Is there a real consensus on occlusion or only biased opinions?

Editorial Commentary^[1]

The Journal of Prosthodontics should be applauded for its decision to compile a special issue devoted to the topic of “Occlusion” in order to clarify or dispel some ongoing controversies. However, the special issue did not contain any mention of the latest occlusion technologies (e.g. T-Scan) within the entire issue, which was very disappointing. During the past 37 years, there have been hundreds of papers published about the T-Scan’s Measured Occlusion, all of which were completely excluded from this special issue, which exudes a very strong editorial bias against the computer-era dental discipline of Measured Digital Occlusion, while effectively obfuscating the many advances in occlusion the T-Scan technology has helped evolve. Although many of the cited publications within the individual articles’ reference lists referred to the technologies that followed jaw movements, measured maximum clenching muscle activity levels, or imaged TM joints radiographically, only the excluded T-Scan 10 technology (Tekscan, Inc. S. Boston, MA, USA) measures occlusal contact forces and contact timing sequences between intercuspating and excursing teeth. To promote a Consensus on Occlusion issue without including tooth and occlusal contact force and timing research gathered objectively between the teeth before making consensus statements about occlusal function, seems more than misguided. After all, this was an issue completely devoted to dental occlusion, which directly involves teeth. Moreover, including T-Scan research would most likely have substantially altered some of this occlusion issue’s consensus conclusions.

The Measured Digital Occlusion era began in 1984 with the first design of the T-Scan technology. Over the past 37 years, the T-Scan technology has undergone continuous hardware, recording sensor, and software improvements, such that today’s T-Scan version 10 is a precise, objective, occlusal force and timing clinical adjunct¹ that has published research-based applications in Prosthodontics, Dental Implants, TMD, Posturology, Orthodontics, Periodontics, Occlusal Diagnosis, Aesthetic Dentistry, Tooth Hypersensitivity and most importantly, for obtaining high-precision during occlusal adjustment. When combined with other biometric dental technologies such as Electromyography (BioEMG III, Bioresearch Assoc., Milwaukee, WI), the T-Scan 10 has found answers to many occlusal controversies that have plagued the traditional, but highly-subjective occlusal methods. A recent systematic review published in the European Journal of Prosthodontics and Restorative Dentistry,¹ reported “much scientific evidence supports the use of T-Scan, as it measures relative occlusal forces and timing objectively, accurately, and repeatably.”

An example how this missing T-Scan based research would have likely altered their consensus, while helping readers to better understand the longstanding misperceived concerns over mediotrusive contacts (Walton, T. Mediotrusive Occlusal Contacts: Best Evidence Consensus Statement pp. 43-51), can be seen with the exclusion of a number of TMD patient treatment studies where T-Scan was synchronized to electromyo-graphy.^2–4 Simultaneous T-Scan/BioEMG III masticatory muscle recordings^, have repeatedly shown that mediotrusive (balancing or non-working) contacts to be far less damaging to the Stomatognathic System, cause far less TMD problems, and cause far less occlusal wear and tooth hypersensitivity than for laterotrusive contacts (working side group function contacts). This is because laterotrusive contacts create extremely high levels of muscle activity when compared to the measured muscle activity levels that mediotrusive contacts generate.^2,3 Laterotrusive contacts are therefore far more damaging to teeth, muscles, and the TM joints than are mediotrusive contacts. Further, although both mediotrusive contacts and laterotrusive contacts are biomechanically undesirable contacts, they act very differently neurologically. Many research papers using T-Scan^2–11 have shown that laterotrusive contacts cause most of the occlusion-related symptoms dentists attempt to resolve, often by treating mediotrusive contacts instead of laterotrusive ones because unmeasured occlusal theory promotes this incorrect belief. Had any of the T-Scan 10/BioEMG III based research been included in this mediotrusive article, the authors would have been forced to increase their emphasis on the important causative neurologic aspects of laterotrusive contacts, while educating readers that working side group function contacts are far more problematic than are mediotrusive contacts.

Withheld from the JOP reader, is the fact that the T-Scan occlusal force and timing data sets used in many previously published human occlusal adjustment studies since early 1990s, have improved human chewing,^2,3 reduced cold sensitive teeth,⁷ improved occlusal adjustment outcomes,¹¹ and reduced chronic TMD muscular symptoms.^2–6,8–10 This absence of T-Scan research suggested to the readers that occlusal science has not advanced in the past 37 years, when it has definitively evolved because of the T-Scan technology. And, most importantly, patients have markedly benefited from T-Scan.^2–11

If the authors and editors of this Occlusion Issue justified their exclusion of T-Scan research with the "sometimes-advocated opinion" that the T-Scan sensor is “too thick,” the 100 mm thick Novus High Definition sensor (Tekscan Inc., S. Boston, MA USA) is well within the range of many commonly used static interarch occlusal indicators that are not questioned for their accuracy, despite research showing static occlusal indicators are inaccurate, are highly subjective to use, and have no force level measurement or time-measurement descriptive capabilities.^1,12–15 The 100 µm T-Scan sensor thickness is a positive sensor attribute that protects sophisticated printed electronic components within a flexible and compressible Mylar substrate. Validity studies of the T-Scan HD sensor were performed in 2006, 2010, 2012, and in 2014,¹ which indicated the HD sensor can repeatedly measure differing relative occlusal contact force levels in multiple locations simultaneously within the dental arch. To date, no published paper has disproved the validity of the T-Scan HD sensor, and no scientific evidence has been published that shows sensor thickness as a drawback on its recording capabilities or accuracy.^1,12–15

The JOP therefore had no valid basis to exclude T-Scan research from their Occlusion Issue, when many of the included articles consensus conclusions were likely based upon highly subjective and unmeasured occlusal indicators. These T-Scan research omissions clearly bring into question most of the consensus conclusions this Occlusion issue put forth. By withholding 37 years of T-Scan Measured Digital Occlusion research from this consensus, the JOP readership was denied the opportunity to learn how the Measured Occlusion approach, using a computer-guided technique, has dramatically changed occlusion very much for the better.

Respectfully Submitted,

Hans van Pelt, Dr., PhD
Sarah Qadeer, BDS, MSD
Robert B Kerstein, DMD

Potential conflicts

The 3rd author is a Clinical Consultant for Tekscan, Inc. S. Boston, MA, USA, but receives no compensation for the sales of any Tekscan, Inc. products.