Full-Mouth Reconstruction in Amelogenesis Imperfecta: A Case Report

Introduction

The term “amelogenesis imperfect” refers to a group of inherited enamel diseases that are clinically and genetically diverse, characterized by abnormalities in the structure, thickness, and composition of enamel [1]. Enamel, the hardest tissue in the human body, is composed primarily of hydroxyapatite crystals, with only a small amount of mature protein [2–4]. Disruptions in amelogenesis lead to enamel anomalies, which in turn generate the various phenotypes observed in amelogenesis imperfecta patients [5–7].

Amelogenesis imperfecta negatively affects a wide group of individuals, with an incidence estimated between 1 in 700 and 1 in 14 000 live births. Although uncommon, it can result in multiple clinical issues, including rough occlusal surfaces, enamel deterioration, pitting in the enamel, increased tooth sensitivity, and aesthetic concerns. Beyond these physical difficulties, patients frequently experience emotional strain, which negatively impacts mental health and self-confidence. Thus, this condition influences not only dental health but also emotional well-being and social relationships [1,8,9].

Several crucial genetic factors are implicated in amelogenesis imperfecta. Mutations have been identified in key genes, such as AMELX, which encodes an enamel matrix protein essential for tooth formation; ENAM, which encodes an essential enamel-formation protein; MMP20, which is crucial for breaking down enamel matrix proteins; and KLK4, which is vital for enamel maturation during tooth development. Understanding these genetic factors is essential for tailoring treatment and improving patient outcomes [10]. Amelogenesis imperfecta can be inherited in X-linked, autosomal dominant, or autosomal recessive patterns, with phenotypic variations often observed even within the same family [11].

The most widely used classification system, developed by Witkop [8], categorizes amelogenesis imperfecta into 4 main types: hypoplastic amelogenesis imperfecta, marked by reduced enamel thickness; hypomaturation amelogenesis imperfecta, in which enamel of normal thickness appears mottled, opaque, and brittle; hypocalcified amelogenesis imperfecta, featuring normal thickness but poor mineralization and softness; and hypomaturation–hypoplastic amelogenesis imperfecta with taurodontism, which combines these features.

Nusier expanded Witkop’s classification of amelogenesis imperfecta by integrating clinical, radiological, and genetic data, thereby improving diagnostic accuracy. Clinically, diagnosis requires a detailed family history and comprehensive examination. Radiographically, differences in enamel density are seen. In hypoplastic amelogenesis imperfecta, enamel is thin and detached from dentin, while in hypocalcified amelogenesis imperfecta, enamel resembles that of dentin. Genetic testing, although not standardized, can confirm mutations [12]. Differential diagnoses include dentinogenesis imperfecta, dental fluorosis, and environmentally induced enamel hypoplasia [6,13].

Effective management of amelogenesis imperfecta requires a multidisciplinary approach involving pediatric dentistry, periodontics, orthodontics, prosthodontics, and, at times, oral surgery. Primary goals include preserving existing tooth structure, restoring aesthetics and function, re-establishing the appropriate occlusal vertical dimension, and improving quality of life [9,14,15].

Treatment is typically custom-made to the patient’s age and development: preventive and adhesive techniques in childhood, and comprehensive full-mouth rehabilitation with crowns, veneers, or fixed partial dentures (FPDs) in adulthood [16]. Most of the reported literature shows amelogenesis imperfecta management performed with different materials. Still, very few demonstrate the use of a combined material approach to achieve occlusal stability while providing excellent aesthetic outcomes [14–17]. This report presents the case of a young woman diagnosed with hypoplastic amelogenesis imperfecta. The treatment methodology is analyzed through the lens of evidence-based methods, citing relevant literature [17] and emphasizing interdisciplinary treatment protocols. Employment of a unique hybrid material combination in the full-mouth reconstruction to improve posterior strength and anterior aesthetics is not commonly described in the amelogenesis imperfecta literature. Moreover, compared with previous studies, this case integrates digital technology into occlusal analysis and management and employs a phased surgical intervention, representing a modernized treatment approach.

Case Report

CLINICAL MANAGEMENT:

Treatment planning followed an interdisciplinary approach and aimed for full-mouth rehabilitation using single crowns and FPDs. Phase I (initial treatment) included oral prophylaxis (Cavitron® Select SPS, Dentsply Sirona, Charlotte, NC, USA), scaling and root planning, adherence to the Caries Management by Risk Assessment protocol (CAMBRA), and oral hygiene instructions. Diagnostic casts were fabricated using irreversible hydrocolloid (Tropicalgin, Zhermack Italy) and mounted on a semi-adjustable Artex^® articulator (Amann Girrbach GmbH, Koblach, Austria) using a facebow transfer. Centric relation records were captured with an anterior jig fabricated from autopolymerizing resin (Unifast Trad™, GC Corporation, Tokyo, Japan).

Evaluation of the vertical dimension of occlusion (OVD) revealed reduced space due to tooth structure loss and a shortened lower facial third. A diagnostic wax up followed by a mock-up demonstrated the need for a 4-pin OVD increase (Figure 2). Subsequently, caries removal procedures were performed, and the teeth were restored with composite resin restoration (Nanocomposite; Filtek™ Z350 XT Universal Restorative, 3M ESPE, St. Paul, MN, USA). Teeth were prepared for full-coverage restorations afterward, using preparation guides made from putty/wash addition silicone impression material (Express™ 2 Putty, 3M ESPE, Seefeld, Germany). Provisional restorations were fabricated to restore the reduced OVD. These full-contour computer-aided design/computer-aided manufacturing (CAD/CAM) acrylic provisional restorations (Telio® CAD, Ivoclar Vivadent AG, Schaan, Liechtenstein) were tested for 4 months to evaluate aesthetics, phonetics, and functionality, and to serve as a guide for crown-lengthening procedures. Appropriate modifications were made as needed to confirm the patient’s tolerance of the increased OVD. These provisions were replaced twice to ensure durability and minimize OVD loss from surface wear.

Phase II (surgical interventions) included the extraction of impacted third molars and retained deciduous tooth #A, along with crown lengthening on teeth #2–5, 12–15, 18, 20, 21, and 28–31 (Figure 3). Phase III (definitive restorative treatment) involved delivery of porcelain-fused-to-metal (PFM) crowns using a high noble gold–platinum alloy (Degunorm®, DeguDent GmbH, Hanau, Germany) veneered with porcelain (Vita VMK Master®, VITA Zahnfabrik, Bad Säckingen, Germany) and FPDs on posterior teeth, as well as lithium disilicate crowns (IPS E. max, Ivoclar Vivadent, Schaan, Liechtenstein) and FPDs on anterior teeth and premolars. Final impressions were obtained using polyether (Impregum™ Penta™, 3M ESPE, Seefeld, Germany), and interocclusal records were obtained while provisional restorations maintained stable occlusion. Metal frameworks were tested, and the fit was confirmed using a silicone-based fit-checking material (Fit Checker™ Advanced, GC Corporation, Tokyo, Japan). Porcelain bisque try-ins for both PFM and lithium disilicate units followed. Final cementation employed resin-modified glass ionomer cement (Fuji CEM® Automix, GC Corporation, Tokyo, Japan) for PFM crowns and FPDs and resin cement (RelyX™ Ultimate, 3M ESPE, Seefeld, Germany) for lithium disilicate crowns and FPDs.

Phase IV (maintenance) included topical fluoride gel (Fluor Protector Gel®, Ivoclar Vivadent AG, Schaan, Liechtenstein) and chlorhexidine mouth rinse (Corsodyl® 0.2%, GlaxoSmithKline, Brentford, UK) (Figure 4). A maxillary occlusal guard (NTI-TSS®, American Dental Systems, St. Paul, MN, USA) was constructed for the patient, and periodontal and prosthodontic follow-ups were recommended every 3 months (Figure 5).

Treatment resulted in markedly improved smile esthetics, enhanced harmony, and a more natural appearance. Functionally, anterior guidance and posterior support were restored, correcting deficiencies in the production of “F” and “S” sounds. Periodontal health was preserved through diligent oral hygiene practices. The patient reported significant satisfaction and enhanced self-confidence after completing the treatment. Long-term prognosis is favorable, contingent on compliance with oral care and regular follow-up. The patient attended the 1-month follow-up and demonstrated excellent adherence to good oral hygiene practices. However, the patient did not attend later follow-up visits despite multiple attempts to contact her.

Discussion

Amelogenesis imperfecta affects both primary and permanent dentition. Affected teeth may appear yellow, brown, or gray, with pitting, size reduction, or rough surfaces. Hypoplastic amelogenesis imperfecta is characterized by thin enamel, while hypocalcified amelogenesis imperfecta exhibits soft and fragile enamel. Hypomaturation amelogenesis imperfecta presents with mottled, opaque enamel that is prone to cracking [18]. Clinical manifestations include delayed dental eruption, impaction, taurodontism, open-bite malocclusion, attrition, reduced vertical dimension, tooth sensitivity, and increased caries risk [19]. Psychosocial consequences often include social withdrawal, embarrassment, and diminished self-confidence [9,20,21].

This case highlights the application of evidence-based treatment in an adult patient diagnosed with hypoplastic amelogenesis imperfecta. The patient’s chief concerns, which included enamel staining, abnormal tooth morphology, and diminished tooth size, align with the psychological challenges described in the literature [9,14,22]. Functional impairments, such as reduced masticatory efficiency and increased oral sensitivity, further emphasized the need for extensive rehabilitation [23].

The diagnosis included a comprehensive occlusal analysis, periodontal evaluation, and esthetic assessment, in accordance with established protocols [9,24]. The staged treatment plan, using provisional restorations to evaluate changes in OVD prior to definitive rehabilitation, aligns with the recommendations of Roma et al and others [9,17,22,25–27]. This approach is well documented in the literature [9,28,29].

Treatment varies with the dentition stage. In pediatric cases, preventive strategies include fluoride application, dental sealants, and reinforcement of oral hygiene. Interim restorations often employ glass ionomer cements or composite resins, while stainless steel crowns are recommended for molars to maintain vertical dimension and reduce sensitivity [30].

In cases of mixed dentition, adhesive restorations, composite veneers, or crowns fabricated from polymethyl methacrylate (PMMA) are recommended, with orthodontic referral advised for open-bite malocclusion. For permanent dentition, full-coverage restorations are the prevailing standard of care [9,14,22,31–33]. PFM crowns are favored for posterior teeth due to their mechanical strength, occlusal stability, and durability [27]. All-ceramic restorations are recognized for their superior aesthetic qualities and biocompatibility. For anterior teeth, lithium disilicate restorations are preferred for aesthetics and bonding reliability [23,24,34,35]. Veneers remain controversial due to potential bonding issues and inherent enamel defects [36,37]. Composite resins serve as temporary solutions but are prone to breakdown and discoloration [38]. Zirconia crowns are noted for their strength and aesthetic qualities, although their opacity might require aggressive tooth preparation. The literature emphasizes the significance of restoring OVD, correcting occlusal discrepancies, implementing an interdisciplinary approach, establishing anterior guidance, and employing full-coverage restorations [24,28,33].

Implants are an excellent fixed treatment option in advanced amelogenesis imperfecta cases where teeth are hopeless and require extraction. However, it is crucial to plan carefully and schedule extractions optimally for implant placement. This is to preserve the bone, which resorbs relatively quickly after tooth extraction. Moreover, in cases of minor bone deficiency, guided bone regeneration procedures are recommended to increase bone volume and facilitate correct implant placement [9]. Nevertheless, a study in which the cost implications of implant-based rehabilitation for amelogenesis imperfecta patients were assessed retrospectively found no statistically significant differences between implant cases and tooth-supported fixed prostheses in long-term cumulative treatment [39].

Another treatment option for challenging cases is orthodontic therapy and orthognathic surgery. Despite the prolonged nature of orthodontic treatment, which may last several years, satisfactory clinical outcomes can be achieved in patients with high levels of commitment. Several types of orthodontic appliances are available, including removable, functional, and fixed appliances, depending on the clinical picture of the case. Fixed appliances may encounter difficulties in cases with short crown height and undercuts, which can complicate appliance retention. Removable appliances may solve these problems. Aesthetics should be considered and enhanced wherever possible. Furthermore, orthognathic surgery can address skeletal challenges in occlusal alignment and maxillary vertical excess. However, this treatment option is case-based and cannot solve the aesthetics and color defects of the affected teeth, which require restorative intervention [40].

The use of PFM crowns for posterior teeth and lithium disilicate restorations for anterior teeth in this case reflects a balance between structural integrity and aesthetic appeal, consistent with the guidelines of Christensen [22] and Patil and Patil [37]. Veneers were excluded due to well-documented bonding challenges and marginal deficiencies in amelogenesis imperfecta teeth [36,41]. Crown lengthening addressed the reduced clinical crown length and enamel thickness typical in cases of amelogenesis imperfecta [23,42].

Our patient reported considerable post-treatment satisfaction, echoing previous reports suggesting that extensive oral rehabilitation can enhance self-esteem and social functioning [9,15,43]. However, challenges remain, particularly the extensive time and financial resources required, which may limit accessibility. Long-term success depends on meticulous oral hygiene, regular use of occlusal guards, and adherence to follow-up schedules [9,22,44].

A clinical trial by Lindunger and Smedberg, involving 15 patients with hypoplastic and hypomaturation amelogenesis imperfecta, reported a 99.5% success rate and an average restoration longevity of 60 months. Treatments included PFM crowns, veneers, ceramic crowns, all-ceramic restorations, and gold crowns. Similarly, a study by Chen et al of 8 patients aged 8–18 years treated with a combination of stainless steel crowns, laboratory-fabricated composite veneers, and direct and indirect crowns also reported positive outcomes, with only about 10 restorations failing [45,46].

Comprehensive oral rehabilitation for amelogenesis imperfecta typically follows the conventional phased approach, beginning with diagnostic wax-ups and provisional restoration to evaluate aesthetics and OVD, followed by definitive restoration once patient adaptation is confirmed. Successful management requires a multidisciplinary approach, including periodontics for implant placement and crown lengthening, oral and maxillofacial surgery for extractions and orthognathic surgeries, orthodontics for malocclusion or spacing issues, prosthodontics for definitive restorative solutions, and psychology for counseling and support. Research consistently demonstrates high success rates for full-coverage crowns in amelogenesis imperfecta patients, particularly when combined with diligent oral hygiene and consistent follow-up. For example, PFM crowns have shown survival rates exceeding 90% at 10 years, while lithium disilicate crowns have demonstrated excellent aesthetic and functional results over 5–7 years [26,47].

Future advances in biomimetic enamel substitutes, gene therapies, and artificial intelligence-driven prosthesis design may reduce the need for intricate prosthodontic rehabilitation [24,34,48]. Recent research favors conservative approaches using biomaterials that better replicate natural tooth structure, enhancing longevity while minimizing invasiveness [24]. Currently, for adult amelogenesis imperfecta patients, full-coverage crowns remain the recognized standard of care [17].

Conclusions

Amelogenesis imperfecta presents a lifelong restorative challenge requiring accurate diagnosis, interdisciplinary collaboration, and patient-centered care. In this case, the integration of an interdisciplinary periodontal, surgical, and prosthodontic intervention, employing the latest technological advances in occlusal analysis and management, and utilizing a superior combination material approach with PFM and lithium disilicate restorations, resulted in marked improvements in aesthetics, phonetics, and function for a young adult with hypoplastic amelogenesis imperfecta. The literature supports this approach of combining a high-strength material in posterior teeth with highly aesthetic restorations for anterior teeth, emphasizing a definitive full-coverage prosthesis. With committed patients and structured maintenance programs, long-term outcomes are favorable.