Author : DR SHAMIMUL HASAN

ABSTRACT

Developmental disturbances of structures of tooth particularly enamel and dentin are described in the literature as different entities. Abnormal dentin formation with incomplete root formation is seen in Dentin dysplasia.  Disturbances in the development of dentin may also occur, in the form of atypical dentin formation with obliteration of pulp as in Dentinogenesis imperfecta. Dentinogenesis imperfecta (DI), which is sometimes an accompanying symptom of Osteogenesis imperfect (OI), belongs to a group of genetically conditioned dentin dysplasias and is characterized by an opalescent amber appearance of the dentin. This paper deals with a case of dentinogensis imperfecta in an 18 year old female patient. The patient reported to the hospital with a chief complaint of unaesthetic appearance of her teeth.

INTRODUCTION

Dentinogenesis imperfecta is also known as Capdepont’s teeth, Hereditary opalescent dentin, Hereditary brown teeth etc.1 DI is a genetic disease, transmitted as an autosomal dominant trait,  and characterized by a disturbance of dentin formation. 2,3 The primary anomalies of DI are in the structure and composition of the dentin and result from abnormalities of dental papillae (mesenchymal portion of the tooth germ)4 The condition was first recognized by Barret in 1882. 5 The term “ Dentinogenesis imperfecta” was coined by Robert and Schour in 1939. The first published report describing the disorder as an enamel defect was by Talbot as quoted by Witkop. 6 The term “Hereditary opalescent dentin” was first used by Skillen7, Finn8 and Hodges9.   Clinically, both the deciduous and permanent dentition is affected. The affected teeth have opalescent, amber color , darkens with age , and exhibits pronounced attrition of incisal and occlusal surfaces.3 Shield’s et al classified Dentinogenesis imperfecta based on phenotypic variability.10

Type –I DI - that occurs with Osteogenesis imperfecta

Type-II DI – not associated with Osteogenesis imperfecta : also known as Hereditary opalescent dentin.

Type –III DI - DI of the “BRANDYWINE TYPE” ; affects teeth of a racial isolate in southern Maryland.

However the revised classification for DI is as follows:

DI TYPE-I - DI without OI –Opalescent dentin (corresponds to DI type II of Shield’s classification)

DI TYPE –II - Brandywine type DI (corresponds to DI type III of Shield’s classification)

Radiographically, the teeth have bulbous crowns and constricted, short roots. Initially, the pulp chambers may be abnormally wide, giving the appearance of ‘shell teeth’, but they progressively get obliterated11. Histologically the dentin is composed of irregular tubules, often with large areas of uncalcified matrix. The tubules tend to be larger in diameter and less numerous in a given volume of dentin than in normal teeth.12 The treatment strategy is focused towards protecting teeth from further wear and tear and total oral rehabilitation of patient with paramount importance to aesthetics, obtaining an appropriate vertical dimension and providing soft tissue support which will help to return the facial profile to a more normal appearance. A multidisciplinary treatment planning is required for treatment of these individuals.

CASE REPORT :

An 18 year old female patient reported to the department of Oral Medicine and Radiology, Z.A Dental college and Hospitals, A.M.U, Aligarh with a complaint of poor aesthetics due to rapid wearing of the tooth surface. The family history suggested that the patient was born to parents who had consanguinous marriage. The patient’s parents were also suffering from the similar condition of rapid wearing of teeth and had undergone total extraction at an early age. No history of any bone abnormality was associated with any of the family members. There was a history of similar discoloration of deciduous dentition, which exfoliated uneventfully. The permanent teeth were delayed in their eruption and were brown in color at the time of eruption.
On extra- oral examination: Slight bluish discoloration of the sclera was noticed (FIG 1). Intra- oral examination revealed that the teeth were brownish-yellowish in color (FIG 2). There was attrition in relation to posterior teeths (FIG 3). The upper anterior teeth showed fractured incisal edges with pulp exposure and anterior open bite. The associated teeth were tender on percussion.

Slight blue sclera

Brownish- Yellowish Discoloration of teeth with fractured Incisal edges in relation to 21

Attrition pattern in posterior teeth

Taking into consideration, history of consanguinous marriage, brownish- yellowish discoloration of deciduous and permanent dentition, a provisional diagnosis of Dentinogenesis Imperfecta was made.

Complete pulp obliteration of teeth with periapical radiolucencies.

The patient was further subjected to radiographic investigations. Orthopantamogram revealed complete obliteration of pulp chambers (except 18, 37,38,47,48) with periapical radiolucencies in relation to 13, 16,  21, 26, 37, 46.  Short roots with open apices in relation to 18, 28, 38 were noticed [FIG 4].

DISCUSSION

Although the terms Dentinogenesis imperfecta and hereditary opalescent dentin have been used interchangeably for more than 4o years, Witkop is of the opinion that they are two distinct entities. Dentinogenesis imperfecta is the tooth defect that accompanies Osteogenesis imperfecta , and hereditary opalescent dentin is an isolated tooth defect. Shield’s et al11 recognized 3 types of Dentinogenesis imperfecta. Type I is associated with Osteogenesis imperfect, & Type II has not been reported to demonstrate enlarged pulp chambers, occasionally seen in Type III. Levin et al 13 also reports enamel pitting in patients with Type III disease. Also, periapical radiolucency has been reported at the apices of teeth without pulp exposures in Type III, but not Type II. Although they share clinical, radiographic, and dental features that are characterstic of both conditions, we refer to the to defect as  Dentinogenesis imperfecta for convenience and because this is the term that most dentists associate with this condition. Dentinogenesis imperfect is an autosomal dominant disturbance of high penetrance, and occurs with equal frequency in both sexes. It is manifested in both the deciduous and permanent dentitions, and primarily in whites.14 It was once thought to be only a defect of the dentin, (and this idea still persists), but it has been observed that the enamel is not of normal thickness, nor has it been clearly established that the ease with which the enamel fractures away from the dentin is not caused by a basic fault in the enamel15.

CLINICAL FEATURES:

The appearance of the teeth is characterstic, with a high degree of amber like translucency and a variety of colors from yellow to blue-grey: the colors change according to whether the teeth are observed by transmitted or reflected light14. The enamel easily fractures from the teeth and the crowns readily wear, in adults, frequently to the gingiva8. The exposed dentin is stained, and the color of the abraded teeth may change further to dark brown or even black. Some patients will demonstrate an Anterior open bite.

RADIOGRAPHIC FEATURES:

The images of the crowns will probably be normal in size, but with a constriction of the cervical portion of the tooth that imparts a bulbous appearance. A slight to marked attrition of the occlusal surface may be evidenced on the radiograph, and the roots are usually short and slender. There may be partial or complete obliteration of the pulp chambers, and the root canals may be absent or thread like. Some areas of periapical radiolucencies may be found associated with sound teeth without evidence of pulpal involvement, but they donot occur as frequently as in dentin dysplasias. Although the periodontal ligament space may be widened, it is usually of normal thickness16. The architecture of the bone in the maxilla and mandible is normal.

DIFFERNTIAL DIAGNOSIS:

The differential diagnosis for DI includes Dentin Dysplasia. As these two conditions seem to form a continuum, with similarities including the potential to affect the color of the deciduous  and permanent teeth, and both initiating about the same time, their differentiation may be difficult. Both entities may have occluded pulp chambers, but at least in Type II Dentin Dysplasia the pulp chambers are never filled before eruption.Also, if Thistle –tube shaped pulp chambers are observed in the single rooted teeth, the probability of dentin dysplasia is strengthened. In addition, the size will help distinguish between the two : the teeth in opalescent dentin have typical “ BELL- SHAPED “ crowns with a constriction in the cervical region, whereas the crowns in Dentin Dysplasia are usually normal in shape, size, and properties. Ithe roots are short and narrow, the condition is likely to be Opalescent Dentin. On the other hand, normal appearing roots or practically no roots at all should suggest dentin dysplasia. Periapical rarefaction in association with non carious teeth are strong presumptive evidence that the condition is dentin dysplasia: they are seldom found in opalescent dentin.

TREATMENT:

The treatment strategy for patient suffering from dentinogenesis imperfecta should be targeted towards protecting the remaining hard tissues, restoration of stomatognathic system17. There are several alternatives for complete reconstruction of mouth in patient with dentinogenesis imprefecta (DI). Prosthodontic treatment planning includes consideration of function, aesthetics and vertical dimension. In cases involving extensive attrition overdentures or implants are an option3. As in all extensive prosthetic and restorative therapy, the treatment goal is focused on preservation of function and aesthetics. During treatment planning several factors have to be taken into account , such as age of the patient , quality of the existing dental tissues, the periodontal condition , pulp root anomalies , the loss of tooth structure and orthodontic condition 18. Depending on various factors the treatment options may vary. The distinctive radiographic appearance of DI is critical in establishing the exact diagnosis. The difficulty or impossibility of performing endodontic treatment due to the anatomy of the DI affected teeth makes treatment planning more critical 17 .

One of the greatest challenges for the pediatric dentist is to provide adequate treatment to achieve functional and esthetic restoration in cases of diseases like dentinogenesis imperfecta. Early diagnosis and treatment are essential for obtaining a favorable prognosis, any delay in intervention making the treatment even more complex. 19

Many treatment modalities have been suggested, eg, over-dentures, stainless steel crowns, jacket crowns, pin-retained cast-gold 'thimbles' under acrylic resin crowns, stainless steel crowns with acrylic facing, and simple removable appliances. 20 The use of a combination of partial dentures and prosthetic crowns on the anterior teeth has also been described. Orthodontic treatment has been successfully performed in patients with different degrees of dentinogenesis imperfecta. 20

Steel crowns used to prevent attrition of the dental structure can be used in deciduous teeth and in young permanent posterior teeth, where esthetics is not an issue. According to Wei such a procedure must be undertaken as soon as the tooth erupts. 21

Shafer et al . emphasize that restorations cannot be permanent owing to the diminished hardness of dentin.  Consequently, when fractures occur at the gingival level or below the gum, exodontia is indicated, as in the case of teeth that exhibit periapical rarefaction and root fracture. 20,21

When dealing with deciduous and young permanent anterior teeth, celluloid crowns are recommended; permanent molars should receive full cast crowns; metalloceramic restorations are recommended for premolars; and permanent anterior teeth should be restored with esthetic facets. 19

CONCLUSION

Patients with DI condition present with different degrees of severity. There is a need for classification of DI based on different degrees of severity to recommend treatment guidelines based on the category of the condition.

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