Bruxism and its management

prosthodontic approach for bruxism

1. BRUXISM AND IT’S MANAGEMENT PRESENTER-DR MEGHA SABHARWAL PRECEPTOR-DR KASHINATHA SHETTY Date- 17/04/2020

2. CONTENTS Introduction. Definition. Classification Etiology. Clinical Implications. Risk factors Diagnosis. Investigations Management Case Studies

3. According to GPT 9, bruxism is defined as “ the parafunctional grinding of the teeth; an oral habit consisting of involuntary rhythmic or spasmodic non-functional gnashing, grinding, or clenching of teeth, in other than chewing movements of the mandible, which may lead to occlusal trauma” It is noted as the commonest of the many parafunctional habits of dento facial system. Bruxism activity is of major concern for the dentists as it leads to tooth wear and damage, restoration fractures, temporal headache and other temporomandibular disorders . The prevalence range is from 8-31% in the general population and 14-20% in children

4. INTRODUCTION Activities of the masticatory system can be divided into two types: Functional, which includes chewing, speaking, and parafunctional , which includes clenching or grinding of the teeth (referred to as bruxism ). Parafunctional activity is also known as muscle hyperactivity . ‘ Bruxism ’ originates from the Greek word brychein ,meaning to ‘gnash the teeth’. An early and common definitionof bruxism was thus ‘‘gnashing and grinding of the teeth for non-functional purposes’’

5. CLASSIFICATION Bruxism is classified based on: 1) Time of occurrence a. Awake bruxism b. Sleep bruxism (SB) c. Combined bruxism 2) Aetiology a. Primary, essential or idiopathic bruxism : For which no apparent cause is known. b. Secondary bruxism : Secondary to diseases (coma, icterus , cerebral palsy), medication (e.g., antipsychotic and cardioactive medication) and drugs (e.g., amphetamines, cocaine).

6. 3) Motor activity type a. Tonic: Muscular contraction sustained for more than two seconds. b. Phasic : Brief, repeated contractions of the masticatory musculature with three or more consecutive bursts of electromyographic activity that last between 0.25 and two seconds apart. c. Combined: Alternating appearance of tonic and phasic episodes. Approximately 90% of the episodes of SB are phasic or combined, unlike in awake bruxism , where episodes are predominantly tonic . 4 ) Status of bruxism a. Past b. Current or present

7. ETIOLOGY The etiology of bruxism is uncertain, but the hypotheses fall into four major categories: 1. Local factors 2. Neurological factors 3. Medications 4. Psychosocial factors Local factors Bruxism has been interpreted as an automatic reaction of the body to occlusal interferences with the purpose of eliminating them by grinding. Even though there are some data suggesting that occlusion affects muscle activity leading to parafunctions , most of the studies seem to deny this correlation . Neurological factors Some neurological pathologies may be associated with parafunctional oral activity such as - Dyskinesias , Parkinson’s disease, and other extrapyramidal disorders .

8. Medications Several medications that have been shown to elicit bruxism : Amphetamines, L-dopa, fenfluramine , phenothiazine , neuroleptics , selective serotonin reuptake inhibitors ( SSRls ), Antipsychotic agents which frequently cause dyskinesias : fluphenazine , haloperidol loxapine , molindone , perphenazine , pimozide , thiothixene , trifluoperazine and Recreational drugs (heroin, cocaine, ecstasy, marijuana, (“crack”, LSD, methadone). Psychosocial factors This includes anxiety, stress and characteristics of personality.

9. CLINICAL IMPLICATIONS ACTIVITIES NORMAL PARAFUNCTION DIRECTION OF APPLIED FORCE VERTICAL HORIZONTAL/LATERAL MANDIBULAR POSITION STABLE /CENTRIC OCCLUSAL POSITION UNSTABLE/ECCENTRIC POSITION MUSCLE ACTIVITY RYTHMIC CONTRACTION AND RELAXATION SUSTAINED MUSCLE CONTRACTION NEUROMUSCULAR REFLEXES PROTECTION FROM REFLEXES PRESENT ABSENT OR THRESHOLDS ARE Reddy SV, Kumar MP, Sravanthi D, Mohsin AH, Anuhya V. Bruxism : a literature review. J Int Oral Health. 2014; 6(6):105-9.

10. SIGNS 1. Abnormal tooth wear and occlusal trauma 2. Tongue & cheek indentation 3. Linea alba along the biting pane 4. Gum recession 5. Increase in muscle activity (this is recorded by the polysomnography ) 6.Presence of masseter muscle hypertrophy on voluntary contraction SYMPTOMS 1. Grinding of the teeth accompanied by a characteristics sound that may even awaken the bruxers bed partner 2. Headache (especially in the temporal zone when the patient wakes up in the morning) 3. Pain, Clicking or locking of temporomandibular joint 4. Pain in the masticatory and cervical muscles 5. Tooth or teeth hypersensitive to cold air or liquid 6. Excessive tooth mobility 7. Poor sleep quality ,tiredness

11. Risk Factors Age : Bruxism is more common in young children and noted to decrease by adulthood. Stress : Increased stress and anxiety can cause bruxism . Personality: Aggressive, competitive and hyperactive type of behaviour and personality can increase the chance of teeth grinding. Family history : Sleep bruxism tends to give a family history, other members also may have teeth grinding or a history of it. Medications and habits : Certain antidepressants can result in bruxism as an uncommon side effect. Habits like smoking, tobacco chewing, drinking caffeinated beverages may increase the risk of bruxism . Other factors - Bruxism can be associated with medical problems like epilepsy, sleep related disorders, dementia, parkinson’s disease and gastroesophageal reflux disorder.

12. DIAGNOSIS Diagnosis of bruxism is based particularly on case history, clinical evaluation followed by investigations. Icludes questionnaires Self reports to assess presence and absence of bruxism is convenient for both clinicians and researchers.

13. OTHER METHODS Clinical evaluation Tooth Wear Facets of Intra-oral Appliance Assessment of bruxism activity Measurement of bite force

14. Clinical evaluation Tooth Wear Tooth wear is considered to be analogous to bruxism . Tooth wear is a cumulative record of both functional and parafunctional activities and various factors such as age, gender, diet and bruxism are associated with tooth wear. Several studies have demonstrated a positive relationship between tooth wear and bruxism . Major disadvantage with tooth wear is that it neither proves ongoing bruxism nor static tooth clenching. Tooth-Wear Index is used to the rank persons with regard to incisal and occlusal wear.

15. Facets of Intra-oral Appliance Repetitive wear pattern on the occlusal splint has been reported with wear facets on full-arch acrylic resin splints, which reappeared in the same location with a similar pattern and direction, even after adjustment of the splints. Hence intra oral appliances may be used to detect bruxism .

16. Assessment of bruxism activity The Bruxcore Bruxism -Monitoring Device (BBMD) is an intra-oral appliance that was introduced as a device for measuring sleep bruxism activity objectively and the Bruxcore plate evaluates bruxism activity by counting the number of abraded microdots on its surface and by scoring the volumetric magnitude of abrasion. The major disadvantage with this method is that it is difficult to count the number of missing dots with good precision

17. Measurement of bite force Takeuchi et al. developed a recording device for sleep bruxism , an intra-splint force detector (ISFD) , which uses an intra-oral appliance to measure the force being produced by tooth contact onto the appliance. The force is detected using a thin deformation-sensitive piezoelectric film, which is embedded 1-2 mm below the occlusal surface of the appliance.

18. Investigations Polysomnography (sleep laboratory) This offers a highly controlled recording environment wherein sleep disorders can be ruled out and sleep bruxism can be discriminated from other orofacial activities that occur during sleep. Physiological changes related to sleep bruxism ( e.g tachycardia and sleep-stage shift) can also be monitored. These recordings for sleep bruxism generally include electroencephalogram, electromyography electrocardiogram and thermally sensitive resistor (monitoring air flow) signals along with simultaneous audio-video recordings.

19. One major limitation is that a change in the environment for sleep may influence the actual behaviour of bruxism . Another is the expense as multiple night recording is to be taken for the occurrence of sleep bruxism as it varies over a number of nights .

20. Masticatory Muscle Electromyographic Recording Sleep bruxism activity is assessed based on EMG (Electromyography) activity in the masticatory muscles ( masseter and/ or temporalis ) . Since 1970s, sleep bruxism episodes were measured over an extended period in patient’s homes with the use of battery-operated EMG recording devices which can measure masticatory muscle activity more minutely, i.e. the number, duration and magnitude of bruxism events. A miniature self-contained EMG detector-analyser (Bite-Strip ) was developed as a screening test for moderate to high level bruxers wherein the number of bruxism events can be objectively estimated by simply attaching it to the skin over the over the masseter muscle .

21. Recently, a miniature self-contained EMG detector– analyser with a biofeedback function ( grindcare , medotech , denmark ) was developed as a detector and biofeedback device for sleep bruxism . It works by the online recording of EMG activity of the anterior temporalis muscle, online processing of EMG signals to detect tooth grinding and clenching and also biofeedback stimulation for reducing sleep bruxism activities.

22. MANAGEMENT

23. Behavioural modification Psychoanalysis, hypnosis, meditation, sleep, hygiene measures with relaxation techniques and self- monitoring have been considered for the treatment of bruxism . The treatment of sleep bruxism usually begins with counselling of the patient with respect to the sleep hygiene. It includes to instruct the bruxer to stop smoking and drinking of coffee or alcohol , to limit the physical or mental activity before going to bed, and to ensure good bedroom conditions like quiet and dark

24. Pharmacological therapy Certain drugs have paralytic effect on the muscles, by inhibiting acetylcholine release at the neuromuscular junction (NMJ) therby decreasing bruxism activity in severe cases like coma, brain injury etc. In a study, botox injections over a period of 20 weeks showed decrease in bruxism activity in 18 subjects. This study suggested that botulinum toxin inhibited the release of acetylcholine at NMJ . Shim et al. found that the amplitude of the muscle contraction during bruxism events was reduced after 4 weeks of injection, but with no changes in the rhythm or number of bruxism episodes per hour of sleep. Tan EK, Jankovic J. Treating severe bruxism with botulinum toxin. J Am Dent Assoc. 2000; 131:211-216 Jong Sup Shim et al Effect of muscle activity and botulinum toxin dilution volume on muscle paralysis Developmental Medicine & Child Neurology 2003, 45: 200–206

25. Another pharmacologic approach involves the use of botulinum toxins in the treatment of bruxism . The clinician injects botulinum toxins into the masticatory muscles that are triggered with bruxism , including the temporalis and masseter . Study results indicate that the use of this treatment can cause some bruxism -related muscle pain to subside and may reduce bruxism events Lang R, White PJ, Machalicek W, et al. Treatment of bruxism in individuals with developmental disabilities. Res Dev Disabil . 2009;30(5):809-818

26. Lobbezoo and colleagues conducted a thorough systematic review of the treatment modalities for both waking and sleeping bruxism . They summarized the best approach as the “triple-P” approach: plates, pep talk, and pills. Specifically, they referred to stabilization splints, counseling , and short-term pharmacotherapy. Lobbezoo F, van der Zaag J, van Selms MK, Hamburger HL, Naeije M. Principles for the management of bruxism . J Oral Rehabil . 2008;35(7):509-523.

27. Biofeedback Biofeedback works on the principle that “ bruxers can unlearn their behaviour when a stimulus makes them aware of their adverse jaw muscle activities”. Mittelman described an EMG technique that provides the daytime bruxer with auditory feedback from his/her muscle activity letting him know the degree of muscle activity or relaxation that is happening. Nissani used a taste stimulus to awaken the patient, in case of sleep bruxism .

28. In recent years, contingent electrical stimulation (CES) has appeared in an attempt to reduce the masticatory muscle activity associated to sleep bruxism . The rationale during the bruxism episode is RATIONALE INHIBITION OF MUSCLES ELECTRICAL STIMULATION

29. Experimental studies have used CES in patients with signs and symptoms of sleep bruxism and myofascial pain, and found a reduction of the EMG episodes per hour of sleep while using CES, but with no changes in pain and muscle tension scores. Svensson P. Effect of contingent electrical stimulation on jawmuscle activity during sleep: a pilot study with a randomized controlled trial design. Acta Odontol Scand. 2013; 71(5):1050-62 Conti PC, Stuginski-Barbosa J, Bonjardim LR, Soares S, Svensson P. Contingent electrical stimulation inhibits jaw muscle activity during sleep but not pain intensity or masticatory muscle pressure pain threshold in self-reported bruxers : a pilot study. OralSurg Oral Med Oral A review of current concepts in bruxism -diagnosis and management. Nitte university journal of health sciences. 2014, 4(4).

30. Occlusal Therapy These splints have different names such as occlusal bite guard, bruxism appliance, bite plate, night guard, occlusal device. They are classified into hard splints and soft splints. Hard splints are preferred over soft splints because soft splints are difficult to adjust and hard splints are effective in reducing the bruxism activity . A study compared occlusal splints versus a medication doses gabapentin , and found that both treatments reduced similarly the muscle activity associated with sleep bruxism after 2 month of therapy. Okeson JP. The effects of hard and soft occlusal splints on nocturnal bruxism . J Am Dent Assoc. 1987; 114:788-791. Madani AS, Abdollahian E, Khiavi HA, Radvar M, Foroughipour M, Asadpour H et al. The efficacy of gabapentin versus stabilization splint in management of sleep bruxism . J Prosthodont . 2013; 22(2):126-31.

31. Classification of occlusal splints Okeson 1) Muscle relaxation appliance/ stabilization appliance used to reduce muscle activity 2) Anterior repositioning appliances/ orthopedic repositioning appliance 3) Anterior bite plane 4) Pivoting appliance 5) Soft/ resilient appliance Dawson 1) Permissive splints / muscle deprogrammer 2) Directive splints/ non-permissive splints 3) Pseudo permissive splints (e.g. Soft splints, Hydrostatic splint)

32. Hard acrylic occlusal splint appliances Hard acrylic occlusal splint appliances may be indicated in patients who require protection of their teeth from the further damage, to reduce tooth grinding sounds during sleep, or to manage concomitant orofacial pains (example masticatory muscle myalgia ). Many authors recommend canine- protected occlusion to disocclude the posterior teeth during eccentric movements.

33. Soft vinyl mouth guards Soft mouth guards are generally not durable and are contraindicated for long term use. More than 50% of patients with soft mouth guards show increased masseter EMG activity during sleep. A third variation of material known as dual laminated , as its occlusal surface consists of hard acrylic resin and the tooth-borne surface consist of a soft material. This produces an occlusal appliances with advantages of a soft material (fitting well and providing comfort for the supporting teeth),and an adjustable occlusal surface of the hard acrylic resin.

34. Studies on efficacy of hard splint versus soft splint Hard acrylic resin occlusal appliances have several advantages over the soft appliances; hardness and resistance of the acrylic resin enable Easy and quick adjustments, easy repair, the fit of a hard acrylic resin is more accurate, methods of fabrication is more reliable and greater longevity , more color stable , less food debris accumulation and more durable than that of the soft version. In contrary, the adjustment of soft material is more difficult and often results in a less adequate occlusal scheme. And these appliances are more susceptible to wearing that in turn result in occlusal changes.

35. FABRICATION OF OCCLUSAL SPLINT Clinical Steps 1:• An impression of both the maxillary and mandibular arches were made with irreversible hydrocolloid material and poured with type III dental stone to obtain diagnostic casts to be mounted using type II dental plaster in a semi adjustable articulator following a face bow transfer and centric relation bite record . A preexisting record of centric relation and centric occlusion of the patient need to be made before treatment to avoid change in occlusion after therapy

36. Laboratory steps : • The face bow record helps in mounting of the maxillary cast where as the centric relation bite record help in mounting of the mandibular cast in relation to the maxillary cast in the articulator [Fig-1]. This relates exactly to that of the patient’s existing jaw occlusion relation . After mounting, the maxillary cast was detached from the articulator to do surveying procedure using a dental surveyor in order to determine the height of contour of the teeth and reattached back. The vertical height of the articulator with mounted casts was increased by 1mm and locked in this new incisal guide position to provide interocclusal space between the posterior teeth . The undercuts are blocked out around the maxillary teeth below the survey line exposing about 2mm on buccal surface and 3-4mm on palatal surface [Fig-2].

37. Separating media is applied on the maxillary teeth up to the block out, followed by dispensing of self cure clear acrylic polymer-monomer slowly by sprinkle on method to get adequate thickness of the splint [Fig-4] In between, the articulator is closed often to ensure firm seating of the incisal guide pin on the incisal guide table. Once set, the acrylic splint is removed carefully from the maxillary cast, finished and polished in a regular manner. Rechecking of finished and polished occlusal acrylic splint was done by closing the articulator to verify whether the mandibular centric (functional) cusp tips made contact with the occlusal surface of the splint.

38. Clinical step 2:• Insertion of customized self cure clear acrylic maxillary occlusal splint is completed with minor intraoral adjustments . Post-insertion instructions are given and the follow-up visits till total satisfactory results with reduced symptoms are found in the patient. The recommended protocol after insertion of the splint is that the patient need to visit the prosthodontist for adjustments at 24 hrs, 3 days, 7 days, 14 days, 21 days and 1 month intervals .

39. Improvement Due to Splint 1) Occlusion on the splint changes , with absence of contacts especially at the anterior region 2) after removal of the splint at morning , there is difficulty to achieve occlusion in MI (The difficulty of occlusion demonstrates the difference between the arc of closure in MI and the arc of closure in the neuromuscular balanced position. ) 3 ) The splint increasedthe awareness of parafunction .(theory of cognitive perception.Occlusalcoverage and the dental contacts on the splint seem to be important factors that, combined to the change in tonguepositioning , increase the patient’s awareness) 4) Improved pain relief ( the efficacy of occlusal splint to reduce the electromyographic activity at rest,maximum clenching and during nighttime parafunctional activity) 5) The absence of anterior contacts on the splint at the follow-up visits suggests mandibular retrusion , which occurs due to relaxation of the inferior lateral pterygoid muscles, which are responsible for anterior condylar movement. Raphael KG, Marbach JJ, Klausner JJ, Teaford MF, Fischoff DK. Is bruxism severity a predictior of oral splint efficacy in patients with myofascial face pain? J Oral Rehabil . 2003;30(1):17-29. Roark AL, Glaros AG, O’Mahony AM. Effects of interocclusal appliances on EMG activity during parafuncional tooth contact. J Oral Rehabil . 2003;30(6):573-7.

40. This study compared occlusal splints fabricated in centric relationand maximum intercuspation in muscle pain reduction of TMD patients. Twenty patients with TMD of myogenous origin andbruxism were divided into 2 groups treated with splints in maximum intercuspation (I) or centric relation (II). electrognathographic and electromyographic examinations were performed before and 3 months after therapy. There was a remarkable reduction in pain symptomatology , without statistically significant differences (p>0.05) between the groups.

41. There were no significant differences (p>0.05) in the electromyographic activities at rest after utilization of both splints. In conclusion ,both occlusal splints were effective for pain control and presented similar action. The results suggest that maximum intercuspation may be used for fabrication of occlusal splints in patients with occlusal stability without large discrepancies between centric relation and maximum intercuspation .

42. In this report, computer-based design and production of occlusal splints was described . In order to eliminate the inherent variabilities associated with current splint-fabrication methods. The digital process provides – quantitative control over articulation and splint design , and produces splints with continuously smooth occlusal surfaces. Stone casts are laser scanned , and custom software is used to articulate and design flat-plane and full-coverage splints with guidance ramps. Splints are produced by milling excess acrylic placed over stone casts. Clinically, digital splints reduce the average time needed for placement because intraoral equilibration is minimized. American Journal of Orthodontics and Dentofacial Orthopedics Volume 133, Number 4, Supplement 1

43. CAD/CAM splints for the functional and esthetic evaluation of newly defined occlusal dimensions Modern production technologies now allow the use of tooth- colored occlusal splints made of polycarbonate , whose quality and material properties are quite distinct from those of conventionally manufactured splints made of transparent polymethyl methacrylate (PMMA). These materials, produced under standardized polymerization conditions, are extremely homogenous, which provides benefits such as a greater accuracy of fit by eliminating the polymerization shrinkage, greater long-term stability of shapes and shades, better biocompatibility, less wear, and a more favorable esthetic appearance. In addition, tooth- colored polycarbonate splints can be fabricated very thin without significantly increasing the fracture risk, thanks to the flexibility of the material . The improved wearing comfort combined with acceptable esthetics result in significantly improved patient compliance in terms of a "23-hour splint.”

44. Effect of bruxism on prosthetic restorations The most common mechanical failures reported in case of prosthetic restorations on natural teeth included loss of retention and fracture of material and the occurrence of such failures is greatest in patients with bruxing habits. Metal or metal–ceramic restorations(or restorations with high nobel content ) seem to be the safest choice in cases of high load conditions, although under extreme conditions, there is no material that will last for too long. Due to the risk of chipping of ceramic veneers in metal–ceramic restorations , gold– acrylic FDPs for heavy bruxers were preferred.

45. Clinical studies published on wear of materials in bruxism patients indicate minimal differences in wear resistance of gold and ceramic materials, whereas resin-based materials showed times more substance loss than gold or ceramics. Zirconia , which is the present material of esthetics and strength, have demonstrated improved mechanical properties in laboratory studies and hence may be promising in the treatment of bruxism related tooth wear . However, a systematic review of zirconia FDPs has shown that there are complications when the material is used clinically.

46. Effect of bruxism on implant restorations In a prospective 15- year follow-up study of mandibular implant-supported fixed prostheses, smoking and poor oral hygiene had a significant influence on bone loss, whereas occlusal loading factors such as bruxism , maximal bite force and length of cantilevers were of minor importance. Although bruxism was included among risk factors, and was associated with increased mechanical and/or technical complications, it had no effect on implant survival. Several studies have indicated that patients with bruxism have a higher incidence of complications on the superstructures of both of fixed and removable implant-supported restorations .

47. The effect of bruxism on treatment planning for dental implants Excessive force is the primary cause of late implant complications. One viable approach is to increase the implant-bone surface area. Additional implants can be placed to decrease stress on any one implant, and implants in molar region should have an increased width. Use of more and wider implants decreases the strain on the prosthesis and also dissipates stress to the bone, especially at the crest. The additional implants should be positioned with intent to eliminate cantilevers when possible. . Misch CE . The effect of bruxism on treatment planning for dental implants. Dent Today.  2002 Sep;21(9):76-81 .

48. Greater surface area implant designs made of titanium alloy and with an external hex design can also prove advantageous. Proper established anterior guidance in mandibular excursions further decreases force and eliminates or reduces lateral posterior force. Metal occlusal surfaces decrease the risk of porcelain fracture and do not require as much abutment reduction, which in turn enhances prosthesis retention. Night guards designed with specific features also are a benefit to initially diagnose the influence of occlusal factors for the patient, and as importantly, to reduce the influence of extraneous stress on implants and implant-retained restorations.

49. The consequences of nocturnal parafunctional habits may be prevented by acrylic resin night guards A hard stabilization splint for nightly use (night guard) contributes to optimally distributing and vertically redirecting forces that go with nocturnal teeth grinding and clenching . A night guard that promotes even occlusal contacts around the arch in centric-related occlusion can be helpful to prevent fractures of implant prostheses.

50. In current clinical practice, porcelain has become the primary occlusal material for single-tooth and partial fixed implant prostheses . It is generally agreed that ceramic occlusal surfaces provide superior esthetics and wear resistance Regarding full-arch fixed prostheses on implants, metal ceramic prostheses are sometimes presented in clinical reports, but in many centers acrylic resin teeth continue to be the material of choice. Although there is no evidence regarding the preferred restorative materials in implant prosthesis for patients with bruxism , some clinicians prefer metal restorations and not porcelain to protect the implant prostheses in patients with bruxism , especially for second molar teeth in the maxilla . Recently, investigators demonstrated zirconia as a new dental implant material . Osamu Komiyama,Frank Lobbezoo , Antoon De Laat Clinical Management of Implant Prostheses inPatients with Bruxism International Journal of Biomaterials volume 2012

51. Effect of bruxism on dentures It is considered, clinical experience indicates that bruxism is a frequent cause of complaint of soreness of the denture-bearing mucosa. In a similar way, heavy bruxism may have deleterious effects on the residual dentition and the denture-bearing tissues in patients with RPDs, although this has not been systematically studied.

52. A study mentioned the management of four patients with severe sleep bruxism , and who were using conventional RPDs. Each patient was provided with a splint-like RPD, called a night denture, and followed-up for 2–6 years using the night denture. The study concluded that the night denture appeared to be effective in managing problems related to sleep bruxism in patients with RPDs. Delivery of an inexpensive acrylic night denture is a practical approach to minimize the unfavorable effects of sleep bruxism in these patients, which include progression of tooth attrition, uncomfortable feeling or pain inthe remaining teeth upon waking, and increased tooth mobility . Baba K, Aridome K, Pallegama RW. Management of bruxism -induced complications in removable partial denture wearers using specially designed dentures: A clinical report. Cranio . 2008; 26:71-6.

53. resin occlusal coverage over the remaining anterior teeth with a resin base and increased the vertical dimension, resulting in a gap of 3 mm between the upper and lower incisal edges.

54. Clinical examination revealed that the tooth contact occurred only at the left premolar region between the copings and the opposite teeth in the absence of the denture.

55. CASE- AWAKE BRUXISM COMPLIANCE? SPEECH & SALIVARY FLOW?

56. CASE STUDIES A case series survey by Ingerslev ,on a cohort of 366 children aged 6 to 16 over a period of 4 years documented the efficacy of functional therapy (soft and hard bite-splints) on reducing the SB signs and symptoms. The authors reported that about 60% of the patients presented with symptom reduction, while 34% were essentially symptom-free at the conclusion of the treatment. It is plausible that SB that is related to a structural problem, including airway obstruction due to enlarged tonsils, enlarged adenoids, narrow maxillary arches, mouth breathing, and retrognathic mandible can be managed by treatments that solve these airway obstructions in the nasopharynx , oropharynx , and hypopharynx Treatments of sleep bruxism in children: A systematic review and meta-analysis Gaetano Ierardo , Marta Mazur, Valeria Luzzi , Francesca Calcagnile , Livia Ottolenghi & Antonella Polimeni Journal of Craniomandibular and sleep practice

57. The first systematic review with meta-analysis assessing the available evidence of SB therapy in children, showed that pharmacotherapy with hydroxyzine is the most effective treatment in reducing both symptoms and signs of SB over a period of four weeks in a total of 28 subjects. Benzodiazepine administration and the usage of Melissa officinalis (lemon balm /balm mint) showed a lower effect in studies . Although, among the pharmacological therapies on drugs such as hydroxyzine , flurazepam , and Melissa Officinalis , hydroxyzine showed the most effective treatment available but still has shown a weak evidence of a possible efficacy on reducing SB symptoms and signs Ghanizadeh A,Zare S. A preliminary randomised double-blind placebo-controlled clinical trial of hydroxyzinefor treating sleep bruxism in children. J Oral Rehabil . 2013 ;40(6):413–417. Bortoletto C, Cordeiro Da Silva F, Salgueiro Mda C, et al. Evaluation of electromyographic signals in childrenwith bruxism before and after therapy with Melissa officinalis L-a randomized controlled clinical trial.J Phys Ther Sci. 2016 ;28(3):738–742.

58. Should prosthodontics be a treatment option for tmd or bruxism ?

59. Correcting dental occlusion and/or repositioning the mandible for TMD treatment purposes is not medically necessary Given these premises, the general practitioner may be perplexed by the apparent occlusion-related effects of oral appliances (OA) on TMD symptoms.49,50 Oral appliances may favor reorganization of muscle fiber recruitment patterns51,52 and a shift in the area of highest joint loading. TRANSIENT EFFECTS OF OA ransient shifts in joint and muscle loading. Mandibular advancement devices are a option for OSA treatment, may actually reduce SB as a “side-effect” of OSA decrease induced by jaw advancement Daniele Manfredini, Carlo E. Poggio, Prosthodontic planning in patients with temporomandibular disorders and/or bruxism : A systematic review Journal of Prosthetic Dentistry 2016

60. Can prosthodontics cause tmds and/or bruxism ?

61. The biological plausibility that a centrally mediated phenomenon such as bruxism may be induced by a prosthetic treatment is nonexistant . The masticatory system has extraordinary powers of adaptation, both to natural dental-skeletal abnormalities and to iatrogenic modifications. However it has been stated that extensive rehabilitation which includes Increases in the occlusal vertical dimension (OVD) and mandible repositioning treatments might hold a possibility of being a risk factor. Daniele Manfredini, Carlo E. Poggio, Prosthodontic planning in patients with temporomandibular disorders and/or bruxism : A systematic review Journal of Prosthetic Dentistry 2016

62. For this reason, the safest prosthodontic strategy against the possible onset of TMD symptoms is not to plan occlusal modifications that jeopardize the capacity for accommodation. Rehabilitations based on preconceived ideal occlusal schemes or interarch relations are not advisable , as they fail to account for the muscle engrams and the functional adaptation that the neuromuscular system of an asymptomatic patient has developed naturally

63. For decades centric relation has been a controversial and much debated concept. Its definition evolved from a mechanically determined to a physiologically acceptable position This is also due to the absence of an ideal condylar position associated with a healthy TMJ or jaw musclefunction . Based on the wide range of physiologically acceptable centric relation and OVD values at the inter- and intraindividual level , the habitual position of the interarch relationship should be used as a reference. Whenever possible, and prosthetic treatments required to change it should provide the minimum shift from that position .

64. As a general rule, changes must be carried out only for valid prosthetic reasons and be performed over the longest possible period by testing adaptation with interim restorations .

65. How should prosthodontics (for prosthetic reasons)be performed in patients with tmds and/or bruxism ?

66. The patients with ongoing TMDs, their symptoms should be treated before starting any prosthetic treatment. The absolute contraindications- presence of TMJ and/or masticatory muscle pain Muscle soreness ( temporalis / masseter ) a limited range of joint movement Daniele Manfredini, Carlo E. Poggio, Prosthodontic planning in patients with temporomandibular disorders and/or bruxism : A systematic review Journal of Prosthetic Dentistry 2016

67. In addition, a certain freedom of movement is useful around the occlusal contact areas in maximum intercuspation to create flatter cuspal planes to protect the prosthesis during eccentric movements. As for the restorative material, research does not support any clinical evidence. The long-debated dispute on this topic ( high strength anatomic contour ceramics versus potentially chippable ceramics versus in-mouth restorable composite resins) has not yet been solved, and the choice of material for an extensive rehabilitation in patients with bruxism is often based on the clinician’s predilections and patient expectations. In that respect, restorations with occlusal devices worn at night should be protected.

68. Conclusion Bruxism is a common parafunctional habit, occurring both during sleep and wakefulness. As the etiology is multifactorial , there is no known treatment to stop bruxism , including prosthetic treatment. The management of bruxism should focus to prevent progression of dental wear, reduce teeth grinding sounds, and improve muscle discomfort and mandibular dysfunction in the most severe cases

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