What immediate dental implantation means, its advantages and disadvantages, and an explanation of whether bone grafting repair is needed

Implant restoration is a new trend in repairing dentition defects. As patients' demand for oral health increases, immediate restoration has also received more and more attention.

Advantages of immediate implantation:

Immediate implantation can shorten the patient's treatment time. Usually, delayed implantation requires implantation 3 months after tooth extraction, whereas immediate implantation involves performing the implant surgery immediately after extracting the affected tooth, thus shortening the treatment time by 3 months and allowing the patient's chewing function to be restored as quickly as possible. At the same time, immediate implantation performs tooth extraction and implant surgery at the same time, reducing one surgery compared with delayed implantation and lowering the patient's pain. In addition, one of the most important advantages of immediate implantation is that it can reducealveolar boneresorption and maintain alveolar bone height. In delayed implantation, during the healing process of the remaining alveolar socket after tooth extraction, partial resorption of the surrounding alveolus will occur, and in later implantation, the preparation of the implant socket will also grind away a certain amount of bone. Immediate implantation prepares the implant socket on the basis of the alveolar socket, which can save bone grinding and reduce resorption of the alveolar bone around the extraction socket; therefore, it can better maintain the height of the alveolar ridge.

However, it should be noted that immediate implantation has more complex operative key points than delayed implantation, and every step of the implant procedure needs to be strictly carried out.

Important factors affecting the success of immediate implantation:

(1) Strictly control indications:

The indications for immediate implantation are: traumatic tooth loss with a small amount of bone loss; badly damaged teeth with root fracture that need extraction; teeth with dental disease that cannot be treated; periodontal disease teeth with severe periodontal bone loss and no suppurative discharge; healthy surrounding soft tissue with enough periosteum available for use; systemic diseases without surgical contraindications. For patients with relatively severe periodontal disease or periapical inflammation, such as those with periodontal pockets or suppurative discharge from adjacent soft tissue, periapical abscess, relatively large granuloma or cyst, suppurative discharge from the wound may occur during tooth extraction, or there may be insufficient bone support. If the wound is close to unfavorable positions such as the mandibular nerve canal, maxillary sinus, or nostril, which may cause injury during implantation, then immediate implantation is not suitable. For those with systemic diseases, which may affect healing of the implant wound, immediate implantation should also not be used.

(2) Reduce intraoperative tooth extraction trauma.

During the tooth extraction process, the alveolar bone at the interdental septum and the integrity of the alveolar bone wall around the extraction socket should be preserved as much as possible, avoiding fracture, and minimally invasive tooth extraction is advocated. During the tooth extraction process, once fracture of the bone wall occurs, it will affect the decrease in early implant support, while tissue tearing will cause the wound healing time to be too long, making infection and incomplete wound closure prone to occur.

(3) Prevent intraoperative and postoperative infection.

Infection is another important factor leading to implant failure. Prevention of infection is divided into two aspects: removal of infectious material from the extraction wound during surgery, and control of wound infection after surgery. For some molars with necrotic pulp that have not undergone thorough root canal treatment, there will inevitably be varying degrees of infection around the apex, and after tooth extraction there will be residual infection in the alveolar socket. Therefore, thorough curettage must be performed to clean the infected alveolar socket. After surgery, antibiotics should be used locally and systemically according to the patient's overall condition and wound size to prevent infection. If infection occurs, it will inevitably affect the combination of the implant body and alveolar bone, leading to implant failure.

Immediate implantation surgery:

1 Preoperative preparation:

Routine dental radiographs should be taken to understand the local bone tissue condition and the condition of adjacent tissues. For the premolar or molar region, panoramic tomography should be taken to observe the position of the maxillary sinus and inferior alveolar nerve canal and to measure the bone volume between the tooth roots.

2 Tooth extraction:

(1) Principle one of atraumatic tooth root extraction: bone defects around the implant are the main reason affecting the implant's ability to obtain primary stability.

(2) Therefore, during tooth extraction, care should be taken to prevent alveolar bone injury and fracture, and forceps extraction should be used as much as possible. Multi-rooted teeth should be separated by root, and extraction should be performed using mesiodistal dislocation force. (2) Scrape clean the residual periodontal ligament: after tooth extraction, carefully check whether there is residual soft tissue in the wound. If there is, a curette must be used to carefully curette and remove all residual periodontal ligament.

3 Implant bed preparation:

First use a guide drill to deepen the extraction wound, then use a series of widening drills to gradually enlarge the implant bed from thin to thick, preparing an implant bed of appropriate size and depth. Generally, the depth of the implant bed should allow the implant root to be placed 3-5 mm into the bone. Effectively preventing and reducing thermal damage to the alveolar bone in the implant area during implant bed preparation is the key to successful implantation. Bone tissue is very sensitive to thermal damage. Intravital microscopy has found that bone tissue damage occurs after heating at 50°C for 1 min, and experiments have proven that the thermal tolerance threshold of bone tissue is 47°C.

To prevent bone tissue thermal damage as much as possible during the preparation process, the following measures should be taken: 1) The drill bit should be sharp, and drilling should proceed from small to large, increasing by 0.2 mm each time. 2) Drilling pressure should be light, usually using an up-and-down lifting method. 3) Drilling speed should be low, <800 rpm. 4) Cooling water should be used reasonably. When the implant bed preparation is relatively deep, external irrigation with normal saline cannot achieve cooling of the deep wound surface, so intermittent stopping is often used; after withdrawing the drill bit, normal saline is used for direct irrigation. This can not only lower the temperature but also flush out deep bone debris. An internal cooling device can also be used. In addition, the drill bit should be kept close to the palatal bone wall within the alveolar socket and parallel to the long axis of the adjacent teeth [7], to prevent lateral perforation of the labial bone wall.

4 Implant placement:

Use normal saline to rinse away bone debris in the implant bed, then place the implant, with its top flush with the alveolar ridge crest or slightly lower than the alveolar ridge crest by 1-2 mm. For the extraction wound of multi-rooted teeth, because the buccal bone wall is thin and deviates too much to the outside, the implant is generally placed in the alveolar socket of the palatal root.