Dental caries, explanation of its origin
Classification of dental caries from various point of view
Faezeh Khojasteh, Abbas Vasilehbar, Sanaz Malali
Tooth decay, also known as dental caries or cavities, is a breakdown of teeth due to acids
made by bacteria. The cavities may be a number of different colours from yellow to black.
Symptoms may include pain and difficulty with eating Complications may include
inflammation of the tissue around the tooth, tooth loss, and infection or abscess formation
which can be an irreversible microbial disease of the calcified tissue of the teeth,
characterized by demineralization of the inorganic portion and inorganic destruction of the
the tooth, which often leads to cavitation.
Dental caries can be categorised based on the:
- Anatomical site
- progression
- virginity of lesion
- extend of caries
- tissue involvement
- pathway of caries
- number of tooth surface involved
- chronology
- whether caries is completely removed or not
- Tooth surface to be restored
- Black’s classification
- WHO system
Anatomical site
- Occlusal (pit and fissures)
All caries bacteria rapidly colonize the pits and fissures of the newly erupted teeth. These
early colonizers form a "bacterial plug" that remains in the site for long time, perhaps even
the life of the tooth. Type and nature of the organisms prevalent in the oral cavity determine
the type of organisms colonizing the pit and fissure. Numerous gram positive cocci, especially
dominated by s.sanguis are found in the newly erupted teeth. Shape, morphological variation
and depth of pit and fissures contributes to their high susceptibility to caries
- Smooth surface caries (proximal and cervical caries)
Less favorable site for plaque attachment, usually attaches on the smooth surface that are
near the gingiva or are under proximal contact. In very young patients the gingival papilla
completely fills the interproximal space under a proximal contact and is termed as col. Also
crevicular spaces in them are less favorable habitats for s.mutans. Consequently proximal
caries is less lightly to develop where this favorable soft tissue architecture exists.
- Linear enamel caries
Linear enamel caries odontoclasia is seen to occur in the region of the neonatal line of the
maxillary anterior teeth. The line, which represent a metabolic defect such as hypocalcemia
or trauma of birth, may predispose to caries, leading to gross destruction of the labial surface
of the teeth. Morphological aspects of this type of caries are atypical and results in gross
destruction of the labial surfaces incisor teeth
- Root caries
The proximal root surface, particularly near the cervical line, often is unaffected by the action
of hygiene procedures, such as flossing, because it may have concave anatomic surface
contous (Aueng) and occasional roughness at the termination of the enamel. These
conditions, when coupled with exposure to the oral environment (as a result of gingival
recession), favor the formation of mature, caries-producing plaque and proximal root-surface
caries. Root-surface caries is more common in older patients. Caries originating on the root is
alarming because: it has a comparatively rapid progression, it is often asymptomatic, it is
closer to the pulp, it is more difficult to restore
Progression
- acute
Of abrupt onset, in refrence to a disease. Acute often also connotes an illness that is of short
duration, rapidly progressive and in need of urgent care
- chronic
This is especially known for diseases. Any disorder leads to gum disease or cavities with an
immediate reaction of the body immune system.
- arrested
Good nutrition plays a part in preventing as well as arresting decay. Only active caries lesions
require treatment. Arrested caries is often a dark brown stain that seems ingrained in the
tooth and won't come off when it is polished.
Virginity of lesion
- Primary caries, No caries before at this spot
- Secondary caries, Next to filling,originates at borders
- Recurrent caries, Under the filling-insufficient excavation of caries
Extend of caries
- Incipient caries
The early caries lesion, best seen on the smooth surface of teeth, is as a white spot
Histologically the lesion has an apparently intact surface layer overlying subsurface
demineralization. Significantly may such lesion can undergo, remineralization and thus the
lesion is not an indication for restorative treatment
- cavitation
Occult carious lesion are usually seen with low caries rate which is suggestive of increase fluid
exposure. These hidden lesions are called as fluoride bombs or fluoride syndrome. Recently
it is seen that occult caries may have its origin as pre-eruptive defects which are detectable
only with the use of radiographs.
- Occult caries
Once it reaches the dentinoenamel junction, the caries process has the potential to spread to
the pulp along the dentinal tubules and also spread in lateral direction. Thus, some amount
of sensitivity may be associated with this type of lesion. This may be generally accompanied
by cavitation.
Tissue involvement
- Initial caries, Demineralization without structural defect. This stage can be reversed
by fluoridation and enhanced mouth hygiene
- superficial caries, Enamel caries, wedge-shaped structural defect, Caries has affected
the enamel layer, but has not yet penetrated the dentin.
- Moderate caries, dentin caries. Extensive structural defect, Caries has penetrated up
to the dentin and spreads two-dimensionally beneath the enamel defect where the
dentin offers little resistance.
- Deep caries, structural defect, caries has penetrated up to the dentin layers of the
tooth close to the pulp
- Deep complicated caries, Caries has led to the opening of the pulp cavity (pulpa aperta
or open pulp)
Pathway of caries
"Forward-backward" classification is considered as graphical representation of the pathway
of dental caries.
a) b)
Figure1. A) forward caries B) backward caries
Numbers of tooth surface involved
- Simple, a caries involving only one tooth surface
- Compound, a caries involving two surfaces of tooth
- Complex, a caries that involves more than two surfaces of a tooth
Chronology
- EARLY CHILDHOOD CARIES
- ADULT CARIES
- Adolescent CARIES
Whether caries is completely removed or not during treatment
- Residual caries is that which is not removed during a restorative procedure, either by
accident, neglect or intention.
- Sometimes a small amount of acutely carious dentin close to the pulp is covered with
a specific capping material to stimulate dentin deposition.
- The carious dentin can be removed at the later time.
Surface to be restored
Most widespread clinical utilization: O, Occlusal; M, mesial; D, distal; F, facial; B, buccal; L,
lingual surfaces. Various combinations are also possible, such as MOD, for mesio-occlusodistal
surfaces.
Black’s classification
Greene Vardiman Black (1836–1915), commonly known as G.V. Black, is known as one of the
founders of modern dentistry in the United States.[1] He is also known as the father of
operative dentistry. He organized 'Black's Classification of Caries Lesions' which is still in use
today. Since that time, only one more category has been added to his classification system.
- Class I Caries affecting pits and fissures on occlusal third of molars and premolars,
occlusal two thirds of molars and premolars, and Lingual part of anterior teeth
- Class II Caries affecting proximal surfaces of molars and premolars
- Class III Caries affecting proximal surfaces of central incisors, lateral incisors, and
cuspids without involving the incisal angles
- Class IV Caries affecting proximal including incisal angles of anterior teeth
- Class V Caries affecting gingival 1/3 of facial or lingual surfaces of anterior or posterior
teeth
- Class VI (never described by Black, added later by W J Simon in 1956) Caries affecting
cusp tips of molars, premolars, and cuspids
Figure2. GV Black Classification of Restorations
World health organization (WHO)
In this classification the shape and depth of the caries lesion scored on a four-point scale;
- Clinically detectable enamel lesion with intact (not cavitatetd) surfaces
- Clinically detectable cavities limited to enamel
- Clinically detectable cavities in dentin
- Lesion extending into the pulp