Deposition vs. Root Canal

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Host's defense immune response is fundamental in this process. Pulpal or periapical inflammatory diseases are usually identified by the consequences of tissue aggressions. The main purpose of canal therapy is the removal of the causative - bacterial, chemical, mechanical and physical etiological - agents. Knowing the clinical factors associated with pulpal and periapical pain may provide important information for planing the therapeutic strategies and predicting RCT outcomes.

The most frequent diagnosis of pulpal pain has been associated with symptomatic pulpitis and hyper-reactive pulpalgia, and the most frequent periapical pain is symptomatic AP of infectious origin. Endodontic diagnosis and local factors associated with pulpal and periapical pain suggest that the important clinical factor in pulpal pain is closed pulp chamber and caries, and is periapical pain is open pulp chamber 3. Understanding the general clinical condition patient's systemic health and local clinical conditions of the tooth favors the first impression to predict a possible outcome of RCT.

The impact of patient's age, smoking status, initial treatment versus retreatment, root canal system exposed to salivary contamination prior to treatment, and the type of instrumentation on RCT outcome were recently evaluated 4. The integrity of a patient's nonspecific immune system, which has been neglected in earlier investigations, is a significant predictor for endodontic treatment outcome, and should receive more attention. The immune status of the patient, and the quality of the root filling showed a great influence on RCT outcome in a cohort study 4. Several non-endodontic diseases suggest a typical case of AP.

The differential diagnosis of diseases of non-endodontic and endodontic origin should always be made carefully. Radiolucent or radiopaque images in the mandibular or maxillary areas surrounding the root apexes may be a sign of non-endodontic disease, and may be misdiagnosed as AP 5 - 7. The periapical inflammation represents a natural biological defense response, caused by several etiologic agents. The model of the inflammatory response is similar in other parts of the organism.

The traumatic or infectious injury of the dental pulp is able to produce harmful consequences in the periapical region. The infection of the dental pulp mobilizes microorganisms to develop in apical direction, to invade and colonize the periapical tissues. The period of time of an infection process is unpredictable. Microorganisms with different characteristics structural, metabolic and pathogenic reaching the periapical region stimulate the inflammatory and immunologic responses. The organic defenses and the degree of virulence of the microorganisms establish several types of periapical alterations and its infection potential 8 , 9.

Some signs are solid evidence of the pathogenic potential to be neutralized by therapeutic strategies, like a tooth with root canal that remained open for some time and favored the invasion and colonization by different bacterial species, or the presence of a sinus tract, which collaborates with the invasion and development of a structured bacterial biofilm.

The participation of a bacterial complex in the process of pulp and periapical aggression has been thoroughly discussed in several studies 8 - Sundqvist and Figdor 13 reported that infection of the root canal is not a random event. The type and mix of the bacterial microbiota develop in response to the surrounding environment. Species that establish a persistent root canal infection are selected by the phenotypic traits that they share and that are suited to the modified environment. Nair 8 has defined pathogenicity as the ability of a microbe to produce disease and virulence; it is the relative capacity of a microbe to cause damage in a host Any metabolically active microbe living in the root canal has the potential to participate in the inflammation of periapical tissues.

Individual species in the endodontic microbiota may be of low virulence, but their survival in the necrotic root canal and pathogenic properties are influenced by a combination of several factors. They include the ability to build biofilms, interact with other microorganisms in the biofilm and develop synergistically beneficial partnerships, the capability to interfere with and evade host defenses, the release of lipopolysaccharides and other microbial modulins, and the synthesis of enzymes that damage host tissues 8 , 10 - 12 , 16 , The etiology of disease post-treatment in endodontics has been associated with microbial etiologic factors intraradicular and extraradicular infection — bacteria, fungi ; and nonmicrobial etiologic factors endogenous — true cysts; exogenous — foreign-body reaction 9 - 12 , According to Nair 8 , 10 - 12 , 16 , it is important to consider the extraradicular infections occuring by: Other etiologic agents should also be correlated as potential periapical aggressors.

The periapical inflammation may occur due to a natural defense response against over-instrumentation, over-irrigation or overfilling 18 - The root canal preparation and obturation should be restricted to the main root canal if there is no evidence contrary to this therapeutic protocol. The quality of root canal preparation and filling and coronal sealing are essential factors to achieve high rates of success, even in infected root canals.

This fact reinforces the concept of eliminating empty spaces that can harbor microorganisms 8 , 9 , 23 , Based on the need to control the microbiota of infected root canals, some aspects are necessary in a therapeutic protocol. Thus, the apical limit of instrumentation and obturation must be discussed, the determination of apical enlargement level anatomical diameter and the antibacterial efficacy of intracanal medicaments in root canal infections. Several studies reported that root canal preparation and obturation short of the radiographic apex were associated with a better prognosis 18 - The clinical characterization of apical morphology is extremely complex.

The root level of isthmuses and their frequency do not represent as standard 9 , The apical constriction and the apical foramen are not reliable anatomic landmarks for the obturation length at the apical end, and their use to calculate obturation length may result in injury to apical and periapical tissues On the basis of biologic and clinical principles, instrumentation and obturation should not extend beyond the apical foramen 18 - 22 , 27 - A frequent discussion in endodontic therapy, reported by Ricucci 30 and Ricucci and Langeland 31 concerns the apical limit of instrumentation and obturation.

The results of longitudinal studies, basic anatomical knowledge of the apical third of the root canal, and the histological pulp reaction to caries progression, demonstrated the presence of a vital apical pulp remnant, even in the presence of a periapical lesion. When there is pulp necrosis, bacteria and their by-products as well as infected dentin debris may remain in the most apical portion of the root canal, and these irritants jeopardize apical healing.

In these cases, highest success rates were achieved when obturation ended at 0—2 mm short of the radiographic apex. Systematic reviews 32 , 33 also showed that higher success rates are achieved when obturation is short of the apex root canal obturation mm short of apex. Thus, the filling material should remain confined to the root canal and in no way its presence beyond the apex is justified.

It is appropriate to remind that many injuries seem AP, but it does not mean they really are. The level of enlargement of the root canal and the action potential of disinfection process reflect the effectiveness of antimicrobial strategies. The estimate of the anatomic diameter of the root canal before enlargement should be considered 34 , Many instruments do not touch all canal walls Thus, root canal emptying and enlargement represent essential actions for antimicrobial control One of the challenges in RCT is to discover how to sanitize the isthmus areas that harbor microorganisms, which in turn prevents the action of the instruments on bacterial biofilm.

The antimicrobial efficacy of intracanal medicaments on bacterial biofilm is still not confirmed 24 , 26 , 37 , The selection of effective microbial control in infected root canals requires detailed knowledge of the microorganisms responsible for pulp and periapical pathology associated with understanding the action mechanism of the antimicrobial substances 39 , The success of infected RCT may be influenced by some clinical environments, as the planktonic suspension, presence of biofilm, time and type of infection, host response, and effective antibacterial therapeutic protocol.

Irrigant solutions are necessary during root canal preparation because they help to clean the root canal, lubricate the files, flush out debris, and have an antimicrobial and tissue dissolution effect, without damaging periapical tissues.

Determination of Working Length of Root Canal

The selection of an ideal irrigant depends on its action against the root canal microbiota and the biological effect on periapical tissue 24 , 25 , Several irrigating solutions have been considered in order to decrease endodontic infection and contribute to canal disinfection, including: However, up to now, sodium hypochlorite and chlorhexidine are the most often indicated antimicrobial agents for treatment protocols against endodontic and periodontal infections 24 , 25 , The antimicrobial effect of sodium hypochlorite by direct contact with E. The positive culture of microorganisms following the application of the irrigating solutions ozonated water, gaseous ozone, 2.

Thus, when a medicament does not reach the target microorganism, its killing potential cannot be recognized. Therefore, it cannot be stated whether the microbial strains were resistant to one or other medication. In this case, it is likely that the microorganisms were able to survive, adapt and tolerate the critical ecological conditions. In the same direction, the properties of calcium hydroxide stem from its dissociation into calcium and hydroxyl ions and the action of these ions on tissues and bacteria explains biological and antimicrobial properties of this substance Thus, it was shown that calcium hydroxide induces the deposition of a hard tissue bridge on pulpal and periodontal connective tissue 41 - Its action on connective tissue pulpal and periodontal tissues revealed the ability to stimulate mineralization, from the significant involvement of alkaline phosphatase and fibronectin 39 - There is a great release of hydroxyl ions from calcium hydroxide, which are able of altering the integrity of the bacterial cytoplasmic membrane through the toxic effects generated during the transfer of nutrients or by the destruction of the phospholipids of unsaturated fatty acids.

The influence of pH alters the integrity of the cytoplasmic membrane by biochemical injury to organic components proteins, phospholipids and transport of nutrients. The maintenance of a high concentration of hydroxyl ions can change the enzymatic activity and provide its inactivation In addition, the healing process in teeth with AP after RCT in two appointments with the use of calcium hydroxide paste showed a better status of periapical tissue with mineralized barrier 43 - The presence of biofilm in the root canal system is a challenge to the outcome of RCT 26 , The active participation of mechanical action of endodontic instruments combined with antimicrobial strategies appears to be crucial for decreasing root canal infection.

The estimation of the RCT prognosis must be related to criteria for understanding the success. This aspect implies in evaluating results based on longitudinal monitoring, which requires a standard. The RCT success criteria and its prevalence should be routinely reevaluated. AP is a consequence of root canal system infection, which can involve progressive stages of inflammation and changes of periapical bone structure, resulting in resorptions identified as radiolucencies in radiographs RCT failures may involve microbial and non-microbial factors, as discussed previously 9 - 12 , A high rate of failure is associated with endodontically treated teeth associated with AP, overfilling, and teeth that were not properly restored after RCT 18 - 22 , 27 , 47 - Thus, utmost care must be taken to establish criteria to define success.

On this account, the life of a tooth endodontic treatment may be rely on the time and the age of the individual. In a prospective analysis, an endodontically treated tooth is expected to remain throughout the individual's life. It is important to recognize that along people's life, some diseases may develop and impact their health. Incidentally, an infection or re-infection may arise some time after RCT.

To characterize the outcomes of endodontically treated teeth with vital pulp healthy or inflamed pulp , infected pulp, AP and periapical abscess, must be considered the time since RCT conclusion and the definite restoration. The previous status of pulp and periapical tissue may aid in the interpretation of actual clinical conditions. Strindberg 50 described important clinical and radiographic factors associated with RCT success and failure. A considerable number of clinical studies have discussed the causes of failure of endodontically treated teeth and prospects for prognosis in retreatment 50 - The correlation of RCT failure with infected root canal was evident in several conditions 1 , 3 , 8 - 20 , 24 - 27 , 35 - 40 , 47 - Traditionally, three aspects are associated in the analysis of RCT success — the clinical, radiographic and microscopic characteristics.

In the clinical context, two of these aspects normally guide the decision-making process: The cases of doubt on the success or failure involve a transition phase and definition of criteria may be imposed by the limitations of the used clinical or imaging exams. Clinical success and clinical silence are different aspects to be analyzed. Clinical failure may present or not a symptomatic pain condition. In this sense, AP cannot be correctly identified by periapical radiography only. The experienced professional has many resources to identify the agent responsible for the failure.

Notwithstanding the dentist's skills, the diagnosis of odontogenic pain should always follow an accurate protocol, since the pain felt by the patient may not have a direct association with a well or bad endodontically treated tooth. Various factors may affect tooth survival, such as dental caries, periodontal disease and RCT. The prevalence of endodontically treated teeth associated or not with AP has been examined in several populations 1 , 48 , 49 , 61 , 72 , Regarding the prevalence of endodontically treated teeth in Brazilian adults, a previous study showed that in a sample of 29, teeth, only 6, RCT was most frequent in maxillary premolars and molars, whereas mandibular incisors showed the lowest prevalence.

Most endodontically treated teeth were found in people aged 46 to 60 years A total of 1, periapical radiographs of endodontically treated teeth by postgraduate students were evaluated 1. AP prevalence was significantly higher in teeth with poor endodontic treatment Prevalence of AP was also higher in teeth with poor coronal restoration Based on periapical radiographs, the prevalence of AP was low when associated with a high technical quality of RCT.

In health sciences, such as endodontics, various advances were applied to clinical practice. The therapeutic assessment of dental treatment by computed tomography characterizes a sensible advance of information in health 76 , This contribution may be applied to planning, diagnosis, therapeutic process and prognosis of several diseases.

The continuous advance of technology enabled the development of cone beam computed tomography CBCT 78 , 79 , which has widen numerous perspectives for application in different research areas and clinical dentistry 80 - Imaging resources have been routinely used before, during and after dental treatment. Conventional radiographic images provide a two-dimensional rendition of a three-dimensional structure, which may lead to interpretation errors.

Periapical lesions of endodontic origin may be present but not visible on conventional 2D radiographs 80 - The accuracy of diagnosis is a critical factor for the success. The correct management of CBCT images may reveal abnormalities unable to be detected in periapical radiography and may enhance a more predictable planning and treatment 80 - The possibility of a map-reading approach with CBCT images reduces the problems related to difficult evaluation conditions that require special care during diagnosis In view of the limitations of periapical radiography to visualize AP, a review of epidemiologic studies should be undertaken considering the quality of periapical aspects provided by CBCT images.

It will certainly reduce the influence of radiographic interpretation, with less possibility for false-negative diagnoses. AP prevalence in endodontically treated teeth, when comparing the panoramic and periapical radiographs and CBCT images, was A considerable discrepancy can be observed among the imaging methods used to identify AP. AP was correctly identified in Minor changes in sensitivity were found for different teeth groups, except for incisors in panoramic radiographs.

ROC analysis suggests that AP is correctly identified with conventional methods in an advanced stage. In teeth where the small size of the existing radiolucency was diagnosed by radiographs and considered to represent periapical healing, enlargement of the lesion was frequently confirmed by CBCT. In clinical studies, two additional factors may have further contributed to the overestimation of successful outcomes after root canal treatment: The outcomes of root canal treatment should be re-evaluated in long-term longitudinal studies using CBCT and stricter evaluation criteria.

Characteristics of the clinical and imaging outcomes from RCT include: In case of doubt, it is essential to discuss the clinical case with a more experienced professional, as in some cases it is not easy to determine the differential diagnosis of diseases of non-endodontic and endodontic origin. Various radiolucent images may be associated with the apex, without being diseases of microbial origin and could be misinterpreted as AP 5 - 7. The time to start the treatment is also a key factor to determine success or failure.

The possibility of map-reading in CBCT images minimizes several problems related to complex diagnosis, particularly in dubious cases. A strategy to minimize metallic artifact in root perforation associated with intracanal post is to obtain sequential axial slices of each root, with an image navigation protocol from coronal to apical or from apical to coronal , with 0.

This map reading provides valuable information showing dynamic visualization toward the point of communication between the root canals and the periodontal space, associated with radiolucent areas, suggesting root perforation. Operative procedural errors OPE may occur and they represent risk factors able to compromise a tooth 86 , Errors characterize disability, non-observance of therapeutic protocol and low level of knowledge involving the endodontic principles.

Deficient attendance may be responsible for severe consequences and sequels, which impairs the prognosis, and may result in serious judicial questions In endodontically treated teeth, OPE included underfilling, overfilling, and root perforation; OPE in dental implants were thread exposures, contact with anatomical structures, and contact with adjacent teeth.

Underfilling, overfilling, and root perforations were detected in Dental implants with thread exposures, contact with important anatomical structures and contact with adjacent teeth were seen in OPE were detected in endodontically treated teeth and dental implants, and underfilling and thread exposures were the most frequent occurrences, respectively. The extension of treatment in a tooth with indication for extraction can be a dental implant.

The problem of replacing a biological structure by biocompatible materials requires care and precise indication. Information about criteria and rates of success in endodontically treated teeth and dental implants are of utmost importance. It appears that few high-level studies have been published in the past four decades related to the success and failure of nonsurgical root canal therapy.

The data generated by this search can be used in future studies to specifically answer questions and test hypotheses relevant to the outcome of nonsurgical root canal treatment. The current moment of endodontic science is promising in view of all the knowledge acquired over the last few years New technologies such as CBCT influenced the quality of diagnosis, planning, therapy and longitudinal control. A wide array of endodontic instruments for safer root canal preparation was introduced in endodontics. Some of these advances contributed to the revision of concepts, and to determine adjustments to the treatment protocol.

One concern discussed at meetings in endodontics and in several recent studies 80 - 86 relates to overestimated numbers of success in RCT. Depending on the dentist's knowledge and skills for interpreting CBCT images, higher percentages of errors and failures in RCT may be identified. The possibility of map-reading on the CBCT scans can characterize the reality of a multidimensional structure, aiding with precise information the presence, absence or regression of AP.

The life of an endodontically treated tooth implies understanding the biological and mechanical results as a multifactorial event, over the life span of the individual.

The authors deny any conflicts of interest related to this study. This obviously led to multiple errors. If vital tissues were left in the canal, the calculation would be too short. If a periapical lesion were present, the calculation would be long.

Radiographs in dentistry came about in However, the thought at that time was that the dental pulp extended through the tooth, past the apical foramen, into the periapical tissue and that the narrowest portion of the tooth was at the extreme apex. The radiographic apex was thought to be the correct site to terminate the canal preparation. In the 's, Blaney and Coolidge offered information that indicated that filling slightly short of the root tip gave the best results. In , Kuttler gave the most comprehensive anatomic microscopic study of the root tip.

He studied several thousand teeth. Not everyone embraced his ideas initially but over the past 40 years his ideas are still practiced. In individuals between the age group of 18—25 years, the average distance between the minor and major diameters was 0. In older individuals the average distance was 0.

Introduction

Therefore Kuttler felt that it was an unwise clinical procedure to fill to the radiographic apex because it caused postoperative pain and lowered the success rate. Many studies have followed and supported Kuttler's findings. In , Ingle used the pre-treatment radiograph in a mathematical procedure for determining working length.

The original tooth image was measured on the pretreatment radiograph, following substraction of a standard 2—3 mm from that length to compensate for distortion. There are several ways to determine the working length of the root canal viz radiographs, electronic apex locators, tactile sense, patient response, knowledge and experience, predetermined normal tooth length, use of paper points, mathematical equations etc. Accuracy in length determination is necessary to avoid damage to the apices of teeth and to the periapical tissues during instrumentation, thus providing better conditions for healing after endodontic treatment.

As with anything that is open to interpretation, variation exists in the radiographic determination of endodontic file length. The advantage of apex locators are that they are supposedly accurate, easy, fast and reduce exposure to radiation. Artificial perforation can be recognized and it is the only method that can measure length to the apical foramen and not the radiographic apex.

The disadvantages are that it requires a special device and accuracy is influenced by electrical condition of canal.

Characterization of Successful Root Canal Treatment

Most of the disadvantages come from the fact that the magnitude of the impedance of the canal is influenced by the electrolytes present inside the canal. Electronic apex locators have limitations in teeth with wide open apex. Ratio method measures the impedance of two different frequencies, calculates the quotient of the impedances and expresses this quotient in terms of the position of the electrode file inside the canal.

The quotient is hardly affected by the electrical condition inside the canal. No calibration is needed. With this device one can use fine endodontic files without the need to precalibrate the circuit before locating the apical foramen. Metallic restorations and heavily calcified canals interfere with electrical conductivity. With heavily calcified canals, patency of the canal needed to be established before determining the electronic signal of the apical foramen. With an electronic method one can always detect electrically the point where the file tip is in contact with the periapical tissue tissue fluid even if the apical foramen is located away from the anatomic apex.

To keep the canal enlargement within the canal, the actual working length is slightly less than the measurements. The best working length is found by subtracting approximately 0. It is important to know that there is potential for interference of an electronic apex locator with a patient's cardiac pacemaker function. It depends on the specific type of pacemaker placed and the patient's dependence on it.

It is best to consult the patient's cardiologist before the treatment. The IndMED database is accessible on internet at the website http: Bibliographic details of the journal are available on the website http: At present you will find full text articles from the year at http: Articles can also be searched directly at www. Authors Index, Subject Index and contents of the volume appear in October issue every year. National Center for Biotechnology Information , U. Med J Armed Forces India. Published online Jul Author information Article notes Copyright and License information Disclaimer.

Received Jun 23; Accepted May 5. Abstract Background This study was undertaken to determine the working length of root canal by microprocessor controlled impedance quotient apex locator and conventional radiographic method. Methods Patients whose teeth were to be extracted were selected for this study. Result It was observed that the radiographic method had a significant variation from the electronic method when compared to the actual measurement on the extracted tooth. Conclusion The electronic method is a more accurate method as compared to radiographic method for determination of working length of the root canal.

Working length, Root canal, Cementodentinal junction, Electronic apex locators. Introduction The explicit location of the physiological apex of root canal is a prerequisite for a successful endodontic therapy. Open in a separate window. Material and Methods Patients whose teeth were to be extracted were selected for this study.

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Root ZX probe attached to file to determine working length of root canal. Results The purpose of the present study was to compare the accuracy of frequency based apex locator Root ZX and conventional radiographic method under clinical conditions. Discussion Most experts agree that the canal preparation should terminate at the CDJ.

Conclusion From the results of the present study it may be concluded that 1. The Root ZX electronic device was able to predictably locate the minor diameter to within 0. The results show that the electronic root canal length measurement devices are a useful adjunct to endodontic practice. Further studies should be performed to evaluate the effect of diameter of apical foramen on the electronic root canal length measurement devices and also the ability of these devices to locate apical constrictions, perforations, horizontal and vertical fractures. Within the limitations of the study the radiographic method was standardized and the long cone was used but some element of variation may have been there in the radiographic readings which may have influenced the results.

Further studies using a larger sample size and standardized radiographic methods are recommended. Intellectual Contribution of Authors Study Concept:

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