During the study, designated pressure points before and after one month of splint usage will be evaluated as possible indicators of two different splints efficacy..

Two study groups will be formed. The study will be conducted on patients reporting to the Dental Prosthetics Outpatient Clinic of PUM in Szczecin, Poland. Patients aged 18-65 years with probable bruxism, yet requiring splint therapy will be included in the study.

During the study, designated pressure points before and after one month of splint usage will be evaluated as possible indicators of two different splints efficacy..

Two study groups will be formed. The study will be conducted on patients reporting to the Dental Prosthetics Outpatient Clinic of PUM in Szczecin, Poland. Patients aged 18-65 years with probable bruxism, yet requiring splint therapy will be included in the study. Probable bruxism will be diagnosed on the basis of the patient's history and examination as follows. Inclusion criteria:

I. Nocturnal Bruxism according to International Classification of Sleep Disorders, Second Edition (ICSD-2).

A. The patient reports or is aware of tooth-grinding sounds or tooth clenching during sleep.

B. One or more of the following is present: a. Abnormal wear of teeth b. Jaw muscle discomfort, fatigue, or pain and jaw lock upon awakening. c. Masseter muscle hypertrophy upon voluntary forceful clenching.

C. The jaw muscle activity is not better explained by another current sleep disorder, medical or neurological disorder, medication use, or substance use disorder.

II. Additional questionnaire for detecting bruxers:

1. Has anyone heard you grinding your teeth at night?
2. Is your jaw ever fatigued or sore in the morning?
3. Are your teeth or gums ever sore on awakening in the morning?
4. Do you ever experience temporal headaches on awakening in the morning?
5. Are you aware of grinding your teeth during the day?
6. Are you ever aware of clenching your teeth during the day
7. Can you imitate a sound of grinding using your teeth.

III. Eligible patients will be randomly assigned into two groups. Sealed, opaque envelopes will be used for randomization. The first group will be treated with a stabilization appliance described by Okeson. The second group will undergo therapy with a two-jaw splint with an arch. Patients will be informed about how to use and maintain hygiene of the splint. It will be recommended to use a splint only while sleeping.

IV. Pressure pain threshold test (PPT) will be carried out at the Department of Prosthodontics of the Pomeranian Medical University, Szczecin, Poland using the Wagner Paintest FPX 25 algometer. Points within the following muscles will be examined:

masseter muscles, anterior, middle and posterior abdomens of the temporal muscles, a point at the height of the TMJ larger exterior convexity, the sternocleidomastoid muscles and the preauriculare point, bilaterally two measurements at each visit. The test will be performed at the first visit and after 30 days of therapy.

The algometer comes with a 1 cm2 rubber tip, which measures the pressure in kg / s while pressing on the tested surface. Both test results will be used as a pre- and post- treatment evaluation.

Inclusion Criteria:

• I. Nocturnal Bruxism according to International Classification of Sleep Disorders, Second Edition (ICSD-2).

A. The patient reports or is aware of tooth-grinding sounds or tooth clenching during sleep.

B. One or more of the following is present: a. Abnormal wear of teeth b. Jaw muscle discomfort, fatigue, or pain and jaw lock upon awakening. c. Masseter muscle hypertrophy upon voluntary forceful clenching.

C. The jaw muscle activity is not better explained by another current sleep disorder, medical or neurological disorder, medication use, or substance use disorder.

II. Additional questionnaire for detecting bruxers:

Has anyone heard you grinding your teeth at night? Is your jaw ever fatigued or sore in the morning? Are your teeth or gums ever sore on awakening in the morning? Do you ever experience temporal headaches on awakening in the morning? Are you aware of grinding your teeth during the day? Are you ever aware of clenching your teeth during the day Can you imitate a sound of grinding using your teeth.

Exclusion Criteria:

• unrestored tooth losses
• patients wearing removable dentures of any kind
• psychiatric conditions undermining/preventing occlusal splint usage