The trial aimed to evaluate the sealant retention, patient's preference and chair time needed during pit and fissure sealant placement under two isolation techniques [Dryshield system (DS) and cotton roll isolation (CRI)] in a university setting.

In children, 80-90% of dental caries is found in the pits and fissures of the posterior permanent teeth. Pit and fissure sealants (PFS) can be used effectively to prevent dental caries. When applied correctly, dental PFS accomplish three main objectives: preventing dental caries development, hindering dental caries development in its initial phases, and inhibiting the spread of bacteria that cause dental caries. To be effective, PFS need to be applied under sufficient moisture control around the specific teeth undergoing treatment. Therefore, proper isolation of the teeth is one of the most important steps when placing sealants to ensure their retention.

Cotton roll isolation (CRI) has been widely used for sealant placement, and is the most common method among pediatric dentists. However, the placement of cotton rolls on the lateral part of the tongue or inadequate isolation during CRI has both been reported to produce gagging, tasting the contents and requiring frequent replacement of the wet cotton rolls.

A previous study demonstrated that new moisture control systems such as Isolite, produce sealant retention rates comparable to cotton roll isolation, while decreasing procedure time. DryShield (DS) has recently been introduced as an all-in-one isolation system. It is similar to the Isolite as it combines the tasks of fluid evacuation, tongue and cheek retraction, and serves as a bite block, but differs in that it is autoclavable and does not provide illumination. Its design allows it to suction and isolate half the oral cavity at a time. Therefore, it should presumably facilitate sealants placement under a more controlled environment, while reducing chair time for the dentist.

Few trials have compared the PFS chair time and patient acceptance of DS to the CRI. The goals of this study were to evaluate patients' preferences, time efficiency, and retention of PFS using DS compared to CRI in a single randomized clinical study.

Inclusion Criteria:

1. Healthy patients with no compromising medical or physical condition
2. age ranging from six to 12 years old;
3. patients with at least one caries-free permanent molar in any quadrant, with normal anatomy, who qualified for pit and fissure sealant application with an International Caries Detection and Assessment System (ICDAS) score of 0-2.
4. no prior sealants or restorations on the teeth under study;
5. no cavitated carious lesions;
6. cooperative patients (classified as 3 or 4 according to the Frankl Behavioral Rating Scale)
7. legal guardian consents and approved assents to the child's participation in the study.

Exclusion Criteria:

1. a history of chronic disease (e.g., epilepsy, ectodermal dysplasia, cardiac anomalies);
2. inability to return for follow-ups.
3. patients with molars that have partially erupted
4. a permanent molar with enamel flaws or abnormal anatomy
5. children who are uncooperative, with a Frankl Behaviour Rating Scale of 1 or 2;
6. children who have a severe gagging reflex;
7. special needs children.
8. Those who do not provide appropriate assents or consents

The participants, care providers and the principle supervisor were not blinded since they know which isolation technique was used during the placement of sealant. But the outcome assessor was blinded and he assessed the sealants placement after 6, 12, and 18 months.