Parafunctions in Dysfunctional Syndrome of the Stomatognathic System- Literature Review

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020

PARAFUNCTIONS IN DYSFUNCTIONAL SYNDROME OF THE STOMATOGNATHIC SYSTEM- LITERATURE REVIEW

Checherita Laura Elisabeta1, Stamatin Ovidiu2*,Liana Aminov1* ,Luca Dana Elena1

1Department of Odontology, Periodontology and Fixed Prosthesis, Faculty of Dental Medicine, Grigore T. Popa University of Medicine and Pharmacy, 16 Universității Street, 700115, Iasi, Romania;

2Department of Oral-Implantology,Faculty of Dental Medicine, Grigore T. Popa University of Medicine and Pharmacy, 16 Universității Street,700115, Iasi, Romania.

Correspondig Authors *: Aminov Liana: lianaaminov @yahoo.com Stamatin Ovidiu: ovidiustamatin @yahoo.com

Abstract. The dysfunctional syndrome of the stomatognathic system(SDSS) is based on the problem of the vicious circle in which anxiety,tension,pain and probably psychological changes interact and we can conclude that stomatognathic parafunctions affect stomatognathic system, and SDSS manifests itself as a dishomeostasis, an imbalance of the mechanism of regulation of functions of this morphological and functional complex.

Keywords: bruxism,parafunctional activity,temporomandibular disorders, stomatognathic system,tensions.

Introduction resourcesand endangering his or her well- Diseases located at the level of the being” [4]. stomatognathic system are not the product The proper functioning of the of our times [1] but they help us to stomatognathic system is achieved by understand and be even more aware to dental and musculo-nervous system make correlations so that we can approach harmonious interaction. If either of these the problematic complexity from a global two systems fails, it leads to the point of view outlining an integrative stomatognathic system's motor apparatus smell and in this context the syndrome impairment. painful dysfunction can be approached as a Dysfunction is often accompanied by functional psychophysiological condition various types of parafunctions (e.g. with organic changes such as occlusal bruxism). The term „bruxism” was first disharmonies, degenerative arthritis and used in the literature in 1931 by Frohman muscle contracture that tend to achieve to refer to „dysfunctional gnashing and self-perpetuating conditions and may later brushing of the teeth” [5]. be in the teeth and joint as secondary than For instance, a general medical definition primary phenomena [2, 3]. of parafunction states that it is „disordered or perverted function'or 'abnormal or Definitions disordered function”. However, the term According to Folkman (1984), the of parafunction is mainly used in dentistry deﬁnition of stress is „a particular and its definition is more specific, but still relation-ship between the person and the is not universal. Thus, Medical Dictionary environment that is appraised by the for the Dental Professions [6] states that person astaxing or exceeding his or her parafunction is 'movements of mandible

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020 that are outside normal function, while determinants that cause dysfunction in the Mosby's Dental Dictionary refers to stomatognathic system most often the „habitual movements (e.g., bruxism, following are mentioned: traumatic clenching, and rocking of teeth using teeth occlusion, stress, wrong habits, acute and for tools) that are normal motions chronic injuries, muscles' dysfunctional associated with mastication, speech, or features and iatrogenic issues. Dysfunction respiratory movements and that result in of the masticatory motor system persisting worn facets and other problems associated for years causes over time occurrence of with occlusal trauma” [7]. Moreover, the pain symptoms or painless signs, referred parafunctions can be referred to as to as dysfunction. The main symptoms of parafunctional habits or oral habits which masticatory dysfunction are: pain during shifts the term of oral habits fully towards mandibular movements, limiting its abnormal range. In any case, even such mobility, and leaping and crackling in the specific definitions of parafunction are still TMJ. It is assumed that at least one of not very precise[5, 6]. these symptoms occurs in about 90% of Kato proposed in 2003 the following the human population [11]. definition of bruxism: „nocturnal bruxism Dysfunctional syndrome of the is a parasomnia and a parafunctional oral stomatognathic system (SDSS) manifests activity characterized on the one hand by itself as a dishomeostasis, an imbalance of the tightening of the jaws (tonic activity) the mechanism of regulation of the and/or by a phasic activity of the functions of this morphological and masticatory muscles, repetitive, which functional complex (the stomatognathic results in the grinding of the teeth” [8]. In system). It is pointed out that systemic 1990, Thorpy MJ states that nocturnal homeostasis is governed by supersystemic bruxism is a stereotypical movement factors that act at the level of the body disorder characterized by grinding or creating the conditions of a system- clenching of teeth during sleep [9] and specific homeostasis (Ca level, Mg [12, with the American Sleep Disorders 13], hormonal titration etc.) neuromuscular Association (ASDA), the International disorders, sensitivity, intoxication etc. The Classification of Sleep Disorders: etiology of joint disorders and muscle Dignostic and coding manual, [10]. dysfunctions is variate and we can The American Academy of Sleep mentions that there are a number of Medicine (AASM) conducts the hypotheses in the literature that refer to International Classification of Sleep primary etiological factors: peripheral Disorders, Westchester, pointing out that neuropathies , arterial disorders cervical „nocturnal bruxism is defined as a syndrome endocrine disorders [14, 15]. disorder of stereotypical movements The dysfunctional syndrome of the during sleep and is characterized by stomatognathic system is based on the grinding and/or clenching of teeth”. simptomatology like anxiety, tension, pain According to this, nocturnal bruxism is a and probably psychological changes sleep disorder, being included in the interact in a complexand specific way. The category of parasomnias. role of psychic stress as an etiological factor and its interpretation, some authors Parafunctions and dysfunctional draw attention that there are individual syndrome of the stomatognathic system differences in the ability to cope with Temporomandibular disorders (TMDs) stress, the psychological profile may be represent a set of muscle-skeletal disorders important in the adaptation of the associated with the masticatory system and individual [16-18].The increase of anxiety a number of symptoms. Among the and depression are the result of stress

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020 regarding the stomatognathic dysfunction significant data in this regard. It has been in the same way that they have etiological shown that bruxism may be associated significance. The ideea of stress we can with sleep phases, namely when the patient mention that it is among the external is relatively easily asleep in a rapid eye factors involved in triggering the chronic movement (REM) phase and when orofacial pain, mentioned in the dreaming may occur. During this phase of specialized studies: parafunctional habits, sleep, there are other apparently organized stress, depression, postural habits, anxiety, movements, not only of the oral-facial caffeine, sleep disorders etc [19]. region, such as swallowing and grinding of In some studies, it has been shown that the teeth, but also movements of the upper and clinical aspects of stomatognathic lower limbs, of the trunk [21, 22]. disorders are moving further and further It has also been shown experimentally that away from the orofacial sphere to spread the bruxoman's habit is not a constant throughout the body to the extremities. feature but varies from week to week, from There is a direct link between the oral month to month. Psychological stress has neuromuscular system and the global been shown to be responsible for this musculature and there is also a parallel variabilityand it also contends that bruxism between occlusal dysfunction, bruxism, depends on the state of imbalance of the damage to the masticatory muscles and the various areas of the reticulated formation, general posture of the body, implicitly the as a result of self-rejection the bruxoman's cephalic extremity. As shown in Brodie's movements appear as manifestations of a scheme, the muscle groups are in a minor autoeroticism with the most continuous antagonistic balance in order to complex clinical forms of the keep the head upright and the mandible at stomatognathic system dysfunctions. It rest. Any muscle imbalance has should be perceteded like a nocturnal implications for the function of muscular hyperactivity induced by a neighboring muscles and can cause stressful environment or so-called stomatognathic dysfunction. This explains „strangled aggression” [21]. Even if the the syndrome in people with postural etiological significance of psychological defects in the muscles of the scapular factors is accepted,there is much girdle, neck, head [20]. controversy regarding the onset or moment Inother ideas show that the Painful of action of the factor, the mode of action, Dysfunction Syndrome „is essentially a the weight of the role in maintaining the functional psychophysiological disorder dysfunctional syndrome. They aim to with organic changes that may later be in demonstrate that, aggression and anxiety the teeth and joint as secondary than would be a cause of painful joint primary phenomena” as Laskin 1969 said dysfunction, but it could be considered a in the psychophysiological theory, significant factor and it was shown that attention was drawn to implication. The increased muscle tension could be the etiology of the dysfunctional syndrome of result of a large area of interaction the stomatognathic system of the spasm of between different psychological factors the masticatory muscles is generated by and other medical one. Other authors increased psycho-emotional stress, the consider the aspect of anxiety as an stomatognathic dysfunction being etiological factor of pain and spasm, primarily a psycho-somatic disease. In motivated by the increased levels of 1985 Yemm argues that complex anxiety found in patients with movements in bruxism are centrally stomatognathic dysfunctions compared to governed. He shows that research into the the control group [23]. physiology of sleep has provided

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020

In a 1968 a literature study characterizes of bruxism: nocturnal bruxism and diurnal patients with stomatognathic dysfunction bruxism. Night bruxism is manifested by as „hostile, rigid, sarcastic”, drawing the the involuntary clenching and/or rubbing conclusion that personal or emotional of the teeth of the two arches during sleep. problems result from overloading of the Nighttime bruxism is found in both masticatory muscles and thus have a role children with deciduous or mixed teeth and in the development of some parafunctions in adults. In children it is more frequent that lead to pain [24, 25]. In an article on until the age of 12 years and is not the role of psychological factors in the accompanied by pathological changes at etiology of masticatory pain and the level of the dental-maxillary device, dysfunction, from 1982, literature being considered a way of functionalizing synthesized that: „there is convincing the dental occlusion. In case bruxism in evidence that psychological factors play a children acquires dysfunctional forms, significant role in the etiology and with the tendency to stabilize it [27]. maintenance of masticatory pain and In this case the bruxism in children dysfunction. These effects are mediated by: acquires dysfunctional forms, with the a) muscle hyperactivity; b) alteration of tendency to stabilize some pathological pain perception and tolerance; c) intermaxillary relations, the intervention is secondary symptoms; d) depression; e) necessary to eliminate or improve the personality traits; f) anxiety; g) bruxism. This is achieved in practice by parafunctional habits”. Thus in the selective grinding or by applying classification of the etiopathogenic orthopedic appliances. The most important theories realized by V. Burlui it is stated clinical signs of nocturnal bruxism are: that, subsequently The patients with dental abrasion of varying degrees stomatognathic dysfunctions are divided in depending on the age of the disease and two categories: dominant and dominated the more or less aggressive character of the persons. The mechanism of the transfer of disease, tooth grinding (sound the conflicting tension from the central manifestation), moderate myalgia, level to the muscular level follows the morning redness, and mild remodeling physiological circuit of the gamma loop, phenomena, bone of the alveolar processes with dysfunctional effects later manifested and of the temporo-mandibular joint [28, in the muscle, the temporo-mandibular 29]. joints, the dento-alveolar arches, the Daytime bruxism presents clinical periodontium, the occlusion [1]. The manifestations similar to nocturnal persistence of the etiological factor of bruxism, but myalgia has a rising intensity psychic irritation can determine the throughout the day and is deaf, organization of the aforementioned constrictive. Myalgias are exacerbated by phenomena so that the simple removal of the cold and can last for several days. the irritating factor can no longer achieve Depending on the position of the jaw the balance of the stomatognathic system versus the jaw during the episode of and restorative interventions at the level of bruxism, there are two types of the systemic elements are necessary bruxism:central bruxism encountered Laskin has the merit of drawing attention when the teeth of the two arches occur in a to the possibility that stomatognathic central position;excentric bruxism muscular hyperactivity is mediated encountered when the friction of the teeth centrally, being the result of stress [26]. of the two arches occurs in another The general used criteria for classification eccentric position [30]. of bruxism is depending on the timing of There are authors who argue that central the episode of bruxism, there are two types and eccentric bruxism are manifestations

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020 of nocturnal and diurnal bruxism and other The central nervous system plays a role in authors associate diurnal bruxism with bruxism because stimulation of the limbic central bruxism and nocturnal bruxism system can abolish the reflex activity that with eccentric bruxism [31]. opposes this pathology. Kato classifies bruxism into two forms: From the point of view of the clinical idiopathic primary bruxism; secondary manifestations it is also noted: bruxism of iatrogenic origin. The same Coronal lesion: author also mentions the differences - fractures, cracks in the spit; between the two forms of bruxism [8]. -abrasion in the form of slightly concave Idiopathic primary bruxism encompasses wear facets, localized or generalized, nocturnal bruxism, except for medical symmetrical or asymmetrical, with or causes, and diurnal bruxism due to the without preserving the vertical dimension nervous and psychic tension during the of the lower floor; day, and secondary bruxism includes -dental mobility, signs of periodontal forms of bruxism related to neurological disease if microbial factor is added; and psychiatric pathology, sleep disorders Pulpal pathology; or drug abuse [32]; ASDA and AASM Pain (dental, periodontal, muscular, joint, who have achieved International sinus, cardiac); Classification of Sleep Disorders (ICSD), Hypertrophy of masseter; divided sleep disordersinto: dyssomnias, - hyperactivity of the lifting muscles; parasomnias,sleep disorders associated - modification of the jaw movement tire; with psychiatric medical disorders,other - migraine. possible sleep disorders. According to Parafunctions are represented by an ICSD, parasomnias are classified into: abnormal activity (plus/minus- mandibular disorders due to micro- dynamics) of some muscle groups, which excitations;common parasomnias may recur and occur unconsciously .These associated with rapid eye movements parafunctions mainly target the lifting during sleep;other parasomnias. Night muscles, and the result is clinically bruxism is included in the category of manifest in the form of bruxism. other parasomnias [33]. We also note that exist simtomatology Clinically bruxism manifests itself in the like: form of a sustained contact between the -parafunctions in the form of tics: teeth for a longer period of time, strong onychophagy, biting of the lips, tongue, contraction of the lifting muscles, cheeks, suction tics, pencil suggestion, use accompanied or not by specific noises of chewing gum. The interposition of an (gnashing of teeth). It comes in two object between the arches can draw clinical forms: a)bruxism in centric attention to an undersizing of the lower relation in which under the action of floor; intense, isometric muscular contractions, -un unilateral mastication, in the case of the dento-dental contacts appear in static an obstruction or of a joint device in conditions,there is no noticeable overocclusion, can become an unconscious movement of the mandible; b) eccentric habit; bruxism in which under the action of -post playful postural attitudes (by the intense isometric and isotonic muscle viewer, with his head resting in his hands, contractions the dento-dental contacts elbows resting on his knees); appear in dynamics. The mandible -professional attitudes (shorthand, performs eccentric movements of a very violinists, trumpeters); small, noticeable amplitude. -vicious positions during sleep.

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020

All of these represent repetitive insidious positive results An experimental one-night factors (chronic microtrauma that result in treatment with clonidine, an α2 adrenergic unbalanced muscle contractions involving agonist used for treating hypertension, the muscles of the stomatognathic system attention-deficit hyperactivity disorder in (Brodie-Ackermann-Lejoyeux scheme) children and for acute alcohol or substance [1]. withdrawal syndrome has demonstrated to reduce bruxism activity by 60%, but with Effective management of primary awake significant adverse effects such as morning bruxism is challenging. Since increased hypotension, REM sleep suppression, and anxiety levels and somatization symptoms dry mouth [36-38]. In patients with have been reported in these patients, psychiatric and sleep comorbidities, the interventions such as counselling about acute use of clonazepam has been reported triggers, habits modification, relaxation to improve sleep bruxism activity together therapy or biofeedback have been with the general quality of sleep, as suggested to be appropriate. suggested by Saletu et al [39]. For different treatments in the reduction of Recently, some studies have evaluated the bruxism activity during sleep evaluated are efficacy of botulinum toxin type A as follows algorithm: (1) sleep hygiene injections into the masticatory muscles for measures combined with relaxation treating sleep bruxism. Based on techniques, (2) splint therapy, (3) PSG(placebo-controlled pharmacological therapy and (4) polysomnographic and psychometric), contingent electrical stimulation. Shim et al. found that the amplitude of the Occlusal splints have been considered as muscle contraction during bruxism events the first-line strategy for preventing dental was reduced after four weeks of injection, grinding noise and tooth wear in primary but with no changes in the rhythm or sleep bruxism. In general, the design of the number of bruxism episodes per hour of device is simple, covers the whole sleep [32]. maxillary or mandibular dental arch, and is Another kind of treatment contingent well tolerated by the patient. electrical stimulation (CES) has Mohamed et al. reported the first RCT reappeared in an attempt to reduce the evaluating amitriptyline (used during masticatory muscle activity [40] associated 7days) in a group of patients with sleep to sleep bruxism. This consists in the bruxism and temporomandibular disorder inhibition of the masticatory muscles symptoms, and found no changes in pain responsible of bruxism, applying a low- reports and in the nocturnal masseteric level electrical stimulation on the muscles muscle activities with the therapy. In when they become active, i.e. during the oposite, Lobbezzo et al. evaluated the bruxism episode [26]. acute effect of levodopa in 10 severe sleep bruxers and found a decrease in the Conclusion number of sleep-related masticatory events The importance of psychophysiological in 7 of them when compared to placebo. theory also lies in the use of therapeutic However, given the unknown clinical techniques of bio-feed-back and relevance and the lack of further research masotherapy, these belonging to a supporting its use, levodopa is not multidisciplinary approach to the treatment considered as a treatment for sleep of dysfunctional syndrome. Behavioral bruxism [34, 35]. medical orientation using bio-feed-back Other pharmacological therapies such as training and conducting stress management bromocriptine and propranolol have also sought to highlight stress by promoting been investigated, but again failed to show self-awareness and self-regulation of

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020 tension in the patient's mandator muscles the influence of stomatognathic as well as the use of drug treatment and parafunctions on stomatognathic system, occluded interceptors depending on the we can conclude that stomatognathic severity of the recorded clinical situation. parafunctions affect stomatognathic Based on the present literature review on system.

REFERENCES: 1. BurluiV, Morarasu C.Gnatologie. Editura Apollonia, Iasi, 2000. 2. American Sleep Disorders Association: International Classification of Sleep Disorders: Diagnostic and Coding Manual Rochester, Minn: American Sleep Disorders Association, 1990; Sleep Holistic. 3. The International Classification of sleep disorders, revised. Diagnostic and Coding Manual Produced by the American Academy of Sleep Medicine in association with the European Sleep Research Society, Japanese Society Sleep Research, Latin American Sleep Society- publicată în 1990-ICSD, revizuită în 1997 ICSD-R, a doua ediţie publicată în 2005-ICSD-2. 4. Folkman S. Personal control and stress and coping processes: a theoretical analysis. J. Pers. Soc. Psychol. 1984; 46: 839–52. 5. Frohman BS. Application of psychotherapy to dental problems.Dent Cosmet, 1931;73:1117–22. 6. Stedman: Medical Dictionary for Health Professions and Nursing , 2012: 1154-5. 7. Mosby: Mosby's Dental Dictionary, 2008: 508-9. 8. Kato T, Thie NM, Huynh N, Miyawaki S, Lavigne GJ. Topical Review: Sleep bruxism and the role of peripheral sensory influences. J Orofac Pain, 2003; 17(3): 191-213. 9. Thorpy MJ. International classification of sleep disorders: diagnostic and coding manual.Rochester (NY): Minnesota: American Sleep Disorders Association; 1990. 10. American Academy of Sleep Medicine . International Classification of Sleep Disorders. 3rd ed. Darien, IL: American Academy of Sleep Medicine; 2014. 11. Tanaka E, Detamore MS, Mercuri LG. Degenerative disorders of the temporomandibular joint: etiology, diagnosis, and treatment.J Dent Res, 2008;87(4):296–307. 12. Cărăușu EM, Checherita LE, Stamatin O, Manuc D. Study of biochemical level for Mg and Ca- Mg imbalance in patients with oral cancer and potentially malignant disorder and their prostetical and DSSS treatment. REV.CHIM. (Bucharest), 2016; 67(10): 2087-90. 13. Cărăușu EM, Checherita LE, Stamatin O, Albu A. Study of serum and saliva biochemical levels for Copper, Zinc and Copper-Zinc imbalance in patients with oral cancer and oral potentially malignant disorders and their prostetical and DSSS (Disfunctional Syndrome of Stomatognathic System) treatment. REV.CHIM. (Bucharest), 2016; 67(9): 1832-6. 14. Lavigne GJ, Khoury S, Abe S, Yamaguchi T, Raphael K. Bruxism physiology and pathology: an overview for clinicians. J Oral Rehabil, 2008; 35(7):476-94. 15. Mercuri LG, Olson RE, Laskin D. The specificity of response to experimental stress in patients with myofascial pain-dysfunction syndrome. J. Dent. Res., 1979; 58:1866–71. 16. Moss RA, Garret J, Chiodo JF. Temporomandibular joint dysfunction syndromes: Parameters, etiology, and treatment. Psychol. Bull., 1982; 92: 331–46. 17. Capurso U, Giacomelli P. Orofacial parafunctions in relation to the function and dysfunction of the masticatory apparatus. Minerva Stomatol., 1991; 40:619. 18. Westling L, Mattiasson A. Background factors in craniomandibular disorders: reported symptoms in adolescents with special reference to joint hypermobility and oral parafunctions. Scand J Dent Res, 1991; 99:48.

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020

19. Nilsson IM, List T, Drangsholt M. Prevalence of temporomandibular pain and subsequent dental treatment in Swedish adolescents. J. Orofac. Pain., 2005; 19: 144-150. 20. Wahlund K. Temporomandibular disorders in adolescents. Epidemiological and methological studies and a randomized controlled trial. Swed. Dent. J. Suppl., 2003; 164: 2-64. 21. Pavone BW. Bruxism and its effect on the natural teeth. J Prosthet Dent., 1985; 53(5): 692–6. 22. Carra MC, Huynh N, Morton P, Rompre PH, Papadakis A, Remise C, Lavigne GJ. Prevalence and risk factors of sleep bruxism and wake-time tooth clenching in a 7- to 17-yr-old population. Eur J Oral Sci, 2011; 119:386. 23. Alan G, Glares AB, Stephen M, Rao BA. Effects of bruxism: A review of the literature. The journal of prosthetic dentistry, 1977; 38(2):149–57. 24. Winocur E, Littner D, Adams I, Gavish A. Oral habits and their association with signs and symptoms of temporomandibular disorders in adolescents: a gender comparison. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod., 2006; 102: 482-7. 25. Greene SC, Olson ER, Laskin MD. Psychological Factors in the Etiology, Progression, and Treatment of MPD Syndrome. The Journal of American Dental Assosciation, 1982; 105(3): 443– 8. 26. Raphael KG, Janal MN, Sirois DA, Svensson P. Effect of contingent electrical stimulation on masticatory muscle activity and pain in patients with a myofascial temporomandibular disorder and sleep bruxism. J Orofac Pain, 2013; 27(1):21–31. 27. Mauno Ko¨no¨nen, Hannu S. Siirila¨. Prevalence of nocturnal and diurnal bruxism in patients with psoriasis. The journal of prosthetic dentistry, 1988; 60(2):238–41. 28. Safari A, Jowkar Z, Farzin M. Evaluation of the relationship between bruxism and premature occlusal contacts. J Contemp Dent Pract., 2013; 14(4):616–21. 29. Magnusson T, Egermark I, Carlsson GE. A longitudinal epidemiologic study of signs and symptoms of temporomandibular disorders from 15 to 35 years of age. J. Orofac. Pain, 2000; 14: 310-19. 30. Lavigne GJ, Guitard F, Rompre PH, Montplaisir JY. Variability in sleep bruxism activity over time. J. Sleep Res, 2001; 10: 237–44. 31. Ioniţă S, Petre A. Ocluzia Dentară, Editura Didactică şi Pedagogică, RA Bucureşti. 2003; 198- 200. 32. Shim YJ, Lee MK, Kato T, Park HU, Heo K, Kim ST. Effects of botulinum toxin on jaw motor events during sleep in sleep bruxism patients: a polysomnographic evaluation. J Clin Sleep Med, 2014; 10(3):291–8. 33. American Academy of Sleep Medicine. Chicago: AASM; 2001. International Classification of Sleep Disorders: Diagnostic and Coding Manual. 34. Wolff HG. The Nature of bruxism: A New Diagnostic Approach. J Dent. Med. Stom., 2001; 10: 979-86. 35. Lobbezoo F, Lavigne GJ, Tanguay R, Montplaisir JY. The effect of catecholamine precursor L- dopa on sleep bruxism: a controlled clinical trial. Mov Disord., 1997; 12(1):73–8. 36. Mohamed SE, Christensen LV, Penchas J. A randomized double-blind clinical trial of the effect of amitriptyline on nocturnal masseteric motor activity (sleep bruxism). Cranio., 1997; 15(4):326– 32. 37. Lavigne GJ, Soucy JP, Lobbezoo F, Manzini C, Blanchet PJ, Montplaisir JY. Double-blind, crossover, placebo-controlled trial of bromocriptine in patients with sleep bruxism. Clin Neuropharmacol., 2001; 24(3):145–49.

Romanian Journal of Medical and Dental Education Vol. 9, No. 1, January - February 2020

38. Huynh N, Lavigne GJ, Lanfranchi PA, Montplaisir JY, de Champlain J. The effect of 2 sympatholytic medications—propranolol and clonidine—on sleep bruxism: experimental randomized controlled studies. Sleep, 2006; 29(3):307–16. 39. Saletu A, Parapatics S, Saletu B, Anderer P, Prause W, Putz H et al. On the pharmacotherapy of sleep bruxism: placebo-controlled polysomnographic and psychometric studies with clonazepam. Neuropsychobiology, 2005; 51(4): 214–25. 40. Forna NC. Protetică Dentară, Vol. I si II, Ed. Enciclopedică, Iași, 2011.