Influence of the thickness of silicone registration material as a means for occlusal contact examination – an explorative study with different tooth clenching intensities

Abstract

This study explored the influence of the thickness of silicone registration material on evaluation of the occlusal contact area and number of occlusal contact points, during increasing tooth clenching conditions in normal subjects. Twenty-four subjects with no more than one missing tooth per quadrant participated. Surface electro-myography was recorded from the masseter muscle. As a baseline measurement, intercuspal position was maintained with minimal force, and occlusal contact was recorded using blue silicone material. Occlusal contact was also recorded at 20% maximum voluntary contraction (MVC) and 40% MVC using visual feedback. The occlusal contact area and number of occlusal contact points were analysed using five levels of thickness of silicone registration material: Level 1 (0-149 μm); Level 2 (0-89 μm); Level 3 (0-49 μm); Level 4 (0-29 μm); and Level 5 (0-4 μm). The anterior part and the left and right posterior regions of the dental arch were analysed separately. At all detection levels, the occlusal contact area significantly increased from baseline to 20% MVC and to 40% MVC in the molar area (P < 0·05). In the anterior part, the occlusal contact area significantly increased from baseline to 20% MVC and to 40% MVC only when using Level 5. The number of occlusal contact points significantly increased from baseline to 20% MVC and to 40% MVC only when using Level 5 in the molar area (P < 0·05). It suggested that occlusal contacts may be different at low tooth clenching intensity with potential effects on the teeth or periodontal tissues.

Comparing the occlusal contact area of individual teeth during low-level clenching

“…Silicone recording materials thicker than 5 mm were unable to calculate the OCA using this occlusal analysis device, therefore silicone recording materials were trimmed to less than 5 mm thick to maintain exact transmittance. As previously described (14), the OCA thicknesses were defined as level 1 (<150 µm: 0-149 µm), level 2 (<90 µm: 0-89 µm), level 3 (<50 µm: 0-49 µm), level 4 (<30 µm: 0-29 µm), and level 5 (<5 µm: 0-4 µm) in the image to calculate the OCA. The OCA in each tooth was divided using a maxillary tooth image on the computer screen and calculated from three jaw motor tasks according to the five thickness levels.…”

“…Gurdsapsri et al compared OCAs at different levels of maximum voluntary tooth contraction (MVC) (10%, 30%, 70%, and 100%) controlled by electromyography (EMG) visual feedback, and observed a significant increase in the OCA with higher tooth clenching intensity (13). A previous study showed that occlusal contacts differed with low-intensity tooth clenching (14). However, the OCA has not yet been measured in individual teeth.…”

Influence of different narrative instructions to record the occlusal contact with silicone registration materials

“…The silicone recording materials were trimmed to the appropriate thickness within 5 mm to keep the exact transmittance before the actual analysis. An occlusal analytic device (BITE EYE BE‐I, GC) was used for the analysis of the occlusal contact area and points . In the present study, occlusal contact area and point was defined as the thickness of silicone material was <30 μ m in silicone occlusal records, and the occlusal contact area and point were calculated for each task.…”

“…In the present study, occlusal contact area and point was defined as the thickness of silicone material was <30 μ m in silicone occlusal records, and the occlusal contact area and point were calculated for each task. The anterior zone and the left and right posterior zone were analysed separately following previous study . To evaluate repeatability between first and second occlusal contact area and point measurement, ICC was calculated from these values.…”

“…We showed that registration of occlusal contact for intercuspation using silicone material is not stable at 10% MVC but were stable at 20% MVC and continued to be at 40% MVC. Therefore, it may be that adequate clenching force is required to register the appropriate occlusal contact . However, these are the results from controlled tooth clenching with EMG feedback, and it is unknown whether narrative instructions to patients can give stable and correct occlusal recording in the clinical setting.…”