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PubMed2005

A comparison of the shear bond strength of a resin cement and two orthodontic resin adhesive systems.

The object of this study was to compare the shear bond strength and the quantity of adhesive remaining on the tooth after the debonding of brackets bonded with two light-cured orthodontic resin adhesive systems (Transbond XT and Light-Bond) and a dual-cured resin cement (RelyX Unicem). Seventy-five premolars were divided into three groups. In each group, brackets were bonded with one of the adhesives according to the manufacturer's instructions. Shear bond strength was measured using a universal test machine at a crosshead speed of one mm/min, and adhesive remnant was quantified using image analysis equipment. Our results showed that the resin cement produced significantly lower bond strength than the two orthodontic resin adhesive systems. It was also observed that the bond strength produced by Light-Bond was significantly greater than that of Transbond XT. RelyX left significantly less remnant adhesive than Transbond XT and Light-Bond. Between the two orthodontic systems, Light-Bond left significantly less adhesive on the tooth than Transbond XT.

Bicuspid↗
PubMed2005

Measurement of white lesions surrounding orthodontic brackets: captured slides vs digital camera images.

Digital images provide an efficient means of processing and storing clinical images and are increasingly being used in orthodontic practice. However, for research purposes it must be shown that measurements from digital images are as reliable as those from captured slides, particularly in the area of postorthodontic demineralization. The aim of this in vitro study was to compare the assessment of demineralized white lesions surrounding orthodontic brackets using images produced from captured slides with those from a digital camera. Thirty teeth with orthodontic brackets and a systematic arrangement of artificially induced demineralization were used. Standardized images of the teeth were taken in 35-mm slide format and using a digital camera. The slides were scanned and saved as digital images. All the images were numbered, recoded in a random order, and assessed by a second investigator. The image was examined for the presence or absence of demineralization. This was compared with the actual demineralization pattern, and the positive and negative predictive values were calculated. Twenty images from each group were randomly chosen and duplicated for an assessment of measurement error. The positive and negative predictive values were better from the digital images (0.92 and 0.81) than from the captured slides (0.88 and 0.74). The percentage agreements for the repeat assessments of the same slide were similar (96% for the captured slides and 93% for the digital images). Measurements of enamel demineralization using images from a digital camera are as accurate and reproducible as images captured from a photographic slide.

Dental Enamel↗
PubMed2005

Acceptability and perceived effectiveness of web-based self-instruction in clinical orthodontics.

For a predoctoral course in advanced clinical orthodontics, we evaluated the acceptability to students (how well did you like it?) and the perceived effectiveness (how well did it help you learn?) of Web-based self-instruction plus small-group seminars. On a 10-point Likert scale, median scores for acceptability and effectiveness of the self-instructional modules and seminars were nine. More than half the students rated the modules as excellent, and two-thirds rated the seminars as excellent. No students rated either the modules or the seminars as poor. With the use of structured seminar outlines, there were no significant differences in seminar scores among the seminar leaders. Compared with their predecessors who had a traditional lecture course, students who had the new self-instructional course were less likely to report either the positive or negative extremes in confidence about their ability to recognize treatment alternatives for orthodontic problems. The results indicate that Web-based self-instruction plus small-group seminars coordinated by a course leader is at least as effective as traditional lectures. This approach offers a possible way to share faculty among orthodontic departments for both pre- and postdoctoral education, as a way to help overcome faculty shortages.

Computer-Assisted Instruction↗
PubMed2005

Orthodontic anchorage implants inserted in the median palatal suture and normal transverse maxillary growth in growing dogs: a biometric and radiographic study.

Small osseointegrated implants inserted in the palate provide a reliable anchorage control during orthodontic treatment. When these implants are inserted in the median palatal suture in growing individuals, the possible effects on normal transverse maxillary growth are still unknown. Therefore, the aim of this study was to evaluate the influence of orthodontic anchorage implants on transverse maxillary growth when inserted in the median palatal suture of growing dogs. Five growing dogs were used, one of them randomly selected as a control dog. The test dogs each received two implants in the median palatal suture. Impressions and occlusal radiographs of the upper jaws were taken at baseline (TO), after 84 days (T1), and at the end of the study after 168 days (T2). Measurements to compare increases in maxillary width between test dogs and control dog were performed on study casts and occlusal radiographs at TO, T1, and T2. Restricted transverse growth was observed in the test dogs in the canine region. Transverse growth in the region of second and fourth premolars was similar for the test dogs and the control dog. These results may be of some clinical relevance when orthodontic anchorage implants are to be inserted in growing individuals. An alternative insertion site, for example the parasagittal region, should be considered in these cases, to avoid possible negative effects on normal transverse maxillary development.

Animals↗
PubMed2005

Shear bond strength of metallic orthodontic brackets bonded to enamel prepared with Self-Etching Primer.

The aim of this study was to determine the shear bond strength of different composites and to determine the adhesive remnant index (ARI) of metallic brackets bonded to enamel prepared with Transbond Plus Self-Etching Primer (TPSEP). Forty human premolars were divided into four equal groups. In group 1 (control), the Transbond XT was conventionally used. In groups 2-4, the TPSEP was used before bonding with Transbond XT, Z-100, and Concise Orthodontic, respectively. After the bonding, the samples were stored in distilled water at 37 degrees C for 24 hours. The brackets were debonded using a universal testing machine at a crosshead speed of 0.5 mm/ min. The shear bond strength (MPa) for group 1 (control), group 2 (TPSEP + Transbond XT), group 3 (TPSEP + Z-100), and group 4 (TPSEP + Concise Orthodontic) were of 6.43, 4.61, 4.74, and 0.02, respectively. Group 1 was statistically superior to other groups (P < .05), but there was no statistically significant difference between groups 2 and 3 (P > .05), although both were statistically superior to group 4 (P < .05). According to the ARI evaluation, most of the failures involved the bracket/composite interface (groups 1 and 2) as well as the enamel/composite interface (groups 3 and 4). The Transbond XT conventionally bonded showed better adhesion results than Transbond XT, Z-100, and Concise Orthodontic after using Transbond Plus Self-Etching Primer.

Acid Etching, Dental↗
PubMed2005

Two- and three-dimensional orthodontic imaging using limited cone beam-computed tomography.

Considerable progress has been made in diagnostic, medical imaging devices such as computed tomography (CT). However, these devices are not used routinely in dentistry and orthodontics because of high cost, large space requirements and the high amount of radiation involved. A device using computed tomography technology has been developed for dental use called a limited cone beam dental compact-CT (3DX). The aim of this article is to demonstrate the usefulness of 3DX imaging for orthodontic diagnosis and treatment planning. We present three cases: (1) one case shows delayed eruption of the upper left second premolar, (2) the second case shows severe impaction of a maxillary second bicuspid; and (3) the third case shows temporomandibular joint disorder (TMD). In the tooth impaction cases, the CT images provided more precise information than conventional radiographic images such as improved observation of the long axis of the tooth, root condition, and overlap with bone. In the TMD case, clear and detailed temporomandibular joint images were observed and pre- and posttreatment condylar positions were easily compared. We conclude that 3DX images provide useful information for orthodontic diagnosis and treatment planning.

Adolescent↗
PubMed2006

Early shear bond strength of a one-step self-adhesive on orthodontic brackets.

OBJECTIVE: The purpose of this study was to determine whether a self-adhesive universal cement, RelyX Unicem (3M ESPE, Seefeld, Germany), can be used successfully to bond orthodontic brackets to enamel. MATERIALS AND METHODS: Forty human molars were cleaned, mounted, and randomly divided into two groups: 20 orthodontic brackets were bonded to teeth using RelyX Unicem, and 20 brackets were bonded using the Transbond XT (3M Unitex, Monrovia, Calif) adhesive system. The teeth were debonded within 30 minutes after initial bonding using a universal testing machine. After debonding, the enamel surface was examined under 10x magnification to determine the amount of residual adhesive remaining on the tooth. Student's t-test was used to compare the shear bond strength (SBS) of the two groups, and the chi-square test was used to compare the Adhesive Remnant Index (ARI) scores for the two adhesive systems. RESULTS: The mean SBS of the brackets bonded using the RelyX Unicem was 3.7 +/- 2.1 MPa and was significantly lower (t = 2.07, P = .048) than the SBS of the brackets bonded with the Transbond system (x = 5.97 +/- 4.2 MPa). The comparisons of the ARI scores between the two groups (chi(2) = 17.4) indicated that bracket failure mode was significantly different (P = .002) with more adhesive remaining on the teeth bonded with Transbond XT. CONCLUSIONS: The SBS of the self-adhesive universal cement needs to be increased for it to be successfully used for bonding orthodontic brackets.

Adhesiveness↗
PubMed2002

Diagnostic features and pedodontic-orthodontic management in dentinogenesis imperfecta type II: a case report.

Dentinogenesis imperfecta type II, also known as hereditary opalescent dentin, is an isolated inherited condition transmitted as an autosomal dominant trait affecting the primary and permanent dentition. The combined pedodontic-orthodontic management of a 4-year-old child is described. Following orthodontic analysis to encourage a favourable growth outcome, treatment comprised restoration of the primary teeth with stainless steel crowns and composite crowns. Differential diagnosis and alternative therapies, including orthodontic considerations, are discussed.

Cephalometry↗
PubMed2001

Effect of a self-etch primer/adhesive on the shear bond strength of orthodontic brackets.

Conventional adhesive systems use 3 different agents (an enamel conditioner, a primer solution, and an adhesive resin) during the bonding of orthodontic brackets to enamel. A unique characteristic of some new bonding systems in operative dentistry is that they combine the conditioning and priming agents into a single product. Combining conditioning and priming saves time and should be more cost-effective to the clinician and, indirectly, to the patient. The purpose of this study was to determine the effects of the use of a self-etch primer on the shear bond strength of orthodontic brackets and on the bracket/adhesive failure mode. Brackets were bonded to extracted human teeth according to 1 of 2 protocols. In the control group, teeth were etched with 37% phosphoric acid. After the sealant was applied, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and light cured for 20 seconds. In the experimental group, a self-etch acidic primer (ESPE Dental AG, Seefeld, Germany) was placed on the enamel for 15 seconds and gently evaporated with air, as suggested by the manufacturer. The brackets were then bonded with Transbond XT as in the first group. The present in vitro findings indicate that the use of a self-etch primer to bond orthodontic brackets to the enamel surface resulted in a significantly (P = .004) lower, but clinically acceptable, shear bond force (mean, 7.1 +/- 4.4 MPa) as compared with the control group (mean, 10.4 +/- 2.8 MPa). The comparison of the adhesive remnant index scores indicated that there was significantly (P = .006) more residual adhesive remaining on the teeth that were treated with the new self-etch primer than on those teeth that were bonded with the use of the conventional adhesive system.

Acid Etching, Dental↗
PubMed2001

Orthodontic spring guidance of bilateral mandibular distraction in rabbits.

Although distraction osteogenesis can lengthen congenitally small mandibles, the distraction procedure can be difficult to control. To study the efficacy and safety of orthodontic spring guidance on bilateral mandibular distraction, an 8-mm anterior open bite was experimentally produced and corrected during bilateral mandibular distraction in rabbits. Orthodontic springs were attached to the anterior maxilla and mandible to redirect an ongoing distraction procedure. Sixteen rabbits underwent mandibular distraction: 6 rabbits received heavy springs (8 oz), 6 rabbits received light force springs (2 oz), and 4 rabbits served as control animals with anterior open bites without spring guidance. Nickel-titanium springs were applied during the last week of osseous distraction and the first week of consolidation. Distractors were left in place throughout a 2-month consolidation period. None of the animals developed fibrous union as a result of spring guidance. The 8-mm open bite did not close in the control group or in the light spring group after 2 weeks of spring wear or during the consolidation period. Heavy springs completely closed the experimental open bites within 2 weeks (P <.01, analysis of variance). Bite corrections did not change during the consolidation period. This study indicated that the addition of an orthodontic spring to a mandibular distraction procedure did not impair bone healing. With the distraction device in place, heavy spring forces redirected an ongoing mandibular distraction procedure and corrected an open bite, distraction side effect. Direct measurements, radiographic measurements, and tissue histologic factors described changes in segment position and shape of the distraction site.

Analysis of Variance↗
PubMed2001

The effect of preemptive and/or postoperative ibuprofen therapy for orthodontic pain.

The control of pain during orthodontic treatment is of vital interest to both clinicians and patients. Surprisingly, there has been limited research into the control of orthodontic pain, and there is no standard of care for controlling this discomfort. The purpose of this study was to compare the effectiveness of preemptive ibuprofen therapy, postoperative ibuprofen therapy, and a combination of the 2 therapies. Forty-one orthodontic patients aged 9 years 3 months to 16 years 11 months who were to undergo separator placement were enrolled in this prospective study. Patients were randomly assigned to 1 of 3 experimental conditions: (1) 400 mg ibuprofen taken orally 1 hour before separator placement and 400 mg ibuprofen taken orally 6 hours after the initial dose, (2) 400 mg ibuprofen taken orally 1 hour before separator placement and a lactose capsule taken orally 6 hours after the initial dose, or (3) a lactose capsule taken orally 1 hour before separator placement and 400 mg ibuprofen taken 6 hours after the initial placebo. The results revealed that preemptive ibuprofen therapy significantly decreased pain that was experienced 2 hours after separator placement and at bedtime. Beginning on day 2, there was a trend for patients who had taken both preemptive and postoperative ibuprofen doses to have lower pain scores compared with the other 2 groups. In conclusion, these data indicate that ibuprofen taken 60 minutes before separator placement alleviates pain at 2 hours and at bedtime after treatment. Further study with the use of additional postoperative doses is warranted.

Administration, Oral↗
PubMed2001

A review of orthodontic cements and adhesives.

Dental cements and resins are used intraorally to secure fixed orthodontic devices. Although cements are still used, the popularity of resin and resin-cement hybrid materials is increasing because of their improved physical properties and low solubility in oral fluids. Some cements bond chemically to enamel, but bond strengths are low because cements are brittle and fracture cohesively. Resin adhesives penetrate micropores in etched enamel and mechanical retentions in orthodontic devices, resulting in higher bond strengths because resins are more fracture resistant than cements. Resins, however, do not bond well in the presence of moisture, and their attachment to surfaces is primarily mechanical. Hybridized materials combine the advantages of cements and resins but also have certain disadvantages. Optimal material selection and application require an understanding of the chemical differences and physical limitations of today's orthodontic cements, resins, and hybrid materials.

Acid Etching, Dental↗
PubMed2001

Metal release from simulated fixed orthodontic appliances.

Most orthodontic appliances and archwires are stainless steel or nickel-titanium (NiTi) alloys that can release metal ions, with saliva as the medium. To measure metal released from the fixed orthodontic appliances currently in use, we fabricated simulated fixed orthodontic appliances that corresponded to half of the maxillary arch and soaked them in 50 mL of artificial saliva (pH 6.75 +/- 0.15, 37 degrees C) for 3 months. We used brackets, tubes, and bands made by Tomy (Tokyo, Japan). Four groups were established according to the appliance manufacturer and the type of metal in the .016 x .022-in archwires. Groups A and B were stainless steel archwires from Ormco (Glendora, Calif) and Dentaurum (Ispringen, Germany), respectively, and groups C and D were both NiTi archwires with Ormco's copper NiTi and Tomy's Bioforce sentalloy, respectively. Stainless steel archwires were heat treated in an electric furnace at 500 degrees C for 1 minute and quenched in water. We measured the amount of metal released from each group by immersion time. Our conclusions were as follows: (1) there was no increase in the amount of chromium released after 4 weeks in group A, 2 weeks in group B, 3 weeks in group C, and 8 weeks in group D; (2) there was no increase in the amount of nickel released after 2 weeks in group A, 3 days in group B, 7 days in group C, and 3 weeks in group D; and (3) there was no increase in the amount of iron released after 2 weeks in group A, 3 days in group B, and 1 day in groups C and D. In our 3-month-long investigation, we saw a decrease in metal released as immersion time increased.

Chromium↗
PubMed2001

Orthodontic treatment in long-term survivors after pediatric bone marrow transplantation.

Children treated for childhood cancers with both radiation and chemotherapy often exhibit disturbances in dental development. A retrospective analysis of treatment outcome in 10 orthodontically treated children was performed. A questionnaire was sent to each child's orthodontist, and 5 orthodontists reported that the patient's medical condition influenced their choice of treatment plan. Three orthodontists, all treating patients with severely disturbed root development, reported using lighter forces than they used with the average patient. With regard to complications related to orthodontic treatment, 1 of the 10 patients showed evidence of root resorption. In 4 of the 10 patients, the treatment result was judged to be unsatisfactory. This study showed that, although ideal treatment results were not always achieved, orthodontic treatment did not produce any harmful side effects in children who are long-term survivors of childhood cancer.

Adolescent↗
PubMed2001

Fluoride release from new light-cured orthodontic bonding agents.

The purpose of this study was to compare the rates of fluoride release with time from 1 nonfluoridated and 3 fluoride-containing orthodontic bonding materials in distilled water and artificial saliva. Materials tested were Assure (Reliance Orthodontic Products, Itasca, Ill), Fuji Ortho LC (GC, Tokyo, Japan), Python (TP Orthodontics, LaPorte, Ind), and Transbond XT (3M Dental Products, Monrovia, Calif). Ten specimens of each material type were stored in distilled water, and 10 of each type were stored in artificial saliva at 37 degrees C. Fluoride release was measured with an ion-specific electrode. Readings were taken periodically for a total time period of 6 months. At day 1, Assure released the most fluoride into distilled water (66.2 microg/cm(2)) and into artificial saliva (65.8 microg/cm(2)), followed by Fuji Ortho LC (25.9 microg/cm(2); 18.8 microg/cm(2)), Python (6.3 microg/cm(2); 4.2 microg/cm(2)), and Transbond (0.1 microg/cm(2); 0.1 microg/cm(2)). The fluoride release rates were highest during the first days of testing, declining to lower but more stable levels. At the end of 6 months, Fuji Ortho LC released the most fluoride (3.8 microg/cm(2); 3.5 microg/cm(2)) followed by Assure (3.1 microg/cm(2); 2.8 microg/cm(2)), Python (2.6 microg/cm(2); 1.7 microg/cm(2)), and Transbond (0.1 microg/cm(2); 0.1 microg/cm(2)). The type of storage medium did not dramatically affect fluoride release. The second part of the study, undertaken after a year of sample storage, tested the 20 samples of Assure for a further 2-week period, after exposure to running and still distilled water. Although fluoride release rates declined with time, they were still higher than the 1.5 microg/cm(2) level that is referenced as inhibiting decalcification of enamel in a clinical environment. Release rates were similar in running and still water at all time points. Throughout the 6-month period, all 3 fluoride-containing materials had rates of fluoride release that could theoretically inhibit decalcification of enamel.

Acrylic Resins↗
PubMed2001

Bond strength of fiber-reinforced composite bars for orthodontic attachment.

Long fiber-reinforced composites (FRC) have been shown to have enhanced mechanical properties that allow their use in orthodontic appliances as bars that join teeth to form either anchorage or active units. This study was designed to determine if the bonding of an orthodontic attachment has sufficient strength to withstand loading during clinical use. The experimental model consisted of a hydroxyapatite stone that simulated enamel, FRC bars, and a bonded metal hook. Three specimen types were compared: (1) a metal hook-pad (the control), (2) a woven FRC with a hook-pad, and (3) a unidirectional FRC with a hook-pad. Loads were applied both parallel and at 90 degrees to the tooth surface. Under no condition was the FRC pad combination weaker than the control pad. Under some loading conditions, the loads before failure were as much as 3 times greater than those for the control. The lowest strength was found with loads at 90 degrees to the tooth surface for all 3 types. Failure normally occurred in the FRC and rarely at the bracket or tooth interface. The excellent bonding of the orthodontic attachment to the FRC and the high strengths of the FRC attachment combination demonstrate the ability to form connecting bars between teeth for either anchorage or active segmental movements. These bars offer advantages in simplicity in treatment by reducing the need for some bands, attachments, or wires.

Composite Resins↗
PubMed2002

Orthodontic correction of transverse arch asymmetries.

The purpose of this study was to determine whether asymmetries in the transverse dimension are corrected after orthodontic treatment and to determine differences between age-group responses in the correction of transverse asymmetries. Sixty orthodontically treated subjects with transverse asymmetries in arch width were grouped by age, treatment modality, and arch location. Casts were analyzed to assess the correction of arch asymmetry. Lateral cephalometric analysis was performed to assess vertical change differences between age groups, and to detect correlations between vertical and arch-width changes. After orthodontic treatment, it was found that the arch width between the 2 halves of the arch still showed significant differences (P < .05); it was also found that arch-width changes between pretreatment and posttreatment showed significant differences (P < .05) for nonextraction treatment and for the anterior region in extraction treatment. Analysis of lateral cephalograms showed significant differences (P < .05) in vertical-dimension changes between growing and nongrowing subjects. The Pearson product moment correlation test showed no significant correlation at the P < .05 level between vertical and arch-width changes. We concluded that, for this sample, asymmetry in transverse dimension was not corrected, and there was no difference between growing and nongrowing individual responses in transverse asymmetry correction.

Adolescent↗
PubMed2002

Orthodontic graduate education survey, 1983-2000.

Throughout academic year 1999/2000, the fourth in a series of national surveys sponsored by the American Association of Orthodontists Council on Education was conducted to determine the status of graduate education, to assemble information on the didactic and clinical material being taught, and to provide a basis for comparison with past and future studies. The results of the previous studies were published in 1984, 1989, and 1995. The specific purpose of the 2000 study was to identify trends and evaluate new developments in orthodontic education over the past 17 years. A 346-item survey questionnaire, covering 8 major areas of orthodontic graduate education, was sent to graduate program directors in the United States and Canada. The major areas analyzed were program organization, graduate students, faculty, facilities, clinical details, treatment techniques, research, and curriculum. Findings showed that curricular time devoted to clinical activities is increasing, but curricular time devoted to research is declining. The rate of student publications is down precipitously. The numbers of full-time and half-time faculty members are declining, and departments increasingly rely on part-time faculty to meet teaching needs. Overall experience levels of the faculty are declining. Fewer faculty members are American Board of Orthodontics diplomates. Faculty salaries, when adjusted for inflation, are down from 1994. Tuitions have increased dramatically over the last 5 years. Approximately 50% of all programs are now 3 years long. Clinic fees are now roughly two thirds those of local private-practice fees. Students are treating more mixed dentition and craniofacial cases and fewer nonsurgical adult cases. Fewer departments are relying on centralized radiographic facilities in their parent dental schools, preferring in-department radiography. Approximately 50% of the first-year students are female.

Adult↗