Carbamide peroxide gel stability under different temperature conditions: is manipulated formulation an option?

Nowadays the use of gel containing carbamide peroxide (CP) prepared in Pharmacy is a normal practice in the population. However, the quality of this product is questionable concerning its stability. The aim of this study is was to synthesize and to analyze this drug alone or associated to Carbopol gel through analytical methodology compatible with the routine of the Pharmacies. The reaction between urea and hydrogen peroxide was carried out at different resting times: 24 hours (CP 24 powder) and 48 hours (CP48 powder) after the mixture. Both products were associated with Carbopol 940® gel 1.5% (G) generating G24 and G48 samples. The stability of powders (CP24 e CP48) and the formulations (G24 and G48) were evaluated as a function of time (15, 40 and 45 days) and thermal variation (refrigeration: 8 °C±1; thermal shock 32 °C±1 /8 °C±1; stove: 32 °C±1), using a standard titration method. As a result, only under refrigeration the CP24 and CP48 contents remained stable during the period of 45 days. An interesting finding was that G24 and G48 presented greater stability for at least 45-days under refrigeration and thermal shock conditions, and up to 30 days under stove conditions. The results for the G24 and G48 were slightly higher than those obtained for the control. Therefore, we were able to conclude that association with Carbopol 940® Gel 1.5 % provided greater CP stability and that manipulated formulations containing CP may be viable for use in a period of 45 days under refrigeration conditions. The titration proved to be an effective technique for the analysis of CP with or without Carbopol 940® gel 1.5%.Atualmente, a utilização de gel contendo peróxido de carbamida manipulado em Farmácia é uma prática comum na população. No entanto, a qualidade deste produto é questionada, sobretudo no que se refere à estabilidade deste fármaco. O objetivo deste trabalho consiste na avaliação da viabilidade de sintetizar e analisar quantitativamente este fármaco associado ou não a um gel de Carbopol através de metodologia analítica compatível com a rotina das Farmácias. A reação entre a uréia e o peróxido de hidrogênio foi realizada em tempos diferentes de repouso após a mistura, 24 h para sintetizar o pó PC 24 e 48 h para o pó CP 48. Estes pós foram associados a um gel (G) de Carbopol 940® 1,5 %, originando as amostras G24 e G48. A estabilidade dos pós (PC 24 e PC 48) e das formulações (G 24 e G 48) foi avaliada em função do tempo (15, 40 e 45 dias) e da variação térmica (refrigeração: 8 °C±1; choque térmico: 32 °C±1/8 °C±1 e estufa: 32 °C±1), através da técnica de titulometria. Os resultados indicam que unicamente sob refrigeração o CP24 e o CP 48 mantiveram-se estáveis no período de 45 dias. O G24 e o G48 apresentaram estáveis por pelo menos 45 dias nas condições de refrigeração e choque térmico e por 30 dias na condição estufa. Os resultados obtidos para o G24 e G48 foram ligeiramente superiores aos obtidos para o controle. Além disso, é possível concluir que a associação do PC com o gel de Carbopol 940® 1,5 % promoveu um aumento na estabilidade do PC e que as preparações manipuladas contendo PC são viáveis para uso durante um período de 45 sob refrigeração. A titulometria mostrou-se uma técnica eficaz para a análise do PC associado ou não ao gel de Carbopol 940® 1,5%

The Effect Of 10% Carbamide Peroxide Bleaching Material On Microhardness Of Sound And Demineralized Enamel And Dentin In Situ.

This in situ study evaluated the microhardness of sound and demineralized enamel and dentin submitted to treatment with 10% carbamide peroxide for three weeks. A 10% carbamide peroxide bleaching agent--Opalescence/Ultradent (OPA)--was evaluated against a placebo agent (PLA). Two hundred and forty dental fragments--60 sound enamel fragments (SE), 60 demineralized enamel fragments (DE), 60 sound dentin fragments (SD) and 60 demineralized dentin fragments (DD)--were randomly fixed on the vestibular surface of the first superior molars and second superior premolars of 30 volunteers. The volunteers were divided into two groups that received bleaching or the placebo agent at different sequences and periods at a double blind 2 x 2 crossover study with a wash-out period of two weeks. Microhardness tests were performed on the enamel and dentin surface. The SE and DE submitted to treatment with OPA showed lower microhardness values than the SE and DE submitted to treatment with PLA. There were no statistical differences in microhardness values for SD and DD submitted to the treatment with OPA and PLA. The results suggest that treatment with 10% carbamide peroxide bleaching material for three weeks alters the enamel microhardness, although it does not seem to alter the dentin microhardness.26653153

Morphology And Microtensile Bond Strength Of Adhesive Systems To In Situ-formed Caries-affected Dentin After The Use Of A Papain-based Chemomechanical Gel Method

Purpose: To evaluate the microtensile bond strength of adhesive systems to caries-affected dentin formed in situ after the use of a papain-based chemomechanical removal method. Methods: 84 human dentin specimens (5 × 5 × 3 mm) were sterilized and randomly distributed on palatal devices of 14 volunteers. Each palatal device, containing six dentin slabs, was used for 14 days according to a caries induction design involving plaque accumulation and sucrose use. After this, fragments were removed from devices and randomly assigned to two groups according to the caries removal method: (1) Chemomechanical (papain-based gel followed by curette), or (2) Mechanical (curette - control group). Specimens were subdivided into three subgroups according to the adhesive system tested: (SB) a two-step etchand-rinse (Adper Single Bond 2); (SE) a two-step self-etching adhesive (Clearfil SE Bond) and (TriS) a one-step selfetching adhesive (Clearfil Tri-S Bond) and subsequently restored with microhybrid composite resin. After 24 hours, resin-tooth blocks were sectioned into 0.9 mm thick slabs, with one slab of each block being prepared for adhesive interface analysis by scanning electron microscopy, and the remaining blocks were sectioned into 0.8-mm2 sticks that were subjected to tensile stress (0.5 mm/minute). Data were subjected to two-way ANOVA and Tukey's test at a 5% level of significance. Results: The application of the chemomechanical and mechanical methods to demineralized dentin did not affect the bond strength values. SB and SE adhesives promoted statistically similar and significantly higher bond strength values than the TriS. SEM analysis showed no interference of papain-based gel in the formation of hybrid layer; SB showed the thickest hybrid layer with presence of numerous tags; SE showed an intermediate hybrid layer thickness and quantity of tags and the TriS showed no evidence of tag formation.2411319Tyas, M.J., Anusavice, K.J., Francken, J.E., Mount, G.J., Minimal intervention dentistry. A review. FDI Commission Project 1 -97 (2000) Int Dent J, 50, pp. 11-12Fusayama, T., Two layers of carious dentine: Diagnosis and treatment (1979) Oper Dent, 4, pp. 63-70Bjorndal, L., Larsen, T., Thylstrup, A., A clinical and microbiological study of deep carious lesions during stepwise excavation using long treatment intervals (1997) Caries Research, 31 (6), pp. 411-417Mertz-Fairhurst, E.J., Curtis Jr., J.W., Ergle, J.W., Rueggeberg, F.A., Adair, S.M., Ultraconservative and cariostatic sealed restorations: Results at year 10 (1998) Journal of the American Dental Association, 129 (1), pp. 55-66Nadanovsky, P., Cohen, C.F., Souza, D.M.F., Removal of caries using only hand instruments: A comparison of mechanical and chemo-mechanical methods (2001) Caries Research, 35 (5), pp. 384-389. , DOI 10.1159/000047478Eden, E., Topaloglu-Ak, A., Frencken, J.E., Van'T Hof, M., Survival of self-etch adhesive Class II composite restorations using ATR and conventional cavity preparation in primary molars (2006) Am J Dent, 19, pp. 359-363Uribe, S., Partial caries removal in symptomless teeth reduces the risk of pulp exposure (2006) Evid Based Dent, 7, p. 94Banerjee, A., Watson, T.F., Kidd, E.A., Dentine caries excavation: A review of current clinical techniques (2000) Br Dent J, 188, pp. 476-482Haak, R., Wicht, M.J., Noack, M.J., Does chemomechanical caries removal affect dentine adhesion? (2000) Eur J Oral Sci, 108, pp. 449-455Maragakis, G.M., Hahn, P., Hellwig, E., Chemomechanical caries removal: A comprehensive review of the literature (2001) International Dental Journal, 51 (4), pp. 291-299Azrak, B., Callaway, A., Grundheber, A., Stender, E., Willershausen, B., Comparison of the efficacy of chemomechanical caries removal (Carisolv) with that of conventional excavation in reducing the cariogenic flora (2004) International Journal of Paediatric Dentistry, 14 (3), pp. 182-191. , DOI 10.1111/j.1365-263X.2004.00535.xDammaschke, T., Stratmann, U., Mokrys, K., Kaup, M., Ott, K.H.R., Reaction of sound and demineralised dentine to Carisolv in vivo and in vitro (2002) Journal of Dentistry, 30 (1), pp. 59-65. , DOI 10.1016/S0300-5712(01)00060-4, PII S0300571201000604Topaloglu-Ak, A., Eden, E., Frencken, J.E., Oncag, O., Two years survival rate of class II composite resin restorations prepared by ART with and without a chemomechanical caries removal gel in primary molars (2009) Clin Oral Investig, 13, pp. 325-332Bussadori, S.K., Castro, L.C., Galvao, A.C., Papain gel: A new chemo-mechanical caries removal agent (2005) Journal of Clinical Pediatric Dentistry, 30 (2), pp. 115-119Ahmed, A.A.R., Garcia-Godoy, F., Kunzelmann, K.-H., Self-limiting caries therapy with proteolytic agents (2008) Am J Dent, 21, pp. 303-312Flindt, M., Health and safety aspects of working with enzymes (1979) Process Biochem, 13, pp. 3-7Bussadori, S.K., Guedes, C.C., Hermida Bruno, M.L., Ram, D., Chemo-mechanical removal of caries in an adolescent patient using a papain gel: Case report (2008) J Clin Pediatr Dent, 32, pp. 177-180Gianini, R.J., Amaral, F.L.B., Flório, F.M., Basting, R.T., Microtensile bond strength of etch-and-rinse and self-etch adhesive systems to demineralized dentin after the use of a papain-based chemomechanical method (2010) Am J Dent, 23, pp. 23-28Lopes, M.C., Mascarini, R.C., Silva, B., Flório, F.M., Basting, R.T., Effect of papain-based gel for chemomechanical caries removal on dentin shear bond strength (2007) J Dent Child (Chic), 74, pp. 93-97White, D.J., The application of in vitro models to research on demin-eralization and remineralization of the teeth (1995) Adv Dent Res, 9, pp. 175-193Hara, A.T., Queiroz, C.S., Giannini, M., Cury, J.A., Serra, M.C., Influence of the mineral content and morphological pattern of artificial root caries lesion on composite resin bond strength (2004) European Journal of Oral Sciences, 112 (1), pp. 67-72. , DOI 10.1111/j.0909-8836.2004.00093.xErhardt, M.C.G., Rodrigues, J.A., Valentino, T.A., Ritter, A.V., Pimenta, L.A.F., In vitro TBS of one-bottle adhesive systems: Sound versus artificially-created caries-affected dentin (2008) Journal of Biomedical Materials Research - Part B Applied Biomaterials, 86 (1), pp. 181-187. , DOI 10.1002/jbm.b.31004Zero, D.T., Insitu caries models (1995) Adv Dent Res, 9, pp. 214-230Aires, C.P., Tabchoury, C.P.M., Del Bel Cury, A.A., Cury, J.A., Effect of a lactose-containing sweetener on root dentine demineralization in situ (2002) Caries Res, 36, pp. 167-169Hara, A.T., Queiroz, C.S., Paes, L.A.F., Serra, M.C., Cury, J.A., Caries progression and inhibition in human and bovine root dentine in situ (2003) Caries Research, 37 (5), pp. 339-344. , DOI 10.1159/000072165Ten Cate, J.M., Van Duinen, R.N.B., Hypermineralization of dentinal lesions adjacent to glass-ionomer cement restorations (1995) J Dent Res, 74, pp. 1266-1271Ten Cate, J.M., In situ models, physico-chemical aspects (1994) Adv Dent Res, 8, pp. 125-133Osorio, R., Pisani-Proenca, J., Erhardt, M.C., Osorio, E., Aguilera, F.S., Tay, F.R., Toledano, M., Resistance often contemporary adhesives to resin-dentine bond degradation (2008) J Dent, 36, pp. 163-169Van Landuyt, K.L., Snauwaert, J., De Munck, J., Peumans, M., Yoshida, Y., Poitevin, A., Coutinho, E., Van Meerbeek, B., Systematic review of the chemical composition of contemporary dental adhesives (2007) Biomaterials, 28 (26), pp. 3757-3785. , DOI 10.1016/j.biomaterials.2007.04.044, PII S0142961207003596Pashley, E.L., Tao, L., Pashley, D.H., Sterilization of human teeth: Its effect on permeability and bond strength (1993) Am J Dent, 6, pp. 189-191Radovic, I., Vulicevic, Z.R., Garcia-Godoy, F., Morphological evaluation of 2- and 1-step self-etching system interfaces with dentin (2006) Operative Dentistry, 31 (6), pp. 710-718. , DOI 10.2341/05-145Kidd, E.A.M., Fejerskov, O., What constitutes dental caries? Histopathology of carious enamel and dentin related to the action of cariogenic biofilms (2004) Journal of Dental Research, 83 (SPEC. ISS. C), pp. C35-C38. , DOI 10.1177/154405910408301S07Massler, M., Pulpal reactions to dental caries (1967) Int Dent J, 17, pp. 441-460Erhardt, M.C.G., Amaral, C.M., De Castro, A.K.B.B., Ambrosano, G.M.B., Pimenta, L.A.F., In vitro influence of Carisolv on shear bond strength of dentin bonding agents (2004) Quintessence International, 35 (10), pp. 801-807Hosoya, Y., Kawashita, Y., Marshall Jr., G.W., Goto, G., Influence of Carisolv for resin adhesion to sound human primary dentin and young permanent dentin (2001) Journal of Dentistry, 29 (3), pp. 163-171. , DOI 10.1016/S0300-5712(01)00006-9, PII S0300571201000069Banerjee, A., Kidd, E.A., Watson, T.F., Scanning electron microscopic observations of human dentine after mechanical caries excavation (2000) Caries Res, 28, pp. 179-186Corrêa, F.N., Rodrigues Filho, L.E., Rodrigues, C.R., Evaluation of residual dentin after conventional and chemomechanical caries removal using SEM (2008) J Clin Pediatr Dent, 32, pp. 115-120Cederlund, A., Lindskog, S., Blomlof, J., Effect of a chemo-mechanical caries removal system (Carisolv(TM)) on dentin topography of non-carious dentin (1999) Acta Odontologica Scandinavica, 57 (4), pp. 185-189. , DOI 10.1080/000163599428751Yazici, A.R., Ozgunaltay, G., Dayangac, B., A scanning electron microscopic study of different caries removal techniques on human dentin (2002) Operative Dentistry, 27 (4), pp. 360-366Piva, E., Ogliari, F.A., Moraes, R.R., Corá, F., Henn, S., Correr-Sobrinho, L., Papain-based gel for biochemical caries removal: Influence on microtensile bond strength to dentin (2008) Braz Oral Res, 22, pp. 364-370Cehreli, Z.C., Yazici, A.R., Akca, T., Ozgunaltay, G., A morphological and micro-tensile bond strength evaluation of a single-bottle adhesive to caries-affected human dentine after four different caries removal techniques (2003) Journal of Dentistry, 31 (6), pp. 429-435. , DOI 10.1016/S0300-5712(03)00011-3Erhardt, M.C.G., Toledano, M., Osorio, R., Pimenta, L.A., Histomorphologic characterization and bond strength evaluation of caries-affected dentin/resin interfaces: Effects of long-term water exposure (2008) Dental Materials, 24 (6), pp. 786-798. , DOI 10.1016/j.dental.2007.09.007, PII S0109564107002308Van Meerbeek, B., De Munck, J., Yoshida, Y., Inoue, S., Vargas, M., Vijay, P., Van Landuyt, K., Vannerie, G., Buonocore memorial lecture. Adhesion to enamel and dentin: Current status and future challenges (2003) Oper Dent, 28, pp. 215-1213Yoshida, Y., Nagakane, K., Fukuda, R., Nakayama, Y., Okazaki, M., Shintani, H., Inoue, S., Van Meerbeek, B., Comparative study on adhesive performance of functional monomers (2004) Journal of Dental Research, 83 (6), pp. 454-458Sakoolnamarka, R., Burrow, M.F., Tyas, M.J., Interfacial micromorphology of three adhesive systems created in caries-affected dentin (2003) American Journal of Dentistry, 16 (3), pp. 202-206Kubo, S., Li, H., Burrow, M.F., Tyas, M.J., Nanoleakage of dentin adhesive systems bonded to carisolv-treated dentin (2002) Operative Dentistry, 27 (4), pp. 387-395Kaneshiro, A.V., Imazato, S., Ebisu, S., Comparison of bonding ability of single-step self-etching adhesives with different etching aggressiveness to root dentin (2007) Dent Mater J, 26, pp. 773-784Arisu, H.D., Eligüzeloǧlu, E., Uçtaşli, M.B., Omürlü, H., Effect of multiple consecutive applications of one-step self-etch adhesive on microtensile bond strength (2009) J Contemp Dent Pract, pp. 1067-107

Analysis Of Total Microbiota In Dentin After Mechanical Or Papain-based Chemomechanical Caries Removal

Chemomechanical caries removal, when compared with removal using conventional rotary instruments, seems to preserve healthy tooth structure with less trauma to the patient. This study performed in vivo analysis of the total number of microorganisms in dentin after the use of conventional or chemomechanical (papain gel) caries removal methods. Analyses were performed before caries removal (baseline), immediately after caries removal, and 45 days after caries removal and temporary cavity sealing. Sixty patients were selected for this study, each with two mandibular molars (one on each side) with occlusal caries of moderate depth, for a total of 120 teeth. For each patient, the carious lesion of one tooth was removed by conventional methods using low speed drills (Group 1). For the other tooth, a chemomechanical method was used (Group 2). Dentin samples were collected at the 3 intervals and subjected to microbiological culture in blood agar. For the total number of microorganisms in both groups, ANOVA and Tukey tests (which considered the baseline values as a covariable) showed a higher microbial count immediately after the preparation of the cavity compared to the count at 45 days (P < 0.05). For both groups, the total count of microorganisms in dentin decreased 45 days after placing the temporary cavity sealing.6145963Tyas, M.J., Anusavice, K.J., Francken, J.E., Mount, G.J., Minimal intervention dentistry-A review. FDI Commission Project 1-97 (2000) Int Dent J, 50 (1), pp. 1-12Kakaboura, A., Masouras, C., Staikou, O., Vougiouklakis, G., A comparative clinical study on the Carisolv caries removal method (2003) Quintessence Int, 34 (4), pp. 269-271Bussadori, S.K., Castro, L.C., Galvao, A.C., Papain gel: A new chemo-mechanical caries removal agent (2005) J Clin Pediatr Dent, 30 (2), pp. 115-119Motta, L.J., Martins, M.D., Porta, K.P., Bussadori, S.K., Aesthetic restoration of deciduous anterior teeth after removal of carious tissue with Papacarie (2009) Indian J Dental Res, 20 (1), pp. 117-120Wambier, D.S., Dos Santos, F.A., Guedes-Pinto, A.C., Jaeger, R.G., Simionato, M.R., Ultrastructural and microbiological analysis of the dentin layers affected by caries lesions in primary molars treated by minimal intervention (2007) Pediatr Dent, 29 (3), pp. 228-234Fusayama, T., Two layers of carious dentin: Diagnosis and treatment (1979) Oper Dent, 4 (2), pp. 63-70Nadanovsky, P., Carneiro, F.C., Souza De Mello, F., Removal of caries using only hand instruments: A comparison of mechanical and chemo-mechanical methods (2001) Caries Res, 35 (5), pp. 384-389Goldman, M., Kronman, J.H., A preliminary report on a chemomechanical means of removing caries (1976) J Am Dent Assoc, 93 (6), pp. 1149-1153McNierney, H.D., Petruzillo, M.A., A gentle approach to operative dentistry: The Caridex caries removal system (1986) Gen Dent, 34 (4), pp. 282-284. , 1986Gu, Z.Q., Chen, Q.M., Wei, S., The clinical application of a chemomechanical caries removal system (Caridex): A comparative study (1987) Compendium, 8 (8), pp. 638-640Tonami, K., Araki, K., Mataki, S., Kurosaki, N., Effects of chloramines and sodium hypochlorite on carious dentin (2003) J Med Dent Sci, 50 (2), pp. 139-146Hosoya, Y., Kawashita, Y., Marshall Jr., G.W., Goto, G., Influence of Carisolv for resin adhesion to sound human primary dentin and young permanent dentin (2001) J Dent, 29 (3), pp. 163-171Dammaschke, T., Stratmann, U., Mokrys, K., Kaup, M., Reiner Ott, K.H., Reaction of sound and demineralised dentine to Carisolv in vivo and in vitro (2002) J Dent, 30 (1), pp. 59-65Flindt, M., Health and safety aspects of working with enzymes (1979) Proc Biochem, 13 (8), pp. 3-7Bertassoni, L.E., Marshall, G.W., Papain-gel degrades intact nonmineralized type I collagen fibrils (2009) Scanning, 31 (6), pp. 253-258Ahmed, A.A., Garcia-Godoy, F., Kunzelmann, K.H., Self-limiting caries therapy with proteolytic agents (2008) Am J Dent, 21 (5), pp. 303-312Martins, M.D., Fernandes, K.P., Motta, L.J., Santos, E.M., Pavesi, V.C., Bussadori, S.K., Biocompatibility analysis of chemomechanical caries removal material Papacarie on cultured fibroblasts and subcutaneous tissue (2009) J Dent Child, 76 (2), pp. 123-129Ikeda, T., Sandham, H.J., Bradley Jr., E.L., Changes in mutans streptococci and lactobacilli in plaque in relation to the initiation of dental caries in Negro children (1973) Arch Oral Biol, 18 (4), pp. 555-565Bentley, C., Crawford, J.J., Broderius, C.A., Analytical and physiological variability of salivary microbial counts (1988) J Dent Res, 67 (11), pp. 1409-1413Mount, G.J., Ngo, H., Minimal intervention: A new concept for operative dentistry (2000) Quintessence Int, 31 (9), pp. 527-533Bittencourt, S.T., Pereira, J.R., Rosa, A.W., Oliveira, K.S., Ghizoni, J.S., Oliveira, M.T., Mineral content removal after Papacarie application in primary teeth: A quantitative analysis (2010) J Clin Pediatr Dent, 34 (3), pp. 229-231Yip, H.K., Beeley, J.A., Stevenson, A.G., Mineral content of the dentine remaining after chemomechanical caries removal (1995) Caries Res, 29 (2), pp. 111-117Correa, F.N., Rocha, R.O., Soares, F.Z., Rodrigues-Filho, L.E., Rodrigues, C.R., Fluorescence of primary dentine after chemomechanical and conventional rotary excavation (2008) Eur Arch Paeditr Dent, 9 (3), pp. 126-129Ferreira, C.M., Da Silva Rosa, O.P., Torres, S.A., Ferreira, F.B., Bernardinelli, N., Activity of endodontic antibacterial agents against selected anaerobic bacteria (2002) Braz Dent J, 13 (2), pp. 118-122Lai, C.C., Huang, F.M., Yang, H.W., Antimicrobial activity of four root canal sealers against endodontic pathogens (2001) Clin Oral Investig, 5 (4), pp. 236-239Saha, S., Samadi, F., Jaiswal, J.N., Ghoshal, U., Antimicrobial activity of different endodontic sealers: An in vitro evaluation (2010) J Indian Soc Pedod Prev Dent, 28 (4), pp. 251-257Lula, E.C., Monteiro-Neto, V., Alves, C.M., Ribeiro, C.C., Microbiological analysis after complete or partial removal of carious dentin in primary teeth: A randomized clinical trial (2009) Caries Res, 43 (5), pp. 354-358Weerheijm, K.L., Kreulen, C.M., De Soet, J.J., Groen, H.J., Van Amerongen, W.E., Bacterial counts in carious dentine under restorations: 2-year in vivo effects (1999) Caries Res, 33 (2), pp. 130-134Weng, Y., Guo, X., Gregory, R., Xie, D., A novel antibacterial dental glass-ionomer cement (2010) Eur J Oral Sci, 118 (5), pp. 531-534Hodrova, I., Clinical procedures with Caridex system (1990) ZWR, 99 (10), pp. 795-797. , [article in German]Magalhaes, C.S., Moreira, A.N., Campos, W.R.C., Rossi, F.M., Castilho, G.A.A., Ferreira, R.C., Effectiveness and efficiency of chemomechanical carious dentin removal (2006) Braz Dent J, 17 (1), pp. 63-6

Long-term evaluation of the stability of dentin matrix following treatments with aqueous solutions of titanium tetrafluoride at different concentrations

Objective: The purpose of this study was to investigate the effects of aqueous solutions of different concentrations of titanium tetrafluoride (TiF4) on dentin matrix stability up to six months

Chemical Composition and Microhardness of Human Enamel Treated with Fluoridated Whintening Agents. A Study in Situ

BACKGROUND: Dental whitening has been increasingly sought out to improve dental aesthetics, but may cause chemical and morphological changes in dental enamel surfaces. OBJECTIVE: Assess in situ the effects of high-concentration hydrogen peroxide with and without fluoride on human dental enamel using the ion chromatography test (IC) and the Knoop hardness test (KHN). MATERIAL AND METHODS: Nineteen enamel specimens were prepared using third human molars. These specimens were fixed on molars of volunteers and were divided into groups: OP38-Opalescence Boost PF38%, PO37-Pola Office 37.5% and CO-Control group. For chemical analysis (n= 3), the dentin layer was removed, keeping only the enamel, which was subjected to acidic digestion by microwave radiation. It was necessary to perform sample dilutions for the elements fluorine (F), calcium (Ca) and phosphorus (P) for quantification using the IC test. The KHN (n= 5) was performed before and after the treatments. Five indentations were made, separated by 100 µm, for each specimen using a load of 25 gf for 5 seconds in the microdurometer. The data were analyzed using ANOVA with a 5% significance level. RESULTS: The OP38 group had the largest concentrations of F, Ca and P ions. The PO37 group showed the lowest concentrations of F and Ca ions. The average KHN was not significantly different between the OP38 and PO37 groups. CONCLUSION: Enamel whitened with hydrogen peroxide containing fluoride had greater concentrations of F, Ca and P ions. The presence of fluoride in the whitening agent did not influence the enamel microhardness

TiO2 nanotubes improve physico-mechanical properties of glass ionomer cement

The aim of this study was to determine the physico-mechanical properties of a high viscosity glass ionomer cement (GIC) reinforced with TiO2 nanotubes (TiO2-nt). Methods: TiO2-nt was incorporated into the GIC powder components (Ketac Molar EasyMix™) in concentrations of 0% (control group), 3%, 5%, 7% by weight. Compressive strength (n = 10/group), three point bending for flexural strength (n = 18/group), microshear bond strength to dentin and failure mode (n = 20/group), and surface roughness and weight loss before and after brushing simulation (30,000 cycles) (n = 8/group) were evaluated. Data were submitted to Shapiro-Wilk, ANOVA, Tukey and Chi-square tests (α ≤ 0.05). Results: Addition of 5% of TiO2-nt into GIC presented the highest values for compressive strength and differed from the control, 3% and 7% groups (p = 0.023). There were no significant differences in flexural strength (p = 0.107) and surface roughness before and after the dental brushing (p = 0.287) among the groups. GIC added with 5% TiO2-nt showed the lowest weight loss values (p = 0.01), whereas the control, 3% or 5% TiO2-nt groups presented similar microshear bond strength values (p ≥ 0.05). The 5% TiO2-nt group featured higher microshear bond strength than the 7% TiO2-nt group (p = 0.034). Cohesive in material was the most representative failure mode for all groups. Significance: The incorporation of TiO2-nt did not affect GIC's adhesiveness to dentin, but improved its compressive strength at 5%. Furthermore, TiO2-nt decreased the percentage of weight loss after GIC's surface wear363e85e9