Apexification with calcium hydroxide--when should the dressing be changed? The case for regular dressing changes

Pulp therapy and root canal treatment techniques in immature permanent teeth: an update

Background According to the Children's Dental Health Survey 2013, around one in ten children in Wales, Northern Ireland and England will have sustained dental trauma to a permanent incisor by the of age 15. Management of an exposed pulp in an immature permanent incisor is often urgent and has an impact on the long-term outcome of the tooth; therefore, it is essential that general dental practitioners feel confident in managing such a scenario to achieve an optimal outcome. This paper discusses the indications, technique, materials and outcomes.Aims This article aims to review the literature, which discusses various treatment modalities and materials for pulpal therapy and root canal treatment in the immature permanent tooth.Method Electronic searches were limited to English language, human studies, published within the past five years and the medical subject heading terms used were: direct pulp capping, apexogenesis, Cvek pulpotomy, full pulpotomy/pulpectomy, partial pulpotomy, apexification, non-vital pulp therapy and mineral trioxide aggregate apexification. Older, seminal articles identified through the references sections have also been included.Conclusion A number of options are available for the management of immature permanent teeth that have suffered an insult such as caries or trauma. This paper reviews the various methods of pulpal treatment, preservation therapy and root canal treatment options depending on the extent of the damage.

Regenerative Endodontic Therapy in the Management of Immature Necrotic Permanent Dentition: A Systematic Review

Materials and Methods

The electronic databases PubMed and Google Scholar were used to search the literature for relevant studies after applying specific inclusion and exclusion criteria. Studies that fulfilled both the inclusion and exclusion criteria were included in this systematic review. The search was conducted by two independent reviewers following the PRISMA guidelines.

Results

Only 46 studies that fulfilled both the inclusion and exclusion criteria, which were conducted within the last 10 years, were included in this systematic review. These studies investigated different aspects of regenerative endodontic therapy including different types of scaffolds, intracanal medications, pulpal space/barriers, root maturation stage, follow-up duration, and updated studies on their use in the management of immature necrotic permanent teeth.

Conclusions

This review concluded the compiled data observed that endodontic regenerative therapy was more efficient in treating immature necrotic permanent teeth and offered a greater advantage that should lead to wider acceptance among endodontists for effective results compared to different treatment options. However, more clinical trials with a standardized protocol and defined clinical, radiographic, and histopathological outcomes with longer follow-up periods are warranted.

Regenerative Endodontic Procedures Using Contemporary Endodontic Materials

Calcium hydroxide apexification and Mineral Trioxide Aggregate (MTA) apexification are classical treatments for necrotic immature permanent teeth. The first tend to fail for lack of compliance given the high number of sessions needed; the second has technical difficulties such as material manipulation and overfilling. With both techniques, the root development is interrupted leaving the tooth with a fragile root structure, a poor crown-to-root ratio, periodontal breakdown, and high risk of fracture, compromising long-term prognosis of the tooth. New scientific literature has described a procedure that allows complete root development of these specific teeth. This regenerative endodontic procedure (REP) proposes the use of a combination of antimicrobials and irrigants, no canal walls instrumentation, induced apical bleeding to form a blood clot and a tight seal into the root canal to promote healing. MTA is the most used material to perform this seal, but updated guidelines advise the use of other bioactive endodontic cements that incorporate calcium and silicate in their compositions. They share most of their characteristics with MTA but claim to have fewer drawbacks with regards to manipulation and aesthetics. The purpose of the present article is to review pertinent literature and to describe the clinical procedures protocol with its variations, and their clinical application.

Chlorhexidine Prevents Root Dentine Mineral Loss and Fracture Caused by Calcium Hydroxide over Time

Purpose. To evaluate the mineral ion loss of root dentine after treatment with 2% chlorhexidine solution (CHX) and to compare its yield and flexural strength (fs) after exposure to calcium hydroxide [Ca(OH)₂]. Materials and Methods. Dentine bars (DB) were made from 90 roots of bovine incisors and randomized into three groups: G_Control: distilled/deionized water (DDW), G_NaOCl: 2.5% sodium hypochlorite + 17% EDTA, and G_CHX: CHX + DDW. The release of phosphate (PO₄) and calcium (Ca) ions was measured by spectrophotometry. The DB were exposed to Ca(OH)₂ paste for 0, 30, 90, and 180 days. DB were subjected to the three-point bending test to obtain yield and fs values. The fracture patterns were evaluated (20x). Data were analyzed using Kruskal-Wallis and Dunn's post hoc tests or one- and two-way ANOVA followed by Tukey's post hoc test (α = 0.05). Results. G_CHX showed lower PO₄³⁻ and Ca²⁺ ionic release than G_NaOCl (p < 0.001). For yield and fs, G_CHX > G_NaOCl in all periods (p < 0.001), except for yield strength values on 90 days (p = 0.791). A larger frequency of vertical fractures was observed in G_NaOCl and that of oblique fractures in G_CHX (p < 0.05). Conclusions. CHX prevented PO₄³⁻ and Ca²⁺ loss and showed a tendency to preserve the yield and fs of root dentine over time following exposure to Ca(OH)₂ paste.

Use of platelet-rich plasma for regeneration in non-vital immature permanent teeth: Clinical and cone-beam computed tomography evaluation

Objective

This study was performed to assess the clinical and radiological outcomes of a revascularization procedure in immature teeth with apical periodontitis using platelet-rich plasma (PRP). The PRP protocol and conventional revascularization protocol, which used a blood clot as the scaffold, were compared.

Methods

Thirty non-vital immature permanent teeth were randomly categorized into two groups. After disinfecting the root canal space with triple antibiotic paste (1:1:1 ciprofloxacin, metronidazole, and cefaclor), a tissue scaffold was created using either PRP or a blood clot (control) and covered with white mineral trioxide aggregate. All cases were followed up clinically and radiographically for 12 months. Differences in bone density, root length, and lesion size were calculated using preoperative and postoperative computed tomography images. The means of the differences in individual parameters in the blood clot and PRP groups were compared using the Mann–Whitney U test.

Results

After 5 months, sensitivity tests (cold and electric pulp tests) elicited a delayed positive response in 23 sites. At 12 months, cone-beam computed tomography revealed resolution or a decrease in lesion size and an increase in bone density in all 30 (100%) teeth. Additionally, continued root development was observed in 22 (73%) teeth and early root growth was observed in the test group (mineral trioxide aggregate with PRP).

Conclusions

The results of this study suggest that PRP can serve as a successful scaffold for regenerative endodontic treatment. With the exception of a significant increase in root length, the results of treatment with PRP were not significantly different from those of the conventional protocol using a blood clot as the scaffold.

Management of incompletely developed teeth requiring root canal treatment

Endodontic management of the permanent immature tooth continues to be a challenge for both clinicians and researchers. Clinical concerns are primarily related to achieving adequate levels of disinfection as 'aggressive' instrumentation is contraindicated and hence there exists a much greater reliance on endodontic irrigants and medicaments. The open apex has also presented obturation difficulties, notably in controlling length. Long-term apexification procedures with calcium hydroxide have proven to be successful in retaining many of these immature infected teeth but due to their thin dentinal walls and perceived problems associated with long-term placement of calcium hydroxide, they have been found to be prone to cervical fracture and subsequent tooth loss. In recent years there has developed an increasing interest in the possibility of 'regenerating' pulp tissue in an infected immature tooth. It is apparent that although the philosophy and hope of 'regeneration' is commendable, recent histologic studies appear to suggest that the calcified material deposited on the canal wall is bone/cementum rather than dentine, hence the absence of pulp tissue with or without an odontoblast layer.

Pulp revascularization of immature maxillary first premolar

An immature maxillary first premolar in an 8-year-old female was treated using a regenerative approach. The root canal was gently irrigated with 5.25% sodium hypochlorite without instrumentation under aseptic conditions and then medicated with calcium hydroxide (Ca[OH]₂) for 3 weeks. The Ca(OH)₂ was removed, and bleeding was initiated mechanically using a hand file to form an intracanal blood clot. Mineral trioxide aggregate was placed over the blood clot, and the access cavity was sealed with a double filling. Increases in root length and width were radiographically evident, at the 6-month follow-up exam. The case was followed for 3 years. The development of 3 roots with complete apical closure was confirmed using cone beam computed tomography.

The effectiveness of pulp revascularization in root formation of necrotic immature permanent teeth: A systematic review

OBJECTIVE

The objective of the present study was to carry out a systematic review to analyse the effectiveness of pulp revascularization in the root formation of necrotic immature permanent teeth, as well as the level of scientific evidence regarding this theme.

MATERIALS AND METHODS

The methodology was based on searching electronic databases such as Web of Science, Pubmed, BVS (Medline, Scielo, Lilacs and BBO), Scopus and Cochrane, including manual searches for the references listed in the studies found. The terms used for the literature search were pulp revascularization and endodontics.

RESULTS

Initially, 277 articles were identified from the electronic databases; 17 studies remained after analysis and exclusion of duplicates; exclusion criteria also eliminated six articles; 11 remained for evaluation.

CONCLUSIONS

Although the results found in the present systematic review are relevant, the scientific evidence should be interpreted with caution as the articles report different methods and evaluation parameters. Despite the capacity of the pulp revascularization technique to stimulate the development of the apical closure and thickening of radicular dentin, several aspects still remain unknown, like the key factors of this repair, the type of tissue formed and the long-term prognosis.

Treatment options: apexogenesis and apexification

This article will describe requirements for case selection and review the procedures for apexogenesis and apexification in immature permanent teeth. Nonclinical and clinical data will be presented to support the recommendations, and outcomes will be presented from clinical studies. The dental pulp is an ectomesenchymally derived connective tissue with certain unique properties such as being encased in hard tissues, which limits its collateral circulation. The pulp provides a matrix for binding of its cells and provides support allowing communication between the cells. In addition to immune cells, the dental pulp contains odontoblasts, which are specialized cells capable of producing dentin. In the absence of a vital pulp, dentin deposition is arrested. When an immature tooth is affected by caries or trauma, the pulp requires proper management according to the degree of inflammation and its vitality. Maintenance of pulp vitality will allow continued root development along the entire root length. If the pulp is irreversibly inflamed or necrotic, root-end closure procedures are required when the apex has not fully formed.

Regenerative potential following revascularization of immature permanent teeth with necrotic pulps

AIM

To assess the regenerative potential of immature teeth with necrotic pulps following revascularization procedure in dogs.

METHODOLOGY

Necrotic pulps and periapical pathosis were created by infecting 108 immature teeth, with 216 root canals in nine mongrel dogs. Teeth were divided into three equal groups according to the evaluation period. Each group was further subdivided into six subgroups according to the treatment protocol including MTA apical plug, revascularization protocol, revascularization enhanced with injectable scaffold, MTA over empty canal. All root canals were disinfected with a triple antibiotic paste prior to revascularization with the exception of control subgroups. After disinfection, the root length, thickness and apical diameter were measured from radiographs. Histological evaluation was used to assess the inflammatory reaction, soft and hard tissue formation.

RESULTS

In the absence of revascularization, the length and thickness of the root canals did not change over time. The injectable scaffold and growth factor was no more effective than a revascularization procedure to promote tooth development following root canal revascularization. The tissues formed in the root canals resembled periodontal tissues.

CONCLUSION

The revascularization procedure allowed the continued development of roots in teeth with necrotic pulps.

Endodontic release system for apexification with calcium hydroxide microspheres

The use of calcium hydroxide (CH) as an intracanal medicament for apexification is widespread. However, because of a short residence time in the root canal, the CH must be refreshed frequently, increasing the number of appointments required and leading to patient non-compliance. We hypothesized that a core-/shell-structured CH microsphere system would lead to sustained slow release of calcium and hydroxide ions of CH for long periods of time, eliminating the need for multiple visits for apexification. In this study, calcium hydroxide microspheres (CHMSs) with a core/shell structure were prepared by an emulsion method. The CHMS shell was composed of alginate, which was crosslinked by the Ca(2+) released from the CH in the CHMSs. Therefore, this system provides a unique feedback loop that controls the release of ions from the CHMSs. The in vitro experiments from the root canals of extracted human teeth showed that the CHMSs had a sustained, slow release of Ca(2+), at a constant rate of approximately 2 to 3% per month from day one to the six-month endpoint of the experiment. After 6 months, 72.1 ± 5.8% of the total CH from the CHMSs remained in the root canals of the teeth, while only 46.9 ± 10.9% and 36.8 ± 7.5% remained from a commercial product (UltraCal(®)XS) and CH powder alone, respectively (p < 0.01). The pH of all of the formulations (CHMS, UltraCal(®) XS, and CH powder) in the extracted teeth never rose above 9 during the release period, indicating a buffering effect of the teeth. The core-/shell-structured CHMSs are, therefore, a promising delivery vehicle for the sustained slow release of Ca(2+) and OH(-) in the root canal.

Fracture resistance of human root dentin exposed to calcium hydroxide intervisit medication at various time periods: an in vitro study

The aim of this study was to evaluate the effect of calcium hydroxide on the fracture resistance of human root dentin at different time intervals. After root canal preparation, one hundred single-rooted premolar human teeth were randomly divided into two equal groups. After placement of calcium hydroxide paste within the canal, one group of teeth was divided into 5 subgroups and incubated for a period of 1 week or 1, 3, 6, or 12 months at 37°C and 100% humidity. The second group of teeth was also divided into 5 subgroups and incubated under the same conditions without placement of calcium hydroxide paste. After mounting the teeth in a Zwick test machine, the force required to break each tooth was determined. Data analysis was performed using the one- and two-way analysis of variance tests. The results demonstrated that the mean force needed to cause fracture differed significantly between the two groups during the first, third and sixth months of incubation (P = 0.001, P < 0.001 and P = 0.035, respectively), and the amount of force necessary for fracture was greater in the control group. Therefore, it would appear from this study that using calcium hydroxide as a long-term intracanal dressing showed a significant decrease in peak load at fracture when compared with the control groups at the end of the first, third and sixth months of treatment and would suggest that using Ca(OH)2 for periods longer than 1 month should be used with caution.

Complete Management of a Mutilated Young Permanent Central Incisor

This case report throws light on treatment of immature apices through apexogenesis and an esthetic postobturation restoration of traumatized young permanent central incisor using a relatively newer methodology of anatomic posts, i.e. shaping the post to the root anatomy. The authors would also like to underline the significance of rubber dam isolation for more predictable outcomes. The new method of anatomic post is simple, viable, practical, and less time consuming than thought.

Apexification: a review

This paper reviews the rationale and techniques for treatment of the non-vital immature tooth. The importance of careful case assessment and accurate pulpal diagnosis in the treatment of immature teeth with pulpal injury cannot be overemphasized. The treatment of choice for necrotic teeth is apexification, which is induction of apical closure to produce more favorable conditions for conventional root canal filling. The most commonly advocated medicament is calcium hydroxide, although recently considerable interest has been expressed in the use of mineral trioxide aggregate. Introduction of techniques for one-visit apexification provide an alternative treatment option in these cases. Success rates for calcium hydroxide apexification are high although risks such as reinfection and tooth fracture exist. Prospective clinical trials comparing this and one-visit apexification techniques are required.

The use and predictable placement of Mineral Trioxide Aggregate in one-visit apexification cases

Endodontic treatment of the pulpless tooth with an immature root apex poses a special challenge for the clinician. The main difficulty encountered is the lack of an apical stop against which to compact an interim dressing of calcium hydroxide (Ca(OH)2), or the final obturation material. In these situations the unpredictability of the result, the difficulty in creating a leak-proof temporary restoration for the duration of treatment, and the difficulty in protecting the thin root from fracture may lead to complications when using traditional (Ca(OH)2-based) apexification techniques. Furthermore, given the increased mobility of today's society, lengthy treatment protocols are fraught with problems, and may not be followed through to completion. This may lead to ultimate failure of the case. Mineral Trioxide Aggregate (MTA) has recently been introduced for use in endodontics. Current literature supports its efficacy in a multitude of procedures including apexification. The focus of this paper is to propose a one-visit apexification protocol with MTA as an alternative to the traditional treatment practices with Ca(OH)2. One-visit apexification may shorten the treatment time between the patient's first appointment and the final restoration. The importance of this approach lies in the expedient cleaning and shaping of the root canal system, followed by its apical seal with a material that favours regeneration. Furthermore, the potential for fractures of immature teeth with thin roots is reduced, as a bonded core can be placed immediately within the root canal.