Prevention of dental problems by controlling plaque is the best solution to maintain oral health and prevent high cost of dental treatments. Home oral care is the cornerstone in removing plaque and therefore controlling tooth decay and gum disease. Unfortunately, complete plaque removal is difficult to achieve by mechanical methods alone.

For effective plaque control antiplaque agents such as chlorhexidine mouthwash is necessary. Chlorhexidine has shown distinct advantage, but it has many side effects such as staining of the teeth and the tongue, altered taste sensation, and increased calculus formation often deters its use for long periods.

Recently the use of herbal mouthwashes is rising due to the widespread awareness that natural substances have less side effects and lower economic cost. Of various plant extracts used as a base for mouthwashes, aloe vera deserves a special attention as it has recently been introduced in dentistry after years of use in medicine field.

Many recent studies stated that aloe vera mouthwashes has shown efficiency in plaque control and prevention of gingivitis, but there is a need for more studies to determine the best protocols regarding concentration and frequency of its use. A review of the literature shows that there is no randomized controlled trials evaluating its efficiency in plaque control and prevention of gingivitis in children, which is the main purpose of this study.

The crossover design will be adopted in this study, i.e. the three types of mouthwashes (experimental "aloe Vera", positive control "chlorhexidine", negative control "placebo") will be utilized for all participants, with an equal (5) days application period for each type of mouthwashes and a wash-out period of (12) days between each type to ensure the elimination of the effects of a mouthwash before moving to the next one.

The evaluation areas selected for the study comprised the central maxillary incisors and the first maxillary molars.

A special plaque guard will be fabricated to cover the evaluated teeth and their gingival margins, this plaque guard will prevent plaque removal of the evaluated teeth and facilitate localized plaque accumulation and the resultant gingivitis if any.

At the start of the study, all participants will be instructed on how to brush their teeth properly and continue their regular oral hygiene.

All subjects will be instructed to wear the plaque guards every time they cleaned their teeth, so that they will not brush the maxillary incisors and the maxillary first molars. This phase "the accumulation phase" will last for 3 days, and then the subjects will be recalled to assess the difference in plaque accumulation on the 5th day.

The following indices will be studied: Plaque index (PI) to assess the plaque accumulation, gingival index (MGI),and bleeding index (BI)to assess gingivitis. These indices will be recorded at the first and in the 3th day. The "rinsing phase" will begin from the morning of day 4 and last for 5 days.

15 ml of rinsing solution will be given to each subject who is not aware of what type of mouthwash he/she is receiving. Along with each bottle of mouthwash, a 10 ml syringe will be used to facilitate determining correct dosage. The subjects will be asked to rinse with 15 ml of the solution for 1 min, once daily. Intake of food and/or drinks will not be allowed for 2 hours after rinsing. The subjects will be recalled for evaluation of plaque accumulation once the "rinsing phase" is completed on 8th day.

Inclusion Criteria:

1. Patient ages between (8 - 12) years.
2. Healthy children without any systemic medical conditions.
3. Good oral health (no manifestations of oral diseases on the mucous membranes).
4. The presence of the maxillary first permanent molars and the maxillary central incisors.
5. No caries on the buccal and lingual surfaces of the teeth.
6. Cooperative children (positive or definitely positive on Frankl's behavior rating scale).
7. The patient has the physiological ability to use the mouthwashes, This will be confirmed by asking the child's parent first and then test his/her ability to rinse with water before being enrolled in the study.

Exclusion Criteria:

1. Children with systemic medical conditions.
2. Patients undergoing current dental or orthodontic treatment.
3. Patients who used any other mouthwash during the study period or were given antibiotic therapy within 2 weeks before starting the study or corticosteroids within 30 days before starting the study.
4. Patients who use removable prosthetic or orthodontic appliances.
5. Patients who have gingival pockets more than (3) mm or advanced gingival diseases.
6. Fluorescent patients.
7. Patients who have a sensitivity story for any element of the mouthwashes used in the study.
8. Patients who underwent an extraction within two weeks of starting the study.
9. Patient lack of commitment toward follow-up appointments.