Tanta Dental Journal

: 2017  |  Volume : 14  |  Issue : 1  |  Page : 40--44

Histological evaluation of the effect of trichloroacetic acid and mineral trioxide aggregate on human teeth pulp

Ibrahim B Farouk1, Galal A Nasr2, Kamal A Eldalgmony3,  
1 Department of Pedodontics and Oral Health, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt
2 Department of Oral Biology, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt
3 Department of Oral Pathology, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt

Correspondence Address:
Galal A Nasr
Department of Pedodontics and Oral Health, Faculty of Dental Medicine, Al-Azhar University, Cairo


Objective: The objective of this study was to compare between the effects of two medicaments [trichloroacetic acid (TCA) and mineral trioxide aggregate (MTA)] on the remaining pulp tissue of the young permanent teeth after pulpotomy. Materials and methods: The present study comprised 30 premolars. Pulpotomy procedure was performed. The radicular pulp was capped with MTA in premolar in one side and with TCA in those of the other side. Premolars were reviewed after successive periods (1 week, 1, and 3 months). Teeth were extracted after examination periods. Sections was then stained by standard hematoxylin and eosin stain. Results and conclusion: Bridge formation was seen in TCA group after 3 months which is a desirable finding in pulpotomy procedures, whereas MTA is superior to TCA in treating pulps in human teeth.

How to cite this article:
Farouk IB, Nasr GA, Eldalgmony KA. Histological evaluation of the effect of trichloroacetic acid and mineral trioxide aggregate on human teeth pulp.Tanta Dent J 2017;14:40-44

How to cite this URL:
Farouk IB, Nasr GA, Eldalgmony KA. Histological evaluation of the effect of trichloroacetic acid and mineral trioxide aggregate on human teeth pulp. Tanta Dent J [serial online] 2017 [cited 2021 Oct 19 ];14:40-44
Available from: http://www.tmj.eg.net/text.asp?2017/14/1/40/202060

Full Text


Dental caries is among the most prevalent chronic diseases worldwide [1]. It is a dynamic process since periods of demineralization alternate with periods of remineralization through the action of fluoride, calcium, and phosphorous contained in oral fluids [2]. Carious lesions involving the pulp, if not treated will lead to pulpal necrosis and often involvement of the periradicular tissues, with pain and discomfort for the patient [3]. Among the methods for preservation of a cariously exposed pulp, vital pulp therapy has yielded a markedly high success rate in young permanent teeth [4].

Apexogenesis refers to a vital pulp therapy procedure performed to encourage development and formation of the root end. Apexogenesis aims to preserve pulp vitality which is essential for root formation and apical closure [5]. Many researchers prefer the pulpotomy techniques than the direct pulp capping after accidental exposure during cavity preparation or after exposures following excavation of deep caries [6]. Several capping materials have been suggested as pulpotomy agents including calcium hydroxide, dentine bonding agents, bioactive glass, white and gray mineral trioxide aggregate (MTA) [7]. Numerous investigations have been performed to compare these materials as pulp-capping and pulpotomy agents in animals and humans [8].

Trichloroacetic acid (TCA) was reported to have been first synthesized in 1840 by chlorination of acetic acid in sunlight. The main therapeutic application of TCA in dentistry has been removal of excess gingival tissue before restorative procedures [9]. Historically, other dental applications have included the management of sepsis following extraction: reduction of dentine sensitivity; removal of calculus; treatment of necrotizing gingivitis; treatment of pericoronal infection; and as a sclerosing agent for jaw cysts to avoid apicectomy [10]. Clinical and histological research of TCA effect on the pulp of dog's teeth; distinguished outcomes have been reported that encouraged the researcher to evaluate its clinical effect on human dental pulp [11]. The objective of this study was to compare the histological effects of MTA and TCA on the pulp tissue of young permanent teeth.

 Materials and Methods

The teeth involved in this study were limited to first premolars, which required exodontia in the course of orthodontic treatment. All patients are informed about the purpose and steps of this research and written consents are signed according to the ethics committee of Faculty of Dental Medicine, Al-Azhar University. Patients were selected according to the following criteria:

They should have contra lateral pairs of premolarsThey should have no medical problems.

A total of 30 premolars were included in the current study, obtained from 15 patients, 18 were girls and 12 were boys. The patient's ages were between 13 and 24 years. Pulpotomy procedure was performed after giving anaesthetize to the selected teeth and isolated with rubber dam. Coronal access was obtained with a sterile tungsten carbide bur in a high speed hand-piece under constant water spray. The pulp was removed from the pulp chamber using a sterile sharp spoon excavator until the orifices of the root canals were reached. Next, bleeding was controlled with pressure applied with a sterile cotton pellet soaked in sterile saline.

The teeth were divided into two group according the capping material used, MTA was used in group A (15 premolars) while TCA was used in group B (other 15 premolars). The radicular pulp was capped with MTA in premolar in one side and with TCA in those of the other side. A sterile cotton pellet was dipped into a 90% aqueous solution of TCA. After excess solution on the cotton pellet was removed by dampening on sterile gauze, the cotton pellet was carefully applied with light pressure on to the pulp stump for 30 s. If some bleeding was seen after 30 s, this procedure was repeated for another 30 s. After the completion of this procedure, the cavities were sealed permanently with zinc oxide eugenol and restored with amalgam.

Premolars were reviewed after successive periods (1 week, 1, and 3 months). At each review appointment, the presence or absence of the following signs and symptoms was assessed clinically: pain, tenderness to percussion, gingival inflammation, draining sinus, and mobility. Premolars were extracted at successive intervals. Teeth were extracted and fixed in 10% neutral buffered formalin solution for 48 h. After that, decalcification of the teeth was performed by immersion in formic acid–sodium citrate for 30 days. The all specimens were checked and the decalcified solution was changed daily.

After decalcification, all specimens were routinely processed with hematoxylin and eosin stain. The all sections were examined with light microscope under low and high magnification, by two observers, every sample was evaluated for formation the dentin bridge according to presence or absence of bridge beneath the pulpotomy dressing. All the obtained data were statistically analyzed using SPSS program, version 22 (SPSS Inc., Chicago, Illinois, USA). The paired Student's t-test was used to compare between groups A and B at a 95% level of confidence.

 Histological Results

Microscopic examination of histological sections, using hematoxylin and eosin stain, revealed alterations in the pulpal tissue elements of both groups A (MTA) and B (TCA) throughout the different experimental intervals.

Group A (mineral trioxide aggregate) at 1 week

The initial microscopic observation at the coronal part, revealed: remnants of the capped material. Irregularity of predentin and alteration throughout the pulp tissue elements in different parts of the pulp was seen. The encountered degeneration of both odontoblasts and pulpal connective tissue ([Figure 1]a). At the middle part, crowding of the odontoblasts at one side, condensation and pulpal connective tissue, dilated blood vessels containing red blood cells with thrombus formation and inflammatory cell infiltrates were seen without area of necrosis, the bridge formation were seen in two cases ([Figure 1]b).{Figure 1}

Group A (mineral trioxide aggregate) at 1 month

Histological sections at the coronal part, showed: areas of hyalinization, remnants of the capped material the middle part revealed degeneration of the odontoblastic cell layer which crowded at one side ([Figure 2]a). The pulpal connective tissue showing areas of necrosis, the bridge formation was seen in three cases ([Figure 2]b).{Figure 2}

Group A (mineral trioxide aggregate) at 3 months

Histological sections at the coronal part, revealed remnants of the capped material, formation of new calcified tissue (dentin bridge) superimposed with inflammatory cell infiltration which bordering the pulpal connective tissue proper ([Figure 3]a) and narrowing the middle part, The bridge formation was seen in five of cases ([Figure 3]b).{Figure 3}

Group B (trichloroacetic acid) at 1 week

Histological sections at the coronal part, revealed condensation of the connective tissue fibers at the superficial part beneath the capped material, regular thickness of predentin and degeneration of both odontoblasts and pulpal connective tissue fibers. The latter showed different patterns with variable thickness and irregularities. An extensive pulpal connective tissue edema with inflammatory cell infiltrates and dilated blood vessels containing thrombus formation were, also, seen ([Figure 4]a). The middle part revealed duplication and irregularity of the odontoblastic layer. In addition, pulpal connective tissue with hyalinization, edema, and inflammatory cell infiltrates were seen ([Figure 4]b). No dentin bridge was observed in all cases.{Figure 4}

Group B (trichloroacetic acid) at 1 month

Histological sections at the coronal part revealed remnants of the capped material, hyalinization of pulpal connective tissue fibers and inflammatory cell infiltrates. Pulpal connective tissue degeneration with intercellular edema, inflammatory cell infiltrates, and dilated blood vessels with thrombus formation were seen ([Figure 5]a). The middle part showed hyperplasia of the odontoblasts, inflammatory cell infiltrates, and pulpal connective tissue fibers with variable thickness and degenerative changes ([Figure 5]b). The bridge formation was seen in one cases.{Figure 5}

Group B (trichloroacetic acid) at 3 months

Histological sections at the coronal part, revealed calcified tissue (dentin bridge) beneath the capped material. Pulpal connective tissue degeneration composed of dystrophic calcification was seen. Pulpal connective tissue showed, also, extensive inflammatory cell infiltrates and necrosis ([Figure 6]a). The middle part revealed degeneration of the odontoblasts and pulpal connective tissue. The latter showed inflammatory cell infiltrates and edema fluid. Hyperplasia of the odontoblasts in addition to edema and hyalinization of connective tissue fibers were seen ([Figure 6]b), the bridge formation was seen in two cases.{Figure 6}

Statistical analysis

There was a statistically significant difference in dentin bridge formation after 1 week, 1, and 3 months between groups A and B after pulpotomy (P ≤ 0.05) ([Table 1] and [Figure 7]).{Table 1}{Figure 7}


In this study, pulpotomy was performed for human premolar teeth to histological evaluate the response of the dental pulp to two different pulpotomy dressings (TCA and MTA) over three different pulpotomy durations. The pulpotomy procedure for primary and young permanent teeth is indicated when the infected coronal tissue can be amputated and the remaining radicular tissue is judged to be vital or affected but still vital, by clinical and radiographic criteria. The main objective of this treatment modality today is to maintain the vitality of the majority of the radicular pulp [12].

MTA has been proposed as a potential medicament for pulpotomy procedures. MTA was found to maintain pulp integrity after pulpotomy in animal studies and to have adentinogenic effect on the pulp expressed by dentine bridge formation where it touches the pulp tissue [13],[14]. In the present study, MTA was shown to be a suitable material for dentine bridge formation. No necrosis was observed, no degree of inflammation was observed in the samples after 3 months, when MTA was used as the pulpotomy dressing. Asgary et al. [15] reported a nondentinal bridge formation after 2-week pulpotomy duration when MTA was used as a pulpotomy dressing for pulpotomised teeth of dogs. Agamy et al. [16] compared MTA and formacresol in pulpotomised primary teeth. Both MTA and formacresol induced a dentine bridge formation after 6 months. The MTA induced a thick bridge while formacresol induced a thin calcified dentine. Chacko and Kurikose [17] reported dentine bridge formation after 4 and 8 weeks when MTA was used as a pulpotomy dressing.

The dentine bridge formation was more homogenous and continuous with the original dentine when compared with pulps capped with calcium hydroxide [17]. Faraco Junior and Holland [18] reported bridge formation after 8 weeks, and Salako et al. [13] reported bridge formation after 2 and 4 weeks when MTA was used as pulpotomy dressing. Khayat et al. [19] also reported bridge formation after 30 days when dogs' teeth were pulpotomised with MTA. In the histological study of Karami [11], concluded that MTA is superior to formacresol and TCA in treating pulps in dogs. These reports all support the findings from the current study. In the present study, when MTA was used as a pulpotomy dressing, reappearance of odontoblasts was seen 1, 4 weeks, and 3 months pulpotomy durations respectively.

In this study, TCA is introduced as a new pulpotomy agent in human teeth. The use of TCA, as an adjunct for treatment of aggressive external cervical root resorption, was introduced by Heithersay [20]. He recommends applying a 90% aqueous solution of TCA to the resorptive defect to eliminate the resorbing tissue and establish around base for tooth restoration. TCA is a chemical escharotics agent that has been used in medicine and dentistry for more than a century. It produces a defined zone of coagulation necrosis when applied to soft tissues [10]. The chemocauterization effect of TCA is used in this study to cauterize the pulp stump on the orifice of the teeth roots after the removal of the pulp from the pulp chamber. When TCA was used in this study as a pulpotomy dressing, no cases of necrosis were reported in any of the pulpotomy durations.

No clinical or radiographic signs to show pulp necrosis was seen either. Bridge formation was evident from 1 month after pulpotomy in TCA samples. At 8-week pulpotomy duration, cases showed bridge formation and all were irregular. Reappearance of odontoblasts was seen after 3 months, the dentine bridge formation revealed reappearance of odontoblasts. The presence of inflammatory cells was seen until the end of the experimental duration for all groups, which indicates that healing and bridge formation can be seen simultaneously with inflammatory response.


MTA is superior to TCA in treating pulps in human teeth. It is logical to believe that MTA is a more biologically acceptable material to the pulp tissue than is TCA. However, bridge formation was seen in TCA cases after 1 month which is desirable finding in pulpotomy procedures. TCA is a material with a chemocauterization effect used in medicine and dentistry. It is relatively inexpensive and available compared with MTA. No carcinogenic or mutagenic effect regarding this material has been reported. It is the first time TCA has been recommended as a pulpotomy agent. TCA can be recommended as a pulpotomy medicament in clinical practice.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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