Anaesthetic efficacy of incorporating different additives into lidocaine for the inferior alveolar nerve block: A systematic review with meta-analysis and trial sequential analysis.

BACKGROUND: Incorporating an additive into lidocaine is a method to enhance the efficacy of the inferior alveolar nerve block (IANB) in mandibular posterior teeth. OBJECTIVES: To assess the efficacy of incorporating additives into lidocaine in the success rate of IANB for teeth with the diagnosis of normal pulp (NP) or symptomatic irreversible pulpitis (SIP). METHODS: Randomized controlled trials (RCTs) assessing the incorporation of additives into lidocaine on the pulpal anaesthesia success rate of mandibular posterior teeth were searched in PubMed, Scopus, Web of Science, Ovid, EBSCO, Embase, and Cochrane databases up to 1 December 2021. The risk of bias (RoB) was assessed by the Cochrane Risk of Bias Tool. A random-effects model was employed to calculate the pooled risk ratio (RR) with a 95% confidence interval (CI), using STATA 16. The trial sequential analysis (TSA) was applied to calculate the required information size (RIS). The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to assess the certainty of the evidence. RESULTS: Of 6966 records retrieved initially, 14 trials (8 for NP and 6 for SIP groups) were included in qualitative and quantitative syntheses. All trials were categorized as low and unclear RoB for NP and SIP groups, respectively. In the NP group, with 307 participants, no significant effect was observed for additives incorporated into lidocaine (RR: 0.84; 95% CI: 0.53-1.32; I2  = 98%). Subgroup analysis revealed that adding mannitol led to a higher success rate (RR = 1.24; 95% CI: 1.15-1.34; I2  = 7.16%). In the SIP group, with 434 participants, no significant effect was shown when the additives were incorporated (RR = 1.22; 95% CI: 0.98-1.52; I2  = 0%). Likewise, in subgroup analysis, incorporating mannitol or sodium bicarbonate demonstrated no significant effect (RR = 1.76; 95% CI: 0.93-3.32; I2  = 18.41% and RR = 1.06; 95% CI: 0.65-1.72; I2  = 53.5%, respectively). DISCUSSION: TSA revealed that the outcome was "inconclusive" for each group. The certainty of the evidence was graded as "very low" and "low" for NP and SIP groups, respectively. CONCLUSIONS: The very low to low certainty of evidence indicated that incorporating additives into lidocaine did not increase the efficacy of IANB and supplemental injections are still necessary to help practitioners achieve painless dentistry. REGISTRATION: PROSPERO database (CRD42020132585).

The applications of ultrasound, and ultrasonography in dentistry: a scoping review of the literature.

OBJECTIVES: This scoping review aims to summarize the available literature on the clinical applications of ultrasonography and ultrasound in diagnostic, therapeutic, and interventional dental applications. MATERIALS AND METHODS: We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Extension for Scoping Reviews checklist and conducted a protocol-driven scoping review of randomized controlled trials, cohort studies, cross-sectional studies, case-control studies, and case series that assessed ultrasonography or ultrasound use as a stand-alone diagnostic, therapeutic, and interventional tool in dentistry. We included studies published after 1980, study samples ≥ 10, with diagnostic, concordance, or therapeutic outcomes. We searched Ovid MEDLINE, Embase, and others (up to April 2021) and extracted information regarding study level, patient level, test or treatment level, and outcome level data. RESULTS: Five interventional studies (related to oral medicine, temporomandibular disorders, and dental anesthesia), eight therapeutic studies (related to surgery and orthodontics), and seventy-five diagnostic studies (related to orthodontics, surgery, endodontics, oral medicine, temporomandibular disorders, restorative dentistry, and periodontology) were identified and presented in this review. CONCLUSION: Ultrasonography has a well-established niche in diagnostic dentistry, while therapeutic and interventional ultrasounds have a smaller, yet present, niche in dentistry. However, further research is needed to report the precise estimates of the diagnostic, therapeutic, and interventional effects. CLINICAL SIGNIFICANCE: Dentists are mostly unfamiliar with ultrasonography and ultrasound and their potential uses. This review maps the diagnostic and therapeutic applications of ultrasonography and ultrasound technology in dentistry and highlights the current challenges, gaps of knowledge, and research status of ultrasound technology in this regard.

Immediate and Delayed Post Space Preparations in Endodontically Treated Teeth: A Scoping Review.

BACKGROUND: The aim of the present review was to identify the effect of the post-space preparation (PSP) timing (immediate or delayed) on endodontically treated teeth. METHODS: All studies in any language that compared the effect of immediate versus delayed PSP on the outcomes of an endodontically treated tooth were searched in PubMed, Scopus, Web of Science, Cochrane, ProQuest, WorldCat, and Google Scholar databases by two independent researchers until February 12, 2022. Studies assessing merely the immediate or delayed PSP were excluded. A descriptive analysis was performed to evaluate the study design and the characteristics of the included studies. RESULTS: The initial search yielded 2612 records, of which 68 were included. Except for one randomized controlled trial, all were in vitro. The evaluated variables were apical/coronal microleakage (n = 48/n = 1), post-bond strength (n = 8), bacterial infiltration (n = 7), presence of voids (n = 3), apical extrusion and residual of filling material (n = 1), and post-operative pain (n = 1). The number of publications had steady growth per year and fast growth per decade. "Post-space preparation" was the most popular keywords. CONCLUSIONS: The present review highlights the need for further investigations due to the various design of studies, controversial results, and an inadequate number of randomized controlled trials. TRIAL REGISTRATION: Retrospectively registered. Open Science ( https://doi.org/10.17605/OSF.IO/2YTM6 ).

Effect of buccal fat autotransplantation on improving the alveolar socket bone regeneration: An in-vivo study.

Background: There are various materials used for socket preservation following dental extraction. The aim of the present animal study was to histologically investigate the efficacy of buccal fat autotransplantation on alveolar bone regeneration following dental extraction. Study design: In this prospective, double-blind laboratory experiment with a split-mouth design, 16 mandibular second premolar teeth in eight beagle dogs were extracted, and half of the extraction sockets were randomly filled using buccal fat autotransplantation. Other samples were left untouched to heal normally by the formed blood clot. Buccal fat autotransplantation was the primary predictor variable, and the type and amount of newly formed bone were the primary outcome variables. Assessment methods were the H & E coloring technique and histomorphometric evaluation. The significance level was set at 0.05, and data was subjected to Chi-Square and Wilcoxon signed-rank tests using SAS statistical software version 9.4. Results: From the total number of 16 samples in 8 dogs, 50% of the samples in the intervention group represented inflammation with lower intensity compared to 33% in the control group; however, this difference was not considered statistically significant (Chi-Square test, P-value = 0.55). Wilcoxon test results showed no statistically significant difference between the two groups regarding the mean amount of total bone formation (Z = 0.00, P-value = 1.00). Conclusion: It was inferred from the outcomes of the present study that when compared to the normal healing of the socket, buccal fat autotransplantation did not represent with superior outcome concerning the socket bone regeneration.

MicroRNAs-mediated regulation of the differentiation of dental pulp-derived mesenchymal stem cells: a systematic review and bioinformatic analysis.

BACKGROUND: Human dental pulp-derived mesenchymal stem cells (hDP-MSCs), which include human dental pulp stem cells (hDPSCs) and stem cells from human exfoliated deciduous teeth (SHEDs), are promising cell sources for regenerative therapies. Nevertheless, a lack of knowledge relating to the mechanisms regulating their differentiation has limited their clinical application. microRNAs (miRNAs) are important regulatory molecules in cellular processes including cell differentiation. This systematic review aims to provide a panel of miRNAs that regulate the differentiation of hDP-MSCs including hDPSCs and SHEDs. Additionally, bioinformatic analyses were conducted to discover target genes, signaling pathways and gene ontologies associated with the identified miRNAs. METHODS: A literature search was performed in MEDLINE (via PubMed), Web of Science, Scopus, Embase and Cochrane Library. Experimental studies assessing the promotive/suppressive effect of miRNAs on the differentiation of hDP-MSCs and studies evaluating changes to the expression of miRNAs during the differentiation of hDP-MSCs were included. miRNAs involved in odontogenic/osteogenic differentiation were then included in a bioinformatic analysis. A miRNA-mRNA network was constructed, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed. A protein-protein interaction (PPI) network was also constructed. RESULTS: Of 766 initially identified records through database searching, 42 and 36 studies were included in qualitative synthesis and bioinformatic analyses, respectively. Thirteen miRNAs promoted and 17 suppressed odontogenic/osteogenic differentiation of hDP-MSCs. hsa-miR-140-5p, hsa-miR-218 and hsa-miR-143 were more frequently reported suppressing the odontogenic/osteogenic differentiation of hDP-MSCs. hsa-miR-221 and hsa-miR-124 promoted and hsa-miR-140-5p inhibited neuronal differentiation, hsa-miR-26a-5p promoted and hsa-miR-424 suppressed angiogenic differentiation, and hsa-miR-135 and hsa-miR-143 inhibited differentiation within myogenic lineages. A miRNA-mRNA network including 1890 nodes and 2171 edges was constructed. KEGG pathway analysis revealed MAPK, PI3K-Akt and FoxO as key signaling pathways involved in the odontogenic/osteogenic differentiation of hDP-MSCs. CONCLUSIONS: The findings of this systematic review support the potential application of the specific miRNAs to regulate the directed differentiation of hDP-MSCs in the field of regenerative therapies.

Apical transportation with different root canal preparation techniques using edgEEvolve rotary instruments.

Background: This study aimed to investigate the extent of apical transportation following instrumentation with EdgeEvolve rotary instruments applying single-length and crown-down techniques. Materials and Methods: In this experimental in-vitro study, 60 mandibular molars with mesiobuccal curvatures of 20°-40° were selected, and digital radiographic images were taken. Teeth were randomly assigned into two groups of single-length and crown-down preparation techniques. In both mentioned groups, EdgeEvolve rotary system was used. After preparation, the same as the previous ones, digital radiographic images were taken from the canals. The data were analyzed using Student' t-test and ShapiroWilk normality test (P = 0.05). Results: The mean standard deviation (SD) for apical transportation in the single-length and the crown-down group was 4.42 (2.9) and 7.48 (3.9) degrees, respectively (P < 0.05). The mean SD of the preparation time in the single-length and crown-down group was 135.07 (30.8) and 109.07 (20.8), respectively (P < 0.05). The apical transportation and the time of preparation between the two groups were significant. Conclusion: Using EdgeEvolve rotary instruments canal preparation with both single-length and crown-down techniques led to some degrees of apical transportation.

A Scoping Review of Four Decades of Outcomes in Nonsurgical Root Canal Treatment, Nonsurgical Retreatment, and Apexification Studies: Part 3-A Proposed Framework for Standardized Data Collection and Reporting of Endodontic Outcome Studies.

INTRODUCTION: Despite initiatives to standardize and improve reporting of rapidly growing endodontic outcome research studies, issues related to missing and ambiguous information are still of great concern. In this article, we propose a framework for standardized data collection and a compiled checklist for reporting of various study designs on endodontic outcome. METHODS: A comprehensive search was carried out to locate randomized controlled trials, cohorts, case-control studies, or case series of >100 patients that reported on endodontic outcomes. We reviewed these articles to develop a Data Collection Template and compiled a checklist for reporting of future endodontic outcome research. RESULTS: Out of 354 eligible articles previously reported in our scoping review on endodontic outcome studies, 109 articles were selected and screened for study variables or levels of categorization. Our complied Data Collection Template was developed in 19 domains to highlight important demographic, preoperative, intraoperative, and postoperative variables. Because of the specific needs for endodontic outcome literature, we also proposed a compiled checklist (consisting of 4 main domains) to facilitate the reporting of various study designs on endodontic outcome studies. This checklist included simple descriptions of the required items and examples on reporting from published endodontic studies. CONCLUSIONS: By facilitating the collection and reporting of relevant research data by investigators in private practice and academia, we hope that the proposed Data Collection Template and reporting guideline can highlight the importance of standardization among clinicians and researchers while producing valid scientific information that will support evidence-based treatment decisions.

A Scoping Review of 4 Decades of Outcomes in Nonsurgical Root Canal Treatment, Nonsurgical Retreatment, and Apexification Studies-Part 2: Outcome Measures.

INTRODUCTION: Inconsistencies in the definitions of endodontic outcome terminology jeopardize evaluations of proposed interventions and patient care quality. This scoping review aimed to provide groundwork to develop a set of basic outcomes in endodontics. METHODS: We performed a comprehensive literature search for randomized controlled trials, cohort studies, case-control studies, and case series (≥10 patients) published after 1980 with patients ≥10 years of age with any preoperative pulpal and periapical diagnosis in permanent teeth requiring nonsurgical root canal treatment, retreatment, or apexification. Abstracted data on outcome assessment methods, assessors, and domains were reported after univariate and bivariate analyses. RESULTS: Treatment outcomes were evaluated radiographically (88%) or clinically (73%). Although 2-dimensional radiography exceeded 3-dimensional radiography, the use of the latter has increased since 2010, mostly for nonsurgical retreatments. Of 19 identified outcomes, 5 were most frequent: success (168 studies, 40%), radiographic healing (128 studies, 30%), survival (of an asymptomatic tooth [48 studies, 12%] or of a procedure code in administrative databases [31 studies, 7%]), pain assessment (14 studies, 3%), and quality of life (11 studies, 3%). Clinician-centered outcomes have been most frequently studied since the 1980s (71%), in academic settings (76%), and using a prospective design (45%). Patient-centered outcomes were reported in 19% of studies before 2010 and 30% since 2010. They were more common among retrospective studies (49%). CONCLUSIONS: Patient-centered outcome measures are lacking in endodontic studies. The state of available research can provide a baseline for the development of a core outcome set in endodontics, which should represent the important patient-centered outcomes in conjunction with well-validated clinician-centered outcomes.

A Scoping Review of 4 Decades of Outcomes in Nonsurgical Root Canal Treatment, Nonsurgical Retreatment, and Apexification Studies-Part 1: Process and General Results.

INTRODUCTION: Despite initiatives to standardize reports, variances in study design, outcomes assessed, and tools used are persistent in the literature. This review scoped the existing literature on endodontic outcome studies for future development of core outcome sets. METHODS: A comprehensive literature search of randomized controlled trials, cohort studies, case-control studies, and case series (≥10 patients) published after 1980 including patients ≥10 years of age with any preoperative pulpal and periapical diagnosis in permanent teeth requiring nonsurgical root canal treatment (NS-RCT), retreatment (NS-ReTx), or apexification was performed. Abstracted data were reported through descriptive statistics. RESULTS: Of the 9957 studies screened, 354 were included. An increase in the quantity of endodontic outcome publications and levels of evidence in their study design was noted over the past 4 decades. Although 41% of the studies included participants 26-50 years of age, literature including participants >50 years old has increased since 2000. Apexification and NS-ReTx were mostly provided by specialists and postgraduate students. The most common follow-up period was 2-5 years (35%), and most randomized controlled trials (58%) reported follow-up times <1 year. Multiple-visit treatment was most common in apexification studies (85%). Deficiency, inconsistency, and ambiguity were observed across many reports. CONCLUSIONS: NS-ReTx and NS-RCT/NS-ReTx studies have increased over the past 2 decades, particularly those focusing on molars and patients >50 years old. Despite the progress in endodontic research, heterogeneity in reporting styles yields considerable limitations, particularly data standardization challenges and inconsistencies in methods and results reporting. This scoping review highlighted the state of available research and supported the development of standardized guidelines for future investigations.

Isolation and Differentiation of Adipose-Derived Stem Cells into Odontoblast-Like Cells: A Preliminary In Vitro Study.

OBJECTIVE: The aim of present study was to isolate and differentiate human adipose-derived stem cells (ASCs) into odontoblast-like cells. MATERIALS AND METHODS: In this experimental study, human adipose tissues were taken from the buccal fat pad of three individuals (mean age: 24.6 ± 2.1 years). The tissues were transferred to a laboratory in a sterile culture medium, divided into small pieces and digested by collagenase I (2 mg/mL, 60-90 minutes). ASCs were isolated by passing the cell suspension through cell strainers (70 and 40 µm), followed by incubation at 37ºC and 5% CO2 in Dulbecco's modified eagle medium (DMEM) supplemented with fetal bovine serum (FBS 5%) and penicillin/streptomycin (P/S). After three passages, the ASCs were harvested. Subsequently, flow cytometry and reverse transcriptase polymerase chain reaction (RT-PCR) were used to detect expression levels of NANOG and OCT4 to evaluate stemness. Then, a differentiation medium that included high-glucose DMEM supplemented with 10% FBS, dexamethasone (10 nM), sodium ß-glycerophosphate (5 mM) and ascorbic acid (100 µM) was added. The cells were cultivated for four weeks, and the odontogenic medium was changed every two days. Cell differentiation was evaluated with Alizarin red staining and expressions of collagen I (COL1A1), dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP1). RESULTS: The ASCs were effectively and easily isolated. They were negative for CD45 and positive for the CD105 and CD73 markers. The ASCs expressed OCT4 and NANOG. Differentiated cells highly expressed DSPP, COL1A1 and DMP1. Alizarin red staining revealed a positive reaction for calcium deposition. CONCLUSION: ASCs were isolated successfully in high numbers from the buccal fat pad of human volunteers and were differentiated into odontoblast-like cells. These ASCs could be considered a new source of cells for use in regenerative endodontic treatments.

Improving pulp revascularization outcomes with buccal fat autotransplantation.

Several techniques have been introduced to improve the pulp revascularization outcomes. The use of the tissue graft can create more practical tissue regeneration, provide vascular supply, and enhance tissue healing. The aim of the present study was to investigate the histologic and molecular outcomes of pulp revascularization with buccal fat autotransplantation. Fifty-six open apex roots from four dogs aged 4-6 months were randomly allocated to five groups of endodontic regeneration models: Group 1 (negative control, n = 4); Group 2 (control and without intervention, n = 4); Group 3 (blood clot, n = 16); Group 4 (buccal fat autotransplantation, n = 16); and Group 5 (blood clot plus buccal fat autotransplantation, n = 16). After 3 months, the extracted dog teeth were analyzed by histological and immunohistochemical techniques. Furthermore, real-time quantitative polymerase chain reactions were implemented to assess the gene expression profiles of dentin sialophosphoprotein (DSPP), dentin matrix protein (DMP), collagen I (COL1), and alkaline phosphatase (ALP) on regenerated tissue in the root canals. There were no significant differences in the severity of inflammation and necrosis between intervention groups. Immunohistochemical analysis showed significant differences among the study groups in expression level of extracellular glycoproteins such as fibronectin, laminin, and tenascin C. Group 5 showed an increase in the expression of DMP1 and COL1 genes. The expression of DSPP gene increased significantly in Group 4. The expression of ALP gene increased significantly in Group 3. Using this procedure may open new fields of research for regenerative endodontic procedure in which tissue autotransplant, particularly adipose tissue, may improve the outcomes of pulp revascularization.

Analysis of highly tweeted dental journals and articles: a science mapping approach.

Aim We aimed to rank dental journals according to the number of Twitter mentions related to their articles. We set out to analyse and visualise the bibliometric characteristics of highly tweeted articles.Methods Twitter mentions were extracted from the Altmetric database. Bibliometric data were obtained from the Web of Science and analysed by VOSviewer software. Hotspots among highly tweeted articles visualised by keyword co-occurrence network analysis. Bibliographic coupling network analysis was used to find the most influential journals, institutions and countries.Results A total of 20,520 Twitter accounts which shared 93,776 tweets related to 23,686 articles from 91 journals were analysed. The British Dental Journal had the highest number of Twitter mentions related to dental articles. Children, dental caries, and periodontal disease were the hottest topics among the 134 highly tweeted dental articles. @The_BDJ had the highest number of tweets related to dental articles, followed by @Dddent2 and @gary_takacs. @TheBDA had the highest number of followers, followed by @Dddent2 and @The_BDJ.Discussion Ground breaking issues such as genomic medicine, stem cells, tissue engineering, nanotechnology, and artificial intelligence were not seen among the highly tweeted dental articles. In the 'Twittersphere', some independent scientists are more active than well-known dental organisations and journals. The journals are strongly recommended to be proactive in Twittersphere, to set up their own Twitter profile, and to promote their visibility and social impact by immediately tweeting the articles. Researchers should be alert to the overuse of Twitter in scholarly communications. The Kardashian index will be a useful tool to measure the over/under activity of a researcher on Twitter.

Prevalence of Apical Periodontitis in Different Communities: A Meta-Analysis.

Introduction: The aim of this study was to perform a meta-analysis on the prevalence of apical periodontitis (AP) in different communities to obtain accurate data on its prevalence. Methods and Materials: The prevalence of AP in different communities based on the number of individuals, teeth and root-filled teeth was searched using electronic databases of ISI Web of Knowledge, PubMed, Scopus and also ProQuest and Springer. The Metaprop meta-analysis was done using the software R version 3.3.0 with Meta package. The Logit transformation method and random-effects model were used to calculate the pooled prevalence. Heterogeneity was tested by the Q-test (P<0.1 represented statistical significance), I2 statistics (25%, 50% and 75% represented low, medium and high heterogeneity, respectively) and 2τ (2τ was calculated by DerSimonian-Laird estimator method). Results: A total of 77 studies were identified to qualify for inclusion into this meta-analysis. The prevalence of AP based on the number of individuals, teeth and root-filled teeth with the pooled prevalence was 0.519, 0.0498 and 0.3828, respectively. Conclusions: The results of the present study can be helpful for policy makers to monitor the dental public health demographically and compare it to other communities; they may be able find the strengths and drawbacks of their oral and dental health program.

Anesthetic Efficacy of Articaine and Ketamine for Inferior Alveolar Nerve Block in Symptomatic Irreversible Pulpitis: A Prospective Randomized Double-Blind Study.

INTRODUCTION: The aim of this prospective, randomized, double-blind study was to investigate the effect of articaine combined with ketamine on the success rate of inferior alveolar nerve block (IANB) in posterior mandible teeth with symptomatic irreversible pulpitis. METHODS AND MATERIALS: Forty two adult patients with diagnosis of symptomatic irreversible pulpitis of a mandibular posterior tooth were selected. The patients received two cartridges of either containing 3.2 mL 4% articaine with epinephrine 1:200000 and 0.4 mL 50 mg/mL ketamine hydrochloride (A-ketamine group) or 3.2 mL 4% articaine with epinephrine 1:200000 and 0.4 mL normal saline (A-saline group) using conventional IANB injections. Access cavity preparation started 15 min after injection. Lip numbness was required for all the patients. Success was considered as no or mild pain on the basis of Heft-Parker visual analog scale recordings upon access cavity preparation or initial instrumentation. Data were analyzed by independent student t, Mann-Whitney and Chi-square tests. RESULTS: The success rates were 55% and 42.9% for A-ketamine and A-saline group, respectively, with no significant differences between the two groups (P=0.437). CONCLUSION: Adding 0.4 mL 50 mg/mL ketamine hydrochloride to the articaine local anesthetic did not increase the efficacy of IANB for posterior mandibular teeth with symptomatic irreversible pulpitis.

Comparative evaluation of root canal morphology of mandibular premolars using clearing and cone beam computed tomography.

BACKGROUND: Different techniques are used to evaluate the anatomy of root canal system. The present study was aimed to evaluate the root canal morphology of mandibular premolars using clearing and cone beam computed tomography (CBCT) techniques. MATERIALS AND METHODS: A total of 182 mandibular first and second premolars were evaluated in vitro using 100 µm CBCT cross sections. The root canal morphology of the teeth was determined based on Vertucci classification in relation to the prevalence of C-shaped canals, lateral canals, and furcation location. Having removed the pulp tissue with NaOCl solution and staining the root canals with India ink, the samples were decalcified with 5% nitric acid and dehydrated with isopropyl alcohol. Finally, the samples were cleared with methyl salicylate. Data were analyzed by SPSS 16 software using McNamara, t-test, and Kappa coefficient. RESULTS: After Type I, the most frequent morphologies in both first and second premolars were Type V followed by Type IV. The prevalence rates of C-shaped morphology in first premolars using clearing and CBCT were 4.4% and 6.6%, respectively. However, no C-shaped morphology was found in second premolars. The maximum and minimum levels of agreement between the two techniques were observed in Type IV and Type V root canal morphologies, respectively. Extra root canals were identified in 25% and 13% of the first and second premolars, respectively. CONCLUSION: CBCT showed a higher accuracy in determining C-shaped root canal morphology than the clearing technique. It also showed the least accuracy in diagnosing lateral root canals.

Root Morphology and Canal Configuration of First and Second Maxillary Molars in a Selected Iranian Population: A Cone-Beam Computed Tomography Evaluation.

INTRODUCTION: The aim of this investigation was to evaluate root canal morphology of maxillary first and second molars and also to assess the prevalence and morphology of the second mesiobuccal canal (MB2) in these teeth, using cone-beam computed tomography (CBCT). METHODS AND MATERIALS: In this cross-sectional study, the total of 470 CBCT images from the archive of Radiology Department of Isfahan University of Medical Sciences (IUMS), Iran, was evaluated and 295 images were selected. The number of roots, and canal configuration were determined based on Vertucci's classification system. The data was analyzed using SPSS 20, and P-values less than 0.05 were considered significant. RESULTS: A total of 295 images from 295 patients (165 females and 130 males), including 389 maxillary first (197 right and 192 left) and 460 maxillary second (235 right and 225 left) molars were evaluated. The prevalence of MB2 canals were 70.2% and 43.4% in the maxillary first and second molars, respectively. The most common type of Vertucci's classification was type II (53.1%), followed by type I. CONCLUSION: The second mesiobuccal canal was present in almost two thirds of first and less than half of second molars. The morphology and canal configuration of a maxillary molar can almost predict the morphology of contralateral molar. However, it does not relate to the ipsilateral molar.

Effect of type of luting agents on stress distribution in the bone surrounding implants supporting a three-unit fixed dental prosthesis: 3D finite element analysis.

BACKGROUND: Osseointegration of dental implants is influenced by many biomechanical factors that may be related to stress distribution. The aim of this study was to evaluate the effect of type of luting agent on stress distribution in the bone surrounding implants, which support a three-unit fixed dental prosthesis (FDP) using finite element (FE) analysis. MATERIALS AND METHODS: A 3D FE model of a three-unit FDP was designed replacing the maxillary first molar with maxillary second premolar and second molar as the abutments using CATIA V5R18 software and analyzed with ABAQUS/CAE 6.6 version. The model was consisted of 465108 nodes and 86296 elements and the luting agent thickness was considered 25 µm. Three load conditions were applied on eight points in each functional cusp in horizontal (57.0 N), vertical (200.0 N) and oblique (400.0 N, θ = 120°) directions. Five different luting agents were evaluated. All materials were assumed to be linear elastic, homogeneous, time independent and isotropic. RESULTS: For all luting agent types, the stress distribution pattern in the cortical bone, connectors, implant and abutment regions was almost uniform among the three loads. Furthermore, the maximum von Mises stress of the cortical bone was at the palatal side of second premolar. Likewise, the maximum von Mises stress in the connector region was in the top and bottom of this part. CONCLUSION: Luting agents transfer the load to cortical bone and different types of luting agents do not affect the pattern of load transfer.

Maxillary repositioning according to Frankfort horizontal plane during orthognathic surgery.

CONTEXT: There are a lot of disagreements among surgeons over controlling the maxillary position during orthognathic surgery. AIM: To investigate maxillary repositioning according to Frankfort horizontal plane in orthognathic surgery. MATERIALS AND METHODS: Fourteen patients were selected who were submitted to maxillary or bimaxillary surgery. Maxillary model surgery was performed based on the treatment planning and an intermediate splint was made. The surgical technique in this study was based on maxillary osteotomy according to the findings of the model surgery, in a manner that the osteotomy line was parallel to the Frankfort horizontal plane. Intermediate splint was used for repositioning of the maxilla in the new position and the vertical position of that was determined according to external reference point and fixed on this position. The upper central incisor designed from prediction tracing and post-operative cephalometry on the first tracing. The new position of maxilla was evaluated horizontally and vertically. STATISTICAL ANALYSIS USED: A paired t-test was used to compare the predicted maxillary position and the actual position. Association between these two groups of variables was evaluated with Pearson correlation. RESULTS: The mean difference between the maxillary planned position and post-operative cephalometric radiography varied between 0.3 mm and 0.9 mm vertically (P value = 0.315) and 0.0 mm and 0.9 mm horizontally (P value = 0.034). The averages of horizontally and vertically observed changes were 0.3 mm and 0.17 mm respectively (P < 0.001). CONCLUSION: Good surgical accuracy in repositioning of the maxilla can be achieved according to Frankfort horizontal plane during the surgery. By eliminating the ramping effect the accuracy of surgery increases.

X-tip intraosseous injection system as a primary anesthesia for irreversible pulpitis of posterior mandibular teeth: A randomized clinical trail.

BACKGROUND: Successful anesthesia during root canal therapy may be difficult to obtain. Intraosseous injection significantly improves anesthesia's success as a supplemental pulpal anesthesia, particularly in cases of irreversible pulpitis. The aim of this study was to compare the efficacy of X-tip intraosseous injection and inferior alveolar nerve (IAN) block in primary anesthesia for mandibular posterior teeth with irreversible pulpitis. MATERIALS AND METHODS: Forty emergency patients with an irreversible pulpitis of mandibular posterior teeth were randomly assigned to receive either intraosseous injection using the X-tip intraosseous injection system or IAN block as the primary injection method for pulpal anesthesia. Pulpal anesthesia was evaluated using an electric pulp tester and endo ice at 5-min intervals for 15 min. Anesthesia's success or failure rates were recorded and analyzed using SPSS version 12 statistical software. Success or failure rates were compared using a Fisher's exact test, and the time duration for the onset of anesthesia was compared using Mann-Whitney U test. P < 0.05 was considered significant. RESULTS: Intraosseous injection system resulted in successful anesthesia in 17 out of 20 patients (85%). Successful anesthesia was achieved with the IAN block in 14 out of 20 patients (70%). However, the difference (15%) was not statistically significant (P = 0.2). CONCLUSION: Considering the relatively expensive armamentarium, probability of penetrator separation, temporary tachycardia, and possibility of damage to root during drilling, the authors do not suggest intraosseous injection as a suitable primary technique.