World journal of orthodontics最新文献

Aim: To study in vitro the bond strength of three adhesive systems on lingual brackets.

Methods: Forty-five extracted human mandibular premolars were randomly divided into three groups of 15 specimens each. All brackets (Stealth lingual brackets) were bonded with Transbond XT Light Cure Adhesive. In group 1, the conventional primer was used; in group 2, Transbond Moisture Insensitive Primer was employed; and in group 3, an antimicrobial self-etching primer (Clearfil Protect Bond) was used.

Results: The highest mean bond strength values were observed when Clearfil Protect Bond (13.54 ± 0.58 MPa) was used and the lowest after applying the conventional Transbond XT primer (6.41 ± 0.43 MPa). The mean bond strength in group 2 was 8.20 ± 0.50 MPa, which was significantly higher than that of group 1.

Conclusion: Besides its antimicrobial effect, Clearfil Protect Bond results in high bond strength values. Therefore, this product might be preferable when bonding lingual brackets.

Aim: To assess whether the forces created by the magnetic resonance imaging (MRI) field cause a deflection of orthodontic stainless steel archwires or a change of their mechanical properties.

Methods: Sixty stainless steel 0.016-inch archwires were divided into three groups of 20 wires each. The control group was as received from the manufacturer, the MRI 1 group had wires attached to brackets on artificial teeth subjected to MRI (1.5 Tesla), and the MRI 2 group had activated T-loops subjected to MRI (1.5 Tesla). The mechanical properties were compared between the control group and MRI 1 group, whereas in the MRI 2 group, the change in the amount of activation was measured. The data were evaluated by repeated measurement analysis with independent and paired t tests.

Results: Tensile strength did not differ significantly between the control group and the MRI 1 group (P=.64). In the MRI 2 group, the mean distance between the vertical loop legs before and after MRI did not differ significantly (P=.53).

Conclusion: The magnetic field did not significantly affect the mechanical properties of the tested stainless steel wires, nor did it change the loop activation.

Aim: To determine the correlation among chronologic age, skeletal maturity, and dental age in reference to both sexes.

Methods: In 380 subjects (147 males and 233 females) between 7 and 17 years of age, skeletal maturity was assessed using the cervical vertebral maturation stages described by Baccetti et al. Dental age was determined using the Demirjian method. The correlation between skeletal maturity and chronologic age on one side and between skeletal maturity and dental age on the other was assessed with Spearman rank correlation coefficients. Pearson correlation coefficients were used to assess the correlation between chronologic and dental age.

Results: For both sexes, significant correlations among chronologic age, skeletal maturity, and dental age were found. The mandibular first premolar had the highest correlation with skeletal maturation in both sexes.

Conclusion: As skeletal maturity and dental age are significantly correlated, tooth development may be used to assess a patient's skeletal maturity at an early age.

Aim: Conventionally, noncompliance distal movement of molars relies exclusively on intraoral anchorage. The distal screw, a distal jet appliance supplemented by two paramedian mini-implants, is an innovative alternative. The aim of this study was to evaluate the suitability of this device to move molars bodily and distally.

Methods: The effects of the distal screw were evaluated in a sample of 18 consecutively treated preadolescent and adolescent individuals (nine females and nine males; mean age at the start of treatment, 11.2 years). Two conical mini-implants (length 11.0 mm, diameter 1.5 to 2.2 mm) were placed in the anterior paramedian area of the palate of each patient. The coil springs of the device were activated to deliver a force of 240 cN per side. The dental and skeletal effects were investigated on pre- and posttreatment cephalometric radiographs.

Results: The distal screw produced a Class I occlusion of the first molars by moving them distally 4.7 mm, which is more than conventional appliances can accomplish. Although this took longer than conventional devices (9.1 months), it had the advantage of a roughly 2.1-mm premolar distal movement (ie, no anchorage loss as with traditional techniques).

Conclusions: The distal screw anchored by two palatal mini-implants allows not only translatory molar distal movement, but also distal movement of the maxillary first premolars, thereby avoiding characteristic anchorage loss.

Aim: To evaluate the stability of self-drilling mini-implants used for immediate en masse retraction of all anterior teeth.

Methods: Six patients with 12 self-drilling mini-implants (diameter 1.6 mm, length 6.0 mm), which were placed on each side between the maxillary first molar and second premolar, were evaluated. The mini-implants were loaded immediately after placement with a force of 200 cN. Lateral cephalograms were taken upon loading (T1) and after 6 months of retraction (T2). All T1 and T2 radiographs were analyzed by localizing the anterior border of the mini-implant heads. Their vertical displacement was measured in millimeters to the Frankfort plane; the horizontal displacement was measured to a line perpendicular to the Frankfort plane registered at sella.

Results: Analysis of variance revealed a significant difference for the horizontal (P<.05) but not for the vertical pre- and posttreatment position.

Conclusion: Mini-implants provide good anchorage for the retraction of teeth. However, the self-drilling mini-implants used in this study did not remain absolutely stationary like osseointegrated implants. With loading, they moved in the direction of the applied force, but their displacement had no clinical impact.

Aim: To examine the efficiency and effectiveness of the SureSmile process using the standards of the American Board of Orthodontists Objective Grading System (ABO OGS).

Methods: Three diplomates of the American Board of Orthodontics provided study casts of 62 patients whose orthodontic treatment was consecutively completed. Patients treated using the SureSmile process and a conventional approach were anonymized and randomized prior to independent scoring by two ABO OGS-calibrated examiners.

Results: Intra- and interexaminer reliability was consistent in all components with no differences between examiners (r=0.96, P<.001). The ABO OGS score for the SureSmile patients (mean 26.3) was 4.4 points lower (P<.001) than for those treated conventionally (mean 30.7). Furthermore, treatment with the SureSmile process was shorter (14.7 months vs 20.0 months).

Conclusion: The SureSmile process results in a lower mean ABO OGS score and a reduced treatment time than conventional approaches. The approach has great potential to both decrease treatment time and improve quality.

This article describes the usefulness of Cariogram software in three orthodontic patients with high-, medium-, and low-risk caries profiles. Caries-related indicators and information needed for the Cariogram model were registered. The prebonding decayed and filled surfaces (DFS) indices for patient 1 (15-year-old girl) and patient 2 (18-year-old woman) were >5, while in patient 3 (15-year-old boy), the DFS index was <2. The data were entered into the interactive Cariogram software, which shows the various caries-related indicators. Patients 1, 2, and 3 had 6%, 58%, and 87%, respectively, actual chance of avoiding new caries. Patient 1 had high lactobacilli and medium mutans streptococci scores and a high caries risk. Patient 2 had a high DFS index and low buffer capacity, resulting in a medium caries risk. Patient 3 had low mutans streptococci and high lactobacilli scores and a low DFS index, resulting in a low caries risk. The Cariogram is available free online and is a useful educational model to illustrate a patient's caries risk.

In general, the success of Class II treatment depends as much on the skill of the orthodontist as it does on a favorable facial-growth pattern. Lack of sufficient favorable growth during treatment will make it difficult to correct the skeletal malrelationship or significantly improve the facial profile. The case report presents the treatment of a patient with a Class II, Division 1 malocclusion with severe overjet and a hyperdivergent growth pattern.

Aim: To evaluate the Bolton ratios in Brazilians with natural, normal occlusions.

Methods: Thirty-five dental casts of Brazilian Caucasians with a natural, normal occlusion from the files of the Postgraduate Program in Orthodontics of the Methodist University of São Paulo were scanned in three dimensions. On the scanned images, the greatest mesiodistal distance of each tooth from right first molar to left first molar was measured with Geomagic Studio 5 software. The Bolton ratios were then calculated.

Results: The anterior ratio amounted to 78.66% (SD ± 2.72) and the total ratio to 91.58% (SD ± 2.20).

Conclusion: The anterior, but not the overall, ratio was significantly different from the ratio suggested by Bolton.