Introduction
Dental caries is a prevalent chronic disease, affecting 60-90% of school-age children in
industrialized countries; although in the last four decades the prevalence and severity of
caries lesions have decreased, it is still a frequent disease for this age group. The
American Dental Association (ADA) classifies dental caries by clinical presentation as
initial, moderate, and severe; furthermore, the ADA classifies the disease using the
international caries detection and diagnosis system (ICDAS II; International Caries Detection
and Assessment System II) and by a radiographic presentation of the proximal faces based on
the E0-E2, D1-D3 notation system. Within the non-vital pulp treatments, pulpectomy is
indicated in temporary teeth; pulpectomy is a conventional endodontic treatment for teeth
with exposed, infected, and/or necrotic tissue to eliminate pulp and periradicular infection.
In a recent systematic review that compared three different strategies for the management of
deep caries lesions (i.e. complete caries removal, selective caries removal, and step caries
removal), Aïem and colleagues (2020) report an increased restoration failure risk when
selective removal is used compared to complete removal of caries. In a study where French
dentists were surveyed on the management of deep caries lesions in primary dentition, the
majority of respondents mentioned performing deep caries removal in a single step. Endodontic
procedures in the pediatric population can assist to keep temporary teeth until exfoliation,
which is a key principle of pediatric dentistry. Vital pulp and non-vital pulp treatments are
employed in the treatment of severe lesions and deep caries; meanwhile, pulpectomy is a
treatment largely used in the primary dentition. In pulp therapy, a pulpotomy is performed by
removing the pulp from the chamber, while in a pulpectomy, all the tissue from both the
chamber and the root canals is removed.
There are two parameters used to determine root canal treatment success: 1) the morphology
and shaping of the canal; and 2) the duct cleanliness or the adequate level of disinfection
provided by the type and quantity of intra-canal irrigation (e.g. chlorhexidine, sodium
hypochlorite, citric acid, profuse irrigation). A pulpectomy is the technique of choice for
primary dentition in deep carious lesions with pulp necrosis since pulpectomy has a higher
success rate than pulpotomy. While the time for access to the root canal is less with the use
of rotary instrumentation systems compared to a manual technique, manual techniques have the
same efficacy as rotary systems in root canal cleaning procedures. Rotary systems have
greater clinical success compared to manual techniques, in addition to having advantages in
instrumentation time, canal shaping, reduction in working time, better cooperation and less
patient fatigue, improvement in the conicity of the root canal, and promoting a higher
quality of obturation. In a recent meta-analysis, Manchanda and colleagues (2020) conclude
that rotary instrumentation has similar clinical and radiographic success rates to manual
techniques in primary dentition; additionally, rotatory techniques show lower levels of
postoperative pain and less instrumentation time. In the only study in the Mexican population
that compared a rotary system (i.e. K3) against a manual technique (i.e. K-file) it was found
that the instrumentation and obturation time was shorter, being a promising technique in
children.
Given the limited comparative literature about rotatory techniques used in pulpectomy
treatment, it is necessary to conduct clinical trials that compare both manual and rotatory
techniques in first dentition treatment. So far, studies have been carried out comparing
rotary systems designed for adults in the pediatric population. Recently, interest to
validate and implement safe and effective protocols for the management of rotary systems in
primary dentition has emerged in pediatric dentistry. Below is a protocol designed to
investigate the advantages and disadvantages associated with the use of rotary systems
designed for our population of interest.
Study design
Population: patients with pulpectomy indication according to the criteria mentioned by Kuo
and colleagues (2006).
Place: Pediatric Dentistry Clinic, Universidad Latinoamericana, Campus Valle.
Time frame: January 2021 - December 2021
Sampling technique: convenience sampling with group randomization.
Study groups: 4 (n= 100 teeth)
Patients who are treated with a manual pulpectomy and a K-file system.
Patients who are treated with a manual pulpectomy and a Kedo-SH system.
Patients who are treated with a rotatory technique pulpectomy and a K3 system.
Patients who are treated with a rotatory technique pulpectomy and a Kedo-S system.
PICOS framework
P: pediatric population
I: manual system pulpectomy
C: rotary system pulpectomy
O: instrumentation and obturation time, filling quality by radiographic evaluation,
postoperative pain levels at 12hr and 24hr, frequency of complications (e.g. fistulas,
thinning of the mesiodistal walls, periapical or furcation radiolucency) after a 3-, 6-, 9-,
and 12-month follow-up.
S: a randomized controlled trial
Research question
Are there differences between the use of a manual system compared to a rotary system in the
pediatric population?
Main objective
Compare the performance between a manual technique and a rotatory technique during
biomechanical work.
Particular objectives
Compare the instrumentation (i.e. during biomechanical work) and filling time between a
manual technique and a rotatory technique.
Compare the filling quality by radiographic evaluation between a manual technique and a
rotatory technique at the end of the procedure.
Compare postoperative pain levels using the visual analog scale at 12 and 24 hours.
Compare the frequency of complications (e.g. fistulas, thinning of the mesiodistal
walls, periapical or furcation radiolucency) after a 3-, 6-, 9-, and 12-month follow-up
between the two techniques.
Hypotheses
H1: The rotatory techniques will take less instrumentation and obturation time than the
manual techniques.
H1: The quality of the obturation in the rotatory technique will be reported radiographically
more frequently as optimal than the manual technique.
H1: The pain levels reported by patients will be lower in the rotatory technique than in the
manual technique.
H1: The rotatory technique will have a lower frequency of complications such as fistulas,
thinning of the mesiodistal walls, periapical or furcation radiolucency at each time point
compared to the manual technique.
Statistical analysis
Descriptive statistics will be performed on all variables. Statistical analysis will be
performed using SPSS 25 (SPSS Inc., Chicago, IL). All variables will be examined to determine
the existence of outliers and whether or not they meet the Gaussian distribution assumption;
furthermore, Gaussian distribution will be determined with the Shapiro-Wilk test and by
visualizing the data through histograms and Q-Q graphs. The demographic and clinical
variables will be summarized in proportions and percentages. Nominal variables will be
evaluated with Chi-square tests to assess differences between groups. Categorical variables
will be evaluated to determine statistical inferences with the Mann-Whitney test. Continuous
variables will be assessed for statistical inferences using t-tests and Levene's test to
assess variance equality. Statistical significance will be set at p= 0.05 and a Bonferroni
correction will be made for multiple comparisons.
Sample size
The sample size necessary to detect statistically significant differences was calculated by
taking the following parameters; α = 0.05 and statistical power of 0.8 (i.e. 1-β). For the
calculation of the sample size, the time of instrumentation was used as a measure of clinical
outcome. The sample was calculated based on the article by Ochoa-Romero and colleagues (2011)
where instrumentation time was used as the primary outcome. The sample calculator used can be
found on the website: https://clincalc.com/stats/samplesize.aspx. The calculator designed for
two independent groups for continuous variables was selected, using the mean for each group
(i.e. group 1: rotatory technique 1.7 minutes ± 0.5; group 2: manual technique 2.5 minutes ±
0.8) taking into account an enrollment 1:1 ratio for this study. The total sample size was 24
teeth (i.e. at least 6 teeth per group to find statistically significant differences in
instrumentation time).
