In vitro bacterial penetration of coronally unsealed endodontically treated teeth

Forty-five root canals were cleaned, shaped, and then obturated with gutta-percha and root canal sealer, using a lateral condensation technique. The coronal portions of the root filling materials were placed in contact with Staphylococcus epidermidis and Proteus vulgaris. The number of days required for these bacteria to penetrate the entire root canals was determined. Over 50% of the root canals were completely contaminated after 19-day exposure to S. epidermidis. Fifty percent of the root canals were also totally contaminated when the coronal surfaces of their fillings were exposed to P. vulgaris for 42 days.     

In vitro bacterial penetration of endodontically treated teeth coronally sealed with a dentin bonding agent

This study evaluated the effectiveness of a dentin bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenol-based sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher's exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p = 0.002) and 90 days (p = 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p = 1).     

Survival analysis of endodontically treated traumatized primary teeth

The present study aimed to verify the factors that interfere with the success of endodontic treatment of traumatized primary teeth as well as to determine the success level of the proposed treatment, through survival analysis. The research was conducted through the analysis of dental traumatism records and attached radiological exams of patients assisted by the Assistance Program for the Traumatized Patient at UFSC (Universidade Federal de Santa Catarina). Fifty-one dental records of patients aged between 10 and 60 months were analyzed. These patients had their traumatized teeth endodontically treated (n = 51), according to the indications of the UFSC protocol. In order to evaluate possible interference factors affecting the success of the endodontic treatment, the following items were analyzed: age of the child at the beginning of the endodontic treatment (over or below 36 months), trauma type (mild or severe) pathological root resorption type (replacement or inflammatory), localization of the pathological root resorption (in the apical third or in the middle third), bone resorption (absent or present), alteration of the soft tissue (absent or present), condition of the pulp tissue (vitality or necrosis) and trauma recurrence (absent or present). Through the chi-squared test (chi(2) = 9.594, P < 0.05) and survival analysis, it was verified that trauma recurrence in the same tooth is a factor that interferes in the success of endodontic treatment. It was also observed, through survival analysis, that levels of success of endodontic treatments are stabilized in the 19th month. A period of 48 months of follow up was observed. It was also verified that most failures occurred between the 7th and 12th months counting from the beginning of the endodontic treatment. It was concluded that endodontic treatment of traumatized primary teeth, performed according to the UFSC protocol, enables the maintenance of the traumatized tooth in acceptable conditions in the buccal cavity up to its physiological resorption, and that trauma recurrence is a factor that leads to treatment failure.     

Influence of coronal restorations on the periapical health of endodontically treated teeth

Abstract – The purpose of the study was to evaluate a possible relationship between the quality of the coronal restoration, the root canal obturation and the periapical status of endodontically treated teeth. Full mouth series of radiographs from randomly selected patient charts at the Dental Faculty, University of Oslo were examined. A total of 1001 endodontically treated teeth restored with a permanent restoration were evaluated independently by two examiners. According to a predetermined set of radiographic criteria, the technical quality of the root filling of each tooth was scored as either good (GE) or poor (PE), and the technical quality of the coronal restoration was scored as good (GR) or poor (PR). The root and the surrounding structures were then evaluated and according to the periradicular findings, the treatment was categorized as success or failure. The success rate for all endodontically treated teeth was 67.4% ( n =1001). Teeth with root canal posts had a success rate of 70.7% ( n =527) and teeth without posts had a success rate of 63.6% ( n =472). The two groups with technically good endodontics had the highest success rates. In combination with technically good restorations the success rate was 81% (GE+GR, 81%) and combined with technically poor restorations the success rate was 71% (GE+PR, 71%). The two groups with technically poor endodontics combined with either good restorations or poor restorations had significantly lower success rates (PE+GR, 56% and PE+PR, 57%). The technical quality of the endodontic treatment as judged radiographically was significantly more important than the technical quality of the coronal restoration when the periapical status of endodontically treated teeth was evaluated.     

In vivo fractures of endodontically treated posterior teeth restored with amalgam

Abstract The cumulative survival rate (retention of both cusps) and the fracture pattern of 1639 endodontically treated posterior teeth were assessed in a retrospective study. All teeth had an MO/DO or an MOD cavity restored with amalgam without cuspal overlays. The 20-year survival rate of teeth with an MO/ DO cavity was markedly higher than that of teeth with an MOD cavity. The lowest survival rate was found for the upper premolars with an MOD cavity: 28% of these teeth fractured within 3 years after endodontic therapy, 57% were lost after 10 years, and 73% after 20 years. Generally, the cusp most prone to fracture was the lingual one, and lingual fractures caused significantly more damage to the periodontal tissues than did facial or total crown fractures. The severity of periodontal damage increased with posterior location of the tooth. By far the most serious failures, irrespective of the cavity type, were found for the upper second molar, as 10 of 29 fractures led to extraction. It is concluded that amalgam, especially in MOD cavities, is an unacceptable material for restoration of endodontically treated posterior teeth if used without cuspal overlays.     

根管治疗牙最终被拔除的原因分析

目的 :以最终被拔除的根管治疗牙为研究对象 ,来评判其失败的原因。方法 :收集分析 77例拔除的根管治疗牙资料 ,进行分类研究。结果 :与修复有关的失败占 6 1.0 % ,其中主要是冠折。与牙周疾病有关的失败占 2 9.9% ,根管治疗的失败仅占 9.1%。结论 :根管治疗自身的失败比较少见 ,但一旦发生 ,后果严重 ,平均寿命较短。冠修复的根管治疗牙比未冠修复的根管治疗牙平均寿命长。     

Endodontic decision-making under uncertainty: A decision analytic approach to management of periapical lesions in endodontically treated teeth

Abstract Management of periapical lesions in endodontically treated teeth is subject 10 considerable interexaminer variation. This uncertainty can be approached by using formal decision analysis. Temporal and logical display of decision alternatives, values of probabilities and utilities of various outcomes arc tin-features of such an analysis. The present study deals with two endodontic cases in which probability values were provided by two groups of examiners (general practitioners and endodontists) through the Delphi group opinion technique. Utility values were determined by the authors. For each decision alternative, a so-called expected value could be calculated by multiplying values of probability and utility. The expected values are proposed to act as guidelines for the selection of optimal decision strategy.     

Are posts mandatory for the restoration of endodontically treated teeth?

Abstract— In this era of fiscal and professional accountability, variations in the utilization of posts to improve the retention of crowns or other restorations on endodontically treated teeth are no longer acceptable. This practice ignores not only the potential for root perforations during post space preparations, but also the adhesive properties of modem resin-based materials. Since the retention of restorations hinges on many other factors, the placement of posts does not necessarily assure service quality and may even lead to deleterious changes. The need to reappraise the utilization of posts in the restoration of endodontically treated teeth cannot be overstated.     

Long-term prognosis of endodontically treated teeth: a retrospective analysis of preoperative factors in molars

Introduction

Long-term predictability of restored endodontically treated teeth is important for the decision of tooth retention versus extraction and implant placement. The purpose of this study was to validate the hypothesis that preoperative factors can predict the long-term prognosis of molars requiring endodontic and restorative treatment for future prognostic investigations.

Methods

A clinical database was searched for molar endodontic treatments with crown placement and a minimum of 4-year follow-up. Charts of 42 patients with 50 individual treatments were randomly selected. Information concerning crown lengthening; periodontal diagnosis; attachment loss; furcation involvement; mobility; and internal, external, or periradicular resorption was recorded. Radiographs from treatment initiation and follow-up were digitalized. The presence of apical periodontitis was evaluated. Available ferrule was calculated from bitewing radiographs using CAD software (AutoCAD; Autodesk, Cupertino, CA). The resulting data, age, sex, and times of restoration and follow-up were analyzed for correlation with the presence of apical radiolucency at follow-up and the following four possible outcome scenarios: “no event,” “nonsurgical retreatment,” “surgical retreatment,” or “extraction” using Spearman rank order correlation analysis.

Results

Patients’ ages ranged from 19 to 87 years, 22 were male and 20 female, and 48 teeth (96.0%) were retained at follow-up. Of those, 44 (88.0%) were without intervention (“no event”), and four (8.0%) underwent surgical or nonsurgical retreatment. Two teeth (4.0%) had been extracted. Significant positive correlations existed between “untoward events” (any form of retreatment or extraction) and “prognostic value according to periodontal status” (p = 0.047) and “attachment loss” (p = 0.042).

Conclusion

The only preoperative factors significant for the prognosis of restored endodontically treated molars were related to periodontal prognostic value and attachment loss. It can be concluded that it may be difficult to predict the prognosis of molars in need for endodontic treatment and restoration from prognostic factors not related to periodontal disease.     

In vitro comparison of intact endodontically treated teeth with and without endo-post reinforcement.

In an in vitro experiment, the failure loads of 59 intact endodontically treated teeth with and without Kerr Endo-Post reinforcement were compared. Fifty-eight teeth fractured below the cementoenamel junction. One tooth fractured through the pulp chamber with a chisel fracture involving both the crown and root. Teeth without posts fractured through the middle or coronal one third of the root. Teeth with posts fractured through the body of the post. No statistically significant reinforcement was demonstrated by cementing a Kerr Endo-Post No. 100 into a sound endodontically treated tooth.     

In vitro microbial leakage of endodontically treated teeth using new and standard obturation techniques

Coronal microbial leakage is an important cause of apical periodontitis and thus should be prevented if possible. The purpose of this study was to compare microbial leakage of new and standard obturation techniques over a 30-day period. A split chamber microbial leakage model was used in which Streptococcus mutans placed in the upper chamber could reach the lower chamber only through the obturated canal. Leakage was assessed every day for 30 days. One hundred forty single-rooted human teeth were used in this study, equally split between lateral, vertical, and Obtura II condensation; SimpliFill with Obtura II condensation; FibreFill; and a combination of FibreFill and SimpliFill. Cochran-Mantel-Haenszel row mean score statistics showed a high statistical significance when all groups were compared (p < 0.0001). Microbial leakage occurred more quickly in lateral and vertical condensation techniques compared with SimpliFill and FibreFill techniques. A combination of an apical plug of gutta-percha with SimpliFill and a FibreFill coronal seal was the best obturation technique used (SimpliFill-FibreFill group).     

Stress analysis of endodontically treated teeth restored with post-retained crowns: A finite element analysis study

BackgroundThe authors conducted a study to analyze the stress concentration areas in a tooth restored with a post-retained crown under various conditions.Materials and MethodsThe authors constructed a three-dimensional finite element model describing a maxillary second premolar restored with an all-ceramic crown supported by a titanium post and a resin-based composite core. They applied static vertical and horizontal loads of 100 newton to the cusp tip of the crown and recorded Von Mises and tensile stress values. The variables investigated were the presence of the post, coronal and apical post extensions, post diameter, post shape, and post and core material.ResultsThe study results showed that horizontal loading generated higher levels of stress than did vertical loading. The greatest stress levels were concentrated at the cervical region and at the post-dentin interface in all models. Under both loads, a higher modulus of elasticity of the post material and a wider post diameter were associated with increased stress values at the post-dentin interface. Reduction of the post extension above the level of bone was associated with increased dentinal stresses near the apex of the post.ConclusionsAlthough endodontic posts provide retention for coronal restorations, they result in dentinal stress values higher than those of crowns without posts. Posts that had a similar modulus of elasticity to dentin and smaller diameters were associated with better stress distribution. Resting coronal restorations on sound dental tissues affected stress distribution more than did the core material or the length of the coronal post extension.Clinical ImplicationsMany factors influence the distribution of stress within dentin and, consequently, the fracture resistance of teeth restored with post-retained crowns. Clinicians need to keep these factors in mind when performing endodontic procedures that involve placement of post-retained crowns to ensure optimal success.     

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根管治疗牙齿的修复并保存终生是一项具有挑战性的工作，有几个关键性因素影响根管治疗牙和修复体长期保存，本文的目的是阐述这些基本原则，另外还涉及桩核的设计、桩道的预备和黏结等相关内容。     

Restoration of endodontically treated teeth

Endodontically treated teeth have lost substantial tooth structure as a result of previous restorations, dental caries, and the access preparation for the endodontic therapy. The topic of restoring these teeth is complex and controversial, and their long-term prognosis is directly connected to the quality of the final restoration. This article describes contemporary knowledge of the biomechanical principles related to the restoration of pulpless teeth and provides a critical review of currently available materials and methods.     

根管内屏障对根管治疗牙冠方微渗漏影响的体外研究

完整单根管前磨牙42颗,截去牙冠,常规根管治疗,随机分为4组,2%亚甲基蓝染色,2周后取出,制作透明样本,体视显微镜观察并测量样本微渗漏长度,并对数据进行统计学分析。结果显示阴性对照组未见染料渗入根管,阳性对照组见整个根管被染色(单因素方差分析,P<0.001),微渗漏长度的均数和置信区间由GP(4.80±0.54,4.42～5.19)、ZPC(3.39±0.65,2.92～3.85)、Filtek Z350(2.07±0.27,1.87～2.27)至Fiju VⅡ(1.68±0.15和1.57～1.79)呈递减趋势,两两比较,除Filtek Z350与F ijuVII间差异无统计学意义外(P>0.05),其余各组间差异均有统计学意义(P<0.05)。说明根管内屏障能够提高根管治疗牙冠方封闭能力;Filtek Z350、Fuji VⅡ可作为根管内屏障材料应用于临床。     

暂时封固对根管治疗牙冠方微渗漏影响的体外研究

目的 评价不同暂封材料、暂封方式对根管治疗牙冠方微渗漏的影响,探讨根管治疗牙冠方微渗漏发生情况及与时间的关系.方法 收集离体牙,常规根管治疗后随机分组,2%亚甲基蓝染色,制作透明样本,体视显微镜下观察样本微渗漏情况,根据染料渗漏最大长度评分,收集数据并进行统计分析.结果 暂封1、4 周时,Cavit-G和Caviton微渗漏评分低于氧化锌丁香酚水门汀(ZOE);暂封2 周,Caviton微渗漏评分低于ZOE和Cavit-G.ZOE作为暂封材料,两种方式样本微渗漏评分比较差异无统计学意义(P > 0.05);暂封1 周时,Cavit-G和Caviton直接与间接暂封微渗漏评分差异无统计学意义(P > 0.05),暂封2周,Cavit-G和Caviton微渗漏评分差异无统计学意义(P > 0.05).随暂封时间的延长,3种材料的微渗漏差异有统计学意义(P < 0.05).结论 Caviton冠方暂封效果最好,其次为Cavit-G,ZOE最差;间接暂封明显加速Cavit-G和Caviton暂封样本冠方微渗漏;Caviton和 Cavit-G用于暂封的适宜时间为2周,ZOE为1周.     

根管治疗牙正畸加力后根吸收的相关因素研究

目的研究固定正畸治疗对根管治疗牙牙根吸收的影响和相关因素分析。方法选择正畸治疗前口腔内已完善根管治疗牙45例,利用治疗前后的全口曲面断层片,以改良根吸收分级法评估患者治疗前后牙根形态变化,分析正畸治疗对根管治疗后牙根吸收的影响。结果①正畸治疗后根管治疗牙牙根吸收有所增加,差异具有统计学意义（P〈0．001）;②性别是影响正畸治疗后根管治疗牙牙根吸收方程最为显著的因素（P〈0．05）,提示女性发生根吸收的风险大于男性;③正畸治疗后根管治疗牙与对侧活髓牙比较牙根吸收程度的改变差异没有统计学意义（P〉0．05）;④在所观察的样本中,无论根管治疗牙齿与活髓牙均未见3级根吸收。结论根管治疗牙在固定正畸治疗后可能发生一定程度的根吸收改变,但并不比活髓牙的风险更高。     

Bone level around endodontically treated teeth in periodontitis patients

Objectives: This retrospective study compared the marginal bone level of teeth with root canal fillings with contra‐lateral teeth without. Methods: Of 286 consecutive patients (35 years), referred to practice for periodontology in the Netherlands, 67 full sets of radiographs contained 1 endodontically treated tooth and its contra‐lateral tooth without root canal treatment. Bone level at the mesial and distal of these teeth was scored from the CEJ. In multi‐rooted teeth, the presence of interradicular radiolucency was assessed. The presence of posts, and periapical radiolucencies was assessed. Analysis for differences between treated teeth and contra‐laterals was controlled for tooth surface, presence of a post and tooth type. Results: The mean distance from the root filling to the apex was 2.6 mm. Periapical radiolucencies were found in 14%. The mean bone level was at 4.3 mm for endodontically treated teeth and at 3.7 mm for contra‐laterals. Significantly more bone loss (0.6 mm) was found at the endodontically treated teeth. No difference was found between mesial and distal, teeth without and with posts and different tooth types. The presence of interradicular radiolucency was more frequent in endodontically treated teeth (OR 2.1, p_{(McNemar test)}=0.039). Conclusion: In periodontitis patients, teeth with endodontic treatment had more bone loss as compared with untreated contralaterals.