The Clinical Features And MRI Manifestations Of Oral Maxillofacial In Myotonic Dystrophy Patients

Objective: The purpose of this study was to evaluate oral health status and the masticatory muscles(masseter,medial pterygoid and lateral pterygoid)involvement through clinical,X-ray and MRI in DM1 patients and research the relationship between abnormality of masticatory muscles and the change of occlusion,face type,mouth opening and the bite force and explore the effective methods to treat the malocclusion and improve the patients' oral health.Methods:1 Subjects and groups10 patients who were diagnosed with dystrophia myotonic 1 from October 2014 to December 2015 in the department of neuromuscular disease of the Third Hospital of HeBei Medical University were selected as the study group,all patients had genetic analysis and skeletal muscle biopsy,the patients had signed the informed consent.The inclusion criteria: 1)The distal muscle group of limbs appeared myotonia,muscle weakness or muscle atrophy;had a face liked axe;the CK of serum was normal or mildly increasing;the EMG of muscle showed typical myotonia potential which with or without myopathy potential;2)The pathology of the biopsy skeletal muscle showed typical center nucleus,nucleus aggregation and sarcoplasm block;muscle fibers had different size,I type of muscle fibers occured atrophy,? type of muscle fibers was dominant;3)Gene analysis: had clearly confirmed mutations which was the length of a CTG trinucleotide repetition in the 3' untranslated region of the DMPK gene located on chromosome 19q13.3 by improved PCR high GC content segment detection.20 adult volunteers who were randomly chosen in people for oral health physical examination from October 2014 to December 2015 in the department of oral medicine of the Second Hospital of HeBei Medical University as the control group.All the selected subjects had no history of major diseases.2 Summary analysis1)Summarized and analyzed clinical data of DM1 patients,which included the name,the age,the gender,family history,the onset form of disease,limb skeletal muscle involvement,genetic testing results,CK,EMG,food preference(pancake,rice or noodle)and mouth breathing;2)Checked all the subjects oral status which included DMF index(DMFT),simplified calculus index(CI-S),occlusion and maximum opening degree;3)Measured the palatal arch width and the maximum palatal arch height through making oral teeth print mode and measured the mandibular plane angle(MP-FH)through shooting x-ray lateral radiographic films;4)Measured and recorded the maximum bite force of the subjects using the bite dynamometer;5)According to the degree of muscle involvement and fat,assessed masseter,lateral pterygoid and medial pterygoid through shooting maxillofacial MRI.3 Statistical analysisAll dates were statistically analyzed utilizing SPSS16.0 software by two independent sample t test.All the data were expressed as mean ±standard deviation.Inspection level was set to?= 0.05.A probability value of P < 0.05 was considered statistically significant.Results: 1 The analysis of patient's general conditionThe study group includeded man and woman;the main initial symptoms of disease in patients was myotonia(50%),next muscle weakness(30%),for other reasons(20%);patients who liked to eat soft food was 8 cases(80%);the habit of mouth breathing when sleeping at night was 6 cases(60%).2 The statistical analysis of oral health status The DMFT of study group and control group was respectively 4.30 ± 2.41 and 1.45 ± 1.28,the CI – S of two groups was respectively 7.30±3.06 and 1.70±1.34;there was a significant difference between two groups and the difference was statistically significant(P < 0.05).The DMFT and CI-S of study group was larger than the control group.3 The contrastive analysis of the face type and facial features 3.1 The analysis of the occlusionThere were six cases manifestated Class III,including of anterior teeth open in 4 cases.There were four cases with Class I,including of anterior teeth open in 2 cases.3.2 The statistical analysis of the mandibular plane angle(MP-FH)The MP-FH of study group and control group was respectively 31.73 ±2.08°and 27.89 ±1.81°;there was a significant difference between two groups and the difference was statistically significant(P < 0.05).The MP-FH of study group was larger than the control group.3.3 The statistical analysis of the maximum opening degreeThe maximum opening degree of study group and control group was respectively 3.51±0.22 cm and 4.59±0.32cm;there was a significant difference between two groups and the difference was statistically significant(P < 0.05).The maximum opening degree of study group was smaller than the control group.3.4 The statistical analysis of palatal width and maximum palatal heightThe palatal width of male in study group and control group was respectively 33.88 ±1.31 mm and 39.01±2.45mm;the palatal width of female in two groups was respectively 33.93±1.55 mm and 36.86 ±1.21 mm,there was a significant difference between two groups whether male or female and the difference was statistically significant(P < 0.05).The palatal width of study group was smaller than the control group whether male or female.The maximum palatal height of male in study group and control group was respectively 20.20±1.04 mm and 16.44 ± 0.54mm;the maximum palatal height of female in two groups was respectively 18.93 ±0.80 mm and 15.34 ± 0.48mm;there was a significant difference between two groups whether male or female and the difference was statistically significant(P < 0.05).The maximum palatal height of study group was bigger than the control group whether male or female.4 The statistical analysis of the maximum bite forceThe maximum bite force of male in study group and control group was respectively 422.70±63.41 N and 550.29± 27.62 N;the maximum bite force of female in two groups was respectively 365.22±34.42 N and 454.85± 20.87N;there was a significant difference between two groups whether male or female and the difference was statistically significant(P < 0.05);there was a no significant difference between male and female in study group and the difference was no statistically significant(P >0.05).The maximum bite force of study group was smaller than the control group whether male or female.5 The image acquisition and analysis of masticatory muscle MRI 10 cases of patients were shooted maxillofacial MRI,we chosen the transaction images to analyze masseter,lateral pterygoid and medial pterygoid.The high signal change in T1-WI and T2-WI occurred in 9 patients' masseter,8 patients' lateral pterygoid and 7 patients' medial pterygoid.The involvement was similar on both sides in all cases.Affected muscles presented areas of increased signal with loss of the characteristic homogeneous pattern and loss of contrast between the muscle contour and adjacent fat.In the mostly affected muscles,increased signal was diffuse and similar to the signal of the subcutaneous fatty tissue.Inflammation or edema-like changes were not observed in the masticatory muscles of these patients with fat suppression techniques.The degree of fatty infiltration concentrated in grade 1,2,3.The abnormal signal was not found in masseter,lateral pterygoid and medial pterygoid in control group.Conclusions:1 During the period of young adults DM1 patients had malocclusion predominantly in maxillofacial abnormal which affected normal chewing and swallowing function,therefore we should suggest early intervention treatment.2 DM1 was ion channel diseases which was chloride channel abnormal,therefore drug therapy with sodium channel blockers(carbamazepine,mexiletine)before the oral and maxillofacial orthodontic treatment which can alleviate symptoms of systemic myotonia in order to improve the precision of orthodontic treatment.3 DM1 patients had skeletal muscle involvement and often accompanied by systemic diseases(such as diabetes)which increased adverse effects of oral health,we should pay attention to the early oral care for the patient.4 For the orthodontics patients with malocclusion and specific features,we should conduct maxillofacial MRI positively.When we found masticatory muscle with suspicious lesions,we should consider whether had the possibility of systemic disease of the skeletal muscle and suggest further diagnosis for patients in case of missed diagnosis.