Enamel infraction

Enamel infractions are microcracks seen within the dental enamel of a tooth. 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.

Reasons

Physiological

Destruction processes are activated by the reaction of the surface layer to internal and external irritations. Microfractures are caused by:

• eating foods that are too different in temperature (e.g., hot tea after cold ice cream);
• smoking in the cold (same as the first point, temperature contrast is created);
• excessive consumption of acidic fruits, juices and carbonated drinks;
• abuse of whitening toothpastes or using brushes that are too stiff;
• progression of caries or periodontitis.

Mechanical

Fracture occurs due to the forces exerted on the dental unit. The enamel is splintering:

• after an unfortunate fall, bump or contusion of the jaw;
• due to excessive chewing, eating too hard food, and chewing nuts and seeds;
• grinding of teeth and a bad habit of chewing on things, such as pencils, pens, etc.;
• due to stresses caused by the seal. Expansion over time of the silver amalgam creates stress in the body of the dental unit. This process contributes to chipping and even deep longitudinal cracking, up to and including breaking the tooth in half. Modern white fillings have a compression process going on. It also contributes to the stress from which horizontal cracks appear.

Signs and symptoms

An up-close look at enamel infractions reveals pits and grooves that show how developmental defects affect tooth structure and make teeth more susceptible to decay.

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's 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.

Cause and mechanism

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).

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.

Ameloblasts (the cells responsible for the production of enamel) don't 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 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.

An oral examination is being held and can be observed through the image.

Up above is the dental operating microscope where enamel infractions can be observed.

The transilluminator is the device she is working on used to observe enamel infractions.

Diagnosis

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's 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.

Treatment

Minor infractions may not require any treatment, however, major infractions may need treatment including smoothing, fluoride treatment, and crown restoration.

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.

Prognosis

Enamel infractions don't usually go beyond the enamel so they don't require any treatment because they don't 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. Most patients can continue normally with enamel infractions as long as the infraction doesn't get bigger or cause any complications.

Epidemiology

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. 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. 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.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's important to be preventive.

Research direction

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. 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. 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.