Introduction is dependent on its dissociation and the


















During clinical procedure, dental pulp is sometimes exposed. To
preserve the pup vitality, calcium hydroxide, which is considered the gold
standard, is used as a pulp capping material to stimulate the pulp to lay down
secondary dentin. As the world nowadays is shifting to natural products,
Propolis was introduced and has shown success more than the calcium hydroxide
in this field.

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As response to exposure, the pulp is involved in
a process called reparative dentinogenesis, where some of the cells deposit a
new matrix as a barrier in the injured site. It has been shown that adult
dental pulp contains precursor cells capable of forming odontoblast-like cells
in response to appropriate signals and materials. So, in certain cases, using
direct pulp capping to save pulpal health and function is recommended.

The ideal properties of pulp capping agents are
infection control, ease of handling, prevention of micro leakage and promotion
of hard tissue formation. During the reparative process, primary odontoblasts
that were lost are replaced with newly differentiated odontoblast-like cells.(Ahangari et
al., 012)(1)

Various materials have been used in vital pulp procedures,
especially direct pulp capping. Calcium hydroxide which is considered the gold
standard as pulp capping material   has been extensively and regularly used for
direct pulp capping in modern clinical dentistry as it is known to have a
potential role in inducing hard tissue repair.

This material has been applied to the exposed pulp and the
hard tissue is expected to be regenerated over the pulp, but recent studies
have confirmed that the antimicrobial effect of calcium hydroxide relates
directly to its high pH (12.5), which has destructive effect on cell membranes
and protein structures. The action of calcium hydroxide is dependent on its
dissociation and the release of hydroxyl ions (OH-), which diffuse into the
surrounding tissues and result in the formation of a necrotic layer and a zone
of coagulation necrosis with deposition of calcium and the absence of
odontoblasts which was misunderstood as reparative dentin. (Revathi e Natesan,
2014)(2), (Ahangari et
al., 2012) (1)

reparative dentin which is formed by calcium hydroxide is porous, non tubular,
contains tunnel defects and is not a complete barrier. Moreover, it causes
chronic and acute inflammation, hyperemia and micro leakage due to its high
solubility. (Ahangari et
al., 2012) (1)

Nowadays, the usage or incorporation of natural products is
highly demanded in dentistry. Therefore, Propolis which is a natural resinous
material, known for its bioactivity and antibacterial properties, was
investigated in few studies in order to induce dentin pulp complex. Hence
studying the effect of adding Propolis on the pulp capping material is highly
recommended and could be advantageous in dentistry.

















Search strategy

Data base and date of search:

The searching process was done through 2 databases: PubMed and
google scholar on the 5/10/2017

Index and mesh terms used:

Pulp capping, direct pulp capping, pulp capping materials, direct
pulp capping with Calcium Hydroxide, pulp capping in permanent teeth.

Propolis, Propolis in dentistry, green Propolis, Propolis in pulp

Results of search:

obtained results were 298 articles in PubMed and 136 in google scholar.
Filtration by “title and abstract” was done to get the eligible articles, which
resulted in 281 articles, then finally filtrated by “full text” to get the
included articles.


capping) OR (direct pulp capping) OR (pulp capping permanent teeth) OR (pulp
capping Calcium Hydroxide)) AND ((Propolis) OR (green Propolis) OR (Propolis
pulp capping) OR (Propolis oral health))


from 2000-2017





articles before 2000






Prisma flow chart



identified through google scholar
N= 136

identified through Pub Med
N= 298





Records after
duplicate removal
N= 425







Records excluded
N= 144

Records screened
N= 425


Studies included
 N= 20

Full text
articles excluded
N= 261

Full text
articles assessed for eligibility
N= 281





















Review of literature


Exposure of dental pulp during clinical procedure is very often. Therefore,
various materials have been used in direct pulp capping such as calcium
hydroxide (Ca(OH)2), ethanolic extract of Propolis, etc.…

Propolis (often referred as bee glue) is a resinous material
collected by bees from various plants that use it to seal the cracks in bee
hives Propolis is a mixture of resin, essential oil, waxes, minerals, vitamins
A, B complex, E, amino acids, and flavonoids. It has antimicrobial properties
that prevents microorganisms from entering the hives and causing illness. It
has antibacterial and antifungal activity specially against candida albicans.

In dental research, it has been found that it has an effect in
inhibiting certain enzymes responsible for dental caries and has a
desensitizing effect on sensitive teeth.

Revathi et al; 2014(2) calcium hydroxide which has been
used in dentistry for several decades as the main therapeutic agent due to having
many advantages, that’s why it has been used as the material of choice in vital
pulp therapy. But it was found that the barrier of osteodentine which is
produced, in incomplete and result in the formation of tunnel defects which in
turn allow bacterial reinfection. The 1.5-2 mm thickness necrotic layer may get
infected under leaking restoration causing pulpitis and subsequently pulp


Aeinehchi et al; 2003(3) compared the effect of MTA to
calcium hydroxide as pulp capping materials. They took 11 pairs of maxillary 3rd
molars and subjected them to mechanical pulp exposure. They were then capped
with MTA or calcium hydroxide, covered with ZnO/E and restored them with
amalgam. The teeth were then extracted after 1, 2, 3, 4 and 6 months. They
found that, MTA histological examination showed less inflammation, hyperemia,
necrosis, thicker dentin bridge and odontoblastic layer formation than Ca(OH)2.


Shaher et al; 2004(4) examined the tolerance of fibroblasts of the periodontal ligament
(PDL) and dental pulp to Propolis and compared them with that of calcium
hydroxide in vitro. Cells from human dental pulp and PDL were obtained from
healthy third molars and subjected to various concentrations of Propolis (0–20
mg/ml) and calcium hydroxide (0– 250 mg/ml). They analyzed cell viability after
Propolis treatment followed by spectrophotometric analysis. They found that,
exposure of PDL cells or pulp fibroblasts to 4 mg/ml or lower concentrations of
Propolis resulted in >75% viability of cells. On the other hand, calcium
hydroxide 0.4 mg/ml was cytotoxic and <25% of the cells were viable. They concluded that, further investigations may find Propolis to be a possible alternative for an intracanal antimicrobial agent. Sabir et al; 2005(5) assessed the response of rat dental pulp to direct pulp capping with Propolis. A class I cavity was prepared in maxillary 1st molar in rats. The pulp was exposed and capped with zinc oxide-base filler a control group (group 1), with Propolis flavonoids (group 2), or non-flavonoids (group 3). Biopsy were obtained and examined by light microscope. They found that, pulpal inflammation and absence of dentin bridge formation were evident in group 1 and 3 in contrast to group 2 where there was no inflammatory response and partial dentin bridge formation. They concluded that, direct pulp capping with propolis flavonoids in rats delayed dental pulp inflammation and stimulate reparative dentin formation.   Accorinti et al; 2008(6) evaluated the histomorphologic response of human dental pulps capped with mineral trioxide aggregate (MTA) and Ca(OH)2 cement (CH). Pulp exposures were performed on the occlusal floor of 40 human permanent premolars, then capped either with CH or MTA and restored with composite resin. After 30 and 60 days, teeth were extracted for histologic examination. They found that, all groups performed well in terms of hard tissue bridge formation, inflammatory response. However, a lower response of CH was observed for the dentin bridge formation when compared with MTA groups.  They concluded that, although pulp healing with calcium hydroxide was slower than that of MTA, both materials were successful for pulp capping in human teeth. Parolia et al; 2009(7) investigated the response of human pulp tissue which was mechanically exposed to a new material (Propolis) and compared it to two commercially existing and commonly used pulp capping agents (MTA and Dycal). Mechanical exposure of 36 intact human premolars. Teeth were divided into 6 groups of 6 teeth each and capped with Propolis, MTA and Dycal. Then resin composite was used as a final restoration using light cured glass ionomer cement as liner. The teeth were extracted on the 15th and 45th day for histological examination. Inflammatory response and dentin bridge formation were different with the 3 materials. They found that, more inflammation and less dentin bridge formation in teeth treated with Dycal than those treated with MTA and propolis. They concluded that, the response of pulp to propolis as a pulp capping material was comparable to MTA and Dycal.   Afonso etal; 2010(8) evaluated the biocompatibility of the new castor oil bean cement (COB) compared to the calcium hydroxide cement (CH) and a control group without any material in the sub-cutaneous tissues of rats. Animals were scarified at the 7th and 50th days after implantation. They found that, there was significant difference in number of inflammatory cells between the COB and CH while the was no significant difference between tissue reaction to CH and COB after 7 days whereas, after 50 days, significantly more inflammatory cells were observed in the CH group than in the COB group were observed. They concluded that, COB cement induces less inflammatory response within long periods.   Ahangari etal; 2012(1) evaluated the effect of propolis as a bioactive material on the quality of dentine and presence of dentine pulp stem cells. 48 incisors of guinea pigs were randomly divided into an experimental propolis group and control calcium hydroxide group. Pulp was capped using either propolis or calcium hydroxide and sectioning of the teeth was done to each group on the 10th ,15th and 30th day after they have been stained by hematoxylin and eosin (H). They found that, no significant difference between two groups in the presence of odontoblast-like cells, pulp vitality, congestion, inflammation of the pulp and the presence of remnants of used materials. Moreover, all of the propolis cases presented tubular dentine while 14% of the calcium hydroxide cases produced porous dentine. They concluded that, Propolis has advantages over calcium hydroxide as a capping agent in vital pulp therapy. In addition to, producing no pulpal inflammation, infection or necrosis this material induces the production of high quality tubular dentine.   Bedier M; 2016(9) assessed the cellular reaction of hamster kidney fibroblast cell line to mineral trioxide aggregate (MTA) and mineral trioxide aggregate mixed with propolis ethanolic extract (MTA-P). Extracts of the materials were prepared and collected in 24 h, 72 h and 7 days after mixing. Cells cultured in culture medium only without the extracts served as control. she found that, at 24 h, MTA-P showed higher cell number ratio than MTA (P < 0.05), At 72 h and 7 days, results showed no statistically significant difference among the groups.?She concluded that, early biocompatibility of MTA-P seems better than MTA, yet remains constant. MTA biocompatibility, however, seems to improve by time.   Gamal et al; 2017(10) evaluated the histological response of a healthy rabbit pulp to direct pulp capping with Propolis compared to Ca(OH)2. Twelve male rabbits were selected. Their dental pulps were intentionally exposed then the capping material was applied to both control and experimental group. Each group was subdivided into three subgroups, four rabbits for each, where rabbits were sacrificed after 1, 2 and 4 weeks from capping time respectively. Teeth were dissected and prepared for histopathologic and histochemical evaluation. They found that, 25%, 50% and 25% of dental pulps capped with calcium hydroxide showed mild, moderate and severe inflammatory response respectively, while in propolis group 75% and 25% showed slight to moderate inflammatory response respectively. Moreover, hard tissue formation in response to capping materials in calcium hydroxide group half of the cases showed moderate deposition and other half showed marked hard tissue deposited at fourth week. While in propolis group there was a marked deposition in 75% of cases and moderate deposition in 25% in the other. They Concluded that, Propolis proved to have less intense inflammatory response and better quality dentin bridge formation. In recent studies where Propolis was used as direct pulp capping material instead of Ca(OH)2, it was found that treatment with Propolis was associated with the formation of tubular dentin with no pores or connective tissue which was similar to primary dentin and the presence of odontoblasts which was referred to the ability of the Propolis to stimulate the production of transforming growth factor (TGF) Beta 1 which is important for the differentiation of odontoblasts. It also induces the synthesis of collagen by dental pulp stem cells. (Ahangari et al., 2012)(1) However, from the foregoing review, it was noticed that no studies were conducted to combine the best properties of Ca(OH)2 with that of Propolis and to improve the mode of application of Propolis.Therefore, this study will be conducted to evaluate the effect of adding Ethanolic Extract of Propolis to Ca(OH)2 as a pulp capping material. PICO   1.   Problem: Absence of reparative dentin following pulp capping with Ca(OH)2 2.   Intervention: Ca(OH)2 powder mixed with Ethanolic Extract of Propolis 3.    Control: Conventional Ca(OH)2 powder 4.   Outcomes: 1ry outcome Measuring device Dentin bridge formation Histological examination by light microscope   2ry outcome Measuring device Measuring unit Setting time Gilmore needle minute Solubility Digital balance Percentage %                                         Aim of the study The aim of this study will be to evaluate the effect of adding Ethanolic Extract of Propolis on commercially available Ca(OH)2 powder as regard dentin bridge formation, setting time and solubility.                                                           Research question Will pulp capping with Ca(OH)2 powder mixed with Ethanolic Extract of Propolis, induce reparative dentin formation in comparison to the conventionally used Ca(OH)2?                                                           Materials and methods   Materials 1.    Laboratory prepared Ethanolic Extract of Propolis (EEP) 2.    Commercially available chemically cured Calcium Hydroxide (Ca(OH)2) Methods        I.         Preparation of Ethanolic Extract of Propolis Propolis resin will be cut into small pieces and placed in Ethanol at room temperature. The mixture of Propolis resin and Ethanol will be placed in an automatic shaker inside an incubator for three days. After that it will be placed in a rotary evaporator that heats and evaporates the Ethanol under vacuum at 50°C until dryness. This process will remove the Ethanol, and any impurities will be separated leaving a precipitated dry mass of Propolis. The obtained dry mass will then be placed in a desiccator to prevent any moisture absorption till use. The dry extracted matter will be dissolved in Ethanol at room temperature and placed in an automatic shaker for 24 hours. It will then be filtered to obtain the Ethanolic extract of Propolis (EEP) that will be used to modify the Calcium Hydroxide (Ca(OH)2)    II.         Preparation of composites and grouping: EEP and distilled water will be used as a liquid for mixing the Ca(OH)2 powder forming pastes that will be divided into two main groups according to the treatment conducted: Group I:     Ca(OH)2 powder mixed with EEP and Distilled water Group II: Ca(OH)2 powder mixed with distilled water only (control Group) Characterization Chemical analysis of Ca(OH)2 powder and Ethanolic Extract of Propolis as well as between Ca(OH)2 and Ethanolic Extract of Propolis and between Ca(OH)2 and distilled water.           III.         Biological evaluation a.    Dentin bridge formation Rabbits' teeth will be used in the current study. Class v labial cavities will be prepared in rabbits' anterior teeth. Pulp exposure of approximately 0.5mm to 1mm diameter under saline spray solution without plugging the bur into the pulp. The material will then be applied to the pulp without pressure and cavity will be restored. After 25±5 days the rabbits will then be sacrificed and the teeth will be removed together with surrounding soft and hard tissue and fixed in a suitable fixing agent. The sections will then be examined under microscope for histopathology. Full description of the extent, nature and distribution of any dentin bridge, will be recorded and graded in a scale of none, partial or complete. Presence or absence of tunnel defects and cellular inflammation which may interfere with effectiveness of the bridge as a barrier will also be detected.(11)   Inflammation will be graded in a scale of  0: No Inflammation 1: Mild Inflammation 2: Moderate Inflammation 3: Severe Inflammation 4:Abscess formation (11)   IV.         Setting time Specimens discs will be prepared in a split Teflon having an internal diameter of 10mm and thickness of 2mm on a glass plate. Different cements pastes will be placed into the mold and after 150 ± 10 sec Gillmore needle will be lowered onto the horizontal surface of the pastes and checked for indentation. This will be repeated till failure of indentation. (12)     Solubility Solubility test will be conducted according to ADA no 61 for Zinc polycarboxylate cement. Specimens will be prepared using a split Teflon mold of 20 mm in diameter and 1.5 ± 0.3 mm of thickness. For each specimen a clean weighing bottle will be used. An additional blank bottle without specimen will also be used for determination of the residue present in the distilled water. The bottles will be dried in the oven, then cooled at room temperature in a desiccator containing silica gel; and then weighed. After setting of the specimens, they will be placed in their corresponding bottles and weighed. The prepared discs will be suspended by a floss and submerged in distilled water. Distilled water will be poured into the blank bottle and stored in the same incubator containing the specimens. Then, specimens will be removed and the water will be evaporated. The empty bottles will be dried for 24 hours and cooled then weighed. The increase in mass of the blank bottle due to presence of distilled water residue will be determined. The difference between the final weight of the weighing bottle and its initial weight was determined to calculate the amount of disintegration. (13) Specimen residue  % disintegration =                                                     x 100 (13) initial mass of the specimen                                      References   1.     Ahangari Z, Naseri M, Jalili M, Mansouri Y, Mashhadiabbas F, Torkaman A. Effect of propolis on dentin regeneration and the potential role of dental pulp stem cell in guinea pigs. Cell J. 2011;12(4):223–8. 2.     Revathi N, Sharath Chandra SM. Merits and Demerits of Calcium Hydroxide as a Therapeutic Agent: A Review. Int J Dent Sci Res. 2014;2(6B):1–4. 3.     Aeinehchi M, Eslami B, Ghanbariha M, Saffar AS. Mineral trioxide aggregate (MTA) and calcium hydroxide as pulp-capping agents in human teeth: a preliminary report. Int Endod J. 2003;36(3):225–31. 4.     Al-Shaher A, Wallace J, Agarwal S, Bretz W, Baugh D. Effect of propolis on human fibroblasts from the pulp and periodontal ligament. J Endod. 2004;30(5):359–61. 5.     Sabir A, Tabbu CR, Agustiono P, Sosroseno W. Histological analysis of rat dental pulp tissue capped with propolis. J Oral Sci. 2005;47(3):135–8. 6.     de Rezende GP da SR, da Costa LR de RS, Pimenta FC, Baroni DA. In vitro antimicrobial activity of endodontic pastes with propolis extracts and calcium hydroxide: A preliminary study. Braz Dent J. 2008;19(4):301–5. 7.     Parolia A, Kundabala M, Rao NN, Acharya SR, Agrawal P, Mohan M, et al. A comparative histological analysis of human pulp following direct pulp capping with Propolis, mineral trioxide aggregate and Dycal. Aust Dent J. 2010;55(1):59–64. 8.     Camargo SEA, Rode S de M, do Prado RF, Carvalho YR, Camargo CHR. Subcutaneous tissue reaction to castor oil bean and calcium hydroxide in rats. J Appl Oral Sci. 2010;18(3):273–8. 9.     Bedier M. Effect of mineral trioxide aggregate with or without propolis extract on the proliferation of fibroblast cell line. Tanta Dent J. 2016;13(4):208. 10.    Gamal A, Khattab N, Fouda T, Tohamy. S. Histological Evaluation of Response To Direct Pulp Capping With Propolis: Experimental Study in Rabbit. Int J Adv Res. 2017;5(2):2325–33. 11.    ISO 7405. Dentistry – Evaluation of biocompatibility of medical devices used in dentistry. 2013;(December). 12.    ADA Specification No 57 Endodontic Sealing Materials. 1983; (December) 13.  American National Standard Institute/ American Dental Association specification no.61 for zinc polycarboxylate cement, JADA, 101, 1980.                                               .


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