commonly used retainer

The biologic aims to be considered when choosing a retainer,are
- maintenance of periodontal support,
- maintenance of optimal oral hygiene and
- maintenance of functional forces on all the teeth.

Commonly Used Retainers
Removable Acrylic Retainers
These include Hawley retainers, wrap around retainers and Barrer retainers and are constructed from a wire framework and acrylic baseplate. They can be modified for active tooth movement by activating the labial bow or by incorporating springs. They are routinely worn full time for three to six months, part time for one year to 18 months, followed by continued wear twice a week.

Bonded Retainers
These fixed retainers are constructed from .0195” or .0175” multistrand stainless steel archwire. An indirect technique is used to adapt the wire passively to a working model. The retainer is attached to the lingual surface of the teeth using floss or a specially constructed jig and is bonded in position using a light-cured composite resin. Care should be taken to clear the occlusion during placement in the maxillary arch. Excess bond on the lingual surfaces and at the gingival margins should be carefully removed, and the area polished giving smooth even surfaces which are easy to clean

Positioners
Positioners are elastomeric or rubber removable retainers that are either preformed or custom made. Preformed positioners are available for bicuspid extraction cases and non-extraction cases. Sizes are determined by measuring the mesiodistal dimensions of the six anterior teeth. These preformed positioners cannot compensate for individual variation in the size of the teeth, arch width, arch form or tooth size discrepancies. For these reasons, they should only be used temporarily

Comparison Peer Assessment Rating Index and Index of Treatment Complexity, Outcome, and Need for Orthodontic Treatment Outcome

In order to quantify malocclusion, occlusal traits are often given a numerical weighting system and combined into mathematical expressions called occlusal indices. The most important advantage of using occlusal indices is to maximize consistency between and within examiners. The use of the pre- and post-treatment scores to derive an estimate of treatment improvement is familiar. Peer Assessment Rating Index (PAR index) has been developed to provide a single summary score for all the occlusal anomalies which may be found in a malocclusion. The score provides an estimate of how far a case deviates from normal alignment and occlusion. The difference in scores between the pre- and post-treatment cases reflects the degree of improvement and, therefore, the success of treatment. The Index of Treatment Complexity, Outcome, and Need (ICON) has relatively lower predictive accuracy for the treatment outcome than for treatment need judgements. This study showed correlation between PAR index and ICON with respect to outcome. Twenty patients were identified who had undergone removable appliance treatment within the Orthodontics Laboratory Dentistry Faculty Hang Tuah University. Patients were included in the study if they fulfilled the following criteria: undergone removable appliance 2 years, and pre- and post-treatment study models available.

TEMPORO MANDIBULAR DYSFUNCTION AND ORTHODONTICS

Teeth are extracted for several reason in orthodontics. The most common reason for extraction is the relief of crowding and to create space to gain good alignment of the teeth. When premolar teeth are extracted for orthodontic treatment this leads to temporomandibular dysfunction (TMD) because of over retracting the upper incisors during space closure, forcing the condyle into a posterior position. It is this posterior position of the condyle within the fossa, which is presumed to cause an anteriorly displaced disc and therefore TMD .The previous study of 42 patients with a Class II division 1 malocclusion treated by the extraction of both upper first premolars and fixed appliances, 70 % showed a forward movements of mandibular basal bone and the changes in condylar position
Orthodontic treatment is needed for those whose occlusion is not functionally optimal to prevent the development of TMD.

PROPHYLACTIC REMOVAL OF THIRD MOLARS IN ORTHODONTICS

Eruption of the third molar teeth representing completion in formation of entire tooth. But a lot of observer have a notion that, pressure eruption of the third molar will generate mesial pressure at tooth in front of its and can cause overcrowding. The influence of the third molar to anterior regio have been percieved by Scawarze in 1973. Mesial presure can influence efficacy of orthodontics treatment, this matter is can be seen from the sign of early return of crowding incicivus tooth after finishing treatment orthodontic. Repeal of profilaksis the third molar for the reason of orthodonti treatment have been sugested ( Andersen, 1935). Cases which have been evaluated to 500 patient, found that 22,6 % the third molar of maxilla and 22,5 % mandibula are axtracted in order to orthodontic treatment. The age suggested took a fancy is 14 - 16 year. Repealing of the tooth expected can discontinue presure to mesial is which still going on during period of child growth. Prevention of relapsing treatment resault orthodonti represent main reason for repealing of the tooth.

EXTRACTING SECOND MOLARS IN ORTHODONTICS TREATMENT

An important reason for elective extractions in orthodontics is the relief of crowding. First premolar teeth provide up to 14 mm of space for the relief crowding. Second molar teeth can provide some 18 – 22 mm of space, of which is made available to the relief of crowding in the lower labial segment where crowding most often occurs.
The advantages extracting second molar include, Less detrimental to facial profile, Facilitates the eruption of third molars, Spontaneous relief of crowding in the premolar region, Prevents crowding in a well aligned lower arch, Aids distal movement of the buccal segments with extra oral traction, Shorter treatment time, Finctional occlusion is better.
The ideal time for extracting second molars is when the third molar crown is fully formed and other claim should be extracted as soon as they erupt into the mouth.Several consideration need to be taken before extracting second molar, include radiological evaluation of third molar, should be present, have good size, shape and position.

THE EXTRACTION OF PRIMARY TEETH AS PART OF ORTHODONTICS TREATMENT

Extraction of a primary tooth it is often a dilemma whether to merely remove the unsaveable tooth, to extract a contralateral tooth from the same arch (balance) designed to minimize centerline shift, or to extract a tooth from the opposing arch ( compensation) designed to minimize occlusal interferance by allowing teeth to maintain occlusal relationships as they drift.
Early loss of one primary canine cause centerline shift.The more crowded the dentition, the more the need for balance extraction. Centrelines shift with complete space closure, delay balancing extraction until a full orthodontics assessment is made. Loss of a primary second molar, especially the second may allow mesial drift of the first permanent molar.There is no need to balance extraction because this will have no appreciable effect in centerlines . However this extraction may allow forward movement and tilting of the adjacent first permanent molar .Therefore consideration should be given a space maintainer