Tissue reactions induced Tissue reactions induced by dental pulp capping by dental pulp capping materials: a histological materials: a histological

studystudy

Ovidiu Cristea, Romeo Brezeanu, Ovidiu Cristea, Romeo Brezeanu,

Alexandra Stoica, Rania SesermanAlexandra Stoica, Rania Seserman((Lecturer Cosmin Moldovan,Assoc. Prof. Monica Lecturer Cosmin Moldovan,Assoc. Prof. Monica

Monea)Monea)

BackgroundBackground

Biocompatibility is a condition that must characterize all materials used in conservative dentistry, which means no risk of side effects on contact with host tissues.

In the case of pulp capping materials, this is expressed by many variables such as carcinogenesis, cytotoxicity, biocompatibility and antimicrobial effect.

Aim of the study Aim of the study

The purpose of our study is to evaluate the biocompatibility of materials used in pulp capping procedures, such as MTA and calcium hydroxide, by measuring the degree of inflammation induced by these products after subcutaneous implantation in experimental animals.

Material and methodMaterial and method

We used 12 animals divided in 3 study groups and 1 control group in which subcutaneous implants with MTA and calcium hydroxide containing products (Life, Calxyl)were placed; the histological evaluation was carried out after 7, 14 and 21 days. Our test was conducted according to international law (ISO/Tc 194)

Material and methodMaterial and method

Local anesthesia with 2ml Local anesthesia with 2ml Mebumal 10%, under rules of Mebumal 10%, under rules of asepsis and antisepsis;asepsis and antisepsis;

Postoperatively, the animals Postoperatively, the animals were not isolated and no were not isolated and no antibiotherapy was applied, antibiotherapy was applied, in order to avoid any effect in order to avoid any effect on tissue inflammatory on tissue inflammatory reactions. reactions.

Material and methodMaterial and method

Preparation of cotton Preparation of cotton implants containing dental implants containing dental materials on a sterile table. materials on a sterile table.

On a skin surface of 2 cm² a On a skin surface of 2 cm² a pocket was created, after a pocket was created, after a tissue incision of 1- 1,4 cm, tissue incision of 1- 1,4 cm, which was than elevated;which was than elevated;

The subcutaneous implant The subcutaneous implant was placed and sutured. was placed and sutured.

Histopathological evaluation Histopathological evaluation was carried out after 7, 14 was carried out after 7, 14 and 21 days.and 21 days.

Histopathological evaluationHistopathological evaluation

The histologic specimens were obtain according The histologic specimens were obtain according to a specific protocol; sections of 4 µm were to a specific protocol; sections of 4 µm were stained with Hematoxylin-Eosin and /or PAS and stained with Hematoxylin-Eosin and /or PAS and prepared for optical microscopic analisys. prepared for optical microscopic analisys.

The examination was carriede out by the same The examination was carriede out by the same person, who did not know the type of material or person, who did not know the type of material or moment of sample preservation.moment of sample preservation.

Criteria for histopathological Criteria for histopathological evaluationevaluation

0 = no inflammation: reaction zone similar to 0 = no inflammation: reaction zone similar to control, with none or only a few inflammatory control, with none or only a few inflammatory cells;cells;

1= mild inflammation: presence of plasma cells 1= mild inflammation: presence of plasma cells and macrophages;and macrophages;

2= moderate inflammation: inflammatory 2= moderate inflammation: inflammatory reaction with granulocites and limfocites beside reaction with granulocites and limfocites beside macrophages and plasma cells.macrophages and plasma cells.

3= severe inflammation: areas of necrosis, many 3= severe inflammation: areas of necrosis, many inflammatory cells in the surrounding tissue.inflammatory cells in the surrounding tissue.

Results Results Control group 7 daysControl group 7 days

Moderate Moderate inflammatory inflammatory infiltrate, infiltrate, multinucleated cells, multinucleated cells, enlarged blood enlarged blood vessels(vessels(HEHE stain 20X stain 20X).).

ResultsResultsMTA at 7 daysMTA at 7 days

Moderate reaction, Moderate reaction, with an important with an important inflammatory inflammatory infiltrate. The implant infiltrate. The implant placed in epithelial placed in epithelial tissue is surrounded tissue is surrounded by a limited necrotic by a limited necrotic zone (HE stain, 20X).zone (HE stain, 20X).

ResultsResultsCalxyd paste at 7 daysCalxyd paste at 7 days

Large necrotic Large necrotic zone, severe zone, severe inflammatory inflammatory infiltrate, infiltrate, numerous numerous hyperemic blood hyperemic blood vessels (HE stain, vessels (HE stain, 20X).20X).

ResultsResultsLife cement at 14 daysLife cement at 14 days

A connective tissue A connective tissue barrier is developing barrier is developing arround the implant;arround the implant;

The inflammatory The inflammatory reaction is reaction is moderate;moderate;

There are many There are many collagen fibres and collagen fibres and fibroblasts as signs fibroblasts as signs of tissue healing.of tissue healing.

Results Results MTA at 14 daysMTA at 14 days

Slight tendency of Slight tendency of tissue healing and tissue healing and reduced reduced inflammatory inflammatory infiltrate;infiltrate;

A connective tissue A connective tissue barrier is formed barrier is formed with the presence of with the presence of collagen fibres and collagen fibres and a few macrophages.a few macrophages.

ResultsResultsControl at 21 daysControl at 21 days

The implant placed The implant placed in subcutaneous in subcutaneous tissue shows tissue shows healing, with the healing, with the development of a development of a fibrous barrier. fibrous barrier.

Absence of Absence of inflammatory cells.inflammatory cells.

ResultsResultsMTA at 21 daysMTA at 21 days

Tendency to tissue Tendency to tissue healing and absence healing and absence of inflammatory of inflammatory infiltrate. infiltrate.

The implant was The implant was rarefied due to rarefied due to macrophages macrophages activity and a thin activity and a thin fibrous capsule had fibrous capsule had developed (PAS, developed (PAS, 20X).20X).

ResultsResultsCalxyde paste at 21 daysCalxyde paste at 21 days

The implant is The implant is surrounded by a surrounded by a fibrous capsule, fibrous capsule, there is no there is no inflammation and inflammation and the tissue is the tissue is considered healed. considered healed. (HE stain, 10X).(HE stain, 10X).

ResultsResultsLife cement at 21 daysLife cement at 21 days

A thick fibrous A thick fibrous barrier with a barrier with a septum surrounds septum surrounds the implant;the implant;

The adjacent tissue The adjacent tissue is considered is considered healed, free of healed, free of inflammation.inflammation.

(HE stain, 20X).(HE stain, 20X).

DiscussionDiscussion

Conservative treatment of the dental pulp is still Conservative treatment of the dental pulp is still a subject of intense debate, as there are many a subject of intense debate, as there are many methods that totally or partially preserve the methods that totally or partially preserve the vitality of this tissue. vitality of this tissue.

The most used material for capping procedures is The most used material for capping procedures is calcium hydroxide, due to its antibacterial and calcium hydroxide, due to its antibacterial and neodentinogenetic effects. Same effects were neodentinogenetic effects. Same effects were noted for MTA, which offers a tight seal and noted for MTA, which offers a tight seal and stimulated dentin bridge formation, with very stimulated dentin bridge formation, with very good results in direct pulp capping procedures.good results in direct pulp capping procedures.

DiscussionDiscussion

Our investigation was based on an experimental Our investigation was based on an experimental method widely used for in vivo studies, beeing method widely used for in vivo studies, beeing currently considered the most accurate approach currently considered the most accurate approach in evaluating the biocompatibility of dental in evaluating the biocompatibility of dental materials. materials.

Regarding the effect of surgical procedure upon Regarding the effect of surgical procedure upon experimental animals, we found no difficulty in experimental animals, we found no difficulty in the placement of subcutaneous implants, with no the placement of subcutaneous implants, with no interference with the general health of the study interference with the general health of the study groups.groups.

ConclusionsConclusions

The inflammatory reactions induces by MTA and The inflammatory reactions induces by MTA and Life cement are comparable, showing that there Life cement are comparable, showing that there are no major differences in the biocompatibility of are no major differences in the biocompatibility of these materials. these materials.

Anyway, this is not enough to rule out calcium Anyway, this is not enough to rule out calcium hydroxide containing materials from every day hydroxide containing materials from every day dental practice, due to its excellent results.dental practice, due to its excellent results.

Further clinical studies are necessary in order to Further clinical studies are necessary in order to evaluate the potential of MTA to induce dentin evaluate the potential of MTA to induce dentin bridge formation on exposed dental pulps and its bridge formation on exposed dental pulps and its long-term clinical outcome.long-term clinical outcome.

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