Table 3.
Characteristics of the included studies.
| Study Reference | Sample Size | Sample Type | Micro-CT Machine | Voxel Size (Resolution) | Software Used | Classification System | Technique | Results | Conclusion |
|---|---|---|---|---|---|---|---|---|---|
| [36] | 179 | Maxillary first molars * | Scanco Medical, Bruttisellen, Switzerland | 20 µm | Heidelberg, Germany Volume Graphics, VG-Studio Max 2.2; | fourfour-digit system | Endodontic access cavity was prepared with a high-speed and round bur, pulp stones were removed by ultrasonic scaler if needed, and at the end, the pulp chamber was rinsed with sodium hypochlorite following suction for drying and assessment of Micro-CT morphology of the root canal. | In mesiobuccal roots, the most prevalent root canal configurations were 1-1-1/1 (45.8%), 1-1-2/2 (25.1%), and 1-2-2/2 (10.1%), while in distobuccal roots, the most prevalent root canal configurations were 1-1-1/1 (97.2%) and 1-1-1/1 palatal (10.1%) (98.9 percent). | Maxillary first molars have a wide range of root canal configurations. According to this study, the mesiobuccal root has only one main foramen and one root canal entrance. |
| [37] | 125 | Permanent Anteriors | Scanco Medical, Bruttisellen, Switzerland | 20 µm | Heidelberg, Germany Volume Graphics VG-Studio Max 2.2; | four-digit system | Rendering software was used to visualize the various tooth structures generated from the 3-D reconstructions of the Micro-CT scans. Red was used to color the pulp chamber and RCS, white for the enamel/crown area, and transparent grey for the root/dentin area. The root canal configuration was determined when the roots were split into three. | The most prominent root canal configurations were 1-1-1/1 (56%), 1-2-1/1 (17.6%), and 1-1-1/2 (10.4%); however, 19 teeth had a total of nine root canal combinations (15.2 percent). | The study discovered variations in the morphology of root canal of anterior teeth in the German population, the most prevalent root canal configuration being 1-1-1/1. |
| [3] | 109 | Mandibular first premolar * | Scanco Medical, Bruttisellen, Switzerland | 16 µm | Heidelberg, Germany Volume Graphics VG-Studio Max 2.2; | four-digit system | The pulp chamber and root canals were red, the enamel was white, and the dentin was a translucent grey tint to distinguish tooth features. The root canal configuration was determined by dividing the roots into thirds and using the RCC method to generate a four-digit code system. The first three digits of the code system indicate the number of root canals at the coronal boundary of the coronal, middle, and apical thirds of a root; the fourth digit, divided by a slash, represents the number of physiological foramina. | The most common root canal configurations were 1-1-1/1 (70.6%), 1-1-2/2 (7.3%), 1-2-2/2 (7.3%), and 1-2-1/1 (7.3%). (5.5%). | The researchers discovered differences in the morphology of root canal of maxillary first premolars in the German-Swiss population, with 1-1-1/1 root canal configurations being the most prevalent (70.6 percent). |
| [38] | 500 | Maxillary and mandibular: Anteriors, premolars, and molars | Bruker Micro-CT, Kontich, Belgium | 26 μm | Bruker Micro-CT, Kontich, Belgium | Pucci & Reig (PR) (1944) and American Association of Endodontics | CT scanning for root canal morphology. | According to the PR, significant canals were found in 100% of the teeth studied, with the exception of the second mesiobuccal canal in the maxillary first and second molars, which had a frequency of 87 and 75 percent, respectively. In terms of the major canal, the AAE classification revealed the same results as the PR classification. | The variation of the RCS was accurately described by Micro-CT, which was proved by the PR and AAE classifications, with some discrepancies observed for upper molars. |
| [39] | 18 | human hemi-maxilla | Scanco Medical, Bruttisellen, Switzerland | 20 µm | Image processing language (version 5.15; Scanco Medical) | -- | The hemi-maxillae were taken from cadavers used in medical research and teaching (with prior agreement). Teeth from the human hemi-maxillae were extracted, washed with 3% NaOCl, and imaged using a CT scanner. | Thirteen first molars and fourteen second molars from eighteen cadavers were studied. Two canals were found in 100% of maxillary first molar MB roots (100 percent). Two canals were found in 57 percent of maxillary second molar MB roots. | Micro-CT canal numbers were considerably different from digital periapical radiograph counts in cadaver maxillary teeth, but not from 3-D CBCT counts. |
| [40] | 32 | Mesial roots of mandibular first molars | Bruker Micro-CT, Kontich, Belgium | 19.6 µm | Bruker Micro-CT, Kontich, Belgium | Vertucci’s classification | Group 1 and Group 2 (n = 10), Group 3 (n = 12). Based on Micro-CT scans and presenting several canal configurations, were evaluated followed by a clearing technique. |
Type I root canals were found in a considerably limited number of cleaned teeth, but type II root canals were found in all cases. | The evaluation technique and anatomy type significantly affected the accuracy of detecting mesial root canal shape among the tooth population examined. |
| [41] | 154 | Extracted human maxillary first molar mesiobuccal roots ** | SkyScan, Aartselaar, Belgium | 15.9 µm | On-Demand 3D software (Cybermed, Seoul, Republic of Korea). | Vertucci’s classification | The mesiobuccal roots of maxillary first molars with more than two canals were examined using 154 Micro-CT scans. Weine and Vertucci’s classifications were used to classify the root canal configurations of multiple-canalled MB roots. | 73.4 percent of the MB roots had multiple canals. The most common canal type was Weine type III. In 29.2 percent and 17.7 percent of MB roots, respectively, nonclassifiable configuration types were found. | The current study indicates that configuration classifications may need to be modified to reflect MB root morphology better. |
| [42] | 104 | Extracted human mandibular first molars | Bruker Micro-CT, Kontich, Belgium | 12.1 µm | Bruker Micro-CT, Kontich, Belgium | Vertucci’s classification | The mesial RCS were modelled in 3-D and assessed. | The morphology of mandibular molars’ mesial root canals was highly variable. The most common root canal configuration was Vertucci type IV (46.2 percent). | The morphology of the mesial root canals of mandibular molars was discovered to be very diverse in a Brazilian community. Clinicians must have a thorough understanding of the mandibular first molar mesial root canal architecture. |
| [43] | 100 | Extracted single-rooted human mandibular incisors | Bruker Micro-CT, Kontich, Belgium | 12.1 µm | Bruker Micro-CT, Kontich, Belgium | Vertucci’s classification | A Micro-CT system was used to scan the specimen. At five different levels in the apical third, the software was used to assess the length of the teeth and the number of canal orifices. | The mandibular central and lateral incisors had average lengths of 20.71 and 21.56 mm, respectively. One, two, or three canal orifices were discovered during a cross-section examination of the apical third. According to qualitative assessments of 3-D models of the RCS of the central and lateral incisor teeth, Vertucci’s type I (50 and 62 percent) the most common configuration. | The most common canal configurations in mandibular incisors were Vertucci’s types I and III. |
| [44] | 100 | Extracted mandibular first molars | Bruker Micro-CT, Kontich, Belgium | 19.6 µm | Bruker Micro-CT, Kontich, Belgium | Vertucci’s classification | The teeth were scanned in a Micro-CT device after being mounted on a custom attachment. | In 76 percent of the distal roots, a single root canal was discovered. In 13%, 8%, and 3% of the sample, respectively, two, three, and four canals were discovered. In 13 cases, the RCS configuration did not fit into Vertucci’s classification. |
Single root canals were seen in a significant percentage of the mandibular first molars’ distal roots. Canal configurations not included in Vertucci’s configuration scheme were discovered in 13% of the samples. |
| [45] | 169 | Extracted Maxillary first molars | Bruker Micro-CT, Kontich, Belgium | 60 µm | Bruker Micro-CT, Kontich, Belgium | Vertucci’s classification | By sectioning the molar at the cementoenamel junction, the palatal root was obtained. Micro-CT was used to scan the roots. | Vertucci type I was used for classifying all canals. Sixty-six percent of the canals had oval cross-sections. In 95 percent of the samples, the major foramen did not line up with the root apex. Straight canals accounted for just 8% of the canals. | Type I was discovered in the palatal roots. However, when treating these roots, several variables must be addressed, such as the frequent occurrence of moderate/severe curvatures, cross-sections, oval-shaped, and the presence of many roots. |
| [46] | 20 | Extracted maxillary first molars *** | SkyScan Micro-CT scanner (SkyScan 1172 X-ray Microtomography, Antwerp, Belgium), twelve-bit digital cooled CCD camera with fiber optics | 11.6 µm | T Converter (Amira 4.1; Mercury Computer System Inc., Chelmsford, MA, USA) (ECAD-2-12210 PMC; Mercury Computer System Inc.) | Weine and Vertucci’s classification | The mesiobuccal root of the maxillary first molar was placed in a 7 mm plastic container. To remove the adhering from hard and soft tissues, the roots were cleansed, and the mesiobuccal root was removed at the furcation level. | The root canal systems of a large percentage of the roots examined were complex, with 90 percent having a second mesiobuccal canal. Only 60% of root canals could be classified using the Weine classification system, while 70% could be classified using the Vertucci system. | Micro-CT enables a more thorough analysis of root canal anatomy, revealing that the morphology of the mesiobuccal root of maxillary first molar teeth is complicated, and that existing morphological categories are insufficient to capture this complexity. |
| [47] | 340 | Extracted Mandibular incisors | Skyscan 1174 (Bruker Micro-CT, Kontich, Belgium) | 19 µm | NRecon software, CTAn v.1.12 software (SkyScan, Belgium) | Vertucci classification | The numbers of canals were categorized using the Vertucci classification system, and the apical third was measured in 3-D. For each anatomic categorization, the data was reported as a median and range. | A single root canal was found in all of the specimens (N = 257). Vertucci type III (N = 56) was the second most common morphology. This anatomical group accounts for 92 percent of the total sample. At the 1 mm apical level, oval canals were found 16.7% of the time for Vertucci type I and 37.5 percent of the time for Vertucci type II. At the 3 mm apical level, oval canals increased to 32.4 percent and 76.2 percent for Vertucci type I and III, respectively. | Type I and III forms were found in 92 percent of the mandibular incisors examined. In these morphological configurations, oval-shaped canals in the apical third were common, and they were more common in type III. |
| [48] | 100 | Extracted fused-rooted maxillary second molar | Skyscan 1174 (Bruker Micro-CT, Kontich, Belgium) | 19.6 µm | (NReconv. 1.6.3; Bruker Micro-CT), CTAn v. 1.16 (Bruker Micro-CT), and CTVolv. 2.3 software (Bruker Micro-CT). | Vertucci classification | At 1, 2, and 3 mm from the anatomical apex of the fused roots, the morphology of the RCS was assessed using the Vertucci classification. | Type 3, Distobucal root fused with Palatal root (27 percent), Type 4, Mesiobucal root fused with Distobucal root, and Palatal root fused with MB or DB roots were the most common root canal fusions (32 percent). | In the root canal system of maxillary second molars with fused roots, merging canals were common. |
| [49] | 118 | Mandibular first molars * | Scanco Medical, Bruttisellen, Switzerland | 20 µm | Heidelberg, Germany Volume Graphics, VG Studio Max 2.2; | Four-digit system | The pulpal access cavity was prepared with a diamond bur at a high speed, pulp stones were eliminated with an ultrasonic scaler if necessary, and the pulp chamber was rinsed with sodium hypochlorite at the end. | The most common root canal configurations in the mesial root were 2-2-2/2 (31.4%), 2-2-1/1 (15.3%), and 2-2-2/3 (11.9%); there were also 24 additional root canal configurations in this root. In the distal root, 1-1-1/1 (58.5%), 1-1-1/2 (10.2%), and 16 different root canal configurations were found. | The root canal configurations of mandibular first molars vary greatly. Many morphologic differences were found in both the mesial and distal roots. |
| [50] | 123 | Maxillary second molar * | Scanco Medical, Bruttisellen, Switzerland | 20 µm | Heidelberg, Germany Volume Graphics VG Studio Max 2.2, | Four-digit system | Endodontic access cavities were generated under a microscope for further investigation of the tooth’s internal morphology, making sure not to affect the root canal system morphology or the pulp chamber floor. | The most common root canal configurations in the mesiobuccal root were 2-2-2/2 (19.5%), 2-2-1/1 (14.6%), and 2-1-1/1. (13.0 percent). A total of 93.5 percent of distobuccal roots and 96.7 percent of palatal roots had a 1-1-1/1 arrangement, respectively. | The most common root canal configurations in the mesiobuccal root were 1-1-1/1 (26%). |
| [51] | 116 | Maxillary second premolar * | Scanco Medical, Bruttisellen, Switzerland | 16 µm | Heidelberg, Germany Volume Graphics VG Studio Max 2.2, | Four-digit system | The maxillary first premolars were scanned with a Micro-CT scanner. The pulp chamber and Root canal configuration (RCC) were depicted in red to identify tooth anatomy, the enamel in white, and the dentin in a transparent grey tint. | The most seen (RCCs) in Maxillary second premolar (Mx2)s) were 1-1-1/1 (35.3%), 1-1-1/2 (21.6%), and 2-1-1/1 (14.7 percent). A total of 11 less common RCCs were discovered. There was just one root in all Mx2Ps. | Within the study’s limits, maxillary second premolars had a significant RCC. |
| [52] | 260 | 130 Maxillary and 130 Mandibular molars *** | (Bruker micro- CT, Kontich, Belgium) Skyscan 1174 | 43.3 µm | (Materialize, Leuven, Belgium) Mimics 17.01 | Weine’s classification | A semiautomated segmentation method was used to recreate the interior and exterior tooth anatomy. The basic tooth model and the pulp cavity model were combined using a Boolean formula to create a new tooth model. The cavities in this tooth model were filled in. After that, the teeth models were evaluated qualitatively and quantitatively. | A single fused root (51.5 percent) and a single root canal system (49.2 percent) were the most common root/canal types for maxillary molars; typical three-rooted molars were only found in 25.4 percent, and secondary MB canals were only seen in 2 percent. 25% The type 1-1 canal was the most common configuration for mesial and distal root canal systems. A total of 47.7% of mandibular molars were single-rooted, while 32.3 percent had a single root canal system; 20 single-rooted and 60 double-rooted molars had separate mesial and distal root canal systems (61.5%). | The root canal system of the third molars can be physically different in several ways. The degree of canal variation was small in most cases, and the canal form was clear. |
| [53] | 80 | Mandibular canines | SkyScan 1173 v2 Micro-CT (Bruker Micro-CT, Kontich, Belgium) | 12.1 μm | NRecon software (v1.6.1.0; Bruker, Kontich, Belgium), (CTAn v. 1.14.4, Bruker Micro-CT Kontich, Belgium), and (CTVol v. 2.2.1, Bruker Micro-CT, Kontich, Belgium) | Vertucci’s classification | The number of canals, root canal configurations according to Vertucci’s classification, root length and number and location of lateral canals, the presence of apical delta, perimeter, roundness, and minor and major diameters at cervical, medium, and apical thirds and 1 mm from the foramen were evaluated. | All canals were classified as Vertucci Type I. Lateral canals were verified in 42.4% of the roots, in apical third. The cross-sections at the cementoenamel junction and 1 mm from the apex were oval in 38.3% and 79.4% of the canals, respectively. | The root canal of single-rooted canines evaluated in the present study was classified as Vertucci type I. |
| [54] | 186 | Mandibular first premolar | SkyScan 1278, Bruker, Kontich, Belgium | 50 μm | CTAn v.1.12 software (Bruker Micro-CT), Kontich, Belgium | Vertucci’s and Ahmed’s classification | All the samples were emerged in 5% sodium hypochlorite for 30 min and reserved in 10% neutral buffered formalin. Dental calculus was removed by using an ultrasonic scaler and stored in a moisturizing solution at room temperature. All teeth were scanned using a high- resolution Micro-CT device. | Radicular grooves were observed in 39.25% of teeth. The ASUDAS scores for radicular grooves were 60.75%, 13.98%, 12.36%, 10.22%, 2.15%, and 0.54%, from grade 0 to grade 5, respectively. | Mandibular first premolars showed a wide range of anatomical variations. Ahmed’s criteria allowed for the classification of the internal anatomy of the root canal in a more precise and practical way than Vertucci’s criteria. Teeth with multiple root canals had a higher incidence of radicular grooves and a more complex morphology compared with teeth with a single root canal. |
| [55] | 520 | Mandibular incisors | SkyScan 1176, Bruker Micro-CT, Kontich, Belgium | 17.42 μm | CTAn (V1.11.8; SkyScan, Belgium) software, NRecon (V1.6.4,7; SkyScan, Belgium) software, and Data Viewer (V1.5.1.2; SkyScan, Belgium) software | -- | All the samples were evaluated 9 mm from the apex using digital radiographs in buccolingual (BL) and mesiodistal (MD) directions. Root canal diameters obtained in measurements were 3, 6, and 9 mm from the apex. | Between all the incisors, 121 (23.3%) were flattened; 215 (41.3%) oval; 142 (27.3%) rounded; 23 (4.5%) round; and 19 (3.6%) with BL flatness 9 mm from the apex. | Oval root canals are predominant in mandibular incisors with a single canal at 9 mm from apex. |
| [56] | 93 | Mandibular second molar | Microcomputed tomography (VGStudio Max 2.2; Volume- graphics, Heidelberg, Germany) | 20 μm | VGStudio Max 2.2; Volume- graphics, Heidelberg, Germany software | -- | Teeth were cleaned and access cavities were prepared. The pulp chamber roof was carefully removed by cutting along the pulp chamber walls. When required, ultrasonic tips were used to re- move pulp stones. | The most frequently observed root canal configurations in the mesial root were 2-2-1/1 (32.3%), 2-2-2/2 (28.0%), 1-1-1/1 (6.5%), and 2-1-1/1 (6.5%); an additional twelve different root canal configurations were also found here. In the distal root, the RCC 1-1-1/1 was observed in 81.7%; another ten different root canal configurations with a frequency of less than 5% were also observed in this root. | The root canal configuration of mandibular second molars showed a great variety. When compared with the first mandibular molar in a historical control from the same sample, the mandibular second molar presented less morphological diversifications. |
| [57] | 47 | Maxilary first and second molar | Nikon Metrology Inc, Brighton, MI, USA | -- | VG Studio MAX 2.1 software (Volume Graphics GmbH, Heidelberg, Germany) | -- | Teeth were mounted on a cylindrical specimen holder and scanned by mCT. | The palatal root of maxillary first molars was found to have statistically significantly thinner dentin than second molars on the palatal aspect of the root 8–11 mm from the apex, correlating to the coronal and middle thirds of the root. First molar palatal roots also had a statistically significantly wider canal mesiodistally than second molars at 13–15 mm from the apex. | The absence of an apical constriction in 76.6% of the specimens highlights the importance of creating an apical seat through instrumentation to maintain obturation materials. |
| [58] | 96 | Maxillary first molar misiobuccal root | Micro-CT system (Skyscan 1173; Bruker Co., Kontich, Belgium) | 21.39 μm | NRecon soft- ware v.1.6.9.4 (Bruker Co., Kontich, Belgium), InstaRecon® v.1.3.9.2 (IR-CBR Server, University of Illinois Research Park, Illinois, EUA), CTAn v.1.14.4.1, Dataviewer, and CTVox software (Bruker Co., Kontich, Begium) | Weine’s and Vertucci’s classification | Three-Dimensional images of misiobuccal root were analyzed regarding the number of pulp chamber orifices, the number and classification of the canals, the presence of accessory canals in different thirds of the root, and the number and type of apical foramina. | A single entrance orifice was found in 53.0% of the samples, two in 43.9%, and only 3.1% had three orifices. The second mesiobuccal root canal (MB2) was present at some portion of the root in 87.5% of the specimens. A single apical foramen was present in 16.7%, two in 22.9%, and three or more foramina in 60.4% of the roots. Only 55.3% and 76.1% of the root canals could be arranged by Weine’s and Vertucci’s classifications, respectively. | The most commonly found type in this study was Weine type IV/Vertucci type V, and accessory canals were more detected at the apical third, followed by the middle and cervical thirds of the root, respectively. |
| [59] | 374 | Mandibular first, second and thirrd molar | Micro-CT scanner (Nanotom S, General Electric) | 13.68 μm | CTVox, CTAnalyser and CTVol (SkyScan®) | Vertucci’s classification | All the molars were scaned with a Micro-CT scanner (Nanotom S, General Electric) | In the mesial roots of mandibular molars, the most frequent Vertucci type of canal configuration was type IV, except for the mandibular third molar where type I was most common. Type I was most common in the distal root. | Knowledge of the complex anatomy of the mandibular molars can make root canal therapy more likely to succeed. |
| [60] | 89 | Mandibular incisor | SkyScan 1173 microtomograph (Bruker Micro–CT Kontich, Belgium) | 12.11 μm | NRecon v1.6.6.0 software (Brucker Micro-CT, Kontich, Belgium) | Vertucci’s classification | All the lower incisors were scanned with a micro–CT and reconstructed with NRecon software. Two-Dimensional parameters (perimeter, root length, circularity, and canal diameter) and 3D parameters (volume, surface area, and structure model index) were evaluated with CTAn and CTVol software. | It was found that 89.9% of the canals had a single main root canal (type I), followed by type II (6.7%) and III (3.4%), while 5.6% of the specimens presented lateral canals and 1.1% had an apical delta. Mean volume and surface area were 31.80 mm3 and 90.58 mm2, respectively. The most prevalent shape of the root canal at CEJ level was circular (41.6%) and 1 mm from the apex, and 73% of the samples were classified as oval. | Incisors have a single root with a relatively simple anatomy, and internal anatomical variations may offer a high degree of technical complexity. |
| [61] | 136 | Mandibular first molar | Micro-CT system (mCT-50; Scanco Medical, Bassersdorf, Switzerland) | 30 μm | Mimics 18.0 software (Materialise, Leuven, Belgium) | -- | All the teeth were scaned with Mimics 18.0 software (Materialise, Leuven, Belgium). The 3-dimensional models of the teeth with root canal systems were constructed and made transparent by adjusting the transparency. The tooth axes based on the shape of the tooth was calculated automatically based on principal component analysis. | The measurements of the maximum curvature of coronal root canals in the axial direction were: in three-canals two-rooted teeth, the average angles of curvatures were 23, 25, and 11 for MB, ML, and DB canals; in four-canals two-rooted teeth were 23, 25, 12, and 16 for MB, ML, DB, and DL canals, respectively; in four-canals three-rooted teeth were 25, 27, 17, and 39 for MB, ML, DB, and DL canals, respectively. | The results of this study are similar to those previously obtained using CBCT and can help us design endodontic approaches. |
| [62] | 30 | Premolar | X-Ray microfocus CT scanner (SkyScan 1072; SkyScan, Aart- selaar, Belgium) | 19.1 μm | software (NRecon V1.4.0; SkyScan), CT-analyzer V1.6; SkyScan | -- | All the radiographs were made in the buccolingual (BL) and mesiodistal (MD) direction to evaluate the root canal anatomy and to identify the radiographic apex using X-ray microfocus CT scanner (SkyScan 1072; SkyScan, Aart- selaar, Belgium). | At all levels of analysis, the BL diameter was greater than the MD diameter for both the canal and the root. Generally, canal and root increased coronally. Buccal and lingual wall thicknesses were greater than mesial and distal at all levels. Canal diameters were at 1 mm from the apex. | Oval canals are frequently present, including in the last few apical millimeters of the root canals. |
| [63] | 105 | Mandibular premolar | Micro-CT system (SkyScan 1174v2; Bruker Micro-CT, Kontich, Belgium) | 18 μm | NRecon v.1.6.3; Bruker Micro-CT | -- | The samples were mounted on a custom attachment and scanned in a Micro-CT system (SkyScan 1174v2; Bruker Micro-CT, Kontich, Belgium) | Overall, specimens had one root with a main canal that divided into mesiobuccal, distobuccal, and lingual canals at the furcation level. Mean length of the teeth was 22.9 and 2.06 mm, and the configuration of the pulp chamber was mostly triangle-shaped. Mean distances from the furcation to the apex and cementoenamel junction were 9.14, 2.07, 5.59, and 2.19 mm. | Type IX configuration of the root canal system was found in 16 of 105 (15.2%) extracted mandibular premolars with radicular grooves. |
| [64] | 72 | Maxilary first molar | Micro-CT scanning (SkyScan1174; Bruker Micro-CT, Kontich, Belgium) | 22.4 μm | Mimics 15.01 (Materialise, Leuven, Belgium) software | Vertucci’s classification | Each specimen was scanned along the tooth axis with a voxel size of 22.4 μm using Micro-CT scanning (SkyScan1174; Bruker Micro-CT, Kontich, Belgium). The root canal configuration in the MB roots was examined and described by Vertucci’s classification. | MB2 canals were detected in 76.4% (55/72) of the total sample teeth. The incidence of accessory canals was 56.9% (41/72). The mean ratio of D/d was generally “greatest to least”. | The ocrurrence of finding MB2 in maxilary second molar is high. |
| [65] | 178 | Mandibular firstpremolar | Micro-CT scanner (Micro-CT Inveon; Siemens Medical Solutions, Knoxville, TN, USA) | 15 μm | Cobra software (Siemens Medical Solutions, Knoxville, TN) | Vertucci’s classification | All samples were scanned using a Micro-CT scanner (Micro-CT Inveon; Siemens Medical Solutions, Knoxville, TN) with voxel sizes of 15 μm × 15 μm × 15 μm. The in-built Cobra software (Siemens Medical Solutions, Knoxville, TN) was used for the 3-D reconstruction and analysis. | Almost all the samples were single-rooted (99.4%). In total, 64.04% of teeth possessed type I canal systems, while 34.27% had two canals, and 1.69% had three canals. According to ASUDAS, the scores of radicualr grooves were 56.74%, 16.85%, 12.36%, 10.11%, 3.37%, and 0.56%, respectively, from grade 0 to grade 5. The roots with radicular grooves (grade 3 or 4) were defined as Tome’s anomalous root and these roots have a high incidence of C-shape configurations (66.67%) and multiple-canal systems (100%). | There is obvious variation of the root anatomy and root canal morphology of mandibular first premolar among the southwestern Chinese population, which is very complex and requires careful assessment for endodontic treatment. |
| [66] | 240 | Mandibular molar | Micro-CT scanner (SkyScan 1174, SkyScan, Bruker, Belgium) | 32.17 μm | software (SkyScan 1174, SkyScan, Bruker, Belgium) | Pomeranz ‘s classification | All the samples were scaned with a Micro-CT scanner (SkyScan 1174, SkyScan, Bruker, Belgium). | The evaluation of three-dimensional (3-D) images of this study showed that no significant difference was found between the percentage of MM (27.5%) and MD canals (22.5%) (p = 0.2064); however, there was a significant difference between the percentage of teeth having both extra canals (10%) and teeth having only one of these canals (p < 0.05). The confluent configuration (71%) was significantly higher than the other configurations (p < 0.05). | The presence of MM canals was higher than that of MD canals; however, the difference was nonsignificant. The occurrence of both extra canals in the same tooth was less significant than the occurrence of only one of either MM or MD canals. The extra canals detected had a higher percentage of the confluent configuration rather than the fin or the independent configurations. |
| [67] | 274 | Maxilary pemolars and molar | Micro CT inveon; Siemens Medical Solutions, Knoxville, TN) | 15 μm | MICs 10.01 software (Materialise, Leuven, Belgium | Vertucci’s classification | After acess cavity pulp chamber was cleaned and an 15 k file was insered in the canal, X-rays were taken from the misiodital and buccolingual direction. | The root canals of the maxillary posterior teeth showed more significant curvature in the mesiodistal direction than in the buccolingual direction (p < 0.05). The MB2 root canal of maxillary molars showed severe bending in the mesiodistal direction: 25.16 ± 6.6 degrees and 28.05 ± 8.65 degrees in first and second molars, respectively. The detection rate of MB2 was 48% in maxillary first molars and 32% in maxillary second molars. | The maxillary posterior teeth showed obvious root canal bending variation and root canal configuration differences. Mostly, the root canals of maxillary premolars showed moderate curvature, while the root canals of maxillary molars showed moderate to severe bending. |
| [68] | 11 | Third molar | The Skyscan 1072 X-ray computed microtomograph (Skyscan, Aartselaar, Belgium) | 19.74 μm | ANT software (release 2.05, Skyscan, Aartselaar, Belgium) | -- | The enamel crown was sealed onto poly (methylmethacrylate) blocks with com- mercial cyanoacrylic glue. Poly (methylmethacrylate) is a radiolucent polymer and these blocks allowed the teeth to be handled easily inside the Micro-CT system. The Skyscan 1072 X-ray computed microtomograph (Skyscan, Aartselaar, Belgium) was used for scanning. | Most roots had a single canal that tapered to the apex. Several canals seemed to have a thin, ribbon-like appearance with focal areas of contact between the walls of the dentine. | Microcomputed tomography seems to be a promising way of studying dental anatomy. |
| [1] | 100 | Mandibular canine | lCT scanner (SkyScan 1174v2; Bruker Micro-CT, Kontich, Belgium) | 19.6 μm | NRecon v. 1.6.3; Bruker- Micro-CT and CTAn v. 1.12 software (Bruker Micro-CT) | -- | After being washed in running water for 24 h, each tooth was dried, mounted on a custom attachment, and scanned in an lCT scanner (SkyScan 1174v2; Bruker Micro-CT, Kontich, Belgium). | The length of the roots ranged from 12.53 to 18.08 mm. Thirty-one specimens had no accessory canals. The location of the apical foramen varied con siderably. The mean distance from the root apex to the major apical foramen was 0.27 and 0.25 mm, and the major diameter of the major apical foramen ranged from 0.16 to 0.72 mm. Mean major and minor diameters of the canal 1 mm short of the foramen were 0.43 and 0.31 mm. | The anatomy and morphology of the root canal of single-rooted canine varied widely in different levels of the root. |
| [69] | 208 | Mandibular incisors | Micro-CT scanner (μCT- 50; Scanco Medical, Bassersdorf, Switzerland) | 30 μm | MeVisLab v3.2 software (MeVis Medical Solutions AG, Bremen, Germany) | Vertucci’s classification | All the samples were scaned with a Micro-CT scanner (μCT- 50; Scanco Medical). | Three canal categories, labeled as Single (77.88%), Merged (15.87%), and Separated (6.25%), were summarized. The most frequent constriction type in main foramina was single constriction (42.53%). Wide and narrow diameters are in a single main foramen. During the virtual root-end resection, 97.12% of roots underwent successful resection at the 2 mm level. | This study provides detailed information about the root canal morphology and thickness of the crown and root of mandibular incisors in a Chinese population. The most frequent canal configuration was the Single type (77.88%), and more than half (55.2%) of the specimens demonstrated the presence of a constriction. |
| [70] | 101 | Maxilary first molar | SkyScan 1272 scanner (Bruker Micro-CT, Belgium) | 10 μm | NRecon software (Bruker Micro-CT). CTAn software (Bruker Micro-CT)and CTVol software (Bruker Micro-CT) | Vertucci’s classification | All the samples were scaned with a SkyScan 1272 scanner (Bruker Micro-CT, Belgium). | Eighty-three (82.18%) mesiobuccal roots had multiple canals. The most common canal type is type IV (45.5%), followed by type II (17.8%) and I (17.8%) canals. Type III, V, VI, VII, and VIII canals are less than 10% in total. Seven additional canal types were seen for 10% in total. Fourteen (13.86%) distobuccal roots had multiple canals, and the predominant canal type is type I (86.1%), followed by type II (5.9%) and V (4%) canals. Three additional canal types were observed for 4% in total. All palatal roots possessed the simplest type I canal. | The results of this study reiterate that the root canal configuration of Burmese MFMs is quite complex, especially the mesiobuccal root possessing the highest incidence of additional canals, lateral canals, and apical delta, and isthmuses among three roots. |
| [71] | 100 | Maxilary second premolar | SkyScan 1172 X-ray Micro-CT scanner (Bruker Corp., Antwerp, Belgium) | 27.4 μm | SkyScan CT-Volume v2.2 software (Bruker Corp., Antwerp, Belgium) | Vertucci classification | All the samples were scaned by SkyScan 1172 X-ray Micro-CT scanner (Bruker Corp., Antwerp, Belgium). | Number of roots were: one root (67%), two roots (30%), three roots (3%), and root canal clasifications were IV and V (both found in 23% of teeth), followed by type I (17%), type III (9%), type II (7%), and type VII (2%). | The root canal morphology of maxillary second premolars in the Saudi Arabian subpopulation is complex and requires cautious evaluation prior to endodontic treatment. |
| [72] | 25 | Maxilary second molar | Micro-CT scanner (SkyScan 1174v2; SkyScan N.V., Kontich, Belgium) | 22.6 μm | NRecon v1.6.4; SkyScan | -- | A Micro-CT scanner (SkyScan 1174v2; SkyScan N.V., Kontich, Belgium) was used for scaning all teeth. | The specimens were classified as types I (n = 16), II (n = 7), and III (n = 2). The size of the roots was similar (p > 0.05), and most of them presented straight with one canal, except the mesiobuccal that showed two canals in 24% of the samples. | Considering the evaluation of the external and internal anatomy of four-rooted maxillary second molars, it can be concluded that most of the samples were classified as type I. |
| [73] | 101 | Mandibular canine | Bruker SkyScan | 10.0 μm | Bruker Micro-CT, Control software version 1.1.19, Kontich, Belgium | -- | Bruker SkyScan was ued for scaning for samples. | The root canal configarations were 1-1-1/1 (74.5%) and 1-1-1/2 (14.3%). Physiological foramenwas observed in 80.6% of the MaCas, two in 16.3%, three in 1.0%, and four in 2.0%. | Single-rooted mandibular canines (MaCas) were the most frequently observed (97.0%) ones. |
| [74] | 115 | Mandibular first premolar | Siemens Inveon CT, Munich, Germany | 14.97 μm | Mimics 10.01 software (Materialise, Leuven, Belgium) | Vertucci classification | Mimics 10.01 software (Materialise, Leuven, Belgium) was used for 3-D imaging. | Canal configuration types I (65.2%), III (2.6%), V (22.6%), and VII were identified (0.9%). | The data obtained in this study revealed com- plex root morphology with a high prevalence of multiple canals, more than half of which exhibited type I canal patterns. |
| [75] | 55 | Mandibular first molar | Micro-CT system (SkyScan 1174v2; Bruker- Micro-CT, Kontich, Belgium) | 19.6 μm | NRecon v.1.6.3; Bruker Micro-CT, Kontich, Belgium | -- | Three-Dimensional models were reconstructed after binarization of the source images, exported by Micro-CT, Kontich, Belgium). | Mesial roots showed a complex distribution of the root canal system in comparison to the distal roots. Almost all distal roots had one root canal and one apical foramen with few accessory canals. | Distolingual roots generally have a short length, severe curvature, and a single root canal with a low apical diameter. |
| [76] | 115 | Maxilar first premolar | Micro-CT unit (mCT 40; Scanco Medical, Bru€ttisellen, Switzerland) | 16 μm | VGStudio Max 2.2; Volume Graphics, Heidelberg, Germany | -- | A Micro-CT unit (mCT 40; Scanco Medical, Bru€ttisellen, Switzerland) was used for scanning all the samples. | Root cannal configarations were in 30 single-rooted teeth, 2-2-2/2 (30.0%), 1-2-2/2 (13.3%), 1-2-1/2 (10%), and 2-2-1/2 (10.0%), and in two-rooted misial roots 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’s root canal configaration appeared most frequently. | The results of this study provide detailed morphologic root canal configuration information. Single-rooted teeth showed morphologic diversifications more frequently than two- or three-rooted premolars. Within two-rooted premolars, the buccal root had higher root canal configaration variety, accessory canals, and foramina numbers than the palatal root. |
| [77] | 40 | Mandibular first molar | micro- CT scanner (SkyScan 1172 X-ray Micro-CT; SkyScan, Ant- werp, Belgium) | -- | SkyScan Micro-CT software for 3-D analysis on sagittal, coronal, and axial slices | Vertucci classification | Forty mandibular first molars were cleaned and stored. Micro-CT scanner (SkyScan 1172 X-ray Micro-CT; SkyScan, Ant- werp, Belgium) were used to scane all the teeth. | The mesial roots of mandibular first molars had canal configurations of type I (15%), type II (7.5%), type III (25%), type IV (10%), type V (2.5%), type VI (7.5%), and type VII (7.5%). | Frequent variations were detected in mesial roots of mandibular first molars. Clinicians should take into consideration the complex structure of the root canal morphology before commencing root canal treatment. |
| [78] | 30 | Maxillary first molar | SkyScan 1072, SkyScan b.v.b.a., Aartselaar, Belgium | 19.1 μm | NRecon V1.4.0; SkyScan b.v.b.a | Vertucci classification | Maxillary first molar teeth having three separate roots were randomly selected for microtomographic analysis. | The MB2 canal was present in 80% of specimens and was independent in 42% of these cases. When present, the MB2 canal merged with the MB1 canal in 58% of cases. | The MB root canal anatomy was complex: a high incidence of MB2 root canals, isthmuses, accessory canals, apical deltas, and loops was found. |
| [79] | 208 | Maxilary first and second molar | CTVox, CTAnalyser and CTVol (SkyScan®) | 13.68 μm | CTVox, CTAnalyser and CTVol (SkyScan®) | Vertucci classification | After cleanig all the maxilary molars, they were scaned by CTVox, CTAnalyser and CTVol (SkyScan®). | The mesiobuccal root was the most variable with respect to canal configuration, with type I being the most common configuration followed by type II and type IV. Type I was the most common canal configuration in the distobuccal and palatal root. | It is important to know the morphology of the root canal system in order to perform endodontic treatment correctly. |
| [22] | 50 | Mandibular first premolar | Micro-CT scanner (Sky- Scan 1172 X-ray micro-tomograph; SkyScan, Antwerp, Belgium) | 11.94 μm | NRecon/InstaRecon reconstruction en- gine; SkyScan | Vertucci’s classification | A Micro-CT scanner (Sky- Scan 1172 X-ray micro-tomograph; SkyScan, Antwerp, Belgium) was used to scan all the mandibular first premolar. | Variable root canal configurations were types I, III, IV, V, and VII. The examined teeth exhibited the following two additional root canal configurations, which did not fit the classification: types 1–2–3 and types 1–3. | A complex morphology of mandibular first premolars were observed with a high prevelence of multiroot canal systems. |
| [80] | 90 | Maxilary first molar | HMX 225-ACTIS 4, Tesco, Inc | 50 μm | VGStudio Max 2.2; Volume- graphics, Heidelberg, Germany software | Weine’s classification | Before measuring, the 3-D recontracttion was prepared using volumetric analysis. | Single root canal was observed in 44%. | The authors conlcuded that the images were classified based on numeric criteria obatained by Micro-CT. |
| [81] | 46 | Maxilary first molar | Micro-CT (SkyScan 1072; SkyScan, Aartselaar, Bel- gium) | 19.5 μm | V-Works 4.0; Cybermed, Seoul, Korea | -- | Misiobuccal root of maxilary first molar were scaned using Micro-CT (SkyScan 1072; SkyScan, Aartselaar, Belgium). | In these MB roots, 65.2% had two canals, 28.3% had only one canal, and 6.5% had three canals. The most common root canal configuration was two distinct canals (type III: 37.0%), followed by one single canal (type I: 28.3%), two canals that joined together (type II: 17.4%), one canal that split into two (type IV: 10.9%), and three canals (type V: 6.5%). | Micro-CT provided an in-depth analysis of canal configurations, as well as length, curvature, and location of calcified segments. |
| [12] | 78 | Maxilary third molar | Micro-CTscanner(SkyScan® 1172, Aartselaar, Belgium) | 13.68 μm | NRecon software (SkyScan®) | -- | All the maxillary third molars were scanned by Micro-CTscanner(SkyScan® 1172, Aartselaar, Belgium). | Maxillary third molars possessed one or three roots, which principally curved buccally/palatally (75.9%), had one to four root canals, and typically no apical constriction (84.4%). The average external root length was 11.89 ± 1.53 mm, while root canal length was 10.18 ± 0.35 mm. | In some cases, the anatomy of maxillary third molars may not be as complicated as previously documented. During root canal treatment, the frequent deviation of the apical foramen from the radiographic apex should be considered, as should the absence of an apical constriction in the majority of cases. |
| [82] | 30 | Mandibular first molar | SkyScan 1172; Bruker- Micro-CT, Kontich, Belgium | -- | CTVol v. 2.3.2.0 software (Bruker- Micro-CT) | -- | All the roots were scaned by SkyScan 1172; Bruker- Micro-CT, Kontich, Belgium. | Mesiobuccal (MB) and mesiolingual (ML) canals were positioned within 2.5 mm from the anatomic apex, and the origin and exit of accessory canals were observed mostly between 1.0 and 2.0 mm from the apex in the group. | The presence of bifid apex in the mesial root of mandibular first molars might be a predictive factor for a complex canal anatomy at the apical third with an increasing number of accessory canals. |
* Stored in 70% Alcohol. ** Stored in 0.5% sodium azide solution at 4 °C. *** Stored in 10% formalin.