VITAL PULPOTOMY IN PRIMARY TEETH WITH MINERAL TRIOXIDE AGGREGATE ( MTA )

Mortal pulpotomy is the most commonly used technique in Bulgaria for treatment of pulp chronic infections in primary teeth. Data from the special literature reveal another method for pulp treatment in primary teeth – vital pulpotomy associated with good adaptive healing response. During the past several years, special attention has been paid to Mineral Trioxide Aggregate -MTA as probable alternative of formocresol. According to the current trends in dental medicine about cessation of arsenic usage and limitation on formalin – containing medicaments usage, there will be a revision of commonly used method of mortal amputation, including application of arsenic, tricresolformalin, resorcine or resorcine –formalin solutions. The aims of this study are to aprobate and popularize the technique of vital pulpotomy in primary teeth with MTA. The study was carried out with children (the children’s age was 4 – 8 years) with primary molars approximately equally affected by a carious process which had reached the dental pulp and had to be treated. The total number of studied primary teeth was 33. The methodology is “one visit” and was performed following equal clinical protocol for all teeth. The pulp stump was covered with an MTA pasteAngelus (Solucoes Odontologicas, Londrina, Brazil), prepared by mixing MTA powder with sterile saline using 3:1 powder/saline ratio. Restoration of the teeth was performed with GIC. All treated teeth were follow-up clinically and radiographically during 6 months, at 6 and 12 month after vital pulpotomy. Results: The success rate of all pulpotomized teeth with MTA was 100 % after 6 months and shows statistically insignificant decrease to 90, 9% after 12 months (p > 0, 05). The number of teeth with unsuccessful treatment is 3 or 9, 1 %. Conclusion: Vital amputation with MTA is a reliable biological method for pulp treatment of primary teeth and could be recommended for the clinical practice.

Mineral trioxide aggregate (MTA) was developed and introduced in 1993 at the Loma Linda University, California, USA, as a root-end filling material and was approved by The US Food and Drug Administration for human teeth treatment application in 1998 (7,23,53,55,59).MTA is biocompatible material and its sealing ability is superior to amalgam or zinc oxyde eugenol (ZOE) (7, 10, 24,58,59,61).It was found that MTA has the ability to stimulate the release of cytokines from bone cells, which demonstrates the active assistance of MTA in hard tissue formation (7, 29,31,35,60).
In Bulgaria complications from dental caries in primary teeth have high prevalence.According to the current trends in dental medicine about cessation of arsenic usage and limitation on formalin -containing medicaments usage, there will be a revision of commonly used method of mortal amputation, including application of arsenic, tricresolformalin, resorcine or resorcine -formalin solutions.
The aims of this study are to aprobate and popularize the technique of vital pulpotomy in primary teeth with MTA.
To achieve the aims of this study, the following tasks have been set: 1.To review the dental literature and to present the newest studies and their results about the success and disadvantages of vital pulp therapy with MTA in primary teeth.
2. To perform vital pulpotomy with MTA on primary teeth with carious complications.
3. To test the clinical results on 6 and 12 months after MTA pulpotomy.

MATERIAL AND METHOD:
Realization of the first task requires electronicscreening using key words of the special literature published after 1993 for studies and articles in relation to characteristics and clinical applications of MTA in pediatric dental practice.
The study was carried out with children with primary molars approximately equally affected by a carious process which had reached the dental pulp and had to be treated.The total number of studied primary teeth was 33, but this number did not correspond to the number of examined children, because some of them had more than one tooth needing pulp treatment.The children's age was 4 -8 years, they were healthy, without signs of systematic diseases and with positive attitude toward dental treatment.Treatment plan in details, possible feeling of discomfort and treatment stages were explained to the parents and to the children.The parents gave their informed consent.Diagnostic and treatment protocols, as well as re-call observations were performed by two specialists in pediatric dentistry.
Selection criteria for the examined teeth were: 1.Primary teeth with deep carious lesion: no history of spontaneous or night pain, swelling, presence of fistula or tooth mobility 2. Primary teeth with vital pulp exposure as a result of carious process, with hemorrhage at the site of exposure 3.No clinical signs or evidence for total pulp inflammation (prolonged hemorrhage) or pulp degeneration (percussion sensitivity).
4. Absence of radiographic evidence for internal or external root resorption or radiolucency in furcation area.
5. No more than 1/3 physiological root resorption 6. Possibility for further tooth restoration

CLINICAL PROTOCOL
The methodology is "one visit" and was performed following this clinical protocol.Administration of local anesthesia for effective pain control.After removal of the carious tissues, the pulp chamber was accessed with bur N o 330, high speed handpiece and water spray.Following removal of the coronal pulp with an excavator or round bur, hemostasis was obtained using cotton pellets soaked in saline solution.The pulp stump was covered with an MTA paste-Angelus (Solucoes Odontologicas, Londrina, Brazil), prepared by mixing MTA powder with sterile saline using 3:1 powder/saline ratio (fig.1).The manufacturers recommend mixing 0, 33 g water with 1 g MTA to achieve optimal material mix.For optimal hardening of MTA manufacturers recommend placement of wet cotton pellets in cavum pulpae for a short period before application of MTA.Restoration of the teeth was performed with GIC.

Treatment approach philosophy
Vital pulpotomy in primary teeth is necessary to achieve adaptive biological response from the pulp-dentinal complex of treated tooth, to stabilize the affected tooth and to create favourable conditions until the time of its natural exfoliation.

Treatment follow-up
All treated teeth were follow-up clinically and radiographically during 6 months -at 6-th and 12-th month after vital pulpotomy.
The clinicians made their independent evaluations of the treated teeth using definite clinical criteria, and together As unsuccessful was referred treatment with one of the clinical or radiographic criteria described above.The data were recorded in patients' documentation and serve as a basis for evaluation at re-call visits.

RESULTS
The literary review about studies and results for success and disadvantages of vital pulp therapy with MTA in primary teeth is presented in Table 1.
The literary data about clinical evaluation of MTA demonstrate: • High success rate (clinically and radiographically) of MTA as pulp-capping agent in primary teeth pulpotomy.
• MTA could be a substitute for formocrelol as a pulpcapping agent on primary teeth • MTA doesn't lead to internal root resorption.
The literary data about histology evaluation of MTA usage demonstrate: • MTA shows no mutagenic or cytotoxic properties • MTA is biocompatible and suitable material for perforation healing, as it induces very slight inflammation, even if overextended in the perforation area • In vitro studies of human odontoblasts show that MTA stimulates synthesis of cytokines and interleukin products.
• MTA stimulates hard tissue formation -release calcium in form of calcium hydroxide.
• MTA stimulates formation of "dentinal bridge" and preserve the vitality of the remaining pulp tissue.
Available evidences suggest that formocresol, calcium hydroxide and MTA have comparable effectiveness The success rate of all pulpotomized teeth with MTA was 100 % after 6 months and shows statistically insignificant decrease to 90, 9% after 12 months (p > 0,05).(Diagr.1).The number of teeth with unsuccessful treatment is 3 or 9, 1 %.The authors associate the unsuccessful cases with compromise made with the clinical protocol, as well as including teeth with boundary criteria as indication to be included in the experiment, frequently -prolonged bleeding from root canal pulp tissues.

Diagram 1. → Results from clinical and radiographic follow-up.
We represent a successful clinical case of pulpotomy with MTA (fig.2.). in vital pulpotomy of primary teeth.
After 6 months 33 teeth were follow-up -100% of treated teeth.All of these teeth were assessed clinically and radiographically as successful -with no fistula, swelling or inflammation of the surrounding gingival tissue, pathologic mobility, tenderness in percussion, as well as external and internal root resorption or widening of periodontal ligament space (Table 2).
After 12 months clinical and radiographic evaluation were performed on 30 teeth.The other 3 teeth were assumed as teeth with unsuccessful treatment and postoperative healing period, because of: 1 tooth with pain, 2 teeth with high degree of mobility and presence of inflammation in gingival tissues (Table 2).One of these teeth was extracted and the others were treated with resorcin -formalin method.Clinical and radiographic evaluation for the other 30 teeth shows successful healing process in pulp tissue (table 3).
We have chosen a pulpotomy with MTA, because MTA has not toxic side effects -systematic or local, this pulpotomy has shorter clinical protocol and excellent therapeutic effect (according to literary review) (33,45,51,56).
The commercial price of 1 gr.MTA-Angelus (Brazil) is 99 leva, this amount MTA is enough to perform 15 pulpotomies and this means that the mean price is 6 leva per tooth.
To achieve an optimal solidity and compressive strength, some authors suggest waiting for 24 hours before definitive restoration of the tooth (16,59,64).We preferred for the definitive restoration the conventional GIC, because it could be placed on partially hardened MTA in one-visit procedure (according to literary data) and this way allows undisturbed hardening of MTA below (8, 42,56,62).
The results of this study show success rate of 90, 9 % for one year follow-up period.

CONCLUSION
• The current study shows high success rate of pulp amputation with MTA for the period of observation.
• Definite conclusions could not be done, because of the small number examined teeth, as well as relatively short follow -up period.
• Vital amputation with MTA requires close stick to the clinical protocol.
• Vital amputation with MTA is a reliable biological method for pulp treatment of primary teeth and could be recommended for the clinical practice.

Table 1 .
Pulpotomy in primary teeth -studies of different authors

Table 2 .
Results from the clinical evaluation