Morphometric Analysis of the Mandibular Canal and Its Anatomical Variants in a Chilean Subpopulation: Cone Beam Computed Tomography Study.

The inferior alveolar nerve (IAN), contained within the mandibular canal (MC), is a structure prone to damage in clinical and surgical procedures on the mandible. This study aimed to analyze the MC morphology and its anatomical variants in a Chilean subpopulation using cone beam computed tomography (CBCT). In total, 342 images from patients with the following parameters were observed: 120 kV, 9 mA, field of view 12 × 9 MC, and voxel size 0.12 mm. The average length of the MC recorded a mean value of 70.493 ± 4.987 mm on the right side and 70.805 ± 5.177 mm on the left side. The location of the mental foramen (MF) was most frequently found between the mandibular first and second premolar. The greatest bone thickness was found at the level of the basilar border of the 2MPM. The root closest to the MC was distal from the mandibular second molar. The lowest thickness was in the lingual area at 1MM. The prevalence of the anterior loop (AL) (61.5%) and the retromolar canal (RC) (17.5%) showed no significant differences between men and women. The results obtained showed that the morphology of the MC in the Chilean subpopulation can vary.

Root Canal Disinfection in Permanent Molars with Apical Lesion by Antimicrobial Photodynamic Therapy: Protocol for a Blind Randomized Clinical Trial.

Objective: The proposed study aims to compare the effectiveness of conventional endodontic treatment (ET) with that of ET associated with antimicrobial photodynamic therapy (aPDT) in patients with apical lesion. Methods: Controlled, double-blind, randomized clinical trial (RCT); superiority study with three parallel arms. Randomization will be conducted in exchange blocks of six, with allocation 1:1:1. The control group will receive conventional ET, while experimental group 1 (EG1) will receive conventional ET + aPDT with laser at 660 nm, fluence of 600 J/cm2; EG2 will receive conventional ET + aPDT with laser at 660 nm, fluence of 1200 J/cm2. The primary outcome will be canal disinfection before treatment, measured by analysis of colony formation (CFU/mL) and the success rate measured after 6 months on the clinical and radiographic evaluations. The mean and standard deviation will be calculated for continuous outcomes, and the CFU/mL mean between groups will be evaluated by ANOVA test. The Chi-squared test will be calculated for binary outcomes. A logistic regression analysis will be performed to assess differences in the success rate between groups, adjusted for the covariates. The Stata 18 software will be used, with a significance threshold of 5%. Conclusions: Few RCTs have evaluated the effectiveness of aPDT in root canal disinfection in patients with permanent dentition presenting apical lesion. New RCTs with larger numbers of participants are needed to support using aPDT as an adjuvant to conventional ET in root canal disinfection for routine use in clinical practice. The trial was registered prospectively in ClinicalTrials.gov (NCT05916859).

Endodoncia guiada Para el manejo de Canales Obliterados, Reporte de Caso / Guided Endodontic Treatment for the Management of Obliterated Pulp Canals. A Case Report

RESUMEN: El objetivo: de este reporte es presentar el tratamiento endodóntico de un diente ante-rior con obliteración del canal radicular, con la ayuda de la endodoncia guiada. Paciente masculino sin antecedentes médicos relevante, y en tratamiento ortodóntico. Diente 2.1 con historia de traumatismo dento-alveaolar y presencia de dolor a la percusión. En la TCHC se observa obliteración total del canal radicular en el tercio cervical y medio y un área de radiolucidez apical. Diagnóstico: Periodontitis apical Sintomática. Tratamiento: Terapia de canal No vital, con planificación virtual y guía endodóntica. Se utilizó el programa de acceso gratuito, Bluesky Plan®, para la planifica-ción digital de la guía endodóntica. El tratamiento se realizó en dos citas. Conclusión: el uso de tecnología para la resolución de casos de alta complejidad en endodoncia, podría ayudar a mejorar el pronóstico de estos dientes y ser una alternativa más segura para reducir la posibilidad de perforación y preservar estructura dental.

ABSTRACT: The aim: of this case report is to present the endodontic treatment of an anterior tooth with an obliterated pulp canal, with the help of guided endodontics. Male patient with no relevant medical history, currently with orthodontic treatment. Tooth 2.1 had a history of dental trauma and presented tenderness to percussion. The CBCT exam showed a completely obliterated root canal in the cervical and middle third, and apical radiolucency. Diagnosis: Symptomatic Apical Periodontitis. Treatment: Root canal treatment with virtual planning and endodontic guide. Bluesky Plan® free access program was used for the digital planning of the endodontic guide. The treatment: was made in two sessions. Conclusion: the use of technology for the resolution of high complexity cases in endodontics could help improve the prognosis of these teeth and be a safer alternative to reduce the possibility of perforation and preserve more tooth structure.

Fenestration and dehiscence frequency in maxillary teeth with apical periodontitis: a CBCT study / Frecuencia de dehiscencias y fenestraciones en dientes maxilares con periodontitis apical: un estudio con TCHC

ABSTRACT Introduction: to determine the frequency of fenestration and dehiscence bone defects present in maxillary teeth with apical periodontitis, mainly in teeth with endodontic treatment, as they are frequently cause of nonspecific symptoms after treatment. Methods: 1201 Maxillary Cone Beam Computed Tomography (CBCT) exams were analyzed and 803 teeth with apical periodontitis were selected. Results: of the teeth with apical periodontitis, 142 had a fenestration defect (18%) of which 105 teeth (74%) were endodontically treated. The highest frequency was observed in premolars, with no statistical differences between groups. Dehiscence defect was found in 139 teeth (17%) out of which 90 (65%) were endodontically treated. The highest frequency was observed in molars, with statistical differences in relation to other tooth types (p< 0.001). Conclusion: an important number of teeth with apical periodontitis present dehiscence or fenestration bone defects, especially in teeth with root canal treatment.

Resumen Introducción: determinar la frecuencia de fenestraciones y dehiscencias presentes en dientes maxilares con periodontitis apical, principalmente en dientes con tratamiento de endodoncia, pues frecuentemente son causa de síntomas inespecíficos después del tratamiento. Métodos: se examinaron y analizaron 1201 tomografías computarizadas de haz cónico (TCHC), y se seleccionaron 803 dientes con periodontitis apical. Resultados: de los dientes con periodontitis apical, 142 presentaban fenestración (18%), de los cuales, 105 dientes (74%) estaban tratados endodónticamente. La mayor frecuencia fue observada en premolares, sin diferencias estadísticas entre los grupos. La dehiscencia fue encontrada en 139 dientes (17%), de los cuales 90 (65%) estaban tratados endodónticamente. La mayor frecuencia fue encontrada en molares con diferencia estadísticas en relación con los otros tipos de dientes (p<0,001). Conclusión: un importante número de dientes con periodontitis apical presentan fenestraciones y dehiscencias, especialmente en dientes con tratamiento de canales radiculares.

Evaluation of apical debris extrusion and patency file in continuous and reciprocating rotary endodontic systems / Evaluación de la extrusión de residuos apicales y permeabilidad apical en sistemas endodónticos rotativos continuos y recíprocos

The aim of the study was to quantify and compare apical debris extrusion in two systems of continuous and reciprocating rotary instrumentation with, and without, the use of a patency file. An experimental study was carried out in 120 mesial roots of lower first molars, which were randomized in the following 4 groups: Group A. Reciproc (VDW) R25 without a patency file, Group B Mtwo (VDW) without a patency file, Group C Reciproc (VDW) R25 with a patency file and Group D Mtwo with a patency file. Groups A, B and C presented statistically significant differences in comparison to group D, Mtwo with the use of a patency file (p<0.008 to 95% reliability). In conclusion, the greater amount of debris extruded through the apex occurred in roots instrumented with the reciprocating rotary system; this difference was statistically significant in relation to teeth treated with the Mtwo continuous rotary system with the use of a patency file.

El objetivo del estudio fue cuantificar y comparar la extrusión de residuos apicales en dos sistemas de instrumentación endodónticos rotativos, continuo y recíproco, con y sin el uso de una lima de pasaje apical. Se realizó un estudio experimental en 120 raíces mesiales de primeros molares inferiores, que se aleatorizaron en los siguientes 4 grupos: Grupo A. Reciproc (VDW) R25 sin lima de pasaje apical, Grupo B Mtwo (VDW) sin lima de pasaje apical, Grupo C Reciproc (VDW) R25 con lima de pasaje apical y Grupo D Mtwo con lima de pasaje apical. Los grupos A, B y C presentaron diferencias estadísticamente significativas encomparación con el grupo D, Mtwo con el uso de una lima de pasaje apical (p<0.008 a 95% de confiabilidad). En conclusión, la mayor cantidad de residuos extruidos a través del ápice ocurrió en raíces preparadas con el sistema rotativo recíproco; Esta diferencia fue estadísticamente significativa en relación a los dientes tratados con el sistema rotativo continuo Mtwo con el uso de una lima de pasaje apical.

Tratamiento multidisciplinario de diente con pronóstico desfavorable. Reporte de caso / Multidisciplinary tooth treatment with unfavorable prognosis. Case report

RESUMEN: Las perforaciones radiculares son uno de los accidentes que pueden ocurrir dentro del tratamiento endodóntico rehabilitador de un diente y comprometen el pronóstico de éste. El objetivo de este reporte es describir el tratamiento y seguimiento de un diente con pronóstico desfavorable, con falsa vía y perforación en el 1/3 medio radicular. El manejo de la perforación se realizó con BiodentineTM y la rehabilitación con prótesis fija unitaria con poste de fibra individualizado. A los controles clínicos y radiográficos de 6, 12 y 24 meses el tratamiento se encontró asintomático y en función, pudiéndose considerar exitoso.

ABSTRACT: A radicular perforation is a mishap that can occur during the Endodontic and Restorative Treatment of a tooth and it can compromise its short and long-term prognosis. The aim of this report is to describe the treatment and follow up of a tooth with an unfavorable prognosis that had a perforation in the radicular middle third. The perforation was repaired with BiodentineTM and a fiber post and crown were placed. The patient had a follow up at 6, 12 and 24 months and the tooth was found asymptomatic and functional, which can be considered a clinical success.

Irrigation trends among members of the Chilean Endodontic Society

Introduction: the aim of this study is to determine the current trends of irrigation during root canal therapy by specialists who are members of the Chilean Endodontic Society. materials and method: a survey (survey monkey -SurveyMonkey.com) was e-mailed to the 485 members of the Chilean Endodontic Society. the instrument was translated and adapted from the survey "irrigation trends among American Association of Endodontists members: a web-based survey" applied in the USA in 2012. participants answered a set of 16 questions that included irrigant selection, irrigant concentration, the adopted protocol, techniques or devices for irrigant activation. results: 99 percent of respondents use sodium hypochlorite as the main irrigant. data indicate that 74 percent of respondents use hypochlorite at a concentration of 5 percent. most respondents (94 percent) also include EDTA in their usual practice. In addition, 90 percent of respondents reported that they activate the irrigating agent, and 94 percent confirmed that they perform a final irrigation protocol. conclusion: the majority of respondents use sodium hypochlorite as the main irrigant at a concentration of 5 percent, use ethylenediaminetetraacetic acid (EDTA) as a smear removal agent, activate the irrigant, and perform a final irrigation protocol.

Morphology of the physiological apical foramen of maxillary premolars / Morfología del foramen apical de premolares maxilares

SUMMARY: The purpose of this study was to determine the shape and diameter of the physiological foramen in maxillary premolars of a Chilean population. The sample consisted of 125 extracted maxillary premolars, in which the apical three to five millimeters were cut and observed under magnification of 40x, photographed (Motic Cam), and analyzed using Motic Images Plus 2.0 ML in order to obtain measurements of the minor and major diameter of each physiological foramen. The average minor and major diameter in maxillary premolars was 0.270 and 0.413 mm, respectively. In terms of shape, 72.19 % had oval shaped physiological foramen; 18.93 % were irregularly shaped and 8.88 % were round. Oval and irregular canals are significantly more difficult to shape and require special attention in order to obtain a thoroughly disinfected root canal system.

RESUMEN: El objetivo del estudio fue determinar la forma y el diámetro del foramen fisiológico de premolares maxilares en una población Chilena. La muestra consistió en 125 premolares maxilares extraídos, a los que se cortó de 3 a 5 milímetros apicales, fueron observados bajo magnificación de 40x, fotografiado (Motic Cam) y analizados utilizando Motic Images Plus 2.0 ML para obtener las mediciones de el diámetro menor y mayor de cada foramen fisiológico. El promedio del diámetro menor y mayor en premolares maxilares fue de 0,270 y 0,413 mm respectivamente. En cuanto a la forma 72,19 % tenía el foramen fisiológico de forma oval; 18,93 % tenía forma irregular y 8,88 % fue redondo. Canales ovales e irregulares son significativamente más difíciles de conformar y requieren especial atención para obtener una adecuada desinfección del sistema de canales radiculares.

Impact of traumatic dental injuries on quality of life in preschoolers and schoolchildren: A systematic review and meta-analysis.

OBJECTIVES: Traumatic dental injuries (TDIs) in childhood and adolescence are a potential public health problem given their prevalence and consequences. The aim of this study was to assess the impact of TDIs on the oral health-related quality of life (OHRQoL) of preschoolers and schoolchildren, by synthesizing the available evidence. METHODS: A systematic search was conducted in MEDLINE, EMBASE, Cochrane, ScieLo and Lilacs databases since January 1966 until March 2016. The included studies compared OHRQoL between groups with and without TDIs, using validated instruments. The selection process and data extraction were carried out by two researchers independently. A third reviewer resolved discrepancies. Methodological quality was assessed with the Effective Public Health Practice Project's Quality Assessment Tool. Meta-analyses were performed using random effect models, separately for preschoolers and schoolchildren. RESULTS: Of 213 identified articles, 26 studies (involving a total of 4582 patients and 13 601 controls between the ages of 1 and 15 years) met the inclusion criteria. Most of the studies had been published in the last 5 years, and their methodological quality was judged to be moderate. The TDIs group had a significantly higher chance of reporting any impact on OHRQoL than controls for both preschoolers (OR = 1.44; 95% confidence interval [CI]: 1.28-1.63; I2 = 0%) and schoolchildren (OR = 1.31; 95% CI: 1.04-1.66; I2 = 70%). In preschoolers, the OR for OHRQoL impact for complicated vs uncomplicated TDIs was 1.53 (95% CI: 1.04-2.26; I2 = 0%). The social domain was the most affected one in schoolchildren (standard mean difference = 0.34; 95% CI: 0.13, 0.55; I2 = 68%). CONCLUSION: Traumatic dental injuries have a negative impact on OHRQoL of both preschoolers and schoolchildren. Outcome standardization to measure OHRQoL impact, such as mean score differences and cut-off points, is needed. Prospective cohort studies are recommended to confirm these findings and to understand how TDIs' impact changes with time.

Success Rate of Autotransplantation of Teeth With an Open Apex: Systematic Review and Meta-Analysis.

PURPOSE: The aim of the present study was to determine the success rate of autotransplanted permanent teeth with an open apex and to identify the most influential prognostic factors. MATERIALS AND METHODS: A systematic search of the MEDLINE, EMBASE, LILACS, and SciELO databases was conducted for January 1990 to August 2015. The study eligibility criteria were primary studies that had evaluated patients with autotransplantation with an open apex, with or without preparation of the socket, and a minimum of 12 months of follow-up. The principal outcome was the success rate of autotransplanted teeth with an open apex. Two of us independently performed the selection process and data extraction. The Effective Public Health Practice Project's Quality Assessment Tool was used for the quality assessment of the studies. The odds ratio (OR) was calculated, with the 95% confidence interval (CI). RESULTS: A total of 21 studies were included in the present analysis. Of the 21 studies, 10 were retrospective and 11 were prospective. All the studies were of weak methodologic quality. The overall success rate was 89.68%, the survival rate was 98.21%, and the mean follow-up period was 6 years, 3 months (standard deviation 5.81 years). Among the prognostic factors analyzed, the premolars had a lower failure risk than did the molars (OR, 0.46; 95% CI, 0.25 to 0.84). The stage of development of the root and the autotransplantation receptor site showed no statistically significant differences. CONCLUSIONS: The overall success rate and survival were high, despite the methodologic limitations of the included studies. Further study is needed of the prognostic factors that influence the success of autotransplantation with an open apex.

Evaluación del tratamiento endodóntico y su relación con el tipo y la calidad de la restauración definitiva / Evaluation of edodontic treatment and its relationship with the type and quality of the definitive restoration

Introducción El éxito endodóntico está determinado por la calidad de los tratamientos de canales radiculares y restaurador, en conjunto con la ausencia de signos y síntomas. Objetivo Determinar el porcentaje de éxito de tratamientos de conductos y su relación con el tipo y la calidad de la restauración coronaria. Material y métodos Se realizó un estudio clínico retrospectivo en donde se evaluaron 227 dientes sometidos a tratamiento de canales radiculares con 4 años de evolución, por un dentista contralor, que realizó el examen clínico y radiográfico de estos dientes, evaluando los signos y síntomas que presentaron y el tipo y la calidad del tratamiento restaurador. Los datos se analizaron mediante el programa estadístico STATA 13. Resultados En los tratamientos evaluados existe un porcentaje de éxito del 93,8% y un 6,2% de fracaso, además de una asociación significativa en cuanto a que los dientes con una restauración coronaria adecuada, directa o indirecta, están relacionados con tratamientos considerados como exitosos, mediante test de Fisher (valor p < 0,01) con un nivel de confianza del 95%. Conclusiones Los resultados obtenidos en este estudio muestran un alto porcentaje de éxito de los dientes tratados endodónticamente (93,8%) y que existe una asociación estadísticamente significativa entre la calidad de la obturación y la sintomatología (p < 0,01) con un nivel de confianza del 95%.

Introduction Success in endodontic treatment is determined by the quality of the root canal treatment and definitive coronal restoration, with the absence of signs and symptoms. Objective The aim of this study was to determine the success rate of root canal treatment and its relationship with the type and quality of the coronary restoration. Material and methods A retrospective clinical study was conducted on 227 endodontically treated teeth over a period of 4 years. The analysis was performed by a comptroller dentist, who carried out the clinical and radiographical examination, evaluating signs and symptoms and the type and quality of the coronary restoration. The data analysis was performed using the STATA 13 statistics program. Results The results obtained show that there is a success rate of 93.8% and a 6.2% failure rate of the teeth evaluated. There was also significant evidence as regards teeth with proper restorations, whether direct or indirect, and root canal treatments considered as successful, according to Fisher's Test (P<.01), with a confidence level of 95%. Conclusions It can be concluded with the results obtained, that there is a high success rate (93.8%), and that there is a statistically significant association between the quality of the restoration and the presence of symptoms.

Eficiencia de tres técnicas en la remoción de gutapercha / Efficiency of three different techniques in the removal of gutta-percha

Cuando la terapia endodóntica fracasa, las opciones para solucionar este problema incluyen preservar el diente a través del retratamiento ortógrado o cirugía apical. Siempre que sea posible, el retratamiento endodóntico no quirúrgico debe ser la opción elegida. Diferentes sistemas rotatorios han sido propuestos como una alternativa a la instrumentación manual para la remoción de la gutapercha.El objetivo de este trabajo fue comparar la eficacia y la eficiencia en la desobturación total del canal radicular, utilizando dos tipos de instrumentos rotatorios: limas Protaper Universal® y limas Protaper Retratamiento® con limas manuales tipo K. Se instrumentaron 45 canales radiculares, con limas mecanizadas del sistema Mtwo®, hasta la 25/06 y terminados de conformar con lima K #40 e irrigados con hipoclorito de sodio al 2,5 % entre cada instrumento. Los dientes fueron obturados con técnica de condensación lateral, utilizando conos de gutapercha y cemento Tubliseal®.La muestra se dividió al azar en tres grupos A, B y C, de 15 canales cada uno, el grupo A se desobturó con limas Protaper Universal. El grupo B se desobturó con limas Protaper retratamiento y el grupo C se desobturó totalmente con limas K. Se cronometró cada procedimiento de desobturación y al término de esta, se tomó una radiografía en sentido buco-lingual y otra en sentido mesio-distal para cuantificar la remoción de gutapercha en cada grupo. Los resultados muestran que no existe diferencia significativa en la eliminación total del relleno endodóntico entre los tres grupos (p= 0,271) pero que los tiempos empleados en la desobturación total de los canales entre los grupos, muestra diferencias significativas entre Protaper Retratamiento y limas K, y entre Protaper Universal y limas K (p <0,05). Bajo las condiciones de este estudio, ningún sistema fue capaz de remover toda la gutapercha del interior del canal radicular.

When primary endodontic treatment fails, the treatment alternatives for root preservation are orthograde retreatment or apical surgery. Whenever possible, orthograde retreatment must be the first option. Different rotary systems have been proposed as an alternative to manual instrumentation for the removal of gutta-percha. The aim of this study was to compare the efficacy and efficiency of the total removal of gutta-percha from root canals, using two types of rotary instruments: Protaper Universal Files® and Protaper Retreatment Files®, compared to manual K type Files. A total of forty-five canals were instrumented with Mtwo files® up to a 25.06 file and the shaping was completed with a 40 K-type File and irrigated with 2.5 % Sodium Hypochlorite between each instrument. The teeth were obturated with Lateral Condensation Technique, using gutta-percha and Tubliseal® sealer. Samples were divided in groups A, B and C, 15 canals each, and gutta-percha was removed using the following protocols: group A with Protaper Universal; Group B using Protaper Retreatment and Group C using K type Files. Each procedure was timed and at the end of it, two periapical radiographs were taken: one buccolingual and one mesiodistal, in order to quantify the amount of gutta-percha removed. The results analysis show that there is no significant difference in the amount of gutta-percha removed between the three groups (p= 0.271) but that the time invested to perform the removal of the gutta-percha was significantly less between for the rotary systems, when compared to manual instrumentation (p <0.05). Under the conditions of this study, no system was able to remove all gutta percha inside the root canal.

Increase in sunburns and photosensitivity disorders at the edge of the Antarctic ozone hole, southern Chile, 1986-2000.

BACKGROUND: Over the past 15 years Punta Arenas, Chile, a medium-sized city located on the extreme southern tip of South America, has repeatedly been exposed to acute, sudden episodes of highly increased levels of ultraviolet B (UVB) 280-320 nm radiation because of the passage of the spring Antarctic "Ozone Hole" overhead, or nearby. OBJECTIVE: Our purpose was to observe the relationship between episodes of ozone depletion, increased UVB radiation, and sunburns and photosensitivity disorders in Punta Arenas, Chile, during spring. METHODS: Incidence of photosensitivity disorders and sunburns was registered by dermatologists during each of the past 15 springs. Local data of sudden, severe ozone depletions (<250 Dobson units) and the corresponding increase of UVB radiation were reviewed. RESULTS: Patients with sunburn increased significantly during the austral spring of 1999 (P <.01). This was especially noticeable (29/31 cases) on weekends with ozone depletion, and increased UVB radiation (P <.01) occurred on the Sundays Oct 31, Nov 21, and Dec 5, 1999. The incidence of photosensitivity disorders, although statistically not significant, increased 51% over the past 7 years. CONCLUSIONS: An acute impact on human health (sunburn) occurred because of abrupt ozone depletion and the accompanying increase in UVB during the mid and late austral spring of 1999. Most sunburns (93.5%) occurred on weekends. Ozone levels as well as seasonal and recreational factors played a mayor role in the increase in sunburns. The increase in radiation at 300 nm, the most carcinogenic wavelength, on days under the Antarctic ozone hole is a matter of special concern.

Skin cancer and ultraviolet-B radiation under the Antarctic ozone hole: southern Chile, 1987-2000.

BACKGROUND: Punta Arenas, Chile, the southernmost city in the world (53 degrees S), with a population of 154,000, is located near the Antarctic ozone hole (AOH) and has been regularly affected by high levels of ultraviolet-B (UV-B) radiation each spring for the last 20 years. Large increases in UV-B associated with the AOH have been measured with increases in UV-B at 297 nm of up to 38 times those of similar days with normal ozone. Recently we reported significant increases in sunburns during the spring of 1999 on days with low ozone because of the AOH. METHODS: A surveillance of skin cancers occurring from 1987 to 2000 was performed. Age, sex, location, type of skin cancer and skin phototype were recorded. A Brewer Spectrophotometer was used in order to obtain in situ measurements of ozone and UV-B. Total Ozone Mapping Spectrometer (TOMS) data from National Aeronautics and Space Administration (NASA) was used in order to establish pre-ozone hole climatology. RESULTS: Ozone levels as low as 145 DU (Dobson Units) were recorded, a 56% decrease in ozone, and UV-B levels up to 4.947 J/m2. These levels are close to summertime levels at mid latitudes. For the 14-year period--from 1987 to 2000--173 cases of skin cancer were diagnosed, 65 during the first 7 years, 108 during the second, an increase of 66%. Cutaneous malignant melanoma (CMM), 19% of the cases, increased by 56%, raising the rate from 1.22 to 1.91 per 100,000. Non-melanoma skin cancer (NMSC), 81% of the total, increased the rate from 5.43 to 7.94 per 100 000 (P < 0.05), a 46% increase. Patients with CMM and NMSC had skin phototypes I-II in 59% and 54% of cases, respectively. Days with more than 25% ozone loss occurred in 143 days during the last 20 springs. Significant increases of UV-B were observed under ozone hole conditions, especially around 300 nm, the most carcinogenic wavelengths. CONCLUSIONS: Highly unusual ozone loss and UV-B increases have occurred in the Punta Arenas area over the past two decades resulting in the non-photoadapted population being repeatedly exposed to an altered solar UV spectrum with a greater effectiveness for erythema and photocarcinogenesis. This phenomenon has not previously been reported over other populated areas and an additional increase in the skin cancer rate attributable to the AOH may be occurring. Research on the clinical and subclinical impact of these abnormalities is urgently needed.

Síndrome de Waardenburg tipo II: a propósito de dos casos clínicos / Waardenburg's syndrome type II: a propose of 2 clinical cases

El Síndrome de Waardenburg representa la forma más común de sordera congénita; es una condición pleitrópica, autosómica dominante, con penetrancia y expresividad variable. Se describen dos casos clínicos de Síndrome de Waardenburg tipo II. Las principales manifestaciones son la sordera sensorioneural congénita, alteraciones de la pigmentación pilosa y cutánea, puente nasal ancho, hipertricosis de las cejas, mandíbula cuadrada, encanecimiento prematuro y alteraciones neurológicas. Se revisan los criterios de diagnóstico de la enfermedad y los hallazgos asociados descritos de la literatura