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Removable Orthodontic Appliances

Orthodontics is a specialized branch of dentistry, and it involves the treatment, prevention and diagnosis of various dental problems. To correct some of these issues, a patient can be given a fixed or removable orthodontic appliance.

Removable Orthodontic Appliances


Introduction: The primary aims of this systematic review were to assess objective levels of wear of removable orthodontic appliances and components vs both stipulated and self-reported levels. We also aimed to consider patient experiences and the effectiveness of interventions geared at enhancing compliance.

Conclusions: Compliance with removable orthodontic appliances and adjuncts is suboptimal, and patients routinely overestimate duration of wear. Techniques for improving compliance have promise but require further evaluation in high-level research.

Results: There was high individual variation in most measured variables and in all groups/subgroups. During a median observation period of 186 days (range, 55-318 days) the actual wear time was 9.0 h/d (range, 0.0-16.0 h/d) and did not differ between distinct prescriptions (P = .49). Eight patients wore their appliances less than 2 h/d, and six of them did not wear their appliances at all. Overall, the median wear per day relative to prescription was 62.5% (range, 0.0-89.3%) for the 14 h/d and 112.5% (range, 0.0-200.0%) for the 8 h/d prescription wear (P = .01) groups. There was a strong negative correlation of age (median: 12.5 years) with the daily percentage of actual wear time per day relative to wear prescription (14 h/d prescription: n = 21, rho = -0.61, P = .00; 8 h/d prescription: n = 24, rho = -0.73, P = .00), while sex did not exert a significant influence on compliance (P = .58).

Conclusions: Despite the fact that patients and parents were informed about wear time recording, compliance was insufficient with regard to functional treatment (14 h/d prescription), while it was sufficient for retention purposes (8 h/d prescription). Objective measures are necessary to assess compliance with removable orthodontic appliances since patient compliance is a highly variable issue.

Introduction: The purpose of this study was to describe the movement of teeth adjacent to premolar extraction spaces during space closure with aligner appliances and then fixed appliances.

Methods: The sample included 24 subjects from a larger study investigating an aligner system. All subjects had at least 1 premolar extracted as part of treatment. Dental casts and panoramic radiographs were measured for tooth tipping adjacent to extraction spaces at 3 treatment points: T0, initial; T2, end of aligners; and T3, end of fixed appliances. Chart records were reviewed for information about time in treatment.

Results: Treatment with aligners resulted in significant tipping of the teeth adjacent to premolar extraction sites. When followed by fixed appliances, these teeth were significantly uprighted. Aligner treatment followed by treatment with fixed appliances took an average of 40 months.

Conclusions: In premolar extraction patients treated with aligners, dental tipping occurs but can be corrected with fixed appliances. This dual modality treatment might require more time than treatment with fixed appliances alone.

Recent advances in technology have led to the availability of sequential removable orthodontic appliances (aligners) to move teeth in a stepwise fashion (Invisalign, Align Technology, Santa Clara, Calif). This study was undertaken to compare 2 distinctly different materials (hard and soft) and 2 activation frequencies (1 week and 2 weeks) for this technique. Fifty-one subjects, stratified by peer assessment rating (PAR) and need for extractions, were randomly assigned to a hard or a soft plastic appliance, and a 1-week or 2-week activation time. The primary endpoint was the completion of the initially prescribed series of aligners. Changing aligners every other week was more likely to lead to completion of the initial series of aligners than changing aligners weekly (37% vs 21%). No substantial difference in the completion rate was observed for the soft versus the hard appliance (27% vs. 32%). The completion rate was highest (46%) among patients with PAR scores less than 15 and no planned extractions, and lowest (0%) among subjects who had 2 or more premolars extracted. All who completed their initial series of aligners required an additional series of aligners or fixed appliances to achieve the original treatment goals. This exploratory study suggests that subjects with a 2-week activation regimen, no extractions, and a low PAR score are more likely to complete their initial series of aligners.

This is a comprehensive list of functional appliances that are used in the field of orthodontics. The functional appliances can be divided into fixed and removable. The fixed functional appliances have to be bonded to the teeth by an orthodontist. A removable functional appliance does not need to be bonded on the teeth and can be removed by the patient. A removable appliance is usually used by patients who have high degree of compliance with their orthodontic treatment. Fixed appliances are able to produce very accurate movement in the teeth [1]

In the Anterior-Posterior dimension, appliances such as Class II and Class III are used. Appliances used in transverse dimension are utilized to expand either the maxillary or the mandibular arch. Appliances used in the vertical dimension are used to correct open or deep bite.[2][3]

It is important to note that initially dento-facial Orthopaedics was mainly done in Europe. The United States was introduced to Fixed Orthodontics by Edward Angle. Norman William Kingsley was the first person to show "jumping the bite" by using an anterior bite plate. Hotz then developed the Vorbissplate which was a modification of Kingsley's plate. Wilhelm Roux is credited with being the first person who studied the effects of functional forces on Orthodontics in 1883. His workings were then used by other dentists studying dental orthopaedics. His teachings became known as Roux Hypothesis, which Karl Haupl later expanded upon. The Monobloc was developed by Pierre Robin (surgeon) in 1902 and is considered to be one of the first functional appliances in Orthodontics. The Monobloc was a modification of Ottolengui's removable plate. In 1908, Viggo Andersen developed the Activator appliance. This was the first functional appliance to be widely accepted, especially in Europe. This appliance became the "Norwegian" system of treatment in Orthodontics in the early 1900s.[citation needed]

In addition, in 1905 the Herbst Appliance was introduced by Emil Herbst. This appliance did not go through much evolution until the 1970s when Hans Pancherz revived interest in it. In the 1950s, Wilhem Balters modified Andersen's Activator appliance and gave the new appliance the name Bionator Appliance, which was designed to produce forward positioning of the mandible. The Positioner Appliance was developed by Harold Kesling in 1944 in order to aid the orthodontic treatment during the finishing stage. The Frankel appliance were developed by Rolf Frankel in 1957 for treatment of Class I, II, III Malocclusions . William Clark also developed Twin Block Appliance in 1978 which resembled Artur Martin Schwarz double plates that he developed in the 1950s.[citation needed]

Some of the components of removal appliances are retentive in nature. They are usually connecting by an acrylic component known as baseplate. The majority of the appliances include components such as Labial Bow and Adams Clasp, both of these components are passive in nature. Labial bow is a wire attached to the baseplate which goes around the incisor teeth to provide retention of those teeth. Labial bow usually have U-Loops at the end to allow it to activate more. Adams clasps are used for retention of these removable appliances and are usually fabricated in the molar areas. They are usually manufactured from 0.7mm hard stainless steel wire (HSSW), or 0.6mm HSSW when planned for deciduous teeth.[4] Removal of the appliance is usually performed by holding the bridge of this clasp. Other clasps that are usually used are C clasps on canines, Southend Clasp (on anteriors),[5] Ball-ended clasp (primarily for use with the Twin Block system in the lower anteriors)[6] and Plint clasp.

Active components of removable appliances include springs which provides light forces on a tooth to move it orthodontically. Components such as Palatal Finger Springs, Buccal Canine Retractor, Z-Spring, T-Spring, Coffin Spring, Active Labial Bows (Mill's Bow or Roberts retractor), Screws and Elastics are all considered to be active components of the removable functional appliances. If a spring is moving one tooth it is made of 0.5mm thick stainless steel wire. The thickness increases to 0.6 or 0.7mm wire if it is to move more teeth or a larger/multi rooted tooth.[7]

Subjects and methods: Consecutive recruitment of 64 patients who met the following inclusion criteria: early to late mixed dentition, anterior crossbite with functional shift, moderate space deficiency in the maxilla, i.e. up to 4mm, a non-extraction treatment plan, the ANB angle > 0 degree, and no previous orthodontic treatment. Sixty-two patients agreed to participate. The study was designed as a randomized controlled trial with two parallel arms. After written consent was obtained, the patients were randomized, in blocks of 10, for treatment either with a removable appliance with protruding springs or a fixed appliance with multi-brackets. The main outcome measures assessed were success rate, duration of treatment, and changes in overjet, overbite, and arch length. The results were also analysed on an intention-to-treat basis.

Results: The crossbite was successfully corrected in all patients in the fixed appliance group and all except one in the removable appliance group. The average duration of treatment was significantly less, 1.4 months, for the fixed appliance group (P 041b061a72


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