Glossary

Neurotmesis is a nerve injury involving a complete severance of the nerve trunk leading to Wallerian degeneration. Due to the severing of the nerve trunk, sensory and/or motor functions are impaired with the potential for recovery being very small. In implant dentistry, neurotmesis may be caused by an accidental incision of the nerve or any of the factors leading to axonotmesis. Neurotmesis may be caused in several different ways during a surgical procedure. First, the needle used in the injection of numbing medications prior to the surgery can nick, damage, or lacerate the nerve trunk. In addition, the medication itself may cause chemical damage if it is injected directly into the nerve. During the surgery itself, the nerve and/or nerve trunk may also be damaged due to excess movement or manipulation or through compression. A direct surgical mistake which leads to the severe laceration or severing of the nerve trunk can also be the cause of neurotmesis.

The nominal implant length or diameter is the length of diameter of a dental implant as written on the manufacturer’s label. When placing an implant, it is essential that a surgeon does not exceed the parameters on the label or damage could be done to the patient’s bone, soft tissues, nerves, or other oral structures. Each type of implant has its own nominal length or diameter and the practitioner should have detailed knowledge of what these parameters are prior to placing them. The nominal implant length or diameter also applies to the relationship between an abutment and an implant. The diameter of each should be checked to ensure they are the correct size. Differences in size between the implant and implant hardware could lead to implant failure or injury to the patient. Most manufacturers have made the nominal implant lengths and diameters available on their websites as well as on the packaging.

The terms nonabsorbable and nonresorbable have similar meanings as both refer to the property exhibited by non-autogenous substances that demonstrate no in vivo degradation over time. In dental applications, nonabsorbable and nonresorbable materials may be used in a variety of applications including sutures. Nonabsorbable sutures cannot be broken down by the body and remain in place until removed by the practitioner. Nonresorbable membranes are another type of dental aid that can be utilized following osteotomies and implant preparation procedures. The use of dental materials that do not break down in the body ensure that proper healing can take place over an extended period of time without interruption due to loss of the healing aids. Since the mouth comes in contact with or is home to many types of microbes and foreign substances, nonabsorbable and nonresorbable materials are an essential part of oral health following a procedure or surgery.

There are two different types of abutments that a dental implant surgeon can choose to use depending on the type of restoration needed and the patient’s biological, aesthetic, and functional needs. Which abutment is selected plays an important role in the overall success of a dental implant and should be done carefully. A non hexed or non hex abutment are generally used when dental prosthetic units need to be connected, such as in the case of a bridge. This is due to the fact that using hex abutments for this purpose is quite difficult, and placement can be challenging due to line of insertion. In contrast, hex abutments are typically utilized for any dental restoration that has the potential to rotate in the mouth, such as a single crown. Hex abutments help prevent rotation, and are not needed to stabilize dental prosthetics that are joined together.

Membranes are utilized in guided bone and tissue regeneration procedures. They act as mechanical and biological barriers against soft tissue and other cells not required for bone formation that can invade the surgical space. There are generally two types of membranes — non-resorbable and resorbable. A non-resorbable membrane cannot be absorbed by the body during healing, because it is created from a high-density and microporous dPTFE, also known as polytetrafluoroethylene. This material is considered biologically inert and does not react to chemicals, making it a good choice for the moist, bacteria-filled environment of the mouth. However, it does need to be surgically removed after a period of a few weeks after bone growth has occurred. In contrast, a membrane made from bioresorbable polyactide (PLA) can be used to help create blood clot formation that is conducive to healing and promotes healthy blood flow. Both types of membrane have had good clinical results.