Direct Pulp Capping Material Research Articles

Cytotoxicity and biocompatibility of resin-free and resin-modified direct pulp capping materials: A state-of-the-art review.

Direct pulp capping is the placement of a dental material directly over exposed pulp to prevent dental pulp from dying and avoid the need for root canal treatments. Calcium hydroxide and calcium silicates/mineral trioxide aggregates (MTA) have been commonly used for direct pulp capping with great success clinically. In recent years, resin-modified calcium hydroxide and calcium silicates have been developed with the advantages of precise placement, command set, and superior physical strength. As pulp capping materials would be in direct contact with the pulp, the cytotoxicity and biocompatibility is of particular importance in order to avoid pulp irritation and maintain pulp vitality. Therefore, this review article will summarize the cytotoxicity and biocompatibility of direct pulp capping materials, particularly resin-modified materials.

Pulp Response following Direct Pulp Capping with Dentin Adhesives and Mineral Trioxide Aggregate; An Animal Study.

Introduction:Pulp vitality and its continuous dentin prodution are essential for long-term success of direct pulp capping (DPC). The aim of present study was to evaluate the histopathological response of the canine pulp following DPC using either different dentin adhesive resins (DAR), calcium hydroxide (CH) or mineral trioxide aggregate (MTA). Methods and Materials:DPC was done on 72 dog’s teeth using 6 types of dental materials (n=12) (4 types of DAR, white MTA and CH). Therefore, six healthy dogs were anesthetized and 2 teeth from each dog were allocated to either type of mentioned DPC agents. The dental pulps were exposed mechanically by drilling in the center of class V cavities. The different types of capping materials included DARS (Clearfil S3 Bond, Optibond FL, Single Bond and Clearfil SE Bond), white MTA and CH. After 7, 21 and 63 days, two dogs were euthanized in each interval. Microscopic evaluations were done according to following criteria: intensity of inflammation, presence of necrosis and formation of hard tissue. The recorded data were analyzed by the Kruskal-Wallis, Friedman, Cochran’s and Fisher’s exact tests using SPSS software version 12 at significant level of 0.05. Results:No significant differences were found regarding necrosis among DPC materials (P>0.05). However, MTA caused higher amount of hard tissue formation after 63 days in comparison with 21 days. Conclusion:MTA provided the highest degree of hard tissue formation after 63 days. However, further studies should be performed for administering a definitive material.

The thickness of odontoblast-like cell layer after induced by propolis extract and calcium hydroxide

Background: Propolis is a substance made from resin collected by bees (Apis mellifera) from variety of plants, mixed with its saliva and various enzymes to build a nest. Propolis has potential antimicrobial and antiinflammatory agents with some advantages over calcium hydroxide (Ca(OH)2). Ca(OH)2 has been considered as the “gold standard” of direct pulp-capping materials, but there are still some weakness of its application. First, it can induce pulp inflammation which last up to 3 months. Second, the tissue response to Ca(OH)2 is not always predictable. Third, the tunnel defect can probably formed in dentinal bridge with possible bacterial invasion in that gap. Purpose: This study was aimed to determine and compare the thickness of odontoblast-like cells layer after induced by propolis extract and Ca(OH)2 in rat’s pulp tissue. Method: Class 1 preparation was done in maxillary first molar tooth of wistar mice until the pulp opened. The Ca(OH)2 and propolis extract was applied to induce the formation of odontoblast-like cells, the cavity was filled with RMGIC. The teeth were extracted (after 14 and 28 days of induction). The samples were then processed for histological evaluation. Result: There were significant differences between the thickness of odontoblast-like cells after induced by propolis extract and Ca(OH)2. Conclusion: The propolis extract as the direct pulp capping agent produces thicker odontoblast-like cell layer compared to Ca(OH)2.

Effects of Bioactive Compounds on Odontogenic Differentiation and Mineralization

Direct pulp capping involves the placement of dental materials directly onto vital pulp tissues after deep caries removal to stimulate the regeneration of reparative dentin. This physical barrier will serve as a “biological seal” between these materials and the pulp tissue. Although numerous direct pulp capping materials are available, the use of small bioactive compounds that can potently stimulate and expedite reparative dentin formation is still underexplored. Here, the authors compared and evaluated the pro-osteogenic and pro-odontogenic effects of 4 small bioactive compounds— phenamil (Phen), purmorphamine (Pur), genistein (Gen), and metformin (Met). The authors found that these compounds at noncytotoxic concentrations induced differentiation and mineralization of preosteoblastic MC3T3-E1 cells and preodontoblastic dental pulp stem cells (DPSCs) in a dose-dependent manner. Among them, Phen consistently and potently induced differentiation and mineralization in vitro. A single treatment with Phen was sufficient to enhance the mineralization potential of DPSCs in vitro. More importantly, Phen-treated DPSCs showed enhanced odontogenic differentiation and mineralization in vivo. Our study suggests that these small bioactive compounds merit further study for their potential clinical use as pulp capping materials.

Nestin expressions of exposed pulp after direct pulp capping by calcium hydroxide and platelet rich plasma.

Objective:The aim of this study was to evaluate nestin expression of pulp tissue following direct pulp capping with platelet-rich plasma (PRP).Materials and Methods:The thirty sound teeth from Sprague-Dawley rats were used and divided into two groups: Groups 1, teeth were capped with calcium hydroxide/Ca(OH)2 (n = 15) and Group 2 with PRP (n = 15). After 1st, 7th, and 21st days, respectively, 5 teeth each group (American Dental Association 41) were processed for light microscopic examination. Expressions of nestin were assessed by immunohistochemical techniques.Results:Nestin expression of Ca(OH)2 on the distance place of exposure at 1st and 7th days were 80% and at 21st day were 60%. Nestin expression of PRP on the distance place at 1st day was 80%, 7th 100%, and 21st day was 80%. At day 21 observation, Kruskal–Wallis test shows nestin expression was increased significantly in PRP groups (P < 0.05), but it was not increase significantly compare with Ca(OH)2.Conclusion:PRP had ability as a direct pulp capping material to induce nestin expression.

Prognostic factors in direct pulp capping with mineral trioxide aggregate or calcium hydroxide: 2- to 6-year follow-up.

The aim of this retrospective study was to evaluate the influence of various predictors on healing outcomes after direct pulp capping (DPC) using either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) as a pulp-dressing agent. The present study included 172 mature asymptomatic permanent teeth with carious-exposed pulp. The teeth were treated with DPC, using either MTA or CH, and the treatment outcome was evaluated clinically and radiographically. The effect of potential clinical variables on the treatment outcome of DPC was evaluated clinically and radiographically during a 24-72-month follow-up. In order to assess the cumulative successes of CH and MTA after DPC, Kaplan-Meier survival analysis and log-rank test was used. The subgroups were compared by means of the log-rank test. Also, univariate Cox regression analysis was used to determine hazard ratio of clinical variables. One hundred and fifty-two teeth of 172 capped teeth were available for follow-up, with an overall recall rate of 87.6% for MTA vs 89.3% for CH. The mean period of follow-up was 37.3 (±17.2) months. Overall success rates of 85.9 and 77.6% in the MTA and CH groups were observed, respectively. The cumulative success rate of both materials was not statistically different when analysed by the Cox proportional hazard regression analysis (P=0.282). The Kaplan-Meier survival curves revealed that 2-year overall pulp survival was 91.4%, while the 4- and 6-year survival rates were 84 and 65%, respectively. None of the clinical variables had a considerable influence on the outcome of DPC (p>0.05). MTA-capped teeth demonstrated a slightly higher success rate than CH, revealing that it can be recommended as a reliable direct pulp-capping material. None of the clinical variables investigated significantly affected posttreatment healing. DPC with MTA is a straightforward procedure with favourable outcome of 24- to 72-month follow-ups in vital mature asymptomatic permanent teeth with cariously exposed pulp, and it may be considered a realistic alternative therapy to RCT.

Different materials for direct pulp capping: systematic review and meta-analysis and trial sequential analysis.

We systematically assessed randomized controlled trials comparing direct pulp capping materials. Trials comparing materials for direct capping and evaluating clinically and/or radiographically determined success after minimum 3months were included. Two reviewers independently screened electronic databases (Medline, Central, Embase) and performed hand searches. Risk of bias was assessed and meta-analyses were performed, separated for dentition. Trial sequential analysis was used to assess risk of random errors. Strength of evidence was graded using the GRADE approach. From a total of 453 identified studies, 11 (all with high risk of bias) investigating 1094 teeth (922 patients) were included. Six studies were on primary teeth (all with carious exposures) and five on permanent teeth (carious and artificial exposures). Mean follow-up was 14months (range 3-24). Most studies used calcium hydroxide as control, comparing it to mineral trioxide aggregate (MTA) (three studies), bonding without prior etching/conditioning (two), or bonding with prior etching/conditioning, enamel matrix proteins, resin-modified glass ionomer cement, calcium sulfate, zinc oxide eugenol, corticosteroids, antibiotics, or formocresol (each in only one study). One study compared MTA and calcium-enriched cement. In permanent teeth, risk of failure was significantly decreased if MTA instead of calcium hydroxide was used (risk ratio (RR) [95% confidence intervals (CI)] 0.59 [0.39/0.90]); no difference was found for primary teeth. Other comparisons did not find significant differences or were supported by only one study. No firm evidence was reached according to trial sequential analysis. There is insufficient data to recommend or refute the use of a specific material. More long-term practice-based studies with real-life exposures are required. To reduce risk of failure, dentists might consider using MTA instead of calcium hydroxide (CH) for direct capping. Current evidence is insufficient for definitive recommendations.

Current status of direct pulp-capping materials for permanent teeth

Current status of direct pulp-capping materials for permanent teeth

Comparison of the antimicrobial activity of direct pulp-capping materials: Mineral trioxide aggregate-Angelus and Biodentine.

Purpose:To compare the antimicrobial activity of the tricalcium silicate-based Biodentine (BD) and mineral trioxide aggregate (MTA)-Angelus cement with the aid of agar diffusion test.Materials and Methods:Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecium were inoculated in the Brucella liquid medium and were incubated at 37°C for 24 h. Thereafter, 100 >μl of the liquid culture of bacteria inoculated in the Mueller-Hinton agar with spread plate technique. Petri plates were dried in room temperature. For every microorganism, 3 petri plates were prepared (12 in total). In the medium, in every petri plate, 2 holes with 5 mm diameter and 2 mm depth were made. Afterward, BD and MTA-Angelus were filled into these holes under aseptic conditions according to the instructions of the manufacturing company. Then, the plates were kept in the incubator at 37°C for 24 h, and the diameters of the inhibition zones were measured with a digital caliper.Results:Inhibition zones formed by BD against E. coli and S. aureus were significantly larger than the zones formed by MTA-Angelus (P < 0.05). However, the inhibition zones formed by MTA-Angelus against P. aureus and E. faecium were larger than the zones formed by BD (P < 0.05).Conclusion:Within the limits of the present study, tricalcium silicate-based MTA-Angelus and BD have antimicrobial activity against E. coli, S. aureus, P. aureus, and E. faecium.

Current status of direct pulp-capping materials for permanent teeth.

Direct pulp-capping is a method for treating exposed vital pulp with dental material to facilitate the formation of reparative dentin and to maintain vital pulp. Two types of pulp-capping materials, calcium hydroxide and mineral trioxide aggregate, have been most commonly used in clinics, and an adhesive resin has been considered a promising capping material. However, until now, there has been no comprehensive review of these materials. Therefore, in this paper, the composition, working mechanisms and clinical outcome of these types of pulp-capping materials are reviewed.

Clinical, radiographic, and histologic analysis of the effects of acemannan used in direct pulp capping of human primary teeth: short-term outcomes.

Acemannan has been previously reported as a direct pulp-capping agent in animal study. This natural material demonstrated its biocompatibility and enhanced reparative dentin formation. The objective of this study was to investigate the action of acemannan as a direct pulp-capping material in human primary teeth with deep caries. Forty-two deeply carious mandibular primary molars from 37 children, aged 7-11years old diagnosed with reversible pulpitis were studied. After completely removing the infected dentine, teeth with a pinpoint pulpal exposure were randomly divided into two treatment groups: acemannan or calcium hydroxide. A glass-ionomer cement base was applied to all teeth prior to restoration with stainless steel crowns. Clinical and radiographic evaluation was performed 6months post-treatment. The teeth due to exfoliate were extracted and histopathologically evaluated for inflammation, dentine bridge formation, and soft tissue organization. At 6months, the overall clinical and radiographic success rates of direct pulp capping with acemannan and calcium hydroxide at 6months were 72.73 and 70.0%, respectively. The histopathological results indicated that the acemannan-treated group had significantly better histopathological responses compared with the calcium hydroxide-treated group (p<0.05). These data suggest acemannan offers a valuable alternative biomaterial for vital pulp therapy in primary teeth.

A Randomized Controlled Study of the Use of ProRoot Mineral Trioxide Aggregate and Endocem as Direct Pulp Capping Materials: 3-month versus 1-year Outcomes

IntroductionThe purpose of this study was to assess the long-term clinical outcomes of direct pulp capping (DPC) with ProRoot MTA (Dentsply, Tulsa, OK) and Endocem (Maruchi, Wonju, Korea) as pulp capping materials. To this end, the 1-year cumulative successes of both materials were evaluated and compared with those of the 3-month outcomes in a prospective, randomized controlled trial. MethodsPatients were recruited from the Department of Conservative Dentistry of the Yonsei University Dental Hospital, Seoul, South Korea, from January to May 2013. Of the 48 teeth that met the inclusion criteria, 46 teeth were randomly allocated to either ProRoot MTA or Endocem groups (n = 23). Direct pulp capping was performed, and clinical and radiographic examinations were conducted over 1 year after the treatment. Survival analyses were conducted to compare the cumulative successes between ProRoot MTA and Endocem and to evaluate other clinical variables. ResultsForty-one teeth were recalled 1 year after the treatments (recall rate = 89.13%). There were no significant differences between the cumulative successes of ProRoot MTA and Endocem in either log-rank or Cox proportional hazard regression analyses (P > .05). Among the other clinical variables, cavity type (class I, II, III vs class V) was determined to be significant in both the log-rank test (P = .001) and Cox regression analysis (P = .006). ConclusionsBoth ProRoot MTA and Endocem exhibited similar cumulative successes as direct pulp capping materials up to 1 year. The teeth restored with class V cavities exhibited significantly lower cumulative success rates after direct pulp capping compared with the teeth restored with other types of cavities.

Clinical Outcomes for Teeth Treated with Electrospun Poly(ε-caprolactone) Fiber Meshes/Mineral Trioxide Aggregate Direct Pulp Capping

IntroductionMineral trioxide aggregate (MTA) is a biocompatible material for direct pulp capping. This study was designed to compare the clinical outcomes of pulp-exposed teeth treated with either poly(ε-caprolactone) fiber mesh (PCL-FM) as a barrier for MTA (so-called PCL-FM/MTA) or MTA direct pulp capping. MethodsSixty human vital teeth were evenly divided into 4 groups (n = 15 in each group). Teeth in groups 1 and 3 had pulp exposure <1 mm in diameter, whereas teeth in groups 2 and 4 had pulp exposure of 1–1.5 mm in diameter. Teeth in groups 1 and 2 were treated with PCL-FM/MTA direct pulp capping, and those in groups 3 and 4 were treated with MTA direct pulp capping. ResultsTeeth treated with PCL-FM/MTA direct pulp capping needed a significantly shorter mean duration for dentin bridge formation than teeth treated with MTA direct pulp capping. Moreover, teeth with pulp exposure <1.0 mm in diameter needed a significantly shorter mean duration for dentin bridge formation than teeth with pulp exposure of 1–1.5 mm in diameter after either PCL-FM/MTA or MTA direct pulp capping treatment. In addition, teeth treated with PCL-FM/MTA direct pulp capping formed an approximately 3-fold thicker dentin bridge than teeth treated with MTA direct pulp capping 8 weeks or 3 months later. Furthermore, none of the teeth treated with PCL-FM/MTA direct pulp capping showed tooth discoloration after treatment for 3 months. ConclusionsPCL-FM/MTA is a better combination material than MTA alone for direct pulp capping of human permanent teeth.

Behavior of Element Transfer and Elution in Light-cured Calcium Silicate-based Direct Pulp-capping Materials

Behavior of Element Transfer and Elution in Light-cured Calcium Silicate-based Direct Pulp-capping Materials

Hydration of Biodentine, Theracal LC, and a Prototype Tricalcium Silicate–based Dentin Replacement Material after Pulp Capping in Entire Tooth Cultures

IntroductionThe calcium-releasing ability of pulp-capping materials induces pulp tissue regeneration. Tricalcium silicate–based materials produce calcium hydroxide as a by-product of hydration. Assessment of hydration and calcium ion leaching is usually performed on samples that have been aged in physiological solution for a predetermined period of time. The hydration and activity of the materials in vivo may not be similar to those displayed in vitro because of insufficient fluid available in contact with dentin. The aim of this research was the assessment of hydration of Biodentine, Theracal LC, and a prototype radiopacified tricalcium silicate–based material after pulp capping and to compare it with direct hydration in an aqueous solution. MethodsThe extent of hydration of Biodentine, Theracal LC, and a prototype radiopacified tricalcium silicate–based material with a similar composition to Biodentine but not incorporating the additives was assessed by scanning electron microscopy and energy dispersive spectroscopy of polished specimens after being allowed to hydrate in Hank's balanced salt solution for 14 days. The extent of hydration was compared with material hydration when used as direct pulp capping materials by using a tooth culture model. Material activity was also assessed by x-ray diffraction analysis to investigate the deposition of calcium hydroxide by the materials, and calcium ion leaching in Hank's balanced salt solution was assessed by ion chromatography. ResultsBiodentine and the prototype tricalcium silicate cement hydrated and reaction by-products were deposited in the cement matrix both after pulp capping and when incubated in an aqueous solution. Calcium hydroxide was formed, and calcium ions were leached in solution. Theracal LC hydration was incomplete because of the limited moisture diffusion within the material. Thus, no calcium hydroxide was produced, and a lower calcium ion leaching was recorded. ConclusionsTheracal LC had a heterogeneous structure with large unhydrated particles because not enough moisture was present to allow hydration to proceed. Biodentine composition was shown to be optimized, and the environmental conditions did not affect material microstructure. Biodentine exhibited formation of calcium hydroxide and calcium ion leaching, which are beneficial to the dental pulp.

In Vitro Cytotoxicity Evaluation of Four Vital Pulp Therapy Materials on L929 Fibroblasts

The aim of this study was to evaluate cytotoxicity of direct pulp capping materials such as Dycal, Life, ProRoot MTA, and Super-Bond C&B on L929 fibroblasts. Freshly mixed or set materials were prepared and eluted by incubation with cell culture medium for working time period (fresh) or for 6 hours (set). The cells were exposed to media containing elutes for 24 hours, after which the cell survival was evaluated by MTS assays. In freshly mixed materials, average ± standard deviation % cell viabilities were 40.2 ± 14.0%, 43.7 ± 16.0%, 72.9 ± 12.7%, and 66.0 ± 13.6% for Dycal, Life, ProRoot MTA, and Super-Bond C&B, respectively. There was no statistical difference in cell viabilities among material groups, whereas in set materials, the cell viabilities were 48.7 ± 14.8%, 37.2 ± 10.6%, 46.7 ± 15.2%, and 100 ± 21.9% for Dycal, Life, ProRoot MTA, and Super-Bond C&B, respectively. Super-Bond C&B showed more cell viabilities than the other three material groups (P < 0.05). The four vital pulp therapy materials had similar cytotoxicity when the materials were fresh. Super-Bond C&B was less cytotoxic than Dycal, Life, and ProRoot MTA after the materials were set, which suggests the use of SB-C&B in future in vivo clinical investigations.

Characteristics improvement of calcium hydroxide dental cement by hydroxyapatite nanoparticles. Part 1: Formulation and microstructure

Calcium hydroxide cement (CHC), which is a direct pulp-capping material, has been widely used for several decades. In spite of the well-known advantages of CHCs, they have some disadvantages as well, such as high solubility, no inherent adhesive qualities, and low mechanical strength. Previous studies were undertaken to improve these deficiencies by implementing changes to modify the conventional CHCs. The aim of the present research is to demonstrate the potential rectification of the aforementioned deficiencies of the commercially available CHCs by adding hydroxyapatite (HA) nanoparticles without lessening their advantages. Here, the synthesized HA nanoparticles were added into the CHCs in two different portions of 3 and 7 wt%. A scanning electron microscope was used to observe and analyze the microstructure, and X-ray energy dispersive analysis was used to analyze the elemental composition of the new CHCs. In addition, setting time, mechanical strength, pH, calcium (Ca) release, and antibacterial behavior were measured to assess how HA nanoparticles influence the characteristics of CHCs. The results showed that adding 3 wt% HA nanoparticles can optimally improve the mechanical strength of the cement and increase the Ca release rate as a mineralization promoter without reducing the antibacterial behavior.

Pulpo-dentin complex response after direct capping with self-etch adhesive systems

The purpose of the present study was to evaluate morphologically the response of feline teeth pulp to direct pulp capping with two different self-etch adhesive systems. Twenty-four cavities in feline teeth were mechanically exposed and assigned to one of two experimental groups: AdheSE + Tetric Ceram (the ASE group), or Adper Prompt L-Pop + Filtek Supreme (the APLP group). There was also a control group Dycal Ca(OH)2 liner + Amalgam (the CH group eight teeth), and six teeth were used as an intact control group. The animals were sacrificed after 40 days. The teeth were removed and processed for standard histological evaluation, using a scoring system for inflammatory cell response, pulp tissue disorganisation, reparative tissue formation, and the presence of bacteria. Statistical analysis revealed no significant differences between the ASE and APLP selfetching resin systems during the observation period. The majority of the specimens presented inflammatory pulp response with tissue disorganisation and a lack of dentinal bridge formation. CH capping resulted in a significantly smaller inflammatory pulp response and a considerably higher incidence of reparative dentin formation. ASE and APLP were comparably effective as direct pulp capping materials, but their application resulted in significantly greater pulp tissue damage than CH capping. Further in vivo human studies are necessary to determine which adhesive resin systems should be clinically used for direct pulp capping without incurring severe damage to the pulpal tissue.

Pulpo-dentin complex response after direct capping with self-etch adhesive systems

The purpose of the present study was to evaluate morphologically the response of feline teeth pulp to direct pulp capping with two different self-etch adhesive systems. Twenty-four cavities in feline teeth were mechanically exposed and assigned to one of two experimental groups: AdheSE + Tetric Ceram (the ASE group), or Adper Prompt L-Pop + Filtek Supreme (the APLP group). There was also a control group Dycal Ca(OH)(2) liner + Amalgam (the CH group eight teeth), and six teeth were used as an intact control group. The animals were sacrificed after 40 days. The teeth were removed and processed for standard histological evaluation, using a scoring system for inflammatory cell response, pulp tissue disorganisation, reparative tissue formation, and the presence of bacteria. Statistical analysis revealed no significant differences between the ASE and APLP self-etching resin systems during the observation period. The majority of the specimens presented inflammatory pulp response with tissue disorganisation and a lack of dentinal bridge formation. CH capping resulted in a significantly smaller inflammatory pulp response and a considerably higher incidence of reparative dentin formation. ASE and APLP were comparably effective as direct pulp capping materials, but their application resulted in significantly greater pulp tissue damage than CH capping. Further in vivo human studies are necessary to determine which adhesive resin systems should be clinically used for direct pulp capping without incurring severe damage to the pulpal tissue.

Efficacy of polyphasic calcium phosphates as a direct pulp capping material

Objectives Polyphasic calcium phosphates (Poly-CaP), a complex of hydroxyapatite (HAp) and soluble calcium phosphates including α-tricalcium phosphate and tetracalcium phosphate, demonstrate promoting effects on hard tissue formation by osteoblasts. We hypothesized that a Poly-CaP block with a soluble calcium phosphates phase on one side and an insoluble HAp phase on the other side is useful for vital pulp therapy as it may promote dentin regeneration and provide the surface effective to achieve sealing. The purpose of this study was to investigate the efficacy of Poly-CaP as a direct pulp capping material by examining the Ca-release profile, the in vivo ability to induce reparative dentinogenesis, and the bonding of HAp surface with adhesive systems. Methods Poly-CaP prepared by annealing crude HAp disc was immersed in buffer solution at pH 7.4 or 4.0, and the concentration of Ca released was measured until 15 days. The pulp of 9-week-old Wister rat molar was exposed and capped with Poly-CaP or HAp block, and dentin bridge formation and pulpal inflammation was evaluated histopathologically after 2 or 4 weeks. Etch & rinse or self-etching adhesive was bonded to HAp surface, and the interface was observed using SEM. Results Poly-CaP exhibited continuous release of Ca with significantly greater amount than HAp at both pH conditions ( P < 0.05, Student's t-test). Animal tests demonstrated formation of complete dentin bridge at higher rate for Poly-CaP compared with HAp after 4 weeks ( P < 0.05, Steel–Dwass test). Impregnation of resin into etched HAp surface, with production of intimate contact at the bonding interface, was seen for all adhesives. Conclusions Poly-CaP is a potentially useful material for direct pulp capping with the advantages to promote dentin bridge formation and to provide tight sealing by adhesives.