Endodontic Access Cavity Preparation Research Articles

Access cavity preparation training using haptic virtual reality and microcomputed tomography tooth models

To evaluate the effectiveness of haptic virtual reality (VR) simulator training using microcomputed tomography (micro-CT) tooth models on minimizing procedural errors in endodontic access preparation. Fourth year dental students underwent a pre-training assessment of access cavity preparation on an extracted maxillary molar tooth mounted on a phantom head. Students were then randomized to training on either the micro-CT tooth models with a haptic VR simulator (n = 16) or extracted teeth in a phantom head (n = 16) training environments for 3 days, after which the assessment was repeated. The main outcome measure was procedural errors assessed by an expert blinded to trainee and training status. The secondary outcome measures were tooth mass loss and task completion time. The Wilcoxon test was used to examine the differences between pre-training and post-training error scores, on the same group. The Mann-Whitney test was used to detect any differences between haptic VR training and phantom head training groups. The independent t-test was used to make a comparison on tooth mass removed and task completion time between the haptic VR training and phantom head training groups. Post-training performance had improved compared with pre-training performance in error scores in both groups (P < 0.05). However, error score reduction between the haptic VR simulator and the conventional training group was not significantly different (P > 0.05). The VR simulator group decreased significantly (P < 0.05) the amount of hard tissue volume lost on the post-training exercise. Task completion time was not significantly different (P > 0.05) in both groups. Training on the haptic VR simulator and conventional phantom head had equivalent effects on minimizing procedural errors in endodontic access cavity preparation.

Repair of Furcal Iatrogenic Perforation with Mineral Trioxide Aggregate: Two Years Follow-up of Two Cases

Furcal perforation is usually an undesired complication that can occur during preparation of endodontic access cavities or exploring canal orifice of multirooted teeth. Inadequacy of the repair materials has been a contributing factor to the poor outcome of repair procedures. On the basis of the recent physical and biologic property studies of the relatively new introduced mineral trioxide aggregate, this material may be suitable for closing the communication between the pulp chamber and the underlying periodontal tissues. There are few reports on repair of furcal perforation with MTA in molar teeth. The purpose of this case report was to describe the treatment of two furcal perforation using MTA in molar teeth. The perforations were cleaned with NaOCl and saline solution and sealed with MTA without internal matrix. Finally, the teeth were endodontically treated and coronally restored with composite resin and ceramic veneer crown and bridge. After 2 years, the absence of periradicular radiolucent lesions, pain, and swelling along with functional tooth stability indicated a successful outcome of sealing perforations in two cases.

A preliminary study on the technical feasibility and outcome of retrograde root canal treatment

To investigate the technical feasibility and outcome of retrograde root canal treatment. Endodontic access cavity preparation in abutment teeth may jeopardize the retention of the coronal restoration leading to prosthodontic failure. In such cases leaving the crown intact and performing retrograde root canal treatment might be an alternative approach. The potential to promote healing with retrograde endodontic treatment, and the technical feasibility to shape, clean and fill the canal was evaluated retrospectively. The study consisted of 21 incisors, canines and premolar teeth followed-up clinically and radiographically from 6 to 48 months. In 14 teeth the canals were completely negotiated. These cases were all judged as completely healed. In five cases no canal could be explored by files and a conventional ultrasonic root-end preparation and filling was performed. Two of these were classified as completely healed and three as 'uncertain'. In 2 two-rooted premolars a combination was performed with complete instrumentation of the buccal canal and the ultrasonic root-end preparation of the palatal root. One case was judged as a failure and the other was classified as completely healed. The results from this preliminary evaluation of retrograde root canal treatment are promising and merit a randomized clinical trial. Abutment teeth with vital pulps may develop pulp necrosis and apical periodontitis in 10% of cases. Endodontic access preparation through an artificial crown may weaken its retention and jeopardize the longevity of a bridgework. Retrograde root canal treatment is often feasible in maxillary teeth. Results from this preliminary study suggest that treatment outcome for retrograde and orthograde root canal treatment is similar.

A practical guide to endodontic access cavity preparation in molar teeth

The main objective of access cavity preparation is to identify the root canal entrances for subsequent preparation and obturation of the root canal system. Access cavity preparation can be one of the most challenging and frustrating aspects of endodontic treatment, but it is the key to successful treatment. Inadequate access cavity preparation may result in difficulty locating or negotiating the root canals. This may result in inadequate cleaning, shaping and filling of the root canal system. It may also contribute to instrument separation and aberrations of canal shape. These factors may ultimately lead to failure of treatment. Good access cavity design and preparation is therefore imperative for quality endodontic treatment, prevention of iatrogenic problems, and prevention of endodontic failure.

Dilaceration: Review of an Endodontic Challenge

Dilaceration is the result of a developmental anomaly in which there has been an abrupt change in the axial inclination between the crown and the root of a tooth, but the criteria in the literature for recognizing root dilaceration vary. Two possible causes of dilaceration are trauma and developmental disturbances, and it has also been proposed that it might be associated with some developmental syndromes. Dilaceration can be seen in both the permanent and deciduous dentitions, and it is more commonly found in posterior teeth and in the maxilla. Periapical radiographs are the most appropriate way to diagnose the presence of root dilacerations. Diagnosis, endodontic access cavity preparation, root canal preparation and filling, and other related treatments might be complicated by the presence of a dilaceration. A review of the literature and a discussion of the options for managing this condition are presented.

Perforation repair with mineral trioxide aggregate: a modified matrix concept

To present a modified matrix concept for repair of root perforations using mineral trioxide aggregate (MTA). Root perforations may occur during preparation of endodontic access cavities or during post-space preparation. The perforation creates the potential for an inflammatory reaction in the periodontal ligament. A concept for the repair of root perforations is presented using a matrix of resorbable collagen. This matrix reconstructs the outer shape of the root and facilitates the adaptation of MTA. The indications for the use of MTA are discussed. Two clinical cases of 5-year successful root perforation repair using the technique are presented. Long-term perforations with periodontal inflammation can be successfully treated with MTA. Matrices for MTA placement can be developed with commercially available collagen. Infection control within the root canal and at the perforation site is required for satisfactory perforation repair and healing.

The Benefit of the Operating Microscope for Access Cavity Preparation by Undergraduate Students

Although studies show the operating microscope (OM) provides benefits for endodontists, the benefit to undergraduates has not been evaluated as completely as for specialists. The purpose of this study was to determine whether using the OM would improve students' performance in endodontic access cavity preparation and canal identification. Thirty-six dental students prepared access cavities and located canals in extracted maxillary molars, before and after training, which varied according to group. The standard group received a lecture and practice in preparation of access cavities. The microscope group received identical instruction using the OM. The control group received lectures only. All groups received equal content and instruction time (2 hr 20 min). Faculty graded preparations according to a multidimensional 5-point rating scale. Using the OM, the microscope group improved significantly in access cavity preparation (p <0.05) and significantly outperformed both standard and control groups in accuracy of identifying canals (p <0.05).

The effect of the endodontic access cavity on the marginal leakage of crowns

The marginal integrity of the crown can be broken during endodontic access cavity preparation due to the vibration of burs. Therefore, the purpose of this study was to evaluate the effect of endodontic access cavity preparation on the marginal leakage of full veneer gold crowns. 24 intact molars were mounted in acrylic resin blocks and prepared for crowns by a restorative dentist and crowns were cast with gold alloy. 20 Crowns were cemented with glass ionomer cement and 2 crowns were not cemented for positive control. 200 thermo-cycles from 5 to 5 with a travel time of 20s were completed. Then samples were randomly divided into 2 experimental groups of 9 each. Endodontic access preparation and zinc-oxide eugenol temporary fillings were done in Group 1. Teeth in Group 2 were not treated. Samples were coated with 2 layers of nail varnish and were immersed in 1% methylene blue dye for 20 hrs. Endodontic access was prepared in 2 samples, which were coated with nail varnish on all surfaces for negative control. After washing in running water gold crowns were cut with a #330 bur. Four buccolingual sections, 2 mm apart, were cut from the central section of each tooth and were examined and scored under the microscope for dye leakage. Score 1: leakage to the cervical 1/3 of the axial wall, Score 2: leakage to the middle 1/3 of the axial wall, Score 3: leakage to the coronal 1/3 of the axial wall, Score 4: leakage to the occlusal surface. The median value for Group 1 is 4 and for Group 2 is 2. The result of this study showed that samples in Group 1 leaked more than those in Group 2. This finding was significant(P

The effect of endodontic access cavity preparation and subsequent restorative procedures on molar crown retention.

Preparation of an endodontic access cavity through a full crown may affect its retention. This study was undertaken to investigate the effects on molar crown retention of endodontic access cavities and their subsequent restoration. Thirty human molars were mounted in resin, crown preparations were cut and their surface areas were determined. Vented metal copings were cemented with zinc phosphate and the forces required to displace each coping were measured using a tensile-testing machine. The copings were recemented, access cavities were cut and their surface areas determined prior to the displacement forces being re-measured. The copings were recemented, assigned to two groups, and the access cavities were restored--Group 1 with amalgam; Group 2 with glass ionomer (GIC). Displacement forces were re-measured and the copings were recemented. The occlusal margins of the access cavities were bevelled and restored again prior to displacement forces being remeasured. Mean displacement forces were - Group 1: Original (kg force), 37.86 +/- 3.97; After access cavity, 29.28 +/- 3.22; Amalgam, 50.21 +/- 4.71; Amalgam + bevel, 46.45 +/- 6.21. Group 2: Original, 42.77 +/- 4.49; After access cavity, 39.25 +/- 5.91; GIC, 48.11 +/- 3.55; GIC + bevel, 39.63 +/- 5.31. Statistical analyses with paired t tests showed that retentive values with access cavities were significantly lower than with intact crowns. Amalgam or GIC restorations increased retention beyond original values, significantly with amalgam. Bevelled occlusal margins decreased retention of crowns with restored access cavities but this was not significantly different from the original values. A significant relationship existed between total surface areas of the crown preparations, areas of the occlusal tables, and retentive values for crowns without access cavities. The access cavity area, as a proportion of the total area of the preparation, was related to the decrease in retention.

The effect of endodontic access cavity preparation and subsequent restorative procedures on incisor crown retention

Endodontic treatment often will require access through existing crowns. This study was undertaken to determine whether endodontic access cavity preparation affected the retention of crowns in anterior teeth and then to determine whether this retention can be regained by amalgam or post-retained amalgam restorations. Twenty extracted human incisors were mounted in acrylic blocks and prepared for crowns. Metal copings were fabricated and cemented with zinc phosphate cement and the forces required to displace the copings after various procedures were measured with a tensile testing machine. Retention values for all stages were compared with the initial retentive value for each coping without an access cavity which was set at 100 per cent. Group one specimens had the following means: copings with access cavity, 85.64 +/- 28.65 per cent of the initial values; amalgam flush with lingual dentine, 95.81 +/- 36.2 per cent; amalgam flush with coping, 114.89 +/- 34.5 per cent. Group two means were: copings with access cavity, 89.95 +/- 21.42 per cent; posts and amalgam, 177.37 +/- 77.5 per cent. Statistical analysis with the two sample t test showed that retention with post-retained amalgam restorations showed significantly higher values when compared with access cavities without restorations (p < 0.05). Retention values for post-retained restorations were significantly different from those just using amalgam. This study demonstrated that endodontic access cavities reduced the retention of the crowns, and subsequent restoration with amalgam or a post can regain the retention.(ABSTRACT TRUNCATED AT 250 WORDS)

Student endodontic access cavity preparation: Performance versus perception

A voluntary critique of endodontic access preparations was offered to all graduating seniors upon completion of the terminal endodontic clinical post-test. The purpose of the critique session was to evaluate a student's self-assessment skills and to determine whether any benefits occur from the review. The students were not informed of this purpose. The students that participated scored higher on the state board examination than those that did not participate in the self-critique session.