OROFACIAL PAIN AND TRADITIONAL CHINESE MEDICINE: Integrated clinical approach of acupuncture with other traditional and innovative methods for the management of pain in dysfunctional and orthodontic patients

Background: Orofacial pain (OP) is a frequent form of pain perceived in the face and/or oral cavity. It may be caused by diseases of regional structures or dysfunction of the nervous system, and it also may be induced by several dental procedures. Pain related to temporomandibular disorders (TMD) is one of the most common OP conditions, usually affecting adult population, determined by several organic and/or functional causes and characterized by a significant and complex symptomatology. Orthodontic pain is defined as OP induced by orthodontic tooth movement, and is therefore more likely afflicting paediatric population. Compared to OP related to TMD, orthodontic pain is characterized by a less intense symptomatology; it is equally commonly encountered in dentists’ clinical practice, but usually more underestimated. Acupuncture (AT) is a versatile therapeutic tool, and for this reason it is applied in various medical areas, including dentistry. Although many physiological and neurological mechanisms are still unknown, its clinical efficacy in pain therapy is widely proven. However, AT application in OP field is still lacking, and some of AT techniques and methods of points stimulation, currently used in acupuncturists practice, are completely missing in the west scientific literature. Furthermore, there is no evidence concerning the application of technologic devices, such as electrostimulation or vibration therapy, in the stimulation of acupoints for the treatment of pain in the oral and craniofacial area. Aims: The general aim of this doctoral thesis was to deepen the knowledge about the use of AT as pain management tool in OP field, investigating both the clinical efficacy of different AT techniques, including innovative technological ones, and molecular mechanisms underlying AT. The primary focus was TMD-related pain, the secondary one was orthodontic pain. Study I investigated the effects of different AT techniques in patients affected by TMD-related pain of mixed origin, including traditional and modern technologic methods of acupoint stimulation. Study II focused on the use of microsystems techniques (ear AT, abdominal AT) in TMD patients and patients affected by OP induced by fixed orthodontic appliances. Study III focused on molecular and neurological mechanisms underlying AT, investigating the salivary proteic response to ear AT in TMD myalgia patients. Methods and Results: Study I involved the application of different acupuncture methods and the use of devices for electrostimulation and vibrational therapy for treating OP in TMD patients. Two clinical studies were conducted, a prospective randomized clinical study that included TMD patients with pain of mixed origin and compared the clinical application of three different acupuncture methods (somatic AT, electroacupuncture, AT+ cupping), and a randomised double-blind placebo-controlled preliminary study, that analysed the effectiveness of at-home local vibration therapy for the management of TMD-related myofascial pain. From both studies significant improvements resulted in all types of pain treated after all the treatments applied. No significant differences were noted in the improvement of TMDs related-pain according to the different acupuncture techniques. Study II involved the application of two acupuncture microsystems therapy, abdomen and ear, respectively on treatment-resistant TMD patients and on orthodontic patients. Two different clinical studies were conducted on these different clusters of patients. All the treatments yielded to interesting results, mainly of improvement, for all the different kinds of OP treated. Study III was a pilot study and was conducted in collaboration with the Karolinska Institute of Stockholm during the period of international mobility. It consisted in the application of a protocol of ear acupuncture for the duration of 1 week, and the collection of two saliva samples before and after the treatment, on both healthy persons and patients affected by TMD myalgia. The samples were then analysed, looking for eventual differences in saliva Glutamate and Substance P fluctuation. According to the different groups analysed (real acupuncture, sham acupuncture, control group), some differences in the protein’s concentration were found, but with no significant results. All the clinical studies conducted (Study I and II), due to the COVID-19 pandemic and the relative difficulties in applying the therapy in the hospital facilities, didn’t reached the planned sample size, anyway they leaded to interesting results about the possibilities of acupuncture methods in the management of different kinds of OP. Conclusions: The three studies that form this doctoral thesis suggest that acupuncture could be a versatile and effective tool in OP field. The different methods of acupuncture applied, on both dysfunctional and orthodontic patients, lead to a general improvement of orofacial pain. Further studies are needed to confirm these clinical results and to better understand the molecular mechanisms underlying the effects of acupuncture in orofacial pain field.