With Occluzer, testing should be carried out at clenching strength ≥ 60% MVC. With BiteEye, testing should be carried out from light clenching strength at 20% MVC to moderate clenching strengths at 40-60% MVC. Occluzer and BiteEye (10 μm) gave similar occlusal contact areas at 60-80% MVC. These results suggest that combined use of Occluzer and BiteEye gives an accurate picture of occlusion from weak to strong clenching strength.

The purpose of this study is to evaluate the effects of the number and the placement of implants on load distribution for multiple implants with three-dimensional geometric analysis, and to verify the well-known conceptual figure by Rangert. Three teeth missing in left mandibular region was geometrically modelled in clinically simulated situation. Two implants placement as 'control', 'cantilever', 'three-implants' and 'offset placements' were analyzed with geometric analysis. The cantilever received 180-182% load of control, that is, almost same to the result by Rangert (200%). Three implants received 59-65% load of control, that is, almost same to the result by Rangert (67%). Offset arrangement received 59-65% load of control, that is, larger than the result by Rangert (40%). It was concluded that the influence of the arrangement of implants on the load distribution presented in the conceptual figure by (Rangert BR, Sullivan RM & Jemt TM, J Oral Maxillofac Implants. 1997;12:360) was verified except for the effects of the offset arrangement.

BackgroundOcclusal contact on the implant superstructures is important for successful treatment. The purpose of this study was to investigate the occlusal contact of single implant superstructures at the mandibular first molar immediately after seating from weak to strong clenching.MethodsSubjects were nine patients who had just been fitted with an implant prosthesis in the mandibular first molar region, with no missing teeth other than in the implant region. First, while masseter muscle activity was monitored, maximum clenching strength (100 % maximum voluntary contraction (MVC)) was determined with an electromyogram. Next, occlusal load and occlusal contact area were measured three times at clenching intensities of 40, 60, 80, and 100 % MVC by the use of pressure-sensitive film for occlusal force diagnostic and Occluzer for occlusal force measurement. Finally, the occlusal contact area was measured once each at 20, 40, and 60 % MVC using a silicone testing material and BiteEye for occlusal contact measurement. A two-way analysis of variance (ANOVA) was used to determine occlusal loading and occlusal area as dependent variables, and clenching strength and presence or absence of implant as between-subject factors. A multiple comparison test was performed using the Bonferroni method.ResultsThe occlusal contact area and occlusal load of the implant prosthesis increased with clenching strength, and the increases in occlusal contact area and occlusal load of the implant prosthesis were less than those of the contralateral tooth at high clenching strength. However, significant difference was not observed when compared with both sides of the molar region regardless of clenching strength.ConclusionsThe occlusal contact area of the implant had a tendency to be adjusted smaller than the natural tooth by a dental technician and a dentist. On the other hand, despite the small tissue displaceability of the implant, occlusal load on the implant prosthesis was smaller than on the natural tooth at high clenching strength.

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