Journal Of Endodontics Research Articles

The efficacy of five techniques for removing root filling material: microscopic versus radiographic evaluation

To test and compare the efficacy of five methods for the removal of root filling material and to test the hypothesis that radiographs fail to represent the real extent of remaining material on canal walls. Fifty maxillary anterior single-rooted teeth with straight root canals were selected. The coronal third of each root canal was prepared with Gates-Glidden drills to number 3, whilst the apical two-thirds were prepared with manual K-files to size 40. Root fillings were performed using lateral compaction with gutta-percha and AH-26. After full setting, the coronal third of the root filling was removed with Gates-Glidden drills and the teeth divided into five groups (n=10). The remaining root filling material was then removed with either Hedström files and chloroform (25 μL), using size 40 as the last file, SafeSider files, using a NiTi Pleezer reamer with a 0.06 taper followed by size 40 reciprocating file, with or without chloroform, or ProTaper Universal retreatment files (D2, D3) with or without chloroform. Reaching working length with no more gutta-percha on the last file was defined as the endpoint for all procedures. The presence of remaining filling material was first evaluated radiographically and then by the microscopic evaluation of split roots. The time required to accomplish the procedure was also recorded. anova and anova with repeated measures were used for statistical analysis of the results. Overall, 11-26% of the canal wall remained covered with filling material; no significant difference was found between the groups. The mechanized methods were faster than manual removal of filling material (P < 0.01); the use of solvent did not speed up the mechanized procedures. Radiographic evaluation failed to adequately and reliably detect the extent of filling material remaining on the canal walls, which was later observed by microscopic evaluation. All methods left root canal filling material on the canal walls. Radiographic evaluation failed to detect the extent of remaining root filling material, which could only be detected using microscopy.

A multiparametric assay to compare the cytotoxicity of endodontic sealers with primary human osteoblasts

To compare the cytotoxicity of four endodontic sealers (Sealapex, Pulp Canal Sealer EWT, Real Seal and MTA Fillapex) either 1 or 7 days after mixing, when assessed through a multiparametric analysis employing human primary cells closely related to periapical tissues. Extracts of each sealer were prepared following 24-h exposure to culture media, at either 24 h or 7 days after mixing. Primary human osteoblasts were exposed to extracts for 24 h, at 37 °C with 5% CO(2) , and cell viability was evaluated by a multiparametric assay assessing sequentially, on the same cells, mitochondrial activity (XTT), membrane integrity (neutral red test) and total cell density (crystal violet dye exclusion test). Results from each test and experimental time were compared by 2-way analysis of variance (anova). All endodontic sealers had strong cytotoxicity 24 h after mixing, according to all parameters evaluated. At a longer setting period (7 days), viability for Sealapex was significantly increased (P < 0.05) and Pulp Canal Sealer achieved levels of cytocompatibility similar to the control group. The anova indicated a general correlation between the cytotoxicity of the materials and the time after mixing, with some level of dependence on the cell viability assay employed. All materials had high cytotoxic levels for human primary cells, mostly on a time-dependent basis, as shown by three different cell viability tests.

Root-filled teeth with adequate restorations and root canal treatment have better treatment outcomes

Medline, Embase, the Cochrane Library, the Wiley online database, four journals (Journal of Endodontics, International Endodontic Journal, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontology and Endodontics and Dental Traumatology) and the references of identified articles were searched manually. There was no language restriction. Clinical studies that provided sample size, and where success was based on radiographic and/or clinical criteria that evaluated quality of root filling, the quality of coronal restoration and periapical status at least one year after root canal treatment that provided an overall success rate or sufficient data to allow it to be calculated from the raw data were included. Data were collected based on predetermined criteria. Percentages of teeth without apical periodontitis were recorded for each category: adequate root canal treatment (AE); inadequate root canal treatment (IE); adequate restoration (AR); and inadequate restoration (IR). Data were analysed using meta-analysis for odds ratios (ORs). Nine article were included . After adjusting for significant covariates to reduce heterogeneity, the results were combined to obtain pooled estimates of the common OR for the comparison of AR/AE versus AR/IE:-AR/AE versus AR/IE (OR = 2.734; 95%CI, 2.61-2.88; P < .001)AR/AE versus IR/AE (OR = 2.808; 95% CI, 2.64-2.97; P < .001). On the basis of the current best available evidence, the odds for healing of apical periodontitis increase with both adequate root canal treatment and adequate restorative treatment. Although poorer clinical outcomes may be expected with adequate root filling-inadequate coronal restoration and inadequate root filling-adequate coronal restoration, there is no significant difference in the odds of healing between these two combinations.

Preliminary evaluation of a novel polymer nanocomposite as a root-end filling material

To evaluate two nanoparticle-enhanced polymer root-end filling materials (NERP1 and NERP2) on the initial apical seal as compared to a polymer-based commercial compomer. One hundred and forty extracted roots with completely formed apices were resected 3 mm from the apex. Cavities were then prepared in the apical openings of the resected root ends using an ultrasonic handpiece to a depth of 3 mm. The roots were then randomly divided into five groups to receive one of five root-end filling materials. Roots in groups 1 and 2 received NERP1 and NERP2, whilst those in groups 3 and 4 received identical polymers as groups 1 and 2 but without nanoparticle addition (RP1 and RP2, respectively). The root-end cavities for the fifth group were filled with commercially available root-end filling compomer. Roots were mounted in a dual-chamber leakage apparatus and inoculated coronally with Enterococcus faecalis. Turbidity of the apical broth was assessed daily for 4 weeks as a sign of initial leakage. The results were statistically analysed using odds ratio and Fisher's chi-square analysis. Nanoparticle-enhanced root-end filling polymer 1 displayed significantly fewer leaked samples compared to all other tested groups as early as 5 days, whilst NERP2 was not significantly different compared to other groups. Odds ratio analysis revealed leakage of the commercial compomer was 12 times more likely than NERP1. Nanoparticle-enhanced root-end filling polymer 1 can reduce apical microleakage significantly under laboratory conditions.

Fluoride-containing nanoporous calcium-silicate MTA cements for endodontics and oral surgery: early fluorapatite formation in a phosphate-containing solution

To test the chemical-physical properties and apatite-forming ability of experimental fluoride-doped calcium silicate cements designed to create novel bioactive materials for use in endodontics and oral surgery. A thermally treated calcium silicate cement (wTC) containing CaCl(2) 5%wt was modified by adding NaF 1%wt (FTC) or 10%wt (F10TC). Cements were analysed by environmental scanning electron microscopy with energy-dispersive X-ray analysis, IR and micro-Raman spectroscopy in wet conditions immediately after preparation or after ageing in a phosphate-containing solution (Dulbecco's phosphate-buffered saline). Calcium and fluoride release and pH of the storage solution were measured. The results obtained were analysed statistically (Tukey's HSD test and two-way anova). The formation of calcium phosphate precipitates (spherulites) was observed on the surface of 24 h-aged cements and the formation of a thick bone-like B-type carbonated apatite layer (biocoating) on 28 day-aged cements. The rate of apatite formation was FTC>F10TC>wTC. Fluorapatite was detected on FTC and F10TC after 1 day of ageing, with a higher fluoride content on F10TC. All the cements released calcium ions. At 5 and 24 h, the wTC had the significantly highest calcium release (P<0.001) that decreased significantly over the storage time. At 3-28 days, FTC and F10TC had significantly higher calcium release than wTC (P<0.05). The F10TC had the significantly highest fluoride release at all times (P<0.01) that decreased significantly over storage time. No significant differences were observed between FTC and wTC. All the cements had a strong alkalinizing activity (OH(-) release) that remained after 28 days of storage. The addition of sodium fluoride accelerated apatite formation on calcium silicate cements. Fluoride-doped calcium silicate cements had higher bioactivity and earlier formation of fluorapatite. Sodium fluoride may be introduced in the formulation of mineral trioxide aggregate cements to enhance their biological behaviour. F-doped calcium silicate cements are promising bone cements for clinical endodontic use.

Generalized pulp stones: report of a case with 6-year follow-up

To present a mildly mentally retarded patient with generalized pulp stone formation and the six-year follow-up and to discuss the differential diagnosis of the case. Pulp stones were radiographically detected in the pulp chamber of all permanent teeth in a 25-year-old woman with mild mental retardation who presented for endodontic treatment on tooth no 11 (FDI). The patient's medical, dental and family history was noncontributory. The pulp stone in the pulp chamber of tooth no 11 was removed during canal filing, and root canal treatment completed uneventfully. Six years later, the patient was re-evaluated and the pulp stones were unchanged radiographically. The patient's family history, facial phenotype and karyotype as well as the radiographic, laboratory and physical examination were not consistent with any of the known genetic syndromes associated with generalized pulp stones. Molecular analysis for the DSPP gene proved negative. The aetiology of this case remains unknown. Generalized pulp stones occur rarely; Such patients should be referred for genetic evaluation because pulp stones are mostly associated with genetic dentine defects; Pulp stones may hinder root canal treatment; Pulp stones may remain unchanged overtime.

Managing severe curvature of radix entomolaris: three-dimensional analysis with cone beam computed tomography

To present a case of a mandibular first molar with an additional distolingual root [radix entomolaris (RE)] and to discuss the use of cone beam computed tomography (CBCT) for its identification and management during root canal treatment. A 52-year-old Caucasian woman was referred for root canal treatment of the right mandibular first molar (tooth 46). After clinical and radiographic examination, a symptomatic irreversible pulpitis was diagnosed. Three periapical radiographs with different horizontal angulations revealed the presence of an additional distolingual root. This extra root, termed RE, has an incidence of <5% in the Caucasian population. A CBCT examination was also taken, which revealed a severe root canal curvature, especially in the middle third, of this supernumerary root. CBCT provided more accurate information in terms of RE inclination and root canal curvature before commencing root canal treatment. The conventional access opening was modified into a more trapezoidal cavity, and five root canals were found. All canals were instrumented with new nickel-titanium (NiTi) files to reduce the risk of fractured instruments. After preparation, the root canals were filled using thermoplastified techniques. The 1-year follow-up periapical radiographs and CBCT images revealed a continuous periodontal space with no signs of apical periodontitis. • Cone beam computed tomography imaging is useful in identifying the root canal system and the surrounding structures. • An accurate detection of supernumerary roots, such as RE, can avoid complications during and after root canal treatment. • The analysis of root canal curvature is important because instrument fracture has been linked to angle and radius of curvature. • The use of new instruments can reduce the incidence of instrument fracture.

Failure analysis and survival rate of post and core restorations under cyclic loading

To investigate in a laboratory setting the influence of (i) post material (ii) preparation design and (iii) luting agent on the survival probability of root filled teeth, restored with all-ceramic restorations. The crowns of 80 extracted single-rooted human teeth were removed, and root canal treatment was performed including canal filling with Gutta-percha without sealer (crown-down-pressureless technique). The root fillings were removed and the root canal enlarged with a reamer up to size 110. Prefabricated zirconia (CeraPost) or glass-fibre-reinforced posts (DentinPost) were luted using either Ketac Cem or Panavia F 2.0. A core build-up was applied (Clearfil Photocore), and the teeth were prepared with or without a 2-mm ferrule design (n=10 per experimental group). The prepared teeth were scanned (Cerec 3D) and crowns fabricated. After luting of the crowns (Ketac Cem), teeth were subjected to thermocycling (×4000, 5-55 °C) and cyclic loading (1.5 million cycles, 90 N). After load cycling, the teeth were immersed in methyleneblue solution for 24 h and subsequently sectioned in three segments for a dye penetration test. Kaplan-Meyer analysis was performed to assess the survival probability followed by a Cox regression analysis (α=5%). Teeth prepared using the ferrule design as well as the teeth with DentinPosts exhibited a significantly higher survival probability (P<0.05). The luting agent was of minor importance (P>0.05). Most common failure was debonding of posts (CeraPost) and post fracture (DentinPost). The majority of the teeth showed dye penetration after cyclic loading. Post material and ferrule design were of paramount importance regarding the survival probability of the post and core restorations using pre-fabricated posts. DentinPosts showed superior results versus CeraPosts.

Pulp pathosis in inlayed teeth of the ancient Mayas: a microcomputed tomography study

To evaluate three-dimensionally, using microcomputed tomography (μCT), the anatomical relationship between the cavity prepared to hold the inlay stone and the pulp chamber in the teeth of the ancient Maya. Six well-preserved teeth from Maya corpses found in an archaeological site in Guatemala (approximately 1600 year old) were selected and scanned using a high-resolution μCT system (SkyScan 1174v2; SkyScan N.V., Kontich, Belgium). The sample comprised six maxillary teeth: two canines, one premolar, two central incisors and one lateral incisor. All teeth had one or two inlay stones on the buccal surface of the crown. Each specimen was scanned at an isotropic resolution of 22.5 μm, a rotational step of 0.70°, a rotational angle of 180° and a 3.1-s exposure time, using a 1-mm-thick aluminium filter. Images of each specimen were reconstructed from apex to the crown with dedicated software (NRecon v1.6.1.5) in approximately 450 slices. CTan v1.11 and CTVol v2.1 were used for three-dimensional visualization and qualitative analysis of the external and internal anatomy of the teeth. The tooth modification in all samples was classified as type E1 (one stone on the buccal surface of the crown) or E2 (two stones on the buccal surface of the crown). In the canine teeth, the cavities created to insert the inlay stone did not reach the pulp chamber. Conversely, in the maxillary incisors, the cavities clearly perforated the pulp chamber resulting in massive internal inflammatory resorption or partial calcification of the pulp cavity. In the premolar tooth, a small perforation of the pulp chamber under the buccal cusp, without morphological alteration of the intraradicular dentine, was observed. Microcomputed tomography analysis of teeth of the ancient Maya civilization showed that the inlay cavities cut reached the pulp chamber in the maxillary incisors and premolar teeth, with the potential to cause pulp and periapical disease.

Autotransplantation of a maxillary first premolar to replace an ankylosed maxillary incisor: 7-year follow-up

To present the combined endodontic, surgical and orthodontic treatment of an autotransplanted maxillary first premolar for the replacement of an ankylosed maxillary incisor. This case report describes the autotransplantation of a maxillary premolar after the extraction of an ankylosed incisor in a 13-year-old boy. To allow better adaptation of the donor tooth, the buccal root of the first premolar was removed using a diamond bur and the denuded root site was filled with acid-etched composite resin. The palatal root canal was dressed with calcium hydroxide for 2 months before filling with gutta-percha. Autotransplantation of a remodelled maxillary first premolar was achieved to substitute for the ankylosed maxillary central incisor. Orthodontic treatment was performed to correct an Angle Class II malocclusion. Seven years after root canal treatment, the autotransplanted tooth and supporting tissues appeared healthy both clinically and radiographically and were functioning well. • Autotransplantation is a viable option for the treatment of a missing tooth or for the replacement of a traumatized tooth when there is a donor tooth available. • Autotransplantation of a premolar for replacement of a missing anterior tooth is sometimes a suitable alternative to conventional prosthetic rehabilitation or implant treatment in young individuals. • Proper combined endodontic and orthodontic treatment of autotransplanted teeth might be possible without periodontal complications.

Reporting of Research Quality Characteristics of Studies Published in 6 Major Clinical Dental Specialty Journals

The objective of this article was to record reporting characteristics related to study quality of research published in major specialty dental journals with the highest impact factor (Journal of Endodontics, Journal of Oral and Maxillofacial Surgery, American Journal of Orthodontics and Dentofacial Orthopedics; Pediatric Dentistry, Journal of Clinical Periodontology, and International Journal of Prosthetic Dentistry). The included articles were classified into the following 3 broad subject categories: (1) cross-sectional (snap-shot), (2) observational, and (3) interventional. Multinomial logistic regression was conducted for effect estimation using the journal as the response and randomization, sample calculation, confounding discussed, multivariate analysis, effect measurement, and confidence intervals as the explanatory variables. The results showed that cross-sectional studies were the dominant design (55%), whereas observational investigations accounted for 13%, and interventions/clinical trials for 32%. Reporting on quality characteristics was low for all variables: random allocation (15%), sample size calculation (7%), confounding issues/possible confounders (38%), effect measurements (16%), and multivariate analysis (21%). Eighty-four percent of the published articles reported a statistically significant main finding and only 13% presented confidence intervals. The Journal of Clinical Periodontology showed the highest probability of including quality characteristics in reporting results among all dental journals.

Genotoxicity evaluation of dentine bonding agents by comet assay

To evaluate the genotoxicity of four different adhesives, Clearfil SE Bond, SL Bond, i Bond and Clearfil Protect Bond and the primers of Clearfil SE Bond and Clearfil Protect Bond. Genotoxicity assessment of the adhesives and primers was carried out in vitro in human lymphocytes at different elution concentrations, using the alkaline single-cell gel electrophoresis technique (comet assay). After the incubation of lymphocytes with varying volumes of the test agent, cells were embedded in a low-melting-point agarose suspension and then lysed in alkaline (pH>13) conditions. Electrophoresis was performed on the suspended lysed cells followed by visual analysis with staining of DNA. Fluorescence was than calculated to determine the extent of DNA damage using imaging software. Statistical comparison of the results was carried out by one-way analysis of variance (anova). A significant increase (P<0.001) compared to untreated controls in DNA damage was observed with 'Clearfil Protect Bond' and 'Clearfil SE Bond' primer in human lymphocytes at concentrations of 2.5 and 5.0 mg mL(-1). Clearfil Protect Bond and Clearfil SE Bond adhesives induced significant (P < 0.001) DNA damage only at the higher concentration of 5.0 mg mL(-1) . No significant increase in DNA damage was observed with SL Bond and i Bond. No significant DNA damage was observed with any dentine bonding agents at the lower concentration of 1.25 mg mL(-1) . 'Clearfil Protect Bond' and 'Clearfil SE Bond' primers/adhesives increased DNA damage in human peripheral lymphocytes in high doses.

Comparison of ropivacaine and articaine with epinephrine for infiltration anaesthesia in dentistry - a randomized study

To compare the efficacy, onset time and duration of maxillary infiltration anaesthesia with 0.5% plain ropivacaine or 4% articaine with epinephrine 1 : 100 000 and to determine their possible influence on cardiovascular parameters. Sixty volunteers received 1.8 mL of the anaesthetic for buccal infiltration anaesthesia of maxillary central and lateral incisors and canine teeth without caries, restorations or signs of pulpitis. The efficacy, onset time and duration of pulp anaesthesia were assessed with an electric pulp tester. The duration of numbness of the upper lip was also monitored. Blood pressure and heart rate were measured before and after administration of the solutions. The efficacy of anaesthesia of lateral and central incisors was 100% for both anaesthetics. There were insignificant differences in effectiveness of canine pulp anaesthesia. The mean onset time was significantly (P < 0.05) shorter for ropivacaine (2.22 min) when compared with articaine (4.08 min). The duration of action and soft tissue anaesthesia were also significantly (P < 0.05) longer for ropivacaine (79.2 and 264 min) when compared with articaine (63.7 and 195.2 min, respectively). Ropivacaine caused significant (P < 0.05) increases in blood pressure and heart rate. Ropivacaine (0.5%) achieved effective and long duration of uninflamed pulp and soft tissue anaesthesia. Ropivacaine could be useful for long-lasting operative procedures without the need for a vasoconstrictor.

Ex vivo detection of mesiobuccal canals in maxillary molars using CBCT at four different isotropic voxel dimensions

To study observers' ability to detect mesiobuccal (MB) canals in maxillary molars using iCAT cone-beam computed tomography (CBCT) at different voxel dimensions and to assess the impact of clinical experience on accuracy of detection. Using 12 experimental models with two molars each, CBCT scans were acquired at four different voxel dimensions. From the cross-section view of these scans, 96 videos were generated. Five endodontic postgraduate students and two endodontic staff watched the videos and counted the MB canals in each root. Horizontal sections of the roots were evaluated under magnification to determine the true canal numbers. The detection of MB canals within the four resolutions was compared by odds ratio, and the weighted χ(2) test compared detection accuracy to raters' clinical experience. Rater agreement was measured by kappa statistics. Overall, 92% of the maxillary molars had two MB canals upon analysis of horizontal cross-sections. The CBCT detection increased from 60.1% at 0.4 mm voxel size to 93.3% at 0.125 mm voxel size. Significant differences (P < 0.01) were observed between the different resolutions except for the 0.2 and the 0.125 voxel scans. Second-year trainees were significantly (CI = 0.2929-0.712) more accurate than first-year trainees and endodontic staff at MB canal detection (87.9% against 77.1% and 76.8%). Intra-rater reliability increased with higher-resolution scans (41.1% to 96.4%). The reliability of detection of maxillary molar MB2 canals in CBCT scans increased as the resolution improved. Accuracy of MB2 canal detection among observer groups could not be correlated with the observers' level of clinical experience.

Expression of MMP-8 and MMP-13 in the development of periradicular lesions

To elucidate the expressions of MMP-8 and MMP-13 in experimentally induced rat periradicular lesions by means of the reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical staining. Thirty rats were used and periradicular lesions in mandibular first molar teeth were established following pulp exposure. The animals were sacrificed at 0 (no exposure control), 1, 2, 3, 4 and 6 weeks after pulp exposure. The right molars were used for RT-PCR analysis of MMP-8 and MMP-13. The left molars were subjected to immunohistochemical staining with both MMPs. The areas of these lesions were measured histometrically, and the numbers of both reactive cells in the periapical portion were counted per unit area. Significant differences were analysed by the Mann-Whitney U-test. MMP-8 gene expression gradually increased from 2 to 4 weeks, but slightly decreased at 6 weeks. MMP-13 gene expression gradually increased from 1 to 3 weeks. At 4 and 6 weeks, the level of expression was as high as that at 3 weeks. Immunohistochemically, MMP-8 was first detected at 2 weeks and gradually increased until 4 weeks. MMP-13 gradually increased from 1 to 4 weeks. Both MMPs decreased at 6 weeks. The area of the periradicular lesions gradually increased from 1 to 4 weeks, showing a large increase in week 2 and 3 in particular, but then decreased in week 6. MMP-13-expressing cells were significantly greater than MMP-8-positive cells at week 1 and 2. These findings indicate that MMP-8 and MMP-13 were related to the development of periradicular lesions. It is suggested that MMP-13 increased from an early stage during their development and that MMP-8 is involved in the progression of tissue destruction including bone resorption.

Flexibility and torsional resistance of three nickel-titanium retreatment instrument systems

To assess the dimensional characteristics, flexibility and torsional behaviour of nickel-titanium retreatment instruments. Using image analysis software and high-resolution digital images, the instrument length, tip angle, diameter at 3 mm from the tip and the distance between the blades (pitch length) of the following eight instruments were measured (n = 12 for each measurement parameter): the ProTaper Universal retreatment (PTU-R) D1, D2 and D3 instruments; the R-Endo R1, R2 and R3 retreatment instruments; and the Mtwo retreatment (Mtwo-R) sizes 25 and 15 retreatment instruments. Maximum torque and the angular deflection at fracture as well as the bending moment at 45° were measured (n = 12) according to the International Standards Organisation (ISO) specification number 3630-1. Data were analysed using the analysis of variance (α = 0.05). The length of the active part of the instruments was found to vary according to the depth of the canal into which they were designed to reach. The pitch length also increased along the active length. The PTU-R D1 and the Mtwo-R instruments had active tips. Measurements of the bending moment at 45° revealed that the Mtwo-R 15 instrument was the most flexible, whereas the PTU-R D1 was the least flexible. The maximum torque tended to increase as the instrument diameter at 3 mm from the tip increased, whereas the angular deflection at fracture varied in the opposite direction. The geometrical characteristics of the retreatment instruments and their flexibility and torsion behaviour were consistent with their intended clinical application.

Comparison of the root-end seal provided by bioceramic repair cements and White MTA

To compare the ability of Ceramicrete, BioAggregate and white ProRoot MTA (mineral trioxide aggregate) to prevent glucose leakage through root-end fillings. After root canal instrumentation, the apical 3 mm of maxillary incisors were resected and retropreparations, 3 mm in depth, were created with ultrasound. Root-end cavities were filled with the tested materials (15 roots per group). All roots were mounted in a double-chamber system to assess glucose penetration using 15 psi pressure application. After 1 h, glucose concentrations in the lower chamber were measured following an enzymatic reaction. Four roots were used as controls. One-way anova verified differences in glucose leakage between groups and Tukey test performed multiple comparisons. Significance was set at α = 5%. There was a significant difference between the three materials (anova, P < 0.05). Ceramicrete had significantly lower glucose penetration than BioAggregate (Tukey, P < 0.05). There was no difference between the two bioceramic cements and white MTA (P > 0.05). Both endodontic bioceramic repair cements displayed similar leakage results to white MTA when used as root-end fillings materials. Ceramicrete had significantly lower glucose penetration.

A prospective study of the factors affecting outcomes of non-surgical root canal treatment: part 2: tooth survival

To investigate the probability of and factors influencing tooth survival following primary (1°RCTx) or secondary (2°RCTx) root canal treatment. This prospective study involved annual follow-up of 2 (100%) to 4 years (50%) of 1°RCTx (759 teeth, 572 patients) and 2°RCTx (858 teeth, 642 patients) carried out by Endodontic postgraduate students. Pre-, intra- and post-operative data were collected prospectively from consented patients. Information about extraction of the root filled tooth was sought from the patient, the referring dentist or derived from the patient's records and included the timing and reasons for extraction. Tooth survival was estimated and prognostic factors were investigated using Cox regression. Clustering effects within patients were adjusted in all models using robust standard error. The 4-year cumulative tooth survival following 1°RCTx [95.4% (93.6%, 96.8%)] or 2°RCTx [95.3% (93.6%, 96.5%)] was similar. Thirteen prognostic factors were identified. Significant patient factors included history of diabetes and systemic steroid therapy. Significant pre-operative factors included narrow but deep periodontal probing depth; pain; discharging sinus; and iatrogenic perforation (for 2°RCTx cases only). Significant intra-operative factors included iatrogenic perforation; patency at apical terminus; and extrusion of root fillings. Significant post-operative restorative factors included presence of cast restoration versus temporary restoration; presence of cast post and core; proximal contacts with both mesial and distal adjacent teeth; and terminal location of the tooth. The presence of pre-operative pain had a profound effect on tooth loss within the first 22 months after treatment [hazard ratio (HR) = 3.1; P = 0.001] with a lesser effect beyond 22 months (HR = 2.4; P = 0.01). Patency at the apical terminus reduced tooth loss (HR = 0.3; P < 0.01) within the first 22 months after treatment but had no significant effect on tooth survival beyond 22 months. Extrusion of gutta-percha root filling did not have any effect on tooth survival (HR = 1.1; P = 0.2) within the first 22 months but significantly increased the hazard of tooth loss beyond 22 months (HR = 3.0; P = 0.003). The 4-year tooth survival following primary or secondary root canal treatment was 95%, with thirteen prognostic factors common to both.

Endodontic surgery prognostic factors

Medline, (PubMed) and the Cochrane databases together with hand searching of the following journals: Journal of Endodontics, International Endodontic Journal, Oral Surgery Oral Medicine Oral Pathology (name changed to Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics in 1995), Endodontics and Dental Traumatology (name changed to Dental Traumatology in 2001), Journal of Oral and Maxillofacial Surgery, and International Journal of Oral and Maxillofacial Surgery. Clinical studies evaluating apical surgery with placement of a root-end filling were included. Studies on apical surgery with orthograde root canal filling or about apicectomy alone without root-end filling were excluded, as were experimental and animal studies. Only studies with ≥ ten patients with a minimum six month follow-up period and clearly defined radiographic and clinical healing criteria, with healing reported for at least two categories of a specific prognostic factor were accepted. Studies reporting in English, German, French, Spanish, Italian, Portuguese and Scandinavian languages were included. All studies were assessed separately by two of the three authors, with disagreements resolved by discussion. Prognostic factors were divided into patient related, tooth-related or treatment-related factors. The reported percentages of healed teeth were pooled per category. The statistical method of Mantel-Haenszel was applied to estimate the odds ratios and their 95% confidence intervals. Homogeneity was assessed using Woolf's test. With regard to tooth-related factors, the following were identified as predictors of healing: absence of preoperative pain or signs, good density of the root canal filling and a periapical lesion size of ≤ 5 mm. With regard to treatment-related factors, teeth treated with the use of an endoscope tended to have higher healed rates than teeth treated without the use of an endoscope. Although the clinician may be able to control treatment-related factors (by choosing a certain technique), patient- and tooth-related factors are usually beyond the surgeon's power. Nevertheless, patient and tooth-related factors should be considered as important prognostic determinants when planning or weighing apical surgery against treatment alternatives.

Tooth survival after root canal treatment

Medline, the Cochrane Library, hand searches of the International Endodontic Journal, Journal of Endodontics, Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics, Dental Traumatology (& Endodontics) and bibliographies of all relevant articles and review articles. Unpublished studies were identified by searching abstracts and conference proceedings. Personal contacts were used to identify ongoing or unpublished studies. Two reviewers independently assessed and selected the studies with disagreements being resolved by discussion. Clinical studies of RCTx on more than 30 teeth and of at least six-month duration, where the success was based on survival of tooth and the proportion of teeth surviving was given, or could be calculated from the raw data, were included. Data were extracted by two reviewers independently using custom-designed forms. The weighted pooled proportion of teeth surviving after treatment and the combined effects (expressed as odds ratio) of clinical factors on tooth survival were estimated using fixed and random effects meta-analyses using DerSimonean and Laird's methods. The survival data were pooled into three groups based on the duration after treatment: 2 or 3 years; 4 or 5 years; and 8, 9 or 10 years. Statistical heterogeneity amongst the studies was assessed by Cochran's (Q) test. Of the 31 articles identified, 14 studies were included. The majority (10) were retrospective. The reported survival is shown in Table 1. Substantial differences in study characteristics were found to hinder effective direct comparison of findings. Evidence for the effect of prognostic factors on tooth survival was weak. Based on the data available for meta-analysis, four conditions were found to significantly improve tooth survival. In descending order of influence, the conditions increasing observed proportion of survival were as follows: (i) a crown restoration after RCTx; (ii) tooth having both mesial and distal proximal contacts; (iii) tooth not functioning as an abutment for removable or fixed prosthesis; and (iv) tooth type or specifically non-molar teeth. Statistical heterogeneity was substantial in some cases, but its source could not be investigated because of insufficient available information. The pooled proportion of teeth surviving over 2-10 years following RCTx ranged between 86% and 93%. Four factors (listed above) were identified as significant prognostic factors with concurrence between all three strands of evidence.