Root Canal Morphology of 116 Maxillary Second Premolars by Micro-Computed Tomography in a Mixed Swiss-German Population with Systematic Review.

INTRODUCTION: The aim of this investigation was to examine the root canal system morphology of maxillary second premolars (Mx2Ps) of a Swiss-German population by means of micro-computed tomography and provide systematic review of the root canal configuration (RCC) literature of Mx2Ps. METHODS: The RCC, main foramina as well as accessory canals and foramina frequency of 116 Mx2Ps, were investigated by means of micro-computed tomography and 3-dimensional software imaging. The RCC from the coronal to apical thirds of the root as well as the main foramina number were described by using a four-digit system code. The literature review follows the PRISMA guideline analyzing randomized controlled trials and cross-sectional, cohort, comparative, validation, and evaluation studies on RCC in Embase, grey literature, PubMed, and Scopus. RESULTS: Most frequently observed RCCs of Mx2Ps were 1-1-1/1 (35.3%), 1-1-1/2 (21.6%), and 2-1-1/1 (14.7%). Another 11 less frequent RCCs were observed. All Mx2Ps had 1 root. One main foramen was observed in 59.5% and two in 37.9%. Accessory foramina were observed in 46.6%. Thirty-one percent of the Mx2Ps showed accessory canals. One connecting canal between the buccal and palatal was observed in 12.1%. CONCLUSIONS: Detailed RCC information of Mx2Ps in a Swiss-German population and the results of a systematic literature review of different populations and research methods used to investigate root canal morphology and configuration of Mx2Ps are given. Within the limitations of the study, a high RCC, connecting and accessory canals variability occur in maxillary second premolars.

An Ex Vivo Study of Root Canal System Configuration and Morphology of 115 Maxillary First Premolars.

INTRODUCTION: The aim of this study was to investigate the root canal system morphology of maxillary first premolars by means of micro-computed tomographic imaging in a Swiss-German population. METHODS: The root canal configuration (RCC) of 115 maxillary first premolars (Mx1Ps) were investigated by means of micro-computed tomographic imaging and 3-dimensional imaging. The RCC and the physiological foramina results are described by a 4-digit system code. RESULTS: Twelve different RCCs were observed in 30 single-rooted Mx1Ps; 2-2-2/2 (30.0%), 1-2-2/2 (13.3%), 1-2-1/2 (10%), and 2-2-1/2 (10.0%) were the most frequent ones. Seven different RCCs were observed in 2-rooted Mx1Ps (n = 81) in which the 1-1-1/1 (56.8%), 1-1-1/2 (29.6%), and 1-1-2/2 (8.6%) in the buccal root and 1-1-1/1 (92.6%) and 1-1-1/2 (6.2%) in the palatal root RCCs appeared most frequently. Three-rooted Mx1Ps (n = 4) showed a 1-1-1/1 (100.0%) RCC in all roots. The buccal root canal in 2-rooted Mx1Ps had 1 physiological foramen in 59.3% and 2 in 40.7% and 1 to 6 accessory foramina in 38.2%. The palatal root canal showed 1 physiological foramen in 93.8% and 2 in 6.2% and 1 to 2 accessory foramina in 14.8%. Single-rooted Mx1Ps showed 1 physiological foramen in 10.0%, 2 in 70.0%, 3 in 13.3%, and 4 in 6.7% and 1 to 3 accessory foramina in 46.7%. CONCLUSIONS: The results of this study provide detailed morphologic RCC information of Mx1Ps in a Swiss-German population. Single-rooted Mx1Ps showed morphologic diversifications more frequently than 2- or 3-rooted Mx1Ps. Within 2-rooted Mx1Ps, the buccal root had higher RCC variety, accessory canals, and foramina number than the palatal root.