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BMC Oral Health
Open Access
Research article
The NTI-tss device for the therapy of bruxism, temporomandibular
disorders, and headache – Where do we stand? A qualitative
systematic review of the literature
Henrike Stapelmann1 and Jens C Türp*1,2
Address: 1Clinic for Reconstructive Dentistry and Temporomandibular Disorders, Dental School, Hebelstrasse 3, 4056 Basel, Switzerland and
2Interuniversity College for Health and Development Graz/Castle of Seggau, Austria
Email: Henrike Stapelmann - h.stapelmann@unibas.ch; Jens C Türp* - jens.tuerp@unibas.ch
* Corresponding author
Abstract
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 (Kavaklı 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.
Published: 29 July 2008
BMC Oral Health 2008, 8:22 doi:10.1186/1472-6831-8-22
Received: 7 February 2008
Accepted: 29 July 2008
This article is available from: http://www.biomedcentral.com/1472-6831/8/22
© 2008 Stapelmann and Türp; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
BMC Oral Health 2008, 8:22 http://www.biomedcentral.com/1472-6831/8/22
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Background
In July 1998, the U.S. Food and Drug Administration
(FDA) granted approval for the "NTI Clenching Suppres-
sion System" (now: "Nociceptive Trigeminal Inhibition
Tension Suppression System": NTI-tss). According to the
manufacturer, the NTI-tss device is indicated for the pre-
vention and treatment of bruxism, temporomandibular
disorders (TMDs), occlusal trauma, tension-type head-
aches and/or migraine [1].
The NTI-tss device is a small pre-fabricated anterior bite
stop (Figure 1) which covers – in its most widely used
form – the two maxillary (or mandibular) central incisors
(Figure 2). The fit along the teeth is accomplished at the
chair side by filling either an autopolymerizing acrylate or
a thermoplastic material into the base of the device, which
is subsequently adapted along the central incisors, thereby
increasing the vertical dimension between the upper and
lower jaw. Adjustments along the outer surface of the bite
stop are made by the dentist to ensure that at jaw closure
and during excursive movements tooth contacts are
present only between the intraoral device and the incisal
embrasures of the antagonistic teeth. This "miniature
anterior bite appliance" [2] is typically worn during the
night, although two variations of the bite stop are offered
for daytime use [3].
In the lay press, most articles have reported positively
about the NTI-tss splint in the therapy of long-lasting
headache or facial pain [e.g., [4-6]]. Likewise, excited den-
tal practitioners have published their personal impres-
sions in local dental journals [e.g., [7]] or on the website
of the international NTI-tss provider e-motion [3].
Conversely, some renowned clinical researchers [e.g., [8-
12]] have tempered over-optimistic expectations by rais-
ing doubts on the claimed success and by pointing at the
possibility of unwanted side effects, such as aspiration,
ingestion, occlusal changes after prolonged unmonitored
use, and mobility of anterior teeth. In 2003, Helkimo [8]
delivered an expert statement on demand of the Swedish
Dental Association and the Swedish National Board of
Health and Welfare on the question whether the use of the
NTI-tss device "is to be regarded as lege artis and accord-
ing to science and empirical experience, both as to the
treatment of stomatognathic problems as well as
migraine." The author came to the conclusion that there is
a "total lack of scientific documentation of its therapeutic
effects and possible unwanted side-effects" [8]. As far as
side effects are concerned, Jokstad et al [10] mentioned
that one person in Norway [13] and three individuals in
the United States were subjected to medical emergencies
due to aspirated NTI-tss devices splints. For the three cases
from the U.S., the author referred to the FDA's Manufac-
turer and User Facility Device Experience Database
(MAUDE), which contains voluntary, user facility, distrib-
utor, and manufacturer reports of adverse events involv-
ing medical devices. Later, Wright and Jundt [12] repeated
the contention of four aspirated NTI-tss devices by refer-
ring Jokstad et al's article [10].
Considering the controversy that exists within parts of the
international dental community regarding the benefits
and dangers of the NTI-tss device, it appears to be timely
to
(a) systematically review the (dental) literature in order to
summarize and appraise the currently available data on
the efficacy and/or effectiveness of the NTI-tss device, and
(b) to summarize all identifiable documented cases, in
which complications and/or side effects associated with
The NTI-tss device, standard type (left) and vertically reduced type (right)Figure 1
The NTI-tss device, standard type (left) and vertically
reduced type (right).
Inserted NTI-tss deviceFigure 2
Inserted NTI-tss device.
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this anterior bite stop have been reported in the dental lit-
erature.
Methods
Identification of publications about the efficacy and/or
effectiveness of the NTI-tss device
To identify a maximum number of relevant publications
(including dental congress abstracts), we performed a sys-
tematic search in the following electronic databases:
1. The Cochrane Library
2. PubMed
3. TRIP database
4. MEDPILOT.DE
5. BIREME
6. The database of the Deutscher Ärzte-Verlag, which com-
prises the four German-language dental journals "Deut-
sche Zahnärztliche Zeitschrift", „Zeitschrift für
Zahnärztliche Implantologie“, „Oralprophylaxe &
Kinderzahnheilkunde“, and „Zahnärztliche Mitteilungen“
7. The database of the Quintessenz Verlag, which consid-
ers the seven German-language dental journals "Die
Quintessenz", „Kieferorthopädie“, „Parodontologie“,
„Implantologie“, „Endodontologie“, „Quintessenz Team-
Journal“ and „Quintessenz Zahntechnik“
8. Google Scholar
9. Web of Science (Cited reference search)
The key words and strategies for the searches in each of the
nine databases are shown in Tables 1 to 9. Moreover, were
searched NTI-tss-associated websites for relevant articles
and references.
The last update of all electronic searches was carried out
on December 31, 2007.
In addition to the database search, textbooks related to the
topics of TMDs, occlusion, and bruxism were considered.
Furthermore, the Swiss provider (Karr Dental) and an
international European provider of the NTI-tss device (e-
motion) were requested to send us possible further mate-
rial and publications. The abstracts, or, when available,
the full-text papers were read in order to establish the
acceptability of the publications to this review. Finally, the
reference lists of the identified relevant articles were
screened to find additional pertinent contributions (e.g.,
journal articles, textbooks, book chapters, master or doc-
toral theses, course material).
The strength of evidence related to the identified publica-
tions was evaluated using the classification suggested by
Antes [14] (Table 10). Articles about randomized control-
led trials (RCTs) were evaluated according to the quality
score developed by Jadad et al [15]. The Jadad scale con-
sists of five items, which focus on three dimensions of
internal validity (randomization; double blinding;
description of withdrawals and drop-outs) (Table 11).
Since double-blinding (as required in the Jadad scale) is
not possible when occlusal devices are used, single-blind-
ing of the investigator(s) to the type of splint worn by the
patient was used as criterion.
Uncertainties on data interpretation and discrepancies in
scoring according to the classifications by Antes [14] as
well as Jadad et al [15] were resolved by discussion
between the two reviewers.
Identification of publications about complications and/or
side effects of the NTI-tss device
For the identification of complications and/or side effects
associated with the use of the NTI-tss device, pertinent
reports found in the identified articles using the search
strategies mentioned above were considered.
Table 1: The Cochrane Library.
# Search terms Hits Relevant hits Cumulative relevant hits Reference
1NTI 10 2 2 [9,10]
2NTI-tss 0
3 NTI* Cochrane reviews: 11 0
clinical trials: 37 2 2
methodological studies: 2 0
economic evaluation: 1 0
4 nociceptive trigeminal inhibition 5 4 5 [16-18]
5 nociceptiv* trigeminal inhibition 6 5 5
6 anterior deprogrammer 0
Search strategy and results (search date: December 31, 2007)
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Table 2: PubMed.
# Search terms Hits Relevant hits Cumulative relevant hits (New) Relevant references
1NTI 195 7 7 [9,10,12,22,60-62]
2 NTI-tss 0
3NTI* 355 7 7
4 nociceptive trigeminal inhibition 107 4 10 [16-18]
5 nociceptiv* trigeminal inhibition 108 5 10
6 anterior deprogrammer 2 0
7 "Temporomandibular Joint Disorders"[MeSH] AND NTI 7 7 10
8 "Temporomandibular Joint Disorders"[MeSH] AND NTI-tss 0
9 "Temporomandibular Joint Dysfunction Syndrome"[MeSH] AND NTI 0
10 "Temporomandibular Joint Dysfunction Syndrome"[MeSH] AND NTI-tss 0
Clinical queries; therapy, broad sensitive search:
11 (NTI) AND ((clinical [Title/Abstract] AND trial [Title/Abstract]) OR clinical trials
[MeSH Terms] OR clinical trial [Publication Type] OR random* [Title/Abstract] OR
random allocation [MeSH Terms] OR therapeutic use [MeSH Subheading])
42 4 10
12 (NTI-tss) AND ((clinical [Title/Abstract] AND trial [Title/Abstract]) OR clinical trials
[MeSH Terms] OR clinical trial [Publication Type] OR random* [Title/Abstract] OR
random allocation [MeSH Terms] OR therapeutic use [MeSH Subheading])
0
13 (NTI*) AND ((clinical [Title/Abstract] AND trial [Title/Abstract]) OR clinical trials
[MeSH Terms] OR clinical trial [Publication Type] OR random* [Title/Abstract] OR
random allocation [MeSH Terms] OR therapeutic use [MeSH Subheading])
98 4 10
14 (Nociceptive trigeminal inhibition) AND ((clinical [Title/Abstract] AND trial [Title/
Abstract]) OR clinical trials [MeSH Terms] OR clinical trial [Publication Type] OR
random* [Title/Abstract] OR random allocation [MeSH Terms] OR therapeutic use
[MeSH Subheading])
25 4 10
15 (Nociceptiv* trigeminal inhibition) AND ((clinical [Title/Abstract] AND trial [Title/
Abstract]) OR clinical trials [MeSH Terms] OR clinical trial [Publication Type] OR
random* [Title/Abstract] OR random allocation [MeSH Terms] OR therapeutic use
[MeSH Subheading])
26 5 10
16 (Anterior deprogrammer) AND ((clinical [Title/Abstract] AND trial [Title/Abstract])
OR clinical trials [MeSH Terms] OR clinical trial [Publication Type] OR random*
[Title/Abstract] OR random allocation [MeSH Terms] OR therapeutic use [MeSH
Subheading])
0
Search strategy and results (search date: December 31, 2007)
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Table 3: TRIP database.
# Search terms Hits Relevant
hits Cumulative relevant
hits (New) Relevant
references
1 NTI evidence-based Synopses: 1 0
guidelines: 2 0
clinical questions: 1 0
E-textbooks: 1 0
other: 1 0
Medline:
therapy: 9 3 3 [9,10,22]
diagnosis: 8 0
systematic reviews: 4 0
prognosis: 8 0
etiology: 5 0
2NTI-tss 0 0 3
3 NTI* systematic reviews: 207 0
evidence-based synopses: 17 0
guidelines: 33 0
clinical questions: 33 0
E-textbooks:19 0
More: 3 0
Medline:
therapy: 16 3 3
diagnosis: 11 0
systematic reviews: 26 0
prognosis: 16 0
etiology: 15
4 nociceptive trigeminal
inhibition
systematic reviews: 1 0
Guidelines: 3 0
E-textbooks: 9 0
Medline:
therapy: 6 4 6 [16-18]
diagnosis: 2 0
systematic reviews: 0
prognosis: 1 0
etiology: 0
5 nociceptiv* trigeminal
inhibition
systematic reviews: 1 0
guidelines: 3 0
E-textbooks:9 0
Medline:
therapy: 8 5 6
diagnosis: 2 0
systematic reviews: 0 0
prognosis: 1 0
etiology: 0
6 anterior deprogrammer 0
Search strategy and results (search date: December 31, 2007)
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Table 4: MedPilot.
# Search terms Hits Relevant hits Cumulative relevant hits (New) Relevant references
1 NTI All: 396
Medline: 357 7 7 [9,10,12,22,60-62]
in others 5 0
2NTI-tss 0
3 NTI* 825 Medline: 538 (see PubMed search)
4 nociceptive trigeminal inhibition 157 Medline: 156 4 10 [17,16,18]
5 nociceptiv* trigeminal inhibition 157 Medline: 156 4 10
6 anterior deprogrammer Medline: 4 0 10
Search strategy and results (search date: December 31, 2007)
Table 5: BIREME.
# Search terms Hits Relevant hits Cumulative
relevant hits
(New) Relevant references
1 NTI General Health Sciences (190):
LILACS: 5 0
Medline: 161 (see PubMed search)
Cochrane Library: 23 0
SciELO: 1 0
Specialized Areas (1):
BBO: 1 0
International Agencies (1):
WHOLIS: 1 0
2NTI-tss 0
3NTI* 0
4 nociceptive trigeminal
inhibition
General Health Sciences (114):
Medline: 102 (see PubMed search)
Cochrane Library: 12 0
5 nociceptiv* trigeminal
inhibition
0
6 anterior deprogrammer General Health Sciences (3):
LILACS: 1 0
Medline: 2 0
Search strategy and results (search date: December 31, 2007)
Table 6: Database of the Deutsche Ärzte Verlag.
# Search terms Hits
1NTI 0
2 NTI-tss 0
3NTI* 0
4 nociceptive trigeminale Inhibition 0
5 nociceptiv* trigeminale Inhibition 0
6 anteriorer Deprogrammierer 0
Search strategy and results (search date: December 31, 2007)
Table 7: Database of the Deutsche Quintessenz Verlag.
# Search terms Hits
1 NTI 3062
2 NTI-tss 0
3NTI* 0
4 nociceptive trigeminal inhibition 0
5 nociceptiv* trigeminal inhibition 0
6 anterior deprogrammer 0
Search strategy and results (search date: December 31, 2007)
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Table 8: Google Scholar.
# Search terms Hits Relevant hits Cumulative relevant hits (New) Relevant references
1 NTI about 95,000
2 NTI-tss 28 18 18 [1,3,8,10,16,24,26,36,63-72]
3NTI* 93,400
4 nociceptive trigeminal inhibition 8,760
5 nociceptiv* trigeminal inhibition 18 2 20 [10,19]
6 anterior deprogrammer 37 2 20
Search strategy and results (search date: December 31, 2007)
Table 9: Web of Science: Cited reference search.
# Search terms Times cited Relevant hits Cumulative relevant hits (New) Relevant references
1 Baad-Hansen (2007) 0
2 Aristeguieta (2006) 0
3 Wright (2006) 0
4 Jokstad (2005) 3 1 1 [22]
5 Magnusson (2004) 5 2 2 [10]
6 Shankland WE (2002) N.N.
7 Shankland WE (2001) N.N.
Search strategy and results (search date: December 31, 2007). N.N.: nomen nescio (unknown author)
Table 10: Hierarchy of strength of evidence for therapeutic decisions [slightly modified after [14]]
Level Description
I Systematic review of randomized controlled trials (RCTs)
II Article about an RCT
III Article about an experimental study without randomization; cohort study; case-control-study
IV Article about a non-experimental study (cross-sectional study; case series; case report)
V Narrative review or expert opinion
(based on clinical experience) without explicit clinical appraisal (e.g., statements, editorials; expert commentaries to published articles;
interviews with experts, brief references to NTI-tss in articles; commercial-like reviews)
Table 11: Determination of the quality score proposed by Jadad et al [15]
Articles are assessed according to the following questions:
• Was the study described as randomized?
• Was the study described as double blind?
• Was there a description of withdrawals and dropouts? (The number and the reasons for withdrawal in each group must be stated. If there were
no withdrawals, it should be stated in the article.)
A score of 1 point is given for each "yes," a score of 0 points is given for each "no."
• One additional point is given if for question 1 the method to generate the sequence of randomization was described and it was appropriate (i.e., if it
allowed each study participant to have the same chance of receiving each intervention and the investigators could not predict which treatment was
next).
• One additional point is given if for question 2 the method of double blinding was described and it was appropriate (i.e., if it is stated that neither the
person doing the assessments nor the study participant could identify the intervention being assessed, or in the absence of such a statement the use
of active placebos, identical placebos, or dummies is mentioned).
• One point is deducted if for question 1 the method to generate the sequence of randomization was described and it was inappropriate (e.g., patients
were allocated alternately).
• One point is deducted if for question 2 the method of double-blinding was described and it was inappropriate.
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In addition, a specific search in the FDA's Manufacturer
and User Facility Device Experience Database (MAUDE)
was carried out with the following strategy: Go to Simple
Search → Search term: NTI; Date Report Received by FDA:
ALL YEARS
Results
Overall yield of the search
A total of 68 relevant publications of different levels of
evidence were identified. Details about the search results
in the nine electronic databases as well as in the NTI-tss-
related websites are shown in Tables 1 to 9 and 12, respec-
tively. Figure 3 (right column) reveals by which search
strategy the publications were found: only 39 contribu-
tions were identified by the search in electronic databases
and websites.
Qualitative analysis
The overall qualitative distribution of the relevant publi-
cations according to their strength of evidence is shown in
Figure 4. Figure 3 provides detailed information about the
allocation of the identified 68 articles into the different
levels of evidence.
While no systematic review of RCTs (level I) could be
identified, 13 contributions reported about the results of
clinical studies. Nine of these publications [9,10,16-22]
referred to 5 RCTs (level II). Seven of the nine publica-
tions about RCTs were published in dental journals; one
was a congress abstract [19], and another one was a doc-
toral thesis [21]. Except the thesis, which was written in
Turkish, and a Norwegian article [20], the papers were
published in English. The allocation according to the
Jadad scale is shown in Table 13.
Among the four publications allotted to level III, there
were three congress abstracts [23-25] and one article [26]
about an uncontrolled clinical investigation. Twelve con-
tributions referring to 11 case reports were categorized
into level IV.
Forty-three publications were classified to level V, repre-
senting narrative reviews, editorials, NTI-specific reviews,
brief references to NTI-tss in articles, expert commentar-
ies, and interviews.
Contents-based analysis of the articles on RCTs
The methods and results of the five RCTs are summarized
in Tables 14 to 18. In four studies [9,10,21,22], a com-
plete-arch, hard acrylic resin occlusal stabilization (i.e.
non-repositioning) appliance, which was worn at night,
was used as therapeutic comparison (Tables 14, 15, 16,
17). In the other trial [18], a full-coverage occlusal splint
similar to a bleaching tray was chosen; it was used at night
and during stressful periods during wakefulness. Two
RCTs focused on electromyographic (EMG) investigations
of jaw-closing muscles: In one trial, participants were
diagnosed with TMDs and concomitant bruxism [22]
(Jadad score: 4); in the other study, the only inclusion cri-
terion was bruxism (and associated symptoms) [21]
(Jadad score: 2). In both investigations, the NTI-tss device,
but not the occlusal stabilization appliance, showed a sig-
nificant reduction of the EMG activity. A decrease in clin-
ical symptoms and signs (i.e., pain; number of muscles
with tenderness upon palpation; maximum unassisted
jaw opening) could not be observed [22].
Two RCTs investigated clinical variables in TMD patients.
One of these trials [10] (Jadad score: 5) found no differ-
ence between these two devices, while in the other study
[9] (Jadad score: 3) a stabilization appliance led to a
greater improvement than an NTI-tss device. However,
only descriptive statistics were provided in the latter study
report. In one RCT [18] (Jadad score: 1), patients with
migraine or tension-type headache responded more favo-
rably to the therapy with an NTI-tss device than with a
bleaching tray-like splint.
Complications/side effects related to the NTI-tss-device
While no incidents occurred in the RCTs of Baad-Hansen
et al [22] and Shankland [16-18], complications or side
effects were observed in the other three RCTs [22] (Table
19). Two more incidents [13,27] were identified in the ref-
erence lists of Magnusson et al [9] and Jokstad et al [10],
respectively, while one report was found in a book chapter
[2]. Finally, five cases were published in the FDA Medical
Device reporting website (Table 20).
Different complications and side effects were docu-
mented; however, no case of an aspiration could be
found.
Table 12: NTI-tss-related websites. Results
Web link Relevant hits Cumulative relevant hits Reference/Title
http://www.nti-tss.com 8 8 [10,16,22,23,26,48,73,74]
http://www.ntiamericas.com 3 11 [6,75,76]
http://www.nti-tss.com.br/artigos.htm 9 16 [25,77-80]
http://www.e-motion.eu.com/index.php?name=patients_de 4 18 [17,81]
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Allocation of the identified 68 articles according to the hierarchy of strength of evidenceFigure 3
Allocation of the identified 68 articles according to the hierarchy of strength of evidence. Red: hits in electronic
databases (n = 20); green: publications identified by searching the websites (n = 19); orange: articles found in the reference lists
of identified articles (n = 6); purple: contributions found in textbooks (n = 1); blue: publications mailed by providers of the NTI-
tss device (n = 19); black: publications found in other sources (n = 3).
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Table 13: Assessment of the quality of the articles about randomized controlled trials (RCTs) according to the quality score proposed
by Jadad et al [15]
Study Study described
as randomized?
Method described
and appropriate?
Study described
as blind?
Method described
and appropriate?
Description of
withdrawals/
dropouts?
Jadad score
Baad-Hansen et
al [22]
Yes Not described Yes Yes No withdrawals or
dropouts
4
Kavaklı [21] Yes Not described No --- No withdrawals or
dropouts
2
Jokstad et al
[10,20]
Yes Yes Yes Yes Yes 5
Magnusson et al
[9]
Yes Yes No --- Yes 3
Shankland [16,18] Yes Not described No --- No 1
Discussion
We were surprised to find that within the past decade as
much as nine different trials related to the NTI-tss device
were carried out, five of which were RCTs, while four were
uncontrolled investigations [23-26] (Figure 1). As far as
the estimation of the efficacy of a therapeutic measure is
concerned, it is wise to consider primarily (or exclusively
[28]) articles about RCTs, because they provide the strong-
est evidence on the efficacy of a therapy [29,30]. Numer-
ous examples have shown that observational studies, as
compared to RCTs, are likely to generate over-optimistic
(i.e., false-positive) conclusions [31-33]. Hence, it is not
surprising that in clinical trials without control group the
NTI-tss device was reported to be associated with a
marked decrease in patients suffering from headache [25]
and TMD-associated otologic symptoms (vertigo; otalgia;
otic fullness; tinnitus; subjective hearing loss) [26].
In the five RCTs, which evaluated clinical and electromy-
ographic effects of the NTI-tss device, different inclusion
criteria and methods were used. Therefore, the results had
to be analyzed separately. Each RCT has methodological
weaknesses. Four studies had a limited number of partici-
pants (n = 10 to 38) (cf. Tables 14, 15, 16, 17, 18), which
may have resulted in a statistical type II error (erroneous
acceptance of the null hypothesis), as noted by Jokstad et
al [10]. Shankland's investigation, in contrast, included
94 patients [18]; however, study and reporting quality
were limited. The methodological flaws inherent to this
study are not only reflected by the low Jadad score of 1,
but also by the shortcoming to distinguish between the
diagnoses of migraine and tension-type headache, which
are completely different entities [34]. Shankland excluded
patients with TMDs; however, there is a considerable
symptom overlap between headache and TMD patients
[35]. In fact, the same patient who suffers from pain in the
temples may be diagnosed as having tension-type head-
ache by a neurologist, whereas she may be diagnosed with
myofascial pain in the temporal muscles by a dentist.
Hence, an exact differential diagnosis between the two
entities appears to be nearly impossible. Furthermore,
there are limitations associated with the statistical analysis
of the data gained in this study; for example, no informa-
tion was provided about pre-treatment days of headache
in that study [36].
Focusing on the identified articles about RCTs, two main
indications for the NTI-tss splint may be distinguished:
bruxism and TMDs. As far as bruxism is concerned, the
studies of Baad-Hansen et al [22] and Kavaklı [21] have
shown that – when compared to baseline EMG recordings
from the masseter muscle during sleep – insertion of the
NTI-tss device leads to a significant reduction in EMG
activity of jaw closing muscles during clenching or grind-
ing. These findings are compatible with early results from
Van Eijden et al [37] who found that maximal effort
clenches on the incisal edges of the incisors resulted in a
Qualitative distribution of the identified publications accord-ing to the strength of evidence (cf. Table 1)Figure 4
Qualitative distribution of the identified publications
according to the strength of evidence (cf. Table 1).
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Table 14: Characteristics of the study of Baad-Hansen et al [22]
Study Type of study Aim of the study Patient
recruitment Inclusion criteria Exclusion criteria n Therapeutic
comparison
Baad-Hansen et al [22] Investigator-blinded
randomized
controlled cross-over
trial
1. To compare the
therapeutic efficacy of
two different intraoral
devices on the EMG
activity of bruxers
during sleep.
Self-presentation of
patients at the School
of Dentistry,
University of Aarhus
(Denmark)
1. Self-reported tooth-
grinding during sleep,
confirmed by bed-
partner.
Use of any other
medication than mild
analgesics
10 (average age: not
reported; range: 23–
39 years)
NTI-tss device (n =
10) vs. flat occlusal
stabilization splint
(OS) (n = 10) worn at
night
2. Reports of muscle
soreness on
awakening.
3. Signs of tooth wear.
2. To evaluate if
changes in EMG
activity are associated
with short-term
changes in TMD-
related pain.
4. TMD diagnosis by a
blinded investigator
according to the RDC/
TMD [111].
Study Study duration Outcome
parameters Results Authors' conclusions
Baad-Hansen et al [22] 7–8 weeks 1. "A strong and
lasting inhibition of
EMG activity in
masseter muscles
during sleep was
caused by wearing the
NTI splint but not the
OS. However, this
was not directly
related to the short-
term clinical outcome
measures."
Within-treatment-group pre-post differences "A strong and lasting inhibition of EMG activity
in masseter muscles during sleep was caused by
wearing the NTI splint but not the OS.
However, this was not directly related to the
short-term clinical outcome measures
NTI-tss group:
- Significant decreases at all levels of EMG threshold during the use of the
NTI-tss device when compared with baseline.
OS group:
- No differences between the baseline EMG values for any of the EMG
measures.
Between-groups post-treatment differences
EMG outcomes:
In contrast to the OS, the NTI-tss device was associated with significant
decreases when compared with EMG baseline values.
Clinical outcomes:
- No differences between the two therapies
- No significant correlations between EMG data and clinical variables.
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Table 15: Characteristics of the study of Kavaklı [21]
Study Type of study Aim of the study Patient recruitment Inclusion criteria Exclusion criteria n Therapeutic
comparison
Kavaklı [21] Randomized
controlled trial
To compare the
therapeutic efficacy of two
different intraoral devices
on the EMG activity of
bruxers during sleep.
Self-presentation at the
Hacettepe University
Health Science Institute,
Ankara (Turkey)
1. Self-reported tooth
clenching and tooth
grinding for at least 6
month
1. More than two
missing molars
20 (average age: 31
years; range: 14–52
years)
NTI-tss device (n = 11)
vs. Michigan- type
stabilization splint (SS) (n
= 9) worn at night
2. Grinding sounds
during sleep for at least
3 nights per week as
confirmed by bed-
partner
2. Removable
prosthetic
restoration
3. Jaw muscle discomfort 3. Gross malocclusion
4. Abnormal tooth wear 4. Constant use of
sleep medication
5. Masseter hypertrophy 5. Abuse of alcohol
and/or drugs
6. Diagnosis of sleep
bruxism in a sleep
laboratory
6. Neurological or
psychological diseases
7. Sleeping disorders
8. Internal TMJ
derangements as
diagnosed with an
MRI
Study Study duration Outcome parameters Results Authors' conclusions
Kavaklı [21] 4 months (A) Sleep variables: Within-treatment-group pre- post
differences
1. Both splint designs do not stop sleep bruxism
activity as shown by polysomnographic
evaluation.
- sleep quality
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- total sleep time NTI-tss device: 2. The SS does not reduce the frequency,
duration or intensity of the sleep bruxism.
- sleep efficiency - no changes of other sleep parameters 3. The NTI-tss device reduces the intensity of
bruxism.
- sleep latency - no changes of respiratory parameters 4. Due to its positive effect on sleep bruxism and
its easy adapatability, the NTI-tss device is
recommended if regular check-ups by a dentist
are possible.
- REM latency - no changes in occlusion
- percentages of stage duration - reduced intensity of masseter and temporalis
muscles contraction activities compared to
baseline
- number of awakenings during sleep
- number of movements during sleep
Stabilization splint:
(B) Respiratory variables: - sleep stage 2 was shorter as compared to
baseline
- apnea
- hypoapnea - no changes of other sleep parameters
(C) Bruxism-related variables as derived from
masseter and temporal muscle activity:
- no changes of respiratory parameters
- total bruxism duration - no changes of sleep bruxism activity
- number of bruxism episodes/night
- number of bruxism episodes/h Between-groups post- treatment
differences
No changes
- number of bruxism burst/episode
- number of bruxism burst/h
- amplitude of bruxism episodes
Table 15: Characteristics of the study of Kavaklı [21] (Continued)
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Table 16: Characteristics of the study of Jokstad et al [10,19,20]
Study Type of study Aim of the study Patient
recruitment
Inclusion criteria Exclusion criteria n Therapeutic
comparison
Jokstad et al
[10,19,20]
Investigator-blinded
randomized
controlled trial
To compare the
therapeutic efficacy of
two different
intraoral devices in
TMD patients.
TMD patients
referred to or
applying for therapy
at the Department of
Prosthetic Dentistry
and Stomatognathic
Physiology, Faculty of
Dentistry, University
of Oslo (Norway)
Adults who had
experienced TMD
symptoms for at least
6 months, e.g.,
1. Partial protheses
with distal extensions
38 (average age: 37
years; range: 17–62
years)
NTI-tss device
(n = 18) vs. Michigan-
type stabilization
splint
(SS) (n = 20)
- impaired range of
motion
2. Additional TMD
therapy during the
trial
- impaired TMJ
function
3. Recent facial or
cervical trauma
worn at night
- muscle pain
- TMJ pain
- pain on mandibular
movement
Plus (both groups):
1. counseling
2. muscle relaxation
exercises
Study Study duration Outcome parameters Results Authors' conclusions
Jokstad et al
[10,19,20]
3 months - Self-reported headache and TMD-related
pain on a 100 mm VAS
Within-treatment-group pre-post
differences
1. The therapeutic efficacy between an NTI-tss
device and a Michigan splint did not differ over
an observation period of three months.
- Maximum unassisted jaw opening - Average jaw opening increased in both
groups
- Tenderness on palpation of masticatory
muscles, neck and shoulder muscles and TMJs
on a 100 mm VAS
- VAS scores for TMD-related pain and self
reported headache decreased significantly
between baseline and 3-months examination
in both groups
- Reduction of jaw muscle (but not neck and
shoulder muscles) tenderness upon palpation
in both groups
- No changes of TMJ tenderness upon
palpation
Between-groups post-treatment
differences
- Comfort of splint use on a 100 mm VAS - No differences between NTI-tss and SS
groups at the 3-months examination
- In both groups, the comfort of splint use
appeared to be similar at each control
examination with a (statistically not significant)
trend of higher comfort for the NTI-device
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Table 17: Characteristics of the study of Magnusson et al [9]
Study Type of study Aim of the study Patient
recruitment
Inclusion criteria Exclusion criteria n Therapeutic
comparison
Magnusson et al [9] Investigator-blinded
randomized
controlled trial
To compare the
therapeutic efficacy of
two different
intraoral devices in
TMD patients.
Patients referred for
suspected TMDs to
the Department of
Stomatognathic
Physiology, the
Institute for
Postgraduate Dental
Education, Jönköping
(Sweden)
1. TMD symptoms ≥
6 months
1. Ongoing TMD
therapy
28 (average age: 31.5
years; range: 16–70
years)
NTI-tss device
(n = 14) vs. Michigan-
type stabilization
splint (SS) (n = 14)
worn at night
2. Age: ≥ 16 years 2. Therapy with any
kind of interocclusal
appliance during the
past year
3. ≥ 12 teeth both in
the upper and lower
jaw
3. TMD symptoms
and signs justifiying
another initial therapy
than an interocclusal
appliance
4. Moderate or
severe clinical signs
according to
Helkimo's Clinical
Dysfunction Index
4. Anterior teeth with
periodontitis or fixed
partial dentures
5. Pronounced
subjective symptoms
according to
Helkimo's
Anamnestic Index
5. Pronounced pre-
or postnormal
occlusion
6. Frequent tension-
type headache
6. Deep bite
7. Psychic disorder
8. Language difficulties
Study Study Duration Outcome parameters Results Authors' conclusions
Magnusson et al [9] 6 months - Mandibular mobility Within-treatment-group pre-post
improvement
1. "The almost 100% treatment success that
have been claimed after NTI treatment could
not be confirmed in this study."
- Deviation/deflectio 6-month follow-up of the NTI-group (n = 10): 2. "The statement of a gain in chair-side time
with the NTI device can be questioned. The
use of NTI devices, however, eliminates one
clinical visit, as well as the laboratory costs."
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- n on jaw - significant improvement (n = 6) 3. "It can not be ruled out that long time use
of NTI splints can be detrimental for the
occlusion."
- opening - some improvement (n = 1) "All of the studied variables were in favour for
the stabilization splint, compared to the NTI
device."
- no change (n = 2)
- TMJ sounds - impairment (n = 1)
- Pain on mandibular movement - impaired occlusion (n = 1)
- Muscle/TMJ pain upon palpation - decreased use of analgetics
(n = 2)
- Number of occluding teeth - increased use of analgetics (n = 2)
- Time for impression-taking, interocclusal
recording and adjustment of stabilization splint
- 6-point behavior scale: 3.4 → 2.1
- Time for fitting and adjustment of the NTI-
tss device
- 11-point numerical scale: 5.9 → 3.8
- Adherence to the allocated splint 6-month follow-up of the SS-group (n = 14):
- Use of analgetics - significant improvement (n = 12)
- Symptom intensity (6-point behavior scale,
11-point numerical scale)
- some improvement (n = 2)
- decreased use of analgetics
(n = 10)
- 6-point behavior scale: 3.4 → 1.9
- 11-point numerical scale: 5.9 → 3.3
Between-groups post-treatment
differences
- 3-month follow-up: 4 patients with NTI-tss
device changed to SS due to impairment or no
improvement of their symptoms, while none
of the SS users changed the group.
- For all variables, improvement was larger in
the SS-group than the NTI-group
- SS-appliances were judged to be more
comfortable than the NTI-tss device
Mean production time
- NTI-tss device: 27 minutes
- SS: 17 minutes
Table 17: Characteristics of the study of Magnusson et al [9] (Continued)
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Table 18: Characteristics of the study of Shankland [16,18]
Study Type of study Aim of the study Patient
recruitment
Inclusion criteria Exclusion criteria n Therapeutic
comparison
Shankland [16,18] Randomized
controlled clinical
trial
To evaluate the safety
and effectiveness of
the NTI-tss device for
the reduction of
frequency and
severity of tension-
type and migraine
headaches.
Not reported 1. Diagnosis of
tension-type or
migraine headaches
Presence of TMDs 94 (average age and
range: not reported)
NTI-tss device
(n = 51) vs. full-
coverage occlusal
splint without cuspid
rise and anterior
guidance (similar to a
bleaching tray) (n =
43) worn at night and
during the day when
perceiving stressful
periodes
2. Intake of
Sumatriptan as a
rescue medication
3. 3. Having
experienced an
average of two
migraine episodes or
8 tension-type
headaches per month
4. Presence of natural
or fixed prosthetic
maxillary and natural
mandibular incisors
5. Overbite and
overjet within normal
limits
6. Stable dentition
with no current
orthodontic
treatment and fully
erupted teeth
7. No significant
periodontal disease
8. No TMD signs and/
or symptoms
9. At least 18 years of
age
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Study Study duration Outcome parameters Results Authors' conclusions
Shankland [16,18] 4 weeks baeline data
+ 8 weeks therapy
(A) Clinical objective outcomes: Within-treatment-group pre-post
differences
1. "The NTI-tss appliance proved safe and
efficacious in the reduction of medically
diagnosed migraine and tension-type
headache."
- Interocclusal record NTI-tss group:
- Tooth mobility of all anterior teeth - 16% of the participants reported an 85% to
100% reduction of migraine headaches
- Tooth sensibility of the anterior teeth
(temperature, pressure)
Users reported an elimination of 46.9% of all
headache pain as well as reduction of
photophobia, phonophobia and nausea
- Periodontal health of all teeth Control group:
- Periapical radiographs of the anterior teeth - 7% of the subjects reported a 85% to 100%
reduction of migraine headaches
- Vitality of the anterior teeth - 27% of the subjects reported an average 46%
increase in migraine events
- Tenderness of the head and neck muscles - Increase of migraine frequency
- Trigger points Between-groups post-treatment
differences
- Range of mandibular motion - In every category (headache episodes,
dosages of rescue medicine (Imitrex®),
phonophobia, photophobia, nausea), the
percentage of reduction of all symptoms
decreased for those in the NTI-tss group.
- TMJ noises
- TMJ tenderness
- Tension-type headache
- Migraine headache
- Nausea
- Photophobia
- Phonophobia
- Analgesics taken (and doses)
- Use of rescue medicine (Sumatriptan®)
(B) Clinical subjective outcomes (VAS):
- Intensity of tension-type headache
- Intensity of migraine
Table 18: Characteristics of the study of Shankland [16,18] (Continued)
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significant decline of EMG activity as compared to clench-
ing in intercuspation.
The fact that Baad-Hansen et al [22] were unable to corre-
late their EMG findings with clinical symptoms (e.g.,
reduction of reported pain) may be due to the short dura-
tion of wearing the intraoral device (2 weeks). Data from
other investigations suggests that a decrease of EMG activ-
ity may indeed be associated with a pain reduction in
patients with masticatory muscle pain [38]. Moreover, a
decrease of EMG activity is not a unique characteristic of
the NTI-tss device, but may be achieved with any anterior
bite stop [39], sometimes even with a full-coverage occlu-
sal appliance [38]. Hence, we concur with Clark and
Minakuchi [2] who suggest in their recent review on oral
appliances that it is "reasonable to use a partial-coverage
Table 19: Complications and side effects associated with the use of the NTI-tss device as described in the identified publications
Study Complications/Side effects
Clark & Minakuchi [2] • Anterior open bite induced after wearing the device 24 hours a day over an extended period of time (n = 1)
Kavaklı [21] • Radiologically diagnosed widened periodontal ligament plus alveolar bone resorption in one tooth (n = 1/20)
Jokstad et al [10] • Sensitive lower front teeth (n = 1/18)
• Dryness of the mouth while sleeping (n = 6/18) due to a forced open jaw caused by the NTI-tss design
• Swallowing difficulties (n = 2/18)
• The protruding tip of the device was felt to be annoying (n = 1/18)
• The device was falling out or being taken out unconsciously while sleeping (n = 2/18)
Magnusson et al. [9] • Altered occlusion between the 3- and 6-month follow-up: "the vertical overbite decreased with one millimeter, and the
number of occluding tooth pairs was reduced from 10 to 15" (n = 1/14)
• Transient tenderness in the teeth when the device was used (n = 6/14)
• Tongue thrusting, dry mouth, increased salivation, snoring (as reported by "single patients")
Fleten & Gjerdet [13] • Swallowing of an NTI-tss device, which was lodged at the esophageal entrance (n = 1)
Fitins [27] • Sensitive and painful maxillary central incisor (n = 1)
• Moderate mobility of and local bone loss around three maxillary incisors
Table 20: Complications and/or side effects as described in the MAUDE database
Web link Year Complaints/Side effects
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/
Detail.CFM?MDRFOI__ID=471018
2003 "This device [...] will not stop migraines, it took out pt's two front crown
teeth, it causes tooth movement, joint strain [...]. This device is harmful –
dangerous and it is not therapeutic. Pt had to have surgery to undo the
harm that was caused by the nti splint"
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/
Detail.CFM?MDRFOI__ID=551955
2004 "[...] the device was not only ineffective, but has done damage to their jaw
alignment, bite, and facial appearance. The device caused them to grind
their front teeth instead of their molars. Even though rptr only wore it for
two weeks, rptr's jaw and their bite has not returned to "normal". During
the two weeks rptr wore it, rptr suffered extreme headaches, facial pain,
and their front teeth loosened. [...] Rptr's teeth are actually moving position
since rptr can barely bite down without forcing their lower jaw back. Their
front teeth are shifting back because they are constantly pushing against
their upper teeth. Eating and chewing is challenging since they can't actually
touch their upper and lower molars together without effort. Therefore,
rptr's lower jaw spasms when they chew."
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/
Detail.CFM?MDRFOI__ID=557167
2004 "Pt's concern is that this device poses a significant threat of death by
choking. [...] A user could dislodge the nti-tss with the tongue, or, during
sleep, unconsciously reach into the mouth to loosen or readjust it it is very
uncomfortable-. If it remained in the mouth it could easily become lodged in
the throat."
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/
Detail.cfm?MDRFOI__ID=753670
2006 "Since the implant was put in, patient has been having migraine headaches
and a clicking jaw. [...] Her teeth have moved so much that according to the
dentist, she would need braces to move her teeth to position. Patient never
had a history of migraine."
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfMAUDE/
Detail.cfm?MDRFOI__ID=765535
2006 "Not only is his new apparatus devoid of a safety device to keep him from
swallowing it in his sleep, but (1) it fit very tightly and (2) it was very difficult
to remove. When he did take out the device, it felt as if he was going to pull
his teeth out. Last night, when he went to sleep, he was awakened when
the device broke in his mouth."
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anterior bite appliance in those patients with a known
tooth-clenching habit, because this habit cannot be con-
trolled with a stabilization appliance." On the other hand,
a hard acrylic resin stabilization splint may be helpful in
patients with tooth grinding, because it helps preventing
the unwanted consequence of sleep bruxism [40], such as
tooth wear (attrition), tooth grinding sounds, and – often
– associated pain [41].
Regarding the management of patients with (localized)
TMDs (e.g., myofascial face pain and/or arthralgia of the
TMJs), the use of stabilization appliances is sufficiently
supported by evidence in the dental literature [42-45].
Türp et al [45], for instance, concluded after a systematic
review of the literature that most patients with mastica-
tory muscle pain are helped by the incorporation of a sta-
bilization splint. Particularly patients with local pain of
the myofascial muscles (as opposed to individuals with
widespread pain) are likely to experience improvement
from this therapy [46].
Helkimo's statement that there is "no peer-reviewed scien-
tific publication that exhibits that the NTI-splint is supe-
rior to other well-established conventional splints for the
treatment if [sic] functionally related facial pain or man-
dibular dysfunction" [8] still holds true: a superiority of
this anterior bite stop has not yet been shown. Nonethe-
less, the currently best available evidence [10] suggests
that for the management of TMDs the NTI-tss device is
similarly efficacious as a stabilization appliance. This
demonstrates, on the other hand, that the observed reduc-
tion in clinical symptoms is not a feature unique to the
NTI-tss device. Instead, it may also be achieved with other
splints, even with other forms of anterior bite stops: Nil-
ner et al [47], for instance, observed in patients suffering
from myofascial face pain that at 6- and 10-weeks follow-
up appointments a prefabricated appliance covering the
six upper front teeth may be as effective in pain improve-
ment as a traditional stabilization appliance. In a patient
group with the same diagnosis, Al Quran and Kamal [48]
who inserted an NTI-tss-like device (AMPS: anterior mid-
line point stop) reported similar clinical results after 1
month and 3 months.
The positive effect after the incorporation of any type of
appliance has frequently been explained by patient-spe-
cific behavioral changes [2]. However, such an assump-
tion is hard to justify given the fact that the splints are
usually worn at night during sleep, as it was also the case
in the RCTs reviewed here. Regarding localized myofascial
pain of the masticatory musculature, an alternative expla-
nation is based on the heterogeneous activation capability
of these muscles [37,49-51]: Experimental results in
healthy volunteers indicate that a temporary positional
alteration of the mandible (e.g., an increase of the vertical
dimension after insertion of an occlusal appliance)
changes the intramuscular recruitment pattern, which is
often followed by a pain reduction [52-55]. Although this
biomechanical hypothesis needs further studies to be val-
idated [56], it provides a physiologically plausible expla-
nation for the therapeutic success gained with oral splints.
We were unable to find evidence for the statement that the
NTI-tss device was indicated for the prevention of brux-
ism, TMDs, chronic tension-type headaches, migraine, or
occlusal trauma. Likewise, due to the poor quality of the
publications by Shankland [16,18,17], its use for the ther-
apy of migraine remains doubtful.
Contrary to claims made in the dental literature [10,12],
cases of aspirated NTI-tss devices could not be identified
in the present review (c.f. Tables 19 and 20). None of the
five reports published in the MAUDE database referred to
such an event. Fleten and Gjerdet [13], who allegedly
reported about an aspiration, presented a case where an
NTI-tss splint was lodged at the esophageal entrance.
Nonetheless, possible side effects, particularly those
related to the teeth and the occlusion, remain the greatest
concern when wearing NTI-tss splints (cf. Table 20). Of
course, adverse events may also occur when a stabilization
appliance is used. Clark and Minakuchi [2] mention two
concerns which, albeit rare, need to be considered in this
context: (a) increase of clenching activity when wearing
the bite splint; (b) unintended occlusal change after full-
time use, due to alterations of the position of individual
teeth or of the mandible. However, if a stabilization appli-
ance is worn at night only – and, if needed (e.g., during
stressful periods of life), additionally during one or two
hours of the day – the development of an appliance-
induced malocclusion is unlikely. Other side effects, such
as increased or decreased salivation [57], are usually
short-lasting, while tension in the teeth [57] can mostly be
eliminated by careful adjustments along the labial and/or
buccal surfaces that ensure the retention of the stabiliza-
tion appliance. Since it is certain that published case
reports represent only a fraction of all adverse events that
have occurred while using any type of intraoral appliance,
clinicians should be encouraged to frankly report any
unintended negative outcome associated with splint ther-
apy. In the hierarchy of scientific evidence, case reports
represent a low level (cf. Table 9). Nonetheless, consider-
ing the absence of other data we believe that the publica-
tions summarized in Tables 19 and 20 deliver valuable
information and convey an important message to the cli-
nician (as well as to the patient), namely that the use of
the device is not fee of risks. Unfortunately, no risk quan-
tification is possible at this point in time. Meanwhile, it
remains crucial to take care that a patient receiving an
NTI-tss device remains compliant with follow-up
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appointments, especially when wearing it over an
extended period of time.
It has been argued that an advantage of the NTI-tss splint
as compared to a conventional occlusal bite splint is the
reduced chair-side time. Therefore, some dentists are
likely to be surprised when confronted with Magnusson et
al's report [9] that on the average 27 minutes (range: 17–
45 minutes) were needed to fit and adjust an NTI-tss
device as opposed to 17 minutes (range: 11–26 minutes)
for making interocclusal records, taking impressions, and
adjusting the surface of a stabilization appliance. Indeed,
this computation appears to be debatable. In a previous
study it was shown that the average time required for
chair-side adjustment of a stabilization appliances (fabri-
cated without and with face-bow) was less than 11 min-
utes (range: 4–27 minutes) [58]. To determine centric
relation by fabricating an interocclusal record and to
make alginate impressions of the upper and lower jaw one
may calculate additional 15 minutes. Hence, for making a
stabilization appliance the dentist needs to be at the chair
for about 25 to 30 minutes, which corresponds to the time
frame reported by Magnusson et al [9] for preparing an
NTI-tss device. Yet, it should be noted that an inexperi-
enced clinician may need considerably more time for
either device.
The occlusal stabilization splint [59] remains the "gold
standard" for the therapy of patients with (particularly
localized) temporomandibular pain (i.e., myofascial pain
of the masticatory muscles; TMJ arthralgia) and/or brux-
ism because it "is an easily used, potentially long-term,
and clinically effective treatment intervention with rea-
sonable nightly patient compliance and good outcomes,"
thereby exhibiting "few potential complications [2]."
Conclusion
There is evidence from RCTs that the NTI-tss bite stop may
be successfully used for the management of TMDs and
bruxism. However, to avoid potential side-effects, it must
be ensured that the patient is willing to return regularly to
the dentist's office for control sessions and, if needed, re-
adjustments. If this prerequisite is fulfilled, the NTI-tss
splint may be particularly justified in the following clini-
cal situations:
• A patient with acute and intense temporomandibular
pain (possibly accompanied by a restricted jaw opening),
who requires (as an emergency therapy) the rapid incor-
poration of an oral appliance to increase the vertical
dimension of the jaws.
• A reduction of the EMG activity of jaw closing muscles
during jaw clenching or tooth grinding is desired.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
JCT designed the systematic review, HS carried out the sys-
tematic literature search. HS and JCT appraised the identi-
fied publications, and drafted the manuscript. Both
authors read and approved the final manuscript.
Acknowledgements
We are grateful to Dr Babür Taner, DDS, Dr. Med. Dent., University of
Basel, for the translation of the thesis by Y. Kavaklı (2006) from Turkish
into German.
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