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Immediate Loading It has also been demonstrated that immediate loading is compatible with subsequent successful osseointegration, provided the bone quality is good and the functional forces can be adequately controlled. In studies on single tooth restorations, the crowns are usually kept out of contact in intercuspal and lateral excursions, thereby almost eliminating functional loading until a definitive crown is provided. In contrast, fixed bridgework allows connection of multiple implants providing good splinting and stabilization and therefore has been tested in immediate loading protocols with good success. However, the clinician should have a good
reason to adopt the early/ immediate loading protocols particularly as they are likely to be less predictable

useful in experimental trials and rapid treatment protocols. The simplest categorization of bone quality is that described by Lekholm as types 1 to 4. Type 1 bone is predominantly cortical and may offer good primary stability at implant placement but is more easily damaged by overheating during the drilling process, especially with sites over 10 mm in depth. Types 2 and 3 are the most favorable quality of jaw bone for implant treatment. These types have a well-formed cortex and densely trabeculated medullary spaces with a good blood supply (type 2 has more cortex/dense trabeculation than type 3). Type 4 bone has a thin or absent cortical layer and sparse trabeculation. It offers poor primary implant stability and fewer cells with a good osteogenic potential to
promote osseointegration, and has therefore been associated with higher rates of implant failure.

Many of the currently available implant systems have some of the features described above. They tend to have an internal connection between abutment and implant that is either parallel sided with a small area of flat surface at the top or a conical design (Fig. 1.15). Most feature an internal hexagonal/octagonal anti-rotational system with an abutment screw but some rely on the frictional fit of a Morse taper cone. With internal connection designs there has also been a trend to make the abutment diameter smaller than the implant head resulting in a “negative” margin. This so-called platform switching allows a greater volume of soft tissue in this region and may contribute to maintenance of implant bone levels by increasing the available surface distance in establishing the soft tissue biological width. The improved seal of internal connections may also reduce or
eliminate bacterial ingress and subsequent inflammation that could affect bone levels.

In a patient who presents with an acute facial swelling and signs of general distress, there is a possibility that the dental infection may have spread systemically. Although these types of cases are rare, when they present it is imperative that the clinician can identify a provisional diagnosis and take appropriate action swiftly. Recording body temperature and noting difficulty in swallowing in a patient who is clearly suffering with malaise or fatigued from acute symptoms will give an indication of systemic involvement or local spreading infection. Difficulty in breathing may indicate a restricted airway due to sublingual spread of infection (of possible endodontic origin). This requires referral to hospital for admission as the health of the patient can rapidly deteriorate.

Failures were related to fractures/chipping (4%), followed by endodontic complications (3%), secondary caries (1%) and debonding (1%). More failures were reported in molars and root-treated teeth