Full pulpotomy versus root canal therapy in mature teeth with irreversible pulpitis: a randomized controlled trial (2024)

Background

Vital pulp therapy (VPT) is recommended as an alternative treatment to root canal therapy (RCT) for management of teeth with carious pulp exposure. This randomized clinical trial aimed to compare the outcomes and postoperative pain, and to evaluate the time and cost after full pulpotomy (FP) and RCT in mature molar teeth with irreversible pulpitis (IP).

Methods

A total of 160 mature molar teeth with IP were randomly divided into two treatment groups. The FP group (test group) was treated with FP using iRoot BP Plus by an endodontist, the RCT group (control group) was treated with RCT using iRoot SP as sealer by the same endodontist. Pain was recorded preoperatively and daily until day 7 postoperatively. The treatment time and cost were recorded. Clinical and radiographic assessments were collected, and pulp sensibility tests were done by electric pulp test (EPT) at 3-, 6-, 12- month postoperatively. Data were analyzed through chi-square test, Mann-Whitney U test, Fisher exact and independent t test.

Results

FP and RCT had comparable success rates (Clinical, 97.3% vs. 98.6%; radiographic, 93.3% vs. 94.6%) (P > 0.05). Pain levels decreased over time from day 1 to day 7 postoperative in both groups, and the FP group had larger reductions in pain intensity than RCT at day 1 (P < 0.05). In the FP group, there were 5, 3 and 3 unresponsive teeth with EPT at 3-, 6- and 12- month follow-ups, respectively. The treatment time and cost in the FP group were significantly lower than in the RCT group (P < 0.05).

Conclusions

FP could be an appropriate alternative treatment for management of mature teeth with IP in short follow-up.

Trial registration

The trial was registered in Chinese Clinical Trial Registry (ChiCTR2200063380 at 05/09/2022).

Irreversible pulpitis (IP) caused by carious pulp exposure is a common infectious disease of dental pulp. For many years, the tooth with IP has traditionally been managed with root canal therapy (RCT) [1, 2]. However, several epidemiological studies have showed a lower percentage of success (24–66%) with RCTs, which could be due to inadequate RCTs mainly treated by general dentists [3, 4]. Meanwhile, the disadvantages of RCT are expensive, time-consuming [5]. It is also a non-conservative and non-biological treatment [6], because of removing all the vital pulp, which can result in root fractures. Giving these challenges with RCT, attention has shifted towards more conservative, biological alternatives, such as vital pulp therapy (VPT) [7, 8]. According to the “American Association of Endodontists (AAE) Position Statement on VPT”, the focus of VPT is broader; VPT can be considered as the suitable treatment for the mature teeth with IP when proper diagnosis and appropriate evaluations have been done [9]. The growing body of evidence has showed that the treatment outcomes of VPT could be equivalent to RCT in molars with IP [10,11,12], and encouraged endodontists to choose the bio-regenerative treatment [13].

An ideal bioceramic material for VPT must be antibacterial, biocompatible, have good sealing properties, and be able to induce the regeneration of dentine-pulp complex [14]. A systematic review has recommended to use mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, and Biodentine in VPT [15]. iRoot BP Plus (Innovative Bioceramix Inc, Vancouver, BC, Canada) is a recently developed bioceramic material that exhibits favorable biocompatibility and possesses the capability to stimulate mineralization and odontoblast development. These properties are comparable to those of MTA when utilized in pulpotomy procedures on dog teeth [16]. Furthermore, it exhibits superior clinical handling capabilities and can substitute for MTA and Calcium Hydroxide (Ca(OH)₂) in the pulpotomy procedure for permanent teeth [17, 18]. However, few studies have investigated the clinical iRoot BP Plus application in IP treatment, which is still needed.

Recently, there has been a growing trend in patient-centered care. Pain control is an important part of clinical practice. Despite significant advancements in RCT, over 50% of patients still suffer from postendodontic pain [19], which is a multifactorial phenomenon. The pain can seriously impact oral health-associated quality of life. According to Galani et al., full pulpotomy (FP) provided faster pain relief compared to RCT [20]. The rapid pain relief following pulpotomy was attributed to a decrease in local tissue pressure as well as inflammatory mediators levels, besides the severing of terminal endings of nociceptive sensory neurons [21]. However, further prospective work is required in order to confirm the beneficial impact of this treatment approach [22, 23].

Futhermore, researchers have recently suggested that cost-effective analysis should be considered for evaluating the benefits of VPT. One well-conducted economic evaluation by using a Markov Model found that: comparing with RCT in most cases, direct pulp capping (DPC) was cost-effective when the willingness-to-pay (WTP) ceiling value was adjusted from 0 to 250 euro. Sensitivity analyses found that DPC was more expensive and less cost-effective in teeth with a proximal pulp exposure site, in patients over 40 years of age [24]. However, this analysis was based on a single patient, system and costing data of German, not on larger study, which may not reflect current Chinese pricing.

This study aimed to compare the clinical and radiographic outcome of FP and RCT in mature molar teeth with IP, to compare the pain intensity and reduction, and to evaluate the time and cost after both treatment procedures. The hypothesis of the study was that FP has a similar success rate in comparison to RCT, it can reduce pain intensity effectively in the same way that RCT does, and has reasonable treatment time and cost comparable with RCT.

Trial design

This is a single-blinded, single-center, randomized controlled trial. This trial was conducted in the Shanghai Xuhui District Dental Center in 2022. The study protocol was authorized by the ethics committee of Shanghai Xuhui District Dental Center (XYF AF/SC-08/01.0) and registered in Chinese Clinical Trial Registry (ChiCTR2200063380 at 05/09/2022).

Inclusion and exclusion criteria

The inclusion and exclusion criteria were based on Asgary`s research [11] and American Association of Endodontists (AAE) guidelines [9]. Inclusion criteria were the following:

Molar teeth with deep caries exposing the vital pulp (a cold spray or electric pulp tester was used pre-treatment, and a visual pulpal hemorrhage inspection was conducted following the preparation of the access cavity).

Molar teeth with a history of spontaneous, radiating pain indicated IP, and the pain triggered by hot/cold fluids lasted for several minutes after removing of the stimulus. Molar teeth with no prominent radiolucency at the periapical or furcation regions. Patients aged 18–50 years of age. Patients who can be followed up according to the trial. Patients who approved and signed the written informed consent.

Exclusion criteria were the following:

Teeth with continuous bleeding (uncontrolled bleeding after FP with 10min, or invisible bleeding from 1 or more of the orifices, suggesting necrosis). Teeth could not be restored with direct restoration. Teeth having localized/generalized periodontal diseases (probing pocket depth more than 3mm). Teeth with crack fracture. Teeth with internal/external root resorption. Teeth with pulp chamber/canal calcification. Patients who are pregnant/nursing women. Patients who are physically/mentally disabled.

Sample size

Sample size was calculated based on the previous clinical study [20], RCTs with vital pulp showed a 95.0% success rate [25]. Using PASS 15.0 software, setting the effect size = 0.8, two-sided α = 0.05, β = 0.2 (power = 80%), approximately 75 patients per treatment group were needed, assuming a 10% loss to follow-up, 160 patients were included and distributed equally between the two treatment groups.

Randomization

A 1:1 allocation ratio was used to assign the patients to the FP group (test) or the RCT group (control) using an online random-number generator (www.randomization.com). Before the treatments, the patients and operator were blinded to the group allocation. The patients were examined and treated by an endodontist (operator). In order to guarantee proper randomization, sequentially numbered opaque sealed envelopes were used. In the allocation process, a research assistant, not involved in the assessment and recruitment of the patients, selected one envelope from among the 160 sealed envelopes, which is designated for FP or RCT (Fig.1).

Clinical Procedure

The teeth were anesthetized with 4% articaine with adrenaline 1/100,000 (Septodont, Saint-Maur-des-Fossess Cedex, France), isolated under rubber dam (Coltene, USA), and sterilized using a cotton pellet soaked in 2.5% sodium hypochlorite (NaOCl). Then carious leisons were removed by using a fresh sterile high-speed diamond bur under copious water irrigation. Upon pulp exposed, the cavity was rinsed with 2.5% NaOCl. The other steps of the treatment proceeded accordingly:

FP Group

The procedure FP involved the removal of all coronal pulp tissue to the canals orifices level through a fresh sterile high-speed diamond bur under the microscope (Zumax, China). Hemostasis was accomplished by compressing a cotton pellet soaked in 2.5% NaOCl over the radicular pulp tissue for 5min. Then, irrigation with amount of sterile 0.9% sodium chloride (NaCl) solution was gently conducted. Once hemostasis was achieved, the radicular pulp tissue was observed under the microscope, which should present as uniformly reddish pink color. Subsequently, a new type of premixed pulp-capping materials, iRoot BP Plus (Innovative Bioceramix Inc, Vancouver, BC, Canada) was prepared according to the manufacturer`s instructions, and a 4-mm layer was directly adapted over the radicular pulp tissue, ensuring that there was not any excess materials on the pulp chamber walls. The access cavity was restored with a liner (Vitrebond; 3M ESPE, Seefeld, Germany) and composite restoration (Z350, 3M ESPE) all completed in a single visit. Then postoperative radiographs were taken.

RCT Group

RCT was conducted in two visits. At the first visit, the pulp tissues were removed from all the root canals, identifying and enlarging canal orifices via Sx ProTaper Gold rotary (Dentsply Maillefer), determing the working length with an apex locator (Morita Dentaport Root ZX; J. Morita, Irvine, CA). The root canals preparation was conducted by rotary nickel-titanium files, irrigated by using 2.5% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA), and disinfected by using Ca(OH)₂. At the second appointment, scheduled after 7 days, the obturation was performed with gutta-percha and iRoot SP (Innovative Bioceramix Inc, Vancouver, BC, Canada) as sealer, using single cone technique.The access cavity was restored with a liner and resin composite restoration during the same appointment while using rubber dam isolation.

Outcome evaluation and recall protocol

The patients were recalled for clinical and radiographic examination at 3, 6 and 12 months. The evaluation of clinical success was performed in both groups based on similar criteria. The treatment was deemed successful if patients exhibited no spontaneous pain beyond the first few days, no swelling, sinus tract, or deep periodontal probing, and maintained an intact restoration. Radiographically, FP was considered successful if there was no root resorption or furcal bone loss, periapical index (PAI) ≤ 1 [26]. For RCT, the case was considered successful if there was a normal periapical area with no lesion, PAI<3, no root resorption. For radiographic evaluation, blinding of the evaluators was impossible due to the apparent differences between the two groups. Two endodontists evaluated independently. When disagreement occurred, the evaluation was repeated 3 weeks later, disagreements were discussed by two endodontists to reach a consensus.

Pain intensity were measured using the 11-point (0–10) numeric rating scale (NRS). Pain on the NRS was categorized as four grades, no pain (0), mild pain (1–3), moderate pain (4–6), and severe pain (7–10). The investigators recorded the preoperative and postoperative pain intensity every 24h until the 7 days after the first visit by contacting the patients on the phone. In the RCT group, the treatment was performed in 2 visits, pain intensity was recorded after each visit and higher pain level was taken into account for the analysis.

The time and cost of treatments were recorded by one nurse. We defined the total treatment time from administration of local anesthesia to the placement of composite restoration. In the RCT group, the time and cost were recorded in sessions, the 2 sessions were added together at the end.

Pulp sensibility test in the FP group was done at 3-, 6-, and 12- month post-treatment by electric pulp test (EPT) (Denjoy, China). During the pulp sensibility test, the control teeth (intact teeth of contralateral homonymous, opposite jaw homonymous, or adjacent) were tested first, then followed by the teeth in the FP group.

Statistical analysis

Data analyses were carried out through SPSS version 22.0, expressing data as means, standard deviations, and percentages and setting P < 0.05 as the significance level. The chi-square test and Mann-Whitney U test were utilized to compare proportions and mean pain scores, respectively. The success rate of two groups were evaluated by using Fisher exact. The treatment time and cost were analyzed by using independent t test.

The Cohen`s kappa coefficient was 0.71, indicating substantial agreement. The bleeding time in the FP group was 2–5min. Table1 displays the baseline features of participants and teeth.

Pain intensity

The patients completed the assessment during the initial week, the preoperative pain intensity in the FP and RCT groups were 8.0 and 7.8, respectively. Pain levels decreased over time from day 1 to day 7 postoperative in both groups, the average pain intensity in the FP group was larger reduction than RCT, but at day 1 there was significant difference (mean 2.3 and 5.5, respectively; P = 0.031) (Fig.2). In the FP group, 2 of 76 patients experienced enduring pain and received RCT at 1 month.

Treatment outcome

At 12- month follow-up, the recall rate in the FP group was 93.7%, with 2 failure that needed RCT. Seventy-three of 75 teeth were successful clinically and seventy radiographically (97.3%, 93.3%). In the RCT group, six patients did not come to recalls, the recall rate was 92.5%, with 1 failure that needed extraction. Seventy-three of 74 teeth were successful clinically and seventy radiographically (98.6%, 94.6%). Radiographically, 3 cases failed because of periapical lesion enlarged, a new lesion developed, and 1 case root fracture.

Pulp sensibility test

Figure3 showed that in the FP group there were 5, 3, and 3 unresponsive teeth with EPT at 3-, 6- and 12- month follow-ups, respectively. Though the other teeth were all responsive, the values of EPT in postoperative were higher than preoperative(Fig.4).

Comparison of treatment time and cost

Treatment time spans were 43.5min and 112.5min in the FP and RCT groups, respectively (P = 0.020) (Fig.5). The average costs of molars were RMB 882 and RMB 1985.5 (RMB 1 = 0.141 USD) in the FP and RCT groups, respectively (P = 0.022)(Fig.6).

IP caused by carious pulp exposure is a common disease in adults. In the past, the pulp of teeth diagnosed with IP was considered no capable of healing, should be completely removed by RCT. According to the histologic study of Ricucci et al., clinical signs and symptoms of patient are not well correlated with the actual extent of inflammation of the exposed pulp [27]. Hence, RCT is not the only choice for teeth with IP, VPT can be considered an suitable treatment for such cases.

Lacking of a clear clinical criteria, there is still debate on whether to choose RCT or VPT for teeth with a clinical diagnosis of IP. This randomized controlled trial aimed to compare the treatment outcome, the pain intensity and reduction, and the time and cost between FP and RCT.

The first part of the hypothesis was accepted in terms of comparable clinical and radiographic outcome after 12 months follow-up. The second and third part was rejected because FP was superior to RCT in few aspects of pain relief, treatment time and cost.

In our study, the results have shown that the clinical and radiographic success rate were 97.3% and 93.3%, respectively, in the FP group, as compared to RCT group (98.6% and 94.6%). These results, similar to many previous studies [5, 10, 11, 28], show that FP can be considered an appropriate alternative for RCT in mature teeth with IP. A recent systematic review concluded that VPTs, especially FP, have a high success rate in managing cases with IP [29]. In this study, FP was directly chosen, rather than pulp capping or partial pulpotomy [30, 31].

Pain is the most common symptom of pulpitis; roughly around 90% of emergency visits because of pain [32]. All teeth included in our study were initially symptomatic with moderate to severe spontaneous or lingering pain, the mean preoperative NRS scores of two groups were comparable, the severity of the associated pain decreased significantly within 1day after treatment and continued to decline to the lowest level within 7 days. In the FP group, about 30% of patients reported complete pain relief (score 0) 1day later, pain decreased significantly than the RCT group. The result followed another randomized clinical study [20], which reported greater and more significant pain relief with FP, with most of patients having no pain or mild pain by the second day. The reason of the quick pain relief after pulpotomy is that the local tissue pressure and inflammatory mediators levels have been decreased, and the terminal endings of nociceptive sensory neurons have been severed. Compared with FP, RCT resulted in higher incidence of postoperative pain. There are several reasons for post-RCT pain, one possible reason is periapical tissue contamination and irritation caused by root canal instruments. The instrumentation procedure may induce mechanical, chemical, and/or microbial damage to the periradicular tissues [19]. Inflammation can result from the extrusion of dentinal debris, pulp tissue, microorganisms, and irrigants into the periapical tissues [33]. The severity of pain is correlated with the degree of tissue damage. Hence, as a permanent treatment for IP, FP is better than RCT in short-term pain relief.

The choice of pulp-capping materials significantly impacts the prognosis of VPT. iRoot BP Plus is a novel premix material, which is easy to operate and has good biocompatibility and physicochemical properties. According to the manufacturer`s recommendations, the thickness of 4mm capping material can prevent microleakage through the gaps at the material-dentin interface or in the material itself following material shrinkage. Several researchers have examined the impact of iRoot BP Plus as a pulp-capping material on mature permanent teeth, showing the success rate of 98%, 89% and 81% at 1, 2 and 3 years, respectively [34]. In this study, employing iRoot BP Plus as a pulp capping material in FP resulted in a high success rate comparable to that of RCT. This suggests that iRoot BP Plus can be used as an alternative to RCT for treating mature molar teeth with IP.

The procedure of FP is simple and easy, but the challenge and difficulty are how to predict the health of the remaining pulp tissue. In this study, during the follow-up, EPT were examined. In the FP group, 5 teeth were unresponsive to EPT at 3-month follow-up, 2 of which regained responsive at 6-month follow-up, and 3 others remained unresponsive until 12-month follow-up. There was no clinical discomfort in these 3 cases, with no prominent radiolucency at the periapical, and no dentin bridge formation was found on radiography. The reason why these 3 cases did not respond to EPT and had no clinical symptoms may be that the deep restoration may undermine the reliability of pulp sensibility tests, the pulp tissue had an increase in fiber components. It may be also possible that the pulp has developed chronic necrosis. EPT has high specificity, it is more likely to correctly identify vital teeth (specificity = 0.93), but low accuracy when assessing nonvital teeth (sensitivity = 0.72) [35]. The key point in determining pulp vitality is the integrity of the pulp blood supply. Recent years, it has been suggested to use laser Doppler flowmetry (LDF) to monitor the blood supply of pulp tissue, and oxygen monitor (OXY) to monitor the oxygenation of pulp tissue. LDF and OXY can objectively, effectively and non-invasively judge the real state of dental pulp, independent of patients` subjective sensation [36, 37].

Patients in the FP group achieved high general satisfaction, because of the time and cost consumption, which is consistent with previous studies [38, 39]. In our study, although RCT was completed in two visits, it needed more time-consuming and more challenging than FP, and there were 3 cases failed because of periapical lesion enlarged, a new lesion developed, and 1 case root fracture. Meanwhile, RCT costed twice as much as FP. One previous study in dentistry had utilized a Markov simulation model to evaluate the cost-effectiveness of pulpotomy compared to RCT for the management of IP in mature permanent teeth, based on United States healthcare, pulpotomy was an acceptable cost-effective treatment option at lower WTP values whereas RCT was a cost-effective treatment at higher WTP values [40]. However, there is a different payment system for health insurance in China, it is advisable to conduct studies with a greater number of participants and longer periods of observation in order to confirm the findings.

Our study had some limitations. First, the apparent differences of radiographic assessments between the two groups, conducting a blinded study as impossible, inevitably brought about bias. An additional limitation was the short follow-up period, which has limited in detecting pulpal and periapical disease processes.

VPT:

Vital pulp therapy

RCT:

Root canal therapy

FP:

Full pulpotomy

IP:

Irreversible pulpitis

EPT:

Electric pulp test

AAE:

American Association of Endodontists

MTA:

Mineral Trioxide Aggregate

CEM:

Calcium-enriched mixture

Ca(OH)₂ :

Calcium hydroxide

DPC:

Direct pulp capping

WTP:

Willingness-to-pay

NaOCl:

Sodium hypochlorite

NaCl:

Sodium chloride

EDTA:

Ethylenediaminetetraacetic acid

NRS:

Numeric rating scale

LDF:

Laser Doppler flowmetry

OXY:

Oxygen monitor

Authors and Affiliations

1. Shanghai Xuhui District Dental Center, Shanghai, 200032, China

   Lina Zhu,Xuetao Deng,Zhen Chen,Jiaxin Chen&Wenhao Qian

2. Department of Oral Medicine, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China

   Wei Liu

Contributions

LW and QWH: Conceptualization, methodology and Supervision. ZLN, DXT and CZ: Data collection. CJX: Data analysis. ZLN: Writing, original draft preparation, reviewing and editing. All authors reviewed the manuscript.

Corresponding author

Correspondence to Wenhao Qian.

Ethics approval and consent to participate

The study was approved by the Ethical committee of Shanghai Xuhui District Dental Center (protocol code: XYF AF/SC-08/01.0). We confirm that all methods were performed in accordance with the relevant guideline and regulations. The experiments were performed in accordance with the Declaration of Helsinki. Informed consent was obtained from all participants involved in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

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