Early treatment of anterior crossbite with eschler appliance: Two case reports

Anterior Crossbite (AC) originates from skeletal alterations, functional, dental or their association, and may have genetic and/or environmental infl uences. Its prevalence varies between 2.2% and 12% depending on age, ethnicity and the type of AC. During the primary dentition, it varies between 4% and 7%. The aim of this paper is to present two clinical cases of anterior crossbite correction in the primary dentition, in which the Eschler appliance was chosen for both treatments. Case Report Early treatment of anterior crossbite with eschler appliance: Two case reports Kamila de Oliveira Novais Machado1, Dauro Douglas Oliveira2 and Andre Wilson Machado3* 1DDS, Graduate program in Orthodontics, Pontifi cal Catholic University of Minas Gerais, Belo Horizonte, Brazil 2DDS, MS, PhD, Associate Professor and Program Director of Orthodontics, Pontifi cal Catholic University of Minas Gerais, Belo Horizonte, Brazil 3DDS, MS, PhD, Associate Professor, Section of Orthodontics, Dental School, Federal University of Bahia, Salvador, Bahia, Brazil Received: 08 July, 2020 Accepted: 13 July, 2020 Published: 15 July, 2020 *Corresponding author: Andre Wilson Machado, DDS, MS, PhD, Associate Professor, Section of Orthodontics, Dental School, Federal University of Bahia, Av. Araújo Pinho, 62 7 ° Andar – Canela, Salvador, Bahia, Brazil, Tel: +55 71 3336 6973; E-mail:


Introduction
Dentofacial disharmonies, especially in the sagittal plane, are of great interest among orthodontists, whereas the class III malocclusion occupies a prominent place. Clinically, in skeletal Class III malocclusions it is common to observe the presence of Anterior Crossbite (AC) in this type of malocclusion [1,2].
It is important to intercept this malocclusion at the earliest time possible because the anterior interlock due to the AC could interfere in the maxillary growth and dental development, which can aggravate the class III disharmony. In such cases early interception is mandatory and the objective if to help establish a favorable environment for the growth of the maxilla [3,4,[9][10][11][12][13][14][15]. However, one of the disadvantages of early interception is the diffi culty in predicting long-term stability, as the ideal time for intervention is still a controversial issue, especially when AC is of skeletal origin [16,17].
Several treatment modalities are used in the early interception of AC. Those vary between removable appliances associated with digital springs, fi xed or removable inclined planes, functional devices, face masks and fi xed orthodontic appliance [1,6,7,9,10,12,15,17,18]. However, there are few studies presenting the interception of this malocclusion in the primary dentition [7,10,17]. Due to the lack of clinical cases showing the correction of this malocclusion in the primary dentition and considering the importance of this correction at the earliest time possible, the publication of clinical cases is essential.
The aim of this paper is to present two clinical cases of anterior crossbite correction in the primary dentition, in which the Eschler appliance was chosen for both treatments.  Table 1).
Treatment objectives were (1) to correct anterior crossbite and (2) provide a normal environment for the growth of the maxilla.
The treatment was performed through a Eschler appliance [2,17], which promotes basically dental effects by means of

-Case n° 2
A 4 years and 6 months male patient sought orthodontic treatment because there was a perception by his parents that he had an anterior crossbite. The medical and dental history did not present relevant data and his oral hygiene and gingival condition were in normal standards. There weren't reports of previous orthodontic treatments. No parental characteristics of Class III malocclusion were observed or reported.
Facial evaluation showed a slightly concave profi le, no asymmetries and presence of passive lip seal. Patient presented in the primary dentition, coincident midlines, second molars' sagittal relationship in mesial step and presence of AC. In the evaluation of the CR-CO discrepancy, no functional deviation was observed ( Figure 5: pretreatment intraoral photographs).
In the panoramic examination, no relevant data was observed. Cephalometric analysis showed a Class I skeletal    pattern ( Figure 6: Pretreatment cephalometric radiograph and tracing; Table 2).
Like the previous case, the treatment aimed early interception of the anterior crossbite. The treatment was performed with the same appliance previously described and under the same recommendations (Figure 7: Intra-oral frontal view of the appliance).
Activation was initiated at the time of device's adjustment and activations of 1mm per month were performed for 5 months, totaling a period of 6 months. After this period, the patient had a normal anterior relationship and after achieving an appropriate overjet, activations were discontinued. In the retention phase, the same device was used for 7 months.
After one year of follow-up, improvement in facial profi le, smile and good stability of the case could be observed. However, no signifi cant cephalometric changes were found (Table 2)
In the cases described, it was decided to use an effective removable appliance called Eschler Appliance. At the end of treatment, favorable dental results, improvement in facial profi le and short-term stability were demonstrated [2,17,20].
Although very effective in correcting dental AC during primary dentition [21], the Eschler appliance is limited to correct AC due to unfavorable skeletal sagittal growth as demonstrated in the cases presented. follow up, it is associated with even more stable results [3,18].
Studies showed that, when comparing the AC correction with fi xed appliances, both present equally favorable stability and prognosis [3,4].
After one-year follow-up, new cephalometric evaluation was performed. In case 1, there was improvement in ANB and Wits. In case 2, in contrast, small improvements were found. Cephalometric measurements show the dentoalveolar compensatory potential of the treatment, in which the       upper incisors were moved buccally providing dentoalveolar remodeling [2]. However, because the corrections are only dentoalveolar, it makes the follow-up of patients who manifest AC in primary dentition indispensable in order to facilitate the second phase of treatment if necessary [2,10,11,16,22].
Another problem encountered in AC associated with Class III skeletal patients is the long-term stability. Although literature shows encouraging results with facemask therapy1,10, great relapse tendencies are also found which points out that a consistent retention phase is needed as well as longer periods of follow-up [14]. In the case presented the same appliance was used as retention for 6 -7 months. According to the literature a positive overjet and overbite at the end of treatment appears to maintain the anterior occlusion [23]. On the other hand, since Class III patients grow similar to untreated Class III patients after treatment, the patients needs to be kept under observation till the time they pass the third growth spurt at 18 years of age [14].
Pediatric dentists are commonly the fi rst professionals to be sought by parents for elucidation of AC in primary dentition. Proper diagnosis made by these professionals is essential due to the importance of early treatment, which goes beyond esthetic correction, prevents the worsening of the malocclusion, promotes a favorable environment for normal dentofacial growth and prevents the development of psychological problems and low self-esteem [2][3][4]9,[11][12][13][14]16,17,22,23]. Advantages such as reestablishing the position and normal activity of the perioral muscles, attenuation of the chances of developing temporomandibular disorders, correction of malocclusion-modifi ed chewing and speech and the creation of a favorable environment for permanent incisors eruption also strongly support early intervention of AC in primary dentition [3,4,7,10,17].
Lastly, to obtain favorable outcomes in early treatment of AC, it's essential to provide family guidance regarding the need and importance of patient and family adherence to the treatment. Also, the family should be warned about the uncertainty of long-term stability and the possibility of retreatments if unfavorable growth pattern occurs [1,16]. In such cases, when AC relapse occurs due to the unfavorable growth manifested by Class III malocclusion, the therapeutic approach of choice is to use the facial mask1,10 or skeletal anchorage [23].

Conclusion
The proper diagnosis associated with early treatment of anterior crossbite is decisive to achieve good occlusal and facial results, as well as reestablishing an appropriate psychological component for children. The use of the Eschler appliance represents a simple and effective option for the treatment of this condition while still in primary dentition.