Evaluation of an intraoral maxillary molar distalization technique

Effect of upper second molar eruption status on the efficiency of upper first molar distalization: a systematic review and meta-analysis

OBJECTIVES

To assess the distalization, tipping, and vertical movement of the maxillary first permanent molar in patients with and without erupted maxillary second molar (MSM).

METHODS

Eligibility criteria: Randomized/non-randomized clinical studies comparing distalization, tipping, and vertical movement of the maxillary first permanent molar in patients with and without erupted MSM. Information sources: Unrestricted literature search of six databases was conducted up to May, 2024. Risk of bias: The quality assessment of the studies was conducted using the Cochrane Risk of Bias Tool (ROBINS-I). Synthesis of results: Random effects meta- analyses using standardized mean differences (SMDs) and their 95% confidence intervals (CIs) were performed, followed by meta-regressions, sensitivity analyses, and assessment of the quality of evidence using GRADE.

RESULTS

Included studies: Eleven studies (8 retrospective and 3 prospective non-randomized trials) involving 562 participants (43.97% male) were included. Synthesis of results: Distalization was significantly more effective when the maxillary second molar was unerupted (9 studies; SMD = -0.41; 95% CI: -0.81--0.004; P = .04; I² = 68.6%). The eruption status of MSM has no significant effect on tipping (8 studies; SMD = -0.27; 95% CI: -0.68-0.15; P = .17), and vertical movement (4 studies; SMD = 0.08; 95% CI: -0.32-0.48; P = .57) of upper first molars during distalization. Sensitivity analyses showed no significant differences based on study design, appliance type, or anchorage type, confirming the robustness of the findings. The certainty in the estimates was very low due to high risk of bias, methodological weaknesses, and small sample sizes.

DISCUSSION

Limitations of evidence: The inclusion of non-randomized, mostly retrospective studies, unmatched baseline, Class II severity, and insufficient reporting of treatment duration are key limitations. Interpretation: Very low level of evidence indicates that it may be preferable to perform distalization before the eruption of the upper second molar.

REGISTRATION

PROSPERO (CRD42024591126).

Retrospective comparison of two different miniscrew-supported molar distalization methods applied in the buccal and palatal regions

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Effect of Second and Third Molar Eruption Stages on First Molar and Maxillary Arch Distalization With Modified Palatal Anchorage Plate and Beneslider: A 3D Finite Element Analysis

AIM

To analyze the effects of the maxillary second molar and third molar eruption stages on the distalization of first molars with a modified palatal anchorage plate (MPAP) and Beneslider using three-dimensional (3D) finite element analysis.

MATERIALS AND METHOD

Six finite element models (FEMs) of individual maxillary molar distalization and six FEM models of en-masse maxillary arch distalization (EMAD) at different stages of the maxillary molar eruption were created from cone-beam computed tomography (CBCT) images of the maxillary complex, and 3D displacements of the maxillary first and second molars were evaluated with MPAP and Beneslider.

RESULTS

On individual molar distalization, Beneslider showed first molar distal translation during the second and third molar follicular stages, while MPAP showed distal tipping of the first molar. With EMAD, either of the appliances showed distal tipping of the first molars. There was palatal rolling and extrusion of the first molars. The second molar showed buccal drifting with intrusion, and the incisors showed palatal displacement along with extrusion.

CONCLUSIONS

Second and third molar eruption stages had no adverse influence on first molar and en-masse maxillary arch distalization. Beneslider showed distal translation of the first molar, while distal tipping was seen with MPAP.

Biomechanical analysis of total arch maxillary distalization using infrazygomatic crest miniscrews: a finite element analysis study

AIM

To evaluate the maxillary incisors and canine's immediate movement tendency using three different power arms (PA) height levels during total arch maxillary distalization supported on infrazygomatic crest (IZC) miniscrews according to finite element analysis (FEA).

METHODS

Three finite element models of the maxilla were developed based on CBCT imaging of a teenage male patient presenting a Class II Division 1 malocclusion in the early permanent dentition. Maxillary complex, periodontium, orthodontic accessories, IZC miniscrews and an orthodontic wire were digitally created. The PAs were placed between canines and lateral incisors and projected at 4, 7, and 10 mm height distances. After that, distalization forces were simulated between PA and IZC miniscrews.

RESULTS

The anterior teeth deformation produced in the FEA models was assessed according to a Von Mises equivalent. The stress was measured, revealing tendencies of initial maxillary teeth movement. No differences were found between the right and left sides. However, there was a significant difference among models in the under-stress areas, especially the apical and cervical root areas of the maxillary anterior teeth. More significant extrusion and lingual tipping of incisors were observed with the 4 mm power arm compared to the 7 mm and 10 mm ones. The 10 mm power arm did not show any tendency for extrusion of maxillary central incisors but a tendency for buccal tipping and intrusion of lateral incisors.

CONCLUSION

The maxillary incisors and canines have different immediate movement tendencies according to the height of the anterior point of the en-masse distalization force application. Based on the PA height increase, a change from lingual to buccal tipping and less extrusion tendency was observed for the incisors, while the lingual tipping and extrusion trend for canines increased.

Evaluation of the effect of extraction in comparison to distalization on the maxillary third molars in class II malocclusion: a retrospective study

OBJECTIVE

To compare the effects of first premolar extraction versus distalization on the vertical position and mesiodistal angulation of maxillary third molars (MxM3) in adolescent class II patients.

METHODS

The panoramic x-rays (OPGs) of 200 adolescent class II patients with developing MxM3s were screened. The chosen sample consisted of 2 groups: Group 1 (Distalization) comprising 48 MxM3s, and Group 2 (Extraction) comprising 50 MxM3s. The pre- and post-treatment OPGs were traced to detect the mesiodistal angulation changes of the second molars (MxM2) and MxM3s.

RESULTS

The angulation and vertical position of the MxM3s at T0 & T1 were also evaluated using Archer's classification. The distalization group presented a non-significant decrease in the mean angulation of MxM2 and MxM3 (-2.4o & -4.5o uprighting respectively). In the extraction group, both MxM2 and MxM3 presented a highly significant decrease in the mean angulation (-10.5o & -11o uprighting respectively). The angulation and vertical position change of MxM3 significantly improved in the extraction group when compared to the distalization group (P < .001).

CONCLUSION

Significant uprighting and occlusal positioning of the maxillary third molars occurred in the premolar extraction treatment group when compared to the distalization treatment group. The results of the current study highlight the importance of recognizing maxillary third molars during orthodontic treatment planning of Class II malocclusion cases.

Vertical effects of distalization protocol with Clear aligners in Class II patients: a prospective study

BACKGROUND

The aim of the present prospective study was to detect the effects on vertical dentoskeletal dimension produced by molar distalization with Clear Aligners in a group of subjects with Class II malocclusion.

METHODS

The Clear Aligners Group (CAG) comprised 20 patients (13 females, seven males) with a mean age of 17.2±3.2 years. The same standardized protocol of sequential distalization was applied in all subjects. For each patient lateral cephalograms have been analyzed before treatment (T1) and at the end of the therapy (T2).

RESULTS

At the end of treatment, clear aligners were effective in the correction of Class II dental relationship with the correction of the overjet (-1.3 mm). The treated group showed statistically significant reduction in FMA angle (-1.3°) associated with a counterclockwise rotation of the occlusal plane (POccl^PF -3.1°; SN^POccl -4.2°) and a slight intrusion of maxillary first molars to palatal plane (-0.9 mm). Finally, statistically significant differences were detected in anterior facial height (N-Me) and in the ArGo^GoMe angle (-1.2 mm and -3.4°, respectively).

CONCLUSIONS

Upper molar distalization with clear aligners represents a valid alternative to non-extraction treatment of Class II malocclusion, reducing the extrusion of maxillary first molars and improving the control of the occlusal plane and of the vertical dimension.

Skeletal and dentoalveolar changes after total maxillary arch distalization using the casted palatal plate vs. buccal miniscrews: A randomized clinical trial

OBJECTIVES

To evaluate treatment changes after total maxillary arch distalization using the casted palatal plate compared with buccal miniscrews.

MATERIAL AND METHODS

This was a randomized, parallel, two-arm, single center trial. Participants were young adults with class II dental relationships and normal or horizontal growth patterns. The patients were treated with total distalization of the maxillary arch and were randomly allocated, according to the anchorage devices, between the plate group and the minivis group. The primary outcomes were sagittal, vertical and angular changes of molars and incisors, while the secondary outcomes were skeletal and soft tissue changes. Outcomes were evaluated on lateral cephalograms and blinding of outcome assessment was implemented. A multivariate analysis of Variance (MANOVA) tests were used and Bonferroni correction for multiple comparisons with P<0.001.

RESULTS

Forty patients (33 females and 7 males; mean age 20±3.1 years) where enrolled. A significant distalization of U6 was observed in both groups (4.33mm in the plate group and 1.88mm in the miniscrews group). It was combined with significant intrusion and non-significant distal tipping of the U6 in the plate group (1.85mm and 3.10°, respectively), while intrusion and distal tipping were non-significant in the miniscrew group (0.8mm and 2°, respectively). Both groups showed significant retraction and palatal inclination without vertical changes of U1. Only the plate group produced significant reduction of ANB and Wits. Upper and lower lips were retracted and the nasolabial angle increased significantly in both groups. There was no significant main effect of the appliance type on the comparison of treatment effects between the two groups (P=0.623). However, univariate comparisons showed that the plaque group showed greater distalization of the U6 (P<0.001).

CONCLUSIONS

Both the casted palatal plate and buccal miniscrews can be viable devices for total distalization of the maxillary arch in the treatment of class II patients. The casted plate may be considered when more extensive distalization is required.

Non-extraction Orthodontic Treatment Protocol of Moderate Crowding

Dental crowding is referred to as the swarming of teeth, mainly due to the discrepancy between the size of the jaw bases and that of the teeth. When the amount of space required for the teeth is more than that in the jaws, it leads to crowding. The prevalence of crowding has now increased to almost 30-60%. It can be classified into mild, moderate, and severe according to the amount of overlap. Depending on the severity of the crowding, the decision of extraction is made. The given case presents a non-extraction protocol for treating moderate crowding. The present case report explains the non-extraction treatment of moderate crowding using inter-proximal stripping.

Cephalometric and model evaluations after molar distalization using modified C-palatal plates in patients with severe arch length discrepancy

INTRODUCTION

This study aimed to evaluate the dentoskeletal and soft-tissue changes after molar distalization using modified C-palatal plates in patients with severe maxillomandibular arch length discrepancies.

METHODS

Twenty-four patients with Class I and II malocclusion (19.0 ± 7.3 years; 17 females and 8 males), who had severe maxillary crowding of >10 mm, and moderate mandibular crowding of >6 mm, underwent molar distalization using modified C-palatal plates and buccal miniscrews with approximately 300 g of force per side. Models were made, and cephalograms were taken before and after treatment. Cephalometric variables and arch dimensions were measured. Paired t test and Wilcoxon rank sum test were used for statistical analysis.

RESULTS

In the maxillary dentition, an average of 12.4 mm of crowding was resolved by molar distalization of 4.4 mm, interproximal stripping of 0.7 mm, and arch expansion. In the mandibular dentition, crowding of 6.7 mm was alleviated by molar distalization of 2.4 mm, an interproximal of 1.5 mm, and additional arch expansion. The incisor positions were maintained (SN-U1, 101.3°; IMPA, 88.8°), and soft-tissue profiles were improved (LL/E-line -1.1 mm; P < 0.001) after treatment.

CONCLUSIONS

Maxillary and mandibular tooth-size arch length discrepancy of 12.4 mm and 6.7 mm, respectively, were resolved by molar distalization, interproximal reduction, and arch expansion, whereas incisor positions were maintained, and soft-tissue profiles were improved. This could be a viable treatment option in patients with moderate-to-severe crowding.

A Three-Dimensional Finite Element Analysis of Mini-Implant supported K-Loop for Maxillary Molar Distalization

Introduction:

The study was conducted to assess the stress and displacement effects of a mini-implant supported k-loop on the maxillary dentition for distalization with 3-dimensional (3D) finite element stress analysis.

Materials and Methods:

A 3D model of the maxilla with all teeth, periodontal ligament, bone, mini-implants, brackets, and archwire was used in this study. The analytic model used in this study like brackets, wire, K-loop, and mini-implants was developed using a reverse engineering technique extracting the dimensional details of the physical parts using precision measuring instruments.

Results:

The distobuccal movement on the first molar and second molar were 0.26864 mm and 0.00833 mm, respectively. A total of 0.25 mm intrusion movement was seen on distal cusp of the first molar and 0.14 mm extrusion movement seen on mesial cusp of the first molar. A total of 0.25 mm and 0.00260 mm intrusion movement was seen on the distal cusp of the first molar and second molar, respectively. A total of 0.14 mm and 0.00324 mm extrusion movement was seen on the mesial cusp of the first molar and second molar, respectively.

Conclusions:

There was a large amount of distal displacement of the first molar, also negligible amount of tipping of the first molar and mesial movement of first premolar.

Stability of the Maxillary and Mandibular Total Arch Distalization Using Temporary Anchorage Devices (TADs) in Adults

Distalization with temporary anchorage devices (TADs) is commonly used to resolve crowding and to correct molar relationships in non-extraction cases. The purpose of this study was to quantify the treatment effects and post-treatment stability of total arch distalization with TADs in adults and thereby elucidate the clinical effect of this treatment modality. The subjects of the study were 39 adult orthodontic patients treated with total arch distalization with TADs. Lateral cephalograms and dental casts were taken at pretreatment (T0), post-treatment (T1), and the retention period (T2, 29.3 ± 12.8 months) to evaluate the vertical and horizontal movement of teeth, changes of arch width and molar rotation. It was concluded that even though there was a little relapse in the anteroposterior position of the maxillary and mandibular teeth during retention, there was no obvious relapse in the facial profile. Therefore, the total arch distalization can be used in patients with a moderate amount of arch length discrepancy effectively with stable retention.

Utilization of a 3D Printed Orthodontic Distalizer for Tooth-Borne Hybrid Treatment in Class II Unilateral Malocclusions

This paper introduces a novel method of 3D designing and 3D printing of a hybrid orthodontic tooth-borne personalized distalizer for treatment of unilateral Class II malocclusion. Research objectives were to clinically utilize 3D printed distalizers, appraise feasibility of this technique and compare two different biocompatible photopolymers (white and transparent). Frequency of distalizers’ debonding and patients’ aesthetical perception was evaluated on the set of 12 complete orthodontic treatments. The mean duration of treatment period with a bonded distalizer was 6.4 months. All cases were adults with unilateral Class II malocclusion managed with a hybrid approach as a part of Invisalign® comprehensive treatment. Results showed that such perspective practice is feasible for 3D design and in-office 3D printing of a personalized distalizer. Results also showed no clinically significant differences between both studied biopolymers. The paper discusses an evaluation of such personalized distalizer functionality with regard to the current state of the art and compares to conventional prefabricated alternatives like a Carriere® Distalizer™ appliance. Research showed a preference of patients towards transparent biocompatible photopolymer instead of the white A2 shade. The paper concludes that additive manufacturing from dental resins is a viable method in personalization and in-office 3D printing of orthodontic auxiliaries, particularly distalizers. New materials for orthodontic 3D printing endow enhanced individualization, thus more efficient treatment.

Digital Photoelastic Analysis of TAD-Supported Maxillary Arch Distalization

The objective of this study was to determine whether the distribution of compressional and tensional stress around tooth roots is influenced by the position of a temporary anchorage device and the length of the retraction hook during the distalization of the maxillary dentition. A photoelastic orthodontic model was made of photoelastic epoxy resin. Six combinations of three retraction hook lengths and two posterior Temporary skeletal anchorage devices (TAD) positions were established. Stress was applied through an elastic chain for each of the combinations. Digital photoelastic stress analysis measured the compression, tensional stress, and direction around the tooth root. Using this novel photoelastic model, we found that the distribution of compressional and tensional stress during the retraction of the maxillary dentition was significantly influenced by the position of the TAD and the length of the retraction hook.

Class II treatment of transverse maxillary deficiency with a single bone-borne appliance and hybrid clear aligner approach in an adult patient: A case report

This case report describes the successful orthodontic treatment of a 22-year-old female patient affected by Class II malocclusion, maxillary skeletal transverse deficiency, ectopic maxillary left lateral incisor, and mild mandibular crowding. Due to her adult skeletal age, a bone-borne appliance was applied in order to obtain both purely skeletal rapid maxillary expansion and bilateral molar distalization. After accurate matching between the pretreatment cone-beam computed tomography scan and digital models, 4 self-drilling miniscrews were inserted palatally using a computer-aided design and computer-aided manufacturing (CAD/CAM) surgical template to guide their correct and safe placement, and a bone-borne appliance was fitted. After this first phase, the hybrid clear aligner approach was used to obtain alignment, levelling, and arch coordination, with the use of a partial lingual fixed appliance on the maxillary incisors.

A Simple Technique Using a Modified Nance Appliance as Anchorage for Maxillary Molar Distalization—Two Case Reports

Maxillary molar distalization to correct a dental Class II molar relationship and to create space to relieve crowding has been a long-lasting subject of debate in orthodontics. Generally, to distalize maxillary molars, an intra-arch distalization appliance is favored over an inter-arch appliance since it does not utilize mandibular dentition as an anchorage, so some unwanted side effects on mandibular incisors can be avoided. A variety of intra-arch appliances have been developed to distalize maxillary molars, such as the pendulum, Jones jig, first class appliance, distal jet, and modified C-palatal plate. Although they could achieve efficient molar distalization, the learning curve of proper appliance insertion and activation is relatively long. In addition, the appliances are not comfortable for the patients due to the bulky activation units, especially when the activation units are designed in the palatal area. The current manuscript describes a novel and effective maxillary intra-arch molar distalization appliance—a modified Nance appliance technique, which consists of: (1) palatally, a big acrylic button against the palatal rugae and connected to the premolars with wide mesh pads; (2) buccally, regular brackets on maxillary premolars and first molars with sectional round stainless steel archwires and open coil springs between the second premolar and first molar. Either bilateral or unilateral maxillary molar distalization can be achieved with this appliance, and the Class II elastics are not needed. It is simple to be fabricated, delivered, and activated, and it is comfortable for patients.

Efficacy of clear aligners in producing molar distalization: Systematic review

Objectives:

The aim of this review is to systematically analyze the efficacy of molar distalization using clear aligners in non-growing Class II patients.

Materials and Methods:

A complete search across the electronic database through PubMed, Cochrane, Google scholar, LILACS, and manual search of orthodontic journals were done till 2019. Studies were selected on the basis of PRISMA guidelines.

Results:

A total of four articles were included in this review. The amount of molar distalization reported was 2–3 mm.

Conclusion:

Out of the four studies included. In all the studies a significant amount of distalization was reported. Three retrospective studies concluded that distalization with aligners is the most effective of all tooth movements. One study concluded that aligners effectively achieved distalization with an efficacy of 87%, other two studies concluded that aligners effectively distalized the molars with good control over vertical dimension and mesiodistal tipping.

Smart distalization of the upper arch with an easy, efficient and no-compliance procedure

In conventional Class II treatment, distalisation of the maxillary arch usually requires multiple phases of tooth movement during which anchorage loss can occur. In order to solve this issue, a rational and simple technique has been developed. Instead of using intraoral distalisers along with palatal mini-implants, Ni-Ti superelastic loops are used to obtain molar distalisation while buccal interradicular miniscrews (BIM), preferably placed between the roots of upper premolars, supply the necessary anchorage. Once the distalisation of molars and second premolars is performed, miniscrews are placed between the roots of first molars and second premolars after removing the previous miniscrews. Elastic chains or tie-backs, which go from the new miniscrews to the hooks of a 0.019×0.025-inch stainless-steel archwire, produce the retraction of incisors, canines and first premolars with optimal control of anchorage. Clinical cases are shown to illustrate the technique.

Long-term evaluation of maxillary molar position after distalization using modified C-palatal plates in patients with and without second molar eruption

INTRODUCTION

The purpose of this study was to analyze the treatment effects after molar distalization using modified C-palatal plates with and without second molar eruption and to evaluate the three-dimensional position of the molars during long-term retention using cone-beam computed tomography.

METHODS

The study sample comprised 74 third molars in 42 patients. Twenty-seven adolescent patients (mean age, 12.6 years) having 48 maxillary third molars were divided into 2 groups according to the eruption of their second molars: 15 patients with second molar eruption (group 1) and 12 patients without second molar eruption (group 2). Pretreatment, posttreatment, and long-term data (mean, 5.2 years) from cone-beam computed tomography were scanned and compared with control groups.

RESULTS

There was less tipping movement of the first and second molars (0.94° and 3.22°) and distal tipping movement of the third molars (8.91°) in group 1 than in group 2 (4.36°, 7.39°, and 3.08°, respectively), but the treatment time was shorter and the positional change of the third molars was insignificant in group 2. In the long-term, the second molars fully erupted after distalization in group 2, and there was no difference in the third molar position between group 1, group 2, and the control group, except for the vertical position of the third molars in group 1.

CONCLUSIONS

In the long-term, the second molars fully erupted after distalization, and the third molars were in a favorable position. Therefore, these findings suggest that clinicians do not need to extract developing third molars before distalization in adolescents.

Effect of second molar eruption on efficiency of maxillary first molar distalization using Carriere distalizer appliance

Introduction:

Maxillary molar distalization is a common approach for correcting dental Class II malocclusions.

Objective:

This study aimed at comparing the outcomes of maxillary first molar distalization using the Carriere appliance before and after second molar eruption.

Methods:

Two groups of patients with dental Class II malocclusions were treated with Carriere distalizer appliance with heavy rectangular mandibular wire and lingual arch for anchorage. Patients of the first group presented unerupted maxillary second molars during the distalization period. In the second group, maxillary second molars were in occlusion on treatment onset. Cone beam computed tomography images were taken at the beginning of treatment and after finishing molar distalization, to compare both groups regarding first molar distalization, intrusion, mesiodistal tipping, buccolingual torquing and rotation, anchorage loss and skeletal changes. Also, the treatment durations were compared.

Results:

The mean first molar distalization period in the first group (19.2 ± 1.6 weeks) was significantly smaller than the second group (23.3 ± 2.3 weeks). The amount of maxillary first molar distalization was significantly greater, while the amount of rotation was significantly smaller in the first group. No statistically significant differences in the amounts of maxillary first molar intrusion, mesiodistal tipping and buccolingual torquing between both groups was found. Mandibular incisor labiolingual torquing and mandibular first molar mesialization and mesiodistal tipping were significantly greater in the second group.

Conclusions:

Maxillary first molar distalization before maxillary second molar eruption is more efficient, with less anchorage loss than after second molar eruption.

Comparison of treatment effects from total arch distalization using modified C-palatal plates versus maxillary premolar extraction in Class II patients with severe overjet

INTRODUCTION

This study aimed to compare the skeletodental and soft tissue changes with total arch distalization using a modified C-palatal plate (MCPP) and maxillary first premolar extraction treatment in Class II malocclusion patients with severe overjet.

SETTING AND SAMPLE POPULATION

The sample consisted of 46 adult patients who had Class II Division 1 malocclusion with severe overjet; 25 of them received non-extraction treatment with MCPPs (age, 22.5 ± 7.2 years), and 21 received maxillary first premolar extraction treatment (age 23.4 ± 6.5 years).

METHOD

A total of 26 variables were measured on pre- and post-treatment lateral cephalograms. To evaluate the differences between pretreatment and post-treatment in each group, t tests and Wilcoxon rank-sum tests were used. To compare the amount of change between the two groups, MANOVA test was used.

RESULTS

The overjet was significantly reduced in the MCPP and extraction groups by 4.8 mm and 5.4 mm, respectively. However, the two groups had no significant difference in the sagittal, vertical and angular changes of the maxillary incisors. In addition, regarding soft tissue changes, the MCPP and extraction groups showed an increased nasolabial angle of 7.5° and 9.4°, decreased upper lip to the true vertical line of 1.8 mm and 2.2 mm, respectively (P < .001).

CONCLUSIONS

There was no significant difference in the skeletal changes between the MCPP and extraction groups, and the reduction in overjet was similar in the groups. These results suggest that MCPP might be a viable treatment option for total arch distalization in Class II malocclusion patients with severe overjet.

Efficiency of the skeletonized Pendulum K appliance for non-compliance maxillary molar distalization : A clinical pilot study

PURPOSE

Conventional anchorage with exclusively intraorally anchored appliances for non-compliance molar distalization combines a palatal acrylic button with periodontal anchorage. This type of anchorage is critically discussed because of the temporary hygienic impairment of the palate and the uncertain anchoring quality of the button. A purely dentally/periodontally anchored Pendulum K appliance was developed, which is exclusively anchored via four occlusal rests. The aims of this pilot study were to examine the suitability of the skeletonized Pendulum K for distalization of maxillary molars, and to investigate the quality of this alternative anchoring modality.

PATIENTS AND METHODS

In all, 10 patients received skeletonized Pendulum K appliances attached to all maxillary premolars for bilateral molar distalization. Supporting anchorage through an acrylic button adjacent to the anterior palate was not used. The pendulum springs were initially activated on both sides with a distalization force of 220 cN each and provided with uprighting and toe-in bends. The specific force/moment system was regularly reactivated intraorally by adjustment of the distal screw.

RESULTS

The study demonstrates the suitability of the skeletonized Pendulum K appliance for the distalization of maxillary molars (3.28 ± 0.73 mm). Side effects on the molars were slight distal tipping (3.50 ± 2.51°/PP, 3.00 ± 1.41°/SN) and mesial inward rotation (average 2.75 ± 7.50° and 4.50 ± 12.77°). Significant anchorage loss occurred in the form of mesialization of the incisors by 1.40 ± 0.82 mm and of the first premolars by 2.28 ± 0.85 mm.

CONCLUSION

The skeletonized Pendulum K appliance allows compliance-free upper molar distalization. Exclusively dental/periodontal anchorage resulted in a lower percentage of molar distalization compared to a conventional anchoring preparation of the Pendulum K with a palatal acrylic button. Anchorage loss had a comparatively stronger effect on the anchoring premolars but less on the incisors. Typical side effects on the molars such as distal tipping and mesial inward rotation were remarkably low.

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.

Total maxillary arch distalization with modified C-palatal plates in adolescents: A long-term study using cone-beam computed tomography

INTRODUCTION

The aims of this study were to evaluate the long-term skeletodental effects, the volume of maxillary tuberosity, and airway space changes after maxillary molar distalization using modified C-palatal plate (MCPP) in adolescents with Class II malocclusion.

METHODS

The sample consisted of 20 adolescent patients (MCPP group; mean age, 12.9 ± 1.0 year) who underwent bilateral distalization of their maxillary dentition and 20 subjects as a control group. In the MCPP group, cone-beam computed tomography images were taken before distalization, at the end of the treatment, and during retention with a minimum of a 3-year posttreatment follow up period. Repeated measures ANOVA followed by post-hoc analysis with the Bonferroni test were used to identify significant differences between time points.

RESULTS

After the long-term observation period, sagittal skeletal and dental relationships were maintained (there were no significant changes in ANB, occlusal plane angle, and overjet postretention). The vertical skeletal dimension did not change during treatment and was stable at the long-term follow-up (the mandibular plane angle and ANS-Me were relatively well maintained). The volume of the maxillary tuberosity showed no significant change during long-term retention. However, the volume was significantly smaller in the treatment group than in the control group (P <0.0001). There were no significant airway space changes after distalization and the postretention period. In addition, there was no significant difference between the MCPP and control groups.

CONCLUSIONS

Improved sagittal skeletal and dental relationships because of treatment were maintained in the long-term evaluation. There was no negative long-term effect on airway space associated with the maxillary arch distalization. Therefore, these findings might be beneficial for clinicians in diagnosis and treatment planning for Class II malocclusion in adolescents.

Dental and skeletal effects after total arch distalization using modified C-palatal plate on hypo- and hyperdivergent Class II malocclusions in adolescents

OBJECTIVES

To compare the dental and skeletal treatment effects after total arch distalization using modified C-palatal plates (MCPPs) on adolescent patients with hypo- and hyperdivergent Class II malocclusion.

MATERIALS AND METHODS

The study group included 40 patients with Class II malocclusion (18 boys and 22 girls, mean age = 12.2 ± 1.4 years) treated with MCPPs. Fixed orthodontic treatment started with the distalizing process in both groups. Participants were divided into hypo- or hyperdivergent groups based on their pretreatment Frankfort mandibular plane angle (FMA) ≤22° or ≥28°, respectively. Pre- and posttreatment lateral cephalograms were digitized, and 23 variables were measured and compared for both groups using paired and independent t-tests.

RESULTS

The hyper- and hypodivergent groups showed 2.7 mm and 4.3 mm of first molar crown distalizing movement, respectively (P < .001). The hypodivergent group had a slight 2.2° crown distal tipping of first molars compared with 0.3° in the hyperdivergent group. After distalization, the FMA increased 3.1° and 0.3°, in the hypodivergent and hyperdivergent groups, respectively (P < .001). SNA decreased in the hypodivergent group, while other skeletal variables presented no statistically significant differences in the changes between the groups.

CONCLUSIONS

The hypodivergent group showed more distal and tipping movement of the maxillary first molar and increased FMA than the hyperdivergent group. Therefore, clinicians must consider vertical facial types when distalizing molars using MCPPs in Class II nonextraction treatment.

A 3D finite element analysis of maxillary molar distalization using unilateral zygoma gear and asymmetric headgear

OBJECTIVE

The aims of this study were (a) to evaluate the displacement and stress distribution in the maxillary dentition associated with the use of two different unilateral distalization appliances-unilateral zygoma gear (UZG) appliance and asymmetric headgear (AHG)-in non-growing patients; and (b) to assess the effects of fully erupted maxillary third molars on the distalization of the first molar with both appliances by using three-dimensional finite element analysis.

SETTINGS AND SAMPLE POPULATION

Two 3D models of the maxilla were created: one with third molars and one without. Next, two distalizing appliances (UZG and AHG) were added to each model to create four models.

MATERIALS AND METHODS

Distalization forces were applied, and the resultant displacements were recorded at the mesiobuccal and distolingual cusps and palatal root apex of each molar and the incisal edge root apex of the central incisors. The resulting von Mises stress distributions were evaluated.

RESULTS

With the UZG, the first molar showed greater root distalization than the crown in the model with the third molar, whereas the model without the third molar showed distalization and distal tipping of the first molar. With the AHG, the first molar showed a large amount of distal tipping in the model without a third molar. However, this tipping was less than that in the model with third molars.

CONCLUSION

The presence of completely erupted third molars decreased the amount of uncontrolled distal tipping in both appliances. UZG can be considered as an effective option for maxillary molar distalization.

Time of maxillary molar distalization with non-compliance intraoral distalizing appliances: a meta-analysis

BACKGROUND/OBJECTIVE

To assess the mean maxillary molar distalization time with non-compliance intraoral distalizing appliances.

SEARCH METHODS AND SELECTION CRITERIA

Database search included PubMed, Web of Science, Scopus, The Cochrane Library, Lilacs, and a partial grey literature through Google Scholar and OpenGrey. The search was performed until May 2017 and updated on February 2019, without limitations regarding publication year or language. Controlled clinical trials (randomized and non-randomized prospective studies) reporting duration of maxillary molar distalization of Class II patients treated with intraoral distalizers were included.

DATA COLLECTION AND ANALYSIS

For the trials' quality assessment, the Cochrane Risk of Bias tool and the Cochrane Collaboration's ROBINS-I tool were used for the randomized controlled trials and non-randomized prospective studies, respectively. Database research, risk of bias (RoB) assessment, and extraction of data were performed by two independent investigators, with inclusion of a third reviewer, if disagreements emerged. Data was combined through a random-effects meta-analysis. Subgroup analyses regarding side of force application, type of anchorage, amount of molar distalization, and sensitivity analysis comparing study designs were also performed. Quality of evidence was assessed using the GRADE and SORT approaches.

RESULTS

Nine studies were included in the qualitative analysis; however, a meta-analysis was performed with only four studies, due to the presence of high RoB in the other studies. The random-effects meta-analysis assumes that the mean distalization time with distalizers is 8.34 months (95% confidence interval: 6.10, 10.58). Another meta-analysis was performed to evaluate the relationship between distalization time and the type of anchorage (conventional or skeletal), resulting in no significant difference. Both meta-analyses presented low-quality evidence.

LIMITATIONS

The major limitation of this meta-analysis is the fact that distalization time can be affected by a great range of factors.

CONCLUSIONS AND IMPLICATIONS

Correction of a half-to-full cusp Class II molar relationship with intraoral distalizers can be achieved in 8.34 months, and this distalization time may not be affected by the kind of anchorage used.

REGISTRATION

The protocol for this systematic review was based on the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 and was registered at PROSPERO database (http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42017068737). This systematic review is reported according to the PRISMA statement.

Maxillary dento-skeletal outcomes after orthopedic forward (class III) and backward (class II) traction in growing subjects

BACKGROUND

This retrospective study investigated the treatment effects produced by two orthopedic appliances, an extraoral orthopedic traction on Stephenson plate (SP) in skeletal Class II malocclusion and Delaire Facial Mask (FM) in skeletal Class III malocclusion.

METHODS

FM Group comprised 25 patients (13 males; 12 females, mean age 9.3 years, CS 1-2) undergoing Delaire Facial Mask therapy (mean treatment duration 1.5 years ± 1.2, 700-800 gr per side). SP Group comprised 24 patients (9 males; 15 females, mean age 10.5 years ± 1.9, CS 1-3) treated with extraoral orthopedic traction on Stephenson plate (mean treatment duration 1.6 years ± 0.8, 700-900 gr per side). For all subjects lateral cephalograms before (T0) and after (T1) therapy were obtained and traced. Descriptive statistics, t-test and Shapiro-Wilks test were calculated for each variable.

RESULTS

A mesial movement of the maxillary bone of 2.4 mm in the FM group and a distal movement in the PS group (0.4 mm) was found. SNA° was reduced 1.4° after SP and increased 0.7° after FM. The overjet decreased by 4 mm after SP, while it grew after FM by 2.4 mm, as well as molars relationships (4.5 vs. 0.8 mm).

CONCLUSIONS

Facemask induced greater skeletal movements than extraoral traction on Stephenson plate. PS produced a limited downward movement of the whole maxilla together with notable incisors and molars back corrections. Based on our results, it could be speculated that orthopedic mesial traction of maxillary bone may result easier than the distal movement.

Stability of Class II malocclusion treatment with the distal jet followed by fixed appliances

INTRODUCTION

This retrospective study aimed to assess the stability of Class II malocclusion treatment with the distal jet, followed by fixed appliances.

METHODS

Seventy-five cephalograms of 30 subjects were divided into 2 groups. The treated group consisted of 15 patients who were evaluated at the pretreatment, posttreatment, and long-term posttreatment stages. The control group consisted of 15 subjects with normal occlusion, comparable to the experimental group at the long-term posttreatment period. Intergroup comparison of posttreatment changes was evaluated with t tests.

RESULTS

In the long-term posttreatment period, there was no significant change in the anteroposterior position of the maxilla and mandible to the cranial base. The lower anterior face height had a significantly smaller increase in the treated than in the control group. The maxillary molars in the treated group had significantly smaller vertical development, and the mandibular incisors had significantly greater labial tipping and protrusion than the control group. The treatment produced significant improvement in molar relationship and reduction of overbite and overjet, which remained stable in the long-term posttreatment period. There was greater upper lip protrusion in the experimental than in the control group in the long-term posttreatment period.

CONCLUSIONS

Treatment of Class II malocclusions with the distal jet, followed by fixed appliances, showed good long-term stability in molar relationship, overbite, and overjet.

Transverse stability of Class II malocclusion correction with the pendulum appliance

INTRODUCTION

This study aimed to evaluate the stability of transverse changes after Class II malocclusion correction with the pendulum fixed distalizer, followed by preadjusted edgewise fixed orthodontic appliances.

METHODS

This longitudinal study was conducted in the maxillary dental casts of 20 Class II malocclusion subjects (mean age, 12.5 years; 14 females and 6 males). Eighty 3-dimensional maxillary dental casts were analyzed; 20 at the beginning of treatment, 20 after distalization, 20 after edgewise appliance debonding, and 20 at 5 years posttreatment. Maxillary transverse distances between canines, first premolars, second premolars, first molars, and second molars were analyzed using Geomagic Studio 5 (3D Systems, Rock Hill, SC).

RESULTS

There were no significant changes in intercanine distance during and after treatment. There were significant interfirst and intersecond premolar distance increases during treatment. There were significant interfirst and intersecond molar distance increases during the distalization phase. However, there were significant decreases in these distances at the end of treatment. There were no significant long-term posttreatment changes.

CONCLUSIONS

The intercanine distance remains stable during and after treatment. The interfirst and intersecond premolar distances significantly increase during treatment and remain stable after treatment. The interfirst and intersecond molar distances increase during the distalization phase, decrease at the end of treatment, and remain stable after treatment.

Comparison of Treatment Effects with Modified C-Palatal Plates vs Greenfield Molar Distalizer Appliances in Adolescents

Objectives: The aim of study was to evaluate skeletodental and soft tissue treatment effects and the amount of maxillary molar distalization with modified C-palatal plates vs. Greenfield molar distalizer appliances in adolescents. Study design: The samples consisted of pre- and posttreatment lateral cephalograms collected from 39 patients with Class II malocclusion. The MCPP group was comprised of 21 patients (mean age: 11.7 ± 1.3 years) treated with MCPP appliances while the GMD group included 18 patients (mean age: 11.2 ± 0.9 years) treated with GMD. Fixed orthodontic treatment started with the distalization process in both groups. From each cephalograpm, twenty-nine variables were measured for analysis and then the two groups were compared. Descriptive statistics, a paired t-test, and multivariate analysis of variance were performed to compare the treatment effects within and between the groups. Results: There was significant treatmentrelated change in the sagittal position of the maxilla and the mandible within each group. However, there were no statistically significant inter-group differences. The mean maxillary first molar distalization was 3.96 mm in the MCPP group vs. 2.85 mm in the GMD group. Both groups showed minimal distal tipping, but the maxillary incisors were significantly extruded by 3.04 ± 0.89 mm (P < .001) in GMD group. There was no significant difference in treatment duration between the groups. Conclusions: The maxillary first molars of both the MCPP and GMD groups were effectively distalized and there were significant skeletal changes in the maxilla. However, the maxillary incisors were significantly extruded in the GMD group.

Long-term stability of miniscrew anchored maxillary molar distalization in Class II treatment

OBJECTIVE

To investigate treatment stability of miniscrew-anchored maxillary distalization in Class II malocclusion.

MATERIALS AND METHODS

This retrospective study included a distalization (n = 19) and a control (n = 19) group; a patient group with minor corrections served the control. Lateral cephalograms of 38 adult patients were taken before (T0), immediately after (T1), and 3-4 years after (T2) treatment. Horizontal and vertical movement and tipping of the maxillary first molars (U6) and central incisors (U1) were measured along with skeletal craniofacial parameters at three time points to compare the two groups regarding the achieved treatment effects and their stability.

RESULTS

Total arch distalization therapy led to 4.2 mm of distal movement of U6 without distal crown tipping (0.6° of axis change) and 3.3° of occlusal plane steepening. Over an average retention period of 42 months, maxillary total arch distalization provided high stability of treatment results, showing the same amount of mesial movement (0.7 mm) as the control group.

CONCLUSIONS

In Class II treatment, miniscrew-anchored maxillary total arch distalization can provide stable distal movement of the maxillary first molars and central incisors.

Dentoskeletal Class II Malocclusion: Maxillary Molar Distalization with No-Compliance Fixed Orthodontic Equipment

Dentoskeletal class II malocclusion due to a protruded upper dental arch is a major reason for an orthodontic treatment. In these cases, the correction of class II can be hindered by molar distalization, obtained with 'no-compliance therapy' that involves the use of appliances which minimize the need for such co-operation and attempt to maximize the predictability of results. The aim of this review was to outline the effectiveness of no-compliance fixed orthodontic devices in the molar distalization. After selection according to the inclusion/exclusion criteria, 16 articles from 2000 to 2019 were qualified for the final analysis. The literature shows various no-compliance fixed devices whose effect is to distalize the maxillary molars. The present revision allows to conclude that there is a need to increase the number of studies, especially with regard to the most recently introduced devices in the literature. The analysed studies allow to hypothesize that these appliances act with a minimal variability of molar distalization and disto-inclination among them, although different effects among the appliances can be observed as regards to the anchorage.

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.

Distalization with a modified C-palatal plate for severe upper crowding and a missing lower incisor

This case report presents the orthodontic treatment of a 25-year-old patient with skeletal Class II and severe maxillary arch crowding, moderate mandibular arch crowding, anterior crossbite, and a missing lower incisor. He was treated with molar distalization using a modified C-palatal plate and temporary anchorage devices to create sufficient space for retraction. The total treatment duration was 21 months. After treatment, his occlusion and smile esthetics showed significant improvement. The modified C-palatal plate represents a treatment modality that enhances the prospects of non-extraction treatment and reduces the need for extraction.

Evaluation of the effects of the hybrid Pendulum in comparison with the conventional Pendulum appliance

OBJECTIVE

To evaluate the anchorage control and distalization of maxillary molars with the hybrid Pendulum appliance and to compare the results with a conventional Pendulum appliance.

MATERIALS AND METHODS

This study was carried out on the pre-(T0) and post-(T1) treatment lateral cephalograms and dental casts of 43 patients with Angle Class II molar relationships who were treated with conventional or hybrid Pendulum appliances. The hybrid Pendulum (HP) group consisted of 22 patients (14 females; eight males; mean age 14.3 ± 2.43 years) and treatment results were compared with a conventional Pendulum appliance (CP) group, which consisted of 21 patients (15 females; six males; mean age 14.6 ± 3.39 years). Intragroup comparisons were made with Wilcoxon test and intergroup comparisons were made with Mann-Whitney U-test (P < .05).

RESULTS

The mean distalization duration was 0.70 ± 0.25 years in the HP group and 0.83 ± 0.4 years in the CP group. Maxillary first molars showed significant distal movement and tipping of 4.25 mm and 9.09° in the HP group, and 3.21 mm and 9.86° in the CP group. Loss of anchorage at the first premolars was significantly smaller in the HP appliance group compared to CP group. The second premolars distalized spontaneously in the HP group while they mesialized significantly in the CP group. Proclination and protrusion of maxillary incisors were greater with the CP appliance compared to the HP appliance.

CONCLUSIONS

Maxillary molar distalization was achieved with both appliances. Mesialization of the anchorage unit was controlled successfully with the hybrid Pendulum; however, the conventional Pendulum appliance caused anchorage loss.

Comparison of the Pendulum appliance and the Jones Jig: A prospective comparative study

Objective:

To compare two molar distalization devices, the Pendulum appliance (PA) and the Jones Jig (JJ) in dental Class II patients.

Materials and Methods:

Pretreatment and postdistalization lateral cephalograms and study models of 20 subjects (6 males, 14 females) Class II malocclusion subjects were examined. PA and JJ group both consisted of 10 patients each with a mean pretreatment age of 12 years 1 month for females and 12 years 5 months for males. The PA and the JJ appliance were activated once in a month until Class II molar relationship was corrected to a super Class I molar relationship in both groups. Initial and final measurements and treatment changes were compared by means of Paired t-test.

Results:

Maxillary first molar distalized an average of 3.85 mm in the PA and 2.75 mm in the JJ between T1 and T2; rate of molar distalization was 1.59 mm/month for PA, and the JJ appliance averaged 0.88 mm/month, distal molar tipping was greater in PA (6.2°) than in the JJ (3.9°). Average mesial movement of the premolars was 2.2 mm with PA and JJ both. JJ showed a greater rotation of first molars after distalization as compared to PA. The increase in vertical facial height was also greater for JJ as compared to PA.

Conclusions:

Both the appliances were effective in molar distalization with PA requiring less distalization time (16 days less than JJ). Some adverse effects were noted with both which one should strive to control.

Maxillary molar distalization using conventional versus skeletal anchorage devices: A systematic review and meta-analysis

INTRODUCTION

The purpose of this study was to systematically review the evidence regarding conventional versus skeletal anchorage devices for molar distalization.

METHOD

An electronic search was conducted. Hand searching was done in the reference lists of included studies and some journals. Studies comparing conventional and skeletal anchorage for molar distalization in Angle class I or II malocclusions were assessed. Presence of periodontal disease, second or third molar extraction and application of tooth accelerating methods led to exclusion of studies. Generic-inverse variance approach was used for meta-analysis by use of the mean difference and random-effect model. Risk of bias was evaluated in included studies.

RESULTS

A total of 1996 articles were found; of which, 1991 were excluded. The mean amounts of molar distalization/tipping in skeletal anchorage and conventional anchorage groups were 5.35mm/8.44° and 4.25mm/8.31°, respectively, which were not significantly different. The mean amounts of premolar movement in skeletal anchorage and conventional anchorage groups were -0.96mm and +2.21mm, respectively, which was statistically significant (P=0.004). Duration of treatment in skeletal anchorage and conventional anchorage groups was 8.23 months and 7.95 months, respectively, which were significantly different (P=0.0001). Risk of bias was assessed to be high.

CONCLUSION

The conventional and skeletal anchorage devices were not significantly different in terms of the amount of molar distalization/tipping. However, the anchorage loss was lower in the skeletal anchorage group. The treatment time was shorter in the conventional anchorage group. More studies with proper design are required.

Evaluation of Dentoalveolar and Dentofacial Effects of a Mini-Screw-Anchored Pendulum Appliance in Maxillary Molar Distalization

Objective

The aim of this study was to evaluate the dentoalveolar and dentofacial effects of a mini-screw-anchored pendulum appliance in maxillary molar distalization.

Methods

Twenty patients with the Angle Class II molar relationship (mean age 14.05±2.4 years) were treated with a mini-screw-anchored pendulum appliance for molar distalization. A mini-screw 1.9 mm in diameter and 9 mm in length was used to support the pendulum appliance. The springs of the pendulum appliance were activated at 90° and exerted 250-300 gr force per side. Lateral cephalometric radiographs and dental cast models were obtained from all the patients before and after maxillary molar distalization.

Results

A 0.6° increase in the SNA and SNB angles, and a 0.3° decrease in the SN/GoGn angle were found to be statistically significant. In the maxillary first molars, 4.2-mm significant distalization, 0.6-mm significant intrusion, and 8.9° significant distal tipping were observed. The spontaneous distal drift of the maxillary second premolars was found to be statistically significant. In the maxillary first premolar and incisor positions, significant mesialization was observed; however, the changes in the angles of these teeth were found to be insignificant.

Conclusion

A mini-screw-anchored pendulum appliance is an effective method for maxillary molar distalization that controls the undesired anchorage loss observed in conventional methods.

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.

Molar distalization with 2K appliance: one-year follow-up

Correction of class II molars in growing patients with acceptable facial profile can be performed by distalization of maxillary first molars. However, in patients where compliance is difficult intraoral means of molar distalization is required. This case report describes the use and effectiveness of a novel 2K appliance in an 11-year-old female having an orthognathic profile, skeletal Class I relation, and Angle's Class II division 1 malocclusion with crowding of 8 mm and 3 mm in the maxillary and mandibular arches, respectively. Nonextraction treatment was planned with bilateral distalization of the maxillary first molars. The amount of distalization achieved by 2K appliance was 3.5 mm with only 1° distal tipping. The 2K appliance required minimal patient cooperation, produced bodily movement of molars with minimal tipping/rotation, and prevented anchorage loss of the anterior teeth. This 2K molar distalization appliance was found to be an effective technique to control molars in all three planes of space.

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.

The effect of first and second premolar extractions on third molars: A retrospective longitudinal study

OBJECTIVES

To analyse the effect of first and second premolar extractions on eruption space for upper and lower third molars and on third molar position and angulation during orthodontic treatment.

METHODS

The sample consisted of 296 patients of which 218 patients were orthodontically treated without extraction and 78 patients with extraction of first or second premolars. The eruption space for third molars was measured on pre- and posttreatment lateral cephalograms, whereas the angulation, vertical position, the relation with the mandibular canal and the mineralization status of third molars were evaluated using pre- and posttreatment panoramic radiographs. All data were statistically analyzed.

RESULTS

The increase in eruption space and the change in vertical position of upper and lower third molars significantly differed between patients treated with and without premolar extractions, whereas the change in angulation, relationship with the mandibular canal and mineralization status of the third molars did not significantly differ between patients treated with and without premolar extractions.

CONCLUSIONS

The retromolar space and the position of third molars significantly change during orthodontic treatment in growing patients. Premolar extractions have a positive influence on the eruption space and vertical position of third molars, whereas they do not influence the angular changes of third molars. Due to the retrospective character of the study, these conclusions should be carefully considered. Further prospective research is necessary for better insights into this complex topic.

CLINICAL SIGNIFICANCE

This study stresses the importance of considering the possible effects of orthodontic treatment on third molars during treatment planning.