The Effect of the Anatomic Variables on the Success Rate of Anesthesia in Maxillary Molars with Irreversible Pulpitis

IntroductionObtaining anesthesia of teeth with irreversible pulpitis is 1 of the most challenging issues in endodontic practice. The aim of this study was to evaluate the effect of anatomic variables on the success rate of anesthesia in maxillary molars with irreversible pulpitis.MethodsPatients who had maxillary molars with irreversible pulpitis and who had already had a cone-beam computed tomographic (CBCT) scan performed were included in this study. After infiltration injection of an anesthetic solution, the success rate of anesthesia was recorded by asking the patients to rate their pain during access cavity preparation and root canal instrumentation as well as their need for a supplementary injection during the treatment. The distance of the palatal root to the buccal cortical plate was calculated using the Romexis Viewer (Planmeca, Helsinki, Finland) measuring tools in both the axial and coronal views. Data were analyzed by chi-square and t tests as well as receiver operating characteristic curve analysis.ResultsForty-seven maxillary first and second molar teeth were eligible to be included in this study. The overall success rate of anesthesia was 63.80%. The palatal roots that had their apex located more than 12.34 mm from the buccal cortical plate in the axial view, and 12.46 mm in the coronal view had a higher chance of anesthesia failure compared with the teeth with smaller distances. The presence of the maxillary sinus between the cortical plate and roots had no significant impact on the efficacy of anesthesia (P > .05).ConclusionsThe potential of anesthesia failure during the treatment of irreversible pulpitis in maxillary molars with a divergent palatal root is significantly higher than in teeth with shorter distances from the palatal root apex to the buccal cortical plate. If a patient already had a CBCT scan done for other reasons or the CBCT is available in his or her records, a dental practitioner can use it to predict anesthesia success for maxillary molars with irreversible pulpitis.     

Evaluation of fracture resistance of pulpotomized second primary molars restored with fiber-reinforced composite

ObjectivesFiber reinforcement of composite restorations can help decrease the fracture risk in restored pulpotomized teeth with severe coronal lesions.This study aimed to evaluate the fracture resistance of pulpotomized second primary molars restored with fiber-reinforced composite (FRC).MethodsThis experimental study was done on 40 extracted primary second molars in four groups (n = 10). The negative controls were intact untreated teeth; while, other samples were pulpotomized with the mesio-occlusal-distal (MOD) access cavities prepared on their buccal and lingual surfaces. Positive control group was left unrestored. Composite group received glass ionomer on Zonalin and was restored with flowable composite and then composite. The FRC group received glass ionomer as the preceding group; the glass fiber was embedded within flowable composite, and the cavity was restored with composite. The compressive forces leading to fracture were recorded in Newton. Comparisons were made through one-way ANOVA and Tukey's post-hoc test (α = 0.05).ResultsThe highest mean fracture resistance belonged to the intact teeth (604.45 ± 59.02 N), then the FRC group (584.31 ± 57.18 N). Unrestored teeth had the lowest fracture resistance (235.60 ± 45.60 N); however, they were not significantly different from composite group in this regard (P = 0.47). Although FRC group had significantly higher fracture resistance than the unrestored and composite group, it was not significantly different from intact teeth.ConclusionsFiber reinforcement improved the fracture resistance of pulpotomized primary molar with large MOD cavities.     

CBCT Patterns of Bone Loss and Clinical Predictors for the Diagnosis of Cracked Teeth and Teeth with Vertical Root Fracture

IntroductionThis study aimed to identify clinical and radiographic characteristics of teeth with longitudinal fractures to assist in the diagnosis and differentiation between cracked teeth and teeth with vertical root fracture (VRF).MethodsNinety-five patients (95 teeth) diagnosed with a longitudinal fracture (only cracked teeth or VRF) through clinical visualization of the fracture line were included in this study. Clinical and radiographic data were collected from the patients' records to identify the characteristics associated with each condition. Fifty-four patients (54 teeth) had full radiographic (periapical [PA] radiography and a cone-beam computed tomographic [CBCT] scan) and clinical findings (probing depths and clinical images of the fracture line). PA and CBCT images were evaluated by 2 independent examiners to identify the different patterns of bone loss associated with these teeth (no defect, an angular defect, a J-shaped defect, or a combined defect). Cohen kappa analysis was used to compare the results between the 2 examiners and between the findings of the PA and CBCT images. Pearson chi-square analysis, the Fisher exact test, and adjusted Bonferroni post hoc testing were used to establish an association between the type and extension of the longitudinal fracture with the probing depth, the CBCT pattern of bony defects, and the presence/absence of the buccal plate and also to compare the clinical and radiographic characteristics of cracked teeth and teeth with VRF (P < .05).ResultsCBCT images had 4.4 times the odds of detecting bony defects suggestive of longitudinal fractures compared with PA radiographs. Teeth with VRF were more associated with indirect restorations, deep probing (>6 mm), absence of the cortical plate, and a J-shaped defect on the CBCT image (P < .05). On the other hand, cracked teeth were associated with direct restorations, shallow probing (<6 mm), an intact cortical plate, and the presence of an angular defect on the CBCT image (P < .001). There was a significant correlation between a radicular extension of the fracture line and deep probing as well as J-shaped defects (P < .05).ConclusionsPatterns of bone loss on CBCT imaging can likely differentiate between cracked teeth and teeth with VRF. The presence of an angular defect may suggest the presence of a crack in the tooth before intervention. J-shaped defects, deep probing (>6 mm), and loss of the cortical plate are likely suggestive of VRF.     

Incidence of Middle Mesial Canals Based on Distance between Mesial Canal Orifices in Mandibular Molars: A Clinical and Cone-beam Computed Tomographic Analysis

IntroductionThis study evaluated the presence of midmesial canals (MMCs) in a random sample of mandibular molars and the relationship of the intracanal distance between mesiobuccal (MB) and mesiolingual (ML) canal orifices.MethodsFifty-one extracted mandibular molars were divided into samples of 3 to 4 teeth, mounted in plaster and boxing wax, and immersed in water before cone-beam computed tomographic (CBCT) imaging. Two endodontic residents completed the access openings. The teeth and the CBCT images were interpreted for the presence of MMCs and the mesial intracanal distance. CBCT software measured the distance between the buccal of the MB canal to the lingual of the ML canal at the pulpal floor to determine the average length between the canals.ResultsSeven distinct MMCs were seen both clinically (incidence of 13.725%) and on the CBCT images. Twenty-seven teeth (52.94%) had ambiguous broad isthmi between the MB and the ML orifices. MMCs were present at the furcation level but merged with the MB or ML canal toward the apex in 6 of 7 teeth (85.71%). The mean distance between the mesial canals in teeth with MMCs was 3.643 mm, and it was 3.818 mm for teeth without MMCs. According to independent sample t testing, the P value was >.05.ConclusionsThe incidence of MMCs in mandibular molars appears consistent with the literature. However, there does not appear to be a statistically significant difference in the mesial intracanal distance in teeth with and without MMCs. Visualization of MMCs on CBCTs may be subjective. There does not appear to be a correlation between the presence of MMCs and an increased or decreased mesial intracanal distance.     

A Novel Simplified Workflow for Guided Endodontic Surgery in Mandibular Molars With a Thick Buccal Bone Plate: A Case Report

One of the challenges in apical surgery in mandibular molars is the thick buccal cortical bone plate, which might lead to access errors, damage to neighboring teeth, and injury to healthy tissue. Surgical guide templates with 3-dimensional (3D) impressions have been suggested for use in such cases, allowing greater precision. Usually, this technique involves a cone-beam computed tomography (CBCT) examination related to a 3D oral scanning to generate surgical templates printed from 3D imaging data. This study reports a novel workflow possibility in which apical surgery is performed with the aid of a surgical guide planned only with CBCT, excluding the need for 3D oral scanning. A 32-year-old woman presented with asymptomatic apical periodontitis and external root resorption on the mesial root of tooth #19. A surgical template was planned using only the patient's CBCT scan to provide precise access to the lesion and remove a mandibular cortical bone block. The procedure was carried out with apicoectomy, root-end preparation, and retrograde filling, and the bone block was repositioned before suture. No postoperative complications were reported. After 1 year, the patient presented asymptomatic, and a CBCT scan confirmed bone healing. The current 3D-printed guides may be planned and printed through a novel simplified workflow with a CBCT scan only, which allows its application in apical surgery for precise apex and surgical site location.     

Evaluation of tooth root surface area using a three-dimensional scanning technique and cone beam computed tomographic reconstruction in vitro

ObjectiveTo study the feasibility of measuring root surface area (RSA) by 3D scanning technique and cone beam computed tomography (CBCT) reconstruction in vitro.DesignTwenty extracted teeth (10 single-rooted teeth and 10 multi-rooted teeth) were collected in this study. The RSA of the extracted teeth was measured by the membrane technique, 3D scanning technique, and CBCT reconstruction. A standard part was also designed to check the accuracy of each method. All statistical analyses were performed using the SPSS software.ResultsAccording to the results of one-way ANOVA, there was no significant difference among the values of RSA measured by the three techniques (p > 0.05). The results of Wilcoxon matched-pairs signed-rank test further demonstrated that there was no significant difference among the values of RSA in both single- and multi-rooted teeth measured by the three techniques (p > 0.05).ConclusionsThe membrane technique, the 3D scanning technique, and CBCT reconstruction are novel reliable techniques for measuring the RSA in both single- and multi-rooted teeth, which will provide wide clinical applications in the future.     

Narrowing of the radicular pulp space in coronally restored teeth

Objectives

Narrowed radicular pulp spaces are frequently observed in teeth wearing extended restorations. The present study investigates whether the narrowing of particularly the radicular pulp space can be attributed to coronal restorations.

Materials and methods

The study is based on an anonymized copy of the cone-beam computed tomography (CBCT) database from the Center of Dental Medicine of the University of Zurich. One hundred CBCT scans were selected out of 7317 data sets to match either a crowned (group A; n = 50) or a filled tooth (group B; n = 50) with a contralateral healthy, unrestored, and caries-free control tooth at the same position, respectively. Cross-sectional images were adjusted in the coronal, middle, and apical root third of each subjected tooth. Screenshots were taken in that position and analyzed. The area occupied by the pulp space was determined as percentage area of the whole root diameter on each cross section. The resulting values were compared between restored and control teeth.

Results

In both groups (crowned and filled teeth) and in all the three root thirds, the radicular pulp space was significantly narrower in the restored teeth compared to the control teeth. The strongest narrowing effect was observed in the coronal root third and it decreased towards the apical root third (both groups).

Conclusions

Teeth with coronal restorations show within the limitations of the present study a significant narrowing of their radicular pulp space.

Clinical relevance

The asserted narrowing could have a complicating effect if root canal treatment becomes necessary in those teeth.

     

Computer-Controlled CO2 Laser Ablation System for Cone-beam Computed Tomography and Digital Image Guided Endodontic Access: A Pilot Study

IntroductionIdeal endodontic access provides unobstructed entry to the pulp chamber and visualization of the canal orifices while preserving the maximum amount of tooth structure. The aim of this study was to implement the use of lasers to accurately and predictably access teeth to follow the principles of minimally invasive endodontics.MethodsTraditional, conservative, ultraconservative, bridge, truss, and orifice-directed accesses were performed. A computer-controlled 9.3-μm CO₂ laser ablation system was assembled and coupled with custom software capable of combining cone-beam computed tomographic (CBCT) volumetric data with spatially calibrated digital images of teeth to provide an augmented reality environment for designing and preparing endodontic accesses. Twenty (N = 20) sound posterior teeth with fully developed root canal systems were imaged with CBCT scans and accessed via laser ablation in vitro.ResultsAll 20 (20/20) teeth were successfully accessed without iatrogenic errors. Volumetric renderings from post-access CBCT scans were used to verify the access and determine accuracy qualitatively. The volumetric measurements of hard tissue removed were as follows: traditional = 39.41 mm³, conservative = 9.76 mm³, ultraconservative = 7.1 mm³, bridge = 11.53 mm³, truss = 19.21 mm³, and orifice directed = 16.86 mm³.ConclusionsDigital image guidance based on feature recognition and registration with CBCT data is a viable method to address the challenge of dynamic navigation for accessing the pulp chamber. Modern lasers with high pulse repetition rates integrated with computer-controlled scanning systems are suitable for the efficient cutting of dental hard tissues.     

Comparing nanoleakage between class II bulkfill and incremental composite restorations using snowplow technique

PurposeTo compare the nanoleakage between bulkfill and incremental-fill resin composites in class II slot preparations for primary and permanent teeth restored by the snowplow technique.Materials and MethodsClass II slots were prepared in 32 M (16 exfoliated/extracted primary and 16 permanent molars). Optibond All-InOne self-etching adhesive was applied and cured. A flowable composite, Premise, was then injected into the gingival seat without curing using the snowplow technique. Cavities were restored using Sonicfill/bulkfill or microhybrid Herculite composites. Energy dispersive X-ray spectrometry was used to assess nanoleakage as silver deposition percentages along the axial and cervical walls. Multivariate analysis of variance was used to assess the effect of tooth type (primary and permanent teeth) and placement technique (bulkfill and incremental techniques) on nanoleakage at the axial and cervical walls.ResultsBulkfill restorations had significantly greater nanoleakage than incremental restorations at the cervical walls in primary and permanent molars (mean = 1.21 vs 0.49 in primary molars and 0.76 vs 0.24 in permanent molars). Equivalent results were observed at the axial walls of the restorations (mean = 0.66 vs 0.14 in primary molars and 0.28 vs 0.08 in permanent molars, with a P value of<0.001).ConclusionsLess nanoleakage was observed in class II slot/snowplow resin–composite restorations using the incremental technique compared to bulkfill in both dentitions. However, greater nanoleakage was detected on the cervical walls when compared with the axial walls.     

Influence of Minimally Invasive Access Cavity Designs on the Fracture Resistance of Endodontically Treated Mandibular Molars Subjected to Thermocycling and Dynamic Loading

IntroductionThe aim of this study was to investigate the fracture resistance of endodontically treated and restored permanent mandibular molars with minimally invasive access cavities subjected to thermocycling and dynamic loading.MethodsForty first and second mandibular molars were randomly assigned to 4 groups (n = 10/group) as follows: group 1, control (intact teeth); group 2, traditional access cavity (TradAC); group 3, conservative access cavity (ConsAC); and group 4, truss access cavity (TrecAC). After endodontic treatment, teeth were restored with SDR core (Dentsply Caulk, Milford, DE) and subjected to thermocycling followed by dynamic and static loading with a multiaxial fatigue testing machine (Instron, Canton, MA). The maximum load to fracture and pattern of failure (restorable/unrestorable) were recorded. Data were evaluated with analysis of variance and the Tukey post hoc test for multiple comparisons.ResultsFracture resistance of the samples in the control group were higher than those in the experimental groups (P < .005). TradAC exhibited the least resistance to fracture (P < .005). There was no statistically significant difference in the fracture resistance of ConsAC and TrecAC (P = .361) Unrestorable fractures were more frequent in the TradAC group compared with all other groups.ConclusionsMandibular molars with ConsAC and TrecAC exhibited superior fracture resistance compared with TradAC. TradAC had the highest number of unrestorable fractures.     

Accuracy of Different Imaging CBCT Systems for the Detection of Natural External Radicular Resorption Cavities: An Ex Vivo Study

ObjectiveThe aim of this study was to compare the sensitivity and specificity of 3 different systems of cone-beam computed tomography (CBCT) in the detection of natural external root resorption (ERR) cavities using microtomography as the gold standard.MethodA sample of 126 ex vivo teeth were submitted to a microtomography examination to verify the presence/absence of ERR cavities. Then, they were divided into the control group: 85 teeth that did not present with an ERR cavity; and experimental group: 41 teeth that presented with 1 or more ERR cavities. The size of the natural ERR cavities varied from 2.46 mm³ to 3.11 mm³, which corresponded to cavities of 1.67 mm and 1.81 mm in diameter, respectively. The teeth were placed on a dry human mandible for scanning in each of the 3 protocols with different voxel sizes: 0.25 mm, 0.20 mm, and 0.166 mm.ResultsThe accuracy of the 3 protocols evaluated in this study are listed in decreasing order: 60.3% for a voxel size of 0.20 mm, 56.7% for a voxel size of 0.166 mm, and 46.7% for a voxel size of 0.25 mm; these are smaller values than previous studies have obtained using artificial ERR cavities. Statistically significant results were not found among the 3 CBCT protocols that were used (P > .05), and the receiver operating characteristic curve shows the small differences found between the protocols.ConclusionThe results indicate that CBCT presents, for natural ERR, lower sensitivity and specificity values than those detected in previous studies of artificial cavities. The results demonstrate that natural ERR is neither easily observed nor accurately located by CBCT, as previous studies using artificial ERR indicated.     

In Vivo Strain Alterations in Mandibular Molars after Root Canal Treatment Procedures

IntroductionThe aim of this investigation was to determine the coronal strain variations in mandibular molars under an in vivo bite load after root canal treatment procedures.MethodsThe coronal strain in carious mandibular first molars with symptomatic irreversible pulpitis (experimental group) was compared with that of intact contralateral teeth (control group) in patients 20–40 years old. Experiments were conducted in 2 stages. In stage 1, the maximum bite force on the first molar region was determined on the experimental and control teeth using a customized load cell. In stage 2, strain gauges were bonded to the buccal aspect of teeth, and the strain was recorded after the application of a bite load on the intact (control) teeth; and the experimental teeth before and after endodontic access cavity preparation, cleaning/shaping procedures, root filling, and composite core restoration.ResultsThe mean maximum bite force on the experimental teeth (91 ± 48 N) and the contralateral control teeth (91 ± 49 N) was not significantly different (P = .989). The preoperative strain (microstrain) in the experimental teeth was significantly higher (125 ± 36, P = .001) than in the contralateral intact teeth (46 ± 17). Access cavity preparation significantly increased the strain (327 ± 98, P = .019) on the experimental teeth compared with the preoperative strain. Cleaning/shaping (355 ± 113) and root filling (346 ± 89) did not significantly increase (P = 1.00) the strain compared with the strain determined after endodontic cavity preparation. Composite core restoration in the experimental teeth (106 ± 41) resulted in a significant reduction in the strain compared with the values recorded after an endodontic access cavity (P = .002) and was similar to the preoperative strain values (P = 1.00) but was significantly higher than the strain values in contralateral intact teeth (P = .001).ConclusionsThe coronal strain on the buccal surface of mandibular first molars significantly increased with access cavity preparation, which did not increase further after cleaning/shaping or root filling. A significant reduction in the strain induced by root canal treatment steps was evident after composite core restoration.     

External root resorption of the second molar associated with mesially and horizontally impacted mandibular third molar: evidence from cone beam computed tomography

Objectives

The aim of the present study was to assess the incidence and risk factors of ERR in second molars with mesially and horizontally impacted mandibular third molars using cone beam computed tomography (CBCT) images from patients in a Chinese tertiary referral hospital.

Materials and methods

A total number of 216 patients with 362 mesially and horizontally impacted mandibular third molars who were treated at our institution from 2014 to 2015 was retrospectively included. The ERR in second molars was identified on CBCT multiplanar images. The associations between incidence of ERR and multiple clinical parameters were statistically analyzed by Chi-square test. Moreover, the risk factors for ERR in second molars were further assessed by multivariate regression analysis.

Results

The overall incidence of ERR in second molars was 20.17 % (73/362) as detected on CBCT images. The presence of ERR significantly associated with patients age and impaction depth of mandibular third molars. However, no significant relationship was found between ERR severity and impaction depth or ERR location. Multivariate regression analyses further revealed age over 35 years and impaction depth as important risk factors affecting the ERR incidence caused by mesial and horizontal impaction of mandibular third molar.

Conclusions

ERR in second molar resulted from mesially and horizontally impacted mandibular third molar is not very rare and can be reliably identified via CBCT scan.

Clinical relevance

Given the possibility of ERR associated with third molar impaction, the prophylactic removal of these impacted teeth could be considered especially for those patients with over 35 years and mesially and horizontally impacted teeth.

     

Cone-beam Computed Tomographic Scans in Comparison with Periapical Radiographs for Root Canal Length Measurement: An In Situ Study

Introduction

The primary aim of this study was to compare the precision of root canal length determination on cone-beam computed tomographic (CBCT) scans and periapical radiographs (PAs) with the actual root canal length. The secondary aim was to examine the influence of tooth type on root canal length measurements as assessed on CBCT scans and PAs.

Methods

In total, 40 root canals of 33 teeth (molars, premolars, canines, and incisors) out of 5 dentate maxillas of human cadavers were included. Root canal length measurement was performed by a consensus panel (2 examiners) on CBCT scans (3D Accuitomo 170; J Morita, Kyoto, Japan) and digital PAs. After straight-line access opening, a #15 file was fixated in every root canal at the length measured on CBCT scans. All teeth were extracted, and the root canal containing the file was uncovered. Measurements made on images taken with a digital camera (AxioCam; Carl Zeiss, Sliedrecht, The Netherlands) linked to a stereozoom microscope (Stemi SV6, Carl Zeiss) were used as the actual root canal length.

Results

When all roots were examined together, it was not clear which method is better for all types of teeth. For root canals of anterior teeth, there was no significant difference between the 2 methods. For root canals of posterior teeth, CBCT images gave results significantly closer to the actual root canal length in comparison with PAs (t value = −1.96; critical value is 1.74 with a significance level of 0.05).

Conclusions

Root canal length measurements of posterior maxillary teeth were more accurate when assessed by CBCT images than PAs.     

Three-dimensional Analysis of Alveolar Bone With and Without Periodontitis

ObjectiveThe aim of this study was to investigate the alveolar bone density and thickness in Chinese participants with and without periodontitis.MethodologyThis study was retrospective and cross-sectional in nature and used cone-beam computed tomography (CBCT) to evaluate alveolar bone loss, bone density, and bone thickness around 668 mandibular molars (344 periodontally healthy teeth and 324 teeth with periodontitis). Comparative statistical tests were done related to the age, sex, tooth type, tooth side, and degree of bone loss. The significance level was set to be P < .05.ResultsThe alveolar bone density significantly differed between the healthy and periodontitis groups (mean difference = 24.4 Hounsfield units; P = .007). Similarly, the alveolar bone thickness of the healthy group was significantly higher than that of the periodontitis group (4.6 ± 1.8 mm compared to 4.2 ± 1.1 mm). Teeth in females demonstrated a significantly (P ? .001) higher bone density compared with males in both healthy and compromised groups. However, males showed a significantly (P ? .05) thicker bone of the teeth than females in relation to the healthy group. The alveolar bone density and thickness in both healthy and periodontitis groups significantly differed between the first and the second molars (P < .001). The alveolar bone thickness had a highly significant difference (P < .001) between the different degrees of bone loss.ConclusionsAlveolar bone thickness and density were reduced at periodontally diseased teeth.     

Comparison of the Effects of WaveOne Gold,TruNatomy, and Conventional Hand Files on Remaining Dentin Volume in the Coronal Part of the Root and Preparation Efficiency in Mandibular Molars

IntroductionThe use of file systems that work with different principles in root canal treatment is becoming widespread. The aim of this study was to evaluate the remaining dentine volume in the coronal region of the root and preparation efficiency after the use of conventional hand files, WaveOne Gold; which works with reciprocating motion, and TruNatomy; which works with rotational motion in the root canal treatment of mandibular molar teeth.MethodsAll canals of permanent mandibular molars (n = 36) were used. Root canals in each group (n = 12) were prepared with conventional hand files, WaveOne Gold, and TruNatomy. The three-dimensional images were evaluated for remaining dentine volume in the coronal two-millimeter region of the root and change in volume of the entire root canal space.ResultsThere was no statistically significant difference between the groups in terms of mean differences pre and postpreparation (P > .05). The mean differences after preparation were observed the most in the WaveOne Gold group and the least in the TruNatomy group in the coronal two-millimeter region of the root and entire canal volume, but the differences were not significant (P > .05, P > .05, respectively).ConclusionsConventional hand files, WaveOne Gold working with reciprocating motion, and TruNatomy working with rotational motion, which are the file systems used in the study, are not superior to each other in terms of remaining dentin volume in the coronal two-millimeter region of the root and preparation efficiency in the entire root canal space in mandibular molars.     

Clinical Factors Associated with Apical Periodontitis Visible on Cone-beam Computed Tomography but Missed with Periapical Radiographs: A Retrospective Clinical Study

IntroductionCone-beam computed tomographic (CBCT) imaging is useful in detecting apical periodontitis, which is often missed in periapical (PA) radiographs. This study aimed to identify preoperative predictors correlated with the presence of apical periodontitis visible only in CBCT images and to investigate the important characteristics of such lesions.MethodsIn total, 332 consecutive patients with both PA radiographs and CBCT images were enrolled in this study. The patients’ clinical charts were reviewed retrospectively to collect information regarding their symptoms and diagnoses. Periapical lesions were assessed using a modified CBCT PA index by 2 endodontists. Patient-related factors (age, sex, and symptoms) and tooth-related factors (tooth type, location, pulp status, and pulpal diagnosis) were assessed to determine their relationships with the presence of apical periodontitis visible only in CBCT images.ResultsApical periodontitis was detected in 24.6% and 35.5% of untreated teeth by PA radiographs and CBCT images, respectively. In a multivariate logistic regression analysis, pulp necrosis was significantly correlated with the presence of apical periodontitis visible only in CBCT images (odds ratio = 5.401; 95% confidence interval, 1.911–15.265; P = .001); the involvement of molars showed borderline nonsignificant correlation (odds ratio = 2.843; 95% confidence interval, 0.990–8.164; P = .052). Lesion sizes smaller than 2 mm in diameter and the involvement of molars were significant factors of lesions visible only in CBCT images (P < .05).ConclusionsPulp necrosis was a preoperative predictor of apical periodontitis visible only in CBCT images. This research could provide a proper indication for CBCT imaging at diagnostic stages.     

Prevalence and Characteristics of Root Resorption Identified in Cone-Beam Computed Tomography Scans

IntroductionRoot resorption is a destructive process that compromises tooth structure and can result in tooth loss. Often it remains asymptomatic and is an incidental finding on radiographic examinations. The purpose of this study was to determine prevalence and characteristics of root resorption in patients referred for cone-beam computed tomography (CBCT) imaging for a variety of indications.MethodsThe study included CBCT scans of 1086 consecutive patients referred for CBCT imaging over an 18-month period. A total of 1148 scans were acquired. Data were abstracted from radiology reports, and prevalence estimates of resorption were computed for the aggregate sample and also across specific indications.ResultsResorption was identified in 171 patients (15.7%, 95% CI: 13.6%–17.9%) and in 249 teeth with a prevalence range of 2.6%–92.3% across specific indications. An 18.7% of the patients had 2 resorption sites whereas 8.8% had 3 or more resorption sites. The majority of affected teeth were anteriors (43.8%), followed by molars (40.6%) and premolars (14.5%). The most prevalent resorption types were external (29.3%), cervical (22.5%), infection-induced apical resorption (13.7%), internal (9.6%), and impacted tooth induced (8.8%). The majority of teeth with resorption did not have prior endodontic treatment (73.9%) and had radiographically normal periapex (69.5%). Of 249 teeth with resorption, 31% presented as incidental finding. The prevalence of incidental findings of resorption increased with age, P < .05, and was significantly lower for anterior teeth (20.2%) as compared to premolars (41.7%) and molars (36.6%), (P < .05).ConclusionThe high proportion of incidental findings of resorption detected by CBCT suggests that resorption is not recognized/detected by conventional radiography and therefore remains underdiagnosed.     

Guided Endodontics: Volume of Dental Tissue Removed by Guided Access Cavity Preparation—An Ex Vivo Study

IntroductionGuided endodontics emerged as an alternative method capable of providing greater precision and accuracy to endodontic treatments. The aim of the present study was to compare the volume of dental tissue removed after guided endodontic access (GEA) and conventional endodontic access (CEA) to mandibular incisors and upper molars.MethodsTwenty extracted human mandibular incisors and upper molars were selected and submitted to cone-beam computed tomographic (CBCT) examination. They were divided into 2 groups, G1 (mandibular incisors) and G2 (maxillary molars), and subdivided into G1a (CEA), G1b (GEA), G2a (CEA), and G2b (GEA). The Digital Imaging and Communications in Medicine files obtained by examining the CBCT scans were transferred to InVesalius software (Renato Archer Information Technology Center, Campinas, SP, Brazil) to calculate the initial volume of each tooth. G1b and G2b teeth were scanned with a device to plan and print the guides. After gaining endodontic access, new CBCT examinations were performed to calculate the final volume of each sample unit. The Student t test for independent samples compared the volumes among the groups.ResultsG1 group had an average volume reduction of 31.667 mm³ (10.62%) using CEA and 26.523 mm³ (10.65%) using GEA with no significant difference among the groups (P = .960). There was an average volume reduction of 62.526 mm³ (5.86%) in the G2 group using CEA and 45.677 mm³ (4.11%) using GEA with a significant difference among the groups (P = .004).ConclusionsGEA preserved a greater volume of dental tissue in extracted upper human molars than CEA; however, there was no significant difference between CEA and GEA in the volume of dental tissue removed from mandibular incisors.     

A temporary filling material during endodontic treatment may cause tooth fractures in two-surface class II cavities in vitro

Objectives

To investigate the effect of a zinc oxide/zinc sulphate-based cement as a temporary filling material during root canal treatment on the occurrence of cracks within the filling material or the tooth.

Materials and methods

Root canals of 122 extracted human molars were prepared using ProTaper instruments. Standardized occlusal-distal cavities were prepared. After placing calcium hydroxide into the root canals, the teeth were divided randomly into four groups containing 33 specimens each. In the Coltosol group, the cavity was completely filled with Coltosol® F. In the Coltosol-Clearfil group, a 2-mm layer of Coltosol® F was placed into the apical part of the pulp chamber, and in the Clearfil group, a foam pellet was placed into the coronal pulp chamber. The remaining cavities were filled with Clearfil™. In the control group, the cavities were not restored. The teeth were stored at 37 °C for 14 days and examined every 24 h under a stereomicroscope.

Results

Fractures of the filling and/or the tooth were only observed in the Coltosol group. All Coltosol® F restorations had cracks after 24 h. Tooth fractures were found in 25 (76 %) teeth. Among these teeth, 21 (84 %) had crown fractures, four (16 %) had root-crown fractures. All root-crown fractures were vertical.

Conclusion

Coltosol® F when used alone led to tooth fractures in two-surface class II cavities in teeth undergoing root canal treatment.

Clinical relevance

Coltosol® F solely used as restorative material may lead to tooth fractures in two-surface class II cavities.