Post Extraction Changes After Ridge Preservation Using Allogeneic Dentin Matrix Vs Demineralized Freeze Dried Allograft

This study aims to evaluate clinical, radiographic and histomorphometrical differences between using Allogenic Demineralized Dentin matrix versus Demineralized Freeze-Dried Bone Allograft (DFDBA) in alveolar ridge preservation after tooth extraction in the esthetic zone.

Research Procedure in brief:

The study is to be conducted in the Oral Medicine and Periodontology department, Faculty of Dentistry- Cairo University, Egypt.Patients are to be selected from the outpatient clinic of the department of Oral Medicine and Periodontology, clinic of the department of Oral surgery and clinic of the department of Endodontics -Cairo University.

The initial therapy consists of periodontal treatment (phase I therapy) including supragingival scaling, subgingival debridement if needed, adjustment of faulty restoration and polishing. The mechanical plaque control instructions for each patient include brushing and interdental cleaning techniques.

surgical interventions: Atraumatic extraction.The patient will rinse their mouth with 0.12% Chlorhexidine Administration of 4% articaine hydrochloride with 1:100,000 epinephrine will be as local anesthetic agent.Flapless and atraumatic tooth extraction will be initiated, using 15C blade intrasulcular incision will be performed.A periotome will be utilized to sever the periodontal ligament (PDL) fibers, followed by extraction witha straight elevator and extraction forceps.

Test group:

preparation of Allogenic Demineralized Dentin Matrix. Extracted teeth will be collected from the Departments of oral maxillofacial surgery and periodontics, Cairo university. Cleaning the teeth from any caries, Filings, cement, tartar, soft tissue debris and prosthetic components will be performed using a diamond bur under abundant irrigation with physiological water. Then it will be proceeded to the following steps

1. (Washing with Distilled water for 30-120 mins) The dental root that has had its soft and pulp tissues removed is cleaned with distilled water for anywhere between 30 minutes and two hours. The dental root includes residual dentin and cementum, even though soft and pulp tissues have been removed.
2. (Quick Freezing with liquid nitrogen -160 o C for 30-120 mins Then Grinding to particle size of 300- 800 μm) The dental root is processed into powder by quick-freezing and crushing, the same method used for the dental crown, with an average particle diameter of 200 mm to 1,500 mm. To eliminate impurities and remaining soft tissue, the powder will be washed with distilled water for 30 minutes to 2 hours.
3. (Ultrasonic Cleaning cycles, 1st with Distilled water for 5-10 mins, 2nd with 5-7% Hydrogen Perioxide10-30 mins then 3rd with Distilled water for 5-10 mins at 60-80 o) Each cycle of ultrasonic cleaning includes: a first washing step in which the powder is processed with ultrasonic cleaning for about 5 minutes to about 10 minutes in pure water or sterilized distilled water; a second washing step in which the powder is processed with ultrasonic cleaning for about 10 minutes to about 30 minutes in hydrogen peroxide solution; and a third washing step in which the powder is processed with ultrasonic cleaning for about 10 minutes to about 30 minutes in hydrogen peroxide solution. The concentration of the hydrogen peroxide solution is around 5% to 7%, the volume of the washing fluid of each washing step is approximately 5 times to approximately 10 times that of the powder, and the temperature of the washing fluid may be approximately 60°C to 80°C.
4. (Defatting with Chloroform Methanol Solution1:0.5 for 3-12 hours) The powder cleaned in the preceding step can be largely degreased using a chloroform methanol solution with a chloroform to methanol weight ratio of about 1:0.5 to about 1:2 for 3 to 12 hours. The largely degreased powder can be centrifuged to remove floating fat and rinsed with distilled water for at least 1 hour.
5. (Demineralization with0.5N HCL for 10-60 mins) For about 10 minutes to about 1 hour, the principally degreased powder is delimed (Demineralized) with about 0.5N hydrochloric acid aqueous solution whose volume is about 5 times to about 10 times that of the powder.
6. (Dehydration with Neutral Ethyl Alcohol for 30 mins then Defatting with Chloroform Methanol Solution 1:0.5 for 3-12 hours) The delimed powder is next dehydrated with neutral ethyl alcohol for 30 minutes to 2 hours. The dehydrated powder can be secondary degreased using a chloroform methanol solution with a chloroform to methanol weight ratio of approximately 1:0.5 to about 1:2 for 3 to 12 hours.
7. (Washing with Normal Saline \& Freeze Drying then Sterilization using Ethylene oxide gas) The above-mentioned powder is degreased, delimed, and dehydrated before being post-treated with the steps of washing with normal saline solution and freeze-drying the degreased, delimed, and dehydrated powder; and sterilization will be done using ethylene oxide gas.

Alveolar ridge preservation:

• Following extraction, curettes will be used to remove granulation tissues, and the socket will be irrigated with sterile normal saline.
• Then the socket will be filled either with Allogeneic Dentin Matrix or Demineralized freeze-dried bone allograft (DFDBA) in control group up to the crestal level of then bone followed by placement of a collagen membrane to cover the socket. Suturing technique will be a criss-cross horizontal mattress to ensure that most of the grafting material is covered.

Postoperative Care and follow up:

• Participants will be instructed to avoid causing any damage to the operated site, to prevent interfering with the sutures, and to avoid consuming hot meals or vigorous rinsing.
• They will be encouraged to continue cleaning their teeth, only avoiding the operated site. Moderate tooth brushing for the operation site will be recommended after two weeks.
• Participants will be given Amoxicillin 500 mg three times a day for seven days, or doxycycline 100 mg twice a day if they are penicillin sensitive.
• Ibuprofen 600 mg will be provided for severe pain.
• Participants will be asked to use a 0.12% Chlorhexidine mouthwash twice daily for two weeks to assist gentle rinsing.
• Sutures will be removed two weeks after the surgery.
• A baseline cone-beam computed tomography (CBCT) scan will be conducted on the same day postoperative. A final follow-up visits and CBCT scan will be scheduled for six months postoperative to evaluate the dimensions of the alveolus before implant placement.

Biopsy collection After a 6-months healing period, a biopsy will be collected from the central area of the grafted site with a 3- mm trephine bur at the time of implant implantation. The biopsy will be immediately fixed in 10% neutral buffered formalin, followed by dehydration in a series of increasing concentration alcohol baths (varying from 50% to 100%). The specimen will then be encased in paraffin. Finally, a 4 m thick tissue section will be cut and stained with hematoxylin and eosin for subsequent histological investigation.