A 5-year Follow-up of Projector System-Based Endodontic Treatment: Case Series.

Endodontic rehabilitation of grossly mutilated teeth is challenging. It requires reconstruction of the tooth under proper isolation before the commencement of the endodontic procedure. The study was designed to assess the 5-year performance of projector system-based endodontic restoration. Two patients diagnosed with pulpal necrosis and chronic periradicular periodontitis were provided with "Projector Endodontic Instrument Guidance System-" (PEIGS) based endodontic treatment. After access cavity preparation, the canals were cleaned, shaped, and further enlarged to receive the projectors with a snug fit after effective etching. The incremental composite buildup was performed in a standardized manner. On successful curing, the files and the projectors were retracted sequentially. This was followed by a conventional root canal therapy. A 5-year follow-up showed an intact tooth structure and patient compliance in both cases. Although a technique sensitive procedure, the PEIGS provides promising results. Copyright:

Introduction

A grossly destructed or decayed teeth which require an endodontic treatment generally present with a minimum crown structure. Comprehensive rehabilitation of a grossly destructed tooth is challenging, especially during isolation. Therefore, the restoration of such a tooth before the commencement of endodontic treatment is crucial. Dental practitioners have been using hypodermic needles,[12] greater taper gutta-percha cones,[34] plastic delivery needles of metapex,[5] for restoration in such clinical situations. Meanwhile, Gerald N. Glickmann and Roberta Pileggi have developed a novel system called “Projector Endodontic Instrument Guidance System” (PEIGS).[6] The system consists of hollow plastic sleeves, which preserve the patency of the root canal and builds them up to the cavosurface margin. In the current study, the authors used a regular variety specially formulated nonadherent, linear low-density polyethylene PEIGS (CJM Engineering, Santa Barbara, CA, USA). It has a central lumen and an apical bevel bearing overall length: 10 mm, diameter 1 mm from the apical end: 1.2 mm, large diameter: 2 mm, with tapered lumen full length. The current case series describes the management of two clinical cases: (a) upper maxillary molar and (b) upper canine restored using PEIGS before the commencement of an endodontic rehabilitation.

Case Report

Case report 1

Patient presentation

A 32-year-old male patient reported to the institutional clinical setup with an oral history of mild, dull, and intermittent pain on the maxillary left posterior tooth region from 4 months. On intraoral examination, a grossly decayed tooth, tooth number 26 (based on a Fédération Dentaire Internationale [FDI] tooth numbering system), was identified. The tooth had two missing walls, and a subgingivally placed palatal wall [Figure 1a]. The tooth did not respond to a pulp sensitivity test. The preoperative intraoral periapical radiograph showed a deep occlusal caries involving the pulp [Figure 1b]. A widened periodontal space was observed on the palatal and distobuccal root surfaces. The case was diagnosed as a pulpal necrosis with chronic periradicular periodontitis.

Figure 1

(a) Preoperative image, (b) Corresponding IOPAR

Preplacement procedure

The placement of a rubber dam for isolation in this scenario proved complicated. Hence, the authors decided to employ PEIGS as the mode of isolation. After locally anesthetizing the patient, the clinician excavated caries, prepared the access cavity, and located three canals. The clinician performed a standardized cleaning and shaping of the canals and enlarged them to a file size of 20. The clinician used Gates-Glidden drills to further enlarge the canal orifices for the efficient positioning of the projectors. The authors used 37% phosphoric acid (Scotchbond etchant gel, 3M ESPE, St. Paul, MN, USA) to etch entire caries excavated enamel for 30 s total and dentin for 15 s. The procedure was followed by a water rinse and air drying, which revealed a white frosted appearance.

Projector placement and retrieval

The clinician placed the projectors on three endodontic files and slid them up to the filehandle. The placement ensured that 3–5 mm of each file tip projected past the end of the projector. Size 15 K-file was used for mesiobuccal and distobuccal canals and size 20 K-file for the palatal canal. The file with their individual projectors in place was introduced into its corresponding orifice [Figure 2a]. The clinician used cotton pliers to achieve a snug and an accurate fit of the projectors around the canal orifices. An application of a dentine bonding agent (Adper Single Bond, 3M ESPE, St. Paul, MN, USA) was performed in a conventional manner. The authors used a hybrid composite (Filtek Z100, 3M ESPE, St. Paul, MN, USA) for an incremental crown build-up followed by light curing. The author retracted the files through counter-rotation, without withdrawing the projectors. Later, the projectors were engaged by the flutes on their lumen by a size 50 H-File and rotated clockwise to disengage [Figure 2b]. The occlusal surface of the restoration was then leveled so as to provide a stable and ideal endodontic reference point.

Figure 2

(a) Projectors placement, (b) Coronal build-up with composite, (c) Rubber dam placement and canals enlarged, (d) Final postoperative IOPAR, (e) 5 years' follow-up of intact crown

Endodontic procedure

The working length was then established with an Electronic Apex Locator (Propex Pixi™, Dentsply-Sirona and Maillefer, Maillefer Instruments Holding Sàrl, Ballaigues, Switzerland) and standard instrumentation was performed to clean and shape the canals. The final cleaning and shaping were performed using Rotary File System (ProTaper®, Dentsply-Sirona and Maillefer, Maillefer Instruments Holding Sàrl, Ballaigues, Switzerland). The mesiobuccal and distobuccal canals were enlarged till F1 and the palatal canal till F2 [Figure 2c]. Thorough irrigation was done during the entire procedure using the EndoActivator system (EndoActivator®, Dentsply-Sirona and Maillefer, Maillefer Instruments Holding Sàrl, Ballaigues, Switzerland) with the final irrigation of saline. A self-cured sealing material (Cavit, 3M ESPE, St. Paul, MN, USA) was finally placed as an interim restorative material over a layer of cotton.

In the successive appointment, the interim restorative material was removed, and the canals were obturated. Composite resin was directly bonded over the obturated gutta-percha coronally to the height of the cavosurface margin [Figure 2d]. A full crown preparation was done on the preendodontic core buildup. On the succeeding visit, a crown was seated effectively. A 5-year follow-up showed an intact tooth structure and good patient compliance. An examination of the metal crown was performed using an articulating paper to identify the presence of any occlusal interference [Figure 2e].

Case 2

A 25-year-old female reported to the institutional clinic with mild pain with respect to the maxillary upper front tooth region from 2 months. On intraoral examination, deep proximal caries extending subgingivally with tooth number 23 (FDI tooth numbering system) was observed. No response was obtained to a pulp sensitivity test. A diagnosis was made as pulp necrosis with chronic periradicular periodontitis. A root canal treatment was performed using a PEIGS on one located canal using a single projector [Figure 3a and b]. The subsequent procedure for the management of the grossly destructed tooth was comparable to case 1.

Figure 3

(a) Projectors placed with canine, (b) Postoperative IOPAR

Discussion

Frequently endodontists encounter severely compromised teeth that require a preendodontic buildup of lost coronal structures to ensure a strong core, good coronal seal, placement of rubber dam, and to act as a reservoir for irrigation solutions.[7] Coronal leakage is one of the major contributors to endodontic failure. The reinforcement of the coronal tooth structure before endodontic treatment is essential in the overall outcome of the treatment.[2] A preformed copper band, an orthodontic band, or a temporary crown could be cemented over the remaining tooth structure. Nevertheless, it might compromise the sealing ability, and the cement might block the canal system while access opening or instrumentation and may lead to inflamed periodontal tissues due to improper placement/contour.[8] Isolation of grossly mutilated teeth can be effectively managed by applying a rubber dam with the help of gingivally approaching clamps, tiger clamps, and special clamps such as Silker-Glickman clamps.[9] Maintaining root canal patency during isolation of grossly destructed tooth is a great challenge, without blocking the root canals with the restorative material unintentionally.[3] The Canal projection system minimizes obstructions to a greater extent by closing the canal orifices, thereby preventing any displacement of restorative material into the canals during the preendodontic buildup. The PEIGS canals projectors are not technique sensitive, can be reused, but are not easily available. Although the hypodermic needles are easily available and are cheaper, the parallel outline of the needles makes it difficult to adapt to the conical root structure. Such a condition will require the fabrication of customized needles to attain a perfect fit. The greater taper gutta-percha is economical and easily accessible, but they are difficult to retrieve once mechanically engaged within therein.[10] The projector is a small, black, and cone-shaped plastic device, which slides onto an endodontic file. The projectors are nonadherent to the tooth and dental restorative materials, having a central lumen and an apical bevel. The PEIGS, in our case, helped to restore the coronal tooth structure using bonded composite restoration, thereby providing better sealing of the chamber floor, straight-line access during instrumentation, and reservoir for irrigants during instrumentation within the canals and prevented hazards resulting from inadvertent leakage of irrigants. This increases the success of the endodontic outcome, which in turn increases the longevity of the tooth to its full function within the oral cavity. A 5-year follow-up revealed an intact crown which could be due to a well-bonded composite restoration and minimal tooth preparation for a full-metal crown which was performed to reinforce the missing coronal tooth structure.

Conclusion

The PEIGS, though introduced years ago, has not been effectively used, either due to its unavailability or a lack of its knowledge among the general practitioners. The purpose is to rejuvenate the system rather than extracting a badly mutilated tooth. The PEIGS provides a preendodontic reconstruction of debilitated coronal and radicular tooth structure while preserving individualized access to each canal.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.