Orthodontic Waves最新文献

Purpose

Decreased upper airway dimensions due to adenoid enlargement may have unfavorable aesthetic and/or functional effects on the soft or hard tissue profile development. The aim of this study was to investigate the associations between adenoid sizes to upper airway size ratio (airway ratio) in the midsagittal plane and various types of soft and hard tissue facial profile convexity.

Materials and methods

251 lateral cephalometric images of pre-orthodontic healthy subjects with age group of 6•12, 13•18, 19•25 and 26•29 years, were collected. They were classified into four subgroups based on the airway ratio (grade 1: <1/4 í 100), (grade 2: 1/4•1/2 í 100), (grade 3:1/2•3/4 í 100) and (grade 4: >3/4 í 100). The radiographs were characterized as convex, normal and concave soft tissue facial profile according to the facial convexity angle. Cephalometric analyses were done using Dolphin imaging computer software 11.95. Kruskal Wallis test was used to evaluate differences between airway ratio and facial morphologies; the mandibular plane angle was compared between airway ratio subgroups by Chi square.

Results

Airway ratio was not significantly different (P = 0.241) between soft tissue facial convexity subgroups and within age subgroups. Mandibular plane angle was in a significant relation within airway ratio (p = 0.028).

Conclusion

There was not any significant relation between decreased upper airway ratios and types of the soft or hard tissue facial profile convexity, however there was a significant relation between upper airway ratios and age subgroups. A significant revers correlation was seen between the mandibular plane angle and nasopharyngeal dimensions.

Objective

To test the null hypotheses that there is no significant difference in the three-dimensional size of the oropharyngeal space or hyoid position when comparing individuals with a normal jaw relationship with individuals with retrognathic mandibles.

Methods

In total, 226 skeletal class I (0.7° ≤ ANB < 4.7°) or class II (ANB > = 4.7°) adolescent patients were examined and categorized into two groups: normal group and retrognathic group. Group classifications were made based on SNA angle, SNB angle, ANB angle, and maxillary length (Ptm-ANS). From the total available cases, 60 subjects met the above classification criteria and had a normo-divergent facial pattern, with 30 cases in each group. Cone beam computed tomography (CBCT) images were collected for each participant and InVivoDental (Anatomage, San Jose, Calif) software was used to analyze 60 CBCT scans. Mimics 17.0 software was used to reconstruct the upper airway, and indices of oropharyngeal airway dimensions and hyoid position were calculated.

Results

The oropharyngeal airway dimensions of adolescent patients in the retrognathic group were smaller than adolescent patients in the normal group. The hyoid was positioned more superior and posterior in the retrognathic group. With decreases in mandibular length and SNB angle, oropharyngeal space volume tended to decrease, the hyoid tended to be more superior and posterior.

Conclusion

The null hypotheses were rejected. Significant differences in the three-dimensional size of the oropharyngeal space or hyoid position when comparing individuals with a normal jaw relationship with individuals with retrognathic mandibles.

Purpose

The purpose of this study was to make a systematic review and meta-analysis of studies investigated the effects of positional factors on the bonding failure of brackets.

Methods

Electronic databases (PubMed, Web of science, Scopus) were searched by 3 independent researchers. Randomized studies comparing maxilla-mandibular region, anterior–posterior segments, and right-left arch were included in the meta-analysis. The odds ratio was used as the effect size. A two-tailed test was performed to compare the factors. Heterogeneity was calculated with the Cochran Q test and I² statistics.

Results

Association was found between bonding failure and dental regions (OR = 1.24, 95% CI: 1.05, 1.46) (p = 0.009) and between bonding failure and anterior–posterior segments, too (OR = 1.96, 95% CI: 1.58, 2.45) (p < 0.001). But, no association was found bonding failure and arch sides (OR = 1.11, 95% CI: 0.96, 1.29) (p = 0.26).

Conclusion

Clinicians should more care, especially when operating in the mandibular region and posterior segment. However, there is no difference between the left and right arch in terms of the loss of the bracket.

Purpose

The aim of this study was to evaluate three-dimensionally the reliability of Beta angle and its validity in different skeletal anteroposterior and vertical malocclusions.

Materials and methods

This is a retrospective cross-sectional study. Two hundred and thirteen pre-treatment Cone-beam Computed Tomography (CBCT) scans (104 males and 109 females) were used in this study. Based on ANB angle, 100 patients were characterized as skeletal Class I (ANB = 2.17 ± 1.1°), 62 as skeletal Class II (ANB = 5.8 ± 1.47°), and 51 as skeletal Class III (ANB = −2.32 ± 2.42°), and subdivided based on the mandibular plane angle (MP/SN) into normodivergent (MP/SN = 32.09 ± 2.31°) and hyperdivergent (MP/SN = 40.45 ± 3.71°) groups. All cephalometric indicators were measured on 3D volumetric images using Anatomage software 5.2. Descriptive statistics and Pearson correlation between all variables irrespective of skeletal Class or growth pattern were performed. p Value of <0.05 was considered significant.

Results

The overall Pearson correlation showed a statistically significant negative correlation (p < 0.001) between ANB and Beta angle (0.856). There was no significant (p < 0.05) difference in the values of Beta angle, B–X and A–X distance for Class I, Class II and Class III malocclusion with normal and vertical growth pattern.

Conclusions

This three dimensional study interprets the stability of Beta angle irrespective of the difference in craniofacial morphology and growth pattern. Beta angle showed a strong correlation with ANB thus, can be used interchangeably in diagnosis of skeletal malocclusion.

Purpose

The objective of this study was to study the difference in upper airway parameters using two different techniques, i.e. with lateral cephalometry vis-a-vis acoustic pharyngometry in skeletal class I and class II subjects and to find any correlation in airway parameters recorded on cephalogram and acoustic pharyngometer.

Materials and methods

Sixty orthodontic patients with average growth pattern (FMA = 22–28°) were divided in to two groups based on sagittal jaw relationship. Pharyngeal airway dimensions were measured by two different techniques, i.e. on lateral cephalogram and acoustic Pharyngometry. The airway dimensions were compared across both the groups using these techniques.

Results

The linear airway parameters and total oropharyngeal area measured on lateral cephalogram (P-value 0.008) were significantly higher in skeletal class I patients. Total oropharyngeal area measured using acoustic pharyngometry was significantly higher in skeletal class I patients (P = 0.009). The average area on lateral cephalogram and on acoustic pharyngometry did not differ significantly in skeletal class I group (P = 0.590). The comparison of average area in skeletal class II malocclusion group on lateral cephalogram and acoustic pharyngometry also did not differ significantly (P = 0.603). The average area on lateral cephalogram obtained by digital planimeter and acoustic pharyngometry did not differ significantly in both the classes of malocclusion (P = 0.405).

Conclusion

The null hypothesis is rejected as there is significant difference in airway dimensions in skeletal class I and class II subjects and there is a positive correlation in airway parameters as recorded on lateral cephalogram and acoustic pharyngometer.

Purpose

The aim of this study was to evaluate the dimensional properties of bone in the anterior maxilla in patients with different vertical skeletal patterns in order to ensure safe placement of temporary anchorage devices.

Materials and methods

Fifty-one CBCT images were divided into three equal groups according to vertical skeletal pattern, based on palatal plane to mandibular plane angle. Cortical bone thickness, alveolar bone thickness and interdental root distance were measured between the teeth in the anterior maxilla at 6 mm and 8 mm apical to the interdental cementoenamel junction.

Results

Cortical bone thickness was significantly different among vertical groups at some sites. Hyper-divergent subjects had thinner cortical bone than hypo-divergent and normo-divergent subjects. All three groups, in the anterior maxilla, cortical bone thickness tended to increase from between central incisors (U1–U1) to between lateral incisor and canine (U2–U3). Alveolar bone thickness was greatest between central and lateral incisors (U1–U2), and the thinnest alveolar bone was at U1–U1 area. Average interdental root distance ranged from 1.33 ± 0.48 mm to 3.43 ± 1.25 mm. The largest and smallest interdental root distances were at U1–U1 and U1–U2 sites, respectively.

Conclusion

Placement of TADs in hyper-divergent subjects should be performed with caution. The suitable site for TADs in the anterior maxilla was between the lateral incisor and canine in all vertical skeletal patterns.

Introduction

Treatment of a case with impacted canines is complex and numerous options are available ranging from disimpaction to forced eruption.

Objective

The objective of this case report was to describe the treatment of a 19-year-old male, with a skeletal Class II, dental Class II Division 1 malocclusion, prognathic maxilla, proclined maxillary incisors, with missing left maxillary central incisor and bilateral mandibular canine impaction.

Methodology

The orthodontic treatment plan included forced eruption of the impacted canines and conversion of maxillary left lateral incisor to central incisor.

Conclusion

Proper diagnosis and implementation of orthodontic biomechanics can minimize the amount of prosthetic and surgical intervention needed in the management of transmigrated canine and smile designing.

Oligodontia, a severe type of hypodontia generally characterized as tooth agenesis of six or more permanent teeth excluding third molars, is known to have a multifactorial etiology and the characteristics of orthodontic patients are not fully understood. The aim of the present study was to investigate the risks of tooth agenesis between tooth types of permanent dentition in orthodontic patients with non-syndromic oligodontia. Panoramic radiographs of 292 orthodontic patients (184 females and 108 males) were obtained from one university-based orthodontic clinic and 79 private orthodontic clinics in Japan. Agenesis of permanent teeth excluding third molars was evaluated. Multiple logistic regression analysis was conducted to evaluate the risk of simultaneous tooth agenesis between all tooth type combinations. Significant symmetry of tooth agenesis was observed for all tooth types. Twenty-six tooth type combinations showed a significantly increased risk of simultaneous tooth agenesis [odds ratios (ORs): 1.99⬜14.51], and 15 tooth type combinations showed a significantly decreased risk of simultaneous tooth agenesis (ORs: 0.11⬜0.56). These findings suggest early detection to establish appropriate multidisciplinary treatment planning and prediction of the risk for tooth agenesis of non-syndromic oligodontia.

Purpose

The presented study utilized an in vitro Orthodontic SIMulator (OSIM) to study how Class II elastic configuration effects the forces and moments acting on maxillary canine teeth when using a straight archwire fixed lingual appliance.

Materials and methods

Maxillary in-Ovation L self-ligating brackets were bonded to anatomically shaped stainless steel teeth on OSIM. A 0.016″ × 0.022″ stainless steel straight lingual archwire was used to provide a relevant arch shape and to position simulated teeth in a passive position. A mandibular typodont was positioned above the OSIM arch in a half cusp Class II malocclusion to serve as attachment points for elastics. Four different elastic configurations were tested: 1. maxillary–buccal to mandibular-buccal; 2. maxillary–lingual to mandibular–lingual; 3. maxillary–buccal to mandibular–lingual; 4. maxillary–lingual to mandibular–buccal. A new 4.5 oz 3/16″ elastic (n = 40 per configuration) was attached to the maxillary canine and mandibular first molar teeth for each trial. Forces and moments at the maxillary canine simulated center of resistance were considered. ANOVA was used to assess the effect of elastic configuration, and pairwise comparisons using Bonferroni correction were conducted to investigate configuration differences.

Results

Of the thirty-four pairwise comparisons, only two were statistically insignificant. Configurations 1, 2, and 4 were found to produce over 1 N of force in the desired distal direction, whereas Configuration 3 was significantly lower at 0.65 N.

Conclusions

Overall, the configuration of Class II elastics had a significant effect on forces and moments at maxillary canine teeth for a simulated straight archwire fixed lingual appliance.

A 23-year-old female patient with lip protrusion and crowding received lingual orthodontic treatment with multi-slotted brackets and preformed straight archwires. After 5 months of alignment and leveling, anterior retraction was performed for 21 months. Final detailing took five months. The appliances were removed 31 months after the start of treatment. With these multi-slotted lingual brackets, treatment progressed in the simplest and most effective way and board-standard finishes were achieved. Furthermore, the use of preformed lingual straight archwires (PLSWs) allowed much more convenient treatment application.