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Temperature effect on fluoride release
Fluoride Temperature effect on fluoride release Background.—Glass ionomer cements (GICs) are the most successful of the materials designed to release fluoride. GICs are active throughout the life of a restoration and react with the oral environment in a unique way. The fluoride release of GICs can vary depending on several factors. It can be improved by recharging from a fluoride source applied in the oral environment. Temperature fluctuations have not previously been analyzed for their effect on fluoride release by GICs. It was hypothesized that environmental temperature may influence not only fluoride release but the recharging ability of GICs. Methods.—Five disk-shaped specimens were formed of each of the materials tested. All the materials were capsulated glass ionomers and included Ketac Cem Maxicap, a conventional luting GIC; Ketac Molar Aplicap and Fuji IX GP Fast, both high-viscosity restorative GICs; and Fuji II LC Capsule, a restorative resin-modified GIC (Table 1). The fluoride released by each material was measured at 4 C, 37 C, and 55 C. In addition, 3 groups of specimens were stored in water for 30 days before recharging at these same temperatures for 5 minutes. Fluoride release was measured each day beginning 2 days before recharging until 2 days after the process. Results.—The luting GIC had the greatest release and recharging of fluoride at all testing temperatures. The resin-modified GIC was next, then the high-viscosity GICs. Both the fluoride release and the recharging ability increased as the temperature rose (Fig 7).
Fig 7.—Twenty-four hour fluoride re-release (mg/cm2) after recharging at 4 C (A), 37 C (B), and 55 C (C). For each material, the 24-hour fluoride re-release after recharging at 55 C was greater than at 4 C and 37 C, but significant difference (P < .05) was only observed in KM, F, and FLC. Abbreviations: KM, Ketac Molar Aplicap; F, Fuji IX GP Fast; FLC, Fuji II LC Capsule. (Courtesy of Yan Z, Sidhu SK, Mahmoud GA, et al: Effects of temperature on the fluoride release and recharging ability of glass ionomers. Oper Dent 32:138-143, 2007.)
Discussion.—Increased environmental temperature produced increased fluoride release and recharging ability for all the GICs tested. Thus using a higher temperature during fluoride application may increase the fluoride recharging of GIC achieved as well as its ability to release fluoride. Lower oral temperatures are not conducive to optimal fluoride recharging or release.
Table 1.—Materials Used in This Study and Their Composition Product
Type of Materialsy
Ketac Cem Maxicap (KC)
Conventional luting glass ionomer
Ketac Molar Alicap (KM)
High viscosity restorative glass ionomer
Fuji IX (F)
High viscosity restorative glass ionomer
Fuji II LC (FLC)
Resin-modified restorative glass ionomer
Composition (manufacturers information)
Batch #
Powder: fluoroaluminosilicate glass. Liquid: aqueous polycarboxylic acid. Powder: fluoroaluminosilicate glass. Liquid: aqueous polycarboxylic acid. Powder: strontium fluoroaluminosilicate glass. Liquid: aqueous polycarboxylic acid. Powder: fluoroaluminosilicate glass. Liquid: aqueous solution of poiycarboxylic acid, TEGDMA and HEMA
151394 126978 0312241 0401165
Abbreviations: HEMA, Hydroxyethylmethacrylate; TEGDMA, triethyleneglycol demethacrylate. (Courtesy of Yan Z, Sidhu SK, Mahmoud GA, et al: Effects of temperature on the fluoride release and recharging ability of glass ionomers. Oper Dent 32:138-143, 2007.)
Volume 52
Issue 6
2007
345
Clinical Significance.—How materials are manipulated can be as important as which materials are selected in achieving optimal restorative results. In this in vitro study the capacity of various forms of glass ionomer materials to take up and release fluoride was shown to be temperature sensitive. How to exploit this finding clinically needs to be explored further.
Yan Z, Sidhu SK, Mahmoud GA, et al: Effects of temperature on the fluoride release and recharging ability of glass ionomers. Oper Dent 32:138-143, 2007 Reprints available from Z Yan, Framlington Pl, Newcastle upon Tyne, NE2 4BW, United Kingdom; e-mail: [email protected]
Infection Control Antibacterial action of chloroform Background.—Persistent intracanal infection is the most common cause of failure of root canal treatment. The organism most often found is Enterococcus faecalis. Retreatment is generally performed when the initial root canal treatment is unsuccessful and depends on the ability to eliminate persistent bacteria using adequate chemomechanical preparation. Obturation materials must be removed. Chloroform is used to soften gutta-percha filling material during endodontic retreatment. Whether the chloroform can also kill bacteria in the canal was investigated. Methods.—The 23 matched pairs of teeth were extracted maxillary and mandibular anterior and bicuspid human teeth with mature apices and single root canals. After cleansing and instrumentation, the specimens were infected with E faecalis and obturated. Removal of the gutta-percha was performed using chloroform or saline solution. After removal and further apical enlargement, bacterial samples were obtained and compared between the specimens. Results.—Nineteen pairs were available for evaluation: 17 in the experimental group and 2 serving as controls. A significant difference in the colony-forming units was demonstrated between the samples treated with chloroform and those treated with saline solution. In the first bacterial sampling, 11 of the 17 samples treated with chloroform had negative cultures; none of the samples treated with saline
solution had negative cultures. In the second bacterial sampling, 9 of the 17 chloroform samples and 1 of the 17 saline solution samples had negative cultures. Discussion.—Use of chloroform to soften the guttapercha for removal reduced bacterial levels significantly more effectively than saline solution. Chloroform clearly showed it has antibacterial activity against the levels of E faecalis found in infected root canals.
Clinical Significance.—Bacterial contamination is a leading factor in failed root canal fillings. Eliminating contamination is essential for successful retreatment. In this study, chloroform, used to dissolve the old gutta-percha filling, was also demonstrated effective in eliminating E faecalis–a happy coincidence.
Edgar SW, Marshall JG, Baumgartner JC: The antimicrobial effect of chloroform on Enterococcus faecalis after gutta-percha removal. J Endod 32:1185-1187, 2006 Reprints available from JC Baumgartner, Dept of Endodontology, OHSU School of Dentistry, 611 SW Campus Dr, Portland, OR 97201; e-mail: [email protected]
Intracanal medicaments vs Enterococcus faecalis Background.—The usual choices for intracanal medicaments are sodium hypochlorite (5.25% NaOCl), BioPure MTAD, and chlorhexidine (2% CHX). All have proved useful for this purpose, but the search has continued for the ideal
346
Dental Abstracts
agent. Superoxidized waters inactivate many microorganisms in addition to those associated with endodontic infections. Dermacyn is a superoxidized water used in medical settings as a wound cleanser and demonstrates broad-
Fig 7.—Twenty-four hour fluoride re-release (mg/cm2) after recharging at 4 C (A), 37 C (B), and 55 C (C). For each material, the 24-hour fluoride re-release after recharging at 55 C was greater than at 4 C and 37 C, but significant difference (P < .05) was only observed in KM, F, and FLC. Abbreviations: KM, Ketac Molar Aplicap; F, Fuji IX GP Fast; FLC, Fuji II LC Capsule. (Courtesy of Yan Z, Sidhu SK, Mahmoud GA, et al: Effects of temperature on the fluoride release and recharging ability of glass ionomers. Oper Dent 32:138-143, 2007.)
Discussion.—Increased environmental temperature produced increased fluoride release and recharging ability for all the GICs tested. Thus using a higher temperature during fluoride application may increase the fluoride recharging of GIC achieved as well as its ability to release fluoride. Lower oral temperatures are not conducive to optimal fluoride recharging or release.
Table 1.—Materials Used in This Study and Their Composition Product
Type of Materialsy
Ketac Cem Maxicap (KC)
Conventional luting glass ionomer
Ketac Molar Alicap (KM)
High viscosity restorative glass ionomer
Fuji IX (F)
High viscosity restorative glass ionomer
Fuji II LC (FLC)
Resin-modified restorative glass ionomer
Composition (manufacturers information)
Batch #
Powder: fluoroaluminosilicate glass. Liquid: aqueous polycarboxylic acid. Powder: fluoroaluminosilicate glass. Liquid: aqueous polycarboxylic acid. Powder: strontium fluoroaluminosilicate glass. Liquid: aqueous polycarboxylic acid. Powder: fluoroaluminosilicate glass. Liquid: aqueous solution of poiycarboxylic acid, TEGDMA and HEMA
151394 126978 0312241 0401165
Abbreviations: HEMA, Hydroxyethylmethacrylate; TEGDMA, triethyleneglycol demethacrylate. (Courtesy of Yan Z, Sidhu SK, Mahmoud GA, et al: Effects of temperature on the fluoride release and recharging ability of glass ionomers. Oper Dent 32:138-143, 2007.)
Volume 52
Issue 6
2007
345
Clinical Significance.—How materials are manipulated can be as important as which materials are selected in achieving optimal restorative results. In this in vitro study the capacity of various forms of glass ionomer materials to take up and release fluoride was shown to be temperature sensitive. How to exploit this finding clinically needs to be explored further.
Yan Z, Sidhu SK, Mahmoud GA, et al: Effects of temperature on the fluoride release and recharging ability of glass ionomers. Oper Dent 32:138-143, 2007 Reprints available from Z Yan, Framlington Pl, Newcastle upon Tyne, NE2 4BW, United Kingdom; e-mail: [email protected]
Infection Control Antibacterial action of chloroform Background.—Persistent intracanal infection is the most common cause of failure of root canal treatment. The organism most often found is Enterococcus faecalis. Retreatment is generally performed when the initial root canal treatment is unsuccessful and depends on the ability to eliminate persistent bacteria using adequate chemomechanical preparation. Obturation materials must be removed. Chloroform is used to soften gutta-percha filling material during endodontic retreatment. Whether the chloroform can also kill bacteria in the canal was investigated. Methods.—The 23 matched pairs of teeth were extracted maxillary and mandibular anterior and bicuspid human teeth with mature apices and single root canals. After cleansing and instrumentation, the specimens were infected with E faecalis and obturated. Removal of the gutta-percha was performed using chloroform or saline solution. After removal and further apical enlargement, bacterial samples were obtained and compared between the specimens. Results.—Nineteen pairs were available for evaluation: 17 in the experimental group and 2 serving as controls. A significant difference in the colony-forming units was demonstrated between the samples treated with chloroform and those treated with saline solution. In the first bacterial sampling, 11 of the 17 samples treated with chloroform had negative cultures; none of the samples treated with saline
solution had negative cultures. In the second bacterial sampling, 9 of the 17 chloroform samples and 1 of the 17 saline solution samples had negative cultures. Discussion.—Use of chloroform to soften the guttapercha for removal reduced bacterial levels significantly more effectively than saline solution. Chloroform clearly showed it has antibacterial activity against the levels of E faecalis found in infected root canals.
Clinical Significance.—Bacterial contamination is a leading factor in failed root canal fillings. Eliminating contamination is essential for successful retreatment. In this study, chloroform, used to dissolve the old gutta-percha filling, was also demonstrated effective in eliminating E faecalis–a happy coincidence.
Edgar SW, Marshall JG, Baumgartner JC: The antimicrobial effect of chloroform on Enterococcus faecalis after gutta-percha removal. J Endod 32:1185-1187, 2006 Reprints available from JC Baumgartner, Dept of Endodontology, OHSU School of Dentistry, 611 SW Campus Dr, Portland, OR 97201; e-mail: [email protected]
Intracanal medicaments vs Enterococcus faecalis Background.—The usual choices for intracanal medicaments are sodium hypochlorite (5.25% NaOCl), BioPure MTAD, and chlorhexidine (2% CHX). All have proved useful for this purpose, but the search has continued for the ideal
346
Dental Abstracts
agent. Superoxidized waters inactivate many microorganisms in addition to those associated with endodontic infections. Dermacyn is a superoxidized water used in medical settings as a wound cleanser and demonstrates broad-