Evaluation of Masticatory Muscle Activity in Patients With Unilateral Posterior Crossbite Before and After Rapid Maxillary Expansion
试验速览
- 阶段
- 不适用
- 入组人数
- 100
- 试验地点
- 2
- 主要终点
- Symmetrical mastication index
研究概览
简要总结
Posterior crossbite (PCB) is defined as the presence of one or more teeth of the posterior group (canine to third molar) in an inverted buccolingual relationship, where the vestibular cusp of the upper tooth is in contact with the central fossa of its lower antagonist tooth. It is one of the most common malocclusions in children, with a prevalence of 8 to 22% among orthodontic patients in primary and mixed dentition and 5 to 15% among the general population. It can be bilateral (MCPB) or unilateral (MCPU). In 71-84% of cases, CCM in growing patients appears as a functional CCBM and is therefore associated with a functional mandibular deviation.
The hypothesis of this study is, that unilateral posterior crossbite correction by Rapid Maxillary expansion achieves improved symmetry and muscle activation potential in treated patients.
The objective of this study is to evaluate the muscle activity of masticatory muscles in patients with unilateral posterior crossbite with superficial electromyography before and after treatment with rapid maxillary expansion.
Superficial electromyography will be measured in masseter and temporalis muscle before treatment, when the patients bite is corrected and after the treatment.
Three static and two dynamic tasks will be measured.
详细描述
Posterior crossbite (PCB) is defined as the presence of one or more teeth of the posterior group (canine to third molar) in an inverted buccolingual relationship, where the vestibular cusp of the upper tooth is in contact with the central fossa of its lower antagonist tooth. It is one of the most common malocclusions in children, with a prevalence of 8 to 22% among orthodontic patients in primary and mixed dentition and 5 to 15% among the general population. It can be bilateral (MCPB) or unilateral (MCPU). In 71-84% of cases, CCM in growing patients appears as a functional CCBM, and is therefore associated with a functional mandibular deviation.
There is evidence that an altered relationship between upper and lower teeth is associated with differences in the temporomandibular condyle-temporomandibular fossa relationship between the right and left sides. Asymmetric masticatory function in patients with CCM has been related to differences in development between the right and left sides of the mandibular bone during growth, asymmetric contraction of the masticatory musculature, decreased thickness of the cross-sided masseter muscle and altered masticatory pattern. Therefore, previous studies suggest that UCPM may contribute to the development of skeletal asymmetries and temporomandibular disorders (TMD). Given that the most frequent cause of UCPD is the reduction in maxillary width, other authors conclude that early treatment with Rapid Maxillary Expansion (RME) would be recommended to reduce the risk of developing TMD and craniofacial anomalies in adulthood, due to postural alterations and asymmetric function and growth of skeletal and muscular structures.
Muscle activity is commonly recorded in research using surface electromyography (sEMG). sEMG has previously been used in similar studies because it is less invasive than intramuscular electromyography. However, sEMG data can be affected by various artifacts, resulting in questionable interpretation of the results. For this reason, Ferrario et al. described a method to standardize myoelectric potentials, with indices that record the activation of the levator muscles and the level of symmetry in activation between contralateral muscle pairs. This protocol reduces within-sample variability and can be used for the assessment of masticatory muscle activity during static and dynamic tasks.
The hypotheses of this study are:
Patients with unilateral posterior crossbite have less activity of masseter and anterior temporalis muscles during masticatory function than patients with normal occlusion.
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Single (Outcomes Assessor)
入排标准
- 年龄范围
- 9 Years 至 15 Years（Child）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Mixed or early permanent dentition.
- •Complete eruption of the first four permanent molars.
- •Angle Class I ±1 mm.
排除标准
- •Systemic diseases or congenital anomalies affecting craniofacial growth or development.
- •Signs or symptoms of temporomandibular disorder (TMD).
- •Dental pain.
- •Previous orthodontic treatment.
结局指标
主要结局
Symmetrical mastication index
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
assess whether the left and the right side chewing tests were performed with symmetrical muscular patterns. It indicates the distance between the centre of the chart and the centre of the ellipse in a graph that describes the prevalence of one side over the other during mastication. SMI ranges between 0 per cent (no symmetry) and 100 per cent (symmetrical muscular pattern). Normal values are 70 per cent ≤ SMI ≤ 100 per cent.
torque coefficient
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
This index is obtained by measuring the overlapping activity (standardized EMG waves) between the left MM and right AT and the right MM and left AT. The higher muscular activity of one couple (i.e. left MM and right AT) over the other (i.e. right MM and left AT) results in a torquing effect on the lower jaw. TC ranges between 0 per cent (no symmetric activation of the couples, greatest torquing effect) and 100 per cent (perfect symmetric activation of the couples, no torquing effect). Normal values are 90 per cent ≤ TC ≤ 100 per cent.
percentage of overlapping coefficient (%)
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
The standardized EMG waves of the left and right anterior temporalis (AT) and masseters (MM) were compared by computing a percentage overlapping coefficient (POC, unit: %, range: 0-100 per cent, norm values 85 per cent ≤ POC ≤ 100 per cent). If the muscles contract with perfect symmetry, a POC of 100 per cent (perfect symmetry) is expected. Conversely, a value corresponding to 0 per cent indicates the absence of concurrent activation of paired muscles (no symmetry). Three indices were computed for each subject (POC AT, POC MM and POC medium).
Muscle activity (microVolts)
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
sEMG is a NON-invasive method that measures the electrical activity of the muscle generated by the passage of the nerve impulse, which causes depolarization of the muscle cell membrane during excitation. Once the muscle is contracted and receives electrical signals, the electrodes pick up these signals and record them on the device application.
Asymmetry index
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
This index is calculated by comparing the activity of the right couple (right AT and right MM) to the left couple (left AT and left MM). ASIM ranges from -100 per cent and +100 per cent; a value of 0 per cent depicts a perfect symmetric activation of the two couples. A negative value indicates greater activity of the left couple; conversely, a positive value indicates a greater activity of the right couple. Norm values are -10 per cent ≤ ASIM ≤ +10 per cent.
side of prevalent mastication
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
in case of SMI values lower than 70 per cent, the dominant side of mastication was identified as side of prevalent mastication. Three categories could be identified, that is right, left and symmetric.
Total standardized muscle activity
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
This index is computed as the integrated area of the EMG standardized potentials of both MM and AT over time (5 seconds MVC). Norm values are 85 per cent ≤ IC ≤ 115 per cent. Lower values indicate that the EMG standardized potentials were reduced during the clenching tasks, and that the maximal EMG activity could not be expressed
frequency index
时间窗: change between baseline and 1 week follow-up; change between baseline and 6 months follow-up.
measures the frequency of masticatory cycles during the chewing experimental tasks and was reported in hertz (Hz: bites per second)
次要结局
未报告次要终点
研究者
Albert Pérez Bellmunt
Principal Investigator
Universitat Internacional de Catalunya