Vertical root fractures

In this study, I review, clinically and radiographically, 303 patients with 460 single or multirooted endodontically treated teeth. In all teeth, the therapy was performed by me with the use of final restoration of the crown with or without post and full cast crown coverage after treatment. The teeth were functioning for at least 3 years, without having received any other type of dental work since then. I evaluated the existence of vertical root fracture, the function of the teeth, the type of root canal therapy, the type and length of the post, and the type of retention of the post used in all 460 teeth. After statistical evaluation of the results, I found that 3.69% of the teeth had had vertical root fracture. Computer analysis, simple correlation hypothesis, and distribution method with 1 degree of freedom revealed significant correlation between vertical root fracture and the technique of instrumentation and obturation of the canal (p = 0.025), the length of the post (p = 0.05), and the existence of the post (p = 0.05). On the contrary, I found no correlation between root fracture and type of retention of the prefabricated post used with respect to the method of obturation.     

Vertical root fractures: clinical and radiographic diagnosis

BACKGROUND: Early detection and management of vertical root fractures, or VRFs, remain a vexing issue that has caused needless suffering for patients as well as for dentists. The authors present techniques to aid the dentist in recognizing VRFs. METHODS: During a five-year period, the authors examined 36 patients who had VRFs. Absent control subjects and a larger number of patients, the authors did not design this investigation for statistical analysis. They diagnosed VRFs through dental histories and clinical and radiographic examinations. RESULTS: The study revealed VRFs in 36 teeth, two of which were vital and 34 of which were nonvital (that is, endodontically treated). The 34 VRFs resulted from excessive operative procedures performed in the root canal after endodontic therapy. Thirty-one of these 34 VRFs were caused by poorly designed dowels (too long, too wide or both) or inappropriate selection of the tooth as a bridge abutment; two VRFs were caused by a restoration that exerted lateral pressure on the axial walls of the preparation; and one VRF was caused by overzealous endodontic forces. The VRFs in the two vital teeth were in men who had a history of bruxism or clenching. CONCLUSIONS AND CLINICAL IMPLICATIONS: VRFs can be detected early by listening to the patient's chief complaints, carefully examining periapical and bitewing radiographs and performing a thorough clinical examination.     

Vertical root fracture and dentin deformation in curved roots: the influence of spreader design

The effect of lateral condensation using different tapered spreaders was evaluated. Curved mesiobuccal roots of maxillary molars were step-back prepared. Strain gauges applied to the root surfaces measured dentin deformation (distortion) during controlled lateral condensation with either fine finger or D11 spreaders. After obturation, roots were cross sectioned and analyzed under the stereomicroscope to detect the presence and pattern of fractures. The results showed no statistical difference between spreader designs as to mean distortion and the incidence of fractures; however several specimens in the D11 group showed high root distortion measurements. When fractures occurred, there were no consistent patterns of fracture in either spreader group. In conclusion, although there were no significant differences in mean deformation or fracture incidence in curved roots between the spreaders, the roots showing high deformation readings in the D11 group may be more susceptible to future vertical root fractures.     

Vertical root fracture and dentin deformation in curved roots: the influence of spreader design

Abstract The effect of lateral condensation using different tapered spreaders was evaluated. Curved mesiobuccal roots of maxillary molars were step-back prepared. Strain gauges applied to the root surfaces measured dentin deformation (distortion) during controlled lateral condensation with either fine finger or D 11 spreaders. After obturation, roots were cross sectioned and analyzed under the stereomicroscope to detect the presence and pattern of fractures. The results showed no statistical difference between spreader designs as to mean distortion and the incidence of fractures; however several specimens in the D11 group showed high root distortion measurements. When fractures occurred, there were no consistent patterns of fracture in either spreader group. In conclusion, although there were no significant differences in mean deformation or fracture incidence in curved roots between the spreaders, the roots showing high deformation readings in the D11 group may be more susceptible to future vertical root fractures.     

Visual acuity of dentists under simulated clinical conditions

Objectives

This study examined the near visual acuity of dentists in relation to age and magnification under simulated clinical conditions.

Materials and methods

Miniaturized visual tests were performed in posterior teeth of a dental phantom head in a simulated clinical setting (dental chair, operating lamp, dental mirror). The visual acuity of 40 dentists was measured under the following conditions: (1) natural visual acuity, distance of 300 mm; (2) natural visual acuity, free choice of distance; (3) Galilean loupes, magnification of ×2.5; (4) Keplerian loupes, ×4.3; (5) operating microscope, ×4, integrated light; (6) operating microscope, ×6.4, integrated light.

Results

The visual acuity varied widely between individuals and was significantly lower in the group ≥40 years of age (p?<?0.001). Significant differences were found between all tested conditions (p?<?0.01). Furthermore, a correlation between visual acuity and age was found for all conditions. The performance with the microscope was better than with loupes even with comparable magnification factors. Some dentists had a better visual acuity without optical aids than others with Galilean loupes.

Conclusions

Near visual acuity under simulated clinical conditions varies widely between individuals and decreases throughout life. Visual deficiencies can be compensated for with optical aids.

Clinical relevance

Newly developed miniaturized vision tests have allowed, in a clinically relevant way, to evaluate the influence of magnification and age on the near visual acuity of dentists.     

根管治疗术后的牙根纵折

在根管治疗过程中,为了彻底清除根管内感染源和大锥度根管预备器械的使用,常使根管预备过度,导致根管壁变薄而使牙根易发生折裂。通常情况下,完全的牙根横折和斜折,通过常规的X线根尖片即可明确诊断,但当牙根纵折时,则由于其临床症状和X线根尖片表现多与根管治疗失败和某些类型的牙周病类似,而使诊断困难,常导致患牙或病变牙根的拔除。本文通过相关文献回顾,就根管治疗术后牙根纵折的发生率、病因、临床表现、诊断和治疗作一综述。     

Vertical root fractures in endodontically treated teeth: diagnostic signs and clinical management

A most frustrating complication to root canal therapy is vertical root fracture (VRF) in an endodontically treated tooth. Prognosis most often is hopeless and differential diagnosis from other pathoses may be difficult at times. Nevertheless, proper diagnosis is critical to distinguish a fracture complication from clinical manifestations of periodontal and endodontic diseases. This review emphasizes the importance of the correct diagnosis of VRF, describes the more typical clinical and radiographic features of this disorder, and summarizes its prevalence and multifactorial etiology.     

Vertical root fractures in endodontically treated teeth part I: clinical and radiographic diagnosis

A correct and quick diagnosis of endodontically treated vertically fractured teeth is important for two main reasons: (1) the differential diagnosis between the clinical and radiographic appearance of periodontal disease and endodontic failures, and (2) the delay in making the correct diagnosis will result in rapid loss of supporting bone, especially on the buccal side. Typical clinical signs in the maxillary and mandibular premolars and mesial root of the mandibular molars, which are the most susceptible roots and teeth, for fracture are a highly located sinus tract and a deep bony defect along the root facing the fracture line. In the maxillary and mandibular premolars and the mesial root of mandibular molars, typical bony radiolucencies are the halo, vertical and periodontal types. Radiolucency in the bifurcation was typical in vertical root fractures of mandibular molars.     

3种往复旋转单支镍钛器械预备模拟弯曲根管的效果比较

目的:评价3种往复旋转单支镍钛器械预备模拟弯曲根管的效果.方法:选择115个单弯树脂模拟根管,采用随机图表法分为Reciproc组(A组,28个)、One file组(B组,29个)、Wave One组(C组,29个)和对照组(D组,29个).按照说明书要求预备模拟根管,比较4组根管预备、树脂去除量、根管清理效果、中心...     

手用ProTaper对弯曲根管成形能力评价的研究

目的评价手用ProTaper对弯曲根管的成形能力。方法将16个弯曲人工根管随机分为2组,实验组(PT组)使用手用ProTaper按冠根向深入法预备根管,对照组(SS组)用不锈钢K锉按逐步后退法预备根管;根管预备过程中对人工根管进行数码照相,图像分析软件Image-ProPlus对根管的形态与位置变化进行测量、分析。结果PT组预备完毕时根管弯曲角度均值从预备前的36°减小到26°,弯曲半径均值未见增大,根管壁光滑、流畅,未见根管不良形态形成;SS组预备完毕根管弯曲角度均值减小到22°,弯曲半径均值从6mm增大至11mm,根管壁切削不均衡,出现了根管偏移、根尖孔拉开、根管台阶等不良形态。结论手用ProTaper对弯曲根管成形能力优于不锈钢K锉。     

Comparison of three instrumentation techniques in the preparation of simulated curved root canals

Forty-five acrylic blocks with simulated curved canals were divided into three groups of 15 blocks each. In group 1 the canals were instrumented with ultrasoni-cally energized K-files (UEF) using a piezoelectric ultrasonic device. In group 2 the canals were prepared with ProFile 0.04 Taper Series 29 Rotary Instruments (PRI) in conjunction with a low-speed high torque handpiece. In group 3 (control) the canals were hand instrumented (HI) with conventional K-type files using a standard push-pull circumferential technique. The efficiency of these techniques for preparing the simulated canals were compared by measuring the amount of transportation of the prepared canals at different levels from the working length using a double exposure photographic technique. A statistical analysis was used to indicate any significant difference among groups. The results showed that the use of PRI provided well-centred and more tapered preparations. Conversely, the use of UEF and HI resulted in frequent alteration of the original curvature, showing transportation at different levels from the working length.     

Vertical root fractures in adjacent maxillary premolars: an endodontic-prosthetic perplexity

Vertical root fractures in endodontically treated teeth occur frequently in teeth or roots in which their mesiodistal dimension is narrow, such as the maxillary upper premolars. Two cases of vertical root fractures in two adjacent maxillary reconstructed teeth are presented. As in many cases of vertical root fractures, the primary diagnosis was of endodontic treatment failure. The final diagnosis of the fractures was made either by the radiograph showing separation of root segments in one case, or by surgical exploration in the other. In both cases, tooth extraction was unavoidable.