Bleaching effect of sodium percarbonate on discolored pulpless teeth in vitro

The purpose of this study was to evaluate the bleaching effect of sodium percarbonate on artificially stained pulpless teeth. Twenty extracted human mandibular premolars were stained by immersing them in human blood mixed with iron sulfide, and divided into three test groups and one control group. The following bleaching agents were used: sodium perborate mixed with 30% hydrogen peroxide (WB), sodium percarbonate mixed with distilled water (PW) or 30% hydrogen peroxide (PH). On days 5, 10, and 15, each pulp chamber was refilled with fresh bleaching paste. The L* (average lightness) of the midbuccal area of specimens was measured before and after staining, and on days 5, 10, 15, and 20 by colorimeter. The bleaching effect was evaluated by the lightness recovery rate (LRR) calculated from L*. WB showed the highest LRR among all groups, and PW and PH showed significantly higher LRR when compared with the control group. PW and PH were not significantly different. Results showed that sodium percarbonate had an obvious bleaching effect without hydrogen peroxide and indicated that it could be a safe intracoronal bleaching agent.     

Intracoronal bleaching of discolored non-vital teeth

This clinical study compared the effectiveness of bleaching non-vital teeth with an open pulp chamber during bleaching using 10% carbamide peroxide compared to the modified walking bleach technique and extracoronal bleaching. Sixty discolored, non-vital teeth were treated. They were divided into three groups. Each group was treated with one of the bleaching materials and methods: extracoronally using 10% carbamide peroxide for two weeks as negative control (Group A), intracoronally using sodium perborate mixed with 3% hydrogen peroxide (modified walking bleach technique) (Rotstein, Mor & Friedman, 1993) for four weeks (Group B) and intracoronally and extracoronally using 10% carbamide peroxide for two weeks (Group C) (Liebenberg, 1997). Tooth color was measured at baseline, (BL), immediately post-bleaching (IP) and six months post-bleaching (SP) with a colorimeter (Castor, Sigma, Germany) using a tooth-positioning jig. The color was determined according to the CIELAB system, which records lightness as L* and chromaticity coordinates as a* and b*. The difference in L* and b* among the three groups was significant between BL and IP examination. The post-bleaching, whitening effect in Group C was significantly better, but after six months, in Group C, it was as effective as in Group B.     

无髓变色牙内漂白113例疗效观察

目的 评价应用Beyond冷光美白和30％过氧化氢加过硼酸钠漂白技术对无髓变色牙进行牙内漂白的临床疗效.方法 无髓变色牙患者113例随机分为3组,分别采用30％过氧化氢加过硼酸钠(A组)、Beyond冷光美白技术(B组)、Beyond冷光美白技术复合常规内漂白(C组)进行牙内漂白,观察其有效率.结果 第1次复诊时有效率,A组29.7％,B组48.6％,C组68.4％,C组有效率高于另A、B组(P＜0.05).第6次复诊时有效率,A组54.1％,B组76.3％,C组97.3％,C组有效率高于另A、B组(P＜0.05).牙齿变色后与开始牙内漂白的时间间隔越短,达到满意疗效的治疗次数越少,A、B、C组平均治疗次数分别为16次、12次和7次.结论 Beyond冷光美白技术复合常规牙内漂白对无髓变色牙有显著增白作用,常规Beyond冷光美白次之,30％过氧化氢加过硼酸钠漂白技术牙内漂白效果较差.     

External root resorption following bleaching of pulpless teeth with oxygen peroxide

Abstract Eleven teeth in which bleaching with 30% oxygen peroxide was followed by external root resorption are presented. One tooth had no traumatic history, while the others were previously subluxated or luxated in accidental injury. Radiographic appearance of resorptions varied. In 2 teeth the resorptions were only superficial and did not progress during the observation time. In 5 teeth the resorptions were associated with ankylosis. In the remaining 4 teeth the resorption was progressive, bowl-shaped and associated with radiolucency in the adjacent alveolar bone. It was suggested that damage to the periodontium, caused by oxygen peroxide at the time of treatment, may heal or be followed by ankylosis and, when complicated by bacterial contamination, develop to a progressive root resorption associated with persistent inflammatory changes in periodontal tissues.     

In vitro assessment of a gel base containing 2% chlorhexidine as a sodium perborate's vehicle for intracoronal bleaching of discolored teeth

The purpose of this study was to assess a gel base containing 2% chlorhexidine (CHX) as a vehicle to be mixed with sodium perborate for intracoronal bleaching of discolored teeth, comparing its bleaching efficacy to sodium perborate mixed with other vehicles; 37% carbamide peroxide and 30% hydrogen peroxide. There were 110 fresh bovine incisors artificially stained using whole blood. The samples were divided into 11 groups and the intracoronal bleaching was performed using the "walking bleach technique". The bleaching agents were replaced three times at 7-day intervals. Using digital photos and a shade guide created for bovine teeth, the samples were evaluated at day 0, 7, 14, 21, and 28. On evaluation day, the photos were examined by three endodontists giving scores from 1 to 5 based on the shade guide created. Data were analyzed statistically by Kruskall-Wallis test. After 28 days, all evaluated teeth received scores that were statistically similar. Groups that used sodium perborate and a liquid vehicle bleached faster than those that used a gel based vehicle. The CHX gel allowed dissociation for the bleaching agent. The 2% CHX gel exhibited a good potential for use as a vehicle for sodium perborate or as a complement for carbamide peroxide.     

Beyond冷光美白术对无髓变色牙的临床疗效观察

目的:评价应用Beyond冷光美白技术采用内外联合漂白方式对无髓变色牙的临床疗效。方法:选择牙齿变色病人180例,随机分成3组,分别采用内漂白、外漂白、内外联合漂白技术进行治疗,观察其有效率;对进行内外联合漂白的外伤变色牙的外伤时间和漂白次数进行统计分析。结果:1周后,内外联合漂白有效率达到95%,4周后,内外联合漂白有效率达到98.3%,与其他组相比均具有统计学意义;外伤导致牙齿变色并进行内外联合漂白的病人,外伤时间与漂白次数成正比。结论:Beyond冷光美白技术采用内外联合漂白方式对无髓变色牙有明显的增白作用。     

In vitro efficacy of sodium perborate preparations used for intracoronal bleaching of discolored non-vital teeth

Abstract Bleaching materials containing 30% hydrogen peroxide have been used successfully for the treatment of discolored non–vital teeth. Intracoronal application of these materials was occasionally associated with the development of external root resorption. Extracted human teeth with intact crowns were discolored in vitro and bleached with three preparations of sodium perborate. These preparations included: sodium perborate with 30% hydrogen peroxide, sodium perborate with 3% hydrogen peroxide and sodium perborate with water. The bleaching materials were placed in the pulp chamber of the discolored teeth and sealed with IRM for 14 days. They were replaced with fresh preparations after 3 and 7 days. The coronal tooth shades were evaluated after 3, 7 and 14 days and a comparison of the bleaching success of the groups was made at each interval. It was found that after 14 days and three bleachings there was no significant difference in success between the groups. It is therefore recommended that sodium perborate be used in combination with water rather than with hydrogen peroxide to reduce the risk of post-bleaching external root resorption.     

In vitro efficacy of sodium perborate preparations used for intracoronal bleaching of discolored non-vital teeth

Bleaching materials containing 30% hydrogen peroxide have been used successfully for the treatment of discolored non-vital teeth. Intracoronal application of these materials was occasionally associated with the development of external root resorption. Extracted human teeth with intact crowns were discolored in vitro and bleached with three preparations of sodium perborate. These preparations included: sodium perborate with 30% hydrogen peroxide, sodium perborate with 3% hydrogen peroxide and sodium perborate with water. The bleaching materials were placed in the pulp chamber of the discolored teeth and sealed with IRM for 14 days. They were replaced with fresh preparations after 3 and 7 days. The coronal tooth shades were evaluated after 3, 7 and 14 days and a comparison of the bleaching success of the groups was made at each interval. It was found that after 14 days and three bleachings there was no significant difference in success between the groups. It is therefore recommended that sodium perborate be used in combination with water rather than with hydrogen peroxide to reduce the risk of post-bleaching external root resorption.     

External cervical resorption after bleaching a pulpless tooth

A tooth with cervical resorption possibly caused by an internal bleaching technique was treated with calcium hydroxide. This case had characteristics in common with the other seven cases that have been described in the literature. Several possible treatment methods are discussed, along with the speculation that internal bleaching of tetracycline-discolored teeth may lead to cervical resorption.     

In vitro comparison of bleaching agents on the crowns and roots of discolored teeth

Sixty teeth were stained in vitro to compare the decolorizing effect of three bleaching agents on the crowns and on the roots of teeth containing an intracoronal isolating base. With an intracoronal isolating base placed either at the cementoenamel junction (CEJ) or 2-mm below the CEJ, bleaching agents of Superoxol, sodium perborate, and a combination of the two were placed in the pulp chamber of teeth and the accesses sealed with IRM. Customized shade guides were used to evaluate the color changes of the crowns and roots. After three treatments, the combination technique was found to be more effective in decolorizing the crowns and roots of teeth than Superoxol or sodium perborate alone (p less than 0.05). No difference was found between the Superoxol group and the sodium perborate group. There was no difference in color shades of crowns in which the IRM base was placed either at the CEJ or 2-mm below the CEJ. The roots of all groups showed some degree of decoloration. Based on the bleaching effects on discolored roots, the effectiveness of this seal is questionable.