Chankhrit Sathorn

Impact of a Retained Instrument on Treatment Outcome: A Systematic Review and Meta-analysis

INTRODUCTION Fracture of root canal instruments is one of the most troublesome incidents in endodontic therapy. This systematic review and meta-analysis aim to determine the outcome difference between retained fractured instrument cases and matched conventional treated cases. METHODS The MEDLINE database, EMBASE, Web of Science, and the Cochrane Database were searched. Reference lists were scanned. A forward search was undertaken on identified articles. Papers citing these articles were identified through Science Citation Index to identify potentially relevant subsequent primary research. A systematic data extraction sheet was constructed. Data in these studies were independently extracted. Risk differences of included studies were combined by using the generic inverse variance data and fixed effects method. A 2-stage analysis was conducted. The first was limited to case-control studies, and the second included case series in which data were available for teeth with and without periradicular lesions. RESULTS Two case-control studies were identified and included, covering 199 cases. Weighted mean healing for teeth with a retained instrument fragment was 91%. The 2 studies were homogeneous. Risk difference of the combined data was 0.01, indicating that a retained fragment did not significantly influence healing. Overall, 80.7% of lesions healed when a periapical lesion was present, compared with 92.4% remaining healthy when no lesion was present initially (P < .02). CONCLUSIONS On the basis of the current best available evidence, the prognosis for endodontic treatment when a fractured instrument fragment is left within a root canal is not significantly reduced.

A Comparative Investigation of Cone-beam Computed Tomography and Periapical Radiography in the Diagnosis of a Healthy Periapex

INTRODUCTION This research aimed to compare the appearance of healthy periapical tissues on cone-beam computed tomography (CBCT) with periapical radiography and to measure the periodontal ligament (PDL) space on CBCT for teeth with healthy and necrotic pulps. METHODS Patient records from specialist endodontic practices were examined for teeth that had a high-resolution (0.08-mm voxel) and small field-of-view CBCT scan, a periapical radiograph, and clinical pulp tests (CO2 and electric pulp testing). The periapical regions of the CBCT scans and radiographs were scored individually by 2 calibrated, blinded examiners by using a modified CBCT-periapical index (CBCT-PAI) for both and represented as CBCT-PAI and PAI, respectively. The Fisher exact and χ(2) statistics tested the relationships between CBCT-PAI, PAI, and pulp status. RESULTS Of 200 teeth included in the study, 166 showed clinical signs of pulpal health, and the CBCT-PAI score was greater than the PAI in 72% (119 of 166), with a vital pulp likely to have a radiographic PDL space widening of 0-1 mm (P < .001). Although 2 healthy teeth showed radiolucencies 2-4 mm on CBCT scan when the periapical radiograph showed none, a PDL space of greater than 1-2 mm was indicative of a necrotic pulp (P < .001). CONCLUSIONS Teeth with necrotic pulps were more likely to have PDL widening, but the PDL space of a healthy tooth demonstrated significant variation when examined by CBCT. The radiographic interpretation of health and disease on CBCT must be further investigated before usage in outcome or epidemiologic investigations. This research questions the traditional radiographic interpretation of the PDL space.

Australian endodontists’ perceptions of single and multiple visit root canal treatment

AIM To ascertain endodontists point of view (treatment philosophy, rationale and preference) regarding single- and multiple-visit root canal treatment. To identify the basis on which the choice is made and how the information necessary for the choice is acquired. METHODOLOGY Endodontists registered with the dental practice board of every state in Australia were contacted, and if they agreed to participate, they were interviewed either face to face or by telephone. The following topics were addressed in an interview lasting 15 to 20 min: demographics, current clinical procedures, treatment rationales and preference. A hypothetical scenario was posed to investigate which treatment regimen they would prefer to deliver if biological concerns were eliminated from consideration. RESULTS Fifty-two endodontists (71% of all Australian endodontists) agreed to participate in the study. Almost all (51/52) participants had performed single-visit root canal treatment, but very few routinely performed it. A majority of participants were willing to provide single-visit treatment where patients had time constraints, and in vital cases (including elective endodontics). The most powerful factor of influencing practice change was interpersonal contact with colleagues. Publications in academic journals have a weak influence in practice change. CONCLUSIONS Australian endodontists strongly prefer multiple-visit over single-visit root canal treatment even in cases where biological concerns are not an issue. Operator preference rather than biological or patient considerations appear to be the primary determinant of treatment choice.

Root canal debridement efficacy of different final irrigation protocols

AIM To compare the smear layer and debris removal effectiveness of four root canal irrigation protocols as well as their effectiveness in removing remaining soft tissues in curved root canals. METHODOLOGY The mesiobuccal and mesial root canals of 107 extracted human maxillary and mandibular molars were instrumented using Mtwo rotary NiTi instruments then randomly divided into four groups according to a final rinse protocol: Group 1 (n = 28) - manual agitation of 1% NaOCl and 15% EDTA; Group 2 (n = 26) - CanalBrush agitation of 1% NaOCl and 15% EDTA; Group 3 (n = 26) - 3% H(2) O(2) alternated with 1% NaOCl; Group 4 (n = 27) - passive ultrasonic agitation of 1% NaOCl and 15% EDTA. All irrigation protocols were performed in a closed system. Eleven roots per group were prepared and histologically stained (H&E) to assess percentage of remaining pulpal tissues in the apical thirds. The remaining specimens were split longitudinally and examined under scanning electron microscope at ×2000 magnification to assess smear layer and debris removal. Image Pro Plus 6.0 software was used to analyse smear layer and remaining pulp tissue. Debris presence was scored by two blinded investigators using a five-point scale. Data were analysed using Univariate analysis of variance (GenStat 13, α = 0.05). RESULTS CanalBrush and passive ultrasonic irrigation were equally effective with significantly less smear layer and debris than manual agitation and H(2) O(2) alternated with NaOCl (P < 0.05). The H(2) O(2) alternated with NaOCl protocol was significantly more effective in removing pulp tissue remnants in the apical level than manual agitation (P = 0.009) and passive ultrasonic irrigation (P = 0.01). CONCLUSIONS CanalBrush was as effective as passive ultrasonic irrigation in smear layer and debris removal. Alternating H(2) O(2) with NaOCl was effective in removing soft tissues from root canal complexities. Further studies are required to evaluate effectiveness of this regimen taking into account irrigant volume differences and effect of root canal system configuration.

Effect of Ultrasonication on Physical Properties of Mineral Trioxide Aggregate

Aim. To evaluate the effect on physical properties of Mineral Trioxide Aggregate (MTA) of using direct hand compaction during placement and when using hand compaction with indirect ultrasonic activation with different application times. Methods. One hundred acrylic canals were obturated in 3 increments with MTA in sample sizes of 10. One group was obturated by hand with an endodontic plugger and the remainder obturated with indirect ultrasonic application, with times ranging from 2 seconds to 18 seconds per increment. Microhardness values, dye penetration depths, and radiographs of the samples were evaluated. Results. As ultrasonic application time per increment increased, microhardness values fell significantly (P < 0.001) while dye penetration values increased (P < 0.001). Microhardness of MTA ultrasonicated for 2 seconds was significantly higher than hand compaction (P = 0.03). Most radiographic voids were visible in the hand-compacted group (P < 0.001), which also had higher dye penetration depths than the 2-second ultrasonicated samples. Ultrasonication of MTA for 10–18 seconds resulted in significantly more voids than 2–8 seconds of ultrasonication (P = 0.02). Conclusion. The use of ultrasonics with MTA improved the compaction and flow of MTA, but excessive ultrasonication adversely affected MTA properties. A time of 2 seconds of ultrasonication per increment presented the best compromise between microhardness values, dye penetration depths, and lack of radiographic voids.

In Vitro Assessment of Mineral Trioxide Aggregate Setting in the Presence of Interstitial Fluid Alone

INTRODUCTION The aim of this study was to determine the ability of white mineral trioxide aggregate (MTA) Angelus (Solucoes Odontologicas, Londrina, Brazil) to set in 24 hours within the root canal in the presence of an intrinsic moisture source (interstitial fluid) alone without the need for moist cotton pellet placement. METHODS Extracted teeth were used to simulate the open apex situation. MTA was placed to a depth of 4 mm and allowed to set for 24 hours in the following test groups: a current protocol group with a moist cotton pellet, a test group with no moist cotton pellet placement, and positive and negative control groups with varnished roots. The teeth were embedded in florist sponges immersed in fetal bovine serum at 13.3-kPa pressure. The MTA set was tested using the Vickers hardness test, and the data were analyzed using analysis of variance. RESULTS The greatest mean surface hardness values were observed in the current protocol group (80.7 ± 35.6), but this was not statistically different when compared with the test group without a moist cotton pellet (78.3 ± 53.7) or the control groups. CONCLUSIONS Moist cotton pellet placement may not be essential for MTA setting in apexification procedures or situations in which the apical surface of the MTA is against a moist opening of greater than 1 mm.

Questions and answers in evidence-based patient care

Evidence-based healthcare has become the mainstream of current healthcare practices, yet there seem to be many misunderstandings concerning this concept. This paper reviews several aspects of the concept of evidence-based healthcare in a simple question-and-answer format. The areas considered include: the significance of the evidence-based concept in clinical practice, the method of conducting a detailed electronic search of the literature, and the interpretation and application of research evidence to patients and immediate clinical applications.