Changes in the prognostic values of modern cardiovascular biomarkers in relation to duration of diabetes mellitus

BACKGROUND

Based on the complex pathophysiology of type 2 diabetes and atherosclerosis we hypothesized a dynamic change in prognostic value of cardiovascular biomarkers over time.

METHODS

In this prospective study 746 patients with type 2 diabetes mellitus, being followed up for 60 months were analysed. The primary endpoint was defined as unplanned hospitalization for cardiovascular disease or death. Beside others, especially the prognostic performance of the biomarkers of interest (GDF-15, NT-proBNP, hs-TnT) was evaluated in relation to quartiles of diabetes duration.

RESULTS

In patients having a diabetes duration below 7 years lnGDF-15 (HR 2.84; p < 0.01) and lnhs-TnT (HR 2.96; p < 0.01) were significant predictors of the primary endpoint. LnAge (HR 40.01; p < 0.01) and lnNT-proBNP (HR 1.56; p = 0.03) were significant predictors in patients with a diabetes duration between 7 and 12 years. In the third quartile (diabetes duration 12-22 years) lnurinary albumin to creatinine ratio (HR 1.25; p = 0.005) and lnNT-proBNP (HR 2.13, p < 0.001) predicted the endpoint. In patients with a diabetes duration above 22 years, lnAge (HR 75.35; p = 0.001) and lnNT-proBNP (HR 2.0; p < 0.01) were the only significant predictors of the endpoint.

CONCLUSION

Prognostic power of cardiovascular biomarkers changes dynamically in relation to duration of type 2 diabetes mellitus. In patients with shorter duration of the disease markers of subclinical cardiovascular dysfunction and inflammation perform better than markers of systemic advanced organ dysfunction and cardiovascular disease.

In vitro evaluation of root canal wall cleanliness in primary molars after preparation with Self-Adjusting-File (SAF) or Mtwo NiTi-instruments and final irrigation

AIM

In vitro evaluation of cleanliness of root canal walls of primary molars after preparation with the Self-Adjusting-File and Mtwo-instruments and final irrigation with citric acid and sodium hypochlorite.

MATERIALS AND METHODS

s Study Design: In 23 matched pairs, teeth were prepared either with SAF or with Mtwo NiTi-instruments, and final irrigation was performed with 2 mL citric acid and 4 mL NaOCl. Roots were split longitudinally, SEM-images were taken, and smear layer was evaluated by two blinded observers using a four-grade score. Statistical evaluation was performed with Mann-Whitney-U-Test and Wilcoxon Signed Rank Test (P<0.05).

RESULTS

No significant difference between SAF and Mtwo (P=0.9454) was observed. Overall removal of the smear layer was significantly better in the coronal part of the root canal than in the apical one (P=0.0004393). Mtwo showed no significant difference in cleanliness when comparing the coronal and apical part of the root canal (P=0.1089), whereas SAF cleaned the coronal part of the root canal significantly better than the apical part (P=0.00108).

CONCLUSION

None of the two instruments was superior concerning cleanliness in root canals of primary molars. Both show good cleaning ability when using an irrigation protocol with citric acid and sodium hypochlorite.

Effects of Levosimendan on cardiac function, size and strain in heart failure patients

Levosimendan improves cardiac function in heart failure populations; however, its exact mechanism is not well defined. We analysed the short-term impact of levosimendan in heart failure patients with ischemic and non-ischemic cardiomyopathy (CMP) using multiparametric cardiac magnetic resonance (CMR). We identified 33 patients with ischemic or non-ischemic CMP who received two consecutive CMR scans prior to and within one week after levosimendan administration. Changes in LV ejection fraction (LVEF) and LV volumes, as well as changes in strain rates, were measured prior to and within one week after levosimendan infusion. LV scarring, based on late gadolinium enhancement (LGE), was correlated to changes in LV size and strain rates. Both LV endiastolic (EDV) and endsystolic volumes (ESV) significantly decreased (EDV: p=0,001; ESV: p=0,002) after levosimendan administration, with no significant impact on LVEF (p=0.41), cardiac output (p=0.61), and strain rates. Subgroup analyses of ischemic or non-ischemic CMP showed no significant differences between the groups in terms of short-term LV reverse remodeling. The presence and extent of scarring in LGE did not correlate with changes in LV size and strain rates. CMR is able to monitor cardiac effects of levosimendan infusion. Short-term follow-up of a single levosimendan infusion using CMR shows a significant decrease in LV size, but no impact on LVEF or strain measurements. There was no difference between patients with ischemic or non-ischemic CMP. Quantification of LV scarring in CMR is not able to predict changes in LV size and strain rates in response to levosimendan.

Accessing distributions of exchange and dipolar couplings in stiff molecular rulers with Cu(ii) centres

Novel approaches to quantitatively analyse distributed exchange couplings are described and tested on experimental data sets for stiff synthetic molecules.

A critical appraisal of studies on cyclic fatigue resistance of engine-driven endodontic instruments

The endodontic literature contains a plethora of studies on static and dynamic cyclic fatigue resistance tests performed on a large array of rotary or reciprocating nickel-titanium endodontic instruments. It was the aim of this review to summarize the currently available evidence to point out the different outcomes from static versus dynamic tests and to assess whether cyclic fatigue tests provide useful data and information for clinical practice. An electronic literature research in the database PubMed was performed using appropriate search terms, and the titles and abstract were screened for relevance. Language was restricted to English. The review reveals marked differences between the results obtained in static and dynamic tests, and also, the results for the same instruments assessed either under static or dynamic experimental conditions are widely inconsistent. Between the lowest and the highest value for one and the same pathfinding instrument was a factor of about 123 when cyclic fatigue was assessed either under static or dynamic experimental conditions. Moreover, standard deviations of up to 30% have been reported. Environmental temperature has a 500% impact on the lifetime of instruments. In conclusion, fatigue resistance tests conducted under room temperature should be regarded as having little meaning and the scientific and clinical benefits of fatigue resistance tests are very limited. These data should be provided by the manufacturer of the instruments.

Beneficial effects of levosimendan on survival in patients undergoing extracorporeal membrane oxygenation after cardiovascular surgery

BACKGROUND

The impact of levosimendan treatment on clinical outcome in patients undergoing extracorporeal membrane oxygenation (ECMO) support after cardiovascular surgery is unknown. We hypothesized that the beneficial effects of levosimendan might improve survival when adequate end-organ perfusion is ensured by concomitant ECMO therapy. We therefore studied the impact of levosimendan treatment on survival and failure of ECMO weaning in patients after cardiovascular surgery.

METHODS

We enrolled a total of 240 patients undergoing veno-arterial ECMO therapy after cardiovascular surgery at a university-affiliated tertiary care centre into our observational single-centre registry.

RESULTS

During a median follow-up period of 37 months (interquartile range 19-67 months), 65% of patients died. Seventy-five per cent of patients received levosimendan treatment within the first 24 h after initiation of ECMO therapy. Cox regression analysis showed an association between levosimendan treatment and successful ECMO weaning [adjusted hazard ratio (HR) 0.41; 95% confience interval (CI) 0.22-0.80; P=0.008], 30 day mortality (adjusted HR 0.52; 95% CI 0.30-0.89; P=0.016), and long-term mortality (adjusted HR 0.64; 95% CI 0.42-0.98; P=0.04).

CONCLUSIONS

These data suggest an association between levosimendan treatment and improved short- and long-term survival in patients undergoing ECMO support after cardiovascular surgery.

Consistency of electronic measurements of endodontic working length when using multiple devices from the same manufacturer-an in vitro study

OBJECTIVES

To assess the consistency of electronic determination of endodontic working length obtained from four identical electronic root canal length measurement devices (ERCLMD) from five different types of ERCLMD each under various in vitro conditions.

MATERIALS AND METHODS

Eight extracted teeth, seven single-rooted teeth, and one molar were accessed. Root length was measured and instruments were inserted and fixed with the tip placed beyond and short of the apical constriction, in roots with an artificial perforation or an open apex. Devices tested were Root ZX (Morita, Kyoto, Japan), Dentaport ZX (Morita), Apex ID (SybronEndo, Glendora, USA), ProPex II (Dentsply Maillefer, Victoria, Australia), and Raypex 6 (VDW-Antaeos, Munich, Germany). Teeth were irrigated with different solutions (NaOCl, EDTA, CHX). ERCLMDs were connected and measurements were recorded. Consistency was classified by the scores 0-4. Comparisons were carried out using the Kruskal-Wallis test (α = 0.05). For multiple testing, the level of significance was adjusted and analysis was performed using the Mann-Whitney U test.

RESULTS

Among the five types of ERCLMD, Apex ID and Raypex 6 showed the highest consistency. There was no statistically significant difference between the settings and conditions. Raypex 6 showed the highest consistency for measurements in case of a perforation.

CONCLUSION

Different devices from one type of ERCLMD show a high consistency. Nevertheless, general statements on the accuracy of one type of ERCLMD taken from studies investigating only one device per type should be drawn with caution.

CLINICAL RELEVANCE

The study refers to the reliability and repeatability of determination of endodontic working length by using ERCLMDs.

Effect of final irrigation procedures on fracture resistance of root filled teeth: an ex vivo study

AIM

To evaluate the effect of chlorhexidine (CHX) on fracture resistance of roots treated with different concentrations of ethylenediaminetetraacetic acid (EDTA).

METHODOLOGY

One hundred and twenty intact single-rooted premolar teeth were sectioned below the cementum-enamel junction to standardize the length of the teeth to 12 mm. The canals of one hundred specimens were instrumented with ProTaper Universal rotary instruments up to size F4 and were randomly divided into five groups (n = 20) according to the final irrigating solutions: Group 1: distilled water (DW); Group 2: 5% EDTA and 2.5% NaOCl; Group 3: 17% EDTA and 2.5% NaOCl; Group 4: 5% EDTA, 2.5% NaOCl, DW and 2% CHX; Group 5: 17% EDTA and 2.5% NaOCl, DW and 2% CHX. Root canals were filled with gutta-percha and epoxy resin-based root canal sealer using a single-cone technique. Twenty teeth served as negative controls and were not instrumented nor root filled (Group 6). All specimens were embedded in self-curing acrylic resin and loaded vertically at 0.5 mm min^-1 until fracture occurred. The data were evaluated statistically using one-way anova test followed by Holm-Sidak's multiple comparison test (P < 0.05).

RESULTS

Group 1 (only DW) had the lowest vertical fracture strength, followed by Group 3 (17% EDTA and 2.5% NaOCl; P < 0.05). Group 6 (negative control group) had the highest fracture resistance. Final irrigation with CHX following irrigation with 17% EDTA or 5% EDTA and 2.5% NaOCl (groups 4 and 5) significantly increased the fracture resistance of roots (P < 0.05). However, the difference between Group 4 and Group 5 was not significant (P > 0.05).

CONCLUSIONS

Intracanal CHX rinse of EDTA/NaOCl-treated root dentine enhanced the fracture resistance of roots filled with AH Plus.

Association of nutritional risk index with metabolic biomarkers, appetite-regulatory hormones and inflammatory biomarkers and outcome in patients with chronic heart failure

AIMS

We aimed to evaluate the association of the nutritional status by using the nutritional risk index (NRI) with metabolic and inflammatory biomarkers, and appetite-regulatory hormones in a cohort of stable patients with heart failure (HF), and to analyse its prognostic value.

METHODS AND RESULTS

In this prospective observational cohort study, we included 137 stable chronic HF patients (median age, 60 years; median body mass index, 27 kg/m(2) ) with optimised medical treatment. Baseline NRI of < 113 (n = 45) was associated with a significant increase in the levels of ghrelin (p < 0.001), peptide YY (p = 0.007), pentraxin-3 (p = 0.001), tumour necrosis factor-alpha (p = 0.018), adiponectin (p < 0.0001) and the N-terminal prohormone of brain natriuretic peptide (NT-proBNP; p < 0.0001) compared with those in patients with NRI of ≥ 113. The NRI was found to be correlated with the homoeostasis model assessment of insulin resistance index (r = 0.444; p < 0.0001) and inversely correlated with the NT-proBNP level (r = -0.410; p < 0.0001). The overall mortality rate was 20%. A baseline NRI of < 113 was associated with a higher risk of all-cause mortality (log rank = 0.031).

CONCLUSION

We propose that the NRI is a useful and easily applicable tool for the early identification of nutritional depletion in patients with chronic HF as it discriminates metabolic changes prior to the clinical manifestation of body wasting. Furthermore, poor nutritional status, represented as a low NRI, is associated with an increased incidence of death in such cases.

The effect of four different irrigation systems in the removal of a root canal sealer

OBJECTIVES

The aim of this study was to compare the efficiency of sonic, ultrasonic, and hydrodynamic devices in the removal of a root canal sealer from the surface and from simulated irregularities of root canals.

MATERIALS AND METHODS

Fifty-three root canals with two standardized grooves in the apical and coronal parts of longitudinally split roots were covered with AH Plus root canal sealer. Compared were the effects of (control) syringe irrigation, (1) CanalBrush, (2) passive ultrasonic irrigation, (3) EndoActivator, and (4) RinsEndo on the removal of the sealer. The specimens were divided into four groups (N = 12) and one control group (N = 5) via randomization. The amount of remaining sealer in the root canal irregularities was evaluated under a microscope using a 4-grade scoring system, whereas the remaining sealer on the root canal surface was evaluated with a 7-grade scoring system.

RESULTS

Passive ultrasonic irrigation is more effective than the other tested irrigation systems or syringe irrigation in removing sealer from root canal walls (p < 0.01). None of the techniques had a significant effect on cleaning the lateral grooves.

CONCLUSIONS

Within the limitations of this study protocol ultrasonic irrigation shows a superior effect on sealer removal from the root canal surface during endodontic retreatment. Cleaning of lateral grooves seems not to be possible with one of the techniques investigated.

CLINICAL RELEVANCE

Incomplete removal of root canal sealer during re-treatment may cause treatment failure. Passive Ultrasonic irrigation seems to be the most effective system to remove sealer from a root canal.

Comparison of hand and rotary instrumentation for removing gutta-percha from previously treated curved root canals: a microcomputed tomography study

AIM

To compare the efficacy of hand and rotary nickel-titanium (NiTi) instruments in removing filling material from curved root canals of root filled teeth with unknown preparation parameters.

METHODOLOGY

Ninety mandibular molars with root fillings in curved root canals and homogenous root canal filling extending to 0-2 mm short of the radiographic apex were selected. Root canal curvatures and radii were measured in two directions and microcomputed tomography (micro-CT) scans were used to determine preoperative volumes of the filling material. Subsequently, the teeth were assigned to two identical groups (n = 14). The root fillings were removed with Hedström files or FlexMaster NiTi rotary instruments. Postoperative micro-CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were compared using analysis of covariance and analysis of variance procedures.

RESULTS

Root canals retreated with Hedström files were associated with less remaining filling material compared with FlexMaster instruments (P < 0.05). Both retreatment techniques removed similar amounts of dentine with no significant differences (P > 0.05). FlexMaster instruments were significantly faster than Hedström files (P < 0.05). No procedural errors were detected in the Hedström group, whilst three instruments fractured in the FlexMaster group.

CONCLUSIONS

Hand instrumentation resulted in significantly less residual filling material than retreatment with rotary NiTi instruments. Dentine removal was not significantly different for both techniques. FlexMaster NiTi rotary files were significantly faster than Hedström files, but were associated with a higher risk of instrument fracture.

Serum uric acid is related to cardiovascular events and correlates with N-terminal pro-B-type natriuretic peptide and albuminuria in patients with diabetes mellitus

BACKGROUND

Hyperuricemia is a risk factor for cardiovascular events and renal insufficiency. It correlates to intima-media thickness and microalbuminuria. In this study we evaluated uric acid as an independent marker for cardiac events in patients with diabetes.

METHODS

In a prospective observational study we recruited 494 patients with diabetes. Patients were then followed for 12.8 months (mean follow-up) and hospitalizations as a result of cardiac events (ischaemic heart disease, arrhythmias, heart failure) were recorded.

RESULTS

The median duration of diabetes was 11 ± 10.35 years. Patients were in the mean 60 ± 13 years old and mean HbA(1c) was 62 ± 13 mmol/mol (7.8 ± 3.3%). At baseline, mean uric acid was 321.2 ± 101.1 μmol/l (range 101.1-743.5 μmol/l), median N-terminal pro-B-type natriuretic peptide was 92 ± 412 pg/ml and median urinary albumin to creatinine ratio was 8 ± 361 mg/g; Uric acid significantly correlated to N-terminal pro-B-type natriuretic peptide (r = 0.237, P < 0.001) and urinary albumin:creatinine ratio (r = 0.198, P < 0.001). In a Cox regression model, including age, estimated glomerular filtration rate, gender, systolic blood pressure, smoking and alcohol consumption, uric acid was the best predictor of cardiac events (hazard ratio 1.331, confidence interval 1.095-1.616, P = 0.04). However, uric acid lost its prognostic value when the natural logarithm of N-terminal pro-B-type natriuretic peptide was added to the model.

CONCLUSION

Serum uric acid is a predictor of cardiac events and correlates to N-terminal pro-B-type natriuretic peptide and albuminuria, underscoring the importance of uric acid as a cardiovascular risk marker in patients with diabetes.

Efficacy of D-RaCe and ProTaper Universal Retreatment NiTi instruments and hand files in removing gutta-percha from curved root canals - a micro-computed tomography study

AIM

To compare the efficacy of two rotary NiTi retreatment systems and Hedström files in removing filling material from curved root canals.

METHODOLOGY

Curved root canals of 57 extracted teeth were prepared using FlexMaster instruments and filled with gutta-percha and AH Plus. After determination of root canal curvatures and radii in two directions, the teeth were assigned to three identical groups (n = 19). The root fillings were removed with D-RaCe instruments, ProTaper Universal Retreatment instruments or Hedström files. Pre- and postoperative micro-CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were analysed using analysis of covariance and analysis of variance procedures.

RESULTS

D-RaCe instruments were significantly more effective than ProTaper Universal Retreatment instruments and Hedström files (P < 0.05). Hedström files removed significantly less dentine than the rotary NiTi systems (P < 0.0001). D-RaCe instruments were significantly faster compared to both other groups (P < 0.05). No procedural errors such as instrument fracture, blockage, ledging or perforation were detected in the Hedström group. In the ProTaper group, four instrument fractures and one lateral perforation were observed. Five instrument fractures were recorded for D-RaCe.

CONCLUSIONS

D-RaCe instruments were associated with significantly less residual filling material than ProTaper Universal Retreatment instruments and hand files. Hedström files removed significantly less dentine than both rotary NiTi systems. Retreatment with rotary NiTi systems resulted in a high incidence of procedural errors.

The outcome of retained instrument removal in a specialist practice

AIM

To determine the success rate of a microendodontic technique for the removal of fractured instruments from root canals.

METHODOLOGY

Removal was attempted on a total of 170 consecutive referral cases with fractured instruments. All removal attempts were performed using an operating microscope and ultrasonic tips using a technique described by Ruddle (2003).

RESULTS

Of the 170 fractured instruments, 162 could be removed without perforation of the root canal, corresponding to a success rate of 95%. At a failure rate of 5%, eight instruments could not be removed, with root wall perforation occurring in one case. The lowest success rate of 93% was found in maxillary molars, the highest success rate of 100% in maxillary premolars and anterior and canine teeth of the maxillary and mandibular jaw. All removal failures occurred in cases where the fractured instruments were located apically or in the middle and apical part of the root. Regarding the angle of root canal curvature, the lowest success rates were found between 21 degrees and 50 degrees.

CONCLUSIONS

The position of the instrument within the root canal, the angle of the curvature of the root canal and the location of the fractured instrument in relation to the root canal curvature were the decisive factors that had a negative influence on the treatment outcome.The removal method tested represents a highly effective technique for the retrieval of fractured instruments.

Macrophage-modulating cytokines predict adverse outcome in heart failure

Cytokines regulating the mobilisation, recruitment and survival of mononuclear cells may play an important role in progression of heart failure. Therefore, we investigated the role of granulocyte colony stimulating factor (G-CSF), monocyte chemoattractant protein 1 (MCP-1) and macrophage colony stimulating factor (M-CSF) in patients with advanced heart failure. G-CSF, MCP-1 and M-CSF were determined in plasma of 351 patients with advanced heart failure by specific ELISAs. During a median follow up period of 16 months (95% confidence interval [CI]: 15-17 months) 175 patients (50%) experienced the composite endpoint rehospitalisation and all-cause mortality. M-CSF tertiles were associated with a gradually increasing risk with hazard ratios (HR) of 2.2 (95% CI: 1.5-3.2; for trend, p<0.001) for the composite endpoint and 2.6 (95% CI: 1.5-4.6; for trend, p=0.002) for all-cause mortality comparing third and first tertile. These associations remained significant in a multivariable Cox regression model after adjustment for BNP and other known risk factors (p=0.043 and p=0.024). High MCP-1 concentrations were associated with an increased risk of all-cause mortality with an adjusted HR of 1.9 (third vs. first tertile, 95% CI: 1.1-3.3; for trend, p=0.034). In contrast, G-CSF tertiles were not significantly associated with the composite endpoint or all-cause mortality in multivariable Cox regression. In conclusion, the independent and concentration-dependent association of macrophage-modulating cytokines and in particular of M-CSF with adverse outcome in advanced HF patients suggests that these cytokines may play an important pathophysiological role in progression of cardiomyopathy.

Outcome after device implantation in chronic heart failure is dependent on concomitant medical treatment

BACKGROUND

Device implantation in chronic heart failure (CHF) for cardiac resynchronization therapy (CRT) with or without implantable cardioverter/defibrillator (ICD) is an established treatment option for symptomatic patients under medical baseline therapy. Although recommended, the need for optimization of medical therapy was never proven. As in 'the real world', medical therapy is not always up-titrated to the desirable dosages; this provides the opportunity to evaluate the impact of optimizing medical therapy in patients who had received a device therapy with proven effectiveness.

MATERIALS AND METHODS

This observational cohort study retrospectively assessed the 'real life'-effect of CRT compared with that of CRT/ICD therapy and the impact of concomitant pharmacotherapy on outcome. Outcome of patients with guideline recommended renin-angiotensin system inhibitor and ss-blocker dosages was compared with that of patients who failed to reach the desired dosages. Mean follow-up for the 205 CHF (95 CRT and 110 CRT/ICD) patients was 16.8 + or - 12.4 months.

RESULTS

In the total study cohort, 83 (41%) reached the combined primary endpoint of all-cause death or cardiac hospitalization [CRT group: 25 (26%), CRT/ICD group: 58 (52.7%), P < 0.001]. Multiple cox regression analysis revealed non-optimized medical therapy at follow-up [HR = 2.080 (1.166-3.710), P = 0.013] and CRT/ICD vs. CRT [HR = 2.504 (1.550-4.045), P < 0.001] as significant predictors of the primary endpoint.

CONCLUSION

Our data stress the importance of professional monitoring and titration of pharmacotherapy not only in medically treated CHF patients but also in patients under device therapy by a heart failure unit or a specialized cardiologist.

Interactions of glucose metabolism and chronic heart failure

BACKGROUND

We evaluated insulin sensitivity and beta cell function in patients with chronic heart failure (CHF), and investigated a possible correlation of these metabolic parameters with specific biomarkers of heart failure. Additionally, we investigated the effects of two angiotensin receptor blockers (ARBs), namely telmisartan and candesartan, that were administered over a 5 month treatment period, as additional therapy to standard care.

METHODS AND RESULTS

The study group consisted of 94 CHF patients. Insulin sensitivity (OGIS index) and insulin secretion parameters were investigated by frequently sampled oral glucose tolerance tests and consecutive mathematical modelling. In total, 94.6 % of patients had clinically overt diabetes, impaired glucose tolerance or insulin resistance at the time of enrolment HbA1c was found to correlate to NT-proBNP, MR-proADM, CT-proET-1, and MR-proANP, but not to Copeptin. NT-proBNP correlated inversely to OGIS. None of the metabolic parameters were altered significantly after candesartan or telmisartan treatment in either the patient or standard care group.

CONCLUSION

Insulin sensitivity and insulin secretion are impaired in CHF and biomarkers of heart failure and atherosclerotic disease correlate to glucose metabolism.

Nonsurgical endodontic management of a double tooth: a case report

AIM

To present a case with various morphological irregularities requiring root canal treatment and to discuss the problems and options for orthograde root canal treatment.

SUMMARY

Root canal treatment of a double tooth presenting with an acute alveolar abscess is described. The anatomical variations of this tooth included double tooth, dental invagination, incomplete apical closure, three root canal systems and an internal lacuna. The tooth was treated nonsurgically with orthograde root canal treatment resulting in nearly complete radiographic apical repair after 4 years.

KEY LEARNING POINTS

*Double teeth occur infrequently and may be distinguished from fusion, gemination, concrescence and dental twinning. *Several malformations may be present in a single tooth. *Orthograde root canal treatment may be an adequate treatment option even in teeth with a complex internal anatomy.

Comparison of root canal preparation with two rotary NiTi instruments: ProFile .04 and GT Rotary

AIM

To compare root canal preparation using ProFile .04 and GT Rotary nickel-titanium instruments (both Dentsply Maillefer, Ballaigues, Switzerland).

METHODOLOGY

Fifty extracted mandibular molars with mesial root canal curvatures between 20 and 40 degrees were randomly divided into two groups and embedded in a muffle system. All root canals were prepared to size 45 using ProFile .04 or GT rotary instruments. The following parameters were evaluated: straightening of root canal curvature, postoperative root canal cross-section, cleaning ability, safety issues and working time.

RESULTS

Both NiTi systems maintained curvature well; the mean degree of straightening was <1 degrees . The majority of the root canals prepared with ProFile .04 (80.8%) and GT (84.0%) postoperatively showed a round or oval cross-section. For debris, ProFile .04 and GT rotary achieved 67.1% and 71.6% scores of 1 and 2, respectively. Concerning the coronal region statistical analysis showed a better result for GT than for ProFile .04. For the middle and apical thirds of the root canals, results did not differ significantly. None of the two systems completely removed smear layer. Ten procedural incidents occurred with ProFile .04 compared with five with GT. Mean working time was shorter for ProFile .04 (131.8 s) than for GT (143.7 s); the difference was not significant.

CONCLUSIONS

Both systems respected original root canal curvature well and were safe to use. Smear layer removal was not satisfactory with either systems.

Copeptin, a fragment of the vasopressin precursor, as a novel predictor of outcome in heart failure

BACKGROUND

Natriuretic peptides, particularly brain natriuretic peptide (BNP), are elevated in heart failure and therefore considered to be excellent predictors of outcome. Vasopressin is also known to be related to the severity of heart disease. Copeptin--an inactive fragment of the vasopressin precursor--has not been previously investigated in the context of heart failure.

MATERIALS AND METHODS

We prospectively studied 268 patients with advanced heart failure after they had been discharged from the hospital. We investigated the ability of BNP and copeptin to predict death, re-hospitalization due to heart failure, and a combination of the two endpoints.

RESULTS

Over a mean follow-up period of 15.8 months (up to 24 months), 83 patients died, 122 patients experienced worsening of heart failure, and 145 patients achieved the combined endpoint. Univariate predictors of death were copeptin, BNP, age and impaired kidney function. In multivariate analysis, copeptin (chi(2) = 16, P < 0.0001) and age (chi(2) = 4, P < 0.05) were independent predictors. Univariate predictors of re-hospitalization due to heart failure were copeptin, BNP, age and impaired kidney function. Furthermore, in multivariate analysis BNP (chi(2) = 18, P < 0.0001), age (chi(2) = 11.8, P < 0.001) and copeptin (chi(2) = 4.2, P < 0.05) were found to be independent predictors.

CONCLUSION

Our study is the first to show that copeptin is an excellent predictor of outcome in advanced heart failure patients. Its value is superior to that of BNP in predicting death and a combined endpoint, although BNP is still suitable for predicting chronic heart failure (CHF) re-hospitalization. Our data imply that vasopressin antagonism might be a new target to improve outcome in this population.

A comparative study of root canal preparation with NiTi-TEE and K3 rotary Ni-Ti instruments

AIM

To evaluate and compare several parameters of curved root canal preparation using two different Ni-Ti systems: NiTi-TEE (Sjöding Sendoline, Kista, Sweden) and K3 (Sybron Endo, Orange County, CA, USA).

METHODOLOGY

Fifty extracted mandibular molars with mesial root canal curvatures ranging from 20 to 40 degrees were divided into two groups. In one group, 50 root canals were instrumented using NiTi-TEE files to an apical size 30; 0.04 taper (the largest available size at the time of this study). In the other group, 50 root canals were prepared with K3 instruments to an apical size 45; 02 taper. Both systems were used in a crowndown manner, with copious NaOCl (3%) irrigation and a chelating agent (Calcinase Slide, lege artis, Dettenhausen, Germany), employing torque-controlled motors. For assessment of shaping ability, pre- and postinstrumentation radiographs and cross-sectional photographs of canals were taken and changes in canal curvature and root canal diameter documented. Cleaning ability was evaluated by investigating specimens of the apical, medial and coronal third of the root canal wall under a scanning electron microscope using 5-score indices for debris and smear layer. Procedural errors (instrument separations, perforations, apical blockages, loss of working length) and working time were recorded. Nonparametric anova was used to compare straightening of canal curvatures, canal cross-sections and canal wall cleanliness (P < 0.05), whereas working time was analysed using the parametric anova (P < 0.05).

RESULTS

Both Ni-Ti systems maintained curvature well: the mean degree of straightening was 0.2 degrees for NiTi-TEE and 0.4 degrees for K3 with no statistical significance between the groups. Post-instrumentation cross-sections of the root canals revealed an acceptable contour (round or oval) in 50.6% of cases for the NiTi-TEE group and in 65.3% of cases for the K3 group. The difference was not significant. The SEM investigation of canal walls showed equally good debris removal for both systems: NiTi-TEE prepared canal walls in 74.7% of cases with scores I and II; K3 achieved these scores in 78.7% of cases. For smear layer, NiTi-TEE and K3 only received good scores (I and II) in 38.7% and 40% of canal wall specimens, respectively. For both parameters, no significant differences were found between groups. File fractures did not occur, but loss of working length was observed in one case following the preparation with NiTi-TEE and in three cases during K3 instrumentation. Mean working time was significantly shorter for NiTi-TEE (170 s) than for K3 (208 s).

CONCLUSIONS

Both systems maintained original canal curvature well and were safe to use. Whilst debridement of canals was considered satisfactory, both systems failed to remove smear layer sufficiently.

Three-dimensional, non-destructive visualization of vertical root fractures using flat panel volume detector computer tomography: an ex vivoin vitro case report

AIM

To detect and to visualize radiographically vertical root fractures in extracted teeth with a prototype of a novel, high resolution, three-dimensional flat panel volume detector computer tomograph (FD-VCT) system.

SUMMARY

Five teeth with root fillings and clinical symptoms such as fistulas and isolated periodontal pockets of 8 mm or more were extracted after dental radiography indicating lateral or periapical lesions. Vertical root fractures or cracks were suspected because of the symptoms and clinical findings were evident after extraction in all cases but fracture lines were not visible on routine dental radiographs acquired before extraction. The extracted teeth were explored with a prototype of a FD-VCT. Using the FD-VCT, in all cases vertical root fractures or crack lines could be detected clearly in different views, depiction-modes and cross-sections at a spatial resolution of 140 microm. The evaluation of the fracture lines and teeth could be performed in three-dimensional views. The FD-VCT findings were confirmed by detailed inspection of the extracted teeth.

KEY LEARNING POINTS

The FD-VCT is an innovative diagnostic tool for non-destructive, three-dimensional evaluation of extracted teeth in pre-clinical and experimental studies. The FD-VCT allows precise visualization and evaluation of vertical root fractures or cracks in extracted teeth. Clinical application of the system may be possible if technical modifications reduce the exposure dose: the high resolution detector systems of the FD-VCT should be combined with radiation systems that focus the radiation to the area of interest.

Comparison of root canal preparation using RaCe and ProTaper rotary Ni-Ti instruments

AIM

To compare various parameters of root canal preparation using RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (Ni-Ti) instruments.

METHODOLOGY

Fifty extracted mandibular molars with mesial root canal curvatures between 20 degrees and 40 degrees were embedded in a muffle system. All root canals were prepared to size 30 using RaCe or ProTaper rotary instruments in low-torque motors with torque control and constant speed of 300 r.p.m. (ProTaper with ATR Tecnika, Advanced Technology Research, Pistoia, Italy; RaCe with EndoStepper, S.E.T., Olching, Germany). In both groups irrigation was performed with 2 mL NaOCl (3%) after each instrument size. Calcinase-Slide (lege artis, Dettenhausen, Germany) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal cross-sections, safety issues and working time. Cleanliness of the root canal walls was investigated under the SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the following tests: Wilcoxon's test for straightening and working time was used (P < 0.05); Fisher's exact test for comparison of cross-sections and root canal cleanliness (P < 0.05).

RESULTS

Both Ni-Ti systems maintained curvature well; the mean degree of straightening was less than 1 degrees for both systems. Following preparation with RaCe, 49% of the root canals had a round or oval diameter and 50% an irregular diameter, ProTaper preparations resulted in a round or oval diameter in 50% of the cases. For debris, RaCe and ProTaper achieved 47 and 49% scores of 1 and 2, respectively; there was no significant difference. For smear layer, RaCe and ProTaper achieved 51 and 33% scores 1 and 2, respectively; no statistically significant differences were apparent for the coronal and middle sections of the root canals, but RaCe performed significantly better in the apical region (Fisher's exact test, P = 0.0392). Two roots lost working length with RaCe instruments, whilst ProTaper preparation resulted in two roots loosing working length and one fractured instrument. Mean working time was shorter for ProTaper (90.9 s) than for RaCe (137.6 s); the difference was significant (Wilcoxon's test, P = 0.011).

CONCLUSIONS

Both systems respected original root canal curvature well and were safe to use. Cleanliness was not satisfactory for both systems.

Efficacy, cleaning ability and safety of different rotary NiTi instruments in root canal retreatment

AIM

To evaluate the efficacy, cleaning ability and safety of three different rotary nickel-titanium instruments with and without a solvent (eucalyptol) versus hand files in the removal of gutta-percha root fillings.

METHODOLOGY

Eighty extracted single-rooted anterior teeth were enlarged to size 35 and obturated with laterally condensed gutta-percha using AHPlus as the sealer. Removal of gutta-percha was performed with the following devices and techniques: FlexMaster, GT Rotary, ProTaper and Hedström files. All techniques were used with and without the solvent eucalyptol. The following data were recorded: time taken to reach the calculated working length and time required for the removal of gutta-percha. The teeth were split longitudinally and photographed. Cleanliness of the root canal walls was scored using the projected slides with a total magnification of approximately 70x. Statistical analysis was performed using the two-way anova (P < 0.001) for the analysis of working time.

RESULTS

The technique that reached the working length most rapidly was that using ProTaper instruments and eucalyptol (+E), followed by FlexMaster + E, ProTaper, FlexMaster, Hedström files + E, GT Rotary + E, Hedström files, and GT Rotary. No significant differences were found for retreatment with or without a solvent in all groups. ProTaper and FlexMaster worked significantly more rapidly than Hedström files and GT Rotary (anova, P < 0.001). Time for complete removal of gutta-percha was again shortest with ProTaper + E, followed by FlexMaster + E, ProTaper, FlexMaster, GT Rotary + E, Hedström files + E, Hedström files, and GT Rotary. ProTaper and FlexMaster again worked significantly faster than the other techniques (anova, P < 0.001). There was no visible filling material extruded apically. Root canal cleanliness proved best following the use of FlexMaster + E, and Hedström files + E, followed by ProTaper + E, and GT Rotary + E.

CONCLUSION

Under the experimental conditions, FlexMaster and ProTaper NiTi instruments proved to be efficient and time-saving devices for the removal of gutta-percha. The use of eucalyptol as a solvent shortened the time to reach the working length and to remove the gutta-percha, but this was not significant.

Diagnosis and root canal treatment of a mandibular second premolar with three root canals

AIM

To present a case of a mandibular second premolar with three root canals.

SUMMARY

An accurate diagnosis of the morphology of the root canal system is a prerequisite for successful root canal treatment. A review of the literature reveals a low incidence of all types of premolars with three root canals. Diagnostic means such as preoperative radiographs and examination of the pulp chamber floor aid the location of root canal orifices. The diagnostic and therapeutic problems concerning premolars with unusual anatomy are described on the basis of a clinical example. A case report describes the successful treatment of a mandibular second premolar with three root canals.

KEY LEARNING POINTS

Clinicians should be aware of unusual root canal anatomy in mandibular premolars. Radiographs exposed at two different horizontal angles and their careful interpretation facilitate the search of additional root canals. The use of magnification and additional lighting are recommended for the clinical examination of the pulpal floor.

Chelating agents in root canal treatment: mode of action and indications for their use

Chelating agents were introduced into endodontics as an aid for the preparation of narrow and calcified root canals in 1957 by Nygaard-Østby. A liquid solution of ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften the root canal dentine and dissolve the smear layer, as well as to increase dentine permeability. Although the efficacy of EDTA preparations in softening root dentine has been debated, chelator preparations have regained popularity recently. Almost all manufacturers of nickel-titanium instruments recommend their use as a lubricant during rotary root canal preparation. Additionally, a final irrigation of the root canal with 15-17% EDTA solutions to dissolve the smear layer is recommended in many textbooks. This paper reviews the relevant literature on chelating agents, presents an overview of the chemical and pharmacological properties of EDTA preparations and makes recommendations for their clinical use.

Chelating agents in root canal treatment: mode of action and indications for their use

Chelating agents were introduced into endodontics as an aid for the preparation of narrow and calcified root canals in 1957 by Nygaard-Østby. A liquid solution of ethylenediaminetetraacetic acid (EDTA) was thought to chemically soften the root canal dentine and dissolve the smear layer, as well as to increase dentine permeability. Although the efficacy of EDTA preparations in softening root dentine has been debated, chelator preparations have regained popularity recently. Almost all manufacturers of nickel-titanium instruments recommend their use as a lubricant during rotary root canal preparation. Additionally, a final irrigation of the root canal with 15-17% EDTA solutions to dissolve the smear layer is recommended in many textbooks. This paper reviews the relevant literature on chelating agents, presents an overview of the chemical and pharmacological properties of EDTA preparations and makes recommendations for their clinical use.

Comparative study of root-canal preparation using Lightspeed and Quantec SC rotary NiTi instruments

AIM

To compare several parameters of root-canal preparation using two different rotary nickel-titanium (NiTi) instruments: Lightspeed (Lightspeed Inc, San Antonio, TX, USA) and Quantec SC (Tycom, Irvine, USA).

METHODOLOGY

Fifty extracted mandibular molars with root-canal curvatures between 20 degrees and 40 degrees were embedded into a muffle system. All root canals were prepared to size 45 followed by a stepback in 1-mm increments to size 70 (Lightspeed) or 45 (Quantec SC), using a high-torque motor at 1300 or 350 r.p.m. respectively. In both groups, irrigation was performed with 2 mL NaOCl (3%) after each instrument size. RC-Prep (Premier, PA, USA) was used as a chelating agent. The following parameters were evaluated: straightening of curved root canals, postoperative root-canal diameter, working safety (instrument fractures, perforations, apical blockages, loss of working length (WL)), cleaning ability and working time. Cleanliness of the root-canal walls was investigated under SEM using 5-score indices for debris and smear layer. Statistical analysis was performed using the Wilcoxon's test (P < 0.05) for straightening and Fisher's exact test (P < 0.05) for comparison of cross-sections, contact between pre- and postoperative diameter, root-canal cleanliness and working time.

RESULTS

Both NiTi systems maintained the curvature well: the mean degree of straightening was 1.8 degrees for Lightspeed and 1.7 degrees for Quantec SC; differences were not significant. Procedural incidents occurred with Quantec SC in 12 root canals (three fractures, four apical blockages and five cases of loss of WL), preparation with Lightspeed resulted in five fractures, one apical blockage and five cases of loss of WL (11 incidents). Following preparation with Lightspeed, 55.5% of the root canals had a round diameter, 25% an oval and 19.5% an irregular diameter; Quantec SC preparations resulted in a round diameter in 51.5%, oval shape in 33.3% and irregular cross-sections in 15.2% of the cases. Mean working time was similar for Quantec SC (161 s) and Lightspeed (155 s); the difference was not significant. For debris, Lightspeed and Quantec achieved 64 and 63% for scores 1 and 2, respectively. For smear layer, Lightspeed and Quantec achieved only 13.3 and 27.4% for scores 1 and 2, respectively. Differences were not significant for either debris or smear layer.

CONCLUSIONS

Both systems respected original root-canal curvature well and prepared acceptable diameter forms. The cleaning ability was judged not satisfactory for both systems. Both systems showed deficiencies in working safety.

A comparative study of root canal preparation using FlexMaster and HERO 642 rotary Ni-Ti instruments

AIM

To compare several parameters of root canal preparation using two different rotary nickel-titanium (Ni-Ti) instruments: FlexMaster (VDW, Munich, Germany) and HERO 642 (Micro-Mega, Besançon, France).

METHODOLOGY

Fifty extracted human mandibular molars with root canal curvatures between 20 and 40 degrees were embedded into a muffle system. All root canals were prepared to size 45 using a high-torque motor with two different Ni-Ti instruments, FlexMaster and HERO 642. In both groups, irrigation was performed with 2 mL NaOCl (3%) after each instrument size. RC-Prep (Premier, Philadelphia, USA) was used as a chelating agent with each instrument. The following parameters were evaluated: straightening of curved root canals, postoperative root canal diameter, working safety (file fractures, perforations, apical blockages, loss of working length), cleaning ability and working time. Statistical analysis was performed using the Wilcoxon's test (P < 0.05) for straightening and Fishers's exact test (P < 0.05) for comparison of cross-sections, contact between pre- and postoperative diameter, root canal cleanliness and working time.

RESULTS

Both Ni-Ti systems maintained the curvature well: the mean degree of straightening was 0.6 degrees for FlexMaster and 0.5 degrees for HERO 642. One file was fractured with the FlexMaster system, but further procedural incidents were not recorded. Following preparation with FlexMaster, 18% of the root canals had a round diameter, 53% an oval diameter and 29% an irregular diameter; HERO 642 preparations resulted in a round diameter in 25%, oval shape in 47% and irregular cross-sections in 28% of the cases. Mean working time was shorter for HERO 642 (66.0 s) than for FlexMaster (71.1 s). Cleanliness of the root canal walls was investigated under the SEM using 5-score indices for debris and smear layer. For debris, HERO 642 and FlexMaster achieved 73 and 70% scores of 1 and 2, respectively. The results for smear layer were similar: HERO 642 and FlexMaster achieved 33 and 26% scores of 1 and 2, respectively. Significant differences between the two systems were not detected for any of the parameters evaluated.

CONCLUSIONS

Both systems respected original root canal curvature well and were safe. Both systems failed to remove debris and smear layer in the majority of the cases.

Prophylactic anticoagulation with enoxaparin: Is the subcutaneous route appropriate in the critically ill?

BACKGROUND

Subcutaneously administered low-molecular-weight heparins are widely used for prevention of venous thromboembolism. The appropriateness of the subcutaneous route in critically ill patients has never been established.

OBJECTIVE

To determine anti-Xa activities in critically ill patients and in noncritically ill patients receiving prophylactic doses of subcutaneous enoxaparin.

DESIGN

Prospective, controlled, open-labeled study.

SETTING

Tertiary medical-cardiologic-postoperative intensive care unit and a general medical ward at a university hospital.

PATIENTS

A total of 16 intensive care unit patients (group 1; age, 61.1 +/- 16 yrs; male/female ratio, 7/9; Acute Physiology and Chronic Health Evaluation II score, 20.9 +/- 7; mechanical ventilation, n = 15; vasopressors, n = 13) and 13 noncritically ill medical patients (group 2; age, 61.7 +/- 9 yrs; male/female ratio, 7/6) were studied. Body mass index (25.7 +/- 5 vs. 24 +/- 6 kg/m2, p = not significant) was comparable and serum creatinine levels (0.83 +/- 0.25 vs. 1.07 +/- 0.3 mg/dL, group 1 vs. 2) were within the normal range in both groups. Patients with impaired renal function, receiving hemofiltration, or requiring therapeutic anticoagulation were not eligible.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Anti-Xa activities were determined at 0, 1, 3, 6, and 12 hrs after a single daily subcutaneous dose of 40 mg enoxaparin on day 1 and at 3 hrs after 40 mg of enoxaparin on days 2-5. Mean anti-Xa levels at 0 to 12 hrs were consistently lower in group 1 compared with group 2 by analysis of variance (p =.001 between groups and over time), as was the area under the curve at 0 to 12 hrs (2.6 +/- 1 vs. 4.2 +/- 1.7 units x mL(-1) x hr(-1), group 1 vs. 2, p =.008). Significant differences in anti-Xa activity were also found on days 2-5 (p =.001). Peak anti-Xa activities at 3 hrs after administration were negatively correlated with the body mass index (r = -.41, p <.03). No correlation was found between the anti-Xa activity at 3 hrs and the dose of norepinephrine (r =.12, p =.7).

CONCLUSION

Critically ill patients with normal renal function demonstrated significantly lower anti-Xa levels in response to a single daily dose of subcutaneous enoxaparin when compared with medical patients in the normal ward.

Quality of preparation of oval distal root canals in mandibular molars using nickel-titanium instruments

AIM

The aim of this study was to compare the preparation of oval distal root canals in mandibular molars using three different nickel-titanium (NiTi) instruments: Lightspeed (Lightspeed Inc., San Antonio, TX, USA). ProFile .04 (Maillefer Ballaigues. Switzerland) and Quantec SC (Tycom, Irvine, CA, USA).

METHODOLOGY

Three groups of 20 extracted mandibular molars with oval distal root canals were embedded in a muffle system as described by Bramante et al. (1987) and modified by Hülsmann et al. (1999). Preparation of the root canals was performed with particular emphasis on the buccal and lingual extensions of the oval shape. The following parameters were evaluated: comparison of pre- and postoperative photographs with regard to the buccal and lingual extensions of the preparation, safety issues (file fractures, perforations, apical blockages, loss of working length), cleaning ability (SEM investigated using a 5-score system for remaining debris and smear layer) and working time.

RESULTS

Superimposition of pre- and postoperative cross-sections in the majority of specimens revealed uninstrumented or incompletely instrumented buccal or lingual extensions (Lightspeed and Quantec SC, 56.7%; ProFile .04, 55%) For debris removal, Quantec SC achieved the best results (54.2% scores 1 and 2), followed by ProFile .04 (52.5%) and Lightspeed (46.7%). Preparation resulted in substantial smear layer covering the canal walls for every system (ProFile .04, 38.3%; Quantec SC, 36.6%; Lightspeed, 28.3%). Differences between the three systems were not significant for any of the parameters investigated. Preparation with Lightspeed resulted in two fractured instruments; with Quantec SC. two apical blockages occurred. With ProFile .04, no complications were noticed. Mean working time was shorter for ProFile .04 (261.2 s) than for Quantec SC (272.4 s) and Lightspeed (338.9 s); the differences were not significant.

CONCLUSIONS

The flexibility of the NiTi instruments investigated in this study did not allow controlled preparation of the buccal and lingual extensions of oval root canals. The instruments frequently produced a circular bulge in the canal whilst the buccal and lingual extensions remained unprepared, leaving smear layer and debris.

Comparative in-vitro evaluation of three chelator pastes

AIM

To compare the effect of three paste chelating agents on the root dentine of extracted teeth: Calcinase-Slide (lege artis, Dettenhausen, Germany), Glyde-File (DeTrey/Dentsply, Konstanz, Germany), RC-Prep (Premier, Norristown, USA).

METHODOLOGY

Ten slices of root dentine were covered with one of the chelating agents for 30 s, 1 min and 2 min and irrigated with 5 mL H2O2 and NaOCl. This was repeated five times. Pre- and postoperative Vickers hardness of root dentine was measured. Twenty slices of root dentine were covered with 0.1 mL of the chelating agents for 3, 6 and 9 min. Differences between pre- and postoperative weight were recorded. Ten root canals of extracted teeth were enlarged five ISO-sizes with 0.1 mL chelator paste for each file. The teeth were split longitudinally and cleanliness of the root-canal walls was evaluated under the SEM using a four-score evaluation index. Results were statistically analysed using the Wilcoxon-Mann-Whitney test, the Friedman test and the Kruskal-Wallis test with P<0.05 for all tests.

RESULTS

No significant differences between the chelating agents were found in terms of changes in dentine hardness. Loss of hardness increased significantly with increasing time of contact of the chelating pastes with dentine. There were significant differences between the three chelating agents and the control for loss of weight. After 3 min there was no significant difference between the chelating agents, after 6 and 9 min Calcinase-Slide showed significantly more weight loss than RC-Prep; after 6 min Glyde-File showed significantly more weight loss than RC-Prep. In the coronal and middle parts of the root canals, the cleaning ability of Calcinase-Slide was significantly better than of RC-Prep and Glyde-File; in the apical third no differences could be found.

CONCLUSIONS

Under the circumstances of this in vitro study, the three chelator pastes evaluated had no or only slight differences in terms of weight loss, changes of Vickers hardness in root dentine and cleanliness of root-canal walls. The use of a chelating agent may be useful to enhance cleanliness of the coronal and middle part of the root canal.