Abstract
The newly designed T-Scan 8 Computerized Occlusal Analysis system represents the state-of-the-art in occlusal diagnosis. The reliability of the system's high definition recording sensors, the many occlusal analysis timing and force software features, and the modern-day computer hardware electronics that record occlusal function in 0.003 second real-time increments affords a clinician unparalleled occlusal contact timing and force information with which to predictably diagnose and treat many occlusal abnormalities. T-Scan 8 represents the culmination of 30 years of T-Scan technology innovation and development with revised desktop graphics and less toolbar buttons for simpler graphical display designed to shorten the T-Scan learning curve. The chapter also discusses five useful diagnostic occlusal recordings employed when treating commonly observed occlusal problems. Lastly, the chapter outlines the three Learning Levels of T-Scan mastery that must be accomplished for a clinician to become an effective and competent T-Scan user.
TopIntroduction
Present day computerized occlusal analysis represents the State of the Art in occlusal diagnosis. T-Scan 8 (Tekscan, Inc., S. Boston, MA, USA) represents the culmination of thirty years of T-Scan technology innovation into the science of Dental Occlusion. T-Scan 8 has revised desktop graphics for simpler display, with less toolbar buttons and icons to minimize clinician complexity, which had made previous T-Scan versions somewhat difficult to readily learn and effectively implement clinically. The combination of the reliability of the High Definition (HD) T-Scan recording sensors, the occlusal timing and relative force analysis software features, and the modern-day computer hardware electronics, affords the clinician unparalleled occlusal force and timing information, with which to diagnose and treat a wide range of commonly observed occlusal problems. The T-Scan technology’s studied abilities to measure time durations (Kerstein &Wright 1991;Hirano, Okuma, & Hayakawa, 2002), illustrate ordered tooth contact time-sequences (Kerstein, Chapman, & Klein, 1997: Koos, Holler, Schille, & Godt, 2012), reproduce relative occlusal force (Kerstein, Lowe, Harty, & Radke, 2006; Koos, Godt, Schille, & Göz, 2010), and locate excessively forceful occlusal contacts (Maness, 1988; Maness, 1991), is a vastly superior diagnostic method compared to the commonly utilized, non-digital occlusal indicators which dentists routinely employ to determine occlusal contact force levels (articulating paper markings, wax imprints, silicone imprints, and articulated stone dental casts (Kerstein, 2010). None of these dental materials have demonstrated any scientifically proven capability to record tooth contact time-sequences, or describe relative differences in contact occlusal force levels. Moreover, all of these non-digital occlusal indicators require the clinician to “Subjectively Interpret” their meaning and their supposed occlusal function representations (Kerstein &Radke, 2013).
T-Scan 8 has a definitively simpler user presentation, designed to shorten the learning curve for the clinician while standardizing the display and eliminating any significant clinician preferential software set up options present in prior T-Scan versions. Desktop changes from T-Scan 7 include an enlarged Force vs. Time graph for easier visualization of all the color-coded force and timing lines, and a rotating 3-Dimensional ForceView window that improves the visualization of the moving individual force columns observed during movie playback. The rotating 3-D ForceView allows the clinician to orient the window in any view that during playback, best eliminates the overlap of the rising and falling force columns (Figure 1).
Figure 1. The T-Scan 8 desktop with a rotating 3-dimensional ForceView window, and an enlarged force vs. time graph
Clinically, the T-Scan 8 system is used to record a number of distinctly different functional mandibular movements that illustrate to the clinician, differing aspects of a given patient’s occlusal contact force and time-sequencing patterns. Occlusal data is gathered by the patient occluding into and compressing the HD recording sensor, and then making repeated closures, or excursive movements across its’ surface.
Recording quality occlusal force and timing data from which to diagnose a patient’s occlusal condition is successfully accomplished by utilizing one or more of the following occlusal function recording types:
Key Terms in this Chapter
Force vs. Time Graph: An important T-Scan software analysis tool that displays the changing forces as they were recorded in sequence across time, for the entire duration of functional mandibular movement that was recorded. The Force vs. Time Graph can also describes the changing forces of any individually selected teeth by using the Tooth Timing software feature. In addition, the Force vs. time Graph can describe the changing forces of any Force Outlier teeth, when that software feature is selected by the clinician. The Force vs. Time Graph uses differing line color-coding that is a visual reference to differing areas of the 2D ForceView arch model. The graph can also describe four quadrants of force instead of two quadrants in arch-halves, when the Quadrant Division Tool is activated by the clinician.
Center of Force and Trajectory: The history of changing total occlusal force summation is located positionally with the dental arches by the Center Force Trajectory. As forces evolve on individual teeth in sequence, the force summation will move towards higher force concentrations and away from lesser concentrations, throughout the entire functional mandibular movement that was recorded. These force summation changes are graphically displayed during playback within the 2D ForceView by a red and white diamond-shaped icon, followed by its’ red colored-line trailer.
Force Percentage per Tooth: Force Percentage per Tooth software feature describes unequal or equal, individual tooth force distributions between each arch-half. Corrective occlusal adjustments can be accomplished to better equalize force percentage per tooth discrepancies, which are based upon the right percentage per tooth comparison to its’ left percentage per tooth counterpart.
Force Outliers: Force Outliers are individual tooth contacts that demonstrate much higher relative force than others, at any given moment during a mandibular closure. As a movie plays forward from the first contact, occlusal contacts that exceed a higher relative force threshold compared to other contacting teeth, are denoted with an individually colored outline in both the 2D and 3D ForceViews. These contacts are designated as an outlier , when that outlier passes a higher force threshold compared to the rest of the occluding teeth. The Force vs. Time Graph removes the Total Force Line and instead, represents each Force Outlier that occurred throughout the recording.
Disclusion Time: The elapsed time in seconds, measured from the beginning of an excursive movement that is commenced with all teeth in complete intercuspation, and is made in one direction through until only canines or incisors are in contact. The Disclusion Time can be measured in three different excursive movements; the Right Excursion, the Left Excursion, and the Protrusive Excursion. In the Force vs Time Graph, the Disclusion Time is quantified within the C-D period. < 0.4 seconds from excursive commencement until posterior disclusion is considered as immediate, and is desirable physiologically.
Occlusion Time: The elapsed time in seconds, measured from the 1 st tooth contact until the last tooth contact, as a patient closes all their teeth together from completely open with no tooth contact, until the beginning of static intercuspation, which occurs before the patient achieves maximum intercuspation. The Occlusion Time describes the degree of bilateral simultaneity present in a patient's occlusion and has been deemed ideal if it is < 0.2 seconds in duration. In the Force vs Time Graph, the Occlusion Time is quantified within the A-B period.
T-Scan 8: The most modern version of the T-Scan system released in 2012, that was purposefully designed to minimize the T-Scan III’s user interface complexity. T-Scan 8 has revised desktop graphics for simpler data display with many less software toolbar buttons and icons. The simplified presentation is designed to shorten the T-Scan’s learning curve and standardize the display, by removing most of the preferential software set up that was available to clinicians in T-Scan III.
Digital Output Voltage (DO): The electronic output from resistance changes that occur within each loaded sensel as teeth occlude into the sensor matrix. The T-Scan system’s hardware electronics measures these resistance changes, as a change in Digital Output Voltage (DO). Higher occlusal forces result in larger decreases in loaded sensel resistance, which gives off a higher measured output voltage. Alternatively, the lower the applied force, the lower is the measured output voltage.
2D and 3D ForceViews: The 2D ForceView displays the occlusal contacts in 2 Dimensions; both mediolaterally and anteroposteriorly. The 3D ForceView displays the occlusal contact forces in 3 Dimensions with moving and changing column heights that reflect varying relative occlusal force levels, that change over time. The recorded occlusal force data is displayed with the lowest forces being represented in blue and the highest forces being represented in red, or in saturated pink.
Functional Mandibular Movements: These are the mandibular movements that occur both during chewing function, and during parafunctional activity. Patient self-closure, Centric Relation closure, lateral excursive movements, and clenching and grinding movements, are the main functional mandibular actions that the T-Scan can record.
Recording Sensel: Tekscan’s proprietary electronic force measuring element contained within the sensor matrix. When the patient occludes upon an HD sensor and opposing tooth contacts is compress the top and bottom sensor surfaces, a change in the applied force at the various tooth contacts results in a change in the resistance of the resistive ink in each of the contacted sensels. Higher applied contact force produces larger resistance changes and lower occlusal contact force produces lesser resistance changes. A large HD sensor contains 1370 sensels. A small HD sensor contains 1122 sensels.