This prospective randomized controlled trial will aim to evaluate the effectiveness of two methods of delivering oral hygiene instruction to children aged 3 - 6 years: parent-modeled toothbrushing (control) and the MoodBrush digital application (experimental). The primary endpoint is the change in plaque index scores before and after brushing, measured on 12 tooth surfaces using the Silness and Loe Plaque Index. The study rationale is based in the need to identify efficient and engaging strategies to improve pediatric oral hygiene. The expected outcome is that both groups will demonstrate significant reductions in plaque scores, with children using MoodBrush achieving similar, if not greater improvements in plaque index scores. Follow-up includes an immediate post-brushing assessment at the dental visit, with intrarater reliability checks to ensure measurement consistency. Statistical analyses will include paired t-tests to evaluate pre-post changes within groups and two-sample t-tests to compare differences between groups, with significance set at p < 0.05. A sample size of 112 participants provides 80% power to detect a mean difference of 0.30 in plaque index score reduction.

This study is a prospective randomized control trial. The study will be conducted at the Altamed Clinic (Sunflower location) and the University of Southern California Advanced Pediatric Dental Clinic. Established patients of record that are 3-6 years old who meet inclusion criteria will qualify. A recruitment script will be used to recruit patients into the study. If parents of patients agree to participate in the study, they will sign all informed consents.

Participants will be randomly assigned to two groups by block randomization and having pre-assigned envelopes in numeric order for each participant. The envelopes will then be stored in a folder; once a participant consents to enroll in the study, the envelope will be drawn in numeric order determining the participants group to ensure it is randomized. The control group will be provided oral hygiene instructions in the form of modeling brushing with a parent or caretaker. The experimental group will be provided oral hygiene instructions in the form of a phone application called "MoodBrush" to teach children how to properly brush.

MoodBrush is a helpful app that aids in teaching children how to brush their teeth. The application uses bright colors and graphics to show children where to brush their teeth and has a timer for each quadrant to ensure equal brushing time for each portion of the teeth (Appendix I). MoodBrush is free to download has no in app purchases that will be made during study and is compatible with Apple devices. Parents will not need to download app for participation in this study.

No intervention monitoring will be needed for this study. Principal investigator will be present during all procedures to ensure study is conducted in appropriate manner. Completion of parent survey will serve as record for study participation.

The study will follow a series of systematic steps within standard of care as well as additional steps as part of the study design.

These steps will include: Parent survey (study design), dental exam (standard of care), initial plaque score recorded through visual examination of teeth using intraoral mirror and dental explorer (study design), brushing intervention either part of control or experimental group (study design), post brushing plaque score recorded through visual examination of teeth using intraoral mirror and dental explorer (study design), dental cleaning (standard of care), nutritional counseling (standard of care), oral hygiene instructions (standard of care), and fluoride varnish (standard of care).

3.1 Control Group: Parent of patient will receive a brief survey to assess their oral health education level including their current oral hygiene practices at home. Documentation of plaque index of patient will be done using the Silness and Loe Plaque Index scoring 0-3 on 12 teeth surfaces. Surfaces of teeth will be evaluated using visual examination using intraoral mirror and dental explorer. The surfaces will include #A buccal and lingual, #E buccal and lingual, #J buccal and lingual, #K buccal and lingual, #O buccal and lingual, #T buccal and lingual. Parent and child will then brush their teeth together for two minutes with observation by dental team. Parent and child will be provided toothbrush and will be asked to model proper brushing technique for their child as they would instruct at home. A timer will be set for two minutes to aid in brushing instruction. New plaque score of the child will be taken and recorded after brushing

In the parent modeled brushing group, parents will be expected to provide brushing instructions along side their child while brushing with them for 2 minutes. No additional data will be collected from their parent. No plaque scores for parent will be recorded. Parents will be required to take parent survey for this group.

3.2 Experimental Group: Parent of patient will receive a brief survey to assess their oral health education level including their current oral hygiene practices at home. Documentation of plaque index of the patient will be done using the Silness and Loe Plaque Index scoring 0-3 on 12 teeth surfaces. Surfaces of teeth will be evaluated using visual examination using intraoral mirror and dental explorer. The surfaces will include #A buccal and lingual, #E buccal and lingual, #J buccal and lingual, #K buccal and lingual, #O buccal and lingual, #T buccal and lingual. Parent and child will be present for the visualization of MoodBrush tooth brushing phone application and participant will brush along with instruction provided by the application for two minutes with visual application instruction of 30 seconds per quadrant. The phone application will be present on a tablet in the dental clinic, the patient does not need to download the phone application on their personal device. New plaque score will be taken and recorded after brushing.

For the phone application modeled brushing, parents will not be expected to participate in the brushing intervention portion. Parents will only be required to take the parent survey for this group.

Plaque index will be obtained by one provider. Intrarater reliability will be evaluated to ensure consistency.

Participants will only have data collected during one recall dental appointment. All information will be collected on that day and patients will not need to return for follow up in regards to this study. No parent log will be needed due to no continued monitoring for the purpose of this study.

Inclusion Criteria:

• ASA I or II
• children aged 3-6 years presenting for recall dental visit at AltaMed (Sunflower) clinic or USC Advanced Pediatric Dental Clinic
• must speak English or Spanish, Frankl 3 or 4.

Exclusion Criteria:

• Physical limitations that would prevent adequate oral hygiene
• Extensive caries preventing accurate readings on plaque index,
• Teeth needed for plaque score have not fully erupted or missing
• If behavior prevents them from cooperating for exam and toothbrushing
• Inability to brush for full two minutes.