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CV:
Professor emeritus Sandro Palla has authored numerous research papers on craniomandibular disorders, orofacial pain, temporomandibular joint biomechanics, TMJ imaging, estheticsand removable prosthodontics and has lectured throughout the world on these topics. He is an active member of several international pain and dental associations in some of which he served as president.He served asAssociate Editor of the Journal of Orofacial Painfrom 1997 to 2018.
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Abstract:
It is accepted that the dental occlusion has a major role in refining restorative and prosthodontic treatments to provide bilateral contacts for comfort and jaw stability. However, occlusion should not be considered anymore simply as the occlusal scheme determining the static or dynamic relationship between the dental arches or the jaw position but within a broader framework. This includes (i) the modulation of the somatosensory input from dental and other orofacial mechanoreceptors by the brain, (ii) the conscious interpretation by the patient of this input, and (iii) sensorimotor neuroplasticity.Central in this process is likely the patient’s degree of vigilance to the somatosensory stimulus, because attention increases theperception degree. Thus, patients who are hypervigilant to the oral environment are likely more sensitive to abnormal stimuli. Nevertheless, hypervigilance is likely a necessary but not sufficient cause of maladaptation as in case of symptomatic occlusal hypervigilance (occlusal dysesthesia). This requires a dysbalance between perceptual and cognitive processes along with negative affectivity and abnormal illness behaviour. The sensorimotor neuroplasticity is essential to adjust movements to an altered occlusal and/or oral condition as it happens after changing jaw position, inserting new reconstructions, altering tongue space. In some cases, however, this may lead also to maladaptive oral behaviours. Recognition that sensorimotor neuroplasticity does not always lead to a context specific adaptation of motor behaviour prevents from performing wrong and potentially harmful therapies.
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References:
- Avivi-Arber L, Sessle BJ. Jaw sensorimotor control in healthy adults and effects of ageing. J Oral Rehabil 2018;45:50-80.
- Bauer CC, Diaz JL, Concha L, Barrios FA. Sustained attention to spontaneous thumb sensations activates brain somatosensory and other proprioceptive areas. Brain Cogn 2014;87:86-96.
- Barsky AJ. Amplification, somatization, and the somatoform disorders. Psychosomatics 1992;33:28-34.
- Cioffi I, Farella M, Festa P, Martina R, Palla S, Michelotti A. Short-term sensorimotor effects of experimental occlusal interferences on the wake-time masseter muscle activity of females with masticatory muscle pain. J Oral Facial Pain Headache 2015;29:331-339.
- Hodges PW, Tucker K. Moving differently in pain: a new theory to explain the adaptation to pain. Pain 2011;152:S90-S98.
- Le Bell Y, Niemi PM, Jämsä T, Kylmälä M, Alanen P. Subjective reactions to intervention with artificial interferences in subjects with and without a history of temporomandibular disorders. Acta Odontol Scand 2006;64:59-63.
- Michelotti A, Farella M, Gallo LM, Veltri A, Palla S, Martina R. Effect of occlusal interferences on habitual activity of human masseter. J Dent Res 2005;84:644-648.
- Ostry DJ, Gribble PL. Sensory Plasticity in Human Motor Learning. Trends Neurosci 2016;39:114-123.
- Palla S, Klineberg I. Occlusion and adaptation to changes: Neuroplasticity and its implications for cognition. In: Klineberg I, Eckert, S. E(eds). Functional occlusion in restorative dentistry and prosthodontics. Edinburgh, Elsevier, 2016;45-53.
- Palla S. Adaptation and Maladaptation to occlusal changes: The role of cortical reorganization and signal amplification. Klineberg I. (edt). Proceedings of the oral rehabilitation symposium. Lucerne, Switzerland. Foundation for Oral Rehabilitation Rief W, Broadbent E. Explaining medically unexplained symptoms-models and mechanisms. Clin Psychol Rev 2007;27:821-841.