Class III malocclusion and bilateral cross-bite in an adult patient treated with miniscrew-assisted rapid palatal expander and aligners

Pattern of microimplant displacement during maxillary skeletal expander treatment: A cone-beam computed tomography study

Objective

To analyze the microimplant (MI) displacement pattern on treatment with a maxillary skeletal expander (MSE) using cone-beam computed tomography (CBCT).

Methods

Thirty-nine participants (12 males and 27 females; mean age, 18.2 ± 4.2 years) were treated successfully with the MSE II appliance. Their pre- and post-expansion CBCT data were superimposed. The pre- and post-expansion anterior and posterior inter-MI angles, neck and apical inter-MI distance, plate angle, palatal bone thickness at the MI positions, and suture opening at the MI positions were measured and compared.

Results

The jackscrew plate was slightly bent in both anterior and posterior areas. There was no significant difference in the extent of suture opening between the anterior and posterior MIs (p > 0.05). The posterior MI to hemiplate line was greater than that anteriorly (p < 0.05). The apical distance between the posterior MIs was greater than that anteriorly (p < 0.05). The palatal thickness at the anterior MIs was significantly greater than that posteriorly (p > 0.01).

Conclusions

In the coronal plane, the angulation between the anterior MIs in relation to the jackscrew plate was greater than that between the posterior MIs owing to the differential palatal bone thickness.

Aligner hybrid orthodontic approach to treat severe transverse divergence in an adolescent girl: A case report

OBJECTIVE

To resolve a complex Class II case with unilateral crossbite through an aesthetic approach, namely a hybrid orthodontic treatment combining aligners with miniscrews and auxiliaries.

MATERIALS AND METHODS

A 14-year-old hypodivergent female patient with dental Class II and posterior crossbite presented for orthodontic treatment. The patient refused conventional fixed multibracket treatment and was therefore prescribed aligners used in association with miniscrews and sectional lingual appliances. Pre- and post-treatment records and 2-year follow-up records are presented.

RESULTS

Treatment objectives, namely ideal occlusion and improved profile, were achieved in 12 months. Post-treatment panoramic radiography showed good root parallelism, and no sign of either crestal bone height reduction or apical root resorption. The patient was satisfied with the functional and aesthetic outcomes, which were stable at 2 years.

CONCLUSION

This case report illustrates that a hybrid aligner approach may be used to treat posterior crossbite and class II malocclusion with reduced treatment times, optimal oral hygiene and excellent aesthetics.

Skeletal expansion using a miniscrew-assisted rapid palatal expansion in a 50-year-old patient

This case report illustrates a nonsurgical treatment plan using a miniscrew-assisted rapid palatal expander (MARPE) in a 50-year-old patient with maxillary transverse deficiency. The MARPE appliance consisted of a conventional Hyrax expander anchored to 4 orthodontic miniscrews. The exact locations of the miniscrews were determined with virtual planning software. Cone-beam computed tomography (CBCT) scans were superimposed on the maxillary digital model, and 3-dimensional-printed surgical guides were used to accurately position the mini-implants. A slow expansion protocol was used, and the appliance was held in place during the entire treatment (almost 20 months). Pretreatment, postexpansion, and posttreatment CBCT scans show the parallel expansion obtained without dental torque compensation or bite opening. The posttreatment scan showed that a long period is required to complete the midpalatal suture mineralization. MARPE has proven effective in correcting transverse discrepancies, even in adults. However, posttreatment CBCT imaging showed incomplete ossification of the midpalatal suture, demonstrating that the retention period should be extended in some adult patients.

Evaluation of bone depth, cortical bone, and mucosa thickness of palatal posterior supra-alveolar insertion site for miniscrew placement

BACKGROUND

The use of palatal miniscrew offers the possibility to improve the effectiveness of orthodontic expansion devices. Palatal expanders supported by miniscrew can be applied with different clinical protocols. Some authors proposed the use of four palatal miniscrews during miniscrew-supported palatal expansion to maximize skeletal effects in young adults' treatment. However, bone availability decreases in the posterior paramedian palatal regions, making the positioning of the two-posterior paramedian palatal miniscrews challenging, when it is performed avoiding nasal cavities invasion. Some authors proposed miniscrews insertion in a specific region located laterally to the palatal process of the maxillary bone, and apically relatively to the dento-alveolar process. The aim of this study was to evaluate the bone thickness, cortical bone thickness, and mucosae depth of this anatomical site that, in this study, was defined as palatal posterior supra-alveolar insertion site.

RESULTS

The evaluation of bone availability of palatal posterior supra-alveolar insertion site at different antero-posterior levels showed that the maximum amount of total bone thickness was found between the second premolar and the first molar. At this level total bone, thickness is significantly (p < .05) greater compared to the other sagittal sites and it offers on average around 2 mm of extra bone depth for miniscrew placement. Cortical bone thickness is adequate for primary miniscrew stability. Overall, cortical bone thickness considered at different insertion sites showed significant statistically (p < .05) differences. The findings of this study showed that palatal mucosa is particularly thick with average values ranging from 4 to 7 mm, and its extension ultimately affects miniscrew length selection. Palatal mucosa thickness showed no clinically significant differences comparing different sagittal and vertical insertion sites. Data also showed that palatal mucosal thickness slightly significantly increases (p < .05) with the inclination of the insertion axis relative to the occlusal plane. Finally, study findings showed that vertical growth pattern can significantly affect considered outcomes (p < .05).

CONCLUSIONS

Palatal posterior supra-alveolar insertion site is an appropriate site for posterior insertion of palatal miniscrews. Considering high anatomical variation preliminary CBCT evaluation is important to achieve optimal miniscrew placement.

Performance of Rigid and Soft Transfer Templates Using Viscous and Fluid Resin-Based Composites in the Attachment Bonding Process of Clear Aligners

Objectives

The study aims at assessing the accuracy of the process of attachment bonding in aligner treatments. The analysis leads to the error estimation in the faithful reproduction of master model attachments using two types of transfer templates and two light-curing resin-based composites usually used in orthodontics.

Methods

The authors have used two transfer templates made of two different materials. The first, named Leone-biocompatible thermoforming material hard/soft, has a lower Young's modulus and is labelled as soft, while the other, named Leone-biocompatible thermoforming material, is marked as rigid. The resin-based composites possess different mechanical and rheological properties. Specifically, Transbond™ XT Light Cure Paste Adhesive, 3M has a higher viscosity than the TetricEvoflow, Ivoclar Vivadent, a flowable nanohybrid composite. The authors attempt to estimate the performance ranking between the four possible couples obtained by combining the two light-curing resin-based composites and transfer templates. Each combination was repeated in six models and compared with twelve master models, resulting in 36 total samples. A 3-D laser scanner is used to generate a digital model of each model. The comparison between digital models is the base for a comparative assessment in terms of relative and absolute error. The relative error is estimated using scalar performance indicators ranging from 0 to 1, where 1 indicates the optimum matching. The absolute error estimated from the mean square error between the coordinates of each digital model yields the reproduction accuracy in micrometer. Furthermore, the authors attempted to assess the error distribution by evaluating the point-by-point difference between the digital models.

Results

This analysis aims at localizing the sources of error in the considered models. The use of Transbond™ XT Light Cure Paste Adhesive, 3M with a rigid transfer template is always associated with significant accuracy and minor dispersion. However, in a few instances, using the soft template or the flowable resin-based composite can lead to bad performances. Significance. The data processing bestowed the following performance ranking from the first with lower reproduction error to the last characterized by the worst performance: (1) attachments bonding with rigid template and Transbond™ XT Light Cure Paste Adhesive, 3M, (2) attachments bonding with soft template and Transbond™ XT Light Cure Paste Adhesive, 3M, (3) attachments bonding with rigid template and TetricEvoflow, Ivoclar Vivadent, and (4) attachments bonding with soft template and TetricEvoflow, Ivoclar Vivadent.

Success and complication rate of miniscrew assisted non-surgical palatal expansion in adults - a consecutive study using a novel force-controlled polycyclic activation protocol

Introduction

Bone-borne miniscrew assisted palatal expansion (MAPE) is a common technique to improve maxillary transverse deficiency in young adolescents. Adult patients usually present a challenge, as they often require additional surgical assisted maxillary expansion (SARPE). There is still no clear statement about non-surgical expansion in adult patients using this technique. The aim of this study was to evaluate the success and complication rate of non-surgical palatal expansion in adults utilizing MAPE with a novel force-controlled polycyclic expansion protocol (FCPC).

Methods

This consecutive study consisted of 33 adult patients with an average age of 29.1 ± 10.2 years (min. 18 years, max. 58 years), including one dropout patient. First, four miniscrews were inserted and after 12-weeks latency, the expander was placed and the FCPC protocol was applied (MAPE group). In case of missing expansion, a SARPE was performed (SARPE group). After maximum expansion, a cone beam CT was made and widening of the midpalatal suture was measured. The outcome variables were successful non-surgical expansion and, with sample size power above 80%, the odds of failed non-surgical expansion and associated complications were evaluated. The primary predictor variable was age. Statistical analysis was performed using R (Version 3.1) to calculate power, to construct various models for measuring the odds of requiring surgical intervention/complications, and others.

Results

Successful non-surgical expansion was achieved in 27 patients (84.4%), ranging from 18 to 49 years. Mean age differed significantly between both groups (26.8 ± 8.2 years vs. 41.3 ± 9.9 years; p < 0.001). Mean expansion at the anterior and posterior palate for the MAPE group was 5.4 ± 1.5 mm and 2.5 ± 1.1 mm, respectively. Among these subjects’ complications were observed in 18.5%. Age significantly increased the odds of complications (p = 0.019).

Conclusions

1. The success rate of MAPE among individuals aged 18 to 49 years was 84.4%.

2. A V-shaped expansion pattern in the antero-posterior dimension was mostly observed.

3. Complications were significantly associated with age.

4. A careful expansion protocol seems to be beneficial to prevent unfavorable results in adult patients.

Trial registration

Consecutive cohort study, Review Board No. EK-2-2014/0016.

Severe transverse discrepancy in adult Class III patient: Parallel rapid palatal expansion with a bone-borne tandem expansion screws (TSE) followed by lingual fixed appliance for a non-surgical treatment: A case report

INTRODUCTION

Midpalatal suture opening in young adults is often difficult to achieve, depending on the suture maturation stage. It has been suggested that it is possible to avoid surgery and still achieve a successful pure skeletal expansion if a bone-borne Miniscrew-Assisted Rapid Palatal Expander is chosen (MARPE).

CASE PRESENTATION

The following case report describes the use of a pure bone-borne miniscrew-assisted rapid palatal expander followed by lingual fixed appliance to correct a severe transversal discrepancy in an adult patient characterized by a hyperdivergent mandibular skeletal pattern.

MANAGEMENT AND OUTCOMES

All treatment phases were digitally planned, starting with the miniscrews' insertion with a three-dimensionally printed surgical guided (Miniscrew Assisted Palatal Application: MAPA system) and Tandem Skeletal Expander (TSE) appliance, to the lingual indirect bonding. The final outcomes confirmed that this orthodontic approach represented a valid alternative to orthognathic surgery, with a significant improvement of the patient's occlusion and facial appearance.

DISCUSSION

The Tandem Skeletal Expander (TSE) design and the expansion protocol applied allowed to obtain a significant and stable skeletal increase of transversal diameters by digital planning of the insertion of miniscrews, with lower risks and costs than other surgical approaches.

Association of the mid-palatal suture morphology to the age and to its density: A CBCT retrospective comparative observational study

OBJECTIVE

The twofold aim of the present investigation was to: 1. evaluate the degree of mid-palatal suture (MPS) maturation via CBCT in relation to patient age, and 2. to determine whether there was a correlation between quantitative (i.e., suture density) and qualitative (i.e., suture morphology) analysis.

MATERIALS AND METHODS

The stage of mid-palatal suture maturation and suture density ratio were assessed for 160 subjects on CBCTs using five qualitative stages proposed by Angelieri with the addition of three additional stages (i.e., B/C, C/D and D/E) and quantitative grey density scores of Grünheid MPS1,2,3,4 with the addition of parasutural bone and soft palate. The repeatability of both methods was evaluated using Cohen's K.The relationship between midpalatal suture maturation and age was assessed using ANOVA and Classification and Regression Trees (CART) analysis and tabulation and a χ² test for quantitative and qualitative analysis respectively. Statistical significance was assessed using a 5% threshold.

RESULTS

The final sample included 160 CBCTs (80 male,80 female; mean age 23.2±13.5). Both methods were found to be correlated and highly repeatable. In addiction they showed an age-related correlation in MPS morphology.

CONCLUSION

The mid-palatal suture density ratio and the stage of mid-palatal suture maturation has the potential to become useful in clinical practice. In fact, despite the correlation between MPS maturation stage and age, the latter parameter cannot be used as a clinical discriminator due to the great variability between subjects. It is therefore advisable to assess each patient individually on CBCT scans in order to determine treatment choices.

Clear Aligners: Between Evolution and Efficiency-A Scoping Review

In recent years, clear aligners have diversified and evolved in their primary characteristics (material, gingival margin design, attachments, divots, auxiliaries), increasing their indications and efficiency. We overviewed the brands of aligners used in Italy and reviewed the literature on the evolution of clear aligners based on their characteristics mentioned above by consulting the main scientific databases (PubMed, Scopus, Lilacs, Google Scholar, Cochrane Library). Inclusion and exclusion criteria were established. The data were collected on a purpose-made data collection form and analyzed descriptively. From the initial 580 records, 527 were excluded because they were not related to the subject of the review or because they did not meet the eligibility criteria. The remaining 31 studies were deemed comprehensive for the purpose of the review, although the “gingival margin design” feature and “auxiliaries” tool are not well represented in the more recent literature. Current knowledge on invisible aligners allows us to have a much clearer idea of the basic characteristics of aligner systems. There remains a need to deepen the use of systems other than Invisalign™ to give greater evidence to aligners that are very different based on the characteristics analyzed here and that are very widespread on the market.

Class II subdivision with skeletal transverse maxillary deficit treated by single-sitting bone-borne appliance

This case report describes orthodontic treatment including both skeletal maxillary expansion and unilateral distalization by means of a single bone-borne appliance followed by clear aligner therapy in a young adult patient. A surgical guide was digitally designed and three-dimensionally printed to facilitate the placement of four miniscrews in the palatal vault. The miniscrews were fitted and the bone-borne appliance was delivered in a single clinical appointment. The postexpansion photographic records and models demonstrate the opening of the palatal median suture, the pure skeletal expansion, and the resolution of the left crossbite after 40 activations. Specifically, left molar Class I was obtained in about 5 months without any loss of anterior anchorage, and the subsequent aligner phase achieved all of the objectives established in the treatment plan. This case report shows clearly how careful digital planning of miniscrew insertion and the delivery of a pure bone-borne appliance in a single sitting enabled good clinical outcomes to be achieved in an acceptable timeframe, without side effects, even in a young adult patient.

Assessment of stiffness and load deflection of orthodontic miniscrews used for palatal anchorage: An in vitro biomechanical study

OBJECTIVE

The purpose of this study was to evaluate the biomechanical properties of miniscrews of 5 different lengths, 2 different diameters, and different combinations of insertion used for palatal skeletal anchorage.

MATERIALS AND METHODS

Twenty-four different combinations of a total of 120 miniscrews of two different diameters (2.0mm and 2.3mm) and five different lengths (9mm, 11mm, 13mm and 15mm) were tested at different angles of insertion (90° and 45°) and distances from a synthetic bone block (3mm, 5mm, 7mm). Samples were fixed in an Instron Universal Testing Machine and a load was applied in single cantilever mode to the neck of each miniscrew. The stiffness and maximum load before permanent deformation were recorded. Model-based recursive partitioning testing (CART) was used to evaluate differences between groups.

RESULTS

Significantly higher forces were necessary to deform miniscrews of diameter 2.3mm than those of 2.0mm, those inserted at an angle of 45° with respect to 90°, and at smaller distances between the miniscrew neck and block; in addition, the maximum load and stiffness increased with increasing screw length.

CONCLUSION

This in vitro experimental study showed strong correlations between deformation load and miniscrew geometry, insertion angle and distance from the synthetic block, results that should be considered when planning miniscrew insertion in order to reduce the risk of unwanted fracture.

Differential assessment of skeletal, alveolar, and dental components induced by microimplant-supported midfacial skeletal expander (MSE), utilizing novel angular measurements from the fulcrum

Background

In order to assess skeletal expansion, alveolar bone bending, and dental tipping after maxillary expansion, linear and angular measurements have been performed utilizing different craniofacial references. Since the expansion with midfacial skeletal expander (MSE) is archial in nature, the aim of this paper is to quantify the differential components of MSE expansion by calculating the fulcrum locations and applying a novel angular measurement system.

Methods

Thirty-nine subjects with a mean age of 18.2 ± 4.2 years were treated with MSE. Pre- and post-expansion CBCT records were superimposed and compared. The rotational fulcrum of the zygomaticomaxillary complex was identified by localizing the interfrontal distance and modified interfrontal distance. Based on the fulcrum, a novel angular measurement method is presented and compared with a conventional linear method to assess changes of the zygomaticomaxillary complex, dentoalveolar bone, and maxillary first molars.

Results

From 39 patients, 20 subjects have the rotational fulcrum of the zygomaticomaxillary complex at the most distant points of the interfrontal distance (101.6 ± 4.7 mm) and 19 subjects at the most distant points of the modified interfrontal distance (98.9 ± 5.7 mm). Linear measurements accounted for 60.16% and 56.83% of skeletal expansion, 16.15% and 16.55% of alveolar bone bending, and 23.69% and 26.62% of dental tipping for right and left side. Angular measurements showed 96.58% and 95.44% of skeletal expansion, 0.34% and 0.33% alveolar bone bending, and 3.08% and 4.23% of dental tipping for the right and left sides. The frontozygomatic, frontoalveolar, and frontodental angles were not significant different (P > 0.05).

Conclusions

In the coronal plane, the center of rotation for the zygomaticomaxillary complex was located at the most external and inferior point of the zygomatic process of the frontal bone or slightly above and parallel to the interfrontal distance. Due to the rotational displacement of the zygomaticomaxillary complex, angular measurements should be a preferred method for assessing the expansion effects, instead of the traditional linear measurement method.

Assessment of respiratory muscle strength and airflow before and after microimplant-assisted rapid palatal expansion

OBJECTIVES

To assess alterations in respiratory muscle strength and inspiratory and expiratory peak flow, as well as skeletal and dental changes in patients diagnosed with transverse maxillary deficiency before and after microimplant-assisted rapid maxillary expansion (MARPE).

MATERIALS AND METHODS

Twenty patients (13 female and 7 male) were assessed by respiratory tests in three different periods: T0 initial, T1 immediately after expansion, and T2 after 5 months. Tests included: maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), oral expiratory peak flow, and inspiratory nasal flow. Cone-beam computed tomography measurements were performed in the maxillary arch, nasal cavity, and airway before and immediately after expansion.

RESULTS

There was a significant increase in MIP between T0 and T2 and MEP between T0 and T1 (P<.05). Oral and nasal peak flow increased immediately after and 5 months later, especially in patients with initial signs of airway obstruction (P<.05). In addition, after expansion there was a significant enlargement of the nasal cavity, alveolar bone, and interdental widths at the premolar and molar region. Molars tipped buccally (P<.05) but no difference was found in premolar inclination. MARPE increased airway volume significantly.

CONCLUSIONS

Skeletal changes promoted by MARPE directly affected airway volume, resulting in a significant improvement in muscle strength and nasal and oral peak flow.