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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↗
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↗
PubMed1997

Cariostatic effect of glass ionomer retained orthodontic appliances. An in vivo study.

The cariostatic effect of a fluoride releasing bonding agent was investigated and compared with a conventional composite based material in connection with bonding of orthodontic brackets in 22 homologous pairs of premolars. All subjects had malocclusions requiring orthodontic treatment with fixed appliances and extraction of at least two premolars. 6-13 weeks prior to extraction, orthodontic brackets were bonded to the labial surfaces of the extraction teeth with either a glass ionomer cement or a bis-GMA resin. Initially, the children were instructed in tooth brushing and the regular use of fluoride. After extraction, the bonded teeth were stained and evaluated in a stereo-microscope regarding the incidence and extension of initial enamel demineralisation. The zone of intact enamel adjacent to the bracket base and bonding material was measured in a stereo-microscope at four predetermined locations with the aid of an electronic ruler and scored according to four categories. The incidence of enamel demineralisation adjacent to glass ionomer bonded and composite bonded brackets was 68% and 77% respectively. In 12 pairs of premolars however, the demineralisation appeared to a lesser extent on the enamel around the brackets was generally wider when glass ionomer cement was used compared to the composite resin. These differences were statistically significant (p < 0.05) mesially and distally, but non-significant cervically and incisally. The results indicate that bonding with glass ionomer cement may have a local cariostatic effect in children requiring fixed orthodontic appliances.

Adolescent↗
PubMed1997

Comparison of occlusal contacts with use of Hawley and clear overlay retainers.

Following orthodontic treatment, an increase in the number of occlusal contacts is usually desired during retention. In this study, Hawley and clear overlay orthodontic retainers were compared relative to changes in the number of occlusal contacts. Occlusal contacts were quantified in 30 orthodontic patients at debonding, at retainer delivery, and after 3 months of retention. The paired t-test was applied to evaluate longitudinal changes in the number of and intensity of contacts. Results show that with the Hawley retainer there was a significant increase in occlusal contacts on posterior teeth and no change on anterior teeth. With the clear overlay retainer there was no significant change in either posterior or anterior contacts during retention. The retentive capacities of the two retainers differ: the Hawley retainer allows relative vertical movement (settling) of the posterior teeth while the clear overlay retainer holds teeth in their debanding position.

Acrylic Resins↗
PubMed1993

Fluoride concentration in plaque adjacent to orthodontic appliances retained with glass ionomer cement.

The fluoride concentrations in dental plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) or a resin-based composite were investigated using the split-mouth technique. 48-hour plaque was collected at 3, 8, 28 days and 6 months after the onset of orthodontic treatment. The fluoride content of the plaque samples was determined after a microdiffusion procedure with a fluoride-sensitive electrode. Significantly (p < 0.001-0.05) elevated concentrations of fluoride were found in the plaque samples collected adjacent to GIC-retained brackets compared to plaque sampled from composite-retained brackets on all sampling occasions. The results suggest that GIC-bonded brackets in orthodontic treatment may act as local long-term fluoride-releasing devices.

Acrylic Resins↗
PubMed1992

Caries associated microflora in plaque from orthodontic appliances retained with glass ionomer cement.

The caries associated microflora in dental plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) and a resin based composite was investigated using the split-mouth technique. 3, 8, and 28 days after the onset of the appliances, 48-h-old plaque was sampled. An increasing prevalence of mutans streptococci and lactobacilli in plaque from both retaining materials was found. A tendency to colonize more frequently around the composite retained brackets was noticed for both types of bacteria. The proportion of mutans streptococci in relation to the total viable count was significantly higher in plaque samples from composite retained brackets compared to GIC retained 1 month after onset of treatment. The results suggest that a less caries inducing microflora may develop when GIC is used as luting agent in orthodontic dentistry.

Adolescent↗
PubMed1994

L(+)-lactic acid production in plaque from orthodontic appliances retained with glass ionomer cement.

The lactic acid production in suspensions of plaque collected adjacent to orthodontic brackets retained with a glass ionomer cement (GIC), or a resin-based composite was investigated using a split-mouth technique. Forty-eight-hour-old plaque was collected at 3, 8, and 28 days, and 3 months after the onset of orthodontic treatment. Acid fermentation was induced by glucose and the L(+)-lactic acid concentrations were determined enzymatically after a 30-minute incubation period. Significantly (P < 0.05) lower levels of lactic acid were found in plaque from GIC-retained brackets compared with the composite controls at the 28 days and 3 months sampling occasions, respectively. The results suggest that the use of GIC as a bonding agent in orthodontics can be beneficial for patients assessed at risk of caries development.

Acrylic Resins↗
PubMed1998

The use of an orthodontic thermoplastic retainer as a provisional anterior restoration: a case report.

Children who present with extensive fractures of anterior teeth pose a difficult clinical problem. Pulpal and periodontal injuries must be carefully assessed and managed. Rapid restoration of the form and contour of the extensively fractured tooth is advisable, not only to improve esthetics but also to prevent unwanted tipping or tilting of adjacent teeth and overeruption of opposing teeth. A modified Essix retainer, simply constructed in the laboratory, can be used to provisionally restore the extensively fractured anterior tooth.

Child↗