A Cone Beam Computed Tomographic Analysis of Root and Canal Morphology of Mandibular Premolars in a Selected Kenyan Population

Abstract

Background: Successful root canal therapy requires knowledge and visualization of the detailed canal anatomy to avoid missed canals, inadequate instrumentation, and other iatrogenic errors. Traditional methods used to study root canals have their limitations in that the teeth under study may need to be destroyed and are thus not applicable in vivo. Cone beam computed tomography (CBCT) which is one of the newer methods used is quite modern and provides 3D images that allow canal anatomy to be studied in vivo without destroying the tooth. Mandibular premolars have been found to have a complex anatomy thus leading to difficulty in root canal therapy. Further, no data is available on root and root canal morphology on mandibular premolars using CBCT in Kenya hence this study. Broad objective: To analyse the root and canal morphology of mandibular premolars in a Kenyan population using CBCT imaging technique. Study design: This was a descriptive cross-sectional study. Study area: The study was carried out at Damic x-ray centre which is located in Upper Hill in Nairobi, Kenya. Study population: The study population constituted CBCT Images of patients who visited the Damic x-ray centre between Dec 2017 - February 2023. Sample size determination: Sample size determination was calculated using Fisher’s method of sample size determination and a sample size of 245 images arrived at. Materials and method: The sampling technique was convenient sampling. The external anatomy of mandibular premolars were described and analysed in terms of number of roots, root length and curvature. The internal anatomy of the mandibular premolars was evaluated

according to Vertucci1984 classification, number of canals and presence of lateral canals were determined. The collected data was entered in a coded form and analysed using SPSS (statistical package for social sciences version 25). Descriptive statistics were done for the various variables. The chi-square and fisher’s exact test were used to analyse the differences in gender variation in number of roots, root curvature, root configuration according to Vertucci and number of canals. The t-test was used to compare the mean root lengths of mandibular premolar roots according to gender. Alpha level was set at 0.05%. The results were presented in bar graphs and tables. Ethical approval was granted by the KNH-UoN Ethics and Research committee reference number (UP412/08/2020). Results: From this study the first mandibular premolars had one root in 100 (85.5%) and two roots in 17 (14.5%) images. Among the second premolars 123 (93.9%) had one root and 8 (6.1%) had two. Majority (91.9%) of the premolars had straight roots for both first and second mandibular premolars. The first premolar root length ranged between 18.70 – 26.90 mm with a mean length of 22.99 (± 1.66 SD). The second premolar root length ranged between 19.50 – 28.20 mm with a mean length of 23.10 (± 1.65 SD). Males had an average mean length of 23.5mm while females 22.6mm for first premolars. For second premolars males had an average length of 23.9mm and females 22.3mm. The difference in mean length was statistically significant with the males having longer roots (t test= 2.921, p=0.004) for first premolars and second premolars (t test 5.587, p<0.001).

Root canal configurations were identified as per Vertucci's 1984 classification. Within the first premolars, type I of the Vertucci 1984 classification was the most predominant (74.4%). Within the second premolars, type I of the Vertucci 1984 classification was the most predominant (92.4%). Conclusion: CBCT imaging technique was useful for evaluating the anatomy of mandibular premolars. Premolar lengths for men were greater than those for women. The most prevalent Vertucci configuration was type I, followed by type V in both first and second premolars.