In this randomized clinical study, we aim to evaluate the effects of Teethmate Desensitizer on postoperative sensitivity when applied underneath the composite restoration by comparing it with the negative control group.

For the purpose of statistical preliminary analysis, the part related to the comparison of the dependent two sample means (t test) was used in the G * power 3.1 program. The power of the test was taken as 90%, margin of error 5% and effect size 0.50. The total sample size was found to be 44. In this study, the required number of participants was determined to be at least 44, since the split-mouth technique in which both the experimental and the control groups will be used in each patient, and the number of participants to be included in the study was determined as 50 considering the ''drop-outs'' that may occur during the study. Then, randomization will be achieved using the blocked randomization technique. Randomization will be done on www.sealedenvelope.com website. For blocked randomization, the seed number will be 12345 and the block width will be 2.

After applying to Başkent University Faculty of Dentistry, dental caries are detected as a result of the clinical and radiological examination, and female or male patients will be selected among the ones who are referred to the Restorative Dentistry Department's clinic for treatment. Participation in the study is on a voluntary basis and the participants who accept the invitation will have the Informed Consent Form read and signed. If deemed necessary, the participants will be given oral hygiene motivation and initiatives will be started after their oral hygiene is achieved to a satisfactory level.

Before starting treatment of individuals diagnosed with caries clinically and radiologically, the vitality of the relevant teeth will be measured using a vitalometer (Model D624, Parkell Inc, USA). After the opening of 2 cavities in each participant, the cavities will be isolated, and Teethmate Desensitizer will be applied randomly to one of the two cavities. In order to ensure randomization, the randomization list prepared using the program on www.sealedenvelop.com will be put in an opaque envelope. When the application will be made, the envelope will be opened. Then, CaOH(Dycal, Dentsply, USA) will be placed in the deepest place where the pulp is closest. Restorations will be performed after the matrix system is applied when necessary. All cavities one-step self-etch an adhesive (Clearfil SE Bond, Kuraray Noritake, Tokyo, Japan) LED light applied according to the user instructions (Ledmax Cordless 550 Benlioğlu, Turkey)> 1,500mw / cm2 for 10 seconds polymerized. The teeth will be restored using an oblique incremental technique with a composite resin (Filtek Z250, 3M Espe, USA). Each layer will be polymerized for 20 sec. Finishing and polishing process will be done using diamond finishing burs, tires and polishing discs (Soflex, 3M Espe, USA). Restoration will be done by a single operator (LK). After the restoration, patients will be given two forms, one for each tooth, where they will record their daily pain levels for a week, and how to register on this form will be explained. These forms given to the participants will include a Numerical Rating Scale (NRS) with scores between 0-4 and a Visual Analogue Scale (VAS) of 0-100mm for 1 week. When patients will be called to the control appointment after a week, the forms in which they score the sensitivity level will be taken back. 6 weeks after the restorations are applied, the patients will be invited to a control appointment and the restorations will be checked. At the first week and sixth week control appointments, the restorations will be evaluated by another physician (KY). At the end of the 6 week, the vitality will be controlled. During the six-week study, patients will be asked not to use any pain medication, and if the participant uses painkillers during the study, the participant will be excluded from the study.

Inclusion Criteria:

1. Accepting to participate
2. Being in the age range of 18-65
3. Presence of at least 12 teeth in occlusion
4. The teeth to be included in the study have natural opposite and aproximal teeth
5. The teeth to be included in the study will be vital
6. The anterior or posterior teeth to be included in the study, regardless of the deep carious cavity type, have a primary carious lesion that is estimated to be very close to the pulp during cavity preparation but the pulp will not expose (dentin thickness close to the remaining pulp is less than 2 mm)
7. In the patient's mouth, one on the right and the other on the left 4., 5. and 6. 2 teeth matching the criteria.

Exclusion Criteria:

• Not accepting voluntarily to participate in the study 2- Being younger than 18 years old or over 65 years old 3- Presence of spontaneous toothache or orofacial pain 4- Bruxism 5- Presence of advanced periodontal disease 6- The presence of a serious systemic disease. 7- Worn, cracked or devital teeth with enough material loss to be crowned 8- Presence of lesions in the apical region after radiographic examination 9- Exposure of pulp during cavity preparation 10- Presence of gingival recession 11- Individuals who have taken painkillers, anti-inflammatory and psychotropics in the last two weeks and are currently taking 12- Pregnancy and breastfeeding individuals 13- Individuals who are allergic to the materials to be used

The baseline analysis included participants whose treated teeth responded positively to the electric pulp test. Each participant was examined intraorally using an electric pulp tester, and only teeth that responded to the vitality test were considered vital and included in the study.

Up to 7 days and 6 weeks after restorative procedure

Participants were actively and systematically monitored for any adverse events, including temporary sensitivity, discomfort, or soft tissue irritation, during treatment and at follow-up visits after the restorative procedures.

Of the 50 total participants, 49 attended the 1-week and 47 attended the 6-week follow-up. No non-serious adverse events were reported or observed during the study period.