Analisi alla Cone Beam Computed Tomography della simmetria anatomica in molari superiori ed inferiori

AimTo analyze the symmetry in root canal configurations in the maxillary and mandibular permanent molar teeth of a Caucasian population using Cone Beam Computed Tomography (CBCT).ResultsOf 45 patients who had both maxillary first molars, 32 (71.1%) had perfect symmetry in the root and canal morphology of homonym teeth on the opposite side. As regards the maxillary second molars, the symmetry was observed in 43 patients (79.6%) of 54. Of 34 patients who had both mandibular first molars, 24 (70.6%) showed a perfect symmetry in the root and canal morphology of homonym teeth on the opposite side. As regards the mandibular second molars, the symmetry was observed in 47 patients (81%) of 58.ConclusionsCBCT is an exciting and clinically useful tool in studying root canal morphology and so the symmetry between homonym teeth.     

Symmetry of Root and Root Canal Morphology of Maxillary and Mandibular Molars in a White Population: A Cone-beam Computed Tomography Study In Vivo

Introduction

The aim of the present study was to use cone-beam computed tomography (CBCT) to analyze root canal anatomy and symmetry of maxillary and mandibular first and second molar teeth of a white population.

Methods

A total of 201 patients who required CBCT examinations as part of their dental diagnosis and treatment were enrolled in the present study. Overall, 596 healthy, untreated, well-developed maxillary and mandibular molar teeth (161 maxillary first molars, 157 maxillary second molars, 117 mandibular first molars, and 161 mandibular second molars) were examined by CBCT to establish the symmetry in root and canal anatomy between right and left sides in the same patient by evaluating the number of roots and root canals and the root canal configuration.

Results

Three separate roots with 3 separate canals was the normal anatomy of maxillary first and second molars. Most mandibular first and second molars had 2 separate roots, and the majority had 3 canals. In the present study, first molars, both maxillary and mandibular, exhibited greater asymmetry than the second molars. Maxillary first molars were found to be symmetrical in 71.1% of patients, whereas maxillary second molars were symmetrical in 79.6%. The remaining 28.9% and 20.4% of patients, respectively, showed asymmetry. Around 30% of the mandibular first molars and 20% of the mandibular second molars showed asymmetry.

Conclusions

The results of the present study reported a percentage of symmetry that varied from 70%–81%. These variations in symmetry should be taken in high consideration when treating 2 opposite molars in the same patient, because their anatomy may be different in up to 30% of the cases.     

Root trunk dimensions of 5 different tooth types.

The primary purpose of this study was to document mean, standard deviation, and range of root trunk dimensions of multirooted tooth types. A total of 412 extracted teeth were examined and classified as: maxillary first molars, maxillary second molars, maxillary first premolars, mandibular first molars, and mandibular second molars. The distance from the cementoenamel junction (CEJ) to the root groove and from the CEJ to the root division was measured. Mean CEJ to root groove distances ranged from 1.35 to 1.65 mm for maxillary first molars, from 1.49 to 1.89 mm for maxillary second molars, from 1.71 to 1.73 mm for maxillary first premolars, from 1.16 to 1.22 mm for mandibular first molars, and from 1.53 to 1.76 mm for mandibular second molars.     

Root and canal morphology of the mesiobuccal and distal roots of permanent first molars in a Kuwait population--a clinical study

Aim To identify the number of roots and canal configurations in permanent first molars of the indigenous Kuwaiti sub‐population and compare them against a similar group of non‐Kuwaiti population in different age groups and gender, and to determine the frequency of a second canal in the mesiobuccal root of maxillary first molars and distal root of mandibular first molars that could be located and treated in routine practice without using magnification or special lighting conditions. Methodology A total of 220 permanent first molar teeth of patients scheduled for root canal treatment over a period of 1 year were included. Patients were identified and grouped according to their nationality as Kuwaiti and non‐Kuwaiti (which included Filipinos, Indonesian Indians, Srilankans, Egyptians, Saudi Arabians and Syrians). In both nationality groups, patients were successively distributed into four groups based on their age. The first age group included patients below 20 years, the second 21–30 years, the third 31–40 years and the fourth were over 40 years. The first three groups comprised of 15 male and 15 female patients whilst the fourth group had 10 patients of each gender. Teeth with open apices, resorptions and calcification were excluded from the study. The teeth included were both clinically and radiographically examined for number of roots, the canal configuration and the presence of the additional mesiobuccal and distal canals and recorded. The simplified classification of canal configurations proposed by Weine was utilized. Results The incidence of a second canal in the mesiobuccal (MB) root of maxillary first molars and the distal root of mandibular first molars was not influenced significantly by nationality and gender. All the 110 maxillary first molars treated had three roots; 58% of MB root had one canal and 42% had two canals. The majority of the mesial roots had Weine type II canal configuration when the second mesiobuccal canal was present. All distobuccal and palatal roots had a single or type I canal configuration. Of the 110 mandibular first molars that were treated, 96% had two roots and 4% had three roots. When present, the third root was located either buccal or lingual to the main distal root. Overall 51% of the single distal roots had one canal whilst 49% had two canals. The mesial root frequently had a Weine type II canal configuration as did the distal root when a second canal was present. Pearson’s correlation analysis of both molars revealed a significant (P < 0.05) negative correlation (r = ?0.274, r = ?0.144) between age and number of canals as well as the type of canal. Conclusions The incidence of a second canal in distal roots of permanent mandibular first molars was 49% in the Kuwaiti population and this was similar to other Asian ethnic populations. Adopting modified access and troughing procedures revealed a 42% frequency of MB2 canals in maxillary first molars. The incidence of a second canal in both mesiobuccal roots of maxillary molars and distal roots of mandibular molars decreased significantly with age; no differences were noticed amongst the nationalities and gender studied. The possibility of extra roots should be anticipated in mandibular molars.     

Root canal configurations of third molar teeth. A comparison with first and second molars in the Turkish population

The purpose of the current study was to determine the similarities of maxillary and mandibular third molars with the other molar teeth. A total of 2016 extracted maxillary and mandibular permanent teeth were evaluated. The teeth were divided into six groups. The teeth were stored in 5% nitric acid solution for 7 days, then placed in increasing concentrations of ethyl alcohol. The teeth were rendered transparent by immersion in xylene solution for 4 days until complete transparency was achieved. Three roots were present in 93.0% of the maxillary molars, and 91.3% of the second molars. Among the maxillary third molars, 35.5% were single-rooted and 24.9% of the mandibular third molars had single roots. Double roots were present in 69.2% of the mandibular third molars, and 5.4% had three roots. Four new root canal configurations were encountered in this study. The root canal configurations of the mandibular and maxillary teeth showed similarities with the results of other studies performed in different populations.     

不同方法研究第一、第二磨牙的根管解剖形态

目的研究第一、第二磨牙根管解剖特点,为提高根管治疗的效果提供解剖学根据。方法采用肉眼、放大镜、牙科显微镜和透明牙标本观察四种方法,研究第一、第二磨牙的根管解剖特点。结果①经χ2检验,肉眼与放大倍数下对上颌第一磨牙近中颊侧第二根管（MB2）的检出率在统计学上有显著性差异（P〈0.05）。②152颗离体牙中,上颌第一磨牙64.91%存在MB2,下颌第二磨牙21.21%为＂C＂形根管。70.83%～77.55%的根尖孔为侧向开口。结论熟知第一、第二磨牙根管解剖特点对根管治疗的临床操作有指导意义。     

偏移投照技术与显微治疗诊治遗漏根管的疗效分析

目的分析根管治疗术后偏移投照技术与显微根管治疗的应用对遗漏根管的发现与治疗的临床疗效。方法选择需行初次牙髓治疗的下颌前牙、下颌前磨牙、下颌第一、二磨牙及上颌第一、二磨牙共360颗(分别为49、68、62、50、85、46颗)。常规拍摄术前正位根尖片,并于根治后拍摄正位及20°～30°偏位根尖片,通过对比分析,对可疑遗漏根管的患牙,在显微镜下寻找及治疗遗漏根管。结果经显微治疗,360颗患牙中25颗(6.9%)确诊为遗漏根管,各牙位依次为3、5、5、4、6、2颗,其中23颗患牙发现并成功充填遗漏根管,2颗根管可找到但不完全通畅;正位发现8颗(2.2%),偏位发现23颗(6.4%),术后偏移投照发现率明显高于正位(P<0.05)。结论根治术后偏移投照技术与显微根管治疗对遗漏根管的发现与治疗有较大的帮助。     

Study of root canal accessibility in human primary molars

The aim of the present study was to provide a general scheme for pulpectomy of primary molars that may be useful for decision-making about negotiation of root canals and selection of appropriate instruments. A total of 160 vital primary molars in 85 patients (40 males, 45 females) aged 4-6 years were selected. After taking primary radiographs, local anesthesia was induced, and the teeth were isolated using a rubber dam. Canal accessibility index (CAI) and tooth accessibility index (TAI) were calculated according to initial file size. Mandibular first molars had either three canals (79.2%) or four canals (20.8%), and all second molars had four canals. Maxillary first molars had three canals and second molars had either three canals (70.9%) or four canals (29.1%). Lower accessibility of the mandibular first molar distobuccal root accounted for the lower accessibility of these teeth in comparison with mandibular second molars. While three-canal maxillary second molars were more accessible due to the lower accessibility of the distobuccal canal of the maxillary first molar, poor accessibility of the distal canal in four-canal second molars was responsible for the difficult accessibility of these teeth. In conclusion, it seems that the accessibility of a single canal in each tooth determines the difficulty of accessibility for any given tooth. Moreover, while primary second molars are more accessible than first molars, all of them are negotiable.     

A scanning electron microscopic investigation of accessory foramina in the furcation and pulp chamber floor of molar teeth

Observations of the pulp chamber floor and furcation surface of human maxillary and mandibular first and second molars were made with the scanning electron microscopic to determine the incidence, size, and location of patent accessory foramina. Accessory foramina on both the pulp chamber floor and the furcation surface were found in 36% of maxillary first molars, 12% of maxillary second molars, 32% of mandibular first molars, and 24% of mandibular second molars. Mandibular teeth had a higher incidence (56%) of foramina involving both the pulp chamber floor and furcation surface than did the maxillary teeth (48%).     

A survey of approximal root concavities in an ethnic Chinese population

Eight hundred and forty teeth were surveyed, 60 approximal surfaces for each tooth type being studied. Approximal root concavities were completely absent in maxillary central incisors, in contrast with mandibular central incisors of which 73% had concavities on mesial surfaces and 93% on distal surfaces. Similarly, a markedly higher prevalence was found for mandibular lateral incisors and canines. However, mandibular first and second molars had fewer approximal concavities than their maxillary counterparts. In maxillary teeth, concavities were more frequent on distal surfaces, while for mandibular teeth no definite pattern was seen. In both maxillary and mandibular teeth, approximal concavities often started in enamel, extending down to the root surface. There were differences in the approximal root topography of Chinese teeth in comparison with other populations.     

自体牙移植300例临床分析

目的: 评价自体牙移植的临床效果。方法: 选取近5年行传统自体牙移植治疗的患者300例,分别从性别、年龄、受牙区牙位、受牙患病或缺失情况、供牙牙位、手术类型、术中引导骨再生(GBR)、术后根管治疗（RCT）及随访情况等方面进行统计分析。结果: 共移植牙300颗,男120例,女180例;年龄17~62岁,平均（32±9.18）岁;上颌第一磨牙45例,上颌第二磨牙28例,下颌第一磨牙104例,下颌第二磨牙123例,下颌磨牙共占75.67%。残根74例,残冠116例,牙折35例,根尖周炎16例,牙根吸收19例,龋坏及底穿19例,长期缺失21例。供牙来自上颌第三磨牙142例,下颌第三磨牙158例。同期手术191例,二期手术109例。仅用高度浓缩生长因子血纤维蛋白（CGF）40例,用CGF复合骨充填材料64例,用正海生物膜复合骨充填材料2例,仅用骨充填材料5例。活髓未行根管治疗23例,术中逆向行根管治疗3例,术后行根管治疗274例。术后随访≥5年23例,4年10例,3年43例,2年111例,1年65例,6个月48例。总成功率为86.67%,存留率为96.67%,失败率为3.33%。结论: 自体牙移植术作为一种修复牙列缺损的理想方法,简单易行、快速有效,生物相容性最好,值得广泛推广。     

Occurrence of Vertical Root Fractures after Apical Surgery: A Retrospective Analysis

IntroductionVertical root fractures (VRFs) are among the most frequent causes of tooth loss, mainly of endodontically treated teeth. However, very few data is available about the occurrence of VRFs following apical surgery.MethodsPatient charts from 864 patients with 1058 teeth treated with apical surgery (September 1999 to December 2018) were retrospectively evaluated, if a VRF had occurred after surgery. The following, possibly influencing factors were analyzed: sex and age, type of treated tooth, primary versus resurgery, technique of root-end preparation, and timepoint of VRF diagnosis. Endpoints were either tooth extraction or the last follow-up.ResultsThe study cohort (55% women, 45% men) had a mean age of 52.00 ± 13.97 years (range 9–93 years). The overall rate of VRFs after apical surgery was 4% (42 of 1058 teeth). Among these 42 teeth, 33.3% were mandibular first molars and 26.2% were maxillary second premolars. The most frequently affected root was the mesial root of mandibular first molars (28.6%). With regard to the study parameters, significant differences of VRF rates were observed only for the type of tooth treated.ConclusionsA low VRF rate of 4% was observed in this study. VRFs commonly occurred in maxillary premolars and mandibular molars, with the mesial root of mandibular first molars affected most frequently. This is in line with previous reports about VRFs in endodontically treated teeth without additional apical surgery.     

Group distal movement of teeth using microscrew implant anchorage

The purpose of this study was to quantify the treatment effects of distalization of the maxillary and mandibular molars using microscrew implants. The success rate and clinical considerations in the use of the microscrew implants were also evaluated. Thirteen patients who had undergone distalization of the posterior teeth using forces applied against microscrew implants were selected. Among them, 11 patients had mandibular microscrew implants and four patients had maxillary implants, including two patients who had both maxillary and mandibular ones at the same time. The maxillary first premolar and first molars showed significant distal movement, with no significant distal movement of the anterior teeth. The mandibular first premolar and first and second molars showed significant distal movement, but no significant movement of the mandibular incisor was observed. The microscrew implant success rate was 90% over a mean application period of 12.3 +/- 5.7 months. The results might support the use of the microscrew implants as an anchorage for group distal movement of the teeth.     

Long-term effect of root proximity on periodontal health after orthodontic treatment

The present investigation was done to evaluate the incidence and distribution of root proximity after orthodontic treatment and to test the hypothesis that interproximal areas with thin interdental bone provide less resistance against marginal periodontal breakdown than areas with normal width of bone between the roots. Only adult patients were examined at least 16 years after active orthodontic treatment. The distance between the roots was measured directly on periapical radiographs. Gingival health, level of connective tissue attachment, and clinical scores for bone levels in sites with thin interdental bone and neighboring or contralateral sites with normal width of bone between the roots were compared. Among the 400 patients studied, 25 had unilateral or bilateral areas with root proximity. Root proximity was diagnosed between maxillary central and lateral incisors in 18 patients, between mandibular central and lateral incisors in two patients, and between maxillary lateral incisor and canine, maxillary first and second molars, mandibular canine and first premolar, mandibular first and second premolars, or mandibular first and second molars in only one patient. No statistically significant differences in inflammation, level of attachment, and bone level were observed between root proximity sites and control sites. The results indicate that anterior teeth are not predisposed to more rapid periodontal breakdown when roots are in close proximity. Too few molar sites were included to draw conclusions regarding such areas.     

Analisi della morfologia radicolare e canalare di molari superiori ed inferiori in una popolazione Caucasica: studio in vivo alla CBCT

AimTo investigate the root and canal morphology of maxillary and mandibular permanent molar teeth in a Caucasian population by using Cone Beam Computed Tomography (CBCT).MethodsA total of 596 permanent molars were included. The number of roots, the number of canals per root and the root canal configurations according to the method of Vertucci were recorded.ResultsAlmost all of maxillary first molars (95.7%) had three separate roots; however, 40.3% of mesiobuccal roots had two canals (MB2). Of 157 maxillary second molars, 88.5% had three roots. Among the mesiobuccal roots, 15.1% had two canals. The majority of mandibular molars (100% of first molars, 89.4% of second molars) had two separate roots. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal.ConclusionsCBCT is an efficient method of studying root canal systems.     

上颌第一、第二恒磨牙牙根和根管系统的锥形束CT研究

目的：运用锥形束CT（CBCT）观察中国人群双侧上颌第一、第二磨牙的牙根和根管系统的解剖形态,为临床根管治疗提供依据。方法：选择200名患者的双侧上颌第一、第二恒磨牙（上颌第一恒磨牙354颗、上颌第二恒磨牙360颗）的CBCT扫描数据,使用NNT软件分析上颌第一、第二恒磨牙的牙根数、根管数、根管分型以及双侧对称情况。结果：上颌第一、第二磨牙主要为三根（99.44%和84.44%）。上颌第二磨牙的单根和双根较多见（15.28%）,其根管系统形态复杂,在根尖区有融合趋势。上颌第一磨牙的根管系统主要为3根四根管（78.97%）。上颌第二磨牙的三根管和四根管发现率接近（分别为47.37%和51.64%）。上颌第一磨牙的近颊根管系统主要根管分型为：Ⅳ型（57.79%）、Ⅱ型（19.83%）和Ⅰ型（15.58%）。上颌第二磨牙的近颊根管系统主要根管分型为：Ⅰ型（48.14%）、Ⅳ型（30.43%）和Ⅱ型（17.39%）。上颌第一、第二磨牙的远颊根和腭根主要为单根单根管,存在少量和罕见的变异。上颌第一、第二磨牙近颊根的根管数目和根管分型左右对称。结论：上颌第一磨牙近颊根管系统变异普遍存在,MB2根管为其主要的变异形式。上颌第二磨牙牙根数目和根管形态变异类型多,单根牙和双根牙的根管走向复杂多变。CBCT可以为识别根管形态提供准确依据。     

A preliminary in vitro study of the incidence and position of the root canal isthmus in maxillary and mandibular first molars

AIM: To investigate in vitro the incidence and position of the root canal isthmus in extracted mesiobuccal roots of maxillary and mesial roots of mandibular first molars. METHODOLOGY: Fifty maxillary and 50 mandibular molars were included in the study. The mesiobuccal roots of maxillary molars and the mesial roots of mandibular molars were sectioned from their crowns in the furcation region and embedded in clear resin. Transverse serial 1-mm-thick sections from the apical 6 mm were prepared. The apical side of each section was stained with India ink and observed through a light microscope. The sample images were saved to disk using a digital camera and the root canals in terms of the number present and the incidence and classification of isthmuses. RESULTS: In the mesiobuccal root of the maxillary first molars, 70% had one canal, whereas 29.5% had two canals. In the mesial root of mandibular molars, 41% had one canal, whereas 59% had two canals. In some sections, more than two canals were found close to the apical foramen. The isthmus incidence was greatest 3-5 mm from the apex. In teeth having two canals, a complete or partial isthmus was frequently observed in the sections between 3 and 4 mm from the apex. Of the isthmuses present, 22% were complete and 37% partial in mandibular molars and 17.3% were complete and 11.7% partial in maxillary molars. CONCLUSIONS: The incidence of isthmus in the mesiobuccal root of the maxillary first molars and in the mesial root of the mandibular first molars was high, particularly in sections 3-5 mm from the apex. Cleaning the isthmus is a major challenge during root canal treatment.     

因重度牙周炎拔除的磨牙根分叉形态测量及根柱凹陷发生率的调查

目的 :了解因重度牙周炎拔除的磨牙根分叉形态及根柱凹陷的发生情况。方法 :对因重度牙周炎拔除的 3 0个上颌第一磨牙 ,15个上颌第二磨牙 ,3 0个下颌第一磨牙及 10个下颌第二磨牙进行测量 ,记录牙根长度(RL) ,根柱长度 (RTL) ,釉牙骨质界处的近远中径 (MDD)和颊舌径 (BLD) ,根柱凹陷的有无 ,釉牙骨质界到根柱凹陷的距离及根分叉开口下 2mm的宽度。结果 :①无论是上颌还是下颌磨牙 ,第一磨牙牙根长度及根柱长度均较第二磨牙短 ,而第一磨牙颊舌径、近远中径及根分叉开口下 2mm处宽度均较第二磨牙大 ,其中仅 4.71%的牙根分叉开口下 2mm处宽度小于 0 .75mm。②上颌磨牙根柱凹陷发生率高于下颌磨牙 ( p <0 .0 5 ) ,且 89.41%的牙至少在一个面上从根柱凹陷到釉牙骨质界的距离为零。结论 :根柱凹陷可能是造成根分叉病变的原因 ,并可能是导致牙周治疗效果欠佳的原因。     

Incidence of patent furcal accessory canals in permanent molars of a Turkish population

Aim To determine the incidence of patent furcal accessory canals in permanent molars of a Turkish population. Methodology Two‐hundred extracted teeth consisting of 50 maxillary first molars, 50 maxillary second molars, 50 mandibular first molars and 50 mandibular second molars from Turkish patients attending the Oral Surgery Department of the Faculty of Dentistry, ?stanbul University, ?stanbul, Turkey, were included in the study. After preparation of access cavities and removal of pulp tissue, the teeth were stored in 5.25% sodium hypochlorite for 1 h. Following double‐sealing of the access cavities, all tooth surfaces except the furcation regions were covered with nail varnish. The teeth were stored in 0.5% basic fuchsin for 1 week. The teeth were sectioned at the cemento‐enamel junction and the presence of patent furcal canals was established by examining the pulp chamber floor with a stereomicroscope (10×) to determine staining. Results Patent furcal accessory canals were detected in 24% of maxillary first molars, 16% of maxillary second molars, 24% of mandibular first molars, and 20% of mandibular second molars. No statistically significant differences were found between the tooth types. Conclusions In a Turkish population, the incidence of patent furcal accessory canals on the pulp chamber floor of maxillary and mandibular first and second molars ranged between 16 and 24%.     

Use of cone-beam computed tomography to evaluate root and canal morphology of mandibular first and second molars in Turkish individuals

Objective: The aim of this study was to investigate the root and canal morphology of mandibular first and second molars in a Turkish population by using cone beam computed tomography (CBCT). Study design: CBCT images of mandibular first (n = 823) and second molar (n = 925) teeth from 605 Turkish patients were analyzed. The root canal configurations were classified according to the method of Vertucci. Results: The majority of mandibular molars (95.8% of first molars, 85.4% of second molars) had two separate roots; however, three roots were identified in 2.06% of first molars and 3.45% of second molars. C-shaped canals occurred 0.85% of first molars and 4.1% of second molars. Three canals were found in 79.9% of first molars and 72.8% of second molars. Most distal roots had a simple type I configuration, whereas mesial roots had more complex canal systems, with more than one canal. The most common root morphology of first and second molars is the two rooted morphology with three canals. Both the mesial and distal roots showed wide variations in canal anatomy with type IV and type I canal configuration predominating in the mesial and distal roots, respectively. Conclusion: Vertucci type I and IV canal configurations were the most prevalent in the distal and mesial roots, respectively, of both the mandibular first and second permanent molar teeth. Key words:Cone-beam CT, Turkish, mandibular molars, root and canal morphology.