World journal of orthodontics最新文献

Maxillary canines and first molars are the most common ectopic teeth in young people. Ectopic buccal eruption of maxillary canines is strongly associated with lack of space or crowding in the dental arch. This report demonstrates the management of a buccally erupted maxillary canine in an 11-year, 8-month-old boy without sufficient space. The patient had a mostly dental Class II occlusion and was in the late mixed dentition, and the root development of his canines was consistent with his dental age. To correct the distal occlusion and gain space in the maxillary arch for the eruption of both canines, the patient received cervical headgear. To guide the maxillary left canine into occlusion, it was surgically exposed and a modified utility arch inserted. The result of this approach proves that a custom-designed utility arch allows the distal movement of a buccally displaced canine, while at the same time increasing the maxillary arch length.

When patients of differing ethnicities are treated with one bracket system, negative consequences for the occlusion can result. This study investigated the crown angulation and inclination on study casts of 60 Northern Thais (30 males and 30 females) with a good occlusion. In all study casts, each tooth (except the third molars) was evaluated with the orthodontic Torque Angulation Device (TAD) twice on the right side; this was also performed twice on the left side. The mean of the two evaluations was used for the statistical analysis. The means of the males and females were compared with the independent Student t test. The results were that the crown angulation of the mandibular first and second molars was significantly higher in females (P<.01) and that the crown inclination of all teeth did not differ between the two sexes.

A combined periodontal and orthodontic treatment demands a detailed evaluation in both specialties, particularly when the periodontium is reduced. This is especially true for adult patients, but young patients can also suffer from advanced periodontitis. This article describes combined periodontal and orthodontic therapy in a young patient with severe localized and aggressive periodontitis, tooth crown abnormalities, and missing maxillary second premolars. Periodontal treatment was carried out. Once attachment gain and bone stability were confirmed, orthodontic therapy commenced. It lasted 32 months, during which segmented mechanics and only light forces were used. The result of this intervention was satisfactory, and long-term stability (9 years) with periodontal maintenance was achieved.

Aim: To evaluate the frictional forces generated by ceramic- (Opal, Ultradent) and glass-fiber-reinforced polycarbonate self-ligating brackets (Oyster, Gestenco) and compare the effectiveness of these ligatureless systems with glass-fiber-reinforced polycarbonate conventional brackets (Blonde, Gestenco). The hypothesis is that there is no difference between frictional forces generated by ceramic- and glass-fiber-reinforced polycarbonate self-ligating and glass-fiber-reinforced polycarbonate conventional brackets.

Methods: Twelve preadjusted 0.022 3 0.028-inch maxillary canine brackets were tested, divided into three groups: Opal, Oyster, and Blonde. Frictional tests were conducted with the Emic DL 10000 testing machine with a 20 N loadcell for 40 seconds at a 0.5 cm/min speed. Each bracket-wire combination was tested five times. The data generated were analyzed by parametric analysis of variance (one-way ANOVA) and Bonferroni tests.

Results: Analysis of variance indicated significant differences for the three groups (P<.01). The frictional forces of the Oyster glass-fiber-reinforced polycarbonate self-ligating brackets were significantly lower (37.0 ± 8.9 cN) than those of the Opal ceramic-reinforced polycarbonate self-ligating brackets (49.5 ± 10.1 cN), while the Blonde glass-fiber-reinforced conventional bracket frictional forces were 105.8 ± 6.4 cN.

Conclusion: Oyster glass-fiber-reinforced polycarbonate brackets produced less friction than Opal ceramic-reinforced polycarbonate brackets. The polycarbonate ligatureless system showed significantly lower frictional forces compared to Blonde conventional polycarbonate brackets tied with elastomeric ligatures. The study rejected the initial hypothesis because there are significant differences of frictional forces among the tested systems.

A 20-year-old woman presented with a labially displaced mandibular right central incisor with severe attrition. Her maxillary dentition was well-aligned, and she had a straight profile. The respective central incisor was extracted. Subsequently, all teeth were aligned and the extraction space was closed with 2D lingual brackets. The result was esthetically pleasing.

Caring for patients with bilateral cleft lips and palates requires an interdisciplinary approach. The treatment of such a patient is described. Therapy comprised maxillary expansion, mini-implant insertion, premaxillary osteotomy, and vomeroplasty, which led to a drastic improvement of the occlusion and facial appearance.

Aim: To determine the malocclusion complexity and orthodontic treatment need in urban Iranian schoolchildren using the Index of Complexity, Outcome, and Need (ICON) and the Index of Orthodontic Treatment Need (IOTN) and to also assess the relationship between these indices.

Methods: The study sample comprised 502 individuals (253 girls and 249 boys, 11 to 14 years of age), of whom one girl and five boys already had an orthodontic appliance at the time of the survey. In those individuals not wearing orthodontic appliances (n=496), the definitive treatment need (ICON>43) and compartments of the ICON were defined and compared between sexes. The Aesthetic Component and Dental Health Component (DHC) of the IOTN were also recorded. Scatter plots and Spearman rank correlation coefficients were used to explore the relationships between the ICON and DHC and the Aesthetic Component (AC) of the IOTN.

Results: According to ICON, DHC (IOTN), and Aesthetic Component (IOTN), 46.6%, 36.1%, and 17.9%, respectively, of the studied children needed orthodontic treatment; however, only 1.1% wore an appliance. In terms of complexity, 26.4% of the studied individuals were considered to have a difficult or very difficult malocclusion. With regard to treatment needs, significant correlations existed between the ICON scores and DHC (IOTN) (r=0.93) and between the ICON scores and the esthetic component (IOTN) (r=0.96). The threshold for treatment need was lower in the ICON than in the IOTN. Of the children who were classified in the borderline category of the IOTN (DHC=3), 52.0% were in need of treatment according to their ICON score (ICON>43). No sex difference was found for treatment need (ICON>43, P>.05) and treatment complexity (P>.05).

Conclusion: According to the ICON, 46.6% of the Iranian schoolchildren need orthodontic treatment. ICON is a good substitute for the IOTN, yet it results in a lower treatment-need threshold.

Aim: To assess the relationship between palatal height and width on plaster casts from 33 growing individuals with Class II Division 1 relationships who received orthodontic treatment without extraction.

Methods: The palatal contours in the permanent canine and first molar regions were registered with a digital pantograph before treatment (T1), at the end of treatment (T2), and at least 5 years posttreatment (T3).

Results: The anterior palatal height did not change between T1 and T2, but a significant reduction was observed between T2 and T3. In the posterior palatal region, the height increased between T1 and T2 but not thereafter. No significant transverse changes were found in the canine region between T1 and T2. In the posterior region, however, the width increased significantly between T1 and T2.

Conclusion: Palatal morphology in orthodontically treated Class II patients changed from an initially more triangular into a more square shape due to an increase in height and basal width, as well as a decrease in cervical width.

Aim: To investigate the spontaneous tooth position changes after unilateral extraction of mandibular first molars and the influence on third molar position.

Methods: Panoramic radiographs of 111 individuals (mean age 19 years 8 months) in whom one mandibular first molar was extracted at least 5 years prior. Comparison of all measurements of the control and the affected side was performed by paired Student t test.

Results: The mandibular second molars tipped mesially, whereas the premolars, canines, and incisors moved distally toward the extraction space. Vertical alveolar resorption was significant, particularly in older patients. Mesial inclination of the third molar occurred in only subjects in whom this tooth was completely developed. No significant vertical change of the third molars was observed.

Conclusion: Unilateral extraction of mandibular first molars causes a significant displacement of all teeth of the affected side toward the extraction site and a progressive vertical bone resorption of this area. The closer the teeth are to the extraction site, the more they are affected. No significant changes were observed on third molar vertical position.

Aim: To investigate the effect of a modified tongue crib appliance in Class II Division 1 patients with anterior tongue thrust and mandibular deficiency.

Methods: Twenty-three patients (14 females, 9 males) with a mean age of 10.09 ± 1.02 years, a moderate Class II Division 1 occlusion due to a mandibular deficiency, and a mean overbite of -1.1 ± 0.8 mm were treated with a mandibular tongue crib device. Pre- and posttreatment lateral cephalograms were obtained and traced, and various angular and linear variables were measured. These measurements were compared using the paired t test.

Results: The statistical assessment indicated that SNB, facial angle, B-VL, Pog-VL, and interincisal angle increased significantly. IMPA, 1-SN, ANB, and Wits appraisal were significantly decreased (P<.05). The changes of Jarabak Index, SN-MP, SNA, and Y-axis were not significant. In addition, the overjet was reduced.

Conclusion: During the mixed dentition phase, a tongue crib appliance in the mandible is helpful to impede tongue thrust and stimulate mandibular growth.