| Abstract|| |
Background: Formocresol remains to be the preferred medicament in pulpotomy, despite the concerns regarding tissue devitalization and systemic toxicity. Several materials were used as alternatives, but none proved significantly advantageous. Of recent, calcium phosphate cement (CPC) has been projected as an ideal pulpotomy material considering its tissue compatibility and dentinogenic properties. This study explores the suitability of a CPC formulation for pulpotomy, in comparison with formocresol.
Materials and Methods: This comparative case study included 10 children (8-12 age group) having a pair of non-carious primary canines (both maxillary and mandibular) posted for extraction. Pulpotomy was performed with CPC in the right canines and formocresol in the left and sealed with IRM ® (Dentsply). The teeth were extracted at 70 ± 5 days and sectioned and stained for the histopathological evaluation. Parameters such as pulpal inflammation, tissue reaction to material, dentine bridge formation, location of dentine bridge, quality of dentine formation in bridge, and connective tissue in bridge etc. were evaluated.
Results: The histological assessment after 70 days showed no statistically significant difference between the two groups in any of the parameters. However, CPC gave more favorable results in pulpal inflammation, with a lower score of 1.6 against 2.6 for formocresol. CPC samples showed better formation of dentine bridge in quantity and quality. The mean scores for CPC for the extent of dentine bridge formation, quality of dentine bridge and connective tissue in the bridge, were 2.0, 1.4, and 1.2 respectively, whereas the corresponding values for formocresol were 0.8, 0.2, and 1.0.
Conclusion: CPC is more compatible to pulp tissues than formocresol and it shows good healing potential. CPC is capable of inducing dentine formation without an area of necrosis.
Keywords: Alloplast materials, bone graft, calcium phosphate cement, pulpotomy
|How to cite this article:|
Jose B, Ratnakumari N, Mohanty M, Varma H K, Komath M. Calcium phosphate cement as an alternative for formocresol in primary teeth pulpotomies. Indian J Dent Res 2013;24:522
Pulpally involved deciduous teeth with carious, mechanical and traumatic exposures require pulpotomy, which involves the amputation of the infected part of the coronal pulp followed by the placement of a suitable medicament or dressing. The procedure preserves the vitality of the remaining radicular pulp and helps in retaining the tooth in healthy state until normal exfoliation. Additional advantages are preservation of the dental arches and prevention of space loss and malocclusion.  The success of pulpotomy as is evident, depends on the medicament or dressing applied. Therefore, the pulpotomy material should satisfy stringent biocompatibility requirements. The vitality of the radicular pulp should not be affected by its presence, nor should it cause any breakdown of periradicular supporting tissues or any harm to the succedaneous teeth. Preferably, the material should promote the odontoblast proliferation in the dentine chamber. 
|How to cite this URL:|
Jose B, Ratnakumari N, Mohanty M, Varma H K, Komath M. Calcium phosphate cement as an alternative for formocresol in primary teeth pulpotomies. Indian J Dent Res [serial online] 2013 [cited 2015 Mar 31];24:522. Available from: http://www.ijdr.in/text.asp?2013/24/4/522/118370
The pioneering medicament used for pulpotomy was formocresol, a mixture of formaldehyde and cresol.  It was first introduced by Sweet in the 1930s,  owing to its bactericidal and tissue fixative properties. Since then, formocresol pulpotomy technique has been practiced widely world over and a sizable literature is available on its different aspects.  The overall clinical success rate of more than 90% is reported for formocresol, although histologically it is less and variable. There are histological evidences in animals and humans showing that formocresol initiates devitalization process in the remaining root canal tissue. , Along with this fact, concerns about safety haunted this material persistently for the past three decades. ,
The formaldehyde component of formocresol was seen to get distributed systemically after pulpotomy, in animal experiments. , Mutagenic and carcinogenic effects of formaldehyde exposure have also been demonstrated in a number of animal studies.  Formocresol was reported to cause antibody formation leading to immune sensitization in dogs.  Statistically significant increase in chromosomal aberrations has been reported in one-tenth of the children who received single formocresol pulpotomy.  These findings led to the reclassification of formaldehyde as a known human carcinogen by the International Agency for Research on Cancer of the World Health Organization in 2004.  It raised serious questions about continuing the use of formocresol and prompted the dental fraternity to explore alternatives.  Several medicaments have been projected as substitutes for formocresol, with varying success. 
Gluteraldehyde, another agent with tissue fixative properties, emerged as a pulpotomy material in mid 1970s. It appeared to be a better choice because of the low chances of out-diffusion through apical foramen.  Though there were evidences for the systemic absorption of gluteraldehyde after pulpotomy, it was shown to be less toxic with low potential of allergic response and mutagenicity. The overall clinical success rate of gluteraldehyde was in between 74% and 100% in the follow-up periods ranging from 6 months to 42 months. However, it did not replace formocresol in pulpotomy because safety concerns were not fully cleared and reports on success were conflicting. 
Two decades back, ferric sulfate was put in use, which turned out to be at par with formocresol in clinical and radiographic success rates.  The material was observed to evoke a local, but reversible, inflammatory response in oral soft-tissues.  Ferric sulfate was apparently free from concerns about toxic or harmful effects and hence considered as a viable substitute to formocresol.  However, the long-term outcomes of primary tooth root canal therapy were inferior to those of formocresol. 
Calcium hydroxide  and zinc-oxide-eugenol (ZOE) were also used as pulpotomy medicaments. Non-reinforced ZOE, when applied for canal filling, was observed to invoke a localized inflammatory response in soft-tissue.  Neither calcium hydroxide nor ZOE found success in the primary teeth pulpotomies. 
Mineral trioxide aggregate (MTA), evolved in the past decade, has shown certain promise as a pulpotomy medicament.  A number of recent human studies with follow-up periods from 6 months to 74 months, demonstrate the performance of MTA to be at par with or better than formocresol in the pulpotomy of primary teeth. The lack of undesirable side-effects is a favorable factor here. Some authors expect MTA to replace formocresol in the pediatric pulpotomy in the foreseeable future, despite the cost factor. 
A potential alternative material for pulp capping, which raises a lot of hope is calcium phosphate cement (CPC). This falls in the class of hydraulic cements, which self-harden to hydroxyapatite (HA), the bone mineral. Several formulations of CPC have been successfully designed for various orthopedic and dental applications. , CPCs possess the combination of biocompatibility, osteoconductivity and mouldability. Moreover, they are non-toxic and non-immunogenic and do not have any mutagenic or carcinogenic potential. Apparently, CPC satisfies the essential characteristics of a pulpotomy material and has been suggested to be ideal for pulp capping. 
Animal studies indicate that CPC has potential applications in pulpal procedures. In 1996, Chaung et al.,  compared CPC and pure calcium hydroxide in direct capping of the exposed pulp in monkeys. Yoshimine and Maeda,  and Sena et al.,  used different formulations of CPC to explore the response of rat pulp, in comparison with calcium hydroxide. Both the studies recorded favorable results for CPC, including the formation of reparative dentine in the latter. In a more recent study, Zhang et al., evaluated a CPC material incorporating microspheres loaded with transforming growth factor-β1 for pulp capping, in goat incisors. New dentin formation was seen in all the samples.  Despite the success in animal studies, any convincing human data is lacking regarding its application in pulp capping procedures.
In this background, it is relevant to investigate the human pulpal response to CPC in comparison with formocresol. The present study has been designed to observe the performance of CPC when used as a pulpotomy material, in a population of 10 patients. An indigenous CPC has been used in this study. , The main objective was to assess the potential of CPC as an alternative to formocresol in pulpotomy. The materials were applied on the pulp in a matched pair of primary canines in each patient scheduled for extraction, through standard pulpotomy procedures. The pulpal responses were compared histologically after extraction.
| Materials and Methods|| |
The study subjects were selected from the children in the age group of 8-12 year with primary canines indicated for serial extraction, at the Department of Pedodontics, Government Dental College, and Trivandrum. The study has been planned in accordance with the ethical stipulations of the Helsinki Declaration of 1975 (as revised in 2000, available at URL: http://www.wma.net/e/policy/17-c_e.html). The necessary regulatory permission has been obtained from the Ethics Committee of the Institution prior to the study. As the subjects were minors, the informed consent was taken from the parents before the study.
The following inclusion criteria were observed in general in the selection of patients: (i) The patient is in good general health and free of any systemic disease, (ii) the teeth identified for the study are free of caries, hypoplastic defects or any malformations, (iii) no apparent mobility for the tooth to finger pressure, (iv) teeth are free of any periodontal problems, and (v) no history of pain/tenderness to percussion. The specific criteria for selection was that the patient should have a pair of non-carious primary canines (either maxillary or mandibular) posted for extraction. The study population was 10 and each of them received pulpotomy procedures with the test material (CPC) in the right canine and the control material (formocresol) in the left canine.
The CPC used has been supplied by Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST) Trivandrum. The cement has undergone evaluation for safety and efficacy as per ISO 10993 , and approved for human clinical use by the Institutional Ethics Committee of SCTIMST. The packing of the CPC consisted of a dry powder pouch and a vial with wetting solution, both sterilized. The formocresol formulation used was Tresol (Vishal Dentocare, India) which contained 35% tricresol and 19% formalin at 40% concentration.
Local anesthesia was given through standard technique using Adrenox, each ml of which contained lignocaine hydrochloride IP 21.3 mg, adrenaline bi-tartrate equivalent to adrenaline IP 0.0125 mg, sodium metabisulphite IP 0.1% w/v, water for injection IP q.s. The teeth were isolated and the access cavities were prepared on the lingual/palatal surface with a number-4 round bur. A high speed hand piece with water spray was used for the purpose. Roof of the pulp chamber was removed and coronal pulp tissue was scooped using a spoon excavator. Pulp chamber was washed with saline to clear off the debris. Medicaments were placed after obtaining hemostasis through the application of sterile cotton pellets.
CPC has been prepared by mixing the powder and the wetting medium, in soft putty consistency. This is placed in the right canine in 1-2 mm thick layer to obtain a conformal filling over the exposed pulp. Cotton dampened with formocresol was applied on the exposed pulp in the left canines for 5 min. The sealing was carried out by Intermediate Restorative Material (IRM supplied by Dentsply Caulk).
Post-operatively, instructions were given to the subjects to report in case of any adverse reactions. They were called back for extractions at 70 (±5) days, the period stipulated for Pulp and Dentine Usage Test in the ISO Standard for Test Methods for Dental Materials (ISO 7405). The extractions were carried out under local anesthesia as given during the intervention. The extracted teeth were cleaned in distilled water and about 2 mm of the apices were cut-off using a sawing tool, to ensure the percolation of the fixative into the pulp tissue. Each of the teeth was then placed separately in small vials filled with 10% buffered formalin and labeled with corresponding sample number. The fixation in formalin was continued for 48 h.
The fixed teeth specimens were dehydrated in ascending grades of alcohol. The process started with 70% alcohol and then continued successively in 90% and 95% concentrations, with final washing in absolute alcohol. Then the clearing was carried out twice in alcoholic acetone (1:1 v/v) mixture.
The specimens were embedded in poly-methyl methacrylate (PMMA) for sectioning, after treating with washed methyl methacrylate monomer to ensure infiltration. The embedding was carried out by placing them vertically in glass vials and pouring the monomer mixed with initiator. The vials were subsequently kept in a vacuum oven for 72 h for the completion of polymerization and then broken off to release the PMMA blocks. The sectioning of the blocks was carried out using a high precision diamond saw (ISOMET 5000, Buehler). Multiple thin saggital sections of thickness 100-150 μm were cut and further thinned by polishing in a grinder-polisher machine (ECOMET, Buehler) with 600-800 grit abrasive sheets.
The sections were coded appropriately to enable blind analysis. The staining of the sections was carried out with both Stevenel's Blue and H and E. This staining strategy was adopted to observe inflammatory cells, connective tissues, and newly calcified dentine. All were examined under a stereomicroscope (Leica) and trinocular transmitted light microscope (NIKON E600), recording the images using a digital camera.
The evaluation and scoring of the images of the sections were carried out using the following criteria (modified scoring system adapted from Stanley  ):
Pulpal inflammation: No inflammation: 0; mild inflammatory infiltrate: 1; moderate inflammatory infiltrate: 2; heavy inflammatory infiltrate: 3; abscess: 4.
Tissue reaction to material: No macrophages/giant cells adjacent to material: 0; mild infiltration of macrophages/ giant cells: 1; moderate infiltration of macrophages/giant cells: 2; severe infiltration of macrophages/giant cells: 3.
Dentine bridge formation: No presence of bridge formation: 0; bridge lesser than 25%: 1; bridge in the range 25% and 50%: 2; bridge in the range 50% and 75%: 3; bridge higher than 75%: 4.
Location of dentine bridge: No bridge formation: 0, bridge at the interface of exposure pulp: 1; bridge away from the interface of exposure pulp: 2; combination: 3.
Quality of dentine formation in bridge: No presence of bridge formation: 0; no tubules present: 1; irregular pattern of tubules: 2; regular pattern of tubules: 3.
Connective tissue in bridge: No bridge formation: 0, no connective tissue: 1; connective tissue lesser than 25%: 2; connective tissue between 25% and 50%: 3; connective tissue between 50% and 75%: 4; Connective tissue higher than 75%: 5.
| Results|| |
Post-operative clinical examination period was uneventful. None of the cases showed pain or abscess during the examination period.
The histological sections of the teeth were evaluated by the histopathologist (the third author) using the modified scoring system adapted from Stanley.  In all cases, the capping agent was identified as a granular grey material and the sealer was identified as a homogenous grey to blackish material. Odontoblast layer adjacent to the capping agent was disorganized in the both the groups. None of the cases showed impaction of the capping agent. One case in the CPC group showed tissue reaction to the material.
In the formocresol group, a layer of dense and homogenous eosinophilic tissue was present in the part of the pulp subjacent to the exposure site. Heavy inflammation was seen with neutrophils, lymphocytes and foamy macrophages in six cases. Typical histological images are shown in [Figure 1] and [Figure 2]. One case had a score of 4, indicating abscess formation. Two cases showed moderate inflammation and one was free from inflammation.
|Figure 1: Histological section showing heavy chronic inflammation of the pulp treated with formocresol (Stevenel's blue staining). The frame marked in Figure 1a with red is shown magnified in Figure 1b. Numerous foamy macrophages, lymphocytes and neutrophils and cell debri are seen|
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|Figure 2: Severe inflammation of the pulp in a formocresol sample (H and E). The frame marked in Figure 2a with red is shown magnified in Figure 2b|
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In the CPC group, pulp tissue below the capping material showed varied degrees of inflammation. Four cases did not have any inflammation, whereas moderate inflammation was present in two cases [Figure 3]. The remaining four had heavy inflammation with neutrophils and foamy macrophages.
|Figure 3: Moderate inflammation of the pulp in a calcium phosphate cement treated sample (Stevenel's blue staining). The coronal pulp (in the frame marked with red in Figure 3a) is shown magnified in Figure 3b|
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In many of the samples in the formocresol group, the apical pulp was affected as seen in [Figure 4]. The CPC group showed normal and vital pulp in the apical part [Figure 5].
|Figure 4: Inflammation found in the lower pulp in a formocresol sample (Stevenel's blue, ×10)|
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|Figure 5: Normal vital pulp apically in a sample treated with calcium phosphate cement (Stevenel's blue, ×40)|
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Two cases in the formocresol group showed poorly calcified dentine bridge formation. The locations of both were not at the interface of exposure of pulp, but at the apical third of the root canal, as could be found in [Figure 6]. Both were greater than 75%, but without tubules. More than 75% connective tissues were found in both the bridges.
|Figure 6: Poorly calcified dentine bridge formation in a sample treated with Formocresol (Stevenel's blue). The frame marked in Figure 6a with red is shown magnified in Figure 6b. The presence of fibroblasts is to be noted|
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Patchy areas of mineralizing reparative dentine were noted along the dentine wall in most of the cases in CPC group. Six cases showed dentine bridge formation. In three cases, the dentine bridge formed at the exposure site and in the other three, below the exposure site. Among these, four cases showed complete or nearly-complete dentine bridge formation. Three of the bridges had regular dentine tubules in them. In most of the cases, dentine bridge did not contain connective tissue.
Out of the six cases of dentine bridge formation in the CPC group, four were more than 75% and two were in between 25% and 50%. Three of them were located at the interface of exposure and the other three were in the aisle. Three showed regular tubules, two had irregular tubules and one was devoid of tubules. Three had no connective tissue, two had connective tissue less than 25% and one had connective tissue more than 75%. A case of bridge formation adjacent to the material could be found in [Figure 3]a (lower middle portion). Tubule formation is observed, but incomplete. [Figure 7] shows the formation of a thick bridge below the site in which the mineralization starts from the dentine wall. The bridge is continuous but not fully calcified. A matured dentine bridge could be seen in [Figure 8], which has grown from the walls, but not connected in the middle. The thickness is more than 100 microns and tubules are present. Signs of inflammation of the pulp are present in the picture.
|Figure 7: Dentine bridge formation in the boundary of calcium phosphate cement (Stevenel's blue). The frame marked in Figure 7a with red is shown magnified in Figure 7b|
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|Figure 8: Dentine bridge of good quality in calcium phosphate cement sample (Stevenel's blue), which is not connected in the middle. The right portion of the bridge (frame marked with red in Figure 8a) is shown magnified in Figure 8b. Signs of inflammation are present in the pulp|
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The presence of connective tissue in the bridges indicates that they had not been completely mineralized. This can be explained by the fast initial disorganized formation of reparative dentine that engulfs cellular inclusions. In due course, the reparative dentine becomes more mineralized at the surface and more regular as the bridge matures and begins forming tubular dentine.
The results of the statistical analysis of the scores of parameters for both control and test groups are given in [Table 1]. It could be seen that there is no statistically significant difference between the formocresol group and the CPC Group in any of the parameters. However, CPC gives more favorable results with regards to pulpal inflammation (mean score of 1.6 against 2.6 for formocresol), dentine bridge formation (mean score of 2 against 0.80 for formocresol), quality of dentine bridge (mean score 1.4 against 0.2 for formocresol) and connective tissue in the bridge (mean score 1.2 against 1.0 for formocresol).
| Discussion|| |
The best criteria for judging the effectiveness of a medicament for vital pulp therapy is assessing the response it produces in the pulp. The present study compares the efficacy of the selected pulpotomy medicaments (FI-CPC and formocresol) through histopathologic evaluation of the pulp in human deciduous teeth.
The study reveals that formocresol, the current gold standard in primary tooth pulpotomy, imparts severe inflammation with tissue necrosis and abscess formation. Dense layers of eosinophilic fixed zone sub-adjacent to formocresol followed by an inflammatory zone containing neutrophils, macrophages, and lymphocytes were present in all cases. These are in accordance with the reported reaction of the dental pulp to formocresol , and re-emphasize the fact that the fixation of pulp tissue using formocresol is never complete. The cytotoxic and inflammatory actions of formocresol and its inhibitory effect on the healing process have been elaborated by several workers. ,
Despite the deleterious effect of formocresol on the adjacent layers of the pulp, the apical portion of the pulp remained vital at 70 days after pulpotomy. This is in contradiction with the early study by Berger  in which a complete loss of vitality and formation of a fibrotic granulation tissue in the apical-3 rd of the canal after pulpotomy with formocresol was identified. However, later, some other workers observed vitality of the apical pulp in a similar procedure. ,
In the results of the CPC group, the pulp tissue showed varying degrees of inflammation without initial necrosis, followed by normal healthy vital pulp. This agrees with the results of both in vitro and animal studies ,,, using calcium phosphate based pulp capping materials. The mean pulpal inflammation score recoded was 1.6 for CPC, against 2.6 for formocresol. The favorable response of pulpal tissue to CPC can be attributed to its biocompatibility. This FI-CPC is an apatitic cement, which get converted to HA, the bone mineral.  Biocompatibility studies have established that FI-CPC has excellent soft-tissue compatibility and it encourages hard tissue regeneration. 
The present results give a clear indication of hard tissue formation in the pulp of human canine teeth apposing the CPC material. Many studies in animals have identified this phenomenon with calcium phosphate based materials. ,,, Formation of dentinal reparatory bridges were observed directly on the calcium phosphate material without initial necrosis, which occurs inevitably when Ca(OH) 2 is used.  Chaung et al.,  compared CPC and pure calcium hydroxide as direct capping agents on the deliberately exposed pulp tissue of 60 teeth in five monkeys. Histological comparisons after 12, 20 and 24 weeks showed that both materials produced similar responses with regard to their biocompatibility and induction of hard tissue barrier formation. CPC appeared superior to pure calcium hydroxide with reference to the self-setting ability and fair compressive strength. In an experiment comparing a phosphate cement and calcium hydroxide cement in direct pulp capping of the rat maxillary incisors, Yoshimine and Maeda  observed (tetra) CPC to elicit dentine bridge formation.
The formation of reactionary and reparative dentin has been extensively reviewed.  Various studies are available regarding the nature and phenotype of the cells involved in repair, their molecular regulation, and the secretory behavior, which gives rise to various mineralized matrices.  Téclès et al.,  had demonstrated that perivascular progenitor/stem cells can proliferate in response to dentin injury. Alliot-Licht et al.,  based on evidence from cultured human pulpal cells, have suggested that the progenitor cells for the new-odontoblast like cells could be pericytes or pericyte progenitor cells. It is also possible that fibroblasts may re-differentiate as odontoblasts. The presence of solid substrate-matrix (the base onto which pulp cells adhere and get transformed into odontoblast-like cells), is needed for reparatory dentinogenesis. It was found that pulp fibroblasts in the proximity of the damaged tissue induced synthesis and secretion of fibrodentinal matrix.  Formation of fibrodentine is considered essential as the first matrix zone, which develops tubular dentine on mineralization. The chemical nature of CPC (apatitic) may allow it to stimulate odontoblasts, thus promoting the formation of dentine bridges.
The study by Yildirim et al.,  seems relevant here, in which different calcium phosphate biomaterials such as HA, beta tricalcium phosphate (TCP), and a combination of these (TCP + HA) were used for dental pulp capping in dogs. TCP + HA group showed some catabolic and anabolic evidences simultaneously. Macrophages and multi-nucleated giant cell formation were present around the material, which were attributed to phagocytic processes. In addition, an increased capillary support and mesenchymal cell density in the same location were observed. These evidences indicate that, new hard tissue formation could take place along with the degradation through phagocytic processes, in a simultaneous manner.
In the present study, poorly calcified dentine bridge with connective tissue was observed to form in two cases in the formocresol group. This finding is consistent with various previous studies. Calcific barrier formation occurred after formocresol pulpotomies in primates.  Rølling and Lambjerg-Hansen  noted that the root canal calcification is a typical histological response following formocresol pulpotomy. High percentage of root canal obliteration may be the result of exaggerated odontoblastic activity, eventually due to irritation caused by the fixative on a chronically inflamed radicular pulp.
However, the concept of dentinal bridging is a controversial issue because the presence of a bridge does not necessarily imply that the pulp tissue is healthy. It can be viewed as both a healing response and a reaction to irritation.  The formation of an intact dentine bridge provides natural protection for the pulp against the micro-leakage of bacteria and leaching of particles from capping materials from infiltrating into pulp tissues.  However, this may not hold true at the early stages of bridge formation, when it tends to be permeable.
Apart from the use of medicament, the long-term success in pulpotomy may be affected by the temporary restoration, due to the possibility of micro-leakage.  In a study of the role of restorations in emergency pulpotomies of primary molars, Guelmann et al.,  found that stainless steel crowns provided more clinical success (86%) when compared to IRM only (61%) or IRM and Ketac Molar combined (77%). However, in the present study, IRM was used as the restoration material. The choice was based on the short term nature of the study, easy availability, convenience of handling, and minimal chair time requirement. No sabotaging event occurred in any of the case under the study.
Some investigators  had pointed out certain limitation in histological studies with saggital sectioning. It is not always possible to section exactly along the perpendicular axis of the tooth when it is embedded. This limits the perfection of scoring the sections. Histological sections would not allow unequivocal diagnosis of complete barrier formation unless serial sections are used. Furthermore, it is mentioned that histologic demonstration of only one section through a dentine bridge following capping of an exposed pulp is not by itself proper criteria for assessing the long-term pulpal healing.
| Conclusion|| |
CPC, apparently, is an ideal pulpotomy material considering its tissue compatibility and dentinogenic properties reported. The present study explores the suitability of a CPC formulation (FI-CPC) as a pulpotomy medicament, in comparison with formocresol. In the study, pulpotomies were performed in 10 children in the 8-12 age group having a pair of non-carious primary canines (both maxillary and mandibular) posted for extraction. CPC has been applied in the right canines and formocresol in the left, followed by sealing with IRM. The teeth were extracted at 70 ± 5 days and sectioned and stained for histopathological evaluation of various parameters using accepted scoring system.
A comparative statistical evaluation of the scores showed no significant difference between the two groups. However, CPC gave more favorable results in pulpal inflammation, with a mean score of 1.6 against 2.6 for formocresol (P value 0.143). CPC showed good dentine bridge formation with a mean score of 2, whereas formocresol had 0.80 (P value 0.190). The mean score for CPC in quality of dentine bridge was 1.4, against 0.2 for formocresol (P value 0.075) and that in the case of connective tissue in the bridge was 1.2 against 1.0 for formocresol (P value 0.280). These differences in the parameters may have clinical implications in a larger sample size.
The histology results show that CPC, when used in pulpotomy, induces initial healing response and gets replaced with the reparative dentine. CPC material contains HA which is tissue-compatible and osteoconductive. Presumably the material is serving as a bio-resorbable scaffold for the differentiating cells to attach and secrete mineralized tissue. CPC was also seen to preserve the normal histological pulp patterns and pulp vitality in human deciduous teeth. These qualities indicate that CPC is a better pulpotomy material compared to formocresol.
However, it may not be possible to draw a conclusive opinion from the present study because of the small sample size and limited period of follow-up. A long-term follow-up with higher population of subjects is necessary to confirm the real efficacy of CPC as a pulpotomy medicament.
| References|| |
|1.||Milledge JT. Endodontic therapy for primary teeth. In: Ingle JI, Bakland LK, Baumgartner JC, editors. Ingle's Endodontics. 6 th ed. Hamilton, Ontario: BC Decker; 2008. p. 1400. |
|2.||Sweet CA. Treatment of vital primary teeth with pulpal involvement-therapeutic pulpotomy. J Colorado State Dent Assoc 1955;33:10-4. |
|3.||Berger JE. A review of the erroneously labeled "mummification" techniques of pulp therapy. Oral Surg Oral Med Oral Pathol 1972;34:131-44. |
|4.||Loos PJ, Straffon LH, Han SS. Biological effects of formocresol. ASDC J Dent Child 1973;40:193-7. |
|5.||Lewis B. Formaldehyde in dentistry: A review for the millennium. J Clin Pediatr Dent 1998;22:167-77. |
|6.||Casas MJ, Kenny DJ, Judd PL, Johnston DH. Do we still need formocresol in pediatric dentistry? J Can Dent Assoc 2005;71:749-51. |
|7.||Pashley EL, Myers DR, Pashley DH, Whitford GM. Systemic distribution of 14C-formaldehyde from formocresol-treated pulpotomy sites. J Dent Res 1980;59:602-8. |
|8.||Ranly DM. Assessment of the systemic distribution and toxicity of formaldehyde following pulpotomy treatment: Part one. ASDC J Dent Child 1985;52:431-4. |
|9.||Block RM, Lewis RD, Sheats JB, Burke SG. Antibody formation to dog pulp tissue altered by formocresol uithin the root canal. Oral Surg Oral Med Oral Pathol 1978;45:282-92. |
|10.||Zarzar PA, Rosenblatt A, Takahashi CS, Takeuchi PL, Costa Júnior LA. Formocresol mutagenicity following primary tooth pulp therapy: An in vivo study. J Dent 2003;31:479-85. |
|11.||Ketley CE, Goodman JR. Formocresol toxicity: Is there a suitable alternative for pulpotomy of primary molars? Int J Paediatr Dent 1991;1:67-72. |
|12.||Waterhouse PJ. Formocresol and alternative primary molar pulpotomy medicaments: A review. Endod Dent Traumatol 1995;11:157-62. |
|13.||Davis MJ, Myers R, Switkes MD. Glutaraldehyde: An alternative to formocresol for vital pulp therapy. ASDC J Dent Child 1982;49:176-80. |
|14.||Feigal RJ, Messer HH. A critical look at glutaraldehyde. Pediatr Dent 1990;12:69-71. |
|15.||Loh A, O'Hoy P, Tran X, Charles R, Hughes A, Kubo K, et al. Evidence-based assessment: Evaluation of the formocresol versus ferric sulfate primary molar pulpotomy. Pediatr Dent 2004;26:401-9. |
|16.||Shaw DH, Krejci RF, Kalkwarf KL, Wentz FM. Gingival response to retraction by ferric sulfate (Astringedent). Oper Dent 1983;8:142-7. |
|17.||Schröder U, Szpringer-Nodzak M, Janicha J, Wacinska M, Budny J, Mlosek K. A one-year follow-up of partial pulpotomy and calcium hydroxide capping in primary molars. Endod Dent Traumatol 1987;3:304-6. |
|18.||Huang TH, Ding SJ, Hsu TZ, Lee ZD, Kao CT. Root canal sealers induce cytotoxicity and necrosis. J Mater Sci Mater Med 2004;15:767-71. |
|19.||Good DL. Effects of materials used in pediatric dentistry on the pulp: A review of the literature. J Calif Dent Assoc 1999;27:861-7. |
|20.||Eidelman E, Holan G, Fuks AB. Mineral trioxide aggregate vs. formocresol in pulpotomized primary molars: A preliminary report. Pediatr Dent 2001;23:15-8. |
|21.||Larsson S, Bauer TW. Use of injectable calcium phosphate cement for fracture fixation: A review. Clin Orthop Relat Res 2002;395:23-32. |
|22.||Komath M, Varma HK. Fully injectable calcium phosphate cement - A promise to dentistry. Indian J Dent Res 2004;15:89-95. |
|23.||Serraj S, Michaïlesco P, Margerit J, Bernard B, Boudeville P. Study of a hydraulic calcium phosphate cement for dental applications. J Mater Sci Mater Med 2002;13:125-31. |
|24.||Chaung HM, Hong CH, Chiang CP, Lin SK, Kuo YS, Lan WH, et al. Comparison of calcium phosphate cement mixture and pure calcium hydroxide as direct pulp-capping agents. J Formos Med Assoc 1996;95:545-50. |
|25.||Yoshimine Y, Maeda K. Histologic evaluation of tetracalcium phosphate-based cement as a direct pulp-capping agent. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1995;79:351-8. |
|26.||Sena M, Yamashita Y, Nakano Y, Ohgaki M, Nakamura S, Yamashita K, et al. Octacalcium phosphate-based cement as a pulp-capping agent in rats. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;97:749-55. |
|27.||Zhang W, Walboomers XF, Jansen JA. The formation of tertiary dentin after pulp capping with a calcium phosphate cement, loaded with PLGA microparticles containing TGF-1. J Biomed Mater Res 2008;85A:439-44. |
|28.||Fernandez AC, Mohanty M, Varma HK, Komath M. Safety and efficacy of Chitra-CPC calcium phosphate cement as bone substitute. Curr Sci 2006;91:1678-86. |
|29.||Stanley HR. Criteria for standardizing and increasing credibility of direct pulp capping studies. Am J Dent 1998;11 Spec No:S17-34. |
|30.||Beaver HA, Kopel HM, Sabes WR. The effect of zinc oxide-eugenol cement on a formocresolized pulp. J Dent Child 1966;33:381-96. |
|31.||Myers DR, Pashley DH, Whitford GM, McKinney RV. Tissue changes induced by the absorption of formocresol from pulpotomy sites in dogs. Pediatr Dent 1983;5:6-8. |
|32.||Berger JE. Pulp tissue reaction to formocresol and zinc oxide-eugenol. ASDC J Dent Child 1965;32:13-28. |
|33.||Kennedy DB, el-Kafrawy AH, Mitchell DF, Roche JR. Formocresol pulpotomy in teeth of dogs with induced pulpal and periapical pathosis. ASDC J Dent Child 1973;40:208-12. |
|34.||El-Meligy O, Abdalla M, El-Baraway S, El-Tekya M, Dean JA. Histological evaluation of electrosurgery and formocresol pulpotomy techniques in primary teeth in dogs. J Clin Pediatr Dent 2001;26:81-5. |
|35.||Alliot-Licht B, Jean A, Gregoire M. Comparative effect of calcium hydroxide and hydroxyapatite on the cellular activity of human pulp fibroblasts in vitro. Arch Oral Biol 1994;39:481-9. |
|36.||Shayegan A, Petein M, Abbeele AV. Beta-tricalcium phosphate, white mineral trioxide aggregate, white Portland cement, ferric sulfate, and formocresol used as pulpotomy agents in primary pig teeth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105:536-42. |
|37.||Jean A, Kerebel B, Kerebel LM, Legeros RZ, Hamel H. Effects of various calcium phosphate biomaterials on reparative dentin bridge formation. J Endod 1988;14:83-7. |
|38.||Goldberg M, Smith AJ. Cells and extracellular matrices of dentin and pulp: a biological basis for repair and tissue engineering. Crit Rev Oral Biol Med 2004;15:13-27. |
|39.||Téclès O, Laurent P, Zygouritsas S, Burger AS, Camps J, Dejou J, et al. Activation of human dental pulp progenitor/stem cells in response to odontoblast injury. Arch Oral Biol 2005;50:103-8. |
|40.||Alliot-Licht B, Bluteau G, Magne D, Lopez-Cazaux S, Lieubeau B, Daculsi G, et al. Dexamethasone stimulates differentiation of odontoblast-like cells in human dental pulp cultures. Cell Tissue Res 2005;321:391-400. |
|41.||Lesot H, Lisi S, Peterkova R, Peterka M, Mitolo V, Ruch JV. Epigenetic signals during odontoblast differentiation. Adv Dent Res 2001;15:8-13. |
|42.||Yildirim S, Alacam A, Saritas K, Oygur T. In vivo effect of calcium phosphate biomaterials on dog dental pulp. Biotechnol Biotechnol Equip 2007;21:198-204. |
|43.||Fuks AB, Eidelman E, Cleaton-Jones P, Michaeli Y. Pulp response to ferric sulfate, diluted formocresol and IRM in pulpotomized primary baboon teeth. ASDC J Dent Child 1997;64:254-9. |
|44.||Røolling I, Lambjerg-Hansen H. Pulp condition of successfully formocresol-treated primary molars. Scand J Dent Res 1978;86:267-72. |
|45.||Schröder U. Effects of calcium hydroxide-containing pulp-capping agents on pulp cell migration, proliferation, and differentiation. J Dent Res 1985;64:541-8. |
|46.||Guelmann M, Fair J, Turner C, Courts FJ. The success of emergency pulpotomies in primary molars. Pediatr Dent 2002;24:217-20. |
|47.||Guelmann M, Fair J, Bimstein E. Permanent versus temporary restorations after emergency pulpotomies in primary molars. Pediatr Dent 2005;27:478-81. |
|48.||Mjör IA, Tronstad L. Experimentally induced pulpitis. Oral Surg Oral Med Oral Pathol 1972;34:102-8. |
Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Science and Technology, Trivandrum, Kerala
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]