Abstract
The newly designed T-Scan 10 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 10 represents the culmination of 34 years of T-Scan technology innovation development. T-Scan 10 has revised desktop graphics with additional toolbar buttons that enhance T-Scan functionality and improve chairside T-Scan clinical implementation. The system's most recent important advancement, discussed in this chapter, is the melding of T-Scan digital occlusal force and timing data with digitally-scanned dental arches to overlay T-Scan data on a patient's virtual arch. This is a major system upgrade that inserts the T-Scan technology directly into the digital dentistry revolution presently arising in dental medicine. The chapter details the five useful diagnostic occlusal recordings employed when treating commonly observed occlusal problems, and lastly 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 10 (Tekscan, Inc., S. Boston, MA, USA) represents the culmination of thirty-four years of T-Scan technology innovation into the science of Dental Occlusion. T-Scan 10 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 10 has a similar user presentation as T-Scan 8, 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. Important desktop changes maintained from T-Scan 8 include the 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, to best eliminate the overlap of the rising and falling force columns (Figure 1a). With T-Scan 10, the main desktop Toolbar displays additional icons that activate important new software features that were recently added into the newest version of the program. Doctors can import and export patient data, generate reports, attach notes and photos, and create MP4 files of the scan, while also being able to import intraoral digitally- impressed .stl files of a patient’s arch, which can then be overlaid with T-Scan force data (Figure 1b). Additional new tools include the Force Eraser that allows the clinician to remove from a scan sensor surface recording artifact, and the Implant Warning that detects occlusal force overload specifically present on dental implants, which informs the clinician as to the problem forces. These robust features give clinicians the ability to efficiently diagnose and treat patients occlusally, using objective and comprehensive force and timing data. T-Scan 10 with the Novus Handpiece hardware provides the clinician the ability to manage and view patient information seamlessly by evaluating occlusal forces across both arches, identify Force Outliers and problem occlusal contacts, and view the right-left arch half to assess occlusal balance and force distribution over time.
Figure 1a. The T-Scan 10 desktop shown with a rotated 3-dimensional ForceView window, the timing table open, the active scans pane open, and a left excursive force vs. time graph displayed at the bottom of the desktop
Key Terms in this Chapter
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.
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 describe 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.
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.
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.
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.
T-Scan 10: The most modern version of the T-Scan system released in 2018, with new features and toolset, including desktop graphics that have brighter colors making for easier clinician distinction of subtle force changes displayed in its many force and timing analysis tools.
T-Scan User Clinical Competency Skills and Learning Levels to Master: Clinical competency is acquired by mastering three different levels of T-Scan Learning: Level I: Mastering proper recording skills to obtain useful T-Scan data for analysis; Level II: Mastering recorded data analysis skills through understanding all the force and timing software tools available within the software; Level III: Mastering the transfer of problematic force and timing data to the mouth, and performing precise and targeted, computer-guided intraoral corrective treatment.
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.
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.
Digital Impression Overlay (DIO): A T-Scan 10 software option that allows the clinician to view the T-Scan occlusal force and timing data superimposed over a digital impression, following the importing of an stl fils of an intraoral scanned dental arch into the Patient Record. All T-Scan software functionality available when utilizing a Digital Impression Overlay, which illustrates to the clinician a more accurate way of performing problem contact location than is possible with the generic T-Scan 10 arch model.
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.
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.