Dental Management of a Child Patient with Amelogenesis Imperfecta

INTRODUCTION

Amelogenesis imperfecta (AI) is a genetically and clinically heterogeneous group of inherited disorders that occurs as a result of defective ameloblasts affecting the enamel matrix formation and enamel mineralization process. In AI, the structure and clinical appearance of both primary and permanent dentition are affected.¹

According to Witkop classification, the main phenotypes of AI are based on enamel defects and the subtypes are based on clinical appearance and mode of inheritance. The four main phenotypes are hypoplastic, hypomaturation, hypocalcified, and hypomaturation-hypoplastic type with taurodontism.²

The mildest problems are found in the hypoplastic type associated with thin enamel, spacing in-between teeth, pits and grooves on the surface, delayed eruption, and 50% of cases have an anterior open bite. Hypomaturation type is associated with mottled, opaque, or red-brown discolored enamel. The most severe problems are linked with hypocalcified type with normal thickness of enamel which is softer than normal, resulting in enamel being easily chipped off, large masses of supragingival calculus, and unerupted teeth. In the hypomaturation-hypoplastic type with taurodontism, the enamel is characterized by pitting and mottling on the surfaces together with large pulp chambers, elongated crowns, and apically positioned bifurcations.^3,4

The following report presents a patient with AI, where his appearance and function of the teeth led to diminished social interactions. Provisional treatment was performed to improve dental esthetics, preserve oral function, and improve the patient’s self-confidence.

CASE DESCRIPTION

A 9-year-old boy presented to the Division of Pediatric Dentistry requesting treatment for his extremely poor dental esthetics with severe discoloration and severe sensitivity. His dental condition had made him ashamed of smiling leading to a negative relationship with peers. There was no family history, and medical history was non-contributory.

The extraoral examination did not reveal any relevant findings. Intraoral examination revealed, generalized gingival inflammation. The enamel appeared soft, opaque, and yellow-white upon eruption. It tended to chip off easily and there was only a very thin layer of enamel at the gingival margins, exposing large areas of underlying highly sensitive brown dentine (Fig. 1). Rough broken occlusal surfaces were found on all posterior teeth with marked attrition and caries. Therefore, clinical crown height was reduced. Also, 84 was mobile. Hypersensitivity was present. Dental panoramic tomography (DPT) (Fig. 2) revealed that it was difficult to distinguish enamel and dentine.

For the definitive diagnosis, a radiographic analysis was carried out and a hematoxylin and eosin stained decalcified section and a ground section of a deciduous tooth (54) were histopathologically investigated (Fig. 3) and pedigree plotting was used. Then, it was diagnosed as (AI) with a hypocalcified type of sporadic inheritance.

Due to the complexity of the condition, a multidisciplinary approach in treatment planning was needed to ensure optimal long-term results. Accordingly, written informed consent was taken from the parents and patient for the planned treatment. Treatment was done to prevent symptoms, further complications, and to improve esthetics up to the level acceptable to the child.

Following a 3-day diet chart analysis, a dietary modification was done. The patient’s brushing technique was modified into a modified “Bass” technique. Full mouth scaling was done.

The dentinal caries was stabilized with glass–ionomer cement (GIC). Application of 2.26% sodium fluoride varnish was also performed in the same visit and it was continued after 3 months. A fluoride mouth wash (0.05% NaF) was also prescribed to use daily.

Orthodontic separators were placed in-between 36, 75 and 46, 85 to create space for placement of stainless steel crowns (SSCs) without interproximal reduction. Stainless steel crowns on all the deciduous molars and permanent molars were cemented using type I, luting GIC except on 54 since more than two-thirds of the roots of 54 had resorbed. Because of this occlusal vertical dimension (OVD) was further increased and the overbite was reduced. Composite veneering on all anterior teeth was done.

The newly erupted teeth were severely hypomineralized and hypersensitive. Hence, composite veneering was done one after the other, after the eruption of permanent premolar teeth (Figs 4 and 5).

After the restorative procedure, the patient’s hypersensitivity completely disappeared and he was happy with the newly established function. Finally, it was observed that there was a drastic change in appearance as well as the behavior of the child (Fig. 6). Dental panoramic tomography showed the gradual development of the occlusion by exfoliation of the deciduous teeth and eruption of permanent teeth (Fig. 7).

DISCUSSION

Full mouth rehabilitation with a multidisciplinary approach is needed to improve the quality of life of individuals with AI.⁵ Due to the presence of mixed dentition as in this child, definitive treatment options often have to be delayed until permanent dentition is completed, requiring careful treatment coordination and proper sequencing between different dental disciplines starting at a young age.⁶ Preserving as much tooth structure as possible is highly desirable as restorations will need to be replaced several times during adulthood. The age of the patient, socioeconomic status, and severity of the disorder should be considered while planning treatment.

To achieve a successful outcome, a stepwise approach in treatment planning is required starting with the most conservative but esthetically acceptable treatment. Management includes an initial phase which is undertaken during the primary and mixed dentition, transitional phase; when all permanent teeth have erupted and continued till adulthood culminating with the definitive phase; in adulthood.⁷ The presented patient was managed under the category of mixed dentition stage.

Professional support with oral hygiene instructions, flossing, scaling and polishing, fluoride supplements, and detection of carries is important. Furthermore, regular use of desensitizing agents, and application of casein phosphopeptide amorphous calcium phosphate (CPP-ACP) may reduce sensitivity, prevent caries, and enhance remineralization.⁵ Suitable preventive measures were applied in the management of this patient to successfully control gingivitis, caries, and tooth wear.

The bond strength of resin to enamel is decreased due to higher protein content in affected enamel.⁵ In patients with hypoplastic types of Al, there is sufficient enamel available for bonding composite resins. However, the hypocalcified variety of Al, the enamel is usually insufficient for direct bonding. Despite this, with the continuous development of dentine-bonding systems, at present composite restorations could be successfully and predictably used in patients with AI.⁵

Anterior porcelain veneers and porcelain jacket crowns are also useful, particularly if sufficient enamel is available for bonding. However, an obvious disadvantage is an irreversible damage to the already compromised and worn teeth. Their use in young patients usually is contraindicated due to the presence of large pulps which may affect the vitality of the pulp and changes in the cervical margins of anterior teeth.^4,5,7 Composite veneers of permanent incisors improve esthetics, reduced sensitivity. In addition, composites are a cost-effective, noninvasive restorative material of choice for all patients with AI. This patient was also treated with composite resin and with preformed SSCs considering minimum intervention restoration, immature pulp, and immature gingivae.

The esthetics of premolars is often not a concern and when wear and sensitivity are an issue, full coronal coverage can be provided with indirect or direct composite onlays. Canines are more likely to be an esthetic concern in addition to sensitivity and wear. Therefore, composite can be used to address these problems. The key to restorative success in the esthetic zone depends mainly on the combination of gingival and dental factors. Definitive treatment cannot be performed until full dental and gingival maturity is gained. Therefore, it is the responsibility of the dental surgeon who manages the child’s dental care to maintain the dentition until adulthood.⁸

The fully erupted permanent molars affected by AI may require to be protected with gold onlays, full crowns of cobalt-chromium, or SSCs. Gold restorations will be more definitive and the margins can be kept supragingivally to aid gingival health.⁹

Loss of OVD leads to a poor facial profile.⁵ Prevention of reduction in OVD is best as early as possible, preferably in the primary dentition by preformed posterior SSCs.¹⁰ Since, this patient had an increased overbite, reduced lower facial height, and grossly broken down posterior teeth, cementation of SSCs on 16, 26, 36, 46, 55, 64, 65, 74, 75, 84, and 85 were done. Stainless steel crowns were selected since it is low cost and to protect the immature and large pulp from exposure which can occur with extensive crown preparations for porcelain fused to metal crowns. In tooth preparation for SSC, a conservative technique of tooth separation using orthodontic separators before the insertion of the crowns is recommended.¹¹ This technique was applied in this patient to prevent a proximal reduction of tooth structure which allows the SSC to be inserted without tooth reduction. Furthermore, GICs are likely to be better luting agents for the crowns compared with zinc phosphate, especially if there are large areas of exposed dentin. Following the exfoliation of the deciduous molars, composite veneering of permanent premolars was done, to protect them from caries, tooth wear, and sensitivity. Impacted 42 may need surgical removal and maintain 82 as long as possible as, it is not indicated to fix traction as there are high chances to detach the bracket due to poor quality enamel.

CONCLUSION

Preventive and restorative care had to be taken into full consideration as the social and psychological development of the child will be affected if AI is not treated during their early years. A successful outcome of this treatment was mainly due to an early diagnosis of this child’s emotional aspect and adopting concurrent multidisciplinary treatment procedures.

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