Resumo Este estudo in vitro foi testou a hipótese de que o tratamento com flúor pode prevenir a erosão dentária no esmalte fluorótico de diferentes severidades. O objetivo deste estudo foi: investigar o efeito protetor dos fluoretos contra a erosão e abrasão simuladas no esmalte fluorótico. Seguiu um desenho fatorial 3×2, considerando a) severidade da fluorose em 3 níveis: hígido (TF0, Índice Thylstrup-Fejerskov), suave (TF1-2), moderada (TF3-4); b) tratamento com flúor: 0 (controle negativo) e 1150ppmF. Molares humanos com as três severidades de fluorose (n=16, cada) foram selecionados e distribuídos aleatoriamente para os dois tratamentos com flúor (n=8). Blocos de esmalte (4×4mm) foram preparados a partir de cada dente e submetidos a um modelo de ciclo de erosão dentária, por 10 dias. O protocolo de ciclagem diária consistiu em seis desafios erosivos de 5 minutos (1% de ácido cítrico, pH 2,4), intercalados por seis períodos de imersão em saliva artificial e três tratamentos de 2 minutos com 0 ou 1150ppmF. O volume do esmalte perdido foi calculado subtraindo o perfil superficial 3D obtido por microtomografia antes e depois da ciclagem. A ANOVA de dois fatores não mostrou interação significativa entre a severidade da fluorose e o tratamento com flúor (p = 0,691) e nenhum efeito significativo para a severidade da fluorose (TF0 média+/desvio padrão: 13,5(10-2±0,42(10-2, TF1-2: 1,50(10-2±0,52(10-2, TF3-4: 1,24(10-2±0,52(10-2, p=0,416) ou tratamento (0: 1,49(10-2±0,53(10-2; 1150ppmF: 1,21(10-2±0,42(10-2, p=0,093), quando avaliados independentemente. Considerando as limitações deste estudo in vitro, a presença e severidade da fluorose no esmalte não parece afetar sua suscetibilidade à erosão dentária. O tratamento com flúor não foi eficaz na prevenção do desenvolvimento da erosão dentária em esmalte hígido e fluorótico, sob as condições experimentais utilizadas. 32 3×2 níveis TF0, TF0 TF ThylstrupFejerskov, ThylstrupFejerskov Thylstrup Fejerskov , Thylstrup-Fejerskov) TF12, TF12 TF1 (TF1-2) TF34 TF3 4 (TF3-4) b controle negativo 1150ppmF ppmF n=16, n16 n 16 (n=16 n=8. n8 n=8 . 8 (n=8) 4×4mm 44mm mm 4mm (4×4mm 1 dias 1% (1 cítrico 2,4, 24 2,4 2,4) D p 0,691 0691 691 (TF médiadesvio média desvio padrão 13,5102±0,42102, 135102042102 13,5 2±0,42 2, 13 42 13,5(10-2±0,42(10-2 TF1-2 1,50102±0,52102, 150102052102 1,50 2±0,52 50 52 1,50(10-2±0,52(10-2 TF3-4 1,24102±0,52102, 124102052102 1,24 1,24(10-2±0,52(10-2 p=0,416 p0416 416 (0 1,49102±0,53102 149102053102 1,49 2±0,53 49 53 1,49(10-2±0,53(10-2 1,21102±0,42102, 121102042102 1,21 21 1,21(10-2±0,42(10-2 p=0,093, p0093 p=0,093 093 p=0,093) independentemente utilizadas 3× Thylstrup-Fejerskov (TF1-2 (TF3-4 n=16 n1 (n=1 n= (n=8 ( 0,69 069 69 5102 42102 13,5102±0,42102 13510204210 135 13, 2042 2±0,4 13,5(10-2±0,42(10- TF1- 50102 52102 1,50102±0,52102 15010205210 150 1,5 2052 2±0,5 1,50(10-2±0,52(10- TF3- 24102 1,24102±0,52102 12410205210 124 1,2 1,24(10-2±0,52(10- p=0,41 p041 41 49102 53102 1,49102±0,5310 14910205310 149 1,4 2053 1,49(10-2±0,53(10- 21102 1,21102±0,42102 12110204210 121 1,21(10-2±0,42(10- p009 p=0,09 09 (TF1- (TF3- n=1 (n= 0,6 06 6 510 4210 13,5102±0,4210 1351020421 204 2±0, 13,5(10-2±0,42(10 5010 5210 1,50102±0,5210 1501020521 15 1, 205 1,50(10-2±0,52(10 2410 1,24102±0,5210 1241020521 12 1,24(10-2±0,52(10 p=0,4 p04 4910 5310 1,49102±0,531 1491020531 14 1,49(10-2±0,53(10 2110 1,21102±0,4210 1211020421 1,21(10-2±0,42(10 p00 p=0,0 (TF1 (TF3 (n 0, 51 421 13,5102±0,421 135102042 20 2±0 13,5(10-2±0,42(1 501 521 1,50102±0,521 150102052 1,50(10-2±0,52(1 241 1,24102±0,521 124102052 1,24(10-2±0,52(1 p=0, p0 491 531 1,49102±0,53 149102053 1,49(10-2±0,53(1 211 1,21102±0,421 121102042 1,21(10-2±0,42(1 13,5102±0,42 13510204 2± 13,5(10-2±0,42( 1,50102±0,52 15010205 1,50(10-2±0,52( 1,24102±0,52 12410205 1,24(10-2±0,52( p=0 1,49102±0,5 14910205 1,49(10-2±0,53( 1,21102±0,42 12110204 1,21(10-2±0,42( 13,5102±0,4 1351020 13,5(10-2±0,42 1,50102±0,5 1501020 1,50(10-2±0,52 1,24102±0,5 1241020 1,24(10-2±0,52 p= 1,49102±0, 1491020 1,49(10-2±0,53 1,21102±0,4 1211020 1,21(10-2±0,42 13,5102±0, 135102 13,5(10-2±0,4 1,50102±0, 150102 1,50(10-2±0,5 1,24102±0, 124102 1,24(10-2±0,5 1,49102±0 149102 1,49(10-2±0,5 1,21102±0, 121102 1,21(10-2±0,4 13,5102±0 13510 13,5(10-2±0, 1,50102±0 15010 1,50(10-2±0, 1,24102±0 12410 1,24(10-2±0, 1,49102± 14910 1,49(10-2±0, 1,21102±0 12110 1,21(10-2±0, 13,5102± 1351 13,5(10-2±0 1,50102± 1501 1,50(10-2±0 1,24102± 1241 1,24(10-2±0 1,49102 1491 1,49(10-2±0 1,21102± 1211 1,21(10-2±0 13,5102 13,5(10-2± 1,50102 1,50(10-2± 1,24102 1,24(10-2± 1,4910 1,49(10-2± 1,21102 1,21(10-2± 13,510 13,5(10-2 1,5010 1,50(10-2 1,2410 1,24(10-2 1,491 1,49(10-2 1,2110 1,21(10-2 13,51 13,5(10- 1,501 1,50(10- 1,241 1,24(10- 1,49(10- 1,211 1,21(10- 13,5(10 1,50(10 1,24(10 1,49(10 1,21(10 13,5(1 1,50(1 1,24(1 1,49(1 1,21(1 13,5( 1,50( 1,24( 1,49( 1,21(
Abstract The purpose of this in vitro study was to test the hypothesis that fluoride treatment can prevent dental erosion on fluorotic enamel of different severities. It followed a 3×2 factorial design, considering a) fluorosis severity: sound (TF0, Thylstrup-Fejerskov Index), mild (TF1-2), moderate (TF3-4); and b) fluoride treatment: 0 (negative control) and 1150ppmF. Human molars with the three fluorosis severities (n=16, each) were selected and randomly assigned to the two fluoride treatments (n=8). Enamel blocks (4×4mm) were prepared from each tooth and subjected to a dental erosion cycling model, for 10 days. The daily cycling protocol consisted of erosive challenges (1% citric acid, pH 2.4), interspersed by periods of immersion in artificial saliva, and three 2-minute treatments with either 0 or 1150ppm F. The enamel volume loss (mm3) was calculated by subtracting values obtained by microtomography before and after cycling. Two-Way ANOVA showed no significant interaction between fluorosis severity and fluoride treatment (p=0.691), and no significant effect for either fluorosis severity (TF0 mean±standard-deviation: 13.5(10-2±0.42(10-2, TF1-2: 1.50(10-2±0.52(10-2, TF3-4: 1.24(10-2±0.52(10-2, p=0.416) or treatment (0ppmF: 1.49(10-2±0.53(10-2; 1150ppmF: 1.21(10-2±0.42(10-2; p=0.093), when evaluated independently. Considering the limitations of this in vitro study, the presence and severity of fluorosis in enamel do not appear to affect its susceptibility to dental erosion. Fluoride treatment was not effective in preventing the development of dental erosion in both sound and fluorotic enamel substrates under our experimental conditions. 32 3 2 3× design TF0, TF0 TF ThylstrupFejerskov Thylstrup Fejerskov Index, Index , Index) TF12, TF12 TF1 (TF1-2) TF34 TF3 4 (TF3-4) b negative control 1150ppmF ppmF n=16, n16 n 16 (n=16 n=8. n8 n=8 . 8 (n=8) 4×4mm 44mm mm 4mm (4×4mm model 1 days 1% (1 acid 2.4, 24 2.4 2.4) saliva 2minute minute ppm F mm3 (mm3 TwoWay Two Way p=0.691, p0691 p p=0.691 691 (p=0.691) (TF mean±standarddeviation meanstandarddeviation mean±standard deviation mean standard mean±standard-deviation 13.5102±0.42102, 135102042102 13.5 2±0.42 2, 13 5 42 13.5(10-2±0.42(10-2 TF1-2 1.50102±0.52102, 150102052102 1.50 2±0.52 50 52 1.50(10-2±0.52(10-2 TF3-4 1.24102±0.52102, 124102052102 1.24 1.24(10-2±0.52(10-2 p=0.416 p0416 416 0ppmF (0ppmF 1.49102±0.53102 149102053102 1.49 2±0.53 49 53 1.49(10-2±0.53(10-2 1.21102±0.42102 121102042102 1.21 21 1.21(10-2±0.42(10-2 p=0.093, p0093 p=0.093 093 p=0.093) independently conditions (TF1-2 (TF3-4 n=16 n1 (n=1 n= (n=8 ( 2. (mm p069 p=0.69 69 (p=0.691 standarddeviation meanstandard 5102 42102 13.5102±0.42102 13510204210 135 13. 2042 2±0.4 13.5(10-2±0.42(10- TF1- 50102 52102 1.50102±0.52102 15010205210 150 1.5 2052 2±0.5 1.50(10-2±0.52(10- TF3- 24102 1.24102±0.52102 12410205210 124 1.2 1.24(10-2±0.52(10- p=0.41 p041 41 49102 53102 1.49102±0.5310 14910205310 149 1.4 2053 1.49(10-2±0.53(10- 21102 1.21102±0.4210 12110204210 121 1.21(10-2±0.42(10- p009 p=0.09 09 (TF1- (TF3- n=1 (n= p06 p=0.6 6 (p=0.69 510 4210 13.5102±0.4210 1351020421 204 2±0. 13.5(10-2±0.42(10 5010 5210 1.50102±0.5210 1501020521 15 1. 205 1.50(10-2±0.52(10 2410 1.24102±0.5210 1241020521 12 1.24(10-2±0.52(10 p=0.4 p04 4910 5310 1.49102±0.531 1491020531 14 1.49(10-2±0.53(10 2110 1.21102±0.421 1211020421 1.21(10-2±0.42(10 p00 p=0.0 (TF1 (TF3 (n p0 p=0. (p=0.6 51 421 13.5102±0.421 135102042 20 2±0 13.5(10-2±0.42(1 501 521 1.50102±0.521 150102052 1.50(10-2±0.52(1 241 1.24102±0.521 124102052 1.24(10-2±0.52(1 491 531 1.49102±0.53 149102053 1.49(10-2±0.53(1 211 1.21102±0.42 121102042 1.21(10-2±0.42(1 p=0 (p=0. 13.5102±0.42 13510204 2± 13.5(10-2±0.42( 1.50102±0.52 15010205 1.50(10-2±0.52( 1.24102±0.52 12410205 1.24(10-2±0.52( 1.49102±0.5 14910205 1.49(10-2±0.53( 1.21102±0.4 12110204 1.21(10-2±0.42( p= (p=0 13.5102±0.4 1351020 13.5(10-2±0.42 1.50102±0.5 1501020 1.50(10-2±0.52 1.24102±0.5 1241020 1.24(10-2±0.52 1.49102±0. 1491020 1.49(10-2±0.53 1.21102±0. 1211020 1.21(10-2±0.42 (p= 13.5102±0. 135102 13.5(10-2±0.4 1.50102±0. 150102 1.50(10-2±0.5 1.24102±0. 124102 1.24(10-2±0.5 1.49102±0 149102 1.49(10-2±0.5 1.21102±0 121102 1.21(10-2±0.4 (p 13.5102±0 13510 13.5(10-2±0. 1.50102±0 15010 1.50(10-2±0. 1.24102±0 12410 1.24(10-2±0. 1.49102± 14910 1.49(10-2±0. 1.21102± 12110 1.21(10-2±0. 13.5102± 1351 13.5(10-2±0 1.50102± 1501 1.50(10-2±0 1.24102± 1241 1.24(10-2±0 1.49102 1491 1.49(10-2±0 1.21102 1211 1.21(10-2±0 13.5102 13.5(10-2± 1.50102 1.50(10-2± 1.24102 1.24(10-2± 1.4910 1.49(10-2± 1.2110 1.21(10-2± 13.510 13.5(10-2 1.5010 1.50(10-2 1.2410 1.24(10-2 1.491 1.49(10-2 1.211 1.21(10-2 13.51 13.5(10- 1.501 1.50(10- 1.241 1.24(10- 1.49(10- 1.21(10- 13.5(10 1.50(10 1.24(10 1.49(10 1.21(10 13.5(1 1.50(1 1.24(1 1.49(1 1.21(1 13.5( 1.50( 1.24( 1.49( 1.21(