Retention and Caries-Preventive Outcomes of Glass Ionomer-Based Fissure Sealants in Children: A 24-Month Split-Mouth Randomized Controlled Trial
Phase: NA
Conditions: Fissure Sealant
Sponsor: Izmir Katip Celebi University

Study Protocol with Statistical Analysis Plan 
 
 
TİTLE: Retention and Caries-Preventive Outcomes of Glass Ionomer–Based Fissure 
Sealants in Children: A 24-Month Split-Mouth Randomized Controlled Trial 
DOCUMENT DATE: 30.01.2025  
RCT: The study was approved by the Medical Ethics Committee of Izmir Katip Celebi 
University, under report No. 14/100 
STUDY PROTOCOL:  
This randomized, controlled, double-blind clinical trial was approved by the Ethics Committee 
of Izmir Katip Celebi University (Approval No: 14/100). Informed consent was obtained from 
parents, and the study adhered to CONSORT guidelines. A total of 200 healthy children (ASA 
I), aged 6–12 years, each with two fully erupted permanent mandibular first molars (400 teeth), 
were enrolled. Using a split-mouth design, one molar received a high-fluoride glass ionomer– 
based sealant (Fuji Triage, GC Corp., Tokyo, Japan; control), while the contralateral molar was 
treated with either a CPP-ACP–containing sealant (Fuji VII EP, GC Corp.) or a nano-
fluorohydroxyapatite–based sealant (GCP Glass Seal, GCP Dental, The Netherlands). Sample 
size was calculated using G*Power 3.1.9.7, assuming an effect size of 0.40, α = 0.05, and power 
= 0.80, yielding a minimum of 88 teeth per group. Considering a 15–20% potential loss, the 
final sample included 400 teeth. Inclusion criteria comprised children demonstrating 
cooperative behavior (Frankl scores 3–4) and having deep fissures without caries (ICDAS II; 
DIAGNOdent ≤15). Exclusion criteria included systemic disease (ASA ≥ II), uncooperative 
behavior, enamel defects, or inability to attend follow-ups. Bitewing radiographs excluded 
proximal caries. Two calibrated examiners (Cohen’s k ≥ 0.8) conducted the study. Screening 
of 295 children included health history, caries risk assessment (Cariogram software, Malmö 
University), and inclusion of those with moderate caries risk. Randomization was two-phased: 
material pairing (Fuji Triage–GCP Glass Seal / Fuji Triage–Fuji VII EP) was determined using 
an online randomizer, while tooth allocation (right/left) was assigned by coin toss. Blinding 
was maintained for participants and evaluators. Before sealant application, baseline data (age, 
sex, oral hygiene, ICDAS II, and DIAGNOdent scores) were recorded. Teeth were cleaned and 
isolated; materials were applied per manufacturers’ instructions. For Fuji materials, cavity 
conditioner was used for 10 s, followed by sealant placement, coating, and 20 s LED curing. 
GCP Glass Seal involved EDTA cleaning, 60 s light-curing, and surface coating with GCP 
Gloss. All restorations were inspected for marginal adaptation and polymerization, and 
occlusion was adjusted. Oral hygiene instructions were provided. Follow-up evaluations were 
conducted at 3, 6, 12, 18, and 24 months by a blinded examiner. Retention, marginal integrity, 
discoloration, and secondary caries were assessed using modified USPHS criteria. Retention 
was graded (1 = complete, 2 = partial, 3 = total loss); further caries evaluation (ICDAS II and 
DIAGNOdent) was performed for scores 2–3.  

STATİSTİCAL ANALYSİS PLAN  
Data were analyzed using IBM SPSS v21. Descriptive statistics were expressed as mean ± SD 
or percentage. Normality was assessed with the Kolmogorov–Smirnov test. Non-parametric 
tests (Friedman, Kruskal–Wallis with Bonferroni correction) were used where appropriate. 
Categorical data were analyzed using Fisher-FreemanHalton, Pearson chi-square, or Fisher’s 
exact tests. Kaplan–Meier curves and log-rank tests compared material survival. Statistical 
significance was set at p < 0.05.