Maxillary molar distalization treated with clear aligners combined with mini-implants and angel button using different traction force: a finite element study

OBJECTIVES

To evaluate the biomechanical system of molar distalization with clear aligner therapy (CAT) combined with angel button using interradicular mini-implants (IRMIs) with varying elastic forces.

MATERIALS AND METHODS

FE models including maxilla, complete maxillary dentition, periodontal ligaments (PDL), composite attachments, mini-implants (MI), and dedicated orthodontic aligner, were constructed. Three groups were created in accordance with the sagittal position of MI. Elastic forces (0 N,1 N,1.5 N,2 N) were applied.

RESULTS

CAT without elastics caused labial tipping and intrusion of the anterior teeth. Initial labial tipping and the von Mises stress of the maxillary anterior teeth decreased as the elastic forces increased.

Lower molar distalization using clear aligners: Is it effective? A systematic review

Distalization is one of the most useful movements in orthodontic treatments. The aim of this systematic review is to analyze the effectiveness of lower molar distalization using clear aligner therapy (CAT). An electronic search was made from January 2012 to October 2022 using PubMed, Scopus, and LILACS databases without language limitations. This systematic review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses checklist. The search strategy resulted in 151 studies. A screening was performed to remove duplicates, and all the studies that did not respond to our questions for the title or abstract. Three studies underwent full text analysis. From the evaluation of the studies included in this review, it is possible to state that lower molar distalization is a clinical solution, but it is not a full bodily movement. CAT can provide more specifically a distal tipping movement. This is confirmed analyzing the discrepancy between expected movement and obtained movement. CAT can be considered a valid therapeutic option in patients with dental class III malocclusion, but it is obtained as a tipping movement instead of a body movement. Over-correction should be considered during the planning of the therapy.

Pain Intensity of Skeletally Anchored Maxillary Molar Distalization in Conjunction with Micro-osteoperforations: A Randomized Clinical Trial

Objective To assess pain intensity levels during orthodontic therapy of Class II malocclusion patients undergoing skeletally anchored maxillary molar distalization assisted with different micro-osteoperforation (MOP) approaches. Methods Twenty-seven patients (12 males and 18 females) with a mean age of 16.1 ± 0.3 years were randomized into three equal groups (n=9): Group 1 comprised MOPs on buccal surface, Group 2 comprised MOPs on buccal and palatal surface, and Group 3 comprised the control or no-MOP group. The patients underwent maxillary molar distalization using skeletally anchored distal jet appliance assisted with or without MOPs. The MOPs were applied repeatedly on the buccal and buccal and palatal sides, or no MOP (control). Pain intensity was assessed using a 10 cm visual analog scale after each device activation at 24, 48, 72 hours, and at seven days. Data were analyzed using one-way ANOVA and repeated measures ANOVA for non-paired and paired means. Results Both approaches of buccal and buccal and palatal application of MOPs showed statistically significant (p< 0.01) higher levels of pain intensity after the first activation at 24 hours. Nevertheless, pain intensity levels decreased significantly in both MOP groups and between the two activations. Conclusion The repeated application of MOPs on either the buccal side only or on both buccal and palatal sides during maxillary molar distalization did not affect the levels of pain experienced; however, these levels were reported to be higher than that obtained in the control group. Moreover, it is observed that these pain levels tend to gradually reduce to mild levels over the subsequent days.

Cervical headgear effectiveness in distalizing molars in relation to patient compliance

OBJECTIVES

The purpose of this study was to measure the effectiveness of the cervical headgear for distalizing first permanent maxillary molars in relation to hours of use.

METHODS

This was a one-centre, prospective, clinical study conducted at the Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece. Participants (N = 26; 17 females, 9 males) were patients with no history of orthodontic treatment, no syndromes or clefts, and Angle's Class II malocclusion, where the treatment plan included a cervical headgear. They were instructed to wear the appliance for at least 12 h per day. A TheraMon® microsensor was embedded in the headgear's strap to objectively measure wear-time. To measure tooth movement, pre- and post-treatment digital models were superimposed, using the palate as a reference area; translation and rotation were measured along three axes. Superimposition and movement measurements were made with the Viewbox 4 software.

RESULTS

Average treatment time and headgear wear were 130 days and 55 days, respectively, i.e. 10.1 h/day. During this period, distal movement averaged 1.75 mm with high variability (min 0.2 mm, max 4.5 mm). Distal tipping and rotation had an average of approximately 5 °C. Cumulative headgear wear was significantly correlated with distal movement (r2 = 0.32, P < .002), distal tipping (r2 = 0.27, P < .01), and distal rotation around the long axis of the tooth (r2 = 0.20, P < .05).

CONCLUSION

Compliance is critical for having a successful clinical outcome. Distalization of the molar with a cervical headgear is correlated with the cumulative hours of appliance use, with hours per day being a weaker predictor.

Effect of Different Anchorage Reinforcement Methods on Long-Term Maxillary Whole Arch Distalization with Clear Aligner: A 4D Finite Element Study with Staging Simulation

The objective of this study was to examine how various anchorage methods impact long-term maxillary whole arch distalization using clear aligners (CAs) through an automated staging simulation. Three different anchorage reinforcement methods, namely, Class II elastics, buccal temporary anchorage device (TAD), and palatal TAD, were designed. Orthodontic tooth movement induced by orthodontic forces was simulated using an iterative computation method. Additionally, the automatic adjustment of the CA was simulated through the application of the thermal expansion method. The results indicated that the palatal TAD group had the largest retraction of incisors, followed by the buccal TAD group and the Class II elastic group, while the least was in the control group. The largest distal displacements and efficiency of molar distalization for the first and the second molars were noticed in the palatal TAD group. Arch width increased at the molar and premolar levels in all groups. The FEM results suggested palatal TAD had the best performance considering anterior teeth anchorage maintenance, both sagittally and vertically. However, attention should be paid to the possible increasement of arch width.

Predictability of Dental Distalization with Clear Aligners: A Systematic Review

The current review aims to evaluate the scientific evidence relating to the effectiveness of treatment with clear aligners (CAs) in controlling distalization orthodontic tooth movement. "Orthodontics, aligners" and "distalization" were the search terms used on the Scopus, Web of Science and Pubmed databases with the Boolean operator "AND". The results of the last ten years of research were 146 studies; of these, 19 publications were included for this review. The distalization movement is possible with invisible masks alone, but the risk of losing anchorage in the anterior sectors is very probable. The stability of the results and the reduction of unwanted effects can be guaranteed by the use of skeletal anchoring devices and interproximal enamel reduction (IPR), with which compensations are obtained to reduce the initial overjet. Temporary anchorage devices (TADs) can be used to manage posterior anchorage after distalization of maxillary molars with aligners. This hybrid approach has demonstrated the greatest orthodontic success. TADs are useful aids to provide direct and indirect skeletal anchorage. The opposite effect must be considered when planning dental distalization, especially of the molars, in patients with large overjet, and corrective measures or the use of auxiliaries may be necessary to prevent midcourse corrections. This systematic review provides a critical evidence-based assessment of the predictability of dental distalization with CAs, an ever-evolving orthodontic technique.

Factors influencing the efficacy of invisalign in molar distalization and tooth movement

Introduction: The work aims to establish and analyze the factors influencing the efficacy of Invisalign in molar distalization and tooth movement. Objectives of the study: 1) identify factors contributing to molar distalization and tooth movement; 2) analyze the effectiveness of Invisalign technology in molar distalization and tooth movement. Methods: The study was conducted in 2020-2022 in Baoding (PRC) based on Baoding's first central hospital. Forty patients (mean age 28.5 ± 1.5 years, 18-35 years; 20 women and 20 men) participated in the study. Results: All patients had mild to moderate degrees of tooth crowding, with an angle class II malocclusion, as well as maxillary third molars. Before and after the therapy, the condition of the alveolar bone, soft tissues, and facial height were measured. Fixation of the anterior teeth was performed. Calculations of the distal molar movement were performed. For orthodontic procedures, the second M of the upper jaw were moved, and then the first molars were moved. Discussion: Distalization of the upper molars was found to be an effective movement, with an efficiency of about 83% when vertical rectangular attachments were used. The first molar was moved distally by 2.85 mm without significant tilt or movement in the vertical plane.

Three-dimensional finite element study of mandibular first molar distalization with clear aligner

OBJECTIVES

This study aimed to construct the finite element model of the mandibular first molar with the invisible appliance and explore the dentition movement characteristics of the mandibular first molar when using micro-implant anchorage and different initial positions of the first molar.

METHODS

Models of the mandible, tooth, periodontal membrane, and invisible appliance were constructed using cone beam computed tomography (CBCT) data. The two groups were divided into the non-anchorage group and the micro-implant group (between the roots of the first molar and the second molar) based on whether the elastic traction of the micro-implant was assisted or not. The two groups were divided into the following conditions based on the starting position of the first molar: Working condition 1: the distance between the first molar and the second premolar was 0 mm; working condition 2: the distance between the first molar and the second premolar was 1 mm; working condition 3: the distance between the first molar and the second premolar was 2 mm; working condition 4: the distance between the first molar and the second premolar was 3 mm. The data characte-ristics of total displacement and displacement in each direction of dentition were analyzed.

RESULTS

In the non-ancho-rage group, all the other teeth showed reverse movement except for the first molar which was moved distally. Meanwhile, in the micro-implant group, except for a small amount of mesial movement of the second molar in wor-king condition 1, the whole dentition in other working conditions presented distal movement and anterior teeth showed lingual movement, among which the distal displacement of the first molar in working condition 4 was the largest. With the change of the initial position of the first molar to the distal, the movement of the first molar to the distal, the premolar to the mesial, and the anterior to the lip increased, while the movement of the second molar to the mesial decreased.

CONCLUSIONS

The micro-implant can effectively protect the anterior anchorage, increase the expression rate of molar distancing, and avoid the round-trip movement of the second molar. The initial position of the first molar movement is related to the amount of distancing and the remaining tooth movement.

Association of Mandibular Posterior Anatomic Limit with Skeletal Patterns and Root Morphology Using Three-Dimensional Cone Beam Computed Tomography Comprehensive Analysis

This study aimed to clarify the relationship between the mandibular posterior anatomic limit (MPAL) and skeletal anteroposterior and vertical skeletal patterns, with consideration of factors that may be related. In total, 230 people were included: 49 Japanese, 122 Egyptian, and 59 Korean people. The MPAL was measured at 0, 2, 4, and 6 mm from the root furcation along the sagittal and cuspal lines at the distance from the distal root of the mandibular right second molar to the mandibular cortex of the lingual bone. Eight different MPALs were evaluated using multiple regression analysis with explanatory variables for anteroposterior and vertical skeletal patterns and qualitative variables for age, sex, population, the presence of third molars, number of roots, presence of C-shaped roots, and Angle malocclusion classification. The MPAL was significantly larger as the mandibular plane angle decreased. The MPAL near the root apex was significantly larger as the A-nasion-point B angle increased, and the MPAL near the root apex measured at the cuspal line was significantly larger for C-type roots. The present study showed that a C-shaped root affected the MPAL in addition to the anteroposterior and vertical skeletal patterns.

En-Mass Retraction of Maxillary Anterior Teeth with Severe Proclination and Root Resorption-A Case Report

Molar distalization has been a validated method to correct dental sagittal relationships and create space to relieve mild to moderate crowding. In the current case report, an adult female patient had a mild skeletal Class III relationship and dental Class III molar relationship. Four premolars and one lower incisor were extracted during the previous two rounds of orthodontic treatments, and the maxillary anterior teeth were left with severe proclination and root resorption. Limited by the available teeth, extraction was not an option for her. Thus, molar distalization with TADs was the best option used in the treatment to address her chief complaint. In addition, a proper bite opening was performed to eliminate occlusion trauma. Utilizing the mid-palatal TADs, the maxillary central incisors were retracted 7.9 mm and retroclined 33 degrees, and the molar distalization was achieved as much as 8 mm. The cross-section slices of CBCT images confirmed the proper retraction of maxillary incisors and well-positioned roots in the alveolar bone. Moreover, the root resorption was not worsened from the treatment. Clinically, the maxillary anterior teeth were preserved esthetically and functionally. This case report illustrates that with proper diagnosis and treatment mechanics, significant tooth movement can be achieved even on extremely proclined maxillary incisors with severe root resorption.

Nonextraction Correction of Class II Malocclusion by Pendulum Appliance

A 13-year-old female patient, presented with the chief complaint of forwardly placed upper front teeth. On examination and analysis of relevant records, she was diagnosed as an Angle's Class II malocclusion on a skeletal Class I base. It was decided to treat the patient with a nonextraction treatment approach with the help of maxillary molar distalization followed by fixed mechanotherapy.

Efficacy of mandibular molar distalization by clear aligner treatment

OBJECTIVES

At present, the research on clear aligner of molar distalization mainly focuses on the upper jaw, while the research on mandibular molars is few.This study aims to evaluate the therapeutic effect of mandibular molars distalization with clear aligner via cone beam CT (CBCT) and Dolphin software.

METHODS

Twenty cases of mandibular molars with clear aligner were included according to the inclusion and exclusion criteria. CBCT was taken before treatment (T0) and when the first molar was moved in place (T1). Dolphin software was used to measure the effectiveness of molar distalization. Three-dimensional changes in direction and the impact on the incisors and facial soft and hard tissues were evaluated.

RESULTS

The effective rates of crown and root distalization of the second and first mandibular molars were 74%, 49%, and 71%, 47%, respectively. The second and first molars were both the distal buccal cusp with the largest distalization [(2.15 ± 0.91) mm and (1.85±1.09) mm], respectively, with significant difference between the T0 and T1 (P<0.05). The second and first molars were accompanied by depression, distal tilt, and buccal tilt with 1.06 mm, 2.10°, 2.27°, and 0.91 mm, 1.62°, and 1.91°, respectively, with significant differences between the T0 and T1 (all P<0.05). There was no obvious difference between men and women. The mandibular central incisor showed a lip-side movement of 1.02 mm, a depression of 0.82 mm, a mesial incline of 0.66°, and a crown-lip torque of 1.51° after molar distalization, with significant differences between the T0 and T1 (all P<0.001). Only the lower lip thickness increased by 0.1 cm, the length of the lower lip increased by 0.1 cm, and the ANS-ME (distance from anterior nasal spine to submental point) decreased by 0.13 cm, with significant differences between the T0 and T1 (all P<0.05).

CONCLUSIONS

Clear aligner can effectively move mandibular molars farther, the crown is more effective than the root, and it is tilted. The second mandibular molar is more effective than the first mandibular molar in its distant displacement and three-dimensional changes. Molar distalization causes minor changes in mandibular incisors and facial soft and hard tissues.

Factors associated with the maxillary third molar position after total arch distalization using a modified C-palatal plate in adolescents

INTRODUCTION

The purpose of this study was to evaluate the long-term position of erupted third molars after maxillary total arch distalization using modified C-palatal plates (MCPPs) in adolescents and to identify factors associated with these positions.

SETTING AND SAMPLE POPULATION

Sixty-two third molars (male: 20, female: 42) in Class II patients treated with MCPPs and thirty-nine teeth for the Control group (male: 22, female: 17).

MATERIALS AND METHODS

Samples were analyzed using panoramic radiographs taken initially (T0), after treatment (T1) and after >3 years retention (T2). Third molars were classified as downward (Group A, N = 31; males: 12, females: 19) and upward (Group B, N = 31; males: 8, females: 23) based on their vertical position after treatment. Analysis of variance and multiple logistic regression analysis were performed.

RESULTS

The vertical position of the third molars of Group A, Group B, and the Control showed a 2.2, 3.5 and 2.7 mm downward movement at T2. However, there was no difference in the amount of third molar eruption among the groups. Regarding factors affecting the vertical distance of the third molar, Age, C8-OP, ∠8-OP and D7-T at the initial affected vertical position of the third molars after molar distalization (P < .05).

CONCLUSIONS

Group A and B showed no difference in the third molar eruption during retention after total arch distalization. This study suggests that it might be unnecessary to extract the developing third molar before molar distalization in Class II adolescents.

Occlusal Plane Changes After Molar Distalization With a Pendulum Appliance in Growing Patients with Class II Malocclusion: A Retrospective Cephalometric Study

Objective

This study aimed to evaluate the skeletal and dental changes after distalization with a pendulum appliance in growing patients with Class II malocclusion, focusing on the occlusal plane (OP).

Methods

The sample included 24 patients with Class II malocclusion (10 boys, 14 girls); their mean age was 12.1 years. All patients underwent molar distalization and had 2 serial cephalograms traced at baseline (T1) and after distalization (T2). Angular and linear dental changes were calculated by taking the sella-nasion (SN), palatal plane (PP), and pterygoid vertical as reference. OP inclination was compared with SN, PP, and mandibular plane. The collected data were computed for all the tested variables, and one-way paired t-test was used to assess the significance of the differences between the time points. α was set at 0.05. Multiple linear regressions were used to predict the OP changes.

Results

The mean total treatment time was 8±2 months to obtain a super Class I molar relationship. In T1-T2 interval, statistically significant incisor buccal tipping of 5°±3.6° (p<0.05), first molar distal tipping of 8.9°±8.3° (p<0.001), and second molar tipping of 8.2°±8.1° (p<0.001) were observed. The maxillary first and second molars moved significantly backward by 2.8±3.2 mm (p<0.05) and 3.7±2.7 mm (p<0.001), respectively. Only the premolars showed a statistically significant anchorage loss of 2.7±3.3 mm (p<0.05); overjet increased significantly at 1.3±1.2 mm (p<0.05). Regarding the OP, none of the tested variables showed any statistically significant changes between T1-T2.

Conclusion

The pendulum appliance showed efficacy in distalizing the maxillary first and second molars at the expense of anterior anchorage loss. The OP did not show statistically significant changes after molar distalization.

Consecutive use of mini-implants in the palate to treat skeletal maxillary constriction and Class II malocclusion in an adult case

This report describes the successful use of two multifunctional mini-implants that were inserted into the palate in the treatment of an 18-year-old woman in whom the maxilla was skeletally narrowed and the molars have migrated mesially on both sides. Three different appliances were used in sequence in the course of treatment: first, an appliance supported by bone and teeth (hybrid hyrax) for surgically-assisted rapid maxillary expansion (SARME); second, a distalization device supported by mini-implants to achieve molar distalization; and third, a transpalatal arch (TPA) stabilized by mini-implants to allow indirect anchorage during retraction of the incisors. The mini-implants in the palate led to a reduction in the adverse effects of the SARME procedure and made treatment with cervical headgear unnecessary. TPA stabilized by the mini-implant was also used to retract the anterior teeth en masse, with no need for alterations in the treatment mechanism and using routine orthodontic methods.

Efficient Distalization of Maxillary Molars with Temporary Anchorage Devices for the Treatment of Class II Malocclusion

Treatment of Class II malocclusion often requires maxillary molar distalization. However, when applying distalization forces on the maxillary molars, anchorage loss may occur in different degrees not only during molar distalization (such as distal tipping of maxillary molars and mesial movement and proclination of the anterior teeth) but also during the subsequent stage of anterior teeth retraction (such as mesial movement of maxillary molars). All these movements are considered as unwanted side effects, which diminish the clinical effectiveness of distalization. Miniscrew implants can be used as temporary anchorage devices (TADs) to enhance anchorage and, if properly used, to counterbalance the side effects. Among the different available systems, the TAD-supported amda® can be considered as a simple, noncompliant, minimally invasive, and very efficient approach that can be used for the comprehensive treatment of patients with Class II malocclusion not only to distalize the maxillary molars bodily without or with minimal distal tipping and without proclination of the anterior teeth but also in combination with full-fixed appliances to retract and intrude the anterior teeth.

Full-step Class II Correction Using a Modified C-palatal Plate for Total Arch Distalization in an Adolescent

A 13-year-old adolescent male patient had a convex profile, severe overjet, and deep overbite with a skeletal Class II pattern. His maxillary dentition was distalized using a modified C-palatal plate (MCPP), and the treatment outcome was stable. After 37 months of total treatment, a pleasing profile and a favorable Class I occlusion was successfully achieved with 5 mm of distalization in the maxillary dentition. MCPP is a viable treatment option for full-step Class II in adolescents, especially when the patients/parents decline the extraction option.

Treatment of class II malocclusion and unerupted upper canines with self-ligating appliance

Treatments without tooth extractions have become more popular over the last two decades. In this context, expansion of the maxillary arch is an interesting treatment option for cases in which space is required and other factors not favoring extractions (such as the facial profile) are present. According to several authors, this posterior expansion can be obtained using a system comprising self-ligating brackets and superelastic nickel-titanium arches. The present article aims to report a case of a young patient with Class II, Division 2 malocclusion, with impacted upper canines and significant arch length-tooth discrepancy.

METHODS

The case was treated by means of a passive self-ligating appliance in association with Class II elastics and coil spring for distalizing the molars. This treatment alternative was effective for correcting Class II and obtaining space to correct tooth positioning.

Pendulum and modified pendulum appliances for maxillary molar distalization in Class II malocclusion - a systematic review

OBJECTIVE

The main purpose of the present systematic review was to evaluate the quantitative effects of the pendulum appliance and modified pendulum appliances for maxillary molar distalization in Class II malocclusion.

MATERIALS AND METHODS

Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus and key journals and review articles; the date of the last search was 30 January 2017. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP).

RESULTS

In total, 203 studies were identified for screening, and 25 studies were eligible. The quality assessment rated four (16%) of the study as being of strong quality and 21 (84%) of these studies as being of moderate quality. The pendulum appliances showed mean molar distalization of 2-6.4 mm, distal tipping of molars from 6.67° to 14.50° and anchorage loss with mean premolar and incisor mesial movement of 1.63-3.6 mm and 0.9-6.5 mm, respectively. The bone anchored pendulum appliances (BAPAs) showed mean molar distalization of 4.8-6.4 mm, distal tipping of molars from 9° to 11.3° and mean premolar distalization of 2.7-5.4 mm.

CONCLUSIONS

Pendulum and modified pendulum appliances are effective in molar distalization. Pendulum appliance with K-loop modification, implant supported pendulum appliance and BAPA significantly reduced anchorage loss of the anterior teeth and distal tipping of the molar teeth.

Maxillary molar distalization therapy in adult patients: a multicentre study

OBJECTIVES

To evaluate dento-skeletal changes following conventional anchorage molar distalization therapy in adult patients.

SETTING AND SAMPLE POPULATION

Thirty-three patients (25 women, mean age 23 years 1 months ± 3 months; 8 men, mean age 28 years 3 months ± 7 months) were recruited from 4 Board Certified specialists. All subjects underwent molar distalization therapy using intra-oral distalizing appliances.

SUBJECTS AND METHODS

Cephalometric headfilms were available for all subjects before (T1) and at the end of comprehensive treatment (T2). The initial and final measurements and treatment changes were compared by means of a paired t-test.

RESULTS

Mean total treatment time was 3 years 2 months ± 6 months. Maxillary first molar distalized 2.9 ± 0.6 mm contributing 64.4% to Class II molar correction, whereas mandibular first molar showed a concomitant mesial movement of 1.6 ± 0.5 mm. Maxillary incisors retroclined an average of 5.8° ± 3.9°, lower incisors proclined 4.1° ± 1.1° and the occlusal plane rotated downwards and backwards 1.8° ± 2.1°. Clockwise rotation of the mandible (1.7° ± 0.5°) and increase in lower facial height (2.5 ± 1.5 mm) were also observed.

CONCLUSIONS

Maxillary molar distalization therapy can be successfully performed in adult patients despite a slight increase in vertical facial dimension should be considered.

An active, skeletally anchored transpalatal appliance for derotation, distalization and vertical control of maxillary first molars

OBJECTIVE

The objective of this investigation was to evaluate treatment outcomes of the skeletally anchored 'Frog' appliance.

DESIGN

A single-centre, retrospective study was performed.

SETTING

Private orthodontic practice.

PARTICIPANTS

Patients who had undergone comprehensive orthodontic treatment with the skeletally anchored 'Frog' appliance.

METHODS

43 participants (20 males and 23 females) who had received treatment with the skeletally anchored 'Frog' appliance where included. In order to explore dentoalveolar and skeletal treatment outcomes, pre- (T1) and post- (T2) treatment measurements were performed on patients' plaster models and cephalometric images. Comparisons between T1 and T2 were made by means of a Student's t-test. All statistical analyses were conducted at the 0·05 level of statistical significance.

RESULTS

Study model analysis revealed a statistically significant derotation of maxillary molars (μΔT2-T1=9·5°, P<0·001) as well as an increase in transverse arch dimensions at the end of treatment (μΔT2-T1=2·2 mm, P<0·001). Cephalometric changes included bodily distalization of maxillary molars (μΔ(T2-T1)=-1·9 mm, P<0·001), as well as noticeable angular displacement (μΔT2-T1=4·1°, P=0·004). No significant anchorage loss was observed, as displayed by the limited change in maxillary incisor position (μΔ(T1-T2)=0·2 mm, P=0·45). In addition, excellent vertical control of the maxillary molars was achieved, with no change in the mandibular plane (ML/NSL) angle (μΔT2-T1=0·3°, P=0·38).

CONCLUSIONS

The skeletal 'Frog' is effective in derotating and distalizing maxillary molars without anchorage loss and with excellent vertical control.

Maxillary molar distalization with MGBM-system in class II malocclusion

AIMS

Objective of this retrospective study was to evaluate the treatment effects of the MGBM-System (G.B Maino, A. Giannelly, R. Bernard, P. Mura), a new intraoral device to treat Class II malocclusions.

MATERIALS AND METHODS

A retrospective study was conducted to compare the pre-distalization and post-distalization cephalograms and dental model casts of 30 patients (15 male, 15 female) with Class II malocclusion treated with MGBM-System. Mean age at the beginning of treatment was 13.3 years (standard deviation 3.3). Angular, horizontal and vertical measurements were recorded to monitor skeletal and dental-alveolar changes. Molar movements in horizontal plane were monitored by making dental measurements on dental model casts.

RESULTS

The MGBM-System produced a rapid molar distalization and Class II relationship was corrected in 8 months ± 2.05, on average. The maxillary first molars were distalized of 4.14 (PTV-6 cemento-enamel junction), associated with a significant distal axis incline of 10. 5° referred to SN and a significant intrusion of 1.3 mm (PP). As for anchorage loss, the first premolar exhibited a significant mesial movement of 0.86 mm, associated with a significant mesial axis incline of 2.46°. No significative changes in either sagittal or vertical skeletal relationship were observed.

CONCLUSION

The results suggest that the MGBM-System is an efficient and reliable device for distalizing the maxillary permanent first and second molars.