Introduction
What is the definition of a direct pulp cap?
A direct pulp cap is a procedure in which a medicament is placed directly over the exposed dental pulp.
What solution was used to control bleeding?
A cotton pellet moistened with 5.25% sodium hypochlorite was placed over the exposure
The cotton pellet soaked in 5.25% sodium hypochlorite is used to control bleeding and disinfect the exposure site. It helps achieve hemostasis and reduces the bacterial load at the pulp surface before placing the capping material, which is critical for pulp healing.
How many practices participated?
35
What were the failure rates?
The probability of failure at 24 mos was 31.5% for CaOH vs. 19.7% for MTA
The Kaplan–Meier analysis showed that teeth pulp-capped with CaOH failed more often over 24 months than those capped with MTA. A failure means loss of vitality leading to root canal therapy or extraction. This directly supports the conclusion that MTA has better long-term outcomes.
What research gap did this study address?
Hemorrhage control from pulp and disinfection of the exposure site or pulp chamber
Before this trial, there were relatively few well-designed clinical studies directly comparing CaOH and MTA in carious pulp exposures. Most data came from small or short-term studies, which made it hard to draw strong conclusions. This trial helps fill that evidence gap.
What material has traditionally been the gold standard?
Calcium hydroxide (CaOH) has been considered the ‘gold standard’ of direct pulp-capping materials for several decades.
For many years, calcium hydroxide was the most commonly used material for direct pulp capping because it has antibacterial properties and is capable of stimulating dentin bridge formation. Historically, most of the literature and clinical protocols referred to CaOH as the reference material against which new agents were compared.
Who applied the pulp-capping agent?
The dentist
Only the dentist places the pulp-capping material because it is a key clinical decision and must be done correctly regarding thickness, location, and handling. This ensures standardization and reflects real-world practice in which the dentist is responsible for the procedure.
What was the minimum age?
All patients, ages 7 yrs or older
How many failures occurred in each group?
Forty-five CaOH pulp-capped teeth. 25 MTA pulp-capped teeth
There were more failures in the CaOH group (45) than in the MTA group (25). This numeric difference, combined with the time-to-event analysis, reinforces that teeth treated with MTA tended to survive longer without needing further intervention.
What did the study conclude?
There is evidence that MTA is more effective than CaOH.
The authors conclude that MTA is more effective based on its lower failure rates and better survival over time. When combined with prior clinical and histological studies, the current trial adds strong clinical support for using MTA instead of CaOH in direct pulp capping.
What did the Cochrane Review conclude?
Evidence is lacking as to the most effective pulp-capping material.
The Cochrane Review mentioned in the article highlighted that, despite the long use of CaOH and the introduction of newer materials like MTA, there was still not enough high-quality clinical evidence to definitively state which pulp-capping material was superior. This justified the need for well-designed randomized clinical trials such as this one.
What liner material was used?
A resin-modified glass-ionomer liner (Vitrebond…) was placed over the pulp-capping agent
Vitrebond (RMGI) is placed over both CaOH and MTA to protect the capping material and improve theseal under the final restoration. It helps prevent contamination, distributes forces, and provides anadditional barrier before the permanent restoration is placed.
How was vitality assessed?
Pulp vitality was determined by the presence or absence of pulp bleeding
What was the unadjusted hazard ratio?
The unadjusted hazard ratio for CaOH vs. MTA was 2.15.
How did one practice influence results?
One practice experienced a high failure rate (56%)
One practice in the CaOH group had an unusually high failure rate, which influenced the overall results for that material. This raises the possibility that factors such as technique, case selection, or protocol adherence at that site may have contributed to poorer outcomes with CaOH.
What are two disadvantages of CaOH?
The disadvantages of calcium hydroxide are that it has no inherent adhesive properties and provides a poor seal
Calcium hydroxide does not bond to tooth structure and therefore does not provide a tight seal. In addition, self-cure formulations can dissolve over time. These limitations may allow microleakage andbacterial penetration, which can compromise pulp healing and increase the risk of failure.
When would the practitioner decide not to proceed?
This was repeated until bleeding was controlled or the practitioner decided that pulp capping was not appropriate.
If bleeding cannot be controlled even after repeated application of sodium hypochlorite, it suggests more extensive pulpal inflammation or irreversible damage. In that situation, the clinician may decide that vital pulp therapy is not appropriate and instead choose root canal therapy or another treatment option.
How was randomization assigned?
Randomization was done by practice rather than by patient
What was the adjusted hazard ratio?
The adjusted hazard ratio was 2.35 (95% CI, 1.19–4.66).
What operator-related bias may have affected results?
Dentists may have used a material with which they were less familiar
Most dentists in the network were more familiar with CaOH before the study and less experienced with
MTA. Despite this, MTA still performed better. The authors suggest that if practitioners had been equally familiar with MTA, its results could have been even more favorable, meaning the study may actually underestimate MTA’s potential.
What key advantage does MTA have?
MTA has a significant advantage in that it provides some seal to tooth structure.
MTA has better sealing ability compared with CaOH. This means it can adapt more tightly to dentin and reduce microleakage, helping to protect the pulp from bacteria and fluids. This improved seal is one ofthe main reasons why MTA performs better clinically in direct pulp capping.
Who determined the final restoration?
The teeth were restored as deemed appropriate by the dentist
The study allowed dentists to select the most appropriate definitive restoration (e.g., composite, amalgam, crown) based on the clinical situation. This reflects real-world practice and contributes to the external validity of the study, since the pulp cap was not limited to a single restoration type.
What determined the end of follow-up?
Followed for up to 2 yrs or until the tooth required extraction or root canal therapy.
Patients were followed either until the study ended (~2 years) or until the tooth failed and needed rootcanal treatment or extraction. This allowed the researchers to capture both early and late failures and to estimate survival over time using time-to-event analysis.
What statistical method was used?
Kaplan-Meier estimate. 31.5% for CaOH vs. 19.7% for MTA
Kaplan–Meier curves were used to estimate the probability of survival (no failure) over time while accounting for censored data (patients who did not complete all follow-up visits). This statistical method is standard in clinical trials that look at time-dependent outcomes like failure or survival.
What supports cumulative superiority?
There is cumulative evidence for MTA superiority
The trial’s results are consistent with previous human and animal studies showing better histologic and clinical outcomes with MTA. Taken together, these multiple lines of evidence create a cumulative case that MTA is superior to CaOH as a direct pulp-capping material, both biologically and clinically.