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

The effectiveness of the total-maxillary-arch-distalization approach in treating class II division 1 malocclusion: A systematic review

OBJECTIVE

The objective of this review is to assess the effect of total maxillary arch distalization (TMAD) treatment on the dental, skeletal, soft tissues, and airways during non-extraction camouflage treatment of class II division 1 patients.

METHODS

We performed a systematic review of the published data in four electronic databases up to April 2023. We considered studies for inclusion if they were examining the effects of TMAD during treatment of class II division 1 malocclusion in the permanent dentition. Study selection, data extraction, risk of bias assessment, and assessment of the strength of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool were performed in duplicate.

RESULTS

Out of the 27 articles that met the initial eligibility criteria, 19 studies were finally selected. Fair to relatively good quality evidence was identified after the risk of bias assessment of the included studies. Out of the 19 selected studies, 5 studies used inter-radicular TADs, 10 studies used modified C- palatal plate (MCPP), 3 studies used infra zygomatic crest (IZC) TADs, 1 study compared buccal TADs versus MCPP, and 1 study compared between cervical headgear and MCPP. The maximum amount of maxillary arch distalization using buccal TADs, MCPP, IZC TADs, and headgear was 4.2mm, 5.4mm, 5mm, and 2.5mm respectively. Different results regarding the amount of dental, skeletal, and soft tissue changes were observed.

CONCLUSIONS

The current low to very low certainty level of evidence suggests that TMAD is effective in camouflaging class II division 1 malocclusion. Future well-conducted and clearly reported randomized controlled trials that include a control group are needed to make robust recommendations regarding the effect of TMAD with different appliances on dental, skeletal, and soft tissue structures.

CLINICAL RELEVANCE

TMAD should be given priority with caution in class II patients who refuse the extraction of premolars. TMAD may be considered an adjunctive approach to solve cases associated with high anchorage need or anchorage loss.

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.

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.

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

OBJECTIVES

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

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.

Efficiency of maxillary total arch distalization using temporary anchorage devices (TADs) for treatment of Class II-malocclusions: A systematic review and meta-analysis

OBJECTIVES

To evaluate the treatment effects and post-treatment stability of the maxillary total arch distalization using TADs during the non-extraction treatment of class II malocclusions.

MATERIALS AND METHODS

Study involved an electronic search followed by hand searching for randomized and non-randomized clinical studies about maxillary total arch distalization using TADs. After data extraction and risk of bias assessment, meta-analysis was performed for dental, skeletal and soft tissue changes using the Generic-inverse variance approach by use of the mean difference and random-effect model.

RESULTS

In total, 1788 articles were identified, 88 full texts were screened and 22 studies were found eligible; 17 of them were included in the quantitative analysis. The means of distalization/distal tipping of the maxillary first molar were 4mm/3.17° in adults, 3.95mm/1.61° in adolescents after treatment with the Modified C-Palatal plate (MCPP), while they were 2.44mm/2.91° with the inter-radicular mini-screws. Both MCPP's treatment in adults and inter-radicular mini-screws resulted in significant intrusion of U6 (1.64 and 0.75mm, respectively), while insignificant extrusion of U6 was resulted in adolescents treated by MCPP. MCPP appliances resulted in palatal inclination/extrusion of maxillary incisors U1 (6.77°/2mm in adults, 7.46°/3.14mm in adolescents). In contrast, inter-radicular mini-screws resulted in less palatal less amount of palatal inclination/insignificant intrusion of U1 (2.42°/0.14mm). MCPP treatment also resulted in significant changes in the skeletal measurements (SNA, ANB, occlusal and mandibular planes). Insignificant differences were found between subgroups in the retraction amount of maxillary incisors, as well as the upper and lower lips. In the follow-up of adolescents treated with MCPP, a significant amount of mesial movement, mesial tipping, and extrusion (2.94mm, 2.84°, and 3.94mm, respectively) was found. However, skeletal and occlusal corrections of the Class II relationship were maintained.

CONCLUSIONS

Maxillary total arch distalization using TADs can be an effective and stable treatment procedure. However, RCTs or prospective cohort studies are highly recommended to establish a clinical evidence regarding their efficiency.

Long-Term CBCT Evaluation of Mandibular Third Molar Changes after Distalization in Adolescents

Introduction: This study aimed to evaluate mandibular molar changes after distalization using Class III elastics and modified C-palatal plates (MCPPs) in the maxilla and to use CBCT to specifically analyze the third-molar position after long-term retention in adolescents. Methods: The sample consisted of 65 mandibular third molars from 35 subjects, divided into two groups. Twenty-six of the third molars were from fourteen adolescent patients with Class I bimaxillary protrusion (mean age, 12.8 years) who had undergone bilateral maxillary distalization using an MCPP and mandibular distalization with Class III elastics with non-extraction treatment. For the control group, 39 third molars from 21 Class I normal-occlusion subjects were used. In the treated group, CBCT images were taken before distalization (T1), after molar distalization (T2), and at a long-term observation point (6.1 ± 2.7 years) (T3). Repeated measures ANOVA and a post hoc test with Bonferroni correction were used to analyze significant differences in the positions at the three points in time. Results: There were 2.3 and 1.7 mm of distal movement at the crown of the mandibular first and second molars, with distal tipping of 5.2° and 5.3°, respectively, and 3.0° of distal tipping of the third molars. Comparing the treated group with the control group at T3, there was a significant change in the angulation of the third molars (p < 0.001). In the long-term, the third molars from the treated group showed a downward and buccal position after distalization. Conclusions: In the long term, the developing mandibular third molar buds had downward and buccal positional changes after total arch distalization. These findings suggest the need for clinicians to consider the possibility of the impaction of developing third molars after mandibular total arch distalization in adolescents.