White spot lesions (WSLs) represent an early form of tooth decay, appearing as opaque, chalky marks on the enamel surface. These spots are a common concern for patients undergoing orthodontic treatment with fixed appliances. The presence of brackets and wires creates surfaces and crevices that easily trap food particles and plaque, making thorough cleaning difficult. White spots are areas of demineralization, or mineral loss, in the enamel that become noticeable once the braces are removed.
The Mechanism and Frequency of White Spot Lesions
White spot lesions form when the balance between mineral loss and gain in the enamel is disrupted. Bacteria in dental plaque consume sugars and produce acid, which dissolves calcium and phosphate minerals beneath the tooth’s surface. This acid erosion, known as demineralization, creates microscopic pores in the enamel layer.
The change in the mineral structure causes light to scatter differently than it does on healthy enamel, resulting in the characteristic matte, white appearance. WSLs are often most visible immediately after the appliances are removed, typically appearing as a white halo surrounding the area where the bracket was bonded.
Studies show that WSLs are a common occurrence in orthodontics. The percentage of patients who develop at least one new lesion during treatment can fall between 23% and over 50%. Other studies using highly sensitive measurement tools have reported the prevalence to be as high as 68% of patients.
The severity and number of lesions are dependent on individual factors like oral hygiene compliance and diet. Lesions can begin to form quickly, sometimes within just four weeks of the appliances being placed. The maxillary front teeth, particularly the lateral incisors and canines, are often the most susceptible areas to demineralization.
Proactive Measures to Avoid Demineralization
Preventing white spot lesions requires a diligent oral hygiene routine throughout orthodontic treatment. Brushing needs to be performed after every meal, or at least twice daily, for two minutes each time. Patients must angle the toothbrush bristles both above and below the brackets to effectively clean the tooth surface and gumline.
Specialized tools are necessary to reach the areas inaccessible to a standard toothbrush. Interdental brushes, which feature small bristles on a wire, are effective for cleaning under the archwire and around the individual brackets. Flossing, which is crucial for removing plaque between teeth, can be accomplished using floss threaders or specialized orthodontic floss to navigate the wire.
The regular application of fluoride is a major defense against demineralization because it promotes remineralization. For patients considered at high risk, a dental professional may prescribe a high-concentration fluoride toothpaste, often containing 5,000 parts per million (ppm) fluoride, for daily use. Professional fluoride treatments, such as a 5% sodium fluoride varnish, are often applied directly to the enamel around the brackets during routine orthodontic appointments.
Modifying one’s diet minimizes the acid challenge to the enamel. It is advisable to limit the intake of highly acidic beverages, such as sodas, sports drinks, and fruit juices, which accelerate mineral loss. Reducing the frequency of consuming sugary and fermentable carbohydrate-rich foods limits the fuel available for acid-producing bacteria.
Calcium phosphate products, such as those containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), can be used in conjunction with fluoride. These products release calcium and phosphate ions that help repair the porous enamel structure. Regular dental and orthodontic visits allow the provider to monitor enamel health and apply professional preventive treatments as needed.
Clinical and At-Home Options for Existing Spots
Once white spots are present after the braces are removed, the first course of action is a conservative, at-home approach focused on remineralization. Minor lesions may fade naturally over several months as the tooth surface is exposed to saliva, which contains calcium and phosphate ions. Daily use of high-concentration fluoride products and calcium phosphate pastes helps accelerate this natural repair process. If the spots persist and are a cosmetic concern, minimally invasive clinical procedures are available.
Enamel Microabrasion
Enamel microabrasion involves the application of a paste containing a mild acid, such as hydrochloric acid, combined with an abrasive agent like pumice. This mixture is polished onto the tooth surface, removing a microscopic layer of the outermost, stained enamel. Microabrasion is most effective for shallow, superficial lesions.
Resin Infiltration
For deeper, non-cavitated lesions, resin infiltration is a highly effective, non-restorative treatment. This technique uses a low-viscosity resin to penetrate the porous, demineralized enamel. The process begins with applying a mild acid to open the pores, followed by a drying agent to prepare the internal structure.
The resin soaks into the microscopic pore system within the enamel, replacing the air and water that cause the white appearance. Because the resin’s light-refracting properties match those of healthy enamel, it masks the white spot and makes the lesion visually disappear. This procedure reinforces the enamel structure and provides a physical barrier against future acid attacks, all without requiring drilling or anesthesia.
Restorative options are reserved for the most severe cases where the lesion has progressed to a cavity or where non-invasive methods have been unsuccessful. These typically involve dental bonding using tooth-colored resin or, in rare instances, the placement of porcelain veneers to cover the affected tooth surface. These interventions are more invasive as they require removing some natural tooth structure.