Molar Mesial Roots Research Articles

Safe sites in the mandibular buccal shelf for orthodontic mini-screws: Tomographic study in different facial types

Objectives: The objective of this study was to verify safe sites on the mandibular buccal shelf (MBS) for extra-alveolar mini-screw insertion according to facial type. Material and Methods: In this retrospective study, 84 cone-beam computed tomography scans were equally divided into three groups according to the patient’s facial type: Group 1, hyperdivergent; Group 2, neutral; and Group 3, hypodivergent. The total buccal alveolar bone thickness was measured in five zones between the mesial root of the first molar and the distal root of the second molar, 3, 6, and 9 mm apical to the cementoenamel junction (CEJ). Results: MBS areas with adequate thickness for temporary anchorage device (TAD) insertion were as follows: Group 1, second molar distal root 9 mm from the CEJ; Group 2, second molar distal root 6 and 9 mm from the CEJ; and Group 3, second molar mesial root 9 mm from the CEJ and second molar distal root 6 and 9 mm from the CEJ. Conclusion: The safe zones on the MBS for TAD insertion were located on the distal root of the second molar, 9 mm from the CEJ, for all facial types. For neutral and hypodivergent patients, the site located on the second molar distal root, 6 mm from CEJ, was included; for hypodivergent patients, the site located on the second molar mesial root, 9 mm from the CEJ, was included.

The osteoclastic activity in apical distal region of molar mesial roots affects orthodontic tooth movement and root resorption in rats

The utilization of optimal orthodontic force is crucial to prevent undesirable side effects and ensure efficient tooth movement during orthodontic treatment. However, the sensitivity of existing detection techniques is not sufficient, and the criteria for evaluating optimal force have not been yet established. Here, by employing 3D finite element analysis methodology, we found that the apical distal region (A-D region) of mesial roots is particularly sensitive to orthodontic force in rats. Tartrate-resistant acidic phosphatase (TRAP)-positive osteoclasts began accumulating in the A-D region under the force of 40 grams (g), leading to alveolar bone resorption and tooth movement. When the force reached 80 g, TRAP-positive osteoclasts started appearing on the root surface in the A-D region. Additionally, micro-computed tomography revealed a significant root resorption at 80 g. Notably, the A-D region was identified as a major contributor to whole root resorption. It was determined that 40 g is the minimum effective force for tooth movement with minimal side effects according to the analysis of tooth movement, inclination, and hyalinization. These findings suggest that the A-D region with its changes on the root surface is an important consideration and sensitive indicator when evaluating orthodontic forces for a rat model. Collectively, our investigations into this region would aid in offering valuable implications for preventing and minimizing root resorption during patients’ orthodontic treatment.

Prevalence of Isthmi and Root Canal Configurations in Mandibular Permanent Teeth Using Cone-Beam Computed Tomography.

While root canal anatomy in Middle Eastern populations is well-studied, research on isthmi in mandibular permanent teeth from this region is limited. This retrospective study used cone-beam computed tomography (CBCT) to examine isthmi prevalence and location, as well as root canal morphologies (per Vertucci's classification) in mandibular permanent teeth from a subpopulation in Ardabil, Iran. The study is aimed at enhancing our understanding of dental anatomical variations in Middle Eastern populations. A total of 3566 teeth from 384 CBCT scans were evaluated in this retrospective study. Mandibular teeth were evaluated on sagittal, coronal, and axial sections regarding the presence of isthmus and root morphology (Vertucci's classification). CBCT scans of 197 males (51.3%) and 187 females (48.7%) were evaluated, with a mean age of 41.1 ± 11.4 years. Isthmi were most prevalent in molar mesial roots, typically located in the middle third for anterior teeth and first premolars and cervical third for posterior teeth. While gender did not play a significant role, the presence of an isthmus in the mesial root of the left second molars was associated with a younger mean patient age (p < 0.05). Root morphology varied across tooth types. Central and lateral incisors predominantly showed Vertucci's Types I and III. Canines and premolars were mostly Type I, with some variation. Molar mesial roots frequently exhibited Types IV and II, while distal roots were predominantly Type I. Statistically significant differences were found between morphology and gender in the first left premolar (Type I more common in women; Type V in men; p < 0.001) and in the right canine (Type I more prevalent in men; Types III and V more prevalent in women; p < 0.001). The results revealed wide variations in root canal morphology and a relatively high prevalence of isthmi in the study population. Our findings suggest a potential difference in tooth anatomy based on sex and a relationship between age and the presence of isthmi.

Comparative Evaluation of Different Irrigant Agitating Devices for Debris Removal from the Mesial Roots of Mandibular Molars: An In Vitro Study.

To evaluate the efficiency of debris removal from the mesial root canals and isthmus of mesial roots of mandibular molars after final irrigant agitation with XP-endo Shaper, EndoVac (EV), plastic finishing file, and conventional needle irrigation. Forty extracted human mandibular first molar teeth with the isthmus between the mesial roots were selected, access cavities were prepared and distal roots were decoronated. All the mesial root specimens were mounted in acrylic, sectioned at the coronal, middle, and apical thirds, along with the resin block, and examined for debris in the canals and isthmus before the start of the procedure using a stereomicroscope and were mounted back in a custom-made jig. After determination of the working length, they were allocated to the following four different irrigant activation groups (n = 10): Group I-XP-endo Finisher; group II-EndoVac; group III-plastic finishing file; and group IV-standard needle irrigation. After biomechanical preparation (BMP) till F3, final agitation was done for debris removal with the respective agitating devices, and all the samples were examined under a stereomicroscope for the amount of debris in the canal after final agitation. Of all the irrigation devices used, the XP-endo Finisher and EV showed more debris removal when compared to other groups (p < 0.05). The plastic finishing file in continuous rotation was more efficient in cleaning debris compared with conventional needle irrigation (p < 0.05). The XP-endo Finisher and EV showed a significant difference in cleaning efficacy than the plastic finishing files. So, these can be used as adjunctive for agitating the final irrigant. The irrigant agitation devices promote the penetration of irrigants into the intricate root canal anatomy and increase their antibacterial and tissue-dissolving effectiveness thereby improving the success rate and treatment outcome.

A Cone Beam Computed Tomography Analysis of Bone Volume Variations of Extra-alveolar Region Based on Sex, Age, Vertical and Sagittal Facial Patterns.

The goal of this study is to measure mandibular buccal shelf (MBS) concerning angulation, bone volume, and cortical bone volume as well as bone depth and cortical bone depth of infrazygomatic crest (IZC) via cone beam computed tomography and evaluate the measurements according to sex, age, vertical, and sagittal facial types. This study collected lateral cephalograms and cone beam computed tomography scans from 100 individuals, which were used to observe angulation, bone and cortical bone volume entailing width and depth of MBS as well as the depth of IZC. FH-MP (mandibular plane angle) and A point-Nasion-B point were adopted to determine vertical and sagittal facial patterns respectively. Bone widths at 6mm and 11mm to cementoenamel junction (CEJ) and cortical bone width at 6mm to CEJ in MBS showed significant sex differences, while bone depths and cortical bone depths in IZC show significant age difference( P <0.05). Bone width and cortical bone width at 6mm to CEJ at the mesial root and 11mm to CEJ at both roots as well as angulations of MBS in the mandibular first molar region, bone depth and cortical bone depth at the maxillary first molar distal buccal root, and the proximity region were all correlated to FH-MP ( P <0.05). Short-faced individuals of Asian ethnicity tend to have greater bone width, greater projection in MBS, and greater bone depth in the posterior region of IZC. The optimal implant sites are 11mm apical to CEJ at the mandibular second molar distal root and 65° at the maxillary first molar mesial root.

Antimicrobial Efficacy of Different Irrigant Solutions Using a Novel Biofilm Model: An In Vitro Confocal Laser Scanning Microscopy Experiment.

To determine the ability of different irrigation solutions to biomechanically remove Enterococcus faecalis biofilm from a novel artificial root canal model during chemomechanical preparation. High resolution micro-computer-tomography scans of a mandibular molar's mesial root were used to produce 50 identical 3D-printed resin root canal models. These were cultured with E.faecalis over seven days to generate biofilm and subjected to chemomechanical preparation using: saline; 17% ethylenediaminetetraacetic acid (EDTA) or 2% sodium hypochlorite (NaOCl) alongside positive/negative controls (n = 10). Canals were prepared to 40/.06 taper, with 1 mL irrigation between instruments, followed by 5 mL penultimate rinse, 30 s ultrasonic activation and 5 mL final rinse. Residual biofilm volume (pixels) was determined following immunofluorescent staining and confocal-laser-scanning-microscopy imaging. Statistical comparisons were made using Kruskal-Wallis with post-hoc Dunn's tests (α ⟨0.05). In all canal thirds, the greatest biofilm removal was observed with NaOCl, followed by EDTA and saline. The latter had significantly higher E.faecalis counts than NaOCl and EDTA (P ⟨0.01). However, no statistical differences were found between EDTA and NaOCl or saline and positive controls (P ⟩0.05). Within limitations of this model, 17% EDTA was found to be as effective as 2% NaOCl at eradicating E.faecalis biofilm following chemomechanical preparation. Further investigations with multi-species biofilms are encouraged.

Effect of piezocision-assisted lower second molar protraction on periodontal tissues, alveolar bone height, and lower second molar root resorption.

To assess the effect of piezocision on periodontal tissues and alveolar bone height and to detect lower second molar root resorption in piezocision-assisted mandibular second molar protraction compared to no-piezocision molar protraction. Twenty-one subjects (four males, 17 females, aged 22.43 ± 2.83 years) who presented with bilateral extraction of lower first molars were included. The patients were divided into two groups; Group 1: Piezocision-assisted molar protraction (right or left side of subjects) in which piezocision was performed immediately before lower second molar protraction and, Group 2: No-piezocision molar protraction in which lower second molar protraction was not surgically assisted. Plaque index (PI), gingival index (GI), periodontal pocket depth (PPD), width of keratinized gingiva (WKG), gingival recession (GR), lower second molar mesial root resorption, alveolar bone height, and mandibular bone height were recorded at T1 (immediately before molar protraction) and at T2 (after second molar space closure). In the piezocision-assisted molar protraction group, significant changes were detected in the WKG (P < .001), GR (P < .05), and the mandibular bone height (P < .001). Compared to the no-piezocision group, piezocision-assisted molar protraction resulted in an increased WKG (P < .001) and less second molar mesial root resorption (P < .01). Piezocision does not have any detrimental effect on the periodontium and produces less root resorption.

The Evaluation of Debris and Smear Layer Generated by Three Rotary Instruments Neo NiTi, 2Shape and Revo_S: An Ex-vivo Scanning Electron Microscopic Study.

This study compared the cleaning effectiveness of NeoNiTi, 2Shape and Revo_S rotary instruments. Fifty mandibular molar mesial roots were selected with an angle of curvature less than 20 degrees divided into three groups (n=15). Five samples were selected as negative control group. In all three systems, the final file was 25, 6%. The score of debris and smear layer in three thirds (coronal, middle and apical) of the root canal walls were evaluated using scanning electron microscopic (SEM) magnification. The data were analyzed using the Kruskal Wallis and Mann Whitney U tests for intergroup comparison (P≤0.05) and Freidman and Wilcoxon signed-rank test was employed for intragroup comparison (P≤0.05). Residual debris of the 2Shape system in the apical region was significantly higher than the other two systems (P=0.039). Revo_S and 2Shape groups had significantly higher quantities of debris in the apical than the coronal region (P=0.029 and P=0.02, respectively). In the 2Shape group, the amount of mid-region debris was significantly higher (P=0.005) than the coronal. In inter-group comparison there was no significant difference in residual smear layer between the systems. In intra-group comparison in all three systems, the amount of smear layer in the coronal third was significantly higher than in the other two areas. (P=0.017, P<0.001 and P=0.032, respectively). 2Shape left the highest amount of debris in the apical region. The amount of debris in Revo_S and 2Shape groups in the apical region was significantly higher than in the coronal. The amount of smear layer in all three groups in the coronal area was higher than the middle and apical areas.

Ageing-related effects of dye penetration in the apical 5 mm mesiobuccal and mesial roots of molars.

This study examined how the tubular permeability in the apical 5 mm of mesial roots was affected by age, direction, distance from root apex, canal shape and canal number. Twenty mesiobuccal/mesial roots of maxillary/mandibular molars from three age groups (<30, 30-60, >60 years) were prepared. Maximal dye penetration in buccal, lingual, mesial and distal directions was measured at 1-mm segment depth and analysed statistically. The <30 years group, when comparing to the >60 years group, had significantly deeper dye penetration in buccal and lingual directions. The permeability in proximal directions was not affected by either age or canal number. In the >60 years group, neither direction, segment depth nor canal number significantly impacted the permeability. However, these parameters significantly impacted samples younger than 60 years. Effective removal of infected root canal dentine would depend on age and its related preferred direction, distance from root apex and canal number.

Shaping ability of different NiTi rotary systems during the preparation of printed mandibular molars.

This study aimed to evaluate the shaping ability of XP-endo Shaper, TruNatomy and EdgeFile X3 during the preparation of resin-printed mandibular molar mesial root canals. Thirty-three resin-based mandibular mesial roots with two canals, obtained from extracted tooth cone-beam computed tomography (CBCT) image and printed on a three-dimensional (3D) printer, were divided into three experimental groups according to the different nickel-titanium (NiTi) systems used for root canal preparation. The specimens were scanned using CBCT imaging before and after root canal preparation. Then images were registered using a dedicated software and changes in the canal area, volume, untouched canal surface and the maximum and minimum dentine wall wear were calculated. The XP-endo Shaper instruments showed improved shaping ability with lower untouched root canal surface and better preservation of root canal anatomy during the preparation of resin-printed mandibular mesial root canals compared with TruNatomy and EdgeFile X3 systems.

Guided endodontic treatment in a region of limited mouth opening: a case report of mandibular molar mesial root canals with dystrophic calcification

BackgroundThe endodontic treatment of calcified root canals in molars is a challenging and time-consuming procedure. Even with the aid of a surgical microscope, the risk of root perforation is high, especially in the furcation area. The purpose of this study is to report the Computer-Aided-Design and Manufacturing (CAD–CAM) workflow, the innovative strategies for the template ideation, and the guided endodontic treatment of a mandibular molar with dystrophic calcification in the mesial root canals.Case presentationA 58-year-old female patient, ASA I, was referred to endodontic treatment in the right first mandibular molar for prosthetic reasons. The mesiobuccal and mesiolingual canals appeared obliterated in the radiographic images. The absence of dental crown, tooth inclination, and the limited mouth opening of the region contributed to a poor visual reference of the tooth in the dental arch and the direction of the remaining lumens of the canals. Despite using surgical microscopy, the conventional technique led to the deviation of the mesiobuccal canal towards the furcation area. The obliteration of both mesial root canals was confirmed using the Cone Beam Computer Tomography. The clinical history associated with the tomography diagnosis was compatible with dystrophic calcifications in the pulp canals. The patient was submitted to an intra-oral scanning as well. The Digital Imaging and Communications in Medicine data (DICOM) were segmented. The Standard Tessellation Language (STL) files were processed following the CAD–CAM workflow, aiming to create two different endodontic templates with a new open design concept. The templates with open design allowed direct visualization of the operative field, irrigation, and dentin debris removal. The strategy of the guidance sleeves niche as half-cylinders allowed the drill insertion in a limited mouth opening region.ConclusionsThe digital planning and guided access permitted to overcome the case limitations and then re-establish the glide path following the original anatomy of the root canals. The guided endodontic represents a personalized technique that provides security, reduced risks of root perforation, and a significant decrease of the working time to access obliterated root canals even in the mesial root canal of mandibular molars, a region of limited mouth opening.

Japanese Maxillary First Molar Root Canal Morphology: An Ultrastructural Study Using Micro-Computed Tomography

The present study used ultra-high-resolution micro-computed tomography (CT) to clarify the classification of root canal morphologies and the incidence of accessory canals in the maxillary first molar mesiobuccal (MB) root. Aspects of the relationship with root canal reinfection during or after molar endodontic treatment were also investigated. Molar three-dimensional structure, pulp cavity, and accessory canals were examined on micro-CT images of 100 Japanese maxillary first molars from the collection at the Department of Anatomy, Tokyo Dental College. The most common Vertucci’s classification of the main root canal of the Japanese maxillary first molar mesial root canal was Type I, followed by Type V. Accessory canal incidence was 75.0%, which was higher than previously reported; however, the majority of such canals were within the apical 3 mm. Many accessory canals were observed even with the single canals of Type I, suggesting that the existence of accessory canals should always be considered even if diagnostic imaging clearly shows a Type I classification.

Shaping ability of modern Nickel-Titanium rotary systems on the preparation of printed mandibular molars.

This study aimed to evaluate the shaping ability of TruNatomy (Dentsply Maillefer, Ballaigues, Switzerland), VDW.ROTATE (VDW GmbH, Munich, Germany) and ProTaper Gold (Dentsply Maillefer, Ballaigues, Switzerland) during the preparation of resin-printed mandibular molar mesial root canals. Thirty-three printed resin-based mandibular mesial roots with two canals were obtained from extract tooth cone-beam computed tomography (CBCT) image. The printed teeth were divided into three groups (n = 11) according to the system used for root canal preparation: TruNatomy, VDW.ROTATE, and ProTaper Gold. The specimens were scanned using CBCT imaging before and after root canal preparation. Then images were registered using a dedicated software and changes in the canal area, volume, untouched canal surface, and the maximum and minimum dentin wall wear were calculated. Data were statistically analyzed using Shapiro-Wilk for normality, one-way ANOVA, and Tukey or Kruskal-Wallis H tests with alpha set at 5%. No differences were observed for changes in the canal area, volume, untouched canal surface area, and minimum dentine wall wear parameters for the whole canal length (P > 0.05). The mean of untouched canal surface area for the TruNatomy, VDW.ROTATE, and ProTaper Gold was 40%, 44%, and 44%, respectively. The maximum dentine wall wear was significantly lower in the ProTaper Gold group than in the TruNatomy and VDW.ROTATE groups (P < 0.05). TruNatomy, VDW.ROTATE, and ProTaper Gold systems showed similar shaping ability in printed resin-based mandibular mesial roots without clinically significant errors. A large amount of untouched canal surface area was observed for all systems.

Comparative Evaluation of Dentinal Microcrack Formation before and after Root Canal Preparation Using Rotary, Reciprocating, and Adaptive Instruments at Different Working Lengths—A Micro–computed Tomographic Study

IntroductionThis study aimed to compare root dentinal microcrack formation after root canal shaping using rotary, reciprocating, and adaptive instruments at different working lengths using micro–computed tomographic imaging. MethodsOne hundred eighty extracted mature mandibular molar mesial roots with 2 separate canals were selected. The mesial roots were resected at the cementoenamel junction and randomly divided into 4 groups (n = 45) based on the nickel-titanium file system used: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Gold (Dentsply Maillefer), Twisted File Adaptive (SybronEndo, Orange, CA), and Reciproc Blue (VDW, Munich, Germany). Each of the 4 groups were then subdivided into 3 groups (n = 15) depending on the working length used for root canal preparation (ie, instrumentation 1 mm short, flush, and 1 mm beyond the major apical foramen). The roots were imaged with micro–computed tomographic scanning before and after root canal preparation. The cross-sectional images generated were screened to detect the presence of new microcracks. ResultsThe ProTaper Universal system significantly increased the number of postinstrumentation microcracks at all working lengths (P ≤ .05). No significant increase (P > .05) in postinstrumentation microcracks was observed in the ProTaper Gold, Twisted File Adaptive, or Reciproc Blue groups. ConclusionsRotary instrumentation induced a higher number of dentinal microcracks compared with reciprocating and adaptive instruments. Instrumentation at different working lengths did not significantly influence the formation of dentinal microcracks.

Scanning electron microscopy analysis of conventional and controlled-memory nickel titanium files before and after multi-uses in root canals.

The current study aimed to examine changes in the physical properties of conventional and CM nickel-titanium instruments after repeated clinical use, disinfection-sterilization processes, using scanning electron microscopy (SEM). Sixty extracted mandibular molar mesial roots were used in this ex vivo study. The 60 teeth underwent final apical shaping (#25/.06) by the Revo-S SU (Revo-S Group: #25/.06; Micromega; n=10) and Hyflex CM (Hyflex CM group: #25/.06; Coltene-Whaledent; n=10) groups. One instrument of each group was used to shape six different teeth (Revo-S SU in 3 MB and 3 ML canals, and Hyflex CM in 3 MB and 3 ML canals), sequentially. The physical changes evident on the surfaces of the files after sequential use and sterilization processes were analyzed by SEM after the first, third, and sixth use. The first SEM examination was performed immediately after removal from the packages. Following first SEM examination, the files were sterilized before the first use as would be customary in practice. Qualitative evaluations were made by two evaluators, according to the following criteria: tip deformation, cutting edge deformation, debris, and microfracture. Revo-S showed a significant difference in cutting edge deformation, tip deformation, and microcrack formation, as compared to Hyflex CM. There was no significant difference between the groups in debris with the increasing number of uses. In this study, Hyflex CM (CM nickel-titanium) files showed better performance in terms of deformation and microcrack formation as the number of uses increased than did Revo-S (conventional nickel-titanium) files.

The influence of age, sex, and tooth type on the anatomical relationship between tooth roots and the mandibular canal.

PurposeCone-beam computed tomography (CBCT) reconstructions were analysed to elucidate factors affecting the anatomical relationship between tooth roots and the mandibular canal(MC).Materials and MethodsImages of 300 volumetric tomography scans of patients aged between 20 and 79 years old (167 women and 133 men) were analysed. The mean distances between 2,053 dental root apices and the internal border of the MC were obtained by measuring the horizontal and vertical distances on coronal CBCT images. The actual distance was then calculated mathematically with the Pythagorean formula. The statistical significance of differences between men and women was assessed using the Mann-Whitney test. Correlations with patient age were evaluated with the Spearman rank correlation coefficient.ResultsThe mean distances ranged from 2.17 mm, for single right third molar roots in women, to 8.02 mm for single left third molar mesiolingual roots in men. The mean distances measured for the mandibular right second molar mesial roots and the right second premolar roots were larger in men than in women. Age showed a significant positive correlation with the measured distances for mesial and distal roots of the first and second molar on both sides and the right third molar, mesiolingual roots of the left third molar, and single roots of the right third molar.ConclusionThe root-to-mandibular canal distance depended on age and the type of tooth. In 2 root types, this distance was impacted by sex.

Zygomatic-maxillary cortical bone thickness in hyper, normo and hypodivergent patients

ABSTRACTObjective: The aim of this study was to evaluate the thickness of the zygomatic-maxillary cortical bone using computed tomography in different skeletal patterns. Methods: A total of 54 patients of both sexes, divided into three groups according to the vertical skeletal pattern, were evaluated for cortical bone thickness of the anterior slope of the zygomatic process of the maxilla, using cone beam computed tomography. Measurements were made at 2mm, 4mm, 6mm, 8mm and 10mm above from first molar mesial root apex. Vertical skeletal pattern was determined by Frankfurt mandibular angle (FMA).Results: The hyperdivergent pattern had the lowest cortical thickness value, nevertheless, no patient in the hyperdivergent group presented cortical thickness exceeding 2mm, and no patient in the hypodivergent group presented cortical thickness less than 1mm. However, the correlation between cortical thickness and mandibular plane angle was weak and not significant. Conclusion: Although higher prevalence of thick cortical was observed in the hypodivergent patients, and thin cortical groups in the hyperdivergent group, the vertical skeletal pattern could not be used as determinant of the zygomatic-maxillary cortical thickness.

Prevalence of middle mesial canal in mandibular first molars using cone-beam computed tomography technique

The purpose of this study was to evaluate the prevalence of middle mesial canal in mandibular first molars using cone-beam computed tomography (CBCT). In this descriptive study, a total of 768 radiographs of mandibular first molars, 384 for males and 384 for females, taken at a private radiology center in Isfahan, were assessed for the presence of middle mesial canal based on the gender of the patients. All samples had been prepared by one CBCT machine. The images were evaluated by endodontists and radiologists. Then, the morphology of first molar mesial root canals was assessed by Vertucci classification, and the obtained results were analyzed by SPSS software using a Chi-square test. The comparison was considered statistically significant at P < 0.05. Twenty-four samples (3.13%) had a middle mesial canal. The prevalence rates of the middle mesial canal in the females and males were found to be 9 and 15 (2.35% vs. 3.92%), respectively, indicating no statistically significant difference (P = 0.21). Of 24 teeth with middle mesial canal, 17 samples (70.8%) were of Type XII and 7 samples (29.2%) were of Type VIII. There was no statistically significant difference between genders with regard to the prevalence of different types of middle mesial canals (P = 0.19). The prevalence of the middle mesial canal was rather low in this study, and it is necessary to detect additional canals in the patients under root canal treatment.

Surface integrity of root ends following apical resection with targeted trephine burs

Aim: Targeted endodontic microsurgery may be performed utilizing trephine burs. The purpose of this study was to determine if guided resection using trephine burs produces cracks or fractures within the root. Methodology: Twenty maxillary anterior and twenty mandibular molar mesial roots from extracted teeth were cleaned, shaped, and obturated. Roots were resected with either targeted trephine burs or multipurpose burs. Resected root ends were analyzed using light microscopy with a fluorescent filter and a dental operating microscope. Teeth were graded based on the presence, extent, and location of cracks. Results: One (10%) anterior trephine-resected root demonstrated cracks, while three (30%) anterior multipurpose bur-resected roots had cracks. These findings were not statistically different (P=0.264, Chi-square=1.25). No molar teeth had detectable cracks. There was no significant difference between the groups with regards to crack formation. Conclusions: Analysis of the samples supports the use of trephine burs in targeted endodontic microsurgery.

Anatomical analysis of mandibular posterior teeth for endodontic microsurgery: a cone-beam computed tomographic evaluation.

The purpose of this study was to analyze the anatomical structures relevant for endodontic microsurgery in the mandibular posterior teeth using a cone-beam computed tomography (CBCT). A total of 963 mandibular posterior teeth were analyzed in CBCT scans from 133 patients. The buccolingual and mesiodistal dimensions of the root and the buccal bone thickness overlying the root were measured at the site of root resection (apical 3 mm). At this location, the relationship between the buccal cortical bone and root was classified into three types (separated, contact, and exposed), and the distance from the root apex to the mandibular canal was measured. The thickest buccolingual dimension of the roots was found in the mesial roots of first molars, at 5.59 ± 0.97 mm. The buccal bone thickness overlying the root became thicker in posterior tooth locations. In the first premolar and first molar mesial root, contact was the most common type of relationship between the buccal cortical bone and root. As the position of the teeth became more posterior, the distance from the apex to the mandibular canal became shorter. As the position of the teeth became more posterior, the buccal bone thickness increased and the distance to the mandibular canal became closer; therefore, particular attention is required for posterior teeth. The first premolar and the first molar mesial root are often in contact with the buccal cortical bone, which may allow infections to spread to the buccal structure more easily and negatively affect for post-surgical healing. When planning and performing endodontic microsurgery, understanding the anatomical structure of the surgical site will help minimize tissue damage and reduce complications.