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At least 37 records · Page 2Linked to original sources

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↗

Analyses of rampant corrosion in stainless-steel retainers of orthodontic patients.

Retainers were collected from private, university, and dental labs. After viewing these corroded and control appliances using scanning electron microscopy, corroded maxillary and mandibular retainers were selected along with a control stainless-steel retainer for in-depth chemical analysis. Using electron spectroscopy for chemical analysis, monochromated Al x-rays were rastered over areas 1.5 x 0.3 mm. After survey spectra were acquired, high-resolution multiplex scans were obtained and binding energy shifts were noted. Using Auger electron spectroscopy, a spot size of approximately 30 nm was analyzed. Photos, survey scans, and depth profiles were acquired using a 3.5kV Ar(+) ion beam that was calibrated using a SiO2 standard. Via electron spectroscopy for chemical analysis, the brown stains contained Fe and Cr decomposition products in which three carbon species were present. Proteinaceous N was found as amines or amides. No Ni was present because it had solubilized. The Cr:Fe ratio indicated severe Cr depletion in the stained regions (0.2) versus the control regions (1.3). The stained regions appeared mottled, having both dark and light areas. Via AES, the dark versus light areas of the stained regions indicated that there was an absence versus a presence of both Cr and Ni. In the dark areas corrosion penetrated 700 nm; in the light areas the depth equaled 30 nm. By comparison, the passivated layer of the control retainer was 10-nm thick. After sputtering away the affected areas, all specimens had similar spectra as the control regions. The bacterial environment created the mottled appearance and induced electrochemical potential differences so that, upon reducing the passivated layer, an otherwise corrosion-resistant alloy became susceptible to rampant corrosion. An integrated biological-biomaterial model is presented for the classic case of an orthodontic acrylic-based stainless steel retainer subject to crevice corrosion.

Acrylates↗

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↗

Orthodontic bonded retainers.

Retention is usually necessary following orthodontic treatment to overcome the elastic recoil of the periodontal supporting fibres and to allow remodelling of the alveolar bone. The degree of change is variable and largely unpredictable. Bonded lingual retainers have been shown to be an effective means of retaining aligned anterior teeth in the post-treatment position in the long term. Two basic designs of lingual bonded retainers are currently in use. Rigid mandibular canine-to-canine retainers are attached to the canines only. They are effective in maintaining intercanine width but less so in preventing individual tooth rotations. Flexible spiral wire retainers are bonded to each tooth in the segment, their flexibility allowing for physiological movement of the teeth. This design is more effective at preventing rotation of the bonded teeth. Failure of bonded retainers may occur at the wire-composite interface, at the adhesive-enamel interface or as a stress fracture of the wire. Failure of a retainer may lead to unwanted tooth movement. In many cases it will be possible to repair the appliance in the mouth. However, in some instances it will be necessary to replace the retainer. A disadvantage of fixed retainers is that they complicate oral hygiene procedures, and favour the accumulation of plaque and calculus. Despite this, the presence of a bonded retainer appears to cause no increase in incidence of caries or periodontal disease. Use of interdental cleaning aids is required to ensure adequate oral hygiene.

Dental Bonding↗

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↗

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↗

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↗

Enhancing wire-composite bond strength of bonded retainers with wire surface treatment.

Bonded orthodontic retainers with wires embedded in composite resin are commonly used for orthodontic retention. The purpose of this study was to test, in vitro, various wire surface treatments to determine the optimal method of enhancing the wire-composite bond strength. Coaxial wires and stainless steel wires with different surface treatments were bonded to bovine enamel and then pulled along their long axes with an Instron universal testing machine. Wire surface treatments included placing a right-angle bend in the wire, microetching the wire, and treating the wire with adhesion promoters; combinations of treatments were also examined. The results demonstrated a 24-fold increase in the wire-composite bond strength of wire that was microetched (sandblasted), compared with that of untreated straight wire. The difference between the amount of force required to break the bond produced by microetching alone (246.1 +/- 46.0 MPa) and that required for the bonds produced by the retentive bend (87.8 +/- 16.3 MPa), the adhesion promoters (silane, 11.0 +/- 3.1 MPa; Metal Primer, 28.5 +/- 15.8 MPa), or for any combination of surface treatments, was statistically significant. Microetching a stainless steel wire produced a higher wire-composite bond strength than that obtained from a coaxial wire (113.5 +/- 27.5 MPa). The results of this study indicate that microetching or sandblasting a stainless steel wire significantly increases the strength of the wire-composite bond.

Animals↗

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↗

Intra-oral temperature variation over 24 hours.

This study aimed to investigate temperature variation at archwire sites adjacent to the maxillary right central incisor and first premolar, its correlation with ambient temperature, and the influence of inter-racial variation. Twenty young adult male subjects were randomly selected (13 Asian, seven Caucasian). Thermocouples were attached to the labial archwire component of custom-made orthodontic retainers at the two intra-oral sites. A third thermocouple measured ambient temperature. A data-logger recorded temperatures at 5-second intervals over a 24-hour period. Temperatures ranged from 5.6 to 58.5 degrees C at the incisor and from 7.9 to 54 degrees C at the premolar, with medians of 34.9 degrees C and 35.6 degrees C, respectively. Ambient temperature correlated poorly with the intra-oral temperatures. The Asian and Caucasian groups had significantly different temperature distributions. On average during the 24-hour period, temperatures at the incisor site were in the range of 33-37 degrees C for 79 per cent of the time, below it for 20 per cent, and above it for only 1 per cent of the time. Corresponding figures for the premolar site were 92, 6, and 2 per cent. At both archwire sites the most frequent temperatures were in the range of 35-36 degrees C. The data presented demonstrate that the temperature at sites on an archwire in situ varies considerably over a 24-hour period and that racial differences may exist. This information should be considered during the manufacture and use of temperature-sensitive orthodontic materials, in particular nickel-titanium archwires and springs.

Adult↗

Orthodontic treatment for posterior crossbites.

BACKGROUND: 'Posterior crossbite' occurs when the top back teeth bite inside the bottom back teeth. When it affects one side of the mouth the lower jaw may have to move to one side to allow the back teeth to meet together. This movement may have long term effects on the growth of the teeth and jaws. It is unclear what causes posterior crossbites and they may develop or improve at any time from when the baby teeth come into the mouth to when the adult teeth come through. Several treatments have been recommended to correct them. Some treatments widen the upper teeth whilst others are directed at treating the cause of the posterior crossbite e.g. breathing problems or sucking habits. Most treatments have been used at each stage of dental development. OBJECTIVES: The aim of this review was to identify and evaluate orthodontic treatments used to expand the maxillary dentition and / or correct posterior crossbites. SEARCH STRATEGY: All randomised and controlled clinical trials identified from the Cochrane Controlled Trials Register according to the Oral Health Group Search Strategy and stored in the Cochrane Collaboration Oral Health Group Database of Clinical Trials, a MEDLINE search using the Mesh term and free text words, hand searching the British, European and American journals of orthodontics and Angle Orthodontist, and the bibliographies of papers and review articles which reported the outcome of orthodontic treatment to expand the maxillary dentition and/or correct a posterior crossbite that were published as abstracts or papers between 1970 and 1997 in English. SELECTION CRITERIA: All randomised and controlled clinical trials published as full papers or abstracts which reported quantitative data on the outcomes crossbite correction, molar and/or canine expansion, signs and symptoms of temporomandibular joint dysfunction or respiratory disease. DATA COLLECTION AND ANALYSIS: Data were extracted without blinding to the authors, treatments used or results obtained. The first named authors of randomised and controlled clinical trials were written to in an attempt to establish the method of randomisation / allocation and identify unpublished studies. Odds ratio, 95% confidence intervals, relative risk, relative risk reduction, absolute risk reduction, and the number need to treat were calculated for event data. The weighted mean difference and 95% confidence intervals were calculated for continuous data. MAIN RESULTS: Using the search strategy 7 randomised and 5 controlled clinical trials were identified but following correspondence with the authors, 3 of the randomised and 1 of the controlled clinical trials were reclassified giving 5 randomised and 7 controlled clinical trials for inclusion in the review. Trials comparing occlusal grinding in the primary dentition with/without an upper removable expansion appliance in the mixed dentition versus no treatment, banded versus bonded rapid maxillary expansion, banded versus bonded slow maxillary expansion, transpalatal arch with/without buccal root torque and an upper removable expansion appliance versus quad-helix were identified. Occlusal grinding in the primary dentition with/without the addition of an upper removable expansion plate, in the mixed dentition for those children who did not respond to grinding, was shown to be effective in preventing a posterior crossbite in the primary dentition from being perpetuated to the mixed and permanent dentitions. No evidence of a difference in treatment effect (molar and canine expansion) between the test and control intervention was found in the trials which compared banded versus bonded rapid maxillary expansion, banded versus bonded slow maxillary expansion, transpalatal arch with/without buccal root torque, or upper removable expansion appliance versus quad-helix. (ABSTRACT TRUNCATED)

Adult↗

Decontamination of tried-in orthodontic molar bands.

Molar bands are commonly used to retain orthodontic attachments on posterior teeth and due to the variation in the size of such teeth, it is usually necessary to 'try in' several bands before the correct one is selected. A possible concern with re-using such bands is the lack of cross-infection control, even following autoclaving, due to the presence of one or more small bore lumen (the archwire and headgear tubes). The aim of this experiment was, therefore, to determine whether such bands could be successfully decontaminated so that they could be re-used without a cross-infection risk. Two hundred orthodontic molar bands that had previously been tried in patients' mouths, but not cemented into place, were tested. Each band was decontaminated using an enzymatic cleaner/disinfectant and then sterilized using either a downward displacement (n = 100) or a vacuum cycle autoclave (n = 100). Following autoclaving each band was inoculated into brain heart infusion culture broth and incubated at 37 degrees C for 5 days. None of the decontaminated bands exhibited growth after 5 days. It would appear that, using this methodology, there is little risk of a cross-infection hazard occurring with the re-use of previously tried-in and decontaminated molar bands.

Cross Infection↗

Four applications of reinforced polyethylene fiber material in orthodontic practice.

Four different orthodontic applications of a polyethylene fiber material are shown and discussed in case reports. Ribbond (Ribbond Inc, Seattle, Wash), a bondable, reinforced polyethylene fiber material, was successfully used in a fixed orthodontic retainer, a space maintainer, a temporary postorthodontic fixation device to attach a pontic to abutment teeth during periodontal therapy, and a posttraumatic stabilization splint. This clinical practice was based on earlier studies showing that the polyethylene fiber material adapted easily to dental contours and could be manipulated during the bonding process. It also has acceptable strength because of good integration of fibers with composite resin; this leads to good clinical longevity. Because thinner composite resins can be used, the volume of the splint can be minimized. There is no need for significant tooth structure removal, so the technique is reversible and conservative. It also satisfies patients' esthetic expectations. These cases show that Ribbond is a promising splint material for use in orthodontic practice.

Adolescent↗

Self-injurious behavior as a challenge for the dental practice: a case report.

Patients who present self-injurious behavior (SIB) can be considered a treatment challenge in the dental office or hospital setting. Oral structures can play various roles in the process of self injury. In this paper, the authors report a case of SIB in the form of cheek-biting on an adolescent with a history of hydrocephalus and developmental delay, which was successfully treated with a modified standard maxillary orthodontic retainer. Early detection and intervention in SIB cases in patients with developmental disabilities influence the successful outcome of the therapeutic interventions, enhancing the patient's quality of life.

Adolescent↗