Effectiveness of D,L-2-hydroxyisocaproic acid (HICA) and alpha-mangostin against endodontopathogenic microorganisms in a multispecies bacterial-fungal biofilm in an ex vivo tooth model.

AIM: To develop a defined multispecies root canal biofilm model ex vivo, and to perform viable compositional analysis following D,L-2-hydroxyisocaproic acid (HICA), alpha-mangostin, Calcicur® , and Odontopaste® exposure. METHODOLOGY: Time-kill assays were conducted in vitro using HICA, alpha-mangostin, Calcicur® , Odontopaste® , and saline solution on the planktonic cultures of C. albicans, E. faecalis, L. rhamnosus, and S. gordonii. Human root dentine blocks were prepared (n = 100) ex vivo, and multispecies suspensions containing each of 1.5 × 108  CFU/mL C. albicans, E. faecalis, L. rhamnosus, and S. gordonii in brain heart infusion (BHI) were incubated within the root canals for 21 days. Canals (n = 20/group) were then exposed to medicaments for 7 days. Samples taken from the inner (first 0.1 mm) and deeper (second 0.1 mm) dentine by drilling with Ash Steel Burs No. 5 and No. 6, and residual roots were cultured in broth for 24 h. Cell growth was detected by spectrophotometry and confirmed by culture on agar. The other set of inner dentine, deeper dentine, and residual root samples were sonicated, and then exposed with 50 µM PMA before DNA was extracted using the QIAamp DNA mini kit. Real-time quantitative PCR was performed to determine the biofilm composition as well as the number of live and total cells remaining in the biofilm following each treatment. The OD data were analysed with Kruskal-Wallis and Friedman with Wilcoxon signed-rank test between and within groups, respectively, agar culture and qPCR data with Pearson chi-square with Mann-Whitney and Cochran with McNemar tests, respectively (p < .0001). RESULTS: Time-kill assays revealed that HICA and Calcicur® killed all planktonic organisms within 24 h, whilst alpha-mangostin killed the organisms within 72 h. However, Odontopaste® was a slow-killing agent: 10 cells of planktonic organisms survived after exposure to the agent for 7 days. The ex vivo tooth model demonstrated that HICA and alpha-mangostin significantly inhibited the cell growth in all sampling depths (p < .0001). All species-specific data revealed the effectiveness of each medicament on the biofilm composition. CONCLUSIONS: D,L-2-hydroxyisocaproic acid and alpha-mangostin had antimicrobial activity against multispecies bacterial-fungal biofilms.

WITHDRAWN: Pulp management for caries in adults: maintaining pulp vitality.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 METHODS: 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 Collaboration'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.

Modern Endodontic Principles. Part 8: The Future of Endodontics.

Although the principles of endodontics have remained unchanged for many decades, root canal treatment has been subject to major changes in the past few years. This paper outlines the cutting-edge advances including the materials and techniques used. CPD/Clinical Relevance: This article provides an overview of bioactive materials and insight into regenerative endodontics, vital pulp therapy and intentional replantation.

Modern Endodontic Principles. Part 6: Managing Complex Situations.

Clinicians are often faced with endodontic cases that are significantly more challenging than the primary root canal treatment of mature adult teeth. This paper outlines some of the common treatment modalities which can be employed in situations in which either primary treatment has failed, or there is iatrogenic damage or unusual anatomy. CPD/Clinical Relevance: This paper will provide the reader with advice and techniques for undertaking orthograde endodontic retreatment, hemisection, endodontic surgery and management of teeth with incompletely formed roots.

Modern Endodontic Principles Part 7: The Restorative Interface.

The restoration of endodontically-treated teeth is a topic that has been extensively studied and yet remains controversial. The endodontically-treated tooth can be restored with a wide range of techniques of varying complexity. This article reviews the literature on this topic. Consideration is given to the ferrule and its importance in achieving success. Furthermore, consideration will be given to the use of endodontically-treated teeth as abutments for fixed and removable prostheses and the challenges this presents. Clinical recommendations are presented as guidelines to improve the predictability and outcome of treatment when restoring structurally compromised root-filled teeth. Clinical relevance: The prognosis of endodontically-treated teeth depends not only on the success of the endodontic treatment, but also on the type of reconstruction.

Root Resorption: Simplifying Diagnosis and Improving Outcomes.

Root resorption is a condition resulting in the progressive loss of dental hard tissue. It may occur both within the root and upon the external aspect of the root. Diagnosis can be difficult and management challenging. Understanding the pathology is critical to understanding why and when this disease occurs and what the best management techniques involve. With such knowledge practitioners can confidently diagnose resorption, discuss prognoses and management strategies with the patient and either refer or begin treatment. Early intervention is paramount in improving outcomes. As such, if practitioners choose to refer patients they must be aware of what can be done immediately to mitigate risks until consultation and specialist treatment begins.

Modern Endodontic Planning Part 1: Assessing Complexity and Predicting Success.

Following a diagnosis of irreversible pulpal disease, periapical disease or failed endodontic therapy, the options for the tooth are extraction or root canal treatment. There is increasing evidence that certain factors may allow the clinician to predict the likely outcome of root canal therapy (RCT) and thus better inform the patient of the possible success rates. Should the patient choose root canal treatment, the clinician must also be able to gauge the potential difficulties that may be encountered and consequently determine whether it is within their competency. CPD/CLINICAL RELEVANCE: Assessing outcomes and complexity of care is an essential part of informed consent. Knowing when to refer is an essential component of best clinical practice.

Micro-CT evaluation of the effectiveness of the combined use of rotary and hand instrumentation in removal of Resilon.

This study compares the effectiveness of ProTaper rotary files with ProTaper retreatment and K-files in the removal of Resilon or gutta percha (GP) from canals filled either by cold lateral condensation or thermal obturation using micro-CT. Ninety-six teeth were prepared using ProTaper files and allocated into four groups (n=24): Group-1 was filled with GP/AH-Plus and Group-2 with Resilon/RealSeal using cold lateral condensation. Group-3 was filled with GP/AH-Plus and Group-4 with Resilon/RealSeal using System B and Obtura II. The roots were scanned by micro-CT. Each group was divided into two subgroups (n=12): A, retreated using ProTaper files and B, using ProTaper retreatment and K-files. The roots were scanned to calculate the volume of the remaining material. With thermal obturation, roots filled with Resilon had significantly more remaining material than GP. Obturation using thermal technique resulted in significantly less remaining material than cold condensation except Resilon retreated using ProTaper retreatment and K-files.

Resistance to vertical fracture of MTA-filled roots.

AIM: To investigate the effect of MTA root canal fillings on the resistance to vertical root fracture (VRF) over different time intervals. MATERIAL AND METHODS: Freshly extracted anterior human teeth with single canals and minimal curvatures were decoronated, instrumented to size 50/.05 ProTaper file, irrigated with 1%NaOCl and randomly allocated to one of three groups (n = 36): (i) filled with MTA, (ii) filled with gutta-percha and sealer and (iii) unfilled roots used as a negative control. Each group was subdivided into three subgroups (n = 12) according to the storage time of 48 h, 1 and 6 months at 37°C in synthetic tissue fluid (STF). Following the storage periods, filled roots were mounted in acrylic supports, and the periodontal ligament was simulated using elastomeric impression material. Vertical loading was carried out with a ball-ended steel cylinder fitted on a universal testing machine at 1 mm/min crosshead speed. The maximum force at fracture (F-max) and the fracture mode were recorded for each root. RESULTS: Data were statistically analysed using two-way anova and Bonferroni post hoc tests. The mean F-max was significantly higher in the MTA subgroups after 1 and 6 months compared with all other subgroups. Two modes of fracture were identified: split and comminuted. The mean F-max values recorded with the latter were significantly higher compared with the former (P < 0.001). In all groups, split fracture was the most dominant mode apart from the MTA/1 month and MTA/6 month groups. CONCLUSION: MTA increases the resistance to VRF of endodontically treated teeth and influences the mode of fracture after 1 and 6 month of storage in STF compared with gutta-percha and sealer.

The effect of smear layer on the push-out bond strength of root canal calcium silicate cements.

INTRODUCTION: The aim of this study was to evaluate the effect of smear layer removal on the push-out bond strength between radicular dentin and three calcium silicate cements (CSC) in comparison with gutta percha and sealer. METHODS: Eighty human anterior extracted teeth were decoronated, cleaned and shaped to size 50/0.05 apically and randomly divided into 2 major groups: (A) smear layer preserved, and (B) smear layer removed using irrigation with 17% EDTA. Roots within each major group were further divided into 4 subgroups according to the obturation material used: (1) ProRoot MTA, (2) Biodentine, (3) Harvard MTA, (4) Gutta percha and AH-plus sealer. Obturated roots were stored in synthetic tissue fluid for 7 days to allow maximum setting of the root filling materials. Three 2-mm-thick slices were obtained from each root at different section levels (coronal, middle, apical). The canal diameters and slice thickness were measured, and the adhesion surface area for each slice was calculated. Push-out bond strength test was carried out using a universal testing machine. The bond failure mode was assessed under an optical microscope at 40×. RESULTS: The mean push-out bond strength in groups 1A, 2A and 3A were 7.54 (±1.11), 7.64 (±1.08) and 8.79 (±1.55)MPa respectively, while those for groups 1B, 2B and 3B were 6.58 (±1.13), 6.47 (±1.08), 7.71 (±1.81)MPa, respectively. In the gutta percha and sealer groups the push-out bond strength means were: 1.98 (±0.48) and 2.09 (±0.51)MPa in the preserved and removed smear layer groups respectively. The push-out strength values were significantly reduced when the smear layer was removed in the CSC groups (P<0.05) while no significant difference was detected in the gutta percha and sealer groups. CONCLUSIONS: Based on the conditions of this ex vivo study, it can be concluded that smear layer removal is detrimental to the bond strength between calcium silicate cements and dentin.

A micro-computed tomography evaluation of mineral trioxide aggregate root canal fillings.

INTRODUCTION: The aim of this study was to assess the effect of indirect ultrasonic activation on the incidence of voids within mineral trioxide aggregate (MTA) root canal fillings and at their interface with the canal walls by using a nondestructive 3-dimensional (3D) micro-computed tomography (micro-CT) analysis. METHODS: Extracted human teeth with single canals and minimal curvatures were decoronated, instrumented to size 50/05 apically, and randomly allocated into 4 groups (n = 12). MTA was compacted manually by using hand pluggers in group A (MC). Indirect ultrasonic activation was applied to each increment of manually compacted MTA for 1 second in group B (1 sec-UC), 5 seconds in group C (5 sec-UC), and 10 seconds in group D (10 sec-UC). Filled roots were scanned with a micro-CT device, and 3D analysis of void incidence was carried out by using the SkyScan software. RESULTS: Statistical analysis showed a significantly lower incidence of voids (P < .05) in the manual compaction (MC) group (0.7%) compared with the ultrasonic activation for 1 second (3.8%), 5 seconds (1.7%), and 10 seconds (1.6%) groups. CONCLUSIONS: Manual compaction produced significantly denser root fillings than those achieved with ultrasonic activation.

Endodontics and the older patient.

UNLABELLED: The number of elderly people in the population is rising and there is an increasing trend for tooth preservation. Older patients are more likely to have complex medical histories and/or physical disabilities. They are increasingly likely to retain their teeth, which could be heavily restored or broken down and root treatment may be challenging. In order to maintain teeth, a decision needs to be made as to whether or not to carry out endodontic treatment, which may be challenging in itself, and may also be associated with other age-related considerations. This paper considers endodontic issues related to the older patient, bearing in mind the plethora of considerations which may be relevant to root canal treatment. CLINICAL RELEVANCE: There are many benefits of retaining teeth, but there may be disadvantages.

Efficiency of a newly designed ultrasonic unit and tips in reducing temperature rise on root surface during the removal of fractured files.

INTRODUCTION: A potentially damaging temperature rise within the root canal and thus on the external root surface may be induced because of frictional contact of ultrasonic tips during the removal of separated instruments. The efficiency of a new ultrasonic unit, with air-spray function and ET40D (Satelec/Acteon, Merignac, France) and CPR5 (Obtura-Spartan, Fenton, MO) ultrasonic tips, in reducing temperature rise on the external root surface during the removal of fractured files was investigated. METHODS: Four millimeters of F2 ProTaper files (Dentsply, Surrey, UK) were fractured 2.5 mm from the canal access of 60 lower incisor roots. Roots were randomly divided into six groups: groups CPR5/no air and ET40D/no air in which tips were used without air flow, groups CPR5/15 psi and ET40D/15 psi (tips used with 15-psi air pressure), and groups CPR5/10 psi and ET40D/10 psi (10-psi air pressure). The temperature rise was measured on the external proximal root surface, adjacent to the most coronal aspect of the fractured fragment, at 15 seconds and then at 30-second intervals up to 120 seconds. RESULTS: After 120 seconds, the mean temperature rise (4.2 degrees C) with the air flow active was significantly lower than that with nonactive air flow (11 degrees C). At 10- and 15-psi pressures, the temperature rise after 120 seconds induced by ET40D tips was 4 degrees and 2.4 degrees C, respectively. These were significantly lower than with CPR5 tips (6.3 degrees and 4.2 degrees C, respectively). CONCLUSIONS: A new ultrasonic unit incorporating an air-flow function proved to be effective in reducing the temperature rise during removal of fractured files. ET40D ultrasonic tips were more effective than the CPR5 tip. However, both tips could be safely activated with air spray up to 120 seconds.

Evaluation of root canal obturation: a three-dimensional in vitro study.

The aim of the study was to measure percentage of volume of voids and gaps in root canals obturated with different obturation materials by using micro-computed tomography (micro-CT). Forty-eight single-rooted teeth were collected and decoronated, and root canals were prepared by using rotary files. The roots were randomly allocated into 4 groups, and each group was obturated by using cold lateral compaction with a different material (gutta-percha and TubliSeal sealer, EndoRez points and EndoRez sealer, RealSeal points and RealSeal sealer, and a gutta-percha point and GuttaFlow sealer). Roots were scanned with micro-CT, and volume measurements for voids and gaps in the obturated roots were carried out by using specialized CT software. Percentage of gaps and voids was calculated. Statistical analysis showed that gutta-percha exhibited an overall significantly lower percentage (1.02%) of voids and gaps. The present study showed that none of the root canal filled teeth were gap-free. Roots filled with gutta-percha showed less voids and gaps than roots filled with the remaining filling materials.

A novel instrument to determine pulp proximity.

The aim was to determine whether extracted teeth could be used to test the Prepometer instrument, which indicates pulp proximity with green/amber/red light emitting diodes. Third molars were reduced to a plane in dentine and Prepometer readings made. Dentine was removed in 0.5 mm increments and readings made until only lights 9 or 10 (red) showed. The teeth were sectioned and the dentine thickness measured. Analysis permitted construction of a highly significant predictor-model (p < 0.01), the red/amber light boundary coinciding with a dentine thickness of 2.4 mm. The Prepometer was consistent in predicting pulp proximity but was more sensitive than specified.

A microcomputed tomography scanning study of root canal space: changes after the ultrasonic removal of fractured files.

This in vitro study aimed to investigate the effect of ultrasonic removal of endodontic fractured files on tooth structure. Fifty-three canine roots were cleaned and weighed. They were scanned by a microcomputed tomography scanner producing two-dimensional images that were reconstructed into two-dimensional slices, and, finally, the canal volume was measured. In a control group, canals were prepared to F5-size ProTaper (Dentsply Ltd, Surrey, UK). In three experimental groups, F5-fractured files were ultrasonically removed from three root canal locations: coronal, middle, and apical. All roots were reweighed and rescanned. Reconstruction and analysis were performed to remeasure the canal volume. The differences in root mass (weight) and canal volume between before and after treatment were calculated. The highest change increase in canal volume was found when fractured files were removed from the apical part followed by middle and coronal. A positive correlation existed between canal volume and root mass changes. Microcomputed tomography scanning can reliably determine changes in canal volume resulting from fractured-file removal.

Time-dependence of coronal seal of temporary materials used in endodontics.

The aim of this in vitro study was to compare parametrically the coronal seal ability over different periods of times of four restorative materials used to seal the pulpal access cavity after endodontic treatment. One hundred and thirty-five mandibular premolars were divided randomly into three time groups (1, 2 and 4 weeks), each of which was in turn divided into four subgroups. Each subgroup was restored using one of four restorative materials: Coltosol, glass ionomer cement (GIC), zinc phosphate (ZP) cement, or intermediate restorative material (IRM) cement. The root canals were prepared using the crown-down technique, and obturated using lateral condensation. Following placement of the restorative material, the samples were incubated in distilled water at 37 degrees C and were subjected to 50 thermocycles (0 +/- 4, 56 +/- 4C). After immersing in (2%) methylene blue dye for 24 h, teeth were longitudinally sectioned and examined under a stereomicroscope. The results showed that Coltosol and GIC cement were significantly superior in sealing ability to ZP and IRM cements (P < 0.05). There was no significant difference between GIC cement and Coltosol. Both Coltosol and GIC after 1 week were significantly better than 4 weeks. There was no significant difference in the seal ability at different time periods when ZP and IRM cements were used.

Three-dimensional evaluation of effectiveness of hand and rotary instrumentation for retreatment of canals filled with different materials.

The aim of this study was to measure the remaining filling volume of different obturation materials from root-filled extracted teeth by using 2 removal techniques. Eighty single-rooted teeth were collected and decoronated, and the root canal was prepared by using the ProTaper nickel-titanium rotary files. The teeth were randomly allocated into 4 groups, and each group was obturated by using a different material. Group 1 was filled with gutta-percha and TubliSeal sealer, group 2 was filled with EndoRez points and EndoRez sealer, group 3 was filled with RealSeal points and RealSeal sealer, and Group 4 was filled with a gutta-percha point and GuttaFlow sealer. Teeth were scanned with a micro-computed tomography scan, and then root fillings were removed by using ProTaper retreatment files or hand K-files. Teeth were scanned again, and volume measurements were carried out with micro-computed tomography software. Statistical analysis showed significant differences between the 2 removal techniques for gutta-percha and for both techniques between gutta-percha and the other groups. The present study showed that all tested filling materials were not completely removed during retreatment by using hand or rotary files. Gutta-percha was more efficiently removed by using hand K-files.

Is a "flexible" glass fiber-bundle dowel system as retentive as a "rigid" quartz fiber dowel system?

PURPOSE: This study had two aims: (1) to compare the retention of a flexible directly placed fiber-bundle dowel system with that of a rigid prefabricated fiber-reinforced composite (FRC) dowel system, and (2) to determine the effect of decreasing the volume of luting cement around the flexible fiber-bundle dowels on the axial retention of the restorations. MATERIALS AND METHODS: Single-canal premolars (n = 36) were decoronated, cleaned, shaped, and prepared for both flexible and rigid dowels to a depth of 10 mm using a size 2 drill. The roots were then randomly allocated into three groups: Ia, Ib, and II (n = 12). Flexible fiber-bundle dowels were placed in groups Ia and Ib. These were available in three fiber-bundle diameters: small (0.9 mm), medium (1.2 mm), and large (1.5 mm). These bundles were luted in the root canals with Variolink II. The differences between Ia and Ib were in the ratio of the volume of fiber-bundles to the volume of luting cement and in the mode of application. Medium fiber-bundles were placed to the end of the preparation in groups Ia and Ib; however, in group Ia, a small diameter auxiliary bundle was placed, whereas in group Ib, a large-diameter auxiliary bundle was cut axially into strips of circa 0.2-mm thickness before being sequentially overlapped in placement. Roots in group II were restored with size 2 rigid prefabricated fiber dowels and luted with the light-cured cement provided by the manufacturer. After 24 hours of storage, axial tensile forces were applied to all luted dowels progressively to failure at 0.5 mm/min. Data were analyzed using a one-way analysis of variance (ANOVA) and the Bonferonni test. RESULTS: The mean axial resistance forces (standard deviation [SD]) for groups Ia, Ib, and II were not statistically different at 166 (49), 157 (36), and 151 (44) N, respectively (p > 0.05). CONCLUSIONS: There was no significant difference between the retention of the flexible fiber-bundle dowel system and that of the rigid prefabricated fiber dowel system. Decreasing the volume of luting cement around the flexible dowels did not have a significant effect on the axial retention of the restorations.