Influence On Condyle And Joint Disc After RW-splint Treatment In Patients With TMD

Temporomandibular disorder (TMD) is a common condition and frequently encountered disease in oral system. Anterior disk displacement (ADD) is one of the common diseases in the temporomandibular disorders, including reusable disc displacement and anterior disk displacement without reduction.The current treatment of temporomandibular disorder are available,e.g:(occlusion therapy, physical therapy, arthroscopic treatment, drug blocking treatment.) The occlusion therapy as a conservative, reversible and the most commonly used treatment,it also can effectively improve the clinical symptoms.Magnetic resonance imaging (MRI) is a non-invasive, no radiation, high resolution in soft tissue examination methods, it can clearly demonstrated that joint,soft and hard tissue structure through its multi-sequence, multi-dimensional.In a word, MRI is one of the most effective means to diagnose patients with TMD joint disc displacement and deformation.This study compares the use of MRI imaging and RW-splint treatment of articular disc displacement before and after treatment in order to explore the influence of the internal structure of joints by RW-splint.Objective:To investigate the change of temporomandibular joint disc and condyle before and after RW-splint treatment in patients with ADD TMD, in order to explore the therapeutic mechanism and efficacy of RW-splint. It can provide a reasonable scientific basis to make the RW-splint better for the treatment of TMD clinically. Method:An object of study:This study collect20TMD patients that visit the Third Affiliated Hospital of Stomatology Hospital of Guangdong Province, Sun Yat-sen dental joint disc displacement, who have been treated by RW-splint, including7males and13females, at an age of13-30years, means16.8years old during2009-2012. Their treatment for6to21months(mean11.7months). Inclusion criteria:(1) comply with TMD research diagnostic criteria (RDC/TMD) Axis I:(2) MRI imaging confirmed bilateral joint front disc displacement Before the treatment;(3) have been treated by RW-splint therapy.(4) the information is complete before and after the treatment (such as MRI, CBCT, etc.) Exclusion criteria:the image data isfuzzy.(2) Condylar severely retarded.Research:In20patients, the temporomandibular area at both sides was scanned at closed position the maximum mouth open position through the1.5T superconducting MRI apparatus (General Electric Corporation, U.S.A.) to compare before and after treatment. Firstly,determine the oblique sagittal (perpendicular to the long axis of the condyle) and oblique coronal (parallel to the long axis of the condyle) scanning direction. In this direction, the line scanning proton density-weighted images, fast spin echo T1-and T2weighted image scanning. Imaging parameters: oblique sagittal slice thickness2mm, pulse repetition time200ms, echo time of24ms. Oblique coronal slice thickness2mm,pulse repetition time475ms, echo time of24ms.2.1articular disc-condylar angle measurement and analysisApply PACS image diagnostic workstation software for measuring and observing the following content.Condylar angle measurement-Drace conduct joint disc using standard plate boundaries that angle method. Plate boundary angle method:On oblique sagittal T1-weighted images, the joints between the panels and dual zone late with a clear dividing line (plate boundary), with after-hours joint condyle is located on top of the plate boundary12:00condylar position angle (angle plate boundaries) formed in the front and rear vertical10°, the relationship is defined as normal disc protrusion, disc forward over the boundary is defined as the angle of10°anterior disc displacement; backwards over plate angle of10°is defined as the boundaries of the joint after-hours shift. Also, by measuring the degree of severity of disc displacement judgments of the disease, with Ogutcen-Tollor M method use to change the position of the temporomandibular joint disc cases studied, the angle edge and after-hours between condylar center by measuring the vertical the anterior disc displacement divided into five levels. Normal0level which is0～10°,level Ⅰ is mild anterior disc displacement for11～30°, level Ⅱ is moderate level of31～50°, level Ⅲ is severe anterior disc displacement of51～80°, anterior disk displacement without reduction gradelVwas80°or more. This method is evaluated by using the RW-splint for patients to improve the anteroposterior relationship of disc condyle.2.2articular disc change positionUsing a coordinate measuring method in the articular disc change x, y-axis coordinate values before and after treatment were measured to assess the degree of articular disc displacement, position changes observed in patients with articular disc in the horizontal direction, vertical direction, to change its position analysis.2.3the change of condylar positionUsing a coordinate measuring method in the articular disc change x, y-axis coordinate values measured before and after treatment, observed in patients with articular disc position in the horizontal direction, vertical direction change, evaluate change its position.2.4the change of the length of the articular discRespectively, before the trailing edge of the articular disc with the leading and trailing make a tangent line, the horizontal distance between the two tangents which represents the length of the articular disc.2.5Analysis of morphological changes of the articular discNormal articular disc is in the sagittal, MRI showed a double-concave, is thicker front with thin intermediate zone and the thickest of the band on the image. MRI to determine the shape of the articular disc:According to skaya-Yil-maz and Ofutcen-Toller They classified the articular disc double into concave shape, both thick type, elongated, double convex, later with enlargement, round, folding type, in addition to double concave, the rest of the morphological changes of the articular disc defined articular disc deformation.Results:1.The analysis of the relationship between joint disc and condylar:Compared with pre-treatment, After RW-splint therapy①both sides of TMJ in the closed-mouth position, the angle of disk-condyle was reduced by RW-splint for20parents, decreased significantly (P<0.05)②The angle of disk-condyle was reduced after treatment after treatment in maximum opening-mouth position for20parents, but the difference was not statistically significant (P>0.05)。2.The Change of position of the articular disc:Compared with pre-treatment, After RW-splint therapy①The change of the coordinate values of articular disc in the closed-mouth position showed that:20parents’disk coordinate values of x were increased,decreased significantly (P<0.05).condyle coordinate values of y were reduced,the difference was not statistically significant(P>0.05).②The change of the coordinate values of articular disc in maximum opening-mouth position before and after RW-splint treatment showed that:the left of20parents’disk coordinate values of x were decreased,but increased of y,the difference was not statistically significant (P>0.05)。 Both of coordinate values of x and y of the right of articular disc were increased,which were not statistically significant (P>0.05).3.Changes in condylar position:①The coordinate values of condylar position in the closed-mouth position showed that:Compared with pre-treatment,Both sides of the condylar position of coordinate values of x and y were decreased in the20patients after therapy,decreased significantly (P<0.05).②The coordinate values of condylar position in maximum opening-mouth position showed that:the left sides of the condylar position of coordinate values of x and y were increased,which was not statistically significant (P>0.05).The right sides of the condylar position of coordinate values of x was increased,but the y was decreased,and those were not statistically significant (P>0.05). 4.The changing result of length of joint disc:Compared with pre-treatment,the length of joint disc of20parents in the closed-mouth position decreased from9.83±1.17mm to9.40±1.36mm at the left side, and decreased from10.22±1.26mmto9.23±1.46mm at the right side After the treatment,which was significantly (P<0.05).②In maximum opening-mouth position,the left length of joint disc increased from10.21±1.33mm to10.96±1.31mm, and the right side increased from10.68±1.33mm to11.33±1.54mm,so the difference before and after treatment were not statistically significant(P>0.05)。5.the change of articular disc shape:in20patients with anterior articular disc displacement, the change of articular disc shape after RW-splint treatment were not statistically significant (P>0.05)。Conclusions:1. RW-splint treatment can improve the relation of disc-condyle.2. RW-splint treatment can improve the position of joint disk,which can return backward relative to condyle. can improve the position of the condyle,make the displacement of condylar, moving forward,down to normal physical location.3. RW-splint treatment can make the shorten of joint plate of elongation, Reduce the intra-articular injuries of the organization.4. RW-splint treatment can make the shorten of joint plate of elongation, Reduce the intra-articular injuries of the organization.5. RW-splint is effective, safe, reversible, non invasive and can be used as one treatment for patients with ADD TMD.