Soft tissue, skeletal and dentoalveolar changes following conventional anchorage molar distalization therapy in class II Non-growing subjects: a multicentric retrospective study

Effectiveness of Clear Aligners on Sequential Maxillary Molar Distalization: Discrepancy between Treatment Goal and Outcome

Objectives: The purpose of this preliminary study was to determine the differences between planned and actual maxillary molar movements after the completion of treatment with an initial set of clear aligners including sequential maxillary molar distalization. Methods: The data records of 14 non-growing patients who completed orthodontic treatment with sequential maxillary molar distalization using clear aligners were retrospectively evaluated (n= 14, 4 males and 10 females, 33.61 ± 8.57 years). Data on planned tooth movements were obtained from ClinCheck software (ClinCheck Pro version 5.3). The amounts of actual tooth movements were obtained by performing superimposition of lateral cephalograms taken before and after treatment. The amounts of distal translation and tipping between planned and actual maxillary molar movements were compared with the paired Student's t-test. Results: The statistically significant differences between planned and actual translation movements of maxillary first and second molars were shown after completing treatment with the first series of aligners (p < 0.05). The average actual amount of molar distalization on maxillary first molars was less than the planned amount by 1.32 ± 0.42 mm. Similarly, the average actual amount of molar distalization on maxillary second molars was less than the planned amount by 1.57 ± 0.45 mm. The accuracy for molar distalization, namely, the percentage of actual distal translation to planned movement, was 40.11% for maxillary first molars and 35.39% for maxillary second molars. However, the difference between the planned and actual angulation movements was not significant (p > 0.05). Conslusions: In conclusion, the amounts of actual distal translation of maxillary molars through the utilization of clear aligners were significantly lower than planned. However, there were no statistically significant differences between the degrees of actual and planned molar angulation movement.

Molar Distalization by Clear Aligners with Sequential Distalization Protocol: A Systematic Review and Meta-Analysis

INTRODUCTION

With the popularity of clear aligners, the sequential distalization protocol has been more commonly used for molar distalization. However, the amount of molar distalization that can be achieved, as well as the accompanying side effects on the sagittal dimension, are unclear.

METHODS

Registered with PROSPERO (CRD42023447211), relevant original studies were screened from seven databases (MEDLINE [PubMed], EBSCOhost, Web of Science, Elsevier [SCOPUS], Cochrane, LILACS [Latin American and Caribbean Health Sciences Literature], and Google Scholar) supplemented by a manual search of the references of the full-reading manuscripts by two investigators independently. A risk of bias assessment was conducted, relevant data were extracted, and meta-analysis was performed using RStudio.

RESULTS

After the screening, 13 articles (11 involving maxillary distalization, two involving mandibular distalization) met the inclusion criteria. All studies had a high or medium risk of bias. The meta-analysis revealed that the maxillary first molar (U6) mesiobuccal cusp was distalized 2.07 mm [1.38 mm, 2.77 mm] based on the post-distalization dental model superimposition, and the U6 crown was distalized 2.00 mm [0.77 mm, 3.24 mm] based on the post-treatment lateral cephalometric evaluation. However, the U6 mesiobuccal root showed less distalization of 1.13 mm [-1.34 mm, 3.60 mm], indicating crown distal tipping, which was validated by meta-analysis (U6-PP angle: 2.19° [1.06°, 3.33°]). In addition, intra-arch anchorage loss was observed at the post-distalization time point (U1 protrusion: 0.39 mm [0.27 mm, 0.51 mm]), which was corrected at the post-treatment time point (incisal edge-PTV distance: -1.50 mm [-2.61 mm, -0.39 mm]).

CONCLUSION

About 2 mm maxillary molar distalization can be achieved with the sequential distalization protocol, accompanied by slight molar crown distal tipping. Additional studies on this topic are needed due to the high risk of bias in currently available studies.

The effect of third molars on maxillary molar distalisation using a miniscrew-supported 3D® maxillary bimetric distalising arch

Objectives: The aim of the present study was to investigate the effect of third molars on the efficiency and biomechanics of a novel miniscrew-supported 3D® Maxillary Bimetric Distalising Arch (3D-MBDA).

Methods: Twenty-three patients, whose third molars were either extracted at the beginning of treatment (Group 1, n =11) or retained (Group 2, n =12), were included in the study. Lateral cephalometric films and dental casts, taken at the beginning (T0) and at the end of upper molar distalisation (T1), were analysed to study the differences between groups.

Results: Crown distalisation of the first molars was similar between the groups; however, root distalisation, both at the trifurcation and apex levels, intrusion at the mesiobuccal cusp tip, and the distalisation rate were significantly higher in Group 1. The resultant tipping of the first molars in both groups was mesially-directed, unlike the usual distal tipping. The second molars distalised more, displaced less vestibularly and rotated mesiobuccally in Group 1, whereas they demonstrated a significantly higher vestibular displacement and distobuccal rotation in Group 2. The mean distalisation time was significantly shorter in Group 1 when compared to Group 2. The miniscrew success rate was 95.5% for Group 1 and 91.7% for Group 2.

Conclusion: The miniscrew-supported 3D-MBDA was found to have greater effects on root distalisation and the final inclination of the molars. The third molars were associated with limited root movement, unfavourable displacement of the second molars, as well as a slower distalisation rate. Therefore, the extraction of third molars prior to distalisation is recommended, especially when the miniscrew-supported 3D-MBDA is the appliance choice.

Nonsurgical treatment of an adult with a skeletal Class II gummy smile using zygomatic temporary anchorage devices and improved superelastic nickel-titanium alloy wires

Patients with a severe gummy smile and a skeletal Class II profile are difficult to treat. This case report describes an effective treatment alternative for improving a gummy smile in a patient with a severe Class II molar relationship, severe crowding, and lip protrusion using zygomatic anchorage devices and improved superelastic nickel-titanium wires. A 36-year-old woman had an excessive overjet and a deep overbite with a bilateral Angle Class II molar relationship. The cephalometric analysis demonstrated a Class II skeletal relationship (ANB, 9.5°), retroclination of the mandible (FMA, 38.4°), and severe labial inclination of the mandibular incisors (IMPA, 101.9°). The main treatment objectives included normalizing the overjet and overbite, improving the gummy smile, and establishing a satisfactory occlusion. During treatment with fixed appliances, intrusion of the total maxillary dentition using skeletal anchorage and elimination of the bimaxillary protrusion were achieved. Improvement of the lateral profile and gummy smile enhanced facial esthetics. Intrusion and distalization of the maxillary dentition with skeletal anchorage and improved superelastic nickel-titanium wires provided a satisfactory dental occlusion, esthetic improvement, and adequate function. This approach should be considered as an alternative treatment option to orthognathic surgery for adults with high-angle skeletal Class II malocclusion and a gummy smile.

Asymmetric Expansion with a Modified Quad Helix for Treatment of Isolated Crossbite

Unilateral posterior crossbite often involves only one tooth, especially upper first molar; in these cases it is never easy to obtain an asymmetrical movement of a molar and a proper planning of the orthodontic device with its anchorage is necessary to avoid arch overexpansion. Thanks to its simplicity and efficacy, the modified Quad Helix here described represents a valid therapeutic tool in cases of isolated posterior crossbite.

Comparison between direct vs indirect anchorage in two miniscrew-supported distalizing devices

OBJECTIVE

To compare two distalizing devices supported by palatal miniscrews, the MGBM System (MGBM) and the Distal Screw appliance (DS), in dental Class II patients.

MATERIALS AND METHODS

Pretreatment (T1) and postdistalization (T2) lateral cephalograms of 53 Class II malocclusion subjects were examined. MGBM consisted of 29 patients (16 males, 13 females) with a mean pretreatment age of 12.3 ± 1.5 years; DS consisted of 24 patients (11 males, 13 females) with a mean pretreatment age of 11.3 ± 1.2 years. The mean distalization time was 6 ± 2 months for MGBM and 9 ± 2 months for DS. Initial and final measurements and treatment changes were compared by means of a Student's t-test.

RESULTS

Maxillary superimpositions showed that the maxillary first molar distalized an average of 5.5 mm in the MGBM and 3.2 mm in the DS between T1 and T2; distal molar tipping was greater in the MGBM (10.3°) than in the DS (3.0°). First premolar showed a mean mesial movement of 1.4 mm, with a mesial tipping of 4.4° in the MGBM; on the contrary, first premolar showed a distal movement of 2.2 mm, with a distal tipping of 6.2°, in the DS.

CONCLUSIONS

The MGBM system resulted in greater distal molar movement and less treatment time, resulting in more efficient movement than was associated with the DS; DS showed less molar tipping during distalization.

Maxillary molar distalization with aligners in adult patients: a multicenter retrospective study

Background

The aim of the present study was to test the hypothesis that bodily maxillary molar distalization was not achievable in aligner orthodontics.

Methods

Forty lateral cephalograms obtained from 20 non-growing subjects (9 male, 11 female; average age 29.73 years) (group S), who underwent bilateral distalization of their maxillary dentition with Invisalign aligners (Align Technology, Inc., San José, CA, USA), were considered for the study. Skeletal class I or class II malocclusion and a bilateral end-to-end class II molar relationship were the main inclusion criteria. Cephalograms were taken at two time points: (T0) pretreatment and (T2) post-treatment. Treatment changes were evaluated between the time points using 39 variables by means of paired t test. The level of significance was set at P < 0.05.

Reproducibility of measurements was assessed by the intraclass correlation coefficient (ICC).

Results

The mean treatment time was 24.3 ± 4.2 months. At the post-treatment point, the first molar moved distally 2.25 mm without significant tipping (P = 0.27) and vertical movements (P = 0.43). The second molar distalization was 2.52 mm without significant tipping (P = 0.056) and vertical movements (P = 0.25). No significant movements were detected on the lower arch. SN^GoGn and SPP^GoGn angles showed no significant differences between pre- and post-treatment cephalograms (P = 0.22 and P = 0.85, respectively).

Conclusions

Aligner therapy in association with composite attachments and class II elastics can distalize maxillary first molars by 2.25 mm without significant tipping and vertical movements of the crown. No changes to the facial height were revealed.

A Noble, Easy and Conceptual Radiographic Analysis to Assess the Type of Tooth Movement (Molar Distalization)

CONTEXT AND AIM

Bodily tooth movement is desirable in the field of Orthodontics and so is with molar distalization. Till date there is no such analysis available which could gauge and quantify the molar distalization and the type of tooth movement achieved, therefore one was required.

MATERIALS AND METHODS

An OPG and Lateral cephalogram was used taking Inter orbitale plane and FH plane respectively as reference lines and the analysis was devised to measure the amount and type of tooth movement achieved in distalization of molar.

CONCLUSION

This analysis is a noble, easy and conceptual analysis to assess the type of tooth movement achieved during molar distalization and other molar movements using Lateral cephalogram and orthopantomogram.

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.

Comparative evaluation of molar distalization therapy with erupted second molar: Segmented versus Quad Pendulum appliance

Background

There are controversial opinions about the effect of erupted second molars on distalization of the first molars. Most of the distalizing devices are anchored on the first molars, without including second molars; so, differences between sequentially distalize maxillary molars (second molar followed by the first molar) or distalize second and first molars together are not clear. The aim of the study was to compare sequential versus simultaneous molar distalization therapy with erupted second molar using two different modified Pendulum appliances followed by fixed appliances.

Methods

The treatment sample consisted of 35 class II malocclusion subjects, divided in two groups: group 1 consisted of 24 patients (13 males and 11 females) with a mean pre-treatment age of 12.9 years, treated with the Segmented Pendulum (SP) and fixed appliances; group 2 consisted of 11 patients (6 males and 5 females) with a mean pre-treatment age of 13.2 years, treated with the Quad Pendulum (QP) and fixed appliances. Lateral cephalograms were obtained before treatment (T1), at the end of distalization (T2), and at the end of orthodontic fixed appliance therapy (T3). A Student t test was used to identify significant between-group differences between T1 to T2, T2 to T3, and T1 to T3.

Results

QP and SP were equally effective in distalizing maxillary molars (3.5 and 4 mm, respectively) between T1 and T2; however, the maxillary first molar showed less distal tipping (4.6° vs. 9.6°) and more extrusion (1.1 vs. 0.2 mm) in the QP group than in the SP group, as well as the vertical facial dimension, which increased more in the QP group (1.2°) than in the SP group (0.7°). At T3, the QP group maintained greater increase in lower anterior facial height and molar extrusion and decrease in overbite than the SP group.

Conclusion

Quad Pendulum seems to have greater increase in vertical dimension and molar extrusion than the Segmented Pendulum.

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.

Class I malocclusion with severe double protrusion treated with first premolars extraction

Angle Class I malocclusion with bymaxillary protrusion is characterized by severe buccal tipping of incisors, which causes upper and lower lip protrusion. First premolars extraction is recommended to reduce facial convexity as a result of anterior teeth retraction, which keeps canines and first molars in key to occlusion. In order to yield orthodontic results that are compatible with ideal esthetic and cephalometric outcomes, the space closure phase needs to be carried out with overbite and incisors torque control. The majority of cases also requires maximum anchorage of posterior teeth. This case was presented to the Brazilian Board of Orthodontics and Facial Orthopedics (BBO) as a requirement for the title of certified by the BBO.

Treatment efficiency of mini-implant-borne distalization depending on age and second-molar eruption

OBJECTIVE

The aim of this study was to evaluate the efficiency of molar distalization depending on age and second-molar eruption using the Beneslider.

MATERIALS AND METHODS

Treatment of 51 patients (mean age 17.8 ± 9.6 years) was investigated retrospectively by means of pre- and posttreatment cephalograms. Patients were divided into three groups: 14 children with unerupted upper second molars (group 1), 23 adolescents with second molar in place (group 2), and 14 adults (group 3). The distalization forces applied were 2.4 N in group 1 and 5.0 N in groups 2 and 3. Treatment changes were evaluated and examined statistically for significant differences.

RESULTS

In all patients a Class I molar relationship was achieved. All mini-implants remained stable during treatment. Mean distalization distance as measured by the displacement of the center of resistance was 3.6 ± 1.9 mm (range 1.2-8.5 mm depending on treatment needs). Since no significant tipping was detected, the type of movement can be described as bodily movement. Mean overall distalization speed was 0.6 ± 0.4 mm per month. There were no statistical differences between the groups.

CONCLUSION

We found the Beneslider to be an effective appliance that enables bodily distalization in adequate treatment time. The higher resistance due to erupted second molars can be compensated by the use of higher forces without significantly reducing distalization speed.

Long-term evaluation of the molar movements following Pendulum and fixed appliances

OBJECTIVE

To describe the molar movements and skeletal changes associated with Pendulum-fixed appliance treatment and the long-term postretention period.

SUBJECTS AND METHODS

The treatment sample consisted of 76 Class II patients, 35 males and 41 females. Lateral cephalograms were obtained at the start of treatment (T1); the end of distalization (T2); the end of orthodontic fixed appliance therapy (T3); and long-term observation (7 years 2 months later; T4). Mean age was 12 years 11 months at T1, 13 years 8 months at T2, 15 years 4 months at T3, and 22 years 5 months at T4. The average amount of Class II molar relationship was 3.1 mm, with a mean overjet of 5.9 mm at the beginning of treatment. A paired t-test was used to identify significant between-group differences between T2-T4 and T3-T4.

RESULTS

Distal molar movement was obtained during the distalization phase (T2), and more than half of the distalizing effect was maintained at the end of maxillary growth (T4). Most of the relapse occurred during fixed appliance therapy (T3), whereas no significant change was detected in the postretention period (T4). The molar relationship did not show any significant difference between T2 and T4. The vertical facial dimension increased during the distalization phase (T2) and fixed appliance therapy (T3) but returned to the initial values during the postretention period (T4).

CONCLUSIONS

The Pendulum appliance induces significant dentoalveolar effects, which can be partially maintained during the long-term period. The Class I molar relationship does not change during completion of individual growth. Increase in vertical facial dimension represents a temporary effect.