The essential endodontic literature: a survey of postgraduate program directors

Hundreds of new articles are added to the body of knowledge in endodontics each year. However, a comparatively small number of articles have had a disproportionately large influence on the progress and development of the specialty of endodontics. A survey of postgraduate program directors was conducted to attempt to identify a highly selective short list of articles that program directors felt should be included on every postgraduate reading list. The survey results were then compared with the more objective benchmark of citation indexing. The results of this survey suggest that the collective opinion of the postgraduate program directors correlates well with the results obtained from citation analysis.     

Development and evaluation of a self-instructional program in endodontic diagnosis and treatment planning.

This study was undertaken to evaluate two methods of instruction, the traditional lecture and the slide-tape method, both used with learning material developed for a course in endodontic diagnosis and treatment planning. Student performance, the amount of time required to complete the work, and the attitude of the students toward the differing methods of instruction were studied. The student sample, consisting of 108 members of the freshman class at the University of Southern California, was divided into two groups; the lecture group received a traditional two-hour lecture, and the slide-tape group had access to two slide-tapes on the same material. Both groups received a pretest and a posttest, and the students evaluated the teaching material. Statistical analysis showed no significant differences in quality of performance, but the lecture group spent more time learning the material, and students in the slide-tape group of instruction had a more favorable opinion of both the instructor (the voice) and the course material.     

A radiographic recall evaluation of 894 endodontic cases treated in a dental school setting

A radiographic recall evaluation of 894 endodontic cases treated by dental students at the University of Oklahoma College of Dentistry was conducted by faculty. The purpose of this study was to determine the success of standardized nonsurgical endodontic treatments by using radiographic techniques of determination and to compare the results to similar studies at other dental schools. Cases were labeled as successful, acceptable, questionable, and failing. Observations included time since treatment, age, gender, and tooth type. The combined percentage of successful and acceptable cases was 91.05%. Differences in percentage of success among recall time intervals were statistically significant (p < 0.01), as were the percentages of success between tooth types treated (p < 0.05). Success rate was not affected by age or gender (p > 0.05). The overall rate of successful and acceptable cases in this study was found to compare favorably with those from recall studies conducted at other dental schools.     

An evaluation of tricalcium phosphate as a treatment for endodontic perforations

In the rat, perforations of maxillary molars were created and treated with either tricalcium phosphate (Synthograft) or Cavit. At four time intervals (1 day, 1 wk, 2 wk, and 1 month), four evaluative factors (inflammation, bone resorption, cementum and dentin resorption, and epithelial proliferation) were analyzed and compared for the two materials. For the individual time periods, there were no statistically significant differences between the two materials. However, when all four time periods were combined, there was a statistically significant better result for tricalcium phosphate than for Cavit with respect to decreased inflammation (p less than 0.05).     

Prevalence and management of instrument fracture in the postgraduate endodontic program at the Dental School of Athens: a five-year retrospective clinical study

The aim of the present clinical research was to investigate the prevalence and management of instrument fracture during root canal preparation by postgraduate students (Department of Endodontics, Dental School of Athens) and to determine the percentage of referred cases with fractured instruments managed by the same students of the program. A retrospective study was conducted by reviewing the dental notes of 1367 patients (2180 endodontic cases, 4897 root canals) treated between October 2001 and June 2006 by endodontic postgraduate students at the Dental School of Athens. Type of tooth and canal, type and length of fractured segments, level of instrument fracture, and management that followed were recorded. The overall prevalence of instrument fracture during root canal preparation by postgraduate students was 1.83%. The prevalence of endodontic cases with fractured instruments referred to the endodontic postgraduates was 7.41%. The prevalence of stainless steel hand and rotary nickel-titanium instrument fracture by postgraduate students were 0.55% and 1.33%, respectively. The prevalence of instruments fractured in the apical third (52.5%) was significantly higher when compared with coronal (12.5%) and middle (27.5%) thirds of the canals. The retrieval or bypass of fractured instruments was most successful in the coronal (100%) and middle (45.4%) thirds when compared with the apical third (37.5%) of the canals. The fracture frequency was higher in retreatment cases in relation to the respective rate of initial therapies. On the basis of the results of this study, the prevalence of endodontic instrument fracture by the postgraduate students was relatively low. The prevalence of fracture of nickel-titanium rotary instruments was more frequent than that of hand instruments. Retrieval or bypass of the fractured instruments in the apical third was less successful.     

The organization and running of postgraduate endodontic ''hands-on'' courses

Considerable preparation, planning and detailed organization are necessary if endodontic 'hands-on' courses are to be stimulating and worthwhile for participant and teacher alike. Projection facilities, lighting, seating and working surface requirements must be checked immediately on arrival at the venue. The format, although flexible enough to allow for the wide range of knowledge and practical ability found within any one group, must adhere to and stress the current fundamentals in endodontic teaching. Not only can information and skill in diagnosis, root canal preparation and obturation be taught in a 'hands-on' format, but rubber dam isolation techniques can also be practised very successfully. Tutors must be prepared to demonstrate personally their clinical ability and experience of principles and techniques taught during the course. Post-course feedback can be an extremely useful means of ensuring that 'hands-on' courses are relevant, with the appropriate practical emphasis required by the general dental practitioner, as well as the necessary stress on endodontic principles.     

An evaluation of the Thermafil endodontic obturation technique.

The purpose of this study was to evaluate the Thermafil endodontic obturation technique and to compare it with laterally condensed gutta-percha. Thirty-seven maxillary central incisors were similarly prepared and divided into groups. Seventeen were obturated with Thermafil and 17 with lateral condensation. Three served as controls. After vacuum staining, all teeth were cleared and apical dye penetration was evaluated by two independent observers. Average leakage values were 0.24 mm and 1.32 mm for Thermafil and 0.47 mm and 1.18 mm for lateral condensation. There was no significant difference between the techniques, although a difference between evaluators was noted. Final results point to the relative subjectivity of in vitro leakage studies. When comparing the obturation times of both techniques, the Thermafil technique averaged 2 min 56 s while lateral condensation took 3 min 26 s. Statistical analysis showed no significant difference in obturation times.     

An evaluation of the CO2 laser for endodontic disinfection

The goal of this study was to evaluate the bactericidal action of the CO2 laser on animal teeth infected with an endodontic bacterial species. After instrumentation, 24 freshly extracted incisors were inoculated with a known concentration of Actinomyces odontolyticus and incubated anaerobically for 18 h. The incisors were separated into three groups: group 1--untreated control teeth; group 2--teeth treated with 3% NaOCl; and group 3--teeth lased with a CO2 laser at 5 W using three successive 9.9 s irradiation periods with 10 s between treatments. For each of the three groups, 60 microliters samples were removed using gel loading capillary pipette tips, and the diluted samples were plated in triplicate on Columbia agar plates. After a 5- to 6-day incubation, the colony-forming units were counted, and the quantitative results were subjected to an analysis of variance. The results of this analysis indicated an average 85% decrease in the colony-forming units in the laser-treated group, compared with the control group. According to Fisher and Scheffé tests, the differences in the averages between the control and laser groups were statistically significant (p < 0.05). The NaOCl treatment was statistically superior to the CO2 laser treatment.     

An in vitro method for longitudinal evaluation of toxicity of endodontic sealers

An in vitro method for longitudinal evaluation of root canal sealers was developed and applied. A newly introduced cell culture chamber was used to evaluate the cytotoxic effects of test samples immediately after mixing and for an extended period of time thereafter. A ranking of the test materials, based on their cytotoxicity, was allowed by the method.     

The potential etiologic factors influencing tinnitus intensity in patients with temporomandibular disorders

Objectives: To investigate the potential relationships between the intensity of tinnitus associated with temporomandibular disorders (TMD) and potential etiologic factors, including age, gender, freeway space, sleep bruxism (SB), joint clicking, and headache.

Methods: The sample was comprised of 90 patients without any hearing loss, as confirmed by otorhinolaryngology, who self-reported subjective tinnitus and simultaneous TMD, based on the Research Diagnostic Criteria for TMD (RDC/TMD).

Results: The results showed a positive, weak correlation between the intensity of tinnitus and age (r = 0.225, p = 0.033). The presence of SB and headache were seen in higher proportions in the present sample, at 75.5% (n = 68) and 66.6% (n = 60), respectively.

Conclusions: In a population of patients with subjective tinnitus and TMD, no significant associations were found between tinnitus intensity and age, freeway space, SB, clicking presence, and headache, though gender did show a weak correlation with tinnitus intensity.     

根尖倒充填术与根尖刮治术的临床疗效观察

目的 运用根尖倒充填术治疗常规根管治疗无法治愈的病例,并与根尖刮治术对比,观察临床疗效并评价其临床应用价值.方法选取通过常规根管治疗术无法处理或疗效不佳的根尖周炎患牙62颗,将其分为刮治组和倒充填组两组,每组31颗,在显微镜下分别进行根尖刮治术和根尖倒充填术,根据术后X线片判断即刻倒充填效果,术后1年、2年复查,根据患者感受、临床检查和X线片结果进行疗效评价.结果共有49颗患牙进行了疗效观察.刮治组1年及2年成功率分别为52%(12/23)、45%(9/20);倒充填组1年及2年成功率分别为85%(22/26)、88%(22/25).倒充填组1年和2年成功率均高于刮治组(1年成功率比较x2=6.0,P<0. 05;2年成功率比较x2=9.6,P<0.005).结论对根管治疗术无法处理或疗效不佳的患牙采用根尖倒充填术可获得良好的疗效.     

Radiographic quality of root canal fillings performed in a postgraduate program in endodontics

The aim of this study was to evaluate the standard quality of 1,347 root fillings performed by postgraduate students in Endodontics according to 3 radiographic quality parameters. The analyzed quality parameters included apical extension (AE), taper (TA) and homogeneity (HO), which received scores S2 (ideal standard), S1 (slight deviation) or S0 (accentuated deviation). A perfect filling (PF) received S2 for all parameters. In the absence of one or two S2 score, the fillings were deemed as satisfactory (SF) or deficient (DF), respectively. The results showed 51.7%, 41.5% and 6.8% of PF, SF, and DF, respectively. AE, TA, and HO presented equivalent quality parameters in root-filled canals of mandibular incisors and mandibular premolars (p>0.05). Conversely, in maxillary incisors, canines and distal root of mandibular molars, significant differences (p<0.05) were found between 2 parameters. Besides, there were significant differences (p<0.05) among the measured parameters in root-filled canals of maxillary premolars, all root canals of the maxillary molars and mesial root of the mandibular molars. AE showed the lowest frequency of S2 score for all groups. In conclusion the prevalence of perfect, satisfactory and deficient fillings varied significantly according to the root canal group. The quality parameters categorized fillings in 3 complexity degrees. AE was the most critical parameter of quality in root canal fillings.