PRE-OPERATIVE PAIN: A NOVEL INDICATOR TO GOVERN THE CHOICE OF PULPOTOMY AGENT IN PRIMARY TEETH. A RETROSPECTIVE STUDY

Headnote

Abstract

Pulpotomy is a vital pulp procedure performed in primary teeth. The aim of the study is to evaluate whether the presence of pre-operative pain affects the success of pulpotomy in primary teeth and whether either Formocresol (FC) or Mineral Trioxide Aggregate (MTA) performs better in patients with positive history of pain. 120 cases were selected for the study, 60 with and 60 without history of pre-operative pain associated with the pulpotomized tooth, further sub-divided into FC and MTA groups, 30 cases each. The clinical and radiographic success of pulpotomized teeth with positive history of pain was 70% and 53.3%, respectively. Among these, 60% of the teeth treated with FC and 80% of those treated with MTA were clinically successful, while radiographic success was 33.33% and 73.3%, respectively. The results suggest that the presence of pre-operative pain negatively affects the success of pulpotomy.

Keywords: pulpotomy, formocresol, mineral trioxide aggregate, primary teeth.

1.INTRODUCTION

Pulpotomy is the most frequently used vital pulp therapy procedure in carious primary teeth, where caries removal results in pulpal exposure [1]. It involves amputation of the coronal pulp and placement of a medicament over the radicular pulp stumps in order to promote healing. It is based on the rationale that the healthy radicular pulp is capable of healing after removal of the affected coronal pulp tissue.

The ideal pulpotomy agent should be bactericidal, biocompatible, promote healing of the remaining pulp, not interfere with the normal physiologic root resorption and preserve radicular pulp health both clinically and radiographically [2].

Formocresol (FC) was the first pulpotomy agent used in primary teeth in 1930 [3]. FC contains formaldehyde, a known carcinogen [4], which has raised concerns regarding its use in dentistry. Additionally, at histological level, FC does not produce a favorable pulpal response [5]. It causes chronic inflammation within the pulp, which may initiate root resorption, which is commonly associated with teeth treated with FC.

In 1995, Torabinejad introduced the Mineral Trioxide Aggregate (MTA). Its excellent biocompatibility, high pH, sealing ability and high compressive strength makes it an ideal choice as a pulpotomy agent [6]. It stimulates cytokines production and induces hard tissue barrier formation, by virtue of its dentinogenic and antimicrobial properties [7]. MTA has the ability to heal the tissue and cause regeneration, thus revolutizing the modern endodontic approach. Based on recent clinical studies, MTA appears to be the new gold standard for pulpcapping and pulpotomy procedures [8].

Management of deep carious lesions poses a challenge to the pediatric dentist. Diagnosis of pulp inflammation is the key to the success of pulp therapy, as the degree of the inflammation determines the repair and regeneration capacity of the pulp-dentine complex [9]. Inflammation is the response of the pulp to eliminate pathogens. In order to make an accurate diagnosis, patient's history and clinical signs and symptoms must be correlated [10]. There are five main parameters known to aid in diagnosis, if a patient presents with complain of pain; localization, commencement, intensity, provocation and duration [11]. The history of pain is an important diagnostic tool to assess the reversible and irreversible inflammation of the pulp affected with transient, stimulated pain, associated with reversible pulpitis and intense, lingering pain of spontaneous origin, associated with irreversible pulpitis [12]. The American Academy of Pediatric Dentistry recommends the use of both FC and MTA as pulpotomy agents and advocates the use of medicaments based on individual preferences [13]. The routine use of MTA, however, has been limited due to its high cost [14]. The current study aims at evaluating whether the presence of pre-operative pain affects the success of pulpotomy and whether either FC or MTA performs better in patients with positive history of pain. Both clinical and radiographic parameters were evaluated at one year follow-up. This is a variable which has never been accounted for in the studies on pulpotomy in primary teeth.

2.MATERIALS AND METHODS

A cross-sectional, observational study was conducted in Children Hospital, Pakistan Institute of Medical Sciences (PIMS), Islamabad, Pakistan, after getting institutional ethical permission (ref no SOD/ERB/2021/117). Data was collected retrospectively from the patient records of the Department of Pediatric Dentistry. Records of children aged 4-8 years, with no significant medical history, who had single-visit pulpotomy of the primary molars with either FC or MTA under rubber dam isolation, were included. Cases with complete pre-operative and one-year follow-up clinical and radiographic records were selected, while those with incomplete records and poor quality radiographs were excluded. Sample size was calculated to be 29, with 95% confidence level and 5% margin of error, taking the success of formocresol pulpotomy as 98.1% [15], so that a sample size of 30 cases for each group was considered. 120 cases were included, 60 with positive history of pre-operative pain and 60 without any history of pre-operative pain. They were further divided into two subgroups according to the pulpotomy agent used, i.e. either formocresol or MTA. Quota sampling technique was used to recruit 30 cases in all four subgroups. Figure 1 plots the flow chart of the cases included in the study. A total of 945 records of patients from June 2018 to August 2021 were evaluated and cases which met the inclusion and exclusion criteria were selected.

Pre-operative and one-year follow-up, clinical and radiographic findings for each selected tooth were noted and analyzed. Both clinical and radiographic outcomes were determined independently. The teeth were recorded as clinically successful if they were asymptomatic at one-year follow-up, i.e. having no signs and symptoms such as history of spontaneous or nocturnal pain, tenderness on percussion or palpation, abscess formation, swelling/ fistula and/or mobility. If any of these was present, the tooth was recorded as failure. The follow-up radiographs were evaluated for external or internal root resorption, periapical or furcation radiolucency and periodontal ligament (PDL) widening. If any of this element was present, the tooth was recorded as failure.

Data was analyzed using Statistical Package for Social Sciences (SPSS version 23). Chi-square test was applied to compare the effect of pre-op pain on the clinical and radiographic success. Uni-variant analysis was done to compare the clinical and radiographic outcomes of both agents in the respective groups, a p-value <0.05 being considered significant.

3.RESULTS

The age of the patients included in the study was 4-8 years, with a mean of 5,9 years (SD+1,18), The overall success rate of the pulpotomized teeth at the end of one year was 78,3% clinically and 65% radiographically,

The results showed a positive association between pre-operative (pre-op) pain and clinical and radiographic success at the end of 12 months, The clinical success rate of pulpotomy in teeth without pre-op pain was 86,7% (n=52), and 70% (n=42) in those with positive history of pre-op pain with a p-value of 0,117, which is statistically not significant. The radiographic success of the teeth without pre-op pain was 76,7% (n=46), and 53,3% (n=32) in teeth with positive history of pain, The p-value was calculated to be 0,058, which is marginally significant. The results are summarized in Table 1,

In patients with pre-op pain, the FC treated teeth showed 60% (n=18/30) success, while MTA treated teeth showed 80% success (n=24/30), The p-value was calculated to be 0,232, which is not statistically significant.

The radiographic success rate was 33,3% (n=10/30) and 73,3% (n=22/30) for FC and MTA, respectively, in patients with pre-op pain, The p-value calculated was 0,028, which is statistically significant.

Root resorption was associated with 20% (n=12/60) teeth without pre-op pain, being observed in 36,7% (n=22/ 60) teeth with positive history of pre-op pain, It was noted that 53,3% (n=16/30) of the teeth with pre-op pain treated with FC showed root resorption, but in only 20% (n=6/30) of the teeth treated with MTA, The calculated p-value was 0,058, which was marginally statistically significant.

4.DISCUSSION

One of the main goals in pediatric dentistry is to retain the primary teeth in the mouth until they exfoliate in their due time [1], Over the years, researchers have tried to search for an ideal pulpotomy agent capable of healing residual pulp [16], MTA has revolutionized modern endodontics with its regenerative properties, Multiple clinical trials have proven its success over FC, which was considered a gold-standard agent for pulpotomy in primary molars [17], meeting all requirements of an ideal pulpotomy agent,

Among the many factors reported in literature regarding the failure of pulpotomy in primary teeth, the main are undiagnosed inflammation of the radicular pulp, lack of isolation and incomplete removal of the coronal pulp [18], One of the most significant factors leading to failure is the incorrect diagnosis of inflamed radicular pulp [19]. The probable cause of internal resorption is the misdiagnosis of the existing inflammation in the pulpal tissue present before the procedure, rather than the exposure to the pulpotomy medicament. This inflammation continues, resulting in failure of the pulpotomy.

The current study aimed at finding whether pre-operative pain could serve as a clinical indicator for the choice of the pulpotomy agent. As shown in Table 1, irrespective of the pulpotomy agent used, the clinical success of teeth with positive history of pain was of 70%, while those without any history of pain showed a success of 86.7%. Similarly, the radiographic success of teeth with history of pain was 53.3%, while teeth without no pain showed 76.6% success. Although statistically insignificant, this shows that the presence of pain adversely affects the outcome of pulpotomy. Pain is a cardinal sign of inflammation [20]. As a thorough history of pain depends on the subjective findings reported by the patient and/or parents, they might not recall or report the precise history of pain itself. An accurate history of pain is imperative to differentiate reversible and irreversible type of pulpitis [12], while misreporting may result in an erroneous diagnosis of the clinician. It is proposed that a sub-clinical inflammation might be present in the radicular pulp of the teeth with positive history of pre-operative pain, which may progress and result in failure of pulpotomy. This is the possible reason why teeth with history of pre-op pain performed poorly both clinically and radiographically, comparatively with those showing with no pain.

The results of the present study demonstrate that the success rate of MTA was higher than that of FC, both clinically and radiographically, which agrees with the current literature [21]. However, the use of MTA in primary teeth has been limited due to its high cost [14].

Exploring the association of the pulpotomy agent used with the presence of pre-operative pain, it was observed that MTA performed better than FC in symptomatic teeth. Pulp has the innate potential to repair [22]. Cho and colleagues [23], while studying the prognostic factors of pulp therapy, stated that the outcome depends on the degree of pulp inflammation - so, the choice of pulp capping material holds utmost importance. MTA stimulates reparative dentinogenesis by recruiting the cytokines and growth-factors which mediate repair of the pulpdentine complex [24]. Extrapolating these evidences, MTA suppresses any residual inflammation and promotes healing of the radicular pulpal tissue. As formocresol lacks these properties, the sub-clinical inflammation, which may be present in symptomatic teeth, progresses and results in failure of pulpotomy. In the teeth with no history of pain, FC gives comparable results to MTA, as shown in Table 1.

Root resorption is a common cause of failure in pulpotomized teeth [1]. More root resorption was associated with teeth with positive history of pre-operative pain; among these teeth, MTA treated teeth showed better success. This observation further supports the hypothesis that MTA performs better in symptomatic teeth.

The results of our study show that the presence of pre-operative pain could serve as a clinical indicator to predict pulpal tissue health, thus warranting the use of a bio-inductive agent, such as MTA, which has the potential to combat any residual inflammation, if present. In the light of the findings of this study, the higher cost of MTA is justified in symptomatic cases, as it will be more cost effective in the long run to avoid an expensive re-treatment or pre-mature loss of tooth.

A limitation of the study is its low sample size. The clinical procedures were not performed by a single operator, which is a potential confounding factor in the study. Prospective studies and randomized clinical trials are needed in this regard to explore the variable of pre-operative pain in studies on pulpotomy in primary teeth.

5.CONCLUSIONS

The results of the current study suggest that the presence of pre-operative pain negatively affects the success of pulpotomy in primary molars, and could be used as an important clinical indicator to predict the health of the remaining radicular pulp. The presence of preoperative pain indicates a possible underlying inflammation, which will yield better outcome when treated with a bioactive material such as MTA, which has regenerative properties compared to FC. The study offers evidence for further research in this regard.

References

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