Effect of tooth-bleaching on the carbonate concentration in dental enamel by Raman spectroscopy

There are not many studies evaluating the effects of surface treatments at the molecular level. The aim of this in vitro study was to analyze the concentration of carbonate molecules in dental enamel by Raman spectroscopy after the application of in-office and home whitening agents. Sixty human teeth were randomly divided into six groups and exposed to three different home bleaching gels (Day White) and three in-office whitening agents (Zoom! Whitespeed and PolaOffice) according to the manufacturer´s instructions. The concentration of carbonate molecules in enamel was measured prior to and during the treatment by means of Raman spectroscopy. Statistical analysis included repeated measures analysis of variance (p≤0.05) and Bonferroni pairwise comparisons. At home bleaching agents depicted a decrease in the carbonate molecule. This decrease was statistically significant for the bleaching gel with the highest hydrogen peroxide concentration (p≤0,05). In-office whitening agents caused an increase in carbonate, which was significant for all three groups (p≤0,05). In-office bleaching gels seem to cause a gain in carbonate of the enamel structure, whilst at-home whitening gels caused a loss in carbonate

Effect of Preseating on the Extrusion of Excess Cement at the Crown- Abutment Margin and the Associated Tensile Force for Cement-Retained Implant Restorations. A Pilot Study

The purpose of this study was to compare the effect of preseating prior to cementation on the amount of cement excess at the crown-abutment margin and to analyze the associated tensile force after cementation. Preseating of the crown on an abutment analog was evaluated. Ten implant copings were cemented with temporary cement on ten straight implant abutments. The amount of cement excess at the crown margins was measured by weight. Axial tensile force was measured 24 hours after the cementation. Results were statistically analyzed using ANOVA (p= 0.05). Preseating of the crown had a significant effect on the amount of cement excess at the crown margin (p<0.05), without lowering the tensile strength values significantly. When cementing crowns on implant abutments with temporary cement a preseating protocol might be advisable in order to reduce the amount of cement excess at the crown margin

Validación de un instrumento para conocer el nivel de satisfacción de pacientes rehabilitados con prótesis removible

The survey is an element of health data collection. The validity of the questionnaire is essential to achieve useful evidence, being a crucial aspect in identifying and correcting sources of bias during data collection. Verbal and cognitive tests are recognized as a tool to assess whether questions cause problems for both, the interviewer and the interviewee. The aim of this study was to validate the OHIP-49 and OHIP-19 instruments in a sample of Costa Ricans applying cognitive tests such as probing and thinkalouds and then a standard pretest. In a sample of 15 individuals rehabilitated with dentures a questionnaire of 42 items was applied that served as a cognitive test. Also 20 individuals performed a standard pretest using the telephone. The validation of this instrument served to determine the final sample for a further investigation and also to collect information about the duration of the survey as well as its comprehension.La encuesta es un elemento básico de recopilación de datos en salud. La validez del cuestionarioes esencial para lograr pruebas útiles, siendo un aspecto crucial en la identificación y la correcciónde fuentes de sesgos en los mismos. Las pruebas verbales se han reconocido como herramienta paraevaluar si las preguntas causan o tienen algún problema, tanto para el entrevistador como para elentrevistado. El objetivo de este estudio fue validar el formulario OHIP-49 y OHIP-19 en una poblaciónde costarricenses mediante la aplicación de pruebas cognitivas para cuestionarios como la pruebaverbal y posteriormente un pretest estándar. En una muestra de 15 individuos rehabilitados con prótesisremovibles se aplicó un cuestionario de 42 preguntas con pruebas cognitivas de manera personal y a 10individuos se les aplicó un pretest estándar por vía telefónica. Con las pruebas se validó el instrumento,se conoció el tiempo necesario para aplicar el instrumento vía telefónica y a seleccionar una muestraestadísticamente significativa.

Effect of Preseating, Screw Access Opening, and Vent Holes on Extrusion of Excess Cement at the Crown-Abutment Margin and Associated Tensile Force for Cement-Retained Implant Restorations

PURPOSE: This study sought to (1) compare the effects of crown preseating prior to cementation, (2) determine whether maintenance of screw access openings on titanium abutments and open vent holes on cast crowns affects the amount of excess cement at the crown-abutment margin, and (3) analyze the associated tensile force after cementation. MATERIALS AND METHODS: Three independent variables were tested: (1) abutment screw access (open or closed), (2) crown coping modification (with or without a vent hole in the palatal aspect), and (3) crown preseating on an abutment analog. Ten implant crown copings were cemented using temporary cement on ten straight implant abutments for each combination of the three independent variables. The amount of excess cement at the crown margins was measured by weight. Axial tensile load was measured 24 hours after cementation. Results were statistically analyzed using linear regression and univariate three-way analysis of variance (α = .05). RESULTS: Open screw access, presence of a vent hole on the crown, and preseating of the crown had significant effects on the amount of excess cement at the crown margin (P < .05). Preseating significantly lowered tensile strength values (P = .001), particularly in specimens with preseating and open screw access (P < .001). There was no significant correlation between excess cement at the margins and tensile strength values. CONCLUSION: Placement of vent holes on the crown or open screw access may be considered for cementing crowns on implant abutments using temporary cement in order to minimize excess cement at the crown margin. A preseating protocol is not advisable, either alone or combined with open screw access, since it significantly reduces the retentive strength of cemented restorations (P < .001).UCR::Vicerrectoría de Docencia::Salud::Facultad de Odontologí

Effect of tooth-bleaching on the carbonate concentration in dental enamel by Raman spectroscopy

BACKGROUND: There are not many studies evaluating the effects of surface treatments at the molecular level. The aim of this in vitro study was to analyze the concentration of carbonate molecules in dental enamel by Raman spectroscopy after the application of in-office and home whitening agents. MATERIAL AND METHODS: Sixty human teeth were randomly divided into six groups and exposed to three different home bleaching gels (Day White) and three in-office whitening agents (Zoom! Whitespeed and PolaOffice) according to the manufacturer´s instructions. The concentration of carbonate molecules in enamel was measured prior to and during the treatment by means of Raman spectroscopy. Statistical analysis included repeated measures analysis of variance (p≤0.05) and Bonferroni pairwise comparisons. RESULTS: At home bleaching agents depicted a decrease in the carbonate molecule. This decrease was statistically significant for the bleaching gel with the highest hydrogen peroxide concentration (p≤0,05). In-office whitening agents caused an increase in carbonate, which was significant for all three groups (p≤0,05). CONCLUSIONS: In-office bleaching gels seem to cause a gain in carbonate of the enamel structure, whilst at-home whitening gels caused a loss in carbonate.Universidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Docencia::Salud::Facultad de Odontologí

Success Assesment of Patients Rehabilitated with Removable Prosthesis

El objetivo de este estudio es determinar el nivel de satisfacción del paciente rehabilitado con prótesis removibles en el grado de Odontología General, desde el año 2011 al 2013, usando el instrumento OHIP-49, OHIP-19 EDENT y criterios de la OMS para encuestas de salud bucodental. Materiales y Métodos: se aplicó el instrumento previamente validado, con preguntas cerradas vía telefónica a una muestra de 152 pacientes de la Universidad de Costa Rica. Se realizaron coeficientes de correlación y regresión logística para análisis de datos, con el fin de correlacionar características socio-demográficas con niveles de satisfacción generales y específicos. Resultados: la satisfacción general en una escala del 1 al 10 fue de 9.3 y la satisfacción medida en factores específicos fue de 8.54. Los factores como la masticación y el uso diario sin presencia de dolor fueron las menos satisfactorias. La prótesis removibles inferiores fueron las menos satisfactorias en factores como masticación y uso libre de dolor. Al aplicar el coeficiente de correlación, se encuentra una relación alta y positiva con respecto a la masticación. Con la regresión logística se encuentra que los pacientes mayores de 56 años, que no realizan actividad física y que ingieren alcohol, tienen mayor posibilidad de generar niveles de satisfacción bajos. Conclusiones: el porcentaje de satisfacción general de los pacientes rehabilitados con prótesis removibles fue superior al 85%. Las cualidades menos satisfactorias fueron la masticación y el uso diario sin presencia de dolor.The aim of this study is to determine the level of patient satisfaction with dentures rehabilitated a the School of Dentistry, from 2011 to 2013, using the OHIP-49 instrument, OHIP-19 edent and WHO criteria for oral health surveys. Materials and Methods: A previously validated survey instrument was applied by telephone to a sample of 152 patients from the University of Costa Rica. Correlation coefficients and logistic regression were carried out in order to correlate socio-demographic characteristics with general and specific satisfaction levels. Results: the general satisfaction generated by the patient on a scale of 1 to 10 was 9.3. Satisfaction derived from specific categories was 8.54, with factors such as mastication and daily use without pain being the less satisfactory. The lower dentures were the least accepted in factors such as mastication and free use of pain. By applying the correlation coefficient, high and positive relationship was found related to mastication. Logistic regression found that patients older than 56, who do not exercise and drink alcohol, are more likely to generate lower levels of satisfaction. Conclusions: The percentage of overall satisfaction of patients rehabilitated with dentures was above 85%. Less satisfactory qualities were mastication and daily use without the presence of pain.UCR::Vicerrectoría de Docencia::Salud::Facultad de Odontologí

Titanium dioxide in dental enamel as a trace element and its variation with bleaching

BACKGROUND: Titanium is a less studied trace element in dental enamel. Literature relates an increased Titanium concentration with a decreased enamel crystal domain size, which in turn is related to a higher color value. The aim of our study was to analyze the effect of tooth bleaching agents on its concentration in dental enamel by means of confocal Raman spectroscopy. MATERIAL AND METHODS: Human teeth were randomly distributed in six experimental groups (n=10) and submitted to different bleaching protocols according to the manufacturer´s instructions. Confocal Raman spectroscopy was carried out in order to identify and quantify the presence of titanium dioxide molecules in enamel prior to and during whitening. Statistical analysis included repeated measures analysis of variance (p≤0.05) and Bonferroni pairwise comparisons. RESULTS: Titanium dioxide concentration was negatively affected by the longer bleaching protocols (at-home bleaching gels). All in-office whitening products increased significantly the studied molecule (p≤0,05). CONCLUSIONS: All dental specimens depicted the presence of titanium dioxide as a trace element in dental enamel. Bleaching gels that have to be applied at higher concentrations but for shorter periods of time increase the concentration of titanium dioxide, whilst at-home whitening gels used for longer periods of time despite the lower concentration caused a loss in titanium.Universidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Docencia::Salud::Facultad de Odontologí

Resistance to dynamic and static loading of the implant mounts on its respective implant

Introduction: Implant restorations should endure a variable range of forces over a long period of time. Some commercial brands offer the implant together with an accessory called “implant mount” or “implant holder,” which might be used as a temporary abutment. However, scientific literature in the use of implant holders as abutments for restorations is scarce. Objectives: The purpose of this in vitro study was to compare the load at which implant holders of Implant Direct® and Zimmer® fail under static compression after being subjected to fatigue, and to compare the gap produced between the implant–holder complexes after dynamic loading. Materials and Methods: The test protocol was based on the recommendation of ISO 14801. Five implant–implant holder assemblies of each brand were subjected to dynamic loading. A load of 250 N was applied at 5 × 106 cycles and at 15 Hz stress frequency (Eden Prairie, MN, USA). The gap (µm) at the interface was measured postfatigue using scanning electron microscopy (S‑3700N, HITACHI, Japan), and afterward, static loading was applied and the maximum load (N) after the point of failure was established. Implant–definitive abutment complexes were used as controls. Data were analyzed by means of a central tendency measurement test Mann–Whitney U‑test (nonparametric). Results: There was no difference between both the implant holder groups (P ≤ 0.05); however, a slight trend of greater resistance was observed for the Zimmer® group. The gap in the interface was greater for Implant Direct® implants, but the difference was not statistically significant. Conclusion: No significant differences were found in terms of the maximum load under compression or the interface gap after the dynamic loading in the two experimental groups.Universidad de Costa Rica/[]/UCR/Costa RicaUCR::Vicerrectoría de Docencia::Salud::Facultad de OdontologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ingeniería::Laboratorio Nacional de Materiales y Modelos Estructurales (LanammeUCR

Effect of a preseating cementation protocol on the retention of implant restorations using a definitive cement

Purpose: This investigation analyzed the effects of a preseating cementation protocol on the amount of cement excess at the crown margin and its associated tensile load using a glass ionomer definitive cement. Materials and Methods: The independent variable in this study was the cementation technique. The first protocol involved a conventional cementation procedure and the second one preseating on an abutment replica. Ten metallic copings were cemented using a definitive cement on ten implant abutments for each cementation protocol. Cement excess at the margin was weighted (mg), and axial tensile load was measured 24 h after cementation. Results were statistically analyzed using linear regression and one-way analysis of variance (α = 0.05). Results: The cementation protocol with preseating resulted in a significantly smaller amount of cement excess at the crown margin (P ≤ 0.001) without detriment on the tensile resistance when compared to the experimental group without preseating (P = 0.41). Linear regression failed to prove any correlation between the amount of cement excess and tensile load necessary for dislodgement. Conclusions: A preseating protocol can be performed when using a definitive cement. This procedure reduces significantly the amount of cement excess at the margin while maintaining an acceptable tensile load resistance.UCR::Vicerrectoría de Docencia::Salud::Facultad de Odontologí

Análisis de la estructura cristalina del esmalte dental por medio de difracción de rayos X después del tratamiento con agentes blanqueadores a diferentes concentraciones

Seminario de graduación (licenciatura en odontología)UCR::Vicerrectoría de Docencia::Salud::Facultad de Odontologí