Magnification in undergraduate endodontic teaching in the UK and Ireland: a survey of teaching leads in Endodontology.

AIM: To investigate the use of magnification in undergraduate endodontic teaching in dental schools within the UK and Ireland and identify factors that may impact on levels of adoption. METHODOLOGY: An electronic questionnaire was distributed to teaching leads in undergraduate endodontics in all UK and Ireland dental schools. RESULTS: Completed questionnaires were received from 15 of 18 course leads. The study revealed magnification is not universally embedded within the undergraduate curricula, and the majority of schools had no expectation for students to use magnification, although it was encouraged. The study provided insight into teaching staff factors, student factors and institutional factors that impact upon the adoption of magnification in undergraduate endodontic teaching. Although course leads utilized magnification in their own practice, this did not translate into institutional expectation for students to use magnification. Barriers to adoption of such an institutional expectation included cost and lack of staff training. CONCLUSIONS: Magnification has become viewed as an essential part of endodontic practice. The dental operating microscope has the most significant impact on endodontic visualization; however, the use of dental loupes in nonsurgical endodontics could be considered the minimum standard. The pedagogical dilemma faced by dental educators training undergraduates to behave in a manner that they themselves would not, cannot be rationalized on the basis of cost and lack of staff training. It is proposed that although significant, these barriers are not insurmountable and the use of dental loupe should become an expectation in undergraduate training in the UK and Ireland.

Pulp sensibility and vitality tests for diagnosing pulpal health in permanent teeth: a critical review.

The aim of this review was to critically appraise the literature related to pulp vitality and sensibility testing in order to determine the diagnostic accuracy of pulp tests with reference to a gold standard or control group. Implications of the results for research and clinical practice are also explored. The MEDLINE (Ovid), MEDLINE (PubMed), Embase and Cochrane databases were searched for English-language clinical trials in humans in which in vivo studies were designed to evaluate or compare the accuracy of selected pulp sensibility and pulp vitality tests in determining the state of pulpal health in permanent teeth. Studies were included only if the results were compared to a control group or to a valid gold or reference standard. Eight studies were identified. Shortcomings in research design were found to influence the findings. The limited number of studies investigating pulp vitality tests was insufficient to answer the research question. It was concluded from this critical appraisal of the literature that laser Doppler flowmetry appeared to be the most accurate method for diagnosing the state of pulpal health and came closest to serving as a gold standard. Pulp vitality tests proved superior to pulp sensibility tests for early and accurate assessments of the pulpal health of traumatized teeth. When accurately used and interpreted, pulp sensibility tests provide valuable diagnostic information, particularly when an electric pulp test is used in combination with either CO2 snow or Endo-Ice.

Rethinking root canal treatment: understanding the difference between preventing and treating endodontic infection.

Root canal treatment is a frequently performed procedure aimed to address pulpal and peri-radicular disease. It comprises a number of clinical steps regardless of the initial diagnosis. The emphasis of each step varies according to whether there is a vital pulp (non-infected) or if the pulp system contains necrotic, infected tissue and there is peri-apical pathology. This article aims to discuss the differences in performing root canal treatments on teeth with vital and non-vital pulps. The reader should understand the differences between performing a root canal treatment in teeth with vital pulps and those with infected root canal spaces and peri-radicular pathology.

Undergraduate endodontic education: what are the challenges?

To deliver the knowledge and skills required to equip undergraduate students for practice is a significant responsibility; graduates must be familiar with the diagnosis and treatment of pulpal and periradicular diseases and the preservation and restoration of pulpally compromised teeth. A greater understanding of the microbiological processes involved in endodontics and developments in instruments and materials have transformed our approaches to root canal treatment. Information technology has revolutionised certain aspects of education and has had an effect on endodontic teaching. Dental graduates will be expected to treat an increasingly elderly population and will enter a climate in which remuneration for root canal treatment could have a significant effect on the number of cases treated and the pattern of referral. Teachers of endodontics at the majority of dental schools are taxed by competing demands for time in packed curricula, a lack of availability of natural teeth for classroom exercise and a lack of suitable patients. The debate as to whether endodontics should be a specialist subject in its own right has rumbled on for three decades. Compared with the situation in the 1970s, there are now well defined curricula guidelines to which those involved in teaching can refer and map teaching in their schools against agreed norms. These create the potential for students to graduate with the knowledge and skills at a sound level of competence to carry out endodontic procedures and with a deeply engrained understanding of the need for continuing professional development.

Resorption: part 1. Pathology, classification and aetiology.

This paper will explore the pathological process involved in dental resorption as well as its classifications and aetiology. The second subsequent paper will look at its diagnosis and management.

Resorption: part 2. Diagnosis and management.

In this second paper the clinical indicators of root resorption and their diagnosis and management are considered. While the clinical picture can be similar, pathological processes of resorption vary greatly from site to site and this paper proposes appropriate approaches to treatment for teeth that are affected by resorption.

Effect of retained fractured instruments on tooth resistance to vertical fracture with or without attempt at removal.

AIMS: To investigate the effect of retained fractured endodontic instruments on root strength and to evaluate the effectiveness of several root filling materials in reinforcing roots that had undergone unsuccessful attempt at removal of fractured instruments. METHODOLOGY: Seventy five mandibular premolar roots were divided into five groups. In group A (control), canals were prepared to a size F5-ProTaper instrument and filled with gutta-percha and TubliSeal sealer fragments. In the experimental groups (B, C, D and E), 4 mm of F5-ProTaper instruments were fractured in the apical one-third of the canal and then treated as follows: in group B, the fragments were left in situ without attempt at removal, and canals were filled with gutta-percha and TubliSeal sealer (GP No Removal). In groups C, D and E, an attempt at removal of the fragment was simulated by preparing a staging platform coronal to the fragment using modified Gates Glidden burs (No 2-5). Canals in group C were filled with gutta-percha and TubliSeal sealer (GP Removal), group D filled with Resilon (Resilon Removal) and group E with mineral trioxide aggregate (MTA Removal). Roots then underwent vertical fracture. Data were analysed using the one-way anova at P<0.05. RESULTS: Roots in the GP Removal group had significantly lower values for mean force for fracture (404.9 N). There was no significant difference between the control group and GP No Removal (765.2 and 707.8, respectively). Resilon Removal and MTA Removal groups (577.3 and 566.6 N) were not significantly different from the GP No Removal group. CONCLUSIONS: Leaving fractured instruments in the apical one-third of the canal does not appear to affect the resistance of the root to vertical fracture; Resilon and MTA appear to compensate for root dentine loss that occurred as a consequence of attempts at retrieval of fractured instruments when used as canal filling materials.

The impact of different viewing conditions on radiological file and working length measurement.

AIM: To determine the effect of different viewing conditions and observer experience upon the accuracy of file and working length measurements using analogue intra-oral radiographs. METHODOLOGY: Twenty-five observers from a range of clinical backgrounds examined working length analogue periapical radiographs of 30 extracted teeth. Each participant measured both file (FL) and working length (WL) on each of the radiographs using three different viewing conditions consisting of a viewing box, a viewing box with film masking and a viewing box with film masking and x2 magnification. Statistical analysis was conducted to derive interobserver reliability by intraclass correlation coefficients, and multiple linear regression models were fitted to compare the mean differences between the joint consensus between specialists and estimated values for file length and working length for each of the three viewing conditions. RESULTS: Multiple regressions models were fitted and found significant differences between the use of the viewing box alone and a viewing box with masking (FL P = 0.001; WL P < 0.001) and the use of the viewing box alone and with a viewing box employing masking and magnification (FL P < 0.001; WL P = 0.002). Intraclass correlation coefficient showed a high level of agreement between all observers; however, no statistically significant differences were found between the five observers groups for either mean file length or working length values. CONCLUSIONS: The results of this study are in agreement with National and European guidelines, which recommend the use of a viewing box, magnification and masking for radiographic interpretation.

Vertical fracture resistance of roots after ultrasonic removal of fractured instruments.

AIMS: To investigate ex vivo root resistance to vertical fracture after fractured instruments were ultrasonically removed from different locations in the root canal. MATERIALS AND METHODS: Fifty-three canine roots were weighed and divided into four groups. Eight roots served as a control group in which canals were instrumented to a size F5-ProTaper instrument. In the experimental groups, F5-ProTaper fragments were fractured in the coronal, middle and apical one-thirds, and then removed ultrasonically. The time required for removal was recorded. Roots were reweighed, and canals were shaped to a size F5-ProTaper and filled with GuttaFlow. After incubation, roots underwent a vertical fracture test in which the force at fracture was recorded. The difference in root mass before and after treatment (fractured file removal or canal preparation) was calculated. Data were analysed using the Kruskal-Wallis, Mann-Whitney post-hoc and regression tests at P < 0.05. RESULTS: The highest root-mass loss was recorded when fragments were removed from the apical one-third (46.04 mg) followed by the middle and coronal (27.7 and 13.5 mg, respectively); these differences were significant (P < 0.05). There were significant differences in the force required for vertical fracture amongst the experimental groups (P < 0.05) with the lowest mean force recorded in the apical-third group (107.1 N) followed by the middle and coronal (152.6 and 283.3 N, respectively). The highest mean force was recorded in the control group (301.5 N) which was not significantly different from that in the coronal group (P = 1.00). A negative exponential correlation (r = 0.669) existed between the root-mass loss and the force required to fracture the roots. CONCLUSION: Whilst removal of fractured instruments from the coronal one-third of the root canal can be considered as a safe procedure, removal from deeper locations renders the root less resistant to vertical fracture.

A laboratory evaluation of the physical and mechanical properties of selected root canal sealers.

AIM: To evaluate and compare the porosity, degree of conversion (DC) and hardness of two resin-based sealers; RealSeal and EndoRez, and a silicon-based sealer; GuttaFlow to that of a traditional zinc oxide-based sealer; TubliSeal. METHODOLOGY: For porosity, four samples from each sealer were prepared and scanned using a SkyScan 1072 Micro-CT. Porosity was then calculated using specialized software. For DC, 10 samples from each sealer were prepared and placed onto a Fourier transform infrared spectroscopy spectrometer. Spectra readings were carried out before and after curing of the sealers, and the DC for each sealer was calculated. For hardness, 10 samples from each sealer were prepared and then tested using a Wallace hardness tester. SPSS software was used for statistical analysis of the data using one-way anova and independent t-tests. RESULTS: TubliSeal had the highest percentage porosity (3.52%), whilst RealSeal had the lowest percentage porosity (0.41%). Statistically significant differences (P = 0.01) in porosity were present between all groups except between RealSeal and EndoRez groups. RealSeal exhibited a significantly higher DC% than EndoRez (P = 0.01), whereas EndoRez had the highest hardness number [28.54 Vickers hardness number (VHN)] whilst TubliSeal showed the lowest (13.57 VHN). Statistically significant differences in hardness were found between all groups (P = 0.01) except between RealSeal and EndoRez groups. CONCLUSIONS: Resin-based sealers had less porosity, greater hardness and a high DC.

Endodontists experience using ultrasonics for removal of intra-canal fractured instruments.

AIM: To investigate the experience of UK endodontists with aspects of ultrasonic use for removal of intra-canal fractured instruments. METHODOLOGY: A questionnaire form comprising both close-ended and partially close-ended questions with a covering letter explaining the aims of the study and indicating that all information would remain confidential and anonymous were sent to 180 endodontists working in the UK. Non respondents received a reminder with a differently worded covering letter. After collecting the responses, data were entered into SPSS software through which frequencies were determined and the chi-square test at the 0.05 level of significance, when required, was applied. RESULTS: Overall, 97% of endodontists reported the use of ultrasonics for removal of fractured instruments. The majority of them (78%) used ultrasonics with a coolant at least some of the time. Forty-seven per cent of users activated tips at medium to maximum power settings. The greatest proportion (53%) activated the tips for approximately 10 s. CONCLUSIONS: Endodontists reported different techniques when using ultrasonics for removal of fractured instruments.

The influence of coronal tooth tissue in the diagnosis of apical pathosis.

AIM: To assess the influence of the status of the crown of the tooth on the observers' periapical radiological assessment. METHODOLOGY: Seven clinical tutors, eight postgraduate students and seven undergraduate students were recruited. Each evaluated 24 periapical radiographs comprising 12 radiographs with teeth restored with small to medium coronal restorations and 12 radiographs displaying teeth which were either heavily restored or exhibited gross caries. Two viewing sessions, separated by several weeks, were undertaken using ideal viewing conditions. In the first viewing teeth were examined in their entirety and in the second the coronal aspects of the teeth were obscured. RESULTS: An analysis of variance found no significant differences between the groups of observers during the first viewing. When the crowns were masked, undergraduate students had a significantly lower sensitivity (P = 0.008) compared with postgraduates and clinical tutors. Paired t-tests found a significant increase in the sensitivity of the postgraduate students between the first and second viewing (P = 0.037). Mean sensitivity and specificity for the undergraduates decreased from 0.67 to 0.63 and 0.64 to 0.60 for the first and second viewing, respectively, whilst mean sensitivity for postgraduates and clinical tutors increased from 0.59 to 0.79 and 0.69 to 0.80, respectively. Specificity increased from 0.72 to 0.78 for the postgraduates between viewings, whilst the tutors recorded 0.80 for each viewing. CONCLUSION: The status of coronal tooth tissue had a major impact on the diagnostic accuracy of the observers with limited radiological experience supporting the need for earlier radiological training within the undergraduate curriculum.

Opinions and attitudes of endodontists and general dental practitioners in the UK towards the intracanal fracture of endodontic instruments: part 1.

AIM: To investigate the attitudes and opinions of general dental practitioners (GDPs) and endodontists in the UK towards fracture of endodontic instruments. It was hypothesized that there would be no significant difference between GDPs and endodontists regarding their experience of fracture of endodontic instruments. METHODOLOGY: A pilot questionnaire was carried out on 20 postgraduate dental students to ensure that the questions were easily understood. This was followed by a further pilot survey on a group of GDPs and endodontists (50) to facilitate sample size calculation. The sample size comprised 330 systematically selected GDPs, and all endodontic specialists working in the UK (170). The questionnaire comprised both close-ended and partially close-ended questions in four categories: demographics; pattern of practice and experience of instrument fracture; management of fractured instruments; and unsuccessful management of fractured instruments. Nonrespondents were sent another two mailings (first and second reminders). After collecting the responses, data were analysed using chi-square and Linear-by-Linear Association tests at the 0.05 level of significance. RESULTS: The overall response rate was 75% (82.82% for endodontists and 70.92% for GDPs). Overall, 88.8% of respondents had experienced fractured instruments with a significantly higher proportion of endodontists (94.8%) compared with that of GDPs (85.1%). CONCLUSION: Both endodontists and GDPs were aware of most factors contributing to endodontic instrument fracture. With experience and knowledge, fracture of endodontic instruments was associated with the number of root canal treatments performed.

Cleaning endodontic files in a washer disinfector.

AIMS: The aim of this study was to compare the cleanliness of endodontic files that had been cleaned in a washer disinfector according to the file holding mechanism within the machine. METHODOLOGY: Selected canals of extracted teeth were filed with new, unused files. One set of files (size 15 to 40) was used for each canal. A total of 192 files were used for cleaning and shaping. The files were divided into three groups. The first group was a control group containing 30 files, which were not cleaned in the washer disinfector. The second and the third groups were the experimental groups with 81 files in each group. These files were cleaned in the washer disinfector using different holding mechanisms (file holder or cleaning basket) for each group. The files were examined for visible debris under a light microscope at x45 magnification. RESULTS: None of the 162 cleaned files were totally free of organic debris. Comparison of the debris scores in the two experimental groups showed that the files in the cleaning basket group were significantly cleaner than those in the file holder group. The files in both test groups were significantly cleaner than those in the control group. CONCLUSIONS: Endodontic files cannot be totally cleaned using a washer disinfector alone. The instrument holding mechanism within the machine has a significant effect on the cleanliness of the files after one intensive cleaning cycle.

Factors contributing to the separation of endodontic files.

Cleaning and shaping of the root canal system is essential for successful endodontic treatment. However, despite improvements in file design and metal alloy, intracanal file separation is still a problematic incident and can occur without any visible signs or permanent deformation. Only a few studies have reported high success rates of fractured file removal using contemporary techniques. Conflicting results have been reported regarding the clinical significance of retaining separated files within root canals. An understanding of the mechanisms of, factors contributing to, file fracture is necessary to reduce the incidence of file separation within root canals. This article reviews the factors that are of utmost importance and in light of these, preventive procedures and measures are suggested.

The failure rate of NHS funded molar endodontic treatment delivered in general dental practice.

OBJECTIVE: To describe the quality and record the outcomes of root canal therapy on mandibular, first permanent molar teeth provided by GDPs working according to NHS contracts. DESIGN: Descriptive, retrospective cohort study. SETTING: Twelve general dental practices in Salford, North West England. SUBJECTS AND METHOD: All patients aged 20-60 years attending the practices who had received a NHS-funded root filling in a mandibular first permanent molar between January 1998 and December 2003. The radiographic quality of root fillings in the teeth was assessed by an endodontic specialist and categorised into optimal, suboptimal and teeth which had no radiograph, or an unreadable radiograph. Teeth were also dichotomised into those restored with a crown and those restored with an intracoronal restoration. Failure as an outcome was defined as if a tooth was extracted, the root filling was replaced or periradicular surgery was performed on the tooth. Crude failure rates per 100 years were calculated for optimally, sub-optimally root filled teeth and for those with no or an unreadable radiograph, and according to how the tooth was coronally restored. Survival was assessed using Kaplan-Meier curves and Cox proportional hazards were used to determine factors linked with increased failures. RESULTS: One hundred and seventy-four teeth were included in the study, of which 16 failed. The crude failure rates per 100 years with a root filled tooth were very low and differed little (p = 0.9699) for optimally (2.6), sub-optimally (2.5) root filled teeth and for those with no or an unreadable radiograph (2.9), with approximately one in 37 root filled mandibular first molar teeth failing each year. The majority of root fillings fail within the first two years (N = 10, 62.5%). Some 67 teeth (38.5%) were restored with a crown, none of which failed during the follow up period compared to those with a plastic restoration (p = 0.0004). CONCLUSIONS: The very low failure rates have significant implications for the design of research studies investigating outcomes of endodontic therapy. The similar failure rates for teeth that had optimal and suboptimal root fillings suggest that endodontic treatment is not as technique sensitive as previously thought. The results also support the notion that the coronal restoration is more important than radiographic appearance of the root filling.

Opinions and attitudes of endodontists and general dental practitioners in the UK towards the intra-canal fracture of endodontic instruments. Part 2.

AIM: To investigate the attitudes of general dental practitioners (GDPs) and endodontists in the UK towards management of fractured endodontic instruments. METHODOLOGY: A questionnaire was sent to 330 systemically selected GDPs and all endodontists working in the UK (170). It was accompanied by a covering letter explaining the aims of the study and indicating that all the information given would remain confidential. Those who did not respond to the first mailing were sent another two mailings. Data were analysed using chi-square test at P

Comparison of an ultrasonic cleaner and a washer disinfector in the cleaning of endodontic files.

The aim of this study was to compare the amount of residual organic debris on endodontic instruments that had been cleaned in either an ultrasonic bath or a washer disinfector prior to sterilisation. A total of 90 endodontic files of varying sizes were used to clean and shape root canals in extracted teeth and were then placed in endodontic file holders. Test group 1 (36 files) were ultrasonically cleaned for 10 min and test group 2 (36 files) were cleaned in a washer disinfector. A control group (18 files) were not cleaned at all. Following sterilisation, all the files were visually inspected under a light microscope and scored using an established scale. The results showed that both test groups had significantly less residual debris than the control group. Comparing the test groups, the files that had been cleaned ultrasonically had significantly less debris than those cleaned in the washer disinfector. The design of the instrument holder may have been a factor in this result. More research is needed into the use of washer disinfectors in the cleaning of small dental instruments that have a complex surface structure.

The use of outreach clinics for teaching undergraduate restorative dentistry.

AIM: To examine the experience of being an outreach teacher of undergraduate restorative dentistry; to describe the desirable characteristics of such teachers; and to consider the management of outreach teaching. DESIGN: A three year pilot of an outreach course in fourth year restorative dentistry began in 2001. Students spent one day per week treating adults in NHS community dental clinics, run by Primary Care Trusts (PCTs). Action research involved monitoring meetings with students, clinic staff (dental teachers and nurses), and PCT clinical service managers. These data are supplemented by an independent evaluation involving interviews with dental school academic staff, and an account by an outreach teacher. RESULTS: Outreach is a different and more demanding context for teaching restorative dentistry than the dental hospital, characterised by isolation, management responsibility, pressure, a steep learning curve, and stress. The desirable characteristics of outreach teachers are those which enable them to cope in this environment, together with a student-centred teaching style, and the appropriate knowledge. Management of teaching passed to the PCTs and this created an additional workload for them in relation to staffing, risk, and service-based issues. Four teaching surgeries were the maximum for a satisfactory level of patient care and student supervision. A key issue for the dental school is quality. The changes to teaching and the teaching environment introduced during and after the pilot to address problems identified are described. CONCLUSION: In developing facilities to enable students to benefit from the advantages of outreach, dental schools should recognise that the characteristics of the outreach environment need to be taken into account during planning, that staff selection is a critical success factor, and that an ongoing proactive approach to organisational arrangements and to the support of teaching staff is necessary.