Introduction

Overview of Dentin Dysplasia type I (DD type I)

Dentin Dysplasia Type I is a rare inherited disorder characterized by normal crowns of teeth but with malformed roots, due to abnormal development of dentin.¹

Importance of early diagnosis in mixed dentition

Early identification of Dentin Dysplasia Type I (DD-I) in mixed dentition is extremely important since it presents with crowns that appear normal, yet the root formation is abnormal, resulting in mobility, premature loss of the tooth, and possible cyst/abscess formation.² A proper diagnosis is difficult due to insidious signs and symptoms. An accurate diagnosis becomes more difficult with varying development of DD-I signs in multiple teeth, making radiographs critical to detection.²

Dentin dysplasia type I: Pathophysiology and genetic basis

Genetic etiology

DD-I is a genetically heterogeneous disorder, with several genes associated with dental dysplasia, including VPS4B, SSUH2, and SMOC2, with many cases unexplained. DD-I demonstrates dominant inheritance and recessive inheritance (rarely). Future research is critical to improving the understanding of this disorder. Further research is also essential for practitioners and clinicians to provide accurate diagnosis and care.³

Developmental impact on dentin

(DD-I) generally represents an issue with root dentin; normally, crowns appear normal. DD-I primarily demonstrates pulp and root dentin. Recognizable features demonstrate short or absent roots, pulp chambers shaped like crescents, and periapical radiolucencies that contribute to increased mobility and tooth loss in primary and permanent teeth. In DD-I, the characteristics occur 'out of the blue', absence of dental caries, or previous dental trauma.⁴

Clinical features of dentin dysplasia type I

Primary teeth (Deciduous dentition)

DD-I is a unique inherited dental anomaly characterized by the presence of both primary and permanent teeth with normal or nearly normal crowns, but having short, malformed, or absent roots, almost closed pulp chambers, and increased tooth mobility. Primary teeth exhibit no enamel alterations but may have periapical radiolucencies and must be assessed for early exfoliation or the development of abscesses. Identifying the dentition and stages of eruption is important when identifying DD-I early in the mixed dentition stage.⁵ 

Permanent teeth (Mixed dentition)

In the permanent dentition, DD-I presents with characteristics similar to primary teeth, including normal crown morphology with short, malformed, or missing roots and nearly closed pulp chambers. Typically, DD-I observed in permanent teeth presents as severe tooth mobility, delayed eruption, premature loss of tooth, significantly short or absent roots, and frequent periapical radiolucencies regardless of caries or trauma.⁶

Early Signs to look for in mixed dentition

In the mixed dentition, potential indicators of DD-I include abnormal tooth mobility without clinical evidence of periodontal disease, short, blunted roots, no to or limited pulp connection, and premature loss of teeth. Finding these features may require taking appropriate radiographic assessments. DD-I typically occurs in association with abscesses or cysts in otherwise non-carious teeth and delayed eruption or protruding teeth.⁶

Diagnostic approach

Clinical examination

Teeth in patients with DD-I are characterized by normal crowns and excessive tooth mobility, with premature exfoliation that will often develop without a history of dental caries or trauma, but occasionally demonstrate the loss of an abscess.²

Radiographic examination

Diagnostic radiographs will document short, blunted, or absent roots with nearly closed pulp chambers. Patients present with periapical radiolucencies as a common finding on diagnostic radiographs; advanced imaging modalities (like micro-computed tomography [micro-CT]) can help provide details of their fused or malformed root and pulp morphology.²

Differential diagnosis

DD-I may be confused with DD-II, DGI, or odontodysplasia. This makes genetic testing important for establishing a diagnosis and distinguishing DD-I from other genetic dentin disorders.² 

Management and treatment

Conservative management

An early diagnosis coupled with preventative action is essential to slow down tooth loss; with careful monitoring of the patient, maintenance of their oral hygiene practices, and minimizing trauma, we can delay tooth loss as long as possible- especially relevant for kids and young adults.⁷ 

Restorative treatment and endodontic treatment

The goal of restorative treatments is to maintain teeth, with interventions facilitated by endodontic therapy only where root length and root anatomy permit. In many clinical situations, the morphology of canals is complicated enough to warrant extraction of teeth, often requiring prosthetic rehabilitation with implants, tragically, only after extraction.^8,9 

Long-term prognosis and follow-up

The prognosis will differ for each patient depending upon age at diagnosis of DD-I, root development, and dental and specialist care. A timely follow-up appointment for managing complications, downtime, and the prosthetic plan is crucial following the diagnosis, when many patients will have lost teeth.⁷

Summary 

(DD-I) It is a rare form of genetic disorder affecting root dentin while maintaining normal crown dentin. The principal characteristics of DD-I include: abnormally shortened or absent roots; obliterated pulp chambers; and periapical radiolucencies in the radiographs, demonstrating findings that can lead to mobility and premature tooth loss. Management considers preventive programs, restorative treatment approaches, and endodontics, although in cases of DD-I, with obliterated canals, may result in extractions and the placement of prosthetic rehabilitation. It is paramount to provide an early diagnosis and associated genetic testing that confirms an accurate diagnosis of DD-I and distinguishes it from other similar conditions.