retentive Part
•Active part
The orthodontic wires make up the active part of the retentive and removable orthodontic appliances.
Base Support
This part is made of an acrylic resin, and not only keeps the different parts of the device connected, but also resists the forces released by the active part and the retaining clips when activated.
Retentive Part
It is composed of elements whose function is to keep the unit in the buccal or oral cavity. Clasps should distribute the active forces in the plate when it is in action.
The retention elements are:
• Retaining clasps
• Vestibular Arch Wire
• Acrylic
Active part
Consists of elements of an appliance that generate forces to move teeth. These are:
• Springs and orthodontic wires
• Screws
• Vestibular Arch Elastics
Materials for making AOR
Acrylic Resin
The resins are organic compounds consisting of an acrylic polymer resin (powder) and monomer (liquid), that in proportion polymerizes the resin and which will form the basis of support for the Functional Orthodontic Appliance and the Removable Orthodontic Appliance . The self-curing resins can be chemically activated or thermally activated.
Despite fact that heat-activated acrylic resins are better, the FOA and ROA are generally made with self curing resins, because they are temporary appliances. The self-curing resins are porous which means they absorb oral fluids that can cause mouth odors. In addition, they release the residual monomer and the patient might complain of an unpleasant taste. In contrast, the heat-activated resins require much more complex handling and more time working on its construction, which is not justified.
To reduce this porosity, the polymerization should be done in water under pressure. It is cured in a container with water from 25 to 30 pounds / square inch of pressure, between 40 ° to 50 ° C for 20 to 30 minutes.
Alloys
Stainless steel is the alloy most commonly used in orthodontics.
It is used for making pliers, bands, instruments, accessories for bonding and soldering, intraoral and extra oral appliances, and orthodontic wires for making springs and arches wires.
Orthodontic wires
It is the active part of orthodontic accessories. When tied to orthodontic accessories it releases forces that allow the movement of teeth within the alveolus (bone tissue). The mechanical characteristics of an orthodontic wire should promote a rapid movement of the teeth and reduce the biological cost. In other words, it should do so, without causing excessive pain, and without damaging the alveolar bone crest. It must be biocompatible, should not cause alveolar absorption. The steel used in orthodontics is the stainless 300 series, specifically the 304, which has in its composition 18% chromium, 8% nickel and 2% carbon. Chromium (17% to 25%) prevents oxidation in the oral environment. Nickel (8% to 25%) increases the hardness and helps prevent oxidation by the action of food and oral fluids.
Stainless steel has advantages that justify its stay in the labor market, it is low cost compared to gold, it also has good flexibility, biocompatibility, low surface friction due to the high polish, good formability, the possibility of making all types of folds, and also can be welded.
In orthodontic, clinical practices thinner gauges of wire are used. They are round, rectangular, and square. Round steel wires are used in the routine lab work to make springs, bows and clamps. These wires can be of various calibers: 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm and 1.2 mm.
According to the type of device that is being made different gauges of wire may be used.
Some indications for the manufacture of springs and clips are as follows:
• 0.6mm wire-clamps in gout; containment springs and lower fixed lingual digital.
• 0.7-mm wire clamps in gout; digital springs; vestibular arc plate and grid Hawley palate.
• Quadhelix-wire 0.8 mm; bihelix and unihelix.
• Wire 0.9 mm or 1.0 mm-clamp "C"; transpalatal bar; button Nance; lingual arch Nance; Quad; bihelix; or unihelix.
Working with stainless steel wire
It is very important that professionals develop, and dominate their manual dexterity. This requires training and discipline. To start bending manufactured components and FOA/ROA, it is necessary that the wires chosen be straight with no marks or irregularities, which can cause breaks. This is a classic error in the construction of parts(clasps etc) of an apparatus.
Grip the wire and clamp it with the pliers for support. The thumb rests on top of the wire and the index and middle fingers rest on the Bottom. Make moves against the pressure boundary.
Pliers
There is a variety of orthodontic pliers. They are highly specialized instruments that need to be known for the practice of orthodontics.
The most used for constructing ROA/FOA are:
Pliers 139 – Used to work with any type of wire, it has a tapered end and a pyramidal edge , these allow the technician to produce rounded angles.
Dela Rosa pliers - Used for contour caliber wireless in devices such as the lingual arch Nance and the transpalatal bar
Half Cana Clamp- 034mxc- Used to work with caliber wires enabling the production of some bends.
Cutting Pliers - Used to cut the ends of the wires.
Removable Orthodontic Appliances
Removable braces can correct the position of some individual teeth or a group of teeth or an entire arch, and normalize a malocclusion restoring the normal function of the stomatognathic system.
Construction:
Base Support
In most devices, the support base has the function of anchorage, support and retention ,and in some cases plays an active role. The ROA are dental- mucosa-supported, they use the teeth, palate and muscles as anchorage.
Limits of the support base: In the maxilla, is limited in the posterior region, distal to the first or second molars. Anterior and lateral sufaces remain palatal to all teeth. In the lower jaw, the base extends to the depth of the lingual groove and should be thicker to prevent fractures.
Types of Removable Orthodontic Appliances:
Hawley’s Board: It is indicated as a retainer after moving teeth with braces.
Class I with vestibule version of incisive.
Expansion Plate, suitable for unwinding of unilateral or bilateral posterior cross-bite.
Lingual plate with a grid. The top plate may have an aggregate of acrylic and steel wire in the palate. This is for the treatment of lingual dysfunctions in cases of anterior open bite. (picture)
Functional appliances
The functional orthopedist diagnoses and treats the problems of growth and development that affect the dental arches and their bases. Treatment targets the restoration of harmony in the neuromuscular system, restoring the normal oral functions that have been altered in malocclusion. Such treatment uses the natural forces originating from the proper function of muscles.
Objective: 1 to remove unwanted interference during growth and physiologic development.
2 act directly on the neuromuscular system that governs the development of the jaw bone. This will make the teeth occupy their functional and aesthetic places. Acting in this way, the jaw acquires new postural reflexes. This is another dynamic which produces a harmonic balance within the neuromuscular envelop. This improves chewing efficiency, and leads a healthier digestive system.
Construction:
After the bite registration is mounted, changes in posture considered, you begin to build the components of FOA, which are the springs and arches.
Front springs - Pairs parts, constructed with 0.8 mm wire A and B two elbows built in different planes and the C curve measuring approximately 2 – 3mm between the 2 wires.
Borders: depends on the desired action. Retention: should be reinforced.
Vestibular arch- single piece made with 0.9 mm wire.
Borders and position: reach to the distal of second premolar or deciduous molar. The space between the curve and the wire must have 3mm and be on the same plain.
Retention: retention should be a 1cm bend placed in a position superior to the front springs.
Dorsal Arcos- pair parts made in wire 0.9 mm, called lower conduction.
Borders and position: follows straight from the most distal portion of the last lower tooth in the direction of the laps. (Ref 5)
Screws - often are located further forward and as deep as possible between premolars and molars.
Acrylic-base - Limit of the support base: In the maxilla, is limited in the posterior region, distal to the first or second molars, the anterior and lateral edges lie on the palatal surfaces of all teeth. In the lower jaw, the base extends to the depth of the lingual groove and should be thicker to prevent fractures
.
Planas’ Appliance: Professor Pedro Planas idealized the FOA Planas.
Indirect clues Simple Plan (PIPS).
These are indicated for finishing cases.
Indirect Track Planas Composite (PIPC). Multiple action devices are built with arches supported by indirect clues linking the dorsal part top to bottom, which acts as reinforcement to maintain posture. Indicated when the change of altitude is very large.
Simões Network; devices created by Dr. Wilma Alexandre Simões, who uses a chain of systems operating as a unit. Also to minimize the difficulties presented by other devices in a given period of growth. They can be:
Bioplastics: they are hard devices, SN1-SN7
Bioelástics-SN2, SN3 and SN6
Network Simões 1; SN1
Used to neutroclusion and distoclusion and never mesioclusion. When the incisors do not erupt enough, put in a Bimler appliance. At the time of eruption of second molars they are ready for placement. Clinicians must provide keys to turn them.
Simões Network 2; SN2
The appliance stimulates a change in posture of the tongue, raising its leading edge up. Also suitable for square jaw.
Simões Network 3; SN3
Bimaxillary protrusion or open bite, especially when there is divergence of the occlusal planes. It operates in transverse development, and offers control of the anterior region.
Bibliographical references
1. MAIA, FA Preventive and interceptive orthodontics, Practical Manual, 1st edition, São Paulo, Santos, 2000.
2. CABRERA, Operating CAGet al Orthodontics, Curitiba, Interactive Ltd., 2000.
3. GROHMANN, U. Aparatologia in Orthodontics, Dentofacial Orthopedics and Orthopedics-Functional Illustrated Atlas, São Paulo, Santos, 2003.
4. FLAT, P. Rehabilitación Neuro-occlusal (RNO), second edition, Barcelona, Masson-Salvat, 1994.
5. Simões, of Functional Jaw Orthopedics WA-Through Neuro-Occlusal Rehabilitation, Volume 2, 3rd edition, New York, Medina Arts, 2003.
