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wing radiographs are useful for posterior teeth; the orthopantomograph (OPG) provides an overall picture, but detail of the alveolar margin is frequently ill declined. Repeat radiographs may be necessary; at intervals (not less than 3 years) determined by patient susceptibility, to show progression.
     8. Occlusion. The examination of occlusion should include:
(a)The Angle’ s classification
     (b) Overbite and overjet
     (c) Tooth relation in protrusive and lateral positions and movements
     (d) Any deviation from the normal path of opening and closure
     (e) Any temporomandibular joint (TMJ) discomfort or clicking
     (t) Any history of habits, e.g. clenching or grinding the Teeth. The occlusion needs to be examined closely where:
     (a)Teeth are mobile or sensitive
     (b) There is discomfort, clicking, deviation of the mandible on opening and closing, or limitation of movement
     (c) Radiographs show widening of the periodontal spaces or vertical bone defects, i.e. Possible signs of excessive occlusal stress.

     Special tests
     If the severity of the inflammation or the degree of periodontal destruction appears to be out of proportion to the observed aetiological factors, or if general appraisal of the patient suggests that some systemic factor may be operating, then blood and urine examination or other special tests may be required. In such cases it is imperative to communicate with the patient’ s physician prior to the start of treatment.
     Making a prognosis.
     A prognosis is a prediction of the way in which the tissues are likely to respond to treatment.     Before a definitive treatment plan can be formulated, a prognosis must be made. This should allow one to establish not merely what treatment can be carried out but, more important, what treatment is justified in the attempt to achieve long-term periodontal stability. Frequently the patient will ask that such a prediction be made, and the more complicated the treatment the more important making a prognosis becomes. Looking into the future can be a hazardous exercise but a prediction of the way in which the periodontal tissues will behave can be made on the basis of an understanding of the way in which the tissues of that individual have behaved in the past in the face of disease-producing factors.
     A number of parameters need to be considered:
     1. The extent of periodontal destruction. This is represented by the amount of alveolar bone loss as seen on the radiograph; obviously the greater the amount of bone loss, the poorer the prognosis.
     2. The age of the patient. This, together with the extent of periodontal destruction, provides an idea of the rate at which destruction has taken place. The older the individual, the better the prognosis for any given degree of periodontal destruction.
     3. The form of the bone loss. The presence of vertical bone defects must mean a less favourable prognosis than where bone loss is horizontal for several reasons;
     (a) Because the level of