Descripción de la Morfología del Sistema de Canales Radiculares en Premolares Maxilares Mediante Tomografía Computarizada Cone Beam en una Población Chilena

El tratamiento endodóntico requiere detallados conocimientos sobre la morfología radicular. En premolares maxilares, se ha reportado variabilidad en el número de raíces y morfología del sistema de canales radiculares (SCR). La causa más frecuente de fracaso endodóntico son los conductos no tratados. Por lo tanto, una mejor compresión de la morfología del SCR y sus variaciones es crucial para el tratamiento endodóntico. El objetivo de esta investigación fue describir la frecuencia del número de raíces y morfología del SCR en premolares maxilares, mediante exámenes de tomografía computarizada Cone Beam (CBCT) en una población chilena. Se realizó un estudio observacional descriptivo de corte transversal donde se observó la morfología del sistema de canales radiculares de primeros y segundos premolares maxilares a través de exámenes CBCT, agrupándolos de acuerdo con la Clasificación de Vertucci. Se observaron 228 exámenes CBCT, donde se incluyeron 268 primeros premolares superiores y 233 segundos premolares maxilares. Se determinó que en primeros premolares maxilares un 56,3 % presentó una raíz, un 43,3 %, siendo más frecuente una morfología del SCR tipo IV. En los segundos premolares maxilares, se determinó la presencia de una raíz en el 95,7 % de los casos, siendo más frecuente una morfología del SCR tipo I. Estos resultados pueden ser de interés para endodoncistas, ya que conocer la morfología del SCR de premolares maxilares permite mejorar la planificación de la terapia endodóntica realizada en estos dientes.

Endodontic treatment requires detailed knowledge of root morphology. In maxillary premolars, variability in root number and root canal system (RCS) morphology has been reported. The most frequent cause of endodontic failure is non treated canals. Therefore, a better understanding of RCS morphology and its variations is crucial for endodontic treatment. The aim of this research was to describe the frequency of root number and SCR morphology in maxillary premolars, by means of Cone Beam Computed Tomography (CBCT) examinations in a Chilean population. A cross-sectional descriptive observational study was carried out in which the morphology of the root canal system of maxillary first and second premolars was observed through CBCT examinations, grouping them according to the Vertucci Classification. A total of 228 CBCT examinations were observed, which included 268 upper first premolars and 233 maxillary second premolars. It was determined that in maxillary first premolars 56.3 % presented one root, 43.3 %, being more frequent a SCR type IV morphology. In maxillary second premolars, the presence of one root was determined in 95.7 % of the cases, being more frequent a SCR type I morphology. These results may be of interest to endodontists, since knowing the morphology of the RCS of maxillary premolars allows improving the planning of endodontic therapy performed on these teeth.

Root anatomy and canal configuration of maxillary premolars: a cone-beam computed tomography study / Anatomía de la raíz y configuración del conducto de los premolares maxilares: estudio de tomografía computarizada de haz cónico

SUMMARY: The aim of the study was to determine the number and anatomical configuration of roots and root canals of maxillary first and second premolars using cone-beam computed tomography scans. n273 CBCT scans were evaluated, obtaining a sample of 592 maxillary premolars. Root number and root canal anatomy were categorized using Ahmed´s classification. Data was analyzed using Pearson's Chi-squared test. Two roots were present on 157 first premolars, one root in 132 premolars and three roots in 17. Second premolars presented one root in 266 samples and two roots in 20; no second premolars presented three roots. Eight different configurations were found; the most frequent was 2MP B1 P1 in first premolars (51,3 %) and 1MP1 (63.6 %) in second premolars. The most frequent morphology found in maxillary premolars in Chilean population was two and three roots. The analysis of internal anatomy using CBCT revealed a highly variable distribution of root canals, generally of low to medium complexity, similar to what is found in other ethnic groups.

RESUMEN: El objetivo de este estudio fue determinar el número y la configuración de raíces y canales radiculares de primeros y segundos premolares maxilares utilizado tomografía computacional de haz cónico. 273 TCHC fueron evaluados, obtenido una muestra de 592 premolares maxilares. El número de raíces y la anatomía de los canales radiculares fueron categorizados utilizando la clasificación de Ahmed. Los datos fueron analizados con la prueba Chi- Cuadrado de Pearson. Dos raíces fueron observadas en 157 primeros presentaron una raíz en 266 muestras y dos raíces en 20; no se encontraron tres raíces en segundos premolares. Ocho diferentes configuraciones fueron encontradas; siendo la más frecuente 2MP B1 P1 en primeros premolares (51,3 %) y 1MP1 (63,6 %) en segundos premolares. La morfología radicular más frecuentemente encontrada en premolares de población Chilena fue de dos y tres raíces. El análisis de la anatomía interna usando TCHC mostró una gran variabilidad de en la distribución de los canales radiculares. Generalmente de mediana y baja complejidad como los encontrados en otros grupos etnicos.

Morphological Study and Analysis of Microhardness and Permeability of the Furcation of Maxillary Premolars

Abstract The morphology, microhardness and dentin permeability of the furcation region of maxillary premolars were evaluated. Ten premolars were cut lengthwise and the furcation region was delimited. In one group (n=10) microhardness was measured in the buccal, central and palatal regions, in the outer middle and inner layers of the furcation, and in the buccal and palatal regions adjacent to the furcation. Knoop hardness was tested with 10 g load for 15 s. Data were analyzed statistically by ANOVA and Tukey-Kramer test (a=0.05). In the other group (n=10) confocal microscopy was used to study dentin morphology. Other 10 specimens were instrumented with ProTaper and immersed in 10% copper sulfate for analysis of permeability under light microscopy. About microhardness, there was no significant difference (p>0.05) among the buccal (39.9±3.1), central (39.5±4.4) and palatal (39.7±5.0) regions of the furcation, or between these regions and the adjacent buccal (39.1±5.8) and palatal (39.7±5.8) regions (p>0.05). The inner layer (42.3±3.7) had significantly higher microhardness (p<0.05) than the outer layer (37.1±3.9). There was a tendency of calcification of the dentinal tubules from the outer towards the inner layer. The percentage of stained area was 12.45±2.0%, restricted to the outer layer. The buccal, central and palatal regions of the furcation as well as the buccal and palatal adjacent regions had similar microhardness values. In conclusion, the inner dentin layer is harder than the outer dentin layer. The dentinal tubules are sinuous and intertwine towards the middle layer. Dye penetration is restricted to the outer layer.

Resumo Estudou-se a morfologia, microdureza e permeabilidade dentinária da furca de pré-molares superiores. Dez pré-molares tiveram a porção oclusal da coroa e os terços radiculares médio e apical removidos. Cortou-se longitudinalmente o remanescente e delimitou-se a furca. As hemi-secções foram distribuídas em dois grupos. Num (n=10), mediu-se a microdureza nas regiões vestibular, central e palatina, nas camadas externa, média e interna e nas porções vestibular e palatina adjacentes à furca. Utilizou-se dureza Knoop, carga de 10 g por 15 s. Os dados foram analisados pelo teste ANOVA e Tukey-Kramer (a=0.05). No outro grupo (n=10) utilizou-se microscopia confocal para estudo da morfologia da dentina. Outros 10 espécimes foram instrumentados com Protaper e NaOCl a 1% e imersos em sulfato de cobre a 10% para análise da permeabilidade. Após preparo histológico os espécimes foram analisados em fotomicroscópio. Não houve diferença significante (p>0,05) entre a microdureza das regiões vestibular (39,9±3,1), central (39,5±4,4) e palatina (39,7±5,0), nem entre essas regiões e as adjacentes vestibular (39,1±5,8) e palatina (39,7±5,8) (p>0,05). A camada interna (42,3±3,7) é mais dura que a externa (37,1±3,9) (p<0,05). Há uma tendência dos canalículos calcificarem no sentido da camada externa para a interna. A porcentagem de área corada foi de 12,45±2.0 e restrita à camada externa. As regiões vestibular, central e palatina da furca, bem como as adjacentes vestibular e palatina apresentaram microdureza semelhante entre si. A camada interna apresentou-se mais dura que a externa. Os canalículos dentinários eram sinuosos e se entrelaçaram em direção à camada média. A penetração de corantes se restringiu à camada externa.