The aim of this clinical study was to evaluate the effects of different isolation methods and material filler ratios on the retention rates of two different fluoride-containing fissure sealants over an 18-month period.

Methods:

A total of 100 children (200 teeth) participated in this randomized, single-blind, split-mouth clinical trial. The mandibular permanent first molars of each participant were divided into two groups: one receiving a highly filled fluoride-releasing fissure sealant (Fissurit FX, Voco, Germany), and the other an unfilled fluoride-releasing sealant (Teethmate F-1, Kuraray, Germany). Each material group was also divided into two subgroups based on the isolation method used: rubber dam or cotton roll isolation. Sealant retention rates were evaluated at 6-, 12-, and 18-month follow-up visits. Data were statistically analyzed using a 0.05 significance level.

The aim of this randomized, controlled clinical trial was to assess (i) the retention rates of two different resin-based fissure sealant materials-one containing a high filler content and the other unfilled, both fluoride-releasing-and (ii) the effect of the isolation method (rubber dam versus cotton roll isolation) on sealant retention. Additionally, the study evaluated the effectiveness of these materials and isolation techniques in the prevention of dental caries. The null hypotheses tested were: (i) there is no significant difference in the retention rates between the two types of resin-based fissure sealants, and (ii) the type of isolation method employed does not significantly influence sealant retention.

Study Design:

This randomized, controlled, single-blind clinical trial was approved by the Medical Ethics Committee of Izmir Katip Celebi University (Approval No: 2025/059). Prior to the commencement of treatment, written informed consent was obtained from the parents or legal guardians of all participants. The study was conducted in accordance with the CONSORT (Consolidated Standards of Reporting Trials) guidelines to ensure the transparency and integrity of the methodology and results.

The study included 100 healthy children between the ages of 6 and 12 years (mean age: 7.9 years), all classified as ASA Class I (American Society of Anesthesiologists) and exhibiting cooperative behavior, as determined by a Frankl Behavior Rating Scale score of 3 or 4. All participants had fully erupted mandibular first permanent molars on both sides (totaling 200 teeth) requiring the application of pit-and-fissure sealants.

The clinical procedures were conducted by two trained investigators: one responsible for the baseline examination and treatment, and the other-blinded to the materials and methods used-responsible for follow-up assessments. Examiner calibration was performed at 20 randomly selected sites, and agreement was considered acceptable upon achieving substantial inter-examiner reliability (Cohen's Kappa ≥ 0.7).

Prior to enrollment, 178 children were screened by the primary operator, who assessed caries presence using visual inspection based on ICDAS criteria. Participants' medical and dental histories were recorded, and a clinical examination was performed using a blunt explorer and mouth mirror. Radiographic evaluation, including bilateral bitewing radiographs, was conducted to ensure the absence of dental caries in the target molars.

Caries risk assessment was performed using the Cariogram software (CarEng, version 3.0, Malmö University, Sweden). Factors included in the risk profile were: caries experience (DMFT/DMFS indices, new caries within the past year, existing restorations and missing teeth), presence of systemic conditions, dietary habits (particularly sugar intake), frequency of meals and snacks, Silness-Löe Plaque Index scores, Streptococcus mutans levels in saliva (assessed via strip test), fluoride exposure, salivary flow rate (stimulated saliva test), and salivary buffer capacity (measured using Saliva-Check Buffer or equivalent strip tests). Only patients identified as having a moderate risk of caries were included.

Eligible participants were enrolled following informed consent and child assent. Evaluation of the pit-and-fissure sealants was conducted at 6-, 12-, and 18-month recall appointments to monitor the presence of carious lesions and sealant retention. Assessments were performed by a calibrated pediatric dentist who remained blinded to the materials used. Prior to evaluation, teeth were cleaned with a toothbrush, air-dried, and examined under appropriate illumination. Caries lesions were recorded using the ICDAS II criteria, and sealant retention was classified as follows:

1. = Complete retention
2. = Partial loss
3. = Complete loss

Sealants exhibiting complete loss at any recall visit were re-applied; however, such teeth were withdrawn from further statistical analysis and recorded as failures throughout the remainder of the follow-up period.

Inclusion Criteria:

• The study comprised 100 healthy children aged between 6 and 12 years
• ASA class I (American Society of Anesthesiologists),
• exhibit cooperative behavior with a score of 3 or 4 on the Frankl Behavior Rating Scale.
• All participants has to be fully erupted lower first permanent molars on both sides (200 teeth), which required the application of pit and fissure sealants.
• The inclusion criteria is based on the International Caries Detection and Assessment System II (ICDAS II) criteria, including deep and retained pits and fissures, no restorations, and no evidence of caries lesions

Exclusion Criteria:

• Participants with special needs or systemic disease (ASA classification II or higher),
• requiring emergency dental care,
• suffering from a severe gag reflex or an allergy to latex,
• exhibiting uncooperative behavior (Frankl Score 1 or 2),
• exhibiting molars with anomalies of the enamel/dentin, or
• unable to attend follow-up appointments were excluded from the study.

A split-mouth study design was implemented, in which two distinct fissure sealant materials were applied using two different isolation techniques. Each participant received both types of sealants-one placed under rubber dam isolation and the other under cotton roll isolation. To reduce the risk of allocation bias, the assignment of sealant materials and isolation methods to specific teeth was randomized. A computer-generated randomization list (Research Randomizer, Version 4.0) was used to determine both the order of sealant application and the side (right or left mandibular molar) to which each material would be assigned. Based on the combination of sealant type and isolation method, this process resulted in the creation of four distinct study groups.