Reendodontic treatment

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possibilities apexlocators in endodontic therapy)

Retreatment in endodontics

21ST-CENTURY ENDODONTICS

Endodontics as a discipline has offered patients the opportunity to maintain their natural teeth. As the population expands and ages, the demand for endodontic therapy can be expected to increase as patients seek dental options to keep their teeth for a lifetime.

Retreatment in endodontics

 Over the past instrumentation, decade, microscopic nickel titanium endodontics, rotary digital radiography, a plethora of obturation systems, and biocompatible sealing materials have helped practitioners perform endodontic procedures effectively and efficiently than ever before.

more  Diagnosis, in fact, has become more challenging.

Overall, case management is more complex as geriatric patients and those who are medically compromised are more inclined to seek treatment to save their teeth.

Retreatment in endodontics

 Endodontics has gone through many changes in the past several years. Bacterial culturing of canals, the use of silver points, multiple endodontic visits, radiographic “guessing” of working lengths, and dependence on canal medicaments are fading concepts in endodontic treatment.

 Thanks to modern techniques used in endodontics, most of the teeth, which in the past would be removed currently can be saved. Many patients have had bad experiences associated with the "root canal therapy" and in this context often face a dilemma: whether to remove or cure? The latter approach is irreversible and should be treated as a last resort. We tried to make the treatment as light as possible, short and comfortable.

Retreatment in endodontics

 A variety of advancements in technology,materials, equipment, and even philosophy have changed how endodontic cases are managed.

 Electronic apex locators and other dentists.

and surgical microscopes have heightened precision and eliminated much of the uncertainty associated with endodontic procedures.

Digital radiography has expanded diagnostic abilities and increased the ability to communicate with patients

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Endodontic treatment consists of

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removing the contents of the chamber and canal system-the pulp (a network of blood vessels and nerves)

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the elimination of bacteria

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filling tightly root canals

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For that we use :

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modern tools to process canals

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systems for their filling

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apex locator to measure the length of the root

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dental RTG

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endodontics microscope

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Endodontic Services

Root Canal Therapy   With Rotary System With Apex Finder Re-Endodontic Treatment Apicectomy Hemisection Re-Implant Endodontic

Electronic apex locators

•Prior to root canal treatment at least one undistorted radiograph is required to assess canal morphology.

The apical extent of instrumentation and the final root filling have a role in treatment success, and are primarily determined radiographically.

•Electronic apex locators reduce the number of radiographs required and assist where radiographic methods create difficulty.

They may also indicate cases where the apical foramen is some distance from the radiographic apex.

 The removal of all pulp tissue, necrotic material and microorganisms from the root canal is essential for endodontic success. This can only be achieved if the length of the tooth and the root canal is determined with accuracy. The outcome of treatment of roots with necrotic pulps and periapical lesions is influenced significantly by the apical level of the root filling  Traditionally, the point of termination for endodontic instrumentation and obturation has been determined by taking radiographs. The development of the electronic apex locator has helped make the assessment of working length more accurate and predictable .

The importance of working length

 Grove (1930) stated that ‘the proper point to which root canals should be filled is the junction of the dentin and the cementum and that the pulp should be severed at the point of its union with the periodontal membrane ’.

The cementodentinal junction (CDJ) is the anatomical and histological landmark where the periodontal ligament begins and the pulp ends. Root canal preparation techniques aim to make use of this potential natural barrier between the contents of the canal and the apical tissues.

The importance of working length

 It is generally accepted that the preparation and obturation of the root canal should be at or short of the apical constriction. An in vivo histological study found that the most favourable histological conditions were when the instrumentation and obturation remained short of the apical constriction and that extruded gutta-percha and sealer always caused a severe inflammatory reaction despite the absence of pain .

 The problem clinicians face is how to accurately identify and prepare to this landmark filling lies within 2 mm of the challenging.

– the ‘working length ’ – and achieve maximum success. Epidemiological studies have reported that the best prognosis is when the root

radiographic apex

(Sjo ¨gren et al. 1990). The variations in anatomy of tooth apices both by age and tooth type make this task all the more

Anatomy of the apical foramen

  To appreciate fully the concept of working length, an understanding of apical anatomy is required. The anatomy of the apical foramen changes with age.

Figure 1a shows a concept of the apex (a), the apex of a younger person (b) and the changing apex due to hard tissue deposition (c).

(a) Position of the apical foramen (adapted from Kuttler 1955). (b) Anatomy of the root apex,

Anatomy of the apical foramen

 It is generally agreed that there are three distinct aspects of the apex that must be appreciated. Figure 1b shows these as the tooth apex (1), the apical foramen [major foramen (2)] and the apical constriction [minor foramen (3)] which is also described as the CDJ .

 The apical foramen is not always located at the anatomical apex of the tooth. The foramen of the main root canal may be located to one side of the anatomical apex, sometimes at distances of up to 3 mm in50 –98% of roots Dummer et al. (1984) reported the mean apex to foramen distance (Fig. 1b, 4) in anterior teeth to be 0.36

mm. The general trend is that the apex to foramen distance is greater in posterior teeth and older teeth than in anterior and younger teeth.

Anatomy of the apical foramen

 The foramen to apical constriction (Fig 1(b)5) is approximately 0.5 mm in the younger group and 0.8 mm in the older group for all tooth types   Traditional methods for establishing working length have been (a) the use of anatomical averages and knowledge of anatomy, (b ) tactile sensation, (c) moisture on a paper point and (d) radiography .Radiographic determination of working length has been used for many years. The radiographic apex is defined as the anatomical end of the root as seen on the radiograph, while the apical foramen is the region where the canal leaves the root surface next to the periodontal ligament ( American Association of Endodontists 1984).

Anatomy of the apical foramen

 When the apical foramen exits to the side of the root or in a buccal or lingual direction it becomes difficult to view on the radiograph.

 The preoperative radiograph is essential in endodontics to determine the anatomy of the root canal system, the number and curvature of roots, the presence or absence of disease, and to act as an initial guide for working length. The electronic apex locator is an instrument, which used with appropriate radiographs, allows for much greater accuracy of working length control

Apexlocators

 An electronic method for root length determination was first investigated by Custer (1918).

 Third generation apex locators are similar to the second generation except that they use multiple frequencies to determine the distance from the end of the canal. These units have more powerful microprocessors and are able to process the mathematical quotient and algorithm calculations required to give accurate readings.

 The relative values of frequency response method detects the apical constriction by calculating the difference between two direct potentials picked up by filters when a 1 kHz rectilinear wave is applied to the canal.

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Apexlocators

Many of the problems with previous generations of apex locators occurred when the root canal contained moisture rich substances such as exudate, electrolytes like sodium hypochlorite and the products of hemorrhage. The new third-generation apex locators these problems, are more user-friendly and require minimal calibration.

have overcome most of  More importantly is the revelation that modern-day apex locators may even be more reliable than radiographic interpretation. Studies evaluating apex locators demonstrated accuracies of working length determination to within 0.5 mm from the apical constriction, ranging from 75 percent to 93.4 percent. Nonetheless, using have today’s apex locator in conjunction with a radiograph is still an extremely effective adjunct for determining working length and detecting perforations or root fractures.

Apexlocators

 Current apex locators utilize an alternating current within the canal and monitor the impedance between periapical tissue and oral mucosa via a lip clip. The circuitry within the machine calculates the impedance between the file tip and lip mucosa; the apex is detected using the calculated impedance via needle pointers, sounds, lights, digital reads or various combinations thereof depending on the machine used.

Apexlocators

   New technology in this area has resulted in microprocessors that measure frequency shifts and apical capacitances.

As a result, accuracy of these locators has improved, especially in the presence of anatomical aberrations and canal moisture.

Examples of these include the Root ZX (J. Morita USA), the Justwo (Medidenta International) and the Endex (Osada Inc.). Some of these use an alternating current of at least two frequencies, and measure and compare the two electrical impedances.

Apexlocators

  This millennium is certain to deliver even more accurate apex locators , perhaps even totally eliminating working length images.

However, even if that goal is never attained, there are obvious advantages with the locators third-generation apex available today. These include an accurate working length determination, thereby reducing overall radiation exposure, as only a minimal number of images would be required. With accurate readings, there may be less chance for over- or underinstrumentation. Also, patient treatment time would be reduced as the result of the speed at which a length can be determined or verified.

Apexlocators

Apexlocators

Apexlocators

Root Canals not suitable for Electronic Measurement Reading (EMR) Root Canal with a large apical foramen

Root canal that has an exceptionally large apical foramen due to a lesion or incomplete development cannot be accurately measured; the results will show shorter measurement than the actual length.

Root Canal with blood, saliva or a chemical solution overflowing from the opening

If blood, saliva, or a chemical solution overflow from the opening of the root canal and contacts the gums, this will result in electrical leakage and an accurate measurement cannot be obtained. Wait for bleeding to stop completely. Clean the inside and opening of the canal thoroughly to get rid of all blood, saliva and chemical solutions and then make a measurement.

Broken crown

If the crown is broken and a section of the gingival tissue intrudes into the cavity surrounding the canal opening, contact between the gingival tissue and the file will result in electrical leakage and an accurate measurement cannot be obtained. In this case, build up the tooth with a suitable material to insulate the gingival tissue.

Fractured tooth Leakage through a branch canal

Fractured tooth will cause electrical leakage and an accurate measurement cannot be obtained.

A branch canal will also cause electrical leakage.

Re-treatment of a root filled with gutta percha

The gutta percha must be completely removed to eliminate its insulating effect. After removing the gutta percha, pass a small file all the way through the apical foramen and then put a little saline in the canal but do not let it overflow the canal opening.

Crown or metal prosthesis touching gingival tissue

Accurate measurement cannot be obtained if the file touches a metal prosthesis that is touching gingival tissue. In this case, widen the opening at the top of the crown so that the file will not touch the metal prosthesis before taking a measurement.

Cutting debris on tooth Pulp inside canal

Thoroughly remove all cutting debris on the tooth.

Thoroughly remove all the pulp inside the canal; otherwise an accurate measurement cannot be made.

Caries touching the gums

In this case, electrical leakage through the caries infected area to the gums will made it impossible to make an accurate measurement.

Blocked Canal

The meter will not move if the canal is blocked.

Open the canal all the way to the apical constriction to measure it.

Extremely dry canal

If the canal is extremely dry, the meter may not move until it is quite close to the apex. In this case, try moistening the canal with oxydol or saline.

Retreatment in endodontics

   Retreatment in endodontics provides a second chance for the patient to save the tooth that would otherwise be deemed for extraction.

Treatment approach can be either surgical or non surgical. Treatment failure can be due to many reasons from missed canal to iatrogenic perforation which has to be evaluated carefully before initiating the treatment.

Sometimes a clinician also has to deal with inter appointment fl are ups requiring prompt and effi cient patient management. This case report describes the non surgical management of failed root fi lled teeth which had also been treated surgically.

Conventional endodontic treatment may fail due to various reasons and inadequate root canal treatment with persistent infection remaining in inaccessible areas of the canal being one of them

Fig 1:

Clinical photo of the patient showing draining sinus

Fig 2:

Preoperative IOPA Radiograph

Fig 3:

After Gutta percha removal

Fig 4:

Immediate post obturation

Fig 5:

12 months recall

Fig 6:

24 months recall (decrease in size of periapical lesion is evident)

   If root fi lled tooth has failed, there can be fi ve possible treatment options: To review or do nothing, root canal retreatment, root end surgery, extraction followed by implant or referral. Cross sectional studies from different countries including most recent studies clearly demonstrate that more than 30% of all root fi lled teeth in the population are associated with apical periodontitis or post treatment disease9,10,11,12.

has been given by A general guideline European Society of Endodontology13 for indications of retreatment, they are; • Teeth with inadequate root canal fi lling with radiological fi ndings and/or symptoms • Teeth with inadequate root canal fi lling when the coronal restoration requires replacement • Teeth with coronal dental tissue that is to be bleached

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Conclusion

There is enough potential for success of primary root canal fi lling but fact remains that clinicians are confronted with post treatment disease.

Endodontic retreatment could be a suitable option in case of a post treatment disease following an endodontic failure.

Nonsurgical procedures could look of minor importance or insignifi cant during retreatment, for teeth.

managing surgical endodontic failure especially when reendodontic surgery appears inevitable. However, with non surgical treatment approach and adequate apical and coronal sealing we can achieve favourable clinical outcome even in case of failed surgically treated