Practical Approach to Splint Therapy

ABSTRACT

An occlusal splint has multiple functions and can be used for various therapeutic causes. It has many advantages and limitations as well. An oral appliance is dependent largely on the diagnosis and therefore, a thorough examination and history taking is necessary. Three cases of oral appliances have been discussed here to elucidate this.

INTRODUCTION

An occlusal appliance (splint) is a removable device usually made of hard acrylic, that fits over the occlusal and incisal surfaces of the teeth in one arch creating precise occlusal contacts with the teeth of opposing arch. Splint therapy may be defined as “the art and science of establishing neuromuscular harmony in the masticatory system and creating a mechanical disadvantage for parafunctional forces with removable appliances.”1Occlusal splint is a diagnostic, relaxing, repositioning, and reversible device. According to the glossary of prosthodontic terms 8th ed., “occlusal splint is defined as any removable artificial occlusal surface used for diagnosis or therapy affecting the relationship of the mandible to the maxilla. It may be used for occlusal stabilization, for treatment of temporomandibular disorders, or to prevent wear of the dentition.”1 A common goal of occlusal splint treatment is to protect the TMJ discs from dysfunctional forces that may lead to perforations or permanent displacements. Other goals of treatment are to improve jaw-muscle function and to relieve associated pain by creating a stable balanced occlusion. 2Two main types of splinting are available: Occluding and non-occluding. Occluding splints, also called stabilization splints, are specially fabricated to improve the alignment of the upper and lower teeth.

Non-occluding splints, also called simple splints, primarily open the jaw, release muscle tension, and prevent teeth clenching. Non-occluding splints are typically made of a soft-vinyl. 3

RATIONALE OF USING A SPLINT

FUNCTIONS OF A SPLINT

TYPES OF SPLINTS

According to Okeson:4

1.Muscle relaxation appliance/ stabilization appliance used to reduce muscle activity
2.Anterior repositioning appliances/ orthopedic repositioning appliance

Other Types

• Anterior bite plane
• Posterior bite plane
• Pivoting appliancee
• Soft/resilient appliance

According to Dawson

• Permissive splints/muscle deprogrammer
• Directive splints/non-permissive splints
• pseudo permissive splints (e.g Soft splints, Hydrostatic splint)

Full coverage/Partial coverage splints

ORAL APPLIANCE DESIGNS AND RELATED CONCEPTS

The type of splint is dependent on the diagnosis.A careful medical/dental history along with comprehensive examination is necessary for all patients

CASE REPORT 1

A patient, female, aged 36 yrs, reported to the department of prosthodontics with pain on the left side of her face. She gave history of joint sounds on opening the jaw on the left side since 4 months, which gradually ceased one month ago but also resulted in reduced mouth opening. Medical and dental history was taken andclinical examination was carried out. The examination of r/l side TMJ showed no pain, swelling or clicking. On palpation, extraorally, the region of the TMJ was non tender and no pain elicited from muscles of mastication. Intraorally, all teeth were present. The third molar in the third quadrant showed moderate decay, however on probing was limited to dentine and elicited no tenderness on percussion. There was no deviation or deflection but the mouth opening was painful and limited to two fingers wide (20mm). On inspection, a slightly hard end feel was sensed on the left side. Radiographic examination showed no abnormalities in the region of the condyle.(Fig 1) A differential diagnosis of disc displacement without reduction was drawn.
Initially, diagnostic impressions were made, Facebow transfer done and a centric bite registration taken. The casts were mounted on a semi adjustable articulator and a centric stabilization splint was fabricated from heat cure acrylic. This splint was inserted and the patient was instructed to use throughout the day except at meal times and recalled within 3 days.
Within this time period, patient reported with a surge in the level of pain on the left side TMJ region. On examination, there was no pain or tenderness in the muscles of mastication, no deviation or deflection. However, pain on opening the mouth persisted with reduced opening of 20 mm and pain on biting on the contralateral region.(Fig 2 and 3)The centric stabilizing splint was converted into an anterior repositioning splint by recording the intercuspation at a more comfortable forward position of the mandibular jaw by using self-cure acrylic in a chairside procedure. (Fig 4 and 5)The patient was advised to use the anterior repositioning splint along with moist heat fermentation application on the left side of the face near the TMJ.
Patient was recalled after 7 days, and although pain still persisted on the left side, it had reduced marginally and the mouth opening had increased to 28 mm. Patient still refrained from chewing on the contralateral side due to pain and eccentric protrusive and lateral movements also generated pain beyond 3mm. Patient was advised to continue use of the anterior repositioning splint along with moist heat fermentation on the left side.
Following this, a fortnightly appraisal was done of the patient. The mouth opening gradually increased from 28mm to 30mm, 35mm and 36mm in subsequent appointments with progressive relief. There was no deviation or deflection while opening and pain persisted only at maximal opening of the jaws. The mastication on the ipsilateral side was painless and eccentric movement was possible till 11mm. The contralateral side, however, elicited pain on mastication which gradually reduced and eccentric movement was possible till 9mm.
Once a mouth opening of 36mm was achieved in a matter of 6-8 weeks, the patient was slowly weaned off the anterior repositioning splint and instructed to use the splint 2 hours each morning and afternoon and then the entire duration of sleep. The patient was advised a regimen of relaxation and exercise therapy which has proven to be effective by few authors in studies.
Patient was coached to follow a pattern of stretching and strengthening the muscles of jaw closure and opening. It consisted of deep breathing exercises and application of moist heat fermentation along with the massage of the region of problematic condyle. Then gentle isometric tension exercises against resistance was advised followed by guided opening and closing and stretching exercises of the muscles of mastication. Patient was motivated and educated on the importance of following these exercises as a daily routine for improvement of the ailment.
After an observatory period of another fortnight, patient was recalled and reviewed. The mouth opening measured 38mm without pain. The eccentric protrusion and laterotrusion had become fairly less painful with a movement of 11mm on the ipsilateral and 10mm on the contralateral side.(Fig 6) Patient had followed the instructions, claiming initial difficulty which later improved upon daily routine. She was then counselled to limit the splint to nightly use only, follow a soft diet and to keep the routine jaw exercises.
After an interlude of 2 weeks, the patient was recalled and assessed. The overall condition on the left side TMJ had improved with nearly normal mouth opening, eccentric movements and masticatory capacity within reasonable limits. The anterior repositioning splint was converted into a centric stabilizing splint and the patient was directed to use it for 20 days more and then discontinue afterwards. The jaw exercises were to be continued for another month.

Although, it’s not clearly discernable if the displaced disc was recaptured, in most cases, it is sufficient to strengthen the retrodiscal tissues on which the condyle rest and train the joint for movements in its new position.

CASE REPORT 2

A 28 yr old female patient reported with neck pain on the left side since 5-6 months. On palpation, tenderness present with respect to the left masseter, medial pterygoid, temporalis and sternocleidomastoid. There was pain in the region of the TMJ and general increase in temperature on the left side of the face with slight puffy appearance. (fig 7) Intraorally, all teeth were present. There was restricted mouth opening of 23mm with slight deviation towards the left.(Fig 8)Radiographic examination revealed normal morphology of coronoid and condyloid processes. A differential diagnosis of local myositis was drawn.
The patient was prescribed moist heat treatment 3 times a day with ice pack application once a day in the evening for duration of one week.
After a week, the patient had improved considerably with reduced pain and swelling on the left side of her face, improved mouth opening measuring 28mm and overall relief. She was instructed to continue therapy for another week.
At the following appointment, impressions of the maxillary and mandibular arches were made, Facebow transfer done and a centric bite registration was recorded after deprogramming the muscles with a lucia jig.(Fig 9) These records were used to mount the casts on a semi adjustable articulator and fabricate a centric stabilizing splint of heat cure acrylic resin with canine guided disclusion.(Fig 10) The fit and insertion of the prosthesis was done. She was advised to continue moist heat treatment and recalled after a fortnight.
After the interlude, patient reported with diminished pain in the left side of her face and improved mouth opening than the first visit but the symptoms hadn’t completely ceased. Hence, the patient was counselled on stress management and its resultant effects on the muscles of mastication and advised to practice deep breathing, meditation or yoga in conjunction with the splint and moist heat therapy.
In subsequent reviews, patient reported a remarkable relief from the onset. The successful outcome maybe in part due to the splint therapy and the realisation of the stress induced condition. Nevertheless, local myositis has a multifactorial origin and a treatment based trial and error to provide palliative relief along with encouragement to tackle personal stress has brought respite in this patient’s situation.

CASE 3

A male patient, age 42yrs, reported to the department of prosthodontics, complaining of generalised sensitivity of his teeth. Patient had no significant medical and dental history and extra oral examination revealed no significant findings. Intra oral examination disclosed generalised attrition and abrasion of all his teeth and the OPG revealed generalised loss of enamel over the occlusal surfaces of all teeth. (Fig 11,12)
The patient was asked to describe his lifestyle, eating habits, hobbies, routine and work environment. The patient divulged that he has episodes of depression at his work place and experiences isolation even in a crowd. He informed that he practices yoga and meditation to overcome the same. His family had complained about the grinding noises while he is asleep and under duress the patient recalls subconsciously clenching his teeth. Patient consumes a mixed diet. He also admitted to brushing his teeth with an unspecified ayurvedic powder.
From the totality of his history, a differential of sleep bruxism and daytime clenching was diagnosed.
Impressions of the maxillary and mandibular arches were made, Facebow transfer done and a centric bite registration was recorded after deprogramming the muscles with a lucia jig. These records were used to mount the casts on a semi adjustable articulator and fabricate a centric stabilizing splint of heat cure acrylic resin with canine guided disclusion. The fit and insertion of the prosthesis was done.(Fig 13)
The patient was educated on the detrimental effects of large particle tooth abrasives such as tooth powders. He was advised to wear the occlusal splint/ nightguard during sleep time. During the day he was trained to continuously blow air and maintain no contact between teeth while not in speech, mastication or swallowing.
Bruxism is a cognitive disorder that requires conscious direction of the patient away from clenching and grinding of his teeth. While the occlusal splint does not cure bruxism, it helps to protect the teeth from the harmful forces exerted subconsciously at night.

DISCUSSION

Dental occlusal splinting and permanent occlusal adjustment have been the mainstays of TMJ disorder treatment.5Many therapies have been advocated for treating TMD. A therapy that is commonly provided is an occlusal orthotic, also called a dental or occlusal appliance or a splint.The appliance can be made to cover the occlusal surfaces of maxillary or mandibular teeth and can be fabricated from many different materials, giving it a hard, soft, or intermediate feel. Occlusal orthotics is beneficial for masticatory muscle pain, TMJ pain, TMJ noises, restricted jaw mobility, and TMJ dislocation.6
Splint therapy is considered an adjunct to pharmacologic therapy and most appropriate when nocturnal parafunctional activities can be identified. Typically, a flat-plane maxillary occlusal splint designed for bilateral contact of all teeth is fabricated. Such splints are thought to unload the joint by disarticulating the dentition and increasing the vertical dimension of occlusion. By unloading the joint, there will be a reduction in both synovitis and masticatory muscle activity. Therefore, the result is a reduction in symptoms. These appliances may also change condylar position and the existing occlusal relationship, thereby reducing abnormal muscle activity and spasm.7
In these above discussed cases, relief from symptoms was achieved over a long treatment period. The pain reduced and mouth opening improved and good tolerance was achieved. The credit for this in major part lies with the patient’s self motivation to follow the instructions and exercises without falling through.

CONCLUSION

Over the past 10-20 years, the conceptual basis for using oral appliance in treating TMDs and bruxism has been dramatically redefined.Currently, OAs are still regarded as useful adjuncts for treating certain kinds of TMD patients but the emphasis is entirely on their conservative application.Evidence suggests that OAs are more effective in treating myogenous problems than intracapsular conditions but can be helpful for both in properly selected cases.
There is sufficient credible literature to support the use of splint therapy to reinstitute neuromuscular harmony in the compromised masticatory system.Dental practitioners have a responsibility to understand and provide this treatment, monitor the condition, and refer the patient to another specialist in the concerned field if necessary.

Splint therapy helped in the overall well being of the patient, reduction of symptoms and comfort of the patient through symptomatic relief.

REFERENCES