dilaceration Flashcards
How do you define dilacerations and what is the prevalence of dilacerated roots in endodontics?
The term dilaceration, first used byTomes in 1848, refers to a sharp bend or curve in the root or crown of a formed tooth. It can also be defined as a deviation or bend in the linear relationship of a crown to its root. According to some authors (Hamasha, Al‐Khateeb & Darwazeh 2002), a tooth is considered to have a dilaceration toward the mesial or distal direction if there is a 90° angle or greater curve along the axis of the tooth or root. In contrast, others define dilaceration as a deviation from the normal axis of the tooth, 20° or more in the apical part of the root (Chohayeb 1983).
Dilaceration has been observed in both permanent and deciduous dentitions, but the inci- dence in the latter is very low (Bimstein 1978; Neville et al. 2002). Some researchers have reported that the prevalence is greater in posterior teeth and in the maxilla.There are fewer occurrences among anterior teeth and in the mandible. Furthermore, bilaterally occurring dilacerations might be seen in many patients (Ng et al. 2008), but bilateral dilacera- tion in both the maxilla and mandible of the same person is rarely found.There is no sex predilection for dilacerations of teeth.
What are the technical considerations for management of dilacerated root canals?
First, it is important to recognize the complexity of the case and to formulate a customized treatment plan for the management of curved canals. A step by step guide used to treat curved canals and reduce incidence of procedural errors is outlined below (Sakkir et al. 2014)
Access: In order to provide the most direct access to the apical foramen, enough tooth structure must be removed to allow the endodontic instruments to move freely within the coronal cavity. However, an important observation outlined by Luebke (Ingle
et al. 2002) states that an entire access cavity wall does not need to be extended in the event that instrument impingement occurs as a result of a dilacerated root. (Ingle et al. 2002) In extending only the portion of the wall needed to free the instrument, a cloverleaf appearance is created as the outline form. Luebke has termed this a “shamrock preparation.” (Ingle et al. 2002)This is a modified outline form to accommodate the instrument, unrestrained in severely curved canals.
Decreasing the restoring force caused by a straight file bending against the curved dentine surface can be done by the following:
1. Precurving the file: A precurved file traverses the
curve better than a straight file. Precurving is performed in two ways:
• Placing a gradual curve for the entire length of
the file
• Placing a sharp curve of nearly 45° near the
apical end of the instrument
2. Use of smaller number files: Smaller files have a
better ability to follow the canal curvature due to their flexibility. It is recommended that the smaller sized files negotiate the canal loosely prior to proceeding to the subsequent file size.
3. Use of intermediate file sizes:These files allow for an easier transition of instrument sizes resulting in smoother cutting in curved canals. Cutting 1 mm from the apex of a size #15 file converts it to a size #17 file as there is an increase of 0.02 mm of diameter per 1 mm of length.
4. Use of flexible files (nickel‐titanium files, Flex‐R® files):These files help in maintaining the shape of the curved canal and avoid procedural errors like ledging, elbowing, or zipping of the root canal.
Decreasing the length of actively cutting files is achieved by: Anti‐curvature filing or modifying the cutting edges of the instrument by dulling the flute on the outer surface of the apical third and inner portion of the middle third.This can be performed using a diamond file. Another way to accomplish this is by changing the canal preparation techniques, i.e., use of coronal pre‐flaring and crown‐down technique.
What are the current advancements in endodontic approaches to complex clinical cases?
According to Kishen et al. (2016), contemporary endodontics has seen unprecedented advancement in technology and materials, impacting all aspects of the specialty.
1. Endodontic imaging:The advent of cone beam computed tomography (CBCT) has resulted in widespread adoption of this technology for 3-D image capture and processing. CBCT greatly enhances diagnostic ability in circumstances when 2-D conventional radiographic interpreta- tion has limitations.
2. Root canal preparation: Engine‐driven instrumen- tation with nickel‐titanium (NiTi alloy) continues to be used more frequently by endodontists compared to hand instruments. Improved rotary instruments are constantly being introduced with the invention of more flexible alloys.This increased flexibility promises better canal nego- tiation and an extended fatigue life. Reciprocating motion techniques can reduce the number of instruments used per patient. In addition, the greatly improved NiTi files are designed to instrument a larger area of the canal wall and to decrease the need for coronal flaring.
3. Root canal disinfection: Current advances in endodontic disinfection are geared towards improving fluid dynamics during root canal irrigation.This is accomplished by improving bubble dynamics, activating intensified cavita- tional bubbles, and utilizing more effective antimicrobials. One example is developing irrigants that demonstrate improved antibiofilm effects over sodium hypochlorite.
4. Root canal filling: In recent years, new concepts have evolved that can improve and facilitate root‐ filling procedures. One example is to use a cal- cium silicate cement‐based sealer.These sealers are initially flowable and express bioactive proper- ties, i.e., they promote Ca/P precipitation in a wet environment. The interface that forms between the sealer and the root canal wall is calcium phos- phate and, thus, mimics nature. However, a core material, gutta-percha is still necessary.
These advances are aimed towards improving
contemporary Endodontics and enhancing state of the art treatment approaches needed to successfully complete complex cases.
What are the risks associated with managing a dilacerated root canal?
According to Hamasha et al. (2002), dilacerated canals can pose significant challenges to clinicians. Failures in treating dilacerated root canal cases result from an inability to maintain the natural anatomic root canal curvature.This may lead to the formation of ledges, apical transportation, zipping, perforation, or instrument breakage. In order to avoid these mishaps, the basic principles of endo- dontic therapy must be followed.These include good preoperative radiographs, straight‐line access to the apical foramen, precurving the endodontic hand instruments, recapitulation, copious irrigation, and the use of flexible NiTi instruments.
What are the factors that can affect the prognosis for this case?
Prognosis of this case as defined by the American Association of Endodontic Terminology would be categorized as favorable. However, prognosis depends on several factors including diagnosis. According to Sjogren et al. (1990), success rates are: vital teeth: 96% success rate – no microorganisms; PN (necrosis)–PL (lesion): 86%; PN–PL with overfill less than 2 mm: 76%; PN–PL with underfill more than 2 mm: 68%.
In a study by Ng et al. (2008), four conditions were found to significantly improve the outcome of primary root canal treatment.These conditions include the preoperative absence of a periapical radiolucency, a root filling with no voids present, the obturation extending within 2 mm of the radio- graphic apex, and a satisfactory coronal restoration. Consequently, the goals of successful root canal treatment are to maintain access to the apical anatomy during chemomechanical debridement, to obturate the canal with densely compacted material to the apical terminus without extrusion into the apical tissues, and to prevent reinfection with a good quality coronal restoration. In theToronto study (de Chevigny et al. 2008), the outcome of root canal treatment was assessed after 4–6 years. In teeth with radiolucencies, intra‐operative complica- tions (OR, 2.27; CI, 1.05–4.89; healed: absent, 84%; present, 69%) and root‐filling technique (OR, 1.89; CI, 1.01–3.53; healed: lateral, 77%; vertical, 87%) were additional outcome predictors. A better outcome was reported for teeth without radiolucencies, with single roots, and without mid‐treatment complications.
