Sinus membrane thickness of healthy endodontically treated maxillary molars.

OBJECTIVE: The study aimed to investigate the sinus membrane thickness (SMT) adjacent to healthy endodontically-treated maxillary molars with or without protruded apical foramen into the sinus cavity using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Images of 207 non-smoker patients aged 18-40 were retrospectively analyzed, 140 were endodontically treated, and 136 were without endodontic treatment. Patients with any sinus pathology, teeth that have symptoms, or poor root filling were excluded. Study groups consisted of Group EM-I (endodontically treated and protruded apical foramen), Group EM-C (endodontically treated and contacted apical foramen), and similarly without endodontic treatment; Group M-I and Group M-C. SMT upon the mesial, distal, and palatal roots was measured. One-way ANOVA and Student's t-tests were performed. RESULTS: Group EM-I had the thickest sinus membrane compared to other groups (p = 0.013). SMT values were 2.37-2.60 mm in Group EM-I, and 1.34-1.58 mm in other groups. Thickening (> 2 mm) percentages were 33.45% in Group EM-I and between 4.25 and 8.25% in other groups. No statistical difference was detected between first and second molars and genders (p > 0.05). CONCLUSION: When the apical foramen protruded into the sinus cavity, the conventional root canal treatment caused a minimal (between 2.37 mm and 2.60 mm) sinus membrane thickening with a rate of 33.45% based upon CBCT examinations.

Periapical Lesions and Missed Canals in Endodontically Treated Teeth: A Cone-Beam Computed Tomographic Study of a Chinese Subpopulation.

BACKGROUND Periapical lesions (PL) are a common complication of endodontically treated teeth (ETT), which can result from a missed canal (MC). This study aimed to assess the prevalence of PL and MC in the ETT of a Chinese subpopulation and investigate potential associations between them. MATERIAL AND METHODS A total of 561 cone-beam computed tomography images were selected and analyzed. A total of 1024 endodontically treated posterior teeth excluding third molars were evaluated for the presence of PL and MC. The chi-square test or Fisher's exact test, as well as the odds ratio test, were used to determine whether there was an association and risk relationship between the incidence of PL and the occurrence of MC. RESULTS The overall prevalence of PL and MC in ETT was 56.1% and 19.0%, respectively. In endodontically treated molars, the incidence of PL and MC was 64.1% and 27.6%, whereas in premolars, it was 42.1% and 4.27%. The maxillary first molar showed the highest frequency of PL (71.5%) and MC (65.7%), with the mesiobuccal second canal being the most missed (78.8%). Teeth with an MC were found to be 3.658 times (95% confidence interval=2.541-5.301, P<0.0001) more likely to be associated with a PL. CONCLUSIONS Endodontically treated teeth with missed canals are associated with higher risks of periapical lesions. The high prevalence of these complications in a Chinese subpopulation underscores the importance of implementing enhanced diagnostic and treatment methods for root canal treatment or retreatment.

Diagnostic efficacy of cone-beam computed tomography for detection of vertical root fractures in endodontically treated teeth: a systematic review.

BACKGROUND: Vertical root fractures (VRFs) sometimes occur in endodontically treated teeth. They have a difficult diagnosis and a dismal result. The objective of this review was to evaluate the diagnostic performance of cone-beam computed tomography (CBCT) for detecting VRFs in teeth that had undergone endodontic treatment. METHODS: Literature was reviewed from Web of Science, PubMed, Cochrane Review, SCOPUS, and Embase databases between 2000 and 2022. The searched keywords included "endodontically treated teeth," "cone-beam computed tomography," "CBCT," "tooth fracture," "vertical root fracture," "VRF," "accuracy," "sensitivity," and "specificity." Only articles in the English language were included. The final analysis included 20 papers that satisfied the eligibility requirements. RESULTS: The overall mean ± SD values (%) for the diagnostic sensitivity and specificity of CBCT for detection of VRFs in endodontically treated teeth in the presence of root-filling materials without an intracanal post were 71.50 ± 22.19 and 75.64 ± 19.41, respectively. The overall mean (SD) value (%) for the sensitivity of CBCT for the detection of VRFs in the presence of root-filling materials and intracanal posts was 72.76 (18.73), while the mean (SD) specificity was 75.44 (18.26). The accuracy of CBCT (mean ± SD) was 78.47 ± 17.19% and 74.02 ± 10.64%, respectively, for teeth without intracanal posts and those with posts. CONCLUSIONS: Further clinical research is needed to validate the optimum efficiency of CBCT as a diagnostic technique for detecting VRFs in teeth that have had endodontic treatment, given the low sensitivity, significant heterogeneity of studies, and lack of in-vivo studies on the subject.

Root filled teeth in two parallel Danish cohorts: A repeated longitudinal cohort study.

AIM: The aim of the study was to compare the frequency of root filled teeth and quality of root fillings (RFs) in two parallel, Danish cohorts each examined over 10 years and to evaluate factors associated with apical periodontitis (AP) and extraction of root filled teeth. METHODOLOGY: Two randomly selected cohorts (C1, C2) from Aarhus (age: 20-64 years) were followed for approximately 10 years, with full-mouth radiographic surveys performed at 5-year intervals (C1: 1997-2003-2008; C2: 2009-2014-2019). Frequency of root filled teeth, quality of RFs and coronal restorations, periapical status and tooth extraction were registered. Logistic regression analyses compared C1 with C2 for baseline and follow-up periods and assessed variables associated with AP (PAI-based) and extraction of root filled teeth. RESULTS: C1 included 330 and C2, 170 individuals, mean age 42.9 and 47.3 years, respectively, who attended all three radiographic examinations. The relative frequency of root filled teeth was lower in C2 than C1 at baseline (C1: 4.7%, C2: 3.6%; p < .001) and after 10 years (C1: 5.7%, C2: 4.2%; p < .001). The relative frequency of new RFs was lower in C2 than in C1 (p = .02). C2 had fewer short/long RFs at baseline than C1; quality of new RFs or coronal restorations was similar in C1 and C2. The risk of tooth extraction (p = .93) and risk of AP (p = .37) at 10-year follow-up was similar between the two cohorts. For both C1 and C2, root filled teeth with AP at baseline had increased risk of having AP (p < .001) or having been extracted (p < .001) at follow-up. Risk of extraction was higher for root filled premolars (p = .01) and molars (p = .01) than anteriors. Risk of AP at follow-up was higher for root filled molars (p < .001). Furthermore, inadequate quality of RFs (p = .02) and coronal restorations (p = .04) increased the risk of AP at follow-up in C1 and C2. CONCLUSIONS: The frequency of root filled teeth and new RFs decreased and little to no change in new RFs' quality, AP, or tooth extraction was seen over time (1997-2019). Root filled molars and teeth with AP at baseline had increased risk of AP and extraction.

Evaluation of 3D MRI for early detection of bone edema associated with apical periodontitis.

OBJECTIVES: To detect and evaluate early signs of apical periodontitis using MRI based on a 3D short-tau-inversion-recovery (STIR) sequence compared to conventional panoramic radiography (OPT) and periapical radiographs in patients with apical periodontitis. MATERIALS AND METHODS: Patients with clinical evidence of periodontal disease were enrolled prospectively and received OPT as well as MRI of the viscerocranium including a 3D-STIR sequence. The MRI sequences were assessed for the occurrence and extent of bone changes associated with apical periodontitis including bone edema, periradicular cysts, and dental granulomas. OPTs and intraoral periapical radiographs, if available, were assessed for corresponding periapical radiolucencies using the periapical index (PAI). RESULTS: In total, 232 teeth of 37 patients (mean age 62±13.9 years, 18 women) were assessed. In 69 cases reactive bone edema was detected on MRI with corresponding radiolucency according to OPT. In 105 cases edema was detected without corresponding radiolucency on OPT. The overall extent of edema measured on MRI was significantly larger compared to the radiolucency on OPT (mean: STIR 2.4±1.4 mm, dental radiograph 1.3±1.2 mm, OPT 0.8±1.1 mm, P=0.01). The overall PAI score was significantly higher on MRI compared to OPT (mean PAI: STIR 1.9±0.7, dental radiograph 1.3±0.5, OPT 1.2±0.7, P=0.02). CONCLUSION: Early detection and assessment of bone changes of apical periodontitis using MRI was feasible while the extent of bone edema measured on MRI exceeded the radiolucencies measured on OPT. CLINICAL RELEVANCE: In clinical routine, dental MRI might be useful for early detection and assessment of apical periodontitis before irreversible bone loss is detected on conventional panoramic and intraoral periapical radiographs.

A digital technique for a prefabricated custom post-and-core restoration.

This technique provides a prefabricated and custom post-and-core to restore endodontically treated teeth to be delivered at the preparation appointment. Cone beam computed tomography (CBCT) is used to extract the post shape from a root canal, and a computer-aided design and computer-aided manufacturing (CAD-CAM) software program is used to design the core. The post and the core are combined and milled before post space preparation. Three-dimensional preparation guides are fabricated and used in post space preparation to ensure that the prefabricated and custom post-and-core fits after the preparation. This technique can save time and reduce the risk of perforation while preparing the root canal.

Effect of orthodontic treatment on the periapical radiolucency of endodontically treated teeth: a CBCT analysis.

BACKGROUND: This study aimed to evaluate periapical radiolucency of endodontically treated teeth before and after orthodontic treatment using cone-beam computed tomography (CBCT). METHODS: Patients who underwent orthodontic treatment at Wonkwang University Daejeon Dental Hospital between January 2009 and June 2022 were included based on the following criteria: root canal treatment, and availability of CBCT images taken before and after orthodontic treatment with an interval of > 1 year between both scans. Patients with primary teeth or orthodontic tooth extractions were excluded. The size of the periapical radiolucency (SPR) of the endodontically treated tooth was evaluated using CBCT. Pre-orthodontic treatment CBCT images and the latest post-orthodontic treatment CBCT images were analyzed. The selected teeth were further categorized based on the orthodontic duration, CBCT interval, the patient sex and age, the tooth type and position (maxilla or mandible), and quality of root canal obturation. Statistical analyses were performed to evaluate changes in SPR using the paired t-test and multiple regression analysis. RESULTS: In total, 115 teeth (37 anterior teeth, 22 premolars and 56 molars) from 61 patients (age, 14-54 years) were included, with 39 teeth from male patients and 76 teeth from female patients. The age was ranged between 14 and 54 years old, and mean age was 25.87 years old. The mean CBCT interval and orthodontic treatment period were 43.32 months and 36.84 months, respectively. Seventy-five teeth showed good obturation quality, 80 were not used as anchors during orthodontic treatment, and 71 were maxillary. The SPR size increased after orthodontic treatment for 56 teeth and decreased for 59 cases. The average change in SPR was -0.102 mm and the difference was not significant. Significant decrease of SPR were observed between female patients (p = 0.036) and maxillary teeth (p = 0.040). CONCLUSION: Orthodontic treatment had no significant impact on the changes in the SPR in endodontically treated teeth in most categories. However, there was a significant difference among females and the maxillary teeth. In both categories, the size of radiolucency decreased significantly.

Radiological Assessment of Prevalance and Quality of Periapical Status of Endodontic Treatments.

BACKGROUND The aim of this study was to determine the current prevalence and quality of endodontic treatments and investigate the relationship of various factors with posttreatment endodontic disease (PTED) in a Turkish subpopulation. MATERIAL AND METHODS The cone beam computed tomography (CBCT) images of 1069 patients (male, 50.9%; female, 49.1%; mean age, 45.32±13.50 years) were retrospectively analyzed. A total of 20 646 teeth were examined; 1604 had undergone root canal. Periapical status was assessed using a modified CBCT periapical index. The relationship between periapical status and quality of root canal fillings (RCFs) was analyzed statistically using the chi-square test. Multivariate logistic regression was performed to evaluate the effect of individual parameters by adjusting them for other variables. RESULTS A total of 7.8% of all teeth had RCF. The prevalence of poor filling (having at least 1 procedural error) was 54.1%; the prevalence of PTED was 56.8%. The prevalence of PTED was 44.3% in teeth with short RCF, 10.8% with overextended RCF, 35.7% with nonhomogeneous RCF, and 15.5% in teeth with untreated root canals. The rate of RCF teeth with procedural errors associated with PTED was 76.2%. There was no significant difference between sexes in apical periodontitis (P>0.05), which developed more frequently in teeth with procedural errors. CONCLUSIONS The overall prevalence of poor fillings (having at least 1 procedural error) among RCF teeth was high (54.1%) in this subpopulation. There is a substantial need to improve the technical quality of endodontic treatment.

Radiographic outcomes and prognostic factors in nonvital immature permanent teeth after apexification with modified calcium hydroxide paste: a retrospective study.

OBJECTIVE: To assess the radiographic outcomes and prognostic factors in nonvital immature permanent teeth after apexification with modified calcium hydroxide paste. MATERIALS AND METHODS: Clinical and radiographic data were collected from 115 necrotic immature permanent teeth (71 caused by trauma and 44 caused by dens evaginatus) treated with apexification using a modified calcium hydroxide. Postoperative root morphology and changes in radiographic root area (RRA) on periapical radiographs were determined and statistically evaluated. Regression analysis was performed to identify factors associated with the outcomes of apexification. RESULTS: The average time for a calcified barrier formation was 10.66 ± 6.37 months. The root morphology after apexification with calcium hydroxide + iodoform paste was similar to that previously described after calcium hydroxide apexification. Compared with the trauma cases, the dens evaginatus cases revealed more type I (40.91% vs 16.9%) and less type II morphology (45.45% vs 67.61%). Although the changes in RRA were limited, the dens evaginatus cases showed greater increment of RRA than the trauma cases (4.12% ± 5.58% vs 0.70% ± 5.21%, P < 0.001). A significant association was found between the preoperative stage of root development and postoperative percentage change in RRA (P < 0.001). CONCLUSIONS: Teeth caused by dens evaginatus had better outcomes after apexification than teeth caused by trauma. Early stages of root development were associated with superior radiographic outcomes. CLINICAL RELEVANCE: Apexification provided reliable outcomes in the treatment of immature teeth with pulp necrosis and apical periodontitis, even though the root development is limited. Treatment decision should be made with comprehensive evaluation of prognostic factors.

Dentin thickness as a risk factor for vertical root fracture in endodontically treated teeth: a case-control study.

OBJECTIVES: This study evaluated factors associated with vertical root fracture in endodontically treated teeth, using a cone-beam computed tomography (CBCT) image database. MATERIALS AND METHODS: The sample for this case-control study consisted of 81 CBCT scans of teeth with vertical root fracture (VRF) and 81 CBCT scans of non-fractured teeth, matched by age, sex, and tooth position. The analyzed variables included dentin thickness, an intraradicular post, an adjacent implant, and a missing adjacent tooth. Student's t test test was used to compare the quantitative variables. The chi-square test was used to compare the categorical variables. Logistic regression was performed to evaluate the association between the presence of VRF and the independent factors assessed. RESULTS: The mean dentin thickness of fractured teeth was 1.3 mm, whereas that of non-fractured ones was 1.5 mm (p < 0.001). There was no difference between the fractured and non-fractured groups, regarding implant frequency or missing adjacent tooth (p > 0.05). There were a significantly larger number of teeth with posts in the fractured versus non-fractured group (p = 0.007). However, dentin thickness ≤ 1.3 mm was the only factor associated with VRF in the multiple regression model (OR = 3.60, 95%CI = 1.76-7.37). CONCLUSIONS: Dentin thickness may influence the development of VRF. Dentin thickness ≤ 1.3 mm is associated with a greater likelihood of fracture than ≥ 1.4 mm. CLINICAL RELEVANCE: This study suggests there may be a minimum amount of safe dentin thickness that should be preserved after endodontic instrumentation.

The influence of voxel size and artifact reduction on the detection of vertical root fracture in endodontically treated teeth.

OBJECTIVE: The aim of this study was to evaluate the effect of voxel size and artefact reduction (AR) on the identification of vertical root fractures (VRFs) in endodontically treated teeth. METHODS: A total of a hundred sound, extracted human mandibular single-rooted premolars were decoronated, after which root canal preparation was performed, canals were filled with gutta percha by single cone technique. Randomly selected fifty specimens were fractured, repositioned and glued together. The teeth were examined with cone beam computed tomography (CBCT) in five different voxel sizes (0.125, 0.200, 0.250, 0.300, and 0.400 voxels). Two scans were performed for each tooth, one with AR and one without AR. Two radiologists evaluated the CBCT scans. RESULTS: All voxel dimensions were successful in detecting VRFs in CBCT scans. But as the voxel size increased, the percentage of detecting VRFs decreased. High accuracy, sensitivity, specificity and predictive values were found for VRF detection on CBCT scans. Accuracy and sensitivity values decreased (from 100 to 82) while voxel dimensions increased (from 0.125 to 0.400). High-resolution images (0.125, 0.200, and 0.250 voxels) caused an increase in sensitivity for detection of VRFs. AR did not affect the accuracy, sensitivity, specificity and predictive values for VRF detection on CBCT scans. CONCLUSIONS: High-resolution CBCT images resulted in an increase in sensitivity and specificity for detection of VRFs compared with lower-resolution CBCT images. The use of AR did not further improve its diagnostic potential.

The Development of Large Radicular Cysts in Endodontically Versus Non-Endodontically Treated Maxillary Teeth.

Background and Objectives: Large radicular cysts of the maxilla present a clinical challenge, as they may cause recurrent infection, severe alveolar bone loss and disruption of the nasal and maxillary sinus floors. The aim of this study was to evaluate the effect of previous root canal treatment on the clinical presentation of large maxillary radicular cysts. Materials and Methods: All cases of radicular cysts treated at the Oral and Maxillofacial Surgery Department of a tertiary public hospital over a period of six years (2012-2018) were evaluated. Histologically confirmed radicular cysts of the maxilla with a maximal dimension of over 15 mm were included. Demographic data of the patients, clinical presentation and radiographic features of the lesions were analyzed. Results: A total of 211 inflammatory cysts were treated in the study period, of these 54 histologically diagnosed radicular cysts in the maxilla were found to have a maximal dimension of over 15 mm. The mean age of patients with large maxillary radicular cysts was 43.3 years, 57.6% of which were male and 42.4% female. The lateral incisor was the most common tooth affected (46.3%). The mean size of the large radicular cysts was 25 mm. Then, 83.8% of the cysts were observed in teeth with previous endodontic treatment. Teeth without endodontic treatment presented clinically with significantly fewer acute symptoms in comparison to teeth with previous endodontic treatment. Conclusions: the vast majority (83.8%) of large maxillary radicular cysts were associated with endodontically treated teeth. Previous endodontic treatment was correlated to increased frequency of clinical symptoms.

Apical fenestration in endodontically treated teeth: A report of two cases.

Root canal therapy in teeth with root fenestrations can present with pain on apical palpation or persistent pain. The signs and symptoms of root fenestration in the absence of mucosal fenestration may be misleading, which may be misdiagnosed as non-odontogenic pain. Although CBCT is superior to periapical radiographs for the diagnosis of root fenestration, it failed to detect the intact cortical plate in the middle third in our cases. Therefore, the type was different in CBCT from its actual size surgically. Repeated non-surgical root canal treatment would not alleviate pain in the presence of root fenestration and may lead to apical root fracture. Root-resection relieves pain, unless the fenestration is accompanied by fracture. The aim of these two case reports was to describe the diagnosis and treatment of endodontically treated teeth with a persistent pain. Also, the difference of root fenestration type between CBCT and its actual size was described.

Hard X-ray phase-contrast-enhanced micro-CT for quantifying interfaces within brittle dense root-filling-restored human teeth.

Bonding of resin composite fillings, for example following root-canal treatment, is a challenge because remaining gaps grow and lead to failure. Here, phase-contrast-enhanced micro-computed tomography (PCE-CT) is used to explore methods of non-destructive quantification of the problem, so that countermeasures can be devised. Five human central incisors with damaged crowns were root-filled followed by restoration with a dental post. Thereafter, the crowns were rebuilt with a resin composite that was bonded conventionally to the tooth with a dental adhesive system (Futurabond U). Each sample was imaged by PCE-CT in a synchrotron facility (ID19, European Synchrotron Radiation Facility) with a pixel size of 650 nm. The reconstructed datasets from each sample were segmented and analysed in a semi-automated manner using ImageJ. PCE-CT at sub-micrometre resolution provided images with an impressive increased contrast and detail when compared with laboratory micro-computed tomography. The interface between the dental adhesive and the tooth was often strongly disrupted by the presence of large debonded gaps (on average 34% ± 15% on all surfaces). The thickness of the gaps spanned 2 µm to 16 µm. There was a large variability in the distribution of gaps within the bonding area in each sample, with some regions around the canal exhibiting up to 100% discontinuity. Although only several micrometres thick, the extensive wide gaps may serve as gateways to biofilm leakage, leading to failure of the restorations. They can also act as stress-raising `cracks' that are likely to expand over time in response to cyclic mechanical loading as a consequence of mastication. The observations here show how PCE-CT can be used as a non-destructive quantitative tool for understanding and improving the performance of clinically used bonded dental restorations.

Is the technical quality of root fillings associated with socioeconomic status? A cross-sectional study among Finnish adults.

We investigated differences in the technical quality of root fillings according to socioeconomic status. In the Finnish Health 2000 Survey, which comprised a sample of 8,028 adults aged over 29 yr, 6,115 underwent panoramic radiography. A total of 7,986 endodontically treated teeth were detected among 3,095 participants. The criterion for a technically inadequate root filling was a distance from the root filling to the root apex of over 3 mm or a filling extruding beyond the apex. Educational level, employment status, and income were the measures of socioeconomic status. Differences in the frequency of inadequate root fillings according to socioeconomic status were investigated using a multilevel logistic mixed-effects model taking into account age, gender, number of teeth, and type of root filled tooth. Almost half (46%) of the root fillings were inadequate. Among the over 64-yr-olds, higher education and higher income were associated with a higher probability of having an inadequate root filling. Among the under 65-yr-olds, socioeconomic status was not associated with root filling quality. Contrary to expectation, lower socioeconomic status was not associated with poorer endodontic treatment quality; however, higher income and higher education was associated with higher odds for inadequate root fillings among the over 64-yr-olds.

The dimensions of the facial alveolar bone at tooth sites with local pathologies: a retrospective cone-beam CT analysis.

OBJECTIVE: To assess the impact of various local pathologies on facial alveolar bone dimensions at tooth sites. MATERIALS AND METHODS: Cone-beam computed tomography images of 60 patients were analyzed. Healthy teeth and teeth with local pathologies (i.e., endodontically treated, periodontally diseased teeth, and teeth with periapical lesions) were included. The thickness of the facial alveolar bone was measured at five locations: (1) the bone crest (W0), (2) 25% (W25), (3) 50% (W50), (4) 75% (W75) of the distance from the bone crest to the root apex (A), and (5) in the A region (W100). The results were considered statistically significant at p < 0.0008 (adjustment according to the statistical correction for multiple testing). RESULTS: A total of 1174 teeth (707 healthy and 467 with the local pathologies) were assessed. Periodontally diseased maxillary premolars and anterior teeth in the mandible in the W0 position, as well as maxillary molars in the W25 position, tended to have a lower facial bone thickness when compared to the healthy teeth (0.68 mm vs. 0.84 mm, p = 0.008; 0.47 mm vs. 0.55 mm, p = 0.004; and 1.27 mm vs. 1.72 mm; p = 0.009, respectively). In contrast, the observed tendency pointed towards thicker facial bone wall for the periodontally diseased mandibular anterior teeth in the W50 position (0.74 vs. 0.52, p = 0.001). Healthy maxillary molars tended to display a thicker facial alveolar bone compared to the teeth with local pathologies in the W25, W50, and W75 positions (p = 0.001, p = 0.005, and p = 0.004, respectively). CONCLUSIONS: The present analysis has indicated that local pathologies are commonly associated with a compromised socket morphology. CLINICAL RELEVANCE: The facial bone thickness was particularly reduced at periodontally diseased teeth, which may challenge implant therapy.

Influence of the coronal restoration on the outcome of endodontically treated teeth.

Objective: The tooth weakens due to removal of hard tissue during an endodontic procedure. Many dentists find it difficult to choose between different coronal restorations after root canal treatment (RCT). Studies show that the coronal restoration may affect the endodontic prognosis. This student-based study had three aims. (1) Examine the choice of coronal restoration of endodontically treated teeth at a Scandinavian dental school, (2) examine the survival of these restorations and (3) evaluate the influence of the coronal restoration on the outcome of the RCT. Material and methods: Radiographic and clinical examination was performed on 127 posterior teeth. The quality of the root canal treatment and the periapical status (PAI-index) were evaluated. Results: 43.8% of the teeth were restored with an indirect coronal restoration and 47.2% with a direct coronal restoration. The period from finished root canal treatment until placement of a permanent coronal restoration was significantly longer for an indirect restoration than a direct restoration. The teeth treated with a PAI score of 1 and 2 following pulpectomy, necrotic pulp treatment and endodontic retreatment was 93.8%, 82.6% and 69.4%, respectively.Conclusion: There was no significant association between choice of coronal restoration and PAI-score.

Influence of cervical preflaring and root canal preparation on the fracture resistance of endodontically treated teeth.

BACKGROUND: Evaluate the fracture resistance of endodontically treated teeth after cervical preflaring and root canal preparation and to assess the volume of the root canal and the amount of remaining root dentin before and after cervical preflaring. METHODS: Forty-four mandibular incisors were selected using micro-CT scanning and distributed into 4 groups (n = 11) according to the instrument used for cervical preflaring: control group - no cervical preflaring; Gates Glidden - burs size #2 and #3; WXN - 25.07 Navigator instrument; and Easy - 25.08 ProDesign S instrument. Coronal opening was performed, and the canals were prepared with Wave One Gold Primary and filled with an epoxy-resin based sealer and gutta-percha cones. Micro-CT scans were performed before and after root canal instrumentation. All images were reconstructed and assessed for the thickness of mesial and distal root dentin at 3 mm and 5 mm from the cement -enamel junction and for the volume of cervical portion of the canal after preparation. Fracture resistance test was performed applying compressive loads at a crosshead speed of 0.5 mm/min, applied on the palatal aspect of specimens at 135° along the long axis of the tooth. The data were analyzed using ANOVA and Tukey's test (P = .05). RESULTS: Cervical preflaring and canal preparation reduced the dentin thickness (P < .05) and increased the canal volume (P < .05) in all groups at 3 mm an 5 mm. Cervical preflaring with Gates Gliden burs reduced the fracture resistance of endodontically treated teeth (P < .05). CONCLUSIONS: All instruments reduced the dentin thickness and increased the canal volume in the cervical at 3 mm and 5 mm. Gates Glidden reduced fracture resistance of mandibular incisors submitted to cervical preflaring, whereas NiTi instruments did not. CLINICAL RELEVANCE: Cervical preflaring assumes particular importance previously to the root canal preparation because it minimizes the occurrence of operative accidents, and permits more accurate determination of working length and the apical diameter.

Odontological identification dental charts based upon postmortem computed tomography compared to dental charts based upon postmortem clinical examinations.

Since the beginning of this century, the use of postmortem computed tomography (PMCT) in forensic autopsies has increased. In this study we examined how similar dental charts created using PMCT as a solitary examination mode were to dental charts created using the conventional method of a clinical inspection including intraoral radiographs. A total of 100 previously performed dental identification cases were retrospectively included in the study. For each case, a dental chart was created solely based upon PMCT. The PMCT based dental chart was subsequently compared with the chart created from the previous conventional identification examination. Based upon the accuracy, sensitivity and specificity values PMCT performed very well compared to the conventional method in the identification concerning presence or absence of teeth, the presence of crowns, bridges and endodontic treatments as well as the presence and types of fillings. PMCT performed poorly concerning the extension of fillings and identification of small, tooth-colored fillings. The use of PMCT is a valuable supplement to the conventional methods available for forensic odontologists and may be of great value for initial screening in mass fatalities.

Presentation of gaps around endodontic access cavity restoration by phase contrast-enhanced micro-CT.

OBJECTIVE: To evaluate the feasibility of synchrotron-based phase-contrast (PC) µCT for visualization of the gaps and differentiation between the gaps, restorative, and endodontic materials at the tooth-restoration interface. MATERIALS AND METHODS: Standardized access cavities were prepared in human maxillary molars and subjected to materials, simulating endodontic treatment: (1) saline irrigation; (2) NaOCl and 17% EDTA irrigation; (3) same as group 2, followed by application of Ca(OH)2; and (4) same as group 2, followed by application of root canal sealer. The access cavities were cleaned and restored using an etch-and-rinse adhesive and a composite material in multilayering technique. The samples were thermocycled (1000 cycles, 5-55 °C). Synchrotron-based µCT imaging was performed obtaining absorption and PC µCT images before and after the immersion of the samples into 50% AgNO3. PC µCT images were compared to absorption µCT and conventional optical microscopy images. RESULTS: PC µCT of unstained samples enabled the best visualization of gaps and differentiation of restorative and endodontic materials, contaminating the cavity surface. PC µCT revealed that AgNO3 staining leads to an overestimation of gap size due to anterograde and retrograde AgNO3 infiltration into dentinal tubules and underestimation of large gaps due to lack of AgNO3 penetration. CONCLUSION: Synchrotron PC µCT imaging enables better visualization of gap and differentiation of materials at the tooth-restoration interface. µCT imaging with AgNO3 staining has shown certain over- and underestimations. Future research should be aimed at incorporating PC µCT imaging of unstained samples for the validation of results obtained with other methods. CLINICAL SIGNIFICANCE: Contamination of cavity walls with an endodontic sealer or Ca(OH)2 leads to increased gap formation at the tooth-restoration interface.