# Minimally Invasive Dentistry for Pre-Eruptive Enamel Lesions--A Case Series
## 4 Discussion  
One of the biggest challenges dental clinicians face is the resolution of unesthetic enamel defects, which may vary in etiology, color, extension, and depth. Hypomineralization is the common feature to all white enamel defects, which include white spot carious lesions, dental fluorosis, traumatic hypomineralization, and molar incisor hypomineralization, and different treatment approaches might be used to improve the esthetic appearance of these lesions [1], which is of utter importance since these enamel defects present an optical problem due to their higher pore volume [2,3]. It is important to have a proper differential diagnosis based on clinical appearance, localization, and extension of lesions, and a detailed medical and dental history to select the best treatment for each case. For WSLs, post-eruptive enamel defects, the recommended treatments are mineralization [1,4,11,12], microabrasion [6,11,13,14,15], and/or resin infiltration [1,4,6,11,12,14,16]. These are all valid treatment approaches; however, remineralizing agents, such as fluorides, suffer from very superficial effects and high pH-dependency [17]. When it comes to fluorosis and traumatic hypomineralization lesions, even though they differ in clinical aspects, the treatment approaches are similar since they include microabrasion associated, or not, with dental bleaching [1,6,15], and resin infiltration may also be a possibility [1,6]. Molar-incisor hypomineralization, however, unlike other enamel defects, starts from the dental-enamel junction and not the enamel subsurface [1]. In severe cases, microabrasion or resin infiltration may be attempted to attenuate the appearance [1,6], but in mild cases, no treatment is recommended since microabrasion and other techniques would require the removal of two thirds of sound enamel [1]. Microabrasion is a safe, practical, and quick technique and is used nowadays by a great number of clinicians to manage enamel defects. It is a minimally invasive treatment approach, it does not require local anesthesia, and it allows good esthetic results with no significant postoperative sensitivity [15].This technique has evolved throughout the years and several studies have shown the importance of the combined use of abrasive and erosive actions. Not only is the abrasive component important to neutralize the erosive action of the acids, but the use of pumice alone is insufficient to remove the outer enamel layer [7]. Opalustre(r) (Ultradent Products, Inc.), which was used in the all the clinical cases, is a premixed slurry of 6.6% hydrochloric acid and silicon carbide microparticles. Its main advantage over other products is that, being a premixed slurry, it is more easily applied. According to some authors, other alternatives include using phosphoric acid at 35-37.5% and pumice, individually or by mixing them before application [7,15]. Due to the caustic and toxic effects of the hydrochloric acid component of the Opalustre(r) product (Ultradent Products, Inc.) [18], it is important to assure proper isolation, which was why in all the cases a rubber dam was used. However, with the use of the rubber dam, teeth become much more dry, and will need time to rehydrate, since the air that replaces the organic fluids when teeth become drier has a lower refractive index (\(\text{RI}_{\text{air}}\approx 1<\text{RI}_{\text{organic fluids}}=1.33\)), and the difference between healthy enamel (\(\text{RI}_{\text{hydroxapatite}}=1.62\)) and the enamel  
Figure 4: Case 3 diagnosed with traumatic hypomineralization. (**A**): Preoperative photograph with rubber isolation with floss ligatures showing a white enamel defect on tooth 11. (**B**): Immediate postoperative photograph. defects becomes more obvious, which is why it is necessary to reevaluate the results at a second appointment [1].