Effect of degree of conversion on the surface properties of polymerized resin cements used for luting glass fiber posts.

STATEMENT OF PROBLEM: Lack of conversion of resin cements for luting glass fiber posts in deeper levels of the root canal may compromise clinical performance. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the degree of conversion on the surface properties of dual-polymerized resin cements used for cemented glass fiber posts according to the root level. MATERIAL AND METHODS: Fifty maxillary central incisor teeth were endodontically treated, and glass fiber posts were cemented using the following systems: self-adhesive dual-polymerized resin luting cement (RelyX U200) and dual-polymerizing flowable core and a post luting system (Rebilda DC) with a self-etching adhesive (Futurabond DC). The degree of conversion was determined via attenuated total reflectance and Fourier transform infrared spectroscopy, and surface microhardness and cement film thickness were measured. The intraradicular fit was evaluated with microscopy. All tests were performed in the coronal, middle, and apical third of the root canal. Statistical analysis was done with ANOVA and the multiple comparison Tukey test (α=.05). RESULTS: The degree of conversion was higher in the coronal third using Rebilda DC (65.3 ±4.8%) than RelyX U200 (38.7 ±5.3%) (P<.05); on both resin cements, these values decreased from the coronal to the apical third (30.9 ±3.7%, 61.9 ±8.7%, respectively). The cement film thickness was higher for RelyX U200 in the 3 thirds than for Rebilda DC; significant differences (P<.05) were recorded in both cementing systems in the coronal and apical thirds. In the middle third, no significant differences were observed (P>.05). The mean surface microhardness values increased in the coronal thirds and decreased with increasing root canal depth. The marginal seal in the coronal thirds and the intraradicular fit in the middle thirds showed closer adaptation; however, some tags were observed in the interface resin cement and radicular dentin. Gap and tag formations were observed in the apical third. CONCLUSIONS: Depending on the root canal third, the surface properties of dual-polymerized resin cements are influenced by the degree of conversion.

Effect of short fiber-reinforced composite combined with polyethylene fibers on fracture resistance of endodontically treated premolars.

STATEMENT OF PROBLEM: Whether direct coronal restorations of endodontically treated teeth with short fiber-reinforced composite combined with polyethylene fibers provide adequate mechanical strength is unclear. PURPOSE: The purpose of this in vitro study was to compare the fracture strength of endodontically treated premolars with standardized mesio-occluso-distal (MOD) preparations restored with short fiber-reinforced composite (SFRC) combined with polyethylene Ribbond fibers (PRFs). MATERIAL AND METHODS: A total of 40 premolars were selected and distributed into 4 groups (n=10) as follows: group restored with SFRC (EverX Posterior), group restored with PRF (Ribbond fibers), and group restored with the combination PRF+SFRC, all followed by a conventional composite resin (IPS Empress Direct). MOD preparations and endodontic treatments were prepared except in the control group (intact teeth). MOD preparations and endodontic treatments were prepared except in the control group (intact teeth). Specimens were loaded using a universal testing machine until fracture occurred at a crosshead speed of 0.5 mm/min, and the failure type and fracture patterns was reported descriptively. The mean values of the groups were analyzed by using the Shapiro-Wilk test and 1-way ANOVA tests (α=.05). RESULTS: Restoration with PRF+SFRC provided the highest mean ±standard deviation fracture resistance (288.2 ±73.5 N). Restoration with just PRF had the lowest values (192.4 ±25.4 N), which were statistically different from those of SFRC and PRF+SFRC (P<.05). The predominant mode of failure was mixed, and all fracture patterns were favorable. CONCLUSIONS: Reinforcing endodontically treated premolars with MOD cavities with Ribbond fibers followed by a conventional composite resin enhanced fracture resistance and may be suitable for the direct coronal restoration of large posterior cavities in stress-bearing areas.

Knowledge about COVID-19 and perception of health safety among mexican dental students / Conocimiento sobre COVID-19 y percepción de seguridad en la salud de estudiantes mexicanos de odontología

This study aimed: 1) to investigate sources of information used by students to learn about COVID-19, 2) to investigate levels of knowledge about COVID-19 and about conditions for the treatment of patients during the COVID-19 lockdown, and 3) to evaluate students' perceptions of safety regarding their return to in-person activities at the School of Dentistry. Dental students answered a questionnaire (29 items; n=371) that explored the aims of the study, based on a Likert scale (Cronbach's alpha, 0.778). Data were tested with the Mann-Whitney U test and Kendall's Tau-c. Dental students received information about COVID-19 from the Mexican Health Ministry as their first source (45.28%). Students had good knowledge about the main characteristics of COVID-19, and 59.3% of students had excellent knowledge about the factors relevant to dental treatment of patients. Half of the students said they felt safe regarding a possible return to in-person activities at the dental school, while the other half did not. Statistically significant differences were noted between the students' scholar year and their level of knowledge (P<0.001) and between their perception of safety (very unsafe, unsafe, safe, and very safe) and scholar year (P=0.000). Dental students had good knowledge about COVID-19 and about the dental care for patients during the lockdown. Half of the dental students felt unsafe about a possible return to in-person school activities.

Los objetivos del estudio fueron 1) investigar que fuentes de información usaron los participantes para conocer sobre la COVID-19, 2) evaluar cuál es el nivel de conocimiento que tienen sobre COVID-19 y la atención a pacientes durante la contingencia, y 3) evaluar la percepción de seguridad sobre el regreso a actividades presenciales en la facultad. Estudio transversal. Se aplicó un cuestionario en línea (29 ítems; n=371) que exploró cada objetivo e incluyó una escala de Likert (Alfa de Cronbach de 0.778). Los datos fueron analizados con las pruebas de U de Mann Whitney y con Tau-c de Kendall. La mayoría de los participantes obtuvieron información sobre la COVID-19 a través de la Secretaría de Salud (45.28%), tuvieron un conocimiento bueno sobre las generalidades de la COVID-19 y el 59.3% tuvo un conocimiento excelente sobre la atención a pacientes. La mitad de los encuestados tuvo una percepción de inseguridad en un posible regreso a actividades en la facultad. Hubo diferencia estadística significativa para la asociación entre año escolar y grado de conocimiento (p<0.001) y entre la percepción en la seguridad en el regreso a actividades (muy inseguro, inseguro, seguro y muy seguro) y el grado escolar (P=0.000). Los participantes tuvieron buen conocimiento sobre las generalidades de la COVID-19 y sobre la atención a pacientes en situación de contingencia. La mitad de los EO sienten inseguridad sobre un posible regreso a actividades.

The impact of two root canal treatment protocols on the oral health-related quality of life: a randomized controlled pragmatic clinical trial.

AIM: To assess the impact of two root canal treatment protocols on the oral health-related quality of life (OHRQoL) of patients in need of root canal treatment on their anterior teeth. METHODOLOGY: The sample consisted of 120 participants (mean age: 34 years) enrolled in a pragmatic randomized clinical trial evaluating two root canal treatment protocols. Anterior teeth with nonvital pulps were allocated for root canal preparation with either hand files and filled with lateral compaction of gutta-percha (manual protocol) or canal preparation with a single file in a reciprocating movement and filled with a single cone technique (Reciproc protocol). OHRQoL data were assessed using the Oral Health Impact Profile instrument (OHIP-14), which was administered before the root canal intervention (baseline), and 6 and 12 months after treatment. Demographic and clinical characteristics of participants were collected at baseline. Data were analysed using bivariate analyses, Poisson univariate and multiple regression (α = 0.05). RESULTS: The drop-out rate from baseline was 27% and 28% at 6 and 12 months after treatment, respectively. Both root canal protocols significantly enhanced patients' OHRQoL, regardless of the follow-up time (P < 0.001). After 6 months, patients treated with the Reciproc protocol had significantly lower OHIP-14 overall scores (P = 0.030), as well as significantly lower scores for psychological discomfort (P = 0.031) and social disability (P = 0.013). After 12 months, no significant difference was observed between the two root canal protocols for OHIP-14 overall scores (P = 0.174). Either large or moderate effect sizes were observed for all domains and overall scores at both evaluation times, irrespective of the protocol. Low-income persons (RR = 2.03) and the Reciproc protocol (RR = 1.52) had a higher likelihood of a positive impact on OHRQoL 12 months after root canal treatment. CONCLUSIONS: The two root canal protocols improved the OHRQoL and differences in scores were observed only after 6 months with poorer OHRQoL for the manual protocol. After 12 months, patients with low-income status and treated with Reciproc were associated with a greater improvement in OHRQoL scores.

Learning of the mental nerve block technique with dental anaesthesia simulation models builds motor skills and confidence in dental students.

INTRODUCTION: We compared the motor learning, self-confidence whilst performing an anaesthesia technique and the perception of confidence between a group of students trained (G1) with two distinct dental anaesthesia simulation models (DASM) and a group of students (G2) not trained with DASM. MATERIALS AND METHODS: The G1 students (n = 22) were trained with a learning protocol including a DASM for simulating a puncture and a DASM for simulating an injection of dental anaesthesia. The G2 students (n = 22) received no such training. Both groups performed the mental nerve block (MNB) in a clinical setting, after which the average working time (motor learning), number of times help was requested for performing the MNB (self-confidence) and the scores of a Likert Scale questionnaire (perception of confidence) between the groups were compared with a t test. RESULTS: Compared with G2, the G1 students showed a shorter average working time (G1, 7:30 ± 0:54 min; G2, 9:06 ± 2:27 min; P = .017). Hence, G1 students had better motor skills. They also requested help when performing the MNB fewer times than the G2 students (G1, 2.2 ± 0.5 times; G2, 4.6 ± 1.95 times; P < .001). On the other hand, the G1 students demonstrated better perception of confidence (Likert Scale questionnaire) when performing the MNB compared with the G2 students (P = .007). CONCLUSION: The learning protocol with two different DASMs had a positive effect on the motor skills and the confidence of dental students performing the mental nerve block.

Impact of Two Distinct Dental Anesthesia Simulation Models on the Perception of Learning by Students / Impacto de dos distintos modelos de simulación para anestesia dental en la percepción del aprendizaje en estudiantes

ABSTRACT We evaluated an infiltration anesthesia simulation model (IAM) and a conduction anesthesia simulation model (CAM) on the perception of learning by Mexican dental students. Our aim was to compare the perception of learning by dental students trained with two distinct dental anesthesia simulation model (DASM) with dental students who were not trained with a DASM. 3 groups participated in the study: G1 (N=12 students) learned to block the mental nerve (BMN) by participating in a theoretical lecture (stage 1) and a clinical demonstration (stage 2); G2 (N=12 students) learned the BMN by participating in the stage 1, stage 2, and training with the CAM; G3 (N=12 students) learned the BMN by participating in the stage 1, stage 2, and training with the IAM. The groups performed the BMN in a clinical exercise. Working-time of all participants was timed. Perception of learning for all participants was evaluated with a 5-point Likert Scale. The results showed that statistically significant differences were found between score of G1 and score of G2 and score of G3 (P<0.05). No statistically significant differences were found between scores of G2 and scores of G3. G1, G2 and G3 showed an average working-time of 12:42 minutes, 9.75 minutes and 8:03 minutes, respectively (P<0.05). We concluded that the IAM and CAM showed a positive impact on the perception of learning, and the students trained with the IAM showed a shorter working time compared with the students trained with the CAM.

RESUMEN En este estudio se evaluó el impacto de un modelo de simulación de anestesia dental por infiltración (IAM) y de un modelo de simulación de anestesia dental por bloqueo (CAM) en la percepción del aprendizaje en estudiantes mexicanos en estomatología. El objetivo fue comparar la percepción en el aprendizaje de estudiantes que entrenaron empleando dos distintos modelos de simulación de anestesia dental con estudiantes que no recibieron entrenamiento empleando algún modelo de simulación de anestesia dental. Participaron 3 grupos en el estudio: G1 (n=12) aprendieron el bloqueo del nervio mentoniano (BNM) al participar en una clase teórica (sesión 1) y en una demostración clínica (sesión 2); G2 (n=12) aprendieron la técnica de anestesia del BNM al participar en la sesión 1, sesión 2 y entrenando con el CAM; G3 (n=12) aprendieron la técnica del BNM al participar en la sesión 1, sesión 2 y entrenando con el IAM. Los grupos aplicaron la técnica del BNM en un ejercicio clínico. Se midió el tiempo de trabajo de los participantes. La percepción del aprendizaje de los participantes se evaluó con una Escala de Likert de 5 ítems. Los resultados mostraron diferencias estadísticamente significativas entre los valores del G2 y del G3 en comparación con el G1. No se encontraron diferencias estadísticas entre los valores del G2 y del G3. El tiempo de trabajo para el G1, G2 y G3 fue respectivamente de: 12:42 minutos, 9.75 minutos y 8:03 minutos, (P<0.05). Se concluyó que el IAM y el CAM mostraron un impacto positivo en la percepción del aprendizaje; los estudiantes entrenados con el IAM mostraron un tiempo de trabajo más corto en comparación con los estudiantes entrenados con el CAM.

Oral health related quality of life and determinant factors in patients with head and neck cancer.

BACKGROUND: The present study aimed to measure the impact of oral health on the quality of life of patients with head and neck cancer. MATERIAL AND METHODS: A cross-sectional study was conducted with 130 patients diagnosed with head and neck cancer at two medical centers. Participants answered a sociodemographic questionnaire and the Oral Health Impact Profile - 14 (OHIP-14). Clinical aspects, cancer staging, and treatment approach were also investigated. Mann-Whitney and Kruskal-Wallis non-parametric tests were used for statistical analysis, followed by Poisson regression analysis (with robust error variance), to associate the OHIP-14 scores with independent variables. RESULTS: The OHIP-14 presented good internal consistency (Cronbach's Alpha = 0.861). The mean score obtained was 19.52 (±11.79). Physical pain (3.70±2.44), physical disability (3.26±2.62) and functional limitation (3.24±2.45) were ranked as the main factors affecting the quality of life. Patients non-Caucasians (PR = 1.30; IC 95% = 1.07-1.58; p = 0.009), widowers (PR = 1.36; IC 95% = 1.13-1.64; p = 0.001), diagnosed with squamous cell carcinoma (PR = 1.28; IC 95% = 1.05-1.58; p = 0.017) and with temporomandibular pain (PR = 1.31; IC 95% = 1.08-1.60; p = 0.007) were more likely to exhibit lower rates of quality of life. CONCLUSIONS: The results showed a high impact of the oral health in the quality of life of patients with head and neck cancer was observed. Sociodemographic and clinical characteristics can exert influence on the quality of life of patients with head and neck cancer.

[Frequency of footprints alterations in school children from a Mexican community]. / Frecuencia de alteraciones de la huella plantar en escolares de una comunidad mexicana.

INTRODUCTION: Alterations in the plantar footprint in the child are a cause for concern in parents. OBJECTIVE: Determine the frequency of plantar footprint alterations in school children. Determine if there is a relationship between overweight and obesity with the presence of alterations of the plantar footprint. MATERIAL AND METHODS: Observational, transversal and prospective study. 959 schoolchildren aged six to 13 were evaluated. Weight, size, body mass index for age were recorded. The plantar footprint was cataloged on flat foot and cavus foot using the arch index. For statistical analysis and comparison, the SPSS version 24 program was used with the 2 and ANOVA tests. RESULTS: 530 children (55.3%) and 429 girls (44.7%). The median age was 8.97 years. 182 children were found (19%) with alteration of the plantar footprint, 42.3% with flat foot and 57.7% with cavus foot. None of them had foot symptoms. 131 children were overweight and 52 obese, without influencing the presence of any alteration of the plantar footprint (p = 0.20). The flat-foot ratio was higher in men (2.5:1) and standing cavus major in women (1.3:1). CONCLUSIONS: In our study group we find a higher prevalence of the cavus foot compared to the flat foot. Body weight did not influence plantar footprint alterations.

INTRODUCCIÓN: Las alteraciones de la huella plantar en el niño es causa de preocupación en los padres de familia. OBJETIVO: Determinar la frecuencia de alteraciones de la huella plantar en escolares. Determinar si existe relación entre el sobrepeso y la obesidad con la presencia de alteraciones de la huella plantar. MATERIAL Y MÉTODOS: Estudio observacional, transversal y prospectivo. Se evaluaron 959 escolares de seis a 13 años de edad. Se registró peso, talla, índice de masa corporal para la edad. La huella plantar se catalogó en pie plano y pie cavo utilizando el índice del arco. Para el análisis y comparación estadística se utilizó el programa SPSS versión 24 con las pruebas 2 y ANOVA. RESULTADOS: Se revisaron 530 niños (55.3%) y 429 niñas (44.7%). La media de edad fue de 8.97 años. Se observaron 182 niños (19%) con alteración de la huella plantar, 42.3% con pie plano y 57.7% con pie cavo. Ninguno mostró sintomatología del pie. Ciento treinta y un niños tenían sobrepeso y 52 obesidad, sin influir en la presencia de alguna alteración de la huella plantar (p = 0.20). La relación de pie plano fue mayor en los hombres (2.5:1) y de pie cavo fue mayor en las mujeres (1.3:1). CONCLUSIONES: En nuestro grupo de estudio se encontró mayor prevalencia del pie cavo en comparación con el pie plano. El peso corporal no influyó en las alteraciones de la huella plantar.

Association between impacted third molars and position of the mandibular canal: a morphological analysis using cone-beam computed tomography.

Our aim was to assess the association between the angle of impaction of the third molar and the position of the mandibular canal on cone-beam computed tomography (CT). We designed a retrospective study of 100 cone-beam CT images of 173 mandibular third molars that were obtained between January 2012 and December 2015, and recorded the angle of impaction of the third molar, the position of the mandibular canal in relation to the impacted tooth, and the potential contact between the roots of the tooth and the mandibular canal. Most third molars tilted mesially (n=33), while the mandibular canal was positioned below the roots of the third molar in most cases (n=73). Contact between the two was most likely when the mandibular canal was between (RR=1.49; 95% CI 1.27 to 1.75, p<0.001), or to the lingual side (RR=1.49; 95% CI 1.27 to 1.75, p<0.001) of the roots of the tooth. These outcomes indicate a greater likelihood of contact between the canal and the roots when the canal is between, and to the lingual side, of the roots. We found no association between the angle of impaction and the position of the canal. These findings illustrate the importance of surgical planning using complementary imaging tests such as cone-beam CT.

Multiple correspondence analysis as a strategy to explore the association between categories of qualitative variables related to oral-maxillofacial trauma and violent crimes at the community level.

The main objective of this study was to show the applicability of multiple correspondence analysis (MCA) in the detection and representation of underlying structures in large datasets used to investigate oral-maxillofacial lesions. A cross-sectional study was conducted involving the analysis of the medical-forensic and social records of 992 people who experienced oral-maxillofacial trauma resulting from non-fatal violent crimes that occurred in the community. Based on the MCA results, two distinct victim profiles were identified. The first profile was characterized by adult men, victims of instruments of violence (such as firearms, knives, or mixed aggression), resulting in severe trauma, mainly affecting the upper or middle third of the face. The second profile was characterized by adolescent and young adult women, victims of aggression using physical force, resulting in soft tissue traumas, mainly affecting the lower third of the face or more than one region at the same time. MCA has been demonstrated to be a powerful tool for exploring complex data related to oral-maxillofacial trauma, showing whether there is a relationship and how variables are related. This multivariate method can also be very valuable in the study of several outcomes in oral and maxillofacial surgery and supporting specialties.

Systemic lupus erythematosus in Europe at the change of the millennium: lessons from the "Euro-Lupus Project".

The "Euro-Lupus Cohort" is composed by 1000 patients with systemic lupus erythematosus (SLE) that have been followed prospectively since 1991. These patients have been gathered by a European consortium--the "Euro-Lupus Project Group". This consortium was originated as part of the network promoted by the "European Working Party on SLE", a working group created in 1990 in order to promote research in Europe on the different problems related to this disease. The "Euro-Lupus Cohort" provides an updated information on the SLE morbidity and mortality characteristics in the present decade as well as defines several clinical and immunological prognostic factors.

Lessons from the "Euro-Lupus Cohort".

The "Euro-Lupus Cohort" is composed by 1,000 patients with systemic lupus erythematosus (SLE) that have been followed prospectively since 1991. These patients have been gathered by a European consortium - the "Euro-Lupus Project Group". This consortium was originated as part of the network promoted by the "European Working Party on SLE", a working group created in 1990 in order to promote research in Europe on the different problems related to this disease. The "Euro-Lupus Cohort" provides an updated information on the SLE morbidity and mortality characteristics in the present decade as well as defines several clinical and immunological prognostic factors.