Evaluation of the muscle activity of masseter in tooth borne partial denture wearers (class III modification 1 Kennedy's classification) with two different denture base materials (Breflex and PEEK) by means of electromyograph.

Inclusion Criteria:

• All patients must have Kennedy class III modification I upper partially edentulous ridges.
• The remaining teeth have good periodontal condition, with no signs of attrition or gingival recession.
• All patients have skeletal Angle's class I maxillo-mandibular relationship and have sufficient interarch distance.
• Free from any systemic or neuromuscular disorder that might affect chewing efficiency of masticatory muscles.
• Free from any tempro-mandibular joint disorder.
• The patients have good oral hygiene and low caries index.

Exclusion Criteria:

• Patients having abnormal habits as bruxism or clenching.
• Patients having hormonal disorders as diabetes, thyroid or parathyroid hormonal diseases were not included.
• Teeth with compromised bone support.
• Patient with xerostomia or excessive salivation.
• Patient with abnormal tongue behavior and/or size.

Only statistician will be blinded as the 2 materials have different colors The patients: they won't be aware of the lab procedures till finishing and delivery of the dentures.

The outcome assessor: the assessor who will assess the muscular activity will be blinded.