Journal of the World Federation of Orthodontists最新文献

Background

This study aimed to investigate unplanned tooth movements in deepbite correction with Invisalign.

Methods

The sample consisted of 34 adult patients with deepbite malocclusion treated with Invisalign. Pretreatment and predicted digital models were exported from ClinCheck software, while the post-treatment model was obtained from an intraoral scan taken at the end of the first set of aligners. Digital models’ superimposition was done using the eModel “Compare” software. Frequency and percentage of occurrence of unplanned linear and angular movements, their magnitude, and direction were then determined. In addition, comparison of unplanned movements was performed between anterior and posterior teeth as well as between linear and angular measurements.

Results

The percentage of unplanned movements ranged from 1.68% to 25.63% in the maxilla and 3.36% to 23.95% in the mandible, being most evident in the first and second molars. Unplanned movements were statistically significantly more frequent in posterior teeth compared with the anterior teeth (P > 0.05). In addition, the frequency of angular movements was statistically significantly higher for each tooth than linear movement (P < 0.05) with a higher mean value. Unplanned mesiodistal movements were the least frequent.

Conclusions

Unplanned linear as well as angular movements were evident in almost all teeth. Unplanned faciolingual inclination and mesiodistal angulation movements were the most frequently observed. Unplanned vertical movements can affect the predictability of deepbite correction and thus merit particular attention in those cases.

Background

Rapid distraction of the periodontal ligament is an effective method to shorten the orthodontic treatment time. The objectives of the present study were to assess the effects of an HYCON device (Adenta GmbH, Germany) on the rate of en masse retraction of the anterior teeth, duration of retraction, anchorage loss, root resorption, and soft tissue changes.

Methods

This study was conducted on 60 female patients aged >18 years, divided randomly into two equal groups: Group 1 comprised 30 patients with HYCON, and group 2 comprised 30 patients with nickel-titanium closed coil springs. Skeletal, dental, and soft tissue changes were evaluated on pre- and post-retraction lateral cephalograms, and the rates of anterior tooth movement and anchorage loss were assessed monthly on the dental casts of the patients. Root resorption was assessed using intraoral periapical radiograph. Student's t test was used for the analysis of parametric data, and the Mann-Whitney U test was used for nonparametric data.

Results

HYCON significantly shortened the retraction duration by 3 months. The rate of anterior teeth retraction was two times faster in group 1, compared with group 2. There was a significant difference in the anchorage loss between the groups in only first 2 months of treatment. Group 2 showed significantly more root resorption and soft tissue changes than group 1 (P < 0.05).

Conclusions

HYCON is an effective device for significantly shortening the duration of retraction with anchorage loss of 2 to 2.5 mm. However, careful monitoring for possible root resorption should be performed.

Background

To quantify the accuracy of Dolphin Imaging software in predicting soft tissue changes of Class II Division 1 incisor relationship treated by all first premolar extraction compared with actual changes.

Methods

Pretreatment and post-treatment lateral cephalograms of 30 young adult subjects (25 females and 5 males; age range of 16 to 21 years) were imported and traced in Dolphin Imaging software (version 11.95). Tracings of actual treatment results and the Dolphin predicted treatment outcome were superimposed to calculate the prediction errors. The mean difference for the Holdaway soft tissue analysis and at each landmark was measured in both the X and Y axes. Paired t test was used to compare the statistical differences in Holdaway soft tissue analysis parameters.

Results

There were significant differences between the predicted and actual values in three parameters of the Holdaway soft tissue analysis (P < 0.05). The overall accuracy of estimation was better in vertical direction than horizontal. Prediction of upper and lower lip landmarks was overestimated horizontally and underestimated vertically, whereas that belonging to chin was underestimated horizontally and overestimated vertically. Soft tissue nasion and soft tissue A-point were most accurately predicted, whereas the least accuracy was found in soft tissue chin region.

Conclusions

Dolphin Imaging Software (version 11.95) can be accurate enough for use in patient communication and education but should be used with caution. It is most accurate in predicting soft tissue changes in the nasion and A-point regions, but least accurate in chin region.

Posterior Crossbite is a common condition resulting because of transverse maxillary deficiency. The growth of the craniofacial complex finishes first in the transverse dimension, followed by sagittal and vertical dimensions. Conventional rapid palatal expansion (RPE) appliances are commonly used to correct transverse maxillary deficiency. Although RPE is efficient in correcting posterior crossbite, it results in dental side effects such as buccal tipping of maxillary molars, root resorption, bone dehiscence, and relapse. Mini-implant-assisted RPE has been introduced to increase the skeletal effects of expansion especially in patients with increased maturation and greater interdigitation of midpalatal suture. This article will review the biomechanics of RPE and mini-implant-assisted RPE. Additionally, the different designs of MARPE and the long-term clinical effects of expansion appliances will also be discussed in detail.

Background

To compare dentofacial effects of distalization with miniscrew-supported pendulum and infrazygomatic crest miniscrews.

Methods

The study included 36 patients whose lateral cephalometric radiographs were obtained before (T0) and after (T1) distalization. Patients were divided into two groups according to the treatment methods: 1) distalization with miniscrew-supported pendulum (MSP) (n = 19; 14 girls and 5 boys; mean age 16.9 ± 1.46 years) and 2) distalization with infrazygomatic crest (IZC) miniscrews (n = 17; 8 girls and 9 boys; mean age 17.0 ± 1.68 years). Dental, skeletal and soft tissue measurements were performed on lateral cephalograms taken from individuals.

Results

A significant molar distalization was achieved both in the MSP group (3.52 ± 0.76 mm at 8.71 ± 2.02 months) and the IZC group (3.5 ± 0.74 mm at 9.7 ± 2.5 months) (P < 0.001 for both). Premolar distalization was significantly lower in the MSP group (1.73 ± 1.09 mm) than in the IZC group (2.81 ± 0.79 mm) (P < 0.01). Significant molar tipping was observed in both groups (P < 0.001), while no significant difference was found between the groups (P > 0.05). Retrusion of maxillary incisors were significantly higher in the IZC group (2.75 mm) than in the MSP group (0.98 mm) (P < 0.01). A significant difference was found between the two groups with regard to the changes in overjet and overbite (P < 0.05).

Conclusions

Both distalization methods were found to be effective in achieving a Class I molar relationship in patients with Class II malocclusion.

Background

The disruption of craniofacial developmental pathways during early embryogenesis can lead to conditions such as nonsyndromic cleft lip with or without cleft palate (NSCL/P). Several lines of evidence indicate that inadequate maternal nutrition causes low folate levels during the periconceptional period, resulting in NSCL/P. Although substantial research has been conducted on the possible link between SLC19A1 genetic variants and NSCL/P, the association between SLC19A1 80G>A (rs1051266) and NSCL/P remains unclear. In the present study, the associations of SLC19A1 80G>A with NSCL/P risk were assessed by calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs) by meta-analyses.

Methods

Following the PRISMA guidelines, a meta-analysis was conducted on 10 studies assessing the NSCL/P risk associated with SLC19A1 80G>A variant. To ascertain the degree of relationship between the SLC19A1 80G>A genetic variant and the risk of NSCL/P, data were analyzed in allelic, recessive and dominant genetic models. CI of OR for each study and the pooled data were obtained. All statistical analyses were conducted utilizing the MetaGenyo software tool, which integrates the adjustment of P values for multiple testing through the Bonferroni method.

Results

The pooled analysis showed that SLC19A1 80G>A variant significantly increased the NSCL/P risk in the allelic model (OR 1.39; 95% CI 1.00–1.92), recessive model (OR 1.37; 95% CI 1.03–1.82) and dominant models (OR 1.7; 95% CI 1.05–2.90). Publication bias was not observed.

Conclusions

This study supports that the SLC19A1 80G>A genetic variant is associated with NSCL/P risk.

Objectives

The aim of this study was to assess subjectively and objectively, at which timepoint the patient undergoing fixed orthodontic treatment will have maximum pain during the initiation of orthodontic treatment.

Materials and Method

A total of 22 patients (21 ± 2.7 years, [15 female and 7 male]) requiring extraction of maxillary first premolar participated in the study. Following bonding, an initial archwire of 0.016" NiTi was placed with a distal force of 100 g applied to the canines. The concentration of prostaglandin E2 (PGE2) in the gingival crevicular fluid was assessed at four time points: 1 hour before (T0); 24 hours (T1); 48 hours (T2); 72 hours (T3) after initial archwire placement. The pain intensity was recorded with visual analog scale.

Results

The concentration of PGE2 increased from T0 to T1. The highest concentration was observed at T2 following which there was a mild decline at T3. Statistically significant difference in the PGE2 concentration was observed between T0 to T1 and T1 to T2. The visual analogue scale (VAS) scores increased from T0 to T1. The highest score was observed at T2 followed by a decline at T3. A statistically significant difference in the VAS score was noted between T0 to T1 and T2 to T3. On correlating PGE2 and VAS score, a weak negative correlation was noted between T0 to T1 and no correlation was noted between T1 to T2 and T2 to T3.

Conclusion

The patients experience maximum pain between 24 hours (T1) and 48 hours (T2) following initial archwire placement. The highest concentration of PGE2 and VAS score was observed at 48 hours (T2).