Effectiveness of Dryshield system vs. cotton roll isolation on sealant’s retention, placement time, and children’s acceptance in a dental school setting

2.1 Eligibility criteria

The inclusion criteria were as follows: (1) healthy patients with no medical conditions; (2) ages ranging from seven to twelve years old; (3) at least one fully erupted first permanent molar free from caries; (4) molar tooth with normal anatomy; (5) molar tooth with an International Caries Detection and Assessment System (ICDAS) score of 0–2; (6) no previous sealants or restorations on the molar under investigation; (7) cooperative patients; and (8) consent from the legal guardian for participation in the study.

The exclusion criteria were as follows: (1) history of chronic disease; (2) inability to attend follow-up visits; (3) partially erupted molars; (4) permanent molar with enamel defect or abnormal anatomy; (5) uncooperative behavior—Frankl Behaviour Rating Scale of 1 or 2; (6) Allergies to latex; (7) Severe gag reflex.

2.2 Sample size

For power analysis for a repeated-measures experiment in G*Power software (version 3.1.9.7, Heinrich Heine University Dusseldorf, Dusseldorf, NRW, Germany), an Analysis of Variance (ANOVA) was performed to compare the statistical significance of the mean retention rate using the two techniques (CRI and DS) to provide fissure sealants. An alpha of 0.05, a power of 0.80 (80%), and a medium effect size (f = 0.30) were used to calculate the required minimum sample size of 50 teeth in each group [25]. With a 10% expected attrition rate, n = 5 was added, resulting in a sample size of 55 teeth.

2.3 Screening of participants and randomization

A single experienced pediatric dentist (AA) screened each participant to determine eligibility for the study. Oral examination was conducted in the University clinic settings, by trained senior dental students, under headlamp light using dental mirrors and blunt probes to examine permanent first molars (PFMs). Two bitewing radiographs were taken as part of initial documentation and clinic admission. The PFMs were checked for the absence of dental caries or anomalies. Informed consent and assent were obtained from the parents/legal guardians and their children before the study commenced.

Randomization was done using R 2.11.1 software (R Foundation for Statistical Computing, Murray Hill, NJ, USA) to generate random numbers. Simple random allocation was used to ensure equal randomization for each isolation system. Each participant was provided with an envelope containing a printed participant number. Each number specified the isolation technique type and the application sequence assigned to that participant. Only one isolation technique was used for each participant.

2.4 Intervention

Each participant in the study received the sealant application in the university clinics from their primary care provider, a senior dental student (7th-year graduating student). The participants handed the envelope to the primary care provider to identify the isolation system and its technique. Ten senior students were involved in the study and were trained by an experienced pediatric mentor (AA). All PFS applications were performed under the close supervision of a single experienced pediatric mentor (AA). All clinical procedures were carried out using a strict aseptic sterile technique consistent with standard practice in the university dental clinic.

All PFMs were cleaned with non-fluoridated pumice paste using a low-speed handpiece and a prophylaxis polishing brush before isolation. The teeth were thoroughly rinsed and dried with a dental air spray. Finally, if any debris was present, a blunt instrument was used to check for it, and re-cleaning was performed as necessary.

2.5 CRI procedure

The operator used and secured a medium-sized #2 cotton roll (Cotton Roll, ASA Dental, Italy). For maxillary isolation, cotton rolls were positioned on the cheek side of the teeth in the buccal fold. For mandibular isolation, cotton rolls were placed in the mucobuccal fold and the lingual side of the arch of the mandible. Cotton rolls were replaced after each acid etch rinsing. A dental assistant handled a high-volume suction.

2.6 DS procedure

A pediatric mouthpiece (Dryshield Systems®, Marlborough, MA, USA) was selected. Petroleum jelly was applied to the participant’s lips. Instructions were given to participants to keep their mouths open. The mouthpiece was placed in the participant’s mouth, while the cheek shield component was folded forward toward the tongue retractor. The bite block component of the system was positioned on the occlusal surface. Then, the participant was instructed to bite down. Every procedure was done according to the manufacturer’s guidelines.

2.7 PFS procedure

Following the application of the isolation technique, each tooth was etched for 30 seconds with a 37% phosphoric acid dental etching gel (Ultra-Etch, Ultradent, Utah, USA) [26]. The etched tooth was thoroughly rinsed and dried for 15 seconds. After drying, the tooth was examined to ensure that the enamel was properly etched and had a frosty white appearance [27]. Resin-based pit and fissure sealant (3M ESPE, St. Paul, MN, USA) was applied to the tooth surfaces, ensuring it covered the pits and fissures. The material was placed approximately halfway-up the inclined plane of the cusp ridge. The sealant was a light-cure and low viscosity sealant with a unique patented white color. The occlusal and palatal fissures of the maxillary molars, as well as the occlusal and buccal fissures of the mandibular molars, were sealed. Any air bubbles present were removed using a sharp explorer or a micro brush. According to the sealant manufacturer, the sealant was cured for 20 seconds. Finally, the occlusion was checked, and any necessary adjustments were made with finishing burs. For each participant, all PFS placements were handled by a single operator with the help of a dental assistant.

2.8 Follow-up clinical evaluation

Clinical evaluation of patients at 6, 12 and 18 months of sealant placement, was conducted by a study supervisor acting as a blinded outcome assessor (QA). Follow-up clinical exams were performed using a mouth mirror and a dental probe in a dental chair. The criteria for evaluation were based on Simonsen’s criteria [24], which include the following:

■ Completely retained—If some peripheral fissures were uncovered following sealant wear, but no ledges were visible.

■ Partially retained—If, due to wear or material loss, part of a previously sealed pit/fissure was exposed.

■ Missing—No sealant detected.

If the sealant was completely intact during the follow-up, it was considered a “Success”. If the sealant was partially retained or missing, it was considered a “failure” and was resealed.

2.9 Placement time measurement

An assigned assistant measured the time in seconds, using a stopwatch for each isolation technique. The timing started with the placement of the first cotton roll for CRI and the insertion of DS. For each isolation method, the time measurement concluded when the isolation part was entirely removed from the mouth.

2.10 Interview-based questionnaire

Following the completion of each PFS, a six-item interview-based questionnaire developed from a previous study [19] was used to evaluate the participant’s acceptance of the isolation technique employed. The questionnaire was administered verbally at the end of the visit by an assigned dental assistant. Each participant was shown the isolation technique used; questions were repeated if needed. Each patient was given sufficient time to respond to encourage an accurate response for each question.

2.11 Statistical analysis

Data entry was completed in an Excel spreadsheet and analyzed using Statistical Package for the Social Science version 25.0 software (SPSS Inc., Chicago, IL, USA). Continuous variables were reported as mean ± standard deviation (SD) and analyzed using either an independent t-test or a Mann-Whitney test based on normality. Frequencies and percentages were used to describe dichotomous data, which were compared using the Chi-Square test or Fisher’s exact test. Repeated measures ANOVA assessed the time required to place sealants among the groups. Pearson’s correlation coefficient examined the link between age and time taken for the procedure. The sealant placement duration, by arch, gender and tooth type, was analyzed by independent t-tests. Differences in technique acceptance for each question were evaluated using a one-sample chi-square test. Finally, a mixed-effects logistic regression model, accounting for individual-level clustering, was employed to investigate the findings. The level of significance for all tests was set at p < 0.05.

3.1 PFS retention with follow-up time period

Table 2 demonstrates the comparative analysis of PFS retention with the follow-up time period between the two isolation groups. The majority of sealants were fully retained after 6 (79%), 12 (71.9%) and 18 (66.6%) months of sealant placement. CRI groups have slightly more retained PFS than the DS group at all follow-up periods (Table 2). However, the two groups had no statistically significant difference (p > 0.5). Both groups showed a statistically significant difference in retention rates between 6–12 and 6–18 months of analysis (p < 0.001).

3.2 Mixed-effects logistic regression

Table 3 illustrates the effectiveness of the two isolation techniques. Teeth isolated using the DS method had 1.63 times the odds of achieving complete retention at 6 months compared to those isolated using the CRI method (odds ratio (OR) = 1.63, 95% confidence interval (CI): 0.73–3.64) and 1 time the odds of having complete retention at 12 and 18 months when compared to CRI-isolated teeth (OR = 1.04, 95% CI: 0.51–2.13; OR = 1.02, 95% CI: 0.51–2.01). However, no significant difference was detected.

3.3 Placement time measurement

The overall time for sealant placement using each isolation technique was compared (Table 1). There was no significant difference in the time of sealant placement among the groups (p = 0.139). When the time for isolation was compared between the arches, the placement of sealants in teeth isolated with both systems took longer in the maxilla than in the mandible. However, this finding was insignificant between the study groups (p = 0.262). A negative correlation was seen for both types of isolation and age (DS = −0.072, CRI = −0.124). The placement time decreased as the children’s age increased. Although this association was stronger in the CRI group compared to the DS group, no statistical significance was documented (DS, p = 0.299; CRI, 0.523).

3.4 Participants’ acceptance

The participants were asked about specific acceptance parameters related to each type of isolation, and their responses were documented (Table 4, Fig. 1). The majority of participants (75%) reported that both isolation systems were comfortable during their use. Although 45% of the CRI group stated that the isolation uncomfortably stretched their mouth compared to those of the DS group (34%), the result was not significant (p = 0.362). On the other hand, around half of the DS group described that they tasted the material compared to a third of the CRI group. When asked about the feeling of gagging during the application, most participants in both groups (81%) positively agreed. Overall, there were no statistically significant differences in the participants’ responses between both groups.