Effect of BG Versus RI on the Depth of WSL

White spot lesions are an adverse result of orthodontic treatment caused by poor oral hygiene. It is difficult to maintain oral hygiene during fixed orthodontic treatment.White spot lesions are subsurface enamel porosities due to demineralization of enamel. They are basically the early stages of caries and has milky white appearance. WSLs are usually formed four weeks after bracket placement.There are various methods for the treatment of white spot lesions. The invasive methods include crowns or veneers and microabrasion. The non-invasive methods are remineralizing agents like topical fluoride, bioactive glass, GC Tooth Mousse and resin infiltration material (ICON). Fluoride compounds are one of the first therapies for WSL. Fluoride varnishes inhibit the demineralization process and promotes the remineralization of enamel. The fluoride varnish forms the calcium fluoride on enamel surface and prolong the contact between fluoride and enamel.Previous studies have shown promising results achieved by bioactive glass as compared to other remineralizing agents. Resin infiltration has been introduced recently and there are few studies on the treatment of WSLs. The rationale of the study is to compare the effects of bioactive glass and resin infiltration through scanning electron microscopy and microhardness, as there is limited research on this topic. The purpose of this study is to compare and evaluate the lesion depth of artificial white spot lesions before and after the treatment with sodium fluoride varnish, bioactive glass and resin infiltration (ICON). The null hypothesis is that there are no significant differences among the three groups for the treatment of white spot lesions.

• Bioactive Glass (NovaMin) (Other): A carbonated beverage (Coca Cola, Pakistan ltd) will be used for artificial white spot lesion formation. The pH of the beverage will be 4-4.5 at 37ºC. The teeth will be immersed in demineralization solution for 4 weeks before treatment. The solution will be changed every 48 hrs. to keep the pH constant. After demineralization specimens will be washed with distilled deionized water (DDW). The tooth will have a white spot lesion only on the buccal surface. A sufficient amount of 5% bioactive glass (Biomin F T/P) was applied on the tooth surface for three minutes using a tooth brush. The toothpaste remained on the surface for an additional 30 minutes.
• Resin Infiltration (ICON) (Other): A carbonated beverage (Coca Cola, Pakistan ltd) was used for artificial white spot lesion formation. The pH of the beverage was 4-4.5 at 37ºC. The teeth were be immersed in demineralization solution for 4 weeks before treatment. The solution was changed every 48 hrs. to keep the pH constant. After demineralization specimens were washed with distilled deionized water (DDW). The tooth would have a white spot lesion only on the buccal surface. Resin infiltration (ICON) infiltration will be applied according to manufacture as following: * Application of Icon Etch (15% HCL gel) for 2 minutes. * Water rinsing and air drying for 30 sec. * Application of Icon-dry (ethanol) for 30 sec. * Air drying * Application of Icon Infiltrant for 3 minutes. * Light curing for 40 seconds.
• Fluoride Toothpaste (Other): A carbonated beverage (Coca Cola, Pakistan ltd) was used for artificial white spot lesion formation. The pH of the beverage will be 4-4.5 at 37ºC. The teeth were immersed in demineralization solution for 4 weeks before treatment. The solution was changed every 48 hrs. to keep the pH constant. After demineralization specimens was washed with distilled deionized water (DDW). The tooth would have a white spot lesion only on the buccal surface. The teeth were cleaned and dried first. 5% Sodium fluoride (Enamelist) varnish was applied on tooth surface with disposable tooth brush. The varnish remained undisturbed on teeth for 4 hours.

Primary outcomes

• Scanning Electron Microscopy [4th week]: Changes in baseline lesion depth were assessed using scanning electron microscopy. Scanning electron microscopy is used to assess lesion depth before and after treatment with remineralizing agents. Lesion depth is measured in microns. Comparison is made by calculating the average depth of treated samples against untreated demineralized control samples.
• Vickers Microhardness Test [4th week]: Changes from baseline microhardness tests are used to measure changes in surface hardness before and after remineralization. Sound or artificially demineralized enamel (acid-etched or caries-like lesions) is tested first to set a control value. Agents like fluoride varnishes, CPP-ACP (Casein Phosphopeptide-Amorphous Calcium Phosphate), or bioactive glass are applied over cycles. The percentage surface hardness measures how much demineralized enamel is hardened after remineralization treatment relative to original healthy baseline.

Sex: All, ages: 15 Years to 35 Years, accepts healthy volunteers

Inclusion Criteria:

* Upper and lower premolars will be collected from patients undergoing extractions.

  * The teeth should be healthy with no carious lesions.
  * The crown and root morphology of teeth should be normal.
  * The extracted premolar teeth of patients should have no history of previous dental treatment.

Exclusion Criteria:

* • Fractured premolars due to any cause.

  * Loss of enamel due to parafunctional habits.
  * Presence of enamel anomalies (amelogenesis imperfecta, hypoplasia etc.).
  * Presence of stains, demineralization, decay, fluorosis and restorations

• Eckstein A, Helms HJ, Knosel M. Camouflage effects following resin infiltration of postorthodontic white-spot lesions in vivo: One-year follow-up. Angle Orthod. 2015 May;85(3):374-80. doi: 10.2319/050914-334.1. Epub 2014 Aug 15. PMID 25126675
• Shan D, He Y, Gao M, Liu H, Zhu Y, Liao L, Hadaegh F, Long H, Lai W. A comparison of resin infiltration and microabrasion for postorthodontic white spot lesion. Am J Orthod Dentofacial Orthop. 2021 Oct;160(4):516-522. doi: 10.1016/j.ajodo.2020.04.039. Epub 2021 Jul 31. PMID 34344556
• Meyer-Lueckel H, Paris S. Infiltration of natural caries lesions with experimental resins differing in penetration coefficients and ethanol addition. Caries Res. 2010;44(4):408-14. doi: 10.1159/000318223. Epub 2010 Aug 17. PMID 20714153
• Baeshen HA, Lingstrom P, Birkhed D. Effect of fluoridated chewing sticks (Miswaks) on white spot lesions in postorthodontic patients. Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):291-7. doi: 10.1016/j.ajodo.2010.04.034. PMID 21889073
• Hu H, Feng C, Jiang Z, Wang L, Shrestha S, Su X, Shu Y, Ge L, Lai W, Hua F, Long H. Effectiveness of remineralising agents in prevention and treatment of orthodontically induced white spot lesions: a protocol for a systematic review incorporating network meta-analysis. Syst Rev. 2019 Dec 29;8(1):339. doi: 10.1186/s13643-019-1253-8. PMID 31884975
• Kannan A, Padmanabhan S. Comparative evaluation of Icon(R) resin infiltration and Clinpro XT varnish on colour and fluorescence changes of white spot lesions: a randomized controlled trial. Prog Orthod. 2019 Jun 17;20(1):23. doi: 10.1186/s40510-019-0276-y. PMID 31204437

• Ulfat Bashir, MDS, Principal investigator, Riphah International University