Theracal vs Vitrebond, how to use Dycal

Current recommendations for maintaining the vitality of the pulp

Scientific communication from the German Society for Endodontology and Dental Traumatology

The complete loss of function of the pulp tissue in the context of a root canal treatment is associated with a higher susceptibility to caries, tooth discoloration and the risk of fractures. Therefore, one should use the opportunities to maintain vitality. The German Society for Endodontology and Dental Traumatology sheds light on the current state of knowledge on vital-preserving measures of the pulp and gives recommendations for clinical procedures based on this.

1.1. Definition and goals of vital maintenance measures

In recent years, the issue of maintaining vitality has increasingly become a topic of awareness among the dental profession. When excavating a deep caries, attention should be paid to the remaining dentine layer over the pulp. While it has been taught for many years to excavate caries down to the healthy and probe-hard dentin (cri dentinaire), it is now accepted to leave dentin that is selectively infected near the pulp in order to avoid exposure of the pulp tissue [Buchalla et al., 2017] . The classic measures to maintain vitality, direct capping and pulpotomy, are also discussed. The standardized division into reversible and irreversible pulpitis with the associated therapeutic decision on vitality maintenance or vital extirpation is currently being questioned, and an expansion of the indication towards pulpotomy is becoming apparent.

The collective term "vitality-preserving measures" summarizes conservative treatment measures that serve to protect exposed dentin and pulp areas from further external stimuli by applying a capping material and placing a bacteria-proof restoration and to allow microorganisms (and / or components of filling materials) to penetrate prevent. On the one hand, the status of the pulp at the time of the intervention is decisive, and on the other hand, the extent of the lesion or the degree of infection of the dentin. The vital-preserving measures include the supply of dentin near the pulp (caries profunda treatment or indirect capping), direct capping, and pulpotomy or vital amputation.

The aim of all vital-preserving measures is to create a situation with previously damaged pulp that enables the formation of a hard tissue barrier and healing of the tissue, keeps it functional and thus ensures that a vital tooth remains in the oral cavity in the long term.

  • Vital-preserving measures should protect exposed dentin and pulp areas from further stimuli after the application of a capping material and a bacteria-proof restoration, and the penetration of microorganisms should be prevented.

1.2. Function and loss of function of the pulp tissue

The essential functions of the tooth pulp include the formation of dentin during tooth development and over the entire service life of the tooth, the transmission of stimuli via proprio and pain receptors, the immune function against invading bacteria and their metabolic products, the formation of irritant or repair dentin as a defense mechanism against external stimuli and in the special case of young teeth, the formation of root pulp and dentine and thus the completion of root growth.

Contrasted with vitality-preserving measures is root canal treatment, in which the pulp tissue that is still present is removed as completely as possible, the canal system is expanded and disinfected and finally obturated using root canal filling materials. Although success rates of over 90 percent can be achieved after about five years with a careful procedure after vital extirpation [Friedman et al., 2003], this always results in a complete loss of function of the pulp tissue, which is certainly associated with disadvantages. Thus, the proprioceptive protective mechanism is partially lost. It has been described that a root canal treated tooth allows a 2.5 times higher load than a vital tooth before a proprioceptive reaction takes place [Randow et al., 1986]. A resulting higher risk of fractures has not been proven, but is conceivable. In addition, changes in the root canal geometry (weakening of the root canal wall dentine due to preparation), which are unavoidable in the course of root canal treatment, can lead to a higher incidence of fractures [Fuss et al., 2001; Lertchirakarn et al., 2003]. Other possible problems that can arise in the context of root canal treatment are tooth discoloration [Krastl et al., 2013] and an increased susceptibility to caries, due to increased plaque accumulation and changed microflora [Merdad et al., 2011] or due to the lack of defensive capabilities of the pulp -Dentin complex and the lack of a pain warning system. Root canal treatment can also turn out to be more complex than initially assumed. Methods for maintaining the vitality of the pulp are conservative and comparatively easy to implement and inexpensive measures [Hørsted-Bindslev et al., 2003; Schwendicke et al., 2014].

The penetration of microorganisms and their metabolic products creates a stimulus that leads to the development of an inflammatory reaction in the pulp. The immune response is initiated via cell receptors on odontoblasts, dendritic cells and pulp fibroblasts. This initially leads to hyperemia, the resulting inflammatory reaction is characterized by a decrease in the number of cells, a flattening of the odontoblasts and the immigration of lymphocytes and plasma cells [Ricucci et al., 2014b]. Clinically, this correlates initially with the development of reversible pulpitis, in which it is assumed that healing of the tissue can be made possible by the therapeutic intervention. If the stimulus persists, bacteria can be detected in the pulp cavity, microabscesses and tissue necrosis appear, which are fringed by polymorphonuclear neutrophilic granulocytes, and inflammatory infiltrates can be found in the periphery [Ricucci et al., 2014b]. This stage is called irreversible pulpitis.

A positive sensitivity test and stimulus-related pain speak in favor of reversible pulpitis. Irreversible pulpitis is diagnosed with (intensely) positive sensitivity test, with radiating, stimulus-persisting pain or constant pain, pain on warmth and possibly inadequate localization of the pain-causing tooth on the part of the patient. However, irreversible pulpitids can also be asymptomatic [American Association of Endodontists, 2015]. Vital measures are only indicated if the clinical diagnosis of reversible pulpitis is made. According to current doctrine, in the case of irreversible pulpitis, healing of the tissue after removal of the triggering stimulus cannot be predictably achieved, which is why the diagnosis of "irreversible pulpitis" requires the initiation of root canal treatment. Although there are indications that the histological observations described above correlate well with the clinical diagnosis [Ricucci et al., 2014b], it should be mentioned here that the clinical classification of the symptoms says little about the regenerative capacity of the tissue. It only makes the treatment decision easier for the practitioner, as he can proceed schematically. The diagnosis and therapy scheme for the condition of the pulp and the derivable therapy are increasingly being called into question. Therefore, the indication for pulpotomy in irreversible pulpitis is currently in flux and is being investigated in clinical studies.

Vitality-preserving measures can only be successful if an infection of the pulp can be ruled out during and after the therapy. According to the current state of knowledge, vital maintenance measures should only be carried out on teeth that do not show any pronounced pain symptoms (reversible pulpitis). Vital measures should or cannot be carried out if there is no reaction to the sensitivity test (the pulp status must be verified after opening the pulp cavity), sensitivity to knocking or bite, spontaneous or persistent pain, as well as radiological signs of periapical osteolysis. Furthermore, exclusion criteria after opening the cavum are heavy bleeding that cannot be stopped or the discharge of serous or putrid exudate as well as necrotic tissue that is no longer supplied with blood. Teeth for which a bacteria-proof seal cannot be guaranteed due to limited restorability should be excluded. In order to rule out an infection of the exposed pulp tissue during or after the capping, further requirements must be met, including the use of sterile instruments, the placement of a rubber dam, the complete excavation of the caries and the possibility of immediate and permanent bacteria-proof closure. If these prerequisites are not all met with certainty, root canal treatment (or extraction) should be given preference.

Favorable conditions for maintaining vitality are given in a young pulp without previous damage [Wang et al., 2017]. With increasing age, a reduced regenerative capacity due to pulp changes in the sense of a pulp with fewer cells and more fibers is to be expected [Goodis et al., 2012; Murray et al., 2002]. Nevertheless, the patient's age only seems to play a subordinate role in terms of the success of treatment [Asgary et al., 2015; Cvek, 1978; Cvek et al., 1983; de Blanco, 1996; Fuks et al., 1982; Kang et al., 2017; Kunert et al., 2015; Linsuwanont et al., 2017; Mente et al., 2010; Taha et al., 2017]. The same applies to factors such as tooth position and the size or position of the pulp exposure [Dammaschke et al., 2010].

In general, it should be noted that the success rates of vital maintenance measures given in the literature vary greatly, especially in the case of direct capping after caries excavation. Early clinical failures (within days or weeks) are multifactorial, but certainly correlate with improper diagnosis of pulp status. This can result in underestimating the inflammatory status of the pulp, which can lead to the development of irreversible pulpitis and pulp necrosis, which can lead to postoperative pain.

  • The indication for vital maintenance is currently only given after the diagnosis of “reversible pulpitis”. The clinical classification of the symptoms, however, says little about the regenerative capacity of the tissue. Factors such as patient age, tooth position and size or position of the pulp exposure seem to play a subordinate role with regard to the success of the treatment.

In German usage, indirect capping refers to the medical supply of a thin layer of caries-free dentine that has remained close to the pulp [Schäfer et al., 2000]. Clinically, this situation usually arises when excavating a deep caries, so that the indirect capping is also called deep caries treatment. In the English-language literature, the term “indirect pulp capping” is defined somewhat differently, namely as the permanent capping of a thin, cariously altered dentin layer near the pulp without the caries being completely excavated in a second session [Babbush, 2008; European Society of Endodontology, 2006]. Because only a minimal dentin layer remains over the vital pulp tissue, there is a risk of irreversible inflammation of the pulp via the dentin tubules: on the one hand due to microorganisms that have remained or have already penetrated the tissue, on the other hand due to cytotoxic components from the filling materials that are caused by the thin residual dentine can diffuse. The dentin near the pulp should be disinfected and sealed against bacteria using a capping material, and the pulp should be stimulated to form tertiary dentin [Ricucci et al., 2014a]. This form of tertiary dentine is also known as reaction or irritation dentine. By definition, reactive dentin is formed by surviving postmitotic primary odontoblasts [Smith, 2012]. The indirect capping thus serves to protect the vital pulp, especially after caries removal. If reversible pulpitis already exists in advance, the indirect capping should create the conditions for pulp healing. Despite understandable reasons that speak in favor of a separate treatment of the dentin near the pulp in the sense of direct capping, it should not be left unmentioned at this point that there is currently no evidence for this measure from clinical studies [Buchalla et al., 2017].

If possible, indirect capping should also be carried out with controlled drainage with a rubber dam. To avoid the spread of germs, it is advisable to disinfect the clinical crown with sodium hypochlorite (NaOCl; 1–5 percent) or chlorhexidine digluconate (CHX; 2 percent) before excavation.

Microorganisms and thus every carious process that spreads in the direction of the pulp pose a risk to the pulp [Ricucci et al., 2013]. Therefore, the number of microorganisms in the cavity and in the vicinity of the pulp should be reduced as far as possible during caries excavation. The question of how much changed dentine can be left in order to allow the pulp to heal has not yet been clearly clarified [Buchalla et al., 2017].

After the excavation has been completed, the cavity must be cleaned with NaOCl or CHX and water spray [Bogen et al., 2008; Cao et al., 2016]. There is no need to fear damage to the vital pulp tissue when NaOCl is used [Rosenfeld et al., 1978]. Materials for indirect capping should possibly kill microorganisms remaining close to the pulp, neutralize the acidic tissue caused by the carious defect, remineralize dentin and stimulate the pulp to form tertiary dentin [Maeglin, 1955]. Calcium hydroxide has traditionally been recommended for this since the 1930s [Hermann, 1928]. Due to the disadvantages of aqueous calcium hydroxide suspensions, the use of hydraulic calcium silicate cements is nowadays possibly the better alternative even for indirect capping [Akhlaghi et al., 2015]. A definitive adhesive filling should be made in the same session for each type of capping material. Irritant dentin can form after indirect capping, but depending on the degree of damage to the odontoblasts, repair and deposition of an atubular mineral structure is more likely. Irritation and repair dentin can also be found next to each other histologically [Ricucci et al., 2014a].

  • The capping material disinfects with indirect capping, stimulates the formation of tertiary dentine and protects the pulp from toxic components of a subsequently applied dentine adhesive.

Direct capping is defined as covering the exposed pulp. The cause can be tooth decay, preparatory measures or traumatic exposure. The indication is given when diagnosing "reversible pulpitis".

After clinical and, if necessary, radiological findings, the tooth is isolated with a rubber dam and the clinical crown is disinfected. Care must be taken to use sterile instruments. Complete caries excavation is carried out with slowly rotating round burs and hand instruments from peripheral to central, ideally using optical magnifying aids (magnifying glasses, microscope). A cotton pellet soaked in NaOCl is recommended for hemostasis and disinfection. A calcium hydroxide suspension or a hydraulic calcium silicate cement is then applied to the opened pulp and the surrounding dentine, leaving a sufficiently wide dentine border free for the adhesive restoration. In order to avoid unintentional removal of the capping material when closing the cavity, we recommend covering it with a hardening preparation. The dentin should then be thoroughly sprayed with water to minimize the negative effects of the disinfectant solution on the adhesive bond. The definitive adhesive closure should be done in the same session. Since the exposure of the pulp goes hand in hand with the destruction of the local odontoblasts, the hard tissue formation induced by the capping is a repair process in which an amorphous mineralization tissue usually formed by fibroblasts is created [Ricucci et al., 2014a].

  • With direct capping, the capping material is applied to the exposed pulp. It is advisable to use magnifying aids, sterile instruments, and sodium hypochlorite to stop bleeding.

 

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The pulpotomy (pulp amputation) is a therapeutic method for maintaining the vitality of the pulp after artificial opening of the crown pulp (iatrogenic, traumatic). The pulp of the crown is partially amputated (partial pulpotomy) or up to the root canal entrance (complete or cervical pulpotomy) and, after successful hemostasis, is supplied analogous to the procedure for direct capping [American Association of Endodontists, 2015; Krastl et al., 2014].

5.1.Partial pulpotomy

In partial pulpotomy, the crown pulp is reduced by about 2 mm starting from the exposed area in order to remove potentially inflamed and irreversibly damaged pulp parts and to keep the remaining pulp vital [Bimstein et al., 2016]. Partial pulpotomy is preferably performed with a small dissection diamond [Granath et al., 1971]. The coronal 2 mm of the pulp is removed at high speed, ideally with continuous irrigation with physiological saline solution [European Society of Endodontology, 2006]. For reasons of practicality, however, pulp amputation is often carried out under water cooling with a contra-angle handpiece [Fong et al., 2002]. It has not been proven whether the use of correctly prepared contra-angle handpieces can be expected to have disadvantages in terms of less certainty of success.

As with direct capping, rinsing the amputation site with NaOCl is recommended for partial pulpotomy until the bleeding stops. If the formation of a blood clot is prevented, the same repair mechanisms of the pulp can be expected as with direct capping [Cohenca et al., 2013; Cvek et al., 1983]. If the remaining pulp is healthy, the bleeding can be expected to stop within five minutes. If the hemostasis does not succeed within this time, this is taken as an indication that the pulp has not been reduced to a healthy level. In this case, a complete pulpotomy, i.e. the removal of the entire crown pulp, can be considered as the last possible vital-preserving measure [Krastl et al., 2014].

A calcium hydroxide suspension or a hydraulic calcium silicate cement is applied to the artificially exposed pulp surface and a thin layer of a hardening material is applied locally [Cohenca et al., 2013]. Since larger amounts of the capping material are used in partial pulpotomy than in direct capping, the risk of tooth discoloration would also have to be classified as higher when using hydraulic calcium silicate cements [Krastl et al., 2014]. The bacteria-proof restoration follows.

5.2. Complete pulpotomy

In the complete pulpotomy, the entire crown pulp is removed and the root pulp to be preserved is then capped at the level of the canal entrances. The rest of the procedure is analogous to the partial pulpotomy. This is followed by a bacteria-proof final restoration [Krastl et al., 2014].

  • In the partial pulpotomy, around 2 mm of the pulp tissue is removed using a diamond grinder and water cooling; in the complete pulpotomy, the pulp is removed up to the entrance of the root canal. The bleeding should stop within 5 minutes after flushing with sodium hypochlorite. The application of the capping material is carried out in the same way as direct capping.

6. Overcap materials

6.1. Preparations containing calcium hydroxide

Calcium hydroxide is still widely used as a capping material today. In aqueous suspension it has a high pH value, it has a bactericidal effect, can neutralize bacterial acids and lipopolysaccharides in dentin and also leads to the release of growth factors bound in dentin [Graham et al., 2006]. Calcium hydroxide thus supports the formation of hard tissue and the healing of the pulp [Duque et al., 2006; Smith et al., 1995]. Disadvantages are the mechanical instability and the resorption of the material over time [Barnes et al., 1979; Goracci et al., 1996]. After calcium hydroxide application, porosities (“tunnel defects”) are observed in the repair dentine, which can serve as entry ports for microorganisms [Cox et al., 1996a]. The high pH value of aqueous calcium hydroxide suspensions leads to liquidation necrosis in direct tissue contact [Staehle, 1990]. Calcium hydroxide should only be applied over a small area in the area of ​​the pulp exposure or in the area of ​​the cavity near the pulp [Barnes et al., 1979; Staehle, 1990; Staehle, 1998]. Calcium hydroxide in aqueous suspension is preferred over other calcium hydroxide combinations (calcium salicylate ester cements, liners or putties). These show a significantly lower release of hydroxyl ions [Staehle et al., 1988], continuous disintegration under the main filling [Barnes et al., 1979], they induce slower and less dense hard tissue formation [Phaneuf et al., 1968 ] and some additives that cause the material to harden may have a pulp toxic effect [Liard-Dumtschin et al., 1984].

Newer, light-curing liners and cements with calcium hydroxide or MTA additives (product examples: Ultrablend Plus, Ultradent, South Jordan, USA; Calcimol LC, VOCO, Cuxhaven or TheraCal LC, Bisco, Schaumburg, USA) should also be viewed critically. The products lack the specific, bioactivity-triggering calcium hydroxide effect [Camilleri et al., 2014; Subramaniam et al., 2006]. A cytotoxicity of these products, which can be attributed to the monomer content, has been clearly demonstrated [Hebling et al., 2009]. According to current data, capping the pulp with light-polymerizable calcium hydroxide or calcium silicate-containing materials is not advisable.

6.2. Dentine adhesives and composites

In the meantime, the use of dentine adhesives as capping materials has been propagated [Cox et al., 1998; Cox et al. 1987; Cox et al., 1996b], following the idea that the bacteria-proof seal is crucial for the success of vital maintenance measures [Akhlaghi et al., 2015; Schuurs et al., 2000]. However, due to the monomers they contain, dentine adhesives have a toxic effect [Costa et al., 2000; Dammaschke et al., 2010b], which largely remains near the pulp due to the incomplete polymerization caused by moisture [Modena et al., 2009]. Components of dentin adhesives have also been shown to have a mineralization-inhibiting effect on pulp cells [Galler et al., 2011]. Dentine adhesives and composites are fundamentally not biocompatible [Costa et al., 2000] and should therefore be rejected as capping material [Akhlaghi et al., 2015].

6.3. Calcium silicate based hydraulic cements

With the introduction of hydraulic calcium silicate cements such as Mineral Trioxide Aggregate (MTA), aqueous calcium hydroxide is no longer regarded as the first choice for maintaining the vitality of the pulp [Akhlaghi et al., 2015; Cao et al., 2016]. In terms of materials, hydraulic calcium silicate cements are similar to Portland cements known from the construction industry. They are called "hydraulic" because they harden and are resistant both in the air and under water [Berzins, 2014]. Calcium silicate cements mainly consist of di- and tricalcium silicate and are mixed with water. During the reaction and the subsequent hardening, calcium hydroxide is released over a longer period of time [Berzins, 2014], which explains the persistent antibacterial properties [Parirokh, 2010]. Hydraulic calcium silicate cements are biocompatible and promote the formation of hard tissue in pulp cells [Zanini et al., 2012]. Mineral components from the cement interact with the dentin [Atmeh et al., 2012], resulting in dentin adhesion similar to that of glass ionomer cements [Kaup et al., 2015]. The advantage compared to calcium hydroxide products lies in the higher mechanical strength, the lower solubility and the more tight seal [Dammaschke et al., 2014]. Even if more clinical long-term studies on the maintenance of vitality of the pulp with hydraulic calcium silicate cements would be desirable, based on the current data, these seem to be more suitable than calcium hydroxide for capping the pulp [Akhlaghi et al., 2015; Hilton et al., 2013; Kundzina et al., 2017; Mente et al., 2014].

Hydraulic calcium silicate cements can lead to discoloration of the hard tooth substance, which can be particularly problematic in the case of anterior teeth, for example after trauma [Mozynska et al., 2017]. The causes are the heavy metals contained, such as bismuth oxide as an X-ray contrast medium [Berger et al., 2014; Dettwiler et al. 2016] or iron [Shokouhinejad et al., 2016]. The oxidation of these metals after contact with sodium hypochlorite or the absorption of blood components play a role here [Camilleri, 2014; Lenherr et al., 2012; Shokouhinejad et al., 2016]. With hydraulic calcium silicate cements that contain less or hardly any heavy metals, the possible tooth discoloration is less. Calcium silicate cements that contain zirconium oxide or tantalum oxide as X-ray contrast media appear particularly color-stable. Lipski et al. (2018) 18 months after direct capping with such a cement, no gray discoloration of the teeth was found in any case. In the presence of blood, however, discoloration was also detected for these materials in vitro [Shokouhinejad et al., 2016]. In the case of vital-preserving measures after pulp exposure, contact of these capping materials with blood is unavoidable, but from an aesthetic point of view, their use does not seem to be problematic, at least in the posterior region [Mozynska et al., 2017].

  • According to current data, hydraulic calcium silicate cements appear to be more suitable than calcium hydroxide for capping the pulp exposed during caries excavation.

 

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7. Preservation of vitality after trauma-related pulp exposure

In most cases, exposure of the pulp after dental trauma offers an ideal prerequisite for vital maintenance measures, provided that these are carried out correctly and there is no previous damage to the pulp. To simulate the conditions after dental trauma, crown fractures with pulp exposure were induced in an older animal study on monkeys. The pulps, which were in direct contact with the oral cavity for three hours, two and seven days, were then examined histologically. Depending on the duration of exposure, inflammatory pulp changes were found, which, however, remained limited to the coronal 2 mm even after up to seven days [Cvek et al., 1982]. The results were confirmed by Heide and Mjör in 1983 and suggest that partial pulpotomy with removal of 2 mm pulp tissue in the coronal area can still be successful after several days in contact with the oral cavity [Heide et al., 1983]. It must be taken into account that if the fractured tooth is dislocated, the blood flow and thus the resistance of the pulp can be compromised [Robertson et al., 2000].

  • The traumatic pulp exposure usually offers ideal conditions for healing after vital maintenance measures.

8. Preservation of vitality after caries-related pulp exposure

Compared to teeth with traumatic damage, after exposure to caries, there is always prior damage to the pulp due to the more or less long-term contact with bacterial toxins or even the bacteria themselves. The size of the lesion, the spectrum of germs and the speed at which the lesion progresses all have an effect on the pulp status. When supplying dentin close to the pulp in the sense of indirect capping, the transitions to direct capping are fluid. Even with a remaining dentin layer, the pulp is affected by incision of odontoblastic processes in the dentin near the pulp. The pulp tissue can also be exposed at points without this being clinically noticed, which is why careful inspection of the cavity with magnifying glasses is recommended.

Since microorganisms can remain even after complete caries excavation and careful disinfection, it is advisable to apply the capping material not only in the area of ​​the opening, but also on the surrounding dentin in order to effectively combat these bacteria. This increases the success rate of pulp capping, especially in teeth with deep caries [Bogen et al., 2008]. For calcium hydroxide, however, it must be noted that large-area application can lead to disintegration and mechanical instability [Barnes et al., 1979; Goracci et al., 1996]. Furthermore, after opening the pulp in the carious dentin, contamination of the tissue with infected dentin chips is likely. If it is foreseeable that the pulp will open, the use of a new, sterile round bur near the pulp is recommended. Since pulp tissue capping is only indicated after the caries has been completely excavated, pulpotomy can be considered if the caries is exposed in the carious dentin after excavation. In this way, infected dentine chips that have already been transported into the pulp and damaged tissue can be removed, thus improving the prerequisites for healing.

  • In the case of carious teeth, the pulp is previously damaged by bacteria and their toxins. Direct lapping should only be performed if the excavation is complete at the time of opening. If the opening is made in the carious dentine, further excavation is necessary, after which a pulpotomy can be considered.

9. Follow-up exams and success rates

The failure of vital maintenance measures is caused by an infection, which can be traced back to either remaining microorganisms or the penetration of new bacteria along a gap between the tooth and the filling material in defective restorations [Ørstavik et al., 2007]. This can also lead to pulp necrosis and the development of periapical inflammatory processes without being noticed. Therefore, the sensitivity should be tested regularly after vital maintenance measures, first after 3, 6 and 12 months, then annually. A thermal sensitivity test with cold spray or CO2 snow is suitable. The limited reaction after partial and especially after cervical pulpotomy is to be expected and should not be regarded as a criterion for failure. A radiological check is only recommended in the event of a negative sensitivity test [Klimm, 2003]. It should be noted here that a possible new formation of hard substance in the area of ​​the opening or the amputation point cannot be clearly assessed. Even a slight widening of the periodontal gap does not have to be of any pathological significance [Ahrens et al., 1973].

A clinical treatment success after vital maintenance measures of the pulp is present if the teeth are classified as "clinically normal", that is, if they react to the sensitivity test, no spontaneous pain, pain on palpation or percussion and no swelling can be observed. Radiographically, no changes, such as periapical lesions, should be visible. If a tooth does not react to the sensitivity test or if it is painful to percussion and / or palpation, or if the x-ray shows periradicular radiolucency, then the treatment can be assumed to have failed. Teeth on which root canal treatment is indicated after capping or which have to be extracted are also a clinical failure [Duda et al., 2009].

The available studies suggest that after partial pulpotomy there is no higher risk of obliteration of the root canal [Barrieshi-Nusair et al., 2006; Kang et al., 2017; Mass et al., 2011; Qudeimat et al., 2007]. In comparison, a full pulpotomy increases the risk of obliteration in the long term. While the risk is classified as very low in the first two years [Asgary et al., 2016; Galani et al., 2017; Simon et al., 2013], partial obliterations occur in 30 percent of the cases after a mean observation period of three years [Linsuwanont et al., 2017] and in almost 40 percent of the cases after a mean observation period of 4.8 years.

Vitality-preserving measures after trauma offer a high degree of success, provided that the pulp is not previously damaged or the blood flow is compromised by an accompanying dislocation injury. For direct capping with calcium hydroxide, the prognosis is given as 54 to 90 percent [Fuks et al., 1982; Hecova et al., 2010; Ravn, 1982]. The partial pulpotomy with the same material has a higher certainty of success with 86 to 100 percent [Alqaderi et al., 2016; Cvek, 1978; Cvek, 1993; Cvek et al., 1983; de Blanco, 1996; Hecova et al., 2010; Wang et al., 2017] and should therefore be favored. It remains to be seen whether the high degree of success achieved with calcium hydroxide suspension in partial pulpotomy after traumatic pulp exposure can be increased by a clinically relevant amount when using hydraulic calcium silicate cements [Krastl et al., 2014].

Although the conditions for maintaining vitality after pulp exposure in the context of caries excavation appear less favorable than after traumatic exposure, good success rates are nonetheless possible. With indirect capping when using calcium hydroxide preparations, these are between 62 and 98 percent after three to ten years [Akhlaghi et al., 2015; Ingle et al., 1985]. With regard to hydraulic calcium silicate cements and indirect capping, there are currently hardly any studies in the literature, so that further investigations in this regard appear necessary [Parirokh et al., 2018].Clinically and radiologically, teeth after indirect capping with MTA showed higher success rates after three months than after using a hardening calcium salicylate ester cement (Dycal, Dentsply Sirona, Konstanz). After six months, however, this result was put into perspective [Leye Benoist et al., 2012].

The success rates quoted in the literature for direct capping after pulp exposure in the context of caries excavation vary greatly [Barthel et al., 2000; Hilton et al., 2013; Mente et al., 2014]. Provided that the indication is correct and the technical implementation is correct, direct capping with calcium hydroxide can achieve success rates of almost 60 percent after ten years [Mente et al., 2014; Willershausen et al., 2011]. After using hydraulic calcium silicate cements such as Mineral Trioxide Aggregate (MTA), however, these are about 80 percent higher [Hilton et al., 2013; Kundzina et al., 2017; Lipski et al., 2018; Mente et al., 2014].

For partial pulpotomy after caries excavation using hydraulic calcium silicate cements, the success rates after two years are 85 to 97 percent [Chailertvanitkul et al., 2014; Ozgur et al., 2017; Taha et al., 2017] and after four years it was almost 94 percent [Mass et al., 2011].

For a full pulpotomy using hydraulic calcium silicate cements, the success rates after one to five years are 74 to 100 percent [Asgary et al., 2013; Asgary et al., 2015; Asgary et al., 2018; Galani et al., 2017; Linsuwanont et al., 2017; Nosrat et al., 2013; Qudeimat et al., 2017; Simon et al., 2013; Taha et al., 2017]. Particularly noteworthy is that in the studies mentioned on complete pulpotomy, teeth with the diagnosis of irreversible pulpitis were also included. Should further studies confirm these initial data over longer periods of time, the indication for vital maintenance measures could in future be extended to teeth with already irreversibly damaged pulp areas (diagnosis of irreversible pulpitis), and in the course of a partial or complete pulpotomy these areas could be specifically removed in order to preserve vitality the remaining pulp.

Despite overall favorable data for vital endodontic measures after pulp exposure as part of caries excavation, selective or two-stage caries excavation is another treatment alternative that may have comparable successes. Compared to the vital maintenance measures mentioned above after pulp exposure in the course of caries excavation, the 5-year success rates for selective caries excavation are 80 percent and for gradual caries excavation 56 percent [Maltz et al., 2018]. A clinically relevant difference with regard to the probability of success of a pulp capping or pulpotomy compared to selective and also step-by-step caries excavation can therefore not be determined.

For a direct comparison of the two treatment strategies, there is currently only one clinical study, the 1- and 5-year data of which have been published [Bjørndal et al., 2017; Bjørndal et al., 2010]. In this study, the prognosis of the two-stage excavation was compared with the prognosis after complete excavation with subsequent direct capping or partial pulpotomy. While after two-stage caries excavation it was possible to preserve the vitality of the pulp after five years in 60 percent of the cases, the prognosis after direct capping of 6 percent and after partial pulpotomy with 11 percent in the same period was far below the success rates of vital preservation measures in the other studies. The most likely cause discussed is that in this clinical study, after capping or partial pulpotomy, the cavity was only provided with a temporary closure for the first 8 to 10 weeks instead of an immediate permanent restoration [Bjørndal et al., 2017]. Furthermore, the lack of disinfection after opening the pulp and the choice of capping material (Dycal) are to be regarded as problematic. These factors may have contributed to the low success rates in this study. The data do not coincide with the information in the rest of the literature, which, if correctly indicated and carried out, certify vital-preserving measures a favorable prognosis.

  • Clinical and, if necessary, radiological follow-up checks should be carried out regularly after vital maintenance measures.

10. Final evaluation

The improved understanding of the interaction between microorganisms and tissue response has led to the increased use of minimally invasive, tissue-friendly treatment concepts in tooth preservation in recent years. In this sense, vitality-sustaining measures can keep the body's own pulp tissue functional and avoid its replacement by a synthetic material. In the case of a given indication, the maintenance of the pulp's vitality should always be sought. According to the current state of knowledge, the assessment of vital maintenance measures as unsafe treatment measures is outdated. Assuming careful diagnosis and adequate implementation of all necessary treatment steps, the prognosis of vitality-preserving measures can be assessed as very good, which can improve the prerequisites for long-term tooth preservation.

A higher probability of success of the currently propagated selective or step-by-step caries excavation compared to the vital-preserving measures after exposure of the pulp cannot be ascertained. It is the task of future, well-planned clinical studies to find out which procedure creates better conditions for the maintenance of the pulp's vitality in the long term. In the future, it will also be necessary to evaluate whether a long-term preservation of vitality through the targeted removal of irreversibly damaged areas is also possible when diagnosing “irreversible pulpitis” using a partial or complete pulpotomy.

  • Preservation of the pulp's vitality should always be aimed for when the indication is given. A higher probability of success of the selective caries excavation compared to the vital maintenance measures after exposure of the pulp cannot be determined. It is the task of future, well-planned clinical studies to find out which procedure creates better conditions for the maintenance of the pulp's vitality in the long term.
    Studies meanwhile show the successful use of pulpotomy in the diagnosis of "irreversible pulpitis"; the concept of vital maintenance measures is therefore in flux and an expansion of the indication is conceivable.

Prof. Dr. med. dent. Till Dammaschke
Polyclinic for Periodontology and Dental Conservation, Münster University Hospital
Albert Schweitzer Campus 1, Building W 30
48149 Munster
[email protected]

Prof. Dr. med. dent. Kerstin Galler, Ph. D.
Polyclinic for Dental Preservation and Periodontology, University Hospital Regensburg
Franz-Josef-Strauss-Allee 11
93053 Regensburg
[email protected]

Prof. Dr. med. dent. Gabriel Krastl
Polyclinic for Dental Preservation and Periodontology, University Hospital Würzburg
Pleicherwall 2
97070 Wuerzburg
[email protected]

The scientific report of the German Society for Endodontology and Dental Traumatology e.V. (DGET) was published for the first time in: Deutsche Zahnärztliche Zeitschrift | 2019; 74 (1)

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