Title Pre-Treatment of Enamel With Fluoride Prior To Orthodontic Bracket Placement Can Lower The Shear Bond Strength
Clinical Question For a patient with comprehensive orthodontic treatment, will fluoride application prior to orthodontic bracket placement, as compared to no fluoride application, affect the bond strength?
Clinical Bottom Line Pre-treatment of enamel with fluoride prior to orthodontic bracket placement can lower the shear bond strength but has no effect on tensile bond strength. This is based on two studies on extracted teeth. These findings are important in preventing the number of de-bonded bracket emergencies. Pre-treatment of enamel with fluoride prior to placement of orthodontic brackets may not be an effective treatment option.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
26023648Chandulal/201590 non-carious human premolar teethLaboratory study
Key resultsThe study demonstrated a slight decrease of tensile bond strength in the APF (Acidulated phosphate fluoride) group, compared to the control. However, there was no statistically significant difference (p<0.05) in tensile bond strength of brackets with or without fluoride application.
23338263Leódido/201248 freshly extracted sound bovine incisorsLaboratory study
Key resultsPre-treating the enamel with 1.23% Acidulated Phosphate Fluoride and 5% Sodium Fluoride Varnish shows statistically significant (p<0.0001) reduction in the shear bond strength of orthodontic brackets, compared to Neutral Fluoride application and no fluoride application.
Evidence Search ("fluorides"[MeSH Terms] OR "fluorides"[All Fields] OR "fluoride"[All Fields]) AND Orthodontic[All Fields] AND Bond[All Fields] AND Strength[All Fields]
Comments on
The Evidence
The study by Chandulal examined 90 specimens, out of which 6 groups of 15 teeth were created. Each of the three experimental conditions (control, APF, and SnF2) was assigned to two groups. Thus each condition was tested twice. Scanning Electron Microscope was used to assess the surface of the teeth after each treatment. A Microtech Tensometer was used to measure the tensile bond strength. While they tried to replicate the true conditions of the oral cavity here, there was no mention of addressing temperature/moisture changes in the mouth. The Leódido study used the following selection criteria to find 48 sound bovine incisors: intact enamel, with no cracks and no prior use of chemical agents such as thymol, hydrogen peroxide, alcohol or formaldehyde. The specimens were stored in artificial saliva. Four groups of 12 specimens were created with treatment conditions including: Control, Neutral Fluoride, 1.23% acidulated phosphate fluoride gel, and 5% Fluoride Varnish. After each treatment the teeth were bathed in saliva. Once brackets were bonded, the teeth were stored in an incubator at 37°C for 24 hours. The shear bond strength was measured using a universal testing machine with 50 kg load. This study used bovine teeth which may not exactly correspond to the same chemical composition or shape of human teeth. Although this study tries to more accurately replicate the conditions in the oral cavity, a case-control study with real orthodontic patients may be more valid to test the bond strength of brackets after fluoride application. Also, different bonding agents may show different results, so further studies are needed to look at the effect of bond strength with different bonding agents.
Applicability The answer to this clinical question is valuable to both the orthodontist and the patient. While fluoride application may be beneficial in strengthening the enamel and preventing decalcification around the brackets, understanding its effects on bond strength is crucial in determining the effectiveness of such treatment. If application of fluorides such as 1.23% APF and 5% SFV lowers the shear bond strength of orthodontic brackets, it may not be an effective treatment option, as practitioners would likely have to replace a larger number of debonded brackets. This would be inefficient for both the practitioner and the patient, who would have to make constant emergency visits to replace debonded brackets.
Specialty (General Dentistry) (Orthodontics) (Pediatric Dentistry)
Keywords Fluoride, Orthodontic brackets, Bond strength
ID# 2932
Date of submission 10/15/2015
E-mail jebraeili@uthscsa.edu
Author Shadzi Jebraeili, DDS
Co-author(s) e-mail
Faculty mentor Ravikumar Anthony, BDS, MDS, MS
Faculty mentor e-mail Anthony@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available