World journal of orthodontics最新文献

This is the report of a patient with an anterior four-unit fixed partial denture in whom a screw was used to extrude a too-short abutment tooth. Due to the mini-implant, fewer teeth needed to be bonded, thereby keeping more teeth out of harm's way.

In the past 10 years, self-ligating brackets have captured the interest of many clinicians and enjoyed increasing popularity. These brackets have been developed to overcome the disadvantages of stainless steel or elastomeric ligatures in terms of ergonomics, efficiency, deformation, discoloration, plaque accumulation, and friction. A self-ligating bracket does not require any type of ligature because it is has a mechanical device that opens and closes the edgewise slot. Secure archwire engagement may be accomplished by a built-in clip. Depending on the interaction between the bracket and archwire, self-ligating brackets can be active and passive. The aim of this article is to describe a new active self-ligating bracket system designed to noticeably reduce the amount of friction that normally originates from archwire-slot interaction, particularly during the correction of horizontal and vertical discrepancies.

Aim: To evaluate the effect of a myofunctional appliance--the preorthodontic trainer (POT)--on the perioral and masticatory muscles by electromyography (EMG) in individuals with an Angle Class II, Division 1 malocclusion.

Methods: Twenty children were treated with a POT appliance, which had to be worn every day for 1 hour and overnight. The EMG recordings were made at the beginning and end of POT therapy during maximal clenching, swallowing, and sucking. For statistical evaluation, the Wilcoxon nonparametric test was used at the P<.05 level.

Results: During POT treatment, the EMG value for clenching of the anterior temporal muscle decreased significantly (P<.001). Also, for the mentalis muscle, the EMG value during clenching decreased significantly; for the orbicularis oris muscle, this was true for sucking (P<.05) and clenching (P<.01). For the masseter muscle, all EMG values were decreased during treatment but significantly only for clenching.

Conclusion: During the 6 months of POT treatment, the perioral and masticatory muscles of Class II, Division 1 patients improved significantly.

Aim: To assess the long-term stability of orthodontic treatment and some factors associated to posttreatment changes.

Methods: Six hundred twenty-seven dental casts of 209 patients were examined with the PAR Index at pretreatment (T1), end of treatment (T2), and at long-term follow-up (T3, mean 8.5 years posttreatment). Friedman test and multiple regression analysis at P < .05 were used to evaluate changes among the time points and factors associated with stability.

Results: After orthodontic treatment, the PAR Index improved by 94.2%. No significant change was observed between T2 and T3 (P>.05). However, when the sample was divided into a well- (PAR Index ≠ 3) and a less well-finished (PAR Index >3) group, it was observed that well-finished patients experienced some deterioration (P<.001), whereas the less well-finished ones showed some improvement (P<.05). Even with the deterioration, the well-finished patients still had a better PAR Index at T3 compared to the less well-finished ones. Regression analysis showed that PAR Index at T1 and T2, age at T1, and length of retainer wear had a slight association with occlusal stability (R(2)=0.27). No significant association was observed between stability and length of treatment, length of follow-up, sex, extraction, or third molar status on the other side.

Conclusion: Orthodontic treatment is quite stable. Not so well-finished treatments tend to show some improvement and well-finished ones deteriorate some. Well-finished patients still have better occlusal characteristics. Retention contributes to maintenance of the final orthodontic results.

Aim: To evaluate the shear bond strength of brackets bonded with resin-modified glass-ionomer cement (RMGIC) using various methods of enamel conditioning.

Methods: Forty-five human premolars were randomly divided into five groups. The roots of these teeth were fixed in acrylic resin cylinders, and brackets were bonded to the teeth's crowns using the following material combinations: RMGIC only; RMGIC and corresponding primer; RMGIC, acid etching, and Scotchbond Multipurpose; RMGIC and two-step self-etching primer; and RMGIC and one-step primer. All specimens were submitted to pH cycling for 14 days before shear bond strength was assessed in a universal test machine.

Results: The medians and standard deviations (in MPa) were RMGIC only = 8.34 ± 1.11; RMGIC and corresponding primer = 7.05 ± 2.24; RMGIC, acid etching, and Scotchbond Multipurpose = 7.00 ± 4.79; RMGIC and two-step self-etching primer = 0.54 ± 0.30; and RMGIC and one-step primer = 10.61 ± 4.58. The value for RMGIC and two-step self-etching primer was significantly lower than all other values.

Conclusion: It can be concluded that the tested RMGIC is suitable for bonding orthodontic brackets, even when used by itself. Different enamel preparations do not improve its performance. However, they can worsen its bonding capacity as the combination with the two-step primer system clearly shows.

Aim: To test Ricketts' 1982 hypothesis that facial beauty is measurable by comparing attractive and nonattractive faces of females and males with respect to the presence of the divine proportions.

Methods: The analysis of frontal view facial photos of 90 cover models (50 females, 40 males) from famous fashion magazines and of 34 attractive (29 females, five males) and 34 nonattractive (13 females, 21 males) persons selected from a group of former orthodontic patients was carried out in this study. Based on Ricketts' method, five transverse and seven vertical facial reference distances were measured and compared with the corresponding calculated divine distances expressed in phi-relationships (f=1.618). Furthermore, transverse and vertical facial disproportion indices were created.

Results: For both the models and patients, all the reference distances varied largely from respective divine values. The average deviations ranged from 0.3% to 7.8% in the female groups of models and attractive patients with no difference between them. In the male groups of models and attractive patients, the average deviations ranged from 0.2% to 11.2%. When comparing attractive and nonattractive female, as well as male, patients, deviations from the divine values for all variables were larger in the nonattractive sample.

Conclusion: Attractive individuals have facial proportions closer to the divine values than nonattractive ones. In accordance with the hypothesis of Ricketts, facial beauty is measurable to some degree.

Aim: To quantitatively assess the extent of morphologic changes of the apical root area and root length of maxillary central incisors after orthodontic treatment using digital subtraction radiography (DSR) and to investigate possible contributing parameters.

Methods: The subtracted images of panoramic radiographs of 21 patients before and after orthodontic treatment were evaluated using I/RAS C and Image J software. The retrieved data were analyzed by means of SPSS statistical software, and the method's error was assessed.

Results: There was a small but significant decrease of the root dimensions of the maxillary central incisors at the end of orthodontic treatment. The amount of root resorption was not significantly influenced by sex, age, dentition, malocclusion classification, extraction, overjet, overbite, elastic wear, and number of teeth with resorption as measured by DSR.

Conclusion: DSR of pre- and posttreatment panoramic radiographs was able to confirm minor root resorption of the maxillary central incisors after orthodontic treatment.

This paper describes the Hybrid Orthodontic Treatment System (HOTS), an innovative method used in first premolar extraction cases. It comprises the following three components: (1) a miniscrew, (2) dual-dimension wires, and (3) multiloop edgewise archwires. HOTS consists of four clearly defined treatment steps: (1) setup, (2) leveling, (3) separate but simultaneous anterior and canine teeth retraction, and (4) final adjustment. HOTS achieves a predictable treatment outcome with a shorter treatment time.