Background: In December 2019, a series of unusual pneumonia has been reported in Wuhan, China. This pneumonia was related to beta-coronavirus cluster which was named COVID-19. The aim of this study is to review the published paper on COVID-19 protections guide lines and attempt to summarize different suggested guide lines in order to help dental/oral healthcare to have better protection against COVID -19 Materials and Methods: An electronic literature search was conducted via google scholar, PubMed, and dental associations' of different countries' website using the key word “COVID-19, Dental team, Guide lines and Recommendation”.A total of seven guidelines were found suitable to be included in this review. Conclusion: Individuals with 'possible' or 'confirmed' COVID-19 should not be seen for routine dental care. Multi-step approach should begin before the patient arrives on the office and includes guidance regarding their arrival and it should be completed duration of the affected patient's presence in the practice. Accurate travel history, fever or history of fever, acute respiratory infection and severe respiratory infection without fever requiring hospitalization should be checked by staff via patients telephoning to make an appointment and finally the primary infection control goal is to prevent transmission of disease. These treatment guidelines are based on very limited evidence from the literature and should be revised as soon as more evidence about the infection control advices for dental team regarding COVID-19.

Tricho–dento–osseous (TDO) syndrome is a multisystem congenital disorder that is known by bone, skin, and hair abnormalities. Primitive studies show different varieties of manifestations related to this disorder, which involve sclerotic bones, nail involvement, enamel hypoplasia, mandibular prognathism, and taurodontism. Although exploring different TDO cases revealed genetic mutations in all of them, they have many variations in phenotypic view. In this study, we report a case whose primary diagnosis was alopecia and came for extraction of her third molars, but after clinical and radiographic examination, it was found that the cause of her disease was something different.

Background: Interaction between 2% lidocaine HCl (with and without adrenaline) and sodium hypochlorite (NaOCl) resulted in a toxic precipitate formation. The aim of this in vitro study was to assess the interaction between 4% articaine hydrochloride with adrenaline (AHa) and commonly used endodontic irrigants 3% NaOCl, 2% chlorhexidine (CHX), and 17% ethylenediaminetetraacetic acid (EDTA) using spectroscopic analyses. Materials and Methods: In this in vitro study, 3% NaOCl, 2% CHX, and 17% EDTA were mixed with 4% AHa individually. 1.7 ml of 4% AHa from the cartridge was mixed with 1.7 ml of each test irrigants. The solutions were subjected to a preliminary ultraviolet spectroscopic (UVS) analysis to assess forpotential interactions (if any). If the interaction was detected, the test solutions were further subjected to nuclear magnetic resonance (NMR) analysis for characterization. The precipitate formed (if any) was then subjected to NMR analysis. Results: UVS analysis revealed a bathochromic shift when 3% NaOCl and 2% CHX were mixed with 4% AHa, respectively. This shift was not observed when EDTA was mixed with 4% AHa. 1H and 13C NMR spectra confirmed the interaction between 3% NaOCl with 4% AHa, which resulted in a precipitate formation, methyl 3-amino-4-methylthiophene-2-carboxylate (MAMC). The analysis of 1H NMR spectra showed peaks at 7.1 ppm, 2.21 ppm, and 9.93 ppm, respectively, which corresponds to aromatic ring protons. A peak at 3.8 ppm was assigned to methyl proton of methyl ester. The characteristic appearance of peaks at 14.82 and 51.16 ppm corresponds to aliphatic carbons. The five peaks occurring at 126, 134.5, 139.2, 156.5, and 162.9 ppm correspond to the aromatic carbon atoms present in the thiophene unit. NMR spectra revealed no interaction between 2% CHX and 4% AHa. 1H and 13C NMR spectra confirmed that 3% NaOCl interacted with 4% AHa, leading to the formation of a precipitate MAMC. Conclusion: 3% NaOCl interacted with 4% AHa leading to the formation of a precipitate MAMC which is reported to exhibit the least toxicity. Until the precipitate is studied further, it would be advisable to avoid the immediate use of NaOCl following administration of intrapulpal anesthetic solution with articaine hydrochloride (with adrenaline).

Background: The etiology of temporomandibular disorders (TMDs) is complex and associated with multiple predisposing and initiating factors. Articular eminence morphology and steep eminence inclination have been postulated as the etiological factors, but there has been no clear evidence of association of morphology of the temporomandibular joints (TMJ) complex as a probable predisposing factor in the pathogenesis of TMDs. Materials and Methods: This was a cross-sectional, case–control study, and cone-beam computed tomography scans, and the evaluation was performed for 60 joints in 30 patients with symptomatic TMDs and for 40 healthy joints of 20 age-matched patients. One-way ANOVA, post hoc, unpaired t-test, Chi-square, and intra-class correlation coefficient test were used to determine the correlation between the TMJ articular eminence inclination, height, condylar bone changes, condyle, and fossa shapes with symptomatic TMDs. The P < 0.05 were considered statistically significant. Results: There was a statistically significant difference of articular eminence inclination and height with a steeper eminence inclination in the control group (P = 0.044*, and 0.035*). The condylar bone changes were found to be significantly more in the TMJ disorder group (P = 0.001*). There was no significant association of condyle and fossa shapes (P = 0.482 and 0.689) and of articular eminence inclination and height with condylar bone changes (P = 0.695, 0.498, 0.192, and 0.823) and condyle shapes (P = 0.389, 0.521, 0.260, and 0.387). The eminence inclination was not associated with fossa shapes (P = 0.471 and 0.086), but eminence height was associated with fossa shapes in the TMJ disorder group (P = 0.043* and 0.111). Conclusion: The results depicted that there was no significant association between TMJ complex anatomy and TMJ disorders in the present study population.

The aim of this work is to describe a case of severe disparallelism between two implants supporting a cement-retained bridge, placed in the maxilla, employing two custom-angled abutments. Fractured abutment screw and fractured abutment involved two implant restorations in the maxilla. Once prosthetic components have been removed, a new prosthetic rehabilitation has been planned. The divergence between the implants was measured, obtaining an angle of divergence of 39°. Then, two custom-angled titanium abutments and two metal-ceramic splinted crowns were realized.

Background: Recently, inequality in dental care has become increasingly popular in both developed and developing countries as a matter of health policy. Thus, the aims of this study were examining inequality in dental care expenditures and assessing the effects of insurance coverage and other variables on these services. Materials and Methods: In this cross-sectional and descriptive-analytical study, we used secondary data of the National Health Accounts that has been conducted in 2008 in Iran. The sample size was 17,239 households in all over the country. All analyses were performed by Stata software using Mann–Whitney test and logistic regression. P < 0.05 was considered statistically significant. To determine inequality in dental services, the concentration index (CI) was used. Results: CI for total dental expenditures was 0.315 and for orthodontics was 0.6. Findings showed that out-of-pocket expenditure for dental care was progressive and there was a significant relationship between total dental expenditure with residence areas (odds ratio [OR] =1.3; P > 0.001), complementary insurance coverage (OR = 1.3; P > 0.001), family size (OR = 1.46; P > 0.001), and income (OR = 1.3; P > 0.001). Conclusion: Dental expenditures were progressive in Iran, and the rich have paid more share for these services. It seems that implementing insurance programs, changes in the financing of dental care, development of insurance basic benefits package, supporting programs for the poor, adopting educational policies, and promoting oral health for vulnerable people can have an effective role in decreasing inequality in using dental services.

Background: Cryogenic methods have been used to increase the wear, abrasion, corrosion resistance and to improve the strength of metals. The aim of this study was to evaluate the effect of cryogenic treatment on the cyclic fatigue resistance of rotary nickel-titanium (NiTi) instruments. Materials and Methods: In this in vitro study, 20 Hyflex (Coltene, Altstätten, Switzerland) nickel-titanium instruments, size 25, 0.06 taper, were randomly divided into two groups as follows: untreated NiTi rotary files (Group A) and cryotreated NiTi rotary files (Group B). The instruments of Group A were completely immersed in a cryocan containing liquid nitrogen (–196°C) for 24 h. After 24 h, the instruments were removed from the bath and were allowed to return to room temperature gradually. All files were used (at a speed of 500 rpm and a torque of 2.5 Ncm) in an artificial canal with a 60° curvature until fracture. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture (NCF). Groups were compared using the independent-samples t-test. The level of statistical significance was set at 0.05. Results: Mean NFCs in Group A and B were 1576 and 1395, respectively. However, statistical analysis showed that there was no significant difference between the groups (P = 0.2). Conclusion: Deep cryotherapy of NiTi endodontic files cannot improve the cyclic fatigue resistance of HyFlex files, but further studies are required to evaluate these cryogenically treated NiTi files clinically.

Background: Light curing of resin composite is associated with a thermal rise that may have harmful effect on the health of the vital pulp. In addition, desirable polymerization is important to achieve mechanical properties and clinical function. The purpose of this in-vitro study was to compare the thermal rise under normal dentin during photopolymerization and degree of conversion (DC) of bulk fill and conventional resin composite using continuous high- and soft-start mode. Materials and Methods: In this in-vitro study, Cl I cavities with a dimension of 4 mm × 4 mm × 4 mm and remaining dentin thickness of 1 mm were prepared on 56 extracted human molars. The temperature rise during the light curing of conventional resin composite (Tetric N Ceram, Ivoclar Vivadent) by incremental filling technique and bulk-fill resin composite (Tetric N Ceram Bulk Fill, Ivoclar Vivadent) by bulk-filling technique were measured with a K-type thermocouple wire. DC of both resin composites was measured using Fourier-transform infrared spectroscopy. Data were analyzed using one-way ANOVA, Tamhane and Duncan post hoc, two-way ANOVA at the significance level of α = 0.05. Results: Photopolymerization temperature rise due to soft start mode and the first layer of conventional composite was higher than continuous high mode and bulk-filling technique, respectively (P < 0.001). DC of conventional resin composite was higher than bulk-fill composite (P < 0.001). Conclusion: Soft-start mode produced higher thermal rise than continuous high mode and conventional resin composite showed higher DC than bulk-fill composite.

Background: Gutta-percha has been the predominant root canal filling material which is developed with different taper. Canal obturation fixed with nickel–titanium (NiTi) instruments and tapered gutta-percha master cone and lateral condensation is advantageous because it is clinically effectual and appears to result in a radiographically acceptable outcome. The aim of this in vitro study was to determine the effect of tapered master gutta-percha cone on apical seal of straight and curved root canals using NiTi rotary files. Materials and Methods: In this in vitro study total of 130 mandibular molars were selected and divided into six experimental groups (n = 20) based on the degree of root canal curvatures (0°–20°and 20°–40°) and the taper of master cones (0.02, 0.04, and 0.06). The roots were immersed in the bacterial leakage model and monitored daily for a period of 70 days. Data were analyzed using Kaplan–Meier approach, log-rank test, and Chi-square tests. P < 0.05 was considered statistically significant. Results: The microleakage in the 0°–20° canal curvature using 0.02- and 0.04-tapered master cones was similar and considerably <0.06-tapered master cone (P < 0.05). However, the microleakage in the 20°–40° canal curvature using 0.02- and 0.04-tapered master cones was more than 0°–20° and for 0.06-tapered master cone was <0°–20°, but there was no statistical difference between the use of 0.02-, 0.04-, and 0.06-tapered master cones (P > 0.05). Conclusion: The lateral condensation filling technique using 0.02- and 0.04-tapered master cones is more effective in minimizing microbial leakage in straight canals than 0.06-tapered master cone.

Background: Regarding the prevalence and importance of periodontal disease and the potential of salivary biomarkers for the early diagnosis of these diseases, this study was conducted to compare salivary concentrations of Interleukin-17 (IL-17) and Interleukin-18 (IL-18) in patients with chronic periodontitis and healthy individuals. Materials and Methods: The present research was a descriptive–analytical and also a cross-sectional study. Unstimulated saliva with full-mouth clinical periodontal recordings were obtained from 20 healthy individuals and 20 individuals with chronic periodontitis. The concentrations of salivary IL-17 and IL-18 were determined using the enzyme-linked immunosorbent assays. The nonparametric Mann–Whitney U-test was used for statistical analysis of the findings. Alpha level was set at 0.05. Results: The mean salivary concentration of IL-18 in patients with chronic periodontitis was 143.10 pg/mL, which was higher than the same concentration in healthy controls (78.33 pg/mL), (P = 0.035). The mean salivary concentration of IL-17 in patients with chronic periodontitis and healthy controls was 3.51 and 4.57 pg/mL, respectively, and there was no difference between the two groups (P = 0.283). Conclusion: Within the limitations of the present study, it may be suggested that an elevated salivary IL-18 level in chronic periodontitis patients has the potential to be a biomarker for periodontal tissue destruction.

Background: This in vitro study was conducted to compare the effect of universal bonding application strategy (i.e., self-etch and etch-and-rinse) on marginal adaptation of bulk-fill and conventional composite resins in Class II restorations. Materials and Methods: In this in vitro study sixty sound premolars extracted for orthodontic reasons were selected. The samples were allocated to four groups based on the universal bonding application strategy (self-etch and etch and rinse) and type of composite (bulk-fill and conventional). In each group, boxes were prepared with a depth of 4 mm on the mesial surfaces. Finally, the marginal adaptation of the samples was evaluated under a stereomicroscope. Two-way ANOVA was used to compare the marginal adaptation data in the study. Statistical significance was set at P < 0.05. Results: Considering the type of universal bonding application strategy, there was a statistically significant difference in marginal adaptation. Etch-and-rinse strategy showed better marginal adaptation compared to self-etch strategy (P < 0.001). However, there was no statistically significant difference in marginal adaptation between the two composite resins (P = 0.829). Furthermore, the interaction between the two factors (type of universal bonding application strategy and type of composite resin) was not statistically significant (P = 0.629). Conclusion: Etch-and-rinse bonding application strategy in both the bulk-fill and conventional composite resins exhibited better marginal adaptation compared to self-etch bonding application strategy. However, the difference of marginal adaptation between the two types of composite resins (bulk and conventional) was not significant.

Background: Two-dimensional intraoral radiography is the most common tool for recognizing root fractures. Improving the quality of images by means of enhancement tools can increase the recognition power of them. The aim of this study is to evaluate the effect of digital image enhancement on vertical and horizontal root fractures (HRFs) diagnostic accuracy. Materials and Methods: In this in vitro study, 100 human extracted teeth, involving 50 mandibular premolars and 50 maxillary incisors, were investigated. In total, 25 premolar teeth were vertically fractured and other 25 sound teeth served as testing group. According to the verified methods, 25 incisor teeth were fractured and other 25 teeth of this group served as testing ones. Following, by using the charge-coupled device sensor, preapical digital images were recorded. The original images were altered using reverse-contrast and colorization enhancement tools. Two different observers independently investigated all of the images. Receiver operating characteristic analysis was used to calculate the area under the curve (AUC) and sensitivity and specificity of all images. Data analyzde using receiver operating characteristic (ROC) analysis. Two-ways variance analysis was used to assess differences in the values (P = 0.05 ). Results: AUC and sensitivity and specificity related to the original, reverse-contrast, and colorized images were calculated (0.84, 0.64, 0.99), (0.84, 0.64, 0.96), and (0.82, 0.64, 0.92) respectively, for vertically root fractured images. AUC and sensitivity and specificity related to the original, reverse-contrast, and colorized images were calculated (0.49, 0.44, 0.56), (0.50, 0.44, 0.60), and (0.48, 0.48, 0.48), respectively, for horizontally root-fractured images. Conclusion: The results of the present study revealed that reverse-contrast and colorized enhancement filters cannot be used as critical methods in detecting in vitro vertical and HRF.

Background: Results on the strength and displacement of internal fixation methods for bilateral sagittal split ramus osteotomy are controversial, and some designs have not been adequately studied. Therefore, this study was conducted to compare techniques using bicortical or monocortical screws. Materials and Methods: In this in vitro study, 35 sheep hemi-mandibles were randomly assigned to five groups of seven each: fixation using (1) a 13 × 2 screw, (2) two 13 × 2 screws (arranged vertically), (3) three 13 × 2 screws, (4) 1 plate with 4 holes and four monocortical screws, and (5) a Y-shaped plate and five monocortical screws. Specimens underwent vertical forces until failure. Breakage forces and displacements of groups were recorded and compared statistically. Using one-way analysis of variance (ANOVA) with a Tukey's post hoc test and Kruskal–Wallis test. Level of significance was predetermined as 0.05. Results: Strengths of Groups 1–5 were, respectively, 14.43 ± 4.35, 28.00 ± 8.89, 28.29 ± 8.01, 29.43 ± 8.24, and 61.29 ± 12.38 N, respectively (P = 0.000, analysis of variance). The corresponding displacement extents were 7.98 ± 0.04, 7.85 ± 0.26, 8.00 ± 0.00, 7.35 ± 1.73, and 6.79 ± 2.03 mm (P = 0.298, Kruskal–Wallis test). Conclusion: Use of a single bicortical screw is the weakest method, while Y-shaped plates might provide the highest strength. Using two or three bicortical screws or 4-hole plates might deliver similar strengths.

Background: The ideal maxillofacial prosthesis should have fine and thin boundaries that bind with the surrounding facial structures and possess high tear strength. This study aims to determine the best percentages of nanofiller (TiO₂) and intrinsic pigment (silicone functional intrinsic) that could be mixed in as additives to improve the tear strength of Cosmesil M511 and VST50F silicone elastomers with the least effect on their hardness. Materials and Methods: In this in vitro experimental study, a total of 80 samples, 40 for each elastomer, were fabricated. Each elastomer sample was split into two equal groups to test for tear strength and Shore A hardness. Each group consisted of 20 samples, including 10 control samples without additives and 10 experimental samples with additives (mixtures of 0.2 wt% nano-TiO₂ + 0.25 wt% intrinsic pigment and 0.25 wt% nano-TiO₂ +0.25 wt% intrinsic pigment for the Cosmesil M511 and VST50F silicone elastomers, respectively). Two-way ANOVA and Tukey test were used for comparison; P < 0.05 was considered statistically significant. Results: Significant differences in tear strength were found among all tested groups (P < 0.05). The tear strength of the experimental subgroups significantly increased compared with the control subgroups (P < 0.05). Significant differences in Shore A hardness were also observed among all tested groups (P < 0.05) except between the experimental subgroups of both materials, where a nonsignificant difference was obtained (P > 0.05). Conclusion: Incorporation of select percentages of TiO₂nanofiller and intrinsic pigment into Cosmesil M511 and VST50F silicone elastomers yields improvements in tear strength with a slight increase in hardness.

Background: Post and core treatment is commonly performed for endodontically treated teeth to replace the lost tooth structure and reinforce and protect the remaining dental tissue. This study aimed to compare the effect of three-core building materials on fracture resistance of endodontically-treated teeth restored with fiber-reinforced composite (FRC) posts and ParaPosts. Materials and Methods: This in vitro, experimental study evaluated 108 sound, single-rooted mandibular first premolars extracted for orthodontic purposes. The teeth were randomly divided into nine groups (n = 12) of control (no endodontic or restorative treatment), FRC + Photo Core (Group 2), FRC + LuxaCore (Group 3), FRC + Core Max II with bonding agent (Group 4), FRC + Core Max II without bonding agent (Group 5), ParaPost + Photo Core (Group 6), ParaPost + LuxaCore (Group 7), ParaPost + Core Max II with bonding agent (Group 8), and ParaPost + Core Max II without bonding agent (Group 9). The fracture resistance was measured by applying the load at 45° angle relative to the longitudinal axis of the tooth with a crosshead speed of 1 mm/min using a universal testing machine. Data were through descriptive statistics, Tukey's test, and one-way analysis of variance (α = 0.05). Results: The mean fracture resistance was 454.0 ± 62.7, 410.8 ± 48.3, 365.1 ± 42.1, 423.7 ± 111.7, 392.4 ± 90.0, 292.3 ± 83.9, 242.3 ± 73.4, 278.2 ± 67.9, and 247.3 ± 49.6 N in Groups 1–9, respectively. Group 4 showed the highest fracture resistance, which was significantly higher than this study the value in all ParaPost and control groups (P < 0.05) but had no significant difference with the fracture resistance of other groups (P > 0.05). Conclusion: Fracture resistance is independent of the type of core building material used, and the tested products had no superiority over each other. The mean fracture resistance of FRC post groups were significantly higher than that of ParaPost groups. Furthermore, Core Max II + bonding agent yielded insignificantly higher fracture resistance than Core Max II without bonding agent.

Background: Scaling and root planing (SRP) for the treatment of periodontitis may be less effective in some patients. This study evaluated the effectiveness of local doxycycline as an adjunct to SRP among smokers with periodontitis compared to SRP alone in randomized controlled trials (RCTs). Materials and Methods: For this systematic review and meta-analysis, PubMed and Scopus databases were searched till November 2018 for English publications. RCTs that compared the effect of local doxycycline adjunct to SRP among smokers with periodontitis were selected. Patient characteristics, disease characteristics, and outcome data on clinical attachment level (CAL) and periodontal probing depth at 1, 3- and 6-month follow-up was extracted. Quality of selected studies was assessed by the revised Cochrane Risk of Bias 2.0 tool. Random effects model and trial sequential analysis were performed. GRADE approach was used to assess the quality of evidence. P > 0.05 was considered as statistically significant. Results: Five trials were included in the review. Local use of doxycycline as an adjunct to SRP was effective in gain of 1.1 mm (0.47–1.74, P = 0.091) in CAL at 6 months calculated from two studies. The evidence was of low quality, and at least a total of 866 patients are required for conclusiveness. Conclusion: Local doxycycline as an adjunct to SRP significantly improved clinical attachment in smokers with periodontitis and can be recommended. Studies are required with long-term follow-up and patient-related outcome data.

Background: Considering the increase in demand for orthodontic treatment in adults, bracket bond to restored teeth is a clinical challenge. This study sought to compare the shear bond strength (SBS) of orthodontic brackets to feldspathic porcelain using universal adhesive and conventional adhesive with and without silane application. Materials and Methods: In this in vitro study Fifty-six feldspathic porcelain discs were roughened by bur, and 9.6% hydrofluoric acid was used for surface preparation. Samples were divided into the following four groups (n = 14): Group 1: universal adhesive, Group 2: universal adhesive/silane, Group 3: conventional adhesive, and Group 4: conventional adhesive/silane. Mandibular central incisor brackets were bonded, and SBS was measured by Instron^® machine. To assess the mode of failure, adhesive remnant index (ARI) score was determined. The data were analyzed using SPSS software and two-way ANOVA, Bonferroni test, and Kruskal–Wallis test (P < 0.05 considered significant). Results: The highest SBS was noted in the universal adhesive/silane group (12.7 MP) followed by conventional adhesive/silane (11.9 MP), conventional adhesive without silane (7.6 MP), and universal adhesive without silane (4.4 MP). In the absence of silane, the conventional adhesive yielded significantly higher SBS than universal adhesive (P = 0.03). In the presence of silane, the two adhesives showed SBS values significantly higher than the values obtained when silane was not applied, while the two adhesives were not significantly different in terms of SBS in the presence of silane (P = 0.53). Based on ARI score, there were statistically significant differences between Groups 1 and 4 (P = 0.00) and Groups 2 and 4 (P = 0.023). Conclusion: Based on the current results, SBS of bracket to porcelain mainly depends on the use of silane rather than the type of adhesive. Both universal and conventional adhesives yield significantly higher SBS in the presence of silane compared to that in the absence of silane.