Microhardness, Structure, and Morphology of Primary Enamel after Phosphoric Acid, Self-Etching Adhesive, and Er:YAG Laser Etching

María Del Carmen Zoila Alcantara-Galeana,Rosalía Contreras-Bulnes,Adriana Fernández-Bobadilla,Manuel Eduardo Espinosa-Pesqueira,Laura Emma Rodríguez-Vilchis,Cecilia Carlota Barrera-Ortega,Itzel Monserrat López-Hurtado

doi:10.1155/2017/7634739

Abstract

Background. Phosphoric acid is the traditional etching agent; self-etching adhesives and Er:YAG laser are alternative methods. Knowledge of deciduous enamel etching is required.Aim. To evaluate primary enamel microhardness, structure, and morphology after phosphoric acid, self-etching, and Er:YAG laser etching.Design. Seventy primary incisors were assigned to five groups (n=14): I (control), II (35% phosphoric acid), III (self-etching adhesive), IV (Er:YAG laser at 15 J/cm2), and V (Er:YAG laser at 19.1 J/cm2). Microhardness was evaluated by Vickers indentation. Chemical composition was analyzed by energy dispersive X-ray spectroscopy and morphological changes by scanning electron microscopy. One-way ANOVA, Kruskal–Wallis, Mann–WhitneyU, and Pearson bivariate correlation were employed (α=0.05).Results. Vickers microhardness showed differences and no correlation with Ca/P ratio. Group II showed differences in carbon, oxygen, and phosphorus atomic percent and group V in Ca/P ratio. Morphological changes included exposed prisms, fractures, craters, and fusion.Conclusions. Enamel treated with phosphoric acid showed different chemical characterization among groups. Self-etching and Er:YAG laser irradiation at 19.1 J/cm2showed similar microhardness and chemical characterization. Er:YAG laser irradiation at 15 J/cm2maintained microhardness as untreated enamel. Er:YAG laser irradiation at 19.1 J/cm2enhanced mineral content. Morphological retentive changes were specific to each type of etching protocol.

Highlights

The adhesion to enamel produced by phosphoric acid etching has been considered strong and highly durable, the value of this technique in recent years has taken a secondary position with the introduction of self-etching adhesive systems as alternative methods [1, 2]
Studies evaluating self-etching adhesives disagree on the efficacy of etching because morphological analyses of enamel surface treated with self-etching primers have shown surfaces that are not very demineralized and unetched areas [2]
This study aimed to evaluate the microhardness, structure, and morphology of the primary enamel surface after etching with phosphoric acid, self-etching adhesive, and Er:YAG laser irradiation

Summary

Introduction

The adhesion to enamel produced by phosphoric acid etching has been considered strong and highly durable, the value of this technique in recent years has taken a secondary position with the introduction of self-etching adhesive systems as alternative methods [1, 2]. Phosphoric acid is the traditional etching agent; self-etching adhesives and Er:YAG laser are alternative methods. Aim. To evaluate primary enamel microhardness, structure, and morphology after phosphoric acid, self-etching, and Er:YAG laser etching. Seventy primary incisors were assigned to five groups (n = 14): I (control), II (35% phosphoric acid), III (self-etching adhesive), IV (Er:YAG laser at 15 J/cm2), and V (Er:YAG laser at 19.1 J/cm). Enamel treated with phosphoric acid showed different chemical characterization among groups. Self-etching and Er:YAG laser irradiation at 19.1 J/cm showed similar microhardness and chemical characterization. Morphological retentive changes were specific to each type of etching protocol

Objectives

Methods

Results

Discussion

Conclusion