Clinical and Radiographic Evaluation of Vital Pulpotomy in Primary Molar using Antioxidant Mix as a Novel Pulpotomy Medication versus Formcresol: A Randomized Clinical Trial.

Introduction

Irreversible damage to the dental pulp due to dental caries is one of the major causes that lead to premature loss of a primary tooth. The most important goal in pediatric dentistry is to preserve primary teeth until the time of eruption of their permanent successors. ¹

The most commonly used technique to preserve cariously involved primary molars that would be otherwise extracted is pulpotomy. This technique involves amputation of the coronal pulp tissue with preservation of the vitality and health of radicular pulp tissue by covering it with a suitable medicament.²

In pulpotomy, many materials were used over the years but the ideal material should meet certain criteria, such as it should be bactericidal, harmless to the pulpal tissue and surrounding structures, promote healing of the radicular pulp, does not interfere with normal physiological root resorption, and preserve the radicular pulp without any clinical or radiographic symptoms. ³

In 1930, Formocresol (FC) was first introduced by sweet and for many years it was the most commonly used material in pulpotomy.⁴FC is both a bactericidal and a devitalizing agent. It kills off and converts bacteria and pulp tissue into inert compounds. Despite being recommended for use by AAPD ⁵ and still successfully used in developing countries, concerns have been raised about FC regarding its mutagenicity, carcinogenicity, its local toxicity, its potential damage to a permanent successor, systemic toxicity and finally its antigenicity. So, a search for an ideal alternative agent that is more biocompatible than FC is mandatory. ^{6, 7}

Nowadays, the introduction of new Bio-inductive materials resulted in the shift of the concept of preservation of radicular pulp tissue to regeneration. ⁸Restoration of the anatomical continuity of damaged tissue and disturbed functional status of the radicular pulp tissue require appropriate method of wound healing which includes   well-organized, biochemical and cellular events, leading to the growth and regeneration of injured radicular tissue in a special manner. ⁹

Antioxidants counter the excess proteases and reactive oxygen species (ROS) often formed by neutrophil accumulation in the wounded area and protect protease inhibitors from oxidative damage. These excess ROS kills fibroblast and other cells, also antioxidants have both anti- inflammatory and anticarcinogenic effects ¹⁰, Thus this study aims to evaluate the clinical and radiographic success rate of antioxidant mix versus FC as a pulpotomy agent in primary molars.

Subjects and Methods:

Thirty- five (35) patients with fifty-two (52) mandibular primary molars indicated for vital pulp therapy were recruited to participate in this study.

PICO:

P: mandibular primary molars.

I: pulpotomy using Anti-oxidant mix.

C: pulpotomy using Formocresol.

O: clinical success rate.

Research question: Is pulpotomy procedure in primary molars using Anti-oxidant mix more clinically successful than Formocresol?

Ethics approval:

The research    protocol    was approved   by   Research   Ethics Committee, Faculty of Dentistry, Cairo University with the reference code (4 5 2015).

Study design:

The study is a randomized clinical trial (RCT) where 2 arm parallel groups with a 1:1 allocation ratio were compared. The child participants and the legal guardian of each participating child and the statistician were blinded. Blinding of the investigators was not feasible due to the apparent physical characteristics of the used materials both clinically and radiographically (Antioxidant mix is radiolucent).

Sample size estimation:

The sample size was estimated using power and sample size calculations program (Sealed Envelope, London, UK).

Calculation was based on the formula:

n = f (α/2, β) × [p1 × (100 − p1) + p2 × (100 − p2)] / (p2 − p1)2

Where p1 and p2 are the percent 'clinical success' in the control and experimental group respectively, and f (α, β) = [Φ-1(α) + Φ-1(β)]2 Φ-1 is the cumulative distribution function of a standardized normal deviate.  

Adjustment for cross-overs based on formula: nadj = n × 10,000 / (100 - c1 - c2)2 where c1 and c2 are the percent cross-over in the control and experimental group

Since no numerical data could be taken from previous studies a preliminary estimation of research size was designated to 52 molars ( including a dropout rate of 20% ) , which were required to have an 80% chance of detecting, as significant at the 5% level, an increase in the primary outcome measure from 67% clinical success rate in the control group according to Sabbarini et al.,2008 work``Comparison of Enamel Matrix Derivative Versus Formocresol as Pulpotomy Agents in the Primary Dentition``¹¹  and to 97% clinical success rate  in the experimental group according to Reddy et al.,2014  work `` Antioxidant mix: A novel pulpotomy medicament: A scanning electron microscopy evaluation``. ¹²

Study setting:

The study was conducted at Pediatric Dentistry and Dental Public Health Department, Faculty of Dentistry,Cairo University, Egypt.

Trial Registration:

The study was registered by the main investigator with clinicaltrials.gov under the title: `` Clinical and Radiographic Evaluation of Vital Pulpotomy in Primary Molar Using Antioxidant Mix as A Novel Pulotomy Medication Versus Formcresol: A Randomized Clinical Trial ``, with an identifier: PACTR201711002568284.

Subjects selection:

Fifty-two (52) mandibular primary molars in thirty-five (35) children ranging in age from 4 to 8 years were recruited to participate in this study. Children were selected independent of their gender from the outpatient clinic of the Pediatric Dentistry and Dental Public Health Department, Faculty of Dentistry, Cairo University.

Eligibility criteria:

The eligibility criteria were set according to the guidelines of AAPD, 2015 .⁵

Inclusion criteria

Mandibular primary molars with no spontaneous or provoked pain.

Primary molars with at least two-thirds of the root length were still present.

Primary molars with no sign of internal or other kinds of root or bone resorption.

Exclusion criteria

Patients with systemic diseases (congenital or rheumatic heart disease, hepatitis, nephritis, tumor, cyclic neutropenia, leukemia, and children on long term corticosteroid therapy).

Un-cooperative patients.

Un-restorable primary molars (Grossly broken-down primary molars that have decay extending way under the gingiva and tooth with root caries).

Randomization & allocation concealment:

Simple randomization was done, to allocate the molars, using computer sequence generation (www.random.org)  by the third investigator with 1:1 allocation ratio into two groups (n=26) based on the dressing materials. group (1) designated for Antioxidant-mix and group (2) designated for FC as pulp medicaments. Allocation concealment was done using opaque envelopes.

Sequence generation:

Sequence generation was done for the molars number (1 to 52; 26 numbers in each group) by the third investigator using computer sequence generation (www.random.org).

Allocation concealment mechanism:

Each of the 52 papers numbered from 1 to 52, was individually packed by the third investigator in an opaque envelope after folding each paper eight folds. Each patient was asked to pick an envelope, after their enrollment in the study and before the beginning of treatment. The numbers in the envelopes determined the group assigned for each molar.

Informed Consent:

The procedure, their benefits, and risks were fully explained to the parents of the participants, and approval was taken by the main investigator through written informed consent.

Intraoperative procedure:

All intraoperative procedures were performed by the main investigator. Each tooth was locally anesthetized using topical anesthesia (20 % benzocaine gel, Deepak, Miami, USA) followed by, nerve block injection using Articaine HCI  4% with 1:100,000 epinephrine (Septanest, Saint-Maurdes-Fosses, France), then the tooth was isolated using a rubber dam.

Dental caries was removed with a large slow-speed round bur. Then access to the pulp chamber was obtained with no. 330 carbide bur, followed by amputation of the coronal pulp with a sharp spoon excavator. Stasis at the orifice of the radicular pulp was achieved with a moist cotton pellet placed on orifices under pressure for three min. If hemorrhage persisted, pulpectomy was performed and the tooth was eliminated from the study.

After stasis, in group (1) standard consistency of freshly prepared Antioxidant- mix (Pfizer Canada Inc, Montreal, Canada) was introduced in the pulp chamber using  dental spatula and condensed over the orifice with the aid of a suitable size condenser over a moist cotton pellet followed by a layer of reinforced Zinc Oxide Eugenol (ZOE) (Prevest Denpro limited, Digiana, India),  while in group (2) a sterile cotton pellet lightly moistened with a 1:5 dilution of  Buckley's FC (Prevest Denpro limited, Digiana, India) was  placed against the pulpal stumps for three- five minutes, then removed. A layer of reinforced ZOE was condensed against the orifices using a suitable size condenser over a moist cotton pellet.

In both groups, molars were finally restored with stainless steel crown (3M, ESPE, USA), which was cemented by glass ionomer cement (Ningbo Gaoju Imp. & Exp. Co., Ltd, Zhejiang, China).  Finally, postoperative periapical radiographs of the treated teeth were taken using size two periapical film (Kodak, Carestream Health, Inc., NY, USA) and considered as a baseline, Fig (1, 2).

Strategies to improve adherence to the intervention

Face to face session with the patients’ parents by the main investigator was held to stress on the importance of follow up. The main investigator ensured that the follow-up appointments are obligatory to assess the outcome of initial treatment and to discuss other treatment options if this treatment failed to meet expected goals.

Follow-up protocol & Assessments of the outcomes:

All treated molars were followed up by the second and third investigators at three, six and nine months for clinical and radiographic evaluation. Blinding was not feasible as Antioxidant-mix appears radiolucent in the radiographs.

The intraexaminer consistency was confirmed, between the two examiners, through repeated clinical examinations and radiographic interpretation for 10 molars. Kappa test showed that the intraexaminer and interexaminer consistencies were 100 % and 99%, respectively.

Molars were judged as clinically successful if they met the following criteria: Absence of sensitivity, pain, tenderness to percussion, abscess, fistula, or tooth mobility. Radiographic failure was defined according to the radiographic failure score according to Memarpour et al., 2016. ¹³

Criteria for discontinuing or modifying intervention:

In case of the presence of adverse clinical signs (pain, abscess, etc…) the case was managed by pulpectomy or extraction and considered as failure.

Statistical analysis:

All data were tabulated and refereed to the statistician blindly.  Statistical analysis was performed using SPSS statistical version 19 (Statistics Statistical Procedures Companion, Chicago, IL, USA. Chi-square test was used for comparison of all binary outcome data at different times points and T-test was used to compare the mean age in both groups. The Significance level was set at p <0.05.

Results

The mean age of anti-oxidant group and FC group were 6.08 ±1.1 and 5.9±1.35 respectively. The antioxidant group included 14 males (53.8%) and 12 females (46.2%), whereas FC group included 50% males & 50% females. The Antioxidant group consisted of 15 D (57.7%) & 11 E (42.3%), whereas FC group consisted of 11 D (42.3%) & 15 E (57.7%), with no statistically significant difference between the two groups regarding age, sex and type of treated molar. One case dropped out from group (1) & another one from group (2), Table (1-3), Fig. 1.

Results of clinical findings at different follow-up periods showed no statistically significant difference between the two groups in terms of