Motor behavior of masticatory muscles in individuals with unilateral trans-incisive foramen cleft lip and palate*

Objective: To investigate whether children with complete unilateral cleft lip and palate (CLP) have altered control of masticatory muscles.

Methods: The muscular activity of 66 children with CLP (n = 33) and without CLP (n = 33), aged 6–12 years was assessed during different tasks (rest, isometry, mastication) using electromyography.

Results: The activation for the analyzed muscles was higher in children with CLP at rest (R) and inactive period (IP) (p < 0.05). The muscles of children with CLP remained active for longer than those without CLP (p < 0.05), and the length of the masticatory cycle was higher in children with CLP (p < 0.05).

Conclusion: Children with CLP have longer muscle activation and increased cycle time during the chewing cycle, which might be a consequence of malocclusion, resulting in difficulty chewing.     

Temporomandibular disorder treatment in a patient wearing removable prostheses: A case report

Aim: The purpose of this intervention was to treat the patient, a 51-year-old woman, who was wearing a maxillary denture and a mandibular bilateral distal-extension partial denture (both unfit) and was suffering from temporomandibular disorder (TMD).

Methodology: The treatment suggested was to construct a superior repositioning splint (SRS), and after remission of the symptomatology, fabricate new dentures.

Results: The occlusal splint was effective and the symptomatology ceased after about five months of treatment. The new dental prostheses were made and followed up for 10 years with no return of the pain.

Conclusions: SRS and subsequent construction of new dentures after remission of the symptomatology was an effective treatment for TMD in the case described.     

Unilateral superior condylar neck fracture with dislocation in a child treated with an acrylic splint in the upper arch for functional repositioning of the mandible

Background: To present the outcomes for a case of unilateral mandibular subcondylar fracture with dislocation in an 11-year-old female treated with an acrylic splint for functional repositioning of the mandible.

Clinical presentation: A splint was placed in the upper arch to restore the functional repositioning of the mandible. The splint’s height was increased up to 5.5 mm on the side of the fracture to stimulate growth on the deficient side. To correct the mandibular asymmetry, a construction bite was made by 4 mm advancing. The total treatment time was 16 months. Long-term five-year follow up showed complete healing. A portion of the ramus appeared lateral with respect to the condylar head, whereas the mandibular deviation to the right side was fully corrected.

Conclusion: Conservative treatment may be an appropriate method for children in select cases, as they have an increased potential for spontaneous regeneration.     

Distraction of the temporomandibular joint condyle in patients with unilateral non-reducing disc displacement: Fact or fiction?

Objectives: This study investigated the distractive effect of a unilateral pivot splint on patients with unilateral disc displacement without reduction.

Methods: The study group was comprised of 18 patients who had no history of treatment with removable prosthetic restorations of molars, premolars, or canine teeth, and no previous treatment for temporomandibular disorder. Joint spaces measurements made on magnetic resonance images indicated the affected side to be narrower than the healthy side. Unilateral distraction splints were made for all patients. An ultrasonic motion analyzer was used to measure the vertical shift occurring on the affected side as patients closed their mouths with maximal force with the splint in their mouths.

Results: Closing with maximal force on the unilateral distraction splint led to a noticeable downward movement of the affected condyle.

Discussion: The findings of this study indicate that the TMJ condyle of patients with unilateral disc displacement without reduction may be unilaterally distracted if the articular space is narrowed.     

The efficacy of a specific stabilization splint

Background:

The use of a Tanner type stabilization splint, fabricated on a leaf gauge articulation for the treatment of patients with disc displacement without reduction, is lacking in the literature.

Objectives:

The purpose of the study is to collect non-controlled, therapy-related observations; in other words, to demonstrate the efficacy of this appliance for the treatment of patients with disc displacement without reduction.

Methods:

The study enrolled 55 patients, 5 men, and 50 women, with the clinical diagnosis disc displacement without reduction, 42 with and 13 without limited mouth opening. All patients received a splint in the musculoskeletally stable centric relation (CR) position. Mouth opening, clinical performance, and the timeframe of splint treatment were assessed.

Results:

For 37 patients with a disc displacement without reduction with limited opening, the largest increase in mouth opening (9·5±5·6 mm) occurred in the first week (7·9±2·5 days). No occlusal adjustment of the splint was needed during the treatment sequence. For three patients, treatment took up to 3 months (8·1%), for 13 patients, between 3 and 6 months (35·1%), and for 17 patients, within a year (45·9%), making a total of 89·1% successfully treated patients. Out of 50 patients, 29 had a total resolution of signs and symptoms, whereas 21 patients still suffered from solitary temporomandibular disorder (TMD) signs.

Conclusion:

A Tanner type stabilization splint, fabricated in the musculoskeletally stable CR position, appears to be an effective and efficient means for the treatment of patients with disc displacement without reduction. Its efficacy makes it eligible to be tested in a randomized controlled trial.

Clinical implications:

The efficacy of this specific splint, fabricated in the musculoskeletally stable CR position, makes it a promising tool to treat TMD patients with disc displacement without reduction.     

Clinical predictive factors for temporomandibular disorders following combined orthodontic and orthognathic surgical treatment in patients with Class III malocclusion

Objective: The aim of this study was to identify clinical factors predisposing to the development or worsening of temporomandibular disorders (TMDs) following orthodontic surgical treatment for Class III malocclusion.

Methods: A retrospective cohort study was performed on 88 patients with Class III malocclusion having undergone a combined orthodontic and orthognathic surgical treatment. Temporomandibular joint and masticatory muscle examinations were available prior to treatment and one year post-operatively. Multivariate logistic regression was used to predict the development of post-operative TMDs, and linear regression was used to predict the worsening of TMDs using Helkimo indices.

Results: Patients with Class III malocclusion presenting with pre-treatment anamnestic TMJ clicking (OR = 5.8; p = 0.03) and undergoing bimaxillary osteotomy procedures (OR = 18.6; p = 0.04) were more at risk for the development of TMDs.

Discussion: TMDs must be evaluated, monitored, and managed with caution in patients with Class III malocclusion presenting with pre-treatment joint clicking and who are planned for bimaxillary osteotomies.     

Patterns of cervical and masticatory impairment in subgroups of people with temporomandibular disorders–an explorative approach based on factor analysis

Objectives: To identify clinical patterns of impairment affecting the cervical spine and masticatory systems in different subcategories of temporomandibular disorder (TMD) by an explorative data-driven approach.

Methods: For this observational study, 144 subjects were subdivided according to Research Diagnostic Criteria for TMDs into: Healthy controls, temporomandibular joint (TMJ) signs without symptoms, TMJ affected, temporomandibular muscles affected, or TMJ and muscles affected. Factor analysis and linear regression were applied to cervical spine and masticatory data to identify and characterize clinical patterns in subgroups.

Results: Factor analysis identified five clinical dimensions, which explained 59% of all variance: Mechanosensitivity, cervical movement, cervical and masticatory dysfunction, jaw movement, and upper cervical movement. Regression analysis identified different clinical dimensions in each TMD subgroup.

Conclusion: Distinct clinical patterns of cervical spine and masticatory function were found among subgroups of TMD, which has clinical implications for therapeutic management.     

The effects of stabilization splint treatment on the volume of masseter muscle in sleep bruxism patients

Objective: The aim of this study was to evaluate, quantitatively, the volumetric effects of stabilization splint therapy on the masseter muscle of sleep bruxism (SB) patients.

Methods: The magnetic resonance (MR) images of 16 SB patients diagnosed by polysomnography (PSG) who used stabilization splints for four months were obtained before and after the therapy. The masseter muscle volume was calculated using Cavalieri’s principle on the MR images.

Results: After the splint therapy, the mean volume of the masseter muscle did not reduce significantly. The fat and/or water content of the muscles did not change either.

Discussion: The stabilization splint therapy had no effect on the volume, fat and/or water content of the masseter muscle; however the discomfort was reduced in the patients. Although the effect of splint therapy is not fully understood, the non-invasive and reversible stabilization splint can be used in SB patients because of its relaxation effect on muscles.     

Do TMJ symptoms improve and last across time after treatment with red (660 nm) and infrared (790 nm) low level laser treatment (LLLT)? A survival analysis

Objective: Temporomandibular disorder (TMD) is a variety of clinical problems that originate from the area of the temporomandibular joint (TMJ), masticatory muscles, and surrounding tissues. There are different treatment options; however, there is no evidence that low level laser treatment (LLLT) will last about six months. The aim of this study was to determine the survival rate of treatment with red (660 nm) and infrared (790 nm) laser in cases of TMDs.

Methods: In 19 subjects, one side of the face (half face) was randomly selected to receive intervention, in a total of 116 sensitive points. Pain was measured at baseline and time intervals of 24 h, 30, 90, and 180 days after treatment. Laser irradiation with 4 j/cm² in the TMJs and 8 j/cm² in the muscles was used in three sessions. Kaplan–Meier survival analysis and logistic regression were performed.

Results: Both treatments showed statistically significant results (p < 0.001). The survival rate for red and infrared laser was 0.24 and 0.30, respectively, at 180 days. Grinding teeth and headache were associated with recurrent pain.

Discussion: Both lasers were effective in the treatment of TMD symptoms and had a low survival rate at 180 days.     

Rare case of giant unicystic ameloblastoma: Luminal variant

Objective and importance: Ameloblastoma is a locally aggressive benign tumor, commonly occurring in the mandible. While giant ameloblastoma of multicystic or plexiform variant have been reported, the authors report a rare case of giant unicystic ameloblastoma of luminal variant, which was treated by compartmental resection and planned for delayed reconstruction.

Clinical presentation: A 46 year old male patient reported to the oral surgery out-patient department with a swelling of the left side mandible region of 2 years duration. He had undergone ayurvedic treatment for the same with no improvement. The size of the lesion on presenting was approximately 9 × 12 cm.

Intervention: Compartmental resection with plan for secondary reconstruction, after adequate follow up period.

Conclusion: While conservative management is being explored as a treatment option for unicystic ameloblastoma, resection is still the standard of care regardless of the histopathological subtype for giant lesions.     

Mandibular position influence on pilots’ postural balance analyzed under dynamic conditions

Objective: The aim of this study is to evaluate the influence of the mandibular position on the postural stability in a sample of civilian and military pilots.

Methods: Twenty military pilots (males, mean age 35.15 ± 3.14 years) and 17 civilian pilots (males, mean 34.91 ± 2.15 years) were enrolled in this study and underwent a Sensory Organization Test (SOT) using the EquiTest® (NeuroCom International Inc., Clackamas, OR, USA) computerized dynamic posturography. The composite parameter was recorded and analyzed.

Results: The equilibrium score (ES) recorded in centric occlusion is slightly higher than the ES recorded in mandibular rest position; civilian pilots showed ESs slightly higher than military pilots. The two-way ANOVA analysis shows these differences are not statistically significant.

Discussion: The findings of this study seem to suggest that the composite parameter of the SOT is not sensitive in analyzing the influence of the stomatognathic system on the postural balance of civilian and military pilots.     

Association between possible sleep bruxism and sleep characteristics in children

Aims: To evaluate the relationship between possible sleep bruxism and sleep characteristics in children.

Methodology: A cross-sectional study was conducted through data collection of a pre-tested questionnaire answered by 111 parents on behalf of their children in the waiting room during their appointment at the Pediatric Dentistry Clinic of a public Brazilian university. The diagnosis of possible sleep bruxism was based on the international classification of sleep disorders (ICSD) criteria. The Chi-square test and logistic multinomial regression test were used in the statistical analysis.

Results: The final model of logistic multinomial regression demonstrated that children with muscle pain in the mouth region (OR = 19.70 95% IC = 1.82–212.69), snoring (OR = 8.25 95% IC = 2, 56–26, 54), and those with parents with possible sleep bruxism have more of a probability of sleep bruxism.

Conclusion: Potential sleep bruxism tends to be hereditary. Muscle pain, snoring, and mouth breathing were important signals associated with possible sleep bruxism among children.     

Single-needle arthrocentesis (Shepard cannula) vs. double-needle arthrocentesis for treating disc displacement without reduction

Objectives: To compare single- vs. double-needle arthrocentesis with viscosupplementation for treating disc displacement without reduction of the temporomandibular joint.

Methods: Fifty-six patients with a magnetic resonance imaging diagnosis of non-reducing disc displacement were included. Arthrocentesis with viscosupplementation was performed on patients in group I using the Y-shaped needle (Shepard cannula) technique; the standard double-needle technique was performed on patients in group II. Patients were evaluated on postoperative day 1, and 1, 3, and 6 months later, patient- and procedure-related parameters were assessed.

Results: In both groups, significant improvement in the baseline levels was achieved (p < 0.01). Both techniques were equally effective at reducing pain and increasing the maximal mouth opening. The single-needle technique was easier to perform and required a shorter operative time (p < 0.01).

Discussion: Single-needle (Shepard cannula) arthrocentesis can be an alternative to the standard technique; however, it might add to the cost of the procedure.     

Prevalence of bruxism and temporomandibular disorders among orphans in southeast Uganda: A gender and age comparison

Objectives: The aims of the current study were: (1) to assess the prevalence of oral habits, bruxism, and temporomandibular disorders (TMDs) among children living in Uganda; (2) to establish whether parafunctional activities are associated with TMDs; and (3) to examine the possible impact of gender and age on the prevalence of bruxism, oral habits, and TMDs.

Methods: This study included 153 children aged 6–17 years. The study consisted of a questionnaire and a clinical examination.

Results: TMDs were moderately prevalent (35%). Parafunctional habits were performed by 93% of the participants. When performed extensively, they were significantly related to myalgia. No gender or age significant differences were found.

Conclusions: 1. Only extensive masticatory parafunctional oral activity is significantly related to myalgia. 2. Gender and age had no impact on the prevalence of bruxism, oral habits, or TMDs. 3. Sleep and awake bruxism were not related to anamnestic symptoms or clinical findings in TMD.     

Optimal duration of ultra low frequency-transcutaneous electrical nerve stimulation (ULF-TENS) therapy for muscular relaxation in neuromuscular occlusion: A preliminary clinical study

Objectives: The primary aim of this work was to determine the duration of ultra-low-frequency transcutaneous electrical nerve stimulation (ULF-TENS) application necessary to achieve sufficient relaxation of the masticatory muscles. A secondary aim was to analyze the influence of stimulation on muscle relaxation in pathological subjects and determine whether ULF-TENS has a noteworthy impact on muscle relaxation.

Methods: Sixteen adult subjects with temporomandibular disorders (TMD) and muscle pain and a group of four control subjects were included in this study. ULF-TENS was applied, and muscular activities of the masseter, temporal, and sternocleidomastoid muscles (SCM) were recorded for 60 min.

Results: Significant relaxation was achieved in the TMD group from 20, 40, and 60 min for the temporal, masseter, and SCM muscles (p < 0.05), respectively. Maximum relaxation was achieved in 12.5% of the subjects after 20 min, in a further 12.5% after 40 min, and in the remaining 75% after 60 min. Significant relaxation was achieved in the control group from 20 to 40 min for the masseter and temporal muscles, respectively (p < 0.05).

Discussion: Taken together, the results suggest that an ideal ULF-TENS application would last 40 min to obtain sufficient muscle relaxation both in patients with masticatory system disorders and healthy subjects, a time constraint that is consistent with everyday clinical practice.     

Modulation of the masticatory path at the mandibular first molar throughout the masticatory sequence of a hard gummy jelly in normal occlusion

Objective: In this study, the authors investigated the modulation of the masticatory path at the mandibular first molar during natural chewing of a hard gummy jelly in adults with normal occlusion.

Methods: The unilateral mastication sequence was divided into three stages, and the masticatory path of the mandibular first molar on the working side was analyzed at 2.0, 3.0, 4.0, and 5.0 mm vertical slice levels below the intercuspation in the frontal and sagittal views.

Results: In the frontal view, the closing and opening angles and cycle width of the final stage at 3.0, 4.0, and 5.0 mm slice levels were smaller and narrower than those of the initial stage, although those at the 2.0 mm slice level were little changed.

Discussion: Masticatory paths of the mandibular first molar at slice levels greater than 3.0 mm were evidently modulated to adapt to the changing properties of the food, and those at the 2.0 mm slice level remained stable throughout the masticatory sequence.     

A new device for measuring isometric force of the craniocervical flexor and extensor muscles and its reliability

Objective: Craniocervical (CC) muscles control posture of the CC area. Muscle imbalance at this area induces musculoskeletal disorders. The purpose of this study was to develop a device for measuring isometric force of CC flexor and extensor muscles and to evaluate its intra-rater reliability.

Method: Isometric force of CC flexor and extensor muscles was measured in 20 women by one examiner on two days with a custom-made device. The intra-class correlation coefficient (ICC), standard error of measurements (SEM), smallest detectable difference (SDD), and Pearson correlation coefficient were computed.

Results: The results of this study revealed that this device had excellent reliability (ICC: 0.98, SEM: 2.29 N, SDD: 6.36 N, Pearson correlation coefficient: 0.97 for CC flexor muscles and ICC: 0.97, SEM: 2.13 N, SDD: 5.91 N, Pearson correlation coefficient: 0.94 for CC extensor muscles).

Discussion: This new device can improve knowledge about the CC muscle and efficacy of treatments in patients with poor posture.     

Thirty-year follow-up of a TMD case treated based on the neuromuscular concept

Aim:

Occlusal therapy is employed to alleviate the symptoms of a temporomandibular disorder (TMD) at times. However, the long-term effect of occlusal therapy in the masticatory system is not well understood. This case study aims to present a 30-year follow-up of a TMD case.

Methodology:

The patient developed TMD with intermittent closed lock of the left temporomandibular joint (TMJ). Chief complaints included trismus, pain, and noise of the left TMJ during function. The patient’s occlusal disharmony was assessed with use of electronic instruments and corrected based on the neuromuscular concept. A minimum-invasive and reversible approach using adhesive occlusal restorations was used.

Results:

The jaw movement and masticatory muscle activity assessed at the 7- and 23-year follow-ups revealed that the established occlusion was well adapted, and re-established the patient’s functional occlusion system. The patient has been free from TMD symptoms with the corrected occlusion for 30 years.

Conclusions:

Occlusal reconstruction based on the neuromuscular concept can be stably integrated into the patient’s functional occlusion system.