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Preventing contamination and white spot lesions
platelets become activated, even partially, the receptors become exposed so that they are sticky, binding to damaged endothelium or atherosclerotic plaque involving collagen, fibronectin, and von Willebrand factor. Partial platelet activation can occur with exposure to the peptide YFLLRNP; stronger or additive stimuli may increase the degree of activation. The aggregation of platelets is a key contributor to thromboembolytic disorders, so the unwarranted platelet activation from any source is undesirable. Traditionally it was proposed that the cumulative response mechanism of the host contributes substantially to the pathogenesis of periodontitis, which seems to be at work here. Whitaker EJ, Thomas IS, Falk JA, et al: Effect of acetylsalicylic acid on aggregation of human platelets by Porphyromonas gingivalis. Gen Dent Jan-Feb 2007, pp 64-69, 2007
Clinical Significance.—Discussed here is the nature of the relationship between periodontal and cardiovascular disease. Factors issuing from P gingivalis, a pathogen common in periodontitis, promote platelet aggregation. Once initiated this process promotes further clumping, with attachment of clumps to damaged endothelial walls. Suggested is that since ASA inhibits this initial aggregation, the process is shortcircuited by the reduced supply of clots to adhere to vessel walls. Reprints available from the Academy of General Dentistry. Fax your request to Jo Posselt (312/440-4261) or e-mail AGDJournal@agd. org
Orthodontics Preventing contamination and white spot lesions Background.—White-spot lesions are localized decalcifications of the enamel around a bonded bracket that occur within a few weeks after an orthodontic appliance is placed. About 50% to 96% of patients who undergo orthodontic treatment will develop white-spot lesions. Applying a polymer coating to the labial enamel tooth surface before bonding can reduce demineralization. Clinical conditions can interfere with the provision of the completely dry surface needed to achieve acceptable bond strengths. Even brief exposure to saliva or blood can adversely affect the bond strength. The effect of contamination with blood or saliva on the bond strength of a light-cured system used with a liquid polish (BisCover) was tested in vitro. Methods.—The 120 permanent human premolars were randomly assigned to 6 groups of 20 teeth each. Group 1 underwent bonding with a light-cured bonding system (Transbond XT) only; group 2 had BisCover polymeric resin applied to the etched tooth surfaces before bracket bonding with Transbond XT resin. A comparison of these 2 groups showed no significant difference, so
the remainder of the teeth were prepared without the Transbond XTresin (Table 1). Groups 3 and 5 were contaminated with blood or saliva, respectively, applied to the etched enamel, then BisCover was applied. Groups 4 and 6 were contaminated with blood or saliva, respectively, on BisCover-treated surfaces. A universal testing machine was used to apply shear forces for the measurement of bond strengths. Results.—The shear bond strengths of groups contaminated before the BisCover was applied were significantly less than those of groups contaminated after BisCover application (Table 3). The values for those groups contaminated after the BisCover application were comparable to those of group 2, which had no contamination. Groups with blood contamination had lower shear bond strength values than those with saliva contamination when the contamination occurred before the BisCover application. No significant difference in shear bond strength between the blood and saliva was noted when the contamination occurred after the BisCover application.
Table 1.—Bonding Procedures Group 1 Group 2 Group 3 Group 4 Group 5 Group 6
38% 38% 38% 38% 38% 38%
Phosphoric acid Phosphoric acid Phosphoric acid Phosphoric acid Phosphoric acid Phosphoric acid
Rinsing/drying Rinsing/drying Rinsing/drying Rinsing/drying Rinsing/drying Rinsing/drying
Dry Dry Blood Dry Saliva Dry
Primer—Transbond XT BisCover BisCover BisCover BisCover BisCover
Adhesive—Transbond Light-cure Light-cure Adhesive—Transbond Light-cure Light-cure Adhesive—Transbond Light-cure Light-cure Blood Adhesive—Transbond Light-cure Light-cure Adhesive—Transbond Light-cure Light-cure Saliva Adhesive—Transbond Light-cure
(This article was published in Am J Orthod Dentofacial Orthop, 131, Sayinsu K, Isik F, Sezen S, et al, Effect of blood and saliva contamination on bond strength of brackets and bonded with a protective liquid polish and a light-cured adhesive, 391-394, Copyright American Association of Orthodontics (2007).)
Volume 52
Issue 6
2007
353
Table 3.—Shear Bond Strength (MPa) and Results of 1-way ANOVA for Groups 2-6 Group 2 Group 3 Group 4 Group 5 Group 6 P value Significance
Mean
SD
Maximum
Minimum
13.33 4.95 12.34 9.24 13.28 .0001 *
2.51 2.35 2.05 1.93 2.61
18.38 10.14 15.48 12.44 17.70
10.18 1.45 9.14 5.25 8.31
(This article was published in Am J Orthod Dentofacial Orthop, 131, Sayinsu K, Isik F, Sezen S, et al, Effect of blood and saliva contamination on bond strength of brackets and bonded with a protective liquid polish and a lightcured adhesive, 391-394, Copyright American Association of Orthodontics (2007).) * P < .01.
Discussion.—Previous reports have found that when the acid-etched surface becomes wet, porosities are plugged, inhibiting the penetration of the resin and producing resin tags of insufficient numbers and lengths. Bond strength can be compromised with even momentary blood and saliva exposures. This study showed that blood contamination reduces bond strengths more than saliva contamination. The damaging effects of
contamination were limited, however, when BisCover was applied before contamination occurred. Successful bonding in the groups with the pre-exposure BisCover application was probably attributable to the light-curing of the bonding material producing sufficient numbers and lengths of resin tags.
Clinical Significance.—Previously advocated to help prevent white-spot lesions around orthodontic brackets, application of a polymer coating to etched enamel surfaces prior to bonding of orthodontic brackets was shown here to prevent degradation in shear bond strength from saliva or blood contamination.
Sayinsu K, Isik F, Sezen S, et al: Effect of blood and saliva contamination on bond strength of brackets bonded with a protective liquid polish and a light-cured adhesive. Am J Orthod Dentofacial Orthop 131:391-394, 2007 Reprints available from K Sayinsu, Faculty of Dentistry, Yeditepe Univ, Bagdat Cad No 238, Goztepe 34730, Istanbul, Turkey; e-mail: [email protected]
Pain and Pain Control Postoperative sensitivity and bonding agent Background.—Postoperative dental pain has recently been interpreted as a function of pulpal hydrodynamics. Sealing of the dentinal tubules is essential to avoid such pain. Agents that include an acidic primer may produce a better seal. Two groups of patients were studied using a standardized cold stimulus. In the treatment group, a self-priming resin (Z250 and Adper Prompt) requiring a separate etching step was used. In the control group, restorations were placed using a multistep system with a self-priming bonding agent (Z250 and Single Bond). It was expected that there would be no difference in sensitivity levels between the 2 groups. Methods.—This community-based, randomized, double-blind clinical trial included 209 restorations placed in 76 participants who were asymptomatic when the trial began. Within each group, the level of sensitivity 1, 2, and 13 weeks after restoration was tested and compared with the preoperative level of sensitivity. Participants rated the pain for each restored tooth using a visual analog scale (VAS) immediately after a standardized cold stimulus was applied. Results.—The VAS scores and the 3 different periods of evaluation showed a significant association (Table 2). After
354
Dental Abstracts
Table 2.—Median VAS Scores Evaluation Period
Preoperative n = 76 One-week n = 76 Two-week n = 76 Thirteen-week n = 76
Single Bond
Adper Prompt
21.00 18.75 4.00a 13.00a
22.75 18.00 6.75a 13.00a
(Courtesy of Browning WD, Blalock JS, Callan RS, et al: Postoperative sensitivity: A comparison of two bonding agents. Oper Dent 32:112-117, 2007.)
1 week, the VAS score did not differ significantly from the preoperative score. At the 13-week evaluation, the median sensitivity scores were significantly lower than preoperatively. Discussion.—Both dentin-bonding agents demonstrated an ability to reduce the patients’ sensitivity to a cold-water stimulus from the levels present preoperatively. Measurements obtained 13 weeks after the restorations were placed showed no difference between the restorations placed with a self-etching, self-priming dentin bonding agent and those placed with a self-priming dentin bonding agent that required an added etching step.
Clinical Significance.—Discussed here is the nature of the relationship between periodontal and cardiovascular disease. Factors issuing from P gingivalis, a pathogen common in periodontitis, promote platelet aggregation. Once initiated this process promotes further clumping, with attachment of clumps to damaged endothelial walls. Suggested is that since ASA inhibits this initial aggregation, the process is shortcircuited by the reduced supply of clots to adhere to vessel walls. Reprints available from the Academy of General Dentistry. Fax your request to Jo Posselt (312/440-4261) or e-mail AGDJournal@agd. org
Orthodontics Preventing contamination and white spot lesions Background.—White-spot lesions are localized decalcifications of the enamel around a bonded bracket that occur within a few weeks after an orthodontic appliance is placed. About 50% to 96% of patients who undergo orthodontic treatment will develop white-spot lesions. Applying a polymer coating to the labial enamel tooth surface before bonding can reduce demineralization. Clinical conditions can interfere with the provision of the completely dry surface needed to achieve acceptable bond strengths. Even brief exposure to saliva or blood can adversely affect the bond strength. The effect of contamination with blood or saliva on the bond strength of a light-cured system used with a liquid polish (BisCover) was tested in vitro. Methods.—The 120 permanent human premolars were randomly assigned to 6 groups of 20 teeth each. Group 1 underwent bonding with a light-cured bonding system (Transbond XT) only; group 2 had BisCover polymeric resin applied to the etched tooth surfaces before bracket bonding with Transbond XT resin. A comparison of these 2 groups showed no significant difference, so
the remainder of the teeth were prepared without the Transbond XTresin (Table 1). Groups 3 and 5 were contaminated with blood or saliva, respectively, applied to the etched enamel, then BisCover was applied. Groups 4 and 6 were contaminated with blood or saliva, respectively, on BisCover-treated surfaces. A universal testing machine was used to apply shear forces for the measurement of bond strengths. Results.—The shear bond strengths of groups contaminated before the BisCover was applied were significantly less than those of groups contaminated after BisCover application (Table 3). The values for those groups contaminated after the BisCover application were comparable to those of group 2, which had no contamination. Groups with blood contamination had lower shear bond strength values than those with saliva contamination when the contamination occurred before the BisCover application. No significant difference in shear bond strength between the blood and saliva was noted when the contamination occurred after the BisCover application.
Table 1.—Bonding Procedures Group 1 Group 2 Group 3 Group 4 Group 5 Group 6
38% 38% 38% 38% 38% 38%
Phosphoric acid Phosphoric acid Phosphoric acid Phosphoric acid Phosphoric acid Phosphoric acid
Rinsing/drying Rinsing/drying Rinsing/drying Rinsing/drying Rinsing/drying Rinsing/drying
Dry Dry Blood Dry Saliva Dry
Primer—Transbond XT BisCover BisCover BisCover BisCover BisCover
Adhesive—Transbond Light-cure Light-cure Adhesive—Transbond Light-cure Light-cure Adhesive—Transbond Light-cure Light-cure Blood Adhesive—Transbond Light-cure Light-cure Adhesive—Transbond Light-cure Light-cure Saliva Adhesive—Transbond Light-cure
(This article was published in Am J Orthod Dentofacial Orthop, 131, Sayinsu K, Isik F, Sezen S, et al, Effect of blood and saliva contamination on bond strength of brackets and bonded with a protective liquid polish and a light-cured adhesive, 391-394, Copyright American Association of Orthodontics (2007).)
Volume 52
Issue 6
2007
353
Table 3.—Shear Bond Strength (MPa) and Results of 1-way ANOVA for Groups 2-6 Group 2 Group 3 Group 4 Group 5 Group 6 P value Significance
Mean
SD
Maximum
Minimum
13.33 4.95 12.34 9.24 13.28 .0001 *
2.51 2.35 2.05 1.93 2.61
18.38 10.14 15.48 12.44 17.70
10.18 1.45 9.14 5.25 8.31
(This article was published in Am J Orthod Dentofacial Orthop, 131, Sayinsu K, Isik F, Sezen S, et al, Effect of blood and saliva contamination on bond strength of brackets and bonded with a protective liquid polish and a lightcured adhesive, 391-394, Copyright American Association of Orthodontics (2007).) * P < .01.
Discussion.—Previous reports have found that when the acid-etched surface becomes wet, porosities are plugged, inhibiting the penetration of the resin and producing resin tags of insufficient numbers and lengths. Bond strength can be compromised with even momentary blood and saliva exposures. This study showed that blood contamination reduces bond strengths more than saliva contamination. The damaging effects of
contamination were limited, however, when BisCover was applied before contamination occurred. Successful bonding in the groups with the pre-exposure BisCover application was probably attributable to the light-curing of the bonding material producing sufficient numbers and lengths of resin tags.
Clinical Significance.—Previously advocated to help prevent white-spot lesions around orthodontic brackets, application of a polymer coating to etched enamel surfaces prior to bonding of orthodontic brackets was shown here to prevent degradation in shear bond strength from saliva or blood contamination.
Sayinsu K, Isik F, Sezen S, et al: Effect of blood and saliva contamination on bond strength of brackets bonded with a protective liquid polish and a light-cured adhesive. Am J Orthod Dentofacial Orthop 131:391-394, 2007 Reprints available from K Sayinsu, Faculty of Dentistry, Yeditepe Univ, Bagdat Cad No 238, Goztepe 34730, Istanbul, Turkey; e-mail: [email protected]
Pain and Pain Control Postoperative sensitivity and bonding agent Background.—Postoperative dental pain has recently been interpreted as a function of pulpal hydrodynamics. Sealing of the dentinal tubules is essential to avoid such pain. Agents that include an acidic primer may produce a better seal. Two groups of patients were studied using a standardized cold stimulus. In the treatment group, a self-priming resin (Z250 and Adper Prompt) requiring a separate etching step was used. In the control group, restorations were placed using a multistep system with a self-priming bonding agent (Z250 and Single Bond). It was expected that there would be no difference in sensitivity levels between the 2 groups. Methods.—This community-based, randomized, double-blind clinical trial included 209 restorations placed in 76 participants who were asymptomatic when the trial began. Within each group, the level of sensitivity 1, 2, and 13 weeks after restoration was tested and compared with the preoperative level of sensitivity. Participants rated the pain for each restored tooth using a visual analog scale (VAS) immediately after a standardized cold stimulus was applied. Results.—The VAS scores and the 3 different periods of evaluation showed a significant association (Table 2). After
354
Dental Abstracts
Table 2.—Median VAS Scores Evaluation Period
Preoperative n = 76 One-week n = 76 Two-week n = 76 Thirteen-week n = 76
Single Bond
Adper Prompt
21.00 18.75 4.00a 13.00a
22.75 18.00 6.75a 13.00a
(Courtesy of Browning WD, Blalock JS, Callan RS, et al: Postoperative sensitivity: A comparison of two bonding agents. Oper Dent 32:112-117, 2007.)
1 week, the VAS score did not differ significantly from the preoperative score. At the 13-week evaluation, the median sensitivity scores were significantly lower than preoperatively. Discussion.—Both dentin-bonding agents demonstrated an ability to reduce the patients’ sensitivity to a cold-water stimulus from the levels present preoperatively. Measurements obtained 13 weeks after the restorations were placed showed no difference between the restorations placed with a self-etching, self-priming dentin bonding agent and those placed with a self-priming dentin bonding agent that required an added etching step.