**11.2 Demineralization protocol**

324 Contemporary Approach to Dental Caries

The overall incidence of patients who developed at least one WSL during orthodontic treatment was 72.9% (N = 255; Table 1 and Fig. 3), while for newly developed cavitated lesions that were unrestored on the final record was 2.3%. Of the eight patients that developed cavitated lesions during orthodontic treatment, four (1.1%) developed one new cavitated lesion, three (0.9%) developed two new cavitated lesions and one (0.3%) developed four new cavitated lesions. Of the maximum 24 surfaces investigated per patient, on average 4.2 surfaces in each patient showed new WSL. The average of surfaces with new cavitations was only 0.04 and 0.05 with restorations. Even though infrequently, some early WSL regressed to sound (0.07 per patient). Demographic variables of gender and age at initiation of treatment were not related significantly to development of new decalcified or cavitated lesions. There was a significant relationship between increased treatment length and number of newly developed lesions (*P* = 0.03; Table 2). The mean number of labial surfaces per patient that developed new WSL was 3.01 for patients with a treatment length of less than 22 months. This increased to 5.28 teeth for patients with therapy longer than 33 months. The number of new cavitations, however, showed only a nonsignificant trend (*P* = 0.08) with increased treatment time. In addition, the number of newly developed lesions (both WSL and cavitations) showed no significant association with extraction or nonextraction treatment protocols (Table 3). Although no relationship was demonstrated between pretreatment oral hygiene scores and lesion development, the recorded number of oral hygiene discussions between provider and patient were associated significantly with development of both white-spot (*P* <0.0001) and cavitated (*P* = 0.0006) lesions. The mean number of new lesions for patients with whom oral hygiene discussions had never been noted in the chart was 3.08, while the mean number of decalcified lesions for patients who were given oral hygiene instruction on three or more occasions increased to 7.78. A similar increase was exhibited for the mean number of cavitated lesions for patients given three or more oral hygiene discussions (mean = 0.20) *vs.* those with whom oral hygiene was not discussed after initial instruction (mean = 0.01). Age group (*P* = 0.03), treatment length (*P* = 0.01) and number of oral hygiene discussions (*P* < 0.0001) were associated with development of WSL. There was a decrease in WSLs associated with increasing age group (regression coefficient = -0.59). An increase in WSLs was associated with both increased treatment time (regression coefficient = 0.07) and increased number of oral hygiene

One hundred human premolar teeth were collected from various oral surgery practices located in southeast Michigan. Only premolars presenting a healthy facial enamel surface were included. All teeth were assigned randomly to five equal groups of 20 teeth. One of the groups had brackets bonded with Aegis-Ortho resin cement while the remaining groups were bonded with Transbond XT. Of the four Transbond XT groups, one served as a control, another received Vanish (3M, Espe, MN) fluoride varnish, another received MI Paste and

**10. Results: Part I** 

discussions (regression coefficient = 1.88).

**11. Methods and materials: Part II** 

the final received a coat of Pro-seal as adjunctive treatments.

**11.1 Sample preparation** 

Teeth were exposed to a pH cycling system to develop caries-like lesions. Each day teeth were incubated in demineralization solution (lactic acid and Carbopol [pH = 5.0], 50% saturated with hydroxyapatite) for eight hours, rinsed with de-ionized water and placed in artificial saliva for 30 minutes, followed by two seconds of brushing with a powerbrush (Sonicare, Philips) and fluoridated dentifrice (NaF, 1,100 ppm F), rinsed again and placed back in artificial saliva until next demineralization period (next day).


Table 1. Incidence of white-spot lesions (WSLs)

Solutions were refreshed daily during the experimental period of 15 days. On day 15, all teeth were removed from the saliva solution, rinsed under tap water and stored in 100% humidity. To assess demineralization, Quantitative Light-induced Fluorescence (QLF) and Confocal Laser Scanning Microscopy (CLSM) were used. Both procedures were carried out at the Oral Health Research Institute (IU) in Indianapolis, IN.

White-Spot Lesions in Orthodontics: Incidence and Prevention 327

Demineralization assessed by QLF is shown in Table 4. The Proseal group had the least amount of fluorescence loss followed by the Vanish group. Aegis-Ortho group, MI Paste group and the control group (Transbond) had the most fluorescence loss and were not different significantly. Demineralization assessed by CLSM is shown in Table 5. No detectable lesion depth was seen in any of the specimens of Pro-seal and Vanish groups. The greatest lesion depth was found in the control group (Transbond), but it was not different

The use of intraoral photographs for caries determination in orthodontic patients is a wellaccepted method. Standardized photographs taken before and after appliance placement are available readily as a standard procedure in orthodontic care. Color photography as a means of recording prevalence of enamel opacity is a powerful method (Ellwood, 1993). Studies have shown that assessment of enamel demineralization from color images appears to be more reproducible than direct clinical observation utilizing only the naked eye (Benson *et al.,* 1998). Moreover, photographic records provide an efficient means to capture the appearance of enamel and provide a permanent record at a given time point. It allows an examiner, therefore, to assess the caries experience of a patient blindly and randomly. Based on pre- and post-

**12. Results: Part II** 

significantly from Aegis-Ortho and MI Paste.

\*Groups not different significantly (*P*>0.05). *ΔF*=fluoresce loss.

\*Groups not different significantly (*P*>0.05). *ΔF*=lesion depth.

Table 5. Lesion depth for each group (N=20).

**13. Discussion** 

Table 4. Loss of fluorescence per group(N=20).


\*= *P*- value significant at *P*<0.005.

Table 2. Multivariabile regression model.


Table 3. Inferential statistics. Adjusted R-square = 0.11. This model accounts for 11% of the variation inWSL development.

Fig. 3. Distribution of patients with at least one new lesion.
