Sorin Andrian

REMINERALISATION OF AFFECTED DENTINE BY DIFFERENT BIOACTIVE MATERIALS IN STEPWISE EXCAVATION TECHNIQUE

Sorin Andrian1, Gianina Iovan2, Simona Stoleriu3, Claudiu Topoliceanu4, Andrei Georgescu5

1 Professor, Ph.D., Department of Odontology, Periodontology and Fixed Prosthodontics, Faculty of Dental Medicine, „Gr.T.Popa” University of Medicine anf Pharmacy, 16 Universitatii Str., 700115, Iaşi, Romania

2 Associated Professor, Ph.D., Department of Odontology, Periodontology and Fixed Prosthodontics, Faculty of Dental Medicine, „Gr.T.Popa” University of Medicine anf Pharmacy, 16 Universitatii Str., 700115, Iaşi, Romania

3 Lecturer, Ph.D., Department of Odontology, Periodontology and Fixed Prosthodontics, Faculty of Dental Medicine, „Gr.T.Popa” University of Medicine anf Pharmacy, 16 Universitatii Str., 700115, Iaşi, Romania

4 Assistant Professor Ph.D. student, Department of Odontology, Periodontology and Fixed Prosthodontics, Faculty of Dental Medicine, „Gr.T.Popa” University of Medicine and Pharmacy, 16 Universitatii Str., 700115, Iaşi, Romania

5 Assistant Professor Ph.D., Department of Odontology, Periodontology and Fixed Prosthodontics, Faculty of Dental Medicine, „Gr.T.Popa” University of Medicine and Pharmacy, 16 Universitatii Str., 700115, Iaşi, Romania

Rezumat

Scopul studiului a fost evaluarea capacităţii de remineralizare dentinară şi de menţinere a vitalităţii organului pulpo-dentinar în cazul utilizării unor materiale bioactive în cadrul tehnicii „stepwise”, după ce dentina infectată a fost îndepărtată cu ajutorul sistemului CarisolvTM (Sävedalen, Suedia).

Materiale şi metode. Studiul a fost realizat pe un număr de 25 pacienţi cu vârste cuprinse între 18 şi 34 de ani cu risc cariogen crescut la care terapia cariilor dentare a fost efectuată prin utilizarea tehnicii „stepwise”. În raport cu materialele utilizate au fost alcătuite trei loturi de dinţi: lot 1 (10 carii dentare cu evolutie acuta)- liner pe bază de hidroxid de calciu (Dycal, DeTreyDentsply) asociat cu ciment zinc-oxid eugenol (Caryosan, Spofa Dental); lot 2 (10 carii dentare cu evolutie acuta) – ciment zinc-oxid eugenol; lot 3 (10 carii dentare cu evolutie acuta)- liner pe bază de hidroxid de calciu în asociere cu ciment glassionomer (Ketac Molar Easymix, 3M ESPE). După un interval de 6 luni au fost evaluate modificările de culoare şi consistenţă la nivelul dentinei restante prin examen clinic şi radiografic, precum şi capacitatea de conservare a vitalităţii organului pulpo-dentinar.

Rezultate. În lotul 1, 100% din dinţi şi-au menţinut vitalitatea pulpară. În lotul 2 s-a înregistrat 1 caz de pulpită cronică cu reacţii subacute, asigurând un succes terapeutic de 90%. În lotul 3 a fost prezent 1 caz de necroză pulpară asociată cu reacţie periapicală cu un succes terapeutic de 90%.

Concluzii. Tehnica „stepwise” aplicată în cariile cu evoluţie acut progresivă la care îndepărtarea dentinei infectate s-a realizat utilizând sistemul CarisolvTM asigură remineralizarea dentinei restante într-un procent de 70-80% în funcţie de materialul utilizat şi conduce la menţinerea vitalităţii pulpare în procent de 90-100%.

Cuvinte cheie: carie acută, tehnica „stepwise”, CarisolvTM, remineralizare, dentină.

Abstract

Purpose. The aim of study was to assess the dentine remineralisation and the possibility to maintain the pulp vitality using several bioactive materials applied in „stepwise” excavation technique after the carious dentine was removed using the CarisolvTM system (Sävedalen, Sweden).

Materials and methods. The study was performed on 25 patients with high cariogenic risk, between 18-34 years old. 30 posterior teeth with acute dental caries were treated using „stepwise” excavation technique. The patients were divided in three study groups, according to the type of bioactive materials: group 1 (10 acute dental caries) – Ca(OH)2 liner (Dycal, DeTreyDentsply) and zinc-oxyde-eugenol (Caryosan, Spofa Dental); group 2 (10 acute dental caries) – zinc-oxyde-eugenol (Caryosan, Spofa Dental); group 3 (10 acute dental caries) – Ca(OH)2 liner (Dycal, DeTreyDentsply) and glassionomer cement (Ketac Molar Easymix, 3M ESPE). After 6 months the changes of colour and consistency of dentine were asessed using both clinical examination and radiographs, and the pulp vitality was tested.

Results. In study group 1, the dental vitality was maintained in 100% percent of the cases. In study group 2, a case of chronic pulpitis was recorded. In this study group, the dental vitality was maintained in 90% cases. In study group 3 a case of pulp necrosis associated with periapical lesion was recorded. This study group also presented therapeutical success in 90% cases.

Conclusions. „Stepwise” technique used after the removal of infected dentine with CarysolvTM system provided remineralisation of affected dentine in 70-80% percents and maintained the pulp vitality in 90%-100% cases.

Key words: acute dental caries, „stepwise” excavation technique, CarisolvTM, remineralisation, dentine.

            Introduction

The acute dental caries, characterised by deep demineralisation and high risk of pulp involvment, recquires a progressive therapeutical approach more adequate to mentain the pulp vitality. The therapy of acute dental caries, using the „stepwise” excavation technique, recquires the monitoring of pulp-dentine response to the materials applied for pulp capping. The traditional evaluation uses clinical examination, recording the changes of dentine colour and consistency during therapy. The neodentinogenesis and remineralisation reactions represent an important part of the pulp-dentin protection system, blocking the invasion of bacteria and their co-products.

There are two layers of altered dentine with different characteristics: the layer of infected dentine which is heavily contaminated and the layer of affected dentine, with lower degree of bacterial contamination. The infected dentine is soft and yellow and it is characterized by extensive breakdown of the organic matrix. This layer should be removed as its remineralisation potential is lost. The affected layer consists of dentine with medium consistency and some degree of elasticity. In many cases of acute dental caries it is difficult to clearly differentiate the limit between the two layers.  Since most of the recent data recommend the mantainance of the affected dentine, the „stepwise” excavation technique is focused on its preservation and remineralisation (1-7). For the asimptomatic cases where the pulp exposure seems possible during the treatment, the „stepwise” excavation technique is the most recommended therapeutical approach. The practical application of this technique presents considerable variations. The acceptable consistency of restant dentine can vary from soft to hard, while colour can vary from yellow to brown. There are also different opinions regarding the optimal moment for the removal of carious dentine.

The acute caries is characterised by periodes of intense activity of pulp tissue alternating with periodes of pulp inactivity. Despite the scientific data that highlight the possibility to preserve affected dentine in deep dental caries, most practitioners continues to apply basic surgical principles. Most practitioners are focused on the complete removal of carious dentine evan with the risk of pulp exposure (3). Also for the treatment of temporary teeth, most dentists perform pulpotomy instead of stepwise technique. However many researchers are focused to find efficient therapeutical procedures aimed to stimulate the defensive pulp-dentine complex processes (6,7). There are different recommendations regarding the bioactive materials used in „stepwise” excavation technique (calcium hydroxide-based products, zinc-oxyde-eugenol, glassionomer cements). The intervals between treatment stages can also vary, from 4 to 8 weeks or from 2 to 6 months (1-5).

During the last decades new methods have been developed for removal of carious dentine in an attempt to increase the efficacy, speed and patient comfort. In the absence of a clear macroscopic or microscopic delimitation between necrotic dentine and affected dentine (that can be remineralized), it was proposed to use the chemo-mechanical technique based on CarisolvTM system.

            The aim of study was to asses the capacity of some bioactive materials to stimulate dentine remineralisation and to preserv pulp tissue vitality, following the removal of carious dentine with the CarisolvTM system.

           

Methods

The study included 25 patients with age between 18-34, having 30 posterior teeth affected by acute dental caries and high caries risk. The presence of systemic diseases was an exclusion criteria. The patients were informed about the structure and objectives of study and informed consent was obtained. Ethics Commitee of „Gr.T.Popa” University of or Medicine anf Pharmacy gave its approval for this study.

The removal of carious dentine was performed with CarisolvTM system (Sävedalen, Sweden) by a single practitioner. The CarisolvTM gel was applied on carious dentine surface. The Carisolv gel was applied such as to cover the carious dentine from the lesion. After 30 seconds, the gel in the carious lesion was agitated using the excavators. The moist material was removed. A new layer of gel was applied and the procedure continued after waiting 30 seconds. The removal of the carious dentin was considered completed when the surface of the dentine felt as leather consistency.

The treatment was performed using the „stepwise excavation” approach. Depending on the bioactive materials, three study groups were formed: group 1 (10 acute dental caries) – calcium-hydroxide liner (Dycal, DeTreyDentsply) and zinc-oxyde-eugenol (Caryosan, Spofa Dental); group 2 (10 acute dental caries) zinc-oxyde-eugenol (Caryosan, Spofa Dental); group 3 (10 acute dental caries) – calcium-hydroxide liner (Dycal, DeTreyDentsply) and glassionomer cement (Ketac Molar  Easymix, 3M ESPE).

The assessment of the affected dentine was performed using two criteria: the colour (yellow, brown-yellow, dark-brown) and the consistency (soft, leather, hard) immediately after completing the excavation procedure and 6 months latter. The presence of dentine remineralisation was also assessed on the radiographic images. The vitality tests, assessing the vitality of pulp tissue, were performed using electric pulp test device (Digitest, Parkell Inc, USA). Statistical analyse of the results was performed using Mann Whitney test with a significance level p<0.05 two-tailed.

            Results

The results regarding the colour changes of the remineralised dentine (Leksell indices), after 6 months, highlighted changes for the study group 1 (Ca(OH)2+ zync-oxide-eugenol) as only in 20% cases the colour of the affected dentine remained yellow, while colour changed in 30% cases in yellow-brown, and in 50% cases in dark-brown. (Table 1). For the study group 2, the dentine colour was yellow in 30% cases, yellow-brown in 40% cases, and dark-brown in 30% cases (Table 1). For the study group 3, the dentine colour was yellow in 20% cases, yellow-brown in 50% cases, and dark-brown in 30% cases (Table 1).

No significant statistical differences were obtained when compared the colour changes of the remineralised dentine after 6 month in groups 1,2 and 3 (p>0.05) (table 2)

Table 3 presents the results regarding the consistency changes (Leksell indices) after 6 months. The study group 1 (Ca(OH)2 + zinc-oxyde-eugenol) recorded 50% cases with hard dentine (total remineralisation), 40% cases with leather consistency (partial remineralisation) and only 10% cases with soft dentine (absent remineralisation). The study group 2 (zinc-oxyde-eugenol) recorded 40% cases with hard dentine (total remineralisation), 40% cases with leather consistency (partial remineralisation) and  20% cases with soft dentine (absent remineralisation). The study group 3 (Ca(OH)2 + glassionomer cement) recorded 30% cases with hard dentine (total remineralisation), 50% cases with leather consistency (partial remineralisation) and 20% cases with soft dentine (absent remineralisation).

No significant statistical differences were obtained when compared consistency changes of the

The analyse of the radiographic images showed that in the study group 1 (Ca(OH)2 + zinc-oxyde-eugenol) the dentine remineralisation was present in 90% of the cases. In this study group, the remineralisation processes were absent in 10% cases. This was the lowest percent of failure from all the study groups. The study group 2 (zinc-oxyde-eugenol) recorded the presence of dentinal remineralisation in 80% cases. The study group 3 (Ca(OH)2 + glassionomer cement) recorded the presence of dentinal remineralisation in 80% cases. In Figure 1 is presented the radiographic aspect of demineralised dentine in deep acute carious lesion at 46 tooth. Figure 2 presents the radiographic aspect after 6 months of pulp capping with Ca(OH)2 and ZOE. It can be seen the area of dentinal remineralisation associated with neodentinogenesis and retraction of pulp beneath the mesial horn (Figure 2).

The pulp tissue vitality was preserved in 100% cases in the study group, 6 months after indirect pulp capping with Ca(OH)2 and zinc-oxyde-eugenol. For teeth undergoing pulp capping with zinc-oxyde-eugenol, one case of chronic pulpitis was recorded. This study group presented 90% therapeutical success, regarding the preservation of pulp tissue vitality. For teeth undergoing pulp capping with Ca(OH)2 and glassionomer cement, one case of pulp necrosis associated with chronic apical periodontitis was recorded. For this study group, the failure rate was 10%.

            Discussion

Preserving and remineralising affected dentine minimises the risk of pulp exposure during the treatment of acute caries. This approach usually requires materials which seal the cavity and medicate the dentine- pulp complex, allowing the preservation of the pulp vitality and apposition of tertiary dentin. These two aspects prove the importance of the temporary restorations in the treatment of acute dental caries.

Remineralisation is not a simple precipitation, but also a result of complex biochemical mechanisms initiated by the pulp tissue. The dentine remineralisation is also performed by the odontoblasts through the transfer of mineral salts from systemic circulation to the mineralisation area. In the cases where the remineralisation processes are stimulated by the glassionomer cements, the esential elements are represented by fluoride, calcium and strontium. Some glassionomer cements contain a high percent of calcium ions and low percent of strontium ions, while other contain high percent of strontium ions. The calcium ions have a major influence in the remineralisation of the affected dentine, while strontium ions have an important antibacterial effect and also stimulate the remineralisation processes. Fluoride ions and strontium ions can penetrate the demineralised dentine and become components of apatite cristals (8). For a short time, glassionomer cements also release aluminium ions that increase the enamel resistance to acidic attack.

Our results regarding the reactions of pulp-dentine complex, are similar with the results of several studies and support the widespread use of the „stepwise”. excavation technique. Some authors recommended the association between Ca(OH)2 liners and zinc-oxyde-eugenol for at least 3 months, with 80%-90% success rate, following the environment alcalinisation and odontoblasts stimulation by eugenol (1). The calcium ions released by Ca(OH)2-based liners influence both pasive and active remineralisation, by the activation of some enzymes associated to the remineralisation processes. Some studies have reported preservation of the pulp vitality in teeth with dentine remineralisation and neodentinogenesis, in 100% of cases, at an interval of 3-6 months (2). In this study, the researchers demonstrated that Ca(OH)2-based liners associated with zinc-oxyde-eugenol initiate neodentinogenesis and dentine remineralisation in 82,5% cases after 8-24 weeks. For the cases treated by indirect pulp capping with zinc-oxyde-eugenol, the authors reported 94% success rate after the removal of temporary restoration (1). Similar success rate was recorded in the „stepwise” excavation technique using the association of Ca(OH)2-based liners with zinc-oxyde-eugenol or glassionomer cements (9). Other studies reported 100% success rate after 6-12 months interval, following „stepwise” technique in acute dental caries (10). Results of some studies proved the association between dentinal remineralisation and massive decrease of bacterial concentration in carious dentine, after 6 months of „stepwise” therapy with zinc-oxyde-eugenol (11). Similar studies proved the dentine remineralisation following the penetration of dentinal tubules by fluoride and strontium ions (12,13).

Some authors sustain that the use of “stepwise” excavation technique in deep dental caries plays primary role in protecting the pulp-dentine complex (14). When using this technique, the practitioner can arrest the acute progression of the carious lesion, by modifing the cariogenic environment. The soft demineralised dentine is changing in most cases, into a dentine with increased consistency and brown-yellow or dark-brown appearance.

The efficiency of „stepwise” excavation technique was also assessed after 6-12 months by other authors (15). The clinical changes of demineralised dentine were associated with high reduction of bacterial contamination. After 6 months, in 90% cases the consistency of demineralised dentine increased, while in 20% cases there was a complete sterilisation of demineralised dentine. Using a standardised scale of consistency and colour changes, some authors found the remineralisation of dentine in 94% cases after 2-19 months following „stepwise” excavation technique (16). The clinical and radiographical changes of the demineralised dentine, following indirect pulp capping with Ca(OH)2 and zinc-oxyde-eugenol, after an interval of 6-7 months, were assessed by different authors (4). The affected dentine became hard dentine in 80% of the treated teeth, while 16,67% of teeth presented demineralised dentine with medium consistency. In the same study, only 3,3% cases were associated with total absence of remineralisation processes.

The „stepwise” excavation technique is included in the category of new operatory treatment options for the dental caries, but some authors claim potential failures in the long-term check-up of the treated teeth (17). Performing a critical review of 23 studies focused on this technique, the authors sustain the use of this technique on large scale for the treatment of deep acute dental caries. A similar critical review of such studies concluded that „stepwise” excavation technique present positive results on long-term, regarding the vitality preservation of pulp-dentine complex (18).

Conclusion

  1. The remineralisation of the affected dentine from acute carious lesions performed with zinc-oxide-eugenol or with calcium-hydroxide liner and glassionomer cement in „stepwise” excavation technique was present in 80% cases.
  2. After 6 months, 90% of the acute carious lesions treated with calcium-hydroxide liner and zinc-oxide-eugenol in „stepwise” excavation technique presented dentine remineralisation.
  3. The „stepwise” excavation technique is an efficient approach in the treatment of acute dental caries maintaining pulp vitality in 90-100% of the cases.

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