Retrograde approaches in endodontic therapy

Abstract The routine use of retrograde fillings during apical surgery, as well as the material of choice for that purpose, have been debated. A retrograde filling is placed so as to seal an infected root canal causing periapical pathosis. Therefore, retrograde root canal fillings should be performed routinely during apical surgery regardless of the apparent technical quality of the root canal obturation, unless orthograde endodontic treatment is performed in conjunction with surgery. When orthograde treatment is not performed in conjunction with surgery. When orthograde treatment is not performed, retrograde root canal filling enhances the prognosis of apical surgery. An array of potential retrograde filling materials have been extensively investigated in vitro and in vivo. Once that the biocompatibility of the materials is confirmed a clinical comparison, rather than in vitro sealability studies, is the most valid evaluation method. Some of the difficulties encountered in long term clinical studies in patients may be avoided in animal studies. The review of the relevant literature of the past decade suggests that amalgam used in conjunction with cavity varnish is the retrograde filling material of choice. It must be stressed, however, that retrograde filling is not comparable to debridement and obturation of the entire root canal. Therefore, when the only way to approach the root canal is from the apical direction, rather than placing an apical retrograde filling, a retrograde endodontic treatment of the entire canal should be preferred, if it is feasible.     

Chamberless Endodontic Access for Treatment of Calcified Anterior Central Incisors

IntroductionModern techniques for treating maxillary anterior central incisors with calcified canals emphasize maintaining coronal dentin with small crown access. Alternatively, traditional retrograde surgical procedures are focused on creating an apical seal predominately limited to the remaining resected apical one third of the root canal space. A treatment option for calcified anterior teeth, with avoidance of traditional orthograde access, is presented. Chamberless endodontic access (CEA) to the canal is chosen in this case, leveraging a previous surgical treatment and osseous defect to create straight line canal access.MethodsA tooth presenting with a chronic apical abscess and an apparent previous apical surgery was instrumented and obturated using a CEA avoiding the traditional orthograde approach to the root canal system. Straight line approach was achieved retrograde and canal instrumentation was performed using ultrasonic activated U-files. Canal obturation was accomplished with warm vertical condensation technique followed by placement of an apical retroseal.ResultsA successful 52-month outcome demonstrated the viability of CEA facilitating retrograde instrumentation and obturation.ConclusionsUse of CEA simultaneously protected the clinical crown and provided a successful clinical outcome. A viable option for treatment of an anterior calcified canal and abscess due to dental trauma, CEA mitigates many of the risks associated with the treatment of calcified root anatomy.     

Long-term survival of teeth in the posterior region after apical surgery

Oftentimes the discussion of long-term success rates and treatment modalities becomes a central issue in consultations with patients. The aim of this study was to retrospectively evaluate survival rates of teeth after apicoectomy in an established private practice for Oral and Maxillofacial Surgery in Kiel, Germany.All teeth treated with apicoectomy between 2001 and 2006 were included. Treatment success was previously defined as preservation of the tooth. Putative influence factors on success as kind and quality of endodontic treatment, additional intraoperative endodontic filling, inflammatory status, tooth mobility, and pre- and postoperative X-rays were further evaluated.A total of 149 teeth could be included. The mean observation period was 6.3 (SD: 4.4) years. In all, 48.3% of these teeth could be retained after a 10-year period. Teeth that received an additional retrograde root canal filling during surgery resulted in a significantly higher success rate (p = 0.0237) compared to those with orthograde root canal fillings or without additional endodontic treatment. The quality of endodontic treatment had no impact (p = 0.125).Our results suggest that apical surgery is a reliable procedure to treat and ensure the survival of symptomatic teeth in the posterior region for several years. A significant improvement was further determined for a retrograde filling.     

Timeliness and effectiveness in the surgical management of persistent post‐treatment periapical pathosis

Common problems that cause persistent post‐treatment periapical pathosis include infection remaining in the apical inaccessible areas, extraradicular infection including apically extruded dentine debris with bacteria present in dentinal tubules, radicular true cysts, foreign body reactions, inadequate non‐surgical root canal treatment with or without iatrogenically altered root canal morphology, and vertical root fractures. Inadequate root canal treatment may be corrected non‐surgically, while more complex problems may require surgical intervention. The important factors that warrant a successful surgery include good quality of the orthograde root canal treatment, deep retrograde preparation of the apical canal, and carefully cleaning and filling of the exposed isthmuses and accessory canals. Ideally, apical surgery and orthograde retreatment are performed simultaneously. In a recent study, 97% of the lesions including large ones of >10 mm in diameter healed completely within 1 year after surgical intervention. Of the teeth that showed ‘complete healing’ at 4 years more than 85% already ‘completely healed’ at 2 years; thus, the endodontic post‐treatment disease might be treated surgically or non‐surgically within 2 years after the previous treatment.     

The prognosis and expected outcome of apical surgery

Clinicians should possess current knowledge about the prognosis and expected outcome of endodontic treatment, including apical surgery. This knowledge cannot be acquired by indiscriminate review of the many available studies because they vary in the level of evidence they provide. Therefore, seven studies that best comply with methodology criteria defining the levels of evidence were selected and used as the basis of this review. In spite of their methodological consistency, the outcomes reported in these studies still differ considerably, mainly because of differences in inclusion criteria. According to these studies, 37–91% of teeth can be expected to be healed, while up to 33% can still be healing several years after surgery. Importantly, 80–94% of teeth can remain in symptom‐free function, even if they are not healed. Several pre‐operative factors may influence the outcome of treatment; the outcome may be better in teeth with small lesions and excessively short or long root canal fillings, and it may be poorer in teeth treated surgically for the second time. With regard to intra‐operative factors, the choice of the root‐end filling material and the quality of the root‐end filling may influence the outcome, while the retrograde retreatment procedure clearly offers a better outcome than the standard root‐end filling. In summary, the expected outcome of apical surgery is good and therefore, before considering tooth extraction and replacement, apical surgery should be attempted when it is feasible.     

The Effect of Mineral Trioxide Aggregate Obturation Levels on the Outcome of Endodontic Retreatment: An Observational Study

IntroductionNo clinical studies have examined the effect of mineral trioxide aggregate (MTA) obturation levels on the outcome of endodontic retreatment. This retrospective study examined treatment outcomes in three cohorts that compared overfilling, flush filling, and underfilling after orthograde retreatment using MTA.MethodsTwo hundred fifty patients with 264 teeth diagnosed with previously treated root canals and apical periodontitis retreated in a private endodontic practice were included. All teeth received MTA obturation and the extent of the final filling level was measured in relation to the major apical foramen. After 6-month follow-ups, all nonhealing cases were treated surgically. After 24- to 72-month reviews, the effect of preoperative lesion size and the degree of MTA obturation level were assessed. Multiple linear regression and time-to-event analysis using Stata 17 software (StataCorp LLC, College Station, TX) were used to evaluate the data.ResultsWithin the three cohorts, 99 out of 108 overfilled teeth (91.7%), 90 out of 103 flush fills (87.4%), and 10 out of 53 underfilled teeth (18.9%) healed and were successfully retreated without surgery at 48-months. When surgical outcomes were included, the combined healed proportion was 93.2%. Preoperative lesion size was found to be an important predictor for retreatment nonhealing. A 1-mm increase in lesion size at baseline resulted in an estimated 11% (95% CI 1.04, 1.18)–38% (95% CI 1.22, 1.58) increase in the risk of surgery. Compared to overfilling and flush filling, underfilling was associated with an approximately three-fold increase in requiring surgery and characterized by delayed healing.ConclusionMTA obturation is a viable retreatment option for teeth with nonhealing endodontic treatment. MTA overfills or flush fillings do not adversely affect healing outcomes. However, MTA underfilling increases the chances for nonhealing and surgical intervention.     

Orthograde retreatment and apexification after unsuccessful endodontic treatment, retreatment and apicectomy

AIM: To describe a case where a second orthograde retreatment was successful in the management of an infected mandibular right first molar that previously had received both orthograde and retrograde treatments. SUMMARY: Periapical surgery is unlikely to be successful unless the root canal system has been adequately debrided and sealed. A case is described where orthograde endodontic treatment, retreatment and apicectomy were unsuccessful in the management of and infected mandibular right first molar. The periapical radiolucency eventually disappeared following a second orthograde retreatment. Teh second retreatment included 12 months of intracanal calcium hydroxide placement to promote apexification, thus allowing subsequent controlled obturation with gutta percha and AH26. At a 5-year review following completion of treatment, the tooth remained asymptomatic and was in normal function. KEY LEARNING POINTS: Orthograde retreatment is a treatment option to manage refractory lesions in teeth that have previously received endodontic treatment, retreatment and apicectomy. Orthograde retreatment using long-term intracanal calcium hydroxide can help promote root-end closure of a resected apex.     

根尖倒充填术后根尖微渗漏的影响因素

根尖倒充填术后根尖发生微渗漏是导致根尖手术失败常见的原因之一。根尖倒充填术后根尖微渗漏的影响因素有很多,包括根尖切除方法及根尖窝洞预备,对根尖牙本质表面的处理,不同的根尖倒充填材料,以及根管是否充填和pH值等。本文对此作一综述。     

Ultrasonics in endodontic surgery: a review of the literature

Currently, although ultrasonics (US) is used in dentistry for therapeutic and diagnostic applications as well as for cleaning of instruments before sterilization, its main use is for scaling and root planing of teeth and in root canal therapy, both for orthograde and retrograde therapy. Both in conventional and surgical treatments, US in endodontics has enhanced quality of clinical procedures and represents an important adjunct in the treatment of difficult cases. More precisely it has become increasingly more useful in applications such as gaining access to canal openings, cleaning and shaping, obturation of root canals, removal of intracanal materials and obstructions, and endodontic surgery. This review of the literature aims at presenting the numerous advantages of US in surgical endodontics and emphasizes its application in a modern-day endodontic practice.     

A systematic review of in vivo retrograde obturation materials

Purpose The aim of this study was to answer the question: For patients requiring apicoectomy (apicectomy/root‐end resection) and retrograde (root‐end) obturation (filling), which retrograde obturation (root‐end filling) material(s) is/are the most effective, as determined by reduction in periapical radiolucency and elimination of signs and symptoms? Materials and methods A MEDLINE and a Cochrane search (two specified searches) were conducted to identify randomised (RCT) and nonrandomised controlled clinical trials (CCT), cohort studies (CS) and case‐control studies (CCS), published between 1966 and 2002, October week 4, conducted on humans, and published in English, German and French language, relating to retrograde obturation materials following apicoectomy. Results The MEDLINE and the Cochrane search identified 324 and 21 published articles, respectively. The Cochrane search identified three additional articles to the MEDLINE‐search articles. Fourteen studies met the inclusion criteria: two were RCTs, six were CCTs, none was a CS and six were retrospective CCSs. Nine of the 14 studies compared a new retrograde (root‐end)‐filling material to amalgam, 4 of the 14 studies compared orthograde root canal fillings to retrograde (root‐end) amalgam and the fourteenth study compared variations of a resin composite (Retroplast) when used in combination with the bonding agent Gluma (Bayer AG, Gluma 1 and 2). The two RCTs indicated that glass ionomer cement appeared to be equivalent to amalgam. The six CCTs indicated that orthograde filling with gutta‐percha and sealer was more effective than amalgam retrograde (root‐end)‐filling (one trial). Similarly, retrograde (root‐end)‐filling with (i) composite and Gluma (Bayer AG, Leverkusen, Germany) as bonding agent (one trial), (ii) reinforced zinc oxide eugenol cement (EBA cement) (Stailine, Staident, Middlesex, England; one trial) and (iii) gold leaf (one trial) appeared to be better than amalgam retrograde (root‐end)‐filling. Finally, gutta‐percha retrograde (root‐end)‐filling appears to be less effective than amalgam (one trial) and Retroplast with ytterbium trifluoride is better than Retroplast with silver, when they are both used with Gluma as bonding agent (one trial). Conclusions For the highest level of evidence (RCT) retrograde (root‐end)‐filling with glass ionomer cement is almost as effective as amalgam. However, there was a significant caveat as there were only two RCTs. At the next highest level of evidence (CCT), and given the additional caveat that there was only one controlled trial for each material, retrograde (root‐end) EBA cement, composite with Gluma and gold leaf, as well as orthograde gutta‐percha, may be more effective than retrograde (root‐end) amalgam filling. In conclusion, these results suggest that additional validating CCTs and RCTs are needed.     

Un approccio critico alle tecniche di otturazione canalare

AimThe root canal obturation is one of the most important phases of the endodontic treatment. In fact, it will have the important task of creating an airtight and three-dimensional seal of the root canal system thus preventing the percolation of periapical fluids and of neutralizing the microorganisms survived after the procedures of cleaning and shaping. Many obturation techniques have been suggested and choose the most appropriate according to the treatment plan can be difficult. The purpose of this article is to describe indications, limitations and operating sequences of the most popular techniques for root canal filling.MethodologyOver 130 articles on Medline were selected, all on the topic of the root canal obturation. The studies, chosen following the requirements of the “evidence based medicine”, were divided into clinical studies, studies in vitro and case reports and matched in a comparative analysis to identify advantages and limitations of the methods considered.ResultsWhen considering the clinical studies on the long-term outcome, there are no significant differences in the success rates obtainable with the different methods. On the contrary, there is a strong scientific evidence that demonstrates a superior capability of the techniques based on thermo-plasticized gutta-percha of filling three-dimensionally even the most complex root canal systems with a reduced amount of sealer.ConclusionsThe root canal filling techniques based on the vertical condensation of warm gutta-percha show a greater ability of creating airtight fillings. The choice between them will depend on the characteristics of the clinical case. In the long and curved root canals it will be advisable to use the carrier-based techniques that result easier and that allow a more conservative root canal preparation, whereas the techniques of continuous wave or the classic Schilder technique will give better results in straight or wide canals or in case of internal resorptions.     

Periapical status, quality of root canal fillings and estimated endodontic treatment needs in an urban German population

Abstract The objective of this study was to determine the periapical status and the quality of root canal fillings and to estimate the endodontic treatment needs in a German population. Clinical and radiographic data and the operative procedures performed were evaluated on 323 patients coming to a dental surgery in Stuttgart, Germany, in 1993. In 182 individuals at least one tooth exhibited a root canal filling, a necrotic pulp or an irreversible pulpitis. Out of the 7897 teeth examined, 215 (2.7%) had a root canal treatment (category A), 122 being nonendodontically treated (1.5%) did not respond to the sensitivity test (category B) and 53 (0.7%) were diagnosed as having irreversible inflamed pulp tissue (category C). The prevalence of teeth associated with radiographic signs of periapical pathosis was 61 % in the group of root canal filled teeth and 88% in the group of pulpless and non-endodontically treated teeth. Using the level and the density of the root canal filling as criteria for evaluating the technical standard, only 14% of the endodontic treatments of non-apicectomized teeth were qualified as adequate. The minimal endodontic treatment need is 2.3% related to all examined teeth when the root canal filled teeth with clinical symptoms of periapical periodontitis (category A) and those of categories B and C are included. The real endodontic treatment need is suggested to be larger when considering that the technical quality of the obturation is poor in most symptomless endodontically treated teeth associated with a periapical lesion. In the case of retreatment of these teeth, the endodontic treatment need would then be calculated at 3.7%.     

Il ruolo della strumentazione meccanica nei ritrattamenti endodontici

Objectives

Endodontic retreatments are performed when endodontic therapy fails and the tooth is considered restorable. They include orthograde, surgical, and combined approaches. The primary objective of orthograde retreatment is the complete removal of the old filling material from the root canal. The purpose of this paper is to describe an orthograde endodontic retreatment technique performed with specific mechanical instruments made of nickel-titanium (NiTi).

Materials and methods

For retreatment, the root canal filling can be removed with traditional methods, such as heat carriers, Largo or Gates burs, and hand-held steel instruments, or newer methods, such as ultrasonic inserts, laser tips, and NiTi files (manual or mechanical). The orthograde retreatment technique presented here uses specific NiTi endodontic rotary instruments (Mtwo R^®). We describe its use in two cases involving retreatment of teeth 4.6 and 2.5, whose root canals had been filled using thermoplastic gutta-percha, plastic carrier and endodontic sealer, and a single gutta-percha point.

Results and conclusions

The success of orthograde endodontic retreatment depends on many factors, including correct and complete removal of old filling material from the root canal. The specific NiTi endodontic rotary instruments (taper .05) we used are very sharp at the level of the blades and the tip, and they allow rapid, safe removal of commonly used endodontic filling materials, even in the presence of a plastic carrier. As illustrated by the two cases presented, we used NiTi endodontic rotary instruments specifically designed for retreatment in the coronal two thirds of the canal, manual instruments in the apical third, and simultaneous technique after the filling material had been removed. This approach allowed acceptable preservation of the original anatomy of the canal and effective sealing by the new filling material.     

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

Aim  To investigate the technical feasibility and outcome of retrograde root canal treatment.
Summary  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.
Key learning points • 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.     

Effect of root-end resection and root-end filling on apical leakage in the presence of core-carrier root canal obturation

AIM: To evaluate the apical seal of canals filled with a core-carrier obturator following root-end resection with and without a root-end filling. METHODOLOGY: Thirty single-rooted human teeth with single canals were used. Root canal treatment was performed and canals filled with a core-carrier obturation technique. The teeth were then randomly assigned to three groups (n = 10). In the first group root canal filling only was performed. After orthograde filling, the teeth of the second group were resected apically, perpendicular to the major axis of the root. In the third group after apical resection, a root-end cavity was prepared using ultrasonic diamond retrotips and the cavities filled with Super-EBA cement. During a period of 3 h and with a headspace pressure of 0.12 atm, methylene-blue solution was forced through a tube that was connected to the apical end of each tooth specimen. The coronal end of the tooth was connected to a capillary tube containing an air bubble. Leakage was evaluated by observing the distal displacement of the air bubble. The roots were then sectioned along their long axis. Using a stereomicroscope, linear dye infiltration at the dentine-cement interface was determined. Kruskal-Wallis and Mann-Whitney tests were used to compare the three groups. RESULTS: Linear dye infiltration was significantly greater in root canals filled with the core-carrier obturators and resected apically (0.9 +/- 0.9 mm) when compared with those that had root-end fillings (0.2 +/- 0.4 mm). Air bubble displacement was not observed. CONCLUSION: Root-end filling improves the sealing of roots with core-carrier obturation following root-end resection.     

Anatomic determination of the mesiobuccal root resection level in maxillary molars

Surgical endodontics involving root resection/apical fill are often performed when retreatment by orthograde endodontic procedures are not possible. Because of the potential presence of accessory canals within the root, a preferred minimal root resection level should be investigated for the removal of the majority of these canals. One hundred fifty-three extracted, uninstrumented, mesiobuccal roots from first and second maxillary molars were examined for the presence of accessory canals, canal isthmus, and canal wall thickness. Three hundred ninety accessory canals were identified, with 80% of these canals located within 3.64 mm of the apex of the tooth. Canal isthmus was often not evident until 3.12 mm of the root was resected, with canal wall thickness only approximating 1 mm thick. The observations here suggest a minimal resection level to 3.6 mm for accessory canal incidence, canal isthmus detection, and canal wall thickness and provide a better understanding of maxillary mesiobuccal (MB) root anatomy for retrograde root resection/apical filling.     

Development of a Basic Root canal Treatment (BRT) for primary oral health care — evaluation after one year

Objectives : Atraumatic Restorative Treatment (ART) was a major step forward in community dentistry but treatment options for deep carious lesions or pulp involvement still focus on tooth extraction in under‐served areas worldwide. To bridge the gap between ART and extraction this pilot study aimed to develop and follow‐up a basic root canal treatment for rural dental health facilities in the Republic of The Gambia (West Africa), faced with an environment lacking technical equipment and developing primary oral health care. Methods : 25 single rooted teeth with acute irreversible pulpitis were root canal treated with a standardised endodontic instrument kit and a specific procedure. A step‐back technique was used with intermittent chlorhexidine 0.2% and saline irrigation. Root canal obturation was performed using a single‐cone technique with gutta‐percha using Grossman's root canal cement. Coronal filling was carried out by using ART. Clinical examinations were documented before treatment, one day, five days, six months and twelve months postoperatively. Results : None of the root canal fillings had to be revised due to postoperative complications. In 9 out of 25 teeth, transitory apical pain disappeared after a few days. After six months, all ART fillings appeared clinically acceptable, two fillings had to be corrected. Four class II restorations and three class IV restorations needed replacement after 12 months. Patients' assessment of health related quality of life improved significantly, especially concerning dental pain, chewing ability and fitness for work. Conclusions : Preliminary clinical follow‐ups showed encouraging results for the basic root canal treatment approach. Longitudinal clinical studies with greater populations are required to substantiate these results. Modifications in the coronal filling technique are preferable to improve the clinical performance of extended ART cavity restorations.     

��֧���ܳ���

??Root canal obturation is one of the difficulties in endodontic therapy procedure. It requires complete removal of pathogenic stimuli and complete obturation. Lateral canals of the main root canal are occur more commonly in the apical portion??leaving a small gap to reach the periodontal ligament. Because of the high incidence of lateral canals and other lateral accessory canals which are difficult to clean??the influence of lateral canals and apical ramifications on treatment outcome has long been given attention to by clinicians and researchers. Thermoplasticized gutta-percha filling technique has showed prominent advantages in lateral canal obturation in many studies??but there has been no clear clinical evidence as to this matter. The anatomy and obturation techniques to lateral canal and the necessity of obturation were introduced in this article.     

Utilization of gutta-percha for retrograde root fillings

Just as gutta-percha used with a root canal sealer is a recommended material for orthograde root fillings, it could similarly be the material of choice for retrograde fillings. Unfortunately, clinical accessibility and visibility do not always facilitate such a technique. The aim of this article is to present a new technique which enables retrograde fillings to be achieved with gutta-percha and a sealer. After the apex had been resected, a hole was drilled perpendicular to the plane of section of the apex about 1 mm coronally. The bucco-lingual depth required to reach the main canal was calculated. The cavity was then dried, coated with the sealer, and obturated with gutta-percha in accordance with thermo-mechanical compaction techniques. After excess filling material had been removed, the gutta-percha was cold burnished and the angles of the root were smoothed. Clinical cases illustrating healing of the periapical tissues are shown.