Successful management of pain during endodontic treatment is essential for both patients and dentists. Achieving adequate pulp anesthesia in mandibular molars is a significant concern for patients with irreversible pulpitis during endodontic treatment. The increased sensitization of nociceptors due to inflammation decreases the success of inferior alveolar nerve block (IANB). The main focus is on reducing inflammation before delivery of local anesthesia to increase the success of anesthetic drugs. This umbrella review aimed to revise, qualify and summarize the existing body of evidence on the effect of premedication on IANB in patients with irreversible pulpitis. A literature search was conducted using electronic databases (PubMed, Scopus, the Web of Science, and the Cochrane Library) with no date restriction until September 2021 to identify the relevant studies. All the cross-references of the selected studies and grey literature were also screened. Four systematic reviews assessing the effect of premedication on the success of IANB were selected. A conclusion was drawn that premedication with >400 mg of ibuprofen can positively affect the success of IANB.

Background: An ever-increasing demand is seen for clear aligners and transparent vacuum-formed retainers. They are esthetic and convenient. However, the biomaterials used in these appliances might pose biological safety and biocompatibility threats in terms of their bisphenol-A (BPA) release, cytotoxicity, adverse effects, and estrogenic effects. Due to the controversial results and the lack of any systematic reviews in this regard, we conducted this systematic review. Materials and Methods: Web of Science, PubMed, Cochrane, Scopus, and Google Scholar as well as references of the found articles were searched (independently by 3 researchers) up to December 22, 2021, to find studies relevant to the biocompatibility of clear aligners and thermoplastic retainers. The search keywords were a combination of the following (and more): Essix, vacuum-formed aligner, thermoplastic aligner, clear aligner, Invisalign, vacuum-formed retainer, BPA release, monomer release, cytotoxicity, estrogenicity, biocompatibility, chemical properties, and oral epithelial cell. As eligibility criteria, articles in all languages would be included as long as their text could be translated clearly using online translators or by professional translators; all types of publications (article, book, and thesis) would be included if containing relevant studies and information; they should have been on clear liners or thermoplastic retainers; and they should have been on biocompatibility, safety, cytotoxicity, or estrogenicity of clear aligners or thermoplastic retainers. There were no restrictions on the type of study (randomized clinical trials, experimental in vitro studies). Studies focusing merely on the mechanical properties of clear aligners or thermoplastic retainers (without examining their chemical properties) would be excluded. The risk of bias was assessed. Results: The risk of bias was rather low. However, the methodologies of the studies were quite different. Overall, 16 articles (1 randomized clinical trial and 15 in vitro studies) were identified. The data for BPA release were reported in four articles (1 clinical trial and 3 in vitro studies). Quantitatively speaking, the amount of released BPA reported by in vitro studies was very low, if not zero. However, the BPA level was very high in the only randomized clinical trial. Many adverse effects were linked to using clear aligners or transparent retainers, including pain and soft-tissue issues such as burning, tingling, sore tongue, lip swelling, blisters, ulceration, dry mouth, periodontal problems, and even systemic problems such as difficulty in breathing. Besides these biological adverse effects, oral dysfunctions and speech difficulties and tooth damage may be associated with clear aligners and should as well be taken into consideration. Conclusion: Given the very high levels of BPA leach observed in the only clinical trial and considering other possible dangers of small traces of BPA (even at low doses) and also given the numerous adverse events linked to clear aligners or transparent retainers, it seems that safety of these appliances might be questionable and more clinical studies of biocompatibility are needed in this regard.

Background: Different studies about the effects of mouthwashes on force reduction by elastomeric chains are reported in the literature. Hence, this review was done for the assessment of force degradation in the elastomeric chains in different mouthwash compositions. This study helps to improve the clinical performance of elastomeric chains used in orthodontics, reducing force degradation, and finally assisting clinicians in choosing better and more efficient methods for their treatments. Materials and Methods: In this review article, an extensive search was performed in the electronic databases of Cochrane Library, Web of Science, PubMed, and Scopus from the year 1990–2020. No language restriction was considered and manually investigated the reference lists of all articles related to the title. Out of 450 obtained articles, 14 in vitro studies were chosen based on the inclusion criteria, and their quality was assessed using modified CONSORT. This systematic review was limited and written based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Results: Based on the results achieved, mouthwashes containing alcohol caused considerable force degradation in the elastomeric chains compared to the alcohol-free ones and mouthwashes with fluoride caused lesser force degradation compared to other types.

Background: The burden of oral diseases is increasing, which constitute a major public health problem. The use of probiotics as an adjuvant, along with routine dental care practice by an individual, can produce additional benefits in the maintenance of one's oral health. The study aimed to investigate the effect of Bifidobacterium as a probiotic on oral health. Material and Methods: Six databases and registers were searched from the start of the database to December 2021 without any restrictions. Randomized controlled trials (RCTs) evaluating the clinical effects of Bifidobacterium as a probiotic on oral health were included in the study. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed to conduct this systematic review. The included studies were analyzed for the risk of bias using the Cochrane risk-of-bias tool for randomized trial (RoB 2) tool as well as quality of available evidence using GRADE criteria. Results: From the 22 qualified studies, four studies showed non-significant results. There was a high risk of bias in 13 studies and some concerns of bias in nine studies. No adverse effects were reported, and the quality of available evidence was moderate. Conclusion: The effect of Bifidobacterium on oral health is questionable. Further high-quality RCTs are required on the clinical effects of bifidobacteria and also the optimum level of probiotic needed, and ideal mode of administration to provide oral health benefits. Furthermore, synergistic effects of the combined use of various strains of probiotics need to be studied.

Background: Dentistry practice has become more complex and challenging in the recent years. The clinical decision-making process has experienced many problems due to changing socioeconomic patterns, knowledgeable patients, rapid technological advances, and information explosion. The present study reviewed the status of the attitude toward evidence-based dentistry (EBD) among dental students of Iran Universities. The effect of the educational intervention was also assessed. Materials and Methods: This systematic review was conducted according to the Preferred Reporting Items for Systematic review and Meta-Analysis checklist. Search strategy was developed by Medical Subject Headings terms and keywords surfing electronic available databases including Medline/PubMed and Google Scholar and local databases such as Scientific Information Database (SID) and Magiran. Two reviewers read the abstracts of all eligible papers and excluded the duplicates. They extracted the information of the full-text of the studies included in the review and assessed the quality by Joanna Briggs Institute critical appraisal checklist. Results: Ten studies including 8 cross-sectional and 2 interventional studies met the criteria. The assessment of the attitude of 937 dental students from a different region of the country toward EBD showed moderate to acceptable status using 3 different tools. In regard to educational interventions, 2 studies were successful to improve their attitude. Conclusion: Although the researchers presented good scores on the attitude questionnaires, the quality of the study tools, the eligible criteria for recruiting the participants and the method of evaluating the construct of attitude should be investigated in future studies.

Background: During the orthodontic bonding process, the need for repositioning or rebonding of orthodontic brackets on the enamel surface occurs frequently. The aim of this study is to compare the shear bond strength (SBS) in rebonding orthodontic stainless steel brackets with three different methods of enamel surface conditioning methods. Materials and Methods: In this in vitro study, 80 human premolars that were extracted for orthodontic purposes were randomly divided into four groups and underwent orthodontic bonding procedure (N = 20). Except for the control group, three other groups underwent debonding and rebonding process in which after removing the remaining adhesive with tungsten-carbide bur, enamel surface conditioned by three different methods including re-etching with phosphoric acid, sandblasting + acid etching, and Erbium-doped Yttrium–Aluminum–Garnet laser. Then, the SBS of the bracket to the enamel surface was compared between different groups. Scanning Electron microscopy images were also obtained from a number of samples. Statistical analysis was performed by Kruskal–Wallis and Mann–Whitney tests. Results: The highest SBS was observed in the primary bond (control group) with an average of 29,440 MPa. There was a significant difference between the studied groups (P < 0.001) and only the group that was re-etched with phosphoric acid had no significant difference with the control group (P = 0.708) ∝ =0.05. Conclusion: Rebonding of brackets using phosphoric acid for reconditioning of the enamel surface creates bond strength comparable to the primary bond. Other groups had significantly lower SBS than the control group.

Background: Periodontitis, the second most common reason for tooth loss in adults, is a chronic inflammatory condition that increases the prevalence of cancer by inhibiting apoptosis and promoting tumor cell growth. However, it is still debatable if tooth loss is an important risk factor in oral cancer (OC). The aim of this systematic review is to analyze the relationship between tooth loss and the probability of developing head-and-neck cancer and also to see if there is an association between tooth loss, periodontitis, and the risk of OC. Materials and Methods: Studies that depicted a link between tooth loss and OC (till 2017) were searched from online databases accompanied by a thorough manual search of relevant journals. Data were collected from eligible studies, and meta-analysis was carried out using the Meta-Analysis software. The effect of various inclusions was assessed by sensitivity and subgroup analysis. Publication bias was also evaluated. Results: The meta-analysis consisted of 15 publications. When the number of teeth lost was counted, there was significant variability (I2 = 98.7%, P = 0.0001). When more than 15 teeth were missing in a subgroup analysis, there was a 2.4 times greater risk of OC (odds ratio: 2.496, 95% confidence interval [CI] = 2.067–3.015, P = 0.001) with no heterogeneity (I2 = 0.00%, 95% CI for I2 = 0.00–68.98). Subgroup analysis revealed that there was no evidence of publication bias. Conclusion: It was concluded that tooth loss can increase the OC risk by nearly 2 folds. However, large-scale population-based studies are needed to substantiate the findings.