Influence of the length of instrumentation and canal obturation on the success of endodontic therapy. A 10-year clinical follow-up

PURPOSE: To clinically test the periapical healing of the method of recurrent electronic root canal measurement and the method of root canal obturation by the guttapercha-eucapercha method. METHODS: During 10 years of endodontic practice of the first author, endodontic interventions were performed on approximately 4500 patients, aged 12-75 years. The success of therapy was followed-up in 257 teeth with diagnosis K04.0 to K04.5 (according to the X international classification of diseases) for whom a preoperative and control radiograph during the investigation period existed. Root canal preparation started with the "crown-down pressureless technique" and proceeded with the method of recurrent electronic root canal measurement. Obturation was done by the guttapercha-eucapercha method up to the apical constriction. RESULTS: The result of therapy success was approximately 95% overall (t-test, ANOVA); for the diagnosis: necrosis and pulp gangrene (K04.1): 64%; for the acute apical periodontitis (K04.4): 88%; for the inflamed pulp (K04.0) and pulp degeneration (K04.2) 95%; chronic apical periodontitis (K04.5): 98%, and abnormally formed hard tissue in the pulp (K04.3):100%.     

根管预备并发症及充填质量的临床评价

目的：对根管预备并发症及充填质量进行临床评价。方法：从Digora图像系统中抽取我科2002—04—05所完成的根管治疗病例805例，分别对前牙、前磨牙和磨牙根管预备并发症的发生和充填质量进行分析。结果：形成台阶和侧穿的比例在前磨牙分别为4％，而在磨牙中则分别为33％和5％。前牙、前磨牙和磨牙适充的比例分别为74％、69％和50％。结论：磨牙根管预备和充填的质量仍有待进一步提高。     

Basic techniques of root canal instrumentation

Many of the techniques for root canal instrumentation in endodontic treatment have been subject of great sophistication, relegating a second place the basic endodontic techniques which in our opinion can solve most of the cases that are treated by the general dental practitioner. We described each of this techniques the steps that have to be followed and the pros and cons. Finally a comparison of them is made, emphasizing the most relevant characteristics.     

Bacteriologic evaluation of the efficacy of mechanical root canal instrumentation in endodontic therapy

The presence of bacteria in 17 single-rooted teeth, with periapical lesions, was studied throughout a whole period of treatment. The root canals were irrigated with physiologic saline solution during instrumentation. No antibacterial solutions or dressings were used. Bacteria were found in all initial specimens from the teeth (median number of bacterial cells 4 x 10(5), range 10(2) - 10(7)) and the number of strains in the specimens ranged from 1 to 10.88% of the strains were anaerobic. The most commonly isolated species were: Peptostreptococcus micros, Peptostreptococcus anaerobius, Fusobacterium nucleatum, Bacteroides oralis, Bacteroides melaninogenicus subsp intermedius and Eubacterium alactolyticum. Mechanical instrumentation reduced the number of bacteria considerably. Specimens taken at the beginning of each appointment usually contained 10(4) - 10(6) bacterial cells and at the end 10(2) - 10(3) fewer. Bacteria were eliminated from the root canals of eight teeth during the treatment. In seven root canals bacteria persisted despite treatment on five successive occasions. There was no evidence that specific microorganisms were implicated in these persistent infections. Teeth where the infection persisted despite being treated five times were those with a high number of bacteria in the initial sample.     

Assessment of apical and coronal root canal seals using contemporary endodontic obturation and restorative materials and techniques

AIM: The purpose of this study was to evaluate the sealing ability of two contemporary endodontic obturation and restorative techniques and materials. METHODOLOGY: Seventy-nine extracted human single-rooted teeth were distributed randomly in two experimental groups of 36 and 37 specimens (groups 1 and 2, respectively), one group of three positive controls and one of three negative controls. The teeth were radiographed preoperatively, accessed, and instrumented. After smear layer removal, the teeth in group 1 were obturated using the System B and Obtura and were restored coronally with Core Paste using Tenure as a bonding agent. The teeth in group 2 were obturated using the Microseal technique and were restored coronally with amalgam using Panavia 21 as a bonding agent. All teeth in groups 1 and 2 were coated with three layers of nail varnish on all of their surfaces apart from the apical 4.0 mm and the coronal area above the cemento-enamel junction. The positive control teeth were obturated, restored coronally and completely coated with varnish, whereas the negative control teeth were not obturated, restored coronally, nor coated with varnish. The teeth were radiographed postoperatively and retained in saline solution for 10 days. For the next 10 days they were submerged in India ink. Subsequently all teeth were demineralized, dehydrated and rendered transparent. Dye penetration was measured using a stereomicroscope. RESULTS: All materials and techniques provided minimal to zero dye penetration, apart from one specimen in the Core Paste group that showed 4.0 mm of dye penetration. The Wilcoxon rank sum test and t-test showed no statistically significant differences and all materials and techniques tested presented with a high degree of acceptability. CONCLUSIONS: It was concluded that these contemporary techniques and materials provide equally good results, but long-term studies are needed for outright inferences to be drawn relative to their clinical performance.     

Bacteriologic evaluation of the efficacy of mechanical root canal instrumentation in endodontic therapy

Abstract – The presence of bacteria in 15 single-rooted teeth, with periapical lesions, was studied throughout a whole period of treatment. The root canals were irrigated with physiologic saline solution during instrumentation. No antibacterial solutions or dressigs were used. Bacteria were found in all irnitial specimens form the teeth (median numver of bacterial cell 4x10⁵; range 10²-10⁷) and the number of strains in the specimens ranged from 1 to 10.88% of the strains were anaerobic. The most commonly isolated species were: Peptostreptococcus micros, Peptostrcptococcus anacrobius, Fusobacterium nucleatum, Bacteroides oralis, Bacteroides melaninogenicus subsp. intermedius and Eubacterium alactolyticum. Mechanical instrumentation reduced the number of bacteria considerably. Specimens taken at the beginning of each appointment usually contained 10⁴-10⁶ bacterial cells and at the end 10²-10³fewer. Bacteria were eliminated from the root canals of eight teeth during the treatment. In seven root canals bacteria presisted despite treatment on five successive occasions. There was no evidence that specific microorganisms were implicated in these persistent infections. Teeth where the infection persisted despite being treated five times were those with a hig number of bacteria in the initial sample.     

根管充填质量对根管治疗术远期疗效的影响

目的：从X线影像角度分析根管充填质量对根管治疗远期疗效的影响。方法：选择已行根管治疗2a或2a以上的牙,运用平行投照法对根管治疗牙进行摄片;询问、查阅病史,了解患者年龄、性别、牙病病因及治疗时间;检查目前该牙根尖周状况;用SPSS13．0软件进行χ^2检验。结果：共调查病例215例,根管治疗牙376颗．成功率为54．79％。若以根管计算,共有513个根管,成功率为61．4％。根管充填质量（根充位置和密合度）对根管治疗疗效有显著的影响（P〈0．01）,根充距离X线片根尖0．5．2mm时最理想;根充密合者成功率高,尤其是根尖部。性别、年龄和根管充填时间对根管治疗疗效无影响。结论：根管充填质量对根管治疗远期疗效有显著影响。     

根管治疗术中的疼痛原因分析及疼痛控制

根管治疗是牙髓病及根尖周病的一种有效治疗方法,已在临床上广泛使用,然而在治疗过程中及治疗完成后患者可能会出现各种原因的疼痛。本文对根管治疗术中疼痛发生的原因进行分析,从而为临床医生采取相应的有效措施和治疗手段缓解患者痛苦提供参考。     

Evaluation of temperature rise on the outer surface of teeth during root canal obturation techniques

The heat generated at the apical 2 mm of the outer root surface of extracted human canine teeth during three obturation procedures was measured. The rise in temperature was found to be less when a sealer was used in all obturation techniques. Temperatures as high as 44.02 degrees C were recorded with warm gutta-percha with no sealer, and the lowest temperature rise occurred with a thermoplasticized gutta-percha technique with a sealer. The thickness of the remaining dentin and cementum after cleaning and shaping were found to have no effect in reducing temperature rise. The results of this investigation indicated that temperature rise on the outer surface of the root as a result of heat-generating obturation procedures is negligible and will not have an effect on the supporting attachment apparatus.     

The use of gutta-percha for obturation during root canal therapy in latex-allergic patients

This article discusses using gutta-percha to obturate the root canal system of a latex-allergic patient and the possibility for an adverse reaction from the components in commercially produced gutta-percha. Precautions, treatment suggestions, and possible alternatives for endodontic treatment of latex-allergic patients are discussed.     

Apical limit of root canal instrumentation and obturation, part 1. Literature review

One of the major controversies in root canal therapy concerns the apical limit of instrumentation and obturation. The results of longitudinal prognostic studies, basic anatomical knowledge of the apical third of the root canal, and the histological pulp reaction to caries progression demonstrated the presence of a vital apical pulp remnant, even in the presence of a periapical lesion. Finally necrosis and bacteria establish themselves in the periapical lesion. All valid prognosis studies confirm the practice of staying short of the apex with a homogeneous obturation to obtain the highest success rate of 90-94% (when done by or under supervision of specialists; results in the general population had a failure rate greater than 50%). The location of the apical foramen(ina) related to root canal treatment most frequently ends short of the apex, often by several millimetres.     

Root surface temperature rises in vitro during root canal obturation using hybrid and microseal techniques

The aim of this in vitro study was to measure the temperature rise on the outer surface of roots during filling with hybrid technique and Microseal. Twenty extracted human maxillary and mandibular premolars with a single canal were randomly divided into two groups of 10 teeth each. In the first group, the teeth were filled with hybrid technique (thermomechanical compaction with Engine Plugger used following lateral condensation of the apical part of the canal), the second group was filled using Microseal. After root canal obturation the filling material was removed and the obturation procedure was repeated. A total of 20 obturations in each group were performed. Temperature changes were measured using a thermal imaging camera. The temperature of certain regions of the mesial surface was analyzed and the highest temperature values were recorded. Statistical analysis was performed using the Mann-Whitney U test. The mean increase of temperature during the hybrid technique with Engine Plugger was 23.8 degrees C, while during Microseal it was significantly lower (p = 0.000001) at 5.5 degrees C. The temperature rise generated by Microseal was below the critical level and should not damage supporting structures, however, the hybrid technique generated a relatively high temperature rise that may cause periodontal tissue damage.     

Efficacy of retreatment techniques for a resin-based root canal obturation material

Resilon/Epiphany obturation system is emerging as an alternative to gutta-percha (GP). The efficacy of retreatment techniques for Resilon removal has not been determined. The purpose of this study was to evaluate two commonly used retreatment techniques in the removal of Resilon. Sixty single-canal teeth were instrumented and obturated with either Resilon/Epiphany or GP/AH Plus. Each canal was randomly allocated to receive one of the two retreatment techniques-ProFile 0.06 rotary files combined with heat or chloroform. The time required to remove the obturation material was recorded and the cleanliness of canal walls was determined by stereomicroscope and electron microscopy. The results demonstrated that chloroform combined with rotary files was more efficient in material removal compared to heat (p < 0.05). Resilon was faster to remove than GP. Both techniques resulted in cleaner canal walls in the apical third of the teeth obturated with Resilon when compared to GP (p < 0.05).     

Rationale for the use of low-torque endodontic motors in root canal instrumentation

Abstract – Fracture of nickel‐titanium rotary files is an iatrogenic error which can seriously jeopardize root canal therapy. If a high‐torque motor is used, the instrument‐specific limit‐torque (fracture limit) is often exceeded, thus increasing the risk of intracanal failure. A possible solution to this problem is to use a low‐torque endodontic motor which operates below these values. If the torque is set just below the limit of elasticity for each instrument, the risk of fracture is likely to be markedly reduced. The purpose of this paper was to discuss mechanical properties of NiTi rotary instruments, the rationale for selecting low torque values, and to use clinically a new endodontic motor (step‐motor) which operates below the limit of elasticity of each rotary file. The step‐motor was found to be helpful in reducing the risk of instrument fracture. Irreversible material damage (plastic deformation) and instrument fracture were rarely seen. Low‐torque instrumentation also increased tactile sense and, consequently, mental awareness of rotary instrumentation.