Placing an implant immediately into a fresh extraction socket neutralizes the waiting time of six to eight months. There is less burden on the patient because drilling is reduced to a minimum. The combination of a screw implant and a bone graft is still needed to fill the gap between the implant and the socket because most types of implants were designed to be placed into healed alveolar ridges. The bone graft provides the following:

1. an increased initial stability to the implant, which is placed 2 to 5 mm apically into the socket;
2. a wider bucco-lingual (or -palatal) diameter around the neck of the implant where the forces are greater; and
3. prevention of any soft tissue ingrowth and, thus, potential loss of the implant.

The materials of choice for replacement therapy are single-stage implants (ITI [Straumann]) and composite polymers (Bioplant HTR [Bioplant Inc., South Norwalk, CT]) because one of the aims is to have predictable results and success in the simplest way.
The ITI system (Straumann) has been used successfully and clinically documented since 1974. ITI implants (Straumann) are all made of commercially pure titanium grade 4 (ISO 5832/11). The endosseous portion has a microporous titanium plasma coating with a roughness and thickness of approximately 20 mm and increases the area for bone apposition. The supracrestal cervical portion (neck) is cup-shaped (diameter, 4.8 mm) with a height of 2.8 mm and has a smooth machined surface to facilitate tissue management. An 8-degree morse taper connection is used with the whole range of titanium abutments, creating a friction fit connection and a micro-gap of less than 10 mm. The types of implants are hollow cylinder, hollow screw, and solid screw. All have a diameter of 4.1 mm and lengths varying between 8 mm, 10 mm, 12 mm, and 14 mm.
Bioplant HTR Synthetic Bone allograft (Bioplant Inc.) is a chemical mixture of porous polymethylmethacrylate spheres coated with polyhydroxylethylmethacrylate and an outer layer of calcium hydroxide carbonate graft. It is non-resorbable, hydrophilic, and microporous (opening, 250–350 mm). The granules average in size from 550/550 mm (HTR-40) to 700/750 mm (HTR-24) (Figs. 6 and 7). With a negative surface charge of 210 mV, it was shown first in animal experiments12– 13 and later in clinical studies14– 21 that it is a suitable material for bone replacement in general trauma treatment and oral surgery. The material does not require a barrier membrane19,20,22 and has substantial compressive strength up to 1800 psi. It possess several unique properties that are thought to be the result of the negative surface charge of 210 mV:

1. no epithelial ingrowth (no need to use any type of membrane);
2. no migration;
3. ease of handling and contouring; and
4. no colonization by bacteria.

Therefore, it not only adheres to surrounding bone but also to metal, such as titanium.
Dr. R. Becker (University of Syracuse) and Dr. R. Salkind (Rutgers University) showed that a negative charge between 28 mV and 212 mV facilitates and enhances bone healing and formation. Studies on salamanders proved that those animals use such extremely weak currents to regenerate lost body parts. Used in bone diseases (eg, osteomyelitis), the same negative charge provides complete healing.

The Procedures.
Hopeless teeth were extracted in 147 patients between 19 and 71 years of age, and a total of 556 ITI (Straumann) single stage screw implants (162 hollow screws and 394 solid screws, Ø 4.1 mm) were placed immediately 2 mm to 5 mm apically into the extraction sockets. Bioplant HTR-24 and HTR-40 (Bioplant Inc.) previously wetted with the marrow bleeding obtained from the drilling were packed firmly into the void between bone and implants. Primary closure was done with Vicryl (Ethicon Inc., Somerville, New Jersey) Rapid 2/0 or 3/0 for suturing the flap(s) and Vicryl Normal 4/0 around the neck of the implants. Prosthetic rehabilitation was done three to six months postoperatively and was obtained by placement of ball retained overdentures, implant cemented bridges, implant-tooth cemented bridges, or single crown.
Notice that patient selection was not done according to the standard selection criteria because the aim was to treat any patient, including those with alcohol, drug, or nicotine abuse, blood coagulation disorders, endocrine illnesses, poor oral hygiene, etc. The only contraindications were patients requiring chemotherapy and patients with psychotic illnesses. Also, it must be stated that most ball retained overdentures in the maxilla were placed on only two implants and not on the customary four implants. Four implants are most widely recommended in the literature, but because a ball-retained overdenture is soft tissue supported, the idea was that there would be no difference between upper and lower success rates if the osseointegration of the implants were accomplished. Four implants in the maxilla were only used in cases where the mandibular natural teeth could act as good and healthy antagonists.