Incidence and contributing factors of non-root canal treated teeth with chronic fatigue root fracture: A cross-sectional study.

BACKGROUND/PURPOSE: Chronic fatigue root fracture describes a root fracture in a non-root canal treated (non-RCT) tooth. This study aimed to report the incidence and contributing factors of non-RCT teeth with chronic fatigue root fracture in a Taiwanese population. METHODS: This cross-sectional study included teeth extracted at Taipei Veterans General Hospital in Taiwan between 2018 and 2019. The reasons for extractions were recorded and included vertical and horizontal root fractures (VRF and HRF). Comparisons of clinical factors between teeth with fatigue VRF and teeth with fatigue HRF were performed by chi-square or Fisher exact test, where appropriate. RESULTS: Of the 4207 extracted teeth examined, 263 (6.25%) had tooth fracture. Thirty-two non-RCT teeth had chronic fatigue root fracture, including 16 with VRF and 16 with HRF. The incidence was 0.76% (32/4207). The occurrence of chronic fatigue root fracture was higher in males (83.9%). The mean age of the 31 patients with chronic fatigue root fracture was 71.7 ± 13.1 years. More than half of these teeth had intact crowns with severe attrition. The fatigue VRF occurred more frequently in molars (P = 0.003), in roots with a long oval cross-section (P = 0.037), and in terminal teeth (P = 0.013) than the fatigue HRF. CONCLUSION: The incidence of chronic fatigue root fracture is 0.76%. Both VRF and HRF occur mainly in aged males, in posterior teeth with attrition, and in teeth without restoration. Tooth position, cross-section root morphology, and terminal tooth are contributing factors related to chronic fatigue root fracture.

Accreditation of postgraduate speciality training programmes in Endodontology. Minimum criteria for training Specialists in Endodontology within Europe.

This consensus statement from the European Society of Endodontology (ESE) sets out the minimum criteria for training Specialists in Endodontology within Europe. The case is made for recognizing Endodontology as a distinctive dental discipline throughout Europe. Guidelines are presented on the requirements of a specialist and of a specialist training programme in Endodontology. The aims, objectives and curriculum content of a specialist training pathway are outlined, with guidelines on trainee appraisal, and the expectations of faculty and institutional commitment. In publishing these guidelines, the ESE is responding to a public and professional need for consistently high standards of training and specialist clinical service within Europe.

Vertical Root Fracture in Buccal Roots of Bifurcated Maxillary Premolars from Condensation of Gutta-percha.

INTRODUCTION: Maxillary premolars are among the teeth most susceptible to vertical root fracture (VRF) from lateral condensation of gutta-percha. These teeth are distinguished by a complex anatomy of the buccal root including a large depression in the dentin wall facing the bifurcation. It is hypothesized that tooth sectioning coupled with 2-dimensional fracture analysis is instrumental in understanding VRF in such teeth. VRF was examined by tooth sectioning following the development of a fracture mechanics analysis to predict VRF in such roots. METHODS: The fracture morphology in teeth extracted from patients because of VRFs was examined from a series of horizontal cross sections. 2-dimensional fracture mechanics analysis in conjunction with the finite element technique was developed to evaluate VRF caused by canal pressure (q). As in our previous single-rooted tooth model, the apical obturation force (F) was related to q using a simple formula. RESULTS: Fracture was mostly limited to the buccal root, exhibiting some competing modes including fracture from the depression peak to the canal surface and the canal surface to the root surface, which may occur either along straight lines or curved trajectories resembling the depression outline. The analysis predicted clinical fractures well, yielding VRF force values in the upper range used by clinicians during lateral condensation of gutta-percha. CONCLUSIONS: The main etiology for VRF is stress concentration resulting from the combined effect of wedgelike canal depression and the flexibility of periodontal ligament tissue joining the root and bone. This drawback can be alleviated by minimizing canal enlargement and apical condensation force during root canal therapy.

Residual dentin thickness in bifurcated maxillary premolars after root canal and dowel space preparation.

Residual dentin thickness in 25 extracted bifurcated maxillary premolars after canal and Parapost preparation was assessed using acrylic muffle, after embedding in polyester resin and sectioned horizontally. After each procedure, the residual dentin thickness was compared to the original dentin thickness at eight aspects in three root levels. Residual dentin thickness measurements were calculated using photographs and a Digitizer. In the lingual aspect, the original dentin thickness averaged 0.99 mm (coronal slice) and 0.78 mm (middle slice). Dentin removal after dowel preparation was 31%. Three-way ANOVA with repeated measures was used. The difference in residual dentin thickness was highly significant regarding procedure (canal and dowel preparation, p < 0.0001), slice (middle, coronal, p < 0.0001), and the eight aspects (p < 0.0001). This in vitro study emphasizes the minimal dentin width of the buccal root, especially towards the bifurcation. Thus, dowels should be avoided in this root.

Implant-associated Vertical Root Fracture in Adjacent Endodontically Treated Teeth: A Case Series and Systematic Review.

INTRODUCTION: This study aimed to report a possible effect of the presence of an adjacent implant on the development of a vertical root fracture (VRF) in endodontically treated teeth. METHODS: A series of 8 cases in 7 patients with teeth diagnosed with VRF after the placement of implants in the adjacent area is described and analyzed. In addition, a comprehensive literature search with strict inclusion and exclusion criteria was undertaken to identify additional clinical studies that assessed this clinical scenario. RESULTS: The case series analysis revealed that the time from implant placement to the diagnosis of VRF was between 5 and 28 months (average = 11 months). The majority of cases occurred in female patients who received 2 or more implants. Six of the 7 patients were older than 40 years, with an average age of 54 years. The majority of teeth with VRF were premolar or mandibular molar teeth (6/8 teeth). All fractured teeth had been restored with a crown and had a post present, and the quality of the root canal filling was determined to be adequate. The systematic review revealed that implant-associated VRF has not been investigated or reported in the literature yet. CONCLUSIONS: Based on a systematic review of the literature, this case series, although limited in its extent, is the first clinical report of a possible serious adverse event of implant-associated VRF in adjacent endodontically treated teeth. Additional clinical studies are indicated to shed light on this potential phenomenon.

The Effect of Isthmus on Vertical Root Fracture in Endodontically Treated Teeth.

INTRODUCTION: Vertical root fracture (VRF) from apical condensation of gutta-percha is a common failure mode in endodontically treated teeth. Virtually all previous studies of VRF are limited to 1-canal roots. In this study, we consider experimentally and analytically VRF in roots with 2 canals. METHODS: The interior root morphology in mandibular molar teeth extracted from patients due to VRF or other reason was examined from a series of polished horizontal cross sections. A 2-dimensional fracture mechanics analysis was used to determine crack growth from the canal surface to the outer root surface and evaluate the apical load needed to cause VRF, Fmax. RESULTS: From a mechanistic viewpoint, the isthmus connecting root canals can be regarded as a natural weak plane or crack. The results expose the prime role of isthmus in reducing Fmax, from ≈ 50 N with no isthmus present to ≈ 10 N. CONCLUSIONS: Two-canal mesial roots are much more prone to VRF than 1-canal distal roots. We suggest that VRF may occur during clinical condensation of gutta-percha in mesial roots of mandibular molars as well as other roots with canals connected by isthmus.

Comparison of procedural errors resulting during root canal preparations completed by senior dental students in patients using an '8-step method' versus 'serial step-back technique'.

OBJECTIVE: To compare procedural errors that occur in patients during root canal preparation by senior dental students using a new '8-step method' versus the traditional 'serial step-back technique.' STUDY DESIGN: Senior dental students treated 221 root canals of maxillary and mandibular teeth. Instrumentation included coronal flaring with Gates-Glidden reamers and standardized stainless steel K-files in all teeth. A new 8-step method was used to prepare 67 canals using standardized stainless steel hand instruments (8-step SS) and 69 canals using the rotary Nickel Titanium instruments (8-step NiTi). The traditional serial step-back technique (step-back) was used for 85 root canals. In the apical third, reaming or filing motions were used up to sizes 25 and only reaming motion in sizes larger than 25 with the new 8-step method. A filing motion was used in the step-back for all sizes. Root canals of all groups were obturated with gutta-percha points and AH26 using a lateral condensation technique. Pre- and postoperative radiographs were taken of each tooth. Procedural errors were recorded and statistically analyzed using a binomic test for comparison of proportion. RESULTS: Procedural errors detected consisted of 2 canals with transportation (3%) with the 8-step SS, and 3 canals (4%) with transportation with 8-step NiTi. There were no canal obstructions or instrument separations. With the step-back, 20 canals were transported (24%), 7 canals had obstructions (8%), and in 1 canal instrument was separated (1%). CONCLUSIONS: The new 8-step method resulted in fewer procedural errors than the traditional serial step-back technique when senior students prepared root canals in patients either by hand with standardized K-files or by rotary NiTi instrumentation.

Residual dentin thickness in mesial roots of mandibular molars prepared with Lightspeed rotary instruments and Gates-Glidden reamers.

OBJECTIVE: We sought to measure the residual dentin thickness (RDT) in the mesial roots of mandibular molars after instrumentation with Lightspeed and Gates-Glidden rotary instruments. Study design Thirty extracted, untreated human mesial roots of mandibular molars were separated from the distal roots and embedded in clear polyester resin. The roots were cut horizontally at 1, 4, and 7 mm short of the anatomic apex. The diameter of each mesiobuccal canal was measured by using a stereo measuring microscope at each level in the buccolingual and mesiodistal directions. The dentin thickness was measured in each level in the mesial, distal, buccal, and lingual directions. Sections were reassembled with a muffle. The canals were enlarged to the working length with Lightspeed rotary instruments, of which the average size used was a No. 50 file. The coronal third was flared with No. 2 Gates-Glidden reamers. Slices were separated again, and the RDT and canal diameters were measured. RESULTS: The minimal measured RDT after instrumentation at the 1-, 4-, and 7-mm levels was 0.70 +/- 0.28 mm, 1.04 +/- 0.18 mm, and 1.09 +/- 0.19 mm, respectively. The average diameter of the canals after instrumentation at the 1-, 4-, and 7-mm levels was 0.50 +/- 0.04 mm, 0.52 +/- 0.05 mm, and 0.74 +/- 0.08 mm, respectively. The canal diameter did not exceed one third of the root diameter at all levels. CONCLUSIONS: Root canal preparation of mandibular mesial roots with Lightspeed instruments to No. 50 in the apical third and Gates-Glidden reamers to No. 2 in the coronal third does not significantly decrease the RDT.

Cone beam computed tomography for the diagnosis of vertical root fractures: a systematic review of the literature and meta-analysis.

OBJECTIVE: The aim of this review was to compare the efficiency of cone beam computed tomography (CBCT) and conventional intraoral radiography for the detection of vertical root fractures (VRFs). STUDY DESIGN: Data from comparative and noncomparative studies investigating CBCT, conventional radiography, or both for the diagnosis of VRFs were searched. The main outcome variables were sensitivity, specificity, and accuracy of the techniques. Data were separated into 4 groups: in vivo, ex vivo/untreated teeth, ex vivo/treated teeth, and ex vivo with post. The weighted mean of each parameter was estimated. RESULTS: Twelve articles were considered for the analysis. There was a large heterogeneity of the characteristics of the studies and a wide variability in outcome variables. No significant differences were found between radiographic techniques. CONCLUSIONS: No superiority of CBCT compared with conventional radiography was found for VRF detection. Adequate choice of voxel size seems to be important when diagnosing VRFs.

The dynamics of periapical lesions in endodontically treated teeth that are left without intervention: a longitudinal study.

INTRODUCTION: The long-term dynamics of periapical lesions in endodontically treated teeth is not fully elucidated, thus presenting a clinical dilemma regarding the need for an intervention. The aim of the study was to retrospectively evaluate the long-term dynamics of periapical lesions that were left without intervention in endodontically treated teeth. METHODS: Periapical status surveys of patients treated in a public dental clinic were retrospectively evaluated for the presence of periapical lesions in endodontically treated coronally restored teeth. The dynamics of the included periapical lesions was evaluated based on the periapical index (PAI) score changes between 2 consecutive periapical surveys of at least a 4-year interval. The influence of various factors on lesion dynamics was statistically evaluated. RESULTS: The study cohort consisted of 74 patients with a total of 200 endodontically treated teeth having periapical lesions that fulfilled the inclusion criteria. Fifty-seven (28.5%) lesions remained unchanged, 103 (51.5%) lesions worsened (PAI score increased), and 40 (20%) lesions improved (PAI score decreased). Poor root canal filling and poor restoration were found to adversely affect the long-term dynamics of the periapical lesions (P < .05). Age, sex, and the presence of a post had no statistically significant influence on lesion dynamics (P > .05). CONCLUSIONS: Poor root canal filling and poor restoration may adversely affect the long-term dynamics of periapical lesions that are left without intervention in endodontically treated teeth. Therefore, in cases of poor root canal filling or poor restoration, further intervention may be indicated.

Fracture mechanics analysis of vertical root fracture from condensation of gutta-percha.

A two-dimensional fracture mechanics analysis of vertical root fracture (VRF) in single-canal roots from apical condensation of gutta-percha (gp) is developed. The resulting analytic relation for apical load causing VRF agrees with major trends reported in in-vitro tests on roots subjected to either continuous or, the more clinically relevant, repeating vertical condensation of gp. The model explicitly exposes the role of root canal morphology and dentin fracture toughness on VRF. Ovoid and irregular canals are prone to fracture while the effect of mean root canal radius is modest. Canal taper and instrumentation details may affect VRF only marginally and indirectly. The model predicts dentinal cracks to occur following root canal instrumentation and obturation, which may pose long-term threats to tooth integrity.

Effect of guided tissue regeneration on the outcome of surgical endodontic treatment: a systematic review and meta-analysis.

INTRODUCTION: The use of guided tissue regeneration (GTR) techniques has been proposed as an adjunct to endodontic surgery in order to promote bone healing. Studies assessing the added benefits of GTR for the outcome of endodontic surgery are significantly variable in their treatment protocols, follow-up periods, and inclusion criteria, thus generating inconsistent and confusing results. The aim of this study was to evaluate the influence of GTR on the outcome of surgical endodontic treatment by means of a systematic review of the literature and meta-analysis. METHODS: An exhaustive literature search combined with strict inclusion and exclusion criteria was undertaken to identify clinical studies that assessed the added benefit of GTR in endodontic surgery. RESULTS: A trend of better outcome was found when GTR was used compared to control cases, but the results were not statistically significant. Lesion size, lesion type, and membrane type were identified as factors significantly affecting the outcome of GTR versus control cases. GTR techniques favorably affected the outcome of surgical endodontic treatments in cases of large periapical lesions and through-and-through lesions. A favorable outcome was found when using a resorbable membrane over using a nonresorbable membrane or graft alone. CONCLUSIONS: GTR techniques may improve the outcome of bone regeneration after surgical endodontic treatments of teeth with certain lesions. Additional large-scale prospective clinical studies are needed to further evaluate possible benefits of GTR techniques in endodontic surgery.

Diagnosis of vertical root fractures in endodontically treated teeth based on clinical and radiographic indices: a systematic review.

INTRODUCTION: The diagnosis of vertical root fracture (VRF) is at times complicated for lack of specific signs, symptoms, and/or radiographic features. The purpose of this study was to systematically search and evaluate the literature regarding the diagnostic accuracy of clinical signs and symptoms and radiographic indices for the diagnosis of VRF in endodontically treated teeth by means of a systematic review. METHODS: An exhaustive literature search combined with strict inclusion and exclusion criteria was undertaken to identify clinical studies that assessed the diagnosis of VRF. RESULTS: There is no substantial evidence regarding the accuracy of the clinical and radiographic indices for the diagnosis of VRF in endodontically treated teeth. CONCLUSIONS: Evidence-based data concerning the diagnostic accuracy and clinical effectiveness of clinical and radiographic dental evaluation for the diagnosis of VRF in endodontically treated teeth are lacking. The need for evidence-based research efforts to elucidate the currently unknown situation is of utmost significance.

A new surgical technique for preservation of endodontically treated teeth with coronally located vertical root fractures: a prospective case series.

OBJECTIVE: The purpose of this study was to present a new surgical preservation technique for teeth with incomplete vertical root fracture. STUDY DESIGN: Seventeen patients with 1 endodontically treated maxillary anterior tooth in which an incomplete vertical root fracture involving only the buccal side was suspected underwent a flap elevation procedure to visualize the pattern of bone loss and assess the type of root fracture. If the preoperative diagnosis was confirmed, a groove following the fracture line was prepared using retro-tips driven by an ultrasonic device and sealed with mineral trioxide aggregate after filling of the bone defect with calcium sulfate. RESULTS: A total of 10 vertical root fracture repair procedures were performed. At 12 months' follow-up, all cases showed clinical and radiographic success. After 33 months, 7 patients were available for a follow-up: 5 cases remained successful, and 2 teeth (lateral incisors) failed. CONCLUSIONS: The present surgical approach for preservation of teeth with incomplete vertical root fracture demonstrated satisfactory results regarding clinical outcome.

Comparison of digital with conventional radiography in detection of vertical root fractures in endodontically treated maxillary premolars: an ex vivo study.

OBJECTIVE: The purpose of the present study was to compare the diagnostic ability of conventional intraoral film radiography and a charged-coupled device (CCD) sensor in detecting vertical root fractures (VRF) in endodontically treated single-rooted extracted human maxillary premolars. STUDY DESIGN: The study consisted of 60 extracted single-rooted endodontically treated maxillary premolars: 30 with clinically confirmed VRF (experimental group) and 30 with no VRF (control group). An intraoral CCD sensor and conventional Kodak Insight Film were used. Two observers evaluated the digital and conventional radiographs twice with an interval of 4 weeks. Specificity and sensitivity for each radiographic technique were calculated and subjected to statistical analysis. Kappa values were calculated for intra- and interobserver agreement. Fisher's exact test was used to evaluate detection of VRF. The overall differences in sensitivity and specificity between radiographic techniques were evaluated by McNemar test. RESULTS: The specificity of the digital system was significantly better (P = .016) for the second observer at the first reading. There were no significant differences in sensitivity and specificity for both observers between the 2 systems for other readings (P > .05). CONCLUSIONS: No difference was found between the intraoral CCD sensor and conventional radiography in detecting vertical root fractures for single rooted maxillary premolars ex vivo.

Radiographic features of vertically fractured endodontically treated mesial roots of mandibular molars.

OBJECTIVE: The purpose of this study was to evaluate the most frequent radiographic appearance of bony lesions around endodontically treated vertically fractured mesial roots of mandibular molars. STUDY DESIGN: For the study, 49 extracted mesial roots with vertical fractures (study group) were evaluated and compared to 52 extracted roots without fractures (control). RESULTS: The "halo" (36.7%) and "periodontal" (28.6%) type radiolucencies were the most typical appearances of periradicular areas around the mesial roots of mandibular molars with vertical root fractures. By itself, bifurcation radiolucency was statistically insignificant (6.1%), however in conjunction with other areas of radiolucency, it was significant (63.3%, P < .0378). No radiolucency (38.5%) and periapical radiolucency (32.7%) were predominant features in the control (nonfractured roots). Amalgam dowel in the coronal part (1-2 mm) of the root was found in 67.3% of the vertically fractured roots (P < .0006). Defined but not corticated (57.2%) or diffuse (32.6%) borders were typical for vertically fractured mesial roots. CONCLUSIONS: The use of significant variables, such as "periodontal" and "halo" bony radiolucencies, bifurcation involvement, and the presence of amalgam dowel, has prediction sensitivity of 77.6% (VRF group) and specificity of 82.7% (nonfractured roots).