BIOACTIVE ENDODONTICS

As dentists now thinking as “oral physicians,” we better understand that the future direction of endo­dontics is bioactive endodontics 

By definition, bioactive means having a biological effect. Bioactive endodontic treatment can be achieved via either vital pulp cryotherapy or regenerative endodontic 

Vital pulp cryotherapy integrates the use of sterile ice (cryotherapy) in conjunction with EDTA, bioceramics (BCs), and restorative materials on pulp tissue that has been exposed or indirectly exposed due to a carious lesion . 

Regenerative endodontics has been shown to provide a more biological approach to conventional endodontic treatment than the current clinical methodology. This procedure can be done on both vital and necrotic pulps of immature and mature permanent teeth. Regenerative endodontics uses periradicular blood to fill a prepared canal and thus eliminates the use of warm vertical and cold lateral compaction techniques, along with carrier-based root-fill   .  After completing a BC pulp cap or partial pulpectomy, a light-cured glass ionomer material or non-light-cured glass ionomer material should be placed directly over the BC pulp cap or partial pulpectomy. Next, a permanent restoration (composite or amalgam) is placed 

If the tooth cannot be permanently restored with a composite or amalgam, vital pulp cryotherapy is contraindicated, and the tooth should be treated with a full pulpectomy (regenerative endodontics.

REGENERATIVE ENDODONTICS

Regenerative endodontics is defined as biologically based procedures designed to physiologically replace damaged tooth structures, including dentin and root structures, as well as the pulp-dentin complex. This procedure is done when a full pulpectomy is indicated. It should be noted that in the endodontic literature, regenerative, revascularization, and revitalization endodontics are used synonymously and interchangeably.24 Reports in the literature have also demonstrated the use of regenerative endodontic procedures on not only immature permanent teeth with necrotic pulps but also on mature permanent teeth with necrotic pulps, teeth with persistent apical periodontitis after conventional endodontic treatment, traumatized teeth with external inflammatory resorption, teeth with horizontal fractures, and avulsed teeth.

 Regenerative endodontics has also been done on permanent, mature vital teeth (ie, pretreatment pulpal diagnoses of symptomatic irreversible pulpitis).

In regard to regenerative endodontic canal preparation, it is important to address residual canal debris. Since it is understood that rotary NiTi files stay centered in a canal, the field of endodontics has reported in the literature the use of various irrigation techniques and devices (ultrasonic, negative pressure, syringe, and photo-induced photo-acoustic streaming [PIPS]) to assist in chemomechanical canal preparations.

 Recently, the literature has reported on the use of the multi-sonic GentleWave system ، These studies have found that canals were significantly cleaner with the use of the GentleWave system compared to the various irrigation devices mentioned above.

There are some additional canal preparation guidelines that need to be followed when doing regenerative endodontics. First, the coronal two-thirds of the canal does not need to be overly enlarged. The reason for this is that the dentist does not have to be concerned with this portion of the canal being large enough to allow obturation instruments to gain access into the apical third of the canal. The coronal two-thirds of the canal’s conservative enlargement will also help to not weaken the tooth and thus prevent root fractures 2

Secondly, the final canal size of the apical foramen needs to be a minimum MAF size of 0.32 mm in order to allow the blood cells of the periapical tissue to migrate up into the canal space.

Thirdly, during the file canal preparation stage, the canal should be irrigated with 1.5% NaOCl (a lower concentration is used to reduce the killing of stem cells)16 and an EDTA gel (EndoGel [Jordco] or RC-Prep [Premier Dental]) should be placed on each file prior to canal placement.

Lastly, in teeth that have a pretreatment pulpal diagnosis of necrosis, it is recommended to treat these teeth in 2 visits. In these cases, after the canal preparation is completed, it is irrigated with 17% EDTA, dried, and temporized with the placement of Ca(OH)2 in the canal to serve as an antimicrobial medication between treatments.16 The canal access is temporized with a sterile cotton pellet or sponge and a temporary material (eg, Cavit Temporary Filling Material [3M], IRM Intermediate Restorative Material, or a glass-ionomer). The patient is then asked to return in 1 to 4 weeks for the final treatment appointment.

On the second appointment for a necrotic tooth, after the Ca(OH)2 medicament has been removed from the canal(s), or on the first appointment for a vital tooth, the canal(s) need to be flushed with 17% EDTA irrigation after canal preparating materials for canal obturation .

 The tissues generated in the canals after a regenerative endodontic procedure have been shown to be cementum-like, bone-like, and periodontal ligament-like tissues with blood vessels and nerves. Although these tissues are not true pulpal tissue, they are the host’s own vital tissue as opposed to foreign obturation materials (gutta-percha and sealer)

 vital PULP CRYOTHERAPY

There has been a paradigm shift in vital pulp therapy over the last 3 to 5 years. Prior to this time, vital pulp treatment has often been viewed as a temporary pulpal procedure, rather than a permanent one. When evaluating the “old school” technique for vital pulp therapy, it was done using NaOCl, Ca(OH)2, and a temporary filling material (eg, IRM Intermediate Restorative Material [Dentsply Sirona]). The use of these materials is the reason long-term prognosis following vital pulp therapy was poor. Also, we did not have a good understanding of the histological response of pulpal tissue to decay until Ricucci et al18 reported in the literature how the pretreatment pulpal diagnosis correlated to the clinical pulpal histology.

Vital pulp cryotherapy is a new technique that uses sterile ice, EDTA, BCs, and a permanent restoration (composite or amalgam). Vital pulp cryotherapy is done on teeth requiring a pulp cap or partial pulpectomy that can then be restored with an amalgam or composite restoration. Vital pulp cryotherapy is contraindicated when a tooth has a pretreatment periradicular diagnosis of asymptomatic apical periodontitis or chronic/acute apical abscesses or when the pretreatment pulpal diagnosis is necrotic. It is important to note that upon clinical access into a multi-rooted, “vital” tooth, if a clinician observes that the pulp is partially necrotic, it is also a contraindication for vital pulp cryotherapy treatment. Vital pulp cryotherapy is done under local anesthesia and using a rubber dam. If the pulp is exposed or indirectly exposed as a result of removing all the caries, as clinically demonstrated by the visual “blushing” of the pulp through a thin layer of dentin, vital pulp therapy is indicated. Shaved sterile-water ice (0° C) is then placed over a direct or indirect pulp exposure (Figure 3) for approximately 1 minute. No NaOCl should be applied to a direct pulp exposure when doing a vital pulp cryotherapy procedure. The reason for this is that NaOCl will kill the dental pulpal stem cells. EDTA solution should be used instead. EDTA has been shown to stimulate dental pulpal stem cells.21 After the melted sterile ice is suctioned away, 17% EDTA should be irrigated over the direct or indirect pulp exposure. It is not recommended to use an EDTA-soaked cotton pellet because the fibers from the cotton can remain after usage and be a source of inflammation of the pulp tissue. After EDTA irrigation, the direct or indirect exposed pulp is then covered with a BC material 4).

After completing a BC pulp cap or partial pulpectomy, a light-cured glass ionomer material or non-light-cured glass ionomer material should be placed directly over the BC pulp cap or partial pulpectomy.22 Next, a permanent restoration (composite or amalgam) is placed (Figure 5).

If the tooth cannot be permanently restored with a composite or amalgam, vital pulp cryotherapy is contraindicated, and the tooth should be treated with a full pulpectomy (regenerative endodontics).

REGENERATIVE ENDODONTICS

Regenerative endodontics is defined as biologically based procedures designed to physiologically replace damaged tooth structures, including dentin and root structures, as well as the pulp-dentin complex. This procedure is done when a full pulpectomy is indicated. It should be noted that in the endodontic literature, regenerative, revascularization, and revitalization endodontics are used synonymously and interchangeably. Reports in the literature have also demonstrated the use of regenerative endodontic procedures on not only immature permanent teeth with necrotic pulps but also on mature permanent teeth with necrotic pulps, teeth with persistent apical periodontitis after conventional endodontic treatment, traumatized teeth with external inflammatory resorption, teeth with horizontal fractures, and avulsed teeth. Regenerative endodontics has also been done on permanent, mature vital teeth (ie, pretreatment pulpal diagnoses of symptomatic irreversible pulpitis).

In regard to regenerative endodontic canal preparation, it is important to address residual canal debris.14 Since it is understood that rotary NiTi files stay centered in a canal, the field of endodontics has reported in the literature the use of various irrigation techniques and devices (ultrasonic, negative pressure, syringe, and photo-induced photo-acoustic streaming [PIPS]) to assist in chemomechanical canal preparations. Recently, the literature has reported on the use of the multi-sonic GentleWave system -these studies have found that canals were significantly cleaner with the use of the GentleWave system compared to the various irrigation devices mentioned above.

There are some additional canal preparation guidelines that need to be followed when doing regenerative endodontics. First, the coronal two-thirds of the canal does not need to be overly enlarged. The reason for this is that the dentist does not have to be concerned with this portion of the canal being large enough to allow obturation instruments to gain access into the apical third of the canal. The coronal two-thirds of the canal’s conservative enlargement will also help to not weaken the tooth and thus prevent root fractures.

Secondly, the final canal size of the apical foramen needs to be a minimum MAF size of 0.32 mm in order to allow the blood cells of the periapical tissue to migrate up into the canal space.16

Thirdly, during the file canal preparation stage, the canal should be irrigated with 1.5% NaOCl (a lower concentration is used to reduce the killing of stem cells)16 and an EDTA gel (EndoGel [Jordco] or RC-Prep [Premier Dental]) should be placed on each file prior to canal placement.

Lastly, in teeth that have a pretreatment pulpal diagnosis of necrosis, it is recommended to treat these teeth in 2 visits. In these cases, after the canal preparation is completed, it is irrigated with 17% EDTA, dried, and temporized with the placement of Ca(OH)2 in the canal to serve as an antimicrobial medication between treatments.16 The canal access is temporized with a sterile cotton pellet or sponge and a temporary material (eg, Cavit Temporary Filling Material [3M], IRM Intermediate Restorative Material, or a glass-ionomer). The patient is then asked to return in 1 to 4 weeks for the final treatment appointment 

On the second appointment for a necrotic tooth, after the Ca(OH)2 medicament has been removed from the canal(s), or on the first appointment for a vital tooth, the canal(s) need to be flushed with 17% EDTA irrigation after canal preparation