Vertical Root Research Articles

In vitro diagnostic accuracy of cone-beam computed tomography with variable gamma values for detection of vertical root fractures in teeth with prefabricated metal posts.

Background:Cone-beam computed tomography (CBCT) has the highest sensitivity and specificity for the detection of vertical root fractures (VRFs). This study aimed to compare the diagnostic accuracy of CBCT with different gamma values for the detection of VRFs.Materials and Methods:In this in vitro, experimental study, multiplanar CBCT scans were obtained from 61 extracted premolars with prefabricated titanium posts using NewTom CBCT scanner. Next, VRFs were artificially induced in all teeth with a mallet, and the teeth underwent CBCT with three different gamma values. The images were evaluated by two observers twice with a 2-week interval for the presence/absence of VRFs. Data were analyzed using the kappa coefficient, McNemar test, and Chi-square test. The sensitivity, specificity, and overall accuracy of CBCT with different gamma values for the detection of VRFs were assessed by receiver operating characteristic curve. The level of significance was lesser than 0.05 (P < 0.05).Results:Changing the gamma value did not change the sensitivity, specificity, or accuracy of CBCT for the detection of VRFs. No significant difference was noted between the two observers in the detection of VRFs on CBCT scans taken with different gamma grades. The inter- and intra-observer agreement were excellent for all gamma grades.Conclusion:Any gamma value preferred by the observer can be used for the detection of VRFs on CBCT scans.

Early diagnosis of vertical root fracture

Early diagnosis of vertical root fracture

Prevention of vertical root fracture and improvement of sealing ability by adhesive root canal filling

Prevention of vertical root fracture and improvement of sealing ability by adhesive root canal filling

Outcomes of endodontic microsurgery with retrofilling of calcium silicate cements with or without calcium chloride accelerator: A randomized controlled clinical trial

Introduction: Calcium silicate-based cement (CSC) with calcium chloride (CaCl2) accelerator sets faster than the cement without accelerator. For endodontic microsurgery, CSC with the accelerator tends to be less soluble in tissue fluid that may improve clinical outcome. This study aimed to evaluate the outcome of endodontic microsurgery by retrofilling with CSC containing accelerator (Bio-MA) compared to the original CSC (ProRoot® mineral trioxide aggregate [MTA]).Materials and Methods: Forty-eight teeth required surgical root canal retreatment was included according to the eligible criteria. Endodontic microsurgery with standardized protocol was performed under the dental operating microscope. Bio-MA or ProRoot® MTA was randomly selected for retrofilling. At recall visit, treatment outcomes were evaluated as “healed,” “healing” or “diseased,” based on clinical and radiographic assessments. The Chi-square test and Fisher's exact test were used in the statistical analysis of the outcome.Results: Seven teeth were excluded because of vertical root fracture detected in surgery (n = 5) and inadequate retrofilling depth (n = 2). Two cases were lost to follow-up. For thirty-nine teeth with 14.9 ± 5.2 months recall, “healed” rates were 85% in Bio-MA and 84.2% in ProRoot® MTA, and “healing” rates was 15% in Bio-MA and 15.8% in ProRoot® MTA. None of “disease” was observed. No significant difference in the clinical outcome was observed between groups of Bio-MA and ProRoot® MTA (P = 1.00).Conclusions: The endodontic microsurgery outcome of Bio-MA containing CaCl2 accelerator was similar to that of ProRoot® MTA without accelerator.

Micro-computed tomography assessment of dentinal microcracks after the preparation of curved root canals with rotary and reciprocal systems.

Root canal preparation with nickel-titanium (NiTi) instruments may lead to the formation of microcracks in the root canal wall. Vertical root fractures may initiate from dentinal cracks, and eventually necessitate tooth extraction. This study aimed to assess the effect of the instrumentation of curved root canals of mandibular molars with the 2Shape (2S) sequential rotary, EdgeFile® X1 (EFX1) reciprocating and NeoNiTi (NN) rotational single-file systems on the formation of dentinal microcracks with the use of micro-computed tomography (micro-CT). Thirty curved mandibular molar root canals were instrumented with the 2S, EFX1 and NN systems (10 in each group). The teeth underwent micro-CT before and after instrumentation. Next, the pre-instrumentation and post-instrumentation cross-sectional images were evaluated and compared for the detection of dentinal microcracks. The number of microcracks in each group was calculated and reported as percentage. The data was analyzed using the McNemar's test with the IBM SPSS Statistics for Windows software, v. 25.0 (α = 0.05). Out of the 29,280 cross-sectional images evaluated in this study, 11.5% showed dentinal microcracks (n = 3,362). On the post-instrumentation images, the frequency percentage of microcracks was 12.0% (n = 585) in the 2S group, 8.8% (n = 402) in the EFX1 group and 13.3% (n = 694) in the NN group. All of the microcracks detected on the post-instrumentation images were also present on the preinstrumentation images and no new microcracks were formed after root canal instrumentation with the aforementioned systems. Root canal instrumentation with the 2S, EFX1 and NN systems did not result in the formation of new dentinal microcracks.

Clinical Considerations in Orthodontically Forced Eruption for Restorative Purposes.

For restorations on teeth involving invasion of the supracrestal tissue attachment (biological width), as well as for lack of ferrule effect, crown lengthening is required for long-term periodontal health and success of the restoration. In the same fashion, site development is often necessary prior to implant placement in order to provide optimal peri-implant soft and hard tissue architecture conducive to future esthetics and function. Orthodontic extrusion, also known as forced eruption, has been developed and employed clinically to serve the purposes of increasing the clinical crown length, correcting the periodontal defect, and developing the implant site. In order to provide comprehensive guidance on the clinical usage of this technique and maximize the outcome for patients who receive the dental restoration, the currently available literatures were summarized and discussed in the current review. Compared to traditional crown lengthening surgery, forced eruption holds advantages of preserving supporting bone, providing improved esthetics, limiting the involvement of adjacent teeth, and decreasing the negative impact on crown-to-root ratio compared to the traditional resective approach. As a non-invasive and natural technique capable of increasing the available volume of bone and soft tissue, forced eruption is also an attractive and promising option for implant site development. Both fixed and removable appliances can be used to achieve the desired extrusion, but patient compliance is a primary limiting factor for the utilization of removable appliances. In summary, forced eruption is a valuable treatment adjunct for patients requiring crown lengthening or implant restorations. Nonetheless, comprehensive evaluation and treatment planning are required for appropriate case selection based upon the known indications and contraindications for each purpose; major contraindications include inflammation, ankylosis, hypercementosis, vertical root fracture, and root proximity. Further studies are necessary to elucidate the long-term stability of orthodontically extruded teeth and the supporting bone and soft tissue that followed them.

Vertical Root Fracture in Non-Endodontically and Endodontically Treated Teeth: Current Understanding and Future Challenge.

A vertical root fracture (VRF) is a complex complication that usually leads to tooth extraction. The aim of this article is to review the prevalence, demography, distribution, diagnostic methods, etiology and predisposing factors, clinical features, radiographic characteristics and treatment strategies of VRFs in non-endodontically treated teeth (VRFNETT) and endodontically treated teeth (VRFETT). Search terms for each subject related to VRFNETT and VRFETT were entered into MEDLINE, PubMed and Google Scholar. Systematic reviews, retrospective cohort studies, demographic research, clinical studies, case reports and case series were reviewed. Most of the VRFs were found in patients older than 40 years old. Older populations were discovered in the non-endodontically treated VRF group when compared to the endodontically treated VRF group. Male patients were found at a greater prevalence than females in the non-endodontically treated VRF group. The initial occurrence of a VRF may accompany radiolucent lines within the root canal, unusual space between the canal wall and intracanal material, a widening of the PDL space along the periradicular surfaces, angular bony destruction, step-like bone defects, V-shaped diffuse bone defects, or root resorptions corresponding to the fracture line before the clear separation of the fractured fragment. The indicative clinical and radiographic signs of VRF included a coronally positioned sinus tract, deep-narrow periodontal defects, the displacement of a fractured fragment, periradicular radiolucent halos and the widening of the root canal space. Interestingly, VRFNETT are more often observed in the Chinese population. Some patients with multiple VRFs were observed, suggesting possible predisposing factors in genetics and tooth development. The management of a VRF usually involves a multidisciplinary approach. The common distribution and features of VRFNETT and VRFETT were elucidated to facilitate recognition and diagnosis. Besides extraction, variable therapeutic schemes, such as the repair of the VRF, root amputation and others reported in earlier literature, are available. A long-term prognosis study of the various therapeutic strategies is needed.

Increased Trailing Limb Angle is Associated with Regular and Stable Trunk Movements in Patients with Hemiplegia

ObjectivesIn post-stroke patients, shifts in the center of gravity may affect joint movement patterns of the paraplegic lower limb during walking. The impact of changes in ankle dorsiflexion angle and trailing limb angle due to slight weight-shifting is unknown. This study aimed to investigate the effect of the abovementioned parameters on gait characteristics measured by trunk acceleration. Materials and methodsDuring walking, the ankle dorsiflexion angle and trailing limb angle were assessed using two-dimensional motion analysis. Shifts in the center of gravity were assessed to evaluate symmetry, regularity, and sway of trunk movements by calculating the harmonic ratio, autocorrelation coefficient, and root mean square using a wearable trunk accelerometer. ResultsAnkle dorsiflexion angle showed a significant negative correlation with the root mean square of the anteroposterior axis (r = -0.460, p = 0.005). Trailing limb angle was significantly correlated with the autocorrelation coefficient of the vertical axis (r = 0.585, p < 0.001) and root mean square of the vertical (r = -0.579, p < 0.001), mediolateral (r = -0.474, p = 0.004), and anteroposterior axes (r = -0.548, p = 0.001). Trailing limb angle was a significant predictor (autocorrelation coefficient vertical axis, p = 0.001; root mean square vertical axis, p = 0.001; mediolateral axis, p = 0.007; anteroposterior axis, p = 0.001). ConclusionsTrailing limb angle can indicate the acquisition of forward propulsion during walking; an increase in it may contribute to improvements of the regular vertical movement ability and stability of the center of gravity sway.

Cone Beam Tomography and Periapical Radiographs for Early Vertical Root Fracture Diagnosis. Systematic Review

Background: Determining the position, direction, and size of the fracture in early stages is of great value in choosing the appropriate treatment. Purpose: To compare the diagnostic accuracy of conventional periapical radiographs (PR) with cone beam computerized tomography (CBCT) to identify vertical root fractures (VRF) in root treated teeth. Methods: This review used the Cochrane Handbook and the recommendations given by SIGN 50 as a guide. Meta DiSc 1.4 software was used to calculate the operative characteristics of sensitivity, specificity, positive, and negative values. Results: Initially 651 articles were obtained; after completing the review 4 articles were chosen: 2 studies had a sensitivity of 60-61 % using conventional PR and 80 % CBCT; specificity 70-71 % using conventional RP and 69 % CBCT; there were no significant differences between the two (p &gt;0.05). Digital dental radiography (DDR) had a specificity of 78 % compared to 70 % of the conventional RP. Conclusions: Based on the results and the information published, both tools, digital dental radiograph (DDR) and CBCT are useful to diagnose VRF. There were no significant differences between the CBCT and conventional (PR) (p &gt;0.05) either in advanced or early stages of VRF. To answer research the question more studies are required. To make an early VRF diagnosis on initial stages, the current imaging tools, clinical methods, and patient's symptoms must be considered. As a final option, a surgical exploration is required to confirm its presence.

Outcome of Endodontic Treatment through Existing Full Coverage Restorations: An Endodontic Practice Case Series

IntroductionThis case series assessed the outcome of nonsurgical endodontic treatment completed through retained full coverage restorations (FCRs) in a board-certified endodontist private practice. The number of cases completed by the first author was 153. MethodsAll cases were performed following a standardized protocol for treatment and restoration depending on the type of FCR. Number of cases that showed up for 2- to 4-year follow-up was 127, with 83% recall rate. The age range of patients was 33–95 years, with mean age of 54.734 years. The mean recall time was 2.448 years. FCRs and their distribution were as follows: 4 anterior teeth, 14 premolars, and 109 molars. There were 103 nonsurgical root canal treatments and 24 retreatments. Patients who presented for recall had 74 porcelain fused to metal crowns, 17 zirconia crowns, 15 abutments of porcelain fused to metal bridges, 14 lithium disilicate crowns, 5 gold crowns, 1 full metal crown, and 1 gold onlay. ResultsThere were no endodontically related failures. Six cases failed; 3 were due to vertical root fractures, 1 was due to horizontal root fracture, and 2 were due to extensive recurrent caries causing restorative failure. The percentage of healed cases following the American Association of Endodontists outcome criteria adopted in 2004 with intact retained FCR was 95.3%. ConclusionsThe results suggest predictable favorable outcomes for nonsurgical endodontic treatment through FCR following the proposed protocol for diagnosis, treatment, and restoration.

A critical analysis of research methods and experimental models to study dentinal microcracks.

The purpose of this narrative review was to discuss the scientific milestones that led to the current understanding of the root dentinal microcrack phenomenon based on the interplay between the usage of micro-computed tomography (micro-CT) as an analytical tool alongside a close-to-mouth experimental model. In 2009, reports on the development of dentinal microcracks in extracted teeth after root canal preparation triggered an awareness of the potential for vertical root fractures (VRFs) of endodontically treated teeth could be developed from defects created by the mechanical stress of nickel-titanium preparation systems on dentine. This assumption was taken for granted, even though no cause-effect relationship had been scientifically demonstrated. Since then, several studies using the sectioning method with extracted teeth have been published and the large discrepancy amongst their outcomes soon become evident. Moreover, the high frequency of reported dentinal microcracks largely contrasted with the clinical incidence of VRFs, raising doubts on their methodological reliability. Using micro-CT technology, it was demonstrated by several studies that, in extracted teeth, dentinal defects already existed before the endodontic procedures, indicating that the initial reports framed a non-existing cause-effect relationship between canal preparation and dentinal microcracks. Although these new findings contributed to a better comprehension of this phenomenon, the misconception that microcracks were the starting point for VRFs was only surpassed with a new in situ approach using fresh cadavers. Surprisingly, microcracks were not identified in sound teeth. As a conclusion, dentinal microcracks in extracted teeth can be considered a non-natural occurrence observed only in a laboratory set-up as a consequence of dehydration and storage conditions. Thus, dentinal microcracks shall not be considered as the starting point for VRFs as they do not manifest in non-extracted teeth. Identifying dentinal microcracks as a laboratory phenomenon highlights the impact of recent scientific developments to disclaim the clinical relevance of laboratory-obtained outcomes.

Pathognomonic Combination of Clinical Signs for Diagnosis of Vertical Root Fracture: Systematic Review of the Literature

Introduction: Vertical root fracture (VRF) is a root-canal treatment complication and is a major reason for extraction of the root-canal-treated teeth. The diagnosis of VRF can be complicated because of absence of specific signs, symptoms, and radiographic features. A combination that includes the presence of deep pocket and a sinus tract in root-canal-treated tooth was proposed as a pathognomonic for VRF. The purpose of this study was to systematically search and evaluate the literature regarding the correlation between the clinical signs considered pathognomonic for the diagnosis of VRF, with the actual reference standard by means of systematic review of the literature. Methods: A systematic search of the literature was performed to identify studies evaluating the clinical signs considered pathognomonic for the diagnosis of VRF. The following databases were searched: Medline (PubMed), Scopus, and Cochrane Central. The identified studies were subjected to strict inclusion and exclusion criteria. Results: Initially, 1141 possible relevant articles were identified. After title and abstract screening, 40 articles were subjected to a full-text evaluation, 3 articles met the inclusion criteria and contained data regarding the prevalence of the pathognomonic combination in VRF’s-confirmed teeth. The presence of deep pocket and a sinus tract in endodontically treated teeth was found in 28% of the cases. Conclusion: To date, the current scientific knowledge regarding the correlation between the clinical symptoms considered pathognomonic for VRF diagnosis in the root-canal-treated tooth and the actual reference standard is quite low.

Effects of residual film on maize root distribution, yield and water use efficiency in Northwest China

With the extensive use of plastic film, a large number of residual film accumulated in the farmland, bringing a huge negative impact on agricultural production. Studying the effect of residual film on roots is helpful to understand the damage mechanism of residual film on crop growth. Thus, a two-year field experiment was conducted with 0 (M0), 90 (M90), 180 (M180), 360 (M360), and 720 (M720) kg ha−1 residual film, and sine and logistic functions were used to simulate root growth and vertical distribution of maize. Results showed that root length decreased with residual film increasing and was more sensitive to residual film at tasseling, filling and maturity stages than at seedling and jointing stages. The results of the sine function fitting the total root length showed that the potential maximum root length was decreased and the rooting time was delayed, and the root growth time was shortened with the amount of residual film increasing. M90 had no significant effect on root length but residual film equal to or greater than 180 kg ha−1 had significant negative effects on root length. M180, M360 and M720 significantly reduced the actual total root length by 13.7%, 23.8% and 33.3%, and reduced the potential root length by 9.4%, 17.1% and 21.8%. M360 and M720 significantly shortened the growth time by 3.8% and 6.6%. The logistic function fit the vertical root distribution well. Residual film decreased the root length in deep soil and gathered roots in the soil layer near the depth of d50 at which 50% of the root length was accumulated. Residual film decreased the soil depth where 50% and 95% root length were accumulated and increased the proportion of root length in 0–30 cm soil layer. This adverse effect increased with residual film amount increasing. The dry matter of stems, leaves and ears decreased with residual film increasing. M90 reduced the above-ground dry matter insignificantly and the other treatments with residual film had significant effects. At the maturity stage, the above-ground dry matter in M90, M180, M360 and M720 was reduced by 2.4%, 14.2%, 22.2% and 29.4%, compared with M0. Residual film decreased evapotranspiration (ET), grain yield and water use efficiency (WUE) significantly except M90. ET, yield and WUE were reduced by 1.7%, 3.0% and 1.1% in M90, and 2.5%, 17.1% and 16.1% in M180, and 6.2%, 27.1% and 23.4% in M360, and 8.5%, 34.7% and 30.8% in M720, respectively. In summary, the residual film beyond 180 kg ha−1 had a significant negative effect on summer maize. This information will be useful to better understand and respond to residual film pollution and ensure safe agricultural production.

Six-Month Outcomes of Clinically Relevant Meniscal Injury in a Large-Animal Model.

Background:The corrective procedures for meniscal injury are dependent on tear type, severity, and location. Vertical longitudinal tears are common in young and active individuals, but their natural progression and impact on osteoarthritis (OA) development are not known. Root tears are challenging and they often indicate poor outcomes, although the timing and mechanisms of initiation of joint dysfunction are poorly understood, particularly in large-animal and human models.Purpose/Hypothesis:In this study, vertical longitudinal and root tears were made in a large-animal model to determine the progression of joint-wide dysfunction. We hypothesized that OA onset and progression would depend on the extent of injury-based load disruption in the tissue, such that root tears would cause earlier and more severe changes to the joint.Study Design:Controlled laboratory study.Methods:Sham surgeries and procedures to create either vertical longitudinal or root tears were performed in juvenile Yucatan mini pigs through randomized and bilateral arthroscopic procedures. Animals were sacrificed at 1, 3, or 6 months after injury and assessed at the joint and tissue level for evidence of OA. Functional measures of joint load transfer, cartilage indentation mechanics, and meniscal tensile properties were performed, as well as histological evaluation of the cartilage, meniscus, and synovium.Results:Outcomes suggested a progressive and sustained degeneration of the knee joint and meniscus after root tear, as evidenced by histological analysis of the cartilage and meniscus. This occurred in spite of spontaneous reattachment of the root, suggesting that this reattachment did not fully restore the function of the native attachment. In contrast, the vertical longitudinal tear did not cause significant changes to the joint, with only mild differences compared with sham surgery at the 6-month time point.Conclusion:Given that the root tear, which severs circumferential connectivity and load transfer, caused more intense OA compared with the circumferentially stable vertical longitudinal tear, our findings suggest that without timely and mechanically competent fixation, root tears may cause irreversible joint damage.Clinical Relevance:More generally, this new model can serve as a test bed for experimental surgical, scaffold-based, and small molecule–driven interventions after injury to prevent OA progression.

Effect of rotary systems and root canal preparation and dentin crack formation

Evidence indicates that root canal preparation is a critical step upon which the prognosis of the endodontic treatment depends. Vertical root fractures can furtherly develop as propagations from the previously formed dentin cracks. Therefore, root canal preparation should be carefully approached with the minimal crack formation and careful dentin removal. Different modalities have been proposed in the literature and rotary systems are most commonly used nowadays. Although the reported efficacy of these modalities is high, evidence shows that they are usually associated with a considerable risk of crack formation. In the present literature review, we have discussed the effects of rotary instrumentation and root canal preparation on dentinal crack formation based on evidence from the different studies in the literature. Our evidence showed that all of the investigated approaches to prepare root canals adequately can result in crack formation. The different rotary instrumentations also showed variable frequencies of developing dentinal cracks, and evidence from some comparative investigations shows that ProTaper modalities are associated with the least frequencies of the events. However, to make a solid conclusion for clinical practice, further research is still needed to validate our current evidence.

Effects of Slope Aspect and Rainfall on Belowground Deep Fine Root Traits and Aboveground Tree Height.

The vertical root distribution and rooting depth are the main belowground plant functional traits used to indicate drought resistance in arid and semiarid regions. The effects of the slope aspect on the aboveground traits are visible but not the belowground deep root traits. We aimed to investigate the fine root traits of the locust tree (Robinia pseudoacacia L.) planted on southerly and northerly aspects, and the variations in the rooting depth in regions with different rainfall, as well as assessing how deep rooting, might affect the response to drought in a loess region. We selected three study sites with different rainfall amounts, with six sampling plots at each site (three each with southerly and northerly aspects). Soil core samples were collected down to the depth where no roots were present. The locust trees tended to develop deeper fine roots rather than greater heights. The tree height and diameter were greater for locust trees on northerly aspects, whereas trees on southerly aspects had significantly deeper rooting depths. Fine root traits (root length, root area, and root dry weight density) were higher in the southerly aspect for both Changwu and Ansai, but lower in Suide. The ratio of the root front depth tree height ranged from 1.04 to 3.17, which was higher on southerly than northerly aspects, and it increased as the rainfall decreased. Locust tree growth traits (belowground fine root and aboveground tree height) were positively correlated with the mean annual rainfall. The soil moisture content of the topsoil decreased as the rainfall decreased, but the pattern varied in the deep layer. Our results suggest that the variations in the belowground rooting depth under different slope aspects may be related to plant survival strategies. The vertical extension of the rooting depth and tree height may be key functional traits that determine plant growth in drought-prone regions.

Accuracy of cone-beam CT in detecting vertical root fractures in teeth with post-endodontic restorations: an in vitro study

The aim of this study was to evaluate the accuracy of cone-beam CT (CBCT) for the detection of artificially created vertical root fractures (VRF) in extracted teeth restored with metallic (MP) and fiberglass (FGP) posts. After root canal obturation, 60 extracted human premolars were scanned by using the highest-resolution settings of a CBCT unit. The prepared roots were randomly divided into three groups: group C (control group): non-restored and non- endodontically treated teeth (n = 20); group MP (n = 20); group FGP (n = 20). In all groups, 10 teeth were artificially fractured. Two external and independent observers blindly recorded the presence or absence of VRF. Sensitivity, specificity, accuracy, intra- and interobserver agreement were calculated. Kappa value for inter- and intraobserver agreement was 0.82 and 0.84 respectively, demonstrating good agreement. The highest values for sensitivity (0.80 - 0.90), specificity (1.00) and accuracy (0.90 - 0.95) were found in the control group. The teeth with FGP restoration presented the lowest sensitivity (0.30 - 0.50) and accuracy (0.60 - 0.65) values. Both examiners had a good performance in the diagnosis of fractures in teeth with MP, with accuracy ranging between 0.85 - 0.90. The presence of MP did not influence accuracy; however, the presence of FGP reduced the diagnostic capacity of CBCT.

The Lower Cretaceous “Continental Intercalaire” around Tidikelt (Central Sahara, Algeria): Sedimentology, palaeontology and ichnology

The Lower Cretaceous strata are exposed over a large surface in the northern part of the Ahnet basin. They consist of transgressive, horizontal formations overlying the folded Palaeozoic formations by angular unconformity across the Tidikelt region. The present study addresses the respective lithostratigraphical units of the “Continental Intercalaire” succession and their subsequent palaeo-environment in the Tidikelt area using a trace fossil analysis combined with sedimentological and palaeontologic data. The lithological and sedimentological features of the study sections recognised eleven sub-units organised within four lithological units: the Lower Clay Unit of Barremian-Neocomian age consisting of three Sub-units (Akablie Sandstone, Sidi Mahmoud Clays and Pebbly Sands); the Quartzite Sandstones Unit referred to a Late Barremian-Early Aptian age; the Middle Clay-Sandstone Unit consisting of a thick deposit of Early Aptian-Albian age, divided into five Sub-units (Tit Sandstones, In Salah Sand-Clay, In Salah Sandstone, Foum El Bouib Sandstone, and Sandstone-Clay); and the Upper Clay Unit comprising the Oued Taleh Sand and the El-Golea Clays Sub-units. Vertebrate remains all evidence a Late Albian-Early Cenomanian age for the top part of the Continental Intercalary. Ichnologic data analysis documents lower diversity of the invertebrate trace fossils: only ten ichnotaxa are recorded so far and grouped in five ichnoassemblages. Fuvial-lacustrine ichnoassemblage represents a continental ichnofacies of a fluvial-lacustrine environment: Mermia, Scoyenia and Skolithos ichnofacies. Fluvial Ichnoassemblage of the Quartzite Sandstone Unit is represented by insect trace fossils typical of the Coprinisphaera ichnofacies. Fluvio-marginal ichnoassemblage corresponds to a tidal-influenced, fluvial deposit transgressive on Unit B, represented by Skolithos and Psilonichnus ichnofacies. Lower shoreface ichnoassemblage shows the upper part of Unit C, documented by horizontal trace fossils such as Thalassinoides and vertical root traces, all supporting a lower shoreface environment in a semi-arid climate interlined by well-oxygenated episode with nutrient-rich conditions and vegetation dominance. Near to shoreface ichnoassemblage coincides with the upper unit D of coastal deposits with fluvial-tidal influence at the base (Oued Taleh Sands) associated with Scoyenia and Skolithos trace fossils and lagoon deposit of the El-Golea Clays Sub-units.

Digital file format does not influence the radiographic diagnosis of vertical root fracture.

ObjectiveTo evaluate the influence of the file format of digital periapical radiographs on the diagnosis of vertical root fracture (VRF).Study designPeriapical radiographic images of 34 single-rooted teeth—19 with VRF, and 15 without VRF were acquired using two digital systems—Digora Toto, and Digora Optime, and exported into four different file formats—TIFF, BMP, PNG, and JPEG, totaling 272 radiographs. The radiographs were assessed by five examiners for the detection of VRF, using a 5-point scale (1—definitely absent; 2—probably absent; 3—uncertain; 4—probably present; 5—definitely present). Diagnostic values of area under the ROC curve, specificity, and sensitivity for the diagnosis of VRF were calculated. The results were compared by two-way Analysis of Variance with post hoc Tukey’s test. The intra- and inter-examiner agreements were measured by the Kappa test. The significance level was set at 5% for all analyses.ResultsThe values of intra-examiner agreement varied from moderate (0.56) to almost perfect (0.81), while the values of inter-examiner agreement varied from fair (0.29) to moderate (0.60). The image file format did not influence the diagnostic values for VRF for any of the radiographic systems tested (p > 0.05). Digora Toto had significantly greater values of area under the ROC curve than Digora Optime for all file formats (p = 0.001).ConclusionThe image file format of periapical radiographs does not influence the diagnosis of VRF, regardless of the digital radiography system.

Clinical analysis on the root fracture of the maxillary first molar.

This study aimed to investigate the common types and directions of root fractures of the maxillary first molar and the influence of root canal treatment on the prevalent sites of root fractures. A total of 274 maxillary first molars with root fractures diagnosed via cone beam computed tomography were included. The root fractures of nonendodontically and endodontically treated teeth were identified to be spontaneous and secondary root fractures, respectively. The sites, types, and directions of spontaneous and secondary root fractures were determined. Among the spontaneous root fractures, the proportion of palatal root fractures (56.1%) was higher than those of mesial buccal root fractures (36.1%) and distal buccal root fractures (7.8%). Among the secondary root fractures, the proportion of mesial buccal root fractures (52.7%) was higher than those of palatal root fractures (36.5%) and distal buccal root fractures (10.8%). The distribution of predominant fracture sites was statistically significant (P<0.05), and vertical root fracture was the most common type. Palatal and buccal roots were commonly fractured at the mesiodistal and buccal-palatal directions, respectively. This study provided an epidemiological basis for the clinical features of root fractures of the maxillary first molar. During the dia-gnosis and treatment of the maxillary first molar, the possibility of palatal root fractures should be considered. The occurrence of mesial buccal root fractures may be related to root canal treatment. Therefore, the risk of mesial buccal root fractures caused by iatrogenic factors should be minimized.