Maxillary Molar Distalization Research Articles

Vertical Control in Molar Distalization by Clear Aligners: A Systematic Review and Meta-Analysis.

Background: Molar distalization is used to correct molar relationships or to create space for mild anterior crowding. However, whether clear aligners can provide proper vertical control with the sequential distalization strategy has been highly debated. Thus, the current study aimed to systematically review the amount of dentoskeletal changes in the vertical dimension that results from sequential molar distalization in clear aligner therapy without temporary anchorage devices (TADs). Methods: Registered with PROSPERO (CRD42023447211), relevant original studies were screened from seven databases and supplemented by a manual search by two investigators independently. Articles were screened against inclusion and exclusion criteria, and a risk of bias assessment was conducted for each included article. Relevant data were extracted from the included articles and meta-analysis was performed using RStudio. Results: Eleven articles (nine for maxillary distalization and two for mandibular distalization) were selected for the final review. All studies have a high or medium risk of bias. For maxillary molar distalization, the meta-analysis revealed 0.26 mm [0.23 mm, 0.29 mm] of maxillary first molar intrusion based on post-distalization dental model analysis, as well as 0.50 mm [-0.78 mm, 1.78 mm] of maxillary first molar intrusion and 0.60 mm [-0.42 mm, 1.62 mm] of maxillary second molar intrusion based on post-treatment lateral cephalometric analysis. Skeletally, there was a -0.33° [-0.67°, 0.02°] change in the SN-GoGn angle, -0.23° [-0.30°, 0.75°] change in the SN-MP angle, and 0.09° [-0.83°, 1.01°] change in the PP-GoGn angle based on post-treatment lateral cephalometric analysis. There was insufficient data for meta-analysis for mandibular molar distalization. Conclusions: No significant changes in vertical dimension were observed, both dentally and skeletally, after maxillary molar distalization with a sequential distalization strategy. However, further studies on this topic are needed due to the high risk of bias in the currently available studies.

Dentoskeletal changes during maxillary molar distalization using a skeletally anchored appliance

Dentoskeletal changes during maxillary molar distalization using a skeletally anchored appliance

Bilateral distalization of maxillary first molars in a group of adult patients after extraction of maxillary second molars using infra-zygomatic mini-implants: A prospective clinical trial

It is now possible to predictably distalize maxillary first molars in nongrowing patients with the infra-zygomatic gear distalizer and to improve malocclusions without having to extract the premolars and regardless of the patient's compliance. The purpose of this study was to investigate the amount and rate of distal movement of the maxillary first molars using our proposed appliance after extraction of maxillary second molars. Ten nongrowing female patients successfully treated with our proposed appliance were the subjects of this study. The amount, rate, and type of distalization, were analyzed through upper jaw cone beam computed tomography (pre- and post-treatment) and scanned casts taken on a monthly interval. The average amount of distalization of the maxillary first molars was 4.03 mm at the crown level and 2.88 mm at the root level. The rate of distalization had an average of 0.61 mm per month with a maximum of 0.79 mm in the first month because of the regional acceleratory phenomena after extracting the maxillary second molar. The maxillary first molars were distalized in a significant manner and all patients reached a Class I relation within an average duration of 6.4 months. The proposed appliance proved to be a viable noncompliance modality to distalize maxillary first molars correcting maxillary Class II malocclusions characterized by maxillary protrusion or maxillary incisor crowding.

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

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

Comparison of Dental and Skeletal Effects Of Miniscrew Supported Pendulum and Beneslider Appliances in Maxillary Molar Distalization: A Pilot Study

Comparison of Dental and Skeletal Effects Of Miniscrew Supported Pendulum and Beneslider Appliances in Maxillary Molar Distalization: A Pilot Study

Influence of maxillary molar distalization with clear aligners on three-dimensional direction: molar distal movement, intrusion, distal tip and crown buccal torque

BackgroundThe aim of this study was to evaluate the distal movement, vertical movement, distal tipping and crown buccal torque of maxillary molars after the completion of distalization by comparing the predicted movement with the achieved movement using palatal rugae registration.MethodsThe study included 22 clear aligner patients (7 males and 15 females), and 79 molars were measured. Two digital models were generated before treatment and after molar distalization and were superimposed after selecting the palatal rugae area for registration in GOM inspect suite software 2022 (GOM; Braunschweig, Germany). The predicted and achieved movements of molar distalization, intrusion, distal tip and crown buccal torque were measured and compared.ResultThe achieved distalization (1.25 ± 0.79 mm vs. 2.17 ± 1.03 mm, P < 0.001; 1.41 ± 1.00 mm vs. 2.66 ± 1.15 mm, P < 0.001), intrusion (0.47 ± 0.41 mm vs. 0.18 ± 0.54 mm, P < 0.01; 0.58 ± 0.65 mm vs. 0.10 ± 1.12 mm, P < 0.01), distal tip (5.30 ± 4.56° vs. 1.53 ± 2.55°, P < 0.001; 4.87 ± 4.50° vs. − 1.95 ± 4.32°, P < 0.001) and crown buccal torque (1.95 ± 4.18° vs. − 1.15 ± 4.75°, P < 0.001; 0.43 ± 4.39° vs. − 4.27 ± 6.42°, P < 0.001) were significantly different from the predicted values in the two groups (first molar, second molar). Significant regression relationships were found between the achieved distal movement and deviational intrusion (R2 = 0.203, P < 0.0001), distal tip (R2 = 0.133, P < 0.001) and crown buccal torque (R2 = 0.067, P < 0.05). There was a significant correlation between the deviational movements of intrusion and the distal tip (R = 0.555, P < 0.0001).ConclusionApproximately 2 mm maxillary molar distalization was achieved in this study. Deviational movement of intrusion, distal tip and crown buccal torque beyond the clear aligner virtual design appeared to a certain degree after distalization. Thus, more attention should be given to molar intrusion and distal tip and crown buccal torque as the designed distalization increases.

Biomechanical analysis of miniscrew-assisted molar distalization with clear aligners: a three-dimensional finite element study.

To compare the biomechanical characteristics of maxillary molar distalization with clear aligners in conjunction with three types of miniscrew anchorage. Three-dimensional (3D) finite element models of maxillary molar distalization with clear aligners and three types of miniscrew anchorage were established, including (A) control group, (B) direct buccal miniscrew anchorage group, (C) direct palatal miniscrew anchorage group, and (D) indirect buccal miniscrew anchorage group. The 3D displacement of maxillary teeth and the principal stress (maximum tensile and compressive stress) on the root and periodontal ligament (PDL) during molar distalization were recorded. The tooth displacement pattern during maxillary molar distalization in the four groups showed similarities, including labial tipping of anterior teeth, mesial and buccal tipping of premolars, and distal and buccal tipping of molars, but with varying magnitudes. Group C exhibited the greatest molar distalization, with the first molar achieving 0.1334 mm of crown distalization. Group D demonstrated a notable buccal crown movement (0.0682 mm) and intrusion (0.0316 mm) of the first premolar. Compared to Groups A and B, Groups C and D showed less labial crown tipping of the central incisor. Group B showed the greatest amount of maxillary incisor intrusion (central incisor: 0.0145 mm, lateral incisor: 0.0094 mm). Moreover, Groups C and D displayed significantly lower levels of compressive and tensile stress in the roots and PDL of the maxillary central and lateral incisors. Molar distalization is a dynamic process involving sequential tooth movement stages; however, our research primarily examined the tooth movement patterns in the initial aligner. The use of miniscrew anchorage, especially direct palatal miniscrew anchorage, may enhance the treatment efficacy of maxillary molar distalization with clear aligners, leading to increased molar distalization, reduced mesial movement of premolars, and minimized labial tipping of anterior teeth.

Predictability of Dental Distalization with Clear Aligners: A Systematic Review.

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

Biomechanical effects of different staging and attachment designs in maxillary molar distalization with clear aligner: a finite element study

BackgroundIn the present study, the effects of distalizations of one and two molars with different step distances and attachment designs have been analyzed.MethodsA 3D finite element analysis model has been developed in order to determine the tendency of tooth displacement and stress distribution with clear aligner treatment.ResultsUnder the condition of single-molar distalization, when the step distance was set to 0.25 mm, the total displacement was 0.086 mm for central incisors, 0.080 mm for lateral incisors, 0.084 mm for canines, 0.102 mm for the first premolar and 0.076 mm for the second premolar. The von Mises stress of roots and the principal stress of the periodontal ligament was slightly lower than in the control group when the step distance was set to 0.130 mm. Under the condition of two-molar distalization, when the step distance was set to 0.130 mm, the total displacements for central incisors, lateral incisors and canines as well as both the first and second maxillary molars were basically the same as with a distance of 0.250 mm for one-molar distalization. In addition, when the step distance was 0.130 mm with two-molar distalization, the rotation center of the first and second molar was closer to the apex of the root indicating that the smaller step distance led to more bodily movement during the two-molar distalization. However, displacement tendencies of the first molar and the second molar were basically the same whether horizontal or vertical rectangular attachments were added.ConclusionsA step distance of moving two molars to 0.130 mm can achieve the same reaction force on the anterior teeth as moving one molar 0.250 mm without effects on horizontal or vertical rectangular attachments.Clinical relevanceOur results provide a theoretical basis and guidance for simultaneously moving two molars backward in clinical practice using a clear aligner.

Measurement of the rate of maxillary molar distalization using steel bar distalizer

Measurement of the rate of maxillary molar distalization using steel bar distalizer

Effect of low-level laser therapy on pain reduction in orthodontic patients during molar distalization: A randomized controlled trial

AimTo investigate the effects of low-level laser therapy (LLLT) on pain reduction in orthodontic patients during molar distalization. Materials and methodsTwenty patients requiring bilateral maxillary first molar distalization were randomly assigned to two groups: the intervention group (mean age 15.61 ± 1.03 years) received multiple LLLT after every activation of the distalizing appliance (immediately and on the 3rd, 7th, and 14th days) and the control group (mean age 15.64 ± 1.08 years) who did not receive LLLT. Patients reported pain levels every day for 7 days following activation of the appliance using an 11-point numeric rating scale (NRS), then the pain experience of both the intervention and control groups was compared using Mann-Whitney U test. ResultsThe mean pain scores on the 1st day were higher in the intervention group (9.27 ± 1.01) compared to that of the control group (8.80 ± 1.03). However, the mean pain scores of the intervention group (6.55 ± 1.29, 4.00 ± 1.26, 2.55 ± 1.29, 0.91 ± 1.04, 0.00 ± 0.00 and 0.00 ± 0.00, respectively) were lower than the control group (7.40 ± 1.90, 5.60 ± 2.07, 4.20 ± 1.99, 2.80 ± 1.93, 1.60 ± 1.58 and 0.40 ± 0.84, respectively) from the 2nd to the 7th day. All the differences were not statistically significant except on the 6th day (P-value = 0.003). The peak pain level was experienced by both groups on the 1st day, followed by a statistically significant gradual decrease in pain levels. Patients in the intervention group reported a shorter overall duration of pain. ConclusionAlthough LLLT, with the used parameters, reduced the overall duration of pain experience following maxillary first molar distalization, it was not effective during peak pain levels.

Does maxillary sinus proximity affect molar root resorption during distalization using Invisalign? a CBCT study

BackgroundThis study aimed to assess the correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption during molar distalization using clear aligner therapy (CAT).Materials and methodsThirty-eight cone beam computed tomography scans (CBCTs) obtained pre- (T0) and post-treatment (T1) from 19 adult patients (36.68 ± 13.50 years), who underwent maxillary molar distalization using Invisalign® aligners (Align Technology, Inc., San José, CA, USA) with a minimum of 2 mm distalization, were evaluated in this study At least 22 h of aligner wear per day was a main inclusion criterion. Sinus proximity and changes in root lengths were measured for 61 molars (183 roots). Spearman coefficient analysis was used for assessing correlation between sinus proximity and root resorption. The level of significance was set at p ≤ 0.05. The reproducibility of measurements was assessed by intraclass correlation coefficient (ICC).ResultsSpearman coefficient revealed no significant correlation between sinus proximity and molar root resorption for mesiobuccal, distobuccal or palatal roots (p = 0.558, p = 0.334, p = 0.931, respectively).ConclusionThere was no correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption.

Effectiveness of miniscrew-supported maxillary molar distalization according to temporary anchorage device features and appliance design: systematic review and meta-analysis.

To evaluate the effectiveness of distalizing maxillary first molars (U6) by temporary anchorage devices (TADs) according to their location (palatal, buccal, and zygomatic), their number, and appliance design. An electronic search of maxillary molar distalization with TADs was done through April 2023. After study selection, data extraction, and risk-of-bias assessment, meta-analyses were performed for the extent of distalization, distal tipping, and vertical movement of U6 using the generic inverse variance and random-effects model. The significance level was set at 0.05. Forty studies met the inclusion criteria: 4 randomized controlled trials (RCTs), 13 prospective studies, and 23 retrospective studies (total of 1182 patients). Distalization of the U6 was not significantly greater (P = .64) by palatal (3.74 mm) and zygomatic (3.68 mm) than by buccal (3.23 mm) TADs. Distal tipping was significantly higher (P < .001) in nonrigid (9.84°) than in rigid (1.97°) appliances. Vertical movement was mostly intrusive and higher but not significantly different (P = .28) in zygomatic anchorage (-1.16 mm). Distalization of U6 with TADs can be an effective and stable treatment procedure, especially when performed with rigid palatal appliances. However, further RCTs or prospective cohort studies are strongly recommended to provide more clinical evidence.

En-masse Distalization of Maxillary Arch with Modified Hybrid Hyrax Appliance: A Case Report

Class II malocclusion is one of the most commonly seen malocclusions in the orthodontic practice, with a variety of treatment modalities found in the literature. Maxillary molar distalization is a one of treatment options of dental Class II patients with excessive overjet, anterior crowding, or both. However, a commonly seen side effect in the conventional distalization devices is anchor loss. Here, in this case report, we have shown the successful treatment of a Class II malocclusion patient with a new concept of modified placement of the hybrid hyrax appliance, which was used effectively for en-masse, bodily distalization of maxillary teeth, with no anchorage loss. Also, the same appliance could be used for retention after the active distalization period till the treatment completion.

Actual contribution ratio of maxillary and mandibular molars for total molar relationship correction during maxillary molar sequential distalization using clear aligners with Class II elastics: A finite element analysis

Class II elastics, in combination with clear aligners (CA), are efficient for molar distalization. However, the effects of this combination on intermaxillary molar relationship correction have yet to be investigated. This study aimed to investigate the actual contribution ratio of the maxillary and mandibular molars for total molar relationship correction during maxillary molar distalization using Class II elastics with CA and further explore therapeutic recommendations for clinical practice. Finite element models (FEMs) were established, including the distalization of the second molars (Set I), followed by the distalization of the first molars (Set II). Model A simulated elastics attached by precision cutting, whereas Model B simulated elastics attached to buttons. Force magnitudes of 100 g, 150 g, and 200 g of force were applied. We recorded the contribution ratio of the maxillary and mandibular molars for total molar relationship correction, effective distalizing distance in 0.25 mm step distance, tipping and rotation angles, and the hydrostatic stress in the periodontal ligament. During maxillary molar distalization, mesialization of the mandibular molar had a notable contribution ratio for molar relationship correction. The mandibular first molar was mesialized with mesiolingual rotation tendency. Approximately half of the 0.25 mm step distance was occupied by maxillary molar distalization; the remainder was occupied by anchorage teeth mesialization and tipping or rotation. When traction forces increased, the total molar relationship correction and effective distalization increased; the mandibular molars mesialization contribution ratio also increased, as did rotation and inclination tendency. Precision cutting had a higher total molar relationship correction and more effective distalization than a button but also had a larger contribution ratio of mandibular molar mesialization and inclination or rotation. Mandibular molar mesialization should be considered when correcting the molar relationship using CA with intermaxillary elastics during maxillary molar distalization. It is also important to consider the anchorage teeth mesialization and undesired tipping or rotation.

Evaluation of Dentoskeletal and Profile Changes with Distal Jet in Moderate Skeletal Class II Patients

In an orthodontic treatment, upper molar distalization is mandatory to gain space in upper arch. Objective: To evaluate the nature of molar distalization &amp; its effects on soft tissue profile, dentoalveolar structures &amp; skeletal structures. Methods: This was a retrospective study design. 20 subjects were found to be eligible for the distalization with average age of 19.4 yrs. Only Distal jet was used for distalization and one operator was there for all the subjects. Pre and post treatment cephalograms were taken to analyze dentoalveolar &amp; soft tissue changes. Paired sample T test was used. Results: Notable amount of molar distalization and increased lower face height was achieved. Conclusions: This study verified definite distalization of maxillary first molars using distal jet showing a better bodily movement with less tipping movement, with certain unwanted &amp; reactionary effects on incisor position &amp; limited effects on facial soft tissues.

Three-Dimensional Force Characterizations in Maxillary Molar Distalization: A Finite Element Study

Class II malocclusion is a very common condition in orthodontic patients. The reaction force and moment on the teeth induced by a maxillary segmental distalizer (MSD) are essential for understanding tooth movement, tipping, and rotation. This work quantified the three-dimensional (3D) reaction force and moment on canine and molar teeth induced by three different MSDs: the JVBarre (JVB), Carriere Motion 3D (CM3D), and CM3D Clear. A patient-specific mandibular model was reconstructed based on cone-beam computed tomography (CBCT) images. Each of the three MSDs was implanted using finite element analysis (FEA). The reaction force and moment were obtained. The results show that the JVB induced less extrusion force (15% less), tipping (90% less), and rotational moment (70% less) on the canine, compared with the other two CM3Ds. However, the JVB induced a relatively larger extrusion force, tipping, and rotational moment on the molar due to the hook location changing from the end to the middle of the bar. These observations were consistent with the 3D stress distribution of the MSDs. The mechanical understanding from this work may shed light on the optimal design of MSDs.

Driving the maxillary molar distally with infra-zygomatic crest implant: A case report

There has been increase in the treatment modalities for non-surgical Class II malocclusion. This has resulted in orthodontists becoming more vigilant with extraction treatment plans and exploring possible non-extraction treatment approaches. Maxillary molar distalization is one such method. The maxillary molar is distalized to create space and helps in solving the malocclusionMany appliance were used for the distalization of molars over the period of time. Both intra-oral and extra-oral methods are present. The extra oral appliance includes headgear and heavy elastics; whereas intra oral appliance include distal jet, jones jigs, pendulum appliance, k-loop, fixed functional appliances, magnets, ACCO appliance and use of TAD’s. Thus the use of IZC implants has been effective in distalization of molars.

Maxillary total arch distalization with infra-zygomatic crest (IZC) bone screws for the correction of skeletal class II malocclusion: A case report

The correction of skeletal malocclusions in orthodontics has always been a contest for clinicians, especially in non-growing individuals, and often necessitates the distalization of maxillary or mandibular skeletal bases. To accomplish this, diverse treatment modalities have been employed by researchers, and the most recent one is the use of extra-alveolar bone screws such as Infra-zygomatic Crest (IZC) implants. Unlike conventional methods such as extraction and orthognathic surgery, this technique is an effective and efficient treatment alternative for predictable total arch distalization in borderline surgical cases, without interfering with the root movements and with minimal dependence on patient compliance. For achieving the displacement of teeth in a bodily controlled manner, an appropriate direction and magnitude of force must be carefully chosen. Therefore, this case report attempts to measure the amount and pattern of maxillary molar distalization using Infra-zygomatic Crest (IZC) implants with long power arms as a workable treatment option, in an 18-year-old female patient with a skeletal Class II pattern, with no extra mini-implants in the anterior region for intrusion.

The effect of maxillary molar distalization with clear aligner: a 4D finite-element study with staging simulation

IntroductionLong-term simulation of tooth movement is crucial for clear aligner (CA) treatment. This study aimed to investigate the effect of maxillary molar distalization with CA via an automatic staging simulation.MethodA finite-element method (FEM) model of maxillary dentition, periodontal ligaments, attachments, and corresponding CA was established, and a prescribed 2-mm distalization with 0.1 mm each step of the second molar was simulated. The long-term tooth movement under orthodontic force was simulated with an iterative computation method. The morphologic changes of CA during staging were simulated with the thermal expansion method.ResultsTwenty steps of molar distalization were simulated. Significant distal tilting of the second molar was revealed, along with the proclination of anterior teeth, which caused the ‘reversed bow effect’. For the second molar, 4.63°distal tilting at the 20th step was revealed. The intrusion of the incisors and the second molar were 0.43 mm, 0.39 mm, and 0.45 mm, respectively, at step 20. All the anterior teeth showed a proclination of approximately 1.41°–2.01° at the 20th step. The expression rate of the designed distalization of the second molar was relatively low (approximately 68%) compared to the high efficacy of interdental space opening between molars with CA (approximately 89%).ConclusionA novel method of simulating long-term molar distalization with CA with FEM was developed. The FEM results suggested distal tilting of the second molar and the proclination of anterior teeth during the molar distalization.