Effects of chlorhexidine gluconate as an endodontic irrigant on the apical seal: short-term results.

The aim of this study was to ascertain whether chlorhexidine gluconate (0.12%), used as an endodontic irrigating solution would affect the apical seal obtained when using three different root canal cements. One hundred extracted human single-canal teeth were divided into 9 experimental groups of 10 teeth each and a positive and negative group of 5 teeth each. The teeth were decoronated at the level of the cementoenamel junction, then accessed, instrumented to a Master Apical File #50, irrigated with either sterile saline, 5.25% NaOCl or 0.12% chlorhexidine gluconate, and dried using paper points. Obturation was accomplished using lateral condensation and 1 of 3 endodontic sealers: Roth's 811, AH26, or Sealapex. At 90 and 180 days after obturation apical leakage was measured using the fluid filtration method. Using the ANOVA test the results showed no significant difference in seal related to the irrigant at both the 90- and 180-day observation periods.     

根管治疗失败原因的临床分析

目的：探讨根管治疗失败的原因。方法：按纳入标准选取206名患者，分析根管治疗失败患牙215颗，根据初次治疗情况、临床检查、术前X线片以及术中对患牙根管系统的探查等判断原治疗失败的原因。结果：失败病例中慢性根尖周炎患牙最多，占67．9％，其次是无根尖暗影、但因欠充要求再治疗的患牙，以及存在冠渗漏的患牙；X线片显示84．2％的患牙欠充，多数后牙根管锥度欠佳；遗漏根管多见于上颌第一磨牙和前磨牙；18．1％的患牙存在台阶、根管偏移等并发症。结论：因预备和充填不当等造成的根管清理不彻底、封闭不严密使根管系统再感染是根管治疗失败的主要原因，遗漏根管、冠部渗漏等也可造成治疗失败。     

牙髓治疗失败的原因分析

目的:通过对临床上牙髓治疗失败需再治疗的病例进行分析,探讨牙髓治疗失败的原因。方法:选取牙髓治疗失败患牙236个,根据初次治疗情况、临床检查、术前X线片以及术中对患牙根管系统的探查等,判断原治疗失败的原因。结果:83.7%的干髓术患牙存在根尖周病变;塑化治疗失败的患牙中,以无根尖周病变但发生牙折最多见,占57.1%,其次为塑化不全造成根尖周炎或残髓炎;根管治疗失败的患牙,58.5%存在根尖周病变,85.1%的患牙欠充且根管形态欠佳,14.9%的患牙存在台阶、根管偏移等并发症。结论:干髓术疗效差,多数失败患牙存在根尖周炎;塑化治疗失败的原因多为牙折或塑化不全;因预备和充填不完善等因素造成的根管清理不彻底、封闭不严密,使根管系统再感染是根管治疗失败的主要原因。     

Effect of 2% chlorhexidine gel as an intracanal medication on the apical seal of the root-canal system

The purpose of this study was to determine what effect intracanal medications might have on the apical seal of the root-canal system. Forty-two teeth were cleaned and shaped in a crown-down manner to a size #50 K-file. The teeth were divided into three groups: (A) immediate obturation; (B) intracanal placement of calcium hydroxide placed for 14 days; and (C) 2% chlorhexidine gel placed for 14 days. After 14 days, these materials were removed using copious irrigation and obturation was completed on groups B and C. Obturation was performed using the continuous wave of condensation technique using AH Plus sealer in all groups. Leakage was evaluated 60 days after obturation by using a fluid-filtration device. Using the one-way ANOVA test, there was no statistically significant difference in leakage between the three groups. Under the conditions of this study, 2% chlorhexidine gel and calcium hydroxide paste did not adversely affect the apical seal of the root-canal system.     

Effect of immediate dowel space preparation on the apical seal of endodontically filled teeth.

The purpose of this study was to investigate in vitro the effect of using hot endodonic pluggers for immediate dowel space preparation on the apical seal of endodontically treated teeth filled by a chloropercha technique. The results demonstrated that, when the coronal half of the root canal filling material was removed immediately after placement with pluggers, there was a loss of the apical seal and leakage in thirteen of twenty teeth. There was also leakage in thirteen of twenty teeth in which dowel spaces were not prepared. This study did not demonstrate a significant difference statistically in loss of apical seal and leakage between teeth prepared with and those without immediate dowel space preparations with pluggers using a chloropercha filling technique. Immediate preparation of the dowel spaces had no effect on the apical seal. The chloropercha technique by itself showed evidence of very high leakage when used to fill the root canal.     

Apical leakage of resin based root canal sealers with a new computerized fluid filtration meter

In this in vitro study, the apical leakage of three root-canal sealers: AH Plus, Diaket, and EndoREZ was evaluated using a new computerized fluid filtration meter. Forty-five extracted human premolar teeth with single root and canal were used. The coronal part of each tooth was removed and the root canals were prepared using GT Rotary files and crown-down technique. The roots were randomly divided into three groups of 15 samples, filled with one of the test materials and gutta-percha cones by the cold lateral condensation technique and were stored at 37 degrees C and 100% humidity for 7 days. One-week later, apical parts of roots of 10 +/- 0.05 mm were attached to computerized fluid filtration meter. Apical leakage quantity was determined as microl/cmH(2)O/min(-1). Statistical analysis indicated that root fillings with Diaket in combination with cold lateral condensation technique showed lower apical leakage than the others (p < 0.05). In addition, this new computerized fluid filtration meter allowed quantitative measurement of leakage easily. As it is a newly developed device to measure apical leakage of endodontic sealers, the reliability of it needed to be tested.     

Evaluation of the effect of endodontic irrigation solutions on the microhardness and the roughness of root canal dentin

The purpose of this study was to evaluate the effect of 0.2% chlorhexidine gluconate on the microhardness and roughness of root canal dentin compared with widely used irrigation solutions. Ninety, mandibular, anterior teeth extracted for periodontal reasons were used. The crowns of the teeth were removed at the CEJ. The roots were separated longitudinally into two segments, embedded in acrylic resin, and polished. A total of 180 specimens were divided into 6 groups of 30 teeth at random according to the irrigation solution used: group 1: 5.25% NaOCl for 15 min; group 2: 2.5% NaOCl for 15 min; group 3: 3% H2O2 for 15 min; group 4: 17% EDTA for 15 min; group 5: 0.2% chlorhexidine gluconate for 15 min; and group 6: distilled water (control). Each group was then divided into 2 subgroups of 15 specimens: groups 1a, 2a, 3a, 4a, 5a, and 6a were submitted to Vickers microhardness indentation tests; groups 1b, 2b, 3b, 4b, 5b, and 6b were used for determination of the roughness of root dentin. The data were recorded as Vickers numbers and Ra, microm for roughness test. The results were analyzed statistically by using one-way ANOVA and Tukey tests. The results indicated that all the irrigation solutions except chlorhexidine significantly decreased microhardness of root canal dentin (p < 0.05); 3% H2O2 and 0.2% chlorhexidine gluconate had no effect on roughness of the root canal dentin (p > 0.05). Although there are many other factors for irrigation solution preference, according to the results of this study, 0.2% chlorhexidine gluconate seems to be an appropriate endodontic irrigation solutions because of its harmless effect on the microhardness and roughness of root canal dentin.     

Influence of root canal dressings and sealers on repair of apical periodontitis after endodontic treatment

OBJECTIVE: The objective of this study was to evaluate the histopathologic response of periapical tissues after root canal treatment of necrotic dog teeth with chronic apical periodontitis by using 2 calcium hydroxide-based root canal dressings and 2 root canal sealers. STUDY DESIGN: Seventy-eight root canals were instrumented by using 5.25% sodium hypochlorite as the irrigating solution, after which a calcium hydroxide paste (Calen/PMCC or Calasept) was placed for 30 days as a dressing. The root canals were then filled by using cold lateral gutta-percha condensation and an endodontic sealer (Sealapex or AH Plus). After 360 days, the animals were killed by anesthetic overdose; then, the teeth were histologically prepared, sectioned, and stained with hematoxylin and eosin for optical microscopic analysis of apical and periapical tissue repair. RESULTS: Statistical analysis showed that the poorest histopathologic results were observed in the Calasept/AH Plus group and that the Sealapex sealer overall resulted in better apical repair than the AH Plus sealer. The histopathologic results of Calen/PMCC paste with both AH Plus and Sealapex and Calasept paste with only Sealapex were statistically similar but were different from the results of Calasept with AH Plus. CONCLUSIONS: The results of this study in the dog showed differences in apical and periapical tissue repair of teeth with chronic apical periodontitis by using 2 calcium hydroxide root canal dressings and 2 sealers. More research is necessary to determine the best combination of dressings and sealers.     

The effect of post space preparation on the apical seal of root fillings using chemically adhesive materials

The effect on the apical seal of root filling teeth with two sealer cements that reacted chemically with tooth structure was studied in vitro. In addition, apical leakage of teeth obturated with these materials and subsequently prepared to accept a post was tested. Ninety single-rooted teeth with mature apices were prepared chemomechanically by the stepback technique using files and copious irrigation with 2.5 per cent sodium hypochlorite. The teeth were then randomly allocated to six groups of 15 teeth each. Two groups were root filled by lateral condensation of gutta-percha and one of three sealer cements: Tubliseal, a radiopaque glass ionomer luting cement, Ketac Cem, and a chemically active composite resin, Panavia Ex. Thirty minutes later, in one group for each material, a post space was prepared leaving 4-5 mm of root filling at the apex. The extent of apical leakage in each group was determined after immersion in Indian ink for 14 days. The teeth were demineralized, dehydrated and immersed in methyl salicylate, which rendered them transparent, and a linear measurement of dye penetration was recorded. No statistically significant difference in the extent of leakage was found between the sealers in those groups which were filled by lateral condensation and left intact. However, the degree of leakage increased after post space preparation with the glass ionomer and Tubliseal groups, but was reduced in the Panavia Ex group.     

Effectiveness of three endodontic irrigants at various tubular depths in human dentin

Bacteria from infected root canals can invade dentinal tubules, thus dentin disinfection is an important aspect of endodontic therapy. This study compares three endodontic irrigants for efficiency in killing bacteria established within human dentinal tubules. Root canals in extracted teeth were prepared and sterilized. Broth cultures of Enterococcus faecalis were allowed to grow within the canals to penetrate dentinal tubules. The infected canals were exposed individually to each of the irrigants for 1 min. Irrigants were 0.525% sodium hypochlorite, Tubulicid (0.2% EDTA), and 0.12% chlorhexidine (Peridex). Sterile water was the control. Viable bacteria were analyzed by drilling incrementally into dentin from the cementum toward the canal. Smaller diameter drills were used for each depth. Shavings were cultured at three depths, for each of three root levels: coronal, midroot, and apical. Although considerable variation occurred between roots, sodium hypochlorite seemed to be superior. Tubulicid and Peridex were better than water. More bacteria remained viable at greater distances from the pulp. These observations apparently apply to all levels in the canal.     

Discuss that the coronal seal is more important than the apical seal for endodontic success

One of the main principles for successful root canal treatment is the prevention of microorganisms and toxins from the oral flora penetrating through the root canal system into the periapical tissues (1). This is achieved by obturating the root canal system completely, including the coronal and apical ends. Inadequate obturation of the root canal system has been found to be the most frequent cause of failure after endodontic treatment (2). A number of studies have indicated that leakage, whether from a coronal or apical direction, adversely affects the success of root canal treatment (3-7). The significance of the coronal seal has been increasingly recognized in the dental literature (4, 5, 8, 9) and in more recent times, it has been suggested that apical leakage may not be the most important factor leading to the failure of endodontic treatment--but that coronal leakage is far more likely to be the major determinant of clinical success or failure (10). This paper will discuss aspects of: endodontic success and failure; the use of leakage studies to assess the quality of the seal; the significance of both apical and coronal leakage; followed by a review of the literature.     

In vitro assessment of the antimicrobial action and the mechanical ability of chlorhexidine gel as an endodontic irrigant

The objective of this study was to assess the chlorhexidine gluconate gel as an endodontic irrigant. First the ability of chlorhexidine gel to disinfect root canals contaminated in vitro with Enterococcus faecalis was investigated. A scanning electron microscope was also used to evaluate its cleansing ability compared with endodontic irrigants commonly used, such as sodium hypochlorite and chlorhexidine gluconate liquid. The results indicated that the chlorhexidine gel produced a cleaner root canal surface and had an antimicrobial ability comparable with that obtained with the other solutions tested. It was concluded that chlorhexidine gluconate in gel form has potential for use as an endodontic irrigant.     

Effect of medications for root canal treatment on bonding to root canal dentin

Use of resin-based restorative materials recently has become widely accepted for treatment of endodontically treated teeth. However, some solutions routinely used during endodontic treatment procedures may have an effect on bond strengths of adhesive materials to root canal dentin. The purpose of this in vitro study was to evaluate the effect of various medications on microtensile bond strength to root canal dentin. Fourteen extracted human single-rooted teeth were used. The crowns and the pulp tissues were removed. The root canals were then instrumented and widened to the same size. The teeth were randomly divided into seven groups of two teeth each. The root canal dentin walls of the roots were treated with 5% sodium hypochloride (NaOCI), 3% hydrogen peroxide (H2O2), the combination of H2O2 and NaOCl, or 0.2% chlorhexidine gluconate for 60 s; or calcium hydroxide or formocresol for 24 h. The teeth in control group were irrigated with water. The root canals were obturated using C&B Metabond. After 24 h of storage in distilled water, serial 1-mm-thick cross-sections were cut, and approximately 12 samples were obtained from each group. Microtensile bond strengths to root canal dentin were then measured by using an Instron machine. The data were recorded and expressed as MPa. The results indicated that NaOCI, H2O2, or a combination of NaOCl and H2O2 treatment decreased bond strength to root canal dentin significantly (p < 0.05). The teeth treated with chlorhexidine solution showed the highest bond strength values (p < 0.05). In conclusion, chlorhexidine is an appropriate irrigant solution for root canal treatment before adhesive post core applications.     

Leakage resistance of the InnoEndo fiber obturation system.

To ensure long-term function, endodontic restorations require proper sealing of the root canal system. Recent studies have recognized that microleakage in endodontically treated teeth has negative consequences (ie, apical migration of bacteria) on their prognosis, often resulting in failure. Findings in the dental literature suggest that the innovative technology, consisting of fiber-based obturation and adhesive obturation materials, can minimize this leakage. As demonstrated in this article, the ability to achieve an adequate marginal seal represents a significant advance in endodontic therapy.     

5种根管封闭材料应用于根骨内种植体的根尖封闭性研究

采用亚甲基蓝染色法对５种常用的根管封闭材料用于根骨内种植体的根尖封闭性进行了体外实验研究。结果表明：氧化锌丁香油水门汀、磷酸锌水门汀和法国产的Ｓｅｐｔｏｄｅｎｔ根充剂具有较好的根尖封闭效果，其亚甲基蓝染色渗入长度分别为：１．８５，２．４４，１．８３（ｍｍ），显著好于传统的Ｏｘｐａｒａ糊剂和上海生产的根管充填剂。     

Influence of irrigants on the coronal microleakage of laterally condensed gutta-percha root fillings

AIM: To assess in vitro coronal microleakage in extracted human teeth after root-canal treatment, using different endodontic irrigants. METHODOLOGY: Fifty teeth with single root canals were prepared and filled using the lateral condensation of gutta-percha and Endométhasone sealer. Canal preparation consisted of initial shaping of the coronal two-thirds with Gates-Glidden burs size 2 and 3, followed by preparation of the apical stop and step-back flaring with manual files. Each group (n = 10) was irrigated with the following solutions: I--1% NaOCl, II--1% NaOCl + 17% EDTA, III--2% chlorhexidine gel, IV--2% chlorhexidine gel + 1% NaOCl, and V--distilled water. After root-canal filling, the teeth were incubated at 37 degrees C for 10 days followed by 10 days immersion in human saliva and an additional 10 days in India ink. The teeth were cleared and maximum dye penetration was determined digitally in millimetres. Statistical analysis was carried out using the Kruskal-Wallis test. RESULTS: Least leakage occurred with 1% NaOCl + 17% EDTA (2.62 mm) and 2% chlorhexidine gel (2.78 mm) (P > 0.05). NaOCl (3.51 mm), distilled water (6.10 mm) and 2% chlorhexidine gel + 1% NaOCl (9.36 mm) gave increased leakage with a significant difference compared to NaOCl + 17% EDTA and 2% chlorhexidine gel, and compared to one another (P < 0.05). CONCLUSIONS: Under the condition of this study, irrigation method during root-canal treatment influenced coronal microleakage. NaOCl + EDTA and chlorhexidine gel allowed better sealing following root filling.     

Apical sealing ability of five endodontic sealers

Because apical leakage may be a cause of failure of endodontic treatment, the purpose of this study was to compare the apical seal provided by five endodontic sealers. After cleaning and shaping procedures, the root canals of 75 human cuspids were obturated by lateral condensation using gutta-percha and the following sealers: Kerr Pulp Canal Sealer EWT, Grossman's sealer, ThermaSeal, Sealer 26, and AH Plus. These root-filled teeth were then maintained at 37 degrees C and 100% humidity for two days. After immersion in a solution containing black India ink and fetal bovine serum for five days, the teeth were demineralised and rendered transparent. The extent of dye penetration was examined under a stereomicroscope. The results showed that Grossman's sealer exhibited significantly more leakage than the other sealers, except ThermaSeal. There was no significant difference between ThermaSeal and AH Plus. No significant differences were observed for Kerr Pulp Canal Sealer EWT when compared with either ThermaSeal or AH Plus. There was significantly less leakage for Sealer 26 when compared with the other sealers tested, except AH Plus.     

Apical leakage of obturated canals prepared by Er:YAG laser

The present study evaluates the degree of apical leakage in vitro after root canal preparation using Er:YAG laser irradiation followed by obturation. Twenty-four single-rooted teeth were divided into 2 groups of 12. One group served as a control and these root canals were conventionally prepared up to a #50K file. The other group was prepared by Er:YAG laser irradiation at parameters of 2 Hz and 170 to 230 mJ/pulse. After obturation the teeth were immersed in a vacuum flask containing 0.6% rhodamine for 48 h, longitudinally bisected, and observed by stereoscopy and scanning electron microscopy. The degree of apical leakage from an apical stop was measured and statistical analysis was performed. The degree of apical leakage from the teeth prepared by laser was not significantly less than that from control teeth (p > 0.01). Morphological findings showed that contact between the root canal walls and obturated materials was hermetic in both groups, but canal walls prepared by laser were rough and irregular. These results show that root canal preparation by laser does not affect apical leakage after obturation compared with leakage in canals prepared using the conventional method.     

Microbial leakage of Cavit, IRM, and Temp Bond in post-prepared root canals using two methods of gutta-percha removal: an in vitro study

The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturated with gutta percha and AH26 sealer cement using the lateral cold condensation technique to a standardized working length of 15 mm. About 10 mm of the coronal gutta-percha was removed with either Peeso-reamer or a hot plugger. The roots were divided into three experimental groups of 10 roots and a control group. Each experimental group was subdivided equally into two groups of 15 each according to the method of post space preparation. Cavit, IRM, and Temp-Bond were used to seal the access opening. Each root was fixed in a cuvette containing Tryptic Soya Broth which, covered 2 mm of the root apex. Bacterial suspension was introduced through pipette. Fresh bacterial suspension was added every week, and the system was monitored daily for the growth of microorganisms for a period of one month. The results showed there was no significant difference in terms of coronal leakage between the three coronal materials used (P=0.478), but the methods of gutta-percha removal did have an impact on the apical leakage (P=0.047). The mean value showed the Peeso-reamer provided less leakage compared to using a hot plugger during the 30-day experimental time period. It was concluded the temporary type of coronal seal of endodontically treated teeth will not prevent coronal leakage if left for a long period of time. In addition, permanent cementation of the post with the coronal restoration should be carried out as soon as possible to prevent recontamination of the root canal.     

A comparison of four root canal filling techniques

This study compared the apical seal produced by four obturation techniques. Sixty-four extracted human teeth were prepared and obturated using lateral condensation of gutta-percha that was either unmodified or was dipped in chloroform, eucalyptol, or eucapercha paste. After storage in normal saline and 0.02% azide solution at 37 degrees C for 200 days, the teeth were immersed in India ink for 48 h. The most coronal extent of leakage of India ink into the canal was then determined. Significantly more apical leakage occurred in the eucapercha group than in the other three groups. All other comparisons were equivalent. The results suggest that modification of the gutta-percha master cone with solvent does not improve the apical seal in vitro. If modification is desired, then dipping the master cone in either eucalyptol or chloroform produces an apical seal superior to that achieved with eucapercha.