The initial clamping force, or preload, is created when the elastic recovery of a dental implant screw creates a force that pushes the abutment and the dental implant together. This occurs within the neck of the screw, in between the head of the screw and the first mating thread. When the clamping force is greater the external forces the screw should not loosen, however, this requires an accurate clamping force calculation. Although a clamping force calculator doesn’t exist, the force can be calculated if the coefficient of friction is known. Other factors that affect the calculation include screw stiffness and geometry, the rate of tightening, and the integrity of the hardware. Accurate preload is extremely important in implant dentistry and prevents the screw from coming loose by improving the fatigue strength of the screw and its locking effect. In cases of moderate lateral loads, 75% to 90% of the material elastic limit may be necessary to prevent the loosening of the screw.
Glossary
Clarithromycin
Clarithromycin is a semisynthetic macrolide antibiotic used in the treatment of orofacial infections caused by gram-positive cocci and susceptible anaerobes. Its mechanism of action involves the prevention of bacterial growth by interfering with protein synthesis. It is an alternate drug used for antibiotic prophylaxis. Clarithromycin is an effective drug for patients who are allergic or have sensitivities to penicillin. Clarithromycin is often used in the treatment of dental abscesses. Such abscesses can be either periapical, inside the tooth itself, or periodontal, within the gums. Though there are some at-home measures that can be taken to temporarily relieve symptoms, orofacial infections and oral abscesses require antibiotics to eliminate the bacteria and properly heal. The dosage and length of time prescribed will depend upon the severity of the infection and any underlying conditions. Patients should complete their entire prescription as directed to avoid re-infection, partial healing, or further damage to teeth and gums.
Clavulanic acid
Clavulanic acid is a beta-lactamase inhibitor that is sometimes combined with penicillin group antibiotics to overcome certain types of antibiotic resistance. Patients suffering from a tooth or oral infection due to poor oral hygiene, tooth decay, abscess, gum disease, or injury are generally prescribed an antibiotic to destroy the bacteria at the source of the infection. Though the initial infection may be located in a tooth or surrounding tissues, if left untreated, it may spread to other parts of the face, head, or even to the brain. To prevent this and to ensure that even some antibiotic-resistant strains are eliminated, practitioners may prescribe a penicillin-derived drug along with clavulanic acid in a more aggressive treatment. Though other antibiotics, such as azithromycin, clindamycin, or metronidazole, may be used for those who are allergic to penicillins, an amoxicillin/clavulanic acid combination has proved to be equally as effective, especially when compared to the results and side-effects of clindamycin.
Clean technique
The clean technique refers to a surgical procedure that takes place in a clinical setting. All instruments, implants, grafts, and irrigation solutions used are sterile. Surgeons wear sterile gloves, but hospital operating room level sterility is not achieved. The surgeons and assistants wear non-sterile attire and the patient is not necessarily covered by sterile drapes. This technique minimizes the contact with pathogens or potential pathogens that may be encountered during procedures such as dental fillings and dental care. Though hospital-level sterile environments are not required, practitioners utilizing the clean technique still follow tight guidelines and regulations to avoid cross-contamination or pathogen exposure to either themselves or the patient. Any tools, equipment, attire, and solutions used for one patient are not re-used for another patient nor are they taken into another procedure room. In addition, many tools and tool accessories are disposable and come sterile and pre-packaged for the patient’s protection.
Clindamycin
Clindamycin is a lincosamide antibiotic used in the treatment of orofacial infections caused by anaerobic bacteria. It is also active against aerobic bacteria, such as streptococci and staphylococci. Clindamycin is an alternate drug used for patients who are allergic to or intolerant of penicillin and penicillin-derived drugs. Oral infections often involve infection caused by more than one type of bacteria. Since clindamycin is effective against both aerobic and anaerobic bacteria, it can treat a wide variety of bacterial pathogens and is therefore a good choice for infections of the teeth, gums, and mouth. Though most patients take clindamycin orally, in some cases, the drug may also be given intravenously. The dose a patient is prescribed will depend on the type of infection being treated as well as patient factors such as age and weight. Though clindamycin has a low risk of serious side effects, it can cause stomach upset, throat irritation, and loss of appetite.
Clipping function
Clipping function is a software application that can virtually slice through a 3D volumetric reconstruction derived from CT/CBCT data in various planes. In implant creation and placement, detailed images of the patient’s mouth and dentition must first be acquired. These images are then used to create models of the patient’s mouth and also of the planned implant or prosthesis. This allows the practitioners and technicians to determine if the planned implant placement is possible or if adjustments are required. The use of the clipping function is another tool that provides additional views of the patient’s dentition and oral structure prior to any procedure being performed. It allows practitioners and technicians to see the oral anatomy that otherwise could not be viewed in an office examination. The use of such technology has reduced the number of errors made and adjustments required in the creation of an oral implant or prosthesis.
Closed-Tray Impression
The closed-tray impression, or indirect impression, is an impression technique that uses an impression coping with positioning features around which a rigid elastic impression material is injected. After removal of the impression, the coping is unthreaded from the mouth, connected to a laboratory analog, and repositioned into the impression prior to pouring. A closed-tray impression is typically used when a patient’s implants are or will be mostly parallel to each other. It is not an efficient impression technique for non-parallel implants. The closed-tray technique may also be used when there is not enough room for screw-retained impression copings and/or when there is a reduced interarch distance. Another benefit of the closed-tray impression technique is that it is an efficient way to obtain an image of both the implant and the natural teeth in the same impression. To avoid any errors in the proper capture of the impression, it is important that the tray is properly seated without interference from the abutments or screws.
Cluster (Implant) Failure
Cluster (implant) failure refers to the occurrence of multiple dental implant failures in one patient. It can also refer to multiple implant failures in a minute group of patients that have been derived from a large pool of subjects. There are several possible causes behind cluster implant failures in a minute group. A practitioner may become less exacting in their placement techniques and may begin using shortcuts. The complexities in patient cases may also increase which can lead to a higher rate of implant failures within that patient group. Changes in the manufacturing of the hardware or implants themselves may also lead to an increase in failure rate. Finally, chance may also play a roll in cluster implant failure. There may be no changes to a practitioner’s technique, to the implants or hardware, or to the complexity of patient cases yet simply by chance, implant failures can take place in a cluster of patients that appear to make the failure rate much higher.