Enamel Deproteinization and Its Effect on Acid Etching: An in vitro Study

Abstract

Purpose: The goal of this in vitro study was to identify the topographical features of the enamel surface deproteinized and etched with phosphoric acid (H3PO4) compared to phosphoric acid alone. Materials and method: Ten extracted lower first and second permanent molars were polished with pumice and water, and then divided into 4 equal buccal sections having similar physical and chemical properties. The enamel surfaces of each group were subjected to the following treatments: Group A: Acid Etching with H3PO4 37% for 15 seconds. Group AH1: Sodium Hypochlorite (NaOCl) 5.25% for 30 seconds followed by Acid Etching with H3PO4 37% for 15 seconds. Group AH2 ; Sodium Hypochlorite (NaOCl) 5.25% for 60 seconds followed by Acid Etching with H3PO4 37% for 15 seconds. Results showed that group AH2 etching technique reached an area of 76.6 mm2 of the total surface, with a 71.8 mm2 (94.47%), type 1 and 2 etching pattern, followed by group AH1 with 55.9 mm2 out of 75.12 mm2 (74.1%), and finally group A with only 36.8 mm2 (48.83%) out of an area of 72.7 mm2. A significant statistical difference (P <0 .05) existed between all groups, leading to the conclusion that enamel deproteinization with 5.25% NaOCl for 1 minute before H3PO4, etching increases the enamel conditioning surface as well as the quality of the etching pattern.

Assessment of shear bond strength and microleakage of fissure sealant following enamel deproteinization: An in vitro study

“…Acid etching with H 3 PO 4 does not necessarily result in a homogeneous and adequately etched surface, and this can lead to the eventual failure and loss of fissure sealant applications or restorations (12,18). The quantity and quality of etching are immensely important and depends on many factors such as the acid agent used, acid concentration, etching duration, and enamel surface composition (12). To increase etching quality and retention, both invasive and non-invasive techniques have been proposed and investigated.…”

“…Deproteinization removes the surface organic matter layer prior to acid etching, which aids in creating the desired type I or type II etching pattern. A portion of the organic residue present on the enamel surface consists of acid-insoluble proteins and the acquired pellicle, which can hinder effective acid etching (11,12). Sodium hypochlorite is an excellent protein denaturant (11).…”

“…Sodium hypochlorite is an excellent protein denaturant (11). Removal of excess proteins may enhance material adhesion to the tooth surface (12). The effects of enamel deproteinization using 5.25% sodium hypochlorite (NaOCl) prior to phosphoric acid (H 3 PO 4 ) on the etching patterns as well as on the shear bond strength have been investigated previously (11)(12)(13).…”

“…Removal of excess proteins may enhance material adhesion to the tooth surface (12). The effects of enamel deproteinization using 5.25% sodium hypochlorite (NaOCl) prior to phosphoric acid (H 3 PO 4 ) on the etching patterns as well as on the shear bond strength have been investigated previously (11)(12)(13). Espinosa et al (12) reported that enamel deproteinization with 5.25% NaOCl for one min before H 3 PO 4 etching improves the quality of enamel acid etching and therefore increases the enamel's retentive surface significantly.…”

“…The effects of enamel deproteinization using 5.25% sodium hypochlorite (NaOCl) prior to phosphoric acid (H 3 PO 4 ) on the etching patterns as well as on the shear bond strength have been investigated previously (11)(12)(13). Espinosa et al (12) reported that enamel deproteinization with 5.25% NaOCl for one min before H 3 PO 4 etching improves the quality of enamel acid etching and therefore increases the enamel's retentive surface significantly. In addition, Garrocho-Rangel et al (9) demonstrated that 5.25% NaOCl deproteinization prior to enamel etching resulted in lower rates of microleakage between the enamel surface and the fissure sealant material than conventional H 3 PO 4 etching alone.…”