Steven Bender DDS
Randomized controlled trials (RCTs) suggest that the NTI-tss device may be used successfully for the management of bruxism and temporomandibular joint disorders (TMDs) in selected patients.
Evidence supports the use of the NTI-tss oral device for the management of bruxism and TMDs, however, the authors recommend patient compliance with follow-up control sessions to avoid potential adverse events.
What is the current available data for the effectiveness of the NTI-tss device for the treatment of bruxism, headache and temporomandibular disorders? What are the documented complications or side effects of the use of the NTI-tss?
The authors conducted a systematic search of nine electronic databases, the NTI-tss website and the reference lists of all relevant articles through December 31, 2007. They also reviewed relevant textbooks on the topics of TMDs, occlusion and bruxism, and contacted the Swiss and European providers of the NTI-tss device to request any additional publications that may be available. They distinguished five levels of scientific quality and evaluated RCT articles according to the quality score developed by Jadad et al. The authors also carried out a specific search of the U.S. Food and Drug Administration's (FDA) Manufacturer and User Facility Device Experience Database (MAUDE) to identify complications and side effects associated with the use of the NTI-tss device.
The authors identified a total of 68 relevant publications, 39 of which were from the electronic databases and related websites. They did not identify any systematic reviews of RCTs among the relevant studies. Thirteen of the contributions reported results of clinical studies. Nine of these publications referred to five RCTs of level 2 quality according to the scoring system developed by Jadad et al . They classified four studies as level 3 and 12 as level 4. Forty-three publications were classified as level 5 which represented narrative reviews, editorials, commentaries and interviews . Of the 68 relevant publications, all but two were written in English. Four of the RCTscompared the therapeutic performance of a complete-arch, hard acrylic resin occlusal stabilization appliance, which was worn at night, to the NTI-tss. In the other trial, researchers compared a full-coverage occlusal splint, similar to a bleaching tray, to the NTI-tss. Two RCTs studied electromyographic (EMG) activity of jaw-closing muscles. In both studies the NTI-tss device showed significant reduction of EMG activity compared to an occlusal stabilization splint. Two other RCTs focused exclusively on patients with TMD. One trial suggested that a stabilization appliance led to greater improvement than an NTI-tss device. While the other found no difference between the two. The authors of two of the RCTs observed no adverse events while authors of three other trials documented complications. Authors of two other trials noted two additional complications. The systematic review documented one adverse outcome described in a book chapter and five different adverse events listed on the FDA Medical Device reporting website. According to the systematic review, no report of aspiration could be found.
Evidence from RCTs supports the use of the NTI-tss appliance for the management of TMDs and bruxism, but to avoid complications, the authors recommend that use be limited to patients compliant with follow-up appointments. This review supports the judicious use of the NTI-tss oral appliance for patients with acute, painful temporomandibular joints who may require a treatment modality that can be implemented quickly and in instances where a reduction in EMG activity of the closing muscles during tooth clenching or grinding is desired.
Source of Funding:
Importance and Context:
The NTI-tss device is a small, prefabricated or laboratory made intra-oral device that covers the two mandibular or maxillary central incisors and allows for contact of the opposing central incisors only. Since its FDA approval in 1998, controversy has persisted concerning the therapeutic benefits and potential dangers of its use. The manufacturer recommends that the appliance be utilized for the treatment of bruxism, temporomandibular disorders and headaches. Articles in both the lay press and the dental literature have reported the positive effects associated with the use of the NTI-tss device. Other researchers have raised doubts about the appliance; warning of the potential for adverse events such as appliance aspiration, ingestion and permanent occlusal changes after prolonged and unmonitored use. This study is the first systematic review to examine the NTI-tss for effectiveness and safety.
Strengths and Weaknesses of the Systematic Review:
This review used accepted search methods to identify, select, and classify all appropriate studies that could potentially answer the two clinical questions. However, the authors only used RCTs to formulate the conclusions. Due to the reported methodological weaknesses of the RCTs, the authors might have considered including studies of lesser quality to obtain a larger volume of data concerning the original questions, especially regarding the effectiveness of the NTI-tss splint. The review appropriately pointed out that there are inherent risks of side effects associated with the use of any intra-oral appliance such as an increase of clenching activity when wearing the splint, unintended occlusal changes after full-time usage, increase or decrease in salivation, and tension in the teeth from wearing a poor-fitting appliance.
Strengths and Weaknesses of the Evidence:
The inability to design a double blind study involving intra-oral appliances creates limitations to the quality of the findings. Differing inclusion criteria, small sample sizes and the lack of standardized diagnostic criteria also limited the quality of the included evidence. The authors reported that the non-controlled studies had the potential for optimistic (false positive) conclusions and, thus, were not included in the review. The evidence pertaining to adverse events was clear and no incidences of appliance aspiration could be identified in the Food and Drug Administration’s (FDA) Manufacturer and User Facility Device Experience Database (MAUDE) database.
Implications for Dental Practice:
Since its FDA approval in 1998, the NTI-tss device has earned both praise and criticism in the lay and dental press. In light of the conflicting reports concerning the NTI-tss, this systematic review is timely. The authors considered only the best available evidence to establish their conclusions and determined that the NTI-tss splint could be beneficial when treating patients for clenching and bruxism. The review also suggests that the NTI-tss splint may benefit patients with symptoms of temporomandibular disorders and possibly those with headaches. The literature is not conclusive as to the role of EMG activity and its relevance to pain. When considering bite splint therapy of any type, dentists are advised to take into consideration the patient's willingness to comply with instructions and return as recommended for follow-up care to avoid potential adverse effects.