Articulating paper mark size has been widely accepted in the dental community to be descriptive of occlusal load. The objective of this study is to determine if any direct relationship exists between articulating paper mark area and applied occlusal load. A uniaxial testing machine repeatedly applied a compressive load, beginning at 25N and incrementally continuing up to 450N, to a pair of epoxy dental casts with articulating paper interposed. The resultant paper markings (n = 600) were photographed, and analyzed the mark area using a photographic image analysis and sketching program. A two-tailed Student's t-test for unequal variances compared the measured size of the mark area between twelve different teeth (p < 0.05). Graphical interpretation of the data indicated that the mark area increased non-linearly with increasing load. When the data was grouped to compare consistency of the mark area between teeth, a high variability of mark area was observed between different teeth at the same applied load. The Student's t-test found significant differences in the size of the mark area approximately 80% of the time. No direct relationship between paper mark area and applied load could be found, although the trend showed increasing mark area with elevating load. When selecting teeth to adjust, an operator should not assume the size of paper markings, accurately describing the markings' occlusal contact force content.

No abstract

PURPOSEArticulation paper mark size is widely accepted as an indicator of forceful tooth contacts. However, mark size is indicative of contact location and surface area only, and does not quantify occlusal force. The purpose of this study is to determine if a relationship exists between the size of paper marks and the percentage of force applied to the same tooth.MATERIALS AND METHODSThirty dentate female subjects intercuspated into articulation paper strips to mark occlusal contacts on their maxillary posterior teeth, followed by taking photographs. Then each subject made a multi-bite digital occlusal force percentage recording. The surface area of the largest and darkest articulation paper mark (n = 240 marks) in each quadrant (n = 60 quadrants) was calculated in photographic pixels, and compared with the force percentage present on the same tooth.RESULTSRegression analysis shows a bi-variant fit of force % on tooth (P<.05). The correlation coefficient between the mark area and the percentage of force indicated a low positive correlation. The coefficient of determination showed a low causative relationship between mark area and force (r2 = 0.067). The largest paper mark in each quadrant was matched with the most forceful tooth in that same quadrant only 38.3% of time. Only 6 2/3% of mark surface area could be explained by applied occlusal force, while most of the mark area results from other factors unrelated to the applied occlusal force.CONCLUSIONThe findings of this study indicate that size of articulation paper mark is an unreliable indicator of applied occlusal force, to guide treatment occlusal adjustments.

The purpose of this study was to determine if a statistically significant reduction in muscle activity (p<0.05) occurs when prolonged disclusion time (>0.4 sec/excursion) is shortened to <0.4 sec/excursion with the Immediate Complete Anterior Guidance Development (ICAGD) enameloplasty. Forty-five symptomatic, fully informed subjects (29 female, 16 male) had their right and left disclusion times recorded with T-Scan III, while simultaneously, the bilateral masseter and anterior temporalis muscle activity was recorded electromyographically with BioEMG III (n=180 muscles). This recording was done twice, once pretreatment and again posttreatment (same day) after undergoing the ICAGD enameloplasty on the same day without changing electrodes. The Student's paired t-test was utilized to detect any significant change in the muscle activity levels between the pre- and posttreatment lateral excursive muscle contractions. Highly significant reductions were found in all four muscles' activities after shortening the pretreatment prolonged disclusion time to less than 0.4 seconds (p<0.0014); after Bonferroni correction (p<0.006). When properly performed, such that the posttreatment disclusion time is <0.4 sec/excursion, the ICAGD enameloplasty predictably reduces excursive muscle activity levels in the bilateral anterior temporalis and masseter muscles. Excursive muscle hyperactivity can be a source of lactic acid accumulation, muscular ischemia, and chronic myalgic temporomandibular joint dysfunction (TMD) symptoms. The ICAGD enameloplasty significantly reduces excursive muscle contractions after completion of the first ICAGD treatment session.

The purpose of this study was to measure the performance of a new design of occlusal sensor, the high definition (HD) sensor, and directly compare this sensor to the previous design. This new HD sensor design has increased active recording area by 33%, and decreased inactive recording area by 50% as compared to the previous design (G3). This was accomplished by determining the force reproduction variability for repeated occlusal closures on the same sensor for a sampling of sensors from both designs. Thirty (30) G3 and 30 HD sensors were consistently positioned and loaded 24 times between articulated epoxy casts by a Pneumatic Occlusal Force Simulator. Their force reproduction consistency was measured as an electronic voltage drop across six occlusal contacts that were consistently located on all sensors. The force variability of the two sensor designs was determined by comparing the consistency of the voltage drops across the six occlusal contacts. An analysis of variance was employed to determine the variability of force reproduction over multiple closures across six occlusal contact regions. For five of the six contacts, the G3 sensor mean variances, were significantly larger (p < 0.05) than those of the HD sensor. The within sensor variability of the HD sensor was significantly less than that of the G3 sensor. Within the limitations of this study, the HD sensor exhibited less variable force reproduction than the G3 sensor for at least 20 in-laboratory loading cycles.