Fear of COVID-19 associated with burnout syndrome in dentists of the Health Directorate of the National Police of Peru: a cross-sectional study at national level under multivariable regression model.

BACKGROUND: During the pandemic, many police dentists had the crucial responsibility of ensuring law and order while providing dental care by taking government-approved health measures to stop the spread of the coronavirus. The aim of this study was to assess the association between the fear of COVID-19 and Burnout syndrome in Peruvian dentists belonging to the Health Department of the National Police of Peru (PNP), taking into account possible confounding variables. METHODS: This cross-sectional and analytical study included 182 PNP dentists. The Fear COVID-19 Scale assessed fear of COVID-19 and the Maslach Burnout Inventory Test assessed burnout syndrome. The association between the fear of COVID-19 and Burnout syndrome (self-fulfilment) was analyzed using Spearman's Rho. A multivariable Poisson regression model with a robust variance estimation method was employed to evaluate the impact of fear of COVID-19 on the various dimensions of Burnout syndrome, considering possible confounding variables. The statistical significance level was set at p < 0.05. RESULTS: Under bivariate analysis, fear of COVID-19 was significantly linked with low direct intensity toward emotional exhaustion (Rho = 0.325, p < 0.001), very low direct intensity toward depersonalization (Rho = 0.180, p = 0.015), and very low inverse intensity toward self-fulfilment (Rho =-0.186, p = 0.012). Under multivariable analysis, it was observed that dentists who exhibited fear of COVID-19 were 3.4 and 3.7 times more likely to experience emotional exhaustion and depersonalization, respectively (APR = 3.40, 95% CI: 1.74-6.63 and APR = 3.68, 95% CI: 1.31-10.37), as compared to those who did not display fear of COVID-19. Moreover, none of the potential confounding factors were found to have a significant impact on emotional exhaustion (p > 0.05), depersonalization (p > 0.05), and self-fulfilment (p > 0.05). CONCLUSION: Fear of COVID-19 was significantly associated with emotional exhaustion and depersonalization, and inversely associated with self-fulfilment. PNP dentists who exhibited fear of COVID-19 were at greater risk for emotional exhaustion and depersonalization. In developing Burnout syndrome, no significant impact was observed from factors such as age, gender, marital status, children, hierarchy, years of service, work area, private practice, work over 40 h per week, type of service, work performed, sport practice and daily exercise time.

Factors associated with knowledge about pharmacological management of pregnant women in Peruvian dental students: a logistic regression analysis.

BACKGROUND: Clinical management to maintain or restore oral health through the use of drugs during pregnancy is crucial, since at this stage physiological changes significantly influence the absorption, distribution and elimination of the drug, considering also that excessive administration of drugs during this period may have adverse effects on the mother and/or fetus. Therefore, the aim of the present study was to evaluate the factors associated with knowledge of pharmacological management of pregnant women in dental students of a Peruvian university located in the capital and province. METHODS: This analytical, cross-sectional, prospective and observational study assessed 312 Peruvian dental students from third to fifth year of study between February and April 2022. A validated questionnaire of 10 closed questions was used to measure knowledge about pharmacological management in pregnant women. A logit model was used to assess the influence of the variables: gender, age, year of study, marital status, place of origin and area of residence. A significance of p < 0.05 was considered. RESULTS: The 25.96, 55.13 and 18.91% of the dental students showed poor, fair and good knowledge about pharmacological management in pregnant women; respectively. In addition, it was observed that students under 24 years of age and those from the capital were significantly (p < 0.05) 44% less likely to have poor knowledge of pharmacological management in pregnant women compared to those aged 24 years or older (OR = 0.56; CI: 0.34-0.92) and those from the province (OR = 0.56; CI: 0.32-0.98); respectively. Finally, those in their third and fourth year of study were significantly three times more likely to have poor knowledge (OR = 3.17; CI: 1.68-5.97 and OR = 3.88; CI: 2.07-7.31; respectively) compared to fifth year dental students. CONCLUSION: The knowledge of dental students about pharmacological management in pregnant women was predominantly of fair level. In addition, it was observed that being under 24 years of age and being from the capital city were protective factors against poor knowledge, while being a third- and fourth-year student was a risk factor. Finally, gender, marital status and area of residence were not influential factors in the level of knowledge.

Factors associated with the perception of university professors about academic dishonesty in dental students from two peruvian universities: analysis under multivariable regression model.

BACKGROUND: Academic dishonesty is an intentional behavior that transgresses ethics in the teaching-learning process. The present study aimed to evaluate the factors associated with the perception of university professors about academic dishonesty in dental students from two universities in the Peruvian capital. METHODS: This cross-sectional, analytical study evaluated 181 professors from two Peruvian universities between March and July 2022. A validated 28-item questionnaire was used to measure the perceived academic dishonesty of their students. A logit model was used to evaluate the influence of the variables gender, marital status, place of origin, academic degree, specialization, academic area, years of teaching experience, scientific publications, ethical training and university of origin, considering a significance level of p < 0.05. RESULTS: According to the median, professors perceived that their students sometimes had attitudes and motivations to commit academic dishonesty. The professors whose origin was the capital city were twice as likely to perceive dishonest attitudes in dental students as those whose origin was a province (OR = 2.04; 95% CI: 1.06-3.93). University professors in pre-clinical courses were 0.37 times less likely to perceive dishonest attitudes than those teaching in the dental clinic (OR = 0.37; CI: 0.15-0.91). University professors in basic science courses and professors in preclinical courses were 0.43 times (OR = 0.43; CI: 0.19-0.96) and 0.39 times (OR = 0.39; CI: 0.15-0.98) less likely to perceive dishonest motivations in their students compared to university professors in the dental clinic. Gender, marital status, academic degree, specialty, years of teaching experience, scientific publications and ethical training were not found to be influential factors (p > 0.05). CONCLUSION: Although all university professors surveyed perceived dishonest attitudes and motivations in their students, university professors from the capital city perceived such attitudes more. In addition, being a preclinical university professor was a hindered factor for perceiving such dishonest attitudes and motivations. It is advisable to implement and constantly disseminate regulations that empower academic integrity as well as to manage a system for reporting misconduct and to make students aware of the impact of dishonesty in their professional training.

Sociodemographic factors associated with knowledge and attitudes of Peruvian dental interns about dental shade selection.

BACKGROUND: The dentist should have a thorough knowledge of the science, protocols and procedures for dental shade selection in order to mimic dental tissue with restorative materials, respecting the individual needs and attitudes of each patient and providing them with a pleasant and esthetically acceptable appearance. The present study evaluated the knowledge and attitudes of dental interns from two Peruvian universities about dental shade selection and its relationship with sociodemographic factors. METHODS: The present cross-sectional and analytical study was carried out on Peruvian dental interns from the Universidad Nacional Federico Villarreal and the Universidad Privada de San Juan Bautista during May to June 2022. Two validated questionnaires on knowledge and attitudes about dental shade selection were used. A Poisson regression model with robust variance using the adjusted prevalence ratio (APR) was used to assess the influence of the variables: age group, sex, place of origin and type of university, considering a significance level of p<0.05. RESULTS: The results showed that 40.8% (95% CI: 34.0% - 47.6%) of the interns presented unfavorable attitudes while 90.1% (95% CI: 86.0% - 94.2%) presented insufficient knowledge. It was also found that dental interns under 29 years of age were 32% less likely to have unfavorable attitudes (APR = 0.68, 95% CI 0.48 - 0.96) and 11% more likely to have insufficient knowledge (APR = 1.11, 95% CI 1.01 - 1.24) about tooth shade selection compared to dental interns aged 29 years and older. Finally, women were 55% more likely to have unfavorable attitudes about tooth shade selection compared to men (APR = 1.55; 95% CI: 1.08 - 2.22). CONCLUSION: The majority of dental interns presented insufficient knowledge and less than half had unfavorable attitudes about dental shade selection. In addition, being a student under 29 years of age was a risk factor for presenting insufficient knowledge and at the same time constituted a protective factor for presenting unfavorable attitudes. Likewise, being a female student was a risk factor for presenting unfavorable attitudes about dental shade selection.

Sociodemographic factors associated with the level of knowledge about management of epileptic patients in Peruvian dental students: a cross-sectional study under a multivariable analysis.

BACKGROUND: Epilepsy is a chronic neurological disease that could indirectly affect oral health, and it is necessary for dentists to be familiar with the specific needs of patients with epilepsy. Therefore, aim of the present study was to assess the factors associated with the level of knowledge about management of epileptic patients in Peruvian dental students. METHODS: This analytical, observational, cross-sectional and prospective study assessed 312 dental students from a Peruvian university during February to April 2022. A validated questionnaire of 20 closed multiple-choice questions was used to measure the level of knowledge about dental management in epileptic patients. A logit model was used to assess the influence of variables: gender, age, year of study, marital status, place of origin and area of residence, with the level of knowledge in dental students considering a significance level of p < 0.05. RESULTS: Of the total, 28.8%, 36.2% and 34.9% had a poor, fair and good level of knowledge, respectively, about the dental treatment of epileptic patients. On the other hand, it was observed that being a woman (OR = 0.44, CI 0.26-0.75) and being a third year student (OR = 0.39, CI 0.21-0.74) and fourth year student (OR = 0.43, CI 0.23-0.89) constituted a protective factor against poor knowledge about the dental management of epileptic patients, while being from the capital city constituted a risk factor. Finally, age, marital status and the students' area of residence were not considered influential factors (p > 0.05). CONCLUSION: Most of the students showed a poor and fair level of knowledge about the dental management of epileptic patients, with gender, academic year and place of origin being influential factors. It is advisable that authorities and teachers in the dental profession organize recurrent training programs on the care of patients with chronic diseases requiring special attention, since knowing general concepts, pharmacological management and dental care of epileptic patients will allow future dentists to develop competencies to improve and implement good quality care protocols for this group of patients.

Psychometric evidence of a perception scale about covid-19 vaccination process in Peruvian dentists: a preliminary validation.

BACKGROUND: In the current pandemic context, dental professionals have greater occupational risks due to their healthcare activity, placing their expectations on the vaccine as a means of protection and at the same time hoping that the immunization process will be safe, reliable and comfortable, giving them greater peace of mind when they return to work. Therefore, the aim of the present study was to develop and provide a preliminary validation of a scale to measure perception of the COVID-19 vaccination process in Peruvian dental professionals. METHODS: Cross-sectional study with instrumental design. The scale was self-administered virtually. It was distributed through social networks to 220 dental professionals from two universities in the Peruvian capital between June and August 2021. The Aiken V was used for content analysis, while descriptive statistics such as mean, variance, kurtosis and skewness were used for construct validation, in addition to Pearson's correlation matrix for analysis of the 18 items. Subsequently, a Parallel Analysis based on minimum rank factor analysis was performed. Finally, the reliability of the total scale and its dimensions was evaluated with Cronbach's alpha. RESULTS: The Aiken V coefficient values were favorable for all items. Parallel analysis indicated the existence of three dimensions. Principal component analysis with rotation suggested grouping eight items for the first dimension, six items for the second dimension and four items for the third dimension. These dimensions showed good reliability, as Cronbach's alpha was 0.87, (95% confidence interval [CI]: 0.84-0.90), 0.80 (95% CI: 0.75-0.84) and 0.82 (95% CI: 0.78-0.86), respectively. In addition, the overall reliability of the scale was 0.89 (95% CI: 0.86-0.91), being acceptable. CONCLUSIONS: The perception scale of the COVID-19 vaccination process in dental professionals proved preliminarily to be a valid and reliable scale that can be used for research purposes. However, it is recommended to extend its application and evaluate its metric properties in other health professionals.

Surface roughness and oxygen inhibited layer control in bulk-fill and conventional nanohybrid resin composites with and without polishing: in vitro study.

BACKGROUND: It has been demonstrated that dental restorations with rough surfaces can have several disadvantages such as pigment retention or plaque accumulation, which can facilitate caries formation, color variation, loss of brightness, degradation of restoration, among others. The present study aimed to assess surface roughness in bulk fill and conventional nanohybrid resins with and without polishing, controlling the oxygen inhibited layer. METHODS: This in vitro and longitudinal experimental study consisted of 120 resin blocks of 6 mm diameter and 4 mm depth, divided into two groups: Bulk Fill (Tetric® N-Ceram Bulk-fill, Opus Bulk Fill APS, Filtek™ Bulk Fill) and conventional nanohybrid (Tetric® N-Ceram, Opallis EA2, Filtek™ Z250 XT). Each resin group was divided into two equal parts, placing glycerin only on one of them, in order to control the oxygen inhibited layer. Subsequently, the surface roughness was measured before and after the polishing procedure with Sof-Lex discs. The data were analyzed with the T-test for related measures, and for comparison between groups before and after polishing, the non-parametric Kruskal Wallis test with the Bonferroni post hoc was used, considering a significance level of p < 0.05. RESULTS: Before polishing, the resin composites with the lowest surface roughness were Opus Bulk Fill APS (0.383 ± 0.186 µm) and Opallis EA2 (0.430 ± 0. 177 µm) with and without oxygen inhibited layer control, respectively; while after polishing, those with the lowest surface roughness were Opus Bulk Fill APS (0.213 ± 0.214 µm) and Tetric N-Ceram (0.097 ± 0.099 µm), with and without oxygen inhibited layer control, respectively. Furthermore, before and after polishing, all resins significantly decreased their surface roughness (p < 0.05) except Opus Bulk Fill APS resin with oxygen inhibited layer control (p = 0.125). However, when comparing this decrease among all groups, no significant differences were observed (p < 0.05). CONCLUSION: The Opus Bulk Fill APS resin with oxygen inhibited layer control presented lower surface roughness both before and after polishing, being these values similar at both times. However, after polishing the other bulk fill and conventional nanohybrid resins with and without oxygen inhibited layer control, the surface roughness decreased significantly in all groups, being this decrease similar in all of them.

Level of knowledge about metalloproteinases in dental students close to graduate from three universities in Peruvian capital city.

BACKGROUND: Metalloproteinases are proteolytic enzymes that degrade dentin and periodontal collagen; therefore, it is of special interest that dental students know its mechanism of action and how its effects can be inhibited. Therefore, the aim of this research was to evaluate the level of knowledge about metalloproteinases in dental students close to graduate from three universities in Peruvian capital city. MATERIALS AND METHODS: In this analytical, observational, cross-sectional and prospective study, 223 dental students close to graduate in three Peruvian universities were evaluated from September to November 2020. A questionnaire of 20 closed questions with three answers was validated and used to measure the level of general and dental knowledge about metalloproteinases. A logit model was used to evaluate the influence of the following variables: "gender" (X1), "type of university" (X2), "marital status" (X3) and "age group" (X4), in the knowledge levels of the students, considering a p-value <.05. RESULTS: Of the 223 dentistry students, it was obtained that the level of knowledge about metalloproteinases was predominantly low with 82.1%, (95% confidence interval (CI): 77.1%-87.1%) of the total. According to multivariate logistic regression analysis, "type of university" was the only variable that proved to have a significant influence (p = .022) on the level of knowledge about metalloproteinases with an odds ratio of (OR = 0.44; CI: 0.21-0.89), whilst the other variables "age group" (p > .05), "gender" (p = .058) and "marital status" (p = .114) were not considered influential factors. CONCLUSION: The majority of final year dental students in three Peruvian universities presented a low level of overall knowledge about metalloproteinases. In addition, private university students were 56% less likely to pass the subject knowledge test. On contrary, gender, age group and marital status did not significantly influence the level of knowledge of the students.

Microleakage in class II restorations of two bulk fill resin composites and a conventional nanohybrid resin composite: an in vitro study at 10,000 thermocycles.

BACKGROUND: The contraction presented by resin composites causes an increase in stress at the tooth-resin interface, causing micro-gaps that allow microleakage. This study aims to evaluate the degree of in vitro marginal microleakage in class II restorations with two bulk fill resin composites compared to a conventional nanohybrid resin composite. METHODS: The present study was an in vitro experimental design. A total of 30 standardized class II cavities were prepared in 15 human molars (mesially and distally). These cavities were later distributed in 3 groups according to the type of resin. Groups A and B were restored with bulk fill resin composites (Filtek-3 M/ESPE and Tetric N-Ceram-Ivoclar/Vivadent respectively) in a single increment of 4 mm. Group C was restored with the Filtek Z350 XT - 3 M/ESPE resin composite and two increments of 2 mm. Later, the restorations were subjected to 10,000 thermocycles between 5 °C to 55 °C and immersed in a silver nitrate solution (1 M for 24 h). The crowns were then sectioned mesiodistally and observed under the stereomicroscope to determine the degree of marginal microleakage at the occlusal and cervical areas. The results were analyzed with the Kruskal-Wallis and the Mann-Whitney U statistical tests. RESULTS: There were no statistically significant differences regarding the degree of microleakage between the three types of resin composites in the occlusal and cervical areas (p > 0.05). Similarly, there were no significant differences after comparing each resin type in its occlusal and cervical area (p > 0.05). CONCLUSION: Filtek Bulk Fill and Tetric N-Ceram Bulk Fill resin composites showed no statistically significant differences with the conventional nanohybrid resin composite Filtek Z350XT at both occlusal and cervical areas.

Shear bond strength of three different metal bracket base designs on human premolars: An in vitro comparative study.

Background: Adequate bracket-enamel bonding is critical to prevent detachment during orthodontic treatment and minimize any potential delay in results. The aim was to compare the shear bond strength of three metal bracket base designs: laser-structured base, mesh base, and retention grooves base. Material and Methods: In this experimental in vitro study, 54 human premolars were immersed for one week in 0.1% thymol solution, then placed in distilled water with weekly replacement until the start of the study. The premolars were cemented with brackets of varying base designs: A. Discovery® Smart (laser structured), B. Mini Master® Series (base with mesh), and C. Roth Max (base with retention grooves). All brackets were cemented using TransbondTM XT. A universal testing machine was used to evaluate the shear bond strength at a crosshead speed of 0.75 mm/min. Welch's one-factor ANOVA with robust variance and Tukey's post hoc test were used to compare means, with a significance level of p<0.05. Results: The average shear bond strength values were for the bracket with laser-structured base (14.78 ± 5.79 MPa), the bracket with mesh base (9.64 MPa ± 2.54 MPa) and the bracket with retention groove base (15.38 MPa ± 2.67 MPa). It was found that brackets with mesh bases had significantly lower shear bond strength than brackets with laser-structured bases (p=0.001) and brackets with retention grooves bases (p<0.001). No significant differences were observed between the latter two types of brackets (p = 0.893). Conclusions: The bracket base design influenced in vitro shear bond strength with significantly higher values observed for Roth Max and Discovery® Smart brackets compared to Mini Master® Series brackets. Key words:Shear strength, laser-structured bracket, bracket with mesh base, bracket with retention groove base.

Jawbone quality classification in dental implant planning and placement studies. A scoping review.

Aim: Cone beam computed tomography has become an attractive method for implant planning. However, in most cases, not all the information is taken advantage of and often the radiographic evaluation of bone quality is based on subjective assessment by the individual clinician. Therefore, the aim of this study was to examine classifications of bone tissue characteristics and methods for assessing them in dental implant planning and placement studies. Materials and Methods: Three databases (Pubmed, Scopus, Web of Science) were searched using specific index terms: "Bone quality, bone quantity, bone density, cone-beam CT and cone-beam computed tomography". Three reviewers selected titles and analyzed abstracts according to inclusion and exclusion criteria. Some descriptions of bone tissue characteristics (bone quality, density, and quantity) used before or during dental implant placement were selected and categorized. Results: The search yielded 442 titles. A total of 32 articles were selected and read in full text. Seventeen articles were considered relevant. Different classification systems were found to evaluate bone tissue characteristics as well as different examination protocols. Thirteen publications included in this review reported on bone quality and quantity using the Lekholm and Zarb classification. However, only four studies implemented and/or proposed modifications of the Lekholm and Zarb system. Four other publications described bone quality according to different classification systems such as Misch, University of California Los Angeles (UCLA), or Trisi and Rao. The assessment methods were often briefly described (or not described at all in one publication). Of the articles analyzed, five presented observer performance, whereas three presented diagnostic accuracy of the assessment method. Conclusion: Currently, there are different classification systems applied to dental implant planning and placement, particularly regarding whether bone quality or quantity affects treatment outcomes. However, most authors have not validated the diagnostic accuracy and reproducibility of the classification used. Therefore, it is necessary to develop a classification system consistent with characteristics of bone tissue, taking into consideration an adequate description of bone tissue assessment methods, their diagnostic accuracy, and observer performance.

Microtensile Bond Strength and Failure Mode of Different Universal Adhesives on Human Dentin.

AIM: The aim of this study was to compare the microtensile bond strength (µTBS) and failure mode of 4 different universal adhesive systems (UAs) on human dentin. MATERIALS AND METHODS: The study sectioned the occlusal thirds of 32 human third molars and divided them into 4 groups based on the adhesive system used. Group A: Palfique Universal Bond, Group B: Single Bond Universal, Group C: All-Bond Universal, and Group D: One Coat 7 Universal. The specimens underwent a 10,000-cycle thermocycling ageing process prior to testing (n = 32). Afterwards, 8 beams were obtained per group and subjected to µTBS testing using a digital universal testing machine at a speed of 1 mm/min. The microtensile bond strength values were analysed in Megapascals (MPa), and the failure mode was evaluated using a stereomicroscope. Welch's parametric ANOVA with robust variance and the Games-Howell post hoc test were used for µTBS comparisons, and Fisher's exact test was used to determine the association between adhesive type and failure mode. The significance level was set at P < .05. RESULTS: Group D showed a significantly higher µTBS than groups A (P < .001) and B (P < .001), but no significant difference was observed with group C (P= .075). Furthermore, groups B and C showed significantly higher µTBS than group A (P< .001 and P < .001, respectively), but there was no significant difference between groups B and C (P = .132). Additionally, group A exhibited a significant association with an adhesive failure mode (P < .05), whereas groups B, C, and D were significantly associated with a mixed failure mode (P < .05). CONCLUSION: The One Coat 7 Universal adhesive system showed higher microtensile bond strength values and higher chemical interaction with dentin compared to Palfique Universal Bond and Single Bond Universal. However, no significant differences were observed compared to All-Bond Universal.

Factors associated with dental interns and professors perception of the management of disabled patients: A cross-sectional study under multivariable analysis.

Background: Patients with disabilities experience oral health inequalities, including increased disease prevalence and unmet healthcare needs. The aim of this study was to assess factors associated to the perceived management of patients with physical disabilities among dental interns and professors at a university located in the capital city and a branch in a province in Peru. Methods: This cross-sectional, observational, and analytical study included 100 dental interns and 75 Peruvian dental professors and was conducted from January to April 2022. A validated perception scale was used to evaluate the management of disabled patients. For the statistical analysis, the study employed Pearson's chi-square test and Fisher's exact test, along with a Poisson regression model that used robust variance. The adjusted prevalence ratio (APR) was utilized to evaluate perception while taking into account factors such as gender, age, marital status, origin, professional experience, previous treatment of a patient with physical disability, and previous cohabitation with a disabled patient. The significance level was set at p < 0.05. Results: The 86 % of dental interns and 88 % of dental professors had a poor perception of managing disabled patients, with no significant association between them (p = 0.698). Male and female dental interns displayed significant differences in perception (p = 0.004), while no other variables showed significant differences (p < 0.05). Conversely, dental professors displayed significant differences in all variables analyzed (p < 0.05). In dental interns, gender was found to be the only influential variable, with females having a 41 % higher likelihood of perceiving disabled patient management poorly compared to males (APR = 1.41; 95 % CI: 1.04-1.91) (p = 0.028). However, gender was not found to be a significant factor for dental professors (p = 0.449). Conclusion: The majority of dental interns and professors had a poor perception of managing disabled patients, with no significant differences observed between them. Moreover, gender significantly influenced the perception of managing patients with physical disabilities among dental interns specifically. On the other hand, neither age, marital status, origin, professional experience, previous treatment of a patient with physical disability, nor previous cohabitation with a disabled patient were found to be associated factors among dental interns and professors.

Impact of an Educational Intervention on Oral Health Knowledge and Bacterial Plaque Control in Male Secondary School Students in a Peruvian Province: A Quasi-Experimental Study.

Background: The purpose of this study was to evaluate the effect of an educational intervention on oral health knowledge and bacterial plaque control in male secondary school students in a Peruvian province. Methods: This quasi-experimental study evaluated 294 male secondary school students in southern Peru. Oral health knowledge was measured with a validated 20-item questionnaire. Bacterial plaque was measured with the Simplified Oral Hygiene Index (OHI-S). This was rated as Excellent: 0, Good: 0.1-1.2, Fair: 1.3-3.0 and Poor: 3.1-6.0, before receiving the educational intervention and after four weeks of receiving it. Variables such as age, area of residence, having health professionals as family members, educational level of mother and father, and living with parents were considered. A significance level of p<0.05 was considered. Results: The comparison between the level of oral health knowledge and the OHI-S, before and after 4 weeks of receiving the educational intervention, showed a significant improvement (p<0.05) in all the categories of the variables studied. Likewise, before the educational intervention, there were significant differences in global knowledge about oral health among the categories of the following variables: age group (p=0.040), area of residence (p<0.001), educational level (father) (p=0.011) and living with parents (p<0.001). However, after four weeks of receiving the educational intervention, no significant differences were observed in all the variables studied (p>0.05). Regarding the OHI-S, no significant differences were observed in any of the variables studied, both before (p>0.05) and after four weeks (p>0.05) of receiving the educational intervention. Conclusion: After four weeks, the educational intervention significantly improved oral health knowledge and significantly reduced plaque bacterial plaque in male secondary school students in a Peruvian province, regardless of age, area of residence, having health professional family members, educational level of mother and father, and living with parents.

Tensile Strength and Elastic Modulus of Gutta-percha Cones Disinfected with Sodium Hypochlorite at Different Immersion Times: An In Vitro Comparative Study.

Aim: The tensile strength and modulus of elasticity of gutta-percha cones can be chemically altered due to disinfectant solutions. Therefore, the aim of the present study was to compare tensile strength and elastic modulus of gutta-percha cones subjected to sodium hypochlorite (NaOCl) disinfection at different times. Materials and Methods: This in vitro and longitudinal experimental study consisted of 45 gutta-percha cones, divided equally into three groups: Group 1 (disinfection with 2.5% NaOCl), Group 2 (disinfection with 5.25% NaOCl), and control group. All groups were subdivided according to immersion times for 1, 5, and 10 minutes. Tensile strength and elastic modulus were measured with a universal testing machine. For comparing more than two independent groups, parametric analysis of variance test with Sheffe's post hoc was used and for multivariate analysis, and multivariate analysis of variance test based on Pillai's Trace was used. In all statistical analysis, a significance level P ≤ 0.05 was considered. Results: When comparing the tensile strength of gutta-percha cones, no significant differences were observed after being immersed at 1, 5, and 10 minutes in NaOCl 2.5% (P = 0.715) and 5.25% (P = 0.585). Regarding the elastic modulus, a significant decrease (P < 0.05) was observed in those that were immersed in NaOCl 2.5% and 5.25% for 1, 5, and 10 minutes. Furthermore, increased NaOCl concentration significantly reduced the elastic modulus (P < 0.001). However, there were no significant differences in tensile strength (P > 0.05) and elastic modulus (P > 0.05), when evaluating the interaction between NaOCl concentration and time. Conclusion: Increasing NaOCl concentration significantly reduced the modulus of elasticity without affecting the tensile strength of gutta-percha cones, regardless of immersion time. Furthermore, the interaction of time and NaOCl concentration did not significantly affect the tensile strength and elastic modulus.

Comparative Evaluation of Microtensile Bond Strength in Three Different Dentin Luting Agents: An In vitro Study.

Aim: Long-term clinical success on indirect restorations is largely determined by bonding efficiency of the luting agent, with adhesion to dentin being the main challenge. Therefore, aim of this study was to assess the microtensile bond strength when using flowable resin composite, preheated resin composite and dual self-adhesive resin cement as dentin luting agents. Materials and Methods: Occlusal thirds of molar teeth were cut and randomly divided into 3 groups to be cemented: RelyX™U200, Filtek™ Z250 XT- preheated to 70° and Filtek Flow™ Z350XT. They were then thermocycled 5000 times between 5+/-2°C and 55+/-2°C. Subsequently, 10 microbars per group were prepared. The 30 samples were placed in saline solution for 24 hours at room temperature prior to microtensile test. This was performed with a digital universal testing machine at a crosshead speed of 0.5 mm/min. The bond strength values obtained were analyzed in Megapascals (MPa). Measures of central tendency such mean and measures of dispersion such standard deviation were used. In addition, the Kruskall Wallis non-parametric test with Bonferroni post hoc test was applied, considering a significance value of 5% (P < 0.05), with type I error. Results: The dentin microtensile bond strengths of preheated resin composite, flowable resin composite and dual self-adhesive cement were 6.08 ± 0.66 Mpa, 5.25 ± 2.60Mpa and 2.82 ± 1.26Mpa, respectively. In addition, the preheated resin composite exhibited significantly higher microtensile bond strength compared to the dual self-adhesive cement (P < 0.001). While the flowable resin composite showed no significant difference with the dual self-adhesive cement (P = 0.054) and the preheated resin composite (P = 0.329). Conclusions: The microtensile bond strength in dentin was significantly higher when using a preheated resin composite at 70°C as a luting agent compared to dual self-adhesive cement. However, the preheated resin composite showed similar microtensile bond strength compared to the flowable resin composite.

Sociodemographic Factors Associated with the Satisfaction Level of Peruvian Dental Students with Virtual Classes During the Covid-19 Pandemic: A Prospective Bicentric Study.

Background: The pandemic caused by Covid-19 impacted all areas of social, economic and educational activity. When there is a high risk of spreading highly infectious diseases, education is usually the first service to be suspended. The objective was to evaluate the sociodemographic factors associated with the satisfaction level of Peruvian dental students with virtual classes during the Covid-19 pandemic. Methods: This observational, cross-sectional, analytical study evaluated 237 dental students from the capital city and one Peruvian province using a validated 13-item questionnaire to measure the level of satisfaction with virtual classes. Pearson's chi-square test and a logit model were used to evaluate the associated factors such as age group, sex, marital status, monthly family income, area of residence, place of origin, occupation and computer use, considering a significance level of p<0.05. Results: Of all students, 50.6%, 40.1% and 9.3% presented a good, average and poor level of satisfaction, respectively, with the virtual classes received. In addition, those with a monthly family income of less than 500 US dollars were 3.15 times more likely to have poor satisfaction compared to those with a monthly family income of more than 1000 US dollars (AOR = 3.15; 95% CI: 1.23-8.05). The rest of the variables evaluated were not considered influential factors in the levels of satisfaction with the virtual classes received. Conclusión: Of all students, 50.6% and 9.3% reported good and poor satisfaction with virtual classes during the COVID-19 pandemic, respectively. Monthly family income of less than 500 US dollars was an influential factor. In addition, the variables age group, sex, marital status, area of residence, place of origin, occupation and computer use were not found to be influential factors.

Effect of Polywave and Monowave Light Curing Units on the Microtensile Bond Strength and Failure Types of Different Bulk-Fill Resin Composites: An in vitro Study.

Aim: This study aimed to evaluate the effects of polywave and monowave light-emitting diode curing units on the microtensile bond strength and failure types of three bulk-fill resin composites. Materials and Methods: This in vitro experimental study was performed on 180 microbars obtained from human third molars and were distributed into 12 groups according to the type of bulk-fill resin composite and the light-curing unit. Third molars were restored using Filtek One Bulk Fill Restorative, Tetric® N-Ceram Bulk Fill, and Opus Bulk Fill resin composites was light-cured with Elipar Deep Cure L and Valo in three modes: standard, high power, and extra power. Subsequently, microtensile analysis was carried out with a universal testing machine and the type of failure with an optical stereomicroscope. For statistical analysis, the Kruskal-Wallis H-test was used, with the Bonferroni post hoc test and Fisher's exact test, considering a significance of p<0.05. Results: There were significant differences in the microtensile bond strength between the Filtek One Bulk Fill restorative and Opus Bulk-Fill (p = 0.042) when light was cured with the polywave unit at standard power. On the other hand, the Filtek One Bulk Fill Restorative and Opus Bulk Fill resins showed significant differences in microtensile bond strength when light was cured with the monowave unit compared with the polywave unit (p<0.05). Conclusion: The presence of alternative photoinitiator systems that are more reactive than camphorquinone produced higher microtensile bond strength in Tetric N-Ceram Bulk Fill and Opus Bulk Fill resins when light-cured with a high and standard polywave unit, respectively, compared to Filtek One Bulk Fill resins. Finally, Tetric N-Ceram Bulk Fill and Opus Bulk Fill resins had the highest percentage of mixed failures, while Filtek One Bulk Fill resin had adhesive failures, which was related to its lower microtensile bond strength.

Microleakage of Class II Bulk-Fill Resin Composite Restorations Cured with Light-Emitting Diode versus Quartz Tungsten-Halogen Light: An In Vitro Study in Human Teeth.

Background: Resin composites undergo a certain degree of shrinkage when light-cured with different light sources available on the market, resulting in microleakage of dental restorations. The aim of the present study was to assess microleakage of class II restorations with bulk-fill resin composites cured with LED (light-emitting diode) and QTH (quartz tungsten-halogen light) units, both in cervical and occlusal areas of cavity preparations. Materials and Methods: In the present in vitro experimental study, a total of 30 human molar teeth were used, in which 60 class II cavities were prepared (mesial and distal) and restored with Filtek bulk fill resin composite. Restorations were equally distributed in 3 groups according to type of curing light: A, QTH (Litex 680A Dentamerica®); B, LED (Bluephase N® 3rd generation); and C, LED (Valo® 3rd generation). Each group was further subdivided into subgroups 1 and 2 according to IV-A or IV-B resin composite color. Restored teeth were subjected to 20,000 thermal cycles between 5° and 55 °C, then immersed in 1M silver nitrate solution for 24 h. Subsequently, the teeth were sectioned mesiodistally to obtain samples for observation under stereomicroscope in order to determine microleakage degree. Kruskal-Wallis H and Mann-Whitney U statistical tests were applied with a significance level of 5% (p < 0.05). Results: No statistically significant differences were found in the degree of microleakage of bulk-fill resin composites light-cured with LED and QTH units for both occlusal (p > 0.05) and cervical areas (p > 0.05). Additionally, no significant differences were found when comparing microleakage between occlusal and cervical areas (p > 0.05), regardless of lamp type. In addition, significant differences in microleakage degree were found between bulk-fill resins with IV-A and IV-B shades when they were light-cured with QTH at cervical level (p = 0.023). However, there were no significant differences when comparing these bulk-fill resin composite shades at occlusal level with LED (p > 0.05) and QTH (p > 0.05) units. Conclusions: Class II restorations with bulk-fill resin composite in IV-A and IV-B shades light-cured with third generation LED lamp and QTH showed no significant differences in microleakage when compared in both occlusal and cervical areas. On the other hand, significantly more microleakage was found at the cervical level when a darker shade of resin composite was used and light-cured with the QTH unit.

Microleakage in indirect onlay restorations cemented with three different types of adhesives: An in vitro study.

Background: To evaluate the in vitro degree of marginal microleakage in indirect Class II onlay restorations cemented with dual self-adhesive, universal adhesive and dual adhesive. Material and Methods: In the present in vitro experimental study, a total of 54 human premolar teeth were prepared and divided into three equal groups (n = 18) for placement of onlay-type restorations cemented with A: Allcem™ dual-cure adhesive cement), B: RelyX™U200 dual-cure self-adhesive cement and C: RelyX™ Ultimate universal adhesive cement. All restorations were subjected to 10,000 thermocycles between 5°C and 55°C and immersed in a 1M silver nitrate solution for 6 hours. The crowns were then sectioned mesiodistally and observed under a stereo microscope to determine the degree of marginal microleakage in the cervical area. Results: The onlay restorations cemented with RelyX Ultimate did not present microleakage in the majority of cases (77.8%). Restorations cemented with RelyX U200 showed predominantly microleakage up to the pulp floor in 83.3% of the total, being this significantly higher microleakage than in restorations cemented with RelyX Ultimate and Allcem Dual (p<0.001 and p<0.001 respectively). There was no significant difference in microleakage between the last two mentioned cements (p=0.255). Conclusions: Allcem dual adhesive cement and RelyX Ultimate universal adhesive showed significantly less microleakage than RelyX U200 dual-curing self-adhesive cement at the cervical level, with predominantly no microleakage and microleakage down to the enamel, respectively. The use of RelyX Ultimate cement in indirect restorations is recommended as it showed better marginal adaptation. Key words:Microleakage, human teeth, adhesion, adhesive cement, thermal cycling, onlay restoration.