How do we remineralize the demineralized areas efficiently?

White spot lesions are one of the most common sequel of orthodontic therapy. The most common
location for developing these lesions is on the gingival portion of the labial surface of the teeth. The
teeth most commonly affected are the maxillary lateral incisors and canines. Although minor WSLs
can remineralize post-treatment when exposed to fluoride and minerals, those that remain visible
pose esthetic problems for patients and potential medicolegal concerns for orthodontists. The most
widely used method used to prevent demineralization is the application of fluoridated products and
sealants onto the enamel surfaces. Fluoride prevents enamel demineralization and can remineralize
existing WSLs. Fluoride toothpaste and mouth rinse are problematic because each requires
compliance. Fluoride varnish and sealants provide longer lasting protective effects than toothpaste
or mouth rinse. Fluoride varnish and paints require reapplication frequently to be effective.

The following article is one such article that had compared the clinical efficacy of MI Varnish and
ProSeal sealant in preventing WSL formation in orthodontic patients.

“The efficacy of fluoride varnish vs a filled resin sealant for preventing white spot
lesions during orthodontic treatment: A randomized clinical trial”

Lauren N. Flynn, Katie Julien, Amal Noureldin, Peter H. Buschang. The efficacy of fluoride varnish vs a
filled resin sealant for preventing white spot lesions during orthodontic treatment: A randomized
clinical trial. Angle Orthod. 2022 Mar. doi: 10.2319/052521-418.1

What did this paper assess?

This paper compared the clinical efficacy of MI Varnish and ProSeal sealant in preventing WSL
formation in orthodontic patients and evaluated if it is more effective to regularly reapply ProSeal as
it wears away or to regularly reapply MI Varnish.

What was the protocol?

This study was a single-center, parallel, randomized clinical trial performed between October
2018 and March 2020. A total of 40 patients starting orthodontic treatment at Texas A&M
University College of Dentistry orthodontic department were selected based on the following
criteria: willingness to participate, no significant medical history, no underlying medical problems
requiring more than two medications (to prevent bias of possible dry mouth), younger than 17 years
of age at the start of orthodontic treatment, fully erupted and unrestored permanent maxillary
canines and incisors, starting fixed orthodontic treatment, and ability to come to appointments
every 4–6 weeks. Exclusion criteria included professional fluoride application in the past 3 months,
allergy to milk, untreated cavitated lesions, heavy initial fluorosis, dry mouth, pregnancy, and any
illness/condition that the investigators felt would affect the study outcome.

Block randomization of the patients was performed with Excel (Microsoft, Redmond, Wash) by
an investigator who had no clinical involvement in the trial. Patients were assigned to either Group
1, which had ProSeal applied to the facial surfaces of the maxillary anterior teeth and reapplied
every 3 months, or Group 2, which had MI Varnish applied to the maxillary anterior teeth every 4–6
weeks. Photographs were taken prior to initial bonding(T1). At the final appointment, the brackets,
composite, bonding agents, and sealants of both groups were removed and photos were taken (T2).

The patient photographs were randomized, and one blinded investigator performed all of the
assessments. The T1 and T2 photos were enlarged to corresponding sizes and compared side-by- side on a computer in a darkened room. The differentiation between a developmental enamel lesion and a decalcified WSL followed previous recommendations. The enamel decalcification index (EDI) score was also used to evaluate the axillary teeth.

EDI scores were summed for all six teeth at T1 and T2. Independent-sample t-tests were used to
evaluate differences between the two groups for oral hygiene scores and overall EDI sums. Paired t-
tests were used to evaluate differences between teeth as well as differences between tooth regions.
The chi-square test was used to determine differences in WSL prevalence, incidence, and differences
in EDI scores between different teeth and regions.

What did their results show?
Approximately 43% of patients and 15% of teeth developed WSLs during the study. The EDI
scores increased significantly, from 36 (T1) to 74 (T2). There was no statistically significant difference
between boys and girls in the incidence of WSL formation (P =0 .822). Based on the percentage of
teeth (9.5%) and percentage of patients (32.5%), the lateral incisors showed a significantly higher
incidence of WSL formation than the central incisors and canines. The lateral incisors also had the
greatest increase of EDI scores over time. Based on the percentages of teeth (10.4%) and patients
(32.5%), the incidence of WSL formation was significantly greater in the gingival than in the mesial,
distal, or incisal regions. The gingival region also showed the greatest increase of EDI scores over
time. Poor oral hygiene at T2 showed a high positive predictive value (76%) for the development
of WSLs.

Critical appraisal :.

The efforts of the authors to take pre and post treatment photographs is appreciable. But it would
have also been good to have a clinical examination done and compared it to the photograph as there
could have been light effects from the camera masking or exaggerating the existence of WSLs
immediately after debonding. Thus the reliability of the results is questionable. Also the results were
also based on the patient’s ability to maintain the oral hygiene. Moreover, as they had mentioned,
they did not allow enough time for the teeth to remineralize post debonding which would have had
a significant reduction in the rate of incidence of WSLs. Also they had failed to record the prevalence
of WSLs pre-treatment which could have been a contribution to the higher incidence of WSLs post
debonding.

What we would have liked to know?

Considering the purpose of the study, evaluation of the efficiency of MI varnish with and without
reapplication or reapplication at different time points would have contributed more on the
knowledge of use of MI varnish.

Conclusion and scope for future studies :

The study showed that lateral incisors are more likely to develop WSLs than canines and central
incisors. The gingival region is more likely to develop WSLs than other regions of teeth. Patients who
develop WSLs have poorer oral hygiene. The study also emphasized that when regularly reapplied,
MI Varnish and ProSeal sealant provide similar levels of protection during orthodontic treatment,
although varnish may be simpler to apply/reapply.
Future studies with different reapplication times and more number of samples could give a
conclusion on how to put varnish/sealant to the best of its use in preventing the WSL.
Contributors : Dr. Chandnee Shri, Dr. Bhadrinath