In vitro effect of beer, red and white wine on the morphology and surface roughness of human enamel.

BACKGROUND: Beer, red and white wine are acidic drinks whose frequent consumption can increase the risk of dental erosion. OBJECTIVES: To establish the effect of beer, red and white wine on the morphology and surface roughness (SR) of human enamel using different exposure times in a cyclic deand remineralization model in vitro. MATERIAL AND METHODS: The experiment included 33 surgically extracted impacted human third molars from patients aged 18-25 years. Enamel samples obtained by cutting crowns (n = 132) were submitted to alternate cycles of demineralization in (1) beer, (2) red wine, (3) white wine, (PC) positive control (orange juice), and remineralization in artificial saliva, which also represented a medium for negative control (NC). The experiment included cycles with different exposure times in alcoholic beverages and orange juice of 15, 30 and 60 min. Thus, 12 groups were formed (for each drink and each exposure time) containing 10 samples each, while the NC group consisted of 12 samples. Experiments were repeated 3x/day for 10 days. Enamel surface alterations were determined by stylus profilometry (average surface roughness (Ra)) and scanning electron microscopy (SEM). The Shapiro-Wilk test, independent samples Kruskal-Wallis test and multiple comparisons (all pairwise) were performed. RESULTS: With increasing exposure time, there was a positive correlation with Ra for white wineand orange juice-immersed samples (60 min compared to 15 min), which was also observed using SEM. There was no significant difference in the Ra between the other experimental samples for the same exposure time. CONCLUSIONS: This study confirms a certain erosive potential of beer, red and white wine, and a significant relationship with pH, titratable acidity (TA) and SR, but not with the exposure time for all tested alcoholic beverages. Moreover, differences among the ultrastructural patterns caused by alcoholic beverages over the enamel surface were observed.

Effects of Autoclave Sterilization on Cyclic Fatigue Resistance in 5 Types of Rotary Endodontic Instruments: An In Vitro Study.

BACKGROUND Rotary endodontic instruments are increasingly used in root canal treatment and have replaced stainless steel manual files. Cyclic fatigue is the cyclic loading of stress to produce deformation or fracture. This study aimed to evaluate and compare the effects of autoclave sterilization on cyclic fatigue in 5 types of rotary endodontic instruments. MATERIAL AND METHODS ProTaper Universal, BioRace, ProTaper Next, Twisted File, and HyFlex CM instruments were included in this study. Each type included 96 instruments, divided into 4 groups according to the number of sterilization cycles (0, 1, 3, 5). After sterilization, each group of instruments was divided into 2 subgroups and tested for cyclic fatigue in 2 simulated canals (45 degrees both and 2 radii, 2 mm and 5 mm). The number of cycles to failure (NCF) was calculated, and statistical analyses were carried out using the t test, Mann-Whitney U test, and ANOVA, followed by the Tukey post hoc test (p<0.05). Fracture surfaces were analyzed using scanning electron microscopy (SEM). RESULTS Within the group of non-sterilized instruments, ProTaper Universal showed significantly lower resistance to cyclic fatigue compared to the other types of instruments (p<0.001). After repeated sterilization, a significantly higher mean of NCF was observed for BioRace (p<0.001), ProTaper Next (p<0.001), Twisted File (p<0.001), and HyFlex CM (p<0.001) compared to ProTaper Universal. The resistance of HyFlex CM was significantly higher compared to the other types of instruments (p<0.001). CONCLUSIONS The findings from this study showed that autoclave sterilization of newer rotary endodontic instruments could increase resistance to cyclic fatigue.

Determining the Impact of the COVID-19 Pandemic on Dental Care in the Serbian Adult Population: An Online Questionnaire-Based Study.

BACKGROUND Emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus) could lead to an increase in dental anxiety, avoidance of dental visits, and general neglect of oral health. This online questionnaire-based study conducted in April and May of 2021 in Serbia aimed to determine the impact of the coronavirus disease 2019 (COVID-19) pandemic on dental care. MATERIAL AND METHODS The study included 2060 adult citizens of the Republic of Serbia who participated in an anonymous online questionnaire based on a 5-point Likert scale. Data were collected on dental care routine prior to and during the pandemic, and the fear of negative consequences for oral health. The results were statistically analyzed using descriptive statistics, Pearson's correlation coefficient, ANOVA, and the paired t test. RESULTS Approximately one-fifth of the respondents postponed dental visits during the pandemic. Concern about postponing dental treatment was expressed by more than one-half of the respondents (57.1%), while 21.4% thought that they were already experiencing the consequences. Avoidance of preventive examinations and improvement of oral hygiene are more common among the elderly compared to younger respondents (P=.000). CONCLUSIONS The COVID-19 pandemic did not significantly affect the habit of avoiding dental interventions due to fear, but it did lead to part of the population completely avoiding even urgent dental interventions during the peak of the pandemic, and opting for tooth extraction rather than treatment. The strongest impact on dental care in the pandemic was among people over 64 years old.

The Use of Acrylate Polymers in Dentistry.

The manuscript aimed to review the types of acrylate polymers used in dentistry, as well as their chemical, physical, mechanical, and biological properties. Regarding their consistency and purpose, dental acrylate polymers are divided into hard (brittle), which includes acrylates for the production of plate denture bases, obturator prostheses, epitheses and maxillofacial prostheses, their repairs and lining, and soft (flexible), which are used for lining denture bases in special indications. Concerning the composition and method of polymerization initiation, polymers for the production of denture bases are divided into four types: heat-, cold-, light-, and microwave-polymerized. CAD/CAM acrylate dentures are made from factory blocks of dental acrylates and show optimal mechanical and physical properties, undoubtedly better monomer polymerization and thus biocompatibility, and stability of the shape and colour of the base and dentures. Regardless of the number of advantages that these polymers have to offer, they also exhibit certain disadvantages. Technological development enables the enhancement of all acrylate properties to respond better to the demands of the profession. Special attention should be paid to improving the biological characteristics of acrylate polymers, due to reported adverse reactions of patients and dental staff to potentially toxic substances released during their preparation and use.