A systematic review and meta-analysis of the prevalence and global distribution of middle mesial canals in mandibular molars identified by CBCT.

OBJECTIVES: This systematic review and meta-analysis aimed to evaluate the prevalence of middle mesial canal (MMC) in permanent mandibular molars of different populations and regions based on cone-beam computed tomography (CBCT) studies. MATERIALS AND METHODS: PubMed, Scopus, Embase, Web of Science, and Open-Grey were searched up to October 2023 according to specific keywords. A hand search was conducted on the references of the included studies and articles from three peer-reviewed journals in endodontics. The main variable of interest was the prevalence of MMC. Additional data such as the total number of included cases, age and country of the population, CBCT device information, voxel size, and field of view details were also extracted. Extracted data were analyzed qualitatively with the JBI quality assessment checklist and quantitatively with STATA software. RESULTS: Of 32,793 studied teeth, the cumulative prevalence of MMC in both mandibular 1st and 2nd molars was 3.11% (95% CI: 2.00-4.44%). The subgroup analysis reveals a prevalence of 4.15% (95% CI: 2.69-5.89%) for mandibular 1st molars and 1.2% (95% CI: 0.2-2.83%) for mandibular 2nd molars. The highest prevalence of MMC in 1st molar was attributed to South Asia (11.24%) and Africa (6.61%). CONCLUSIONS: The prevalence of MMC varies among regions. Clinicians should be aware of the potential prevalence of MMC, particularly in mandibular first molars, as a missed MMC could result in endodontic failure. CLINICAL RELEVANCE: The presence of MMCs varies in different geographic regions (0% to 29.7%). Clinicians should always look for MMC when doing an endodontic treatment on mandibular molars, as the presence of this canal is not uncommon. We suggest searching for this canal as if searching for the second mesiobuccal canal of maxillary 1st molars.

Enhancing Coronal Adaptation of Root Canal Fillings with a Modified Single-Cone Obturation Technique: Two Case Reports.

The single-cone technique, also known as the hydraulic condensation technique, is widely employed in endodontics. However, the aforementioned method is presented with certain limitations; specifically concerning the coronal seal and the adaptation of the coronal third of a master gutta-percha (GP) with a round cross-section to the coronal dentinal walls of root canals with semi-round or oval cross-sections. Through two case reports, the current article introduces the coronal vertical condensation (CVC) technique; aiming to enhance GP adaptation to canal walls in similar scenarios. In fact, the coronal vertical condensation technique amalgamates the different aspects of warm vertical condensation and single-cone techniques. In CVC, following the placement of the master GP cone, an electrical heat carrier is inserted immediately a few millimeters apical from the canal orifice to remove the coronal portion of the master GP cone. Subsequently, a hand plugger is used to condense GP in the vertical dimension, and the coronal space is backfilled using melted GP. The implementation of CVC technique has demonstrated an improved coronal adaptation of GP with canal walls. The stated technique seems beneficial; especially in the obturation of severely curved canals or root canals with a final preparation shape of variable taper.

Micro-CT Evaluation of Four Root Canal Obturation Techniques.

PURPOSE: The aim of this in vitro study was to evaluate the quality of four root canal obturation techniques using microcomputed tomography (micro-CT). MATERIALS AND METHODS: A total of 36 mandibular first premolars with mostly round canals were decoronated, then instrumented up to a size F3 rotary file, and dressed with an epoxy resin-based sealer. Subsequently, they were divided into 4 different groups (n = 9) based on the method of obturation: lateral condensation using 0.02 tapered master cone (LC2), lateral condensation using 0.04 tapered master cone (LC4), matched single-cone technique (MS), and matched single cone-mediated ultrasonic activation (MSUA). All the teeth were scanned using micro-CT (resolution of 19 µm), and the percentage volume of voids was calculated. One-way analysis of variance and Tukey test were used to analyze the data (α = 0.05). RESULTS: The total percentage volume of voids was significantly lower in the MSUA group compared to all other groups (P < 0.05). The total percentage volume of voids was significantly lower in the MS group compared to the LC4 (P < 0.001) and LC2 (P < 0.001) groups. However, there was no significant difference between the LC2 and LC4 groups (P < 0.65). CONCLUSIONS: MSUA, significantly, showed the least root canal filling voids amongst all the obturation techniques studied. MSUA can be considered an effective method for the filling of the round root canals. In general, lateral condensation using either 0.02 or 0.04 tapered master cones had significantly the highest volume percentage of voids amongst the experimental groups.

Systems Biology-Derived Genetic Signatures of Mastitis in Dairy Cattle: A New Avenue for Drug Repurposing.

Mastitis, a disease with high incidence worldwide, is the most prevalent and costly disease in the dairy industry. Gram-negative bacteria such as Escherichia coli (E. coli) are assumed to be among the leading agents causing acute severe infection with clinical signs. E. Coli, environmental mastitis pathogens, are the primary etiological agents of bovine mastitis in well-managed dairy farms. Response to E. Coli infection has a complex pattern affected by genetic and environmental parameters. On the other hand, the efficacy of antibiotics and/or anti-inflammatory treatment in E. coli mastitis is still a topic of scientific debate, and studies on the treatment of clinical cases show conflicting results. Unraveling the bio-signature of mastitis in dairy cattle can open new avenues for drug repurposing. In the current research, a novel, semi-supervised heterogeneous label propagation algorithm named Heter-LP, which applies both local and global network features for data integration, was used to potentially identify novel therapeutic avenues for the treatment of E. coli mastitis. Online data repositories relevant to known diseases, drugs, and gene targets, along with other specialized biological information for E. coli mastitis, including critical genes with robust bio-signatures, drugs, and related disorders, were used as input data for analysis with the Heter-LP algorithm. Our research identified novel drugs such as Glibenclamide, Ipratropium, Salbutamol, and Carbidopa as possible therapeutics that could be used against E. coli mastitis. Predicted relationships can be used by pharmaceutical scientists or veterinarians to find commercially efficacious medicines or a combination of two or more active compounds to treat this infectious disease.

Effect of calcium hydroxide on inflammatory root resorption and ankylosis in replanted teeth compared with other intracanal materials: a review.

Calcium hydroxide (CH) is the gold-standard intracanal dressing for teeth subjected to traumatic avulsion. A common complication after the replantation of avulsed teeth is root resorption (RR). The current review was conducted to compare the effect of CH with that of other intracanal medications and filling materials on inflammatory RR and replacement RR (ankylosis) in replanted teeth. The PubMed and Scopus databases were searched through June 2018 using specific keywords related to the title of the present article. The materials that were compared to CH were in 2 categories: 1) mineral trioxide aggregate (MTA) and endodontic sealers as permanent filling materials for single-visit treatment, and 2) Ledermix, bisphosphonates, acetazolamide, indomethacin, gallium nitrate, and enamel matrix-derived protein (Emdogain) as intracanal medicaments for multiple-visit management of avulsed teeth prior to the final obturation. MTA can be used as a single-visit root filling material; however, there are limited data on its efficacy due to a lack of clinical trials. Ledermix and acetazolamide were comparable to CH in reducing RR. Emdogain seems to be an interesting material, but the data supporting its use as an intracanal medication remain very limited. The conclusions drawn in this study were limited by the insufficiency of clinical trials.

The efficacy of the reverse contrast mode in digital radiography for the detection of proximal dentinal caries.

PURPOSE: This study evaluated the diagnostic accuracy of the reverse contrast mode in intraoral digital radiography for the detection of proximal dentinal caries, in comparison with the original digital radiographs. MATERIALS AND METHODS: Eighty extracted premolars with no clinically apparent caries were selected, and digital radiographs of them were taken separately in standard conditions. Four observers examined the original radiographs and the same radiographs in the reverse contrast mode with the goal of identifying proximal dentinal caries. Microscopic sections 5 µm in thickness were prepared from the teeth in the mesiodistal direction. Four slides prepared from each sample used as the diagnostic gold standard. The data were analyzed using SPSS (α=0.05). RESULTS: Our results showed that the original radiographs in order to identify proximal dentinal caries had the following values for sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, respectively: 72.5%, 90%, 87.2%, 76.5%, and 80.9%. For the reverse contrast mode, however, the corresponding values were 63.1%, 89.4%, 87.1%, 73.5%, and 78.8%, respectively. The sensitivity of original digital radiograph for detecting proximal dentinal caries was significantly higher than that of reverse contrast mode (p<0.05). However, no statistically significant differences were found regarding specificity, positive predictive value, negative predictive value, or accuracy (p>0.05). CONCLUSION: The sensitivity of the original digital radiograph for detecting proximal dentinal caries was significantly higher than that of the reversed contrast images. However, no statistically significant differences were found between these techniques regarding specificity, positive predictive value, negative predictive value, or accuracy.

Technical quality of root canal therapies performed by novice dental students in preclinical practice.

BACKGROUND: For improving the quality of endodontic performance of practitioners in clinical practice, their basic, preclinical performance and knowledge must be taken into consideration. This study aimed to radiographically evaluate the technical quality of preclinical molar root canal treatments (RCTs) performed by undergraduate dental students at a dental school in Iran. Further, the effect of using Gates-Glidden (GG) drills on the final quality of RCTs was evaluated. MATERIALS AND METHODS: In this retrospective cross-sectional study, 315 roots of 105 endodontically treated teeth in preclinical practice were evaluated radiographically. The analyzed quality parameters included length, taper and density of fillings, which were scored as S2 (adequate standard), the S1 (slight deviation), or S0 (considerable deviation). For all the parameters, acceptable, moderate and poor fillings received total scores of 6, 3-5 and 0-2, respectively. There were two groups of students: One group had used only K-files, and the other had used K-files along with GG drills. The quality of RCTs between these groups was evaluated using the aforementioned scoring protocol. The results were analyzed using Chi-square, Mann-Whitney and Fisher's exact tests (α = 0.05). RESULTS: Under-fillings (P = 0.001) and under-shapings (P = 0.007) occurred mostly in mandibular root fillings. A lower density was found in maxillary fillings (P < 0.001). No relationship was observed between the technique used (irrespective of GG drills usage) and length (P = 0.499) and taper of fillings (P = 0.238). The roots instrumented with GG drills had a higher filling density (P = 0.004). The quality mean score of RCTs was improved when GG drills were used (P = 0.008). CONCLUSION: The technical quality of preclinical molar RCTs performed by undergraduate dental students was considered acceptable in 35.6% of the cases. When GG drills were used along with K-files, the technical quality of RCTs was enhanced.

A 7-year study of 1,278 patients with maxillofacial trauma and cerebrospinal fluid leak.

BACKGROUND: A number of patients with facial fractures have cerebrospinal fluid (CSF) leak that may result in meningitis and other central nervous system complications. Commonly, CSF leak occurs following trauma, but the etiology and pattern of this disorder are different from region to region. This study aims to evaluate the distribution of CSF leak in patients with maxillofacial fractures in Isfahan province, Iran. PATIENTS AND METHODS: In this retrospective cross-sectional study, 1,287 medical files of patients admitted to a medical center with head and face injuries were evaluated during a 7-year period (2004-2010). Data was obtained using descriptive analysis. RESULTS: Of the 1,278 patients with head and maxillofacial fractures, 16 (1.25 %) males and one (0.07 %) female had CSF leak; all these cases had skull base fracture. Of these, 52.9 % had maxillary fracture, 23.5 % nasal fracture, 41.1 % orbital fracture, 11.7 % mandibular fracture, 23.5 % frontal fracture, and 41.1 % had more than one site of fracture. 58.8 % had rhinorrhea and 41.2 % otorrhea. Of all these patients with CSF leak, 8 (47 %), 2 (11.8 %), and 7 (41.2 %) cases were treated spontaneously, using lumbar drain placement, and by surgical intervention, respectively. CONCLUSIONS: Cerebrospinal fluid leak was observed most frequently in patients with fracture in the zygomatic and maxillary bone, and mostly exhibited itself as rhinorrhea and/or otorrhea. All cases with CSF leak had skull base fracture as well. However, post-traumatic CSF leaks are uncommon and are generally treated without surgical intervention (59 %). Distribution of CSF leak varies from one region to another and knowing this fact helps to manage the injury and prevent the complications.

Orthodontic Extraction of High-Risk Impacted Mandibular Third Molars in Close Proximity to the Mandibular Canal: A Systematic Review.

PURPOSE: Extraction of mandibular third molars (M3s) in close proximity to the mandibular canal has some inherent risks to adjacent structures, such as neurologic damage to teeth, bone defects distal to the mandibular second molar (M2), or pathologic fractures in association with enlarged dentigerous cysts. The procedure for extrusion and subsequent extraction of high-risk M3s is called orthodontic extraction. This is a systematic review of the available approaches for orthodontic extraction of impacted mandibular M3s in close proximity to the mandibular canal and their outcomes. MATERIALS AND METHODS: The PubMed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), DOAJ, Google Scholar, OpenGrey, Iranian Science Information Database (SID), Iranmedex, and Irandoc databases were searched using specific keywords up to June 2, 2014. Studies were evaluated based on predetermined eligibility criteria, treatment approaches, and their outcomes. RESULTS: Thirteen articles met the inclusion criteria. A total of 123 impacted teeth were extracted by orthodontic extraction and 2 cases were complicated by transient paresthesia. Three types of biomechanical approaches were used: 1) using the posterior maxillary region as the anchor for orthodontic extrusion of lower M3s, 2) simple cantilever springs attached to the M3 buttonhole, and 3) cantilever springs tied to a bonded orthodontic bracket on the M3 plus multiple-loop spring wire for distal movement of the M3. Osteo-periodontal status of M2s also improved uneventfully. CONCLUSION: Despite the drawbacks of orthodontic extraction, removal of deeply impacted M3s using the described techniques is safe with regard to mandibular nerve injury and neurologic damage. Orthodontic extraction is recommended for extraction of impacted M3s that present a high risk of postoperative osteo-periodontal defects on the distal surface of the adjacent M2 and those associated with dentigerous cysts.

Can ambient orange fragrance reduce patient anxiety during surgical removal of impacted mandibular third molars?

PURPOSE: To investigate whether ambient orange fragrance, compared with no fragrance, can reduce patient anxiety before and during surgical removal of an impacted mandibular third molar. MATERIALS AND METHODS: In the present randomized clinical trial, the patients who required extraction of an impacted mandibular third molar and fulfilled the predetermined criteria were included. A dental anxiety scale (DAS) questionnaire was used to determine the anxiety level of the patients before surgery. Only patients with moderate and high anxiety levels (DAS scale ≥ 9 to ≤ 14) were included. The predictor variable was fragrance exposure. The fragrance group was exposed to orange fragrance, and the control group was exposed to no fragrance. The outcome variables were physiologic measures related to anxiety, including the mean blood pressure, respiratory rate, and pulse rate. The physiologic vital changes were determined before and during the surgical procedure. The data were analyzed using the independent t test, χ(2) test, and Mann-Whitney U test (Statistical Package for Social Sciences, version 16; α = 0.05). RESULTS: A total of 56 patients fulfilled the inclusion criteria (fragrance group, 19 males and 9 females; no-fragrance group, 12 males and 16 females). Before entering the waiting room, the patients' vital signs were recorded twice. No significant differences were found between the 2 groups. The mean blood pressure, pulse rate, and respiratory rate were significantly lower in the fragrance group during surgery (from sitting in the dental chair to the end of surgery; P < .05). CONCLUSIONS: The results of our study have shown that orange fragrance is effective in reducing the anxiety related to surgical removal of an impacted mandibular third molar.

Surface characteristics and bioactivity of a novel natural HA/zircon nanocomposite coated on dental implants.

The surface characteristics of implant which influence the speed and strength of osseointegration include surface chemistry, crystal structure and crystallinity, roughness, strain hardening, and presence of impurities. The aim of this study was to evaluate the bioactivity and roughness of a novel natural hydroxyapatite/zircon (NHA/zircon) nanobiocomposite, coated on 316L stainless steel (SS) soaked in simulated body fluid (SBF). NHA/zircon nanobiocomposite was fabricated with 0 wt.%, 5 wt.%, 10 wt.%, and 15 wt.% of zircon in NHA using ball mill for 20 minutes. The composite mixture was coated on 316L SS using plasma spray method. The results are estimated using the scanning electron microscopy (SEM) observation to evaluate surface morphology, X-ray diffraction (XRD) to analyze phase composition, and transmission electron microscopy (TEM) technique to evaluate the shape and size of prepared NHA. Surfaces roughness tester was performed to characterize the coated nanocomposite samples. The maximum average R a (14.54 µm) was found in the NHA 10 wt.% of zircon coating. In addition, crystallinity (X c ) was measured by XRD data, which indicated the minimum value (X c = 41.1%) for the sample containing 10 wt.% of zircon. Maximum bioactivity occurred in the sample containing 10 wt.% of zircon, which was due to two reasons: first, the maximum roughness and, second, the minimum crystallinity of nanobiocomposite coating.

Juvenile Myoclonic Epilepsy (JME): Neuropsychological Profile and Related Factors with Cognitive Dysfunction.

OBJECTIVE: The aim of present study was to verify possible cognitive dysfunction in the patients with Juvenile Myoclonic Epilepsy (JME) and its correlation to factors related to epilepsy and patients demographic variables. MATERIAL AND METHODS: Thirty two consecutive patients with JME and 32 healthy controls were evaluated in neuropsychological domains including orientation, mental control, logical memory, forward and backward digit spans, visual memory, associative learning, and memory quotient (using Persian version of Wechsler Memory Scale (WMS)-Revised), preservative errors (using Wisconsin Card Sorting Test (WCST)), Stroop Test (color and word), IQ score (using Raven's Progressive Matrices test), and depression (using the Persian version of Beck Depression Inventory (BDI)). SPSS 11.0 (SPSS Inc., Chicago, Illinois, USA) software was used for statistical analysis. Student's t-test and the Mann-Whitney U-test were used for independent normally and non-normally distributed continuous variables, respectively. RESULTS: Our study showed significant differences between patients with JME and control group with respect to scores of mental control (p=0.015), forward digit span (p=0.004), total digit span (p=0.008) and IQ (p=0.003). In addition, age, education level, duration of epilepsy and medication showed an impact on several cognitive functions in the patients with JME. CONCLUSION: It is indicated that JME is associated with impairment in specific cognitive domains, despite any evidence in favor of depression.