The goal of this randomized clinical trial is to test the effect orally administration of Probiotics based on Lactobacillus rhamnosus LR04 and Lactobacillus plantarum LP14 as adjuvant in caries prevention in subjects who can not properly perform oral hygiene procedures. The main questions it aims to answer are:

• QUESTION 1: orally administered probiotics based on the previous strains could represent a useful tool in support of special needs patients in tooth decay prevention?
• QUESTION 2: orally administered probiotics based on the previous strains could ameliorate salivary pH management?

Partecipants in the test group will take the test probiotic for 90 days in adjunction of the routinary oral hygiene procedures.

Partecipants in the positive controlled group will take the placebo for 90 days in adjunction of the routinary oral hygiene procedures.

Partecipants in the negative control group will perform only the routinary oral hygiene procedures.

Researchers will compare 3 groups to see if orally administered probiotics based on L. rhamnosus and L. plantarum may help in the management of clinical status and salivary pH levels.

Recent literature has highlighted how patients' oral health is closely linked to the presence of intellectual and developmental disabilities (IDD). It has in fact been found that in patients with IDD the level of oral health tends to be lower than in subjects without IDD, and how this has an influence on the general state of health. A key role appears to be played by caregivers, who carry out the delicate task of maintaining an adequate level of oral hygiene. Among various aspects, daily oral hygiene maneuvers were considered as a key intervention in maintaining good health. In this regard, it is worth remembering that a study conducted in 1990 on caregivers demonstrated how, despite knowing the characteristics of the healthy appearance of the tissues supporting the dental elements, not everyone knew how this was closely related to the oral hygiene. Likewise, the study by Kilian and collaborators demonstrated how the maintenance of an oral microbiota that promotes oral health is not only desirable, but also possible. Given that the implementation of correct home hygiene represents a cornerstone in the management of general well-being, we decided to evaluate whether a formulation that allows the strengthening of bacterial populations competitive with respect to cariogenic populations could be significantly useful for the maintenance of these patients.

Inclusion criteria: adult and minor special needs patients belonging to the University Dental Clinic of Chieti. Presence of motor and/or cognitive difficulties in carrying out oral hygiene maneuvers at home.

Exclusion criteria: special needs patients with effective home hygiene.

Minimum sample size: Calculation of sample size (Alpha = 0.05; Power = 95%) for 3 independent study groups, and a continuous primary endpoint.

Sample size = Z2 (1-alpha/2) p (1-p) / d2 Where Z(1-alpha/2) is the standard variate corresponding to 1.96 at 5% type 1 error, p is the expected proportion in the population expressed in decimals based on previous studies and d is the confidence level decided by the researcher expressed in decimal. 20 patients are required per group, for a total of 60 patients. To these patients, the dropout percentage of 10% must be added, so the total is 70 patients.

BASELINE - T0. Signature of informed consent. Completion of a specific questionnaire regarding consumption of simple sugars and initial home oral hygiene procedures. Oral cavity inspection with registration of gingivitis according to dichotomous qualitative indices by quadrants.Recording of specific parameters: Salivary pH via GEASS® pH meter. DMFT (Decayed Missing Filled Teeth).

Random placement of the patient in the test, positive or negative control group.

TEST: instruction of the subject and/or caregiver in home oral hygiene 2/day + oeally administred probiotic based on L. plantarum and L. rhamnosus for 90 days.

POSITIVE CONTROL: instruction of the subject and/or caregiver in home oral hygiene 2/day + orally administred placebo.

NEGATIVE CONTROL: instruction of the subject and/or caregiver for home oral hygiene procedures 2/day.

T1 - AFTER 3 MONTHS FROM T0. Oral cavity inspection with recording of gingivitis according to dichotomous qualitative indices by quadrants. Recording of pH and DMFT.

Randomization. The treatment that is due to the individual patient is kept in sequentially numbered, opaque and sealed envelopes (SNOSE Sequentially Numbered, Opaque, Sealed Envelopes). The products used for both the test and the controls will be supplied in anonymous tubes so that neither the patient nor the investigator will be aware of them.

Statistical analysis: Developed by trusted bioinformatics group.

Inclusion Criteria:

• individuals with intellectual disability in presence of gingivitis in 1 quadrant at least and 1 decayed tooth at least, and improper oral hygiene routine.

Exclusion Criteria:

• individuals without intellectual disability or with the condition in absence of gingivitis, decayed teeth and improper oral hygiene routine.

A decision regarding IPD sharing has not been made yet because a dedicated website is not available at the momente.

SNOSE Sequentially Numbered, Opaque, Sealed Envelopes