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Medium- or long-term failure of endosseous dental implants after osseointegration, when it has occurred, has been associated in the great majority of cases with occlusal overload. Overload depends ultimately on the number and location of occlusal contacts, which to a great extent are under the clinician's control. Much of our current understanding of occlusal contacts in this context is based on concepts derived from non-implant-borne prosthetics and has not been rigorously tested. The present article reviews occlussal contact designs and offers occlusion strategy guidelines for the main types of implant-borne prostheses.

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The aim of this report is two-fold. First it analyses the precision of a modification of the parallel technique that can be used in those cases with anatomical limitations. Second, it checks the influence of the reference points' definition of objects to be measured by using both the original and the modified radiographic techniques. 2 intraoral radiographs were taken of 28 implants with 2 different methods: a standard paralleling technique and a modified technique that used a smaller film and a silicone spacer to ensure parallelism. Measurements of peri-implant bone levels and implant width were made in triplicate on digitized film radiographs. The results of the peri-implant bone levels were that with the parallel method the mean was 0.44 mm and the precision was 0.43 mm, and with the modified method the mean was 0.73 mm and the precision was 0.66 mm. In addition to the correct localization of the point of reference in this study, the precision with the parallel method was 0.08 mm and with the modified method was 0.13 mm. Although it was greater with the gold standard technique than with the modified technique, precision was very high for both methods and accurate enough for clinical use.

We studied the dental contact section of the chewing cycle, the most important section in terms of function (as it governs the effectiveness of food trituration). Specifically, we determined closing phase dental contact distance and lateral path inclination in a sample of healthy subjects, and investigated possible relationships between these variables and Ahlgren chewing cycle type. The chewing cycle was characterized in 63 healthy subjects by frontal plane kinesiography. In all cases kinesiographs were obtained for both right‐ and left‐side chewing, with chewing gum as bolus. In all cases we determined closing phase dental contact distance, lateral path inclination and Ahlgren chewing cycle type. Most subjects (84%) showed ‘normal’ chewing cycles (Ahlgren types I–IV); inverted, contralateral and irregular cycles (types V–VII) were infrequent. Mean dental contact distance was 0·9 mm for right‐side chewing and 1·2 mm for left‐side chewing. Mean lateral path inclination was 35° for right‐side chewing and 37° for left‐side chewing. Normal chewing cycles are generally bilateral, whereas abnormal chewing cycles are never bilateral. Border movement distance does not differ in any consistent way between ‘chopping’ and ‘grinding’ chewing cycle types. Closing phase dental contact distance showed a significant positive correlation with lateral path inclination.