Comparison of Jones jig molar distalization appliance with extraoral traction

A New Digital Method to Quantify the Effects Produced by Carriere Motion Appliance

The aim of this study was to analyze a novel digital technique to quantify the distal tooth displacement and derotation angle produced by the Carriere Motion Appliance (CMA). Twenty-one patients with a class II molar and canine relationship underwent orthodontic treatment with CMA. All patients were exposed before (STL1) and after the CMA placement (STL2), submitted to a digital impression, and afterwards, data were uploaded to specific cephalometric software to allow automatic mesh network alignment of the STL digital files. Subsequently, the distal tooth displacement of the upper canines and first upper molars, as well as the derotation angle of the first upper molars were analyzed using the Pearson correlation coefficient (ρ). Repeatability and reproducibility were analyzed using Gage R&R statistical analysis. An increase in canine displacement was correlated with an increase in contralateral canine displacement (ρ = 0.759; p < 0.000). An increase in canine displacement was correlated with an increase in molar displacement (ρ = 0.715; p < 0.001). An increase in upper first molar displacement was correlated with an increase in the contralateral upper first molar displacement (ρ = 0.609; p < 0.003) and the canine displacement (ρ = 0.728; p < 0.001). The distal tooth displacement showed a repeatability of 0.62% and reproducibility of 7.49%, and the derotation angle showed a repeatability of 0.30% and reproducibility of 0.12%. The novel digital measurement technique is a reproducible, repeatable, and accurate method for quantifying the distal tooth displacement of the upper canine and first upper molar, as well as the derotation angle of the first upper molars after using CMA.

Dentoskeletal and soft-tissue changes of class II malocclusion treatment with modified first class appliances: a prospective clinical trial

Background/Objectives

Intraoral distalizers are effective and conservative alternatives for Class II malocclusion treatment. However, the literature is still controversial regarding the effects of using skeletal anchorage in intraoral distalizers with different designs. The aim of this study is to compare dentoskeletal and soft-tissue changes of Class II malocclusion patients treated with three types of First Class (FC) distalizers.

Materials/Methods

The sample of this prospective clinical trial included 30 consecutive patients divided into three groups: G1—FC conventionally anchored; G2—FC skeletally anchored Type 1; G3—FC skeletally anchored Type 2. Each group consisted of 10 patients. Lateral cephalograms were analyzed in two stages: at pre-treatment (T0) and after distalization (T1). The radiographs were digitized and analyzed using the software Dolphin Imaging 11.5. Comparisons of treatment changes between groups (T1–T0) were performed using one-way analysis of variance (ANOVA), followed by the Tukey test.

Results

Patients treated with the conventionally anchored FC showed significantly greater incisors protrusion and labial inclination, second premolars mesial inclination and mesialization than the FCs skeletally anchored. No differences were observed regarding the amount of molar distalization and molar angulation between groups.

Limitations

It can be considered that the limitation of this study lies in its non-randomized design.

Conclusions/Implications

First Class distalizers with conventional and skeletal anchorage are effective alternatives for Class II molar distalization. Distalization associated with indirect skeletal anchorage reduce the undesirable effects observed in the incisors and premolars during distalization when compared to distalization conventionally anchored.

The Application of Pendulum as a Space Regainer in Orthodontic Treatment

Background:

The process of distalization in orthodontic treatment is often very difficult. The most common method is the use of cervical headgear. However, due to poor patient compliance, it leads to poor treatment outcomes. Treatment alternatives that require minimal compliance include Jones jig, magnets, and pendulum.

Objective:

This study aimed to perform distalization of a maxillary molars on a bilateral Class II molar relationship patient with a crowded maxillary arch.

Case Report:

A 10-year-old female with a Class II molar relationship, bilateral posterior crossbite, and nonerupted upper canines was treated with a rapid palatal expander (RPE), pendulum appliance, and fixed appliance. The crowding in the maxillary arch and spacing in the mandibular arch were eliminated, and transverse discrepancies were corrected.

Conclusion:

Pendulum appliance is very effective in creating spaces for the eruption of canines and ectopic premolars. Pendulum appliances have been introduced for a long time and have proven successful for molar distalization and space regainer and require minimal patient cooperation. Like other distalization appliances, distal tipping of the molars and mesial movement of the premolars could be observed.

Distalization in Orthodontics: A Review and Case Series

Distalization is a conservative method that is utilized in orthodontics to gain space by moving posterior teeth distally. It may be combined with other space gaining strategies, such as expansion, or can be used alone. Many methods have been used for distalization. These methods differ significantly in their place, whether to be extraoral or intraoral, site of action in upper and/or lower arch, and cooperation needed by the patient if it is removable or fixed. This review illustrates some of the most commonly used methods for distalization with a brief presentation of three cases that incorporated successful distalization techniques.

Stress distribution patterns in mini-implant and bone in the infra-zygomatic crest region at different angulations: A finite element study

PURPOSE

To evaluate, using the finite element method (FEM), von Mises stress patterns produced both in a mini-implant (MI) and the infra-zygomatic crest region (IZC) at different placement angles and force magnitudes.

MATERIAL AND METHODS

FEM modeling of an infra-zygomatic crest MI, of dimensions 2 mm × 12 mm, was designed and placed in the IZC bone. The MI was inserted at 50°, 60°, 70°, 80°, and 90° angulations to the IZC surface. Simulated orthodontic forces of magnitudes 8, 9, 10, 11, and 12 oz were applied to the MI head. Von Mises stress and magnitude both in the MI and surrounding bone were measured.

RESULTS

Von Mises stress in the MI and bone was maximum at 90°. Least stresses were observed at 50° and 60° angulations. As force magnitude increased, von Mises stress increased linearly. Maximum stresses in the MI and bone were observed when loads were 12 oz and minimum stresses were observed at 8 oz.

CONCLUSION

To achieve optimum primary stability, angles of insertion between 50° and 60° are recommended in the IZC region. Highest von Mises stress values were detected in the MI, followed by cortical and cancellous bone. Also, loading force between 8 and 12 oz exerted stresses below the tolerable threshold of bone and MI. Hence, proper placement of MI in IZC using these findings might provide better biomechanical stability during retraction and may help in preserving the bone-implant interface.

Stability of class II treatment with Pendulum and Jones jig followed by fixed appliances

INTRODUCTION

The present study aimed to evaluate and compare the long-term stability of Class II correction with the Pendulum or Jones jig followed by fixed appliances.

SETTINGS AND SAMPLE POPULATION

Group 1 comprised 20 Class II malocclusion patients with a mean initial age of 13.97 years (SD = 1.57), treated with Pendulum and fixed appliances for a mean period of 4.72 years (SD = 0.98), and mean long-term post-treatment evaluation of 4.72 years (SD = 0.97). Group 2 consisted of 18 Class II patients with a mean initial age of 13.19 years (SD = 1.26), treated with Jones jig and fixed appliances for a mean period of 3.96 years (SD = 0.92). Mean long-term post-treatment time was 5.50 years (SD = 1.57).

METHODS

Lateral cephalograms were evaluated at three stages: initial (T1), final (T2) and long-term post-treatment (T3). Intragroup comparisons were performed with repeated measures ANOVA and Tukey's test and intergroup comparisons with independent t test.

RESULTS

Many treatment changes were observed in both groups. From the long-term post-treatment periods, there was stability for most of the variables. Maxillary second molars and mandibular first molars extruded in the Jones jig group and slightly intruded in the Pendulum appliance group. The nasolabial angle decreased in the Pendulum group and increased in the Jones jig group.

CONCLUSION

The correction of a Class II malocclusion was shown to be stable with similar long-term post-treatment results with Pendulum or Jones jig followed by fixed orthodontic appliances.

Class II malocclusion treatment changes with the Jones jig, Distal jet and First Class appliances

Objective Maxillary molar distalization with intraoral distalizer appliances is a non-extraction orthodontic treatment used to correct molar relationship in patients with Class II malocclusion presenting maxillary dentoalveolar protrusion and minor skeletal discrepancies. This study compares the changes caused by three distalizers with different force systems. Methodology 71 patients, divided into three groups, were included. The Jones jig group (JJG, n=30; 16 male, 14 female, 13.17 years mean age) was treated with the Jones jig for 0.8 years. The Distal jet group (DJG, n=25; 8 male, 17 female, 12.57 years mean age) was treated with the Distal jet for 1.06 years. The First Class group (FCG, n=16; 6 male, 10 female, 12.84 years mean age) was treated with the First Class for 0.69 years. Intergroup treatment changes were compared using one-way ANOVA, followed by post-hoc Tukey's tests. Results Intergroup comparisons showed significantly greater maxillary incisor protrusion in DJG than in FCG (2.56±2.24 mm vs. 0.74±1.39mm, p=0.015). The maxillary first premolars showed progressive and significantly smaller mesial angulation in JJG, FCG and DJG, respectively (14.65±6.31º, 8.43±3.99º, 0.97±3.16º; p<0.001). They also showed greater mesialization in JJG than FCG (3.76±1.46 mm vs. 2.27±1.47 mm, p=0.010), and greater extrusion in DJG compared to JJG (0.90±0.77 mm vs 0.11±0.60 mm, p=0.004). The maxillary second premolars showed progressive and significantly smaller mesial angulation and mesialization in JJG, FCG and DJG, respectively (12.77±5.78º, 3.20±3.94º, -2.12±3.71º and 3.87±1.34 mm, 2.25±1.40 mm, 1.24±1.26 mm, respectively; p<0.001). DJG showed smaller distal angulation of maxillary first molars (-2.14±5.09º vs. -7.73±4.28º and -6.05±3.76º, for the JJG and FCG, respectively; p<0.001) and greater maxillary second molars extrusion (1.17±1.41 mm vs -0.02±1.16 mm and 0.16±1.40 mm, for the JJG and FCG, respectively; p=0.003). Overjet change was significantly larger in DJG compared to FCG (1.79±1.67 mm vs 0.68±0.84; p=0.046). Treatment time was smaller in FCG (0.69±0.22 years vs 0.81±0.33 years and 1.06±0.42 years, comparing it with the JJG and DJG, respectively; p=0.005). Conclusion The three appliances corrected the Class II molar relationship by dentoalveolar changes. The Distal jet produced smaller molar distal angulation than the Jones jig and First Class. The First Class appliance showed less anchorage loss, greater percentage of distalization and shorter treatment time than the Jones jig and Distal jet.

Comparison of the dentoskeletal and soft tissue changes with the cervical headgear and Jones Jig followed by fixed appliances in Class II malocclusion patients: A retrospective study

OBJECTIVE

To retrospectively compare the dentoskeletal and soft tissue changes of patients with Class II malocclusion treated with cervical headgear and Jones Jig appliances, followed by fixed appliances.

MATERIAL AND METHODS

The sample comprised 46 Class II malocclusion patients divided into two groups. Patients with Class II malocclusion based on the ANB angle and plaster model analyses, needing non-extraction orthodontic treatment, absence of mandibular crowding and no previous orthodontic treatment were eligible to be selected. Group 1 consisted of 25 patients treated with cervical headgear (CH) followed by fixed appliances for a mean period of 3.26 years and group 2 consisted of 21 patients treated with the Jones Jig (JJ) appliance for a mean of 4.29 years. Lateral cephalograms were evaluated at the beginning and at the end of orthodontic treatment. For intergroup comparisons, t and Mann-Whitney tests were performed.

RESULTS

The cervical headgear group produced significantly greater maxillary anterior displacement restriction (SNA; CH: -0.97°±1.33; JJ: 0.07°±1.73; P=0.025), apical base discrepancy improvement (ANB; CH: -1.52°±1.25; JJ: 0.36°±1.46; P=0.006), FMA reduction (CH: -0.78°±2.68; JJ: 1.07°±2.84; P=0.028) and distal mandibular molar angulation (Md6.PM; CH: 6.97°±3.66; JJ: 2.77°±6.87; P=0.013) than the Jones Jig group.

CONCLUSIONS

Both distalizers followed by fixed appliances were effective to correct Class II malocclusion. The cervical headgear group presented skeletal effects with less treatment time and there were no significant intergroup differences regarding soft tissue changes.

Comparison of dentoskeletal and soft tissue effects of Class II malocclusion treatment with Jones Jig appliance and with maxillary first premolar extractions

Objective:

The aim of this study was to compare the cephalometric changes in Class II division 1 malocclusion patients treated with Jones Jig appliance or with maxillary first premolar extractions.

Methods:

The sample consisted of 88 lateral cephalograms of 44 patients, divided into two groups. Group 1 consisted of 21 patients treated with Jones Jig appliance, with a mean initial age of 12.88 ± 1.23 years and final mean age of 17.18 ± 1.37 years, and a mean treatment time of 4.29 years. Group 2 comprised 23 patients treated with maxillary first premolar extractions, with a mean initial age of 13.59 ± 1.91 years and mean final age of 16.39 ± 1.97 years, and a mean treatment time of 2.8 years. Intergroup treatment changes were compared with t and Mann-Whitney tests.

Results:

Class II correction in G2 (maxillary first premolar extractions) presented significantly greater maxillary retrusion, reduction of anteroposterior apical base discrepancy, smaller increase in the lower anterior face height and significantly greater overjet reduction than G1 (Jones Jig).

Conclusions:

Treatment with maxillary first premolar extractions produced greater overjet reduction, but the two treatment protocols produced similar changes in the soft tissue profile.

Dental, skeletal and soft tissue effects of the Distal Jet appliance: A prospective clinical study

Objective:

This study evaluated the dental, skeletal and soft tissue effects in Class II malocclusion patients treated with Distal Jet appliance, compared to an untreated control group.

Methods:

44 patients with Class II malocclusion were divided into two groups: Group 1 (experimental) - 22 patients, mean age of 12.7 years, treated with the Distal Jet appliance for a mean period of 1.2 years; Group 2 (control) - 22 untreated patients, mean age of 12.2 years, followed by a mean period of 1.2 years. Lateral cephalograms were obtained before treatment (T₀) and at the end of the distalization (T₁).Independent t test was used to identify intergroup differences.

Results:

When compared to control group, the Distal Jet produced a significant increase in mandibular plane angle (0.7 ± 2.0^o). The maxillary second molars presented distal inclination (6.6 ± 3.8^o), distalization (1.1 ± 1.1 mm) and extrusion (1.3 ± 2.1 mm). The maxillary first molars distalized by 1.2 ± 1.4 mm. The maxillary first premolars mesialized by 3.4 ± 1.1 mm. The maxillary incisors showed slight labial tipping of 4.3 ± 4.7^o and were protruded by 2.4 ± 1.7 mm. There were no significant changes in the facial profile. The overjet increased 1.5 ± 1.1 mm and overbite had no significant changes.

Conclusion:

The Distal Jet appliance is effective to distalize the maxillary first molars, but promotes increase in mandibular plane angle, distal inclination, extrusion and distalization of maxillary second molars, mesialization of maxillary first premolars, proclination and protrusion of maxillary incisors, and increase in overjet, when compared to a control group.

Maxillary molar distalization in treatment of angle class II malocclusion growing patients: Uncontrolled clinical trial

OBJECTIVE

This study was conducted to evaluate the clinical effectiveness treatment effects of a simple buccal technique for maxillary molar distalization using direct buccal skeletal anchorage.

MATERIALS AND METHODS

After sample size calculation, fourteen female patients with bilateral Class II molar relationship (age 11-14 years) were selected from the clinic of the Department of Orthodontics, Faculty of Dentistry, Mansoura University, Egypt. After the application of the eligibility criteria, only eleven patients remained to final evaluation. The criteria included: erupted second maxillary molars, mild to moderate maxillary crowding not exceeding 6mm with/without increased overjet and non-extraction treatment in the lower arch. After alignment and levelling, a miniscrew (1. 8mm diameter - 0. 8mm long) was placed buccally between the maxillary second premolar and the first molar in each side. The maxillary molar distalization was done using 250 grams of force produced from NiTi closed coil spring stretched to a buccal miniscrew. Records including cephalometric x-rays and study casts were taken for all patients before and after molar distalization. Statistical evaluation was performed for the data obtained from analysis of cephalometric tracing and cast photocopies.

RESULTS

The maxillary first molars were distalized with a rate of 0. 89±0. 30mm (95% CI 0.76-1.02) (P<0.001) and distalization amount of 4.09±0. 92mm (CI 3.68-4.50) (P<0.001). They were distally tipped by 2.48°±6. 16 (CI -0.26-5.21) (P=0.073) and rotated distopalatally by 11.89°±5.86 with negligible change in their vertical position about 0.11±0.63mm (CI -0.40-0.17) (P=0.411). There was no anchorage loss evident by the distal movement of all the maxillary teeth (P<0.001). Overjet significantly reduced by 0. 86±0. 50 (CI 0.52-1.20) (P=0.004).

CONCLUSIONS

Maxillary molar distalization using a closed coil and buccal miniscrew is an effective and non-compliance dependent technique in a relatively short time.

Comparative Evaluation of Biomechanical Performance of Titanium and Stainless Steel Mini Implants at Different Angulations in Maxilla: A Finite Element Analysis

Objective: To assess and compare the tensions and deformations (stresses and strains) generated after application of two types of forces (traction and torsion) in miniscrews of two different materials (titanium and stainless steel) placed at five different angulations.

Materials and Methods: Three-dimensional models of the posterior maxillary area and the mini-implants were constructed using computer-aided design software program (CATIA P3 V5-6 R2015 B26 / 2016; Dassault Systèmes). Titanium and stainless steel materials were used for miniscrews. The area constructed was in between the maxillary second premolar and first molar. The models with mini-implants were inserted at five different angulations (30°, 45°, 60°, 75° and 90°). Torsional and tractional forces were applied on these implants, and the models were solved using ANSYS 10.0. Stress generated in implant and in the cortical and cancellous bones was evaluated and compared at all the five angulations.

Results: Stress generated in stainless steel mini-implant during torsional and linear force application was less when compared with titanium mini-implant. Also, stress generated in implants of both materials increased as the angle increased from 30° to 90°. Difference in stress generated by stainless steel implant in the cortical bone for both linear and torsional forces was less when compared with titanium implant, whereas for cancellous bone, the difference was insignificant at all the angles.

Conclusion: Irrespective of angles, difference in stress generated in stainless steel implants and titanium implants for both the forces was not significant, and hence, stainless steel implants can be used effectively in a clinical setting.

Stress distribution in maxillary first molar periodontium using straight pull headgear with vertical and horizontal tubes: A finite element analysis

BACKGROUND

One of the most effective ways for distal movement of molars to treat Class II malocclusion is using extraoral force through a headgear device. The purpose of this study was the comparison of stress distribution in maxillary first molar periodontium using straight pull headgear in vertical and horizontal tubes through finite element method.

MATERIALS AND METHODS

Based on the real geometry model, a basic model of the first molar and maxillary bone was obtained using three-dimensional imaging of the skull. After the geometric modeling of periodontium components through CATIA software and the definition of mechanical properties and element classification, a force of 150 g for each headgear was defined in ABAQUS software. Consequently, Von Mises and Principal stresses were evaluated. The statistical analysis was performed using T-paired and Wilcoxon nonparametric tests.

RESULTS

Extension of areas with Von Mises and Principal stresses utilizing straight pull headgear with a vertical tube was not different from that of using a horizontal tube, but the numerical value of the Von Mises stress in the vertical tube was significantly reduced (P < 0/05). On the other hand, the difference of the principal stress between both tubes was not significant (P > 0/05).

CONCLUSION

Based on the results, when force applied to the straight pull headgear with a vertical tube, Von Mises stress was reduced significantly in comparison with the horizontal tube. Therefore, to correct the mesiolingual movement of the maxillary first molar, vertical headgear tube is recommended.

Bilateral en-masse distalization of maxillary posterior teeth with skeletal anchorage: a case report

Objective:

The aim of this study was to introduce a new method for bilateral distal movement of the entire maxillary posterior segment.

Case report:

A 17-year-old girl with Class I skeletal malocclusion (end-to-end molar relationships, deviated midline and space deficiency for left maxillary canine) was referred for orthodontic treatment. She did not accept maxillary first premolars extraction. A modified Hyrax appliance (Dentaurum Ispringen, Germany) was used for bilateral distalization of maxillary posterior teeth simultaneously. Expansion vector was set anteroposteriorly. Posterior legs of Hyrax were welded to first maxillary molar bands. All posterior teeth on each side consolidated with a segment of 0.017 × 0.025-in stainless steel wire from the buccal side. Anterior legs of Hyrax were bent into eyelet form and attached to the anterior palate with two mini-screws (2 × 10 mm) (Jeil Medical Corporation Seoul, South Korea). Hyrax opening rate was 0.8 mm per month. Lateral cephalometric radiographs were used to evaluate the extent of distal movement. 3.5-mm distalization of posterior maxillary teeth was achieved in five months.

Results:

A nearly bodily distal movement without anchorage loss was obtained.

Conclusion:

The mini-screw-supported modified Hyrax appliance was found to be helpful for achieving en-masse distal movement of maxillary posterior teeth.

Cephalometric effects of the Jones Jig appliance followed by fixed appliances in Class II malocclusion treatment

Objective

The aim of this study was to cephalometrically assess the skeletal and dentoalveolar effects of Class II malocclusion treatment performed with the Jones Jig appliance followed by fixed appliances.

Methods

The sample comprised 25 patients with Class II malocclusion treated with the Jones Jig appliance followed by fixed appliances, at a mean initial age of 12.90 years old. The mean time of the entire orthodontic treatment was 3.89 years. The distalization phase lasted for 0.85 years, after which the fixed appliance was used for 3.04 years. Cephalograms were used at initial (T₁), post-distalization (T₂) and final phases of treatment (T₃). For intragroup comparison of the three phases evaluated, dependent ANOVA and Tukey tests were used.

Results

Jones Jig appliance did not interfere in the maxillary and mandibular component and did not change maxillomandibular relationship. Jones Jig appliance promoted distalization of first molars with anchorage loss, mesialization and significant extrusion of first and second premolars, as well as a significant increase in anterior face height at the end of treatment. The majority of adverse effects that occur during intraoral distalization are subsequently corrected during corrective mechanics. Buccal inclination and protrusion of mandibular incisors were identified. By the end of treatment, correction of overjet and overbite was observed.

Conclusions

Jones Jig appliance promoted distalization of first molars with anchorage loss represented by significant mesial movement and extrusion of first and second premolars, in addition to a significant increase in anterior face height.

Comparative cephalometric study of Class II malocclusion treatment with Pendulum and Jones jig appliances followed by fixed corrective orthodontics

OBJECTIVE

The purpose of this study was to cephalometrically compare the skeletal and dentoalveolar effects in the treatment of Class II malocclusion with Pendulum and Jones jig appliances, followed by fixed corrective orthodontics, and to compare such effects to a control group.

METHODS

The sample was divided into three groups. Group 1: 18 patients treated with Pendulum, Group 2: 25 patients treated with Jones jig, and Group 3: 19 young subjects with untreated Class II malocclusions and initial mean age of 12.88 years. The chi-square test was applied to assess severity and gender distribution. Groups 1 and 2 were compared to the control group by means of the one-way ANOVA and Tukey tests in order to differentiate treatment changes from those occurred by craniofacial growth.

RESULTS

There were no significant changes among the three groups with regard to the components of the maxilla and the mandible, maxillomandibular relationship, cephalometric and tegumental pattern. Buccal tipping of mandibular incisors was significantly greater in the experimental groups and increased mesial angulation of the maxillary second molars was found in the Jones jig group. In the experimental groups, dental relationship, overbite and overjet were corrected.

CONCLUSIONS

It can be stated that the distalization achieved its purpose of correcting the Class II.

Comparison of maxillary molar distalization with an implant-supported distal jet and a traditional tooth-supported distal jet appliance

Aim. To investigate and compare the efficiency of two appliances for molar distalization: the bone-anchored distal screw (DS) and the traditional tooth-supported distal jet (DJ) for molar distalization and anchorage loss. Methods. Tests (18 subjects) were treated with a DS and controls (18 subjects) were treated with a DJ. Lateral cephalograms were obtained before and at the end of molar distalization and were analysed. Shapiro Wilk test, unpaired t-test, and Wilcoxon rank-sum test were applied according to values distribution. The α level was fixed at 0.05. Results. Maxillary first molars were successfully distalized into a Class I relationship in all patients. The mean molar distalization and treatment time were similar in both groups. The DS group exhibited a spontaneous distalization (2.1 ± 0.9 mm) of the first premolar with control of anchorage loss, distal tipping, extrusion, and skeletal changes. Conclusions. The DS is an adequate compliance-free distalizing appliance that can be used safely for the correction of Class II malocclusions. In comparison to the traditional DJ, the DS enables not only a good rate of molar distalization, but also a spontaneous distalization of the first premolars.

Combined treatment with headgear and the Frog appliance for maxillary molar distalization: a randomized controlled trial

Objective

To evaluate the efficiency of the Frog appliance (FA) alone or in combination with headgear for distalizing the maxillary molars.

Methods

Fifty patients (25 males and 25 females) aged 12.6 - 16.7 years who received treatment for Class II malocclusion at the Orthodontic Clinic of Al-Baath University were selected for this study and randomly divided into 2 equal groups. Maxillary molar distalization was achieved using the FA alone (group 1) or a combination of the FA with high-pull headgear worn at night (group 2). Lateral cephalograms were obtained before and after treatment.

Results

The maxillary molars moved distally by 5.51 and 5.93 mm in groups 1 and 2, respectively. Distal movements were associated with axial tipping by 4.96° and 1.25°, and with loss of anchorage by mesial movement of the second maxillary premolars by 2.70 and 0.90 mm in groups 1 and 2, respectively. The combined use of the FA and nighttime high-pull headgear decreased the distalization time and improved the ratio of maxillary molar distalization movement relative to the overall opening space between the first maxillary molars and second premolars.

Conclusions

The FA can effectively distalize the maxillary molars, this distalization associates with some unfavorable changes. Nighttime use of high-pull headgear combined with the FA can reduce these unfavorable changes and improve treatment outcomes.

Dentoskeletal effects of the fast-back molar distalizer followed by fixed appliances

INTRODUCTION

The purpose of this study was to analyze the skeletal and dentoalveolar changes induced by the Fast-Back appliance followed by fixed appliances when compared with untreated Class II controls.

MATERIALS AND METHODS

The treated and untreated samples consisted of 27 subjects each (16 girls and 11 boys in the Fast-Back Group, FBG; 15 girls and 12 boys in the control Group, CG) with mean ages at the start of treatment of 13 years 3 months in the FBG and 13 years 2 months in the CG. Subjects of the FBG were treated during either the pubertal or postpubertal periods. Lateral cephalograms were analyzed at 2 observation periods: before distalization (T1) and after comprehensive orthodontic treatment appliance (T2). The T1-T2 changes in the FBG were contrasted with those in the CG by means of Mann-Whitney U test (p<0.05).

RESULTS

Treatment induced an average correction of molar relationship of 2.4mm. The significant correction of the overjet (2.1mm) was associated with a significant amount of lower incisor proclination (3.8 degrees). A significant extrusion of lower molars (1.8mm) was recorded in the FBG. The FBG showed also a significant increase in total mandibular length (Co-Gn, 2.6mm), a counterclockwise rotation of the palatal plane (1.4 degrees), an increase in anterior facial height (N-Me, 2.7 mm), and in mandibular ramus height (Co-Go, 2.6mm).

CONCLUSIONS

The Fast-Back is an effective appliance for Class II correction during the pubertal or postpubertal periods.

Non-compliance maxillary molar distalizing appliances: an overview of the last decade

OBJECTIVES

To perform a literature review focusing on the use of non-compliance intraoral appliances for molar distalization therapy.

MATERIALS AND METHODS

A literature search ranged from January 1999 to December 2009 in order to describe dento-alveolar changes and skeletal vertical modifications following the use of conventional anchorage intraoral distalizing appliances. The quality of the retrieved studies was ranked on a 12-points scale, from low to high quality.

RESULTS

A total of 214 articles were found and only 24 were considered eligible for the critical examination. Maxillary first molar distalization ranged from 6.4mm to 0.5mm with a concomitant distal tipping from 18.5° to bodily distalization. A smaller amount of distal movement and a greater amount of crown tipping can be noted at second molars. Premolar anchorage loss and incisor proclination represent an unavoidable side-effect and ranged from 4.33 mm to 0.73 mm and from 13.7° to 0.6° respectively. Skeletal vertical modifications were noted. Increase in vertical facial dimension ranged from 1.5° to -1.8° and lower anterior facial height ranged from an increase of 3.2 to a decrease of 0.6 mm. The assessment of study quality showed that 19 studies were of low quality, 3 of medium quality and 2 of medium-high quality.

CONCLUSIONS

Maxillary molar distalization can be effectively performed with the use of noncompliance intraoral appliances. As a consequence, premolar anchorage loss, incisor proclination and a slight increase in vertical facial dimension can occur. Because of the lack of high-quality studies the findings of this review should be carefully interpreted.

Changes in stress distribution of orthodontic miniscrews and surrounding bone evaluated by 3-dimensional finite element analysis

INTRODUCTION

Miniscrews can be used to provide absolute anchorage during orthodontic treatment. If we could obtain the optimum design or shape of the miniscrew, we might be able to reduce its size and lessen the chance of root contact. In addition, miniscrews are placed at several angles, and orthodontic forces are applied in various directions for clinical requirements. In this study, we used finite element analysis to investigate changes in stress distribution at the supporting bone and miniscrew by changing the angle and the shape of the miniscrew and the direction of force.

METHODS

Three types of miniscrews (cylindrical pin, helical thread, and nonhelical thread) were designed and placed in 2 types of supporting bone (cancellous and cortical). The miniscrews were inclined at 30°, 40°, 45°, 50°, 60°, 70°, 80°, and 90° to the surface of the supporting bone. A force of 2N was applied in 3 directions.

RESULTS

Significantly lower maximum stress was observed in the cancellous bone compared with the cortical bone. By changing the implantation angle, the ranges of the maximum stress distribution at the supporting bone were 9.46 to 14.8 MPa in the pin type, and 17.8 to 75.2 MPa in the helical thread type. On the other hand, the ranges of the maximum stress distribution at the titanium element were 26.8 to 92.8 MPa in the pin type, and 121 to 382 MPa in the helical thread type. According to the migration length of the threads in the nonhelical type, the maximum stresses were 19.9 to 113 MPa at the bone, and 151 to 313 MPa at the titanium element. By changing the angle of rotation in the helical thread type, the maximum stress distributions were 25.4 to 125 MPa at the bone, and 149 to 426 MPa at the titanium element. Furthermore, the maximum stress varied at each angle according to the direction of the applied load.

CONCLUSIONS

From our results, the maximum stresses observed in all analyzed types and shapes of miniscrews were under the yield stress of pure titanium and cortical bone. This indicates that the miniscrews in this study have enough strength to resist most orthodontic loads.

Effects of maxillary molar distalization with Zygoma-Gear Appliance

OBJECTIVE

To evaluate the dentoalveolar, skeletal, and soft tissue effects of the Zygoma-Gear Appliance (ZGA) when used for bilateral distalization of the maxillary molars.

MATERIALS AND METHODS

The study group included 15 patients (mean age, 15.87 ± 1.09 years; range: 14-18 years) treated with the ZGA system supported with zygomatic anchorage miniplates. The changes due to the distalization were evaluated from the lateral cephalometric films taken before and after distalization by means of a paired t-test.

RESULTS

The mean treatment period required to achieve a Class I molar relationship was 5.21 months. The distalization amount of the maxillary molars was 4.37 ± 2.15 mm (P < .001), and, thus, the rate for the distal movement of the molars was 0.84 mm per month. Maxillary first molars showed a slight intrusion (0.50 mm) (P > .05), while distal tipping was only 3.30° ± 2.31° (P > .05). Furthermore, there was a decrease in overjet (-0.50 mm) (P > .05), indicating that there was no anchorage loss with use of the ZGA.

CONCLUSIONS

Maxillary molar distalization without anchorage loss can be achieved in a short time with ZGA.

Noncompliance maxillary molar distalization with the first class appliance: a randomized controlled trial

INTRODUCTION

The aim of this study was to evaluate the treatment effects of the First Class Appliance (FCA) (Leone, Firenze, Italy) used for the distalization of maxillary first molars in patients with Class II malocclusion and mixed dentition.

METHODS

According to the results of the power analysis for sample size calculation, 32 consecutive patients with bilateral Class II molar relationships were initially included in the study. After application of the inclusion and exclusion criteria, 26 patients remained for the final evaluation. They were randomized into 2 groups: treatment group (n = 15) and untreated control group (n = 11). Lateral cephalograms and dental casts were obtained before and immediately after distalization for the treatment group, and initially and approximately 22 weeks later for the control group. Statistical evaluation of the variables included the mixed 2-way analysis of variance at P <0.05. The method error was also estimated.

RESULTS

The mean treatment period to achieve a full Class I molar relationship was 17.2 weeks. Analysis of the data showed significant distalization of the maxillary first molars produced by the FCA (mean: 4.00 mm) when compared with the untreated group (mean: 0.95 mm). The rate of molar movement was 1.00 mm per month, which, however, was associated with distal tipping of the first molars (8.56 degrees ) and anchorage loss of the anterior dental unit in terms of overjet increase (0.68 mm), and mesial movement (1.86 mm) and inclination (1.85 degrees ) of the first premolars or first deciduous molars. The maxillary first molars also moved buccally (1.37 mm), but no significant distal rotation occurred.

CONCLUSIONS

The FCA is an efficient noncompliance appliance to distalize molars in the mixed dentition without distal rotations. However, these movements are associated with distal molar tipping and anchorage loss of the anterior teeth.

Molar distalization with a pendulum appliance K-loop combination

SUMMARY

The aim of this study was to evaluate the dentoalveolar effects of a pendulum appliance supported buccally by a K-loop, and to compare these with a cervical headgear (CHG) group. The records of 30 patients with skeletal Class I and dental Class II malocclusions were divided in to two groups: Patients in group 1 (seven females and eight males; mean age, 15.0 +/- 3.4 years) were treated with a pendulum appliance supported with a K-loop buccally, while in group 2 (10 females and 5 males; mean age, 14.2 +/- 2.9 years), the patients were treated with CHG. Standardized lateral cephalograms and study models were taken at the beginning of treatment (T0) and at the end of distal molar movement (T1). T0-T1 changes within the groups were analysed with a paired t-test, and between the groups with a t-test. The mean amount of distalization was 4.53 +/- 1.46 mm in group 1 and 2.23 +/- 1.68 mm in group 2. The mean amount of distal tipping for group 1 was 5.13 +/- 4.90 degrees; the mean amount of mesial tipping for group 2 was 0.80 +/- 2.27 degrees. Intrusion and mesiobuccal rotation of the maxillary molars were achieved in both groups. In group 1, the amount of labial protrusion and tipping of the maxillary incisors was not statistically significant. In group 2, palatoversion and retrusion of the maxillary incisors was statistically significant (P < 0.01 and P < 0.001, respectively). The two major disadvantages of intraoral appliances, which are distal tipping of molars and loss of anchorage at the anterior teeth, were significantly decreased with the use of a pendulum appliance K-loop combination.

Distal movement of maxillary molars using miniscrew anchorage in the buccal interradicular region

OBJECTIVE

To quantify the treatment effects of interradicular miniscrew anchorage and to confirm the validity of the clinical usage of interradicular miniscrews in the distal movement of maxillary molars in nonextraction treatment.

MATERIALS AND METHODS

Twenty-four maxillary molars were moved to the distal using miniscrews placed in the interradicular space between the second premolar and the first molar at an oblique angle of 20 to 30 degrees to the long axis of the proximal tooth. The teeth were evaluated as to how the molars were moved to the distal with the use of lateral cephalograms and dental casts.

RESULTS

Maxillary molars were moved to the distal by 2.8 mm with distal tipping of 4.8 degrees and intruded by 0.6 mm. Maxillary incisors were moved to the distal by 2.7 mm with palatal tipping of 4.3 degrees. Molar extrusion and/or consequent mandibular rotation was not observed in any patient.

CONCLUSION

Miniscrews placed in the maxillary interradicular space provide successful molar distal movement of 2.8 mm without patient compliance and with no undesirable side effects such as incisor proclination, clockwise mandibular rotation, or root resorption.

Comparative distalization effects of Jones jig and pendulum appliances

INTRODUCTION

In this study, we compared the dentoalveolar changes of Class II patients treated with Jones jig and pendulum appliances.

METHODS

The experimental group comprised 40 Class II malocclusion subjects, divided into 2 groups: group 1 consisted of 20 patients (11 boys, 9 girls) at a mean pretreatment age of 13.17 years, treated with the Jones jig appliance for 0.91 years; group 2 comprised 20 patients (8 boys, 12 girls) at a mean pretreatment age of 13.98 years, treated with the pendulum appliance for 1.18 years. Only active treatment time of molar distalization was evaluated in the predistalization and postdistalization lateral cephalograms. Molar, second premolar, and incisor angular and linear variables were obtained. The intergroup treatment changes in these variables were compared with independent t tests.

RESULTS

The maxillary second premolars showed greater mesial tipping and extrusion in the Jones jig group, indicating more anchorage loss during molar distalization with this appliance. The amounts and the monthly rates of molar distalization were similar in both groups.

CONCLUSIONS

The Jones jig group showed greater mesial tipping and extrusion of the maxillary second premolars. The mean amounts and the monthly rates of first molar distalization were similar in both groups.

Soft tissue profile after distal molar movement with a pendulum K-loop appliance versus cervical headgear

OBJECTIVE

To evaluate the soft tissue changes associated with the pendulum appliance that was supported with a K-loop buccally and to compare these treatment changes with a cervical headgear group.

MATERIALS AND METHODS

The records of 30 patients having skeletal Class I, dental Class II malocclusions were divided to two groups. Group 1 consisted of 7 girls, 8 boys (mean age, 15.0 +/- 3.4 years), and Group 2 consisted of 10 girls, 5 boys (mean age 14.2 +/- 2.9 years). The first group was treated with a pendulum appliance that was supported with a K-loop buccally, and the second group was treated with cervical headgear. Lateral cephalograms were taken at the beginning of treatment and at the end of distal molar movement. Treatment changes within the groups were analyzed using the paired t-test, and between group changes were analyzed with the independent t-test.

RESULTS

The results showed that the pendulum/K-loop appliance had no significant effect on skeletal and dental variables and soft tissue A point, upper lip thickness, and sagittal upper lip position relative to the E plane. A significant difference for the change in Vp-Ls distance was found in patients in the pendulum/K-loop group (P < .05). Patients in the cervical headgear group showed significant retrusion in skeletal, dental, and soft tissue measurements (P < .05).

CONCLUSIONS

The pendulum/K-loop appliance produces distal molar movement without causing any significant changes in the sagittal or vertical positions of either the jaw or the soft tissue profile.

Role of the friction free distalize appliance (2FDA)PAT in the molar distalization: photoelastic analysis and alkaline-phosphatase (ALP) activity on first molar and bicuspid

Maxillary molar distalization is an increasingly popular option for the resolution of Class II malocclusions. This study describes the effects of one particular molar distalizing appliance, the Friction Free Distalize Appliance (2FDA), in a sample of 20 consecutively treated and growing patients to verify the osteoblastic activity in the compression and traction sites of both the molars and the bicuspids when used as the anchorage teeth. The 2FDA appliances were constructed utilizing a Nickel Titanium open coil spring of 200 gr force in order to distalize the maxillary first molar. The reaction force was controlled utilizing the principle of low/free friction. The results show that the resin around the root of the bicuspid did not discolour at all, which indicates an absence of a force load. On the other hand, on the molar, the resin around the root of the molar became discoloured due to the fact that an orthodontic force was involved with the tooth. To better understand whether the quantity of force that reached the tooth was able to produce osteoblastic recruitment in the sites of tension of the molar and the bicuspid, we quantified an enzyme, the alkaline phosphatase (ALP), present. This measurement allowed us to verify a regular increase of the ALP on the site of molar traction. We also elaborated a mathematical model to evaluate the quantity of force of reaction that produces the device on the bicuspid. Such force results as being 8.34 grams which equals half the pressure of the capillaries of the parodontal ligament (18 grams). The 2FDA appliance compares favourably with other intra-oral distalization devices for the resolution of patients with Class II malocclusions, and is the only distalizing appliance that does not determine osteoclastic/osteoblastic recruitment on the anchorage tooth.

Distal Movement of Maxillary Molars Using a Lever-arm and Mini-implant System

Recently, many studies have been reported on distal molar movement using temporary anchorage devices. However, the side effects of distal movement, such as distal tipping, rotation, or extrusion, are still unsolved. This article describes the use of the lever-arm and mini-implant system for controlled distal movement of maxillary molars and two clinical cases in which patients were treated with this system. Mini implants are needed to control the point of force application in the posterior area with no anchorage loss. When the length of the lever arm and the position of the mini implant are adjusted, the desired line of action of the distal force is determined with respect to the center of resistance of maxillary molars. The lever-arm and mini-implant system is useful not only for absolute anchorage, but also for three-dimensional control during distal movement of the upper molars.

Dentoskeletal changes induced by the Jasper jumper and cervical headgear appliances followed by fixed orthodontic treatment

INTRODUCTION The objective of this controlled clinical study was to compare the dentoskeletal effects of the Jasper jumper with those of cervical headgear, when both are used with edgewise appliances to correct Class II Division 1 malocclusion.

METHODS

Lateral cephalograms of 75 patients were divided into 3 groups of 25. The control group included untreated Class II children with an initial mean age of 11.82 years (range, 9.35-14.84 years); they were followed without treatment for a mean period of 1.95 years (range, 0.90-3.95 years). The Jasper jumper group had an initial mean age of 11.86 years (range, 9.45-14.94 years); they were treated for a mean period of 1.96 years (range, 0.93-3.98 years). The cervical headgear group had an initial mean age of 12.29 years (range, 9.95-15.24 years); they were treated for an average of 1.88 years (range, 0.95-3.95 years). Comparison of the initial measurements showed that the 3 groups were similar at pretreatment, thus allowing direct comparisons. Analysis of variance (ANOVA) and the Tukey test were applied for comparison of the groups.

RESULTS

Different appliances yielded specific effects on several components (skeletal and dentoalveolar) evaluated. Anterior maxillary growth was significantly restricted by the cervical headgear. Mandibular growth was similar in all 3 groups, although it was slightly greater in the Jasper jumper group. The experimental groups had similar improvements in maxillomandibular relationshipd. The pattern of craniofacial growth was not significantly different between groups. The most significant effect on the maxillary dentoalveolar component was retrusion of the maxillary incisors by the cervical headgear. The effects observed for the Jasper jumper group were primarily related to the mandibular dentoalveolar component, including labial tipping and protrusion of the mandibular incisors, and mesial movement and extrusion of the mandibular molars compared with the control group.

CONCLUSIONS

The headgear appliance corrected the Class II malocclusion mostly by anterior maxillary restriction and maxillary dentoalveolar effects. Correction of the Class II malocclusion with the Jasper jumper appliance was largely due to mandibular dentoalveolar effects rather than skeletal effects.

Osseointegrated implants with pendulum springs for maxillary molar distalization: A cephalometric study

INTRODUCTION

Maxillary molar distalization is a common treatment approach for patients with Class II malocclusions who do not require extractions. Despite the many advantages of pendulum appliances, the maxillary incisors and premolars tend to shift mesially as the maxillary molars move distally. The purpose of this study was to investigate anchorage loss in patients treated with palatal osseointegrated implants combined with pendulum springs.

METHODS

Pretreatment and posttreatment lateral cephalometric films of 30 consecutively treated patients were examined. One group (n = 15) had been treated with conventional pendulum appliances, and the other group (n = 15) was treated with palatal osseointegrated implants combined with pendulum springs.

RESULTS

In the pendulum group, significant distal tipping of the maxillary first molars and mesial tipping of the maxillary premolars were noted. Distalization of the maxillary first molars, mesialization of the maxillary first premolars, and proclination of the maxillary left central incisor were significant in the linear measurements. In the implant group, the distal tipping of the maxillary first molars and first premolars and the increases in SNGoGn, FMA, Na Me, and Na ANS were significant. Intergroup comparisons showed that changes in the maxillary first premolars, maxillary central incisors, and vertical measurements were significant.

CONCLUSIONS

The use of palatal osseointegrated implants is reliable and provides absolute anchorage.

Sagittal, vertical, and transverse changes consequent to maxillary molar distalization with the pendulum appliance

INTRODUCTION

The purpose of this study was to evaluate the skeletal and dental changes in patients who underwent distalization of their maxillary molars with pendulum appliances.

METHODS

The sample consisted of 31 patients (initial mean age, 14.58 years) with Angle Class II molar relationships and all permanent teeth up to the second molars. The maxillary molars were distalized with pendulum appliances for a mean period of 5.87 months. Lateral cephalograms, 45 degrees oblique radiographs, and dental casts were obtained before and after distalization. Changes produced by the pendulum appliance were analyzed with paired t tests.

RESULTS

Maxillary first molar distalization accounted for 63.5% of the space opening; mesial movement of the maxillary first premolars contributed 36.5% of the space. The mean space opening on lateral cephalograms was 7.25 mm, and the rate of molar movement was 1.23 mm per month. The mean distalization of the maxillary molars was 4.6 mm, with a mean distal crown tipping of 18.5 degrees The maxillary molars experienced expansion, with a smaller effect on the first molars than on the second molars. The pendulum appliance produced symmetrical expansion, with a rate of 1.04 mm per month on the right and 1.10 mm per month on the left.

CONCLUSIONS

The pendulum appliance is effective for distalization of the maxillary molars and the establishment of a Class I molar relationship in a relatively short time. However, caution is needed to control collateral effects, including mesial movement of the first premolars and distal tipping of the molar crowns.

Dentoalveolar and skeletal changes associated with the pendulum appliance followed by fixed orthodontic treatment

INTRODUCTION

This prospective clinical study analyzed the distalization of maxillary molars achieved by the pendulum appliance and its effect on the anchorage teeth during and after fixed orthodontic treatment.

METHODS

Lateral cephalograms of 22 adolescents (15 girls, 7 boys) taken pretreatment, after distalization, after leveling and aligning, and after fixed orthodontic treatment were evaluated. The initial mean age was 14.5 years (SD = 1.80). The mean time for distalization of the maxillary molars was 5.85 months (SD = 1.82), and the total treatment time was 3.61 years (SD = 1.83).

RESULTS

The pendulum appliance moved the maxillary molars distally, but with significant distal inclination, protrusion of the anterior teeth, and increase in lower anterior facial height (LAFH) due to the clockwise mandibular rotation. After fixed orthodontic treatment, the maxillary incisors and the maxillary first premolars and first molars were returned to their pretreatment anteroposterior positions. Thus, at postdistalization, there was 2.1 mm of protrusion of the maxillary first molars, despite the anchorage reinforcement (Nance button and cervical headgear worn at night during fixed appliance therapy). However, at the end of treatment, all patients had Class I molar relationships.

CONCLUSIONS

The pendulum appliance followed by fixed orthodontic treatment corrected the Class II sagittal relationship, especially due to the dentoalveolar changes secondary to the spontaneous mandibular growth in the anterior direction during fixed appliance treatment.

Effects of a segmented removable appliance in molar distalization

The aim of the present investigation was to evaluate the skeletal and dentoalveolar treatment effects of a segmented removable appliance [removable molar distalizer (RMD)] for molar distalization. The study was conducted on 28 patients (12 females and 16 males), with a mean age of 11.8 years. All presented with a skeletal Class I malocclusion and a bilateral dental Class II molar relationship. The pre- and post-distalization records included lateral head films, study models and standard photographs. The findings were evaluated with a paired samples t-test. The average maxillary first molar distalization with the RMD was 3.98 mm, with 4.61 degrees of distal tipping. The maxillary second premolars drifted distally 2.13 mm on average with 1.54 degrees of distal tipping, while the maxillary first premolars showed 1.23 mm of mesial movement and 1.98 degrees of mesial tipping. The incisors protruded 1.09 mm with 1.27 degrees of labial tipping. The RMD was effective in distal molar movement and all patients attained a bilateral Class I molar relationship in an average period of 4.5 months. Hygiene problems and mucosal irritations, frequently found with fixed intraoral distalization techniques, were not observed during the distalization period.

A comparison of two intraoral molar distalization appliances: Distal jet versus pendulum

INTRODUCTION

This study compared the dentoalveolar and skeletal effects on Class II malocclusions of the distal jet with concurrent full fixed appliances and the pendulum appliance both followed by fixed appliances.

METHODS

The 2 samples each consisted of 32 subjects (19 girls and 13 boys) with mean ages at the start of treatment of 12 years 3 months in the distal jet group and 12 years 6 months in the pendulum group. The durations of the distalization phase of treatment were 10 months in the distal jet group and 7 months in the pendulum group, and the durations of the second phase of treatment with fixed appliances were 18 months in the distal jet group and 24 months in the pendulum group. Lateral cephalograms were analyzed at 3 observation times: before treatment, after distalization, and after orthodontic treatment.

RESULTS

During molar distalization, the pendulum subjects showed significantly more distal molar movement and significantly less anchorage loss at both the premolars and the maxillary incisors than the distal jet subjects. The distal jet used simultaneously with fixed appliances and the pendulum were equal in their ability to move the molars bodily. Very little change occurred in the inclination of the mandibular plane at the end of the 2-phase treatment (less than 1 degrees ) in both groups. At the end of comprehensive treatment, the maxillary first molars were 0.6 mm mesial to their original positions in the distal jet group and 0.5 mm distal in the pendulum group. Nevertheless, total molar correction was identical in the 2 groups (3.0 mm), and both appliances were equally effective in achieving a Class I molar relationship. Simultaneous edgewise orthodontic treatment during molar distalization in the distal jet group shortened the overall treatment time but produced significant flaring of both maxillary and mandibular incisors at the end of treatment. The impact on the soft tissue profile was minimal with both appliances.

Dentoskeletal effects induced by rapid molar distalization with the first class appliance

The purpose of this study was to evaluate the treatment effects of the first class appliance (FCA; Leone, Firenze, Italy), a new intraoral device for unilateral or bilateral rapid molar distalizaton. A retrospective study was conducted to compare the predistalization and postdistalization cephalograms of 17 patients (10 male, 7 female) with Class II malocclusions treated with the FCA. Mean age at the start of treatment was 13 years 4 months. The FCA produced rapid molar distalization, and the bilateral Class II molar relationship was corrected in 2.4 months, on average. Maxillary molar distalization contributed to 70% of the space created anterior to the first molars; 30% of the space was due to reciprocal anchorage loss of the maxillary second premolars. The maxillary first molars showed a significant distalization of 4.0 mm, associated with a significant distal axial incline of 4.6 degrees and a significant extrusion of 1.2 mm. As for anchorage loss, the second premolars exhibited a significant mesial movement of 1.7 mm, associated with a significant mesial axial incline of 2.2 degrees and a nonsignificant extrusion of 1.0 mm. In the anterior region, a significant mesial movement of the maxillary incisor of 1.3 mm was associated with a significant incisor proclination (2.6 degrees ) and a significant increase in overjet (1.2 mm). No significant changes in either sagittal or vertical skeletal relationships were observed. The results suggest that the FCA is an efficient and reliable device for distalizing the maxillary permanent first molars.

Upper molar distalization: a critical analysis

Traditional upper molar distalization techniques require patient co-operation with the headgear or elastics. Recently, several different intraoral procedures have been introduced to minimize the need for patient co-operation. This article reviews the appliances currently available for maxillary molar distalization and critically analyses their dentoalveolar and skeletal effects.