Dental implants

Dental implants

1. What are dental implants?

  • A dental implant is a “root” device, usually made of titanium, used in dentistry to support restorations that resemble a tooth or group of teeth to replace missing teeth. Virtually all dental implants placed today are root-form endosseous implants, they appear similar to an actual tooth root (and thus posses a “root- form”) and are placed within the bone. The bone of the jaw accepts and Osseo integrates with the titanium post. Osseo integration refers to the fusion of the implant surface with the surrounding bone. Dental implants will fuse with bone, however they lack the periodontal ligament, so they will feel slightly different than natural teeth during chewing. Prior to the advent of root-form endosseous implants, most implants were either blade endosseous implants, in that the shape of the metal piece placed within the bone resembled a flat blade, or subperiosteal implants, in which a framework was constructed to lie upon and was attached with screws to the exposed bone of the jaws.
  • Dental implants can be used to support a number of dental prostheses, including crowns, implant supported bridges or dentures. They can also be used as anchorage for orthodontic tooth movement. The use of dental implants permits unidirectional tooth movement without reciprocal action. The amount of time required to place an implant will vary depending on the experience of the practitioner, the quality and quantity of the bone and the difficulty of the individual situation.

2. What is the healing time?

  • The amount of time required for a dental implant to become osseointegrated is a highly debated topic. Consequently the amount of time that practitioners allow the implant to heal before placing a restoration on it varies widely. In general, practitioners allow 2-6 months for healing but preliminary studies show that early loading of implant may not increase early or long term complications. Minimally invasive methods of early dental implant placement reduce the cost of installed implants and shortens the implant prosthetic rehabilitation on time with 4-6 months. If the implant is loaded too soon, it is possible that the implant may move which results in failure. For conventional dental implants, the subsequent time to heal, possibly graft, and eventually place a new dental implant may take up to eighteen months. For this reason many are reluctant to push the envelope for healing.

3. One-stage, Two- stage surgery?

  • One-stage dental surgery is when on an implant is placed either a “healing abutment” which comes through the mucosa, on a “cover screw” which is flush with the surface of the dental implant to be placed. When a cover screw is placed, the mucosa covers the implant while it integrates then a second surgery is completed to place the healing abutment.
  • Two- stage dental surgery is sometimes chosen when a concurrent bone graft is placed or surgery on the mucosa may be required for esthetic reasons. The latter is usually important when an implant is placed in the “esthetic zone”. This allows more control over the healing and as a result the predictability of the final result. Some implants are one piece so that no healing abutments is required. In carefully selected cases, patients can be implanted and restored in a single surgery, in a procedure labeled “immediate loading”. In such cases a provisional prosthetic tooth or crown is shaped to avoid the force of the bite transferring to the implant while it integrates with the bone.

4. Which is the surgical timing?

There are different approaches to place dental implants after tooth extraction:

a) Immediate post-extraction dental implant placement

b) Delayed immediate post-extraction implant placement (2 weeks to 3 months after extraction)

c) Late implantation (3 months or more after tooth extraction)

Teeth in a Day:

  • “Teeth in a day”, “All-on-four”, “Fast and fixed” are similar surgical concepts whereby dental implants are placed on the same day and a fixed prosthesis is attached to them. This allows the patient to leave with a fixed solution as opposed having to make do with a removal temporary prosthesis whilst the implant osseointegrate with the bone. This concept is appropriate for completely edentulous jaws where either the teeth are to be extracted or have been removed.

5. Which are the complementary procedures?

Sinus lifting is a common surgical intervention. A dentist or specialist with proper training such as an oral surgeon, periodontist, general dentist or prosthodontist, thickens the inadequate part of atrophic maxilla towards the sinus with the help of bone transplantation or bone expletive substance. This results in more volume for a better quality bone site for the implantation. Prudent clinicians who wish to avoid placement of implants into the sinus cavity, pre-plan sinus lift surgery using the CBCT X-ray.

Bone grafting will be necessary in case where there is lack of adequate maxillary or mandibular bone in terms of front to back (lip to tongue) depth or thickness ; top to bottom height ; and left to right width. Sufficient bone is needed in three dimensions to securely integrate with the root-like implant. Improved bone height – which is very difficult to achieve – is particularly important to assure ample anchorage of the implant’s root – like shape because it has to support the mechanical stress of chewing, just like a natural tooth.

Typically, implantologists try to place implants at least as deeply into bone as the crown or tooth will be above the bone. This is called a 1:1 crown to root ratio. This ratio establishes the target for bone grafting in most cases. If 1:1 or more cannot be achieved, the patient is usually advised that only a short implant can be placed and to not expect a long period of usability. A wide range of grafting materials and substances may be used during the process of bone grafting / bone replacement they include the patient’s own bone (autograft), which may be harvested from the hip (iliac crest) or from spare jawbone; processed bone from cadavers (allograft) which is demineralized, bovine bone or coral (xenograft); or artificially produced bone – like substances (calcium sulfate with names like Regeneform and hydroxyapatite or HA, which is the primary form of calcium found in bone) or calcium phosphosilicate which is available in a moldable putty form. The HA is effective as a substrate for osteoblasts to grow on. Some implants are coated with HA for this reason, although the bone forming properties of many of these substances, is a debated topic in bone research groups. Alternatively the bone intended to support the implant can be split and widened with the implant placed between the two halves like a sandwich. this is referred to as a “ridge split ” procedure.

Bone graft surgery has its own standard of care. In a typical procedure, the clinician creates a large flap of the gum to fully expose the jawbone at the graft site, performs one or several types of block and only in and on existing bone, then installs a membrane designed to repel unwanted infection – causing microbiota found in the oral cavity. Then the mucosa is carefully sutured over the site. Together with a course of systemic antibiotics and topical antibacterial mouth rinses, the graft site is allowed to heal (several months).

The clinician typically takes a new radiograph to confirm success in width and height, and assumes that positive signs in these two dimensions safely predict success in the third dimension, depth. When more precision is needed, usually when mandibular implants are being planned, a 3D or cone beam radiograph may be called for at this point to enable accurate measurement of bone and location of nerves and vital structures for proper treatment planning. The same radiographic data set can be employed for the preparation of computer-designed placement guides. Correctly performed, a bone graft produces live vascular bone which is very much like natural jawbone and is therefore suitable as a foundation for implants.

Consideration: for the dental implant procedure to work, there must be enough bone in the jaw and the bone has to be strong enough to hold and support the implant. If there is not enough bone, more may need to be added with a bone graft procedure discussed earlier. Sometimes, this procedure is called bone augmentation, or guided bone regeneration. Mini dental implants are particularly useful in the edentulous arch with minimal remaining bone facio-lingually. In addition, natural teeth and supporting tissues near where the implant will be placed must be in good health. In all cases careful consideration must be given to the final functional aspects of the restoration, such as assessing the forces which will be placed on the implant. Implant loading from chewing and parafunction (abnormal grinding or clenching habits) can exceed the biomechanical tolerance of the implant bone interface and / or the titanium material itself, causing failure. This can be failure of the implant itself (fracture) or bone loss, a “melting” or resorption of the surrounding bone.

6. Which are the contraindications?

There are few absolute contraindications to implant dentistry. However, there are some systemic, behavioral and anatomic considerations that should be assessed. Particularly for mandibular (lower jaw) implant, in the vicinity of the mental foremen (MF), there must be sufficient alveolar bone above the mandibular canal also called the inferior alveolar canal or IAC (which acts as the conduit for the neurovascular bundle carrying the inferior alveolar nerve or IAN).

Uncontrolled Type II diabetes is a significant relative contraindication as healing following any type of surgical procedures is delayed due to poor peripheral blood circulation. Anatomic consideration includes the volume and height of bone available. Often an ancillary procedure known as a block graft or sinus augmentation are needed to provide enough bone for successful implant placement.

There is new information about intravenous and oral bisphosphonates (taken for certain forms of breast cancer and osteoporosis, respectively) which may put patients at a higher risk of developing a delayed healing syndrome called osteonecrosis. Implants are contraindicated for some patients who take intravenous bisphosphonates. The many millions of patients who take an oral bisphosphonate (such as Actonel, Fosamax and Boniva) may sometimes be advised to stop the administration prior to implant surgery, then resume several months later. However, current evidence suggests that this protocol may not be necessary. An oral bisphosphonate study reported in the Journal of Oral and Maxillofacial Surgery issued in February 2008 – reviewing 115 cases that included 468 implants – concluded “There is no evidence of bisphosphonate-associated osteonecrosis of the jaw in any of the patients evaluated in the clinic and those contacted by phone or e-mail reported no symptoms”.

Bruxism (tooth clenching or grinding) is another consideration which may reduce the prognosis for treatment. The forces generated during bruxism are particularly detrimental to implants while bone is healing ; micro movements in the implant positioning are associated with increased rates of implant failure. Bruxism continues to pose a threat to implants throughout the life of the recipient. Natural teeth contain a periodontal ligament allowing each tooth to move and absorb shock in response to vertical and horizontal forces. Once replaced by dental implants, the ligament is lost and teeth are immovably anchored directly into the jaw bone. This problem can be minimized by wearing a custom made mouth guard (such an NTI appliance) at night.

Postoperatively, after dental implants have been placed, there are physical contraindications, that prompt rapid action by the implantology team. Excessive or severe pain lasting more than three days is a warning sign, as is excessive bleeding. Constant numbness of the gum, lip and chin – usually noticed after surgical anesthesia wears off – is another warning sign. In the latter case, which may be accompanied by severe constant pain, the standard of care calls for diagnosis to determine if the surgical procedure IAN, a 3D cone beam X-ray provides the necessary data.

7. How painful is the dental implant procedure?

Dental implant  procedure, as any other surgical procedure, has some associated pain. However, many dental implant patients comment that they were surprised at how minimal the pain and discomfort of their procedure were, especially when performed under IV sedation.

Once the dental  implants are placed, your new teeth are fixed to the implants, and do not rest on your gums, thus avoiding aggravation to the surgical site. This can mean less pain than traditional dentures or other treatment approaches, and shorter duration of discomfort.

8. Does insurance cover the cost of dental implants?

Dental implant  treatment may qualify for some insurance coverage, but is generally limited to the coverage provided for a bridge or partial denture.

9. Am I too old to have dental implants?

Age appears not to be a factor for dental implant success. Bone healing around dental implants occurs in patients from 6th to the 10th decade of life with almost equal success as in younger patients. The only thing to stand in the way of dental implant treatment in the elderly is general medical health. There are a number of medical conditions that can preclude treatment; therefore, in addition to a general health history, a physical, blood studies and cardiograms may be required, as well as a release from your medical doctor.

10. How will I know if dental implants can be done in my case?

The implant exam and consultation will evaluate your mouth with a clinical exam and an X-ray in order to determine your potential for implants. The x-ray exam will be able to show how much bone is present in the locations where you will need implants placed. The X-ray will not be able to accurately show bone density.  

Dental implants in Romania, clinical cases in dental clinic Romania, performed by top dentists in Romania:

This blog post is an educational resource only and does not replace a medical consultation with a doctor .

Please feel free to get in touch if you have any questions or comments. Your feedback welcome!

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