The Endodontic Complexity Assessment Tool (E-CAT): A digital form for assessing root canal treatment case difficulty.

AIMS: To develop an evidence-based, valid and reliable assessment tool that educational establishments and dental practitioners may use to assess the complexity of root canal treatment (RCT) utilizing digital advancements. The study also aimed to provide a more objective definition of the term 'uncomplicated' root canal treatment as described by the Association for Dental Education in Europe (ADEE) and the European Society of Endodontology (ESE) undergraduate curriculum guidelines for Endodontology. METHODOLOGY: The development process involved a narrative review of the literature to identify the complexity factors associated with root canal treatment on permanent teeth; an iterative development and analysis process to assess the weighting of these factors; and the programming of digital software to enhance the efficiency and user interface of the assessment form. Validation of the tool was sought with a panel of 35 specialist endodontists to assess clinical scenarios and assess the consensus inter-examiner agreement with the outcomes provided by the E-CAT. The inter-user and intra-user reliability studies were conducted with 15 dentists to evaluate the same clinical cases and by repeating the experiment 9 months later. The ease of use of the form was also assessed. RESULTS: The E-CAT was successfully developed with a total of 19 complexity criteria and hosted on a secure server under the domain of www.e-cat.uk. The tool provides a smart interactive filtering mechanism and automatic background calculation of the risk scores. Three levels of complexity were defined: class I (uncomplicated), class II (moderately complicated) and class III (highly complicated). The consensus of the panel of endodontists had excellent agreement with the outcome of the E-CAT. The inter-user and intra-user reliability was found to be 0.80 and 0.90, respectively. The average time to assess a case was 1:36 min. CONCLUSION: The E-CAT gave promising results providing an efficient and reliable platform to assess the complexity of cases undergoing root canal treatments. The study design allowed the formulation of a more objective definition to describe 'uncomplicated' root canal treatment as referred to by the ESE and ADEE guidelines. This study is advantageous for educational, public health and referral pathways.

Colour match between porcelain and porcelain-repairing resin composites.

The aim of this study was to evaluate the differences in colour between dental porcelain and porcelain-repairing resin composites. Porcelain discs were fabricated using four dentine shades in 1mm and 2mm thicknesses. Another series of discs was fabricated in 1mm and 2 mm thicknesses using three different brands of composite. Four single shades were used for the 1mm thick discs, and four single and 12 combined shades for the 2mm thick discs. The colour was measured using a spectrophotometer and colour differences deltaE* were calculated between samples. Colour differences were in the range of (deltaE* = 3.5-26.9), above the accepted threshold for perceptibility (deltaE* > 1) with a number above the threshold for what is considered to be clinically acceptable (deltaE* > 5.5). Improvements in colour match were seen for certain shade combinations of repairing composites, in contrast to when a single shade of composite was used.

Performance assessment of Vita Easy Shade spectrophotometer on colour measurement of aesthetic dental materials.

Four different shades were used to produce 20 samples of resin-based composite and 20 samples of porcelain to evaluate the performance ability of an intra oral test spectrophotometer compared to a reference spectrophotometer. The absolute colour coordinates CIELAB values measured with both spectrophotometers were significantly different (p < 0.001). However, a high correlation was found (p < 0.001) despite the low concordance noticed. The colour difference deltaE* values calculated between different shades also were significantly different between both spectrophotometers (p < 0.05). Therefore, the Easy Shade can be used in dental practice and dental research with some limitations.

The evaluation of a novel method comparing quantitative light-induced fluorescence (QLF) with spectrophotometry to assess staining and bleaching of teeth.

This study reports the development and evaluation of a novel method using quantitative light-induced fluorescence (QLF), which enables its use for quantifying and assessing whole tooth surface staining and tooth whitening. The method was compared with a spectrophotometer to assess reliability. Two experimental phases, intrinsic stain formation and tooth whitening, were conducted in vitro on 16 extracted bovine teeth. Intrinsic stains were developed via access through lingual surfaces and root canals of these teeth using tea solution (2 g/100 ml, Marks and Spencer Extra Strong Tea, Marks and Spencer, London, UK) for 6 days. Stains were removed using 33% hydrogen peroxide (VWR Prolab, Leicestershire, UK) in cycles over 150 min. Stain development/whitening was monitored with QLF (Inspektor Research systems, Amsterdam, Netherlands) and spectrophotometry (Easy shade, Vita Zahnfabrik, Bad Säckingen, Germany). Parameters Delta F for QLF and Delta E for the spectrophotometer were obtained. The progression of stain intensity and removal observed by the methods were tested for correlation using Pearson's correlation coefficient. Intra-examiner reliability for each method was tested. QLF showed a high correlation with spectrophotometry for detecting and monitoring intrinsic tooth stain progression (Pearson coefficient r was -0.987 with correlation significant p < 0.0001). For stain removal, the Pearson coefficient (r) between both methods was -0.906 with no significance p = 0.094. The use of an external reference material in combination with the inner patch QLF analysis technique had the ability to detect and measure whole tooth surface staining and its removal longitudinally. The reliability of the method shows a potential clinical application.

An investigation into most effective method of treating stained teeth: an in vitro study.

OBJECTIVE: To assess the most efficacious method of treating stained teeth: bleaching alone, veneering alone or a combination of bleaching and veneering and whether the choice alters depending on the degree of staining. METHODS: Extracted teeth were sectioned to give 117 samples. These samples were split into unstained, lightly and darkly stained groups based on CIE-Lab value L*. The lightly and darkly stained groups were stained using tea. Teeth from each group were then assigned to one of four subgroups (control (C), bleaching alone (B), veneering alone (V), or a combination of bleaching and veneering (BV), each containing 13 samples. Veneering was performed using 0.8-mm thick ceramic veneer of shade B1. CIE-Lab values were recorded using a spectrophotometer and the colour difference (Delta E) was calculated for each intervention. The final colour was compared to the value for obtained from a B1 (Vita) Shade tab. Statistical significance was assessed using analysis of variance. RESULTS: In all three test groups, intervention resulted in a statistically significant colour change compared to the C group (p

The effect of bleaching, varying the shade or thickness of composite veneers on final colour: an in vitro study.

OBJECTIVE: To investigate whether bleaching prior to placement of a composite veneer had an effect on the final shade of the restoration and whether this was affected by the thickness or shade of the veneer. METHODS: Twenty bovine teeth were collected, sectioned and divided into two groups. One group was the non-bleached control, while the other was the bleached group. A colour reading was recorded using a spectrophotometer. The bleached group then underwent external bleaching with 38% hydrogen peroxide and a colour reading was recorded. Each of these two groups were further sub-divided into four subgroups, on which composite veneers were placed. These subgroups were: 0.5 m thick A1, 1 m thick A1, 0.5 mm thick A4 and 1 mm thick A4 composite veneers. Colour readings were recorded after veneer placement. Statistical significance was assessed using analysis of variance. RESULTS: There was a difference between the colour produced for the same veneer properties, between the bleached and non-bleached groups. For a thin (0.5mm) A4 veneer bleaching produced a statistically significant difference in the amount of colour change (DeltaE) compared to veneering alone. For A1, non-bleached group there is a significant difference in the DeltaE produced by altering the thickness of the veneer. CONCLUSION: Within the limitations of this study, we can conclude that bleaching prior to placement of a thin A4 dark veneer produces a significant difference in colour change. If no bleaching is performed, altering the thickness of an A1 veneer produces a significant colour difference DeltaE. However, if bleaching is carried out there is no significant difference.

The use of objective digital matching to achieve an esthetic composite restoration.

OBJECTIVE: To investigate the ability to match composite restorations to teeth using digital imaging and CIE L*a*b* color differences. METHODS: Ten extracted human central incisors were used. Eleven discs of composite of differing shades were produced and mounted on white cardboard to create a customized shade guide (CSG). The CSG was photographed next to each of the ten teeth in a phantom head using a digital SLR camera. The images were analyzed, and color differences (deltaE) between the teeth and the shade discs were calculated using CIE L*a*b* values. Three cavities were then drilled into the labial surface of each tooth. Composite shades with the lowest three deltaE values were then used to restore the cavities. Ten observers evaluated the teeth under a standard D65 light source and recorded the best match. RESULTS: The majority of the observers selected the lowest deltaE in six out of the 10 teeth, and in a further two out of 10 teeth the second lowest deltaE was chosen. CONCLUSION: The lowest deltaE selected by objective color matching was agreed as the best match by observers. The high correlation between digital and visual color matching confirms the ability of digital camera and image analysis software to detect color differences.

The effect of enamel porcelain thickness on color and the ability of a shade guide to prescribe chroma.

OBJECTIVE: To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. METHODS: Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thicknesses of 0.6, 0.8 and 0.6mm, respectively. The color of each disk was measured using a spectrophotometer. Enamel porcelain was reduced in thickness to 0.3mm and porcelain disks were remeasured. RESULTS: Reducing the enamel thickness of porcelain disk specimens significantly increased L) (p<0.05), b*, metric chroma and hue angle (p<0.001). For the three shades studied (3M1, 3M2 and 3M3) L* values were not significantly different (p>0.05) and chroma increased for 3M1 with the lowest chroma to 3M3 with the highest chroma, which is in line with the shade guide specifications. Although statistically significant (p<0.001) changes in hue angle between the three shades were small (less than 3 degrees overall). The difference in chroma between the three shades 3M1, 3M2 and 3M3 was greatest for the thin enamel layer than the thick enamel layer. SIGNIFICANCE: A change in enamel thickness from 0.6 to 0.3mm resulted in a three-unit change in L* and metric chroma and a 4 degrees change in hue angle. A change in enamel porcelain thickness will have a greater effect on higher chromatic shades than those with lower chroma. The ability of the shade guide to prescribe chroma was demonstrated but this could be offset by an anomalous enamel thickness.

Comparison of quantitative light-induced fluorescence (QLF) and digital imaging applied for the detection and quantification of staining and stain removal on teeth.

OBJECTIVES: This study compares the use of QLF with digital imaging in the detection and quantification of the development and removal of stain on teeth. METHODS: Two experimental phases, tooth staining and tooth whitening, conducted in vitro on labial 12 mm(2) enamel windows made on ten extracted bovine teeth, developed stains in 6-min cycles (2 min in each solution) using artificial saliva, chlorhexidine and tea solutions and removed them using sodium perborate monohydrate in 2-min cycle monitored at the end of each cycle with QLF (Inspektor Research Systems, NL) and digital photography (Fuji, Japan). The stain values were quantified as DeltaQ derived from QLF and DeltaE from digital imaging. This was observed by the two methods correlated with Pearson correlation coefficient (r). Regression equations (R(2)) were also obtained. RESULTS: For both staining and stain removal there was a statistically significant (p<0.01) reverse correlation between DeltaQ values for QLF (r=-0.924, R(2)=85.4%) and DeltaE values for digital imaging (r=-0.994, R(2)=98.8%), respectively. CONCLUSION: QLF showed a high correlation with digital imaging as a technique for detecting and monitoring tooth stains and tooth whitening in vitro. The potential for QLF with further development as a tool for monitoring staining and whitening of teeth may be possible in vivo in addition to the diagnostic ability for caries detection.

The effect of colour defective vision on shade matching accuracy.

One hundred and forty one male dental students and staff were screened for colour-defective vision. Ten colour-defective and 20 non colour-defective subjects then carried out a shade matching exercise using nine selected shades and another matched, shade tab (to test for consistency) from Vita shade guides. All shade matching took place under standard lighting conditions. Each subject also completed a short questionnaire relevant to shade matching. There were no significant differences found between colour-defective and non colour-defective subjects in shade matching abilities. Although both subject groups were similar in their shade matching abilities, individuals with colour defective vision perceived it to be a slightly more difficult exercise.

The use of digital imaging for colour matching and communication in restorative dentistry.

OBJECTIVE: To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'. METHODS: Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3. A second shade guide was used to match the selected shades. A Nikon Coolpix 990 digital camera with Nikon SB21B ring flash was used to record the digital images of the shade tabs of the two shade guides and the images were processed using Adobe Photoshop software. A total of 27 samples (three replicates of each shade of the nine tabs selected) were matched with a digital shade guide prepared from the digital images of the second shade guide by 10 observers on a computer screen (computerised matching method). The 10 observers also matched the same shade tabs using the conventional matching method simulated in a phantom head. In addition, colour values were obtained from the digital images using Adobe Photoshop and quantified according to an internationally recognised scale as CIELAB colour values, L*,a*,b*. The relationship of the digitally derived CIELAB values to the CIELAB values obtained using a reflectance spectrophotometer was investigated. RESULTS: The cross tabulation statistical analysis showed a statistically significant difference (p<0.001) between the conventional method and the computer method with a 43% and 61.1% correct match respectively. There was also a statistically significant difference between observers in both methods (p<0.001 and p<0.04 for the conventional and computer methods respectively). A statistically significant high correlation of the CIELAB colour values were found between both colour measurement methods (p<0.001). CONCLUSION: The observers' shade matching performance was significantly better with the computer method compared with the conventional one. There was a large variation in the observers' matching ability. The digital camera can be used as a means of colour measurements in the dental clinic.

The whitening effect of chlorine dioxide--an in vitro study.

OBJECTIVES: The aim of this study was to investigate the whitening properties and rate of bleaching action of chlorine dioxide and compare them with those of hydrogen peroxide of similar concentration. METHODS: Sixty bovine central incisor crowns were ground and polished until flat surfaces were obtained. The crowns were subjected to extensive staining cycles of artificial saliva, chlorehexidine and tea before being randomly assigned to three groups: chlorine dioxide (ClO2), hydrogen peroxide (H2O2) and deionised water (H2O). The crowns in each group were subjected to seven 2 min exposure cycles in addition to an extra 30 min cycle. CIE LAB spectrophotometric measurements were taken at baseline, after each 2 min, and each extended 30 min bleaching cycle. RESULTS: L* for ClO2 specimens was significantly higher only after the first 2 min cycle (p<0.001) while for H2O2 specimens, L* significantly increased after the first two cycles (p<0.001) and continued to increase, at a slower rate, until the end of the treatment cycles. ΔE was significantly greater within H2O2 than within ClO2 specimens (p<0.001). CONCLUSION: Chlorine dioxide whitens teeth at a faster rate than hydrogen peroxide. Specimens treated with chlorine dioxide were significantly lighter than those treated with hydrogen peroxide at the end of the first 2 min application cycle, however, extended exposures did not enhance color.

Validation of an extracted tooth model of endodontic irrigation.

An extracted tooth model of endodontic irrigation, incorporating reproducible inoculation and irrigation procedures, was tested against Enterococcus faecalis using a variety of different irrigants in a Latin square methodology. ANOVA revealed no significant variations between the twelve teeth or experiments undertaken on different occasions; however, variation between irrigants was significant.

Working length determination in general dental practice: a randomised controlled trial.

OBJECTIVE: To evaluate the ability of apex locators as a tool in determining working length in comparison to traditional working length radiographs in general dental practice. DESIGN: Randomised controlled clinical trial. SETTING: General dental practices in the North West of England.Subjects Adults requiring root canal treatment of at least one tooth with minimal or moderate difficulty. INTERVENTION: Root canal treatment was carried out with the working length determined by apex locator in the treatment group (AL), and periapical radiograph in the control group (PA). OUTCOME MEASURE: The acceptability of the master cone gutta percha measured from a radiograph before obturation was used as the primary outcome. RESULTS: Twenty-one of 23 fillings in the AL group were judged as acceptable, compared to 17 of 23 fillings in the PA group. This difference was not statistically significant. CONCLUSION: In general dental practice, no significant difference was found in working length determined using apex locator combined with a master cone GP radiograph or using the conventional method. There is a need for larger trials to investigate these methods further.

An investigation into the effect of try-in pastes, uncured and cured resin cements on the overall color of ceramic veneer restorations: an in vitro study.

OBJECTIVES: The aim of this study was to assess how different shades of try-in pastes, uncured and cured resin cements influence the overall color of porcelain veneer restorations. METHODS: Porcelain veneers of shade Vita 1M1 VM7 and 1mm thick were applied to bovine teeth using three shades of resin cement and their try-in paste produced by three manufacturers. Analysis of variance was carried out on the color difference values (ΔE*) between the Aquagel and both the try-in paste and cured resins. An assessment of the clinical significance of ΔE* between the try-in paste and the cured resin and also between the uncured and cured resin was made. RESULTS: There were statistically significant differences in veneers' colors when using different shades of both Calibra and Nexus resin cements (p<0.05). Also, statistically significant differences were noticed when using different shades of both Rely-X and Nexus try-in pastes (p<0.05). Color differences produced between the try-in pastes and the corresponding shades of cured resin cements ranged from ΔE* 1.05 to 3.34. The color differences between uncured and cured resins of the same shade ranged from ΔE* 0.78 to 1.41. CONCLUSIONS: Different colored try-in pastes and resin cements produced color changes which are clinically useful in changing the color of veneer restorations and therefore aid color matching to adjacent dentition. Clinically significant differences were found between try-in pastes and the cured resin of the same shade, however, there were relatively small changes measured between uncured and cured resins. The color match achieved by the try-in paste has to be treated with caution and further assessment of the restoration made with the resin in place before curing is recommended.

The erosive potential of some alcopops using bovine enamel: an in vitro study.

OBJECTIVES: Alcoholic soft drinks have become increasingly popular and have high concentrations of citric acid and alcohol so might have the potential to cause dental erosion. This study aimed to investigate the erosive potential of alcopops on bovine enamel in vitro. METHODS: Six bovine upper incisors were prepared and sectioned to give six slabs per tooth, 4mm x 4mm each. Each slab was covered with nail varnish, leaving an exposed window (2mm x 2mm). Samples were immersed in 20ml of each of the test solutions for 20min, 1h, and 24h under gentle agitation (100rpm). Enamel surface loss was determined using Quantitative Laser Fluorescence (QLF), Non-contact Profilometry (NCP) and Transverse Microradiography (TMR). RESULTS: Enamel loss occurred with all test drinks and the positive control (p<0.05), and the depth of lesion correlated with pH and time. No significant difference was observed between 20min and 1h exposure, although both times had significantly (p<0.05) greater erosion when compared with baseline. Within each alcopops group significant erosion had occurred at 24h exposure compared with the baseline and previous times. CONCLUSION: All the tested alcopops resulted in significant enamel loss at 24h (p<0.001) with direct correlation between degree of enamel loss and both pH and increasing exposure time.

The frequency of repeat general anaesthesia for teeth extractions in children.

AIM: The purpose of this study was to determine the frequency of repeat extractions under general anaesthesia (GA) in children. METHODS: The dental hospital records of patients attending for outpatient GA extractions at Liverpool University Dental Hospital, Liverpool, UK, between January and March 2003 were examined retrospectively. A data collection form was used to record the relevant information. RESULTS: A total of 278 patients with a mean age of 6.5 years (SD = 2.2 years) were seen for GA extractions. Of those, 33 patients (11.9%) with a mean age of 4.9 years (SD = 2 years) at the time of their initial GA had had a previous or would undergo a subsequent episode of GA extraction. The mean interval between repeat GA was 2.3 years (SD = 1.6 years). Fifteen cases (45.5%) had the repeat GA within 2 years. Radiographs were available as part of the assessment process for 84 (34.3%) of the 245 patients who had had a single episode of GA. However, of the 33 patients who had had a repeat GA, only seven (21.2%) had radiographs available at the time of the initial GA. Regarding the number of teeth extracted, a significant difference (P < 0.01) was found between the number of teeth extracted in patients who had had a single GA (mean = 4.6, SD = 2.5), compared with those extracted at the initial GA for the repeat GA group (mean = 3.2, SD = 2). CONCLUSION: The frequency of repeat GA is relatively low, but there is a need for appropriate treatment planning incorporating the use of radiographs to reduce this even further.

Microleakage of glass-ionomer cement placed in association with non-setting calcium hydroxide.

The purpose of this investigation was to determine whether non-setting calcium hydroxide [Ca (OH)2] cement placed in the root canal system of premolar teeth would affect the subsequent microleakage of a glass-ionomer restoration (GIC). Following selection, 62 human premolar teeth extracted for orthodontic reasons were accessed and root canals prepared according to a standardized procedure. The specimens were then allocated randomly into two major groups each of 30 teeth. Two other teeth were used as a positive and a negative control. The control group was restored with glass-ionomer cement following drying of the canal and placement of a cotton wool pledget. The test group had all canals dressed with non-setting Ca(OH)2 and then was subdivided, one set (n = 22) being restored following conditioning of the access cavity margins, the other (n = 8) having the margins cleaned with a hand excavator. Samples were assessed for microleakage using a two-point scoring system (leakage or no leakage) in conjunction with a clearing technique using AgNO3. Using Fisher's exact test, a statistically significant difference was found between the control and test groups (P < 0.05) but there was no significant difference between the excavated and conditioned cavities (P=0.55). It is concluded that contamination of access cavity margins with Ca(OH)2 during medication of a root canal interferes with the bond of GIC, resulting in increased microleakage in vitro.