Abst ract
Submitted: August 10, 2016 0RGL¿FDWLRQ2FWREHU Accepted: November 12, 2016
Crown discolorat ion prom ot ed by
m at erials used in regenerat ive
endodont ic procedures and effect of
dent al bleaching: spect rophot om et ric
analysis
Regenerat ive endodont ic procedure ( REP) has been proposed as a new approach t o t reat im m at ure perm anent t eet h. However, m at erials used in REP for root canal disinfect ion or cervical sealing m ay induce t oot h discolorat ion. Obj ect ives: To assess t oot h crow n’s color aft er int racanal t reat m ent w it h t r iple ant ibiot ic past e ( TAP) or calcium hydr ox ide ( CH) ; cer v ical sealing w it h glass ionom er cem ent ( GI C) or m ineral t r iox ide aggr egat e ( MTA) ; and bleaching w it h carbam ide peroxide. Mat erial and Met hods: Aft er pulp rem oval and color spect rophot om et er m easurem ent , 50 bovine incisors were divided int o 4 experim ent al groups and one cont rol ( unt reat ed) . Experim ent s ZHUH SHUIRUPHG LQ SKDVHV 3K 3K 7$3 FLSURÀR[DFLQ PHWURQLGD]ROH m i n ocy cl i n e) , TAPM ( ci p r of l ox aci n , m et r on i d azol e, am ox i ci l l i n ) , DAP FLSURÀR[DFLQPHWURQLGD]ROHRU&+WUHDWPHQWJURXSV$IWHUDQGGD\V ( d) ; 1, 2, 3 w eeks ( w ) ; and 1, 2, 3 and 4 m ont hs ( m ) , color was m easured and m edicat ions w ere rem oved. Ph2: GI C or MTA cervical sealing, each using half of t he specim ens from each group. Color was assessed aft er 1d, 3d; 1w, 2w, 3w ; 1m and 2m . Ph3: Two bleaching sessions, each follow ed by color m easurem ent . Dat a w ere analyzed w it h ANOVA and post hoc Holm -Sidak m et hod. Result s: Ph1: Specim ens of TAP group present ed higher color DOWHUDWLRQƩ(PHDQWKDQWKRVHRI7$30JURXS1RVLJQL¿FDQWGLIIHUHQFH was found am ong TAP or TAPM and CH, DAP or Cont rol groups. Ph2: cervical VHDOLQJPDWHULDOVVKRZHGQRLQÀXHQFHRQFRORUDOWHUDWLRQ3K'LIIHUHQWƩ( m eans ( from different groups) , prior t o bleaching, becam e equivalent aft er one bleaching session. Conclusions: TAP induces higher color alt erat ion t han TAPM; color alt erat ion increases over t im e; cervical sealing m at erial has no LQÀXHQFHRQFRORUDOWHUDWLRQDQGGHQWDOEOHDFKLQJZDVDEOHWRUHFRYHUDW least part ially, t he t oot h crown’s color.
Ke y w o r d s: Reg en er at iv e en d od on t ics. Sp ect r op h ot om et r y. Toot h discolorat ion. Triple ant ibiot ic past e. Dent al bleaching
Luciane Geanini Pena dos SANTOS1
Wilson Tadeu FELIPPE1
Beatriz Dulcineia Mendes de SOUZA1
Andrea Cristina KONRATH2
Mabel Mariela Rodríguez CORDEIRO3
Mara Cristina Santos FELIPPE1
http://dx.doi.org/10.1590/1678-77572016-0398
1Universidade Federal de Santa Catarina, Departamento de Odontologia, Florianópolis, Santa Catarina, Brasil.
2Universidade Federal de Santa Catarina, Departamento de Informática e Estatística, Florianópolis, Santa Catarina, Brasil.
3Universidade Federal de Santa Catarina, Departamento de Ciências Morfológicas, Florianópolis, Santa Catarina, Brasil.
I nt roduct ion
Regenerat ive endodont ic procedures ( REP) have been pr oposed as an alt er n at iv e t o conv en t ion al endodont ic t reat m ent for im m at ure perm anent t eet h, since it allow s cont inuing root developm ent in lengt h and t hickness3,7,21,28.
I n Clin ical Con sider at ion s for a Regen er at iv e
Procedure, Am er ican Associat ion of En dodon t ist s2 ( AAE) ad v ises r oot can al d isin f ect ion , b lood clot f o r m a t i o n a n d c a p p i n g , c e r v i c a l s e a l i n g , a n d crow n rest orat ion. For root canal disinfect ion, AAE2 recom m ends calcium hydroxide ( CH) or t riple ant ibiot ic SDVWH7$3FRQVLVWLQJRIFLSURÀR[DFLQPHWURQLGD]ROH an d m i n o cy cl i n e1 2. Al t h o u g h TAP p r ov i d es g o o d a n t i b a ct e r i a l e f f e ct , ca se r e p o r t s h a v e sh o w n t oot h st ain in g in du ced by m in ocy clin e9 , 1 6 , 2 3. Th u s, alt ernat ive m edicat ions have been proposed, as double DQWLELRWLFSDVWH'$3FRPSRVHGE\FLSURÀR[DFLQDQG m et r onidazole24 RU 7$3 0RGL¿HG SDVWHV 7$30 LQ w hich m inocycline is replaced by ot her ant ibiot ics, as am oxicillin14,24 or cefaclor24,27.
Subsequent ly t o disinfect ion, AAE2 advises a 3- 4 m m layer of MTA, bioceram ic, or glass ionom er cem ent ( GI C) over t he capped clot as cervical sealing. Since even w hit e MTA could induce t oot h discolorat ion11,13, alt ernat ives t o t his m at erial, such as bioceram ics and GI C, have been st rongly indicat ed in t eet h where t here is an est het ic concern2.
Alt h ou g h REP p r ov id es sat isf act or y b iolog ical result s, product s used in t his approach could im pair dent al est het ic, w hich m ay not be revert ed by t oot h bleaching16,20:HGLGQRW¿QGOLWHUDWXUHDVVHVVLQJWRRWK discolorat ion aft er each phase of REP, using different in t r acan al p ast es an d cer v ical sealin g m at er ials, followed by m easuring color aft er bleaching. Therefore, invest igat ion of alt ernat ives t o reduce t oot h est het ic SUHMXGLFHLVMXVWL¿HG7KHDLPVRIWKLVVWXG\ZHUHWR assess t he effect of int racanal m edicat ions and sealing m at erials used in REP on t oot h crown’s color, as well as on t oot h bleaching response. The null hypot heses are: ( 1) m at erials used as int racanal dressing or cervical sealing, in REP, are not able t o induce t oot h crow n discolorat ion; and, ( 2) in case of t oot h discolorat ion prom ot ed by t hose m at erials, dent al bleaching is not able t o recover t oot h color.
Mat erial and m et hods
Toot h select ion and specim en preparat ion
Fif t y bov in e in cisor s w it h sim ilar den t in al w all t hickness were collect ed and disinfect ed by im m ersion in 1.5% sodium hypochlorit e for 3 m in. To sim ulat e an im m at ure t oot h condit ion6 and st andardize specim en lengt h ( 15 m m ) , each t oot h w as sect ioned 5 m m coronally and 10 m m radicularly from t he cem ent um -enam el j unct ion ( CEJ) using a wat er- cooled diam ond disc. Aft er endodont ic access, pulp t issue was rem oved and t he root canal was enlarged w it h a 4103 diam ond bur ( KG Sorensen, Barueri, SP, Brazil) under irrigat ion w it h 3 m L of 1.5% NaOCl, t o st andardize t he int ernal diam et er in 1.6 m m and t hickness of dent inal walls in 1.91±0.37 m m . The last radicular 5 m m w ere sealed w it h wax, and t he root cervical t hird was irrigat ed w it h 3 m L of 1.5% NaOCl follow ed by 3 m L of 17% et hylenediam inet et raacet ic acid ( EDTA, Sigm a-Aldrich, St . Louis, Unit ed St at es) t o rem ove sm ear layer. Root canal was dried w it h absorbent paper point s, a cot t on pellet was placed inside t he root canal and t he crow n w as sealed w it h Cit odu r® ( Dor iDen t , Wien , Wien , Aust ria) . During t hese procedures, t eet h were wrapped up in gauzes em bedded in dist illed wat er t o avoid dehydrat ion; furt herm ore, aft er all preparat ions, t hey w ere st ored subm erged int o 10 m L of dist illed wat er.
Spect rophot om et ry
To st andardize area and light condit ions for color assessm ent , for each t oot h, a cust om silicone m at rix w as f ab r icat ed w it h im p r ession m at er ial ( Per f il®, Vigodent S/ A, Rio de Janeiro, RJ, Brazil) , covering t he ent ire buccal t oot h surface. A perforat ion com pat ible w it h t he size of t he spect rophot om et er t ip (±6 m m diam et er ) w as m ade w it h a cut t ing- edge cy linder at t he crow n area5 ( Figure 1a- c) . Specim ens’ colors were assessed using a digit al spect rophot om et er ( Vit a Easyshade®, VI TA Zahnfabrik H. Raut er Gm bH & Co.KG, %DG6lFNLQJHQ%DGHQ:UWWHPEHUJ*HUPDQ\DQG following t he Com m ission I nternationale de l’Éclairage
( CI E) Lab Syst em , t o obt ain L* ( light ness) , a* and b* ( hue) values.
Phase 1: I nt racanal m edicat ion
Teet h w ere random ly divided int o 1 cont rol ( root canal unt reat ed) and 4 experim ent al groups ( n= 10) , a cco r d i n g t o i n t r a ca n a l m ed i ca t i o n : TAP; TAPM FLSURÀR[DFLQPHWURQLGD]ROHDQGDPR[LFLOOLQ'$3 and CH ( Calen®, SS Whit e, Rio de Janeiro, RJ, Brazil) . Ant ibiot ic past es were prepared by t he sam e pharm acy ( Magist rale Farm ácia de Manipulação, Florianópolis, SC, Brazil) , at 0.1 m g/ m L concent rat ion and equal proport ions of each ant ibiot ic. All past es w ere applied int o t he canals using sy r inge/ needle ( 22 G1) ( BD, Vernon Hills, I L, USA) .
Cor on al sealin g w as p er f or m ed as p r ev iou sly described and t eet h were st ored once again in dist illed wat er. Aft er 1 and 3 days ( d) ; 1, 2, and 3 w eeks ( w ) ; and 1, 2, 3, and 4 m ont hs ( m ) , specim ens had t he excessive m oist ure rem oved w it h gauzes and color shades w ere m easured again.
Thereaft er, int racanal m edicat ions w ere rem oved by saline solut ion irrigat ion and canals were dried wit h absorbent paper point s for t he next phase.
Phase 2: Cervical sealing m at erial
Specim ens fr om each ex per im ent al gr oup w er e random ly subdivided int o 2 subgroups ( n= 5) , according t o t he cervical sealing m at erial: GI C ( Vidrion R®, SS Whit e) or Whit e MTA ( Angelus, Londrina, PR, Brazil) . Follow ing coronal sealing, t he specim ens ret urned t o t he dist illed wat er. Aft er 1d and 3d; 1w, 2w, and 3w ; and 1m and 2m , color shades w ere regist ered again.
Phase 3: Bleaching
Coronal sealing was rem oved t o perform dent al bleaching w it h 37% carbam ide peroxide gel ( BM4 - Brasil Mat eriais e I nst rum ent ais, Palhoça, SC, Brazil) . Teet h w ere insert ed in a polyuret hane sponge soaked w it h dist illed wat er up t o t he CEJ. Bleaching gel was applied inside and out side dent al crow ns for 45 m in,
accor ding t o m anufact ur er ’s r ecom m endat ions. Gel was t hen rem oved by suct ion, specim ens were washed in dist illed wat er, crowns sealed and t eet h wet ly st ored. Color sh ades w er e assessed af t er 2 4 h ou r s. Tw o bleaching sessions were perform ed at 1- week int erval.
Obt ainm ent of color alt erat ion
)RU HDFK VSHFLPHQ WKH SDUDPHWHUV Ʃ/ ƩD ƩEWRPHDVXUHFRORUDOWHUDWLRQƩ(ZHUHFDOFXODWHG VXEWUDFWLQJ WKH LQLWLDO YDOXHV IURP WKH ¿QDO RQHV Ʃ/ /±/ƩD D±DDQGƩE E±EDWHDFKWLPH SHULRGƩ(PHDQVIRUHDFKJURXSDQGH[SHULPHQWDO period w ere calculat ed using t he follow ing equat ion:
,W LV LPSRUWDQW WR KLJKOLJKW WKDW Ʃ( KXPDQ p er cep t i b i l i t y t h r esh o l d w as set at 3 . 7 u n i t s t o det erm ine w hich differences w ere clinically visible1,29.
7KHUHIRUHDQ\WRRWKFRORUDOWHUDWLRQKLJKHUWKDQƩ( 3.7 w ould be perceived by t he hum an eye.
St at ist ical analysis
Dat a were analyzed by Repeat ed Measures Analysis o f Va r i a n ce ( ANOVA) a n d p ost - h oc Ho l m - Si d a k PHWKRGDWDVLJQL¿FDQFHOHYHORI
Result s
Supplem ent al Table 1 provides shades according t o VI TA Classical A1–D4®
Shade Guide fr om t eet h t hroughout experim ent .
Phase 1: I nt racanal m edicat ion
As t h er e w as n o sig n if ican t d if f er en ce in t h e int eract ion bet ween t reat m ent and periods ( P= 0.121) , t h e r esu lt s f r om t h ese v ar iab les w er e p r esen t ed separat ely ( Table 1, Figure 2) . Disregarding t he period, 7$3JURXSSUHVHQWHGWKHKLJKHVWƩ(PHDQDQGWKHUH ZDVDVLJQL¿FDQWGLIIHUHQFHEHWZHHQ7$3DQG7$30 Figure 1- Tooth color assessment devices. (a) Custom silicone matrix covering the entire buccal tooth’s surface, (b,c) with a perforation WR¿WWKHVSHFWURSKRWRPHWHUWLS
JURXSV 7KH ODWWHU VKRZHG Ʃ( PHDQ EHORZ KXPDQ SHUFHSWLRQ WKUHVKROG YDOXH +RZHYHU QR VLJQL¿FDQW difference was found am ong t hese past es and CH, DAP, or Cont rol.
&RQVLGHULQJ RQO\ H[SHULPHQWDO SHULRGV WKH Ʃ(
m eans were equivalent and t he lowest unt il t he second
w eek. On t he ot her hand, t he highest m eans w ere
found at t he last 3m ( Table 1) .
Ph
ase 2: Cervical sealing m at erial
7KHUHZDVVLJQL¿FDQWGLIIHUHQFHLQWKHLQWHUDFWLRQ bet w een t r eat m ent and per iods ( P< 0 . 0 0 1 ) . Thus, result s from t hese variables are present ed t oget her 7DEOH $W EDVHOLQH Ʃ( PHDQV IRU GLIIHUHQW groups w ere different due t o t he effect of int racanal PHGLFDWLRQLQ3KDVH2QO\DWZƩ(PHDQVRI7$3 GI C and TAP/ MTA groups w ere st at ist ically different ( P= 0 . 0 0 5 ) . Con sider in g absolu t e valu es, f r om 3 d t o t he end of t his Phase, TAP/ MTA group present ed WKHKLJKHVWƩ(PHDQVZKLOHDWWKHHQG7$30*,& present ed t he low est one. I n t he groups in w hich t he past es were associat ed wit h GI C, t here was a t endency WRORZHUƩ(PHDQVWKDQLQWKRVHJURXSVLQZKLFK07$ was used. At som e t im e point s, TAPM/ GI C and DAP/ *,& JURXSV SUHVHQWHG Ʃ( PHDQV EHORZ WKH KXPDQ percept ion t hreshold ( Table 2, Figure 3) .
Phase 3: Bleaching
6LJQL¿FDQWGLIIHUHQFHZDVIRXQGLQWKHLQWHUDFWLRQ b et w een t r eat m en t an d b leach in g ( P< 0 . 0 0 1 ) , as SUHVHQWHG LQ 7DEOH $W EDVHOLQH Ʃ( PHDQV RI t his Phase 3 w ere different due t o t he effect of t he PDWHULDOVXVHGLQ3KDVH7KHUHZDVDWHQGHQF\WRƩ( PHDQGHFUHDVHDIWHUEOHDFKLQJ$IWHUWKH¿UVWVHVVLRQ 7$307$Ʃ(PHDQGHFUHDVHGDQGVKRZHGHTXLYDOHQFH wit h ot her groups’ out com es. No difference was found FRPSDULQJ Ʃ( PHDQV ZLWK WKH ¿UVW DQG WKH VHFRQG bleaching sessions w it hin t he sam e group.
I t is w ort h point ing out t hat in CH/ MTA group t he Ʃ( PHDQ DIWHU WKH VHFRQG EOHDFKLQJ LQFUHDVHG DQG becam e higher t han at baseline ( Figure 4, Table 2) .
Treatments ǻ(0HDQ
TAP M 3.5±0.5a
CONTROL 5.25±1.7ab
DAB 5.68±2.2ab
CH 6.16±1.9ab
TAP 8.06±1.5b
Periods ǻ(0HDQ
1d 4.21±2.9a
3d 4.38±2.6a
1w 4.42±2.8a
2w 4.52±3.3ac
1m 5.83±5.1ade
3w 6.15±3.0bd
4m 7.03±5.2bce
2m 7.34±5.9be
3m 7.69±5.4b
ǻ(FRORUFKDQJH&+FDOFLXPK\GUR[LGH'$3GRXEOHDQWLELRWLF SDVWH7$3WULSOHDQWLELRWLFSDVWH7$307$30RGL¿HGGGD\ P PRQWK Z ZHHN 7UHDWPHQW 3 3HULRG 3 Equal letters indicate statistic equivalence.
Table 1-0HDQYDOXHVRIǻ(DQGFRQ¿GHQFHLQWHUYDOVDFFRUGLQJWR treatment and period of evaluation regarding Phase 1 (Intracanal medication)
'HVSLWH WKH QXPHULFDO LQFUHDVH LQ Ʃ( PHDQ FRORU shades accor ding t o VI TA Classical A1–D4® Shade Guide did not change in m ost sam ples ( Supplem ent al Table 1) .
Discussion
Proposed as a t herapy for im m at ure perm anent t eet h , r eg en er at iv e en d od on t ic p r oced u r es h av e been relat ed t o t oot h discolorat ion10,16,23, w hich could event ually lead t o psychological im plicat ions26. So, it is im port ant t o search for t reat m ent s est het ically
predict able.
Al t h o u g h TAP p r ov i d es su i t ab l e an t i b act er i al effect12, t he m inocycline in it s com posit ion has been associat ed wit h dent al st aining9,16,23. Thus, researchers have looked for alt ernat ives t o TAP com posit ion14,24,27. I n t h i s st u d y, TAP, TAPM ( a m ox i ci l l i n r ep l a ci n g m inocycline) , DAP ( TAP w it hout m inocycline) and CH past es w ere used. I n Phase 1, TAP show ed highest color alt erat ion, w hile TAPM show ed t he low est one. These result s suggest t hat replacing m inocycline w it h am ox icillin can lead t o m inor dent al color change, im proving est het ic result s of REP. When m inocycline
TAP TAPM DAP CH Control
GIC MTA GIC MTA GIC MTA GIC MTA
Period Phase 2. Cervical Sealing
Baseline 7.77±0.9abA 9.74±5.8abA 3.46±1.3aA 4.23±2.2acA 2.66±1.4abA 11.94±11.0abA 10.48±5.3acfA 7.73±4.6acdA 6.17±2.7acA 1d 7.29±1.3abAF 10±5.5aACF 3.73±2.6aA 3.85±0.9aA 10.18±1.5aAE 12.12±3.8aDEF 13.98±1.8aDEF 15.71±3.3aBCE 13.61±3.4bBCE 3d 6.65±4.4aAE 11.83±3.2abA 9.01±2.0cAC 8.66±1.6cAD 3.66±1.5bBCDE 7.9±2.5bcAE 7.96±2.4bcAE 8.88±3.2bcAE 5.72±1.3aBCDE 1w 10.41±6.6bA 14.47±4.1abA 12.31±0.3bA 13.27±0.6bA 10.07±1.3acA 10.68±5.5acdA 11.86±1.3adA 11.96±2.6acA 9.4±2.6cA 2w 6.04±2.7aA 12.31±5.0abBC 4.26±0.3aA 5.98±0.8aA 2.56±0.7bA 6.23±1.7bA 7.45±2.4beAC 6.87±2.6bdA 4.34±1.5aA 3w 7.42±0.4abAB 12.45±5.2abA 2.55±1.1aB 4.17±1.0acB 2.53±1.3bB 5.1±2.9bdAB 6.59±3.0bdfAB 8.91±8.5bcAB 4.34±1.6acB 1m 8.21±2.0abAC 15.8±9.4bA 2.70±0.4aBC 4.86±0.7acBC 2.49±0.5bBC 5.18±2.3bdBC 10±3.6acefAC 6.26±2.9bcBC 4.57±1.7aBC 2m 9.13±1.8abAC 13.72±5.5abA 3.63±1.4aBC 6.04±1.8acBC 4.75±2.2bcBC 7.18±2.0bdBC 9.36±3.3acefAC 8.23±3.1bcAC 6.33±2.1acBC
Bleaching Phase 3. Bleaching
Baseline 9.13±1.8aAB 13.72±5.5aA 3.63±1.4aB 6.04±1.8aB 4.75±2.2aB 7.18±2.0aB 9.36±3.3aAB 8.23±3.1acAB 6.33±2.1aB B1 5.05±2.4bA 6.87±5.2bA 4.76±2.5aA 4.19±0.7aA 4.88±2.2aA 7.1±3.8aA 5.54±2.1bA 6.74±1.5aA 5.93±1.3aA B2 4.93±2.1bA 6.48±3.4bA 5.59±2.2aA 4.65±08aA 6.88±1.5aA 6.33±5.5aA 4.19±1.5bA 9.87±4.9bcA 6.67±2.3aA
ǻ(FRORUFKDQJH%EOHDFKLQJ%EOHDFKLQJ&+FDOFLXPK\GUR[LGH'$3GRXEOHDQWLELRWLFSDVWH7$3WULSOHDQWLELRWLFSDVWH 7$30 7$3 PRGL¿HG *,& JODVV LRQRPHU FHPHQW 07$ PLQHUDO WULR[LGH DJJUHJDWH G GD\ P PRQWK Z ZHHN )RU FRPSDULVRQV lowercase letters were used within the columns and uppercase letters within the rows. Equal letters indicate statistic equivalence. Phase 7UHDWPHQW3HULRG33KDVH7UHDWPHQW%OHDFKLQJ3
Table 2-0HDQYDOXHVRIǻ(DQGVWDQGDUGGHYLDWLRQLQ3KDVH7UHDWPHQW3HULRGVDQGLQ3KDVH7UHDWPHQW%OHDFKLQJ
was abolished ( DAP) , color change was low er t han in TAP and higher t han in TAPM groups. Alt hough no VWDWLVWLFDOO\VLJQL¿FDQWGLIIHUHQFHZDVIRXQGEHWZHHQ DAP and TAPM, regarding t oot h color st abilit y, result s suggest t hat ant ibiot ic r eplacing is bet t er t han it s
suppression. How ever, t his result was different from t hat found by Ak cay, et al.1 ( 2014) , in w hich “ TAP
ZLWKDPR[LFLOOLQ´VKRZHGKLJKHUƩ(PHDQVWKDQ'$3 group. Nevert heless, w hile in t his st udy t he past es w ere prepared according t o AAE2 recom m endat ions
PJP/LQWKHVWXG\RIWKRVHDXWKRUVWKH¿QDO concent rat ion of past es is unknow n.
$OOJURXSVVKRZHGYDULDWLRQVLQƩ(PHDQVWKURXJKDOO experim ent al phases, and even Cont rol group show ed som e color change. This result m ay be explained by hydrat ion/ dehydrat ion of dent al st ruct ure, w hich can lead t o color alt erat ions. Dehydrat ion w ould result in replacem ent of wat er by air around t he enam el prism s. At a dehydrat ed enam el- air int erface, t he refract ive and scat t er ing indices ar e differ ent fr om t hose of enam el- wat er int er face. Dehydrat ed enam el w ould VKRZ ORZHU WUDQVOXFHQF\ FDXVLQJ PRUH UHÀHFWLRQ t hus m asking t he underlying dent ine shade, leading t o a light er appearance8. I n t his st udy, t o reduce t he effect of wat er loss during procedures, t he t im e for r ehy drat ion was est ablished in 24 h pr ior t o color m easurem ent s. Even being careful t o rem ove j ust t he excessive m oist ure from t he ext ernal dent al surface and short m anipulat ion t im e ( ± 1 m inut e) t o t ake color shade, som e color alt erat ion was expect ed8,25, since t he m aj or color change in dehydrat ed t eet h occur in WKH¿UVWPLQXWHV8.
Wh en cer v ical sealin g w as p er f or m ed , d en t al st ruct ure was under t he effect of int racanal m edicat ion used in Phase 1. Thus, in Phase 2 t he groups st art ed from different values. I t was observed t hat from 3d unt il t he end of t his Phase, t he highest color alt erat ions ZHUH UHJLVWHUHG IRU 7$307$ $OWKRXJK VLJQL¿FDQW difference was found bet w een TAP/ MTA and TAP/ GI C only at 2w, t his result is especially int erest ing since t he associat ion TAP/ MTA has been lar gely used in clinical pract ice. I t is w ort h point ing out t hat in t he gr oups in w hich past es w er e associat ed w it h GI C, JHQHUDOO\ Ʃ( PHDQV ZHUH ORZHU WKDQ WKRVH IRXQG w hen t hey w er e associat ed w it h MTA, alt hough no VLJQL¿FDQWGLIIHUHQFHZDVIRXQG7KLVZDVH[SHFWHG since st udies have report ed t hat even w hit e MTA can lead t o dent al st aining11,13. The result s of t his st udy
FRQ¿UP WKH $$(2 advice of applying GI C inst ead of MTA as cervical sealing m at erial in areas w here t here is an est het ic concern.
I n t his st udy, a 37% carbam ide peroxide gel was applied inside and out side crow n st ruct ure according t o m anufact urer ’s recom m endat ions. This t echnique is largely used t o bleach non- vit al t eet h. Alt hough REP aim s t o form new vit al t issue w it hin t he root canal, t he coronal pulp space rem ains em pt y. This part icular sit uat ion allow s t reat ing “ vit al t eet h” by a t echnique indicat ed t o non- vit al t eet h, because cervical sealing m at erials prot ect t he vit al t issue from t he bleaching agent .
GROUP SAMPLE BASELINE INTRACANAL MEDICATION CERVICAL SEALING BLEACHING
1w 1m 2m 4m 1w 1m 2m SESSION1 SESSION2
TAP 1 B1 B2 B2 B2 B2 B2 B2 B2 B2 A1 GIC
2 A1 B2 B2 B2 B2 B2 B2 B2 B2 A1
3 A2 B2 B2 B2 B2 B3 B2 B2 B2 A1
4 B2 B2 B2 B2 B2 B3 B2 B2 A1 A1
5 A2 A2 A2 B2 B2 A2 B2 B3 A2 A2
6 A1 B2 B2 B2 B2 B3 B3 B3 A1 A1 MTA
7 B1 B2 B2 B2 B2 B2 B3 B2 B2 B2
8 A2 A2 A2 A2 B2 B3 B3 B3 B2 B2
9 A1 B2 B2 B2 B2 B2 B2 B2 A1 B2
10 A2 A2 A2 A2 B2 B3 B3 B3 B2 B2
TAPM 11 B2 B2 A1 A1 B2 B2 B2 B2 A1 A1 GIC
12 A1 A1 A1 A2 A1 B2 B2 B2 A1 A1
13 B2 B2 B2 B2 B2 B2 B2 B2 B2 A1
14 A2 A2 A2 B2 B2 A2 A2 B2 B2 B2
15 A2 A2 A2 A2 A2 A2 A2 A2 B2 A1
16 A1 A1 A1 A1 A1 B2 B2 B2 B2 B2 MTA
17 A3 A3 A3 A3 A3 B3 B3 B3 B3 B3
18 A2 A3 A2 A3 A2 A3 B3 B3 B3 B2
19 A2 A3 A3 A3 A2 B3 B3 B3 B3 B3
20 A1 A1 A1 B2 B2 B2 B2 B2 A1 A1
DAB 21 A2 A2 B2 A2 A2 B3 B2 B3 A2 B2 GIC
22 A1 A1 A1 B2 B2 B2 B2 B2 A1 B1
23 A1 A1 A1 B2 B2 B2 B2 B2 B1 B1
24 B2 B2 A2 A2 B2 B3 B2 B2 B2 A1
25 B2 B2 B1 B2 B2 B2 B2 B2 A1 A1
26 A3 A2 A3 B3 B3 B3 B3 B3 B3 B3 MTA
27 A2 A2 A2 A2 A2 B2 B2 B3 B2 B2
28 A3.5 A3.5 A3.5 A.35 A3.5 A3.5 A3.5 B4 B3 B3
29 B2 B2 B2 B2 B2 B2 B2 B2 A1 A1
30 A1 A2 B2 A2 B2 B3 B2 B2 B2 B2
CH 31 B1 B2 B2 B2 B2 B2 B2 B2 B2 A1 GIC
32 A1 B2 B2 B2 B3 B2 B2 B2 A1 A1
33 A1 B2 B2 B2 B2 B2 B2 B2 B2 B2
34 B2 B2 B2 B2 B2 B3 B2 B2 B2 A1
35 A2 A2 B2 B2 B2 B2 B2 B2 B2 B2
36 B2 B2 B2 B2 B2 B2 B2 B2 B2 B2 MTA
37 A1 B2 B2 B2 B2 B2 B2 B2 B2 B2
38 A2 B3 B3 B3 B3 B3 B3 B3 B2 B2
39 A2 A3 A3 B3 B2 B3 B3 B3 B3 B3
40 A2 A2 B2 B2 B2 B3 B2 B2 B2 B2
Control 41 B2 B2 B2 B2 A1 B2 B2 B2 B2 B2 UT
42 A1 A1 A1 B2 A2 B2 A1 A1 A1 A1
43 A2 A2 A2 A2 B2 B2 B2 B2 B2 B2
44 A1 A1 A1 C2 A1 B2 A1 B2 A1 A1
45 A2 A2 A1 A2 B2 B2 B2 B2 B2 B2
46 B2 B2 B2 A3 B2 B2 B2 B2 B2 B2
47 A1 A1 A1 B2 A1 B2 A1 A1 A1 A1
48 A2 A2 A2 B2 B2 B2 B2 B2 B2 B2
49 A1 A1 A1 A2 A2 B2 A1 B2 A1 B2
50 B2 A2 A2 B2 A1 B2 B2 B2 B2 B2
&+FDOFLXPK\GUR[LGH'$3GRXEOHDQWLELRWLFSDVWH7$3WULSOHDQWLELRWLFSDVWH7$307$3PRGL¿HG*,&JODVVLRQRPHUFHPHQW07$ mineral trioxide aggregate, UT: untreated. d: day, m: month, w: week.
for CH/ MTA group, no difference was found aft er one or t w o bleaching sessions. This suggest s t hat , under t h ese ex p er im en t al con d it ion s, on ly on e session m ight be enough t o im prove t oot h color. This result is clinically im port ant considering t he num ber of dent al LQWHUYHQWLRQV DQG DSSRLQWPHQWV ZKLFK UHÀHFWV LQ t reat m ent cost s.
'HVSLWHWKHIDFWWKDWWKHUHZDVDUHGXFWLRQLQƩ( PHDQ DIWHU WKH ¿UVW EOHDFKLQJ VHVVLRQ LQ &+07$ group, it t urned t o increase in such a way t hat , aft er t he second session, t he m ean ended higher t han t he regist ered at t he baseline of t his Phase. This m ay be explained by t w o hypot heses. First , t he presence of oxygen in all m at erials used ( CH, MTA, and carbam ide per ox ide) m ay be r elat ed t o t he ov er ox idat ion of bism ut h ox ide15 ZKLFK LV WKH UDGLRSDFL¿HU RI 07$ Bism ut h ox ide has been r elat ed t o t oot h st aining w h en i n co n t a ct w i t h d en t i n m a t r i x co l l a g en1 9. Anot her explanat ion m ay be t he int eract ions am ong t he differ ent m at er ials used, w hich could pr oduce form aldehyde as a byproduct of chem ical react ions. Bism ut h oxide and calcium oxide could st ain dent al st r u ct u r e w h e n i n co n t a ct w i t h f o r m a l d e h y d e4.
+RZHYHUHYHQZLWKWKHLQFUHDVHLQƩ(PHDQWRRWK shades, according t o VI TA Classical A1–D4® Shade
*XLGHGLGQRWFKDQJHEHWZHHQWKH¿UVWDQGWKHVHFRQG bleaching. I t is possible since sm all color difference m ay not det erm ine t he change of a shade for anot her, as t here is an int erval in referent ial values of L* , a* , and, b* bet w een shades22.
A digit al spect rophot om et er was used t o regist er t oot h shades along t he t hree experim ent al phases. Fr om t his device, it is possible t o obt ain values of “ L”, “ a” and “ b” of t he dent al st r uct ur e and, t hen, FDOFXODWHƩ(EHWZHHQWLPHSRLQWV6SHFWURSKRWRPHWHUV becam e largely used in Dent ist ry due t o t heir reliable m et h od of r eadin g t oot h color sh ade. Her e, Vit a Easyshade® was used as it has high reliabilit y and accuracy17. Addit ionally t o t he num erical inform at ion of light ness and hue, t his dev ice pr ov ides shades according t o VI TA Classical A1–D4® Shade Guide, a st andar d and w or ldw ide r efer ence sy st em in t oot h sh ad e d et er m i n at i o n . To f u r t h er av o i d ex t er n al in f lu en ces, silicon e m at r ices w er e cu st om ized t o ensure st andardized area and light condit ions along t he experim ent al phases5. The select ion of t eet h w it h sim ilar dent inal wall t hickness is also im por t ant t o im prove st andardized condit ions18 and, consequent ly, t o im prove reliabilit y of t he com parisons along t he
t im e.
Here, it was invest igat ed t he effect on dent al crown discolorat ion of product s used as int racanal m edicat ion o r cer v i ca l sea l i n g i n r eg en er a t i v e en d o d o n t i cs procedures, as w ell as t he im pact of dent al bleaching aft er regenerat ive approach. Under lim it at ions of an ex
vivo st udy, t he m et hodology was designed t o sim ulat e procedures perform ed in clinics, applying sequent ially product s on t he sam e t oot h t o assess, t hroughout t he experim ent al phases, t he im pact of each of t hem on t oot h color shade.
Conclusion
From t he result s of t his experim ent al ex vivo st udy, we conclude t hat t he evaluat ed int racanal m edicat ions, w h i ch a r e a p p l i e d i n r e g e n e r a t i v e e n d o d o n t i c DSSURDFKHVLQÀXHQFHWRRWKGLVFRORUDWLRQRYHUWLPH bein g TAP t h e m at er ial t h at in du ces h igh er color alt erat ion. On t he ot her hand, cervical sealing m at erial KDVQRLQÀXHQFHRQWRRWKGLVFRORUDWLRQ)XUWKHUPRUH dent al bleaching was able t o recover, at least part ially, WRRWKFRORUVKDGHPDLQO\DW¿UVWDSSOLFDWLRQ
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