World journal of orthodontics最新文献

Aim: The aim of this study was to evaluate the skeletal and dentoalveolar changes due to treatment with twin block and Thurow appliances in patients with Class II occlusions.

Method: The sample consisted of 19 randomly selected patients in each group, as well as 20 individuals in the control group. All patients were treated during the prepubertal growth spurt for 12 months. Lateral cephalograms were analyzed at the beginning of active treatment and 12 months later. All data were tested with the ANOVA and Bonferroni tests.

Results and conclusion: These tests showed that the twin block promotes a significant increase (P<.001) in the total length of the mandible, as well as an increase in anterior facial height. In contrast, ANB and NAPog were reduced. In both treatment groups, the maxillary incisors retruded significantly (P<.001), although more so in the twin block group. In the Thurow appliance group, the mandibular incisors protruded significantly (P<.001). All other differences between the two treated groups were not significant.

Aim: To compare the dimensions of lateral incisor crowns adjacent to unerupted palatally displaced and nondisplaced permanent maxillary canines.

Methods: The sample consisted of 36 children between 10 and 12 years of age with unerupted maxillary canines. Each presented with a unilaterally palatally displaced (with respect to the lateral incisor) canine. The lateral incisor next to the palatally displaced canine was considered the experimental tooth; the tooth on the contralateral side was considered the control tooth. Measurements were crown width (mesiodistal), thickness (labiopalatal), taper (convergence of the crown toward the incisal edge), taper type, and crown length.

Results: No association was found between the experimental and control lateral incisors for crown width and thickness. However, a significant correlation was found for crown taper (P=.048) and length (P=.01). The experimental lateral incisors had a higher mean crown taper (0.54 mm) than the controls (0.24 mm). The mean crown length was smaller for the experimental lateral incisors (6.74 mm) than the control ones (7.55 mm).

Conclusion: There is a significantly greater possibility of finding lateral incisors with greater crown taper and shorter length next to palatally displaced canines. However, there is no significant difference in crown width or thickness.

Aim: To study the relationship between incisor retraction and soft tissue profile alterations and to identify and quantify the parameters that influence it.

Methods: Pre- and posttreatment lateral cephalograms of 37 Class I and Class II Division 1 Iranian females in whom at least one maxillary premolar was bilaterally extracted were analyzed and compared.

Results: Significant positive correlations were found between retraction of the maxillary and mandibular incisors and posterior movement of the upper lip (r=0.53, P<.001), the lower lip (r=0.63, P<.001), thickness increase of the upper (r=0.59, P<.001) and lower (r=0.69, P<.001) lip, increase of the soft tissue lower anterior face height (r=0.81, P<.001) and lower soft tissue component (r=0.49, P<.001), and an increase of the nasolabial angle (r=0.43, P<.01). The ratio of maxillary incisor to upper lip retraction was 2:1.

Conclusion: In Iranian girls, a strong correlation exists between anterior tooth retraction and the position and configuration of both lips.

Objective: To determine whether Canadian and United States (US) orthodontic programs provide training in treating patients with cleft lip and palate (CLP) and craniofacial anomalies (CFA) and whether residents will treat these patients in their future practices.

Methods: An email with a personalized link to an anonymous, multi-item, online questionnaire was sent to all 54 Canadian and 335 of the approximately 700 US orthodontic residents. The two questions asked were: "Do you plan to include the treatment of CLP and CFA patients in your practice?" and "Does your program contain formal training in treating patients with CLP and CFA?"

Results: A total of 44 Canadian and 136 US residents responded. In Canada, 30% plan to treat patients with CLP and CFA after graduation, 14% said no, 48% said maybe, and 9% were unsure. In the US, 53% said yes, 7% said no, 36% said maybe, and 4% were unsure. When asked if their program offers formal training in the treatment of these patients, 45% of Canadian residents said yes, 34% said no, and 20% were unsure, whereas 82% of US residents said yes, 12% said no, and 5% were unsure.

Conclusion: Most programs in the US and approximately half in Canada provide training in CLP and CFA, and more than half of US and almost one-third of Canadian residents plan to be involved in the care of patients with CLP and CFA, which is considerably less than those receiving training. Orthodontic programs need to increase the number of postgraduate students who are interested in providing care to CLP and CFA patients after becoming orthodontists.

Aim: To establish soft tissue norms using profile angles and esthetic analysis in the South Indian population.

Methods: A clinically effective method is used for accurately placing the esthetic horizontal line on cephalometric radiograph. A series of two vertical lines provides the determinants for the horizontal positions of the soft tissue chin, soft tissue chin thickness, upper lip position and thickness, lower lip, maxillary incisors, and mandibular incisors in relation to the profile. Using these lines, the esthetic analysis is performed on the lateral cephalograms of 90 subjects (38 males and 52 females) of South Indian descent with a well-balanced facial profile and normal occlusion.

Results: A mild convex profile with a mean profile angle of 19.7 ± 2.4 degrees and 19.4 ± 3.2 degrees for males and females, respectively, is esthetically pleasing and encases functionally stable occlusion. There is no statistically significant difference between males and females except for maxillary incisor position.

Conclusion: Mild protrusion of incisors with upper and lower lip fullness is an acceptable treatment outcome.

Aim: Rapid palatal expansion (RPE) is used for treatment of skeletal crossbites. It may be combined with a face mask if the maxilla is to be protracted. Conventional tooth-borne appliances rely on an almost complete dentition to transmit the relatively high forces to the bony structures of the maxilla and midface. In most situations, tooth-borne appliances produce adverse effects such as buccal tipping of the lateral teeth, imposing the risk of recessions and vestibular bone fenestrations. To overcome these drawbacks, an RPE appliance was developed that utilizes mini-implants anteriorly in the palate for skeletal anchorage. Because this device is also attached to the first molars, it can be denominated as a bone- and tooth-borne appliance (hybrid hyrax). The objective of this clinical pilot study was to investigate its dental and skeletal effects.

Methods: RPE was performed in 13 patients (seven females, six males; mean age 11.2 years). In 10 patients with a skeletal Class III occlusion, a face mask was used simultaneously for maxillary protraction. Three-dimensional scans of the individual study models were digitally superimposed for the assessment of the dental effects. Skeletal effects were evaluated by lateral cephalograms taken before and after RPE and protraction.

Results: The time needed to achieve the intended expansion ranged from 4 to 14 days (mean 8.7 ± 3.6 days). The mean expansion in the first premolar/first primary molar region was 6.3 ± 2.9 mm and 5.0 ± 1.5 mm in the first molar region. The Wits appraisal changed from -5.2 ± 1.3 mm to -2.5 ± 1.5 mm (mean improvement 2.7 ± 1.3 mm). The right first molar migrated 0.4 ± 0.6 mm mesially and the left one 0.3 ± 0.2 mm.

Conclusions: The hybrid hyrax is effective for RPE and can be employed especially in patients with reduced anterior dental anchorage. Since most teeth are not in the appliance, regular orthodontic treatment can start early. The combination of the hybrid hyrax with a face mask for maxillary protraction appears to be effective in minimizing mesial migration of the dentition.

The aim of this study was to illustrate how gallium arsenite aluminum diode laser (824 nm) irradiation can reduce postsurgical edema and discomfort and accelerate sutural osseous regeneration after surgically assisted rapid palatal expansion (SARPE). An adult patient with an 8-mm transverse maxillary discrepancy was treated with SARPE. Infrared laser therapy was started on the 7th postoperative day, with a total of eight sessions at intervals of 48 hours. The laser probe spot had a size of 0.2827 cm2 and was positioned in contact with the following (bilateral) points: infraorbital foramen, nasal alar, nasopalatine foramen, median palatal suture at the height of the molars, and transverse palatine suture distal to the second molars. The laser was run in continuous mode with a power of 100 mW and a fluency of 1.5 J/cm2 for 20 seconds at each point. Subsequently, an absence of edema and pain was observed. Further, fast bone regeneration in the median palatal suture could be demonstrated by occlusal radiographs. These findings suggest that laser therapy can accelerate bone regeneration of the median palatal suture in patients who have undergone SARPE.

Aim: To compare the effect of thermocycling on the shear bond strength of brackets bonded using different primers.

Methods: One hundred twenty extracted defect-free premolars were randomly divided into three groups. In all three, Transbond XT was the bonding adhesive of choice. In the control group (I), the standard Transbond primer was used, in group II a fluoride-releasing primer (Reliance fluoride containing light cure bond), and in group III an antimicrobial fluoride-releasing self-etching primer (Clearfil Protect Bond). These three groups were divided into two subgroups of 20 teeth each. In the first subgroups, the teeth were stored in only distilled water for 24 hours, whereas in the second subgroups, they were thermocycled 500 times between 5 degrees C and 55 degrees C. The shear bond strength was determined with a universal testing machine. After bracket failure, the Adhesive Remnant Index (ARI) score was verified. The data were analyzed using two-way analysis of variance, Bonferroni, and chi-square tests.

Results: The group with the antimicrobial fluoride-releasing self-etching primer had a significantly lower shear bond strength than all other groups (P<.05). Thermocycling reduced the shear bond strength in all groups considerably.

Conclusion: The antimicrobial fluoride-releasing self-etching primer performed comparably worse regardless of thermocycling. Brackets attached with self-etching primers demonstrated a shear bond strength after thermocycling approaching the border of acceptable adhesion. Thermocycling changed the ARI scores of the self-etching primer groups from the bracket-adhesive to the enamel-adhesive interface.

Aim: To measure the arch length of sides containing palatally displaced canines and to compare them with those of contralateral sides with normally positioned canines.

Methods: The study sample consisted of 36 children 10 to 12 years of age with unerupted permanent maxillary canines who presented with palatally displaced canines, unilaterally, with respect to the maxillary lateral incisors. The palatal displacement was evaluated using the horizontal tube shift method with periapical radiographs, after the canine cusp tips were found to overlap their adjacent lateral incisors on panoramic radiographs. Arch length was measured on either side from a uniform point on the mesiolingual surface of the permanent first molar to a point on the dental arch that coincided with an anterior extension of the midpalatal raphae. The side that contained the palatally displaced canine was considered experimental, while the contralateral side was the control. The mean, standard deviation, range, and 95% confidence interval values were calculated, and the Student t test was carried out to obtain the P values for the arch lengths.

Results: The mean arch length value from the experimental sides was 31.38 ± 1.98 mm (95% CI 29.30 to 33.45). The mean value from the control sides was 32.86 ± 2.28 mm (95% CI 30.48 to 35.24).

Conclusion: There is a significantly high possibility of finding palatally displaced canines with respect to maxillary lateral incisors on sides with lesser arch lengths compared to the contralateral sides.

Aim: To compare the initial cephalometric characteristics of complete Class II malocclusions treated with nonextraction or with two maxillary premolar extractions and to verify their degree of influence on the occlusal success rate.

Methods: A sample of 84 records from patients with complete Class II malocclusions was divided into two groups. Group 1 consisted of 31 patients treated with nonextraction at an initial mean age of 12.95 years, while group 2 included 53 patients treated with two maxillary premolar extractions at an initial mean age of 13.3 years. Initial and final occlusal statuses were evaluated on dental casts with Grainger's Treatment Priority Index (TPI); the initial cephalometric characteristics were obtained on the pretreatment cephalograms. The initial cephalometric characteristics of the groups were compared by t test. A multiple linear regression analysis was used to evaluate the influence of all variables in the percentage of TPI reduction.

Results: The pretreatment cephalometric characteristics of the two maxillary premolar extraction cases were a greater vertical growth pattern, greater max illary and mandibular incisor protrusion, greater maxillary incisor and molar dentoalveolar heights, and greater upper and lower lip protrusion than the nonextraction group. However, the regression analysis demonstrated that only the extraction protocol was significantly associated with the occlusal success rate in the groups.

Conclusions: It was concluded that the initial cephalometric characteristics of the groups did not influence the occlusal success rate of the two treatment protocols investigated.