Surface roughness and microhardness evaluation of composite resin restorations subjected to three different polishing systems immediately and after 24 h: An in vitro study.

Background: Finishing and polishing of composite resin restorations can be considered two different procedures or two steps of a single procedure. During the finishing procedure, contours are corrected while margins and irregularities are smoothened. The polishing procedures result in the production of a smooth and lustrous finish. Consensus regarding the correct timing for initiating the steps of finishing and polishing after the curing of the composite resins is divided. Some authors support immediate finishing and polishing while other authors support delaying the finishing and polishing procedures. Aim: The aim of this study is to evaluate the surface roughness and microhardness of composite resin restoration subjected to finishing and three different polishing systems immediately and after 24 h. Materials and Method: Eighty composite resin samples were prepared. A Teflon mold was made which was customized for this study having dimensions of 10-mm diameter and 2-mm depth. For the first group of specimens, Group I (n = 20) the composite resin surface was covered with Mylar Strips which acted as control. The other specimens (n = 60) were prepared without the use of a Mylar strip, followed by curing. For all the samples, curing was done with a light-emitting diode for 40 s each. Eighty light-cured samples were divided equally into 4 groups, each group containing 20 samples (n = 20). Out of the 20 samples, in the second, third, and fourth groups, (Kenda C. G. I., Shofu Super-snap X-Treme, and Eve Diacomp Plus Twist) 10 samples were finished and polished immediately after curing and the other 10 samples were finished and polished after 24 h of curing. The samples in Groups II, III, and IV were subjected to finishing by a 12-fluted tungsten carbide bur and were polished according to the respective manufacturer's instructions. The samples were then subjected to quantitative analysis of surface roughness by a noncontact three-dimensional optical profilometer (Bruker GT-Q; Ettlingen, Germany) and qualitative analysis of surface roughness by a scanning electron microscope (Zeiss EVO 18 Special Edition; Carl-Zeiss-Strasse; Oberkochen Germany) at ×10,000 magnification. The samples were also subjected to Vickers microhardness measurement using a microhardness tester (Leica VMHT 001; Walter UHL GmbH, Germany) under 100 g load over 10 s. Conclusion: A. For surface roughness: The samples cured under Mylar strips gave the least surface roughness values (0.25 ± 0.032). Immediate finishing and polishing procedures led to statistically less surface roughness than when finishing and polishing procedures were performed after a delay of 24 h for all polishing systems used B. For microhardness: The samples cured under Mylar strips gave the least microhardness values (57.1 ± 2.03). Delayed finishing and polishing increased microhardness values in all finishing and polishing systems used. Different polishing systems did not have any significant effect on the microhardness values in immediate and delayed finishing and polishing groups.

Comparative evaluation of adhesion of glass fiber post to the root dentin after surface treatment of post and using universal bonding agent: An in vitro study.

Objective: The purpose of the study is the evaluation and comparison of surface roughness and bond strength of glass fiber post (GFP) after different types of surface treatment and the application of a universal bonding agent. Materials and Methods: Forty GFPs were divided into four groups based on surface treatment: Group I, silane coupling agent application for 60 s; Group II, air abrasion with 30 µm silicon dioxide powder particles in 2.5 bar pressure from 2 cm distance for 10 s, followed by silane coupling agent application; Group III, 9% hydrofluoric acid application for 10 s, rinsed and air-dried, followed by silane coupling agent application; and Group IV, silane coupling agent application, followed by universal bonding agent application. Surface roughness evaluation is done by a profilometer. All posts were cemented in the root of the maxillary central incisor with resin cement. After that, root was placed in an acrylic mold, and the external end part of the post was mounted on another acrylic mold. Pull-out bond strength was measured by a universal testing machine. Results: Highest surface roughness and bond strength values were found in Group II. Conclusion: Pretreatment of GFP increases the surface roughness of post as well as bond strength of post to root dentin. There is a correlation between surface roughness and bond strength. However, the use of only universal bonding agent also showed comparable pull-out bond strength of GFP, which means only use of universal bonding agent also a new alternative as pretreatment of GFP and helps in increase in bond strength.

Evaluation of debris and smear layer formation using three different NI-TI rotary instrument systems: An in vitro scanning electron microscope study.

Aim: The aim of the study is to evaluate of debris and smear layer formation after using rotary ProTaper Universal, Twisted File, and XP Endo file systems under scanning electron microscope. Materials and Methods: Forty freshly extracted mandibular second premolar teeth were taken to decoronate at the cementoenamel junction to make the remaining root length 15 mm. Specimens were divided into four groups of 10 teeth each, Group I (control) - no instrumentation. Group II - ProTaper Universal rotary file (F2), Group III - twisted file (ISO size 0.25 and 6% taper), Group IV - XP Endo file (ISO size 0.25). During instrumentation, 5 ml normal saline was used as irrigating agent. Grooves parallel to the longitudinal axis of the root were made on the mesial and distal surface of each specimen to split it into two halves and examined under scanning electron microscope at ×1500 and ×5000 magnification. Photomicrographs were taken to evaluate debris and smear layer. Evaluation of photomicrographs was done using a score index. Results: One-way analysis of variance (ANOVA) was used to compare more than one means at a time. Tukey's critical difference followed by ANOVA was used to compare the mean values pair wise. P <0.05 was considered to be statistically significant. Among all the file systems, Group II showed maximum amount of debris (3.50 ± 1.109) followed by Group III (2.83 ± 1.238) and least amount was showed by Group IV (2.65 ± 1.122) at all levels (cervical, middle, and apical third). Among all the experimental groups, Group II showed maximum amount of smear layer (2.75 ± 1.149) followed by Group III (2.40 ± 0.982) and least amount of smear layer shown by Group IV (2.10 ± 0.841) at all levels (cervical, middle and apical third), the result was statistically significant (P < 0.05). Conclusions: At all the levels (cervical third, middle third, and apical third), among all the experimental groups, highest amount of debris and smear layer was formed by ProTaper Universal rotary file followed by Twisted file and least amount showed by XP Endo file system. In all the levels, control group showed highest amount of debris but least amount of smear layer.

Microscopic evaluation of sealer penetration and interfacial adaptation of three different endodontic sealers: An in vitro study.

Background: The dentinal tubular penetration depth and interfacial adaptation of sealer are important factors for successful root canal treatment. Aims: This study aims to assess and evaluate the sealer penetration depth and interfacial adaptation of AH Plus, Apexit Plus, and GuttaFlow Bioseal sealer to root dentin. Materials and Methods: After decoronating sixty extracted single-rooted premolar teeth, preparation was done using ProTaper Gold rotary files until F3. The samples were randomly divided into three groups (n = 20 each) consistent with the sort of sealer used for obturation. After obturation with lateral compaction technique, half of the samples (n = 10 each) were sectioned transversely for measuring tubular depth penetration under a confocal laser scanning microscope. Longitudinal sections were obtained for the rest half the samples to gauge the difference of sealer using the scanning electron microscope. Statistical Analysis Used: Data were analyzed using one-way analysis of variance and Tukey's post hoc tests. Results: GuttaFlow Bioseal has shown a significantly higher depth of sealer penetration and minimum interfacial adaptation than resin-based sealer and calcium hydroxide-based sealer (P < 0.05). Conclusion: At all root regions, the GuttaFlow Bioseal sealer exhibited more sealer penetration and minimum interfacial adaptation whereas the Apexit Plus sealer exhibited less sealer penetration and maximum interfacial adaptation.

Comparative evaluation of different probiotic products on salivary Streptococcus mutans and Lactobacillus level in caries risk population.

INTRODUCTION: Dental caries is a multifactorial disease with the main causative organism being Streptococcus mutans and Lactobacillus spp. "Probiotics" are defined as living microorganisms, principally bacteria, which are safe for human consumption and when ingested in sufficient quantities, have beneficial effects on human health, beyond basic nutrition. These can be used to replace the pathogenic strains of bacteria with the nonpathogenic type in the oral cavity thus can help prevent dental caries. AIMS: To evaluate and compare the role of probiotic milk and lozenges on S. mutans and Lactobacillus spp. count on patients who are exposed to probiotics continuously for 7 days. MATERIALS AND METHODS: Sixty volunteers who were prone to caries were divided into three equal groups. Experimental groups were given probiotics daily for 7 days. In Group A, patients were given milk without any probiotics (control); in Group B, probiotic milk is given; and in Group C, probiotic lozenges are given. Saliva samples were assessed on the 1st day and after 7 days of intervention. The collected saliva samples were inoculated on the selected culture media and estimation was done by measuring the colony-forming unit. STATISTICAL ANALYSIS USED: Statistical analysis was performed using Student's paired t-test and multiple comparisons by Tukey's honest significant difference test. RESULTS: There was a significant reduction in salivary S. mutans level in both experimental groups after 7 days (P < 0.05). However, there was no significant difference in Lactobacillus count before and after the intervention. CONCLUSIONS: Probiotics have a role in reducing salivary S. mutans count. Probiotics lozenges showed greater efficacy in reducing salivary S. mutans count than probiotic milk.

Comparative evaluation of surface roughness and color stability of nanohybrid composite resin after periodic exposure to tea, coffee, and Coca-cola - An in vitro profilometric and image analysis study.

AIM: The aim of this study is to evaluate the surface roughness and color stability of a nanohybrid composite resin after exposure to tea, coffee, Coca-cola, and artificial saliva on the 7th, 14th, and 28th day. MATERIALS AND METHODS: Forty specimens of nanohybrid composite resin discs of dimension 6 mm × 2 mm were fabricated and were randomly divided into four equal groups based on beverages (Group 1: control group - artificial saliva, Group 2: Tea, Group 3: Coffee, and Group 4 : Coca-cola). Baseline readings of surface roughness (Ra) and color change (ΔE) were obtained by profilometer and digital image analysis technique in CIE l*a*b scale followed by the readings (ΔE) taken on the 7th, 14th, and 28th day of exposure to respective beverages. STATISTICAL ANALYSES: One-way analysis of variance (ANOVA) followed by post hoc Tukey's test and paired t-test along with Pearson's correlation with a P = 0.05. RESULTS: Overall, highest surface roughness was obtained in the samples exposed to Coca-cola followed by coffee and tea while the least surface roughness was obtained in the samples exposed to artificial saliva (control group) which was statistically significant (P < 0.05). Overall highest color change was obtained in tea followed by coffee and Coca-cola. The least color change was observed in the samples exposed to artificial saliva (control group) (P < 0.05). CONCLUSION: Surface roughness and color change were time dependent as both increased with time. Furthermore, greater the surface roughness, more was the color change observed in all the groups at all tested time intervals.

Position Statement of IACDE for managing dental patients during COVID-19.

Coronavirus disease 2019 (COVID-19) has been a major health concern globally ever since it was declared as Pandemic by the World Health Organization in March 2020. Due to the evolving and contagious nature of coronavirus, it continues to remain a threat for dental health-care personnel. As the virus travels from person-to-person via direct contact through droplet inhalation, cough, and sneeze or through contact transmission, it remains infectious even through inanimate surfaces. A seemingly healthy asymptomatic person may have the potential to trigger the spread of this disease. Coronavirus has the capability of spreading through community transmission. There is no specific treatment or vaccine as of now for stopping the spread of COVID-19, hence universal precautions and awareness with mass involvement is required to ward off this pandemic. Dental health-care personnel are at immense risk due to the near proximity with patients and continual exposure to saliva, blood, and other body fluids. Management protocol regarding awareness and preventive measures should be laid down for dental clinic/hospital to contain the outspread of this infectious disease.

Comparative evaluation of microleakage of three different direct restorative materials (silver amalgam, glass ionomer cement, cention N), in Class II restorations using stereomicroscope: An in vitro study.

AIM: The aim of the study is to compare the microleakage of three different direct restorative materials (amalgam [AA], glass ionomer cements [GICs], and Cention N [CN]) in Class II restorations using stereomicroscope. MATERIALS AND METHODS: A standardized Class II cavity preparation was made involving the proximal and occlusal surfaces. All prepared samples were randomly divided into 3 experimental groups, with 10 teeth each according to the restoration material used: Group I-AA; Group II-GICs; and Group III-CN. The restored teeth were stored for 24 h in distilled water and thermocycled for 500 cycles between 5°C and 55°C with a dwell time of 30 s in each bath. Samples were immersed in 0.5% basic fuchsin dye for 24 h. The teeth were sectioned along the mesiodistal direction. The dye penetration of the occlusal and gingival margins of each section was evaluated independently by the observer using a stereomicroscope. RESULTS: Statistical analysis revealed lower microleakage scores in GIC and CN. Higher microleakage was observed in Group AA. Mean microleakage score of Group-I (AA) was the highest of all groups. Mean microleakage score of Group-III (CN) was the lowest of all groups. As per the critical differences (CD), the mean microleakage score of Group-III CN) was significantly lower than that of Group-I (AA), Group-II (GIC) (P < 0.01). There is no significant difference between the mean microleakage score of Group-I (AA) and Group-II (GIC). CONCLUSION: Out of all the restorative materials, CN a newer restorative material displayed minimum microleakage compared to AA and GICs.

Effect of four different dentifrices applied by customized automated brushing device on enamel surface abrasion: An in vitro profilometric study.

AIM: The aim of this study is to evaluate the enamel surface abrasion using four different dentifrices and a customized automated brushing machine under a profilometer. MATERIALS AND METHODS: A total of 30 enamel blocks (9 mm × 9 mm × 2 mm) were prepared from freshly extracted maxillary central incisors which were randomly divided into five equal groups (Group 1: specimens brushed with Colgate Total, Group 2: specimens brushed with Colgate Lemon and Salt, Group 3: specimens brushed with Colgate Visible White, Group 4: specimens brushed with Colgate Sensitive, and Group 5: intact enamel surface). Samples were brushed using a customized automated toothbrushing machine for 60 min. A profilometric read out (Ra value) was taken for each group subjected to brushing and also for the control group. STATISTICAL ANALYSIS: Statistical analysis used in this study was one-way analysis of variance followed by post hoc Tukey's test. RESULTS: Statistically significant differences (P < 0.05) were observed in the values of enamel abrasion (Ra) among Group 1-Group 4 whereas Group 5 (control group) had no significant difference in enamel abrasion (P > 0.05). CONCLUSION: The highest enamel abrasion was observed in the group with Colgate Visible White toothpaste, and the least enamel abrasion was seen in the group with Colgate Sensitive Plus.