Background: Laser therapy, along with the use of fluoridated compounds is a novel technique suggested for caries prevention. Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) is another product suggested for this purpose. This study compared the effect of CPP-ACP and fluoride with/without Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser irradiation on enamel microhardness of permanent teeth. Materials and Methods: This in vitro experimental study evaluated 35 extracted third molars. The teeth were decoronated, and the crowns were split into buccal and lingual halves. The samples were randomly divided into seven groups (n = 10) of GC Tooth Mousse, MI Paste Plus, laser, fluoride varnish, laser + GC Tooth Mousse, laser + MI Paste Plus, and laser + fluoride varnish. The baseline microhardness was measured before the intervention. After the intervention, the samples were kept in artificial saliva for 1 h and were then immersed in the demineralizing solution for 3 h followed by 21 h of immersion in the remineralizing solution for a total period of 12 days. Finally, the teeth were kept in the remineralizing solution for 2 more days. The secondary microhardness of the teeth was then measured. Data were analyzed using the Shapiro–Wilk test, two-way ANOVA, and Tukey's Honestly Significant Difference test. Results: The fluoride varnish (14.31%) and laser + fluoride varnish (18.79%) groups experienced minimum reduction in microhardness, while the GC Tooth Mousse group experienced maximum reduction in microhardness (91.64%) (P < 0.001). Laser irradiation before the application of remineralizing agents increased the microhardness only in laser + GC Tooth Mousse group (P < 0.001). Conclusion: Fluoride varnish increased the enamel microhardness, while GC Tooth Mousse had no such effect. Laser therapy before the application of remineralizing agents did not significantly enhance enamel resistance to demineralization.

Background: This study aimed to evaluate the use of artificial teeth for endodontic training for dental students. Materials and Methods: The following aspects of the artificial teeth were approved by the endodontists in Isfahan University of Medical Science: internal and external anatomy; coronal pulp chambers regarding their size, shape, and canal path; the root canals regarding their size, shape, and position; filling the pulp chamber and root canals by considering the texture, quantity, color, and ease of handling; and resin hardness and visualization of the radiographic image. Results: The results showed favorable opinions regarding the internal and external anatomy, coronal pulp chamber, root canal (s), handling, and radiographic imaging. The contents of the pulp space and hardness of the teeth were satisfactory. Conclusion: The artificial teeth tested have the potential to replace the natural teeth in preclinical training.

Background: The aim of this study was to investigate whether boron nitride (BN) and BN–chromium (BN–Cr) coatings applied with the sputtering method would change the characteristics of hardness and discoloration of the ceramic veneer surface. Materials and Methods: In this experimental study, thirty disc-shaped cores (10 mm in diameter and 0.8 mm in thickness) were prepared. Three different ceramic systems, IPS Empress (E) (Ivoclar Vivadent, Schaan, Liechntenstein), IPS e.max Press (EP) (Ivoclar Vivadent, Schaan, Liechntenstein), and Turkom Cera (T) (Turcom-Ceramic SDN-BHD, Kuala Lumpur, Malaysia), were tested, each with n = 10. The specimens were divided into two subgroups (n = 5) according to the coating on the veneering ceramic: BN or BN–Cr. The Vickers hardness and color differences (ΔE) values were measured before and after coating. Surface analysis was performed with X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopic. The Wilcoxon signed-rank test was performed to compare hardness values. The Kruskal–Wallis test was performed to compare ΔE values among all groups. The post hoc tests was used after Kruskal–Wallis, with level of statistical significance set at P ≤ 0.05. Results: BN–Cr coating statistically significantly increased the hardness of all types of ceramics (P < 0.05). BN coating did not change the hardness statistically significantly (P > 0.05). The mean ΔE values indicated clinically noticeable (over the limit of 3.7) color change in all groups except for the EP-BN and T-BN groups. Conclusion: Although BN–Cr coating in this thickness had a negative effect on color, it increased the hardness of the ceramics and could be useful in the palatal region.

Background: This study investigated the influence of erbium-doped: yttrium aluminum garnet (Er:YAG) laser on the pull-out fracture load of fiber-reinforced composite (FRC) posts luted to dentin with different resin cements. Materials and Methods: In this in vitro experimental study, 90 premolars were endodontically treated. The post spaces were prepared, and the teeth were divided into three groups dependent on the cement applied for luting FRC posts: Group 1: An etch-and-rinse system, Group 2: A self-etch cement, and Group 3: A self-adhesive cement. After 6 months' storage and thermocycling, each group was divided into three subgroups (n = 10) according to the treatment applied for removing the posts; subgroup 1: Control, subgroup 2: Treatment with Er:YAG laser at 250 mJ, 20 Hz, and subgroup 3: Treatment by Er:YAG laser at 300 mJ, 10 Hz. The pull-out load was recorded in Newton. The data were analyzed by two-way ANOVA at P < 0.05. Results: The fracture load was significantly affected by the cementation group (P = 0.005) and treatment subgroup (P = 0.008). The pull-out load of self-etch cement was significantly greater than that of the self-adhesive and etch-and-rinse systems (P < 0.05). Treatment with Er:YAG laser caused a significant reduction in pull-out load of FRC posts (P < 0.05). Conclusion: The fracture load of fiber posts is influenced by the type of cement and treatment applied. Post removal would be less challenging when using a self-adhesive or conventional etch-and-rinse cement or using Er:YAG laser at the FRC-resin interface.

Background: Remineralization is currently considered a treatment option for many clinicians. The present study was conducted to compare the effect of three remineralizing agents on microhardness of initial caries lesions in primary teeth. Materials and Methods: In this in vitro study, 96 enamel samples were prepared. Microhardness was first measured for all the samples using the Vickers microhardness test. After developing the initial caries lesions, the microhardness of all the demineralized samples was measured, and the samples were then divided into four groups (n = 24). Casein phosphopeptide–amorphous calcium phosphate in Group 1, Remin Pro in Group 2, and acidulated phosphate fluoride gel in Group 3 were placed on the samples for 4 min. The control group received no treatments. The microhardness of the samples was measured again following a pH cycle of 5 days. The data were analyzed by ANOVA and the post hoc test at the significance level of P < 0.05. Results: The mean microhardness reduced significantly in all the groups following the development of initial caries lesions and after the pH cycle of 3 days (P < 0.001). After the remineralization and pH cycle of 5 days, the mean microhardness was significantly lower in the control group compared to the other three groups (P < 0.001) and had increased in the three treated groups. The microhardness recovery rate also increased in the treated groups compared to the control group, but no significant differences were observed between the three groups themselves (P > 0.05). Conclusion: Remin Pro can be used as an effective substance for preventing tooth caries in children.

Canalicular adenoma (CA) is a rare, benign salivary gland tumor that has special tendency to occur in the upper lip. Buccal mucosa is the second most common site. It occurs more often in older patients with peak prevalence in the seventh decade of life. A definitive female predominance has been reported. According to the latest English published literature, 531 cases of CA have been reported. We present a case of CA of the hard palate that presented in a 29-year-old female patient. The histopathological and immunohistochemical findings showed typical features of CA and intense expression of pan-cytokeratin and S-100 protein. We also review its differential diagnosis from other salivary gland tumors.

Background: The maximum conservation of tooth structure and the use of restorative materials with elastic modulus close to the dental structure may promote greater longevity of the tooth/restoration complex. This study was conducted to evaluate the effect of cavity design and material type on fracture resistance and failure pattern of molars restored by computer-aided design/computer-aided manufacturing (CAD/CAM) inlays/onlays. Materials and Methods: In this in vitro study, 55 human maxillary molars were embedded in resin blocks and divided into control group (CG) and five main groups: Group 1: Inlay, Group 2: Conventional onlay/mesiobuccal (MB), Group 3: Conservative onlay/MB, Group 4: Conventional onlay/MB and distobuccal (DB), and Group 5: Conservative onlay/MB and DB. Then, each group was divided into two subgroups: (A) CeraSmart (CS) and (B) Katana Zirconia (KZ). Restorations were cemented by RelyX Ultimate and then thermocycled. The universal testing machine was used to measure fracture loads. Failure was determined using a magnifying lens. Data were statistically analyzed using ANOVA followed by Tukey's post hoc test (P < 0.05). Results: Group 5 showed the highest significant fracture load, whereas the least significant value was recorded in Group 2. KZ recorded higher significant fracture loads than CS in all tested groups. Groups 1, 2, and 3 restored by CS showed lower fracture load than CG, but the difference was insignificant with Group 1. CS restorations showed restorable failure, while unrestorable pattern was predominant in KZ restorations (P < 0.05). Conclusion: KZ inlays and onlays can be used safely in terms of fracture resistance as both have values exceed the physiologic requirements. CS inlays and onlays/MB and DB are of fracture resistance comparable to intact teeth. The use of conservative onlay design with more cusp coverage guarantees better resistance of CS restorations. Being force absorbing material, the predominant failure of teeth restored by CS was restorable.

Background: The relative high caries risk of pits and fissures highlights the importance of protecting these areas. The aim is to determine the effect of sodium hypochlorite (NaOCl) on the shear bond strength (SBS) of resin-based pit and fissure sealant (RBPFS) material to enamel using resin-modified glass ionomer cement (RMGIC) and fluoride-releasing self-etch resin (FRSE) adhesives. Materials and Methods: In this in vitro study extracted third molar teeth without carious lesions or defects were divided into five experimental groups (n = 20). Group A: (Control group) etch (35% phosphoric acid) for 15 s and RBPFS applied. Group B: Etch for 15 s, FRSE and RBPFS applied. Group C: Pretreated with 5% NaOCl and similar steps to Group B. Group D: Etch for 15 s then RMGIC bonding agent and RBPFS applied. Group E: Pretreated with 5% NaOCl and then similar steps to Group D. SBS was determined using a universal testing machine. The tested specimens were examined under a field-emission scanning electron microscope. Data were analyzed using one-way ANOVA and post hoc Tukey's tests (P=0.05). Results: A statistically significant difference between the test groups was observed; Group C showed the highest SBS mean value (7.52 ± 2.74 MPa) and Group D showed the lowest (4.48 ± 1.81 MPa) (P < 0.001). Pretreatment with NaOCl increased the SBS of fissure sealant when Riva bond LC was used (P = 0.049). Conclusion: The use of NaOCl as pretreatment can increase the SBS of RBPFS to enamel using RMGIC adhesive. FRSE adhesive did not show improvement in SBS values using pretreatment.

Background: Various factors affect child behavior in different situations such as in a dental clinic. The purpose of this study was to investigate the relationship between temperament and child behavior during routine dental treatment. Materials and Methods: The present study is a descriptive-analytic study that included 199 children aged 3–7-years from patients referred to a dental clinic of Guilan University of Medical Sciences in 2017–2018. The Children's Behavior Questionnaire, which is specific to children aged 3–7 years, was used to assess children's dental temperament. Children's behaviors during dental treatment were recorded using Frankl scale. Finally, the data were analyzed by the SPSS-16 statistical software. Results: About 47.9% of the samples were female, with a mean temperament score of 4.79 which was significantly higher than males (P < 0.05). Almost 2.4% of children had completely negative behaviors and 2.8% had a completely positive behavior. The mean scores of fear (P = 0.008) and anger (P = 0.004) in children with completely negative behavior were higher than those with completely positive behavior. Moreover, the average scores of inhibitory control (P = 0.003) and perceptual sensitivity (P = 0.001) in completely positive children were higher than completely negative children. Conclusion: The results of the present study showed that girls had a better mean score of temperament than boys. The inhibitory control and perceptual sensitivity in completely positive children were significantly higher than negative children. In addition, a higher mean score of fear and anger was observed in completely negative children.

The current global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its associated coronavirus disease (COVID-19), has grasped the attention of entire international community and has caused widespread public health concerns. All the efforts taken globally to curtail the novel COVID-19; the outbreak is still on a rise owing to the community spread pattern of this infection. COVID-19 is a zoonotic infection that, like other coronavirus infections, is believed to have been originated in bats and pangolins, and later transmitted to humans. Once in the human body, this coronavirus (SARS-CoV-2) is abundantly present in nasopharyngeal and salivary secretions of affected patients and its spread is predominantly thought to be respiratory droplet in nature. Dental professionals may soon encounter patients with suspected or confirmed SARS-CoV-2 infection and will have to act carefully not only to provide care but at the same time prevent spread of infection. Thus, the aim of this article is to provide a brief overview of the epidemiology, symptoms and routes of spread of the novel COVID-19 infection. In addition to this, specific recommendations for dental practice are prescribed for patient screening, infection control strategies, and patient management protocol.