**White-Spot Lesions in Orthodontics: Incidence and Prevention**

Airton O. Arruda, Scott M. Behnan and Amy Richter *University of Michigan, USA* 

#### **1. Introduction**

312 Contemporary Approach to Dental Caries

Zijp, J.R. & Bosch, J.J. (1993). Theoretical model for the scattering of light by dentin and

The most common negative effect of orthodontic treatment with fixed appliances is the development of incipient carious lesions around brackets. The objectives of this chapter are to present some of the results of two studies aiming: 1) to evaluate patients treated with comprehensive orthodontics to determine the incidence of new carious lesions during treatment; and 2) to investigate the potential of ACP-containing resin cement and other treatments (fluoride varnish, resin sealer, MI Paste) to prevent incipient carious lesions on bracketed teeth. In the first study, 350 orthodontic patients were selected randomly. The preand post-treatment photographs of the patients were examined to determine lesion development. The labial surface of each tooth was scored with a standardized system based on the *International Caries Determination and Assessment System II*. The independent variables were collected by chart abstraction. In the second study, 100 extracted human premolars were allocated randomly to five groups (N = 20). Brackets were bonded with ACP-cement (Aegis-Ortho), Transbond

XT (Control), Transbond XT followed by application of fluoride varnish (Vanish), resin sealer (Pro-seal) and CPP-ACP paste (MI Paste). All teeth were pH cycled for 15 days in demineralization solution and artificial saliva. The extent of demineralization in each group was assessed using Quantified Light-induced Fluorescence (QLF) and Confocal Laser Scanning Microscopy (CLSM). The incidence of patients who developed at least one new white-spot lesion during treatment was 73%. Treatment length was associated significantly with new white-spot lesion development. The independent variables of gender, age and extraction/non-extraction were not associated with lesion development. Fluorescence loss and lesion depth measurements demonstrated that the Pro-seal and Vanish groups had the least amount of demineralization. The control group showed the most demineralization. Although the MI Paste and Aegis-Ortho groups experienced less demineralization than controls, neither was significant statistically. Only the Pro-seal and Vanish groups had significantly smaller lesions than the control group for both QLF and CLSM. Thus, the development of new lesions appeared to be related to treatment duration and, to a lesser degree, to initial oral hygiene score. Light-cured filled sealer (Pro-seal) and the fluoride varnish (Vanish) have the potential to prevent enamel demineralization adjacent to orthodontic brackets exposed to cariogenic conditions.

White-Spot Lesions in Orthodontics: Incidence and Prevention 315

orthodontic treatment, these unesthetic spots tend to remain unless they are resolved with more aggressive treatment, such as minimally invasive or even full restorative dentistry

The first line of defense against the development of incipient caries lesions has traditionally been patient education, with a special emphasis on optimal oral hygiene. The advocacy organization for orthodontists in the United States known as the American Association of Orthodontists (AAO) has developed patient manuals and a website to provide recommendations for patients undergoing orthodontic treatment (AAO, 2009). Specifically, the website suggests extra time for toothbrushing, specialized tips to get in between the braces, floss threaders, oral irrigators, and over-the-counter mouthrinses. Additionally, the AAO sponsored informed consent form emphasizes the need for excellent oral hygiene and routine visits to the general dentist (AAO, 2005). It also warns that inadequate oral hygiene could result in caries, discolored teeth, and periodontal disease. Finally, the form explains that the aforementioned problems may be aggravated if the patient has not had the benefit of fluoridated water. In many cases, patient education will also include an emphasis on proper diet with reduced intake of sugars. Despite these efforts by the orthodontist and staff members, many patients will still be non-compliant with oral hygiene instructions. Unfortunately, most orthodontists have a limited background in the behavioral basis of compliance (Mehra *et al.,* 1998). Thus, patient non-compliance presents a unique challenge to

In addition to reinforced oral hygiene instructions, orthodontists have turned to various products and preventive measures to reduce this problem. Dental professionals have employed fluoride for years to prevent caries and remineralize enamel in patients. A systematic review found a reduced level of caries and adolescents who have regular supervised rinsing with a fluoride mouthwash (Marinho, 2004). Daily fluoride rinses have shown promising results, and a significant reduction in enamel lesions can be achieved during orthodontic therapy through the daily use of a 10 mL neutral 0.05% sodium fluoride rinse. However, typical patient compliance rates with this protocol have been relatively low

Preventive measures that do not require patient compliance would seem to make more sense for the typical orthodontic patient population of adolescents. For some patients, professional fluoride varnish application by orthodontic auxiliaries at routine appointments can in part address this compliance issue (Vivaldi-Rodrigues *et al*., 2006). On the other hand, each application requires over five minutes of chair-time, and whether or not today's high efficiency/high volume orthodontic practice will devote the time and resources to apply this protocol is debatable. Generally however, fluoride varnishes have a proven track record in caries reduction when applied properly. Vanish (3M/Omni) is a very popular 5% NaF white

(Øgaard, 1989; Årtun and Thylstrup, 1989).

**3.1 Oral hygiene** 

orthodontic practices.

(Geiger *et al., 1992)*.

**3.3 Fluoride varnish** 

**3. Measures to counteract this problem** 

**3.2 Fluoride during orthodontic treatment (rinses, etc)** 
