Root Canal System Variation in Mandibular Second Molar: Middle-Mesial Canal

Middle-mesial canals in mandibular molars are present in the population depending on age, sex and ethnicity. However, limited literature alludes to its prevalence. Troughing procedures may enhance identification, cleaning and shaping. This case report expresses the recognition and management of middle-mesial canal in a mandibular second molar of 24 years old Hispanic-Latino male.

Root canal morphology and configuration of 123 maxillary second molars by means of micro-CT

The aim of this study was to investigate the root canal configuration, accessory canals and number of main foramina of 123 maxillary second molars by means of micro-computed tomography. The teeth were scanned and reproduced with 3D software imaging. The root canal configuration and number of main foramina were evaluated by means of a four-digit system. The morphological complexity of human maxillary second molars is depicted by the number of accessory and connecting canals. The most frequently observed 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%). A 1-1-1/1 configuration was observed in 93.5% and in 96.7% in the distobuccal and palatal roots, respectively. The MB1 root canal had one accessory canal(18.7%), and 8.9% of the MB2 root canal had one or two accessory canals. The distobuccal(11.3%) and palatal(14.6%) root canals had at least one accessory canal, and connecting canals were observed in16.3% of mesiobuccal roots. The MB1, MB2, distobuccal and palatal root canals had one main foramen in 99.2%, 43.1%,98.4% and 99.2% of samples, respectively. In the mesiobuccal root, one accessory foramen was detected in 14.6%, two were detected in 7.3%, and three were detected in 5.7%. The distobuccal root showed one or two accessory foramina in 9.1% of samples. The root canal configuration of maxillary second molars is quite heterogeneous; the mesiobuccal root has predominantly two root canal entrances(58.4%, 1 in 41.1%) with one main foramen(54.4%). Two main foramina were observed in 43.0%. Morphological variations, connecting and accessory canals were observed in all apical thirds.

Successful individualized endodontic treatment of severely curved root canals in a mandibular second molar:A case report

BACKGROUND The incidence rate of severely curved root canals in mandibular molars is low,and the root canal treatment of mandibular molars with this aberrant canal anatomy may be technically challenging.CASE SUMMARY A 26-year-old Chinese female patient presented with intermittent and occlusal pain in the left mandibular second molar.The patient had undergone filling restoration for caries before endodontic consultation.With the aid of cone beam computed tomography(CBCT),a large periapical radiolucency was observed,and curved root canals in a mandibular second molar were confirmed,depicting a severe and curved distolingual root.Nonsurgical treatments,including novel individualized preparation skills and techniques and the use of bioceramic materials as an apical barrier,were performed,and complete healing of the periapical lesion and a satisfactory effect were achieved.CONCLUSION A case of severely curved root canals in a mandibular second molar was successfully treated and are reported herein.The complex anatomy of the tooth and the postoperative effect were also evaluated via the three-dimensional reconstruction of CBCT images,which accurately identified the aberrant canal morphology.New devices and biomaterial applications combined with novel synthesis techniques can increase the success rate of intractable endodontic treatment.

Anatomic Variation in Palatal Root of Maxillary Second Molar: Endodontic Management

The aim of the present clinical case report is to describe the singular root canal anatomy and endodontic management of a maxillary second molar with two palatal roots and two separate canal orifices. A 60 years-old female Hispanic/Latino patient attended the Endodontic Department at University of Buenos Aires School of Dentistry with acute pain in her maxillary left second molar. Clinical radiographs examination revealed unusual root morphology. Cleaning and shaping were completed with 5.25% NaOCl irrigation, 15% EDTA solution and hand/rotary instruments. Filling was performed with gutta-percha points and resin-based sealer. After one year follow-up periapical radiographs and CBCT images showed healing in the area and patient was asymptomatic.

Incidence of C-shaped root canal systems in mandibular second molars in the native Chinese population by analysis of clinical methods

The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods.For the recognition of C-shaped root canal system,1 146 mandibular second molars were selected and examined.Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton's method.C-shaped canals were identified in 397(34.64%) mandibular second molars by radiography(type I,31.23%;type II,38.29%;type III,30.48%).Clinical examination showed that 449(39.18%) cases exhibited C-shaped canal systems(C1,22.94%;C2,48.11%;C3a,15.59%;C3b,13.36%).As for the result of the radiographic and clinical combined examination,C-shaped root canals were found in 473(41.27%) mandibular second molars(C1,21.78%;C2,45.67%;C3a,16.70%;C3b,15.86%).The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination(P,0.05).The study indicated a high incidence of C-shaped canal system in a Chinese population.The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.

Two Palatal Root Canals in a Maxillary Right Second Molar:One Case Report

牙根和根管的数目不是固定不变的,文献报道表明牙齿尤其是上颌磨牙根管存在着解剖变异。但是,上颌第二磨牙发生腭根双根管的可能性很低。在本文中,作者报道了一例右上颌第二磨牙腭根双根管的解剖变异。由于可能存在的上颌第二磨牙腭根管解剖变异,所以临床医生在牙髓病治疗过程中应注意术前对患牙进行影像学分析,术中可借助牙科手术显微镜等可视手段寻找可能存在的腭根解剖变异。

Maxillary Second Molar with Single Root and Single Canal—Case Report

The maxillary second molar contains three roots and three canals. Variations of the maxillary second molar are reported in numerous studies in vitro and in vivo. Dentists are required to have adequate knowledge related to root canal morphology and their possible variations. The aim of this study was to present a case report about a diagnosis and treatment in maxillary second molar with single root and single canal. It is concluded that the diagnosing of these unusual cases is of high importance for successful endodontic treatment of these teeth.

Three-dimensional computed topography analysis of a patient with an unusual anatomy of the maxillary second and third molars

We present a case of a patient with rare anatomy of a maxillary second molar with three mesiobuccal root canals and a maxillary third molar with four separate roots, identified using multi-slice computed topography (CT) and three-dimensional reconstruction techniques. The described case enriched/might enrich our knowledge about possible anatomical aberrations of maxillary molars. In addition, we demonstrate the role of multi-slice CT as an objective tool for confirmatory diagnosis and successful endodontic management.

[牙合]垫联合隐形矫治在第二磨牙锁[牙合]矫治中的应用

目的:比较[牙合]垫联合隐形矫治与单纯隐形矫治用于第二磨牙锁[牙合]矫治的效果。方法:选择第二磨牙中、重度锁[牙合]患者30例(女16例,男14例),均为双侧锁[牙合]。年龄16.5~28岁。5例接受单纯隐形矫治(对照组),25例首先戴用[牙合]垫加弹性牵引解除锁[牙合],再行隐形矫治(联合组)。比较两组的矫治效果。结果:联合组矫治进程顺利,平均用时18个月,其中应用[牙合]垫加弹性牵引解除锁结关系需1.5~3个月。而对照组患者均未能顺利完成矫治,在戴用约10副隐形矫治器后,仍易脱套,暂停隐形矫治,重启方案后,约10副隐形矫治器后解除锁[牙合],用时14~15个月,相对于联合组多花费约12个月。结论:对于中、重度第二磨牙锁[牙合],在隐形矫治前应用[牙合]垫加局部交互牵引可顺利完成治疗,减少治疗时间。

第二磨牙萌出障碍的检出率变化及病因调查

目的:调查近年相对于二十多年前第二磨牙萌出障碍的检出率变化,并分析病因。方法:以在作者所在医院就诊的患者病历资料为研究对象,并按照就诊年代分为二十年前组和近年组。比较两组第二磨牙萌出障碍的检出率,分析主要病因以及与错牙合畸形类型的关系。结果:近年组的检出率及患牙数明显高于二十年前组(P<0.01)。两组中,由萌出方向异常和或间隙不足而导致的患牙数明显高于其他原因导致的患牙数(P<0.05)。第二磨牙萌出障碍好发于下颌,与第三磨牙存在与否无明显关系。在第二磨牙萌出障碍的病例中,骨性Ⅰ类均角最多见,骨性Ⅱ类多于骨性Ⅲ类,高角多于低角。结论:近年第二磨牙萌出障碍的检出率与二十多年前相比明显增加,主要病因为第二磨牙的萌出方向异常和/或间隙不足。第二磨牙萌出障碍好发于骨性Ⅱ类和高角的患者。

下颌第二磨牙牙冠延长术后疗效观察及其风险因素分析

目的:观察下颌第二磨牙牙冠延长术后治疗效果,确定其风险因素;探讨风险因素个数对其疗效的影响。方法:纳入2019~2021年于天津市口腔医院接受牙冠延长术的下颌第二磨牙314颗。6周复查时,按照拟定标准将其分为效果良好组和效果欠佳组。筛选影响两组患牙疗效的风险因素,并分析其数量与治疗效果的相关性。结果:314颗患牙中,成功者占88.54%,失败者为11.46%。龈缘-断端距离(P<0.01)、术前断端-嵴顶距离(P=0.032)及牙根形态(P=0.006)是影响术后疗效的风险因素。随着风险因素数量的增加,手术失败率呈线性增长的趋势,风险因素达到3个时,失败风险明显增高(P<0.01)。两者之间呈正相关(P<0.01)。结论:龈缘-断端距离、术前断端-嵴顶距离及牙根形态是影响冠延长疗效的风险因素,其数量与手术失败率之间呈正相关,风险因素达到3个时,失败风险明显增高,需谨慎选择适应证。

下颌第二磨牙根管治疗失败病例(126例)原因分析

目的:分析126例患者下颌第二磨牙根管治疗失败的原因。方法:选取笔者医院2017年10月-2021年8月门诊接诊的下颌第二磨牙根管治疗失败的126例患者(共126颗患牙)为研究对象,回顾性分析患者的临床资料,总结下颌第二磨牙根管治疗失败的原因。结果:126颗患牙中,遗漏根管48颗,欠填26颗,根管超充21颗,根充不致密35颗,牙根纵裂2颗,冠部折裂9颗;冠渗漏15颗,根管内器械分离3颗,底穿2颗,髓腔入路欠佳13颗,根管内台阶、偏移、侧穿17颗。结论:下颌第二磨牙根管系统复杂,解剖位置操作不方便,造成治疗失败的原因较多,主要有解剖学因素和医源性因素,重在预防,对治疗失败患牙应综合考虑相关因素采取合理的治疗方案。

数字化椅旁制作髓腔固位冠修复根管治疗后第二磨牙的短期临床评价

目的评价应用数字化椅旁技术制作全瓷髓腔固位冠修复根管治疗后第二磨牙的临床效果,并与传统纤维桩核冠修复进行对比。方法选择89颗经完善根管治疗后的第二恒磨牙,随机分为两组,应用CEREC椅旁数字化技术制作全瓷修复体:实验组42例46颗,行髓腔固位冠修复(玻璃陶瓷材料);对照组43例43颗,行桩核冠修复(玻璃纤维桩+玻璃陶瓷全冠)。采用改良USPHS标准分别于修复完成后第3、6、12个月对两组修复体的完整性、固位、边缘密合性、邻接关系、牙龈情况、牙体完整性等指标进行临床修复效果评价,并由患者填写满意度调查问卷。结果符合本研究纳入标准的患者共92例,患牙96颗,其中7例7颗患牙失访,最终共纳入患者85例(年龄20~69岁),患牙89颗(上颌42颗、下颌47颗),其中实验组42例,患牙46颗;对照组43例,患牙43颗。根据改良USPHS标准对修复体进行临床修复效果评价,评价为A代表临床优秀水平。研究显示修复1年后髓腔固位冠优秀率为97.7%,桩核冠为92.6%,其中两组修复体的完整性、固位、边缘密合性、邻接关系以及牙体完整性在1年观察期内差异无统计学意义,在牙周健康状况方面差异有统计学意义。结论应用数字化椅旁技术制作全瓷髓腔固位冠修复根管治疗后第二磨牙的短期临床效果与桩核冠相近,可作为第二磨牙修复的一种理想选择。

儿童颈椎骨龄、牙龄与年龄相关性研究

目的:探讨儿童颈椎骨龄、下颌第二磨牙钙化程度与年龄之间的关系,为正畸临床诊断和制定治疗方案提供依据。方法:回顾性分析210例8~16岁儿童的临床资料,通过数码头颅侧位片及口腔曲面断层片对其颈椎骨龄及左下颌第二磨牙钙化程度进行测量,采用相关性分析颈椎骨龄、下颌第二磨牙钙化程度与年龄之间的关系。结果:颈椎骨龄与年龄呈中度正相关(r=0.665,P<0.05);CS3、CS4、CS5三个阶段男性和女性间年龄差异有统计学意义,实际年龄多为12、13、14岁;下颌第二磨牙钙化程度与年龄之间呈显著相关性(r=0.925,P<0.05),随着儿童年龄的增长,儿童牙齿的钙化逐渐增高。结论:长治地区儿童颈椎骨龄及下颌第二磨牙钙化程度与年龄有相关性,正畸治疗中采用颈椎骨龄评估儿童生长发育是可靠的。

不同牙弓形态和第二前磨牙缺失对上颌磨牙远移中支抗的影响

背景:无托槽隐形矫治中磨牙远移产生的反作用力会导致支抗牙移位,即支抗丢失。有关牙弓形态和第二前磨牙缺失对支抗的影响尚未见报道。目的:运用有限元分析法研究牙弓形态和第二前磨牙缺失对上颌磨牙远移支抗控制的影响。方法:选取1名成年男性锥形束CT数据,建立上颌骨-上牙列-牙周膜-矩形附件-隐形矫治器模型,双侧上颌第二磨牙设计0.25 mm的远移量,首先,根据第二前磨牙是否缺失分为双侧缺失组与双侧存在组;然后,根据牙弓形态再分为尖圆形、卵圆形、方圆形安氏Ⅱ^(1)和方圆形安氏Ⅱ^(2)牙弓组,共计8组模型。在Ansys软件中计算各组模型支抗牙的位移及牙周膜应力分布。结果与结论:①无托槽隐形矫治器远移上颌第二磨牙后,第一磨牙和前磨牙出现近中倾斜伴伸长,前牙唇倾伴压低;②双侧第二前磨牙缺失后,各组模型第一磨牙前移量明显上升,而第一前磨牙和前牙前移量均减少;方圆形安氏Ⅱ^(1)牙弓组的前牙唇倾量最少,尖圆形牙弓最多,卵圆形牙弓组与尖圆形牙弓组差异不明显,方圆形安氏Ⅱ^(2)牙弓组略高于方圆形安氏Ⅱ^(1)牙弓组;③各组支抗牙牙周膜应力均集中于牙颈部和根尖区,方圆形牙弓组的牙周膜应力水平最低,相较其他组,方圆形牙弓组前牙牙周膜唇侧颈部应力亦明显缓解;④结果提示,方圆形牙弓在前牙支抗控制以及牙周膜应力分布方面更有利,安氏Ⅱ^(2)牙弓病例设计前牙唇倾时若配合磨牙远移可增加唇倾效率,磨牙远移时若第二前磨牙缺失不利于缺牙区空间的打开。

Extraction Timing of Heavily Destructed Upper First Permanent Molars

The first permanent molar as the first permanent tooth in the mouth and with a general insufficient oral hygiene of the children, is commonly subject to significant compromise which may arise due to caries or endodontic complication, or from developmental anomalies such as hypoplasia. Compromised teeth with questionable prognosis may result in short- and long-term clinical dilemmas. The aim of this research is to highlight the factors that require careful consideration when a compromised UFPM is detected and the importance of timely UFPM extraction to ensure the mesial drift of the upper second permanent molar (USPM) to fulfill the space of the extracted UFPM without any orthodontic intervention. For this purpose 52 heavily destructed UFPMs were extracted at age of 10.5 years old, 44 (84.6%) USPMs erupted exactly distal to the second premolar while only 7 (13.4%) USPMs erupted 1 mm distal to the second premolar. Clinically it is recommended to extract the heavily destructed upper first molars at age of 10.5 years old to ensure the complete closure of the extraction space by the passive mesial drift of upper second permanent molar.

显微根尖手术联合活髓保存术治疗阻生牙所致的下颌第二磨牙牙根外吸收

目的对阻生牙所致的下颌第二磨牙牙根外吸收的病例,提出一种新的治疗方式以保存患牙及其活髓。方法对临床诊断为阻生牙所致牙根外吸收的下颌第二磨牙,联合口腔颌面外科与牙体牙髓病科,在阻生牙拔除即刻,对第二磨牙外吸收的牙根通过显微根尖手术于外吸收部位清创并切除根尖,通过活髓保存术于截根面以生物活性材料直接盖髓。结果患牙牙根外吸收停止,术后1年随访患牙无症状,牙冠完整,牙髓组织正常,影像学检查根尖周未见透射影,牙周膜间隙正常,骨硬板连续,牙槽骨重建,预后良好。结论在阻生牙拔除同期联合显微根尖手术及活髓保存术,可保存阻生牙所致牙根外吸收的下颌第二磨牙牙髓活力,有望成为该疾病的候选治疗方案之一。

方丝旋转法矫治下颌第二磨牙舌倾的临床病例研究

目的:介绍方丝旋转法在矫治下颌第二磨牙舌倾中的应用并探讨其矫治效果。方法:从安阳市第六人民医院正畸科选取21例下颌第二磨牙舌倾的患者,使用方丝旋转法进行矫治,并对治疗前后头颅侧位片和全景片进行测量和比较。结果:所有患者下颌第二磨牙舌倾均得到矫治,与对颌牙建立了良好的咬合关系。矫治后牙根无明显吸收。矫治后下颌平面角略有增大,差异有统计学意义(P<0.05)。结论:方丝旋转法是一种简单、有效的矫治下颌第二磨牙舌倾的方法。

计算机辅助设计及机械加工全瓷高嵌体修复上颌第二磨牙大面积缺损的临床价值

目的:探讨计算机辅助设计及机械加工(CAD/CAM)全瓷高嵌体修复上颌第二磨牙大面积缺损的临床价值。方法:选取2018年1月—2020年1月于南京市中医院口腔科接受根管治疗的上颌第二磨牙大面积缺损患者105例(110颗患牙)为研究对象,根据随机数字表法分为观察组与对照组,各55颗患牙。观察组采用CAD/CAM全瓷高嵌体修复,对照组采用氧化锆全瓷冠修复。比较两组患者修复体成功率及存活率、牙体预备与修复体咬合调整耗时。结果:24个月后,观察组与对照组修复体成功率分别为94.1%、92.0%,存活率分别为100.0%、94.0%,两组比较差异无统计学意义(P>0.05)。观察组牙体预备、修复体咬合调整的平均耗时均短于对照组,差异有统计学意义(P<0.001)。结论:CAD/CAM全瓷高嵌体修复上颌第二磨牙牙体大面积缺损的临床价值显著,具有较高的修复成功率及存活率,可缩短牙体预备及修复体调改过程中咬合调整时间。

浓缩生长因子纤维蛋白膜联合Bio-Oss骨粉修复拔牙术后牙槽骨缺损疗效分析

目的:探讨浓缩生长因子纤维蛋白膜联合Bio-Oss骨粉修复拔牙术后牙槽骨缺损的疗效。方法:选择2018年1月-2020年1月笔者医院收治的因拔除下颌阻生第三磨牙致第二磨牙远中骨缺损患者76例,予以随机数字表法分为对照组(Bio-Oss骨粉植入,38例)和观察组(CGF膜联合Bio-Oss骨粉植入,38例)。手术后3 d复诊观察患者术后疼痛、开口度情况,比较两组患者术后1周创面愈合情况以及术前、术后1个月和3个月牙槽骨密度、牙槽嵴高度及牙槽嵴宽度,记录术后不良反应。结果:对照组术后3 d VAS评分(3.35±0.47)分,观察组为(2.67±0.42)分,对照组开口度(2.75±0.46)cm,观察组(2.68±0.51)cm,两组比较差异均无统计学意义(P>0.05)。术后1周,观察组创面愈合情况好于对照组,差异有统计学意义(P<0.05);术后1个月、术后3个月,观察组牙槽骨密度、牙槽嵴高度、牙槽嵴宽度均高于对照组,差异有统计学意义(P<0.05)。对照组术后不良反应发生率23.68%,高于观察组的5.26%,差异有统计学意义(P<0.05)。结论:浓缩生长因子纤维蛋白膜联合Bio-Oss骨粉在第二磨牙远中骨缺损修复中发挥着重要作用,值得临床推广应用。