Is third molar agenesis an anomaly or just a sign of variation? Prevalence and manner of presentation of this condition in a sample from the Metropolitan Region of Chile / ¿Es la agenesia del tercer molar una anomalía o simplemente un signo de variación? Prevalencia y forma de presentación de esta condición en una muestra de la Región Metropolitana de Chile

Agenesis of permanent teeth is the most frequent dental anomaly. The most affected tooth is the third molar (M3), and its congenital absence poses interesting questions from a clinical and evolutionary perspective. M3 agenesis can occur isolated or as part of syndromes. Researchers have reported prevalences that vary largely among populations, between 5 % and 56 %, with a mean prevalence of 22.6 %. Previous Chilean studies, mainly in Northern populations, have determined a prevalence between 19.8 % and 26.7 %. The aim of this work was to assess the prevalence of M3 agenesis and to characterize its presentation in a sample from Santiago, the largest to date in a M3 agenesis prevalence study in Chile. In this study, 535 panoramic radiographies and clinical histories of patients from the Dental Clinic of the Universidad de Chile were used to determine prevalence and distribution according to sex, affected tooth, and location (left or right; maxilla or mandible). The Chi-square test was used to assess statistical significance in distribution. The calculated M3 agenesis prevalence was of 12.89 %. No statistically significant differences were found between sexes, sides or location within the jaws. The agenesis of one third molar was more common, then two, three and finally of all the third molars. The prevalence of M3 agenesis in the sample is 12.89 %, with a random manner of presentation. We propose that as it currently stands, M3 agenesis should be considered an anatomical variation rather than a developmental anomaly.

La agenesia de dientes definitivos es la anomalía dental más común. El diente más afectado es el tercer molar (M3), y su ausencia congénita plantea preguntas interesantes desde una perspectiva clínica y evolutiva. La agenesia de M3 puede ocurrir de manera aislada o asociada a síndromes. Estudios a nivel mundial reportan una prevalencia variable entre poblaciones: 5 % a 56 %, con una prevalencia media del 22,6 %. Estudios chilenos anteriores, principalmente en poblaciones del norte, han determinado una prevalencia entre 19,8 % y 26,7 %. El objetivo de este trabajo fue determinar la prevalencia de agenesia de M3 y caracterizar su presentación en una muestra de Santiago, la más grande hasta la fecha en un estudio de prevalencia de agenesia de M3 en Chile. Se utilizaron 535 radiografías panorámicas y antecedentes de pacientes atendidos en la Clínica Odontológica de la Universidad de Chile para evaluar la prevalencia y modo de presentación de la agenesia de M3. Se analizó su distribución según ubicación, sexo y simetría, mediante test estadístico Chi-cuadrado. Se calculó una prevalencia de agenesia de M3 de 12,89 %, sin un patrón claro ni estadísticamente significativo en su distribución. Fue más común la agenesia de un tercer molar, luego de dos, tres y finalmente de todos los terceros molares. La prevalencia de agenesia en una muestra de la Región Metropolitana es de 12,89 % y su distribución es aleatoria según la ubicación, sexo y simetría. Se propone que esta condición actualmente debiera considerarse como una variación anatómica más que a una anomalía del desarrollo.

Depresión en el adulto mayor: evaluación preliminar de la efectividad, como instrumento de tamizaje, de la versión de 5 ítems de la escala de depresión geriátrica / Preliminary report on the effectiveness of the 5-item version of the geriatric depression scale for depression screening in a Chilean community-dwelling elderly population

Introduction: The best approach to improve under-recognition of depression is routine screening, idealy using an instrument that is highly effective and easy to administer. Objective: To test the effectiveness of the 5-item version of the Geriatric Depression Scale (5-GDS) for depression screening in a community-dwelling Chilean elderly population. Participants and Methods: 110 subjects were evaluated at the geriatric outpatient clinic of a university teaching hospital. Patients answered a questionnaire that included the Geriatric Depression Scale (GDS), and demographic information. Using the 15-item GDS score as reference standard to classify subjects as depressed, test characteristics of the 5-GDS were evaluated. Results: Subjects had a mean 15-item GDS score of 5.4; 47 percent classified as depressed. Depressed and not depressed subjects were similar with regard to demographics, educational level and comorbid conditions. The mean score was 1.9 for the 5-item GDS. Pearson correlation for 15-item and 5-item GDS scores was 0.92, p<0.001. Using 15-item GDS score as reference standard, the 5-item GDS had a sensitivity of 0.88, specificity 0.90, positive predictive value 0.88 and negative predictive value 0.90. Conclusions: The 5-item GDS seems to be a promising screening tool for depression. If revalidated against clinical evaluation, it might be the preferred screening tool for depression in the Chilean community-dwelling elderly