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.

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.

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.

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.

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.

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.

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 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

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.

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.

Pulp management for caries in adults: maintaining pulp vitality.

BACKGROUND: There is a range of treatment options for the management of the pulp in extensively decayed teeth. These include direct and indirect pulp capping, pulpotomy or pulpectomy. If the tooth is symptomatic or if there are periapical bone changes, then endodontic treatment is required. However, if the tooth is asymptomatic but the caries is extensive, there is no consensus as to the best method of management. In addition, there has been a recent move towards using alternative materials and methods such as the direct or indirect placement of bonding agents and mineral trioxide aggregate. Most studies have investigated the management of asymptomatic carious teeth with or without an exposed dental pulp using various capping materials (e.g. calcium hydroxide, Ledermix, Triodent, Biorex, etc.). However, there is no long term data regarding the outcome of management of asymptomatic, carious teeth according to different regimens. OBJECTIVES: This study aims to assess the effectiveness of techniques used to treat asymptomatic carious teeth and maintain pulp vitality. SEARCH STRATEGY: Electronic searches of the following databases were undertaken: The Cochrane Oral Health Group's Trials Register (March 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 1), MEDLINE (1966 to week 4, February 2006), EMBASE (1974 to 13 March 2006), National Research Register (March 2006), Science Citation Index - SCISEARCH (1981 to March 2006). Detailed search strategies were developed for each database. Handsearching and screening of reference lists were undertaken. There was no restriction with regard to language of publication. SELECTION CRITERIA: Studies included were randomised controlled trials (RCTs). Asymptomatic vital permanent teeth with extensive caries were included. Studies were those which compared techniques to maintain pulp vitality. Outcome measures included clinical success and adverse events. DATA COLLECTION AND ANALYSIS: Data were independently extracted by three review authors. Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Oral Health Group's statistical guidelines were followed. MAIN RESULTS: Only four RCTs were identified. Interventions examined included: Ledermix, glycerrhetinic acid/antibiotic mix, zinc oxide eugenol, calcium hydroxide, Cavitec, Life, Dycal, potassium nitrate, dimethyl isosorbide, and polycarboxylate cement. Only one study showed a statistically significant finding; potassium nitrate/dimethyl isosorbide/polycarboxylate cement resulted in fewer clinical symptoms than potassium nitrate/polycarboxylate cement or polycarboxylate cement alone when used as a capping material for carious pulps. AUTHORS' CONCLUSIONS: It was disappointing that there were so few studies which could be considered as being suitable for inclusion in this review. The findings from this review do not suggest that there should be any significant change from accepted conventional practice procedures when the pulp of the carious tooth is considered. Further well designed RCTs are needed to investigate the potential of contemporary materials which may be suitable when used in the management of carious teeth. It is recognised that it is difficult to establish the 'ideal' clinical study when ethical approval for new materials must be sought and strict attention to case selection, study protocol and interpretation of data is considered. It is also not easy to recruit sufficient numbers of patients meeting the necessary criteria.

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.

Dental ceramics--an update.

The application of certain industrial ceramics and processing techniques has facilitated the introduction of a wide range of new dental restorative products including castable glass-ceramics, shrink-free materials and an ion-strengthening paste. However, these recent advances must be evaluated against the well-established materials and techniques developed more than 20 years ago. This article outlines interesting developments in the evolution of dental ceramics over the past 30 years and considers the current state of the art.

Ceramics update.

OBJECTIVE: The aim of this paper is to review recent developments in dental ceramics related both to the refinement of existing materials and technologies and to the development of new techniques. DATA SOURCES: The appropriate literature has been reviewed and the relevant information selected for inclusion in this article. CONCLUSION: It is concluded that the main advances are related to developments aimed to overcoming the mechanical shortcomings of ceramic materials, such as their inherent brittleness. Several new systems have been developed, some of which appear to be very promising, but there are, as yet, no data related to the long term performance of restorations by these new techniques.

A 3-year clinical evaluation of a porcelain inlay system.

OBJECTIVES: The porcelain inlay technique was described over a century ago, and, although not yet used as a routine restorative procedure, may prove to provide restorations of unsurpassed functional and aesthetic qualities in certain situations. The aim of this study was to investigate the handling properties and clinical characteristics of a porcelain inlay system, to highlight any advantages and disadvantages of the restorations under investigation, and to indicate further studies as considered appropriate. METHODS: Fifty moderate to large-sized Class 1 and Class II restorations of a porcelain inlay system were investigated in premolar and permanent molar teeth of 27 adult patients over a 3-year period using modified United States Public Health codes and criteria. Selected restorations were evaluated indirectly by scanning electron microscopic analysis. RESULTS: There was a high early rate of bulk fracture. By 6 months post-placement there had been a limited deterioration in marginal integrity associated with 20% of the remaining restorations, but this trend was not seen to continue. Patient acceptance was very favourable. CONCLUSIONS: It was concluded that the system under investigation afforded a technique-sensitive method of producing tooth-coloured restorations. Proposals for further work include investigations of the fitting accuracy of indirect tooth-coloured restorations, cavity design modifications and the use of alternative bases and luting agents.

Dentin-bonded all-ceramic crowns: current status.

Dentin-bonded all-ceramic crowns employ contemporary techniques to lute the crown to the tooth using a resin luting material and dentin-bonding system. The advantages of these crowns are that they provide good esthetics and fracture resistance and can be used in cases of substantial tooth loss. Their principal disadvantages are that the luting procedure is more time-consuming and that these crowns should not be used where margins are subgingival. Dentin-bonded all-ceramic crowns may be a useful addition to the dentist's armamentarium, but long-term clinical studies are needed to fully assess their performance.

Influence of different transitional restorations on the fracture resistance of premolar teeth.

Controversy exists over the most favorable material and type of restoration to be used to transitionally restore teeth destined to be crowned. This in vitro study uses fracture resistance testing to compare eight different transitional restorations in maxillary premolars. Ninety sound maxillary premolars were randomly selected and allocated to nine groups, each comprising 10 teeth. One group remained unrestored and was used as the control. Teeth in the remaining groups were prepared to a standard cavity form using: a copy milling process removing the palatal cusp. Restorations were placed using amalgam with dentin pins and cavity varnish; amalgam with an amalgam bonding agent; resin composite with dentin pins and a dentin bonding agent; resin composite with a dentin bonding agent only; resin-modified glass ionomer with dentin pins; resin-modified glass ionomer cement alone and cermet with dentin pins and cermet alone. Each restored tooth was then subjected to axial loading via a bar contacting the buccal and restored palatal cusps until failure of the restored tooth occurred. The mean load-to-fracture values were statistically compared and the modes of failure recorded. It was found that the choice of restorative material and type of restoration had little effect on the fracture resistance of the restored tooth with the exception of those teeth restored with reinforced glass ionomer cement alone, which exhibited a significantly lower resistance to fracture than the other restored teeth. However, the choice of restorative material/technique did influence the mode of failure. Failure in teeth restored with resin-modified glass ionomer cement alone produced the least damage to the remaining tooth tissue when failure occurred. Consequently, this material may offer the most favorable range of properties for the transitional restoration of extensively broken-down maxillary premolar teeth destined to be crowned. Furthermore, the findings of this study fail to support the use of dentin pins in the placement of bonded build-up restorations.

Student operator-assistant pairs: an update.

OBJECTIVE: To seek the opinions of undergraduates using the operator-assistant pairs system. DESIGN: A five-year evaluation of third-, fourth- and fifth-year students using a short, anonymous questionnaire OUTCOME MEASURES: This study set out to evaluate, but does not attempt to formally assess, the system. RESULT: Most students enjoyed working in pairs, citing mutual support and collaborative learning as being the main advantages. However, 67% of responding third- year students, 79% of fourth-year students and 54% of fifth-year students indicated that they did not know why paired working had been introduced. CONCLUSIONS: The majority of students found the pairs system advantageous over teacher-led situations. It encouraged greater efficiency, mutual support and help and collaborative learning.