Enamel infractions are microcracks seen within the dental enamel of a tooth. [1] They are commonly the result of dental trauma to the brittle enamel, which remains adherent to the underlying dentine. They can be seen more clearly when transillumination is used.
Enamel infractions are found more often in older teeth, as the accumulated trauma is greatest. Enamel infractions can also be found as a result of iatrogenic damage inadvertently caused by instrumentation during dental treatments.
As of 2024, the prevalence of pathology reaches over 90%. In patients aged 20 years, an average of 4 intact teeth with enamel cracks are identified. Before 30 years of age, this rate increases 3 times and after 45–50 years of age it is 100%. In 60% of cases there are single fissures, multiple fissures are found in 40% of examined patients. In the study, researchers found that every decayed or treated tooth has deep multiple enamel cracks on its surface. In the prevailing majority of cases (90%) there are vertical longitudinal defects, less often the lines of enamel integrity violation have transverse direction, very rarely (3%) oblique enamel cracks are detected.
They are occasionally called caveated enamel fractures. It is a micro-fracture or superficial break in a tooth's enamel layer that does not go into the dentin underneath. Usually, trauma—like a direct blow to the tooth—or stress from too much pressure—like bruxism—causes these infractions. Enamel infractions, as opposed to cavities, may not need bacterial decay or tooth structure loss, although they may still result in sensitivity or cosmetic issues. To stop more harm, early detection via clinical examination or dental imaging is essential.
Monitoring the condition is often the first step in treatment, followed by preventative measures like applying fluoride or, in more extreme situations, restorative processes like veneers or dental bonding maintain tooth health and avoid more serious dental problems down the road, it is crucial to comprehend the nature of enamel infractions.
Destruction processes are activated by the reaction of the surface layer to internal and external irritations. Microfractures are caused by: [2] [3]
Fracture occurs due to the forces exerted on the dental unit. The enamel is splintering: [4] [5] [6]
Enamel infractions are typically asymptomatic, but if they persist for an extended period of time, they may cause problems, like making the enamel more sensitive to food and temperature. The only visible symptom, if it is able to be seen through the naked eye is minor microcracks. Additionally, because dentin is yellow-orange in comparison to enamel, which is a white or lighter tint, there may be dental discoloration. [7]
Enamel Infractions are described by the quality and quantity of enamel present throughout childhood. Various factors are involved in the development of infractions, some of these factors are nutritional, environmental, genetic, and systemic factors. Structural abnormalities stem from genetic mutations that change the normal proteins necessary for enamel formation but due to a lack of essential nutrients like calcium, vitamin D, and vitamin A contribute to these genetic factors. This lack of vitamins slows down the formation and mineralization of enamel during crucial stages of enamel development in early childhood. Environmental factors that also play a role are an excess of fluoride exposure during enamel development (which can cause fluorosis [8] ).
The primary cause of enamel wear in the grooves is the direct mechanical forces applied during chewing, such as vertical pressure and lateral forces as teeth grind or shear food. Particularly in areas where food is more frequently trapped or where contact is poor, the continuous friction between the food and the tooth surface causes abrasion, which slowly destroys the enamel in the grooves. Repeated mastication can cause fatigue damage to the enamel. As individuals age, the enamel on molars may naturally thin, making it more prone to damage during mastication. [9]
Ameloblasts (the cells responsible for the production of enamel) do not function properly due to other factors like infections, trauma, or severe illness that occur similarly in the development of the enamel. All these factors combined in early childhood can reduce ameloblast activity which can result in insufficient enamel matrix protein secretion. As a result, the organic matrix could not be correctly formed or mineralized with hydroxyapatite [10] crystals that leads to poor mineralization of the enamel. This can lead to a weakened enamel surface that is more porous, thinner, prone to pits and grooves which raises the risk of dental caries and sensitivity.
Enamel infractions are diagnosed through a dental examination. A dentist can assess the teeth's condition once the first tooth erupts in the mouth and will continue to do so throughout every appointment. In order for the provider to take preventive action depending on the health of the teeth or any abnormalities, it is important that a child has a dental examination during the early years of tooth development and continue with check ups throughout their life. A dental examination would also be routine to identify this if it were discovered later in life. Methylene blue staining, dental operating microscope magnification, and the transilluminator are commonly used methods for crack diagnosis. Even though cracks can be found with these methods, it is very difficult to pinpoint the exact size and depth of a crack. [11]
Minor infractions may not require any treatment, however, major infractions may need treatment including smoothing, fluoride treatment, and crown restoration. [12]
Other treatments include restoration, where there is an overlay of material on the tooth to harden and make it a tooth-like structure. Even uncomplicated patients who show no strong effects can be recommended to undergo a crown restoration to be preventive and frequently x-rayed to stay updated on the condition of the tooth. For older patients, it is suggested to only do a crown restoration if there is no infection present. Older patients are more impacted in eating and daily life by the loss of their teeth so dentists try to minimize this by placing a crown.
Enamel infractions do not usually go beyond the enamel so they do not require any treatment because they do not cause any infections. Any treatment necessary is mostly for patients with concerns on the appearance of the tooth. If they want to and are able to, they can get a crown or veneers. [13] Most patients can continue normally with enamel infractions as long as the infraction does not get bigger or cause any complications.
One of the most common dental traumas are enamel infractions. Despite their high frequency, enamel infractions are often underreported, because they are typically asymptomatic and may not be easily noticeable without a clinical evaluation or an x-ray. Demographic evaluations indicate a higher prevalence of trauma in males compared to females, particularly in younger populations. [14] Studies have consistently shown that males are more likely to experience dental trauma, with some studies reporting a male-to-female ratio of up to 2:1 in children and adolescents. This higher prevalence is often associated to behavioral factors such as greater involvement in contact sports, physical activities, and risk-taking behaviors. Additionally, males tend to engage in more high-risk activities, which increases their exposure to trauma that may result in enamel infractions. [14] However, it is important to note that while enamel infractions are more common in males, they can affect individuals of all ages and genders, especially when there are contributing factors such as bruxism or malocclusion. More than 75% of tooth fractures occur in the upper jaw, with the majority affecting the anterior teeth—particularly the central incisors, followed by the lateral incisors and canines. This trend highlights the vulnerability of these teeth to trauma, often resulting in enamel infractions or more extensive fractures. [15] Despite their frequency, enamel infractions are often underreported, as they are typically asymptomatic and may not be easily noticeable without a detailed clinical assessment or x-ray which is why it is important to be preventive.
Infiltrant resin application is a promising minimally invasive technique for superficial enamel cracks that can improve functionality and appearance. The two case studies illustrate the method's conservative nature and present a viable option for patients with enamel infractions who would prefer not to undergo more invasive procedures. [16] In another article, it emphasizes how the detection of enamel cracks has greatly improved due to recent technological advancements like transillumination, OCT, and AI. In an article focused on the advancements of AI allows especially for the diagnosis, localization, classification, estimate, and evaluation of oral disease in the field of dentistry. Given how quickly AI technology has developed recently, it can allow early detection or signs of these enamel infractions and help create a treatment plan. [17] Effective treatment and the avoidance of more serious damage depend on an early and precise diagnosis. As these technologies advance, they might provide more accurate, non-invasive, and economical methods of detecting enamel cracks, improving dental care outcomes. [18]
Human teeth function to mechanically break down items of food by cutting and crushing them in preparation for swallowing and digesting. As such, they are considered part of the human digestive system. Humans have four types of teeth: incisors, canines, premolars, and molars, which each have a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food. The roots of teeth are embedded in the maxilla or the mandible and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Bruxism is excessive teeth grinding or jaw clenching. It is an oral parafunctional activity; i.e., it is unrelated to normal function such as eating or talking. Bruxism is a common behavior; the global prevalence of bruxism is 22.22%. Several symptoms are commonly associated with bruxism, including aching jaw muscles, headaches, hypersensitive teeth, tooth wear, and damage to dental restorations. Symptoms may be minimal, without patient awareness of the condition. If nothing is done, after a while many teeth start wearing down until the whole tooth is gone.
Trismus is a condition of restricted opening of the mouth. The term was initially used in the setting of tetanus. Trismus may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more frequently than permanent trismus. It is known to interfere with eating, speaking, and maintaining proper oral hygiene. This interference, specifically with an inability to swallow properly, results in an increased risk of aspiration. In some instances, trismus presents with altered facial appearance. The condition may be distressing and painful. Examination and treatments requiring access to the oral cavity can be limited, or in some cases impossible, due to the nature of the condition itself.
Toothaches, also known as dental pain or tooth pain, is pain in the teeth or their supporting structures, caused by dental diseases or pain referred to the teeth by non-dental diseases. When severe it may impact sleep, eating, and other daily activities.
Acid erosion is a type of tooth wear. It is defined as the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Dental erosion is the most common chronic condition of children ages 5–17, although it is only relatively recently that it has been recognised as a dental health problem. There is widespread ignorance of the damaging effects of acid erosion; this is particularly the case with erosion due to consumption of fruit juices because they tend to be seen as healthy. Acid erosion begins initially in the enamel, causing it to become thin, and can progress into dentin, giving the tooth a dull yellow appearance and leading to dentin hypersensitivity.
Abfraction is a theoretical concept explaining a loss of tooth structure not caused by tooth decay. It is suggested that these lesions are caused by forces placed on the teeth during biting, eating, chewing and grinding; the enamel, especially at the cementoenamel junction (CEJ), undergoes large amounts of stress, causing micro fractures and tooth tissue loss. Abfraction appears to be a modern condition, with examples of non-carious cervical lesions in the archaeological record typically caused by other factors.
In orthodontics, a malocclusion is a misalignment or incorrect relation between the teeth of the upper and lower dental arches when they approach each other as the jaws close. The English-language term dates from 1864; Edward Angle (1855–1930), the "father of modern orthodontics", popularised it. The word derives from mal- 'incorrect' and occlusion 'the manner in which opposing teeth meet'.
A dental emergency is an issue involving the teeth and supporting tissues that are of high importance to be treated by the relevant professional. Dental emergencies do not always involve pain, although this is a common signal that something needs to be looked at. Pain can originate from the tooth, surrounding tissues or can have the sensation of originating in the teeth but be caused by an independent source. Depending on the type of pain experienced an experienced clinician can determine the likely cause and can treat the issue as each tissue type gives different messages in a dental emergency.
Dilaceration is a developmental disturbance in shape of teeth. It refers to an angulation, or a sharp bend or curve, in the root or crown of a formed tooth. This disturbance is more likely to affect the maxillary incisors and occurs in permanent dentition. Although this may seem more of an aesthetics issue, an impacted maxillary incisor will cause issues related to occlusion, phonetics, mastication, and psychology on young patients.
Dentin hypersensitivity is dental pain which is sharp in character and of short duration, arising from exposed dentin surfaces in response to stimuli, typically thermal, evaporative, tactile, osmotic, chemical or electrical; and which cannot be ascribed to any other dental disease.
Macrodontia is a type of localized gigantism in which teeth are larger than normal. Macrodontia seen in permanent teeth is thought to affect around 0.03 to 1.9 percent of the worldwide population. Generally, patients with macrodontia have one or two teeth in their mouth that is abnormally large; however, single tooth growth is seen in a number of cases as well.
Dens invaginatus (DI), also known as tooth within a tooth, is a rare dental malformation and a developmental anomaly where there is an infolding of enamel into dentin. The prevalence of this condition is 0.3 - 10%, affecting males more frequently than females. The condition presents in two forms, coronal involving tooth crown and radicular involving tooth root, with the former being more common.
Dental attrition is a type of tooth wear caused by tooth-to-tooth contact, resulting in loss of tooth tissue, usually starting at the incisal or occlusal surfaces. Tooth wear is a physiological process and is commonly seen as a normal part of aging. Advanced and excessive wear and tooth surface loss can be defined as pathological in nature, requiring intervention by a dental practitioner. The pathological wear of the tooth surface can be caused by bruxism, which is clenching and grinding of the teeth. If the attrition is severe, the enamel can be completely worn away leaving underlying dentin exposed, resulting in an increased risk of dental caries and dentin hypersensitivity. It is best to identify pathological attrition at an early stage to prevent unnecessary loss of tooth structure as enamel does not regenerate.
Cracked tooth syndrome (CTS) is where a tooth has incompletely cracked but no part of the tooth has yet broken off. Sometimes it is described as a greenstick fracture. The symptoms are very variable, making it a notoriously difficult condition to diagnose.
Dental trauma refers to trauma (injury) to the teeth and/or periodontium, and nearby soft tissues such as the lips, tongue, etc. The study of dental trauma is called dental traumatology.
Tricho–dento–osseous syndrome (TDO) is a rare, systemic, autosomal dominant genetic disorder that causes defects in hair, teeth, and bones respectively. This disease is present at birth. TDO has been shown to occur in areas of close geographic proximity and within families; most recent documented cases are in Virginia, Tennessee, and North Carolina. The cause of this disease is a mutation in the DLX3 gene, which controls hair follicle differentiation and induction of bone formation. All patients with TDO have two co-existing conditions called enamel hypoplasia and taurodontism in which the abnormal growth patterns of the teeth result in severe external and internal defects. The hair defects are characterized as being rough, course, with profuse shedding. Hair is curly and kinky at infancy but later straightens. Dental defects are characterized by dark-yellow/brownish colored teeth, thin and/or possibly pitted enamel, that is malformed. The teeth can also look normal in color, but also have a physical impression of extreme fragility and thinness in appearance. Additionally, severe underbites where the top and bottom teeth fail to correctly align may be present; it is common for the affected individual to have a larger, more pronounced lower jaw and longer bones. The physical deformities that TDO causes become more noticeable with age, and emotional support for the family as well as the affected individual is frequently recommended. Adequate treatment for TDO is a team based approach, mostly involving physical therapists, dentists, and oromaxillofacial surgeons. Genetic counseling is also recommended.
Tooth mobility is the horizontal or vertical displacement of a tooth beyond its normal physiological boundaries around the gingival (gum) area, i.e. the medical term for a loose tooth.
Tooth ankylosis refers to a fusion between a tooth and underlying bony support tissues. In some species, this is a normal process that occurs during the formation or maintenance of the dentition. By contrast, in humans tooth ankylosis is pathological, whereby a fusion between alveolar bone and the cementum of a tooth occurs.
Molar incisor hypomineralisation (MIH) is a type of enamel defect affecting, as the name suggests, the first molars and incisors in the permanent dentition. MIH is considered a worldwide problem with a global prevalence of 12.9% and is usually identified in children under 10 years old. This developmental condition is caused by the lack of mineralisation of enamel during its maturation phase, due to interruption to the function of ameloblasts. Peri- and post-natal factors including premature birth, certain medical conditions, fever and antibiotic use have been found to be associated with development of MIH. Recent studies have suggested the role of genetics and/or epigenetic changes to be contributors of MIH development. However, further studies on the aetiology of MIH are required because it is believed to be multifactorial.
An enamel fracture is when the outermost layer of the tooth is cracked, without damaging the inner layers including the dentine or pulp. This can happen from trauma such as a fall where the teeth are impacted by a hard object causing a chip to occur.