Clear Aligners in Pediatric Dentistry: A Short Review

Introduction

Oral diseases represent a highly relevant group of overall health-related conditions, affecting different age groups, gender, and socioeconomic classes. According to the World Health Organization (WHO), obtaining adequate oral health is the gateway to general health, well-being and overall quality of life.¹

Malocclusion, defined as inappropriate or abnormal teeth alignment, as well as problematic craniofacial relationship, constitutes a major oral health issue worldwide. Its prevalence ranges between 11% to 99%, and may be associated with multiple factors, including genetic and environmental components.¹ Dental caries, pulpal and periapical lesions, dental trauma, abnormality of development, oral habits and hereditary factors, which are common in children are all linked to malocclusion.²

Guidance of eruption and the development of primary, mixed, and permanent dentitions is an integral component of comprehensive oral health care in children. This type of guidance will help create permanent and future dental development which is safe, functional, and aesthetically pleasing. Early diagnosis and effective treatment of malocclusion can provide short and long term benefits while achieving occlusal relationship and function goals as well as dental aesthetics.³

Clear aligner treatment is an orthodontic procedure that aligns teeth using removable, comfortable, and invisible aligners. Clear aligners represent one of the most significant orthodontic innovations of the past decade. It is often used to treat various types of malocclusions, such as deep bite, open bite, crossbite, crowding, or Class II and III malocclusions.⁴

Aligners are the clear plastic alternatives for dental braces traditionally used for aligning the teeth. As aesthetics and comfort continue to improve, clear aligners are becoming the best alternatives for traditional fixed orthodontic appliances.⁵ The purpose of this article was to provide an overview of various applications of clear aligners in pediatric dentistry.

Materials Used in Clear Aligners

Thermoforming clear aligners use a variety of thermoplastic materials, including polyvinyl chloride, polyurethane, and polyethylene terephthalate glycol. Each aligner is thermoformed and final trimmed using 3D printing, stereolithography.⁵

Applications in Pediatric Dentistry

Correction of maxillary incisor position irregularities

da Silva VM et al. conducted a randomized clinical trial involving 32 patients aged 7 to 11 years for comparing the results and performance of clear aligners and 2 x 4 fixed braces in the treatment of irregularly positioned maxillary incisors in the mixed dentition. Digital models were made before treatment and after the appliance removal. Both the treatment options demonstrated comparable effectiveness in the treatment of crowding in the maxillary incisors.⁶

Eruption guidance

Eruption guidance makes a significant contribution in the development of permanent dentition, helping to form a harmonious, functional and esthetically acceptable occlusion. Clear aligners can serve as an alternative eruption guidance appliance for those who are reluctant about conventional orthodontic treatment. To facilitate the eruption of permanent teeth, certain amount of space is needed in the aligner. Tae and Jae in a 8 year 9 month old patient used a light curing, blue opaque block-out putty, Blue Blokker (Scheu - dental, Germany) to make room for eruption and regaining space.⁷

Maxillary expansion

Maxillary transverse defects are one of the most common craniofacial skeletal deformities. Palatal expansion has been performed for more than a century to correct the deformities, to widen the circumference of the dental arch, for changing the structure and function of the nasal cavity.⁸

Levrini et al. conducted a retrospective study involving 20 patients who underwent maxillary expansion using Invisalign clear aligners. Arch width, arch circumference, arch depth and molar inclination were measured on digital dental models before and after dental treatment. The results showed that overall arch width and arch circumference increased, while arch depth and molar inclination decreased.⁸

The Invisalign First System (First) is a new option designed specifically for patients in mixed dentition. It can be used on patients between the ages of 6 and 10 years with a crossbite, crowding, and a narrow maxillary arch in particular. Lanxin Lu et al. in their prospective cohort study evaluated the dental and dentoalveolar effects of First vs. acrylic splint rapid maxillary expander in the mixed dentition period. The author concluded that the Invisalign first system may be a suitable option in cases of mild to moderate maxillary transverse deficiency.⁹

Presurgical infant orthopaedics

Presurgical infant orthopaedics is the procedure used to manage patients with cleft lip palate anomaly which begins right after the birth. Aligner Nasoalveolar Molding Therapy was first published towards the end of 2019. These trays are digitally designed to bring the cleft segments together accurately. Each tray is designed to reduce the cleft gap in sequential appointments by 1 mm ensuring correct alignment of the cleft segments. Meanwhile, the nasal correction is performed using an acrylic elevator to bring nasal structures to the desired shape.¹⁰

Aligners in growing patients

Proper development of deciduous and mixed dentition is essential for maintaining oral health in growing patients.¹¹ Ravera S et al. evaluated the dento skeletal effects of the Invisalign mandibular advancement feature in skeletal class II growing patients aged 8 to 15 years with mandibular retrusion, at pre-pubertal and pubertal stages. Results showed that when used in the pre-pubertal stage of growth, Invisalign aligners with mandibular advancement feature induced mainly dentoalveolar effects in short-term and in the pubertal growth phase, the short-term effects of mandibular advancement feature involved dentoskeletal changes.¹²

Dianiskova et al. compared treatment outcomes using intermaxillary elastics in the correction of mild Angle’s Class II division 1 malocclusion with clear aligner verses fixed multibracket in patients aged 9 to 16 years. Class II elastics showed correction of sagittal discrepancy when combined with both clear aligner and fixed multibracket. Clear aligner allowed better control of inclination of the lower incisors.¹³

Advantages and Disadvantages

Patients tend to prefer clear aligner because of its superior comfort and esthetics. Clear aligners offer advantages of segmented movement of teeth and a shortened treatment duration.¹⁴ However its primary limitation is compliance. Invisalign are removable aligners that work well for patients, but not for doctors. Invisalign solves more malocclusion issues than braces.¹⁵

Conclusion

Based on the available evidence, clear aligner technology is effective in treating minor malocclusions. However, caution must be exercised while treating complex cases. Hence long term clinical studies are essential.

The main benefits of this technology are the comfort, aesthetics, shorter appointments and psychological advantage due to clear visible appearance. The success of treatment is highly dependent on the patient compliance and self-discipline. If the patient is cooperative, clear aligners might be a better choice than traditional methods.

However, further studies need to be conducted in pediatric population, and to explore its applications in preventive and interceptive orthodontics.

Conflict of Interest

Nil