Anatomical relationship of maxillary posterior teeth with the sinus floor and buccal cortex

This study aimed to evaluate the possibility of root fenestration or oroantral communication by evaluating the distance from root apex to the sinus floor and buccal cortex in maxillary posterior teeth using cone‐beam computed tomography (CBCT) images. The study included 2182 roots of the maxillary posterior teeth from 219 patients after reviewing CBCT images of 462 patients according to the location of roots by two endodontists. The distances from each root apex to the maxillary sinus floor and buccal and palatal cortices were evaluated according to sex and age, and the mean values were compared by one‐way analysis of variance and Mann–Whitney U‐test. The distance between root apex and maxillary sinus floor was the greatest in maxillary first premolars and shortest in the mesio‐buccal roots of maxillary second molars. The distances from root apex to the buccal and palatal cortical bones were significantly greater in male patients than those in female patients (P < 0·05). The palatal roots of maxillary first molars exhibited the highest incidence as well as the greatest mean length (1·96 mm) of protrusion into the maxillary sinus. The distance from root apex to the sinus floor was found to increase with age, except in case of maxillary second premolars. Understanding the relationship of maxillary posterior teeth with the sinus floor and buccal cortex could provide clinicians valuable information to help reduce iatrogenic damage.     

上颌窦底与上颌磨牙牙根关系的锥形束CT研究

目的：应用锥形束CT分析上颌窦底与上颌磨牙牙根的关系,为临床治疗提供参考。方法：收集具备上颌后部锥形束CT扫描数据的患者资料,应用CT配套软件观察上颌窦底与上颌磨牙牙根的关系并测量上颌磨牙牙根与上颌窦底间距离。结果：共收集40例,男26名,女14名,平均年龄35.5岁（19～55岁）。12例牙根根尖与上颌窦底在同一水平;16例牙根根尖水平高于上颌窦底水平,平均距离为（3.62±0.52）mm;12例牙根根尖水平低于上颌窦底水平,平均距离（3.16±0.42）mm。在距离上颌窦底最近的牙根方面,上颌第一磨牙腭根最为多见（20/40）。结论：锥形束CT在判断上颌窦底与上颌磨牙牙根关系方面有较高应用价值。上颌窦底与上颌磨牙牙根关系密切,其中,与第一磨牙腭根关系最为密切,临床治疗中应预防上颌窦穿孔或上颌窦炎的发生。     

CBCT分析上颌磨牙牙根及其牙槽嵴顶与上颌窦底壁的位置关系

目的 利用CBCT分析上颌第一、第二磨牙各牙根根尖及其牙槽嵴顶与上颌窦底壁位置关系,为临床诊断和治疗提供可靠的参考依据。方法 选取大连医科大学口腔医学院附属口腔医院锥形束CT(CBCT)数据库中初诊180例,分为6～12岁、13～18岁和19～35岁三组,每组各60例。利用CBCT测量上颌第一、第二磨牙各牙根根尖与上颌窦底壁的距离、上颌磨牙牙槽嵴顶与上颌窦底壁距离,分别进行左右两侧与性别差异对比,记录上颌第一、第二磨牙各牙根根尖与上颌窦底壁的位置关系分型,并进行统计学分析。结果 上颌第一磨牙在6～12岁组距离上颌窦底壁平均距离最短的为近颊根(1.21±3.09)mm,13～18岁组根尖均在上颌窦内,19～35岁组的腭根为(0.41±2.73)mm;上颌第二磨牙在13～18岁组与19～35岁组距离上颌窦底壁平均距离最短的均为近颊根,为(0.36±2.37)mm和(0.43±2.21)mm。随着年龄增长,牙槽嵴顶至上颌窦底壁的平均距离逐渐降低(P<0.05)。水平关系中,上颌第一磨牙13～18岁组、19～35岁组牙根根尖至根分叉区域观察到上颌窦最常见;垂直关系中,6～12岁组与19～35岁组中第一磨牙、13～18岁组的第二磨牙三个牙根都没有接触上颌窦底壁的情况最常见。结论 上颌第一、第二磨牙与上颌窦底壁联系密切,建议在开展临床治疗前应用CBCT,对于上颌后区解剖位置关系的分析和降低上颌窦并发症发生率具有积极意义。     

Proximity of Vascular Bone Channel in the Lateral Sinus Wall to Root Apices of Maxillary First Molars: A Cone-beam Computed Tomographic Analysis

IntroductionApical surgery is frequently indicated in maxillary first molars. Occasionally, a vascular anastomosis in the lateral maxillary sinus wall can be observed during surgery. The aim of this study was to examine the distance between the vascular bone channel (VBC) and the root apices of maxillary first molars using cone-beam computed tomographic imaging.MethodsCone-beam computed tomographic images of 104 maxillary first molars were oriented in the coronal plane to evaluate the distance between the roots and the VBC. The measurements were only recorded in relation to the buccal roots. In addition, demographic parameters and further measurements such as the diameter of the VBC and the proximity to the periapical pathology were evaluated.ResultsA total of 210 VBCs were assessed. The mean distance from the VBC to the apices of the buccal roots of the maxillary first molars was 6.18 mm ± 3.84 mm. The VBC was mostly located intrasinusally (74.3%) and only rarely superficially (0.5%). The diameter of the VBC was on average 0.88 ± 0.32 mm.ConclusionsIn this study, the VBC was usually found closer to the mesiobuccal than to the distobuccal root apex. During preparation of the access window, the existence of the VBC should be kept in mind because the mesiobuccal roots of maxillary first molars undergo apical surgery to the buccally positioned roots only.     

Roots of the maxillary first and second molars in horizontal relation to alveolar cortical plates and maxillary sinus: computed tomography assessment for infection spread

The purposes of this study were to investigate the horizontal relationship of the roots of maxillary molars with the cortical plates and the maxillary sinus and to investigate the influence of these relationships on the spread of odontogenic infection. Computed tomography images of 120 control subjects and 49 patients with infection originating in the maxillary first or second molar were investigated. In the control group, more than 60% of the first molar roots contacted both palatal and buccal cortical plates (type A), while such contact was not seen in more than 60% of second molars. The floor of maxillary sinus was most frequently observed at the level between the bifurcation and apices of roots in both first and second molars. In patients with infection, cortical changes were more frequently seen on the buccal side than on the palatal side, and 80% of patients with buccal cortical change showed the position in which the buccal roots were close to the buccal cortical plate. Mucosal thickening of the maxillary sinus was found in 87.8%. The buccopalatal spread of odontogenic infection originating in the maxillary first and second molars was influenced by the horizontal root position in relation to the cortices.     

Targeted Endodontic Microsurgery: Implications of the Greater Palatine Artery

IntroductionTargeted Endodontic Microsurgery (TEMS) combines trephine burs and 3D-printed guides to make flapless maxillary palatal root-end surgery possible. This study assessed the location of the greater palatine artery (GPA), the relationship of the GPA to maxillary molar root ends, and the feasibility of flapless palatal-approach TEMS.MethodsThree endodontists analyzed 250 cone-beam computed tomographic images of maxillary molars for (1) transition morphology between the hard palate and the alveolar process adjacent to first and second molars as an indication of the most likely location of the GPA, (2) the superior-inferior relationship between the GPA and root ends, and (3) the feasibility of palatal-approach TEMS.ResultsPalatal transition morphology included 20% Spine, 72% Bridge, and 8% Smooth. GPA position as related to palatal root ends was classified as 34% superior, 40% adjacent, and 21% inferior. Five percent of classifications were undefined. TEMS was deemed feasible for 47% of maxillary first molars and 52% of second molars, and was significantly more feasible with GPAs superior to palatal root ends. Reasons for infeasibility included GPA proximity and unfavorable resection angle or level. Maxillary first molar palatal roots were 11.13 ± 2.68 mm from the greater palatine foramen (GPF) and 2.37 ± 1.46 mm from the GPA. Second molar palatal roots were 4.94 ± 2.55 mm from the GPF and 2.53 ± 1.77 mm from the GPA.ConclusionsPalatal transition morphology and GPA position adjacent to maxillary molars, as manifested in cone-beam computed tomographic coronal views, suggested maxillary palatal root TEMS could be accomplished with a 2-mm safety margin in 47% of first molars and 52% of second molars. Historical paradigms that do not consider flapless palatal surgical approaches may need to be revised.     

The Effect of the Anatomic Variables on the Success Rate of Anesthesia in Maxillary Molars with Irreversible Pulpitis

IntroductionObtaining anesthesia of teeth with irreversible pulpitis is 1 of the most challenging issues in endodontic practice. The aim of this study was to evaluate the effect of anatomic variables on the success rate of anesthesia in maxillary molars with irreversible pulpitis.MethodsPatients who had maxillary molars with irreversible pulpitis and who had already had a cone-beam computed tomographic (CBCT) scan performed were included in this study. After infiltration injection of an anesthetic solution, the success rate of anesthesia was recorded by asking the patients to rate their pain during access cavity preparation and root canal instrumentation as well as their need for a supplementary injection during the treatment. The distance of the palatal root to the buccal cortical plate was calculated using the Romexis Viewer (Planmeca, Helsinki, Finland) measuring tools in both the axial and coronal views. Data were analyzed by chi-square and t tests as well as receiver operating characteristic curve analysis.ResultsForty-seven maxillary first and second molar teeth were eligible to be included in this study. The overall success rate of anesthesia was 63.80%. The palatal roots that had their apex located more than 12.34 mm from the buccal cortical plate in the axial view, and 12.46 mm in the coronal view had a higher chance of anesthesia failure compared with the teeth with smaller distances. The presence of the maxillary sinus between the cortical plate and roots had no significant impact on the efficacy of anesthesia (P > .05).ConclusionsThe potential of anesthesia failure during the treatment of irreversible pulpitis in maxillary molars with a divergent palatal root is significantly higher than in teeth with shorter distances from the palatal root apex to the buccal cortical plate. If a patient already had a CBCT scan done for other reasons or the CBCT is available in his or her records, a dental practitioner can use it to predict anesthesia success for maxillary molars with irreversible pulpitis.     

Buccal bone plate thickness of the Asian people

Distances from the apex to the buccal bone plate were measured on the computed tomography (CT) images of 1806 teeth from 66 patients, using an image analyzer program (Image-Pro Plus, Ver. 4.0, Media Cybernetics). In the mandible, the mean distance from the distal apex of the mandibular second molar to the buccal bone plate was the largest distance measured, at 8.51 mm, followed by distance from the mesial root to the buccal bone (7.34 mm). In the mandibular first molar, the mean distal and mesial bone thicknesses were 5.18 mm and 4.09 mm, respectively. However, when there were two distal roots, the distance of the disto-lingual root to the buccal plate was found to be 9.52 mm, which constitutes the greatest measured thickness. In the maxillary buccal roots, the distances from the mesio-buccal and disto-buccal root of the second molar to the buccal bone plate were the largest, at 4.63 mm and 3.61 mm, respectively. The average distances from the palatal apex of the maxillary first and second molars to the buccal bone plate were 10.69 mm and 10.17 mm, respectively, while, from the palatal bone plate, average distances of 3.15 mm and 3.08 mm were measured. Special considerations, such as bony lid approach, lingual approach, or intentional replantation may be required, especially when a patient has a surgical need in the second molars and the disto-lingual root of the mandibular first molar, or in the palatal root of the maxillary molars.     

A Rare Root Canal Configuration of Bilateral Maxillary First Molar with 7 Root Canals Diagnosed Using Cone-beam Computed Tomographic Scanning: A Case Report

Introduction

The complexity of the root canal system of maxillary molars presents a constant challenge in the diagnosis and treatment of these teeth. This case report describes the importance of a surgical operating microscope and cone-beam computed tomographic (CBCT) imaging.

Methods

Root canal treatment of a left maxillary first molar with 3 roots and 7 canals was successfully performed. Seven canals were identified with the help of a surgical operating microscope and CBCT imaging. CBCT images also confirmed the 3 roots and 7 canals in the right maxillary first molar.

Results

CBCT images confirmed a type IV canal pattern in the distal and palatal root, whereas the mesial root had a type VIII canal pattern.

Conclusions

The use of a surgical operating microscope and CBCT imaging helps the clinician to diagnose unusual anatomy of a tooth and facilitate successful endodontic treatment.     

Anatomic Analysis of Palatal Roots of Maxillary Molars Using Micro–computed Tomography

IntroductionThe morphology of the palatal root of maxillary first and second molars was analyzed and compared using micro–computed tomographic scanning.MethodsForty-seven extracted maxillary molars were scanned with a micro–computed tomographic device to analyze the palatal radicular dentin dimensions, canal working width, root length, canal curvature, lateral canals, and apical constriction anatomy. Quantitative data were analyzed with mean and standard deviation for first and second molars, respectively. Comparison was made between first and second molars using an unpaired t test.ResultsThe 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, correlating approximately to the level of the cementoenamel junction and pulpal floor. Significant canal curvature was present. These findings suggest the need for conservative coronal flaring and instrumentation.ConclusionsThe 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. A minimum master apical file size of 40 is recommended based on preoperative working widths in the apical 0.5–1.0 mm. A root-end resection of 3.5 mm would remove a greater majority of lateral canals.     

Evaluation of Root Canal Configuration of Maxillary Molars in a Brazilian Population Using Cone-beam Computed Tomographic Imaging: An In Vivo Study

Introduction

The aim of this study was to analyze and characterize root canal morphology of maxillary molars of the Brazilian population using cone-beam computed tomographic (CBCT) imaging.

Methods

Patients referred for a CBCT radiographic examination for accurate diagnosis and treatment planning were enrolled in the study. A total of 620 healthy, untreated, fully developed maxillary first and second molars were included (314 first molars and 306 second molars). The following observations were recorded: (1) number of roots and their morphology, (2) number of canals per root, (3) fused roots, and (4) primary variations in the morphology of the root canal systems.

Results

First and second molars showed a higher prevalence of 3 separate roots, mesiobuccal, distobuccal, and palatal, with 1 canal in each root (52.87% and 45.09%, respectively). Two canals in the mesiobuccal roots represented 42.63% of teeth, whereas mesiobuccal roots of second molars presented 2 canals in 34.32%. The most common anatomic variation in the maxillary first molar was related to the root canal configuration of the mesiobuccal root, whereas the root canal system of the maxillary second molar teeth showed more anatomic variables.

Conclusions

Mesiobuccal roots of maxillary molar teeth had more variation in their canal system than the distobuccal or palatal roots. The root canal configuration of the maxillary second molars was more variable than the first molars in a Brazilian population. CBCT imaging is a clinically useful tool for endodontic diagnosis and treatment planning.     

锥形束CT分析中国人群上颌后牙区牙槽骨及牙根与上颌窦位置关系的研究

［摘要］ 目的 利用锥形束CT三维成像分析上颌后牙区牙槽骨高度以及牙根与上颌窦底位置关系,为临床诊断和治疗提供可靠的参考依据。方法 选取500例患者的锥形束CT影像资料,测量上颌前磨牙和磨牙的牙槽骨高度、牙根至上颌窦底距离、磨牙牙根与上颌窦的位置关系（垂直和水平关系）,按照牙位和年龄将这些数据分组,分析在不同牙位和年龄段的差异。结果 上颌前磨牙的牙槽骨高度分别为（11.31±7.39）和（9.52±7.98）mm,显著高于上颌磨牙区,随着年龄的增长牙槽骨高度降低。上颌第二磨牙近颊根至上颌窦底距离最短,其平均值为（1.73±3.63）mm;第一前磨牙牙根至上颌窦底的平均值为（9.53±5.79）mm,至上颌窦底距离最长,随着年龄的增长,牙根与上颌窦底间距离变短。在牙根与上颌窦的垂直关系中,三个牙根均不与上颌窦下壁接触的情况显著高于其他分类;水平关系中,在根尖至根分叉水平观察到上颌窦最为常见;随诊年龄的增长牙根与上颌窦的关系更加密切。结论 不同年龄和牙位牙根与上颌窦的关系差异较大,利用锥形束CT可精确分析上颌后牙区解剖结构,制定个性化治疗方案,降低医源性问题的发生。     

The root and root canal anatomy of maxillary molars in a Chinese population

Abstract The purpose of this investigation was to study the prevalence of fused roots, C-shaped roots, C-shaped root canal orifices and C-shaped root canals in the maxillary molars of a Chinese population. A total of 305 first molars and 309 second molars were collected in Taiwan. The teeth were demineralized and placed in methyl salicylate to make them transparent. Root fusion was examined and the pulp chamber floor was checked for C-shaped orifices. Chinese ink was then injected into the root canal system to demonstrate possible C-shaped canals. The maxillary first molars had the palatal root fused with the mesiobuccal root in 0.3% of the cases, and with the distobuccal root in 2.0%. Teeth with C-shaped roots existed in only 0.3% of maxillary first molars, while 6.2% of the maxillary first molars and 40.1% of the maxillary second molars had fused roots. The maxillary second molars had the palatal root fused with the mesiobuccal root in 18.1% and with the distobuccal root in 2.6%; the palatal root was fused with the mesiobuccal and distobuccal root in 8.1% of the material. The maxillary second molars had a C-shaped root in 4.5% and C-shaped root canal orifices with C-shaped root canals in 4.9% of the cases. Fused roots or incompletely separated roots are common in the maxillary second molars amongst Chinese people, while C-shaped roots and root canals in maxillary molars are not frequently seen.     

Maxillary Molars With Morphologic Variations of the Palatal Root Canals: A Report of Four Cases

IntroductionThe purpose of this article was to show the importance of the knowledge of the anatomy of root canals. Unusual root and root canal morphologies associated with both buccal roots of upper molars have been recorded in several studies in the literature. However, scientific information focusing on variations of the palatal root is rare.MethodsIn this report, four cases are presented involving the root canal treatment of maxillary first and second molars with unusual morphologic configurations of the palatal root canals.ResultsDuring root canal treatment, type IV and V configurations as defined by Vertucci of the palatal canals of two first and two second maxillary molars were identified. After mechanical instrumentation, the canals were obturated. Radiologic and clinical re-evaluation showed no signs of inflammation.ConclusionsThis report describes and discusses the possibility of different root and canal variations of the maxillary molars from a clinical point of view. Anatomic variations can occur in any tooth, and palatal roots of maxillary first and second molars are no exception. Therefore, careful examination of radiographs and internal anatomy of teeth is essential.     

Unusual root canal anatomy in maxillary second molars: two case reports

The aim of this clinical report is to describe the unusual root canal anatomy of 2 maxillary second molars with 2 separated palatal roots and the endodontic treatment procedures for those teeth. In these presented cases, microscopy was useful to identify distopalatal orifice. Radiographic interpretation was difficult owing to the overlap of the buccal and secondary palatal roots.     

A computed tomographic study of the distances between the maxillary sinus floor and the apices of the maxillary posterior teeth.

The mean distance between the apices of the maxillary posterior teeth and the floor of the maxillary sinus was measured from computed tomographic display data from 12 autopsy specimens and 38 human subjects. The distance from these apices to the adjacent lateral bony surfaces was also measured. The apex of the mesiobuccal root of the maxillary second molar was closest to the sinus floor (mean 1.97 mm) but farthest from the buccal bony surface (mean 4.45 mm). The apex of the buccal root of the maxillary first premolar was closest to the adjacent lateral bony surface (mean 1.63 mm) but farthest from the floor of the sinus (mean 7.05 mm).     

Vestibular surgical access to the palatine root of the superior first molar: "low-dose cone-beam" CT analysis of the pathway and its anatomic variations

Apicoectomy of the superior first molar palatine root until recently involved relatively destructive and laborious surgery because of the palatal access route, which not only necessitates an extensive flap, but also the readying of procedures required to deal with a possible hemorrhage from the palatine artery. With the advent of operative microscopy, endodontic surgery has become more precise and less invasive and its technical potential has increased; a possible innovative surgical technique may entail vestibular root access. The possibility of using low-dose, low-cost computed tomography (CT) dedicated to the jaw to obtain anatomic information to plan apicoectomy via the vestibular approach was evaluated; 31 patients were referred to CT with the NewTom apparatus. In 43 superior first molars, the mean distance of the palatine root from the external vestibular cortex was measured, and the frequency that the maxillary sinus lateral recess lay between the roots was determined. The mean root apex-vestibular cortex distance was 9.73 mm. In 25% of cases the maxillary sinus recessus lay between vestibular and palatine roots. CT may play an important role in optimizing palatine root apicoectomy through vestibular access, with regard to precision and preventing complications, with relatively low biological and economic cost, also possibly contributing to the affirmation of this new surgical procedure.     

Periodontal surgery in furcation-involved maxillary molars revisited—an introduction of guidelines for comprehensive treatment

Maxillary molars with interradicular loss of periodontal tissue have an increased risk of additional attachment loss with an impaired long-term prognosis. Since accurate clinical analysis of furcation involvement is not feasible due to limited access, morphological variations and measurement errors, additional diagnostics, e.g., with cone-beam computed tomography, may be required. Surgical treatment options have graduated from a less invasive approach, i.e., keeping as much periodontal attachment as possible, to a more invasive approach: (1) open flap debridement with/without gingivectomy or apically repositioned flap and/or tunnelling; (2) root separation; (3) amputation/trisection of a root (with/without root separation or tunnel preparation); (4) amputation/trisection of two roots; and (5) extraction of the entire tooth. Tunnelling is indicated when the degree of root separation allows for opening of the interradicular region. Alternatively, root separation is performed particularly in root-canal treated teeth with reduced coronal tooth substance requiring crown restorations. As soon as the attachment of one or two roots in maxillary molars is severely reduced, root removal is indicated and performed either as amputation or trisection including the corresponding part of the clinical crown. While the indication for regenerative measures in maxillary molars with furcation involvement is very limited, extraction and replacement with implants is restricted, particularly in sites requiring complex alveolar ridge augmentation and sinus elevation. A systematic approach for decision making in furcation-involved maxillary molars is described in this overview, including what constitutes accurate diagnosis and what indications there are for the different surgical periodontal treatment options.     

Clinically Relevant Dimensions of 3-rooted Maxillary Premolars Obtained Via High-resolution Computed Tomography

Introduction

This study aimed to characterize the dimensions of a selection of 3-rooted maxillary premolars through high-resolution computed tomographic analysis considering measures of clinical interest for root canal treatment, such as root wall thickness, canal diameters, and distances between 2 canals in fused roots and between the root apex and foramen.

Methods

Fifteen 3-rooted human maxillary premolars extracted for therapeutic reasons were individually scanned using a high-resolution desktop high-resolution computed tomographic system. Starting from the apical foramen, the selected cross-sectional images corresponding to each millimeter of the roots were evaluated. Measures of clinical interest were determined using Image J software (version 1.41; National Institutes of Health, Bethesda, MD).

Results

Root wall thickness as thin as 0.4 and 0.6 mm was detected in the apical portion of buccal and palatal roots, respectively. In the cervical portion, buccal roots had narrower root walls (0.817–1.670 mm) compared with palatal roots (1.361–2.720 mm). In all thirds, the palatal canal was wider compared with the mesiobuccal and distobuccal canals. In the buccopalatal direction, all roots had thicker root walls toward the furcation, whereas in the mesiodistal direction the mesiobuccal and distobuccal roots had the thinnest walls along their distal and mesial aspects, respectively. Both buccal canals revealed dentin apposition 2 mm from the canal orifice, resulting in cervical constriction. Generally, the distance between the root apex and the foramen was greater in distobuccal roots in comparison with the others with a tendency for foramina to be eccentric.

Conclusions

Three-rooted premolars are a clinical challenge not just because of their low frequency and difficulties regarding diagnosis and root canals access but also because of their fragile roots. These phenomena are critical in terms of the amount of dentin removed during the preparation of root canals and during post space preparation.