aesthetics is a primary concern among young patients and represents a challenge to the 
 dentist . many attractive smiles are marred by some discoloration or staining , either on an 
 individual tooth or on all teeth . isolated yellow , brown , or white areas on an otherwise 
 normal enamel surface , though , are common . improved materials and techniques have been developed 
 to remove or mask discoloration to solve these unaesthetic conditions . such exogenous stains may be of extrinsic etiology , for example , those caused by food 
 dyes ( coffee , tea ) or tobacco use , or accumulation of plaque and dental calculus , or 
 intrinsic etiology , which can be congenital or acquired . dentinogenesis imperfecta and dental fluorosis are 
 considered congenital intrinsic stains ; tetracycline dentin staining or injuries are 
 considered acquired intrinsic staining that may be related to the stages of pre or post 
 eruption . any of these terms are 
 consequences of some abnormality in the formation of the inorganic component of the 
 enamel during amelogenesis . proposed treatments , depending on the severity of the enamel stains , range from invasive ceramic veneer 
 bonding restorations to abrasive chemical treatments . although aesthetic demands for 
 perfect smiles are increasing , economic problems have also influenced the patients ' 
 decisions among the treatment options . more conservative approaches based on cheaper and 
 less time - consuming treatments such as bleaching , micro - abrasive treatments and 
 composite resin restorations are widely used . enamel microabrasion is a conservative method for removing enamel to improve 
 discolorations limited to the outer enamel layer . ( 2007 ) noted in an in 
 vitro study that the enamel microabrasion technique results in a loss of 
 enamel of around 25 to 200 m , depending on the number of applications and acids 
 concentration . the use of various acids to remove enamel stains was described early , in 
 1916 . since then the enamel microabrasion technique has 
 been suggested for aesthetic improvements , employing a mixture of 18% hydrochloric acid 
 and pumice or 6.6% and 10% hydrochloric acid with silica carbide 
 particles , or even 37% phosphoric acid gel associated with extra fine grain pumice in proportions of equal 
 volume . the aim of this article was to describe and discuss the treatment of patients with 
 enamel stains . in addition , three case reports treated by enamel microabrasion were 
 presented after 11 , 20 and 23 years of follow - ups . a teenage girl had idiopathic white enamel demineralization of her maxillary 
 central incisors ( figure 1a ) . the enamel 
 microabrasion procedures were performed after enamel macroabrasion of the affected 
 enamel surfaces , using a fine - tapered diamond bur ( 3195 ff , kg sorensen indstria e 
 comrcio ltda , barueri , sp , brazil ) under water and air cooling ( figure 1b ) . rubber dam isolation was applied and the dental enamel 
 surface was treated with an application of the microabrasive product ( opalustre , 
 ultradent products inc , south jordan , ut , usa ) , three times on each of the three teeth 
 at 60-second intervals ( figure 1c , d and e ) . teeth 
 were polished with herjos f fluoridated prophylaxis paste ( vigodent coltene sa indstria 
 e comrcio ; rio de janeiro , rj , brasil ) . the immediate enamel aspects were satisfactory ( figure 1f and g ) . a : a teenage girl had idiopathic white enamel demineralization of her maxillary 
 central incisors ; b : after dental prophylaxis with pumice and water , a 
 fine - tapered diamond bur was used with water cooling to remove the superficial 
 layer of the stained enamel ; c : before treatment , the patient received eyeglasses 
 for protection and the teeth were isolated with a rubber dam ; d and e : opalustre 
 microabrasive product was applied and compressed upon the enamel surfaces , using a 
 rubber cup manufactured with enclosed brush bristles specifically developed for 
 this purpose . the microabrasion  slurry  was applied with high torque , but very 
 slow speed , to prevent splattering . the compound was applied three times on each 
 of the three teeth for intervals of 60 seconds . the teeth were rinsed with 
 water / air spray after each application ; f : the teeth were then dried with an air 
 syringe and polished with fluoridated prophylaxis paste . a 2% neutral - ph sodium 
 fluoride gel was applied to the treated enamel surfaces and left in place for 4 
 minutes ; g : the treated incisors are shown immediately after enamel 
 microabrasion the long - term follow - ups after the enamel microabrasion technique are presented in figures 2 , 3 
 and 4 . figure 
 2a presents a 12-year - old girl with idiopathic white enamel demineralization 
 of both the maxillary and mandibular teeth . eleven 
 years from the conclusion of the enamel microabrasion treatment , a new follow - up 
 appointment was scheduled ( figure 2b ) . it could be 
 noted that the microabraded teeth present a regular , smooth , and lustrous glass - like 
 enamel surface . the worn mesial and incisal surfaces of the maxillary central incisors 
 were reconstructed with composite resin ( tph , dentsply / caulk , milford , de , usa ) . a : a 12-year - old girl had idiopathic white enamel demineralization of both the 
 maxillary and mandibular teeth ; b : the teeth are shown eleven years after the 
 enamel microabrasion . the worn mesial and incisal surfaces of the maxillary 
 central incisors were reconstructed with composite resin , shades a1 and a2 a : a 9-year - old boy with white enamel demineralization staining of six incisors ; 
 b : twenty years after removal of the white stains on the maxillary central 
 incisors by application of 18% hydrochloric acid and pumice ; and after removal of 
 white stains located on the mandibular teeth by application of the prema compound . the right mandibular lateral incisor presented a deep white stain ; it was restored 
 with resin - based composite a : post - orthodontic white enamel stain of hard texture seen in a young patient ; b : 
 23 years after the removal of stains using 18% hydrochloric acid / pumice and dental 
 bleaching with 15% carbamide peroxide figures 3 and 4 present the 20 and 23 year follow - ups , respectively . figure 3a shows a 9-year - old boy with white stains located only on 
 the dental enamel in the maxillary and mandibular teeth . stains on the maxillary 
 incisors were removed by the enamel microabrasion technique with an application of 18% 
 hydrochloric acid and pumice . stains on the mandibular teeth were removed with an 
 application of the enamel microabrasion product prema compound ( premier dental products 
 co , norristown , pa , usa ) . the right mandibular lateral incisor presented a deep white 
 stain ; it was restored with resin - based composite ( prisma fill , dentsply / caulk , milford , 
 de , usa ) . figure 3b shows 20 years after the 
 removal of white stains , showing long - term satisfactory results . figure 4a shows a post - orthodontic white enamel stain of hard 
 texture seen in a young patient . the removal of stains was performed by the enamel 
 microabrasion technique using 18% hydrochloric acid / pumice and dental bleaching with 15% 
 carbamide peroxide ( opalescence , ultradent products inc , south jordan , ut , usa ) . however , in some cases the enamel defect can not be resolved with microabrasion because 
 it penetrates deeper into the enamel ( or perhaps even includes the dentin ) , and a 
 resin - based composite restoration can be accomplished . a teenage boy had deep white 
 enamel stains on the maxillary central incisors ( figure 
 5a ) . tooth preparation for resin - based composite was performed ( figure 5b and c ) . the teeth were etched for 30 seconds with 35% phosphoric acid 
 ( scotchbond(tm ) etchant , 3 m dental products division , st . paul , mn , usa ) , figure 5d . after water rinsing and air drying , a 
 two - step bonding agent was applied ( peak lc bond , ultradent products , inc . , south 
 jordan , ut , usa ) . resin composite restorations were then performed ( vitalescence , 
 ultradent products , inc . , south complete photo - polymerization was accomplished using a 
 light beam of 1000 mw / cm ( ultralux , dabi atlante , ribeiro preto , sp , 
 brazil ) , as seen in figure 5f . finishing and 
 polishing were completed using high speed diamond burs ( 1190f , kg sorensen indstria e 
 comrcio ltda , barueri , sp , brazil ) and low speed points ( # 850 - jiffy regular brushes 
 10pk ) ( jiffy brushes , ultradent products , inc . , south jordan , usa ) , as seen in figure 5 g . a : a teenage boy had deep white enamel stains on the maxillary central incisors ; 
 b : removal of the remainder of the abnormal white enamel with a fine - tapered 
 diamond bur ; c : tooth preparation for composite resin ; d : etching for 30 seconds 
 with 35% phosphoric acid ; e : after water rinsing and air drying , a two - step 
 bonding agent was applied . resin - based composite restoration was performed ; f : 
 complete photo - polymerization was accomplished using a light beam of 1000 mw / cm ; 
 g : finishing and polishing were completed using high speed diamond burs and low 
 speed points a method that can be used for trying to see how deep the white spot is in the enamel is 
 to put a halogen or led source on the palatal surface and turn it on . if the spot shows 
 its contour and darkens , it may be a deep white spot ( figure 6 ) . plus , the stains are located on the mid / incisal third , a critical 
 region . facing this , the patient must be alerted that microabrasion itself probably 
 might not remove the stains and restorative procedures may be necessary . a : patient with white spots ; b : a method that can be used to try to see how deep 
 the white spot in the enamel is to apply a led source on the palatal surface and 
 turn it on in some cases , there are some difficulties when diagnosing the etiology of the intrinsic 
 enamel stains . when a child ingests excessive amounts of fluoride during the years of 
 amelogenesis , superficial layers of enamel can acquire brown or white chromatic 
 alterations . a diagnostic quandary occurs when such stains are 
 evident , but no history of excessive fluoride ingestion is reported , or possible to be 
 verified . fluoride is not the only cause of superficial enamel discoloration defects , 
 even though many dentists use " fluorosis " as an all - encompassing description . some 
 stains can be termed " idiopathic enamel demineralization " or 
 " fluorosis - like " . clinical 
 procedures are used to improve the aspect of the affected teeth , which include : dental 
 bleaching , enamel microabrasion , restorative correction by using tooth colored bonded 
 adhesive materials ( porcelain veneers , direct resin - based composite repair , or , in some 
 cases , a combination of procedures ) . it has been shown that enamel microabrasion using acidic / abrasive products gives 
 immediate and permanent aesthetic results , with insignificant and unrecognizable loss of 
 enamel . the only measure for success is whether the enamel 
 stain surface texture irregularity is confined to the outermost , superficial layer of 
 the enamel . in the teeth where there are difficulties in diagnosing 
 the depth of the intrinsic stains , it is possible to perform microabrasion with the idea 
 of achieving as much improvement as possible to be followed by other procedures , such 
 as : tooth bleaching or restoration with bonded materials . dental bleaching with carbamide peroxide or hydrogen 
 peroxide after enamel microabrasion has been suggested for some patients , since the 
 enamel microabrasion promotes microreduction of the enamel surface . microabrasioned teeth can develop a darker shade or yellowish 
 coloration after treatment because the remaining enamel surface is slightly thinner and 
 translucent , so the dentin appears more evident . it has been suggested to wait several 
 weeks after the completion of the microabrasion before bleaching , based on the idea that 
 such a delay will provide ample time for complete enamel surface remineralization with 
 accompanying optical improvement . ( 2013 ) to evaluate the penetration of hydrogen peroxide applied to 
 microabrasioned enamel , noting that this substrate was more susceptible to hydrogen 
 peroxide diffusion during in - office bleaching . the patients ' age is not a limiting factor for the enamel microabrasion technique , but 
 there may be difficulties when using the rubber dam on teeth that are not totally 
 erupted . of course , enamel microabrasion is never indicated when stains are located only 
 within the dentin , such as with dentinogenesis imperfecta or tetracycline discoloration . 
 in patients who have deficient lip sealing ( a clinical condition that excessively 
 hinders the formation of a moisturizing pellicle on the enamel , when unprotected by the 
 upper and lower lips ) , enamel microabrasion can be delayed or contraindicated , because 
 the enamel surfaces are abnormally dry , which makes demineralization stains more 
 apparent . the usual presence of saliva hydrates the enamel and masks such stains by the 
 different light refractions of the enamel surface . often , these stains are more 
 restricted to the incisal dental third , usually presenting a white opaque coloration and 
 always following the contour of the most common resting position of the upper and lower 
 lips of the patient . all of these characteristics are associated with a judicious 
 examination , and may feature deficient lip sealing . sundfeld , et al . , in 2007 , found that for the effective 
 disappearance of these stains , lip repositioning should be corrected in some cases . orthodontic , educative phonoaudiology techniques for lip or speech therapists may be 
 required to correct lip positioning before enamel microabrasion . however , there may be a correlation of deficient lip sealing with 
 some occlusal changes , requiring a more comprehensive and multidisciplinary evaluation . 
 in clinical cases of lower complexity , deficient lip sealing can be originated by a bad 
 habit constantly repeated by the patient . therefore , the treatment of the bad habit can be performed by psychomotor conduction , 
 repositioning the lips - the patient is instructed to do daily exercises during 
 mandibular rest , stimulating them to maintain contact between the upper and lower lips , 
 using a medal attached to a chain , so that the lips keep in touch for the longest period 
 of time possible , thereby , toning the muscle orbicularis of the lips . it is appropriate to consider that when facing a white stain with a hard texture , not so 
 evident on the enamel surface , instead of applying microabrasion , it can be camouflage 
 by performing dental bleaching with carbamide or hydrogen peroxide , which act in the 
 dentin tissue , making it lighter 
 ( figure 7 ) . it is important to note that after 
 performing dental bleaching on teeth with white stains , they seem more evident after 
 each session because of the dehydration , but after a couple of days they will be 
 rehydrated by the saliva and the stains will be masked . a : teenage girl , presented with white enamel stain on the maxillary and mandibular 
 teeth ; b : after tooth bleaching with 15% carbamide peroxide opalescence . in some 
 cases , when white stains are small and not prominent , dental bleaching alone using 
 carbamide peroxide or hydrogen peroxide in custom trays may lighten the underlying 
 dentin and enamel sufficiently to camouflage the stain , with no need for 
 microabrasion stains and surface irregularities present in the enamel have led researchers to develop 
 materials and techniques for their removal . ( 2007 ) proposed the 
 application of a mixture of 18% hydrochloric acid and pumice to try to remove stains 
 with an insignificant loss of enamel ( figure 8) . the treatment must be performed with a rubber dam in place , with the patient wearing 
 protective glasses . the mixture is applied with a wooden stick and firm finger pressure 
 for 5 seconds on the stained surface of the enamel , not surpassing a total of 15 
 applications . between each application , a : ground tooth section presenting 25 m enamel loss after 3 applications , of 15 
 seconds each , of a mixture of 18% hydrochloric acid and pumice ( 25x ) ; b : 23 m 
 after 4 applications , of a mixture of prema compound enamel microabrasive ; c : 42 
 m after 4 applications , of 1 minute each , of a mixture of 37% phosphoric acid 
 and pumice ; d : 80 m after , after 4 applications , of 1 minute each , of opalustre 
 enamel microabrasive . the depression in the enamel convexity ( w ) designates where 
 the microabrasion was performed . analyzed by polarized light microscope ; e : 
 enamel ; d : dentin ; w : wear trying to obtain an acid / abrasive product that is safer for the oral tissues , the 
 operator , the patient and for an easier application , microabrasive products were 
 developed with a low hydrochloric acid concentration with silicon carbide powder , such 
 as : opalustre ( ultradent products inc , south jordan , ut , usa ) , prema ( premier dental 
 products , plymouth meeting , pa , usa ) and rm ( fgm & dentscare ltda , joinville , sc , 
 brazil ) . ( 2011 ) suggested the application of 37% phosphoric acid gel associated with extra fine 
 grain pumice in proportions of equal volume in order to make this technique safer and 
 more practical . ( 2007 ) noted that an in vitro application of 
 opalustre resulted in enamel loss ranging from 25 to 200 m , corresponding to 1 and 10 
 applications of the product for one minute on each tooth ( figure 8) . it is important to mention that macroabrasion with a fine grit 
 tapered diamond bur can be used to reduce the time needed for the enamel microabrasion 
 technique . in general , in comparing the pre - treatment and the post - treatment control paired 
 analysis , the studies have shown that enamel microabrasion using different compounds is 
 effective in removing stains from the outermost layer of the enamel and improving the 
 appearance of the teeth . both phosphoric acid 
 ( h3po4)-pumice and ( hcl)-pumice compounds presented effectiveness 
 in treating different severities of dental fluorosis by using the microabrasion 
 technique , however , the mean treatment time with the hcl - pumice was significantly lower 
 than the one with h3po4-pumice . in addition , clinically , we have noted that stains are routinely 
 removed with unrecognizable alterations . it has also been observed that the teeth of patients subjected to enamel microabrasion 
 have a smooth , prism - free layer of enamel and a lustrous surface that increases over 
 time . this " abrosion effect " 
 ( abrasion plus erosion ) may be due to the compaction of minerals resulting from the 
 simultaneous erosive and abrasive action of the microabrasion compound on the dental 
 enamel . ( 2011 ) after evaluating different techniques , concluded that 
 microabrasion followed by polishing with diamond paste or fluoride prophylatic paste 
 provided higher hardness and better surface smoothness of the enamel . in 1997 , segura , et al . , through an in vitro 
 polarized microscopic study , showed that enamel after microabrasion technique is more 
 resistant to demineralization than untreated enamel surfaces . in addition , it was 
 observed that there is less colonization by streptococcusmutans on 
 microabraded enamel . in assessing stained teeth for enamel microabrasion , bleaching and resin - based composite 
 repair , it is necessary to consider that enamel thickness varies in different crown 
 regions ( figure 9 ) . this makes for more 
 translucency in the incisal third of an anterior tooth , and more opacity as further 
 moving toward the gingival margin . these considerations are important to be remembered 
 when evaluating how much residual enamel there will be after microabrasion , how the 
 tooth will look after bleaching , and what color matching concerns will exist if 
 resin - based composite repair is to be achieved a : incisal 
 third analyzed by polarized light microscope ( 25x ) ; b. digital image nikon d 300 
 c. cervical third analyzed by polarized light microscope ( 25x ) correct application of the microabrasion technique , complemented or not by the bleaching 
 or the use of composite resin , allowed for significant improvement in the appearance and 
 color uniformity of the teeth , restoring the patient 's self - esteem . based on these three 
 case reports with long - term follow - ups , it can be concluded that microabrasion was a 
 safe technique , providing favorable results in the patients ' smiles overtime .
superficial irregularities and certain intrinsic stains on the dental enamel surfaces 
 can be resolved by enamel microabrasion , however , treatment for such defects need to 
 be confined to the outermost regions of the enamel surface . dental bleaching and 
 resin - based composite repair 
 are also often useful for certain situations for tooth 
 color corrections . 
 this article presented and discussed the indications and 
 limitations of enamel microabrasion treatment . 
 three case reports treated by enamel 
 microabrasion were also presented after 11 , 20 and 23 years of follow - ups .