Natural teeth versus implants
The physical differences between natural teeth and implants are often compared to the roots of teeth. Replacing the root of a tooth helps to maintain the bone, but there are fundamental differences.
It starts with the surface of a natural tooth (i.e., cementum) and the implant surface of titanium alloy or zirconia, rough, porous, or smooth, sometimes with coated surfaces to create a more biocompatible surface for the bone to osseointegrate with.
The key physical difference between a natural root and an implant is that the natural root is sensitive to heat and a pulpitis is possible, whereas an implant has no sense of temperature.
Also, implants are not susceptible to decay and natural teeth are, which is one reason implants are very good restorative choice for patients with controlled diabetes, xerostomia, or autoimmune disease.
Xerostomia patients who suffer from decreased saliva go from an increase in decay to broken teeth and eventually dentures without much success. If an implant is placed when the first tooth is lost, this cycle can be broken and the quality of life for these patients greatly improved.
Autoimmune diseases (e.g., AIDS, asthma, arthritis, or lupus) where the patient’s immune system is not functioning properly can be helped by implant therapy which does not rely on the host response to stay healthy.
The mobility of a natural tooth can cause a loss of attachment, periodontal disease, or trauma that can be reversed. The natural tooth can also test positive or negative for mobility due to periodontal disease or occlusion.
Implant mobility is caused by occlusion, trauma, or infection, but with a much more negative result, often the loss of osseointegration which means the loss of the implant.
Since an implant is held in by the bone with no periodontal ligament, such as a cement post in the ground, if it becomes mobile there is a good chance the implant will fail. The good news is that in most cases it can be replaced with a new implant.
The attachment of the tissue that surrounds the natural tooth and implants is where the bigger differences lie. The attachment of the gingival tissues to the neck of the implant is distinct from the attachment to natural teeth.
Both the natural tooth and the implant have junctional epithelium (hemidesmosomes and basal lamina) and sulcular epithelium but implants have no evidence of Sharpey’s fibers between an implant or implant abutment and bone.
The junctional epithelium of a natural tooth attaches to the tooth coronal to the bone up to 2 mm and has a sulcular epithelium of 2–7 mm with a definite connective tissue attachment.
The implant has only an adhesion attachment of connective tissue with a junctional epithelium up to 1.5 mm. It runs parallel and circular to the fixture with a sulcular epithelium of 0.5–1.0 mm, but these do not insert into the implant surface, making this attachment much more fragile and susceptible to damage by trauma and/or infection.
This tissue–implant interface is known as the perimucosal seal.
The perimucosal seal is the tissue barrier that prevents microorganisms and other inflammatory agents from the oral cavity from entering the tissues that surround the implant.
It contains the sulcular epithelium, and its presence is important for the longevity and success of the implants.
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