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.

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.

Depression, Anxiety and Stress Associated With Fear of COVID-19 in Peruvian Dental Students: A Multivariate Analysis With 12 Sociodemographic Factors.

Aims and Objectives: Excessive fear of coronavirus disease 2019 (COVID-19) in dental students could cause mood disorders, especially if there are factors in the environment that generate feelings of anxiety or uncertainty. The aim of this study was to evaluate the fear of COVID-19 and its association with depression, anxiety, and stress in Peruvian dental students according to their sociodemographic factors. Materials and Methods: This analytical, observational, and cross-sectional study was conducted in 398 dental students of a public university in the Peruvian capital during April 2021 to July 2021. The Depression, Anxiety and Stress Scale-21 items was used to diagnose depression, anxiety, and stress. The Fear of COVID-19 Scale was used to detect fear of COVID-19. The Pearson's chi-square test was used for statistical analysis. In addition, a logit model using odds ratio (OR) was performed to evaluate depression, anxiety, and stress of students with the associated factors: fear of COVID-19 and 12 sociodemographic variables (gender, age group, marital status, year of study, origin, companion, living with vulnerable people, history of mental illness, history of COVID-19, loss of close relatives due to COVID-19, occupation, and area of residence). A significance level of P < .05 was considered. In addition, predictive models were developed for the variables depression, anxiety, and stress, considering all possible significant causes. Results: The prevalence of fear of COVID-19, depression, anxiety, and stress was 19.6%, 36.2%, 40.7%, and 19.6%, respectively. According to the adjusted logit model, students who had fear of COVID-19 had OR = 2.74 (95% confidence interval [CI]: 1.62-4.64), OR = 5.59 (95% CI: 3.14-9.97), and OR = 3.31 (95% CI: 1.88-5.83) for developing depression, anxiety, and stress, respectively. In addition, those who reported history of mental illness were four times more likely to develop depression (OR = 4.02, 95% CI: 1.96-8.25) and anxiety (OR = 4.50, 95% CI: 2.06-9.82), whereas those living with people vulnerable to COVID-19 were twice as likely to develop stress (OR = 2.06, 95% CI: 1.16-3.66). Conclusion: The highest prevalence of mood disorders among dental students was anxiety. In addition, those who were afraid of COVID-19 had three times the probability of developing depression and stress, and five times the probability of developing anxiety. On the other hand, the most influential factor in the development of depression and anxiety was history of mental illness, whereas the factor of living with vulnerable people was the most influential factor in the development of stress.

Bond Strength and Failure Mode of Glass Fiber Posts with Different Surface Treatments Prior to Silanization: An In Vitro Comparative Study.

Aim: The use of chemical agents in the surface treatment of glass fiber posts can improve their bond strength to the root canal. The aim of this study was to assess the bond strength and failure mode of glass fiber posts that received different surface treatments prior to silanization. Materials and Methods: In this cross-sectional and in vitro experimental study, 50 human lower premolar roots were randomly divided into five groups and subsequently prepared to receive the cementation of a fiberglass post prior to silanization. They were distributed as group 1 (with 24% hydrogen peroxide), group 2 (with 37% phosphoric acid), group 3 (with 1.23% acidulated phosphate fluoride for 2 minutes), group 4 (with 1.23% acidulated phosphate fluoride for 6 minutes), and group 5 (without pretreatment). After cementation, the roots were sectioned into two discs for each cervical, middle, and apical region. Bond strength was assessed using the push out technique. Adhesive, mixed, and cohesive failure modes were also assessed. For data analysis, ANOVA and Tukey's post hoc tests were used, as well as Pearson's chi-square test. A significance of P < 0.05 was considered in all statistical analyses. Results: When comparing the bond strength of root regions, significant differences were obtained in groups pretreated with phosphoric acid (P = 0.018) and acidulated phosphate fluoride for 2 and 6 minutes (P = 0.001 and P = 0.000, respectively). Furthermore, significant differences were obtained between posts treated only with silane and those that received phosphoric acid pretreatment (P = 0.006) and acidulated phosphate fluoride for 6 minutes (P = 0.001). Significant association of mixed failure mode was observed with hydrogen peroxide (P = 0.014) and phosphoric acid (P = 0.006) pretreatments. Cohesive failure was significantly associated with acidulated phosphate fluoride pretreatment for 2 minutes (P = 0.032) and with posts that did not receive treatment prior to silanization (P = 0.000). Conclusion: Posts treated only with silane and pretreated with hydrogen peroxide and acidulated phosphate fluoride for 2 minutes presented significantly higher bond strength with respect to those pretreated with phosphoric acid and acidulated phosphate fluoride for 6 minutes. However, acidulated phosphate fluoride for 2 minutes and silane were associated with a better bonding type.

Surface Roughness in Nanoparticle Resin Composites Subjected to Two Polishing Systems: An In vitro Comparative Study.

Aim: The surface roughness of dental restorations can decrease resin durability, since it leads to its deterioration, color variation, and loss of gloss. Therefore, the aim was to assess the surface roughness of nanoparticle resin composites, subjected to two different polishing systems. Materials and Methods: This longitudinal in vitro experimental study consisted of 32 resin specimens made according to ISO 4049-2019 and divided equally into four groups: A1: Palfique LX5 / Sof-Lex, A2: Palfique LX5 / Super Snap, B1: Filtek Z350 XT / Sof-Lex, and B2: Filtek Z350 XT / Super Snap. The samples were stored in distilled water at 37°C for 24 h. Surface roughness was measured with a digital roughness tester, both before and after the polishing procedure. The data were analyzed with the Student's t-test for related samples, and with the inter-subject ANOVA test with two factors; considering significance at P < 0.05. Results: The surface roughness of Palfique LX5 resin with the Sof-lex system was 0.330 (CI: 0.282-0.378 µm) and 0.170 (CI: 0.087-0.253 µm) before and after polishing, respectively. With the Super Snap system, values of 0.448 (CI: 0.346-0.549 µm) and 0.206 (CI: 0.130-0.282 µm) were obtained before and after polishing, respectively. For the Filtek Z350 XT resin, the surface roughness obtained with the Sof-lex system was 0.353 (CI: 0.278-0.427 µm) and 0.134 (CI: 0.095-0.172 µm) before and after polishing, respectively. With the Super Snap system, values of 0.334 (CI: 0.247-0.421 µm) and 0.171 (CI: 0.122-0.221 µm) were obtained before and after polishing, respectively. Surface roughness did not show significant differences in all groups assessed both before (P = 0.068) and after (P = 0.335) polishing. However, before and after the application of the polishing systems, all groups significantly decreased their surface roughness (P < 0.05). Further, when comparing this decrease among all groups, no significant differences were observed (P = 0.437). Conclusion: The surface roughness of the Filtek Z350 XT and Palfique LX5 nanoparticle resin composites showed no significant differences when using the Sof-lex and Super Snap polishing systems. However, both polishing systems significantly decreased the surface roughness of the nanoparticulated resins, with this decrease being similar in all groups.

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.

Patentes otorgadas a las universidades peruanas en el campo de la biomedicina. 2010 a 2020

Introducción: La patente es un título de propiedad industrial otorgado por el Estado al inventor de un nuevo producto o tecnología, susceptible de ser comercializado para obtener ganancias de forma exclusiva a un plazo de tiempo determinado. Objetivo: Determinar el número de patentes otorgadas a las universidades peruanas en el campo biomédico de 2010 a 2020, en comparación con la producción de otros inventores. Material y método: Este estudio descriptivo, observacional, retrospectivo y transversal analizó 73 patentes provenientes de un universo de 759, obtenidas de la base de datos del Instituto Nacional de Defensa de la Competencia y de la Protección de la Propiedad Intelectual en el Perú, de 2010 a 2020. Para comparar el número de patentes otorgadas a las universidades respecto a otros inventores, se aplicó la prueba del Chi Cuadrado de Pearson con la corrección de continuidad de Yates. Resultados: En el Perú, durante 2010 a 2020 se han otorgado 759 patentes, de las cuales 73 pertenecen al campo biomédico (9,61 %), de los cuales las universidades han generado 24,66 %; es decir 2,47 % del total. Además, las universidades presentaron diferencias significativas de producción de patentes (p = 0,019) en comparación a otros autores. Conclusiones: En el campo biomédico, la producción de patentes en las universidades peruanas ha sido muy limitadas desde 2010 a 2020. Además, las universidades presentaron significativamente menor producción de patentes en comparación a otros inventores, observándose que desde 2016, no se les ha otorgado ninguna patente de invención en el campo biomédico.

Introduction: A patent is an industrial property title granted by the State to the inventor of a new product or technology, susceptible of being marketed for profit on an exclusive basis for a determined period of time. Objective: To determine the number of patents granted to Peruvian universities in the biomedical field from 2010 to 2020, in comparison with the production of other inventors. Material and Methods: This descriptive, observational, retrospective and cross-sectional study analyzed 73 patents from a universe of 759 patents obtained from the database of the National Institute for the Defense of Competition and Protection of Intellectual Property in Peru, from 2010 to 2020. To compare the number of patents granted to universities with respect to other inventors, Pearson's chi-square test with Yates' continuity correction was applied. Results: In Peru, during the years 2010 to 2020, 759 patents have been granted, of which 73 belong to the biomedical field (9.61 %), of which universities have generated 24.66 %, i.e. 2.47 % of the total. Furthermore, universities showed significant differences in patent production (p = 0.019) compared to other authors. Conclusions: In the biomedical field, patent production in Peruvian universities has been very limited from 2010 to 2020. In addition, universities presented significantly lower patent production compared to other inventors, noting that since 2016, they have not been granted any invention patents in the biomedical field.

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.

Surface Microhardness of Bulk-Fill Resin Composites Handled With Gloves.

AIM: It has been reported that resin composites may experience alterations in their mechanical properties when they come into contact with glove powder. Therefore, the present study aimed to compare the surface microhardness of 3 bulk-fill resin composites handled with latex and nitrile gloves prior to light curing. METHODS: This in vitro experimental study consisted of 90 resin composite specimens with a 6-mm diameter and a 4-mm height divided equally and randomly into 9 groups. Prior to light curing, the resin composites were handled with latex gloves, nitrile gloves, or only a spatula (control). Subsequently, the surface microhardness was measured with an Electronic Vickers Hardness Tester. The Kruskal-Wallis nonparametric H test with Bonferroni correction was used for comparisons. A significance level of 5% (P < .05) was considered. RESULTS: When comparing surface microhardness of each resin composite according to type of handling received, significant differences were observed in Filtek One Bulk Fill (P < .001) and Opus Bulk Fill (P < .001). In addition, these resin composites presented significantly higher surface microhardness than Tetric N-Ceram Bulk Fill resin (P < .05) when handled with latex gloves, nitrile gloves, and only a spatula. Finally, Filtek Bulk Fill resin presented significantly higher surface microhardness compared to Opus Bulk Fill resin when handled with nitrile gloves (P = .038) and a spatula only (P = .033). CONCLUSIONS: The surface microhardness of Filtek One Bulk Fill and Opus Bulk Fill resin composites decreased significantly when handled with latex or nitrile gloves, showing no variation in Tetric N-Ceram Bulk Fill resin composite. In addition, Filtek One Bulk Fill resin composite showed significantly higher surface microhardness than Opus Bulk Fill and Tetric N-Ceram Bulk Fill resin composites when handled with nitrile gloves. It is recommended that bulk-fill resin composites be handled with a spatula, because the use of latex or nitrile gloves could adversely affect their clinical performance.

Adhesive Strength in Dentin Conditioned with 18% Ethylenediaminetetraacetic Acid versus 35% Phosphoric Acid: In Vitro Study with 1-Year Artificial Aging.

The success and longevity of a resin composite restoration is determined by its good bonding to the tooth structure, with the adhesion being a challenge to dentin due to its complexity and structural heterogeneity. The present study aimed to compare the adhesive strength of dentin conditioned with 18% ethylenediaminetetraacetic acid (EDTA) versus 35% phosphoric acid (H3PO4) in human premolars. Materials and Methods: This in vitro experimental study was performed on 40 human premolars. The occlusal thirds were sectioned and randomly placed into four groups according to the type of dentin conditioning: Group 1 (control), Group 2 (18% EDTA), Group 3 (35% H3PO4) and Group 4 (18% EDTA plus 35% H3PO4). Then, 10,000 thermocycles between 5 +/− 2 °C and 55 +/− 2 °C were applied. Adhesive strength was tested by shearing with a digital universal testing machine at a crosshead speed of 0.75 mm/min. The values obtained were analyzed in megapascals (MPa). The mean and standard deviation were used as measures of central tendency and dispersion. In addition, a one-factor intergroup ANOVA test was applied with Tukey's post hoc test considering a significance level of p < 0.05. Results: The 18% EDTA and 18% EDTA plus 35% H3PO4 showed significantly higher adhesive strength compared to the control group that did not receive dentin conditioning (p = 0.047 and p < 0.001, respectively). However, the group conditioned with 18% EDTA did not present significant differences compared to the group conditioned with 35% H3PO4 (p = 0.997). In addition, the group conditioned with 18% EDTA plus 35% H3PO4 showed significantly higher adhesive strength compared to the groups conditioned with 18% EDTA (p = 0.002) and 35% H3PO4 (p = 0.001). Conclusion: The adhesion of bulk fill resin composite to dentin was favorable when preconditioning was performed using 18% EDTA followed by 35% H3PO4. In contrast, when both etchants were used separately, the bulk fill resin composite showed similar bond strength values in both cases, but significantly lower compared to their sequential application.

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.

The Microhardness and Surface Roughness Assessment of Bulk-Fill Resin Composites Treated with and without the Application of an Oxygen-Inhibited Layer and a Polishing System: An In Vitro Study.

The aim of this study was to assess the microhardness and surface roughness of bulk-fill resin composites treated with and without the application of an oxygen-inhibited layer (OIL) and a polishing system. This in vitro experimental study consisted of 72 resin composite blocks divided into three groups: Tetric N-Ceram Bulk Fill, Opus Bulk Fill APS, and Filtek Bulk Fill. Each resin composite group was further divided into two subgroups: with and without OIL control. Subsequently, surface roughness and microhardness were measured before and after polishing. A t-test was used to compare independent and related measures. For the intergroup comparison of variation before and after polishing, the Kruskal−Wallis test with Bonferroni post hoc was used considering a significance level of p < 0.05. When comparing surface roughness, significant differences were observed between Opus Bulk Fill resin composite with and without OIL control (p = 0.003) before polishing. The same occurred when comparing Tetric N-Ceram resin composite with and without OIL control (p = 0.039) after polishing. In addition, the surface roughness of Filtek Bulk Fill, Opus Bulk Fill, and Tetric N-Ceram Bulk Fill resin composites, with and without OIL control, decreased significantly after polishing (p < 0.001), while surface microhardness significantly increased (p < 0.05), with the exception of Opus Bulk Fill resin with OIL control (p = 0.413). In conclusion, OIL control and polishing significantly improved the surface roughness and surface microhardness of Filtek Bulk Fill and Tetric N-Ceram Bulk Fill resin composites. However, in the case of Opus Bulk Fill resin composite, only its surface roughness was significantly improved.

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.

Predictability and Accuracy of the Short-Form Fonseca Anamnestic Index in Relation to the Modified Helkimo Index for the Diagnosis of Temporomandibular Disorders: A Cross-Sectional Study.

Aim: The aim of this study was to evaluate the predictability and accuracy of the Short-Form Fonseca Anamnestic Index (SFAI) in relation to the modified Helkimo Index for the diagnosis of temporomandibular disorders (TMDs). Materials and Methods: A cross-sectional, prospective, and analytical predictive study was conducted in 240 students of a public institute of higher technological education in Ica, Peru during the months of February to May 2018. The SFAI of 10 closed questions and the Helkimo Index modified by Maglione (gold standard) were used as instruments to diagnose TMDs. For the analysis of concordance between both instruments, Cohen's Kappa Index was applied. To evaluate the association according to gender and age group, Pearson's chi-square test was used. For validity of the SFAI in relation to accuracy, sensitivity and specificity were calculated, and they were verified by receiver operating characteristics (ROC) to determine the best cutoff points (area under the curve [AUC]) considering a P value < 0.05. Regarding the predictability of the SFAI, the positive and negative predictive value was calculated by applying Bayes' theorem. Results: The SFAI was highly significantly associated with the modified Helkimo Index according to gender (P < 0.001), age group (P < 0.001), and overall (P < 0.001) moderate overall agreement (k = 0.416; 95% confidence interval [CI] = 0.287-0.545); better concordance was obtained in individuals older than 20 years (k = 0.490, CI = 0.302-0.679) and women (k = 0.565, CI = 0.371-0.759). The ROC curve analysis of the SFAI showed good accuracy (0.852, CI = 0.800-0.905) and was highly significant (P < 0.001), with an optimal cutoff point of 17.5 and good sensitivity (80.10%) and specificity (74.36%). In addition, a very good positive predictive value (PPV) (94.15%) and a fair negative predictive value (NPV) (42.02%) were obtained. Conclusions: Although there was moderate concordance between the SFAI and the modified Helkimo Index for the diagnosis of TMDs, the SFAI obtained good accuracy in the overall analysis of sensitivity and specificity. In addition, it demonstrated a high predictive efficacy for detecting positive TMD cases, whereas its ability to rule out positive cases was fair.

Psychological distress facing the COVID-19 pandemic in dental interns from the Peruvian capital: A cross-sectional study under a multivariable regression model.

Aim: Psychological distress can be considered a maladaptive response to a stressful situation that occurs when external events or stressors impose demands that cannot be coped with. Therefore, the aim of the present study was to evaluate the sociodemographic factors associated with psychological distress in dental interns from the Peruvian capital facing the COVID-19 pandemic. Materials and methods: This analytical, observational, cross-sectional study was conducted on 392 Stomatology interns from the Peruvian capital from June to July 2022. The validated COVID-19 Peritraumatic Distress Index (CPDI) scale to detect the levels of psychological distress consisted of four dimensions: negative mood, changes in behavior and cognitive skills, fatigue and hyperreactivity, and somatization. Pearson's chi-square and Fisher's exact test were used for bivariable analysis. In addition, a logit model was used to assess the influence of variables: sex (X1), age group (X2), marital status (X3), monthly economic income (X4), working area in the capital city (X5), and living with people vulnerable to COVID-19 (X6), with the psychological distress levels, considering a significance p < 0.05. Results: The prevalence of psychological distress in dental interns was severe in 6.4% [95% confidence interval (CI): 3.9-8.8%] and mild in 37.8% (95% CI: 33.0-42.6%). According to bivariable analysis, the levels of psychological distress by COVID-19 were not significantly associated with sex (p = 0.190), age group (p = 0.418), marital status (p = 0.554), monthly economic income (p = 0.327), working area in the capital city (p = 0.993), and living with people vulnerable to COVID-19 (p = 0.134). In addition, according to the logistic regression analysis, none of the variables studied was considered an influential factor (p > 0.05) in psychological distress presented by dental interns. Conclusion: The 44.2% of dental interns from the Peruvian capital presented psychological distress facing the COVID-19 pandemic, without any of the possible associated variables of this study significantly affecting this behavioral disorder.

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.

Effect of 16% Carbamide Peroxide and Activated-Charcoal-Based Whitening Toothpaste on Enamel Surface Roughness in Bovine Teeth: An In Vitro Study.

Background: Activated charcoal is a nanocrystalline form of carbon with a large specific surface area and high porosity in the nanometer range, having consequently the capacity to absorb pigments, chromophores, and stains responsible for tooth color change, while carbamide peroxide is unstable and breaks down immediately upon contact with tissue and saliva, first dissociating into hydrogen peroxide and urea and subsequently into oxygen, water, and carbon dioxide. Therefore, the aim of the present study was to assess the effect of 16% carbamide peroxide and activated-charcoal-based whitening toothpaste on enamel surface roughness in bovine teeth. Materials and Methods: The present experimental in vitro, longitudinal, and prospective study consisted of 60 teeth randomly distributed in six groups: A: artificial saliva, B: conventional toothpaste (Colgate Maximum Protection), C: whitening toothpaste with activated charcoal (Oral-B 3D White Mineral Clear), D: 16% carbamide peroxide (Whiteness Perfect 16%), E: 16% carbamide peroxide plus conventional toothpaste (Whiteness Perfect 16% plus Colgate Maximum Protection), and F: 16% carbamide peroxide plus whitening toothpaste with activated charcoal (Whiteness Perfect 16% plus Oral-B 3D White Mineral Clear). Surface roughness was assessed with a digital roughness meter before and after each treatment. For the statistical analysis, Student's t test for related samples was used, in addition to the ANOVA test for one intergroup factor, considering a significance level of p < 0.05. Results: The surface roughness variation of bovine tooth enamel, before and after application of bleaching agent, was higher in groups of whitening toothpaste with activated charcoal (0.200 µm, Confidence Interval (CI): 0.105; 0.296 µm) and 16% carbamide peroxide plus whitening toothpaste with activated charcoal (0.201 µm, (CI): 0.092; 0.309 µm). In addition, bovine teeth treated with conventional toothpaste (p = 0.041), whitening toothpaste with activated charcoal (p = 0.001), and 16% carbamide peroxide plus whitening toothpaste with activated charcoal (p = 0.002) significantly increased their surface roughness values. On the other hand, significant differences were observed when comparing the variation in surface roughness between the application of artificial saliva (control) and the whitening toothpaste with activated charcoal (p = 0.031), and the 16% carbamide peroxide plus whitening toothpaste with activated charcoal (p = 0.030). Conclusion: The use of whitening toothpaste with activated charcoal and in combination with 16% carbamide peroxide significantly increased enamel surface roughness in bovine teeth.

Association Between Periodontal Disease and the Risk of COVID-19 Complications and Mortality: A Systematic Review.

AIM: The COVID-19 pandemic has strained the world's healthcare systems. Studies have identified how the COVID-19 infections are linked to several co-morbidities such as hypertension, diabetes, cardiovascular disease, renal and pulmonary disease. It is known that periodontal disease (PD) shares the same risk factors. Moreover, both diseases are characterized by an exaggerated immune response. The aim of the study was to investigate the available evidence of a potential association between PD and the risk of COVID-19 complications and mortality. MATERIALS AND METHODS: MEDLINE/PubMed, EMBASE, Scopus, and ProQuest were searched. Studies that assess the association between PD and the risk of COVID-19 complications and mortality were eligible for inclusion. Two independent reviewers performed the selection of articles and data extraction. The New Castle Ottawa Scale was used to assess the quality of the selected studies, and the GRADE system was used to evaluate the level of confidence to support the conclusions. RESULTS: Only two studies met the eligibility criteria. One study had a low risk of bias, whereas the other had a high risk of bias. CONCLUSION: The level of confidence in the available evidence is very low. A close association between periodontitis and the risk of COVID-19 complications and mortality can neither be supported nor refuted.

Evaluation of Buccal Bone Wall Thickness of Anterosuperior Teeth and Nasopalatine Duct Morphology in Cone Beam Computed Tomography of Patients Living at Different Altitudes: A Two-Year Retrospective Study.

AIM: To evaluate the buccal bone wall thickness of anterosuperior teeth and the dimension and morphology of the nasopalatine duct in cone beam computed tomography (CBCT) of patients treated in two cities at different altitudes. MATERIALS AND METHODS: In this retrospective analytical study, 79 CBCT scans were selected from a total of 347 in Juliaca, Peru (3824 m a.s.l.) and 171 CBCT scans were selected from a total of 622 in Lima, Peru (154 m a.s.l.). The buccal bone wall thickness of anterosuperior teeth was measured at 1 mm, 3 mm, and 5 mm from the alveolar crest. For the nasopalatine duct, its length and diameter were measured, and its anatomical shape was determined in coronal view. Descriptive statistical data such as mean and standard deviation were used, and Mann-Whitney U test was used for bivariate analysis. RESULTS: When comparing the CBCT scans from both cities, significant differences were observed in buccal bone wall thickness at 3 mm and 5 mm from the alveolar crest (P < 0.01 and P < 0.01, respectively); for men, at 1 mm and 3 mm (P = 0.04 and P = 0.04); for the age group from 33 to 47 years, at 3 mm and 5 mm (P < 0.01 and P < 0.01); and for the age group from 48 to 77 years, at 1 mm (P = 0.02). Regarding the nasopalatine duct, significant differences were observed in women in relation to length and nasal opening diameter (P < 0.01 and P < 0.01) and for men, in length (P < 0.01); for the age group from 18 to 32 years, in all three levels (P < 0.01); for the age group from 33 to 47 years, in length and diameter of the oral opening (P < 0.01 and P < 0.01); and for the age group from 48 to 77 years, in length and diameter of the nasal opening (P < 0.01 and P < 0.01). The most frequent nasopalatine duct shape was a single canal with more than 66% of cases, according to sex and age group. CONCLUSION: Patients living at different altitudes presented significant differences in buccal bone wall thickness according to sex and age; however, there were no differences related to dental inclination. Significant differences were found in the length and diameter of the nasopalatine duct at the nasal opening. In addition, the most frequent shape of the nasopalatine duct was the simple canal.