Palatal changes in crossbite patients treated with rapid maxillary expansion vs untreated ones: A geometric morphometric study

Evaluation of palate morphology in patients treated with leaf expander and hyrax expander: A geometric morphometric analysis

OBJECTIVE

The aim of this study was to evaluate changes in shape of the palatal vault after maxillary expansion with hyrax expander (HE) and leaf expander (LE), using 3D Geometric Morphometric Analysis.

SETTING AND SAMPLE POPULATION

Overall, 250 patients (110 M, 140 F) with maxillary transverse deficiency were selected for this study. In this study, 127 subjects were treated with HE, 123 with LE.

MATERIALS AND METHODS

Digital dental models were obtained pre-treatment (T0) and after 12 months from the cementation of the device (T1) and processed by means of a digital scanner. Linear and morphometric analyses were conducted to determine the effects of each appliance on dental measurements and palatal shape, and a multiple linear regression was performed to analyse the influence of anchorage and appliance type on final shape.

RESULTS

Morphometric analysis showed that there was a lowering of the palatal vault in the HE group, while in the LE group it remained unchanged: the difference in palatal shape at time T0 and T1 was statistically significant in both treatments (HE vs. LE). In the HE group, the change in shape also included the upper part of the palatal vault in the vertical dimension, while in the LE group the change in shape interested mainly palatal shelves and the lower portion of the palate.

CONCLUSIONS

Both LE and HE produce clinically significant changes in the morphology of the palatal vault.

Palatal Morphology After Treatment of Children With Obstructive Sleep Apnoea Using the Modified Twin-Block Appliance

OBJECTIVE

To investigate changes in the upper maxillary palates of children with obstructive sleep apnoea (OSA) and mandibular retraction who were treated using modified twin-block appliances (MTBAs).

METHODS

Thirty-five OSA children (age: 6-12 years) with mandibular retraction were included as the experimental group and 35 children who were Angle's class I but without mandibular retraction were included as the control group. The experimental group was treated with MTBA. Plaster models were made before the treatment and at the end of the 6-month treatment period. Plaster models of the control group were made at inclusion and after 6 months. Some plaster models were excluded because of damage or their failure to exhibit sufficiently clear marks, which left 26 pairs each for the experimental and control groups. The gender and age of the experimental group were matched with those of the control group at the end of the treatment. Three-dimensional (3D) digital model information was gathered using the external oral scanning model, and the data were extracted and analysed statistically to clarify the morphologic improvement in the maxillopalatine in OSA children treated using MTBAs.

RESULTS

After the OSA children with mandibular retraction were treated with MTBAs, the maxillary intercusp width, intermolar width, anterior palate width, posterior palate width, and surface area and volume of the maxillary palate significantly increased (*P < .05). By contrast, the anterior palatal height-apex level (H3) significantly decreased (*P < .05).

CONCLUSIONS

Compared with the control group, the narrow maxillary arch and basal bone were significantly enlarged after the OSA children with mandibular retraction were treated using MTBAs. The palatal surface area and volume increased, thereby allowing more space for accommodating the tongue and relieving transverse dissonance of the dentition.

Self-correction of posterior crossbite in childhood: a systematic review of long-term follow-up studies

BACKGROUND

The concept that posterior crossbite is not self-correcting has been controversial in the literature.

OBJECTIVE

To evaluate the incidence of self-correction of crossbite in different stages of dentition in childhood.

SEARCH METHODS AND SELECTION CRITERIA

A bibliographic search using the acronym PECOS was performed in five databases and in partial grey literature. Studies evaluating children with posterior crossbite in the deciduous or mixed dentition at initial examination and followed for at least 3 years were included.

DATA COLLECTION AND ANALYSIS

The data extraction of the studies included presents information on authorship, clinical characteristics, main results, and conclusions. The risk of bias in the studies was evaluated through the Joanna Briggs Institute tool. The certainty of the evidence was assessed using the GRADE tool.

RESULTS

Among the 3045 references identified, seven cohort studies met the eligibility criteria. The studies evaluated patients in transition from deciduous to mixed, mixed to permanent, and deciduous to mixed dentition. Two studies had a low risk of bias, three had a moderate risk, and two had a high risk of bias. The results showed posterior crossbite self-correction frequencies ranging from 12.2 to 77.1% during the transition from primary to mixed dentition, approximately 16% from mixed to permanent dentition, and a range from 20 to 82.8% from deciduous to permanent dentition. The level of certainty of the evidence generated ranged from very low to moderate.

LIMITATIONS

The observational design of the studies, without adequate control for confounding factors, and non-classification of the samples considering the types or the severity of the posterior crossbite.

CONCLUSION

The self-correction of posterior crossbite in childhood is possible. However, the results of this research do not allow to affirm how often the self-correction of posterior crossbite can occur. New studies that assess factors associated with the occurrence of self-correction of this malocclusion, including oral habits, may increase the certainty of the evidence.

REGISTRATION

PROSPERO CRD42022311935.

Long-term effects of orthodontic interceptive expansion treatment : A retrospective study

PURPOSE

The aim of this retrospective cohort study was to evaluate the long-term effects of interceptive orthodontic treatment with a removable expansion plate, based on transversal, sagittal, and vertical parameters.

METHODS

A total of 90 patients needing interceptive treatment due to a crossbite or space deficiency were included. Records consisting of clinical photos, radiographs, and digital dental casts were collected for evaluation at two time points: the start of interceptive treatment (T0) and the start of comprehensive treatment (T1). Molar occlusion, overjet, overbite, presence and type of crossbite, mandibular shift, and transversal measurements were recorded for comparison.

RESULTS

After expansion with removable appliances, a significant increase in intermolar width was achieved and could be maintained over the observation period (p < 0.001). However, no significant changes regarding overjet, overbite, or molar sagittal occlusion were observed. Crossbite correction was successful in 86.9% of patients with unilateral crossbite and in 75.0% of patients with bilateral crossbite (p < 0.001).

CONCLUSION

Early expansion with a removable expansion plate is a successful method to correct crossbites and increase intermolar width in the early mixed dentition phase. Results remain stable until the start of comprehensive treatment in the permanent dentition.

Measurement of the morphological data of primary teeth in northwest China

OBJECTIVE

This study aims to digitally obtain the morphological data of children's primary teeth in northwest China and evaluate the reliability of digitally obtaining the anatomical morphological data of primary teeth.

METHODS

A total of 308 extracted primary teeth and cone-beam computed tomography (CBCT) images of 407 primary teeth were collected in northwest China. Electronic digital Vernier callipers (accuracy: 0.01 mm) were used to measure the mesiodistal and buccolingual diameters and crown length of the extracted primary teeth and calculate the crown area and crown index. Each sample was scanned with an intraoral scanner (Trios2 3shape, Denmark), and the resulting stl format files were imported into Geomagic Wrap 2015 to measure the axial and buccolingual diameters and crown length. The crown area and crown index were then calculated. After verifying the accuracy of the CBCT image measurement, the CBCT image data of 407 samples were measured in SmartV software using the "measure length" function by referring to the coronal, sagittal, and horizontal planes to adjust the position of the reference line.

RESULTS

Northern Chinese have larger primary teeth than other populations (Japanese, white American, African, Icelander, Spanish, and Dominican Mestizo) but smaller primary teeth than native Australians. Compared to Indian primary teeth, northwest Chinese's primary teeth have larger diameters on the central axis and smaller diameters on the buccolingual surface. Male teeth are usually larger than female teeth. Compared with the results of Wang Huiyun's study, the axial and buccolingual diameters and crown length of all native tooth types in this total sample were significantly smaller at the 0.1% level, and only the axial diameters of the upper first molar and lower second molar and the crown length of the lower lateral incisor were significantly smaller at the 1% level. The results of the intraclass correlation coefficient of 308 extracted primary teeth expressed an excellent degree of agreement between the callipers and intraoral scanner for the following: mesiodistal diameter (0.956-0.991), buccolingual diameter (0.963-0.989), crown length [0.864-0.992, except for the upper canine (0.690)], crown index (0.850-0.975), and crown area (0.946-0.993).

CONCLUSION

The digital measurements of the intraoral scanner and CBCT image are in good agreement with the manual measurement of the Vernier calliper. The difference between the anatomical morphology size of the primary teeth measured in this study and the results of different populations could be due to different genetic backgrounds and environmental factors.

Digital (R)Evolution: Open-Source Softwares for Orthodontics

Among the innovations that have changed modern orthodontics, the introduction of new digital technologies in daily clinical practice has had a major impact, in particular the use of 3D models of dental arches. The possibility for direct 3D capture of arches using intraoral scanners has brought many clinicians closer to the digital world. The digital revolution of orthodontic practice requires both hardware components and dedicated software for the analysis of STL models and all other files generated by the digital workflow. However, there are some negative aspects, including the need for the clinician and technicians to learn how to use new software. In this context, we can distinguish two main software types: dedicated software (i.e., developed by orthodontic companies) and open-source software. Dedicated software tend to have a much more user-friendly interface, and be easier to use and more intuitive, due to being designed and developed for a non-expert user, but very high rental or purchase costs are an issue. Therefore, younger clinicians with more extensive digital skills have begun to look with increasing interest at open-source software. The aim of the present study was to present and discuss some of the best-known open-source software for analysis of 3D models and the creation of orthodontic devices: Blue Sky Plan, MeshMixer, ViewBox, and Blender.

Rapid Palatal Expansion Should Not Be Trivialized: Two Case Reports of Unexpected Complications

Rapid maxillary expansion is one of the most common orthodontic procedures performed in the pediatric population, easy to accomplish and compliance free, therefore really effective. Nevertheless, a careful diagnosis and frequent clinical follow-up appointments are necessary during the first weeks of active treatment. The purpose of this article was to report two cases of unexpected complications during orthopaedic maxillary expansion, involving two 7-year-old female patients, one presenting a saddle nose with suborbital hematoma and the other one an asymmetric palatal expansion. In both cases, the clinical situation progressively relapsed during the months following expansion appliance removal.