Effect of a prefabricated anterior bite stop on electromyographic activity of masticatory muscles

Structured critical analysis correction of a systematic review

OBJECTIVE

: Systematic reviews (SRs) are an increasingly important format in the scientific literature. Commentaries on improvements to the SR format have focused on methodological quality, but a greater concern is a frequent lack of critical analysis. A structured critical analysis (SCA) was described as a solution to this deficiency.

METHODS

: Recommendations and conclusions of a recent SR were analyzed with a SCA to address common problems previously reported with the SR format.

RESULTS

: Errors in the component studies and their interpretation by the SR that led to erroneous recommendations were presented. The 5-part SCA provided comprehensive analysis that corrected the SR, which had accepted the component study conclusions verbatim.

CONCLUSION

: The SCA is a logical approach to provide critical thinking in SRs to ensure appropriate conclusions. This is especially important, as many SRs report contradictory evidence. Also, the reader can use the SCA format to better understand existing literature.

Centric relation and increasing the occlusal vertical dimension: concepts and clinical techniques - part two

Part one of this article considered the theoretical and clinical aspects of recording centric relation using established techniques, and presented a range of methods available all with advantages and limitations. This second article will consider more recent concepts in recording centric relation and practical aspects of increasing the occlusal vertical dimension.

[Bruxism: Classification, Diagnostics and Treatment]

Bruxism: Classification, Diagnostics and Treatment Abstract. Bruxism, the grinding or clenching of teeth, is common in the population. Stress, anxiety syndromes and genetic disposition seem to be dominant factors that lead to increased muscle tension. A distinction is made between two circadian manifestations, sleep and wake bruxism. Bruxism is a major risk factor for tooth structure and dentures. The diagnosis is based on a targeted medical history and examination. Sleep bruxism can be demonstrated by electromyography and video recording in the sleep laboratory. The treatment aims to protect the hard tooth substance and preserve the denture using occlusal splints. Relaxation exercises can improve bruxism. Specialized physiotherapy can improve tension, pain and restricted movement. Botulinum toxin treatment reduces the subjective complaints during the period of action.

Amitriptyline and intraoral devices for migraine prevention: a randomized comparative trial

OBJECTIVES

Nonpharmacological treatments, such as the Nociceptive Trigeminal Inhibition Tension Suppression System (NTI-tss), are approved for migraine prophylaxis. We aimed at evaluating the effectiveness of the NTI-tss and to compare its efficacy with amitriptyline and with a sham intraoral device in the preventive treatment of migraine.

METHODS

Consecutive patients with migraine were randomized to receive 25 mg of amitriptyline/day (n = 34), NTI-tss (n = 33) and a non-occlusal splint (n = 30). The headache frequency was evaluated at six and 12 weeks.

RESULTS

The amitriptyline group showed, respectively, 60% and 64% reduction in attack frequency at six and 12 weeks (P = 0.000). In the NTI-tss and non-occlusal splint groups, reduction was 39% and 30%, respectively, at six weeks and 48% for both groups at 12 weeks.

CONCLUSIONS

Amitriptyline proved superior to the NTI-tss and the non-occlusal splint. Despite its approval by the United States Food and Drug Administration, the NTI-tss was not superior to a sham device.

Clinical protocol for occlusal adjustment: Rationale and application

BACKGROUND

Occlusal adjustment can optimize the result of orthodontics, orthognathic surgery, and comprehensive restoration, and resolve adverse forces to the dentition that affect the entire masticatory system. Mounted diagnostic casts and computerized occlusal analysis offer complementary advantages for evaluating occlusal problems. Predictable occlusal adjustment is facilitated by precise, measured documentation of occlusal force by computerized occlusal analysis.

CLINICAL PRESENTATION

A conservative, structural correction of a pronounced, chronic occlusal problem by additive and subtractive occlusal adjustment was performed after a previous failed occlusal adjustment. The patient's chief concerns were significant anterior teeth fremitus in maximum intercuspation and "pain in the teeth and a poor bite" after 30+ adjustments over 2.5 years.

CLINICAL RELEVANCE

Confirmation of specific criteria for a therapeutic occlusion resolved the anterior teeth fremitus and uneven bite. Traumatic occlusal contact on posterior teeth may elicit protective mandibular repositioning affecting anterior teeth relationships and should be considered during comprehensive diagnosis.

Evaluation of sleep bruxism with a novel designed occlusal splint

PURPOSE

This report presents our evaluation system that assesses sleep bruxism. The characteristics and fabrication process of our novel designed splint, and the analysis process of our system are presented.

METHODS

The subjects were 17 volunteers. The splint was fabricated with a self-curing resin compounded with an amino-acid powder for easy wear on the semi-adjustable articulator, and adjusted for a full-balanced occlusion. An impression of the splint, located on the cast, was taken before and after it was worn. The analytical casts were made and scanned via a dental 3D scanner. The datasets were superimposed using two kinds of regions of interest (palate and occlusal surface). The differences between the two datasets were quantitatively presented with pseudo-color mapping. The maximum differences in coronal and apical directions were calculated on the selected area in the occlusal surface when the occlusal surface was used as a region of interest for registration. The relationship between the EMG activities and the change of occlusal surface of the splint were investigated.

RESULTS

In all subjects, deformation and wear facets on the splint were observed. The differences in the apical direction, which indicate wear depth, were correlated with the maximum muscle activity during sleep (p=0.036).

CONCLUSION

From our results, it is suggested that we are not able to eliminate the influence of parafunction for the prosthesis only by designing the surface of occlusal splint using the semi-adjustable articulator. Our splint may have the potential to detect specific facets due to parafunctions as nocturnal bruxism.

Effectiveness of two different splints to treat temporomandibular disorders

Nearly 5% of the the world's population has temporomandibular disorder (TMD) severe enough to make them seek treatment. A third of the total population has at least one TMD symptom. There are different types of splints to treat TMD. In our study, we compared the success of two different appliances [stabilization splint (ss), nociceptive trigeminal inhibition splint (NTI)] by using Fonseca's questionnaire, the OHQoL-UK and visual analog scale (VAS). A total of 40 patients suffering from TMD were included in this study and answered questionnaires twice, at the beginning of the treatment and 3 months later. Regarding TMD alone, 39 patients (97.5%) had some degree of the disorder, 7 of of these cases being mild (17.5%), 15 moderate (37.5%), and 17 severe (42.5%). We analyzed posttreatment changes compared to baseline. Pain complaints decreased in both groups, and the OHQoL-UK revealed better quality of life after treatment. Based on the posttreatment Fonseca's questionnaires, significant changes in the patients' complaints in the group SS (p < 0.01) were observed. The group NTI also displayed changes but these were not statistically significant after treatment (p > 0.05). Patients in both groups had fewer TMD complaints after TMJ treatment. According to the Fonseca's questionnaire, the patients' major TMD complaint was clenching-grinding, followed by pain in the craniomandibular joint, or earache.

The NTI-tss device for the therapy of bruxism, temporomandibular disorders, and headache - where do we stand? A qualitative systematic review of the literature

BACKGROUND

The NTI-tss device is an anterior bite stop, which, according to the manufacturer, is indicated for the prevention and treatment of bruxism, temporomandibular disorders (TMDs), tension-type headaches, and migraine. The aim of this systematic review was to appraise the currently available evidence regarding the efficacy and safety of the NTI-tss splint.

METHODS

We performed a systematic search in nine electronic databases and in NTI-tss-associated websites (last update: December 31, 2007). The reference lists of all relevant articles were perused. Five levels of scientific quality were distinguished. Reporting quality of articles about randomized controlled trials (RCTs) was evaluated using the Jadad score. To identify adverse events, we searched in the identified publications and in the MAUDE database.

RESULTS

Nine of 68 relevant publications reported about the results of five different RCTs. Two RCTs concentrated on electromyographic (EMG) investigations in patients with TMDs and concomitant bruxism (Baad-Hansen et al 2007, Jadad score: 4) or with bruxism alone (Kavakli 2006, Jadad score: 2); in both studies, compared to an occlusal stabilization splint the NTI-tss device showed significant reduction of EMG activity. Two RCTs focused exclusively on TMD patients; in one trial (Magnusson et al 2004, Jadad score: 3), a stabilization appliance led to greater improvement than an NTI-tss device, while in the other study (Jokstad et al 2005, Jadad score: 5) no difference was found. In one RCT (Shankland 2002, Jadad score: 1), patients with tension-type headache or migraine responded more favorably to the NTI-tss splint than to a bleaching tray. NTI-tss-induced complications related predominantly to single teeth or to the occlusion.

CONCLUSION

Evidence from RCTs suggests that the NTI-tss device may be successfully used for the management of bruxism and TMDs. However, to avoid potential unwanted effects, it should be chosen only if certain a patient will be compliant with follow-up appointments. The NTI-tss bite splint may be justified when a reduction of jaw closer muscle activity (e.g., jaw clenching or tooth grinding) is desired, or as an emergency device in patients with acute temporomandibular pain and, possibly, restricted jaw opening.

The influence of the leaf gauge and anterior jig on jaw muscle electromyography and condylar head displacement: a pilot study

BACKGROUND

A leaf gauge and an anterior jig may be used to assist the recording of a reproducible jaw position for restorative and prosthodontic treatment. This study investigated possible condylar displacement using an opto-electronic jaw-tracking device and a leaf gauge or anterior jig. The effect of a leaf gauge and anterior jig on jaw muscle electromyography was also examined.

METHODS

Five healthy adults without symptoms of temporomandibular disorders were selected. Condylar displacement during clenching were recorded simultaneously with electromyographic activity of superior and inferior heads of the lateral pterygoid, anterior and posterior temporalis, masseter, and suprahyoid muscles. Subjects were trained to bite at maximum and half-maximum bite-force using an anterior jig incorporating a force transducer.

RESULTS

No consistent condylar displacement was observed in x, y and z axes between different bite-forces although there was a trend towards superior displacement. Comparison of maximum intercuspal clench and maximum clench on a leaf gauge and an anterior jig produced significant decrease in anterior temporalis activity (p < 0.05), whilst an anterior jig with maximum clench significantly decreased posterior temporalis muscle activity.

CONCLUSION

Within the limits of this pilot study, no consistent change in condylar position was identified with these appliances.