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At least 19 recordsLinked to original sources
PubMed1997

Bonded orthodontic retainers: the wire-composite interface.

The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. An in vitro model was developed to simulate the forces encountered at the wire/composite interface. No significant difference was detected between different multistrand wire types and diameters with regard to retention in composite. Wires were placed in one of three groups according to surface characteristics identified with scanning electron microscopy. Increasing the thickness of composite overlying the wire increased the force required to detach the wire from the composite. Thickness of composite greater than 1.0 mm overlying the wire may give little clinical advantage. Greater force was required to detach the wire from Concise Orthodontic (3M Unitek) than any other composite tested. In vitro abrasion resistance testing found Heliosit Orthodontic (Vivadent) and Right On (TP Orthodontics, Inc.) to have poor abrasion resistance, whereas Concise Orthodontic and Transbond (3M Unitek) had abrasion resistance comparable with restorative composites. Clinical recommendations are made based on these findings.

Adhesiveness↗
PubMed1991

On the design of looped orthodontic retainer wires.

Removable Hawley orthodontic retainers have long been prescribed by clinicians following completion of active therapy. Only minor changes have occurred in the design of the retainer over the past 40 years. Structural, in-service failures of this appliance are typically: 1) permanent (inelastic) deformation of the as-prepared labial bow from masticatory action that induces unwanted force transmitted by the appliance to the dentition; or 2) accumulated material damage from removal and replacement of the retainer that eventually results in fracture of the labial bow. This paper reports the results of a series of experimental studies; the overall objective was the optimization of the appliance design, focusing on the labial bow. Wire size, material, temper, canine-loop height, markings for bend placements, heat-treatment of the prepared bow, and two procedures for removing and replacing the appliance were investigated. The collective outcomes suggest a combination of design-parameter values to help maximize the life of the labial bow of the retainer.

Analysis of Variance↗
PubMed1995

Bonded orthodontic retainers: a review.

Recent reports have suggested that long-term retention may be required to prevent posttreatment changes. The bonded orthodontic retainer constructed from composite and multistrand orthodontic wire provides an esthetic and efficient system for maintained retention. The development, indications for use, and clinical techniques are described. The range of materials reported for clinical use in construction of bonded orthodontic retainers are reviewed. Recommmendations based on the literature are made. This review implicates placement of insufficient resin or use of a resin with inadequate abrasion resistance in the failure of bonded fixed retainers.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1990

Clinical acceptability of orthodontic retainers fabricated from stored alginate impressions.

The purpose of this study was to determine the clinical acceptability of orthodontic retainers fabricated from stored alginate impressions. In the laboratory, alginate impressions were made of a standard dentoform. In the clinic, maxillary alginate impressions were made of the teeth of 20 dentate adults. In each case, sets of stone models were made either immediately or after the impressions had been stored for 24 or 72 hours at high humidity. The linear dimensions of the three sets of dentoform models were compared with one another and with the standard dentoform. No differences were found. Claspless acrylic retainers were fabricated on the models from the adult subjects. The retainers were positioned in the subjects' mouths and evaluated for snap fit, stability, cervical margin fit, and self-retention. With the use of these criteria, 95% of the retainers made from impressions that were poured immediately were clinically acceptable. When impressions were stored 24 and 72 hours, the percentages of acceptable retainers were 80% and 90%, respectively. The differences in percentage of clinically acceptable retainers were not statistically significant. When impressions are stored at high humidity, a large percentage of clinically acceptable orthodontic retainers can be made from models poured as long as 72 hours after the impression is made.

Adult↗
PubMed1979

Acid etch bonded cast orthodontic retainers.

We have described a technique which involves the use of a cast orthodontic retaining appliance bonded by the acid etch technique and composite resin for semipermanent retention. The technique provides an alternative form of treatment which offers some unique advantages over previous retentive techniques.

Acid Etching, Dental↗
PubMed2003

Wear comparison of thermoplastic materials used for orthodontic retainers.

Clear thermoplastic retainers are an alternative to fixed lingual retainers and removable Hawley appliances. However, thermoplastic retainers have demonstrated poor wear resistance and durability after only a few months of use. In this study, a simulated wear device was used to compare the wear of different thermoplastic materials used for orthodontic retainers. Three thermoplastic products were evaluated: C+ (Raintree Essix, New Orleans, La),.040-in Invisacryl C (Great Lakes Orthodontics, Towanda, NY), and.040-in TR sheet material (Bay Dental Direct, Bay City, Mich). Twenty specimens were fabricated for each group. The specimens were vacuum thermoformed according to the manufacturers' recommendations and subjected to wear for 1000 cycles in a wear apparatus with steatite ceramic abraders. Depth of wear was determined by surface profilometry. The maximum peak-to-valley measurement was recorded for each specimen. Mean wear (SD) in microns was as follows: C+, 5.9 (2.4); Invisacryl C, 6.1 (2.6); and TR, 1.6 (0.9). One-way analysis of variance detected a significant difference between groups (P <.001). TR material, a hard polyethylene terephthalate glycol copolymer (PETG), demonstrated greater resistance to wear than did the other 2 materials, which were softer, polypropylene-based thermoplastics. There was no evidence to suggest a difference in mean wear between the 2 polypropylene-based materials (P >.05).

Analysis of Variance↗
PubMed2005

An investigation into the use of two polyacid-modified composite resins (compomers) and a resin-modified glass poly(alkenoate) cement used to retain orthodontic bands.

The aim of this investigation was to determine the effectiveness of a conventional glass poly(alkenoate) cement (Intact) and newer polyacid-modified composite resin cements (Transbond Plus and Ultra Band-Lok) to retain orthodontic bands. In the in vitro part of this study, stainless steel bands were cemented to 240 extracted third molar teeth in three test groups comprising Intact, Transbond Plus and Ultra Band-Lok. The force to deband (N) for all three cements was recorded using an Instron universal testing machine after the following observation periods: 20 minutes and 3, 6 and 12 months. The results indicated that all three cements increased their median force to deband after 12 months. Of the two compomers, Transbondtrade mark Plus demonstrated the highest median force to deband at all four time intervals. In the in vivo part of the study, 30 patients participated in a randomized cross-mouth clinical trial where the molar bands were cemented in place using either Intact or Transbond Plus. Ultra Band-Lok was not used in the clinical part of the study. The results showed there to be no clinically significant difference in band failure rates between the two cements. When patients were asked to score each for taste, there was a significant difference, with the glass poly(alkenoate) cement (Intact) being more acceptable than the polyacid-modified composite Transbond Plus (P < 0.001). No significant differences were observed in the in vitro median force to deband or in vivo band failure rates between the glass poly(alkenoate) cement and the polyacid-modified composite resins. The choice of cementing agent can therefore be made on patient factors, e.g. taste, or operator factors, e.g. ease of handling, cost and shelf life.

Cementation↗
PubMed2002

Case report: an unorthodox orthodontic retainer.

This case report describes the management of a patient who presented with an interdental eyelet-style retainer placed around maxillary central incisors ten years ago. At that time, the patient underwent orthodontic treatment to close a large maxillary midline diastema. The maxillary central incisors were then crowned to close the small residual midline diastema remaining after the orthodontic treatment. The wire retainer was apparently placed to prevent the diastema from reopening. The patient sought treatment ten years later when pain from necrotic pulps in these central incisors became unbearable.

Adult↗
PubMed1994

On the selection and preparation of a wire for the labial bow of an orthodontic retainer.

The Hawley retainer is often prescribed by the practitioner for part-time wear during the retentive period subsequent to a program of active, maxillary arch, orthodontic therapy. The labial bow of this retainer, while engaged, may be subjected to contact forces from sources other than the maxillary anterior teeth. The bow also experiences small deformations during placement and removal of the appliance from the oral cavity. Potential failures of the bow are: 1) inelastic bending from individual masticatory actions that change its as-prepared shape; and 2) fracture due to fatigue arising from many cycles of removing and replacing the retainer. Reported in this paper, a sequel to a previous article, are the outcomes of two experiments and a nonparametric analysis that led to the development of a set of recommendations pertaining to the selection of the wire and preparation of the labial bow. Controlled variables in this study were as-received size, alloy and temper of the wire, and heat-treatment following fabrications of bow-specimens.

Chromium Alloys↗
PubMed1977

Clinical experience with direct-bonded orthodontic retainers.

The experience obtained in clinical evaluation of forty-three direct-bonded mandibular canine-to-canine retainers after a minimum observation period of 1 year (range, 1 to 2.5 years) is summarized. Results indicate that the bonded retainer has all the advantages of a fixed soldered retainer, in addition to being invisible. Patient acceptance was excellent, and the failure rate in terms of loose retainers was low. Also, for a number of other retention problems, direct bonding with different types of lingual wire seems to open up a range of promising new possibilities.

Adolescent↗
PubMed1994

A laboratory investigation into cements used to retain orthodontic bands.

A laboratory study is presented where a technique of band retention testing is characterized. A glass polyalkenoate and a zinc phosphate cement were evaluated for band retention under simulated conditions of mechanical stress. In the absence of mechanical and other stresses there was no difference in the two cements for band retention. However, after mechanical stress was applied the glass polyalkenoate cement proved superior to the zinc polyalkenoate cement for band retention (P < 0.05). Weibull analysis is presented and described as a useful adjunct to statistical handling of band retention data.

Dental Bonding↗