Dentinogenesis imperfecta (DI) is a
genetic disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
of
tooth development
Tooth development or odontogenesis is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. For human teeth to have a healthy oral environment, all parts of the tooth must develop during appropriate stag ...
. It is inherited in an
autosomal dominant
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...
pattern, as a result of mutations on chromosome 4q21, in the dentine sialophosphoprotein gene (DSPP).
It is one of the most frequently occurring autosomal dominant features in humans. Dentinogenesis imperfecta affects an estimated 1 in 6,000-8,000 people.
This condition can cause
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
to be discolored (most often a blue-gray or yellow-brown color) and translucent, giving teeth an
opalescent
Opalescence refers to the optical phenomena displayed by the mineraloid gemstone opalopalescent. 2019. In Noah Webster's 1828 American Dictionary of the English Language. Retrieved January 7, 2019, from https://1828.mshaffer.com/d/word/opale ...
sheen.
Teeth are also weaker than normal, making them prone to rapid wear, breakage, and loss.
These problems can affect baby (primary/deciduous) teeth alone, or both baby teeth and adult (permanent) teeth, with the baby teeth usually more severely affected.
Although genetic factors are the main contributor for the disease, any environmental or systemic upset that impedes calcification or metabolisation of calcium can also result in anomalous dentine.
Classification
Shield classification (1973)
This is the most widely used classification for dentinogenesis imperfecta, and sub-divides the condition into 3 types:
Type I
DI associated with
Osteogenesis Imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
(OI).
Type of DI with similar dental abnormalities usually an autosomal dominant trait with variable expressivity but can be recessive if the associated
osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
is of recessive type.
Recent genetic studies have identified that mutations in the genes coding for the
collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
type 1 proteins, ''COL1A1'' and ''COL1A2'', are associated with this type of DI.
Not all individuals with OI have dentinogenesis imperfecta, and the prevalence of DI varies depending on the sub-type of OI:
* Higher prevalence of DI among individuals with OI type III and IV at 43-82% and 37-100%, respectively
* Lower prevalence of DI among individuals with OI type I at 8-40%
* No data available for other OI sub-types
Type II
DI not associated with OI. Occurs in people without other inherited disorders (i.e.
Osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
). It is an autosomal dominant trait. A few families with type II have progressive hearing loss in addition to dental abnormalities. Also called hereditary opalescent dentin.
Type III
Brandywine isolate. This type is rare with occurrences only in the secluded populations in Maryland, USA.
Similar to DI type II, this type is also not associated with OI.
Its predominant characteristic is bell-shaped crowns, especially in the permanent dentition. Unlike Types I and II, it involves teeth with shell-like appearance and multiple pulp exposures.
Mutations in the gene coding for the ''
dentine sialophosphoprotein (DSPP)'' are associated with DI type II and III. DSPP is a polypeptide which gives rise to 3 proteins;
dentine sialoprotein (DSP), dentine glycoprotein (DGP), and
dentine phosphoprotein (DPP). The DPP protein is thought to contribute to
hydroxyapatite
Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the crystal unit cell comprises two entities. ...
crystal formation and growth, a fundamental crystal which is widely distributed in mineralised
dentin
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
e and
enamel. The function of the DGP and DSP proteins is not well understood.
Genetic studies have shown that type II and III may be the same sub-type of dentinogenesis imperfecta, differing only by the severity.
de La Dure-Molla, Foruner and Berdal (2015)
de La Dure-Molla, Foruner and Berdal (2015) have proposed a new classification to supersede the Shield Classification (1973). This new classification is designed to overcome the shortcomings of its predecessor, mainly the clinical difficulty in using the Shield classification due to the overlapping signs & symptoms between the sub-types.
In this classification, the authors propose that the DSPP (
dentine sialophosphoprotein) diseases, that is dentinogenesis imperfecta and dentine dysplasia, are jointly named "Dentinogenesis imperfecta", and sub-types are determined according to the severity of the condition. There are a few exceptions:
* Shields'
Dentine Dysplasia type I - this condition is unique in that it only affects root development, and is separately termed "radicular dentin dysplasia" in the new classification.
* Shields' Dentinogenesis Imperfecta type I - this sub-type is not acknowledged in this new classification as the authors deem it a different disease since it is a
syndrome
A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired ...
of
osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
Mild type
Primary (baby) teeth are moderately affected.
Permanent (adult) teeth are not discoloured, or the discolouration is mild (grey colour). Little or no
attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
(tooth wear) is evident. The crown of the teeth may be bulbous and markedly constricted at the
cemento-enamel junction (CEJ).
Radiographically, evidence of partial
pulp
Pulp may refer to:
* Pulp (fruit), the inner flesh of fruit
Engineering
* Dissolving pulp, highly purified cellulose used in fibre and film manufacture
* Pulp (paper), the fibrous material used to make paper
* Molded pulp, a packaging material
...
obliteration with a "thistle-shaped appearance".
Moderate type
Teeth are moderately discoloured (blue, grey or amber opalescent). More attrition is evident with shortening of crown height. Crowns may appear bulbous with prominent constriction at the CEJ.
Radiographically, the pulp is small or is totally obliterated. Roots appear thinner and shorter than average. There may be periapical pathology.
Severe type
Teeth are markedly discoloured (brown opalescent). The crowns are very short due to severe attrition. Crowns may appear bulbous with prominent constriction at the CEJ.
Radiographically, pulp appears large and the dentine layer is thin ("shell teeth" as described in Presentation section). Roots are thin and short. There may be multiple periapical pathologies.
Radicular dentin dysplasia
This sub-type is used in place of Shields' dentine dysplasia type I, in which only the roots of the teeth are affected.
Both primary and permanent teeth are affected.
The teeth appear normal clinically. Radiographically, the roots are shorter and fused together with a rounded apex.
Presentation
Clinical presentation
Clinical features include:
* Discoloured teeth - teeth may be amber, brown, blue or
opalescent
Opalescence refers to the optical phenomena displayed by the mineraloid gemstone opalopalescent. 2019. In Noah Webster's 1828 American Dictionary of the English Language. Retrieved January 7, 2019, from https://1828.mshaffer.com/d/word/opale ...
* Bulbous shape to the tooth crown due to cervical constriction
*
Tooth wear
Tooth wear refers to loss of tooth substance by means other than dental caries. Tooth wear is a very common condition that occurs in approximately 97% of the population. This is a normal physiological process occurring throughout life; but with in ...
/Non-carious tooth surface loss (NCTSL) - due to the poorly mineralised dentine, the
enamel of the tooth is unsupported and subsequently shears or chips off as it is subjected to biting forces. This exposes the underlying poorly mineralised dentine which is less resistant to wear. Therefore, features of
abrasion and
attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
may become apparent.
* Reduction in
occlusal vertical dimension (OVD) - this is secondary to the tooth wear/NCTSL. A reduced OVD can lead to craniofacial dysgnathia, poor tooth aesthetics, and disorders during chewing, swallowing, speaking and eating.
The baby (primary) teeth are usually more severely affected than adult (permanent) teeth.
Enamel is usually lost early because it is further inclined to attrition due to loss of scalloping at the
dentinoenamel junction
The dentinoenamel junction or dentin-enamel junction (DEJ) is the boundary between the enamel and the underlying dentin that form the solid architecture of a tooth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mout ...
(DEJ). It was suggested that the scalloping is beneficial for the mechanical properties of teeth as it reinforces the anchor between enamel and dentine. However, the teeth are not more susceptible to
dental caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
than normal ones.
Periodontal disease, or gum disease, is a common finding amongst individuals with dentinogenesis imperfecta despite no clinical findings of
tooth decay
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
(dental caries). The reason for this is currently not well understood.
Certain patients with dentinogenesis imperfecta will suffer from multiple
periapical abscesses apparently resulting from pulpal strangulation secondary to pulpal obliteration or from pulp exposure due to extensive coronal wear. They may need apical surgery to save the involved teeth.
Note that, although dentine exposure is a common clinical finding, individuals with dentinogenesis imperfecta usually do not experience
tooth sensitivity as the exposed dentine is typically sclerosed (hardened), thereby appearing glassy/shiny.
Radiographic presentation
Radiographic features include:
* Bulbous shape of tooth crown with pronounced cervical constriction
* Small
pulp
Pulp may refer to:
* Pulp (fruit), the inner flesh of fruit
Engineering
* Dissolving pulp, highly purified cellulose used in fibre and film manufacture
* Pulp (paper), the fibrous material used to make paper
* Molded pulp, a packaging material
...
, or total pulp obliteration
* Small or obliterated
root canal
A root canal is the naturally occurring anatomic space within the root of a tooth. It consists of the pulp chamber (within the coronal part of the tooth), the main canal(s), and more intricate anatomical branches that may connect the root ...
* Presence of pulp stones
* Narrow and small
roots
A root is the part of a plant, generally underground, that anchors the plant body, and absorbs and stores water and nutrients.
Root or roots may also refer to:
Art, entertainment, and media
* ''The Root'' (magazine), an online magazine focusing ...
* Periapical radiolucency without any evidence of clinical pathology such as
tooth decay
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
(dental caries)
Presentation by sub-type of Dentinogenesis Imperfecta
Clinical and radiographic features can be categorised by the sub-type of dentinogenesis imperfecta (see Shield's Classification in the Classification section):
Type I
Clinically, both the baby (primary) and adult (permanent) teeth often appear amber coloured and translucent, and show signs of severe
attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
. Primary teeth have a more obvious appearance as they have a thinner layer of enamel overlying dentine, hence the abnormal color of dentine is more noticeable.
Radiographically, affected teeth have short and narrow roots, and obliterated pulps due to dentine hypertrophy before or shortly after
tooth eruption
Tooth eruption is a process in tooth development in which the teeth enter the mouth and become visible. It is currently believed that the periodontal ligament plays an important role in tooth eruption. The first human teeth to appear, the decidu ...
.
The severity of these features is variable, with some teeth presenting with total obliteration of the pulp, while other teeth appear to have normal, healthy dentine.
Some type I cases present with no clinical findings, with only radiographic abnormalities.
Type II
Type II has a similar clinical and radiographic appearance to type I with some distinguishing features:
* Bulbous crowns are common with pronounced cervical constriction
* All teeth in the mouth are affected, with severe abnormalities present in both the baby (primary) and adult (permanent) teeth. This is in contrast to type I where the presentation is more variable
* Rarely, individuals exhibit
sensorineural hearing loss
Sensorineural hearing loss (SNHL) is a type of hearing loss in which the root cause lies in the inner ear or sensory organ (cochlea and associated structures) or the vestibulocochlear nerve (cranial nerve VIII). SNHL accounts for about 90% of rep ...
. It is proposed this hearing loss is a secondary feature to
attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
; this type of tooth wear can cause jaw overclosure with subsequent changes to the shape of the inner ear, thus causing hearing loss. However, the true cause remains unknown.
Type III
Similar clinical and radiographic features to that of type I and II are apparent for the adult (permanent) teeth. The main distinguishing feature is "shell teeth", a term used to describe the unique appearance of the baby (primary) teeth; the primary teeth have multiple pulp exposures and radiographically appear hollow as the dentine layer is thin (dentine hypotrophy) and the
pulp chamber
The pulp is the connective tissue, nerves, blood vessels, and odontoblasts that comprise the innermost layer of a tooth. The pulp's activity and signalling processes regulate its behaviour.
Anatomy
The pulp is the neurovascular bundle centr ...
is very large.
Histology
The
enamel has a regular structure, however, there are abnormalities in the structure of
dentin
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
e and at the
amelo-dentinal junction.
These abnormalities include:
* Fewer dentinal tubules
* Dentinal tubules may be of smaller diameter, irregular in shape, and may also be obliterated
* Abnormal morphology of apatite crystals
* Higher water and collagen content in the organic component of dentine (see Structure section on
dentin
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
page to learn more)
Diagnosis
To determine if the condition has been inherited, it is suggested to ask if any other family member has Dentinogenesis imperfecta. A lack of family history may indicate that the condition was acquired.
It is suggested that the dental/medical professional establish if the condition is a
syndrome
A syndrome is a set of medical signs and symptoms which are correlated with each other and often associated with a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". When a syndrome is paired ...
of another inherited condition such as:
*
Osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
- indicates Type I Dentinogenesis Imperfecta (see Shield's Classification in Classification section)
*
Ehlers Danlos syndrome
* Goldblatt syndrome
* Schimke immune-osseus dysplasia
* Brachio-skeleto-genital syndrome
* Osteodysplastic and primordial short stature with severe microdontia
* Opalescent teeth
* Rootless molars
his is not a comprehensive list
It can be useful to enquire about symptoms of
osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
, as Type I Dentinogenesis Imperfecta (Shield's Classification) is associated with osteogenesis imperfecta.
Notable information includes:
* History of bone fracture caused by minimal trauma
* Short stature
* Blue
sclera
The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some crucial elastic fiber. In humans, and som ...
* Hearing loss
Common dental features of osteogenesis imperfecta include:
*
Hypodontia
Hypodontia is defined as the developmental absence of one or more teeth excluding the third molars. It is one of the most common dental anomalies, and can have a negative impact on function, and also appearance. It rarely occurs in primary teet ...
*
Oligodontia
Hypodontia is defined as the developmental absence of one or more teeth excluding the third molars. It is one of the most common dental anomalies, and can have a negative impact on function, and also appearance. It rarely occurs in primary teet ...
*
Taurodontism
Taurodontism is defined as the enlargement of pulp chambers with the furcation area being displaced toward the apex of the root. It cannot be diagnosed clinically and requires radiographic visualization since the crown of a taurodontic tooth ap ...
* Unerupted permanent 2nd molars, with no obstruction in the path of eruption
* Retrognathic
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
Differential diagnosis
* Hypocalcified forms of
amelogenesis imperfecta
Amelogenesis imperfecta (AI) is a congenital disorder which presents with a rare abnormal formation of the enamel or external layer of the crown of teeth, unrelated to any systemic or generalized conditions. Enamel is composed mostly of mineral, ...
* Congenital erythropoietic
porphyria
Porphyria is a group of liver disorders in which substances called porphyrins build up in the body, negatively affecting the skin or nervous system. The types that affect the nervous system are also known as acute porphyria, as symptoms are ra ...
* Conditions that can cause early loss of teeth e.g.
Kostmann's disease,
cyclic neutropenia
Cyclic neutropenia (CyN) is a rare hematologic disorder and form of congenital neutropenia that tends to occur approximately every three weeks and lasting for few days at a time due to changing rates of neutrophil production by the bone marrow. It ...
,
Chediak-Hegashi syndrome,
histiocytosis X,
Papillon-Lefevre syndrome
* Permanent tooth
discolouration caused by medications such as
tetracyclines
Tetracyclines are a group of broad-spectrum antibiotic compounds that have a common basic structure and are either isolated directly from several species of ''Streptomyces'' bacteria or produced semi-synthetically from those isolated compounds. T ...
, or medical conditions such as
rickets
Rickets is a condition that results in weak or soft bones in children, and is caused by either dietary deficiency or genetic causes. Symptoms include bowed legs, stunted growth, bone pain, large forehead, and trouble sleeping. Complications may ...
Treatment
Preventive and restorative care are important as well as esthetics as a consideration. This ensures preservation of the patient's vertical face height between their upper and lower teeth when they bite together. The basis of treatment is standard throughout the different types of DI where prevention, preservation of occlusal face height, maintenance of function, and aesthetic needs are priority. Preventive efforts can limit pathology occurring within the pulp, which may render future endodontic procedures less challenging, with better outcomes.
* Challenges are associated with root canal treatment of teeth affected by DI due to pulp chamber and root canal obliteration, or narrowing of such spaces.
* If root canal treatment is indicated, it should be done in a similar way like with any other tooth. Further consideration is given for restoring the root-treated tooth as it has weaker dentine which may not withstand the restoration.
Preservation of occlusal face height may be tackled by use of stainless steel crowns which are advocated for primary teeth where occlusal face height may be hugely compromised due to loss of tooth tissue as a result of attrition, erosion of enamel.
In most cases, full-coverage crowns or veneers (composite/porcelain) are needed for aesthetic appearance, as well as to prevent further attrition.
Another treatment option is bonding, putting lighter enamel on the weakened enamel of the teeth and with many treatments of this bonding, the teeth appear whiter to the eye, but the teeth on the inside and under that cover are still the same. Due to the weakened condition of the teeth, many common cosmetic procedures such as braces and bridges are inappropriate for patients with Dentinogenesis imperfecta and are likely to cause even more damage than the situation they were intended to correct.
Dental whitening (bleaching) is contraindicated although it has been reported to lighten the color of DI teeth with some success; however, because the discoloration is caused primarily by the underlying yellow-brown dentin, this alone is unlikely to produce normal appearance in cases of significant discoloration.
If there is considerable attrition, overdentures may be prescribed to prevent further attrition of remaining teeth and for preserving the occlusal face height.
Management of DI associated with OI
Bisphosphonate
Bisphosphonates are a class of drugs that prevent the loss of bone density, used to treat osteoporosis and similar diseases. They are the most commonly prescribed drugs used to treat osteoporosis. They are called bisphosphonates because they ...
s have recently been introduced to treat several bone disorders, which include osteogenesis imperfecta.
A recognized risk of this drug relevant to dental treatments is
bisphosphonate-associated osteonecrosis of the jaw
Medication-related osteonecrosis of the jaw (MON, MRONJ) is progressive death of the jawbone in a person exposed to a medication known to increase the risk of disease, in the absence of a previous radiation treatment. It may lead to surgical compl ...
(BRONJ).
Occurrences of this risk is associated with dental surgical procedures such as extractions.
Dental professionals should therefore proceed with caution when carrying out any dental procedures in patients who have Type 2 DI who may be on bisphosphonate drug therapy.
See also
*
Dentin
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
*
Dentinogenesis {{Refimprove, date=September 2014
Dentinogenesis is the formation of dentin, a substance that forms the majority of teeth. Dentinogenesis is performed by odontoblasts, which are a special type of biological cell on the outer wall of dental pulps, an ...
*
Tooth development
Tooth development or odontogenesis is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. For human teeth to have a healthy oral environment, all parts of the tooth must develop during appropriate stag ...
*
Osteogenesis imperfecta
Osteogenesis imperfecta (; OI), colloquially known as brittle bone disease, is a group of genetic disorders that all result in bones that break easily. The range of symptoms—on the skeleton as well as on the body's other organs—may be mi ...
References
''This article incorporates public domain text fro
The U.S. National Library of Medicine'
External links
{{Tooth disease
Genetic disorders with no OMIM
Developmental tooth disorders