This study is to evaluate the effect of angle of impaction, impaction depth, and bone density on surgical difficulty of impacted lower third molar, by measuring the angle of impaction, the depth of impaction (Winter's Red line), and bone density (gonial, and antegonial indices) preoperatively by using panoramic radiograph and to correlate the angle, the depth of impaction, and bone density with the surgical difficulty by operation time and surgical technique.

• All patients will provide detailed medical history and will sign a written informed consent. Oral hygiene instruction, scaling, and root planing.
• Panoramic radiograph will be taken for every patient, It will be used for measuring the angle of impaction along the lamina dura of the lower second and third molar and measuring impaction depth (Winter's Red line) by using software (planmeca romexis). The same software will be used to measure gonial index and antegonial angle as indices of bone density.
• All patients will have mouth rinsing with 0.2% chlorhexidine digluconate for 1 minute.

Surgical Procedure

• After administration of local anesthesia, full thickness enveloped or triangular flap incision according to the surgical principles.
• Flap reflection with periosteal elevator and retraction.
• Bone removal (if required) by using a slow speed, high torque surgical handpiece with sharp bur with copious normal saline irrigation.
• Tooth sectioning (if required) by using sharp diamond bur with saline irrigation.
• Tooth extraction by using appropriate elevator. .The operative difficulty will be determined by the surgical techniques of the extraction and the duration of extraction. With respect to the surgical technique the degree of difficulty is considered low when the extraction is performed by elevator alone, moderate when bone removal (ostectomy) is required, and high when ostectomy and tooth sectioning is required for tooth extraction.

For the duration of surgery, the difficulty is considered low when the duration of surgical extraction is less than 15 minutes, moderate when the duration is 15-30 minutes, and high when the duration is more than 30 minutes.

• Irrigation and cleaning of surgical site and removing remaining follicle if present.
• Bone smoothing with bone file and irrigation with saline.
• Flap Suturing with black silk suture 3/0.
• Ask the patient to bite on wet gauze.
• Instruction and medication (analgesic and antibiotic if required).

Inclusion Criteria:

1. Healthy patients over 18 years old of either gender.
2. Patients who have mesioangular or horizontal impacted mandibular third molar.
3. Presence of mandibular second molar.
4. Ability to tolerate surgical procedure.

Exclusion Criteria:1. Patients with vertically and distoangularlly impacted teeth.

2. Patients with uncontrolled systemic diseases. 3. Patients with history of chemotherapy or radiotherapy therapy to the head and neck region.

4. Acute infection at the surgical site at time of operation. 5. The presence of cysts or tumors associated with the impacted teeth.

This study will include a minimum of 50 patients indicated for surgical removal of impacted mandibular third molars at Baghdad college of dentistry.

all the results