Effect of enamel deproteinization on bonding orthodontic brackets: A systematic review and meta-analysis

Abstract

Background: Frequent deboning is common during orthodontic treatment. Enamel deproteinization with 5.25% NaOCl or papain has been proposed as one way to increase shear bond strength (SBS) of orthodontic brackets. Moreover, frequent appearance of white spot lesions is common yet unwanted consequence of orthodontic treatment. The use of fluoride releasing resin modified glass ionomer cements (RMGIC) as an adhesive for bonding has been proposed to help minimize white spot lesions. However, with their reduced SBS compared to resin composite, the use of RMGIC, clinically, is not highly recommended. Enamel deproteinization has been proposed as one way to increase SBS of RMGIC. Aim: to systematically review studies assessing the effect of enamel deproteinization on SBS and adhesive remnant index (ARI) of orthodontic brackets by a systematic review of the published literature

Materials and Methods: Unrestricted electronic search of 5 databases and grey literature was performed. Following the preferred reporting items for systematic reviews and meta-analysis (PRISMA) statement, randomized trials using extracted human premolar teeth with intact buccal surface, no cracks, no pretreatment with chemical agents, no caries and absence of congenital or developmental conditions with at least one group using deproteinization with 5.25%NaOCl or Papain as an additional measure while bonding were included to assess the effect of deproteinization on SBS as the main outcome and on ARI as a secondary outcome . The random effect method of combining treatment effects for different groups was used. Risk of bias assessment was performed using the Cochrane’s collaboration tool risk of bias tool for randomized trials. Study selection, risk of bias assessment, and data-extraction were performed in duplicate.

Results: 19 studies met the inclusion criteria and were included in this systematic review; 14 studies were included the meta-analysis. Eleven studies were at high risk of bias and 4 were at unclear risk. Very low evidence shows that 5.25%NaOCl improved the SBS 0.7(-1.86-0.47). P=0.24 and ARI 0.55 (-0.52 – 1.63) P=0.3 of brackets bonded with RMGIC to be comparable with resin composite only. However, with significantly high heterogeneity for SBS (I 2 , 90%; P <0.00 1) and ARI (I 2 , 86%; P ) respectively. Moreover, for the other comparisons, when comparing 5.25%NaOCl with resin composite to resin composite only, no improvement in SBS 0.212 MPa (-0.16- 0.6), P=0.27 nor ARI 0.14(-0.3-0.56), P=0.5was shown. Similarly, when comparing 5.25%NaOCl RMGIC to RMGIC only, no improvement in SBS 0.36MPa (-0.19-0.89), P=0.2 nor ARI 0.54 (- 0.5-0.1.62), P=0.312was shown. With regards to pretreatment with 10%Papain, a significant mean difference favoring the control group was shown for SBS 0.95MPa (0.63 – 1.26) P 0.001 and ARI 0.55 (0.23- 0.87), P<0.05.

Conclusion: There is no strong evidence that enamel deproteinization improves SBS and ARI of orthodontic brackets bonded with resin composite or RMGIC.