Gnathological splint therapy in temporomandibular joint disorder.

Temporomandibular joint (TMJ) forms an integral functional part of stomatognathic system. Position, shape, structure and function of teeth have an influence on the proper functioning and health of TMJ. But a problem associated with TMJ is often neglected, and treatment for it is mostly restricted to palliative therapy. A proper understanding of the underlying cause of temporomandibular joint disorder (TMD) is necessary to device a proper treatment plan. Etiology of TMDs varies from idiopathic reasons to systemic disorders. The option of Gnathological splint is a conservative, safe and an effective mode of therapy for TMDs caused by occlusal discrepancies (fulcrum/interferences). This article presents a case report of a patient with TMD caused by occlusal discrepancy.

Temporomandibular joint (TMJ) disorders refer to a poorly understood set of complex conditions, manifested by pain in the areas of the jaw and associated muscles and limitations in the ability to make the normal functions like phonation, facial expression, mastication and deglutition. Etiology of temporomandibular joint disorders (TMDs) varies from idiopathic reason to systemic disorders.[1] Treatment for TMD's varies widely depending on their etiology. The option of gnathological splint is a conservative, safe and an effective mode of therapy for TMDs caused by occlusal discrepancies (fulcrum/interferences).[23] This article presents a case report of a patient with TMD caused by occlusal discrepancy.

Case Report

A 27-year-old male patient reported to the department of orthodontics with a chief complaint of pain in the jaw joint region on both sides for the past 3 months. Patient also revealed frequent episodes of headache and neck stiffness [Figure 1a–c].

Figure 1(a-c)

Extra oral photographs

Examination

On examination, it was noted that the patient had bilateral initial opening clicks, deviation of the mandible toward right on opening and tenderness on palpation of masticatory muscles.

Joint mapping (Rocabado) indicated bilateral inflammation of the retrodiscal tissues (tenderness on palpation of the posterior joint space).[4]

On the manipulation to centric relation (CR), the interference/Fulcrum was spotted on the maxillary left 2nd molar region.[5] To avoid this interference the patient habitually shifts the mandible to the right, distracting the condyles leading to a sequence of events [Chart 1], resulting in TMD.[6]

Chart 1

Pathophysiology of temporomandibular joint disorders due to occlusal discrepancies

Radiological interpretation

Cone-beam computed tomography (CBCT)-at the mid condylar section [Figure 2] – it was observed that there was an increase in joint space in the superior aspect indicating a downward displacement of the condyle from its optimal position.[7]

Figure 2

Cone-beam computed tomography Image-pre splint therapy

Measures condylar distance interpretation

Downward displacement of the condyle by 2.9 mm [Figure 3].

Figure 3

Measures condyle displacement (MCD) Interpretation before splint therapy (a) transverse recording (b) left condyle (c) right condyle

Diagnosis

Bilateral downward distraction of condyles with associated anterior disc displacement with reduction.

Treatment plan

Gnathological splint therapy for 6–8 months.[8]

Fabrication of Gnathological Splint

Maxillary and mandibular impressions were taken using an irreversible hydrocolloid in sterilized metal rim-lock trays. All impressions were disinfected for 5 min with ioda-5, then rinsed with water and sprayed with a debubblizing surfactant before being poured with Type 4 Gypsum.

Face-bow transfer records were taken using the AD2 face-bow Advanved Dental Designs, USA. It records the relationship of the maxilla to the cranium [Figure 4a and b].[9]

Figure 4

Face bow transfer (a) frontal view (b) profile view

Centric relation bite

Centric relation bite (Roth power centric) [Figure 5] was taken with Delar bite registration wax in two sections, one in the anterior region and the other in the posterior region.[1011] The patient was seated in the dental chair reclined at an angle of 45° to the floor. To take the anterior section, the wax (2–3 layer thickness) was cut in a shape and appropriate size to register from canine to canine. The wax was then heated until soft in a water bath at 138°F. The wax bite was then placed in the patient's mouth extending from canine to canine. The patient's mandible was then manipulated (to CR) to make an interocclusal registration in the anterior section. The patient was then instructed to close until the posterior teeth were discluded approximately 2 mm in the area of the second molars. While in the closed position, an air syringe was used to begin the cooling process. The anterior record was then removed, and stored in chilled water.

Figure 5

Roth power centric bite

The posterior section was trimmed wide enough to include the first molar and second bicuspid teeth extended across the arch. The wax was then softened and placed on the maxillary posterior teeth. With the posterior section in place, the chilled anterior portion was placed back in position again. The patient was then guided in the same manner to close into the hardened anterior segment and asked to bite as firmly as possible and hold it. This allowed the patient's musculature to aid in seating the condyle in CR position. Both the bites were then removed and stored in chilled water.

Mounting

With the help of face-bow transfer record, the maxillary model is mounted to the articulator with the mounting plate and mounting plaster [Figure 6]. Sufficient time is allowed for the plaster to set. The incisal guide pin is raised by 3 mm. To mount the lower model, the articulator is inverted, the centric wax bites are placed on the maxillary model, and the mandibular model is placed into the wax. A mounting plate is fastened to the lower member of the articulator, and the mandibular model is mounted, using mounting plaster or dental stone.

Figure 6

Mounted models

Splint fabrication and trimming

Splint was fabricated with cold cure acrylic resin at a position with 3 mm clearance from the fulcrum. The splint was then allowed to set for sufficient time. With the splint still not removed from the articulator, initial trimming was done to establish centric stops and mutually protected functional occlusal pattern. The splint later was adjusted in the patient's mouth to do further trimming to establish the same [Figure 7]. The patient was advised to wear the splint full time.

Figure 7

Splint with centric stops

Patient was recalled every month, and the splint was checked for centric stops and mutually protected occlusal pattern each time.[12] The mandible was checked and guided to centric, and it was noted that each time, the mandible exhibited lesser resistance indicating the reduction in muscle stiffness due to deprogramming.[13]

Postsplint observations

At the end of 8 months of splint therapy, the patient reported with a:

A drastic reduction of pain in the TMJ region

Reduction in the frequency and severity of headache.[1415]

On examination after 8 months of splint therapy

Bilateral clicks were not seen

No tenderness or pain in the region of muscles of mastication

No deviation in mouth opening

Most importantly, patient had the occlusal contact only in the fulcrum/interference point [Figure 8].

Figure 8

(a) Pre-treatment (b) Post-treatment (8 months)

Postsplint cone-beam computed tomography findings

Indicated the correction of condylar Distraction as the position, and joint space were found normal [Figure 9].[7]

Figure 9

CBCT Image – post splint therapy

Postsplint measures condylar distance findings

Mandibular position indicator reading showed change in condylar position in support of the CBCT findings.

Discussion

The etiology of TMDs can be unifactorial or multifactorial, and the treatment for it depends on the etiological factor (s). One of the most common causes of TMDs is occlusal discrepancies, and this is one area where the treatment option has been tried and tested to success to some extent. The patient had TMD due to a fulcrum in the maxillary left second molar region. The proprioceptive sense of the patient detects this interference as inconvenience and forced the patient to search for a more convenient position with maximum occlusal contacts in spite of one. In doing so, the patient automatically distracted the condyle to a musculoskeletally unstable position.[1617] At this habitual occlusal position, the patient is able to make more occlusal contacts but at the cost of the health of the TMJ and muscles of mastication. If left unattended the patient ends up in TMD with derangement of condyle disc assembly.[18] The gnathological splint was given to the patient to deprogram the muscles from this distracted position and to move the condyle to a more optimal and stable position. After 8 months of splint therapy, the patient exhibited lack of symptoms and the records taken at this time indicated the correction of condylar position.

Now the challenge lies in establishing a proper occlusion by orthodontic treatment in accordance with the optimal condylar position achieved by splint therapy.[19] A proper orthodontic diagnosis should be made at this stage when the condyles are seated in centric. In other words, the objective should be to establish centric occlusion (CO) in CR position (CR = CO).[20]

Conclusion

Temporomandibular joint forms an integral functional part of stomatognathic system. Position, shape, structure and function of teeth have an influence on the proper functioning and health of TMJ. It becomes important thus when the position and occlusion are changed for treatment, it is imperative to check for joint's health and joint position and even more important to establish the occlusion in optimal condylar position. As evident from this case, the orthodontic diagnosis and treatment planning has changed drastically when the condyles are positioned in CR position. Diagnosis and treatment planning done at this optimal position helps in achieving proper orthodontic treatment results, which will remain stable and in harmony with healthy TMJ.