Medico-legal aspects of vertical root fractures in root filled teeth.

AIM: To analyse the medico-legal aspects of vertical root fracture (VRF) following root canal treatment (RCT). METHODOLOGY: A comprehensive search in a professional liability insurance database was conducted to retrospectively identify cases of VRF following RCT. The complaints were categorized as either financial risk bearing or financial nonrisk bearing, and related demographic, prosthetic and endodontic variables were analysed. RESULTS: Seventy-seven legal cases of patients with VRFs following RCT were identified. Most of the cases were either in premolars or in mandibular molar teeth (P<0.05). Poor-quality root filling was associated with an extended delay of diagnosis (P<0.05). The presence of a post significantly increased the financial risk assessment (P<0.05). CONCLUSIONS: Poor quality root fillings complicate the diagnosis of VRF, which in turn extends the time for achieving an accurate diagnosis and increasing the medico-legal risk. Premolar and mandibular molar teeth were more prone to medico-legal claims related to VRF following RCT. Post should be placed only when essential for additional core support to avoid medico-legal risk.

The effect of maintaining apical patency on canal transportation.

AIM: To evaluate, ex vivo, the effect of maintaining apical patency on the original canal shape during preparation of curved roots by two different techniques. METHODOLOGY: Forty extracted human maxillary and mandibular molars were evaluated. Occlusal surfaces were ground and roots sectioned to the level of the cemento-enamel junction to allow only one root to remain for evaluation in each tooth. Specimens were divided into four experimental groups (10 canals each): Group 1--root canals prepared using the balanced force technique with stainless steel K-files, and patency established with size 10 K-files between each instrument; Group 2--same as Group 1 but without the use of a patency file; Group 3--canals instrumented with LightSpeed instruments and patency established with size 10 K-files between each instrument; and Group 4--same as Group 3 but without the use of a patency file. Specimens were mounted and a series of radiographs taken. Initial and post-preparation digital images were superimposed and the distance between two central axes at 1, 2 and 4 mm from the working length (WL) was measured to obtain an indication of the degree of apical transportation. Results were subjected to statistical analysis using two-way analysis of variance (ANOVA). RESULTS: No significant differences were found in degree of apical transportation at different levels of the root canal (P > 0.05) nor in loss of WL between groups (P > 0.05). CONCLUSION: In this laboratory study, maintaining apical patency did not influence canal transportation in the apical 4 mm.

Cracked and broken teeth--definitions, differential diagnosis and treatment.

Cracked and broken teeth present a diagnostic dilemma to the dentist and the sooner a correct diagnosis is made the greater are the chances to save the tooth. As the location, direction and size of the crack or fracture dictates the choice of treatment, it is important to first define the types of cracks and fractures in the coronal and radicular tooth structure. Cracks and fractures can be classified as follows: 1. craze lines 2. fractured cusps 3. cracked teeth 4. split teeth 5. vertical root fractures. The vertical root fracture has been described recently in two articles in this publication, and therefore will not be discussed here. Diagnosis of a cracked tooth is not always initially obvious. The patient's response to clinical testing is the primary diagnostic tool along with the dental history provided by the patient. Radiographs are secondary in making a diagnosis. Clinical aids for reproducing the patient's symptoms such as occlusal bite devices, observing occlusal wear facets and the application of cold water to one tooth at a time may isolate the offending tooth. In situations where an irreversible pulpitis is diagnosed, endodontic treatment is indicated. In the case of a questionable diagnosis, or one in which a potential reversible pulpitis is made, a provisional restoration can be placed for an unspecified time as a diagnostic aid. If endodontic therapy were indicated, consultation with the patient as to the compromised prognosis and the alternatives to endodontic treatment is essential.

[Root canal treatments in a patient with florid cemento-osseous dysplasia].

This article follows the comprehensive dental treatment of a patient who presented with multi periapical radiolucencies on a complete set of periapical radiographs. All the affected teeth were treated and root canal fillings were performed. None of the periapical radiolucencies showed any evidence of a healing process. On a later stage, the lesions have been diagnosed as florid cemento-osseous dysplasia. (In this article the correct diagnosis and treatment will be discussed).

[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.

[Vertical root fractures in endodontically treated teeth--Part II: Etiology and prevention].

The etiologic factors for vertical fractures in endodontically treated teeth are predisposing factors, such as loss of tooth material, anatomy of the susceptible teeth, moisture loss, previous dentinal cracks, and loss of bone support; and iatrogenic factors, such as excessive removal of radicular dentin as a result of endodontic and prosthetic procedures and improper selection of dowels. Identification of susceptible teeth and roots, proper selection and cementation of dowels, and avoidance of excessive force during condensation of gutta percha and in removal of tooth structure during endodontic and prosthetic procedures, are all measures that can be taken to prevent root fractures.

Statistical models for evaluating the penetrating ability of endodontic instruments.

An in vitro study was conducted to evaluate the penetrating ability of hand instruments (No. 10 K-file and "Pathfinder") and an automated device with a No. 08 (Canal Finder System) file in 270 extracted curved and narrow molar roots. The roots were randomly allocated to six groups, each one corresponding to a different permutation of the three instruments. The experiment was performed in three sequential stages, and Stages II and III were undertaken only in roots where no apical penetration was achieved in the previous stage(s). Statistical models were designed to fit the resulting clinical data. The No. 08 Canal Finder System and No. 10 K-file proved to be similar in their penetrating ability in Stage I (with estimated probabilities of 71.1% and 68.8%, respectively). The No. 08 Canal Finder was found to be the most efficient in Stage II and especially in Stage III, with a probability of penetration of 20.7%, compared with 9.8% for the "Pathfinder" and 7.4% for the No. 10 K-file.

A new muffle model system to study root canal morphology and instrumentation techniques.

A new muffle model system is presented using the principle of internal indexing. The system is composed of a metal stand, four pins, and a single Teflon mold that is used for the investment of all teeth. This system is very precise, reproducible, and versatile. The sectioned specimens can easily be stored assembled, as opposed to previous systems that rely on external indexing.

Furcation groove of buccal root of maxillary first premolars--a morphometric study.

Furcation grooves on the palatal aspect of the buccal roots of 35 maxillary first premolars, randomly selected, were assessed and found to exist in 97% of the sample. The buccal roots were sectioned into slices, 1 mm thick, and morphometric horizontal and vertical measurements were taken by a Toolmaker Microscope. The slice with the deepest invaginations served as the reference plane. The deepest invaginations were found to be at a mean distance of 1.18 mm from the bifurcation, with a mean depth of 0.4 mm. The canal had a kidney-shaped appearance in cross-section, and the mean distance from the invagination to the canal wall was 0.81 mm. It is thus hazardous to use rotary instruments for flaring these roots and any circular-shaped post space preparation at this level is contraindicated. The outcome of such procedures might be root thinning, perforation, or vertical root fracture, thus causing a poor prognosis.

Endodontic retreatment--case selection and technique. 3. Retreatment techniques.

The necessity to remove filling materials from the root canals is one of the major differences between primary endodontic therapy and retreatment. The obturating material has to be removed from the root canals before routine endodontic therapy can be performed. The removal of the material should not result in a change in the canal morphology, so that the objectives of endodontic therapy can be maintained. Numerous techniques may be used for removing filling materials and other obstructions from root canals. This article reviews the techniques that were suggested in the literature for this purpose and discusses their advantages and disadvantages.

Residual dentin thickness in mandibular premolars prepared with hand and rotatory instruments.

The residual dentin thickness in the coronal part of root canals of mandibular premolars after stepback preparation and flaring with Gates Glidden (GG) drills was assessed sequentially in a newly designed muffle device. Twelve extracted teeth were embedded in clear polyester resin, sectioned horizontally (1, 3, and 5 mm apically to the cementoenamel junction), and reassembled in the muffle device. The sequence of canal preparation was K-files to #40, then GG-2 and GG-4. After each procedure, the slices were separated and residual dentin thickness measured by a toolmaker microscope in four directions (buccal, lingual, distal, and mesial) and reassembled in the muffle device. Statistical analysis by three-way analysis of variance with repeated measures was undertaken. The difference in residual dentin thickness was highly significant with regard to instrument (control, K-40, GG-2, GG-4; p < 0.0001), slice (upper, middle, and lower; p < 0.0003), and direction (B, L, M, and D; p < 0.001). In each slice, the width of the mesial side was similar to the distal side, as was the buccal to the lingual sides. Reduction of residual dentin thickness in the mesiodistal direction, from the unprepared upper slice to the GG-4 prepared lower slice, was appreciably greater (35%) than in the buccolingual direction (5%).

Gutta-percha softening: "Hemo-De" as a xylene substitute.

The putative hazardous nature of chloroform and xylene implies that safer substitutes should be considered. Standard cylindrical gutta-percha samples were immersed in Hemo-De, a xylene substitute, for 60 s at 37 degrees C. Weight loss of a sample, after drying, was used as a measure of its solubility. Master and accessory cone gutta-percha of three brands were compared. The highest solubility of all kinds of gutta-percha was in chloroform, which served as a positive control. The average solubility of all samples in xylene and Hemo-De was 61% and 52% of that in chloroform, respectively. DMS gutta-percha was more soluble than of Hygienic and DeTrey. Master cone gutta-percha of all brands was more soluble than that of their accessory cones. These results indicate that (a) large differences exist in the solubility of gutta-percha and (b) Hemo-De dissolved gutta-percha in a range similar to that of xylene and may be considered as a potential substitute for this organic solvent.

The effect of immediate vs. delayed post space preparation on the apical seal of a root canal filling: a study in an increased-sensitivity pressure-driven system.

A 5 mm remaining length of root canal filling, after post space preparation, is commonly assumed to maintain sealing ability similar to that of the intact filling. Post spaces were prepared either immediately using hot pluggers, or later, using drills. The sealing ability of the fillings, 5 mm remaining length, were compared with each other and with an intact root canal filling control, using radioactive tracer in a pressure-driven system. When no pressure was applied, no differences could be detected between either of the groups and the control. When a pressure of 120 mm Hg was applied to the same teeth, the control group clearly maintained a better seal than each of the experimental groups, which did not significantly differ from each other. These results suggest that (a) the pressure-driven system was more sensitive than the passive leakage assay that failed to detect differences even at 14 days; (b) a remaining root canal filling of 5 mm was inferior to the intact root canal filling; and (c) the immediate post space preparation with hot pluggers did not differ from a delayed preparation with drills.

An evaluation of endodontically treated vertical root fractured teeth: impact of operative procedures.

Vertical root fractures of endodontically treated teeth are a frustrating complication that leads to extraction. The aim of the current survey was to evaluate the role of operative procedures in the etiology of this complication. A total of 154 endodontically treated vertical root fractured teeth were cleaned and washed after extraction and maintained in individual vials. Periapical radiographs before extraction, clinical findings and previous operative procedures were recorded. A post was observed in 95 teeth (61.7%), with 66 of these ending at the coronal third of the root. Most were screw posts of the Dentatus type (n = 64) and tapered cast posts (n = 14). A full crown was observed in 118 teeth, and 65 of these (55%) were extracted between 1 to 5 yr after final restoration. In 24 crowned teeth extraction was conducted within 1 yr after restoration and in 28 teeth after >5 years. It was concluded that post placement and root canal treatment are the major etiological factors for root fractures. Because signs and symptoms can appear years after the operative procedures in the root have been completed, coronal restorations would not interfere with the correct clinical diagnosis of vertical root fractures. Frequent recalls are recommended to diagnose vertical root fractures early, especially in susceptible teeth, such as premolars and mesial roots of mandibular molars.

An evaluation of endodontically treated vertically fractured teeth.

For this survey, 92 vertically fractured endodontically treated teeth were evaluated clinically and radiographically before and after extraction. The maxillary second premolars (27.2%) and mesial roots of the mandibular molars (24%) were the most fractured teeth. In 67.4% of the teeth, a solitary buccal pocket was present; in 34.8%, a fistula frequently appeared closer to the gingival margin than to the apical area. A lateral radiolucency or a combination of lateral and periapical radiolucency was found in more than half of the cases. The general practitioners correctly diagnosed vertical root fracture in only one-third of the 92 fractured teeth in this survey.

Densitometric measurement of radiopacity of Gutta-percha cones and root dentin.

National and international standards require that gutta-percha cones be sufficiently radiopaque to be distinguished from natural structures such as dentin and to permit evaluation of the density of the root canal filling. Discs, 1-mm thick, made from 15 commercial and experimental brands of gutta-percha cones, were tested for their compliance with the requirements. The radiopacity of 1-mm thick root dentin slabs was similarly measured with a photo-densitometer. All radiographs were made on D-speed occlusal film and replicated on E-speed film. The mean radiopacity of the gutta-percha discs on D-speed film was 7.26 mm of aluminum equivalent and 7.53 mm on E-speed film, greatly exceeding the minimal requirement of 3 mm. The difference in the values obtained with the two film types was not significant, suggesting that E-speed films may be used for the test. Dentin slabs were uniform in their radiopacity, equivalent to 1 mm of aluminum, confirming previous findings. In view of complaints of insufficient clinical performance, the present minimal requirement for radiopacity of gutta-percha cones seems too low.

Pattern of bone resorption in vertically fractured, endodontically treated teeth.

PURPOSE: To evaluate the clinical pattern of alveolar bone resorption associated with vertically fractured, endodontically treated teeth in correlation to clinical symptoms. MATERIAL AND METHODS: The pattern of bone resorption was evaluated in 66 maxillary premolars, 13 mandibular premolars, and 31 mesial roots of mandibular molars extracted during an 18-month period because of vertical root fractures. Type and duration of symptoms were recorded and correlated to the pattern of bone resorption. RESULTS: A V-shaped pattern osseous defect (dehiscence) was typical (91%) to the buccal plate rather than a U-shaped shallow, rounded, slow grade resorption in the palatal or lingual plate. Fenestration of the buccal plate was observed in 10 patients (9%). A positive correlation between type of symptoms and amount of buccal bone resorption was found (P <.0001). The resorptive defect was always facing the fracture line. CONCLUSIONS: A typical pattern of bone resorption in vertical root fracture cases as shown in this study can be helpful to the clinician in diagnosing vertical root fracture when an exploratory full flap surgical procedure is performed.

Radiographic features of vertically fractured, endodontically treated maxillary premolars.

OBJECTIVE: The purpose of this study was to evaluate the most frequent radiographic appearance of bony lesions associated with vertically fractured roots of endodontically treated maxillary premolars. STUDY DESIGN: The radiographic features of 102 endodontically treated teeth and their periradicular areas (51 with and 51 without vertically fractured roots) were evaluated and compared. RESULTS: The predominant appearance of the periradicular area in the teeth with vertically fractured roots was the "halo" lesion (57%); by contrast, in the non-vertically fractured roots group, a "periapical" radiolucent lesion was most frequently found (55%). Angular bone loss (14%) and periodontal radiolucency (14%) were also typical radiolucent lesions in the vertically fractured teeth. CONCLUSIONS: "Halo" lesion, perilateral radiolucency, and angular resorption of the crestal bone, combined with diffuse or defined but not corticated borders, indicated a high probability of vertical root fracture in maxillary premolars.